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BACKGROUND OF THE INVENTION
There has been renewed interest in the development of fluorescent lamps in the last few years. Numerous new forms and models have come on the market, especially in the field of compact fluorescent bulbs which can be used as replacements for conventional incandescent bulbs in existing lamp assemblies.
Simultaneously with these developments in the field of fluorescent lamps, the use of halogen bulbs has increased enormously. The small size of halogen bulbs results in flexible possibilities for using such bulbs in a variety of applications and has made possible the creation of new lamp construction forms. Halogen lamps have become a construction kit element which makes it possible even for hobbyists to realize their own ideas of new lighting systems.
This possibility has been hitherto absent with respect to fluorescent lamps. The high production costs of fluorescent bulbs compel extreme automatization and prevent a flexible adaptation to wishes of the market.
SUMMARY OF THE INVENTION
The problem addressed by the present invention is to create also for fluorescent lamps a module system similar to a construction kit which makes it possible to form flexible variations for lights of every type.
According to the present invention this problem is solved by providing fluorescent lamps that consist of one or more one-side socketed gas discharge vessels or fluorescent bulbs as lighting elements, and with one or more choke devices constructed as separate units which can be connected with the lighting elements over plug connections, the lighting elements constructed as small standard modules having low light output and having a glass tube diameter of the fluorescent bulbs not over 13 mm, so that they are pluggable singly or in groups into different housings.
The basic idea lies in combining several low-power standard modules, instead of high power gas discharge vessels, which are complicated to manufacture.
The housings can be provided with connecting parts, for example with an Edison winding E 27 or a bayonet socket B 22 , so that they can be used in an existing light body as replacements for conventional incandescent lamps.
For use in new light constructions, it is simpler to provide the housings or the choke devices present in them with electrical connectors specially adapted for this application, for example wire connectors. The use of a specially designed connector to supply current to the lamps not only avoids the costs for the contact-hazardous lamp holders E 27 , but also the installation measurements of the lamps are substantially reduced.
In view of the low output of the individual fluorescent bulbs, it is also possible to substantially reduce the expenditure for the requisite current-limiting choke devices and to provide, according to the invention, a separate choke device for each standard module. Insofar as is appropriate, certain component groups, for example the current supply, can be allocated in common for several connecting devices.
The design used to manufacture the pluggable standard modules should be as economical as possible. According to the invention, therefore, it is recommended that the pluggable connections of the gas discharge vessel be constructed as plug pins which are fused directly to both ends of the gas discharge vessel.
In order to better secure the bulbs or standard modules against dropping out of the lamp fixture or lamp housing, it is further recommended that arresting or locking means be provided to hold the bulbs in place. The arrangement of reflector surfaces, especially with lamps with only one U-shaped gas discharge vessel, improves not only light distribution but can also serve simultaneously as a support for the individual standard light modules after it is plugged into the housing.
In instances where several fluorescent lamps or standard modules are employed, a special advantage of the invention lies in the fact that if one module fails or drops-out, the lamp assembly is capable of continued operation, and later only the faulty module has to be replaced.
If so desired, it is also possible to exchange modules of different form and color in a given lamp without high costs.
BRIEF DESCRIPTION OF THE DRAWINGS
For the better understanding of the concept of the invention reference is made to the following figures:
FIGS. 1 to 10 show five different examples of standard modules according to the present invention;
FIGS. 11 to 14 show axial plan views of fluorescent lamps or housings with one, two, three and four plugged-in standard modules or fluorescent bulbs;
FIG. 15 represents a compact lamp with three plugged-in standard modules, corresponding to the representation in FIG. 13;
FIG. 16 shows schematically a lamp according to the invention with two standard modules plugged into a housing which contains the choke devices and connecting possibilities for mains feed lines;
FIGS. 17 and 18, (also shown respectively as 21 and 22 ) present further examples of compact fluorescent lamps such as were not producible with the technologies hitherto used;
Also the example of a light band, in FIGS. 19 and 20, schematically shows the new possibilities using standard modules in accordance with the invention;
FIG. 23 is a schematic example of a choke device for use with three standard modules; and
FIG. 24 is a schematic view of a component for lighting which uses a standard module according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
The following thorough description of the examples according to the invention is in no way to be regarded as limiting, since many details according to the invention can be combined and varied.
FIGS. 1 to 10 show, first of all, different variations of standard modules according to the invention. Numerous combination possibilities are yielded through the fact that four basic elements can be changed, namely:
the form of the gas discharge vessel ( 1 ),
the type of electrical contacts,
the form of the electrodes,
the form of the arresting means.
FIG. 1 shows a gas discharge vessel or flourescent bulb ( 1 ) such as is produced at present mainly by PHILIPS, consisting of two straight glass tubes which are joined at the upper end according to the “Hot Kiss” process. The smooth plug pins ( 2 ) and their arrangement are represented in FIG. 2 .
FIG. 3 shows the form, in most widespread use today, of a gas discharge vessel ( 1 ) bent in U-form with very small spacing of the glass tube halves, such as are necessary for the construction of gas discharge vessels with relatively high capacity. As example of a pluggable contact means there are provided contact surfaces ( 4 ) the arrangement of which is to be seen in FIG. 4 .
FIG. 5 likewise shows a U-shaped gas discharge vessel, having a greater radii of bending, which substantially facilitate the manufacture of such bending parts. In this example the plug pins ( 22 ) are fused-in with constrictions directly at the ends of the gas discharge vessel ( 1 ) by means of pen-feet ( 12 ). The cold cathodes ( 11 ) provided in this example require only one plug pin ( 22 ), so that FIG. 6 represents an extremely simple and economical arrangement of this invention.
FIG. 7 shows as a further example a V-shaped gas discharge vessel ( 1 ) with smooth plug pins ( 2 ) which are fastened in caps 8 ) and fastened with these to the ends of the gas discharge vessel ( 1 ). In such an arrangement the stability of the ( 24 ). The pocketing or fixing-in-place of the standard module could be realized, for example, by a stop spring ( 25 ) which snaps into place on the upper edge ( 31 ) of a cap ( 8 ). Such a stop spring could, of course, also engage on the crosspiece ( 24 ) or another profiling of the caps ( 8 ), in which case of course it is fastened to the housing in which the module is plugged. FIG. 8 shows the view in the direction of the pins ( 2 ) and the stable construction of this variant.
FIGS. 9 and 10 show another example of a flat-building gas discharge vessel ( 1 ) with greater spacing of the ends of bulb ( 1 ) which are provided with heated electrodes ( 17 ), in which the plug pins are fused with rest means ( 3 ) directly in a squeeze-foot ( 13 ) of the gas discharge vessel ( 1 ). As can be seen in FIG. 10, in this example the four plug pins are provided with socket means ( 3 ) and arranged in a line. The result is that the production tolerances of the glass parts need be maintained less critically, even if the springy counter-contacts are aligned in the same direction.
FIGS. 11 to 13 make evident the immense advantages of the construction of a fluorescent lamp according to the invention. With one and the same standard module there can be constructed a simple execution of the invention—a bulb ( 1 ) having a relatively low light output—as represented in FIG. 11 —as well as lamps with two vessels or modules (FIG. 12 ), three modules (FIG. 13) and four modules, as in FIG. 14 .
In FIG. 11 there is also to be perceived a support ( 26 ) which is mounted on the housing ( 5 ). A similar support ( 26 ) is shown also in FIG. 12 for two gas discharge vessels ( 11 ). The function of supports ( 26 ) can best be recognized in FIG. 16, where in a side view there are recognizable fork-shaped guides ( 28 ) which have the function of securing the gas discharge vessels ( 1 ) against lateral movement after the plugging-in of the standard modules.
The depression ( 30 ) in FIG. 12 has the function of avoiding any danger of contact of the pins ( 2 ) while plugging-in the modules, a safety feature which is lacking in conventional Edison sockets (e.g., FIG. 15 at ( 7 )).
In FIG. 13 there can be perceived a further advantage of a standard module with greater pin spacing according to FIG. 5 or FIG. 7 . Hitherto the close bending of the U-shaped gas discharge vessels according to FIG. 1 or 3 did not make it possible to utilize the interior space between the gas discharge vessels, in order, for example, to be able to accommodate in a space-saving way a choke device ( 6 ) or at least parts thereof The same holds also with superstructures with four standard modules, as represented in FIG. 14 . The advantage of such an arrangement is clearly apparent from the representation in FIG. 15 . Here it can be seen that the housing ( 5 ) can be constructed substantially shorter, since at least parts of the choke device ( 6 ) are accommodated centrally between the individual modules. In FIG. 15 also the housing of a compact lamp is represented, i.e. a lamp which can be attached to a connecting part ( 7 )—in this case provided with an Edison winding E 27 —and screwed into a usual-type incandescent lamp socket.
As distinguished from the embodiment of FIG. 15, which is designed for use with conventional lamp sockets, for new constructions of illuminating bodies, a solution according to FIG. 16 is proposed. In this case, the socket housing ( 27 ), or the choke device ( 6 ) accommodated in it, is provided with connecting means, for example terminals, so that the connecting wires ( 29 ) can be connected directly with the choke device ( 6 ). Therewith there is eliminated the use of non-contact-safe socket E 27 , which has led to numerous, accidents, some of them fatal ones. With the introduction of a socket such as the one according to the invention it is possible not only to save costs, but also to obviate a dangerous component.
The use of standard modules according to the invention also makes possible lamp constructions which were not feasible according to technologies hitherto employed.
FIGS. 17 and 18 show such a compact lamp with connecting part ( 7 ), again an Edison winding E 27 , which, of course, can also be replaced by a bayonet socket or other standardized connecting parts. The gas discharge vessels ( 1 ) are obliquely arranged in the housing ( 5 ) in this example, and they give a substantially better light distribution in the axial direction of the lamp than is attainable with the compact lamps of hitherto. FIG. 18 shows an axial view of the lamp of FIG. 17 . Here there is represented the possibility of utilizing bulbs or gas discharge vessels ( 1 ) of differing types, for example to the gas discharge vessels ( 10 ) shown with angularly bent glass tubes.
The compact lamp as represented in FIG. 21 is distinguished by flat light radiation such as is often desired for the aesthetic arrangement of rooms, but hitherto could not be supplied. The axial representation of the same lamp in FIG. 22 shows the expedient and elegant formation of such a lamp, which can be further enhanced by the use of special bulbs or modules ( 9 ) which have circular bendings in conjunction with arcuate bulbs ( 1 ).
The possibilities for forming gas discharge vessels ( 1 ) having difference geometries are not exhausted by the examples of the gas discharge vessels ( 9 ) or ( 10 ). For a creative formation of the glass bending parts according to the invention, the gate is open, since the necessity of having to join glass parts with one another in “Hot Kiss” lamps is eliminated by the use of a plurality of smaller fluorescent bulbs ( 1 ).
Accordingly, a light strip according to FIGS. 19 and 20 is possible, in which individual modules can be arrayed linearly next to one another. Practically, the number of gas discharge vessels ( 1 ) which can be plugged into a housing ( 19 ) is not limited. Light strips built up in this manner can be fastened, for example, to a ceiling ( 18 ), as shown in FIG. 19 . Whether there are used here only the standard modules lying parallel to the ceiling ( 18 ), or whether there are possibly provided in the ceiling edges an angularly arranged solution of standard modules, depends merely on the taste of the customer.
The construction of chandeliers by means of standard modules is favored by a construction such as represented in FIG. 24 . Here the gas discharge vessel ( 1 ) as standard module is inserted into a socket housing ( 27 ) on the end of which the usual 10 mm tubes ( 23 ) are installed, as they are used in the construction of illumination bodies. With such construction elements that make use of standard modules there is yielded in actual fact a construction kit system which opens up new horizons for lighting architects and designers of lighting system.
Although the proposal of the invention to replace, for example, an 18 watt fluorescent lamp with three standard modules of 6 watts appears more expensive, on exact analysis one comes to the following result.
The fully automatic manufacture of a much larger number of cheaply producible standard modules reduces the investment costs and piece costs mightily—finally one needs, for example instead of one 18 watt lamp, three modules of 6 watts, but with lower total costs.
Moreover, the advantages of an economical manufacture of this type of bulb, savings in stocking and in service, higher operating security, the eliminated danger of contact between voltage-conducting parts, and lower price, speak in favor of the new module system.
Fluorescent lamps of low capacity can be operated, for example, with simple capacitor choke devices, which cost less than an electronic 18 watt connecting device, especially when it can be constructed according to FIG. 23 in such manner that a common current supply ( 15 ) and three current-limiting means ( 16 ) which are coupled on the outlet side supply the gas discharge vessels ( 1 ). In particular the use of cold cathodes ( 11 ) and ( 20 ) simplify such a circuit. The cold cathodes ( 20 ), moreover, can be connected by a common return line ( 21 ) with the current supply ( 15 ), which is connected to the mains ( 14 ).
Although it has always been conceptually possible to develop gas discharge lamps of low capacity as modules and to use several of them as replacement for fluorescent lamps of greater capacity hereto for taken advantage of this opportunity at least in the form here represented. The new module construction kit opens up completely new possibilities. Architects and light manufacturers are freer in their possibilities of execution, the solution to lighting problems is facilitated, stimuli for do-it-yourself hobbyists are provided and altogether it is possible to expect, as a synergy effect, that the willingness to save energy will be increased by the use of inexpensive module fluorescent lamps.
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The invention concerns a construction kit system for fluorescent lamps ( 1 ) with separate choke unit. Standard low-power modules which are cheap and easy to manufacture can in particular be plugged in any combinations into choke units fitted as compact lights or in lamp housings. A number of examples are given to show the new possibilities for constructing lighting systems. These fluorescent lamps each have a replaceable light element comprising at least one gas discharge vessel ( 1 ) with a base at one end as the light element and at least one choke unit ( 6 ) in the form of a separate unit fitted in a housing and capable of electrical connection via plug connectors ( 2 ) to the light element. The light element is designed as a standard low-power module with a glass tube diameter of the gas discharge vessel of no more than 13 mm, thus allowing it to be plugged into different housings individually or in groups.
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THE FIELD OF THE INVENTION
This invention relates to locomotion devices primarily for children. More specifically, this invention relates to a scooterlike device which is adapted for use with wheels on improved hard surfaces and with skids for use on snow-covered surfaces.
BACKGROUND DISCUSSION
(a) Prior Art
Skateboards and skateboard hardware are well-known in the prior art. Essentially, a skateboard comprises a board approximately 8"×24" to which pairs of skateboard wheels are attached to the underside of the board, front and back. This device is inherently dangerous and should not be used without proper training, supervision and protective clothing. In particular, skateboards should not be used by young children. Two-wheeled and three-wheeled scooters are also well-known in the art. Neither skateboards nor scooters can function in snow. The present invention is an improvement over both of these prior art devices without having their disadvantages.
(b) General Discussion of the Invention
The subject invention is an all-season toy which utilizes the performance attributes of skateboards while minimizing their propensity for inflicting physical injury on their users. In addition, the subject invention makes available to younger children the pleasures of a safe toy which provides the enjoyment of a skateboard. In its preferred embodiment, the subject invention combines the safety of a conventional two-wheeled or three-wheeled scooter with the performance characteristics of a conventional skateboard. In addition, the subject invention includes unique safety provisions which render the invention superior to either a scooter or a skate-board. Of particular interest with respect to this invention is the fact that the invention can be retrofitted from summer use to winter use by substituting skids for skate wheels. Thus, what is disclosed herein is a toy for all seasons.
The preferred embodiment of the invention comprises an elongated foot board to which is attached a collapsible impact superstructure to the front top side of the board. Novel foot-operated brake means are secured to the rear portion of the board. Conventional skateboard wheels or snow skids are secured to the underside of the board, front and back. The collapsible impact structure, in appearance only, is patterned after the traditional orange crate which was so popular for use in homemade scooters generations ago. Although wood for toys has fallen somewhat into disuse in recent times, wood has excellent physical properties for the purposes of this invention. Thus, wood is sufficiently rigid to provide stability, balance and as a rest for the user's hands for steering purposes. In addition, with a proper selection of threaded fasteners, wood can be adapted to yield upon impact beyond a predetermined force. Accordingly, the simulated wooden orange crate will absorb energy by deformation and thereby minimize the consequences of impact upon the user due to a sudden accidental stop.
The foot brake comprises a U-shaped board which fits about the rear end portion of the foot board. By stepping on the brake board, the rider forces the brake board into frictional contact with a speed-retarding surface. When the device is wheelmounted, the brake board makes frictional engagement with the wheels. When the device is skid-mounted, a brake board attachment mades contact with the supporting surface.
OBJECTS OF THE INVENTION
It is, therefore, among the objects of this invention to provide a foot-assisted locomotion device which: can be safely used by young children; combines the enjoyment of a skateboard with the safety of a scooter; has unique safety provisions to render the device superior to either a scooter or a skateboard; has a unique foot brake means for coaction with skateboard type wheels or snow-covered surfaces; has a foot brake which can be easily actuated by a small child; has a collapsible impact device positioned in front of the rider to absorb the energy of impact in the event of an accidental head-on collision; is easy to steer and is safe to ride; and which can be easily retrofitted with skids for use on snow-covered surfaces.
These and other objects, features and advantages of the invention will become apparent in view of the following detailed description of the preferred embodiments shown and described herein and as illustrated in the accompanying drawings in which:
FIG. 1 is a perspective view of a preferred embodiment of the invention equipped with wheels for summer use;
FIG. 2 is a fragmentary side elevational view taken along the line 2--2 of FIG. 1;
FIG. 3 is a fragmentary bottom plan view taken along the line 3--3 of FIG. 2;
FIG. 4 is a perspective view of a preferred embodiment of the invention equipped with skids for winter use;
FIG. 5 is a fragmentary exploded view in perspective showing the means for fastening the collapsible barrier to the foot board;
FIG. 6 is a detailed elevational view, partly in fragmentary section, showing the means for securing the steering and stabilizing handles to the collapsible barrier;
FIG. 7 is a fragmentary side elevational view taken along the line 7--7 of FIG. 4;
FIG. 8 is a fragmentary bottom plan view taken along the line 8--8 of FIG. 7;
FIG. 9 is a perspective view of the claw shown in FIGS. 7 and 8;
FIG. 10 is a side elevational view of a preferred embodiment of a skid for use in retrofitting the device for snow surface use; and
FIG. 11 is a top plan view of the skid shown in FIG. 10.
DETAILED DESCRIPTION OF THE INVENTION
Reference is first made to FIG. 1, which illustrates a preferred embodiment of the invention adapted for summer use. The invention 10 is essentially comprised of two major components,--the collapsible impact barrier 12, and the chassis 14. The barrier 12, in turn, is comprised of a top wooden shelf 16, a middle shelf 18 and a bottom shelf 20. The shelves are approximately each 14" square and approximately 1" thick. Slats 22, are secured to each of the side and front edges of the shelves and fastened to each shelf edge with two 1" No. 8 wood screws. No other means are utilized to secure the slats to the shelves, such as glue, braces or other threaded fasteners. Thus, an impact received by either the top shelf 16 or middle shelf 18 will cause a twisting tearing action between the shelves, screws and slats. The barrier will yield to the impact and consume energy.
The chassis 14 comprises a foot board 24 to which skateboard wheel mounts 26, hereinafter called "trucks", and wheels 28 are mounted to the foot board's underside. A brake board 30 is pivotally secured to the rear portion of the footboard 24 by pivot rod means 32. As best shown in FIG. 5, barrier 12 is secured to footboard 24 by a pair of 1/2" carriage bolts 34 which pass through holes in bottom shelf 20, and footboard 24 and are secured to the underside of footboard 24 by nuts 36 and washers 38. Referring to FIG. 6, threaded studs 23 in handles 25 are fitted in holes 27 of slats 1 and 9 and are secured thereto by washers 29 and nuts 31.
Referring now to FIGS. 2 and 3, therein is shown the brake means for summer use. A pair of skate wheels 28 are mounted on axle 40 which is secured in axle truck 26. Truck 26 is fastened to the underside of footboard 24 by threaded fasteners 42. Brakeboard 30 is biased upwardly about pivot rod 32 by leaf spring 44 which has an inboard end 46 secured between truck 26 and footboard 24. An outboard end 48 of leaf spring 44 is positioned to make sliding engagement with a pressure plate 50, secured to the underside of brakeboard 30 by threaded fasteners, an adhesive or any other suitable means. The upward bias of brakeboard 30 is delimited by detent plates 52, FIG. 3, secured to the underside of brakeboard 30 by threaded fasteners. Brake pads 54 are secured to the underside of brakeboard 30 and positioned to make pressure engagement with wheels 28 when the brakeboard 30 is depressed.
FIGS. 4 through 9 illustrate the device 10 retrofitted with skids for winter use. As shown generally in FIG. 4, the wheels 28 have been removed from the trucks 26 and have been replaced by skids 60. Also, a claw brake 62, FIGS. 7-9, is secured over pressure plate 50 with threaded fasteners 64 on the underside of brakeboard 30. The claw brake 62 includes a pair of claws 66 having chisel edges 68 between the skids 60 adapted to dig into ice and snow to slow or arrest forward movement of the device.
Reference is now made to the skid 60, per se, shown in FIGS. 10 and 11. This skid is preferably made of molded plastic, such as a compound of polyurethane, and comprises a runner 70 and a mounting boss 72. The head 74 of the runner 70 is curved upwardly to negotiate surface irregularities encountered when the device is in use. The tail 76 is also slightly curved upward to facilitate sideslipping of the runner 70 on the surface during turning. A transverse axle hole 78 is provided in mounting boss 72 adapted to receive the axle 40 therethrough. The same nuts 80 and washers 82 used to secure wheels 28 to truck axles 40 may be reused to secure skids 60 to these same axles 40.
Although preferred embodiments of the subject invention have been shown and described, it will be appreciated by those skilled in the art that additional embodiments, modifications and improvements can be readily anticipated by those skilled in the art based on a reading and study of the present disclosure. Such additional embodiments, modifications and improvements may be fairly presumed to be within the spirit, scope and purview of the invention as defined by the subtended claims.
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A child's foot-assisted scooterlike locomotion device is provided which is adapted for use with wheels on improved hard surfaces and for use with skids for use on snow-covered surfaces. Turning of the device is accomplished, irrespective of whether the device is equipped with wheels or skids, by a shift of weight on the device in the direction in which turning is to occur.
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PRIORITY CLAIM
This application is a continuation of, claims priority to and the benefit of U.S. patent application Ser. No. 12/372,595, filed on Feb. 17, 2009, which is a continuation-in-part, claims priority to and the benefit of U.S. patent application Ser. No. 11/865,581, filed on Oct. 1, 2007, and issued as U.S. Pat. No. 8,125,459, the entire contents of which are incorporated by reference herein.
BACKGROUND OF THE INVENTION
Numerous devices incorporate touchscreens as both a display and an input device. Touchscreens are widely used in environments and form factors where a simple and dynamic interface is preferred.
Although touchscreens are widely used in gaming devices, for example, currently available touchscreens have limitations in detecting the increasing variety of inputs that the graphic user interfaces and applications make possible.
SUMMARY OF THE INVENTION
A composite touchscreen incorporates acoustic pulse recognition sensing and capacitive sensing technology. The hybrid screen incorporates the advantages of each technology while minimizing the drawbacks. When such a screen is incorporated in a gaming device specialized gestures and functions can be implemented that enhance the interface, the range of games, and the gaming experience.
One embodiment relates to a gaming system. The gaming system comprises a memory device, a microprocessor, and a composite touchscreen. The composite touchscreen comprises a display, an acoustic pulse recognition touchscreen subsystem, a capacitive touchscreen subsystem, and one or more touchscreen controllers. The touchscreen is configured to detect an x-y coordinate location of a touch upon the touchscreen with the acoustic pulse recognition subsystem and to detect a lift-off of an object with the capacitive touchscreen subsystem.
According to a further aspect of the embodiment, the gaming system is configured to access a database of touchscreen input data stored in the memory device of the system, and map a plurality of detected inputs at the composite touchscreen to one or more gestures, a first of the plurality of inputs comprising a lift-off of an object detected with the capacitive touchscreen subsystem and a second of the plurality of inputs comprising a touch of the composite touchscreen detected with the acoustic pulse recognition touchscreen subsystem.
Another embodiment relates to a gaming device, comprising a microprocessor, a memory device, and a touchscreen. The touchscreen comprises a transparent substrate, a plurality of acoustic pulse sensors disposed upon a first surface of the transparent substrate and configured to detect an acoustic wave generated by an object making contact with the substrate or a layer in contact with the substrate. The touchscreen further comprises a capacitive plate comprising a transparent conductive layer disposed upon a second surface of the transparent substrate, an insulating layer disposed upon a surface of the capacitive plate, and control circuitry configured to detect an x-y coordinate location of a touch by measuring an output of each of the plurality of acoustic pulse sensors, and to detect a lift-off of an object in contact with the capacitive plate or a layer disposed upon the plate.
Yet another embodiment relates to a method of operating a gaming machine. The method comprises establishing a first logical region of a touchscreen display, establishing a second logical region of a touchscreen display, detecting a touch within the first logical region with an acoustic pulse recognition portion of a touchscreen display, detecting a lift off of an object within the second logical region with a capacitive portion of the touchscreen display, and causing a change in the display within the first logical region when the lift off is detected in the second logical region.
A further understanding of the nature and advantages of the present invention may be realized by reference to the remaining portions of the specification and the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of some components of gaming system 100 , according to an embodiment of the invention.
FIG. 2 is a side view or cross section of some components of composite touchscreen 200 .
FIG. 3 is a flowchart illustrating a method of detection utilizing a composite touchscreen, according to an embodiment of the invention.
FIG. 4 is a block diagram illustrating touchscreen and processing componentry.
FIG. 5 is a flowchart illustrating input analysis, according to an embodiment of the invention.
FIG. 6 is a flowchart illustrating gesture analysis, according to an embodiment of the invention.
FIG. 7 illustrates an exemplary gesture that may be detected with the composite touchscreen 200 and/or gaming system 100 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in detail to specific embodiments of the invention including the best modes contemplated by the inventors for carrying out the invention. Examples of these specific embodiments are illustrated in the accompanying drawings. While the invention is described in conjunction with these specific embodiments, it will be understood that it is not intended to limit the invention to the described embodiments. On the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims. In the following description, specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be practiced without some or all of these specific details. In addition, well known features may not have been described in detail to avoid unnecessarily obscuring the invention.
FIG. 1 shows a block diagram of an example embodiment of a portion of an electronic gaming system 100 .
As illustrated in the example embodiment of FIG. 1 electronic gaming system 100 may include at least one processor 156 configured to execute instructions and to carry out operations associated with the gaming system 100 . For example, using instructions retrieved from memory, the processor(s) 156 may control the reception and manipulation of input and output data between components of the computing system 100 . The processor(s) 156 may be implemented on a single-chip, multiple chips or multiple electrical components.
In at least one embodiment, the processor(s) 156 together with an operating system operates to execute code (such as, for example, game code) and produce and use data. A least a portion of the operating system, code and/or data may reside within a memory storage device 158 that may be operatively coupled to the processor(s) 156 . Memory storage device 158 may be configured or designed to store code, data, and/or other types of information that may be used by the electronic gaming system 100 . Memory storage device 158 is preferably a non-volatile mass storage device such as magnetic hard drive, Flash memory, NVRAM EEPROM, or other media.
The gaming system 100 may also include at least one display device 168 that may be operatively coupled to the processor(s) 156 . In at least one embodiment, one or more display device(s) may include at least one flat display screen incorporating flat-panel display technology. This may include, for example, a liquid crystal display (LCD), a transparent light emitting diode (LED) display, an electroluminescent display (ELD), and a microelectromechanical device (MEM) display, such as a digital micromirror device (DMD) display or a grating light valve (GLV) display, etc. In some embodiments, one or more of the display screens may utilize organic display technologies such as, for example, an organic electroluminescent (OEL) display, an organic light emitting diode (OLED) display, a transparent organic light emitting diode (TOLED) display, a light emitting polymer display, etc. Any of these underlying display technologies may be incorporated into a touchscreen.
One or more of the display device(s) 168 may be generally configured to display a graphical user interface (GUI) 169 that provides an easy to use interface between a user of the gaming system and the operating system (and/or application(s) running thereon).
According to various embodiments, the GUI 169 may represent programs, interface(s), files and/or operational options with graphical images, objects, and/or vector representations. The graphical images may include windows, fields, dialog boxes, menus, icons, buttons, cursors, scroll bars, etc. Such images may be arranged in predefined layouts, and/or may be created dynamically to serve the specific actions of one or more users interacting with the display(s).
During operation, a user may select and/or activate various graphical images in order to initiate functions and/or tasks associated therewith. The GUI 169 may additionally and/or alternatively display information, such as non interactive text and/or graphics.
The gaming system 100 may also include one or more input device(s) 170 that may be operatively coupled to the processor(s) 156 . The input device(s) 170 may for example be used to perform tracking and/or to make selections with respect to the GUI(s) 169 on one or more of the display(s) 168 . The input device(s) 170 may also be used to issue commands at the electronic gaming system 2100 .
FIG. 2 illustrates a cross section of a composite touchscreen 200 in accordance with an embodiment of the invention. The composite touchscreen 200 comprises an acoustic pulse recognition (“APR”) system 207 which comprises APR transducers 208 A, 208 B, 208 C, and 208 D ( 208 C and D not shown in the cross section) etc. At least four transducers 208 A-D are preferably present to detect the placement of a touch with sufficient precision, as will be discussed in greater detail below and with regard to FIGS. 3-4 .
The top layer is provided as a silicon dioxide (SiO2) layer 202 which can serve as an insulating layer and a protection layer for the capacitive touchscreen layer/element 204 . The capacitive touchscreen layer/element may be either of a surface capacitive technology or a projected capacitive technology. In an embodiment where the touchscreen element 204 is of a surface capacitive nature, it comprises a uniform conductive coating on a glass panel. Electrodes around the panel's edge evenly distribute a low voltage across the conductive layer, creating a uniform electric field. A touch draws current from each corner. The controller measures the ratio of the current flow from the corners and calculates the touch location. Inversely, the lift off of the touch or resting item can be detected when the current draw ceases.
The uniform conductive layer comprises, for example, an indium tin oxide (ITO) layer. This capacitive layer can detect a touch of an object such as a finger, and a drag of an object, as well as lift off of an object, as mentioned above. While capacitive touchscreens are widely used and have many advantages, a capacitive touchscreen, used by itself, is not ideal in locating the touches of multiple objects that occur at or near the same time. Layer 204 can also be used to transmit an RF field, and in one embodiment the composite touchscreen 200 may also be used to identify the source of a touch with radio frequency identification (“RFID”) using the layer 204 as an RFID antenna. The bottom layer is depicted as a glass substrate (layer) 206 . The glass substrate 206 can provide the structural strength for the composite touchscreen. Beneath the glass substrate is the underlying display (not shown) of the touchscreen.
A touch at each position on the glass generates a unique sound. The impact when the screen is touched, or the friction caused while dragging between a user's finger or stylus and the glass, creates an acoustic wave. The wave radiates away from the touch point, making its way to the transducers. The four transducers, 208 A-D, attached to the edges of the touchscreen glass pick up the sound of the touch. In one embodiment, the sound is then digitized by the controller 310 A/B or processor 156 and compared to a list of prerecorded sounds for every position on the glass. The cursor position is instantly updated to the touch location. The APR system is designed to ignore extraneous and ambient sounds, as they do not match a stored sound profile.
APR differs from other attempts to recognize the position of touch with transducers or microphones, as it uses a simple table lookup method rather than requiring powerful and expensive signal processing hardware to attempt to calculate the touch location without any references.
In an embodiment where the capacitive element 204 utilizes projected capacitive technology, a sensor grid of micro-fine wires, may be laminated between two protective layers. The protective layers may be the SiO2 layer 202 and glass substrate 206 , or may alternatively be two additional protective layers (not shown).
The composite touchscreen 200 has many advantages over prior commercially available touchscreens.
Resistive touchscreens have been the most popular technology used in retail, restaurant, and other applications, in spite of having an outer plastic layer that degrades the optics and can wear out over time. This is because it allows a user to touch the display with a pen, credit card, or ID card or to be able to touch small boxes along the bottom edge of the display where only a fingernail or pen will make contact.
In addition to the optical qualities and resistance to wear of glass, as with surface wave, APR technology can be activated with a finger, fingernail, pen or stylus, or credit card, as with resistive technology.
For some applications such as gaming, a primary issue is not optics, durability, or stylus choice, but contaminant resistance. Here resistive and capacitive technologies have had the edge, as they continue to work with liquids and other contaminants on the screen, and they can be easily sealed.
APR technology is resistant to contaminants on the screen such as liquids, dirt, ketchup, grease, and ultrasound gels, and it even works with scratches. It can also be sealed watertight to industrial standards, has the optical qualities of glass and like glass is resistant to cleaning and sterilizing chemicals, and can be activated with fingers or other various items.
APR does not miss touches of short duration as some other technologies do, because a short tap also generates a recognizable sound. Most touch applications are simple “touch-and-go,” designed for public users or employees with little training. Capacitive is normally the best technology for dragging, but APR recognizes a quick tap and handles dragging very well, like capacitive.
APR technology is also distinguished from other surface acoustic wave (“SAW”) technology. A non-APR surface acoustic wave touchscreen comprises a glass overlay with transmitting and receiving piezoelectric transducers for the X and Y axes. The controller sends an electrical signal to the transmitting transducer, which converts the signal into ultrasonic waves within the surface of a glass layer. These waves are directed across the touchscreen by an array of reflectors. Reflectors on the opposite side gather and direct the waves to the receiving transducer, which reconverts them into an electrical signal. The process is repeated for each axis. A touch absorbs a portion of the waves traveling across it. The received signals for X and Y are compared to the stored digital maps, the change recognized, and a coordinate calculated.
Although, a preferred embodiment of composite touchscreen 200 utilizes APR technology with capacitive technology, in another embodiment the capacitive technology is used in conjunction with surface acoustic wave technology previously described rather than with APR technology. The APR touchscreen may in alternative embodiments of a composite touchscreen be combined with a resistive touchscreen.
Touch-and-hold or drag-and-hold are currently not possible with APR technology alone, as no sounds are emitted in the hold position. Additionally, the lift-off of a hold or object is also not reliably detectable with APR technology alone.
FIG. 3 illustrates an overview of sensing using composite touchscreen 200 and system 100 . In step 302 , a touch is detected with the APR functionality and elements of screen 200 . Then in step 304 , the lift off of an object is detected with a capacitance measurement using the capacitive functionality and elements of screen 200 . A drag operation may be sensed by either the APR or capacitive functionality or a combination of the two.
FIG. 4 illustrates a block diagram of some components of composite touchscreen 200 and system 100 . APR touchscreen element(s) 306 , which comprise at least the APR transducers 508 A-D and may also be said to comprise the glass substrate 206 and protective SiO2 layer 20 , are electrically coupled to APR touchscreen controller 310 A. Capacitive touchscreen element(s) 308 are electrically coupled to capacitive touchscreen controller 310 B. Capacitive touchscreen elements comprise the capacitive touchscreen layer 204 and the associated circuitry including the electrodes around the layer's edge. Controller 310 A and 310 B may be discrete devices or may be a single controller with both APR and capacitive touchscreen control functionality. The controllers comprise processing and control circuitry as well as memory for storing logic to operate the composite screen. Controllers 310 A and 310 B are coupled to a system level processor 156 via communications link(s) 314 which may comprise multiple discrete links or may alternatively comprise a serial connection with both data to/from APR controller 310 A and capacitive controller 310 B.
FIG. 5 shows an example embodiment of input analysis and FIG. 6 shows an example embodiment of gesture analysis that may be implemented by one or more systems, devices, and/or components of an electronic gaming system.
Referring first to FIG. 5 , as the various different players at a gaming system interact with the gaming system's display, the gaming system may detect ( 452 ) various types of input data. For example, according to different embodiments, the input data may be represented by one or more images (e.g., captured using one or more different types of sensors). For example, in a preferred embodiment a touch is detected by the APR system and the lift-off of an item (e.g. hand) is detected by the capacitive touchscreen components using a composite touchscreen.
At 454 , the input data may be processed. In at least one embodiment, at least a portion of the input data may be processed by the gaming controller of the gaming system. In some embodiments, separate processors and/or processing systems may be provided at the gaming system for processing all or specific portions of the input data. For example, the input data may be processed by touchscreen controllers 310 A and/or 310 B, alone or in combination with processor 156 .
In at least one embodiment, the processing of the input data may include identifying ( 456 ) the various contact region(s) and/or chords associated with the processed input data. Generally speaking, when objects are placed near or on a touch sensing surface, one or more regions of contact (sometimes referred to as “contact patches”) may be created and these contact regions form a pattern that can be identified. The pattern can be made with any assortment of objects and/or portions of one or more hands such as finger, thumb, palm, knuckles, etc.
At 460 , various associations may be created between or among the different identified contact regions to thereby enable the identified contact regions to be separated into different groupings in accordance with their respective associations. For example, in at least one embodiment, the origination information may be used to identify or create different groupings of contact regions based on contact region-origination entity associations. In this way, each of the resulting groups of contact region(s) which are identified/created may be associated with the same origination entity as the other contact regions in that group.
It is anticipated that, in at least some embodiments, a complex gesture may permit or require participation by two or more users. As mentioned earlier, a composite touchscreen facilitates the recognition of multiple contemporaneous or simultaneous touches. For example, in one embodiment, a complex gesture for manipulating an object displayed at an interactive display surface may involve the participation of two or more different users simultaneously or concurrently interacting with that displayed object (e.g., wherein each user's interaction is implemented via a gesture performed at or over a respective region of the display object). Accordingly, in at least some embodiments, the gaming system may be operable to process the input data resulting from a multi-user combination gesture, and to identify and/or create associations between different identified groupings of contact regions. For example, where two or more different users at the gaming system are simultaneously or concurrently interacting with a displayed object, the identified individual contact regions may be grouped together according to their common contact region-origination entity associations, and the identified groups of contact regions may be associated or grouped together based on their identified common associations (if any).
As shown at 462 , one or more separate (and/or concurrent) threads of a gesture analysis procedure may be initiated for each (or selected) group(s) of associated contact region(s).
In the example of FIG. 6 , it is assumed that a separate instance or thread of gesture analysis has been initiated (e.g., during input analysis) for processing a gesture involving an identified grouping of one or more contact region(s) which has been performed by a user.
As shown at 401 , it is assumed that various types of input parameters/data may be provided to the gesture analysis procedure for processing. Examples of various types of input data which may be provided to the gesture analysis procedure may include, but are not limited to, one or more of the following (or combinations thereof):
identified groupings of contact region(s); origination information (e.g., contact region-origination entity associations, touch-ownership associations, etc.); origination entity identifier information; information useful for determining an identity of the player/person performing the gesture; association(s) between different identified groups of contact regions; number/quantity of contact regions; shapes/sizes of regions; coordination location(s) of contact region(s) (which, for example, may be expressed as a function of time and/or location); arrangement of contact region(s) raw movement data (e.g., data relating to movements or locations of one or more identified contact region(s), which, for example, may be expressed as a function of time and/or location); movement characteristics of gesture (and/or portions thereof) such as, for example, velocity, displacement, acceleration, rotation, orientation, etc.; timestamp information (e.g., gesture start time, gesture end time, overall duration, duration of discrete portions of gesture, etc.) game state information; gaming system state information; starting point of gesture; ending point of gesture; number of discrete acts involved with gesture; types of discrete acts involved with gesture; order of sequence of the discrete acts; contact/non-contact based gesture; initial point of contact of gesture; ending point of contact of gesture; current state of game play (e.g., which existed at the time when gesture detected); game type of game being played at gaming system (e.g., as of the time when the gesture was detected); game theme of game being played at gaming system (e.g., as of the time when the gesture was detected); current activity being performed by user (e.g., as of the time when the gesture was detected);
For further information on gesture recognition, please refer to U.S. patent application Ser. No. 12/265,627 entitled “Intelligent Multiplayer Gaming System With Multi-Touch Display” to Wells et al., which is hereby incorporated by this reference in the entirety. In at least some embodiments, at least some of the example input data described above may be determined during processing of the input data at 404 .
At 402 , an identity of the origination entity (e.g., identity of the user who performed the gesture) may optionally be determined. In at least one embodiment, such information may be subsequently used for performing user-specific gesture interpretation/analysis, for example, based on known characteristics relating to that specific user. In some embodiments, the determination of the user/originator identity may be performed at a subsequent stage.
At 404 , the received input data portions(s) may be processed, along with other contemporaneous information, to determine, for example, various properties and/or characteristics associated with the input data such as, for example, one or more of the following (or combinations thereof):
Determining and/or recognizing various contact region characteristics such as, for example, one or more of the following (or combinations thereof): number/quantity of contact regions; shapes/sizes of regions; coordination location(s) of contact region(s) (which, for example, may be expressed as a function of time and/or location); arrangement(s) of contact region(s); Determining and/or recognizing association(s) between different identified groups of contact regions; Determining and/or recognizing raw movement data such as, for example: data relating to movements or locations of one or more identified contact region(s), which, for example, may be expressed as a function of time and/or location; Determining information useful for determining an identity of the player/person performing the gesture; Determining and/or recognizing movement characteristics of the gesture (and/or portions thereof) such as, for example: velocity, displacement, acceleration, rotation, orientation, etc.; Determining and/or recognizing various types of gesture specific characteristics such as, for example, one or more of the following (or combinations thereof): starting point of gesture; ending point of gesture; starting time of gesture; ending time of gesture; duration of gesture (and/or portions thereof); number of discrete acts involved with gesture; types of discrete acts involved with gesture; order of sequence of the discrete acts; contact/non-contact based gesture; initial point of contact of gesture; ending point of contact of gesture; etc. Determining and/or accessing other types of information which may be contextually relevant for gesture interpretation and/or gesture-function mapping, such as, for example, one or more of the following (or combinations thereof): game state information; gaming system state information; current state of game play (e.g., which existed at the time when gesture detected); game type of game being played at gaming system (e.g., as of the time when the gesture was detected); game theme of game being played at gaming system (e.g., as of the time when the gesture was detected); number of persons present at the gaming system; number of persons concurrently interacting with the interacting with the multi-touch, multi-player interactive display surface (e.g., as of the time when the gesture was detected); current activity being performed by user (e.g., as of the time when the gesture was detected); number of active players participating in current game; amount or value of user's wagering assets;
In at least one embodiment, the processing of the input data at 404 may also include application of various filtering techniques and/or fusion of data from multiple detection or sensing components of the gaming system.
At 408 , the processed raw movement data portion(s) may be mapped to a gesture. According to specific embodiments, the mapping of movement data to a gesture may include, for example, accessing ( 408 ) a user settings database, which, for example, may include user data (e.g., 409 ). According to specific embodiments, such user data may include, for example, one or more of the following (or combination thereof): user precision and/or noise characteristics/thresholds; user-created gestures; user identity data and/or other user-specific data or information. According to specific embodiments, the user data 409 may be used to facilitate customization of various types of gestures according to different, customized user profiles.
Additionally, in at least some embodiments, mapping of the actual motion to a gesture may also include accessing a gesture database (e.g., 412 ). For example, in one embodiment, the gesture database 412 may include data which characterizes a plurality of different gestures recognizable by the electronic gaming system for mapping the raw movement data to a specific gesture (or specific gesture profile) of the gesture database. In at least one embodiment, at least some of the gestures of the gesture database may each be defined by a series, sequence and/or pattern of discrete acts. In one embodiment, the raw movement data may be matched to a pattern of discrete acts corresponding to of one of the gestures of the gesture database.
It will be appreciated that, it may be difficult for a user to precisely duplicate the same raw movements for one or more gestures each time those gestures are to be used as input. Accordingly, particular embodiments may be operable to allow for varying levels of precision in gesture input. Precision describes how accurately a gesture must be executed in order to constitute a match to a gesture recognized by the electronic gaming system, such as a gesture included in a gesture database accessed by the electronic gaming system. According to specific embodiments, the closer a user generated motion must match a gesture in a gesture database, the harder it will be to successfully execute such gesture motion. In particular embodiments movements may be matched to gestures of a gesture database by matching (or approximately matching) a detected series, sequence and/or pattern of raw movements to those of the gestures of the gesture database.
For example, as the precision of gestures required for recognition increases, one may have more gestures (at the same level of complexity) that may be distinctly recognized. In particular embodiments, the precision required by electronic gaming system for gesture input may be varied. Different levels of precision may be required based upon different conditions, events and/or other criteria such as, for example, different users, different regions of the “gesture space” (e.g., similar gestures may need more precise execution for recognition while gestures that are very unique may not need as much precision in execution), different individual gestures, such as signatures, and different functions mapped to certain gestures (e.g., more critical functions may require greater precision for their respective gesture inputs to be recognized), etc. In some embodiments users and/or casino operators may be able to set the level(s) of precision required for some or all gestures or gestures of one or more gesture spaces.
According to specific embodiments, gestures may be recognized by detecting a series, sequence and/or pattern of raw movements performed by a user according to an intended gesture. In at least one embodiment, recognition may occur when the series, sequence and/or pattern of raw movements is/are matched by the electronic gaming system (and/or other system or device) to a gesture of a gesture database.
At 414 , the gesture may be mapped to one or more operations, input instructions, and/or tasks (herein collectively referred to as “functions”). According to at least one embodiment, this may include accessing a function mapping database (e.g., 416 ) which, for example, may include correlation information between gestures and functions.
In at least one embodiment, different types of external variables (e.g., context information 418 ) may affect the mappings of gestures to the appropriate functions. Thus, for example, in at least one embodiment, function mapping database 416 may include specific mapping instructions, characteristics, functions and/or any other input information which may be applicable for mapping a particular gesture to appropriate mapable features (e.g., functions, operations, input instructions, tasks, keystrokes, etc) using at least a portion of the external variable or context information associated with the gesture. Additionally, in at least some embodiments, different users may have different mappings of gestures to functions and different user-created functions.
For example, according to specific embodiments, various types of context information (and/or criteria) may be used in determining the mapping of a particular gesture to one or more mapable features or functions. Examples of such context information may include, but are not limited to, one or more of the following (or combinations thereof):
game state information (e.g., current state of game play at the time when gesture performed); criteria relating to game play rules/regulations (e.g., relating to the game currently being played by the user); criteria relating to wagering rules/regulations; game type information (e.g., of game being played at electronic gaming system at the time when gesture performed); game theme information (e.g., of game being played at electronic gaming system at the time when gesture performed); wager-related paytable information (e.g., relating to the game currently being played by the user); wager-related denomination information (e.g., relating to the game currently being played by the user); user identity information (e.g., 411 ), which, for example, may include information relating to an identity of the player/person performing the gesture; time/date information; location(s) of the region(s) of contact at (or over) the multi-touch, multi-player interactive display surface of the gesture; content displayed at the multi-touch, multi-player interactive display (e.g., at the time when gesture performed); user/player preferences; device state information (e.g., 421 ); etc.
Thus, for example, in at least one embodiment, a first identified gesture may be mapped to a first set of functions (which, for example, may include one or more specific features or functions) if the gesture was performed during play of a first game type (e.g., Blackjack) at the electronic gaming system; whereas the first identified gesture may be mapped to a second set of functions if the gesture was performed during play of a second game type (e.g., Sic Bo) at the electronic gaming system.
At 422 one or more associations may be created between the identified function(s) and the user who has been identified as the originator of the identified gesture. In at least one embodiment, such associations may be used, for example, for creating a causal association between the initiation of one or more functions at the gaming system and the input instructions provided by the user (via interpretation of the user's gesture).
As shown at 424 , the electronic gaming system may initiate the appropriate mapable set of features or functions which have been mapped to the identified gesture. For example, in at least one embodiment, an identified gesture may be mapped to a specific set of functions which are associated with a particular player input instruction (e.g., “STAND”) to be processed and executed during play of a blackjack gaming session conducted at the electronic gaming system.
FIG. 7 illustrates an example of card game related gesture-function mapping information in order to illustrate gesture recognition using a composite touchscreen display
As illustrated in the example embodiment of FIG. 7 , an example gesture graphically represented (e.g., at 710 a ) and described which, for example, may be mapped to function(s) (e.g., user input/instructions) corresponding to: PEEK AT CARD(S). For example, in at least one embodiment, a user may convey the input/instruction(s) PEEK AT CARD(S) for example, by concurrently performing multiple different movements and/or gestures (e.g., as illustrated at 710 a ) at a touchscreen interface of the gaming system. As illustrated in the example embodiment of FIG. 7 , combination gesture 710 a may be defined to include at least the following gesture-specific characteristics: multiple concurrent gestures: side of one hand (e.g., 703 ) placed in contact with surface adjacent to desired card(s) image (e.g., 707 ); single region of contact (e.g., 705 ) on or above corner of card(s), continuous drag towards center of card(s) image concurrently while side of one hand remains in contact with surface. In at least one embodiment, a user may be required to use both hands to perform this combination gesture. The placement of the side of one hand may be sensed with the APR system whereas lift-off of the hand would then be sensed by capacitive measurement with capacitive touchscreen element. Placement, prolonged placement, or resting of the object is something that is longer than a touch. When the lift-off of the hand ( 703 ) is sensed, in certain games such as Texas hold-em, the players cards would automatically be hidden, so that when the shielding provided by the hand is removed, players cannot see the cards of others. In one embodiment this occurs without any further actions or gestures required by the user.
As illustrated in the example embodiment of FIG. 7 , as the user performs this gesture and continues to slide or drag his finger over the card(s) image (e.g., as represented at 713 ), the image of the card(s) 707 may automatically and dynamically be updated to reveal a portion (e.g., 707 a ) of one or more of the card face(s) to the user. In at least one embodiment, use of the covering hand (e.g., 703 ) may be required to help obscure visibility of the displayed portion ( 707 a ) of card face(s) by other players at the gaming table. Different logical regions may be established within areas of the display that are monitored for certain actions. For example, a first logical region may be established at or near the area of the image of the card(s) 707 whereas another logical region may be established at or near where the hand 703 is expected.
As mentioned above, in at least one embodiment, the image of the card(s) 707 may automatically and dynamically be updated to remove the displayed portion ( 707 a ) of the card face(s), for example, in response to detecting a non-compliant condition of the gesture, such as, for example, the removal of the covering hand 703 and/or sliding digit.
As illustrated in the example embodiment of FIG. 7 , the electronic gaming system may be configured or designed to recognize and/or identify one or more different patterns and/or arrangements of concurrent contact regions (e.g., 703 a ) as being representative of (and/or as corresponding to) a side of a human hand (e.g., in one or more configurations) being placed in contact with the multi-touch input interface.
Gesture 710 b represents an alternative example gesture combination which, for example, may be mapped to function(s) (e.g., user input/instructions) corresponding to: PEEK AT CARD(S). In at least one embodiment, this combination gesture may be performed in a manner similar to that of gesture 710 a , except that, as shown at 710 b , the user may initiate the gesture at a different corner (e.g., 705 b ) of the card(s) to cause a different portion or region (e.g., 707 b ) of the card(s) to be revealed.
While the invention has been particularly shown and described with reference to specific embodiments thereof, it will be understood by those skilled in the art that changes in the form and details of the disclosed embodiments may be made without departing from the spirit or scope of the invention.
In addition, although various advantages, aspects, and objects of the present invention have been discussed herein with reference to various embodiments, it will be understood that the scope of the invention should not be limited by reference to such advantages, aspects, and objects. Rather, the scope of the invention should be determined with reference to the appended claims.
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A composite touchscreen incorporates acoustic pulse recognition sensing and capacitive sensing technology. The hybrid screen incorporates the advantages of each technology while minimizing the drawbacks. When such a screen is incorporated in a gaming device specialized gestures and functions can be implemented that enhance the interface, the range of games, and the gaming experience.
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FIELD OF THE INVENTION
This invention relates to fluid production wells. More particularly, it relates to fluid production wells which employ gravel packs to prevent the production of sand in conjunction with well fluids.
BACKGROUND OF THE INVENTION
The inclusion of sand with the well fluids produced from an unconsolidated subterranean oil or gas producing zone has long been a problem in the petroleum industry. It can cause erosion of production equipment and can plug the well, causing reduced production levels or loss of well production entirely.
An effective means of combating the problem is the gravel pack, which involves placing a tubular liner in the well bore and packing gravel around it. The liner has slots or other apertures in its walls which are smaller in size than the gravel particles so as to permit the flow of formation fluids while preventing entry of the particles. Typically, the gravel particles are designed to be of a size that will exclude median formation grain size. Thus the gravel pack and screen are designed for absolute exclusion of formation particles and gravel particles from the liner.
In addition, modern methods of predicting gravel size requirements have resulting in reduced gravel pack damage caused by formation particle invasion. Despite improved gravel pack technology, however, damaged gravel packs continue to be a problem. Even with proper gravel sizing, any porosity fluctuation resulting from fluidization with an associated change in the steady rate of fluid flow may cause formation particle release or failure of the formation with its subsequent flow into any open porosity or void in the perforations or annulus. Complete failure of the gravel pack may occur when a pressure surge causes movement of the gravel up the lap area, thereby exposing the liner directly to sand particles, which it is not designed to retain. The lap area in this case is the annular space between the top of the gravel pack and the packer through which the production tubing extends.
The most common cause of severe pressure surges is the shut-in of a well. Normally, when production commences after a gravel pack has been installed the pressure inside the liner will decrease due to the various pressure drops encountered by the fluid as it flows through the well. As a result, fluid will flow down from the lap area through the gravel pack and into the liner to equalize the pressure. When the well is shut in, however, the well bore pressure builds up to essentially the reservoir pressure and, for the pressure of the lap area to equalize to the reservoir pressure, fluid flow will occur from the formation up the gravel pack and into the lap area. If the pressure build-up is too rapid, the fluid velocity up the lap area can be great enough to mobilize or fluidize the gravel. It should be understood that the use of either term "mobilize" or "fluidize" in the specification and claims is not intended to be restricted to any particular type of gravel movement but to pertain to flowable movement in general, including movement as a result of the particles being suspended in a carrier medium.
The significance of the problem can be placed in perspective when it is realized that wells are shut in many times each year, some due to operating requirements but many more due to being instantaneously shut in by emergency shut-down systems, which become operative in response to pressure fluctuations or facility upsets or to adverse weather conditions. When such wells are returned to production, a decrease in productivity may occur, possibly even to the extent of completely losing production, due to sanding-up of the well.
It has been suggested that by determining the minimum velocity required to cause fluidization of a gravel bed, the minimum shut-in time which produces this velocity can be calculated. Then, by taking steps to ensure that the shut-in process is longer in duration than the calculated minimum shut-in time, fluidization can be prevented. As a practical matter the implementation of such a shut-in process is not only time consuming but is not possible in the many emergency instantaneous shut-in situations referred to above.
It has also been suggested that a consolidated gravel pack capable of withstanding severe pressure surges and fluid velocities without fluidizing the gravel be employed to solve this problem. Consolidated gravel packs can be implemented by utilizing gravel which has been coated with uncured resin or by incorporating a liquid resin system in a normal gravel pack slurry. Consolidated gravel packs have the advantage of permitting rapid shut-in, but are significantly more expensive than ordinary gravel packs. Further, consolidation systems have the disadvantage of lower permeability and porosity and possible formation damage due to coating failure when subsequent chemical stimulation is required. Air curing is also necessary in many cases to develop a high strength resin bond which will not fail. Curing the resin systems under in situ conditions can also result in a less competent resin coating.
It would be highly desirable to be able to prevent fluidization or mobilization of normal gravel packs without interfering with the action of emergency shut-down systems which cause instantaneous shut-in of a well. It would also be advantageous to be able to accomplish this in an economical and reliable manner.
BRIEF SUMMARY OF THE INVENTION
The invention has utility in fluid production wells and in steam, water or thermal injection wells. Basically, it comprises a well bore penetrating a subterranean producing zone, a tubing string extending through the well bore from the surface, gravel pack liner tubing connected to the tubing string, a gravel pack in the annulus between the gravel pack liner tubing and the well bore, and a packer which surrounds the tubing string at a point above the gravel pack. According to the invention, pressure relief valve means are provided in the tubing string at a location between the packer and the gravel pack, with the valve means being normally closed but adapted to open in response to increased fluid pressure in the gravel pack caused by a pressure surge such as that created with a well shut-in or rate change.
The pressure relief valve means preferably is one or more check valves biased in their closed position by a force less than the pressure which will cause the gravel pack to move or fluidize, e.g. by unloading, etc. When the valves open the differential pressure in the gravel pack is lessened, with the result that the pressure necessary to cause fluidization of the gravel pack is not reached.
The pressure relief valve means is located so that it does not interfere with normal operation of the well, including the introduction of gravel, the flow of well fluids and the movement of tools through the tubing. Although implementation of the invention is economical and relatively simple, the invention is highly effective in preventing movement of the gravel pack.
The features enabling the invention to function in the desired manner are brought out in more detail below in connection with the description of the preferred embodiment, wherein the above and other aspects of the invention, as well as other benefits, will readily be apparent.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic partial longitudinal sectional view of a typical well incorporating a gravel pack and the fluidization prevention means of the invention;
FIG. 2 is an enlarged partial transverse sectional view of the area of FIG. 1 enclosed in the circle 2, illustrating a valve which can be used in the invention, the valve being shown in closed condition;
FIG. 3 is an enlarged partial transverse sectional view similar to that of FIG. 2, but showing the valve in open condition;
FIG. 4 is a schematic partial longitudinal sectional view similar to that of FIG. 1, but showing the pressure relief action of the valve means of the invention during a period of increased pressure; and
FIG. 5 is a schematic partial longitudinal sectional view similar to that of FIG. 1, but showing the valve means of the invention during the step of gravel introduction.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, a portion of a typical subterranean oil or gas production well which penetrates a production formation 10 is illustrated in schematic form as comprising casing 12 cemented by a layer of cement 14 to the well bore 16. A tubing string 18 extends from the surface down to a point below packer 20, which surrounds the tubing string 18, at least partially supporting it and sealing the annulus between the tubing string and the casing. Although the details are not shown, it will be understood that the necessary equipment for operating the well located at the surface is in place. A shut-off valve 21 is shown in the fluid line 23 which when closed during production of the well will result in the well being shut in.
The tubing string 18 extends below the packer 20 into the upper end portion of blank pipe 22, which hangs from the packer 20 by conventional means well known in the art. The lower portion of the blank pipe 22 comprises a liner 24 which includes slits, wire wrapped screens or other form of apertures 26. Surrounding the liner 24 is a bed of gravel 28 supported on packer 30. Preferably, the gravel may also extend into production perforations 32 in the casing 12 and cement 14 through which production fluid from the surrounding formation 10 flows. The gravel may also extend into cavities in the formation surrounding the cement depending upon the structure of the formation 10.
The body of gravel resting on the packer 30 and terminating at its upper level 34 constitutes the gravel pack which functions in the normal manner to prevent the entry of sand particles into the gravel pack liner tubing 24. Located above the top of the gravel pack at a point in the blank pipe 22 below the packer 20 is pressure relief valve means 36. This valve means may be of any suitable design, as long as it is capable of remaining normally closed and functions to open upon the differential pressure across it reaching a predetermined level. Also, it is preferred that the design be such that wash-pipe or wireline tools can be freely moved through the passageway of the tubing 24 without obstruction by the valve means.
Referring to FIG. 2, the valve arrangement 36 comprises a threaded circular port 38 in the blank pipe 22 which receives a threaded sleeve 40. The sleeve includes an integral flange 42 which engages the external surface of the blank pipe 22 and which is sealed against the passage of fluids by suitable means, such as O-ring 44. The outer portion of the sleeve functions as a valve seat 46 for a valve element 48 which is normally urged into engagement with the valve seat by compression spring 50. The compression spring is supported at its opposite end by a cover or cap 52 having a cylindrical extension 54 engaged by threads 55 with the outer periphery of the flange 42. The cylindrical extension 54 is provided with a number of openings 56, and the cap 52 is provided with a centrally located opening 58 which functions as a bushing for receiving the valve stem 60.
In the operation of the valve, when the fluid pressure in the blank pipe 22 is greater than the force exerted by the spring 50, the fluid pressure will force the valve element 48 off the valve seat 46 against the force of the spring, with the valve stem moving out through the opening 58 to accommodate such action. The valve at this point would appear as illustrated in FIG. 3. It can be seen that fluid in the tubing 22 will now flow through the open valve seat and out the openings 56 as indicated by the flow arrows. This will continue until such time as the force of the spring is greater than the fluid pressure in the tubing 22, at which time the valve will again close. Obviously, although only two check valves have been shown in FIGS. 1, 2 and 3 for purpose of illustration, as many as necessary may be provided.
Still referring to FIGS. 2 and 3, circular screens 62 are provided in circular recesses or counterbores 64 surrounding the openings 56 of the cylindrical extension 54. By making the openings or mesh of the screen 62 less than the size of the particles in the gravel fluid, the valve will not be fouled by the gravel placement process. If desired, a screen 76 may also be provided at the valve inlet, such as in recess or counterbore 78 in sleeve 40, but this is not considered an essential element since normally no gravel would be present on the inside of the tubing to foul the valve.
Although the valve design of FIGS. 2 and 3 has been described in detail, it will be understood that other types of pressure relief valves could be used instead. For example, a ball and cage spring type check valve could be utilized to take advantage of the fact that the ball rotates and seats in many different positions, spreading the wear over a large area. This would be of special utility in abrasive service environments such as the one under discussion.
Referring back to FIG. 1, prior to beginning production after having placed the gravel pack 28, the fluid trapped in the lap area 66 after the packing has settled causes the pressure in the lap area 66 and in the gravel pack 28 to be substantially equal. Upon beginning production, the pressure in the gravel pack is reduced by reservoir and completion drawdown, which causes the higher pressure fluid in the lap area to be produced as the fluid pressures in the lap area and in the gravel pack seek to be equalized. The eventual substantially steady-state production operation is illustrated in FIG. 1, whereby production fluid flows up to the surface through the tubing 22 and 18 as indicated by the flow arrows 68. If the well is abruptly shut in by the closure of valve 21, the pressure in the gravel pack will increase to static reservoir pressure, creating a tendency for the fluid in the gravel pack to flow into the lap area in an attempt to equalize pressures within the well. When the pressure differential is sufficient and the pressure surge is rapid enough, fluidization or mobilization of the gravel pack, with all the attendant problems, occurs.
Fluidization upon well shut-in does not occur when the arrangement of the present invention is employed. Referring to FIG. 4, when the pressure of the fluid in the gravel pack increases to a critical predetermined point, the pressure in the fluid traveling up the blank pipe 22 will exceed the force exerted by the check valve springs 50 and will flow out the check valves into the lap area 66 as indicated by the flow arrows 70. This immediately increases the pressure in the lap area and minimizes fluid movement from the gravel pack to the lap area sufficiently to forestall gravel pack movement. Fluid will continue to flow through the check valves 36 into the lap area until the fluid pressures in the lap area and the gravel pack are equalized. Upon the well being placed back into production, the gravel pack will be intact at full productivity because small formation sand will not have mixed with the coarser gravel of the gravel pack, which would severely reduce the gravel permeability. Further, sand will not be produced because it will not have found its way into the liner tubing during the well shut-in.
The presence of the pressure relief valve assembly need not interfere with the introduction of gravel. As shown in FIG. 5, a gravel slurry will typically be introduced through a crossover tool 72 aligned with outlet port 74 in the blank pipe 22. Because the outlet port is located above the valves 36, the valves do not interfere with the application of the gravel pack. After the gravel has been placed, the crossover tool 72 is removed and replaced by the section of the tubing string shown in FIG. 1. The normal operating arrangement is such that the port 74 is overlapped by the end portion of the tubing 18. The port 74 thus has no function after allowing gravel to be delivered through the crossover tool during application of the gravel pack. The valves 36 must, however, be located below the port 74 so as to be exposed to the pressure of the production fluid as it flows up the blank pipe 22. For stimulation work requiring the injection of fluids, the work string packer or tubing packer could be set below or across the crossover ports and the pressure relief valves to isolate them from the system. This would allow fluid injection only over the perforated interval and not through the pressure relief valve or crossover ports.
As indicated above, the force applied by the check valves 36 should be less than the fluid pressure which will cause the gravel pack to become mobile or fluidized. This can be calculated for any particular well by known procedures, including the determination of the minimum pressure drop required for fluidization, as set forth in SPE 14160, a paper of the Society of Petroleum Engineers entitled "Understanding Changing Wellbore Pressures Improves Sand Control Longevity", which was presented at the meeting of the Society of Petroleum Engineers of Sep. 22-25, 1985.
Although the invention has particular utility in the type of well described above, it can also be used in thermal wells in which steam is injected. The valve of the present invention would help eliminate fluidization of the gravel pack when pressures are unbalanced at the time steam flow is first started into the well. During the production cycle of such a well, the valve would close, thus preventing fluidization of the gravel pack again. It will be understood by those skilled in the art that the invention may also have utility in equalizing pressure in horizontal wells.
It can now be appreciated that the present invention provides a simple yet effective way of eliminating the fluidization of gravel packs caused by pressure surges resulting from a well shut-in. It should also be appreciated after reading the foregoing description that the invention is not necessarily limited to all the specific details described in connection with the preferred embodiment, but that changes to certain features which do not alter the overall basic function and concept of the invention may be made without departing from the spirit and scope of the invention, as defined in the appended claims.
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Method and means for preventing fluidization or mobilization of a gravel pack in a fluid producing well as a result of increased fluid pressure caused by a well shut-in or other pressure surge. A pressure relief valve in the form of a check valve is provided in a tubing string below a packer surrounding the string and above the top of the gravel pack. The check valve is held in closed position by a biasing force, such as a spring, which is less than the pressure which will cause mobilization or fluidization of the gravel pack. A pressure surge such as a well shut-in or flow rate decrease increases tubing pressure which causes the check valve to open, thereby relieving the pressure in the gravel pack to a point below the critical level.
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BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic side elevation illustrating the valve lifter mechanism in a high performance push rod engine.
FIG. 2 is a cross-sectional view of an improved valve spring retainer of the type which forms the subject matter of this invention.
FIG. 3 is a cross-sectional view of the improved keeper.
FIG. 4 illustrates the valve spring retainers of the type known to the prior art.
FIG. 5 illustrates an embodiment of the present invention in which steel thrust plates are used to protect the aluminum retainer.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 illustrates the valve lifter mechanism in a typical internal combustion engine. Valve stem 10 is pivotably connected to rocker arm 15 which is pivotably connected to push rod 14 which engages lifter body 16 terminating in roller 18. Roller 18 bears against cam surface 20 on camshaft 22. Valve springs 24 and 26 bear against valve spring retainer 28 and against engine head 30 urging valve stem 10 upward into the closed position. Valve spring retainer 28 is held in position by keeper 32 comprised of retainer locks 34 and 36.
In racing engines, two valve springs 24 and 26 are used so that the valve can be made to open and shut as quickly as possible, of course, more springs can be used. Since valve springs 24 and 26 are normally very stiff, they exert a great deal of force on thrust surfaces 38 and 40 of valve spring retainer 28 often causing it to fracture at its weak point 42 or extrude the locks through the spring retainer.
As shown in FIG. 4, the valve spring retainers known to the prior art have a chambered disc portion 44 which joins a thicker intermediate disc portion 46 which in turn is joined to cylindrical body portion 48. The lower face of chamfered disc portion 44 defines thrust surface 38 while the lower face of intermediate disc portion 46 defines thrust surface 40. Tapered bore 50 passes through the centers of discs 44 and 46 and along the centerline of cylindrical body portion 48. As mentioned previously, weak point 42 occurs where intermediate disc portion 46 joins cylindrical body portion 48. The conventional valve spring retainer has a bore having an inner surface which is conical wherein the angle that the generators of the cone define with the centerline of the bore is approximately 7.5° to 10° . In an effort to strengthen valve spring retainers, many other tapers have been used. However, it has been found that when the taper is decreased to 71/2° , the extreme forces exerted by the springs on the retainer often actually extrude the keeper through the valve spring retainer.
The valve spring retainer of the present invention differs from those known to the prior art, the angle of taper of the bore is not constant. In particular, the taper angle increases in the regions of the valve spring retainer which are furthest from the springs. More particularly, in a preferred embodiment the initial angle of taper of the bore in the portion adjacent to the valve springs is substantially less than the terminal angle of the taper of the bore in the portion away from the valve springs. In a more preferred embodiment, the initial angle of taper of the bore is between 0° and 10° while the terminal angle of taper is between 10° and 40° . It is further preferred that the interior surface of the valve spring retainer be in the form of a smooth surface of revolution. In a still more preferred embodiment, the local radius of curvature of the generator of the interior surface is substantially constant over at least about 75% of the area of the interior surface. It is greatly preferred that the radius of curvature be constant since this enables the valve spring retainers to be easily formed. It is to be emphasized that the valve spring retainers of the present invention are not merely marginally stronger than conventional designs but are so unexpectedly stronger that aluminum can be substituted for titanium.
It is not essential that the interior surface of valve spring retainer 28 be a surface of revolution, substantial benefits can be obtained if the area of the interior surface increases more rapidly in a portion of the retainer away from the valve springs than in a portion closer to the valve springs.
The retainer locks 34 and 36 which hold the novel valve spring retainer of the present invention in place have exterior surfaces which are congruent with the interior surface of the valve spring retainer and therefore mate with the interior surface of valve spring retainer 28 when inserted therein. Protrusions 56 on retainer locks 34 and 36 engage congruent recess formed in valve stem 10.
In some cases, the ends of valve springs 24 and 26 will gouge thrust surfaces 38 and 40 of valve spring retainer 28 and, over time, weaken it. It has been found that this effect may be avoided by interposing thin annular thrust plates 52 and 54 between valve springs 24 and 26 and thrust surfaces 38 and 40 of valve spring retainer 28. Annular thrust plates 52 and 54 engage thrust surfaces 38 and 40 but may be held in place merely by the force of valve springs 24 and 26. Steel or any other suitably hard material may be used for thrust plates 52 and 54 and a substantial savings in weight realized since the flared interior surface construction of valve spring retainer 28 allows it to be comprised of aluminum.
EXAMPLE
Aluminum valve spring retainers were placed in a testing device having a cylindrical rod 11/32 inches in diameter similar to a valve stem and means for pressing against the thrust surfaces of the retainer while maintaining the retainer in place by means of retainer locks as in an engine. The initial angle of taper of the bore was 5° , the terminal angle of taper of the bore was 25° and the radius of curvature of the interior surface formed by the bore was 1.25 inches. The valve spring retainers failed under an average load of 6964 pounds. Conventional titanium valve spring retainers of similar construction but having an angle of taper of 71/2° failed under an average load of 4241 pounds.
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Serious racers strive to squeeze as many revolutions per minute as possible out of their engines. They often use exotic metals like titanium in efforts to minimize the weight of some reciprocating parts. Almost exclusively, serious racers use titanium valve spring retainers to obtain higher speeds. This invention relates to an improved valve spring retainer for use in high performance engines. More particularly, it relates to an aluminum valve spring retainer which is lighter and less costly than titanium retainers of approximately equivalent strength.
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BACKGROUND OF THE INVENTION
The invention relates to a method of and an apparatus (circuit) for protecting the thyristors of a pulse generator of a pulse operated electrostatic precipitator.
In a pulse operated electrostatic precipitator the voltage pulse is provided by triggering a switch element, usually a thyristor or a circuit consisting of series and/or parallel coupled thyristors. When the pulse has reached its peak the current in the thyristors ceases as during the pulse decay, the current flows in return diodes which are coupled in parallel with the thyristors. Once the current in the thyristors has ceased for a certain period of time, the recovering time, they become non-conductive in their forward direction until they are retriggered to provide a new pulse.
If a spark-over occurs in the electrostatic precipitator after the current in the thyristors has ceased, but before the recovery time has elapsed, the thyristors will become forward biased and current will be drawn through the thyristors even though they are only partly conductive. In such a case the current is concentrated in separate, still partly conducting areas of the thyristor semi-conductor chips with the result that these are consequently overloaded and possibly damaged or destroyed.
Nos. EP-A-0066950 and EP-A-014522 describe methods by which retriggering of the thyristors of the pulse generator is established when spark-overs in the electrostatic precipitator are detected. Such a retriggering means that the thyristors can take over the current again without the danger of overload, provided that the retriggering signal has been established by the time the current shifts from the return diodes to the thyristors.
In the narrow interval of time from the moment that the current has shifted from the thyristors to the return diodes and for a few micro-seconds afterwards, due to unavoidable reaction times in the retriggering system, it is difficult to ensure that the retriggering signal can be established by the time that the current shifts back to the thyristors as a consequence of precipitator spark-over.
This is particularly so in extreme operating situations where a low voltage pulse height is used in the electrostatic precipitator simultaneously with use of a high DC voltage. Under these circumstances the time from the occurrence of the spark-over until the current will try to flow in the thyristors will be fractions of a micro-second.
As the time required for detecting the spark-over and generating the retriggering signal typically is one or two micro-seconds, the retriggering signal will consequently be too late.
SUMMARY OF THE INVENTION
The object of the invention is to provide a method and circuit which ensure that the entire critical area is covered by the protective triggering signal.
According to the present invention a protective triggering circuit for a thyristor switch element of a pulse generator is characterized by a high frequency current transformer, the primary winding of which is series-coupled with the pulse circuit of a pulse generator, and across the secondary winding of which is coupled a parallel resistance to provide a current-representing voltage signal thereacross; a peak value measuring unit in which the current-representing voltage peak value is measured a voltage divider for providing a signal proportional to the peak value signal; a voltage comparator in which the current representing voltage is compared with the signal proportional to the peak value, and the output signal of which is an indication that the peak value proportional signal exceeds the current representing voltage and a timer circuit, which is activated to provide a trigger signal by the voltage comparator output signal and an amplifier which transmits a trigger current to a connected cable ignition system.
The invention also includes a method of protecting the thyristor(s) of a pulse generator circuit controlling a pulse operated electrostatic precipitator, characterized in that the thyristors are fed with a trigger signal within the time interval covering the period from immediately before the pulse current shifts from the thyristors into the return diodes to an instant during the conductive interval of the return diodes, so that the trigger signal is fed to the thyristors in case the current suddenly changes direction due to an electrical sparkover in the electrostatic precipitator and tries to flow back into the thyristors, following the sparkover, so fast that a sparkover detecting and retriggering procedure has not yet been completed.
Every spark-over occurring during this interval will consequently result in the thyristors taking over the current without problems, as the protective triggering signal already has been established. If the spark-over occurs at an instant after the protective triggering has ceased, the current in the return diodes has reached such high value that the time from the spark-over until the current tries to shift from the return diodes to the thyristors is sufficiently long to establish the normal retriggering signal.
If no spark-over occurs during the pulse period, the protective triggering signal has no damaging effect, provided that the pulse duration has been chosen so that the time from the ceasing of the protective triggering signal and until the ceasing of the pulse is longer than the recovery time of the thyristors.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in more detail with reference to the accompanying drawings, in which:
FIG. 1, in block diagram form, shows a protective triggering system;
FIG. 2 shows the timing of the signals, in the system during a normal pulse; and,
FIG. 3 shows the timing of the signals in the system during a spark-over.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a pulse circuit comprising a rectifier system R converting an AC main into DC. The DC is led through a series inductance Ls for loading a storage capacitor Cs. The storage capacitor may be discharged to provide a pulse current through a pulse transformer Pt from the secondary winding of which a high tension pulse is led through a coupling condenser Cd to the emission electrode of an electrostatic precipitator Ep.
The discharge of the storage condenser is obtained through triggering the thyristors T in a column of anti-parallelly coupled thyristors T and diodes D. The use of such a column is necessitated by the fact that a single thyristor or diode cannot alone block for the voltage over the column. The column is here only shown schematically as it further comprises capcitors and resistances to distribute the voltage uniformly over the column.
To trigger all the thyristors in the column simultaneously a cable firing system 14 may be used. In such a system the trigger circuits of the thyristors are each coupled to a winding on an individual ring core transformer and a cable is led through all the ring cores. A pulse current through the cable will then induce trigger current in all the individual trigger circuits of the thyristors in the column.
In FIG. 1 is shown only the trigger system for an emergency firing system. A trigger condenser Ct charged from a DC power supply Ps through a series resistance Rs. When a thyristor 12 is triggered the condenser Ct is discharged through a cable passing through ring cores Rc and a trigger current is induced in the trigger circuits of the thyristors T.
FIG. 1 shows the primary winding 1 of a high frequency current transformer 2 coupled into the pulse circuit of a pulse generator (not shown). Consequently both the thyristor current and the return diode current flow therethrough. As a consequence a voltage will be generated across the secondary winding 3 which is loaded by a resistance 4, this voltage being proportional to the current in the pulse circuit. The voltage signal generated, calculated in relation to a fixed reference, is referred to as a. The polarity of the signal a has a positive value when current is passing through the thyristors and a negative value when current is passing through the return diodes.
The voltage signal a is passed to a peak value detector 5, the output signal b of which is set to equal the highest positive value of signal a. Prior to each new pulse it must be ensured that the signal b of the peak value detector has been reset to zero. This is most easily achieved by discharging the memory element of the peak value detector, which element is normally constituted by a capacitor, at a suitable time constant interval.
The signal b is passed to a voltage divider 6, which provides a signal c constituting a suitable fraction of signal b. Signal c is passed to one of the inputs of a voltage comparator, and signal a to the other.
The voltage comparator gives off a signal d when the value of signal c is larger than or equals that of signal a, and the signal d is passed to a timer circuit 8 adapted to give off a signal e for some time after a positive shift in signal d.
The signal e is passed to an amplifier circuit 9, to the output of which there is coupled a cable ignition system 10 which triggers the series and/or parallel coupled thyristors constituting the pulse generator switch element.
As well as being connected to the above described protective triggering system the cable ignition system is connected to the normal triggering system which starts the pulse and to the retriggering system which is actuated by the spark-over detection.
FIG. 2 shows the timing of the signals a to e during a normal pulse. The figure further includes a depiction of the precipitator voltage U, indicating both the DC voltage level and the superimposed pulse voltage, the pulse starting at time t 1 .
The signal a is the voltage signal representing the current in the pulse circuit and is effectively a sine wave signal. The signal b indicates substantially the highest positive peak value obtained by signal a. Once the peak value of a has been attained at t 2 , the value of b gradually descends at a rate high enough to ensure that the value of b is close to zero before the next pulse is given off, but not so high that the value deviates significantly from the ideal peak value within the pulse period (t 1 to t 6 ).
Signal c is proportional to signal b, but with a value corresponding e.g. to one fifth of b. Signal d is a logical signal which is high for so long as signal c is higher than or equals signal a. Immediately following the instant t 1 signal c becomes lower than signal a, so that signal d is subsequently low.
At t 3 the signal a becomes lower than the signal c which at that instant has a size of e.g. one fifth of the peak value of a, which occurred at t 2 .
As signal a substantially follows a sine curve, the occurrence at t 3 will happen at arc sine of one fifth, corresponding to 11.54° before a becomes zero which occurs at t 4 .
When signal a at t 3 becomes lower than signal c, signal d immediately shifts to a high level, which entails also that signal e increases and remains high during the period t 3 to t 5 . As the protective triggering signal is controlled by signal e it is seen that the protective triggering signal is established in the moment the current shifts from the thyristors into the return diodes at t 4 . Thus it is ensured that complete protection exists in the entire critical area.
In the period from t 5 to t 6 the thyristors turn off and recover their hold-off strength, and at t 6 the pulse period ceases.
FIG. 3 shows the signal timing during a pulse during which a spark-over occurs. At t 11 the pulse is started, and signal a attains its peak value at t 12 , which value is maintained in signal b. At t 13 signals a and c cross in value, and signal d is produced, as before, which again entails that signal e, which is a signal of measured duration, is produced. At t 14 the curve a crosses the zero value from positive to negative, reflecting that the current shifts from the thyristors into the return diodes.
A precipitator spark-over occurs at t 15 , reflecting itself in the curve U, which approaches the zero line at a high rate.
At the same time the course of the signal a changes, as the curve starts to reapproach zero, which it reaches at t 16 . At that instant the current shifts from the return diodes back to the thyristors, and it can be seen that signal e, which reflects the protective triggering signal formation, has already been established by the moment of shift so that the thyristors can take over the current without difficulty. At t 17 the value of signal a exceeds the value of signal c, which causes signal d to go low. At t 18 the time measuring signal e stops, and at t 19 signals a exceeds the peak value attained at t 12 , which results in a further increase in signals b and c.
At t 20 signal a has attained its peak value, and at t 21 signals a and c cross each other, thus causing signal d to be produced which again causes the formation of signal e. Signal e is thus present in the interval t 21 to t 22 , so that the protective triggering is again established in this interval.
In this interval the protective triggering is, however, unnecessary as renewed current shift cannot occur, but as it is not damaging either, it is not expedient to enhance the complexity of the electronics with a view to removing the protective triggering.
In the interval t 22 to t 23 the thyristors turn off and recover their hold-off strength, and at t 23 the spark over period ends.
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A protective triggering system protects the thyristor switch element of a pulse generator circuit controlling a pulse operated electrostatic precipitator. The protective triggering is initiated for every pulse in the area around passage of the pulse current from positive to negative, its object being to supplement the spark-over released retriggering system so as to ensure that spark-overs occurring immediately after the current passage across zero do not cause renewed thyristor current in the absence of a triggering signal.
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TECHNICAL FIELD
The present invention relates to a method of calculating the Voltage Standing Wave Ratio (VSWR) of a radio frequency transmission line which is operatively coupled with a first and a second directional coupler, the first directional coupler developing a first voltage indicative of the forward power propagating along the radio frequency transmission in a first direction, and the second directional coupler developing a second voltage indicative of a reflected power propagating along the radio frequency transmission line in a reverse direction. The invention is based on a priority application EP 02 360 381.4 which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
Further, the present invention relates to a base station in a mobile communication system comprising an antenna feeding line and a first and a second directional coupler that are operatively coupled with the antenna feeding line, the first directional coupler developing a first voltage indicative of the forward power propagating along the antenna feeding line in a first direction, the second directional coupler developing a second voltage indicative of a reflected power propagating along the antenna feeding line in a reverse direction.
Such a method and such a base station is per se known, for instance from U.S. Pat. No. 4,110,685.
SUMMARY OF THE INVENTION
In general, an RF-transmission system comprises a transmitter, an antenna and an RF transmission line that couples the transmitter to the antenna. For optimal power transmission, the impedances of these components have to be matched. If the impedance match were perfect, no fraction of the power propagating forward from the transmitter to the antenna would be reflected. In reality, however, a fraction of the power is reflected and propagates as a reflected wave in the reverse direction, thereby, giving rise to a standing wave on the transmission line by superposition of both the wave traveling forward and the reflected wave.
The Voltage Standing Wave Ratio (VSWR) is defined as (1+U_R/U_F)/(1−U_R/U_F) wherein U_R represents a voltage developed by the first directional coupler and indicative of forward power, U_R the voltage developed by the second directional coupler indicative of reflected power.
Hence, the quality of the impedance match affects the VSWR. Accordingly, the VSWR is measured in order to monitor the performance of such a Radio Frequency (RF)-transmission system during operation.
The directional couplers utilized for providing the voltages U_F and U_R comprise conducting structures that are oriented in parallel and antiparallel to the transmission line and that extend along a part of the transmission line. The E- and H-components of the electromagnetic wave traveling along the transmission line couple to these structures and induce the respective voltages U_R, U_F therein.
If the conducting structures had a perfectly straight design and if they were perfectly oriented in parallel and antiparallel, the induced voltages U_F, U_R would depend only on the power of the wave propagating in a single direction, i.e. either forward or backward. The ability of a coupler to distinguish between waves propagating in directions that are reverse to each other is called directivity.
However, due to mechanical deviations from the perfect design and orientation, the wave propagating forward does not only couple to the particular directional coupler provided for developing the respective voltage U_F, but couples also to the other directional coupler. As a consequence, the voltage developed by the other directional coupler that should be indicative of the reflected power only is affected adversely, the other directional coupler, thereby, showing a sub-optimal directivity.
In principle, the same applies to the particular directional coupler provided for developing the voltage U_F indicative of the power propagating forward. This voltage may be adversely affected by the reflected power. Since the reflected power is, in general, small in comparison to the power propagating forward, the impact of the reflected power on the voltage U_F is negligible.
However, the opposite is true for the impact of the power propagating forward on the voltage U_R that is meant to be indicative of the reflected power. Since the reflected power is, in general, small, the voltage U_R might be affected severely by an unwanted impact of the greater power that propagates in the forward direction.
In order to keep this unwanted effect small, it is per se known to manufacture and install the directional couplers with high accuracy in order to achieve a high directivity.
Such a process is time consuming and expensive.
It is, in the light of the prior art outlined above the objective of the invention to provide for a method of measuring the Voltage Standing Wave Ratio (VSWR) of a radio frequency transmission line which reduces the dependency on the mechanical accuracy of the directional couplers involved, thereby reducing manufacturing and installation time and cost.
This objective is achieved by a method as mentioned at the outset, the method comprising the steps of, in a second stage of installation, collecting values of the first and the second voltage, connecting at least one correction value with the second voltage to form a corrected second voltage and forming the Voltage Standing Wave Ratio on the basis of the first voltage and the corrected second voltage.
Further, this objective is achieved by a base station as mentioned at the outset, the base station comprising a control unit receiving the first and the second voltage and having a memory wherein a predetermined correction factor is stored, the control unit forming a corrected second voltage in dependence on the predetermined correction factor, and forming the Voltage Standing Wave Ratio on the basis of the first voltage and the corrected second voltage.
Connecting the second collected voltages with correction values renders is possible to compensate for a lack of accuracy in acquisition of measurement values by utilizing correction values in the subsequent processing of these measurement values. As has already been mentioned, a lack of accuracy in measurement value acquisition may be caused, in the particular technical field of calculating the VSWR of a RF-transmission line from the output values of directional couplers, by a lack of precision in manufacturing and installing the couplers. The opportunity of compensating for a lack of mechanical precision electronically allows to reduce the otherwise required mechanical precision, thereby reducing cost and time in the manufacturing and installment process. In other words: According to the invention, a sub-optimal directivity of directional couplers is electronically compensated. The proposed solution allows for an improvement of a coupler's directivity of approximately 10 dB.
In order to achieve a good compensation, it is preferred to connect the at least one predetermined correction value with the second voltage additively.
Due to the additive nature of mechanically caused measurement value errors, an additive correction value provides for a good compensation.
Since the error induced in the output value of the second directional coupler is dependent on the power propagating forward on the transmission line, it is preferred to form the at least one correction value as being proportional to the first voltage. It should be kept in mind, in this context, that it is the first coupler that is designed to measure the forward power. Hence, the first voltage forms can be expected to reflect the forward power.
It is, further, preferred, to multiply the first voltage with a predetermined correction factor to form the correction value.
Accordingly, the predetermined correction factor may take those influences into account that are not dependent on the forward power, whereas the first voltage takes the dependency on the forward power into account.
In order to obtain a predetermined correction factor that matches the required compensation quality, it is preferred to terminate the radio frequency transmission line with a load resistance of a predetermined quality in a first stage of installation, to collect values of the first and the second voltage, to form a correction factor such, that a predetermined relationship between the first voltage, the second voltage and the correction factor is fulfilled, to store the correction factor, and, to utilize the stored correction factor in a second stage of installation. The first stage of installation is preferably an end of line stage in the manufacturing process of the transmission line and/or base station, whereas the second stage of installation refers to the normal operation of the transmission line and/or base station in the field.
To take the frequency dependency of mechanically induced measurement errors into account, it is preferred to form a plurality of correction factors, each correction factor being allocated to a predetermined frequency of the standing voltage wave.
It is further preferred to consider the predetermined relationship as fulfilled when the sum of the second voltage and the product of the first voltage and the correction factor is equal to zero.
It has turned out that it is this particular relationship that provides for good compensation results.
In order to obtain a good compensation quality, it is further preferred that a first and a second demodulator is interposed between the control unit and the first and second directional coupler, respectively.
The demodulator provides for a splitting up of the in-phase and quadrature-phase components of the coupler's output voltages reflecting both the forward propagating wave and the reflected wave, thereby offering the opportunity to compensate for errors in each individual in-phase and/or quadrature-phase component separately, thereby enhancing the compensation quality.
Further, a base station is preferred that implements at least one of the above outlined methods.
Further advantages can be taken from the description and the enclosed drawings.
It is to be understood that the features mentioned above and those yet to be explained below can be used not only in the respective combinations indicated, but also in other combinations or in isolation, without leaving the scope of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention are shown in the drawings and will be explained in more detail in the description below. In the drawings:
FIG. 1 depicts, schematically, an embodiment of the invention in the form of functional blocks.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 schematically depicts an exemplary embodiment of a base station in a mobile communication system in the form of functional blocks. The base station in its entirety is designated by 10 . Base station 10 comprises a transmitter 12 which is coupled to a first end 14 of a RF-transmission line 16 . The second end 18 of transmission line 16 is coupled to an antenna 20 .
A first directional coupler 22 is operatively coupled to transmission line 16 in order to develop a signal, e.g. a voltage, that is indicative of the power propagating forward from transmitter 12 to antenna 20 on transmission line 16 .
Further, a second directional coupler 24 is operatively coupled to transmission line 16 in order to develop a respective signal indicative of the reflected power, that is the power of the wave that has been reflected at antenna 20 and propagates backwards from antenna 20 to transmitter 12 on transmission line 16 .
In general, the coupling effect is characterized by a quantity K which is defined by the equation K equal to ten times the logarithm (base 10) of the ratio of the power propagating on the transmission line in a certain direction, to the power that is coupled out.
Further, the directivity D of a directional coupler is defined as D plus K equal to ten times the logarithm (base 10) of the ratio of the power that is coupled out.
Arrow 23 represents a coupling interaction of desired direction, that is an transfer of a part of the energy propagating forward on transmission line 16 to first coupler 22 .
Likewise, arrow 25 represents a coupling interaction of desired direction, that is an transfer of a part of the reflected energy propagating backwards on transmission line 16 to second coupler 24 .
For reasons mentioned above, an the second coupler 24 may additionally couple with the power propagating forward on transmission line 16 . Such an undesired coupling interaction that may give rise to an unwanted contribution to the voltage developed by the second directional coupler 24 that is not negligible. Arrow 27 represents such an impact.
Identification reference 26 designates a control unit. Control unit 26 , inter alia, calculates the Voltage Standing Wave Ratio (VSWR) on the basis of output signals, e.g. voltages, of the first directional coupler 22 and the second directional coupler 24 . In FIG. 1 all elements below dashed line 28 are allocated to control unit 26 . Control unit 26 comprises a demodulator 32 , which is enframed by dashed line 30 , analog to digital-converters 34 , 36 , 38 , 40 , a master oscillator 42 , maps or memory cells 44 , 46 , 48 , 50 , multiplicative combinational elements 52 , 54 , 56 , 58 , additive combinational elements 60 , 62 , 64 , 66 and a block 70 that represents the calculation of the Voltage Standing Wave Ratio based on processed output signals of first directional coupler 22 and second directional coupler 24 .
Master oscillator 42 provides a reference frequency f for transmitter 12 and, inter alia, demodulator 32 . Based on this reference frequency f, transmitter 12 generates a signal wave and feeds the signal wave to first end 14 of transmission line 16 . The energy of this signal wave is partly emitted by antenna 20 and partly reflected, thereby giving rise to a standing wave on transmission line 16 . To measure the Voltage Standing Wave Ratio, i.e. the ratio of the maximum and minimum voltage of the standing wave, directional couplers 22 and 24 are provided. Directional coupler 22 is designed and oriented to develop a signal of the power propagating towards the antenna. Likewise, directional coupler 24 is designed and oriented to develop a signal indicative of the reflected power propagating back to transmitter 12 .
The output signal of the first directional coupler 22 is fed to demodulator 32 in order to be decomposited into its in-phase components and quadrature-phase components. To this purpose, generator 72 generates a first demodulation signal, e.g. a cosine of frequency f. Frequency f is provided by master oscillator 42 . The cosine outputted by generator 72 is multiplied, in combinational element 76 with the output voltage U_F (U_forward) of first directional coupler 22 . Accordingly, the resulting product represents the in-phase component of U_F.
Generator 74 generates a sine with frequency f. Accordingly, the product of the sine generated by generator 74 and the output voltage U_F of the first directional coupler 22 , which is formed in combinational element 78 , represents the quadrature-phase component of U_F.
The output of generator 72 is, further, multiplicatively combined with the output voltage U_R of the second directional coupler 24 in combinational element 80 . Likewise, the output of generator 74 is combined multiplicatively in combinational element 82 with the output O_R of the second directional coupler 24 . Hence, combinational element 80 provides for the in-phase component of U_R and combinational element 82 provides for the quadrature-phase component of U_F.
The in-phase components and quadrature-phase components of signals U_F, U_R are converted to digital signals in analog to digital converters 34 , 36 , 38 and 40 . The digitized signals based on U_F are fed, without further processing, into block 70 , in which the Voltage Standing Wave Ratio VSWR is calculated. Accordingly, the digitized signals based on U_F are processed without being corrected for a potential impact of the reflected power. This is acceptable, since, for reasons outlined above, the output voltage U_F of the first directional coupler 22 is not affected severely by the reflected energy propagating transmitter 12 on transmission line 16 .
However, converse considerations apply to the output voltage U_R of the second directional coupler 24 . In fact, this output voltage U_R may be affected severely by the power propagated forward to the antenna 20 . The purpose of second directional coupler 24 is to develop a voltage indicative of the reflected power only. However, the reflected power is, in general, small in comparison to the power propagating in forward direction. Accordingly, a small fraction of power propagating forward on transmission line 16 may induce a severe disturbance to the small signal indicative of the reflected power and outputted by directional coupler 22 . Hence, if such a disturbance occurs, the output signal O_R has to be corrected in order to calculate the Voltage Standing Wave Ratio correctly.
To accomplish such a correction, correction factors K 1 , K 2 , K 3 and K 4 are stored in memory cells 44 , 46 , 48 and 50 , respectively.
Correction factor K 1 is multiplied with the quadrature-phase component of U_F in combinational element 52 . The resulting product is added to the in-phase component of U_R in combinational element 60 . Similarly, the quadrature-phase component of U_F is multiplied with a correction factor K 2 outputted by memory cell 46 in combinational element 54 and added to the quadrature-phase component of U_R in combinational element 62 .
Further, the in-phase component of U_F is multiplied in combinational element 56 with a correction factor K 3 read out from memory cell 48 and the resulting product is added to the in-phase component U_R in combinational element 64 . Similarly, the in-phase component of U_R is multiplied in combinational element 58 with correction factor K 4 read out from memory cell 50 and the resulting product is added to the quadrature-phase component of U_R in combinational element 66 .
Memory cells 44 , 46 , 48 and 50 may be comprised in respective maps that may be addressed by the reference frequency f provided by master oscillator 42 . Such a design takes the frequency-dependence of the correction factors K 1 , . . . K 4 into account.
As a consequence, the in-phase and quadrature-phase components of U_R may be compensated for a disturbance caused by a lack of mechanical precision in manufacturing and installing the second directional coupler 24 electronically.
FIG. 1 shows the base station 10 in a second stage of installation, i.e. during normal operation in the field with an antenna 20 attached.
To establish correct values for the correction factors K 1 , . . . K 4 , base station 10 is, in a first stage of installation, calibrated. For calibration, antenna 20 is substituted by a defined impedance that generates a defined reflection at the second end 18 of transmission line 16 . Accordingly, a defined Voltage Standing Wave Ratio on transmission line 16 is generated.
For instance, the calibration impedance terminating transmission line 16 may be designed to generate zero reflection. Accordingly, the voltage U_R developed by the second directional coupler 24 should be zero. Any voltage developed by the second directional coupler 24 under these circumstances is induced by the power propagating forward on transmission line 16 due to a lack of mechanical accuracy in the design and/or installation/orientation of second directional coupler 24 .
To obtain appropriate correction values, the requirement U_R+K*. U_F=0 is established. In complex notation, U_R can be written as the sum of the in-phase component and the quadrature-phase component times the complex number j. In complex notation, U_F can be written as AI+j*AQ wherein AI represents the in-phase component of U_F and AQ represents the quadrature_phase component.
Similarly, U_R can be written as BI+j*BQ and K can be written as K=KI+j*KQ.
Substituting the respective variables in the equation mentioned above leads to:
− BI=KI*AI−KQ*AQ and
− BQ=KI*AQ+KQ*AI.
Accordingly, the unknown coefficients KI, KQ can be calculated from the values of BI, BQ, AI, and AQ that are measured in the first stage of installation in a calibration procedure.
A comparison with the relationships established by the structure of FIG. 1 shows that
K 1 equals KQ, K 2 equals −KI, K 3 equals −KI, and K 4 equals −KQ.
Accordingly, the correction factors K 1 , . . . , K 4 may be pre-determined in a calibration process in the manner outlined above. Preferably, the calibration process is integrated in an end of line test procedure after in the manufacturing process.
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A method and base station apparatus are presented for calculating the Voltage Standing Wave Ratio of a radio frequency transmission line which is coupled with a first and a second directional coupler, the first directional coupler developing a first voltage indicative of the forward power propagating along the radio frequency transmission line in a first direction, the second directional coupler developing a second voltage indicative of a reflected power propagating along the radio frequency transmission line in a reverse direction. The method includes, in a second stage of installation, collecting values of the first and the second voltage, connecting at least one correction value with the second voltage to form a corrected second voltage, and forming the Voltage Standing Wave Ratio on the basis of the first voltage and the corrected second voltage. The correction value is obtained in a calibration process in a first stage of installation.
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PRIOR APPLICATIONS
[0001] This application is a U.S. national phase application based upon International Application No. PCT/SE00/01435, filed 5 Jul. 2000; which claims priority from Swedish Application No. 9902586-8, filed 6 Jul. 1999.
TECHNICAL FIELD
[0002] The present invention relates to a system and a process for oxygen delignification.
BACKGROUND AND SUMMARY OF THE INVENTION
[0003] A number of different processes for oxygen delignification are known. For example, U.S. Pat. No. 4,259,150 presents a system with multistage oxygen bleaching in which, in each stage, the pulp is first mixed to a lower consistency with O 2 , water and NaOH, followed by a thickening back to the consistency level which the pulp had prior to the stage in question. The aim is to obtain an economic, chlorine-free bleaching with high yield. At the same time, the kappa number can be lowered, by means of repeated stages, from 70 down to 15 or even less than 15.
[0004] Swedish Patent C,467.582 presents an improved system for the oxygen bleaching of pulp of medium consistency. By means of controlling the temperature in an optimized manner, an oxygen bleaching takes place in a first delignification zone at a low temperature, with this being followed by a second delignification zone at a temperature which is 20-40 degrees higher. The aim is to obtain an improved yield and an improved viscosity, while retaining the dwell time, in association with industrial use.
[0005] Other variants of oxygen delignification in two stages have also been patented in addition to Swedish Patent No. C,467.582. Swedish Patent No. C,505.147 presents a process in which the pulp should have a high pulp concentration in the range of 25-40% in the first stage and a concentration of 8-16% in the second stage, at the same time as the temperature in the second stage should be higher than, or equal to, the temperature in the first stage, in line with the temperature difference which is recommended in Swedish Patent No. C,467.582. The advantages of the solution in accordance with Swedish Patent No. C,505.147 are stated to be the possibilities of admixing more oxygen in the first high-consistency stage without there being any risk of channel formation but where, at the same time, unused quantities of oxygen can be bled off after the first stage in order subsequently to be admixed in a second mixer prior to the second stage.
[0006] Swedish Patent No. C,505.141 presents a further process which is an attempt to circumvent Swedish Patent No. C,467.582, since that which it is sought to patent is stated to be that a temperature difference between the stages does not exceed 20 degrees, i.e., the lower suitable temperature difference patented in SE,C,467.582, but that a temperature difference should nevertheless be present. In addition to that, it is stated that a) the pressure should be higher in the first stage and b) that the dwell time is short in the first stage, i.e., in the order of magnitude of 10-30 minutes, and also c) the dwell time in the second stage is longer, i.e., in the order of magnitude of 45-180 minutes.
[0007] A lecture entitled “Two stage MC-oxygen delignification process and operating experience” which was given by Shinichiro Kondo from the Technical Div. Technical Dept. OJI PAPER CO. Ltd. At the 1992 Pan-Pacific Pulp & Paper Technology Conference, 99 PAN-PAC PPTC, Sep. 8-10, Sheraton Grande Tokyo Bay Hotel & Towers, presents a successful installation which was constructed with two-stage oxygen delignification in 1986 in a plant in Tomakomai.
[0008] In this OJI PAPER plant in Tomakomai, the pulp was fed, with a pressure of 10 bar, to a first oxygen mixer (+team) followed by an after-treatment in a pre-retention tube (pre-reactor), with a 10 minute dwell time in which the pulp pressure is reduced to a level of about 8-6 bar due to pipe losses, etc. After that, the pulp was fed to a second oxygen mixture followed by an after-treatment in a reactor at a pressure of 5-2 bar and with a dwell time of 60 minutes. It was stated at this point that preference would have been given to having a pre-retention tube which would have given a dwell time of 20 minutes but that it was not possible to construct this due to lack of space. The OJI PAPER stated that, by using this installation, they had succeeded in obtaining an increase in kappa reduction at a lower cost in chemicals and with the pulp viscosity being improved.
[0009] Most of the prior art has consequently been directed towards a higher pressure in the first reactor at a level of about 6(8)-10 bar. A pressure in the first reactor of up to 20 bar has even been discussed in certain extreme applications. This results in it being necessary to manufacture the reactor spaces which are required for the first delignification zone such that they can cope with these high pressure levels, with a consequent requirement for substantial material thickness and/or good material qualities, which in turn result in an expensive installation.
[0010] In pulp suspensions in industrial production processes, there are large quantities of readily oxidizable constituents/structures which already react under modest process conditions. It is therefore advantageous, in a first stage, to add oxygen in quantities which are such that this part of the pulp which is relatively easily oxidized is allowed to oxidize/react first of all. Severe problems arise if an attempt is made to compensate for this by over-adding oxygen since there is the immediate danger of canalization problems, as mentioned in Swedish Patent No. C,505.147.
[0011] One object of the present invention is to avoid the disadvantages of the prior art and to obtain an oxygen delignification which gives increased selectivity. The present invention permits an optical practical application of the theories regarding a first rapid phase and a second slower phase during the oxygen delignification process, with the optimal reaction conditions being different between the phases.
[0012] At the high hydroxide ion concentrations and high oxygen partial pressures which are conventionally employed in the first stage, the carbohydrates are attacked more than is necessary, thereby impairing the quality of the pulp. A lower oxygen partial pressure, and preferably a lower temperature as well, in the first stage as compared with the second stage decreases the rate of reaction for the breakdown of carbohydrates more than it decreases the rate of reaction for the delignification, leading in turn to an increase in the total selectivity on the pulp after the two stages.
[0013] Another object of the present invention is to allow a simpler and cheaper process installation in which at least one pressure vessel, in a first delignification zone, can be manufactured using thinner material and/or using a lower material quality which is suitable for a lower pressure class.
[0014] Yet another object is also to make it possible to use steam at moderate pressure especially when there is a need to increase the temperature substantially between the first and second stage and when the pressure in the second stage is considerably higher than that in the first stage. In most cases, the supply of medium-pressure steam and low-pressure steam is very good in a pulp mill whereas high-pressure steam is in short supply due to the large number of processes which require high-pressure steam. This also makes it possible to convert existing single-vessel delignification systems where, with the previously the prior art for converting to a two-stage design, a restriction has been imposed by the fact that the prevailing pressure in the plant's steam grid has not enabled a sufficiently large quantity of steam to be admixed with the pulp in order to achieve the desired temperature in the second delignification stage.
[0015] Yet another object is to optimize the mixing process in each position such that only that quantity of chemicals/oxygen is added which is consumed in the subsequent delignification zone and where the admixture of chemicals/oxygen does not need to compete with the simultaneous admixture of steam for the purpose of increasing the temperature to the desired level. In this way, it is possible to dispense with bleeding systems for overshooting quantities of oxygen at the same time as it is possible to reduce the total consumption of oxygen, which in turn reduces the operating costs for the operator of the fibre line and thus shortens the pay-off time. At the same time, it is possible to select a smaller size of dynamic mixer for admixing chemicals, which mixer is dimensioned solely for the volumes of chemicals which are actually being admixed.
[0016] Yet another object is to increase, in an oxygen delignification system having a certain total volume of the first and second stages, a so-called H factor by operating the first stage for a short time at low temperature and operating the second stage for a longer time at a higher temperature. Thus, in connection, for example, with conversions of existing single-vessel oxygen delignification stages, a simple conversion, including a small pre-reactor and a modest increase in the reaction temperature in the existing reactor, can increase the H factor and at the same time improve the selectivity over the oxygen stages.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 shows a system for oxygen delignification in two stages in accordance with the invention; and
[0018] FIG. 2 diagrammatically shows the kinetics of the oxygen delignification and the advantages which are gained relative to the prior art with regard to reduction in kappa number and an increased H factor.
DETAILED DESCRIPTION
[0019] FIG. 1 shows an installation, according to the present invention, of a system in an existing plant in which the oxygen delignification process needed upgrading.
[0020] An existing first MC pump 1 (MC=medium consistency, typically a pulp consistency of 8-18%) is connected to a tipping chute 2 for forwarding to an existing first MC mixer 3 . The first mixer 3 is a so-called dynamic mixer, in which a motor-driven rotor agitates the pulp in at least one narrow fluidization gap. The dynamic mixer is preferably a mixer type which corresponds to that which is shown in U.S. Pat. No. 433,920, in which a first cylindrical fluidization zone is formed between the rotor and the housing and a second fluidization zone is formed between a radially directed rotor part and housing, which mixer is hereby introduced as a reference. A mechanical agitation is required in order to obtain a uniform admixture of the chemical charge in question in the whole of the pulp suspension, with the aim of the pulp being bleached/treated uniformly throughout the whole of the volume of the pulp.
[0021] An admixture of chemicals, chiefly oxygen, takes place in the first MC mixer 3 , after which the pulp was, in the existing system, fed to an oxygen reactor 6 . The combination of a first MC pump 1 followed closely by an MC mixer 3 can be termed a perfect pair. This is the case since the pump primarily pressurizes the pulp flow to a given degree, thereby facilitating a finely divided supply of the oxygen to the MC mixer which follows directly thereafter.
[0022] In accordance with the invention, an upgrading of the oxygen delignification process is achieved by introducing a static mixer 8 , i.e., a non-rotating or mechanically agitating mixer 8 for increasing the temperature by means of adding steam. The static mixer 8 is preferably of a construction which has been shown in SE,C,512.192 (=PCT/SE00/00137), where steam is conducted in as thin jets through a number of holes which are uniformly distributed over the periphery of a pulp-conveying pipe, which mixer is hereby introduced as a reference.
[0023] The static mixer 8 is arranged directly after the oxygen reactor 6 and followed by a second MC pump 4 and a second agitating MC mixer 5 , of the same type as the mixer 3 , which acts directly after the MC pump 4 . The system is assembled such that the coupling pipe 6 forms a first delignification zone between the outlet of the first MC mixer 3 and the inlet of the non-rotating mixer 8 , which zone gives rise to a dwell time R T of 2-20 minutes, preferably 2-10 minutes and even more advantageously 3-6 minutes.
[0024] The second MC pump 4 is controlled such that the resulting pressure in the dwell line 6 is preferably in the interval 0-6 bar, preferably 0-4 bar. Preferably, the second pump 4 is controlled by means of its rotational speed being controlled by a control system PC depending on the pressure which prevails, and is detected, in the first delignification zone 6 .
[0025] The temperature in the whole of the first delignification zone 6 can be kept low, preferably at the level which the system allows without adding steam, but preferably with the pulp entering the first delignification zone being at a temperature of about 85° C., ±10° C.
[0026] The non-rotating mixer 8 is connected in after the first delignification zone, as are then the second MC pump 4 followed by the second MC mixer 5 . This second perfect pair combination is controlled such that the resulting pressure in the oxygen reactor 10 , which forms a second delignification zone, reaches a level of at least 3 bars over-pressure at the top of the reactor. In conventional applications, the pressure in the second MC mixer should be at least 4 bar higher than the pressure in the first MC mixer; alternatively, the increase in pressure in the second pump should reach 4 bar. In connection with practical implementation in conventional oxygen stages, an initial pressure is obtained within the interval 8-10 bar, corresponding to the pressure at the inlet to the reactor.
[0027] In accordance with the present invention, the temperature of the pulp in the second delignification zone is increased by supplying steam to the non-rotating mixer directly after the first delignification zone and before the pressure-raising pump 4 comes into play. The steam supply is expediently controlled using a control system TC, which comprises a control valve V on the line 7 for the steam supply and a feeding-back measurement of the temperature of the pulp which is leaving the mixer. The temperature is expediently raised to a level of 100° C.±10° C., but preferably at least 5° C. higher than the temperature in the first delignification zone. As a result of the steam being added before the pulp is given the higher pressure which is required for the final phase of the delignification:
a higher temperature can be obtained; the pressure of the available steam does not need to be so high; and the mixers for adding chemicals/admixing oxygen do not need to be burdened with a supply of steam as well, which will otherwise reduce their efficiency.
[0031] The volume of the second delignification zone, i.e., the second reactor, is expediently designed such that it is at least 10 times greater than the volume of the first delignification zone, i.e., a retention time of at least 20-200 minutes, preferably 20-100 minutes and even more advantageously within the range 50-90 minutes.
[0032] FIG. 2 diagrammatically shows the kinetics of the oxygen delignification and the advantages with regard to the principles of kappa number reduction which are obtained relative to the prior art. Curve P 1 shows the principle of a reaction course during the initial phase of the delignification. This part of the delignification proceeds relatively rapidly and is typically essentially complete after a good 20 minutes.
[0033] However, after a relatively short time, typically only 5-10 minutes, the final phase P 2 of the delignification takes over and begins to dominate as far as the resulting delignification of the pulp is concerned. A typical subdivision of the delignification into two stages in accordance with the prior art is shown at line A, with stage 1 being to the left of the line A and stage 2 being to the right of the line A. It follows from this that two different dominating processes, i.e., the initial phase of the delignification on the one hand, but also its final phase, actually take place in stage 1 . It can be concluded from this that it becomes impossible to optimize the process conditions in stage 1 for both these delignification phases.
[0034] Instead, a subdivision of the delignification into two stages in accordance with the invention is shown as a line B, a stage 1 is to the left of the line B and stage 2 is to the right of the line B. This makes it possible to optimize each stage for the process which dominates in the stage. The curve H A shows the temperature integral plotted against time (the H factor) which is typically obtained when implementing a delignification process in two stages in accordance with the prior art, corresponding to the line A.
[0035] As can be seen from the figure, it is possible to use the stage subdivision in accordance with the invention to obtain an H factor which is higher than that which is typically obtained in current installations. This can be done without foregoing demands for high selectivity over the oxygen delignification system. The invention also opens up ways of upgrading, with a small investment, an existing 1-stage process of comparatively low selectivity to a 2-stage system of better selectivity without having to build a new large reactor or even two such reactors. According to the present invention, the initial phase of the oxygen delignification is dealt with in the pre-reactor, after which the temperature in the existing reactor can even be increased, if so required, in association with the conversion, and an increased H factor can in this way be combined with increased selectivity.
[0036] The invention can be modified in a number of ways within the context of the inventive concept. For example, the first delignification zone can consist of a pre-retention tube which is vertical but in which the pressure in some part of this pre-retention tube, including its bottom, is at least 4 bar lower than the pressure in the initial part of the second delignification zone.
[0037] Further delignification zones, or intermediate washing/bleaching or extraction of the pulp, can be introduced between the first and second delignification zones according to the invention. For example, a third perfect pair combination, i.e., a pump with a mixer following it, can be arranged between the zones. What is essential is that the first delignification zone is characterized by a lower pressure, a short dwell time and a moderate temperature, and that the concluding, final delignification zone is characterized by a higher pressure (a pressure which is at least 4 bar higher than that of the first zone), a longer dwell time (a dwell time which is at least 10 times longer than that in the first zone) and an increased temperature (a temperature which is preferably at least 5 degrees higher than that in the first zone).
[0038] Where appropriate, it should be possible to charge a first mixer, or an intermediate mixer in a third perfect pair combination, with oxygen, at least some part of which is blown off from the reactor 10 . The economic basis for such a recovery of oxygen is poor since the cost of oxygen is relatively low.
[0039] In order to ensure optimal process conditions, one or other, preferably the second, or both of the MC pumps can be rotation speed-controlled in dependence on the pressure in the first delignification zone.
[0040] The present invention can also be modified by a number of varying additions of other chemicals either together with the oxygen or separately from the addition of oxygen, in a separate adding position, which chemicals are selected and suitable for the specific fibre line and the pulp quality in question, such as
alkali/NaOH for adjusting the pH level to that which is suitable for the pulp quality in question, agents for protecting cellulose, for example MgSO 4 or other alkaline earth metal ions or compounds thereof; additions of complex agents which are performed prior to adding oxygen, with subsequent removal of precipitated metals, where appropriate, chlorine dioxide; hydrogen peroxide or organic or inorganic peracids or salts thereof; free-radical capturing agents, such as alcohols, ketones, aldehydes or organic acids; and carbon dioxide or other additives.
[0048] Where appropriate, it should also be possible to degas exhaust gases, such as residual gases, in immediate conjunction with the second pump, preferably by means of the pump being provided with internal degassing, preferably a pump termed a degassing pump.
[0049] While the present invention has been described in accordance with preferred compositions and embodiments, it is to be understood that certain substitutions and alterations may be made thereto without departing from the spirit and scope of the following claims.
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The system is for the oxygen delignification, in at least two reaction stages, of pulp that consists of lignocellulose-containing material having a mean concentration of 8-18% pulp consistency. The system has a first pump followed by a first oxygen mixer that is followed by a first delignification zone. The first delignification zone is followed by a second steam mixer that is followed by a second pump that is followed by a third oxygen mixer and a second delignification zone.
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This is a continuation of Application No. 10/044,456, filed Jan. 10, 2002, now U.S. Pat. No. 6,595,334.
FIELD OF THE INVENTION
The present invention relates to luggage, and more particularly to small luggage cases, such as business cases, computer cases, backpacks and the like which may be provided with shoulder straps or hand grips for carrying, or with wheels for rolling on a surface and an extendable handle for pulling by a user.
BACKGROUND OF THE INVENTION
In the past, most items of luggage, such as those used for overnight travel, were formed of stiff or rigid material as rigid enclosures. Similarly, items of luggage used to carry papers, personal items and other materials to be kept close at hand, particularly when using public transportation, such as airplane or trains, typically referred to as briefcases, where also either made of stiff or rigid material as rigid enclosures, or of rather stiff material such as leather with some flexible portions to permit expansion and contraction. More recently, both types of luggage mentioned above have been formed as relatively unstructured enclosures made of non-rigid natural or man-made materials such as leather, canvas or nylon. The non-rigid material forming the enclosure is assembled to provide luggage of a particular shape. In some cases, a rigid framework is provided to maintain the desired shape of the luggage.
A further development in luggage industry has been the use of wheeled luggage for checked baggage, carry-on baggage and some business cases. For the purposes of this discussion, the term “business case” may include cases designed to hold and transport portable computers. Luggage of this type typically includes wheels and an extendable handle, so that the user can pull the case along on its wheels, without having to bear its full weight. Additional items may be supported by the handle assembly or attached to the case itself, to ease the burden of the user when moving through airport concourses or along city sidewalks. Examples of such additional items are garment bags and other business cases.
The most commonly available luggage of this type has wheels and extendable handle permanently attached to the luggage. When luggage of this type is not being transported on its wheels, the extendable is retracted. When this arrangement is included as part of the design of a business case, the bulk and weight of the case, with its integrated wheel and handle assembly, is are often cumbersome and uncomfortable to carry.
For instance, the same case may be used during business trips and while commuting between home and office. On a business trip the integrated handle and wheel assembly is a blessing; on a commuter train, the bulk and weight of the assembly may be a curse. When such a business case or backpack is carried by shoulder straps or handles, the typically unpadded structure of the retracted handle and wheel assembly can irritate the user's rib cage.
Accordingly, it would be advantageous to provide a luggage system consisting of a case and a wheel and handle assembly which may be readily secured to the case when needed and removed when not needed. Further, it would be desirable to provide the readily removable wheel and handle assembly and the case with complementary devices for securing them to each other. It would be further desirable that the removable wheel and handle assembly and the case be of complementary design, so as to be of pleasing appearance when secured to each other. Finally, it would be desirable that the wheel and handle assembly provide extra strength to the case, particularly when it is fully packed and heavy.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a luggage system which includes a case provided with straps or handles for carrying the case and a wheel and extendable handle assembly for dragging the case. It is a further object of this invention to provide a wheel and extendable handle assembly which may be removably attached to the case.
It is another object of this invention to provide a case with a removable wheel and extendable handle assembly which are attached to each other by complementary fasteners provided on the case and the removable wheel and extendable handle assembly.
It is a still further object of this invention to provide a removable wheel and extendable handle assembly which provides additional protection and rigidity to the case when attached to the case for dragging of the case.
A case with removable wheel and extendable handle assembly in accordance with this invention includes a soft sided case having one or more main storage volumes made accessible by openings which may be held closed by fastening devices. The case may also have additional storage areas for as pockets on the sides of the walls of the main storage areas. Handles are secured to the walls of the main storage area for a person to grasp while carrying the case. In of the preferred embodiments of this invention, straps are secured to the walls of the main storage area which may be used to carry to case as a back pack. A removable wheel and extendable handle assembly in accordance with this invention includes a partial housing having a base, sides and a back. A pair of wheels are mounted on the partial housing adjacent the corners formed by the base, sides and back. The back is provided with an arrangement for telescopically receiving an extendable handle assembly. In a preferred embodiment of this invention, the back of the partial housing is of essentially the same height as the case, the base is of essentially the same width and depth as the case, and the sides are of reduced height as compared to the back. Complimentary fastening devices are provided on the removable wheel and extendable handle assembly and on the case, the removable secure the assembly to the case. In a preferred embodiment of this invention, the complimentary fastening devices are in the form of zippers, similar to those used to provide access to the main storage volume and the auxiliary storage volumes. More particularly, one portion of a zipper is secured around the edge of the back of the partial housing, while the other portion of the zipper is provided on the case, such that when the case is place in the partial housing, the zipper portions may be secured to each other in the usual manner. Similarly, one portion of a zipper may be provided on the edge of the bottom opposite the back, and the other portion on the case, such that when the case is placed in the partial housing, the zipper portions may be secured to each other in the usual manner.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a general perspective view of a business case in accordance with the preferred embodiment of this invention transported as a brief case;
FIG. 2 is a perspective view of a removable wheel and extendable handle assembly in accordance with this invention for use with the case shown in FIG. 1 ;
FIG. 3 is a perspective view showing the manner of placement of the case of FIG. 1 in the removable wheel and extendable handle assembly of FIG. 2 ;
FIG. 4 is a perspective view showing the case of FIG. 1 placed in the removable wheel and extendable handle assembly of FIG. 2 ;
FIG. 5 is a front perspective view showing the case of FIG. 1 placed in the removable wheel and extendable handle assembly of FIG. 2 , and a series of detail figures illustrating the attachment process at the bottom of the combined assembly;
FIG. 6 is a rear perspective view showing the case of FIG. 1 placed in the removable wheel and extendable handle assembly of FIG. 2 , and a series of detail figures illustrating the attachment process at the top and sides of the combined assembly;
FIG. 7 is a perspective view showing the case of FIG. 1 being finally secured in the removable wheel and extendable handle assembly of FIG. 2 , with the extendable handle partially extended;
FIG. 8 is a perspective view showing the case of FIG. 1 secured in the removable wheel and extendable handle assembly of FIG. 2 , with the extendable handle extended and being used to pull the case.
FIG. 9 ; is a general perspective view of a back pack in accordance with an alternative embodiment this invention;
FIG. 10 is a perspective view of a removable wheel and extendable handle assembly in accordance with this invention for use with the case shown in FIG. 9 ;
FIG. 11 is a perspective view showing the manner of placement of the case of FIG. 9 in the removable wheel and extendable handle assembly of FIG. 10 ;
FIG. 12 is a perspective view showing the case of FIG. 9 placed in the removable wheel and extendable handle assembly of FIG. 10 ;
FIG. 13 is a perspective view showing the case of FIG. 9 placed in the removable wheel and extendable handle assembly of FIG. 10 , and a series of detail figures illustrating the attachment process at the bottom of the combined assembly;
FIG. 14 is a perspective view showing the case of FIG. 9 placed in the removable wheel and extendable handle assembly of FIG. 10 , and a series of detail figures illustrating the attachment process at the top and sides of the combined assembly;
FIG. 15 is a perspective view showing the case of FIG. 9 being finally secured in the removable wheel and extendable handle assembly of FIG. 10 , with the extendable handle partially extended;
FIG. 16 is a perspective view showing the case of FIG. 9 secured in the removable wheel and extendable handle assembly of FIG. 10 , with the extendable handle extended and being used to pull the case.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1 , a case 10 in one example comprises a business case 10 and/or a luggage case 10 . The business case 10 in accordance with a preferred embodiment of this invention is provided with a shoulder strap 12 so as to be carried by the user. Business case 10 is generally of a rectangular shape, with access being provided to three main storage compartments by zippers 14 and 16 . Auxiliary storage compartments 18 and 20 are provided on one side of the case 10 .
The luggage case 10 in one example comprises a small luggage case 10 . The small luggage case 10 in one example comprises top 102 , bottom 104 , face 106 , face 108 , side 110 , and side 112 . From one user perspective the face 106 comprises a front of the small luggage case 10 and from another user perspective the face 108 comprises the front of the small luggage case 10 .
The small luggage case 10 comprises a first dimension, for example, a height, between the top 102 and the bottom 104 . The small luggage case 10 comprises a second dimension, for example, a width, between the side 110 and the side 112 .
Referring to FIG. 2 , wheel and handle assembly 22 in accordance with this invention is shown to include a partial housing shell 24 . Shell 24 includes back 26 , base 28 and side members 30 and 32 . Wheel housings 34 are formed in the rear base of shell 24 . Wheels 51 are rotatably mounted within wheel housings 34 as shown in FIG. 8 . Telescoping extendable handle 36 is slidably mounted to the interior of shell back 26 by upper bracket 38 and lower bracket 40 . Shell back 26 includes surround gusset 42 which extends around the upper perimeter of shell back 26 to form a flexible top and upper sides of shell 24 . Access zipper 44 is provided in surround gusset 42 to provide access, when open, for handle 36 , and through which handle 36 is extended.
Upper zipper half 46 is stitched to the leading edge of surround gusset 42 . Lower zipper half 48 is stitched to the leading edge of shell base 28 . Support feet 50 are provided on the bottom of base 28 .
Referring to FIGS. 2 and 6 , the wheel and handle assembly 22 in one example comprises the shell 24 , the wheel housings 34 , top 202 , bottom 204 , face 206 , face 208 , side 210 , side 212 , and skid plates 610 . From one user perspective the face 206 comprises a front of the wheel and handle assembly 22 and from another user perspective the face 208 comprises the front of the wheel and handle assembly 22 .
The wheel and handle assembly 22 comprises a first dimension, for example, a height, between the top 202 and the bottom 204 . The wheel and handle assembly 22 comprises a second dimension, for example, a width, between the side 210 and the side 212 .
Referring to FIGS. 5 , 6 , and 8 , the wheel housings 34 in one example cover various portions of the wheels 51 . Referring to FIG. 5 , the wheel housings 34 cover potion 502 of the wheels 51 at position 504 of the wheel and handle assembly 22 . Referring to FIG. 6 , the wheel housings 34 cover portion 606 of the wheels 51 at position 608 of the wheel and handle assembly 22 . Reneging to FIG. 6 , the wheel housings 34 cover portion 802 of the wheels 51 at position 804 of the wheel and handle assembly 22 .
Referring to FIGS. 3 and 4 , business case 10 is shown being lowered and inserted in housing shell 24 of wheel and handle assembly 22 . Shell 24 is sized to provide a snug fit around case 10 .
The small luggage case 10 is readily releasably securable to the wheel and handle assembly 22 . Upon readily releasable securement in one example, the face 106 of the small luggage case 10 abuts the face 206 of the wheel and handle assembly 22 . The top 102 of the small luggage case 10 is adjacent to the top 202 of the wheel and handle assembly 22 . The bottom 104 of the small luggage case 10 is adjacent to the bottom 204 of the wheel and handle assembly 22 . The side 110 of the small luggage case 10 is adjacent to the side 210 of the wheel and handle assembly 22 . The side 112 of the small luggage case 10 is adjacent to the side 212 of the wheel and handle assembly 22 . Referring to FIG. 5 , business case 10 is attached to the leading edge of shell base 28 . The means of attachment in the illustrated embodiment zippers at the front bottom edge of the assembly and at the back top and sides of the assembly. It is anticipated, however, that other suitable attaching means could be used, including snaps and hook and loop fastening means. In addition, it is anticipated that the fastening means used in the various embodiments of the present invention could be lockable to secure business case 10 to shell base 28 . In this embodiment, the lower frontal attachment is made by mating zipper half 52 , stitched to the front bottom edge of case 10 , and lower zipper half 48 , stitched to the leading edge of shell base 28 .
Similarly, as shown in FIG. 6 , zipper half 54 , stitched adjacent to and around the upper rear sides and the top rear edge of case 10 , and upper zipper half 46 on shell 24 are sized and located to mate, forming a complete zipper around the rear top edge and upper rear sides of the assembly.
The small luggage case 10 comprises perimeter 602 about the face 106 . The zipper half 54 in one example is stitched along a number of portions of the perimeter 602 . For example, the zipper half 54 is stitched along the side 110 , the top 102 , and the side 112 .
The wheel and handle assembly 22 comprises perimeter 604 about the face 206 . The upper zipper half 46 in one example is stitched along a number of portions of the perimeter 604 . For example, the upper zipper half 46 is stitched along the side 210 , the top 202 , and the side 212 .
FIGS. 7 and 8 illustrate the completely assembled unit. In FIG. 7 , telescoping extendable handle 36 is extracted from access zipper 44 so that the case may be pulled behind the user.
An alternative embodiment of the present invention is shown in FIGS. 9–16 . Referring to FIG. 9 , back pack 56 is provided with a pair of shoulder straps 58 , one of which is shown, so as to be carried by the user. The back pack 56 is generally of a rectangular shape, with access being provided to three main storage compartments by zippers 60 , 62 , and 64 . Auxiliary storage compartments 66 , 68 , 70 are provided on one side of back pack 56 . This embodiment of the present invention differs from the previously described embodiment only in that back pack 56 is vertical in aspect rather than horizontal like business case 10 of the first described embodiment.
While only two embodiments of the invention have been shown, it should be apparent to those skilled in the art that what has been described is considered at present to be a preferred embodiment of the roller wheel assembly for a tracked vehicle of this invention. In accordance with the Patent Statute, changes may be made in the roller wheel assembly for a tracked vehicle without actually departing from the true spirit and scope of this invention. The appended claims are intended to cover all such changes and modification which fall in the true spirit and scope of this invention.
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A luggage case is provided with straps or handles for carrying the case and a wheel and an extendable handle assembly for dragging or pulling the case. The wheel and extendable handle assembly is removably attachable to the case, such that it need not be carried when the case is carried by the straps or handles. The wheel and handle assembly are formed as a shell to snugly surround the luggage case. In the preferred embodiment, the case and the shell are joined by mating zippers at the bottom front and top rear edges of the assembly.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fuel expansion system for use in an internal combustion engine. Specifically, there is disclosed herein the methodology for pretreating liquid fuel wherein such pretreatment is provided by a staged, gradual heating and expansion of the fuel and its attainment of a peak heated and expanded condition by use of a novel electromagnetic induction (EMI) heating - dispersing head. After treatment of the fuel, it is injected into the engine, either at the throat of the conventional carburetor or directly into the heads of the cylinders, as is currently done with fuel injected engines.
2. Discussion of the Prior Art
The Fulenwider, Jr., U.S. Pat. No. 4,064,852, for a MICROWAVE ENERGY APPARATUS AND METHOD FOR INTERNAL COMBUSTION ENGINE, teaches a device for Vaporizing and heating liquid fuel for use in an internal combustion engine by subjecting the liquid to a radio frequency microwave energy before introduction into the engine cylinders. The approach is distinctly different from the instant invention in that Fulenwider, Jr. employs radio frequency (RF) energy treatment of the gasoline-Water-air mixture subsequent to carburetion and as the mixture is being injected into the intake manifold. Because there is a high intensity treatment of the fuel-air mixture prior to introduction to the engine proper, the instant inventor feeling that such a system lacked a good deal of inherent safety, decided to pretreat only fuel and avoid the art of Fulenwider, Jr., in all of its aspects.
Inventors Abe et al. in U.S. Pat. No. 4,450,823 employ a fuel evaporator, a PTC resistance element-heated ceramic plate, for heating the fuel and evaporating it prior to introduction into the air-fuel intake passage of an engine. The plate is an electrically heated ceramic element having a foraminous (perforated) surface through which fuel is inducted into the carburetor of the engine. Anders et al. in U.S. Pat. No. 4,742,810, disclose an ultrasonic atomizer system to atomize fuel which is to be injected into internal combustion engines. The atomizer system includes an atomizer housing having a pressure chamber into which fuel is delivered under pressure by a pump. An ultrasonic vibrator protrudes into the atomizer housing; therefore, Anders et al. provide a true fuel injector, using the ultrasonic device within the injector itself. The invention of Tuckey, U.S. Pat. No. 4,458,654, provides standard carburetion and delivers liquid fuel into a heating chamber which is colocated in the throttle body of a carburetor. Tuckey employs resistance elements, not unlike the art of Abe, but meters exhaust gases into the throttle body. Earle, U.S. Pat. No. 4,574,764 teaches a fuel vaporization method and apparatus. This disclosure details a means for using engine heat to conductively heat carburetor air-fuel mixtures after carburetion. Rawlings, U.S. Pat. No. 4,708,118, does something more than the aforesaid inventors by heating air as it is taken into the air intake manifold. A resistance heating element is situated within the air intake apparatus and a thermistor is disposed downstream of the heating element to insure that the air drawn through the air intake apparatus, into the intake manifold, is heated to a temperature within the range of 160 degrees F. to 180 degrees F. Thus Rawlings, after preheating a fuel mixture, combines it with air that is also preheated.
U.S. Pat. No. 4,715,353, issued to Koike et al. in 1987, discloses the use of ultrasonic waves for the purpose of atomizing the fuel of an internal combustion engine which is being carbureted in the normal fashion. The inventor is concerned primarily with the electronics of the atomizing system, as well as the feedback control of the circuit.
To the instant inventor, after this study of the prior art, it appeared that no previous inventor has sought to employ his staged technique of pretreating only fuel for use in an internal combustion engine. Most notably, there is no extant reference to the use of EMI heating of an expansion and dispersion element. Sonic cleaning devices are, of course, well known in the art; but the novel method of attaining ultrasonic stimulation as in the instant invention, has not come to the instant inventor through any of the extensive readings made or searches conducted in the prior art. The use of RF energy for the purposes of heating a fuel or fuel-air mixture was eschewed by the instant inventor more for reasons of practicality rather then any other reason that can only be inferred.
Many objectives and advantages of the instant invention will become readily apparent to those skilled in the art from the following disclosure and from the method taken in conjunction with the accompanying drawings, in which the salient aspects of the invention are clearly delineated. It will also be apparent to those so skilled that many modifications of the basic art forms may also be made and that practice with the invention will also give rise to several derived concepts, as well as apparatus. It is the inventor's true purpose therefore to teach a method of liquid fuel pretreatment that is conducted in a set of discrete stages so that the desired effect is achieved simply and inexpensively through the use of a durable, low cost apparatus.
SUMMARY OF THE INVENTION
The overall objective of the inventor is realized in the instant methodology of treating liquid fuel before it is inducted into the carburetor of the standard engine or the injection mechanism of a fuel-injected engine. The heat stages utilized are conductive heat, ultrasonic heating and EMI heating to properly prepare the fuel for carburetion or final stage injection. In the first stage, fuel is treated by a preheater that acquires its heat through a conductive transfer mechanism from the exhaust manifold. Second stage fuel expansion and higher vibratory fuel flow is acquired through heating which occurs concurrently during a sonic treatment phase; and the third stage of expansion consists in the compound injection and expansion through an EMI-heated dispersing head. Thereafter, having acquired the desired pressure and fully vaporized expansion, the fuel is carbureted in the conventional fashion by causing it, in the disclosed embodiment, to enter the intake throat of a conventional carburetor.
More specifically, pressurized filtered fuel is passed through the control valving mechanism which regulates the volume of fuel supplied to a fuel line heat exchanger tube. The fuel line heat exchanger tube acquires its heat by conduction from the exhaust manifold, and transfers that heat to the fuel by further conduction through the heat transfer fins located in the fuel flow line. After manifold preheating, the hot fuel is passed through the sonic tube which acquires its heat primarily by conduction from a downstream injector tube. The sonic tube transfers its heat by conducting it to the fuel through vibrating tines that are integral with the sonic tube. The tines also significantly modulate he high and low pressure fuel flow zones created by the fuel pump (impeller) and thereby induce a sonic form of wave action along the walls and nozzle of the sonic tube, thereby "scrubbing" these elements. The sonic cleaning action is, in a manner similar to the heat conduction from the injector tube, passed on down to the injector tube adding its kinetic energy to the reservoir of heat energy in the Whole injection device. The heated fuel is subsequently passed to the injector, Which acquires its heat by way of conduction heating from the dispersing head, and into the dispersing head which, similar to the upstream elements, transfers its heat to the fuel by the known physical conduction mechanisms. The hot, gaseous fuel, having thus been vaporized after its contact with the dispersing head is then removed for carburetion or other induction to the engine. The EMI means of heating the dispersing head is afforded by an oscillator-induced alternating magnetic field; the field provided by at least one pair of electromagnets disposed aside the dispersing head containment chamber and which are driven by a free running, saturable core oscillator. The EMI-field producing apparatus, novel in its design, nonetheless employs standard electric circuit building concepts that are not dealt with extensively in this disclosure.
The method and apparatus of the invention Will be better understood, With further objects and advantages thereof becoming apparent, as the reader reviews the detailed description of the preferred embodiment, while examining the drawings herein.
BRIEF DESCRIPTION OF THE DRAWINGS
Of the drawings:
FIG. 1 is an isometric illustration of the EMI apparatus with a partially exploded view of a magnet pole piece assembly;
FIG. 2a is a schematic drawing of the manifold preheater;
FIG. 2b is a schematic drawing of the sonic tube and assembly of FIG. 1;
FIG. 2c is a partial sectional view of the FIG. 1 apparatus;
FIG. 3a is an end view of the manifold preheater;
FIG. 3b is a side elevation of the manifold preheater in partial cross section;
FIG. 4a is a sectionalized side view of the sonic tube;
FIG. 4b is an end view looking into the sonic tube;
FIG. 4c is an opened sonic tube;
FIG. 5 is a partially sectionalized side view of the injection tube and dispersing head of the instant invention;
FIG. 6a is a wiring schematic of the electrical circuit used to create the magnetic field for the dispersing head; and
FIG. 6b is an electrical schematic of the oscillator circuit of the FIG. 6a.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
It has already been revealed, most notably in the Summary of the Invention, that the instant invention comprises a three stage heating system wherein fuel for an internal combustion engine is gradually heated and expanded to reach a true vapor phase immediately prior to its induction into a carburetor or fuel injection system. The first stage, preheating through the use of existing exhaust manifold heat, shall be discussed hereinafter but it is to the most salient portions of the tri-stage system that the reader's attention is first called.
Referring more particularly to FIG. 1, there are illustrated, in isometric form, the sonic and EMI field generating subassemblies 10. The sonic tube (not shown) is designed and fabricated to fit inside injector housing 20. Fuel flow into the subassemblies 10 is denoted by the stylized arrow 22. Securing injector housing 20 into the top of dispersing head EMI case 30 is cap nut 24 which encompasses an exterior flange (not shown) of the injector tube. In the securement of injector tube 20 to the top of case 30 well known methods are employed as shall hereinafter be seen, including the use of lock washers 26 and lock nut 28. Similarly detailed parts, interior to the aforesaid case assembly, shall hereinafter be disclosed.
Turning to the more prominent elements detailed in FIG. 1, there are, in addition to case 30, which is comprised of a nonmagnetic material, pole pieces 40 and air intake duct 32, which has two ports 34 arranged generally orthogonal to pole piece 40 mounts 36. The air intake ports 34 are generally in communication with the interior chamber(s) of EMI subassembly case 30. Mounts 36 are arranged transverse to the general fluid flow direction denoted earlier and are, as shown herein, mounted 180 degrees from each other on the outer periphery of the case 30. Pole piece 40, generally cylindrical in shape, has a case conforming end 40' which is ultimately positioned snuggly, as depicted in FIG. 1 by the invisible lines 41, against the cylindrical surface of the case. Pole piece 40, 40' is secured against the outer surface of the case by pole piece brackets 38 which are either, as shown herein, bolted directly to mounts 36 or, should the assembly be manufactured with fixed bracket and mount, to each other. Such means of affixing pole pieces to known geometries are well detailed in the current art and remain, for all intent and purposes, the choice of the individual inventor. Unlike the case 30, the pole Pieces 40 are composed of a ferrite or any other suitable magnetic material. The pole piece-conforming coils 42 are generally shaped in the familiar toroid from Which leads 44 are taken to the supporting driving circuitry. Coil toroids 44 are slipped over the ends of the pole pieces 40 and secured thereto by known methods. Thus, save for the emplacement of the sonic tube into the injector housing 20, the sonic tube injector - EMI dispersing unit is completed in the preferred teaching of this disclosure.
Having viewed the most salient aspect of this tri-stage fuel treatment system, the reader's attention is now drawn to FIGS. 2a through 2c, wherein the three elements relating to the three stages of fuel treatment will be discussed FIG. 2a is a schematic drawing showing preheater 50 attached to or mounted on exhaust manifold 52. Greater detail will be given to this device in the discussion of FIGS. 3a and 3b. Suffice it to say that fuel enters the preheater 50 in the direction indicated by arrow 23 and exits as 23' . It moves downstream in its heated and somewhat expanded condition into sonic tube 60. There it encounters tuning forks 62 of sonic tube 60 and is further conditioned by heat that is being conducted to the tube 60 through injector housing 20. After the fuel is conditioned by mechanisms that will become apparent hereinafter, it is expelled through injector nozzle 64 into the dispersing head 70. Meanwhile dispersing head 70, comprised of a magnetic material such as stainless steel, and residing inside of nonmagnetic case 30 (not shown) has been subjected to a rapidly fluctuating magnetic field provided by transversly disposed magnetic subassemblies 40, 42. The rapid reversal of the magnetic field, as is generally employed in this technique of excitation by electromagnetic induction (EMI), causes the dispersing head 70 to heat intensely due to hysteresis losses. The heat from the dispersing head is conducted through dispersing head mount 72 (not shown in FIGS. 2a-2c), via its own case and holder 73 to the injector housing 20. Thus, as previously stated, injector tube 20 draws its heat from the magnetically induced heating effects in the dispersing head 70. More specifically, and with reference to FIG. 2c, the injector housing 20 is connected by the aforementioned apparatus (24, 26, 28) directly to the dispersing head 70. Sonic tube 60, a separate and distinct unit is inserted into injector housing 20 and is, in turn, heated by the injector housing. The remaining components disclosed in FIG. 2c comprise the sealing gasket 27 which is interposed between the mount flange 74 and case 30, the mount holder 73 for the dispersing head 70 and, the plurality of foramens 71 that act as exits for the heated fuel so that it might be drawn, with the air entering through ducts 34, into the interior of the engine proper 100. It can now be seen through the series of drawings in FIGS. 2a through 2c that the fuel 23 flows into the exhaust manifold heater 50, is heated and preconditioned for introduction into the dispersing head 70 -heated injector tube 20 by first encountering sonic apparatus 60, 62. The pulsing pattern of the fuel pump-driven fuel causes a sonic pattern to be established in the sonic tube by interaction with tuning forks 62. This ultrasonic vibration, in combination with the heated sonic tube, causes a further conditioning of the fuel and an evening of the fuel pump pulsation characteristic so that the fuel is further expanded and given a greater flow continuity. The sonic oscillations within the fuel stream act upon the walls of the sonic tube, injector tube and injector nozzle 64 With a cleansing effect. Thereafter, the pretreated fuel is injected into the dispersing head 70 Which is continuously subjected to a rapidly fluctuating magnetic field operating in a frequency band ranging from audio frequency (AF) to extremely high frequency (EHF). After final heating in the dispersing head mechanism 70, the fuel is expelled in a fully vaporized state through the foraminous dispersing head 70 by way of the holes or foramens 71 therein and into the intake system 100 of the engine.
FIGS. 3a -3b and FIGS. 4a -4c are used to explain the more detailed elements of the manifold preheater and sonic tube, respectively. Referring more particularly to the former, the manifold preheater, there is shown in FIG. 3a an end view of a preferred embodiment for this device. The reader will note that it is merely a block of heat-conducting material 50 having a chamber 51 therethrough in which is inserted, or built integrally therein, a heat-conductive divider network 54. The inventor terms the divider network 54 heat exchange fins, but those of ordinary skill will readily discern that any suitable heat transfer mechanism may be employed. The preferred metal for constructing the flanged 50' base or housing 50 is stainless steel. Fuel line couplings are made at 57 and are better understood by reference to FIG. 3b. Therein, the reader will note that flange 50' is mounted on exhaust manifold 52, the arrows within the exhaust manifold denoting the usual flow of exhaust gases. Heat exchange fins 54 are displayed in the sectionalized portion of FIG. 3b and it may be seen that fuel line coupling 57 abuts the heat exchange chamber 55. Current state of the art provides many modes for embodying the fuel line connection, heat exchange unit mounting and exhaust manifold connection mechanisms. For example, the instant inventor suggests that separate fuel line couplings 57 be welded at their connection with housing 50; housing 50 flanges 50' be either bolted or welded to the exhaust manifold section 52 or, in the alternative the entire unit comprising couplings 57, housing 50 and exhaust manifold section 52 be manufactured as an integral unit for connection by traditional means to an engine exhaust manifold.
The second stage of fuel treatment is conducted in sonic tube 60. Referring particularly to FIG. 4a, there is depicted in sectionalized schematic view a segment of the sonic tube 60. Four tuning forks 62 are secured by each of their singular bases 62' to the interior Wall of sonic tube 60, With the tines of the forks radiating inwardly. Fuel flow is denoted by the heavy barbed arrows entering from the right hand side and indicated "Fuel Flow". Schematic depiction is made of the fuel flow at points when the liquid is exhibiting the effect of fuel pump compression, denoted FC and the lack of compression or rarefaction phase, denoted FR, between the compression peaks. The staccatic fuel flow impinges on tuning forks 62 sending them into a vibrating state. The nature of the tuning forks, based upon their particular design and composition, establishes a vibrating pattern (at the forks' 62 tuning frequency) in the fuel flow which modulates the wave at FC and at FR; thus, a consistent sonic wave pattern is established within the tube 60 lending greater continuity to the fuel flow and affording a cleansing action in the injector tube 20 and injector nozzle 64. FIG. 4b depicts the end view of sonic tube 60 and the reader's attention is called to the seam 61 which may be realized by butt welding or a similar process. FIG. 4c is an illustration of the FIG. 4`b device simply "unrolled". The inventor suggests this method of construction of the sonic tube as it will allow accurate emplacement of the tuning fork 62 mechanisms to the shell of the tube and thereafter lend itself to a rolling so that longitudinal margins 61/1 and 61/2 may be brought together as in FIG. 4b. Other methods are also available for mounting the inwardly radiating tuning forks 62, explanation of the techniques of which would digress needlessly from the scope of this disclosure.
The assembled injector 20 - dispensing head 70 device is shown in a partially cross sectional illustration in FIG. 5. The direction of fuel flow is depicted by arrow 22 and it can be seen that sonic tube 60 is emplaced in injector housing 20 in the direction of fuel flow. All previously described apparatus relating to the mounting of dispensing head 70 to case 30 is clearly depicted herein. Injector head 64 discharges directly, through head mount 72, into the interior of the foraminous dispensing head 70. Since the dispensing head 70 is concurrently subjected to a high intensity EMI field, it, its holder 73 and all attached apparatus, such as the injector housing 20 with installed sonic tube 60, are heated intensely and conduct the heat throughout the various assemblies. It is the dispensing head, however, that attains the greatest heat intensity and it is at this point that the preheated fuel, already in a nebulized state, is vaporized and expelled through foramens 71 into case 30 for induction into the main intake apparatus 100 of the engine.
FIG. 6a is a schematic that will be recognized by those having skill in the field of automotive electronics. Essentially, a free-running, saturable core oscillator 80 is connected to an automotive power production and regulation system 90. When switch SW is engaged, oscillator 80 commences operation and the EMI field coils 42 are alternatingly energized at the frequency established by the basic oscillator 80. FIG. 6b is an electronic schematic of oscillator 80 taken at 6b --6b. This depiction, of a common oscillator of the saturable core type, yields an output 81 characterized as the alternating square wave. Again, those having skill in the field of electronics will recognize that the inventor has chosen the saturable core oscillator for powering the EMI field transformers for several reasons. It is known, for example, that the frequency of oscillation is determined by the battery voltage (here, standard 12 volt battery), the number of turns in the portion of the winding which feeds the emitters of the transistors, the flux density at which saturation occurs, and the cross-sectional area of the core. However, once the oscillator has been constructed, battery voltage is the only frequency governing parameter which requires consideration, the others being fixed by the number of turns placed on the core, and the nature and geometry of the core material. This type of oscillator is very efficient, with efficiencies often exceeding 90%. A further enhancement, low power drain, is acquired because an "off" transistor has high collector voltage but a current of practically zero and, when fully "on" , (the other operating state of the transistor), collector current is high but collector voltage is extremely low. Thus, in either state, the product of collector voltage and current (power) yields low wattage dissipation in the collector-emitter diode.
From the foregoing, it will be apparent that the instant invention provides a unique protocol for the pretreatment of fuel to be used in an internal combustion engine because of the invention's unique embodiment of a heating-sonic cleaning device in conjunction with an EMI field-heated dispersing head. The use of an early stage manifold conduction heater is made in the interest of efficiency and expediency and is an adjunct to the aforementioned elements. Those of ordinary skill, particularly those skilled in this art, will recognize that such a preheating stage is not necessary and, indeed, in many instances contraindicated for safety reasons. Similarly, although various embodiments have been described and depicted herein, it will also be apparent to those skilled in this art that various modifications, additions, substitutions, etc. may be made without departing from the spirit of the invention, the scope of which is more clearly defined by the claims appended hereto.
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A self cleaning, fuel expansion system for an internal combustion engine. Methods are applied through apparatus for pretreatment of liquid fuel prior to the fuel usage by an internal combustion engine, whether such usage conceives of carburetion or direct fuel injection. A staged, gradual heating and expansion of the fuel is afforded by: first, a conduction-type heater that is essentially a conduit taking its heat directly from the exhaust manifold of an engine; second, a sonic heating conduit that contains a tuning assembly therein that is responsive to the pulsating fuel pump output and which responds by imparting a modulated vibratory pattern to the fuel passing therethrough, while heating the fuel by both the vibrations imparted and conduction of heat from another system part; and third, passing nebulized fuel from an injector into a foraminous dispersing head that is concurrently heated by a process of electromagnetic induction (EMI), thereby completely vaporizing the fuel immediately prior to its induction by the engine. The sonic tube heater-cleaner, as well as the EMI-heated dispersing head work in conjunction to provide a continuously high pressure fuel flow of vapor phase fuel to any form of combustion engine.
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BACKGROUND OF THE INVENTION
A. Field of the Invention
This invention relates to surface controlled subsurface safety valves utilized to control flow at a subsurface location in a well.
B. The Prior Art
Well pressure may assist closure of a surface controlled subsurface safety valve as disclosed in U.S. Pat. No. 3,703,193 to Raulins. However, as well pressure approaches zero such a safety valve becomes depth sensitive. As well pressure approaches zero, spring force, or other inherent resilient urging means, is relied upon to close the valve.
Some surface controlled subsurface safety valves, such as disclosed in U.S. Pat. No. 3,696,868 to Taylor, include a balance pressure chamber. Valve closure of such a safety valve may be assisted by pressurizing the balance pressure chamber. However, heretofore, designing a subsurface safety valve having a balance pressure chamber so that valve closure may be assisted by well pressure has resulted in increasing the depth sensitive limitations of the valve as the balance pressure approaches zero, vis a vis a valve without a balance pressure chamber. Also, heretofore, designing a subsurface safety valve having a balance pressure chamber so that a greater force tending to close the valve is produced when there is approximately the same pressure within both the balance pressure chamber and the control pressure chamber has resulted in well pressure tending to maintain the valve open.
OBJECTS OF THE INVENTION
It is an object of this invention to provide a surface controlled subsurface safety valve wherein valve closure may be assisted by the greater of well pressure and balance pressure.
It is another object of this invention to provide a surface controlled subsurface safety valve wherein well pressure may assist valve closure without increasing the depth limitations of the valve as balance pressure approaches zero.
It is another object of this invention to provide a surface controlled subsurface safety valve wherein the force effectiveness of balance pressure, which force tends to close the valve, is increased over the force effectiveness of control pressure and well pressure does not resist closure.
These and other objects and features of advantage of this invention will be apparent from the drawings, the detailed description and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings, wherein like numerals indicate like parts, and wherein an illustrative embodiment of this invention is shown:
FIG. 1 is a quarter-sectional view of a surface controlled subsurface safety valve, with the valve open;
FIG. 2 is a quarter-sectional view of the subsurface safety valve of FIG. 1 with the valve closed due to balance pressure assistance;
FIG. 3 is a slightly enlarged quarter-sectional view of the valve of FIG. 1 showing the valve closed due to well pressure assistance;
FIG. 4 is a partial quarter-sectional view showing the mounting for the ball valve member of the subsurface safety valve of FIGS. 1, 2 and 3; and
FIG. 5 is a schematic illustration of a well installation incorporating the safety valve of FIGS. 1 through 3.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
An important criterion that industry has selected for surface controlled subsurface safety valves is that valve closure be failsafe. Regardless of pressure conditions at the valve, the surface controlled subsurface safety valve should close upon reduction of control fluid pressure. If present, well pressure should assist valve closure and should not retard valve closure. Valve closure may also be assisted by pressure balancing fluid. The pressure balancing fluid communicates between the subsurface valve and the surface controls. It balances the hydrostatic head of control fluid pressure which is effective within the valve to retard valve closure. If desired, the pressure balancing fluid may be pressurized to provide a positive force to close the valve. Additional balance fluid pressure assistance for valve closure may be obtained by having a balance piston area which is larger than the control piston area. However, providing a balance piston area which is larger than the control piston area should not render the safety valve more depth sensitive vis a vis subsurface safety valves without a balance pressure chamber, as the balance pressure approaches zero and such a design should not result in well fluid pressure retarding valve closure.
The surface controlled subsurface safety valve of this invention obtains these desirable features. It closes with the assistance of the greater of well fluid pressure and balance fluid pressure. Additional balance pressure assistance for valve closure is attained without well pressure retarding valve closure and without increasing the depth sensitive limitations of the valve, via a vis, subsurface safety valves with only a single control conduit, as the balance fluid pressure approaches zero.
A well installation incorporating the surface controlled subsurface safety valve of this invention is schematically illustrated in FIG. 5. The well is cased with the normal casing string 10. Through the casing string 10 extends a tubing string 12. Fluids from a producing formation (not shown) may be confined to within the tubing string 12 by sealing off the annulus between tubing string 12 and the casing 10 with packer means 14. Fluid flow through the tubing string 12 may be controlled at a subsurface location by subsurface safety valve 16 (shown in dotted form in FIG. 5). At the well surface, flow through the tubing string 12 may be controlled by surface valves 18 and 20. To control the subsurface safety valve 16 from the surface, control conduit means 22 and balance conduit means 24 extend between the valve 16 and the surface. At the surface, fluid is pressurized or depressurized and pumped into one of control conduit means 22 and balance conduit means 24 by operating manifold 26. Pressurizing control conduit means 22 opens the subsurface safety valve 16. Depressurizing control conduit means 22 permits closure of the subsurface safety valve 16. Closure of the subsurface safety valve 16 is assisted by the greater of well fluid pressure at the location of the subsurface safety valve 16 and balance fluid pressure within balance conduit means 24.
The detailed structure of the surface controlled subsurface safety valve 16 is illustrated in FIGS. 1 through 3. The illustrated subsurface safety valve 16 is a wire line retrievable, tubing safety valve. If desired, the valve could be adapted, by those skilled in the art, to render it a tubing retrievable tubing safety valve or it could be adapted for use with pump down equipment.
The safety valve 16 includes a valve housing 28 for defining the controlled subsurface flow path, closure means for controlling flow through the defined flow path, control pressure responsive means for moving the closure means to a position opening the subsurface flow path when control conduit means 22 is pressurized, and means responsive to the greater of well fluid pressure and pressurized fluid within balance conduit means 24 for assisting movement of the closure means to a position preventing flow through the subsurface flow path.
Valve housing 28 defines the controlled subsurface flow path. It has a bore 30 extending therethrough through which fluids may flow and is formed from interconnected tubular sections 28a, 28b, 28c, and 28d. Carried on valve housing 28 is seal means 32 for sealing between valve housing 28 and the tubing string 12. When the subsurface safety valve 16 has been positioned in the tubing string 12 and seal means 32 rendered effective, fluid flow through the tubing string 12 from below the subsurface safety valve 16 is confined to the bore 30 through the valve housing 28.
Closure means controls flow through the housing bore 30. The closure means is disposed in the housing bore 30 and adapted for movement between positions opening and closing the bore 30. Closure means includes ball valve means 34 and annular valve means 36.
Operator means 38 moves the closure means, including ball valve means 34 and annular valve means 36, between their positions opening and closing the housing bore 30. Operator means 38 is disposed in the housing bore and axially movable therein between a first and second position. When operator means 38 is in its first position, closure means closes the housing bore 30 to fluid flow. When operator means 38 is in its second position, closure means opens the housing bore 30 to fluid flow.
The closure means is designed for a sequential opening so that pressures may be equalized across ball valve means 34 before it is rotated towards its bore opening position. The mounting means for ball valve means 34 includes lost motion rotation means. Initial axial movement of operator means 38 from its first position to its second position opens annular valve means 36, axially moves ball valve means 34, but does not result in rotation of ball valve means 34. Well fluids communicate through the open annular valve means 36 around the still closed ball valve means 34. This communication of well fluids will equalize fluid pressures across ball valve means 34. Thereafter, movement of operator means 38 to its second position is continued. Operator means 38 in turn moves ball valve member 34 to its full bore opening position.
Annular valve means 36 may be associated with operator means 38 and is axially movable therewith. It includes a movable metal-to-metal seating surface 40 which sealingly engages a complementary metal-to-metal sealing surface 42 formed on tubular housing section 28c. When these metal-to-metal surfaces 40 and 42 are engaged (as shown in FIGS. 2 and 3) fluid communication around ball valve means 34 is prevented. When these metal-to-metal sealing surfaces 40 and 42 are spaced (as shown in FIG. 1), fluid communication around ball valve means 34 is permitted. Well fluids communicate between the housing bore 30 above ball valve means 34 and the housing bore 30 below ball valve means 34 through port means 44 in operator means 38.
Bal valve means 34 is mounted for axial and rotational movement within the housing bore 30. Ball valve means 34 is carried by finger means 46 which depend from annular valve means 36. Finger means 46 include opposed pin means 48 which project into two pivot bores 50 formed on opposite sides of ball valve means 34. Axial movement of ball valve means 34 within the housing bore 30 is caused by the engagement of opposed pin means 48 with pivot bore means 50 and the co-axial movement of finger means 46 and operator means 38. The rotation of ball valve means 34 is due to the engagement of pivot pin means 52 formed on control frame 54 with pivot slot means 56 formed in ball valve member means 34. Control frame 54 is disposed in the housing bore 30. During the initial axial movement of operator means 38 from its first position to second position, control frame 54 undergoes a corresponding axial movement from its first upward position to its second downward position. Because of this corresponding axial movement of control frame 54, no moment arm is imparted by pivot pin means 52 to pivot slot means 56. Therefore, ball valve means 34 remains in its bore closing position during this initial axial movement of operator means 38. Upon additional axial movement of operator means 38, control frame 54 remains stationary. However, ball valve means 34 continues its axial movement due to the engagement of opposed pin means 48 with pivot bore means 50. Pivot pin means 52 imparts a moment arm to ball valve means 34 due to its engagement with pivot slot 56. This moment arm rotates ball valve means 34 to its full bore opening position.
Ball valve means 34 includes an outer sealing surface 58 for sealing with an annular seat 60 formed on annular valve member means 36 when ball valve member means 34 is in its bore closing position. It also includes a passage 62 extending therethrough for providing a full bore opening flow path through the housing bore 30 when ball valve means 34 is in its bore opening position.
To provide a failsafe, normally closed, subsurface safety valve 16, means, such as spring 64, resiliently urge operator means 38 to its first position. Spring means 64 is disposed around operator means 38 between a shoulder 66 formed by tubular housing section 28c and a shoulder 68 carried by operator means 38.
The subsurface safety valve 16 includes control pressure responsive means for moving operator means 38 to its second position. The control pressure responsive means includes control pressure chamber means 70 formed between the valve housing 28 and operator means 38. The control pressure responsive means moves the operator means 38 to its second position, wherein the closure means opens the housing bore 30, when control pressure chamber means 70 is pressurized a sufficient amount.
Control pressure chamber means 70 is defined, in part, by the valve housing 28, operator means 38, a first seal means 72 and a second seal means 74. First seal means 72 is carried by the tubular housing section 28a and seals between the valve housing 28 and operator means 38. First seal means 72 has a first seal effective area which is defined by the circular cross-sectional area within its inside diameter. Second seal means 74 is carried by operator means 38 and seals between valve housing 28 and operator means 38. It has a second seal effective area. The second seal effective area is greater than the first seal effective area of first seal means 72 and is defined by the circular cross-sectional area within the outside diameter of seal means 74.
The pressure of well fluids within the housing bore 30 above the closure means will be effective across the first seal effective area and will produce a force tending to move operator means 38 towards its second position. This produced force will be equal to the product of the pressure of these well fluids times the first seal effective area.
Pressurized control fluid within control pressure chamber means 70 is effective across the control piston area defined by the second seal effective area minus the first seal effective area. Pressurized control fluid within control pressure chamber means 70 produces a force tending to move operator means 38 to its second position. The force produced by pressurized control fluid within control pressure chamber means 70 is equal to the product of the pressure of the control fluid times the control piston area of control pressure chamber means 70.
Control fluid is communicated to control pressure chamber means 70 from the surface by control conduit means 22. As shown, conduit means 22 may terminate at a connector means 76 formed on the tubing string 12 adjacent to the location of control pressure chamber means 70 therein. Control fluid communicates between conduit means 22 and control pressure chamber means 70 through port means 78 formed in the tubing string 12 and port means 80 formed in the valve housing 28. Spaced seal means 82 and 84 carried around valve housing means 28 confine the control fluid to communicating between control conduit means 22 and control pressure chamber means 70.
In addition to the force generated by the resilient urging spring means 64, the safety valve 16 includes additional means for moving operator means 38 to its first position. This additional moving means is responsive to the greater of the pressure of well fluids and pressure balancing fluid. When pressure balancing fluid is effective upon the additional moving means, a resultant force tending to move operator means 38 to its first position is produced even though control conduit means 22 and balance conduit means 24 are pressurized an equal amount. The resultant force is obtained because the balance piston area across which the pressure balancing fluid is effective is greater than the control piston area. The net well pressure force does not oppose the resultant force due to pressure balancing fluid. When well fluid pressure is effective upon the additional moving means, the depth sensitive limitations of the subsurface safety valve 16, vis a vis subsurface safety valves with a single control conduit, are not increased, even as the pressure within balance conduit means 24 at the subsurface safety valve 16 approaches zero.
The additional means for moving the operator means 38 to its first position includes floating piston means 86 and balance pressure chamber means 88.
Floating piston means 86 is disposed between operator means 38 and the valve housing 28. It includes third seal means 90 and fourth seal means 92. Third seal means 90 seals between floating piston means 86 and operator means 38. It has a third seal effective area defined by the circular cross-sectional area within its inside diameter and which is less than the first effective seal area of seal means 72. Fourth seal means 92 seals between floating piston means 86 and the valve housing 28. It has a fourth seal effective area which is greater than the seal effective area of first seal means 72 and less than the seal effective area of second seal means 74. The fourth seal effective area is defined by the circular cross-sectional area within the outside diameter of fourth seal means 92.
Balance pressure chamber means 88 is formed between operator means 38 and valve housing 28. It is defined, in part, by second seal means 74 and floating piston means 86. The balance piston area is defined by the second seal effective area of second seal means 74 minus the third seal effective area of third seal means 90. The balance piston area is therefore greater than the control piston area.
Pressurized control fluid communicates between operating manifold 26 and balance pressure chamber means 88 through balance conduit means 24. Connector means 94 is attached to the tubing string 12 adjacent to the location of balance pressure chamber means 88 therein. The lower end of balance conduit means 24 is attached to connector means 94. Hydraulic balance fluid communicates between balance conduit means 24 and balance pressure chamber means 88 through port means 96 extending through the tubing string 12 and port means 98 in valve housing means 28. Seal means 84 and 32 seal between the valve housing 28 and the tubing string 12 to confine the communication of balancing fluid to between balance conduit means 24 and balance pressure chamber means 88.
When the pressure of well fluids within the bore 30 of the subsurface safety valve is greater than the pressure of balance fluid within balance pressure chamber means 88, the well fluid pressure produces a force tending to move operator means 38 to its first position. The well fluids communicate through port means 44 in operator means 38 and are effective across the fourth effective seal area of fourth seal means 92. Since the fourth seal effective area is greater than the first seal effective area of seal means 72, the net force of well fluid pressure within the bore 30 is equal to the product of the pressure of these well fluids times the annular area defined by the fourth seal effective area of seal means 92 minus the first seal effective area of first seal means 72.
Floating piston means 86 is axially movable within the subsurface safety valve 16. Stop shoulder means 100 formed on valve housing 28 renders effective the third seal effective area of seal means 90 when balance fluid pressure is greater than well fluid pressure. Stop shoulder means 102 formed on the operator means 38 renders effective the fourth seal effective area of seal means 92 when well fluid pressure is greater than pressure balance fluid pressure. One end 86a of floating piston means 86 engages stop shoulder means 100 when the balance fluid has the greater pressure while the other end 86b of floating piston means 86 enages stop shoulder means 102 when the well fluids have the greater pressure. The stop shoulder 100 and 102 are spaced so that operator means 38 may be moved to its second position without floating piston means 86 preventing such movement due to confinement between stop shoulder means 100 and 102.
In operation, the surface controlled subsurface safety valve 16 of this invention controls fluid flow through a well at a subsurface location in response to surface controls.
To open the subsurface flow path through the housing bore 30, control fluid in control conduit means 22 is pressurized by operating manifold 26. The pressurized control fluid from control conduit means 22 communicates to control pressure chamber means 70. The pressurized control fluid within control pressure chamber means 70 is effective across the control piston area. The pressure times the control piston area produces a force tending to move operator means 38 downwardly to its second position. when the produced control force is great enough, operator means 38 is moved downwardly. Closure means undergoes a corresponding axial movement and is moved to its position opening the subsurface flow path (See FIG. 1).
To close the subsurface flow path through the housing bore 30 with balance fluid pressure assistance, operating manifold 26 depressurizes control fluid within control conduit means 22 and pressurizes blanace fluid within balance conduit means 24. The resilient urging force of spring means 64 already tends to move operator means 38 to its first position. The pressure force within balance pressure chamber means 88 provides an additional force tending to move operator means 38 to its first position. When balance pressure chamber means 88 is pressurized, floating piston means 86 moves axially unitl its end 96a engages stop shoulder means 100. The third seal effective area of third seal means 90 is thereby rendered effective. With the third seal area rendered effective, the pressure of fluid within balance pressure chamber means 88 produces a force tending to move operator means 38 to its first position. Generally, the pressure within balance pressure chamber means 88 and the pressure of fluid within control pressure chamber means 70 will be approximately equal. However, since the balance piston area is greater than the annular control piston area, the resultant force of control fluid and balance fluid tends to move operator means 38 to its first position. If desired, balance pressure chamber means 88 may be pressurized to an amount greater than the pressure of fluid within control pressure means 70. An additional force is thereby provided to move operator means 38 t0 its first position. When the sum of the force of spring means 64 and of pressurized balance pressure chamber means 88 is sufficient, operator means 38 will be moved to its first position. It in turn, moves closure means to its position closing flow through the housing bore 30. The metal-to-metal sealing surfaces 40 and 42 for annular valve means 36 are engaged. The ball valve means 34 is rotated to its position preventing flow through the subsurface safety valve 16 (See FIG. 2).
Even though the balance piston area is greater than the control piston area, the net force of well fluid pressure does not retard valve closure. A first well pressure force, which does tend to retard valve closure, is produced across the first seal effective area. A second, opposing well pressure force is produced across the fourth seal effective area. Since the fourth seal effective area is greater than the first seal effective area, the net well pressure force tends to assist valve closure and never acts to retard valve closure.
Valve closure will be assisted by well fluid pressure whenever it is greater than balance fluid pressure. The well fluids will communicate through port means 44 and will act across floating piston means 86. Floating piston means 86 will be moved axially within the safety valve 16 by well fluid pressure until its upper end 86b engages operator stop shoulder means 102. When floating piston means 86 is so engaged, the fourth seal effective area of fourth seal means 92 is rendered force effective. Well fluids within the housing bore 30 produce a force euqal to the product of the well fluid pressure times the fourth seal effective area of fourth seal means 92. That produced force tends to move operator means 38 to its first position. Well fluids are also effective across the first seal effective area of first seal means 72. The force produced across the first seal means 72 tends to move operator means 38 to its second position. However, because the fourth seal effective area is greater than the first seal effective area, the net force produced by well fluid pressure tends to move operator means 38 to its first position. When a sufficient force has been produced by the sum of the well fluid pressure force and the force of spring means 64, operator means 38 is moved to its first position. It, in turn, moves the closure means to its position preventing flow through the subsurface safety valve (see FIG. 3).
Well fluid pressure assistance for closure of the subsurface safety valve 16 does not increase the subsurface safety valve's depth sensitiveness, vis a vis present subsurface safety valves which do not have a balance pressure chamber, even as the pressure of fluid within balance chamber means 88 appproaches zero. Subsurface safety valves become depth sensitive due to the hydrostatic pressure of control fluid within a control conduit being effective across a control piston. The pressure of well fluids, for a subsurface safety valve without a balance pressure chamber, would also be effective across the control piston and produce a force tending to counter the hydrostatic pressure force. For the subsurface safety valve 16 of this invention, the hydrostatic pressure of control fluid is also effective across the control piston area (e.g., the second seal effective area minus the first seal effective area). The net well pressure force for the subsurface safety valve 16 is produced by well fluid pressure effective across the fourth seal effective area minus the first seal effective area. With this net well pressure force, the depth sensitive limitations of the safety valve 16 are not increased, vis a vis safety valves without a balance pressure chamber, even as the balance fluid pressure approaches zero.
From the foregoing, it can be seen that the objects of this invention have been obtained. A surface controlled subsurface safety valve has been provided wherein valve closure is assisted by the greater of well fluid pressure and balance fluid pressure. Balance fluid pressure is effective across an area greater than the control piston area without well pressure retarding movement of the safety valve to its closed position. Well pressure assists valve closure without increasing the depth sensitiveness of the subsurface safety valve, vis a vis present subsurface safety valves without balance pressure assistance for closure, even as the balance pressure approaches zero. Thus, the best of two desired operating conditions is obtained.
The foregoing disclosure and description of this invention are illustrative and explanatory thereof, and various changes in the size, shape, and materials, as well as the details of the illustrated construction, may be made within the scope of the appended claims without departing from the spirit of the invention.
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Disclosed is a surface controlled subsurface safety valve wherein the greater of well pressure and balance pressure assists in closing the safety valve. Well pressure assist for valve closure is obtained without creating additional depth sensitive limitations as the balance pressure approaches zero. Balance pressure assist for valve closure is obtained without well pressure tending to maintain the valve open. This abstract is neither intended to define the scope of the invention, which, of course, is measured by the claims, nor is it intending to be limiting in any way.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a material for making a fuse which generates a small quantity of heat, which has a long useful service life and which is suitable for use in a circuit where a relatively large current flows.
2. Prior Art
Tubular or planar fuses made of zinc have been widely used hitherto in various circuits in automobiles. A demerit of the fuse made of zinc is its short useful service life although the fuse has such a merit that it generates a small quantity of heat before it breaks the circuit by melt-down and during use under a normal current-conducting condition. With a view to solve the above problem, a fuse made of a zinc-copper alloy containing less than 5% of copper added to zinc has been proposed, as disclosed in JP-A-No. 53-138918. However, it has been pointed out that, when such a fuse is connected in a circuit where a relatively large current of, for example, 20 amperes or more flows, especially when used in a circuit where an inrush current flows due to repeated on-off of a motor, the alloy particles tend to become excessively large due to repeated thermal expansion and contraction, resulting in development of cracks. Thus, the proposed fuse made of such a zinc-copper alloy has a limited useful service life.
Therefore, a fuse made of a copper alloy having a high melting point, as disclosed in JP-A-No. 58-163127, is now commonly used in a circuit where a large current flows. However, the fuse made of such a copper alloy is disadvantageous in that it generates a large quantity of heat although it has a long useful service life.
Generally, the circuit breaking action of a fuse made of a metal takes place when an area of the fuse heated by the joule heat melts down at the melting point of the metal, thereby breaking the circuit. It can be readily understood that a fuse made of a high-melting metal imparts more thermal damage to an adjacent part than a fuse made of a low-melting metal. That is, when a fuse made of a high-melting metal is connected in a circuit using an insulated wire for conducting current, the circuit-breaking melt-down area of the fuse generates more heat than the remaining area even under a normal current-conducting condition, and the portions of the insulation covering (whose typical material is polyvinyl chloride) of the wire adjacent to the fuse are heated by the heat transmitted from the circuit-breaking melt-down area of the fuse, resulting in a promoted degradation of those portions of the insulation covering. Further, it is the recent tendency that automobiles of front-engine front-drive design are gaining popularity, and the output of engine becomes higher and higher. Because of the above tendency, the environment of the engine room becomes increasingly severe, and the environmental temperature is rising more and more. Therefore, it has been demanded to suppress the undesirable temperature rise of heat-generating parts even by an amount of 1° C. at the least.
As means for satisfying the demand for minimizing the quantity of generated heat as well as the demand for ensuring a long useful service life, there is a proposal according to which a metal having a relatively low melting point, for example, silver or aluminum, is used to make a fuse. However, a fuse made of silver has the problem of high cost. Also, when aluminum is used to make a fuse, aluminum forms a tight film of its oxide, and a bridge of alumina may remain in a non-melted state even when the fuse is heated due to flow of an overcurrent until finally its melting point is reached. Further, because aluminum is easily corroded even when its oxide film may not be formed, electrolytic corrosion tends to occur between the fuse and a connection terminal or a wire to which the fuse is connected. Therefore, silver and aluminum are not suitable as the material for making fuses, and those made of silver and aluminum are now scarcely put into practical use.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a material for making a fuse which generates a small quantity of heat, which has a long useful service life, which can be manufactured at a low cost and which is suitable for use in a circuit where a relatively large current flows.
The inventor conducted research and studies in an effort to solve the prior art problems described above and found out that a fuse made of aluminum plated with copper or a rollable aluminum alloy plated with copper generates a small quantity of heat, has a long useful service life and exhibits a sharp circuit-breaking melt-down characteristic even when it is connected in a circuit conducting a relatively large current.
That is, the present invention is featured by the fact that aluminum or a rollable aluminum alloy having a copper plating is used as a material for making a fuse.
The required thickness of the copper plating is only about 1 to 5 μm. Such a copper plating is easily deposited on one surface or both surfaces of the circuit-breaking melt-down area of the fuse by any one of known means including electroplating, vacuum evaporation and bonding by cold rolling. The temperature rise of the fuse can be further suppressed by depositing a tin plating on the copper plating.
The rollable aluminum alloy preferably used to make the fuse of the present invention is, for example, Al:A1200 or Al:A2218 specified as a material suitable for making sheets, bars, plates, strips, etc. in JIS (Japanese Industrial Standards).
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of a sample of a fuse made of a material embodying the present invention.
FIG. 2 is an exploded perspective view of an assembly consisting of the fuse sample shown in FIG. 1 and an associated terminal member.
FIG. 3 shows the structure of a device used for testing the useful service life and temperature rise of the assembly shown in FIG. 2.
FIG. 4 is a graph showing a current waveform used in a motor current cyclic test on the assembly shown in FIG. 2.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a plan view of a sample of a fuse A obtained by stamping. As shown in FIG. 1, the fuse sample A consists of an elongate body 2 having a length L 2 and a width W 2 and a pair of conductor connecting portions 3 extending in opposite directions from the body 2 and having a width larger than that of the body 2. The body 2 includes a central circuit-breaking melt-down portion 1 having a length L 1 smaller than L 2 and a width W 1 smaller than W 2 . Various materials including that of the present invention as shown in Table 1 were used to form such fuse samples A having a thickness of 0.4 mm, and the dimensions of L 1 , W 1 , and L 2 , W 2 were adjusted to meet a current rating of 45 amperes. The unit of dimensions in the parentheses shown in FIG. 1 is millimeter.
Each of such fuse samples A was bent into a symmetrical U-shape as shown in FIG. 2 and was assembled with a terminal member 4 having a pair of elastic conductor-holding arms 6 extending from a base 5. The assembly B shown in FIG. 2 was fixed in a plastic casing 7 as shown in FIG. 3, and a pair of tab terminals 8 having conductors 9 crimped thereto were fitted into the plastic casing 7 to test the fuse sample A.
The fuse sample A was subjected to two kinds of tests, that is, a motor current cyclic test for determining the useful service life of the fuse sample and a temperature rise test for measuring the temperature rise due to heat generated from the fuse sample under a normal current-conducting condition.
In the motor current cyclic test, the sample was placed in an environment maintained at a temperature of 80° C., and a current waveform as shown in FIG. 4 was repeatedly supplied to the sample over 200,000 cycles to check whether or not the circuit-breaking melt-down occurred during this endurence test.
In the temperature rise test, a current of 30 amperes was continuously supplied to the sample kept at a temperature of 80° C., and a copper-constantan thermocouple (not shown) fixed to the rear surface of the conductor-crimped part C shown in FIG. 3 was used to measure the temperature rise of the sample.
The results of these tests are shown in Table 1. It will be seen in Table 1 that the fuse made of the material according to the present invention shows a temperature rise less than that of conventional fuses and has an excellent durability. Especially, the fuse having a tin plating in addition to the copper plating shows a further suppressed temperature rise.
The thickness of the copper plating and that of the material of the fuse samples of the present invention were changed, and similar tests were conducted on such fuse samples. The test results are shown in Table 2. It will be seen from Table 2 that a rollable aluminum alloy, when used in lieu of the aluminum, can also be preferably employed as the material of the fuse which generates a small quantity of heat, which has a long useful service life and which is suitable for use in a circuit where a relatively large current flows.
TABLE 1__________________________________________________________________________Sample TemperatureNo. Sample Cyclic test rise (°C.)__________________________________________________________________________ Zn Melt-down occurred1 after about 2,000 28.5-32.3 cyclesPrior Zn containing 2% of Cu Melt-down occurredart 2 (JP-A-53-138918) after about 3,000 30.7-33.5 cycles CDA 19400 No melt-down occurred3 (JP-A-58-163127) after 200,000 cycles 42.7-49.1 Al with Cu plating No melt-down occurred4 (1 μm) after 200,000 cycles 32.2-34.7Presentinvention Al with Cu plating No melt-down occurred5 (1 μm) + Sn plating after 200,000 cycles 30.5-32.5 (1 μm)__________________________________________________________________________ Remarks: Al used as the material is JISH4000 A1080.
TABLE 2__________________________________________________________________________Sample TemperatureNo. Sample Cyclic test rise (°C.)__________________________________________________________________________ Al with Cu plating No melt-down occured6 (3 μm) after 200,000 cycles 32.0-33.8 (Al: A1080)Present Al with Cu plating No melt-down occuredinvention7 (1 μm) after 200,000 cycles 32.8-33.5 (Al:A1200) Al with Cu plating No melt-down occured8 (1 μm) after 200,000 cycles 34.5-35.2 (Al:A2218)__________________________________________________________________________ Remarks: A1200 and A2218 are specified in JIS as materials suitable for forming plates, bars, sheets, strips, etc.
The fuse made of the material embodying the present invention shows a small temperature rise and has a high durability for the reasons which will be described below.
When the fuse is connected in a circuit where a relatively large current flows, local melting of the aluminum base starts first at about 660° C. due to heat generated as a result of conduction of the current. Although the current tends to flow more through the copper plating than the aluminum base of molten state, the melting point of copper is quickly reached because the thickness of the copper plating is 3 μm at the most. Since, at this time, the aluminum base is in its locally molten state already and is sharply severed at the molten area without the chance of forming its oxide film. Thus, although the fuse is locally heated up to a high temperature, the length of time elapsed until attainment of such a high temperature level is very short. Therefore, an adjacent part is not adversely affected by the heat generated from the fuse, and the safety of the adjacent part is ensured.
Also, the metal particles of the fuse of the present invention do not become excessively large unlike those of zinc, and the fuse has a long useful service life as will be apparent from Tables 1 and 2.
It will be understood from the foregoing description that a fuse made of the material according to the present invention generates a small quantity of heat and has a long useful service life when connected in a circuit where a relatively large current flows. Further, since the material costs of aluminum and copper, as well as that of tin, used for making the fuse are low, the fuse can be produced at a low cost.
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Disclosed is a fuse material consisting of aluminum or a rollable aluminum alloy having a copper plating deposited thereon and optionally being provided with a tin plating deposited on the copper plating. A fuse made of the fuse material shows a small temperature rise and has an extended useful service life as compared to conventional fuses.
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This is a continuation of co-pending application Ser. No. 08/925,230 filed Sep. 8, 1997, which issued as U.S. Pat. No. 6,147,194 on Nov. 14, 2000, which was a divisional of 07/232,302 filed Aug. 12, 1988, which issued as U.S. Pat. No. 5,665,583 on Sep. 19, 1997.
BACKGROUND OF THE INVENTION
The present invention relates generally to inosine 5′-monophosphate dehydrogenase (IMPDH) and more particularly to purified and isolated DNA sequences that encode proteins possessing the biological properties of eukaryotic IMPDH, to the expression products of these DNA sequences in transformed or transfected host cells, to recombinant and synthetic proteins and peptides having amino acid sequences based on the sequence of amino acids deduced from these DNA sequences, to antibodies specific for such proteins and peptides, to analytical procedures for the detection and quantification of such peptides and proteins and nucleic acids related thereto, to the use of IMPDH-encoding DNA sequences as selectable markers and as tools for gene amplification in recombinant hosts, and to cell lines and organisms displaying enhanced production of IMPDH and/or elevated levels of products such as guanosine monophosphate (GMP), whose synthesis in cells is dependent on the activity of IMPDH.
The enzyme IMPDH (EC 1.2.1.14) catalyzes the formation of xanthine monophosphate (XMP) from inosine monophosphate (IMP). In the purine de novo synthetic pathway, IMPDH is positioned at the branch point in the synthesis of adenine and guanine nucleotides and is thus the rate-limiting enzyme in the de novo synthesis of guanine nucleotides, such as guanosine 5-monophosphate. [Weber, Cancer Res ., 43:3466-3492 (1983); Weber, et al., Adv. Enzyme Regul ., 18:3-26 (1980)]. Inhibition of cellular IMPDH activity results in an abrupt cessation of DNA synthesis [Franklin, et al., Biochem. J ., 113:515-524 (1969); Cohen, et al., J. Biol. Chem ., 256:8713-8717 (1981); and Duan, et al., Cancer Res ., 47:4047-4051 (1987)] and a cell cycle block at the Gl-S interface [Cohen, et al., Cancer Res ., 43:1587-1591 (1983)]. Because IMPDH is essential in providing the necessary precursors for DNA and RNA biosynthesis, normal tissues that exhibit increased cell proliferation generally exhibit increased IMPDH activity [Jackson, et al., Nature , 256:331-333 (1975); Jackson, et al., Biochem. J ., 166:1-10 (1977), Cooney, et al., Anal. Biochem ., 130:339-345 (1983)]. Similarly, increased cell proliferation is accompanied by elevated enzyme activity in certain rat hepatomas with varied growth rates. Weber, Cancer Res ., 43:3466-3492 (1983). These hepatomas manifest IMPDH activities that are disproportionately higher than those of normal tissues, suggesting that IMPDH is associated with cell proliferation and may be linked to either malignant cell transformation or tumor progression.
To investigate the role of IMPDH in growth regulation and malignancy, attempts have been made to purify the enzyme to homogeneity to allow preparation of specific antibodies thereto and to isolate IMPDH-encoding DNA.
IMPDH isolated from bacterial sources has been determined to vary widely with respect to allosteric properties, size, and subunit composition. IMPDH isolated from E. coli has been purified and characterized as a tetramer of identical subunits [Gilbert, et al., Biochem. J ., 183:481-494 (1979); and Krishnaiah, Arch. Biochem. Biophys ., 170:567-575 (1975)]. Unlike mammalian cell enzymes, the E. coli IMPDH enzyme is reported to be insensitive to the inhibitory effect of mycophenolic acid [Franklin, et al., Biochem. J ., 113:515-524 (1969)]. In E. coli , IMPDH has been determined to be the product of the guaB locus and the sequence of the quaB structural gene and surrounding DNA has been determined to span 1.533 kb and to code for an IMPDH subunit sequence of 511 amino acids with a calculated molecular weight 54,512 [Tiedeman, et al., Nucleic Acids Research , 13:1303 (1985)].
Miyagawa, et al., Bio/Tech ., 4:225 (1986), have described the cloning of the Bacillus subtilis IMPDH gene, which, upon re-introduction into a B. subtilis strain that overproduced inosine, resulted in an increased production of guanosine, accompanied by a decreased accumulation of inosine. The IMPDH gene was localized on a 6.5 kb insert and further localized to a Hind III-partially digested 2.9 kb fragment. However, the gene was not reported to have been isolated and no information was provided with respect to the DNA sequence of the gene.
While a number of workers have reported the purification or partial purification of IMPDH from a variety of eukaryotic cell sources, including ascites cells, thymus cells, mouse LS cells, and other mammalian cells, none have been successful in obtaining substantial information about the amino acid sequence of the IMPDH protein, or in establishing the utility of anti-IMPDH antibodies in the characterization of the cellular role of IMPDH.
Eukaryotic IMPDH has been obtained from one plant and several animal species, including cowpea nodule cells [Atkins, et al., Arch. Biochem. Biophys ., 236:807-814 (1985)], Yoshida sarcoma ascites cells [Okada, et al., J. Biochem ., 94:1605-1613 (1983)], rat hepatoma 3924A cells [Ikegami, et al., Life Sci ., 40:2277-2282 (1987) and Yamada, et al., Biochem ., 27:2193-2196 (1988)] and Chinese hamster cells [Collart, et al., Mol. Cell. Biol ., 7:3328-3331 (1987)]. The disclosures of the last-mentioned publication by the present inventors are specifically incorporated by reference herein. In all of these reports, denaturing polyacrylamide gel electrophoresis was used to assess purity and to estimate molecular weight. The reported molecular weight for all of the above mentioned enzymes was approximately 56,000. A polyclonal antibody raised against the purified protein was prepared for the enzyme isolated from Yoshida sarcoma ascites cells, rat hepatoma 3924A cells, and Chinese hamster cells. As described in detail, infra, only in the case of the antibody prepared against the Chinese hamster enzyme was an antibody determined to be useful in examination of cellular regulation and useful in isolation of eukaryotic IMPDH-encoding DNA.
There continues to exist a need in the art for information regarding IMPDH enzymes of eukaryotic origins (especially of vertebrate and more particularly of mammalian origins) such as can be provided by the isolation, sequencing, and recombinant system utilization of DNA sequences encoding the same. The availability of such materials and information would make possible a vast array of novel systems and methodologies based thereon including methods and materials useful in production of products displaying IMPDH activity.
BRIEF SUMMARY OF THE INVENTION
The present invention provides novel purified and isolated DNA sequences encoding eukaryotic inosine 5′-monophosphate dehydrogenase (IMPDH), which have allowed for the initial determination of the primary structural conformation (i.e., amino acid sequence) of the eukaryotic protein. Specifically provided are sequences encoding human, mouse, and Chinese hamster IMPDH. Provided also are alternate DNA forms such as genomic DNA and DNA manufactured by partial or total chemical synthesis from nucleotides. The association of DNA sequences of the invention with expression regulatory DNA sequences, such as promoters, enhancers and the like, allows for in vivo and in vitro transcription to form messenger RNA, which, in turn, is subject to translation to provide IMPDH protein in large quantities.
Among the multiple aspects of the present invention, therefore, is the provision of (a) novel eukaryotic IMPDH DNA sequences as set out in FIG. 1A, FIG. 1B, FIG. 1C, FIG. 1D, FIG. 2A, FIG. 2B, FIG. 2C, FIG. 2D, FIG. 3A, FIG. 3B, and FIG. 3C; (b) IMPDH-encoding DNA sequences, which hybridize thereto under hybridization conditions of the stringency equal to or greater than the conditions described herein as used in the initial isolation of cDNAs of the invention, which also encode proteins with IMPDH biological activities; and (c) DNA sequences encoding the same, allelic variant and/or analog IMPDH proteins, which incorporate, at least in part, degenerate codons. Correspondingly provided are viral or circular plasmid DNA vectors incorporating such DNA sequences and prokaryotic and eukaryotic host cells transformed or transfected with such DNA sequences and vectors, as well as novel methods for the recombinant production of IMPDH proteins through cultured growth of such hosts and isolation thereof from the hosts or from their culture media.
According to another of its aspects, cell lines and organisms having enhanced production of IMPDH, as well as enhanced production of guanosine monophosphate (GMP), are also provided. Preferred embodiments of such cells include the transformed or transfected host cells described initially above. Also comprehended are naturally occurring or mutagenized eukaryotic cells, which are selected for increased IMPDH production (e.g., on the basis of capacity for growth in the presence of elevated levels of cytotoxic IMPDH inhibitors) and then additionally subjected to stepwise incremental selection in the presence of a cytotoxic IMPDH inhibitor such as mycophenolic acid (MPA), ribavirin, brenidin, and tiazofurin. Illustratively, naturally occurring or mutagenized cells capable of growing in medium containing 0.1 to 0.5 μg/mL MPA are subjected to stepwise selection at increasingly higher levels of the agent.
The preparation and incorporation of IMPDH DNA sequences for use as a selectable marker to select for cells that have incorporated a selected fragment of foreign DNA into their genetic material is also embraced by the present invention. In one illustration of the DNA selection systems of the invention, Chinese hamster IMPDH encoding DNA is operatively associated in a plasmid construct with appropriate expression control sequences, and e.g., a DNA sequence coding for the E. coli gpt protein. This plasmid construct is then introduced into hamster cells, and cells functionally incorporating the IMPDH/gpt gene construct are selected on the basis of survival in culture media that contains MPA.
Novel protein products of the invention include recombinant-produced compounds having the primary structural conformation (i.e., amino acid sequence) of IMPDH protein, as well as peptide fragments thereof and synthetic peptides assembled to be duplicative of amino acid sequences thereof. Proteins, protein fragments, and synthetic peptides of the invention are projected to have numerous uses including therapeutic, diagnostic and prognostic uses and also provide the basis for the preparation of monoclonal and polyclonal antibodies specifically immunoreactive with IMPDH. Preferred protein fragments and synthetic peptides include those that duplicate continuous antigenic epitope sequences of the full-length protein.
Preferred protein products of the invention include approximately 56 kDa IMPDH peptides having the deduced sequence of 514 amino acid residues for human and Chinese hamster proteins set out in FIG. 1A, FIG. 1B, FIG. 1C, FIG. 1D, FIG. 2A, FIG. 2B, FIG. 2C, and FIG. 2 D.
The preferred 56 kDa IMPDH polypeptide is characterized by a capacity to specifically bind IMP with a K i equal to approximately 25 μmol, a sensitivity to inhibition by IMPDH inhibitors such as mycophenolic acid, and immunoprecipitability by rabbit anti-IMPDH antisera.
Antibodies specific for the novel peptide products of the invention preferably bind with high immunospecificity to IMPDH protein, fragments, and peptides, recognizing eptitopes that are not common to other proteins.
Also provided by the present invention are novel procedures for the detection and/or quantification of the IMPDH protein, as well as the corresponding nucleic acids, e.g., DNA and mRNA, associated therewith. Antibodies of the invention may be used in known immunological procedures for quantitative detection of IMPDH protein in fluid and tissue samples. DNA sequences of the invention may be suitably labeled and used for the quantitative detection of mRNA encoding IMPDH or assessment of any genetic alteration resulting in amplification or rearrangement of the IMPDH gene.
Other aspects and advantages of the present invention will be apparent upon consideration of the following detailed description thereof, which includes illustrative examples of the practice of the invention, reference being made to the drawing wherein:
FIG. 1A, FIG. 1B, FIG. 1C, FIG. 1D set forth the base sequence of a human species IMPDH cDNA (SEQ ID NO:1), and the deduced amino acid SEQUENCE ID NO. 7 of the protein product of expression of the sequence;
FIG. 2A, FIG. 2B, FIG. 2C, and FIG. 2D set forth the base sequence of a Chinese hamster species IMPDH cDNA (SEQ ID NO:2) and the deduced amino acid sequence (SEQ ID NO:8) of the expression product thereof;
FIG. 3A, FIG. 3B, and FIG. 3C set forth the base sequence for 737 bases of the 750 bases of a mouse species cDNA (SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5, and SEQ ID NO:6) fragments; and
FIGS. 4A and 4B provide a comparison of the human (SEQ ID NO:7) and Chinese hamster species IMPDH deduced amino acid sequences (SEQ ID NO:8).
DETAILED DESCRIPTION
The following examples operate to illustrate practice of the invention in its numerous aspects. More particularly, Example 1 relates to the to the generation of cultured cell variants displaying altered levels of IMPDH activity as a result of mutagenesis and incremental selection. Example 2 relates to IMPDH purification from Chinese hamster cells and the partial purification of IMPDH from human cells. Example 3 relates to the preparation of rabbit anti-IMPDH antiserum, the isolation of IMPDH-specific IgG, and the use of this IgG in immunoblot analysis. Example 4 relates to the isolation and characterization of IMPDH cDNA from a mouse bone marrow library, a Chinese hamster library, and a human cDNA library. Example 5 relates to the protease digestion and amino terminal sequencing of the purified Chinese hamster IMPDH protein. Example 6 relates to the use of an IMPDH DNA construct as a selectable marker. Example 7 relates to the analysis of IMPDH expression in normal and in malignant cells.
The examples that follow are for illustrative purposes only and are not intended in any way to limit the scope of the invention.
EXAMPLE 1
Generation of Cell Variants with Altered IMPDH Activity
To investigate the control of IMPDH enzyme in mammalian cells, cell variants were generated from the Chinese hamster V79 line of cells according to the general procedures of Huberman, et al., Proc. Nat'l. Acad. Sci . ( USA ), 78:3151-54 (1981).
To generate MPA-resistant cells, 4×10 6 2-day-old exponentially growing V79 cells cultured in 100-mm Petri dishes were treated with the chemical mutagen/carcinogen N-methyl-N′-nitro-N-nitrosoguanidine (MNNG). After 3 hours of treatment, both the control and the MNNG-treated cells were dissociated with trypsin ethylenediaminetetraacetic acid (EDTA) solution and seeded at 10 5 cells per 100-mm Petri dish. Unless otherwise noted, the cells were dissociated 6 days later and reseeded at 200 cells per 60-mm dish in 5 mL of medium for the determination of cloning efficiency and at 2×10 4 cells per 60-mm dish in 4 mL of medium for the determination of the number of MPA-resistant cells. Two days later, MPA was added in 1 mL of medium to give a final concentration of 1 μg/mL. Thus, an expression time of 8 days was used for the selection of MPA resistance. Cloning efficiency was determined by counting the number of Giemsa-stained colonies of six to eight dishes per point at 7-8 days after cell seeding; the number of MPA-resistant cell variants was determined by counting Giemsa-stained colonies in 40 Petri dishes per point at 18-21 days after cell seeding. The frequency of the drug-resistant colonies was calculated per 10 5 colony-forming cells based on the cloning efficiency and the number of cells seeded for mutant selection.
In addition, after a 6-day expression time, a sample of control and MNNG-treated (0.5 μg/mL) cells was incubated with MPA at 0, 0.1, and 0.3 μg/mL. Both the control and MNNG-treated cells had a similar growth rate, yielding, after 5 days of growth, means (±SD) of 5.0±0.3, 1.4±0.2, and 0.2±0.05×10 6 cells per Petri dish for MPA at 0, 0.1, and 0.3 μg/mL, respectively. These results indicate that control and MNNG-treated cells exhibit not only a similar growth rate but also a similar susceptibility to the cytotoxic effect of MPA.
According to the present invention, the resistance level of one of these cell variants was further increased by a stepwise selection in the presence of increasing concentrations of MPA. After adaptation to the higher concentration of MPA, the cells were seeded in medium containing an increased concentration of MPA at 200 cells per 60-mm petri dish, and MPA-resistant colonies were isolated 8 days later.
Four replications of this procedure resulted in four variants, designated VM1 through VM4, which exhibited resistance to 5, 10, 25, and 50 μg/mL MPA, respectively, whereas the parental V79 cells were resistant to only 0.1 μg/mL MPA. The increased resistance to MPA cytotoxicity in the variant cells was associated with an increased activity of IMPDH in cell homogenates, with VM1 cells exhibiting about a six-fold increase in IMPDH activity over the parental cells, and VM2, VM3, and VM4 cells expressing about 7-, 9-, and 11-fold increases in IMPDH activity, respectively.
EXAMPLE 2
IMPDH Purification from Chinese Hamster Cells and Human Cells
The generation of the IMPDH overproducing VM2 cell variant in Example 1 facilitated the isolation of a highly purified preparation of IMPDH allowing for the development of a specific anti-IMPDH antibody for subsequent cDNA cloning and immunoblot analysis.
IMPDH was isolated from VM2 Chinese hamster cells as follows. VM2 cells were scraped from the tissue culture plates, and washed with a phosphate buffer saline solution (PBS, pH 7.4, containing 137 mM NaCl, 2.6 mM g/L KCl, 1.5 mM KH 2 PO 4 , and 8 mM Na 2 HPO 4 ) containing 0.5 mM phenylmethylsulfonyl fluoride (PMSF). The cells were collected by centrifugation at 800×g for 5 minutes and the pellet homogenized in 10 volumes of buffer A, pH 7.2, which contained 20 mM KH 2 PO 4 , 50 mM KCl, 0.5 mM dithiotreitol (DTT) and 0.1 mM PMSF. The cell homogenate was centrifuged at 180,000×g for 40 minutes at 4° C. The supernatant was removed and applied to a hydroxylapatite column (2.5×30 cm) equilibrated with buffer A. The column was then washed with 10 volumes of buffer A and the protein eluted with a linear gradient of 0-17.5% (NH 4 ) 2 SO 4 (400 mL) in buffer A.
IMPDH activity was determined by measuring the IMP-dependent NAD reduction at 37° C. by monitoring the change in absorbance at 340 nm. One unit of enzyme activity was defined as the amount of enzyme forming 1 μmole of NADH per minute at 37° C. under the prescribed assay conditions. Those fractions having enzyme activity were combined and the solution adjusted to 50% saturation with (NH 4 ) 2 SO 4 . After incubation of this solution at 4° C. for one hour, the precipitate was collected by centrifugation at 12,000×q for 10 minutes. The pellet was dissolved in 50 volumes of buffer B (20 mM Tris-HCl, pH 7.0, 10% glycerol, and 0.5 mM EDTA) and the solution applied to a Blue-Sepharose™ CL-6B column (1.5×20 cm) equilibrated with buffer B. The column was washed with 10 volumes of buffer B followed by 2 volumes of buffer B containing 10 mM NAD and 1 mM IMP. The enzyme was eluted with a linear gradient of 0-1M KCl in 200 mL of buffer B. Fractions with a high specific activity were combined, concentrated by ultrafiltration, and dialyzed against J buffer B. The dialyzed material was applied to a DEAE Sepharose™ column (1×5 cm) equilibrated with buffer B. The column was washed with buffer B and the enzyme eluted with a linear KCl gradient (0-0.5 M) in 50 mL of buffer B. Protein concentration was determined by the BCA assay method (Pierce Chemical Co., Rockford, Ill.) with bovine serum albumin used as the standard. The enzyme was purified from a microsomal supernatant to a final specific activity of 1080 mU/mg of protein in a 23% yield.
Polyacrylamide gel electrophoresis was carried out in 7.5% gels as described in Laemmli, Nature , 227:680-685 (1970). Upon sodium dodecyl sulfate (SDS) gel electrophoresis, the purified protein migrated as a single species with an apparent molecular weight of 56,000. Two proteins of identical molecular weight were detected by two-dimensional (2D) gel electrophoresis. One of these proteins, constituting less than 10% of the total amount of the protein, is presumably a charge-modified form of the major species. No other proteins were detected when up to one microgram of the purified protein was analyzed by electrophoresis.
Kinetic studies were carried out by varying the substrate conditions. In all cases, linear reciprocal plots were defined by simple regression analysis of the data. The kinetic characteristics of the purified Chinese hamster protein were indistinguishable from those reported for the partially purified enzyme from V79 cells. The K m values of the Chinese hamster enzyme for IMP and NAD were calculated to be 21 and 29 μM, respectively. Moreover, the Chinese hamster enzyme retained a high sensitivity to MPA with a K i in the nanomolar range.
IMPDH was partially purified from human HL-60 cells obtained from R. C. Gallo, National Cancer Institute, Bethesda, Md., and were processed as described above with respect to Chinese hamster cells. Comparison of purified Chinese hamster protein with the partially purified human enzyme by 2D-gel electrophoresis indicates these proteins are of a similar molecular weight but that the human enzyme is slightly more acidic than the Chinese hamster enzyme. This observation was later confirmed by a comparison of the deduced amino acid sequences from the human and Chinese hamster cDNA clones (discussed infra), which indicated the human enzyme has one fewer positively charged and one additional negatively charged amino acid.
EXAMPLE 3
Preparation of Rabbit Anti-IMPDH Antiserum, Isolation of IMPDH Specific IgG, and and Development of Assay System
An anti-IMPDH antiserum was prepared in rabbits by multiple-site injections of an emulsion of the purified Chinese hamster enzyme, prepared according to Example 2, and Freund's Complete Adjuvant [Vaitukaitis, Methods Enzymol ., 73:46-52 (1981)]. IMPDH specific IgG was isolated from the immune serum by Protein A Sepharose™ (Pharmacia Inc., Piscataway, N.J.) chromatography. By immunoblot analysis, this antibody was shown to react with IMPDH isolated from Chinese hamster, rat and human cells.
Assay systems were devised for determination of cellular IMPDH based on use of the rabbit antibody. According to these systems, target cells were washed in PBS and the cell pellet resuspended in 1-5 mL of 20 mM Tris-HCl, pH 6.8, 200 mM KCl, 1 mM DTT (buffer A). The cells were then centrifuged at 12,000×g for 8 seconds and the pellet resuspended in 1.2 mL of buffer A. After three freeze/thaw cycles to disrupt the cells, the suspension was centrifuged at 12,000×g for 10 minutes. The supernatant was removed and 3M NaAc, pH 5.2, was added to give a final concentration of 180 mM. After incubation on ice for 30 minutes, the protein precipitate was recovered by centrifugation for 10 min. in a microfuge. The IMPDH-enriched pellet was resuspended in 0.3 mL of 20 mM Tris-HCl, pH 8.3, 50 mM NaCl, 1 mM DTT. After removal of any insoluble material by centrifugation, aliquots were removed for the determination of enzyme activity and protein content and the remainder of the sample was stored at −20° C.
Western blot analyses [Towbin, et al., Proc. Nat'l. Acad. Sci. USA , 76:4350-4354 (1979)] were carried out with the IMPDH-specific IgG prepared from the anti-IMPDH anti-serum by Protein A affinity chromatography. The detection level is approximately 1×10 −6 units of IMPDH, where one unit of enzyme is defined as the amount forming 1 μmol of product per minute at 37° C. under standard assay conditions. The sample is diluted with 5x gel sample buffer (6% SDS; 200 mM DTT; 300 mM Tris-HCl, pH 6.8; 0.25% bromophenol blue; 30% glycerol) and electrophoresed at 50 volts for 12-18 hours. The proteins are transferred to nitrocellulose (Scheicher and Schuell, BA83, 0.2 μm) in 50 mM Tris-HCl, 40 mM glycine, pH 8.3, 15% methanol by application of 100 mamps (20 V) for 8-12 hours. The nitrocellulose blot is incubated in TS (25 mM Tris-HCl, pH 7.5; 150 mM NaCl) with 5% nonfat dry milk for 30 minutes and then with the anti-IMPDH antibody overnight. Immune complexes were visualized by incubation with goat anti-rabbit IgG followed by incubation with rabbit IgG conjugated with horseradish peroxidase and 4-chloronapthol (3 mg/mL in 20% methanol with 0.01% H 2 O 2 ), used as the substrate. [Kittler, et al., Anal. Biochem ., 137:210-216 (1984)].
EXAMPLE 4
Isolation and Characterization of IMPDH cDNA from Mouse Bone Marrow, Chinese Hamster, and Human cDNA Libraries
The rabbit antiserum prepared according to Example 3 from the purified Chinese hamster protein was used to screen a λgt11 cDNA expression library derived from mouse bone marrow [Clonetech Laboratories, Inc. (Palo Alto, Calif.)], by means of the screening procedure outlined by Huynh, et al., DNA Cloning (Glover, D. M., ed.) 1:73-75 (1985) IRL Press Limited, Washington, D.C. The nitrocellulose filters containing the absorbed phage proteins were incubated in TS (25 mM Tris-HCl, pH 7.5; 150 mM NaCl) with 5% nonfat dry milk for 30 minutes and then with the anti-IMPDH antibody overnight. Immune complexes were visualized as described in Example 3, supra.
A phage with a 750 bp cDNA insert was isolated from this library and the insert subsequently subcloned into a pUC8 vector designated pUC8/IMPDH5. Confirmation of this cDNA probe as having IMPDH coding sequences was obtained by translational arrest as described in Collart, et al., Mol. Cell. Biol ., 7:3328-3331 (1987). This technique indicates the extent to which the hybridization of a cDNA probe with putatively homologous mRNA can specifically reduce the yield of the translation product. Poly(A) + RNA isolated from the VM2 cells was used as a source for IMPDH mRNA. The pUC8/IMPDH5 probe effectively blocked the translation of an immunoprecipitable IMPDH product in a dose-dependent manner, thus validating the identity of the clone as a cDNA probe for IMPDH.
A Chinese hamster cDNA library (a generous gift from Victor Ling, University of Toronto, Toronto, Canada) was prepared from a CHO cell line E29Pro+ (Elliott, et al., Mol. Cell. Biol ., 5:236-241 (1985); library construction was with the pCD vector system in E. coli x1776 [Okayama, et al., Mol. Cell. Biol ., 2:161-170 (1982); Okayama, et al., Mol. Cell. Biol ., 3:280-289 (1983)]. A human peripheral blood leukocyte cDNA library was purchased from Clonetech Laboratories, Inc. (Palo Alto, Calif.). Both libraries were screened with the mouse IMPDH cDNA probe by using the procedure outlined by Maniatis, et al., “Molecular Cloning”, Ch. 10, pages. 315-317 and 320-321; Fritsch, F. T., and Sambrook, J., eds.; (Cold Spring Harbor, N.Y. 1982).
The nitrocellulose membranes containing the recombinant DNA were prehybridized for 2 hours at 65° C. in a phosphate buffer, pH 7.2, containing 0.5 M Na 2 PO 4 , 1 M NaCl, 1 mM EDTA, 0.5% SDS and 100 μg/mL denatured sonicated salmon sperm DNA. The prehybridization solution was replaced with hybridization solution (prehybridization solution minus the DNA) containing 1×10 6 cpm/mL of 32 P-labeled mouse probe, prepared as described by Feinberg, A. P., et al., Anal. Biochem ., 132:6-13 (1983), and the membranes incubated at 65° C. for 36 hours. The membranes were washed 3 times for 30 min. in 10 mM NaH 2 PO 4 , pH 7.4, 1 mM EDTA, 180 mM NaCl at 50° C. The membranes were dried, sealed in plastic wrap and exposed to x-ray film (Fuji RX) with an intensifying screen (Dupont Cronex “Lightning Plus”) at −70° C.
Positive plaques were purified and the phage DNA isolated. Inserts of recombinant IMPDH clones were excised from the positive clones with Eco R1 restriction enzyme and isolated by an electro-elution technique as described by Zassenhaus, et al., Anal. Biochem ., 125:125-130 (1982). Insert homogeneity was verified by gel electrophoresis and the concentration determined by measuring the absorbance at 260 nm.
The cloned mouse, human and Chinese hamster IMPDH DNAs were inserted into an M13 vector [Messing, J., Methods Enzymol ., 101:20-78 (1983)] and were sequenced according to the dideoxy method [Sanger, F., et al., Proc. Nat'l. Acad. Sci. USA , 74:5463-5467 (1977)]. Each nucleotide sequence was read an average of four times and a minimum of once in each direction. Sequence data were compiled and analyzed by the use of the DNASTAR (Madison, Wis.) system digitizer and software and the accompanying protocols.
As illustrated in FIG. 1A, FIG. 1B, FIG. 1 C and FIG. 1D, the largest human cDNA clone, designated HIMP, has 1642 base pairs and contains an open reading frame corresponding to a protein of 514 amino acids with a calculated molecular weight of 56,282. A consensus poly(A) addition site (AATAAA) is located approximately 30 nucleotides from the termination codon at nucleotides 1584-1586. The sequence preceeding the ATG methionine initiation codon at position 48 is consistent with the eukaryotic initiation site consensus sequence described by Kozak, Nucleic Acids Res ., 12:857-872 (1984). Plasmid HIMP, containing the cloned human DNA sequence as an EcoRI insert ligated into the EcoRI site of a Bluescript KS+ vector (Stratagene, LaJolla, Calif.) and transformed into E. coli DH-1 cells was deposited on Jul. 29, 1988 with the American Type Culture Collection, Rockville, Md. under A.T.C.C. accession No., 67753.
As illustrated in FIG. 2A, FIG. 2B, FIG. 2 C and FIG. 2D, the organization of the Chinese hamster cDNA is similar to that of the human clone and specifies a protein identical in size to the human protein, and contains the poly(A) and ATG concensus sequences.
The mouse DNA fragment was sequenced from both the 51-end (FIG. 3A) and the 3′-end (FIG. 3 B and FIG. 3 C). These sequences comprise 737 of the 750 nucleotide base pairs comprising the mouse cDNA. The mouse cDNA sequence(s) display a high degree of similarity to the human cDNA sequence and correspond(s) to the region spanned by nucleotides 405-1157 of the human HIMP clone.
FIG. 4 A and FIG. 4B provides a comparison of the deduced amino acid sequences of the human and Chinese hamster proteins and indicates a high level of conservation of the amino acid sequence information. The non-matching amino acids are surrounded by a box with those having similar chemical properties denoted by an asterisk. Of the 514 amino acids specified by the two open reading frames, only eight amino acid differences are noted between the human and the Chinese hamster proteins. Futhermore, five out of eight of these amino acid changes are conservative with respect to the chemical nature of the amino acid. This similarity in amino acid sequence is mirrored in the DNA sequences that show an 89% identity.
Similar results are also obtained from a comparison of the sequence information derived from the mouse IMPDH cDNA, set forth in FIG. 3A, FIG. 3 B and FIG. 3C, and that derived from the human cDNA set forth in FIG. 1A, FIG. 1B, FIG. 1C, and FIG. 1D, wherein a 89% identity was observed. These results confirm the identity of the human, Chinese hamster, and mouse clones as those for IMPDH and demonstrate the high conservation of the amino acid sequence of the enzyme among these three species. In contrast, a comparison was made between the deduced amino acid sequence of the cloned human IMPDH cDNA with all sequences in the NBRF database by using the software provided by the University of Wisconsin Genetics Computer Group [Devereux, et al., Nuc. Acids. Res ., 12:387-395 (1984)]. A degree of homology (score 347, 57% similarity over a stretch of 506 amino acids) was observed for the bacterial IMPDH protein. Three regions of 50 amino acids in the interior of the protein sequence show a 56-67% identity in amino acid sequence. If allowance is made for amino acids of similar chemical nature, the similarity of these three regions is approximately 78%.
The similarity of the human, mouse, and Chinese hamster proteins indicates a functional selection for conservation of amino acid sequence. The dissimilarities between eukaryotic and prokaryotic amino acid sequences are indicative of a substantial lack of homology of DNA sequence.
EXAMPLE 5
Protease Digestion and Amino Terminal Sequencing of Purified Chinese Hamster IMPDH Protein
Initial attempts to sequence the purified Chinese hamster IMPDH protein indicated that the amino terminus was blocked. In an attempt to further verify the identity of clones putatively coding for the IMPDH protein obtained in Example 4, a portion of the Chinese hamster protein purified according to Example 2 was subjected to protease digestion and amino acid sequencing as follows.
A sample of the purified Chinese hamster protein in 20 mM Tris-HCl, pH 8.0, 200 mM KCl, 10 mM DTT, and 0.25% SDS was heated at 65° C. for 2 minutes. Staphlococcus aureus V-8 protease was added at a weight/weight ratio of protease to substrate of 1:100, and the solution was incubated at 37° C. for two hours. The sample was then chilled to 0° C. and centrifuged at 12,000×g for two minutes. The resulting peptides in the supernatant were purified by reversed-phase high-pressure liquid chromatography on a Synchropack C4 column (4.1×100 mm). Small aliquots (50 μL) containing approximately 350 pmoles of digested enzyme were loaded to minimize the effects of SDS. The peptides were eluted with a linear gradient (0-100%) of 60/39/1:acetonitrile/water/trifluoreacetic acid. Flow rate was 1 mL/min with a gradient duration of 30 minutes. Peptide peaks were collected in microfuge tubes, lyophilized, and stored at −70° C. Amino terminal sequencing was performed at the Chicago Medical School, North Chicago, Ill., by using an Applied Biosystems (Foster City, Calif.) protein sequencer, amino acid analyzer, and the accompanying protocols.
A sequence of 35 amino acids obtained by analysis of one of the peptides was compared with the protein sequence deduced from the human and Chinese hamster cDNA clones. This 35 amino acid segment, indicated by a box in FIG. 1C, corresponds to deduced amino acid residues 336-370 in both the human and Chinese hamster proteins.
EXAMPLE 6
The Preparation and Use of an IMPDH DNA Construct as a Selectable Marker
This example describes the preparation and use of IMPDH DNA constructs, which permit identification of cells that have incorporated a selective fragment of foreign DNA into their genetic material. The successful practice of the procedures is based on the requirement of IMPDH as a normal constituent of the cell for cell survival and the knowledge that inhibitors of IMPDH can be cytotoxic to cells at concentrations of 0.1 to 0.5 μg/mL. Increased cellular levels of IMPDH confer resistance to IMPDH inhibitors and negate the cytotoxic effects of these agents.
DNA sequences that can be readily combined with the IMPDH DNA sequence include any DNA desired sequences that can be ligated into the plasmid construct and that will not compromise the ability of the IMPDH cDNA product to specify resistance to MPA (myophenolic acid) or to other IMPDH inhibitors. The constructs can be incorporated into cells by using standard DNA transfection technology (Davis, et al., Molecular Biology , 18-1:286-289; Davis, L. G., et al., eds. Science Publishing Co., Inc.; Elsevier, N.Y. 1986). After transfection, the addition of an IMPDH inhibitor to the culture medium will permit the growth of only those cells that have incorporated the construct into their genetic material. Cells that have not acquired the construct will be killed by the IMPDH inhibitor.
DNA sequences coding for the IMPDH enzyme were ligated into the pMSG plasmid (Pharmacia, Inc., Piscataway, N.J.), which contains appropriate expression sequences and the DNA sequence coding for the E. coli gpt protein. A SMAI-EcoRV fragment derived from the HIMP plasmid was subcloned into the SMAI site of the pMSG plasmid. This process placed the IMPDH cDNA under the control of a dexametasone-inducible mouse mammary tumor virus promoter. This plasmid construct was then introduced into V15 hamster cells (derived by mutagen treatment of Chinese hamster V79 cells and having no detectable HGPRT activity) by using the calcium phosphate DNA transfection technique described in Davis, et al., Molecular Biology , 18-1:286-289 (1986), supra.
After introduction of the construct into the hamster cells, mycophenolic acid (2 μg/mL) was added to the culture medium to select for those cells that had integrated the construct into their genetic material. Those cells that have integrated the construct into their genetic material produce the IMPDH enzyme and are therefore resistant to the cytotoxic effects of mycophenolic acid. A cell clone designated IMP1 was isolated; this clone was resistant to mycophenolic acid, indicating that the cells had incorporated the construct and were over-producing the IMPDH enzyme.
To verify that the resistance resulted from the incorporation of the construct, the MPA-resistant cells were successfully transferred to HAT medium. [Dulbecco's modified MEM containing 5% fetal bovine serum, aminopterin (2 μg/mL), and mycophenolic acid (25 μg/mL), and supplemented with hypoxanthine (15 μg/mL), thymidine (10 μg/mL), and xanthine (250 μg/mL)]. The ability of the cells to grow in the selective medium is attributable to the production of the E. coli gpt enzyme, which catalyzes the production of xanthine monophosphate from the reaction of xanthine and phosphoribosyl pyroposphate. Presence of the enzyme compensates for the purine de novo synthetic block imposed by the presence of aminopterin and MPA. The dual resistance to mycophenolic acid and HAT selection displayed by the transformed host is evidence that the resistance is attributable to the incorporation of DNA of the plasmid construct. Growth of the cells for several generations in the absence of mycophenolic acid did not decrease the resistance of the cell clone to MPA, indicating that the construct DNA was incorporated into host chromosomal material.
The IMPDH expression in the IMP1 cell clone and the V15 parent was examined to further define the basis for the mycophenolic acid resistance. A five-fold increase in the IMPDH activity in cell homogenates was observed in the IMP1 cells relative to the V15 parent. The cellular protein in these cell homogenates was electrophoresed through polyacrylamide gels, transferred to nitrocellulose and the amount of IMPDH enzyme was quantitated by immunoblot analysis with the anti-IMPDH antiserum prepared according to Example 3. In both the V15 and IMP1 cells, the antiserum reacted with a protein of 56 kDa corresponding to IMPDH. The amount of IMPDH enzyme was approximately five-fold higher in the IMP1 cells than in the V15 parent. Furthermore, the relative gel migration distance of the two proteins was identical, suggesting the IMPDH protein produced in the IMP1 cells has the same molecular weight as the V15 enzyme.
The amount of IMPDH mRNA in the parent and transformed cell lines was quantitated by Northern blot analysis by using a human IMPDH cDNA probe, prepared according to Example 4. Total cellular RNA was isolated by disrupting cells in guanidinium lysis buffer, pH 7.0, composed of 4 M guanidinium thiocyanate, 50 mM potassium acetate, 0.1 M β-mercaptoethanol, and 0.5% sarcosyl. The RNA was purified by centrifugation through a CsCl cushion as described by Chrigwin, et al., Biochemistry , 18:5294-5299 (1979). Hybridization signals corresponding to a 2.2 kilobase message were detected in both the IMP1 and V15 cells. However, the IMP1 cells contained an additional hybridization band corresponding to a message size of approximately 2.0 kilobases. This is the approximate message size expected for transcription of IMPDH mRNA from the plasmid construct. These results show that the IMP1 cells overproduce an IMPDH enzyme that is indistinguishable, by polyacrylamide gel electrophoresis, from that produced by V15 cells, and suggest that the increased IMPDH is a result of transcription from the plasmid construct containing the human IMPDH cDNA.
The foregoing example demonstrates that the selectable marker system of the invention provides a convenient means to study and obtain a regulated expression of virtually any selected foreign DNA. Moreover IMPDH is a dominant marker and no requirement for use of deficient hosts exists.
EXAMPLE 7
Analysis of IMPDH Expression in Normal and Malignant Cells
To determine whether increased amounts of IMPDH mRNA are the cause of the elevated levels of IMPDH in tumor cells, total cellular RNA from a variety of growing human leukemic cell lines and in normal peripheral blood granulocytes and lymphocytes was examined by Northern blot analysis through the use of the human cDNA as described in Example 6.
The human promyelocytic HL-60 leukemia cells were supplied by R. Gallo (National Cancer Institute, Bethesda, Md.). Cells were grown in Dulbecco's modified Eagle's medium or RPMI 1640 medium supplemented with 10% fetal calf serum, penicillin (100 U/mL), streptomycin (100 μg/mL), fungizone (0.25 μg/mL), and glutamine (2 mM) in a humidified incubator supplied with a constant amount of 8% CO 2 in air. Peripheral blood leukocytes were isolated from freshly drawn peripheral blood by Histoplaque-1077 (Sigma Chemical Co., St. Louis, Mo.) gradient centrifugation as described in Boyum, A., Scand. J. Clin. Lab. Invest ., 21(97):51-55 (1968); and Klock, J. C., and Bainton, D. F., Blood , 48:149-161 (1976). The mononuclear fraction contained predominately lymphocytes (85-95%), with monocytes comprising the remaining percentage. Immediately after purification, the lymphocytes were resuspended in appropriate buffers for either Western blot analysis or for isolation of total cellular RNA.
A reduced level of IMPDH expression was consistently observed for the RNA isolated from lymphocytes relative to the leukemic cell lines that had markedly increased expression of a 2.2 kb transcript corresponding to the IMPDH message. A similar pattern was observed for the amounts of cellular IMPDH detected with the specific IMPDH antibody in conjunction with the Western blotting technique. These results were similar in that much higher amounts of the IMPDH protein were observed in the leukemic cells relative to the peripheral blood cells. Similar results were also obtained for measurements of the enzyme activity in these cell lines. These marked differences in the expression, amount, and activity, between the normal and leukemic cells may be associated with the absence of cell replication in the normal cells and the active proliferation of the leukemic cells.
Cultured normal human fibroblast and sarcoma cells were similarly analyzed. The differences in IMPDH expression between the normal and tumor cells were not as great as those observed between the leukemic cells and the normal peripheral blood cells. However, all of the sarcoma cells had higher levels of mRNA expression, larger amounts of the protein, and greater IMPDH activity than the normal fibroblasts. These differences may again be attributable in part to a difference in the growth rate of the various cell types because the 37-h doubling time of the normal fibroblasts is greater than that observed for the sarcoma cells. However, other factors appear to influence the IMPDH expression because an absolute correlation between IMPDH activity and cellular growth rate was not always observed for the tumor cell lines.
The foregoing illustrative examples relate, in part, to the isolation of cDNA sequences encoding mouse, Chinese hamster, and human species IMPDH proteins. Those skilled in the art will readily appreciate that the DNA and deduced amino acid sequence information provided herein make available numerous other forms of DNA sequences, such as genomic sequences obtainable by hybridization screening of genomic libraries through the use of DNA probes designed by using the sequence information of FIG. 1A, FIG. 1B, FIG. 1C, FIG. 1D, FIG. 2A, FIG. 2B, FIG. 2C, FIG 2 D, FIG. 3A, FIG 3 B, and FIG. 3C, FIGS. 1-3, or manufactured DNA sequences synthesized from nucleic acids and potentially including alternate (degenerate) codons specifying the same amino acids, or DNA sequences comprising, e.g., part cDNA and part manufactured DNA. In a like manner, the DNA sequence information provided herein enables the isolation of other eukaryotic DNAs encoding IMPDH such as avian (chicken, turkey), fish, and mammalian (bovine, ovine, porcine) species DNAs by means of hybridization screening under appropriate stringency conditions.
The availability of the above-noted DNA sequences allows for preparation of IMPDH by in vitro transcription and translation of the DNA and for the development of a wide variety of viral or circular plasmid DNA vectors useful both for the biological amplification of the DNA and for the securing of recombinant expression of the DNA of proteins having IMPDH biological activities in prokaryotic and, especially, eukaryotic, host cells and organisms.
Well-known recombinant means for introducing genes into host cells and organisms have been described. For example, Palmiter, et al., Science , 222:809 (1983), have described transgenic mice containing the human growth hormone gene fused to a promoter sequence. Maclean, N., et al., Bio/Tech ., 5:257 (1987), have produced transgenic fish. Caplan, A., et al., Science , 222:815-821 (1983), described the use of a modified plasmid for use as a vector to transfer foreign genes into plants. More recently, Sinkar, V. P., et al., Genes & Development , 2:688-697 (1988), described transgenic tobacco plants. These recombinant means are expected to allow for the production of plant or animal organisms into which IMPDH encoding DNA has been introduced and which therefore contain increased endogenous levels of guanosine-5′-monophosphate (GMP). GMP, a natural constituent of all living materials and normally present only in trace amounts, is a member of a family of flavor potentiators commonly used as food additives. GMP enhances the taste intensity of certain flavors and can suppress the perception of a sour or bitter taste. [Heath, et al., “Flavor Chemistry and Technology”, AVI Publishing Co., Westport, Conn., (1986)]. When combined with the commonly used food additive, monosodium glutamate, GMP acts synergistically to enhance flavor and it is therefore possible to enhance the taste properties of certain foods by increasing the endogeneous GMP levels. Organisms with increased levels of GMP can also provide a ready source for the isolation and extraction of GMP for use as a food additive. Studies of tissue culture cells with altered levels of IMPDH activity show an association between increased IMPDH activity and elevated GMP levels. [Ullman, J. Biol. Chem ., 258:523-528 (1983)]. Thus, selection for an organism with increased levels of IMPDH activity simultaneously selects for organisms with elevated tissue levels of GMP.
Microinjection and other transformation techniques are expected to readily allow for incorporation of extra copies of IMPDH encoding DNA into host cells and organisms, with exposure of the cells and organisms to inhibitors such as MPA providing a basis for selection of those cells having incorporated the desired sequences.
Cells and organisms having enhanced IMPDH production levels are, of course, also made available according to the present invention by means of the screening and selection procedures applied in Example 1. Briefly, a selected somatic or embryonic cell type is (either with or without prior exposure to mutagenic influences) screened in culture for the capacity to survive in the presence of elevated levels of an inhibitor such as MPA. Cells capable of surviving in the screening environment, e.g., at levels of MPA of 0.5 to 1.0 μL/mL, are thereafter subjected to stepwise incremental selection at much higher levels of the inhibitor. The resulting cells and organisms having enhanced IMPDH synthetic capacity vis-a-vis parent cells will also be expected to display enhanced capacity for synthesis of GMP.
Among the additional forms of DNA provided by the invention are those that encode allelic variants of the specific mammalian IMPDH protein of FIG. 1A, FIG. 1B, FIG. 1C, FIG. 1D, FIG. 2A, FIG. 2B, FIG. 2C, and FIG 2 D, as well as analog proteins that possess one or more variations in IMPDH biological activities.
Protein and peptide products of the invention include not only those produced as recombinant expression products of “full-length” and fragmentary DNA sequences of the invention but also those that are prepared by chemical synthesis from amino acids. As one example, analysis of the deduced amino acid sequences of IMPDH proteins is expected to provide valuable information concerning potential antigenic epitopes present therein, allowing for the preparation of synthetic antigenic peptides duplicative of about 6 to 20 continuous residues of the protein. These, in turn, are expected to allow for the preparation of monospecific polyclonal and monoclonal antibodies useful in the quantitative detection of IMPDH proteins. Further, it is ancipated that the deduced amino acid sequences information can be used to modify existing drugs and to design new drugs as inhibitors of IMPDH activity.
Numerous modifications and variations in the invention as described in the above illustrative examples are expected to occur to those skilled in the art; consequently, only such limitations as appear in the appended claims should be placed thereon.
Accordingly, it is intended in the appended claims to cover all such equivalent variations that come within the scope of the invention as claimed.
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Disclosed are purified and isolated DNA sequences encoding eukaryotic proteins possessing biological properties of inosine 5′-monophosphate dehydrogenase (“IMPDH”). Illustratively, mammalian (e.g., human) IMPDH-encoding DNA sequences are useful in transformation or transfection of host cells for the large scale recombinant production of the enzymatically active expression products and/or products (e.g., GMP) resulting from IMPDH catalyzed synthesis in cells. Vectors including IMPDH-encoding DNA sequences are useful in gene amplification procedures. Recombinant proteins and synthetic peptides provided by the invention are useful as immunological reagents and in the preparation of antibodies (including polyclonal and monoclonal antibodies) for quantitative detection of IMPDH.
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BACKGROUND AND SUMMARY OF INVENTION
This invention relates to label-providing log for facsimile transmissions and method and, more particularly, to a bound volume of paired superposed sheets which creates a log as information is entered on a detachable routing label.
With the tremendous increase in facsimile transmissions --normally referred to as "fax"messages--there has arisen a problem of record control. This is solved through the practice of the invention as well as providing a conveniently accessible paste-on label which eliminates the cost of sending a cover sheet and saves fax paper.
The invention, in its log aspect, includes a plurality of paired superposed sheets bound along one side to form a permanent log. The lower of each pair of sheets is constructed of self-contained paper so that printing or writing on the upper sheet carries through the lower sheet to present an image on the lower of the pair of sheets. The upper sheet of each pair has on its upper surface a release liner and above the release liner a plurality of labels equipped with pressure sensitive adhesive in contact with the release liner. These labels are identical and bear identifying indicia for fax transmission which includes the recipient, the sender, facsimile numbers of both, the date and the number of pages to be transmitted.
Other objects, advantages and details of the invention can be seen in the ensuing specification.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described in conjunction with an illustrative embodiment in the accompanying drawing, in which--
FIG. 1 is a top plan view, partially broken away, of a fax log embodying teachings of this invention;
FIG. 2 is a fragmentary top plan view of the log of FIG. 1 but with the cover open to reveal the arrangement of labels on the interior pages;
FIG. 3 is a perspective view of the inventive log in the process of being inscribed as part of the practice of the inventive method;
FIG. 4 is an enlarged fragmentary plan view of the upper portion of the log seen in FIG. 2 and with the identifying indicia set down;
FIG. 5 is a fragmentary exploded perspective view showing the parts of the label-providing upper sheet; and
FIG. 6 is a fragmentary perspective view of a fax machine in the process of using a label-equipped page of correspondence according to the teachings of this invention.
DETAILED DESCRIPTION
In the illustration given and with reference first to FIG. 1, the numeral 10 designates generally the inventive fax log which is seen to include a cover 11 advantageously constructed of white coated chip board, interior sheets 12 and a spiral binding 13.
The sheets are provided in pairs as can be initially appreciated from FIG. 2 where the upper sheet of a pair is designated 14 and the lower sheet is designated 15. The same designations are employed in FIG. 5 where it will be seen that the upper sheet carries a peelable label 16 while the lower sheet 15 has imprinted thereon the same information as on the upper sheet 14. In use (referring to FIG. 3) a cardboard sheet 17 is inserted under the lower sheet so as to prevent strike-through to the next pair of sheets, the upper one of which being designated 14'. Also seen in FIG. 3 is a writing instrument such as a ballpoint pen designated 18 which is employed to enter the particulars of a fax transmission. Typical information is seen in FIG. 4 where information 24 relating to the log number, time and department is entered in a block at the extreme left and then on the label 16 information indicia relating to the recipient and his or her fax number as at 18. Also, entered on the label is information indicia as at 19 relating to the name of the sender, his or her fax number and phone number. Finally, as at 20, information indicia is entered as to the date and the number of pages including the page to be equipped with the label.
Referring now to FIG. 5, it will be seen that the label 16 is equipped on its underside with a pressure sensitive adhesive as at 21. The label 16 is peelably mounted on the upper sheet 14 and, for the purpose of illustration, a portion 14a has been shown in separated form from the remainder of the upper sheet 14. The upper sheet 14 is constructed of paper having a release coating, generally a silicone, on its upper surface.
In the illustration given, the upper sheet 14 has releasably secured thereto fourteen labels and, when the labels have all been used, the sheet 14 can be detached via a line of perforation 22, and thrown away. It will be appreciated that all of the information entered on the various labels will have carried through to the lower sheet 15 which constitutes the permanent log. A permanent log is advantageous in providing a readily accessible, chronological record of fax transmissions so that for accounting purposes, for example, cost can be readily ascribed as well as providing an information reservoir should a particular fax transmission need to be identified.
FIG. 6 illustrates the mode of usage wherein the label 16 which has been removed from the sheet 14 has been applied to a page of correspondence 23--typically inserted into the fax machine with the typed face positioned downwardly--for fax transmission.
EXAMPLE
As an example of the fax log 10, I provide a cover constructed of white chip board having a weight of 16 pounds per ream of 2318 square feet (in 24×271/4" sheets). Each upper sheet 14 is available from RaFlatac under Catalog designation 36 lb. Laser RP-55K lb. face, 50 lb. liner. Each of the upper (and lower) sheets 14, 15 are sized 81/4"×11". The lower sheets available from Appleton under designation 16 lb. self-contained white blackprint are constructed of ragless paper having a weight of 16 pounds per ream of 1298.6 square feet with the upper surface equipped with a self-contained coating. The fax log 10 is equipped with a rear cover which advantageously is constructed of uncoated chip board. The entire log or booklet advantageously contains 25 pairs of sheets which, with 14 labels per sheet, provides sufficient labels for 350 fax transmissions.
OPERATION
In the practice of the invention, a letter is typed, for example, to Joe Johnson and then the particulars at the block 24 and the other blocks 18-20 filled in by the person in charge of fax transmission. The label 16 is then peeled away from the upper sheet 14 and installed on the letter to Joe Johnson after which it is transmitted as seen, for example, in FIG. 6.
When the labels have all been removed from one upper sheet 14, the sheet may be detached by tearing along the line of perforations 22 and thrown away with a permanent record remaining on the self-contained coated lower sheet 15.
For the next transmission, the divider board 17 preventing strike-through is removed from its position under the now completed lower sheet 15 and placed under the next adjacent lower sheet.
While in the foregoing specification a detailed description of an embodiment of the invention has been set down for the purpose of illustration, many variations in the details hereingiven may be made by those skilled in the art without departing from the spirit and scope of the invention.
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A label-log having pairs of sheets wherein the upper sheet has peelable labels and the two sheets constituting a carbonless system whereby information indicia as to sender, recipient, date and the like when entered on the upper sheet is permanently recorded on the lower sheet.
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BACKGROUND OF THE INVENTION
This invention relates to a method for automatic control of the voltage of an electrostatic filter at the breakdown limit by means of a time dependent increase of the filter voltage to breakdown and a subsequent breakdown dependent decrease.
A method of this general nature is described for example in German Patent Application DE-AS No. 11 48 977.
The degree of separation of an electrostatic separator is higher, the closer the operating voltage is to the flashover limit. Since flashover limit varies during operation as a function of several factors, such as, for example, gas composition, dust content and temperature, the voltage of the electrostatic separator must be regulated as a function of the level of the flashover limit.
In the method according to the above mentioned DE-AS No. 11 48 977, a control capacitor is charged across a resistance as a function of the filter current. A continuously variable tube which in turn is energized by a capacitor is connected in parallel with this control capacitor as a discharging resistance. This capacitor is charged in a breakdown dependent manner and is discharged continuously via a parallel resistance. The voltage at the control capacitor is used as a control voltage for a final control element on the primary side. The current dependence of the charging voltage for the control capacitor is chosen so that at low separator current strengths a relatively rapid voltage increase is obtained, and at high separator current strengths a relatively slow one. Through the constant discharge of the control capacitor dependent on the flashovers, the separator voltage after flashovers is lowered by an amount given by the number or duration of the flashovers.
In this control method, the prior history of the breakdown just then present enters in the voltage decrease or respectively the increase up to the breakdown limit as a relatively minor or largely undefined factor.
SUMMARY OF THE INVENTION
It is the object of the present invention, in stationary operation in which the breakdown limit is continuously sampled as a function of time, to optimize the control method in such a way the one operates at the breakdown limit to the greatest extent possible while the number of breakdowns required for operating at this limit, during which actual separation is not possible, is maintained within predetermined limits.
According to the present invention, this problem is solved by reducing, after each breakdown, the voltage or the current by a percentage of the existing breakdown voltage or breakdown current which is dependent on the breakdown frequency during a preceding fixed period of time, and shortening the waiting time to a new voltage increase if the measured voltage amplitude at breakdown has increased relative to the measured voltage amplitude at the preceding breakdown, and vice versa.
In this manner the voltage is lowered by a percentage which is determined by the breakdown voltage on the one hand and by the prior history of the breakdown, on the other. Similarly, the waiting time is also fixed so that breakdowns will not be unduly frequent.
To attain defined conditions during increase to breakdown, the filter voltage is advantageously increased to breakdown at a fixed, preselectable voltage gradient which depends on the operational state of the installation.
If during the waiting time a breakdown occurs, the voltage increase planned at the end of the waiting time is advantageously omitted, but the new waiting time beginning at that moment is shortened.
It is thereby achieved that there will not be a succession of breakdowns in an uncontrolled number. To take into account the varying filter performance in relation to the waiting time, the waiting time is further advantageously variable in steps of different magnitude, e.g. the steps can be chosen in the form of a geometric series.
Since thyristors are presently normally used as control elements for electrostatic filters, and the phase angle control of these thyristors becomes noticeable on the d-c voltage side in a pulsation of the filter voltage, it is advantageously provided, in order to obtain defined points for the comparisons, to compare the crests of the voltage half-waves on the d-c voltage side immediately before the breakdowns.
In a device for carrying out the method according to the present invention where the electrostatic filter is fed from an a-c voltage source via a rectifier, a high voltage transformer, and a final control element, a microcomputer is advantageously provided for giving a set control voltage to the final control element. The microcomputer computes from the measured and stored filter data, the required reduction and the waiting time as well as other parameters.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the usual voltage supply for an electrostatic filter with a digital regulator operating by the method of the invention.
FIG. 1A illustrates the replacement of this digital regulator by a microcomputer system.
FIG. 2 illustrates the voltage conditions during sampling of the breakdown limit.
DETAILED DESCRIPTION
As can be seen from FIG. 1, an electrostatic filter 5 is fed from an alternating current network 1 via a rectifier and a high voltage transformer 3. On the primary side, between the high voltage transformer 3 and a-c network 1, an a-c controller 2 consisting of antiparallel connected thyristors is provided. A thyristor gate control unit 21 receives its control voltage U St from a digital regulator 6, shown framed by broken lines. Digital regulator 6 nowadays as a rule comprises the type of microcomputer system shown in FIG. 1A programmed to function as shown in FIG. 1. This microcomputer system includes as essential components, a central processing unit 81, a memory 82, and input/output devices 83 with which measured values and data can be obtained from and supplied to peripherals, e.g., A/D converters for I p and U F and D/A converters for supplying U St .
For better comprehension of the regulating process the digital regulator is shown in the form of permanently wired functional modules. This also constitutes a flow diagram which indicates the manner in which the microcomputer may be programmed.
As can be seen from FIG. 1, the control voltage U St is supplied by a control module 61, which determines the filter voltage U or respectively the filter current I. The gradient for the increase in filter voltage to breakdown is set by module 63. The set value for this gradient is taken out of a memory 62 depending on the operating conditions of the filter. When the filter voltage reaches the breakdown value, which is determined from the primary current I p and/or the collapse of the voltage U F on the secondary side, a breakdown detection element 70 sends, via a percentage setter 66 and a voltage reducing element 65 a corresponding voltage reduction command to the voltage control unit 61. The amount of reduction in case of breakdown is calculated from:
U=XnU.sub.F /100 or I=XnI.sub.F /100
X being a value between 0.2 and 1; n, the reduction step; and U F , the prevailing filter voltage. The equivalent applies if instead of a filter voltage reduction a filter current reduction I of the filter current I F is effected. The value n results from the prior history of the filter; it depends on the number k of breakdowns during a preceding seek period of, e.g., 10 to 30 minutes. If the number k of breakdowns not caused by the sampling of the filter voltage limit is greater than a preselectable limit value k g of, e.g., 1000, the reduction step n is increased and a new seek period begun. Then the reduction amounts Δu are calculated and stored. If the number of breakdowns in the seek period is smaller than the limit value k g , the reduction step n remains at first unchanged. If in the following seek period k is again smaller than k g , the reduction step n is decreased. Thereafter the new prevailing reduction amounts Δu are again calculated and stored. To adapt to changing operating conditions, the waiting time T to a new increase of the filter voltage is also varied as a function of breakdown, that is, the value of the breakdown voltage U Fv deposited in a memory 69 during the preceding breakdown is compared with the prevailing breakdown voltage U Fa . If it is found that the measured voltage amplitude at breakdown has increased relative to the measured voltage amplitude at the preceding breakdown, then by means of the comparator 68 the waiting time is shortened by the amount ΔT in the time changer element 67. This amount ΔT then correspondingly changes the waiting time T of the waiting stage 64. The waiting times are graded, for instance, in a geometric series. If the comparisons show, for instance, that the prevailing breakdown voltage is always higher than the preceding breakdown voltage, then the waiting times are shortened by amounts ΔT which for instance increase in a geometric series. The reverse applies if the values are always lower. If during the waiting time at least one breakdown occurs, the voltage increase planned at the end of the waiting time is omitted, but the waiting time beginning at that moment is also shortened by the amount ΔT after the prevailing variation stage.
FIG. 2 shows the voltage waveforms at the filter. As can be seen, due to the phase-angle control and the rectifiers, pulsating half-waves appear at the filter on the secondary side. If at point D1 a provoked breakdown occurs, the filter voltage U F will at first collapse, and then the returning filter voltage is reduced by an amount Δu which can be calculated with the above-stated equation. Then follows a waiting time T until the moment S, from which time on the filter voltage U F is again increased to the provoked breakdown D2, whereupon the voltage U F is lowered again by an amount Δu.
As it is relatively difficult to determine the actual breakdown voltage because of the pulsation of the voltages, the voltage comparison values determining for the waiting time are determined from the crests of the voltage half-waves just before the breakdowns. To this end the crest values are picked up and stored continuously, using for the comparison those values (e.g. U Fa , U Fv ) which immediately precede the breakdown.
In the above-described manner, one obtains an optimum control of the filter voltage at the breakdown limit.
The microcomputer may be any one of those currently available such as Motorola 6805, Intel 8080A, Z-Log Z-80, etc.
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A method for controlling the voltage of an electrostatic filter at the breakdown limit in which, when a breakdown occurs, the voltage is reduced by an amount which is determined by the breakdown voltage and the prior history of the breakdown and the waiting time to the next increase of the filter voltage is made dependent on the ratio of the voltages at successive breakdowns by comparing voltage amplitudes which immediately precede the breakdowns.
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FIELD OF INVENTION
This invention relates to an apparatus for enhancing the lateral movement of a trigger bar in a semi-automatic firearm when a trigger reset event occurs. In particular, this invention relates to enhancing the mechanical impact between a trigger bar and a sear as a firearm trigger is released.
BACKGROUND OF THE INVENTION
A striker-type fire control mechanism is commonly used in modern semi-automatic pistols. In striker fired pistols, the trigger is connected to a trigger bar. Movement of the trigger causes movement of the trigger bar, which in turn causes a sear to rotate about a pivot point. Upon rotation of the sear, a spring is compressed and an upper portion of the sear is displaced relative to the firing pin. Upon displacing the sear a sufficient distance to clear a depending leg of the firing pin, the firing pin is urged forward by a spring and strikes the rear of the cartridge, thereby discharging the firearm. After the firearm discharges, the trigger must be released forward to a point where the trigger bar re-engages the sear, resetting the trigger for the next shot.
In some firearms, the trigger reset is aided by a single tensioning coil spring located forward of the magazine channel. This trigger return spring performs the dual role of returning the trigger to a forward position and pulling the rear end of the trigger-bar back under the sear. During the forward return of the trigger bar, but before re-engagement with the sear, the trigger bar is laterally displaced out of cooperation with the sear such that the firearm may not yet be fired. As the trigger bar continues to move forward, the rear end of the trigger bar is pulled back under the sear, re-engaging the sear so that the firearm is again ready to fire.
The mechanical impact that occurs between the trigger bar and sear upon re-engagement physically communicates to the operator, through the operator's finger on the trigger, that the trigger reset is complete and that the firearm may be fired, i.e., that the firearm is set to fire when the trigger is pulled back again. However, because this mechanical impact can be slight, the physical communication to the operator through the trigger is subtle, and thus it can be difficult for a firearm operator to ascertain when trigger reset has occurred.
BRIEF SUMMARY OF THE INVENTION
Several embodiments of the present invention answer the above and other needs by providing a reset assist mechanism for biasing the trigger bar as the reset event occurs.
In one embodiment, the invention may be characterized as a reset apparatus for use in a firearm, comprising: a compression spring; a biasing member comprising a first end and a distal end wherein the compression spring is attached proximate to the first end of the biasing member; a notch disposed on the biasing member for cooperation with a trigger bar, wherein the trigger bar comprises a longitudinal axis defined by a front portion and a rear portion, wherein the front portion is mechanically cooperated with a firearm trigger; and wherein the compression spring communicates a force through the biasing member and onto the trigger bar in a direction substantially perpendicular to the longitudinal axis of the trigger bar.
In another embodiment, the invention may be characterized as method for signaling a trigger reset event comprising: attaching a compression spring to a biasing member, the biasing member comprising a first end and a distal end wherein the compression spring is attached proximate to the first end of the biasing member; disposing the biasing member to be in mechanical cooperation with a trigger bar, wherein the trigger bar comprises a front portion and a rear portion, the front portion being mechanically cooperated with a firearm trigger; applying a force from the biasing member onto the trigger bar in a direction substantially perpendicular to an axis of the trigger bar (longitudinal axis of the trigger bar, or longitudinal firing axis), the axis defined by the front and rear portions of the trigger bar.
In yet another embodiment, the invention may be characterized as a means for magnifying an impact resonance between a sear body and a trigger method for use with a modular irrigation controller comprising: a compression spring; a biasing member, the biasing member comprising a first end and a distal end wherein the compression spring is attached proximate to the first end of the biasing member; a notch disposed on the biasing member for cooperation with a trigger bar, wherein the trigger bar comprises a longitudinal axis defined by a front portion and a rear portion, wherein the front portion is mechanically cooperated with a firearm trigger; and wherein the compression spring communicates a force through the biasing member and onto the trigger bar in a direction substantially perpendicular to the longitudinal axis of the trigger bar.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other aspects, features and advantages of several embodiments of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings:
FIG. 1 is a simplified schematic perspective view of a fire control mechanism according to an embodiment of the present invention;
FIG. 2 is a simplified schematic perspective view of the sear of FIG. 1 ;
FIG. 3 is a simplified schematic perspective view of the engagement of the sear and a trigger bar of the fire control mechanism;
FIG. 4 is a simplified schematic view of the fire control mechanism of FIG. 1 ;
FIG. 5 is a simplified schematic view of the fire control mechanism in which the trigger bar is displaced away from the sear;
FIG. 6 is an enlarged perspective view of a biasing member of one embodiment of the present invention;
FIG. 7 is a side view of the biasing member of one embodiment of the present invention in which the biasing member is cooperated with a compression spring;
FIG. 8 is a left side view of the a sear housing block including a sear channel and an interior flange;
FIG. 9 is a right side view of the sear housing block including a channel and trigger bar (in this perspective view, a distal end of the biasing member is also shown);
FIG. 10 is a cut-away top view of the sear housing block in which the biasing member and the compression spring are mechanically cooperated with the trigger bar (the trigger bar is laterally displaced in the direction indicated by arrow D out of cooperation with cam portion 68 ; in this configuration, the compression spring 650 is compressed between the plunger head of biasing member and the sear flange such that a force is exerted on the trigger bar in the direction indicated by arrow F); and
FIG. 11 is a cut-away top perspective view of the sear housing block in which the biasing member and the compression spring are mechanically cooperated with the trigger bar (in this configuration, the trigger bar has been returned to its laterally unbiased position and is in cooperation with sear disposed under the cam portion).
DETAILED DESCRIPTION
The following description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of exemplary embodiments. The scope of the invention should be determined with reference to the claims.
Referring now to FIG. 1 , the fire control mechanism 18 includes a striker-type firing pin 19 having a forward firing pin portion 20 and a depending leg 22 extending down from the firing pin portion 20 . The fire control mechanism 18 also includes a sear assembly 26 that is engagable by the firing pin 19 . The sear assembly 26 is operably engagable with a trigger assembly that includes the trigger 28 . Upon operation of the handgun (via movement of the trigger 28 ), a surface of the depending leg 22 selectively engages the sear assembly 26 . The trigger 28 is pivotally connected to a trigger bar 30 via a pin 35 . The trigger bar 30 may be biased in lateral directions via a spring or the like. Rearward movement of the trigger 28 causes movement of the trigger bar 30 in a rearward longitudinal direction. When the trigger 28 is actuated by being pressed in a rearward direction, the trigger 28 pivots about a pin 38 , thereby transmitting rearward longitudinal movement to the trigger bar 30 via the pin 35 . Longitudinal movement of the trigger bar 30 in a rearward direction, in turn, actuates the sear assembly 26 , e.g., it unblocks the sear assembly, thereby allowing the firing pin 19 to translate in a forward direction under the action of a decompressing firing pin spring for the firing pin portion 20 to engage a cartridge and fire the handgun.
The fire control mechanism 18 is further described in U.S. Pat. No. 7,617,628 (Curry), the entirety of which is incorporated herein reference.
Referring now to FIG. 2 , in some embodiments the sear 50 is an elongated member having a major axis M. The elongated member is pivotal about the fulcrum 58 , which extends through the member in a direction that is substantially perpendicular to the direction in which the major axis M extends. The forward portion 59 of the sear 50 is configured to have both a ramp portion 67 and a cam portion 68 . From a side elevation, the cam portion 68 may have a cross-sectional configuration having an upper rounded surface 71 and a lower rounded surface 73 , both of which extend perpendicular to the direction in which the major axis M extends and parallel to the direction in which the pivot axis defined by the fulcrum 58 extends. The ramp portion 67 extends downward from the lower rounded surface 73 . A downward-facing surface of the ramp portion 67 is substantially flat. Both the forward portion 59 and the rearward portion are dimensioned and configured to have substantially the same masses relative to the fulcrum 58 . Thus, the sear 50 is substantially balanced front-to-back.
Referring now to FIG. 3 , the dimensions and configuration of the sear 50 are such that the lower rounded surface 73 on the cam portion 68 acts cooperatively with the trigger bar 30 . In particular, the lower rounded surface 73 engages a corresponding sloped surface 75 on the trigger bar 30 such that as the trigger is pulled, the trigger bar 30 moves rearward in the direction of an arrow A and in a plane that is at least partially coplanar with a plane in which the sear 50 rotates. In doing so, the sloped surface 75 on the trigger bar 30 engages the lower rounded surface 73 of the cam portion 68 , the sear 50 is rotated in the direction of an arrow B, and the forward end of the sear 50 is urged upward, thereby causing the rearward surface 60 to move downward about the fulcrum 58 . At a pre-selected distance, the sear 50 is pivoted fully downward against the sear spring to allow the leg 22 of the firing pin 19 to disengage from the rearward surface 60 .
Referring now to FIG. 4 , the depending leg 22 of the firing pin 19 is engaged by the sear 50 . As the trigger is pulled in the rearward direction, the trigger bar 30 likewise moves rearward, and the sloped surface 75 on the trigger bar 30 engages the lower rounded surface 73 of the sear 50 to urge the front of the sear 50 up and the rearward surface down (the sear 50 is pivoted about the fulcrum 58 ). The firing pin 19 is released and travels forward. The trigger bar 30 is fully extended in the rearward direction.
Referring now to FIG. 5 , after the trigger has been released, the trigger bar 30 likewise moves forward and also laterally out of registration with the sear 50 . Once the trigger bar 30 has moved sufficiently in the forward direction, the sloped surface 75 reengages the lower rounded surface 73 on the cam portion 68 of the sear 50 . The trigger bar 30 may be provided with a track or guide 89 in the sear housing block 52 , for the purpose of laterally guiding the trigger bar 30 during lateral displacement. As should be appreciated, the connection of the trigger 28 , trigger bar 30 , and the sear assembly 26 is such that the trigger bar 30 can be laterally displaced when pressure is exerted on the trigger bar 30 in a direction that is perpendicular to the direction in which the longitudinal firing axis extends.
FIG. 6 , is perspective view of a biasing member 600 . Shown is a cylindrical rod 610 , a cylindrical plunger head 620 , a first end 630 , a distal end 640 , a compression spring 650 and a notch 660 .
The biasing member 600 is comprised of the cylindrical rod 610 with the cylindrical plunger head 610 of a greater diameter and disposed on one side of the cylindrical rod 610 . The top surface of the cylindrical plunger head 620 includes a surface forming the first end 630 of the biasing member 600 . At the opposite end of the rod 610 is the distal end 640 . The notch 660 is disposed in one surface of the cylindrical rod 610 nearer to the distal end 640 than the first end 630 of cylindrical plunger head 620 . The notch 660 is of a size and shape suited to accommodate the trigger bar 30 , such that the trigger bar 30 is at least partially laterally constrained, i.e., is not free to slide side-to-side independently of the biasing member 600 , within the notch 660 when the biasing member 600 is cooperated with the trigger bar 30 . The trigger bar 30 is not constrained longitudinally, i.e., is free to slide forward and backward independently of the biasing member 600 , within the notch 660 when the biasing member 600 is cooperated with the trigger bar 30 .
In operation, the biasing member 600 is cooperated with the trigger bar 30 via the notch 660 . That is, the trigger bar 30 sits within notch 660 such that the longitudinal axis of trigger bar 30 is substantially perpendicular to the longitudinal axis of the biasing member 600 and parallel to the firing axis (longitudinal firing axis). In this configuration, the trigger bar 30 is allowed to move in its forward and rearward longitudinal directions as it is not fixed to any point within the notch 660 on the biasing member 600 . The lateral axis of the trigger bar is substantially parallel to the longitudinal axis of the biasing member 600 and perpendicular to the longitudinal firing axis. In this configuration, the trigger bar 30 moves in its side-to-side lateral directions and is constrained within the notch 660 on the biasing member 600 .
FIG. 7 is a side orthogonal view of a biasing member 600 cooperated with a compression spring 650 . Shown is a rod 610 with a plunger head 620 , a first end 630 , a notch 660 , a distal end 640 and a compression spring 650 .
Fixed under the plunger head 620 , is the compression spring 650 such that the rod 610 is disposed within the inner circumference of the compression spring 650 . In this configuration, the compression spring 650 can be compressed against the plunger head 620 in response to lateral displacement of the trigger bar 30 such that movement of the rod 610 and the plunger head 620 causes compression of the compression spring 650 .
In operation, the notch 660 is cooperated with the trigger bar 30 such that the trigger bar 30 freely moves in the forward and backward longitudinal directions. However, the notch 660 will affect the motion of the trigger bar 30 in the lateral direction perpendicular to the longitudinal axis (longitudinal firing axis) of the trigger bar 30 . When lateral displacement of the trigger bar 30 occurs, the compression spring 650 compresses against the plunger head 620 and around the rod 610 , translating a lateral force into the trigger bar 30 via the notch 660 .
FIG. 8 is a left perspective view of a sear housing block 52 . Show is a trigger bar 30 , a sear housing block 52 , a sear channel 810 and a flange 820 .
The sear channel 810 is a cylindrical hole in the sear housing block 52 in a direction perpendicular to the longitudinal axis (longitudinal firing axis) of the trigger bar 30 . The diameter of the sear channel 810 is narrowed by the flange 820 disposed within the sear channel 810 and beneath the surface of the sear housing block 52 . The dimensions of the sear channel 810 and the flange 820 are such that the distal end 640 of the biasing member 600 can fit into the inner diameter of the flange 820 within the sear channel 810 . However, the diameter of the compression spring 650 is larger than the inner diameter of the flange 820 and yet smaller than the inner diameter of the sear channel 810 . Thus, when the biasing member 600 is inserted into the sear channel 810 , the compression spring of the biasing member presses up against the flange 820 permitting the rod 610 to move in the lateral direction relative to the longitudinal axis of the trigger bar 30 as the compression spring 650 is compressed or decompressed.
In practice, the biasing member 600 together with the compression spring 650 is inserted into the sear channel 810 . Because of the relative dimensions of the compression spring 650 and the rod 610 , the larger diameter compression spring cooperates with the flange 820 allowing the rod 610 to penetrate sear housing block 52 via the inner diameter of the flange 820 . Inside the sear housing block 52 , the trigger bar 30 cooperates with the notch 660 on the rod 610 such that when the trigger bar 30 moves in a lateral direction, a lateral force is imparted on the rod 610 via the notch 660 causing the compression or decompression of the compression spring 650 . Compression of the compression spring 650 occurs when the trigger bar 30 is moved laterally in a direction away from the left side of the sear housing block 52 . Upon compression of the compression spring 650 , the biasing member 600 exerts a force of opposite direction on trigger bar 30 . This force exerted by the biasing member 600 tends to restore the trigger bar 30 back into cooperation with the sear 50 .
FIG. 9 , is a right perspective view of a sear housing block 52 . Shown is a trigger bar 30 , a guide 89 and a distal end 640 of a biasing member 600 .
The biasing member 600 , is shown inserted into the sear channel 810 and mechanically cooperated with the trigger bar 30 such that the distal end 640 is visible from the right perspective view of the sear housing block 52 . The geometry of the guide 89 is such that the trigger bar 30 is moveable along its lateral axis.
In practice, when the trigger bar 30 is laterally displaced, the biasing member 600 exerts a restoring force on the trigger bar 30 , in a direction into the page, forcing the trigger bar 30 back into mechanical cooperation with the sear 50 .
FIG. 10 depicts a top perspective cut away view of the sear housing block 52 , wherein the biasing member 600 is fully inserted into the sear channel 810 and mechanically cooperated with the trigger bar 30 and wherein the trigger bar 30 is displaced laterally out of cooperation with cam portion 68 . Shown is the distal end 640 , the rod 610 , the cam portion 68 , the compression spring 650 , the plunger head 620 , the first end 630 , the flange 820 and the frame 110 .
In this configuration, the cam portion 68 , the biasing member 600 and the trigger bar 30 are all disposed within the sear housing block 52 . The cam portion 68 is elevated above the trigger bar 30 which is in turn disposed above the biasing member 600 . Mechanically cooperated, the trigger bar 30 and the biasing member 600 are laterally displaced in the direction of arrow D such that plunger head 620 is pulled into sear channel 810 . Lateral displacement of the trigger bar 30 and the biasing member 600 results in compression of compression spring 650 against flange 820 .
In practice, after a shot has been fired, the trigger bar 30 is pulled in the forward longitudinal direction, indicated by arrow T, by a trigger return spring (not depicted) that is located forward of the magazine channel. During this forward return, the trigger bar 30 is laterally displaced out of cooperation with the cam portion 68 of the sear 50 . While the trigger bar 30 is laterally displaced out of cooperation with the sear 50 , the firearm may not yet be fired. Due to the mechanical cooperation between the trigger bar 30 and the biasing member 600 , the lateral displacement of trigger bar 30 results in a corresponding lateral displacement of the biasing member 600 with respect to the longitudinal axis (longitudinal firing axis) and in the direction of arrow D. The displacement of the biasing member 600 in turn causes the compression of the compression spring 650 between the plunger head 620 and the flange 820 such that the compression spring 650 exerts a force on the plunger head 30 in the direction indicated by arrow F. This force is translated along the rod 610 and into the trigger bar 30 so that the trigger bar 30 is also forced in the lateral direction of arrow F. This restoring force will tend to return the trigger bar 30 under the cam portion 68 such that the trigger bar 30 is re-cooperated with the sear 50 . Upon reengagement with the sear 50 by the trigger bar 30 , the trigger reset event will be complete, allowing the fire to be fired.
Absent the biasing member 600 of the present embodiment, a stock firearm relies on the forward force provided by a trigger return spring in the direction of arrow T in order to both laterally restore the trigger bar 30 into cooperation with the sear 50 and return the trigger to a forward position. Thus, in the event that the trigger return spring were to malfunction, trigger reset would be difficult because there is no method with which to re-position the trigger bar 30 beneath the cam portion 68 such that the trigger bar 30 and the sear 50 are mechanically cooperated. However, with the present embodiment, due to the lateral force imparted on the trigger bar 30 by the biasing member 600 , the trigger bar 30 maintains a relationship with the cam portion 68 . As such, trigger reset can be accomplished so long as the firearm operator is able to manually restore the trigger 28 to a forward position.
FIG. 11 depicts a top perspective cut away view of the sear housing block 52 , wherein biasing member 600 is inserted into the sear channel 810 and mechanically cooperated with the trigger bar 30 and wherein the trigger bar 30 is mechanically cooperated with the cam portion 68 . Shown is a distal end 640 , a rod 610 , a cam portion 68 , a compression spring 650 , a plunger head 620 , a first end 630 , a flange 820 and a frame 110 .
In this configuration, mechanically cooperated, the trigger bar 30 and the biasing member 600 are laterally restored such that the trigger bar 30 is re-cooperated with the sear 50 . As such, the compression spring 650 is disposed between the flange 820 and the plunger head 620 and is uncompressed. In this position, the first end 630 of the plunger head 620 is in contact with the interior frame surface 110 .
In practice, it is the impact resonance that occurs between the trigger bar 30 and the sear 50 upon re-engagement, that physically communicates to the operator, that the trigger reset (trigger reset event) is complete, i.e., that the firearm may be fired. However, in firearms lacking the benefits of the present embodiment, the mechanical impact between the trigger bar 30 and the sear 50 upon re-engagement can be so insignificant, that it is often difficult for an operator to ascertain when the re-cooperation has occurred, i.e., when the trigger reset has completed. More specifically, in most stock firearms, there is only one lateral force exerted on the trigger bar 30 that originates from the trigger return spring. However, the trigger return spring, located forward of the magazine channel, is too distant from the location of the trigger reset event to cause an appreciable mechanical impact as the trigger bar 30 rejoins the sear 50 .
The biasing member 600 of the present embodiment serves to enhance the mechanical impact between the trigger bar 30 and the sear 50 without adversely affecting the trigger pull weight. As the trigger bar 30 moves in the forward longitudinal direction of arrow T, the lateral displacement of the trigger bar 30 is corrected by both the lateral restoring force imparted by biasing member 600 and the lateral force due to the effects of the trigger return spring. That is, in some embodiments, the trigger bar 30 receives a lateral restoring force from two independent sources, the trigger return spring and the biasing member 600 . The addition of the lateral force contributed by biasing member 600 enhances the mechanical impact between the trigger bar 30 and the sear 50 as the trigger bar 30 and the sear 50 reconnect. This added force in turn enhances the impact resonance at the trigger reset event, allowing an operator to more easily ascertain when the reset even has occurred. Furthermore, the longitudinal movements of the trigger bar 30 are not significantly impeded by the mechanical cooperation with the notch 660 of the biasing member 600 . Because the trigger bar 30 is allowed to slide freely in the forward and rearward longitudinal directions within the notch 660 , the mechanical cooperation of the trigger bar 30 and the biasing member 600 does not impact the trigger pull weight.
Additionally, a secondary impact resonance is created between the first end 630 of the biasing member 600 and the interior surface of the frame 110 . As the compression spring 650 decompresses and the trigger bar 30 is laterally biased back into cooperation with the sear 50 , the biasing member 600 is also laterally biased, in the direction opposite of arrow D, such that the plunger head 620 re-emerges from the sear channel 810 such that the first end 630 of the plunger head 620 contacts the interior of the frame 110 . This mechanical impact contributes a secondary impact resonance to the operator, facilitating an indication of when the trigger reset event has occurred.
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A reset apparatus for use in a firearm, comprising: a compression spring; a biasing member has a first end and a distal end wherein the compression spring is attached proximate to the first end of the biasing member; a notch disposed on the biasing member for cooperation with a trigger bar, wherein the trigger bar comprises a longitudinal axis defined by a front portion and a rear portion, wherein the front portion is mechanically cooperated with a firearm trigger; and wherein the compression spring communicates a force through the biasing member and onto the trigger bar in a direction substantially perpendicular to the longitudinal axis of the trigger bar.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a technique which allows conducting a doping process or other chemical and physical treatments efficiently even at a low temperature.
[0003] 2. Prior Art
[0004] Known processes for doping semiconductors with impurities include a diffusion process and an ion implantation process. The diffusion process comprises heating the semiconductor to a high temperature in the range of from 1000 to 1200° C. to make the impurities diffuse into semiconductors. In an ion implantation process, a predetermined portion of a semiconductor is bombarded with an ionized impurity which has been accelerated in an electric field.
[0005] The diffusion coefficient D of an impurity can be expressed with an exponential function of absolute temperature T as D=D 0 ·exp[−E a /kT], where D 0 is the diffusion coefficient at T=∞, E a is the activation energy, and k is the Boltzmann constant. This equation describes the increase of diffusion coefficient with elevating temperature; accordingly, it has been common practice to carry out diffusion at temperatures as high as possible, preferably, at 1000° C. or higher. In the ion implantation process, on the other hand, it is necessary to activate the impurity and to remove the defects in the crystal lattice damaged by the ion bombardment; i.e., the implantation is followed by high-temperature annealing in the temperature range of from 600 to 950° C.
[0006] Recently, some types of active-matrix liquid crystal display devices using a thin-film transistor (TFT) provided on a glass substrate as the switching device have brought into practical use. The source and drain regions in the TFTs of those display devices are, in general, formed monolithically with the ohmic contacts using amorphous silicon having either of the N-type and P-type conductivity. Because the TFT used in this case is of an inverse stagger type, it likely produces a parasitic capacitance ascribed to its structure. To prevent this unwanted capacitance from developing, there has been made studies on making use of a TFT having its source and drain being formed in a self-aligned structure. However, the source and drain can be formed in a self-aligned manner only by the use of an ion implantation or ion shower process. Then again, a post annealing at the temperature range of from 600 to 950° C. should be carried out to activate the impurities and to recover the damage. Taking into consideration that the general purpose economical glass resists only up to a temperature of about 600 to 700° C., those ion implantation and ion shower processes are not feasible in an industrial operation.
[0007] As another means to circumvent the problem concerning the recover of thermal damage on the glass substrates, there is known a technology, i.e., impurity doping using a laser beam irradiation. There is known, for example, a process which comprises first covering the intended portion of the surface of the semiconductor with a thin film of the impurity, and then irradiating a laser beam thereto to melt the thin film of the impurity simultaneously with the surface of the semiconductor. In this manner, it is possible to dissolve the impurity into the surface of the molten semiconductor.
[0008] In the process above using an excimer laser beam irradiation, the impurity doping can be carried out without causing thermal damage on the glass substrate. However, the process requires an additional step of coating the semiconductor with the impurity. Conventionally, a coating process such as spin coating has been used for this step. However, the quality of this coating is process-determining, because the concentration of the doped impurity depends on the evenness of this coating. Thus, this process is far from being an ideal one. Furthermore, this coating is formed generally using an organic solvent as the solution medium. The use of such an organic solvent sometimes allows unfavorable elements such as carbon, oxygen, and nitrogen to enter into the semiconductor to impair the properties thereof.
[0009] In the light of the circumstances described above, the present invention has been achieved with an aim to provide a laser-beam doping technology using particularly an excimer laser, said technology being composed of simplified process steps and free from invasion of foreign elements into the semiconductor during the process. Accordingly, the present invention provides, with an object to simplify the process and to prevent inclusion of undesirable elements, a doping process using a high purity doping material in its gas phase in the place of the conventional solid or liquid phase doping materials. It is another object of the present invention to increase the doping efficiency.
[0010] Still other objects of the present invention include doping of elements into, in addition to semiconductors, various types of materials inclusive of insulators and conductors, as well as modifying materials and surfaces thereof. There can be specifically mentioned, for example, doping of phosphorus into a silicon oxide film.
SUMMARY OF THE INVENTION
[0011] The present invention provides an impurity doping process for imparting either of the N-type and P-type conductivity to the sample semiconductor, which comprises irradiating a laser beam to the surface of a semiconductor sample in a high purity reactive gas atmosphere containing an impurity which renders the semiconductor N-conductive or P-conductive. It is known, however, based on the acquired knowledge of the present inventors, that the process at temperatures as low as the room temperature is yet to be improved to achieve sufficient diffusion of the elements. In the process of the present invention, the laser beam is irradiated to the semiconductor with the semiconductor being maintained at a temperature higher than room temperature.
[0012] An embodiment according to the present invention provides, accordingly, a process which comprises heating the sample and maintaining it to at least 200° C. during the irradiation of a laser beam, thereby accelerating diffusion of the impurity elements and to dope the semiconductor with the impurity at a high concentration. The temperature to which the substrate is to be heated depend on the type of the semiconductor, and is in the range of from 250 to 500° C., preferably from 300 to 400° C., in the case of polysilicon (polycrystalline silicon) and semi-amorphous silicon.
[0013] Thus heating the semiconductor is not only advantageous for the diffusion of the impurities, but also the semiconductor itself more readily recovers the temporarily lost high crystallinity due to laser beam irradiation, because heating the sample provides thermally a sufficient relaxation time. A sample without being heated and subjected to an irradiation of a laser beam, particularly to a beam of a laser operating in a pulsed mode, experiences a typical rapid heating and rapid cooling. Hence, such samples are apt to turn into an amorphous state. More specifically, the sample is instantaneously heated to a temperature as high as 1000° C. or even higher, but is then cooled to room temperature during the next period of several hundreds of nanoseconds. If we consider a case in which the sample is silicon and in which the sample is heated to the temperature range above, the time necessary to reach the lower limit of the crystallization temperature, i.e., about 500° C., is calculated to be 10 times as long as that necessary to cool the sample to room temperature. If the duration of laser beam irradiation exceeds a certain duration at this step, the silicon melts to develop a convection which carries the impurities deep into the internal of the silicon. On the other hand, if a pulsed laser beam does not endure for a certain time, the silicon crystallizes into a solid to give a so-called semi-amorphous phase. In this case, the impurities undergoes solid-phase diffusion to enter the internal of the silicon.
[0014] It is unfavorable to heat the semiconductor to an excessively high temperature. At too high a temperature, the reactive gas itself undergoes pyrolysis (decomposition by heat) to form deposits not only on the sample but also on the holder and the like. As a result, the efficiency of gas usage may be greatly impaired.
[0015] It is also undesirable to maintain the semiconductor at a temperature higher than the crystallization temperature thereof. This is particularly so in the case of semiconductors comprising defects at high density, such as polycrystalline semiconductors, amorphous semiconductors, and semi-amorphous semiconductors. If the doping were to be taken place on a crystalline semiconductor being heated to a temperature of crystallization temperature or higher, the control for valence electrons is almost lost due to the generation of energy levels. Accordingly, it is preferred that the process is conducted by heating the substrate at a temperature not higher than the temperature at which amorphous silicon undergoes thermal transition to polysilicon, i.e., from 500 to 550° C., and more preferably, at a temperature not higher than a temperature lower than the transition temperature by 100° C. (i.e., about 400 to 450° C., or lower). In the case of a TFT using amorphous silicon (referred to hereinafter as a-Si:TFT), the device is destroyed if the temperature exceeds 350° C. Thus, such a-Si:TFTs should be maintained at a temperature lower than 350° C. Such a care should be taken to other semiconductors as well.
[0016] Another embodiment according to the process of the present invention provides a technology for doping of an impurity from a gas phase using a laser, particularly an excimer laser, in which a plurality of elements are doped using different types of doping gases. An object of the present process using a single laser beam is to avoid the drop in doping efficiency due to the use of various doping gases differing in light absorption properties and in decomposition behavior. Accordingly, in the present process comprising irradiating a laser beam to the sample in a reactive gas atmosphere containing an impurity which imparts either of the N- and P-conductive types to the semiconductor, an electromagnetic energy is applied to said reactive gas simultaneously with the laser irradiation to thereby decompose the reactive gas. The doping efficiency can be further improved by heating the semiconductor to a pertinent temperature in the same manner as in the first embodiment of the present invention. For example, this heating is carried out at a temperature not higher than the crystallization temperature of the semiconductor under the application of the electromagnetic energy.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 shows schematically the steps of a process for fabricating a TFT as described in the examples;
[0018] FIG. 2 shows schematically the steps of a process for fabricating a TFT as described in the examples;
[0019] FIG. 3 shows schematically the steps of a process for fabricating a TFT as described in the examples;
[0020] FIG. 4 shows schematically the steps of a process for fabricating a TFT as described in the examples;
[0021] FIG. 5 shows a schematically drawn apparatus used in Example 1, used for processing (impurity-doping) semiconductors;
[0022] FIG. 6 shows another schematically drawn apparatus used in Example 2, used for processing (impurity-doping) semiconductors;
[0023] FIG. 7 shows another schematically drawn apparatus used in Example 3, used for processing (impurity-doping) semiconductors;
[0024] FIG. 8 shows another schematically drawn apparatus used in Example 4, used for processing (impurity-doping) semiconductors;
[0025] FIG. 9 is a graph showing the distribution of impurity regions in semiconductors having fabricated by a conventional process and a process according to the present invention;
[0026] FIG. 10 shows schematically the steps of a process for fabricating a TFT as in Example 5;
[0027] FIG. 11 shows schematically the steps of a process for fabricating a TFT as in Examples 6 and 7;
[0028] FIG. 12 is a graph showing the C-V characteristics of a TFT having fabricated in an Example;
[0029] FIG. 13 is a graph showing the distribution of an impurity (boron) along the thickness direction;
[0030] FIG. 14 is a graph showing the distribution of an impurity (phosphorus) along the thickness direction;
[0031] FIG. 15 is a graph in which the change in sheet resistance with varying applied energy density is plotted; and
[0032] FIG. 16 gives the characteristic curves for an inverter and a ring oscillator having fabricated by a process according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0033] In the process according to the present invention, the impurity which imparts either of the N- and P-conductive types to the semiconductor refers specifically to, in the case where a silicon semiconductor is used, a trivalent element, representatively boron (B) and the like, to impart a P-type conductivity; and, a pentavalent impurity, representatively phosphorus (P), arsenic (As), etc., to impart an N-type conductivity to the silicon semiconductor. Examples of the reactive gases containing those impurities include AsH 3 , PH 3 , BF 3 , BCl 3 , and B(CH 3 ) 3 .
[0034] Most commonly used semiconductor for fabricating a TFT is a thin film of an amorphous silicon semiconductor having deposited by a vapor phase process, a sputtering process, etc. Also included are polycrystalline and single crystal silicon semiconductor films prepared from a liquid phase. Needless to say, semiconductors other than silicon can be used as well.
[0035] A laser beam having generated from an excimer laser apparatus operating in a pulsed mode is advantageously used. Laser beams in pulses is preferred because the sample can be instantaneously heated, and moreover, selectively heated only on the surface. This is advantageous because the substrate can be left intact. Because heating with a laser is confined to a small area of the sample, the use of a continuously operating laser (such as argon ion laser) sometimes causes the heated portion to fall off from the substrate due to considerable difference in thermal expansion coefficient between the substrate and the sample. In using a laser operating in a pulsed mode, however, this problem can be neglected because the thermal relaxation time is almost negligible as compared with the reaction time of a mechanical stress such as thermal expansion. Thus, the sample can be obtained without suffering any mechanical damage. Of course, there is little diffusion of impurities in the substrate.
[0036] What is more advantageous is that the excimer lasers emit ultraviolet (UV) radiations. Because silicon and other semiconductors are good absorbers of UV light, those can efficiently absorb the beam. The duration of a pulse is as short as 10 nsec. Furthermore, we can rely on an excimer laser considering the fact that it has been used in experiments for obtaining thin films of polycrystalline silicon having high crystallinity; the excimer laser has been irradiated on thin films of amorphous silicon for their crystallization. Specific examples of suitable excimer lasers include an ArF excimer laser (emitting light of wavelength 193 nm), a XeC 1 excimer laser (308 nm), a XeF excimer laser (351 nm), and a KrF excimer laser (248 nm).
[0037] In the process according to the present invention, the substrate is heated by using a conductive type holder in which a nichrome alloy wire, a kanthal alloy wire, or another heating element is directly assembled. Also useful are infrared-emitting lamps and any other of a radiation type. However, the temperature of the substrate should be precisely controlled, because the concentration and the depth of the doped impurities are greatly influenced by the temperature of the substrate. Thus, the use of a temperature sensor such as a thermocouple is indispensable for the temperature control of the sample.
[0038] In the process according to the present invention, the reactive gas (referred to hereinafter as a “doping gas”) for use in doping of impurities is decomposed by applying thereto, in general, a 13.56-MHz high frequency wave energy as an electro-magnetic energy. The use of this auxiliary electromagnetic energy enables doping at a high efficiency even when a laser beam which by itself cannot directly decompose the doping gas is used. The electromagnetic energy to use for this purpose need not be only a high frequency wave of 13.56 MHz, and also useful for obtaining a still higher activation ratio is, for example, a microwave at a frequency of 2.45 GHz. Still further, there can be taken advantage of an ECR (electron cyclotron resonance) condition which results from the mutual reaction between a 2.45-GHz microwave and a 875-Gauss magnetic field. It is also effective to use an optical energy which is intense enough to directly decompose the doping gas.
[0039] In the foregoing description, a technology for doping of impurities into a semiconductor was referred. The present invention, however, can be applied not only in the specified field above but also in a variety of fields. For example, the present invention can be used in adding a trace element to a metal for a mere several percent to a portion defined by a certain thickness from the surface, to thereby modify only the surface of the material. More specifically, nitrogen may be added to the surface of iron by conducting the process according to the present invention in ammonia, to obtain a surface comprising iron nitride for a thickness of from several to several hundreds of nanometers.
[0040] The present invention can be effectively applied to an oxide as well. For example, the process according to the present invention can be carried out on a thin film of a bismuth-based high temperature oxide superconductor in a lead chloride vapor, thereby adding lead into the oxide superconductor and hence elevate the critical temperature of the superconductor. Several types of bismuth-based oxide superconductors are known to exist, but the highest achieved critical temperature to the present is about 110 K. However, it is difficult to obtain phases having a critical temperature over 100 K. It is known also that the addition of lead into those superconductors readily provides phases with critical temperatures over 100 K, but in a practical process for fabricating thin films, lead tends to dissipate outside the oxide due to the heat from the substrate. In the process according to the present invention, however, the reaction takes place in disequilibrium. Hence, lead can be effectively incorporated into the material having deposited into a thin film. Similarly, the process can be applied to a lead-containing ferroelectric, PZT (lead zirconate titanate), which is now gaining much attention as a functional material for semiconductor integrated circuits, more particularly, for semiconductor memories.
[0041] The process according to the present invention can be used further for adding trace impurities into an insulator such as silicon oxide. Silicon oxide is frequently used as phosphosilicate glass (PSG) by adding several percent of phosphorus therein, as is customary in the conventional fabrication processes for semiconductors. Thus, phosphorus can be added to silicon oxide using the process according to the present invention; for example, phosphorus may be added to silicon oxide and diffused therein at a concentration of from 1×10 20 to 3×10 20 cm −3 .
[0042] The phosphosilicate glass is known for its ability of preventing movable ions such as sodium from invading the internal of the semiconductor. In a conventional process, the phosphosilicate glass is deposited as a film in an isolated CVD (chemical vapor deposition) chamber designed specially for PSGs. The installation of such a CVD chamber requires an additional cost. In contrast, the steps of doping of impurities and depositing phosphosilicate glass can be performed in a single apparatus for laser doping. Moreover, the film deposition apparatus for silicon oxide can be used widely in other applications. Accordingly, the total cost can be reduced, and hence, it can be seen that the process is economical.
[0043] In particular, the process according to the present invention is effective for improving film properties of the silicon oxide film having deposited at a relatively low substrate temperature of 600° C. or lower, using various types of organosilane compounds (e.g., tetraethoxysilane (TEOS)) as the starting material by vapor phase reaction. The process for doping the silicon oxide film comprises irradiating a laser beam to the surface of the silicon oxide film in a gas atmosphere containing phosphorus. In general, conventional films of this type contain considerable amount of carbon which impair the insulating properties; moreover, those films had too many trap levels to be used as insulator films for MOS structures and the like.
[0044] However, the film obtained by the process according to the present invention results in a considerably reduced amount of trap levels and in an improved insulating property. This is because carbon is driven away from the film by the heat having generated by the laser irradiation. As explained hereinbefore, the distribution of the impurities along the depth direction of the substrate can be controlled by changing the temperature of the substrate. Accordingly, if a silicon oxide film containing phosphorus deeply distributed therein is desired, the substrate is maintained at a temperature of 200° C. or higher, and preferably, in the range of from 350 to 450° C. If a silicon oxide film having phosphorus distributed within 100-nm depth or shallower, the substrate is maintained at a room temperature or lower.
[0045] If another semiconductor material such as amorphous silicon is provided under the silicon oxide film at the laser doping, the crystallinity thereof is also improved at the same time by annealing. This occurs because a silicon oxide film has low absorbance of UV light, and hence, the UV radiation having transmitted through the film is absorbed by the semiconductor material lying underneath the silicon oxide film. This signifies that two steps can be put simultaneously in progress, and that the process according to the present invention is useful for enhancing mass-productivity.
[0046] In FIGS. 5 and 6 are shown schematically the apparatuses according to the present invention. The apparatus illustrated in FIG. 5 is equipped only with a substrate heating device (sample heating device), and that in FIG. 6 comprises, in addition to the device above, an electromagnetic device for generating a plasma. It should be noted that the figures are intended only for explanatory use, and in the practical operation of those apparatuses, they must be implemented with other parts if necessary. The mode of usage of those apparatuses is described below.
[0047] Referring to FIG. 5 , explanation is made first on the apparatus shown therein. A sample 24 is mounted on a sample holder 25 . First, a chamber 21 is evacuated using an evacuation system 27 which is connected to an evacuation apparatus. This step is conducted because the atmospheric components such as carbon, nitrogen and oxygen are least desirable for semiconductors. Those elements are easily incorporated into the semiconductor to sometimes lower the activity of the intentionally added impurities. Furthermore, they also impair the crystallinity of the semiconductor and are causes of the formation of dangling bonds. Thus, the chamber is preferably evacuated first to a vacuum of 10 −6 Torr or lower, and preferably, to 10 −8 Torr or lower.
[0048] It is also favorable to drive out the atmospheric components having adsorbed inside the chamber by operating a heater 26 , together with, slightly before, or slightly after the evacuation. A structure, as is commonly seen in a present-day vacuum apparatus, is preferred that a pre-chamber is separately provided outside the chamber, because the chamber can be isolated from the atmosphere. As a matter of course, the use of turbo molecular pumps and cryo-pumps which cause less carbon contamination and the like is preferred to rotary pumps and oil-diffusion pumps.
[0049] After once the chamber is sufficiently evacuated, a reactive gas containing an impurity element is introduced into the chamber through a gas system 28 . The reactive gas may be a single component gas, or such diluted with hydrogen, argon, helium, neon, etc. It may be controlled to an atmospheric pressure or lower. These conditions are selected in view of the type of the semiconductor to be processed, the concentration of the impurity, the depth of the impurity region, the temperature of the substrate, and the like.
[0050] Then, a laser beam 23 is irradiated through a window 22 from a laser device. At this instance, the sample is heated to a constant temperature using a heater. The laser beam is irradiated, in general, from about 5 to 50 pulses per one site. Because the energy per pulse of the laser beam considerably fluctuates, too few a repetition leads to the production of undesirable products at a high possibility. On the other hand, too many a pulse repetition per site is also undesirable from the viewpoint of throughput. From the acquired knowledge of the present inventors, a pulse repetition of from about 5 to 50 per site is optimal from the viewpoint of throughput and product yield.
[0051] In irradiating a laser beam having a particular shape, for example, a 10 mm (along x direction)×30 mm (along y direction)-rectangle, the beam can be irradiated in a pulse repetition of 10 times per site and then it can be moved to the next site. Otherwise, the beam position can be moved 1 mm each time along the x direction with the repetition of the pulse.
[0052] Upon completion of the laser irradiation step, the interior of the chamber is evacuated to vacuum, and the sample is taken out of the chamber after sufficiently cooling it to room temperature. It can be seen that the doping step is quite easily performed, and yet rapid. This can be seen in clear contrast with a conventional ion implantation process which comprises three steps, i.e., (1) forming a doping pattern, which comprises coating the semiconductor with a resist, exposing, and developing; (2) conducting ion implantation (or ion doping); and (3) recrystallizing the resulting semiconductor; or with a conventional solid phase diffusion process which comprises also three steps, i.e., (1) forming a doping pattern, which comprises coating the semiconductor with a resist, exposing, and developing; (2) coating the resulting structure with an impurity film (by spin-coating, etc.); and (3) irradiating laser beam to the resulting structure. The process according to the present invention can be accomplished in two steps, i.e., (1) forming a doping pattern, which comprises coating the semiconductor with a resist, exposing, and developing; and (2) irradiating a laser beam to the resulting structure.
[0053] A description similar to that given for the apparatus shown in FIG. 5 can be applied to the one illustrated in FIG. 6 . Firstly, a chamber 31 is evacuated to vacuum through an evacuation system 37 , and then a reactive gas is introduced therein through a gas system 38 . Then, a laser beam 33 is irradiated to a sample 34 having mounted on a sample holder 35 through a window 32 . At this instance, an electric power is applied from a high frequency or an AC (or DC) power source 40 to an electrode 39 to thereby generate a plasma and the like inside the chamber to activate the gas. The electrode in the figure is illustrated as a capacitance coupling type, but an inductance coupling type may be used in its place without any problem. Furthermore, even if a capacitance coupling type were to be used, the sample holder may be used as the counter electrode. The sample may be heated with a heater 36 during irradiating thereto a laser beam.
[0054] The present invention is described in further detail below referring to some non-limiting examples.
EXAMPLE 1
[0055] An N-channel thin film gate-insulated field-effect transistor (referred to hereinafter as “NTFT”) established on a glass substrate was fabricated according to a doping process of the present invention. A glass substrate or a quartz substrate was used in this example. Such substrates were selected because the TFTs thus fabricated were intended for switching devices and driving devices of an active matrix liquid crystal display device or an image sensor. The process according to the present invention can be used as a doping technology in the fabrication of other semiconductor devices as well, such as the fabrication of P-type and N-type semiconductor layers of a photoelectric conversion devices, and the fabrication of single crystal semiconductor integrated circuits (ICs). In such cases, single crystal and polycrystalline substrates of silicon and other semiconductors can be used as well as other insulators.
[0056] Referring to FIG. 1 , the fabrication process is described. An SiO 2 film or a silicon nitride film was first deposited on a glass substrate 11 to give a base protective film. In the present example, a 200 nm thick SiO 2 film was deposited by RF sputtering in a 100% oxygen atmosphere under conditions as follows.
Oxygen flow rate 50 sccm Pressure 0.5 Pa RF power 500 W Substrate temperature 150° C.
[0057] Then, a 100 nm thick layer 13 of hydrogenated amorphous silicon semiconductor, which is intrinsic semiconductor or substantially intrinsic (without artificially adding any impurity), was deposited on the SiO 2 film by plasma-assisted CVD process. This layer 13 of hydrogenated amorphous silicon semiconductor serves as a semiconductor layer which provides a channel forming region and source and drain regions. The film deposition was conducted under conditions as follows.
Atmosphere 100% silane (SiH 4 ) Film deposition temperature 160° C. (substrate temperature) Pressure at film deposition 0.05 Torr Input power 20 W (13.56 MHz)
[0058] In the present process, silane was used as the starting material for depositing amorphous silicon. However, if the amorphous silicon is to be thermally crystallized into a polycrystalline silicon, disilane or trisilane may be used as alternatives to silane to lower the crystallization temperature.
[0059] The film deposition in this case was conducted in 100% silane instead of carrying out the process in a generally employed hydrogen-diluted silane atmosphere. This was based on experimental results which showed that the amorphous silicon film having deposited in 100% silane can be more easily crystallized as compared with a one having deposited in a hydrogen-diluted silane. The film deposition was conducted at a low temperature in this case to incorporate a large amount of hydrogen into the amorphous silicon film. In this manner, as many bondings as possible can be neutralized with hydrogen.
[0060] Furthermore, the input power of the high frequency wave energy (13.56 MHz) in this example was as low as 20 W. By thus lowering the input power, the formation of silicon clusters, i.e., partially crystalline portion, during the film deposition can be avoided. This condition was selected also based on the previous findings acquired through experiments. That is, the incorporation of a small crystalline portion into the amorphous silicon film unfavorably affects the later crystallization of the film which is conducted by irradiating a laser beam.
[0061] Then, a patterning was carried out to separate the films into devices to obtain a structure as shown in FIG. 1 . Subsequent to the patterning, the sample was heated in vacuum (of 10 −6 Torr or lower) at 450° C. for an hour to thoroughly drive out hydrogen therefrom to form dangling bonds in high density.
[0062] The sample thus obtained was transferred into a laser irradiation apparatus as shown in FIG. 5 , and was subjected to irradiation of an excimer laser beam. In this manner the sample was crystallized into polycrystalline silicon. In this step, a KrF excimer laser emitting a light at a wavelength of 248 nm was operated at a laser beam irradiating energy density of 350 mJ/cm 2 on a substrate heated to 400° C. The pulsed laser beam was applied from 1 to 10 shots per site.
[0063] After the laser irradiation step, the sample was cooled to 100° C. in a hydrogen atmosphere under a reduced pressure of about 1 Torr.
[0064] In the present example, the crystallization of the amorphous silicon film was performed by irradiating a laser beam thereon. Alternatively, a heating process may be used for the crystallization of an amorphous silicon semiconductor film provided on a glass substrate as well. A heating process in this case comprises heating the sample at a temperature not higher than the heat-resistant temperature of the glass, specifically, in a temperature range of from 450 to 700° C. (in general, at 600° C.) for 6 to 96 hours.
[0065] In FIG. 5 is shown an apparatus comprising a vacuum chamber 21 , a quartz (anhydrous quartz is preferred particularly in the case of excimer laser) window 22 through which a laser beam is irradiated to the sample from the outside of the vacuum chamber 21 , a laser beam 23 to irradiate the sample, a sample 24 , a sample holder 25 , a heater 26 for heating the sample, an evacuation system 27 , and an inlet system 28 for a gas of the starting material, an inert gas, and a carrier gas. A practical apparatus is generally equipped with a plurality of inlet systems, but in the figure is shown only one of those. In this example, a rotary pump and a turbo-molecular pump were connected to the evacuation system to achieve a lower vacuum and a higher vacuum, respectively. By appropriately using these two pumps, the concentration of the residual impurities (particularly oxygen) was reduced to a level as low as possible. The pumps to be used herein must be able to achieve a vacuum of 10 −6 Torr or lower, and preferably, a vacuum of 10 −8 Torr or lower.
[0066] After conducting the crystallization of the silicon film by operating an excimer laser in a vacuum chamber, a 100 nm thick SiO 2 film 14 as a gate insulator was deposited on the resulting structure by RF sputtering. Thus was obtained a structure shown in FIG. 2 . Then, a 150 nm thick amorphous silicon semiconductor layer or polycrystalline silicon semiconductor layer was deposited to give a gate electrode 15 on the gate insulating film 14 . This layer was deposited incorporating P (phosphorus) to render the layer N-conductive. A structure as shown in FIG. 3 was thus obtained by patterning out a gate region. The gate electrode may otherwise comprise a metal, such as aluminum, chromium, and tantalum. If aluminum or tantalum were to be used, the surface thereof should be anodically oxidized to prevent the gate electrode from suffering damage at the later step of laser irradiation. For a planar type TFT comprising an anodically oxidized gate electrode, reference should be made to Japanese patent application Hei-3-237100 or Hei-3-238713.
[0067] Then, to the structure as shown in FIG. 3 , impurities were doped using a laser beam again in an apparatus shown in FIG. 5 , in accordance with the process of the present invention. The sample placed inside the apparatus shown in FIG. 5 was heated under a PH 3 atmosphere, and a laser beam was irradiated thereto to carry out doping of P (phosphorus). Accordingly, the source and drain regions ( 131 and 133 in FIG. 4 ) were rendered N-conductive because the source and drain regions were doped with the impurity P (phosphorus). The channel-forming region ( 132 in FIG. 4 ), however, remained undoped because the gate insulator film 14 and the gate electrode 15 functioned as a mask to cut off laser beam irradiation. In FIG. 3 , the channel region is located between the source and drain regions under the gate electrode in the semiconductor 13 . The doping was carried out under conditions as follows.
Atmosphere 5% PH 3 (diluted with H 2 ) Sample temperature 350° C. Pressure 0.02-1.00 Torr Laser used KrF excimer laser (emitting light of 248 nm wavelength) Energy density 150-350 mJ/cm 2 Pulse repetition 10 shots
[0068] The source and drain regions can be activated simultaneously with the laser doping.
[0069] After establishing the source and drain regions above, a 100 nm thick SiO 2 film 16 was deposited as an insulator film by RF sputtering as shown in FIG. 4 . The film deposition conditions were the same as those employed in the film deposition of the gate insulator.
[0070] In the next step, contact holes were provided by patterning, and further, aluminum was vapor deposited to establish a source electrode 17 and a drain electrode 18 . The resulting structure was thermally annealed at 350° C. in hydrogen to finish it into an NTFT. A P-channel TFT (a “PTFT”, hereinafter) could be fabricated similarly by using B 2 H 6 in the place of PH 3 .
[0071] Furthermore, to assure the effect of the present invention, a sample was prepared without heating it during irradiating a laser beam thereto, at the same laser beam intensity as used in the process according to the present invention. The result is shown in FIG. 9 ( b ). It can be seen clearly from these curves that the impurity concentration of a sample fabricated without heating the sample remained more than an order of degree lower, and the impurities were confined to the vicinity of the surface. In contrast, the sample fabricated by heating it to 350° C. during the laser beam irradiation was found to contain the impurities at a high concentration and to have the impurities being diffused deep into the sample as shown in FIG. 9 ( a ).
[0072] As described in the foregoing, both an NTFT and a PTFT were fabricated according to the process of the present invention. These TFTs were further assembled into a CMOS inverter, which was found to have excellent characteristics as shown in FIG. 16 (upper). Furthermore, a plurality of these CMOS circuits were assembled into a ring oscillator, which was also found to yield excellent characteristics as shown in FIG. 16 (lower).
EXAMPLE 2
[0073] An NTFT established on a glass substrate was fabricated according to a doping process of the present invention. A glass substrate or a quartz substrate was used in this example as in Example 1. Then, an SiO 2 film or a silicon nitride film was first deposited on a glass substrate 11 to give a base protective film 12 as shown in FIG. 1 , following the same process described in Example 1.
[0074] Then, a 100 nm thick layer 13 of hydrogenated amorphous silicon semiconductor, which is intrinsic semiconductor or substantially intrinsic, was deposited on the SiO 2 film by plasma-assisted CVD process. A patterning process was then carried out to separate the film into devices to obtain a structure as shown in FIG. 1 . Subsequent to the patterning, the sample was heated in vacuum (of 10 −6 Torr or lower) at 450° C. for an hour to thoroughly drive out hydrogen therefrom to form dangling bonds in high density.
[0075] In the same chamber in which the process of driving out hydrogen was performed, the sample thus obtained was subjected to irradiation of an excimer laser beam while maintaining the vacuum. In this manner, the sample was crystallized into polycrystalline silicon under the same conditions as those used in the process of Example 1. After the laser irradiation, the sample was cooled to 100° C. in a hydrogen atmosphere under a reduced pressure of about 1 Torr.
[0076] In the present example, an apparatus as shown in FIG. 6 was used throughout the processes of heating the sample for removing hydrogen, crystallization of the sample by laser beam irradiation, and doping of impurities into the sample. Those processes were performed in the same single vacuum chamber. This is advantageous in that the sample can be easily maintained in high vacuum throughout the processes and that thereby the film can be maintained free from impurities (particularly oxygen). The vacuum chamber can be used as a plasma-assisted CVD apparatus, as is equipped with an electrode for applying an electromagnetic energy to the atmosphere. However, the processes above may be carried out separately in different reaction furnaces by using an apparatus having a multi-chamber arrangement. The reaction furnace in this example had a positive column structure, but the structure of the useful furnaces is not only limited thereto, and furnaces having other types of structures may be used as well. The manner of applying an electromagnetic energy also is not particularly limited. An ECR type apparatus may be used to achieve a further high activation ratio on the samples.
[0077] In FIG. 6 is shown an apparatus comprising a vacuum chamber 31 , a quartz window 32 through which a laser beam is irradiated to the sample from the outside of the vacuum chamber 31 , a laser beam 33 to irradiate the sample, a sample 34 , a sample holder 35 , a heater 36 for heating the sample, an evacuation system 37 , and an inlet system 38 for supplying a gas of the starting material, an inert gas, and a carrier gas. A practical apparatus is generally equipped with a plurality of inlet systems, but in the figure is shown only one of these. In this example, a rotary pump and a turbo-molecular pump were connected to the evacuation system to achieve a lower vacuum and a higher vacuum, respectively. An electromagnetic energy of 13.56 MHz which is generated by a high frequency wave generator 40 is supplied to the chamber by a pair of parallel planar electrodes 39 .
[0078] After conducting the crystallization of the silicon film by operating an excimer laser in a vacuum chamber as shown in FIG. 6 , a 100 nm thick SiO 2 film 14 as a gate insulator was deposited on the resulting structure by RF sputtering. Thus was obtained a structure shown in FIG. 2 . Then, a 150 nm thick amorphous silicon semiconductor layer or polycrystalline silicon semiconductor layer was deposited to give a gate electrode 15 . This layer was deposited incorporating P (phosphorus) to render the layer N-conductive. A structure as shown in FIG. 3 was thus obtained by patterning out a gate region.
[0079] Then, to the structure as shown in FIG. 3 , impurities were doped using a laser beam again in an apparatus shown in FIG. 6 , in accordance with the process of the present invention. The sample placed inside the apparatus shown in FIG. 6 was heated under a PH 3 atmosphere being decomposed by the applied electromagnetic energy, and a laser beam was irradiated thereto to dope the sample with P (phosphorus). Accordingly, the source and drain regions ( 131 and 133 in FIG. 4 ) were rendered N-conductive because P was doped. The channel-forming region ( 132 in FIG. 4 ), however, remained undoped because the gate insulator film 14 and the gate electrode 15 functioned as a mask to cut off laser beam irradiation. The doping was carried out under conditions as follows.
Atmosphere 5% PH 3 (diluted with H 2 ) Sample temperature 350° C. Pressure 0.02-1.00 Torr Input energy 50-200 W Laser used KrF excimer laser (emitting light of 248 nm wavelength) Energy density 150-350 mJ/cm 2 Pulse repetition 10 shots
[0080] After establishing the source and drain regions above, a 100 nm thick SiO 2 film 16 was deposited as an insulator film by RF sputtering. The film deposition conditions were the same as those employed in Example 1. In the next step, contact holes were provided by patterning, and further, aluminum was vapor deposited to establish a source electrode 17 and a drain electrode 18 . The resulting structure was thermally annealed at 350° C. in hydrogen to finish it into an NTFT.
[0081] A P-channel TFT (a “PTFT”, hereinafter) could be fabricated similarly by this doping process, except for using B 2 H 6 in the place of PH 3 . In conventional processes, the mixture of gases is decomposed heterogeneously upon irradiation of a laser beam at a single wavelength depending on the differing decomposition degree of each of the component gases. The conventional processes thus suffered problematic non-uniform doping. However, the process according to the present invention is free from being non-uniformly doped, because the doping gas in this process is decomposed not by the laser beam but by an additionally applied electromagnetic energy. Thus, uniform doping was achieved in both PTFT and NTFT without being influenced by the wavelength of the applied laser beam.
EXAMPLE 3
[0082] In FIG. 7 is shown a doping apparatus according to the present invention, which comprises a chamber 71 provided with an anhydrous quartz slit window 72 through which a laser beam shaped into a thin rectangular form is irradiated to the sample. This laser beam is shaped, for example, into a rectangle 10 mm by 300 mm in size. The position of the laser beam is fixed. To the chamber are further connected an evacuation system 77 and an inlet system 78 for supplying the reactive gas. In the inside of the chamber are provided a sample holder 75 on which a sample 74 is mounted, and an infrared-emitting lamp 76 as a heater is set under the sample holder. The sample holder is movable so that the sample may be moved in accordance with the laser shots.
[0083] An apparatus equipped with a mechanism for moving the sample therein requires much care in its temperature control, because the mechanism may suffer mal-alignment due to dimensional change thereof caused by the heat generated by the heater. Furthermore, the chamber is a subject of frequent and troublesome maintenance work because the mechanism for moving the sample generates much dust.
EXAMPLE 4
[0084] In FIG. 8 (A) is shown a doping apparatus according to the present invention, which comprises a chamber 81 provided with an anhydrous quartz window 82 sufficiently transparent to transmit a laser beam. Dissimilar to the window provided to the apparatus used in Example 3, it is a wide one which can cover the whole sample 84 . To the chamber are connected a vacuum evacuation system 87 and an inlet system 88 for supplying the reactive gas (a gas containing an impurity element). In the inside of the chamber are provided a sample holder 85 on which a sample 84 is mounted, and the sample holder is equipped with an internal heater which functions as a heating means of the sample. The sample holder is fixed to the chamber. To the lower portion of the chamber is provided a table 81 a for the chamber so that the whole chamber may be moved in accordance with the laser shots. The laser beam used in this Example was also shaped into a narrow rectangle as the one used in Example 3. For example, a laser beam shaped into a rectangle of 5 mm×100 mm in size was used. Similarly again to the laser beam used in Example 3, the position of the beam was fixed. The apparatus used in this Example is different from that of Example 3 in that it employs a mechanism to make the whole chamber movable. Thus, the inner of the chamber is free from those mechanical parts and hence generates no dust. By arranging the apparatus in this way, much effort for maintenance work can be saved. Furthermore, the transport mechanism is independent of the heat generated from the heater.
[0085] The apparatus in the present Example is advantageous not only in the points mentioned hereinbefore, but also in the points as follows. The apparatus used in Example 3 requires a long dead time, i.e., it took a long time to get the laser fired after once a sample was loaded into the vacuum chamber, because a sufficient vacuum degree should be attained by evacuation. In the apparatus of the present Example, a plurality of chambers (at least two chambers) as shown in FIG. 8 (A) are provided so that they may be rotated to perform sequentially the steps of charging the sample, evacuating the chamber to vacuum, irradiating a laser beam to the sample, and taking out the sample from the chamber. In this manner, dead time can be completely eliminated from the process. In FIG. 8 ( b ) is shown a system employing the arrangement mentioned above.
[0086] In this system, chambers 96 and 97 charged with non-treated samples are transferred during the evacuation step by a continuously moving transportation mechanism 98 to a table 99 equipped with a precision stage. The chamber 95 being mounted on the stage contains a sample therein, and a laser beam having generated by a laser device 91 operating in a pulsed mode and processed by pertinent optical devices 92 and 93 is irradiated to the sample. After the sample is subjected to the desired laser beam irradiation treatment by moving the stage and the chamber 95 synchronously with the laser irradiation, the chamber 94 is transferred to the next step again by a continuously moving transportation mechanism 100 . During this transportation step, the heater inside the chamber is turned off and the chamber is evacuated to get ready to take out the sample after it is sufficiently cooled.
[0087] As was described in the foregoing, the apparatus used in the present Example cuts off the waiting time for being evacuated, and hence the throughput can be increased. It should be noted, however, that this process provides an increased throughput, but it requires many chambers to be installed. Hence, the apparatus must be chosen by taking into consideration the scale of mass production and of cost.
EXAMPLE 5
[0088] An NTFT established on a glass substrate was fabricated according to a doping process of the present invention. A glass substrate or a quartz substrate was used in this example as in Example 1. Then, an SiO 2 film was first deposited on a glass substrate 101 to give a base protective film 102 as shown in FIG. 1 , following the same process described in Example 1. Then, a 100 nm thick layer 103 of hydrogenated amorphous silicon semiconductor, which is substantially intrinsic, was deposited on the SiO 2 film by plasma-assisted CVD process. A patterning process was then carried out to separate the film into devices to obtain a structure as shown in FIG. 1 . Subsequent to the patterning, the sample was heated in vacuum (of 10 −6 Torr or lower) at 450° C. for an hour to thoroughly drive out hydrogen therefrom to form dangling bonds in high density. A 100 nm thick SiO 2 film was then deposited on the resulting product by RF sputtering to obtain a structure shown in FIG. 10 (A). A silicon oxide mask 105 was left over only on channel portions.
[0089] Then, an impurity was doped in the sample according to a process of the present invention using a laser beam in an apparatus as shown in FIG. 6 . The sample as shown in FIG. 10 (B) was placed in the apparatus, and was heated under PH 3 atmosphere having decomposed by the applied electromagnetic energy. To the sample was then irradiated a laser beam to carry out the doping of P (phosphorus). Accordingly, the source and drain regions ( 106 and 108 in FIG. 10 (B)) were rendered N-conductive because P was doped. The channel-forming region ( 107 in the same figure), however, remained undoped because the silicon oxide mask 105 functions to cut off laser beam irradiation. Accordingly, this channel-forming region was crystallized but remained undoped. It can be seen that a crystallization step and a doping step using a laser beam was conducted at the same time. The doping was carried out under the same conditions as those used in Example 2.
[0090] After establishing the source and drain regions above, a gate oxide film 110 and a gate electrode 109 were deposited, and a 100 nm thick SiO 2 film 111 was further deposited thereon as an interlayer insulator. Further thereafter, contact holes were patterned, and aluminum was vapor deposited thereon to give a source electrode 112 and a drain electrode 113 . Thus was the structure finished into an NTFT as shown in FIG. 10 (C) by thermally annealing it in hydrogen at 350° C.
[0091] In the process described in the present Example, source and drain cannot be formed in a self-aligned manner. However, the crystallization of the channel region and the doping of the source and drain can be performed simultaneously as in the process of the present Example by, for instance, establishing first a gate electrode on the gate insulator film in the similar manner as in Example 1 and then irradiating a laser beam from the back of the gate insulator film.
EXAMPLE 6
[0092] An active matrix as shown in FIG. 11 was fabricated on a Coning 7059 glass substrate. The substrate 201 was a 1.1 mm thick Coning 7059 glass 300×400 mm×1.1 mm in size as shown in FIG. 11 (A). The substrate was coated with silicon nitride film 202 by plasma-assisted CVD to a thickness of from 5 to 50 nm, preferably, from 5 to 20 nm, so as to prevent the impurities such as sodium initially present in the substrate from being diffused into the TFT. For technologies forming a blocking layer by coating the substrate with silicon nitride or aluminum oxide, reference should be made to Japanese patent application Hei-3-238710 or Hei-3-238714, filed by the present inventors.
[0093] After then depositing a silicon oxide film as a base oxide film 203 , a silicon film 204 was deposited by a low-pressure CVD or plasma-assisted CVD process to a thickness of from 30 to 150 nm, preferably from 30 to 50 nm. A silicon oxide film was deposited further thereon as a gate insulator film 205 using tetraethoxysilane (TEOS) as the starting material, by a plasma-assisted CVD process in oxygen atmosphere to a thickness of from 70 to 120 nm, typically, to a thickness of 100 nm. The substrate was maintained throughout to a temperature of 400° C. or lower, preferably, in the temperature range of from 200 to 350° C. to prevent shrinking or warping from occurring on the glass substrate. However, in this temperature level, the oxide film suffered formation of a large number of recombination centers therein to give, for example, an interface level density of 10 12 cm −2 or higher. Thus, it was found unfeasible to use the oxide film as a gate insulator.
[0094] Accordingly, the structure was subjected to a KrF laser irradiation in a hydrogen-diluted phosphine (5% PH 3 ) atmosphere as shown in FIG. 11 (A) to have the crystallinity of the silicon film 204 improved and also to have the quantity of the recombination centers (trap centers) of the gate oxide film 205 reduced. The laser was operated at a beam energy density of from 200 to 300 mJ/cm 2 , and at a pulse repetition of 10 shots. Preferably, the temperature is maintained in the range of from 200 to 400° C., representatively, at 300° C. As a result, the silicon film 204 was improved in crystallinity, and the gate oxide film 205 was found to contain doped phosphorus at a density of from 1×10 20 to 3×10 20 cm −3 and to have a reduced interface level density of 10 11 cm −2 or lower.
[0095] Then, an aluminum gate electrode 206 was deposited on the resulting product to give a structure as shown in FIG. 11 (B), and the periphery thereof was further coated with an anodically oxidized product 207 .
[0096] Then, boron, an impurity for imparting P-conductivity, was implanted in a self-aligned manner into the silicon layer by an ion doping process to give a source and a drain 208 and 209 of the TFT, followed by the irradiation of a KrF laser to recover for the damage given to the silicon film during the ion doping. For this purpose, the laser beam was irradiated at a relatively high energy density of from 250 to 300 mJ/cm 2 . The resulting source and drain yielded a sheet resistance of from 300 to 800 Ω/cm 2 .
[0097] As shown in FIG. 11 (D), an interlayer insulator 210 was provided using polyimide, and a pixel electrode 211 was established thereon using ITO (indium-tin-oxide). Furthermore, as shown in FIG. 11 (E), contact holes were bore to provide chromium electrodes 212 and 213 on the source and drain regions of the TFT. One of the electrodes, the electrode 213 , was further connected to the ITO electrode. Thus, the structure was finished into a pixel for a liquid crystal display device by annealing the resulting product in hydrogen at 300° C. for 2 hours.
EXAMPLE 7
[0098] A TFT was fabricated by doping of phosphorus into a silicon oxide film to give a gate insulator film as in Example 6. Similar to the process employed in Example 6, a silicon nitride film 202 was deposited over the whole surface of a substrate 201 by plasma-assisted CVD, to a thickness of from 5 to 50 nm, preferably, from 5 to 20 nm. Then, after depositing a silicon oxide film as the base oxide film 203 , a silicon film 204 was deposited by a low-pressure CVD or plasma-assisted CVD process to a thickness of from 30 to 150 nm, preferably from 30 to 50 nm. A silicon oxide film was deposited further thereon as a gate insulator film 205 by sputtering to a thickness of from 70 to 120 nm, typically, to a thickness of 100 nm. Alternatively, this step may be performed using tetraethoxysilane (TEOS) as the starting material, by a plasma-assisted CVD process in oxygen atmosphere as in Example 6. The substrate was maintained throughout to a temperature of 400° C. or lower, preferably, in the temperature range of from 200 to 350° C. to prevent shrinking or warping from occurring on the glass substrate.
[0099] Then, the structure was subjected to a KrF laser irradiation in a hydrogen-diluted phosphine (5% PH 3 ) atmosphere as shown in FIG. 11 (A) to have the crystallinity of the silicon film 204 improved and also to have the quantity of the recombination centers (trap centers) of the gate oxide film 205 reduced. The laser was operated at a beam energy density of from 200 to 300 mJ/cm 2 , and at a pulse repetition of 10 shots. The substrate was maintained at room temperature during the process. Accordingly, the doped phosphorus was confined within a region at a depth from the surface of 70% or less of the total thickness of the layer.
[0100] An aluminum gate electrode 206 was then deposited on the resulting product to give a structure as shown in FIG. 11 (B), and the periphery thereof was further coated with an oxide 207 obtained by anodic oxidation. Upon completion of the anodic oxidation, a negative voltage was inversely applied to the resulting product. More specifically, a voltage in the range of from −100 to −200V was applied for a duration of from 0.1 to 5 hours. The substrate was maintained in the temperature range of, preferably, from 100 to 250° C., and representatively, at 150° C. By carrying out this process, the movable ions which were present in silicon oxide or in the interface between silicon oxide and silicon were attracted to the gate electrode A 1 , and were trapped in the midway by the region containing phosphorus at a high concentration. Assumably, these phosphorus-rich regions are present as phosphosilicate glass. For details on this technique comprising applying a negative voltage to the gate electrode during or after the anodic oxidation process, reference should be made to Hei-4-115503, filed by the present inventors on Apr. 7, 1992.
[0101] Then, phosphorus, an impurity for imparting N-conductivity, was implanted in a self-aligned manner into the silicon layer by a known ion doping process to give a source and a drain 208 and 209 of the TFT, followed by the irradiation of a KrF laser as in FIG. 11 (C), to recover for the damage given to the silicon film during the ion doping. As shown in FIG. 11 (D), an interlayer insulator 210 was provided using polyimide, and a pixel electrode 211 was established thereon using ITO (indium-tin-oxide). Furthermore, as shown in FIG. 11 (E), contact holes were bore to provide chromium electrodes 212 and 213 on the source and drain regions of the TFT. One of the electrodes, the electrode 213 , was further connected to the ITO electrode. Finally, a TFT was obtained after annealing the resulting product in hydrogen at 300° C. for 2 hours.
EXAMPLE 8
[0102] A MOS (metal-oxide semiconductor) capacitor was fabricated by using a gate oxide film having prepared by laser doping a silicon oxide film on a single crystal substrate with phosphorus. The C-V characteristic curve of this MOS capacitor was obtained.
[0103] A silicon oxide film was deposited as a gate insulator film on a (100) plane of single crystal silicon, to a thickness of from 70 to 120 nm, typically to a thickness of 100 nm, by plasma-assisted CVD using tetraethoxysilane (TEOS) as a starting material in an oxygen atmosphere. The substrate was maintained at a temperature of 400° C. or lower, preferably, in the temperature range of from 200 to 350° C. However, in this temperature level, the oxide film was found to contain a large number of clusters containing carbon, and it also suffered formation of a considerable number of recombination centers to give, for example, an interface level density of 10 12 cm −2 or higher. Thus, it was found unfeasible to use the oxide film as a gate insulator.
[0104] Accordingly, the structure was subjected to a KrF laser irradiation in a hydrogen-diluted phosphine (5% PH 3 ) atmosphere in the same apparatus as used in FIG. 1 to have the quantity of the recombination centers (trap centers) of the silicon oxide film reduced. The laser was operated at a beam energy density of from 200 to 300 mJ/cm 2 , and at a pulse repetition of 10 shots. Preferably, the temperature is maintained in the range of from 200 to 400° C., representatively, at 300° C. As a result, the oxide film was found to contain doped phosphorus at a density of from 1×10 20 to 3×10 20 cm −3 and to have a reduced interface level density of 10 11 cm −2 or lower. Then, an aluminum gate electrode was deposited thereon.
[0105] A MOS capacitor fabricated without performing the laser, doping process yields, for example, a C-V curve having a large hysteresis as shown in FIG. 12 (A). In the figure, the abscissa is the voltage and the ordinate is the electrostatic capacity. A MOS capacitor subjected to a laser doping treatment according to the present invention yields a favorable C-V curve as shown in FIG. 12 (B), which is in sharp contrast with the C-V curve of FIG. 12 (A).
[0106] The film thus obtained by the process according to the present invention contains each of the elements distributed in the film in a manner as shown in FIG. 12 (C). It can be seen that the silicon oxide film having subjected to laser doping according to the present invention is doped with phosphorus to about a half of the total depth of the film, and that gettering was effected on sodium atoms thereby. It can be seen also that little or no carbon is present over the whole oxide film. This is because carbon was driven out from the film by laser irradiation. It is further effective to apply a negative voltage to the aluminum gate electrode as in Example 7, because the movable ions such as sodium ions present in the film can be attracted to the phosphorus-rich regions.
EXAMPLE 9
[0107] A 500 nm thick amorphous silicon film provided on a glass substrate was doped with an impurity by a process according to the present invention, and the film characteristics thereof were obtained. The results are given in FIGS. 13 to 15 . The laser used in this Example was a KrF laser emitting a beam at a wavelength of 248 nm. The chamber used in the present process was like the one shown in FIG. 5 . It was attempted in this Example to change the doped impurity by introducing different types of gases into the chamber. More specifically, a hydrogen gas containing 5% phosphine was supplied to the chamber during the laser irradiation to add an impurity which imparts N-conductivity to the semiconductor, and a hydrogen gas containing 5% diborane was introduced to the chamber during the laser irradiation to render the semiconductor P-conductive by doping of the impurity.
[0108] The chamber was maintained at a pressure of 100 Pa. The laser was irradiated at an energy density of from 190 to 340 mJ/cm 2 , and the pulse was provided at a repetition of from 1 to 100 shots. The temperature of the substrate was maintained at room temperature (R.T.) or at 300° C.
[0109] In FIGS. 13 and 14 are shown the change in diffusion of the impurities with varying substrate temperatures. In this case, the laser was operated at an energy density of 300 mJ/cm 2 and at a pulse repetition of 50 shots. FIG. 13 was obtained from the data collected by secondary ion mass spectroscopy (SIMS), and it shows how boron diffuses along the depth direction. As is clearly read from this figure, the impurity concentration was an order of magnitude higher for the sample provided at a substrate temperature of 300° C., as compared with that of a sample maintained at a substrate temperature of R.T.; also, the diffusion depth for the former was about twice as large as that of the latter.
[0110] In FIG. 14 is shown the distribution of phosphorus along the depth direction of the sample. A similar tendency as in the case of the distribution of boron was observed. The effect of heating the substrate was particularly prominent in the case of adding phosphorus.
[0111] In FIG. 15 are plotted the sheet resistances with varying laser energy density and number of shots. Boron was doped as the impurity. As the figure clearly reads, the sheet resistance decreases and the impurity concentration increases with increasing energy density. However, the sheet resistance seems to converge on a constant value.
[0112] Furthermore, despite the sheet resistance was observed to decrease with increasing number of shots, no considerable decrease in sheet resistance was observed at a laser, energy density of 220 mJ/cm 2 or higher in both cases of 50 shots and 100 shots. However, there was observed a great difference between the sheet resistances obtained for 1 shot and 5 shots. Accordingly, it was confirmed that the laser pulses at least 5 shots are necessary to achieve a stable laser irradiation.
[0113] As described in the foregoing, a semiconductor can be efficiently doped with an impurity which imparts either an N-conductivity or P-conductivity to the doped product by the process according to the present invention, said process comprising irradiating a laser beam to the semiconductor in an atmosphere containing the impurity above while heating the sample or while applying an electromagnetic energy to a reactive gas to decompose it into an atmosphere containing the impurity above. In particular, the process according to the present invention is effective in that the doping can be conducted without damaging the glass substrate, yet without being influenced by the wavelength of the laser used and by the type of the doping gas used in the process.
[0114] Furthermore, as mentioned earlier, the present invention is industrially valuable because it not only is confined to the field of doping semiconductors with impurities, but also is applicable to a variety of fields, such as the surface modification of metal and ceramic materials and the addition of trace elements into thin films of metal, ceramics, and insulators.
[0115] While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.
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A process for laser processing an article, which comprises: heating the intended article to be doped with an impurity to a temperature not higher than the melting point thereof, said article being made from a material selected from a semiconductor, a metal, an insulator, and a combination thereof; and irradiating a laser beam to the article in a reactive gas atmosphere containing said impurity, thereby allowing the impurity to physically or chemically diffuse into, combine with, or intrude into said article. The present invention also provides an apparatus for use in a laser processing process, characterized by that it is provided with an internal sample holder and a device which functions as a heating means of the sample, a window made of a material sufficiently transparent to transmit a laser beam, a chamber comprising a vacuum evacuation device and a device for introducing a reactive gas containing an impurity element, a laser apparatus operating in a pulsed mode to irradiate a laser beam to said chamber, and a means to move said chamber synchronously with the laser irradiation.
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TECHNICAL FIELD
[0001] The present description relates, in general, to baluns and, more specifically, to Marchand baluns utilizing asymmetric coplanar striplines.
BACKGROUND
[0002] Antennas are typically of two types, namely symmetrical or balanced, and asymmetrical or unbalanced. FIG. 1 depicts a typical unbalanced antenna 100 . The antenna 100 includes monopole 101 and ground 102 . The input or feed structure is also unbalanced, and may be a coaxial cable 104 with ground shielding 103 or a micro-stripline (not shown). The unbalanced antenna has a single element for the total energy of the signal, which alternates + (positive) and − (negative). Note that the ground plane functions as part of the antenna, and thus strongly affects the performance of the antenna. The antenna can be detuned if the size of the ground place is between 0.25 and 2 wavelengths of the antenna resonant frequency. Other elements connected to the ground plane can also detune the antenna. Since antenna resonant frequency and performance depends on the shape of the device, each antenna needs to be customized, leading to higher design and production costs. However, since there are multiple radiating elements, the antenna 100 is useful for multi-band applications, e.g. mobile phones. However, if the RF module that provides the signal to the antenna 100 is balanced, an additional balun type antenna is required, which introduces additional losses and decreases the antenna's radiation performance. Examples of antenna 100 are monopole, patch, and PIFA (planar inverted-F antenna).
[0003] FIG. 2 depicts a typical balanced antenna 200 . The antenna 200 includes loop 201 with ground 204 . The input or feed structure is also balanced, and comprises separate + input 202 and − input 203 for each part of the alternating signal. The feed structure may comprise a coplanar microstrip line or two-wire transmission line. Note that with this arrangement, the ground plane is essentially independent from the antenna and has little effect on the performance of the antenna. Thus, the antenna resonant frequency and performance depends on the shape of the device, and a single antenna can work with a variety of ground plane geometries. However, since this arrangement has a symmetric geometry, the size of the antenna is double that of an equivalent unbalanced antenna. This antenna has a single radiating element and can be configured to operate in wide-band single resonance applications, such a magnetic resonance imaging (MRI) device and other inductive coupling applications.
[0004] In designing electronic circuits, e.g. mixers or amplifiers, balun antennas are used to link a symmetrical or balanced circuit with an asymmetrical or unbalanced circuit. Thus, a balun can be used to change an unbalanced signal to a balanced signal in order to drive a balanced antenna element, or vice versa. FIG. 3 depicts a typical Marchand type balun antenna 300 . The Marchand balun has an unbalanced input 303 and a balanced output 301 . The input goes to two coupled line sections 304 , 305 , the lengths of which are λ/4 (a quarter wavelength) of the input signal. The portions of the line sections that are connected to the outputs are shorted to ground. The portions of the line sections that are connected to the input are connected to an open circuit (OC). The Marchand balun operates through the coupling that occurs between the lines. The balun offers good amplitude balance and phase difference with a relatively wide operating bandwidth.
[0005] Note that in the balun of FIG. 3 , the operating bandwidth is mainly controlled by the coupling strength of the two coupled-line sections. There are two types of coupled-lines, namely edge coupled and coplanar coupled. FIGS. 4A and 4B depict examples of edge coupled lines 401 , and coplanar coupled lines 402 , respectively. In FIG. 4A , the signal line 403 couples with line 406 . The couple lines are separated from a ground place 404 by dielectric material 405 . This coupling is referred to an edge coupling. With this arrangement, manufacturing capability limits the coupling strength between a pair microstrips. In FIG. 4B , the signal line 403 couples with line 406 . The couple lines are separated by dielectric material 405 . Ground plane 404 are adjacent to the couple lines. This arrangement is referred to as a coplanar waveguide configuration or broadside configuration, where one coplanar waveguide (e.g. 403 ) is on the top of the dielectric 405 and another coplanar waveguide (e.g. 406 ) is on the bottom of the dielectric. Strong coupling can be achieved by a pair lines in this arrangement.
[0006] There are two types of coplanar coupling, namely symmetrical and asymmetrical. FIGS. 5A and 5B depict examples of symmetrical 501 and asymmetrical 502 coplanar coupled lines, respectively. In FIG. 5A , the signal line 503 is coplanar with line 504 and separated by dielectric layer 508 . The ground planes 505 and 506 are also coplanar and separated by dielectric layer 508 . In FIG. 5B , the signal line 503 is coplanar with line 504 and separated by dielectric layer 508 . However, the ground planes 505 and 507 are not arranged in the same manner as the signal lines. This arrangement is referred to as asymmetric coplanar striplines (ACPS), and can be used to reduce the space for grounding, while still achieving strong coupling. The ACPS striplines will also have a wide bandwidth as the symmetrical coplanar striplines of FIG. 5A . A Marchand balun based on ACPS coupling has a small size and a wide operating bandwidth.
[0007] Inhomogeneous media can cause a large difference between the even-mode and odd-mode velocities. A large difference degrades the performance of the balun. An arrangement that has a nonuniform ACPS that is covered with a dielectric can be used to overcome this problem. FIGS. 6A and 6B depict different views of a nonuniform ACPS coupler 600 . In this arrangement, the ground place is formed into an irregular shape. This arrangement improves performance of the bandwidth, because it reduces the difference in the even and odd mode velocities through the waveguides.
BRIEF SUMMARY OF THE INVENTION
[0008] Various embodiments of the invention are directed to a nonuniform, asymmetric coplanar stripline Marchand balun and methods for use of such a balun. A balun formed according to embodiments of the invention can have an unbalanced input and a balanced output, or vice versa. Such a balun can be used to feed a balanced antenna from an unbalanced signal feed, or vice versa.
[0009] One embodiment of the invention is to use ACPS to form a Marchand balun with strong coupling, and thus achieving a balun with wideband characteristic and small in size. The wideband balun is easier to fabricate and small in size for ultrawide bandwidth (UWB) applications. The UWB balun may be formed from one or two PCB layers having two layers of conductors. It is preferable to use a single PCB layer. In contrast, a prior art UWB balun tends to be very complicated and require three or more PCB layers, and thus is large in size.
[0010] Another embodiment of the invention is to form a balun using an open-circuit stub to introduce a rejection at the middle of the operating band to make a dualband balun. This embodiment simplifies the design of dualband wireless frontend systems.
[0011] Embodiments of the invention can be used to drive balanced antenna elements in a variety of applications. For example, one or more embodiments can be used to drive balanced antennas in an MRI system. Typical MRI systems use loop antennas to generate a large amount of magnetic field, and the loop antennas can be fed by baluns according to embodiments of the present invention. Further, various embodiments can be used in near-field applications, such as radio frequency identification (RFID). Other applications include the use in single layer superconducting elements.
[0012] The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawing, in which:
[0014] FIG. 1 depicts a typical unbalanced antenna;
[0015] FIG. 2 depicts a typical balanced antenna;
[0016] FIG. 3 depicts a typical Marchand type balun antenna;
[0017] FIGS. 4A and 4B depict examples of edge coupled lines and coplanar coupled lines, respectively;
[0018] FIGS. 5A and 5B depict examples of symmetrical and asymmetrical coplanar coupled lines, respectively;
[0019] FIGS. 6A and 6B depict different views of a nonuniform ACPS coupler;
[0020] FIGS. 7A and 7B depict an example of a system using embodiments of the invention and a conventional system, respectively;
[0021] FIGS. 8A , 8 B, and 8 C depict different views of an ACPS UBW balun, according to embodiments of the invention;
[0022] FIGS. 9A and 9B depict performance graphs of the balun of FIGS. 8A-8C ;
[0023] FIG. 10 depicts a schematic diagram of a dual band balun, according to embodiments of the invention;
[0024] FIGS. 11A , 11 B, and 11 C depict different views of an example of a dual band balun of FIG. 10 , according to embodiments of the invention;
[0025] FIG. 12 depicts a performance graph of an example of the balun of FIGS. 11A-11C ; and
[0026] FIG. 13 depicts a performance graph of another example of the balun of FIGS. 11A-11C .
DETAILED DESCRIPTION OF THE INVENTION
[0027] Embodiments of the invention use asymmetric coplanar striplines (ACPS) to form a Marchand balun with strong coupling, and thus achieving a balun with wideband characteristic and small in size. Embodiments use an open-circuit stub to introduce a rejection at the middle of the operating band to make a dualband balun. The dualband balun simplifies the design of dualband wireless frontend systems. Embodiments of the invention can form a wideband balun that is small in size for ultrawide bandwidth (UWB) applications.
[0028] FIG. 7A depicts an example of a system using a dual band balun, according to embodiments of the invention. In this arrangement, system 700 transmits and receives at two frequencies. System 700 includes a dual band balun 701 for coupling the balanced inputs 702 to an unbalanced antenna 703 . A diplexer 704 is used to switch merge/split the different signals. A dual band pass filter 705 is used to condition the signals. In contrast, a convention system 750 , shown in FIG. 7B needs two baluns 751 , 752 , one for each frequency, along with two band pass filters 753 , 754 .
[0029] FIGS. 8A , 8 B, and 8 C depicts different views of an ACPS UBW balun, according to embodiments of the invention. FIG. 8A depicts a perspective view of the balun 800 . FIG. 8B depicts a top-down view of the upper layer 801 of balun 800 , and FIG. 8C depicts a top-down view of the bottom layer 802 of balun 800 . Note that the upper and lower layers are by way of example only, as they could be reversed. The balun 800 comprises balanced ports 803 , 804 and an unbalanced port 805 . The other ends of lines (i.e. connecting to ports 803 and 804 ) are shorted to ground 806 through the lines with the length ∫ approximately λg/4, λg being the wavelength of operating frequency. In addition, the lines with the length of ∫ on the top layer overlap the line connected to the port 805 on the bottom layer. The balun is formed from two nonuniform ACPS couple lines on two sides of a single layer of a printed circuit board (PCB). The upper layer 801 comprises the balanced ports 803 , 804 with lines connected to the ground plane (conductor) 806 . Area 807 comprises dielectric material. The ground plane 806 includes wedge portion 810 , which forms a nonuniform ACPS and improves the bandwidth. The dimensions of wedge portion 180 may be adjusted to improve the balun performance for particular frequencies. The bottom layer 802 comprises the unbalanced port 805 and ground plane (conductor) 808 . A portion of the line connected to the port 805 overlap the lines (i.e. connecting to ports 803 and 804 ) on the top layer with a resonator length ∫. Area 809 comprises dielectric material. Vias 811 connect ground planes 806 and 808 .
[0030] FIGS. 9A and 9B depict performance graphs of the balun of FIGS. 8A-8C . The balun of FIGS. 8A-8C , each of the ports 803 , 804 , and 805 are coupled to 50 Ohm resistors. FIG. 9A depicts the loss of the balun over frequency. Curve 902 depicts the reflection or return loss of the port 805 , and curves 903 , 904 depict the transmission or insertion loss between the port 805 and the ports 803 , 804 . Note that the amplitude balance is within ±0.5 dB over 32-50 MHz. Also note that the return loss is less than −10 dB in the working band. The dip in curve 902 indicates low reflection in the working band. The relatively flat and constant nature of curves 903 and 904 indicate good transmission throughout the working band. FIG. 9B depicts the phase effects of the balun over frequency. Curve 905 depicts the phase at port 805 , and curve 906 depicts the phase at port 804 . The phase at port 803 would be similar that of port 804 . Note that the phase difference is within ±50 over 30 MHz to 50 MGHz. Thus, as indicated by the performance in the 30 MHz to 50 MHz range, balun 800 is suitable for use in MRI systems or other RF circuits which need the conversion between balanced ports and unbalanced ports.
[0031] FIG. 10 depicts a schematic diagram of a dual-band balun 1000 , according to embodiments of the invention. The dual-band balun 1000 is a Marchand type balun antenna. The balun has an unbalanced port 1003 and a pair of balanced ports 1001 , 1002 . The balun includes two coupled line sections 1004 , 1005 , the length of which is around λ/4 (a quarter wavelength) of the operating frequency. The portions of the line sections that are connected to the balanced ports are shorted to ground. The portions of the line sections that are connected to the unbalanced port are connected to an open circuit (OC) through stub portion 1006 . The stub portion 1006 may be around a quarter wavelength long (a quarter wavelength of the operating frequency). The stub portion 1006 may be implemented by a meandering microstrip to reduce the overall size. This balun has a wide operating bandwidth and introduces a strong rejection at the band center and improves return loss at two separate frequencies.
[0032] FIGS. 11A , 11 B, and 11 C depicts different views of an example of a dual band balun of FIG. 10 , according to embodiments of the invention. FIG. 11A depicts a perspective view of the balun 1100 . FIG. 11B depicts a top-down view of the upper layer of balun 1100 , and FIG. 11C depicts a top-down view of the bottom layer of balun 1100 . Note that the upper and lower layers are by way of example only, as they could be reversed. The balun 1100 comprises balanced ports 1101 , 1102 and an unbalanced port 1103 . The two coupling areas, which is the overlap between unbalanced port 1103 and balanced ports 1101 , 1102 are shown as 1104 and 1105 . The balun is formed from two nonuniform ACPS couple lines on two sides of a single layer of PCB. The upper layer comprises the unbalanced port 1103 and ground plane (conductor) 1107 . Area 1108 comprises dielectric material. The upper layer also includes stub portion 1106 . Note that in this example, the stub portion in meandered to reduce the footprint of the stub portion. Note that the meandering is by way of example only as other meander patterns may be used or no meandering may be used. The lower layer comprises the balanced ports 1101 and 1102 and ground place (conductor) 1109 . Area 1110 comprises a dielectric material. Vias 1111 connect ground planes 1107 and 1109 .
[0033] FIG. 12 depicts a performance graph of an example of a balun of FIGS. 11A-11C . In this example, each of the ports 1101 , 1102 , and 1103 are coupled to 50 Ohm loads. FIG. 13 depicts the performance of balun over frequency. Curve 1201 depicts the reflection or return loss of the unbalanced port ( 1103 ), and curve 1202 depicts the transmission or insertion loss between unbalanced port ( 1103 ) and unbalanced ports ( 1101 , 1102 ). The location off f 0 , f 1 and f 2 are determined by the stub length. The f 1 and f 2 also depend on the coupling strength of the balun. The return loss can also be adjusted by the stub impedance. The frequencies f 1 and f 2 are lower and upper working bands, respectively. The dips of the blue curve show that the balun has two distinct operating bands. The red curve shows good transmission performance in the working bands. The quarter-wavelength stub corresponds to f 0 .
[0034] FIG. 13 depicts a performance graph of another example of a balun of FIGS. 11A-11C . In this example, the balanced port (i.e. 1101 , 1102 ) is coupled to 100 Ohm resistors, and port 1103 is coupled to a 50 resistor. The stub length is around quarter wavelength at 400 MHz. The balun in this system is used for dual bands which are 200 MHz and 500 MHz bands. FIG. 13 depicts the performance of balun over frequency. Curve 1301 depicts the reflection or return loss of the unbalanced port 1103 . The locations of f 1 and f 2 are determined by the length of the stub and coupling strength of the balun. The return loss can also be adjusted by the stub impedance. The frequencies f 1 and f 2 are lower and upper working bands, respectively. The dips of the blue curve show that the balun has two distinct operating bands. Note that there is more than 15 dB return loss at the 200 MHz band, and more than 15 dB return loss at the 500 MHz band.
[0035] It should be noted that while the examples of FIGS. 9A , 9 B, 12 , and 13 show performance in specific frequency bands, the scope of embodiments is not so limited. In fact, embodiments can be designed to operate at any radio frequency (RF) band through scaling and shaping. Further, the specific shapes and designs shown herein are exemplary, as other embodiments can take different shapes and/or designs. Moreover, some embodiments of the invention include methods for use of baluns designed according to the concepts described herein.
[0036] Some embodiments can be deployed in MRI systems to feed balanced antenna elements. Additionally, some embodiments can be used in Near Field Coupling (NFC) applications, such as RFID. Other uses are also possible, such as, e.g., in handheld consumer devices.
[0037] Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.
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A balun comprises at least two asymmetric coplanar striplines, a first of the striplines coupled to a signal input, and a second of the striplines coupled to a signal output, the at least two asymmetric coplanar striplines configured in a Marchand architecture to receive an unbalanced signal and to output a balanced signal.
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BACKGROUND OF THE INVENTION
[0001] This invention discloses a fiber with ultraviolet covering effect use to manufacture textiles. Specifically, this invention discloses fibers, having ultraviolet covering effect use to manufacture textiles, whose filaments are formed by adding inorganic titanium dioxide particles preferably below 1% weight of the total fiber composition. The inorganic titanium dioxide particles have dimensions of preferably less than 100 nm.
[0002] Due to large increase in outdoor activities, the market demand for textiles with ultraviolet covering effect use to produce of various types of sportswear, including sportswear for fishing and golfing have largely increased. Demand for household textiles with ultraviolet covering effect, such as garment, hat gingham and curtains, etc. have also largely increased. Conventional attempts to develop and improve fibers use to manufacture textiles with ultraviolet covering effects have been to increase fiber density or add fluorescent or whiting agents to the fiber filaments. However, increasing fiber density causes poor air permeability and is not suitable for summer textiles, although a higher degree of ultraviolet covering effect protection is needed. The use of fluorescent or whiting agents poses numerous problems. As an example, textiles with fluorescent or whiting agents have demonstrated poor reflection efficiency for ultraviolet rays.
[0003] Other technologies have used ultraviolet reflection agents or/and ultraviolet absorbent agents to insert ultraviolet covering effect protection in textile producing fibers. An ultraviolet reflection agent or ultraviolet absorbent agent can be an inorganic or an organic compound. Because the physical properties of fibers are easily and negatively influenced by the use of organic compound as agents, inorganic compounds are more frequently used. Examples of inorganic ultraviolet reflection and absorbent agents are Titanium Dioxide, Talcum, Kaolin, Zinc Oxide and Ferric Oxide. Titanium Dioxide, which possesses optimal ultraviolet reflection on visible light is frequently used. Similarly, organic compounds with ultraviolet reflection effect on visible light, such as salicylic acid, benzophenone, benzotriazole, cyanoacrylate are often use as ultraviolet absorbent agents.
[0004] Ultraviolet reflection agents and ultraviolet absorbent agents can be directly added to the fibers during the fibers' spinning process, or alternatively directly onto the textile produced from the fiber during post process coating. Adding ultraviolet reflection and/or absorbent agents onto the textile surfaces during post process coating reduces the air permeability of the textile by clogging the textile aperture. Other draw backs associated with using post process coating are that the produced textiles are usually warmer, that is, textiles absorb and accumulate more heat when worn, and the absorbent and/or reflection agents are quickly shed after numerous washing, reducing the ultraviolet covering effect. Therefore, the addition of ultraviolet agents, via post process coating is not strongly recommended.
[0005] Many attempts have been made to develop and improve the covering effect of ultraviolet light in fibers and fabrics produced from said fibers. Japanese Patent Application Laid-Opened No. 5-148734, discloses a fiber structure having ventilation degree exceeding 5 ml/cm 2 , which contains ultraviolet reflection or absorbent agent with the following results: the ultraviolet penetration of wavelengths between 290-320 nm is below 5%; the ultraviolet penetration of wavelengths between 290-400 nm is below 10%; and the visible light reflectivity of wavelengths between 400-1200 nm is above 60%. Japanese Patent Application Laid-Open No. 5-93343, discloses a core sheath constructing fiber with ultraviolet covering effect containing metal oxide of between 5-40 weight % of the fiber. The Application discloses tatting fabric having covering factor of between 700-1300 nm, knitted fabric having covering factor between 200-500 nm, and an ultraviolet passing percentage of the core cloth produced from the core sheath constructing fiber below 10%. Japanese Patent Application Laid-Open No. 5-186942 discloses a knitted fabric with double-layer construction having surface layer hydrophobic fiber of titter above 1 denier per filament. The lining and contact layers are made with fiber comprising protective inorganic compounds constituting over 3% weight of the layers, which protects against reflective visible light and near infrared ray light sources.
[0006] The three patent applications discussed above disclose technologies for improving fiber ultraviolet covering features by adding metallic compounds constituting between 1% and 40% weight of the fiber and with ultraviolet reflection or absorbent characteristics. Adding large quantities of metallic compounds into a textile producing fibers, as proposed by the Japanese Laid-Opened patent applications, reduce spinning productivity and fiber strength and result in the formation of tinct yellow fibers. Besides having metallic compounds expressed uncontrollably on the fibers surfaces, using large quantities of metallic compounds will affect thread routing machines doing the weaving and finishing stages of the fiber/textile manufacturing process. In essence, using large quantities of metallic compounds will greatly reduce the life span of the fibers produced, and increase manufacturing cost.
[0007] To resolve some of the problems associated with the Japanese laid-open patent applications and other problems associated with traditional methods for creating ultraviolet covering effect in fibers, the inventor discovered that by adding inorganic titanium metal particles having average particle diameter preferably less than 100 nm and potassium tripolyphosphate into textile producing fibers, results in the following: (1) increased the distribution area of the fibers; (2) avoided the cohesion phenomena associated with using titanium dioxide metal particle alone; (3) increased distinctly the ultraviolet reflection effect; (4) improved spinning productivity; (5) improved fiber stress; (6) improved fiber tinct; (6) improved fiber abradability; and (7) protected processing machines during threading and weaving of the fabric.
[0008] Consequently, it is an object of this invention to manufacture fibers, use in textile production, with ultraviolet covering effect, which contains less than 1% weight of inorganic titanium particles with average particle diameter size of preferably less than 100 nm.
[0009] Another object of this invention is to produce fibers having ultraviolet covering effect, which weighs preferably over 50% of fabric produced from said fibers
[0010] Still another object of this invention is to produce fabrics, using the fiber of this invention, having opening or permeability rate exceeding preferably 0.7%, but preferably less than 25%, and having an ultraviolet protection factor of preferably over 40%.
[0011] Finally, it is still an object of this invention to produce fibers, use for producing textiles, having ultraviolet covering protection containing preferably less than 1% weight of inorganic titanium dioxide particles mixed with potassium tripolyphosphate to prevent coagulation of the titanium dioxide metal particles.
SUMMARY OF THE INVENTION
[0012] This invention relates to a type of fiber having ultraviolet covering effect use to manufacture textiles for clothings and for producing household textiles, such as garment hat gingham and curtains, etc. The ultraviolet covering effect results from inventing a fiber containing preferably less than 1% weight of inorganic titanium particles having average diameter preferably less than 100 nm.
[0013] When used to manufacture textiles, the fiber of this invention constitutes preferably over 50% weight of textiles, produces textiles having permeability rate preferably exceeding 0.7% but preferably less than 25% and produces textiles having ultraviolet protection factor of preferably over 40%. Finally, the fiber of this invention with ultraviolet covering protection contains preferably less than 1% un coagulated titanium dioxide metal particles obtained by mixing the inorganic titanium particles with potassium tripolyphosphate.
DETAILED DESCRIPTION OF THE INVENTION
[0014] To obtain fibers having ultraviolet covering effect use for manufacturing textiles, this invention advances its proven concept of adding to the fibers' composition inorganic titanium dioxide metal particles having average dimensions of about 100 mn. The addition of titanium dioxide enhances resistant to ultraviolet light while increasing the overall surface area of the fibers thereby increasing permeability or opening rate of textiles manufactured from said fiber filaments.
[0015] Other advantages of having inorganic titanium metal particles are reduction in feed rate during production due to increase fiber surface area, reduction in overall manufacturing cost as feed rate is increased, improved spinning productivity, enhanced fiber strength, enhanced fiber tinct, improved abradability and improved threading and routing processes. The criticality of adding titanium dioxide particles constituting preferably below 1% weight of a total fiber is immense. Having fibers with titanium dioxide particles of weight percentage above 1 would most certainly result in the loss of or drastic reduction in the ultraviolet covering effect in textiles after repeated washing.
[0016] The manner in which the titanium dioxide particles are added to the fibers affects their ability to maintain its ultraviolet covering effect and may affect the overall quality of textiles manufacture from said fiber filaments. To avoid phenomenon such as the wash effect—removal of the ultraviolet covering effect due to repeated washing—the preferred method of adding the titanium dioxide to the fibers is directly, rather than post process coating. Direct addition of the titanium dioxide particles can occur at the polymerization stage of the fiber production process or the spinning stage with essentially identical results. However, whether the metal particles are added during the polymerization process stage or the spinning process stage avoiding coagulation of the titanium dioxide particles is paramount. The presence of coagulated titanium particles doing processing will most certainly impact the spinning productivity and will most certainly reduce the distribution area of the metal particles in the fibers thereby reducing the overall ultraviolet covering effect. Therefore, to prevent coagulation of the titanium dioxide metal particles, a dispersant such as potassium tripolyphosphate is added to the titanium particles by preparing a titanium dioxide/potassium tripolyphosphate sub-solution.
[0017] It is well known in the art that ultraviolet covering effect is influenced by the textile composition and the thickness of the textile. Tightly woven textiles have lower air permeability or opening rate. The thicker the texture, the better the ultraviolet covering effect. Because fabrics with ultraviolet covering effect are mostly desired and used during the summer season, the degree of textile permeability and thickness will greatly influence the degree of textile comfort when worn. To increase the comfort level of fabrics with ultraviolet covering effect, a cross model Y, W allotype sectional spinneret can be used during the spinning stage of the fiber production. The guiding gutter and the large surface area of the allotype section fiber can be utilized to make fabric having ultraviolet covering effect and fabric with the ability to absorb moisture while providing enhanced perspiration. Such fabrics will be suitable especially for summer activities.
[0018] Because Ultraviolet Protective Factor (UPF) determines the degree of ultraviolet covering effect in textiles, this invention looks to the AS/NZS 4399, 1996 Sun Protective Clothing Evaluation and Classification Standard for guidance. The Ultraviolet Protective Factor value and ultraviolet covering effect in AS/NZS 4399,1996 Sun Protective Clothing Evaluation Classification Standard revealed the following results: when UPF is between 25-39, the ultraviolet covering effect is considered very good; and when UPF is between 40-50 or above 50, the ultraviolet covering effect is considered excellent. The following methods for measuring ultraviolet protective factor, textile opening rate and yarn abradability were partly used to assess the reliability of the inventive findings:
[0019] 1. LUPF value menstruation:
[0020] Measured with AS/NZS 4399:1996 standard.
[0021] 2. Textile opening rate menstruation:
[0022] The measurement of the opening rate using a light microscopic having magnification between 10-15 comprised the following steps: placing a light source inside the textile to be measured to make the textile transparent; taking a microscopic photograph of the transparent textile; and calculating the percentage of the total area of the white section with respect to the total area of the textile—the percentage of the white section is the opening rate of the textile.
[0023] 3. Yarn abradability menstruation:
[0024] The measurement of the yarn abradability comprised the following steps: Grinding the yarn to be measured with copper wire having dimensions of 0.25 mm linear diameter, under a tension of 0.5 gm/denier, and at a rate of 300 m/minutes; and recording the passing length of the yarn when the copper wire is grinded and ruptured by the yarn. The longer it takes the yarn to pass through, the more uncertain the measured abradibility of the yarn is.
[0025] By way of examples of exploitation, the manufacturing processes, conditions and process components, though not limited to the exploitations, of the present invention may be as follows:
EXAMPLES OF EXPLOITATION
Example of Exploitation 1
[0026] Adding to the fiber material polyester particles inorganic titanium dioxide metal particles, with ultraviolet reflection, effect having the following parameters: particles with diameter less than 100 nm and constituting 0.5% of the total fiber; and particles with diameter exceeding 0.3 micro meters or 300 nm and constituting 0.4% weight of the fiber. Conducting spinning at a temperature of 290° C. and at a spinning velocity of 3000 m/minute to produce Partially Oriented Yarn (POY). False twisting the POY at a speed of 600 m/minute to produce Draw Textured Yarn (DTY) with ultraviolet covering effect.
Example of Exploitation 2
[0027] Similar to implementation example 1, the working conditions include spinning and false twisting to produce DTY with ultraviolet covering effect, but inorganic titanium dioxide metal particles of average particle diameter less than 100 nm is added constituting 0.9% weight of the fiber.
Example of Comparison 1
[0028] Similar to implementation example 1, the working conditions include spinning and false twisting to produce DTY with ultraviolet covering effect, but inorganic titanium dioxide metal particles of average particle diameter exceeding 0.3 micrometers or 300 nm is added constituting 0.9% weight percent of the fiber.
Example of Comparison 2
[0029] Similar to implementation example 1, the working conditions include spinning and false twisting to produce DTY with ultraviolet covering effect, but only inorganic titanium dioxide metal particles with average particle diameter over 0.3 micrometers is added into the used polyester particles. The addition percentage constitutes 1.6% weight of the total fiber.
[0030] [Evaluation Result]
[0031] The DTY with ultraviolet covering effect produced according to implementation example 1, implementation example 2, comparison example 1 and comparison example 2 whose specification size is 75 denier has the following properties: size is 75 denier; the strip number is 72; considering the wrap DTY form; the filling use is 75 denier * 72 DTY; tatting 1/1 texture, warp density is 112 strip/inch; filling density is 112 strip/inch; the code weight is 92g/m 2 ; cloth thickness is 0.28 mm; and the fabric opening is 10.6%.
Yarn abradability (m) textile UPF (%) Implementation example 1 14276 60.6 Implementation example 2 40000 66.0 Comparison example 1 5545 36.0 Comparison example 2 2667 66.0
[0032] The DTY with ultraviolet covering effect produced according to implementation example 1, implementation example 2, comparison example 1 and comparison example 2 whose specification size is 150 denier has the following properties: size is 150 denier; strip number is 144; 22G PK knitted; code weight is 220 g/m 2 ; cloth thickness is 1.0 mm; and textile opening rate is 5.3%.
Textile UPF (%) Implementation example 1 114 Implementation example 2 130 Comparison example 1 78 Comparison example 2 126
[0033] From above experimental results the larger the fabric opening rate, the poorer the ultraviolet covering effect. When the fabric opening rate is large, inorganic titanium dioxide metal particles having average particle diameter less than 100 nm can be added to the fiber below 1.0% weight of the total fiber to provide ultraviolet reflection effect, and the fiber can be use to produce fabrics with ultraviolet covering effect. UPF of fabrics having inorganic titanium dioxide with average particle diameter of less than 100 nm is apparently superior than similar percentage weight addition of titanium dioxide particles having average particle diameter greater than 0.3 micrometer or 300 nm. For fabrics containing inorganic titanium dioxide metal particles greater than 0.3 micrometers to have similar ultraviolet reflection and covering effect as fabrics containing inorganic titanium dioxide metal particles less than 100 nm, the addition rate of the 0.3 micrometers fibers has to be increased. However, the increase in addition levels of the latter will most certainly cause poor abradability, most certainly hamper otherwise easy abrasion of thread processing route, most certainly result in short fabric life and will most certainly result in overall bad product quality.
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This invention discloses a fiber filament having ultraviolet ray hiding effect and fabric manufactured from said filament. The ultraviolet ray hiding effect of this invention is obtained by adding inorganic titanium dioxide particles having average diameter of less than 100 nm and constituting preferably less than 1 weight % of the total fiber. When fiber filaments of this invention are used in fabric production they constitute preferably over 50% weight of the fabric. thereby producing a fabric with opening rate preferably in excess of 0.7% but preferably less than 25%. The Ultraviolet Protective Factor (UPF) of said fabric is preferably over 40%.
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CROSS REFERENCE TO RELATED APPLICATIONS
The present application is a continuation application of application Ser. No. 13/031,367, filed Feb. 21, 2011, which is a continuation of application Ser. No. 12/429,177, filed Apr. 23, 2009 (now U.S. Pat. No. 7,906,048) and claims the benefit of U.S. Provisional Patent Application No. 61/125,214 filed on Apr. 23, 2008; the entire disclosures of which are hereby fully incorporated by reference as part of the present application.
FIELD OF THE INVENTION
The present invention relates generally to thermoplastic molding methods and apparatus, and more particularly pertains to methods and apparatus for injection molding thermoplastic.
BACKGROUND
Injection molding machines are expensive to purchase, require expensive factory space and substantial quantities of electrical power. Additionally, set-up and operation of injection molding machines is a highly subjective trade, wherein there are significant set-up charges each time a tool is set. Starts and stops of such machines can be very expensive and there are always technicians and/or operators directly involved in such activities. The general practice on start up of an injection molding machine is provide an initial machine configuration (e.g., screw rotation rate, operable screw barrel temperature, injection pressure, etc.), then a “purging” process is performed where an operator first confirms that the injection molding machine is not connected to a mold, and then commences to process plastic but discarding the resulting plastic melt until the operator judges that the output plastic looks hot enough and appears to be of a low enough viscosity to commence molding test parts. Subsequently, a plurality of test parts are produced for inspection and/or analysis to thereby determine whether the machine is configured appropriately to successfully produce parts having the intended characteristics (e.g., fully conforming to the intended part shape, density, elasticity, etc.). Accordingly, the machine settings are generally fixed for mass producing the part.
The above described injection molding practice has substantial problems in that various part affecting parameters can change during the part mass production. For example, the operator settings may not be adequate for keeping the injection machine in a state for maintaining part consistency. In particular, it may not be possible to adequately determine whether the plastic is sufficiently uniformly heated so that acceptable parts can be produced therefrom. Additionally, since patches of plastic raw material inherently vary in their composition, variation in part production may be necessary dependent upon variation in the plastic raw material. Furthermore, the various injection molding parameters (whether settable by an operator or not) are generally interrelated with respect to producing acceptable parts. For instance, (a) nozzle injection pressure and plastic flow rate are inversely related, (b) plastic flow rate and plastic temperature are generally directly related, and (c) changes in screw rotation may generally be directly related to plastic temperature, although such may depend on the degree to which plastic heating is performed by shearing of the plastic in the screw barrel. Accordingly, it is very difficult to effectively and consistently configure a conventional injection molding machine to produce acceptable quality parts, and for very small quantities of parts the overhead for configuring such a machine can unacceptably expensive.
Accordingly, it would be advantageous to have an injection molding system and method of operation that is substantially more cost effective to manufacture and operate. Additionally, it is desirable for such a system and method to be less dependent upon operator trial and error to configure such systems for consistently producing acceptable quality parts.
SUMMARY
A thermoplastic injection molding system and method of use is disclosed for molding parts from heated plastics and other organic resins, wherein the system includes an injection molding machine and a controller for controlling the machine such that when the controller is supplied with input from various machine sensors providing real time measurements related to the characteristics of the plastic or resin (collectively referred to a “plastic” hereinbelow) in the injection molding machine, the controller dynamically adjusts the injection molding process to achieve more consistent and reliable molded parts.
The injection molding machine disclosed herein includes a screw for transporting the solid unmolded plastic material (e.g., pellets) from a storage container or hopper to an injection zone or chamber for collecting melted plastic in preparation for injecting the melted plastic therein into mold. The screw is configured within a barrel or cylinder in a manner that substantially prevents the plastic being conveyed therein from being sheared, and in particular, prevents such shearing between the barrel and the screw. Accordingly, the rotation of the screw when conveying plastic requires substantially less torque than prior art injection molding machines having a screw that shears the plastic. In particular, the tolerances and configuration of the screw within the barrel are such that the gaps between the inside diameter of the barrel and the outside diameter of the screw are small enough so that the plastic pellets cannot be sheared therebetween. Moreover, the barrel (and plastic therein) is heated, insufficient heat is applied to allow the plastic to deform into such gaps and be sheared, and insufficient heat is applied to induce the plastic to adhere to the screw flutes or the inside of the barrel for substantially an entire length of the screw. Thus the present injection molding machine uses substantially less energy to rotate the screw. Furthermore, the screw can be easily removed from the barrel since both the screw and barrel are substantially free of adhered to plastic.
Due to the screw being primarily a conveyance mechanism for the plastic pellets, the screw can be designed for efficient and effective conveyance rather than for shearing. Moreover, a result of such a screw design in the present injection molding machine is that the pellets compact within the barrel as they travel toward and ultimately enter plastic melting zones of the present injection machine. Such compaction has a particular advantage of effectively providing a barrier for preventing melted plastic from leaking or flow backward in the injection molding machine. Accordingly, a valve for preventing such flow back is unnecessary. However, in the event that such compaction is diminished enough so that there is plastic melt flow back, there may be one or more thermocouples or other heat sensors for detecting an inappropriate increase in heat, and providing such information to the controller (e.g., a computer system specifically configured for controlling the production of parts by the present injection molding machine, and/or programmable logic controller), wherein one or more of the following may be initiated by the controller: an operator may be alerted, the screw rotation rate at least temporarily increased, shutting down the mold injection machine (e.g., in the event that there are insufficient plastic pellets in the hopper), activating a pellet jam breaking mechanism for jams in the hopper, and/or activating a mechanism for automatically feeding additional pellets to the hopper.
The hereinabove described screw and a corresponding extent of the barrel may be considered as a first zone of the injection molding machine, wherein there is a series linearly aligned injection molding machine zones for transforming the plastic into a melt acceptable to mold parts. At the end of this first zone (e.g., substantially where the plastic pellets compact), a second zone commences wherein one or more heat sources (controlled by the controller) are active for heating the plastic within this zone so that the plastic becomes flowable. In general, the increase in heat over that of the first zone may be only a few degrees above the heat applied in the first zone (e.g., an increase in temperature in a range of 25-250° F.). The heat sources may be one or more of a resistance, inductance or ultrasonic heat source. These heat sources are positioned and arranged so that the heat generated affects the plastic, within a relatively short portion of the screw, and substantially at the termination of the screw flutes, so that the plastic becomes flowable. More specifically, the plastic becomes sufficiently flowable (due to pressure of additional upstream plastic moving into this second zone) to flow downstream through heating channels of a third zone described hereinbelow. Since most plastics do not conduct heat well, the second zone (also known as the “transition zone” herein) may be configured so that there is an increase in heated surface area for contacting the plastic within this second zone. In one embodiment, such an increase in heated surface area may be at least partially due to a heated annular interior barrel wall that serves as an intermediary barrel portion for connecting the barrel interior of the first zone to the downstream third zone having a barrel interior of reduced cross sectional dimension. In particular, the portion of the barrel extent for the first zone may have a first diameter in a range of, e.g., 2 inches to 10 inches, and the interior dimension of the third zone may have a diameter in a range of, e.g., 40% to 60% less. Such a heated wall provides a substantial increase in surface area for transmitting heat to the adjacent plastic. Moreover, such a wall can be configured to be substantially perpendicular to the general helical path of the plastic to thereby induce a buildup of plastic (and corresponding pressure which may be in a range of 100-5000 psi (pounds per square inch)) adjacent to and in contact with this wall for facilitating heat transfer to the plastic. Additionally, the terminal end of the screw within the second zone may terminate in a substantially convex shape (e.g., a truncated conical surface which forces the plastic closer the heated wall). In one embodiment, this terminal end of the screw may also radiate heat via, e.g., one of the heat sources identified hereinabove.
It is worthwhile to note that since sufficient heat to induce adherence of the plastic to internal machine surfaces only commences in the second zone, and since this zone is of short length (relative to the screw length and the length of the machine) any plastic that adheres to the internal machine surfaces in this second zone (e.g., due to a machine shutdown or heat interruption) will not be so substantial that the screw cannot be readily extracted from the barrel. In particular, the linear extent of the total barrel residing in the second zone may be only 2% to 10% of the length of the screw, and there may be few (if any) screw portions (e.g., attenuated screw flutes) in this second zone where there could be a sufficient buildup of resolidified plastic that would substantially inhibit the screw from being extracted without damaging some portion of the machine or without disassembling the barrel screw combination from the remainder of the machine.
In the third zone following the second or transitional zone, the flowable plastic is forced by pressure buildup in the second zone, to flow through one or more (preferably a plurality of) channels of this zone, wherein such channels conduct the plastic through the length of this third zone, and into a fourth or injection zone described hereinbelow. The channels may be distributed circumferentially about an extension of the screw shaft, wherein in at least one embodiment this extension includes an injection plunger that reciprocates along the rotational axis of the screw for repeatedly injecting melted plastic into a mold. Each channel may extend parallelly to the shaft axis between a receiving opening for receiving plastic, and an exit opening from which the plastic exits. The third zone is also heated by one or more of the heat sources for continuing to elevate the temperature of the plastic provided therein. Moreover, since the channel(s) may substantially increase the heated barrel surface area in contact with the plastic, the plastic in the channel(s) liquefies, or substantially reduces its viscosity so that it may flow into the injection zone (when not prevented) at a rate in direct proportion to the number of screw rotations realized within the system. The temperature increase in the plastic due the heat imparted via the channel(s) may be in a range of 25-250° F. Note that the heat sources for this third zone may be external to the portion of the barrel for the third zone, embedded within the barrel, and/or provided by the extension to the screw shaft (such extension may have a length of, e.g., 1.5 inches to 12 inches depending on the size and plastic processing capacity of the present injection mold machine).
In at least some embodiments, the shaft extension extends (along the axial length of the barrel) substantially the entire length of the third zone. However, when the plunger is fully retracted into the screw shaft, the exit opening(s) of the channel(s) opens into the injection zone so that melted plastic can exit the channel(s) and into this injection zone. Thus, since the melted plastic is typically under pressure (e.g., a range of 100-1000 psi) in the channel(s), and there is a reduced pressure in the injection zone (e.g., ambient atmospheric pressure), plastic will flow out of the channels and into the injection zone whenever such a pressure differential exists. However, when the plunger extends into the injection zone for forcing plastic into a mold, such extension closes the channel exit opening(s) so that there is substantially no backwards flow of plastic from the injection zone into the channel(s) due to the plunger induced pressure increase in the injection zone. Accordingly, the plunger serves a dual purpose of both forcing melted plastic into the mold, and also iteratively opening and closing the channels to the injection zone. So, in particular, the present injection mold machine requires no separate valve for metering the plastic melt into the injection zone.
The fourth or injection zone (also identified as a “plastication zone”) includes an injection chamber for receiving plastic from the channels, and an injection tube through which plastic flows from the injection chamber to an injection nozzle which is attached to the mold for providing plastic therein. As with other plastic conveying portions of the present injection molding machine, the injection chamber and the injection tube are connected so that the melted plastic flows generally in a straight path along the axis of the barrel. Thus, this linear arrangement prevents plastic pressure drops which can occur where the pressurized liquid plastic is constrained to abruptly flow in substantially different directions (e.g., around a 90 degree corner).
The injection zone also includes one or more of the heat sources for providing additional heat to the plastic provided therein. As with the heat sources in the other zones, the heat sources for the injection zone are controlled by the controller (e.g., a computer system specifically configured for controlling the production of parts by the present injection molding machine, and/or programmable logic controller),
It is worthwhile to note that in one embodiment of the present injection mold machine, a vacuum controlled break valve is provided for control of gas (e.g., air) entering the injection zone. In particular, the vacuum break valve allows air to enter the injection chamber when the injection plunger lowers the pressure within the fourth zone (in particular, the injection chamber) due to the plunger retracting from the injection chamber and into the screw shaft extension. In at least one embodiment, the vacuum break valve is provided along a shaft of the plunger, wherein this plunger shaft reciprocates into and out of the screw shaft. Accordingly, when a lower pressure (e.g., lower than ambient atmospheric pressure) occurs in the injection chamber, the vacuum break valve opens to introduce air into the injection chamber as will be described further hereinbelow. During plunger retraction (toward and/or into the screw shaft), the vacuum break valve remains open until (or just before) the plunger retracts sufficiently so that the channels are open to the injection chamber, and then the valve closes hereby preventing the melted plastic entering the chamber from exiting via the valve.
It is additionally worthwhile to note that when plastic is urged under pressure into the injection chamber, the heated gas (e.g., air) therein readily escapes as a backflow product through, e.g., the channel(s). Such gas backflow is facilitated in the present injection molding machine since the screw does not tightly fit within the barrel, and thus, gas can escape into the barrel (via the channel(s)) as plastic enters the injection chamber. Empirical evidence indicates that when the present injection molding machine is operating for molding acceptable parts, the pressure in the channels is effective for rapidly filling of the injection chamber with melted plastic. Accordingly, it is believed that the melted plastic enters the injection chamber at sufficient velocity to fill this chamber with melted plastic beginning with the opposite end of the chamber from the chamber end that repeatedly provides the plastic via the channel(s). Accordingly, since the exit opening for providing plastic from the injection chamber to the injection tube is located in this opposite end of the injection chamber, when the high velocity plastic commences to fill the chamber, it does so from the chamber opposite end. Consequently, the gas within the injection chamber is displaced from this opposite chamber end thereby substantially preventing gas pockets from being trapped within the plastic proximate exit opening. Moreover, since it is believed that the melted plastic collects within the chamber from this opposite end first, the gas within the chamber is forced to travel backward toward the channel opening(s) as the melted plastic under pressure injects into the injection chamber. In some embodiments, such channel opening(s) may be shaped to facilitate the melted plastic filling the injection chamber from the opposite end to the chamber end having the channel opening(s). In particular, such channel opening(s) may be shaped to direct the melted plastic into particular portions of the injection chamber. For example, the channel opening(s) may be shaped so that when the channel(s) initially opens, melted plastic is directed generally toward the interior of the opposite end of the chamber, and as the channel opening(s) widens, the melted plastic may be generally directed to a portion of the axial centerline of the plunger reciprocation wherein this portion is progressively closer to the channel opening(s). Accordingly, the gas backflow may be generally along or adjacent to the chamber sides providing relatively direct backflow paths to the channel open(s).
Moreover, it is aspect of the present injection molding machine, that since such escaping gas is heated to substantially the temperature of the injection chamber, this gas may be reused to facilitate the heating of the plastic in the second and/or the third zones. Alternatively/additionally, such heated gas may also be recirculated back into the injection chamber via the vacuum break valve described above. Accordingly, the recycling/reuse of the heat within the escaping gas increases the efficiency of the present injection molding machine.
Further note that in one embodiment, there may be backflow vents separate from the above described channels, wherein such backflow vents do not conduct melted plastic into the injection chamber.
The injection tube of the fourth zone may be of reduced cross sectional area in comparison to the injection chamber, and additionally may be of sufficient length to contain at least one volume of plastic from the injection chamber, but generally less than two such volumes. Accordingly, since the injection tube has an increased surface area (relative to volume) in comparison to the injection chamber, and is also heated, the plastic therein is acceptably liquefied for mold injection. However, due to the relatively small volume of plastic therein, the energy consumption of the injection molding machine is reduced over similar prior art injection molding machines.
The fourth zone may also include a programmable nozzle valve at or proximate to the injection nozzle, wherein this valve opens to release melted plastic in a mold cavity when there is sufficient pressure within the injection nozzle.
It is an aspect of the present injection molding machine that the controller mentioned hereinabove receives various sensor readings indicative of plastic temperatures, plastic pressures, and plastic viscosity. In particular, the controller receives the following measurements from the injection molding machine:
(a) A pressure measurement from a screw pressure sensor at the end of the screw opposite the screw end terminating in the second zone. When the screw rotates to push the plastic pellets forward, there is a corresponding back pressure induced to push the screw in the opposite direction from the direction to pellets move. Such back pressure is related to the quantity of pellets being moved by the screw, and more importantly, the quantity of pellets being compacted in the second zone. Accordingly, unless a predetermined back pressure is sensed by the controller from the screw pressure sensor providing such pressure measurements, the activation of the plunger will not commence, or if already reciprocating, the plunger may cease to reciprocate until a threshold pressure is detected by the controller from the screw pressure sensor. (b) A temperature sensor in the first zone for monitoring the temperature of the plastic pellets and/or the barrel in this zone. Accordingly, the controller controls the one or more first zone heating devices so that the pellets are heated just below their softening or deforming temperature in the first zone. (c) A chamber pressure sensor for sensing pressure within the injection chamber. Unless there is at least a predetermined pressure within the injection chamber, the injection plunger will not be activated to send a plastic pressure wave into the injection tube and consequently cause melted plastic to be injected into a mold cavity. Accordingly, the present injection molding machine only forms parts when an appropriate pressure is registered by this pressure sensor. (d) A tube temperature sensor located in the injection tube, at or proximate to the nozzle. Unless the plastic and/or the injection tube is determined to be of a threshold temperature (e.g., specific to the plastic), the plunger will not be activated, and the nozzle valve will not be opened to allow plastic to be injected into a mold cavity. (e) A tube pressure sensor located in the injection tube, at or near the nozzle. Unless the plastic is determined to have a threshold pressure within the injection tube (such pressure obtained from the most recent injection(s) of plastic via the plunger), the nozzle valve will not be opened to allow plastic to be injected into a mold cavity. Accordingly, the plunger may be activated a plurality of times between openings of the nozzle valve or activated only with nozzle valve opening depending on the pressure requirements for the plastic within the injection tube. In some embodiments, the controller may use the tube pressure for determining a length of time the nozzle valve may be allowed to be open since the pressure on the melted plastic in combination known viscosity characteristics of the plastic at the tube temperature can be used to determine the amount of plastic that will be injected into a mold cavity.
It is a further aspect of the present injection molding system that it may achieve plastic and resin plastication through the conduction of electrically generated heat as opposed to pressure induced shear heat generation methods currently used by most injection molding machines. The conduction of electrically generated heat provides a process of plastication that is more accurate than shear generated heat. Additionally, since there is also a reduced pressure applied to the plastic (due to the lack or substantially reduced shearing), the injection molding machine may be used to mold parts from non-traditional materials (e.g., bio-based resins of any type, metal injection molding feedstock, and liquid silicone) that would degrade under shearing, and may be used to produce part with enhanced performance characteristics.
It is a further aspect of the present injection molding system and method of use that there may be continuous material plastication that preserves the plastic/resin quality with exact application of prescribed levels of heat to known volumes of plastic/resin. This method dramatically reduces the force and strength requirements for the subsequent injection process (via the plunger), thereby allowing a more accurate and responsive delivery of melted plastic/resin into an injection mold cavity.
It is a further aspect of the present injection molding system and method of use that integrated pressure and temperature sensors may be used by the controller to accurately quantify the output of the present injection molding machine, and in particular during the injection molding cycle for perfecting changes to the injection molding process in order to affect parts being produced. This is accomplished even when variations in the raw material are present. Moreover, such real time mold injection process changes are provided by an injection mold controller that is data-driven from measurements obtained from sensors provided in the injection molding machine. In particular, such a data-driven machine and method results in various components of the present injection molding machine having activations that are more asynchronous to one another than the lock step or a predetermined non-deviating sequence of steps prevalent in the prior art.
It is a further aspect of the present injection molding system and method that this system can initiated without an operator present (assuming the proper mold is connected to the injection molding machine, and this machine is appropriately clean). Moreover, the presently disclosed injection molding system and method can also operate unattended for molding parts. Thus, activation and operation of the present injection molding system may be performed automatically and remotely such as via a communications network (Internet) activation, wherein the present injection molding system and method remain unattended while producing the desired parts.
The above described aspects of the present injection mold system and method were combined at least in part due to the recognition of the longstanding unmet drawbacks in various prior art injection molding machines and methods. Moreover, even relatively recent supposedly improvements in plastic injection mold technology have substantial drawbacks. For example, the following recent references have been considered, and are incorporated herein by reference:
U.S. Patent Application Publication No. 2003/0021860 by Clock et. al. filed Jul. 24, 2001, wherein an injection molding apparatus is disclosed that includes: an extruder configured to receive and compound raw materials, a plunger disposed longitudinally within the extruder, and a mold positioned at the outlet end of the extruder and configured to receive the compounded raw materials. The extruder includes first and second screws intermeshed with each other along at least a portion of the length thereof. The plunger is typically positioned longitudinally within a bore defined within the first screw and is translatable within the bore. The method for using the apparatus includes adding at least one material to the extruding unit proximate a first end thereof, compounding the material, transporting the material to an outlet port proximate a second end of the extruding unit, and transferring the material from the outlet port to the mold via a reciprocating action of the plunger relative to the first screw. The Clock application discloses a check ring for preventing back flow of the liquid plastic out of an injection chamber. Such a check ring: can be unreliable, and introduce inaccuracies into the quantity of the plastic injected into a mold due to both the variability in the closing by the check ring as well as the restrictions to plastic flow therethrough. Note that such impedances to plastic flow are magnified in that such check rings are typically heat sinks; thus, causing the plastic to flow less readily. Moreover, it appears that the Clock's plunger (also a heat sink having sizable plastic contacting surface area) must rotate with the screw. Accordingly, since it is irregularly shaped (e.g., there are flutes therein), there is unnecessary drag on the motor rotating the screw. Additionally, since the check ring is not monitored during operation for determining if it is performing properly, there can be significant variability in parts produced, and for which machine configurations settable by the operator may have an unpredictable (if any) effect. U.S. Patent Application Publication No. 2002/0020943 by Leopold et. al. filed May 9, 2001, wherein a molding machine is disclosed for molding microparts containing between 0.001 to 3.5 cubic centimeters of plastic shot volume includes a plasticizing portion operatively connected to an injection portion and a mold portion. A valve member is provided to open and close the connection between the plasticizing portion and the injection portion. A linear motor member is associated with the injection portion to permit molding times of presumably 0.01 seconds at pressures up to about 100,000 psi during injection of the molten plastic into the mold portion. Leopold discloses using a valve for apparently allowing melted plastic to flow into a bore for injection into a mold. Moreover, Leopold also needs an additional valve at his injection nozzle. There are reliability problems with such valves since a temperature decrease of the plastic in or around such valves can cause these valves to malfunction due to an increase in the viscosity or solidification of the plastic. Moreover, such valves are particularly problematic if the plastic includes one or more filler materials that may be fibrous since such valves may fail to fully close and/or open due to fiber build up or compaction in or around the valves.
Other features and benefits of the presently disclosed injection molding machine and method of use are disclosed in the accompanying figures, and the description hereinbelow. In particular, various novel aspects of the presently disclosed injection molding machine and method not described above may be described hereinbelow. Accordingly, this Summary section is intended to present a general overview of the present injection molding machine and method of use, but may not identify every patentable aspect thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of the machine showing the logical connections between the machine and the controller in one embodiment of the present disclosure;
FIG. 2 is side elevation view of the machine;
FIG. 3 is a cutaway side view of the machine showing the logical connections between the machine and the controller in one embodiment of the present disclosure;
FIG. 3A is a detailed cutaway side view of portions of the plunger 160 ;
FIG. 4 is a cutaway side elevation view of the machine;
FIG. 5 is a cross-sectional view of the machine at a point indicated as A-A in FIG. 3 , viewed from left to right with reference to FIG. 3 ;
FIG. 6 is a cross-sectional view of the machine at a point indicated as B-B in FIG. 3 , viewed from left to right with reference to FIG. 3 ;
FIG. 7 is a cross-sectional view of the machine at a point indicated as C-C in FIG. 3 , viewed from left to right with reference to FIG. 3 ;
FIG. 8 is a cross-sectional view of the machine at a point indicated as D-D in FIG. 3 , viewed from left to right with reference to FIG. 3 ;
FIG. 9 is a detailed partial cutaway side elevation view of the machine; and
FIG. 10 is a block diagram showing components of the system 12 , which includes machine 20 and controller 16 in one embodiment of the present disclosure.
FIG. 11 is a block diagram of the injection molding system 12 .
FIG. 12 is a flowchart of the processing performed by the controller 16 .
DETAILED DESCRIPTION OF THE INVENTION
In order to more fully appreciate the present invention, the following references are fully incorporated herein:
U.S. Pat. No. 7,122,146 by Akopyan, filed Apr. 18, 2005, wherein an injection molding machine utilizing microwave heating is disclosed. In particular, a microwave oven and a microwave absorbent plasticizing vessel therein, is utilized in an injection molding system to heat polymer granules to an injection temperature and injection of a resulting plastic melt into a cavity of an injection mold. The polymer granules may be preheated by conventional heating systems to a temperature at which the granules become microwave absorbent before heating to the injection temperature in the microwave oven. The injection molding machine also contains a hydraulic actuator for injection of the resulting plastic melt. The ceramic materials forming the plasticizing vessel are selected to provide equal heating rates of mold members and relatively uniform heating of polymer to desired injection temperature. U.S. Pat. No. 7,361,294 by Pierick et. al. filed Feb. 2, 2005, wherein an injection molding system and method is disclosed for making microcellular foamed materials are provided as well as microcellular articles. U.S. Patent Application Publication No. 2006/0197254 by Onishi filed May 2, 2006, wherein an induction-heating-type heating apparatus is attached to an area of the outer circumference of a heating cylinder adjacent to a cooling apparatus, whereby the temperature of the heating cylinder can be uniformly controlled to a proper value, and the temperature of the heating cylinder can be changed quickly. An injection apparatus is adapted to intermittently feed forward a resin within a heating cylinder by a screw in accordance with an injection molding cycle. The injection apparatus includes a cooling apparatus attached to a rear portion of the heating cylinder, and an induction heating apparatus attached to the heating cylinder to be located forward of the cooling apparatus and adjacent to the cooling apparatus. U.S. Patent Application Publication No. 2007/0104822 by Okabe filed Jun. 23, 2006, wherein a plasticizing apparatus is disclosed for use with a resin material wherein the apparatus is reduced in size and wherein a plastication state of a resin material is presumably stabilized without raising a heating temperature for a plasticizing barrel. On the inner surface of a plasticizing barrel for plasticizing the resin material, one or more lines of a heat transfer pieces shaped like a ridge is/are disposed in a protrusion condition in a spiral or a straight line, and on the outer surface of the barrel, one or more lines of a heat receiving piece is/are disclosed. U.S. Patent Application Publication No. 2009/0057938 by Zhang filed Aug. 28, 2007, wherein a method is provided for improving melt quality in an injection unit. A closed loop control system regulates operation of the injection unit in accordance with a reference value for at least one operating parameter. A sensor measures the present e1 value of a load upon the motor which drives an injection screw during operation of the injection unit. A processor compares the present value of the load to a reference value for the load. If the present value of the load deviates from the reference value of the load by more than a predetermined amount, then the processor may adjust the reference value of the at least one operating parameter. Operating parameters can include barrel temperature, back pressure and screw RPMs. U.S. Patent Application Publication No. 2009/0045538 by Davina et. al. filed Aug. 13, 2007, wherein a method of controlling a screw in a two-stage injection unit and a system for implementing the method is disclosed. The method is executable at a computing apparatus associated with the two-stage injection unit. The method comprises receiving an indication of an operational parameter associated with the screw of the two-stage injection unit; based on the indication of the operational parameter, determining a target speed (STARGET) for the screw, the target speed (STARGET) being sufficient to enable the screw to produce a required amount of material in a molten state; causing the screw to rotate at the target speed (STARGET), thereby causing the screw to operate in a substantially continuous manner.
The above-identified references each have their own corresponding drawbacks that make them at most partially useful in addressing injection molding machine related problems.
An embodiment of the presently disclosed injection molding system 12 is shown in FIG. 1 , wherein a controller 16 is shown together with the injection molding machine 20 that the controller 16 controls. The injection molding machine 20 will be first described hereinbelow, followed by a description of the controller 16 .
In reference to FIGS. 3 and 4 , a cross sectional view of an embodiment of the injection molding machine 20 is shown. The machine 20 includes a material hopper 24 for providing plastic material (e.g., plastic pellets) to the machine 20 , wherein the pellets, by gravity, enter a substantially vertical escapement 28 below the hopper 24 . The escapement 28 may be an opening in a throat block 32 which may be a metal block (e.g., cube or other shape) acceptable for providing support and stability to the material hopper 24 attached thereto as well as various components of the machine 20 . In particular, the throat block 32 includes generally horizontal barrel opening 36 therethrough which intersects with the escapement 28 . The barrel opening 36 is fitted with a barrel 40 that extends horizontally beyond the throat block 32 out one of the sides of throat block 32 . The throat block 32 also includes a plurality of water channels 42 for circulating coolant (e.g., water or other suitable coolant) therein since, as will become evident from the description hereinbelow, excessive heat from the plastication of the pellets may transfer into throat block 32 and heat the pellets in the escapement 28 or the hopper 24 excessively (e.g., wherein the pellets might be soft). The barrel 40 provides the structural support within which the pellets are transformed into a suitable liquid state for injection into a mold 46 . The barrel 40 includes a first stage 44 extending substantially through the throat block 32 and out of the throat block to the right in FIG. 3 . This first stage 44 is coincident in extent (along the axis 112 ) with the first zone described in the Summary section hereinabove, and accordingly such an extent may be also referred to as the first zone 44 . A cross section of the first stage 44 (in a direction traverse to the cross section shown in FIG. 3 ) is shown in FIG. 5 . However, a cylindrical shape may be preferred. The first stage 44 may have a cylindrical interior extending therethrough. The first stage 44 terminates outside the throat block 32 at an interior annular wall 48 which reduces the interior of the barrel 40 . From this annular wall 48 and extending further away from the throat block 32 is a second stage 52 of the barrel 40 , this second stage being coincident in extent (along the axis 112 ) with the second zone described in the Summary section hereinabove, and accordingly such an extent may be also referred to as the second zone 52 . This second stage 52 may have a generally cylindrical shaped interior which has center axis collinear with a center axis of the first stage 44 . However, instead of having a smooth cylindrical interior surface as the first stage has, the second stage 52 includes a plurality of channels 56 in its interior side wall 58 (a representative cross section of the second stage 52 is shown in FIG. 6 ), wherein these channels extend outwardly from the center axis and such channels may be distributed about the circumference of the second stage. Since the channels 56 extend through the horizontal length of the second stage 52 , the second stage terminates with channel openings at each end of the second stage. The end of the second stage distal from the first stage 44 is integral with a third stage 60 which has therein a cylindrical injection chamber 64 that may be of the same diameter as the second stage (excluding the channels 56 ), this third stage being coincident in extent (along the axis 112 ) with the third zone described in the Summary section hereinabove, and accordingly such an extent may be also referred to as the third zone 60 . The injection chamber 64 has a horizontal center axis that is collinear with the center axes of the first and second stages 44 and 52 . The injection chamber 64 extends away from the second stage 52 until a second diameter reducing annular interior wall 68 is reached, wherein a central opening 72 in the wall 68 ( FIG. 9 ) may have a center point on the center axis of the injection chamber 64 . From this second annular wall 68 , a fourth stage 76 of the barrel 40 commences which includes an injection tube 78 that extends from an opening 72 in the second wall 68 to a nozzle end 80 of the machine 20 , wherein the nozzle end is configured for attaching to the plastic injection mold 46 and injecting melted plastic therein as one skilled in the art will understand. Note that this fourth stage is coincident in extent (along the axis 112 ) with the fourth zone described in the Summary section hereinabove, and accordingly such an extent may be also referred to as the fourth zone 76 . In comparison to the diameter of the injection chamber 64 , the injection tube 78 includes a substantially reduced diameter cylindrical interior. Moreover, near or substantially at the nozzle end 80 , there is a nozzle valve 82 which opens and closes under the direction of the controller 16 . The nozzle valve 82 remains closed until a desired plastic consistency and pressure is detected within the injection tube 78 . Once such conditions occur in the injection tube 78 , and assuming the mold 46 is in a state wherein plastic can be accepted, the nozzle valve 82 is opened by the controller 16 for providing plastic to the mold cavity 83 .
The barrel 40 also includes an opening 84 for receiving plastic pellets from the escapement 28 . Such pellets enter the barrel 40 and are retained between the flights 88 of an auger screw 92 (also “screw” herein) provided within the barrel. The screw 92 is preferably concentric or coaxial with the barrel 40 . The screw 92 includes a shaft 96 from which one or more helical flights 88 project outwardly therefrom, and such flights 88 extend from generally below the escapement 28 through the first stage 44 of the barrel 40 . The shaft 96 also extends horizontally in the opposite direction from the escapement 28 , wherein a thickened shaft portion 100 adjacent to the throat block 32 is secured thereabout with a bearing 104 , which is provided within a mounting plate 108 , which is fixedly attached to the adjacent side of the throat block 32 . Accordingly, the bearing 104 supports and maintains alignment of the screw 92 within the barrel 40 so that the screw can rotate about a center axis 112 of the barrel, this center axis including the center axes for each of the first, second, third, and fourth stages of the barrel as described hereinabove. In particular, the screw 92 diameter within the barrel 40 is smaller than the interior diameter of the first stage by a tolerance of approximately 0.01 to 0.08 inches so that the screw can rotate freely within barrel when there is no plastic in the barrel to impede such free rotation. Note that the tolerance between the interior of the first stage 44 and the screw 92 may be dependent upon the intended size of the plastic pellets to be provided in the material hopper 24 since such tolerance is intended to be small enough so that such pellets cannot be caught and sheared between the interior surface of the first stage 44 and the portions (apexes) of the auger screw flights 88 that rotate closest to the first stage interior surface. Accordingly, the tolerance range above is believed appropriate for pellets that are approximately 0.125 inches in width, height and depth, pellets being a standard size for use in injection molding machines.
The shaft 96 also extends beyond the mounting plate 108 , wherein a pulley 116 is also secured thereabout. For rotating the screw 92 , a belt (not shown) is provided in the annular recess 120 of the pulley 116 and also provided about a pulley of a drive motor (also not shown) for rotating the pulley 116 and consequently the screw 92 .
The screw 92 has a central bore 124 therethrough, the center axis of the bore is coincident with the center axis 112 . Within the bore 124 there is an injection plunger 160 (having a plunger head 132 and a plunger shaft 136 ), and a plunger shank 140 . The plunger shank 140 extends from the screw 92 rearward beyond the pulley 116 . Prior to exiting the screw 92 , the plunger shank 140 and the interior surface of the bore 124 are intermeshed via mating gear teeth 142 or another mechanism for both supporting the shank 140 within the bore 124 , and for allowing the shank to shift along the center axis 112 under the urging of the motor (or pneumatic cylinder, hydraulic cylinder) 144 to which the shank end attaches via a bearing 148 . In another embodiment, instead of mating gear teeth 142 , a bearing that allows the shank 140 to move in the axial direction relative to the bore 124 and provide support for the shank 140 within the bore 124 may replace the mating gear teeth 142 . Accordingly, the bearing 148 allows the shank 140 to rotate with the rotation of the screw 92 by the pulley 116 . However, when activated (by the controller 16 , also shown in FIGS. 1 and 3 , and described hereinbelow) the motor 144 shifts the shank along the center axis 112 either for pushing the shank further into the screw, or for extending further rearward outside of the screw. In particular, the extent that the shank 140 may shift in either direction does not disengage the shank from the interior of the bore 124 at the shift mechanism 142 . Moreover, length of such a shift (in either direction) may be identical to the travel of the plunger head 132 in the injection chamber 64 as will be further described hereinbelow. The shank 140 attaches, at a second end thereof opposite to the shank end attached to the motor 144 , to a receptacle 152 . In one embodiment, the receptacle 152 may be threaded and the second end of the shank 140 may have corresponding threads (e.g., male-female junction). In particular, the receptacle 152 may threadably mate with the end of the shank 140 .
The sleeve 156 also projects beyond the fluted end of the screw 92 . The portion of the sleeve 156 that extends beyond the end of the screw 92 is within a fine tolerance of the interior surface of the second stage 52 of the barrel 40 . More precisely, the smallest interior diameter of the second stage interior side wall 58 may be within a tolerance of approximately 0.01 inches of the outer diameter of the sleeve 156 . Thus, the sleeve 156 forms a rotatable inner most side of each channel 56 in the second stage 52 . In the present embodiment, the exterior surface of the sleeve 156 forming the inner most channel sides may be highly polished or otherwise provided with a coating that substantially prevents melted or softened plastic from adhering thereto.
The sleeve 156 and the plunger head 132 are sealed together (such combination also referred to as plunger 160 ), and may be considered as an embodiment of the “shaft extension” referred in the Summary section hereinabove. An outside diameter of the sleeve 156 may be within a fine tolerance of the inside diameter of the injection chamber 64 , e.g., within a range of 0.005 to 0.001, so that this sleeve 156 and plunger head 132 combination can enter the injection chamber (via an urging by the motor 144 ) for injecting melted plastic from the injection chamber into the injection tube 78 , and also via an opposite urging by the motor 144 , the plunger 160 can retract out of the injection chamber 64 once the plunger 160 reaches its full extension into the injection chamber 64 .
The plunger head 132 includes a one way vacuum break valve 164 (e.g., a poppet style valve) for opening and providing a gas (e.g., air) or other fluid substance therethrough when a reduced atmospheric pressure occurs in the injection chamber 64 relative to a pressure on an opposite side of this valve, and remaining closed otherwise. When the valve 164 opens, the gas provided to the injection chamber 64 comes, in one embodiment, from within the bore 124 , and more particularly, from within a plunger vent 168 within the plunger shaft 136 ( FIG. 3A ). However, it is within the scope of the present disclosure that such gas may come from a backflow of gas (i.e., in an opposite direction from the flow of plastic toward the nozzle end 80 ) through the channels 56 . The vacuum break valve 164 may be configured for opening when there is a pressure differential between sides of the valve in a range of 2 to 1,000 psi. Accordingly, when the plunger 160 retracts back into the screw 92 , the vacuum break valve 164 opens so that the retraction of the plunger does not cause the melted plastic within the injection tube 78 to withdraw back into the injection chamber 64 .
The injection molding machine 20 also includes a plurality of heat sources (e.g., such heat sources may generate heat via electrical resistance, electrical inductance, microwave or ultrasonic energy) distributed about and in contact with (or proximate to) various portions of the barrel 40 . In particular, one or more such heat sources 172 may surround the barrel 40 in a later or terminal portion of the barrel first stage 44 near the commencement of the barrel second stage 52 , and continue to surround barrel 44 in substantially the second stage 52 . The heat sources 172 (under the control of the controller 16 ) preheat the plastic pellets to a point just below the softening point of the plastic.
The heat sources 172 (under the control of the controller 16 ) heat the plastic pellets therein to a temperature where they become at least soft and deformable for flowing into the channels 56 due to the pressure exerted on such deformable pellets from additional pellets moving into the second stage 52 .
The steps performed by the controller 16 for appropriately activating and deactivating the heat sources 172 are described hereinbelow in the section entitled “Controller Operation”. Note that in one embodiment, an additional heat source 176 (not shown in figures) may be placed on a different location of the barrel 44 and controlled by controller 16 . Note that in such an embodiment of the controller 16 the heat sources 172 and 176 are activated and deactivated in unison by the same processing in the controller 16 . That is, the controller may not distinguish between the heat sources 172 and 176 . In another embodiment, heat sources 172 and 176 may be activated, for example, in a serial or sequential manner.
An additional one or more heat sources 180 may surround the barrel 40 in substantially its third stage 60 and fourth stage 76 . The heat sources 180 (under the control of the controller 16 ) further heat the plastic in the injection chamber 64 and the injection tube 78 so that the temperature of the plastic is above a minimum threshold to be injected into the mold cavity 83 . The steps performed by the controller 16 for appropriately activating and deactivating the heat sources 180 are also described hereinbelow in the section entitled “Controller Operation”.
The injection molding machine 20 also includes a plurality of sensors for communicating measurements related to plastic processing to the controller 16 . In one embodiment of the injection molding machine 20 , there is a screw 92 pressure sensor (denoted “PT 1 ” herein) attached, e.g., to the screw end between the pulley 116 and the motor 144 , wherein this sensor measures the forces on the screw, wherein such forces are substantially along the center axis 112 , and induced by the compaction of the plastic in first and second barrel stages 44 and 52 . Accordingly, such for forces are in the direction for pushing the screw 92 out of the end of the barrel 40 provided in the throat block 32 .
The injection molding machine 20 also includes a plurality of sensors for communicating measurements related to plastic processing to the controller 16 . In one embodiment of the injection molding machine 20 , there is a screw 92 pressure sensor or pressure transducer (denoted “PT 1 ” herein) attached, e.g., to the screw 92 end between the pulley 116 and the motor 144 , wherein this sensor measures the pressure on the screw, wherein such pressure is substantially along the center axis 112 , and induced by the compaction of the plastic in first and second barrel stages 44 and 52 . Accordingly, such for pressure may be considered a force in a direction for pushing the screw 92 out of the end of the barrel 40 provided in the throat block 32 . A temperature sensor (denoted “TC 1 ” herein) is attached to the barrel 40 (more particularly, the third stage thereof) for detecting temperatures in the injection chamber 64 . The sensor TC 1 may be a thermocouple as one skilled in the art will understand. Also attached to the barrel third stage is a pressure sensor or pressure transducer (denoted “PT 2 ” herein) for measuring the pressure within the injection chamber 64 . Downstream from the sensor PT 2 is another pressure sensor or pressure transducer (denoted “PT 3 ” herein), wherein this sensor measures the pressure within the injection tube 78 . Additionally, there is a temperature sensor (denoted “TC 2 ” herein) is attached to the barrel 40 (more particularly, the fourth stage thereof) for detecting temperatures in the injection chamber 64 . The sensor TC 2 may be a thermocouple as one skilled in the art will understand. Finally, there is a temperature sensor (e.g., a thermocouple) provided in the mold 46 for detecting temperatures therein. This last sensor identified as “TC 3 ”. Each of the above identified sensors provides their corresponding readings to the controller 16 as will be described in further detail hereinbelow.
FIG. 11 shows a block diagram of the injection molding system 12 , wherein additional detail is provided of the internal components of the controller 16 . Referring to the controller 16 , it includes a main controller 204 that performs that high level control functionality for controlling the injection molding machine 20 . A flowchart of the processing performed by the main controller 204 is presented in FIG. 12 described hereinbelow. The main controller 204 activates a plurality of subcontrollers that may perform their tasks asynchronously from one another. In particular, subcontroller 304 is provided for controlling the heat source(s) 172 for heating the first and second zones 44 and 52 . A subcontroller 308 is provided for controlling the heat source(s) 180 for heating the third and fourth zones 60 and 76 . A subcontroller 312 is provided for controlling the screw 92 rotation during startup of the injection molding machine 20 , and more particularly, prior to injection molding machine entering a plastic processing state where processed plastic is flowing through the injection molding machine appropriately for making parts. A subcontroller 316 is provided for controlling the screw 92 rotation once plastic is flowing through the injection molding machine appropriately for making parts. A description of each of these subcontrollers is provided hereinbelow. However, prior to providing such descriptions, a description of the flowchart of FIG. 12 representing the processing performed by the main controller 204 is provided.
Referring to FIG. 12 , in step 404 , the controller 16 receives input for activating the injection molding system 12 . Such activation may be from an operator at the injection molding system 12 , or an operator that is remote from the location of the system 12 . Moreover, since the controller 16 can be remote from the injection molding machine 20 (e.g., in communication therewith via a communications network such as the Internet), the operator may reside at the controller site, or at the injection molding machine site. Alternatively/additionally, the operator may not reside at the site for either the controller 16 or the injection molding machine 20 , but instead may communicate with controller via a communications network. Moreover, the input received may be from another computational system such as an inventory management system that automatically requests additional parts to be produced by the injection molding system 12 .
Note that such input may include a type of material to be supplied to the injection molding machine 20 , an identification(s) of the part(s) to be molded, the quantity of parts to be produced.
In step 408 of FIG. 12 , the controller identifies from the input received the type of material to supply to the injection molding machine 20 . Such identification may be precisely identified in the input, or may be only generally identified (e.g., by a plastics chemical family, or by required part functionality such as elasticity, compression strength, biodegradable, acceptable for retention in a human body, non-toxic if ingested, etc. In one embodiment, such material may be automatically supplied to the hopper 24 for commencing to produce the parts desired, and the desired mold 46 may be automatically attached to the injection molding machine 20 , e.g., once the mold is located in an inventory of molds 46 . Subsequently, in step 412 , a database management system 410 ( FIG. 11 ) may be accessed for determining the injection molding machine 20 parameters to use in molding the desired parts.
In step 416 , the subcontroller 304 is activated for controlling the heat source(s) 172 for heating the second and third zones 44 and 52 . The input to the subcontroller 304 may include a desired start temperature range for readings from the temperature sensor TC1 as determined for plastic to be processed; the range of temperatures may be, e.g., +/−10 degrees F., and the range may be a set point range identified as the range [set_pt_low, set_pt_hi] wherein set_pt_low is a low set point for the readings from TC 1 , and set_pt_hi is a high set point for these readings. Psuedo-code representative of the processing performed by the subcontroller 304 is as follows:
Subcontroller 304 processing:
Activate asynchronously (the following processes):
Process 1:
At “X” frequency read input temperature measurement from TC1;
If the input temperature measurements are below “set_pt_low”, then
Make sure the heat sources 172 are activated for heating;
Else make sure the heat sources 172 are not heating;
Process 2:
Repeat every “Y” time interval:
If (Delta12_Not_Measured) then /* “Delta12_Not_Measured” is
set to TRUE after the plunger 160 retracts
into the screw 92
*/
If (the plunger 160 is fully retracted into the screw 92)
then {
Pt1 ←Read PT1;
Pt2 ← Read PT2;
Delta12 ← Pt1 − Pt2;
Delta12_Not_Measured ← FALSE;
If (Delta12 >= its corresponding predetermined set point)
then {
/* either plastic viscosity in screw 92 is high, and/or,
plastic is not flowing through channels 56 into the
injection chamber 64
*/
Tc1 ← read TC1;
If (Tc1 <= set_pt_hi) then
Override Process 1, and make sure the heat sources
172 are heating;
}
Until (subcontroller 304 is deactivated).
Referring to the subcontroller 304 psuedo-code hereinabove, process 1 and process 2 may be activated for being performed simultaneously. However, note that process 2 can override process 1 to force the heat source(s) 172 to heat zones 44 and 52 . It is believed that an important aspect of the controller 16 is the use of the pressure measurements from the sensors PT 1 and PT 2 to modulate the heat delivered to the first and second zones 44 and 52 . In particular, the computation of “Delta 12 ” provides a quantitative index as to whether plastic viscosity in screw 92 is high, and/or the plastic is not flowing through channels 56 into the injection chamber 64 . For example, if the value Pt 1 is high relative to the value of Pt 2 , then there is substantial pressure in the first and second zone 44 and 52 for pushing the screw 92 out the rear end of the injection molding machine 20 , and little (if any) plastic in the injection chamber 64 . Accordingly, this is indicative of the plastic in the second and third zones 52 and 60 not being hot enough to proper flow through the channel 56 and into the injection chamber 64 . Thus, in this case, any deactivation of the heat source(s) 172 is overridden by process 2 . Note that it may be important for the reading of PT 1 and PT 2 to be taken substantially simultaneously, and that the readings of PT 2 be taken when the pressure in the injection chamber 68 is not being impacted by the movement of the plunger 160 into or out of the injection chamber. Accordingly, such reading are only taken when the controller 16 detects that the plunger is fully retracted from the injection chamber 64 . The use of the Boolean variable “Delta 12 _Not_Measured” assists in making sure the readings are taken at a proper time.
In step 420 , the subcontroller 308 is activated for controlling the heat source(s) 180 for heating the fourth zone 76 . As described in the pseudo-code following. Note that the input for this subcontroller is: a desired start temperature range for readings from the temperature sensor TC 2 (for heat sources 180 ) for plastic to be processed, the range of temperatures (e.g., +/−10 degrees F.) creating a set point range, i.e., a range: [set_pt_low2, set_pt_hi2] for the readings from TC 2 .
Subcontroller 308 processing:
Activate asynchronously (the following processes):
Process 3:
At “X” frequency the subcontroller 308 reads input temperature
measurements from TC2;
If the input temperature measurements are below “set_pt_low2”,
then
Make sure the heat sources 180 are activated for heating;
Else make sure the heat sources 180 are not heating.
Process 4:
Repeat every “Y” time interval:
If (Delta23_Not_Measured) then /* “Delta23_Not_Measured” is
set to TRUE after the plunger 160 retracts
into the screw 92
*/
If (the plunger 160 is fully retracted into the screw 92)
then {
Pt2 ←Read PT2;
Pt3 ← Read PT3;
Delta23 ← Pt2 − Pt3;
Delta23_Not_Measured ← FALSE;
If (Delta23 >= its corresponding predetermined set point)
then {
/* either plastic viscosity in injection chamber 64 is high,
and/or, plastic is not flowing through injection tube 78 */
Tc2 ← read TC2;
If (Tc2 <= set_pt_hi2) then
Override Process 3, and make sure the heat sources 180
are heating;
}
Until (subcontroller 308 is deactivated).
Note that the variables “Delta 23 ” and “Delta 23 _Not_Measured” have similar meanings as “Delta 12 ” and “Delta 12 _Not_Measured” described hereinabove.
Subsequently, step 424 is performed, wherein the subcontroller 312 is activated for controlling the screw 92 rotation. Pseudo-code describing the actions performed by this subcontroller follow.
Subcontroller 312 processing:
Repeat at predetermined intervals:
If (the input temperature measurements are in the range
[set_pt_low, set_pt_hi])
then
Make screw 92 is rotating Until (PT1 indicates back pressure exceeds
maximum pressure allowed) OR (PT2 indicates pressure from
plastic presence is above a predetermined set point);
If (PT1 indicates back pressure exceeds maximum pressure) then
Stop the screw 92 for an elapsed time “X”, and PT1 pressure
readings are monitored at “X” time intervals. When PT1 drops
below maximum pressure allowed, the screw 92 is rotated;
If (PT2 indicates pressure from plastic presence is above a
predetermined minimum set point) then
The screw 92 is stopped until pressure at PT2 falls below the
predetermined minimum set point for PT2, and PT2 pressure
readings are monitored pressure at “X” time intervals. When PT2
drops below the predetermined minimum set point for PT2, the
screw 92 is rotated;
Until (subcontroller 312 is deactivated).
Subsequently, in step 428 , the expression: (the most recent value of pt 2 by subcontroller 304 is within its corresponding predetermined set point range) AND (the most recent value of Delta 12 computed by subcontroller 304 is within a predetermined set point range) is repeatedly evaluated. When this expression evaluates to “TRUE”, the subcontroller 312 is deactivated and the subcontroller 316 , whose pseudo-code is hereinbelow, is activated.
Subcontroller 316 processing:
Repeat at predetermined intervals:
If ((the most recent value of Pt3 indicates a pressure below its minimum
corresponding predetermined low set point) OR (the most recently
computed value for Delta23 is outside of its predetermined set
point range) then
Make sure screw 92 is rotating;
If (the most recent value of Pt3 indicates pressure exceeds maximum
set point pressure) then
Stop the screw 92 for an elapsed time “X”, and PT1 pressure
readings are monitored at “X” time intervals. When PT1 drops
below maximum pressure allowed, commence rotating the
screw 92;
If (the most recent value of Pt2 indicates pressure is above a
predetermined minimum set point) then
The screw 92 is stopped ”, and PT2 pressure readings are
monitored at ”X” time intervals. When PT2 drops below the
predetermined minimum set point for PT2, commence rotating the
screw 92;
Until (subcontroller 316 is deactivated).
Subsequently, step 440 is performed.
When an appropriate profile is achieved by measurements of the heat source(s) 172 and heat source(s) 180 sequences via their corresponding sensors, we then have a volume of material where the viscosity as measured as resistance to flow, is optimized and known. When this condition is achieved we will have realized a low delta between PT 1 and PT 2 and furthermore a low delta between PT 1 and PT 3 . This allows the use of the screw 92 to extrude plastic directly into the mold 46 when desired.
In any of the following modes of injection molding, operation of the last key component is PT 4 pressure transducer in the injection mold.
The above disclosure lays the foundation for four different injection molding processes: Plastic Injection Molding Method (PIMM) 1 through 4 described hereinbelow.
(a) PIMM1—the Injection Plunger is advanced beyond the truncation of the Lobe Geometry to evacuate the Injection Zone. As the Injection Plunger advances the Nozzle valve is opened to allow flow of plastic into the injection mold causing the mold cavity to fill and plunger travel ceases upon satisfying predetermined pressure set point as indicated by PT 4 . (b) PIMM2—Screw Auger rotates continuously to extrude plastic and the Nozzle valve is opened to allow flow of plastic into the injection mold causing the mold cavity to fill to some predetermined percentage through plastic extrusion (low speed, low shear) when the Injection Plunger is then utilized to finish the injection process to the predetermined pressure set point as indicated by PT 4 at which time plunger travel ceases. (c) PIMM3—Screw Auger rotates continuously to extrude plastic and the Nozzle valve is opened to allow flow of plastic into the injection mold causing the mold cavity to fill completely by extrusion (low speed, low shear) to the predetermined pressure set point as indicated by PT 4 at which time extrusion ceases. (d) PIMM4—Screw Auger rotates continuously to extrude plastic and the Nozzle valve is opened to allow flow of plastic into the injection mold causing the mold cavity to begin filling when the Injection Plunger is then utilized to cycle repeatedly until realizing predetermined pressure set point as indicated by PT 4 at which time plunger travel ceases.
The foregoing discussion of the injection molding system 12 has been presented for purposes of illustration and description. Further, the description is not intended to limit the invention(s) disclosed herein any to the form disclosed. Consequently, variation and modification commiserate with the above teachings, within the skill and knowledge of the relevant art, are within the scope of the present invention. The embodiment described hereinabove is further intended to explain the best mode presently known of practicing the invention, and to enable others skilled in the art to utilize each invention herein, or in other embodiments thereof, and as may be provided with the various modifications required by their particular application or uses of the invention(s) herein.
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A thermoplastic injection molding system and method of use is described for molding parts from heated plastics and other organic resins. The machine uses heat sources located along the barrel to heat the source material while an auger screw transports the source material in the barrel. This transport step does not shear the source material, nor does it use friction to produce the heat necessary to melt the source material. The material becomes substantially liquid or melted during the heating process, and the melted material is forced, by the auger screw, into a chamber whereupon a plunger, situated concentrically with the auger screw, injects the material from the chamber into a mold. Sensors located along the barrel and in the chamber ensure consistency between mold cycles. The controller dynamically adjusts the injection molding process to achieve more consistent and reliable molded parts.
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BACKGROUND OF THE INVENTION
The invention relates to draft power sensors and, more particularly, to draft power sensors which are able to measure the effective draft force and true ground speed of earthmoving equipment and provide a product of the two measurements. The product, called the draft power, is a measure of the power applied to the soil. Maximum production of earthmoving equipment can be achieved if the highest value of draft power is maintained during operation of the equipment.
BRIEF DESCRIPTION OF THE PRIOR ART
The production rate of earthmoving equipment is conventionally measured in cubic yards of soil moved per hour in a particular work situation. The production rate achieved is almost entirely dependent upon the skill of the operator, who must continuously adjust the equipment to maximize the production rate. Production rate for a given type of equipment can be increased by improving the skill of the operator during the dig and transfer processes.
In conventional bulldozing, for example, the operator can only judge production rate in qualitative fashion by sensing forward speed engine lug-down, track slippage, and the quantity of soil being carried by the blade. Human senses are inadequate to combine these inputs into a continuous quantitative measure of production rate that can be sustained for a period of several hours. Also, operator skill varies widely, and the least skilfull operators may move earth at a rate equal to only a small fraction of that of the best operators.
The distance that soil is pushed by a bulldozer has a dramatic effect on the production rate of the equipment. As the distance over which the soil is transferred or pushed is increased, the effective volume of soil moved per unit of time decreases. The density of the soil being transferred also affects the production rate. If the production rate is measured in volume of soil moved per unit of time, the rate will decrease as the density of the soil increases. A more accurate measure of production rate is obtained if it is defined in terms of weight of soil moved per unit of time multiplied by the distance the soil is moved. This method of calculation accounts for the effect of transfer distance and is a measure of the useful rate of work actually achieved.
Only the most experienced operators can attain and maintain high production rates. Less experienced operators will move less soil than the experienced operators because of their inability to accurately judge vehicle speed, the onset of track slippage, and the soil load pushed by the blade. Experience is also necessary to adequately control the blade height in order to doze smoothly and in an optimal manner.
Inexperienced operators may overreach and lower or raise the dozer blade too much and either stall the tractor or doze ineffectively with a small load on the blade. Dozing errors, such as these, will noticeably affect the overall production if allowed to continue. The effects of inexperience upon dozer production are even more pronounced when dozing under poor traction conditions.
The simple slot dozing process can be divided into the dig, transfer and return elements during a typical dozing cycle. During the dig element, the operator loads the blade by lowering the blade into the soil while at normal speed. At this point the force on the dozer blade increases as the soil load builds up in front of the blade. If the blade is lowered too deep, the traction between the tractor tracks and the ground will break, and the forward speed will be significantly reduced. The most productive dig technique involves loading the blade at the optimum rate. This requires the draft force to increase as rapidly as possible while maintaining a relatively high rate of speed. When the blade is fully loaded, the soil is transferred to the desired location. During the transfer element of the cycle, a small amount of soil is dug up to make up for the soil rolling off each side of the blade, creating two windrows. The draft force, during the transfer process, is due to blade shear forces of digging and the frictional resistance of the soil being pushed against the blade. The operator normally adjusts the blade position slightly in order to maintain the full blade load and transfer the load as rapidly as possible. The draft force influences the vehicle speed significantly when dozing at high loads. Therefore, the adjustment of blade position affects both draft force and speed. Efficient soil movement requires good judgment of vehicle speed, which is not measured on dozers, and of blade load, which cannot be seen by the operator. The only way an operator can judge the blade load is by observing the size of the windrow coming off the side of the blade. After the soil is placed in the desired location, the operator backs the tractor to a new starting position during the return element, and digs a new load of dirt to begin a new cycle. Operator skill is also required for achieving a smoother dozer cut as opposed to a rough, rolling cut. A smooth cut results in better traction and less wear and tear on both operator and machine when backing over the cut on the return.
A limited amount of prior work has been accomplished in the general field of controlling earthmoving equipment. The Naval Civil Engineering Laboratory at Pt. Hueneme, Calif., has recently developed a laser-controlled earthmoving equipment system to help dozers, scrapers, and graders hold grade. An explanation of the objectives and methods used is reported in "New Tricks for the Seabee Bulldozer," Navy Civil Engineer, Fall 1974, p. 42. A feature of this system is an engine speed sensor that controls cutting blade height. No means are provided to measure true ground speed, and the blade height control is primarily a method to prevent engine stall-out.
The Army investigated a dozer control in the mid-60's that purported to allow automatic high-speed dozing. The research effort was reported by E. T. Small in "Tractor Earth Blading at High Speeds--Now a Reality," SAE Paper 998B, January 1965. Mechanical devices were provided that allowed for dozer pitch-over after starting a cut to prevent the blade from penetrating too deeply.
Neither of these systems attempted to maximize the power applied to the soil, but instead, they provided means to hold grade while dozing.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a means to quantitatively measure and display production rate of earthmoving equipment.
It is another object of this invention to improve production of earthmoving equipment.
It is a further object of this invention to measure the draft power of earthmoving equipment.
The engine power during earthmoving operations is used to push the soil, slip the tracks or the wheels, overcome friction and accessory power losses, and lift the weight of the equipment on slopes. This relationship is shown in a dimensionless and qualitative form by the following equation:
E=DS+DV+A±V(W sin θ) (1)
where
E=total engine power
D=draft force
S=slip velocity relative to ground
V=true ground speed or vehicle velocity relative to ground
A=friction and accessory power
W=gross vehicle weight
θ=angle of slope, positive upward
The rate of actual useful work being done in moving soil is expressed in the term (DV), the product of draft force and true tractor speed and is defined as draft power. When this draft power is maximized, the useful work being done is maximized. Consider first that zero draft force or zero true ground speed produces zero useful work. Between these two extremes there exists a single maximum value of the product of draft force times true ground speed. All of the remaining terms are variable, but for any condition, maximizing the product DV results in a maximum useful work effort. Slip loss will change with soil condition, grade, vehicle weight, and track condition; and it can vary from zero to a value equal to the engine power less accessory losses. To assess the actual work rate of the earthmoving equipment, true ground speed and draft force must be known.
In order for the equipment operator to use these power relations to maximize production, draft power is converted into suitable signals that are displayed on an analog meter readout on the instrument panel, a blinking light, and a sonic indication through earphones or a loudspeaker. High work rates will result in corresponding signals to the operator, both visually and aurally. Consider the simple case where the operator is leveling a worked-over area with a bulldozer. As the tractor starts forward, draft power (DV) is zero, and then, as the blade is lowered and digs into the soil, draft increase and with it, the draft power increases. This fact is communicated to the operator by a faster tone repetition rate in the headset or loudspeaker, faster blinking of the light, and increasing deflection on the draft power meter. As the blade digs deeper, draft force continues to rise, but velocity decreases. Depending on soil type, engine power, and track slip, at some point the tractor is moving at the best true groundspeed commensurate with draft force. This condition corresponds to maximum draft power (DV). Under these conditions, the draft power meter is at its maximum value, the headset tone is keeping at its fastest rate, and the light is blinking at its fastest rate. If the blade is allowed to penetrate even deeper or if the load of material being carried by the blade increases, the actual work being done decreases because true groundspeed begins to fall more rapidly than draft force can increase. This information is immediately presented to the operator by a lowering of the tone rate, a decrease in meter needle deflection, and slower blinking of the light. The operator, by making small adjustments of the blade height, can determine both the direction and the extent of the blade movement necessary to produce maximum draft power.
Next, assume the soil has very poor traction, and the tracks begin to slip badly. Draft power decreases, and the blade is raised in order to decrease draft and reestablish groundspeed by reduction of slip. Even under these poor dozing conditions, the operator can make the best of the situation and produce the most work possible by use of the draft power monitoring system.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view of the draft power sensor system installed on a tractor with a bulldozer. FIG. 2 is a functional block diagram of a draft power sensor system.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, there is shown earthmoving equipment represented generally by reference number 10. The bulldozer blade 12 is attached to each side of the tractor 14 by a pusharm 13. The true groundspeed sensor package 15 and the draft force sensor 18 furnish information to the electronics circuit box 19 where the information is processed to obtain the product DV in equation 1, defined as draft power. The angle of bulldozer blade 12 is controlled by extending or retracting the cylinder 20, and the height of the bulldozer blade is controlled by extending or retracting cylinder 21. The true groundspeed sensor package 15 determines the true groundspeed of the tractor 14 and can also determine if there is a loss of traction between the track 16 and the soil 17.
Referring now to FIG. 2, the detailed operation of the draft power sensor system will be described. Vehicle velocity is sensed by means of determining the doppler shift of a transmitted ultrasonic beam caused by the velocity of the earthmoving equipment. Transmitter 46 generates a nominal 40 kHz signal which drives an ultrasonic transmit transducer 41. The ultrasonic beam emitted by transmit transducer 41 is reflected from the soil 42 and is received by receive transducer 43. The received signal is amplified in preamplifier 44 and then further amplified and synchronously detected in synchronous detector 45. The output of synchronous detector 45 is the difference frequency between the nominal 40 kHz signal transmitted by transmit transducer 41 and the nominal 40 kHz+doppler shift signal received by receive transducer 43. The doppler shift signal is directly proportional to the velocity of the tractor 14 over the soil 17 as shown in FIG. 1. This resulting signal is amplified and band-limited in band pass amplifier 47 and further amplified in buffer amplifier 48. The signal is then fed to pulse generator and integrator 49 which produces a fixed geometry pulse each time the signal has a zero crossing. The resulting train of uniform pulses has a repetition rate corresponding to the frequency of the doppler signal. When the train is integrated, a DC voltage proportional to the vehicle velocity is produced as an output of the pulse generator and integrator 49. This output is referred to as the velocity signal.
Other means such as a spiked fifth wheel in contact with the ground or optical techniques are also feasible means for detecting the true ground speed.
Bulldozer blade draft forces are sensed by a strain gauge rosette 54, mounted in a protected location on the neck of the trunnion ball 52 to which one of the pusharms 51 is mounted. The force generated by the tractor 14 in FIG. 1 is transferred to the blade 12 through the trunnion ball 52. The low level DC signal voltages proportional to the draft force which are generated by strain gauge 54 are fed to strain gauge amplifier 55. The output from strain gauge amplifier 55 is the draft signal. An alternate approach such as hydraulic or direct deflection means can also be used to obtain the draft force.
The velocity signal and the draft signal voltages are multiplied in the single quadrant multiplier 56. The single quadrant multiplier operates as follows: current regulator 57 supplies a fixed charging current to a storage capacitor which charges at a constant rate producing a linear positive going ramp voltage. One section of single quadrant multiplier 56 allows the capacitor to charge at this regulated rate and another section periodically rapidly discharges it to produce a sawtooth voltage waveform. Component values may be selected to obtain a peak sawtooth voltage uniform amplitude of about 10 volts at a nominal frequency of 1000 Hz. The sawtooth voltage waveform is the reference against which the velocity signal voltage is compared to produce a rectangular waveform with positive state time duration proportional to velocity. The positive amplitude of this rectangular waveform is made draft force dependent so that a final signal waveform is produced having an amplitude proportional to draft force and having a mark/space ratio proportional to velocity. The integrated value of the variable rectangular waveform is the product DV in equation 1. The signal voltage DV is buffered by the adjustable dead band amplifier 58 which can be set to eliminate the effects of vibration and other low-level, short-term shocks on the bulldozer blade 12. The waveform of resulting signal voltage DV supplied to the scaling amplifier 59 is smooth and varies in response to the integrated forces rather than in response to the instantaneous forces on the bulldozer blade 12. The scaling amplifier 59 has a variable gain controlled by the tractor operator and is referred to as sensitivity control 60.
The output of scaling amplifier 59 is fed directly to meter driver 61 which furnishes current to drive the front panel meter 62. The tractor operator can observe the draft power on the meter 62. The output from scaling amplifier 59 is also fed to a variable rate audio burst generator 63 which produces short bursts of signals in the audible frequency range. Preferably, the frequency of the bursts is about 400 Hz. The generator 63 produces about one burst per second with zero input voltage from scaling amplifier 59. The burst rate increases to about 10 per second as the input signal from scaling amplifier 59 rises to ten volts. This variable rate signal output from generator 63, which is proportional to DV, is fed to light-emitting diode driver 64 and audio output amplifier 66. Light-emitting diode driver 64 provides power to a light-emitting diode 65 located on the front panel and can be observed by the tractor operator to provide him with an indication of the draft power. Audio output amplifier 66 provides power to a headset 67 which can be worn by the tractor operator to obtain an audible indication of draft power.
All circuitry in the system is powered by single polarity voltage sources derived directly from the 24 VDC electrical system of tractor 12. The 24 VDC voltage is regulated by using integrated circuits 72, 73 and 74 as shown in FIG. 2. The power supply has an on-off switch 71 and is protected by a fuse 70.
Components for the draft power sensor system circuits are off-the-shelf items. Typical integrated circuits such as, for example, Motorola MC 1555U can be used for transmitter 46; MC 1590 for synchronous detector 45; MC 1558U for band pass amplifier 47, buffer amplifier 48, and strain gauge amplifier 55; MC 3301P for pulse generator and integrator 49; MC 3302P for single quadrant multiplier 56, adjustable dead band amplifier 58, scaling amplifier 59, and variable burst rate generator 63; and MC 1723L for integrated circuits 72, 73 and 74. Standard transistors such as, for example, a 2N5163 can be used for preamplifier 44 and current regulator 57. A 2N3391A can be used for meter driver 61; a 2N2222 can be used for light-emitting diode driver 64; and a 2N5191 can be used for audio output amplifier 66. Transmit transducer 41 and receive transducer 42 are also off-the-shelf items and can be, for example, Linden laboratories, Inc., P/N70100 transducers.
The foregoing is directed to the preferred embodiment, but the scope thereof is determined by the claims which follow.
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A draft power sensor is shown which is capable of determining the amount of power being applied to the soil in earthmoving equipment. The effective draft force and the true ground speed of the earthmoving equipment are measured. This information is processed electronically to provide the product of the two values, which is the draft power. Production from earthmoving equipment can be maximized if the highest value of the draft power is maintained.
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BACKGROUND OF THE INVENTION
The present invention relates to paper machines and in particular to a press section for dewatering a web which may be a suitable paper, cardboard, or the equivalent thereof, this press section having at least three consecutive press nips defined by suitable rolls while including a common endless fabric means in the form of a suitable felt or wire which travels through all of the press nips with the web adhering to this common fabric means so as to be conveyed thereby through the three press nips. On the other hand, at least at the first two press nips the web is engaged by an additional fabric means so that a double-felt action is provided at the first two press nips.
In the manufacture of certain types of paper, cardboard, or equivalent products, it is desirable to carry out the dewatering in such a way that the original web dimension, its length among others, is maintained as nearly unchanged as possible.
When manufacturing paper to be used in bags, for example, the paper web formed on a wire section is conveyed through the press section in such a way that an attempt is made to prevent the web from being subjected in the press section to stresses which might result in elongation of the web. The same considerations apply to the manufacture of stretchable types of paper in those instances where the web has been mechanically contracted or shortened prior to the press section.
On the other hand, the press section should be constructed in such a way that when the web travels beyond the press section the web has as uniform a moisture content as possible both in the longitudinal machine direction of the web as well as in the transverse cross-machine direction. Such a requirement with respect to the uniformity of the moisture is encountered, for example, in the manufacture of bag paper, particularly of so-called wet-upset types of paper which are conveyed through a multiple cylinder drying section while applying to the web an absolute minimum of tension as by utilizing so-called slack runs. The same requirement is encountered in the event that the web is treated in a half-wet state in one way or another as by being worked, for example, with press or micro-creping means.
The construction and operation of the press section also influences the quality of the web, for example the quality of the surface of the paper web. If it is possible to carry out the dewatering of the web for the most part by pressing the web in between felts, then it is possible to avoid an increase in the smoothness of the paper surfaces, and such a lack of smoothness is important, for example, in the case of bag paper. In fact, all desired surface characteristics on both surfaces of the web may be efficiently influenced by way of the quality of the felts.
SUMMARY OF THE INVENTION
One of the objects of the present invention is to provide a press section capable of treating a fiber web in such a way that it can be rendered uniformly dry to an extent sufficient to withstand stresses which arise from detaching and transporting the web beyond the press section.
It is also an object of the present invention to provide a press section which will achieve the highest possible dry matter content of the web subsequent to the press section.
More detailed objects of the invention and advantages derived thereby will be apparent from the description which follows.
The objects of the invention are achieved by way of a press section of the invention according to which the fiber web adheres at the first press nip of the press section to a common endless fabric means in the form of a suitable felt or wire which conveys the web through the first press nip and through at least two additional press nips with a complete wet fiber web being formed in advance of the first press nip on a planar wire or other former. At the first two press nips of the press section the web is engaged at its side opposite from the common fabric means by an additional fabric means in the form of a second felt or wire fabric which is common to the first two press nips and which does not engage the web traveling from the first to the second press nip, or in the form of separate endless felts or wire fabrics which are respectively situated at the first and second press nips.
As a result of the features of the present invention the smoothness of the surfaces may be regulated almost exclusively by way of the particular felt or wire fabrics which are utilized.
In the press section of the invention the web is caused to adhere to an endless felt or wire fabric by a conveying the web to the first press nip where such attachment takes place by utilizing a suitable pressure. At the first press nip as well as the subsequent press nips dewatering takes place. The common fabric means which travels through all of the press nips serves to support the web which continuously adheres thereto while traveling through successive nips.
The additional fabric which engages the web at the first press nip is guided away from the web subsequent to the first press nip, and this fabric may again be guided to the second press nip or a further endless fabric means may be utilized for this purpose.
At each of the press nips the structure of the endless fabric means and of the press section, particularly the construction of the press rolls thereof, may be varied with a view to influencing the dewatering quantitatively and also with a view to controlling the direction of dewatering.
The web is subjected to a number of press nips sufficient to achieve a dry matter content which is sufficiently great to enable the web to tolerate, unchanged, the further treatment of the web such as the drying thereof, for example. The number of press nips will be determined by the speed and thickness of the web, the quality of the pulp stock, etc.
The quality of the endless fabrics is utilized to influence not only the dewatering capacity of the press section but also the quality of the web surfaces. The adhering of the web to the endless fabric means through all of the press section treatment is carried out by proper selection of the felt and press structures. It is possible to utilize for the purpose of adhering the web, for example, a press provided with a suction roll.
The water which is removed from the web in the press section may be directed so as to escape through the fabric means as may be desired. At the press section the water departs from the web to enter the felt which is pressed against a roll which is capable of receiving water. Such rolls are, for example, suction rolls, grooved rolls, rolls which may be furnished with a separate fabric wire, rolls having blind holes drilled in the shell thereof, etc. The dewatering takes place from both surfaces of the web in the event that both rolls at a given press nip are suction rolls, for example.
With the press section of the invention the water is predominantly directed into a felt which is detached from the web at the nip where the latter felt engages the web, this arrangement being most favorable with respect to achieving the desired dry matter content of the web. It is possible in this way to avoid subsequent wetting of the web after the latter press nip, and the water quantity which is jointly contained in the fabric and web and traveling to the next press nip will be maintained at an absolute minimum.
Such a solution to the problem is achieved if the fabric which conveys the web from one nip to the next engages a smooth-surface press roll while, on the other hand, the opposite press roll is capable of accepting water, being, for example a suction roll or a grooved roll. With such a construction the fluid pressure will cause the water to be discharged toward the latter water-accepting roll through the interposed fabric which is detached from the web subsequent to the nip where this latter fabric engages the web.
It is possible further to reduce the fluid pressure in the nip by reducing the water content of the additional fabric means which becomes detached from the web subsequent to a given press nip by conveying the latter fabric means to a separate dewatering means. For this latter purpose it is possible to utilize suction or recessed surface press rolls or a so-called felt suction box. Thus the water content of the fabric arriving at a given press nip will be at a minimum.
It is thus understood that the fiber web that travels at the successive nips, with the possible exception of the last nip, travels between fabrics in the form of suitable felt or wire without directly engaging the press rolls themselves. However, at the last press nip the construction may be such that the web can directly engage one of the press rolls at this last press nip.
Commercial press felts or wires always have certain irregularities which affect the operation of the press and the uniformity of the dry matter in the web. Regular transverse or longitudinal moisture content variations are undesirable because they give rise to temperature differences at the surface of the drying cylinders and thus the effect of such variations is undesirably increased. Simultaneous use of several felts of different lengths at a given nip minimizes the possibility for irregular moisture variations to occur.
With the construction of the invention the uniformity of the dry matter is improved by providing an additional wire on endless felt fabric around one or more than one of the press rolls where this latter further fabric is required to pass between the particular press roll and the common fabric means which conveys the web to the successive press nips. This extra fabric means affords the possibility of utilizing at the nip where it is situated high pressing forces which may be up to 200 to 300 kg per cm without incurring any particular detriment in the operation of the press section or the quality of the paper. This particular circumstance becomes even more significant if the trend toward utilizing light-weight felt for web-carrying purposes continues. Such an extra felt is particularly useful at the last press nip if the web remains in contact with a smooth-surface press roll at this last press nip with a view to facilitating handling of waste.
BRIEF DESCRIPTION OF DRAWINGS
The invention is illustrated by example in the accompanying drawings which form part of this application and in which:
FIG. 1 is a schematic elevation illustrating one embodiment of the invention;
FIG.2 is a schematic elevation illustrating another embodiment of the invention;
FIG. 3 is a schematic elevation of a third embodiment of the invention; and
FIG. 4 is a schematic elevation illustrating a part of a press section of the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to FIG. 1, the paper web has been formed in a known way at the wire 1. Thereafter the web is contacted by the endless fabric means 2 in the form of a suitable felt which laps the nip-suction roll 4. As a result of the suction at the roll 4, the web P is detached from the wire 1 and adheres as a result of suction to the outer surface of the felt 2 being carried thereby to the first press nip 6 of the press section illustrated in FIG. 1. This first press nip 6 is defined by the suction roll 4 and a lower pressure roll 5. At this first press nip 6 there is an endless fabric means 3 in the form of a suitable wire or felt, this being a common endless fabric means in that it is common to the several successive press nips of the illustrated press section.
The roll 5 which is situated within the felt 3 is a smooth-surface roll, while the roll 4 which is within the loop of the endless felt 2 is a suction roll, this roll 4 in addition being situated within the loop of a further so-called fabric wire 19 which laps around the suction roll 4 in the manner illustrated in FIG. 1, being situated between the roll 4 and the endless fabric means 2. As a result of this feature the de-watering of the web P at the first press nip 6 toward the felt 2 is enhanced.
At the first press nip 6 the web P becomes attached to the felt 3 as a result of the construction of the press section and the quality of the felts 2 and 3. The web P and the felt 3, adhering to each other, travel together to the second press nip 7 and then beyond the latter to the third press nip 15.
At the second press nip 7 the lower press roll 9 is a suction roll situated within the common fabric means 3 engaging the latter. As a result of the suction applied at the roll 9 the adhering of the web P to the felt 3 is assured. The upper press roll 8 at the second press nip 7, within the loop of the endless felt 2, is a smooth-surfaced roll. Thus at the second press nip 7 with the embodiment of FIG. 1 the web also travels between the felts 2 and 3.
The felt 2 is dried before reaching the second press nip 7, this drying being carried out by way of a felt suction box 10 and/or drying press rolls 12,13 forming the drying press 11, the roll 13 being a suction roll.
Subsequent to the nip 7, the felt 2 is again dried, a felt suction box 14 being provided for this purpose. Thus the felt 2 is dried before returning to the first press nip 6. Thus it will be seen that the structure includes not only the common fabric means 3 but the additional fabric means 2 which engages the web at the first and second press nips while being guided away from the web to remain out of contact therewith as the web travels from the first to the second press nip.
At the third press nip 15 the lower roll 17 is a roll having a recessed surface, being situated within the loop of the common fabric means 3, this roll 17 being a grooved roll or a Venta-Nip roll. The upper press roll 16 at the last press nip is a smooth-surfaced roll, and the web P travels at this last press nip 15 between felt 3 and the roll 16, adhering to the latter subsequent to the third press nip. Between the first press nip 6 and the last press nip 15 there may be additional intermediate press nips 7. The roll 16 is cleaned by the doctor 18, and subsequent to the roll 16 the web P is guided as illustrated to the drying section while the endless common fabric means 3 is returned to the first press nip.
With the embodiment of FIG. 2 the travel of the web P to the press section is similar to the arrangement of FIG. 1. Thus in FIG. 2 also the web P adheres to the common endless fabric means 3 which conveys the web to the successive press nips of the press section. The first press nip 6 of FIG. 2 has a suction press nip where water travels from the web to the suction roll 4. In the embodiment of FIG. 2 the additional fabric means, instead of including a single endless felt or wire which is common to the first and second press nips, includes only the single endless fabric means 2 which travels only to the first press nip in the manner illustrated in FIG. 2. This endless fabric means 2 of FIG. 2, in the form of a suitable fabric or wire, is dried by the felt suction box 10.
At the second press nip in FIG. 2 there is a recessed or grooved roll 8 toward which the water escapes, the lower press roll 9 at the second press nip 7 of FIG. 2 being a smooth-surfaced roll. The additional endless fabric means of FIG. 2 includes for the second press nip a separate endless fabric means 23 in the form of a suitable felt or wire, this felt or wire 23 being dried by the felt suction box 20 and/or a pair of press rolls 21, one of which at least is a recessed surface roll.
The third press nip 15 of FIG. 2 is identical with that of FIG. 1. Of course in FIG. 2 also there may be additional intermediate press nips 7.
The arrangement illustrated in FIG. 3 is entirely similar to FIG. 2 except that the third press nip 15 in FIG. 3 includes a further endless fabric means 24 in the form of a suitable wire or felt. The lower grooved roll 17 of the third press nip 15 is situated within the loop of the further endless felt 24, pressing the latter against the common endless fabric means 3 with the web being situated between the latter and the roll 16.
Referring now to FIG. 4, by way of example, the intermediate press nip 7 is illustrated therein, this press nip having the upper grooved press roll 8 and the lower smooth-surfaced roll 9. The web P is of course compressed between the common fabric means 3 and the endless fabric 23 in the case of FIG. 4. The roll 8 of FIG. 4 instead of being grooved may be formed with blind drilled holes or other recessed structures.
It will be noted from FIG. 4 that the plane which contains the axes of the rolls 8 and 9 is inclined, having the illustrated angle α with respect to a vertical plane. As a result of this feature the common endless fabric means 3 together with the web P thereon lap the smooth-surfaced roll 9 immediately subsequent to the press nip 7 through a predetermined angle, this being the angle α indicated in FIG. 4. With a view to assuring proper functioning of the press section, this angle α should be at least 5°. In practice an appropriate angle of lap for the angle α will be on the order of 7° to 30°, depending upon the selection of the recessed surface of the upper roll 8. The upper limit of this angle of lap has no significance in practice because the felt 3 and the web P adhering thereto must be carried to the next press nip, so that it is clearly advantageous to utilize a relatively small extent of the lap, yet one which assures the continuous adherance of the web P to the common endless fabric means 3. If, however, this lap angle is less than 5°, then a positive adhering of the web P to the fabric 3 is no longer assured.
The operating conditions prevailing in the machine which manufactures the web will determine the number of nips required and the particular construction thereof as well as the number of felt drying units and felt suction boxes.
The advantages of the press section of the invention are believed to be clear. The wet fiber web which has been separately formed on a planar wire or in another type of former and which has been upset or creped before reaching the first press nip in the press section of the invention is capable of being conveyed through the entire press section in a reliable fail-safe manner without elongation of the web.
Subsequent to the press section of the invention the extent of dry matter in the web is sufficient for assuring the detaching of the web from the press section and its further transportation in a fully reliable manner. The uniformity of the dry matter in the web is extremely good and it is as independent of the quality of the felts as possible. It is possible to change the surface characteristics of the web by selecting suitable felts.
If desired the press section may be constructed entirely without suction rolls so that the investement costs and operating costs can be reduced. Also, if desired, press rolls with rubber coatings may be totally omitted. Moreover it is possible by utilizing double-felted press nips, shown at the first and second press nips above, at the same time to increase the extent of pressure at the press nips considerably so as to achieve a high dry matter content and a high quality paper.
When manufacturing bag paper on a modern paper machine utilizing the structure of the invention, it has been found that at least three main dewatering press nips are required. By means of these three press nips a high dry matter content on the order of 37 to 38% has been achieved as measured subsequent to the press section. At the same time, the length of the web has been increased, compared to the length thereof measured on the forming wire section, by less then 0.5%, whereas with conventional constructions this elongation is at least four times as great.
The press section of the invention adheres the paper web to the common endless fabric means 3 at the beginning of the press section at the first press nip, and the web is not detached from the common fabric means 3 until the web is in a condition dry enough to tolerate in a fully reliable manner the stresses arising from the detaching operation and from the further transporting of the web, such detachment taking place subsequent to the third press nip at the earliest. At the same time the common endless fabric means 3 and the additional endless fabric means formed either by a single endless felt or wire 2 in the case of FIG. 1 or by a pair of additional felts or wires 2 and 23 results in an arrangement where at the first and second press nips, at least, the web is interposed between a pair of felts.
Only a few embodiments of the invention have been presented above. It will be obvious to those skilled in the art that numerous modifications can be made within the inventive concept defined by the claims which follow.
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A paper machine has a press section for dewatering a web, this press section including at least three consecutive press nips and a common endless fabric, in the form of a suitable wire or felt, traveling through all three press nips for conveying a web consecutively therethrough. At the first two of the three consecutive press nips there is an additional fabric structure in the form of one or two endless fabrics in the form of suitable wires or felts, which engage the web at the first and second press nips at the side of the web opposite from the common fabric. However, the additional fabric structure is spaced from that part of the web which travels from the first to the second press nip.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation application of prior U.S. patent application Ser. No. 10/946,197 filed Sep. 22, 2004, which is a Continuation application of prior U.S. patent application Ser. No. 90/655,403 filed on Sep. 5, 2000 (now U.S. Pat. No. 6,813,506), both of which claim priority under 35 U.S.C. §119 to Korean Application No. 1999/37479 filed on Sep. 3, 1999, whose entire disclosure is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to mobile communication services, and more particularly to a method for transmitting and receiving short message broadcasting services in a code division multiple access communication system.
[0004] 2. Description of the Related Art
[0005] Short Message Service (SMS) procedure for a code division multiple access (CDMA) system includes transmitting broadcast messages from a Short Message Service Center (SMSC) to mobile stations through a base station (BS), and receiving the broadcast messages transmitted from the BS at a mobile station MS. Generally, the BS transmits broadcast messages to a MS through two forward channels, namely a paging channel and a broadcast channel. A MS receiving the SMS chooses the messages from among the transmitted broadcast messages.
[0006] The BS may transmit broadcast messages using one of various transmitting methods such as a multi-slot broadcast transmission, a multi-slot broadcast paging or a periodic broadcast paging. Of these methods, the multi-slot broadcast message transmission is the simplest, causing the least amount of delay in transmission, and is used regardless of whether a periodic broadcast paging transmission is available. In the multi-slot broadcast message transmission, broadcast messages are transmitted from a BS to MSs within the service region of the BS through all slots of a control channel. However, because the broadcast messages are transmitted using all slots of the control channel, an overload of the control channel may occur, thereby impeding transmission of messages other than the broadcast messages.
[0007] On the other hand, the multi-slot broadcast paging is used when the periodic broadcast paging is unavailable. In this method, a general paging message of a relatively small size, which indicates a forthcoming transmission, is first transmitted to MSs through all slots of the control channel before transmitting a broadcast message of a large size.
[0008] However, the periodic broadcast paging is a more efficient method than the multi-slot broadcast transmission as well as the multi-slot broadcast paging methods. In the periodic broadcast paging, a BS gives a notice to MSs of the periodic transmission of broadcast messages before periodically transmitting the broadcast messages. Particularly, a BS first transmits a general page message including a broadcast page information in every first slot of a broadcast cycle. Thereafter, a MS can determine the type and time of the message transmission based on the broadcast page and receive broadcast messages in consecutive slots of the broadcast cycle.
[0009] A detailed explanation of the periodic broadcast paging, which is most commonly used by communication systems including the CDMA, will follow. However, a description of a common control channel will first be provided. The common control channel is a channel used when a BS transmits an overhead information required for the operation of a MS as well as a general paging message for paging a MS.
[0010] Generally, the common control channel is a paging channel or a broadcast channel, but for purposes of explanation, the operation of the common control channel will be discussed with respect to the paging channel. However, such operations can also be performed through a broadcast channel.
[0011] FIG. 1 shows a general configuration of a paging channel for the SMS. As shown in FIG. 1 , a BS loads and transmits broadcast messages in a slot of 80 ms, where each slot recurs in every 2048 slot of the paging channel with respect to the system time. The slot (SLOT_NUM) at which a broadcast message is transmitted can be calculated by Equation 1 below, where ‘t’ represent a system time for each am of the paging channel.
SLOT — NUM=└t/ 4┘ mod 2048 [1]
[0012] A MS remains in a non-active state and becomes active to receive broadcast messages transmitted in the 80 ms slot of the paging channel. Upon receipt of the messages, the MS returns back to the non-active or idle state. The periodic broadcast paging method in the related art will next be discussed with reference to FIG. 2 .
[0013] Referring to FIG. 2 , a BS transmits broadcast page information in every first slot of a broadcast cycle and transmits broadcast messages in subsequent slots of the broadcast cycle to MSs. A MS which is configured to receive SMS broadcast message then receives the broadcast messages based on broadcast page(s) by periodically monitoring every first slot of the broadcast cycle to receive the broadcast page information. Here, the maximum interval of the broadcast cycle (M) can be calculated by Equation 2, where ‘i’ represents a maximum slot cycle index (MAX_SLOT_CYCLE_INDEX) field value of a system parameter message transmitted to a MS through the paging channel.
M= 2 i ×16, 0≦i≦7 [2]
[0014] Accordingly, based upon the broadcast cycle M, a BS transmits broadcast page information through a first slot of a broadcast cycle, where the slot number is calculated by Equation 3 below. In other words, the BS transmits Broadcast Pages 1, 2, and 3 through the first slot a broadcast cycle, which is indicated as ‘0’ in the paging channel shown in FIG. 2 .
└t/4┘ mod M=0 [3]
[0015] Each broadcast page transmitted through the first slot as described above, includes at least one broadcast address (BC_ADDR), where each BC_ADDR includes information regarding a broadcast message. As shown in FIG. 2 , the first broadcast page would include two broadcast addresses corresponding to the first broadcast message in slots 3 and 4 , the second broadcast page would include a broadcast address corresponding to the second broadcast message in slot 6 , and the third broadcast page would include three broadcast addresses corresponding to the third broadcast message in slots 9 .about. 11 . Thus, a BS periodically transmits broadcast page(s) in the first slot and broadcast messages in subsequent slots of the broadcast cycle, after notifying MSs of its broadcast cycle through a system parameter message of the paging channel.
[0016] Here, a broadcast index field (BCAST_INDEX) of an expanded system parameter message is used. Namely, a value of BCAST_INDEX is set as ‘i, (1.ltoreq.i.ltoreq.7)’ when the BS is providing a SMS and ‘0’ otherwise. If the value of the BCAST_INDEX is set as ‘i,’ the broadcast cycle in which the broadcast message is transmitted can be calculated using Equation 4.
B= 2 i ×16, 1≦i≦7 [4]
[0017] After the value of B is obtained by Equation 4, the broadcast message is transmitted by a broadcast cycle of (B+3) and the first slot of the broadcast cycle can be calculated by Equation 5.
└ t/ 4┘ mod M ( B+ 3)=0 [5]
[0018] When broadcast messages are periodically transmitted through a paging channel, a MS must also periodically monitor the assigned paging channel. Thus, a MS receives the transmitted broadcast page(s) from the BS through the first slot of the broadcast cycle and if several broadcast addresses (BC_ADDR) are included in the broadcast page(s), the MS checks the subsequent slots to receive the necessary broadcast message.
[0019] In the CDMA system of the related art for the SMS, the broadcast index field BCAST_INDEX of the expanded sys parameter message is used only to set the state of a broadcast cycle and thus the SMS on or off. As a result, a BS cannot notify MSs that there is no broadcast message transmitted during certain broadcast cycles. Thus, a MS has to periodically monitor the common control channel to receive broadcast messages from a BS. Accordingly, a MS must periodically check the common control channel for at least every 80 ms, even when there are no messages transmitted from a BS. This unnecessarily wastes the power consumption of a MS.
SUMMARY OF THE INVENTION
[0020] Accordingly, an object of the present invention is to solve at least the problems and disadvantages of the related art.
[0021] Another object of the present invention is to provide amore efficient method for transmitting and receiving short broadcast message services in a communication system.
[0022] A further object of the present invention is to provide a method for transmitting and receiving short broadcast message services in a communication system which reduce a battery consumption of a mobile station.
[0023] Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objects and advantages of the invention may be realized and attained as particularly pointed out in the appended claims.
[0024] To achieve the objects and in accordance with the purposes of the invention, as embodied and broadly described herein, a method for transmitting and receiving short broadcast message services in a communication system comprises transmitting a broadcast indicator to notify whether a base station is transmitting a broadcast message to a mobile station; receiving the broadcast indicator by a mobile station; and receiving the broadcast message transmitted from the base station through a common control channel during a broadcast cycle when the broadcast message is transmitted at a predetermined broadcast cycle from the base station using the received broadcast indicator.
[0025] In another embodiment of the present invention, a method for transmitting and receiving short broadcast message services in a communication system comprises transmitting, from a base station to a mobile station, a broadcast indicator through an expanded system parameter message to notify whether the base station is transmitting a current broadcast message; determining, at the mobile station, a broadcast indicator value at an arrival time of the broadcast cycle notified by the base station; periodically checking, at the mobile station, a corresponding common control channel when the current broadcast message will be transmitted; and receiving, at the mobile station, a corresponding broadcast message along with periodically checking the channel totted the broadcast message.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The invention will be described in detail with reference to the following drawings in which like reference numerals refer to like elements wherein:
[0027] FIG. 1 shows a paging channel for a SMS;
[0028] FIG. 2 shows a paging channel to explain a periodic broadcast paging method in the related art
[0029] FIGS. 3 and 4 show a paging channel for a broadcast message transmitting and receiving method according to the present invention;
[0030] FIGS. 5 to 7 show a quick paging channel to explain a SMS according to the present invention; and
[0031] FIG. 8 shows a partial field of an expanded system parameter message according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Generally, the present invention transmits a broadcast indicator to a mobile station through a quick paging channel (QPCH) to notify the MS whether a base station is transmitting a broadcast message through a control channel. As in the related art, the control channel may be either a paging channel or a broadcast channel, but for purposes of explanation, the present invention will be discussed with respect to the paging channel.
[0033] FIG. 3 shows a paging channel for transmitting and receiving SMS according to the present invention. Also, FIG. 4 is an enlarged diagram of the paging channel of FIG. 3 and FIG. 5 shows a configuration of the QPCH to explain the SMS according to the present invention. Namely, the present invention additionally uses a QPCH_BI_SUPPORTED field in an expanded system parameter message. The QPCH_BI_SUPPORTED field is used to notify whether a BS provides a broadcast indicator to a MS.
[0034] Referring to FIG. 3 , as in the CDMA mobile communication system in the related art, a BS loads and transmits broadcast message(s) in the 80 ms slot intervals of a broadcast cycle. However, in the present invention, a broadcast indicator as well as a paging indicator and a configuration change indicator are also periodically transmitted in an 80 ms interval to the MS through the QPCH, before transmitting the broadcast message(s), as shown in FIGS. 4 and 5 . In the preferred embodiment, the indicators are transmitted 100 ms prior to transmitting the broadcast messages.
[0035] As in the related ark the broadcast cycle has a period of 2048 where each slot recurs in every 2048 slot of the paging channel with respect to the system time and the slot number SLOT_NUM in which a broadcast message is transmitted can be calculated by Equation 1. Similarly, a value of the maximum slot cycle index MAX_SLOT_CYCLE_INDEX field of the system parameter message is transmitted to the MS through the paging channel from the BS before periodically transmitting the broadcast message(s) and is used to calculate the maximum broadcast cycle M by Equation 2 above. Accordingly, the BS transmits the broadcast page information through the first slot of the broadcast cycle as calculated by Equation 3 based upon the maximum broadcast cycle M.
[0036] Also, the broadcast page information transmitted through the first slot of the broadcast cycle includes at least one broadcast addresses (BC_ADDR), where a BC_ADDR includes information regarding the broadcast message. Thereafter, the BS periodically transmits broadcast messages in subsequent slots corresponding to the broadcast address(es) in the broadcast cycle.
[0037] Furthermore, as in the related art, a broadcast index field BCAST_INDEX of an expanded system parameter message is used, where a value of BCAST_INDEX is set as ‘i, (1.ltoreq.i.ltoreq.7)’ when a BS provides a SMS and ‘0’ otherwise. If the value of the BCAST_INDEX using 3 bits is set as ‘i,’ the broadcast cycle in which the broadcast message is transmitted can be calculated using Equation 4. After the value of B is obtained by Equation 4, a broadcast message can be transmitted by a broadcast cycle of (B+3) and the first slot of a broadcast cycle can be calculated by Equation 5.
[0038] According to the present invention, however, a BS may provide a broadcast indicator and a QPCH_BI_SUPPORTED field to MSs to notify that the BS is transmitting broadcast message(s). If a BS provides a broadcast indicator to MSs, the QPCH_BI_SUPPORTED of the expanded system parameter message would be set to a value of “1” to notify an existence of a broadcast indicator, and otherwise to a value of “0”. Here, the value of QPCH_BI_SUPPORTED may alternatively be set to “0” to notify the existence of a broadcast indicator and to “1,” otherwise.
[0039] The broadcast indicator which notifies an existence of a broadcast message is included and transmitted through the QPCH, where the QPCH is transmitted 100 ms prior to the transmission of a paging channel slot including a broadcast message. Moreover, the QPCH includes and transmits the paging indicator and a configuration on change indicator as well as the broadcast indicator. Particularly, the broadcast indicator may be inserted and transmitted in a reserved region of the QPCH. A MS then temporarily stores QPCH_BI_SUPPORTED field value of the expanded system parameter message from the BS in a memory device. If a MS in a non-active state is configured to receive a broadcast message, such MS would periodically monitor the first slot of the paging channel in every broadcast cycle.
[0040] However, if the QPCH_BI_SUPPORTED field value of the extended system parameter message is set to ‘1’ and if a MS is configured to receive a broadcast indicator, such MS would check the QPCH transmitted 100 ms before each slot of the paging channel in the broadcast cycle to determine the broadcast indicator value and the BCAST_INDEX value. Thus, if the QPCH_BI_SUPPORTED field value is set to “1” and the broadcast indicator is also set to “1,” a MS would determine that a broadcast page information and broadcast message(s) is transmitted through the paging channel and would monitor the paging channel to receive the necessary messages.
[0041] If the QPCH_BI_SUPPORTED field value is set to “1” while the broadcast indicator is set to “0,” and the BCAST_INDEX value is “0,” then a MS would enter into an idle state without monitoring the paging channel.
[0042] If the “QPCH_BI_SUPPORTED” field value is set to “0,” a MS would periodically monitor the first slot of the paging channel for easy broadcast cycle as in the related art, and would receive the broadcast page information from the BS. Furthermore, if several broadcast addresses (BC_ADDR) are included in the broadest page information, a MS would monitor hew subsequent slots to receive the necessary broadcast message.
[0043] FIG. 6 shows the QPCH of FIG. 5 when the data rate is 4800 bps and FIG. 7 shows the QPCH of FIG. 5 when the data rate is 9600 bps. Namely, FIGS. 6 and 7 show configurations of the QPCH of FIG. 5 in which 1, 2 or 4 bits are used for transmitting the broadcast indicator. However, using 1 bit for the broadcast indicator requires a high power supply. Therefore, by transmitting the broadcast indicator using at least 2 bits, as shown in FIGS. 6 and 7 , lowers the power consumption and reduces an interruption factor.
[0044] FIG. 8 shows a portion of the expanded system parameter message field which additionally includes the QPCH_BI_SUPPORTED field and the broadcast index field (BCAST_INDEX) of 3 bits according to the present invention.
[0045] According to the present transmitting and receiving method of short message broadcast services, the BS notifies to the MS, in advance, whether a transmission of broadcast message currently exists. Therefore, a MS need not unnecessarily and periodically monitor the common control channel (the paging channel or the broadcast channel) to receive a broadcast message from the BS, if there is no broadcast message. Thus, the present invention prevents a waste of power consumption by the MS and increases the efficiency of the short message broadcast services.
[0046] The foregoing embodiments are merely exemplary and are not to be construed as limiting the present invention. The present teachings can be readily applied to other types of apparatuses. The description of the present invention is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art.
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A method for transmitting and receiving short message broadcast services in a communication system is disclosed. The present invention reduces a battery consumption of a mobile station by additionally using an inserted message field of a broadcast indicator for notifying whether a broadcast message is being transmitted from a base station to the MS, thereby allowing a more efficient short message broadcast service.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to ball valves, and more particularly to ball valves having means for equalizing fluid pressure between the flow line and the valve body chamber.
2. Description of the Prior Art
Heretofore, when floating ball valves have been utilized in flow lines having relatively high flow line pressures, it has sometimes been difficult to rotate the ball valve member to a closed position. Annular pressure actuated seats are normally provided on opposite sides of the rotatable ball valve member and a differential fluid pressure area results in the annular seats being forced toward the ball valve member to grip or squeeze the ball valve member tightly therebetween. Because a fluid tight seal is normally provided between the surface of the ball valve member and the annular seats, there is no leakage of fluid from the flow line to the valve chamber in the open and closed positions of the ball valve member.
The higher the flow line pressure, the tighter the annular seals are forced into contact with the ball valve member. Thus, particularly when manually operated under high fluid pressures, such as 4,000 or 5,000 psi, manual rotation of the ball valve member from open position to closed position is very difficult, and practically impossible if relatively large differential fluid pressure areas are provided at very high fluid pressures.
If the flow line and ball valve are used for drilling mud in a drilling operation, such as a kelly or downhole valve, very high backflow pressures can result from a blowout or the like. For safety reasons, it is desirable that a ball valve can be easily rotated manually to a closed position under the application of very high fluid pressure.
When used as a kelly valve, a ball valve in the closed position may have extremely high pressure applied to the bottom side of the ball. Prior art ball valves have been extremely difficult to open for pressure control procedures due to the bottom side pressure acting to pinch the valve seats against the ball.
SUMMARY OF THE INVENTION
This invention concerns a ball valve having a floating ball valve member and fluid pressure actuated annular seal members engaging the floating ball valve member. The ball valve member is mounted within a valve chamber in the valve body for a quarter turn rotation of 90° between open and closed positions. The fluid pressure in the body chamber acts against the annular seal members in a direction opposite the flow line pressure. If fluid pressure in the body chamber is equalized with the flow line fluid pressure, the sealing members are pressure balanced and are forced by spring members into sealing engagement with the ball valve member. Thus, the ball valve member may be easily rotated manually between open and closed positions.
The present invention relates to a ball valve having a stop to limit the rotation of the ball valve member to a quarter turn or 90° for movement between fully open and fully closed positions of the ball valve member relative to the flow line passage.
The ball valve member has a central bore through it. A pressure equalizing opening or hole extends from the central bore through the body of the ball valve. Such hole is provided in the quadrant of the ball valve member exposed to upstream fluid pressure in the closed position so that upstream fluid pressure is in fluid communication with the valve chamber through the bore of the ball valve member.
When the ball valve member is in the open position, flow line pressure is communicated through the pressure equalizing opening to the ball valve chamber. Accordingly, when the ball valve member is in open position, fluid pressure acting against the annular seal member is balanced or substantially balanced to permit the ball valve member to be rotated manually, even at very high fluid pressures, such as 4,000 psi. In the closed position, a fluid pressure may be applied from the upstream side of the closed ball valve member to offset the downstream fluid pressure and permit manual opening of the ball valve member even at extremely high downstream fluid pressures.
It is an object of this present invention to provide a ball valve having a ball valve member mounted for rotation between open and closed positions and having means to equalize the fluid pressure between the flow line passage and the valve chamber to permit manual rotation of the ball valve member to the closed position, even at high flow line pressures.
It is a further object of this invention to provide such a ball valve in which fluid balancing means are provided for the closed position of the ball valve member to permit manual rotation of the ball valve member to an open position upon the application of a high upstream fluid pressure even at a high downstream fluid pressure.
Other objects, features, and advantages of this invention will become more apparent after referring to the following specification and drawing.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of the ball valve of the invention showing the ball valve member in an open position; and
FIG. 2 is a sectional view of the ball valve of FIG. 1 but showing the ball valve member in a closed position and engaged by a manual wrench for manual rotation of the ball valve member between open and closed positions.
DESCRIPTION OF THE INVENTION
Referring now to the drawings the present invention is shown used as a lower kelly valve. A kelly is the drive connection between a drill string and surface drilling equipment for rotation of the drill string. Kelly valves are generally placed above and below the kelly to provide pressure protection for the kelly and surface equipment. When a high pressure "kick" of subsurface gas enters the drill string, it is necessary to manually turn the kelly valve to a closed position for the protection of the surface equipment.
The lower kelly valve comprises a ball valve shown generally at 10. A lower sub or housing 12 receives an upper sub or housing 14 threaded to each other at 16. A lower downstream flow line passage 18 is formed by lower sub 12 and an upper upstream flow line passage 20 is formed by upper sub 14. Lower housing 12 has an annular groove or pocket 22 receiving a downstream annular seat 24 forced outwardly by a Belleville spring 26. Upper housing 14 has an annular groove or pocket 28 which receives an upstream annular seat 30 forced outwardly by Belleville spring 32. Annular resilient seals 34 seal about the outer periphery of annular seats 24 and 30 and annular face seals 36 extend about the inner faces of seats 24 and 30 for sealing against ball 40.
An enlarged annular valve chamber 38 is defined by housing 12. A ball valve member generally indicated at 40 is mounted within chamber 38 for rotation within chamber 38. Ball valve member 40 has a generally spherical body with a central bore 42 through it forming a flow passage in line with flow passages 18 and 20. Bore 42 has the same diameter as flow passages 18 and 20.
An outer surface of ball valve member 40 has an elongate slot 44 extending at right angles to the longitudinal axis of bore 42 when the valve is in the open position. Such slot is in a direction parallel to the longitudinal axis of flow passages 18 and 20 when the valve is in the closed position of ball valve member 40.
A stem generally indicated at 46 fits within an opening 48 in lower housing 12 and has a rectangular lug 50 fitting within slot 44. A flat sided opening 52 in stem 46 is adapted to receive the extending end of a wrench 54 for manual rotation of ball valve member 40 between open (FIG. 1) and closed (FIG. 2) positions. The outer surface of ball valve member 40 has an arcuate groove 56 in it which receives a stop 58 secured to housing 12 for limiting rotation of ball valve member 40 to a quarter turn or 90°.
As shown by dimensions A1 and A2, a fluid pressure differential area exists between the area indicated at A1 acting to force seats 24 and 30 against ball valve member 40 and the area indicated at A2 acting to force seats 24 and 30 away from ball valve member 40. When a high flow line pressure is applied against seats 24 and 30 in the open position shown in FIG. 1, seats 24 and 30 will be forced tightly against the outer surface of ball valve member 40 to make it difficult to rotate ball valve member 40 to a closed position.
In the closed position of ball valve member 40 as shown in FIG. 2, seat 24 will be forced tightly against ball valve member 40 from the downstream high fluid pressure in passage 18. The fluid pressure in chamber 38 is normally substantially less than the flow line pressure because seals 34 and 36 prevent or minimize any leakage of fluid to the body chamber 38 from passages 18 and 20.
To equalize or substantially equalize the fluid pressure acting on the opposed faces of seats 24 and 30, a small fluid equalizing opening hole or port 60 of about 1/8 inch in diameter extends from bore 42 through the body portion of ball valve member 40 which is exposed to fluid pressure from the upstream flow passage in the closed position of the ball valve member 40. The outer surface or quadrant 62 of ball valve member 40 circumscribed by or within the confines of seat 30 as shown in FIG. 2 is exposed to fluid pressure from upstream flow passage 20.
In the open position of ball valve member 40 shown in FIG. 1, flow line pressure is communicated through opening 60 to valve chamber 38 to act against the faces of seats 24 and 30 exposed to fluid pressure from chamber 38 thereby to equalize the pressure acting on seats 24 and 30.
In the closed position of FIG. 2 in which the downstream or bore hole pressure is controlled by ball valve 10, a suitable flapper check valve (not shown) may be installed upstream of upper sub 14. Fluid can be pumped downwardly by surface equipment through such check valve and against ball valve member 40. Fluid passes through opening 60 to valve chamber 38 for acting against face 63 of downstream seat 24 exposed to fluid pressure from chamber 38 to permit ball valve member 40 to be easily rotated to an open position.
Ball valve 10 may be easily assembled by first inserting spring 26 and seat 24 within pocket 22. Stem 46 with lug 50 is then inserted within opening 48. Ball valve member 40 is inserted with lug 50 being received within slot 44. In this position, upper housing 14 with spring 32 and seat 30 inserted in pocket 28 is threaded within lower housing 12.
While a preferred embodiment of the present invention has been illustrated, it is apparent that modifications and adaptations of the preferred embodiment will occur to those skilled in the art. However, it is to be expressly understood that such modifications an adaptations are within the spirit and scope of the present invention as set forth in the following claims.
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A kelly valve includes a ball valve structure (10) having a ball valve member (40) with a central bore (42) therethrough mounted within a valve chamber (38) for rotation between open and closed positions. A fluid pressure equalizing opening or port (60) is provided in the quadrant of the ball valve member (40) exposed to the upstream flow passage (20) in closed position (FIG. 2) and exposed to the valve chamber (38) in open position (FIG. 1) thereby making the ball valve member (40) easy to rotate manually even at high downstream fluid pressures.
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CLAIM OF PRIORITY
[0001] This application claims the benefit of U.S. Application No. 60/607,331 filed Sep. 03, 2004, which is incorporated herein in its entirety by reference.
BACKGROUND
[0002] 1. Field of the Invention
[0003] The invention relates to the testing and manufacturing of thin film materials. More specifically, the invention relates to thermal diagnostics for finding defects and/or measuring or identifying features of integrated circuits.
[0004] 2. Background of the Invention
[0005] A variety of scanning thermal probes have been developed for mapping spatial variations in surface temperatures or the thermal properties of samples. The transducing elements for such devices have included thermocouples, Schottky diodes, bolometer-type resistance change devices, and bimorphs. A bolometer-type sensing element, which maps temperature by fractional changes in electrical resistance, has certain advantages for microcalorimetry applications. In particular, the resistor in the probe can be used to supply heat if sufficient current is passed through it. Because the tip temperature is ultimately influenced by the heat flow between the tip and the sample, variations in thermal conductance across the sample can be mapped by such a probe. If the heat is supplied by a periodic signal, local variations in thermal capacity can also be measured. In essence, because the probe tip serves as a point source of heat as well as a temperature sensor, such devices can be used as a spatially localized microcalorimeter. See A. Hammiche, et al., J. Vac. Sci. Technol. B, Vol. 14, 1996, pp. 1486, et seq.; L. E. Ocola, et al., Apl. Phys. Lett., Vol. 68, 1996, pp. 717, et seq.; D. Fryer, et al., Proc. SPIE, Vol. 333, 1998, pp. 1031, et seq.
[0006] While microcalorimetry techniques that use thermal probes for characterization of materials have been reported, they have failed to anticipate recent developments in both probe technology and rapidly evolving application areas. For example, past efforts in using thermally sensitive probes for microcalorimetry were focused on single point measurements that were made with either wire-based probes that were fabricated by non-lithographic means, or on lithographically micromachined single probes that were not appropriate for high-throughput measurements. In recent years, efforts at developing thermal probes using polyimide as the structural material have led to highly compliant devices that can be operated in contact with the sample surface without force feedback, even for relatively soft samples. In addition, the use of lithographic fabrication methods has permitted the integration of more sophisticated functionality than afforded by a single thermal sensor, and the development of more complex structures than a single cantilever or loop. In general, the thermal, mechanical, and electrical properties of the scanning microstructures can all be optimized for the particular application at hand. This evolution in microstructure technology has also opened up the possibility of using new sensing methods. For example, it is possible to stimulate a sample using one part or element of a probe-like microstructure, while the sensing is performed by a different part in the same structure or potentially even a separate microstructure that is coupled to the first in a pre-determined manner. As a further example, the nature of the electrical and thermal waveforms that may be used with these structures is more diverse than the time-invariant (fixed value) and the oscillatory waveforms that have been anticipated in the past. Thus, impulse-type waveforms that are not periodic may be used to determine the properties of a pixel or the simultaneous characterization of multiple disparate pixels. More complex waveforms are also anticipated. In addition, the potential application arenas for these systems have also changed. Several emerging needs for scanning thermal diagnostics in the semiconductor industry have not been anticipated or addressed in the past. These applications, which typically require high speed mapping of relatively large areas, and may sometimes require only qualitative comparisons, potentially include: the detection of spatially distributed defects in thin films such as sub-surface voids in interconnect metal or defects in the bond interface between two structures or materials; the characterization of process steps such as mapping the distribution of implanted dopant concentration or thickness variation in deposited films; and the correlation and comparison of simultaneously acquired high resolution images of temperature in an operating circuit or the observation of their temporal changes to predict or diagnose reliability. These various shortcomings in existing and previously anticipated know-how are addressed by the systems and methods that are described in this document.
[0007] The measurement of sub-surface areas with high speed, high spatial resolution and in a non-destructive manner is a significant challenge in semiconductor process monitoring. Voids in semiconductor surfaces arise to non-idealities in the deposition process. For example, voids may occur in thin film copper interconnects due to non-uniformities in deposition rates related to variations in topography or the proximity and size of features. It is not always possible to detect these defects before the completion of the manufacturing process, and they can potentially make their way into the final device or system, leading to long term reliability problems that are very expensive to detect and correct. Present options for detecting these defects include systems using: laser-induced surface acoustic waves, which have a resolution that exceeds 10 microns and so can only determine large clusters of defects; acoustic microscopy, which offers better resolution but can require the sample to be immersed in a liquid; point-by-point electrical testing, which lacks the necessary throughput to be practical in a production setting; and scanning electron microscopy, which requires the sample to be sectioned, and is accordingly both slow and destructive. These and other inadequacies of the prior art are addressed by this invention.
[0008] Dopant mapping in semiconductors is commonly performed by measuring the change in reflectance when the semiconductor is heated with a laser. For a given laser power output, the final temperature of the semiconductor depends upon the thermal conductivity, which corresponds to the dopant concentration. See A. Rosencwaig, Thermal Wave Characterization and Inspection of Semiconductor Materials and Devices, Ch. 5 in Photoacoustic and Thermal Wave Phenomena in Semiconductors, ed. by A. Mandelis (Elsevier Science Publishing, New York, 1987). Systems and methods based on scanning thermal microstructures potentially provide high resolution non-destructive alternatives to existing approaches and may even be used as complementary methods.
[0009] The thickness of a thin film on a substrate may be measured using photoacoustic methods. In this procedure, the sample is enclosed within a sealed container and illuminated with a laser through a variable speed optical chopper. The sample is heated by the chopped laser signal, causing the surrounding air to heat. The resulting increase in air pressure is measured. By varying the chopper frequency, the thickness of the thin film may be determined. See D. Almond, Photothermal science and techniques (Chapman and Hall, London) 1996. For this application as well, scanning thermal microstructures potentially provide high resolution non-destructive alternatives to existing approaches.
SUMMARY OF THE INVENTION
[0010] The invention includes systems and methods for scanning a thermal probe in the vicinity of a sample material, such as a semiconductor material, applying stimuli to a thermal probe in proximity to the sample, and monitoring the interaction of the thermal probe and the sample. The stimulus can be applied by a variety of methods, including Joule heating of a resistor in the proximity of the probe tip, or optically heating a tip of the thermal probe using a laser. In embodiments of the invention, the interaction may be detected by measuring the time-dependent voltage and current through a resistor in the proximity of the probe tip, whose properties vary depending upon the stimulus applied and the interaction of the probe with the sample.
[0011] Defects in integrated circuits may be identified by observing the heat flow from a tip of the probe to the integrated circuit. A defect can cause a different rate of heat flow by impeding or aiding in the heat transport through the integrated circuit. Furthermore, defects can affect the transient heat flow from the probe to the integrated circuit by altering the effective specific heat of the integrated circuit. In embodiments of the invention, voids may be detected within copper interconnects within integrated circuits. In some such embodiments, these voids may be detected by a higher heat flow rate observed initially after a thermal stimulus is applied, or from a lower heat flow rate observed after some time.
[0012] Embodiments of the invention may be used to identify the number of dopant atoms in the semiconductor after steps such as ion implantation. In some such embodiments, the number of dopant atoms may be found from the dependence of dopant atom concentration versus heat flow rate. The higher the dopant atom concentration, the lower the heat flow rate in a semiconductor such as silicon.
[0013] By applying a periodic thermal stimulus to the top of a thin film on sample material, such as an integrated circuit, embodiments of the invention may be used to measure the thickness of a film. In some embodiments, the interaction between the thermal probe and the sample depends upon the thickness of the thin film, permitting the thickness to be measured through a response of such interaction.
[0014] Embodiments of the invention may identify the localized temperature of an integrated circuit; such temperatures may be indicative of the performance of the integrated circuit. A locally hot region (“hot spot”) on an integrated circuit may be indicative of a point that has failed or is likely to fail. Embodiments of the invention use a bolometer in the vicinity of the probe tip and apply a brief stimulus to the bolometer to permit a localized temperature measurement to be performed. In some such embodiments, the stimulus may subsequently removed to minimize self-heating of the thermal probe, and allow the temperature of the bolometer to reach equilibrium with the sample before another measurement is performed.
[0015] These and other objects of the present invention are described in greater detail in the detailed description of the invention, the appended drawings, and the attached claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a schematic of a thermal probe, in accordance with embodiments of the invention.
[0017] FIG. 2A -B shows schematic diagrams of the components of two exemplary scanning probe microscopes, one with and one without a mechanical z-axis feedback loop, in accordance with embodiments of the invention.
[0018] FIG. 3 schematically illustrates an example of a void defect in metal on an integrated circuit.
[0019] FIG. 4 presents an illustrative example of a change in thermal conductivity due to a void in copper interconnect.
[0020] FIG. 5 illustrates an example of a time taken to heat a line of copper interconnect in an integrated circuit when a constant temperature is applied to the top surface of the integrated circuit.
[0021] FIG. 6A -B illustrates examples of the magnitude and phase of heat flow from a thermal probe as a function of frequency for (A) 200 nm thick and (B) 1 nm thick silicon dioxide on a silicon substrate.
[0022] FIG. 7 illustrates an analogy between different layers of material and an electrical transmission line, in accordance with embodiments of the invention.
[0023] FIG. 8 illustrates a timing waveform for a method for reading the temperature of a bolometer thermal probe with a large current without significantly raising the probe temperature, in accordance with embodiments of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0000] A. Introduction
[0024] The invention pertains to the application of a stimulus to a scanning thermal probe and the detection of the thermal interaction between the probe and a sample. Embodiments of the invention may involve the use of one or more of the following techniques:
(a) Observation of the frequency response of probes in proximity to the sample. The relevant observables may include one or more of the following: the difference in phase between the applied stimulus and response, the frequencies of the maxima and minima of the phase difference, the amplitude degradation with frequency, and/or the step response. (b) Observation of the DC response of probes in proximity of the sample. (c) Application of a periodic sampling algorithm, whereby a stimulus is applied to a thermal probe for a duration of time smaller than the thermal time constant of the probe, thereby minimizing heating of the thermal probe. In embodiments of the invention, this sampling algorithm may be used in conjunction with multiple probes connected to a single interface circuit through a multiplexer.
[0028] In some embodiments, one or more of these techniques may be applied simultaneously. Furthermore, the invention also pertains to methods of using the scanning thermal probe to sense thermal properties and events within a sample without the use of a stimulus.
[0000] B. Implementation of Thermal Probes
[0029] In embodiments of the invention, the thermal probe used in diagnoses of a material sample may be stimulated electrically or with a light source, such as a laser. The thermal probe then induces an effect on the sample, such as adding heat to the sample, heating the sample to a set temperature, introducing an evanescent wave, or introducing a thermo-acoustic wave; other effects that may be induced on the sample shall be apparent to those skilled in the art. The effects of this interaction on the thermal probe are subsequently measured.
[0030] The thermal probe can be biased at a temperature and a sinusoidal (or other periodic waveform) applied to the thermal probe. In embodiments of the invention, the temperature of the probe may be measured; alternatively a heat flow which maintains the probe at a constant temperature may be measured. As the frequency is swept, the amplitude or phase is measured. The rate of amplitude roll-off, the phase difference, or the location of the phase maxima and minima may be used to discern properties of the sample.
[0031] In embodiments of the invention, a step in temperature or heat flow may be applied to the thermal probe and the time response of the thermal probe may be measured. In alternative embodiments, a constant temperature or constant heat flow may be applied to the thermal probe and the interaction between the thermal probe and the sample may be measured in response.
[0032] In embodiments of the invention, the thermal probe may be passively coupled to the sample and the probe temperature measured in response. Such embodiments allow the probe to be used to measure the localized temperature of the sample, heat flow from another portion of the sample, or a thermal wave from another portion of the sample.
[0033] In embodiments of the invention, the thermal probe may be stimulated for a very brief duration of time. If the duration is smaller than the thermal time constant of the thermal probe, the temperature of the thermal probe will not be significantly affected. This feature can be used to send a large current pulse through the probe, measure the voltage drop, and thus determine the probe resistance without significant heating occurring.
[0034] In embodiments of the invention, defects in a sample, such as an integrated circuit, are found by scanning the probe across the sample and measuring the thermal conductance or thermal capacitance as a function of position. A defect will be manifested as a region with a different thermal conductance or thermal capacitance from that which was expected. The presence of the defect can be deduced by observing the difference in thermal conductance or thermal capacitance between a reference region of the sample and the region with the defect; alternatively the defect can be found by observing a different thermal conductance or thermal capacitance in comparison to a “golden standard,” i.e., a sample that is known to be free of defects.
[0035] A thermal probe used by embodiments of the invention is illustrated in FIG. 1 . A sensor is located at the end of a cantilever. The thermal probe, or an array of probes, is scanned across a sample, in a manner similar to an atomic force microscope (AFM). At every location of interest, the electrical properties of the thermal probe are measured, representative of the interaction between the sample and thermal probe as a non-limiting embodiment. One mode of operation is to scan the thermal probe over an area to obtain an image of the area of interest on the sample. A second method is to scan the thermal probe in a line, crossing features of interest. A third method is to move the thermal probe to a single or multiple locations of interest and perform a detailed analysis at those locations.
[0036] FIGS. 2A and 2B schematically illustrate embodiments of the invention with and without Z-axis feedback, respectively. Z-axis feedback 200 provides the ability to maintain a constant force between the probe and sample, thereby lowering the noise level. But operation without z-axis feedback 202 permits lower cost and a much easier implementation of an array of thermal probes. Embodiments of the invention employ control to maintain proper contact between the probe and sample flexible cantilever that allows the choice of whether to use z-axis feedback.
[0037] In some embodiments of the invention, a temperature sensor such as a thermocouple or a bolometer is located at the thermal probe tip. The thermocouple is well suited for applications where the probe tip is not thermally biased and temperature is measured. The bolometer is well suited for applications where the probe tip must be heated to a desired temperature and the heat transfer from probe tip to sample is monitored.
[0000] C. Examples of the Application of Thermal Probe
[0038] Some of the applications of these methods include (a) finding defects on integrated circuits, such as mapping voids in copper interconnects and mapping damage due to ion implantation (b) mapping the quantity of dopant atoms in a semiconductor, (c) finding the thickness of thin films, and (d) mapping the temperature of an integrated circuit. These applications are further described herein, and other applications of the techniques described herein shall be readily apparent to those skilled in the art.
[0039] (1) Detecting Voids in a Metal Interconnected on an Integrated Circuit Using Changes in Thermal Conductance
[0040] Voids within an integrated circuit metallization layer are one type of defect that can be detected with the scanning thermal microscope. FIG. 3 schematically illustrates a structure of an integrated circuit 300 with a void 302 in the metal. Conventionally, during the manufacture of integrated circuits with copper interconnects, the copper is deposited using electroplating from the sidewalls of a trench. In the vicinity where the two copper surfaces meet, a seam is formed and very often voids are also formed due to irregularities in the manufacturing process. These voids affect the electrical performance and reliability of the integrated circuit, and merit detection as a consequence. The voids in the copper are typically filled with copper electroplating solution, which has a thermal conductance of approximately 1.6 W/mK, which is significantly lower than the thermal conductivity of copper, 400 W/mK. Thus, measuring the thermal conductance is an effective method of both locating the voids within copper, and obtaining information on the size of the voids. As a non-limiting, illustrative example, a simulated result of a structure whose dimensions are typical of those found in a 130 nm integrated circuit manufacturing process is shown in FIG. 4 , where it is seen that the change in thermal conductance depends upon the void depth and size; this dependency allow defects in the integrated circuit to be classified by these parameters.
[0041] (2) Detecting Copper Voids from the Step Response
[0042] Voids within copper may be found from the time-based thermal response 500 . A temperature pulse (or other thermal stimulus) is applied to the copper structure and the heat flow 502 is measured as a function of time 504 . The measured heat flow depends upon the thermal properties of the material in the vicinity of the thermal probe. A void in the copper will slow the thermal interaction between the probe and sample, as illustrated in FIG. 5 . FIG. 5 shows a simulation of the difference in heat flow versus time for a solid copper line on an integrated circuit and for a copper line with a void in it; the example depicted in FIG. 5 is for illustrative purposes only, and is not intended in any way to limit the scope of the invention.
[0043] (3) Detecting Lattice Damage in a Semiconductor
[0044] A defect in a crystal lattice introduces a scattering site for phonons. The defects therefore affect the heat flux in semiconductors. Thus, damage in a semiconductor can be discerned by the changes in the thermal conductance. Ion implantation is a manufacturing technique that introduces significant crystalline damage to the silicon structure. By comparing the thermal conductivity of the sample with the thermal conductivity of a similar defect-free semiconductor, the degree of damage may be determined.
[0045] (4) Mapping Dopant Concentration in a Semiconductor
[0046] Ion implantation introduces dopant atoms to a semiconductor. The wafer is then annealed to significantly reduce the implant damage. The dopant atoms that are introduced to the silicon lattice introduce scattering sites for phonons, and thus decrease the thermal conductivity of a semiconductor. By comparing the thermal conductivity of the sample with the thermal conductivity of known dopant concentration, the dopant concentration may be determined.
[0047] (5) Measuring the Thickness of a Thin Film
[0048] By applying a periodic temperature waveform to the thermal probe tip, a thermal evanescent wave may be generated at the top surface of the sample. This evanescent wave propagates down through the sample, and any change in thermal diffusitivity will generate a reflected wave back towards the surface. In such a manner, constructive and destructive interference effects may be observed, analogous to the interference effects observed optically in thin films. This phenomenon can be used to find the thickness of thin films, whether they are transparent or opaque.
[0049] In other embodiments, the thickness of a thin film can be found from alternative techniques, including (1) a plot of the magnitude of heat flow versus frequency, and/or (2) from a plot of the phase of heat flow versus frequency. FIG. 6 illustrates a simulation result for a thin layer of silicon dioxide on top of a thick silicon substrate 604 . As shown in the top plots of FIGS. 6A and 6B , the magnitude of heat flow 602 is distinctly different for the two thickness of silicon dioxide 606 608 . As shown in the bottom plots of FIGS. 6A and 6B , the phase of heat flow is different for the two thicknesses, having maxima 610 612 and minima 614 616 at distinct frequencies that are thickness dependent.
[0050] The path for heat flow is analogous to an electrical transmission line. In embodiments of the invention, the magnitude and phase of the heat flow are calculated analogously by using two or more electrical transmission lines in series, as shown in FIG. 7 . Each material 702 704 is represented by a transmission line whose resistance and capacitance are calculated from the relatcor:
R = 1 σ th A
C=C p ρA
where σ th is the thermal conductivity of the material, A is the probe area, C p is the specific heat of the material, and ρ is the density of the material. The length of each transmission line is the physical thickness of the layer.
[0051] (6) Temperature Mapping
[0052] Temperature mapping is performed by scanning a thermal probe across the sample surface and measuring the temperature at every location. This technique has several advantages over infrared (IR) imaging. First, it has a much higher spatial resolution, better than 50 nm, than can be achieved with IR. Second, calibration is easier because it is not necessary to know the material properties a priori, by contrast with IR.
[0053] For a thermal probe with a bolometer as the sense element, embodiments of the invention perform temperature mapping by using a small current to prevent the temperature rise due to the current from significantly affecting the measurement. An alternative method used in embodiments of the invention measures the temperature using a bolometer by passing a large current through the bolometer for a very short period of time and measuring the voltage across the bolometer measured during this time. If the current pulse is significantly shorter in duration than the thermal time constant of the thermal probe, the temperature of the thermal probe will not appreciable increase and an accurate temperature may be measured. In some such embodiments, the measurement is not repeated until a period of time passes that is substantially as long as the thermal time constant of the thermal probe. This permits the thermal probe to achieve thermal equilibrium with the sample. A non-limiting, illustrative example of a waveform 800 demonstrating this procedure is given in FIG. 8 . The temperature at each thermal probe in an array can be sequentially determined using the current pulse technique in a cost effective manner. In embodiments of the invention, a single circuit can be multiplexed to many thermal probes.
[0000] D. Conclusion
[0054] The foregoing disclosure of examples and embodiments of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many variations and modifications of the embodiments described herein will be obvious to one of ordinary skill in the art in light of the above disclosure. The scope of the invention is to be defined only by the claims appended hereto, and by their equivalents.
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Systems and methods are described for identifying characteristics and defects in material such as semiconductors. Methods include scanning a thermal probe in the vicinity of a semiconductor sample, applying stimuli to the thermal probe, and monitoring the interaction of the thermal probe and the semiconductor. The stimulus can be applied by a variety of methods, including Joule heating of a resistor in the proximity of the probe tip, or optically heating a tip of the thermal probe using a laser. Applications of the invention include identification of voids in metallic layers in semiconductors; mapping dopant concentration in semiconductors; measuring thickness of a sample material; mapping thermal hot spots and other characteristics of a sample material.
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This application is a continuation of prior application Ser. No. 09/337,923, filed Jun. 22, 1999 now U.S. Pat. No. 6,224,125.
TECHNICAL FIELD
This invention relates to trailers and, more particularly, to trailer and top rail components used in the construction of trailers.
BACKGROUND
High strength is a desirable characteristic in trailers, but the desire for strength typically competes with the needs for space and aesthetically pleasing construction. An important area of the trailer is the top perimeter corner which is formed by a top rail. Though successfiily increasing strength, previous endeavors to strengthen top rails have sacrificed space and/or aesthetics.
Another aesthetic and fimctional concern, for trailers and the top rails in particular, is how awnings are mounted on the top rails. Presently, awnings are removably mounted on trailers by mounting strips. The mounting strips are fastened to the exterior surface of the trailers, usually the top rails, with conventional fasteners such as nuts and bolts. Thus, the mounting strips are raised significantly above the exterior surfaces of the traiers and the heads of the fasteners are typically exposed thereby detracting from the aesthetic value of the trailers. Further, the fasteners compromise the integrity of the top rails reducing strength and providing a pathway for water entry.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide an improved top rail assembly providing increased strength without unacceptably sacrificing space and aesthetics.
It is another object of the present invention to provide an improved top rail assembly providing an aesthetically and fimctionally improved awning mount.
In carrying out the foregoing and other objects, the present invention contemplates an improved vehicle top rail assembly having a vehicle shell member with a substantially rigid body. The body defines an outer surface that has a recessed awning groove. The groove includes an open mouth for receiving an awning member.
In a preferred embodiment, the awning mount groove is cylindrical, and the open mouth is positioned above the outer surface and defined between a pair of opposed legs extending outwardly from the outer surface. The open mouth is preferably narrower than the largest dimension of the awning mount groove.
The present invention further contemplates a top rail assembly for joining a side wall and a roof of a vehicle, preferably a trailer. The top rail side wall and roof connections are for connecting to a side wall and a roof, respectively. A transition section extends between and joins the side wall and roof connections, and a support brace extends between a side wall brace tab and a roof brace tab of the side wall and roof connections, respectively.
In a preferred emboddnent, the support brace includes a substantially flat roof foot which is removably attached to the roof brace tab by a fastener, so that the transition section and the support brace define a wire chase opening therebetween. The support brace also includes a side wall foot. The side wall foot defines a recess which receives the side wall brace tab therein.
The present invention also contemplates incorporating the top rail assembly into a vehicle, preferably a trailer having a roof, side walls, and a floor supported on a vehicle frame. The top rail assembly joins the side walls to the roof and provides an aesthetically pleasing awning mount groove, so that awnings can be mounted on the trailer when stationary.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of a trailer including a top rail according to the present invention; and
FIG. 2 is a transverse cross-sectional view of the top rail taken along line 2 — 2 in FIG. 1 .
DETAILED DESCRIPTION
Referring to the drawings in greater detail, the top rail assembly 20 shown in FIGS. 1 and 2 includes a support brace 22 and a rail body 24 defining an awning mount groove 26 . The top rail assembly 20 is incorporated into a vehicle 28 , preferably a trailer, to join a roof 30 with side walls 32 of the trailer 28 .
The trailer 28 includes a floor 34 ;. which along with the roof 30 and side walls 32 , are supported on a trailer frame 36 . The trailer also includes many conventional features such as a hitching mechanism 38 and a plurality of ground-engaging wheels 40 . The wheels 40 are rotatably mounted on and support the trailer frame 36 , and the hitching mechanism 38 is connected to the front of the trailer frame for coupling the trailer 28 with a towing vehicle (not shown). These conventional features and others of the trailer 28 are described to the extent necessary for an understanding of the invention.
The support brace 22 is a substantially rigid and elongated interior structural member used to support and strengthen the rail body 24 . The support brace has a substantially flat middle section 42 , a roof foot 44 , and a side wall foot 46 . The roof foot 44 is substantially flat and extends from the middle section 42 at an angle of approximately 45°. The roof foot 44 is substantially parallel to a roof member 48 connected to the rail body 24 . The side wall foot 46 extends from the middle section 42 at an angle of approximately 45° and defines a recess 50 opening toward a side wall member 52 connected to the rail body 24 . The recess 50 is defined between an upper tang 54 and a lower tang 56 which extend toward the side wall member. The side wall foot is substantially parallel to the side wall member 52 .
The rail body 24 is a unitary, substantially rigid, and elongated exterior shell member used to connect the roof members 48 to the side wall members 52 . To that end, the body includes a roof connection 58 and a side wall connection 60 . The roof connection 58 includes a roof end wall 62 and a roof brace tab 64 . The roof members 48 nest in the roof connection 58 against the end wall 62 and on top of the roofbrace tab 64 . The roofbrace tab 64 is preferably attached to the roof foot 44 ofthe support brace 22 by a weld. Alternatively as shown, fasteners 66 are used to removably connect the roof foot 44 to the roof brace tab 64 . If desired, a portion of the fastener 66 , such as the nut or head of the bolt, is welded to the top of the roof brace tab 64 to fix its location and permit easy removal and replacement of the support brace 22 .
The side wall connection 60 includes an upper end wall 68 , an outer retaining wall 70 , and a side wall brace tab 72 , which is shorter than the roof brace tab 64 . The side walls member 52 are held between the outer retaining wall 70 and the side wall brace tab 72 , and the ends of the side walls abut against the upper end wall 68 of the side wall connection 60 . The side wall brace tab 72 is received in the recess 50 of the side wall foot 46 , so that the upper tang 54 rests on top of the upper end wall 68 to secure the support brace 22 in place as it extends between the side wall tab and the roof tab. Though the support brace 22 can be attached to both tabs 64 , 72 or a selected one of the tabs, it is preferably connected to the side wall brace tab 64 .
The side wall connection 60 and the roof connection 58 are preferably joined by a transition section 74 extending therebetween. The transition section 74 is preferably arcuate and defines the awning groove 26 therein. A wire chase opening 76 is defined between the transition section 74 and the middle section 42 of the brace 22 . Wires and other components (not shown) are passed through the opening 76 thereby conserving space and achieving an aesthetically pleasing trailer interior. Because the brace 22 is removable, additional components can, from time to time, be easily run through the wire chase opening 76 , and the components in the opening 76 are easily accessible for maintenance. Transition section 74 includes a generally upwardly extending side marginal portion 74 a adjacent sidewall 32 , a generally horizontally extending top marginal portion 74 b adjacent roof 30 , and an out-wardly arched intermediate portion 74 c between side marginal portion 74 a and top marginal portion 74 b.
The awning mount groove 26 is defined in the top marginal portion 74 b of transition section 74 of the body 24 and is substantially continuous extending through the length of the body. The groove 26 is preferably recessed into the body 24 and is substantially cylindrical having an upper open mouth 78 . The mouth 78 is positioned above the outer surface 24 a of the body and is defined between a pair of opposed legs 80 , 82 extending outwardly from the body 24 , while groove 26 is desposed below outer surface 24 a . The inner leg 82 is longer than the outer leg 80 , so that the mouth 78 opens toward the side wall 32 of the trailer 28 . Both of the legs are arcuate to make the groove cylindrical. The ends of the legs 80 , 82 are spaced apart, so that the mouth is narrower than the largest dimension of the groove, that is, a diameter line. The base of the groove is defined by an inwardly extending bottom segment 84 . The segment 84 is arcuate and extends into the wire chase opening 76 . The legs 80 , 82 and the bottom segment 84 are integrally formed with the body 24 eliminating the need for additional fasteners.
Because it is integral and recessed, the awning mount groove 26 is aerodynamic, aesthetically pleasing, and inconspicuous. Further, the integral feature of the groove does not provide a path for water entry into the trailer. The awning mount groove 26 allows an operator to removably attach an awning 86 , over a door 88 for example, by inserting an awning member in the groove 26 when the trailer 28 is stationary.
Thus, a top rail assembly 20 is disclosed which utilizes a support brace 22 and an integrally provided awning mount groove 26 to provide a strengthened trailer structure with enhanced aesthetics and space utilization. Further, the top rail is not susceptible to water penetration
Although preferred forms of the invention have been described above, it is to be recognized that such disclosure is by way of illustration only, and should not be utilized in a limiting sense in interpreting the scope of the present invention. Modifications to the exemplary embodiments, as herein above set forth, could be readily made by those skilled in the art without departing from the spirit of the appended claims.
The inventor hereby states the intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of his invention as pertains to any apparatus or method not materially departing from but outside the literal scope of the invention as set out in the following claims.
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A top rail assembly ( 20 ) utilizes a support brace ( 22 ) and an awning mount groove ( 26 ) recessed in a rail body ( 24 ) to provide a strong top rail assembly ( 20 ) without using undue space or degrading aesthetics. The brace ( 22 ) extends between a side wall brace tab ( 72 ) and a roof brace tab ( 64 ) to reinforce the top rail body ( 24 ) and define a wire chase opening ( 76 ) between the brace ( 22 ) and a tansition section ( 74 ) of the body ( 24 ). The groove ( 26 ) is recessed into the rail body ( 24 ) and is defined by two opposed legs ( 80, 82 ) and a bottom segment ( 84 ) which are integral to the rail body ( 24 ).
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CROSS REFERENCE TO RELATED APPLICATION
This application is a division of application Ser. No. 440,840, filed Nov. 12, 1982 now U.S. Pat. No. 4,490,543 issued Dec. 25, 1984.
BACKGROUND OF THE INVENTION
In addition to being used in cancer chemotherapy, cisplatin is also known as a radiation sensitizer. That is, such that the cisplatin enhances the effect of ionizing radiation on malignant tumors in order to improve local and regional cancer treatment by radiation, see, for example, Overgaard, et al., Cancer Treatment Reports Vol. 65, Nos. 5-6, May/June, 1981, p. 501-503, which is incorporated herein by reference. There, it is reported that cisplatin will enhance the radiation response in tumors by a factor of between 1.2 and 1.7 time the effectiveness if no cisplatin is used. The report goes on to describe the use of cisplatin as a marked and selective enhancement of radiation's effects in solid tumors. Cisplatin has the formula: ##STR1## The chemical name for cisplatin is cis-diaminedichloroplatinum(II). It is a square planar molecule and its effectiveness in biological systems is believed to be related to its configuration. The compound was recognized for its biological significance in the 1960's and its radiation sensitizing properties were demonstrated in the mid-1970's.
While cisplatin per se has been known as an effective radiation sensitizer, it does have problems which have inhibited its practical use. The primary problem is its high level of toxicity to normal living cells. Thus, while it may successfully sensitize a carcinoma, making it highly susceptible to radiation treatment, it also is quite toxic to the surrounding normal cells. There is, therefore, a real and continuing need to develop a radiation sensitizer which is at least equally as effective as cisplatin with respect to the enhancement of sensitivity of carcinomas to radiation, but which will allow such sensitization without being toxic to surrounding normal living cells.
Needless to say, if one could develop a radiation sensitizer of high level sensitizing effect, but with minimal toxicity to surrounding normal living cells, the net effect would be that smaller doses of radiation could be used to give the effect now achieved with only larger radiation doses and thus, the total body exposure to radiation reduced. Alternatively, for a given radiation dose, its effectiveness could be increased without fear of causing high level toxicity to surrounding normal tissue cells.
It is a primary objective of the present invention to provide a radiation sensitizer which is at least equal to cisplatin in selective enhancement of radiation response, but which provides such radiation response with a much, much lower toxicity level to normal live cells.
An additional objective of the present invention is to provide a radiation sensitizer which is at least equal to cisplatin in enhancement of radiation response, but which is several times less toxic than cisplatin to normal living cells.
A further objective of this invention is to provide a radiation sensitizer which is at least equal to cisplatin in radiation sensitization effect, but which is estimated to be up to ten times less toxic to normal cells.
Another object is to provide a compound which like cisplatin itself has antineoplastic properties.
A still further objective of the present invention is to provide a molecular tracer which is fluorescent, thus providing a unique and highly effective biological tracer which is capable of binding to DNA nucleotides, proteins, and lipids.
Yet another objective of this invention is to provide a fluorescent biological tracer which also will function as an effective biological stain for use in electron microscopy and fluorescence microscopy.
Still another objective of the present invention is to provide a radiation sensitizer that has stability and solubility properties which make the compounds easy to administer in dosage quantity.
And another objective of the present invention is to provide a radiation sensitizer which is soluble in water and soluble in common universal solvents such as dimethylsulfoxide, methyl alcohol, ethyl alcohol, acetone, etc.
Another very important objective of the present invention is to provide a highly effective, single step synthesis for production of fluorescently labeled cisplatin type compounds, which do not employ cisplatin at all in the synthesis procedure, but instead employ readily available compounds in a single step, direct combination synthesis.
The method and manner of accomplishing each of the above objectives, as well as others, will become apparent from the detailed description of the invention which follows hereinafter.
SUMMARY OF THE INVENTION
This invention relates to cisplatin type fluorescently labeled compounds which are effective radiation sensitizers. In particular, the compounds are bis(5-aminofluorescein)dichloroplatinum(II) (abbreviated cis-CFP) or certain substituted analogs thereof. They are equal to cisplatin from the standpoint of their radiation sensitivity enhancement, but are up to ten times less toxic to normal living cells than cisplatin. In addition, the compounds are highly effective, fluorescent biological tracers. The invention also relates to a unique, single step synthesis for preparing fluorescently labeled cisplatin type compounds, without ever employing cisplatin in the synthesis route. As a result, the synthesis involves a platinum salt and a relatively non-toxic 5-aminofluorescein, which are readily available.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings are graphs illustrating the good radiation sensitizing properties of the compounds of this invention, coupled with their low toxicity level compared to cisplatin.
DETAILED DESCRIPTION OF THE INVENTION
The compounds of this invention have the following formula: ##STR2## wherein "X" is a halide and R and R' are selected from the group consisting of hydrogen, C 1 to C 12 alkyl, C 1 to C 12 alkenyl, C 1 to C 12 alkynyl, and aryl. Preferably "X" is a chloride or bromide, and most preferably chloride. It is preferred that R and R' be selected from the group consisting of C 1 to C 6 alkyl, alkenyl, alkynyl, and aryl. Most preferably, both R and R' are hydrogen.
The very most preferred compound of the invention is bis(5-aminofluorescein)dichloroplatinum(II).
The compounds of the present invention can be thought of as fluorescein derivatives of cisplatin.
Cisplatin has been known for several decades but has only become biologically important since about the mid-1960's. It is a square planar molecule known to have adverse properties to normal, but especially to neoplastic cells. It is also known as an effective radiation sensitizer. The term "radiation sensitizer" refers to enhancement of the effect of ionizing radiation on cells, most typically malignant cells in order to improve local and regional cancer treatments. Cisplatin selectively sensitizers and enhances the effective radiation response in malignant growths with a lesser effect in normal tissues. Thus, cisplatin has been accorded some high level interest, because of its potential use in chemotherapy. However, one primary disadvantage with cisplatin is that it has a high level of toxicity to normal tissue cells.
Surprisingly, and contrary to the expectations in working with cisplatin per se, the fluorescein derivatives of this invention are equal to cisplatin as radiation sensitizers, but, contrary to cisplatin, have a very low level toxicity to surrounding tissue cells. In fact, data developed to date, reveal a toxicity level up to as much as ten times lower than cisplatin. As a result, the compounds of this invention, and particularly the most preferred compound bis(5-aminofluorescein)dichloroplatinum(II), can be used as a much more effective radiation sensitizer than cisplatin. In particular, since the aminofluorescein derivative has a low toxicity level, larger quantities can be used in dosage treatments. As a result, successful radiation treatments can occur with much smaller radiation doses, resulting in overall reduced body exposure to radiation. Then too, large doses of the radiation sensitizer can be used, increasing the radiation sensitization effect, without any significant worry of the high level toxicity to normal cells. In particular, toxicity levels of the most preferred compound of this invention are up to ten times less than cisplatin.
The compounds of the present invention are also useful as biological tracers, since they are both fluorescent and have high binding capabilities to nucleic acids, proteins and lipids. Prior to the development of the compounds of this invention, it is not believed that there has been a biological tracer which is both fluorescent and also offers binding properties similar to that of cisplatin in that it may bind to nucleic acids, proteins and lipids, and thus be easily traceable. This fluorescent property, coupled with the binding ability to biologically important compounds, allows for fluorescent labeling of cells in biological work.
While the compounds discussed have been referred to as platinum compounds, it is possible that other compounds can be made employing as the metal atom, any of the metals of the platinum metal series, that is, rubidium, rhodium, palladium, osmium, irridium, and platinum. It is therefore contemplated as still within the scope of this invention if the central metal atom of the platinum compounds is replaced with other of the referred to metals of the platinum metal series.
Another highly important feature and advantage of the compounds of the present invention is that they have stability and solubility characteristics which make them easy to work with from the standpoint of dosage units. That is to say, they are soluble in water, they are relatively stable, and they will dissolve in many universally employed solvents such as dimethylsulfoxide, methanol, ethanol and acetone.
A surprisingly simple and straightforward single step reaction synthesis has been developed for producing the compounds of this invention. The method is surprising because one would normally except cisplatin per se to be the starting material, since the compounds are derivatives of cisplatin. However, cisplatin is not involved in the reaction at all. And yet, the compound which is produced has all of the radiation sensitivity properties of cisplatin. In accordance with the process of this invention, 5-aminofluorescein (Isomer I), or a substituted 5-aminofluorescein, is reacted with an alkali metal tetrachloroplatinate(II) in a single step, direct combination synthesis. 5-aminofluorescein (Isomer I) has the formula: ##STR3## The alkali metal tetrachloroplatinate(II) is preferably potassium tetrachloroplatinate(II) of the formula K 2 [PtCl 4 ]. In the preferred methodology, an aqueous solution of potassium tetrachloroplatinate(II) is mixed with a hot methanol solution of 5-aminofluorescein, with the molar ratio of potassium tetrachloroplatinate(II) to 5-aminofluorescein being 1:2. The solutions are mixed and the mixture is heated (with evaporation) at a slightly elevated temperature, perhaps 60° C. After cooling to room temperature, a brown precipitate forms which can be separated and recrystallized.
The following examples are offered to further illustrate, but not limit, the invention. It is understood that modifications may be made in the illustrated examples.
EXAMPLES
Preparation of bis(5-aminofluorescein)dichloroplatinum(II) was accomplished using direct combination of an aqueous solution of potassium tetrachloroplatinate(II) and 5-aminofluorescein. In particular 0.415 grams of K 2 [PtCl 4 ] in 25 milliliters of water was added to 0.694 grams of 5-aminofluorescein in 50 milliliters of boiling methanol. They were mixed, and the solution was kept at about 60° C. for one hour. Thereafter, it was allowed to cool, at which point a brown precipitate was observed. The precipitating compound was filtered, washing a little with absolute ethanol, and then with diethyl ether. The brown compound remained. It weighed 0.4 grams.
The reaction process was run again, exactly as described above, and gave a brown solid of 0.5 grams.
Nuclear magnetics resonance (NMR) testing, infrared (IR) analysis, visible-UV spectroscopy, and quantitative, elemental analysis all confirmed the presence of bis(5-aminofluorescein)dichloroplatinum(II). In these runs, the starting platinum compound came from the Alpha Division of Ventron Corporation, and the starting 5-aminofluorescein compound came from Sigma Chemical in St. Louis, Mo. Of course, other convenient and suitable sources for the starting materials may be utilized.
Numerous repetitions of the synthesis procedure shown here, have occurred and all upon various analysis techniques mentioned herein confirm the presence of bis 5-aminofluorescein)dichloroplatinum(II).
The process was repeated using as the starting material K 2 [PtBr 4 ] and the resulting product was bis(5-aminofluorescein)dibromoplatinum(II).
The bis(5-aminofluorescein)dichloroplatinum(II) prepared in the manner previously described herein, was tested for effectiveness as a radiation sensitizer. In particular, the compound was complexed with nucleotides in vitro. The stability of the compound was studied in a buffered saline solution over a period of time. Finally, the cell growth effects of the compound from the standpoint of its effects on living cells were studied, as described below.
The drawings illustrate the effective nature of the compounds of this invention as radiation sensitizers, and compare the toxicity level of the compounds of this invention with the toxicity level of cisplatin from the standpoint of their effects on living cells.
FIG. 1 shows the effectiveness of the compound of this invention, in particular bis(5-aminofluorescein)dichloroplatinum(II) in terms of its effectiveness as a radiation sensitizer. In particular, in looking at FIG. 1, the "x" axis shows radiation dose as measured in kilorads (krad). The "y" axis shows the surviving fraction of bacterial cells (S. typhimurium Tm 677). The line represented by black dots and dashes shows the effect of radiation alone on this bacterial system under a nitrogen blanket. This simulates anaerobic conditions in vivo. The lines showing squares with dashes and pulses with dashes shows the decrease in survival produced by 20 um and 100 um cis-CFP respectively over a range of radiation dosages. The radiosensitization produced by cis-CFP exhibits a dose dependent effect. It also exhibits a much reduced toxicity as compared to equamolar concentrations of cisplatin; this makes it difficult to make direct comparisons. Studies using the S. typhimurium Tm 677 bacterial system produce the following data.
TABLE 1______________________________________ Toxicity after 1/2 hour at room temperature RadiationConcentration of [no radiation EnhancementCompound survival] Ratio______________________________________Cisplatin 100 uM 10% 2.4cis-CFP 100 uM 100% survival 1.6______________________________________
Even though the enhancement of the 100 uM concentration is less for cis-CFP than for displatin, the extreme differences in toxicity demonstrate the utility of cis-CFP as compared to cisplatin.
Though difficult to compare directly, other work using mice to study cisplatin-induced radiosensitization shows a radiation enhancement ratio of up to 1.7. This is comparable to the 1.6 value demonstrated for cis-CFP in the bacterial system.
Also, cisplatin under nitrogen is an assay using E. coli exposed to 5×10 -5 M cisplatin shows an enhancement ratio of about 1.77. It therefore can be seen that although direct comparision is difficult, they are comparable in radiation sensitizing ability.
FIG. 2 shows the growth of a culture of Tetrahymena in a nutrient medium which comprises 2% by weight of proteose peptone, 0.1% by weight sodium hydrogen phosphate, 0.1% sodium acetate and with the balance being distilled water. The "x" axis shows culture growth in time with the "y" axis indicating media density, an indication of cell numbers. As can be seen, the greatest cell growth is exhibited in the control, which are free living and growing protozoan cells in the presence of a nutrient. The toxicity of cisplatin when added to the control solution at a concentration of 10 -5 molar is also shown. The toxicity of the compounds of this invention at 10 -4 molar and 10 -5 molar concentrations are likewise shown. It can be seen that the level of toxicity compounds of the present invention is much, much less at a given molar concentration than is cisplatin. This is further illustrated in FIG. 3, which shows the same free living protozoan cell Tetrahymena, but shows the motility rate declining in the presence of cisplatin and a compound of the invention. Cisplatin is the dotted line and the compound of the invention is the solid line. There, the "x" axis measures time of exposure with the "y" axis measuring the motility rate of the organisms. The steeper the line indicating the mobility of the organism, the more toxic the compound. There, the concentration in both instances of cisplatin and the compound of the invention was 2×10 -3 molar. It can be seen that at any given time, the mobility is much more reduced by cisplatin than the compound of this invention, indicating a much higher toxicity level of cisplatin.
It therefore can be seen that the compounds of the present invention are substantially equal in radiation sensitizing effect to cisplatin, but that they are up to as many as ten times less toxic to normal living cells, see FIGS. 2 and 3 and the data presented therein.
Thus, the invention accomplishes at least all of its stated objectives.
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This invention relates to cisplatin type fluorescently labeled compounds. In particular, the compounds are bis (5-aminofluorescein)-dichloroplatinum (II) or certain substituted analogues thereof. The compounds are useful as radiation sensitivity enhancers and as fluorescent biological tracers. The invention also relates to a unique, single step synthesis for preparing said compounds.
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CROSS REFERENCE TO RELATED APPLICATIONS AND CLAIM TO PRIORITY
This application is a divisional of application Ser. No. 09/995,525, filed Nov. 28, 2001, now U.S. Pat. No. 6,743,318 the disclosure of which is incorporated herein by reference and priority to which is claimed pursuant to 35 U.S.C. § 120.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention generally relates to wood products and, more particularly, relates to methods of manufacturing consolidated cellulosic panels.
2. Description of Related Technology
Consolidated cellulosic panels, such as fiber board, paper board, particle board, and the like, are typically comprised of wood furnish such as saw dust, shavings, chips, or specially ground fibers, compressed with a binding agent or resin under heat and pressure. Such boards can be used in a variety of applications including, but not limited to, exterior house siding, interior and exterior door facing panels or door skins, cabinet doors, paneling, moulding, etc.
It is often desirable to manufacture such panels to a uniform basis weight and caliper. If the panels are flat this can be accomplished by compressing a mat between first and second flat faced dies. However, if one of the faces needs to be deeply contoured, such die compressions have proven to be problematic. For example, if a first die has a contour corresponding to the desired shape of the panel, and the second die has a flat face, the mat compressed therebetween will have a non-uniform caliper, with the thinner areas of the mat being compressed to a higher density than thicker areas. This is especially true with fiberous materials that do not flow under pressure.
Current methods of producing such panels therefore typically require that a mat having first and second opposed flat surfaces be compressed according to conventional methods, and that one or more of the surfaces then be machined to have the desired contour. For example, a router may be used to shape the surfaces. U.S. Pat. No. 4,175,106, assigned to the present assignee, discloses such a process. Such tools, however, cannot easily produce sharp inside corners, are relatively slow, and require complex, expensive equipment.
Another method requires contoured, complementary, dies on both the top and bottom to produce a substantially uniform thickness through the contoured and non-contoured areas. If one of the top or bottom needs to be flat, or alternatively shaped, the panel must undergo an added machining step adding time, expense and waste to the operation. Shallow contouring of one face is typically done in an embossing operation, or with an embossing die, but the depth of embossing is greatly limited.
SUMMARY OF THE INVENTION
In accordance with one aspect of the invention, a method for producing a consolidated cellulosic article is provided. The method comprises the steps of providing a mat of cellulosic material and binder resin, providing a first contoured front platen having a first pattern, providing a first contoured rear platen having a pattern generally corresponding to the pattern of the front platen, consolidating the mat between the front platen and the rear platen under heat and pressure to form a molded softboard having a contoured front surface and a correspondingly contoured rear surface, the softboard having a substantially uniform density and a substantially uniform caliper, removing portions of the molded softboard to form a softboard having a front surface and a rear surface with desired contours, providing a second contoured front platen having a contour substantially corresponding to the contour of the front surface, providing a second contoured platen having a contour substantially corresponding to the contour of the rear surface, and consolidating the softboard between the second contoured front platen and the second contoured rear platen under heat and pressure.
In accordance with another aspect of the invention, a method of producing a consolidated cellulosic article is provided comprising the steps of compressing a mat of cellulosic material and a binder resin between first and second contoured platens to produce a softboard having first and second opposed contoured sides, removing cellulosic material from the softboard along one of the first or second sides in a planar fashion, and subsequently compressing the mat between third and fourth platens, the third platen being contoured in a manner similar to the first side of the softboard, the fourth platen being contoured in a manner similar to the second side of the softboard.
In accordance with another aspect of the invention, a system for producing a consolidated cellulosic article is provided comprising a primary press, a removal tool, and a secondary press. The primary press includes first and second platens and a drive with the first and second platens having opposed, complementarily contoured, die surfaces. The drive is adapted to compress the first and second platens toward one another. The removal tool includes a blade for removal of cellulosic material in a planar fashion. The secondary press has first and second platens and a drive. The first and second platens have opposed die surfaces. The drive is adapted to compress the first and second platens toward one another.
These and other aspects and features of the invention will become more apparent upon reading the following detailed description when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view of an article constructed in accordance with the teachings of the invention;
FIG. 2 is a partial sectional view of an article being compressed by a primary press according to the teachings of the invention;
FIG. 3 is a partial sectional view of an article being machined after the primary press according to the teachings of the invention;
FIG. 4 is a partial sectional view of an article being compressed by a secondary press according to the teachings of the invention;
FIG. 5 is a partial sectional view of an article being machined with an alterative removal plane according to the teachings of the invention;
FIG. 6 is a partial sectional view of an article being machined using an alternative tool according to the teachings of the invention; and
FIG. 7 is a schematic representation of a system constructed in accordance with the teachings of the invention.
While the invention is susceptible to various modifications and alternative constructions, certain illustrative embodiments thereof have been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the invention to the specific forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention as defined by the appended claims.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, and with specific reference to FIG. 1 , an article constructed in accordance with the teachings of the invention is generally referred to by reference numeral 20 . While the article 20 is depicted as a six panel door facing, it is to be understood that the teachings of the invention can be employed in the construction of any number of other consolidated cellulosic articles having a contoured surface. Such articles include, but are not limited to, exterior house siding, flooring, furniture components, paneling, and cabinet doors.
As shown in FIG. 1 , the article 20 includes a first or top surface 22 , a second or bottom surface 24 , first and second side edges 26 , 28 , and first and second end edges 30 , 32 . The top surface 22 is contoured, whereas the bottom surface 24 is flat or planar in the depicted embodiment. More specifically, the top surface 22 includes a plurality of indentations 34 of various dimension and depth to provide an appearance desirable for the end application of the article 20 . In the depicted embodiment, the bottom surface 24 is flat to facilitate attachment of the article 20 to a door core, but it is to be understood that the article 20 may include a back surface having a non-flat contour as well.
Referring now to FIG. 2 , a primary press 36 according to the teachings of the invention is depicted compressing a mat 38 . The mat 38 is contemplated to be comprised of cellulosic material, such as wood fiber, mixed with a binding agent or resin. The binding agent may be a thermoset resin such as a phenolic resin or isocyanate. The mat 38 may be formed by sprinkling such fiber and binding agent or a moving conveyor belt. Variations in the height of the mat 38 may be removed with a scalping roller or the like. The belt is often of a mesh or otherwise perforated material to enable a vacuum device to hold the fiber on the belt. The primary press includes an upper platen or die 40 , a lower platen or die 41 , and a drive mechanism 42 . The upper and lower platens are similarly contoured with complementary protrusions 43 and indentations 43 a . The drive mechanism 42 is depicted as a hydraulic cylinder, but may be alternatively provided as with pneumatic actuators, chain and sprocket drives, pulley and belt drives, direct drive couplings to motors or other primary movers, etc. Each die 40 , 41 is preferably heated, as by a heat source 44 . The heat source 44 may be provided in the form of heat exchanger coils or channels through the dies 40 , 41 , through which heated fluid, e.g. water, is circulated, or in the form of separate hot platens.
The primary press 36 compresses the mat 38 to a first level of density and caliper to result in a softboard 45 as shown in FIG. 3 . A softboard is defined herein as a compressed mat of cellulosic fiber and a binding agent having a relatively low density, e.g., 10 to 30 lbs. per cubic foot. Such a softboard has sufficient strength to maintain its shape as opposed to being a loose pile of fiber, but would not be suitable for a solid product such as siding or doors. However, since the mat 38 is compressed between upper and lower dies 40 , 41 , having complementary configurations, the softboard 45 is compressed to a substantially uniform caliper and substantially uniform density. More specifically as noted in FIG. 3 , zone ∝ is of the substantially same height as zone β. Since the mat 38 begins with a uniform density and basis weight, after compression with such complementarily shaped dies 40 , 41 , the softboard 45 continues to have a uniform, although greater, density, and a uniform basis weight.
Once the softboard 45 is formed, it is machined in a planar fashion to reduce one or both of the top surface 22 or bottom surface 24 . In the embodiment depicted in FIG. 3 , the bottom surface 24 is machined by a rotary scalper 46 . The rotary scalper 46 includes an axle 47 from which a plurality of blades 48 radially extend. The axle 47 is connected to a suitable drive mechanism (not shown) such as a chain and sprocket drive, a pulley and belt arrangement, or a direct coupling to a primary mover, so as to rotate the axle 47 and blades 48 relative to the softboard 45 . In so doing, the contour of the bottom surface 24 is removed in the depicted embodiment of FIG. 3 , resulting in a flat or planar surface 50 .
In alternative embodiments, the bottom surface need not be completely flattened. The removal tool, be it the rotary scalper 46 , a circular (dado) saw blade ( FIG. 5 ), a band saw blade ( FIG. 6 ), a sander (not shown), or the like, may be controlled to remove all cellulosic material in the softboard 45 up to a predetermined removal plane 49 . For example, FIG. 5 depicts an alternatively machined softboard 45 wherein the removal plane traverses across the indentations 34 , thereby allowing a portion of the indentation 34 to remain in the bottom surface 24 . One of ordinary skill in the art will readily appreciate that the removal plane 49 can be located at any position within the softboard 45 and affect the ultimate shape of the top surface 22 or bottom surface 24 , accordingly.
Referring now to FIG. 4 , a secondary press 52 according to the teachings of the invention is depicted. The secondary press 52 preferably includes an upper platen or die 54 having a contour matching the contour of the top surface 22 , and a lower platen or die 56 having a surface 58 matching the contour of the bottom surface 24 . In the depicted embodiment, the bottom surface 24 is flattened, and thus the surface 58 is flat, but it is to be understood that if the bottom surface 24 otherwise shaped, e. g., machined to have a shape such as that of FIG. 4 , the lower die 56 would be similarly shaped.
The upper and/or lower dies 54 , 56 are coupled to a drive mechanism, such as a hydraulic cylinder 60 , to compress the softboard 45 therebetween. The upper die 54 includes protrusions 62 positioned and dimensioned to align with indentations 34 provided within the softboard 45 and further compress the softboard 45 to a lower caliper and higher density. Since portions of the softboard 45 have been removed below the removal plane 49 , the resulting article 20 has a variable basis weight across its length. Steam may be injected into the softboard 45 from an injector 63 during the secondary compression.
As indicated above, FIG. 6 depicts an alternative embodiment according to the teachings of the invention. In FIG. 6 , rather than employing a rotary scalper 45 to remove cellulosic material from the softboard 45 , a band saw 68 is employed. It is to be understood, that any number of other removal tools may be employed, including but not limited to, circular or dado saw blades and sanders.
Not only can the teachings of the invention be used to construct the article 20 having a contoured upper surface 22 and bottom surface 24 , with the article 20 having a uniform density and variable basis weight, but since the article 20 is compressed in dual stages, the cellulosic material removed can be gathered and reused in the creation of subsequent articles 20 . Accordingly, FIG. 7 depicts a system 70 , which may be constructed in accordance with the teachings of the invention, including the primary press 36 , the removal tool 45 , and the secondary press 52 , as well as recovery mechanism 72 , recycling mechanism 74 , a hopper 76 , and a mat former 78 . The gathering mechanism 72 may be provided in a number of forms, including, but not limited to, a basin or conveyor provided directly below the removal tool 45 . A vacuum may also be employed. Employing a conveyor, gravity may be used to allow the removal of cellulosic material to fall into the conveyor and be transported back to a reservoir or hopper of cellulosic material (not shown). Alternatively, the vacuum may be provided proximate the removal tool 45 for gathering the cellulosic material immediately upon removal from the article 20 .
From the foregoing, one of ordinary skill in the art will appreciate that the teachings of the invention can be employed to construct a consolidated cellulosic article having first and second surfaces contoured as desired, with a substantially uniform density and variable basis weight and caliper. Moreover, the article can be constructed in a manner enabling cellulosic material removed from the article in the process to be recycled and used in the creation of subsequent articles.
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A method and system for manufacturing a consolidated cellulosic article having first and second surfaces of a desired contour, a uniform density and variable caliper and basis weight are disclosed. The method and system employ a primary press having first and second similarly contoured platens to consolidate a mat of cellulosic material and a binding agent to a softboard having first level of density with first and second opposed sides of similar contour. A removal tool is then employed to remove cellulosic material from one or both of the first and second sides in a planar fashion. The resulting mat is then compressed a second time by a secondary press having first and second platens corresponding in shape to a higher density level while maintaining a substantially uniform caliper and basis weight.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a front transaxle device of a multi-wheel-drive vehicle.
2. Background Art
Conventionally, a multi-wheel-drive vehicle wherein four or more wheels are driven is known.
In this multi-wheel-drive vehicle, transaxle devices for supporting axles are disposed corresponding to the positions of the axles. For example, a rear transaxle device for supporting rear axles is disposed at a rear portion of the vehicle, and a front transaxle device for supporting front axles is disposed at a front portion of the vehicle. In a structure where six or more wheels are driven, a middle transaxle device for supporting middle axles is disposed at a longitudinally intermediate portion of the vehicle.
Furthermore, a transmission which transmits the power from a prime mover (e.g., an engine) is provided. By transmitting the power from the transmission to each of the transaxle devices, the wheels are driven through each of the axles.
In comparison with a two-wheel-drive structure, the above-mentioned multi-wheel-drive structure is more useful in that its driving performance over a bad road is good, and plenty of power is available for climbing a hill. Thus, this structure has come to be widely adopted by various kinds of vehicles such as automobiles, agricultural trucks, and the like.
Now, further improvement of such a multi-wheel-drive vehicle in terms of its driving performance over bad roads, cost-saving, maintainability, etc., is increasingly desired given the increasing popularity of such vehicles.
BRIEF SUMMARY OF THE INVENTION
An object of the invention is to provide a front transaxle device which gives improved braking performance to a multi-wheel-drive vehicle so as to improve further the driving performance of the vehicle over bad roads. Another object of the invention is to provide the front transaxle device with a simple structure so as to reduce manufacturing costs and enhance the maintainability thereof.
According to the present invention, a front transaxle device provided to a multi-wheel-drive vehicle comprises an input shaft for receiving power, a pair of left and right front axles supported in the front transaxle device, a differential connecting the left and right front axles in a differential manner, a pinion shaft, a clutch device which engages the pinion shaft with and disengages the pinion shaft from the input shaft, a rotary object interposed between the differential and the pinion shaft, and a brake device which brakes the rotary object. Therefore, the braking performance is improved and the vehicle's braking distance can be shortened. Thus, a multi-wheel-drive vehicle, which can run smoothly on a bad road and enhance fuel economy, may be available. Furthermore, by operating the clutch device, it is easy to select between the mode wherein the power is transmitted to the front wheels supported by the front transaxle device and the mode wherein the power is not transmitted to the front wheels. Thus, by linking the clutch device with operating means, a vehicle which can be put between 4-wheel-drive mode and 6-wheel-drive mode (for example) is available. Additionally, because the clutch device is disposed between the input shaft and the pinion shaft and the brake device is disposed at the rotary object, the two devices are separated and can avoid interfering with each other, thereby reducing the complexity of the layout.
The brake device comprises a piston which can be moved hydraulically, friction objects which engage with each other by the force of the piston, and a mechanism which maintains a constant stroke of the piston to engage the friction objects regardless of any abrasive reduction of the friction objects. Therefore, in spite of abrasive reduction of friction objects in the brake device, it is unnecessary to adjust the stroke of the piston to keep a good braking response of the brake device, thereby reducing the need for maintenance.
The rotary object is a middle shaft disposed between the pinion shaft and the differential and supported parallel to a rotational axis of the differential, and the middle shaft is engaged with the differential through a spur gear. Therefore, the parts of the brake device are arranged along and detached from the middle shaft parallel to the rotational axis of the differential. Thus, installation and removal of the brake device is easy, thereby resulting in good maintainability. Furthermore, because the middle shaft is connected with the differential through the spur gear, realignment using a shim and the like, which is necessary in a structure having the middle shaft connected with the differential through bevel gears, is not necessary. Such alignment can be eliminated.
A front transaxle device is provided to a multi-wheel-drive vehicle which has six or more wheels, wherein a pair of foremost wheels of the vehicle are supported and can be driven. A transmission provided to the vehicle is connected with the front transaxle device through a clutch device which is engaged when a brake operating means provided to the vehicle is operated to brake. Therefore, when the brake operating means is operated to its braking position by the linkage between the brake operating means and the clutch device, braking force is also transmitted to the pair of foremost wheels. Thus, the vehicle's braking distance at high speed can be shortened. Additionally, the front transaxle device can be bypassed when the brake device is not being operated, thereby enhancing fuel economy.
Other and further objects, features, and advantages of the invention will appear more fully from the following description.
BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES
FIG. 1 is a schematic diagram of a driving transmission system of a multi-wheel-drive vehicle including a front transaxle device of the present invention;
FIG. 2 is a horizontally sectional view of the front transaxle device;
FIG. 3 is an expanded horizontally sectional view of the front transaxle device, showing an automatic gap alignment mechanism, wherein a piston is located at its original brake-released position;
FIG. 4 is a sectional view of the same showing the state that the piston is moved at a stroke of length A from the state shown in FIG. 3, and friction discs are engaged with each other;
FIG. 5 is a sectional view of the same showing the state that the piston is moved at a stroke of length A from its original brake-released position when the friction discs are worn away;
FIG. 6 is a sectional view of the same showing the state that the piston is moved at a stroke of length B from the state shown in FIG. 5, and the friction discs are engaged with each other;
FIG. 7 is a sectional view of the same showing the state that the piston is returned at a stroke of length A from the state shown in FIG. 6 to its new brakeleased released position;
FIG. 8 is a horizontally sectional view of a modification of the front transaxle device wherein the brake device is disposed onto a pinion shaft;
FIG. 9 is a hydraulic circuit diagram of a control system for controlling front and rear brake devices;
FIG. 10 is a hydraulic circuit diagram of a control system for controlling the front and rear brake devices according to another embodiment; and
FIG. 11 is a diagram of the embodiment shown in FIG. 10, showing the state that a brake pedal is depressed and a clutch device linked with the brake pedal is engaged.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, a multi-wheel-drive vehicle 1 comprises a front transaxle device 10 disposed at its front portion, a middle transaxle device 16 disposed at its longitudinally intermediate portion, and a rear transaxle device 4 disposed at its rear portion. The front transaxle device 10 includes a pair of left and right front axles 11 , the middle transaxle device 16 includes a pair of left and right middle axles 25 , and the rear transaxle device 4 includes a pair of left and right rear axles 8 . Each of above-mentioned front, middle, and rear axles 11 , 25 and 8 supports each of front wheels 12 , middle wheels 26 , and rear wheels 9 , respectively, at their outer ends.
A front brake device 100 which serves as a first braking device is provided to the front transaxle device 10 , and rear brake devices 22 which serve as a second braking device are provided to the rear transaxle device 4 .
The front wheels 12 are steerable, i.e., rotatable leftward and rightward according to manipulation of a steering operating device (not shown).
A transmission 13 is provided in the rear transaxle device 4 . The power from an engine 3 installed in the body of the vehicle is transferred to the transmission 13 and changes rotational speed. Then, the power is used to drive the left and right rear wheels 9 through the rear axles 8 , and also, it is transferred to the middle transaxle device 16 so as to drive the middle wheels 26 through the middle axles 25 . Thus, the vehicle moves forward and backward by the driving of the rear wheels 9 and the middle wheels 26 , i.e., in 4-wheel-drive.
Alternatively, the power from the transmission 13 may be transferred to the front wheels 12 so as to drive all six wheels 9 , 12 and 26 , thereby enabling the vehicle to be put in 6-wheel-drive. This structure will be described later.
A structure of the rear transaxle device 4 will now be described.
The rear transaxle device 4 comprises a rear axle housing 31 which houses the transmission 13 together with the rear axles 8 . An input shaft 5 of the transmission 13 is connected to an output shaft 6 of the engine 3 through a belt-type automatically continuous variable transmission (hereafter “CVT”) 7 comprising split pulleys and a belt.
The transmission 13 comprises a torque sensor 34 and a speed-changing gear mechanism 35 . The torque sensor 34 detects torque, which is applied on the wheels as load, and translates the torque into an output signal. The speed-changing gear mechanism 35 is operated by manipulating a speed-changing operating device like a lever or a pedal (not shown) disposed outside the rear axle housing 31 .
The rear axle housing 31 also houses a differential 32 interposed between the speed-changing gear mechanism 35 and the pair of left and right rear axles 8 . The differential 32 connects the left and right rear axles 8 differentially with each other. The differential 32 is provided with a differential locking mechanism 33 in the rear axle housing 31 . The differential locking mechanism 33 is linked with a differential-locking device like a lever or a pedal (not shown) disposed outside the rear axle housing 31 so as to lock the differential 32 . A power take-off casing 15 is fixed on a side portion of the rear axle housing 31 . The power take-off casing 15 is provided therein with a power output section from which power is transferred to the middle transaxle device 16 and the front transaxle device 10 .
The above-mentioned input shaft 5 is supported laterally in the rear axle housing 31 and projects outwardly from either the left or right sides thereof. A follower split pulley 36 is provided on the outwardly projecting portion of the input shaft 5 , which serves as an input section receiving the power from the engine 3 . The output part of the CVT 7 is formed by this follower pulley 36 . The CVT 7 is normally formed such that the speed reduction ratio is automatically steplessly reduced according to the increase of rotary speed of the engine 3 .
In the rear axle housing 31 , a main shaft 37 is provided coaxially with the input shaft 5 . The main shaft 37 and the input shaft 5 are connected with each other through above-mentioned torque sensor 34 . The torque sensor 34 detects various type resistances such as rolling resistance, air resistance, acceleration resistance, and grade resistance generated from each of the driven wheels, and outputs detection signals into a controller (not shown). The controller adjusts the degree of opening of a throttle valve of the engine 3 corresponding to the detection signals, thereby serving as a torque sensing governor.
In the rear axle housing 31 , a counter shaft 41 is disposed parallel to the main shaft 37 . The speed-changing gear mechanism 35 is provided between both shafts 37 and 41 .
The speed-changing gear mechanism 35 comprises a plurality of (in this embodiment, two) drive gears fixed on the main shaft 37 to rotate together with the main shaft 37 , and a plurality of (in this embodiment, two) transmission gears supported rotatably on the counter shaft 41 to engage with the respective drive gears on the main shaft 37 , thereby providing various (in this embodiment, two, i.e., high and low) gear ratios. In order to reverse the rotational direction of the counter shaft 41 while the main shaft 37 is rotated in a fixed direction, the speed-changing gear mechanism 35 also comprises a driving reverse gear fixed on the main shaft 37 , a reverse gear supported rotatably on the counter shaft 41 , and an idle gear through which both the reverse gears on the shafts 37 and 41 engage with each other.
A gear-changing clutch slider 47 is axially slidably but not relatively rotatably fitted onto the counter shaft 41 through a spline. By sliding the gear-changing clutch slider 47 , one gear is selected from among the two transmission gears and the reverse gear on the counter shaft 41 to engage with the counter shaft 41 through the gear-changing clutch slider 47 . This selection brings the counter shaft 41 into a high-speed regularly directed rotation, a low-speed regularly directed rotation, or a reversely directed rotation depending upon which gear is chosen. Also, the gear-changing clutch slider 47 can be located at its neutral position where it engages with none of the gears. The gear-changing clutch slider 47 is linked with the above-mentioned speed-changing device (not shown).
The counter shaft 41 is fixedly provided thereon with an output gear 51 adjacent to one of its ends, thereby transmitting the rotation of the counter shaft 41 to the above-mentioned differential 32 .
The differential 32 generally uses bevel gears to connect the left and right rear axles 8 in a differential manner. An input gear 53 is disposed on a differential casing, which houses the bevel gears, so as to engage with the output gear 51 . The differential locking mechanism 33 is disposed around one of the axles 8 so as to engage the differential casing with and disengage the differential casing from the axle 8 according to operation of the differential locking lever (not shown). When the differential casing engages with the axle 8 , both the axles 8 are locked together, i.e., the differential 32 is locked.
The rear brake devices 22 are provided respectively on the pair of left and right rear axles 8 so as to apply brake force onto both rear axles 8 according to the operation of a later-discussed brake pedal.
One end of the counter shaft 41 extends toward one of the left or right sides into the power take-off case 15 , and a bevel gear 62 is fixed onto its end portion. An output shaft 63 is supported in the longitudinal direction of the vehicle and perpendicularly to the counter shaft 41 in the power take-off case 15 . A bevel gear 64 is fixed onto the output shaft 63 and engages with the bevel gear 62 .
The output shaft 63 projects forward from the power take-offcase 15 , and connects to a transmission shaft 87 of the middle transaxle device 16 through a drive shaft 17 .
Next, the middle transaxle device 16 will be described.
The transmission shaft 87 is supported in the longitudinal direction of the vehicle, and its rear end projects rearward so as to receive driving force from the rear transaxle device 4 . The transmission shaft 87 also projects forward from the middle transaxle device 16 , thereby forming an output section for the front transaxle device 10 .
A middle-axle drive gear 86 is fixed onto the transmission shaft 87 , and a middle shaft 83 is rotatably supported parallel to the transmission shaft 87 . An intervention gear 84 is fixed onto one end of the middle shaft 83 so as to engage with the middle-axle drive gear 86 , and a bevel gear 85 is provided onto the other end of the middle shaft 83 . The bevel gear 85 engages with an input bevel gear 90 of a differential 89 which differentially connects the left and right middle axles 25 with each other.
Next, the structure of the front transaxle device 10 will be described in accordance with FIGS. 1 and 2.
In the front transaxle device 10 , an input shaft 14 is rotatably supported by a housing 88 , and connects with the transmission shaft 87 of the middle transaxle device 16 through a propeller shaft 18 , universal joints, and the like.
In the housing 88 , a pinion shaft 95 is disposed forward of the input shaft 14 and supported coaxially with the input shaft 14 . A bevel gear 97 is fixed onto one end portion of the pinion shaft 95 . The input shaft 14 is notched on its periphery so as to form splines, and a front clutch slider 96 is axially slidably but not relatively rotatably disposed around the splines. The pinion shaft 95 is also notched on its periphery so as to form splines, thereby being engaged with or disengaged from the front clutch slider 96 . A detent mechanism 21 is formed in the input shaft 14 to define positions of the front clutch slider 96 , i.e., an engage position where the front clutch slider 96 engages with the pinion shaft 95 , and a disengage position where the front clutch slider 96 disengages from the pinion shaft 95 .
This clutch device 140 is interlocked with a later-discussed drive mode changing lever 130 through a linkage.
In the housing 88 of the front transaxle device 10 , a differential 99 is provided onto the left and right front axles 11 so as to differentially connect the front axles 11 with each other. The differential 99 is constructed similarly to the differential 89 of the middle transaxle device 16 . As shown in FIG. 2, the differential 99 comprises a hollow differential casing 45 , a pinion shaft 46 , pinions 49 , and differential side gears 48 . The differential casing 45 is disposed coaxially with the front axles 11 and rotatably supported by the housing 88 . The pinion shaft 46 is disposed in the differential casing 45 so as to be integrally rotatable with the differential casing 45 . The pinions 49 are disposed oppositely to each other and rotatably supported on the pinion shaft 46 . Each of the differential side gears 48 is fixed onto an inner end of each of the front axles 11 so as to engage with both the pinions 49 .
An input gear 98 , which is a spur gear to receive driving force for the differential 99 , is fixed onto the differential casing 45 .
Next, description will be given on a middle shaft 92 serving as a rotary object which intervenes between the differential 99 and the pinion shaft 95 .
The middle shaft 92 is disposed parallel to a rotational axis of the differential 99 (that is, a rotational axis of the differential casing 45 ). A bevel gear 93 is fixed onto the middle shaft 92 , and is engaged with a bevel gear 97 fixedly provided on the pinion shaft 95 .
The midway portion of the middle shaft 92 is notched on its periphery to form a reduction gear 91 as a spur gear. The reduction gear 91 is engaged with the input gear 98 of the differential 99 .
The middle shaft 92 projects outwardly from the housing 88 . A brake casing 115 is fixedly provided onto the outside of the housing 88 so as to cover the projecting end portion of the middle shaft 92 . A front brake device 100 as a multi-disc type brake is set up around the projecting end portion of the middle shaft 92 between the brake casing 115 and the housing 88 .
In the front brake device 100 , first friction discs 110 are axially slidably but not relatively rotatably provided onto the middle shaft 92 . Second friction discs 111 are slidably but not relatively rotatably engaged with the housing 88 of the front transaxle device 10 . Each of the first friction discs 110 and each of the second friction discs 111 are arranged alternately. A pressure member 113 is provided slidably and coaxially to the middle shaft 92 for pressuring the multi-layered friction discs 110 and 111 against a receiving surface 112 formed at an inner wall of the housing 88 . A piston 114 is provided integrally with the pressure member 113 through a bolt 116 .
The brake casing 115 projects outwardly and coaxially to the middle shaft 92 so as to form a cylindrical portion. The piston 114 is slidably fitted in the cylindrical portion. Hydraulic fluid is to be tightly supplied into a fluid chamber of the cylindrical portion of the brake casing 115 which is formed between an utmost end surface of the cylindrical portion and the piston 114 . By the hydraulic pressure of the fluid supplied into the fluid chamber, the piston 114 slides integrally with the pressure member 113 so as to press the friction discs 110 and 111 against one another, thereby braking the middle shaft 92 .
As shown in FIG. 3 and others, there is formed a substantially ring-shaped gap between an end surface of the piston 114 and the pressure member 113 along the inner peripheral surface of the brake casing 115 . In the gap are arranged a return spring 71 , a collar 72 , and a friction ring 73 , which constitute an automatic gap alignment mechanism 70 to keep a constant stroke of the piston 114 for the braking operation regardless of abrasive reduction of the friction discs 110 and 111 .
The return spring 71 is a ring-shaped spring, which is semicircular in its radial section. The major portion of the spring 71 is inserted into a ring-like groove 74 , which is formed on an end surface of the piston 114 around the middle shaft 92 so as to face toward the discs 110 and 111 . An apex portion of the spring 71 in its sectionally semicircular shape projects toward the discs 110 and 111 so as to abut against the collar 72 . Thus, the spring 71 is sandwiched between the piston 114 and the collar 72 . The collar 72 is slidable on the inner peripheral surface of the cylindrical portion of the brake casing 115 . The friction ring 73 has outward biasing force in the radial direction and is fitted to an inner peripheral face of the brake casing 115 . Therefore, the friction ring 73 is slidable on the inner peripheral surface of the cylindrical portion of the brake casing 115 against frictional resistance between the friction ring 73 and the inner peripheral face of the brake casing 115 . This friction resistance applied onto the friction ring 73 is larger than the spring force of the return spring 71 and smaller than the hydraulic pressure applied on the piston 114 .
Referring to FIG. 3, the friction discs 110 and 111 are new, i.e., they are not worn. The total clearance between the friction discs 110 and 111 is of a length A. Therefore, a stroke of length A is required for the piston 114 to bring the friction discs 110 and 111 into contact with one another. An original amount of hydraulic fluid is filled in the fluid chamber so that the utmost end of the piston 114 is located at an original brake-released position P. At this time, the return spring 71 expands so as to generate a gap of the length A between the end surface of the piston 114 and the collar 72 . The retaining ring 73 is sandwiched between the collar 72 and the pressure member 113 .
For the braking operation of the front brake device 100 , hydraulic fluid is supplied into the fluid chamber in the brake casing 115 so as to push the pressure member 113 toward friction discs 110 and 111 . As shown in FIG. 4, when the piston 114 is moved at a stroke of length A, the friction discs 110 and 111 are brought into engagement so that the middle shaft 92 starts to be braked. During this stroke of the piston 114 , the return spring 71 is compressed between the collar 72 and the piston 114 so as to absorb the pressure force of the piston 114 , thereby maintaining the positions of the collar 72 and the friction ring 73 . Therefore, the gap of the length A between the piston 114 and the collar 72 is diminished, and a gap of the length A is generated between the friction ring 73 and the pressure member 113 .
For releasing the middle shaft 92 from its brake condition shown in FIG. 4, fluid is drained from the fluid chamber in the cylindrical portion of the brake casing 115 so that the spring 71 returns to its expanded condition, thereby locating the piston 114 at the original brake-releasing position P. The pressure member 113 follows the piston 114 , thereby disengaging the friction discs 110 and 111 . Consequently, the front brake device 100 returns to the state as shown in FIG. 3 .
Description will be given on the action of the automatic gap alignment mechanism 70 corresponding to the abrasive reduction of the friction discs 110 and 111 in accordance with FIGS. 5 to 7 .
Referring to FIG. 5, friction discs 110 ′ and 111 ′ are abraded versions of friction discs 10 and 111 . The total abrasive reduction of the discs 110 ′ and 111 ′ in the axial direction of the middle shaft 92 is of a length B. Therefore, even if the same amount of fluid as that in the situation of FIG. 4 is supplied so as to move the piston 114 at a stroke of length A from its original brake-released position P, the friction discs 110 ′ and 111 ′ are still disengaged. To bring the discs 110 ′ and 111 ′ into engagement, the piston 114 requires an additional stroke of length B. In other words, the piston 114 at the original brake-released position P requires a stroke of lengths A+B for braking.
However, in the situation as shown in FIG. 5, the pressure member 113 is allowed to further move because of the additional clearance among the friction discs 110 ′ and 111 ′ generated by their abrasion. Also, the collar 72 abuts against the end surface of the piston 114 because of the compression of the spring 71 . Therefore, as shown in FIG. 6, increased fluid is supplied so that the piston 114 is completely moved together with the pressure member 113 at the stroke of length A+B from its original brake-released position P. During the movement of the piston 114 and the pressure member 113 , the end surface of the piston 114 pushes the collar 72 together with the friction ring 73 against the friction resistance between the friction ring 73 and the brake casing 115 . Therefore, the collar 72 and the friction ring 73 are shifted from their original positions as shown in FIGS. 3 and 4.
Referring to FIG. 7, when the hydraulic pressure on the piston 114 is released, the friction ring 73 remains at its new position shifted from its original position by its frictional resistance and the spring 71 expands between the collar 72 and the piston 114 . Therefore, the piston 114 retreats only a stroke of length A by the expansion of the spring 71 . The pressure member 113 follows the retreating of the piston 114 , thereby disengaging the friction discs 110 ′ and 111 ′. Consequently, a new brake-released position Q of the utmost end of the piston 114 is shifted from its original brake-release position P. The required stroke of the piston 114 in addition to the stroke of length A in the next braking operation of the front brake device 100 is just as much as the new abrasive reduction of the discs 110 and 111 .
Thus, on every braking action of the piston 114 , the friction ring 73 is shifted so as to counter the additional clearance caused by the abrasion of the friction discs 110 ′ and 111 ′, thereby shifting the brake-release position of the piston 114 toward the discs 110 ′ and 111 ′. Strictly speaking, the required stroke of the piston 114 in every braking operation is of the length A+B. However, in each braking operation, the additional stroke of length B as much corresponding to the abrasive reduction of the friction discs 110 ′ and 111 ′ is extremely small, thereby being able to be ignored in measurement. Therefore, it may be said that the stroke of the piston 114 required for every braking operation is substantially of the length A. In this meaning, the stroke of the piston 114 required for braking is kept constant regardless of the abrasive reduction of the friction discs 110 ′ and 111 ′. Consequently, the swift response of the front brake device 100 can be maintained for a long period of use.
Referring to FIG. 8, in the front transaxle device 10 ′, a brake device 100 ′ is disposed at the pinion shaft 95 ′, instead of the front brake device 100 disposed at the middle shaft 92 . Description will be given on this structure.
In the brake device 100 ′, first friction discs 110 are fit onto the pinion shaft 95 ′ such that the first friction discs 110 cannot rotate with respect to the pinion shaft 95 ′. Second friction discs 111 are engaged with the housing 88 ′. Each of the first friction discs 110 and each of the second friction discs 111 are arranged alternately. The piston 119 ′ is provided to press the friction discs 110 and 111 . The piston 119 ′ is formed into a ring-shape, and is fluid-tightly fitted with a groove formed at an inner wall of the housing 88 ′ such that the piston 119 ′ can be displaced in parallel with the pinion shaft 95 ′. An oil path 121 is formed at the groove so as to apply hydraulic force onto one end face of the piston 119 ′, thereby operating the piston 119 ′ hydraulically. The oil path 121 is connected to an oil hydraulic circuit 120 which will be described below.
In this structure, the piston 119 ′ is driven by the oil supplied from the oil hydraulic circuit 120 in such a direction as to project and to press the friction discs 110 and 111 , thereby braking the pinion shaft 95 ′ by friction.
Next, the structure in the multi-wheel-drive vehicle to operate the front and rear brake devices 100 and 22 for braking by manipulation of the above-mentioned brake pedal will be described in accordance with FIG. 9 .
The brake pedal 19 constituting the brake operating means in the present embodiment is connected with the rear brake devices 22 and the front brake device 100 through the oil hydraulic circuit 120 shown in FIG. 9 . The oil hydraulic circuit 120 comprises a master cylinder 101 to discharge oil for the brake devices 22 and 100 , an oil tank 102 for supplying oil to the master cylinder 101 , a filter 103 for removing impurities from the oil, an oil path 105 for leading oil from the master cylinder 101 to the front and rear brake devices 100 and 22 , and the like.
The brake pedal 19 is supported rotatably, and an end of a rod 106 is connected to the midway portion of the brake pedal 19 . The other end of the rod 106 is fixed on a piston 107 disposed in the master cylinder 101 . A biasing spring 108 , which also serves as a recovering spring for the brake pedal 19 , is disposed in the master cylinder 101 .
The filter 103 and a manual valve 104 are disposed at a midway portion of the circuit for supplying oil from the oil tank 102 into the master cylinder 101 . The manual valve 104 is interlocked with the rod 106 such that the manual valve 104 opens the circuit when the brake pedal 19 is not depressed, and that the manual valve 104 is switched by the rod 106 and shuts the circuit when the brake pedal 19 is depressed thereby preventing oil from back-flowing in the circuit when the rod 106 pushes the piston 107 .
In this structure, when an operator depresses the brake pedal 19 , the piston 107 is pushed through the rod 106 , and the master cylinder 101 discharges the oil.
The discharged oil is led into the oil path 105 and is divided into two branches. The oil in one branch runs to each of the rear brake devices 22 , thereby applying braking force onto the rear axles 8 . The braking force is transmitted to the middle axles 25 connected to the rear axles 8 through the drive shaft 17 and the like, thereby also braking the middle axles 25 . The oil in the other branch is led into the front brake device 100 to make the piston 114 in the front brake device 100 press against friction discs 110 and 111 , thereby applying braking force onto the front axles 11 through the middle shaft 92 .
Description will be given on the structure in the multi-wheel-drive vehicle to transmit the power from the engine 3 to the wheels 9 , 12 , and 26 .
As shown in FIG. 1, the transmission 13 provided in the rear transaxle device 4 transmits the power from the engine 3 to the rear axles 8 to drive the rear wheels 9 , and also transmits the power to the middle transaxle device 16 through the drive shaft 17 to drive the middle wheels 26 through the middle axles 25 .
In other words, the power from the transmission 13 branches to the rear axles 8 and the middle axles 25 , thereby constantly driving the rear wheels 9 and the middle wheels 26 (four wheels in total).
Furthermore, the power, which is led from the engine 3 into the middle transaxle device 16 , drives the input shaft 14 in the front transaxle device 10 constantly through the transmission shaft 18 .
The earlier-discussed clutch device 140 is disposed at the input shaft 14 . As shown in FIG. 9, the drive mode changing lever 130 is provided at the appropriate portion of the vehicle to operate the clutch device 140 , and the drive mode changing lever 130 is shiftable among a 4-wheel-drive position and a 6-wheel-drive position (two positions in total). The drive mode changing lever 130 is linked with the front clutch slider 96 in the clutch device 140 such that the clutch device 140 is engaged when the drive mode changing lever 130 is located at its 6-wheel-drive position (as shown by ‘6WD’ position in FIG. 9) and that the clutch device 140 is disengaged when the drive mode changing lever 130 is located at its 4-wheel-drive position (as shown by ‘4WD’ position in FIG. 9 ).
Therefore, when the drive mode changing lever 130 is located at its 6-wheel-drive position, the clutch device 140 is engaged to drive the front transaxle device 10 such that the front wheels 12 are driven through the front axles 11 . Because the four wheels of the middle wheels 26 and the rear wheels 9 are driven as described above at this time, the vehicle is put into 6-wheel-drive mode and all six wheels are driven.
On the other hand, when the drive mode changing lever 130 is located at its 4-wheel-drive position, the clutch device 140 is disengaged and the power from the transmission 13 is shut off such that the front wheels 12 are not driven. In this case, the vehicle is put into 4-wheel-drive mode and only the middle wheels 26 and the rear wheels 9 , four wheels in total, are driven.
The above-mentioned structure is an example and other embodiments may be given. For instance, instead of the structure where an oil hydraulic circuit 120 is used, a structure which will be described below may apply.
An oil hydraulic circuit 120 ′ shown in FIG. 10, which is used in this modification, is of the structure that a manual valve 150 which is switchable among two positions is provided at the midway of a path for supplying oil of the master cylinder 101 for the front brake device 100 in the oil hydraulic circuit 120 ′ in the brake system.
A brake mode changing lever 155 serving as a brake mode changing means is provided at the operator's section in the vehicle, and the manual valve 150 is interlocked with the brake mode changing lever 155 .
The brake mode changing lever 155 is shiftable according to an operator's manipulation between a front-rear-brake position FRb and a rear-brake position Rb.
When the brake mode changing lever 155 is located at its front-rear-brake position FRb, the manual valve 150 is opened. Thus, when the brake pedal 19 is depressed, oil from the master cylinder 101 is supplied into both the rear brake devices 22 and front brake device 100 . In this case, the vehicle is put into front-rear-brake mode wherein the rear and front brake devices 22 and 100 are put into action.
On the other hand, when the brake mode changing lever 155 is located at its rear-brake position Rb, the manual valve 150 is closed. Thus, when the brake pedal 19 is depressed, oil from the master cylinder 101 is not supplied into the front brake device 100 , but into the rear brake devices 22 . In this case, the vehicle is put into the rear-brake mode wherein only the rear brake devices 22 are put into action.
Furthermore, the brake pedal 19 is linked with above-mentioned drive mode changing lever 130 through a linkage so as to make the drive mode changing lever 130 located at its 6-wheel-drive position when the brake pedal 19 is depressed.
The action of the above structure will be described. When the brake mode changing lever 155 is located at its rear-brake position Rb and the drive mode changing lever 130 is located at its 4-wheel-drive position 4WD, and when the brake pedal 19 is depressed, the manual valve 150 is closed and only the rear brake devices 22 are put into action. However, because the drive mode changing lever 130 is switched into its 6-wheel-drive position 6WD at the time when the brake pedal 19 is depressed and the clutch device 140 linked with the drive mode changing lever 130 is engaged, the braking force which the rear brake devices 22 apply onto the rear axles 8 and the middle axles 25 is also transmitted to the front axles 11 through the propeller shaft 18 and the like, thereby also braking the front axles 11 .
Therefore, though the power from the engine 3 is transmitted to only the rear axles 8 and the middle axles 25 such that four wheels are driven, braking force generated by only rear brake devices 22 is applied onto not only the rear axles 8 and the middle axles 25 but also the front axles 11 such that all the six wheels can be braked.
In this structure, changing among 4-wheel-drive mode and 6-wheel-drive mode as the occasion arises is easy by engaging and disengaging the clutch device 140 by shifting the drive mode changing lever 130 .
If the vehicle is put into the 4-wheel-drive mode and the brake pedal 19 is depressed in the rear-brake mode, braking force generated by the rear brake devices 22 is transmitted to the front axles 11 by the linkage between the brake pedal 19 and the clutch device 140 . Though the front brake device 100 in the front transaxle device 10 is out of action, not only the rear wheels 9 and the middle wheels 26 but also the front wheels 12 are contributing to the braking of the vehicle. Thus, by putting the vehicle into the rear-brake mode, while good braking performance can be maintained, abrasion of the front brake device 100 can be prevented.
Of course, the vehicle can be put into the front-rear-brake mode which is effective when strong braking force is frequently desirable. In this mode, the front wheels 12 are braked by the front brake device 100 and the rear wheels 9 and the middle wheels 26 are braked by the rear brake devices 22 . Good braking performance is achieved by applying braking force onto the rear wheels 9 , the middle wheels 26 , and the front wheels 12 (all six wheels), and the rear brake devices 22 are protected from overload, such that heating and abrasion can be minimized.
Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form may be changed in the details of construction and the combination and arrangement of parts may be resorted without departing from the spirit and the scope of the invention as hereinafter claimed.
For example, the front transaxle device in the present invention can apply not only to a six-wheel-drive vehicle as described in above embodiment but also to a multi-wheel-drive vehicle wherein eight or more wheels are driven.
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A multi-wheel-drive vehicle has at least six wheels, a transmission with a first brake, and a transaxle device for the front drive wheels. The transaxle device includes a drive axle, an input shaft perpendicular to the drive axle for receiving power from the transmission, a drive train connecting the drive axle to the input shaft, a second brake, and a clutch device on the input shaft. The transaxle device may include a pair of drive axles connected by a differential unit. The clutch device can selectively isolate the drive axles from the rotation of the input shaft. Further, the clutch device is engaged when the first brake is applied. Additionally, the first and second brakes may be connected such that their operation may be synchronized.
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BACKGROUND TO THE INVENTION
This invention relates to apparatus for, and a method of, stacking and collecting labels, and in particular to automatic stacking and collecting apparatus for individual paper or paper laminate labels produced on a web printing machine.
A known label stacking apparatus includes a plurality of sets of suction discs. Each set of suction discs receives successive labels from a respective stream of labels fed thereto from a web printing machine by a respective pair of suction belts. The suction discs hold the leading edges of the labels by suction through holes in their peripheral edges. The discs rotate the labels through 90°, after which the labels are stripped off by an intercepting horizontal table. The stacks of labels are then removed by hand for a subsequent banding operation.
This known apparatus has a major disadvantage, namely that the stacks must be manually removed for banding, or for putting into a ram punching machine. This disadvantage is exacerbated as the operating speed of the apparatus increases; which, with a modern high-speed web printing machine, can be a serious limitation. Another disadvantage of this known apparatus is that it cannot handle long labels (that is to say labels having a length greater than about 160 millimeters).
The aim of the invention is to provide apparatus for, and a method of, stacking and collecting labels which do not suffer from the disadvantages mentioned above, even when the stacking and collecting is done downstream of a high-speed web printing machine, and the labels concerned are long.
SUMMARY OF THE INVENTION
The present invention provides apparatus for stacking and collecting labels, the apparatus comprising feed means for continuously feeding at least one stream of individual labels, a movable support assembly for supporting a respective stack of labels corresponding to the or each stream fed thereto by the feed means, and a fixed support assembly for receiving the or each stack of labels from the movable support assembly, the movable support assembly being movable relative to the fixed support assembly firstly to transfer the or each stack of labels to the fixed support assembly, and secondly to push the or each stack of labels off the fixed support assembly, wherein an intermediate support assembly is provided for supporting labels whilst the movable support assembly pushes the or each stack off the fixed support assembly.
The movable support assembly of this apparatus thus acts as a support for the stack(s) of labels as these are delivered by the feed means, and as means for automatically pushing the stack(s) away from the apparatus for banding. Whilst the movable support assembly carries out the pushing step, the intermediate support assembly intercepts the flow of labels, so that the apparatus can operate continuously with an upstream web printing machine.
Advantageously, the apparatus further comprises a transfer carriage positioned adjacent to the fixed support assembly in such a position as to receive the or each stack of labels as it is pushed off the fixed support assembly by the movable support assembly.
The feed means may be constituted by a suction drum including a respective set of suction discs for each stream of labels, each suction disc being provided with at least one series of suction holes in its periphery.
Advantageously, the movable support assembly is constituted by a plurality of parallel, equi-spaced plates, said plates being mounted at one end of a common support arm, the other end of the support arm being pivotally mounted in the housing of the apparatus. Preferably, the fixed support assembly is constituted by a plurality of parallel, equi-spaced plates, the plates of the fixed support assembly being so positioned that the plates of the movable support assembly can pass therebetween. Conveniently, the plates of both assemblies have convex upper edges.
In a preferred embodiment, each plate of the fixed support assembly is provided with an upright extending generally at right-angles thereto and at one end thereof. The apparatus may further comprise a respective stripping finger associated with the or each stream of labels, the or each stripping finger being positioned adjacent to the suction drum so as to strip the labels of the associated stream away from the drum. In this case, the or each stripping finger is spaced by substantially 150° around the periphery of the suction drum from the point where the associated stream of labels meets the suction drum; and the arcuate span between the two end suction holes of each series of suction holes in the suction discs is equal to the distance between the point where the labels are stripped away from the suction drum by the associated stripping finger and the uprights of the fixed support assembly. This permits the labels to be placed on the stack(s) rather than being thrown, and so leads to a uniformity or stacking irrespective of the speed of the upstream machine. Moreover, because the suction holes extend round an arc of each of the suction discs, the labels are held over a considerable distance as they "roll" over the suction discs, so that the apparatus can also handle long labels.
Advantageously, the common support arm of the movable support assembly is reciprocable in the direction of its longitudinal axis by means of a ram. This ram can be used to move the movable support assembly relative to the fixed support assembly so as to transfer the stack(s) of labels to the fixed support assembly. Preferably, said ram is an air-operated, pressure-intensified oil dosing ram which is extended by air operation and retracted incrementally by doses of oil.
The movable support assembly may be rotatable about said other end of the support arm by a pneumatic ram assembly. This ram assembly can be used to push the stack(s) of labels off the fixed support assembly. Preferably, the pneumatic ram assembly is constituted by a long-stroke pneumatic ram and a short-stroke pneumatic ram.
The intermediate support assembly may be constituted by a bar and a respective counting finger aligned with the or each stream of labels, the arrangement being such that the or each counting finger is interposed between the feed means and the associated previously-positioned stack of labels when a predetermined number of labels have been fed to said stack. Advantageously, the or each counting finger is provided with a suction hole in the upper surface for retaining the first label fed thereto after the predetermined number of labels has been fed to the associated stack.
The apparatus may further comprise an electronic batch counter for counting the number of labels fed to the or each stack. Advantageously, the bar is rotatable about its longitudinal axis by a pneumatic ram, said pneumatic ram being controlled by a signal from the electronic batch counter. Preferably, the bar is reciprocable towards, and away from, the feed means by a further pneumatic ram.
The invention also provides a method of stacking and collecting labels, the method comprising the steps of feeding at least one stream of individual labels to a movable support assembly, the feed means being such as to deposit successive labels of the or each stream in a respective stack on the movable support assembly, moving the movable support assembly in a first direction relative to a fixed support assembly so that the or each stack of labels is transferred to the fixed support assembly, and moving the movable support assembly in a second direction relative to the fixed support assembly to push the or each stack of labels off the fixed support assembly.
The movable support assembly may be moved linearly with respect to the fixed support assembly in said first direction, and may be moved arcuately with respect to the fixed support assembly in said second direction.
Advantageously, the method further comprises the step of positioning an intermediate support assembly in the path of the labels as they are moved towards the movable support assembly when a predetermined number of labels have been delivered to the or each stack, whereby subsequently fed labels of the or each stream form a respective new stack on the intermediate support assembly. In this case, the method may further comprise the step of withdrawing the intermediate support assembly after the movable support assembly has pushed the or each stack of labels off the fixed support assembly, whereby the or each new stack carried by the intermediate support assembly is transferred to the movable support assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
Apparatus for stacking and collecting labels and constructed in accordance with the invention will now be described in detail, by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a schematic side elevation of the apparatus;
FIG. 2 is an end elevation of the apparatus; and
FIGS. 3a to 3g are schematic side elevations showing successive operating positions of the apparatus.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring to the drawings, FIGS. 1 and 2 show apparatus for collecting and stacking labels, the apparatus being positioned downstream of machinery (not shown) used to print the labels to cut the labels to size. The apparatus comprises a plurality of suction belts 1 (only one of which can be seen in FIG. 1). Each suction belt 1 carries a respective stream of printed and cut labels from the upstream machinery to a suction drum 2. The suction drum 2 has a plurality of sets of hollow suction discs 3 (only one of which can be seen in FIG. 1). Each set of suction discs 3 is aligned with a respective suction belt 1 so as to pick up the labels of the associated stream as they leave the suction belt. Typically, there are two suction discs 3 in each set, the discs of each set being associated with a respective manifold 3a (see FIG. 2). Each suction disc 3 is formed with a plurality (say three) of series of suction holes (not shown) in its circumferential edge. The suction holes of each of the suction discs 3 extend over an arc of 160 millimeters length, so that the labels are held to the suction discs over a considerable distance as they "roll" round the suction discs. This enables the apparatus to handle long labels (that is to say labels longer than about 160 millimeters). The hollow interiors of the manifolds 3a of the suction discs 3 are connected to a vacuum pump (not shown), as are the suction belts 1.
The suction discs 3 are arranged to carry the labels through 150°, and then to deposit them in stacks as described below. Accordingly, stripping fingers 4 (only one of which can be seen in FIG. 1) are positioned to strip the leading edges of the labels once the labels have been carried through 150°. The stripping fingers 4 are arranged between adjacent support discs 3 of each set. As the labels are stripped away from their sets of suction discs 3, they are precisely deposited on a movable support assembly 5. This assembly 5 is constituted by a plurality of equi-spaced parallel plates 6 (only one of which can be seen in FIG. 1), each of which has a convex upper support edge 6a. The plates 6 are attached to a support bar 7, which in turn is mounted on one end of a support arm 8. The other end of the support arm 8 is pivotally mounted, at 9, to the frame 10 of the apparatus. The movable support assembly 5 can be rotated about the pivot 9 by a compound pneumatic ram system constituted by a long-stroke ram 11 and a short-stroke ram 12. The cylinders 11a and 12a of the rams 11 and 12 are pivotally mounted on the frame 10, and their piston rods 11b and 12b are pivotally attached to the support arm 8. The support arm 8 is attached to a pair of tied racks 8a (only one of which is shown), and is reciprocable by a ram 13 to raise and lower the movable support assembly 5. The ram 13 is an air-on-oil ram, lowering of the support arm 7 being effected by an air-operated, pressure-intensified oil dosing arrangement. The tied racks 8a cooperate with pinions 8b to ensure that the support arm 8 moves in parallelism.
The movable support assembly 5 cooperates with a fixed support assembly 14. This assembly 14 is constituted by a plurality of equi-spaced parallel plates 15 (only one of which can be seen in FIG. 1), each of which has a convex upper support edge 15a and an upright 15b. The uprights 15b define a back stop against which the stacks of labels can rest. The convex support edges 15a and the convex support edges 6a have different radii of curvature. The plates 15 are positioned so that the plates 6 of the movable support assembly 5 can pass therebetween. This enables stacks of labels deposited on the movable support assembly 5 to be transferred to the fixed support assembly 14 (as is described below). After the stacks of labels have been transferred to the fixed support assembly 14, they are pushed by the movable support assembly 5 on to a transfer carriage 16, as is described in detail below.
In order that a predetermined number of labels may be positioned in each of the stacks, count fingers 17 (only one of which can be seen in FIG. 1) are provided. A respective count finger 17 is provided for each stack, and the count fingers are all mounted on a common equipment bar 18. The bar 18 is rotatable about its central longitudinal axis by means of a pneumatic ram 19. The bar 18 is also movable into, and out of, an operating position by a pneumatic ram 20. The ram 20 is effective to move the bar 18 towards, and away from, the suction drum 2. During this reciprocal movement, the bar 18 is guided between rails (not shown), and is connected to the ram 20 by a rack 20a and a pinion 20b. The operation of the count fingers 17 is controlled by an electronic batch counter (not shown).
The apparatus also includes a plurality of stack separator plates 21 (only one of which can be seen in FIG. 1). These plates 21 extend between the stacks of labels, and are arranged to oscillate transversely, thereby ensuring that the labels in all the stacks have their lateral edges accurately aligned. The plates 21 are mounted on a bar 22 which is movable backwards and forwards by an oscillating mechanism 23.
The operation of the stacking apparatus will now be described with reference to FIGS. 3a to 3g. FIG. 3a shows the apparatus in the position in which stacks 24 (only one of which can be seen) have been transferred from the movable support assembly 5 to the fixed support assembly 14, the movable support assembly is in an intermediate position, and the count fingers 17 have been moved forward to intercept the flow of labels and start new stacks 24'. This movement of the count fingers 17 is initiated by a control signal from the electronic batch counter, which actuates the ram 19 to pivot the bar 18 so as to move the count fingers into the position shown in FIG. 3a. The electronic batch counter is arranged to emit the control signal after it has counted a predetermined number of labels (say 1000).
The movable support assembly 5 is then actuated to push the stacks 24 along the plates 15 of the fixed support assembly 14, and on to the transfer carriage 16 (see FIG. 3b). This is accomplished by rotating the assembly 5 about its pivot 9 by the long-stroke ram 11. The short-stroke ram 12, which at this stage is fully extended, takes no part in this movement. At this stage, the labels delivered by the suction drum 2 pile up on the count fingers 17, forming the new stacks 24'. The stacks 24 can then be moved laterally to one or more banding modules, after which they are removed for transportation.
The movable support assembly 5 is then retracted a short distance to provide an operating clearance between the plates 6 and the transfer carriage 16 (see FIG. 3c). At the same time, the count fingers 17 are retracted. The part-way retraction of the movable support assembly 5 is effected by the retraction of the short-stroke ram 12; and the count fingers 17 are retracted (together with the bar 18) by retracting the ram 20.
As the suction drum 2 feeds more and more labels on to the stacks 24', the movable support assembly 5 is lowered (see FIG. 3d). At the same time, the count fingers 17 are raised. The assembly 5 is lowered by the ram 13, air-operated, pressure-intensified oil doses being fed to the ram 13 in a controlled manner in dependence upon signals received from the electronic batch counter. In this way, the movable support assembly 5 is lowered at a controlled rate which is proportional to the rate of stack growth. The count fingers 17 are raised by rotating the bar 18 using the ram 19.
The count fingers 17 are then moved back towards the suction drum 2, whilst the movable support assembly 5 continues to be lowered until the convex upper edges 6a of its plates 6 lie below the convex upper edges 15a of the plates 15 of the fixed support assembly 14 (see FIG. 3e). The stacks 24' then rest on the fixed support assembly 14. The count fingers 17 are moved back towards the suction drum 2 by the ram 20.
The movable support assembly 5 is then rotated fully down by retracting the long-stroke ram 11 (see FIG. 3f). The assembly 5 is then raised relative to its support arm 8 by fully extending the ram 13 (see FIG. 3g). This brings the movable support assembly 5 into alignment with the stacks 24'. This step is immediately followed by a partial rotation of the movable support assembly 5, about the pivot 9, to bring the apparatus into the start position. This is accomplished by extending the short-stroke ram 12. The apparatus is now in position to repeat the cycle upon receipt of the control signal from the batch counter.
It should be noted that the apparatus is such that each label is held on the suction drum 2 by suction through series of holes in the associated sets of suction discs 3, so that it is rotated through 150°, and deposited precisely to the back of a pocket formed by the previously-delivered label and the back stop defined by the uprights 15b of the plates 15 of the fixed support assembly 14. The arcuate span of the first and last holes in each series of holes is arranged to be equal to the distance from the point where a label is stripped from the suction discs 3 (by the stripping fingers 4) to the back stop. Suction is applied to each hole of a series consecutively at the transfer point at the top of the associated suction disc 3 (that is to say at the point where a label is transferred to the suction drum 2 from the upstream suction belts 1), and cut off 150° later at the stripping point. This is accomplished by a stationary annular valve (not shown). As a result of this arrangement, the labels are laid on their stacks, rather than being thrown against the back stop.
It will be apparent that the apparatus described above could be modified in a number of ways. For example, depending upon the width of the labels, each stream of labels could be handled by two or more suction belts (and accordingly by two or more sets of suction discs).
Although the apparatus described above is used to stack and collect labels (particularly paper labels or paper laminate labels), it will be appreciated that it could also be used to stack and collect other similar flat flexible articles, and the term "labels" should be construed accordingly throughout this specification.
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Apparatus for stacking and collecting labels includes a suction drum for continuously feeding at least one stream of individual labels to a movable support assembly. The movable support assembly supports a respective stack of labels corresponding to the or each stream fed thereto by the suction drum. A fixed support assembly is provided for receiving the or each stack of labels from the movable support assembly. The movable support assembly is movable relative to the fixed support assembly, firstly to transfer the or each stack of labels to the fixed support assembly, and secondly to push the or each stack of labels off the fixed support assembly. An intermediate support assembly is provided for supporting labels while the movable support assembly pushes the or each stack off the fixed support assembly.
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BACKGROUND
There is a need for coatings which can be used to apply to plastic substrates such as of polysulfone, polyester and polycarbonate resins to act as a barrier by sealing the surface and to enhance resistance to scratching. Plastic substrates are useful in cookware for use in microwave ovens, where such coatings may be particularly desirable.
Known coatings, including epoxy resins, urea formaldehyde crosslinkers and polytetrafluoroethylene (PTFE) generally require temperatures such as 204° C. to cure. Curing temperatures as high as this are unacceptable for certain kinds of plastic substrates. Furthermore, it is generally desirable to use lower cure temperatures when possible.
SUMMARY
The present invention provides a coating composition consisting essentially, in percent by weight of (A), (B), (C), (D) plus (E), of a dispersion in a liquid organic media of about:
(A) 10-50% of an epoxy resin containing, on the average, two terminal 1,2-epoxy groups per molecule and having an epoxy equivalent weight of 750-5000;
(B) 1-20% of a melamine formaldehyde resin;
(C) 1-10% particulate polymer polymerized or copolymerized from monomers selected from one or more monoethylenically unsaturated hydrocarbon monomers and hydrocarbon ether monomers, said monomers being completely substituted with fluorine atoms;
(D) 0.2-5% citric acid; and
(E) the balance being said liquid organic media.
Preferably, the fluorocarbon resin is PTFE. A preferred form of fluorocarbon resin is irradiated micropowder such as that described in U.S. Pat. No. 4,029,870--Brown (1977).
DETAILED DESCRIPTION
The various ingredients used in the present invention are blended together using ordinary mixing equipment.
The fluorocarbon polymers used are those of hydrocarbon monomers completely substituted with fluorine atoms. Included in this group are perfluoroolefin polymers such as polytetrafluoroethylene (PTFE) and copolymers of tetrafluoroethylene and hexafluoropropylene in all monomer unit weight ratios, and copolymers of tetrafluoroethylene and perfluoroalkyl vinyl ethers. Mixtures of these can also be used.
The epoxy resins to be utilized in the present invention are commonly known in the art. One class of such resins has the generalized formula ##STR1## wherein R is an alkylene group of 1-4 carbon atoms and n is an integer from 1-12. The epoxy resins utilized in this invention contain an average of two terminal 1,2-epoxy groups per molecule and are in the epoxy equivalent weight range of 750-5000, preferably 1500-4000. They can also contain substituted aromatic rings.
One such preferred epoxy resin is Epon® 1004 sold by Shell Chemical Co. where R is isopropylidene, the average value of n is 5, having an epoxy equivalent weight of 875-1025, with an average of about 950±50. The epoxy equivalent weight is defined as the grams of resin containing 1 gram-equivalent of epoxide as measured by ASTM-D-1652. The coating composition containing "Epon 1004" affords a glossy, flexible, chemically-resistant film. Another preferred epoxy resin is "Epon 1007" where R is iopropylidene, the average value of n is 11, having an epoxy equivalent weight of 2000-2500, with an average of about 2175±50.
Nitrogen resin crosslinker are well known. They are the alkylated products of amino-resins prepared by the condensations of at least one aldehyde with at least one of urea, benzoguanamine N,N'-ethyleneurea, dicyandiamide, and aminotriazines such as melamines. Among the aldehydes that are suitable are formaldehyde, revertible polymers thereof such as paraformaldehyde, acetaldehyde, crotonaldehyde, and acrolein. Preferred are formaldehyde and revertible polymers thereof. The amino-resins are alkylated with at least one and up to and including six alkanol molecules containing 1-6 carbon atoms. The alkanols can be straight chain, branches or cyclic.
Nitrogen resins preferred for the invention are melamine formaldehyde resins. The melamine portions are preferably partially methylated melamines, partially butylated melamines, hexaethoxymethylmelamine, hexamethoxymethylmelamine, dimethoxytetraethoxymethylmelamine, dibutoxytetramethoxymethylmelamine, hexabutoxymethylmelamine, and mixtures thereof. Commercially available preferred melamine formaldehyde resins include the following products of American Cyanamid Co.:
Cymel® 303 highly methylated melamine
Cymel® 1116 highly methylated and ethylated melamine
Cymel® 1130 highly butylated melamine
Cymel® 1156 highly butylated melamine
"Beetle 65" melamine formaldehyde
In the claims, the term "consisting essentially of" means not including other ingredients in amounts which change the basic and novel characteristics of the invention, including providing low-temperature curing barrier and abrasion resistant coatings. Other commonly utilized additives such as coalescing aids, flow-control agents, plasticizers, pigments and the like can be added in the usual amounts, if this appears necessary or desirable.
It has surprisingly been found that the addition of citric acid in accordance with the invention permits curing these coatings at temperatures low enough to permit them to be used on polysulfone, polyester or polycarbonate substrates.
In the examples, as elsewhere herein, percentages and proportions are by weight.
EXAMPLE 1
A coating compositon is prepared as follows:
Portion 1
PTFE micropowder irradiated at 7.5 megarads and subsequently heated at 260° C.
Portion 2
______________________________________"Epon 1007" (epoxy resin from 14.84%Shell Chemical Co.)Butyl Acetate 33.79%Cellosolve acetate 12.68%n-Butyl alcohol 5.28%Methyl isobutyl ketone 3.58%Red iron oxide 1.27%#19 Brown pigment (iron, aluminum 3.91%and titanium oxidefrom Shepherd ChemicalCo.)Carbon black .42%Calcined alumina 9.19%Portion 1 4.52%"Triton X-100" (octyl phenol poly- .52%ether alcohol surfactantfrom Rohm & Haas Co.)"Cymel 301" (melamine-formaldehyde 7.00%resin from AmericanCyanamid)Citric acid 3.00%______________________________________
Portion 1 was prepared in an oven where the temperature is monitored using a thermocouple placed half-way down in the layer of powder. When the temperature reached 260° C. it was maintained for 15 minues.
Portion 2 was prepared by milling all the ingredients, except for the "Cymel 301" resin and citric acid, in a pebble mill for 20 hours. At the conclusion of this time, the "Cymel 301" resin and citric acid were added and milling continued for an additional 30 minues. The resulting dispersion was sprayed onto polyester, polysulfone and polycarbonate substrates and baked 20 minutes in a 107° C. oven. The resulting finishes were tough, scratch resistant and abrasion resistant, and exhibited moderate release properties.
EXAMPLE 2
______________________________________"Epon 1007" epoxy resin 14.84%Butyl acetate 33.79%Cellosolve acetate 12.68%n-Butyl alcohol 5.28%Methyl isobutyl ketone 3.58%Red iron oxide 1.27%#19 Brown pigment 3.91%Carbon black .42%Calcined alumina 9.19%Portion 1 of Example 1 4.52%Triton X-100 .52%"Beetle-65" (Melamine-formaldehyde 7.00%resin from AmericanCyanamid Co.)Citric acid 3.00%______________________________________
The ingredients, except for the "Beetle-65" resin and citric acid, were placed in a pebble mill and milled for 20 hours. At the conclusion of this time, the "Beetle-65" resin and citric acid were added to the mill and milling was continued for an additional 30 minutes. The dispersion was sprayed onto a polysulfone substrate and baked for 10 minutes in a 107° C. oven. The resulting films were tough, scratch resistant and exhibited moderate relates properties.
EXAMPLE 3
A coating composition was prepared as follows:
______________________________________"Epon 1007" epoxy resin 16.06%Butyl acetate 33.77%Cellosolve acetate 12.47%n-Butyl alcohol 5.26%Methyl isobutyl ketone 3.56%Red iron oxide 1.25%#19 Brown pigment 3.92%Carbon black .44%Calcined alumina 5.37%Portion 1 of Example 1 9.00%"Cymel 301" resin 6.93%Citric acid .97%Dow Corning 510 silicone fluid 1.00%______________________________________
The ingredients except for the "Cymel 301" resin, citric acid and the Dow Corning fluid, were placed in a pebble mill and milled for 20 hours. At the conclusion of this time, the "Cymel 301" resin, citric acid and Dow Corning fluid, were added and milling continued for another 30 minutes. The dispersion was then sprayed onto a polysulfone substrate and baked 10 minutes in a 107° C. oven. The resulting films were tough, scratch resistant and exhibited moderate release properties.
EXAMPLE 4
A coating composition is prepared as follows:
______________________________________"Epon 1007" epoxy resin 15.21%Butyl acetate 33.57%Cellosolve acetate 12.60%n-Butyl acetate 5.31%Methyl isobutyl ketone 3.60%Red iron oxide 1.26%#19 Brown pigment 3.96%Carbon black .45%Calcined alumina 4.41%Portion 1 of Example 1 9.09%Triton X-100 .54%"Cymel 301" resin 7.00%Citric acid 3.00%______________________________________
The ingredients, except for the "Cymel 301" resin and citric acid, were placed in a pebble mill and milled for 20 hours. At the conclusion of this time, the "Cymel 301" resin and citric acid were added to the mill and milling continued for an additional 30 minutes. The dispersion was then sprayed on polyester, polysulfone and polycarbonate substrates and baked for 10 minutes in a 107° C. oven. The resulting films were tough, scratch resistant and exhibited moderate release properties.
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A coating composition comprising a dispersion of an epoxy resin, a nitrogen resin crosslinker such as a melamine formaldehyde, a particulate fluorocarbon such as PTFE, and citric acid can be applied to substrates such as polysulfones and cured at low temperatures on the order of 107° C. The resulting coating is especially useful as a barrier to seal the surface of the substrate and to improve abrasion resistance.
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RELATED APPLICATIONS
This application is a divisional of U.S. application Ser. No. 10/816,261, filed Apr. 1, 2004. Now U.S. Pat. No. 7,111,893 issued on Sep. 26, 2006.
BACKGROUND OF THE INVENTION
This invention relates to vehicle door assemblies and, more particularly, to a vehicle door module with an attachment portion to secure and align an external handle during installation of the door module.
A vehicle door typically includes an outer shell that houses various door components. The door components include a door panel that is received into the outer shell. The door panel operates as an attachment for various door components such as window guides, a safety system, a sound system, and a door locking mechanism. The door panel, attached components, and accompanying system of cables and wires to operate the various components are typically preassembled and then installed into the outer shell as a module.
In particular, the door module includes a handle support that attaches to an external handle through a door shell attachment portion. To attach the external handle to the handle support, the handle support must be aligned with the attachment portion.
Clearance between the width of the door module and the inner width of the door shell is generally small, which may increase the difficulty for an assembler to insert the door module into the door shell and visually align the handle support with the door shell attachment portion. Also, the door module is generally rigid and may be difficult to adjust relative to the attachment portion once the door module is inside the door shell. Presently, insertion of the door module into the door shell, alignment of the handle support with the attachment portion, and attachment of the external handle may be a laborious task.
Accordingly, it is desirable to provide a door module that permits relatively uncomplicated installation and alignment of a handle support.
SUMMARY OF THE INVENTION
The door module according to the present invention includes a latch bracket attached to a door panel. The latch bracket is attached to a door latch which is attached to a handle bracket. The handle bracket includes a hinge portion that flexes during installation of the door module into the door shell. The handle bracket attaches to a handle support that connects to an external door handle through the door shell.
Another door module includes a handle bracket having an annular body portion, a latch attachment portion, and a handle support arm. Arcuate hooks couple the door latch to the handle bracket in a “snap-fit” type of design. A flexible strip allows the handle bracket to flex between positions.
In another door module, a method for aligning the door module with the door shell attachment portion includes flexing a biased hinge portions of the handle bracket to a first position that allows the door module greater clearance with the door shell and facilitates installation of the door module. The greater clearance also allows an assembler to visually align the handle support with the door shell attachment portion.
Another door module includes a handle bracket having a sheathed portion that blocks a seam located on the door latch to prevent debris, water and the like from directly impinging upon the door latch.
In another door module, the handle bracket includes an annular body portion with a latch support attachment portion that engages a latch attachment portion. The annular body portion includes a flexible strip hinge portion that allows the handle bracket to flex between positions. The latch attachment portion of the handle bracket is secured to the door latch and the latch support attachment portion. Arcuate hooks mate with the door latch in a “snap-fit” type of design. A sheathed portion extends from the engagement portion and covers a seam located on the door latch to prevent debris, water and the like from directly impinging upon the door latch.
The door module according to the present invention provides a bracket having a hinge portion that allows uncomplicated alignment of the handle support.
BRIEF DESCRIPTION OF THE DRAWINGS
The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows.
FIG. 1A shows general perspective view of a vehicle having a door and a door module;
FIG. 1B shows a cross sectional view of a door module received in a door shell;
FIG. 2 shows an angled perspective view of a door module;
FIG. 3 shows an angled perspective view of a handle bracket; and
FIG. 4 shows an angled perspective view of another handle bracket.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1A illustrates a vehicle 10 having a door 12 . The door 12 includes a door module 14 . As shown in FIG. 1B , a door shell 18 of the door 12 receives the door module 14 therein with a clearance 16 between the door module 14 and the door shell 18 . The door module 14 is coupled to an external handle 20 through a door shell attachment portion 22 .
Referring to FIG. 2 , the door module 14 includes a door panel 30 that accommodates window guides 32 a and 32 b , each of which define parallel axes 34 along which a window (not shown) moves. A latch bracket 36 is attached to the door panel 30 and extends generally perpendicular to the axis 32 a , 32 b . The latch bracket 36 includes attachment bosses 38 for attachment to the door panel 30 through fasteners or the like. An extended support arm 40 attaches to a door latch 42 . The door latch 42 is attached to a handle bracket 44 with a latch attachment portion 46 that extends generally in the X-Z plane 48 which is generally perpendicular to the door panel 30 . The handle bracket 44 further includes a hinge portion 50 that can pivot from an open to a closed position during installation of the door module 14 into the door shell 18 . A handle support arm 52 of the handle bracket 44 extends generally in the Z-Y plane 54 and attaches to a handle support 56 . The handle support 56 connects to the external handle 20 through the door shell 18 as referred to in FIG. 1B .
The door module 14 also includes a personal identification code (“PIC”) cable 58 that operates an entry keypad (not shown) on the exterior of the door. The PIC cable 58 routes through the handle support 56 , the handle bracket 44 , and the latch bracket 36 to a controller unit 60 in the vehicle 10 . The latch bracket 36 and the handle bracket 44 include a latch bracket cable holder 62 and handle bracket cable holder 64 , respectively, for routing and retaining the PIC cable 58 .
Referring to FIG. 3 , the handle bracket 44 includes an annular body portion 74 defining a Z-Y plane 76 . A latch attachment portion 78 extends generally in the X-Z plane 77 and secures the door latch 42 ( FIG. 2 ) using arcuate hooks 79 . The arcuate hooks 79 preferably mate with the door latch 42 in a “snap-fit” type of design. The handle support arm 52 extends in the Z-Y plane 76 for securing the handle support 56 ( FIG. 2 ).
The annular body portion 74 includes a hinge portion 50 . The hinge portion 50 comprises a flexible strip 80 that allows the handle support arm 52 to flex relative to the door panel 30 . Flexing the hinge portion 50 in a direction 82 achieves a first position 84 .
The hinge portion 50 provides a method for aligning the handle support 56 of the door module 14 with the door shell attachment portion 22 . The method includes flexing the hinge portion 50 to a first position 84 and inserting the door module 14 into the door shell 18 . The first position 84 is relatively closer to the door panel 30 than before flexing. The handle support 56 is aligned with the door shell attachment portion 22 , and the hinge portion 50 is unflexed to an installed position 85 . The installed position 85 is relatively farther from the door panel 30 than the first position. The external handle 20 is attached through the door shell attachment portion 22 . The hinge portion 50 is biased to the installed position 85 . When flexing the hinge portion 50 to the first position 84 , the hinge portion 50 must be held at the first position while inserting the door module 14 into the door shell 18 . When the hinge portion 50 is released from the first position 84 , the bias moves the hinge portion to the installed position 85 . In other examples, the hinge portion 50 has no bias or is biased toward the first position 84 .
The hinge portion 50 provides for alignment of the handle support 44 with the door shell attachment portion 22 . During assembly, flexing the hinge portion 50 to the first position 84 creates increased clearance 16 between the door shell 18 and the door module 14 than if the hinge portion was rigid. The increased clearance facilitates insertion of the door module 14 into the door shell 18 . Also, the greater clearance 16 allows an assembler to visually align the handle support 56 with the door shell attachment portion 22 . The hinge portion 50 has no function once the door module has been installed.
The handle bracket 44 also includes a sheathed portion 86 that extends generally perpendicular from the latch attachment portion 78 . The sheathed portion 86 includes a generally arcuate surface 88 that extends into two planar walls 90 . The planar walls 90 further include a center wall 92 interposed between the planar walls 90 . The center wall 92 preferably blocks a seam located on the door latch 42 (not shown) to prevent debris, water and the like from directly impinging upon the door latch 42 .
Referring to FIG. 4 , the handle bracket 102 includes an annular body portion 104 defining a Z-Y plane 106 , which is approximately parallel to the door panel 30 . A latch support attachment portion 108 extends generally in the X-Z plane 108 and engages a latch attachment portion 110 . The handle support arm 112 extends in the Z-Y plane 106 for securing the handle support 56 ( FIG. 2 ).
The annular body portion 104 includes a hinge portion 114 . The hinge portion 114 comprises a flexible strip 116 that allows the handle support arm 112 to flex relative to the door panel 30 . Flexing the hinge portion 114 in a direction 118 achieves a first position 120 . Unflexing the hinge portion 114 achieves an installed position 121 . The hinge portion 114 is biased to the installed position 121 , although in other examples the hinge portion 50 is biased to the first position or has no bias.
The latch attachment portion 110 of the handle bracket 102 includes an engagement portion 122 for securing to the door latch 42 ( FIG. 2 ). The engagement portion 122 includes an upper engagement portion 124 and a lower engagement portion 126 . The upper engagement portion 124 secures the latch attachment portion 110 to the latch support attachment portion 108 . The lower engagement portion 126 secures the latch attachment portion 110 to the door latch 42 using arcuate hooks 128 . The arcuate hooks 128 preferably mate with the door latch 42 in a “snap-fit” type of design.
The latch attachment portion 110 also includes a sheathed portion 130 that extends generally perpendicular from the engagement portion 122 . The sheathed portion 130 includes a generally arcuate surface 132 that extends into two planar walls 134 . The planar walls 134 further include a center wall 136 interposed between the planar walls 134 . The center wall 136 preferably blocks a seam located on the door latch 42 (not shown) to prevent debris, water and the like from directly impinging upon the door latch 42 .
Although a preferred 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 invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
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A door module includes a bracket having a hinge portion which permits alignment of the handle support of the door module with a door shell attachment portion. The hinge portion of the bracket comprises a flexible strip that allows the bracket to flex between a first and installed position. To install the door module, the hinge portion of the bracket is flexed to the first position such that additional clearance is provided between the door module and the door shell. The door module is located in the door shell and aligned with the door shell attachment portion. The hinge portion is released to the installed position and the handle support is secured to an outside handle.
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FIELD OF INVENTION
[0001] This invention relates to the discovery of autologous stem cells of gastrointestinal origin in fecal matter. More particularly, the invention relates to the isolation and propagation of said stem cells in continuous culture in an unlimited, replicative state in vitro. Furthermore, the invention describes a method of directing and converting these gastrointestinal progenitor stem cells (GIP-C) into immunoglobulin producing cells that secrete autologous antibodies to an antigen.
BACKGROUND OF INVENTION
[0002] The gastrointestinal epithelium undergoes constant and rapid renewal requiring a steady source of proliferating cells to maintain the turnover rate. The deep cryptal layers of the epithelium carry proliferating stem cells that form the source of these cells. These stem cells retain their functional competence over the lifetime of the individual. Tissue based histological studies show that these cells have no loss of cell density and rarely acquire age dependent genetic defects 1 . Until now there has been no evidence to indicate the existence of this progenitor cell population in the exfoliated milieu of cells shed into the fecal stream. Although colonic cells can be recovered in a viable state from stool samples and examined for markers of gastrointestinal (GI) pathology 2 (U.S. Pat. No. 6,335,193), it has not heretofore been known that exfoliated progenitor stem cells of gastrointestinal origin are excreted in fecal matter and that these stem cells can be isolated and maintained in continuous culture in vitro.
SUMMARY OF INVENTION
[0003] It is, therefore, an object of the present invention to isolate and characterize exfoliated progenitor stem cells from fecal matter.
[0004] Another object of the present invention is to provide a method for isolating progenitor stem cells from fecal matter, comprising the steps of:
(i) collecting a sample of fecal matter in SCSR-T medium; (ii) dispersing the fecal sample in the SCSR-T medium; (iii) sedimenting the cells present in the dispersed sample in step (ii) by layering the suspension over a medium of heavier density; (iv) centrifuging the suspension in step (iii) to form a cellular band at the boundary with said heavier medium and combining cells present within said heavier medium and pellet; and (v) culturing the cells obtained from step (iv) to selectively enlarge the population of stem cells present therein.
[0010] It is a further object of the present invention to describe a method for maintaining these stem cells in continuous culture in vitro.
[0011] It is yet another object of the present invention to show that these stem cells express IgA, IgA receptor, secretory component, IgG, IgG receptor, CD20, SSEA-1, SSEA-3, SSEA-4, β-actin, cytokeratin 19 and bind jacalin.
[0012] It is an additional object of the present invention to describe a method for directing and converting these stem cells into immunoglobulin producing cells that secrete autologous antibodies to an antigen.
[0013] It is yet another object of the present invention to produce antibody secreting stem cells generated by allowing the said stem cells to grow on a feeder layer of tumor cells.
[0014] A further object of the present invention is to generate antibody from a lineage of stems cells derived from progenitor stem cells isolated from fecal matter.
[0015] An additional object of the invention is to provide a composition for continuous culture of isolated progenitor stem cells obtained from fecal matter, comprising:
(i) 10%—fetal bovine serum in McCoy's 5A modified medium supplemented with 2 mM L-glutamine; (ii) 2.0-5.0 ml mesenchymal stem cell stimulatory supplement; and (iii) 2.0-5.0 ml mesencult stem cell medium.
[0019] Various other objects and advantages will become evident from the following detailed description of the invention.
BRIEF DESCRIPTION OF DRAWINGS
[0020] The above and various other objects and advantages of the present invention will be better understood by reference to the accompanying drawings which are only illustrative and not limiting of the embodiments of the invention.
[0021] FIG. 1 shows phase contrast photomicrograph of GIP-C cells.
DETAILED DESCRIPTION OF INVENTION
[0022] The present invention is related to the characterization of exfoliated progenitor cells isolated from fecal matter, and to methods relating to their maintenance in continuous culture.
[0023] It should be noted that these exfoliated progenitor cells isolated from fecal matter are designated as “stem cells”, which term herein means that they are self-maintaining, have extensive self-renewing proliferative capacity and can be directed or converted to a differentiated derivative. Characterization of the isolated stem cells of the present invention is accomplished by well-established standard methodology including detection of certain cell surface markers through flow cytometry, nuclear staining techniques using propidium iodide, by the expression of epithelial lineage marker cytokeratin-19, or by the housekeeping gene β-actin through RT-PCR, and the like 3-6 .
[0024] The growth and maintenance of these stem cells in continuous culture is accomplished in a unique defined medium, both in the presence and absence of antibiotics, and by coating of plates with various epithelial attachment factors.
[0025] A subset of cells that has been differentially converted into a lineage of immunoglobulin secreting cells has also been accomplished.
[0026] It was discovered that these stem cells express at least the following cell surface markers: IgA, IgG, IgAR, IgGR, secretory component, CD8, CD20, SSEA1 (Stage Specific Embryonic Antigen 1), SSEA3, SSEA4, IgA+IgG, IgA+SC, IgA+SSEA1, and IgA+SSEA 37-11 . By combining nuclear staining with cell surface marker methodology, it was found that there are at least two different lineage-committed populations of cells. It was further established by isolating mRNA and expressing cytokeratin-19 and β-actin through RT-PCR that these cells are intact and that there is a subpopulation committed to epithelial lineage.
[0027] The progenitor cells of the present invention grown in culture are mostly in suspension and when these cells were tested with five epithelial cell attachment factors, viz., collagen type IV, fibronectin, superfibronectin, ECM gel and laminin, it was discovered that a certain population of the these cells does attach itself to all the attachment matrices.
[0028] It should be understood that unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the methods and materials described herein are preferred. Unless mentioned otherwise, the techniques employed or contemplated herein are standard methodologies well known to one of ordinary skill in the art. The materials, methods and examples are only exemplary and not limiting.
Methods and Materials
[0000] Isolation of Cells Containing GIP-C from Stool Samples.
[0029] Optimal mass of a fecal sample (generally about 0.5-1.0 gram) was collected at normal ambient temperature in a preweighed collection tube containing 15 ml of SCSR-T media (Noninvasive Technologies, 8170 Lark Brown Road, Suite 101, Elkridge. Md. 21075)) and glass beads. The sample was vortexed thoroughly and poured into a 7″×12″ doublesided filter bag (Tekmar-Dohrmann, Cat no. 10-0838-00). The sample was filtered through 40 μm nylon filter (BD-352340). The resuspended filtered sample from about 0.5 g of original fecal matter was removed and the volume was adjusted to 25 ml with SCSR-T media (Noninvasive Technologies). Ten ml of cushion solution, SCSR-C (NonInvasive Technologies) was used to underlay the sample without disturbing the top layer. The samples were spun for 10 minutes at 200 g. After discarding the supernatant the interface was carefully removed into a prelabelled 50 ml tube. The pellet and cushion above the pellet were placed in separate 50 ml tubes. The volume of the Pellet and Interface was adjusted to 15 ml by adding 1×PBS pH 7.2 and the samples were resuspended by inverting the tubes several times. The supernatant was carefully decanted after spinning the samples at about 2000 rpm, for about 10 minutes at about 4° C. (IEC Centra-8R Centrifuge). Another 15 ml of 1×PBS was added to the tubes and the cells were spun again at the conditions mentioned previously. The pellet was resuspended in 1 ml of 1×PBS (a cell count was obtained using a Z2 Beckman Coulter) and 250 μl aliquots of the sample was transferred into four 1.5 ml tubes. The cells were spun at about 1500 rpm, for about 10 minutes at about 4° C. The supernatant was aspirated and the pellets were resuspended in 50 μl of serum free cell freezing medium (Sigma C2639), and stored at −70° C. for archival purposes if they were not used for cell culture.
[0000] Culture Conditions and Methodology
[0030] Cells were isolated from about 0.5 g of stool as described in the procedure above, and the final pellets were resuspended in 1 ml of 1×PBS pH 7.2 and counted using a Z2 Beckman Coulter counter Two ml of Methocult SF (04436) and Mesencult (05401) stem cell media, purchased from Stemcell Technologies Inc, was added to four wells of a six well plate. An aliquot containing the number of cells desired from pellet and interface was added to each plate. The cells were maintained in a CO 2 incubator (5% CO 2 ) at about 37° C. for a week before the cells were subcultured, while observations were made everyday. To subculture the cells, 2 ml of sterile 1×PBS pH 7.4 was added to one of the two wells for pellet and interface. The wells were scraped and the contents were pippetted into 15 ml conical tubes. Another 5 ml of 1×PBS pH about 7.4 was added to the well to rinse, and the contents were added to 15 ml tube. The samples were spun at about 1500 rpm, for about 10 minutes at about 4° C. (IEC Centra-8R Centrifuge). After the supernatant was aspirated, the pellets were resuspended in 2 ml 1×PBS pH about 7.4. Then about 0.5 ml of the resuspended cells were added to each well containing the appropriate stem cell medium.
[0000] Methocult SF Composition:
[0031] 1%—Methylcellulose in Iscove's MDM
[0032] 1%—Bovine Serum Albumin
[0033] 10 μg/ml—Bovine Pancreatic Insulin
[0034] 200 μg/ml Human transferrin (Iron-saturated)
[0035] 3 U/ml—rh Erythropoietin
[0036] 10 μl 2-Mercaptoethanol
[0037] 2 mM—L-glutamine
[0038] 50 ng/ml—rh Stem cell factor
[0039] 20 ng/ml—rh GM-CSF
[0040] 20 ng/ml—rh IL-3
[0041] 20 ng/ml—rh IL-6
[0042] 20 ng/ml—rh G-CSF
[0000] Mesencult Media Composition:
[0043] Fetal bovine serum (10%) in McCoy's 5A Medium (modified) supplemented with L-glutamine (2 mM). Mesenchymal stem cell stimulatory supplements (human) (Stemcell Technologies Cat No. 05402) was added to the Mesencult media.
[0000] Flow Cytometry
[0044] Flow cytometric studies were conducted for two main categories, namely surface antigen staining and nuclear staining. The surface antigen staining studies were further divided into three categories: direct staining, indirect staining and two color staining.
[0000] Surface Antigen Staining
[0000] Direct Staining Studies:
[0045] The following markers were tested using direct staining studies with antibodies at the appropriate dilution on the subcultured GIP-C cells derived from two separate sources grown in methocult and mesencult stemcell media. (a) The presence of IgA was tested using two different methods: (i) goat anti human 19A FITC (o chain specific) (Sigma, F2879) and (ii) Jacalin FITC from Artocarpus integrfolia (EY Laboratories, F6301-2). (b) Secretory component: FITC conjugated IgG fraction of goat polyclonal antiserum to human secretory component, free and bound (Nordic Immunology, 3913). (c) IgG: anti human IgG (y chain specific) PE conjugate developed in goat (Sigma, P8047). (d) FCR/IgG Receptor (IgGR): human IgG FITC (Sigma, F9636). (e) CD8: mouse monoclonal anti CD8 clone UCHTA FITC conjugate (Sigma, F0772). (f) CD4: mouse monoclonal anti CD4 clone Q4120 FITC conjugate (Sigma, F1773). (g) CD19: mouse monoclonal antibody, clone 4G7 FITC conjugate (Becton Dickinson, 347543). (h) CD34: monoclonal antibody from mouse (Anti-HPCA-2) clone 8G12 FITC conjugate (Becton Dickinson, 348053). (i) CD45: monoclonal antibody from mouse, clone 2D1 FITC conjugate (Becton Dickinson, 347463). (j) CD45RA: monoclonal anti-human CD45RA FITC conjugate, clone F8-11-13 (Sigma, F1527). (k) CD54: monoclonal antibody from mouse, clone LB-2 PE conjugate (Becton Dickinson, 347977). (l) CD117: monoclonal antibody from mouse, clone 104D2, PE conjugate (Becton Dickinson, 340529).
[0046] The subcultured GIP-C cells from the two samples, A and B, that were stored in freezing media, at −70° C., were washed in 1 ml of 1×PBS 1% BSA. The cells were spun down at 1500 RPM for five minutes (IEC Centra -8R Centrifuge), aspirated and resuspended in 0.5 or 1 ml of PBS 1% BSA depending on the cell counts. Flow Cytometric studies were conducted with 100,000-200,000 cells which were aliquoted into 5 ml polystyrene round bottom tubes (BD Falcon, 352054) and the volume was adjusted to 100 μl with 1×PBS 1% BSA. Between 10 μl-20 μl of antibody, diluted in PBS containing 1% BSA was added to each sample. The samples were then incubated for an hour at 37° C. while gently mixing. They were then washed twice by adding 2 ml of cold 1×PBS 1% BSA per tube and mixed against the side of the rack, and spun at 2000 RPM for five minutes at 4° C. (IEC Centra-8R Centrifuge), and the supernatant was removed. The cells were then resuspended in 1 ml of 5% paraformaldehyde. The samples were stored at 4° C. until analyzed.
[0000] Indirect Staining Studies:
[0047] The following markers were used for indirect staining studies with subcultured GIP-C cells (A and B) using antibodies with appropriate dilutions. The antibodies for the markers tested were added in the following order: (a) IgA Receptor (IgAR): monoclonal anti human IgA (α chain specific), clone GA-112 (Sigma, 10636)+Human IgA pure from human colostrum (Sigma, 11010)+goat anti human IgA FITC. (b) CD20: monoclonal anti human CD20 purified mouse immunoglobulin (Sigma, C8080)+anti mouse IgG (whole molecule) FITC conjugate developed in rabbit (Sigma, F9137). (c) SSEA1: mouse anti SSEA1 monoclonal antibody clone MC480, immunogen: F9 teratocarcinoma stemcells (X-irradiated), (MAB4301 Chemicon)+anti mouse IgG FITC conjugate. (d) SSEA3: mouse anti SSEA3 monoclonal antibody, clone MC 631, immunogen: 4-8 cell stage mouse embryos, (MAB4303 Chemicon)+anti mouse IgG FITC conjugate. (e) SSEA4: mouse anti SSEA4 monoclonal antibody clone MC-813-70, immunogen: human embryonal carcinoma cell line 210Ep, (MAB4304 Chemicon)+anti mouse IgG FITC conjugate.
[0048] The procedure of indirect staining was similar to that of direct staining, the only difference being the length of the incubation period, which was 30 minutes at 37° C. for each antibody that was added to the cells.
[0000] Two Color Staining Studies:
[0049] The following markers were used for two color staining studies with subcultured GIP-C cells initially from both A and B methocult and mesencult samples, but later only from B mesencult pellet and interface cells from passages 38 and 40. The antibodies for the markers tested were added in the following order: (Note: the first two markers were initially tested with A and B samples, added during separate incubations at 37° C. for 30 minutes) (a) IgA (FITC)+SC (PE): goat anti human IgA FITC+mouse monoclonal anti-human SC (Sigma, 16635)+Rabbit anti mouse IgG (whole molecule) PE (Sigma, P 0313 ). (b) IgA (jacalin FITC)+SC (PE): jacalin FITC ( Artocarpus integrifolia )+mouse monoclonal anti-human SC+Rabbit anti mouse IgG (whole molecule) PE. (c) IgA FITC+SSEA1 PE: goat anti human IgA FITC (α chain specific)+mouse anti SSEA1 monoclonal antibody clone MC480+Rabbit anti mouse IgG (whole molecule) PE. (d) IgG (PE)+SSEA1 (FITC): anti human IgG (y chain specific) PE conjugate+mouse anti SSEA1 monoclonal antibody clone MC480+anti mouse IgG (whole molecule) FITC. (e) IgA (FITC)+IgG (PE): goat anti human IgA FITC+anti human IgG PE. (f) IgG (PE)+IgA (FITC): anti human IgG PE+goat anti human IgA FITC. (g) fgA (FITC)+SSEA3 (PE): goat anti human IgA FITC+rat anti SSEA3 monoclonal antibody, clone MC 631+rabbit anti mouse IgG (whole molecule) PE. (h) IgG (PE)+SSEA3 (FITC): anti human IgG PE+rat anti SSEA3 monoclonal antibody, clone MC 631+anti mouse IgG FITC. (i) IgA (FITC)+SSEA4 (PE): goat anti human IgA FITC+mouse anti SSEA4 monoclonal antibody clone MC-813-70+rabbit anti mouse IgG (whole molecule) PE. (j) IgG (PE)+SSEA4 (FITC): anti human IgG PE+mouse anti SSEA4 monoclonal antibody clone MC-813-70+anti mouse IgG (whole molecule) FITC. (k) IgA (FITC)+CD20 (PE): goat anti human IgA+monoclonal anti human CD20+rabbit anti mouse IgG (whole molecule) PE. The antibodies were added in the given order and incubated separately at 37° C. for 30 minutes.
[0050] Some of the markers tested above were added together and incubated overnight at 4° C. as well. They were as follows: (a) IgA (FITC)+IgG (PE); (b) IgA (FITC)+CD20 (PE); (c) IgA (FITC)+SSEA3 (PE). The markers that needed the addition of a secondary antibody carrying a FITC or PE label were added after the first wash, after the overnight incubation, and then incubated for a half hour at 37° C.
[0000] Nuclear Staining Studies
[0051] The nuclear staining studies were done initially by adding propidium iodide staining solution to the subcultured GIP-C cells and later to subcultured GIP-C cells that were initially stained with fluorescently-labelled antibodies. The procedures for both the studies were as follows:
[0000] Preliminary Studies Using Propidium Iodide with Subcultured GIP-C Cells
[0052] Propidium iodide (BD Biosciences) was dissolved in PBS (pH 7.4) at the concentration of 50 μg/ml. Two tubes of one million GIP-C cells from five different subcultured samples were used. The samples were as follows.
[0053] Five different subcultured samples were chosen for this study: C: methocult pellet, A: methocult interface, B: methocult pellet, E: mesencult pellet and D: methocult interface. The cells were scraped and washed with PBS pH 7.4 and a cell count was obtained. The cells were spun down and then resuspended in PBS+1% BSA. Two tubes of one million GIP-C cells were obtained from each sample. Propidium iodide (50 μl of 50 μg/ml) was added to one tube of each sample to a 0.7 ml cell suspension the total volume being 950 μl. NP40 (200 μl, 0.5% in PBS 7.2) was added to the other set of tubes of GIP-C cells and they were put on ice for 15 minutes. Propidium iodide (50 μl of 50 μg/ml) was added to the cells in NP40. Both sets of cell were run on the flow cytometer after vortexing the samples.
[0000] Propidium Iodide with Stained Subcultured GIP-C Cells
[0054] Another set of propidium iodide studies were done with stained GIP-C cells. Propidium iodide (10 μl of 50 μg/ml) was added to GIP-C cells stained with the following markers: (a) IgG (PE)+IgA (FITC), (b) IgA (FITC), (c) IgA (FITC)+SSEA1 (PE), (d) IgG (PE)+SSEA1 (FITC), (f IgA (FITC)+SSEA3 (PE), (g) IgG PE+SSEA3 (FITC), (h) IgA (FITC)+SSEA4 (PE), (i) IgG (PE)+SSEA4 (FITC), (i) IgA (FITC)+CD20 (PE), (j) IgA (FITC)+IgG (PE). The antibodies for the above mentioned markers were added and incubated individually at 37° C. for a half hour period.
[0055] A third set of propidium iodide studies were done where the primary antibodies for two color markers were added together and incubated at 4° C. overnight initially and after a wash the secondary antibody was added and incubated at 37° C. for a half hour before being fixed. Propidium iodide (10 μl of 50 μg/ml) was added to the following markers: (a) IgA (FITC)+IgG (PE), (b) IgA (FITC)+CD20 (PE) and (c) IgA (FITC)+SSEA3 (PE).
[0000] Isolation of mRNA from Subcultured GIP-C Cells.
[0056] mRNA from subcultured GIP-C cells were isolated using the procedure described by Nair et al 2 . Also a PCR was run testing the presence of O-actin (housekeeping gene), and cytokeratin 19 (marker for epithelial lineage) primers. The sequences of the primers used were as follows:
β-actin 5′ TCACCAACTGGGACGACATG β-actin 3′ ATGTCACGCACGATTTCCCG Keratin19 5′ ATCCTGAGTGACATGCGAAGC Keratin19 3′ CATGAGCCGCTGGTACTCCTG
Antibiotic Studies with Subcultured GIP-C Cells
[0057] A 100× antibiotic/antimycotic mixture was obtained from Sigma (A5955). Six different concentrations of antibiotic/antimycotic were used in mesencult media. The concentrations used were as follows: 0×, 115×, 215×, 315×, 415× and 1×. Half a million cells of specimen A mesencult pellet and interface cells were added to 1.5 ml of different concentrations of antibioticimycotic mixture in mesencult media. The cells were incubated at 37° C. for a week, and were observed daily. Initially triplets were made of the same concentrations, but a week later the triplets of each concentrations were combined and subcultured and resuspended in mesencult media containing the appropriate concentrations of antibiotic/mycotic mixture. Cell counts were obtained from all of the subcultured samples. In order to observe the cells under the hemocytometer, the subcultured GIP-C cells which were exposed to the antibiotic/mycotic mixture had to be washed initially. The procedure is as follows: 0.5 ml of GIP-C cells were obtained from Ox and 1× samples. A solution containing 50 mg of NCL006 (Noninvasive Technologies) in 5 ml of mesencult media was made. One ml of the mixture was added to 0.5 ml of the GIP-C cells and mixed. After waiting for 5 minutes the cells were spun for 5 minutes at 2000 RPM at 4° C. (IEC Centra -8R Centrifuge). This step was repeated once again. The pellet was resuspended in 0.5 ml of mesencult media, and added to another 0.5 ml of media with the appropriate concentration of antibiotic/mycotic mixture. A small aliquot of cells were taken and observed under the hemocytometer, while the rest of the GIP-C cells were incubated at 37° C. in the antibiotic/mycotic media.
[0000] Study of Attachment Factors with Subcultured GIP-C Cells
[0000] Coating the Wells with Attachment Factors:
[0058] Two of the six well plates were coated with the following attachment factors: Collagen type IV, Fibronectin, Superfibronectin, ECM gel and Laminin. Collagen type IV (2 mg/ml) was made by dissolving 0.75 mg of collagen in 375 μl of sterilized 0.25% acetic acid. Collagen type IV (187.5 μl) was used to coat two wells and incubated overnight at 2-8° C. Fibronectin (250 μl of 10 μg/ml) was used to coat each well and air-dried at room temperature for 45 minutes. Superfibronectin (250 μl of 5 μg/ml) was used to coat each well and incubated at 37° C. for two hours. The wells were then washed twice with 100 μl of PBS, and left to air dry in a laminar flow hood. ECM gel was thawed overnight before use; 250 μl of ECM gel was mixed with 250 μl of cold DMEM medium before using 250 μl of the mixture to coat precooled wells. The ECM gel was then left for five minutes at 20° C. for the gel to polymerize. An aliquot of 200 μg/200 μl of laminin was thawed at 4° C. for 2-4 hrs before making a dilution using 36 μl of stock solution and diluting it with 464 μl of sterile PBS. Laminin (250 μl, 18 μg/well) was used to coat each well. The plates with laminin were then air-dried for 45 minutes. All of the plates containing the attachment factors were sterilized overnight by exposure to UV light in a sterile tissue culture hood.
[0000] Preparing the RPMI 1640 Media for Attachment Factor Study:
[0059] RPMI 1640 media (250 ml) was obtained from Invitrogen (11875-085), to which the following supplements were added: 100 ng/ml of cholera-toxin (Sigma, C8052), 500 ng/ml of hydrocortisone (Sigma, H0888), 5% of heat inactivated horse serum (Gibco, 16050-130) and 25 ml of Mesenchymal supplement (Stemcell technologies, 05402). After the media was filter sterilized and aliquots of 26 ml were made, they were stored at 4° C.
[0060] RPMI 1640 media with all the supplements was warmed at 37° C. Two ml of the media was added to each well containing the attachment factors along with 3 control wells which contained no attachment factors. Cells previously subcultured in mesencult medium were pelleted and divided into 100,000 cells per well and incubated at 37° C. The cells were observed under a phase-contrast microscope. Once, every two days the top layer containing the unattached GIP-C cells was removed, washed and resuspended in freezing media. Two ml of RPMI 1640 media with the supplements was added to the wells and incubated at 37° C.
Results
[0061] A number of markers were tested on the subcultured progenitor cells using flow cytometry. The following table displays the statistics on the percentage of progenitor cells expressing the markers tested:
TABLE 1 Markers Passage No. N Mean SEM IgA FITC 12 & 16 16 3.3 SC FITC 12, 13, 15, & 16 32 2.6 IgG PE 13 & 15 16 2.3 IgAR FITC 13 8 5.0 FcR/IgGR FITC 13 8 5.4 CD 8 FITC 18 8 0.2 CD 20 FITC 22, 23, 40 18 3.0 SSEA1 FITC 22, 23, 38 & 40 20 2.5 SSEA3 FITC 22, 23, 38 & 40 20 2.7 SSEA4 FITC 22, 23 & 38 18 2.7 * SC (PE) + IgA (FITC) 12 & 16 16 LR quadrant IgA FITC 30.1 2.2 UL quadrant SC PE 1.0 0.4 UR quadrant IgA + SC 2.0 ** IgA (FITC) + SC (PE) 13 & 16 16 LR quadrant IgA FITC 11.4 2.6 UL quadrant SC PE 3.4 0.8 UR quadrant IgA + SC 0.8 IgA Jacalin (FITC) 15 8 3.1 * SC (PE) + IgA Jacalin (FITC) 15 & 16 16 LR quadrant IgA jac FITC 14.3 2.1 UL quadrant SC PE 0.7 0.3 UR quadrant IgA + SC 4.3 ** IgA Jacalin (FITC) + SC (PE) 15 & 16 16 LR quadrant IgA jac FITC 6.6 2.1 UL quadrant SC PE 2.3 0.6 UR quadrant IgA + SC 4.2 IgA (FITC) + IgG (PE) 38 & 40 4 LR quadrant IgA FITC 22.5 1.7 UL quadrant IgG PE 6.2 0.5 UR quadrant IgA + IgG 3.0 IgA (FITC) + CD20 (PE) 40 4 LR quadrant IgA FITC 2.8 1.8 UL quadrant CD20 PE 1.5 0.3 UR quadrant IgA + CD20 1.8 IgA (FITC) + SSEA1 (PE) 38 & 40 4 LR quadrant IgA FITC 8.2 1.6 UL quadrant SSEA1 PE 1.2 0.4 UR quadrant IgA + SSEA1 2.1 IgA (FITC) + SSEA3 (PE) 38 2 LR quadrant IgA FITC 7.5 6.0 UL quadrant SSEA3 PE 1.1 0.7 UR quadrant IgA + SSEA3 1.3 IgA (FITC) + SSEA4 (PE) 38 2 LR quadrant IgA FITC 0.4 1.1 UL quadrant SSEA4 PE 3.8 1.6 UR quadrant IgA + SSEA4 0.3 IgG (PE) + SSEA1 (FITC) 38 2 LR quadrant SSEA1 FITC 23.1 3.0 UL quadrant IgG PE 0.1 0.0 UR quadrant IgG + SSEA1 9.6 IgG (PE) + SSEA3 (FITC) 38 2 LR quadrant SSEA3 FITC 32.7 5.2 UL quadrant IgG PE 0.5 0.0 UR quandrant IgG + SSEA3 2.6 * The order of the antibodies added was SC (PE) and IgA (FITC). ** The order of the antibodies added was IgA (FITC) and SC (PE). SEM: Standard Error of Mean N: Number of replicates
[0062] Flow cytometric studies with progenitor cells were negative for the expression of the following markers: CD19, CD34, CD45, CD45RA, CD54 and CD117. There was a small population of cells containing CD8 (1.3%), a T-cell marker, and about 38.5% of cells containing CD20, a B-cell marker. Coexpession studies of IgA+SC (secretory component) were performed using anti IgA antibody as well as jacalin FITC (which recognizes IgA). Without being bound to any theory, it is hypothesized that the antibody against IgA initiated a biological activity in cells which led to masking or endocytosis or even reorientation of IgA in the membrane which produced low detection levels of free IgA (this phenomenon was also detected with other combination studies discussed below). While for non-antibody marker (Jacalin FITC) such biological activity was not elicited, these studies along with backgating exercises and histogram analysis showed that most of the progenitor cells coexpressed IgA+SC on the same cell. The existence of cells containing only IgA as well as secretory component was also observed. Two-color flow cytometric studies to elicit coexpression of IgA+IgG showed the presence of four different populations of cells: cells with IgA, cells with IgG, cells with IgA+IgG, and cells containing neither IgA nor IgG. Similar two-color studies of IgA and IgG with different Stage Specific Embryonic Antigens indicated that there might be lineage-directed changes in which some stem cells are transformed into immunoglobulin secreting cells while others continue dividing thereby maintaining a pool of progenitor cells available for lineage directed differentiation under appropriate conditions. When IgA was combined with CD20, the CD20 appeared to hinder the IgA binding to the cells, indicating an interaction that results in release of IgA+CD20 into supernatant.
[0063] Propidium iodide studies demonstrated that all the cells were nucleated, but not all nucleated cells necessarily carried the cell surface markers which were tested. When flow cytometry studies were combined with nuclear staining studies containing propidium iodide an upward shift in the population from the unstained region was observed. This was parallel to the shift seen in the LR quadrant events. When propidium iodide was added to cells stained with the three Stage Specific Embryonic Antigens (1, 3 and 4), about 5% of cells were nucleated and carried the marker for SSEAL and 4, whereas, for SSEA3, 20% of the cells were nucleated and carried the marker. This suggested that there might be two populations for Stage Specific Embryonic Antigens in existence, one of which (SSEA3) was older than SSEA1 and SSEA4. This could indicate the existence of more nucleated cells in the SSEA3 population. For the next set of combination studies with IgA or IgG with SSEAs, a similar shift was observed when propidium iodide was added. This appearance of two distinct populations of cells indicated that there existed cells with different amounts of DNA. This phenomenon was also seen with IgA+CD20 when propidium iodide was added.
[0000] Expression of β-Actin and Cytokeratin 19 by the Subcultured GIP-C Cells
[0064] mRNA was isolated from subcultured progenitor cells and then RT-PCR was performed to see if the cells expressed β-actin and cytokeratin 19.
[0065] The subcultured cells expressed both β-actin and cytokeratin 19 proving that these cells were eukaryotic, some of which were of epithelial lineage.
[0000] Antibiotic/Antimycotic Studies with Subcultured GIP-C Cells.
[0066] It is a generally recognized fact that cells lining the large bowel (colon) are in constant contact with a large microbial population and are adapted to this environment. In a similar manner GIP-C cells also had high levels of bacteria associated with them, a condition that persisted even when the GIP-C cells were being grown in continuous culture. To observe the effect of antibiotics on the growth of these progenitor GIP-C cells, they were grown in culture with varying concentrations of antibiotic/antimycotic mixture. The cell counts taken at different times were as follows:
TABLE 2 2nd subculture after washing 1st subculture w/NCL006 Antibiotic Initial Counts 2-5 μm 2-5 μm concentrations (Cells/ml) (Cells/ml) (Cells/ml) 0× 8.60E+06 1.54E+07 1.00E+07 1/5× 8.11E+06 2.98E+06 2/5× 5.13E+06 3.98E+06 3/5× 1.23E+06 2.26E+06 4/5× 3.57E+06 1.21E+06 1× 5.17E+06 2.18E+06
[0067] There was no consistent trend indicating a drop in the cell counts with increasing concentrations of antibiotic/antimycotic mixture. NCL006 (NonInvasive Technologies), 0.5% in PBS was used to wash the cells and clear the mucous before viewing the cells under a phase contrast microscope. Although the number of GIP-C cells had decreased considerably after each subculture, they still seemed to be growing and dividing in the presence of antibiotic/antimycotic mixture. There were some remnants of bacteria left in the higher antibiotic concentrations, but the media was mostly clear. At higher concentrations of antibiotic/antimycotic mixture GIP-C cells appeared to be larger in size. Cell counts were taken of GIP-C cells in sizes ranging from 1-3 μm, 2-5 μm, and 5-8 μm from the second subculture after washing with NCL006. The counts were as follows:
TABLE 3 Cell counts from 2nd subculture after washing w/NCL006 Antibiotic 1-3 μm 2-5 μm 5-8 μm concentrations (Cells/ml) (Cells/ml) (Cells/ml) 0× 6.23E+06 1.00E+07 972634 1/5× 3.35E+08 2.98E+06 235170 2/5× 796683 3.98E+06 212256 3/5× 1.79E+08 2.26E+06 299088 4/5× 2.60E+08 1.21E+06 185322 1× 3.49E+06 2.18E+06 171252
[0068] The cell count seems to decrease as the size range increases from 1-3 μm to 2-5 μm to 5-8 μm.
[0000] Attachment Factors Study
[0069] The gastrointestinal progenitor cells in culture were found mostly in suspension in the culture media. In order to test the adherence of these cells a study was conducted where they were plated on tissue culture wells coated with each of the five different epithelial cell attachment factors: collagen type IV, laminin, superfibronectin, fibronectin, and ECM gel. There were three control wells with no attachment factors in them. The cell counts obtained were as follows:
TABLE 4 Cell counts in Cell counts of Supernatant Attached cells (Cells/ml) (Cells/ml) Attachment factors 2-5 μm 5-8 μm 2-5 μm 5-8 μm Control 1 4.94E+07 162810 Control 2 1.51E+07 141504 Control 3 2.92E+07 143916 Collagen type IV (well 1) 1.60E+07 149544 1.19E+06 NA Collagen type IV (well 2) 1.22E+07 65526 2.25E+06 57486 Laminin (well 1) 4.09E+07 90048 974448 40602 Laminin (well 2) 3.04E+07 84822 643602 43416 Superfibronectin (well 1) 3.96E+07 67536 1.62E+06 14874 Superfibronectin (well 2) 5.06E+07 54672 1.35E+06 52260 Fibronectin (well 1) 2.99E+07 68340 NA 52260 Fibronectin (well 2) 1.04E+06 63918 68340 20502 ECM gel (well 1) 2.94E+07 245220 1.32E+06 24924 ECM gel (well 2) 1.28E+07 54672 764604 53064
[0070] Even though most attachment factors seem to attach the cells, certain attachment factors such as collagen type IV, superfibronectin and ECM gel seemed to be better at attaching cells from 2-5 μm. As seen from the above data, there were also some cells of 5-8 μm that were attached to the five different attachment factors. It seemed that a certain population of cells was attached and others were in suspension, and the degree of attachment varied with the different attachment factors used.
[0000] Culturing GIP-C Cells on Feeder Layer of Mitomycin C Treated HT-29 Cells for Inducing Immunoglobulin Producing Lineage
[0071] Preparation of Feeder Layer:
1. Grow HT-29 cells in McCoy 5A medium containing 10% FBS to confluency 2. Remove medium and wash cells with PBS −2 times 3. Add 15 ml of 10 ng/ml Mitomycin C stock solution to each flask and swirl to cover surface 4. Incubate at 37° C. for 3 hours 5. After incubation, aspirate off the Mitomycin C and wash 3 times with 20 ml of PBS 6. Add trypsin EDTA to remove the cells and add McCoy 5A medium containing 10% Fetal bovine serum to stop the trypsin action 7. Wash the cells three times with 20 ml of PBS at 2000 rpm for 10 min. 8. Check the cell count and suspend the cells in medium adjusting the density to about 3.5×10 5 cells/ml and put them in a tissue culture flask as follows: (Note: Cells should not be frozen after Mitomycin C treatment.)
Culture of GIP-C Cells on Feeder Layer:
1. Seed the Mitomycin C treated cells (at about 3.5×10 5 cells/ml) in T-75 flask 2. Allow the cells to attach for at least 2 hrs or preferably overnight 3. Take frozen GIP-C cells at −70° C., which have already been grown in mesencult medium from interface and pellet fractions 4. Wash the GIP-C in cold PBS at 2000 rpm for 10 min 5. Seed these cultured GIP-C cells in 2 flasks/in RPMI-1640 medium containing 5% horse serum (HS) (heat-inactivated and preadsorbed IgG) from each fraction of interface and pellet. Also, take 2 flasks of mitomycin C treated HT-29 cells with complete RPM I 1640 medium alone as control. 6. Grow the cells for one week at 37° C. in 5% CO 2 without changing or adding the medium. Mitomycin C stock: (It is toxic, wear gloves and use caution when handling) Prepare 1 mg/ml of PBS, store the solution in dark by covering the tube with aluminum foil and use within 2 weeks. Diluted Stock #1 (10 μg/ml): Take 20 μl of stock (1 mg/ml), and add 2 ml of medium.
[0089] Diluted Stock #2 (10 ng/ml): Take 100 μl of diluted stock #1, and add 100 ml of medium.
TABLE 5 Modified RPMI-1640 medium used for transit of GIP-C cells into IgG secreting lineage Final Stock solution conc. 10 ml 50 ml. 100 ml 250 ml 1 RPMI-1640 83% 7.8 ml 39 ml 78 ml 195 ml medium 2 Glutamax 2 mM 100 μl 500 μl 1 ml 2.5 ml (200 mM) 3 Horse serum or 5% 1 ml 5 ml 10 ml 25 ml Human AB serum (50%, Heat in- activated and preadsorbed on Protein A agarose) 4 Mesenchymal 10% 1 ml 5 ml 10 ml 25 ml supplement 5 Hydrocortisone 500 100 μl 500 μl 1 ml 2.5 ml. (50 μg/ml) ng/ml
Stock Solutions:
[0090] 1. Glutamax (200 mM): Aliquot 2.5 ml/vial and freeze at −20° C.
[0091] 2. Horse serum:
i) Heat Inactivation: Heat inactivate the HS by incubating at 56° C. for 30 min. Make aliquots of 12.5 ml in 15 ml sterile tubes. ii) Removal of IgG:
a) Dilute HS to 50% by mixing 1 volume of HS with 1 volume of RPMI-1640 medium. b) Adsorb 3 volumes of 50% HS with 1 volume of protein A agarose packed beads. c) Stir at 4° C. overnight. d) Centrifuge at 4500 rpm for 10 min. Remove the supernatant and use it as preadsorbed HS. e) Regenerate protein A agarose according to the protocol.
[0099] 1. Hydrocortisone (50 μg/ml):
i) Add 5 ml of absolute ethanol to 5 mg of product, gently swirl to dissolve. ii) Prepare 25 aliquots of 200 μl each and store at −20° C.
[0102] iii) Just before use, take 100 μl of stock solution and add 1.9 ml of RPMI 1640 medium.
TABLE 6 Amount of IgG eluted from GIP-C grown on feeder layer of Mitomycin C treated HT-29 cells Type of IgG eluted (mg/ml of culture supernatant) Medium Mitomycin C treated HT-29 cells + GIP-C Medium 1 0.37 Medium 2 0.33 Medium 3 0.28 Medium 4 0.01 Medium 5 0.57 Medium 1: Modified RPMI 1640 medium without hydrocortisone Medium 2: Modified RPMI 1640 medium without Mesencult supplement Medium 3: Modified RPMI 1640 medium without hydrocortisone and Mesencult Medium 4. Complete Modified RPMI medium with human AB serum Medium 5: Complete Modified RPMI 1640 medium with horse serum
Isolation of IgG from Culture Medium of GIP-C
2. Hydrate 1 g of Protein A agarose (cat.# P-0932) in about 20 ml of phosphate buffer A. It should swell to about 4 ml packed volume, wash 2 times with 20 ml of phosphate buffer. 3. Resuspend 4 ml of beads in 4 ml of Buffer A (double the packed volume) 4. To each of 4 tubes containing filtered culture supernatant, add 1 ml of bead suspension from above (500 μl of packed volume or about 8 equal parts) to each tube, mix the beads well with the culture supernatant. Leave 8 tubes on the rocker platform for 2 hrs at room temp. Make sure that beads mix well with the culture supernatant well. 5. Centrifuge samples at 5000 rpm for 5 min at room temp. 6. Remove supernatant, combine supernatants from all 3 tubes of test interface, 3 tubes of test pellet and 2 tubes of control separately, save it as Wash #1 Interface, and Wash #1 pellet. Wash the beads with 10 ml of Buffer A by repeating step # 4 twice, Save the wash both times, separately as Wash #2 and Wash #3 7. Read absorbance at 280 nm for all 3 washes, absorbance in Wash #3 must be zero 8. Suspend the beads in about 1 ml of buffer A each, and pool them in one tube. 9. Remove supernatant and suspend the beads in 750 μl buffer B, pH 4.0 per tube, leave the tubes at RT for 15 min, mixing tubes 2-3 times during elution 10. Centrifuge at 5000 rpm for 5 min at RT 11. Remove the supernatant from each and collect it in a clean tube (Eluate1) 12. Neutralize the eluate using prestandardised volume of 1 M Tris HCl, pH 9.0 (˜28 μl of 1 M Tris HCl/750 μl) 13. Repeat steps #7-#9 once again using 750 μl of Buffer B, pH 4.0. Neutralize using 1 M Tris HCl, pH 9.0 as above (Eluate 2) 14. Check the pH at this point to make sure that pH is close to 7.0 15. Read absorbance at 280 nm for Eluate 1 and 2 from interface, and pellet (use BSA as standard @1 mg/ml). 16. Dialyze against sterile 0.9% NaCl and concentrate to the required volume 17. Centrifuge at 5000 rpm for 10 min.
[0120] Example embodiments of the present invention have now been described in accordance with the above advantages. It will be appreciated that these examples are merely illustrative of the invention and not limitations thereof. Many variations and modifications will be apparent to those skilled in the art and all such modifications and variations are included within the purview and scope of the appended claims.
REFERENCES
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1. Marshman E, Booth C, Potten C. The intestinal epithelial stem cell. BioEssays 2002, 24: 91-98.
2. Nair P, Lagerholm S, Dutta S, Shami S, Davis K, Ma S, Malayeri M. Coprocytobiology. J Clin Gastroenterology 2003, 36 (Suppl. 1): S84-S93.
3. Vacanti M P, Roy A, Cortiella J, Bonassar L, Vacanti C A Identification and initial characterization of spore-like cells in adult mammals J. Cell Biochem, 2001, 80: 455-460.
4. Shimizu M, Minakuchi K, Tsuda A, Hiroi T, Tanaka N, Koga J, Kiyono H. Role of stem cell factor and c-Kit signaling in regulation of fetal intestinal epithelial cell adhesion to fibronectin. Exp Cell Res 2001, 266: 311-322.
5. Kruger G M, Mosher J T, Bixby S, Joseph N, Iwashita T, Morrison S J. Neural crest stem cells persist in the adult gut but undergo changes in self-renewal, neuronal subtype potential, and factor responsiveness. Neuron, 2002, 35: 657-669.
6. Schon E A, Tales from the crypt. J Clin Invest 2003, 112: 1351-1360
7. Shamblott M J, Axelman J, Wang S, Bugg E M, Littlefield J W, Donovan P J, Blumenthal P D, Huggins G R, Gearhart J D. Derivation of pluripotent stem cells from cultured human primordial germ cells. Proc Natl Acad Sci USA 1998, 95: 13726-13731,
8. Solter D, Knowles B B. Monoclonal antibody defining a stage-specific embryonic antigen (SSEA-1). Proc Natl Acad Sci USA 1978, 75: 5565-5569.
9. Thomson J A, Itskovitz-Eldor J, Shapiro S S, Waknitz M A, Swiergiel J J, Marshall V S, Jones J M. Embryonic stem cell lines derived from human blastocysts. Science 1998, 282:1145-1147.
10. Draper J S, Pigott C, Thomson J A, Andrews P W. Surface antigens of human embryonic stem cells: changes upon differentiation in culture. J Anat 2002, 200: 249-258.
11. Vassilieva S, Guan K, Pich U, Wobus A M. Establishment of SSEA-1 and Oct-4-expressing rat embryonic stem-like cell lines and effects of cytokines of the IL-6 family on clonal growth. Exp Cell Res 2000, 258:361-373.
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This invention relates to the discovery of autologous stem cells of gastrointestinal origin in fecal matter. More particularly, the invention relates to the isolation and propagation of said stem cells in continuous culture. Furthermore, the invention describes a method of directing and converting these gastrointestinal progenitor stem cells into immunoglobulin producing cells that secrete autologous antibodies to an antigen. In addition, the invention describes a method of isolating antibodies secreted by said immunoglobulin producing cells. The invention also describes a method of generating a lineage of antibody producing cells by growing said progenitor stem cells isolated from fecal matter on a feeder layer of tumor cells.
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CROSS- REFERENCE TO RELATED APPLICATIONS
Notice: More than one reissue application has been filed for the reissue of U.S. Pat. No. 6 , 114 , 397 . The reissue applications are U.S. patent application Ser. Nos. 11 / 581 , 734 ( the present application ) , filed Oct. 16 , 2007 , and 10 / 806 , 088 , filed Mar. 22 , 2004 . U.S. patent application Ser. No. 08 / 379 , 872 , filed Jan. 27 , 1995 , issued as U.S. Pat. No. 6 , 114 , 397 , which is a divisional of U.S. patent application Ser. No. 07 / 551 , 353 , filed Jul. 12 , 1990 , issued as U.S. Pat. No. 5 , 385 , 936 .
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is related to the use of gossypol and related compounds as anti-tumor agents effective against human cancers including, but not limited to, adrenocortical carcinoma, uterine, cervical, ovarian and testicular carcinoma, breast cancer, and carcinoid tumors.
2. Description of the Related Art
Gossypol is a double biphenolic compound derived from crude cottonseed oil which has been shown to inhibit spermatogenesis, and which has been used extensively as a male contraceptive in China.
While gossypol has been shown to retard the growth of some cancers in nude mice, its effects vary widely from species to species (Qian, S Z (1984) Ann. Rev. Pharmacol. Toxicol. 24: 329-60; Kim et al. (1984) Contraception 312: 5966-72). The effect of gossypol on the mitochondrial accumulation of rhodamine has been shown to be lower in magnitude in human cells than in rat testicular tumor cells (Tanphaichitr et al. (1984) Biol. of Reprod. 31: 1049-1060). Furthermore, closely related compounds such as mitotane (ortho-para′-DDD), a biphenolic compound which has been used to treat adrenal cancer, are only of limited effectiveness in treating cancer in humans. In addition, the side effects produced at the doses required for response can be debilitating, and include anorexia, nausea, vomiting, and dizziness. Conventional chemotherapy such as with cytoxan, adriamycin, 5FU, and other agents has a low response rate, and side effects such as hair loss, bone marrow suppression, nausea, vomiting, and heart failure. Clearly, an alternate or adjuvant therapy with less toxic side effects is desirable.
The use of gossypol and related compounds as anti-tumor agents against cancers in humans has yet to be reported.
SUMMARY OF THE INVENTION
The present invention relates to the use of compounds with the following formula:
in the treatment of human cancer, including treatment of adrenal, ovarian, thyroid, testicular, pituitary, prostate, and breast tumors, as well as other types of tumors.
Pharmaceutical compositions useful in the present method of treatment include the formulation of gossypol and gossypol acetic acid, which contain both the positive and negative enantamers of gossypol, and formulations containing only one enantamer, as well as any physiologically acceptable salts, for either enteral or parenteral use. Such compositions also include those containing gossypolone. These compounds may be used alone, in combination with one another, or in combination with other conventional chemotherapeutic pharmaceutical compositions. The invention also includes the use of any metabolic products generated from gossypol which have anti tumor activity.
As compared to conventional therapies, the use of gossypol and the related compounds noted above to treat human cancers is associated with milder side effects. These include mild fatigue, muscle tremor, dry mouth, dry skin, and occasional nausea. These are well tolerated, and patients are able to continue their normal activities. In addition, conventional chemotherapeutic agents are associated with a high degree of drug resistance. As discussed below, anti-tumor gossypol therapy has been demonstrated to be effective in patients who exhibit resistance to conventional anti-tumor agents.
As gossypol is taken up into a number of human endocrine tissues, including the adrenal gland, testis, ovary, uterus, thyroid and pituitary, it can be used in the treatment of cancers of these organs, and against carcinoid tumors which are tumors of neuroendocrine tissue which may be located in the lung, pancreas, or gastrointestinal tract.
As previously noted, gossypol has been found to retard the growth of some cancers in nude mice. However, its effects vary widely from species to species. It could not be assumed, therefore, that the anti-cancer effects seen in animals would be seen in humans. A further unexpected feature associated with the use of gossypol to treat cancer in human subjects as opposed to that in animals is that in the latter, higher doses of gossypol (e.g., 0.8 or 1.6 mg/mouse) have been shown to be lethal (Rao et al. (1985) Cancer Chemother. Pharmacol. 15: 20-25), negating any potential benefit of the drug in slowing cancer growth and prolonging survival. The present inventors have shown that the anti-tumor effect of gossypol in humans occurs at doses which are approximately one tenth of those effective in animals, i.e., 1 mg/kg/d vs. 10 mg/kg/d. Toxicity in humans begins to occur at doses greater than 1-2 mg/kg/d. Therefore, the studies of gossypol in animals do not make the use of gossypol for the treatment of cancer in humans, at appropriate doses, obvious in the latter.
Existing therapies for the treatment of human tumors, including adrenal, ovarian, thyroid, testicular, pituitary, prostate, and breast tumors, are multiple, including 5-fluorouracil, adriamycin, cytoxan, cisplatin, etoposide, suramin, and ortho-para′DDD (mitotane). These agents have a partial response rate of less than 20% for adrenocortical carcinoma, and less than 50% for other cancers. The toxicity of these agents, which is not exhibited by gossypol, includes myelosuppression, nausea, vomitting, anorexia, hair loss, cardiac failure and neurotoxicity. Thus, there is a need for anti-tumor agents with less toxicity which have activity against these tumors, and others, which are resistant to existing agents.
Gossypol is a human anti-tumor agent which causes fewer side effects than such existing treatments.
Accordingly, it is an object of the present invention to provide a method for treating cancer in a human, which comprises administering to the subject an anti-cancer effective amount of gossypol, gossypol acetic acid, or gossypolone.
Another object of the present invention is to provide a method for treating cancer in a human which comprises administering to the subject an anti-cancer effective amount of gossypol, gossypol acetic acid, or gossypolone, and an anti-cancer effective amount of 5-fluorouracil, adriamycin, cytoxan, cisplatin, etoposide, suramin, mitotane, or other conventional chemotherapeutic agent, or combinations of these compounds.
A further object of the present invention is to provide a pharmaceutical composition comprising an anti-cancer effective amount of gossypol, gossypol acetic acid, or gossypolone, and an anti-caner effective amount of the compounds listed above, or combinations of these compounds.
Further scope of the applicability of the present invention will become apparent from the detailed description and drawings provided below. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features, and advantages of the present invention will be better understood from the following descriptions taken in conjunction with the accompanying drawings, in which:
FIG. 1 shows the effects on proliferation of SW-13 cells of 0, 0.5, 5, and 50 uM gossypol during prolonged exposure. SW-13 cells were seeded (1×10 4 cells) into 25 cm 2 tissue culture flasks in Dulbecco's minimal Eagle's medium supplemented with fetal calf serum (10%), 100 ug/ml streptomycin, 100 units/ml penicillin, and 2 mM glutamine. Exposure to 5 and 50 uM gossypol inhibited cell proliferation.
FIG. 2 shows the effect of gossypol on the cumulative surface area of SW-13 human adrenocortical carcinoma in nude mice. Gossypol and placebo were given one month after the injection of tumor cells. Gossypol (mg/kg/day): ▪, ◯; ▪, 30.
DETAILED DESCRIPTION OF THE INVENTION
Media, Reagents, and Cells
Dulbecco's minimal Eagle's medium, fetal calf serum, glutamine, penicillin, and streptomycin were purchased from Quality Biological, Inc. (Gaithersburg, Md.); Hanks' balanced salt solution and trypsin-EDTA were obtained from Gibco Laboratories (Grand Island, N.Y.). 1,6-Diphenylhexatriene and tetrahydrofuran were from Aldrich Chemical Co., Inc. (Milwaukee, Wis.). Gossypol and gossypol acetic acid were gifts from the National Research Institute for Family Planning (Beijing, China). The established line of small cell human adrenocortical carcinoma (SW-13) was purchased from the American Type Culture Collection (Rockville, Md.).
In Vitro Gossypol Treatment
Cell Proliferation
Sw-13 cells were seeded in a 25-cm 2 tissue culture flask (Costar, Cambridge, Mass.) at densities of 1×10 4 cells/5 ml of Dulbecco's minimal Eagle's medium, supplemented with 10% fetal calf serum, 100 ug/ml streptomycin, 100 units/ml penicillin, and 2 mM glutamine. The cells were grown in a humidified, 37° C. incubator with a 5% CO 2 /95% air atmosphere. A gossypol stock solution in absolute ethanol was added to the culture medium to yield final concentrations of 0, 0.5, 5, and 50 uM gossypol with a 0.1% final ethanol concentration. After 1, 2, 4, or 6 days of incubation, the culture medium containing a few floating cells was removed. Adherent cells were typsinized (0.1% trypsin, w/v) and counted using a hemocytometer. Cell viability was determined by trypan blue exclusion.
As shown in FIG. 1 , exposure of SW-13 cells to 5 and 50 uM gossypol inhibited cell proliferation.
In Vivo Gossypol Treatment
Nude Mice
Nude mice (Charles River, Kingston, N.Y.) weighing 20-35 g were caged in a temperature-controlled (26-28° C.), 12 h/12 h light/dark animal room. A microporous cage bonnet served as an effective protective barrier between the animal and the outside environment. In addition, the room was continuously purged with High Efficiency Particle Attenuator-filtered air. The cages, feeders, and water bottles were designed to make standard mouse chow and water readily available while minimizing the opportunity for the transfer of communicable pathogens.
Transplantation of SW-13 Cells
Forty-nine adult male nude mice weighing 20-24 g were divided into two groups of 24 for control and 25 for gossypol treatment. Gossypol acetic acid was suspended in 75% ethanol for 24 h, then evaporated in vacuum chamber with desiccant, and finally suspended in sterilized 0.25% carboxymethylcellulose carrier. The gossypol-treated group received 30 mg gossypol/kg body weight/day via an orogastric tube. Control mice were fed an equal volume of carrier. Body weights were measured weekly. At the end of the first week of gossypol treatment, 2×10 6 SW-13 cells were injected s.c. on the back of these mice, which continued to receive gossypol or carrier for 5 additional weeks. Tumor surface areas (length×width, cm 2 ) were measured daily. After 5 weeks, the animals were decapitated.
Another experiment was designed wherein 48 adult male nude mice weighing 25-35 g were injected s.c. with 2×10 6 SW-13 cells. One month later, the animals were divided into two groups of 24. There were 7 nude mice without visible tumors in each group. The gossypol treated animals received 30 mg gossypol acetic acid/kg body weight/day whereas control animals were fed an equal volume of carrier. Body weigths and tumor sizes (lengths×width, cm 2 ) were measured weekly. During the 12th week of treatment, 5 control animals died. Since it appeared unlikely that the remaining control animals would survive for another week, they were then sacrificed. Autopsies were performed on all animals including those that died during the study period. Internal organs were examined for the presence of gross tumor.
Statistical Analysis
Data are expressed as the mean±SD unless otherwise indicated. Statistical comparisons were made using an unpaired Student's t test.
Effect of Gossypol on SW-13 Tumor Bearing Nude Mice
In this experiment, nude mice had been given s.c. injections of SW-13 adrenocortical carcinoma 1 month prior to initiation of the treatment with either gossypol or carrier.
During the subsequent 12 weeks of treatment, there were 10 deaths in the control group: 4 had apparent ascites, were jaundiced, and had large intraperitoneal tumors; 2 suffered from hind leg paralysis due to a tumor metastatic to the spinal column; 2 animals had small tumors, but both showed significant weight loss; 2 had demonstrated neither visible tumors nor an obvious cause of death. In contrast, only two deaths were observed in the gossypol-treated group, one of them having ascites while the other had no apparent tumor at autopsy. Each treated mouse in the group received a total dose of 81.9 mg gossypol during the 12-week period.
As in the previous study, 12 weeks of gossypol treatment had no significant effect on body weights. At the end of the study period, the body weights in both groups were 32.2±3.8 and 30.9±3.6 g for the control and gossypol-treated groups, respectively. After 12 weeks of treatment, the tumor prevalence had risen from 71 to 83% in the control group, while the gossypol-treated group exhibited a decrease in tumor prevalence from 71% to 54%. This was accompanied by the death of 41.6% of the controls and 8.3% of the gossypol-treated group (Table 1).
TABLE 1
Effect of gossypol on tumor prevalence and mortality in mice
having preexisting tumors
Control (%)
Gossypol (%)
Prevalence
Total
Prevalence
Total
Week
of tumor
deaths
of tumor
deaths
0
71
0
72
0
1
75
0
63
0
2
83
0
50
0
3
83
0
54
0
4
83
0
50
0
5
83
0
58
0
6
83
0
58
0
7
83
8.3
58
0
8
83
8.3
58
0
9
83
12.5
54
0
10
83
16.7
54
0
11
83
20.8
54
0
12
83
41.6
54
8.3
The mean tumor sizes of the control and the gossypol treated groups were shown as a function of duration of treatment in Table 2. The slight decline in the mean tumor size observed towards the end of the study period was due to the fact that the majority of the control mice that died during the study has large tumors.
TABLE 2
Effect of gossypol on mean tumor size
Mean tumor size (cm 2 ) (mean ± SE)
Week
Control
Gossypol
0
0.09 ± 0.02
0.08 ± 0.02
1
0.22 ± 0.05
0.07 ± 0.02
2
0.28 ± 0.06
0.12 ± 0.04 a
3
0.35 ± 0.07
0.15 ± 0.05 a
4
0.50 ± 0.11
0.20 ± 0.07 a
5
0.66 ± 0.17
0.28 ± 0.08 a
6
0.87 ± 0.22
0.32 ± 0.10 a
7
0.97 ± 0.25 (n = 23)
0.38 ± 0.12 a
8
1.16 ± 0.33 (n = 22)
0.45 ± 0.14 a
9
1.07 ± 0.34 (n = 20)
0.50 ± 0.15 a
10
1.14 ± 0.36 (n = 20)
0.59 ± 0.18 a
11
1.39 ± 0.41 (n = 19)
0.68 ± 0.21 a
12
0.96 ± 0.21 (n = 15)
0.81 ± 0.25 (n = 22)
a P < 0.05, control compared to gossypol treated group; n = 24 unless otherwise indicated.
The total tumor burden of the two groups rose during the treatment period, the controls reaching a value twice that of the gossypol group at the 12th week (FIG. 2 ).
Treatment of Human Metastatic Adrenal Cancer
Previous medical therapy for metastatic adrenocortical carcinoma has been largely unsuccessful. Based on the growth inhibitory effect of gossypol on SW-13 human adrenocortical tumors in vivo in nude mice, discussed above, the effect of oral gossypol treatment on metastatic adrenal cancer in a human patient was investigated.
A 36 year old man presented with a left sided adrenocortical carcinoma, 26×13 cm, invading the kidney and inferior vena cava. Surgical excision of all visible tumor was performed, and the patient was started on mitotane postoperatively. Pulmonary metastases were found six months later, which were resected. Six month following thoracotomy, multiple hepatic metastases were found. His tumor progressed despite treatment with Suramin and adriamycin/VP16.
At the time of gossypol treatment, the patient had nocturnal dyspnea requiring supplemental oxygen therapy, markedly decreased exercise tolerance, persistent abdominal pain, and pedal edema. Physical examination revealed a cushingoid man with a blood pressure of 150/90, bilateral tender gynecomastia, a liver span of 14 cm, abdominal distension and fluid wave, and bilateral pitting edema to the knee.
Gossypol acetic acid, 10 mg compressed tablet, was given orally at a dose of 20 mg/d which was increased by 10 mg/d every three days to a dose of 50 mg/d.
During gossypol treatment, the patient experienced fatigue, xerostomia, tremor, and trasnminitis. After three weeks of gossypol treatment, CT scans showed complete resolution of pulmonary metastases and greather than 50% decreased in the size of the hepatic metastases, and an improvement in abdominal pain, ascites, and pulmonary function.
A summary of the results obtained in this and other human subjects during a phase I clinical trail of oral gossypol for the treatment of metastatic adrenocortical carcinoma is presented in Table 3.
TABLE 3
Summary of Preliminary Results of Phase 1 Clinical Trial of
Oral Gossypol for Adrenocortical Cancer
Age/Sex
Site
Dose
Duration
Level
Side Effects
Response
36/M*
Lung
40-60
28
463
Xerostomia
Partial
Liver
mg/d
weeks
ng/dl
Fatigue
Response
(*Patient
Gyneco-
described
mastia
above)
Trans-
aminitis
26/M
Lung
70
3
1,025
Xerostomia
Pro-
Liver
weeks
Nausea
gression
Trans-
aminitis
52/F
Abdo-
40
6
444
Xerostomia
Partial
men
weeks
Fatigue
Response
Nausea
34/M
Abdo-
40-50
12
291
Xerostomia
Stabili-
men
weeks
Fatigue
zation
Liver
Nausea
27/M
Abdo-
50
6
229
Xerostomia
Pro-
men
weeks
Fatigue
gression
Pelvis
Of these five patients, two exhibited partial tumor responses, one has stable disease, and two showed tumor progression.
Pharmaceutical Compositions and Modes of Administration of Gossypol and Related Compounds
The method of the present invention includes the administration of gossypol, gossypol acetic acid, or gossypolone, alone or in combination with one another and/or other conventional chemotherapeutic agents, and a pharmaceutically acceptable excipient, to a human subject.
In the methods according to the present invention pharmaceutical compositions containing compounds according to the present invention are administered in an effective amount to a human host for the treatment of a variety of human cancers including adrenal, ovarian, thyroid, testicular, pituitary, prostate, and breast cancer.
In administering gossypol and related compounds for the treatment of cancer by the methods of the present invention, certain pharmaceutical compositions, doses, routes of administration, and desired blood levels may be employed. These are summarized in the table below. In each case, the indicated dose and blood level are approximate, e.g., for oral administration of gossypol acetic acid(+)-compressed tablet, the does may be from about 40 to about 100 mg/d, and the desired blood level may be from about 400 to about 800 ng/dl.
TABLE 4
Pharmaceutical Formulations, Doses, Routes of
Administration, and Effective Blood Levels of
Gossypol and Related Compounds for the Treatment
of Human Cancer.
Formulation
Route
Dose
Blood Level
Gossypol acetic acid
Oral
40-100
mg/d
400-800
ng/dl
(+)-compressed tablet
Gossypol acetic acid
Rectal,
40-140
mg/d
400-1000
ng/dl
(+)-suppositories
vaginal
Gossypol(+)-PVP and
Parent-
1-2
mg/kg/d
400-1000
ng/dl
physiologic salts
eral
Gossypol acetic acid
Oral
40-100
mg/d
400-800
ng/dl
(x)-compressed tablet
Gossypol acetic acid
Rectal,
40-140
mg/d
400-1000
ng/dl
(x)-suppositories
vaginal
Gossypol(x)-PVP and
Parent-
1-2
mg/kg/d
400-1000
ng/dl
physiologic salts
eral
Gossypol(−)-tablet
Oral
20-100
mg/d
200-1000
ng/dl
Gossypol(−)-
Rectal
40-140
mg/d
200-1000
ng/dl
suppositories
Gossypol(−)-PVP and
Parent-
1-2
mg/kg/d
200-1000
ng/dl
physiologic salts
eral
Gossypolone tablet
Oral
50-200
mg/d
400-1000
ng/dl
Gossypolone
Rectal,
50-200
mg/d
400-1000
ng/dl
suppositories
vaginal
Gossypolone PVP and
Parent-
1-5
mg/kg/d
400-1000
ng/dl
physiologic salts
eral
When administered orally, the drug may be taken in divided doses, two to three times a day.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
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A method for treating cancer in a human, which comprises administering to the human subject an anti-cancer effective amount of a compound selected from gossypol, gossypol acetic acid, gossypolone, metabolites thereof, or physiologically acceptable salts thereof. Also included is a method for treating cancer in a human which comprises administering to the human subject an anti-cancer effective amount of any of the compounds listed above in combination with an anti-cancer effective amount of other conventional chemotherapeutic agents. Finally, the invention also encompasses a pharmaceutical composition comprising an anti-cancer effective amount of gossypol, gossypol acetic acid, or gossypolone, and an anti-cancer effective amount of a conventional chemotherapeutic agent, or combinations of the latter.
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BACKGROUND OF THE INVENTION:
1. Field of the Invention
The present invention relates to an apparatus for varying the speed of copies, such as signatures or folded flat products, of the kind that are produced and processed in a folding system, for instance.
European Patent EP 0 498 068 B1 relates to a folding system in which the folded copies are transported via a conveyor device, conveyor drums and belts. A high-speed first belt configuration, containing upper and lower belts, is provided, and the folded copy is conveyed between these belts. A conveyor drum configuration that can be driven at variable speed is also provided, with upper and lower conveyor drums which are precisely in phase with one another during their rotation and which engage the folded copy, brought from the first belt configuration, in the region of its leading edge and transported onward. A slow second belt configuration is also provided, which contains upper and lower belts that engage the folded copy, brought from the conveyor drums, by its leading edge and transport it further. The upper and lower conveyor drums have recesses on their circular circumference, and parts of the conveyor drums of large diameter are formed by a rubber coating, and to meter the force between the conveyor drums, at least one shaft is pivotable by control elements.
European Patent EP 0 256 795 B1 discloses an apparatus for processing sheets that includes a device which can receive the sheets, moving at a first speed, and transports them to a conveyor configuration which is driven at a markedly different speed. The device includes a first rotatable drive element for speeding up and slowing down the sheets, so that they can be transferred to the conveyor configuration at the proper speed. The first drive element is driven by a mechanism that includes a planetary gear which includes a sun wheel. A planet wheel is disposed such that in operation it revolves around the sun wheel. A first rotary element is mounted outside the axis of the planet wheel but is rotatably driven by the orbiting planet wheel, and the first drive element is coupled for the revolution by a motion of the first rotary element. The first drive element is supported rotatably on the sun wheel axis and on the other side of the sun wheel. The second drive element is coupled in a manner fixed against relative rotation by one or more second rotary elements, which are disposed such that they execute a rotary motion in the opposite direction from the motion of the first rotary element, or of each first rotary element, as applicable. The second drive element is mechanically coupled with a counterweight, which is provided in order to compensate for changes in inertia that are transmitted to the first drive element. The configuration is such that the drive elements follow a specified speed and acceleration profile, which repeats periodically.
In both of the embodiments disclosed in the above references, uncontrolled braking, a loss of delivery precision, and damage to the folded copies can occur, and this is especially true at high processing speeds and with extremely lightweight printed materials. The limitations described are sometimes made even worse if the folded copies can be grasped simultaneously by two conveyor configurations in conflict with one another, such as one conveyor configuration for higher speeds and another conveyor configuration for lower speeds. The leading-edge region of the folded copy can for instance already have entered the braking device while the trailing region of the folded copy is also being thrust into the braking device by the conveyor configuration for high speeds, which can cause buckling of the folded copy. This is in fact attained in the version according to the European Patent EP 0 498 068 B1 by use of a cyclical variation of the angular speed of conveyor rollers, in order to achieve a continuous deceleration of the folded copy. But the variable speed change causes dynamic and constantly changing stresses on the components, which can impair the mechanical reliability of the component units.
SUMMARY OF THE INVENTION:
It is accordingly an object of the invention to provide an apparatus for varying the speed of copies which overcomes the above-mentioned disadvantages of the prior art devices of this general type, in which the forces of inertia, occurring upon braking of flat products, are reduced as much as possible so that only the mass of the particular folded copy to be braked at a given time generates delay forces.
With the foregoing and other objects in view there is provided, in accordance with the invention, an apparatus for varying a speed of flat products, containing a higher-speed conveyor configuration having conveyor rollers and belts defining a conveyor path for transporting flat products between the belts of the higher-speed conveyor configuration; a slower speed conveyor configuration having belt rollers and belts defining a conveyor path for further transporting the flat products between the belts of the slower speed conveyor configuration; and a configuration of rotational bodies having liner sections disposed in the conveying path of one of the higher-speed conveyor configuration and the slower speed conveyor configuration, the liner sections being in contact with only one product of the flat products at a time for altering a speed of the one product.
In further features of the concept on which the invention is based, a first conveyor configuration, disposed downstream of a copy-guiding cylinder, includes an upper section and a lower section. The first conveyor configuration is provided with high-speed conveyor belts, in whose conveying path deceleration rollers are received. The high-speed conveyor belts are driven via drive shafts integrated in their path of revolution. The paths of revolution of the high-speed conveyor belts gradually diverge, in the direction of conveyance of the copies, so that grasping of the copies by deceleration rollers is possible precisely at the time when the copies are released by the high-speed conveyor belts. At the contact point of the annular segments, their circumferential speed is very close to the speed of the high-speed conveyor belts. In a similar way, the slow conveyor belts can engage the signatures before their trailing portion is released by delay belts, since the circumferential speed of the slow conveyor belts is very close to the circumferential speed at the contact point of the two annular segments at the braking roller.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in an apparatus for varying the speed of copies, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS:
FIG. 1 is a diagrammatic, side-elevational view of a folding system with copy delivery systems disposed one above the other according to the invention;
FIG. 2 is a detailed, side-elevational view of an outlet region of a high-speed copy conveyor configuration, in which devices for slowing down a speed of the copies are received;
FIGS. 3 a - 3 d are side-elevational views of various angular positions of an eccentrically supported deceleration system;
FIG. 4 is a longitudinal sectional view of a drive mechanism of the deceleration system;
FIG. 5 is a speed graph for the deceleration; and
FIG. 6 is a speed graph of the deceleration system with a different length of liner sections from that shown in FIG. 5 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In all the figures of the drawing, sub-features and integral parts that correspond to one another bear the same reference symbol in each case. Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is shown a side view of a folding system with copy delivery systems located one above the other.
A web 2 of material, entering the folding system via a folding hopper 1 , is guided via pairs of tension rollers 3 , 3 ′ and 4 , 4 ′ to a needle cylinder 7 . Perforating cylinders 5 , 5 ′ may be received between the pairs of cylinders 3 , 3 ′ and 4 , 4 ′; they perforate the web 2 of material in such a way that trapped air cushions can escape more easily, to improve the precision of folding. Along with the needle cylinder 7 , which receives a number of needles 6 , 6 a, 6 b and 6 c, a cutting cylinder 9 is provided, which is equipped with cutting blades 8 , 8 ′ in order to cut separate copies from the incoming web 2 .
Although a folding system with needles is used, the invention can be employed equally well in a needleless folding system, before the copies are delivered to a bucket wheel configuration, as is also the case in open-sheet crosswise cutters, devices for cutting to size within in-line finishing systems, and in sheet-fed rotary printing presses, or in photocopiers. Not only can copies be braked but they may also be subjected to acceleration, or they may be changed from a formation in which they lie end to end to a formation in which they are conveyed in an imbricated stream.
Along with the sets of needles 6 a, 6 b and 6 c, folding blades 10 a, 10 b and 10 c are received on the needle cylinder 7 . With these blades 10 a-c, the copies received on a circumference of the needle cylinder 7 can be thrust into folding jaws 11 a, 11 b and 11 c and also 11 d of a folding jaw cylinder 12 , so that in this way they can be folded crosswise once or multiple times.
Downstream of the folding jaw cylinder 12 , the continuously formed stream of folded copies divides into an upper and a lower feeding stream. The folding jaw cylinder 12 is followed by one upper section 34 and one lower section 35 formed of high-speed conveyor belts 14 , 15 . Deceleration cylinders or deceleration rollers 22 , 23 ; 24 , 25 , respectively, are integrated in the upper and lower sections 34 , 35 . In a variant embodiment of the invention, the deceleration cylinders or deceleration rollers 22 , 23 ; 24 , 25 can also be located outside the respective upper and lower sections 34 , 35 . Slower conveyor belts 36 , 37 ; 38 , 39 are connected downstream of the respective upper and lower sections 34 , 35 . In the conveying path of these respective slow conveyor belts 36 , 37 and 38 , 39 , an upper and lower second longitudinal folder 13 , 13 ′ is provided which provides the folded copies with a second longitudinal fold and introduces them into bucket wheels, for instance, below, through which the thus-folded copies can then be transported onward and optionally processed further as well.
As can also be seen from the view in FIG. 1, the upper section 34 includes the high-speed conveyor belts 14 , 15 , while the lower section 35 includes the high-speed conveyor belts 16 , 17 . First and second tension rollers 18 , 19 are integrated into the path of the respective high-speed conveyor belts 14 , 15 of the upper section 34 ; in the lower section 35 , the tension rollers are identified by reference numerals 20 and 21 . The deceleration rollers 22 , 23 ; 24 and 25 of the upper and lower sections 34 and 35 , respectively, are provided with respective liner sections 60 , 61 , which do not cover an entire circumference of the deceleration rollers 22 , 23 , 24 , 25 . The high-speed conveyor belts 14 , 15 ; 16 , 17 spread open somewhat in their part pointing toward the slower conveyor belts 36 , 37 ; 38 , 39 , and as a result the high-speed conveyor belts 14 , 15 , 16 , 17 move precisely far enough out of the plane in which the copies are transported that the copies, once they have been grasped by the deceleration rollers 22 , 23 ; 24 , 25 , are engaged solely by these rollers and have no further contact with the high-speed conveyor belts 14 , 15 , 16 , 17 . The high-speed conveyor belts 14 , 15 , 16 , 17 are driven, by drive shafts 30 , 31 for the upper section 34 and drive shafts 32 , 33 for the lower section 35 , at a speed that matches the conveying speed of the copies at the folding jaw cylinder 12 . By this configuration (see also FIG. 2 ), the spacings between individual engagement points of the copies in the various conveyor configurations and braking systems can be selected precisely such that the copies are each engaged by one of the conveying and braking systems, while the rear portions are still held over a length of approximately 20 mm. The transitions that occur between the individual conveyor configurations could also be embodied by a different course of the slow conveyor belts 36 , 37 about the tension rollers 18 , 19 ; it would also be conceivable to mount guide baffles extending horizontally.
In the folding system combination, shown in FIG. 1, the two second longitudinal folders 13 and 13 ′ are employed, in order on the one hand to reduce their mechanical strains in operation and on the other for the sake of reliably managing the product stream to be processed at full load. Since the two second longitudinal folders 13 , 13 ′ operate at a lesser speed than the crosswise folding cylinders, the conveying speed of the copies that are to be folded longitudinally must be slowed down. The folding system configuration shown allows production in the magazine mode, if the copies taken from the folding jaw cylinder 12 are carried parallel by both of the sections 34 , 35 , or production in the tabloid mode, if only the upper section 34 or only the lower section 35 carries the copies onto delivery.
The view in FIG. 2 shows in more detail the outlet region of the high-speed conveyor belts 14 , 15 —here showing the upper section 34 , for instance—within which a device for varying the speeds of the copies is integrated. In an embodiment not shown in detail here, the device for varying the speed may also be located outside the delivery region of the high-speed conveyor belts.
A copy that has passed from the circumference of the folding jaw cylinder 12 to the upper section 34 is engaged by the high-speed conveyor belts 14 , 15 . The copy passes through the first and second tension rollers 18 , 19 of the upper section 34 and is taken over at the same time by the liner sections 60 , 61 , where its trailing end leaves the nip between the tension rollers 18 , 19 of the upper section 34 . Since downstream of the nip between the first and second tension rollers 18 , 19 the high-speed conveyor belts 14 , 15 gradually diverge, the copies are no longer touched by the belts 14 , 15 and can be braked by the liner sections 60 , 61 received on the deceleration rollers 22 , 23 . The release of the copies by the deceleration rollers 22 , 23 ; 24 , 25 takes place at the same moment when the leading edge of the copies is engaged by the slow conveyor belts 36 , 37 , which revolve around the receiving rollers 26 , 27 . The system formed by the slow conveyor belts 36 , 37 transports the copies to the respective second longitudinal folders 13 , 13 ′, as already described in conjunction with FIG. 1 . By use of the successive, adapted release of copies and the simultaneous release of copies by the preceding conveyor configuration, a conflict-free continuous deceleration of the copies can be achieved.
FIG. 2 furthermore shows a possibility for positioning the upper deceleration roller 22 against the deceleration roller 23 located beneath it; the rollers are each provided with the aforementioned liner sections 60 , 61 . The upper deceleration roller 22 is received pivotably on a support 66 by way of a journal 65 . The support 66 may be moved up and down in the direction of the double arrow. In the position shown, the support 66 rests on an adjustable stop 67 . By use of a control cylinder 62 , articulated on a control journal 64 of the support 66 , the force prevailing in the gap between the liner sections 60 and 61 can be adjusted. Also by use of the control cylinder 62 , supported in an abutment 63 , the accessibility to the high-speed conveyor belts 14 , 15 can be improved.
In FIG. 2, driving gear wheels 44 and 45 are shown, by way of which the deceleration rollers 22 , 23 are driven. As will be described in further detail in conjunction with FIG. 4 below, portions 57 and 59 with toothing on the inside and outside are provided on the deceleration rollers 22 , 23 , respectively, and the meshing of these portions 57 and 59 with one another can impose a relative speed on the jackets of the deceleration rollers 22 , 23 ; 24 and 25 with respect to the shafts on which they are received. The gear wheels 44 , 45 mesh with the gear wheels 42 , 43 ; see FIG. 4 . It can be seen from FIG. 2 that the deceleration rollers 22 , 23 are located at a nip that slowly opens, since the high—speed conveyor belts 14 , 15 are gradually diverging, and thus the copies are released by the high-speed conveyor belts 14 , 15 shortly after being taken over by the deceleration rollers 22 , 23 . The copies are released by the high-speed conveyor belts at the moment of transfer to slow conveyor belts 36 , 37 . The shafts 30 , 31 serve to deflect the high-speed conveyor belts 14 , 15 and the slow conveyor belts 36 , 37 and to minimize the spacing that has to be spanned between the two conveyor systems. For spanning the distance between the conveyor systems, stationary guides may also be provided, or the slow conveyor belts 36 , 37 can also be guided for deflection about the tension rollers 18 , 19 .
In FIGS. 3 a - 3 d, the transfer of a folded copy 100 by the pair of deceleration rollers 22 , 23 is shown.
In the state shown in FIG. 3 a, the folded copy 100 , which is transported with the folded edge leading in the direction of conveyance, is engaged by the liner sections 60 , 61 when the folded copy 100 leaves the gap between the cylinders 18 , 19 (FIG. 2 ). The folded copy 100 is engaged by the liner sections 60 , 61 at the conveying speed of the high-speed conveyor belts 14 , 15 ; in this case, this is the moment when the points 0 and 0 ″ of the liner sections 60 , 61 are vertically opposite one another. In FIG. 3 a, the shaft segments 52 , 54 and their offset position from one another are also shown. The continuous braking of the folded copies 100 begins in FIG. 3 a. In FIG. 3 b, it persists, and in the view in FIG. 3 c it ends. In this process, the engagement point between the liner sections 60 , 61 shifts continuously from 0 ″ in FIG. 3 a to p″ in FIG. 3 b and finally to 0 ″ in FIG. 3 c. In FIG. 3 c, the folded copy 100 has undergone enough braking that the folded edge is just about to be grasped by the slow conveyor belts 36 , 37 . In FIG. 3 c , the folded copy 100 leaves the gap at 0 ″ between the liner sections 60 , 61 at the speed of the slow conveyor belts 36 , 37 . In FIG. 3 d , the folded copy 100 has left the engagement point at Q″ and is now subjected solely to being grasped; by the slow conveyor belts 36 , 37 , since it has been completely released by the liner sections 60 , 61 .
FIG. 4 shows the drive configuration of the deceleration rollers in longitudinal section.
A crankshaft-like shaft 50 contains a first shaft segment 52 . 1 with an axis of rotation 52 , a cranked portion 54 with an axis 54 ′, and a second shaft segment 52 . 2 with the aforementioned axis of rotation 52 . Corresponding to the upper crankshaft 50 is a lower crankshaft 51 , which likewise has a first portion 53 . 1 with an axis of rotation 53 , a cranked portion 55 with an axis 55 , and a second portion 53 . 2 with the axis of rotation 53 . The two crank-shaft-like shafts 50 , 51 are rotatably supported in side walls 70 , 71 of the folding system. The deceleration rollers 22 , 23 are rotatably supported on the crankshafts 50 and 51 . They move by their eccentricities 54 ′, 55 ′. The portions 52 . 1 , 54 , 52 . 2 and 53 . 1 , 55 , 53 . 2 , which represent the crankshafts 50 , 51 , respectively, are driven by a train of gear wheels 42 , 44 , 45 and 43 , while jackets 200 , 201 of the two deceleration rollers 22 , 23 are driven by a set of inner and outer teeth 56 , 58 and 57 , 59 , respectively. Via a parallel train of wheels, including the gear wheels 46 , 48 , 49 and 47 , the internal teeth 56 , 57 provided with a sleeve mounting are driven, so that the external teeth 58 , 59 that mesh with them can rotate relative to the offset shaft segments. The crank shafts 50 , 51 are driven in such a way that they rotate counter to the conveying direction of the copies 100 , while the jackets 200 , 201 of the deceleration rollers 22 , 23 move about the offset shaft segments 54 , 55 in the conveying direction of the folded copies 100 . As also seen in FIG. 4, the liner sections 60 , 61 are mounted in strip-like form side by side on the circumference of the jackets 200 , 201 of the deceleration rollers 22 , 23 , so that braking—or if desired, after suitable repositioning, acceleration—of even relatively narrow folded copies 100 can be achieved.
The annular speed of the jackets 200 , 201 of the deceleration rollers 22 , 23 relative to the crank shaft 50 amounts to twice the angular speed of the crankshaft 50 relative to the side walls 70 , 71 . The linear speed of the outer diameter of the deceleration roller 22 and the liner section 60 is determined from the following equation: V = ω ( R + 2 e cos ω t ) , e = e 1 + e 2 with e 1 = e 2
where
R stands for the radius of the configuration of the deceleration roller 22 and the liner section 60 ;
e 1 is the eccentricity between the axis 52 of the shaft segments 52 . 1 , 52 . 2 and the offset axis portion 54 ;
e 2 is the eccentricity between a geometric center 80 (see FIG. 3 d ) between the liner sections 60 , 61 on the deceleration rollers 22 , 23 and the axis of rotation 54 ′, 55 ′ of the annular liner sections 60 , 61 on the deceleration rollers 22 , 23 ;
ω is the absolute value of the angular speed of the crank shafts 50 relative to the side walls 70 , 71 , and
t stands for time.
During one complete revolution of the deceleration rollers 22 , 23 relative to the side walls 70 , 71 (two revolutions in terms of the crank shaft 50 ), the linear speed of the outer diameter of the configuration containing the deceleration roller 22 and the liner section 60 has a course represented by one complete sinusoidal curve from A′ to C′ (see FIG. 5) and in the process reaches the maximum value and the minimum value once each.
The half A′B′ of the full cycle A′C′ is utilized to decelerate one folded copy 100 . To that end, only the half of the circumference of the jackets 200 , 201 of the deceleration rollers 22 , 23 or 24 , 25 is provided with respective liner sections 60 , 61 .
From the speed graph in FIG. 5, it can be seen how the braking of the folded copies 100 is performed. At a length of the liner sections 60 , 61 on the roller jackets 200 , 201 in FIG. 5 that corresponds to approximately half the circumference of the deceleration rollers, the portion of the sinusoidal curve from A′ to B′ can be used to brake the folded copies 100 . In graph A, A designates the entry speed of the folded copies. The folded copies 100 are grasped at the speed A′ before they are braked down, in accordance with the sinusoidal course of the curve, to the speed B′ and are transferred at the speed B to the slow conveyor belts 36 , 37 . The synchronization of the angular speed with the conveying frequency of the folded copies 100 is done such that the crankshafts 50 , 51 , or the offset shaft segments 54 , 55 , execute one complete revolution while one folded copy is being transported from the high-speed belts 14 , 15 to the slow-speed belts 36 , 37 . Alternatively, in the case where shorter folded copies 100 are being processed, the crankshafts 50 , 51 and 54 , 55 can be rotated at twice the speed, as briefly described above, while only one folded copy 100 is being transported from the high-speed conveyor belts 14 , 15 to the slow conveyor belts 36 , 37 . In that case, the deceleration device performs one complete revolution without affecting the folded copy 100 . FIG. 6, finally, shows an embodiment of the apparatus with liner sections 60 ′, 61 ′, in which as shown in graphs B, C, only a portion of the sinusoidal speed course of the deceleration rollers is utilized for braking, as may be required for instance with relatively short lengths of folded copies 100 . It is also possible to connect a plurality of devices 22 , 23 ; 24 , 25 for varying the speed in series, in order to achieve a targeted deceleration and/or to create an imbricated stream of copies.
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An apparatus for varying a speed of flat products. The apparatus has a first, higher-speed conveyor arrangement containing conveyor drums and belts, and a second, slower speed conveyor configuration containing belt rollers and belts, in which the flat products are each transported between the belts of the first and second conveyor configurations. A pair of rollers with recesses is provided on the circumference in the conveying path of one of the two conveyor configurations). Rotational bodies move about their respective eccentric axes that in turn are located on crankshafts. The crankshafts rotate on axes with reference to the frame walls, and the rotational bodies and the crankshafts move at a constant angular speed omega.
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BACKGROUND OF THE INVENTION
The present invention relates to laundry appliances, particularly clothes washing machines. More particularly, the present invention relates to a device and method for optimizing the rotational speed of a washing machine tub during the spin cycle so as to minimize washing machine vibration.
A tuned vibration absorber mounted to a clothes washer has been found to effectively reduce machine vibration. The vibration absorber is tuned to reduce machine vibration when the tub is rotated over a range of speeds and is most effective when it vibrates out of phase with the vibration of the washing machine. Such a vibration absorber is described in applicant's co-pending application Ser. No. 08/996,755, filed Dec. 23, 1997.
One difficulty with a vibration absorption system is that the tuned frequency of the absorber is dependent upon the mass attached to the absorber, the spring rate of the springs, the amount of clothes in the tub of the washing machine, floor conditions, and other installation conditions. Consequently, the optimum operational rotational speed for the tub varies from machine to machine, installation to installation and cycle to cycle. Thus, it is not sufficient to preset the controls of the washing machine to spin the tub at a certain rotational speed. For these reasons, there is a need for a device and method of determining the optimum rotational speed of the tub during each spin cycle to best utilize the vibration absorber and minimize machine vibration.
A general object of the present invention is the provision of an improved automatic washing machine.
A further object of the present invention is the provision of an automatic washing machine which determines the optimum rotational speed for the tub during each spin cycle.
A further object of the present invention is the provision of a method for determining the optimum rotational speed for the tub during each spin cycle.
A still further object of the present invention is the provision of a method for quickly determining the optimum rotational speed of the tub to minimize machine vibration.
These as well as other objects, features and advantages of the present invention will become apparent from the following specification and claims.
SUMMARY OF THE INVENTION
The present invention relates to a method and apparatus for optimizing the rotational speed of a washing machine tub during the spin cycle to minimize machine vibration. The method includes sensing and recording rotational speeds and machine vibrations over a range of rotational speeds to quickly determine the optimum speed. The method preferably includes a period of accelerating the washing machine tub to first locate a maximum vibration value and then an approximate minimum vibration value before the tub is decelerated towards the minimum value to more accurately select a rotational speed which minimizes washing machine vibration. The apparatus includes a variable speed washing machine and an accelerometer to sense machine vibration. The washing machine preferably includes a micro-processor, data storage memory circuitry, and computer software to analyze machine vibration and select an optimum speed to minimize machine vibration.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a washing machine used with the present invention.
FIG. 2 is an enlarged perspective view of an accelerometer used to sense machine vibration during the spin cycle.
FIGS. 3A and 3B show a flow chart of the preferred method used to optimize rotational speed and machine vibration.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention will be described as it applies to its preferred embodiment. It is not intended that the present invention be limited to the described embodiment. It is intended that the invention cover all alternatives, modifications, and equivalents which may be included within the spirit and scope of the invention.
FIG. 1 shows a clothes washing machine 10 having a tub 12 mounted within an enclosure 14. A multi-direction vibration absorber 16 is mounted inside the front door 18 adjacent the tub 12. To practice the invention, it is important that the tub 12 be capable of rotating at different speeds. Thus, a variable speed motor (not shown) is provided to rotate the tub 12. Although FIG. 1 shows a horizontal-axis washing machine, the present invention is also suitable for use with conventional vertical-axis washing machines.
The multi-direction vibration absorber 16 is tuned to vibrate in response to certain frequencies. The vibration absorber 16 comprises generally a mass suspended in the door 18 by a plurality of springs as shown in FIG. 1. The vibration absorber 16 is most effective at absorbing and controlling vibration when it vibrates out of phase with machine vibration. The details of the vibration absorber are disclosed in co-pending application Ser. No. 08/996,755, filed Dec. 23, 1997, which is incorporated by reference.
A control 20 is mounted within a console 22 for controlling the operation of the washing machine 10. An accelerometer 24 as shown in FIG. 2 is interfaced with the control 20 and is used to sense machine vibration. Although the accelerometer 24 can be positioned in a variety of different locations about the washing machine 10, mounting the accelerometer 24 towards the top of the washing machine 10 has been found to produce the most reliable measurements.
As shown in FIG. 2, the accelerometer 24 used with the present invention includes a piezoelectric film 26 with a mass 28 attached to the end of the film 26. The accelerometer 24 is well-suited for measuring vibration, as acceleration and vibration are proportional.
The control 20 of the preferred embodiment uses an 8-bit register to store vibration values to display an integer between 0-255 as a measurement of vibration. The control 20 also houses a micro-processor, data memory circuits and computer software.
A method is provided for determining the optimum rotational speed of the tub 12 at which machine vibration is at a minimum. In general, the computer software program interfaces with the control 20 to direct and monitor the rotational speed of the tub 12. The program reads vibration inputs from the accelerometer as the tub is accelerated over a range of rotational speeds. The program then, based on a comparison of the different vibration measurements, quickly and accurately identifies a range at which vibration is a minimum and directs the variable speed motor to decelerate the tub and focus around this minimum range. After more closely monitoring vibration about the minimum vibration range, the program then directs the variable speed motor to settle in at and maintain a rotational speed at which machine vibration is at a minimum.
The method which has been found most effective in quickly and accurately determining an optimum rotational speed so as to minimize machine vibration is set out in FIGS. 3A and 3B. To aid in the description of the prepared method, each of the nodes are identified by a reference numeral. First, the computer software program monitors whether the washing machine 10 is in the spin cycle (32). Once the washing machine 10 enters the spin cycle, then the variable speed motor is activated to start and accelerate the tub 12 spinning (34). Parameters required for determining optimum values for rotational speed (S) and vibration (V) are initialized (36).
The program then continues to monitor the rotational speed (S) of the tub 12 until it reaches a threshold level (S i ) (see 38, 40 and 42). Experimentation has shown 740 rpm to be a suitable S i under normal conditions. Once the tub 12 reaches this threshold speed (S i ), then vibration values (V) from the accelerometer 24 are read (44). This initial reading sets both initial maximum and minimum vibration values (V max , V min ) (46). The program will continue to update these values as it searches for a final value as described in detail below.
The preferred method first searches for a maximum vibration value (V max ). As acceleration continues, vibration is constantly read and recorded to establish the current maximum vibration value (V max ) (see 48, 50, 52, 54 and 56). The current vibration value (V) is always compared with a maximum vibration value (V max ) which is repeatedly updated (54, 56).
The tub 12 continues to accelerate throughout this initial period while searching for a maximum vibration value. Often machine vibration will be at a maximum just prior to entering a range of minimum vibration; accelerating the tub 12 past these maximum values lessens the effect of these spikes in vibration.
The maximum vibration value (V max ) is used as a benchmark in testing for a minimum vibration value (V min ). The program recognizes a minimum vibration value (V min ) as a vibration value less than the previous V min and less than or equal to one-half of V max (58, 60).
Once the current vibration value (V) reaches a level equal to or greater than twice the minimum vibration value (V min ), or there has been no change in the minimum vibration value (V min ) for 20 rpm, then the program assumes that the tub 12 has accelerated past a true minimum vibration value (62). Once this condition is satisfied, the method begins to search for a more accurate V min and the speed with the minimum vibration value (V min ) (see generally FIG. 3B). During some cycles this condition may not be satisfied before the tub reaches the upper limit of its rotational speed (S f ). In this case, the tub 12 is decelerated from this upper limit S f to fine tune the minimum (V min ) (see 52, 53). That is, the tub 12 can be decelerated without first satisfying the minimum vibration condition if rotational speed reaches a predetermined value (S f ), preferably 850 rpm. It is also possible that the tub will reach an acceptable level of vibration (V a ) before an actual minimum vibration level is found. In this case, the searching method is cut short and the tub 12 set to spin at S a , the rotational speed corresponding to the acceptable level of vibration (V a ) (see 64, 66). In other words, when vibration is sufficiently low at a default high speed, preferably 810 rpm, then the program can break out of the optimization routine.
Tub 12 is incrementally decelerated while searching for a final minimum vibration value (V min ). That is, the tub 12 is stepped through certain rotational speeds in fine tuning the minimum vibration value (V min ). Rotational speed (S) and vibration (V) are recorded (76) as the tub 12 decelerates at increments of 5 rpm (84). The tub 12 is maintained at each increment for a sufficient time, preferably 5 to 7 seconds, to allow vibration to stabilize (74). Once a vibration reading is encountered which exceeds the continuously updated minimum vibration, then the tub is accelerated to the optimum rotational speed (S min ) and the corresponding minimum vibration level (V min ) (see 80, 86 and 88). This minimum vibration level corresponds to the rotational speed at which the vibration absorber 16 is at, or approximately, out of phase with machine vibration. Again, an acceptable vibration value (V a ) can be tested for to short cut the method (78). Also, the search can be stopped when the rotational speed reaches a threshold level (S f ) (78). This method of determining the optimum operational speed quickly reaches a desired setting without spending considerable time in ranges of high vibration.
It should be understood that this method is not dependent upon predetermined hard-coded values. For example, the threshold rotational speed (S i ), constants used to test for a true minimum vibration value (V min ), and rpm increments for decelerating the tub 12 can all be customized based on the size of the washer, type of vibration absorber, market requirements, installation conditions, etc.
It should also be understood that the method of the present invention may be used either with or without a tuned vibration absorber. In either case, the method finds an optimal speed to rotate the tub.
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A method and apparatus for optimizing the rotational speed of a washing machine tub to minimize washing machine vibration. The washing machine uses an accelerometer to sense machine vibration. A computer software program monitors, records, and compares machine vibrations over a range of rotational speeds to determine a rotational speed which minimizes machine vibration.
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BACKGROUND OF THE INVENTION
FIELD OF INVENTION
This invention relates generally to model rockets and, more specifically, to an apparatus and method for a flat-sided model rocket.
BACKGROUND OF THE INVENTION
Model rocketry has long been a popular hobby. Model rockets are relatively simple to construct, decorate, and launch. Model rockets generally consist of a cylindrical rocket body, a top portion or nose cone, a parachute, navigational and stabilizing fins, guides for securing the model rocket to the launching apparatus, and a receptacle at the base of the model rocket to receive a standard model rocket engine. This basic design of the model rocket has remained unchanged for many years.
In general terms, the successful launching and recovery of a model rocket requires several steps. First, the body of the model rocket must be able to receive propelling means--ordinarily an A, B, or C-series model rocket engine that is inserted into the base of the model rocket body. Second, the body of the rocket must have launch guides for securing the model rocket to a launching apparatus during take-off. Third, the body of the rocket must have affixed thereto, generally at the lower end of the body, fins for aligning and stabilizing the rocket during flight. Fourth, the rocket must have a parachute-type recovery system, housed in the body of the model rocket, which permits a parachute to deploy following the rocket's ascent and which allows the rocket to guide gently and slowly back to the ground for re-use. Generally, model rockets have removable top portions--typically called nose cones--which automatically detach from the rocket body during flight to permit the deployment of the parachute at the appropriate time. The nose cone must be secured to the remainder of the rocket body so that it is not lost following detachment and so that it may be recovered with the rest of the rocket. Fifth, the fully-assembled rocket must be connected to a launching apparatus, including an engine igniter, for ignition of the engine and the launching of the model rocket skyward.
For many model rocket hobbyists, actual launching of the model rocket is not a necessary part of their enjoyment. For these individuals, enjoyment comes from constructing and decorating model rockets and perhaps from displaying them. Perhaps because of concern that a valued rocket may be damaged or lost if it is launched, many model rocket hobbyists own rockets that will never experience flight.
Despite its longevity, there are several disadvantages to the conventional model rocket design and, in particular, to the use of a cylindrical rocket body. Proper alignment of fins on a cylindrical rocket body, critical to flight stability and alignment but also important for rocket appearance during display, can be difficult. Moreover, precise decoration of a cylindrical structure--in the form of laser-engraving, painting, or the application of stickers--requires extreme care and effort. This is of particular concern to hobbyists assembling model rockets primarily or exclusively for display purposes. Furthermore, a traditional cylindrical rocket body cannot be shipped through the mail without the use of a box or other large package having significant volume, something that increases the cost of mail shipment of model rockets.
Therefore, a need existed for an apparatus and method for an improved model rocket. The improved model rocket and method must be relatively easy to construct, and must be easier to decorate than existing cylindrical model rockets. In this regard, accurate fin alignment must be made simpler, and decoration of the rocket body--through laser-engraving, painting, and/or the application of stickers--must also be made easier. The improved model rocket and method must also permit the shipping of a model rocket in a substantially flat package having little volume. Finally, the improved model rocket must be capable of being launched and recovered in the manner of traditional model rockets, and must be compatible with existing launching apparatuses and model rocket engines.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved model rocket and method that is compatible with existing launching apparatuses and rocket engines and that may be launched in the manner of traditional model rockets.
It is another object of the present invention to provide an improved model rocket and method that is relatively easy to construct.
It is still another object of the present invention to provide an improved model rocket and method the design of which facilitates alignment of the fins on the rocket body.
It is a further object of the present invention to provide an improved model rocket and method that facilitates decoration of the rocket body through laser engraving and other methods.
It is a still further object of the present invention to provide an improved model rocket and method that permits shipment of the model rocket, prior to construction, in a substantially flat package.
BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS
In accordance with one embodiment of the present invention, an improved model rocket apparatus is disclosed. The apparatus is comprised of propelling means for propelling the model rocket; a rocket body coupled to the propelling means and having at least three flat sides, wherein the rocket body comprises a lower body portion, a middle body portion coupled to the lower body portion, an upper body portion coupled to the middle body portion, and flight stabilizing means coupled to the lower body portion for stabilizing the flight of the model rocket; receiving means in a bottom portion of the rocket body for receiving the propelling means for propelling said model rocket; and means coupled to the rocket body for removably connecting the model rocket to a model rocket launching apparatus.
In accordance with another embodiment of the present invention, an improved method for constructing a model rocket is disclosed. The method comprises the steps of: providing propelling means for propelling the model rocket; providing a rocket body coupled to the propelling means and having at least three flat sides, wherein the step of providing a rocket body further comprises the steps of providing a lower body portion, a middle body portion coupled to the lower body portion, an upper body portion coupled to the middle body portion, and flight stabilizing means coupled to the lower body portion for stabilizing the flight of the model rocket; providing receiving means in a bottom portion of the rocket body for receiving the propelling means for propelling said model rocket; and providing means coupled to the rocket body for removably connecting the model rocket to a model rocket launching apparatus.
The foregoing and other objects, features, and advantages of the invention will be apparent from the following, more particular, description of the preferred embodiments of the invention, as illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the model rocket of the present invention.
FIG. 2 is a cross-sectional view of the model rocket of the present invention in the upright position.
FIG. 2a is a top view of a first cross member located in a top portion of the rocket body of the model rocket of the present invention.
FIG. 2b is a top view of a second cross member located in a top portion of the rocket body of the model rocket of the present invention.
FIG. 2c is a top view of a first cross member located in a bottom portion of the rocket body of the model rocket of the present invention.
FIG. 2d is a top view of a second cross member located in a bottom portion of the rocket body of the model rocket of the present invention.
FIG. 2e is a top view of a third cross member located in a bottom portion of the rocket body of the model rocket of the present invention.
FIG. 2f is a top view of a fourth cross member located in a bottom portion of the rocket body of the model rocket of the present invention.
FIG. 3 is a top view of the rocket body of the model rocket of the present invention, prior to construction.
FIG. 4 is an exploded view of the model rocket of the present invention.
FIG. 4a is a perspective view of a launch guide of the present invention.
FIG. 4b is a top view of the engine lock of the present invention.
FIG. 4c is a top view of a lug of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference number 10 refers generally to the model rocket of this invention. Referring now to FIG. 1, the body of the model rocket 10 is four-sided and is comprised of three sections--a top portion or nose cone 12, a middle portion 14, and a bottom portion 16. Attached to the bottom portion 16 are four fins 18, one fin on each of the four sides of the bottom portion 16. The fins 18 extend outward at a substantially 90 degree angle from each of the four sides of the bottom portion 16, and slant across the four sides of the bottom portion 16. Also attached to the bottom portion 16 are launch guides 20, comprising lugs 20a and eyelets 20b (see FIG. 4a). At the end of the top portion 12 that adjoins the middle portion 14, each of the four sides of the top portion 12 has a triangular-shaped portion cut-away therefrom for decorative purposes. In like fashion, at the end of the bottom portion 16 that adjoins the middle portion 14, each of the four sides of the bottom portion 16 has a triangular-shaped portion cut-away therefrom. As shown in FIG. 1, on the end of the top portion 12 that does not adjoin the middle portion 14, the sides of the top portion 12 narrow and angle inward so as to form a point.
Referring to FIGS. 2a-2f, shown are six cross members 22, 24, 26, 28, 30, and 32. Each of the cross members 22, 24, 26, 28, 30, and 32 is substantially square, with tab ends extending from each of the four sides thereof. Cross members 22 and 24 are located in the top portion 12 of the model rocket 10 (see FIGS. 2 and 4). Cross member 24 has a narrow rectangular-shaped opening 34 in the center thereof, substantially along the diagonal between two of the corners of the cross member 24, for receiving a lug 62 (see FIG. 4C). Cross members 26, 28, 30, and 32 are located in the bottom portion 16 of the model rocket 10 (see FIGS. 2 and 4). Cross member 26 has in the same manner as cross member 24 a narrow rectangular-shaped opening 36 in the center thereof, substantially along the diagonal between two of the corners of the cross member 26, for receiving a lug 62 (see FIG. 4C). Cross member 26 has six triangular-shaped openings 38 in the center thereof, which openings 38 are positioned an approximately equal distance from each other and with a side of each of the openings 38 substantially in a circle around the rectangular-shaped opening 36. Cross member 28 has three triangular-shaped openings 40 in the center thereof, which openings 40 are positioned an approximately equal distance from each other and with a side of each of the openings 40 substantially in a circle around the center of the cross member 28. Cross member 30 has three triangular-shaped openings 42 in the center thereof, which openings 42 are positioned an approximately equal distance from each other and with a side of each of the openings 42 substantially in a circle around the center of the cross member 30. Cross member 32 has a round opening 44 in the center thereof, for receiving the non-igniting end of a model rocket engine.
Referring to FIG. 3, a top view of the body of the model rocket 10, prior to construction, is shown arranged on wooden sheet 46. As shown in FIG. 3, the four sides of the top portion 12 (sides 12a, 12b, 12c, and 12d), the middle portion 14 (sides 14a, 14b, 14c, and 14d), and the bottom portion 16 (sides 16a, 16b, 16c, and 16d) are cut from a thin sheet of wood, preferably with a sealed-CO 2 laser, in such fashion that the sides are not completely severed from the wooden sheet 46, so that these portions of the model rocket 10 can be shipped in one piece and in a flat package to a user, and then popped out by the user for construction. The wooden sheet 46 also includes four fins 18, that are cut from the wooden sheet 46 in the same manners as the sides of the top portion 12, middle portion 14, and bottom portion 16.
As shown in FIG. 3, the four sides 12a, 12b, 12c, and 12d each comprise a substantially rectangular bottom portion and a substantially triangular top portion. At substantially the confluence of the rectangular and triangular portions thereof, each of the four sides comprising the top portion 12 has thereon a narrow rectangular-shaped opening 48, for receiving a tabbed end of cross member 22 (see FIGS. 2 and 4). Each of the four sides comprising the top portion 12 also has thereon, near the bottom of the rectangular portion thereof, a second rectangular opening 50 for receiving a tabbed end of cross member 24 (see FIGS. 2 and 4), which rectangular openings 50 are parallel to the rectangular openings 48. Sides 12a and 12c each have portions cut away along the sides of the rectangular portions thereof, so as to mate with corresponding tabs on sides 12b and 12d. The triangular portions of sides 12a, 12b, 12c, and 12d end substantially in a point.
Still referring to FIG. 3, four sides 14a, 14b, 14c, and 14d are shown, comprising the middle portion 14 of the model rocket 10. Each of these sides is substantially rectangular, with a tab on one long side and a cut-away portion of corresponding size on the second long side. During assembly, the tabbed and cut-away portions are interlocked, so that, for example, the tabbed portion of side 14a interlocks with the cut-away portion of side 14b, while the tabbed portion of side 14b interlocks with the cut-away portion of side 14c.
FIG. 3 also shows four sides 16a, 16b, 16c, and 16d, comprising the bottom portion 16 of the model rocket 10. The four sides of the bottom portion 16 are substantially rectangular in shape, and comprise an upper and lower portion. The upper portion of each of the four sides of the bottom portion 16 contains four parallel, narrow, rectangular openings 52, for receiving tabbed ends of cross members 26, 28, 30, and 32 (see FIGS. 2 and 4). The lower portion of each of the four sides of the bottom portion 16 contains a narrow, rectangular opening 54 in substantially a diagonal orientation for receiving a fin 18 (see FIG. 2). Side 16c contains two additional narrow rectangular openings for receiving lugs 20a (see FIGS. 2 and 4). The sides of the upper portions of sides 16a and 16c are tabbed, and the bottom portions of sides 16a and 16c have cut away portions of substantially the same size. Sides 16b and 16d have corresponding, reversed tabbed and cut away portions, with tabs on the bottom portions and cut away portions on the top portions of sides 16b and 16d. The tabs and cut away portions on the four sides comprising the bottom portion 16 are interlocked during construction.
At the base of each of the sides 16a, 16b, 16c, and 16d, there is a substantially 1-shaped channel 58. After a rocket engine (not shown) is inserted into the bottom portion 16 of the assembled model rocket 10, the rocket engine is secured in position with the insertion into the 1-shaped channels 58 of the tabbed portions of a TEFLON®-coated, substantially round engine lock 60 (see FIG. 4B).
Still referring to FIG. 3, each of the fins 18 is substantially in the shape of a right-angled triangle, with portions cut away from each of the three sides thereof for design purposes. Each of the fins 18 is connected to one of the four sides 16a, 16b, 16c, or 16d by the insertion of a tabbed portion from one of the sides of the fin 18 into an opening 54 (see FIGS. 2 and 4).
Referring again to FIGS. 2a-2f, the cross members 22, 24, 26, 28, 30, and 32--like the portions of the model rocket 10 shown in FIG. 3--are cut from a thin sheet of wood with a sealed-CO 2 laser. The rectangular-shaped openings 34 and 36, the triangular-shaped openings 40 and 42, and the round opening 44 are also cut into the corresponding cross member with a laser. With respect to the triangular-shaped openings 40 and 42 and the round opening 44, these are cut into the corresponding cross member with the laser in such fashion that the wood occupying the opening is not completely severed from the cross member, so that the user can during construction pop out the cut out portions to reveal the openings.
The sides of the top portion 12, the middle portion 14, and the bottom portion 16, and the fins 18, may be decorated with any variety of decorations 62 (see FIG. 1), which can be applied using a sealed CO 2 laser. Portions of the model rocket 10 may also be decorated by painting the rocket and/or by applying stickers thereto.
Construction of the Model Rocket
As is common in the model rocket area, the model rocket 10 of the present invention is designed so that it may be constructed by a model rocket hobbyist. Thus, a user purchasing the model rocket 10 for construction will receive a sheet of wood 46, shown in FIG. 3, with the four sides of the top portion 12, middle portion 14 and bottom portion 16, and the four fins 18. The contents of the sheet of wood 46 are cut into the sheet of wood 46 with a laser so that the pieces are not entirely severed from the sheet of wood 46, but may be easily popped out by a user for construction. The user of the model rocket 10 will also receive cross members 22, 24, 26, 28, 30, and 32; at least two lugs 20a and two eyelets 20b; at least two lugs 62; a shock cord for coupling the top portion 12 and the bottom portion 16 (not shown); and a parachute recovery apparatus (not shown).
A user assembling the model rocket 10 will first glue a lug 62 into the opening 34 in the center of cross member 24 and a lug 62 into the opening 36 in the center of cross member 26, in both instances so that the lug extends entirely through the openings and the bottom portions of the lugs are flush with the cross members. For added strength, it is preferable to first glue two lugs 62 face to face before gluing the lugs 62 into position in the openings 34 and 36. One end of a shock cord, an elastic cord that is standard in the model rocket industry, may be secured to the opening in the lug 62 that has been coupled to the cross member 26.
Next, a user will attach the fins 18 to the four sides 16a, 16b, 16c, and 16d of bottom portion 16, by gluing the tabbed portions of the fins 18 into the openings 54. The user will then take cross members 26, 28, 30, and 32, remove any remaining cut outs in openings 38, 40, 42, and 44, and will glue these cross members into one side of the bottom portion 16 in order, with cross member 26 occupying the highest position and cross member 32 occupying the lowest position. Next, the user will take two eyelets 20b, glue them into two lugs 20a, and glue the assembled apparatus into the openings 56 on side 16c. For added strength, it is preferable to first glue two lugs 20a face to face before inserting the eyelets 20b and gluing the apparatus into position in the openings 56.
Taking the side of the bottom portion 16 with the cross members attached, the user then glues that side to the two sides with the opposite orientation of tabs and openings--for example, if the cross members have been attached to side 16a, side 16a should then be glued to sides 16b and 16d. The remaining side of the bottom portion 16 is then glued to the three assembled sides, so as to complete the construction of the bottom portion 16. As each additional side is added, the tabs of cross members 26, 28, 30, and 32 are glued into the openings 52 in the additional side.
After assembly of the bottom portion 16 is completed, the user then assembles the middle portion 14. To accomplish this, the user glues to the interlocking surfaces of sides 14a, 14b, 14c, and 14d, and attaches each side to the two sides with corresponding tabs and openings. The assembled middle portion 14 is glued into the bottom portion 16. During this assembly step, the unattached end of the shock cord (not shown), is threaded through the middle portion 14 and attached to the lug 62 attached to cross member 24. Also attached to the lug 62 attached to the cross member 24 is a parachute assembly (not shown), of the type commonly used in the model rocket industry. The parachute canopy is housed in the middle portion 14 during the launching of the model rocket 10.
The user next takes one of the four sides comprising the top portion 12, and inserts into the opening 48 thereon a tabbed portion of cross member 22, and into the opening 50 thereon a tabbed portion of cross member 24. Taking the side of the top portion 12 with the cross members attached, the user glues that side to the two sides with the opposite orientation of tabs and openings--for example, if the cross members have been attached to side 12a, side 12a should then be glued to sides 12b and 12d. (As each additional side is added, the tabs of cross members 22 and 24 are glued into the openings 48 and 50, respectively, in the additional side.) The remaining side of the top portion 12 is then glued to the three assembled sides, and the pointed tips of the sides 12a, 12b, 12c, and 12d are secured together so as to form a point and to complete the construction of the top portion 12.
The assembled model rocket 10, which preferably has laser engraved designs 62 of any variety on one or more of the portions thereof, may be painted by the user or may have stickers applied thereto.
To launch the model rocket 10, the user must insert a model rocket engine (not shown) into the open portion of bottom portion 16, and secure the rocket engine into position with a round engine lock 60, the tabbed ends of which engine lock 60 are inserted into the slotted portions of the 1-shaped channels 58. Prior to launching, the top portion 12 must be inserted onto the middle portion 14, with the parachute assembly (not shown) housed in the middle portion 14. The model rocket 10 is then placed onto a launching apparatus (not shown), with the launching rod of the launching apparatus being inserted through the eyelets 20b. The model rocket 10 may then be launched using an igniter of the type common in the industry (not shown).
While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention. In this regard, the number of flat sides may be increased from four or may be reduced to three while still preserving many of the advantages of the present invention.
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The present invention is directed to an apparatus and method a flat-side model rocket. In the preferred embodiment, the model rocket is four-sided, and may be constructed by a user from wooden pieces that are pre-cut and pre-engraved with a sealed-CO 2 laser. The model rocket of the present invention is compatible with existing model rocket engines, launching apparatuses, and parachute-type recovery apparatuses.
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FIELD OF THE INVENTION
This invention relates to an elastic hose that can be snapped onto different sized or shaped faucets, spigots, and showerheads to provide a leak-proof joint therewith, or which can be used as a flexible funnel for a variety of uses.
More specifically, in one embodiment, this invention relates to an elongated elastic hose that can be easily adapted to fit over any size or shape domestic water outlet to substantially silence a leaking fixture or to conduct water from the fixture to a pail or the like which will not fit under the outlet and could therefore not otherwise be filled.
In another embodiment of the invention, the elongated elastic hose is adapted for use as a flexible funnel which can be stretched over different sized or shaped cans and which is easily stored.
BACKGROUND OF THE INVENTION
A common problem which plagues homeowners, apartment dwellers, and the like is a leaky faucet. In addition to the incessant and annoying dripping sound which inevitably accompanies the same, it is often the case that the splash made by the droplets of water dampen or flood the surrounding area. This may result in ruined carpets, floors, and possibly soaking of the ceiling below.
It is often the case in such situations that the proper tools for fixing a leaky faucet are not readily available. Even if these tools were available, in many cases the individual is not mechanically inclined or doesn't have the necessary know-how to fix a leaky faucet. Usually, the faucet leaks until the problem becomes severe enough that a plumber is called. Until the plumber arrives, however, the noise and the mess remain.
There are times during a water shortage, for example, when a homemaker might want to make use of the water leaking from a leaking faucet to water a pet or plants or clean the floor. But, ordinarily, when the droplets are caught in a receptacle, such as a bucket, the droplets make such an irritating noise when they hit the bottom of the bucket, that it is often better to let the leaking water go down the drain.
In addition, there are times when a housewife would like to fill a pail with water from a nearby sink, but finds that the pail will not fit under the faucet. Therefore, she is forced to seek water at a more distant source and must transport a filled container over a considerable distance. This can be extremely tiring where the distance is long and the load heavy. By the same token, transporting a heavy pail of water invariably leads to some water spilling from the pail and causing water damage.
Various attachments for use in conjunction with water outlets are known, the purpose of the majority of them being to permit a sink or bathtub to be filled with water in such a manner that the usual noise associated with running water is virtually eliminated.
For instance, U.S. Pat. No. 1,663,382 discloses a device to silence flowing water from a water outlet which comprises a spirally wound member preferably made of soft fabric which is secured by a collar onto a faucet. In addition to quieting the flow of water, this device also functions to filter the same.
Similarly, U.S. Pat. No. 2,794,200 discloses a shower spray absorber which includes a soft tube of cloth attached to the shower head by a collar so that the spray flow when the shower is turned on may be conducted within the tube.
In U.S. Pat. No. 1,661,704, a water silencer is provided for use when a faucet is turned on which is attached to the faucet without the use of fittings. It comprises a substantially elliptical rubber tube which has an enlarged lower end at the discharge point. At the discharge point, the device is flattened and provided with notches to break up the stream of water.
A device for reducing the sound which occurs when liquid under high pressure flows out of a faucet is disclosed in U.S. Pat. No. 2,194,163. It includes a tubular inner body closed at its lower end with numerous transverse perforations and a concentrically arranged outer tube. By diverting the direction of flow through the perforations and downward, a loss in hydro-static pressure is accomplished, thus making the flow quieter.
All of the above-mentioned devices are directed at silencing or controlling the flow of a stream of water when the faucet is in the open position. Other prior art devices, such as those disclosed in U.S. Pat. Nos. 1,110,959; 1,383,886 and 1,783,492 also address the control of flow of water from an open faucet. These devices fail to provide a solution for the situation which arises when the faucet is shut off and leaks. Moreover, the elasticity of these devices is quite limited. The stretchability of all of these prior art devices is less than 100%, thus they are limited to fit outlets near their original size and shape.
It is therefore an object of the present invention to provide a device which controls the flow of water from a leaky faucet by a simple and inexpensive means.
It is another object of the present invention to provide a device which minimizes the amount of noise which accompanies a leaky faucet.
It is also another object of the present invention to provide a device which makes it tolerable to save some of the water from a leaking facuet so that it can be used.
It is further object of the present invention to provide an elastic hose that is adaptable to establish a gripping, leak-proof connection to a liquid source regardless of its size or shape in order to conduct liquid away from the source without the need for additional parts, such as a collar.
It is a further object of the present invention to provide a device which is elastic and can thereby be extended and adjusted in length to reach an outlet, such as a bucket, etc., in order to collect the water.
It is a further object of the present invention to provide a simple and inexpensive hose that can be connected temporarily to different sized and shaped water faucets to either silence a drip or to divert water into a suitable container.
Another object of the present invention is to provide a flexible hose for temporary use in association with a domestic water outlet which can be folded into a small package and easily stored when not in use.
It is yet another object of the present invention to provide a device which, with simple modifications, can be used for a variety of other functions, for example, as a funnel.
SUMMARY OF THE INVENTION
These and other objects of the present invention are attained by a drainage hose formed of an elastic tube having a central passageway for conducting a liquid away from a source such as a water outlet or tap. The tube is made in three sections which include a funnel shaped upper section, a cylindrical middle section and a smaller cylindrical lower section. The drainage hose is provided with enough flexibility to allow it to be folded into a small package when not in use. The upper opening of the funnel shaped section is wide enough to permit this section to be stretched over a faucet or the like to establish a leak-proof connection therewith. The hose may also be cut through the middle or lower sections to vary the length of the tube, so that water dripping from the faucet may be conducted directly into the drain or to a bucket, etc. Preferably, the hose is made from a thin, balloon-like, latex material, having a stretchability on the order of about 400%-1,000%, and most preferably, about 700%-900%.
The hose is therefore an excellent temporary solution for the problem of controlling the splashing and noise generated from a leaky faucet and the like.
In another embodiment of the present invention, the drainage hose may be adapted for use as a funnel. This is accomplished by using a petroleum resistant, less elastic material and providing a wider mouth and upper portion. In this case, the hose has a stretchability on the order of about 400%-600%. Preferably, this embodiment is a shorter version of the drainage hose described above, but is similar in that it also may be folded into a small package and easily stored when not in use. While flexible funnels have been described in the past, see, e.g., U.S. Pat. No. 135,391, funnels which can be folded into a small package are not previously known.
The funnel described above may be used in situations where it is unlikely that a regular funnel is handy. For instance, it is highly unlikely that an automobile is equipped with a funnel due to its awkward shape and the space it takes up. However, the present funnel may be folded up and stored in a very small area, such as the glove compartment of an automobile. This provides the driver of the automobile with a practical solution to the problems which arise when it is necessary to add oil or antifreeze to the engine. Especially in an emergency situation, it is highly unlikely that a funnel will be handy. The present invention solves this problem by making it practical to have a funnel handy at all times.
Another important feature of the funnel according to the present invention is the fact it may be easily discarded after a single use. After a funnel is used once for a viscous liquid such as oil, it becomes extremely messy. For this reason, it is even less desireable for the average motorist to store a funnel in his car, especially after it has been used. On the other hand, the funnels available to motorists in the past have generally been too expensive for the great majority of motorists to discard after a single use. However, because of the relatively small cost of the present funnel, it is no longer inefficient to discard the same after a single use. In addition, due to the funnel's elasticity, it may be re-folded and stored in the pouch that it was sold in until it can be cleaned up and stored again or conveniently discarded (such as the case when no trash receptacles are readily available).
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of an elastic drainage hose that embodies the teachings of the present invention;
FIG. 2 is a side elevational view of a sink showing the drainage hose shown in FIG. 1 being used to fill a container from the sink tap;
FIG. 3 is a side elevational view in partial section of a bathtub showing the drainage hose in FIG. 1 being used to drain water from a leaking shower head to a drain situated at the bottom of the tub;
FIG. 4 is a side elevational view of a funnel according to the present invention; and
FIG. 5 is a side elevational view showing the funnel in FIG. 4 being used to transfer the contents of an oil can.
DETAILED DESCRIPTION OF THE INVENTION
Turning now to the drawings and, in particular, to FIG. 1, an elastic drainage hose is formed from a single piece of thin latex and is capable of being considerably stretched in all directions without breaking or tearing. The hose has a stretchability on the order of about 400%-1,000%, and preferably about 700%-800%. The hose is tubular shaped throughout and has a circular passageway 11 extending from a top opening 12 to a bottom opening 13 through which any type of liquid can be conducted.
The drainage hose of the present invention is comprised of three contiguous coaxially aligned sections including a funnel shaped upper section 15 which is joined to a cylindrical middle section 16 which, in turn, is joined to a smaller cylindrical lower section 17. Upper section 15 includes a rolled top which makes a reinforced elastic ring 20 which surrounds the opening 12. The wall 21 of the funnel is brought inside the ring.
By stretching the material forming the upper section of the funnel wall 21 and letting it contract around the faucet above the point of drippage, it is possible to vary the size and shape of the top opening. The drainage hose is thus provided with additional adaptability for its attachment to a water fixture, such as a faucet. In this way, the size of the top opening can be varied so that it can be exactly matched to the size of the water fixture so that many different-sized fixtures can be accommodated by a single-sized hose. In other words, "one size fits all".
The funnel of FIG. 1, in an unstretched condition, is about three inches long and has a two inch (seven inch maximum when stretched) top diameter when measured inside the ring. The side wall of the funnel tapers uniformly downwardly toward the middle section of the tube and terminates at the entrance 23 to the middle tube section which is about 1/2 inch in diameter.
By configuring the upper section of the tube in the manner described above, the top of the rubber hose can be conveniently stretched over all faucets, shower heads, etc., that are presently used in the home. The latex balloon-like construction provides sufficient elasticity so that when the funnel is released from a stretched position about the shower head it will contract into conforming contact against the fixture to establish a gripping and leak tight seal. In the event the outlet is smaller than the top opening, the funnel is engaged with the outlet so that the outlet is gripped by the deeper, smaller part of the funnel that will effectively accommodate the outlet.
As previously noted, the middle section of the hose is cylindrical in form and has a diameter of about 1/2 inch, and is preferably about 30 inches long. The middle section is connected to the top of the lower section at a necked down joint 38. The lower section is also cylindrical in form having a diameter of about 1/4 inch and a length of about 30 inches. The overall length of the hose therefore, is over 60 inches which provides more than adequate length so that it can be used for the noted purpose.
The drainage hose of the present invention can also be used as shown in FIG. 2 to convey water from a sink tap 40 into a large container, such as water pail 41 which ordinarily cannot be placed inside a shallow basin 42 beneath the sink faucet 43.
In this type of application, where the faucet outlet is not very wide and the vertical distance to the pail relatively short, the tube can be cut across the upper part of the middle section 16 and the severed part of the tube discarded. This provides the tube with a small 1/2 inch top opening that can be stretch fitted over a small tap to establish a gripping tight connection around the tap. The body of the tube is brought over the rim of the sink and is passed downwardly into the pail. For a hose of the size herein described, a relatively high continuous volume rate of flow can be sustained so that the container is filled in a short period of time. The hose can also be used to fill large containers from small units thereby eliminating the need of having to carry heavy buckets over relatively long distances. Once used, the present device can be easily disconnected from the fixture and stored in a small package until such time as it might be needed again. The hose can, of course, be used in the same manner described in association with FIG. 3 to also collect water from a leaking faucet or shower so that the water can be put to use and thus not wasted.
As should be evident from the disclosure above, the single piece elastic hose of the present invention can be easily stored about a house or apartment so that it will be readily available when an emergency arises. The hose is also adaptable to fit different size and shape outlets such as sink and tub taps or shower heads of all types. The hose efficiently and virtually silently conducts drops from a leaking faucet into an existing drain or into a storage container. It is specifically designed and fitted to control leakage from faucets that are shut off but persist in leaking.
FIG. 3 illustrates the drainage hose of the present invention being used to silence a leaking shower head 34. The head is shown mounted immediately over the drain end 33 of a conventional bathtub 32. As can be seen, water dripping from the head will fall considerable distance before striking the bottom of the tub. As a consequence, the drops hitting the tub produce considerable noise which is extremely annoying. In some cases, the falling droplets can splash over the rim of the tub and thus cause water damage if allowed to continue unabated. As illustrated, the drainage hose 10 is stretched over the shower head 34 and the body of the tube is allowed to hang dow inside the tub. The tube is provided with sufficient body length so that the lower section 17 thereof can be seated upon the floor of the tub with the bottom opening 13 of the tube lying adjacent the tub drain 34. As can be seen, water dripping from the head is conducted quietly down the inside wall of the tube and is passed directly into the drain without splashing or otherwise wetting the surrounding surfaces. The hose can thus be used temporarily to silence annoying and troublesome drips until such time as a plumber is available to repair the leaking fixture. The flexible tube, after being removed from the fixture, can be hung on a hook or folded into a small package and stored until it is again needed.
FIG. 4 illustrates another embodiment of the present invention in which the hose has been adapted to act as a funnel 50. In order to accomplish this result, a number of adjustments are made to the hose. For instance, funnel 50 has a wider mouth than the hose depicted in FIGS. 1-3 because it is made from a petroleum resistant, less elastic material. Moreover, it is made from a less elastic material. The stretchability of funnel 50 is on the order of 400%-600%. Finally, in a preferred embodiment, the funnel 50 is shorter than the hose depicted in FIGS. 1-3 in order to allow the more direct transfer of the liquid from the source to the deposit site.
Funnel 50 is basically comprised of two contiguous coaxially aligned sections including a funnel-shaped upper portion 52 which is joined to a cylindrical lower portion 54. The upper portion 52 of funnel 50 is about 21/2 inches in diameter, while the lower portion 54 is only about 1/2 inch in diameter. The entire funnel 50 is about 12 inches long. Similar to the embodiment of the present invention depicted in FIGS. 1-3, the upper portion 52 includes a rolled top which makes a reinforced elastic ring 56, which surrounds the top opening 58, the upper portion of the funnel wall 60 being attached to ring 56 by any suitable means.
The ring 56 prevents tearing and provides a handle by which the device can be installed, as well as an extra tight grip, so it is less likely to slip when it is used o large containers. Alternatively, it forms a shaped border which can accommodate a variety of liquid dispensers such as the oil can 65 depicted in FIG. 5. The lower opening 69 of funnel 50 can easily be placed into a vessel for receiving the liquid to be transported. For instance, the lower opening 65 can easily be placed within the appropriate opening of an engine block (not shown) in order to convey oil from the oil can 65 into the engine block.
Once again, it is possible to vary the size of the top of funnel 50 by stretch fitting its upper section 52 in order to accommodate different sized containers. Thus, similar to the drainage hose depicted in FIGS. 1-3, "one size fits all". Funnel 50 can be made on the same equipment as the drainage hose depicted in FIGS. 1-3.
While the invention has been described in detail with reference to preferred embodiments, it should be understood that the invention is not limited to those embodiments, and that many modifications and variations will present themselves to those of skill in the art without departing from the scope and spirit of this invention, as defined in the appended claims.
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An elastic hose for conducting a liquid from a source such as a water fixture or a storage container to a delivery site is disclosed. The hose includes an upper funnel-shaped portion and at least one contiguous lower cylindrically-shaped portion. The upper portion may be stretched over a water fixture, a liquid container, or the like to form a gripping leak-proof seal. The hose has a stretchability of about 400%-1,000%. The lower portion is led to a delivery site. The hose is able to conduct liquid from a source to the delivery site without spills or mess. Moreover, in the case of a leaky faucet, the hose eliminates splashing and substantially decreases the noise generated by the leaking water.
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This is a continuation of application Ser. No. 07/352,962, filed May 17, 1990, now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention concerns pneumatic oscillators, especially but not exclusively for the operation of resuscitators and/or ventilators and like devices for inducing or assisting lung function in human patients.
2. Background Discussion
In general, such devices generate a train of pulses of breathable gas that is ducted to a patient, usually via a so-called patient valve and/or an oronasal mask or tracheal intubation device. The generation of the pulse train with pulses at the required intervals and with appropriate tidal flow characteristics requires some form of switching mechanism controlling the flow of breathable gas from a source to the pulse output. Simplicity, reliability and constancy of performance in service, and robustness are dominant criteria in the design of resuscitators or ventilators, especially those intended for use by emergency services such as ambulance crews, or for use in a domestic environment by non-specialist operators.
3. The Prior Art
Pneumatic oscillators exist in various forms and many forms have been applied to this purpose. GB-A-1 533 550 exemplifies one such form of pneumatic oscillator that has been successfully applied in practice but even that oscillator comprises several components and several moving parts, with consequent complexity and cost.
In another form of pneumatic oscillator, a piston or its equivalent is reciprocable to open and close a flow path between a source of pressurized breathable gas and a pulse output. The piston is biassed towards the flow path-closing position and the biassing is supplemented by gas pressure derived from the output of the device. Source gas pressure is applied to the piston in a manner to overcome the biassing so as to cause the piston to move to its flow path-opening position; whereupon the device outputs a gas pressure pulse from which pressure is derived to supplement the biassing and restore the piston to its flow path-closing position. Examples of such an oscillator are disclosed in FR-A-1 530 478 and US-A-3 881 480.
To obtain a snap-action in the opening and closing of the flow path, a poppet valve arrangement is utilised in which a sealing lip coacts, in the flow path-closing condition, with a resilient facing in such a manner as to isolate an area of the piston or equivalent from the gas pressure acting elsewhere. Accordingly, when the flow path is open, gas pressure is applied to a different area than when the flow path is closed with the consequence that there is an abrupt change of effective area exposed to gas pressure at the point of switching, and an abrupt change in the force balance on the piston.
Although an oscillator of this general form exhibits remarkable simplicity and would appear to be eminently suitable for the applications considered, in practice such oscillators have not achieved widespread adoption because the attainment of accurate and reproducible performance characteristic depends critically upon the maintenance of close tolerances in manufacture and even then the characteristics tend to change, unpredictably, in service. The reason for this is that the characteristics are critically affected by the force balance on the piston or its equivalent at the point of switching and this in turn is influenced by a number of factors. One such factor is the relative areas of piston or equivalent exposed to gas pressure at the point of switching, as determined by engagement of the sealing lip of the poppet valve with its resilient facing.
For a good snap-action it is essential that there is minimal leakage across this seal right up to the point of force balance and that at this point, the flow path is opened suddenly and with a force/flow gap characteristic that is stable over long periods and is unaffected by wide ranges of temperatures and duty patterns. There is as a consequence a conflict of design requirements because to obtain good sealing (low leakage) the combination of a resilient facing and a sharply defined lip is desirable. However this combination leads to permanent set indentation and/or cutting of the facing material in service, with consequent deterioration of performance. Accordingly it is usual to depart from the ideal configuration for low leakage by employing a more rounded sealing lip. While this provides good sealing over long periods of service and avoids cutting of the facing material, it brings with it the disadvantage that the line of contact between the lip and the facing material is not sharply defined and varies in service as a result of the facing material becoming permanently indented. Thus the area within the lip tends to change during service and so alter the ratio of the areas that control the force balance at the point of switching.
SUMMARY OF THE INVENTION
In accordance with the invention a pneumatic oscillator of the form discussed is characterised by a poppet valve arrangement that incorporates a sealing lip providing for sharp definition of a line of contact on a resilient facing to define a switching control area and stop means adapted to limit penetration of the facing by the lip in the flow path-closing condition.
Preferably the stop means are associated with the sealing lip and are disposed to coact with the facing adjacent to the line of contact of the sealing lip.
The stop means may take various forms. Preferred forms comprise a ring of castellations concentric with the lip and outboard or inboard thereof so that symmetry is obtained, without the stop means interfering with exposure of the areas outboard and inboard of the lip to operating gas pressures.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is further explained with reference to the accompanying drawings in which
FIG. 1 illustrates diagrammatically the principles of a pneumatic oscillator of the form to which the invention pertains:
FIG. 2 illustrates a typical poppet valve arrangement as hitherto used in such an oscillator;
FIG. 3 illustrates the effect of wear and extended service upon the configuration of the typical poppet valve arrangement illustrated by FIG. 2;
FIG. 4 illustrates a poppet valve arrangement for an oscillator embodying the invention; and
FIG. 5 illustrates on an enlarged scale the nature of the contact between the sealing lip and the facing material in the flow path-closing condition of the poppet valve.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The principle of an oscillator of the form to which the invention is applicable is illustrated diagrammatically in FIG. 1 of the drawings. A piston 1 is reciprocable in a cylinder 2 and is biassed by a spring 3 towards the right as seen in the drawing, to engage a sealing lip 4 surrounding a port 5 in the end of the cylinder 2. In the arrangement shown the port 5 constitutes an outlet port connected to an output line 7 by way of an outlet branch 6.
The outlet branch 6 also connects with a feedback line 8 via a restrictor 9, the feedback line 8 connecting with the end of the cylinder opposite to that containing the port 5. A further restrictor 10 is interposed between the outlet branch 6 and the output line 7.
A further port 11 in the end of the cylinder 2 and outboard of the port 5 serves for the admission of pressurized breathable gas, for instance compressed air or oxygen, to this end of the cylinder 2.
The drawing shows the piston 1 in a flow path-opening position clear of the sealing lip 4. In this position of the piston 1, breathable gas can flow from the source indicated at 12 via the ports 11 and 5 to the outlet branch 6 and thence via the restrictor 10 to the output line 7 and also via the restrictor 9 and the feedback line 8 to the left hand end of the cylinder 2 as seen in the drawing. As a consequence of the flow of gas in the branch 6 and the presence of the restrictor 10, gas flows through the feedback line to the left hand end of the cylinder 2 at a rate controlled by the restrictor 9 and builds up pressure therein that acts on the piston 1 to supplement the force of the spring 3. Eventually the combined effects of the gas pressure and spring 3 cause the piston to move to the right as seen in the drawing, towards the sealing lip 4. As the piston approaches the latter, flow to the outlet branch 6 is restricted and the pressure therein drops so that there is a sudden shift in the balance of forces on the piston 1 and this completes its movement to the right with a snap-action, to engage the sealing lip 4 and thus cut off flow to the port 5 and outlet branch 6.
Pressure in the left hand end of the cylinder 2 then decays by reverse flow of gas from the cylinder through the feedback line and restrictors 9 and 10. When the gas pressure in the left hand of the cylinder 2 has decayed to an appropriate extent, the source gas pressure acting on the annular area of the piston 1 outboard of the sealing lip 4, overcomes the force of the spring 3 and causes the piston 1 to commence to move towards the left as seen in the drawing. As it does so, it opens the pathway to the port 5 and gas flows into the outlet branch 6, building up pressure therein which acts on the central area of the piston 1 to supplement the thrust of the source pressure on the outboard annular area of the piston. There is in consequence an abrupt change in the balance of forces acting on the piston 1 which moves with a snap-action to the position shown in the drawing, whereupon the described cycle repeats with a frequency determined by the relationship between the annular area outboard of the sealing lip 4 and the total cylinder area, the bias force supplied by the spring 3 and the characteristics of the restrictors 9 and 10.
The principles of the operation of this form of pneumatic oscillator may be embodied in various arrangements in practical devices. For instance the restrictor 9 may be replaced by various restrictor/non-return valve networks to achieve particular cycling patterns in the output line and to provide different operator control possibilities. The biassing of the piston may be achieved by means other than a spring: for instance the piston may have different areas effective at its opposite ends so that when both ends of the piston are exposed to equivalent pressures it experiences a net thrust towards the flow path-closing position. The piston may be replaced by one or more diaphragms. Whereas in the arrangement shown the port 5 constitutes an outlet port and the port 11 constitutes an inlet, the converse arrangement is possible. Moreover, the sealing lip 4 may be carried by the piston (or its equivalent) to move therewith and coact with a resilient facing on the cylinder end wall, instead of being carried by the latter as in the illustrated arrangement.
FIG. 2 illustrates a typical poppet valve arrangement in which a sealing lip is defined by an inner cylindrical surface 20 merging with an outer conical surface 21 in a rounded lip surface 22 of relatively small radius chosen to avoid cutting of the resilient facing material 23 under the loads experienced in service. However as a consequence of extended service and as shown in FIG. 3, the facing material 23 takes a permanent indentation or set such that the effective line of contact between the sealing lip and the facing material moves outwardly around the lip surface 22 and towards a point on the surface 21. This has the effect of changing both the inner and the outer effective areas defined by the sealing lip.
For instance if in a new poppet valve the contact line is a circle of diameter 7 mm, the area within the contact line is ##EQU1##
If in service the resilient facing material wears or indents to change the position of the line of contact by as little as 0.1 mm radially, the area within the line of contact becomes ##EQU2## , a change of about 6%. This change in a typical oscillator controlling a resuscitator or ventilator could result in a change of the allowed exhalation time in excess of 10%, which change is unacceptable for most applications.
FIGS. 4 and 5 illustrate the design of a preferred form of poppet valve for an oscillator embodying the present invention. In the poppet valve illustrated in these Figures the sealing lip has a sharp lip surface 32 defined by the junction between inner and outer surfaces 30, 31 disposed with a small included angle. In the illustrated arrangement the outer surface is that of a circular cylinder whereas the inner surface 30 is conical but the converse arrangement can be adopted as can an arrangement in which both inner and outer surfaces are inclined to the axis. However, for best effect the surface on the gas supply side of the lip should be as close to the cylindrical form as practicable.
In accordance with the invention the sealing lip is associated with stop means arranged to limit movement of the sealing lip towards the facing 33 so as to restrict penetration of the facing by the sealing lip, to a predetermined allowable extent.
The stop means may take various forms and may comprise one or more abutments associated with parts carrying the sealing lip and the facing respectively. However it is preferred that the stop means be associated with the sealing lip in a manner to coact with the facing adjacent to the line of contact between the sealing lip and the facing, this arrangement providing the closest control over the penetration of the sealing lip into the facing.
There may be a single abutment associated with the sealing lip but it is preferred, for reasons of symmetry and load distribution, to utilise a plurality of abutments arranged in a ring concentric with the sealing lip.
Thus in the arrangement illustrated in FIGS. 4 and 5, the sealing lip is associated with a ring of castellations 36 concentric with the sealing lip and, in this embodiment, arranged inboard of the latter. However an outboard disposition of the stop means is also feasible. There could be two rings of abutments or castellations, for instance one inboard and the other outboard of the sealing lip.
Preferably the stop means is disposed to coact with the facing in an area thereof that is not active in the switching function, so that any masking of that area by the stop means does not affect the switching function. Moreover, the stop means, While having a contact area that is large in relation to that of the sealing lip, preferably has a contact area that is small in relation to the contact area of the facing region that it engages.
In other embodiments of the invention, the stop means may comprise one or more continuous surfaces concentric with but spaced radially from the sealing lip. However to avoid unwanted effects of masking of the intervening area of the facing, and of gas flows through the small gap between a stop means surface and the facing at the point of switching, gas flow pathways would preferably be provided between the areas inboard and outboard of a continuous stop means surface.
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A pneumatic oscillator especially useful for generating breathable gas pulses in a resuscitator and/or lung ventilator device has a reciprocable piston or equivalent controlling a poppet valve arrangement that includes a sealing lip coacting with a resilient facing. The sealing lip provides for sharp definition of a line of contact on the resilient facing and penetration of the latter by the lip is limited by stop means, preferably abutment(s) coacting with the facing adjacent to the line of contact with the sealing lip. This prevents wear and/or excessive indentation of the facing with consequent shift of the contact line and alteration of the oscillator characteristic with time.
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BACKGROUND
[0001] Wells are generally drilled into the ground to recover natural deposits of hydrocarbons and other desirable materials trapped in geological formations in the Earth's crust. A well is typically drilled using a drill bit attached to the lower end of a drill string. The well penetrates the subsurface formations containing the trapped materials so that the materials can be recovered.
[0002] During drilling or after a well is drilled, various logging instruments are used to collect information about the formation properties. The well may then be completed based on the information collected about the formation to maximize the production efficiency. In the processes of drilling, logging, completion, and production, various tools are used. These tools need to withstand the harsh conditions downhole, which may include temperatures as high as 200° C. and pressures as high as 20,000 psi. Often sensitive parts of the tools are enclosed in chambers (seal housings) that may be filled with liquids (e.g., oil). The part of the tools that exit the enclosed chambers are often protected with seals that isolate the enclosed oil from the outside, while allowing movement (e.g., rotation) of the extruded parts. These seals are often referred to as “dynamic seals” because they seal against a moving part. The following description uses a mud pulse telemetry system as an example to illustrate the present invention.
[0003] FIG. 1 shows a typical drilling system 101 . A drilling rig 102 at the surface is used to rotate a drill bit 107 using a drill string 103 . Using a mud pump 121 , drilling fluid, called “mud,” is pumped to the drill bit 107 through the drill string 103 . The downward flow of mud is represented in FIG. 1 by downward arrow 104 . The mud lubricates and cools the drill bit 107 and then it carries the drill cuttings back to the surface as it flows upwardly through the annulus. The return flow of mud is represented by the upward arrow 106 .
[0004] The drilling system 101 includes a bottom-hole assembly (“BHA”) 110 at the bottom end of the drill string 103 . The BHA 110 includes the drill bit 107 and any sensors, testers, tools, or other equipment (not shown) used in the drilling process. Such equipment may include formation evaluation tools, directional drilling tools, and control circuitry.
[0005] Communication between the driller and the BHA 110 is typically called “telemetry.” The data that are collected by the sensors in the BHA 110 must be relayed to the surface so that the driller will have the data when making decisions about the drilling process. Additionally, the driller must be able to communicate with the BHA 110 so that commands may be sent to the BHA 110 . A “downlink” is a communication from the surface to the BHA. Likewise, an “uplink” is a communication from the BHA to the surface.
[0006] There are various prior art telemetry methods. One class of telemetry methods is called “mud pulse telemetry.” Mud pulse telemetry uses pulses in the mud flow rate or pressure to communicate between the surface and the BHA.
[0007] One method of downlink mud pulse telemetry uses the mud pumps at the surface to control the mud flow rate to the BHA. The flow rate is detected and interpreted by the downlink system. Methods of uplink mud pulse telemetry typically include a pressure modulator in the downhole tool. The pressure modulator creates pressure pulses in the mud flow that may be detected at the surface. A pressure modulator uses a motor or drive mechanism to operate a flow control device to generate pressure pulses in the mud flow. The drive mechanism is enclosed in a seal housing that includes a dynamic seal to allow the drive shaft to exit the seal housing.
[0008] Dynamic seals on downhole tools need to function in a wide range of ambient pressures—from the atmospheric pressure uphole to the high pressure (up to 20,000 psi) downhole. To overcome such challenges, a seal housing is often equipped with a pressure compensation mechanism that permits the pressure inside the seal housing to adapt to the ambient pressure. Prior art pressure compensation mechanisms typically use a piston that is allowed to move in order to change the volume of the seal housing in response to the ambient pressure.
[0009] Due to the limited diameter (hence, the volume) of the downhole tools, the piston mechanism may have to be placed at a distance from the dynamic seal. The distance between the dynamic seal and the pressure compensation mechanism unnecessarily introduces a delay between pressure pulse generation and compensation. It is therefore desirable to have methods and systems that can provide better pressure compensation.
SUMMARY
[0010] In some embodiments the invention relates to a downhole pressure compensation system that includes a seal housing disposed in a downhole tool, a dynamic seal disposed on the seal housing, wherein the dynamic seal seals around a part that is allowed to move relative to the seal housing, and a flexible membrane disposed in a sidewall of the seal housing proximate the dynamic seal.
[0011] In some other embodiments, the invention relates to a method of compensating for a mud pressure signal that includes generating a pressure signal in a mud flow rate, and transmitting the pressure to the inside of a seal housing through a flexible membrane disposed on a seal housing proximate a dynamic seal.
[0012] Other aspects and advantages of the invention will be apparent from the following description and the appended claims.
BRIEF DESCRIPTION OF DRAWINGS
[0013] FIG. 1 shows a cross section of a typical drilling system.
[0014] FIG. 2 shows a cross section of a prior art pressure compensation system.
[0015] FIG. 3A shows one embodiment of a modulator in an open position.
[0016] FIG. 3B shows one embodiment of a modulator in a closed position.
[0017] FIG. 4 shows a cross section of a seal in a prior art pressure compensation system.
[0018] FIG. 5 shows a cross section of a mud port and a piston in a prior art pressure compensation system.
[0019] FIG. 6 shows a graph of a mud pressure signal and a compensated pressure signal in a prior art pressure compensation system at 24 Hz.
[0020] FIG. 7 shows one embodiment of a pressure compensation system in accordance with one embodiment of the invention.
[0021] FIG. 8 shows a graph of a mud pressure signal and a compensated pressure signal in a pressure compensation system operating at 24 Hz in accordance with an embodiment of the invention.
DETAILED DESCRIPTION
[0022] Embodiments of the invention relate to pressure compensation systems suitable for applications involving high frequency and high amplitude pressure pulses. Certain embodiments of the present invention relate to a system for high frequency/high amplitude pressure compensation. Other embodiments of the invention may relate to a method of compensating a high frequency/high amplitude pressure signal. For clarity, the following description uses a mud pulse telemetry generator to illustrate the present invention. However, one of ordinary skill in the art would appreciate that embodiments of the invention are not limited solely to mud pulse generator. Instead, embodiments of the invention are generally applicable in any pressure compensation applications, particularly for downhole tools. The invention will now be described with reference to the figures.
[0023] FIG. 2 shows a cross section of a mud pulse modulator 201 that may be used to send an uplink signal. The mud pulse modulator 201 includes a rotor 202 and a stator 203 . The rotor 202 rotates with respect to the stator 203 to generate the pressure pulses, as will be explained with reference to FIGS. 3A and 3B . The rotor 202 is coupled to a shaft 205 that connects the rotor 202 to a drive assembly that includes a gear assembly 206 and a servo motor 207 . The shaft 205 passes through a seal housing 216 , and seals 204 seal around the shaft 205 to isolate the working oil inside the seal housing 216 from the mud that is outside the seal housing 216 . Typically, a servo motor 207 is used to enable precise control of the rotor 202 , although other drive mechanisms may be used.
[0024] FIGS. 3A and 3B show one example of a modulator 301 that may be used to generate a pressure pulse. In FIG. 3A , the modulator 301 is in an open position. The stator 304 includes four passages, such as passage 305 , that enable mud to flow through the modulator 301 . In the open position, the rotor 306 is positioned so that it does not cover the openings 305 in the stator 304 . The rotor includes cuts 307 that enable the openings 305 to be uncovered in the open position. In the open position, the modulator 301 enables free flow of mud through the modulator 301 .
[0025] FIG. 3B shows a modulator 301 in a closed position. Flaps 308 on the rotor 306 partially cover the openings 305 in the stator 304 . This presents an impediment to the flow of mud, and the pressure increases so that a constant flow rate of mud is maintained. FIGS. 3A and 3B shows the modulator 301 in open and closed positions, but those having ordinary skill in the art will realize that the rotation of the rotor 306 causes the modulator 301 to modulate between the open and closed positions.
[0026] Referring again to FIG. 2 , the seal 204 provides a dynamic seal to isolate the oil inside the seal housing 216 from the mud outside. The oil inside the seal housing 216 lubricates and protects the drive mechanisms. In order for the seal 204 to maintain its integrity and proper function under conditions ranging from the atmospheric pressure (when it is uphole) to the downhole pressure (up to 20,000 psi), a pressure compensation mechanism is needed so that the pressure differential across the seal 204 is minimal, regardless of the outside pressure. The pressure compensation mechanism typically comprises a piston that is able to move freely along a cylinder to alter the volume of the oil chamber in response to the outside pressure, ensuring that the pressures on both sides of the piston are substantially the same regardless of the outside pressure. A pressure compensation mechanism typically used in a downhole tool will be described in detail later.
[0027] Referring to FIG. 2 again, the modulator 201 creates pressure pulses that travel uphole, or to the left in FIG. 2 . For example, when the modulator 201 is in a closed position (e.g., as shown in FIG. 3B ), a high pressure pulse will travel up hole. In the closed position, a reduction in pressure is experienced on the downhole side of the modulator 201 . Conversely, when the modulator 201 is in an open position (e.g., as shown in FIG. 3A ), a reduction in pressure is experienced uphole, and an increase in pressure is experienced on the downhole side of the modulator 201 .
[0028] FIG. 4 shows a close-up of the shaft 205 that drives the rotor ( 202 in FIG. 2 ) and a seal assembly 404 , 406 that seal around the shaft 205 . The outer seal 404 is a rotating seal that rotates with the shaft 205 , and inner seal 406 is a stationary seal that also seals around the shaft 205 , but it remains fixed with the seal housing 216 . In operation, the rotor 202 is driven by the drive shaft 205 to rotate with respect to the stator 203 , generating pressure pulses in the mud. These pressure pulses are experienced on the outboard side of the inner seal 406 , in area 410 , for example. The pressure pulses created by the modulator can have an adverse effect on seal performance and seal life. Thus, it is often desirable to use a pressure compensation system to balance the oil pressure on the inboard side of the seal 406 .
[0029] A pressure compensation system balances the oil pressure inside the seal housing 216 (i.e., in area 412 ) so that is will fluctuate with the borehole hydrostatic pressure and the mud pressure signal outside the seal housing 216 (i.e., in area 410 ). This will ensure that the pressure differential across the inner seal 406 will remain close to zero at all times. A balanced pressure will reduce the leakage across the seal 406 and, more importantly, increase the life of the seal.
[0030] Referring back to FIG. 2 , a pressure compensation system provides pressure compensation using a port 208 , a mud chamber 210 , and a piston 212 to achieve pressure compensation inside the drive housing 209 that is in fluid communication with the stator seal 406 . The piston 212 is free to move along the length of the mud chamber 210 so that the pressures on both sides of the piston 212 are substantially the same, which in turns ensures that the pressures across the stator seal 406 are substantially the same, regardless of the outside pressure. The pressure compensation system is placed at a distance to the seal 406 due to the limited diameter (volume) of the downhole tool. The distance between the pressure compensating piston and the seal 406 necessarily creates a time delay between the pulse generation and compensation. The pressure pulses from the mud pulse modulator 201 need to travel through the mud outside the tool between the modulator 201 and the mud port 208 . At the mud port 208 , the change in pressure may enter the mud chamber 210 in the drive housing 209 . Typically, the pressure compensation piston 212 , located inside the drive housing 209 , is able to move (e.g., along the length of the mud chamber 210 ) in response to pressure differences between the mud in the mud chamber 210 and the oil pressure inside the drive chamber 209 . The oil pressure behind the piston 212 is then relayed to the seal 406 to counter (compensate) the change in pressure on the other side of the seal 406 . However, due to the time needed for the change in pressure to travel this distance, the pressures across the seal 406 are not equalized during the delay. If the pressure on the outside is greater than the pressure on the inside, then the fluid on the outside (e.g., mud) may leak into the oil housing, resulting in damages to the parts to be protected.
[0031] FIG. 5 shows a close-up view of the mud port 208 , the mud chamber 210 , and the pressure compensation piston 212 . A change in pressure enters the drive housing 209 through the port 208 and is transmitted into the mud chamber 210 . The change in pressure then acts on the piston 212 , causing a corresponding change in the oil pressure. An increase in mud pressure will cause the piston 212 to move upwardly and increase the oil pressure. Similarly, a decrease in mud pressure will cause the piston 212 to move downwardly and decrease the oil pressure.
[0032] In some embodiments, a piston 212 may be coupled to a spring 214 . The spring 214 applies a force to the piston 212 that would create a slightly higher pressure in the oil chamber than the pressure in the mud chamber 210 . Thus, if there were to be any leakage across the inner seal ( 406 in FIG. 4 ), the leakage would be of oil out of the seal housing ( 216 in FIG. 4 ) and not of mud into the seal housing.
[0033] Referring again to FIG. 2 , an increase of pressure in the mud chamber 210 will cause the piston 212 to move, thereby transmitting the pressure increase through the drive chamber 209 and to the inboard side of the seal ( 406 in FIG. 4 ). This type of pressure compensation system requires that a pressure pulse travel from the modulator 201 to a port 208 in the drive housing, before returning through the interior of the drive housing 209 .
[0034] The time delay, t, between the mud pressure pulse and the resulting pulse in the oil is related to the distance that the pulse must travel and the speed of sound in the particular fluid through which the pulse is traveling. The time delay may be quantified as shown in Equation 1:
t = ( d o + d m ) C m + d m C m + d o C o Eq . 1
where d o is the length of the oil cavity in the tool (shown in FIG. 2 ), d m is the length of the mud cavity in the tool (shown in FIG. 2 ), C o is the speed of sound in the oil, and C m is the speed of sound in the mud.
[0035] The first term in Equation 1 represents the time it takes the mud pressure pulse to travel through from the seal and mud pulse modulator area to the mud port (e.g., 208 in FIG. 2 ). This length is represented by the sum of the length of the oil chamber d o and the length of the mud chamber d m . The sum is divided by the speed of sound in mud C m , the medium through which the signal travels in this direction. The middle term represents the time it takes the pressure pulse to travel back through the mud chamber (e.g., 210 in FIG. 2 ) inside the drive housing. This time is represented by the length of the mud chamber d m divided by the speed of sound in mud C m . The last term in Equation 1 represents the time it takes the pressure pulse to travel through the oil chamber of the drive mechanism—the length of the oil chamber d o divided by the speed of sound in oil C o .
[0036] More sophisticated mud pulse telemetry systems use higher pulse frequencies to increase and optimize the data transmission rate of the telemetry system. These can range from less than 1 Hz to 24 Hz. The higher frequencies have created problems with the response time of pressure compensation systems. At higher frequencies, the time that it takes for the pressure signal to travel to the mud port (e.g., 208 in FIG. 2 ), travel back through the mud chamber (e.g., 210 in FIG. 2 ), and travel back through the oil chamber to the inboard side of the seal (e.g., 204 in FIG. 2 ) may be a significant portion of one cycle. The time delay creates a compensated pressure that is out of phase with the modulator pressure.
[0037] FIG. 6 shows a graph of the mud pressure signal 601 along with the compensated pressure signal 602 in the oil on the inboard side of the seal in a prior art pressure compensation system. The signal shown in FIG. 6 is a 24 Hz signal. As shown in FIG. 6 , there is a phase shift between the mud signal 601 and the oil signal, or compensated pressure signal 602 . The compensated signal 602 is delayed from the mud signal 601 , making the compensated signal 602 out of phase with the mud signal 601 . The difference between the mud signal 601 and the compensated signal 602 is plotted at 603 . The pressure difference 603 shown in FIG. 6 may cause the seal (e.g., 406 in FIG. 4 ) to oscillate with the pressure fluctuations (represented by the pressure difference curve 603 ). Oscillation of the seal may cause damage to the seal that will reduce seal life. Additionally, when the pressure on the outside of the seal is higher than that on the inside, mud may leak into the housing, leading to damages of the seal and the drive mechanism.
[0038] FIG. 7 shows one embodiment of a pressure compensation system in accordance with one embodiment of the invention. The seal housing 716 includes a flexible membrane 710 that enables pressure to be transmitted to the interior of the seal housing 716 . When the pressure outside of the seal housing 716 increases, the flexible membrane 710 flexes inwardly, thereby increasing the pressure on the inboard side of the seal 706 . Conversely, when the pressure outside of the seal housing 716 decreases, the flexible membrane 710 flexes outwardly, thereby decreasing the pressure on the inboard side of the seal 706 .
[0039] The flexible membrane 710 is located in the seal housing 716 to be proximate the seal 706 . This significantly reduces the distance over which the pressure signal must be transmitted to compensate the pressure on the inboard side of the seal 706 . By reducing the distance over which the signal must travel, the response time of the pressure compensation system is significantly increased.
[0040] In the embodiment shown, the flexible membrane 710 is coupled to a passageway 712 that leads to the interior of the seal housing 716 . In other embodiments, a flexible membrane may be in contact with both the mud outside the seal housing and with the oil inside the seal housing without the need for a passage way, i.e., the flexible membrane 710 may form part of a wall of a seal housing.
[0041] The flexible membrane 710 may be made of any material that will flex enough to transmit pressure to the interior of the seal chamber 716 . For example, the flexible membrane 710 may be constructed of an elastomer or a thin piece of metal. Additionally, the geometry (i.e., the shape and size) of the membrane 710 may be selected based on the particular application or operating condition. For example, the membrane 710 may extend around the entire circumference of the seal housing 716 , forming a frustoconical shape. In other embodiments, the membrane 710 may form a window over only a portion of the seal housing 716 . The geometry and the material of the membrane 710 may be selected for specific applications and design considerations.
[0042] Those having ordinary skill in the art will realize that any number of variations of a flexible membrane may be possible without departing from the scope of the invention. For example, this description makes reference to a “seal housing,” which houses and protects the seals, and a “drive housing,” which houses and protects the drive mechanisms for the modulator. In practice, however, these may not be separate components. That is, a drive mechanism housing may also house and protect the seals.
[0043] Additionally, a flexibly membrane may be constructed of a material having enough strength that the flexible membrane may be in direct contact with both the mud on the outside of the seal housing and the oil on the inside of the seal housing. In such an embodiment, a passage (i.e., passage 712 ) between the flexible membrane and the interior of the seal housing may not be necessary. Other variations of a flexible membrane may be devised that do not depart from the scope of the invention.
[0044] FIG. 8 shows a graph of a mud pressure signal 801 along with a compensated pressure signal 802 , using a pressure compensation system in accordance with the invention. The compensated pressure signal 802 closely matches the mud pressure signal 801 created by the modulator (e.g., 202 in FIG. 2 ). Plot 803 shows the difference between the mud pulse signal 801 and the compensated pressure signal 802 . The difference 803 shows a constant, slight excess pressure on the inside of the seal housing. This slight excess pressure is typically provided by a spring mechanism to ensure that no mud will leak into the housing.
[0045] Embodiments of the invention use flexible members close to the dynamic seals to provide better pressure compensation and improved seal lives. One of ordinary skill in the art would appreciate that the flexible membrane pressure compensation mechanism in accordance with the invention may be used together with the prior art piston pressure compensation mechanism. For downhole tools, the combined use of these two types of pressure compensation mechanisms is particularly beneficial—the piston pressure compensation mechanism ensures that the protected oil chamber can be used in a wide range of pressure (e.g., from the atmospheric pressure to the downhole pressure), while the flexible membrane mechanism ensures that high frequency and/or high magnitude pressure pulses are effectively compensated.
[0046] It is noted that a piston arrangement is one possible prior art pressure compensation system that could be used with embodiments of the invention. Other pressure compensation systems may include a bellows system or a bladder system. Those having ordinary skill in the art will be able to devise other types of pressure compensation systems that may be used with embodiments of the invention.
[0047] Certain embodiments of the present invention may present one or more of the following advantages. A pressure compensation system in accordance with the invention may decrease the phase shift of a compensated pressure pulse. At a high modulator frequency, the reduced phase shift may reduce the pressure differential across a seal in the modulator system.
[0048] Advantageously, a pressure compensation system in accordance with the invention may reduce or prevent oscillations of a seal in the modulator system. Reduced oscillation may decrease seal leakage and increase seal life. The ability of a pressure compensation system to compensate for high frequency pressure telemetry signals enables the use of still yet higher frequencies in a telemetry. Advantageously, a pressure compensation system in accordance with the invention may enable faster communication in a telemetry system. Similarly, embodiments of the invention may provide benefits to other tools that include pressure compensation mechanisms. It is noted that there are devices that can emit high frequency and high magnitude pressure changes other than the telemetry devices described above and the scope of this invention should not be limited as such.
[0049] While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.
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A downhole pressure compensation system includes a seal housing disposed in a downhole tool, a dynamic seal disposed on the seal housing, wherein the dynamic seal seals around a part that is allowed to move relative to the seal housing, and a flexible membrane disposed in a sidewall of the seal housing proximate the dynamic seal.
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CROSS REFERENCE TO RELATED PATENTS
[0001] The priority benefit of U.S. provisional patent application Ser. No. 60/564,839, filed Apr. 23, 2004, is claimed.
BACKGROUND OF THE INVENTION
[0002] The present invention relates generally to electronic security systems and to electronic over-lock systems for self-storage units in particular.
[0003] In the U.S., a burglary currently occurs every 13 seconds. Accordingly, security systems have gained popularity for homeowners and businesses alike. For businesses that lease spaces, a security system is a necessity to compete in the marketplace. Whether it is the lease of apartments, office space, industrial space or self-storage facilities, the ability to attract new customers is greatly dependent upon a reliable security system to protect the tenants' valuable assets.
[0004] For self-storage facilities a reliable security system is important, not only to attract new tenants, but also to retain existing tenants. The term self-storage facility describes one or more freestanding buildings, each having a plurality of individual storage units that are typically rented on a monthly basis. In many of these facilities, tenants are responsible for the security of the units they have rented. Accordingly the tenant will put a padlock on the door to the unit to prevent theft.
[0005] If a tenant becomes delinquent in the payment of rent, the facility manager is required to place a second lock, or “over-lock” on each unit. This over-lock is used to keep the tenant from accessing the unit until the past due rent is paid. There is thus an increased need for decreasing the manpower associated with the application and removal of over-locks and a desire to automate the process. For example, if a typical self-storage facility consists of five hundred units and during any month, there are 15% of the tenants in arrears, the manager of the self-storage facility must place over-locks on the seventy-five units. These over-locks must also be removed when the tenant brings the account current. Applying and removing over-locks is time-consuming and costly because it includes the manager's time to over-lock the unit and unlock the unit along with the costs associated with the over-locks themselves.
[0006] There is also a desire to automate the payment process and allow the customer to pay rent via a remote process. If the customer decides to make a rent payment when the office is closed, perhaps via a web payment or an automated payment machine. If the manager has over-locked the self-storage unit, then the customer cannot gain access to their unit immediately after making the payment. The delay between payment and removal of the over-lock is aggravating to tenants who may then demand immediate attention.
[0007] Many self-storage facilities will also place over-locks on vacant units to prevent these units from being used by non-paying customers. This creates a similar problem for the self-storage owner. The owner must maintain an adequate supply of over-locks for vacant units and managers must be available to remove the over-locks for new tenants when they rent a self-storage unit. Moreover, if a self-storage owner wants to rent a self-storage unit via a remote process, the customer does not have access to the self-storage unit until the vacant unit over-lock has been removed.
[0008] However, in view of the above, there still remains a need for an electronically-controlled self-storage system that provides facility managers and owners with capabilities that are not possible with the conventional methods.
SUMMARY OF THE INVENTION
[0009] According to its major aspects and briefly described, the present invention is an electronically controlled self-storage over-lock system. Although the system will be described with respect to its application in self-storage facilities, it is clear that the system could be used anywhere an over-lock system is required, such as hotel rooms, apartment buildings, and storage containers and lockers, if permitted by law. Each unit in the facility is preferably equipped with a locking device that is mounted on the inside of the door that can be activated to prevent access to the unit. The locking device controls the movement of the door hasp, which is mounted to the door, and does so preferably electronically, remotely and wirelessly. If the locking device is in the locked position, then the hasp cannot be moved and, accordingly, the door will not open. If the locking device is in the unlocked position, then the hasp can be moved and the door can be opened.
[0010] An administrator manages the electronically controlled over-lock system for use in connection with a self-storage facility. The system comprises: a plurality of self-storage units, each having an electronically activated over-lock; at least one input device (e.g., a card reader, keypad, proximity reader, biometric, display and/or touch screen, etc.) for allowing authorized users, namely tenants and prospective tenants, to communicate with the system; at least one over-lock control unit which is in communication with each electronically-activated over-lock; a computer controlled by the system administrator for maintaining a database of authorized users and the over-lock information for each self-storage unit; a system control device in communication with at least one over-lock control unit and with the computer.
[0011] The authorized user may access the system to verify that the over-lock has been activated, and then make a payment using the input device to deactivate the over-lock. Once the payment is received, the administrator may cause the computer to enter that fact into the database and to signal the system control device to switch the status of the over-lock from activated to deactivated. The system control device generates a signal to the over-lock control unit for that particular tenant's storage unit. The over-lock control unit deactivates the over-lock, thereby permitting the tenant to move the hasp on the door of the storage unit and open the storage unit door.
[0012] A major advantage of the present invention is that the electronically activated over-lock system will reduce the labor requirements for managing a self-storage facility. This advantage derives from the fact that the over-locks can be switched between activated and deactivated conditions without going to each storage unit and manually performing the over-lock process. The system will automatically lock or unlock the over-locked based on the status of the unit and the status of the customer.
[0013] Another major advantage of the present invention is that the self-storage system is able to rent storage units to new tenants and to accept payments from delinquent tenants, and then provide access to storage units at the same time. The electronically activated over-lock will automatically lock or unlock the over-locks based on the status of the unit and the status of the customer without onsite personal.
[0014] These and other features and their advantages will be apparent to those skilled in the art from a careful reading of the Detailed Description of Preferred Embodiments, accompanied by the following drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In the drawings,
[0016] FIG. 1 is a schematic overview of the electronically activated over-lock system according to the preferred embodiment of the present invention.
[0017] FIG. 2 is a schematic overview of the electronically activated over-lock system installed on a self-storage unit, according to the preferred embodiment of the present invention.
[0018] FIG. 3 is a detailed schematic of the electronically activated over-lock system, according to the preferred embodiment of the present invention.
[0019] FIG. 4 is a detailed drawing of the door lock mechanism, according to the preferred embodiment of the present invention.
DESCRIPTION OF THE INVENTION
[0020] The present invention is an over-lock security system. Although the system will be described with respect to its application in self-storage facilities, it is clear that the system could be used anywhere an over-lock system is useful.
[0021] Referring to FIGS. 1 and 2 , each self-storage unit 10 is equipped with an over-lock 100 that is preferably mounted on the inside of self-storage unit 10 , as seen best in FIG. 2 , but, using a wireless connection, over-lock 100 may be mounted on the outside of unit door 700 . Each over-lock 100 can have optional equipment including a lock status indicator 200 and an over-lock indicator 300 . Each over-lock 100 can be switched remotely and wirelessly via an over-lock control unit 400 between opened (unlocked) or closed (locked) positions, based on the current status of the unit and customer, which status is available to a controller 600 having access to a computer database 500 . Communication between the over-lock 100 and the over-lock control unit 400 can be accomplished via wiring or wireless medium with wireless communication preferred. If a person attempts to forcibly open self-storage unit 10 and over-lock 100 contains lock status indicator 200 , then a signal is generated by indicator 200 indicating that a forcible entry has been made. Over-lock indicator 300 displays the current status of unit 10 . Specifically, it may contain a panel that employs light emitting diodes (LEDs) to indicate that door 700 to unit 10 is open, closed, locked or unlocked.
[0022] As best seen in FIG. 2 , there is shown a schematic overview of the over-lock system installed in self-storage unit 10 . The over-lock device 100 can be mounted on the inside of the self-storage unit. The door hasp 900 is mounted on a self-storage door 700 .
[0023] The door hasp 900 is manufactured to allow for external padlocks to be placed on the exterior of the door. When the door hasp 900 is in the closed position, it will extend through doorframe 800 and through over-lock 100 . Over-lock 100 , based on the signal from over-lock control unit 400 , will unlock or lock door hasp 900 by allowing or not allowing it to be retracted through the door frame 800 , respectively. It is apparent that other methods can be used by over-lock 100 for securing the position of door hasp 900 , such as using a pin to extend through a hole in door hasp 900 .
[0024] Referring to FIG. 3 , there is shown a schematic of over-lock 100 . It consists of an actuator 101 , which could be a motor or solenoid, connected to a linkage 102 . Linkage 102 is connected to a door hasp lock mechanism 103 . Door hasp lock mechanism 103 has a slot 104 dimensioned to allow door hasp 900 to pass through. Hasp 900 has a notch 106 formed therein and aligned with door hasp lock mechanism 103 . When over-lock 100 is in the closed or locked position, door hasp lock mechanism 103 is lowered into notch 106 so that door hasp 900 cannot be removed, and thus prevent the opening of door 700 . When over-lock 100 is in the open or unlocked position, door hasp lock mechanism 103 is disengaged from notch 106 and thus allows door hasp 900 to be moved, and thus allowing the opening of door 700 . Lock status alarm 200 , if provided, uses a magnet 105 to detect the position of door hasp 900 in reference to door hasp lock mechanism 103 . Magnet 105 is used by over-lock control unit 400 to monitor the position of door hasp 900 and to emit an alarm. It will be obvious that other methods to detect the position of door hasp 900 could be used, such as hall-effect sensors. Lock status indicator 300 is mounted on the outside of storage unit 10 and contains indicators such as Light Emitting Diodes (LEDs), lamps or other devices to indicate whether door 700 is open or closed. Lock status indicator 300 interfaces with over-lock control unit 400 to provide real-time status display of over-lock 100 positioning.
[0025] Computer 600 can access database 500 of units, authorized users and their accounts to determine if storage units 10 are rented or not and, if rented, whether the account is delinquent or not. If (1) storage unit 10 is not rented OR (2)(a) storage unit is rented AND (b) the account associated with that unit is delinquent, over-lock 100 is locked, otherwise it is unlocked.
[0026] Computer 600 may be directly connected to the database 500 or may be remotely located and communicate to the database 500 via various methods (wireless, internet, etc.) When a tenant's account becomes delinquent, the computer 600 , will update the database 500 and send a signal to over-lock control unit 400 . Over-lock control unit 400 then engages over-lock 100 preventing door hasp 900 from being moved. Preventing movement of door hasp 900 prevents the tenant from having access to self-storage unit 10 .
[0027] When a tenant makes a payment and brings a delinquent account current, computer 600 , will update database 500 and send a signal to over-lock control unit 400 . Over-lock control unit 400 disengages over-lock 100 allowing door hasp 900 to be moved. Movement of door hasp 900 allows the tenant access to self-storage unit 10 .
[0028] When self-storage unit 10 becomes vacant, computer 600 updates database 600 and simultaneously sends a signal to over-lock control unit 400 . Over-lock control unit 400 then engages over-lock 100 preventing door hasp 900 from being moved and preventing self-storage unit 10 from being accessed. If storage unit 10 is rented to a new tenant then the computer 600 , will update database 500 and sends a signal to over-lock unit 400 , which disengages over-lock 100 and allows door hasp 900 to be moved for access to the self-storage unit.
[0029] It is intended that the scope of the present invention include all modifications that incorporate its principal design features, and that the scope and limitations of the present invention are to be determined by the scope of the appended claims and their equivalents. It also should be understood, therefore, that the inventive concepts herein described are interchangeable and/or they can be used together in still other permutations of the present invention, and that other modifications and substitutions will be apparent to those skilled in the art from the foregoing description of the preferred embodiments without departing from the spirit or scope of the present invention.
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The present invention is an electronically controlled self-storage over-lock system that uses distributed processing to allow management to automatically over-lock tenants' units when their accounts become delinquent or when storage units are not rented. Once the self-storage unit door is locked by the over-lock system, tenants cannot access their units their accounts are brought current. Preferably, the over-lock, when in the locked position, prevents movement of the self-storage unit door hasp.
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BACKGROUND OF THE INVENTION
The present invention relates to ball bearings, and more particularly to ball bearings suitable for high-speed fabrication and assembly and particularly advantageous for use in drawer slides.
Manufacture and assembly of ball bearings typically involves several components and several machining operations. Manufacture of ball bearings for use in inexpensive drawer slides normally necessitates a design decision of whether to sacrifice quality to hold cost down, or alternatively achieve quality at a relatively high price.
One ball bearing structure for use in drawer slides optimizing the balance between cost and quality is illustrated in U.S. Pat. No. 4,243,277, issued Jan. 6, 1981, to Fortuna, and entitled BALL BEARING. This bearing includes a hollow stem having a body defining an inner race, a retention washer mounted on the stem and held in position by swaging the stem, a plurality of balls axially retained between the washer and stem body, and a polymeric outer race member defining an outer race. The outer race member includes three axial diametrical portions with the middle portion being the largest in diameter defining the ball race. Although this structure constituted a noteworthy advance over the prior art, it has subsequently been noted that the bearing suffers two minor drawbacks. First, the ball race is open at both of its opposite sides between the inner race and outer race, permitting dirt and other debris to enter the raceway and foul the bearing. This detracts from the smooth operation of the bearing and also reduces the bearing life. Second, the outer race which is snap-fitted over the balls is capable of bearing only relatively small lateral thrust forces.
SUMMARY OF THE INVENTION
The aforementioned problems are overcome in the present invention. Essentially, a ball bearing is provided which can be relatively inexpensively manufactured and yet provides a high-quality feel and smooth operation. The bearing includes a dirt shield to prevent the ingress of dirt and other debris to the ball raceway. Additionally, the outer race member includes an improved thrust bearing surfce to further enhance the quality feel of the bearing.
More particularly, the ball bearing includes an inner race assembly including a hollow inner race member, a washer swaged onto the inner race member to together define an inner race, a plurality of balls positioned within the inner race, and a polymeric outer race member defining an outer race fitted over the balls. The inner race member includes a curvilinear body flaring radially outwardly, and the outer race includes a lateral thrust bearing shoulder extending inwardly to a point closely proximate the flared body of the inner race member. Consequently, the thrust bearing shoulder and the inner race body cooperate to form a dirt shield greatly reducing the contamination of the ball raceway. Further, the thrust bearing shoulder extends inwardly to a point closely proximate the midpoint of the balls to provide an improved lateral thrust bearing surface.
These and other objects, advantages, and features of the invention will be more readily understood and appreciated by reference to the detailed description of the preferred embodiment and the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of the present ball bearing; and
FIG. 2 is a sectional exploded view of the ball bearing.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A ball bearing constructed in accordance with the preferred embodiment of the invention is illustrated in the drawings and generally designated 10. The bearing includes inner race member 12, thrust washer 14, balls 16, and outer race member 18. Thrust washer 14 is swaged onto inner race member 12 to together define an inner ball race; and outer race member 18 defines the outer ball race. Inner and outer race members 12 and 18 therefore define a ball raceway in which balls 16 are positioned.
Inner race member 12 is a one-piece, stamped member, including shoulder 20, generally cylindrical stem 22 extending in a first direction from the shoulder, and flared body portion 24 extending in an opposite direction from the shoulder. Body 24 includes a curvilinear portion 26 which flares radially outwardly and terminates in peripheral edge 28.
Thrust washer 14 includes central aperture 30 having an internal diameter generally identical to the external diameter of inner race stem 22 prior to swaging. Washer 14 is retained in position abutting shoulder 20 by swaging stem 22 (see FIG. 1). In the preferred embodiment, stem 22 is swaged sufficiently so that washer 14 can withstand a minimum of a twenty-five pound-push-off force. The outer diameter 32 of washer 14 is slightly larger than the diameter of peripheral edge 28 of the inner race member.
Balls 16 are positioned between inner race member 12, thrust washer 14, and outer race member 18 within the ball raceway. A full complement of ten balls 16 is included; and no ball retainer is used. As seen in FIG. 1, peripheral edge 28 of inner race member 12 extends outwardly to a point closely proximate the midpoint of balls 16. The outer diameter 32 of thrust washer 14 extends radially outwardly slightly beyond the midpoint of balls 16.
Outer race member 18 is a polymeric annular member, preferably nylon, molded to have three axially spaced internal diameter portions. The central diameter portion 40 is a concave curvilinear surface defining the outer ball race and is the portion of largest diameter. On a first side of central portion 40 is second axial portion or snap rib 42, which is a curvilinear surface convex inwardly which blends into inner race 40. On the other side of outer race 40 is third axial portion or shoulder 44 which extends radially inwardly to terminate in internal edge 46. Shoulder 44 extends to a position closely proximate peripheral edge 28 of inner member 12, which is also closely proximate the midpoint of balls 16. In the preferred bearing, wherein the diameter of outer race 18 is about 0.9 inch, the clearance between edges 28 and 46 is about 0.012 to 0.023 inch. Shoulder 44 provides curvilinear thrust bearing surface 48 which blends into inner race 40. Opposite thrust bearing surface 48 is beveled surface 50 which tapers from internal edge 46 to bearing side 52 to decrease the area presented by side 52 for lateral engagement with the drawer rail. Chamfers 54 and 56 are provided at both peripheral edges of outer race member 18 to aid in positioning the outer race member within automated assembly machinery.
ASSEMBLY AND OPERATION
Ball bearing 10 is assembled by placing inner race member 12 with body portion 24 positioned downwardly in a nest 60. Outer race 18 is concentrically positioned about and slightly above inner race 12 (see FIG. 2). A full complement of ten balls 16 are loaded into the ball raceway between the inner and outer races. The distance between shoulder 20 and snap-rib 42 when the elements are positioned as illustrated in FIG. 2 is slightly greater than the diameter of balls 16. Consequently, balls 16 load easily into the ball raceway. Thrust washer 14 is slid over stem 22 of inner race 12; and the inner race is raised into proper axial orientation with respect to the outer race 18. As the inner race is raised, thrust washer 14 slides into abutment with shoulder 20; and stem 22 is swaged to retain washer 14 in position.
In operation, this relatively inexpensive bearing provides the high-quality feel of more expensive bearings. In particular, the thrust bearing shoulder 44 provides an increased thrust bearing surface for outer race member 18 to provide a tighter feel to bearing 10. As noted above, shoulder 44 extends to a point closely proximate the midpoints of balls 16 so that the thrust surface 48 extends from the top of the ball to approximately the ball midpoint. Additionally, the thrust shoulder 44 and flared body 24 cooperate to form a dirt shield greatly reducing the ingress of dirt and other contaminants to the ball raceway. The close cooperation of peripheral edges 28 and 46 keeps the raceway relatively clean further insuring the smooth feel and long life of the ball bearing.
The above description is that of a preferred embodiment of the invention. Various changes and alterations can be made without departing from the spirit and broader aspects of the invention as set forth in the appended claims, which are to be interpreted in accordance with the principles of patent law, including the doctrine of equivalents.
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The specification discloses a self-contained ball bearing for use in drawer rails. The bearing includes balls axially retained between a flared end of an inner race member and a washer retained on a stem of the inner race member. The bearing further includes a polymeric outer race member having a thrust shoulder extending radially inwardly closely proximate the flared end of the inner race member to form a dirt shield therewith and to provide an improved thrust bearing surface.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of International Application PCT/EP01/08958 with an international filing date of Aug. 2, 2001, not published in English under PCT Article 21(2), and now abandoned.
BACKGROUND OF INVENTION
[0002] 1. Field of the Invention.
[0003] The invention relates to a fabric belt for a corrugated cardboard gluing machine. The fabric belt comprises a first fabric layer, comprised of warp threads and weft threads, for receiving tensile forces and an additional upper fabric layer covering the first fabric layer and comprised of warp threads and weft threads. The upper fabric layer forms the upper paper side. The fabric layers are interwoven by means of binding threads.
[0004] 2. Description of the Related Art
[0005] WO 96/07788 discloses a woven fabric belt for a corrugated cardboard gluing machine that ensures excellent dewatering of the material placed on top over a long period of operation with a high-quality standard. As a result of growing requirements, it must be ensured that the belt has a sufficiently high mechanical strength. This leads to multi-layer fabric structures that reduce the permeability of the belt in a disadvantageous way.
SUMMARY OF INVENTION
[0006] It is an object of the present invention to configure a belt for a corrugated cardboard gluing machines such that, despite its multi-layer structure and high mechanical strength, a high permeability of the belt for fast dessication of the material placed on top is achieved.
[0007] In accordance with the present invention, this is achieved in that the belt has drainage channels penetrating the belt at least partially. Vis the drainage channels, vapor or moisture can be removed from the upper fabric layer and from the paper side.
[0008] By means of the drainage channels, the vapor (moisture) is removed from the paper side to the opposite side of the belt.
[0009] The drainage channels can be formed as openings in the woven structure of the fabric. However, it can also be expedient to from the drainage channels by providing different thread thicknesses and/or thread structures. The drainage channels can be formed by the thread gaps that are formed by omitting or adding threads.
[0010] In particular, the drainage channels can be formed by individual threads of a fabric layer, wherein the individual treads are comprised of a material that forms cavities after a short period of time.
[0011] Such cavity-forming thread material is configured such that for the technical weaving process it can be processed like a conventional single thread and serves within the fabric structure as a three-dimensional spacer element. After a certain operating time of the belt, for example, after the conventional break-in time of the belt, the thread material has formed a cavity that acts within the woven fabric structure as a drainage channel.
[0012] The cavity-forming thread material can be a thread material having a high proportion of starch; preferably, the cavity-forming threads are comprised completely of starch. Thread material of starch can be processed in the dry state like a conventional thread. However, as soon as such a cavity-forming thread comprised of starch comes into contact with water, the starch will dissolve and will be washed out with the water. The material of the cavity-forming thread is thus dissolved away from the woven fabric structure so that a gap is formed that extends as a drainage channel across the length and/or width and/or height of the belt.
[0013] Expediently, the cavity-forming thread material can also be a thread material comprised of cavity-containing (hollow) fibers that have only minimal wear resistance. After the break-in time of the belt, the cavity-containing fibers will be worn and break open so that the cavity, now open to the exterior, forms a drainage channel. Such hollow fibers or cavity-containing fibers employ in addition capillary action for removal of liquids from the face of the paperPreferably, the drainage channels open at the underside of the belt. In a particular configuration, the drainage channels are configured as cavities penetrating the belt. The configuration of the fabric structure provided during weaving allows for providing a constructively precise position of the drainage channels and a desired number of drainage channels per unit of surface area.
[0014] Advantageously, the belt is made of plastic material threads comprised of a mixture of approximately 65% polyester and approximately 35% viscose.
[0015] Expediently, thread material that has a high temperature resistance, in particular, material in the form of para aramids or Kevlar® (registered trademark of the DuPont Corp.), is woven into the belt; this thread material provides at the same time wear protection. In particular, the temperature-resistant thread material is woven into the belt within a narrow area along the longitudinal edges, i.e., in the direction of the warp threads. However, it can be advantageous to weave the temperature-resistant thread material, in particular, in the form of warp threads, into the upper and/or lower fabric layer within a wide edge area up to the point of completely covering the surface area.
BRIEF DESCRIPTION OF DRAWINGS
[0016] [0016]FIG. 1 shows a first embodiment of a woven belt according to the present invention in longitudinal section.
[0017] [0017]FIG. 2 shows a partial plan view onto the upper fabric layer forming the side facing the paper (paper side) of the belt of FIG. 1.
[0018] [0018]FIG. 3 is a plan view onto the exterior side of the lower fabric layer of the belt of FIG. 1.
[0019] [0019]FIG. 4 is a schematic plan view onto the paper side of the belt according to FIG. 1.
[0020] [0020]FIG. 5 is a schematic illustration of a second embodiment of a woven belt according to the present invention in longitudinal section.
[0021] [0021]FIG. 6 is a schematic illustration of a plan view onto the upper fabric layer of the belt of FIG. 5, wherein the upper fabric layer forms the paper side.
[0022] [0022]FIG. 7 is a schematic illustration of a plan view onto the lower fabric layer of the belt of FIG. 5.
[0023] [0023]FIG. 8 is a schematic illustration of a third embodiment of a woven belt according to the present invention in longitudinal section.
[0024] [0024]FIG. 9 is a schematic illustration of a plan view of the upper fabric layer of the belt of FIG. 8 forming the paper side.
[0025] [0025]FIG. 10 is a schematic illustration of a plan view onto the lower fabric layer of the belt of FIG. 8.
DETAILED DESCRIPTION
[0026] [0026]FIG. 1 shows a first embodiment of a belt 1 according to the present invention. The belt 1 that is preferably manufactured of plastic (synthetic) material threads is comprised of an upper fabric layer 10 , a central or middle fabric layer 20 for receiving or absorbing tensile forces, and a lower fabric layer 30 . The side of the upper fabric layer 10 facing away from the fabric layer 20 that is arranged centrally and absorbs the tensile forces forms the paper side (side facing the paper) of the fabric belts 1 .
[0027] In the fabric layers 10 , 20 , 30 the weft threads 4 extend transversely to the longitudinal direction 5 (FIG. 2) of the belt 1 .
[0028] In the upper or top fabric layer 10 a repeating set of four warp threads 11 , 12 , 13 , and 14 (FIGS. 1 and 2) are provided; they extend displaced or staggered relative to one another. These warp threads cross, inwardly toward the central fabric layer 20 as well as outwardly toward the paper side, at least two weft threads 4 (FIG. 1), respectively.
[0029] The central fabric layer 20 receiving the tensile forces has two warp threads 21 , 22 that are displaced or staggered relative to one another and cross two weft threads 4 , respectively.
[0030] The lower fabric layer 30 is comprised of four warp threads 31 , 32 , 33 , 34 that are displaced or staggered relative to one another and cross inwardly, toward the central fabric layer 20 , only a single weft thread 4 and outwardly at least three weft threads 4 .
[0031] The three fabric layers 10 , 20 , 30 are interwoven with one another by means of binding threads 40 , 41 , 42 , 43 . The binding threads are divided into two thread groups. The binding fibers 42 , 43 form a first thread group and are displaced relative to one another; they connect the upper fabric layer 10 and the central fabric layer 20 to one another. The binding threads 42 , 43 are alternatingly guided across one warp thread 4 in the upper fabric layer 10 and one warp thread 4 in the lower fabric layer 20 . Similarly, a second thread group is formed of the binding threads 40 and 41 , and the threads 40 , 41 connect the lower fabric layer 32 and the central fabric layer 20 .
[0032] As illustrated in FIG. 4 in connection with FIGS. 1 to 3 , in the illustrated embodiment at least one warp thread 14 ′ extending in the longitudinal direction 5 of the belt 1 is provided in the upper fabric layer 10 of the belt 1 ; the thread 14 ′ is comprised of a cavity-forming thread material, i.e., a thread material that is different from the warp threads 11 , 12 , 13 and 14 provided across the remaining portion of the upper fabric layer 10 . The individual warp threads 11 ′, 12 ′, 13 ′, 14 ′ of the paper-forming fabric layer 10 are comprised of cavity-forming thread material that communicates with drainage channels 500 . Each drainage channel 500 is preferably provided as a cavity that is mechanically woven into the fabric and extends from the paper side away in the direction toward the underside of the belt. Preferably, the cavity 500 opens at the underside of the belt that is facing away from the paper side and is formed in particular as a cavity penetrating the belt. In this way, as illustrated in FIG. 4, the cavities 500 are designed like a drain through which vapor or moisture can be guided away from the paper side of the upper fabric layer 10 through the belt 1 .
[0033] The weft threads 4 ′ and the warp threads 11 ′, 12 ′, 13 ′, 14 ′ advantageously cross the drainage channels 500 that are mechanically woven into the belt 1 . In particular, the drainage channels 500 are arranged at the crossing points of the weft threads 4 ′ and the warp threads 11 ′, 12 ′, 13 ′, 14 ′.
[0034] The cavity-forming thread material is, for example, a thread material having a high starch content. Preferably, the thread material is comprised completely of starch. This has the result that, in the dry state, the cavity-forming threads consisting of starch or containing a high percentage of starch can be processed like regular threads. In the fabric structure, they form stand-ins that dissolve upon contact with liquid, in particular, water. The voids that result after dissolution and washing out of the starch within the fabric provide drainage channels, drainage grooves or the like that open into the drainage channels 500 mechanically woven into the material. In this way, in the area between the drainage channels 500 a kind of drainage grid is formed which supplies the liquid that is present directly to the mechanically woven drainage channel 500 and in this way ensures a quick dewatering action of the material placed onto the fabric belt. In this connection, the warp threads made of cavity-forming thread material, after a certain operating time has elapsed, form longitudinal channels in the longitudinal direction and weft threads 4 ′ made of such a cavity-forming thread material form transverse channels. Since the longitudinal channels and the transverse channels cross one another because of the fabric structure (warp threads, weft threads), the transverse channels and the longitudinal channels are connected to one another in order to provide flow communication. A fast drainage of the liquid is provided in this way.
[0035] The cavity-forming thread material can also be in the form of hollow fibers (cavity-containing fibers). After elapse of a certain operating time, as a result of wear that occurs on the belt, the hollow fibers will open so that their inner cavities themselves will form drainage channels that extend in the longitudinal direction of the warp and weft threads.
[0036] In order to continue the drainage structure in the direction of depth, there are also warp and weft threads of cavity-forming thread material provided in the additional fabric layers 20 and 30 . It is also possible to provide individual binding threads that are made of cavity-forming thread material so that drainage channels can be formed in the fabric structure that extend from one fabric layer 10 , 20 to another fabric layer 20 , 30 .
[0037] It can be expedient for the purpose of preventing a disturbance of the woven structure to provide a cavity-forming thread material as an auxiliary thread 4 ″ added to a warp thread, a weft thread, or a binding thread. The number of warp threads, weft threads, and binding threads that determine the fabric structure remains unchanged; a thread made of cavity-forming thread material is added as an auxiliary thread 4 ″ to a warp thread and/or a weft thread and/or a binding thread and, as a stand-in, forms later on the desired drainage channels.
[0038] Cavity-forming threads can be expediently provided in the fabric layer 10 forming the paper side, wherein, for enhancing the dewatering action and for forming the drainage channels 500 , the other fabric layers 20 , 30 can also contain cavity-forming threads.
[0039] [0039]FIG. 5 shows a schematic illustration of a second fabric belt 2 in longitudinal section. The belt 2 is comprised of an upper fabric layer 50 and a lower fabric layer 60 . The upper fabric layer 50 forming the paper side has a repeating set of four warp threads 51 , 52 , 53 , and 54 that are displaced (staggered) relative to one another, and the lower fabric layer 60 has a repeating set of four warp threads 61 , 62 , 63 , and 64 that are displaced or staggered relative to one another. The weft threads 6 extend transversely to the longitudinal direction 7 . The warp threads cross two weft threads 6 , respectively. The upper fabric layer 50 and the lower fabric layer 60 are connected to one another by binding threads 44 , 45 wherein the binding threads are displaced or staggered relative to one another and cross one weft thread 6 , respectively.
[0040] [0040]FIG. 6 shows a schematic illustration of a plan view onto the upper fabric layer, and FIG. 7 a schematic illustration of a plan view onto the lower fabric layer of the same belt section illustrated in FIG. 6. The four warp threads 51 , 52 , 53 and 54 are arranged adjacent to one another and two binding threads 44 and 45 are arranged adjacent to them. The threads of the lower fabric layer 60 , as illustrated in FIG. 7, are woven correspondingly. The warp thread 52 of the upper fabric layer 50 and the warp threads 62 and 64 of the lower fabric layer 60 have a greater diameter than the other warp threads. In this way, drainage channels are formed wherein the upper fabric layer 50 has more drainage channels than the lower fabric layer 60 . The drainage channels can also be formed by the thread structure of the warp threads 51 through 54 and 61 through 64 . For this purpose, the threads can have, for example, grooves in the longitudinal direction.
[0041] [0041]FIGS. 8, 9, and 10 show a belt 3 comprising an upper fabric layer 70 and a lower fabric layer 80 . The warp threads 71 to 74 of the upper fabric layers 70 and the warp threads 81 and 84 of the lower fabric layer 80 extend in accordance with the warp threads 51 to 54 and 61 to 64 in FIG. 5. The upper fabric layer 70 and the lower fabric layer 80 are interwoven with one another by binding threads 46 and 47 wherein the binding threads 46 , 47 cross one weft thread 8 of the fabric layers 70 and 80 , respectively. FIG. 9 shows a schematic plan view of the belt 3 . The warp threads 71 to 74 are woven adjacent to one another; adjacently arranged are the binding threads 46 and 47 . The drainage channels 500 are formed by omitting every other warp thread set of the fabric layer 70 so that, from top to bottom as illustrated in FIG. 9, a second arrangement of binding threads 46 and 47 follows the arrangement of the upper binding threads 46 and 47 ; a repeating set of warp threads 71 to 74 then follows the lower arrangement of binding threads 46 , 47 . The lower fabric layer 80 illustrated in FIG. 10 in a view onto the bottom side of the belt 3 extends in accordance with the lower fabric layer 60 of the belt 2 illustrated in FIG. 7, wherein the warp threads 81 to 84 of the lower fabric layer 80 can all have the same diameter.
[0042] For increasing the temperature resistance and wear resistance of belts 1 , 2 , 3 , thread material having a high temperature resistance, in particular, para aramids or Kevlar®, can be woven into the edge area of the belt in the longitudinal direction 5 , 7 of the belt. However, the temperature resistant thread material can also extend across the entire width of the upper fabric layer 10 , 50 , 70 or the lower fabric layer of 30 , 60 , 80 or the upper and lower fabric layers. The drainage channels 500 can also be formed as openings in the woven structure. For this purpose, neighboring warp threads of a fabric layer can cross one another, for example.
[0043] The thread material can be comprised of 65% polyester and 35% viscose. Other combinations or compositions can also be advantageous.
[0044] The thread material can also be a monofilament.
[0045] While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.
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A fabric belt for a corrugated cardboard gluing machine has a first fabric layer for receiving tensile forces. The first fabric layer is made of warp threads and weft threads. A second fabric layer covers the first fabric layer and is made of warp threads and weft threads. The second fabric layer forms an upper paper side of the fabric belt. The first and second fabric layers are interwoven by binding threads. The fabric belt has drainage channels penetrating the fabric belt at least partially, wherein the drainage channels remove moisture from the second fabric layer and the upper paper side.
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BACKGROUND OF THE INVENTION
[0001] The present invention relates to a sewing machine frame made from a synthetic resin in which an arm portion, a tower portion and a bed portion are provided integrally. The present invention also relates to a sewing machine having the sewing machine frame.
[0002] In the sewing machine frame, a horizontally extending arm portion supports a reciprocation mechanism for a needle carrying a needle thread, and the tower portion vertically extends from the bed portion for supporting the arm portion in a cantilevered fashion. In the bed portion, a loop taker is supported for trapping a loop of the needle thread carried on the vertically reciprocating needle in order to form a stitch.
[0003] In the sewing machine, a smooth stitching operation is required. To this effect, vibration and displacement of a needle tip due to the vertically reciprocating motion of the needle must be reduced or minimized, otherwise a loop seizing beak of the loop taker disposed in the bed portion cannot trap the needle thread loop formed by vertical reciprocation of the sewing needle. Thus, the stitching may be degraded.
[0004] In order to avoid this problem, the needle & rotary hook timing must be adequately provided. To this effect, the sewing machine frame must provide high rigidity capable of avoiding deformation or displacement thereof due to reaction force occurring when the needle penetrates a workpice fabric. Therefore, in the conventional sewing machine, a metallic frame having high rigidity is provided in an interior of a sewing machine cover, and a stitch forming mechanism including a needle vertical reciprocating mechanism and the loop taker is attached to the metallic frame.
[0005] However, such a conventional arrangement is costly, bulky and heavy. More specifically, the sewing machine frame has a rigid box shape arrangement in order to provide high rigidity. Further, the frame is made from a metal such as a cast iron or aluminum, which in turn increase weight and size. Further, high skill and elaboration is required for assembling the sewing machine because the stitch forming mechanism must be installed into the metallic frame through a small area opening thereof. This increases assembly cost.
[0006] Laid open Japanese Patent Application Kokai No.Hei-11-137880 discloses a sewing machine frame made from a synthetic resin to reduce production cost and to provide a light weight frame. As shown in FIG. 16, the frame 300 has an open end arrangement in a U-shape cross-section in which a bed portion 304 , a tower portion 303 and an arm portion 302 are provided integrally, and a reinforcing plate 301 is fixed between upper and lower portions at the open end of the bed portion 304 .
[0007] However, the disclosed sewing machine frame 300 provides a rigidity still lesser than that of the metallic frame. More specifically, as shown in FIG. 16, vertical vibration occurs in the arm portion 302 due to a load exerted along a vertical line containing the needle, the load being caused by the reciprocating motion of the needle during stitching operation. Further, a horizontal swing also occurs at an upper portion of the tower portion 303 during stitching. The horizontal swing may be generated by distortion of the tower portion 303 and the bed portion 304 due to the distortion of the arm portion 302 caused by the vertical reciprocation of the sewing needle.
[0008] Accordingly, the disclosed sewing machine frame 300 is still insufficient in terms of rigidity, to lower stitching quality in comparison with the conventional sewing machine provided with the metallic frame.
SUMMARY OF THE INVENTION
[0009] It is an object of the present invention to overcome the above-described problems and to provide a sewing machine frame having a bed portion, a tower portion and an arm portion those integrally with each other and formed of a synthetic resin, yet having high rigidity, and to provide a sewing machine having such an improved sewing machine frame.
[0010] This and other objects of the present invention will be attained by a sewing machine frame for a sewing machine including an integral frame member, and reinforcing ribs. The integral frame member is made from a synthetic resin and provides an outer surface defining an external shape and an inner surface providing an internal space. The integral frame member includes a bed portion, a tower portion upstanding from the bed portion, and an arm portion extending from the tower portion in a cantilevered fashion. The reinforcing ribs are provided at substantially entire area of the inner surface for reinforcing the integral frame member.
[0011] In another aspect of the invention, there is provided a sewing machine frame for a sewing machine, the sewing machine including a vertical reciprocation mechanism for a needle carrying a needle thread, and a loop taker trapping a loop of the needle thread carried on the reciprocating needle to form a stitch. The frame includes an integral frame member, and reinforcing ribs. The integral frame member is made from a synthetic resin and provides an outer surface defining an external shape and an inner surface providing an internal space. The integral frame includes a bed portion for supporting the loop taker in the internal space, a tower portion upstanding from the bed portion, and an arm portion extending from the tower portion in a cantilevered fashion for supporting the vertical reciprocation mechanism in the internal space. The reinforcing ribs are provided at substantially entire area of the inner surface.
[0012] In still another aspect of the invention, there is provided a sewing machine including a stitch forming mechanism and any one of the above-described sewing machine frame.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The aforementioned aspects and other features of the invention are explained in the following description, taken in connection with the accompanying drawing figures wherein:
[0014] [0014]FIG. 1 is a front view showing the overall construction of a sewing machine comprising a frame according to the preferred embodiment;
[0015] [0015]FIG. 2 is a side view showing the overall construction of the sewing machine in FIG. 1;
[0016] [0016]FIG. 3 is a perspective view showing the external appearance of a main frame;
[0017] [0017]FIG. 4 is a perspective view showing the internal construction of the main frame;
[0018] [0018]FIG. 5 is a plan view showing the internal construction of the main frame;
[0019] [0019]FIG. 6(A) is a cross-sectional view along the plane of the main frame indicated by the arrows A in FIG. 5;
[0020] [0020]FIG. 6(B) is a cross-sectional view along the plane of the main frame indicated by the arrows B in FIG. 5;
[0021] [0021]FIG. 7(A) is a cross-sectional view along the plane of the main frame indicated by the arrows C in FIG. 5;
[0022] [0022]FIG. 7(B) is an enlarged view showing the lower end of the main frame;
[0023] [0023]FIG. 7(C) is a cross-sectional view along the plane of the main frame indicated by the arrows D in FIG. 5;
[0024] [0024]FIG. 8(A) is a cross-sectional view along the plane of the main frame indicated by the arrows E in FIG. 5;
[0025] [0025]FIG. 8(B) is a cross-sectional view along the plane of the main frame indicated by the arrows F in FIG. 5;
[0026] [0026]FIG. 8(C) is an enlarge view of a protrusion;
[0027] [0027]FIG. 8(D) is a cross-sectional view along the plane of the main frame indicated by the arrows M in FIG. 5;
[0028] [0028]FIG. 9(A) is an enlarged plan view showing the main frame from the perspective of the line G in FIG. 5;
[0029] [0029]FIG. 9(B) is an enlarged plan view showing the main frame from the perspective of the line H in FIG. 5;
[0030] [0030]FIG. 10 is a perspective view showing the external appearance of the frame cover;
[0031] [0031]FIG. 11 is a perspective view showing the internal construction of the frame cover;
[0032] [0032]FIG. 12 is a plan view showing the internal construction of the frame cover;
[0033] [0033]FIG. 13 is a cross-sectional view along the plane of the frame cover indicated by the arrows I in FIG. 12;
[0034] [0034]FIG. 14(A) is a cross-sectional view along the plane of the frame cover indicated by the arrows J in FIG. 12;
[0035] [0035]FIG. 14(B) is an enlarged view showing the lower end of the frame cover;
[0036] [0036]FIG. 15(A) is an enlarged plan view along the plane of the frame cover indicated by the arrows K in FIG. 12;
[0037] [0037]FIG. 15(B) is an enlarged plan view along the plane of the frame cover indicated by the arrows L in FIG. 12; and
[0038] [0038]FIG. 16 is a perspective view showing a conventional sewing machine frame.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0039] Structure of a Sewing Machine
[0040] A sewing machine frame according to a preferred embodiment of the present invention will be described while referring to the accompanying drawings. First the overall construction of a sewing machine comprising a frame according to the preferred embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a front view, and FIG. 2 is a side view showing the overall construction of the sewing machine comprising a frame 1 according to the preferred embodiment.
[0041] As shown in FIG. 1, the frame 1 substantially comprises a bed 8 , a cantilever support 7 provided vertically on the bed B, an arm 6 , and an arm 6 cantilevered from the cantilever support 7 above the bed 8 . The bed 8 , the cantilever support 7 , and the arm 6 are integrally formed of a synthetic resin in a substantially C shape.
[0042] The frame 1 supports a stitch forming mechanism including a loop taker and a mechanism for driving a needle 16 reciprocally up and down, and constitutes a shell of the sewing machine. In other words, the frame 1 does not need any metallic frame for mounting the stitch forming mechanism. Accordingly, it is possible to manufacture a lighter frame 1 having simplified structure, compared with a conventional metal frame to mount a stitch forming mechanism, covering with a resin cover. The frame 1 may be formed of a synthetic resin material by using a well-known injection molding method.
[0043] The synthetic resin material for the frame 1 may be a noncrystalline thermoplastic resin, such as a styrene resin. More specifically, the material may be one or mixture of acrylonitrile-butadiene-styrene copolymer, polystyrene, acrylonitrile-styrene, acrylonitrile-acrylate-styrene, acrylonitrile-ethylene-styrene, chlorinated acrylonitrile-polyethylene-styrene. Of these materials, a resinous matter having acrylonitrile-butadiene-styrene copolymer as the primary component with an inorganic additive of talc or glass bead has good rigidity and a good thermal expansion coefficient. The usage of the above material may eliminate frame coating in the later step due to a good appearance of the frame.
[0044] The arm 6 supports a top mechanism 3 for reciprocally driving the needle 16 up and down, the needle 16 retaining needle thread. A motor 2 provided in the cantilever support 7 generates rotational motion. The top mechanism 3 converts this rotational motion to reciprocal motion by means of a crank mechanism to transfer the reciprocal motion to the needle 16 . The top mechanism 3 comprises a spindle 12 , a thread take-up crank 13 , a needle bar holder 14 , a needle bar 15 , and a thread take-up lever link hinge pin 17 mounted in a metal top frame 11 . The top frame 11 is directly attached to the frame 1 by several screws.
[0045] Next, the operations of the top mechanism 3 will be described. A rotational driving force generated by the motor 2 is transferred to a large pulley 35 via a motor belt 36 . The rotational driving force transferred to the large pulley 35 is further transferred to the thread take-up crank 13 via an arm shaft 31 and the spindle 12 . The arm shaft 31 is rotatably supported by two bearings 32 , 32 . The spindle 12 is linked to the arm shaft 31 via a coupler. Through the movement of a needle bar crank rod, rotational motion transferred to the thread take-up crank 13 is converted to reciprocal motion of the needle bar 15 that is supported rotatably on the needle bar holder 14 . The needle bar 15 is capable of moving vertically in the needle bar holder 14 . This reciprocal motion is transferred to the needle 16 .
[0046] The arm 6 is supported on the top end of the cantilever support 7 , while the bed 8 is connected to the bottom end of the cantilever support 7 . A drive transferring mechanism 5 is disposed in the cantilever support 7 for transferring rotational driving force generated by the motor 2 to the top mechanism 3 housed in the arm 6 and a lower mechanism 4 housed in the bed 8 . The drive transferring mechanism 5 comprises the motor 2 , the large pulley 35 , the motor belt 36 , a pulley 38 , a pulley 39 , and a timing belt. The drive transferring mechanism 5 is directly attached to the frame 1 . The motor 2 is supported by motor supporting brackets 33 that are fixed near the bottom end of the cantilever support 7 .
[0047] Next, the operations of the drive transferring mechanism 5 will be described. The rotational driving force provided by the motor 2 is transferred to the large pulley 35 via the motor belt 36 . The rotational driving force transferred to the large pulley 35 is then transferred to the arm shaft 31 rotatably supported by the two bearings 32 , 32 . As described above, this rotational motion is transferred to the top mechanism 3 via the spindle 12 , while this movement is also transferred to the lower mechanism 4 . That is, the pulley 39 is fixed at approximately the center point of the arm shaft 31 . Rotational motion transferred to the pulley 39 is further transferred to the pulley 38 disposed in the bed 8 via the timing belt 41 . A rotary hook shaft 37 is rotatably supported by a bearing 32 . Since the rotary hook shaft 37 is linked to the pulley 38 , the rotary hook shaft 37 rotates in synchronization with the rotations of the arm shaft 31 due to the rotational motion of the pulley 38 .
[0048] The cantilever support 7 is formed on one end of the bed 8 . The bed 8 supports a rotary hook 23 constituting a loop taker for catching a thread loop of the needle thread as the needle moves up and down and forming a stitch. The lower mechanism 4 is provided inside the bed 8 for rotating the rotary hook 23 in synchonization with the reciprocal motion of the needle 16 . The lower mechanism 4 comprises a rotary hook shaft 21 , a helical gear 22 , the rotary hook 23 , a helical gear 24 , and the rotary hook shaft 37 mounted on a metal lower frame 20 . The lower frame 20 is mounted directly on the frame 1 by a plurality of screws.
[0049] Next, the operations of the lower mechanism 4 will be described. The rotational motion transferred via the timing belt 41 to the pulley 38 is transferred to the helical gear 22 via the rotary hook shaft 37 rotatably supported by the bearing 32 and the rotary hook shaft 21 rotatably supported by two bearings 25 , 25 and linked to the rotary hook shaft 37 via a coupler. As shown in FIG. 2, the helical gear 22 is fixed on the rotary hook shaft 21 . A rotary hook shaft on which the rotary hook 23 is fixed is rotatably supported on the lower frame 20 for rotating beneath the top surface of the bed 8 . The helical gear 24 engaged with the helical gear 22 is fixed to the rotary hook shaft. Accordingly, when the rotary hook shaft 21 rotates, the rotary hook 23 rotates via the helical gear 22 and helical gear 24 . At the same time, A loop seizing beak of the loop taker moves in synchronization with the tip of the needle 16 , and catches the thread loop of the needle thread supported on the needle 16 as the needle 16 moves vertically.
[0050] Sewing Machine Frame
[0051] In order to execute smooth sewing operations with a sewing machine having the construction described above, it is necessary to minimize vibration caused by the vertical movement of the needle 16 . Simultaneously, displacement of the needle tip caused by deformation of the frame 1 due to the vertical movement of the needle 16 is required to be minimized. This is because large amount of the displacement and the vibration of the needle tip can prevent the loop seizing beak of the loop taker provided in the bed 8 from catching the thread loop, resulting in the formation of an inappropriate stitch. To avoid this, it is necessary to maintain at all times an appropriate needle and rotary hook timing between the loop seizing beak of the rotating rotary hook 23 and the needle 16 that is moved reciprocally up and down. Accordingly, the frame 1 must have high rigidity in order to prevent deformation (displacement) due to a reaction force generated when the needle penetrates a working piece cloth. However, since it is difficult to maintain sufficient rigidity in a frame formed of synthetic resin, the frame 1 of the present embodiment employs various constructions to achieve sufficient rigidity.
[0052] As shown in FIG. 2, the frame 1 is formed of a main frame 1 A and a frame cover 1 B along a dividing plane 52 formed in approximately the center of the periphery of the frame 1 when viewed from the end (the dotted line in FIG. 2). The main frame 1 A is provided with the stitch forming mechanism including the top mechanism 3 for driving the needle 16 reciprocally up and down and the lower mechanism 4 for rotating the rotary hook 23 . The frame cover 1 B is coupled to the main frame 1 A to cover the stitch forming mechanism.
[0053] The insides of the main frame 1 A and frame cover 1 B are configured to accommodate the top mechanism 3 and the lower mechanism, as shown when the main frame 1 A and frame cover 1 B are in an open state divided along the dividing plane 52 (refer to FIGS. 4 and 11). when assembling the sewing machine, the top mechanism 3 and the lower mechanism are first mounted in the main frame 1 A while the main frame 1 A is rendered in an open state. The main frame 1 A and frame cover 1 B are then joined together by inserting screws through couplings 90 , 190 provided in the main frame 1 A and the frame cover 1 B (see FIGS. 4 and 11). By simplifying the process for assembling the sewing machine in this way, it is possible to reduce the assembly costs. Since the open area of the frame is closed after assembly, the frame retains sufficient rigidity, and the arm 2 is not easily subject to torsional deformation due to reciprocal motion of the needle 16 .
[0054] Main Frame
[0055] Next, the main frame 1 A of the frame 1 will be described with reference to FIGS. 3 through 9. FIG. 3 is a perspective view showing the external appearance of the main frame 1 A. FIG. 4 is a perspective view showing the internal construction of the main frame 1 A FIG. 5 is a plan view showing the internal construction of the main frame 1 A. FIG. 6(A) is a cross-sectional view along the plane of the main frame 1 A indicated by the arrows A in FIG. 5. FIG. 6(B) is a cross-sectional view along the plane of the main frame 1 A indicated by the arrows B in FIG. 5. FIG. 7(A) is a cross-sectional view along the plane of the main frame 1 A indicated by the arrows C in FIG. 5. FIG. 7(B) is an enlarged view showing the lower end of the main frame 1 A. FIG. 7(C) is a cross-sectional view along the plane of the main frame 1 A indicated by the arrows D in FIG. 5. FIG. 8(A) is a cross-sectional view along the plane of the main frame 1 A indicated by the arrows E in FIG. 5. FIG. 8(B) is a cross-sectional view along the plane of the main frame 1 A indicated by the arrows F in FIG. 5. FIG. 8(C) is an enlarge view of a protrusion shown in FIG. 8(B). FIG. 8(D) is a cross sectional view along the plane of the main frame 1 A indicated by the arrows M. FIG. 9(A) is an enlarged plan view showing the main frame 1 A from the perspective of the line G in FIG. 5. FIG. 9(B) is an enlarged plan view showing the main frame 1 A from the perspective of the line H in FIG. 5.
[0056] As shown in FIG. 3, the main frame 1 A substantially comprises the arm 6 , the cantilever support 7 , and the bed 8 formed integrally. The semicircular space surrounded by the arm 6 , cantilever support 7 , and bed 8 is a space 9 .
[0057] In addition, the main frame 1 A comprises a back panel wall 250 constituting a back side of the sewing machine, and side wall 251 extending from a peripheral edge 250 a of the back panel wall 250 . Especially, the surface of the main frame 1 A facing the space 9 is designated as an inner surface wall 51 . The inner surface wall 51 has a rectangular opening 53 that a cloth-pressing lever for fabric (not shown) is passed through.
[0058] As shown in FIGS. 1, 4 and 5 , the main frame 1 A is provided with an arrangement for mounting stitch forming mechanism. More specifically, the interior of the arm 6 is provided with a pair of thread take-up shaft supports 140 , 140 for rotatably supporting the thread take-up lever link hinge pin (not shown); a needle bar holder mount 141 on which the needle bar holder 14 is mounted; an upper frame mount 142 on which the top frame 11 is mounted; and a pair of arm shaft supports 144 , 144 for rotatably supporting the arm shaft 31 that transfers the rotational drive force from the motor 2 to the top mechanism 3 . Motor support bracket mounts 146 are mounted in the cantilever support 7 for attaching the motor supporting brackets 33 that fixedly support the motor 2 . Further, the interior of the bed 8 is provided with a pair of lower conducting shaft supports 147 , 147 for rotatably supporting the rotary hook shaft 37 that transfer the rotational drive force from the motor 2 to the lower mechanism 4 , and a lower frame mount 148 on which the lower frame 20 is mounted.
[0059] Reinforcing Member
[0060] Referring to FIGS. 4 and 5, a reinforcing member 60 is provided around the inner surface wall 51 of the main frame 1 A facing the space 9 surrounded by the arm 6 , cantilever support 7 , and bed 8 . The reinforcing member 60 is formed integrally with the back panel wall 250 . One end of the reinforcing member 60 extends along the longitudinal direction of the arm 6 to the point adjacent to the side wall 251 at one end of the arm 6 opposing the cantilever support 7 . The other end of the reinforcing member 60 extends along the longitudinal direction of the bed 8 to the point adjacent to the side wall 251 at one end of the bed 8 opposing the bed 8 . As described above, the reinforcing member 60 comprises three parts: one part placed around the inner surface wall 51 in a semicircle shape, another part placed in a linear manner as if it crosses the arm 6 , and the other part placed in a linear manner as if it crosses the bed 8 . Accordingly, the reinforcing member 60 is placed in a continuous manner to form a U-shape as a whole. The above structure of the reinforcing member 60 reinforces projecting portions of the arm 6 and the bed 8 which extend from the cantilever support 7 .
[0061] Referring to FIG. 8(D), the reinforcing member 60 has a tubular shape with a hollow circular cross-section. This reinforcing member 60 is formed with the back panel wall 250 integrally to project from the inner surface of the back panel wall 250 . The reinforcing member 60 is formed in a tubular shape for the following reasons. As described above, the main frame 1 A is formed according to an injection molding method. In this method, after injecting a molten resinous material in a cavity die shell, the resinous material is cooled. At this time, thicker portions of the molded product harden slower than thinner portions. Since contraction is greater at the thicker portions, shrinkage occurs in those portions. In order to prevent such shrinkage, it is necessary to maintain a uniform thickness in the molded product. For this reason, the reinforcing member 60 is formed in a hollow tubular shape. When forming the frame 1 , the tubular shape of the reinforcing member 60 is formed by injecting an inert fluid, such as argon gas or nitrogen gas, through an injection hole 61 formed at one end of the reinforcing member 60 adjacent to the side wall 251 , and subsequently cooling the reinforcing member 60 .
[0062] The above structure of the reinforcing member 60 ensures the rigidity of the inner surface wall 51 facing the space 9 surrounded by the arm 6 , the cantilever support 7 , and the bed 8 on which stress caused by the reciprocating motion of the needle 16 is concentrated. The above structure of the reinforcing member 60 also ensures the rigidity of the back panel wall 250 and the side wall 251 of the arm 6 , cantilever support 7 , and bed 8 adjacent to the inner surface wall 51 . Accordingly, a sewing machine including the main frame 1 A prevents horizontal and vertical vibrations of the main frame 1 A caused by the reciprocating motion of the needle 16 , thereby performing a smooth stitch forming action.
[0063] In addition, the reinforcing member 60 has a semicircle hollow section to achieve a light weight and provide sufficient rigidity. The reinforcing member 60 is formed integrally with the back panel wall 250 . Accordingly, process for manufacturing the main frame 1 A is simplified.
[0064] In the embodiment described above, the reinforcing member 60 has one end extending to the point adjacent to the side wall 251 placed at the tip of the arm 6 , and the other end extending to the point adjacent to the side wall 251 placed at the tip of the bed 8 . In another embodiment, the reinforcing member 60 may extend to a certain point between the arm 6 and the bed 8 It is preferable that the reinforcing member 60 is provided around at least the space 9 . In this case, the arrangement of the reinforcing member 60 may have a J-shape, C-shape, or a rectangular shape with one open side.
[0065] Auxiliary Reinforcing Member
[0066] Referring to FIGS. 4 and 5, the back panel wall 250 of the main frame 1 A has an auxiliary reinforcing member 66 formed integrally therewith. The auxiliary reinforcing member 66 is placed substantially parallel to the reinforcing member 60 outside thereof at a predetermined interval. The auxiliary reinforcing member 66 is placed in a continuous manner described as follows: The auxiliary reinforcing member 66 extends from a certain point between the cantilever support 7 and the side wall 251 at the arm 6 along the longitudinal direction of the arm 6 within the arm 6 to one end of the cantilever support 7 . The auxiliary reinforcing member 66 is then curved in a semicircle shape within the cantilever support 7 to extend to one end of the bed 8 . The auxiliary reinforcing member 66 further extends from the other end of the cantilever support 7 along the bed 8 with in the bed 8 to the point adjacent to the side wall 251 opposing to the cantilever support 7 . As describe above, the parallel arrangement of the reinforcing member 60 and the auxiliary reinforcing member 66 leads to a uniform filling to the interior of the back panel wall 250 between the reinforcing member 60 and the auxiliary reinforcing member 66 with synthetic resin, thereby preventing weld line and shrinkage appearing on the back panel wall 250 . As a result, the main frame 1 A can obtain a good appearance.
[0067] Referring to FIG. 7( c ), the auxiliary reinforcing member 66 has the substantially semicircle cross section similar to that of the reinforcing member 60 . The auxiliary reinforcing member 66 has a hollow tubular shape having a hollow space 6 B within the auxiliary reinforcing member 66 . The auxiliary reinforcing member 66 is formed integrally with the back panel wall 250 in a manner to project from the interior of the back panel wall 250 of the main frame 1 A. The reason why the auxiliary reinforcing member 66 has a tubular shape is the same as that of the reinforcing member 60 . Additionally, a method to form the auxiliary reinforcing member 66 is the same as that of the reinforcing member 60 .
[0068] The above arrangement of the auxiliary reinforcing member 66 ensures the rigidity of the back panel wall 250 . Therefore, a sewing machine including the above main frame 1 A can advantageously prevent horizontal and vertical vibrations of the main frame 1 A caused by the reciprocating motion of the needle 16 , thereby performing smooth stitch forming action.
[0069] In the above embodiment, the main frame 1 A is provided with the reinforcing member 60 and the auxiliary reinforcing member 66 , while the frame cover 1 B does not has any reinforcing member and auxiliary reinforcing member (See FIG. 11). The reason why frame cover 1 B has no reinforcing member is as follows: the main frame 1 A accommodates the stitch forming mechanism including the tope mechanism 3 for reciprocating the needle 16 and the lower mechanism 4 for rotating the rotary hook 23 . Therefore, vibrations or displacement are more easily induced to the main frame 1 A than the frame cover 1 B. However, the frame cover 1 B may be provided with a reinforcing member or an auxiliary reinforcing member, if necessary. In that case, the frame cover 1 B obtains stronger rigidity.
[0070] Inside Wall Reinforcing Rib
[0071] As shown in FIGS. 4 and 5, an inside wall reinforcing rib 70 for reinforcing the inner surface wall 51 of the main frame 1 A facing the space 9 is provided on the inside of the back panel wall 250 around the periphery of the space 9 . A lot of inside wall reinforcing ribs 70 are provided around the periphery of the space 9 from the joint of the arm 6 and the cantilever support 7 to the joint of the cantilever support 7 and the bed 8 .
[0072] The inside wall reinforcing rib 70 comprises a partitioning rib 71 spaced from the inner surface 51 and a plurality of intermediate ribs 72 intersecting with the inner surface 51 and partitioning rib 71 . The partitioning rib 71 extends from the inside of the back panel wall 250 and parallel to the inner surface wall 51 in a continuous manner. The intermediate rib 72 extends from the inside of the back panel wall 250 between the inner surface wall 51 and the partitioning rib 71 at a constant intervals perpendicularly to the back panel wall 250 . The intermediate rib 72 connects the inner surface wall 51 to the partitioning rib 71 , and connects the inner surface wall 51 and the partitioning rib 71 to the back panel wall 250 . The above arrangement of the inner surface wall 51 , the partitioning rib 71 , and the intermediate ribs 72 provides a plurality of cells (partitioning chamber) 73 in the space between the inner surface 51 and partitioning rib 71 . The intermediate ribs 72 are arranged radially from a center point located in the space 9 , because the inner surface wall 51 surrounding the space 9 has a semicircle shape. Accordingly, each intermediate rib 72 intersects the inner surface 51 and partitioning rib 71 at a perpendicular angle. Thus, the arrangement of the ribs is optimized, thereby reinforcing the inner surface wall 51 advantageously.
[0073] The above structure of the inside wall reinforcing ribs 70 provides the rigidity equal to that of the inner surface wall 51 having a considerable thickness. In other words, the above structure of the inside wall reinforcing ribs 70 ensures the rigidity over the back panel wall 250 from the area adjacent to the joint of the arm 6 and the cantilever support 7 , through the cantilever support 7 , to the area adjacent to the joint of the cantilever support 7 and the bed 8 . A sewing machine having the main frame 1 A can prevent horizontal and vertical vibrations of the main frame 1 A caused by the reciprocating motion of the needle 16 , thereby performing a smooth stitch forming action.
[0074] In the above embodiment, the inside wall reinforcing ribs 70 are provided on the back panel wall 250 from the joint of the arm 6 and the cantilever support 7 through the 7 through the 7 to the joint of the cantilever support 7 and the bed 8 . In another embodiment, the inside wall reinforcing rib 70 may be formed over the whole of the inner surface wall 51 . In the above embodiment, a lot of intermediate ribs 72 are provided. However, in another embodiment, the number of the intermediate ribs 72 may be only one or a few. Each of the intermediate ribs 72 may be coupled or crossed to each other, so that the resultant arrangement of the intermediate ribs 72 may have honeycomb or diagram shape.
[0075] As described above, the hollow reinforcing member 60 having a substantially semicircle shape is formed integrally with the back panel wall 250 around the inner surface wall 51 . In other words, both the reinforcing member 60 and the inside wall reinforcing rib 70 are formed at the substantially same positions on the inner surface wall 51 . Especially, the reinforcing member 60 is located near the back panel wall 250 inside of the inside wall reinforcing rib 70 . The inside wall reinforcing rib 70 projects from the surface of the reinforcing member 60 . The above structure is necessary to obtain considerable reinforcement, because stress induced by the reciprocating motion of the needle 16 is concentrated on the inner surface wall 51 . In addition, the space around the inner surface wall 51 has sufficient spare room because the stitch forming mechanism is not mounted. Therefore, the inside wall reinforcing rib 70 having a considerable height can be formed.
[0076] Outside Wall Reinforcing Rib
[0077] As shown in FIGS. 4 and 5, outside wall reinforcing ribs 80 are formed in a matrix shape over nearly the entire inside of the back panel wall 250 . The outside wall reinforcing rib 80 projects from the inside of the back panel wall 250 . The outside wall reinforcing rib 80 is formed of vertical ribs 81 vertically oriented when the sewing machine is placed on a working surface, and horizontal ribs 82 oriented horizontally when the sewing machine is in the same position. As shown in FIGS. 6 (A) and 6 (B), these vertical ribs 81 and horizontal ribs 82 are approximately perpendicular to the back panel wall 250 . The ends of the vertical ribs 81 and horizontal ribs 82 are joined with the side wall 251 on the side portions of the main frame 1 A. The spaces surrounded by pairs of intersecting vertical ribs 81 , 81 and horizontal ribs 82 , 82 form approximately square or rectangular shaped cells 83 . Hence, a plurality of cells 83 are formed on the back side of the back panel wall 250 .
[0078] Among the cells 83 , the outside wall reinforcing rib 80 defining a cell 83 having a wider area is formed to have a higher height from the back panel wall 250 , compared to a cell 83 having a narrower area. The above structure of the cell 83 will be explained with respect to a wider cell 83 A located on the right side of the arm conducting shaft supports 144 in the cantilever support 7 (see FIGS. 4 and 5), and a narrower cell 83 B located on the lower-right side of the needle bar holder mount 141 in the arm 6 (see FIGS. 4 and 5).
[0079] As shown in FIG. 5, the vertical length X of the wider cell 83 A is identical to the vertical length U of the narrower cell 83 B. On the other hand, the horizontal length Y of the wider cell 83 A is longer more than two times of the horizontal length V of the narrower cell 83 B. Thus, the area of the wider cell 83 A is wider than that of the narrower cell 83 B.
[0080] Referring to FIG. 6(A), the height Z from the 250 of the outside wall reinforcing rib 80 constituting the wider cell 83 A (horizontal rib 82 ) is higher than the height W from the back panel wall 250 of the outside wall reinforcing rib 80 constituting the narrower cell 83 B (vertical rib 81 ). In the case where the outside wall reinforcing ribs 80 have different height from each other due to requirements for a design of the main frame 1 A, the wider area of the higher outside wall reinforcing rib 80 and the narrower area of the narrower outside wall reinforcing rib 80 lead to the uniform rigidity over the whole of the back panel wall 250 . Accordingly, the action of stress on the particular point on the back panel wall 250 can be avoided. Thus, the main frame 1 A ensures considerable rigidity as a whole.
[0081] The outside wall reinforcing rib 80 on the accommodating part for the stitch forming mechanism in the arm 6 or the bed 8 has a lower height from the back panel wall 250 than those of the outside wall reinforcing ribs 80 on the inside of the back panel wall 250 other than the accommodating part. In other words, as described above, the narrower cell 83 B is located on the right-lower side of the needle bar holder mount 141 for mounting the needle bar holder 14 constituting the tope mechanism 3 , thereby corresponding to the part accommodating the stitch forming mechanism. Therefore, the outside wall reinforcing rib 80 (vertical rib 81 ) has a relatively lower height W from the back panel wall 250 so as to face the stitch forming mechanism at a closer distance. On the other hand, the wider cell 83 A is not a part for accommodating the stitch forming mechanism. Accordingly, as described above, the outside wall reinforcing rib 80 (horizontal rib 82 ) has a relatively higher height 2 form the back panel wall 250 . However, the above structure may lead to insufficient rigidity over the part for accommodating the stitch forming mechanism. To overcome the above problem, the narrower area of the cell 83 , that is, the formation of the narrower cell 83 B, results in the increase of the rigidity thereof. The resultant rigidity is substantially the same as that of the wider cell 83 A. Accordingly, the concentration of stress to a certain point of the back panel wall 250 can be prevented, so that the main frame 1 A can obtain sufficient rigidity.
[0082] The above arrangement of the outside wall reinforcing rib 80 ensures the sufficient rigidity of the back panel wall 250 , thereby minimizing or restricting distortion appearing on the back panel wall 250 of the arm 6 due to the reciprocating motion of the needle 16 . The above arrangement of the outside wall reinforcing rib 80 also minimizes distortion appearing on the back panel wall 250 of the cantilever support 7 and the bed 8 due to the distortion of the arm 6 . In this embodiment, the outside wall reinforcing ribs 80 extend in vertical and horizontal directions on the back panel wall 250 to define the cells 83 . This arrangement results in the sufficient rigidity of the back panel wall 250 in the case where the outside wall reinforcing rib 80 is not allowed to have a higher height in order that the main frame 1 A accommodates the stitch forming mechanism. Accordingly, a sewing machine having the above main frame 1 A can prevent vertical and horizontal vibrations of the main frame 1 A caused by the reciprocating motion of the needle 16 , thereby performing a smooth stitch forming action.
[0083] In another embodiment, the outside wall reinforcing rib 80 may not be formed over the whole back panel wall 250 , but be formed over only a part of the back panel wall 250 which needs sufficient rigidity of the back panel wall 250 for accommodating the stitch forming mechanism. In another embodiment, the outside wall reinforcing ribs 80 may be arranged in order that the cells 83 have hexagonal or octagonal shapes.
[0084] It should be noted that the inside wall reinforcing rib 70 has a higher height from the back panel wall 250 than that of the outside wall reinforcing rib 80 . More specifically, as shown in FIG. 8(A), at the base end of the arm 6 , the inside wall reinforcing rib 70 is formed at a height from the back panel wall 250 reaching the dividing plane 52 . In contrast, the vertical ribs 81 reach approximately halfway to the dividing plane 52 from the back panel wall 250 . As shown in FIG. 8(B), in the center portion of the cantilever support 7 , the intermediate ribs 72 have a height from the sidewall 50 reaching the dividing plane 52 . In contrast, the horizontal ribs 82 reach less than half the height of the dividing plane 52 from the sidewall 50 . A high rigidity is necessary for the inner surface wall 51 since stress generated by the vertical movement of the needle 16 is concentrated in this area. On the other hand, these height differences are necessary to maintain space at the inside of the back panel wall 250 for accommodating the stitch forming mechanism including the top mechanism 3 and the lower mechanism 4 .
[0085] Couplings
[0086] As shown in FIGS. 4 and 5, a plurality of couplings 90 , 92 , 94 , and 96 are provided in the back panel wall 250 of the main frame 1 A for joining the main frame 1 A to the frame cover 1 B. The coupling 90 is formed near the inner surface wall 51 in the area adjacent to the joint of the bed 8 and the cantilever support 7 . More specially, the coupling 90 is placed in the vicinity of the inside wall reinforcing rib 70 and the reinforcing member 60 . The above arrangement of the coupling 90 is aimed at preventing distortion of the arm 6 and the cantilever support 7 which causes swings of the top portion of the cantilever support 7 during the reciprocating motion of the needle 16 . The coupling 92 is formed near the inner surface wall 51 at the joint area of the arm 6 and the cantilever support 7 . More particularly, the coupling 92 is placed in the vicinity of the inside wall reinforcing rib 70 and the reinforcing member 60 . The coupling 94 is formed near the inner surface wall 51 in the vicinity of the end of the inside wall reinforcing rib 70 near the arm 6 . The couplings 92 , 94 are placed on the circumference of the semicircle of the space 9 at constant intervals with respect to the coupling 90 . A plurality of couplings 96 are formed on the sides and the corners of the inside of the back panel wall 250 in order to couple the main frame 1 A and the frame cover 1 B by a uniform pressure.
[0087] Screw holes 91 , 93 , 95 , and 97 are formed inside the couplings 90 , 92 , 94 , and 96 . The main frame 1 A and frame cover 1 B can be detachably joined together by inserting screws (not shown) in the screw holes 91 , 93 , 95 , and 97 when the couplings 90 , 92 , 94 , and 96 are aligned with couplings 190 , 192 , 194 , and 196 (see FIG. 11) provided in corresponding positions on the frame cover 1 B. Accordingly, the sewing machine is easily assembled by mounting the stitch forming mechanism to the main frame 1 A, and then screwing the frame cover 1 B to the main frame 1 A, thereby enabling cost reductions. In the case of maintenance, only undoing the screws leads to remove of the frame cover 1 B from the main frame 1 A, so that all the stitch forming mechanism is exposed. Therefore, the maintenance work is facilitated. In the present embodiment, screws are used to join the main frame 1 A to the frame cover 1 B, but bolts and nuts may also be used in place of the screws.
[0088] When stress induced by the reciprocating motion of the needle 16 forces the inner surface wall 51 of the main frame 1 A and an inner surface wall 161 of the frame cover 1 B to relatively move in a vertical or horizontal directions, relative movement of the main frame 1 A and the frame cover 1 B is restricted because a plurality of couplings 190 , 192 , and 194 (see FIG. 11) are arranged around the inner surface walls 51 , 161 . Therefore, the inner surface wall 51 of the main frame 1 A remains contact with the inner surface wall 161 of the frame cover 1 . A appropriate coupling between the main frame 1 A and the frame cover 1 B is maintained. Stress is transmitted from the main frame 1 A including the stitch forming mechanism which generates vibrations to the frame cover 1 B through the inner surface walls 51 , 161 which are contact to each other, thereby dispersing over the whole frame 1 . The stress dispersion ensures the sufficient rigidity of the frame 1 . As a result, a sewing machine including the frame 1 can prevent vertical vibrations and horizontal swings of the frame 1 induced by the reciprocating motion of the needle 16 , thereby performing a smooth stitch forming action.
[0089] In another embodiment, two or more than four couplings may be formed around the inner surface wall 51 of the main frame 1 A.
[0090] Protrusions
[0091] As shown in FIG. 4, protrusions 100 , 101 , 102 , and 103 are formed on the main frame 1 A at the dividing plane 52 . These protrusions 100 , 101 , 102 , and 103 engage with engaging units 111 , 112 , 113 , and 114 provided on the frame cover 1 B at the dividing plane 52 (see FIG. 11) when the main frame 1 A is joined with the frame cover 1 B. The protrusions 100 , 101 , 102 , and 103 are aimed at limiting the relative movement of the main frame 1 A and frame cover 1 B in the horizontal direction.
[0092] Next, the reason that the sewing machine frame of the present invention is configured in this way will be described. As mentioned earlier, a swing effect occurs in the horizontal direction in the top portion of the cantilever support 7 due to the vertical movement of the needle 16 . When this happens, the main frame 1 A and frame cover 1 B can move relative to one another in the horizontal direction, shifting their relative positions. When this positional shifting occurs, a reliable joined state cannot be maintained, resulting in insufficient rigidity, thereby promoting vibrations and displacement in the frame 1 . Moreover, the main frame 1 A and frame cover 1 B are joined by screws through considerable pressure, causing a large frictional coefficient. As a result, when the relative position of the main frame 1 A and frame cover 1 B shifts, they do not easily return to their original positions. The above construction is employed because it is necessary to prevent such shifting in the relative position of the main frame 1 A and frame cover 1 B from occurring. With this construction, it is possible to maintain sufficient rigidity in the frame 1 .
[0093] As shown in FIG. 9(A), the protrusion 100 protrudes from the bottom of the arm 6 at the dividing plane 52 substantially perpendicular to the frame cover 1 B and near the border between the horizontal portion on which the mechanism for reciprocally driving the needle 16 is supported and the semicircular portion by which the space 9 is formed. An opening 143 is formed in the front end of the arm 6 from which the reciprocally driving mechanism protrudes downward. The protrusion 100 is positioned on one side of the opening 143 . The protrusion 100 fits in the engaging unit 111 provided on the arm 6 of the frame cover 1 B (see FIG. 11). This configuration prevents relative movement of the main frame 1 A and frame cover 1 B generated by vibrations and displacement at the dividing plane 52 of arm 6 .
[0094] As shown in FIG. 9(B), the protrusions 101 and 102 protrude from the top of the bed 8 at the dividing plane 52 , that is, at both ends of an opening 149 approximately perpendicular to the frame cover 1 B. The opening 149 is aimed for exposing rotary hook 23 . The protrusions 101 , 102 are fitted into engaging units 112 , 113 provided in the bed 8 of the frame cover 1 B (see FIG. 11). The above arrangement can prevent relative movement of both the main frame 1 A and the frame cover 1 B caused by vibrations and displacement at the dividing plane 52 of the bed 8 in the main frame 1 A and the frame cover 1 B.
[0095] Referring to FIGS. 8 (B), 8 (C), the protrusion 103 protrudes to the frame cover 1 B being coupled at a predetermined point on the dividing plane 52 around the space 9 . The predetermined point is placed on the intermediate rib 72 constituting the inside wall reinforcing rib 70 in the vicinity of a cross point with the inner surface wall 51 around the space 9 . The protrusion 103 fits a channel-shaped engaging unit 114 (see FIG. 11) provided the periphery of the frame cover 1 B facing the space 9 . The above structure prevents vibrations and displacement at the dividing plane 52 around space 9 , thereby restricting relative movement of the coupled main frame 1 A and frame cover 1 B.
[0096] Referring to FIG. 9(A), an engaging unit 110 for receiving the protrusion 104 (see FIG. 11) protruding from the dividing plane 52 below the arm 6 of the frame cover 1 B. The place of the engaging unit 110 is on the dividing plane 52 below the arm 6 of the main frame 1 A. The above arrangement prevents vibrations and displacement at the dividing plane 52 of the arm 6 of the coupled main frame 1 A and frame cover 1 B, thereby restricting relative movement of the main frame 1 A and frame cover 1 B.
[0097] Top Edge
[0098] As shown in FIGS. 4 and 7(A), a top edge 120 is formed across the top of the main frame 1 A for contacting the frame cover 1 B. A raised step 121 is formed across nearly the entire top edge 120 , the bottom of raised step 121 protruding toward the frame cover 1 B. The protruding portion of the raised step 121 fits into a recessed step 126 formed in a top edge 125 of the frame cover 1 B for contacting the main frame 1 A (see FIG. 11). By engaging the raised step 121 with the recessed step 126 from above, this construction can limit the relative movement of the main frame 1 A in the upward direction.
[0099] Next, the reason that the sewing machine frame of the present invention is configured in this way will be described. As mentioned earlier, the portion of the main frame 1 A near the arm 6 vibrates in the vertical direction due to the vertical movement of the needle 16 . In particular, the main frame 1 A on which the top mechanism 3 is mounted for supporting the needle 16 tends to move in the upward direction. When this happens, the main frame 1 A and frame cover 1 B can move relative to one another in the vertical direction, shifting their relative positions. When this positional shifting occurs, a reliable joined state cannot be maintained, resulting in insufficient rigidity, thereby promoting vibrations and displacement in the frame 1 . Moreover, the main frame 1 A and frame cover 1 B are joined by screws through considerable pressure, causing a large frictional coefficient. As a result, when the relative position of the main frame 1 A and frame cover 1 B shifts, they do not easily return to their original positions. The above construction is employed because it is necessary to prevent such shifting in the relative position of the main frame 1 A and frame cover 1 B from occurring. With this construction, it is possible to maintain sufficient rigidity in the frame 1 .
[0100] While the raised step 121 in the present embodiment is formed across nearly the entire length of the top edge 120 of the main frame 1 A that contacts the frame cover 1 B, it is not necessary for the raised step 121 to span the entire length of the top edge 120 . In view of the reason described above for forming the raised step 121 , however, it is desirable that the raised step 121 be formed on the top edge 120 at least at portions of the main frame 1 A corresponding to the arm 6 . Similarly, the recessed step 126 (see FIG. 11) should be formed on the top edge 125 at least on portions of the frame cover 1 B that correspond to the arm 6 . With this construction, it is possible to achieve sufficient rigidity for the arm 6 .
[0101] A bottom edge 130 is formed across the bottom of the main frame 1 A for contacting the frame cover 1 B. A raised step 131 is formed across nearly the entire length of the bottom edge 130 , the top of the raised step 131 protruding toward the frame cover 1 B. As shown in FIG. 7(B), the raised step 131 comprises an insertion part 132 for inserting into a recessed step 136 (see FIG. 11) formed on a bottom edge 135 of the frame cover 1 B for contacting the main frame 1 A; a sliding surface 133 for guiding the raised step 131 into the recessed step 136 ; and an engaging wall 134 for engaging in the recessed step 136 after the recessed step 136 has been slid to a prescribed position. By inserting the insertion part 132 in the recessed step 136 of the frame cover 1 B and engaging the sliding surface 133 with the bottom of the recessed step 136 , it is possible to limit relative movement of the main frame 1 A in the downward direction.
[0102] Next, the reason that the sewing machine frame of the present invention is configured in this way will be described. As mentioned earlier, the portion of the main frame 1 A tends to move upward due to the vertical movement of the needle 16 . When this happens, the bed 8 of the frame cover 1 B engaged with the main frame 1 A attempts to move downward relative to the main frame 1 A. As a result, the frame cover 1 B shifts vertically from the main frame 1 A, promoting the generation of vibrations and displacement in the frame 1 . Hence, it is necessary to prevent such shifting in the relative position of the main frame 1 A and frame cover 1 B from occurring. With this construction, it is possible to maintain sufficient rigidity in the frame 1 .
[0103] While the raised step 131 in the present embodiment is formed across nearly the entire length of the bottom edge 130 of the main frame 1 A that contacts the frame cover 1 B, it is not necessary for the raised step 131 to span the entire length of the bottom edge 130 . In view of the reason described above for forming the raised step 131 , however, it is desirable that the raised step 131 be formed on the bottom edge 130 at least at portions of the main frame 1 A corresponding to the bed 8 . Similarly, the recessed step 136 (see FIG. 11) should be formed on the bottom edge 135 at least on portions of the frame cover 1 B that correspond to the bed B. With this construction, it is possible to achieve sufficient rigidity for the bed 8 .
[0104] Here, the sliding surface 133 of the raised step 131 is retracted further internally than the back panel wall 250 of the main frame 1 A. When the recessed step 136 of the frame cover 1 B overlaps this portion, the sidewall of the main frame 1 A and frame cover 1 B become the same height. Accordingly, by engaging the main frame 1 A with the frame cover 1 B, the sidewall of the main frame 1 A and frame cover 1 B forms a continuous surface at this point, improving the appearance of the frame 1 .
[0105] While a detailed construction of the raised step 121 described above is not shown in the drawings, this construction is similar to the raised step 131 of the bottom edge 130 shown in FIG. 7(B). However, the raised step 121 is vertically symmetrical to the raised step 131 .
[0106] Flame Cover
[0107] Next, the frame cover 1 B of the frame 1 will be described with reference to FIGS. 10 through 15. FIG. 10 is a perspective view showing the external appearance of the frame cover 1 B FIG. 11 is a perspective view showing the internal construction of the frame cover 1 B. FIG. 12 is a plan view showing the internal construction of the frame cover 1 B. FIG. 13 is a cross-sectional view along the plane of the frame cover 1 B indicated by the arrows I in FIG. 12. FIG. 14(A) is a cross-sectional view along the plane of the frame cover 1 B indicated by the arrows J in FIG. 12. FIG. 14(B) is an enlarged view showing the lower end of the frame cover 1 B. FIG. 15(A) is an enlarged plan view along the plane of the frame cover 1 B indicated by the arrows K in FIG. 12. FIG. 15(B) is an enlarged plan view along the plane of the frame cover 1 B indicated by the arrows L in FIG. 12.
[0108] As shown in FIG. 10, the frame cover 1 B Comprises the arm 6 , cantilever support 7 , and bed 8 , and is integrally formed of a synthetic resin with the arm 6 , cantilever support 7 , and bed 8 . The semicircular area surrounded by the arm 6 , cantilever support 7 , and bed 8 is the space 9 .
[0109] In addition, the frame cover 1 B comprises a front panel wall 252 constituting a front side of the sewing machine, and a side wall 253 extending from a peripheral edge 252 a of the front panel wall 252 . Especially, the surface of the frame cover 1 B facing the space 9 is designated as an inner surface wall 161 . A side portion of the arm 6 is provided with a thread cassette mount 203 in which a thread cassette including different kinds of thread.
[0110] Inside Wall Reinforcing Rib
[0111] As shown in FIGS. 11 and 12, an inside wall reinforcing rib 170 for reinforcing the inner surface wall 161 of the frame cover 1 B facing the space 9 is provided on the inside of the front panel wall 252 around the periphery of the space 9 . A lot of inside wall reinforcing ribs 170 are provided around the periphery of the space 9 from the joint of the arm 6 and the cantilever support 7 to the joint of the cantilever support 7 and the bed 8 in order to surround the inner surface wall 161 .
[0112] The inside wall reinforcing rib 170 comprises a partitioning rib 171 spaced from the inner surface 161 and a plurality of intermediate ribs 172 intersecting with the inner surface 161 and partitioning rib 171 . The partitioning rib 171 extends from the inside of the front panel wall 252 and parallel to the inner surface wall 161 in a continuous manner. The intermediate rib 172 extends from the inside of the front panel wall 252 between the inner surface wall 161 and the partitioning rib 171 at a constant intervals perpendicularly to the front panel wall 252 . The intermediate rib 172 connects the inner surface wall 161 to the partitioning rib 171 , and connects the inner surface wall 161 and the partitioning rib 171 to the front panel wall 252 The above arrangement of the inner surface wall 161 , the partitioning rib 171 , and the intermediate ribs 172 provides a plurality of cells 173 in the space between the inner surface 161 and partitioning rib 171 . The intermediate ribs 172 are arranged radially from a center point located in the space 9 , because the inner surface wall 161 surrounding the space 9 has a semicircle shape. Accordingly, each intermediate rib 172 intersects the inner surface 161 and partitioning rib 171 at a perpendicular angle. Thus, the arrangement of the ribs is optimized, thereby reinforcing the inner surface wall 161 advantageously.
[0113] The above structure of the inside wall reinforcing ribs 170 provides the rigidity equal to that of the inner surface wall 161 having a considerable thickness. In other words, the above structure of the inside wall reinforcing ribs 170 ensures the rigidity over the front panel wall 252 from the area adjacent to the joint of the arm 6 and the cantilever support 7 , through the cantilever support 7 , to the area adjacent to the joint of the cantilever support 7 and the bed 8 . A sewing machine having the frame cover 1 B can prevent horizontal vibrations and swings of the frame cover 1 B caused by the reciprocating motion of the needle 16 , thereby performing a smooth stitch forming action.
[0114] In the above embodiment, the inside wall reinforcing ribs 170 are provided on the front panel wall 252 from the joint of the arm 6 and the cantilever support 7 through the cantilever support 7 to the joint of the cantilever support 7 and the bed 8 . In another embodiment, the inside wall reinforcing rib 170 may be formed over the whole of the inner surface wall 161 . In the above embodiment, a lot of intermediate ribs 172 are provided. However, in another embodiment, the number of the intermediate ribs 172 may be only one or a few. Each of the intermediate ribs 172 may be coupled or crossed to each other, so that the resultant arrangement of the intermediate ribs 172 may have a honeycomb or diagram shape.
[0115] In order to further support the partitioning rib 171 of the inside wall reinforcing ribs 170 , a supplemental concave wall reinforcing rib 177 is provided outside of the inside wall reinforcing ribs 170 . The supplemental concave wall reinforcing rib 177 comprises an auxiliary partitioning rib 174 and a plurality of auxiliary intermediate ribs 175 . The auxiliary partitioning rib 174 is provided in a continuous manner along the partitioning rib 171 , while being spaced from the partitioning rib 171 . The auxiliary intermediate ribs 175 intersect the partitioning rib 171 and partitioning rib 174 at predetermined intervals, and form a plurality of cells or compartments 176 between the partitioning rib 171 and partitioning rib 174 . This construction attains further rigidity of the inner surface 161 of the space 9 . In another embodiment, supplemental concave wall reinforcing ribs may be provided outside of the inside wall reinforcing rib 70 of the main frame 1 A, if the main frame 1 A has sufficient spare space.
[0116] Outside Wall Reinforcing Rib
[0117] As shown in FIGS. 11 and 12, outside wall reinforcing ribs 180 are formed in a matrix shape over nearly the entire inside of the front panel wall 252 . The outside wall reinforcing rib 180 projects from the inside of the front panel wall 252 . The outside wall reinforcing rib 180 is formed of vertical ribs 181 vertically oriented when the sewing machine is placed on a working surface, and horizontal ribs 182 oriented horizontally when the sewing machine is in the same position. As shown in FIGS. 13 and 14(A), these vertical ribs 181 and horizontal ribs 182 are approximately perpendicular to the front panel wall 252 . The ends of the vertical ribs 181 and horizontal ribs 182 are joined with the side wall 253 on the side portions of the frame cover 1 B. The upper ends of the vertical ribs 181 are not coupled to the side wall 253 . This is because the upper portion of the frame cover 1 B needs sufficient space to accommodate thread cassettes and an LED display substrate. The spaces surrounded by pairs of intersecting vertical ribs 181 , 181 and horizontal ribs 182 , 182 form approximately square or rectangular shaped cells 183 . Hence, a plurality of cells 183 are formed on the back side of the front panel wall 252 .
[0118] Among the cells 183 , the outside wall reinforcing rib 180 defining a cell 183 having a wider area is formed to have a higher height from the front panel wall 252 , compared to a cell 183 having a narrower area. The outside wall reinforcing rib 180 on the accommodating part for the stitch forming mechanism in the arm 6 or the bed 8 has a lower height from the front panel wall 252 than those of the outside wall reinforcing ribs 180 on the inside of the front panel wall 252 other than the accommodating part. The cells 183 in the vicinity of the accommodating part for the stitch forming mechanism have narrower areas than those of the cells 183 provided on the area other than the accommodating part. The reason the above arrangement has been adopted is the same as that of the main frame 1 A, so that detailed explanation will be omitted.
[0119] The above arrangement of the outside wall reinforcing rib 180 ensures the sufficient rigidity of the front panel wall 252 , thereby minimizing or restricting distortion appearing on the front panel wall 252 of the arm 6 due to the reciprocating motion of the needle 16 . The above arrangement of the outside wall reinforcing rib 180 also minimizes distortion appearing on the front panel wall 252 of the cantilever support 7 and the bed 8 due to the distortion of the arm 6 . In this embodiment, the outside wall reinforcing ribs 180 extend in vertical and horizontal directions on the front panel wall 252 to define the cells 183 . This arrangement results in the sufficient rigidity of the front panel wall 252 in the case where the outside wall reinforcing rib 180 is not allowed to have a higher height in order that the frame cover 1 B accommodates the stitch forming mechanism. Accordingly, a sewing machine having the above frame cover 1 B can prevent vertical and horizontal vibrations of the frame cover 1 B caused by the reciprocating motion of the needle 16 , thereby performing a smooth stitch forming action.
[0120] It should be noted that the inside wall reinforcing rib 170 has a higher height from the front panel wall 252 than that of the outside wall reinforcing rib 180 . More specifically, as shown in FIG. 14(A), at the base end of the arm 6 , the inside wall reinforcing rib 170 is formed at a height from the front panel wall 252 reaching the dividing plane 52 . In contrast, the vertical ribs 181 reach approximately halfway to the dividing plane 52 from the front panel wall 252 . The reason is as follows: the inner surface wall 161 needs sufficient rigidity, because stress induced by the reciprocating motion of the needle 16 generally tends to concentrate on the inner surface wall 161 .
[0121] In another embodiment, the outside wall reinforcing rib 180 may be provided on the only part of the frame cover 1 B. Alternatively, the frame cover 1 B may have no outside wall reinforcing rib 180 . The frame cover 1 B does not need so high rigidity as that of the main frame 1 A.
[0122] Couplings
[0123] As shown in FIGS. 11 and 12, a plurality of couplings 190 , 192 , 194 , and 196 are provided in the front panel wall 252 of the main frame 1 A for joining the main frame 1 A to the frame cover 1 B. The coupling 190 , 192 , 194 , and 196 are placed at positions corresponding to the positions of the couplings 90 , 92 , 94 , and 94 of the main frame 1 A. The coupling 190 is formed near the inner, surface wall 161 in the area adjacent to the joint of the bed 8 and the cantilever support 7 . More specially, the coupling 190 is placed in the vicinity of the inside wall reinforcing rib 170 formed outside of the inner surface wall 161 . The above arrangement of the coupling 190 is aimed at preventing distortion of the arm 6 and the cantilever support 7 which causes swings of the top portion of the cantilever support 7 during the reciprocating motion of the needle 16 . The coupling 192 is formed near the inner surface wall 161 at the joint area of the arm 6 and the cantilever support 7 . More particularly, the coupling 192 is placed in the vicinity of the inside wall reinforcing rib 170 outside of the inner surface wall 161 . The coupling 194 is formed near the inner surface wall 161 in the vicinity of the end of the inside wall reinforcing rib 170 near the arm 6 . The couplings 192 , 194 are placed on the circumference of the semicircle of the space 9 at constant intervals with respect to the coupling 190 . A plurality of couplings 196 are formed on the sides and the corners of the inside of the back panel wall 250 in order to couple the main frame 1 A and the frame cover 1 B by a uniform pressure.
[0124] Screw holes 191 , 193 , 195 , and 197 are formed inside the couplings 190 , 192 , 194 , and 196 . The main frame 1 A and frame cover 1 B can be detachably joined together by inserting screws (not shown) in the screw holes 191 , 193 , 195 , and 197 when the couplings 190 , 192 , 194 , and 196 are aligned with couplings 90 , 92 , 94 , and 96 provided in corresponding positions on the main frame 1 A.
[0125] Engaging Unit
[0126] As shown in FIG. 11, engaging units 111 , 112 , 113 , and 114 are formed in the frame cover 1 B at the dividing plane 52 . These engaging units 111 , 112 , 113 , and 114 engage with protrusions 100 , 101 , 102 , and 103 provided on the main frame 1 A at the dividing plane 52 (see FIG. 4) when the main frame 1 A is joined with the frame cover 1 B and function to limit the relative movement of the main frame 1 A and frame cover 1 B in the horizontal direction.
[0127] As shown in FIG. 15(A), the engaging unit 111 is recessed in the bottom of the arm 6 on the frame cover 1 B at the dividing plane 52 and on one side of an opening 200 through which the mechanism for reciprocally driving the needle 16 protrudes downward. The engaging unit 111 engages with the protrusion 100 (see FIG. 4) formed on the arm 6 of the main frame 1 A. This construction limits relative movement of the main frame 1 A and frame cover 1 B generated by vibrations and displacement at the dividing plane 52 of the arm 6 .
[0128] As shown in FIG. 15(B), the engaging units 112 and 113 are recessed in the top of the bed 8 at the dividing plane 52 and on both sides of an opening 202 for exposing the rotary hook 23 . The engaging units 112 and 113 engage with the protrusions 101 and 102 formed on the bed 8 of the main frame 1 A (see FIG. 4). This construction restricts relative movement of the main frame 1 A and frame cover 1 B caused by vibrations and displacement at the dividing plane 52 of the bed 8 .
[0129] As shown in FIG. 11, the engaging unit 114 is formed in a continuous channel on the inner surface 161 of the space 9 . The protrusions 103 provided on the main frame 1 A (see FIG. 4) engage with this channel portion. This construction restricts relative movement of the main frame 1 A and frame cover 1 B caused by vibrations and displacement at the dividing plane 52 of the space 9 .
[0130] Protrusion
[0131] As shown in FIG. 15(A), the protrusion 104 is formed on the bottom of the arm 6 of the frame cover 1 B at the dividing plane 52 and on the opposite side of the opening 200 on which the engaging unit 111 is formed. The protrusion 104 protrudes substantially perpendicularly to the frame cover 1 B. The protrusion 104 fits in the engaging unit 110 provided on the arm 6 of the main frame 1 A (see FIG. 4). This construction restricts relative movement of the main frame 1 A and frame cover 1 B caused by vibrations and displacement at the dividing plane 52 of the arm 6 .
[0132] Recessed Top Edge
[0133] As shown in FIG. 14(A), the recessed step 126 is formed across nearly the entire top edge 125 on the frame cover 1 B that contacts the main frame 1 A for accommodating the raised step 121 formed on the top edge 120 of the main frame 1 A and engaging the raised step 121 from the top. As shown in FIG. 14(B), the recessed step 126 comprises an engaging wall 127 protruding toward the main frame 1 A for engaging the raised step 121 of the main frame 1 A when the raised step 121 is guided to a prescribed position; a sliding surface 128 for guiding the raised step 121 ; and an accommodating portion 129 for accommodating the insertion part of the raised step 121 . By accommodating the insertion part of the raised step 121 in the accommodating portion 129 and when the sliding surface of the raised step 121 engages with the sliding surface 128 from above, it is possible to limit relative movement of the main frame 1 A in the upward direction.
[0134] The recessed step 136 is formed across nearly the entire bottom edge 135 of the frame cover 1 B that contacts the main frame 1 A for accommodating the raised step 131 formed on the bottom edge 130 of the main frame 1 A and engaging the raised step 131 from below. While a detailed construction of the recessed step 136 is not shown in the drawings, this construction is basically the same as the recessed step 126 of the top edge 125 shown in FIG. 14(B). However, the recessed step 136 Is vertically symmetrical to the recessed step 126 . By engaging the raised step 131 with the recessed step 136 , it is possible to limit the relative movement of the main frame 1 A in the downward direction.
[0135] It is understood that the foregoing description and accompanying drawings set forth the preferred embodiments of the invention at the present time. Various modifications, additions and alternative designs will, of course, become apparent to those skilled in the art in light of the foregoing teachings without departing from the spirit and scope of the disclosed invention. Thus, it should be appreciated that the invention is not limited to the disclosed embodiments but may be practiced within the full scope of the appended claims.
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a sewing machine frame for a sewing machine including an integral frame member, and reinforcing ribs. The integral frame member is made from a synthetic resin and provides an outer surface defining an external shape and an inner surface providing an internal space. The integral frame member includes a bed portion, a tower portion upstanding from the bed portion, and an arm portion extending from the tower portion in a cantilevered fashion. The reinforcing ribs are provided at substantially entire area of the inner surface for reinforcing the integral frame member.
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BACKGROUND OF THE INVENTION
This invention relates generally to integratable amplifier circuits having variable gain control, and more particularly, to an integratable amplifier circuit susceptible to fabrication in a monolithic, bipolar integrated circuit form in which logarithmic gain control over a wide gain range may be effectively provided.
Logarithmic, digitally variable gain controlled amplifiers are known in the art. Such conventional amplifiers often employ linear digital to analog converters (DAC) to generate the logarithmic function by piece-wise linear approximation. When using the linear DAC the maximum attenuation obtainable is related to the number of bits employed in the digital input. For example, for a 4 bit linear DAC the maximum attenuation is 1/(2 4 )=™=-24.1 dB. Accordingly, a 16 bit linear DAC is required to provide an attenuation of -96.3 dB=1/65,536 (2 16 =65,536). Thus, an undesirably large number of bits is required to achieve a wide attenuation range employing the known linear DAC.
Logarithmic, digitally variable gain controlled amplifiers have been utilized for volume control over a large dynamic range. A paper in the IEEE Journal of Solid-State Circuits, Vol. SC-16, No. 6, December 1981, pages 682-689 entitled "A Volume and Tone Control IC for Hi-Fi Audio" describes a digital volume control circuit fabricated as a monolithic integrated circuit employing a metal-oxide semiconductor (MOS) process. Such MOS process is not compatible with other receiver and audio functions that have been integrated utilizing a bipolar process.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the invention to provide an integratable amplifier circuit susceptible to fabrication in a monolithic, bipolar integrated circuit form with logarithmic gain control.
It is another object of the invention to provide the logarithmic gain control directly according to a binary input signal such that a wide range of attenuation is achievable for a minimized number of bits employed in the binary input signal.
It is a further object of the invention to provide a method of providing logarithmic, digitally variable gain control in an integratable variable gain controlled amplifier circuit that has a gain proportional to a control current being applied to a control input thereof.
In practicing the invention, an integratable, variable gain controlled amplifier circuit is provided which comprises an amplifier having a signal input, a control input and an output and having a gain that is proportional to a control current being applied to the control input. In addition, the gain controlled amplifier circuit includes a current generator for providing a biasing current; control means coupled to the current generator for dividing the biasing current according to a binary input signal to produce a control current equalling a predetermined fraction of the biasing current that corresponds to a predetermined logarithmic attenuation; and means for applying the control current to the control input, thereby providing the predetermined logarithmic attenuation in the amplifier.
Briefly, in accordance with the method of the present invention, a binary input signal is provided that relates to a desired logarithmic attenuation according to a predetermined rule. A biasing current is provided and is sequentially divided by a series of preselected fractions according to said binary input signal to produce a control current equalling a predetermined fraction of the biasing current. The control current is applied to a control input of the variable gain controlled amplifier circuit to provide the predetermined logarithmic attenuation therein
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1a is a schematic diagram of a current generator section of the novel logarithmic, digitally variable gain controlled amplifier according to the invention;
FIG. 1b is a schematic diagram of a first portion of a digital control section of the novel logarithmic, digitally variable gain controlled amplifier;
FIG. 1c is a schematic diagram of a remaining portion of the digital control section of FIG. 1b; and
FIG. 1d is a schematic diagram of a variable gain amplifier of the novel logarithmic, digitally variable gain controlled amplifier.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1a, there is shown a schematic diagram of a current generator section of a preferred embodiment of the logarithmic, digitally variable gain controlled amplifier constructed in accordance with the invention.
The current generator section comprises start-up and biasing circuitry 10, a plurality of PNP transistor current mirrors 12A, 12B, an NPN transistor current mirror 12C and an NPN transistor current source 12D. The current generator section is constructed in accordance with conventional integrated circuit (IC) technique in order to generate a biasing current, shown in FIG. 1a as I B , that is proportional to the absolute temperature. The temperature dependence of the biasing current I B is utilized to temperature stabilize the variable gain amplifier section that will be described hereinafter.
The start-up and biasing circuitry 10 includes resistors 14 and 32, a zener diode 16, a diode 18, a plurality of NPN transistors 20, 22, 24 and diodes 28, 30. The function of the circuitry 10 is to develop a bias for the base of a transistor 34 and to produce a start-up current for the current mirror 12A.
The series-connected resistor 14, zener diode 16 and diode 18 are coupled between the positive voltage supply terminal, +V supply and ground, as shown, to provide a start-up current in the collector of transistor 20. The base of the transistor 20 is coupled to the anode of both zener diode 16 and diode 18, and the emitter thereof is coupled through a resistor 32 to ground. The collector of transistor 20 is coupled to an input of current mirror 12A, as shown, so that this current mirror receives and "mirrors" the start-up current.
The collectors of the start-up transistors 22, 24 are coupled to the positive voltage supply terminal, +V supply . The base of transistor 24 is coupled to an output of the PNP transistor current mirror 12A and the emitter thereof is coupled to both the base of the transistor 22 and to the collector of an NPN transistor 26. The emitter of transistor 22 is coupled through the series-connected diodes 28, 30 and resistor 32 to ground, as shown. In addition, the emitter of the start-up transistor 22 is coupled to the base of a transistor 34 to provide a bias voltage therefor. The collector of transistor 34 is coupled to an input of the PNP transistor current mirror 12B and the emitter thereof is coupled to an output of current source 12D.
The biasing current I B is generated by the cooperative operation of the PNP transistor current mirror 12A and the NPN transistor current mirror 12C. The transistor current mirror 12A comprises a plurality of PNP transistors 36, 38, 40. The emitters of transistors 36, 38 are coupled through resistors 42,43, respectively, to the positive voltage supply terminal, +V supply . The base of transistor 36 is coupled to the base of transistor 38, with the base of transistor 36 shorted to its collector in the conventional manner. The emitter of transistor 40 is coupled to the shorted base and collector of transistor 36 with the base thereof coupled to the collector of transistor 38, as shown.
With the foregoing arrangement, the collector current of transistor 38 equals the collector current of transistor 40 according to the operation of conventional current mirrors. The collectors of transistors 38, 40 are coupled to the start-up circuitry 10 as described hereinbefore and to the current mirror 12C, as shown.
The NPN transistor current mirror 12C comprises a plurality of NPN transistors 42, 44, 46. The collectors of the transistors 42, 44 are coupled to the collectors of the transistors 40, 38, respectively. The base of transistor 42 is coupled to the base of transistor 46 with the base of transistor 46 shorted to its collector in the conventional manner. The emitter of transistor 44 is coupled to the shorted base and collector of transistor 46. The base of transistor 44 is coupled to the collector of transistor 42, as shown. With this arrangement, and particularly with the illustrated combination of mirrors 12A and 12C, the output emitter currents of the transistors 42, 46 are equal.
The transistor 46 is provided with an emitter having a junction area (8×) equal to eight times the junction area (1×) of the emitter of the transistor 42. This increase in the emitter junction area of transistor 46 results in a proportional decrease in the base emitter voltage of the transistor 46 for a given current flow. Thus, the base emitter voltage VBE 46 of the transistor 46 is less than the base emitter voltage VBE 42 of the transistor 42 with the emitter current of the same being equal. A resistor 48 is coupled between the emitter of the transistors 42, 46, so that the voltage difference between the base emitter voltage of the transistors 42, 46 appears across the resistor 48.
The value of the resistor 48 (R48) is selected to determine the desired magnitude of the biasing current, I B , that is defined as follows by the equation:
I.sub.B =2 (VBE 42-VBE 46)/R48
where I B is expressed in amperes, VBE 42 and VBE 46 are expressed in volts and R48 is expressed in ohms.
In addition, the emitter of transistor 42 is coupled to a biasing resistor 50, as shown. The output of the NPN transistor current mirror 12C is coupled via the resistor 50 to the anode of a diode 52. The cathode of the diode 52 is coupled to the collector of an NPN transistor 54 that is included in the NPN transistor current source 12D. The base of the NPN transistor 26 is coupled to the anode of the diode 52 and the emitter thereof is coupled to the base of the NPN transistor 54, as shown. Diode 52 is employed to provide a voltage which matches the base emitter voltage of the NPN transistor 26 so that the collector-base voltage of transistor 54 is held at or near zero. The reason for selecting this collector-base voltage for transistor 54 is because the bias and operating characteristics of transistor 54 will match the bias and operating characteristics of transistors 58 and 60 (FIG. 1b) and allow the currents of those three transistors to match each other according to the ratios of their base-emitter junction areas.
The NPN current source 12D additionally includes NPN transistors 56, 58, 60, with transistors 58, 60 shown in FIG. 1b. The base of the NPN transistor 54 is coupled to the bases of the transistors 56, (58), (60). The emitters of the transistors 54, 56, (58), (60) are grounded; accordingly, the magnitude of the base emitter voltages are equal for the transistors 54, 56, (58), and (60). The emitter currents of the transistors 54, 56, (58), and (60) are substantially equal to their respective collector currents.
The emitter of each of the transistors 54, 56, (58), (60) is provided with a selected junction area in order to determine the emitter current of the same. For example, transistors 54, 56 are shown as having twice the emitter junction area (2×) as the emitter junction area (1×) of transistor (60), with transistor (58) shown as having three times the emitter junction area (3×) as transistor (60). Accordingly, the emitter current of both transistors 54, 56 equals the biasing current, I B . The emitter current of transistor (58) equals the biasing current I B times the ratio 3×/2× or 3/2 I B . The emitter current of transistor (60) equals the biasing current I B times the ratio 1×/2× or 1/2I B . Thus, the input current I 1 that is applied (via the collectors of transistors 58 and 60) to the digital control section, shown in FIGS. 1b, 1c, equals the sum of the collector currents 3/2 I B , 1/2I B of transistors 58, 60 (FIG. 1b) or twice IB. Because the junction area of the transistor 58 is three times larger than the junction area of the transistor 60, the current supplied by the transistor 58 corresponds to 3/4I 1 , and the current supplied by the transistor 60 corresponds to 1/4I 1 . Those two currents (whose sum I 1 equals 2I b ) are progressively divided in the digital control section to produce a control current that is utilized to obtain a desired logarithmic attenuation in a variable gain amplifier section, shown in FIG. 1d, as will be described later herein.
Returning briefly to FIG. 1a, the PNP transistor current mirror 12B comprises a plurality of PNP transistors 62, 64, 66 interconnected as shown with resistors 68 and 70 in the usual manner. In operation, the mirror 12B receives a current from the collector of the transistor 34 and mirrors that current as I REF to the variable gain amplifier section that will be described later herein.
Referring now to FIGS. 1b, 1c, there are shown schematic diagrams illustrating the digital control section according to the invention. The first portion of the digital control section is illustrated in the schematic diagram of FIG. 1b with the remaining portion thereof shown in FIG. 1c.
The collector currents 3/4I 1 of transistor 58 and 1/4I 1 of transistor 60 are progressively divided in successive stages of the illustrated digital control section according to a binary input signal that is applied to nine binary control inputs, shown as G8, G7, G6, G5, G4, G3, G2, G1 and G0. The binary input signal comprises a binary word including nine bits corresponding to the nine control inputs G8-G0. The binary input signal is related to a desired logarithmic attenuation according to a predetermined rule, as illustrated immediately below.
Each of the nine bits is provided as either a logic 0 or a logic 1. In the illustrated embodiment, a logic 0 input bit provides zero dB reduction in gain and a logic 1 input bit provides a predetermined attenuation according to the significance of the bit. The most significant bit (MSB) is applied to the G8 binary control input and the least significant bit is applied to the G0 binary control input. For example, the predetermined attenuation corresponding to each of the nine input bits may be as shown in the following table, where Y represents a predetermined attenuation.
______________________________________ Relative Example Attenu- Attenuation ation in dBControl Significance Provided by provided by a 1Input of Bit a 1 Input input where Y = 48 db______________________________________G8 MSB.sup. Y .sup. 48G7 MSB-1 Y/2.sup.1 48/2 = 24G6 MSB-2 Y/2.sup.2 48/4 = 12G5 MSB-3 Y/2.sup.3 48/8 = 6G4 MSB-4 Y/2.sup.4 48/16 = 3G3 MSB-5 Y/2.sup.5 48/32 = 1.5G2 MSB-6 Y/2.sup.6 48/64 = 3/4G1 MSB-7 Y/2.sup.7 48/128 = 3/8G0 MSB-8 Y/2.sup.8 48/256 = 3/16______________________________________
For the example given, the maximum attenuation is obtained with a 1 input bit applied to all of the control inputs G8-G0 and is equal to the sum of attenuations in dB or approximately 95.8 dB. Thus, a total dynamic range of 95.8 dB is provided in approximately 0.2 dB steps with the nine control inputs.
The foregoing rule or relationship between the binary input signal and the attenuation provided can be expressed as follows for a nine stage digital control section:
B.sub.t =B.sub.8 ·A.sub.8 +B.sub.7 ·A.sub.7 + . . . +B.sub.0 ·A.sub.0 (1)
where
B t =total desired attenuation in d.b.;
B 0 -B 8 identify the available attenuation for each stage 0-8; and
A 0 -A 8 identify the bits (logic 1 or logic 0) of the binary input signal for stages 0-8, respectively; and ##EQU1## where n=0 through 8
and B n is the available attenuation for stage n.
In the digital control section, each bit of the binary input signal is applied via the corresponding one of the control inputs G8-G0 to the base of an NPN control transistor (such as transistor 94) which has a collector coupled to +V supply and an emitter which is coupled to an NPN transistor current divider circuit, as shown. Thus, with a logic 0 or low voltage input, the base of the control transistor is clamped to ground and the control transistor is thereby cut-off or rendered nonconductive. Alternatively, when the binary control input is a logic 1 or a logic high voltage, the base emitter junction of the control transistor is forward biased, thereby rendering the control transistor turned-on or conductive. As will be shown, when the control transistor of a particular stage is turned on, that stage provides attenuation, but when the control transistor is turned off, no attenuation is provided by that stage.
Referring now to the left portion of FIG. 1b, there is shown the first part of the digital control section including the control input G8 to which the MSB is applied. The collector currents 3/4I 1 of transistor 58 and 1/4I 1 of transistor 60 are divided according to the control bit that is applied to the G8 control input as follows.
The first NPN transistor current divider circuit comprising a plurality of switches, NPN transistors 72-92, is coupled to a control transistor 94 and is arranged to provide an output current of 1/256 I 1 with a 1 applied to the control input G8. The output current 1/256 I 1 corresponds to approximately 48 dB reduction in gain.
The emitter of each of the transistors 72-92 is provided with a predetermined relative junction area in order to determine the emitter current of the same. For example, transistor 74 is provided with three times the emitter junction area (3×) as the emitter junction area (1×) of the transistor 76. The sum of the emitter current of transistors 74, 76 equals the collector current of transistor 60 (1/4I 1 ). Thus, the emitter current of transistor 74 equals 3/4 of 1/4I 1 =3/16 I 1 and the emitter current of transistor 76 equals 1/4 of 1/4I 1 =1/16 I 1 , as determined by the relative emitter junction area of the transistors 74, 76.
The emitter of transistor 72 is coupled to the collector of the transistor 58, so that the emitter current of transistor 72 equals the collector current, 3/4I 1 , of transistor 58. The collector of transistor 72 is coupled to both the collector of transistor 74 and to the emitter of transistor 78, so that the emitter current of transistor 78 equals the sum of the collector currents of the transistors 72, 74. Thus, the emitter current of transistor 78 equals 3/4I 1 +3/16 I 1 or 15/16 I 1 .
The collector of transistor 82 is coupled to both the emitter of transistor 86, shown as having an emitter junction area of 3×, and to the emitter of transistor 88, shown as having an emitter junction area of 1×. The emitter (1×) of transistor 82 is coupled to both the emitter (3×) of transistor 80 and to the collector of transistor 76, so that the sum of the emitter currents of transistors 80, 82 equals the collector current of transistor 76 which equals 1/16 I 1 . Accordingly, the emitter current of the transistor 80 equals 3/4 of 1/16 I 1 =3/64 I 1 and the emitter current of the transistor 82 equals 1/4 of 1/16 I 1 =1/64 I 1 . Likewise, the sum of the emitter currents 86, 88 equals the collector current of the transistor 82 which equals 1/64 I 1 . As determined by the relative emitter junction area of transistors 86, 88, the emitter current of the transistor 86 is 3/4 of 1/64 I 1 =3/256 I 1 and the emitter current of the transistor 88 is 1/4of 1/64 I 1 =1/256 I 1 . The collector of the transistor 88 is coupled to the emitter of the transistor 90 so that the emitter current ot transistor 90 is also equal to 1/256 I 1 .
The collector of transistor 78 is coupled to both the collector of transistor 80 and to the emitter of transistor 84. Accordingly, the emitter current of transistor 84 equals the sum of the collector currents of the transistors 78, 80 which equals 15/16 I 1 +3/64 I 1 =63/64 I 1 . The collector of transistor 84 is coupled to the collector of transistor 86 and to the emitters of transistors 92 and 94. The sum of the emitter currents of transistors 92, 94 equals the sum of the collector currents of transistors 84, 86 which equals 63/64 I 1 +3/256 I 1 =255/256 I 1 .
A conventional PNP current mirror including PNP transistors 96, 98, 100 is coupled to the collectors of transistors 90, 92, as shown, to provide an output current I 1 out that is equal to the sum of the collector currents of transistors 90, 92. The current I 1 out is applied to the second stage of the digital control section which includes the binary control input G7.
The magnitude of I 1 out is determined by the control bit that is coupled through the control input G8 to the base of the NPN control transistor 94. For example, with a 0 or low voltage applied to the base of control transistor 94, the base emitter junction of transistor 94 is reverse biased and the control transistor 94 is thereby cut-off or rendered nonconductive. Thus, the emitter current of transistor 92 equals 255/256 I 1 with the emitter current of transistor 94 equal to zero as the emitter current of transistor 90 equals 1/256 I 1 , I 1 out equals 255/256 I 1 +1/256 I 1 =256/256 I 1 or I 1 .
Alternatively, when the binary control input is a 1 or logic high voltage, the base emitter junction of the control transistor 94 is forward biased, thereby rendering the control transistor turned-on or conductive and rendering the transistor 92 non-conductive. Consequently, the collector current of transistor 96 and I 1 out are now equal to 1/256 I 1 .
Thus, in the first current divider circuit that is coupled to the most significant binary control input, G8, the input current is divided to produce the fixed fraction, 1/256 I 1 corresponding to approximately 48 dB reduction in gain for a high binary control input. Alternatively, a low binary control input being applied to the control input G8 provides an I 1 out equal to I 1 and a zero db reduction in gain.
The collector of the PNP current mirror transistor 100 is coupled through a diode 102 to the collector of an NPN transistor 104. The anode of diode 102 is coupled to the base of an NPN transistor 106 and the cathode thereof is coupled to the collector of the transistor 104. The collector of transistor 106 is coupled through a diode 107 to the +V supply terminal and the emitter of transistor 106 is coupled to the base of transistor 104. The diode 102 is employed to provide a voltage matching the base emitter voltage of the NPN transistor 106. The base of the NPN transistor 104 additionally is coupled to the base of the transistors 108, 110. The emitters of the transistors 104, 108, 110 are grounded; accordingly, the magnitudes of the base emitter voltages are equal for the transistors 104, 108, 110 and the emitter currents for the same are proportional to the relative emitter junction areas as described hereinbefore.
An NPN transistor current divider circuit comprising a plurality of NPN transistors 108-120 is coupled to a control transistor 122 and is arranged to divide the current I 1 out by the fixed fraction 1/16 with a 1 or a logic high voltage being applied to the control input G7, thereby providing approximately 24 dB reduction in gain. Alternatively, the NPN transistor current divider circuit provides an undivided I 1 out when a 0 or logic low voltage is applied to the control input G7 corresponding to 0 dB reduction in gain. The NPN transistor current divider circuit, configured as shown, is coupled to the control input G7 to provide 1/16 I 1 out or I 1 out as follows.
The emitter of transistor 108 is provided with three times the junction area (3×) as the emitter junction area (1×) of the transistor 110. Accordingly, the emitter current of transistor 108 equals 3/4I 1 out and the emitter current of transistor 110 equals 1/4I 1 out, as determined by the relative emitter junction areas of the transistors 108, 110.
The emitter of transistor 112 is coupled to the collector of transistor 108 and thus conducts an emitter current that is equal to 3/4I 1 out. The collector of the transistor 110 is coupled to the emitters of both transistors 114, 116. Thus, the sum of the emitter currents of the transistors 114, 116 equals the collector current of the transistor 110 (1/4I 1 out). As determined by the relative emitter junction area of transistors 114, 116, the emitter curren of transistor 114 equals 3/4 of 1/4I 1 out =3/16 I 1 out and t the emitter current of transistor 116 equals 1/4 of 1/4I 1 out =1/16 I 1 out. The emitter of transistor 120 is coupled to the collector of transistor 116, as shown. Thus, the emitter current of transistor 120 equals the collector current of the transistor 116 or 1/16 I 1 out.
The collector of transistor 112 is coupled to the collector of transistor 114 and to the emitters of transistors 118, 122, as shown. The sum of the collector currents of transistor 112, 114 is equal to the sum of the emitter currents of transistors 118, 122. The sum of the collector currents of transistors 112, 114 equals 3/4I 1 out +3/16 I 1 out =15/16 I 1 out.
The base of the control transistor 122 is coupled to the control input G7 with the collector thereof coupled to +V supply . A logic 0 or a logic 1 control bit is applied to the control input G7 and is coupled thereby to the base of the NPN control transistor 122. As described hereinabove with respect to the control input G8 that is coupled to the similarly configured control transistor 94, with a logic 0 or low voltage applied to the base of the control transistor 122, the base emitter junction thereof is reverse biased so that the control transistor 122 is cut-off or rendered nonconductive. Thus, with a logic 0 control bit applied to the control input G7, the emitter current of transistor 118 equals 15/16 I 1 out with the emitter current of the control transistor 122 equal to nil. As the current in transistor 120 equals 1/16 I 1 out, the total output current of the second stage equals I 1 out when a logic zero is applied to the G7 input.
Alternatively, when a logic 1 control bit is applied to the control input G7, the control transistor 122 is turned-on and shunts the collector currents of transistors 112, 114 (15/16 I 1 out) to the +V supply . The sum of the collector currents of transistors 118, 120 is now equal to 1/16 I 1 out corresponding to approximately 24 dB reduction in gain for a logic 1 bit being applied to the control input G7. The sum of the collector currents of transistors 118, 120 is shown as I 2 out and is further divided according to the binary control bit that is applied to the binary control input G6 in the third stage of the digital control section.
An NPN transistor current divider circuit comprising a plurality of NPN transistors 124-130 is coupled to a control transistor 132 and is arranged to divide the current I 2 out by the fixed fraction 1/4 when a logic 1 is applied to the binary control input G6 corresponding to approximately 12 dB reduction in gain. Alternatively, a zero dB reduction in gain is provided when a logic 0 is applied to the binary control input G6.
The NPN transistor current divider circuit configured as shown, provides an output current, shown as I 3 out, that is equal to either I 2 out or 1/4I 2 out as will now be described.
The sum of the emitter currents of transistors 124, 126 equals the sum of the collector currents of transistors 118, 120 and is shown as I 2 out. As determined by the relative emitter junction areas, the emitter current of transistor 124 equals 3/4I 2 out and the emitter current of transistor 126 equals 1/4I 2 out. The emitter current of transistor 130 equals the collector current of transistor 126 (1/4I 2 out). The sum of the emitter currents of transisors 128, 132 equals the collector current, 3/4I 2 out, of transistor 124.
The control transistor 132 is turned-on by a logic 1 being applied to the control input G6 or alternatively is cut-off with a logic 0 being applied to the control input G6. When the input G6 receives a logic 1 , the transistor 132 shunts the collector current of transistor 124 to the +V supply and the transistor 128 is rendered nonconductive. Alternatively, the control transistor 132 is turned off when a logic 0 is applied to control input G6, and then the emitter current of transistor 128 equals 3/4I 2 out. Thus, the sum of the collector currents of transistors 128, 130 equals either 1/4I 2 out or I 2 out, corresponding respectively, to either a logic 1 or a logic 0 being applied to the control input G6.
A PNP transistor current mirror including a plurality of PNP transistors 134, 136, 138 is coupled to the collector of transistors 128, 130, as shown. The PNP current mirror provides an output current shown as I 3 out that is equal to the sum of the collector currents of transistors 128, 130. The current, I 3 out, is applied to the next stage of the digital control section which includes the binary control input G5.
The collector current, I 3 out, of transistor 138 is coupled through a diode 140 to the collector of an NPN transistor 142. The anode of diode 140 is coupled to the base of the transistor 144 and the cathode thereof is coupled to the collector of transistor 142, as shown. The collector of transistor 144 is coupled through the diode 107 to +V supply and the emitter of transistor 144 is coupled to the base of the transistor 142. The diode 140 provides a voltage matching the base emitter voltage of the NPN transistor 144. The base of the transistor 142 additionally is coupled to the base of transistors 146, 148. The emitters of the transistors 142, 146, 148 are grounded, so that the base-emitter voltages are equal for the transistors 142, 146, 148, and the emitter currents for the same are proportional to the relative emitter junction areas, as described hereinbefore.
An NPN transistor current divider circuit comprising the transistors 146-152 is coupled to a control transistor 154 and is arranged to divide the current I 3 out by the fixed fraction 1/2 when a logic 1 or a high voltage is applied to the control input G5, thereby providing approximately 6 dB reduction in gain. Alternatively, the NPN transistor current divider circuit provides an undivided I 3 out when a logic 0 or a low voltage is applied to the control input G5, which corresponds to a zero dB reduction in gain.
The transistors 146, 148 are provided with equal emitter junction areas so that the emitter current of each is equal to 1/2I 3 out. The emitter of transistor 152 is coupled to the collector of the transistor 148 and thus conducts an emitter current which is also equal to 1/2I 3 out. The emitter of transistor 150 is coupled to the emitter of the control transistor 154 and to the collector of the transistor 146. Thus, the sum of the emitter currents of transistors 150, 154 is equal to the collector current, 1/2I 3 out, of transistor 146. The collector of transistor 150 is coupled to the collector of transistor 152. Accordingly, the sum of the collector currents of transistors 150, 152, shown as I 4 out, equals 1/2I 3 out +1/2I 3 out or I 3 out when a logic 0 is applied to the control input G5 to turn off the control transistor 154. Alternatively, I 4 out equals 1/2I 3 out, the collector current of transistor 152, when a logic 1 control bit is applied to the control input G5 to turn on the control transistor 154 and to turn off the transistor 150.
The current I 4 out is further divided according to the control bit that is applied to the control input G4 in the next stage of the digital control section. An NPN transistor current divider circuit comprising the transistors 156-162 is coupled to a control transistor 164 and is arranged to divide the current, I 4 out by the fixed fraction 5/7 for a logic 1 or high voltage being applied to the control input G4, thereby providing approximately 3 dB reduction in gain. Alternatively, a zero dB reduction in gain is provided by the divider circuit with a logic 0 or low voltage being applied to the control input G4.
The sum of the emitter currents of transistors 156, 158 equals I 4 out. The transistors 156, 158 are provided with relative emitter junction areas so that the emitter current of transistor 156 equals 2/7 I 4 out and the emitter current of transistor 158 equals 5/7 I 4 out. The collector of transistor 156 is coupled to both the emitter of transistor 160 and to the emitter of the control transistor 164. Thus, with the control transistor 164 rendered nonconductive by a logic 0 being applied to the control input G4, the emitter current of transistor 160 equals 2/7 I 4 out and the total current output of this stage, indicated as I 5 out, equals 2/7 I 4 out plus 5/7 I 4 out, or an undivided I 4 out. Alternatively, with a logic 1 being applied to the control input G4, the control transistor 164 is turned-on to shunt the current from transistor 156 to +V supply , and the transistor 160 is rendered nonconductive. Accordingly, the sum of the collector currents of transistors 160, 162, shown as I 5 out, now equals 5/7 I out .
The current I 5 out is divided according to the control bit that is applied to the binary control input G3 by an NPN transistor divider circuit comprising transistors 166-172. This divider circuit is coupled to a control transistor 174 and is arranged to divide the current I 5 out by the fixed fraction 5/6 when a logic 1 is applied to the control input G3, thereby providing approximately 1.5 dB reduction in gain. Alternatively, the NPN current divider circuit provides an undivided I 5 out when a logic 0 is applied to the control input G3. The latter condition corresponds to a zero dB reduction in gain.
In the divider circuit, configured as shown, the sum of the emitter currents of the transistors 166, 168 equals I 5 out. The transistors 166, 168 are provided with relative emitter junction areas so that the emitter current of transistor 166 equals 1/6 I 5 out and the emitter current of transistor 168 equals 5/6 I 5 out.
The collector of transistor 166 is coupled to the emitters of both transistors 170, 174. Thus, the emitter current of transistor 170 equals 1/6 I 5 out when a logic 0 is applied to the control input G3 and the control transistor 174 is thereby rendered nonconductive. Alternatively, the emitter current of transistor 170 equals zero when a logic 1 is applied to the control input G3 and the control transistor 174 is thereby turned-on. Accordingly, the sum of the collector currents of the transistors 170, 172 equals either I 5 out or 5/6 I 5 out, corresponding to a logic 0 or a logic 1 being applied to the control input G3.
A PNP transistor current mirror comprising transistors 176,178, 180 is coupled to the collectors of transistors 170, 172, as shown. The PNP current mirror provides an output current shown as I 6 out that is equal to the sum of the collector currents of transistors 170, 172.
The current I 6 out is applied to the next stage of the digital control section which includes the binary control input G2. Toward this end, the collector of the current mirror transistor 180 is coupled through a diode 182 to the collector of the NPN transistor 184. The anode of diode 182 is coupled to the base of a transistor 186, shown in FIG. 1c, and the cathode thereof is coupled to the collector of transistor 184. The collector of transistor (186) is coupled through the diode 107 to +V supply , and the emitter of transistor (186) is coupled to the base of transistor 184. The base of transistor 184 additionally is coupled to the bases of transistors 188, 190 that are shown in FIG. 1c.
Referring now to FIG. 1c, there is shown a schematic diagram of the remaining stages of the digital control section. An NPN transistor current divider circuit comprising transistors 188-200 is coupled to a control transistor 202 and is arranged to divide the current I 6 out by the fixed fraction 11/12 when a logic 1 is applied to the control input G2, thereby providing approximately 3/4 dB reduction in gain. Alternatively, this NPN transistor current divider circuit provides a zero dB reduction in gain when a logic 0 is applied to the control input G2. The NPN transistor current divider, configured as shown, provides either 11/12 I 6 out or an undivided I 6 out as follows.
The emitter current of transistor 188 equals 1/6 I 6 out and the emitter current of transistor 190 equals 5/6 I 6 out as determined by the relative junction emitter areas of the same. The emitter current of transistor 196 equals the collector current of transistor 190 (5/6 I 6 out). The sum of the emitter currents of transistors 192, 194 equals the collector current of transistor 188 (1/6 I 6 out) and as both transistors conduct equally, they each conduct an emitter current equal to 1/12 I 6 out.
The collector of transistor 194 is coupled to the collector of transistor 196 and to the emitter of transistor 200. Thus, the emitter current of transistor 200 equals 11/12 I 6 out. The sum of the emitter currents of the control transistor 202 and the transistor 198 equals the collector current of transistor 192, 1/12 I 6 out. Thus, when a logic 0 is applied to the control input G2, the control transistor 202 is rendered nonconductive so that the emitter current of transistor 198 equals 1/12 I 6 out and the total output current (I 7 out) for this stage equals 12/12 I 6 out. Alternatively, with a logic 1 applied to the control input G2, the control transistor 202 is turned-on to shunt 1/12 I 6 out to the +V supply . Accordingly, the sum of the collector current of transistors 198, 200 (I 7 out) equals 11/12 I 6 out when a logic 0 is applied to the G2 input. This corresponds to a gain reduction of about 3/4 db.
The current I 7 out is fed to the next stage where it is divided according to the control bits being applied to the control inputs G1 and G0. An NPN transistor current divider circuit comprising transistors 204-220 is coupled to the control transistor 222 and is arranged to divide the current I 7 out by the fixed fraction 23/24 when a logic 1 is applied to the control input G1, thereby providing approximately 3/8 dB reduction in gain. Alternatively, the NPN transistor divider circuit provides a zero dB reduction in gain corresponding to a logic 0 being applied to the control input G1.
The same NPN transistor current divider circuit (transistors 204-220) is coupled to the control input G0 to divide the current I 7 out by the fixed fraction 47/48 corresponding to approximately 3/16 dB reduction in gain when a logic 1 is applied to the control input G0. Alternatively, a zero dB reduction in gain occurs when a logic 0 is applied to the control input G0 as will now be described.
The sum of the emitter currents of transistors 204, 206 equals I 7 out. In accordance with the relative emitter junction areas of transistors 204, 206, the respective emitter current of the same is 1/6 I 7 out and 5/6 I 7 out. The sum of the emitter currents of transistors 208, 210, 212 equals the collector current of transistor 204 (1/6 I 7 out). Accordingly, the emitter current of transistor 208 equals 2/48 I 7 out ; the emitter current of transistor 210 equals 1/48 I 7 out and the emitter current of transistor 212 equals 5/48 I 7 out. The emitter current of transistor 214 equals the collector current of transistor 206 (5/6 I 7 out). The sum of the emitter current of the control transistor 222 and transistor 216 equals the collector current of transistor 208 which is equal to 2/48 I 7 out.
The sum of the emitter currents of the control transistor 224 and transistor 218 is equal to the collector current of transistor 210 which is equal to 1/48 I 7 out. The emitter current of transistor 220 equals the collector current of transistors 212, 214 which equals 5/48 I 7 out +5/6 I 7 out or 45/48 I 7 out.
The collector current of a transistor 226 in a PNP current mirror equals the sum of the collector currents of transistors 216, 218, 220. The PNP current mirror additionally includes PNP transistors 228, 230, configured as shown, so that the collector current of transistor 230 is the mirror of the collector current of transistor 226.
A logic 0 or logic 1 control bit is applied to the control input G1 and is coupled thereby to the base of the NPN control transistor 222. When a logic 0 is applied to the base of the control transistor 222, the base emitter junction thereof is reverse biased, thereby rendering the control transistor 222 nonconductive, whereby the emitter current of transistor 216 equals the collector current of transistor 208 or 2/48 I 7 out. With a logic 0 control bit applied to the binary control input G0, the control transistor 224 is rendered nonconductive so that the emitter current of transistor 218 equals the collector current of transistor 210 or 1/48 I 7 out. Accordingly, the collector currents of the PNP current mirror transistors 226, 230 equal I 7 out when a logic 0 is applied to both the control inputs G1, G0 which corresponds to a zero dB reduction in gain.
Alternatively, when a logic 1 control bit is applied to the control input G1 the control transistor 222 is turned-on and the transistor 216 is rendered nonconductive. This reduces the output current in the transistor 230 by 1/24th, corresponding to a reduction in gain of 3/8 db. When a logic 1 is applied to the control input G0, the control transistor 224 is turned-on and the transistor 218 is rendered nonconductive. This reduces the output current in the transistor 230 by 1/48th, corresponding to a reduction in gain of 3/16 db. Accordingly, with a logic 1 applied to the control input G1 and a logic 0 applied to the control input G0, the collector current of transistor 230 equals 23/24 I 7 out, and when a logic 1 is applied to the control input G0 and a logic 0 is applied to the control input G1, the collector current of transistor 230 equals 47/48 I 7 out.
A resistor 236 and a plurality of diodes 238-248 are coupled in series between +V supply and ground, as shown, to provide a bias potential to the base of each of the NPN transistors included in the hereinbefore described current divider circuits as will now be described.
The resistor 236 is coupled to +V supply and the anode of diode 238. The anode of diode 238 additionally is coupled to the bases of transistors 170, 172, 216-220 with the cathode of diode 238 coupled to the anode of diode 240 and to the bases of transistors 92, 90, 128, 130, 166, 168, 208-214. The cathode of diode 240 is coupled to the anode of diode 242 and to the bases of transistors 84-88, 124, 126, 160, 162, 204, 206. The cathode of the diode 242 is coupled to the anode of diode 244 and to the bases of transistors 78-82, 118, 120, 156, 158, 198, 200. The cathode of the diode 244 is coupled to the anode of diode 246 and to the bases of transistors 72-76, 112-116, 150, 152, 192-196. The cathode of the diode 246 is coupled to the anode of diode 248, with the cathode of diode 248 coupled to ground.
In summary, in the digital control section a total dynamic range of approximately 95.8 dB is provided in steps equal to approximately 0.2 dB by employing nine control bits that are applied to the nine control inputs G8-G0. This is preferably achieved by progressively dividing the current I 1 supplied by the transistors 58 and 60 (FIG. 1b) in accordance with the binary input bits which control the division (or lack thereof) which occurs in the various stages of the digital control section. Consequently, the output current of the digital control section (from transistor 230) equals a predetermined fraction of the input current I 1 and corresponds to a selected logarithmic attenuation according to the binary input signal.
The collector of transistor 230 is coupled through a resistor 249 to the anode of diode 250. The cathode of the diode 250 is coupled to the collector of a transistor 251. The anode of the diode 250 additionally is coupled to the base of a transistor 252 with the emitter of transistor 252 coupled to the base of transistor 251. The diode 250 is employed to provide a voltage matching the base emitter voltage of the NPN transistor 252. The collector of the transistor 252 is coupled through the diode 107 (FIG. 1b) to +V supply . The emitter of transistor 251 is coupled to ground and the base thereof additionally is coupled to the base of transistor 253. The emitter of transistor 253 is coupled to ground, as shown. With this arrangement, the collector current of transistor 253 corresponds to the progressively divided input current I 1 according to the nine binary control bits applied to the control input G8-G0.
Referring now to FIG. 1d, there is shown a schematic diagram of a variable gain amplifier section of the logarithmic, digitally variable gain controlled amplifier according to the invention. The variable gain amplifier section is constructed in accordance with conventional integrated circuit techniques in order to provide an amplifier having a gain which is proportional to a control current being applied to a control input.
A control current, shown as I control determines the gain of the variable gain amplifier section. I control is equal to the collector current of transistor 253 which is shown in FIG. 1c. Accordingly, the gain of the variable gain amplifier section is determined by the binary control word applied to the binary control inputs G8-G0.
One should recall that the current I control is derived from the current I B (FIG. 1A) and that I B varies as a function of temperature. I control exhibits the same temperature dependence and is selected to cancel the temperature dependence associated with the variable gain amplifier, thereby to produce an amplified (or attenuated) output which is substantially independent of temperature.
An input signal, V input , is applied to the variable gain amplifier via a resistor 256 which is coupled to the base of an NPN transistor 258. The emitter of transistor 258 is coupled to the emitter of transistor 260 and the base of transistor 260 is coupled through resistors 262, 264 to the base of transistor 258, as shown. The transistors 258, 260 are configured to form a conventional differential pair.
The collectors of transistor 258, 260 are coupled to a PNP current mirror which includes transistors 266, 268 and 270 and resistors 272, 274. The output of this current mirror and the collector of transistor 260 are coupled to a load resistor 302 and to the base of an NPN transistor 276. The emitter of the transistor 276 is coupled to the base of an NPN transistor 278 with the collectors of both transistors 276, 278 coupled to +V supply to form a conventional unity gain follower which supplies the gain controlled output signal at the terminal labeled V output .
To establish bias voltages for the differential amplifier and for the unity gain follower (276,278), a string of diodes 280, 282, 284, and 286 is included and coupled to transistors 288 and 306 as shown. Operating current for these diodes is conveniently supplied by the current I REF (from FIG. 1A).
To bias the differential amplifier, an emitter follower comprising transistors 304 and 310 is coupled as shown between the junction of diodes 282 and 284 and the junction of resistors 262 and 264. The emitter of transistor 310 is coupled to the collector of a transistor 308 which operates in cooperation with the transistor 288 as a current mirror to supply current to the transistor 310. With this arrangement, transistors 258 and 260 receive an appropriate base bias and the junction of transistors 262, 264 is held at a low impedence level to provide an AC ground at that point and to provide signal isolation between the input and the output of the amplifier section.
In a similar manner, the transistors 276 and 278 receive a base bias via the illustrated connection of transistors 290, 292 between the anode of the diode 280 and the load resistor 302. Transistors 296 and 298 form a current mirror to supply emitter current to the transistor 278.
With the foregoing arrangement, the variable gain amplifier section provides an amplifier having a signal input, V input , a control input and a signal output, V output , and having a gain proportional to a control current, I control , received at the control input. The input signal, V input , is amplified by the differential pair transistors 258, 260 and the amplified signal is applied to the output terminal via the unity gain follower comprising transistors 276, 278.
The variable gain amplifier which has been described has several advantages, including the ability to provide a wide range of attenuation with a relatively small number of input bits. In the preferred embodiment, a total dynamic range of about 96 db is provided in 0.2 db steps using only 9 input bits. To perform this same function with a conventional linear attenuator would normally require 16 bits.
Further, the illustrated amplifier is designed for fabrication in integrated circuit form to provide a relatively low cost and high quality amplifier for applications such as volume controls and the like. Of course, construction in integrated circuit form is not a necessary aspect of the invention, and those skilled in the art will readily understand that other manufacturing processes may be employed. Many other changes and alterations may obviously be made by those skilled in the art without departing from the invention. Accordingly, it is intended that all such changes and alterations be considered as with the spirit and scope of the invention as defined by the appended claims.
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An integratable amplifier circuit is provided including a current generator section, a digital control section and a variable gain amplifier section. The integratable amplifier circuit is compatible with the bipolar process and can be included on an integrated circuit, such as one performing receiver and audio functions. The current generator section produces a biasing current which is applied to a digital control section which divides the biasing current according to a binary input signal to produce a control current equal to a predetermined fraction of the biasing current, corresponding to a predetermined logarithmic attenuation. The control current is applied to a control input of the variable gain amplifier section to vary the gain thereof in logarithmic steps.
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CROSS-REFERENCE TO RELATED APPLICATION
This application claims the priority of Patent Application Ser. No. 197 13 242.5 filed in Germany on Mar. 26, 1998, the subject matter of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention is based on a method of identifying a target as a friend or foe, the method comprising the following steps:
(1) An interrogator transmits a querying electromagnetic wave to a target to be identified,
(2) Provided that the target to be identified possesses a transponder matched to the querying electromagnetic wave, the target receives the querying electromagnetic wave, if necessary, and the transponder transmits an electromagnetic wave in response,
(3) The responding electromagnetic wave transmitted by the transponder is received and evaluated by the interrogator such that, if a predeterminable transponder response code is present, the associated target to be identified is classified as a friendly target.
The invention is further based on an arrangement for carrying out the method.
Particularly in the military field, but also in civilian applications, for example, for protecting large industrial sites or power stations, it is necessary to identify and/or classify targets need to be identified as friendly or threatening by using electromagnetic waves. In the Identification Friend/Foe (IFF) method, a querying transmitting/receiving arrangement (interrogator) transmits a querying electromagnetic wave, for example by means of a transmitting antenna. If the target is a friendly target, for example, a land, sea or air vehicle belonging to the same military force as the interrogator, the querying electromagnetic wave is received by a transponder on board the friendly target. The transponder then transmits a coded electromagnetic wave as a response. This wave is received and evaluated by the interrogator. The coding is used to decide whether the detected target is to be treated as a friendly target or a threatening or hostile target.
It is evident that, in particular, an interrogator can be detected, localized and attacked very early by a threatening target when the interrogator transmits the querying electromagnetic wave, especially a spatially-nondirectional wave. An obvious solution for avoiding this drawback is for the interrogator to transmit a spatially-directional, querying electromagnetic wave to a predeterminable and unknown target. This type of wave can only be received and evaluated by this target.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a method that enables a interrogator/transponder system to function reliably and which avoids detection of the interrogator and an interference of its function. It is a further object of the present invention to provide an arrangement for carrying out the method.
With the above objects in view, the present invention resides in a method in which the interrogator transmits the querying electromagnetic wave in the millimeter-wavelength range, with a predeterminable, average wavelength, a predeterminable directional characteristic, a predeterminable maximum range and a predeterminable coding, directly to the target to be identified, wherein the querying electromagnetic wave is received by the transponder by means of a receiving antenna having an essentially non-directional receiving characteristic, wherein the responding electromagnetic wave is then transmitted essentially non-directionally and lies in the same millimeter-wavelength range as the querying electromagnetic wave. The responding electromagnetic wave transmitted by the transponder is received by the interrogator by means of a receiving antenna that is directed at the target to be identified and has a predeterminable directional receiving characteristic, and in the interrogator, the received responding electromagnetic wave is supplied to a first mixer by way of a first limiter, a low-noise preamplifier and a second limiter is then converted by the first mixer and a signal generated by a local oscillator (LO), with a predeterminable frequency, into a predeterminable intermediate-frequency range, and is then demodulated in a quadrature demodulator (DEM) after a predeterminable low-pass filtering (ZFTP), resulting in orthogonal signals in the video range. The orthogonal signals are converted into an analog signal by means of a matched filter matched to the coding of the responding wave, and subsequently converted into a digital signal by means of an analog/digital converter, and the digital signal is decoded by at least a decoder and a controller and evaluated such that it is possible to identify a target as a friend or foe based on the coding,
The present invention further provides an arrangement in which essentially the same electronic assemblies are provided in the interrogator and the transponder and, with the interrogator and the transponder differ only in that the interrogator is provided with a directional transmitting/receiving antenna whereas the transponder possesses an omnidirectional transmitting/receiving antenna. In the transponder, the controller is configured so as to prevent a query mode.
One advantage of the invention is that, in the interrogator, at least the querying wave lies in the millimeter-wavelength (mmW) range. Such waves can be bundled well (spatially directed) and, furthermore, are insensitive to environmental influences, especially airborne substances such as fog, steam, smoke, rain and snow. Moreover, a predeterminable transmitting output can economically be used with millimeter waves, so a predeterminable, maximum range of the querying wave can be determined in advance.
Another advantage is that a high spatial resolution, e.g. about 100 m, is possible in a predeterminable distance range of the querying wave, for example within a range of 5 km to 10 km.
A third advantage is that a high identification probability, e.g. greater than 0.9, can be attained within a predeterminable, short time, for example within a second.
A fourth advantage is that both the interrogator and the transponder can be manufactured using mmW technology, because this allows the assemblies required by the interrogator to also be used in the transponder, resulting in the use of modular design.
A fifth advantage is that both the interrogator and the transponder can be manufactured to be spatially small and robust in an economical manner, particularly in industrial mass production, because of the mmW technology, which can be embodied in integrated technology.
A sixth advantage is that, during a self-identification process, all of the possible extrinsic queries and possible responding signals can even be processed in an electronically-disturbed environment.
A seventh advantage is that no frequency separation is necessary between the querying and responding signals. Therefore, measures that would otherwise be necessary for frequency stabilization and/or assuring long-term stability are not needed.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features and advantages of the invention will be further understood from the following detailed description of the preferred embodiments with reference to the accompanying drawing, in which the single FIGURE shows a block diagram of an arrangement is shown, which can be used for an interrogator or a transponder.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The figure shows a block diagram of an interrogator, that is, an arrangement that can transmit a coded, querying millimeter wave and evaluate a correspondingly-coded response of a transponder. The interrogator has a modular design (constructed in modules), preferably completely in semiconductor technology, for example in so-called GaAs--MMIC technology. This allows the use of low transmitting power, for example a maximum of 1 Watt, so that the range of the querying wave (transmission range) is limited to a predeterminable value. A receiver located outside of this range cannot detect the interrogator. An interrogator of this nature can be manufactured to be mechanically robust and spatially small, for example having a volume of about one liter. If a few predeterminable modules (assemblies) are changed or omitted in such an interrogator, the result is a transponder that can transmit only a responding wave coded corresponding to a predeterminable transponder identification in response to a coded querying wave (transmitted by the interrogator).
The querying and responding waves preferably lie in the same wavelength range. The associated transmitted and/or received signals lie, for example, in a frequency range of about 35 GHz to 100 GHz at a predeterminable frequency or predeterminable frequency band. At least some of the modules described below need to be adapted to the selected transmitting/receiving frequencies, for example, through a correspondingly-selected conductor technology and/or the selection of integrated semiconductor circuits matched to these frequencies.
In the interrogator shown in the figure, the coded querying wave is generated by means of a preferably digital controller Con, which is connected, on the one hand, to a likewise digital coder/decoder Cod/Dec and, on the other hand, as represented by three arrows, to an evaluation and/or indicator unit (not shown) and, if needed, to a data-processing system or a cryptographic device by way of an interface. At least one predeterminable, digital code value, which is suitable for a friend/foe target identification, is generated by means of the controller Con and the coder Cod and applied to an input of a modulator Mod. An output signal of an oscillator Osc, which generates a carrier signal having a predeterminable frequency from the mentioned frequency range of 35 GHz to 100 GHz, is applied to the other modulator input. A frequency generator having a technically-simple design and only possessing a low frequency stability can advantageously be used for the oscillator Osc. At the output of the modulator Mod, which is designed in the manner of a ring-type modulator, for example, a signal that is binary phase-modulated corresponding to the code value is formed, the signal being applied to a transmitting/receiving antenna arrangement SE, which is matched to the selected, predeterminable transmitting/receiving frequencies, by way of an analog amplifier Amp, whose amplification can be set if needed, preferably electrically.
According to another advantageous feature of the present invention the transmitting/receiving antenna arrangement SE has a directional characteristic that can readily be predetermined, that is, the arrangement is embodied as a transmitting/receiving aerial antenna. For example, a transmitted signal IS (coded query wave) having a maximum cone angle of 10° can be transmitted. A tightly-bundled transmitted signal such as this can be aimed directly at a target to be identified, for example, a land, air or water vehicle, or a person having a transponder. Because of the directional effect, this transmitted signal cannot be received and evaluated by a target that may be in the vicinity of the target, which avoids a discovery of the interrogator.
If the selected target to be identified has a transponder, as will be explained in detail below, the transponder receives the transmitted signal IS of the interrogator and subsequently transmits a transponder signal TS, which is likewise coded and modulated. This signal is preferably in the same frequency range as the transmitted signal (of the interrogator). No frequency shift is required between the transmitted and received signals, either in the interrogator or in the transponder.
If the transmitted and received signals are present in the same frequency range, self-poling is possible; in other words, in the interrogator, a portion of the transmitted signal can be coupled into the received signal due to a reflection, for example, and evaluated there in an undesired manner. This self-poling is avoidable, as will be described in detail below. The transponder signal TS is now received by the interrogator by means of the same transmitting/receiving antenna arrangement SE, that is, also by the transmitting/receiving aerial antenna.
The transponder signal TS received in the interrogator now travels via a first (amplitude) limiter BE1, which is preferably constructed from passive components, to the (antenna) preamplifier LNA having the least-possible noise. The first (amplitude) limiter BE1 is so configured that a disturbance or even destruction of the downstream (antenna) preamplifier LNA is avoided, for example by the disturbing pulses superposed over the transponder signal, the pulses having a high peak power. The output signal of the (antenna) preamplifier LNA is now supplied to a second limiter BE2. This limiter has a predeterminable number of preferably identical (band-pass limiter) channels connected in parallel. These channels permit a predeterminable (frequency) filtering of the (transponder) signal, for example, corresponding to the anticipated spectrum to be evaluated, which is a function of the selected coding (of the transponder signal).
Depending on the anticipated, different amplitudes, which are likewise a function of the coding (of the transponder signal), a different amplitude limitation is effected in the channels, if needed. This type of frequency-selective, multichannel limitation permits a suppression of the influence of interfering signals generating, for example, a broadband, interfering frequency spectrum.
The analog output signals of the (filter) channels of the second limiter BE2 are combined (added) and supplied to an input of a first mixer M1. The output signal of a local oscillator LO, which is synchronized with the oscillator Osc, is applied to the other input of the first mixer M1. An intermediate-frequency signal is generated in a predeterminable intermediate-frequency range at the output of the first mixer M1. This signal is supplied to a quadrature demodulator Dem following (an intermediate-frequency) low-pass filtering in a filter ZFTP. Orthogonal signals I, Q are generated at the quadrature-demodulator output. These signals are filtered by a matched filter MF (a filter adapted to the coding of the transmitted signals of the transponder), so that an analog signal is formed at the transponder output, the signal containing the coding of the transponder signal TS. The output signal of the matched filter MF is now digitized by an analog/digital converter A/D and evaluated by the decoder Dec and the controller Con. At the output of the controller, a yes/no signal is formed, for example, which indicates whether the detected target is to be classified as a friendly target (yes signal) or a threatening target (no signal).
In the described arrangement, the transmitted signal transmitted by the interrogator may, under unfavorable conditions, be disadvantageously coupled into its own reception antenna and be evaluated in the aforementioned manner. The result is an interfering, so-called self-poling (self-test) effect. If necessary, this can be suppressed by a suppressor circuit, which is enclosed by a dashed line in the figure, and whose function will be described below. To avoid an intrinsic query, the output signals of the oscillator Osc and the local oscillator Lo are supplied to a second mixer M2, converted there into a predeterminable frequency range through a down-conversion, and filtered by a low-pass filter ZFTP'. The resulting output signal and the output signal of the first mixer M1 are respectively supplied to an input of a further demodulator Ver, for example, a phase demodulator. At the output of the demodulator, a completely-modulated signal is formed in the video range and, then supplied to the matched filter MF and the above-described evaluation circuit. With the decoder Dec and the controller Con, a determination can be made, for example, whether a coding that is to be allocated to the transmitted signal of the interrogator is present in the output signal of the first mixer M1. This coding, which corresponds to self-poling, can, if needed, be suppressed in the further evaluation. In addition or alternatively to this, the suppressor circuit can, during a query process, advantageously check whether the process is successful.
A transponder that is part of the system differs essentially from the described interrogator in that a transmitting/receiving antenna arrangement having an omnidirectional characteristic is used; in other words, the transponder can receive from and transmit in virtually all directions. Furthermore, the transponder need only transmit a coded transponder signal TS associated with the transponder in response to a transmitted signal received and subsequently decoded by the transponder. This process is executed by the coder Cod and the controller Con, which is embodied, for example, as a digital microprocessor.
The interrogator/transponder system is Doppler-tolerant, that is, it can also be used for moved interrogators and/or transponders; the selected coding can virtually be disregarded.
Furthermore, the interrogator/transponder system makes it possible to use DBPSK (Differential Binary Phase-Shift Keying) modulation and a demodulation method matched thereto. These processes make possible a predeterminable, high system bandwidth, so that a spread-spectrum technique can be used. An advantage of this technique is that it is especially insensitive to inadvertent and/or deliberate interferences, such as so-called pulse interferences, narrow-band continuous-wave interferences and/or broadband noise interferences and fruits, garbling and/or multiple-reflection interferences.
The aforementioned high identification probability, for example greater than 0.9, that can be attained within a predeterminable, short time, such as within one second, depends on the selected coding and how often a query signal of the interrogator and/or a transponder response signal is or are repeated and evaluated.
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. For example, the transmitting/receiving antenna arrangement in the interrogator may be a mechanically-rotating arrangement, or an arrangement having an omnidirectional characteristic. Furthermore, the transmitting/receiving antennas can be separate arrangements, so that, for example, signals polarized in a predeterminable manner can be transmitted and/or received and evaluated.
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The invention relates to a system for identifying targets as a friend or foe, which is operated in the millimeter-wavelength range by means of an interrogator and a transponder, with the interrogator and the transponder having essentially the same electronic assemblies and operating in essentially the same middle transmitting and receiving frequency, and with a large frequency difference between the two being tolerable. The interrogator operates with a directional transmitting/receiving antenna, whereas the transponder possesses an omnidirectional transmitting/receiving antenna.
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BACKGROUND OF THE INVENTION
The present invention relates to the field of raw cotton fiber and cotton seed processing. In the cotton processing industry, a saw is not a device for cutting into a material, but rather it is a device that has sharply pointed teeth for grasping the cotton fibers. The early “saw” gins used discs with sharp teeth around their peripheries that resembled circular saws, which probably is how the name, “saw” originated. Later, as seed cotton (cotton before ginning) was brought to the gins containing more and more extraneous matter, including the cotton hulls, machines were developed to extract this foreign matter, and these machines became known as “extractors”.
A common element in such extractor machines is a “channel saw.” Referring to FIGS. 1 to 4 , the channel saw 11 is a thin metal strip formed into a right angle channel shape with sharp teeth 12 formed in rows 13 on the edges of the two equal legs of the channel shape. These outwardly opening channels are formed into arcs defined by the circumference of the cylinder 14 onto which the channel saws are to be peripherally mounted as shown in FIG. 2 . Thus the channel runs perpendicular to the axis of rotation of the cylinder. These channel saws are about ½″ wide between the legs and are mounted about ½″ apart axially on the surface of the extractor machine cylinder. This spacing has proven to be efficient in extracting the large foreign matter from the seed cotton locks before ginning removing the fibers from the seeds.
Recently there have been developments in roller ginning that have increased the roller gin's ginning rate to near the rate of the saw gin. The roller ginning process has been proven to break fewer fibers than saw ginning, thus to make the fiber more valuable to the textile mills. Roller ginning has largely been confined to the relatively small extra long staple cotton varieties such as Pima because of the slow, more expensive roller ginning process. With the recent ginning rate increase of roller ginning, the better quality of roller ginned cotton should open the much larger upland cotton market to roller ginning. However, while the saw ginning process can adequately control the uniformity of the fiber remaining on the seeds, the roller ginning process must depend on “seed reclaimers” to retrieve the seeds with valuable fiber left on them from the seeds that are properly ginned and send the seed with valuable fiber back for further ginning. That is to say, the reclaimer removes un-ginned and partially-ginned seeds from a seed flow and directs them to a further lint removal process.
The increase in roller ginning rate, of course, must be accompanied by an increase in the rate of seed reclaimers to be successful. While the saw extractor technology of the prior art as described above shows promise for use in seed reclaimers, the efficiency of the current standard circumferentially extending extractor saws is not adequate. The seeds leaving the reclaimers that are to be sent to the properly ginned seed bin contain too many seeds with good fiber on them and the seeds that are to be returned for further ginning have too many already well ginned seeds. It should be understood that the output of a cotton gin stand has three components: the spinnable cotton fiber (lint), which is the most valuable component; the cotton seeds from which the fiber has been removed by the ginning process, which is salable at a lower rate than the fiber; and, the trash which was entrained with the seed cotton and has been extracted. When cotton seeds with ginnable fiber still on them are discharged with the well ginned seed component, the unginned fiber is sold at the rate of the seed, or worse, the fiber lowers the seed value for the sale to the dairy industry, thereby creating an inefficiency. Likewise, when the ginned seeds are discharged with the trash, the value of the seed is lost, yielding further inefficiency. It should be understood that cotton gin plants have many seed cotton cleaners (before the ginning process) that use spiked cleaning cylinders that convey seed cotton over spaced apart grid bars or coarse screens that are sized to allow optimum trash removal without allowing full seed locks to pass through the grids or screens. When partially or fully ginned seed pass over these grids or screens, there are often too few fibers on the seeds to prevent the seeds from falling out with the trash.
It is an object of the present invention to increase the processing rate of roller ginning of upland and pima cotton. It is a further object of the invention to more efficiently return cotton seeds having recoverable fiber attached thereto to the gin stand for further ginning. It is a concomitant object to eject well ginned seeds such that they do not return to the gin nor to the trash.
These and other objects and advantages of the invention will become apparent from the following detailed description of the preferred embodiment of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
An apparatus for processing cotton seed is depicted in the accompanying drawings which form a portion of this disclosure and wherein:
FIG. 1 is a side elevation view depicting the prior art reclaimer saw.
FIG. 2 is an end view of the prior art saw shown in FIG. 1
FIG. 3 is a sectional view of the prior art reclaimer saw shown in FIG. 1 showing the profiles of typical cotton seeds.
FIG. 4 is a cross sectional view of the prior art channel saw shown in FIG. 2 showing the profile of typical cotton seed.
FIG. 5 is a side elevational view depicting an embodiment of the axially aligned saw of the current invention.
FIG. 6 is an end view of an embodiment of the present invention.
FIG. 7 is a partial sectional side elevational view of an embodiment of the present invention showing profiles of typical cotton seeds.
FIG. 8 is a partial sectional end view of the embodiment shown in FIG. 6 along with the profiles of typical cotton seeds.
FIG. 9 is a projection along line 9 - 9 of FIG. 8 showing the offset orientation of the axially aligned saw teeth.
FIG. 10 is an end view of the saw cylinder and support panel carrying the grid bars of the embodiment shown in FIG. 6 .
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the FIGS. 1-10 for a clearer understanding of the invention, it may be seen that the preferred embodiment of the invention contemplates a new saw profile and a new orientation of the saw profile.
Referring to FIGS. 3 , 4 , 7 and 8 , note the comparative views of the current standard extractor saw and the axial reclaimer saw of my invention along with the profiles of typical cotton seeds. In each figure note that a cylinder 14 or 14 ′ is mounted for driven rotation about its axis. The standard channel saw presents parallel rows 13 of teeth 12 extending around cylinder 14 and spaced about ½ inch apart. The rows 13 cannot be much closer because screw head 16 is seated with in the channel to attach the saw to cylinder 14 . In FIGS. 5 to 8 , note that the illustrated embodiment of the present invention utilizes channel saws 11 ′ with rows 22 of teeth 23 affixed to the cylinder 14 ′ and extending axially along the outer surface of cylinder 14 ′.
The efficiency of the reclaimer process is dependent upon the certainty of the reclaimer saws grasping and holding the seeds with valuable fiber attached while centrifugal forces and grid bars 44 around the reclaimer cylinders are efficiently designed to expel the seeds without significant amounts of valuable fiber attached. FIGS. 3 and 7 most clearly illustrate the comparative certainty of a seed being grasped and held by the standard extractor saw as compared to the axial reclaimer saw of my invention. The roller gin process often strips only one side of a seed S, leaving a profile of less than ½″, that is to say, a profile less than the spacing between the prior art saws. It also should be understood that in the conventional extractor process the seeds are applied to the extractor saw teeth by stationary brushes 17 with bristles 18 about 3″ long that comb the fibers straight back, parallel to the saw movement. Thus, the conventional extractor saw teeth may not contact the fibers of some seeds with valuable fiber, let alone firmly grasp the fibers.
By contrast the teeth 23 of my axial channel saw may be made as close to each other axially as desired. Furthermore the teeth 23 of the of the two rows 22 formed by the channel may be offset axially to further increase the certainty of grasping the valuable fibers or increasing the grip of the combined teeth to allow more vigorous centrifugal forces and grid bar 44 designs to eject the seeds that are already properly ginned.
The significance of the different actions of the two saw structures needs to be fully understood. Significantly, the seed rotation with the reclaimer saw cylinder is caused primarily by the saw teeth grasping the fibers attached to the seeds, however some seeds are just entrained with seeds that are impaled on the saw teeth, thus these entrained seed are not grasped by the saw teeth. Some of the seeds being presented to the reclaimer saw teeth are already adequately ginned and therefore must depend upon being entrained by the seeds impaled on the saw teeth or to a lesser extent, the paddle effect of the bare saws themselves as these seeds don't have enough long fiber to be grasped by the teeth. These seeds are free to properly be ejected by centrifugal force and grid bar action unless they are entrapped under seeds that are impaled on the saw teeth. Here the advantage of the axial reclaimer saw becomes apparent. Whereas the current extractor saws with their ½″ axial spacing have at best only three teeth 12 per inch axially to grasp and hold the seeds with long fibers, my axial channel reclaimer saw can have as many teeth 23 axially as is practical to punch, say eight or ten per inch per leg of the axial channel. The axial channel has two legs spaced a little over ½″ apart which may be offset axially one half a tooth space to offer sixteen or twenty teeth axially to grasp the long fibers for every angular saw cylinder surface movement of a little over one inch. The channels may be spaced apart on the cylinder surface by ½″ for uniform spacing of the legs of the channels, or the separation may be varied. As may be seen in FIGS. 5 to 8 of the present embodiment the leg of the channel and the teeth formed there on preferentially extend at an acute angle from the tangent line at the surface of the drum, such that the teeth are angled toward the direction of rotation. Preferably the legs and corresponding teeth are inclined toward the direction of rotation of the saw cylinder at an angle of about 60 degrees from a line normal to the surface of said cylinder. The teeth may be inclined at about 35 degrees from the tangent line of the cylinder, thus, an appropriate range would be about 30 to 35 degrees from the tangent line of the surface of the cylinder.
The stationary brush 17 extends axially from end to end of the seed reclaimer machine and has very uniform bristles 18 . The bristles 18 uniformly press the axially randomly located seed with attached fiber onto the saw teeth or spaces axially between the teeth without moving the seed axially, but perhaps combing the fibers on the seeds back into the spaces behind the seeds. In an alternative embodiment, the use of more than one stationary brush in series further increases the likelihood of the saw teeth grasping or more firmly holding the seeds with long fibers attached. A second or third stationary brush could physically “roll back” seeds not already firmly grasped, to the next axial row of teeth. Mounting surfaces in the housing are used to mount two and even three stationary brush sticks at thirty to forty-five degrees from tangent to the saw surface just ahead of the first grid bar. This inexpensive addition could help assure that the seeds with significant long fibers attached are firmly impaled on the reclaimer saw teeth and help insure that the seeds with insignificant amounts of long fiber are brushed free of the seeds impaled on the reclaimer teeth and swept free of the reclaimer teeth themselves. Also the additional combing action of the added stationary brushes potentially would free the well ginned seed entrapped under the seeds with fibers attached clinging to the saw teeth or uncover the well ginned seed trapped in an uneven surge of seeds, thus making the well ginned seed free to move outward by centrifugal force.
Since the seeds present profiles from about 3/16″ to ⅜″ wide, the prior art reclaimer saws will grasp almost 100% of the seeds with fibers attached which are aligned with a circumferential row 13 of teeth, and fewer of the seeds that are aligned with the spaces (½″ wide) between the rows 13 . Even the seeds aligned with the saw teeth will have only a narrow band of fibers grasped by the saw teeth because the teeth 12 are aligned in a row 13 with no significant extension parallel the axis of rotation.
By contrast the reclaimer saws of my axial channels have axially closely spaced teeth 23 as shown in FIGS. 5 , 7 & 9 that virtually eliminate the variation in likelihood the teeth 23 will grasp the fibers. Furthermore the axially closely spaced teeth 23 of my axial channels will grasp a wide band of fibers, at least the width of the seed profile, that the stationary brushes 17 press onto the saw teeth. Accordingly the teeth 23 not only uniformly grasp the seed with fiber attached, but the embodiment greatly increases the number of teeth 23 holding the seed to allow use of more vigorous forces to eject the well ginned seed without losing seed needing further ginning. The angular (peripheral) tooth spacing of my axial channel is greater than that of the current extractor channel and furthermore, my axial channel saws may be mounted farther apart peripherally. Neither structure should have a problem with processing rate, but there is a large difference in the firmness of the grip of the teeth holding the seed with fibers attached. The somewhat wider angular spacing of the axial rows of teeth of my axial channels along with the variable peripheral spacing of the axial channels may be helpful in freeing the well ginned seed that may be entrapped under the seeds with long fiber attached that are clinging to the axial rows 22 of teeth 23 . My axial channel, with its superior fiber grip, should be accompanied with faster reclaimer cylinder rotational speeds to increase the centrifugal forces needed to eject the properly ginned seed. This, of course, should also increase the potential processing rate.
Further, as shown in FIG. 10 , the reclaimer of the proposed embodiment uses new grid bars 44 of an improved design. Specifically, prior art grid bars were generally tubular having a round cross-section. The new grid bars 44 are substantially triangular with a linear surface 46 proximal and spaced from the line of travel of the tips of teeth 23 such that the linear surface 46 extends substantially along a plane that would be parallel to the tangent plane of the teeth on the cylinder. Therefore the line of travel of the teeth 23 diverges from the linear surface such that cotton seed which does not have fiber grasped by the teeth 23 nor entrained with the fiber from other seed is ejected without interference from the surface in the interstices between grid bars. The number of grid bars and their spacing is empirically dependant upon rotational speed and the quantity and length of cotton fibers remaining on the reclaimed seed. The apex of the grid bars 44 will be rounded sufficiently to avoid damaging seed as it passes between the grid bars and the cylinder.
It is to be understood that the form of the invention shown is a preferred embodiment thereof and that various changes and modifications may be made therein without departing from the spirit of the invention or scope as defined in the following claims.
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A reclaimer cylinder for use in reclaiming cotton seeds containing spinnable lint from partially ginned cotton seeds utilizes channel saws mounted axially on a cylindrical body with axially closely spaced teeth that virtually eliminate the variation in likelihood the teeth will fail to grasp the fibers present on such cotton seeds. Triangular grid bars facilitate removal of fully ginned seeds that are not entrained in fibers of other seeds.
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BACKGROUND OF THE INVENTION
This invention relates to apparatus for fusing together electric conductors, and more particularly to apparatus for fusing coil leads to tangs or slots of electric motor armature commutators.
Electric motor parts such as armatures have coils of wire and heavier metal parts (e.g., commutators) to which leads from the coils must be electrically and mechanically connected. A technique which is frequently used for making these mechanical and electrical connections is known as fusing. This technique involves the application of heat and pressure from a fusing electrode to the two elements to be joined (e.g., the commutator and the coil lead) in such a way that these two elements are pressed into firm and intimate contact with one another, and at least one element (e.g., the commutator) is permanently deformed to hold the two elements together. For example, a coil lead wrapped around a commutator tang may be fused to the commutator by deforming the tang down into intimate contact with the lead. Alternatively, a coil lead in a commutator slot may be fused to the commutator by partly crushing the slot in order to close it around the lead. The heat required for the fusing process is typically generated by passing an electric current through the fusing electrode and the elements to be fused and into a ground electrode which contacts another part of the workpiece. The fusing electrode (typically made of tungsten) is the highest resistance element in this circuit and is therefore the element which is heated by this current. Heat flows from the electrode into the elements being fused.
The tip of the fusing electrode which contacts the elements being fused is subject to considerable mechanical, thermal, and even electrical stress. Accordingly, these tips wear quite rapidly and must be changed fairly frequently. European patent application 201,112 shows fusing apparatus in which several fusing electrodes are mounted on a turret which both reciprocates (to perform fusing operations) and rotates (to bring a new fusing electrode into operative position when the preceding electrode is worn). When all the electrodes on a turret are worn, the turret can be removed and either replaced with a new turret or the old turret put back on with the electrodes either replaced or resharpened.
The machine shown in the above-mentioned European application has fairly simple control of the fusing cycle. More recent developments in this technology provide more sophisticated fusing cycle control such as closed loop control based on the displacement of the fusing electrode and/or the force applied by the electrode. Such more sophisticated control is shown, for example, in commonly assigned, U.S. Pat. No. 5,063,279, and hereby incorporated by reference herein. While it would be desirable to apply these more sophisticated control techniques to fusing machines having rotating turrets for electrode replacement, there are several respects in which the known rotating turret machines are not especially well suited to such control. For example, the heavier the moving elements are, the more difficult it is to achieve accurate and precise closed loop force and/or displacement control. The more massive the controlled elements, the more serious a problem vibration and inertia become. The known rotating turret fusing machines have relatively heavy moving parts and are therefore not ideally suited to more sophisticated control.
As another example of the respects in which known rotating turret fusing machines do not lend themselves particularly well to more sophisticated control, the known machines typically have only a single rest position of the moving elements. This is the position from which each fusing cycle starts, as well as the position in which the turret is rotated or removed. Accordingly, this rest position must be fairly far from the armature or other workpiece being fused so that the turret can be rotated or removed without risk of damage to the armature. If the machine is intended for fusing armatures of different diameters, the largest armature diameter determines the acceptable rest position. Accordingly, the rest position may have to be quite far from the fusing position for many or even all of the armatures to be fused. This lengthens the fusing cycle stroke, wastes time, and reduces the production rate of the machine. These disadvantages may be especially significant when employing closed loop force and/or displacement control because with such control the fusing head may have to move more slowly in order to allow time for analysis and use of the feedback signal. Accordingly, the shortest possible fusing cycle stroke is generally preferable with closed loop control. Closed loop control may also benefit from having fusing cycle strokes of uniform length regardless of the size of the workpieces being fused. This may reduce or substantially eliminate the cycle control reprogramming that would otherwise be required when adapting the machine to fuse workpieces of different sizes.
In view of the foregoing, it is an object of this invention to provide improved machines for fusing electric motor parts.
It is a more particular object of this invention to provide fusing machines, especially (but not necessarily) of the type having a rotating turret holding several fusing electrodes, which are better adapted to more sophisticated control such as closed loop force and/or displacement control.
It is another more particular object of this invention to provide fusing machines having a fusing stroke of constant length regardless of such factors as deviations or changes in the dimensions of the parts being fused.
It is yet another more particular object of this invention to provide fusing machines with less massive moving parts and which lend themselves to the use of shorter fusing cycle strokes.
SUMMARY OF THE INVENTION
These and other objects of the invention are accomplished in accordance with the principles of this invention by providing a fusing machine in which the movement of the fusing head is positively controlled at all times so that the fusing cycle stroke can start from any desired position relative to the workpiece, and so that the fusing head can be moved farther from the workpiece when it is necessary to change the electrode. This allows the fusing cycle starting position to be relatively close to the workpiece and to be adjusted for changes or deviations in the workpiece. The length of the fusing cycle stroke can thereby be made constant for all workpieces if desired. The machine may measure a dimension of a workpiece to be fused in order to determine the fusing stroke starting point from that measurement. In the case of fusing machines with rotating turrets, the weight of the moving parts of the machine is reduced in accordance with the invention by mounting the actuator which reciprocates those parts on the frame of the machine, and by deriving the motion required to rotate the turret from the reciprocating motion rather than from a separate actuator.
Further features of the invention, its nature and various advantages, will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial elevational sectional view of an illustrative embodiment of a fusing machine constructed in accordance with the principles of this invention. FIG. 1 is taken generally along the line 1-1 in FIG. 2, although additional elements are shown in FIG. 1. In The vicinity of the uppermost electrode 11, the alignment of section 1-1 is shifted slightly to one side in FIG. 2 so that representative bolts 15 will be shown in FIG. 1.
FIG. 2 is a partial elevational sectional view taken along the line 2-2 in FIG. 1.
FIG. 3 is a partial plan view, partly in section, taken along the line 3-3 in FIG. 1.
FIG. 4 is a partial elevational sectional view taken along the line 4-4 in FIG. 3.
FIG. 5 is an upward continuation of FIG. 1.
FIG. 6 is a partial elevational sectional view taken along the line 6-6 in FIG. 2.
FIG. 7 is a partial elevational view taken in the direction 7 in FIG. 1.
FIG. 8 is a partial plan view, partly in section, taken along the line 8-8 in FIG. 7.
FIG. 9 is a partial elevational sectional view showing a leftward extension of the lower part of FIG. 1.
FIG. 10 is a more detailed block diagram of a portion of FIG. 5.
FIG. 11 is a flow chart of illustrative operations which can be carried out in the apparatus of this invention.
FIG. 12 is a flow chart of an alternative to FIG. 11.
FIG. 13 is a partial elevational sectional view of an alternative type of workpiece which can be processed in the apparatus of this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Although the invention is described herein in the context of fusing machines with multiple fusing electrodes on a rotating turret, it will be understood that many of the features of the invention are equally applicable to other types of fusing machines such as those with only a single fusing electrode and no rotation of a turret to automatically replace the electrode.
In the machine shown in the drawings, a certain number of electrodes 11 are carried by a turret 10. Each electrode 11 is fixed to turret 10 by means of a removable clamping block 12 which has a part-cylindrical seat 13 for receiving a portion of the electrode's external surface. A mating part-cylindrical seat 14 of turret 10 confronts the seat of the clamping block in order to receive another portion of the electrode's external surface. By tightening bolts 15 the electrode can be firmly fixed between the clamping block and the turret. An adjustment screw 16, threadedly engaged in a bore aligned and communicating with the space between part-cylindrical seats 13 and 14, can engage the end of electrode 11 and acts as a reference surface in order to position the electrode in relation to the center of the turret defined by axis 37.
In order to obtain satisfactory fusing (i.e., fusing in required time with no overheating of the parts to be fused), attachment of the electrode to the turret must present low electrical resistance to passage of the current required to fuse. This can be accomplished by having an electrode of prismatic form which is received against precisely machined electrode seats of turret 10 so that a considerable surface of such an electrode can be in contact with turret 10 in order to reduce the electrical resistance for the passage of current. If using an electrode which has a cylindrical form for contacting turret 10, then precisely machined seats for receiving the electrodes and an elastically deformable clamp connection as shown in FIG. 1 are appropriate for guaranteeing that sufficient electrode surface is in firm contact with the turret.
The tip portion of the electrode having the surface which comes into contact with parts to be fused (e.g., the top surface of depicted commutator tang 19 around which one or more coil leads 19" are looped, or alternatively a commutator ridge having a slot containing coil leads) is usually made of tungsten material. This portion of the electrode has a well known prismatic configuration which presents a contact surface having dimensions and inclination based on the parts to be fused.
Electrode 11, required to carry out the fusing operation, translates along axis 42 from rest position 17 in order to contact parts 19 to be fused (in the embodiment of FIG. i, the tangs of an armature commutator). After a fusing operation, electrode 11 translates back to starting position 17. The armature is then rotated about axis 117 to position another tang 19 for fusing, and the fusing cycle is repeated. Rest position 17 is preferably relatively close to the workpiece to keep the fusing cycles as short as possible. In order to fuse correctly, low electrical resistance should be guaranteed all along the path provided for passage of the electric current. In particular, all the connections between dismountable parts should present low electrical resistance. In the embodiment of FIG. 1, one factor in achieving low electrical resistance is the contact of the large external surface of shaft 20 with its support, and also a firm contact between turret 10 and shaft 20 at face 27. Fusing cycles are preferably accomplished using closed loop control of the electrode displacement and/or using closed loop control of the electrode force, either of which is obtained by means of programmable controls. Further information regarding the way the fusing cycle is preferably accomplished is found in the above-mentioned patent application Ser. No. 436,633.
Turret 10 is releasably connected to shaft 20 by engaging hollow protrusions 21 of the shaft with the seat 22 of the turret. Screw 23 having handle 24 passes through turret 10 and also through hollow protrusions 21 to engage threaded bore 25 of shaft 20. Once turret 10 has been mounted by engaging hollow protrusions 21 of the shaft with seat 22 of the turret, handle 24 can be turned to cause screw 23 to thread into bore 25, thereby causing the handle face to abut and press against front face 26 of the turret. Further turning of handle 24 causes seat 22 of the turret to move along hollow protrusions 21 until a back face 27 of the turret comes into abutment with an opposite shoulder 20' of shaft 20. A final forced turning of handle 24 generates a sufficient friction reaction between back face 27 of the turret and opposite shoulder 20' of shaft 20 to impede rotation and translation of turret 10 in relation to shaft 20. Such an operation to mount turret 10 is carried out with the electrode contact surface positioned at level 18 in relation to the workpiece to be fused. Position 18 is preferably more remote from the workpiece than fusing cycle start position 17.
To achieve the desired control performance with the required precision, the assembly which carries the turret should be rigidly connected to the members which impart translation to it and which also generate the force required by the electrode to fuse. The assembly which carries turret 10 should not carry unnecessary loads. More precisely, the assembly which carries turret 10 should be light in order to obtain high translation speeds so that the cycle time will be reduced to a minimum, especially when the abovedescribed closed loop force or displacement controls are used. To obtain these characteristics, actuators such as those provided for obtaining translation, rotation, and locking of the turret have not been mounted on the moving part of the apparatus. Instead, these elements are mounted on the stationary frame of the machine to the greatest extent possible.
Hollow protrusions 21 of shaft 20 are preferably split so that they deform elastically during the described operation to connect turret 10 to shaft 20. Shaft 20 is slideably mounted in bore 29 of support block 28. Gear wheel 30 is connected to an end face of shaft 20 by means of bolts 31. Disk spring or belleville washer 32 is interposed between the inside face of gear 30 and the rear end of support block 28. By tightening bolts 31, spring 32 can be preloaded in order to guarantee that rear face 33 of shaft shoulder 20' is pulled toward the front face of support block 28. Steel annular ring 34 is interposed between shoulder 20' and support block 28, and acts as a running surface when shaft 20 rotates in relation to support block 28. Without the use of such a ring 34, these members would run directly on each other, and might wear out too quickly. Gear 30 has key protuberance 35 which is received in a seat 35' machined in a rear face of shaft 20. A precisely machined block or tablet 36 is fixed to shaft shoulder 20' by means of a bolt. The angular position of tablet 36 around axis 37 of the mounted turret 10 is such that after engagement in a mating way in turret 10, electrodes 11 will be precisely phased in relation to the teeth of gear 30.
Electric current is transmitted to electrodes 11 through supply cable 38 permanently connected to support block 28 by means of a bolt connection 38'.
The parts which hold the electrode and which transmit electric current to it should be maintained at temperatures which do not exceed predetermined limits so that parts to be fused do not become overheated. Precautions to maintain such temperatures within certain limits are required even after current passage has terminated and when the electrode is still in contact with the parts to be fused. At this stage, the heat which could accumulate in the parts holding the electrode should not contribute to further heating of those which must be fused.
To avoid this, the parts which transmit electric current to the electrode should dissipate the heat which they tend to accumulate at extremely rapid rates. This can be accomplished by making such parts of copper material which dissipates heat at high rates and also conducts electric current efficiently. Accordingly, shaft 20 and support block 28 are preferably made of copper alloy material. Furthermore, heat dissipation can be increased by providing the parts which hold the electrode with their external surfaces having extensive exposure to the surrounding environment which is at room temperature.
Cooling of these parts can also be accomplished by circulating coolant or refrigerant fluid in their internal structure. In the embodiment of FIG. 1, shaft 20 is provided with grooves 25' communicating with fluid supply fittings (not shown) in support block 28. Seals 25" seated in shaft 20 and engaged with supporting block 28 form a sealed compartment for allowing fluid circulation through grooves 25'. Fluid circulating through channels 25' can pass through bores in shaft 20 and then through mating orifices (not shown) in face 27 in order to circulate in passages of turret 10. Such fluid passages are emptied by means of automatic discharging means prior to dismounting the turret from the shaft. This fluid circulation cools shaft 20, support block 28, and turret 10 during fusing.
Support block 28 is carried by translating member 39 made of aluminum alloy material. Connection between these two members is achieved by means of flange connection 40 using bolts 41.
In order to cause the operative electrode to move and fuse along axis 42, translating member 39 is guided and translated by advancement assembly 43 shown in FIG. 5. In such an assembly, translating member 39 is connected to the end of a conventional ball bearing screw or recirculating ballscrew 120 by means of flange connection 121. Ball recirculating sleeve or nut assembly 122 engages screw 120'. Sleeve 122 is carried by bell structure 123 and connected to this member by means of flange connection 124. Bell structure 123 is supported on bearings 125 so that it can rotate about axis 126. Gear 127 is flanged to the top end of bell structure 123. Gear 127 engages an aligned gear 128 connected to output shaft 132 of DC motor 131. By rotation of DC motor 131, sleeve 122 can be caused to rotate in order to translate screw 120' along axis 126. This causes the electrode 11 aligned with fusing axis 42 to translate along that axis. DC motor 131 is provided with a speed sensor and an encoder connected via leads 46 and 47 to appropriate controls 48 so that it can be controlled in closed feedback to guarantee programmed torque and speed output. In this way the electrode which fuses along axis 42 can be caused to operate with programmed speed values and programmed force values. The position of the electrode is positively controlled at all times. A conventional type of load sensor (not shown) can be mounted between the translating member 39 and support block 28 (FIG. 1) and connected to controls 48 (FIG. 5) via lead 49 to monitor the force experienced by electrode 11 during the fusing cycles in order to obtain further closed loop performance as described above. As another example, displacement of the electrode 11 currently being used for fusing can be monitored by connecting a conventional type of linear displacement potentiometer (not shown) between support block 28 and the fixed frame of the machine, and by applying the output of this potentiometer to controls 48 via lead 49'. This linear potentiometer may be used in place of an encoder associated with motor 131 as described above, or in addition to such an encoder so that controls 48 can detect play which may eventually develop in the mechanism which reciprocates fusing electrodes 11. Slide 129 (FIG. 5), connected to translating member 39, engages a guide 130 of the machine frame. Such a connection is required to avoid rotation of translating member 39 about axis 126 due to the tendency of screw 120' to turn.
To prevent turret 10 from rotating in relation to support block 28 during fusing operations, an arm 50 is hinged to support block 28 by means of a swivel pin 51 which has its ends supported in bores 52 of support block 28. The internal part-cylindrical surface 53 of arm 50 is biased against a portion of the outside surface of shaft 20. In order to avoid rotation of the shaft, precompressed spring 54 (FIG. 2) mounted in a seat of translating member 39 pushes on an end of arm 50 to generate a locking friction reaction between part-cylindrical surface 53 of arm 50 and the external surface of the shaft. Cursor 55 is slideably mounted in a bore aligned with the seat of spring 54. An anti-wear ball contact member 56 is seated in a front end of cursor 55 in order to engage arm 50. An idle wheel 57 is fixed to the other end of cursor 55 in order to engage a lever 58 hinged to the machine frame. Cursor 55 can slide to engage arm 50, but it cannot rotate because antirotation pin 59, fixed to the translating member 39, is engaged in a way formed in cursor 55. Lever 58 is hinged to the machine frame by means of pin 62 (FIG. 3), so that it can rotate in a plane positioned at a certain level above and parallel to the workpiece supporting table. One end of lever 58 is connected to the rod of pneumatic cylinder 60. The other end of lever 58 carries a rack mechanism 61 for engaging gear 30 fixed to shaft 20. Abutment surface 69 is also provided on this end of the lever to engage idle wheel 57 of cursor 55.
Rack mechanism 61 consists of support pins 63 (FIG. 4) slideably mounted in bores of lever 58. Rack 64 is carried by support pins 63. Spring 65, seated between support pins 63, biases rack 64 toward gear 30. When gear 30 is not aligned with rack 64, ledge 66 of rack 64 abuts against a ridge (not shown) of lever 58 to limit the excursion of the rack's movement under the biasing action of spring 65. In this way, rack 64 is capable of accomplishing a lost motion when it is caused to engage the gear.
By actuating pneumatic cylinder 60 (which is also mounted to the frame of the machine as shown in FIG. 3), lever 58 can be rotated about pin 62 to cause abutment surface 69 to engage and push cursor 55, and also to cause engagement of rack 64 with gear 30. The rod of pneumatic cylinder 60 moves until lever 58 comes into contact with adjustable stop 68. At the end of such a movement, cursor 55 will have translated to release the locking action which arm 50 has on shaft 20. Furthermore, at the end of such a movement, rack 64 will, as a result, be engaged with previously aligned gear 30.
Once this has occurred (signalled by a position sensor, not shown), the advancement assembly of FIG. 5 translates supporting block 28 along a path having a predetermined length in direction 140 (FIG. 1) so that gear 30 is turned by being engaged with stationary rack 64. In other words, the motion required to rotate turret 10 is derived from a linear motion of the turret support. The length of the motion in direction 140 is chosen to cause shaft 20 and therefore turret 10 to rotate by an angular increment which positions an adjacent and new electrode 11 into alignment with the workpiece to be fused on axis 42. During the above-mentioned translation, idle wheel 57 of cursor 55 runs on abutment surface 69 to maintain shaft 20 unlocked. This motion in direction 140 is preferably carried out using closed loop position control (e.g., making use of the output of the motor encoder or linear displacement potentiometer and controls 48 described above in connection with FIG. 5).
Important functioning features of the machine, such as those listed in the following, can be obtained by means of a programmable position control 48 of the actuator required to translate the assembly carrying the turret, or more precisely, by having such an assembly which is capable of assuming variable and programmable position.
When a workpiece must be fused, the electrode contact surface is advanced by assembly 43 (FIG. 5) along axis 42 (FIG. 1) starting from a known rest position 17. During such an advancement, electrode 11 comes into contact with the workpiece and continues to advance, thereby deforming the parts to be fused. In the preferred embodiment, controlled deformation of each commutator tang 19 requires that the tang, together with the wire beneath the tang, are deformed to predetermined final conditions (predetermined diameter variation of the wire under the tang and predetermined reduction in thickness of the tang). If this does not occur (e.g., the wire and tang are deformed in excess of the required specifications), the resulting connection will be weak and therefore subject to breaking during functioning of the final motor. If the deformation is not sufficient, the connection will not have the correct electrical properties and/or may not be maintained during functioning of the final motor. Furthermore, the commutator bars having the tangs to be fused may be located with a certain eccentricity in relation to the longitudinal axis of the armature. Particularly for thin wires, controlled deformation of the tang must take place with respect to the actual level of the commutator bar. Otherwise the final deformation of the tang and the wire can be influenced by the eccentricity that has previously been mentioned. To obtain correct results in a situation of this type, the eccentricity of the commutator bar having the tang to be fused can be measured by means of a movable contact sensor 45 (FIG. 1) or alternatively a conventional type of optical sensor (not shown). Such a measurement can be carried out prior to advancing the electrode 11 which fuses the tang or during the actual fusing operation. The sensor measures the distance of the commutator bar from an absolute reference. This information is then supplied via lead 44 to the controls 48 of the machine so that operations involving controlled displacement of the electrode are carried out referring to the actual position of the commutator bar having the tang to be fused. For example, contact sensor 45 can be mounted on the frame of the machine and momentarily lowered into contact with the surface of the commutator to be fused in order to produce an output indicative of the location of that surface. This output can be used in any of several ways. For example, it can be used to measure the overall size (radius or diameter) of the commutator in order to enable the controls of the machine to establish fusing cycle rest position 17 at a predetermined distance from the workpiece. This can be done relatively infrequently (e.g., whenever a new armature size or type is to be processed) or more frequently (e.g., before every fusing cycle or before closely spaced fusing cycles in order to measure possible eccentricity or other deviations of the commutator surfaces). Fusing cycle starting position 17 may be relocated on the basis of this measurement (e.g., in order to keep all fusing cycle strokes of approximately the same length), or the fusing cycle may otherwise be modified in accordance with this measurement. Further description of the fusing cycle which includes heating of the parts to accomplish the required final fused condition will be found in above-mentioned U.S. Pat. No. 5,063,279.
FIG. 10 shows programmable control 48 in more detail. The basic program is initially received via lead 48a and stored in memory 48b. Central processing unit ("CPU") 48c performs this program with additional inputs received as described above via leads 44, 46, 47, 49, and/or 49'. These inputs are both data for the program and may also be used by CPU 48c to modify the program. As a result of performance of the program, CPU 48c supplies a reference signal to motor drive 48d. This reference signal corresponds to the position which electrode 11 must reach in required timing along axis 42. Motor drive 48d operates motor 131 in accordance with this reference signal. CPU 48c may also compare this reference signal to the signal coming (via lead 47) from the encoder associated with motor 131. This encoder output signal is indicative of the actual position of electrode 11 along axis 42. For example, when the reference signal corresponding to rest position 17 (or any other position which the electrode must reach) is equal to the one coming from the encoder (or differs from the encoder signed by less than a predetermined tolerance) motor 131 is caused to stop to hold electrode 11 in the required position. Information relative to the required position which the electrode should reach during the various phases of the fusing cycle (i.e., the above-described "program") is input via lead 48a and stored in memory 48b. This stored information is used by CPU 48c as described above to generate appropriate position reference signals during the various phases of the fusing cycle.
Of interest to this invention is that during the fusing operation the displacement of electrode 11 in relation to the workpiece and also the force which electrode 11 applies to the workpiece are preferably continuously monitored and controlled, starting from rest position 17. Position 17 should be at a small distance from the workpiece to avoid having to accomplish long advancement paths which are a waste of machine time. By means of programmable control 48, position 17 can be changed each time an armature with a different commutator diameter needs to be processed. Turret 10 may have to be removed and substituted when the electrode tip is in such a position, which would require removing the armature before dismounting the turret. To avoid having to remove the armature, it is preferable to translate the turret by means of programmable controls so that the electrode tip is positioned at a greater distance from the armature (e.g., at position 18). In this way, the electrode can be caused to assume predetermined positions along axis 42, and also to apply predetermined forces on the workpiece as described in above-mentioned U.S. Pat. No. 5,063,279.
When turret 10 has to be rotated to present a new electrode on axis 42, starting from the electrode in rest position 17, assembly 43 moves translating member 39 in direction 140 by means of closed loop displacement control until gear 30 is aligned with rack 64. This position is typically farther away from the workpiece than rest position 17. When this position is reached, cylinder 60 (FIG. 3) is actuated to engage rack 64 with gear 30 and to release arm 50, as has been described above. Once this has occurred, advancement assembly 43 moves translating member 39 by means of closed loop displacement control 48 for a predetermined distance (typically still farther in direction 140), which causes gear 30 to turn in relation to rack 64 until the new electrode becomes aligned on axis 42. Cylinder 60 (FIG. 3) is then depressurized so that spring 67 (FIGS. 3 and 4) biases lever 58 to cause disengagement between rack 64 and gear 30. This also causes disengagement between abutment surface 69 of lever 58 and idle wheel 57 of cursor 55. In this way, arm 50 will be biased by spring 54 to safely lock shaft 20.
A counter, together with the controls 48 of the fusing machine, determines when all the electrodes of turret 10 have been used. When such a situation is reached, an alarm is activated to warn the operator that the turret must be replaced. Another turret having sharpened and properly configured electrodes can then be mounted on the machine.
To remove turret 10 from the machine, spring biased pin 70 (FIGS. 1 and 6) is pushed by the operator in aligned bores 71 of turret 10. At the same time, the operator turns handle 24 in order to release turret 10 from shaft 20. Once screw 23, connected to handle 24, is completely disengaged from bore 25, turret 10 can be removed by simply pulling it along axis 37.
Sharpening of electrodes 11 removes material from their tips and configures them to a required shape. Once such an operation has been carried out, electrodes 11 are fixed to the dismounted turret 10 by using a fixture together with adjustment screw 16 to position them at the same distance from the center of turret 10. Usually such a fixture holds the turret center at a precise distance from a reference plane. Once electrodes 11 have been sharpened, they are mounted on turret 10 by bringing them into abutment with such a reference plane to guarantee that their contact surface is at a predetermined distance from the turret center. Adjustment screw 16 maintains electrode 11 against the reference surface.
After the foregoing operations to fix electrodes 11 to turret 10, it may still occur that the distance between electrodes 11 and the turret center is not the same as the one existing on another turret which has been previously mounted on the machine. For example, the above-described fixture technique may not be sufficiently precise, especially for situations requiring extremely narrow tolerances in the final deformation of the fused parts. Or a less precise method than the above-described fixture method may be used, with the result that relatively large electrode positioning errors occur. Or, as still another possibility, an electrode may shift after it has been used, or play may have developed in the electrode reciprocating direction. Any of these possibilities may make it important for the machine of this invention to include the ability (as will now be described) to precisely determine the location of the tip of a new electrode mounted on the machine.
As has already been mentioned, the electrode's advancement along axis 42 in order to carry out the fusing operation preferably always start from the same rest position 17 of the machine. To place the electrode contact surface in such a position when its distance from the turret center has changed, the newly mounted turret is moved under displacement monitoring and displacement control starting from a known position such as the position of the turret when turrets are substituted until the electrode comes into contact with a reference surface positioned at a known distance from fixed work table surface 111 along axis 42. For example, reference surface 18' (FIG. 1) may be on the opposite side of the turret from the workpiece, and the turret may be raised from the turret replacement position until the upward pointing electrode contacts that surface in order to measure the distance from the center of the turret to the tip of the electrode. In contacting this reference surface, the electrode experiences a sharp change of force which is monitored by the controls of the machine. Such a change of force is experienced for a monitored displacement. By simple calculation carried out by the controls 48 of the machine, the unknown distance between the electrode contact surface and the center of turret 10 can be found. This can be done each time the turret is turned to substitute an electrode, or it can be carried out for all electrodes before a new turret starts fusing. The information relating to the position of the electrode is stored in the machine controls so that the measurement pertaining to a particular electrode can be used when that electrode is employed for fusing. In particular, the position information for each electrode is used to bring the electrode contact surface into the position corresponding to the machine's rest position 17 by actuating assembly 43 using closed loop displacement control.
FIGS. 11 and 12 show alternate ways in which closed loop force and/or displacement controls can be used in accordance with this invention to measure the actual location of an electrode tip. The steps shown in each of these FIGS. are performed by machine controls 48 (FIG. 5). In FIG. 11, for example, the first step 202 is to start reciprocation of the turret toward a reference surface such as surface 18' in FIG. 1 under closed loop force control. The resulting displacement is monitored in step 204. Step 206 is performed until a predetermined reaction force FPD is detected (indicating that the electrode has contacted the reference surface). Step 208 (which is optional) can be performed to make sure that a steady-state displacement has been reached. In step 210 a correction value DIFF is computed from the difference between the expected and actual amounts of displacement. Step 212 is performed later when the electrode which has just been tested is to be used for fusing. Step 212 adjusts the location of the turret at the start of each fusing cycle so that the tip of the electrode always starts from predetermined rest position 17.
FIG. 12 is the analog of FIG. 11 using closed loop displacement control. In step 222 closed loop displacement of an electrode toward a reference surface begins. Step 224 is performed until controls 48 detect that displacement has stopped (because the electrode has reached the reference surface). Step 226 (which is optional) is performed to ensure that a steady-state reaction force condition has been reached. Steps 228 and 230 are then respectively identical to steps 210 and 212 in FIG. 11.
As an alternative to using a specially provided reference surface such as reference surface 18' in FIG. 1, it may be possible to use a surface of the workpiece (i.e., a surface of the armature commutator) as the reference surface. For example, if the armature has slots 319 for receiving coil leads 319" as shown in FIG. 13, rather than tangs as shown in FIG. 1, the radially outer-most surfaces 320 adjacent the slots may be sufficiently precisely located to act as a reference surface. In that event, the electrode position can be determined by monitoring force and/or motion replies as shown in FIG. 11 or 12 using initial contact against commutator surface 320 in order to reference the fusing cycle parameters accordingly. (For commutators with tangs as shown in FIG. 1, initial contact of an electrode with a tang is generally not a sufficiently reliable indicator of electrode position because commutator tangs are not typically machined with sufficient precision, nor do they typically offer sufficient and consistent resistance to initial deformation.) In addition, with slot-type commutators, it may be desired to reference the final deformation of the fusing operation to the point of initial contact with surface 320 rather than to the remainder of the commutator bar. This may make it unnecessary to determine the eccentricity of the commutator bar as may be required for commutators with tangs and as is discussed elsewhere in this specification.
In cases in which it is sufficient to determine the location of the tip of a new electrode with somewhat less precision, it may be sufficient to bring the electrode tip into contact with a switch placed in a known position rather than into contact with a reference surface. Such a switch can be a contact switch or an optical sensor which supplies a signal (ON or OFF) indicating that the corresponding monitored displacement should be used to calculate the new position of the electrode tip.
An analysis of the force and motion experienced by electrode 11 in contacting the reference surface supplies information for determining whether electrode 11 has been securely mounted on turret 10. Such an analysis is achieved by the controls 48 of the machine and consists of comparing the monitored force (e.g., from step 206 in FIG. 11 or step 226 in FIG. 12) and motion (e.g., from step 208 in FIG. 11 or step 224 in FIG. 12) experienced by electrode 11 during contact with the reference surface with predetermined force and motion values calculated for contact of a properly secured electrode 11 against the same reference surface. For example, if the expected force reply or motion reply does not occur within a predetermined displacement interval of the electrode (i.e., larger than the maximum uncertainty which the position of the electrode tip may have), this probably means that the electrode has been mounted incorrectly. This technique can be used to help ensure safe functioning of the machine.
To obtain passage of an electric current by means of supply cable 38, a ground electrode 80 must be connected to the parts to be fused. To attain this, ground electrode 80 is maintained in engagement with the commutator bar 19' of the tang 19 to be fused. Usually automatic change over of ground electrode 80 is not required because such a member becomes worn at a much slower rate than that of electrodes 11 which come into contact with the parts to be fused.
With reference to FIGS. 7 and 8 an L fixture 82 is provided having ground electrode 80 clamped in location 83. Fixture 82 is releasably clamped between a face of shaft 85 and a nut having handle 87 (not shown in FIG. 7 but shown in FIG. 8). Slot portion 84 of fixture 82, embracing a threaded portion of shaft 85, is compressed between handle 87 and the front face of shaft 85. This allows for precise positioning of ground electrode 80 in relation to the armature by simply releasing handle 87 and moving fixture 82 in relation to shaft 85. Ground electrode 80 is usually substituted by releasing handle 87, removing fixture 82 and replacing it with a similar fixture having a new electrode.
Shaft 85 is mounted on bushings of support enclosure 89. In this way, shaft 85 can rotate about axis 88 in order to bring electrode 80 into engagement with the commutator bar when required to fuse, or, when required to disengage the electrode from the commutator bar before rotating the armature to present a new tang for fusing on axis 42.
Support enclosure 89 is connected to the machine frame by means of bolts passing through appropriate bores.
Air cylinder 91 is hinged by pin 90 to support enclosure 89. The air cylinder's rod is connected by means of fork 92 to arm 93 of shaft 85. By extending the air cylinder's rod, ground electrode 80 can be rotated about axis 88 of shaft 85 to engage or disengage the ground electrode from the commutator bar. A ground electrode braid (not shown) is permanently connected to an extension of arm 93 by means of a bolt connection.
Once a tang of the armature commutator has been fused, electrode 11 is returned to rest position 17 and the armature is rotated about its longitudinal axis to align a further tang on axis 42. Assembly 96 (FIG. 9) maintains the armature in position during the fusing cycle by keeping the commutator's outer surface in abutment with reaction block 110. Also, assembly 96 rotates the armature to present or align a further tang on axis 42.
Assembly 96 is provided with a gripper portion 98 for gripping armature shaft 97. Such a gripper portion 98 consists of split collet 99 for gripping armature shaft 97. The external surface of collet 99 is engaged by a frustoconical front portion of actuating tube 100. Actuating tube 100 slides on portion 95 of supporting tube 94. A precompressed spring 101 biases actuating tube 100 to force collet 99 to grip shaft 97 of the armature which must be fused.
Removable cap 102 allows for replacement of collet 99 when it is required to grip an armature having a different shaft diameter. When different commutator diameters are processed, reaction blocks 110 (FIG. 1) are also changed in order to maintain the central longitudinal axis 117 of the armature at the same level from the machine work table 111. In other words, reaction block 110, acting as a spacer between fixed surface 111 and the commutator of an armature, is changed to a block 110 having a different thickness when commutators of different diameters are to be fused so that the distance between surface 111 and axis 117 is always substantially the same.
Support tube 94 mounted on bearings 107, is able to rotate about axis 117 in order to turn the armature for presenting a further tang for fusing on axis 42. Toothed pulley wheel 112 fixed to support tube 94 is connected by means of a belt transmission to a motor (not shown). This motor is precisely controlled in order to obtain rotation of the armature to position a further tang for fusing.
Actuating tube 100 is connected to shaft 150 which can translate along axis 117 by being slideably supported in bushing 108. Enclosure 103 carrying bearings 107 has connected to its back end a cylinder 109. This cylinder has a hollow piston 113 for passage of shaft 150. Shaft 150 has fixed to its end a pushing block 114. By pressurizing chamber 118 of cylinder 109, hollow piston 113 abuts and moves pushing block 114 in direction 115. This causes shaft 150 to translate against the biasing action of precompressed spring 101 in order to release armature shaft 97. By discharging chamber 118 the opposite effect can be obtained, i.e , spring 101 biases actuating tube 100 to cause collet 99 to grip armature shaft 97.
Enclosure 103 is mounted on slide 104 so that assembly 96 can be translated in direction 116. Such a translation of slide 104, is accomplished to deliver the armature or to receive it during loading or unloading of the fusing machine. Enclosure 103 is hinged to slide 104 by means of pin 105. Enclosure 103 is biased against slide 104 by means of precompressed spring assembly 106. This spring assembly, which allows angular displacement of support tube 94 about pin 105, is required to guarantee that the commutator is held against reaction block 110 during the fusing operation. Spring assembly 106 also allows for smooth rotation of the commutator on the reaction block 110 during rotation of the armature to present a further tang for fusing. This smooth rotation is obtained because any eccentricity of the commutator's outer surface causes the slide to rotate about pin 105 in order to avoid forcing the commutator against reaction block 110.
It will be understood that the foregoing is merely illustrative of the principles of the invention, and that various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention. For example, certain of the principles discussed herein (e.g., the techniques for measuring the location of the tip of a new electrode, the use of a fusing cycle start position which is always at a predetermined distance from the work-piece and which is closer to the workpiece than an electrode changing position, the use of position sensor 45 or another type of sensor to sense the location of the surface of the workpiece in order to modify the fusing cycle or the fusing cycle stroke, etc.) are equally applicable to other types of fusing machines such as those having only a single fusing head with no rotating turret.
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Apparatus for fusing electric motor parts (e.g., fusing electric motor armature coil leads to the commutator of the armature) includes positive control of the elements which move to perform the fusing cycle so that the fusing cycle stroke can begin at any desired location. This facilitates shortening the stroke and making it constant despite changes or deviations in the workpieces being fused. It also facilitates withdrawal of the fusing head to a location which is more remote from the workpiece when the fusing electrode is to be changed due to wear. In fusing machines having a rotating turret which carries several fusing electrodes, the mass of the moving parts is reduced by mounting the actuator which reciprocates the turret on the frame of the machine, and by deriving the motion required to rotate the turret from the reciprocation rather than from a separate actuator.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a looper for a tufting machine, etc.
2. Description of the Prior Art
In FIG. 1, a conventional looper 1 of a tufting machine is shown. There is formed a projecting guide part 3 in a base 2 of the looper 1, while, there is provided a blade portion 4 on a side of the guide part 3. At the end of the guide part 3 (on the right side as viewed in FIG. 1), there is formed a thread-hook 5 which is substantially bent in the shape of a letter L. Steel is chosen as material for the looper 1. When a tufting needle (not shown) operating in the tufting machine is penetrated through a workpiece 6 such as a cloth, carpet, and the like, the thread-hook 5 is passed through a loop-shaped pile thread 7. The loop-shaped pile thread 7 is cut off by the blade portion 4 of the guide part 3 and a cutting member (not shown) abutting thereagainst to make the workpiece form piles.
In such prior art arrangement, when the looper 1 is operated continuously at high speed, the blade portion 4 is frequently broken or the looper 1 is deformed, with the result that the pile thread 7 cannot be smoothly cut.
SUMMARY OF THE INVENTION
Accordingly, in order to solve the above problems, it is an object of the invention to provide a looper of such a tufting machine which has sufficiently high durability such that it may be used for a long period of time.
To achieve the object, the looper in accordance with the invention has a hardened metal facing coating layer applied on at least one side thereof.
In a preferred embodiment, the hardened metal facing coating layer consists of titanium nitride (TiN).
Consequently, in accordance with the invention, the looper is covered with the hardened metal facing coating layer, thereby inhancing the hardness of the looper and hence the durability thereof as well. As a result, the cutting of the pile thread can be smoothly performed for a long period of time.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects, features and advantages of the invention will become more apparent from the following detailed description taken with the accompanying drawings, in which:
FIG. 1 is a front view showing the looper of the prior art mentioned already; and
FIGS. 2a and 2b are front views showing loopers according to embodiments of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, embodiments of the invention are described below.
A hardened metal facing coating layer 8 is applied on each of the surfaces of loopers 1 shown in FIGS. 2a and 2b. As material for the hardened metal facing coating layer 8, titanium nitride (TiN) is suitably used. To cover the looper 1 with titanium nitride (TiN), what is called an ion-plating method is employed. Namely, titanium (Ti) is evaporated in space in which glow discharge is performed through nitrogen (N) gas, and then resultant titanium nitride (TiN) is deposited on the surface of the looper 1 charged with negative electricity, thus effecting the covering of the hardened metal facing coating layer 8.
Based on experiments carried out by the present inventor, the following advantages due to applying the hardened metal facing coating layer 8 on the looper 1 can be obtained:
(a) Hardness of the looper 1 can be increased. More particularly, when the thin film 8 consisting of titanium nitride (TiN) is 1 to 2 μm thick, the useful life of looper 1 becomes more than twice as great as that of the conventional looper, thus leading to an inhancement of durability of the looper 1.
(b) It is possible to make the hardened metal facing coating layer 8 a golden color itself. Furthermore, since the tint of the layer can be varied within the range from yellowish to reddish, it is also possible to provide a particularly desired to the inner shuttle.
(c) The heat conducting capability of the looper 1 can be improved. Consequently, since the looper 1 is easy to cool, not only the durability thereof can be further improved, but also sharpness of the blade can be maintained for a long period of time. Additionally, the shape of the looper 1 is not limited to those shown in FIGS. 2a and 2b, and the present invention is applicable to loopers of various shapes.
The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and the range of equivalency of the claims are therefore intended to be embraced therein.
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A looper of a tufting machine, has a hardened metal facing coating layer which consists of titanium nitride (TiN) applied on one side or both sides thereof by means of an ion-plating method.
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This utility patent application claims the benefit of provisional application No. 60/267,311, filed Feb. 8, 2001.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to lines, leaders, tippet material, or tapered leaders (for sake of brevity hereinafter called “fishing line or lines”), used in various types of fishing applications and, more particularly, is concerned with an enhanced fishing line having a unique combination of properties in terms of breaking strength, elongation, knot breaking strength, breaking toughness, and flexibility stiffness.
2. Description of the Prior Art
Synthetic monofilament fishing lines, comprised of synthetic polymeric materials such as polyamides, polyesters, polyethylenes, or fluoropolymers, have long been used in fishing applications. The synthetic monofilament fishing lines employed in the prior art have traditionally attempted to achieve the highest possible breaking strength with the smallest possible diameter. The objective of creating fishing lines with the smallest possible diameter is to make the fishing line as inconspicuous as possible so as to increase the potential for attracting the fish to the bait or fly, while also providing as high a strength as possible in order to hook-up and land the larger fish.
This traditional way of making fishing lines has several disadvantages associated with it that have not yet been overcome in the design and construction of fishing lines. Due to the nature of the polymeric materials used to make the monofilament fishing lines, the material becomes increasingly stiffer in order to achieve a high ultimate breaking strength. The stiffness of the material is related to its elongation, or the ratio of the extension of the material to the initial length of the material prior to stretching. The increased stiffness of the material results in the line becoming less flexible which tends to make tying knots in the line more difficult and also tends to dramatically reduce the breaking strength of the line at the knot.
In addition, stiffer, stronger lines have less capacity to resist shock or rapid impact loading conditions before breaking, such as when a fish is hooked-up and rapidly swims in a direction away from the rod and reel to place a rapid loading on the line. The capacity to resist rapid loading conditions is referred to as the breaking toughness of the line. Lines that have a high breaking strength will generally have a lower ultimate elongation and a correspondingly low breaking toughness. The lower breaking toughness is what causes the instantaneous breakage of the line under the rapid impact conditions. Since the line breaks almost instantaneously, the fisherman does not have ample time to react and relieve the pressure in the line by either raising the tip of the rod or allowing the line to come off the reel. Therefore, more fish are lost after the initial hook-up due to breaking of the line from these rapid loading conditions as a result of its lower breaking toughness.
By observing and studying prior art fishing lines and statements that are made with regard to the benefits of the so-called high-performance fishing lines, one concludes that current state-of-the-art practices employed to improve performance of fishing lines primarily involve making fishing lines that have higher ultimate breaking strength and correspondingly thinner diameters. The apparent intent is to achieve a higher ultimate knot breaking strength while the critical property of breaking toughness is ignored.
Tests conducted on prior art fishing lines demonstrate this assertion. The so-called high performance fishing lines do generally have higher ultimate breaking strength and thinner diameters. However, there is generally only a marginal benefit, if any, in terms of a higher ultimate knot breaking strength. They also have relatively lower ultimate elongation, significantly lower breaking toughness and significantly less flexibility by virtue of their higher flexibility stiffness.
The test equipment used to measure the aforesaid properties of fishing lines is a conventional universal testing machine, such as those under the Instron name, and the tests are conducted in accordance with test procedures outlined in ASTM D-2101-91 where a constant rate of extension of ten inches per minute and a specimen gauge length of 10 inches were used.
As referred to herein, the various properties are defined as follows. The Ultimate Breaking Strength is defined as the force required to break the line divided by its cross sectional area, whose value is presented with units of pounds per square inch (also referred to as psi herein). The Ultimate Knot Breaking Strength is defined as the force required to break the line divided by its cross sectional area, with an overhand knot tied into the line, whose value is presented with units of pounds per square inch. The Ultimate Elongation is defined as the ratio of the extension of a material at the breaking point, to the length of the material prior to stretching, whose value is presented as a percentage. The Breaking Toughness is defined as the actual work per unit volume of material that is required to break the material, whose value is presented with units of inch-pounds per cubic inch. The Flexibility Stiffness is defined as the stiffness of the material measured between 5% and 10% elongation and is determined by subtracting the stress in the monofilament at which 5% elongation is achieved from the stress in the monofilament at which 10% elongation is achieved, and dividing this difference by the 5% difference in elongation. The lower the Flexibility Stiffness, the more flexible the monofilament.
Due to the adverse effects on performance from the tradeoffs associated with prior art fishing lines, there exists a need for an enhanced fishing line having a unique combination of the aforementioned properties which improves performance.
SUMMARY OF THE INVENTION
The present invention provides an enhanced fishing line designed to satisfy the aforementioned need. The enhanced fishing line of the present invention is adapted for use in various types of fishing applications and provides a product having superior properties over those presently on the market which improves performance. In particular, the enhanced fishing line of the present invention has a unique combination of ultimate breaking strength and ultimate elongation properties so as to provide a fishing line with a significantly higher breaking toughness and with an optimal ultimate knot breaking strength, and lower flexibility stiffness, so as to provide a fishing line with significantly higher performance.
Accordingly, the present invention is directed to a fishing line which comprises: (a) a monofilament made of a polymer, such as a polyamide, such as nylon 6, nylon 66, nylon 612, nylon 11, and nylon 12; or a fluoropolymer, such as polyvinylidene fluoride; or a polyolephine, such as polypropylene; (b) the monofilament having an ultimate breaking strength of a minimum of about 150,000 psi, an ultimate elongation of a minimum of about 30%, an ultimate knot breaking strength of a minimum of about 130,000 psi, a breaking toughness of a minimum of about 25,000 inch-pounds per cubic inch, and a flexibility stiffness of no greater than about 500,000 pounds per square inch.
More particularly, the monofilament has a diameter of between about 0.003 inches to 0.045 inches, and is manufactured by an extrusion process followed by a drawing process, such that the monofilament has an extruded diameter between about 1.1 and 1.4 times the finished diameter after drawing.
Further, the ultimate breaking strength of the monofilament is within a range of about 150,000 to 180,000 psi. The ultimate elongation of the monofilament is within a range of about 30% to 100%. The ultimate knot breaking strength of the monofilament is within a range of about 130,000 to 170,000 psi. The breaking toughness of the monofilament is within a range of about 25,000 to 35,000 inch-pounds per cubic inch. Also, the monofilament has a flexibility stiffness of about 225,000 to 500,000 pounds per square inch.
These and other features and advantages of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The enhance fishing line of the present invention is a monofilament made of a polymer, preferably a polyamide, such as nylon 6, nylon 66, nylon 612, nylon 11, and nylon 12; or a fluoropolymer, such as polyvinylidene fluoride; or a polyolephine, such as polypropylene. The monofilament has a finished diameter of between about 0.003 inches to 0.045 inches.
The monofilament preferably is made by an extrusion process, followed by a drawing process where the extruded diameter is between 1.1 and 1.4 times the diameter of the finished monofilament after stretching or drawing. Specifically, in a set of representative examples, a quantity of the polymer, as described above, is extruded using conventional extruding equipment to provide an extruded monofilament of between 1.1 and 1.4 times the finished diameter of the monofilament. The extruded monofilament is then subjected to a drawing process where the monofilament is stretched out along its length and results in a corresponding reduction in the diameter of the monofilament until the finished diameter is achieved. The drawing process aligns the molecular chains in a direction parallel to the long axis of the monofilament thereby increasing the ultimate breaking strength of the material along with its stiffness. After the drawing process, the monofilament is heat treated to relieve the high stresses, which can exist near the surface of the monofilament as a result of the drawing process. This heat treatment subjects the monofilament to a temperature range of between 40 and 150 degrees Celsius for a time period of between 30 minutes and 4 hrs. After heat treating the monofilament can further be subjected to an irradiation process, wherein the monofilament is exposed to gamma irradiation or electron beam to achieve an accumulation of 0.5 to 100 mega rads of exposure. The irradiation process promotes cross linkage of the molecules and results in lower flexibility stiffness and greater ultimate elongation while maintaining a high ultimate breaking strength.
The aforementioned extrusion, drawing, treatment processes are set to instill the enhanced fishing line with a unique combination of properties which include the following. The enhanced fishing line will generally have a minimum ultimate breaking strength of 150,000 psi (pounds per square inch) or within a range of about 150,000 to 180,000 psi, a minimum ultimate elongation of 30% or within a range of about 30% to 100%, a minimum ultimate knot breaking strength of 130,000 psi or within a range of about 130,000 to 170,000 psi, a minimum breaking toughness of 25,000 inch-pounds per cubic inch or within a range of about 25,000 to 35,000 inch-pounds per cubic inch, and a flexibility stiffness of no more than 500,000 psi or within a range of about 225,000 to 500,000 psi, based on averaging the test results for a total of five specimens from the same production lot being tested using a universal testing machine in accordance with test procedures outlined in ASTM D-2101-91 at a constant rate of extension of ten inches per minute and a specimen gauge length of 10 inches.
Following the aforementioned steps of the extrusion and drawing processes, samples were made of monofilament fishing line having the minimum ultimate breaking strength of 150,000 psi and the minimum ultimate elongation of 30% that resulted in the line having the ultimate knot breaking strength of more than 130,000 psi, a breaking toughness of more than 25,000 inch-pounds per cubic inch, and a flexibility stiffness of less than 500,000 psi.
FIG. 1 presents a table of Fishing Line Test Data which includes data for the enhanced monofilament fishing line samples along with data for prior art fishing line samples that were available in the market. Column (1) presents the diameter values of the fishing line samples in inches. Column (2) presents the ultimate breaking strength values of the fishing line samples in pounds per square inch. Column (3) presents the ultimate elongation values of the fishing line samples in %. Column (4) presents the ultimate knot breaking strength values of the fishing line samples in pounds per square inch. Column (5) presents the breaking toughness values of the fishing line samples in inch-pounds per cubic inch. Column (6) presents the flexibility stiffness values of the fishing line samples in pounds per square inch. Rows (A) through (C) present the test data for the enhanced fishing line samples according to the current invention. Rows (D) through (M) present the test data for typical prior art lines.
Observing the test data for the enhanced lines according to the present invention, one can readily observe that the combination of ultimate breaking strength greater than 150,000 psi and ultimate elongation greater than 30% produce levels of ultimate knot strength greater than or equal to 130,000 psi, breaking toughness greater than or equal to 25,000 in-pounds per cubic inch, and flexibility stiffness less than or equal to 500,000 psi. In the case of prior art samples such as the samples in rows (F), (G), (H), (I), (J), (L), and (M), the ultimate breaking strength is greater than 150,000 psi, however, the ultimate elongation is considerably less than 30% for each of these samples, resulting in low ultimate knot strength values of less than 130,000 psi, low breaking toughness values of less than 25,000 in-pounds per cubic inch, and flexibility stiffness greater than 500,000 psi. In the case of the prior art sample in row (E), the ultimate elongation is higher at 30.385%, however, the ultimate breaking strength is considerably less than 150,000 psi, and the ultimate knot strength is also considerably less than 130,000 psi. Therefore, one can readily observe from the data in FIG. 1 that the unique combination of high ultimate breaking strength (at least 150,000 psi) and high ultimate elongation (at least 30%) produces enhanced performance with regard to greater ultimate knot breaking strength (at least 130,000 psi), greater breaking toughness (at least 25,000 in-pounds per cubic inch) and reduced flexibility stiffness (no greater than 500,000 psi) which results in greater flexibility.
Field testing of these fishing line samples, which were made in the form of tippet material for fly fishing, has confirmed the unique, positive benefits of the improved fishing line having the unique combination of properties mentioned previously. The additional benefit of increased flexibility was also realized as demonstrated by the ease with which knots were able to be tied and by the natural way in which the tippet material presented the fly.
It is thought that the present invention and its advantages will be understood from the foregoing description and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely preferred or exemplary embodiment thereof.
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An enhanced fishing line has a unique combination of breaking strength and elongation properties to provide a high level of flexibility, a high ultimate knot breaking strength, and a high level of breaking toughness that is defined as the actual work per unit volume of material required to break the material. The line is a monofilament construction made of a synthetic polymeric material such as a polyamide, polyester, polyethylene, or fluropolymer and manufactured by an extrusion process followed by a drawing process where the extruded diameter is between 1.1 and 1.4 times the diameter of the finished line after drawing.
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BACKGROUND OF THE INVENTION
In the prior art, hammer drills originally had only forwardly rotated motors and therefore the hammering mechanisms could operate at will whenever the selector was set for the hammer mode. However, with the use of reversing switches, which are desirable for the drilling operation, it became necessary to instruct the operator not to use reverse during hammering. Such a warning is not a solution, but unfortunately the operator had no restraint against operating the tool in reverse during hammering. Manual biasing means present a partial solution, but can be defeated by an operator's manual override.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved reversing hammer drill which overcomes the prior art disadvantages; which provides a bypass switch for forward motor operation in the hammer mode; which has a DPDT bypass switch in circuit with the trigger switch and reversing switch; which permits forward or reverse drilling, but prevents reverse hammering; which adds a bypass switch to prevent damage to the hammering mechanism, and which uses a bypass switch selectively to shunt the reversing switch.
Other objects and advantages will be apparent from the following description of the invention and the novel features will be particularly pointed out hereinafter in the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
This invention is illustrated in the accompanying drawings in which:
FIG. 1 is a side elevational view of a hammer drill embodying the present invention.
FIG. 2 is a schematic diagram of the electric circuit of the hammer drill.
FIG. 3 is a bottom view, partly broken away and in section, of the front end of the hammer drill showing the bypass switch and lever mechanism which operates the same.
FIG. 4 is a top plan view, partly broken away and in section, of the front end of the hammer drill showing the selector in the drill setting.
DESCRIPTION OF THE INVENTION
In the illustrated embodiment of the invention, a hammer drill, designated generally 10, is shown in FIG. 1, and has a housing 12 in which is journaled a universal motor 14 having an armature shaft 16 which carries a commutator 18, engaged by a brush assembly 20. An armature 22 is affixed to the shaft 16, and a stator field 24 is disposed thereabout. The armature shaft 16 is journaled by a pair of spaced bearings 26 and 28, and has a drive pinion 30 extending into a gear chamber 32 to drive a gear train 34. The last gear of the train 34 is a spindle gear 36 which is affixed to a spindle shaft 38 by a key 40. The spindle 38 extends externally of the housing 12 and has affixed thereto a chuck 42 to which a suitable tool bit (not shown) will be connected to engage the work. The housing 12 has a pistol grip handle 44, the lower end of which receives an electric cord 46 the end of which has a plug 48 shown in FIG. 2 adapted to be connected to a suitable source of electric power. The cord 46 is in circuit with switch assembly 50 including a trigger switch 52 actuated by a trigger 54, and a rotation reversing switch 56 affixed atop the trigger switch 52 and actuated by a pivotal lever 58. A bypass switch 60 is also included in the switch assembly 50 and is mounted in the housing 12 below the front bearing 28 in the wall 62 with the switch body 64 disposed in the motor chamber 66 and the switch toggle 68 extending into a bypass switch chamber 70 formed below the gear chamber 32.
FIG. 2 is a schematic diagram for the hammer drill 10 wherein the motor 14 and its armature 22 and field 24 has its on-off condition controlled by the trigger switch 52. The bypass switch 60 is preferably a double pale-double throw (DPDT) switch with its center contacts 72,72 in circuit with the trigger switch 52. When the right contacts 74,74, as viewed in FIG. 2, are connected to the center contacts 72,72, as they will be in the hammer mode as explained more fully hereinafter, the armature 26 and consequently the motor 14 will be rotated in the forwardly direction. By connecting contacts 72 and 74, the reversing switch 56 is shunted from the circuit. Therefore, even if the reversing switch is manually positioned in the reverse setting, it will have no effect upon the circuit operation. When the tool 10 is placed in the drill mode, the bypass switch will have the left contacts 76,76, as viewed in FIG. 2, engaged with contacts 72,72 to place the reversing switch 56 in circuit so as to permit the operator to select forward or reverse rotation of the motor 14. A suitable speed control device (not shown) for controlling the motor 14 speed can be included in circuit integrally connected to or separate from the trigger switch 52, as desired.
The spindle 38 illustrated in FIG. 1 has a limited axial movement within a sleeve bearing 78 so that the spindle may be axially shifted between the drill and the hammer positions, and also is free to be axially shifted to partake of the hammering ratchet action during the hammer mode of operation. A washer 80, spacer 82 and thrust bearing 84 are disposed about the spindle 38 forwardly of the spindle gear 36 to abut a stationary ratchet 86 affixed within the nose 88 of the housing 12. The ratchet 86 has a front face 90 fitted with annular angular teeth 92 in spaced relationship to the spindle 38, and radially outwardly thereof is a first aligned drill set surface 94 with holding dimple 96, and a second axially set-back hammering set surface 98 with holding dimple 100. A spindle collar 102 has the chuck 42 abut its outer end, and a journal section 104 is formed inwardly, or as viewed in FIG. 1, on the left side of the collar 102. A ball bearing 106 journals the section 104 at its inner end, with a plurality of spring washers 108 disposed between the collar 102 and the bearing 106. A threaded section 110 having left hand threads is formed on the left side of the journal section 104 at a slightly reduced diameter. An annular clutch 112 is connected upon the threaded section 110 to abut the inner race of the bearing 106. Angular teeth 114 face the anular teeth 92 of the ratchet and in the drill setting shown in FIGS. 1 and 4 are held in spaced relationship therewith so that the spindle 38 will only rotate. A set or selector ring 116 is turnably fitted within the stationary ratchet 86 with its enlarged inner end abutting the inner face of the outer race of the bearing 106. The inner or leftward edge 118 has a small projection 120 which will fit within to be yieldably held in one or the other of the dimples 96 or 100. Whenever the operator desires to change the mode of operation from that of drill to that of hammer, the ring 116 will be turned to remove the projection 120 from engagement within drill dimple 96 as shown in FIG. 1 to cause the projection 120 to engage the hammer dimple 100 which will produce a slight inward axial shifting of the ring 116 and spindle 38 to abut the corresponding clutch teeth 114 with the ratchet teeth 92. This change is mode of operation will be visually shown by the indicator 122, illustrated in FIG. 4, being shifted from its alignment with the "drill" marking to that of the "hammer" marking. The corresponding teeth 92 and 114 are angled to rotate forwardly to produce the ratcheting or hammering effect. The engaged teeth continuously ride over and fall to produce the back and forth axially shifting or "hammering". The forward rotational direction is assumed to be rightward or clockwise rotation. The reverse rotational direction is assumed to be leftward or counterclockwise rotation.
In the event the operator were able to accidentally set the reversing switch 56 to reverse and the ring 116 to hammer, the sets of teeth 92 and 114 would lock down against each other. This would either stall the motor 14 which might cause it to burn out, or the clutch 112 could be unthreaded from the left hand threads of the section 110 of the spindle 38, or the teeth or other parts of the mechanism could be damaged.
It is the principal purpose of the present invention to eliminate the possibility of the operator being able to place the hammer drill 10 in the reverse mode of operation whenever the indicator 122 is set for the hammer operation. This is done by the bypass switch 60 shunting the reversing switch 56 upon the selector ring 116 being set for "hammer", and restoring the switch 56 in circuit when the ring 116 is again set for "drill".
The housing 12 shown in FIG. 1 has the motor chamber 66 which is made up of two clamshell portions 124, 126 (see FIGS. 3 and 4) interconnected to each other by screws 128. A strip nut 130 is disposed into aligned recesses formed within each of the clamshell portions 124, 126 so that, upon the motor section being assembled, the strip nut 130 will be locked in position therein. A head section 132 in which the gear chamber 32 is formed carries the gear train 34 and the chuck 42. The head section 132 is connected to the assembled clamshell portions 124, 126 via long screws 134, illustrated in FIGS. 3 and 4, being threadedly received in tapped holes 136 of the strip nut 130.
A partition 138 shown in FIG. 1 separates the gear chamber 32 from the bypass switch chamber 70. An aperture 140, illustrated in FIGS. 1 and 3, is formed at the nose 88 end of chamber 70 below the partition 138 and extends substantially horizontal. The selector ring 116 has a narrow recess 142 in alignment with the aperture 140 so that when the ring 116 is placed in the drill setting shown in FIG. 4, the recess 142 will be positioned adjacent the top edge 144 as indicated by the dotted line representation of the recess 142 illustrated in FIG. 3. Shifting of the selector ring 116 to set it by hammer will, if viewed from the front of the hammer drill looking toward the chuck 42, require a counterclockwise motion of the ring 116 that will result in the recess 142 being placed opposite the bottom edge 146 as shown in the solid line representation of FIG. 3.
A lever 148 illustrated in FIGS. 1 and 3 is pivotally connected to the underside of the partition 138 by a rivet 150. The forward end 152 of the lever 148 exits the chamber 70 through the horizontal aperture 140 and its tip 154 enters the recess 142 which is longer than it is wide so that any slight shifting thereof responsive to rotation of the selector ring 116 will cause the tip 154 to engage the walls of the recess 142 and be shifted thereby. The rear portion of the lever 148 has a leg 156 which turns downwardly at a right angle above the toggle 68 so that a slot 158 formed near its lower end will entrap the toggle 68 therein and cause it to shift in the opposite direction as that of the tip 154. The operative positions of the bypass switch 60 are shown in FIG. 3 in which the solid line representation of the toggle 68 is in the upper position and lever 148 is slanted downwardly towards the right which corresponds to the hammer mode of operation wherein the switch 60, contacts 72 and 74 illustrated in FIG. 2 are connected to shunt the reversing switch 56 so that motor 14 can rotate only in the forward direction. When the selector ring 116 is shifted from hammer to drill, which is the FIG. 4 setting with the indicator 122 opposite the drill rotation, the bypass switch 60 will be switched to the dotted line representation shown in FIG. 3 in which the toggle 68 is in the lowered position and the lever 148 slanted upwardly towards the right. In the drill set position, the bypass switch 60 will connect contacts 72 and 76 illustrated in FIG. 2, to place the reversing switch 56 in circuit to control whether the motor 14 is rotated in the forward or reverse rotational direction.
It will be understood that various changes in the details, materials, arrangements of parts and operating conditions which have been herein described and illustrated in order to explain the nature of the invention may be made by those skilled in the art within the principles and scope of the invention.
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A hammer drill having a bypass switch which is activated by the selector ring to prevent the drill from operating in the hammer mode by shunting the reversing switch. This is a precaution to prevent damage to the clutch teeth which are designed for ratchet action when the tool is operated in the forward direction, but will lock down in reverse to stall tool or damage the mechanism. In the drill mode, the bypass switch connects the reversing switch in circuit with the on-off switch.
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RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. provisional patent application No. 60/388,832 filed on Jun. 13, 2002.
FIELD OF INVENTION
[0002] The present invention relates to a computer method and system for simulating an online session while offline, and more particularly, to such a method and system in the field of customer relationship management.
BACKGROUND OF THE INVENTION
[0003] The Internet provides the capability to provide services to customers without requiring them to install additional software on their local computers. Specifically, by exploiting the customer's web browser, all functional logic and all data can reside at a remote server rather than at the customer's local computer (i.e., the client). As such, the customer, via instructions submitted through web pages that are displayed in the web browser, can remotely invoke the functional logic to view, create, update, delete or otherwise modify the data residing on the remote server.
[0004] In the field of customer relationship management (“CRM”), the foregoing use of the Internet is ideal for enabling sales, customer support, and marketing teams and individuals to organize and manage their customer information. For example, all leads, opportunities, contacts, accounts, forecasts, cases, and solutions can be stored at a secure data center but may be easily viewed by any authorized sales-person (e.g., with a proper username and password) through a web browser and Internet connection. One key benefit of such an online CRM solution is the ability to share data real-time and enable all team members to leverage a common set of information from one accessible location. For example, sales managers can track forecast roll-ups without requiring each sales representative to submit individual reports, as well as instantly access aggregated sales data without requiring each sales representative to manually submit such data. Similarly, reseller sales representatives and other external partners can be granted secure access to a company's sales data by providing them a username and password for the web site.
[0005] Nevertheless, such an online CRM solution suffers from the requirement that a user must have access to an Internet connection in order to access and manipulate the data residing on the remote server. For example, when a sales representative or manager is working in the field, such an Internet connection may not be readily available. As such, what is needed is a method for simulating an online session while the user is offline (e.g., without a network connection). Furthermore, it would be advantageous if such a method minimized the amount of user training and client-side installation and customization by taking advantage of pre-existing interfaces and technologies on the client computer.
SUMMARY OF THE INVENTION
[0006] The present invention provides a method and system for simulating an online session between the client and a remote server when the client is offline. The client includes a local interface that can communicate with the remote server. During an online session, the data and the functional logic that is invoked to manipulate the data reside on the remote server. As such, the user transmits instructions to view, create, update, delete, or otherwise modify portions of data through the local interface and subsequently through the underlying network. These instructions are ultimately received at the remote server, which then invokes the proper functional logic to perform the instructions in order to manipulate the data.
[0007] In preparation for simulating an online session when the client is offline, when the client is online, it imports at least a subset of the data that resides at the remote server. Furthermore, the client imports at least a subset of the functional logic used to manipulate the data as an embedded portion of a format or document that is capable of being interpreted and performed by the local interface. To initiate an offline session, the user invokes the local interface (as in the online session). However, rather than accessing the remote server, the local interface accesses local documents formatted with the embedded functional logic. As in the online session, the user transmits instructions to view, create, update, delete, or otherwise modify portions of data through the local interface. However, rather than transmitting the instructions through an underlying network, the local interface invokes the embedded functional logic in the documents to manipulate the imported data in response to the instructions.
[0008] As such, the present invention provides an offline simulation of an online session between the client and a remote server. Because the same local interface that is used in the online session is also used in the offline session, user training for the offline session is minimized or even eliminated. Furthermore, since functional logic is embedded into a format capable of being interpreted and performed by the local interface, the need to install additional standalone software applications is also minimized or eliminated. Further objects and advantages of the present invention will become apparent from a consideration of the drawings and detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a diagram illustrating an online session between a client with a local interface and a remote server with a relational database and functional logic.
[0010] FIG. 2 is an example of a client initiation of an online CRM session with a remote server.
[0011] FIG. 3 is an example of the presentation of CRM data on a client's web browser during an online CRM session.
[0012] FIG. 4 is a diagram illustrating an offline session.
[0013] FIG. 5 is a expanded block diagram illustrating one embodiment of the various phases used to provide a client with the capabilities of engaging in an offline CRM session.
[0014] FIG. 6 is a flowchart illustrating one embodiment of a process for conducting an offline CRM session.
[0015] FIG. 7 is an example of a login session to connect to a remote server during a synchronization process.
[0016] FIG. 8 is an example of a visual representation of a synchronization process with the remote server.
[0017] FIG. 9A is a first example of the presentation of CRM data during an offline session (Home View).
[0018] FIG. 9B is a second example of the presentation of CRM data during an offline session (Home View).
[0019] FIG. 9C is a third example of the presentation of CRM data during an offline session (Home View).
[0020] FIG. 9D is a fourth example of the presentation of CRM data during an offline session (Home View).
[0021] FIG. 9E is a fifth example of the presentation of CRM data during an offline session (Home View).
[0022] FIG. 10A is an example of the presentation of “Accounts” CRM data during an offline session (Home View).
[0023] FIG. 10B is an example of the presentation of “Accounts” CRM data during an offline session (All Accounts View).
[0024] FIG. 10C is an example of the presentation of “Accounts” CRM data during an offline session (Specific Account View).
[0025] FIG. 10D is an example of the presentation of “Accounts” CRM data during an offline session (New Account View).
[0026] FIG. 11A is an example of the presentation of “Contacts” CRM data during an offline session (Home View).
[0027] FIG. 11B is an example of the presentation of “Contacts” CRM data during an offline session (All Contacts View).
[0028] FIG. 11C is an example of the presentation of “Contacts” CRM data during an offline session (Specific Contact View).
[0029] FIG. 11D is an example of the presentation of “Contacts” CRM data during an offline session (New Contact View).
[0030] FIG. 12A is an example of the presentation of “Opportunities” CRM data during an offline session (Home View).
[0031] FIG. 12B is an example of the presentation of “Opportunities” CRM data during an offline session (All Opportunities View).
[0032] FIG. 12C is an example of the presentation of “Opportunities” CRM data during an offline session (Specific Opportunity View).
[0033] FIG. 12D is an example of the presentation of “Opportunities” CRM data during an offline session (New Opportunity View).
DETAILED DESCRIPTION OF THE INVENTION
[0034] The following detailed description will first describe the structure of an online session that may be simulated by an offline session in accordance with the invention. The structure of the offline session, itself, is then detailed. Following the description of the offline session, preparation of the client prior to conducting such offline sessions (e.g., installation and synchronization phases) is described.
Online Session
[0035] Referring to the drawings, FIG. 1 illustrates an online session between a client 100 and a remote server 200 . The client includes a local interface 110 while the remote server 200 includes a database 210 and functional logic 220 that is invoked to manipulate the data residing in the database 210 . The client 100 establishes communication channels through a network 150 that connects the client 100 to the remote server 200 .
[0036] In one environment, the network 150 used by the online session may be the Internet. In such an environment, the client 100 may be a laptop or desktop computer and the local interface 110 may be a web browser such as Internet Explorer or Netscape Navigator. The functional logic 220 at the remote server 200 may be invoked through an underlying application or specification such as a CGI program (including, for example, scripts such as Perl), Java servlet (including, for example, JavaServer Pages, or JSP, technology), daemon, service, system agent, server API solution (including, for example, ISAPI or NSAPI) or any other technique or technology known in the art. The database 210 may be a relational database management system such as Oracle or DB2. The communication channels between the local interface 110 and the remote server 200 may be governed by the HTTP protocol. For example, by selecting various options from a web page, a user transmits instructions in the form of an HTTP message through the Internet to the remote server. Upon receiving the HTTP message, the underlying program, component, or application at the remote server performs the pertinent functional logic to interact with and manipulate the data in the database in accordance with the instructions. Those skilled in the art will recognize that the foregoing general online client-server scheme is merely illustrative and that various alternatives, possibly exploiting different technologies, standards and specifications, may also be utilized to create an online session over the Internet in accordance with FIG. 1 .
[0037] In the field of customer relationship management (“CRM”), such an online client-server scheme can provide the capability to track contacts, leads and customer inquiries without needing a complex software solution on the client-side. For example, in one instance of an online CRM session, the user securely logs into the remote server by entering a username and a password through his local web browser, as shown in FIG. 2 . Once the user successfully logs into the remote server, he may be presented with an initial home page that provides access to further features and information. As shown in FIG. 3 , for example, the initial home page may provide the user with a brief synopsis of his upcoming events 310 and tasks 320 . Furthermore, the initial home page provides access 330 to further pages that enable the user the track, manage and organize other data including campaigns, leads, accounts, contacts, opportunities, forecasts, cases, and reports. Those skilled in the art will recognize that FIGS. 2 and 3 are merely examples of one way of presenting CRM information on a local interface and that there exist innumerous ways (e.g., look and feel) to present CRM information on a local interface in accordance with the online client-server scheme presented herein. Furthermore, those skilled in the art will recognize that the online CRM session described herein is merely an example of one area in which the online client-server scheme may be exploited and that there exist innumerous fields and areas in which this online client-server scheme may be exploited.
Offline Session
[0038] As shown in FIG. 4 , during an offline session, in contrast to an online session as described earlier and illustrated in FIG. 1 , the client 100 can no longer establish a communications channel through the network 150 to connect to the remote server 200 . As such, at least portions of the data from the database 210 and portions of the functional logic 220 at the remote server 200 are imported to the client 100 so that the client 100 can conduct an offline session in isolation. In FIG. 4 , at least a subset 130 of the data 210 is imported to the client 100 . Similarly, at least a subset 120 of the functional logic 220 is also imported to the client. This imported functional logic 120 is embedded into a format capable of being interpreted and performed by the local interface.
[0039] In an embodiment of an offline session in which the local interface 110 is a web browser, both the data 130 and functional logic 120 may be stored according to an open standards formatting protocol. For example and without limitation, the data 130 may be stored in a single or a series of documents in XML (Extensible Markup Language), possibly including, for example, XSL stylesheets (which are XML documents, themselves) for rendering the data into HTML documents. As is known to those skilled in the art, XML may be considered a markup language (or a specification for creating markup languages) that is used to identify structures within a document. Similarly, the functional logic 120 may be embedded in a document utilizing a markup language and may be expressed as a scripting language within the document. For example and without limitation, the functional logic 120 could be expressed as JavaScript or VBScript that is embedded in an HTML (HyperText Markup Language) document. As used herein, the term “embedded” may mean either actually embedding the JavaScript (or any other functional logic in a format capable of being interpreted and performed by the web browser) code in the HTML document, or alternatively, accessing a separate JavaScript document by, for example, providing the URL (relative or full address) of the JavaScript source code file in the HTML document. As such, when the HTML document is rendered by the web browser, depending upon certain actions taken by the user, certain portions of the functional logic 120 (e.g., JavaScript) may be interpreted and performed by the web browser. Such functional logic 120 may interact with the data 130 expressed as XML. For example and without limitation, a user may request to view portions of the data 130 on the web browser. In response to the request, by calling an XSLT (Extensible Stylesheet Language for Transformations) processor that is incorporated into the web browser (e.g., MSXML Parser) or any other comparable XSLT technology residing at the client, the functional logic 120 may access the appropriate portions of the data 130 (e.g., in XML documents) in conjunction with the appropriate XSL stylesheets, in order to transform or render such data 130 into an HTML document that is visually presented on the web browser.
Preparation of Client for Offline Session
[0040] Prior to conducting an offline session as described in the foregoing, an initial installation phase and subsequent synchronization sessions may be needed to prepare the client 100 for such an offline session. During the installation phase, an installation or setup executable may be downloaded from the remote server 200 to the client 100 . As depicted in FIG. 5 , during the installation phase 500 , the executable prepares the client for conducting an offline session by, for example and without limitation, (1) establishing a directory structure in the client's file system (Step 510 ), (2) downloading navigational markup documents with embedded functional logic (e.g., HTML files with embedded JavaScript code or HTML files and related separate JavaScript files) (Step 520 ); (3) downloading other miscellaneous installation components possibly including static HTML files, stylesheets, XSL templates, ActiveX controls, system shortcuts, local language components and, if not already available, an XML parser that may be integrated into the web browser (e.g., MSXML Parser) (Step 530 ).
[0041] Furthermore, prior to going offline, a user may synchronize the imported subset of data 130 at the client with the data residing in the database 210 . For example, if synchronization is occurring for the first time, all data residing in the database 210 that is needed for conducting an offline session may be downloaded from the database 210 to the client 100 (Step 550 ). This downloaded data may, for example, be defined and customized according to the user's criteria for conducting an offline session. In one implementation, the synchronization process may download this data as XML documents (e.g., according to data type such as accounts, contacts, opportunities, etc.). Once such XML documents are downloaded, XSL templates that are used to visually render the data (e.g., 130 in FIG. 4 ) on the web browser may be constructed at the client by utilizing the formatting instructions provided by the XML documents. Alternatively, such XSL templates might also be generated at the server and subsequently downloaded to the client. During subsequent synchronization processes prior to going offline 540 , as depicted in FIG. 5 , modified data records and data records created since the previous synchronization may be downloaded to the client (Step 560 ). Furthermore, the synchronization process 540 may also provide the opportunity to download (or modify) user customizations (e.g., XML layout information used to construct XSL templates at the client or the XSL templates themselves) for the visual representation of data and other information on the web browser (Step 570 ). Similarly, upon re-establishing a connection with the remote server 200 , the user may also desire to conduct a synchronization process 580 in order to upload any modified or newly created data records to the remote database 210 (Step 590 ). In one implementation of the synchronization process, the communication channel between the client 100 and the remote server 200 may be established through the HTTP protocol using XML-RPC and a related HTTP/HTTPS server based XML API. Those skilled in the art will recognize that there are alternative synchronization processes other than the one presented in FIG. 5 that may be conducted in accordance with the present invention. For example and without limitation, all synchronization processes, regardless of whether the subsequent activity is an offline session or the re-establishment of an online connection, may simultaneously download modified and newly created data records from the server database to the client as well as upload modified and newly create data records from the client to the server database. Additionally, those skilled in the art will recognize that any variety of techniques and models known in the art may be used implement the synchronization process in order to maintain consistency and coherency while accessing data (e.g., atomic, sequential or causal consistency, etc.).
[0042] FIG. 6 illustrates one embodiment of a process for initiating and conducting an offline CRM session. As depicted, in this embodiment, an initial installation process should be conducted before an offline session can begin (e.g., Steps 610 , 510 , 520 , 530 ). After installation, a user may initiate an offline session by opening an HTML page downloaded to the client during the installation phase (Step 620 ). While still online, the user may then synchronize local client data with the remote database before going offline (Step 630 and expanded in Steps 632 , 634 , 550 , 560 , 590 ). As shown in FIG. 6 , this may involve downloading data from the remote server (Step 550 ) as well as uploading data to the remote server (Step 590 ), and if necessary, an initial download of all offline session data (Step 550 ). As previously discussed, one implementation of such downloading and uploading may be implemented through HTTP communications channels using XML-RPC. Once synchronization is complete, the user may go offline and manipulate, view, and modify his customer relationship data by selecting from various options through the web browser (Step 640 ). For example and without limitation, the user may view his calendar, tasks, and activities (Step 642 ). Additionally, data may be organized into certain categories such as accounts, contacts, and opportunities. The user may be able to maneuver through the web browser to access, edit, create, delete, or otherwise modify data within these categories (Steps 642 , 644 , 646 , 648 ).
[0043] FIGS. 7 to 12D represent examples of the local interface 110 as a web browser that may serve as visual examples for certain steps in the flowchart of FIG. 6 . For example, FIG. 7 illustrates a login interface to access the remote server to initiate a synchronization corresponding to 632 of FIG. 6 . Similarly, FIG. 8 illustrates the synchronization process of downloading modified and newly created records from the remote database as in 560 of FIG. 6 (and possible uploading of any modified or newly created records to the remote database as in 590 of FIG. 6 ). Corresponding to Step 642 in FIG. 6 , FIG. 9A illustrates one example of an offline home page and FIGS. 9B to 9E illustrate various other alternative “Home” views that may be accessed by the user during an offline session. Similarly, corresponding to Step 644 in FIG. 6 , FIGS. 10A to 10C illustrate various views of data organized into an Accounts category. Corresponding to Steps 646 and 648 in FIG. 6 , FIGS. 11A to 11D illustrate various views of data organized into a Contacts category and FIGS. 12A to 12D illustrate various view of data organized into an Opportunities category, respectively.
[0044] The various embodiments described in the above specification should be considered as merely illustrative of the present invention. They are not intended to be exhaustive or to limit the invention to the forms disclosed. Those skilled in the art will readily appreciate that still other variations and modifications may be practiced without departing from the general spirit of the invention set forth herein. For example and without limitation, those skilled in the art will recognize that there exist alternative proprietary technologies, languages and open standards (e.g., other than JavaScript, XML, XSLT, XML-RPC, HTML, HTTP, etc.) that may be practiced in the context of the Internet and World Wide Web in accordance with the invention set forth herein. Furthermore, while much of the foregoing discussion has been described in the context of the World Wide Web and the Internet (e.g., local interface 110 is a web browser), those skilled in art will recognize that the invention disclosed herein may be implemented in other network environments as well. Similarly, while much of the foregoing discussion utilized the CRM area as an example, those skilled in the art will also recognize that other fields and areas may exploit the invention disclosed herein. Therefore, it is intended that the present invention be defined by the claims that follow.
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A method and system for conducting an offline session simulating an online session between a client and server in a network environment. The client imports data and functional logic from the server prior to going offline. The imported functional logic is embedded into a format or document that is capable of being interpreted and performed by the local interface at the client that is used to interact with server during an online session. Whether offline or online, the user utilizes the same local interface at the client to transmit instructions to the functional logic in order to manipulate the data. In an offline session, such instructions cause the imported and embedded functional logic to execute, thereby manipulating the data that is imported at the client. Known synchronization methods may also be used in order to maintain consistency and coherency between the imported data at the client and the database at the server.
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This application claims priority benefits from French Patent Application No. 04 11349 filed Oct. 25, 2004.
BACKGROUND OF THE INVENTION
The invention relates to a method for operating a motorized screen device comprising a screen windable on a winding tube whose angular position is measured by a sensor, and at least one means of latching of the free end of the screen defining a position termed latched position in the direction of winding, the latching being activated in this direction if the free end of the screen previously reaches at least one position of reversal, to which corresponds for the unwinding a value of angular position of the winding tube termed the position of reversal of rotation, situated beyond the latched position in the direction of unwinding of the screen. The invention also relates to a motorized screen device for the implementation of such a method.
DESCRIPTION OF THE PRIOR ART
Known screen devices comprise a windable element fixed on the one hand to a winding tube around which the latter is wound and on the other hand to a rigid bar termed the load bar, the load bar generally being guided by its ends in rails situated on either side of an opening to be masked. Screen devices also comprise a means of latching making it possible to maintain the load bar in a determined position so as to prevent the latter from lifting or banging under the actions of the wind and to prevent the windable element from flapping in the wind.
Usually, during the unwinding of the windable element, the load bar enters the latching means and pursuant to a reverse movement, that is to say to an unwinding movement, locks in the latching means. To unlatch and open the screen again, it is necessary firstly to displace the screen in the direction of unwinding as far as a certain position before being able to wind up the screen.
These various displacements may be performed manually, that is to say by the action of forces caused by the user and applied to the windable element, or be performed in a motorized manner, that is to say by the action of forces caused by an actuator and applied to the windable element.
In the latter case, the actuator is generally placed in the winding tube and responds to commands emanating from a user by way of a control interface. The actuator comprises electrical or electronic means of managing the movement of the screen as a function of the orders received and as a function of events detected. These electrical or electronic means may, in order to do this, operate jointly with sensors of position, of torque or of displacement time. Together, these means constitute a control unit.
Such devices are described for example in the following documents: FR 2 573 551, EP 1 319 795 and JP 2001-173347.
Application FR 2 573 551 discloses a motorized shutter device comprising a means of latching and a load bar whose ends slide in glideways. A first position and a second position of the load bar are tagged and the passage of the load bar through these positions causes the toggling of switches.
The first position corresponds to a top position of reversal of direction, that is to say to a position in which, on entering the latching means, a reversal of the direction of displacement causes locking of the shutter and more particularly locking of the rotation of the slats of the shutter.
The second position corresponds to a bottom position of arrest in the latching means. These positions are defined by a mechanical counting device with manual adjustment and are managed as end-of-travel positions.
Document JP 2001-173347 describes a motorized shutter device comprising latching means. The passage of the load bar of the device to a height level with these latching means causes the toggling of the latching means. The movement of the shutter is continued as far as a bottom position, then reversed. The toggled latching means then lock the opening movement. The latching position can be sensed by sensors, the position of reversal of movement by a torque detection.
Patent application EP 1 319 795 discloses a method of learning the positions of a latching device making it possible to automatically manage the movements of a windable element comprising a load bar as a function of the orders received from the user. The learning method defines several significant positions. A first position corresponds to the top end of travel of the windable element, a second position corresponds to the so-called latching position, a third position corresponds to the position in which the movement of the screen must be reversed so as to activate the latching means and a fourth position corresponds to the so-called unlatching position below which it is necessary to move so as to unlatch the windable element.
During a down movement, the load bar of the windable element leaves from the first position and goes down toward the third position situated in the latching means. In this third position, the movement of the windable element is stopped and then reversed until the second position is reached. In this position, the load bar is locked in the latching means and the up movement cannot be continued. At this moment, the windable element is stressed and may not be lifted or inflated by the wind.
To unlatch the windable element, it is then necessary to unwind the element until a fourth position before being able to reverse the displacement, that is to say wind the element up.
Thus, to configure the device, the installer must displace the element until the load bar has entered the latching means in a position lying between the second and fourth position. There, the installer must instruct a reversal of the direction of the displacement of the load bar so as to direct it toward the second position and determine, by overtorque detection, this position before recording it automatically. The third and fourth positions are determined subsequently. The description remains very vague however on the manner of determining these positions.
The latching means currently used are of small size, thus the distances separating the second, third and fourth positions are reduced. This characteristic is a problem for the implementation of the method described previously. Specifically, on account of these small distances, it is very difficult for the installer, during the installation of the device, to bring the windable element directly into a position lying between the second and the fourth position. Consequently, the installer very often has to repeat a displacement of the windable element in the down direction as far as the latch in order to succeed in stopping the screen in a desired position. Specifically, if the fourth position is passed, it is necessary to return to a starting position situated between the first and the second position to be able to configure the device.
Additionally, more and more latching means of the “open” type are being used. This type of latching means makes it possible to allow the load bar to pass freely through it when no reversal of direction of displacement is instructed. Consequently, these latching means may be installed anywhere along the guideways of the load bar and make it possible to define intermediate latching positions. Thus, the windable element can for example be latched midway along its travel so as to cover only the upper part of the opening equipped with it.
With respect to the prior art cited in this document, the method of learning makes it possible to determine the positions without having to define the displacements between the first position and the fourth position, via the second and third positions.
SUMMARY OF THE INVENTION
The aim of the invention is to provide a method for operating a motorized screen device making it possible to alleviate the drawbacks cited and making it possible to improve the methods of operation known from the prior art. In particular, the invention proposes a method of operation making it possible to make easier the procedures for configuring and adjusting the motorized screen device and to reduce the time required to complete them. The invention proposes in particular to make easier the procedures for defining the positions of the means of latching of the device.
The method of operation according to the invention is one wherein, in a mode of configuration of the latching of the screen, the installer proceeds merely to record the value of a chosen angular position, termed the recorded rotation reversal position, this position being situated at the level of or beyond the position of reversal of rotation, in the direction of unwinding of the screen.
Various modes of execution of the method are defined by the dependent claims 2 to 8 .
The motorized screen device according to the invention comprises a screen windable on a winding tube whose angular position is measured by a sensor, and at least one means of latching of the free end of the screen defining a position termed latched position in the direction of winding, the latching being activated in this direction if the free end of the screen previously reaches at least one position of reversal, to which corresponds for the unwinding a value of angular position of the winding tube termed the position of reversal of rotation, situated beyond the latched position in the direction of unwinding of the screen. It is characterized in that it comprises hardware and software means for the implementation of the method of operation defined previously.
The motorized screen device may comprise a screen drive torque sensor.
DESCRIPTION OF THE DRAWINGS
The appended drawing represents an embodiment of a motorized screen device according to the invention and various modes of execution of the method of operation according to the invention.
FIG. 1 is a diagrammatic view of a motorized screen device making it possible to implement the method of operation according to the invention.
FIG. 2 is a diagrammatic detail view of a motorized screen device at the level of one of its latching means.
FIG. 3 is a diagram illustrating a process of a first mode of execution of the method of operation according to the invention.
FIG. 4 is a diagram illustrating a process of a second mode of execution of the method of operation according to the invention.
FIG. 5 is a diagram illustrating a process of a third mode of execution of the method of operation according to the invention.
FIG. 6 is a diagram illustrating the correspondences between angular positions of a winding tube and positions of the free end of a screen.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A motorized screen device 1 is represented in FIG. 1 . This device comprises a windable element 2 linked at one of its ends to a winding tube 3 and at the other of its ends, called the free end, to a load bar 4 whose ends are guided by guiding rails disposed in a building on either side of an opening that the windable element is intended to cover.
The displacements of the windable element 2 or screen are controlled by the rotational displacements of the winding tube 3 . A tubular gear motor disposed inside the winding tube 3 allows the latter to be driven. The movements of the gear motor are controlled by a control unit 7 linked to the gear motor, to sensors 10 , 12 and to a user interface 5 with which a user can control the movements of the windable element. The device comprises a sensor 12 of the angular position of the winding tube 3 and can also comprise a torque sensor 10 for sensing the torque exerted by the gear motor so as to detect obstacles and/or the ends of travel and a sensor of position of the load bar 4 . The user interface 5 can be linked to the control unit 7 by wire-based or non-wire-based communication means (for example by RF waves or by infrared rays). The control interface 7 comprises in particular a logic processing unit 8 and a memory 9 .
The windable element may in particular consist of a closure, shading or solar protection element. It may in particular consist of a fabric. The winding tube is preferably mounted above the opening that the windable element is intended to cover. The windable element is preferably wound in a casing 11 intended to protect it.
To simplify the description, the screen is considered to unwind downwards, in particular under the effect of its own weight. Other configurations are obviously possible.
A first position P 1 of the load bar or of the free end of the element corresponds to a position of complete opening of the windable element. To this position corresponds an angular position D 1 of the winding tube 3 , as represented in FIG. 6 .
Along the guiding rails disposed on either side of the opening, the device comprises latching means 6 . The latching means cooperate with the ends of the load bar. These latching means determine, as represented in FIG. 2 , a second position P 2 of the load bar, a third position P 3 of the load bar and a fourth position P 4 of the load bar. The second position P 2 is a so-called latched position in which the windable element is locked, corresponding to a latched angular position D 2 of the winding tube 3 . The third position P 3 is a so-called reversal position. When the load bar goes past this position P 3 in the direction of unwinding of the element and when subsequently a winding movement of the element is instructed, the screen is again locked, the load bar being in position P 2 and the winding tube in position D 2 . This position P 3 corresponds to a reversal angular position D 3 of the winding tube 3 . The fourth position P 4 is a so-called exit position below which the load bar having been latched must come so that the windable element can again be wound until it reaches its position of total opening P 1 . This position corresponds to an exit angular position D 4 of the winding tube 3 .
The position P 4 is a lower position than the position P 3 , this position P 3 being lower than the position P 2 .
During the latching configuration, a position PM of the load bar must be defined as must the corresponding position DM of the winding tube 3 . These positions PM and DM must be chosen and recorded by the installer. The position PM is termed the recorded reversal position and the PM is termed the recorded reversal angular position DM.
The value dM of the position DM is used in the mode of use of the motorized screen. Specifically, when the user sends an order for closure and for latching of the load bar in position P 2 to the screen device (in the closed position), the screen device firstly executes an action of rotation of the winding tube 3 in the direction of unwinding of the screen, then, when the position sensor 12 detects that the winding tube has reached the position DM (signifying that the load bar is in position PM), executes an action of stoppage of the movement of rotation of the winding tube. The screen device then immediately executes an action of rotation of the winding tube in the direction of winding until the position sensor detects that the tube has reached the position D 2 (signifying that the load bar is locked in position P 2 ).
The load bar may furthermore cross the latching means in the down direction as in the up direction without being latched if no reversal of its direction of displacement occurs between positions P 3 and P 4 .
The positions PM must lie inside the means of latching in a zone in which a reversal of direction of displacement of the load bar from a down displacement to an up displacement causes the latching of the load bar, that is to say anywhere between positions P 3 and P 4 . Outside of this zone, the reversal of direction of displacement of the load bar produces no particular effect.
Various types of latching means operating according to this principle may be used. It is in particular possible to use latching means such as those described, with reference to FIG. 3 , in the passage from line 41, column 2, to line 42, column 3 of patent application EP 1 270 865 A2. It is also possible to use latching means such as those described in patent application EP 1 223 262 A1. The contents of these two applications are incorporated by reference into the present application.
A first process for configuring the motorized screen device is represented in FIG. 3 and defines a first mode of execution of the method of operation according to the invention.
In a first step 100 , the installer instructs by way of the user interface a down movement of the load bar, that is to say an unwinding movement of the windable element, or an up movement of the load bar, that is to say a winding movement of the windable element until the load bar is brought into the latching means and more precisely into the zone in which a reversal of the direction of displacement of the load bar, from a down movement to an up movement, causes a locking of the bar. This zone may be indicated by markings on the guiding rails or on the latching means, the load bar coming opposite these markings when it is in said zone. Having regard to this zone's restricted nature related to the character of the latching means, the installer may be compelled to attain this zone by trial and error, without however being compelled to re-emerge from the latch. This trial and error then corresponds to fine adjustments, through small down and up movements of the load bar.
Once the load bar is in the sought-after zone, in a step 110 , the installer manually records the value dM of the angular position DM of the winding tube corresponding to the instant position PM of the load bar. This value dM is recorded in a memory of the motorized screen device control unit. The recording is instructed for example by a particular action on the user interface or by pressing a particular button of the user interface.
In a step 120 , triggered automatically following the recording of the value dM, energization of the gear motor is instructed causing the winding of the windable element and consequently the raising of the load bar. This step could also follow an action by the installer.
In a step 130 , the load bar reaches the position P 2 in which it is locked by the latching means. This position is detected by the torque sensor and the energy supply to the gear motor is cut. The value d 2 of the angular position D 2 of the winding tube corresponding to the position P 2 of the load bar is automatically recorded in memory in the motorized screen device control unit. The value d 2 recorded may correspond to a position slightly lower than the position of locking of the load bar so that once in the mode of use, when a user instructs the closure of the screen, the load bar does not come into its locking position, exerting significant stresses on the latching means.
In a step 140 , triggered automatically following the recording of the value d 2 , energization of the gear motor is instructed, causing the unwinding of the windable element and consequently the descending of the load bar. This step could also follow an action by the installer.
In a step 150 , the load bar reaches the unlatching position P 4 . This so-called unlatched position may be detected by a detection of variation of the torque, the value d 4 of angular position D 4 of the winding tube corresponding to the position P 4 is automatically recorded in a memory of the motorized screen device control unit. When this position is detected, a stoppage of the gear motor, by cutting off of the energy supply, is instructed. The position P 4 may also be determined by knowing the position P 2 and by knowing the type of latching means used. The type of latching means used may be stored in memory during installation or during the manufacture of the screen device. In the case where this position may be determined with these data, the value d 4 is recorded in memory with the value d 2 in step 130 and, during step 150 , only a cutting off of the energy supply to the gear motor is instructed.
In a step 160 , triggered automatically following step 150 , an energizing of the gear motor is instructed, causing a reversal of direction with respect to the last direction of displacement and hence the winding of the windable element. Consequently, the load bar rises back to a position higher than the position P 2 .
In a step 170 , triggered automatically following step 160 , two energizings of the gear motor of short duration and in different directions are instructed, causing short back and forth movements of the load bar. These movements make it possible to acknowledge the recordings performed.
The device can then toggle into the mode of use.
The drawback of this process is that the confirmation signal occurs a relatively long time after the recording by the installer of the value dM corresponding to the position PM.
A second process for configuring the motorized screen device is represented in FIG. 4 and defines a second mode of execution of the method of operation according to the invention.
This process of configuration makes it possible to simplify the installation while assuring the installer that he has carried out the necessary actions properly.
In a first step 200 , the installer instructs by way of the user interface a down movement of the load bar, to a position P 5 lying below the unlatched position P 4 .
In a second step 210 , the user instructs by way of the user interface an up movement of the load bar, until the latter is brought into the latching means and more precisely into the zone in which a reversal of the displacement of the load bar, from a down movement to an up movement, causes a locking of the bar. Having regard to this zone's restricted nature related to the character of the latching means, the installer may be compelled to attain this zone by trial and error. This trial and error then corresponds to fine adjustments of position, by small up and down movements of the load bar.
Once the load bar has halted in the sought-after zone, in a step 220 , the installer manually records the value dM of angular position DM of the winding tube corresponding to the position PM of the load bar. This value dM is recorded in a memory of the motorized screen device control device. The recording may be instructed for example by a particular action on the user interface or by the pressing of a particular button of the user interface.
In a step 230 , triggered automatically following step 220 , energizing of the gear motor is instructed, causing the winding of the windable element and consequently the raising of the load bar to a position higher than the position P 2 .
In a step 240 , triggered automatically following step 230 , two energizings of the gear motor of short duration and in different directions are instructed, causing short back and forth movements of the load bar. These movements make it possible to very rapidly acknowledge that the recording of the value dM has been performed.
The device can then toggle into the mode of use, the other positions P 2 and P 4 not necessarily having to be learnt in the configuration mode.
Following the recording performed in step 110 or in step 220 , the control unit itself determines which procedure has to be the next to be performed. This procedure may depend on several criteria, in particular:
if the last displacement of the windable element was a down displacement, then the control unit causes a reversal of the direction of displacement and, if the last displacement of the windable element was an up displacement, then the control unit causes a new up movement, if the load bar is locked in the latching means, in a time window following the recording of the value dM corresponding to the position PM, the control unit deduces therefrom that it is dealing with the position P 2 , on particular actions performed for the configuration according to the first process or according to the second process, on the order given by the installer following the recording of the value dM.
The recording of the value of the position of reversal by the installer therefore makes it possible to configure the device in a simple manner, and in particular to bring the device into the position of reversal possibly by fine adjustments, from a position short of or beyond the latch.
A third process for configuring the motorized screen device is represented in FIG. 5 and defines a third mode of execution of the method of operation according to the invention, this mode being applicable to the latching means of “closed” types that is to say latching means below which the load bar cannot descend.
In a first step 300 , the installer instructs by way of the user interface a down movement of the load bar, that is to say an unwinding movement of the windable element until the load bar is brought into the latching means in the position PM corresponding, having regard to the type of latching means, to a position of locking of the load bar. In this position, the windable element may however continue to be unwound and then wound, as ordered by the installer, as represented in step 310 , so as to reach a position in which the load bar is in the position PM and in which the windable element is slightly stressed (especially in the case when the windable element is made of fabric).
Steps 320 to 380 of this mode of execution are identical to steps 110 to 170 of the first mode of execution.
The motorized screen device may then toggle into the mode of use.
The motorized screen device according to the invention may exhibit in memory various algorithms corresponding to the various configuration processes. The choice of the process used can for example revert to the installer. The existence of these various processes allows the installer to use the process making it possible to effect the configuration in the most effective possible manner.
In the mode of use, when an order to close the screen is instructed, the windable element is unwound until the load bar reaches the position PM, then the screen is wound so as to reach the position P 2 . If the value d 2 corresponding to the position P 2 is already recorded, the winding of the windable element is stopped as soon as the load bar reaches this position and, if the value d 2 corresponding to the position P 2 is not yet recorded, the winding of the windable element is instructed until the torque sensor detects a torque higher than a determined value signifying that the position P 2 has been reached. In the latter case, the position P 2 can then be recorded in memory. The load bar then remains locked in position until another order to move the screen is instructed.
When an order to wind the windable element is instructed, the windable element is firstly unwound until the load bar reaches the position P 4 . If the value d 4 corresponding to the position P 4 is already recorded, the unwinding of the windable element is stopped as soon as the load bar reaches this position and, if the value d 4 corresponding to the position P 4 is not yet recorded, the unwinding of the windable element is instructed until this position is detected automatically, for example if the torque sensor detects a decrease in load signifying that the position P 4 has been reached. In the latter case, the value d 4 corresponding to the position P 4 can then be recorded in memory. The windable element can then be wound freely until the screen is fully opened or until a defined position.
If the motorized screen device comprises several means of latching at various locations on the guiding rails, making it possible to define intermediate positions, provision may be made such that if the user instructs a stoppage of the movement of the windable element while the load bar is in proximity to latching means, movements of winding and of unwinding are automatically performed, after this stop instruction, so as to lock the load bar in said latching means.
In the user mode, the recordings of the values d 2 , dM and d 4 corresponding to the positions P 2 , PM and P 4 may be regularly updated following, for example, a certain number of displacements of the load bar so as to take account of dispersions that may occur during use, in particular at the level of the play in the windable element's kinematic drive chain. In this case, the position P 2 is determined by virtue of the torque sensor, the position PM is deduced from the position P 2 (for example through a mathematical relation depending on the type of latching means used or the values previously recorded) and the position P 4 is determined by virtue of the torque sensor or is deduced from the position P 2 (for example through a mathematical relation depending on the type of latching means used or the values previously recorded).
The latching means used may also be of the type in which the crossing of the latching means by the load bar in a first direction does not bring about locking and in which the crossing of the latching means by the load bar in a second direction brings about locking. To unlatch the load bar, a slight movement of the latter in the first direction followed by a movement in the second direction is necessary.
The bottom end-of-travel latching means are usually not of this type. Consequently, the manner of operation of the latching means with which the motorized screen device is equipped, may be different.
The various described modes of execution of the method may also be applied in the case of electromechanical latches operated as a function of the positions and/or movements of the free end of the screen.
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The method applies to a motorized screen device comprising a screen windable on a winding tube, and at least one means for latching the free end of the screen defining a position termed latched in the direction of winding, the latching being activated in this direction if the free end of the screen previously reaches at least one position of reversal, to which corresponds for the unwinding a value of angular position of the winding tube termed the position of reversal of rotation, situated beyond the latched position in the direction of unwinding of the screen. According to the method, in a mode of configuration of the latching of the screen, the installer proceeds merely to record the value of a chosen angular position, termed the recorded rotation reversal position, this position being situated at the level of or beyond the position of reversal of rotation, in the direction of unwinding of the screen.
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BACKGROUND OF THE INVENTION
Technical Field
This invention relates to a self-erecting signal device. More particularly, it relates to a self-erecting signal device which is particularly suited for signaling spills or spots on floors so as to serve as a warning.
Inflatable signaling devices are well-known. These are disclosed in U.S. Pat. Nos. 2,762,327; 3,113,551; 3,250,241; 3,707,320; 3,720,181 and 3,892,081.
Self-inflatable enclosures are disclosed in U.S. Pat. Nos. 4,929,214 and 5,941,752.
Fluid absorbing mats are disclosed in U.S. Pat. Nos. 5,270,089; 5,506,040; 5,549,945; 5,597,418 and 5,834,104.
The prior art does not provide a self-erecting signaling device. Neither does it provide a self-erecting signaling device which is adaptable for use with a liquid absorbing mat.
There is a need for a self-erecting signaling device to indicate spills on a floor. These occur frequently in stores and particularly those which provide products which when dropped on a floor result in a liquid or slippery substance. This is a hazardous condition for shoppers as falls can occur. Not only is a self-erecting signaling device beneficial, it is even more useful if it is combined with an absorbing material which can absorb the spilled material.
The objects of the invention therefore are:
a) Providing a self-erecting signaling device.
b) Providing a self-erecting signaling device which is easily activated.
c) Providing a self-erecting signaling device of the foregoing type which is simple in construction and economical to produce.
d) Providing a self-erecting signaling device of the foregoing type which includes a fluid absorbing feature.
e) Providing a self-erecting signaling device of the foregoing type which can also include a cleaning function.
f) Providing a self-erecting signaling device of the foregoing type which is compact in design.
SUMMARY OF THE INVENTION
The foregoing objects are accomplished and the shortcomings of the prior art are overcome by the self-erecting device of this invention which in one embodiment includes a signal member, and an inflatable member. The signal member is connected to the inflatable member. A self-contained expandable member is present within the inflatable member, the inflatable member constructed and arranged to be inflated by the self-contained expandable member. A base member is constructed and arranged to support the outer member.
In another embodiment, the self-erecting device includes a base member constructed to rest on a surface. There is a gas generating member and an inflatable member in fluid communication with the gas generating element. A signal element is erected by the inflatable member.
In another embodiment, the base member includes an absorbent member constructed and arranged to absorb liquid and spills on a surface.
In a preferred embodiment the inflatable member is gas impervious material and of a tubular configuration when inflated, and the expandable member includes a first material and second material which when reacted produce a gas, the materials being separated by a breachable member.
In still another embodiment, the expandable member includes an expandable system comprised of a liquid and an expandable member which expands when contacted with the liquid, the first and second members being separated by a breachable member to provide contact between the liquid and the expandable member.
In a most preferred embodiment, the self-erecting device includes a base member, a signal member, a self-contained expandable member, and a gas impervious inflatable member having opposing ends, the gas impervious inflatable member connected at opposing ends to the signal member and the base member. The expandable member is positioned in the gas impervious inflatable member whereby when the expandable member is activated, the gas impervious member expands to an elevated position, and in turn expands the signal member to an elevated position.
In yet another embodiment, there is a combined cleaning and self-erecting device which includes a cleaning member including a pad of absorbent materials. There is a cleaning material contained in a breachable container, the breachable container is connected to the pad. A self-erecting device is connected to the pad.
In still another embodiment, there is a self-erecting warning device which includes a first expandable member and a second expandable member for expanding the first expandable member. The second expandable member is the sole means for expanding the first expandable member and there is a liquid source constructed and arranged to provide a liquid to expand the second expandable member.
There is also provided a method of cleaning up a spill on a floor while signaling its location which includes placing an absorbent member on the spill. The absorbent member is connected to a self-erecting device. The self-erecting device is activated to signal the location of the spill.
In a preferred manner the method includes employing a self-erecting device composed of an inflatable member having an expandable member having a first member composed of a liquid and a second member composed of an expandable member which expands when contacted with the liquid, the first and second members being separated by a breachable member. The breachable member being broken by adequate force to provide contact between the liquid and the expandable member.
In yet another preferred manner, a method of cleaning up a stain on a surface while signaling its location is provided which includes placing a pad member connected to a self-erecting device, the pad member connected to a sachet containing a stain removing substance on a stain and activating the self-erecting device and releasing the stain removing substances from the sachet and allowing the pad member saturated with the stain removing substance and attached to the self-erecting device to remain on the surface and alternatively repeating the above steps until the stain is removed.
These and still other objects and advantages of the invention will be apparent from the description which follows. In the detailed description below, a preferred embodiment of the invention will be described in reference to the full scope of the invention. Rather, the invention may be employed in other embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of the self-erecting device of this invention;
FIG. 1A is a side view of an inflatable member employed in the self-erecting device of FIG. 1 ;
FIG. 1B is a view similar to FIG. 1A illustrating the activation of the inflatable member;
FIG. 2 is a perspective view of the self-erecting device of FIG. 1 in the erected state;
FIG. 3 is a view similar to FIG. 2 with a portion broken away to show the inflatable member;
FIG. 4 is a view similar to FIG. 1 showing an alternative embodiment;
FIG. 5 is a view similar to FIG. 2 showing another embodiment;
FIG. 6 is a view similar to FIG. 1 showing another embodiment;
FIG. 7 is a view similar to FIG. 3 showing the FIG. 6 embodiment in an erected state;
FIG. 8 is a view similar to FIG. 1 showing another embodiment;
FIG. 9 is a view similar to FIG. 3 showing the FIG. 8 embodiment in an erected state;
FIG. 10 is a view similar to FIGS. 1A and 1B showing a preferred embodiment;
FIG. 11 is a sectional view taken along line 11 — 11 of FIG. 10 ;
FIG. 12 is a view similar to FIG. 1 showing a preferred inflatable and expandable member for the self-erecting device; and
FIGS. 13 and 14 are side views of the preferred inflatable and expandable member shown in FIG. 12 .
DETAILED DESCRIPTION
Referring to FIG. 1 , the self-erecting device of this invention generally 10 includes a flexible signal element or member 12 attached to a base member 17 . Signal member 12 is composed of a plastic sheet which is preferably high density polyethylene. It is a flexible, expandable, pyramidal blanket which overlies the base member 17 . It is of a pyramidal configuration when inflated. An inflatable member 14 is connected to the signal member 12 as well as the base member 17 . Base member includes a lower fabric covering 18 and an upper fabric covering 18 a . The lower fabric covering 18 and upper fabric covering 18 a are composed of a nonwoven fabric comprised of 75% PET and 25% cellulose, Grade 12124 from Ahlstrom Fiber Composites. An absorbent core layer 19 is composed of a cellulose/super absorbent polymer composite core material from Gelok International Corp. as Gelok(r) 500/50 composite. It is entrapped in the nonwoven matrix of the fabric coverings 18 and 18 a.
An expandable member 16 is placed inside the inflatable member 14 . This is seen in FIGS. 1A and 1B . The inflatable member 14 is of a tubular configuration and contains two sachets 20 and 22 . The inflatable member 14 is composed of a flexible polypropylene gas impervious plastic material as are the sachets 20 and 22 . In the instance of the sachets, they contain components which when mixed together produce a gas. For example, sachet 22 can contain a carbonate or bicarbonate powder and sachet 20 an acid solution such as citric. These sachets 20 and 22 are constructed so they are breachable when a force is imposed so as to result in a mixing of the acid with the powder and produce carbon dioxide gas and provide an expandable member 16 . This gas generating system is indicated in FIG. 1B with the carbon dioxide being indicated at 23 .
In the following embodiments of FIGS. 4–9 , the same parts are indicated with the same numbers as indicated in FIGS. 1–3 .
The FIG. 4 embodiment generally 40 is similar to embodiment 10 except that it additionally includes a frangible pad 34 which contains a carpet stain remover or a remover of stains on hard floors such as stone or terrazzo. The preferred stain remover is specific for the type of stain, either water-borne or oily. For water-borne spots and stains, the preferred stain remover is a 1% solution of sodium lauryl sulfate in water. For oily stains, the preferred stain remover is mineral spirits. The pad would be composed of a material similar to the sachets 20 and 22 .
FIG. 6 illustrates still another embodiment generally 50 . In place of the previously described tubular inflatable member 14 , there is a latex balloon 52 containing frangible sachets 54 and 55 which contain the previously described acid and powder.
FIGS. 8 and 9 show yet another embodiment generally 60 . In place of the previously described tubular inflatable member 14 and the balloon 52 , there is a sponge 62 with a frangible water sachet 64 .
FIGS. 10 and 11 illustrate another embodiment generally 78 with an inflatable member 80 and expandable member 81 . In this instance, there is an inner sachet 84 containing water 86 and the outer expandable member 81 providing a compartment or sachet 82 for a powder 88 composed of sodium bisulfate and sodium carbonate. A pin hole 91 is located at one end of the sachet 82 for the purpose as later explained in the Operation. A precut or preweakened portion 92 is provided in the inflatable member 80 the purpose of which will also be later explained.
The preferred material for fabricating the inflatable member 80 is polypropylene. The expandable member 81 or sachet 82 is composed of high density polyethylene and sachet 84 is composed of low density polyethylene.
In a preferred manner, sachet 84 is heat sealed along its edges such as at 83 and 85 as well as at 87 where it is in turn sealed to sachet 82 . It will be recognized that in the instance of seals 83 and 84 , they are designed so that sachet 84 can be broken with hand or foot force to allow water 86 to escape and mix with powder 88 . Sachet 82 is in a like manner sealed in a tubular manner along edges 89 and 90 as well as at 94 where it is sealed to sachet 84 as well as inflatable member 80 . It will be seen that the inflatable member 80 is in turn sealed in tubular manner along its edges 95 , 96 and 97 .
Inflatable member 80 is heat sealed to the outer member 12 and base member 17 at its opposing ends such as along seals 96 and 97 .
It will be recognized that inflatable member 14 as well as sachets 20 and 22 are sealed in a tubular manner such as previously described for inflatable member 80 and sachets 82 and 84 . It is not necessary for the sachets 20 and 22 to be connected to the inflatable member 14 .
FIGS. 12–14 illustrate a preferred embodiment generally 120 of an inflatable member 100 and 101 and an expandable member. In both instances, sachets 102 and 103 are similar to previously described sachet 82 and are heat sealed along edges 104 , 105 and 106 . Sachets 102 and 103 are in turn sealed to inflatable members 100 and 101 in conjunction with seals 106 . Unlike inflatable member 80 , inflatable members 100 and 101 are blown in a tubular manner and sealed along edges 107 and 108 . The preferred material for producing inflatable members 100 and 101 is polypropylene, whereas the preferred material for producing sachets 102 and 103 is a polyethylene terephthalate/polyethylene laminate.
Sachet 102 of inflatable member 100 is filled with an acid solution 109 composed of citric acid and water. A carbonate base material 110 such as sodium carbonate is loosely placed in inflatable member 100 . Inflatable member 101 is similar to inflatable member 100 except for the materials in the sachet 103 and in the inflatable member 101 . In place of the acid solution 109 , water 111 is sealed in sachet 103 and an acid/carbonate powder blend 112 such as sodium bisulfate and sodium carbonate is placed in inflatable member 101 . The acid solution 109 and base material 110 , as well as the water 111 in combination with the acid/carbonate powder blend 112 provide expandable members for the inflatable members 100 and 101 .
Referring to FIG. 12 , inflatable member 100 is heat sealed to and centrally positioned with respect to the base member 17 . At the opposite end inflatable member 100 and sachet 102 are heat sealed to the outer or signal member 12 by heat sealing a portion of the edge 107 or tag to the signal member 12 . Inflatable member 100 is centrally positioned with respect to signal element 12 . Inflatable member 101 is connected to base member 17 and signal element 12 in a similar manner.
Operation
A better understanding of the self-erecting devices of the invention will be had by a description of their operation. Referring to embodiment 10 , it will be supplied in a collapsed condition as shown in FIG. 1 . When a liquid spill is detected as indicated at 26 in FIG. 2 , self-erecting device 10 is placed over the spill 26 and a force exerted on it such as by a foot. The force should be sufficient to fracture the sachets 20 and 22 and cause the citric acid solution and the carbonate powder to react. This is depicted in FIG. 1B with the carbon dioxide gas 23 evolving. As the gas evolves, it fills tubular inflatable member 14 causing it to rise and assume a pyramidal position as shown in FIG. 3 . The inflatable member 14 functions in a manner similar to the center pole in a tent. It is connected centrally to base member 17 such as at 66 and at the inside of peak or apex 68 of the erected outer member 12 . When placed over spill 26 in the erected position as seen in FIG. 2 , it will serve as a warning device with the indicia 24 . At the same time, the absorbent layer 19 in base member 17 absorbs the liquid spill 26 . The absorbent layer 19 can be saturated with the spill.
Embodiment 40 functions in a similar manner as described for embodiment 110 except that this device 40 is designed for use on carpet spills or spills on stone or terrazo floors. In this instance, device 40 is placed over the spill and activated by the force of one's foot. This simultaneously activates the sachets 20 and 22 as well as sachet 34 which contains the stain remover.
Embodiments 50 and 60 function in a similar manner as previously described for embodiment 10 . In embodiment 50 , the two sachets 54 and 55 are similar to sachets 20 and 22 and when fractured result in carbon dioxide gas which fills balloon 52 . This inflated balloon 52 assumes a position indicated in FIG. 7 . Balloon 52 is connected to base member 17 such as at 70 . It is also preferably connected to outer member 12 such as at 71 and 72 , but such connections are not necessary.
Embodiment 60 is activated by fracturing the water sachet 64 which is composed of beachable polypropylene. The water causes the sponge 62 to expand to the position shown in FIG. 9 . In this instance, the sponge 62 is connected to the sachet 64 which in turn is connected to the base member 17 . The sponge 62 is preferably an open cell compressed cellulose material.
Embodiment 78 with inflatable member 80 and expandable member 81 , function in the same manner as previously described for inflatable member 14 and expandable member 16 . When the inner sachet 84 is breached, the water mixes with the powder 88 to form a gas and fill sachet 82 or expandable member 81 . The gas escapes through pin hole 91 and fills inflatable member 80 to thereby cause the outer member 12 to erect. In order to deflate the inflatable member 80 , it is torn open along the precut or weakened portion 92 .
Embodiment 120 functions in essentially the same manner as previously described for inflatable member 14 and expandable member 16 . The difference is in the manner of activation. With inflatable member 100 positioned in outer signal member 12 as shown on FIG. 12 and inflatable member 100 and signal member 12 essentially collapsed on base member 17 , all that is required to activate embodiment 120 is to fracture sachet 102 to allow the acid solution to mix with the base materials 110 . As indicated with the previous embodiment, this mixing causes a reaction of the acid solution and the base materials to produce carbon dioxide, causing the inflatable member 100 to assume an erected position as shown in conjunction with FIG. 3 . Inflatable member 101 operates in the same manner.
The advantages of embodiment 120 over the previously described embodiments is with the sachet 102 positioned centrally near the top of the collapsed signal member 12 , it is easily located form outside the signal member 12 and fractured.
The self-erecting devices 10 , 40 , 50 , 60 and 120 have all been described with an absorbent base member 17 . If desired, this can be eliminated so the self-erecting feature is provided for a warning device as shown in FIG. 5 with embodiment 30 . In place of base member 17 , there is provided two cross members 31 and 32 which are connected at their centers such as at 72 . Outer member 12 is in turn connected at four positions 75 to the cross members 31 and 32 . The preferred material for composing cross members 31 and 32 is rigid paperboard. Although not shown in embodiment 30 , it will include the same inflatable member 14 which will be connected to the cross members 31 and 32 such as at 72 as well as inside peak 68 .
It will thus be seen that there is now provided a self-erecting device which is simple in construction as well as fast and efficient to operate. The self-erecting device provides a combined cleaning and signal apparatus which is adaptable to a wide variety of spill conditions. The absorbent layer 19 can be customized to particular facilities to accommodate the particular products being handled.
The preferred system for creating carbon dioxide gas for inflating the inflatable member 14 in embodiment 10 is water and sodium bisulfate and sodium carbonate powder. Alternatively, other systems could be employed such as the following acids: hydrochloric acid, nitric acid, sulfuric acid, citric phosphoric acid, acetic acid, lactic acid, glycolic acid, sulfamic acid, formic acid or other water soluble organic or inorganic acids, as well as sodium bisulfite, or mixtures thereof which react with one or more of the following: lithium carbonate, lithium bicarbonate, sodium sesquicarbonate sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, ammonium carbonate, ammonium bicarbonate, magnesium carbonate, calcium carbonate or other bicarbonates or carbonates, or mixtures thereof.
Certain preferred plastic materials for fabricating the outer member 12 , inflatable member 14 , sachets 20 , 22 , 54 , 55 , 64 and pad 34 have been previously indicated. However, other materials could be employed such as the outer member 12 could be low-density polyethylene, polypropylene, polyamide, woven or nonwoven cotton or synthetic fabric, paper, foil, or other materials capable of being formed into flexible sheets. The inflatable members 14 , 80 , 100 and 101 could be low-density polyethylene, high-density polyethylene, vinyl, nylon (polyamide), natural or synthetic rubber or other materials capable of being formed into a flexible, sealable tube which can then hold pressure upon inflation. The breakable sachets 20 , 22 , 54 , 55 , 64 and pad 34 could be low-density polyethylene, high-density polyethylene, vinyl, nylon (polyamide), and foil or foil laminates thereof or other materials capable of holding liquids with minimal permeation through the film. Sachets 82 , 84 , 102 and 103 could also be composed of the previously indicated materials other than polyethylene or the polyethylene terephthalate/polyethylene laminate. A certain preferred nonwoven fabric has been previously indicated for covering 18 . Other fabrics such as a nonwoven fabric comprised of cellulose and/or polypropylene or polyethylene, heavyweight paper, or polymer reinforced paper can be used. In the instance of covering 18 a , other materials such as a nonwoven or woven fabric or a liquid impervious layer such as aluminum foil, sheet polyethylene or propylene, could be employed. While a preferred material has been indicated for absorbent layer 19 , other materials could be employed such as polypropylene or polyethylene fibers, cellulosic fibers, wood flour, sawdust, ground dried corncob, diatomaceous earth, ground pumice, dried clay, cat litter, vermiculite, synthetic clay, fumed silica, fuller's earth, or similar functional materials. Cross members 31 and 32 are composed of rigid paperboard. However, other materials could be employed such as wood, metal, corrugated paperboard, or any moldable plastic or plastic composites with sufficient thickness and strength to form a semi-rigid base. While certain preferred stain removers having been previously indicated for certain stains, others can be used such as combinations of detergents, builders, chelating agents, or solvents.
The unique self-erecting device has been described for use with spills. If desired, it can be employed in conjunction with any slippery condition such as wet mopped floors to signal a slippery condition.
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A self-erecting device which can serve as a signaling unit. An absorbent pad connected to a self-erecting device results in a combined signal and spill absorbing unit. The self-erecting and absorbing device is simple in construction and easy to operate. In an alternative embodiment, the self-erecting device can include a carpet cleaner in the absorbent pad.
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The present invention relates to a modular personal security system.
BACKGROUND OF THE INVENTION
There are a wide variety of devices on the market which are used for personal security. A partial list includes, a strobe light flash, a chemical spray, an alarm, and a high voltage stun device. The number of possible devices expands every year as new technologies develop.
The needs of the individuals who use personal security devices vary tremendously. A police officer may need a potent, but nonlethal, alternative to a handgun. A teen or senior citizen may need a device which will provide defense to an attack on their person. A security guard may need a combination of these security features. When personal preferences are also factored in, it is apparent that there is no one security device suitable for all needs.
The concept of a modular personal security device is known; having been disclosed in U.S. Pat. No. 4,716,402 granted to Francis in 1987. The Francis reference is primarily a room security device that is capable of playing a secondary personal security role. The problem with the Francis reference is that the components have minimal coordination and, as such, the device is more of an aggregation of features than a coordinated personal security device.
SUMMARY OF THE INVENTION
What is required is a modular personal security system with an option to activate a plurality of coordinated defensive modules in a sequence, or simultaneously.
According to the present invention there is provided a modular personal security device which includes a body having an interior battery receiving cavity, a handgrip and at least one module mounting surface whereby electronic and mechanical modules are mounted to the body. A first power supply circuit connects the battery receiving cavity with a first power switch connector on the body and a first power connector on the module mounting surface. A second power supply circuit connects the battery receiving cavity with a second switch connector on the body and a second power connector on the module mounting surface. The first power supply circuit and the second power supply circuit have at least one ground line extending from the battery receiving cavity to a first ground connector and a second ground connector on the module mounting surface. A multi-position trigger activated switch module is connected to the first power switch connector and the second power switch connector. Upon the trigger being manually pressed to one position the first power switch connector completes the first power supply circuit thereby supplying power to a modular unit mated with the first power connector. Upon the trigger being further pressed to another position the second power switch connector completes the second power supply circuit thereby supplying power to a modular unit mated with the second power connector. Upon the trigger being further pressed to subsequent positions the first power switch connector completes the first power supply circuit and the second power switch connector completes the second power supply circuit thereby simultaneously supplying power to a modular unit mated with the first power connector and a modular unit mated with the second power connector.
With the personal security device, as described, the multi-position trigger switch activates modules when the trigger is pressed.
Although beneficial results may be obtained through the use of a personal security device, as described above, the use of disabling sprays is very common in personal security devices. There is a need to coordinate the use of disabling sprays with electronic and mechanical components. Even more beneficial results may, therefore, be obtained when the body has a spray tank mount and a liquid conduit extending through the body. The liquid conduit must have a connector end positioned adjacent the spray tank mount and a nozzle end. The spray tank used has male adaptor insertable into the connector end of the liquid conduit. The spray tank has an actuating valve which is on a common plane with the trigger, such that the trigger engages the actuating valve as the trigger is depressed. When the personal security device has provision for the addition of the spray tank module, as described above, by continuing to press the trigger the actuating valve on the spray tank module is depressed to release the disabling spray at end of trigger travel. This feature allows for a complete systematic activation for modular units connected to the first power supply circuit, modular units connected to the second power supply circuit and modular spray systems. The activation can be made sequentially or simultaneously depending upon trigger positioning and the speed of trigger movement.
Although beneficial results may be obtained through the use of the personal security device, as described above, it would be disastrous if the electronic and mechanical modules became detached from the body during an attack by an assailant. Even more beneficial results may, therefore, be obtained when means is provided for locking the electronic and mechanical modules to the body. The preferred means includes modules having mating members in the form of rotatably mounted depending key-like fasteners that axially align with key hole receptacles located on the body of the device or other modules designed for stacking. The key-like fasteners are inserted into the key hole and partially rotated to lock members in a mated position.
Most airports have strict regulations regarding taking pressurized containers onto aircraft. There are also strict regulations as to what spray medium is legal in various jurisdictions. Even more beneficial results may, therefore, be obtained when the spray tank module has a standard air valve whereby the contents of the spray tank may be replenished with a spray medium which is legal for the jurisdiction and then pressurized with an air pump. This enables the pressure to be released from the tank prior to boarding an aircraft, and upon landing the tank can be recharged at any service station or wherever there is access to an air compressor. It also enables the spray medium drained, if that is desired.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features of the invention will become more apparent from the following description in which reference is made to the appended drawings, wherein:
FIG. 1 is an exploded perspective view of switch modules and a body for a modular personal security device constructed in accordance with the teachings of the present invention with conductive circuits superimposed thereon.
FIG. 2 is an exploded side elevation view of modular electronic units and the body illustrated in FIG. 1 with switch modules attached.
FIG. 3 is a side elevation view of a fully assembled modular security device illustrated in FIG. 2.
FIG. 4 is a partially cut away side elevation view of a spray tank module.
FIG. 5 is an exploded end elevation view of the body illustrated in FIG. 1 and the spray tank module illustrated in FIG. 4.
FIG. 6 is a side elevation view of the body illustrated in FIG. 1 interconnected with the spray tank module illustrated in FIG. 4.
FIG. 7 is a detailed side elevation view of a trigger mechanism illustrated in FIG. 1.
FIG. 8 is a detailed side elevation view of a rotary switch illustrated in FIG. 7.
FIG. 9 is a section view of the rotary switch illustrated in FIG. 8.
FIG. 10 is a side elevation view in longitudinal section of a actuating valve illustrated in FIG. 4.
FIG. 11 is a side elevation view in longitudinal section of a actuating valve illustrated in FIG. 4.
FIG. 12 is an exploded detailed view of a locking mechanism.
FIG. 13 is an exploded side elevation view of a personal security device constructed in accordance with the teachings of the present invention.
FIG. 14 is an assembled side elevation view of the personal security device illustrated in FIG. 13.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred embodiment, a modular personal security device generally identified by reference numeral 10, will now be described with reference to FIGS. 1 through 14.
Referring to FIG. 1, the modular personal security device 10 includes a body 12 having an interior battery receiving cavity 14, a handgrip 16 and a top mounting surface 18 for electronic and mechanical modules (not shown). Mounting points 66a and 30a are provided for electronic switch modules 66 and 30, respectively, on body 12. Battery receiving cavity 14 has a 3 volt power source consisting of two 1.5 volt `AA` batteries 20 connected in series. There is also a 9 volt battery 22, which provides additional power for a high voltage power source as will be hereinafter further explained. Personal security device 10 operates with modular units which will hereinafter be more fully described; not all of which require the same power. Batteries 20 constitutes a low voltage power source. The voltage of 1.5 volt batteries 20 combined in series with 9 volt battery 22 provide a high voltage power source of 12 volts. A first power supply circuit 24 extends from the low voltage power source represented by batteries 20 within battery receiving cavity 14 to female switch connectors 24a, 24b and 24c. Slide switch bank module 30 and rotary trigger switch module 66 have male conductive connectors 62 which mate with female connectors 24a, 24b, and 24c. Some of male conductive connectors 62 extend to power lines 24f and 24d to supply power lines 24f and 24d when the switches are activated. Referring to FIGS. 1 and 12, the switch members have rotatably mounted depending key-like fasteners 60, that insert into axially aligned key hole receptacles 58b to attach rotary trigger switch module 66 onto body 12 at mounting point 66a and key hole receptacles 58c to attach slide switch bank module 30 onto body 12 at mounting point 30a. The operation of switch modules 66 or 30 can complete first power supply circuit 24. First power supply circuit 24 includes a power line 24f extending to female power connector 24g located on mounting surface 18 and a power line 24d extending to a female power connector 24e also located on mounting surface 18. Female power connector 24g is intended to receive a low beam light and female power connector 24e is intended to receive a high beam light as will hereinafter be further described. Second power supply circuit 26 extends from the high voltage power source represented by the combined power of batteries 20 and 22 within battery receiving cavity 14 to female connectors 26a and 26b. As previously described, slide switch bank 30 and rotary trigger switch 66 have male conductive connectors 62 that are insertable into female connectors 26a and 26b to supply power into switch modules with some of male conductive connectors 62 used to extend power to lines 26c and 26d when switches are activated. The operation of switch modules 66 or 30 can complete second power supply circuit 26. Second power supply circuit 26 includes power lines 26c and 26d to female power connector 26e located on top mounting surface 18. Female power connector 26e is mated with modular units requiring high voltage. Both high and low voltage circuits share a common ground source extending from low voltage battery 20, along ground line 28 to female ground connector 28b for high voltage circuit, and female ground connector 28a for the low voltage circuit. Referring to FIG. 12 all modules have a rotatably mounted depending key-like fastener 60 that inserts into key hole receptacles 58 located on body 12 or on companion modules designed for stacking. Once inserted key-like fastener 60 is rotated 1/4 turn with a screwdriver or the like to move a projection 60L on key-like fastener 60 out of register with key hole receptacle 58 to place key-like fastener 60 in a locked position. Compression or lock washer 60a maintains key-like fastener 60 in the locked position.
Referring to FIG. 2 and 3, there is illustrated body 12 with slide switch bank module 30, rotary trigger switch module 66, a low voltage high-beam/low beam light module 46 with a plurality of high voltage modular electronic units; high voltage stun module 109, and pain field generator 110. Electronic modules 109, 46 and 110 all have depending male members 50 that play a role in permitting the modules to interlock with body 12 or with other modules in a stacked fashion. Male members 50 each have rotatably mounted depending key-like fasteners 60. Male members 50 are positioned to overlap until key-like fasteners 60 are axially aligned with key holes 58 on body 12 (or 58d on module 109). Key-like fasteners 60 are then inserted into key holes 58 or 58d and rotated 1/4 turn to lock them together. In FIGS. 2 and 3, light module 46 and high voltage stun module 109 are secured in this fashion to body 12, and pain field generator 110 is secured in this fashion to high voltage stun module 109. Modular electronic units 109, 46 and 110 also have depending male conductive connectors 62. When modular electronic unit 46 is positioned on top mounting surface 18, male conductive connectors 62 mate with first power connectors 24g, 24e and ground connect 28a. When module 109 is positioned on top mounting surface 18, the modules male conductive connectors 62 mate with second power connector 26e and ground connect 28b. High voltage stun module 109 also has female conductive connectors 64. Female conductive connectors 64 mate with male conductive connectors 62 of pain field generator 110 to enable high voltage stun module 109 to serve as a conduit for electrical conduction from second power connector 26e and ground connect 28b on top mounting surface 18 to energize pain field generator 110.
Referring to FIGS. 2 and 3, positioned on body 12 is a slide switch bank module 30 to allow continuous operation of selected electronic modules independently from multi-position rotary trigger switch 66. Rotary trigger switch 66 allows a momentary operation of the electronic modules. Referring to FIG. 9, rotary switch 66 has a rotatable contact member 68. Referring to FIGS. 7 and 8, contact member 68 is non-rotatably coupled with pinion gear 70. Referring to FIG. 7 and 9, upon trigger 72 being manually pressed, the engagement between rack 74 and pinion gear 70 moves rotatable contact member 68 of rotary switch 66 in a counterclockwise direction to a first position, connecting first power supply circuit 24 with low beam light power line 24f. Upon trigger 72 being further pressed, the rotatable contact member 68 of rotary switch 66 assumes a second position connecting first power supply circuit 24 with high beam light power line 24d. With continued trigger travel, the third and fourth rotary switch positions utilize the two pole capability of rotary switch 66, by activating the low voltage, high beam lights power line 24d, in parallel with the high voltage modules power line 26d simultaneously, with contact member 68 shown in this third rotary switch position in FIG. 9. Trigger 72 is blocked on fourth switch position, in order to prevent rotatable contact member 68 to continue into an unwanted position. When finger pressure is released from trigger 72, compression spring 77 returns trigger 72 causing rotatable contact member 68 to move in a clockwise direction to a "rest" or "off" fifth rotary switch position, where trigger 72 is blocked, to prevent compression spring 77 from extending rotatable contact member 68 past "rest" position into an activated switch position. Referring to FIG. 9 the diagram illustrates rotatable contact member 68 in a third rotary switch position activating low voltage power to high beam lights power line 24d in parallel with high voltage power extended to high voltage modules power line 26d simultaneously, 68a represents a nonconductive member interposed between the first and second power circuits, with low voltage power supply circuit 24 extending power via rotatable contact member 68 to low voltage contacts (24d, 24f) above line in diagram depicting nonconductive member 68a in parallel simultaneously with high voltage power supply circuit 26 extending high voltage power via rotatable contact member 68 to high voltage contacts (26d) below line in diagram depicting nonconductive member 68a. 24z and 26z represent the "rest" or "off" fifth rotary switch position rotatable contact member 68 rests in when not activated by trigger 72. Power lines from supply circuits 24 and 26 are not connected to contacts 24z and 26z in the fifth rotary switch position produces an off position.
The module configuration illustrated in FIGS. 2 and 3, gives the capability to activate this module combination in sequence by rotary trigger switch 66. By pressing trigger 72 to a first switch position, low beam portion of light module 46 is activated. Pressing trigger to a second switch position deactivates the low beam portion of light module 46 and turns on the high beam portion. Third and fourth rotary switch positions activate high beam light 46, stun module 109 and pain field generator 110 in unison, with high beam light 46 being able to illuminate a potential adversary, and pain field generator 110 designed to produce a high frequency sound oscillation that when directed towards an assailant can cause disorientation, ear discomfort, etc., as well as draw attention to potential assistance due to its siren effect. If the effects of pain field generator 110 do not deter a physical confrontation with the assailant, the activated stun module 109 can be used to neutralize attack by making physical contact with assailant with stun modules high voltage electrode 109a inflicting a low amperage, nonlethal electrical shock. Pressing trigger 72 at a fast rate into third or fourth switch positions, all modules will instantly activate simultaneously. Slide switches 36 and 30 can be operated independently or in unison with rotary trigger switch 66 to produce different combinations of module activations.
Referring to FIG. 1, body 12 has a spray tank mount in the form of a dovetail groove 76 on handgrip 16. Referring to FIG. 6, a liquid conduit 78 extends through body 12. Liquid conduit 78 has a connector end 80 positioned adjacent dovetail groove 76 and an opposed end 82 with a forwardly directed nozzle 84. Referring to FIG. 5, a spray tank 86 having a dovetail tongue 88 mates with dovetail groove 76 to connect spray tank 86 to body 12. Spray tank 86 has a male outlet adaptor 90 insertable into connector end 80 of liquid conduit 78. Male adaptor 90 has rubber seal 90a attached to prevent leakage at connection point with connector end 80. Spray tank 86 has a rotatably mounted key-like fastener 60, that is then inserted into receptacle 58a located adjacent connector end 80 and rotated 1/4 turn to lock spray tank 86 to body 12. Spray tank 86 has an actuating valve 92. FIGS. 10 and 11, provide detailed views of actuating valve 92; an improvement over a standard air valve which produces a push button fluid control and includes a dip tube inlet 95, a male outlet adaptor 90, a plunger member 94, a valve cap 94a, and a sealing membrane 102. Actuating valve 92 consists of a cylindrical barrel 93 with fluid communication through dip tube inlet 95 and male outlet adaptor 90. A valve member 98 rests against a valve seat 100 in between dip tube inlet 95 and male outlet adaptor 90 to control the flow of fluids from dip tube inlet 95 to male outlet adaptor 90. Valve member 98 is attached to a moveable member 96. Referring to FIG. 11, a plunger member 94 acts upon movable member 96 to move valve member 98 away from valve seat 100 to selectively allow a flow of fluids. Plunger member 94 is positioned in a bored-out stemmed valve cap 94a. A flexible sealing membrane 102 is interposed between plunger member 94 and moveable member 96. Referring to FIG. 14, actuating valve 92 is on a common plane with trigger 72. Trigger 72 engages plunger member 94 of actuating valve 92 when trigger 72 is fully depressed to the end of travel.
Referring to FIG. 4 and 6, spray tank 86 has an air valve 104 that enables spray tank 86 to be pressurized by means of an air pump (not shown), with pressure monitored by gauge 86a, and pressure relief valve 86b. Air valve 104 can also be used to recharge tank reservoir by injecting liquid through air valve 104 with a syringe type device, equipped with an air valve adaptor. There are a variety of modular units than can be employed. FIG. 2 and 3 show a high and low beam light module 46 with a combined high voltage stun module 109 and pain field generator 110. As described in relation to modular electronics 109, 46, and 110, all modular units have depending male conductive connectors 62 and depending male members 50 with rotatably mounted depending key-like fasteners 60. Referring to FIGS. 2 and 3, some modules, such as modules 109, are intended to have other modules stacked on top of them and therefore have key-hole receptacles 58d and female conductive connectors 64.
FIG. 6 illustrates weather-resistant plate 181 on top mounting surface 18 if high voltage modules are deleted. Plates 301, 661 and 461 are used if switch and light modules are not required, for example if only the spray system was desired, which could be discharged by finger pressure. If stacking modules with top female electrical connectors 64 are used, plate 181 can be attached on top of the last module in the stack to insure electronic circuits are shielded from the weather.
Referring to FIGS. 13 and 14, there is illustrated a version of personal security device 10 with modules that can be activated in sequence or simultaneously. The modules provided include high beam/low beam light 46a (smaller version of module 46) pain field generator 110, rotary trigger switch 66, slide switch bank 30 and spray tank 86.
The use and operation of modular personal security device 10 will now be described with reference to FIGS. 1 through 14. In order to prepare the version of personal security device 10 illustrated in FIG. 14 for use, spray tank 86 is attached to body 12 by mating dovetail tongue 88 with dovetail groove 76 and inserting male outlet adaptor 90 into connector end 80 of liquid conduit 78, as illustrated in FIGS. 5 and 6. Spray tank module 86 has a rotatably mounted key-like fastener 60. Key-like fastener 60 is axially aligned with and then inserted into key hole receptacle 58a on body 12. By rotating key-like fastener 60 1/4 turn spray tank module 86 is locked to body 12 with male outlet adaptor 90 projecting into connector end 80 of liquid conduit 78. Referring to FIGS. 13 and 14, painfield generator module 110 is then attached to top mounting surface 18 of body 12 by overlapping male members 50 of module 110 and inserting key-like fasteners 60 into key hole receptacles 58 on body 12. By rotating key-like fasteners 60 pain field generator module 110 is locked to body 12. Male conductive connectors 62 on pain field generator module 110 mate with high voltage female power connector 26e and female ground connect 28b. Light module 46a is attached to top mounting surface 18 in a similar fashion where male connectors 62 mate with low voltage female power connectors 24g, 24e and ground connect 28a. Rotary switch module 66 is similarly attached by mating key-like fasteners 60 with key hole receptacles 58b on body 12 at mounting point 66a. Slide switch module 30 also attaches in a similar fashion by mating key-like fasteners 60 with key hole receptacles 58c on body 12 at mounting point 30a. When switch modules 30 and 66 are attached male conductive connectors 62 on the switch modules mate with female switch connectors at mounting points 30a and 66a, respectively, to connect with the switch circuits illustrated in FIG. 1. Once this module combination is attached to body 12, the sequence of activation would be in accordance with the following description. The person pulls trigger 72 at a moderate speed on rotary switch 66 to the first power switch position in order to place light 46a on low beam, for example low beam light may be used to shine light upon a car door, house door or the like to enable safe entry with key. The person pulls trigger 72 to the second rotary switch position which deactivates low beam light and turns on high beam light portion of 46a if a more intense light is needed. If the operator feels threatened in any way, by pressing trigger to third rotary switch position, high beam light 46a and pain field generator 110 are activated in unison with the pain field generator being an alarm designed to produce a high frequency sound oscillation that when directed towards an assailant, disorientation, ear discomfort, etc. can develop within the assailant, as well as drawing attention to potential assistance within the area due to the siren sound effect of module 110. If a hitch-pin (not shown) is used to restrain plunger member 94 on actuating valve 92 located on spray tank 86, trigger 72 becomes restrained against hitch-pin, allowing for a continuous third rotary switch positions activation of high beam light and pain field generator, and also prevents premature or accidental spray discharges. If threat situation increases, the hitch pin can be removed to allow trigger 72 to be pressed to the end of travel activating fourth rotary switch position of pain field generator 110, high beam light 46a, simultaneously with plunger member 94 of actuating valve 92 being depressed to direct a disabling spray from spray tank 86 out of nozzle 84 at the attacker, with high beam light 46a having the capability to illuminate intended target for the spray direction if needed, in parallel with the activated pain field generators high frequency sound oscillation effects on assailant as well as potential to draw attention for possible assistance from the siren sound effect of module 110. By pressing rotary trigger 72 at a fast rate, all modules can be activated simultaneously.
It will be apparent to one skilled in the art that modifications may be made to the illustrated embodiments without departing from the spirit and scope of the invention as defined in the following claims.
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A modular personal security device is described which includes a body having an interior battery receiving cavity, a handgrip and at least one module mounting surface whereby electronic and mechanical modules are mounted to the body. A first power supply circuit connects the battery receiving cavity with a first power switch connector on the body and a first power connector on the module mounting surface. A second power supply circuit connects the battery receiving cavity with a second power switch connector on the body and a second power connector on the module mounting surface. A multi-position trigger activated switch module is connected to the first power switch connector and the second power switch connector. Upon the trigger being pressed to one position the first power switch connector completes the first power supply circuit. By continuing to press the trigger to another position the second power switch connector completes the second power supply circuit. Upon the trigger further being pressed to subsequent positions both the first power supply and the second power supply circuits are completed thereby simultaneously supplying power to a modular unit mated with the first power connector and a modular unit mated with the second power connector. The device, as described, is particularly suited for coordinated sequential or simultaneous use of modular units providing multiple personal security features.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to concrete control joints, and in particular, to a structurally integral hinged control joint.
2. Description of the Prior Art
Areas of poured concrete, as highway sections or airport runway sections, have been observed to experience cracking along unpredictably locatable planes. Such cracking may occur in response to tensil forces imposed at opposite ends of the slab as, for example, at the connection therewith to the next-adjacent concrete slab.
In order to limit, or at least render predictable the locations at which cracking occurs, it is common practice in the art to artificially introduce weakened areas within the concrete slab, so that cracking which would occur would be expected along the weakened planes. For example, it is known to provide across the transverse dimension of the concrete slab at predetermined locations thereon a number of cuts extending into the concrete several inches, each cut being the width of one rotary saw blade, or approximately one-eighth of an inch. The cuts are usually displaced in some predetermined pattern in the concrete slab and any cracking of the concrete maybe expected along planes emanating from the cut.
It is also a common practice in the art to introduce substantially T-shaped plastic members transversally across a slab of concrete with the upright leg of the T extending into the concrete and the arms disposed along the surface thereof. The upright leg of the T may be viewed as a weakened plane joint and concrete cracking or fracturing may be expected to occur along that weakened plane joint.
However, in the case of either prior art expedient, once the crack occured moisture is permitted to enter through the crack into the body of the concrete slab. In the case of the saw blade cut, water accumulates in the volume defined by the cut and falls by gravity into the fissures or cracks emanating therefrom. With the case of the T-shaped plastic members, moisture seeps under the extending arms of the T-shaped member along the sides of the upright leg thereof, and into the fracture extending from the lower end of the leg. The presence of moisture within the fissures within the body of the concrete erodes the concrete, and, dependent upon climatic conditions, may expand or contract in accordance with the temperature to accelerate the deterioration of the concrete body.
It would therefore be advantageous to provide a concrete control joint fabricated of a metal material in a unitized construction such that moisture and the like is prevented from entering cracks within the concrete body emanating from the control joint. It is of further advantage to provide an integrally fabricated control joint of a hinged construction such that the hinge acts as a water stop to prohibit entry of water into the fissures generated within the concrete. It would be of yet further advantage to provide a control joint having fingers or the like adaptable to engage the edges of the concrete to secure the arms of the control joint thereto to thereby protect those edges from deterioration and erosion.
SUMMARY OF THE INVENTION
This invention relates to a concrete control joint fabricated from an integral strip of metal material. The control joint is a substantially T-shaped member with the upright leg of the T being bifurcated substantially vertically therethrough to define first and second leg portions, with the lower end of the leg portions being resiliently hinged together to permit resilient movement of the bifurcated leg portions. Each bifurcated leg portion terminates in an arm of the T, the edges of the arm being folded under to define flaps which terminate in a downwardly projecting finger or lip. The fingers or lips grippingly engage the concrete in which they are disposed so that the forces of expansion and contraction generated within the concrete are transferred through the fingers and arms to the bifurcated leg portions of the T-shaped member. The hinged construction of the T-shaped member permits resilient expansion and contraction thereof so that the structural integrity of the control joint is not breached and the joint thus effectively acts as a water stop while in place. The joint may be of any predetermined axial length consistent with the environment in which it is disposed. Thus, water seepage into the cracks or fissures generated with the body of the concrete is effectively prevented by the hinged lower portions of the bifurcated upright leg of the T-shaped member along the entire axial length of the control joint. Further, the gripping engagement of the fingers with the concrete edges maintains the arms of the T-shaped member in next-adjacency to those edges to protect the same and to prevent deterioration and erosion thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be more fully understood from the following detailed description of a preferred embodiment thereof, taken in connection with the accompanying drawings which form a part of this specification, and in which:
FIG. 1 is an isolated perspective view of a concrete control joint embodying the teachings of this invention;
FIG. 2 is an end view, in elevation, of the control joint illustrated in FIG. 1;
FIG. 3 is an elevational view in vertical section through a concrete block having a control joint embodying the teachings of this invention disposed therein; and
FIGS. 4A-4E represent a sequential diagram illustrating a method of fabricating a concrete control joint embodying the teachings of this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Throughout the following description, similar reference numerals refer to similar elements in all figures of the drawings.
Referring to FIG. 1, an isolated perspective view of a concrete control joint embodying the teachings of this invention is shown. The control joint generally indicated by reference numeral 10 is fabricated of an integral sheet of metallic material such as rolled steel or the like and has a medial axis 12 therethrough. The thickness of the sheet of steel from which the joint 10 is fabricated is typically one-sixty fourth of an inch although material of any predetermined thickness may be utilized. Further, it is understood that the axial length of the control joint 10 measured along the medial axis 12 of the control joint may be any predetermined length dependent upon the environment in which the control joint utilized. For example, if the joint were utilized to control cracking within a highway section approximately 12 feet in transverse dimension, a control joint 10 embodying these teachings would be coextensive the the transverse dimension of the concrete section in which it is to be disposed. The medial axis 12 is defined as an axis containing a plane about which the control joint 10 is symmetrical.
The control joint 10 is a substantially T-shaped member which is split or bifurcated substantially entirely vertically through the upright leg 14 thereof. The slit extends through the upright leg 14 for the entire axial length of the control joint 10. The lower end 16 of the upright leg 14 of the T-shaped member is disposed so as to define a hinge arrangement whereby the first and second leg portions 14A and 14B are hingedly and resiliently connected one with the other. In the figures it is observed that the hinge 16 is defined by a substantially diamond-shaped distension although it is apparent to those skilled in the art that any suitable hinged connection between the leg portions 14A and 14B may be provided.
Connected to each leg portions 14A and 14B of the hingely bifurcated upright leg 14 are first and second arms 18A and 18B. It may be observed that the arms are bent so as to define a substantially 90° angle with respect to the leg portion with which they are associated. The arms 18 extend outwardly for a predetermined distance and are bent along an axis parallel to the medial axis to form a flap portion 20A and 20B which folds back and is disposed in next-adjacency to the undersurface 19 of the arms 18, that undersurface 19 being the surface of the arms 18 proximal to the hinge 16. From the extreme end of the flaps 20 are provided substantially vertically extending fingers, or lips, 22A and 22B. The fingers or lips 22 extend substantially perpendicularly to the flaps 20 and substantially parallel to the leg portion 14 of the hingedly bifurcated upright leg of the T-shaped member with which they are associated.
Each leg portion 14A and 14B may be provided with a hump 24. The hump portion 24 is provided adjacent the axial ends of the control joint 10 for the purpose of axial registration with the hump portions of the next-adjacent control joint so that, if desired, adjacent control joints may be connected one with the other. For this purpose, suitable connecting pins may be inserted into the openings defined between the humps of one control joint and then inserted into the opening defined between the humps of the other control joint.
With reference to FIG. 3, a control joint 10 embodying the teachings of this invention is shown disposed within a body of concrete material. The control joint 10, when inserted, defines a weakened plane joint within the body of the concrete material such that any cracks of fissures which tend to occur within the concrete (being illustrated diagrammatically at reference numeral 28) tend to be created adjacent the lower end of the upright leg 14 of the control joint 10. The control joint 10 is set into the concrete while in an unhardened state such that the fingers or lips 22 grippingly engage the concrete adjacent edge portions 30 defined therein. It may be appreciated that the edges 30 of the concrete body are overlapped and protected by the under-surfaces 19 of the arms 18 of the T-shaped control joint 10 to thus prevent erosion or deterioration thereof.
It may further be appreciated with reference to FIG. 3 that as the concrete expands and contracts in response to temperature and other environment conditions, the leg portions 14A and 14B are resiliently moveable in directions indicated by references arrows 32 from the hinged joint 16 provided at the lower ends of each of the leg portions 14A and 14B. Therefore, the structural integrity of the control joint 10 embodying the teachings of this invention is maintained throughout the expansions and contractions of the concrete in which it is disposed. Since, an effective water stop is provided by the hinged connection 16 disposed integral with the lower end of the leg portions 14A and 14B, moisture is prohibited from entering into the cracks 28 generated within the concrete body.
Referring to FIGS. 4A through 4E, a method of fabricating a concrete control joint in accordance with the teachings of this invention is diagrammatically illustrated. As discussed above, the control joint 10 embodying these teachings is fabricated from an integral sheet of metallic material. The first step in the method is to fold the integral sheet along the medial axis 12 therethrough so as to define first and second leg portions 14A and 14B (FIG. 4B) extending substantially parallel to each other. The fold along the medial axial 12 is observed to define a hinge 16 between the lower termini of the leg portion 14A and 14B. If desired, the hinged portion 16 may be suitably configured, as in a diamond or circular shape, to facilitate resilient bending of the leg portions. Further, each leg portion 14 may be bent to define a hump 24 therein, if desired. In general, however, it is necessary only that the leg portions 14 be hingedly connected at their lower ends. With reference to FIG. 4C, the next step is to bend each leg 14A and 14B along an axis parallel to and equidistant from the medial axis 12 to form arms 18A and 18B projecting outwardly from each leg portion 14A and 14B at an angle substantially 90° with respect to the leg portions 14. As viewed in FIG. 4D, this operation defines a substantially T-shaped member which is split or bifurcated substantially entirely through the upright leg thereof but still provides hinged connection between the lower ends of each portion of the leg.
With reference to FIG. 4D, each of the arms 18 is folded along an axis 36 parallel to the medial axis 12 to define the flaps 20 which extend parallel to and next-adjacent the undersurfaces 19 of the arms 18 proximal to the fold or hinge 16 which defines the leg portions 14A and 14B. Finally, each flap 20 is bent along an axis 38 parallel to the medial axis 12 to thereby define a finger, or lip, 22 extending substantially 90° with respect to the flap 20 with which it is associated.
It may be appreciated by those skilled in the art that a concrete control joint embodying the teachings of this invention provides a member suitable for controlling cracks or fissures within a concrete body in accordance with the conventional teachings in the art. Furthermore, however, the control joint embodying the teachings of this invention, through the provisiion of the bifurcated upright leg of the T-shaped member connected hingedly at the lower ends thereof, and the disposition of fingers 22 in the concrete body with which the joint 10 is associated, provides an effective water stop to prevent the entry of water into the cracks or fissures generated into the concrete body and also provides suitable protection for the edges of the concrete to prevent erosion or deterioration thereof. It is again noted that the control joint may be of any predetermined dimension dependent upon the environment in which it is disposed.
Having defined a preferred embodiment of the invention, modifications may be made thereto in view of the teachings disclosed herein by those with skill in the art. It is understood, however, that such modifications remain within the contemplation of this invention as defined in the appended claims.
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A concrete control joint is characterized by a substantially T-shaped member having a slit extending substantially vertically through the upright member of the T to define first and second leg portions thereof. The lower ends of each leg portion are resiliently and hingedly connected together. An arm of the T is connected to the end of each leg portion opposite the hinged connection. The arms terminating in fingers which extend substantially perpendicular from the underside of the arms in a direction substantially parallel to the leg portions toward the hinged joint therebetween.
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BACKGROUND OF THE INVENTION
The invention involves pneumatic tube apparatus used for drive-up and like banking in which a number of exterior customer terminals or stations, located on a driveway, for instance, are connected by pneumatic tubes to an interior teller terminal or station at the bank. Banking transactions are carried on by carriers which are pneumatically transported back and forth through the tubes between the customer and the teller stations. Sometimes a pair of tubes are utilized between each customer and teller station. Or, as in the present instance, a single tube is employed so that the carrier is either drawn or pushed through the tube depending upon in which direction it is traveling. The necessary air is supplied by a blower operating through a shift valve that determines the direction of air travel through the tube.
SUMMARY OF THE INVENTION
The main point of the present invention is to provide a simplified form of customer's station requiring a minimum amount of apparatus for handling the arrival of a carrier, making it available to the customer, and arranging for its ultimate dispatch by the customer to the teller station. To this end, the carrier arrives from the interconnecting tube directly into one end of an elongated tubular receiver horizontally mounted and slotted adjacent its remote end so that the carrier can be removed and replaced. The latter end of the receiver forms a carrier stop and also opens into a duct leading to the shift valve and the blower so that air is either exhausted from or supplied to the receiver in order respectively to receive or send a carrier. The slotted opening in the receiver in turn is closed by an enveloping sleeve slidable on the receiver. The receiver, blower, etc., are enclosed in an outer housing having a sliding door for weather and like protection. An appropriate electrical control system opens and closes the receiver sleeve and housing door, turns the blower on and off and operates the shift valve at the customer station, as well as performing similar functions at the teller station, all governed by passage of the carrier in one direction or the other and various manipulations of the carrier by the customer and the teller.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevational view of the overall system of the present invention showing the interconnected customer and teller stations.
FIG. 2 is a front isometric view of the customer station shown with the housing front and top panels removed.
FIG. 3 is an elevational view of the upper portion of the customer station, similar to FIG. 2, but with certain additional components removed and others shown in section.
FIG. 4 is a sectional view taken along the line 4--4 of FIG. 3.
FIG. 5 is an elevational view of the upper portion of the rear of the customer station with the housing back panel removed.
FIG. 6 is a side elevational view of the teller station with the housing side wall broken away.
FIG. 7 is a rear elevational view of the teller station with the housing rear wall broken away.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in FIG. 1, the system of the present invention is incorporated into an "overhead" version in which the single tube is elevated above the ground instead of being interred in it, though the latter version is of course perfectly feasible. In any event, the customer station, designated generally as CS, is connected by an appropriate pneumatic tube PT and exhaust only valve EV to the teller station, generally designated as TS. It will be understood, of course, that for each customer station CS there is a tube PT and teller station TS. The customer station CS features a rather wide, fairly low decorative housing 10 having side walls 11 and 12, and a removable cover 13 closing the top and upper portion of the front of the housing 10, the remainder of the front being closed by an additional removable panel 14. Depending upon whether the tube PT enters the side wall 11 or 12, that is, whether the station CS is a "left" or "right" hand version, the portion of the cover 13 remote from the tube entrance is rectangularly apertured at its top and front, as defined by framing 15, to provide a carrier access opening 16 and a location for a customer panel 17 to one side of the opening 16.
An inner floor 20 of the housing 10 mounts the blower and motor 21 and the solenoid operated shift valve 22, circuit connected at T1, together with a cabinet 23 for various electrical conponents (see FIG. 2). A forward shelf 24 and inner backwall 25 within the housing 10 above the level of the panel 14 support an upright receiver end block 26 inboard from and parallel to the sidewall 12 (see FIGS. 3 and 4). To the inboard face of the block 26 is screwed one end of an annular fitting 27 in which is seated an annular carrier stop cushion 28 of elastomeric material. The belled end of a hose coupling 29 opens out into the fitting 27 through the cushion 28 and block 26, its other end being connected to a hose 30 passing through the rear wall 25 and attached in turn to one port of the shift valve 22. Into the other end of the fitting 27 is spigotted the remote end of a horizontal tubular carrier receiver 31, of Teflon-impregnated annodized aluminum, whose other end is seated in a fitting 32 bolted together with an adapter 33 to and through the opposite end wall 11. The pneumatic tube PT is connected in turn to the adapter 33. Adjacent the fitting 27 the upper half or so of the receiver 31 is apertured or slotted to provide an elongated carrier receptacle 34. The latter is opened and closed by an eveloping annodized aluminum sleeve 35, also Teflon-impregnated, slidable on the receiver 31 and which when closed seats within a counterbore in the fitting 27.
The sleeve 35 is operated by an appropriate reversible electric motor and gearbox 40 (see FIGS. 4 and 5) supported from a bracket 41 below the shelf 24 which drive a pulley 42 through a slip clutch 43, the pulley 42 being appropriately journaled on brackets 44 (see FIG. 3) from the shelf 24 directly beneath the sleeve 35. A laterally opposite pulley 45 is similarly journaled on brackets 46 and a belt 47 passes over both, being attached at 48 to the sleeve 35. For the latter purpose the shelf 24 is apertured to allow the pulleys 42 and 45 and the upper flight of the belt 47 to pass thereabove. Sleeve open and close limit switches SW1 and SW2 (see FIG. 3) are disposed above the sleeve 35 on suitable brackets, while a carrier arrive-send plunger switch SW3 of the momentary contact type is disposed at the lower outboard face of the end block 26 with its plunger upright. Upon the latter rests the outer end of a switch operating lever 49 extending through the fitting 27 and along the floor of the receiver 31 below the carrier receptacle 34, its inner end being offset and loosely captured in a slot 50 in the floor of the receiver.
The carrier access opening 16 in the housing 10 is provided with a horizontally sliding closure or door 55 bent from suitable sheet metal. The door 55 is carried by a pair of linear ball slides 56 mounted to the bottom and rear edges of the door 55 and to front and top inner brace panels 57 and 58 extending between the side panels 11 and 12. A T-shaped protective member 59 overlies the lower slide 56 and the space between the carrier access opening 16 and the sleeve 35. The door 55 is propelled between open and closed positions by a rack 60 attached along the rear edge of the door 55 and a pinion 61 driven by a reversible motor and gearbox 62 through a slip clutch 63, the motor and gearbox 62 being mounted to a bracket 64 depending from the panel 58 (see FIGS. 2, 4 and 5). Provision for locking the door 55 closed is made by a vertical latch 65, engageable with an aperture in the door 55, slidable in a bracket 66 attached to the inner back wall 25 and driven by a solenoid T2 similarly mounted. A pair of open and closed door limit switches SW4 and SW5 are fixed on the panel 58 in the route of the door 55, and upon the customer panel 17 is mounted a microphone 67, a teller call switch SW6 and a carrier send switch SW7, a speaker 68 being mounted on the backwall 25 behind the receiver 31 (see FIGS. 1 and 5).
The corresponding teller station TS, on the other hand, comprises a much smaller, upright rectangular housing 80 including sidewalls 81, a rear wall 82, top wall 83, bottom wall 84, a lower fixed front wall 85, and an upper control panel 86. Forwardly mounted within the housing 80 is an upright aluminum casting or receiver 90 fixed to and between a pair of upright plates 91 attached to the housing 80. The receiver 90 has a cylindrical bore to receive a carrier through its upper end into which is seated an inner adapter 92 extending through the top wall 83 and an outer adapter 92b for connection to the tube PT. The front of the receiver 90 between the wall 85 and panel 86 is open to provide a carrier receptacle 93 whose mouth 93a is reversely inclined and generally rectangular in shape, being fitted with sealing material 94. Against the latter bear the edges of a complementary shaped door 95, hinged at 96 at its lower end to the receiver 90, which opens outwardly as indicated for access to the latter. The bottom of the door 95 is fitted with a U-shaped carrier stop cushion 97 up through which extends the plunger of a switch SW8 of the momentary contact type. To a boss 98 on the rear of the receiver 90 partially below the cushion 97 is fitted an intake only valve IV which communicates through an adapter 99 in the bottom wall 84 with the exterior of the housing 80.
The door 95 is opened and closed by a pair of link arms 100 hinged at 101 at their outer ends to the sides of the door 95, their inner ends being hinged at 102 to the outer ends of a pair of pitman arms 103. The other ends of the latter are fixed to the ends of a transverse shaft 104 journaled between a pair of spaced upright mounting plates 105 extending rearwardly from and attached to the receiver 90 between the plates 91. Fixed to the midpoint of the shaft 104 is a bushing 106 connected through a slip clutch 107 to a pulley 108 rotable on the shaft 104. A drive belt 109 extends from the pulley 108 up over a drive pulley 110 driven by a reversible motor and gearbox 111 mounted by brackets 112 to the plates 105. A pair of door open and closed limit switches SW9 and SW10 are mounted to one of the plates 105 and operated by a cam 113 fixed to the shaft 104 opposite the bushing 106. On the control panel 86 are mounted a carrier send-recall switch SW11, a receptacle open-close switch SW12, a teller door open-close switch SW13 and a power off-on switch SW14, plus carrier-present and door-receptacle open indicator lamps L1 and L2 for the customer station CS.
The electrical control circuitry for the two stations CS and TS can be of any conventional nature as will be readily apparent and, since it plays no part in the present invention, need not be described other than functionally. An example of similar circuitry is found in U.S. Pat. No. 3,841,584, for instance. Suffice to say that to place the system in operation the power switch SW14 is thrown to ready the various electrical components, the switch SW14 also opening the door 55 at the customer station CS. The door 55 is under the sole control of the teller who can open it in the morning and close it in the evening or upon each transaction by a customer in the event of rain, for instance. Or, of course, the door 55 could be arranged to open and close automatically upon each transaction. In any event, the door motor 62 is activated, whereupon the pinion 61 and rack 60 cause the door 55 to slide to one side until halted by the limit switch SW4 to expose the sleeve 35 closing the carrier receptacle 34. If a carrier is not already in the latter, whose presence will be shown by the lamp L1, the teller can open his door 95 by the switch SW13 which activates the motor 111 and which through the pulleys 108 and 110 and the belt 109 rotates the shaft 104. The pitman arms 103 thereupon move to push the link arms 100 and the door 95 about its pivot 96 to the position shown in broken lines in FIG. 6, whereupon the cam 113 and the limit switch SW9 shut off the motor 111. When a carrier is placed on the cushion 97, the plunger switch SW8 is depressed, activating the motor 111 in the opposite direction to close the door 95 until halted by the limit switch SW10, whereupon the carrier is fully within the receptacle 93. The switches SW8 and SW10 together then activate the blower 21 at the station CS and the valve 22 to shift the latter from its neutral position to that causing the blower 21 to draw air from the hose 30. The depression thus created in the receiver 31 through the port 29, the tube PT and receiver 90 draws air in through the intake valve IV beneath the carrier on the door 95 and thereby propels it through the tube PT. As the carrier arrives in the receptacle 34, it depresses the lever 49, throwing the switch SW3, and halts against the cushion 28. The switch SW3 also thereupon returns the shift valve 22 to its neutral position and turns off the blower 21. The sleeve motor 40 is likewise activated by the switch SW3 at the same time and through the pulleys 42 and 45 and the belt 47 slides the sleeve 35 to one side to expose the carrier receptacle 34 and the carrier therein, the motor 40 being halted by the limit switch SW1. The depression of switch SW3 also lights the lamp L1 to indicate to the teller the presence of the carrier at the customer station CS.
When the customer removes the carrier, the lever 49 releases the switch SW3 and indicates at L1 that the carrier has been removed and at L2 that the receiver 34 is open. Replacement of the carrier in the receptacle 34 again depresses the lever 49 and switch SW3 and sets the circuit for return of the carrier. Then the customer pushes the carrier send switch SW7, whereupon the sleeve motor 40 is activated to close the receptacle 34 until halted by the limit switch SW2. The latter switch then also turns on the blower 21 and moves the shift valve 22 to its opposite position to supply air under pressure through the hose 30 and port 29 against the carrier, sending the latter from the receiver 31 through the tube PT. The air ahead of the carrier is exhausted through the valve EV, and once past the latter the pressurized air also is exhausted from the tube PT through the valve EV. The carrier continues under its own momentum down into the receiver 90 and receptacle 93 at the teller station, being braked by the dead air in the receiver 90, striking the cushion 97 and depressing the plunger switch SW8. The latter switch then returns the shift valve 22 to neutral, shuts off the blower 21 and opens the door 95 in the manner previously described to present the carrier to the teller. As long as the carrier remains on the door 95 the latter stays open. If, however, the carrier is removed and then replaced on the door 95 within a period of a few seconds, that is to say, if the teller should "fumble" the carrier, a delay circuit prevents the door 95 closing and the sending of the carrier. After that period the circuit is automatically set for return of the carrier, and when the teller has completed his transaction and replaced the carrier on the door 95, the plunger switch SW8 then closes the door 95 and sends the carrier in the manner previously related. Any time a carrier is not being sent through the system the teller can open and close the door 95 with the switch SW12 regardless of the presence of the carrier on the door 95. Should the teller make an error, for example, sending the wrong carrier or some other error, he can recall the carrier, whether in the tube PT or the receptacle 34, by pressing the carrier recall switch SW11 which will appropriately reverse or activate, as the case may be, the blower 21 and shift valve 22. In short, the teller can override the logic and control at the customer station CS at any time. If a customer should need help, he can push the call switch SW6 and converse with the teller over the microphone 67 and the speaker 68.
Essentially, therefore, especially when compared with other apparatus for the same purpose, the present invention provides a single pneumatic tube system and customer station which is markedly simplier and thus lower in cost and upkeep. The movements required by a customer at the customer station are natural ones; he simply reaches down and into the receptacle 34, whether returning or removing the carrier, so that the latter can always remain in a natural and comfortable horizontal position. Preferably, the exhaust valve EV, and the intake valve IV through the adapter 99, are ducted to the out-of-doors, rather than the interior of the teller's station, so that on cold days especially, no warm air is passed through the tube PT to cause condensation therein under those conditions. The latter arrangement also prevents cold air and auto exhaust fumes from being dumped into the enclosed teller station. In any event, though the present invention has been described in terms of a particular embodiment, being the best mode known of carrying out the invention, it is not limited to the embodiment alone. Instead the following claims are to be read as encompassing all adaptations and modifications of the invention falling within its spirit and scope.
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The customer station or terminal of a pneumatic carrier system for drive-up banking and the like employing a single interconnecting tube features a horizontally disposed, tubular carrier receiver connected at one end to the tube and slotted adjacent its other end for insertion and removal of a carrier. The slotted aperture is opened and closed by a sliding sleeve controlled by the arrival of a carrier at and its subsequent replacement in the receiver by a customer.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a divisional of commonly owned, copending application Ser. No. 13/313,085 filed Dec. 7, 2011, now U.S. Pat. No. 8,680,345. Application Ser. No. 13/313,085 claims domestic priority from commonly owned, U.S. Provisional Patent Application Ser. No. 61/430,630, filed Jan. 7, 2011. The disclosures of these applications are incorporated herein by reference.
FIELD OF THE INVENTION
This invention relates to methods and systems for producing hydrochloro-fluoroolefins, particularly 2-chloro-3,3,3-trifluoropropene (also known as HCFO-1233xf, or 1233xf) which is useful as intermediate in the production of 2,3,3,3-tetrafluoropropene (also known as HFO-1234yf or 1234yf). 1233xf can also be used as a monomer in production of chlorofluoropolymers.
BACKGROUND OF THE INVENTION
Processes for synthesizing 1233xf are known. For example, U.S. Pat. No. 7,795,480 discloses a process for preparing 1233xf via the gas-phase reaction of 1,1,2,3-tetrachloropropene, 2,3,3,3-tetrachloropropene, or 1,1,1,2,3-pentachloro-propane with hydrogen fluoride (HF) in the presence of a catalyst and a stabilizer. However, this process suffers from catalyst deactivation resulting in a low yields and a need for catalyst regeneration.
Other processes for the production of 1233xf exist. See for example, U.S. Patent Application Ser. No. 61/202,966, which discloses a method of 1233xf production via vapor phase non-catalytic fluorination of tetrachloropropene or pentachloropropane at high temperatures exceeding 300° C. This method suffers from low yields due to instability of starting materials at high temperature in the presence of HF which facilitates undesired side reactions resulting in undesired by-product formation.
The high operating temperatures and undesired by-product formation disclosed in the above referenced documents result in high operating and production costs. Accordingly, there remains a need for a process for producing 1233xf in high yields. This invention satisfies that need.
SUMMARY OF THE INVENTION
The current invention solves these problems by producing 1233xf via the continuous low temperature liquid phase reaction of 1,1,1,2,3-pentachloropropane (also known as HCC-240db or 240db) with anhydrous HF, without use of a catalyst. However, without the use of a catalyst, the problem of slower reaction rates is introduced. The present inventors have solved this problem by the use of a series of reaction vessels, each one in succession converting a portion of the original reactants fed to the lead reactor and run in a continuous fashion. The number of reactors in a particular train is determined by their size (bigger means more capital money is required, but fewer would be required) and the desired production rate of 1233xf. At least one reactor can be used. Preferably, at least two reactors can be used. More preferably, at least three reactors can be used. Most preferably, more than three reactors can be used.
As an example, the lead reactor converts 70% of the 240db feed, of which only 50% is converted to the desired product, while the rest is only partially fluorinated to produce intermediates including compounds such as 1,1,2,3-tetrachloro-1-fluoropropane (HCFC-241db or 241db), 1,2,3-trichloro-1,1-difluoropropane (HCFC-242db or 242db), and 2,3-dichloro-1,1,1-trifluoro-propane (HCFC-243db or 243db), 2,3,3-trichloro-3-fluoropropene (HCFO-1231xf), 2,3-dichloro-3,3-difluoropropene (HCFO-1232xf) among others. The unconverted 240db and under-fluorinated intermediates are high boiling compounds relative to 1233xf and will not exit the attached stripping column.
A continuous stream of unconverted 240db, under-fluorinated intermediates, and some unreacted HF are taken from the bottom of the reactor and fed to a second reactor. Here more of the original reactants and intermediates are converted to 1233xf which exits the top of the attached stripping column. Fresh HF may need to be added. As before a continuous stream of unconverted 240db, under-fluorinated intermediates, and some unreacted HF are taken from the bottom of the second reactor and fed to a third reactor where more is converted. Again fresh HF may need to be added. This reactor train continues in series until the desired production rate of 1233xf is achieved.
Accordingly, an aspect of the invention provides a method for producing a 1233xf comprising:
(a) providing a liquid reaction admixture comprising hydrogen fluoride and 1,1,1,2,3-pentachloropropane, wherein said hydrogen fluoride and 1,1,1,2,3-pentachloro-propane are present in a molar ratio of greater than about 3:1 and
(b) reacting said hydrogen fluoride and 1,1,1,2,3-pentachloropropane in a liquid phase and at a reaction temperature of from about 65° C. to about 175° C. using one or more, preferably two or more, stirred reactors in series to produce reaction product streams comprising 2-chloro-3,3,3-trifluoropropene, hydrogen chloride, unreacted hydrogen fluoride, and optionally unreacted 1,1,1,2,3-pentachloropropane.
Preferably, the method further comprises the steps;
(c) contacting said combined reaction product streams with a heat exchanger to produce:
(i) a first crude product stream comprising a majority of said hydrogen chloride, a majority of said 2-chloro-3,3,3-trifluoropropene, and at least a portion of said unreacted hydrogen fluoride, wherein said portion is an amount sufficient to form an azeotrope with one or more of said 2-chloro-3,3,3-trifluoropropene, and (ii) a reflux component comprising a majority of said unreacted hydrogen fluoride and under-fluorinated intermediates; and
(d) returning said reflux component to said reaction admixture.
In certain preferred embodiments, the method further comprises one or more of the following steps:
(e) separating unreacted reactants, including unreacted 1,1,1,2,3-pentachloropropane and/or under-fluorinated intermediates (e.g., 1,1,2,3-tetrachloro-1-fluoropropane, 1,2,3-trichloro-1,1-difluoropropane, 2,3-dichloro-1,1,1-trifluoropropane, 2,3,3-trichloro-3-fluoropropene (HCFO-1231xf), 2,3-dichloro-3,3-difluoropropene (HCFO-1232xf)) via distillation and recycling these unreacted reactants and under-fluorinated intermediates back to the reactor;
(f) removing at least a portion, and preferably a majority, of hydrochloric acid by-product;
(g) separating and recycling unreacted HF in a crude product stream via a sulfuric acid adsorption or a phase separation; and
(h) distillation of the crude product stream to separate 1233xf from reaction by-products.
According to another aspect of the invention, provided herein is an integrated system for producing 1233xf comprising:
(a) one or more feed streams cumulatively comprising hydrogen fluoride and 1,1,1,2,3-pentachloropropane;
(b) a liquid phase reactor system consisting of a series (train) of two or more agitated reactors each fed by its predecessor, each combined with attached stripping column (supplied with low-temperature cooling), maintained at a first temperature of from about 65° C. to about 175° C., wherein said liquid phase reactor series is fluidly connected to said one or more feed streams;
(c) a stripping system comprising a stripping column, a reflux stream fluidly connected to said stripping column, and a combined first crude product stream fluidly connected to said stripping column, wherein said reflux stream is fluidly connected to said lead liquid phase reactor;
(d) a hydrogen chloride removal system comprising a first distillation column, a hydrogen chloride by-product stream fluidly connected to said first distillation column, and a second crude product stream fluidly connected to said first distillation column, wherein said first distillation column is fluidly connected to said stripping column;
(e) a hydrogen fluoride recovery system comprising a sulfuric acid absorption and recycle system or a phase separation vessel, a second recycle stream comprising hydrogen fluoride fluidly connected to said sulfuric acid absorption and recycle system or a phase separation vessel, a third product stream comprising 2-chloro-3,3,3-trifluoropropene fluidly connected to said sulfuric acid absorption and recycle system or a phase separation vessel, wherein said sulfuric acid absorption and recycle system or a phase separation vessel is fluidly connected to said second crude product stream; and
(f) a 2-chloro-3,3,3-trifluoropropene purification system comprising a second distillation column fluidly connected to said third product stream; a final product stream comprising 2-chloro-3,3,3-trifluoropropene fluidly connected to said second distillation column; a second by-product stream fluidly connected to said distillation column.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a schematic depiction of an integrated liquid phase synthesis of 1233xf according to a preferred embodiment of the invention; and
FIG. 2 shows a schematic depiction of an integrated liquid phase synthesis of 1233xf according to another preferred embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
In preferred embodiments, the invention involves a fully integrated manufacturing process for making 2-chloro-3,3,3-trifluoropropene (1233xf) as described below.
The reaction chemistry for this process involves a single-step reaction of 1,1,1,2,3-pentachloropropane with anhydrous HF in a liquid-phase, uncatalyzed reactor to produce primarily 2-chloro-3,3,3-trifluoropropene (1233xf) plus HCl as a by-product.
Preferably, the reaction is maintained under conditions (temperature, pressure, residence time) to increase yield of 1233xf. Accordingly, the desired reactions involve:
Undesired reactions, which are preferably avoided, include:
In certain embodiments, the manufacturing process comprises five major unit operations:
(1) fluorination reaction (continuous or semi-batch mode) using HF with simultaneous removal of by-product HCl and the product 1233xf,
(2) recycle of unreacted 240db and HF together with under-fluorinated by-products back to (1),
(3) separation and purification of by-product HCl,
(4) separation of excess HF back to (1), and
(5) purification of final product, 1233xf.
The relative positions of these operations in certain preferred embodiments are shown in FIGS. 1 and 2 .
(1) Reactor and Stripping Column
Preferably the reactor is constructed from materials which are resistant to the corrosive effects of the HF and HCl, such as Hastelloy-C, Inconel, Monel, Incoloy, or fluoropolymer-lined steel vessels. The reactor is equipped with an agitator. Such liquid-phase fluorination reactors are well known in the art. The reactor is equipped with a stripping column which permits the desired product to leave, along with by-product HCl, traces of light organics (principally 245cb and 244bb), and sufficient anhydrous hydrogen fluoride (AHF) to form the azeotropes, while retaining the bulk of the HF, plus under-fluorinated organics.
In preferred embodiments more than one fluorination reactors are connected in a series to increase throughput. In a preferred embodiment, the reaction is conducted in a train of agitated, temperature-controlled reactors connected in a series and containing liquid reactants. One or more feeds comprising hydrogen fluoride and 1,1,1,2,3-pentachloropropane enters the first reactor where they contact each other in a liquid phase.
The resulting reaction produces a gas phase product comprising 1233xf as well as various other by-products including HCl, some under-fluorinated intermediates, and a small amount of over-fluorinated by-products. The gas phase product leaves the liquid phase reactor and enters an integrated stripping column (operating in reflux mode) which permits the desired product to leave (along with by-product HCl, over-fluorinated by-products and traces under-fluorinated intermediates, and sufficient anhydrous hydrogen fluoride (AHF) to at least form the azeotropes), while retaining the bulk of the HF, plus under-fluorinated organics.
The products exiting the top of the stripping column are fed into recycle column (2). The stream of under-fluorinated reaction products and unreacted 240db and HF is taken from the bottom of the first fluorination reactor and fed together with required amount of fresh HF to the second fluorination reactor that is operated similar to first fluorination reactor. In some embodiments more than two reactors are connected in the series. The stream from the bottom of the last fluorination reactor is fed to the recycle column (2).
HF and 240db can be charged to the fluorination reactor and the reaction can be initiated immediately upon heating to the desired reaction temperature. The flow of HF to the first fluorination reactor can be established, and addition of the 1,1,1,2,3-pentachloropropane can be started immediately to cause continuous reaction.
Alternatively, a large amount of the same 1,1,1,2,3-pentachloropropane can be added at one time as a batch charge, and then HF can be added gradually to the reactor (a semi-batch operation). Alternatively, a large amount of HF can be added at one time as a batch charge, and then the same 1,1,1,2,3-pentachloropropane can be added gradually to the reactor (a semi-batch operation).
In some embodiments utilizing multiple fluorination reactors connected in a series, the HF can be fed to all of the reactors to maintain proper ratio of HF to organics. Proper temperature control of the coolant and sufficient reflux action are desirable for optimum operation of the stripping column to be effective.
General operating conditions which have been found to work well for the reaction and stripping column are: Operating pressure of 100 psig to 500 psig maintained by a control valve on the exiting flow from the stripping column; reactor temperature of 65° C. to 175° C., primarily supplied by steam flow into the reactor jacket; application of −40° C. to −25° C. brine cooling to the heat exchanger on top of the stripping column to induce reflux; temperature in the center portion of the stripper from about 5° C. to 60° C. below that in the reactor; additional heat input by superheating the HF feed with high-pressure steam to 70° C. to 180° C.
It has been discovered that maintaining the reaction under the operating conditions, particularly, a temperature range of 65° C. to 175° C., more preferably 85° C. to 155° C., and most preferably 95° C. to 150° C., which produces 1233xf in high yield.
(2) Recycle Column
The stream exiting the top of stripping columns attached to the fluorination reactors comprising mainly 1233xf, HF, and HCl (with some minor components including partially fluorinated intermediates and by-products, over-fluorinated by-products), then enters a recycle column. The stream of unreacted HF and 240db, under-fluorinated by-products from the bottom of last fluorination reactor is also fed to the recycle column.
A stream comprising mainly unreacted 1,1,1,2,3-pentachloropropane, partially fluorinated intermediates, and the majority of the HF exits the bottom of the recycle column and is recycled back to the first liquid phase reactor. Optionally it can be fed to any of the reactor in the series. A stream comprising mainly 1233xf, HF, and HCl exits the top of the recycle column and enters HCl recovery column.
(3) Removal of HCl
The HCl formed continuously during the reaction is removed from the reactor due to its volatile nature, and flows through the attached distillation column without condensing. The material can then be purified and collected for sale (or further purification) by using a low-temperature HCl distillation column. High purity HCl is isolated and can be absorbed in de-ionized water as concentrated HCl for sale.
(4) Separation and Recycle of Excess HF Back to (1)
The bottoms stream from the HCl removal column (3) that contains crude product mixture of 1233xf and HF (in some embodiments about 30 wt % 1233xf) is fed to a sulfuric extractor or a phase separator for removal of HF from this mixture. HF is either dissolved in the sulfuric acid or phase separated from the organic mixture. For embodiments utilizing a sulfuric acid adsorption system, the HF is then desorbed from the sulfuric acid/HF mixture by stripping distillation and recycled back to the reactor. For embodiments utilizing a phase separator, HF is phase-separated and recycled back to the reactor. The organic mixture either from the overhead of the sulfuric acid extractor or from the bottom layer of the phase separator may require treatment (scrubbing or adsorption) to remove traces of HF before it is fed to the next unit operation (5).
(5) Purification of Final Product—1233xf
Purification of final product preferably comprises two continuously operating distillation columns. The first (1 st ) column is used to remove light ends from the 1233xf and the second (2 nd ) column is used to remove the heavier components, primarily the under-fluorinated intermediates, which are recycled to fluorination reactor (1) or collected for further use or disposal. In certain embodiments, it is desirable to have a purge of heavy by-products from this stream.
Referring to FIG. 1 , shown is the synthesis of 1233xf via a liquid phase reaction integrated process utilizing three reactors connected in series (R-1, R-2, and R-3), having sulfuric acid HF recovery, and recycle column after the reactors. Here, liquid phase reactor R-1 is first charged with an required amounts of anhydrous hydrogen fluoride and 1,1,1,2,3-pentachloropropane. Preferably the reactor is constructed from materials which are resistant to the corrosive effects of the HF and HCl, such as Hastelloy-C, Inconel, Monel, Incoloy, or fluoropolymer-lined steel vessels. Such liquid-phase fluorination reactors are well known in the art. After reactor is charged with HF and 240db an agitator is turned on to achieve a good agitation.
The reaction mixture is then heated to about 85° C. to 150° C. where the fluorination reaction between 1,1,1,2,3-pentachloropropane and HF is initiated. Continuous 1,1,1,2,3-pentachloropropane and HF (in a stoichiometric excess) feeds are simultaneously fed to heater HX-1 and then into a liquid phase reactor R-1. Optionally, 1,1,1,2,3-pentachloro-propane is fed directly into reactor R-1 and not through heater HX-1.
The operating pressure of R-1 is in the range of 75 psig to 500 psig (preferably 185 psig to 400 psig) is maintained by a control valve on the exiting flow from the stripping column RC-1 and the reactor temperature is kept in the range of 65° C. to 175° C. (preferably 100° C. to 140° C.) primarily supplied by steam flow into the reactor jacket. A stripping column RC-1 is connected to the reactor, R-1, and serves the purpose of knocking down and returning some HF, partially fluorinated intermediates, and some unreacted 1,1,1,2,3-pentachloropropane back to the reactor for further reaction.
The stream exiting the top of stripping RC-1 comprising mainly 1233xf, HF, and HCl (with some minor components including partially fluorinated intermediates and by-products, and over-fluorinated by-products), then enters then enters recycle column D-1.
When the desired level in the first fluorination reactor is achieved a stream of unreacted HF, unreacted 1,1,1,2,3-pentachloropropane, and under-fluorinated intermediates is fed to second fluorination reactor R-2. The feed of fresh HF is also fed to R-2 to maintain proper HF to organics ratio. Reactor R-2 is equipped with stripping column RC-2 that is operated similar to RC-1. Reactor R-2 is maintained at a temperature of from 115° C. to 150° C. and a pressure of from about 170 psig to 425 psig.
The stream exiting the top of stripping RC-2 comprising mainly HCFO-1233xf, HF, and HCl (with some minor components including partially fluorinated intermediates and by-products, and over-fluorinated by-products), then enters then enters recycle column D-1.
When the desired level in the second fluorination reactor is achieved a stream of unreacted HF, unreacted 1,1,1,2,3-pentachloropropane, and under-fluorinated intermediates is fed to third fluorination reactor R-3. The feed of fresh HF is also fed to R-3 to maintain proper HF to organics ratio. Reactor R-3 is equipped with stripping column RC-3 that is operated similar to RC-1 and RC-2. Reactor R-3 is maintained at a temperature range of 125° C. to 160° C. and pressure range of about 160 psig to 450 psig.
The stream exiting the top of stripping RC-3 comprising mainly 1233xf, HF, and HCl (with some minor components including partially fluorinated intermediates and by-products, and over-fluorinated by-products), then enters recycle column D-1.
When the desired level in the third fluorination reactor is achieved a stream of unreacted HF, unreacted 1,1,1,2,3-pentachloropropane, and under-fluorinated intermediates is fed to the recycle column D-1. Optionally, heavy by-products are removed from this stream by establishing a small heavies purge continuous or intermittent side stream.
The recycle column D-1 is operated in a such a way that a stream comprising mainly unreacted 1,1,1,2,3-pentachloropropane, partially fluorinated intermediates, and the majority of the HF exits the bottom of the recycle column and is recycled back to the liquid phase reactor R-1 via vaporizer HX-1. A stream comprising mainly 1233xf, HF, and HCl exits the top of the recycle column and enters HCl column D-2. A stream comprising mainly HCl by-product exits the top of the HCl column and is fed to an HCl recovery system. The recovered HCl by-product can be sold for profit.
The HCl column bottoms stream consisting mainly of 1233xf and HF are then fed into an HF recovery system. The HF recovery system starts with the crude 1233xf/HF stream being vaporized in heat exchanger HX-2 and fed into HF absorption column A-1. Here a liquid stream of 50% to 80% H 2 SO 4 contacts the gaseous 1233xf/HF stream and absorbs the majority of the HF. The stream exiting the bottom of A-1 comprises HF/H 2 SO 4 /H 2 O and is fed to heat exchanger HX-3 where it is heated to a temperature sufficient to flash the majority of the HF along with small amounts of H 2 O and H 2 SO 4 . This stream is fed to HF recovery distillation column D-2. The liquid remaining after the HF is flashed off in HX-3 consisting mainly of H 2 SO 4 and H 2 O (with 0 to 2% HF) is cooled in HX-4 and recycled back to HF absorption column A-1.
The HF recovery column, D-3, bottoms stream comprising mainly H 2 SO 4 and H 2 O are recycled back to heat exchanger HX-3 Anhydrous HF is recovered from the top of the HF recovery column, D-3, and is recycled back to the reactor R-1 via vaporizer HX-1. The stream exiting the top of HF absorption column A-1 comprising mainly 1233xf (trace HF) is sent forward to a polishing system A-2 where the gaseous stream contacts a water or a caustic solution to remove trace HF and is subsequently dried with a desiccant.
Acid free crude product exiting absorber A-2 is sent to the first of two purification columns, D-4. A stream exiting the top of the column D-4 consists mainly of reaction by-products that have boiling points lower than that of 1233xf. The stream exiting the bottom of lights column D-4 consisting mainly of 1233xf and heavier by-products is fed to product recovery distillation column D-5. Product grade 1233xf exits the top of the column to product storage. The product column bottoms consist mainly of reaction by-products with boiling points higher than that of 1233xf is then fed to vaporizer HX-1 and then fluorination reactor R-1.
Referring to FIG. 2 , shown is the synthesis of 1233xf via a liquid phase reaction integrated process utilizing three reactors connected in series (R-1, R-2, and R-3), a phase separation HF recovery system, and recycle column after the reactor. Here, liquid phase reactor R-1 is first charged with an required amounts of anhydrous hydrogen fluoride and 1,1,1,2,3-pentachloropropane. Preferably the reactor is constructed from materials which are resistant to the corrosive effects of the HF and HCl, such as Hastelloy-C, Inconel, Monel, Incoloy, or fluoropolymer-lined steel vessels. Such liquid-phase fluorination reactors are well known in the art. After reactor is charged with HF and 240db an agitator is turned on to achieve a good agitation.
The reaction mixture is then heated to about 85° C. to 150° C. where the fluorination reaction between 1,1,1,2,3-pentachloropropane and HF is initiated. Continuous 1,1,1,2,3-pentachloropropane and HF (in a stoichiometric excess) feeds are simultaneously fed to heater HX-1 and then into a liquid phase reactor R-1.
Optionally, 1,1,1,2,3-pentachloropropane is fed directly into reactor R-1 and not through heater HX-1. The operating pressure of R-1 is in the range of 75 psig to 500 psig (preferably 185 psig to 450 psig) is maintained by a control valve on the exiting flow from the stripping column RC-1 and the reactor temperature is kept in the range of 65° C. to 175° C. (preferably 100° C. to 140° C.) primarily supplied by steam flow into the reactor jacket. A stripping column RC-1 is connected to the reactor, R-1, and serves the purpose of knocking down and returning some HF, partially fluorinated intermediates, and some unreacted 1,1,1,2,3-pentachloropropane back to the reactor for further reaction.
The stream exiting the top of stripping RC-1 comprising mainly 1233xf, HF, and HCl (with some minor components including partially fluorinated intermediates and by-products, and over-fluorinated by-products), then enters then enters recycle column D-1.
When the desired level in the first fluorination reactor is achieved a stream of unreacted HF, unreacted 1,1,1,2,3-pentachloropropane, and under-fluorinated intermediates is fed to second fluorination reactor R-2. The feed of fresh HF is also fed to R-2 to maintain proper HF to organics ratio. Reactor R-2 is equipped with stripping column RC-2 that is operated similar to RC-1. Reactor R-2 is maintained at a temperature range of 115° C. to 150° C. and pressure range of about 170 psig to 425 psig.
The stream exiting the top of stripping RC-2 comprising mainly 1233xf, HF, and HCl (with some minor components including partially fluorinated intermediates and by-products, and over-fluorinated by-products), then enters then enters recycle column D-1.
When the desired level in the second fluorination reactor is achieved a stream of unreacted HF, unreacted 1,1,1,2,3-pentachloropropane, and under-fluorinated intermediates is fed to third fluorination reactor R-3. The feed of fresh HF is also fed to R-3 to maintain proper HF to organics ratio. Reactor R-3 is equipped with stripping column RC-3 that is operated similar to RC-1 and RC-2. Reactor R-3 is maintained at a temperature range of from 125° C. to 160° C. and pressure range of from about 160 psig to 450 psig.
The stream exiting the top of stripping RC-3 comprising mainly 1233xf, HF, and HCl (with some minor components including partially fluorinated intermediates and by-products, and over-fluorinated by-products), then enters then enters recycle column D-1.
When the desired level in the third fluorination reactor is achieved a stream of unreacted HF, unreacted 1,1,1,2,3-pentachloropropane, and under-fluorinated intermediates is fed to the recycle column D-1. Optionally, heavy by-products are removed from this stream by establishing a small heavies purge continuous or intermittent side stream.
The recycle column D-1 is operated in a such a way that a stream comprising mainly unreacted 1,1,1,2,3-pentachloropropane, partially fluorinated intermediates, and the majority of the HF exits the bottom of the recycle column and is recycled back to the liquid phase reactor R-1 via vaporizer HX-1. A stream comprising mainly 1233xf, HF, and HCl exits the top of the recycle column and enters HCl column D-2. A stream comprising mainly HCl by-product exits the top of the HCl column and is fed to an HCl recovery system. The recovered HCl by-product can be sold for profit. The HCl column bottoms stream consisting mainly of 1233xf and HF are then fed into an HF recovery system.
The HF recovery system starts with the 1233xf/HF stream being fed into heat exchanger HX-2 where it is pre-cooled to temperatures below 0° C. and then enters phase separation vessel PS-1. Here the stream temperature is maintained or further cooled to −40° C. to 0° C. The HF rich top layer (less than 10% 1233xf) is recycled back to the liquid phase reactor R-1. The organic rich bottom layer containing mainly 1233xf (less than 4% HF) is sent to vaporizer HX-3 and then forward to a polishing system A-1 where the gaseous stream contacts water or a caustic solution to remove trace HF and is subsequently dried with a desiccant. Acid free crude product exiting absorber A-1 is sent to the first of two purification columns, D-3.
A stream exiting the top of the column D-3 consists mainly of reaction by-products that have boiling points lower than that of 1233xf. The stream exiting the bottom of lights column D-3 consisting mainly of 1233xf and heavier by-products is fed to product recovery distillation column D-4. Product grade 1233xf exits the top of the column to product storage. The product column bottoms consist mainly of reaction by-products with boiling points higher than that of 1233xf is then fed to vaporizer HX-1 and then to fluorination reactor R-1.
Optionally, the stream exiting the bottom of the product recovery distillation column, D-4 can be recycled back to first liquid phase reactor R-1. In any of these options a heavies purge stream from the bottom of the product recovery distillation column, D-4, will be required to prevent build-up of high boiling impurities in the purification system. The heavies purge stream is collected for later use or waste disposal.
EXAMPLES
Example 1
As part of the development of a liquid phase process for making 1233xf an experiment is run using no catalyst. The experiment is run in a 1-gallon Parr reactor in a batch mode. For the experiment 282.9 grams of HF and 246.2 grams of 240db (1,1,1,2,3-pentachloropropane) (12.4 to 1 mole ratio HF:240db) are charged to the reactor at room temperature. The mixer is then turned on ensuring the reactor contents were well mixed. Then the reactor is heated to the desired temperature. Upon heating the pressure begins to rise as HCl by product is produced as a result of a fluorination reaction.
The reactor is heated to about 110° C. over several hours and then the temperature is held constant. The pressure is controlled in the range of 250 psig to 325 psig by venting off the HCl generated in the reaction to a dry-ice chilled dry ice trap (DIT). At the completion of the reaction after about 9.5 hours, which is determined by lack of HCl generation, the pressure from the reactor is vented into the DIT. The crude product from DIT is transferred into a 1 L Monel absorption cylinder (frozen in dry-ice) with about 400 grams of water. The absorption cylinder is allowed to warm up to room temperature and a sample of an organic layer that has formed in the cylinder (aqueous and organic layers are present in the cylinder upon discharge) is taken and analyzed by GC.
GC results show 0.42 GC % 245cb, 97.23 GC % 1233xf, 1.39 GC % 244bb, balance under-fluorinated intermediates (241db and 242db). The amount of organic collected is later quantified by further analysis of the different phases and amounted to 75.0 grams.
The organic remaining in the reactor after venting is recovered by quenching the reactor with about 300 grams to 400 grams of water to absorb HF and HCl, and then adding about 100 grams of carbon tetrachloride. The reactor is then opened and its contents discharged into a plastic bottle. The organic is separated from the aqueous phase by use of a separatory funnel. The amount of heavies collected from the reactor is calculated by subtracting the weight of CCl 4 added to the reactor from the total weight of organic phase collected and amounts to 96.9 grams.
GC/MS and GC analysis of the organic layer reveals 3 distinct peaks attributed to under-fluorinated species 241db, 91.057 GC %, 242dc, 0.760 GC %, and the starting material 240db, 8.183 GC %. The overall conversion of 240db was calculated to be 97%.
Example 2
The experiment described in Example 1 is repeated using the same equipment and procedure. The reactor is heated to 110° C. and held. However, the experiment is not allowed to go to completion. After about 6.5 hours the reactor pressure reaches 320 psig and the experiment is stopped. 382.7 grams of HF and 244.1 grams of 240db are initially charged to the reactor. As shown below in Table I, the results are similar to those of Example 1, but with a lower conversion of 240db.
TABLE I
Charged to reactor
Weight (moles)
HF
392.7 grams (16.485 moles)
240db
244.1 grams (1.129 moles)
Collected reaction products
Weight
Volatile products form DIT
76.1 grams
(0.2 GC % 245cb, 97.5 GC % 1233xf, 2.1
GC % 244bb (balance 241db and 242dc)
Heavies from reactor
121.4 grams (1.713 GC % 242db, 58.691
GC % 241db, 39.596 GC % 240db)
Comparative Example 1
This comparative example shows that 240db is more stable than its unsaturated derivatives such as tetrachloropropenes in the presence of hydrogen fluoride at elevated temperatures.
As part of the development of a liquid phase process for making 1233xf an experiment was run using 1,1,2,3-tetrachloropropene as a starting material. The experiment used the same a 1-gallon Parr reactor as described in Examples 1 and 2 and was run in a batch. The empty reactor was first charged with 327 grams of 1,1,2,3-tetracholopropene. Then 557.5 grams of HF were charged into the reactor at room temperature. The mixer was then turned on ensuring the reactor contents were well mixed. Then the reactor was heated to 149° C.
Upon heating the pressure began to rise as HCl by product was produced as a result of a fluorination reaction. The pressure was controlled in the range of 490 psig to 497 psig by venting off the HCl generated in the reaction to a dry-ice chilled DIT. The reactor was held at 149° C. for about 4 hours. The volatile reaction products collected in the DIT and the reactor residue were worked up and analyzed the same way as described in Example 1. Analysis of the reaction products revealed that the selectivity to 1233xf was about 20%. Remaining 80% of 1,1,2,3-tetrachloropropene starting material were converted to unknown tar-like compounds. This comparative example shows the benefits of starting with saturated chloroalkane, HCC-240db, as no tar-like by-products were observed in Example 1 when the reaction was run at similar conditions.
Comparative Example 2
This comparative example shows that the use of a fluorination catalyst for the fluorination reaction of 240db to 1233xf results in the formation of a large amount of oligomers, dimers, and tars.
As part of the development of a liquid phase process for making 1233xf an experiment was run using a liquid phase fluorination catalyst. The experiment used a 1 liter agitated autoclave and was run in a batch mode and was called Exp #4. The empty reactor was first charged with 84.3 grams of SbCl 5 liquid fluorination catalyst. Then 402.6 grams of HF was charged into the reactor at room temperature which was immediately followed by a pressure rise in the reactor due to the generation of HCl as the catalyst became fluorinated.
After venting the pressure (HCl) resulting from the reaction of HF with the catalyst, 152.3 grams of HCC-240db was charged to reactor. The mixer was then turned on ensuring the reactor contents were well mixed. Then the reactor was heated to 90° C. Upon heating the pressure began to rise as HCl by product was produced as a result of a fluorination reaction. The pressure was controlled in the range of 325 psig to 330 psig by venting off the HCl generated in the reaction to a dry-ice chilled trap. The reactor was held at 90° C. for about 1 hour.
The volatile reaction products collected in the DIT and the reactor residue were worked up and analyzed the same way as described in Example 1. The volatile reaction products were the same as those from the experiments run without catalyst described in Examples 1 and 2, but the organic remaining in the reactor after venting were different. This time the organic layer (CCl 4 with dissolved organic) was a dark brown/black color and was much more viscous than the organic layer collected in the non catalytic experiments and GC analysis indicated the presence of multiple oligomeric by-products and tars. No HCC-240db or under-fluorinated species, HCFC-241db and HCFC-242db, were present.
Experimental conditions and results of GC analysis of the reaction products are presented in the Table II below.
TABLE II
Collected reaction products
Weight (moles)
SbCl 5
84.3 grams (0.282 moles)
HF
302.6 grams (15.13 moles)
240db
152.3 grams (0.704 moles)
Weight
Volatile products form DIT
62.3 grams
(11.06 GC % 245cb, 11.0 GC % 1233xf,
16.2 GC % 244fa, 13.7 GC % 1223xd, 10.4
C 6 H 3 Cl 2 F 7 GC area %, 37% unknowns)
Heavies from reactor
43.7 grams (multiple oligomers and tars)
Example 3
A series of three (3) continuously stirred reactors with attached stripping columns is used to produce crude 1233xf product. There is a bottom drain on the first reactor that feeds the second reactor and a drain on the second reactor that feeds the third reactor. The overhead stream that exits each of the three stripping columns are connected to combine all 1233xf crude and HCl produced and fed forward for separation into individual components.
To the lead (first) reactor is continuously fed a 15:1 mole ratio of HF:240db. The reactor temperature is maintained at about 140° C. The reactor pressure is controlled at about 400 psig. HF, HCl, and crude 1233xf exit the top of the attached stripping column continuously. The reactor is drained continuously to the second reactor at a rate that maintains a near constant level in the reactor. The lead reactor achieves a 70% conversion of 240db and a yield of 50% of 1233xf crude. The organic composition of the material being drained to the second reactor is about 40% 240db, 55% 241db, and 5% 242db. HF is also present in this stream. Fresh HF is added to the second reactor to make up for rectifier column overhead losses.
The second reactor is run at a 375 psig and is maintained at 135° C. HF, HCl, and crude 1233xf exit the top of the attached stripping column continuously. The reactor is drained continuously to the third reactor at a rate that maintains a near constant level in the reactor. The second reactor achieves a 90% conversion of 240db and a yield of 70% of 1233xf crude. The organic composition of the material being drained to the second reactor is about 33% 240db, 62% 241db, and 5% 242db. HF is also present in this stream. Fresh HF is added to the third reactor to make up for rectifier column overhead losses.
The third reactor is run at a 350 psig and is maintained at 130° C. HF, HCl, and crude 1233xf exit the top of the attached stripping column continuously. The reactor is drained continuously to a recycle column at a rate that maintains a near constant level in the reactor. The third reactor achieves a 100% conversion of 240db and a yield of 95% of 1233xf crude. The organic composition of the material being drained to the recycle column is about 95% 241db, and 5% 242db. HF is also present in this stream.
Example 4
This example demonstrates the recycle column operation which recovers excess HF, unreacted 240db, and under-fluorinated intermediates for recycle back to the reactor.
The reactor effluent stream from a fluorination reactor producing 1233xf was continuously fed directly to a recycle distillation column. The stream contained HF, HCl, and 1233xf crude product. The crude product contained some over-fluorinated intermediates, under-fluorinated intermediates, and unreacted organic feed stock. The distillation column consisted of a 10 gallon reboiler, 2 inch ID by 10 foot column packed with propack distillation packing and a shell and tube condenser. The column had about 30 theoretical plates. The distillation column was equipped with reboiler level indicator, temperature, pressure, and differential pressure transmitters.
The distillation column was run continuously at pressure of about 60 psig and differential pressure of about 15 inches of H 2 O. The stream exiting overhead from the top of the column consisted of HCl, over-fluorinated intermediates, 1233xf, and some of the HF. A GC analysis of the organic portion of the stream showed the purity of 1233xf was greater than 99 GC area %.
The stream exiting the bottom of the reboiler consisted of HF, under-fluorinated intermediates, and unreacted organic feed stock and were recycled back to the fluorination reactor.
Example 5
This example illustrates the recovery of anhydrous HF from a mixture of HF and 1233xf according to certain preferred embodiments of the present invention.
A mixture consisting of about 75 wt. % 1233xf and about 25 wt. % HF is vaporized and fed to the bottom of a packed column at a feed rate of about 2.9 lbs per hour for about 4 hours. A stream of about 80 wt. % sulfuric acid (80/20 H 2 SO 4 /H 2 O) with about 2% HF dissolved therein is fed continuously to the top of the same packed column at a feed rate of about 5.6 lbs per hour during the same time frame. A gaseous stream exiting the top of the column comprises 1233xf with less than 1.0 wt. % HF therein. The concentration of HF in the sulfuric acid in the column bottoms increases from 2.0 wt. % to about 15 wt. %.
The column bottoms containing sulfuric acid and about 15 wt. % HF are collected and charged into a 2 gallon teflon vessel. The mixture is heated to about 140° C. to vaporize and flash off the HF product, which is collected. The collected HF product contains about 6000 ppm water and 500 ppm sulfur.
The HF collected from flash distillation is distilled in a distillation column and anhydrous HF is recovered. The recovered anhydrous HF contains less than 50 ppm of sulfur impurities and less than 100 ppm water.
Example 6
This example illustrates the phase separation of a mixture of 1233xf and HF which form a heterogeneous mixture.
60.77 grams of crude 1233xf and 34.91 grams of HF were mixed together in a Teflon cell and 2 liquid phases were visually observed. The mixture was allowed to sit until it reached ambient temperature of about 24° C. The upper and lower phases were sampled and analyzed by Ion Chromatography to determine HF concentration. The lower organic rich layer had 2.2 wt % HF and the upper HF rich layer had 62.96 wt % HF.
Example 7
This example demonstrates the purification of the acid free 1233xf crude product.
120 lbs of 1233xf crude product collected after HCl and HF removal was charged to a batch distillation column. The crude material contained about 96 GC area % 1233xf and 4 GC area % impurities. The distillation column consisted of a 10 gallon reboiler, 2 inch ID by 10 foot column packed with propack distillation packing and a shell and tube condenser. The column had about 30 theoretical plates. The distillation column was equipped with reboiler level indicator; temperature, pressure, and differential pressure transmitters. The batch distillation was run at pressure of about 90 psig and differential pressure of about 17 inches of H 2 O. About 7 lbs of a lights cut was recovered which consisted of mainly 245cb, trifluoropropyne, 244bb, and 1233xf. 110 lbs of 99.9+ GC area % 1233xf were collected. The reboiler residue amounting to about 3 lbs was mainly 244bb, 1233xf, 1232xf, and a C6 compound (dimer). The recovery of 99.8+ GC area % pure 1233zd(E) was 94.8%.
As used herein, the singular forms “a”, “an” and “the” include plural unless the context clearly dictates otherwise. Moreover, when an amount, concentration, or other value or parameter is given as either a range, preferred range, or a list of upper preferable values and lower preferable values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. Where a range of numerical values is recited herein, unless otherwise stated, the range is intended to include the endpoints thereof, and all integers and fractions within the range. It is not intended that the scope of the invention be limited to the specific values recited when defining a range.
It should be understood that the foregoing description is only illustrative of the present invention. Various alternatives and modifications can be devised by those skilled in the art without departing from the invention. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variances that fall within the scope of the appended claims.
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Disclosed is a method for the production of 1233xf comprising the continuous low temperature liquid phase reaction of 1,1,1,2,3-pentachloropropane and anhydrous HF, without the use of a catalyst, wherein the reaction takes place in one or more reaction vessels, each one in succession converting a portion of the original reactants fed to the lead reaction vessel and wherein the reactions are run in a continuous fashion.
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BACKGROUND AND SUMMARY
Engines utilize various types of fuel injection adjustments to provide improved engine performance. One example fuel injection compensation methods increases or decreases fuel injection to account for fuel adhered to walls of the intake manifold, intake valves, and/or intake ports. Such phenomena may be referred to as wall wetting dynamics, or transient fuel dynamics. To compensate for such dynamics, the amount of fuel injected is varied to compensate for the fuel stored in the intake manifold and intake ports based on various models and estimates taking into account engine operating conditions. In this way, more accurate air/fuel ratio control may be achieved in of the combusted air/fuel mixture.
One example of fuel injection control is described in U.S. Pat. No. 5,492,101. In this example, a transient fuel compensation is described that uses an atomized fuel behavioral model, intake passage fuel behavioral model, and a combustion fuel behavioral model to adjust fuel injection and control actual air/fuel ratio in the combustion chamber. Specifically, the approach utilizes a fuel property value (NF) in the intake passage behavioral model.
The inventors herein have recognized several issues with the above approach. First, there may be numerous fuel properties that may be included in the model, some of which may have an influence of increasing fuel injection compensation while others have an influence of decreasing fuel injection compensation. Second, the inventors herein have also recognized that the determination of fuel properties may require additional sensors, thus increasing costs.
In one embodiment, the above issues may be addressed by utilizing fuel volatility to adjust transient fuel injection, where the fuel volatility is determined during previous engine start-up operation. For example, Applicants have recognized that fuel volatility and/or quality can have an impact on air-fuel control during transient fueling conditions by affecting the amount of fuel stored in the intake manifold and ports, the rate of storage, and/or the rate of release. Further, by determining fuel volatility during a start, it is possible to determine an indication of fuel volatility by monitoring engine run-up speed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a vehicle illustrating various powertrain components; and
FIGS. 2–4 are high level flowchart of routines for controlling the engine and fuel injection.
DETAILED DESCRIPTION
Internal combustion engine 10 comprising a plurality of cylinders, one cylinder of which is shown in FIG. 1 , is controlled by electronic engine controller 12 . Engine 10 includes combustion chamber 30 and cylinder walls 32 with piston 36 positioned therein and connected to crankshaft 13 . Combustion chamber 30 communicates with intake manifold 44 and exhaust manifold 48 via respective intake valve 52 and exhaust valve 54 . Exhaust gas oxygen sensor 16 is coupled to exhaust manifold 48 of engine 10 upstream of catalytic converter 20 .
Intake manifold 44 communicates with throttle body 64 via throttle plate 66 . Throttle plate 66 is controlled by electric motor 67 , which receives a signal from ETC driver 69 . ETC driver 69 receives control signal (DC) from controller 12 . Intake manifold 44 is also shown having fuel injector 68 coupled thereto for delivering fuel in proportion to the pulse width of signal (fpw) from controller 12 . Fuel is delivered to fuel injector 68 by a conventional fuel system (not shown) including a fuel tank, fuel pump, and fuel rail (not shown).
Engine 10 further includes conventional distributorless ignition system 88 to provide ignition spark to combustion chamber 30 via spark plug 92 in response to controller 12 . In the embodiment described herein, controller 12 is a conventional microcomputer including: microprocessor unit 102 , input/output ports 104 , electronic memory chip 106 , which is an electronically programmable memory in this particular example, random access memory 108 , and a conventional data bus.
Controller 12 receives various signals from sensors coupled to engine 10 , in addition to those signals previously discussed, including: measurements of inducted mass air flow (MAF) from mass air flow sensor 110 coupled to throttle body 64 ; engine coolant temperature (ECT) from temperature sensor 112 coupled to cooling jacket 114 ; a measurement of throttle position (TP) from throttle position sensor 117 coupled to throttle plate 66 ; a measurement of turbine speed (Wt) from turbine speed sensor 119 , where turbine speed measures the speed of the transmission input shaft, and a profile ignition pickup signal (PIP) from Hall effect sensor 118 coupled to crankshaft 13 indicating an engine speed (N). Alternatively, turbine speed may be determined from vehicle speed and gear ratio.
Continuing with FIG. 1 , accelerator pedal 130 is shown communicating with the driver's foot 132 . Accelerator pedal position (PP) is measured by pedal position sensor 134 and sent to controller 12 .
In an alternative embodiment, where an electronically controlled throttle is not used, an air bypass valve (not shown) can be installed to allow a controlled amount of air to bypass throttle plate 62 . In this alternative embodiment, the air bypass valve (not shown) receives a control signal (not shown) from controller 12 .
As will be appreciated by one of ordinary skill in the art, the specific routines described below in the flowcharts may represent one or more of any number of processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. As such, various steps or functions illustrated may be performed in the sequence illustrated, in parallel, or in some cases omitted. Likewise, the order of processing is not necessarily required to achieve the features and advantages of the disclosure, but is provided for ease of illustration and description. Although not explicitly illustrated, one of ordinary skill in the art will recognize that one or more of the illustrated steps or functions may be repeatedly performed depending on the particular control strategy being used. Further, these Figures graphically represent code to be programmed into the computer readable storage medium in controller 12 .
Referring now to FIG. 2 , a routine is described showing when a fuel volatility/ or fuel quality determination may be performed. In 210 , the routine first determines whether an engine start is present. For example, an engine start may be determined via the engagement of an engine starter motor, monitoring whether engine speed is greater than a minimum engine speed, a driver key position or various others. When answer to 210 is yes, the routine continues to 212 . In 212 , the routine determines whether the time since the engine start is greater than a threshold value. The time since the engine start may be determined in various ways such as, the amount of time after the engine has reached a minimum speed such as 250 rpm. When the answer to 212 is no, the routine continues to 214 . In 214 , the routine determines whether a driver tip-in has occurred and whether the engine idle speed is stabilized. A driver tip-in can be determined in various ways such as, based on whether the driver accelerator pedal position is greater than a threshold value. Further, stable engine idle speed may be determined by comparing the measured engine idle speed to the desired engine idle speed and determine whether it has remained within a given threshold for a given number of engine cycles. If the answer to 214 is no, the routine continues to 216 . In 216 the routine determines whether close loop air/fuel ratio control is enabled. For example, the routine may determine whether exhaust gas oxygen sensors have reached a desired operating temperature, in which case fuel injection is adjusted based on feedback from the exhaust gas oxygen sensors. If the answer to 216 is no, the routine continues to 218 . In 218 , the routine determines whether the engine temperature, such as the engine coolant temperature (ECT) is within a specified operating window. If the answer to 218 is yes, the routine continues to 220 to perform the routine of FIG. 3 .
Alternatively, in each of the above cases, the routine continues to the end.
Turning now to the control strategy depicted in FIG. 3 , a routine for determining a parameter indicative of fuel volatility is described. Alternatively, various other determinations may be made, such as based on a fuel quality sensor, such as fuel density, viscosity, or combinations thereof. In general, the routine of FIG. 3 uses a proportional and derivative speed feedback control to compensate for variations in fuel volatility during an engine start, where the deviation between an expected and actual engine run-up speed profile is used as an indication of the fuel volatility.
Continuing with FIG. 3 , the first step is to calculate the expected engine speed run-up profile. In this example, the expected speed is determined as a minimum of two parameters at 312 . The first parameter 308 is determined at 310 as a function of engine coolant temperature (ECT), which is represented by the average ECT during the engine start and time out of engine cranking. The time out of engine cranking, or time since start can be, for example, a timer starting after engine speed reaches a minimum threshold, such as approximately 250 RPM. The second variable is a desired idle RPM value, which may be determined by an idle speed control routine (not shown).
Next, the expected engine speed is compared with the actual engine speed at the summing junction of 314 . The result of this comparison and an approximate derivative of measured engine speed (e.g., the filtered slope of the speed curve) from 326 are fed to 316 . An example filter that may be used to approximate the derivative is a simple first order filter. In 316 , the input values are used to calculate a fractional value (from 0 to 1), where 1 is the maximum output and 0 is the minimum output. The output is then fed to 318 and 320 and filtered depending on the direction of the change. If the output is increasing, no filtering is used ( 318 ); however, if the output is decreasing, a simple first order low-pass filter may be used ( 320 ). The output of 318 / 320 is a parameter indicative of a fuel quality, such as the amount of hesitation type fuel present during the start.
This parameter may then be used to adjust engine operation, such as to adjust a fuel injection amount and/or spark timing via 322 and 324 , respectively. For example, this parameter indicative of fuel quality may be used to adjust the desired air-fuel ratio and spark timing. In one example, the parameter is used to adjust the desired air-fuel ratio by increasing the richness of the air-fuel ratio as the parameter increases, where various levels of gain may be used depending on operating conditions. The spark timing may be adjusted by blending spark timing between a base timing (for starting with a minimum fuel quality level) and a maximum limit on spark timing after which torque is reduced.
In this way, the potentially lean combustion caused by degraded fuel quality may be compensated by richening the fuel injection and advancing spark timing (from its retarded value during an engine start to provide rapid catalyst heating).
Referring now to FIG. 4 , a routine is described for utilizing the parameter indicative of fuel quality or fuel volatility in adjusting a transient fuel adjustment. First, in 410 , the routine identifies the peak, or maximum, fuel volatility parameter output from blocks 318 – 320 of FIG. 3 during the most recent engine start. Alternatively, rather than using the most recent engine start value the routine may average a plurality of previous engine start fuel volatility parameters to identify the peak fuel volatility indication in 410 . Next, in 412 , the routine determines whether the peak value of 410 is below a minimum noise threshold. If so, the routine continues to 414 , and no compensation to the transient fuel adjustment values are made, and the routine continues to the end.
Alternatively, when the answer to 412 is no, the routine continues to 416 . In 416 , the routine determines whether the peak value from 410 is above a saturation threshold value. If so the routine continues to 418 to clip the fuel volatility parameter to a maximum saturation value. From either 418 , or when the answer to 416 is no, the routine continues to 420 . In 420 , the routine determines various adjustments to transient fuel parameters at different engine coolant temperatures, for example. For example, the routine may adjust a ratio of injected fuel that is stored in the intake manifold for a given coolant temperature based on the detected peak fuel volatility indication. Alternatively, or in addition, the routine may also adjust the ratio of fuel evaporating from puddles in the intake manifold or intake ports that is inducted into a cylinder during the induction stroke based on the peak volatility parameter. Still further, other adjustments to gains and/or time constant of the transient fuel compensation algorithms can be made based on the peak detected fuel volatility indication from FIG. 3 .
Continuing with FIG. 4 , in 422 , the routine performs the transient fuel calculation and fuel injection adjustment based on engine operating parameters.
In this way, it is possible to adjust transient fuel injection adjustment to account for variations in fuel quality where the fuel quality may be identified during an engine start.
In one embodiment, the captured volatility information may be used even during the engine start, although the final maximum value over the entire start is not yet identified. In other words, the routine may use the maximum value up to the current conditions during a start to adjust transient fuelling operation. Alternatively, the routine may wait to identify the maximum value before enabling adjustment of transient fuelling operation after the engine start.
It will be appreciated that the configurations and routines disclosed herein are exemplary in nature, and that these specific embodiments are not to be considered in a limiting sense, because numerous variations are possible. For example, the above approaches can be applied to V-6, I-4, I-6, V-12, opposed 4, and other engine types.
The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various systems and configurations, and other features, functions, and/or properties disclosed herein.
The following claims particularly point out certain combinations and subcombinations regarded as novel and nonobvious. These claims may refer to “an” element or “a first” element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.
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A method for adjusting fuel injection, the method comprising during an engine start from a non-warmed-up condition, identifying a fuel quality of fuel supplied to the engine during said start based on a performance of said start, and after said start is completed and during a transient fueling condition, adjusting a fuel injection amount based on said identified fuel quality from said start.
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BACKGROUND OF THE INVENTION
This invention relates to protective systems for firearms, and more specifically, a method and apparatus for preventing dirt and moisture from entering into the firing mechanism of a firearm.
Military weapons often find use in harsh geographical conditions. For instance, the windblown sand environment found in deserts, such as in Saudi Arabia, is probably the worst case situation for weapon contamination. The fine desert sand can find its way into every orifice of a rifle or other firearm. While little damage or operational interference will result from sand intrusion into many of the weapons openings, two openings present direct access to the weapons operating system where sand or water could and would most likely cause catastrophic system failure. The two areas of concern are, the magazine well when an ammunition magazine is not attached, and the muzzle end of the rifle.
As an example, the M16A2 rifle is a superior combat weapon designed and produced to exacting tolerances. Like all closed bolt rifles, however, the M16A2 is susceptible to malfunction when contaminants such as sand, dirt or mud find their way into the weapons' operating mechanism.
Therefore, it is an object of the present invention to provide a method and apparatus for preventing contaminants from entering the open muzzle of the rifle or an open magazine well of the rifle, when the weapon is not in use.
It is a further object of the present invention to provide a method and apparatus for preventing entry of contaminants into an unused weapon, which may be easily and quickly removed to meet the requirements of combat conditions.
It is a further object of the present invention to provide an apparatus for covering the open muzzle of a firearm which allows the firearm to be safely discharged if it is fired while the cover is engaged to the muzzle.
It is another object of the present invention to provide a cover for the magazine well which may be easily removed with one finger whether the weapon is being used by a left-handed or right-handed person.
SUMMARY OF THE INVENTION
The above objects are satisfied by the present invention by providing a muzzle cover and a magazine well cover to be placed over the respective orifices of a weapon in order to prevent the entry of contaminants into the weapon.
The method of the present invention involves covering the open muzzle and open magazine well cover of a weapon with fast-action removable caps which snap onto the orifices. Then, when the weapon is ready to be used, the two caps can be quickly removed from the weapon and a normal magazine can be inserted into the magazine well. Alternatively, the cap to cover the muzzle may be one designed to be removed by actual firing of the weapon.
The apparatus of the present invention comprises separately and in combination a device for covering the muzzle of a weapon and a device for covering the magazine well.
First, the muzzle cover is a cap device that snaps over the muzzle to prevent the intrusion of sand, water or other debris from entering the weapon's barrel. For instance, on an M16A2, the muzzle cover snaps over the muzzle compensator. The cover is produced from low density polyethylene material. It is solid and is retained on the weapon by its compression fit. The cap can be installed by the user without tools by pressing it over the muzzle of the weapon. It can be removed by hand by pulling it directly off of the barrel, preferably by a ridge which extends outward around the rim of the cap which gives leverage so that the cap may be removed by pushing on the ridge with a thumb. In the heat of battle, it is important that the cover be removed as quickly as possible. Furthermore, it is possible that a soldier or other user of a weapon may forget to remove the muzzle cover. For both of these reasons, it is desirable to have a muzzle cover which can be safely removed by the firing of the weapon. Therefore, in the present invention, a muzzle cover is designed so that a projectile being fired will pass harmlessly through the cap and continue downrange without deflection, while the escaping gases will expand the cap and blow it clear of the weapon.
Second, the invention comprises a magazine well cover which is also made of low density polyethylene. The magazine well cover is designed to be compressed over the magazine well opening on the bottom of the magazine receiver. This cover comprises a cap which will provide a near air-tight fit over the well opening. The cap is designed with a ridge around its periphery which will permit the user to easily grab and remove the cap by pulling directly down on it. In addition, two large flat tab surfaces are located on the left and right front end of the cover near the trigger housing mechanism to permit the user to quickly detach the cover by pushing downward with his thumb. The flat surface has been provided on both sides of the cover to compliment the ambidextrous nature of weapons such as the M16A2 rifle.
These and other objects and advantages will appear from the following description with reference to the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top view of the muzzle cover of the present invention.
FIG. 2 is a cross section view of the muzzle cover of FIG. 1, taken along line 2--2 of FIG. 1.
FIG. 3 shows the muzzle cover of FIG. 2 installed on a rifle muzzle having a muzzle compensator.
FIG. 4 is a top view of the magazine well opening cover of the present invention.
FIG. 5 is a cross-sectional view of the magazine well opening cover of FIG. 4, taken along line 4--4 of FIG. 4.
FIG. 6 shows the magazine well opening cover of FIG. 5 located in place on the end of a magazine receiver.
DESCRIPTION OF PREFERRED EMBODIMENT
The preferred embodiment is now described with reference to the drawings, in which like numbers indicate like parts throughout the views.
FIGS. 1 and 2 show a muzzle cover, and more specifically, a muzzle cover designed for an M16A2 rifle muzzle. The muzzle cover 10 is a single piece of molded low density polyethylene or other plastics material. The cover 10 generally comprises a cylindrical portion 12 having a closed end 14 and an open end 16. A ridge portion 18 of the muzzle cover 10 extends outwardly from the cylindrical portion 12 at or near the open end of the cylinder 12 and is generally perpendicular to the axis of the cylinder. At or near the open end of the cylindrical portion 12 is a rib 20 located on the inside periphery of the cylindrical portion 12. The purpose of the rib 20 is to retain the muzzle cover 10 on the end of the muzzle by having the rib extend beyond a raised portion of the end of the muzzle, such as the muzzle compensator of the M16A2 rifle. Therefore, the length of the cylindrical portion 12 of the muzzle cover should be of sufficient length that the rib 20 will fit over a raised portion of the muzzle of the rifle to hold the cover 10 in place.
The end 14 of the muzzle cover 10 should be sufficiently thin so as to allow a projectile being discharged from the rifle to pass through the muzzle cover 10 with no significant deflection of the projectile. A thickness of approximately 4/100 of an inch has been found to be suitable for the muzzle cover. Also, in the preferred embodiment, the ridge 18 may be advantageously placed closer to the open end of the cylindrical portion 12 than the rib portion 20 such that the ridge portion 18 may provide a lever action to pull the adjacent portion of the rib 20 over a raised portion of the muzzle end of a weapon so that the muzzle cover may be easily and quickly removed from the weapon by manual means.
FIG. 3 shows the muzzle cover 10 installed on a rifle muzzle 60 having a muzzle compensator 62 which has openings 64 on the side which allow exhaust gases to exit through the openings 64 as well as the muzzle opening. FIG. 3 shows the end of a muzzle as it exists on an M16A2. The muzzle compensator 62 ends at a groove 46 into which the rib 20 of the muzzle cover 10 may fit. The inside diameter of the muzzle cover should be about 1/100 of an inch wider than the outside diameter of the muzzle compensator 62 so that the gases exiting from the muzzle when a round is fired will circulate around the inside of the cylinder 12 and expand and lift the muzzle cover 10 away from the muzzle, allowing it to be blown away harmlessly forward.
A magazine well opening cover of the present invention is shown in FIGS. 4, 5 and 6. The cover 30 shown in FIG. 4 is generally rectangular and comprises a cap portion 32 and a tab extension portion 34. The periphery of the cap portion 32 of the magazine well cover 30 has the same shape and dimensions as the outside of the open end 40 of the weapons' magazine receiver 42, as shown in FIG. 6 FIGS. 4-6 generally describe the size and shape of the invention as it would be used on an M16A2 rifle.
The cap portion 32 of the magazine well cover 30 comprises a flat closed end 36 to cover the magazine well opening with sides 38 extending generally perpendicularly away from the end 36 of sufficient width to maintain the cap in place around the opening 40 of the magazine receiver 42. A rib 39 is located at the open end of the cap portion 32 formed by the sides 38, on the inside periphery of the sides 38, to assist in holding the cap in place around a raised or flared portion 44 at the end of the magazine receiver 42.
An extension portion 34 of the magazine well cover 30 extends from at least one of the sides of the cap portion 32 of the cover 30. As shown in FIGS. 4 and 5, the extension portion 34 extends from one of the narrow sides of the cap portion 32 in generally the same plane as the end 36 of the cap portion 32. The extension portion comprises tab portions 35 to be used to remove the cover 30 from the magazine receiver 42. As with the muzzle cover, the tab portion 35 extends from the side 38 at the open end of the side 38 to provide a lever action to help easily pull the adjacent portion of the rib 39 away from the magazine receiver flared portion 44. This allows the magazine well cover 30 to be quickly removed by pushing on it with a thumb. Since rifles, such as the M16A2, generally are designed to allow use by either left-handed or right-handed persons, the magazine well cover 30 preferably has a tab portion on both the left side and the right side of the cover so that it may be removed easily from either side.
While this invention has been described in detail with particular reference to the preferred embodiment thereof, it will be understood that variations and modifications can be effected with the spirit and scope of the invention as previously described and as defined in the claims.
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A method and apparatus for protecting firearms from dirt and moisture are disclosed. Light-weight plastic covers are used to seal the openings of a firearm such as the muzzle opening or the magazine well opening. These protective covers are easily removable by simple manual operations. This muzzle cover can also be removed by actually firing the firearm, while imparting no significant deflection to the projectile.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application is a filing under 35 U.S.C. §371 and claims priority to international patent application number PCT/GB2005/002890 filed Jul. 22, 2005, published on Jan. 26, 2006, as WO 2006/008547, which claims priority to U.S. provisional patent application Nos. 60/590,814 filed Jul. 23, 2004, 60/645,915 filed Jan. 21, 2005 and 60/645,968 filed Jan. 21, 2005; the disclosures of which are incorporated herein by reference in their entireties.
GOVERNMENT SUPPORT
This invention was made with government support under GM052948 awarded by the NIH. The government has certain rights in the invention.
TECHNICAL FIELD
The present invention relates to novel non-destructive and dynamic means for determining the cell cycle position of living cells.
BACKGROUND OF THE INVENTION
Eukaryotic cell division proceeds through a highly regulated cell cycle comprising consecutive phases termed G1, S, G2 and M. The two transition phases, G1 and G2, are interspersed between the DNA synthesis (S) phase in which cellular DNA is replicated and the mitosis (M) phase in which each cell divides to form two daughter cells.
Disruption of the cell cycle or cell cycle control can result in cellular abnormalities or disease states such as cancer which arise from multiple genetic changes that transform growth-limited cells into highly invasive cells that are unresponsive to normal control of growth. Transition of normal cells into cancer cells arises though loss of correct function in DNA replication and DNA repair mechanisms. All dividing cells are subject to a number of control mechanisms, known as cell-cycle checkpoints, which maintain genomic integrity by arresting or inducing destruction of aberrant cells. Investigation of cell cycle progression and control is consequently of significant interest in designing anticancer drugs (Flatt P M and Pietenpol J A 2000 Drug Metab Rev 32(3-4):283-305; Buolamwini J K 2000 Current Pharmaceutical Design 6, 379-392).
Accurate determination of cell cycle status is a key requirement for investigation of cellular processes which affect the cell cycle or are dependent on cell cycle position. Such measurements are particularly vital in drug screening applications where:
a) drugs which directly or indirectly modify cell cycle progression are desired, for example as anti-cancer treatments. b) drugs are to be checked for unwanted effects on cell cycle progression. c) it is suspected that an agent is active or inactive towards cells in a particular phase of the cell cycle.
Traditionally cell cycle status for cell populations has been determined by flow cytometry using fluorescent dyes which stain the DNA content of cell nuclei (Barlogie B et al. Cancer Res. 1983 43(9):3982-97). Flow cytometry yields quantitative information on the DNA content of cells and hence allows determination of the relative numbers of cells in, or the proportion of cells in, the G1, S and G2+M phases of the cell cycle. However this analysis is a destructive non-dynamic process and requires serial sampling of a population to determine cell cycle status with time. Furthermore standard flow cytometry techniques examine only the total cell population in the sample and do not yield data on individual cells which precludes study of cell cycle status of different cell types that may be present within the sample under analysis. Flow cytometry is therefore suitable for examining the overall cell cycle distribution of cells within a population but cannot be used to monitor the precise cell cycle status of an individual cell over time.
Consequently what is needed to study the effects of agents with desired or undesired effects on the cell cycle is a method to precisely determine cell cycle status of a single living cell by a non-destructive method that allows the same cell to be repeatedly interrogated over time. Furthermore it would be advantageous for cell cycle position to be determined from a probe controlled directly by cell cycle control components, rather than indirectly through DNA content or other indirect markers of cell cycle position as described above.
A number of methods have been described which make use of certain components of the cell cycle control mechanisms to provide procedures which analyse or exploit cell proliferation status.
U.S. Pat. No. 6,048,693 describes a method for screening for compounds affecting cell cycle regulatory proteins wherein expression of a reporter gene is linked to control elements which are acted on by cyclins or other cell cycle control proteins. In this method temporal expression of a reporter gene product is driven in a cell cycle specific fashion and compounds acting on one or more cell cycle control components may increase or decrease expression levels. Since the assay system contains no elements which provide for the destruction of the reporter gene product nor for destruction of any signal arising from the reporter gene, the method can not yield information on the cell cycle position of any cells in the assay and reports only on general perturbations of cell cycle control mechanisms.
WO 03/031612 describes DNA reporter constructs and methods for determining the cell cycle position of living mammalian cells by means of cell cycle phase-specific expression control elements and destruction control elements. One embodiment uses well characterised elements of the cell cycle control protein Cyclin B1 to control the expression and degradation of a green fluorescent protein (GFP) molecule to report cellular transition through G2 and M phases of the cell cycle. Since this construct is under the control of the Cyclin B1 promoter, GFP expression is absent during G1 and S thus preventing analysis of cells in these phases of the cell cycle.
A human helicase B homolog has been reported and characterised ((Taneja et al J. Biol. Chem., (2002), 277, 40853-40861). The report demonstrates that helicase activity is needed during G1 to promote the G1/S transition.
Gu et al (Mol. Biol. Cell., (2004), 15, 3320-3332) have shown that a small C-terminal region of the helicase B gene termed the phosphorylation-dependent subcellular localization domain (PSLD) is phosphorylated by Cdk2/cyclin E and contains NLS and NES sequences. Gu et al (Mol. Biol. Cell., (2004), 15, 3320-3332) carried out studies on cells that had been transiently transfected with plasmid encoding an EGFP-βGal-PSLD fusion (beta-galactosidase (βGal) was included in the construct as an inert group to make the whole fusion protein similar in size to the complete helicase B) expressed from a CMV promoter. Cells in G1 exhibited EGFP signal predominantly in the nucleus, whilst cells in other phases of the cell cycle exhibited predominantly cytoplasmic EGFP signal. These researchers concluded that the PSLD was directing translocation of the βGal-EGFP reporter from the nucleus to the cytoplasm around the G1/S phase transition of the cell cycle.
None of the preceding methods which use components of the cell cycle control mechanism provides means for readily and accurately determining the cell cycle status of an individual cell or a population of cells throughout the entire cell cycle. Accordingly a method has been developed and is herein described which uses key components of the cell cycle regulatory machinery, in defined combinations, to drive dual independent cellular reporters to provide novel means of determining cell cycle status at all phases of the cell cycle in individual living cells.
SUMMARY OF THE INVENTION
According to the first aspect of the invention, there is provided a stable cell line expressing:
i) a first polypeptide construct comprising a first detectable live-cell reporter molecule linked to at least one cell cycle phase-dependent location control element, the location of which construct within a mammalian cell is indicative of the cell cycle position; and ii) a second polypeptide construct comprising a second detectable live cell reporter molecule linked to a destruction control element wherein said second reporter is detectable in a mammalian cell at a predetermined position in the cell cycle,
wherein said first and second reporter molecules are distinguishable from each other and the stable cell line can be used to determine the cell cycle position.
The present invention provides cell lines containing polypeptide constructs which exhibit cell cycle phase specific activation, translocation or destruction of detectable reporter molecules by direct linkage of reporter signals to temporal and spatial expression, localisation and destruction of cell cycle components. This greatly improves the precision of determination of cell cycle phase status and allows continuous monitoring of cell cycle progression in individual cells. Furthermore the inventors have discovered that these key control elements can be isolated and abstracted from functional elements of the cell cycle control mechanism to permit design of cell cycle phase reporters which are dynamically regulated and operate in concert with, but independently of, endogenous cell cycle control components and hence provide means for monitoring cell cycle status without influencing or interfering with the natural progression of the cell cycle.
Suitably, the cell cycle phase-dependent location control element is selected from the group of peptides consisting of Rag2, Chaf1B, Fen1, PPP1R2, helicase B, sgk, CDC6 or motifs therein such as the phosphorylation-dependent subcellular localization domain of the C-terminal special control region of helicase B (PSLD).
Suitably, the destruction control element comprises the Cyclin B1 D-box.
Suitably, the first and second live-cell reporter molecules are selected from the group consisting of fluorescent protein and enzyme reporter.
Preferably, said fluorescent protein is selected from the group consisting of Green Fluorescent Protein (GFP), Enhanced Green Fluorescent Protein (EGFP), Emerald and J-Red. Preferably, said enzyme reporter is halo-tag (Promega).
Preferably, the first reporter molecule is EGFP and the second reporter molecule is J-Red, or the first reporter molecule is J-Red and the second reporter molecule is EGFP. More preferably, the first reporter molecule is J-Red and the second reporter molecule is EGFP.
In one preferred embodiment of the invention the first polypeptide construct comprises the phosphorylation-dependent subcellular localization domain of the C-terminal spatial control region of helicase B (PSLD) coupled to a red fluorescent protein (RFP), and the second polypeptide construct comprises 171 amino acids of the amino terminus of cyclin B1 coupled to a green fluorescent protein (GFP) expressed under the control of the cyclin B1 promoter.
When expressed in a mammalian cell these constructs exhibit cell cycle specific expression and destruction of the GFP construct and translocation of the RFP construct, with the GFP construct paralleling the expression and degradation of endogenous cyclin B1, and the RFP construct paralleling the translocation of endogenous Helicase B. Hence measurement of both GFP and RFP fluorescence intensity and localisation permits identification of cells in G1, S, G2 and M phases of the cell cycle. Analysis of the fluorescence characteristics of each cell in a population with time consequently yields dynamic information on the cell cycle status of each cell.
In further aspects of the invention there are provided methods for analysing cell cycle distribution of cultured cells and determining the effects of test agents on cell cycle distribution. The term ‘test agent’ should be construed as a form of electromagnetic radiation or as a chemical entity. Preferably, the test agent is a chemical entity selected from the group consisting of drug, nucleic acid, hormone, protein and peptide. The test agent may be applied exogenously to the cell or may be a peptide or protein that is expressed in the cell under study.
Thus, in a second aspect of the present invention, there is provided a method for determining the cell cycle position of a mammalian cell, said method comprising:
a) culturing a stable cell line as hereinbefore described; and b) determining the cell cycle position by monitoring signals emitted by the first and second reporter molecules.
In a third aspect of the present invention, there is provided a method of determining the effect of a test agent on the cell cycle position of a mammalian cell, said method comprising:
a) culturing a stable cell line as hereinbefore described; and b) determining the cell cycle position by monitoring signals emitted by the first and second reporter molecules wherein a difference between the emitted signals measured in the absence and in the presence of said test agent is indicative of the effect of the test agent on the cell cycle position of the cell.
In a fourth aspect of the present invention, there is provided a method of determining the effect of a test agent on the cell cycle position of a mammalian cell, said method comprising:
a) culturing a stable cell line as hereinbefore described; b) determining the cell cycle position by monitoring signals emitted by the first and second reporter molecules; and c) comparing the emitted signals in the presence of the test agent with a known value for the emitted signals in the absence of the test agent;
wherein a difference between the emitted signals measured in the presence of the test agent and said known value in the absence of the test agent is indicative of the effect of the test agent on the cell cycle position of the cell.
In yet a further aspect of the present invention methods are provided for determining the cell cycle dependencies of cellular processes by means of monitoring cellular processes in cells reporting the cell cycle position.
Thus, according to the fifth aspect of the present invention, there is provided a method of determining the effect of the mammalian cell cycle on a cellular process monitored by a process reporter which is known to vary in response to a test agent, said method comprising:
a) culturing a stable cell line as hereinbefore described; b) determining the cell cycle position by monitoring signals emitted by the first and second reporter molecules; and c) monitoring the signals emitted by the process reporter wherein the process reporter is distinguishable from the first and second reporter molecules;
wherein the relationship between cell cycle position determined by step b) and the signal emitted by the process reporter is indicative of whether or not the cellular process is cell cycle dependent.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a vector map of pCORON1002-EGFP-C1-PSLD.
FIG. 2 shows vector maps of pCORON1022-JRed-C1-PSLD ( FIG. 2 a ) and pCORON1020-JRed-C1-PSLD ( FIG. 2 b ).
FIG. 3 presents images of U2OS cells expressing the cyclin B1-EGFP and the PSLD-J Red fluorescent proteins using an IN Cell Analyzer 1000 (GE Healthcare) imaging system. The cells are seen to be at varying stages of their cell cycle, as depicted by letters/numerals ‘S’, ‘G1’ and ‘G2’. The presence of the Hoechst dye is indicated by the blue fluorescence in FIG. 3 a , of expression of the G2/M Cyclin B1 green fluorescent protein reporter in FIG. 3 b and the expression of the G1/S PSLD red fluorescent protein reporter in FIG. 3 c.
DETAILED DESCRIPTION OF THE INVENTION
PSLD-RFP Construct
Full-length Human DNA helicase B (HDHB) cDNA was inserted as a BgIII/NotI fragment (Taneja et al., J. Biol. Chem., (2002) 277, 40853-40861) into the NotI site of the pEGFP-C1 vector (Clontech). PCR amplification of the 390 by PSLD region and introduction of 5′ NheI and 3′ SaII restriction enzyme sites to the PSLD fragment were used to sub-clone into the vector pCORON1002-EGFP-C1 (GE Healthcare). The resulting 6704 by DNA construct pCORON1002-EGFP-C1-PSLD ( FIG. 1 ), contains an ubiquitin C promoter, a bacterial ampicillin resistance gene and a mammalian neomycin resistance gene. Further modification of this vector was carried out using standard PCR and cloning techiques (Sambrook, J. et al (1989)) to replace the EGFP with the fluorescent protein J-Red (Evrogen), to convert the plasmid from the neomycin resistance to hygromycin resistance ( FIG. 2 a ) and to replace the ubiquitin C promoter with CMV IE/promoter ( FIG. 2 b ).
Dual Construct Stable Cell Line
A U2OS cell line stably expressing a Cyclin B1-EGFP cell cycle reporter (as described in WO03/031612 and supplied under product code 25-80-10 ‘G2M Cell Cycle Phase Marker’ from Amersham Biosciences UK Limited/GE Healthcare Biosciences) was cultured according to the supplier's instructions. Cells were transfected with plasmids ( FIGS. 2 a and 2 b ) encoding the PSLD-RFP fusion protein (SEQ ID NO: 1) using Fugene (Roche) according to the manufacturer's instructions. Cells were placed under hygromycin (125 μg/ml) and neomycin (500 μg/ml) selection, and surviving clones selected for further expansion.
Imaging of Stable Cell Line Expressing G1/S and G2/M Sensors
A stable U2OS cell line expressing Cyclin B1-EGFP and PSLD-J Red fluorescent fusion proteins was grown in 96 well plates in McCoys medium supplemented with 10% serum under standard tissue culture conditions. Cells were fixed in 2% paraformaldehyde, stained with Hoechst, and imaged using an IN Cell Analyzer 1000 (GE Healthcare) with appropriate excitation and emission filters for blue (Hoechst), green (Cyclin B1-EGFP) and red (PSLD-J Red) fluorescence.
EXAMPLES
Below, the present invention will be explained in more detail by way of examples, which however are not to be construed as limiting the present invention as defined by the appended claims. All references given below and elsewhere in the present specification are hereby included herein by reference.
Example 1
Images of the stable cell line cell line expressing Cyclin B1-EGFP and PSLD-J Red ( FIG. 3 ) show differential expression and localisation of the green and red fusion proteins between cells in different phases of the cell cycle. Determination of the presence or absence of green and red fluorescent fusion proteins in the cytoplasm and nucleus of each cell allowed designation of cell cycle position according to the following scheme:
G1
S
G2
M
Cytoplasm
Green
−
−
+
+
Red
−
+
+
+
Nucleus
Green
−
−
−
+
Red
+
−
−
+
Experimental details relating to the production of stable cell lines expressing a polypeptide construct comprising a first detectable live-cell reporter molecule linked to at least one cell cycle phase-dependent location control element, the location of which construct within a mammalian cell is indicative of the cell cycle position, have been described in Applicant's copending U.S. provisional patent application US60/645,968 entitled “Cell Cycle Phase Markers”, the disclosure of which is incorporated herein by reference in its entirety.
The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although a few exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims. Therefore, it is to be understood that the foregoing is illustrative of the present invention and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the appended claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.
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The present invention relates to non-destructive and dynamic means for determining the cell cycle position of living cells. The invention provides stable cell lines which can be used to determine the cell cycle position, together with methods for measuring the effect of a test agent on the cell cycle position.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation, under 35 U.S.C. § 120, of my copending international application PCT/DE02/03596, filed Sep. 24, 2002, which designated the United States; this application also claims the priority, under 35 U.S.C. § 119, of German patent application No. 101 47 172.6, filed Sep. 25, 2001; the prior applications are herewith incorporated by reference in their entirety.
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
[0002] The invention relates to a reducing agent pump for an exhaust-gas aftertreatment system of an internal combustion engine, that is, to a pump for delivering reducing agent in liquid phase to an exhaust-gas aftertreatment system of an internal combustion engine.
[0003] The levels of nitrogen oxide emissions from an internal combustion engine operating with excess air, in particular a diesel internal combustion engine, can be reduced with the aid of a so-called selective catalytic reduction (SCR), wherein atmospheric nitrogen (N 2 ) and water vapor (H 2 O) are formed. Reducing agents used are either gaseous ammonia (NH 3 ), ammonia in aqueous solution, or urea in aqueous solution. The urea serves as an ammonia carrier and is injected into the exhaust system upstream of a hydrolysis catalytic converter with the aid of a metering system. Then it is converted into ammonia by means of hydrolysis in the hydrolysis catalytic converter, and the ammonia then in turn reduces the nitrogen oxides in the actual SCR or deNOx catalytic converter.
[0004] The main components of a metering system of this type include a reducing agent tank, a pump, a pressure regulator, a pressure sensor, and a metering valve. The pump delivers the reducing agent stored in the reducing agent tank to the metering valve, by way of which the reducing agent is injected into the exhaust-gas stream upstream of the hydrolysis catalytic converter. The metering valve is driven with signals from a control device in such a manner that a defined, currently required quantity of reducing agent is supplied as a function of operating parameters of the internal combustion engine. See U.S. Pat. No. 6,082,102 and German patent DE 197 43 337 C1.
[0005] An advantage of the ammonia-releasing substances which are present in aqueous solutions, such as for example urea, is that in technical terms they are relatively simple to store, handle, deliver and meter. One drawback of these aqueous solutions is that there is a risk that they may freeze at certain temperatures, depending on the concentration of the dissolved substance.
[0006] 32% strength urea solution, as is typically used as reducing agent in SCR systems, has a freezing point of −11° C. Consequently, it is necessary to provide devices for heating the metering system in order to ensure that all the system components are able to function within a reasonable time of the system being started at ambient temperatures of below −11° C. and to prevent system components from freezing during operation.
[0007] One of the main components is the reducing agent pump. Since aqueous urea solution imposes high demands on the seals in the system, on account of its creep properties, in general only pumps without shaft bushings, i.e. only with static seals, are used. Diaphragm pumps as well as reciprocating piston pumps satisfy this condition. It is preferable to use electro-magnetically driven reciprocating piston pumps to meter aqueous urea solution as reducing agent for exhaust-gas aftertreatment in internal combustion engines.
[0008] One problem of these reciprocating piston pumps is that in the quiescent state of the pump piston, a liquid volume is in principle enclosed between the piston check valve (nonreturn valve) and the outlet check valve (nonreturn valve). This liquid volume is dependent on the design of the pump but is at least equal to the displacement of the pump piston. If the reducing agent in the pump outlet has already frozen at temperatures below the freezing point of the reducing agent, it is no longer possible to compensate for the increase in volume of the enclosed reducing agent. The piston check valve does not permit any pressure compensation in the direction of the reducing agent tank, and the pump is damaged by the resultant increase in pressure.
[0009] German published patent application DE 44 32 577 A1 describes a device for preventing frost damage to parts of an exhaust-gas purification system which operates in accordance with the selective catalytic reduction principle during inoperative periods and for allowing systems of this type to operate at temperatures below the freezing point of the reducing agent solution. For that purpose, the device has a thermally insulated storage tank for the reducing agent solution and a feedline which is connected to the tank and ends in an outlet opening for the liquid. A backwash valve, which can be acted upon by a pressurized gas, is provided in the feedline. The storage tank and the feedline can in this case be heated by way of an electrical heater which supplies a heat exchanger with heat.
[0010] German patent DE 36 10 882 C2 describes a double-acting piston pump for delivering liquid with or without solids, having multipart pistons which are fitted to the piston rod and have an inner and outer gasket on the circumference of the piston. A piston base with a stripper ring is arranged on the piston rod. Moreover, a biasing spring is positioned between the two gaskets. The multipart piston comprises a sleeve spring, which is arranged centrically with respect to the biasing spring and has an outer sleeve and an inner sleeve with an elastic element arranged between the two sleeves, the inner sleeve being in a fixed position around the piston rod part, while the outer sleeve together with the stripper ring forms an abutment for the outer gasket. An arrangement of this type provides a frostproof pump. After the delivery medium has been drained or extracted from the pump spaces, with residual medium remaining in the pump interior, the pump itself is not damaged even in the event of a sharp frost. The increase in volume which occurs through the formation of ice in the interior of the pump is compensated for by the expansion of the sleeve spring.
[0011] U.S. Pat. No. 6,526,746 B1 and German published patent application DE 101 29 592 A1 describe an on-board configuration for releasing reducing agent for the exhaust pipe of a motor vehicle provided with an internal combustion engine. The system has a nozzle for atomizing the reducing agent into the exhaust pipe, with a transfer pipe being connected to the nozzle for releasing reducing agent. There is a casing with an outlet, which is connected to the transfer tube opposite the nozzle. The casing has a front end which forms a mixing chamber, and a main body with inlets for the compressed air and reducing agent. An electrically operated fluid-dispensing pump with exposed coils is cooled by the air which is supplied to the casing through the compressed-air inlet, with the fluid-dispensing device having an inlet which is connected to the reducing-agent inlet of the casing.
SUMMARY OF THE INVENTION
[0012] It is accordingly an object of the invention to provide a reducing agent pump for an aftertreatment system of an internal combustion engine which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which ensures reliable operation of the exhaust-gas aftertreatment system even at temperatures below the freezing point of the reducing agent that is to be delivered by way of the pump.
[0013] With the foregoing and other objects in view there is provided, in accordance with the invention, a reducing agent pump for delivering liquid reducing agent to an exhaust-gas aftertreatment system of an internal combustion engine. The novel pump comprises:
[0014] a cylindrical pump body;
[0015] a coil carrier surrounding the pump body and serving to receive an electromagnet;
[0016] a piston disposed to execute an axial movement in the pump body when the electromagnetic is being energized;
[0017] a pump inlet part and a pump outlet part closing off the pump body at respective ends thereof, at least one of the pump inlet part and the pump outlet part forming a two-piece part having a first element and a closure element; and
[0018] a spring element disposed to bias the first element relative to the closure element and to allow a relative movement between the first element and the closure element when a pressure exceeds a spring force of the spring element.
[0019] In other words, the concept forming the basis of the invention is that the pump outlet part and/or the pump inlet part closing off the pump body at its ends is/are configured in two parts, with in each case part of the pump inlet part and/or of the pump outlet part being prestressed by means of a spring element with respect to the other part, so that in the event of a pressure which predetermines the spring force of the spring element being exceeded, a relative movement can be carried out between the two parts.
[0020] This has the advantage that an increase in the volume of the reducing agent which is present inside the pump body, caused by freezing, can be absorbed and in this way it is possible to prevent damage to the reducing agent pump.
[0021] In accordance with an added feature of the invention, at least one of the pump inlet part and the pump outlet part comprises a cylindrical base body forming the first element and projecting into the pump body, and the closure element.
[0022] In accordance with an additional feature of the invention, the base body is displaceably mounted in the pump body and the closure element is fixedly connected to the coil carrier.
[0023] In accordance with another feature of the invention, the spring element is braced between mutually facing end faces of the base body and the closure element, respectively.
[0024] In accordance with a further feature of the invention, the spring element is a cup spring, a spring disc, or a coil spring.
[0025] In accordance with again an added feature of the invention, the closure element is screwed to the coil carrier.
[0026] In accordance with again another feature of the invention, the base body is formed with a connection piece for receiving a reducing agent line.
[0027] In accordance with a concomitant feature of the invention, the base body has a periphery formed with a groove and a radial sealing element mounted in the groove, the sealing element establishing a seal in the event of an axial movement of the base body within the pump body.
[0028] Other features which are considered as characteristic for the invention are set forth in the appended claims.
[0029] Although the invention is illustrated and described herein as embodied in a reducing agent pump for an exhaust-gas aftertreatment system of an internal combustion engine, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
[0030] The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] [0031]FIG. 1 is a schematic diagram and block diagram illustrating an internal combustion engine with an associated exhaust-gas aftertreatment system wherein the reducing agent pump according to the invention is used; and
[0032] [0032]FIG. 2 is a diagrammatic view of a reducing agent pump according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is shown a highly simplified illustration, in the form of a block diagram, of an internal combustion engine which is operated with excess air, together with an associated exhaust-gas aftertreatment system. The figure illustrates only those parts which are necessary in order to gain an understanding of the invention. In particular, the fuel cycle is not illustrated. In this exemplary embodiment, the internal combustion engine is a diesel engine, and the reducing agent used for the aftertreatment of the exhaust gas is aqueous urea solution.
[0034] The air required for combustion is fed to the internal combustion engine 1 via an intake line 2 . An injection system, which may be configured, by way of example, as a high-pressure storage injection system (common rail system) with injection valves that inject fuel directly into the cylinders of the internal combustion engine 1 , is denoted by reference numeral 3 .
[0035] The exhaust gas from the internal combustion engine 1 flows via an exhaust pipe 4 to an exhaust-gas aftertreatment system 5 and, from the latter, via a non-illustrated muffler into the open air.
[0036] An engine control unit 6 for controlling the internal combustion engine 1 is connected to the internal combustion engine 1 via a data and control line 7 , which is only diagrammatically indicated in the figure. Signals from sensors (e.g. temperature sensors for intake air, charge air, coolant, load sensor, speed sensor) and signals for actuators (e.g. injection valves, control elements) are transmitted between the internal combustion engine 1 and the engine control unit 6 via the data and control line 7 .
[0037] The exhaust-gas aftertreatment system 5 includes a reduction catalytic converter 8 , which comprises a plurality of catalytic converter units that are connected in series and are not indicated in any more detail. In addition, an oxidation catalytic converter may be arranged upstream and/or downstream of the reduction catalytic converter 8 , although this is not shown. Furthermore, there is a metering control unit 9 , which is assigned to a reducing-agent storage tank 10 with an electrically actuable reducing agent pump 11 for delivering the reducing agent.
[0038] In the exemplary embodiment, the reducing agent is aqueous urea solution which is stored in the reducing-agent storage tank 10 . The latter has an electrical heating device 12 and sensors 13 , 14 which record the temperature of the urea solution and the level in the reducing-agent storage tank 10 . Moreover, the signals from a temperature sensor arranged upstream of the reduction catalytic converter 8 and from an exhaust-gas measurement pick-up, e.g. an NOx sensor, arranged downstream of the reduction catalytic converter 8 are transmitted to the metering control unit 9 .
[0039] The metering control unit 9 actuates an electromagnetic metering valve 15 , to which urea solution is fed on demand via a feedline 16 from the reducing-agent storage tank 10 with the aid of the reducing agent pump 11 . A pressure sensor 18 , which records the pressure in the metering system and emits a corresponding signal to the metering control unit 9 , is incorporated in the feedline 16 . The urea solution is injected into the exhaust pipe 4 by means of the metering valve 15 upstream of the reduction catalytic converter 8 .
[0040] When the internal combustion engine 1 is in operation, the S exhaust gas flows through the exhaust pipe 4 in the direction indicated by the arrow.
[0041] The metering control unit 9 is connected to the engine control unit 6 via an electrical bus system 17 so that they can exchange data. The operating parameters which are of relevance to the calculation of the quantity of urea solution to be metered, such as for example the engine speed, air mass, fuel mass, control displacement of an injection pump, exhaust-gas mass flow, operating temperature, charge air temperature, start of injection, etc., are transmitted to the metering control unit 9 via the bus system 17 .
[0042] Working on the basis of these parameters and the measured values for the exhaust-gas temperature and the NOx content, the metering control unit 9 calculates the quantity of urea solution to be injected and emits a corresponding electrical signal to the metering valve 15 via an electrical connecting line. The urea is hydrolyzed and intimately mixed as a result of being injected into the exhaust pipe 4 . The catalytic reduction of the NOx in the exhaust gas to form N 2 and H 2 O takes place in the catalytic converter units.
[0043] The metering valve 15 for introducing the urea solution into the exhaust pipe 4 largely corresponds to a standard low-pressure gasoline injection valve, which is secured releasibly, for example, in a valve-holding device which is fixedly connected to a wall of the exhaust pipe 4 .
[0044] [0044]FIG. 2 shows a sectional view through the reducing agent pump 11 for delivering liquid reducing agent. This reducing agent pump 11 is an electromagnetic reciprocating piston pump, often also referred to as a magnetic piston pump. It has a cylindrical pump body 111 and an electromagnetic 112 which is pushed over the pump body and has a coil winding. The coil winding is fitted to a coil carrier 113 . The pump body 111 comprises a tube 114 , which is thin-walled with respect to its diameter and is made from a material which is resistant to reducing agent, for example from special steel. A piston 115 which can be moved in a reciprocating manner through energization of the coil winding of the electromagnet 112 is located in the tube 114 .
[0045] At one of its free ends, the tube 114 is closed off by a pump inlet part 116 , which is of two-piece design, and at its other free end it is closed off by a pump outlet part 117 , which is likewise of two-piece design.
[0046] The pump inlet part 116 comprises a single-piece, cylindrical base body 118 , which projects into the tube 114 , is matched to the inner diameter of the tube 114 and, at its end which projects out of the tube 114 , has a cylindrical connection piece 119 , which is tapered with respect to the diameter of the base body 118 , and a cylindrical closure part or closure element 120 for fixing the base body 118 in the tube 114 . The connection piece or stub 119 is used for connection of a reducing agent line, in particular a hose connection leading to the reducing agent tank 10 (FIG. 1).
[0047] The closure element 120 has a central bore 121 for the connection piece 119 to pass through and, on its outer contour, a screw thread 122 which interacts with a mating screw thread 123 on a shoulder 124 of the coil carrier 113 . The shoulder 124 is designed as a ring which projects from the end side of the coil carrier 113 and the internal diameter of which is greater than the diameter of the tube 114 . The axial length of the shoulder 124 is in this case such that, after the base body 118 has been introduced into the tube 114 and a screw connection has been effected between the end side of the coil carrier 113 and that side of the closure element 120 which faces this end side, by means of the closure element or part 120 , a cavity is formed in the shape of a cylindrical chamber 125 . A spring element 126 is disposed in this chamber 125 , in such a manner that when the closure part 120 has been screwed into place, the base body 118 is fixed resiliently in the tube 114 . The spring element 126 illustrated in FIG. 2 is a cup spring. However, it is also possible to use other spring elements, such as for example coil springs, spring discs, or the like.
[0048] On its circumference, the base body 118 has a radial groove, not indicated in more detail, for receiving a radial sealing element 127 . The radial sealing element 127 used is preferably what is known as an O-ring seal.
[0049] The base body 118 and the connection piece which is formed integrally thereon have a continuous, central passage 128 , wherein reducing agent is passed to the piston 115 . The piston likewise has a central passage 129 , within which, on the side facing the pump inlet part 116 , a chamber 135 , wherein a piston check valve or non-return valve 130 is arranged, is formed. This piston check valve 130 , in the case illustrated, comprises, in the customary way, a ball and a spring element acting on the ball, so that the passage 129 can be closed as required.
[0050] The pump outlet part 117 is constructed in substantially the same way as the pump inlet part 116 , and consequently only the differences will be dealt with in this context. The cylindrical base body 136 of the pump outlet part 117 has a chamber 131 , wherein an outlet check valve 132 is arranged, as part of its central passage 128 , on the side facing the piston 115 . This outlet check valve 132 , in the case illustrated, comprises, in the customary way, a ball and a spring element acting on the ball, so that the passage 128 can be closed as required.
[0051] The connection piece 133 which is formed integrally at the free end of the base body of the pump outlet part 117 is used for connection of a reducing agent line, in particular a hose connection, which leads directly or indirectly to the metering valve 15 (FIG. 1).
[0052] A spring element 134 , which biases the piston 115 towards the pump inlet part 116 , is provided in the space in the tube 114 which is delimited by the end face of the piston 115 which faces the pump outlet part 117 and the end face of the base body of the pump outlet part 117 which faces the piston 115 .
[0053] A configuration of this nature safely protects the reciprocating piston pump 11 from being destroyed as a result of an excessively high pressure being produced in the event of the reducing agent freezing, with an associated increase in its volume. At a defined maximum pressure, the base body 118 is pressed outward, counter to the spring force of the spring element 126 . The spring element 126 provides a defined force which corresponds to the product of the maximum pressure—which is determined for example by tests—and the cross section of the tube 114 . As a result, the increase in volume of the reducing agent inside the reciprocating piston pump 11 can be absorbed by the axial displacement of the base body 118 . The radial sealing between base body 118 and tube 114 by means of an O-ring seal permits this axial displacement.
[0054] An exemplary embodiment wherein pump inlet and pump outlet are mounted resiliently has been explained with reference to FIG. 2. However, it is also possible for just one side of the pump, wherein case preferably the pump inlet, to be mounted resiliently. The pump outlet part 117 could then be a single-piece design, i.e. base body and closure part are screwed to the coil carrier as a single part.
[0055] Because of the working principle of the reciprocating piston pump (piston stroke movement, not reliably self-priming), the pump is arranged at a lower level than the reducing agent tank (FIG. 1).
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A reducing agent pump has a pump inlet part and a pump outlet part closing off the pump body at its ends. One or both of the inlet and outlet parts is of two-part construction, with a closure element and another element. The two elements are prestressed relative to one another with a spring element, so that in the event of a pressure which exceeds the spring force of the spring element, a relative movement can be carried out between the two elements of the two-part member. This makes it possible to absorb an increase in the volume of the reducing agent inside the pump body caused by freezing and therefore to prevent damage to the reducing agent pump.
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BACKGROUND OF THE INVENTION
The present invention relates generally to electrolytic flow cells, and more particularly to electrolytic cells that generate sodium hypochlorite from brine or seawater.
Prior art electrolytic flow cells have a plurality of parallel electrodes that are spaced apart along their outer edges and sealed along their perimeters to form an electrode stack. Electrolyte is admitted through an inlet at the base of the electrode stack and flows in the space between successive adjacent electrodes to an outlet at the top of the electrode stack. The electrolyte passes from one space between electrodes in the electrode stack to the next adjacent space between electrodes through apertures in each electrode. The apertures are horizontally displaced between adjacent electrodes to maximize the length of the flow path over which electrolysis takes place.
The outermost electrodes in the stack are monopolar while the intermediate electrodes are bipolar. Electrical power can then be applied to the electrode stack via electrical connections to the outer monopolar electrodes and this creates an anodic and a cathodic surface on each intermediate bipolar electrode. This causes electrolysis to occur as the electrolyte passes through the cell.
However, these electrolytic cells of the prior art suffer from the disadvantage that the voltage applied to the electrode stack is limited to a threshold value where the material(s) comprising the electrodes themselves begin to undergo electrolysis, limiting the efficiency of the electrolytic cell. Furthermore, passing the electrolyte between a single stack of electrodes results in an electrically charged electrolyte effluent. This electrically charged effluent can present a safety hazard if the electrolyte leaks and contacts a worker. Further, since the effluent is electrically charged, instrumentation valves and associated pipework in the effluent stream before and after the electrolytic cell must be lined or enclosed in or made of a plastic material and sealed against the charge, to prevent accidental contact with or induced corrosion of metallic parts that are in contact with ground potential, thereby increasing the complexity and cost of the cell's associated instrumentation pipework and fittings. The effects of stray current corrosion on the inlet pipework and instruments can be greater than on the outlet as the cell's positive power connection, i.e., the highest potential, is at the inlet to the cell.
SUMMARY OF THE INVENTION
The present invention overcomes these problems by providing an electrolytic cell with two or more electrode stacks, arranged back-to-back in flow path series. As used herein, the phrase "back-to-back" refers to the fact that two or more electrode stacks are arranged so that effluent leaves one stack at a cathodic terminal and enters the next stack at a cathodic terminal, or leaves one stack and enters the next stack at an anodic terminal. This has the effect of both increasing the area over which electrolysis can occur and, by ensuring the adjacent electrode stack has opposite polarity, reducing or entirely neutralizing the electrical charge in the electrolyte exiting the cell. This minimizes or eliminates the safety risk in the event of a leak at the discharge of the cell and significantly simplifies requirements placed on instrumentation, such as flow sensors, in the effluent stream. In an electrolytic cell of the present invention, standard, unlined instrumentation pipework and fittings can be used.
According to a preferred embodiment of the present invention the electrode stacks are constructed to fit and seal together in an inert, insulated housing to provide a simple and safe electrolytic cell that is both flexible to use and easy to maintain.
The electrodes in each stack may take the form of circular plates of which at least one face is treated with a noble metal or a mixture of noble metals. Alternatively, the electrodes may also be made of ceramic
The present invention may also include a stack of copper electrodes that are powered at a lower voltage (and current) just before the discharge from the cell. The electrodes coated with a noble metal or made of ceramic produce hypochlorous acid ions and the copper electrodes produce cuprous or cupric ions. The copper electrodes are gradually eroded or "sacrificed", combined with the hypochlorous acid ions, to produce a synergistic anti-foulant solution, with a significantly lower consumption of copper than prior art units.
The electrodes of a stack may be spaced apart by a spacer along the outer edge of each electrode and be sealed against the wall of the housing by an O-ring positioned along the outer circumferential edge of the electrode. As a further alternative, the spacer and seal can be combined into a U-shaped unit that receives the outer edge of each electrode in the well of the U. This U-shaped unit combines the function of sealing the edge of the electrode against the enclosing housing and spacing electrode plates apart. This structure decreases the number of parts to be assembled thereby simplifying assembly and eliminates the possibility of leakage between spacer and O-ring.
Electrical power is applied to each stack by means of connections to the monopolar electrodes in each electrode stack. The connections are arranged so that alternate electrode stacks have opposite polarities, so that in the case of the electrolyte cell with only two electrode stacks, the electrolyte flows from the cathode to the anode then anode to cathode or vice versa. In a preferred embodiment, power is supplied at a center connection between the electrode stacks.
This arrangement provides the additional benefit of sufficiently high flow rate of the electrolyte so that the electrodes are not fouled by the deposition of electrolysis byproduct salts. The electrode stacks are preferably arranged in a vertical orientation to ensure that gas byproducts are carried along with the electrolyte and evacuated from the cell. Further, since the cell housing is formed of a non-conductive, inert material and is insulated from the electrodes, the cell can be used in areas requiring enhanced safety equipment. Also, with each adjacent electrode stack independently powered from its own electrical connection, failure of one stack does not disable the entire cell since other stacks remain powered and continue to function.
These and other advantages of the present invention will be readily apparent to those of skill in the art from the following description when read in conjunction with the following drawing figures.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
The invention will now be further described with reference to the accompanying drawings:
FIG. 1 depicts a sectional view of an electrolytic cell;
FIG. 2 depicts a sectional view through part of the electrolytic cell of an alternative embodiment of the invention in which adjacent electrode stacks are powered from one electrical conductor;
FIG. 3 depicts a partial section view through one electrode stack; and
FIGS. 4A and 4B depict cross sections of electrode seals of the preferred embodiments.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 depicts an electrolytic cell 10 of the present invention. This electrolytic cell 10 comprises two electrode stacks 12, arranged so that their electrolytic flow paths are in series. That is, electrolyte or brine to be electrolyzed flows in an intake 24, through the electrode stacks, and out at discharge 26. The electrolyte flows from the intake 24 to a first stack 36 through a conduit 38, from the first stack to a second stack 40 through a conduit 42, and to the discharge 26 through a conduit 44.
Each electrode stack 12 is made up of a plurality of parallel electrodes 14, 16 that are kept a fixed distance apart by spacers/seals 18 and sealed along their perimeters by O-rings 20, as shown in greater detail in FIGS. 4A and 4B. As shown in FIG. 4B, the spacers/seals 18 act as the primary seal and the O-rings 20 act as the secondary seal. In a preferred embodiment, spacers 18 and O-rings 20 are combined to form a single U-shaped seal that receives the outer edge of the electrode in the well of the U, as shown in FIG. 4A. The outermost electrodes are monopolar electrodes 14, while the intermediate electrodes are bipolar electrodes 16. In a preferred embodiment, as shown in FIG. 1, the intrastack spacing between electrodes 14, 16 is substantially equal.
External electrical power is applied to each electrode stack 12 in the electrolytic cell 10 via electrical connections 22 to the outer monopolar electrodes 14. In an alternative embodiment shown in FIG. 2, adjacent electrode stacks 12 share a common electrical connection 22. One polarity of electrical power energizes monopolar electrodes 14 through the common electrical connection 22 and conductor 46. A conduit 48 directs electrolyte from a lower stack 52 to a higher stack 54.
The arrangement of electrical connections shown in FIGS. 1 and 2 may be referred to as "center powered." That is, power is provided by connection 22 to the "center" of the cell, i.e., between the electrode stacks 12. The electrical circuit is completed by connections 50 (not shown in FIG. 2) which return to the power source. The connections 22 conventionally have a positive pole and the connections 50 have a negative pole. Having an independent conductor for each stack provides redundancy in that failure of one connection does not disable the entire cell, while providing power to both stacks from a single conductor eliminates one conductor and reduces the overall cost of the cell. In a preferred embodiment, the housing 32, FIG. 2, is made by an injection molding process and is made of polypropylene or other appropriate moldable material. In this embodiment, the electrodes are permanently molded into the housing. Alternatively, the housing can be machined from a block of an insulating material such as polypropylene.
The application of external electrical power to the electrolytic cell 10 creates an anodic and a cathodic surface on each bipolar electrode 16.
As shown in FIG. 2, each electrode 14, 16 is provided with an aperture 28 at one side and the electrodes 14, 16 are arranged so that each aperture 28 is displaced from the aperture in each adjacent electrode 14, 16, preferably by 180 degrees. This configuration provides a series flow path. That is, electrolyte must pass through each space between electrodes from inlet to discharge, providing for a highly turbulent electrolyte flow path.
Electrolyte 30 passes into the electrolytic cell 10 through an inlet or intake 24 and then through the spaces between adjacent electrodes 14, 16 in each electrode stack 12 in turn. Electrolysis is driven by the application of external electrical current to the electrolytic cell 10. The electrolyte 30 containing the product of the electrolysis passes out of the cell through an outlet or discharge 26.
As shown in FIG. 1, the spacing between electrode stacks 12 is substantially greater than the intrastack electrode spacing.
The provision of multiple electrode stacks 12 increases the effective area of the electrodes over which electrolysis occurs and reduces or entirely neutralizes the net electrical charge in the electrolyte exiting the electrolytic cell.
The electrodes 14, 16 in each electrode stack 12 are preferably made of or coated with a noble metal or a mixture of noble metals. Alternatively, the electrodes may be made of ceramic. Titanium may be used as the major structural material (i.e., the "substrate" or the "carrier metal") of the electrodes 14, 16. The nobel metal greatly enhances electrolysis by conducting electrical current from the electrode into the electrolyte. Using titanium alone, without the noble metal coating, results in very inefficient electrolysis.
As just mentioned, the electrodes 14, 16 may be made of ceramic, without the need for a coating of a noble metal. Ceramic electrodes, although not as efficient as coated titanium electrodes, are sufficiently efficient for certain applications and provide a distinct advantage in being able to handle electrical power (the electric charge) in either polarity. A titanium substrate with one surface coated with a noble metal (such as ruthenium) provides a bipolar electrode. The coated surface becomes anodic and the uncoated surface is cathodic. Reversing the charge across a bipolar electrode rapidly destroys the substrate. However, this is not true of ceramic electrodes. So, ceramic electrodes cannot be inadvertently installed upside down.
Having the ability to reverse the polarity across a ceramic electrode provides another benefit. Production of hypochlorite from brine or seawater, because of high concentrations of magnesium and calcium, hydroxide salts tend to precipitate out and coat the electrode surfaces. Conventionally, minimizing precipitation of salts is accomplished by ensuring a minimum flow velocity of the electrolyte, such as for example 0.75 meters/sec. Because the electrodes are circular plates, flow rate across the plate from inlet to outlet aperture varies greatly, from about 0.8 meters/sec. at the inlet and outlet to about 1.2 meters/sec. at the center of the plate. These values will, of course, vary with plate size, the gap between electrodes, and the overall geometry of the cell. In the present invention using ceramic electrodes, reversing the electrical charge on the electrodes causes the precipitate hydroxide salts to be released into the electrolyte and carried away to the effluent.
A solution of copper ions has also been used as an anti-foulant. In the present invention, a stack of sacrificial copper plates may be included to provide copper ions to the solution. The stack of copper plates are preferably arranged after the electrodes that produce the hypochlorous acid ions. Also, the copper stack should be easily accessible so that, when the copper plates are expended, they can be easily replaced. It is suggested that the copper/hypochlorite combination is far more effective than hypochlorite alone.
In a preferred embodiment the plates of the electrode stack 12 are constructed to fit and seal together in an inert, insulated housing 32, to provide a safe electrolyte cell 10 that is both flexible to use and easy to maintain. The structural arrangement of the present invention provides the additional advantage that gaseous products of the electrolysis, particularly hydrogen, become entrained in the electrolyte and are carried out with the effluent. It has been found in some prior art electrolytic cells that hydrogen can migrate from operating cells to idle cells, and can present an explosion risk. In the vertical arrangement of the present invention, electrolysis gases are free to rise within the cell and are carried out of the discharge.
The present invention provides the additional advantage of being adaptable for use aboard ship as a complete assembly in sea chests (sea inlet water boxes). The center-powered, insulated design of this invention provides this advantage. Thus, no discharge pipework is required to transfer hypochlorite to the sea boxes as required in the prior art. The prior art normally requires special pipework that is resistant to the hypochlorite (pipework which often becomes blocked with hydroxides). The cell of the present invention can be installed in local machinery compartments without the need for pipework to penetrated water tight bulkheads. A central control unit may provide power to each cell (it is known in the art that penetrating bulkhead with power cables through stuffing tubes is far less critical than penetrating with pipes). Alternatively, local power transistor or thyristor/triac control units may be used for each cell. Such a cell would use thin (2 mm thick) titanium plates injection molded into the plastic body and coated with a precious metal. When the precious metal is expended, the cell is removed and replaced with a new one.
The present invention has been described in relation to preferred embodiments. However, those of skill in the art will recognize changes and modifications to the preferred embodiments that fall within the scope and spirit of the invention.
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An electrolysis cell provides a plurality of electrode stacks arranged electrically and mechanically back-to-back in a vertical orientation to develop an electrically neutral effluent. The electrode stacks comprise a plurality of electrode plates that seal against an inert housing by seals with a U-shaped cross-section. The cell is fully insulated and provides a series electrolyte flow path.
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FIELD OF THE INVENTION
This invention relates to activator compositions, particularly well suited for accelerating the hardening of cyanoacrylate adhesives. The invention also relates to novel mixtures of chemical compounds and to the use of the activator compositions and the novel mixtures for the accelerated hardening of cyanoacrylate adhesives. The invention further relates to a process for the accelerated bonding of substrates using cyanoacrylate adhesives.
BRIEF DESCRIPTION OF RELATED TECHNOLOGY
Adhesive compositions based upon cyanoacrylate esters are well known and have found extensive use, because of their rapid cure speed, excellent long-term bond strength, and applicability to a wide variety of substrates. They generally harden after only a few seconds, after which the joined parts exhibit at least a certain degree of initial strength.
It is known that certain cyanoacrylate (CA) adhesives typically harden by an anionic polymerisation reaction. If the adhesive is conventionally applied in a relatively thick layer in the joint gap or relatively large amounts of adhesive are applied so that relatively large drops of adhesive protrude from between the parts to be joined, rapid hardening throughout the adhesive may rarely be achieved, i.e. cure-through-gap or cure-through-volume (CTV) performance may be unsatisfactory.
With certain substrates, particularly substrates having acidic surfaces, such as wood or paper, the polymerisation reaction may be retarded, oftentimes to an unmanageable extent. Moreover, unless the adhesive is gelled or rendered thixotropic by appropriate additives to confer such properties, the wood or paper substrates, due to their porosity, tend to draw the adhesive out of the joint gap by capillary action before hardening has taken place in the gap.
Heretofore efforts have been made to accelerate the polymerisation of such CA adhesives by means of certain additives. Addition of accelerators directly to the adhesive formulation is possible to only a very limited extent, however, since substances having a basic or nucleophilic action, which would normally bring about a pronounced acceleration of the polymerisation of the cyanoacrylate adhesive, are generally used at the expense of the storage stability of such formulations.
Addition of such accelerators shortly before application of the adhesive results in virtually a two-component system. However, such method has the disadvantage that the working life is limited after the activator has been mixed in. In addition, with the small amounts of activator that are required, the necessary accuracy of metering and homogeneity of mixing are difficult to achieve. Moreover, use of such a two-component system is often seen as cumbersome to the end user, and sometimes only modestly improves the intended result.
Activators are also used in the form of a dilute solution which is either applied beforehand onto a substrate or part which is to be bonded, and/or is applied onto the adhesive where it is still liquid after the substrates have been joined. The solvents used for such dilute solutions of activators are generally low-boiling organic solvents, so that they may be readily evaporated, leaving the activator on the substrate/part or the adhesive.
Japanese Patent Application No. JP-A-62 022 877 proposes the use of solutions of lower fatty amines, aromatic amines, dimethylamine and the like. Japanese Patent Application No. JP-A-03 207 778 proposes the use of solutions of aliphatic, alicyclic and, especially, tertiary aromatic amines; particular examples which are mentioned are N,N-dimethylbenzylamine, N-methylmorpholine and N,N-diethyltoluidine.
Japanese Patent Application No. 59-66471 discloses a hardening accelerator for use with cyanoacrylate adhesives comprising an amine compound, with a boiling point of between 50° C. and 250° C., together with a deodorizer and a solvent. Examples of suitable amines are triethyl amine, diethyl amine, butyl amine, isopropyl amine, tributyl amine, N,N-dimethyl aniline, N,N-diethyl aniline, N,N-dimethyl-p-toluidine, N,N-dimethyl-m-toluidine N,N-dimethyl-o-toluidine, dimethyl benzyl amine, pyridine, picoline, vinyl pyridine, ethanolamine, propanolamine and ethylene diamine.
U.S. Pat. No. 3,260,637 of von Bramer discloses the use of a range of organic amines (excluding primary amines) as accelerators for cyanoacrylate adhesives, particularly for use on metallic and non-metallic substrates.
N,N-dimethyl-p-toluidine has been widely used as an accelerator for the accelerated hardening of cyanoacrylate adhesives. A crucial disadvantage of the use of that substance is the short duration of the surface activation, which does not permit long waiting times between application of the accelerator solution beforehand to the substrates to be bonded and the subsequent bonding process. In addition, the use of N,N-dimethyl-p-toluidine in some countries oftentimes involves rigorous regulatory labelling requirements.
Basicity of an accelerator substance is not a sufficient criterion for identifying solutions which are acceptable in practice in terms of application technology. Many substances, such as alkylamines, 1,2-di-(4-pyridyl-ethane), 4,4′-dipyridyl disulfide, 3-(3-hydroxypropyl)pyridine, 1,2-bis(diphenylphosphino)-ethane, pyridazine, methylpyridazine or 4,4′-dipyridyl, are so basic or nucleophilic that spontaneous superficial hardening takes place at the adhesive interface (shock hardening) before the activator is able to initiate polymerisation throughout the liquid adhesive layer by convection and diffusion. The result is that an often cloudy polymerisation occurs at the surface only. With other compounds, such as oxazoles, the basicity is evidently too low, and the hardening is often too slow for practical purposes.
German Patent DE-A-22 61 261 proposes accelerator substances containing the structural element —N═C—S—, including 2,4-dimethylthiazole. However, that compound has a very high volatility, so that activator solutions based thereon are unsuitable for application beforehand since the active ingredient also evaporates off with the solvent.
It is desired to find new activator compositions for use with cyanoacrylate adhesives, which activator compositions have a pronounced accelerating action and low volatility, so that application beforehand is also possible. It is also desired to find activators which are subject to regulatory labelling requirements less rigorous than is N,N-dimethyl-p-toluidine currently.
European Patent Specification No. 0 271 675 A2 of Three Bond Co. Ltd. describes a primer for CA resin compositions for use in bonding non-polar or highly crystallized resins such as polyolefins, polyethyleneterephthalates, nylons, fluorine-containing resins, soft PVC films etc. The primer comprises (A) a compound selected from the group consisting of benzene ring compounds having aldehyde group and nitrogen or oxygen atom-containing heterocyclic compounds having aldehyde group, and (B) an organic amine compound. Nitrogen-atom containing heterocyclic compounds having aldehyde group in the component (A) include 2-pyridine carboxylaldehyde, 2,6-pyridine carboxylaldehyde and pyrrole 2-carboxylaldehyde. The specification states that in bonding non-polar or highly crystallized resins using a CA adhesive the primer instantaneously exhibits a high bonding strength at ambient temperature by a simple procedure which comprises applying such primer onto a surface of one of the resins, applying the CA adhesive onto a surface of the other resin and bringing both the surfaces into contact with each other. The Three Bond specification is directed to priming the surfaces of substrates which are difficult to bond. As described, the surfaces of the two substrates are brought into contact with one another (i.e. with “zero gap”) and a high bonding strength is achieved instantaneously. The Three Bond specification is not concerned with an activator which is able to initiate polymerisation throughout a layer of adhesive (e.g. in a joint gap) by convection and diffusion without spontaneous superficial hardening taking place at the adhesive/substrate interface. In other words, the Three Bond specification is not directed to good CTV performance. A good CTV initiator should be a sufficiently slow initiator to allow effective initial mixing of the activator through the adhesive prior to polymerisation.
British Patent Specification No. 1 230 560 of International Chemical Company Limited (ICC) describes CA adhesive compositions containing certain substituted heterocyclic compounds as accelerators. The compositions may be presented in a two-part form, the first part comprising the CA adhesive and the second part comprising at least one of the substituted heterocyclic compounds, preferably in solution in an organic solvent. In the compositions in which the heterocyclic compound is an iminoethylene-substituted triazine or pyrimido-pyrimidine, the heterocyclic compound is invariably present in one part of a two-part composition because iminoethylene-substituted triazines and pyrimido-yprimidines accelerate the polymerisation so rapidly they must be kept apart from the CA composition before use. In example 1 of the ICC specification triallylcyanurate as accelerator is mixed with the CA monomer and there is no suggestion that it or other accelerators (apart from the iminoethylene-substituted triazines and pyrimido-pyrimidines) need to be presented in a two-part form. In example 2, triethylanemelamine as a 1% solution in acetone is used as a primer on two steel surfaces, after which the monomer-containing composition is applied onto the primed surfaces and the surfaces are placed in mutual contact (i.e. with “zero gap”). An effective adhesive bond is obtained. However the ICC Specification, like the Three Bond Specification discussed above, is not concerned with an activator which is able to initiate polymerisation throughout a layer of adhesive (e.g. in a joint gap).
Japanese Patent Abstract Publication No. 62018485 of Alpha Giken KK also describes a primer for a CA adhesive and is not concerned with an activator for good CTV performance.
Notwithstanding the state-of-the-art, it would be desirable to provide further activator substances and combinations of activator substances with different properties from the activator substances used up to now. It is particularly desirable to use a mixture of activators in order to obtain a combination of properties, some at least of which would not be expected.
Activator solutions are often applied by spraying. However there is a demand for activator solutions which can be applied in excess volumes (e.g. as drops) onto an adhesive already present on a substrate (e.g. in the form of a bead or fillet).
Aliphatic hydrocarbons such as heptane are often used as the solvent for CA activators. However if the activator solution is applied onto a bead or fillet of CA adhesive which is already on a substrate (“post-application”), particularly if the solution is applied in excess volumes, a white “halo” may be formed on the substrate around the adhesive bead in the course of curing. Although the present invention is not limited by any theory, it is thought that the solvent heptane, which is substantially insoluble in the CA adhesive composition, dissolves small amounts of CA monomer and that some of the heptane phase (i.e. the activator solution with traces of CA monomer dissolved therein) runs off the adhesive bead onto the substrate. The traces of CA monomer then polymerise, and after evaporation of the solvent a thin layer of whitish amorphous material is left on the substrate around the adhesive bead, creating a “halo”. This is visually unattractive and is undesirable, particularly when the substrate is of a dark colour, such as black or dark shades of colours such as blue, red, brown or green, as well as transparent substrates like glass or polycarbonate, on or through which a whitish layer would be clearly visible.
While it may be possible to use a solvent which is miscible with the CA adhesive composition, so that the solvent would mix with the adhesive, a miscible solvent would likely make the adhesive composition undesirably soft and bulky. In addition the solvent in the adhesive composition would likely take a longer time to evaporate than n-heptane which remains as a separate phase. Miscible solvents such as acetone, ethyl acetate or acetylacetone also have a stronger odour than n-heptane, and they would be unappealing to the end user. If one or both substrates is of plastics materials, a solvent which is miscible in the adhesive composition (such as acetone, toluene etc.) would also likely attack the plastics material.
One aspect of the invention according to the present application reduces the problem of the “halo” effect and provides activator solutions with different properties from the activator solutions used to date.
SUMMARY OF THE INVENTION
According to one aspect, the present invention provides a composition comprising a mixture of:
(A) a member selected from the group consisting of:
aromatic heterocyclic compounds having at least one N hetero atom in the ring(s) and substituted on the ring(s) with at least one electron-withdrawing group which decreases the base strength of the substituted compound compared to the corresponding unsubstituted compound,
N,N-dimethyl-p-toluidine,
and mixtures of any of the foregoing, with
(B) an organic compound containing the structural element, —N═C—S—S—.
According to another aspect, the present invention provides a composition comprising a mixture of:
(A) a member selected from the group consisting of:
aromatic heterocyclic compounds having at least one N hetero atom in the ring(s) and substituted on the ring(s) with at least one substituent selected from the group consisting of halo, CN, CF 3 , COOR, COR 4 , OR, SR, CONR 1 R 2 , NO 2 , SOR, SO 2 R 3 , SO 3 R 3 , PO(OR 3 ) 2 and optionally substituted C 6 -C 20 aryl, wherein R, R 1 , R 2 and R 4 (which may be the same or different) are H, optionally substituted C 1 -C 10 alkyl, or optionally substituted C 6 -C 20 aryl, and R 3 is optionally substituted C 1 -C 10 alkyl, or optionally substituted C 6 -C 20 aryl, N,N-dimethyl-p-toluidine,
and mixtures of any of the foregoing, with
(B) an organic compound containing the structural element, —N═C—S—S—.
According to a special feature, the present invention provides an activator composition for the accelerated hardening of cyanoacrylate adhesives, wherein the activator comprises a mixture of an aromatic heterocyclic compound as described above and an organic compound having the structural element, —N═C—S—S—. According to a further feature, the present invention provides an activator composition for the accelerated hardening of cyanoacrylate adhesives, wherein the activator comprises a mixture of a 3,5-dihalopyridine and an organic compound having the structural element, —N═C—S—S—, more particularly the structural element, —N═C—S—S—C═N—, more especially —N═C—S—S—C═N— wherein the N═C and C═N double bonds are parts of aromatic heterocyclic rings.
According to a further aspect, the present invention provides an activator composition for the accelerated hardening of a cyanoacrylate adhesive throughout the adhesive, wherein the activator comprises a member selected from the group consisting of:
aromatic heterocyclic compounds having at least one N hetero atom in the ring(s) and substituted on the ring(s)with at least one electron-withdrawing group which decreases the base strength of the substituted compound compared to the corresponding unsubstituted compound,
mixtures of any of the said aromatic heterocyclic compounds with each other, and/or with N,N-dimethyl-p-toluidine,
and mixtures of any of the said aromatic heterocyclic compounds and/or N,N-dimethyl-p-toluidine with an organic compound containing the structural element, —N═C—S—S—.
This aspect of the invention is particularly directed to good CTV performance, in particular accelerated hardening throughout the adhesive, in drops of adhesive or relatively large layers of adhesive in a joint gap which is larger than the “zero gap” achieved when two substrate surfaces are in contact. In general a gap having a greater width than 10 microns is of interest. The depth of the adhesive drop or layer perpendicular to the substrate surface is suitably in the range 0.5 mm-2 mm, particularly 0.75 mm-1.25 mm.
In the said organic compound containing the structural element —N═C—S—S—, the N═C double bond may optionally be part of an aromatic system, which may suitably be monocyclic, bicyclic or tricyclic. For example, the N═C double bond may suitably be part of an aromatic heterocyclic ring having one or more N hetero atoms in the ring, optionally with one or more other hetero atoms selected from S and O. The heterocyclic ring may be substituted.
Desirably the said organic compound contains the structural element —N═C—S—S—C═N—, in which case both the N═C double bond and the C═N double bond may optionally be part of aromatic systems as described above, suitably two similar aromatic systems. More desirably the said organic compound is selected from dibenzothiazyl disulfide, 6,6′-dithiodinicotinic acid, 2,2′-dipyridyl disulfide, and bis(4-t-butyl-1-isopropyl-2-imidazolyl) disulfide. Of course, combinations of these organic compounds may also be used. Organic compounds having structural element —N═C—S—S—, which are useful as accelerators for accelerating the curing of CA adhesives if diluted in a solution, are described in WO 00/39229 and the corresponding U.S. Patent of Henkel KGaA, both of which were published after the first priority date of this application and the contents of which are incorporated herein by reference.
Desirably the activator comprises a member selected from the group consisting of pyridines, quinolines, pyrimidines and pyrazines substituted on the ring(s) with at least one electron-withdrawing group which decreases the base strength of the substituted compound compared to the corresponding unsubstituted compound.
An aromatic heterocyclic compound may suitably be monocyclic, bicyclic or tricyclic. The N hetero atoms(s) may be present in one or more of the rings. Two or more heterocyclic rings may be fused, or a heterocyclic ring may be fused to one or more carbocyclic rings. A heterocyclic ring may suitably be a 5- or 6-membered ring and may suitably have one or two N-atoms in the ring. A 6-membered heterocyclic ring is particularly suitable. In the case of two fused heterocyclic rings, the total number of N-atoms is suitably not more than three. The aromatic heterocyclic compounds are suitably substituted on the ring carbon atoms. A carbocyclic ring fused to a heterocyclic ring may suitably have 6 carbon atoms and/or may be an aromatic ring. A compound comprising a heterocyclic ring fused to a carbocyclic ring may be substituted by electron-withdrawing group(s) on either or both of the heterocyclic and carbocyclic rings.
Suitably the at least one electron-withdrawing group is selected from the group consisting of halo, CN, CF 3 , COOR, COR 4 , OR, SR, CONR 1 R 2 , NO 2 , SOR, SO 2 R 3 , SO 3 R 3 , PO(OR 3 ) 2 and optionally substituted C 6 -C 20 aryl, wherein R, R 1 , R 2 and R 4 (which may be the same or different) are H, optionally substituted C 1 -C 10 alkyl, or optionally substituted C 6 -C 20 aryl, and R 3 is optionally substituted C 1 -C 10 alkyl, or optionally substituted C 6 -C 20 aryl. Suitably the number of electron-withdrawing group(s) (which may be the same or different) may be from 1 to 3 groups per ring, for example 1 or 2 groups per ring.
For example, the electron-withdrawing group(s) may be selected from the group consisting of halo, CN, COOR and COR 4 . Desirably R 4 is optionally substituted C 1 -C 10 alkyl or optionally substituted C 6 -C 20 aryl. R, R 1 , R 2 , R 3 and R 4 may suitably be optionally substituted C 1 -C 5 alkyl, for example unsubstituted C 1 -C 5 alkyl.
The criterion that the electron-withdrawing group decreases the base strength of the substituted compound compared to the corresponding unsubstituted compound may be determined by pKa measurement in water under standard conditions (e.g. 25° C. and zero ionic strength) by conventional means or using a software package which calculates pKa of the base such as “ACD/pKa Calculator” available from Advanced Chemistry Development, 133 Richmond Street West, Suite 605, Toronto, ON N5H 2LS, Canada. A decrease in base strength is indicated by a reduction in pKa value.
The aromatic heterocyclic compound substituted with electron-withdrawing groups may also be substituted on the ring with one or more electron-releasing groups, provided that overall the base strength (i.e. the pKa) is reduced compared to the corresponding unsubstituted compound.
According to a particular aspect, the aromatic heterocyclic compound is selected from:
pyridines having one or more electron-withdrawing groups in the 3-, 3,4- or 3,5-position on the ring, suitably 3,5-dihalopyridines, such as 3,5-dichloropyridine or 3,5-dibromopyridine, or 3-cyano pyridine, a lower alkyl 3,5-pyridine dicarboxylate, or a 5-halo nicotinic acid such as 5-bromo nicotinic acid,
pyridines having an electron-withdrawing group in the 2 position on the ring, suitably a COOR or COR 4 group, such as 2-acetyl pyridine,
pyridines having an electron-withdrawing group in the 4-position on the ring, suitably 4-nitropyridine,
pyrimidines having an electron-withdrawing group in the 4- or 5-position on the ring, suitably 4- or 5-halo pyrimidines, such as 4-bromopyrimidine or 5-bromopyrimidine, nitroquinolines, suitably 5-nitroquinoline, polyhalogenated quinolines, suitably 4,7-dihalo quinolines such as 4,7-dichloro quinoline,
pyrazines having an electron-withdrawing group in the 2-position on the ring, suitably 2-methoxy pyrazine or 2-methylthio pyrazine.
and aromatic heterocyclic compounds which are substantially iso-electronic to any of the foregoing compounds.
According to one feature, the present invention provides an activator composition for the accelerated hardening of cyanoacrylate adhesives, wherein the activator comprises a member selected from the group consisting of:
aromatic heterocyclic compounds having at least one N hetero atom in the ring(s) and substituted on the ring(s)with at least one substituent selected from the group consisting of halo, CN, CF 3 , COOR, COR 4 , OR, SR, CONR 1 R 2 , NO 2 , SOR, SO 2 R 3 , SO 3 R 3 , PO(OR 3 ) 2 and optionally substituted C 6 -C 20 aryl, wherein R, R 1 , R 2 and R 4 (which may be the same or different) are H, optionally substituted C 1 -C 10 alkyl, or optionally substituted C 6 -C 20 aryl, and R 3 is optionally substituted C 1 -C 10 alkyl, or optionally substituted C 6 -C 20 aryl, mixtures of any of the foregoing with each other, and/or with N,N-dimethyl-p-toluidine, and mixtures of any of the foregoing and/or N,N-dimethyl-p-toluidine with an organic compound containing the structural element, —N═C—S—S—.
According to a further aspect, the present invention includes the use of a composition as defined above for the accelerated hardening of a cyanoacrylate adhesive. The composition may be applied to a substrate before application of the cyanoacrylate adhesive thereto, and/or the composition may be applied to the cyanoacrylate adhesive after application of the adhesive to a substrate.
According to a further aspect, the present invention provides an adhesive system comprising a cyanoacrylate adhesive together with a composition as defined above. Suitably, the composition as defined above is held separately from (i.e. does not contact) the adhesive prior to application on a substrate.
According to another aspect, the present invention provides a process for the bonding of substrates or parts, characterised by either of the following series of steps:
(a) dispensing an activator composition as defined above onto at least one surface of the substrates or parts to be joined; (b) optionally exposing solvent or other liquid vehicle in the activator composition to air, optionally with heating or with the aid of a fan; (c) optionally holding the substrate or part having the activator composition thereon for a retention or shipping period, (d) applying a cyanoacrylate adhesive to at least one substrate or part; (e) joining the substrates or parts, optionally with manual or mechanical fixing, and (f) optionally subsequently dispensing the activator composition onto adhesive exposed from a joint gap; or
(i) applying a cyanoacrylate adhesive onto at least one surface of the substrates or parts to be joined; (ii) joining the substrates or parts, optionally with manual or mechanical fixing; (iii) dispensing an activator composition as defined above onto the adhesive before or after the step of joining the substrates or parts, and (iv) optionally exposing solvent or other liquid vehicle in the activator composition to air, optionally with heating or with the aid of a fan.
Suitably the retention or shipping period in step (c) may be in the range from several minutes to several days, for example from two minutes to forty-eight hours. Optionally the activator composition may be applied onto parts prior to their shipping, forwarding or delivery to an end-user, customer or contractor.
The present invention includes a bonded assembly of substrates or parts bonded by a process as defined above. The present invention also includes as an article of commerce a substrate or part having a composition as defined above applied thereto.
According to another aspect, the present invention provides an activator composition for the accelerated hardening of cyanoacrylate adhesives, wherein the composition comprises a solution of one or more activators in a solvent mixture which comprises a volatile hydrocarbon and a cyclic ketone. Cyclic ketones as co-solvents have shown better results in reducing the “halo effect” discussed above than linear ketones such as acetone, butanone, pentanone, hexanone, 4-methyl-2-pentanone, or octanone; than cyclic ethers such as dioxane or tetrahydrofuran; or than adhesive-miscible solvents such as ethyl acetate.
Suitably, the cyclic ketone is present in an amount of up to about 15%, especially up to about 12%, particularly up to about 10%, by weight of the solvent mixture. If an amount substantially greater than 10%, and particularly greater than 15% is used, there may be a risk that a plastic substrate will be attacked. Desirably, the cyclic ketone is present in an amount of at least about 2.5% by weight of the solvent mixture. Below this amount the reduction in the “halo effect” may not be sufficient for full visual satisfaction. Preferably, the cyclic ketone is present in an amount of at least about 3% by weight of the solvent mixture. At or above this level the presence of cyclic ketone is seen to be beneficial. Desirably, the cyclic ketone is present in an amount in the range of 3% to 7.5% by weight of the solvent mixture, particularly an amount in the range of 4% to 7% by weight of the solvent mixture.
A cyclic ketone may suitably be monocyclic or bicyclic.
Suitably the cyclic ketone is an optionally-substituted cyclic ketone, desirably an alicyclic ketone, having 3-10 carbon atoms in the ring. A substituted cyclic ketone may be mono- or di-substituted on the ring with C 1 -C 5 alkyl, more particularly C 1 -C 2 alkyl.
One particular example of suitable cyclic ketone is cyclohexanone. Other examples include cyclobutanone, cyclopentanone, cycloheptanone and 2-methyl cyclopentanone. Examples of bicyclic ketones include 2-norbomanone, bicyclo[3.2.1]octan-2-one and bicyclo[2.2.2] octanone.
Desirably, the volatile hydrocarbon is an aliphatic hydrocarbon. Suitably, the volatile aliphatic hydrocarbon may have from 4 to 10 carbon atoms, particularly from 5 to 8 carbon atoms, and may be straight chain, branched or cyclic. One particular example of a suitable hydrocarbon is n-heptane.
In one aspect, the present invention relates to use of an activator composition as defined above for the accelerated hardening of a cyanoacrylate adhesive, particularly when the activator composition is applied to the cyanoacrylate adhesive after application of the adhesive to a substrate.
In an activator composition for the accelerated hardening of cyanoacrylate adhesives, the activator may suitably comprise a member selected from the group consisting of:
organic amines including: lower fatty amines, aromatic amines, dimethylamine and the like; aliphatic, alicyclic and, especially, tertiary aromatic amines; such as N,N-dimethylbenzylamine, N-methylmorpholine and N,N-diethyltoluidine;
amine compounds with a boiling point of between 50° C. and 250° C. such as triethylamine, diethylamine, butylamine, isopropyl amine, tributyl amine, N,N-dimethyl aniline, N,N-diethyl aniline, N,N-dimethyl-p-toluidine, N,N-dimethyl-m-toluidine, N,N-dimethylo-toluidine, dimethyl benzyl amine, pyridine, picoline, vinyl pyridine, ethanolamine, propanolamine and ethylene diamine;
organic compounds containing the structural element, —N═C—S—S— (as described above).
aromatic heterocyclic compounds having at least one N hetero atom in the ring(s) and substituted on the ring(s)with at least one electron-withdrawing group which decreases the base strength of the substituted compound compared to the corresponding unsubstituted compound (as described above),
and mixtures of any of the foregoing with each other.
According to one aspect, the present invention includes the use of an activator composition as defined above for the accelerated hardening of a cyanoacrylate adhesive. The composition may be applied to a substrate before application of the cyanoacrylate adhesive thereto, but more suitably the composition is applied to the cyanoacrylate adhesive after application of the adhesive to a substrate.
According to a further aspect, the present invention provides an adhesive system comprising a cyanoacrylate adhesive together with an activator composition as defined above. Suitably, the activator composition as defined above is held separately from the adhesive prior to application on a substrate.
According to another aspect, the present invention provides a process for the bonding of substrates or parts, characterised by the following series of steps:
(i) applying a cyanoacrylate adhesive onto at least one surface of the substrates or parts to be joined; (ii) joining the substrates or parts, optionally with manual or mechanical fixing; (iii) dispensing an activator composition comprising a solution of one or more activators in a solvent mixture which comprises a volatile hydrocarbon and a cyclic ketone onto the adhesive before or after the step of joining the substrates or parts, and (iv) optionally exposing the solvent mixture in the activator composition to air, optionally with heating or with the aid of a fan.
The process of the invention is particularly advantageous when at least one of the substrates has a surface of a dark colour or is transparent and/or at least one of the substrates is of a plastics material. However the invention is also useful with substrates of other materials such as cardboard, paper, or wood, particularly if the surface is of a dark colour.
The present invention includes a bonded assembly of substrates or parts bonded by a process as defined above.
Desirably, an activator composition comprises an amount of activator effective to accelerate hardening of a cyanoacrylate adhesive, the activator being carried in a suitable solvent mixture in accordance with the invention.
The solutions of the activator(s) may suitably contain the activator compound(s) in concentrations of from 0.01 to 10 g per 100 ml of solvent mixture; for example, from 0.05 to 5 g of activator substance are dissolved per 100 ml of solvent mixture.
Various conventional organic solvents are suitable as the hydrocarbon solvent (in the solvent mixture) for the activator(s) according to this aspect of the present invention, provided they have a sufficiently high volatility. Desirably, the boiling point of the solvent is below about 120° C., suitably below about 100° C., at ambient pressure. Although aromatic solvents such as toluene or xylene may be used, the hydrocarbon solvent is desirably an aliphatic hydrocarbon. Suitable solvents include specialized boiling point gasolines, but especially n-heptane, n-hexane, n-pentane, octane, cyclohexane, cydopentane, methyl cyclopentane, methyl cyclohexane and isomers of them like isooctane, methylhexanes, methylpentanes, 2,2-dimethyl butane (neohexane), or mixtures thereof, as well as petroleum benzines and ligroin.
DETAILED DESCRIPTION OF THE INVENTION
An alkyl group may be straight-chained or branched and may be unsaturated, i.e. the term alkyl as used herein includes alkenyl and alkynyl. A C 1 -C 10 alkyl group may for example be a C 1 -C 5 alkyl group. A lower alkyl group may suitably be a C 1 -C 5 alkyl group. An aryl group includes phenyl and naphthyl groups, either of which may be substituted with an alkyl group, more particularly a lower alkyl group. Halo includes chloro, bromo, fluoro and iodo, as well as pseudohalo-radicals such as CN, SCN, OCN, NCO, NCS.
An optionally substituted alkyl, alkoxy or aryl group may be substituted with a substituent selected from the group consisting of halo, CN, CF 3 , COOR, COR, OR, SR, CONR 1 R 2 , NO 2 , SOR, SO 2 R 3 , SO 3 R 3 , PO(OR 3 ) 2 and optionally substituted C 6 -C 20 aryl, wherein R, R 1 and R 2 (which may be the same or different) are H, optionally substituted C 1 -C 10 alkyl, or optionally substituted C 6 -C 20 aryl, and R 3 is optionally substituted C 1 -C 10 alkyl, or optionally substituted C 6 -C 20 aryl.
In an organic compound containing the structural element —N═C—S—S—, in which the N═C double bond is part of a heterocyclic ring, the heterocyclic ring may be substituted for example with optionally substituted C 1 -C 10 alkyl, optionally substituted C 1 -C 10 alkoxy, optionally substituted C 1 -C 10 alkoxyalkyl, halo, CN, CF 3 , COOR, COR, OR, SR, CONR 1 R 2 , NO 2 , SOR, SO 2 R 3 , SO 3 R 3 , PO(OR 3 ) 2 and optionally substituted C 6 -C 20 aryl or aryloxy, CSOR 3 , COONR 3 2 , NRCOOR, N═N—R 3 , OOR 3 , SSR 3 , OOCOR 3 , NOR 3 2 , ON(COR 3 ) 2 , S-aryl, NR 3 2 , SH, OH, SiR 3 3 , Si(OR 3 ) 3 , OSiR 3 3 , OSi(OR 3 ) 3 , B(OR 3 ) 2 , P(OR 3 ) 2 , SOR 3 , OSR 3 , wherein R,R 1 and R 2 (which may be the same or different) are H, optionally substituted C 1 -C 10 alkyl, or optionally substituted C 6 -C 20 aryl, and R 3 (which may be the same or different) is optionally substituted C 1 -C 10 alkyl, or optionally substituted C 6 -C 20 aryl.
Desirably, an activator composition comprises an amount of activator effective to accelerate hardening of a cyanoacrylate adhesive, the activator being carried in a suitable vehicle.
Suitably the activator composition is an activator solution of the activator in a solvent. Alternatively the composition may be a dispersion of the activator in a suitable vehicle, particularly a liquid vehicle.
Desirably, the activator(s) are dissolved in readily volatile organic solvents, such as hydrocarbons, carboxylic acid esters, ketones, ethers or halogenated hydrocarbons and carbonic acid esters or acetals or ketals. The solutions of the activator(s) may suitably contain the activator compound(s) in concentrations of from 0.01 to 10 g per 100 ml of solvent; for example, from 0.05 to 5 g of activator substance are dissolved per 100 ml of solvent.
When the activator composition contains a mixture of two activator compounds, the respective amounts of the activator compounds may vary and are only limited by respective amounts which will no longer be effective for the desired combination of properties. More particularly, when the activator composition contains a mixture of an aromatic heterocyclic compound substituted with at least one electron-withdrawing group and an organic compound having the structural element —N═C—S—S—, the activator compounds may suitably be present in amounts of about 0.1% to about 10% by weight of the said aromatic heterocyclic compound and about 0.01% to about 5% by weight of the said organic compound, more particularly about 0.05% to about 1%, of the said organic compound (c), based on the total weight of the activator composition.
Various conventional organic solvents are suitable as solvents for the activator(s) according to the present invention, provided they have a sufficiently high volatility. Desirably, the boiling point of the solvent is below about 120° C., suitably below about 100° C., at ambient pressure. Suitable solvents include specialized boiling point gasolines, but especially n-heptane, n-bromopropane, alcohols, for example isopropyl alcohol, alkyl esters of lower carboxylic acids, for example ethyl acetate, isopropyl acetate, butyl acetate, ketones, such as acetone, methyl isobutyl ketone and methyl ethyl ketone. Also suitable are ether solvents, ether esters or cyclic ethers, such as, especially, tetrahydrofuran. In the case of sparingly soluble activators, chlorinated hydrocarbons, such as dichloromethane or trichloromethane (chloroform), may also be used.
The activator compositions according to the present invention are suitable for the accelerated hardening of conventional cyanoacrylate adhesives which contain as the fundamental constituent one or more cyanoacrylic acid esters, suitably with inhibitors of free-radical polymerisation, inhibitors of anionic polymerisation and, optionally, conventional auxiliary substances employed in such adhesive systems, like fluorescence markers.
The cyanoacrylic acid esters used in the adhesives are in the main one or more esters of 2-cyanoacrylic acid. Such esters correspond to the following general formula:
H 2 C═C(CN)—CO—O—R 5 .
In that formula, R 5 represents an alkyl, alkenyl, cycloalkyl, aryl, alkoxyalkyl, aralkyl or haloalkyl or other suitable group, especially a methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, pentyl, hexyl, allyl, methallyl, crotyl, propargyl, cyclohexyl, benzyl, phenyl, cresyl, 2-chloroethyl, 3-chloropropyl, 2-chlorobutyl, trifluoroethyl, 2-methoxyethyl, 3-methoxybutyl or 2-ethoxyethyl group. The above-mentioned cyanoacrylates are known to a person skilled in the art of adhesives, see Ullmann's Encyclopaedia of Industrial Chemistry, Volume A1, p. 240, Verlag Chemie Weinheim (1985) and U.S. Pat. Nos. 3,254,111 and 3,654,340. Preferred monomers are the allyl, methoxyethyl, ethoxyethyl, methyl, ethyl, propyl, isopropyl or butyl esters of 2-cyanoacrylic acid. The monocyanoacrylic acid esters represent the largest proportion by weight of the polymerisable monomers in the adhesive.
The mentioned cyanoacrylic acid esters may suitably be present in the adhesives in amounts of from 99.99 to 90 wt. %. Preference is given to cyanoacrylic acid esters the alcohol radical of which is derived from alcohols having from 1 to 10 carbon atoms, which may also be cyclic, branched or perfluorinated.
The cyanoacrylate adhesives according to the present invention may also contain an inhibitor of free-radical polymerisation. Such inhibitors are, for example, hydroquinone, p-methoxyphenol, but also sterically-hindered phenols, phenothiazine and the like.
The cyanoacrylate adhesives according to the present invention may also contain thickeners as further auxiliary substances. That is desirable especially when there are to be bonded porous materials which otherwise readily absorb the low viscosity adhesive. Many types of polymer may be used as thickeners, such as polymethyl methacrylate, other methacrylate copolymers, acrylic rubber, cellulose derivatives, polyvinyl acetate or polyalphacyanoacrylate. A usual amount of thickener is generally about 10 wt. % or less, based on the total adhesive. In addition to or instead of the thickeners, the cyanoacrylate adhesives according to the present invention may also contain Reinforcing agents. Examples of such reinforcing agents are acrylic elastomers, acrylonitrile copolymers, elastomers or fluoroelastomers. Moreover, inorganic additives may also be used, for example silicates, thixotropic agents having a large surface area, which may be coated with polydi-alkylsiloxanes.
The cyanoacrylate adhesives according to the present invention may also contain substances for increasing the thermal stability thereof. There may be used for that purpose, for example, the sulfur compounds mentioned in European Patent specification No. 579 476.
In addition to or instead of the mentioned additives, the cyanoacrylate adhesives according to the present invention may also contain plasticisers. These serve to protect the resulting adhesive bond from brittleness. Such plasticisers are, for example, C 1 -C 10 alkyl esters of dibasic acids, especially of sebacic acid, phthalic acid or malonic acid. Other plasticisers are diaryl ethers and polyurethanes and the like. Furthermore, the adhesive preparations according to the present invention may also contain colorings, pigments, aromatic substances, extenders and the like, as well as fluorescing additives. Reference is directed to U.S. Pat. No. 5,749,956 (Fisher et al.), U.S. Pat. No. 4,869,772 (McDonnell et al.) and U.S. Pat. No. 5,314,562 (McDonnell et al.), the contents of which are incorporated herein by reference.
The activator compositions of the present invention are intended to be used with a wide variety of both metallic and non-metallic substrates, including substrates having acidic surfaces such as wood and paper or cardboard, and plastics substrates.
In the aspect of the invention using a cyclic ketone as a co-solvent, the advantage of the activator solutions of the invention is particularly evident on dark-coloured substrates.
The present invention will now be illustrated in greater detail.
EXAMPLES
In the Examples, the following abbreviations and terms are used:
DCP = 3,5-dichloro pyridine,
DBP = 3,5-dibromo pyridine,
NQ = 5-nitro quinoline
DCQ = 4,7-dichloro quinoline,
DPDS = 2,2′-dipyridyl disulfide,
BBID = Bis(4-t-butyl-isopropyl-2-imidazolyl)
disulfide,
DMPT = N,N-dimethyl-p-toluidine,
NBP = n-bromopropane,
Heptane = n-heptane,
CTV = cure through volume
CNP = 3-Cyano Pyridine
THF = tetrahydrofuran
<1% CNP = Saturated solution of
CNP in heptane, it was not fully soluble
at 1% concentration
BP = 5-bromo pyrimidine,
ACP - 2-acetyl pyridine
DPPDC = Dipropyl
3,5-Pyridine Dicarboxylate,
BNA = 5-bromo nicotinic
acid in IPA solvent
MPyr = 2-methoxy pyrazine;
MTPyr = 2-methylthio pyrazine
IPA = isopropyl alcohol solvent,
DIOX = 1,4-dioxane solvent
HPOL = heptan-1-ol solvent,
DCB = 1,2-dichloro benzene solvent
s = seconds
MS = mild steel
Loctite 401, Loctite 411,
Black Max/Loctite 380,
Loctite 416 and Loctite 424 =
Different grades of Loctite
ethyl cyanoacrylate-based adhesive
7457 = Loctite 7457 (activator)
7455 = Loctite 7455 (activator).
Loctite 401 (also called 401 herein) is a low viscosity, fast curing, single component ethyl cyanoacrylate adhesive (see for example U.S. Pat. No. 4,695,615).
Loctite 411 (also called 411 herein) is a single component high viscosity ethyl cyanoacrylate adhesive formulated for impact and peel resistance (see for example U.S. Pat. No. 4,477,607)
Black Max—Loctite 380—is a black, rubber toughened ethyl cyanoacrylate adhesive with enhanced resistance to peel and shock loads (see for example U.S. Pat. No. 4,440,910).
Loctite 424 is an ethyl cyanoacrylate adhesive particularly for bonding EPDM and other similar elastomers.
Loctite 416 is a high viscosity ethyl cyanoacrylate adhesive for bonding rubbers, plastics and metals.
Loctite 401: ethylcyanoacrylate; acidic stabilizer against anionic polymerization; antioxidant against radical polymerization; polymer thickening agent; curing accelerator (see for example EP-A-0151521 and EP-A-0259016).
Loctite 406: ethylcyanoacrylate; acidic stabilizer against anionic polymerization; antioxidant against radical polymerization; polymer thickening agent; adhesion promoter.
Loctite 407: ethylcyanoacrylate; acidic stabilizer against anionic polymerization; antioxidant against radical polymerization; polymer thickening agent; adhesion promoter (see for example WO 8200829 A1).
Loctite 410: ethylcyanoacrylate; acidic stabilizer against anionic polymerization; antioxidant against radical polymerization; polymer thickening agent; adhesion promoter; silica; toughening agent (see for example WO 8302450 A1)
Loctite 431: ethylcyanoacrylate; acidic stabilizer against anionic polymerization; antioxidant against radical polymerization; polymer thickening agent; curing accelerator.
Loctite 460: methoxyethyl cyanoacrylate; acidic stabilizer against anionic polymerization; antioxidant against radical polymerization; polymer thickening agent.
Loctite LID-3693: ethylcyanoacrylate+n-butylcyanoacrylate; acidic stabilizer against anionic polymerization; antioxidant against radical polymerization; polymer thickening agent; plasticizer (ester type); curing accelerator.
Loctite LID-3692: the same as LID-3693 except that it is of higher viscosity.
Sicomet 5195: ethylcyanoacrylate; acidic stabilizer against anionic polymerization; antioxidant against radical polymerization; polymer thickening agent
Loctite 7455 is a single component surface activator based on DMPT in heptane.
Loctite 7457 is another single component surface activator based on poly(oxypropylene) diamine in heptane.
Loctite is a trade mark. The above Loctite products are commercially available from Loctite Corporation, Rocky Hill, Conn., USA or Loctite (Ireland) Limited, Dublin 24, Ireland. The above Sicomet product is available from Sichel-Werke GmbH, Sichelstrasse 1, 30453 Hanover, Germany.
Permabond CSA activator is commercially available from National Starch & Chemical
Company, 10 Finderne Avenue, Bridgewater, N.J., USA.
ABS=acrylonitrile-butadiene-styrene terpolymer
PMMA=polymethylmethacrylate
The concentration of activator in an activator solution is expressed as % by weight based on the amount of solvent. The concentration of cyclohexanone is expressed as % by weight based on the total amount of solvent, the remainder being n-heptane.
pKa Values
The pKa values of the compounds used in the Examples together with those of the parent compounds are given below.
Activator Calculated pKa (±0.2)
Pyridine (parent)
5.32
CNP
1.78
Quinoline (parent)
4.97
NQ
2.8
Pyrimidine (parent)
1.29
DCQ
1.99
Pyrazine (parent)
1.0
DPPDC
1.84
DMPT
5.66
BP
−0.06
DCP
0.66
ACP
2.68
DBP
0.52
MPyr
0.81
Example 1
Post Spray tests were carried out by applying a 10 μl drop of adhesive onto a substrate and then spraying a chosen activator onto the drop. Full Cure Time is the time required for the adhesive drop to cure fully.
In Pre Spray tests the selected activator solution is sprayed onto the substrate before application of a 10 μl drop of adhesive. On Part Time is the time interval between application of the spray and addition of the adhesive drop.
The Post Spray cure speeds of a range of activators are shown in table 1. DCP, DBP and CNP provided faster Post Spray cure times than DMPT with Loctite 401 adhesive on a cardboard substrate, although good CTV performance was also obtained from the other activators listed.
TABLE 1
Post spray full cure times of various activators in heptane solvent for
a 10 μl drop of 401 adhesive on a cardboard substrate.
Activator
Conc (%)
Full Cure Time (s)
DMPT
1
15
DCP
1
10
DBP
1
12.5
CNP*
<1
6
NQ
3
7.5
DCQ
3
30
DPPD
1
30
BP
1
40-45
ACP
1
60
BNA+
1
195
*saturated solution in heptane was not fully soluble at 1% conc.
+IPA solvent
Table 2 compares the Post Spray performance of DCP and DBP with that of DMPT for various adhesive grades on cardboard and mild steel substrates. 3% levels of DCP were required to match the cure speed of 1% DMPT on a mild steel substrate. Similarly 3% levels of DCP and DBP were required to match the cure speed of DMPT with higher viscosity Black Max and 411 grades of adhesive on a cardboard substrate.
The difference in Post Spray cure speed of both DCP and DMPT with a fresh and less active aged sample of 401 on a cardboard substrate is shown in table 2. It is evident that DCP levels of ˜0.75% provided similar cure speeds to 1% DMPT for both the fresh and aged adhesive.
1% MPyr and MTPyr had post spray CTV times better than or at least as fast as those obtained with DMPT.
TABLE 2
Post Spray skin and full cure times of various activators
in heptane solvent for a range of different adhesive grades
with 10 ul drop of adhesive on cardboard and mild steel substrates.
Full Cure
Skin Time
Time
Activator
Conc (%)
Adhesive
Substrate
(seconds)
(seconds)
DMPT
1.0
Aged 401
Cardboard
nm
20-25
″
1.0
Fresh 401
″
″
15
DCP
0.25
Aged 401
″
″
50
″
0.5
″
″
″
30
″
0.75
″
″
″
20
″
1.0
″
″
″
15
″
0.25
Fresh 401
″
″
30
″
0.5
″
″
″
20
″
0.75
″
″
″
15
″
1.0
″
″
″
10
″
3.0
″
″
″
7.5
DBP
1.0
″
″
″
12.5
″
3.0
″
″
″
7.5
DMPT
1.0
411
″
15
25
DCP
1.0
″
″
15-20
45
″
3.0
″
″
15
25
DBP
1.0
″
″
15
45
″
3.0
″
″
15
25
DMPT
1.0
Black Max
″
30
150
DCP
1.0
″
″
40
210
″
3.0
″
″
30
120
DBP
1.0
″
″
75
225
″
3.0
″
″
30
135
DMPT
1.0
401
Mild Steel
nm
7.5
DCP
1.0
″
″
″
20
″
2.0
″
″
″
15
″
3.0
″
″
″
7.5
MPyr
1.0
401
Cardboard
″
6
MTPyr
1.0
401
Cardboard
″
20
(nm = not measured)
The Pre Spray cure speed of DCP, DBP, DCQ and NQ on a cardboard substrate is compared with DMPT in table 3. The results show that 3% levels of DCP were required to match the “On Part Time” performance of 1% DMPT. The performance of 1% DBP was closely similar to that of 1% DMPT. A notable feature of the results is the good long term “On Part Time” performance of DBP, NQ and DBP at 3% levels. NQ in particular showed no change in its curing behaviour even after an “On Part Time” of 24 hours.
Mpyr and MTPyr had pre spray CTV times slower than those obtained with DMPT. The beneficial effect of adding 10% of high boiling point solvents to 2 and 3% DCP in heptane is also illustrated in table 3.
TABLE 3
Effect of different activators, activator concentration, solvent
and activator “On Part Time” on the Pre Spray skinning and
full cure time of a 10 μl drop of 401 adhesive on a cardboard
substrate. The solvent is heptane unless otherwise indicated.
On Part
Conc.
Co
Time
Skin Time
Full Cure
Activator
(%)
Solvent
(minutes)
(minutes)
Time (minutes)
DMPT
1.0
None
1
0.3-0.5
1.0-1.25
″
″
″
15
1.5
2.75
″
″
″
60
5.0
7.0
″
″
″
180
9.0-9.5
12.0
DCP
″
″
1
1.0
2.0
″
″
″
15
4.0
7.0-7.5
″
″
″
60
7.0
10.5
″
2.0
″
1
1.0
2.0
″
″
″
15
3.5
6.0
″
″
″
60
6.0
9.5
″
3.0
″
1
0.17
0.6
″
″
″
15
0.75
1.5
″
″
″
60
3.5
6.0
″
″
″
180
7.5
11.0
″
2.0
10%
1
0.08-0.16
0.25
DIOX
″
″
″
15
1.5
2.25
″
″
″
60
3.5
6.0
″
″
″
180
8.0
8.5
″
3.0
10%
1
0.08-0.16
0.3
HPOL
″
″
″
15
1.25
1.5
″
″
″
30
2.75
4.75
″
″
″
60
3.0
5.0
″
″
″
180
7.5
8.5
DBP
1.0
none
1
0.3
0.5
″
″
″
15
″
4.75
″
″
″
30
″
7.5
″
″
″
60
″
1.5
″
3.0
″
1
0.08-0.16
0.25
″
″
″
15
″
0.25
″
″
″
30
″
0.25
″
″
″
60
1.3
2.5
″
″
″
120
2.5
5.5
″
″
″
180
12
17
DCQ
1.0
none
1
—
10.0
″
2.0
″
1
3.0
5.0
″
″
″
15
4.5
6.0
″
″
″
30
4.5
6.0
″
″
″
60
5.0
6.0
″
″
120
5.0
7.5
″
3.0
″
1
1.0
2.0
″
″
″
15
1.0
2.0
″
″
″
30
2.0
5.0
″
″
″
60
2.0
5.0
″
″
″
1080
2.5
5.0
NQ
3.0
100%
15
0.83
1.5
IPA
″
″
″
30
″
″
″
″
″
60
″
″
″
″
″
120
″
″
″
″
″
180
″
″
″
″
″
240
″
″
″
″
″
1440
″
″
MPyr
1.0
″
initial
14
MTPyr
1.0
″
″
1.25
15
10
“initial” = 20 seconds On Part Time. This allows time for solvent to evaporate.
The effect of high boiling point solvents on the Pre Spray performance of 1% DCP is illustrated in table 4. DCB and HPOL were particularly beneficial compared to the equivalent results with heptane solvent (c.f. table 3).
TABLE 4
Effect of high boiling point solvents on the Pre Spray performance of
1% DCP with a 10 μl drop of 401 adhesive on a cardboard substrate.
Full Cure
On Part Time
Skin Time
Time
Solvent
(minutes)
(minutes)
(minutes)
DIOX
1
1
2
″
15
4
5
″
60
11
13
″
120
30
>50
DCB
1
1
2.5
″
15
2
3
″
60
7
8
″
120
11
14
HPOL
1
2
3
″
15
2.5
3.5
″
60
7
8
″
120
10
13
The Pre Spray cure speed of DMPT, DCP and NQ on a mild steel substrate are compared in table 5. Mild steel was a slower substrate than cardboard (c.f. table 3). As already found with cardboard, 3% levels of DCP were required to match the performance of 1% DMPT. Again NQ showed no change in its curing behaviour even after an “On Part Time” of 24 hours.
TABLE 5
Comparison of Pre Spray activator (DMPT, DCP and NQ)
“On Part Time” versus full cure time for a
10 μl drop of 401 adhesive on a mild steel substrate.
On Part Time
Skin Time
Full Cure Time
Activator
Conc. (%)
(minutes)
(minutes)
(minutes)
DMPT
1.0
1
2
5
″
″
15
5
30-35
DCP
3.0
1
2
5
″
″
15
5
30-35
NQ
3.0
15
10
13
″
″
30
″
″
″
″
60
″
″
″
″
120
″
″
″
″
180
″
″
″
″
240
″
″
″
″
1440
″
″
It will be seen from the test results that the activator solutions according to the invention have comparable or better properties than equivalent DMPT solutions.
Example 2
Tables 6A and 6B show the results of a series of tests carried out with Loctite 424. The various activators and their concentrations in the designated solvents are set out in Table 6A. This Table also includes the results for tests for the Fixture time on mild steel lap shears. The activator solution is applied to one of the lap shears and time is then allowed to elapse before adhesive is applied onto the other mating part and the overlapping lap shears are squeezed together so that the adhesive forms a thin layer. The time periods at the heading of each column of results indicate the time span between application of the activator solution and the bringing together of the lap shears i.e. one minute, two hours or twenty-four hours. The fixture times are indicated in many cases as a range, the lower figure indicating the time at which the lap shears were not fixed and the higher figure indicating the time by which the lap shears were already fixed. The actual fixture time would therefore lie in the range indicated.
Table 6B gives further results of tests on the same Compositions Nos. 1 to 42 as set out in Table 6A. “Pre Activation” and “Post Activation” tests are fillet cure tests carried out on cardboard. In “Pre Activation” tests one drop of activator solution is applied onto cardboard, then one drop of adhesive is applied onto the activator, either immediately after the solvent has been evaporated from the activator solution or after waiting for an additional period of fifteen seconds thereafter. The adhesive is left to cure without a second substrate being applied to it. The cure time (in minutes) is measured by testing the adhesive fillet with a spatula. Curing (hardening) is obtained when the fillet is thoroughly solid.
In “Post Activation” tests, one drop of adhesive is applied to the cardboard substrate, and one drop of activator solution is then applied to the adhesive. Again the fillet of adhesive is left to cure without application of a second substrate. In the columns of results, the heading “Whiten.” indicates whitening of the surface, which is generally regarded as undesirable. “Crater.”, indicates cratering (uneven surface), which is also undesirable. These two “cosmetic” effects are important physical parameters in determining whether a commercial adhesive will be generally accepted by end users.
The column headed “Skin” indicates the time in seconds up to the appearance of skin formation on the adhesive. This is judged visually by a change of the shine on the surface. The column headed “Through” indicates the time in minutes up to full cure through the fillet of adhesive. This is checked by pressing with a spatula.
Tensile shear strength on grit blasted mild steel was tested by standard methods. The results given in the column headed “TSS” are in N/mm 2 .
Tests 1 to 11 show the use of an activator composition containing DPDS alone, and test 12 shows an activator composition based on BBID alone. These tests are not within the scope of the present invention. Tests 13 to 22 relate to an activator composition containing DCP alone and test 23 concerns a composition containing DBP alone. These compositions are in accordance with the invention. Test 24 is a comparative test using a DMPT solution of the prior art. Test 25, 26 and 27 are also comparative test using the commercially available activator composition Loctite 7457. Test 27A is another comparative test using the commercially available activator composition Loctite 7455.
Tests 28 to 42 use compositions based on combinations of activators in accordance with a special feature of the present invention.
The columns at the left hand edge of Table 6A facilitate comparison of the respective test results. Reviewing the key in columns a-k it will be seen that the marking in column a shows that test 28 relates to a combination of activators as used in tests 1 and 15. Likewise column b indicates that test 29 relates to a combination of the activator solutions used in tests 2 and 16 (NBP as solvent). The coding continues through to columns c to k in a similar manner.
The tests results in Table 6A and 6B are to be compared overall, taking account of the cosmetic effects as well as the technical data. It will be seen with reference to test 24 that the control example using DMPT shows a marked loss of fixture speed when there is a twenty-four hour time span between application of the activator solution and bringing together of the lap shears. There is also significant fixture speed loss with the use of 7457 and 7455. It will be seen by reference to tests 1 to 12 that when DPDS or BBID are used, that these activators have a pronounced accelerating action and almost no loss of surface activation. DCP and DBP, on the other hand, have relatively slow fixture times in this adhesive composition (Loctite 424).
Tables 7 and 8 show test results similar to those in Table 6B for activator compositions 26 and 28-37 but using Loctite 416 cyanoacrylate adhesive (Table 7) and Loctite 380 cyanoacrylate adhesive (Table 8).
When a combination of activators is used, particularly with formulations 28 to 41, it will be seen from the test results that good accelerating action and almost no loss of surface activation (e.g. after 24 hours) are achieved. In addition, the test results shown in Table 6B for the compositions containing combinations of activators are generally favourable as compared to those for DPDS or BBID alone. In particular, in the “Pre Activation” tests, the cure times for the combined activator compositions of tests 28 to 42 are generally significantly shorter than those for the comparable tests using DPDS or BBID alone.
Likewise, in the “Post Activation” tests the “cosmetic effects” are generally favourable in tests 28 to 42, and the Skin times and Through times are relatively short.
As seen, promising results have been found with combinations of DPDS and DCP.
The formulations 28-41 in particular show the following combination of properties:
1. No or no substantial loss of surface activation. 2. Fast cure after pre-activation. 3. No or no substantial shortcomings in cosmetics. 4. Fast through cure after post activation. 5. No or no substantial loss of bond strengths.
Activator solutions according to this invention would allow manufacturers to have long waiting periods between the steps of application of activator (surface activation) and application of adhesive (bonding parts).
Thus the invention can confer the following benefits:
Interruptions/breaks/hold-ups in production lines do not require repeated surface activation of the parts to be adhered. Parts to be bonded can be activated in advance by the supplier or a contractor. This could be advantageous if manufacturer does not want to equip his production lines with activator application stages. Large number of parts can be pre-treated in advance and be held in stock.
TABLE 6A
[% in (W/V)] Composition
Fixture [s]
Activator
(on MS)
k
i
h
g
f
e
d
c
b
a
No.
DPDS
BBID
DCP
DBP
DMPT
7457
7455
Solvent
1 min
2 h
24 h
1
0.05%
heptane
5-10
10-15
2
0.05%
NBP
10-15
15-20
3
0.15%
heptane
4
4-5
4
0.15%
heptane
4
4-5
5
0.15%
NBP
6
0.20%
heptane
4-5
4-5
5-6
7
0.20%
NBP
8
0.45%
heptane
9
0.45%
NBP
10
0.45%
heptane
4-5
4-5
4-5
11
0.45%
NBP
12
0.15%
NBP
20
20
13
0.45%
heptane
15-20
20-35
25-30
14
0.45%
NBP
15
0.50%
heptane
40-50
90-100
16
0.50%
NBP
50-55
90-100
17
1.00%
heptane
15-20
60-70
18
1.00%
NBP
40-50
80-90
19
1.40%
heptane
10-15
25-30
25-25
20
1.40%
NBP
21
1.50%
NBP
20-25
60-70
22
1.50%
heptane
10-15
30-40
23
2.00%
heptane
3
60
24
0.62%
heptane
20
120
25
+
3-4
20-25
75-80
26
+
5-10
20-30
27
+
5
35
27a
+
35-40
120-150
28
0.05%
0.50%
heptane
5-10
10-15
29
0.05%
0.50%
NBP
5-10
10-15
30
0.05%
1.00%
heptane
4-5
8-10
31
0.05%
1.00%
NBP
5-10
13-15
32
0.10%
1.25%
heptane
5-6
5-8
33
0.10%
1.25%
NBP
5-6
7-9
34
0.15%
0.50%
heptane
35
0.15%
0.50%
NBP
36
0.15%
1.00%
heptane
37
0.15%
1.00%
NBP
5-10
5-10
38
0.15%
2.00%
heptane
3
5
39
0.15%
0.62%
heptane
3-4
5-10
40
0.15%
1.00%
NBP
25
25-30
41
0.15%
2.00%
NBP
5-10
20
42
1.00%
0.62%
heptane
10
150
TABLE 6B
Pre-Activ. [min]
Post-Activation
TSS [N/mm2]
15 s after
[s]
[min]
(on GBMS)
No.
immed.
drying
Whiten.
Crater.
Skin
Through
wet
dry
1
6
11
trace
trace
30
9
17.7
18.6
2
5
110
no
slightly
30
4-5
3
12
55
trace
trace
30
12
4
23
32
no
trace
15
3
5
40
120
no
no
20
3
6
100
300
no
no
5-10
3
7
no
slightly
5-10
1
8
23
40
trace
trace
15
9
9
no
slightly
5
1
10
45
300
no
no
5-10
60
11
11
38
no
no
15
4-5
12
25
28
no
no
120
240
13
6
40
no
no
5-10
20
14
6
8
slightly
slightly
15-20
1
15
4
16
no
no
30
1-2
16
2-3
6
no
no
20
1-2
17
4
5
no
no
30
1-2
18
2
3
no
no
15
2
19
3
8
slightly
no
5-10
20
20
4
5
no
slightly
10
1
21
2
3-4
no
no
15
2
22
3
4
no
slightly
15
1
13.5
21.8
23
3
3-4
no
trace
10
1
24
4-5
10
no
trace
4
1-2
25
9
190
severe
no
5-10
20
26
2
13
severe
no
5
2-3
6.8
13.9
27
4-5
28
severe
trace
3
2
27a
5-6
14
trace
slightly
6
2
17.1
8-5
28
4
12
no
slightly
10
2
14.2
19.3
29
2
3-4
no
no
15
1
30
5
6
no
slightly
10
2
16
19.6
31
1-2
2
no
no
15
<1
15.3
17.4
32
4
5
no
slightly
10
1-2
33
1-2
2
no
no
10
<1
34
12
14
no
slightly
10
2
35
2
2-3
no
no
10
2
36
4
6
no
no
15
2
37
2
2-3
no
no
15
1
38
3-4
3
no
trace
3
1-2
39
3
11
no
trace
5
1-2
40
1-2
9
no
no
30
1
41
3
5
no
no
20
<1
42
3
3-4
no
trace
10
1
TABLE 7
Results with Cyanoacrylate adhesive LOCTITE 416:
Pre Activ.
Post-Activation
15 s after
[s]
[min]
No.
drying [min]
Whiten.
Crater.
Skin
Through
(Loctite
26
19
severe
slightly
10
1-2
7457)
28
5
no
slightly
20
1-2
29
13
no
slightly
15
0.5
30
3
no
slightly
15
1
31
10
no
slightly
10
0.5
32
4
no
slightly
10
0.5
33
4
no
slightly
10
0.5
34
5
no
slightly
20
1-2
35
15
no
slightly
10
0.5
36
5
no
slightly
15
1
37
12
no
slightly
15
0.5
TABLE 8
Results with Cyanoacrylate adhesive LOCTITE 380:
Pre Activ.
Post-Activation
15 s after
[s]
[min]
No.
drying [min]
Whiten.
Crater.
Skin
Through
(Loctite
26
27
severe
slightly
+
3
7457)
28
12
no
slightly
+
2
29
23
no
slightly
+
1
30
10
no
slightly
+
0.5-1
31
16
no
slightly
+
0.5-1
32
12
no
slightly
+
0.5-1
33
15
no
slightly
+
0.5-1
34
26
no
slightly
+
2
35
13
no
slightly
+
1
36
11
no
slightly
+
0.5-1
37
15
no
slightly
+
0.5-1
+ No skin formation with this adhesive;
fillet cures from bottom to top.
Example 3
Four drops of CA-adhesive were placed as a bead or fillet on a sheet of black ABS-plastic, then a large excess, (6 drops), of CA-activator solution was added on top of the bead. The adhesive was left to cure without application of a second substrate. After evaporation of the solvent, the specimens were judged. The results are shown in the following table 9.
In case of post application of large quantities of n-heptane based CA-activators on top of CA-beads or fillets, the cured adhesive is often surrounded by a white area (white halo). See Nrs. 1; 2; 3; 5; 7; 9; 11.
A few percent of cyclohexanone added to the activator formulations successfully combats this effect. See Nos. 4; 6; 8; 10; 13; 14.
It seems that addition of 3% cyclohexanone is beneficial but not sufficient to obtain the full effect; see Nr. 12., but in the case of 5% and 7% (see Nrs. 13; 14) no white halo formation is observed (except: a slight whitening still remains in the case of adhesive Loctite 407, which is a slow curing adhesive and which in the batch tested had a low reactivity).
Despite cyclohexanone's pronounced solvent properties towards several plastics (e.g. ABS) the mixtures mentioned in the table were not found to cause swelling of the plastic (neither the black ABS, nor PMMA).
TABLE 9
Activator
Loctite
Loctite
Loctite
Loctite
Loctite
Loctite LID
Sicomet
Nr.
Solution
401
407
410
431
460
3693
5195
1
Loctite 7455
hhh
hhh
hh
hhh
N
h
hh
2
Permabond
h
hh
h
hh
N
hhh
N
CSA ativator
3
1% DMPT
in n-heptane
hhh
hhh
hh
hhh
N
h
hhh
4
1% DMPT
in n-heptane/
—
—
N
N
—
—
N
5% cyclohexanone
5
0.4% DPDS
in n-heptane
hhh
hhh
hh
hh
h
hh
hhh
6
0.4% DPDS
in n-heptane/
—
—
N
N
—
—
N
5% cyclohexanone
7
1.5% 3,5-DCP
in n-heptane
hhh
hhh
hh
hhh
N
hh
hh
8
1.5% 3,5-DCP
in n-heptane/
—
—
N
N
—
—
N
5% cyclohexanone
9
0.95% DMPT;
in n-heptane
hhh
hhh
hh
hh
h
hh
hhh
0.09% DPDS
10
0.95% DMPT,
in n-heptane/
N
hh
—
N
N
N
N
0.09% DPDS
5% cyclohexanone
11
1.5% 3,5-DCP,
in n-heptane
hhh
hhh
hh
hhh
N
h
h
0.09% DPDS
12
1.5% 3,5-DCP,
in n-heptane/
hh
hh
hh
h
N
h
h
0.09% DPDS
3% cyclohexanone
13
1.5% 3,5-DCP,
in n-heptane/
h
h
N
N
N
N
N
0.09% DPDS
5% cyclohexanone
14
1.5% 3,5-DCP,
in n-heptane/
N
h
N
N
N
N
N
0.09% DPDS
7% cyclohexanone
Legend:
h slight white halo
hh white halo
hhh very strong white halo
N no halo
Example 4
Tests with other co-solvents like ethylacetate or acetone instead of cyclohexanone do not result in an attenuation of the white halo:
The tests were carried out in the same way as mentioned above in Example 3. The results are shown in Table 10. The activator solutions were 1.5% 3,5-DCP and 0.9% DPDS in solvent mixtures based on n-heptane with co-solvent; the concentration of co-solvent is expressed as percent by weight of the solvent mixture as mentioned in the left column.
TABLE 10
Co-Solvent
Loctite
Loctite
Loctite
Sicomet
Concentration
Co-Solvent
401
431
LID-3692
5195
3%
Ethyl acetate
h
hh
hh
hhh
5%
Ethyl acetate
hhh
hhh
hh
hhh
7%
Ethyl acetate
hhh
hhh
h
hhh
3%
Acetone
hh
hhh
hh
hhh
5%
Acetone
hhh
hhh
hh
hhh
7%
Acetone
hh
hh
hh
hh
Example 5
Further tests were conducted to compare cyclic ketones with linear ketones and cyclic ethers. As shown in Table 11, the results show that the cyclic ketones are effective in attenuating the white halo whereas the linear ketones and cyclic ethers tested are not.
TABLE 11
Loctite
Loctite
Loctite
Sicomet
Nr.
Activator
401
406
480
5195
1
1% DMPT
n-heptane/12% 1,4-dioxan
hhh
hhh
hh
hh
2
1% DMPT
n-heptane/12% THF
hhh
hhh
hh
hh
3
1% DMPT
n-heptane/6% butanone
hh
hhh
h
hh
4
1% DMPT
n-heptane/12% butanone
hhh
hhh
hh
hh
5
1% DMPT
n-heptane/16% butanone
hhh
hhh
hh
hhh
6
1% DMPT
n-heptane/3% 3-pentanone
hhh
hhh
hh
hh
7
1% DMPT
n-heptane/6% 3-pentanone
hhh
hhh
hhh
hh
8
1% DMPT
n-heptane/8% 3-pentanone
hhh
hhh
hh
hhh
9
1% DMPT
n-heptane/6% 2-hexanone
hh
hh
hh
h
10
1% DMPT
n-heptane/6% 4-methyl-2-
hhh
hh
h
hh
pentanone
11
1% DMPT
n-heptane/12% 4-methyl-2-
hhh
hhh
hhh
hh
pentanone
12
1% DMPT
n-heptane/16% 4-methyl-2-
hhh
hhh
hhh
hh
pentanone
13
1% DMPT
n-heptane/6% 3-octanone
hh
hhh
hh
hh
14
1% DMPT
n-heptane/12%
N
N
N
N
cyclobutanone
15
1% DMPT
n-heptane/3%
hh
hhh
h
hh
cyclopentanone
16
1% DMPT
n-heptane/6%
N
h
N
N
cyclopentanone
17
1% DMPT
n-heptane/12%
hh
hhh
N
hh
cyclopentanone
18
1% DMPT
n-heptane/3%
N
h
N
N
cycloheptanone
19
1% DMPT
n-heptane/6%
N
N
N
N
cycloheptanone
20
1% DMPT
n-heptane/8%
N
N
N
N
cycloheptanone
21
1% DMPT
n-heptane/6% 2-methyl
h
N
N
N
cyclopentanone
22
1% DMPT
n-heptane/12% 2-methyl
N
h
h
N
cyclopentanone
23
1.5% 3,5-DCP, 0.09%
n-heptane/12% 1,4-dioxan
hhh
hhh
hh
hh
DPDS
24
1.5% 3,5-DCP, 0.09%
n-heptane/12% THF
hhh
hhh
h
hh
DPDS
25
1.5% 3,5-DCP, 0.09%
n-heptane/6% butanone
hhh
hhh
hh
hh
DPDS
26
1.5% 3,5-DCP, 0.09%
n-heptane/12% butanone
hh
hhh
hh
hh
DPDS
27
1.5% 3,5-DCP, 0.09%
n-heptane/16% butanone
hhh
hhh
h
hhh
DPDS
28
1.5% 3,5-DCP, 0.09%
n-heptane/3% 3-pentanone
hhh
hhh
hh
hh
DPDS
29
1.5% 3,5-DCP, 0.09%
n-heptane/6% 3-pentanone
hh
hhh
hh
hh
DPDS
30
1.5% 3,5-DCP, 0.09%
n-heptane/8% 3-pentanone
hhh
hhh
h
hhh
DPDS
31
1.5% 3,5-DCP, 0.09%
n-heptane/6% 2-hexanone
hh
hhh
h
h
DPDS
32
1.5% 3,5-DCP, 0.09%
n-heptane/6% 4-methyl-2-
hhh
hhh
h
h
DPDS
pentanone
33
1.5% 3,5-DCP, 0.09%
n-heptane/12% 4-methyl-2-
hhh
hhh
h
hh
DPDS
pentanone
34
1.5% 3,5-DCP, 0.09%
n-heptane/16% 4-methyl-2-
hh
hhh
hh
hh
DPDS
pentanone
35
1.5% 3,5-DCP, 0.09%
n-heptane/6% 3-octanone
hhh
hhh
h
hh
DPDS
36
1.5% 3,5-DCP, 0.09%
n-heptane/12%
N
N
N
N
DPDS
cyclobutanone
37
1.5% 3,5-DCP, 0.09%
n-heptane/3%
hh
hh
h
h
DPDS
cyclopentanone
38
1.5% 3,5-DCP, 0.09%
n-heptane/6%
N
h
N
N
DPDS
cyclopentanone
39
1.5% 3,5-DCP, 0.09%
n-heptane/12%
hh
hhh
h
h
DPDS
cyclopentanone
40
1.5% 3,5-DCP, 0.09%
n-heptane/3%
h
N
N
N
DPDS
cycloheptanone
41
1.5% 3,5-DCP,0.09%
n-heptane/6%
N
h
N
N
DPDS
cycloheptanone
42
1.5% 3,5-DCP, 0.09%
n-heptane/8%
N
N
N
N
DPDS
cycloheptanone
43
1.5% 3,5-DCP, 0.09%
n-heptane/6% 2-methyl
N
N
N
N
DPDS
cyclopentanone
44
1.5% 3,5-DCP, 0.09%
n-heptane/12% 2-methyl
hh
hhh
N
N
DPDS
cyclopentanone
Legend:
h slight white halo
hh white halo
hhh very strong white halo
N no halo
— no data evaluated
Comparative tests described above are carried out using commercially-available adhesive compositions but the individual nature of these adhesive compositions is not essential to the disclosure of the invention. The behaviour of activator solutions is to be compared within each test in relation to a particular adhesive composition and not from test to test in different adhesive compositions.
Although the invention has been described above, many modifications and equivalents thereof will be clear to those persons of ordinary skill in the art and are intended to be covered hereby, the true spirit and scope of the invention being defined by the claims.
|
An activator composition for the accelerated hardening of cyanoacrylate adhesives, wherein the activator comprises a member selected from the group consisting of: aromatic heterocyclic compounds having at least one N hetero atom in the ring(s) such as pyridines, quinolines and pyrimidines and substituted on the ring(s) with at least one electron-withdrawing group which decreases the base strength of the substituted compound compared to the corresponding unsubstituted compound, mixtures of any of the foregoing with each other, and/or with N,N-dimethyl-p-toluidine, and mixtures of any of the foregoing and/or N,N-dimethyl-p-toluidine with an organic compound containing the structural element, —N═C—S—S—, such as dibenzothiazyl disulfide. 6,6′dithiodinicotinic acid, 2,2′-dipyridyl disulfide, and bis(4-t-butyl-1-isopropyl-2-imidazolyl)disulfide. An activator composition may comprise a solution of one or more activators in a solvent mixture which comprises a volatile hydrocarbon and a cyclic ketone.
| 2
|
BACKGROUND OF THE INVENTION
[0001] Sodium carbonate is a widely-used product, with many applications in foods, as well as many other applications such as in cleaning, textile, and other industrial and commercial applications. Much of worldwide sodium carbonate production uses a process known as the “Solvay process”, which involves the reaction of carbon dioxide produced by thermal decomposition of calcium carbonate, with a solution of sodium chloride and ammonia to produce sodium bicarbonate, followed by thermal decomposition of the sodium bicarbonate to form sodium carbonate. However, high capital costs involved with building and operating the Solvay process have invited alternative approaches for making sodium carbonate.
[0002] One such alternative type of process is described in U.S. Pat. No. 7,708,972, U.S. Pat. No. 8,202,659, and U.S. Patent Application Publication 2010/0147698 A1, the disclosure of each of which is incorporated by reference in its entirety herein. This process involves a carbonation reaction between carbon dioxide and an aqueous sodium hydroxide brine solution produced by electrolysis of a sodium chloride solution. Other features of this process include generation of carbon dioxide for the carbonation reaction by reacting calcium carbonate (e.g., from limestone) with hydrochloric acid, and generating the hydrochloric acid by reacting chlorine gas and hydrogen gas produced by the electrolysis. Additional features include separation and purification of the sodium carbonate produced by the carbonation reaction, and recovery and recycle of sodium chloride from the electrolysis byproducts. Although this process can be effective, it also has certain limitations, such as requiring high levels of sodium hydroxide (e.g., at least 25 wt. % concentration) and/or high temperature levels (e.g., above 100° C. or above 110° C.) in order to achieve target efficiency levels.
[0003] Many other processes have been used or proposed for the production of sodium carbonate, and each of them has its own advantages and disadvantages. However, new and different processes and systems for producing sodium carbonate, which may afford opportunities for improved performance, cost, reliability, process variation tolerance, etc., are always welcome in the art.
SUMMARY OF THE INVENTION
[0004] According to one aspect, a method of making sodium carbonate and/or sodium bicarbonate comprises reacting carbon dioxide gas with an aqueous solution comprising sodium hydroxide in the presence of a compound of the formula (I): Na + [X—O] − where X is Cl, Br, or I.
[0005] According to further aspects, the aqueous solution comprising sodium hydroxide is generated by electrolysis of a solution comprising sodium chloride. In further aspects, the compound according to formula (I) is sodium hypochlorite, which can be generated by reaction of water and chlorine gas formed by electrolysis of a sodium chloride solution.
[0006] According to another aspect, a system for producing sodium carbonate comprises: (a) an electrical cell reactor for electrolysis of a solution comprising sodium chloride, comprising a cathode chamber and an anode chamber separated by a membrane, an outlet connected to the anode chamber configured for collecting chlorine gas from the anode chamber, and an outlet connected to the cathode chamber configured for collecting an aqueous solution comprising sodium hydroxide from the cathode chamber; (b) a reactor for reacting a liquid comprising the aqueous solution collected from the cathode chamber in (a) with a gas comprising chlorine collected from the anode chamber in (a) to produce sodium hypochlorite; and (c) a carbonation reactor for reacting an aqueous liquid comprising the aqueous solution collected from the cathode chamber in (a) and sodium hypochlorite produced in (b) with a gas comprising carbon dioxide to produce sodium carbonate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The foregoing and other features, and advantages of the invention are described in the following detailed description taken in conjunction with the accompanying drawings in which:
[0008] FIG. 1 schematically depicts a representative embodiment of a process and system for producing sodium carbonate;
[0009] FIG. 2 schematically depicts another representative embodiment of a process and system for producing sodium carbonate; and
[0010] FIG. 3 schematically depicts another representative embodiment of a process and system for producing sodium carbonate.
DETAILED DESCRIPTION
[0011] Turning now to the figures, an exemplary system and process for making sodium carbonate is schematically depicted. As shown in FIG. 1 , system/process 10 is shown with carbonation reactor 12 , into which is fed an aqueous solution 16 comprising sodium hydroxide and a compound according to formula (I). The nucleophilic reaction between the carbon dioxide and the aqueous sodium hydroxide produces sodium carbonate product 18 . As used herein, “sodium carbonate” is defined broadly to include not only anhydrous sodium carbonate, but also hydrated sodium carbonates. The reaction between carbon dioxide and aqueous sodium hydroxide produces hydrated sodium carbonates and/or sodium bicarbonate. In some embodiments, hydrated sodium carbonates can be further processed to purify and subject the hydrated sodium carbonates to heat-induced desiccation to produce purified anhydrous sodium carbonate, and the sodium bicarbonate can be subjected to a heat-induced decomposition reaction to form sodium carbonate plus water and carbon dioxide.
[0012] Turning now to FIG. 2 , further detail is shown of an exemplary embodiment in which an aqueous solution of sodium chloride is subjected to hydrolysis to generate the sodium hydroxide for use in the carbonation reaction. As shown in FIG. 2 , a system/process 20 is shown with an electrolysis cell reactor 22 having an anode chamber 24 and a cathode chamber 26 separated by a membrane 25 that is impermeable to water, but selectively permeable to ions. Anode chamber 24 is initially charged with a solution or brine of sodium chloride and cathode chamber 26 is initially charged with water. The cathode and anode are subjected to a difference in electronegative potential through an external circuit to drive the electrolysis reaction, as is well-known in the art. The resulting electrochemical reactions produce hydroxide ions in the cathode chamber 26 , which combine with sodium ions that migrate from the anode chamber 25 through the membrane 25 to form sodium hydroxide. The resulting aqueous sodium hydroxide solution 16 exits the cathode chamber 26 , is combined with a compound according to formula (I) from stream 44 , and is delivered to the carbonation reactor 12 . A hydrogen stream 28 is also produced in the cathode chamber 26 . The anode chamber 24 produces a chlorine gas stream 30 and a dilute brine solution stream 17 . The hydrogen stream 28 and the chlorine gas stream 30 are delivered to HCl reactor 32 , where they are reacted together in a highly exothermic reaction to form hydrogen chloride stream, which is delivered to CO 2 -generating reactor 38 . Heat generated by the HCl reactor 32 can be used to provide heat for other parts of the process or for generating electricity, as is known in the art. The hydrogen chloride stream 34 is delivered to the CO 2 -generating reactor 38 , where it reacts with calcium carbonate, which can be provided by limestone as a raw material. The reaction of hydrogen chloride with calcium carbonate produces a carbon dioxide stream 14 , which is delivered to the carbonation reactor 12 . The CO 2 -generating reactor 38 also produces calcium chloride 39 , which can be disposed of as a waste stream and/or used in other process steps such as purification (e.g., desulfation) of brine compositions for use in the electrolysis reaction.
[0013] In some embodiments, the products of the electrolysis reaction can also be used to generate sodium hypochlorite as the compound according to formula (I) for the carbonation reaction. As shown in FIG. 2 , a portion of the chlorine gas stream 30 is directed to sodium hypochlorite reactor 42 , where it is reacted with aqueous sodium hydroxide solution an electrolysis reaction to form sodium hypochlorite. This reaction is well-known in the art and does not require further detailed explanation. The aqueous sodium hydroxide solution for the sodium hypochlorite reaction can be provided by diverting a portion of the aqueous sodium hydroxide solution 16 produced by the electrolysis cell reactor 22 to the sodium hypochlorite reactor 42 . Water 40 can be added to provide the appropriate concentration level of sodium hydroxide in the sodium hypochlorite reactor 42 . Sodium hypochlorite in stream 44 produced by the sodium hypochlorite reactor 42 is then introduced to the aqueous sodium hydroxide solution 16 upstream of the carbonation reactor 12 for use in the carbonation reaction.
[0014] Of course, the crude hydrated sodium carbonate 18 produced by the carbonation reactor is typically subjected to further purification processing in order to meet product specification targets. Such processing is shown in more detail in system 50 of FIG. 3 , along with details about the provision of sodium chloride and water to the electrolysis cell reactor 22 . As shown in FIG. 3 , the crude sodium carbonate stream 18 , which includes the reacted aqueous solution 16 and particles of hydrated sodium carbonate is delivered to separator 52 , which separates the hydrated sodium carbonate particles 18 ′ from the mother liquor 62 . The hydrated sodium carbonate particles 18 ′ are delivered to drying vessel 54 , where heated air stream 56 subjects the hydrated sodium carbonate particles 18 ′ to desiccation processing. Heat applied in the drying vessel 54 can also thermally decompose any sodium bicarbonate formed in the carbonation reactor 12 to form sodium carbonate, water, and CO 2 . Air/water vapor stream 58 is exhausted from the drying vessel 54 , while anhydrous sodium carbonate 18 ″ is produced as a final product.
[0015] FIG. 3 also shows further details about processing of the liquid product of the anode chamber 24 of the electrolysis cell reactor 22 . This liquid is depleted of sodium ions that migrated to the cathode chamber 26 and of chloride ions that formed chlorine gas stream 30 , and can be referred to as a dilute brine. The dilute brine stream 17 is delivered to purification section 19 , where one or more purification stages can involve desulfation, dechlorination, and/or dechloratation. The purified dilute brine 21 is delivered to sodium chloride source 66 such as a salt storage pile. The mother liquor 62 from the separator 52 is also delivered to the sodium chloride source 66 , along with water 64 , to generate saturated sodium chloride brine 68 . The saturated sodium chloride brine 68 is delivered to purification section 70 , where it can be subjected to purification stages including desulfation, calcium removal, and/or magnesium removal (depending on the purity of the sodium chloride source 66 ), after which it may be subjected to mechanical vapor compression to re-saturate the solution with sodium chloride. Purified saturated sodium chloride solution 72 is delivered to the cathode chamber 26 , and water 23 is delivered to anode chamber 24 of the electrolysis cell reactor 22 .
[0016] Although the present invention is not bound to or limited by any particular theory of operation, the carbonation reaction of carbon dioxide with aqueous sodium hydroxide is believed to proceed by nucleophilic addition to the electrophilic carbonyl groups on the carbon dioxide molecule. Again, not being bound by any particular theory of operation, the compound according to formula (I) such as sodium hypochlorite is believed to assist in the nucleophilic attack on the carbonyl groups to create the reactive carbonyl anion. Almost any amount of sodium hypochlorite can be used, with exemplary amounts ranging from 0.1 to 10 wt. % based on the total weight of the aqueous sodium hydroxide solution, more specifically from 0.5 to 5 wt. %, and even more specifically from 1 to 2 wt. %.
[0017] The amount of sodium hydroxide used for the carbonation reaction can also vary widely. Although the compound according to formula (I) can be effectively used in conjunction with sodium hydroxide levels in excess of 25 wt. % such as the sodium hydroxide levels described in the above-referenced U.S. Pat. No. 7,708,972, it was quite surprising that the formula (I) compound could, in some embodiments, help to provide sufficient reactivity so that lower levels of sodium hydroxide can be used. In some embodiments, the sodium hydroxide level is less than 35 wt. %, more specifically less than 25 wt. %, even more specifically less than 23 wt. %, and even more specifically less than 20 wt. %, based on the total weight of the aqueous solution. In some embodiments, the molar ratio of [formula (I) compound]:[NaOH] can range from 2.69×10 −3 :1.0 to 2.69×10 −1 :1.0, more specifically from 1.34×10 −2 :1.0 to 1.34×10 −1 :1.0, and even more specifically from 2.69×10 −2 :1.0 to 5.36×10 −2 :1.0.
[0018] The temperature of the carbonation reaction can also vary widely. Although formula (I) compounds such as sodium hypochlorite can be effectively used in conjunction with reaction temperatures in excess of 100° C. as described in the above-referenced US 2009/0260993 A1, it was quite surprising that the formula (I) compound could, in some embodiments, help to provide sufficient reactivity so that lower temperatures can be used. In some embodiments, the reaction temperature is less than 100° C., more specifically less than 105° C., even more specifically less than 110° C., and even more specifically less than 115° C. In some embodiments, exemplary reaction temperatures can range from 25° C. to 150° C. , more specifically from 50° C. to 100° C., and even more specifically from 70° C. to 85° C.
[0019] The invention is further described below in the following non-limiting example(s).
EXAMPLES
[0020] A reaction mixture was prepared by diluting 1000 mL of a (5% m/m) sodium hypochlorite solution with 3000 mL of water followed by the addition of 1000 grams of sodium hydroxide. The resulting solution was subsequently reacted with carbon dioxide gas which was introduced to the reaction mixture using an aerator. The reaction was conducted at atmospheric pressure at an autogenously generated temperature ranging from 60-85° C. The reaction was allowed to proceed for 90 minutes or until the production of sodium carbonate caused the formation of a mixture so dense that carbon dioxide could no longer be percolated through the sodium carbonate slurry. The sodium carbonate was recovered from the reaction vessel and dried in an oven at approximately 150° C. or in some instances the samples were dried using a microwave oven. The dried samples were heated further at 250° C. to dehydrate the sodium carbonate to its anhydrous form prior to analysis by acid titration. The isolated samples were determined to have greater than 99.5% purity.
[0021] While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description.
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A method of making sodium carbonate and/or sodium bicarbonate is disclosed in which carbon dioxide gas is reacted with an aqueous solution sodium hydroxide solution in the presence of a compound of the formula (I): Na + [X—O] − where X is Cl, Br, or I.
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RELATED APPLICATIONS
The present application claims priority to provisional applications U.S. 61/874,177 filed on Sep. 5, 2013 and U.S. 61/901,554 filed on Nov. 8, 2013, with both applications herein incorporated by reference in their entirety.
BACKGROUND OF THE INVENTION
Field of Invention
The present invention is in the technical field of energy storage devices. More particularly, the present invention is in the technical field of rechargeable batteries using iron electrodes, and specifically iron electrodes which have been chemically pre-formed (CPF) by a particular process using water.
Related Art
Rechargeable batteries often require several charge-discharge cycles prior to achieving optimum performance. During these early cycles, critical surface films are formed on the electrode surfaces that affect the performance of the cell during later cycling. These early cycles are commonly termed formation cycles in the battery industry. In the case of nickel-iron batteries (Ni—Fe), 30 to 60 formation cycles are typically needed to achieve the full capacity of the cell. Formation cycling sometimes requires cycling at varied temperature regimes which complicates the process. This formation process is expensive, time consuming, consumes electrolyte which needs replacing, and generates a significant amount of gas. Therefore, reducing the number of formation cycles and simplifying the formation process is a worthy goal.
Manohar et. al. in “Understanding the factors affecting the formation of Carbonyl Iron Electrodes in Rechargeable Alkaline Iron Batteries”, J. Electrochem. Soc., 159, 12, (2012) A 2148-2155, reported that one reason for the long formation time could also be the poor wettability of the iron electrode and the inaccessibility of the pores of the iron by the electrolyte. As the pores became more accessible the charge and discharge process produced a progressively rougher surface resulting in an increase in electrochemically active surface area and discharge capacity. Triton X-100, a surfactant, reduced the number of cycles required to achieve higher capacity presumably because it improved access of the electrolyte to the pores.
U.S. Pat. No. 3,507,696 teaches that a mixture of FeO and Fe 2 O 3 powders fused with sulfur at 120° C. yields an active material that may be used in an aqueous slurry to impregnate sintered nickel fiber plaques that can used as a negative electrode in a Ni—Fe battery. Several formation cycles are needed to achieve high capacity.
It would be of benefit to the industry to have an iron electrode which is conditioned prior to any charge-discharge cycle so as to minimize the need for formation cycles.
SUMMARY OF THE INVENTION
Provided is a process for preparing an electrode comprising an iron active material, which comprises:
i) fabricating an electrode comprising an iron active material, and
ii) treating the surface of the electrode with water to thereby create an oxidized surface. In one embodiment, the water comprises deionized water. In one embodiment the water is brushed onto the electrode.
In another embodiment, provided is an electrode which comprises an iron active material, and which electrode has been preconditioned prior to any charge-discharge cycle to have the accessible surface of the iron material in the same oxidation state as discharged iron negative electrode active material. The electrode is so preconditioned by treating the surface of the electrode with water. In one embodiment, the oxidation state of the conditioned iron active material is +2, +2/+3, +3 or +4.
Among other factors, the present invention provides a process and resulting iron electrode which addresses the mismatch in the state-of-charge (SOC) of the anode and cathode that is present during Ni—Fe cell assembly. Use of the present process to precondition the iron electrode decreases the number of cycles, and time to achieve cell formation, electrolyte consumption, hydrogen gas generated, and the amount of water needed to refill the cell. In general, the process leads to improved iron utilization in the cell.
BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWING
FIG. 1 is an illustration of the interparticle contact between active material particles and the space between particles or pores that can be filled with an aqueous solution to precondition the surface of the electrode particles.
FIG. 2 shows the capacity of Ni—Fe cells with and without preconditioned iron electrodes.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Provided by the present invention is a chemically preconditioned iron electrode and a method for its preparation. The present invention chemically treats the surface of an iron metal electrode with water after the electrode is assembled to provide a preconditioned iron electrode. It is expected that the process of the present invention is amenable to a continuous process, and is therefore simpler and of lower cost than existent processes.
The preconditioned electrode may be prepared from a standard iron electrode used in Ni—Fe cells. These iron electrodes can be comprised of iron particles or mixtures thereof with sulfur, nickel, or other metal powders, bonded to a substrate. In one embodiment, a conductive additive for the iron electrode comprises nickel, carbon black or copper. In one embodiment, an additive of the iron electrode comprises sulfur. In another embodiment, the coating of active material of the iron electrode comprises a binder for the iron or iron active material, and additives. The binder is generally a polymer such as PVA, or a rubber. The binder is generally a polymer such as PVA, or a rubber. The use of a PVA binder has been found to be quite beneficial and advantageous.
In one embodiment, the iron electrode comprises about 50-90 wt % iron powder, and in another embodiment from about 75-85 wt % iron powder; from about 5-30 wt % nickel powder, and in another embodiment from about 12-20 wt % nickel powder; from 0.5-5.0 wt % binder, and in another embodiment from about 2.0-5.0 wt % binder; and, from 0.25-2.0 wt % sulfur, and in another embodiment, from about 0.25-1.0 wt % sulfur. In one embodiment, the iron electrode comprises about 80 wt % iron powder, about 16 wt % nickel powder, about 3.5 wt % binder and about 0.5 wt % sulfur powder.
In one embodiment, the iron electrode can comprise additional conventional additives, such as pore formers. In general, the porosity of the iron electrode is in the range of from 15-50%, and in one embodiment from 35-45%.
The substrate used in the electrode can be comprised of a conductive material such as carbon or metal. The substrate for the iron electrode is generally a single layer of a conductive substrate coated on at least one side with a coating comprising the iron active material. Both sides of the substrate can be coated. In one embodiment, the coating on at least one side comprises iron and additives comprised of sulfur, antimony, selenium, tellurium, nickel, bismuth, tin, or a mixture thereof. The substrate is generally a metal foil, metal sheet, metal foam, metal mesh, woven metal or expanded metal. In one embodiment, the substrate for the iron electrode is comprised of a nickel plated steel. It is generally of porous construction such as that provided by a mesh, or grid of fibrous strands, or a perforated metal sheet. The iron electrode can also be sintered.
The iron electrodes of the present invention are chemically preconditioned by treatment with water. In the treatment with water, the water acts as an oxidant that oxidizes the iron surface. The use of water is quite beneficial in that it is an oxidizing material that is non-toxic and yields reduction or thermal decomposition products that are also non-toxic. The water and solutions used to pretreat the iron electrodes may or may not contain a surfactant. An example of a surfactant that may be used includes but is not limited to Triton X-100. In one embodiment, the water used comprises deionized water. The treatment of the electrodes may be accomplished by coating, dipping, brushing, spraying, or otherwise applying water to the electrode.
The length of time the electrodes are treated with the oxidizing gas can vary, but is generally until oxidation of the iron on the accessible surface of the electrode is observed. The temperature at which the treatment is made is generally ambient, but it can be at higher temperatures. After the treatment, the electrode can be dried, if needed. It can be air dried or in an oven, for example. This is to make sure all of the oxidizing agent is removed.
In one embodiment, the treatment of the iron electrode is continued until the accessible surface of the iron material of the electrode is in the same oxidation state as the electrode would in the discharged state. This is achieved by the oxidation treatment and can be determined using conventional methods available.
While not wishing to be bound by theory, it is believed that nickel-iron batteries may sometimes be assembled with the nickel cathode (positive electrode) in its discharged state and the iron anode (negative electrode) in its charged state. Thus, when the cell is assembled, there is a mismatch between the state-of-charge (SOC) between the anode and cathode which is corrected during the formation process. During the formation process, it is believed that the low capacity of the early cycles is due to the limited amount of discharge products (ie. Fe(OH) 2 , Fe(OH) 3 , and Fe 3 O 4 depending on depth of discharge) that are formed until the proper conductivity, texture, and porosity of the iron electrode is achieved. Consequently, the negative electrode is in a higher SOC than the positive electrode for most of the formation process.
During the charge of a Ni—Fe cell there are typically two processes that occur at the anode surface, which are shown in Equations 1 and 2 below. Equation 1 is the desired conversion of discharge product, Fe(OH) 2 , to iron metal. Equation 2 is the reduction of water to hydroxide and hydrogen gas. The two processes have very similar electrochemical potentials and both are usually active during the charge process.
Fe(OH) 2 +2 e − →Fe+2OH − E°=−0.877 V 1
2H 2 O+2 e − →H 2 +2OH − E°=−0.828 V 2
However, when the negative electrode is at high SOC as in formation, the reaction in Equation 2 is more dominant since there is too little Fe(OH) 2 or other iron compounds with iron in its +2 or +3 oxidation state to accept current from the cathode. The reaction in Equation 2 consumes the water in the electrolyte which needs to be replaced and generates significant amount of gas that can become trapped between the electrodes, further hindering desired electrochemical reactions at the electrode surfaces. Gas generation can cause loss of adhesion of the active material to the electrode further damaging the electrode.
It is believed that chemically pretreating the electrode with water converts areas of the electrode that are accessible by the alkaline electrolyte, including pores, to iron hydroxides and/or iron oxides that are capable of being reduced to iron metal when an electrochemical current is applied in a cell. The products of the pretreating of the iron electrode may be the same as the discharge products on the iron electrode, or may be different. Following the treatment, the products may comprise independently or as a mixture: Fe(OH) 2 , Fe(OH) 3 , Fe 3 O 4 , Fe 2 O 3 , FeO, and other iron oxides. As a result, the mismatch in the SOC of the anode and cathode that is present during Ni—Fe cell assembly is minimized, if not avoided all together. Use of the present process to prepare the iron electrode thereby decreases the number of cycles and time to achieve cell formation, electrolyte consumption, hydrogen gas generated, and the amount of water needed to refill the cell.
FIG. 1 shows a diagram of an electrode that has been preconditioned. The iron particle active material, 1 , retains interparticle contact, 2 , and electrical contact between the active materials and the substrate, 3 , is maintained. The surface of the electrode and the pores, 4 , are able to be contacted by the water for preconditioning. Areas where there is interparticle contact are not oxidized. Because the oxidation products are electrically insulating, it is an advantage of this invention that the areas where there is interparticle contact are not oxidized, maintaining a conductive network between particles.
The present example is provided to further illustrate the present invention. It is not meant to be limiting.
EXAMPLE
An aqueous slurry consisting of 80% iron, 16% nickel, and 0.5% sulfur powders with 3.5% polyvinyl alcohol binder were pasted onto a perforated nickel sheet which was then dried. This sheet was then chemically preconditioned by brushing with deionized water and allowed to dry in air for 16 hours at room temperature followed by drying in an oven at 190° C. for 15 minutes. A 16% weight gain was measured and a slight orange-brown color was observed on the surface of the electrode. Two sample electrodes were cut from this sheet and tabs were TIG welded to the top uncoated area of the electrode. Two sample cells were constructed using these negative electrodes by placing the negative electrode between two commercial Histar sintered positive nickel hydroxide electrodes. Both the positive and negative electrodes were pocketed into polypropylene separator. For comparison, two identical cells were constructed from identical materials except that the negative electrodes were not chemically preconditioned. The test cells containing CPF iron negative electrodes and the control cells were subjected to an accelerate life test at 55° C. with the following charge regime:
Cycle 1 (@ Room Temp):
Charge: 1.0 A × 1.5 hrs
Rest: 30 Min
Discharge: 0.1 A to 1.0 V
Rest: 30 Min
Cycle 2-100 (@ 55° C.):
Charge: 1.0 A × 1.5 hrs
Rest: 30 Min
Discharge: 0.1 A to 1.0 V
Rest: 30 Min
The cycling characteristics for cells prepared with iron electrodes that have been preconditioned in accordance with the present invention is shown in FIG. 2 . The cells with chemically pre-conditioned negative electrodes deliver a capacity of 140-160 mAh/g Fe after only five cycles compared to a capacity of 120-135 mAh/g Fe after ten cycles for cells with negative electrodes that were not preconditioned. Furthermore, the overall capacity for cells with preconditioned electrodes is between 17-19% higher for the life of the cell after formation demonstrating a further advantage of this invention.
While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combination, and equivalents of the specific embodiment, method, and examples therein. The invention should therefore not be limited by the above described embodiment, method and examples, but by all embodiments and methods within the scope and spirit of the inventions and the claims appended therein.
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Provided is a process for preparing an electrode comprising an iron active material. The process comprises first fabricating an electrode comprising an iron active material, and then treating the surface of the electrode with water to thereby create an oxidized surface. The resulting iron electrode is preconditioned prior to any charge-discharge cycle to have the assessable surface of the iron active material in the same oxidation state as in discharged iron negative electrodes active material.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to novel stable acrylamide or methacrylamide monomers and their method of preparation.
2. Description of the Prior Art
U.S. Pat. No. 2,451,436 relates to N-alkyl acrylamides and their method of preparation. Likewise, the article in JACS 74, 6281 (1952) by J. G. Erickson is concerned with the preparation and stability of beta-dialkylacrylamides and also sets out the synthesis of N,N-dialkylacrylamides prepared therefrom.
However, to date there has been no method described of preparing stable primary or secondary aminoalkyl acrylamides or methacrylamides existing in free base form. Said stable monomers in base form are unknown in the art.
SUMMARY OF THE INVENTION
The invention relates to stable N-(ω-monoalkylaminoalkyl) acrylamide or methacrylamide monomer characterized by the following formula: ##STR2## where R 1 and R 2 are hydrogen or methyl, R 3 is isopropyl or t-butyl and n is 2 or 3 with the proviso that when R 1 is hydrogen, R 3 is t-butyl. These stable monomers may be prepared by condensing one mole of an acrylic or methacrylic compound having the structure: ##STR3## where R 1 is hydrogen of methyl and X is selected from the group consisting of halo, OH, or --OR 4 where R 4 is lower alkyl, with a diamine having the structure:
R.sub.2 NHC.sub.n H.sub.2n NHR.sub.3
where R 2 is hydrogen or methyl, R 3 is isopropyl or t-butyl and n is 2 or 3 to provide an intermediate compound having the structure: ##STR4## where R 1 , R 2 , R 3 , and n have a significance as above defined, and heating said intermediate compound at a sufficient temperature to split off one mole of said reactant diamine to yield said N-(ω-monoalkylaminoalkyl) acrylamide or methacrylmide. When acrylic acid is an initial reactant, R 3 in the above formula is t-butyl.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The invention relates to the synthesis of the above described N-(ω-monoalkylaminoalkyl) acrylamides or methacrylamide monomers. To prepare these materials there is first provided an acrylic or methacrylic compound having the structure: ##STR5## where X is halo, OH or --OR 4 is lower alkyl, with R 1 being hydrogen or methyl. The acrylic or methacrylic compound may be in acid ester or acid halide form. When the acid halide is employed it is preferred that the acid chloride be utilized such that X is chloro. When the ester form is utilized it is greatly preferred that the methyl or ethyl ester be used as a reactant.
The above acrylic or methacrylic compounds are reacted in at least a 1:2 mole ratio with a diamine having the structure:
R.sub.2 NHC.sub.n H.sub.2n NHR.sub.3
where R 2 is hydrogen or methyl, R 3 is isopropyl or t-butyl and n is 2 or 3. When acrylic acid is employed as a reactant, R 3 is t-butyl. In a preferred embodiment the diamine reactant is present in an excess over the theory required of 2 moles of diamine per mole of acrylic or methacrylic reactant. More preferably, 2-3 moles of diamine is reacted per mole of acrylic or methacrylic compound. Most preferably, the mole ratio of diamine to acrylic or methacrylic compound is 2.2-2.6 moles:mole.
In the first step of the process of the invention one mole of the amine reacts across the double bond with the other mole amidifying the acrylic or methacrylic compound. This first step of condensation may take place over a wide range of time and temperature conditions depending upon the particular reactants involved and other variables. Generally, the reaction is complete in 1/2-24 hours, more often 1-10 hours. Usually the temperature of reaction is 150°-190° C, and the reaction itself is effected under a pressure of 1-20 atmospheres. The reaction may be carried out in presence or absence of solvent. When a solvent is present it should be unreactive with both the reactants and products. Preferred solvents when utilized, are those which assist the condensation reaction by forming an azeotrope with the water of condensation, facilitating removal of this water. The reaction is thereby driven to completion in a relatively short time. Solvents of this type include toluene, benzene, xylene, etc. as well as aliphatics, halogenated aromatics and high boiling ethers, etc.
An intermediate compound is then prepared in the condensation step as follows: ##STR6## where R 1 , R 2 , R 3 , and n have a significance as above defined. This intermediate compound is then heated at a sufficient temperature to split off one mole of the reactant diamine to yield the desired N-(ω-monoalkylaminoalkyl) acrylamide or methacrylamide. The monomeric product so formed by splitting off one mole of diamine has been found to be stable in the free base form. This second step in the process of the invention is usually carried out again over a wide range of time and temperature variables. Usually this heat step or pyrolysis is effected under vacuum at a high temperature relative to the temperature of condensation in the first step of the reaction. Usually the pyrolysis is complete in 1/4-10 hours and more often 1/2-5 hours. The usual temperature range is 180°-280° C. under vacuum conditions of 1-75 mm.
After completion of the pyrolysis reaction the desired monomer is recovered from the pyrolysis overhead. The acrylamide or methacrylamide monomers are separable from the diamine by various means such as by subsequent fractionation of the co-distilled product.
It was surprising to discover that certain N-(ω-secondary aminoalkyl) acrylamides and methacrylamides could be prepared in good yield which were stable upon storage under ambient conditions in free base form. First, from prior art work one would believe that such materials would be unstable due to predicted addition of the amino group to the double bond in a form of a Michael addition. Thus, such instability by reason of conversion of the secondary aminoacrylamides or methacrylamides to substituted poly(beta-alanines) would be illustrated by the following reaction scheme: ##STR7## where R 1 and R 2 are hydrogen or methyl, R 3 is lower alkyl, n is two or three, and m is some higher integer. However, surprisingly the specific monoalkyl aminoalkyl acrylamide or methacrylamides in free base form falling within the scope of the disclosure here are stable.
It is also noteworthy to point out that the prior art is replete with instances where the acylation of monosubstituted diamines proceeds via ring closure to imidazolines and tetrahydropyrimidines rather than to the alkyl aminoalkylamides. Cyclization reactions of this type are disclosed in the following articles: "Imidazole and Its Derivatives, Part I," A. Weissberger, pp. 213-243, Interscience, New York, N.Y. (1953); "The Pyrimidines, Supplement I," A. Weissberger, pp. 331-333, Wiley-Interscience, New York, N.Y., (1971); JACS 1939, 822-4; A. J. Hill and S. R. Aspinall; JACS 1939; 3195-7, S. R. Aspinall; JACS 1948, 1629-1632, J. L. Riebsomer; and J. Org. Chem., 1947, 577-586, Al Kyrides et al. It was particularly interesting to note that even when a hindered alkylene diamine was employed such as in the Riebsomer work nevertheless imidazolines were still the favorite product.
Other compounds closely related to those described here were attempted to be synthesized. However, in many instances they could not be prepared or the resultant monomers were unstable.
Typical compounds includable within the scope of the invention are the following: ##STR8##
The following examples illustrate preparation of typical compounds falling within the scope of the invention. It is understood that the examples are merely illustrative and that the invention is not to be limited thereto.
EXAMPLE 1
Methacrylic acid (516 g., 6 moles) and 3-isopropylaminopropylamine (1715 g., 15 moles) were reacted in a stirred autoclave at 175° C for 2 hours. The resulting mixture was transferred to a three liter, three neck, round bottom flask equipped with thermometer and distillation column topped with a take-off head. Over a 2 hour period the pot temperature was brought to 175° C while about one equivalent of water was distilled and collected. The pot temperature was held at 175° C for an additional two hours. The excess 3-isopropylaminopropylamine was recovered as an overhead product (341 g., B.P. 55°/7 mm.). During the distillation the pot temperature was not allowed to exceed 150° C. The pot residue, 1698 g., consisted of N-isopropylaminopropyl methacrylamide (10 ± 3%) and the substituted propionamide (I) (85 ± 5%). ##STR9## The pyrolysis of this bottoms product was conducted in a 500 ml., three neck flask equipped with thermometer, feed line and distillation column topped with take-off head. An initial charge of 250 g. of feed and 1 g. of N,N'-diphenylphenylenediamine was brought to 230° ± 20° C at 30 mm. pressure. The pyrolysis products, N-isopropylaminopropyl methacrylamide and 3-isopropylaminopropylamine, were codistilled at 160° ± 15° C/30 mm. Additional feed, inhibited by 1000 ppm of N,N'-diphenylphenylenediamine, was added continuously at 200 ± 20 g./hour, matching the overhead production rate. When 1,540 g. of feed had been charged, the feed line was closed but pyrolysis was continued until only 30-40 g. of material remained in the pot. A total of 1515 g. of distillate was collected. The yield of N-isopropylaminopropyl methacrylamide, b.p. 126°-128° C/1 mm., was 85% of theoretical, based on methacrylic acid.
EXAMPLE 2
Methyl methacrylate (35 g., 0.35 mole) and 3-isopropylaminopropylamine (125 g., 1.10 mole) were reacted at 175° C for 2 hours in a rocking autoclave. Following removal of excess 3-isopropylaminopropylamine by distillation at 50 mm., 150° C maximum pot temperature, the bottoms were pyrolyzed at 240° ± 10° C at 50 mm. in a flask equipped with a column and take-off head. The collected reaction products, 79 g., were co-distilled at 165° ± 10° C. as formed. Subsequent fractionation recovered 3-isopropylaminopropyl amine and N-isopropylaminopropyl methacrylamide, 47 g., 72% based on methyl methacrylate.
EXAMPLE 3
By a procedure similar to that of Example 2, methyl methacrylate, 70 g., and 3-tert-butylaminopropylamine, 240 g., were reacted and the corresponding condensation products pyrolyzed. From the pyrolysis overhead were recovered 3-tert-butylaminopropylamine and N-tert-butylaminopropyl methacrylamide, b.p. 122°-123°/0.25 mm., 107 g., 84% of theoretical based on methyl methacrylate.
EXAMPLE 4
Using a procedure similar to that of Example 2, methyl methacrylate (600 g., 6 moles) and N-methylaminopropylamine (1500 g., 17.5 moles) were reacted to give 1307 g. of a condensation product after removal by distillation of methanol and excess diamine. Analysis of this residue by NMR indicated it to be a mixture of substituted propionamides (II) and (III): ##STR10## Part of the condensation product, 1210 g., was pyrolyzed at 200° to 220° C. under 45 mm.Hg. pressure. The pyrolysis product, 1026 g., was collected at 135° ± 5° C. Fractionation of 761 g. of this material provided the following distillation cuts.
______________________________________Fraction B.P., ° C. Pressure, mm. G.______________________________________1 55-8 3 912 58-75 3 1043 75-86 3 404 86-105 4 395 105-113 4 426 113-119 4 547 119-120 4 458 115-120 4 28______________________________________
spectral analysis by IR and NNR indicated that these cuts are mixtures of 1,2-disubstituted tetrahydropyrimidine derivatives, N-methylaminopropyl methacrylamide and N-aminopropyl-N-methyl methacrylamide and their Michael condensation derivatives.
EXAMPLE 5
Methacrylic acid (25 g., 0.68 mole) and isopropylaminoethylamine (68 g., 0.28 mole) were reacted at 175° to 180° C. for 3 hours in a 250 ml., 3-neck flask equipped with distillation means. During the reaction approximately one equivalent of by-product water was taken overhead. The bottoms product was pyrolyzed as described in Example 1. From the pyrolysis overhead product was recovered by distillation isopropylaminoethyl methacrylamide (22 g.), BP 127° C. and 11 mm. Hg pressure. As indicated by NMR analysis, isopropylaminoethyl methacrylamide is stable for at least two weeks at room temperature.
EXAMPLE 6
By a procedure similar to that of Example 1, acrylic acid, 150 g., and 3-tert-butylaminopropylamine, 670 g., were reacted and three-quarters of the resulting condensation product pyrolyzed at 230° C. and 50 mm. pressure. The pyrolysis reaction yielded two major fractions: a 254 g. fraction, BP 150°-164° C., at 50 mm. and a 170 g. fraction, BP 180°-184° C. From the higher boiling fraction, was recovered by distillation tert-butyl-aminopropylacrylamide, BP 125°-127° C. at 0.25 mm., 133 g. The stability of tert-butylaminopropylacrylamide was confirmed by NMR analysis of a 25% solution of tert-butylaminopropylacrylamine in deuterated chloroform over a period of three weeks.
EXAMPLE 7
By a procedure similar to that of Example 1, acrylic acid, 288 g., and isopropylaminopropylamine, 1140 g., were reacted and the resulting condensation produce pyrolyzed at 230° C. and 50 mm. Hg pressure. Fractionation of the pyrolysis overhead product provided the following cuts:
______________________________________Cut BP Pressure g.______________________________________1 35° C 0.25 295 g.2 35-70° C. 0.25 45 g.3 60-110° C. 0.25 24 g.4 110° C. 0.25 35 g.Pot residue 254 g.______________________________________
Cut 4 was analyzed by NMR spectroscopy after it had stood at room temperature overnight. The result indicated that the sample was a polymeric alanine derived from isopropylaminopropylacrylamide with almost complete absence of monomer. Thus, it can be seen that with respect to the above formula defining the products of the invention, that when R 1 is hydrogen, R 3 must be t-butyl.
EXAMPLE 8
Utility of a typical compound of the invention, N-(3-isopropylaminopropyl) methacrylamide was demonstrated by using it as a catalyst in the preparation of a flexible polyurethane foam. The following components were used in the formulation.
______________________________________ Parts by Weight______________________________________Polyoxypropylene triol, m.w. 3500 100Water 4.0Niax L-520 silicone surfactant 1.0F10 catalyst (50% stannous octoate) 0.6N-(3-isopropylaminopropyl) methacrylamide 0.1Toluene diisocyanate 48.3______________________________________
All of the above ingredients were stirred rapidly at room temperature as the diisocyanate was quickly poured in. After mixing, the blend was poured into a box. Cream time was 12 seconds and rise time 112 seconds. The resultant foam was of uniform cell structure and had a density of 1.9 pcf.
In addition to the just disclosed utility of the compounds of the invention as polyurethane catalysts, the cationic monomers also find use in additional areas of utility. For example, the cationic monomers, or polymers or copolymers, resulting therefrom may be used as retention aids for fiber furnishes in the paper industry, as additives used for improving drainage through the wire surface of Fourdrinier machine, as additives in cellulosic materials for the purpose of retaining dye added thereto, as polyelectrolytes in the coagulation of low turbidity water, and as additives useful in the flocculation or de-watering of sewage, the settling of coal slurries, the coagulation of rubber latex, and the breaking of oil-in-water emulsions. Likewise, the monomers, homopolymers or copolymers thereof may be used as additives in a number of processes or employed per se to produce a variety of manufactured articles. For example, solutions of resulting polymers may be cast or spun into shaped articles, sheets, films, wrapping tissues, tubing, filaments, yarns, threads, etc. For example, aqueous or alcoholic solutions of polymers made from the cationic monomers described here may be used in coating, finishing casting or molding for adhesion or lamination. Specifically, they may be used as adhesives for cellophane, paper, cloth, etc., as finishes for fabrics, as permanent sizes for yarns, as protective water resistant coverings, for use as sausage casings, as dye intermediates, as filament film formers, etc. The polymers may also find excellent use as anchoring agents for natural and synthetic filaments films and artificial leather. They may also be used to finish and impregnate or coat by surface modification or other manipulative techniques, a number of industrial and commercial articles.
While the invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses or adaptations of the invention following, in general, the principles of the invention and including such departures as come within known or customary practice in the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as fall within the scope of the invention and the limits of the appended claims.
The invention is hereby claimed as follows:
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Covers a new composition of matter comprising a stable N-(ω-monoalkylaminoalkyl) acrylamide or methacrylamide monomer characterized by the following structural formula: ##STR1## where R 1 and R 2 are hydrogen or methyl, R 3 is isopropyl or t-butyl and n is 2 or 3, with the proviso that when R 1 is hydrogen, R 3 is t-butyl. Also covers a method of preparing said monomer by condensing one mole of an acrylic or methacrylic compound with two moles of an appropriate amine to form an intermediate substituted amide, followed by heating said intermediate to split off one mole of reactant diamine leaving the desired substituted aminoalkyl acrylamide or acrylamide monomer.
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BACKGROUND OF THE INVENTION
There are various possible abnormal conditions or irregularities taking place in a sewing machine, such as thread breakage, stitch skipping or stitch leaving out, needle breakage, etc. Causes thinkable for each of those abnormal conditions are generally plural, so an operator is usually obliged to check all of imaginable causes for each abnormal condition, so as to solve the problem of such abnormal conditions. This checking operation of the existence of those causes of abnormal conditions has been an extremely tiresome and time consuming work, because of multifunction of the sewing machine and a variety of such causes in recent days. This kind of checking performed with reference to an instruction manual booklet creates a great burden for the operator, particularly so for a household operator who is not so familiar with machinery.
SUMMARY OF THE INVENTION
It is a primary object of this invention, which was made from such a background, to provide a device for vocally indicating causes of abnormal conditions in a sewing machine, which is capable of vocally indicating contents related to causes of a plurality of abnormal conditions imaginable to take place in the machine.
For achieving the above-mentioned object, a device for vocally indicating causes of abnormal conditions of a sewing machine in accordance with this invention is provided with a memory which stores plural groups of speech data to vocally indicate or display contents related to at least one cause of each of abnormal conditions or irregularities taking place in a sewing machine, whereby when any abnormal condition occurs in the sewing machine a voice signal corresponding thereto is designated so that the operator can perceive the content of the cause of the abnormal condition through the voice.
As causes of irregularities in the sewing machine are indicated to the operator concretely and vocally, all that the operator has to do is to check the machine according to the content indicated in voice. It makes the checking work simple and efficient, and particularly relieves the operator unfamiliar to machinery from the heavy burden of the sewing machine handling.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a general perspective view of a sewing machine in which a first embodiment of this invention is incorporated;
FIG. 2 is an enlarged view for showing the structure of a presser foot detector;
FIG. 3 is an enlarged view for showing the structure of a bobbin thread consumption detector;
FIGS. 4A and 4B is a block diagram for showing a circuit structure in the first embodiment;
FIGS. 5 to 9 are respectively a block diagram for showing particularly detailed structure of a pattern indication controlling circuit, a sewing state indication controlling circuit, a warning indication controlling circuit, a timing logic circuit, and a motor drive commanding circuit in FIG. 4;
FIG. 10 is a general perspective view of a sewing machine in which a second embodiment of this invention is incorporated;
FIG. 11 is an enlarged view for showing the general view of an abnormal condition indicating device;
FIG. 12 is a block diagram for showing a circuit structure in the second embodiment; and
FIG. 13 is a table for showing a memory map of a data memory.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to the appended drawings the first embodiment will be described hereunder.
On a bed 2 of a machine frame a bracket arm 4 is, as can be seen in FIG. 1, horizontally disposed, being retained at one end thereof by a standard 6 in a cantilever status. On the free end side of the bracket arm 4 a head 8 is formed, in which a needle bar 10 vertically reciprocable and laterally oscillatable due to a known reciprocation mechanism and an oscillation mechanism (neither is shown), and a presser bar 12 movable up-and-down by operation of an operator are disposed. To the lower end of the needle bar 10 and the presser bar 12 a needle 14 and a presser foot 16 are respectively attached as shown in FIG. 2. To this presser bar 12 a rack 18 is secured, and a pinion 22, on the tip of whose rotary shaft a rotatable potentiometer 20 is fixed, is firmly disposed in the head 8 so as to engage with the aforementioned rack 18. Position of the presser foot 16 can be thereby electrically detected.
On the bed 2 just beneath the needle bar 10 a throat plate 24 is disposed, and in the middle portion thereof a feed dog 26 is placed for imparting a feed movement to a workpiece controlled by a not-shown but well-known feed regulating mechanism. The feed dog 26 and the needle bar 10, which constitute the stitch forming instrumentalities, enable relative movement between the needle 14 and the workpiece so as to form a desired stitch pattern on the workpiece.
Beneath the throat plate 24 a known mechanism for detecting bobbin thread consumption amount is disposed within the bed 2. On either side of a bobbin case 30 accommodating a bobbin 28 therein, as shown in FIG. 3, an optical fiber 32 for light projecting and an optical fiber 34 for light receiving are secured face-to-face at their respective end faces 36, 38. And the bobbin case 30 is provided with an opening 40 positioned on a straight line linking both end faces 36, 38, so as to pass light emitted from the end face 36 to the end face 38 when the bobbin thread wound on a bobbin 28 is decreased. Numeral 42 designates a convex lens and numeral 44 an arm for fixing the bobbin 28.
On the front side at a lower portion of the head 8 returning to FIG. 1 a start-stop push button 46 as a manual means for starting and stopping a drive motor 192 as a drive means and also for generating warning voice, and a back stitching push button 48 for forming a back stitch are disposed. On the front side at a lower portion of the standard 6 a speech repeat push button 50 as a manual button operable to repeat voice outputting such as warning statement, a speech stop push button 52 for stopping the voice outputting, and a cause speech push button 54 for outputting a cause of an abnormal condition in the machine are disposed. Beneath these push buttons (50, 52, 54) a speaker 56 as a warning means for speaking warning statement is disposed. On the front side of the bracket arm 4 a pattern display panel 66, on which symbols respectively representing thirteen kinds of stitch patterns such as straight stitching 58, basting 60, bar tacking 62, buttonhole stitching 64, etc. are displayed, is fixed. Beneath each of those symbols a pattern selection push button 68 is disposed, thirteen in all, to be operated for selecting a desired one stitch pattern out of the plurality. On the right side of the pattern display panel 66 a speech interrupt switch 70 for stopping any other sound than the abnormal condition warning voice in the machine is disposed.
Electric structure in a sewing machine with the above-mentioned make-up will be described hereunder with reference to FIG. 4.
Terminals on one side of switches 72 of automatic return type which each is closed by depressing of the pattern selection push button 68 are commonly ground, while terminals on the other side are respectively connected to a plus source via resistors 74 and to NAND gates 78 via inverters 76. A terminal of the speech interrupt switch 70 is grounded, while the other terminal thereof is connected via a resistor 80 to a plus source and also to the NAND gates 78 as well as a NAND gate 82. Furthermore, one terminal of a switch 84 of automatic return type which is closed in response to depressing of the cause speech push button 54 is grounded, while the other terminal is connected via a resistor 86 to a plus source and also to the NAND gate 82 via an inverter 88. While, therefore, the speech interrupt switch 70 is open, depressing of the pattern selection push button 68 will cause one of the thirteen signals from PS1 to PS13 corresponding to the push button 68 depressed to be selectively supplied from the NAND gates 78 to a pattern indication controlling circuit 90 as an "L" level signal. When on the other hand the cause speech push button 54 is depressed while the speech interrupt switch 70 is open, a cause speech command SSP is supplied from the NAND gate 82 to a sewing state indication controlling circuit 92. While the speech interrupt switch 70 is closed, however, each gate of the NAND gates 78 and 82 is closed so as to prevent outputting any of the signals PS1-PS13 and the cause speech command SSP.
The pattern indication controlling circuit 90 is constructed as shown in the block diagram of FIG. 5. When any one of the signals PS1-PS13 is supplied to an encoder 94 a pattern code signal SM representing a selected stitch pattern is supplied to an address memory 96 and a known stitch data generator (not-shown) for positioning the needle bar 10 and a feed regulator. From the address memory 96 to input ports DA1 and DB1 of a multiplexor 100, supplied are a start address signal SA1 representing start address and an end address signal SB1 representing end address in a later described speech data memory 98 as a memory means for permanently storing speech data, wherein plural groups of corresponding speech data are stored for displaying stitch patterns represented by the supplied pattern code signal SM in the form of voice. When on the other hand the encoder 94 is supplied with any one of the signals PS1-PS13, it supplies in turn an operation signal SH of "L" level to a clock terminal CK of a flip-flop circuit 102. The circuit 102 becomes a set status by the supply of the operation signal SH so as to supply a port select signal SP3 of "H" level from an output terminal Q thereof to a port select terminal G1 of the multiplexor 100 and a later described timing logic circuit 104. This status of the flip-flop circuit 102 is maintained until a latch completion signal SC1 from the timing logic circuit 104 is supplied to a clear terminal CLR thereof.
The pattern indication controlling circuit 90 is therefore, for the purpose of displaying the selected stitch pattern by operation of the pattern selection push button 68 in the form of voice, to supply a corresponding start address signal SA1 and end address signal SB1 to the multiplexor 100.
The sewing state indication controlling circuit 92 has a made-up illustrated in the block diagram of FIG. 6. More particularly describing, when a cause speech command SSP is supplied to a clock terminal CK of a flip-flop circuit 106, the latter is turned to a set state for supplying a port select signal SP1 of "H" level from its output terminal Q to a port select terminal G2 of the multiplexor 100, the timing logic circuit 104, and a clock terminal CK of an address counter 108. This status of the flip-flop circuit 106 is maintained until a latch completion signal SC1 is supplied to a clear terminal CLR thereof. The address counter 108 counts the port select signals SP1 and then supplies a signal SK representing the count content thereof to an address memory 110, and the count content is turned to zero by resetting the counter 108. When however the count content reaches "6" by counting the signals SP1 it is returned again to "1". In the memory 110, for indicating or displaying a cause of an abnormal condition in the form of voice in response to a supplied signal SK, a start address signal SA2 representing a start address of the speech data memory 98 and an end address signal SB2 representing an end address of the same are supplied to input ports DA2 and DB2 of the multiplexor 100. Besides, the address counter 108 is supplied to a reset terminal RT thereof with a power on timing signal SRT, i.e., a pulse signal of "L" level, by way of an AND gate 112, and at the same time it is also supplied with a drive command SC2 from a later described motor drive commanding circuit 114 by way of a monostable multivibrator 116 and the AND circuit 112. The address counter 108 is thereby to be reset when at least either one of the power on timing signal SRT and the drive command SC2 is generated.
The sewing state indication controlling circuit 92 functions therefore, for displaying in voice the contents and causes of six kinds of irregular sewing states one after another in response to the operation of the cause speech push button 54, to supply a corresponding start address signal SA2 and end address signal SB2 to the multiplexor 100.
In the invented sewing machine an overload detector 118, a bobbin thread consumption detector 120 and a presser foot detector 122 as means for detecting occurrence of an abnormal condition which hinders normal stitch forming and generating a signal telling the detection thereof, are disposed.
The overload detector 118 for the drive motor 192 is provided with a known mechanism for detecting, while the drive command SC2 is being output from the motor drive commanding circuit 114, rotational state of the drive shaft and outputting a detection signal SDT1 if the number of rotation of the drive shaft has not reached a normal amount. Structure of the bobbin thread consumption detector 120 is composed of a mechanism illustrated in FIG. 3, a light source, and a light receiving element. When the light receiving element received light emitted from the light source via both optical fibers 32, 34, a detection signal SDT2 is output. The presser foot detector 122 includes a circuit which compares an output voltage of the potentiometer 20 corresponding to an actual height of the presser bar 12 shown in FIG. 2 with a predetermined reference voltage, and when the output voltage of the potentiometer 20 exceeds the reference voltage a detection signal SDT3 is output. All of those abnormal detection signals of "L" level, SDT1, SDT2, and SDT3 are respectively supplied to a warning indication controlling circuit 124 and the motor drive commanding circuit 114.
The warning indication controlling circuit 124, as means for actuating warning means in response to the operation of the foregoing manual means while abnormal condition is remaining, is constructed as shown in FIG. 7. The circuit 124 is provided with three flip-flop circuits 126, 128, and 130, wherein the latch completion signal SC1 is supplied to a respective clear terminal CLR thereof and a warning command SCK is supplied from the motor drive commanding circuit 114 to a respective clock terminal CK of the three flip-flop circuits 126, 128, and 130 by way of AND gates 131, 132, and 134. The detection signal SDT1 is respectively supplied via an inverter 133 and the AND gate 131 to a clock terminal CK of the flip-flop circuit 126, and via the AND gates 132 and 134 to clock terminals CK of the flip-flop circuits 128 and 130. The detection signal SDT2 is supplied via an inverter 136 and the AND gate 132 to a clock terminal CK of the flip-flop circuit 128, and via the AND gate 134 to a clock terminal CK of the flip-flop circuit 130. And the detection signal SDT3 is supplied via an inverter 138 and the AND gate 134 to a clock terminal CK of the flip-flop circuit 130. Output signals of "H" level representing set state of those flip-flop circuits 126, 128, and 130 are respectively supplied from an output terminal Q thereof to an OR gate 140 and an address memory 142. An output signal of the OR gate 140 is supplied as a port select signal SP2 to a port select terminal G3 of the multiplexor 100 and to the timing logic circuit 104. From the address memory 142, for displaying in voice an alarm respectively corresponding to the set state in the flip-flop circuits 126, 128, and 130, a start address signal SA3 representing a start address and an end address signal SB3 representing an end address in the speech data memory 98, where plural groups of speech data representing the alarms are stored, are supplied to input ports DA3 and DB3 of the multiplexor 100.
The warning indication controlling circuit 124 is therefore given a function, for the purpose of displaying the alarm contents corresponding to the detection signal SDT1, the detection signal SDT2 and the detection signal SDT3 in voice, to supply the start address signal SA3 and the end address signal SB3 to the multiplexor 100 when a warning command SCK is generated, and to allow priority to the detection signal SDT1 over other detection signals SDT2 and SDT3 and allow priority to the detection signal SDT2 over the detection signal SDT3 when all of these signals are generated at a time.
In the multiplexor 100, while the port select signal SP3 is being supplied to the port select terminal G1 thereof, the start address signal SA1 and the end address signal SB1, which are being supplied to the input ports DA1 and DB1, are output from output terminals QA and QB thereof to a start address latch 144 and an end address latch 146. While the port select signal SP1 is being supplied to the port select terminal G2 in a similar way, the start address signal SA2 and the end address signal SB2, which are being supplied to the input ports DA2 and DB2, are output. While further similarly the port select signal SP2 is being supplied to the port select terminal G3, the start address signal SA3 and the end address signal SB3 supplied to the input ports DA3 and DB3 are output.
In the start address latch 144 and the end address latch 146, when the load signal SL is supplied from the timing logic circuit 104, the signal supplied from the multiplexor 100 to the input terminals thereof is temporarily memorized, and the signals representing the memorized contents are respectively supplied to an address counter 148 and an input terminal DA of a later described comparator 150.
The timing logic circuit 104 is made up as shown in the block diagram of FIG. 8. There is a flip-flop circuit 152 provided therein, which receives a speech end signal SC3 from the comparator 150 at a clear terminal CLR thereof. The port select signal SP2 is supplied to a clock terminal CK of the flip-flop circuit 152 and a monostable multivibrator 154. The port select signals SP1 and SP3 are supplied via monostable multivibrators 156, 158 to an OR gate 160. An output signal of the OR gate 160 and an output signal of "H" level representing a reset state of the flip-flop 152 are supplied to an AND gate 162. An output signal from the AND gate 162 and an output signal from the monostable multivibrator 154 are supplied to an OR gate 164. An output signal from the OR gate 164 is supplied via a monostable multivibrator 166 and an inverter 167 to, as a load signal SL of "L" level, the start address latch 144 and the end address latch 146, and at the same time supplied via monostable multivibrators 166, 168, and 170 to, as a latch completion signal SC1 of "L" level, the pattern indication controlling circuit 90, the sewing state indication controlling circuit 92, the warning indication controlling circuit 124, and an AND gate 172. The timing logic circuit 104 functions therefore such that, when any one of the port select signals SP1, SP2, and SP3 is supplied a load signal SL is output after a certain time span respectively corresponding to output pulse width of each of monostable multivibrators 156, 154, and 158, and when the output of the load signal SL is finished a latch completion signal SC1 is output after a certain time span corresponding to output pulse width of a monostable multivibrator 168, and furthermore when the port select signal SP2 is supplied first, outputting of load signals SL and latch completion signals SC1 based on the later supplied port select signals SP3, SP1 is blocked until the vocal indication of warning is finished.
The motor drive commanding circuit 114, as means for inhibiting drive means from driving the stitch forming instrumentalities regardless of the operation of the foregoing manual means while detection signal is generated, is made up as shown in FIG. 9. From a switch 174 which is closed in response to depressing of the start-stop push button 46 of automatic return type an operation signal SMC of "L" level is suppplied via a monostable multivibrator 176 to an AND gate 178 and an exclusive OR gate 180, while the detection signal SDT1 and the detection signal SDT2 are respectively supplied to the AND gate 178 and an AND gate 182 on one hand, the detection signal SDT3 is supplied on the other hand by way of a tristate buffer 185, which is conducted when an output terminal Q of a flip-flop circuit 184 externally connected for being operable as a so-called binary circuit is at "L" level state, to the AND gate 178. An output signal of the AND gate 178 is supplied to a clock terminal CK of the flip-flop circuit 184 and the exclusive OR gate 180, and an output signal from the exclusive OR gate 180 is supplied as the warning command SCK to the warning indication controlling circuit 124. And the drive command SC2 of "H" level which represents a set state of the flip-flop circuit 184 is supplied from its output terminal Q to the motor drive controlling circuit 186 and the overload detector 118. An output signal of the AND gate 182 is supplied together with the power on timing signal SRT via a tristate buffer 188, which is conducted when an output terminal Q of the flip-flop circuit 184 is at "L" level state, to an AND gate 190, and an output signal thereof is supplied in turn to a clear terminal CLR of the flip-flop circuit 184.
The motor drive commanding circuit 114 outputs, while none of the detection signal SDT1, the detection signal SDT2, or the detection signal SDT3 is supplied (that is to say a case all being of "H" level), alternately the drive command SC2 of "H" level and the stop command of "L" level at each inputting of the operation signal SMC; it outputs on the contrary, while any one of the detection signals SDT1, SDT2, and SDT3 is being supplied, the warning command SCK in response to inputting of the operation signal SMC and withdraws the output of the drive command SC2. If the detection signal SDT1 or the detection signal SDT2 is being output to the motor drive commanding circuit 114 the output of the drive command SC2 is ceased.
The above-mentioned motor drive controlling circuit 186 is a well known one which supplies power to the drive motor 192, while the drive command SC2 is being supplied, for driving the same at a preset speed.
As to a switch 194, one terminal thereof is grounded while the other is connected via a resistor 196 to a plus source as well as to a monostable multivibrator 198, whose output signal is supplied together with the latch completion signal SC1 to the AND gate 172. An output signal of the AND gate 172 is supplied to a clock terminal CK of a flip-flop circuit 200 and to a load terminal LD of the address counter 148.
One terminal of a switch 202, which is closed by depressing of the speech stop push button 52, is grounded while the other is connected via a resistor 204 to a plus source as well as to a monostable multivibrator 206, whose output signal is supplied together with the speech end signal SC3 to an AND gate 208. An output signal of the AND gate 208 is supplied to a clear terminal CLR of the flip-flop circuit 200. An output signal of "H" level representing a set state of the flip-flop circuit 200 is supplied together with a clock pulse CP output from an oscillator 210 to an AND gate 212, whose output signal is supplied to a clock terminal CK of the address counter 148.
When therefore the speech repeat push button 50 is depressed or the latch completion signal SC1 is generated the address counter 148 is loaded with an output signal of the start address latch 144, that is a start address signal, and a clock pulse CP is supplied to the clock terminal CK of the address counter 148, because the flip-flop circuit 200 is then at a set state. When however the speech stop push button 52 is depressed or the speech end signal SC3 is generated the flip-flop circuit 200 is cleared and the clock pulse CP is blocked by the AND circuit 212 thereby not to reach the address counter 148.
When the address counter 148 is supplied at its load terminal LD with a signal, an output signal of the start address latch 144 is loaded there. A value represented by this signal is added, by the clock pulse CP supplied to the input terminal thereof, through calculation, and a signal representing the calculated result is supplied to the speech data memory 98 and the input terminal DB of the comparator 150. This signal representing calculated contents functions as the address signal SD which designates one after another the speech data stored in the speech data memory 98.
In the comparator 150, when an end address signal supplied to an input terminal DA thereof is agreed with an address signal SD supplied to an input terminal DB thereof, a speech end signal SC3 of "L" level is supplied from an output terminal QD thereof to the timing logic circuit 104, and at the same time it is supplied via monostable multivibrators 214, 216 to a reset terminal RT of the address counter 148.
In the speech data memory 98 plural groups of speech data SO for vocal indication, as those listed in TABLE I as an example, are stored, and when an address signal SD is applied to the speech data memory 98 the speech data SO designated by the address signal SD is supplied to a D/A converter 218. As the speech data SO is a codified digital signal, it is converted in the D/A converter 218 to a voltage value which the speech data SO represents for being output. And a voice signal SG is approximately made by synthesizing the output signals from the D/A converter 218 represented by the corresponding group of speech data SO. This voice signal SG is supplied via an amplifier 220 to the speaker 56 for being vocally indicated therefrom. The speech data memory 98 and the D/A converter 218 constitute in this way a voice signal generator.
In the above description no concrete data or description about the digital data in the speech data memory 98 is provided, because the technology concerned to the digital data for the speech data is already known.
TABLE I______________________________________No. Statements of the Vocal Indication______________________________________1 "Straight Stitch. Use presser foot J."2 "Basting. Use presser foot J, and lower the feed dog."3 "Bar tacking. Use presser foot A, and lower the switch lever."4 "Buttonhole stitching. Use presser foot A, and lower the switch lever."5 "Don't feed the workpiece. Is not the feed dog lowered?"6 "Is not the stitch length set at zero?"7 "Is not the pressure adjusting lever set at zero?"8 "Upper thread broken. Is not the way of thread stretching wrong?"9 "Is not the thread tension too strong?"10 "Is the needle attached rightly?"11 "The machine has been locked. Read the instruction manual again."12 "Bobbin thread is running short."13 "Lower the presser foot."______________________________________
OPERATION OF THE EMBODIMENT
Operation of the embodiment will be described hereunder. When power is ON by a not-shown switch the circuit in FIG. 4 is energized. By virtue of a power on timing signal SRT the address counter 108 is reset and the flip-flop circuit 200 is cleared. At the same time the other flip-flop circuits 102, 106, 126, 128, 130, 152, and 184 are all cleared through a not-shown circuit.
When one of the stitch patterns, for example a straight stitching 58, is selected as desired by operating one of the pattern selection push buttons 68, a signal PS1 corresponding to the straight stitching is supplied to the pattern indication controlling circuit 90. A start address signal SA1, an end address signal SB1, and a port select signal SP3 for vocally indicating the straight stitching from the pattern indication controlling circuit 90 are thereby output. These start address signal SA1 and end address signal SB1 are supplied via the multiplexor 100 to the start address latch 144 and the end address latch 146. On the other hand a load signal SL is output from the timing logic circuit 104, after a certain time span from the generation of the port select signal SP3, causing the start address signal SA1 and the end address signal SB1 to be loaded in the start address latch 144 and the end address latch 146, and then to be supplied to the address counter 148 and the comparator 150. When a certain predetermined time has lapsed after the generation of the load signal SL, a latch completion signal SC1 is output from the timing logic circuit 104. The flip-flop circuit 200 is thereby set, and the start address signal SA1 is loaded in the address counter 148. And in the pattern indication controlling circuit 90 the flip-flop circuit 102 is cleared for restraining the output of the port select signal SP3. When the flip-flop circuit 200 is set the clock pulse CP is supplied via the AND gate 212 to the address counter 148, which adds the clock pulses CP one after another on the start address signal SA1 for outputting the count content as an address signal SD to the speech data memory 98 and the comparator 150. Speech data SO designated by the address signal SD are supplied one after another from the speech data memory 98 to the D/A converter 218 for being output therefrom as the voice signal SG. Vocal indication of the statement of No. 1 of TABLE I is started in this way as an output from the speaker 56. When the vocal indication is finished the content of the address signal SD comes to coincide with the end address signal SB1, causing the comparator 150 to output the speech end signal SC3. This results in clearance of the flip-flop circuit 200, followed by blocking the supply of the clock pulse CP with the AND gate 212, and resetting of the address counter 148 so as to make its content equal to zero, after a certain prdetermined time span from the generation of the speech end signal SC3.
When other stitch patterns, such as basting 60, bar tacking 62, or buttonhole stitching 64, are selected by operation of the pattern selection push button 68 a similar operation to the above will be executed respectively so as to vocally indicate the statements in TABLE I, No. 2, No. 3 and No. 4 in that order.
When the start-stop push button 46 is depressed in the above-mentioned status, the flip-flop circuit 184 is made a set state due to the operation signal SMC which is supplied by way of the monostable multivibrator 176 and the AND gate 178, and the drive command SC2 is output from the flip-flop circuit 184. The drive motor 192 is thereby driven, followed by driving of a not-shown needle bar oscillation mechanism and feed regulation mechanism. A desired stitch pattern selected by the depression of the pattern selection push button 68 can be formed thereby on the workpiece. If the start-stop push button 46 is depressed again the flip-flop circuit 184 is reversed so as to block the output of the drive command SC2, with a result of halting of the drive motor 192.
In the course of the above-mentioned sewing operation causes of various accidental abnormal conditions, for example malfeeding of the workpiece, upper thread breakage, etc. are indicated vocally by depressing of the cause speech push button 54. When this push button is depressed the flip-flop circuit 106 is placed under a set state due to a cause speech command SSP for supplying the port select signal SP1 from the output terminal Q thereof to the address counter 108, the multiplexer 100, and the timing logic circuit 104. In the address counter 108 the port select signal SP1 is counted until the content thereof becomes "1" before the signal SK representing the resultant content is supplied to the address memory 110, from which a start address signal SA2 and an end address signal SB2 corresponding to the signal SK are output for being supplied in turn via the multiplexor 100 to the start address latch 144 and the end address latch 146. From the timing logic circuit 104, on the other hand, a load signal SL and a latch completion signal SC1 corresponding to the generation of the port select signal SP1 are output in the same way to the above so as to produce a series of vocal indications from the speaker 56 in respect of the statement standing in TABLE I as No. 5. The flip-flop circuit 106 is cleared by the latch completion signal SC1. Re-depressing of the cause speech push button 54 at this time the counted content of the address counter 108 becomes "2" for performing a series of the vocal indications of the No. 6 statement of TABLE I from the speaker 56. Afterwards at each depressing of the cause speech push button 54 the vocal indications from No. 7 to No. 10 of TABLE I are performed one by one, and further depressing of the cause speech push button 54 will cause a vocal re-indication of No. 5 of TABLE I. The operator is allowed therefore to investigate various causes of irregularities without the trouble of consulting the instruction manual for the machine.
The above described operation of the pattern selection push button 68 and the cause speech push button 54 are concerned to a case wherein the speech interrupt switch 70 is open. When this speech interrupt switch 70 is closed, on the contrary, the NAND gates 78, 82 will restrain the output of their signals PS1-PS13 and the cause speech command SSP. In this case, therefore, generation of operation commanding voice signal is ceased, while generation of cause warning voice signal is permitted, so as to stop the vocal indication representing the contents of pattern selection operation and the causes of irregularities of sewing state in the machine. Skilled operators are thereby allowed release from troubles of unnecessary vocal indications by means of only operating the speech interrupt switch 70.
When the start-stop push button 46 is depressed, if any one of the detection signals SDT1, SDT2, or SDT3 is being in generation, an operation signal SMC which should be supplied to the flip-flop circuit 184 is blocked by the AND circuit 178. The flip-flop circuit 184 is not brought to a set state, with a result of restraining the output of the drive command SC2 therefrom. It means that the AND circuit 178 is a prohibiting circuit for preventing the start of stitch forming operation while any of the detection signals SDT1, SDT2, or SDT3 is being generated. As one input terminal of the exclusive OR gate 180 is of "H" level and the other is of "L" level, a warning command SCK therefrom is supplied to the warning indication controlling circuit 124. If for example a detection signal SDT1 is being generated in the warning indication controlling circuit 124, at this time, the flip-flop circuit 126 is to be brought to a set state, which will cause an output signal representing the set state thereof to be supplied via the OR gate 140 as a port select signal SP2 to the multiplexor 100 and the timing logic circuit 104, and further to the address memory 142. From this address memory 142 a start address signal SA3 and an end address signal SB3, which are corresponding to the detection signal SDT1, are ouput for being supplied via the multiplexor 100 to the start address latch 144 and the end address latch 146. In the timing logic circuit 104, after a certain predetermined time span from the supplying of a port select signal SP2, a load signal SL is output in a similar way to the above. After a certain predetermined time span from the output of the load signal SL a latch completion signal SC1 is output, and the flip-flop circuit 152 is placed at a set state. Even if, under this condition, other port selct signal SP1 or SP3 is supplied, a load signal SL and a latch completion signal SC1 based on the signal SP1 or SP3 can not be output by being blocked by the AND gate 162. In other words, the flip-flop circuit 152 and the AND gate 162 make the vocal indication of warning finish in preference to the vocal indication of causes of irregularities in respect of stitch patterns and sewing state. Vocal indication of No. 11 of TABLE I is performed thereafter in the same manner as above-mentioned. Depressing operation of the start-stop push button 46 while the detection signal SDT2 is being generated causes the supply of a warning command SCK from the motor drive commanding circuit 114 to the warning indication controlling circuit 124 according to a similar operation stated above. In this warning indication controlling circuit 124 vocal indication of No. 12 of TABLE I is performed after the flip-flop circuit 128 is placed at a set state according to a similar operation stated above. Depressing operation of the start-stop push button 46 while the detection signal SDT3 is being generated similarly brings the flip-flop circuit 130 to a set state for performing vocal indication of No. 13 of TABLE I.
When the detection signal SDT1 should be generated in lapping with the detection signal SDT2 or the detection signal SDT3, the AND gate 131 allows in the warning indication controlling circuit 124 only the flip-flop circuit 126 to be placed at a set state, and the AND gates 132, 134 block the flip-flops 128, 130 to be placed at a set state, for preferentially performing vocal indication of No. 11 of TABLE I. If lapped generation of the detection signal SDT2 and the detection signal SDT3 should occur the blocking of the AND gate 134 similarly allows only the flip-flop circuit 128 to be placed at a set state for performing vocal indication of No. 12 of TABLE I.
When the detection signal SDT1 or the detection signal SDT2 is generated while the drive motor 192 is in rotation, either one of the two is supplied, in the motor drive commanding circuit 114, to the flip-flop circuit 184 by way of the AND gate 182, the tristate buffer 188, and the AND gate 190. The flip-flop circuit 184 is thereby cleared to automatically stop the drive motor 192.
Even when the start-stop push button 46 is operated while the machine is in an abnormal condition, vocal warning is made in parallel with halting of rotation of the drive motor 192 in the above-mentioned manner, which enables prevention of continuing of machine operation under an abnormal condition. It even allows to take necessary steps for remedying the irregularities in advance. Furthermore, the vocal warning can surely be performed without being hindered by other pattern indication and sewing state indication, and an important vocal warning is given preference in indication to others when plural abnormal conditions take place in lapping. It allows proper treatments to be taken speedily and surely.
When the operator has missed in hearing contents of vocal indication or left something unheard, for example in No. 1 of TABLE I, all that he/she has to do is to depress the speech repeat push button 50 to reproduce the indication. When the speech repeat push button 50 is depressed an output signal of "L" level from the monostable multivibrator 198 is supplied via the AND gate 172 to the flip-flop circuit 200 and the address counter 148. The start address signal SA1 which is latched at the start address latch 144 for the vocal indication is loaded in the address counter 148. At the same time the flip-flop circuit 200 is placed at a set state, and a clock pulse CP is supplied from the oscillator 210 to the address counter 148 by way of the AND gate 212. According to a similar operation the vocal indication of the matter shown in No. 1 of TABLE I is to be repeated.
In this way the operator is allowed, even when he/she accidentally missed in hearing a vocal indication, to repeat it at need so as to accurately or surely catch the contents thereof.
When a vocal indication, for example No. 1 of TABLE I, is started, a skilled operator may be well aware of the second half of the content to be indicated, i.e., what kind of presser foot should be used. In such a case only the vocal indication of a stitch pattern selected, for the purpose of making sure what kind pattern has been selected, is sufficient, and in the half way of the vocal indication the speech stop push button 52 is operated. This operation causes an output signal of "L" level from the monostable multivibrator 206 to be supplied via the AND gate 208 to the flip-flop circuit 200. The flip-flop circuit 200 is thereby cleared so as to block the clock pulse CP which has been supplied from the oscillator 210 to the address counter 148 at the AND gate 212. Counting operation in the address counter 148 is therefore stopped to restrain the later vocal indication.
The vocal indication can thus be interrupted according to the necessity of the operator, so a skilled operator can be released of botheration of unnecessary vocal indication so as to start the sewing operation as early as he/she desires.
In the first embodiment described above, the address counter 148, the comparator 150, the monostable multivibrators 214, 216 and the D/A converter 218 constitute the voice synthesizer 222 as means for controlling memory means as shown in FIG. 4, and speech data stored in the speech data memory 98 are synthesized into voice according the PCM system, i.e., Pulse Code Modulation system. However, another type of voice synthesizing, for example, PARCOR, i.e., Partial Auto Correlation system is also permissible, wherein capacity of memory can be reduced to a great extent. In such a case, as voice synthesizer 222, HD 38880, an LSI of HITACHI SEISAKUSHO, LTD. (Japan) and TMCO 280, an LSI of TEXAS INSTRUMENT CORP. (U.S.A.) all well known as suitable.
In the circuit structure of FIG. 4 a data processing circuit 224 is composed of the pattern indication controlling circuit 90, the sewing state indication controlling circuit 92, the warning indication controlling circuit 124, the timing logic circuit 104, the motor drive commanding circuit 114, the multiplexor 100, the flip-flop circuit 200, the AND gates 78, 82, 172, 208, 212, the inverters 76, 88 and the monostable multivibrators 198, 206. This data processing circuit 224 may be constituted of a so-called microcomputer. In such a case, the start address latch 144 and the end address latch 146 may be generally constituted of a random access memory (RAM) and the speech data memory 98 is constituted of a read only memory (ROM).
Hereunder a second embodiment will be described with reference to the drawings.
In this embodiment only function of vocal indication is respect of causes of abnormal conditions or irregularities is imparted, omitting other functions of vocal indication given to the first embodiment. In the drawings related, identical parts and portions as those in the first embodiment are allotted the same signs and numerals.
As can be seen in FIG. 10, the back stitching push button 48, the speech repeat push button 50, the speech stop push button 52, and the speech interrupt switch 70 are omitted, and an abnormal condition indicating device 226 provided with five push buttons 228, 230, 232, 234, and 236 as a manual means respectively operable to pick up each causes of abnormal conditions in sewing machine is installed in place of the cause speech push button 54 on the front side at a lower portion of the standard 6. The above-mentioned abnormal condition indicating device 226 further includes a display panel 238 which displys five kinds of abnormal conditions, that is to say "lack of workpiece feeding", "upper thread broken", "bobbin thread broken", "stitch skipping" and "needle broken", correspondingly to the five push buttons.
In the machine frame illustrated in FIG. 10 a circuit illustrated in FIG. 12 is contained.
The five push buttons 228, 230, 232, 234, and 236 are respectively corresponding to five switches 270-274, all of the those being connected to an encoder 240. When the switches 270-274 are closed respectively by depressing of each corresponding push button 228, 230, 232, 234, or 236, the encoder 240 outputs an abnormal condition code signal SAN, representing an abnormal condition corresponding to a depressed push button, and an operation signal SP11 representing the depressing of the push button.
The abnormal condition code signal SAN is supplied to a group address memory 242 and a group discrimination 244, and the operation signal SP11 is supplied to a clock terminal CK of a sentence address counter 246, an input terminal LD of a word address counter 248, and a clock terminal CK of a flip-flop circuit 249.
In a data memory 250 as a memory means for permanently storing plural groups of speech data, speech data SO for vocally indicating statements listed in TABLE II are stored. Those speech data SO are divided into five groups, as shown in the memory map in FIG. 13, i.e., from VA to VE, corresponding to five kinds of abnormal conditions (irregularities) such as, "lack of workpiece feeding", "upper thread broken", "bobbin thread broken", "stitch skipping" and "needle broken". The speech data SO are subdivided in each group into sub-groups corresponding to statements listed in TABLE II. For example, in a group VA indicating the abnormal condition of "lack of workpiece" there are three sub-groups Va-Vc of speech data SO corresponding to the three messages in TABLE II.
TABLE II______________________________________Irregularities Statements______________________________________lack of work- "Is not the feed dog lowered?"piece feeding "Is not the stitch length set at zero?" "Is not the pressure adjusting lever set at zero?"upper thread "Is not the way of stretching of thebroken upper thread wrong?" "Is not the thread tension too strong?" "Is the needle attached rightly?"bobbin thread "Is not the thread tension too strong?"broken "Is not the way of stretching of the bobbin thread wrong,"stitch "Is not the way of thread stretchingskipping wrong?" "Is the needle suitable for the work- piece and the thread attached rightly?"needle "Is the needle suitable for the work-broken piece and the thread attached rightly?" "Is not the thread stretched too strongly while being in a sewing operation?"______________________________________
Returning to FIG. 12, in the group address memory 242 each start address and end address of each group VA-VE of speech data SO stored in a speech data memory 250 are memorized, and start address signal GF and end address signal GE respectively representing a start address and an end address of groups corresponding to the contents of the input abnormal condition code signal SAN are respectively supplied to a latch 252.
In a group discrimination 244 contents of the previous abnormal condition code signal SAN output from the encoder 240 due to the abnormal condition indicating operation are to be memorized. When the contents of the input abnormal condition code signal SAN is unidentical with the content of the previous abnormal condition code signsl SAN a group change signal SP14 is output to an input terminal LD of the latch 252 and also to an input terminal CL of the sentence address counter 246 via an OR gate 254.
In the latch 252 the start address signal GF and the end address signal GE are, based on the group change signal SP14 supplied to the input terminal LD of the latch 252, temporarily memorized, and the start address signal GF and the end address signal GE as the contents of this memory are output for being applied to a sentence address memory 256 and a comparator 258. A sentence address counter 246 is provided with a function of clearance so as to clear what is memorized due to receiving of a signal at its input terminal CL. When the operation signals SP11 supplied to the input terminal CK thereof are counted, the counted content is output to be supplied to the sentence address memory 256 as a sentence number code signal SS. The sentence number code signal SS is used to designate one sub-group among the plural sub-groups of speech data SO respectively concerning causes of the corresponding abnormal condition, within each group VA-VE of the speech data SO memorized in the data memory 250.
In the sentence address memory 256, the start address and the end address of each of the sub-groups contained in each of the groups VA-VE of the speech data SO stored in the speech data memory 250 are memorized. And a sub-group of the speech data stored in the speech data memory 250 is specifically designated by the start address signal GF and the sentence number code signal SS. A sentence start address signal SF and a sentence end address signal SE, representing respectively the start address and the end address of that specified sub-group, are supplied to the word address counter 248 and a comparator 262.
In the word address counter 248, the signal SP11 applied to an input terminal LD thereof causes content of a sentence address signal SF to be loaded, so as to calculate by adding to the loaded content clock pulses CP supplied from an oscillator 264 via an AND gate 266 to a clock terminal CK thereof. The calculated content as an address signal AD is supplied one by one to the speech data memory 250, the comparator 258, and the comparator 262.
In the comparator 262, content of the sentence end address signal SE supplied to an input terminal DA thereof and content of the address signal AD supplied to an input terminal DB thereof are compared for supplying, when both contents are agreed, a sentence end signal SP12 to an input terminal CL of the flip-flop 249. Similarly in the comparator 258, when content of the end address signal GE supplied to an input terminal DA thereof and content of the address signal AD supplied to an input terminal DB thereof are agreed in comparison, a group end signal SP13 is supplied therefrom via the OR gate 254 to an input terminal CL of the sentence address counter 246.
The flip-flop circuit 249 is, by an operation signal SP11 input to a clock terminal CK thereof, brought to set state, and reset by a sentence end signal SP12 input to an input terminal CL thereof. As an output signal representing the set state is output from an output terminal Q thereof to an AND gate 266, a clock pulse CP is supplied to the word address counter 248 while the flip-flop circuit 249 is in set state.
In the speech data memory 250, speech data SO stored at a designated storage location by an input address signal AD are supplied one after another to a drive circuit 268. In other words, the above-mentioned circuit, which supplies the address signal AD to the speech data memory 250 in response to an operation of the abnormal condition indication device 226 which designates the abnormal condition, selects from among speech data stored in the speech data memory 250 a desired speech data group and also a speech data sub-group for generating them from the speech data memory 250 as outputs. It can therefore be said that the above-mentioned circuit constitute in fact a speech data selecting device.
In the drive circuit 268, consecutively input speech data SO are, in a similar manner as in the first embodiment, converted into voltage signals for being supplied, after having been electrically amplified as voice signals SG, to the speaker 56. The speaker 56 vocally indicates statements corresponding to the voice signals SG.
For vocally indicating the statements in TABLE II, the voice signal SG is approximately formed by synthesizing a series of input speech data SO in the drive circuit 268 which functions as a voice synthesizer. For this voice synthesizing either the PCM, Pulse Code Modulation, and PARCOR, Partial Auto Correlation, is employable.
Operation mode of this embodiment will be described hereunder.
When power is on by a not-shown switch, the flip-flop circuit 249 is reset for putting the machine in a ready status to a stitch forming operation.
When any abnormal condition or irregularity occurs in the machine to hinder smooth operation thereof, for example an imperfect feeding of a workpiece, the operator depresses the push button 228 for designating the abnormal condition.
The depressing of the push button 228 causes an abnormal condition code signal SAN representing the abnormal condition of "lack of workpiece feeding" to be supplied to the group address memory 242, and a start address signal GF and an end address signal GE respectively representing the start address and the end address of the speech data group VA corresponding to the designated abnormal condition are thereby supplied to the latch 252. At the same time the abnormal condition code signal SAN is supplied to the group discrimination 244. When an irregularity represented by the previous abnormal condition code signal SAN is unidentical with the irregularity "lack of workpiece feeding" of this time, a group change signal SP14 is supplied to the latch 252 so as to render the start address signal GF and the end address signal GE to be temporarily memorized therein, and the latched signals GF, GE are supplied to the sentence address memory 256 and the comparator 258.
On the other hand, the sentence address counter 246 is supplied, in response to the depressing of the push button 228, with an operation signal SP11 representing the depressing operation, and also with a group change signal SP14 by way of the OR gate 254 so as to make the calculation content zero. As a result of the above operation, based on a start address signal GF representing the start address of the speech data group VA corresponding to the irregularity of the "lack of workpiece feeding" and the sentence number code signal SS representing the zero of the calculation content, a sentence start address signal SF and a sentence end address signal SE, which respectively represent the start address and the end address of the first sub-group Va in the speech data group VA, are supplied from the sentence address memory 256 to the word address counter 248 and the comparator 262.
Releasing of the push button 228 at this condition will take place the flip-flop circuit 249, which is operated by the falling of the operation signal SP11, at a set state to supply a clock pulse CP to the word address counter 248, where content of the sentence start address signal SF is simultaneously loaded. In the word address counter 248 calculation of adding clock pulses CP on the content of the sentence start address signal SF is therefore performed, and the calculated content as the address signal AD is supplied one by one to the speech data memory 250, and the comparators 262, 258.
Therefore, speech data SO in one sub-group Va are sequentially supplied from the speech data memory 250 to the drive circuit 268, so as to make vocal indication, through the speaker 56, of the statement "Is not the feed dog lowered?" This is the first vocal indication expressing a cause of the irregularity "lack of workpiece feeding". At the termination of such a vocal indication the content of the address signal AD is agreed with the content of the sentence end address signal SE, so a sentence end signal SP12 is supplied from the comparator 262 to the flip-flop circuit 249 so as to reset the same. It results in interruption of supplying of a clock pulse CP by the action of the AND gate 266, followed by interruption of calculating operation in the word address counter 248.
Re-depressing of the push button 228 causes an abnormal condition code signal SAN of the same content to be supplied to the group discrimination 244 so as to restrain outputting of the group change signal SP14. The sentence address counter 246 counts therefore the number of operation signals SP11. The count content "1" representing a sentence number code signal SS is supplied to the sentence address memory 256 as a result.
In the sentence address memory 256, a sentence start address signal SF and a sentence end address SE representing the start address and the end address of the second sub-group Vb are output, based on the start address signal GF and the sentence number code signal SS.
As a result of the above operation the vocal indication of the statement "Is not the stitch length set at zero?" is carried out in the same manner as the previous description. This is the second vocal indication expressing a second cause of the irregularity "lack of workpiece feeding".
Further depressing of the push button 228 makes the sentence address counter 246 continue counting of the operation signals SP11, and the count content "2" as a sentence number code signal SS is supplied to the sentence address memory 256 for causing a sentence start address signal SF and a sentence end address signal SE respectively representing the start address and the end address of the third sub-group Vc to be output from the sentence address memory 256.
Vocal indication of "Is not the pressure adjusting lever set at zero?" will take place, as a result of the above, in the wake of the previous operation. This is the third vocal indication expressing a third cause of the irregularity "lack of workpiece feeding".
At the termination of the third vocal indication the content of the address signal AD is agreed with the content of the sentence end address signal SE and the end address signal GE, so a sentence end signal SP12 is output from the comparator 262 so as to reset the flip-flop circuit 249, and a group end signal SP13 is output from the comparator 258 to clear the count content of the sentence address counter 246. It means that the operational condition of the circuit shown in FIG. 12 is returned to a condition immediately before the initial depressing of the push button 228.
The above description was all concerned to depressing operation of the push button 228 related to the irregularity of "lack of workpiece feeding" in the machine. As to another case wherein any one of the other push buttons 230, 232, 234, or 236 is depressed in relation to the other irregularities, the previous description is similarly applicable. The remaining statements in TABLE II are respectively indicated in voice against the corresponding irregularity of the machine.
In the above second embodiment the push buttons 228, 230, 232, 234, and 236 are commonly used as the manual means for designating the irregularities in the machine and the manual means for commanding the vocal indication of causes of the irregularities. However, the latter manual means for indicating the causes in voice may be separately installed. In this instance, the manual means for commanding the vocal indication may be designed such that the then operation signal can replace the operation signal SP11 output from the encoder 240 in FIG. 12. It is also another alternative that means for controlling memory means encircled by a two-dot-chain line in FIG. 12 is replaced by a microcomputer, partially or wholly, for the purpose of miniaturization of the circuit in FIG. 12.
In the above second embodiment the operator is to press a push button, after the operator recognized an irregularity in the machine, corresponding to the kind of the irregularity. However, if the machine is provided with a plurality of detectors within the machine frame for detecting each of the irregularities, an optical indicating device disposed for designating a push button to be depressed among those 228-236 may optically designate, by means of letting it operate under a detection signal from the detectors, a push button corresponding to the happened irregularity.
All of the above description is concerned only to a couple of embodiments of this invention. It goes without saying that modifications and alterations can be made by those skilled in the art without departing from the spirit and scope of the invention.
As described in detail in the above, when an abnormal condition has happened in a sewing machine, all that the operator has to do is to depress a push button which designates the abnormal condition. Then causes imaginable for the abnormal condition are vocally indicated one after another, so the operator can check the causes according to what was vocally indicated, without consulting the instruction manual each time, which enables him/her to easily and efficiently solve the problem of the irregularity. It not only releases the operator from consulting the instrucion manual for each case, but also release an operator unfamiliar with machinery from the hardness of finding out causes of irregularities. Another merit resides in preventing the operator from mishearing or leaving unheard the content of the vocal indication, because the indication is made one by one at each depressing of the push button.
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A diagnostic table which stores possible causes of certain abnormal conditions is accessed by corresponding push buttons for sequential vocalization by a sewing machine system, thereby helping the operator check the machine.
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TECHNICAL FIELD
[0001] The present invention relates generally to estimating and controlling driveline torque in a continuously variable hydro-mechanical transmission, and more particularly, to a method that does so using pressure data and other metrics of the hydrostatic unit, in lieu of actual driveline torque data.
BACKGROUND ART
[0002] Continuously variable hydro-mechanical transmissions are used in a variety of work machines, including for construction, earth moving, forestry, and agriculture. Reference in this regard, Weeramantry, U.S. Pat. No. 7,063,638 B2, issued Jun. 20, 2006, which discloses a representative continuously variable hydro-mechanical transmission. Typically, a continuously variable hydro-mechanical transmission will have a hydrostatic unit as one power input to a planetary gear set, and a mechanical connection to the engine of the machine as a second power input, with the output of the planetary connected via a clutch to one or more final gear reductions in connection with a load, e.g., the wheels, tracks or other drivers of the machine.
[0003] An advantage of continuously variable hydro-mechanical transmissions is that they can provide a large speed range seamlessly. As another advantage, continuously variable hydro-mechanical transmissions are typically capable of lower gear ratios than transmissions with fixed gear ratios. As result, the engine and transmission combination can produce higher torques to the wheels, tracks, or other drivers, which is beneficial as it enables the work machine to pull harder. However, the higher torque can damage mechanical aspects of the transmission, particularly, the final gear reduction or output member of the driveline of the transmission. Typically, it is been found that damage to the final gear reduction or output member will occur if the torque is too high for a prolonged period of time.
[0004] In agricultural applications, such as wherein a work vehicle such as when a tractor is pulling a large implement, or a deep subsurface tillage tool, a heavy wagon or cart, or the like, potentially damaging continuous high torque loads can be placed on the transmission driveline. Damage from intermittent or incidental high loads can also result from ground conditions, e.g., inclines, ruts, deep furrows, wet spots, transitions onto roads, and the like, when driving, and from contact with denser soil, buried objects such as stones or rock formations, large roots, and the like when doing subsurface tillage.
[0005] To avoid such damage, one alternative is to limit engine torque output. However, often the engine supplies power to other systems of the work machine, e.g., auxiliary hydraulics, power take offs, and the like, and it can be problematic to reduce toque output to those systems also. The torque loads of these other systems typically vary and may be unknown, making accurately adjusting engine torque difficult. As another alternative, the transmission torque can be determined using an estimate of the engine torque and subtracting the torque loads of the other systems, or using maximum torque values for those systems, but this is often more complex, more costly and less accurate than desired.
[0006] Thus, what is sought is a manner of determining driveline torque of a continuously variable hydro-mechanical transmission of a work machine, particularly in the vulnerable final gear reduction of the driveline, and limiting the torque for preventing damage to the transmission, without the shortcomings set forth above.
SUMMARY OF THE INVENTION
[0007] What is disclosed is a method of estimating driveline torque of a continuously variable hydro-mechanical transmission of a work machine, particularly in the final gear reduction or output member, and limiting the torque for preventing damage to the transmission, without the shortcomings set forth above.
[0008] During operation of a continuously variable hydro-mechanical transmission, operating parameters of the hydrostatic power unit, mainly a swash plate angle of a variable displacement pump, and/or the ratio of the final gear reduction of the driveline, will be automatically varied, continuously if required, by the transmission controller, to achieve and hold an inputted command, usually a speed command. The pump of the hydrostatic power unit is drivingly connected to the engine of the work machine, and the fluid motor is drivingly connected to the planetary power unit. In a power generation mode, the pump operates to pump pressurized fluid through the motor at a rate determined by the engine speed, a ratio of connecting gears, and the swash plate angle, to rotate the motor, which, in turn, drives an element of the planetary power unit, usually the ring gear. The direction of rotation is also determined by the swash plate angle. In a regeneration mode, the direction of power through the hydrostatic power unit is reversed, and the ring gear of the planetary power unit drives the fluid motor, operating it as a pump, and the pump as a motor.
[0009] It has been observed that the fluid pressure condition in the hydrostatic power unit will be high when the transmission driveline is subjected to high torque loads, which is of concern for the purposes of the present invention, typically when the machine is moving slowly, or is stationary, under heavy load. An operational example would be a tractor pushing or pulling a heavy load, or towing an implement such as a deep subsurface tillage tool. As noted above, if prolonged, damage to the driveline will likely result, so it is desired to avoid this.
[0010] It has also been observed that the hydrostatic power unit will have a mechanical efficiency which is a function of the pressure in that unit, swash plate angle, and pump speed. The efficiency will have a value of less than 1 when in the generation mode, and greater than 1 when in the regeneration mode. The motor of the hydrostatic power unit will have a mechanical efficiency which is a function of the pressure in that unit. Again, this pressure will be important for the purposes of the present invention only when high, approaching relief pressure, when potentially damaging driveline torque conditions are likely to be present. The driveline torque can reach a potentially damaging high level when the hydrostatic power unit is in the generation mode wherein the pump of that unit is functioning as a pump, and also when in the regeneration mode when the pump is being driven by the motor. The efficiency of the motor will preferably be determined by testing at least one high pressure for each operating mode, and recorded for later use. The efficiency value will be greater than 1 for the regeneration mode, and less than 1 for the generation mode.
[0011] According to one aspect of the invention, it has been found that the pressure in the hydrostatic power unit will provide an indication of the torque on that unit, and if the operating mode, e.g., generation, regeneration, and the mechanical efficiency of the fluid motor and direction of operation thereof are known at the pressure, a relatively accurate estimation of the torque on the fluid motor can be made. In turn, the torque on the output of the planetary power unit can be estimated as a function of the torque on the fluid motor and ratios of gears of the planetary unit and those connecting it with the motor. The accuracy of this torque can be increased by knowing the efficiency of the planetary unit. The torque load on the driveline, particularly on the output member thereof, can then be estimated as a function of the estimated torque on the planetary unit output, and the ratio of gears connecting the planetary unit to the driveline output member.
[0012] Thus, according to a preferred aspect of the invention, a method of the invention includes a step of monitoring operation of the hydrostatic power unit of the transmission to determine whether that unit is operating in a generation mode or a regeneration mode. The method will then determine a mechanical efficiency of the hydrostatic power unit, in particular the motor thereof, as a function of at least the operating mode, a pressure therein and an operating speed thereof, e.g., motor speed. This can be, for instance, a selected constant value for a particular high pressure value, or it can be a stored value previously determined from testing as noted above. The torque output of the hydrostatic power unit will then be estimated as a function of at least the pressure therein and the mechanical efficiency of the motor.
[0013] As a next step according to the invention, the torque output of the planetary power unit will be estimated, as a function of the estimated torque output of the hydrostatic power unit, a ratio of gears drivingly connecting the hydrostatic power unit to the planetary power unit, and ratios of the gears of the planetary unit. The torque on the output member of the driveline of the transmission will then be estimated as a function of the estimated torque output of the planetary power unit and ratios of gears drivingly connecting the planetary unit to the output member.
[0014] According to another aspect of the invention, if the estimated torque on the output member is greater than a predetermined value, for instance, a threshold value above which damage to the driveline is likely to occur, then an operating parameter of the transmission will be changed to reduce the torque. As one example, if the machine is moving, the speed of movement can be lowered, but preferably without reducing engine speed, such that other systems run by the engine are not affected. As another example, the swash plate angle can be changed, to lower the pressure in the hydrostatic power unit and thus the torque output thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a side view of a representative work machine including a continuously variable hydro-mechanical transmission controlled according to the method of the invention;
[0016] FIG. 2 is a simplified schematic representation of the work machine of FIG. 1 , showing one of the embodiments of the transmission;
[0017] FIG. 3 is a simplified schematic representation of the work machine, showing another embodiment of the transmission;
[0018] FIG. 4 is a simplified schematic representation of another embodiment of the transmission;
[0019] FIG. 5 a partial sectional view of an exemplary embodiment of a planetary power unit for the transmission of FIG. 2 ;
[0020] FIG. 6 is a high level flow diagram showing steps of the method of the invention; and
[0021] FIG. 7 is a partial view of an exemplary embodiment of a planetary power unit for the transmission of FIG. 3 .
DETAILED DESCRIPTION OF THE INVENTION
[0022] Referring now to the drawings, in FIG. 1 a work machine 1 is shown, which is a tractor representative of those that can be used for a variety of uses, including, but not limited to, agriculture, construction, earth moving and forestry. Work machine 1 includes a power source 4 which will be, for instance, an internal combustion engine, and is mechanically coupled to a continuously variable hydro-mechanical transmission, three representative variants or embodiments of which are represented by numbers 10 A, 10 B and 10 C, like parts of which being identified by like numbers. Each of transmissions 10 A, 10 B and 10 C is controllably operable according to the method of the invention, for estimating and limiting driveline torque of the transmission, and the transmissions shown are intended to be exemplary of a wide range of possible hydro-mechanical architectures wherein the power is split between paths and different ranges are used, with which the present invention can be used.
[0023] Referring also to FIGS. 2 , 3 and 4 , each of transmissions 10 A, 10 B and 10 C includes a hydrostatic power unit 12 and a planetary power unit 30 which are coupled to a driveline including a range gear set 58 mounted within a transmission housing 11 and coupled to a load L which here is the drive wheels of machine 1 as shown in FIG. 1 . It should be understood that machine 1 can alternatively include a load L that comprises a track drive, or an operating system of the machine such as but not limited to, a power take off (PTO).
[0024] Referring in particular to FIG. 2 , hydrostatic power unit 12 of transmission 10 A includes a fluid pump 16 coupled by fluid conduits 17 in a closed loop to a fluid motor 18 . Power unit 12 includes a first input shaft 14 drivingly connected to pump 16 and a first output shaft 20 drivingly connected to motor 18 . Power unit 12 is coupled to a synchronous lockup clutch 24 by first output shaft 20 . Depending upon the desired speed of work machine 1 or the desired rpm of the load L, inputted to a processor based controller 100 by an input device 102 located preferably in operator cab 104 of machine 1 , clutch 24 will be automatically actuated by controller 100 to couple drive gear 26 to input shaft 36 , or drive gear 28 to input shaft 40 , to select an appropriate hydrostatic input gear range. At the same time, controller 100 also adjusts the angle of a swash plate of pump 16 . As an exemplary embodiment, pump 16 can be an electronically controlled variable displacement hydraulic pump. A hydrostatic power unit driving gear 7 coupled to the input shaft 6 from the power source 4 with the hydrostatic power unit driving gear 7 engaging a hydrostatic power unit driven gear 8 that is coupled to the first input shaft 14 drives the hydrostatic power unit 12 .
[0025] Planetary power unit 30 is coupled to the power source 4 with a second input shaft 32 and the input shaft 6 . The planetary power unit 30 also includes a third input shaft 36 , a fourth input shaft 40 and a second output shaft 44 . The second input shaft 32 , the third input shaft 36 , the fourth input shaft 40 and the second output shaft 44 are all coaxial with the second input shaft 32 inside the hollow third input shaft 36 which in turn is within the fourth input shaft 40 as shown in FIG. 5 . The planetary power unit 30 is selectively coupled to the load L; selectively coupled to the hydrostatic power unit 12 ; and coupled to the power source 4 , automatically by controller 100 utilizing various clutches as will be described below. The hydro-mechanical transmission 10 A also includes a load shaft 60 which is coupled to the load L and mounted for rotation in the housing 11 . An intermediate shaft 56 rotatably mounted in the housing 11 supports a range gear set 58 mounted for rotation in the housing 11 and selectively coupled to the planetary power unit 30 and the load shaft 60 .
[0026] The planetary power unit 30 comprises a primary sun gear 34 coupled to the second input shaft 32 , which is directly coupled to the power source via input shaft 6 . A secondary sun gear 38 is coupled to the third input shaft 36 , which is selectively coupled to the first output shaft 20 by synchronous lockup clutch 24 under control of controller 100 . A ring gear 42 is coupled to the fourth input shaft 40 , which is selectively coupled to the first output shaft 20 also with the synchronous lockup clutch 24 under control of the controller. A compound planetary gear cluster 46 mounted on a compound planetary gear carrier 48 engages with the primary sun gear 34 , the secondary sun gear 38 and the ring gear 42 . The compound planetary gear carrier 48 is coupled to the second output shaft 32 of the planetary power unit 30 . Compound planetary gear carrier 48 supports three compound planetary gears 47 which make up the compound planetary gear cluster 46 .
[0027] The synchronous lockup clutch 24 is controlled by controller 100 to selectively engage driving gears 26 and 28 which engage third input shaft 36 and fourth input shaft 40 , respectively. When driving gear 26 is driven by the hydrostatic power unit 12 , it drives the secondary sun gear 38 . When driving gear 28 is driven by the hydrostatic power unit 12 , it drives the fourth input shaft 40 , which in turn drives the ring gear 42 within planetary power unit 30 . The above described power transmissions occur in the upstream side of unit 30 of the hydro-mechanical transmission 10 A. On the down stream side of unit 30 a single output shaft, designated as the second output shaft 44 is coupled within unit 30 with the compound planetary gear carrier 48 . The second output shaft 44 is coupled to the directional clutch 50 , which has a forward component 54 and a reverse component 52 which respectively drive gears 55 and 53 to control the forward or reverse directions of the work machine 1 , as selected by the operator through controller 100 .
[0028] Intermediate shaft 56 is rotatably mounted in the housing 11 and supports a road range input gear 62 , which in turn engages a road range output gear 64 mounted on the load shaft 60 . A work range input gear 66 coupled to the intermediate shaft 56 engages a work range output gear 68 also mounted on the load shaft 60 . A reverse gear 70 is coupled to the intermediate shaft 56 and engages an idler reverse gear 72 mounted on the load shaft 60 . A range selector 74 is coupled to the load shaft and is controlled by the operator of machine 1 to select either the road range speeds or the work range speeds. In an exemplary embodiment of the hydro-mechanical transmission, the range selector 74 is a sliding collar or synchronizer 76 .
[0029] Once the operator selects between the working range and road range speeds, controller 100 will automatically control the pump swash plate angle in the hydrostatic power unit 12 and the selection of one of the drive gears 26 or 28 coupled to the first output shaft 20 to achieve speed control. In low speeds, the hydrostatic drive is driven through ring gear 42 , which is coupled to the fourth input shaft 40 and is driven by driving gear 28 . The gear ratios in the planetary power unit 30 are designed so that a synchronous condition will occur at the most desirable speed within a given working range. With machine 1 starting from rest, the swash plate angle of the hydraulic motor 18 is automatically increased in order to increase machine or rpm speed until a synchronous speed is reached (i.e., the two sun gears, 34 and 38 , the ring gear 42 and the planet carrier 48 , supporting the compound planetary gear cluster 46 all rotate at the same speed). At that same speed, the synchronous lockup clutch 24 will be automatically actuated to disengage driving gear 28 and engage driving gear 26 to drive the secondary sun gear 38 . With such change occurring automatically at a synchronous speed it is “seamless” with little or no energy dissipation. With the hydrostatic drive power being delivered through the secondary sun gear 38 , the swash plate angle is reduced to increase speed of the compound planetary gear carrier 48 until a maximum speed of machine 1 is reached. It is also possible to engage both drive gears 26 and 28 with the synchronous lockup clutch 24 and with disconnect clutch 22 disconnecting output shaft 20 in which all gears of the planetary power unit 30 will be transmitting power and thereby providing a very high efficiency through the hydro-mechanical transmission 10 A. Under some operating conditions, controller 100 will completely disengage the hydrostatic power unit 12 from the planetary power unit 30 through the hydrostatic disconnect clutch 22 . In such instance, only direct mechanical power from the power source 4 is provided to the planetary power unit driving only the primary sun gear 34 which in turn drives the compound planetary gear cluster 46 and the second output shaft 44 .
[0030] It is also possible for a full shuttle reverse in either the work range or road range by means of the directional clutch 50 . Since the directional change occurs downstream of the planetary power unit 30 , it is not necessary to change the swash plate position of the pump 16 in the hydrostatic power unit 12 if the same forward to reverse ratio is retained.
[0031] The configuration of the hydro-mechanical transmission, described above provides that the synchronized ratio change gear speeds takes place on the input side (upstream side) of the planetary power unit 30 in the hydrostatic power unit 12 with only one output shaft 44 from planetary power unit 30 , under control of controller 100 .
[0032] The control of the various clutches and the swash plate angle of the pump 16 in the hydrostatic power unit 12 , will be automatically controlled by controller 100 , using actuators 106 connected to controller via suitable conductive paths 108 , which can be wires of a wiring harness, a wired or wireless communications network or the like, and which also connect to input device 102 . Transmission 10 A also includes appropriate sensors, including pressure sensors 110 for sensing pressure conditions in conduits 17 connecting pump 16 and motor 18 , and speed sensors 112 for sensing a speed of first output shaft 20 and a speed of load shaft 60 , all connected to controller 100 via conductive paths 108 . Controller 100 is connected to power source 4 , also via conductive paths 108 , to receive data such as speed data, e.g., of input shaft 6 , therefrom.
[0033] Referring in particular to FIG. 3 , the second embodiment of a hydro-mechanical transmission 10 B eliminates the operator preselected work range or road range of speeds per se. However, seamless speed changes from zero to a maximum speed, such as 50 km per hour can be obtained through four gear ranges defined as range “A”, “B”, “C”, and “D” with synchronized shift points between each range to obtain the seamless speed changing. In this embodiment, the synchronized ratio changing is automatically controlled by a controller 100 and takes place on the output side (downstream side) of the compound planetary power unit 30 which has two coaxial output shafts 44 and 45 . As with transmission 10 A above, controller 100 is connected to the various actuators 106 of the clutches and pump 16 , pressure sensors 110 , and speed sensors 112 , and also to input device 102 and power source 4 , for receiving commands and data, via conductive paths 108 .
[0034] Power source 4 of hydro-mechanical transmission 10 B selectively drives hydrostatic power unit 12 and planetary power unit 30 , which in turn drives a plurality of range gear sets 58 which are coupled to a load L, which, again, will typically be the wheels or tracks of machine 1 . Hydrostatic power unit 12 as shown in FIG. 3 is contained within the hydro-mechanical transmission housing 11 but it may also be external to the housing 11 and accessed with appropriate couplings. The hydrostatic power unit 12 includes a pump 16 coupled to a motor 18 with the hydrostatic power unit 12 coupled to a first input shaft 14 and a first output shaft 20 . The power to the hydrostatic power unit 12 is provided by a driven gear 8 mounted on the first input shaft 14 and engaged with a hydrostatic power unit driving gear 7 mounted on the input shaft 6 of the power shaft 4 . The pump 16 is in fluid communication with the motor 18 by appropriate conduits 17 . The first output shaft 20 rotatably supports a gear for engaging a third input shaft of unit 30 as described below.
[0035] Planetary power unit 30 of transmission 10 B includes a second input shaft 32 , a third input shaft 36 , a second output shaft 44 and a third output shaft 45 (see FIG. 7 also). Unit 30 is selectively coupled to the load L, coupled to the hydrostatic power unit 12 and selectively coupled to the power source 4 . The unit 30 can be connected to a plurality of range gear sets 58 as will be described below. The second input shaft 32 , the third input shaft 36 , the second output shaft 44 , and the third output shaft 45 are coaxial with the third input shaft being hollow and the second input shaft 32 being supported within the third input shaft 36 . The second output shaft 44 is hollow and third output shaft 45 is supported within the hollow second output shaft 44 . The hydro-mechanical transmission 10 B also includes a load shaft 60 coupled to the load L and mounted for rotation in the housing. An intermediate shaft 56 supporting a plurality of range gear sets 58 is mounted for rotation in the housing and selectively coupled to unit 30 and the load shaft 60 .
[0036] The planetary power unit 30 of the hydro-mechanical transmission 10 B comprises a primary sun gear 34 , which is coupled to the second input shaft 32 . A ring gear 42 is coupled to the third input shaft 36 and coupled to the first output shaft 20 with the hydrostatic power unit with the gear 26 engaging the third input shaft 36 . A compound planetary gear cluster 46 mounted on a compound planetary gear carrier 48 and engaged with the secondary sun gear 38 and the ring gear 42 is mounted within unit 30 . A compound planetary gear carrier 48 is coupled to the second output shaft 44 . The compound planetary gear cluster 46 includes three compound planetary gears 47 .
[0037] In operation, the continuously variable hydro-mechanical transmission 10 B can be operated to have a combined hydrostatic and mechanical power flow by engaging the reverse clutch 52 or forward clutch 54 which respectively drive a reverse drive gear 53 and a forward drive gear 55 which in turn drives the first input shaft 20 and the second input shaft 32 . It is also possible to operate the hydrostatic mechanical transmission 10 B for a pure hydrostatic power flow by disengaging both clutches 52 and 54 in which case the second input shaft 32 is not directly driven by the power source 4 . In the pure hydrostatic mode, one range gear is coupled to carrier 48 and another range gear 58 is connected to the secondary sun gear 38 simultaneously.
[0038] The plurality of arranged gear sets 58 comprise an A-range output gear 80 coupled to the intermediate shaft 56 and engaged with an A-range input gear 82 mounted on the second output shaft 44 . A B-range output gear 84 is coupled to the intermediate shaft 56 and engaged with a B-range input gear 86 mounted on the third output shaft 45 . A C-range output gear 88 coupled to the intermediate shaft 56 and engaged with a C-range input gear 90 is mounted on the second output shaft 44 . A D-range output gear 92 is coupled to the intermediate shaft 56 and engaged with D-range input gear 94 mounted on the third output shaft 45 . A plurality of range selectors 74 are coupled to the intermediate shaft to provide the selection of range gear sets, under control of controller 100 . A typical range selector 74 in this exemplary embodiment is a clutch 77 associated with the respective range gear sets. A main input drive gear 96 is coupled to the intermediate shaft 56 and engaged with a main output drive gear 98 , which is mounted on the load shaft 60 .
[0039] As stated above in this embodiment, there is no selection for a work range or road range per se. However, the four ranges (A-D) provide a seamless transition between ranges similar to the work/road configuration previously described. Speed change from zero to maximum speed is achieved in a smooth and continuous manner by changing the swash plate angle of the pump 16 under control of controller 100 . For high efficiency, the first stall point of the motor 18 in the hydrostatic power unit 12 (i.e., ring gear 42 is a relative zero speed point) is selected in the 7 to 9 km per hour optimum speed range in order to transmit 100% of the power from the power source 4 . A full shuttle reverse is also available through the clutches 52 and 54 since the directional change occurs on the input side (upstream side) of the planetary power unit 30 . Since directional changes occur on the input side of unit 30 , it may be necessary to adjust the position of the swash plate in motor 18 depending upon the desired forward to reverse speed change ratio, and this is done automatically by controller 100 . In the low speed pure hydrostatic power flow regenerative heat is kept under control during prolonged creep operation of the work machine 1 . Also, in the pure hydrostatic power flow mode, different creep speed ranges can be achieved by engaging different combinations of the range clutches. For example, range gear set A, 80 , 82 and B range set 84 , 86 can be simultaneously engaged through their respective range selectors 74 . Similarly, range set 80 can be combined with C or D to obtain a different creep speed range as selected by the operator of the work machine 1 . With this embodiment, it is also possible to shuttle between forward and reverse in either the combined hydro-mechanical mode or the pure hydrostatic mode. Further, in this embodiment, the machine speed can be controlled independent of engine speed enabling constant output speed from the PTO during implement operation.
[0040] Referring in particular to FIG. 4 , the third embodiment of a hydro-mechanical transmission 10 C, like embodiment 10 B just discussed, eliminates the operator preselected work range or road range of speeds per se. Again, seamless speed changes from zero to a maximum speed, such as 50 km per hour can be obtained through four gear ranges defined as range “ 1 ”, “ 2 ”, “ 3 ”, and “ 4 ” with synchronized shift points between each range to obtain the seamless speed changing. The synchronized ratio changing is automatically controlled by the controller and again takes place on the output side (downstream side) of the planetary power unit 30 which is constructed in the above described manner and has two outputs: a secondary sun gear NS 2 , and planetary gear carrier N 13 . As with transmissions 10 A and 10 B above, the controller is connected to the various actuators 106 of the clutches and pump 16 , pressure sensors 110 , and speed sensors 112 , and also to an input device and power source 4 which is an engine, via conductive paths 108 .
[0041] Power source 4 of hydro-mechanical transmission 10 B selectively drives hydrostatic power unit 12 and planetary power unit 30 , which in turn via secondary sun gear NS 2 and planetary gear carrier N 13 , will drive selected ones of a plurality of range gear sets 58 which are coupled to a load L, which, again, will typically be the wheels or tracks of machine 1 . Gear sets 58 are variously engageable by range selectors R 1 , R 2 , R 3 and R 4 under control of the controller. The hydrostatic power unit 12 includes a pump 16 in a fluid loop with a motor 18 with the hydrostatic power unit 12 coupled to power source 4 via an input gear N 6 and having an output gear N 10 . The power to the hydrostatic power unit 12 is provided by a driven gear N 4 mounted on the forward shaft and engaged with gear N 6 . Output gear N 10 is connected to ring gear NR of planetary power unit 30 via gears N 11 and N 12 .
[0042] Planetary power unit 30 is constructed essentially as shown in FIG. 7 but is numbered differently, including a primary sun gear NS 1 on a planetary input shaft connectable with power source 4 via a forward clutch 54 or a reverse clutch 52 . Power unit 30 is selectively coupled to the load L, coupled to the hydrostatic power unit 12 and selectively coupled to the power source 4 , under automatic control of the controller. For connection to the load L, the hydro-mechanical transmission 10 C includes an output shaft 60 coupled to the load L which carries an input gear N 18 engaged with an output gear N 17 on a range 1 / 2 shaft of range gear set 58 , and a gear N 22 engaged with a gear N 19 on a range 3 / 4 shaft. The range 1 / 2 shaft can be coupled to planetary power unit 30 via automatic operation of range selectors R 1 and R 3 for power flow through gears N 13 and N 14 , or N 15 and N 16 , respectively. The range 3 / 4 shaft can be coupled to unit 30 via range selectors R 3 and R 4 for power flow via gears N 13 and N 20 , or N 15 and N 21 . Range 1 / 2 shaft and range 3 / 4 shaft can also be simultaneously coupled to power unit 30 , to provide dual power flow.
[0043] In operation, the continuously variable hydro-mechanical transmission 10 C can be operated to have a combined hydrostatic and mechanical power flow by engaging the reverse clutch 52 to power planetary power unit 30 via gears N 1 , N 3 , N 5 and N 7 , or engaging forward clutch 54 to power it via gears N 1 , N 8 , and N 2 . It is also possible to operate the hydrostatic mechanical transmission 10 C for a pure hydrostatic power flow by disengaging both clutches 52 and 54 .
[0044] As stated above in this embodiment, there is no selection for a work range or road range per se. However, the ranges provide a seamless transition between ranges similar to the work/road configuration previously described. Speed change from zero to maximum speed is achieved in a smooth and continuous manner by changing the swash plate angle of the pump 16 under control of controller 100 . A full shuttle reverse is also available through the clutches 52 and 54 since the directional change occurs on the input side (upstream side) of the planetary power unit 30 . Since directional changes occur on the input side of compound planetary unit gear 30 , it may be necessary to adjust the position of the swash plate in motor 18 depending upon the desired forward to reverse speed change ratio, and this is done automatically by controller 100 . In the low speed pure hydrostatic power flow regenerative heat is kept under control during prolonged creep operation of the work machine 1 . Also, in the pure hydrostatic power flow mode, different creep speed ranges can be achieved by engaging different combinations of the range selectors R 1 -R 4 .
[0045] As noted above, it has been observed that under some operating conditions, torque loads on components of the continuously variable hydro-mechanical transmissions 10 A, 10 B or 10 C can be sufficient, particularly if sustained, to damage the transmission. Such damage has been observed to be more prevalent in the driveline or output portions of the transmissions, that is, in the final gear reduction in connection with load shaft 60 and related elements.
[0046] According to the invention, a method of estimating driveline torque of a of a work machine, particularly in the final gear reduction or output member, and limiting the torque for preventing damage to the transmission, and thus eliminating need for torque sensors, is provided. According to the invention, it has been observed that the fluid pressure condition in the hydrostatic power unit 12 will be high when the transmission driveline is subjected to high torque loads, typically when the machine is moving slowly, e.g., creep conditions, or is stationary, under heavy load. It has also been observed that the hydrostatic power unit 12 will have a mechanical efficiency which is a function of the pressure in that unit, swash plate angle, and speed of pump 16 . The efficiency will have a value of less than 1 when in the generation mode, and greater than 1 when in the regeneration mode. The motor 18 of the hydrostatic power unit 12 will have a mechanical efficiency which is a function of the pressure in that unit. This pressure will be important for the purposes of the present invention only when high, approaching relief pressure, when potentially damaging driveline torque conditions are likely to be present. The efficiency of the motor 18 can be determined by testing at relevant high pressure, e.g., near relief, and recorded for later use. The efficiency value will be greater than 1 for the regeneration mode, and less than 1 for the generation mode.
[0047] It has been further found that the pressure in the hydrostatic power unit 12 will provide an indication of the torque on that unit, and if the operating mode, e.g., generation, regeneration, and the mechanical efficiency of the fluid motor 18 and direction of operation thereof are known or accurately estimated at the pressure, a relatively accurate estimation of the torque on the fluid motor 18 can be made. In turn, the torque on the output of the planetary power unit 30 can be estimated as a function of the torque on the fluid motor 18 and ratios of gears of the planetary unit 30 and those connecting it with the motor 18 . The accuracy of this torque estimation can be increased by knowing or estimating the efficiency of the planetary unit 30 . The torque load on the driveline, particularly on the output member, e.g. load shaft 60 , thereof, can then be estimated as a function of the estimated torque on the planetary unit output, and the ratio of gears connecting the planetary unit 30 to the driveline output member.
[0048] Referring also to FIG. 6 , a high level flow diagram 114 showing steps of a preferred method of the invention for estimating and limiting driveline torque is shown. The steps of diagram 114 will be performed automatically by the transmission controller, e.g., controller 100 , based on command values, e.g., swash plate angle commands and clutch actuation commands outputted to or feedback received from actuators 106 , input commands; sensor data received from pressure sensors 110 and speed sensors 112 ; and also data received from the machine power unit 4 . At block 116 , operation of the hydrostatic power unit of the transmission is monitored or read, to determine whether that unit is operating in a generation mode or a regeneration mode. This will be determined from a differential between pressure outputs of sensors 110 , and also which sensor has a higher or lower pressure, which will be indicative of whether the pump is acting as a pump (generation) or as a motor (regeneration), which will be determined at decision block 118 . The invention will then determine a mechanical efficiency of the hydrostatic power unit, in particular, of the motor thereof, as a function of at least the operating mode, e.g., generation or regeneration; pressure; and motor speed, as denoted by respective blocks 120 and 122 . The efficiency can be determined by looking up a stored value, previously obtained from testing.
[0049] The torque output of the hydrostatic power unit will then be estimated as a function of at least the pressure therein and the mechanical efficiency of the motor, as denoted at block 124 . The torque in the motor T motor in N*m in the hydro-mechanical operating mode can be estimated using the following equation.
[0000]
T
motor
=
P
HSU
·
V
motor
2
·
π
·
η
Motor
[0000] where P HSU is the pressure in the hydrostatic power unit in Pa (N/m 2 ); V motor is volume of the motor in m 3 ; and n motor is the mechanical efficiency of the motor. The pressure is positive for non-regenerative mode and negative for re-generation mode. The motor mechanical efficiency is a function of hydrostatic power unit pressure, but as noted above, is only of concern when output torque is high. When torque is high, the hydrostatic power unit pressure will also be high, such that the mechanical efficiency will need only be determined near the relief pressure. The motor efficiency is also slightly a function of the swash plate angle and pump speed, but it has been found that this can be neglected. The best practice has been found to be to measure the efficiency using torque sensors or gauges, as part of a temporary or removable test apparatus, prior to installation of the motor or hydrostatic power unit, and then to save the test values and look up them up later during the transmission operation.
[0050] As a next step, the torque output of the planetary power unit will be estimated, as a function of the estimated torque output of the hydrostatic power unit, a ratio of gears drivingly connecting the hydrostatic power unit to the planetary power unit, and ratios of the gears of the planetary power unit, as denoted at block 126 .
[0051] The torque at the planetary output can be estimated as follows.
[0000] For Range 1 and 3 of transmission 10 C of FIG. 4 , the planetary output torque is denoted T P13 .
[0000]
T
P
13
=
T
m
·
(
N
12
N
10
)
K
1
·
(
K
1
-
1
)
[0000] where N 12 is the number of teeth of gear N 12 ; N 10 is the number of teeth of gear N 10 ; and K 1 is determined according to the formula below.
[0000]
K
1
=
-
N
R
N
P
2
·
N
P
1
N
S
1
[0000] where N R is the number of teeth of the ring gear of the planetary; N P1 is the number of teeth of each planet gear NP 1 ; N P2 is the number of teeth of each planet gear NP 2 ; and N S1 is the number of teeth of the primary sun gear NS 1 .
For Range 2 and 4 , the planetary output torque is denoted T P24 .
[0000]
T
P
24
=
T
m
·
(
N
12
N
10
)
(
(
K
2
-
1
)
K
1
(
K
2
-
K
1
)
)
·
[
(
K
2
-
1
)
·
K
1
(
K
2
-
K
1
)
-
1
]
and
K
2
=
N
S
2
N
P
2
·
N
P
1
N
S
1
[0000] where N S2 is the number of teeth of the secondary sun gear NS 2 .
[0052] The torque on the output member of the driveline of the transmission will then be estimated as a function of the estimated torque output of the planetary power unit and ratios of gears drivingly connecting the planetary power unit to the output member, as denoted at block 128 .
[0000] The output torque can now be written in terms of the planetary torque for each range as follows.
For Range 1 , the output torque T 01 is estimated using the equation
[0000]
T
O
1
=
T
P
(
N
13
N
14
)
·
(
N
17
N
18
)
·
η
plantery
[0000] where N 13 is the number of teeth of the gear N 13 ; N 14 is the number of teeth of gear N 14 ; N 17 is the number of teeth of gear N 17 ; N 18 is the number of teeth of gear N 18 , and n is the efficiency of the planetary power unit, which can be known or determined through testing.
For Range 2 , the output torque T 02 is estimated using the equation
[0000]
T
O
2
=
T
P
(
N
15
N
16
)
·
(
N
17
N
18
)
·
η
plantery
[0000] where N 15 is the number of teeth of the gear N 15 ; and N 16 is the number of teeth of gear N 16 .
[0053] For Range 3 the output torque T 03 is estimated using the equation
[0000]
T
O
3
=
T
P
(
N
13
N
20
)
·
(
N
20
N
22
)
·
η
plantery
[0000] where N 19 is the number of teeth of the gear N 19 ; N 20 is the number of teeth of gear N 20 ; N 21 is the number of teeth of gear N 21 ; and N 22 is the number of teeth of gear N 22 .
[0054] For Range 4 , the output torque T 04 is estimated using the equation
[0000]
T
O
4
=
T
P
(
N
15
N
21
)
·
(
N
19
N
22
)
·
η
plantery
[0000] where
T O1 =M O1 ·M P13 ·T m
T O2 =M O2 ·M P24 ·T m
T O3 =M O3 ·M P13 ·T m
T O4 =M O4 ·M P24 ·T m
[0055] where
[0000]
M
P
13
=
(
N
12
N
10
)
K
1
·
(
K
1
-
1
)
M
P
24
=
(
N
12
N
10
)
(
(
K
2
-
1
)
·
K
1
(
K
2
-
K
1
)
)
·
[
(
K
2
-
1
)
·
K
1
(
K
2
-
K
1
)
-
1
]
M
O
1
=
1
(
N
13
N
14
)
·
(
N
17
N
18
)
·
η
plantery
M
O
2
=
1
(
N
15
N
16
)
·
(
N
17
N
18
)
·
η
plantery
M
O
3
=
1
(
N
13
N
20
)
·
(
N
19
N
22
)
·
η
plantery
M
O
4
=
1
(
N
15
N
21
)
·
(
N
19
N
22
)
·
η
plantery
[0056] If the estimated torque on the output member is greater than a predetermined value or limit, for instance, a threshold value above which damage to the driveline is likely or expected to occur, as determined at decision block 130 , then an operating parameter of the transmission will be changed to reduce the torque. In this regard, the speed of the machine or output member can be read from sensor 112 , and if the speed is greater than a predetermined value, as determined at decision block 132 , the speed of movement can be adjusted, e.g., lowered, as denoted by block 134 , but preferably without reducing power source speed, such that other systems run by the engine are not affected. This may entail adjusting the swash plate angle, to lower the pressure in the hydrostatic power unit and thus the torque output thereof. If, at block 136 the speed is not greater than the predetermined value, the hydrostatic power unit can also be adjusted, in the just described manner, to lower pressure therein and thus torque.
[0000] The output torque is related to the drawbar force (or traction force),
[0000] F drawbar =T O ·Ratio Final — Drive /Tire_Radius
[0000] And, if torque loads on the range clutches is important, the torque at each clutch can be related to the output torque of the transmission as follows,
[0000]
T
C
1
C
2
=
T
O
·
(
N
17
N
18
)
and
T
C
3
C
4
=
T
O
·
(
N
19
N
22
)
[0057] It will be understood that the foregoing descriptions are for preferred embodiments of this invention and that the invention is not limited to the specific forms shown. Other modifications may be made in the design and arrangement of other elements without departing from the scope of the invention as expressed in the appended claims.
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The method of estimating and controlling driveline torque in a continuously variable hydro-mechanical transmission uses pressure data and other metrics of a hydrostatic power unit of the transmission in lieu of actual driveline torque data. A mechanical efficiency of the transmission is determined as a function of whether the power unit is operating in a power generation or regeneration mode, and the torque output of the power unit is estimated from that and other hydrostatic parameters. This is used to estimate a torque output of a planetary power unit of the transmission, and the torque on an output member of the driveline is then estimated using that value, and appropriate corrective action taken.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention is directed to a connector device for a sensor or actuator, particularly for surface antennas in magnetic resonance systems, of the type composed of two terminal elements releasably connected to one another, a first of those terminal elements includes a first electrical conductor that is connected to the sensor or actuator and a second of these terminal elements includes a second electrical conductor that is connectible to an evaluation unit, whereby the first and second electrical conductors are coil systems that enable signal transmission by inductive coupling given a connection of the two terminal elements.
[0003] 2. Description of the Prior Art
[0004] The acquisition and forwarding of sensor signals in a radio-frequency system, such as, for example, a magnetic resonance apparatus, makes high demands as to immunity to interference and dependability of the signal transmission. Magnetic resonance tomography is a known technique for acquiring images of the inside of the body of a living examination subject. A magnetic resonance tomography apparatus has a basic field magnet for generating a uniform magnetic field for the polarization of the atomic nuclei in the body to be examined, a number of gradient coils for the location coding of the magnetic resonance signals as well as one or more radio-frequency transmission antennas that emit radio-frequency pulses for triggering the magnetic resonance signals into the body to be examined. The magnetic resonance signals that are generated are acquired via a sensor and are supplied to an evaluation unit for the calculation of the magnetic resonance images. Either the radio-frequency transmission antenna utilized for the excitation of the magnetic resonance signals, referred to as the whole body antenna, or one or more radio-frequency reception antennas not rigidly connected to the magnetic resonance tomography apparatus, referred to as surface antennas, are utilized as sensors. Magnetic resonance images having a better signal-to-noise ratio can be registered with a surface antenna. It is brought close to the body region to be examined and is connected via a connecting cable to the evaluation unit of the magnetic resonance tomography apparatus.
[0005] The connection between the surface antenna and the evaluation unit is currently designed as a galvanic plug-type connector wherein one of the two terminal elements, that are releasably connectable to one another, is connected to the surface antenna and the other is connected to the evaluation unit. These plug-type connectors have the advantage of a flexible manipulation, since the surface antennas can be removed in a simple way and replaced by other surface antennas and can be connected to the evaluation unit via the plug-type connector.
[0006] One disadvantage of the known plug-type connectors, however, is that the electrical contacts can be only inadequately disinfected due to their being freely accessible. In the medical sector, however, a regular disinfection of the examination apparatus is important. Further, the problem arises given the known plug-type connectors that undesired sheath waves propagate on the leads, which may lead to a heating of adjacent body tissue that is unpleasant for the patient.
[0007] German PS 3616389 discloses a proximity switch acting in non-contacting fashion in a different technical field that is composed of a signal-processing part, a main part and a signal-acquiring sensor part that is pluggable to the main part. The signal and energy transmission between the sensor part and the main part given this proximity switch ensues via inductive coupling on the basis of integrated core coils that lie directly opposite one another when the two parts enter into a plug-type connection.
[0008] The same principle of signal transmission by inductive coupling is also utilized in a bio-magnetometer disclosed in German Translation 69029375. With this bio-magnetometer, extremely small magnetic fields are measured, these being generated, for example, by the brain of a patient. The bio-magnetometer contains a superconducting, magnetic pick-coil that is connected to a highly sensitive magnetic signal detector, a SQUID. The entire system is accommodated in Dewar vessels for producing the temperatures required for the super-conduction. The publication proposes that the pick-up coil and the magnetic signal detector be arranged in two different Dewar vessels that are detachably connected to one another. For the signal transmission, transmission coils are situated in each Dewar vessel that are fashioned and arranged such that they are coaxially thrust inside one another given a connection between the two Dewar vessels.
[0009] The principle of signal transmission by inductive coupling utilized in these two publications, however, does not seem suitable for operation in a magnetic resonance system, since the transmission coils are exposed to high radio-frequency fields therein that disturb the signal transmission and are also influenced by it.
SUMMARY OF THE INVENTION
[0010] An object of the present invention is to provide a connector device for a sensor or actuator, particularly for a surface antenna in a magnetic resonance system, that avoids the above disadvantages and can be unproblemmatically disinfected.
[0011] The object is achieved in a connector device according to the invention that is composed of two terminal elements releasably connectible to one another, with a first of these terminal elements includes a first electrical conductor that is connected to the sensor or actuator and a second of these terminal elements includes a second electrical conductor that is connectible to an evaluation unit. The first and second electrical conductor are coil systems that enable signal transmission by inductive coupling where the two terminal elements are connected to one another. Each of the coil systems is formed of at least two series-connected coils that have oppositely directed windings and are dimensioned such that the sum of voltages induced in the coils by a uniform electromagnetic field yields zero for each of the coil systems.
[0012] As a result of this fashioning of the connector device, the signals received by the sensor or sent to the actuator are not galvanically transmitted but are transmitted by inductive coupling between the two terminal elements of the connector device, for example of a plug-type connector. This design enables the complete hermetic sealing of the sensor or actuator with the first terminal element, so that no electrical conductors are exposed. This is especially advantageous for surface antennas that are potentially exposed to body fluids such as, for example, a prostate coil. With the inventive connector device, surface antennas that can be completely disinfected and sterilized can be achieved. In the same way, the second terminal element of the connector device, which may come into contact with the patient, can be completely hermetically sealed. As a result of a complete encapsulation, all disinfection measures can be unproblemmatically implemented, so that the inventive connector device is excellently suited for utilization in the medical field.
[0013] In the inventive connector device, reduction emission from the coupled connection, and the influence of external radio-frequency fields, are achieved by a special design of the two coil systems in the terminal elements. Each of the coil systems is formed of at least two series-connected coils that have oppositely directed windings and are dimensioned such that the sum of currents induced in the coils due to a uniform electromagnetic field yields zero for each of the coil systems. This is achieved by a suitable selection of the area and the number of turns in conjunction with the direction of the winding of the individual coils. The sum of the product of area and number of turns for all individual coils of each coil system must yield approximately zero, whereby oppositely directed numbers of turns are distinguished by opposite operational signs. Only as a result of this design is the disturbance-free utilization of the connector element enabled in radio-frequency fields as particularly occur in magnetic resonance systems.
[0014] Each coil system is preferably composed of two series-connected coils with the same dimensioning, i.e. same area and same number of turns, that are wound oppositely (in opposite senses). As a result of this design, the fields generated by the oppositely directed coils of the respective coil systems cancel nearly completely at the exterior of the connector. The fields of the coils are of adequate strength only in the close proximity region wherein the inductive coupling between the coil systems ensues.
[0015] Another advantage of the inventive connector device is that, given the connection via the connector device of one or more surface coils to the evaluation unit, significantly reduced leakage currents occur via the connecting line. By suppressing the common mode, moreover, the sheath waves are also suppressed, so that no heating that is unpleasant for the patient occurs given contact with the connecting cable.
[0016] In contrast to a conventional galvanic plug-type connectors, no wear of electrical contacts occurs given the inventive connector device.
[0017] The invention is explained below with reference to employment wherein the connector device produces a connection between a surface antenna fashioned as coil and the evaluation unit of a magnetic resonance system. Of course, other types of sensors or actuators can be connected to an evaluation unit with the present connector device. Examples are sensors for measuring blood pressure, temperature or a ECG or actuators for generating sound or electrical stimulation The structure of the connector device is the same as given employment with the surface antenna.
[0018] The connector device is composed of two terminals elements releasably connected to one another that are preferably designed as plug-type connectors. Each of the terminal elements contains a coil system. The coil system of one of the terminal elements is electrically connected to the surface coil either directly or via intermediate elements, for example a modulation circuit. The coil system of the other terminal element is connected or at least connectible to the evaluation unit via a connecting cable. For example, a conventional galvanic plug-type connector for the connection to the evaluation unit can be provided at that end of the connecting cable not connected to the coil system. The connecting cable, however, alternatively can be directly connected to the evaluation unit, i.e. non-releasably.
[0019] The terminal elements themselves are composed of an electrically non-conductive material, preferably a plastic. The same materials as are utilized for conventional galvanic plug-type connectors in the present field can be employed as materials in the inventive connector.
[0020] The two terminal elements must be fashioned such that they enable a releasable connection. This can ensue by means of different mechanical mechanisms that are known to a those skilled in the art in the field of releasable mechanical connections.
[0021] The two terminal elements are preferably fashioned as plug-type connectors; for example, one terminal element can represent a socket and the other can represent the appertaining plug.
[0022] In a preferred embodiment of the inventive connector device, the coil systems are fashioned and arranged in the terminal elements such that they are coaxially thrust inside one another when the releasable connection between the terminal elements is produced. This means that the coils of the one terminal element surround the coils of the other terminal element in the connection. In this way, an optimum inductive coupling is achieved between the two coil systems. The terminal elements, of course, must be fashioned such by appropriate shaping so that they enable this mutual positioning of the coil systems as a result of the connection.
[0023] For employment of the inventive connector device in a radio-frequency environment, an especially low emission toward the exterior and a low sensitivity relative to external RF fields must be insured. This is additionally supported in an embodiment of the inventive connector device wherein the coil system that is located at the outside in the coupled state is additionally surrounded by a shielding winding. This shielding winding is fashioned around the outer circumference of that coil system in its terminal element. Since the coupling to the other (inner) coil system of the other terminal element ensues within this shielding winding, the signal transmission is not degraded and the two coil systems are shielded from the environment.
[0024] In an embodiment of the inventive connector device, a loss-free matching network is additionally provided for the compensation of insertion losses in the inductive coupling, this being connected to the two inductances in the terminal elements.
[0025] In addition to the signal transmission from the surface coil to the evaluation unit, the surface coil or electrical components connected thereto can be charged with control signals or be supplied with energy via the connector device. To this end, one or more modulation circuits together with one or more frequency generators are arranged at the side of the second terminal element, for modulating additional control signals and/or signals for generating a supply voltage onto one or more carrier frequencies and for transmitting the modulated signal to the surface coil arrangement. At the other side of the surface coil arrangement, i.e., the first terminal element, at least one demodulation circuit is provided that extracts the corresponding control signals or for the voltage supply signals from the carrier frequency signal and makes the demodulated signal available to the electrical components.
DESCRIPTION OF THE DRAWINGS
[0026] [0026]FIG. 1 schematically illustrates an exemplary embodiment of the terminal elements of the connector device of the present invention.
[0027] [0027]FIG. 2 shows an example of the basic fashioning of the coil systems of the inventive connector device.
[0028] [0028]FIG. 3 shows another example of the basic design of the coil systems of the inventive connector device.
[0029] [0029]FIG. 4 shows an example of a matching circuit for compensating the reactive insertion attenuation in the inventive connector device.
[0030] [0030]FIG. 5 is an example of the electrical arrangement of a surface coil of a magnetic resonance system with the inventive connector device.
[0031] [0031]FIG. 6 is another example of the electrical arrangement of a surface coil of a magnetic resonance system with the inventive connector device.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] [0032]FIG. 1 schematically shows an example of a design of the terminal elements 1 , 2 of the inventive connector device. The first terminal element 1 is fashioned as a cylindrical plug element that can be introduced into a corresponding socket-shaped opening of the second terminal element 2 , fashioned as cooperating member. In this introduced position, which is shown in FIG. 1, the two terminal elements 1 , 2 can be mechanically fixed, for example by means of a snap-in mechanism. The inductances 3 , 4 in the respective terminal elements 1 , 2 are only schematically indicated in FIG. 1. The first terminal element 1 is connected to the housing of the surface coil by a cable or is directly integrated into this housing. The second terminal element 2 is connected to a cable 7 that leads to a component of the magnetic resonance system, particularly to an evaluation unit, or that can be plugged thereto.
[0033] [0033]FIG. 2 shows an example of the design of the coil systems in the terminal elements 1 , 2 as presented, for example, in FIG. 1. FIG. 2 schematically shows the coil arrangement or coil system 3 of the first terminal element 1 and the coil arrangement or coil system 4 of the second terminal element 2 in a condition wherein the two terminal elements 1 , 2 are connected to one another. In this condition, the coil arrangement 3 of the first terminal element 1 is coaxially inserted into the coil arrangement 4 of the second terminal element 2 . The electrical connections of the coil arrangements 3 , 4 to the surface coil 5 or to the system, i.e. to the evaluation unit 6 , are likewise schematically indicated.
[0034] The present example shows an embodiment of the coil systems of the connector device wherein disturbances due to external signals, for example due to the RF excitation field of the whole-body antenna, as well as unwanted emission and feedback of the transmitted signal are reduced. This is achieved by the coupling inductances 3 , 4 of each terminal element 1 , 2 being formed, by two coils 3 a, 3 b, and 4 a, 4 b (rather than being formed of one coil), of the same size having oppositely directed windings. The winding sense is indicated by the arrows in FIG. 2. The coil arrangement of the first terminal element 1 is composed of a lower coil 3 a and an upper coil 3 b with respective winding directions proceeding oppositely. The coils 3 a, 3 b are connected to one another in series. The two coils 4 a and 4 b of the second terminal element 2 are fashioned in the same way. The different winding directions of the coils causes a significant reduction of the field generated by the coils with increasing distance from the coils. In the same way, the coils are insensitive to external electromagnetic fields. The spacing of the two coils 3 a, 3 b, and 4 a, 4 b, of each coil pair should lie in the range of the Helmholtz distance. Given this spacing, a significant reduction of the generated field is achieved in the environment without disadvantageously influencing the inductive coupling between the coil pair 3 of the first terminal element 1 and the coil pair 4 of the second terminal element 2 , which are disposed close to one another given a connection of the two terminal elements 1 , 2 .
[0035] The different dimensioning of the coil arrangements 3 , 4 of the two terminals elements also can be seen from FIG. 2. The coil pair 3 a, 3 b of the plug 1 has a diameter that is smaller than the diameter of the coil pair 4 a, 4 b of the socket 2 . As a result, they can be unproblemmatically inserted into one another. In the connected position, an optimum coupling between the coil pairs 3 and 4 is achieved as a result of the slight spacing of the coils.
[0036] Another example for an arrangement of the coil systems of the terminal elements 1 and 2 of the inventive connector device is shown in FIG. 3. In this Figure, only one coil is shown for each coil system for reasons of simplified illustration, said one coil representing the respective coil system. The two coil systems 3 , 4 of the two terminal elements 1 , 2 , in this embodiment again have different diameters, so that they are inserted into one another when producing the connection. In order to avoid an unwanted emission into the outside space, the coil system of the second terminal element 2 is surrounded with a RF shield 8 in the present example. This shield shields both coil systems 3 , 4 from the outside space when the coil system 3 of the first terminal element 1 is inserted without influencing the coupling between the coil systems 3 , 4 . The shielding, which preferably exhibits the shape of a cup open at one side, is fashioned in the terminal element 2 of the larger coil system 4 .
[0037] Even though the individual coils 3 , 4 , 3 a, 3 b, 4 a, 4 b are shown with two coil windings in the present example, it is evident that the coils also can be fashioned with only one turn or with more than two turns.
[0038] For reducing the insertion losses that occur in an inductive coupling path as in the inventive connector device, a matching circuit can be provided at the two terminal elements 1 , 2 . Such a matching circuit is shown as an example in FIG. 4, which shows an equivalent circuit diagram for the inductive coupling with the two coil systems or, respectively, inductances L 1 ( 3 ) and L 2 ( 4 ). The coupling losses indicated with the equivalent inductance M( 9 ) are compensated by correspondingly selected capacitances having the magnitudes −jω(L 1 −M), −jω(L 2 −M) and −jω2M. Such matching circuits are known to those skilled in the art.
[0039] [0039]FIG. 5 shows an example of the electrical structure of a simple magnetic resonance surface antenna with passive detuning circuit and the present connector device. The surface coils in a magnetic resonance system must be connected to a detuning circuit in order, given an excitation of the examination subject with the radio-frequency pulses, to bring the whole-body antenna out of resonance in order to avoid disturbances. Passive as well as active detuning circuits can be utilized. In the present example, the surface coil 5 is connected to a passive detuning circuit 10 that is composed of a coil and a capacitor as well as a diode circuit. The diodes respond above a specific voltage induced at the coil and thereby produce a detuning of the surface antenna 5 . The antenna 5 is connected via matching network 11 to the inductance 3 of the first terminal element. This is inductively coupled to the inductance 4 of the second terminal element, which is in turn electrically connected to the system 6 . The inductive coupling indicated with the two inductances 3 and 4 in FIG. 5 can ensue with a connector device according to the exemplary embodiments of FIGS. 1 through 3.
[0040] Such an embodiment can be very advantageously utilized in a magnetic resonance system. Since the received magnetic resonance signals are already modulated onto a carrier frequency, no further modulation circuit is required between the surface coil 5 and the inductance 3 of the connector device.
[0041] [0041]FIG. 6 shows a further exemplary embodiment of a magnetic resonance surface antenna 5 with the present connector device. In this exemplary embodiment, the antenna 5 is provided with an active detuning circuit. The active detuning circuit is controlled by a detuning signal transmitted from the magnetic resonance system that is received by a detector 21 . The detuning circuit 10 also includes a capacitor and a coil. The surface coil 5 in this example is connected to an amplifier 17 that additionally amplifies the received magnetic resonance signal. In this example, as well, the signal is transmitted to the system via the connector device having two inductances 3 , 4 .
[0042] In this example, a number of frequency modulators with appertaining frequency generators are provided at the side of the second terminal element with the inductance 4 . One modulator 12 thereby serves the purpose of modulating the detuning signal for the detuning circuit 10 of the surface coil 5 onto a carrier frequency. A further modulator 13 serves the purpose of modulating signals for generating a supply voltage via a further carrier frequency. A demodulator 22 also is provided for extracting the magnetic resonance signal from a carrier frequency. The carrier frequencies with the signals modulated thereon are transmitted via corresponding transmission devices (mixers 14 and 15 ) via the inductances 3 , 4 of the connector device. Accordingly, demodulation units 18 must be provided at the side of the surface coil 5 for extracting the supply voltage from the transmitted carrier frequency and demodulation units 20 must be provided thereat for extracting the detuning signal. Further, a rectifier 19 can be seen in FIG. 5 for converting the received alternating voltage into a DC voltage. A modulator 16 can likewise be arranged at the side of the surface coil 5 for the transmission of the magnetic resonance signal.
[0043] Given this design, it is not only the received magnetic resonance signals that can be transmitted to the system; but also control signals and a voltage supply can be transmitted from the system to the surface coil by means of modulation onto a radio-frequency frequency. The carrier frequencies for the control signals and voltage supplies are selected such that their harmonics lie outside the occurring magnetic resonance spectra as well as outside the intermediate frequency products contained in the signal path. Such intermediate frequencies occur, for example, at 2.5 MHz. The transmission itself can either ensue via a common coupling path in frequency-division multiplex when the signals occupy different frequency bands or can also ensue via separate coupling paths by forming separate connector devices for connector devices having a number of coupling inductances that are independent of one another.
[0044] Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventors to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of their contribution to the art.
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A connector device for a sensor or actuator is composed of two terminal elements releasably connected to one another, A first of these terminal elements including a first electrical conductor that is connected to the sensor or actuator and a second of these terminal elements including a second electrical conductor that is connectible to an evaluation unit. The two electrical conductors are fashioned as coil systems in the terminal elements that enable signal transmission by inductive coupling given a connection of the two terminal elements. Each of the coil systems is formed of at least two series-connected coils that have oppositely directed windings and that are dimensioned such that the sum of voltages induced in the coils by a uniform electromagnetic field yields zero for each of the coil systems. The present connector device can be advantageously utilized for the connection of surface coils to the system of a magnetic resonance system and enables a complete hermetic sealing of the surface coils.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a filtering apparatus and a method for a dual-band sensing circuit, more particularly, a gain of a tunable gain amplifier is externally controlled to determine a switch timing for the notch filters for reducing the interference.
[0003] 2. Description of Related Art
[0004] In general, a high frequency communication module will be designed in accordance with the requirement of the operating frequency spectrum. An RF filter is usually used for filtering the required frequencies. If the required filtered frequency spectrum or energy is higher, the operation order of the filters is higher. Moreover, different requirements of the order are applied to different design variants. The loss of signal strength inside the communication module increases with increasing order of the filters. The larger area of the circuit layout will lengthen the signaling path for the RF element, causing a larger loss in signal strength even though the required energy is supplied.
[0005] Moreover, when the conventional high-frequency communication module is designed to be co-existed with variable-frequency subsystems, such as the wireless local area network WiMAX, GSM or 3G communication module cooperates with the subsystems in the frequencies 1.8 GHz and 5 GHz, whereby a filter with extra transmission zero is usually employed to prevent interference. However, the added transmission zero will increase the circuitry in the communication module, and thus increase the in-band loss.
[0006] While the simultaneous operation of the variant-frequency subsystems will cause interference, this interference won't have too much effect on the whole system. The variable-frequency subsystems don't operate at the same time as above mentioned, but operate alternately. Thus, the general RF filter does not require too much flexibility to handle filtering of the subsystem signals.
[0007] In particular, an adaptive notch filter is used for this wireless communication technology. Since the adaptive notch filter is disposed on an RF signaling path, the bandwidth of the filter is simply controlled to filter a specific frequency band and to respond to a required signal, so as to implement an object rather than a common filter.
[0008] A common filter operates by either low-pass filtering or high-pass filtering, that is, the filter filters out the higher frequency segment or the lower frequency segment respectively. Nevertheless, the mentioned adaptive notch filter is a special type of filter that can separate the signals into two parts, wherein the lower frequency segment of one part and the higher frequency segment of the other part are filtered out and mixed afterwards.
[0009] The technology of the adaptive notch filter used to eliminate the narrowband interference in wideband communication is illustrated in U.S. Pat. No. 6,704,378. The adaptive notch filter selectively filters a received wideband communication signal to eliminate narrowband interference. For determining the presence of narrowband interference, the adaptive notch filter scans various known narrowband channels that lie within the wideband frequency spectrum, thereby finding the interference source by determining the signal strength.
[0010] FIG. 1 shows a wireless communication device including an antenna 10 and a low-noise amplifier 12 connected with the antenna 10 . Further, the received signals are transmitted to a splitter 14 that is used to split the signals into different signaling paths. Some split signals are transmitted to the adaptive notch filter module 16 , and some are transmitted to one narrowband receiver 18 . The signals outputted from the adaptive notch filter module 16 are further transmitted to a wideband receiver 19 .
[0011] The above-mentioned narrowband and wideband indicate two different channels with different frequency spectrums. The signals outputted from every channel are simultaneously transmitted to another system. In this example, the adaptive notch filter 16 can scan every channel to filter the narrowband interference, and couples to another controlling device or other systems such as a network system and telephony system. Moreover, the narrowband receiver 18 can couple with a switch.
SUMMARY OF THE INVENTION
[0012] According to the illustration of the conventional art having the applications on different wireless communication bands or the applications among those bands, the filters therein will produce the mentioned drawbacks. Thus, the present invention provides a filtering apparatus and method for dual-band sensing circuit that can enhance the flexibility of the filters and improve performance for each band. Therefore, the switch timing of the high-band notch filters and low-band notch filters can be controlled precisely, so that one of the tunable voltage amplifiers can be tuned to a suitable gain which is used to switch the RF switch of the communication module.
[0013] Besides, the adaptive notch filter of the present invention is applied to eliminate the communication signaling interference effectively, the filters can also be used to activate the high-frequency notch or low-frequency notch for switching the RF switch by determining the interference strength. Therefore the provided filters can reduce the in-band loss.
[0014] The preferred embodiment of the filtering apparatus for a dual-band sensing circuit of the present invention at least includes a connect port that connects to a communication module with coexisted variable-frequency subsystems. The apparatus further includes a dual-band sensing unit that splits the received signals into high-band, main-band and low-band signals to several sensing paths. The apparatus further includes a frequency detecting unit for detecting the power of the received signals and converting the power to a voltage. The apparatus further includes a tunable gain amplifier for producing a suitable gain by considering the interference and tuning the mentioned voltage. The apparatus includes a comparing unit for processing a comparison operation between the gain-amplified voltage and a reference voltage. So that, the apparatus can precisely control the timing to turn on the notch filters, and effectively filter and suppress the interference.
[0015] The preferred embodiment of the filtering method for a dual-band sensing circuit of the present invention includes a first step of receiving signals, especially the signals generated from a variable-frequency subsystem. Then the received signals are split into respective high-band and low-band signals by filtering. Next, the energy of high-band and low-band signals are calculated respectively, and converted to voltage signals. Next, the controlling signals are generated by manual external control, and the tunable gain amplifier is tuned to obtain a suitable gain for gain-amplifying. After that, the method goes to perform a comparison operation by a comparing unit for controlling the timing to turn on or off the switches. The activation timing for the high-band or low-band notch filter is controlled to filter the signals, and the in-band can be prevented consequently. The outputted signals are sent out through antenna at last.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The foregoing aspects and many of the attendant advantages of this invention will be more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
[0017] FIG. 1 shows a schematic diagram of a conventional wireless communication device;
[0018] FIG. 2 shows a schematic diagram of the embodiment of the filtering apparatus in a dual-band sensing circuit of the present invention;
[0019] FIG. 3 shows a schematic diagram of the embodiment of the claimed filtering apparatus;
[0020] FIG. 4 shows a schematic diagram of the embodiment of the dual-band sensing unit of the present invention;
[0021] FIG. 5 shows the curves of frequency response of the filtering apparatus of the present invention;
[0022] FIG. 6 is a flow chart of the filtering method of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] The present invention is illustrated with a preferred embodiment and attached drawings. However, the invention is not intended to be limited thereby.
[0024] A notch filter is a filter that filters out the signals in a specific frequency spectrum. An object of the filtering apparatus and method for dual-band sensing circuit of the present invention is to provide an adaptive notch filter that is disposed on an RF signaling path. The high-band or low-band notch filter is activated by determining the current interference strength by the filtering apparatus. After that, the bandwidth of the filter can be simply controlled to filter out a specific band so as to decrease an in-band loss and respond a required signal.
[0025] Reference is made to FIG. 2 , which shows an embodiment of the filtering apparatus for dual-band sensing circuit of the present invention. The filtering apparatus connects to an external signal source through a connect port 201 . In the preferred embodiment, the external signal source is implemented as a communication module coexisted with a variable-frequency subsystem. Further, when the signals are transmitted into the filtering apparatus through the connect port 201 . Meanwhile, the signals are through a dual-band sensing unit 21 and being split into high and low frequency segments such as high-band, main-band and low-band sensing paths. Since impedance is incorporated, the bandwidth of frequency spectrum can be filtered effectively and controlled easily for eliminating interference.
[0026] After split frequency, the high-band signals will pass through a high-band detecting unit 22 capable of high-band detection. The high-band detecting unit 22 couples with the dual-band sensing unit 21 , and detects the signaling energy. After that, the detected energy is converted to a voltage and then being transmitted to a tunable gain amplifier 24 coupling to a detecting unit. In the present invention, the tunable gain amplifiers 24 and 25 are disposed in the high-band filtering circuit and low-band filtering circuit respectively. Thus, the way to tune the gain won't amplify the signals of whole system, so that, the main-band signals won't be affected.
[0027] The tunable gain amplifier 24 can receive the control signals outside the filtering apparatus. That is, users can enter the control signals via a terminal 203 to adjust the tunable gain amplifier 24 responsive to the interference caused in the apparatus. Next, a suitable amplified voltage is provided in response to a reference voltage. Since every switch has its own characteristics with an activation voltage, the switches in the filtering apparatus can be turned on and turned off by users' configuration. Further, the notch filters 281 , 282 can be turned on or turned off correspondingly, and then the required signals are sent out via the connect port 202 . Therefore the adaptive notch filters provided by the present invention achieves a customized filtering requirement.
[0028] After that, the gain-amplified voltage will be transmitted to a first comparing unit 26 . The first comparing unit 26 couples to the tunable gain amplifier 24 and introduces a reference voltage. This comparing unit 26 performs a comparison operation between the voltage and the reference voltage, thereby to determine the switches being turned on or off in the RF switching unit 28 . The reference voltage is inputted via a terminal 204 which is configured by the designs of the switches (not shown) in the RF switching unit 28 that couples with the first comparing unit 28 . The reference voltage will influence the result from the comparison operation between the reference voltage and the gain-amplified voltage. For example, a signal 1 (on) or 0 (off) is generated by the comparison operation, thereby to control the operation of the switches for precisely controlling the switch timing of activating the high-band or low-band notch filters.
[0029] The mentioned RF switching unit 28 at least includes the notch filters 281 , 282 applied to high-band or low-band signaling. Each notch filter 281 or 282 can filter out a specific frequency spectrum. Particularly, the switch timing of the notch filters can be controlled by operating with the switches. Thus, the determination of the strength of interference in the apparatus can be used to activate the notch filters for decreasing the in-band loss of whole system.
[0030] The low-band filtering circuit is similar to the mentioned high-band filtering circuit. After split frequency by the dual-band sensing unit 21 , the low-band signals will be transmitted to a low-band detecting unit 23 capable of detecting low-band signals. The energy of the signals are detected firstly, and being converted to voltage signals. Next, the voltage signals are transmitted to another tunable gain amplifier 25 . The tunable gain amplifier 25 can receive a control signal outside the filtering apparatus. The users can also enter the control signal for low frequency filtering via the terminal 205 . By means of gain amplifying, the control voltage can be tuned and entered responsive to the interference caused on the apparatus. Since each switch has its own characteristics of activation voltage, a suitable amplified voltage can be provided to compare with the reference voltage.
[0031] Moreover, a second comparing unit 27 incorporates a reference voltage via a terminal 206 . The reference voltage is configured in response to the characteristics of the switches (not shown) in the RF switching unit 28 . The users use the control signal to configure the gain for amplifying. Next, the comparison operation between the reference voltage and gain-amplified voltage is referred to control the switch timing for each switch in the filtering apparatus. Therefore, a customized filtering requirement is achieved by using the adaptive notch filters, and thereby to control the loss of the apparatus.
[0032] Reference is made to FIG. 3 showing a schematic diagram of the embodiment of the filtering apparatus. In the preferred embodiment, a module coexisted with the variable-frequency subsystems generates signals involving the frequency spectrum 1.8 GHz, 2.4 GHz or 5 GHz in a communication device. The signals can be filtered to generate the signals in variable bands. Meanwhile, the interference among the subsystems with different band should be eliminated. The signals are inputted from an external module via a connect port 201 , and being split into variable frequencies through the dual-band sensing unit 21 —including high-band, main-band and low-band signals. The useless signals will be filter out by the dual-band sensing unit 21 .
[0033] In the diagram, the dual-band sensing unit 21 has a plurality of connect terminals 1 , 2 , 3 , 4 , 5 , and 6 which correspond to the connect terminals of the sensing circuit shown in FIG. 4 . Particularly, a stepped impedance open stub is used to generate a characteristic with transmission zero which is clarified in the description of FIG. 4 .
[0034] The signals split by the dual-band sensing unit 21 are transmitted out via the connect terminals 4 , 5 and 6 . The high-band detecting unit 22 receives the high-band signals via the connect terminal 4 , and converts the detected signals into voltage signals. Next, the users can enter control signal via the terminal 203 to the tunable gain amplifier 24 . In this exemplary embodiment, a voltage controlled amplifier (VCA) embodies this tunable gain amplifier 24 and the amplifier is a frequency-controlled circuit which controls the voltage for adjusting the gain. Particularly, the users can control the voltage externally for controlling the gain of the amplifier, thereby to adjust the signal with tiny voltage. Next, by means of the first comparing unit 26 , a comparison operation is operated with a reference voltage that is inputted via the terminal 204 and being adjusted based on the switches. After the comparison operation by the first comparing unit 26 , a control signal 1 as high voltage or 0 as low voltage is generated.
[0035] Likewise, a low-band detecting unit 23 converts the low-band signals into the voltage signals via connect terminal 6 . The users can send the control signal to the tunable gain amplifier 25 via the terminal 205 for tuning the gain. The amplifier in a preferred embodiment is implemented as a voltage controlled amplifier (VCA). After gain amplifying, the inputted low-band signals is compared with the reference voltage by the second comparing unit 27 , so as to generate the control signal with level high or level low voltage for controlling the switches.
[0036] After the control signal is generated through high-band signaling circuit and the low-band signaling circuit, the signals will be filtered by the notch filters capable of high-band or low-band filtering. According to the embodiment shown in the diagram, the RF switching unit connected with an antenna is a switching circuit which is implemented as a plurality of switches. The switches have different operating characteristics. For example, a first switch 301 and a second switch 302 coupled with the first comparing unit 26 , and a fifth switch 305 and a sixth switch 306 coupled with the second comparing unit 27 are the positive logic RF switches. This kind of positive logic RF switch is turned on as in level high or signal 1 , and turned off as in level low or signal 0 . Otherwise, a third switch 303 coupled to the first comparing unit 26 and a fourth switch 304 couple to the second comparing unit 27 are the negative logic RF switches. This negative logic RF switch is turned on as in level low or signal 0 , and turned off as in level high or signal 1 .
[0037] Referring to the circuit shown in the figure, the first comparing unit 26 couples to the first switch 301 , second switch 302 and third switch 303 , and the second comparing unit 27 couples to the fourth switch 304 , fifth switch 305 and the sixth switch 306 . One object of the present invention is to control the switch timing of the notch filters by means of controlling the switch timing of those switches, and to achieve the adaptive notch filter.
[0038] In the beginning of the operation of the filtering apparatus, the users are required to determine a gain in view of requirements of filtering and interference elimination. A control signal responsive to the gain requirement is inputted via the terminals 203 and 205 . The switch timing for each switch is controlled according to the comparison operation. After that, the high-band and low-band notch filters are used to filter the frequency spectrum accordingly.
[0039] In the current embodiment, when a high-band signal passes through the high-band detecting unit 22 , the tunable gain amplifier 24 and the first comparing unit 26 , a level high signal or signal 1 is generated to turn on the positive logic RF switches including the first switch 301 and the second switch 302 , but to turn off the negative logic RF switch such as the third switch 303 . In the meantime, the related circuit in charge of dealing with the low-band signals generates a level low signal or signal 0 , that is, the second comparing unit 27 generates the level low signal to turn off the positive logic RF switches including the fifth switch 305 and the sixth switch 306 , and turn on the negative logic RF switch such as the fourth switch 304 .
[0040] Correspondingly, if the inputted control signal is a low-band signal which is a variable frequency of the high-band signal, the upper high-band filtering circuit generates the level low signal or signal 0 that will turn off the positive logic RF switch and turn on the negative logic RF switch. Otherwise, the under low-band filtering circuit generates a level-high signal or signal 1 to turn on the positive logic RF switch and turn off the negative logic RF switch.
[0041] According to the above operation, when the input signal is a high-band signal, the generated voltage signal will be used to control the switches. So that, since the signal is transmitted to the high-band notch filter 31 through the first switch 301 , the useless frequency spectrum will be filtered out, and the higher frequency spectrum will be kept. Since the second switch 302 is turned on, the high-band signal can be transmitted to the connect port 202 , and sent out via an antenna. In particular, since the third switch 303 and the fifth switch 305 are turned off, the signal won't be influenced by other inner circuit.
[0042] On the other hand, when the input signal is a low-band signal, the generated voltage signal will turn on the positive logic RF switches including the fifth switch 305 and the sixth switch 306 . After that, the useless frequency spectrum will be filtered out as the signal passes through the low-band notch filter 32 . In the meantime, the negative logic RF switch such as the third switch 303 connecting to the antenna is turned on and the fourth switch 304 is turned off, so the signal can be sent out via the antenna without any inner interference.
[0043] Reference is made to FIG. 4 showing the embodiment of the dual-band sensing unit. There are three paths indicating three mutual coupled circuits with different frequency spectrums other than the conventional two coupled circuits with respective high-band and low-band spectrums. A plurality of connect terminals 1 , 2 , 3 , 4 , 5 and 6 shown in the drawing corresponds to the connect terminals 1 , 2 , 3 , 4 , 5 and 6 of the dual-band sensing unit 21 shown in FIG. 3 . The mentioned three sensing paths has the connect terminals 1 and 4 forming the high-band sensing path, and an open stub 41 (the stepped impedance open stub is for another embodiment) is disposed on the path for filtering some specific spectrums. This high-band sensing path is used to filter out the lower frequency spectrum including the low-band and the main-band parts. The component A indicates a transmission line effect caused on the path.
[0044] Furthermore, the circuit between the connect terminals 2 and 5 forms a main-band sensing path. The interference caused by the coupling effect between the circuits should be considered besides considering the transmission line effect indicated as the components B and D.
[0045] Still further, the circuit between the connect terminals 3 and 6 forms a low-band sensing path. Besides the transmission line effect shown as components C and E, a stepped impedance open stub is disposed on this path for easily controlling two or more frequencies of two or more transmission zeros, and effectively filtering out the useless frequencies such as main-band and high-band spectrums. Consequently, a tunable transmission zero will be generated; therefore, the filtering apparatus can effectively prevent some unnecessary coupled frequencies by well-controlled position of the transmission zero as designing the apparatus.
[0046] Reference is made to FIG. 5 showing the curves of the frequency response of the filtering apparatus of the dual-band sensing unit shown in FIG. 4 . This modular embodiment of the dual-band sensing unit is disposed on the filtering apparatus of the present invention.
[0047] There are three curves respectively indicating a main-band coupling curve 501 , a high-band coupling curve 502 and a low-band coupling curve 503 . Since the tunable gain amplifier is used to adjust a suitable gain through the high-band and low-band filtering circuits, the main-band signals won't be influenced as the curve 501 shows. With the frequency becomes higher, the insertion loss varies slightly. Such as the frequencies marked as the points a, b, c, d and e, the point a indicates frequency Xa=2.40 GHz (such as the frequency spectrum of WLAN) and insertion loss Ya=−0.29.
[0048] The curve 502 shows the curve of high-band signals. For filtering the high-band signals, the main-band and low-band signals will be filtered out. The point c shows a transmission zero which is generated by the open stub 41 disposed on the high-band sensing path in FIG. 4 . Therefore, the low-band interference is eliminated since the low-band part, such as the point b, is filtered out.
[0049] Further, a stepped impedance open stub is disposed on the low-band sensing path, thereby to control two or more frequencies of transmission zeros such as the point d (Xd=2.40 GHz, Yd=−48.84) and point e (Xe=5.40 GHz Ye=−41.23) on the low-band coupling curve 503 in FIG. 5 . Based on the requirement, the stepped impedance open stub is adjusted to control two or more positions of the transmission zeros. In the present embodiment, the position of point e can be adjusted in response to high-band interference. In order to determine the frequency spectrum to be filtered out, the distance between the point d and the point e can be adjusted.
[0050] Under the analytic result, not only the adaptive notch filter provided by the preset invention can enhance the flexibility of the filtering apparatus, but also to enhance the performance of main-band signaling because the high-band or low-band signals won't affect the main-band signals. Further, the stepped impedance open stub of the dual-band sensing circuit with transmission zero is arranged to control the two or more frequencies of the transmission zeros for preventing unnecessary frequencies to be coupled. Further, the stepped impedance open stub is also used to control the switch timing of the high-band notch filter and the low-band notch filter precisely. In the meantime, the tunable gain amplifier provides a suitable gain for the voltage comparison by a comparator. After that, the RF switching unit is controlled by controlling the switch timing for each switch.
[0051] FIG. 6 shows a flow chart of the filtering method provided by the mentioned filtering apparatus. In the beginning, the filtering apparatus receives the external signals, especially the signals produced by a variable-frequency subsystem having two or more frequency spectrums (step S 601 ). Next, the dual-band sensing unit performs split frequency to separate the signals into a high-band frequency spectrum and a low-band frequency spectrum. Further, the stepped impedance open stub is arranged with the sensing unit for implementing a tunable filtering (step S 603 ).
[0052] After the process of split frequency, the high-band detecting unit detects the energy of the high-band signals (step S 605 ), and converts the energy into voltage signals (step S 607 ). Similarly, the low-band detecting unit detects the energy of the low-band signals, and converts them into voltage signals.
[0053] Next, the users can control the high-band and low-band parts externally to generate the control signal (step S 611 ). The control signal is inputted to the tunable gain amplifier for adjusting the gain (step S 609 ). Particularly, the control voltage and the suitable gain are arranged based on the interference caused on each system. Next, the comparison operation between the gain amplified voltage and the reference voltage is operated by a comparing unit (step S 613 ). The switch timing for each switch is controlled responsive to the result of comparison operation (step S 615 ). The embodiment of the switches is shown in FIG. 3 .
[0054] The switch timing for each switch is determined by the input signal, and further to control the switch timing of the high-band and low-band notch filters precisely. Afterwards, the notch filter goes to process filtering, that is to activate the high-band or low-band filtering by determining the strength of interference, so as to eliminate the in-band loss (step S 617 ). At last, the signals are sent out via antenna (step S 619 ).
[0055] If the modular dual-band sensing unit provided by the present invention is incorporated with a common RF-related product, only the gain of the tunable gain amplifier needs to be arranged according to the requirement of product. Since the switch timing for each switch of the RF switch unit is controlled according to the comparison operation, the switch timing of the notch filter is further controlled. By means of controlling the RF switching unit, the interference is eliminated effectively for the coexisted variable-frequency subsystem. Most important thing is to prevent the in-band interference or in-system redundant interference.
[0056] While the invention has been described by means of a specification with accompanying drawings of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims.
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A filtering apparatus and method for dual-band sensing circuit are disclosed. The invention features a dual-band sensing unit disposed in a filtering device that receives the signals from a sub-system with variable frequency spectrum. The signals are split up into several bands. After that, one or more frequency detecting units are used to detect the power of high-band and low-band signals, and convert the power into a voltage signal. Users can externally adjust the gain of a tunable gain amplifier for the voltage signal. Further, a comparison operation is processed by a comparator, and a signal resulted from the comparison operation is used to control the switch timing for an RF switching unit. Consequently, this like adaptive notch filter is achieved to determine the intensity of noise and thereby to turn on the high-band or low-band notch filters, so as to reduce the in-band loss.
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This application is a division of application Ser. No. 11/033,092, filed Jan. 10, 2005, now U.S. Pat. No. 7,322,555.
BACKGROUND OF THE INVENTION
The invention relates to a sliding door system for freight elevator landings and, more particularly, to a door suspension system that is easily and quickly installed and adjusted.
PRIOR ART
Horizontal sliding doors for freight elevator landings are typically suspended from overhead tracks. Building codes and good workmanship dictate that the door panels have a limited clearance with the sill plate at the landing floor. Achieving a certain working clearance without exceeding specified limits can be tedious and time-consuming. Typically, a door system is installed by attaching various hardware components to the existing building. Relevant parts of the building are ordinarily of masonry construction and by the nature of such construction, are neither perfectly flat nor regular in hardness and finish. These physical conditions make it difficult for even a skilled installer to initially mount system hardware in a precise location. Prior art arrangements for adjusting the door panels vertically have been less than ideal, requiring, for example, individual adjustment of each door with eccentric roller mounts or use of spacers. Eccentric roller mounts give a non-linear response to adjustment and can throw a panel out of plumb each time one of a pair of rollers is adjusted. Use of spacers, known in the art, is typically troublesome from both a manufacturing standpoint and an installer's perspective. Where door panels in prior art arrangements are individually vertically adjusted, the time required to set all of the panels will ordinarily be proportional to the number of door panels being installed.
SUMMARY OF THE INVENTION
The invention relates to an improved system for suspending horizontal sliding door panels at freight elevator landings that reduces installation time and effort while, at the same time, being simple and economical to manufacture. The system has a vertical adjustment arrangement that facilitates the original installation of the overhead track for the door panels and, additionally, serves to provide for the final vertical adjustment of the door panels. The arrangement, moreover, preferably, uses a screw to raise or lower the track components and door panels with relative ease and with linear, stepless precision.
In the preferred embodiment, the invention includes a plurality of wall mounted brackets that suspend overhead tracks for the sliding door panels. The brackets are situated along the header over the landing opening. The brackets are each initially attached to the wall with an anchor bolt that, besides securing the bracket to the wall, serves as a vertically fixed peg or platform on which the bracket can be jacked up or down. The bracket assembly has a vertically slotted leg and an apertured block which together are assembled on an exposed portion of the installed wall anchor. A jacking screw carried in a threaded hole in the bracket body bears against the block enabling this screw to raise or lower the bracket relative to the anchor with the vertical slot accommodating this motion. Several identical or similar brackets are installed in the same manner along the entrance header to collectively support the tracks from which the door panels are suspended.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a somewhat schematic fragmentary elevational view of a freight elevator landing door assembly as seen from the shaft;
FIG. 2 is a perspective view of the tracks and supporting brackets of the door assembly;
FIG. 3 is a perspective view of a typical track mounting bracket and portions of tracks;
FIG. 4 is a cross-sectional view of a typical bracket taken in the plane 4 - 4 indicated in FIG. 3 ; and
FIG. 5 is a fragmentary cross-sectional view of the door assembly taken in the plane 4 - 4 indicated in FIG. 1 .
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings and in particular to FIG. 1 , there is shown, from the shaft side, a freight elevator landing door installation 10 including a set of four horizontal sliding door panels 11 in a closed position. The door panels 11 protect an opening to the elevator shaft at a landing. The panels 11 are suspended from overhead tracks 13 in a generally conventional manner. Each panel 11 has a pair of associated traction rollers 14 that roll on a horizontal surface 23 ( FIG. 5 ) of a respective track 13 . The rollers 14 of each panel are mounted on a bracket 16 ( FIG. 5 ), a separate bracket being associated with each panel 11 . Preferably, each bracket 16 ( FIG. 5 ) is bolted to the top edge of a respective panel 11 . The door panels 11 in the illustrated case are in pairs, two associated with the left (as viewed in the figures) and two associated with the right. The panels 11 of each pair are in staggered vertical planes with the outer panels adjacent the plane of the shaft or building wall, designated 17 , and the central panels spaced from the wall slightly more than the thickness of the outer panels. The panels 11 can be identical or nearly identical in construction, as desired.
With reference to FIG. 5 , the bottoms of the door panels 11 are guided by gibs 18 . Preferably, a pair of gibs is associated with each panel. The gibs 18 , which are bolted to the panels to enable their replacement, are received in and slide along respective slots 19 in a sill assembly 21 .
The illustrated suspension tracks 13 are fabricated from steel stock into a J-shape with the hook end including a rectangular tube 22 or an equivalent form to provide the horizontal roller support surface 23 . The tracks 13 ( FIG. 4 ) are secured to the underside surfaces 24 of a plurality of bracket assemblies 26 spaced along the header, designated 27 ( FIG. 1 ) of the opening 12 ( FIG. 5 ).
The bracket assemblies 26 ( FIG. 4 ) can be identical (with the exception that the central bracket can have a double set of track mounting slots). A main body 28 of the bracket assembly 26 can be made, preferably, of a single sheet of steel bent and welded into the illustrated shape. The main body includes a vertical leg 31 and a horizontal leg 32 . The lateral edges of the legs 31 , 32 are interconnected by triangular gussets 33 . The top of the bracket 28 has a horizontal web 34 and a downwardly extending reinforcing flange 36 . The web 34 is integral with the vertical leg 31 and the downwardly extending flange is integral with the web. The web 34 and flange 36 , preferably, are welded at their lateral edges to the gussets 33 . A boss 37 is welded or otherwise fixed at a hole 38 in the web 34 centered between the gussets and has a vertical internally threaded bore 39 . A jacking screw 41 in the form of a threaded machine bolt, is assembled in the threaded boss 37 . A vertical slot 42 in the vertical bracket leg 31 is centered between the gussets 33 and a round hole 43 is formed through the vertical bracket leg on a common vertical center line with the slot. Thus, preferably, the slot 42 and hole 43 are symmetrically disposed about a vertical plane perpendicular to the vertical bracket leg 31 and passing through the axis of the jacking screw 41 .
A rectangular block 46 , preferably of steel, is proportioned to slide vertically between the gussets 33 and includes a central hole that aligns with the slot 42 . The block 46 has a thickness sufficient when in contact or near contact with the vertical bracket leg 31 to extend under the jacking screw 41 and, ideally, completely under its diameter to provide a full bearing surface for the end face of the screw. The horizontal bracket leg 32 has a series of slots 47 , each slot overlying a respective one of the tracks 13 . The illustrated brackets 16 are arranged to support three tracks corresponding to a six-panel door. For illustrative purposes, the third track is shown in phantom ( FIG. 3 ).
The door installation 10 ( FIG. 1 ) can be initiated by mounting a sill assembly 21 at the shaft wall 17 at the level of the landing floor with appropriate masonry anchor bolts or other accepted technique. Thereafter, a bracket assembly 26 can be mounted on the shaft wall 17 centered above the door opening a specified distance above the sill assembly 21 . This is accomplished by first drilling a hole in the header area 27 of the wall 17 sized to work with a specified anchor bolt. Thereafter, with an anchor bolt 51 positioned in the drilled hole, designated 52 , the bracket body 28 , block 46 , washers 53 and nut 54 are assembled on the anchor bolt 51 as shown in FIG. 4 . With the first bracket assembly 26 installed, the remaining bracket assemblies 26 can be similarly installed. A recommended procedure to accomplish this task is to use the tracks 13 with factory-installed upstanding threaded studs 55 to laterally locate the remaining bracket assemblies 16 . A first stud 55 is inserted into the proper slot 47 in the central bracket body 28 . The central bracket assembly 28 can be provided with a double set of slots 47 to receive respective studs 55 at the ends of left and right sections of the tracks 13 . The tracks 13 are preliminarily leveled and temporarily held in place with suitable clamps and/or props. Other bracket assemblies 26 are positioned so that appropriate studs 55 are received in their respective slots 47 . Holes 52 are drilled in the shaft wall header 27 at the center of the slots 42 of the additional bracket assemblies 26 and these bracket assemblies are provisionally installed as described for the center bracket assembly. A track spacer plate 56 has holes for receiving and locating the studs 55 , and therefore locating the tracks 13 in a desired spacing relative to one another. A spacer plate is associated with each bracket 26 . Nuts 57 are assembled on upstanding track studs 55 to fasten the tracks 13 to the brackets 26 . The slots 47 permit the tracks 13 to be adjusted horizontally towards and away from the shaft wall 17 as required.
In the illustrated arrangement, as described above, each door panel 11 has an associated hanger or bracket 16 on which is assembled a pair of traction rollers 14 . The hangers or brackets 16 are installed with the rollers on the track support surfaces 23 . With the hangers 16 located on appropriate tracks 13 , the door panels 11 can be bolted onto the hangers. For example, bolts (not shown), assembled vertically through holes in horizontal webs of the hangers 16 can be turned into threaded holes in the upper edges of the door panels 11 to secure the door panels to the hangers. With each door panel 11 secured to a respective hanger 16 , the panels are suspended overhead from the tracks 13 .
The bracket assemblies 26 afford a convenient, accurate and fast way of adjusting a gap 61 ( FIG. 5 ) between the bottom of the door panels 11 and the sill 21 to meet building code requirements and assure smooth opening and closing operation of the door panels. With the nuts 54 slightly loose on the studs of the anchor bolts 51 , the jack screws 41 can be rotated in either direction as needed to raise or lower the tracks 13 and, therefore, the door panels 11 . The jack screws 41 bear against the top surface of their respective blocks 46 thereby transferring the weight of the tracks 13 and door panels 11 to the anchor bolt 51 while allowing the respective bracket assemblies 26 to move vertically within limits of the slots 42 . One or more bracket assemblies 26 are adjusted as necessary. The adjustment mechanism afforded by the jack screw 41 has the desirable characteristic of being linear, lifting or lowering the door panels 11 a distance directly proportional to the angle through which a screw is turned. All of the door panels 11 are adjusted at the same time rather than being adjusted one at a time. When the door panels have been properly adjusted, each of the bracket assemblies 26 can be locked in position by drilling a hole in the building wall header 27 using the hole 43 as a pilot. Thereafter, an anchor bolt 63 , shown in phantom in FIG. 4 , is positioned through the bracket hole 43 into the drilled hole. A nut 64 on this second anchor 63 can then be tightened for additional securement of the bracket assembly 26 . Additionally, the nut 54 associated with the first anchor bolt 51 is fully tightened at this time.
It should be evident that this disclosure is by way of example and that various changes may be made by adding, modifying or eliminating details without departing from the fair scope of the teaching contained in this disclosure. The invention is therefore not limited to particular details of this disclosure except to the extent that the following claims are necessarily so limited.
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A method and apparatus for adjustably mounting tracks that suspend horizontal sliding doors at a freight elevator landing. The apparatus comprises a plurality of brackets adapted to be mounted in the shaft on the header above the landing opening. The brackets are each secured to the header with anchor bolts. Each anchor bolt is set in the header but initially allows vertical movement of the bracket. An adjusting screw, carried on each bracket, is arranged to easily and precisely move the bracket up or down relative to the anchor bolt as needed to position the tracks and, therefore, the door panels at a proper height. Once adjusted such that a specified gap is established between the lower edges of the door panels and the threshold, each anchor bolt can be tightened to fix its respective bracket in its adjusted position.
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CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of my prior utility patent application Ser. No. 08/762,273, filed Dec. 9, 1996, now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to inflatable support structures and more particularly pertains to a new air support apparatus for use in a variety of applications including providing support to a structure.
2. Description of the Prior Art
The use of inflatable support structures is known in the prior art. More specifically, inflatable support structures heretofore devised and utilized are known to consist basically of familiar, expected and obvious structural configurations, notwithstanding the myriad of designs encompassed by the crowded prior art which have been developed for the fulfillment of countless objectives and requirements.
Known prior art inflatable support structures include U.S. Pat. No. 4,901,481; U.S. Pat. No. 5,007,212; U.S. Pat. No. 5,005,322; U.S. Pat. No. Des. 352,328; and U.S. Pat. No. Des. 302,720.
While these devices fulfill their respective, particular objectives and requirements, the aforementioned patents do not disclose a new air support apparatus. The inventive device includes an inflatable tube, a valve for permitting inflation of the inflatable tube, and a flexible mesh in a surrounding relationship with the inflatable tube such that the mesh constrains the shape of the inflatable tube upon its inflation.
In these respects, the air support apparatus according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides an apparatus primarily developed for the purpose of use in a variety of applications including providing support to a structure.
SUMMARY OF THE INVENTION
In view of the foregoing disadvantages inherent in the known types of inflatable support structures now present in the prior art, the present invention provides a new air support apparatus construction wherein the same can be utilized for use in a variety of applications including providing support to a structure.
The general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new air support apparatus apparatus and method which has many of the advantages of the inflatable support structures mentioned heretofore and many novel features that result in a new air support apparatus which is not anticipated, rendered obvious, suggested, or even implied by any of the prior art inflatable support structures, either alone or in any combination thereof.
To attain this, the present invention generally comprises an inflatable tube, a valve for permitting inflation of the inflatable tube, and a flexible mesh in a surrounding relationship with the inflatable tube such that the mesh constrains the shape of the inflatable tube upon its inflation.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
It is therefore an object of the present invention to provide a new air support apparatus apparatus and method which has many of the advantages of the inflatable support structures mentioned heretofore and many novel features that result in a new air support apparatus which is not anticipated, rendered obvious, suggested, or even implied by any of the prior art inflatable support structures, either alone or in any combination thereof.
It is another object of the present invention to provide a new air support apparatus which may be easily and efficiently manufactured and marketed.
It is a further object of the present invention to provide a new air support apparatus which is of a durable and reliable construction.
An even further object of the present invention is to provide a new air support apparatus which is susceptible of a low cost of manufacture with regard to both materials and labor, and which accordingly is then susceptible of low prices of sale to the consuming public, thereby making such air support apparatus economically available to the buying public.
Still yet another object of the present invention is to provide a new air support apparatus which provides in the apparatuses and methods of the prior art some of the advantages thereof, while simultaneously overcoming some of the disadvantages normally associated therewith.
Still another object of the present invention is to provide a new air support apparatus for use in a variety of applications including providing support to a structure.
Yet another object of the present invention is to provide a new air support apparatus which includes an inflatable tube, a valve for permitting inflation of the inflatable tube, and a flexible mesh in a surrounding relationship with the inflatable tube such that the mesh constrains the shape of the inflatable tube upon its inflation.
Still yet another object of the present invention is to provide a new air support apparatus that provides structure.
Even still another object of the present invention is to provide a new air support apparatus that is easily folded for convenient storage.
These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:
FIG. 1 is a plan view of a new Air Support Apparatus according to the present invention.
FIG. 2 is a fragmented view thereof showing the air valve.
FIG. 3 is an fragmented view of the present invention showing the flexible mesh.
FIG. 4 is a plan view of the invention showing a curved tube.
FIG. 5 is a plan view of the invention showing a circular tube.
FIG. 6 is a perspective view of the invention showing a support structure for a tent.
FIG. 7 is a perspective view of the invention showing a support structure for a back pack.
FIG. 8 is a perspective view of the invention showing a child's play pen structure.
DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference now to the drawings, and in particular to FIGS. 1 through 8 thereof, a new Air Support Apparatus embodying the principles and concepts of the present invention and generally designated by the reference numeral 10 will be described.
More specifically, it will be noted that the Air Support Apparatus 10 comprises an inflatable tube 12, a flexible mesh 14 in surrounding relationship with the inflatable tube 12 and a means for inflating the inflatable tube 16.
As best illustrated in FIGS. 1 through 8, it can be shown that the inflatable tube 12, which can be fabricated of rubber or any other suitable material, is surrounded by the flexible mesh 14. The flexible mesh 14 is of strong construction and can be made of any suitable material such as nylon, polyester or rayon. Air enters the inflatable tube 12 by way of the means for inflating the inflatable tube 16, which can include an air valve, and the inflatable tube 12 takes on the shape provided by the flexible mesh 14. Useful shapes include tubes of all shapes such as a curved tube 20 (FIG. 4) and a ring 22 (FIG. 5).
As best illustrated in FIGS. 6-8, the Air Support Apparatus 10 can be used to provide support for a structure such as a tent 24 (FIG. 6) or a back pack 26 (FIG. 7) or provide structure itself as for a child's play pen 28 (FIG. 8).
In use, the inflatable tube 12 is inflated by means of air valve 16. Upon inflation the inflatable tube 12 takes on the shape of the flexible mesh 14 and can be used as a support for a structure or as a structure in and of itself.
With particular reference to FIG. 7, the air support backpack support harness assembly 26 comprises an inflatable back support 30 which is attachable to a bag for carrying on a back. The inflatable back support 30 comprising a plurality of elongate inflatable structures 10 which are arranged in a laterally adjacent series. The support harness assembly 26 also includes a pair of spaced apart inflatable shoulder straps 32, 33. Each of the inflatable shoulder strap has upper and lower ends which are coupled to the inflatable back support 30. Preferably, each of the inflatable shoulder straps 32, 33 comprises a pair of elongate inflatable structures 10 which are arranged in a laterally adjacent series. As mentioned previously, each inflatable structure includes 10, an elongate inflatable tube 12, a flexible mesh 14 surrounding the inflatable tube, and an inflation means 16 for inflating the inflatable tube. Preferably, the inflation means includes a valve which is extended through the inflatable member 12 to provide a selectably closable opening into the interior of the inflatable member 12 to permit inflation and deflation of the inflatable member 12.
With closer reference to FIG. 8, the air support playpen apparatus 28 comprises a generally rectangular floor structure 36 having an outer perimeter. A rectangular lower inflatable rail structure 37 is extended around said outer perimeter of the floor structure 36. A rectangular upper inflatable rail structure 38 is positioned above the lower inflatable guide rail structure 37. The upper inflatable rail structure 38 is spaced apart from the lower inflatable guide rail structure 37. The upper inflatable rail structure 38 is also is aligned with the outer perimeter of the floor structure 36. A plurality of spaced apart inflatable support rail structures 39 are extended between the lower inflatable rail structure 37 and the upper inflatable rail structure 38. Ideally, the floor structure also is inflatable. Like the other devices, the lower inflatable rail structure 37, the upper inflatable rail structure 38, and the inflatable support rail structures 39 all comprise the air support apparatus It) having an elongate inflatable tube 12, an inflation means for inflating the inflatable tube 16, and a flexible mesh 14 surrounding the lower inflatable rail structure, the upper inflatable rail structure, and the inflatable support rail structures. Preferably, like the other structures, each the inflation means includes a valve extending through the inflatable member to provide a selectably closable opening into the interior of the inflatable member to permit inflation and deflation of the inflatable member. In the preferred embodiment of the air support playpen apparatus 28 a flexible mesh 14 surrounds each inflatable tube 12 separately.
With regards to the air support playpen apparatus 28, preferably, of a inflatable support rail structure 39 is extended between the upper inflatable rail structure 38 and the lower inflatable rail structure 37 at each corresponding corner of the upper inflatable rail structure and the lower inflatable rail structure.
As to a further discussion of the manner of usage and operation of the present invention, the same should be apparent from the above description. Accordingly, no further discussion relating to the manner of usage and operation will be provided.
With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.
Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
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A new air support apparatus for use in a variety of applications including providing support to a structure. The inventive device includes an inflatable tube, a valve for permitting inflation of the inflatable tube, and a flexible mesh in a surrounding relationship with the inflatable tube such that the mesh constrains the shape of the inflatable tube upon its inflation.
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FIELD AND BACKGROUND OF THE INVENTION
This invention relates to ready-to-assemble (RTA) furniture, and more particularly, to an RTA clothes hamper.
A clothes hamper of the character described herein generally includes a top, a bottom, and a body assembled to form a relatively large container large enough to hold clothes for one or more washing machine loads of laundry. Due to their relatively large size, prior clothes hampers which are preassembled by a manufacturer are bulky to ship, occupy a great amount of retail store shelf space, and are difficult for the consumer to transport. These factors are particularly important when a "value priced" article is involved.
Some prior RTA clothes hampers (i.e. hampers which are not preassembled by the manufacturer) require the consumer to have tools available for assembly of the hamper. However, the consumer does not always have the necessary tools (or assembly skills) available.
A prior art RTA hamper is known which includes pins for affixing the body of the hamper to the top and the bottom of the hamper. Some prior RTA hampers have recesses (formed by walls) in the top and in the bottom of the hamper for accepting the body of the hamper.
It is therefore a general object of the present invention to provide a ready-to-assemble, aesthetically appealing hamper which, while on display in a store, does not occupy much shelf space and is relatively compact and easy to transport, which does not require tools for assembly, which includes pins that are not visible on the exterior of the hamper and tightly hold the top and the bottom of the hamper to the body of the hamper, and which is easily assembled.
SUMMARY OF THE INVENTION
A ready-to-assemble hamper constructed in accordance with the present invention comprises a bottom frame, a top frame, and a body panel which joins together the top and the bottom frames. Disposed on the bottom frame and on the top frame are panel recesses for accepting the bottom and top edges of the body panel. Each of those panel recesses is formed by an inner wall and an intermediate wall.
At least one of the top and bottom frames is affixed to the body panel by pins which are inserted successively though the inner wall, the body panel, and the intermediate wall and which are not readily visible from the exterior of the assembled hamper.
BRIEF DESCRIPTION OF THE DRAWING
This invention will be better understood from the following detailed description taken in conjunction with the accompanying figures of the drawing, wherein:
FIG. 1 is a perspective view of a ready-to-assemble hamper constructed in accordance with the present invention;
FIG. 2 is an exploded perspective view of the hamper of FIG. 1, in the form of a kit prior to assembly;
FIG. 3 is an elevational view of a top frame taken along line 3--3 of FIG. 2;
FIG. 4 is an elevational view of a bottom frame taken along line 4--4 of FIG. 2;
FIG. 5 is a cross-sectional view of the top frame of FIG. 3 taken along line 5--5 of FIG. 3;
FIG. 6 is an enlarged sectional view of the structure contained in the circle A of FIG. 5, additionally illustrating a cross-sectional portion of a body panel and a pin;
FIG. 7 is a cross-sectional view of the bottom frame of FIG. 4 taken along line 7--7 of FIG. 4;
FIG. 8 is an enlarged sectional view of the structure contained in the circle B of FIG. 7, additionally illustrating a cross-sectional portion of a body panel and a pin;
FIG. 9 is an elevational view of a lid taken along line 9--9 of FIG. 2; and
FIG. 10 is an elevational view of a pin.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows the ready-to-assemble (RTA) hamper 10 after it has been assembled. The hamper 10 is useful for holding, for example, dirty clothes to be washed in one or more washing machine loads of laundry.
FIG. 2 is a perspective view of the hamper 10 prior to its assembly (e.g., in kit form). When sold as a kit, the components forming the hamper 10 can be compactly boxed for inventory storage and for shipment from the manufacturer to the retail store. At the retail store, at least three of the hamper 10 kits can be displayed in the shelf space otherwise occupied by one assembled hamper. Additionally, when packaged as a RTA kit, the hamper 10 can be readily transported by the purchaser of the kit.
With reference to FIGS. 1 and 2, the hamper 10 comprises a top frame 12, a bottom frame 14, a body panel 16, a lid 18, a back seam extrusion 20 and pins 22. The top frame 12, the bottom frame 14, and the lid 18, are preferably manufactured by an injection molding process. The pins 22 are preferably formed of plastic.
The body panel 16 includes a top edge 24, a bottom edge 26, two vertical side edges 28, and holes 30 disposed through the body panel 16 adjacent the top and bottom edges.
The body panel 16 preferably has a two-layer construction and comprises of a support layer 32 and a decorative outer layer 34. The support layer 32 may be formed from chipboard or other stiff, supportive material. Because the shape and the structural integrity of the hamper 10 depend substantially from the body panel, it is important to construct the support layer 32 from a suitably strong material. The decorative layer 34 may be formed, for example, from inter-woven strips of tissue-like paper (which may be coated to add strength and to make the decorative layer easier to clean) or from any of a variety of types of cloth or fabric.
Also illustrated in FIG. 2 is the back seam extrusion 20 which includes two back seam extrusion recesses 36 along its long edges. The recesses 36 extend along the vertical side edges of the extrusion 20 and are sized and configured to accept and cover the vertical side edges 28 of the body panel 16.
As illustrated in FIGS. 3, 5, and 6, the top frame 12 is formed by a substantially continuous strip having a generally rectangular configuration, the top frame 12 being open at the center. The strip includes a panel recess 40 formed between an inner wall 42 and an intermediate wall 44. The inner wall 42 and the intermediate wall 44 are adjacent walls, each having a generally rectangular (four-sided) configuration (see FIG. 3). The panel recess 40 of the top frame 12 is sized and configured to accept the top edge 24 of the body panel 16.
As shown in FIGS. 5 and 6, the intermediate wall 44 of the top frame 12 has a top edge 46 which is generally inclined toward the inner wall 42 of the top frame 12, and the inner wall 42 of the top frame 12 is taller than the intermediate wall 44 of top frame 12. Both the angle of the top edge 46 of the intermediate wall 44 and the height of the inner wall 42 of the top frame 12 relative to the height of the intermediate wall 44 of the top frame 12 allow for the top edge 24 of the body panel 16 to be readily and easily inserted into the panel recess 40 of the top frame 12. Specifically, when so inserting the top edge 24 of the body panel 16 into the panel recess 40 of the top frame 12, the top edge 24 is first guided into the panel recess 40 by abutting the top edge 24 against the inner wall 42 of the top frame 12 and by sliding the top edge 24 toward and into the panel recess 40. Then, as the body panel 16 reaches and abuts the angled top edge 46 of the intermediate wall 44 of the top frame 12, the angled top edge 46 further guides the body panel 16 into the panel recess 40.
As illustrated in FIGS. 2, 5, and 6, disposed on the inner wall 42 of top frame 12 are holes 50. In the specific example of the invention described herein, two holes 50 are disposed on each of the four sides of the inner wall 42. Each hole 50 is disposed such that it is aligned with one of the holes 30 of the body panel 16 (FIG. 2) when the parts are assembled.
As illustrated in FIG. 6, disposed on the intermediate wall 44 of top frame 12 are holes 52. Two holes 52 are disposed on each of the four sides of the intermediate wall 44. Each hole 52 is disposed such that it is aligned with one of the holes 50 and with one of the holes 30 of the body panel 16. When the holes 50, the holes 30, and the holes 52 are so aligned, the pins 22 may be inserted successively through the holes 50, the holes 30 and the holes 52 from the interior of the top frame 12.
The holes 50, 52 and 30 are sized and configured to accept and to securely hold the pins 22. As illustrated in FIG. 10, each of the pins 22 is made of a relatively stiff plastic and includes a pin shaft 54 and angular flanges or fins 56. Such pins are commercially available. The flanges 56 are sized and configured to hold the pins 22 tightly in the holes 50, 52, and 30. The diameter of the holes 50, 52, and 30 is slightly less than the diameter of the flanges 56, and consequently when the pins 22 are so inserted, the flanges 56 bend away from the direction of insertion and thereby securely and reliably join together the top frame 12 and the body panel 16. However, the pins 22 can be removed and the hamper 10 knocked-down (i.e., disassembled) for transport or storage.
FIGS. 2, 3, 5, and 6 also illustrate an outer wall 60 of the top frame 12. The pin shafts 54 of the pins 22 are dimensioned (in their length) such that when the pins 22 are inserted successively through the holes 50, the holes 30, and the holes 52, the pins 22 stop short of the outer wall 60 (see FIG. 6). Thus, the hamper 10 is aesthetically appealing because the pins 22 are hidden from view from the exterior of the top frame 12, by the wall 60.
FIGS. 2 and 9 illustrate the lid 18 of the hamper 10 which is sized to cover the center opening in the top frame 12. The lid has a generally rectangular shape, and disposed on the lid 18 are two lid pins 62 for hingedly connecting the lid 18 to the top frame 12. Shown in FIGS. 2 and 3 are two lid pin holes 64 disposed in the inner wall 42 of the top frame 12 for hingedly connecting to and accepting the lid pins 62 of the lid 18. The body panel 16 includes two notches 66 (see FIG. 2) which are aligned with the lid pins holes 64 and which are sized to allow the lid pins 62 to pass therethrough. The plastic lid has sufficient flexibility that it may be flexed or bowed slightly to enable the pins 62 to be inserted into the holes 64.
As illustrated in FIGS. 4, 7, and 8, the bottom frame 14 includes a panel recess 70 formed between an inner wall 72 and an intermediate wall 74. The inner wall 72 and the intermediate wall 74 are adjacent walls, each having a generally rectangular (four-sided) configuration (see FIG. 4). The panel recess 70 of the bottom frame 14 is sized and configured to accept the bottom edge 26 of the body panel 16.
As shown in FIGS. 7 and 8, the inner wall 72 of the bottom frame 14 is taller than the intermediate wall 74 of bottom frame 14. The height of the inner wall 72 relative to the height of the intermediate wall 74 allows for the bottom edge 26 of the body panel 16 to be readily and easily inserted into the panel recess 70 of the bottom frame 14. Specifically, when so inserting the bottom edge 26 of the body panel 16 into the panel recess 70, the bottom edge 26 is guided into the panel recess 70 by abutting the bottom edge 26 against the inner wall 72 of the bottom frame 14 and by sliding the bottom edge 26 against the inner wall 72 and into the panel recess 70.
As illustrated in FIGS. 7 and 8, disposed on the inner wall 72 of bottom frame 14 are holes 76. Two holes 76 are disposed on each of the four sides of the inner wall 72. Each hole 76 of the inner wall 72 of the bottom frame 14 is disposed such that it is aligned with one of the holes 30 of the body panel 16 (FIG. 2) when the parts are assembled.
As illustrated in FIG. 8 disposed on the intermediate wall 74 of bottom frame 14 are holes 78. Two holes 78 are disposed on each of the four sides of the intermediate wall 74. Each hole 78 of the intermediate wall 74 of the bottom frame 14 is disposed such that it is aligned with one of the holes 76 of the inner wall 72 of the bottom frame 14 and with one of the holes 30 of the body panel 16. When the holes 76, the holes 30, and the holes 78 are so aligned, the pins 22 may be inserted successively through the holes 76, the holes 30, and the holes 78 from the interior of the bottom frame 14.
The holes 76 of the inner wall 72 of the bottom frame 14, the holes 78 of the intermediate wall 74, and the holes 30 of the body panel 16 are sized and configured to accept and to securely hold the pins 22, similarly to the attachment of the pins at the top frame 12.
FIGS. 4, 7, and 8 also illustrate an outer wall 80 of the bottom frame 14. The pin shaft 54 of the pins 22 is dimensioned (in its length) such that when the pins 22 are inserted successively through the holes 76, the holes 30, and the holes 78, the pins 22 will not project through the outer wall 80 of the bottom frame 14. Thus, the hamper 10 is aesthetically pleasing because the pins 22 are not visible on either the exterior of the bottom frame 14 or on the exterior of the top frame 12.
Also illustrated in FIGS. 2 and 4 are a plurality of openings 82 which form air vents in the bottom frame 14. Shown in FIGS. 2, 7, and 8 are feet 84 of the bottom frame 14, which elevate the hamper 10 above a support surface (e.g., the floor) and allow air to circulate under the hamper and through the openings 82.
As can be understood from the above description of the invention and as set forth hereinafter, the hamper 10 can be assembled without the use of tools.
As illustrated in FIG. 2, the body panel 16 of the hamper 10 is folded along four lines f--f, g--g, h--h, and i--i to form a rectangular shape and the panel 16 is preferably precreased at the four corners to facilitate the folding. Once folded, the top edge 24 of the body panel 16 has the same approximate configuration as the panel recess 40 of the top frame 12 and the bottom edge 26 of the body panel 16 has the same approximate configuration as the panel recesses 70 of the bottom frame 14. The top edge 24 of the body panel 16 is then inserted into the panel recess 40 of the top frame 12.
The back seam extrusion 20 of the hamper 10 is then positioned with the two vertical side edges 28 of the body panel 16 in the recesses 36. Thus, the back seam extrusion 20 of the hamper 10 covers the vertical side edges 28 of the body panel 16.
In an alternative embodiment of the present invention, prior to assembly of the hamper 10, one of the back seam extrusion recesses 36 of the back seam extrusion 20 is secured(e.g., glued by the manufacturer) to one of the vertical side edges 28 of the body panel 16. In this embodiment, beginning at the vertical side edge 28 which has been fixed to the back seam extrusion 20, the top edge 24 of the body panel 16 is walked-around (i.e., inserted into) the panel recess 40 of the top frame 12. Then, the other vertical side edge 28 of the body panel 16 is inserted into the other back seam extrusion recess 36 of the back seam extrusion 20.
After the back seam extrusion 20 is joined to the body panel 16, the bottom edge 26 of the body panel 16 is inserted into the panel recess 70 of the bottom frame 14. Then, the pins 22 are pushed successively through the holes 50 of the inner wall 42 of the top frame 12, the holes 30 of the body panel 16, and the holes 52 of the intermediate wall 44 of the top frame 12. Others of the pins 22 are pushed successively through the holes 76 of the inner wall 72 of the bottom frame 14, the holes 30 of the body panel 16, and the holes 78 of the intermediate wall 74 of the bottom frame 14.
The last assembly step includes positioning the lid 18 so that one of the lid pins 62 of the lid 18 can be inserted through one of the lid pin holes 64 of the top frame 12 and through one of the notches 66 of the body panel 16, and then flexing the lid so that the other one of the lid pins 62 can be inserted through the other one of the lid pin holes 64 and through the other one of the notches 66. Thus positioned, the lid 18 hingedly connected to and will cover the center opening of the top frame 12.
Obviously, modifications and variations of the present invention are possible in light of the above teachings. Thus, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than is specifically set forth above.
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This disclosure relates to a ready-to-assemble hamper which includes a bottom frame, a top frame, and a body panel which joins together the top and the bottom frames. Disposed on the bottom frame and on the top frame are panel recesses for accepting the body panel. Each of the panel recesses is formed by an inner wall and an intermediate wall. The top and bottom frames each are affixed to the body panel by pins which are inserted successively though its inner wall, the body panel, and its intermediate wall and which are not readily visible on the assembled hamper as they are covered by outer walls on the top frame and on the bottom frame.
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BACKGROUND
This invention relates generally to access management and control systems, and more particularly, the present invention relates to a method, system, and storage medium for managing access to job-specific information, applications, and physical locations.
Virtually every business in operation today utilizes some form of security system to protect the integrity of its buildings and structures, as well as its proprietary and confidential data. For many businesses, security is considered to the single most important objective. Safeguarding these assets, however, can be an enormous task, particularly for large entities.
Various tools have been developed to address these concerns. For example, security badges may be issued for controlling access to specified facilities, parking lots, entrance ways, offices, etc. Employee password accounts limit access to computers and applications based upon position and job-specific criteria. Confidential records, whether stored on a computer disk or in a file cabinet folder are secured through these password designations and/or by locks on office doors.
While many of these tools may be suitable for a specific purpose, they alone cannot address the varying and complex security needs of most larger businesses today. For example, password access tools may be inefficient for businesses that experience significant (or even average) turnover in personnel. As new employees are hired to replace retired, transferred, terminated employees, or simply to fill new positions of a growing business, a system must be able to handle these changes or the security of the business may be jeopardized. The problem is compounded when considering the ripple effect caused by changes in personnel. Human resources, IT, physical security, management, etc., are some of the departments affected by these changes. For example, an employee directory must be continuously modified to reflect personnel changes, a human resources department must modify and update employee files, and a system administrator must do likewise for computer accounts. Further, physical security must be addressed in accordance with the business' procedures which may include changing locks, issuing/retrieving employee badges, keycards, etc. The same or similar processes would take place for employee transfers, promotions, or similar change in personnel. Modification of management and supervisory assignments must also be updated to reflect changes in employment status.
Currently, these procedures and authorizations are done individually with separate forms stored on different systems which are transmitted from location to location for approval and administrative processing. The affected employees may be required to track the progress of the forms. It is not uncommon to find an ex-employee's name on the company directory months after termination. For the same reasons set forth above, it is no surprise that auditing these disjunct processes can also be problematic for the business.
It is, therefore, desirable to provide a means for managing access and control to job-specific information, applications, and physical locations associated with a business enterprise.
BRIEF SUMMARY
An exemplary embodiment of the invention relates to a method, system, and storage medium for managing access to job-specific information, applications, and physical locations. The system includes a network server in communication with client systems, and further includes: a database of employee records and a database of job code records both accessible to at least one of the client systems via the network server; an employee directory database including employee names and employee contact information; and an access management tool executable by the server. The access management tool processes changes to access requirements, updates respective databases, and transmits notices to designated client systems. The invention also includes a method and a storage medium.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring now to the drawings wherein like elements are numbered alike in the several FIGURES:
FIG. 1 is a block diagram of computer network system in which the access management tool is implemented in a preferred embodiment of the invention;
FIG. 2 is a computer screen window illustrating a sample employee record created by the access management tool;
FIG. 3 is a computer screen window illustrating a sample job code record; and
FIG. 4 is a flowchart describing the process of implementing the access management tool in an exemplary embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In an exemplary embodiment, the access management tool is implemented via a networked system such as that depicted in FIG. 1 . Although not necessary to realize the advantages of the present invention, system 100 may be part of a wide area network in which different geographical locations are interconnected, either by high-speed data lines or by radio links, interconnecting hundreds of workstations at widely disparate locations. In the simplified diagram of FIG. 1 , system 100 represents a business enterprise comprising a server 102 , client systems 104 - 112 and databases 120 - 124 each in communication via a network 130 . Network 130 may comprise a LAN, a WAN, or other network configuration known in the art. Further, network 130 may include wireless connections, radio-based communications, telephony-based communications, and other network-based communications. For purposes of illustration, however, network 130 is a LAN.
For purposes of illustration, system 100 is running Lotus Domino (™) as its server software. Server 102 executes the access management tool, among other applications utilized by system 100 . Server 102 is also running a groupware application such as Lotus Notes (™) which supports replication capabilities and provides e-mail services.
Groupware applications are well known to those skilled in the art and include email, messaging, calendaring, and a host of multi-media tools. Likewise, client systems of server 102 employ suitable client-side applications for facilitating the groupware tools utilized by server 102 such as web browser programs and email software. Server 102 also executes application software used by the access management tool including database management software such as IBM's DB2 (™).
Server 102 provides access and other related services to employees of system 100 such password administration, human resources administration, physical security assistance as well as other services. Server 102 also retrieves data stored therein for use by authorized client systems of system 100 . A data storage device 118 resides within network 130 and may comprise any form of mass storage configured to read and write database type data maintained in a file store (e.g., a magnetic disk data storage device). Data storage device 118 is logically addressable across a distributed environment such as a system 100 . The implementation of local and wide-area database management systems to achieve the functionality of data storage device 118 will be readily understood by those skilled in the art. Information stored in data storage device 118 is retrieved and manipulated via server 102 .
Server 102 may be connected to an external network (e.g., Internet) in order to facilitate communications with outside entities and may extend the services provided by the access management tool to its remote offices, subsidiaries, etc.
Client systems 104 - 112 represent computer processing devices such as a general-purpose desktop computer or similar device. Client systems 104 - 112 are in communication with server 102 via network 130 .
Client system 104 is operated by a lower level employee of system 100 . Users of client system 104 are typically granted limited access to system resources such as word processing applications, e-mail, and job-specific software necessary in order for users to perform their jobs.
Client system 106 is operated by a supervisor or manager of the employee operating client system 104 . Users of client system 106 are typically granted extended access to system resources beyond that which are granted to users of client system 104 . Users of client system 106 may be given access to employee records for personnel under their charge in order to perform access management and/or auditing via the access management tool as will be described further herein.
Client system 108 is operated by a human resources representative charged with the administration of employee records. In a preferred embodiment, users of client system 108 have superior access to employee records in order to facilitate processing of new hires, transfers, terminations, etc. Human resources personnel of system 100 may also employ commercial applications to facilitate implementation of the access management tool such as IBM's HRAccess®.
Client system 110 is operated by a system administrator of system 100 who is charged with maintaining network 130 and its applications. The system administrator performs various other functions such as creating and maintaining password accounts for employees of system 100 .
System 100 further includes client system 112 which may be operated by a security manager of system 100 . A security manager is charged with the physical security of the building(s) of system 100 in terms of monitoring entranceways, external grounds, parking lots, as well as the internal office spaces. For organizations that issue badges for controlling physical access, the security manager or department would have access to information necessary to implement the security plan set in place by the business.
It will be understood that any number of client systems may be used by system 100 in order to realize the advantages of the invention. Further, the access levels granted as described above with respect to client systems' 104 - 112 access to network information may include ‘read only’ access restrictions if desired by the business enterprise.
Server 102 utilizes databases 120 - 124 provided by system 100 and executes the access management tool of the invention. Databases include an employee record database 120 , a job code database 122 , and a directory database 124 . Employee record database 120 stores a variety of information pertaining to each employee of system 100 . A sample employee record 200 is displayed in FIG. 2 for illustrative purposes. Employee record 200 contains the employee's name, address, phone number, business e-mail address, and other personal data (not shown) such as social security number and birth date 202 . Employee record 200 also includes an identification number in ID field 204 which uniquely identifies the employee. Record 200 further includes an employee job code field 206 which has been established for the position for which the employee has been hired. Job codes are further described in FIG. 3 . A job location field 208 is provided and may be optionally utilized in addition to job code field 206 for further specifying an employee's position. For example, in large organizations with multiple facilities, Job codes may be further specified according to geographic location.
Record 200 preferably includes information fields for further defining an employee's status within system 100 . Information fields include date of hire 210 , transfer field 212 , promotion field 214 , and termination field 216 . These can be used for auditing purposes as well as general administrative purposes as will be described further in FIG. 4 .
Information stored in record 200 , as well as employee records database 120 , is accessible to authorized client systems of system 100 as described herein.
Job code database 122 stores information relating to the various job positions available with respect to system 100 . For example, job titles such as administrative clerk, mail clerk, lab technician, department manager, etc. would each have a designated job code. A job code may comprise any alphanumeric character string adopted by system 100 . A sample job code record is illustrated in FIG. 3 for illustrative purposes. A user with permissions accesses job code record 300 via the access management tool by entering a job code A19 (and optionally a job location) where indicated by the tool and the job code record 300 is presented. A description of the job is provided in record 300 as well. Other information that may be provided in job code record 300 include a training link 302 , a link to a listing of applications available for this job code 304 , physical access permissions 306 , and any other information desired by system 100 . For example, a user selects ‘training’ and is directed to a library of course materials, references, relevant job-specific manuals, etc. designed for the designated job code.
Database 124 contains a listing of all of the employees of system 100 and related contact information such as email addresses.
Whenever changes affecting access occur, relevant information can be provided via the access management tool, and replicated at scheduled time intervals. Additionally, server 102 may be programmed to systematically conduct scheduled replications, whereby database replicas are temporarily stored in a queue awaiting replication (not shown). Replications may be scheduled by system 100 as frequently as desired in order to provide access to the most current, up-to-date information.
FIG. 4 illustrates the process for creating a new employee record utilized by the access management tool in a preferred embodiment of the invention. A newly-hired employee may be required to show a badge before an orientation session and/or before being permitted access to the employer's facilities. In this situation, the process begins at step 400 whereby the employee is issued a badge. Badge security systems typically include a photograph of the employee and an identification number uniquely assigned to that employee. Other information may be included on the badge as well. The employee is then permitted physical access to a location for further processing. If a badge security system or similar type of security system is not in place, the process described in FIG. 4 would alternatively begin at step 402 as described herein.
A human resources representative, or other authorized person charged with the administration of newly hired employees (also referred to as ‘user’) logs on to the access management tool at step 402 . A menu of options is presented at step 404 . Such options may include creating a new record, editing an existing record, viewing one or more records, and establishing an audit schedule.
The user selects ‘create new record’ at step 406 and either enters an ID 204 for the employee or an ID 204 is automatically created by the tool at step 408 . For employers utilizing a badge security system, the ID provided on the badge may be used for this step. The user then enters the personal information 202 at step 410 . A job code 206 (and optionally a job location 208 ) is entered at step 412 . Other information may be provided by the user while creating the record as desired. Once the information has been entered, the user saves the record at step 414 . Saving the record causes a copy of the information to be stored in employee record database 120 at step 416 . Further, the company directory database 124 may be automatically updated to include selected information on the record at step 418 . Finally, automatic notifications are sent to the manager assigned to the job code, the IT representative, and physical security manager at steps 420 , 422 , and 424 , respectively. These notifications may be by e-mail or other communication means.
Once a manager receives the notification, he/she is instructed by the tool to ‘enable’ the applications necessary for the employee of that job code at step 426 and any additional applications that may be necessary. The IT representative is instructed by the tool to establish a password account for the employee at step 428 . The physical security manager is instructed by the tool to authorize physical access in order for the employee to gain access to offices, laboratories, libraries, conference rooms, etc. at step 430 .
During the establishment of the new record, the human resources representative may also create an audit schedule for the record. This can be accomplished by flagging any or all of fields 212 - 216 to send an alert to selected recipients upon modification of these fields. For example, suppose the employee listed in record 200 is promoted to Lab Tech, Level 2 within the same department. The modification to field 214 causes an alert to be transmitted to the manager for the new job code assigned (which in this case, is the same manager), IT department, physical security manager, and any entities designated by the tool to receive this information. Any instructions for updating this new information would follow as described above. Reminder notices may be sent to these entities if desired where there has been a failure to act in accordance with the instructions provided. Automatic auditing procedures may also be established. For example, a human resources representative can flag a job code for auditing activities to be conducted twice a year in order to verify continuing access requirements and the employment status of employees in that job code. Other criteria for selecting an audit can be determined as desired such as by department, facility, etc.
As described above, the present invention can be embodied in the form of computer-implemented processes and apparatuses for practicing those processes. The present invention can also be embodied in the form of computer program code containing instructions embodied in tangible media, such as floppy diskettes, CD-ROMs, hard drives, or any other computer-readable storage medium, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes an apparatus for practicing the invention. The present invention can also be embodied in the form of computer program code, for example, whether stored in a storage medium, loaded into and/or executed by a computer, or transmitted over some transmission medium, such as over electrical wiring or cabling, through fiber optics, or via electromagnetic radiation, wherein, when the computer program code is loaded into and executed by a computer, the computer becomes an apparatus for practicing the invention. When implemented on a general-purpose microprocessor, the computer program code segments configure the microprocessor to create specific logic circuits.
While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustration and not limitation.
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An exemplary embodiment of the invention relates to a method, system, and storage medium for managing access to job-specific information, applications, and physical locations. The system includes a network server in communication with client systems, and further includes: a database of employee records and a database of job code records both accessible to at least one of the client systems via the network server; an employee directory database including employee names and employee contact information; and an access management tool executable by the server. The access management tool processes changes to access requirements, updates respective databases, and transmits notices to designated client systems. The invention also includes a method and a storage medium.
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This is a Division of application Ser. No. 08/419,979 now U.S. Pat. No. 5,552,231, filed Apr. 11, 1995 which is a file wrapper continuation application of parent application Ser. No. 08/046,834 filed Apr. 13, 1993 now abandoned.
BACKGROUND OF THE INVENTION
In the printing field, the impact type printer has been the predominant apparatus for providing increased throughput of printed information. The impact printers have included the dot matrix type wherein individual print wires are driven from a home position to a printing position by individual and separate drivers. The impact printers also have included the full character type wherein individual type elements are caused to be driven against a ribbon and paper or like record media adjacent and in contact with a platen.
The typical and well-known arrangement in a printing operation provides for transfer of a portion of the ink from the ribbon to result in a mark or image on the paper. Another arrangement includes the use of carbonless paper wherein the impact from a print wire or a type element causes rupture of encapsulated material for marking the paper. Also known are printing inks which contain magnetic particles wherein certain of the particles are transferred to the record media for encoding characters in manner and fashion so as to be machine readable in a subsequent operation. One of the known encoding systems is MICR (Magnetic Ink Character Recognition) utilizing the manner of operation as just mentioned.
While the impact printing method has dominated the industry, one disadvantage of this type of printing is the noise level which is attained during printing operation. Many efforts have been made to reduce the high noise levels by use of sound absorbing or cushioning materials or by isolating the printing apparatus.
More recently, the advent of thermal printing which effectively and significantly reduces the noise levels has brought about the requirements for heating of extremely precise areas of the record media by use of relatively low energy, thin film resistors or like thermal print head elements. The intense heating of the individually isolated elements causes transfer of coating material from a coated medium onto paper or like receiving substrate. Alternatively, the paper may be of the thermal type which includes materials that are responsive to the generated heat.
The use of thermal transfer printing, especially when performing a subsequent sorting operation, can result in smearing or smudging adjacent the printed symbols or digits on the receiving substrate. This smearing can make character recognition, such as OCR (Optical Character Recognition) or MICR (Magnetic Ink Character Recognition), difficult and sometimes impossible. Additionally, the surface of the receiving substrate and the printed symbols or digits are subject to scratching which can result in blurred images and also result in incorrect reading of the characters. Further, it has been found that certain transfers of coating material from the coated medium to the receiving substrate resulted in ill-defined and non-precise or blurred images.
In the case of previous or prior art formulations used in thermal printing technology and still in use today, solvent or hot melt systems involve the use of temperatures of 150-300 degrees F. The hot melt process uses waxes and resins along with pigments which are formulated at temperatures of 150-300 degrees F. The solvent process uses volatile solvents incorporating waxes, resins and pigments which are formulated at temperatures of 150-170 degrees F. However, there is an environmental problem with disposal of excess materials when using these processes.
Still more recently, the environment has become a controversial issue in the matter of awareness and protection of certain areas, and means are being implemented to protect such areas. One of the means for protecting the environment is reducing the emissions of volatile organic compounds (VOC) in manufacturing processes. In this regard, it is expected that the use of synthetic solvents will be eliminated or substantially reduced within a few years.
In view of these environmental issues and the conditions associated therewith, the present invention has resulted in a thermal transfer medium in the preferred form of a ribbon which eliminates or substantially reduces smearing or smudging and scratching across or adjacent the printed digits or symbols during sorting or other operations, and the ribbon is made of materials that are acceptable by the industry for environmental protection.
Hundreds of formulations and many more compounds were used in water base experimental operations to find an optimum coating for use in thermal printing technology that is environmentally acceptable. The present invention uses water and a small amount of volatile solvent to create a coating that is acceptable, the solvent being included for proper rheological control.
Representative documentation in the area of nonimpact printing includes U.S. Pat. No. 3,663,278, issued to J. H. Blose et al. on May 16, 1972, which discloses a thermal transfer medium having a coating composition of cellulosic polymer, thermoplastic resin, plasticizer and a sensible dye or oxide pigment material.
U.S. Pat. No. 4,315,643, issued to Y. Tokunaga et al. on Feb. 16, 1982, discloses a thermal transfer element comprising a foundation, a color developing layer and a hot melt ink layer. The ink layer includes heat conductive material and a solid wax as a binder material.
U.S. Pat. No. 4,343,494, issued to G. H. Ehrhardt et al. on Aug. 10, 1982, discloses a carbonless copy paper with a hot melt coating on one surface and an image receptor coating on the other surface.
U.S. Pat. No. 4,347,282, issued to G. H. Ehrhardt et al. on Aug. 31, 1982, discloses a chemical carbonless copy paper with a hot melt coating.
U.S. Pat. No. 4,403,224, issued to R. C. Wironwski on Sep. 6, 1983, discloses a surface recording layer comprising a resin binder, a pigment and a smudge inhibitor dispersed in the binder.
U.S. Pat. No. 4,463,034, issued to Y. Tokunaga et al. on Jul. 31, 1984, discloses a heat sensitive magnetic transfer element having a hot melt or a solvent coating.
U.S. Pat. No. 4,523,207, issued to M. W. Lewis et al. on Jun. 11, 1985, discloses a thermal record sheet which uses crystal violet lactone and a phenolic resin.
U.S. Pat. No. 4,592,954, issued to S. L. Malhotra on Jun. 3, 1986, discloses a transparency for ink jet printing and having a substrate and a coating consisting essentially of a blend of carboxymethyl cellulose and polyethylene oxides.
U.S. Pat. No. 4,628,000, issued to S. G. Talvalkar et al. on Dec. 9, 1986, discloses a thermal transfer formulation that includes an adhesive-plasticizer or transfer agent and a coloring material or pigment.
U.S. Pat. No. 4,651,177, issued to S. M. Morishita et al. on Mar. 17, 1987, discloses a thermal transfer recording material having a heat-meltable ink layer comprising a dye or pigment, a binder and a wax which are coated on a support as an aqueous solution and/or an aqueous emulsion.
U.S. Pat. No. 4,687,701, issued to F. Knirsch et al. on Aug. 18, 1987, discloses a heat-sensitive inked element using a blend of thermoplastic resins and waxes.
U.S. Pat. No. 4,688,057, issued to S. Ueyama on Aug. 18, 1987, discloses a heat-sensitive transferring recording medium with an ink layer consisting essentially of three waxes of different values, an extender pigment and a coloring agent.
U.S. Pat. No. 4,707,395, issued to S. Ueyama et al. on Nov. 17, 1987, discloses a substrate, a heat-sensitive releasing layer, a coloring agent layer, and a heat-sensitive cohesive layer.
U.S. Pat. No. 4,777,079, issued to M. Nagamoto et al. on Oct. 11, 1988, discloses an image transfer type thermosensitive recording medium using thermosoftening resins and a coloring agent.
U.S. Pat. No. 4,778,729, issued to A. Mizobuchi on Oct. 18, 1988, discloses a heat transfer sheet having a hot melt ink layer on one surface of a film and a filling layer laminated on the ink layer.
U.S. Pat. No. 4,792,495, issued to M. Taniguchi et al. on Dec. 20, 1988, discloses a fusible ink sheet having a top layer of carnauba wax, montan wax or paraffin wax and ethylene vinyl acetate copolymer on a color layer.
U.S. Pat. No. 4,882,218, issued to K. Koshizuka et al. on Nov. 21, 1989, discloses a thermal transfer recording medium having two heat softening layers each containing a polyoxyethylated compound.
U.S. Pat. No. 4,956,225, issued to S. L. Malhotra on Sep. 11, 1990, discloses a transparency suitable for imaging and having a polymeric substrate with a toner receptive coating on one surface and which coating is comprised of blends selected from the group consisting of polyethylene oxide, carboxymethyl cellulose and hydroxypropyl cellulose.
U.S. Pat. No. 5,021,291, issued to T. Kobayashi et al. on Jun. 4, 1991, discloses an ink-bearing medium comprising a water-soluble resin containing polyvinyl alcohol, a fusible ink material containing a solid fatty acid, a coloring agent, and a fusible agent.
U.S. Pat. No. 5,045,383, issued to M. Maeda et al. on Sep. 3, 1991, discloses a thermosensitive image transfer recording medium comprising a support, a release layer having an unvulanized rubber and a thermofusible wax component and a thermofusible ink layer having a coloring agent and a thermofusible resin component.
And, U.S. Pat. No. 5,128,308, issued to S. G. Talvalkar on Jul. 7, 1992, discloses a thermal transfer ribbon comprising a substrate, a first coating thereon containing water-based ingredients which are thermally reactive for creating color images, the ingredients being a leuco dye and a phenolic resin, and a second coating containing solvent-based ingredients which are thermally active for transferring the color images.
SUMMARY OF THE INVENTION
The present invention relates to nonimpact printing. More particularly, the invention provides a coating formulation or composition for a thermal ribbon or transfer medium for use in imaging or encoding characters on paper or like record media documents which enable machine, or human, or reflectance reading of the imaged or encoded characters. The thermal transfer ribbon enables printing in a quiet and efficient manner and makes use of the advantages of thermal printing on documents with a signal inducible ink.
Since the transferred digits or symbols, which are created by means of thermal transfer technology, in effect, "sit" on the surface of the paper or media, a smearing of the ink of the digits or symbols or a scratching of the surface of the paper or media is of major concern in the course of the document sorting operation.
In accordance with the present invention, there is provided a thermal transfer ribbon comprising a substrate, and a coating on the substrate and containing essential ingredients which are water based and are thermally active for thermally transferring color images onto an image receiving medium upon application of heat to the coating of the ribbon, the thermally active ingredients comprising a solution of poly(ethylene oxide) resin, casein, high density polyethylene and carnauba wax, the ingredients being solubilized or emulsified in a mixture of about 10 percent volatile solvent and about 90 percent water.
The ribbon comprises a thin, smooth substrate such as tissue-type paper or polyester-type plastic on which is applied a layer or coating that is thermally active for transferring the color images, upon application of heat to the ribbon, onto an image receiving medium. The thermally active ingredients are mixed or dispersed in a solution or emulsion and then the mixture is ground to form extremely fine particles in an attritor or other conventional dispersing equipment. Coloring pigments, dyes or like sensible materials may include carbon black for use in thermal transfer ribbons or may include magnetic sensible materials for use in magnetic thermal transfer ribbons. The thermal transfer coating is then applied to the substrate by well-known or conventional coating techniques.
The coating or layer of the present invention is provided to substantially reduce or eliminate image smearing, smudging or scratching of a transferred and printed image when using a nonmagnetic or a magnetic thermal transfer ribbon. The coating is predominately water based and includes poly(ethylene oxide) resin and casein along with a wax emulsion and pigment or dye material. The coating is formulated at room temperatures in the range from 65 to 80 degrees F.
In view of the above discussion, a principal object of the present invention is to provide a ribbon which includes a thermal-responsive coating.
Another object of the present invention is to provide a thermal transfer ribbon substrate including a coating thereon for use in imaging or encoding operations.
An additional object of the present invention is to provide a coating on a ribbon having ingredients in the coating which are responsive to heat for transferring a portion of the coating to paper or like record media.
A further object of the present invention is to provide a coating on a ribbon substrate, which coating includes a pigment material and a wax emulsion dispersed in a binder mix and which is responsive to heat for transferring the coating in precise printing manner to paper or like record media.
Still another object of the present invention is to provide a thermally-activated coating on a ribbon that is transferred from the ribbon onto the paper or document in an imaging operation in printing manner at precise positions and during the time when the thermal elements of the printer are actuated to produce a well-defined and precise or sharp image.
Still an additional object of the present invention is to provide a thermal transfer layer consisting essentially of a wax emulsion to prevent smearing or scratching of printed images or other marks.
Still a further object of the present invention is to provide a process which includes the preparation of a coating on media for use in a sorting operation.
Still another object of the present invention is to provide a heat sensitive, thermal transfer ribbon created by use of a predominately water-based coating and the transferred images from the coating resist smearing, smudging or scratching of the transferred images or marks.
Still an additional object of the present invention is to provide a thermal transfer ribbon by combining thermally active materials with thermochromic dyes or pigments which upon heating create various or different color images.
Still another object of the present invention is to provide a coating or layer on a substrate to form a thermal transfer ribbon and which is capable of forming a color upon the application of heat by reason of specific ingredients in the coating and also is capable of transferring of color images onto a receiving substrate.
Still a further object of the present invention is to provide a thermal transfer ribbon that includes a coating which is environmentally acceptable by reason of the use of water-based ingredients.
Additional advantages and features of the present invention will become apparent and fully understood from a reading of the following description taken together with the annexed drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 illustrates a receiving document and a thermal element operating with a ribbon base or substrate having a layer or coating incorporating the ingredients as disclosed in the present invention; and
FIG. 2 shows the receiving document with a portion of the coating transferred in the form of a digit, symbol or other mark onto the receiving document.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The transfer ribbon 20, as illustrated in FIGS. 1 and 2, comprises a base or substrate 22 of thin, smooth, tissue-type paper or polyester-type plastic or like material having a coating or layer 24 on the substrate. The coating 24 contains thermally active material 26 in the form of particles thereof combined with pigment or dye particles 30. The coating 24 may be either magnetic, nonmagnetic or fluorescent in nature and comprise certain essential ingredients for use in imaging or encoding operations to enable machine reading, or human reading, or reflectance reading, of characters or other marks. Each character or mark that is imaged on a receiving paper document 28 or like record media produces a unique pattern or image 34 that is recognized and read by the reader. In the case of thermal transfer ribbons relying solely on the nonmagnetic thermal printing concept, the pigment or particles 30 include coloring materials such as pigments or dyes. In the case of ribbons relying on the magnetic thermal printing concept, the pigment or particles 30 include magnetic oxides or like sensible materials.
As alluded to above, it is noted that the use of a thermal printer having a print head element, as 32, substantially reduces noise levels in printing operation and provides reliability in imaging or encoding of paper or like documents 28. The thermal transfer ribbon 20 provides the advantages of thermal printing while encoding or imaging the document 28 with a magnetic or with a nonmagnetic signal inducible ink. When the heating elements 32 of a thermal print head are actuated, the imaging or encoding operation requires that the pigment 30 and other particles of material 26 in the coating 24 on the coated ribbon 20 be transferred from the ribbon to the document 28 in manner and form to produce precisely defined characters 34 on the document for recognition by the reader. In the case of nonmagnetic thermal printing, the imaging or encoding materials 26 and 30 are transferred to the document 28 to produce precisely defined characters 34 for recognition and for machine, human, or reflectance reading thereof.
The coating or layer 24 is provided directly on the substrate 22 and the coating exhibits the following characteristics, namely, the coating must be resistant to normal operational parameters and must not inhibit transfer of the thermal-sensitive materials 26 and 30 at a normal print head energy, and the coating 24 must allow a bond of the thermal-sensitive materials in the coating onto the paper 28 upon transfer of such materials.
A preferred formulation for the coating 24 includes the ingredients in appropriate amounts as set forth in Example I.
EXAMPLE I
______________________________________Component & ComponentCommercial Solids Percent Batch Batch ExperimentalGrade (Fraction) Dry Dry Wet Range %______________________________________Carbon Black 1.0 18.0 22.5 22.5 8-40(RP-450)Polyox 0.1 3.0 3.8 37.5 2-8(N-10)Casein 0.1 4.0 5.0 50.0 2-8(BL-380)HDPE Emulsion 0.4 15.0 18.8 46.9 1-40(ME-46940)Carnauba Emul 0.25 60.0 75.0 300.0 15-75(ML-16025)Subtotal 100.0 125.1 456.9N-Propanol or 37.5 5-15IsoPropanol (10%)De-Ionized Water (90%) 5.6 BalanceTotal 100.0 125.1 500.0Wet Batch: 500 Design Solids: 25.0% 15-35______________________________________
All quantities in the above example are in grams. The figures for the component solids are the non-volatiles or ratios of solids to the total. It is to be noted that the percentage of solids for the 500 gram batch of ingredients in Example I is about 25%.
The coating or layer 24 is applied to the substrate 22 by means of conventional coating techniques such as a Meyer rod or like wire-wound doctor blade set up on a typical coating machine to provide a coating weight of 5.0 to 12.0 milligrams per 4 square inches when using 18 to 22 gauge polyester film.
In the above example, a 10% solution of each of Polyox resin and casein are prepared separately using the deionized water. The Polyox resin and the casein are the two key ingredients in the coating or formulation of Example I. The Polyox resin combined with the high density polyethylene provide a very flexible coating structure and the casein creates a good adhesive bond to the polyester film. The results obtained with the Polyox resin, the casein and the high density polyethylene achieved the desired flexibility and adhesive qualities in view of the fact that it had been found previously that such results were difficult to obtain on plastic substrates with water base coatings when using emulsions of brittle waxes such as Carnauba. The Carnauba emulsion is used to accomplish transfer of the coating material by thermal energy when the coated film is operating in a thermal transfer printer. The high density polyethylene along with the casein improves the smear resistance of the thermally transferred characters or printing such as a bar code on a coated receiver sheet. The carbon black is added to the formulation as a pigment or black colorent for recognition by a bar code reader. A variety of colors are possible when using different pigments.
As alluded to above, the preferred formulation set forth in Example I provides a printed image or character that exhibits good sharpness, contrast and smear resistance on coated receiver stocks. Because of the high smear resistance characteristic of the coating of Example I, transfer of the ribbon material onto uncoated receiver stock is not as good as coated stock.
Another formulation for the coating 24 includes the ingredients and quantities set out in Example II. For applications where smear resistance is of lesser importance but where good print quality is required on both coated stock and uncoated stock, the casein and the high density polyethylene are removed from the formulation of Example I and are replaced with a larger percentage of the carnauba emulsion along with glycerine, as set forth in Example II. The glycerine maintains the flexibility of the coating.
EXAMPLE II
______________________________________Component & ComponentCommercial Solids Percent Batch Batch ExperimentalGrade (Fraction) Dry Dry Wet Range %______________________________________Carbon Black 1.0 18.0 22.5 22.5 12-40(RP-450)Polyox 0.1 3.0 3.8 37.5 2-8(N-10)Glycerine 1.0 4.0 5.0 5.0 2-8(Star)Carnauba Emul 0.25 75.0 93.7 375.0 15-75(ML-16025)Subtotal 100.0 125.0 440.0N-Propanol or 37.5 5-15IsoPropanol (10%)De-Ionized Water (90%) 22.5 BalanceTotal 100.0 125.0 500.0Wet Batch: 500 Design Solids: 25.0% 15-35______________________________________
It was found that while the presence of glycerine in the formulation of Example II provided flexibility and good transfer of the coating material onto both coated and uncoated receiver stocks, the coating on the ribbon and the transferred print are "softer" and thus not as resistant to smear. In almost all cases, there is a very good but negative correlation between print quality and smear resistance.
A further formulation for the coating 24 includes the ingredients and quantities as set forth in Example III.
EXAMPLE III
______________________________________Component & ComponentCommercial Solids Percent Batch Batch ExperimentalGrade (Fraction) Dry Dry Wet Range %______________________________________Acrylic Black 0.4 10.0 15.0 37.5 6-30(KS-1720)Carnauba Emul 0.25 45.0 67.5 270.0 30-75(ML-16025)Paraffin Emul 0.37 45.0 67.5 182.4 30-75(ML-74332)Subtotal 100.0 150.0 600.0N-Propanol or 10.0 1-10IsoPropanol (2.2%)De-Ionized Water (97.8%) 100.0 BalanceTotal 100.0 125.0 600.0Wet Batch: 600 Design Solids: 25.0% 15-35______________________________________
The formulation of Example III is for use in low energy printers which print at higher speeds in the range of 6 to 10 inches per second and which require a higher sensitivity transfer media. The higher speed printing operation is accomplished by reducing the amount of adhesive in the formulation and incorporating waxes having lower melting points. In Example III, the formulation includes a combination of Carnauba and Paraffin wax emulsions along with an acrylic carbon black dispersion. The amount of alcohol was reduced to a lower level to provide a more environmentally acceptable coating for the printing system.
An additional formulation for the coating 24 includes the ingredients and quantities as set out in Example IV.
EXAMPLE IV
______________________________________Component & ComponentCommercial Solids Percent Batch Batch ExperimentalGrade (Fraction) Dry Dry Wet Range %______________________________________Carbon Black 1.0 18.0 18.0 18.0 12-40(RP-450)Polyox 0.1 3.0 3.0 30.0 2-8(N-10)Turkey 0.5 4.0 4.0 8.0 2-8Red Oil(SulphonatedCastor Oil)HDPE 0.4 15.0 15.0 37.5 1-40(ME-46940)#1 Carnauba 0.25 35.0 35.0 140.0 5-75(ML-160)Candelilla 0.25 25.0 25.0 100.0 15-75(EE-30825)Subtotal 100.0 100.0 333.5N-Propanol or 15.0 5-15IsoPropanol (10%)De-Ionized Water (90%) 1.5 BalanceTotal 100.0 100.0 400.0Wet Batch: 400 Design Solids: 25% 15-35______________________________________
Still another formulation for the coating 24 includes the ingredients and quantities as set out in Example V.
EXAMPLE V
______________________________________Component & ComponentCommercial Solids Percent Batch Batch ExperimentalGrade (Fraction) Dry Dry Wet Range %______________________________________Carbon Black 1.0 17.8 19.2 19.2 12-40(RP-450)Surfactant 1.0 0.2 0.2 0.2 .1-1(Surfynol 104)Polyox 1.0 3.0 3.2 3.2 2-8(N-10)Gum Arabic 0.2 4.0 4.3 21.6 2-8(Flaked)HDPE 0.4 15.0 16.2 40.5 1-40(ME-46940)#1 Filtered 0.25 60.0 64.8 259.2 15-75Carnauba(ML-164)Subtotal 100.0 107.9 343.9N-Propanol or 29.2 5-40IsoPropanol (10%)Deionized Water (90%) 26.9 BalanceTotal 100.0 107.9 400.0Wet Batch: 400 Design Solids: 27% 15-35______________________________________
Still a further formulation for the coating 24 includes the ingredients and quantities as set out in Example VI.
EXAMPLE VI
______________________________________Component & ComponentCommercial Solids Percent Batch Batch ExperimentalGrade (Fraction) Dry Dry Wet Range %______________________________________Carbon Black 1.0 29.9 32.9 32.9 12-40(RP-450)#3 Carnauba 0.25 55.0 60.5 242.0 15-75(ML-156)HDPE 0.4 12.0 13.2 33.0 1-40(ME-46940)Polyox 0.1 2.0 2.2 22.0 2-8(N-10)Blue Dye 0.4 1.0 1.1 2.8 1-5(HS-1520)Wetting 0.1 0.1 0.1 1.1 .1-1Surfactant(Surfynol 104)Subtotal 100.0 110.0 333.8N-Propanol or 18.5 5-15IsoPropanol (10%)Deionized Water (90%) 147.7 BalanceTotal 100.0 110.0 500.0Wet Batch: 500 Design Solids: 22% 15-35______________________________________
Still an additional formulation for the coating 24 includes the ingredients and quantities as set out in Example VII.
EXAMPLE VII
______________________________________Component & ComponentCommercial Solids Percent Batch Batch ExperimentalGrade (Fraction) Dry Dry Wet Range %______________________________________Carbon Black 1.0 10.0 12.5 12.5 10-30(RP-450)HDPE 0.4 55.0 68.6 171.9 10-60(ME-46940)Candelilla 0.25 15.0 18.8 75.0 15-75(EE-30825)Pigmented 0.4 15.0 18.8 46.9 10-20Latex(EC-9724)Defoamer 1.0 5.0 6.3 6.3 1-5Surfactant(Surfynol GA)Subtotal 100.0 125.0 312.6N-Propanol or 37.5 5-15IsoPropanol (10%)Deionized Water (90%) 149.9 BalanceTotal 100.0 125.0 500.0Wet Batch: 500 Design Solids: 25% 15-35______________________________________
Still another formulation for the coating 24 includes the ingredients and quantities as set out in Example VIII.
EXAMPLE VIII
______________________________________Component & ComponentCommercial Solids Percent Batch Batch ExperimentalGrade (Fraction) Dry Dry Wet Range %______________________________________Carbon Black 1.0 19.9 24.8 24.8 12-40(RP-450)#3 Carnauba 0.25 48.0 60.0 240.0 15-75(ML-156)HDPE 0.4 25.0 31.3 78.1 1-40(ME-46940)Candelilla 0.25 2.0 2.5 10.0 1-10(EE-30825)Polyester Resin 0.65 5.0 6.3 9.6 1-10(HR-100)Wetting 0.1 0.1 0.1 1.3 .1-1Surfactant(Surfynol 104)Subtotal 100.0 125.0 363.8N-Propanol or 17.6 5-15IsoPropanol (10%)Deionized Water (90%) 118.5 BalanceTotal 100.0 125.0 500.0Wet Batch: 500 Design Solids: 25% 15-35______________________________________
Still a further formulation for the coating 24 includes the ingredients and quantities as set out in Example IX.
EXAMPLE IX
______________________________________Component & ComponentCommercial Solids Percent Batch Batch ExperimentalGrade (Fraction) Dry Dry Wet Range %______________________________________Carbon Black 1.0 17.9 22.4 22.4 12-40(RP-450)Polyox (N-10) 0.1 3.0 3.8 37.5 2-8HDPE (ME-46940) 0.4 15.0 18.8 46.9 1-40#3 Carnauba 0.25 60.0 75.0 300.0 15-75(ML-156)Poly-Ketone Resin 0.5 4.0 5.0 10.0 2-8(K-1717)Wetting Surfactant 0.1 0.1 0.1 1.3 .1-1(Surfynol 104)Subtotal 100.0 125.1 418.1N-Propanol or 31.4 5-15IsoPropanol (10%)Deionized Water 50.5 Balance(90%)Total 100.0 125.1 500.0Wet Batch: 500 Design Solids: 25% 15-35______________________________________
The substrate or base 22, which may be 30-40 gauge capacitor tissue, as manufactured by Glatz, or 18-21 gauge polyester film, as manufactured by duPont under the trademark Mylar, should have a high tensile strength to provide for ease in handling and coating of the substrate. Additionally, the substrate 22 should have properties of minimum thickness and low heat resistance to prolong the life of the heating elements 32 of the thermal print head by reason of reduced print head actuating energies.
The availability of the various ingredients used in the above examples of the present invention is provided by the following list of companies.
______________________________________Ingredient Supplier______________________________________Carbon Black Columbian CarbonAcrylic Black HeubachPolyethylene Oxide Resin Union CarbideCasein American CaseinHigh Density Polyethylene Michelman Inc.Carnauba wax Michelman Inc.Glycerine Proctor & GambleParaffin wax BolerTurkey Red Oil Welch, Holme & ClarkCandelilla Michelman Inc.Gum Arabic Gumix Int. Inc.Blue Dye Hilton-DavisPigmented Latex Environmental InkPolyester Resin LawterPoly-Ketone Resin LawterN-Propanol or Ashland ChemicalIsoPropanol______________________________________
Carbon Black is a pigment or colorent that provides a black print or image that is recognized by a bar code reader. Poly(ethylene oxide) resin is a nonionic ethylene oxide homopolymer that is soluble in water and in alcohol and also in a combination thereof. The Polyox resin is truly thermoplastic and completely soluble in water up to its boiling point. Poly(ethylene oxide) resin is developed by a polymerization process utilizing a chain of ethylene oxide molecules. The Polyox resin is a high polymer with the following common structure (O--CH 2 CH 2 ) n . The degree of polymerization n varies from about 2,000 to 100,000. Several grades of the poly(ethylene oxide) resin are available ranging in molecular weights from 100,000 to 5,000,000. The Polyox material assists in transfer of the images and reduces any tendency towards brittleness. Casein is a powder that provides better hardening characteristics and resistance to smear. HDPE is a high density polyethylene emulsion that provides good smear resistance. Glycerine is a plasticizer-type material that stays moist and prevents the coating or printed images from becoming brittle. It was found during the experiments that the use of glycerine loses some smear resistance but increases flexibility and transfer characteristics.
The scope of the present invention includes the use of different colors for certain applications where non-black pigments can be substituted in the coating for the ribbon. By way of example, a variety of acrylic color dispersions are available from Heubach in colors which cover the entire color spectrum.
It is also found that non-black colorents, such as Hoover 9964 red iron oxide or EH-50814 Magenta Latex can be substituted in the ribbon coatings to provide red or magenta color ribbons. In order to improve the scanning characteristics of red color thermal transfer ribbons for use with laser or infra red scanners, small amounts of infra red absorbing pigments of extremely fine particle size can be added to the coating. Specific pigments which are suitable for this purpose are Magnet Black S-0045 available from BASF, Bone Black #6 from Hoover, and Gilsonite Brilliant Black from Ziegler.
The above three specific pigments are dull gray in color but their very fine spherical particle size creates substantially transparent coatings in a range up to about 15 percent loading when using one or another of such pigments. It is also found that these pigments do not influence the color of the coating substantially when added to tones of darker colors such as Magenta RS1115 or Blue HS1520 available from Heubach. Latex dispersed pigments such as Magenta EP-50184 or Blue EP-2379 available from Environmental Ink can also be substituted as non-black pigments in the coating of the ribbon.
And, still an additional formulation for the coating 24 is set out in Example X.
EXAMPLE X
______________________________________Component & ComponentCommercial Solids Percent Batch Batch ExperimentalGrade (Fraction) Dry Dry Wet Range %______________________________________Magenta 0.4 20.0 25.0 62.5 15-30(EH-50814)HDPE (ME-46940) 0.4 20.0 25.0 62.5 10-40BASF Oxide 1.0 15.0 18.8 18.8 12-18(S-0045)#3 Carnauba 0.25 35.0 43.8 175.0 25-60(ML-156)PolyKetone 0. 33 10.0 12.5 37.9 8-15(K-1717)Subtotal 100.0 125.0 356.6N-Propanol (10%) 12.1 5-15Deionized Water 131.3 Balance(90%)Total 100.0 125.0 500.0Wet Batch: 500 Grams Design Solids: 25% 15-35______________________________________
The Polyketone K-1717 is prepared as a 33% solution in solvent. The Magenta EH-50814 is supplied by Environmental Ink.
It is to be noted that in the development of the water base emulsion technology, hundreds of different coatings have been created. These coatings cover a wide range of compounds and ingredients, however the following summary provides additional scope of the present invention.
In the case of low energy printers, as known in the industry, block polymers of Styrene-Butadiene, such as Kraton 1107 and 1101 made by Stevens, or Polyacrylic rubber such as Rhoplex N-619 made by Rohm and Haas, or Polyurethane emulsions made by MACE Adhesive and Coating, Inc. can be substituted as elastomers to provide the flexibility and adhesion and thereby improve the printing performance in such low energy printers.
Ethylene Oxide polymer such as Polyox N-10 or N-80 made by Union Carbide, Casein BL-380 made by American Casein, Acrylic/Vinyl Acetate copolymers supplied by Rohm and Haas, Polyvinyl Alcohol supplied by Air Reduction, and water soluble cellulosic polymers such as Nitrosol or Methocel provided by Hercules and Carboxy Methyl Cellulose supplied by Union Carbide, all for the purposes of providing toughness and cohesion of the coating, have been evaluated and documented.
A wide variety of resin emulsions of Polyacrylate Esters such as MMA, BMA and EMA supplied by Rohm and Haas, Polyester, Polyamide, Polyethylene, Polypropylene and Silicone emulsions supplied by Michelman, and Phenolic resin dispersions supplied by BASF and Schenectady have been evaluated with the results that such emulsions show an improvement in smear and in scratch resistance.
It is also to be noted that the wax emulsions are the key transfer agents, and include #1 Carnauba, #3 Carnauba, Carnauba-Paraffin, Carnauba-Polyethylene, Rice Bran, Candellila, Ethylene Acrylic Acid, Hystrene 9022, Stearic Acid, Palm Wax and Beeswax supplied by Michelman.
Small amounts of defoamers such as Nopco NDW and Surfynol 104, supplied Nopco Chemical and Airco Chemical, respectively, are incorporated in the dispersion or grinding process to control foam and improve "wetting" of the pigments or dyes.
Additional advantages of the present invention are that disposal of excess materials is not a problem, that excess materials can be saved for reuse, and that the water-based process enables safety at room temperature processing.
It is thus seen that herein shown and described is a thermal transfer ribbon for use in thermal printing operations that includes a water-based coating acceptable for environmental conditions. The single coating or layer includes thermally active or transfer material for imaging onto a receiving sheet. The present invention enables the accomplishment of the objects and advantages mentioned above, and while a preferred embodiment has been disclosed herein, variations thereof may occur to those skilled in the art. It is contemplated that all such variations and any modifications not departing from the spirit and scope of the invention hereof are to be construed in accordance with the following claims.
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A thermal transfer ribbon has a substrate and a coating which contains thermally active ingredients for transferring images onto a receiving medium upon the application of heat to said ribbon. The ingredients are predominately water based and are environmentally acceptable in the industry. The various ingredients provide a flexible coating structure and a good adhesive bond along with improved resistance to smear and smudging of the transferred images. The thermal transfer formulation comprises carnauba wax and paraffin wax emulsified in a mixture of 1-10% volatile solvent and about 90-99% water.
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This application is a continuation of application Ser. No. 095,172, filed July 31, 1987, now abandoned.
BACKGROUND OF THE INVENTION
This invention relates to printing machines and particularly to a numbering machine of the kind used for printing repeatedly incremented numerical or alpha numerical codes on a train of documents.
One intended use of the invention is in a multistage machine, usually called web machine, employed for the printing of documents, e.g., bank notes. In such a machine a paper web, on which a train of documents is printed, is continuously transported at comparatively high speed through a multiplicity of printing and treatment stages, including a numbering station. Such a numbering station usually comprises a numbering cylinder which carries at least one set of numbering barrels, the barrels in each set being at spaced locations around its periphery. The printing cylinder co-operates with an impression roll to form a printing nip. Usually the numbering station is downstream from various printing stages which print, in one or more columns, a multiplicity of documents.
However the invention is also applicable where the documents are presented separately but in rapid succession.
It is usual for the numbering barrels on each printing cylinder to be incremented by a suitable modulus automatically between successive discrete angular positions so as to produce (though not necessarily from a single printing cylinder) a continuous series of numbers on the pre-printed documents when the machine is running normally. In such a machine as has been described, it would be desirable to cease overprinting by means of the numbering cylinder if a "spoil" document were detected. It will be understood that where overprinting is to be performed on documents which are printed as part of a continuous web, and the web contains random "spoil" documents (otherwise called misprints) it is desirable to inhibit the printing of, for example, a number in the series on the "spoil" document so that, after the documents have been individually separated from the web and the spoil documents have been removed, the remaining "good" documents bear respective numbers or alpha numeric codes in an unbroken sequence.
Numbering machines of the kind with which the present invention is concerned can be adjusted so that the incrementing of the numbering barrels can be inhibited for long runs but hitherto have not been adapted for the selective inhibition of incrementing such that randomly occurring "spoil" documents are not overprinted, i.e., they are omitted from the numbering sequence.
It is known from European Patent Application No. 85303863.6 (published Dec. 27, 1985 as EP-A2-0165734) to provide a spoil detector which can provide, in real time, scanning of documents on a continuously moving web and a control signal which denotes a "spoil" document. The present invention may be used in conjunction with such a detector.
SUMMARY OF THE INVENTION
The present invention is based on an improvement to a machine for printing on a train of sheets or documents and having a transport mechanism for driving the documents in succession through at least one printing station, the machine comprising a printing cylinder having spaced apart around its periphery one or more salient printing devices (such as numbering barrels) and drive means for rotating the printing cylinder at an operating speed corresponding to that of the sheets or documents whereby printing is effected on a document as the or each successive printing device forms a nip with an impression cylinder. An ordinary numbering machine of this kind will automatically increment the code provided by a respective numbering barrel in the interval between successive nips.
The basis of the present invention is the selective change of the printing cylinder from its normal operating speed and restoration of the printing cylinder back to its normal operating speed. In particular, the noted change is preferably a deceleration so that before the next printing nip is formed, the train of sheets or documents overtakes the printed cylinder by at least the distance between successive angular positions in which a nip can be formed.
By means of the present invention, when all the (pre-printed) documents are to be overprinted, the printing cylinder will run at the operational speed corresponding to the speed of the documents. If a document passing through the printing nip is not to be overprinted, the printing cylinder decelerates to a slow speed or to rest so that it allows at least one document to pass through the region of the printing nip without being overprinted. On resumption of printing, the printing cylinder is accelerated to a speed corresponding to the speed of the documents and into phase lock with the documents in the correct printing position before the next nip is formed with the impression roll.
In the application of the invention to the control of a printing cylinder with a numbering barrel or barrels, the invention facilitates the maintenance of a complete series of codes on the documents which are actually overprinted, since the deceleration and acceleration of the printing cylinder can occur within the interval between successive nip-forming positions.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a known form of numbering machine;
FIGS. 2 and 3 illustrate a detail of the numbering machine;
FIG. 4 illustrates schematically a control system for use with the numbering machine; and
FIG. 5 illustrates part of the control system in greater detail.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The printing station shown in the drawing includes a printing cylinder 1 of the kind having at least one numbering barrel and preferably a plurality of (in this example five) numbering barrels 2 spaced apart around its periphery. The printing cylinder is adjacent an impression roll 3 of which the height relative to the printing cylinder is adjustable by means of an eccentric 4 operable by a piston and cylinder assembly 5. The eccentric carries an abutment member 6 with end faces 7 and 8 engageable with adjustable end stops 9 and 10.
Each numbering barrel 2 can form a nip with the impression roll. A web 11, on which documents such as bank notes are printed at discrete intervals, is transported at a continuous, comparatively high speed (typically corresponding to an operating speed of 240 rpm for the printing cylinder).
Above the printing cylinder is an ink roll 12 engaging, in this embodiment, two forme rolls 13 and 14 positioned for successive engagement by the printing barrels 2. The forme rolls are each movable towards and away from the printing cylinder.
Drive for the impression roll and the rolls 12 to 14 may be provided by a suitable motor (not shown).
The numbering machine as so far described is of a well-known type which will be familiar to those skilled in the art. The machine may form part of a finishing machine by means of which bank notes or other documents which are pre-printed on the web 11 are overprinted, cut to size and sorted into bundles. Although the construction of a numbering machine is well-known, and the particular construction is not part of the invention, there follows for the sake of completeness a brief description of the operation of a numbering box or barrel with reference to FIGS. 2 and 3.
FIGS. 2 and 3 illustrates a shaft 20 on which are mounted numbering barrels 2 of which only one is shown in FIG. 2. The shaft 20 carries a mounting ring 21 having peripherally spaced grooves into each of which the frame 22 of a numbering barrel is secured, the foot 23 (FIG. 3) of the frame engaging a lip 24 at one side and a wedge 25, secured by a bolt to the ring 21, at the other. The radial position of the frame may be determined by a locating stop pin 26 disposed in a bore in the ring 21.
The frame 22 carries a respective numbering barrel 2 which is incremented by a pawl (not shown) actuated by a cam follower, comprising a crank 27 and a roller 28. The roller 28 engages a groove 29 in a cam track 30 disposed adjacent the path of the numbering barrel; the crank 27 is rotated through a suitable angle (such as 45°) to operate the pawl.
It is known practice to move the cam track to prevent normal operation of the roller but it is not practicable to inhibit the action of the numbering barrel in this way except for long periods.
Although the foregoing description is based on a machine in which overprinting is to be performed on a continuous web, the same general considerations apply to overprinting on each of a succession of sheets fed through the numbering machine.
FIG. 4 illustrates in schematic form the main features of one embodiment of a control system for the numbering machine. The impression roll 3, which is driven at a peripheral speed corresponding to that of the web 11, has an encoder 40 which provides (in a manner known in itself) a set of parallel digital signals denoting the instantaneous position and speed of the impression roll and thereby the position and speed of the web. The encoder could be located elsewhere and could be driven directly by the web.
The numbering shaft 20 drives a tachometer 41 and a shaft encoder 42. A control circuit 43 (shown in more detail in FIG. 5) compares the signals from the encoders and controls a servo amplifier 44 in accordance with any phase error between the impression roll and the numbering shaft, so that the motor 45, which is driven by the servo amplifier, drives the numbering shaft in phase synchronism with the impression roll (and thereby with the web). In normal operation, that is to say in the absence of any detection of spoiled documents, the numbering cylinder overprints each successive document on the web. Typically the printing of the numbering cylinder will be to an accuracy better than 0.2 mm.
At some suitable position upstream of the numbering machine a spoil detector 46, which may be of the kind previously mentioned, scans the documents to detect any spoil, according to any suitable criteria. The spoil detector provides to the control circuit 43 a signal which initiates a command sequence by means of which the numbering shaft is, after a suitable delay which may be necessary to allow the spoiled document to reach the numbering machine, decelerated to allow the spoiled document to pass by the respective numbering barrel. The servo mechanism preferably decelerates the printing cylinder 1 so that it comes to rest in a parked position between two adjacent phase positions in which a nip is formed with the impression roll. For a printing cylinder with five equally spaced numbering barrels, such nip-forming positions occur at 72° intervals; the parked position is at some convenient point within such an interval. If only one document, or row of documents, is not to be overprinted, the printing cylinder may be immediately restarted. When overprinting is to recommence, the timing and acceleration are such that the printing cylinder is accelerated to synchronous speed before the next printing barrel forms a printing nip with the impression cylinder.
The restart of the printing cylinder may of course be inhibited for such time as may be desired; but is always retimed such that synchronism of the printing cylinder is achieved by the time the next nip-forming position is reached. In practice, prior to deceleration there may be about 7 to 8° synchronous movement after a nip-forming position after which deceleration commences and a similar amount of movement before the respective nip-forming position immediately after acceleration is completed. Typically the positional accuracy for the first printing after acceleration is better than 0.4mm, subsequent printings having the accuracy aforementioned.
FIG. 5 illustrates in simplified manner the operation of the servo control circuit 43. This is organized on the ordinary lines of a digitally controlled position servo which provides for traversal at a controlled rate and for stopping a controlled member on command. Such techniques are well-known in for example the art of digital recording on tape or disc.
The servo circuit comprises four main sections, namely a central processing section 50, a digital to analogue converter 51, a servo section 52 and a counter section 53. The central processing section controls the flow of data and/or clock signals along a data bus 54. The counter section includes an interface 55 which receives spoil signals and clock signals on lines 56, a reference counter 57 receiving the output of the impression roll encoder 40 on lines 58 and a slave counter 59 receiving the output of the numbering shaft encoder 42 on lines 60. The central processing section 50, which receives basic serial commands (such as start and stop commands) on line 61, will during normal operation effect sampling and comparison of the contents of the counters 57 and 59 to compute a digital error signal which is directed to the digital to analogue converter 51. The error is converted therein to an analogue signal which is processed by the servo 52 to provide a command signal on line 62 for the servo amplifier 44 (FIG. 4).
On detection of a spoil signal the central processing section interrupts the normal servo action and provides a command signal such as to decelerate the numbering shaft, preferably to zero velocity. This may be achieved by providing to the servo circuit by way of the converter 51 either a signal denoting zero velocity or a succession of signals defining a braking profile. In either case the resultant output of the converter 51 may be compared with the velocity feedback signal from the tachometer to bring the numbering shaft to rest under servo control.
The central processing section will ascertain that the numbering shaft is to be restarted by strobing the interface section to detect the absence of a spoil signal and will permit the normal servo action, under the control of counters 57 and 59 to recommence. The gain of the servo circuit should be sufficient to cause the acceleration of the numbering shaft to normal speed before the next printing nip is formed, but in practice this requirement is easily fulfilled.
The servo circuit comprises an amplifying stage 63 followed by a shaping stage 64 for the signal from the digital to analogue converter 51. This signal is combined when necessary with a velocity feedback signal obtained on line 65 from the tachometer and developed by an input stage 66 followed by an amplifying stage 67. The output of the summing stage 68 is fed to a shaper 69, an amplifying stage 70 and an output stage 71 to provide on line 62 the command signal to the servo amplifier 44. Switching of the gains of the servo circuit for the different operational modes is effected by control signals from the processing section 50.
The invention may be used for providing any selected change in the positional relationship between the printing cylinder and the train of sheets or documents; it is possible to provide an increase in the speed of the printing cylinder and subsequently a decrease to the normal operating speed.
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A printing machine which has a printing cylinder (1) having automatically incremented numbering barrels (2) includes drive means (40-45) which normally maintain the printing cylinder in speed and phase synchronization with a train of documents on a web (11). The drive means is operable to decelerate the printing cylinder and then to cause the printing cylinder to regain its normal operating speed so that the web overtakes the printing by a selected distance before the next printing nip is formed.
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BACKGROUND OF THE INVENTION
This invention relates to woven papermakers' fabrics and especially to forming fabrics, including those known as fourdrinier wires.
In the conventional fourdrinier papermaking process, a water slurry or suspension of cellulosic fibers, known as the paper "stock", is fed onto the top of the upper run of a traveling endless belt or fabric of woven wire and/or synthetic material. The belt provides a papermaking surface and operates as a filter to separate the cellulosic fibers from the aqueous medium to form a wet paper web. In forming the paper web, the forming belt serves as a filter element to separate the aqueous medium from the cellulosic fibers by providing for the drainage of the aqueous medium through its mesh openings, also known as drainage holes. In the conventional fourdrinier machine, the forming fabric also serves as a drive belt. Accordingly, the machine direction yarns are subjected to considerable tensile stress and, for this reason, are sometimes referred to as the load bearing yarns. Additionally, the cross machine direction yarns on the bottom surface of the forming fabric are subjected to the abrasive forces of the paper machine elements and, for this reason, are often times referred to as the wear resisting yarns.
Such papermakers' fabrics are manufactured in two basic ways to form an endless belt. First, they can be flat woven by a flat weaving process with their ends joined by any one of a number of well known methods to form the endless belt. Alternatively, they can be woven directly in the form of a continuous belt by means of an endless weaving process. In a flat woven papermakers' fabric, the warp yarns extend in the machine direction and the filling yarns extend in the cross machine direction. In a papermakers' fabric having been woven in an endless fashion, the warp yarns extend in the cross machine direction and the filling yams extend in the machine direction. As used herein, the terms "machine direction" and "cross machine direction" refer respectively to a direction equivalent to the direction of travel of the papermakers' fabric on the papermaking machine and a direction transverse to this direction of travel. Both methods are well known in the art and the term "endless belt" as used herein refers to belts made by either method.
Effective sheet support and minimal wire marking are important goals in papermaking, especially for the belt in the section of the papermaking machine where the wet web is formed. The fibers in the slurry to form the paper are generally of relatively short length. Accordingly, in order to ensure good paper quality, the side of the papermakers' fabric which contacts the paper stock should provide high support for the stock, preferably in the cross machine direction because paper fibers delivered from the headbox to the forming fabric are generally aligned in the machine direction more so than they are aligned in the cross machine direction. Retaining these paper fibers on the top of the forming fabric during the drainage process is more effectively accomplished by providing a permeable structure with a paper contacting surface grid configuration that increases the probability that paper fibers will be supported. Thus the grid spans in both directions should be shorter than the paper fibers so that a high percentage of bridging occurs.
However, if the grid configuration of papermakers' fabric were designed with only fiber retention in mind, such forming fabrics would probably be delicate and lack stability in the machine direction and cross machine direction, leading to a short service life. As noted above, abrasive wear caused by contact with the papermaking machine equipment is a real problem. The side of the papermakers' fabric which contacts the paper machine equipment must be tough and durable. These qualities, however, most often are not compatible with the good drainage and fiber supporting characteristics desired for the sheet side of the papermakers' fabric.
Hence, the ideal papermaking fabric must be fine enough to support and retain a high percentage of the deposited paper fibers, durable enough to withstand wear and give adequate life, strong enough to resist tensile forces to minimize stretching, and open enough to provide drainage and to simplify cleaning. Meeting these multiple criteria generally requires that two layers of fabric be woven at once by utilizing threads of different size and/or count per inch for the sheet making portion and the wear/stretch resisting portion respectively.
In fabrics thus created from two distinct fabrics, the final fabric would have the desirable papermaking qualities on the surface that faces the paper web and the desirable wear resistance properties on the machine contacting surface. In practice, such papermakers' fabrics are produced from two separate fabrics, one having the qualities desired for the paper contacting side and the other with the qualities desired on the machine contacting side and then the two fabrics are stitched together by additional stitching yarns as a single papermakers' fabric. This type fabric is commonly called a triple-layer or TRI-X fabric.
The main problem with so-called triple-layer or TRI-X fabrics wherein the two fabric layers are connected with additional stitching yarns is that an optimum geometry relationship between the two fabric layers is not generally achievable. In practice, the two fabric layers nest together with the bottom surface of the top fabric down in the top surface of the bottom fabric, that is the yarn systems in both directions, machine direction and cross machine direction, in both fabrics, the top fabric and the bottom fabric, are unstacked relative to each other. Therefore, although the drainage holes in the top fabric may be uniform, the individual drainage paths through the composite structure can vary due to the nesting nature of the totally unstacked structure. This unequal or non-uniform drainage path condition can be further aggravated through the addition of the independent stitching yarns required to tie both fabrics together.
Other undesirable aspects of independently stitched and totally unstacked or intimately nested so-called triple-layer forming fabrics include reduction in potential permeability and susceptibility to stitch yarn failure and subsequent ply separation. The lessened permeability can adversely affect slurry drainage, sheet knockoff capability and fabric cleaning efficiency. The stitching yarn failure can occur externally, that is on the sheet side surface or on the machine side surface, or internally, that is within or between the top fabric and the bottom fabric, depending upon the degree of burial below the respective surfaces in the one case and the amount of movement between the two fabrics in the other case. For obvious geometric reasons the stitching yarn in an independently stitched triple-layer fabric must be a relatively small diameter yarn; hence it is often hard pressed to withstand the imposed tensile and abrasive forces. Yet another drawback of independently stitched so-called triple-layer forming fabrics is increased production costs. Where the stitching yarns are inserted as picks or shutes the weaving time is at a minimum increased in direct proportion to the number of additional strands per inch required to achieve a satisfactory, from the marking standpoint and the structural standpoint, stitching pattern. In the case of a flat woven product (which essentially all triple-layer products have been to date), the subsequent cost of joining needed to make the product endless for operation on the papermaking machine is also increased.
To date no known fabric has incorporated at one time all the qualities, that is maximum fiber support, uniform drainage paths, high permeability, good stretch resistance, and long life potential desirable, for the production of superior paper. It has long been desired to devise such a product for an economical cost that falls within the criteria established in the brown paper market. Since brown paper must be produced at a relatively low cost as compared to other papers, such a fabric would be ideal, and cost effective, for all types of paper.
Accordingly, it is an object of the present invention to provide a papermakers' forming fabric suitable for, but not restricted to, the formation of brown paper.
It is another object of the present invention to provide a papermakers' forming fabric having a papermaking surface with a high fiber support for effective forming and efficient release of the paper web.
Another object of the present invention is to provide a papermakers' forming fabric having uniform drainage paths through the structure from the sheet side surface to the machine side surface.
A further object of the present invention is to provide a papermakers' forming fabric with high permeability and high stretch resistance for effective draining and efficient cleaning with trouble-free running.
Another object of the present invention is to provide such a papermakers' forming fabric while maintaining a durable wear resistant machine element contacting surface.
Still another object of the present invention is to provide a papermakers' forming fabric, the economics of which fall well within that of even brown paper parameters.
SUMMARY OF THE INVENTION
The present invention is a multi-layer papermakers' forming fabric, particularly useful for the production of brown paper. The fabric, which could be classified as a true dual-layer fabric, incorporates a top papermaking surface fabric formed of relatively fine machine direction and cross machine direction yarns and a bottom machine equipment contacting surface fabric formed of relatively coarse machine direction and cross machine direction yarns. The fabric is a self-stitched construction in which selected top fabric layer cross machine direction yarns will descend to the bottom fabric layer and wrap around certain bottom fabric layer machine direction yarns to bind the two fabric layer together. The optimum geometric structure is achieved by designing and matching the top fabric layer and the bottom fabric layer such that ideal seating conditions and ideal self-stitching conditions are realized.
The ideal self-stitching condition between the top fabric layer and the bottom fabric layer is one in which the path of the self-stitch yarn is symmetrical and the elongation of the self-stitch yarn is minimal for the particular weave pattern combination. In an optimum location for the self-stitching, the distortion of the top fabric layer sheet surface will be minimized and the burial of the self-stitch yarn relative to the bottom fabric layer machine surface will be maximized. The proper self-stitch pattern will also produce a composite fabric having the required amount of structural integrity.
In a further embodiment of the fabric of the present invention, the ideal interface symmetry between the top fabric layer and the bottom fabric layer is one where the weaves are positioned such that the machine direction floats of the one fabric are interfaced against the cross machine direction floats of the other fabric in a 90 degree cross-shaped orientation made. It is this seating arrangement that optimizes the uniform drainage paths and the permeability needed to produce a good draining and easily cleaned forming fabric.
The invention will be further described with reference to the accompanying drawing, in which like reference numbers refer to like members throughout the various views.
BRIEF DESCRIPTION OF THE DRAWING
FIGS. 1a-1c illustrate the upper papermaking surface, a machine direction section, and a cross machine direction section, respectively, of the top fabric layer of one embodiment of the fabric of the present invention.
FIGS. 2a-2d illustrate the bottom fabric layer upper interfacing surface, a machine direction section, and two cross machine direction sections, respectively, of one embodiment of the fabric of the present invention.
FIGS. 3a-3e illustrate the various seating arrangements possible for the cross machine direction yarn floats of the top fabric and bottom fabric layers for the fabric of the present invention.
FIG. 4 illustrates the relationship between the papermaking surface of the top fabric layer and the interfacing surface of the bottom fabric layer showing the ideal seating arrangement utilized in the fabric of the present invention.
FIG. 5 illustrates the relationship between the bottom surface imprint of the top fabric layer and the top surface imprint of the bottom fabric showing the 90° seating arrangement layer of the fabric of the present invention.
FIGS. 6a-6e illustrate the top fabric layer sheet making surface and the bottom fabric layer interfacing surface, two machine direction sections and two cross machine direction sections, respectively, of the preferred embodiment of the fabric of the present invention.
FIG. 7 illustrates the papermaking surface view of the top fabric layer overlaid on the interfacing surface view of the bottom fabric layer of the preferred embodiment of the fabric, as also shown in FIGS. 6a-6e.
FIG. 8a illustrates a cross machine section of the fabric of FIG. 7, taken along the line 8a--8a in FIG. 7 and FIG. 8b illustrates a cross machine section of the fabric of FIG. 7, taken along the line of 8b--8b in FIG. 7.
DETAILED DESCRIPTION OF THE INVENTION
The invention will initially be described broadly, with a more detailed description following.
The present invention is a papermakers' forming fabric particularly useful for, but not restricted to, the formation of brown paper. The fabric has a high fiber support, uniform drainage paths, high permeability, high stretch resistance, good abrasion resistance, and can be produced at a cost that makes it economical as a brown paper forming fabric.
The fabric of the present invention is a self-stitched construction including two essentially distinct fabric layers, one on top of the other. The top layer that will form the papermaking surface incorporates relatively fine yarns in both the machine direction and the cross machine direction, which, in the preferred embodiment, are woven in a 2×2 weave pattern. The bottom fabric layer that will contact the machine elements incorporates relatively coarse yarns in the machine direction and the cross machine direction, also preferably in a 2×2 weave pattern. This fabric is essentially a hybrid double-layer structure in that each layer contains its own system of machine direction yarns and cross machine direction yarns. The only discontinuity in either layer occurs when selected cross machine direction yarns from the top fabric layer dive down and engage selected machine direction yarns from the bottom fabric layer to create the composite structure by binding the two layers together. No additional binding thread is necessary. The required ideal seating condition and ideal self-stitching condition are described with reference to the drawing below.
The machine direction yarns and the cross machine direction yarns used in the present invention are preferably synthetic yarns of materials conventionally used in such fabrics, such as polyamides (Nylon), polyesters (Dacron), and acrylic fibers (Orlon, Dynel and Acrilan), or co-polymers (Saran). The machine direction yarns and the cross machine direction yarns may be in the form of monofilament, multifilament or staple yarns or plied or wrapped yarns. The specific physical properties of the selected yarns, for example, modulus, elongation, free shrink and thermal shrink can be chosen to optimize the geometry configuration of the final fabric product.
The diameter of the yarns employed in the fabric for the present invention is determined by the position in the fabric structure. The machine direction yarns and the cross machine direction yarns in the top fabric layer are approximately equal in diameter and approximately half the size of the machine direction yarns and the cross machine direction yarns in the bottom fabric layer, those yarns also being approximately equal in diameter. In a preferred embodiment, the top fabric layer incorporates yarns that are 0.16 millimeter (machine direction) by 0.18 millimeter (cross machine direction) and the bottom fabric layer incorporates yarns that are 0.34 millimeter (machine direction) by 0.36 millimeter (cross machine direction). The size of the yarns in both systems can be increased or decreased to suit the individual requirements of a particular application for the papermaking fabric.
The weave pattern used in the preferred embodiment of the fabric of the present invention is a twill weave characterized by a diagonal line on the face of the fabric. Both the top fabric layer and the bottom fabric layer are 2×2 twill, meaning that the machine direction yarns go over two cross machine direction yarns and under two cross machine direction yarns in a repeating pattern. To achieve the stated goals of the ideal seating arrangement and the ideal self-stitching arrangement of the present invention, the twills in the mating fabrics will have a reverse orientation relative to each other, that is the upper surface of the top fabric layer is a right to left twill while the upper surface of the bottom fabric layer is a left to right twill or vice versa. In combination with the above-mentioned reversed twill criteria, the top fabric layer and the bottom fabric layer must be positioned relative to each other such that the relationship between the lower surface machine direction floats of the top fabric layer interface with the upper surface cross machine direction floats of the bottom fabric layer in a maximum contact same plane, essentially 90 degree cross shaped orientation mode, which provides ideal interface symmetry.
Turning now to the drawings, FIG. 1a illustrates the upper papermaking surface of the top fabric layer, FIG. 1b is a machine direction section (taken along line 1b--1b in FIG. 1a), and FIG. 1c is a cross machine direction section (taken along line 1c--1c in FIG. 1a), respectively, of the top fabric layer of one embodiment of the present invention. As stated above, the top fabric layer 10 includes relatively fine machine direction 12 and cross machine direction 14 yarns interwoven in a 2×2 twill weave pattern. The floats of cross machine direction yarn 14 can be seen across the papermaking surface view. Consistent with the 2×2 twill weave, these floats ascend from right to left across the fabric 10, constituting a right to left twill.
FIGS. 2a illustrates the upper interfacing surface of the bottom layer fabric, while FIG. 2b illustrates machine direction section (taken along the line 2b--2b in FIG. 2a), and FIGS. 2c and 2d illustrate cross machine direction sections (taken along the lines 2c--2c and 2d--2d in FIG. 2a), respectively, of the bottom fabric layer used in one embodiment of the fabric of the present invention. Again, the bottom fabric layer 20 includes relatively coarse machine direction 22 and cross machine direction 24 yarns interwoven in a 2×2 twill pattern. The floats of cross machine direction yarn 24 can be seen across the interfacing surface view in FIG. 2a. Consistent with the 2×2 twill weave, these floats ascend from left to right across the bottom fabric layer constituting a left to right twill which is the reverse of the right to left twill in the top fabric layer 10. Within the teachings of the present invention, a top fabric layer having a left to right twill could be mated with a bottom fabric layer having a right to left twill. The points marked "S" in three views represent a typical point where the fine cross machine direction yarn from the top fabric layer could descend to bind around the coarse machine direction yarn in the bottom fabric layer 20. Examination of these views will reveal a number of other "S" type locations which would satisfy the ideal self-stitch point requirements. The number of such locations actually utilized in the ultimate composite fabric is again dependent upon the stitching frequency needs determined feasible for the product application.
FIGS. 3a-3e illustrates the possible and the ideal seating arrangements between the top fabric layer 10 and the bottom fabric layer 20 at the stacked or overlying cross machine direction yarns. In each of these views, the top fabric layer machine direction yarns 12 and the bottom fabric layer machine direction yarns 22 are unstacked, that is each bottom fabric layer machine direction yarn 22 is intermediately spaced between a pair of top fabric machine direction yarns 12. Conversely, the non-stitching cross machine direction yarns 14 of the top fabric layer and the cross machine direction yarns 24 of the bottom fabric layer are stacked. That is, the bottom fabric layer cross machine direction yarn 24 is directly under the top fabric layer cross machine direction yarn 14. This is illustrated in FIG. 3a and FIG. 3e. There are twice as many cross machine direction yarns 14 in the top fabric layer 10 as there are cross machine direction yarns 24 in the bottom fabric layer 20. As described in lines 13-16 on page 7 of this specification, only selected top fabric layer cross machine direction yarns will descend to the bottom fabric layer and wrap around certain bottom fabric layer machine direction yarns to bind the two fabric layers together. Those selected cross machine direction yarns which descend ("stitchers") alternate with cross machine direction yarns which do not descend ("non-stitchers"). FIGS. 3a-3e show positions of only a non-stitching cross machine direction yarn of the top fabric layer relative to a cross machine direction yarn of the bottom fabric layer. This distinction is further explained by comparing FIGS. 3a-3e to FIGS. 6b and 6c. Within these bounds, the top fabric layer 10 can then be positioned relative to the bottom fabric 20 in four locals, labeled Ideal, One-Left, Two-Left, Three-Left, and Ideal again respectively. It should also be noted that only in the ideal position are the top fabric layer 10 and the bottom fabric layer 20 oriented such that both lower surface machine direction floats of the top fabric layer 10 interface with the upper surface cross machine direction floats of the bottom fabric layer in the prescribed maximum contact same plane, essentially 90 degree, cross shaped orientation mode, as shown in FIG. 5 and described below.
FIG. 4 illustrates the relationship between the papermaking surface of the top fabric layer 10 and the interfacing surface of the bottom fabric layer 20 where the above-described seating arrangement has been achieved. For further familiarization of the ideal self-stitch point concept, the self-stitching points used in the composite fabric structure of one embodiment of the present invention have been marked with a "o" and labeled "S". Once again, more or less self-stitching points could be utilized, provided they meet the ideal location criteria, depending upon the overall papermaking and structural requirements of the final composite forming fabric product.
FIG. 5 illustrates the relationship between the lower surface imprint of the top fabric layer 10 and the upper surface imprint of the bottom fabric layer 20 utilized in one embodiment of the present invention. The mating of these respective imprints indicate the areas where the yarns of the two fabric layers interface. Specifically, when the ideal seating arrangement has been achieved, the lower machine direction floats 12 of the top fabric layer 10 contact the upper cross machine direction floats 24 of the bottom fabric layer 20 in a maximum contact same plane, essentially 90 degree cross shaped orientation mode, the cross shape being shown in FIG. 5; this ideal interface area is circled in FIGS. 3a and 6b. Additionally, a typical ideal self-stitching point "S" where the fine cross machine direction yarn 14 of the top fabric layer 10 can most easily dip down, specifically dip further down from its already down position, to engage the machine direction yarn 22 of the bottom fabric layer 20 at its highest most accessible point is indicated by the "S" label. Once again, both the ideal seating arrangement and the ideal self-stitching points are representative typical positions which occur frequently within a pattern repeat. In a properly designed composite fabric, all the interfacing areas should satisfy the ideal seating arrangement criteria. However, the number of ideal self-stitching points "S" actually utilized within a pattern repeat will depend upon the ultimate objectives for the product.
FIG. 6a illustrates the combined structure, specifically the relationship between the sheet making upper surface of the top fabric layer 10, and interfacing upper surface of the bottom fabric layer 20 of the preferred embodiment of the present invention where the above-described ideal seating arrangement has been achieved. For further familiarization of the ideal in the composite fabric structure of one embodiment of the present invention have been marked with an "o" and labeled "S". Once again, more or fewer self-stitching points could be utilized, provided they meet the ideal location criteria, depending upon the overall papermaking and structural requirements of the final composite forming fabric product. FIG. 6b, taken along line 6b--6b in FIG. 6a, and FIG. 6c, taken along line 6c--6c in FIG. 6a, illustrate two cross machine direction sections and FIG. 6d, taken along line 6d--6d in FIG. 6a, and FIG. 6e, taken along line 6e--6e in FIG. 6a, illustrate two machine direction sections of the preferred embodiment of the present invention.
FIGS. 6b and 6c illustrate the paths of the two distinct cross machine direction yarns the non-stitching yarn in the former and the stitching yarn in the latter, and clearly show the role and positioning of these alternating cross machine direction yarns in this fabric. The typical ideal seating arrangement previously described is apparent in the cross machine direction section in FIG. 6b where there is a stacked relationship between the cross machine direction yarns 14 of the top fabric layer 10 and the cross machine direction yarns 24 of the bottom fabric layer 20. In there is FIG. 6c, no bottom fabric layer 20 cross machine direction yarn 24 below the fabric layer 10 cross machine direction yarn 14 which in this case is a stitching yarn as-are all alternating top fabric layer 10 cross machine direction yarns 14. The typical ideal self-stitching point marked "S" is apparent in FIG. 6a, FIG. 6c and in FIG. 6e. In the embodiment of the present invention shown in FIGS. 6a-6e, the self-stitching is done by each self-stitching top fabric layer cross machine direction yarn 14 on every eighth bottom fabric layer machine direction yarn 22 so that, with the alternating nature of the stitching pattern, every machine direction yarn 22 in the bottom fabric layer 20 is eventually interlaced with every other cross machine direction yarn 14 from the top fabric layer 10 within the confines of one pattern repeat. It can also be seen that the self-stitch provided by every other fine cross machine direction yarn 14 from the top fabric layer 10 is merely an extension from its already down or under float position which allows it to descend somewhat further down to interlace with the machine direction yarn 22 in the bottom fabric layer 20 which is at that point in its highest position. At its highest position, or elevation, in its weave repeat, the machine direction yarn 22 in the bottom fabric 20 is optimally accessible. The elevation of representative machine direction yarns relative to each other in a weave repeat is shown in FIG. 2D. As can be seen in that figure, a possible stitch point occurs when the machine direction yarn is at a highest elevation compared to the other machine direction yarns in the weave repeat. This combination gives the minimal elongation of the self-stitch yarn over a symmetrically uniform path. Having the self-stitch cross machine direction yarn 14 of the top fabric layer 10 located midway between the surrounding cross machine direction yarns 24 in the bottom fabric layer 20 also contributes to the structural integrity of the resultant composite fabric (see FIG. 6e).
FIG. 7 illustrates the combined structure with the papermaking surface of the top fabric layer 10 overlaid on the interfacing surface of the bottom fabric layer 20 and the self-stitch points marked with an "o" and labeled "S". A typical ideal seating arrangement will produce a situation where the lower floats of the machine direction yarns 12 in the top fabric layer 10 interface with the upper float of the cross machine direction yarn 24 in the bottom fabric layer 20 in the required 90 degree cross-shaped orientation mode, as shown within the circled area. The skilled observer can see that this ideal seating arrangement condition occurs numerous times within a pattern repeat of the present invention. The ideal self-stitching points, marked "o" and labeled "S" typically, also occur quite frequently within a pattern repeat. However, in the preferred embodiment of the present invention, the utilized frequency of these ideal self-stitching points which exist along every other fine cross machine direction yarn 14 in the top fabric layer 10 is once every sixteen machine direction yarns 12 in the top fabric layer 10 and once every eight machine direction yarns 22 in the bottom fabric layer 20. Given the staggered nature of the self-stitching pattern, the net result is that at some point along every machine direction yarn 22 in the bottom fabric layer 20 an interlace is achieved with the top fabric layer 10 within a pattern repeat. This self-stitching frequency can be increased or decreased, always using the ideal self-stitching points only, depending upon the particular application for the final product.
FIGS. 8a and 8b illustrate the two configurations, non-stitching and stitching for the cross machine direction yarns 14 of the top fabric layer 10 as they relate to the bottom fabric layer 20 in the preferred embodiment of the present invention. FIG. 8a illustrates the cross machine direction yarns 14 of the composite fabric taken along line 8a--8a in FIG. 7 at the stacked, non-stitching position and FIG. 8b, taken along line 8b--8b in FIG. 7, shows the intermediately spaced self-stitching yarns cross machine direction yarn 14 of the top fabric layer 10. The typical ideal seating arrangement is circled and the typical self-stitching point is marked "o" and labeled "S".
Within the context of the present invention, only fabrics having 2×2 twill weaves have been illustrated herein; however, the teachings described herein are not restricted to just 2×2 twill weaves. In other words, the principles of ideal seating arrangement, self-stitch alignment, and interface symmetry can be successfully applied over a broad range of weave patterns, not necessarily the same for each layer, in creating similar composite papermaking fabrics. Where the espoused guidelines are judiciously applied, a superior papermaking product can be produced. While the fabric herein described constitutes the preferred embodiment of the invention, it is to be understood that the invention is not limited to the precise fabric described and that changes may be made herein without departing from the scope of the invention.
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A multi-layer self-stitched papermakers' fabric including a top fabric layer of relatively fine machine direction and cross machine direction yarns and a bottom fabric layer of relatively coarse machine direction and cross machine direction yarns, interwoven to produce seating and self-stitching conditions for optimal drainage. In a preferred embodiment, the top fabric layer has a right to left twill on its upper papermaking surface and the bottom fabric layer has a left to right twill on its upper interlacing surface.
The questions raised in reexamination request No. 90/003,352, filed Mar. 7, 1994, have been considered and the results thereof are reflected in this reissue which constitutes the reexamination certificate required by 35 U.S.C. 307 as provided in 37 CFR 1.570(e).
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application No. 61/203,860 filed on Dec. 30, 2008, which application is incorporated herein by reference in its entirety for all purposes.
TECHNICAL FIELD
The present invention relates generally to bioreactors and, more particularly, to algae growing bioreactors, assemblies and related systems for growing and cultivating algae and/or other micro-organisms.
BACKGROUND OF THE INVENTION
Algae has long been viewed as a nuisance and is often referred to as “pond scum.” However, it has also been known that micro algae can be a major resource. Spirulina , for instance, is noted as the food resource with the highest level of digestible protein of any plant source. Other species, of which there are many, are sources of medicines, dyes, alcohols, and lipids as well as proteins. Recently, with the concern over various issues related to fossil fuels, micro algae with its propensity for creating lipids (in some species 30% to 50% or more by weight) has become the focus of a renewable source for biodiesel.
The growth of algae depends on the nutrients in the water as well as the illumination that is available for producing photosynthesis. Nutrients for algae are developed, for example, as oxidation products in wastewater and sewage treatment plants operating with aeration. Algae take up these oxidation products, and the water is softened as well as disinfected. Thus, utilization of algae for purposes of water purification is a viable alternative for chemical removal of oxidation products. Water purified by algae can readily be recycled into the water supply.
Many parts of the world, particularly in higher latitudes with prevailing unfavorable weather conditions do not offer sufficient natural light to permit cleaning and clearing of water by means of growing algae. Instead, artificial light is needed at least as a supplement. Generally speaking, photochemical effectiveness of light increases with its intensity within a certain range, while for higher intensities one approaches a saturation level so that further increases in light intensity do not produce any gain in photochemical effectiveness.
Prior mass algae growing systems have yet to prove economical because (1) they require relatively deep containment (20-100 cm) in order to provide for temperature control; (2) they produce comparatively dilute cultures; (3) they make inefficient use of carbon dioxide and little use of direct sunlight; (4) they require substantial energy inputs to provide mixing to avoid thermal stratification; (5) they must process larger volumes of water to obtain the same harvest yields of algal matter that might be collectible from shallower systems; and (6) they permit little or no control and/or regulation of those environmental elements which control and regulate the performance characteristics of the cultured cells.
Accordingly, there is a need in the art for new and improved algae growing and cultivating systems. The present invention fulfills this need and provides for further related advantages.
SUMMARY OF THE INVENTION
In brief, the present invention relates to an ultra high intensity micro algal bioreactor designed to minimize the area foot print while completely controlling and optimizing the conditions for growing one or more specific strains of micro algae at maximum efficiency and minimum cost. The invention optimizes the algal exposure to light, natural and artificial, and maintains optimum water temperature while allowing the maximum absorption of carbon dioxide while cleaning sewage and other organic waste water streams of nutrients for the benefit of a sustainable environment, as well as an economic benefit to all stakeholders.
The present invention is also more specifically directed to an algae growing assembly for growing and cultivating algae. In one embodiment, the algae growing assembly comprises: a plurality of growing trays vertically stacked together and retained within a transparent housing, wherein each growing tray is configured to flowingly transport nutrient enriched water to one of the plurality of growing trays positioned immediately beneath it; a plurality of lights positioned in between the plurality of growing trays and within the transparent housing; and a carbon dioxide gas infusion system for adding carbon dioxide gas to the nutrient enriched water contained within each of the plurality of growing trays. Each of the plurality of growing trays may be characterized in that each is composed of a rigid or semi-rigid transparent plastic sheet having a pliable transparent gas permeable membrane affixed thereon. The rigid or semi-rigid transparent plastic sheet and the pliable transparent gas permeable membrane affixed thereon define, in the space between them, an inflatable carbon dioxide gas chamber, and wherein the carbon dioxide gas infusion system is fluidicly connected to each of the plurality of growing trays such that carbon dioxide gas is able to (1) inflate the carbon dioxide gas chamber of each of the plurality of growing trays, and (2) diffuse into the nutrient enriched water contained within each of the plurality of growing trays.
Objects of the invention include, but are not limited to: (1) intensification of the growing area to achieve maximum yield at a low cost; (2) dependable recovery of carbon dioxide from digesters and exhaust streams; (3) simplicity of structure and design so as to be feasible whether located on a farm, or in the heart of intensive population centers; (4) control of light and temperature for positive yield; (5) cleaning of water streams that have heretofore been considered contamination of natural water resources such as aquifers, streams, rivers, estuaries, ponds, lakes, seas and oceans; and (6) contributing to sustainable environments and economic feasibility.
These and other aspects of the present invention will become more readily apparent to those possessing ordinary skill in the art when reference is made to the following detailed description in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings are intended to be illustrative and symbolic representations of certain exemplary embodiments of the present invention and as such they are not necessarily drawn to scale. In addition, it is to be expressly understood that the relative dimensions and distances depicted in the drawings (and described in the “Detailed Description of the Invention” section) are exemplary and may be varied in numerous ways. Finally, like reference numerals have been used to designate like features throughout the several views of the drawings.
FIG. 1 illustrates a side elevational view of an algae growing assembly in accordance with an embodiment of the present invention.
FIG. 2 illustrates a side cross-sectional view of an algae growing assembly in accordance with an embodiment of the present invention.
FIG. 3A is an exploded side elevational view of an unfolded growing tray and its corresponding gas permeable membrane in accordance with an embodiment of the present invention.
FIG. 3B is a side elevational view of an unfolded growing tray together with a corresponding gas permeable membrane in accordance with an embodiment of the present invention, wherein the gas permeable membrane is positioned on top of the unfolded growing tray while being held in place by one or more glue lines.
FIG. 3C is a side elevational view of a folded growing tray together with a corresponding gas permeable membrane in accordance with an embodiment of the present invention, wherein the gas permeable membrane is positioned on top of the folded growing tray while being held in place by one or more glue lines.
FIG. 4 is a side elevational view of first and second growing trays positioned one on top of the other in accordance with an embodiment of the present invention, and wherein the gas permeable membrane is inflated.
FIG. 5 is a side cross-sectional view of the first and second growing trays positioned one on top of the other taken along line 5 - 5 of FIG. 4 .
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings wherein like references numerals have been used to designate like or corresponding elements, and more particularly to FIGS. 1 and 2 , the present invention in one embodiment is directed to an algae growing assembly 10 . As shown, the algae growing assembly 10 comprises a transparent housing structure 12 (having a front door 12 a and a plurality of openable side panels 12 b ) and configured to retain a plurality of vertically stacked algae growing trays 14 . Each growing tray 14 is removable and includes a spillway 16 positioned at one end 18 . Each growing tray is configured to flowingly transport nutrient enriched water 20 (not directly shown but depicted as dashed lines in FIG. 2 ) from one growing tray 14 to the growing tray 14 positioned immediately beneath it. More specifically, the plurality of vertically stacked algae growing trays 14 are each positioned such that the spillway 16 of one growing tray 14 is opposite from the spillway 16 of the growing tray 14 positioned both immediately beneath and above it. In this configuration and as shown, the nutrient enriched water 20 is able to gravity flow across each growing tray 14 and spill into the growing tray 14 positioned immediately beneath it. Thus, the nutrient enriched water 20 (that contains algae) is able to flow in a zigzag manner throughout the algae growing assembly 10 .
As best shown in FIG. 2 , a centrifugal pump filter unit 22 is used to pump, filter, and re-circulate the nutrient enriched water 20 . The nutrient enriched water 20 is first fed (together with seed algae or other suitable microorganism) into the algae growing assembly 10 by way of an inlet portal 24 positioned above the upper most growing tray 14 . The nutrient enriched water 20 is then allowed to gravity flow in a zigzag manner throughout the algae growing assembly 10 , and exit therefrom by way of an outlet portal 26 positioned at the bottom of the algae growing assembly 10 (and is then reintroduced back into the centrifugal pump filter unit 22 ). The centrifugal pump filter unit 22 processes the nutrient enriched water 20 so as (1) to remove accumulated wet solids 28 by way of a second outlet portal 30 , and (2) to re-circulate the remaining nutrient enriched water 20 back to the top of the algae growing assembly 10 . The remaining nutrient enriched water 20 is mixed with selected amounts of fresh nutrient enriched water 20 that is introduced into the system at a mixing zone 32 .
An important and novel aspect of the above-described algae growing assembly 10 resides in the construction and configuration of each of the plurality of vertically stacked algae growing trays 14 . More specifically, and with reference to FIGS. 3A-C , each growing tray 14 comprises a rigid or semi-rigid transparent sheet 14 a such as, for example, a polycarbonate or PLEXIGLASS, that has a gas permeable membrane 14 b bonded thereon. In this regard, FIGS. 3A-C illustrates an exploded side elevational view of a rigid or semi-rigid transparent sheet 14 a and its corresponding gas permeable membrane 14 b in accordance with an embodiment of the present invention. As best shown in FIG. 3B , the gas permeable membrane 14 b is positioned on top of the rigid or semi-rigid transparent sheet 14 a and is held in place by one or more glue lines 37 . Thus, FIG. 3B illustrates a side elevational view of an “unfolded” growing tray 14 . As best shown in FIG. 3C , the unfolded growing tray 14 is subsequently cut and folded to form an algae growing tray 14 having a spillway 16 positioned at one end 18 . As shown, the glue lines 37 of each of the plurality of growing trays 14 are positioned so as to form a serpentine path for subsequent CO 2 infusion into the system (described below).
In order to promote and enhance photosynthesis, the algae growing assembly 10 also includes a plurality of lights 36 and a carbon dioxide (CO 2 ) infusion system 38 . As shown and in a preferred embodiment, the plurality of lights 36 are a series of tube lights uniformly positioned above and below each of the plurality of vertically stacked algae growing trays 14 (except that there are no tube lights positioned above the upper most growing tray or below the bottom most growing tray—as shown). The plurality of lights 36 may be configured to be turned on and off intermittently and for selected durations. The CO 2 infusion system 38 includes a pump (not shown) that pumps CO 2 into opposite ends of each of the growing trays 14 by way of CO 2 inlet portals 15 (as best shown in FIG. 4 ). In this configuration, CO 2 is able to be pumped into each of the plurality of growing trays 14 so as to inflate the space between the rigid or semi-rigid transparent sheet 14 a and its corresponding gas permeable membrane 14 b . Because the gas permeable membrane 14 b allows the escape or infusion of CO 2 into the nutrient enriched water 20 when under positive pressure, the nutrient enriched water 20 is further enriched with CO 2 during operation.
Stated somewhat differently, each of the plurality of growing trays 14 is composed of a rigid or semi-rigid transparent plastic sheet 14 a having a pliable transparent gas permeable membrane 14 b affixed thereon. As best shown in FIG. 5 , the rigid or semi-rigid transparent plastic sheet 14 a and the pliable transparent gas permeable membrane 14 b affixed thereon define, in the space between them, an inflatable carbon dioxide gas chamber 17 . The carbon dioxide gas infusion system 38 is fluidicly connected to each of the plurality of growing trays (by way of tubing not shown for purposes of simplicity) such that carbon dioxide gas is able to (1) inflate the carbon dioxide gas chamber 17 of each of the plurality of growing trays 14 , and (2) diffuse into the nutrient enriched water 20 contained within each of the plurality of growing trays 14 . Each of the plurality of growing trays 14 generally also further comprises one or more glue lines positioned 37 along at least the outer edges of the pliable transparent gas permeable membrane 14 b and between the rigid transparent plastic sheet 14 a and the pliable transparent gas permeable membrane 14 b . The one or more glue lines 37 define a serpentine path within each of the respective inflatable carbon dioxide gas chambers 17 (associated with each of the plurality of growing trays 14 ).
The algae growing assembly 10 is scalable. The transparent housing structure 12 and each of the plurality of vertically stacked algae growing trays 14 are preferably made (at least in part) of a rigid or semi-rigid transparent material such as, for example, a polycarbonate or PLEXIGLASS, to thereby maximize exposure of the algae to light, both natural and artificial. In order to facilitate
For purposes of illustration and not restriction, the following Example demonstrates various aspects and utility of the present invention as conceived and contemplated by the inventor.
EXAMPLE
Each stack preferably contains 24 trays that are 3.25 inches deep (with a 0.25 inch spillway) by 12 feet long by 6 feet wide. Each tray (made of transparent material such as a clear plastic) may be directly connected to three of the four walls of the “transparent housing.” The fourth side of tray is preferably built with a 3 inch face and a lip (i.e., spillway) to allow the seeded algae growth media to spill down to the next level and so on. Each tray is reversed from the one immediately above it so that there is both light access to the tray above and the one below, and simultaneously to maximize the absorption of CO 2 that is introduced into the structure and to minimize the footprint while optimizing the concentration of growth media. Each such stack may occupy approximately 82 square feet of surface area, and may have the equivalent productive area of approximately 6,712 square feet of pond.
The apparatus as shown is represented as a rectangular structure although it could be a square, rectangular or polygonal structure as well. In one preferred embodiment, the algae growing system would contain 96 trays and be approximately 42 feet in height.
The growth media may be pre-seeded with the specific organism to be propagated and introduced into the uppermost level of the stack. The stack, or group of stacks, is preferably sized to allow for the introduction of 100 percent of the new daily volume on a continuous basis in addition to the recycling of 33.3% of the output from the bottom of the stack for reseeding.
Carbon dioxide may be introduced continuously from the bottom of the stack as a minimum, and possibly at a multiplicity of locations in accordance with the specific needs of the specific strain of organism being grown.
Continuous monitoring of such items as pH, N, P, K, CO 2 , O, H, pressure, temperature, and flow rates may be maintained on a continuous 24/7 basis for assurance of optimum growing and safety conditions.
A multiplicity of stacks may be maintained in a single large glass building.
A multiplicity of glass buildings may be located on 1 acre of land.
In one embodiment, a glass house would house approximately 50 stacks, wherein 6.3 of said stacks would be equivalent to 1 surface acre of pond. Therefore, each glass house would be the equivalent of approximately 7.94 acres of pond area.
In view of the foregoing, my invention relates to a vertical micro algal growing system wherein the apparatus consists of a closed environment formed by an enclosed structure housing a multiplicity of growing trays designed to minimize the footprint while maximizing the amount of growing area. The trays are designed and configured such that each tray has the optimum depth for maximum light penetration. The vertical micro algal growing system optimizes the absorption of introduced carbon dioxide. The vertical micro algal growing system is seeded from the top and is continuously harvested and reseeded while introducing the new nutrient growth media. Mirrored surfaces, e.g., Mylar or other light reflective surface, may be utilized to optimize exposure of the growing organisms to both natural and artificial light. The depth of the growing media may be controlled to optimize the combination of light, dark, nutrient and carbon dioxide as well as temperature for optimum, stable and predictable continuous growth and harvesting.
While the present invention has been described in the context of the embodiments illustrated and described herein, the invention may be embodied in other specific ways or in other specific forms without departing from its spirit or essential characteristics. Therefore, the described embodiments are to be considered in all respects as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing descriptions, and 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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The invention disclosed herein relates to an ultra high intensity micro algal bioreactor designed to minimize the area foot print while completely controlling and optimizing the conditions for growing one or more specific strains of micro algae at maximum efficiency and minimum cost. The innovative bioreactor is in the form of an algae growing assembly that comprises a plurality of growing trays vertically stacked together and retained within a transparent housing. Each growing tray is configured to flowingly transport nutrient enriched water to the growing tray positioned immediately beneath it. Each growing tray is composed of a stiff transparent plastic sheet having a pliable transparent gas permeable membrane affixed thereon. A carbon dioxide gas infusion system is fluidicly connected to each of the plurality of growing trays such that carbon dioxide gas is able to (1) inflate respective carbon dioxide gas chambers, and (2) diffuse into the nutrient enriched water.
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FIELD OF THE INVENTION
[0001] This application is related to the field of network page management and more specifically to a method and system for dynamically establishing a web site home page in a desired language.
BACKGROUND OF THE INVENTION
[0002] Since its advent, the use of public networks, such as the Internet and the World Wide Web (www), has become a significant tool for companies to distribute information regarding their products and services. Many companies that sell or advertise their products to the general public, whether locally or in the international community, commonly use a portal homepage that allows their customers to view the contents of the entire web site in a particular language. Conventionally, the portal homepage is in a language that is classified as a default language and the user is provided with a link to a homepage in a then desired language. Hence, a user must first sign on to the web site and then select a particular or desired language homepage before obtaining information regarding the company's products or services.
[0003] While this method enables the company to respond to local language desires, the maintenance of the web page in multiple languages is a significant burden on company resources. When products or services are changed, added or deleted, associated web pages, in each language, must be updated to reflect such changes.
[0004] Accordingly, there is a need for a method and a system for reducing the burden imposed by multiple language web sites and the ability to simplify the updating of such web sites.
SUMMARY OF THE INVENTION
[0005] A method and system to allow a user to select a web site home page in a desired language is disclosed. The method comprises the steps of identifying within a web address request a directional information item, providing a web page associated with the web address to a second web site corresponding to said directional informational item, wherein the second web site includes a language translator, translating the web page textual information in accordance with the language translator and returning the translated web page to the user. The method further comprises the steps of accessing a control table to determine a status of the web page and obtaining a version of the web page stored locally on the second site, when said status indicates said web page is locally stored and valid, otherwise obtaining a current version of the web page; and translating the obtained web page.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 illustrates a block diagram of an exemplary process for selecting desired homepage language in accordance with the principles of the invention;
[0007] FIG. 2 illustrates in further detail the processing shown in FIG. 1 ;
[0008] FIG. 3 illustrates a flow chart providing detail of the processing shown in FIGS. 1 and 2 ; and
[0009] FIG. 4 illustrates a system for implementing the process illustrated in FIGS. 1-3 .
[0010] It is to be understood that these drawings are solely for purposes of illustrating the concepts of the invention and are not intended as a definition of the limits of the invention. The embodiments shown in FIGS. 1-4 and described in the accompanying detailed description are to be used as illustrative embodiments and should not be construed as the only manner of practicing the invention. Also, the same reference numerals, possibly supplemented with reference characters where appropriate, have been used to identify similar elements.
DETAILED DESCRIPTION OF THE INVENTION
[0011] FIG. 1 illustrates a block diagram of an exemplary process 100 for selecting desired homepage language in accordance with the principles of the invention. In this exemplary process, browser software 110 on client computer 115 transmits a request, using a web address or a URL, over network 120 to server 125 . Server 125 , in this case, is representative of a proxy to the host web designated in the transmitted address or URL. Server 125 includes language recognizer software 130 that extracts information from the address or URL and directs the request based on the information extracted from the request. More specifically, the language recognizer software 130 determines whether information in the request is associated with a site language cookie that has previously been stored on client computer 115 . Cookie technology is well known in the art of networking and need not be discussed in detail herein.
[0012] If language recognizer software 130 determines that site language cookie information is not available, the request is directed to a default web site 140 . In this illustrated case, the default web site 140 is maintained in a traditional Chinese language 145 . However, if the language recognizer software 130 determines site language cookie information is available, then the request is directed to the appropriate language virtual web site, shown as web sites 150 and 155 . In this illustrative case site 150 may be associated with a web site that is maintained in a simple Chinese language while site 155 may be associated with a web site maintained in Japanese. Although only two alternate language web sites are shown, it would be recognized by those skilled in the art that the present invention is not limited to only the two sites shown but many contain any number of alternate language web sites.
[0013] FIG. 2 illustrates in further detail processing 100 shown in FIG. 1 . In this case, browser software 110 provides a request to web server language recognizer software 130 as previously discussed. Language recognizer software 130 extracts desired data from the address and language information from a URI table (not shown), which provides information regarding the desired web page and includes information regarding addresses of alternate web sites or instructions that provide direction regarding language conversion processing. For example, the URI table may include information that a desired web page is stored on a local web server (i.e., local mode) and this page is not suitable for language translation or conversion. In another aspect, the URI table may indicate that a desired web page is always obtained from a language converter program. Furthermore, in one case, the web page may be referred to a “no-cache” page as the desired web page may change. In another case, the ability to access the desired web page may have expired and must again be read. In this case, access to the desired web page may be made through information stored in a “cache” memory and is referred to as a “cache” page.
[0014] As would be appreciated, the language recognizer software may be resident on the proxy server 125 or on a second server (not shown). Dependent upon the desired language information, a basic web page may be provided as represented by web server or site 140 , as in this illustrated example, when the desired language information in the URI table is determined to be “ZH-BIG5”. However, if the desired language information is determined to be “GB2312” or “JP-EUC,” the request is directed to either web site 150 , e.g., simple Chinese, or web site 155 , e.g., Japanese, respectively. Web sites 150 and 155 may further include language plug-in software 152 and 157 , respectively. Language plug-in software is operable to translate or convert the information on a provided basic web page to the appropriate language. The converted web page is then provided to the browser software 110 for viewing on the user's computer.
[0015] FIG. 3 illustrates a process 300 that provides further detail of the processing shown in FIGS. 1 and 2 . In this case, when a URI attribute table is received at the web site containing a language conversion plug-in, the URI attribute table is analyzed to determine a next process step.
[0016] If the URI attribute table indicates that the desired web site is a “no-cache mode” site, at block 310 , then the existing web page received from the web server is translated into the appropriate language, at block 315 , and returned to browser software 110 . If, however, it is not a “no-cache mode” site, a determination is made at block 320 whether the web site associated with the URI is local to the web site. If the web site is not indicated to be local, then the web page is reloaded at block 322 , translated at block 324 and saved as a local entry at block 326 .
[0017] However, if the web site is indicated to be local, a determination is made at block 330 whether the locally stored web site is still valid. For example, the determination may check whether the time the local file was last modified is less than a storage time associated with the base web page. If the local is valid then the file is translated at block 335 and returned to browser software. Otherwise, the base web page is reloaded, translated and returned to browser software.
[0018] In another aspect of the process shown in FIG. 1 , the URI attribute table may be updated periodically, preferably on an hourly basis. This periodic update process allows an administrator or web master to manually update the URI attribute table for different purposes. For example, pages may be personalized or different style pages may be used as local pages. In this periodic update, the modification time of base web pages may also be updated.
[0019] FIG. 4 illustrates a system 400 for implementing the principles of the invention as depicted in the exemplary processing shown in FIGS. 1-3 . In this exemplary system embodiment 400 , input data is received from sources 405 over network 450 and is processed in accordance with one or more software programs executed by processing system 410 . Processor 410 may be representative of a handheld calculator, special purpose or general purpose processing system, desktop computer, laptop computer, palm computer, or personal digital assistant (PDA) device, etc., as well as portions or combinations of these and other devices that can perform the operations illustrated in FIGS. 1-3 . The results of processing system 510 may then be transmitted over network 470 for viewing on display 480 , reporting device 490 and/or a second processing system 495 .
[0020] Specifically, processing system 410 includes one or more input/output devices 540 that receive data from the illustrated source devices 405 over network 450 . The received data may then be applied to processor 420 , which is in communication with input/output device 440 and memory 430 . Processor 420 may be a central processing unit (CPU) or dedicated hardware/software, such as a PAL, ASIC, FGPA, operable to execute computer instruction code or a combination of code and logical operations. Input/output devices 440 , processor 420 and memory 430 may communicate over a communication medium 425 . Communication medium 425 may represent a communication network, e.g., ISA, PCI, PCMCIA bus, one or more internal connections of a circuit, circuit card or other device, as well as portions and combinations of these and other communication media.
[0021] In one embodiment, processor 420 may include code which, when executed, performs the operations illustrated herein. The code may be contained in memory 430 , read or downloaded from a memory medium such as a CD-ROM or floppy disk represented as 483 , or provided by manual input device 485 , such as a keyboard or a keypad entry, or read from a magnetic or optical medium (not shown) which is accessible by processor 420 , when needed. Information items provided by input device 483 , 485 and/or magnetic medium may be accessible to processor 420 through input/output device 440 , as shown. Further, the data received by input/output device 440 may be immediately accessible by processor 420 or may be stored in memory 430 . Processor 420 may further provide the results of the processing shown herein to display 480 , recording device 490 or a second processing unit 495 through I/O device 440 .
[0022] As one skilled in the art would recognize, the terms processor, processing system, computer or computer system may represent one or more processing units in communication with one or more memory units and other devices, e.g., peripherals, connected electronically to and communicating with the at least one processing unit. Furthermore, the devices illustrated may be electronically connected to the one or more processing units via internal busses, e.g., serial, parallel, ISA bus, microchannel bus, PCI bus, PCMCIA bus, USB, wireless, infrared, radio frequency, etc., or one or more internal connections of a circuit, circuit card or other device, as well as portions and combinations of these and other communication media, or an external network, e.g., the Internet and Intranet. In other embodiments, hardware circuitry may be used in place of, or in combination with, software instructions to implement the invention. For example, the elements illustrated herein may also be implemented as discrete hardware elements or may be integrated into a single unit.
[0023] As would be understood, the operations illustrated in FIGS. 2-5 may be performed sequentially or in parallel using one or several different processors to determine specific values. Processor system 410 may also be in two-way communication with each of the sources 405 . Processor system 410 may further receive or transmit data over one or more network connections from a server or servers over, e.g., a global computer communications network such as the Internet, Intranet, a wide area network (WAN), a metropolitan area network (MAN), a local area network (LAN), a terrestrial broadcast system, a cable network, a satellite network, a wireless network, or a telephone network (POTS), as well as portions or combinations of these and other types of networks. As will be appreciated, networks 450 and 470 may also be internal networks or one or more internal connections of a circuit, circuit card or other device, as well as portions and combinations of these and other communication media or an external network, e.g., the Internet and Intranet.
[0024] While there has been shown, described, and pointed out fundamental novel features of the present invention as applied to preferred embodiments thereof, it will be understood that various omissions and substitutions and changes in the apparatus described, in the form and details of the devices disclosed, and in their operation, may be made by those skilled in the art without departing from the spirit of the present invention. It is expressly intended that all combinations of those elements that perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Substitutions of elements from one described embodiment to another are also fully intended and contemplated.
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A method and system to allow a user to select a web site home page in a desired language is disclosed. The method comprises the steps of identifying within a web address request a directional information item, providing a web page associated with the web address to a second web site corresponding to said directional information item, wherein the second web site includes a language translator, translating the web page textual information in accordance with the language translator and returning the translated web page to the user. The method further comprises the steps of accessing a control table to determine a status of the web page and obtaining a version of the web page stored locally on the second site, when said status indicates said web page is locally stored and valid, otherwise obtaining a current version of the web page; and translating the obtained web page.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from U.S. Provisional Application Ser. No. 62/014,781 filed on Jun. 20, 2014, and U.S. Provisional Application Ser. No. 62/034,309 filed on Aug. 7, 2014, the entire disclosures of which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The invention relates to systems and methods for recovering used drilling fluids from drill cuttings generated by oil and gas drilling operations.
BACKGROUND OF THE INVENTION
[0003] The loss of drilling fluids presents several technological and cost challenges to the energy exploration industry. These challenges generally include the seepage losses of drilling fluids to the formation, the recovery of drilling fluids at surface and/or the disposal of drilling detritus or cuttings that are contaminated with drilling fluid. In the context of this description, “drilling fluid” is both fluid prepared at surface used in an unaltered state for drilling as well as all fluids recovered from a well that may include various contaminants from the well including water and hydrocarbons (both liquid and gas
[0004] As is known, and by way of background, during the excavation or drilling process, drilling fluid losses can reach levels approaching 300 cubic meters of lost drilling fluid over the course of a drilling program. With some drilling fluids having values in excess of $1600 per cubic meter, the loss of such volumes of fluids represents a substantial cost to drill operators.
[0005] Drilling fluids are generally characterized as either “water-based” or “oil-based” drilling fluids that may include many expensive and specialized chemicals as known to those skilled in the art. As a result, it is desirable that minimal quantities of drilling fluids are lost during a drilling program such that many technologies have been considered and/or employed to minimize drilling fluid losses both downhole and at surface.
[0006] Additionally, in some areas the delivery of oil or water for the formulation of drilling fluids can present several costly challenges for some operations; specifically desert, offshore and even some districts where communities will not allow allocation of water for this use.
[0007] As noted above, one particular problem is the separation of drilling fluid and any hydrocarbons from the formation that may be adhered to the drill cuttings (collectively “fluids”) at the surface. The effective separation of various fluids from drill cuttings has been achieved by various technologies including but not limited to; hydrocyclones, mud cleaners, linear motion shakers, scroll centrifuges, vertical basket centrifuges (VBC), vacuum devices, and vortex separators. As known to those skilled in the art, these devices are typically rented by operators at costs ranging from $1000 to $2000 per day and, as a result, can also represent a significant cost to operators. Thus, the recovery of fluids necessary to recover these costs generally requires that the recovered fluid value is greater than the equipment rental cost in order for the recovery technology to be economically justified. On excavation projects where large amounts of high-cost drilling fluid are being lost (for example in excess of 3 cubic meters per day), then daily rental charges for specialized separation equipment can provide favorable economics. In addition, an operator will likely also factor in the environmental effects and/or costs of disposal of drilling fluid contaminated drill cuttings in designing their drilling fluids/drill cutting separation/recovery systems.
[0008] Further still, past techniques for separating drilling fluid from drill cuttings have also used liquid spraying systems to deliver “washing” liquids to drill cuttings as they are processed over shaker equipment. Such washing liquids and associated fluid supply systems are used to deliver various washing fluids as the cuttings are processed over a shaker and can include a wide variety of designs to deliver different washing fluids depending on the type of drilling fluid being processed. For example, washing liquids may be comprised of oil, water, or glycol depending on the drilling fluid and drill cuttings being processed over the shaker. Generally, these washing fluids are applied to reduce the viscosity and/or surface tension of the fluids adhered to the cuttings and allow for more fluids to be recovered. However, these techniques have generally been unable to be cost effective for many drilling fluids as the use of diluting fluids often produces unacceptable increases in drilling fluid volume and/or changes in chemical consistency and, hence, rheological properties of the drilling fluid.
[0009] Thus, while various separation systems are often effective and/or efficient in achieving a certain level of fluids/cuttings separations, each form of separation technology can generally only be efficiently operated within a certain range of conditions or parameters and at particular price points. For example, standard shakers utilizing screens are relatively efficient and consistent in removing a certain amount of drilling fluid from cuttings where, during the typical operation of a shaker, an operator will generally be able to effect drilling fluid/cuttings separation to a level of about 12-40% by weight of fluids relative to the drill cuttings (i.e. 12-40% of the total mass of recovered cuttings is drilling fluid). The range of fluids/cuttings wt % is generally controlled by screen size wherein an operator can effect a higher degree of fluids/cuttings separation by using a larger screen opening (eg. 50-75 mesh) and a lower degree of fluids/cuttings separation with a smaller screen opening (eg. up to 325 mesh), The trade-off between using a large mesh screen vs. a small mesh screen is the effect of mesh screen size on the quantity of solids passing through the screen and the time required to effect that separation. That is, while an operator may be able to lower the fluids retained on cuttings coming off the shaker with a larger mesh screen (50-75 mesh), the problem with a larger mesh screen is that substantially greater quantities of solids will pass through the screen, that then significantly affect the rheology and density of the recovered fluids and/or require the use of an additional and potentially less efficient separation technology to remove those solids from the recovered drilling fluids. Conversely, using a small mesh screen, while potentially minimizing the need for further downstream separation techniques to remove solids from recovered drilling fluids, results in substantially larger volumes of drilling fluids not being recovered, as they are more likely to pass over the screens hence leading to increased drilling fluids losses and/or require subsequent processing.
[0010] Accordingly, in many operations, an operator will condition fluid recovered from a shaker to additional processing with a centrifugal force type device in order to reduce the fluid density and remove as much of the fine solids as possible before re-cycling or reclaiming the drilling fluid. However, such conditioning requires more expensive equipment such as centrifuges, scrolling centrifuges, hydrocyclones, etc., which then contribute to the overall cost of recovery. These processing techniques are also directly affected by the quality of the fluid they are processing, so fluids pre-processed by shakers using a coarse screen will not be as optimized as those received from finer screens.
[0011] Furthermore, the performance of centrifuges and hydrocyclones and other equipment are directly affected by the viscosity and density of the feed fluid. As a result, drilling fluid recovery techniques that send heavy, solids-laden fluids to secondary processing equipment require more aggressive techniques such as increased g-forces and/or vacuum to effect separation which will typically cause degradation in the drill cuttings.
[0012] Further still, such secondary processing equipment typically cannot process drill cuttings and drilling fluids at the same throughput values of a shaker with the result being that additional separation equipment may be required or storage tanks may be required to temporarily hold accumulated drilling fluid.
[0013] Thus, the operator will try to balance the cost of drilling fluid losses with the quality of the fluid that is recovered together with other considerations. While operators will typically have little choice in the quality of the cuttings processing and fluid recovery techniques available, many operators will operate separation equipment such that the recovered drilling fluid density from the separation equipment will be about 200-300 kg/m 3 heavier than the density of the circulating fluid in the system. This heavier fluid which would contain significant quantities of fine solids and that when left in the drilling fluid will either immediately or over time impair the performance of the drilling fluid or any other type of fluid.
[0014] As a result, there continues to be a need for systems that economically increase the volume of fluids recovered from a shaker without negatively impacting the rheological properties of the recovered drilling fluid.
[0015] In addition, there has been a need to develop low-cost retrofit technologies that can enhance fluid recovery and do so at a fractional cost level to mechanisms and technologies currently employed. Further, there has been a need for retro-fit technologies that can be utilized on a variety of shakers from different manufactures and that can be used to enhance the operation of existing shakers.
[0016] The use of vacuum technology has been one solution to improving the separation of drilling fluids. However, vacuum technologies may also present dust and mist problems in the workplace. With past vacuum techniques there is a need to regularly clean clogged screens with high pressure washes. High pressure washing of screens creates airborne dust and mist hazards to operators. Thus, there continues to be a need for technologies that minimize the requirement for screen washing.
[0017] Further still, there has been a need for improved fluid separation systems on the underside of a vacuum screen that allows relatively large volumes of air to be drawn through a vacuum screen to be effectively and efficiently separated from the relatively low volume of drilling fluid being drawn through a vacuum screen. That is, there has been a need for improved fluid/air separation systems.
[0018] Further still, there has been a need for retrofit systems that can be adapted to standard shakers without substantial modification to the existing shaking and that allow for quick and easy installation at a job site. In addition, there has been a need for retrofit systems that also allow for ready disassembly of the system for transport and/or maintenance.
[0019] As is known, the entry of gas from a formation into circulating drill fluid occurs regularly during drilling operations where pressurized gasses from the formation mix with the circulating drilling fluid and dissolve within the drilling fluid which depending on the quantity and pressures may fully saturate the drilling fluid. This is particularly true as a drill bit enters a pay-zone within the formation and there is an influx of formation gas into the well bore which will lead to a saturation of drilling fluid with the formation gas. As the drilling fluid rises to the surface and is depressurized, gas may be released from the drilling fluid.
[0020] As a result, there has also been a need for systems that improve the ability of shaker systems to improve gas/fluid separation at a shaker. Currently used systems typically include a vacuum conduit running from the shaker screen connection to a large recovery tank which is in line with a powerful vacuum system. According to normal operations, the vacuum systems run continuously until the large tanks become filled with recovered drilling fluid, at which point the recovered drilling fluid is pumped out of the recovery tank and conveyed to the main drilling fluid supply vessels which are known as “mud tanks.” Improved systems which reduce the complexity of fluid transfer and related energy requirements are desirable.
[0021] Various technologies including vacuum technologies have been used in the past for separating drilling fluids from drill cuttings including vibratory shakers.
[0022] For example, U.S. Pat. No. 4,350,591 describes a drilling mud cleaning apparatus having an inclined travelling belt screen and degassing apparatus including a hood and blower. U.S. Patent Publication No. 2008/0078700 discloses a self-cleaning vibratory shaker having retro-fit spray nozzles for cleaning the screens. Canadian Patent Application No. 2,664,173 describes a shaker with a pressure differential system that applies a non-continuous pressure across the screen. U.S. Pat. No. 4,639,258 and U.S. Patent Publication Nos. 2014/0110357, 2014/0091028 and 2013/0074360 describe vacuum-assisted shale shakers. U.S. Pat. No. 8,691,097 describes a separating tower with a top vacuum discharge port and a bottom solids discharge port. Other references including U.S. Pat. No. 6,092,390, U.S. Pat. No. 6,170,580, U.S. Patent Publication 2006/0113220 and PCT Publication No. 2005/054623 describe various other separation technologies. Each of the above-noted references is incorporated herein by reference in entirety.
[0023] Thus, while past technologies may be effective to a certain degree in enabling drilling fluid/cuttings separation, the prior art is silent in aspects of the design and operation of alternative separation devices that enable expedient conveyance of the collected drilling fluid in a convenient and cost-effective manner with minimal equipment requirements.
SUMMARY OF THE INVENTION
[0024] In accordance with one aspect of the present invention, there is provided a system for recovering used drilling fluid from drill cuttings being processed on a shaker screen, the system comprising: a vacuum screen attachment operatively connected to the underside of the shaker screen, the vacuum screen attachment operatively connected to a vacuum source by a vacuum conduit; a hydrostatic chamber located in the vacuum conduit downstream of the vacuum screen attachment, the hydrostatic chamber having a fluid dump port at or adjacent to its bottom surface; a means for setting a limit of fluid accumulation in the hydrostatic chamber, wherein fluid dumps from the fluid dump port when the limit of fluid accumulation is reached; and a conduit for conveying the fluid dumped from the fluid dump port to a storage tank.
[0025] In certain embodiments, the means for setting the limit of fluid accumulation comprises: one or more fluid level sensors configured to identify one or more specific levels of fluid inside the hydrostatic chamber; a vacuum controller for running and shutting off the vacuum source, the controller in communication with the sensors and configured to stop the vacuum source when one of the one or more specific levels of fluid is reached; and a valve connected to the fluid dump port and configured to prevent dumping of fluid from the fluid dump port when the vacuum source is running and further configured to allow dumping of fluid when the vacuum source is shut off.
[0026] In certain embodiments, the sensors include a first fluid level sensor and a second fluid level sensor, each located within the hydrostatic chamber, wherein the first fluid level sensor. is located above the second fluid level sensor.
[0027] In certain embodiments, the valve is a passive flapper valve.
[0028] In certain embodiments, the system further comprises a float valve in the hydrostatic chamber above the first fluid level sensor, the float valve configured to shut off the vacuum source if either or both of the sensors fail and fluid reaches and activates the float valve.
[0029] In certain embodiments, the system further includes a fluid separator located in the vacuum conduit between the hydrostatic chamber and the vacuum source, the fluid separator provided to prevent entry of fluid into the vacuum source.
[0030] In certain embodiments, the fluid separator is a cyclone separator provided with a lower port for exit of waste fluid collected therein.
[0031] In certain embodiments, the system further includes one or more filters located in the vacuum conduit between the fluid separator and the vacuum source.
[0032] In certain embodiments, the hydrostatic chamber is cylindrical.
[0033] In certain embodiments, the vacuum source is connected to the hydrostatic chamber at the top of the hydrostatic chamber.
[0034] In certain embodiments, the vacuum source is a regenerative fan blower.
[0035] In certain embodiments, the means for setting the limit of fluid accumulation in the hydrostatic chamber is provided by a vacuum equalization tube having a first connection to the interior of the hydrostatic chamber at or adjacent to the bottom of the hydrostatic chamber and a second connection to the interior of the hydrostatic chamber located above the first connection, wherein the fluid dump port allows entry of air into the hydrostatic chamber and into the vacuum equalization tube under force of the vacuum source and allows exit of fluid from the hydrostatic chamber and vacuum equalization tube induced by a reduction of vacuum force at the fluid dump port produced by the vacuum equalization tube and by the force of gravity acting on the hydrostatic head of the fluid in the hydrostatic chamber when the force of gravity on the hydrostatic head exceeds the force of air entering the system through the fluid dump port.
[0036] In certain embodiments, the system further includes a second fluid dump port located in the vacuum conduit either upstream or downstream from the hydrostatic chamber.
[0037] In certain embodiments, the second fluid dump port is located in the vacuum conduit between the vacuum screen attachment and the hydrostatic chamber, wherein the second fluid dump port allows entry of air into the vacuum conduit under force of the vacuum source and exit of fluid from the vacuum conduit through the second fluid dump port induced by the force of gravity acting on the weight of the fluid above the second fluid dump port.
[0038] In certain embodiments, the second fluid dump port is located in a conduit connector unit, the connector unit having a connection to at least one vacuum screen attachment and a connection to the vacuum source.
[0039] In certain embodiments, the conduit connector Unit comprises two or more connections to two or more vacuum screen attachments.
[0040] In certain embodiments, the second fluid dump port is provided with a choke mechanism for reducing the pressure of the air flow into the vacuum conduit under force provided by the vacuum source.
[0041] In certain embodiments, the second connection of the vacuum equalization tube to the hydrostatic chamber is located adjacent the top of the hydrostatic chamber.
[0042] In certain embodiments, the hydrostatic chamber is cylindrical.
[0043] In certain embodiments, the inner sidewall of the hydrostatic chamber is provided with a series of downwardly angled baffles to provide resistance to upward movement of fluids under the force of vacuum from the vacuum source.
[0044] In certain embodiments, the vacuum source is connected to the hydrostatic chamber at the top of the hydrostatic chamber.
[0045] In certain embodiments, the system further includes a fluid separator located in the vacuum conduit between the hydrostatic chamber and the vacuum source, the fluid separator provided to prevent entry of fluid into the vacuum source.
[0046] In certain embodiments, the system further includes a shut-off switch attached at an intermediate vertical position of the inner sidewall of the liquid separator, the shut-off switch for shutting off the vacuum source when the fluid level inside the fluid separator reaches the level of the shut-off switch.
[0047] In certain embodiments, the system further includes a third fluid dump port located in the vacuum conduit downstream of the liquid separator, the third fluid dump port configured to dump fluid accumulating in the liquid separator when the shut-off switch is engaged and the vacuum system is shut off.
[0048] In certain embodiments, the system further includes a vent valve located in the vacuum conduit between the hydrostatic chamber and the liquid separator.
[0049] In certain embodiments, the system further includes a shut-off switch in electronic communication with the vacuum source and automatically programmed to shut off the vacuum source at pre-determined intervals for a pre-determined period of time for the purpose of displacing the drill cuttings from the shaker screen by compensating reflexive motion of the shaker screen.
[0050] In certain embodiments, the vacuum source is a regenerative fan blower.
[0051] Another aspect of the present invention is a method for recovering used drilling fluid from drill cuttings being processed on a shaker screen, the method comprising the steps of: connecting a vacuum source to the underside of the shaker screen with a vacuum screen attachment, the vacuum source providing vacuum force to the underside of the shaker screen; installing a hydrostatic chamber in the vacuum conduit between the vacuum screen attachment and the vacuum source; providing a fluid dump port and valve in fluid communication with the hydrostatic chamber, the fluid dump port and valve allowing exit of fluid from the hydrostatic chamber induced by a reduction of vacuum force within the hydrostatic chamber and by the force of gravity acting on the hydrostatic head of the fluid in the hydrostatic chamber when the vacuum force is reduced; and activating the vacuum source until a pre-determined level of fluid is contained in the hydrostatic chamber, wherein the pre-determined level of fluid causes the fluid to drain from the fluid dump port.
[0052] In certain embodiments, the pre-determined level of fluid is identified by a sensor.
[0053] In certain embodiments, the identification of the pre-determined level of fluid by the sensor shuts off the vacuum source.
[0054] In certain embodiments, the pre-determined level of fluid is reached when the force of gravity acting on the hydrostatic head of the fluid exceeds the force of air entering the fluid dump port under vacuum provided by the vacuum source.
[0055] In certain embodiments, the method further includes providing a second fluid dump port in the vacuum conduit either upstream or downstream from the hydrostatic chamber and recovering the fluid dumping from the second fluid dump port.
[0056] In certain embodiments, the second fluid dump port is located in the vacuum conduit between the vacuum screen attachment and the hydrostatic chamber, the second fluid dump port allowing entry of air into the vacuum conduit under force of the vacuum source and exit of fluid from the vacuum conduit through the second fluid dump port induced by the force of gravity acting on the weight of the fluid above the second fluid dump port.
[0057] In certain embodiments, the second fluid dump port is located in a conduit connector unit, the connector unit having a connection to at least one vacuum screen attachment and a connection to the vacuum source.
[0058] In certain embodiments, the conduit connector unit comprises two Cr more connections to two or more vacuum screen attachments.
[0059] In certain embodiments, the second fluid dump port is provided with a choke mechanism for reducing the pressure of the air flow into the vacuum conduit under force provided by the vacuum source.
[0060] In certain embodiments, the inner sidewall of the hydrostatic chamber is provided with a series of downwardly angled baffles to provide resistance to upward movement of fluids under the force of vacuum from the vacuum source.
[0061] In certain embodiments, the vacuum source is connected to the hydrostatic chamber at the top of the hydrostatic chamber.
[0062] In certain embodiments, a fluid separator is provided in the vacuum conduit between the hydrostatic chamber and the vacuum source, the fluid separator provided to prevent entry of fluid into the vacuum source.
[0063] In certain embodiments, the vacuum source is a regenerative fan blower.
BRIEF DESCRIPTION OF THE DRAWINGS
[0064] Various objects, features and advantages of the invention will be apparent from the following description of particular embodiments of the invention, as illustrated in the accompanying drawings. The drawings are not necessarily to scale. Instead, emphasis is placed upon illustrating the principles of various embodiments of the invention. Similar reference numerals indicate similar components.
[0065] FIG. 1A is a plan view of a platform supporting a vacuum system and drilling fluid recovery tank as currently used in the prior art.
[0066] FIG. 1B is a perspective view of the same platform shown in FIG. 1A .
[0067] FIG. 2 is a schematic view of a system for recovering drilling fluid according to one embodiment of the present invention.
[0068] FIG. 3 is a schematic view of a system for recovering drilling fluid according to another embodiment of the present invention.
[0069] FIG. 4 is a schematic view of a system for recovering drilling fluid according to another embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Rationale
[0070] As noted in the background section, presently used vacuum-enhanced shaker systems connect to the underside of the screens of the shakers and apply vacuum to the underside of a portion of the screen. The fluids recovered from these systems are typically conveyed to a large holding tank which is in-line with the vacuum pump. The tank fills with recovered drilling fluid after the vacuum pump pulls the fluid from the cuttings on the screen and conveys it to the tank. When the tank is full of fluid recovered from the cuttings on the shaker screens, the fluid is pumped to the main drilling fluid supply tanks (which are known in the art as “mud tanks”) to contribute to the supply of drilling fluid used to drill the well. A representative prior art vacuum and tank system is shown in FIG. 1 . It is seen that the vacuum tank and vacuum system are supported by a large frame which represents a significant footprint at a drilling site. Representative characteristics of a typical tank and vacuum system include the following: tank volume 1.12 m 3 , horsepower of vacuum motor 25 HP, maximum pump rate 325 CFM (cubic feet per minute), total weight of tank and vacuum system 5300 lbs, footprint 8.5 feet×6.5 feet, height 8.75 feet, power rating to operate: 480 volts AC, 60 amps. The approximate retail cost of producing a typical vacuum and tank unit is $50,000 (CAD) and these units will be typically rented by drilling operators at a cost of $750 to $1000 (CAD) per day. These units incur significant shipping and delivery costs due to their weight and size.
[0071] The inventors have surprisingly discovered that providing a vacuum-based fluid recovery system with the capability to control the balance between the force of air influx into the vacuum conduit and the force of gravity acting on fluid within the vacuum conduit provides a means for dumping and recovery of drilling fluid at one or more dump ports. Additionally, the force of gravity can be used to dump drilling fluid under control of a fluid sensor. When such dump ports are provided at locations relatively close to the shaker screens, fluid can be dumped (and recovered) from the vacuum conduit at an early stage, thereby reducing the vacuum force required to move the drilling fluid over a longer distance, as required in prior art tank systems. As a result, a less powerful vacuum system may be employed, thereby reducing equipment costs, energy requirements and footprint. In certain embodiments discussed in detail below, the power requirements are reduced by about 90%. In addition, dumping of fluid directly to a conduit connected to the mud tanks obviates the need for the large intermediate fluid storage tank. As a result, the present invention thus provides a simpler and significantly less costly alternative to the prior art tank and vacuum system.
[0072] It is currently estimated that the components of the system provided according to certain aspects of the invention weigh as little as about 200 lbs and have a much smaller footprint as well as being of simple construction, thereby significantly simplifying efforts relating to maintenance and repairs. It may be possible to deliver components of the present system to drilling sites via aircraft and/or light-duty vehicles instead of using large transport trucks. It may also be possible to deliver the components of the system to drilling sites by a commercial courier service. This provides a significant advantage in terms of deployment costs. It is also expected that the simplicity of the system will allow it to be easily integrated with existing equipment at essentially any drilling site where recovery of drilling fluids is desired.
DESCRIPTION OF EXAMPLE EMBODIMENTS
[0073] Various aspects of the invention will now be described with reference to the figures. For the purposes of illustration, components depicted in the figures are not necessarily drawn to scale. Instead, emphasis is placed on highlighting the various contributions of the components to the functionality of various aspects of the invention. A number of possible alternative features are introduced during the course of this description. It is to be understood that, according to the knowledge and judgment of persons skilled in the art, such alternative features may be substituted in various combinations to arrive at different embodiments of the present invention.
Example 1
Drill Fluid Recovery System with Primary Fluid Recovery Driven by a Hydrostatic Chamber
[0074] Referring now to FIG. 2 , there is shown a system 10 according to one embodiment of the present invention. System 10 is shown connected to two shaker screens S- 1 and S- 2 . Alternative embodiments include only a single connection to a single screen or more than two connections to more than two screens. These alternatives are within the scope of the invention. The connections to the screens S- 1 and S- 2 are made with vacuum screen attachments 12 a and 12 b which are often referred to in the art as “manifolds” or “vacuum manifolds.” The function of these components is to convey downward vacuum force against the fluid-contaminated drill cuttings on the screens S- 1 and S- 2 , thereby removing the fluid from the cuttings which continue to vibrate on the shaker as they are conveyed off the screens S- 1 and S- 2 . Vacuum screen attachments 12 a and 12 b are connected to respective vacuum conduits 14 a and 14 b which join a common conduit 16 that leads directly to a T-junction connector 18 connected to the bottom of a hydrostatic chamber 20 . In this particular embodiment, the interior sidewall of the hydrostatic chamber 20 is provided with a series of downwardly angled baffles 22 to interrupt the upward flow of fluid under vacuum force. Alternative means for interrupting the upward flow of fluid under vacuum source may be provided in the hydrostatic chamber 20 instead of the baffles 22 and embodiments of the system 10 which incorporate such alternatives are within the scope of the present invention.
[0075] In this particular embodiment, the upper end of the T-junction connector 18 is attached to an opening in the bottom of the hydrostatic chamber 20 and the lower end of the T-junction connector 18 is connected to a short length of conduit which leads to a second T junction connector 24 . This second T-junction connector 24 is in communication with fluid dump port 26 . The upper opening in the second T-junction connector 24 is connected to a vacuum equalization tube 28 which is provided in order to reduce the vacuum force in the immediate vicinity of fluid dump port 26 . It is this reduction in vacuum force near fluid dump port 26 that allows the force of air entering the system 10 through fluid dump port 26 to be overcome when the counteracting force of gravity acting on the hydrostatic head of fluid collecting in the hydrostatic chamber 20 becomes greater than the force of air entering the system 10 under vacuum. When this condition is met, fluid will dump from fluid dump port 26 (as described in more detail hereinbelow). In alternative embodiments, the T-junction connector is attached to the sidewall of the hydrostatic chamber 20 adjacent to the bottom of the hydrostatic chamber 20 instead of the bottom of the hydrostatic chamber 20 .
[0076] In the embodiment of FIG. 2 , the interior of the vacuum equalization tube 28 is connected with the interior of the hydrostatic chamber 20 near the top of the hydrostatic chamber 20 . An additional section 30 of vacuum conduit leads out of the hydrostatic chamber 20 at the top and is routed to the vacuum source which in this particular embodiment is provided by a regenerative fan blower 32 . The skilled person will recognize that alternative vacuum sources may be used and systems include such alternatives are also within the scope of the present invention. The regenerative fan blower 32 of this particular embodiment provides a number of advantages over the vacuum sources used in the prior art, most notably it is less expensive because its power rating is about 10% of the prior art vacuum sources used in conjunction with large fluid recovery tanks such as shown in FIGS. 1A and 1B . For example, in certain embodiments, the system 10 employs a regenerative fan blower 32 which is power rated for 3 HP. In contrast prior art vacuum pump systems (such as the vacuum pump shown in FIG. 1 ) used for similar purposes require power ratings about 10-fold higher (25 to 30 HP). In addition, a regenerative fan blower 32 generally requires maintenance on a significantly less frequent basis than the vacuum pumps currently in use.
[0077] In the embodiment shown in FIG. 2 , an optional fluid trap is provided by a fluid separator 34 whose function is to ensure that fluid does not move further downstream and enter the regenerative fan blower 32 . Examples of fluid separators are produced commercially by companies such as Eaton (www.eaton.com; search query: gas liquid separators). Other alternative embodiments will operate without the presence of the fluid separator 34 and such embodiments are also within the scope of the present invention.
[0078] In certain embodiments, additional optional features are included in the system. These features are also illustrated in FIG. 2 . For example, the fluid separator 34 is provided with an automatic dump port 40 and a level shut-off switch 38 whose function is to disengage the vacuum source (regenerative fan blower 32 in this embodiment) when the level of fluid rises to a pr)-determined level. Dump port 40 is then opened automatically to allow fluid to dump from the system 10 . The fluid separator 34 may also be provided with an upper float valve 42 as a back-up means for disengaging the regenerative fan blower 32 when the fluid level reaches the top portion of the fluid separator 34 . Also shown is a vent valve 44 disposed in vacuum conduit section 28 . Vent valve 44 provides a means for manual control of the vacuum source when operating conditions require an adjustment of vacuum force on the screens S- 1 and S- 2 . For example, if the cuttings become stalled on the screens S 4 and S- 2 , there may be excessive vacuum force on the cuttings which holds them in place on the screens S- 1 and S- 2 and prevents the desired conveyance of the cuttings from the screens S- 1 and S- 2 . In such a case, opening of vent valve 44 to reduce the vacuum force may allow the cuttings to resume conveyance from the screens S- 1 and S- 2 , as desired. Additional safety valves 46 and 48 , an in-line filter 50 and vacuum gauges 52 and 54 are provided in and/or adjacent to vacuum conduit section 33 near the regenerative fan blower 32 to provide additional manual control and to monitor the operation of the system 10 .
[0079] To operate the system 10 , the regenerative fan blower 32 is switched on and a vacuum force is pulled (as indicated by the solid arrows in FIG. 2 ) down through the screens S- 1 and S- 2 , through the vacuum screen attachments 12 a and 12 b, through the vacuum conduits 14 a, 14 b, and 16 , through the hydrostatic chamber 20 , through the vacuum equalization tube 28 , through vacuum conduit section 30 , through the fluid separator 34 and through vacuum conduit section 33 . Additionally, vacuum force is pulled through fluid dump port 26 and vent valve 44 as indicated by solid arrows at these locations. In certain embodiments, the area or diameter opening of fluid dump port 26 is adjustable and can be throttled as a means of adjusting the balance between the force of gravity acting on the hydrostatic head of fluid in the hydrostatic chamber 20 and the influx of air under vacuum into the system 10 through fluid dump port 26 . During a normally functioning process, fluid is conveyed from the cuttings on the screens S- 1 and S- 2 through the first portions of the vacuum force pathway described above. However, most of the fluid does not travel past the hydrostatic chamber 20 because it collects inside the hydrostatic chamber 20 and in the vacuum equalization tube 28 to the point where the growing column of fluid forms a hydrostatic head with pressure sufficient to counteract the influx of air entering the system 10 through fluid dump port 26 . The vacuum equalization tube functions to reduce the vacuum force near fluid dump port 26 . After this balance between the force of inflow of air into dump port 26 under vacuum and the force of gravity acting on the hydrostatic head has been exceeded, fluid will be dumped from fluid dump port 26 until the column of fluid is reduced in height to the point where the force of gravity acting on the column is no longer sufficient to counteract the force of air flowing into the system 10 through fluid dump port 26 . This cycle will repeat for as long as the vacuum is switched on and fluid is pulled through the system 10 .
[0080] Fluid dumped from fluid port 26 is routed to the mud tanks (not shown) as indicated by the broken arrow in FIG. 2 , using a conventional fluid conveyance system. As a result, there is no need for a large fluid holding tank as described above.
[0081] While most fluid being removed from drill cuttings will be dumped from fluid dump port 26 and thereafter conveyed to the mud tanks, the skilled person will appreciate that this mechanism will not be sufficient to remove all fluids, particularly when they exist in the vapor state. It is advantageous in certain embodiments to capture such fluids escaping from the hydrostatic chamber 20 via vacuum conduit section 30 . Therefore, system 10 is provided with a fluid separator 34 . When fluids accumulate in the fluid separator 34 to a pre-determined level, a level shut-off valve is automatically engaged and the regenerative fan blower is then shut off. In certain embodiments, this process is coupled to the opening of valve 40 to dump fluid from the fluid separator 34 .
[0082] Certain alternative embodiments of system 10 are configured to automatically stop and re-start the regenerative fan blower 34 at regular intervals. When the vacuum force is disengaged, the compensating reflexive motion of the screens S- 1 and S- 2 may displace the drill cuttings from the screens S- 1 and S- 2 which may reduce clogging of the screens S- 1 and S- 2 . As a result, this may also reduce the need for rig workers to regularly inspect and clear clogged shaker screens. In certain embodiments, methods of operating the system of the present invention include an automatic shut-off of the regenerative fan blower 34 at intervals ranging from about 10 to about 20 minutes for a period of about 10 to about 20 seconds, after which the regenerative fan blower 34 is re-started.
Example 2
Drill Fluid Recovery System with Primary Fluid Recovery Driven by an Air Distribution and Fluid Dump Assembly and Secondary Fluid Recovery Driven by a Hydrostatic Chamber
[0083] In accordance with another embodiment of the present invention and with reference to FIG. 3 , there is shown another system 100 for recovering drilling fluid from drill cuttings. System 100 has many features similar to the features of the embodiment shown in FIG. 2 and therefore similar reference numerals are used in the ensuing description of operation of this system. The main difference between system 10 ( FIG. 2 ) and system 100 ( FIG. 3 ) is that system 100 is provided with a conduit connector unit which is herein described as the “air distribution and fluid dump assembly.” The air distribution and fluid dump assembly 15 is connected to vacuum conduits 14 a and 14 b and to vacuum conduit 16 which leads to the hydrostatic chamber 20 . It is to be understood that the structure of the air distribution and fluid dump assembly 15 can be modified to include additional ports for additional conduits originating from additional shaker screens. The air distribution and fluid dump assembly 15 is provided with a fluid dump port 17 which faces downward from the main body of the air distribution and fluid dump assembly 15 . Fluid dump port 17 may be provided with a means of adjusting the area or diameter of the port opening.
[0084] Making the opening of dump port 17 smaller will decrease the total force of the air flow entering the system 100 through the opening and vice versa. Therefore, an optimized dump port 17 will allow the force of gravity acting on the weight of the fluid passing over the opening to overcome the in-flow air pressure while allowing the fastest dump rate possible. If the opening is too big, the pressure of the in-flow air will counteract the gravity force acting on the fluid in the air distribution and fluid dump assembly 15 and prevent fluid from dumping. If the opening is too small, fluid will exit but at a slower rate which may not keep the same pace as the rate of fluid entry into air distribution and fluid dump assembly 15 . As a result, most of the fluid will bypass the air distribution and fluid dump assembly 15 and continue toward the hydrostatic chamber 20 .
[0085] During operation of system 100 , fluid is drawn from the drill cuttings on the screens S- 1 and S- 2 as in the operation of system 10 ( FIG. 2 ). However, instead of being conveyed directly to the hydrostatic chamber 20 via vacuum conduit 16 (as in system 10 ), it is routed into the air distribution and fluid dump assembly 15 . When the system 100 is operating as intended with generally consistent vacuum force being applied to the undersides of the screens SC- 1 and SC- 2 and when the fluid dump port 17 has a substantially optimized diameter, fluid will enter the air distribution and fluid dump assembly 15 via vacuum conduits 14 a and 14 b and be consistently dumped out at fluid dump port 17 . As noted above in the discussion of the process of fluid dumping from fluid dump port 26 , to achieve dumping of fluid from fluid dump port 17 the force of gravity acting on the fluid moving through the air distribution and fluid dump assembly 15 above fluid dump port 17 should be greater than the force of air entering the air distribution and fluid dump assembly 15 which is induced by the vacuum force in the system 100 . Therefore, it is advantageous in certain embodiments to provide a means for controlling the area or diameter of the opening of port 17 . As noted above, if the area or diameter of the opening of port 17 is too large, excessive air pressure will enter the air distribution and fluid dump assembly 15 and act against the force of gravity on the weight of the fluid, preventing it from exiting through dump port 17 .
[0086] On the other hand, if the area or diameter of the port 17 is designed or adjusted properly, the pressure exerted by aft flowing into the system via port 17 will be overtaken by the pressure provided by the force of gravity acting on the weight of the fluid above the opening and as a result, fluid will be dumped from port 17 . Therefore, one particular embodiment of the system includes an air distribution and fluid dump assembly with an overall interior volume of about 12 to about 20 cubic inches having three vacuum conduit ports with diameters of about 2 to about 3 inches and a fluid dump port with an opening diameter of about 0.25 to 0.75 inches. This arrangement has been found to produce relatively consistent dumping of fluid through port 17 when a total vacuum force of about 195 to about 235 CFM (cubic feet per minute). This arrangement provides between about 4 to about 6 CFM of air flow through dump port 17 into the system 100 . It is estimated that air enters the system at approximately the same rate through dump port 26 which is responsible for dumping fluid from the hydrostatic chamber 20 as described above. Additionally, about 22 to about 28 CFM of air enters the system 100 via vent valve 44 .
[0087] Without being bound by any particular theory, it is believed that the collision of turbulent streams of fluid entering the air distribution and fluid dump assembly 15 from directionally opposed vacuum conduits 14 a and 14 b may provide the effect of slowing down the vacuum-induced fluid flow above dump port 17 , thereby inducing the fluid to be overtaken by gravity to exit the system at port 17 . Thus, in alternative embodiments employing conduits from three or more screens, it is advantageous to provide an air distribution and fluid dump assembly with opposed vacuum conduits (such as the arrangement shown in FIG. 3 ) to encourage the incidence of collisions of opposing streams of fluid.
[0088] It is estimated that during operation, for example at an air flow rate of about 195 to about 235 CFM, and without significant blockage of the screens by cuttings or other extraneous materials, about 80% of the fluid drawn from cuttings on the screens S- 1 and S- 2 will exit the system 100 at fluid dump port 17 when fluid dump port 17 is provided with an opening having a diameter of about 0.5 inches. The remaining fluid will continue to be conveyed by vacuum conduit 16 into the hydrostatic chamber 20 . The hydrostatic chamber 20 then functions as described above for system 10 , with the exception that fluid is expected to exit from fluid dump port 26 much less frequently than would be observed for system 10 because 80% of the total fluid conveyed from the cuttings has already exited the system at fluid dump port 17 .
[0089] During blockage of the screen S- 1 and/or screen S- 2 , less fluid is drawn into the system from the drill cuttings. As a result, less fluid flows into the air distribution and fluid dump assembly 15 . It follows that the mass of fluid flowing above port 17 is less than it would be during optimal fluid recovery conditions. As a result, the balance between the gravity force on the fluid passing over port 17 and the force of the air intake at port 17 is disrupted and the air intake force prevents the reduced mass of fluid from dumping from port 17 . In such cases, the majority of fluid would then be conveyed to the hydrostatic chamber 20 where it is then dumped more frequently via dump port 26 . The remaining components of system 100 operate in a manner similar to their operation in the previously described operation of system 10 . In such cases where blockages of the screens occurs, the blockages may be automatically resolved by the automatic vacuum shut-off mechanism described above, which may take advantage of the compensating reflexive motion of the screens to catapult cuttings of the screens. The manual valve 44 may also be used for this purpose.
Example 3
Drilling Fluid Recovery System with a Dynamic Fluid Reservoir and Vacuum Control with Fluid Level Sensing
[0090] Referring now to FIG. 4 , there is shown a system 1000 according to another embodiment of the present invention. In FIG. 4 , components common to the previous embodiments are indicated by reference numerals in the 100 series. System 1000 is shown connected to two shaker screens S- 1 and S- 2 in a manner similar to that used in the previously discussed embodiments. Alternative embodiments include only a single connection to a single screen or more than two connections to more than two screens. These alternatives are within the scope of the invention.
[0091] The connections to the screens S- 1 and S- 2 are made with vacuum screen attachments 120 a and 120 b. Vacuum screen attachments 120 a and 120 b are connected to respective vacuum conduits 140 a and 140 b which join a common conduit 160 that leads directly to a fluid reservoir 600 , terminating inside the fluid reservoir 600 in a down-spout 620 which is provided to send drilling fluid down to the bottom of the fluid reservoir 600 . The reservoir has one or more fluid level sensors 660 a and 660 b in communication with a controller 800 . Sensors 660 a and 660 b are triggered when the level of drilling fluid building up inside the fluid reservoir 600 reaches them (unless sensor 660 a is manually or otherwise disabled, sensor 660 b should not be reached by the top surface of fluid collecting in the reservoir. The locations of the sensors 660 a and 660 b along the interior vertical wall of the reservoir 600 are placed for delineation of convenient volumes of drilling fluid. The function of the sensors 660 a and 660 b Will be discussed in more detail hereinbelow when the function of the system is described in detail.
[0092] The reservoir 600 has a fluid dump port 630 at the bottom surface which communicates with a flapper valve 640 for dumping of drilling fluid into a conduit (not shown) for routing it back to the mud tanks where it is re-used in drilling operations. In one embodiment, the flapper valve 640 is a one-way valve having a passive valve flap that, under opening conditions, allows the one-way movement of fluid through the flapper valve.
[0093] A float valve 680 is provided at the top of the reservoir 600 . If the sensors 660 a and 660 b fail. Float valve 680 provides a means for communicating a high fluid level to the controller 800 so that the vacuum can be shut off.
[0094] The reservoir 600 is in-line with the vacuum source (regenerative fan blower 132 ). A vacuum conduit 690 extends from the top of the reservoir 600 and leads to a cyclone vessel 700 whose function is to remove fluid from the air vacuum stream to conserve the filters 740 and 150 . The fluid removed from the vacuum stream is dumped to waste from flapper valve 720 . There is a vacuum gauge 760 upstream of filter 740 .
[0095] The additional components of the system downstream from the cyclone are similar to the components shown in FIGS. 2 and 3 . Additional safety valves 146 and 148 , an in-line filter 150 and vacuum gauges 152 and 154 are provided in and/or adjacent to vacuum conduit section 133 near the regenerative fan blower 132 to provide additional manual control and to monitor the operation of the system 10 .
[0096] During operation, air will be pulled (as shown by the solid arrows) by the regenerative fan blower 132 through the screens S- 1 and S- 2 , through conduits 140 and 160 to the down-spout 620 inside the reservoir 600 . The fluid reservoir is under vacuum pressure while the regenerative fan is running which overcomes the hydrostatic pressure of the fluid and which causes the flapper valve 640 to stay closed. This allows fluid to accumulate in the fluid reservoir 600 until the upper surface of the fluid rises in the reservoir and it reaches sensor 660 a. As the fluid level hits sensor 660 a, sensor 660 a is triggered and sends instructions to the controller 800 (dotted line) to shut off the vacuum source 132 . With the absence of vacuum, there is no force countering the force of gravity acting against the hydrostatic head of fluid in the reservoir 600 and thus the remaining force acts against the flapper valve 640 , causing it to open and allowing the accumulated fluid to dump out of the reservoir.
[0097] The controller 800 includes a timer which is calibrated to provide enough time for the fluid to dump. When the period has elapsed, the controller is programmed to start again and another cycle will begin and end with another fluid dump. In this particular embodiment, sensor 660 a is placed at a height in the reservoir such that the volume of fluid reaching it is 25 L. Sensor 660 b likewise defines a volume of 50 L. If sensor 660 a is manually disabled, the system will dump 50 L on each cycle. Alternative embodiments may be configured to hold and dump different volumes, depending on the requirements for various drilling fluid separations.
[0098] It is advantageous to provide two different dump volumes because different drilling fluids having different densities are used for different drilling operations. It may be advantageous to dump lower density drilling fluid in 50 L volumes and higher density drilling fluid dump in 25 L volumes. Other volumes may be used in alternative embodiments and can be defined by alternative sensor height placement.
Concluding Remarks
[0099] In the description and claims, the terms “upstream” and “downstream” are used as a matter of convenience to identify positions of certain features. The term “downstream” indicates the direction of fluid and gas flow under vacuum source with the last downstream component of the system being the vacuum source. Likewise, the last “upstream” component of the system is the vacuum screen attachment.
[0100] Although the present invention has been described and illustrated with respect to preferred embodiments and preferred uses thereof, it is not to be so limited since modifications and changes can be made therein which are within the full, intended scope of the invention as understood by those skilled in the art.
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A system for recovering used drilling fluid from drill cuttings being processed on a shaker screen. The system includes: a vacuum screen attachment operatively connected to the underside of the shaker screen, the vacuum screen attachment operatively connected to a vacuum source by a vacuum conduit; a hydrostatic chamber located in the vacuum conduit downstream of the vacuum screen attachment, the hydrostatic chamber having a fluid dump port at or adjacent to its bottom surface; a means for setting a limit of fluid accumulation in the hydrostatic chamber, wherein fluid dumps from the fluid dump port when the limit of fluid accumulation is reached; and a conduit for conveying the fluid dumped from the fluid dump port to a storage tank.
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BACKGROUND OF THE INVENTION
The present invention relates to a method and circuit arrangement for determining the partial pressure and the concentration of a gas, termed a measuring gas, which is mixed with at least one additional gas according to the optical absorption method.
In such methods, defined wavelength ranges are alternatingly filtered out of a beam of light of predetermined intensity by means of filters and when the light penetrates a gas to be measured, the intensity of light in a first wavelength range and/or ranges is reduced while that of light in a second wavelength range and/or ranges is not reduced. The intensity of the light radiation is measured with a radiation sensitive detector and fluctuations in output intensity from the light source, variations in the optical transmission and reflection parameters of the beam path, and other interfering values are substantially eliminated from the measurement result by way of comparison of two successive signals having different spectral distributions.
In procedures for optimizing separation nozzle systems, separating experiments operating at low inlet pressures, under small cut and employing low UF 6 concentrations, i.e. very low UF 6 partial pressures, are achieving increasing significance.
The cut θ u of a separation nozzle system which splits an UF 6 stream L into an inner partial stream Li and an outer partial stream Lo is L i /L.
Moreover, it has been found that, for safety reasons, continuous control of the effectiveness of UF 6 low temperature separation is absolutely necessary in the case of separators operating with UF 6 partial pressures below 10 -4 Torr. Additionally, it is desirable, in order to accurately determine the costs for separator systems, to effect continuous measurements of the HF content of the gas being processed.
The known nonselective measuring methods, however, are incapable of providing a precise UF 6 concentration determination at extremely low UF 6 partial pressures because the resulting measuring signal value is determined almost exclusively by the additional gas, which is hydrogen or helium, and which is present in excess amounts. Moreover, the measured value is falsified by gaseous impurity components, e.g. hydrogen fluoride and other compounds contained in commercial UF 6 , which are particularly noticeable at low partial pressures. For these reasons, it is necessary to use selective measuring systems which permit separate measurements of the UF 6 partial pressure and of the partial pressures of the impurity components.
In a known selective process, which is constituted by the photometer process based on the bifrequency principle, the sample contained in a cuvette system is illuminated with light which alternates between two different, but closely adjacent, wavelength ranges, one of the wavelength ranges coinciding with an absorption band of the gas component to be examined and the other wavelength range lying outside of the absorption range so that light therein is not weakened, or attenuated, by the gas. The two wavelength ranges are extracted out of the spectrum of the radiation source by means of gas filters or solid state interference filters. Pulses of light, which alternate between the two wavelength ranges, pass through the cuvette system and are detected by a detector. By comparing every two successive signals produced by light of respectively different wavelengths, fluctuations in the intensity of the light source output or variations in the optical transmission and reflection properties of the beam path are substantially eliminated, as are fluctuations in the sensitivity and the zero point of the detector and variations in background radiation, since they have almost the same effect on successive radiation pulses.
The drawbacks of this process are in particular that for some measuring problems, e.g. in connection with UF 6 analysis, it is necessary to effect complicated dry gas rinsing of optical path outside of the analyzer chamber in order to eliminate e.g. the H 2 O bands, since, on the one hand, the H 2 O spectrum does not have the requisite gap in the region of the ν 3 band of UF 6 and, on the other hand, the light path through air associated with a bifrequency grid analyzer is, in principle, relatively long.
Moreover, the measuring time of the grid analyzer is determined by the time required to switch between the two wavelength ranges required by the bifrequency principle. Due to the high accuracy with which the wavelengths must be selected, the switching frequency is about 10 -2 Hz, so that the measuring times can be no less than about 100 seconds.
In contradistinction to the grid analyzers, quasi-continuous measurements are possible in principle within less than 1 second and over light paths which extend only a short distance through air, if the wavelength selection is effected by means of solid state filters disposed on a filter wheel which rotates, or a pendulum disc which swings, at a comparatively high frequency.
Such measuring problems can also be solved by use of known spectral analyzers with negative gas filtration, in which case gas filters and reference filter cells disposed on a rotating circular disc are moved alternatingly through the beam path.
The drawback of these methods is that they require high chopper frequencies which result in a time overlap between successive signals, producing measuring errors or even making useful measurements impossible.
In known infrared analyzers it has been attempted to avoid this problem by employing a double chopper system. In this case, the very low frequency of the filter chopper, which is lower than the reciprocal of the relaxation period of the thermal detector is used to switch between the two wavelength ranges while additionally the second chopper effects a high frequency interruption of the radiation. However, this arrangement requires a large amount of mechanical components to synchronize the two choppers. Additionally, due to wear of the mechanical components, there will occur temporary changes in synchronization so that long-term stability, which is required for many practical problems, cannot be attained. Furthermore, the signals produced during the switching period of the lower frequency chopper cannot be used for evaluation, i.e. the information furnished by the optical portion of the device is utilized only in part.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to eliminate such a second chopper and to make possible operation with high chopper frequencies which permit continuous measurements of the UF 6 partial pressure and of the UF 6 concentration with response times below one second and simultaneously with a high signal to noise ratio, high sensitivity, and, particularly, at low UF 6 partial pressures.
A more specific object of the invention is to perform measurements in the far infrared range at wavelengths above 4μ so that effective use can be made of UF 6 bands which are heavily absorbing at 16μ, and high zero point stability as well as high reproduceability are assured.
These and other objects are achieved, according to the invention, in a method for determining the partial pressure and concentration of a measuring gas which is in mixture with at least one additional gas according to an optical absorption technique, which method includes producing a beam of light having a predetermined intensity, filtering the beam to alternatingly and cyclically give the light a first spectral distribution in which the light intensity will be reduced by passage through the measuring gas and a second spectral distribution in which the light intensity will not be reduced by passage through the measuring gas, passing the filtered beam through such a mixture, measuring the radiation intensity of the beam after passage through the mixture in a radiation detector having an active element which is heated by the radiation and which produces an output representative of its degree of heating, the output being composed of successive measuring signal segments, resulting from light having the first spectral distribution, alternating with successive reference signal segments, resulting from light having the second spectral distribution, and processing adjacent measuring signal and reference signal segments in order to compensate for fluctuations in the light beam being produced, variations in the light transmission and reflection properties of the beam path and other interference effects, by the improvement wherein the step of processing includes supplying the detector output to an input amplifier having a large signal to noise ratio, and compensating for signal inaccuracies due to superimposition of each signal segment portion produced by heating of the active element on a component representing the cooling behavior which the element would experience after the preceding heating period if further heating did not occur.
According to a first preferred embodiment of the invention, the compensating step is performed by integrating, in an integration member, each measuring signal occurring during a period when the element is being heated by the radiation, which integration is performed with respect to an integration base, applying to the integration member a direct voltage whose value determines the integration base; and adjusting the direct voltage to a magnitude which will cause the integral of a measuring signal, with respect to the integrator base, to have a value of zero when light having the first spectral distribution experiences maximum intensity reduction upon passage through such measuring gas.
The objects according to the invention are further achieved by apparatus for carrying out the above methods and including signal processing means arranged for compensating for signal inaccuracies due to superimposition of each signal segment portion produced by heating of the active element on a component representing the cooling behavior which the element would experience after the preceding heating period if further heating did not occur, composed of an analog computer stage containing an input amplifier having a large signal to noise ratio and connected to receive the detector output; a digital control unit connected for controlling the operation of the computer stage; a first indicator unit connected to the computer stage for providing an indication of the partial pressure of the measuring gas in a container; and a second indicator connected to the computer stage for providing an indication of the concentration of the measuring gas in the container.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic representation of a preferred embodiment of an infrared analyzer according to the invention with rotating gas or solid filters.
FIG. 2a is a waveform diagram illustrating the principle of separation of overlapping output signals from a beam detector which effects halfwave evaluation.
FIG. 2b is a waveform diagram illustrating the principle of separation of overlapping output signals from a beam detector with full wave evaluation.
FIG. 3 is a block diagram of a circuit for effecting analog measuring value processing according to the invention.
FIG. 4 is a block diagram of a circuit for effecting digital measuring value processing according to the invention.
FIG. 5 shows transmission characteristics of sample and reference interference filters.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The basic structure of an infrared analyzer for effecting measurements according to the invention is shown in FIG. 1. The radiation emitted by an infrared radiation source 1 is directed through a first lens system 2 which forms the radiation into an approximately parallel beam, an optical broadband filter 3 which filters out the major portion of the light frequencies not required for the absorption measurements, a measuring cuvette 4 through which the measuring gas flows and whose gas pressure is measured by a pressure gauge 5, and a second lens system 6 which focusses the beam onto a radiation detector 7 which is connected in series with an electronic measuring value processor 8.
Between the first lens system 2 and the broadband filter 3, a filter wheel 9 is disposed in the beam path to act as a chopper. It is driven by a stepping motor 10 and is equipped with gas filters and/or solid interference filters. If gas filters are used, these include a reference filter 11 filled with at least one gaseous component, under high partial pressure, of a gas mixture to be examined and a measuring filter 12 which is evacuated or filled with a gas which does not absorb radiation, such as helium, for example.
In the illustrated position of filter wheel 9, the IR beam 13 penetrates reference filter 11 which is filled with the gases to be measured so that light impinging on detector 7 is reduced by the component absorbed in reference filter 11.
For HF-detection a specific example of the gas filling of reference filter 11 is 1oo Torr HF and 66o Torr He. The broadband filter 3 is selected to be one whose transmission band covers at least one absorption band of the gas to be measured. If measuring filter 12 is introduced into the beam path of the IR beam 13, the light impinging on detector 7 is reduced by the component absorbed by the measuring gas in cuvette 4 since the measuring filter 12 itself permits the beam to pass unattenuated. From the difference in intensity between the two light signals impinging on detector 7 the concentration and the partial pressure of the gas flowing through measuring cuvette 4 can be determined.
The gas mixture in cuvette 4 consists of an H 2 /UF 6 /HF mixture. The components UF 6 and HF are subjected to the concentration and partial pressure determination.
When interference filters constituted by solid bodies are used the transmission curve of the first filter is made to coincide with the absorption band of the gas to be examined, the transmission curve of the second filter is placed as close to that of the first filter as possible, and the broadband filter 3 can be eliminated.
An example of the filter transmission curves for UF 6 measurements is given in FIG. 5.
For precise measurements of the partial pressures and of the concentrations of gas mixtures, the signal to noise ratio of the detector must be made as large as possible, independently of the measuring principle employed. This will occur if the feedback resistance R f or the source impedance R s of the preamplifier associated with the detector is very high since the signal to noise ratio S/R varies according to the relationship:
S/R˜(R.sub.f,s).sup.1/2 (1)
However, there are limits to the values of R f or R s , respectively, since the limit frequency ν g of the amplifier system decreases, with increasing R f and with a system capacitance C, according to the relationship:
ν.sub.g ˜1/(R.sub.f,s.C) (2)
so that there will occur an undesirable overlapping of successive signals in time.
The present invention resolves these conflicting considerations by setting a very high signal to noise ratio by way of a very high feedback resistance R f and/or a very high source impedance R s according to relationship (1) and then electronically eliminating the overlapping of successive signals occurring due to relationship (2). In this way it is possible to realize signal to noise ratios which are higher than was heretofore possible by a factor of 100.
FIG. 2a shows the principle of separating overlapping output signals from a radiation detector 7 for halfwave evaluation. In the selected example, detector 7 is a thermal detector for IR radiation. However, it is just as applicable for every other detector type if there is overlapping of signals. As a result of rotation of filter wheel 9 of the apparatus of FIG. 1, reference signals 20 and measuring signals 21 are generated alternatingly and appear as positive or negative signals with reference to a zero amplitude line 22. The total output signal shown in FIG. 2a is proportional to the time rate of temperature change, dT/dt, of the active element of detector 7, i.e. high positive signal values indicate strong heating, negative signal values correspond to cooling of the detector. The zero amplitude line 22, therefore, corresponds to a steady temperature of the active detector element.
The dashed curve sections 23 and 24 represent the cooling behavior which the detector would experience if the respective next following radiation pulse did not impinge on the detector until after an infinitely long time.
In view of the relationship (2), however, the temperature rise curve of the next radiation pulse is superimposed on curve sections 23, 24. The actual measuring signal from detector 7 is therefore equal to the difference between temperature rise curve 21 and cooling curve 24. For quantitative absorption measurements the integral of this difference function, which is proportional to the radiation intensity, i.e. the area F between curves 21 and 24, is determined.
The area F can be determined by selecting a parallel to the zero line 22 as the integration base 25 and by determining the value of the time integral with reference to this base. The distance 26 of the integration base 25 from the zero line 22 is set on the basis of the requirement that the approximately triangular areas F 1 and F 2 formed essentially by the integration base 25 and curve section 24 be equal in value. Distance 26 may be set, for example, by impressing a direct voltage of selected value on the input of an integration member of the measuring value processor. Advisably, the absolute value of the voltage is then set so that, with a very high pressure in the measuring cuvette 4, the integral of area F becomes zero during the integration interval 27.
This simple measure permits, in addition to decoupling the measuring signals 21 superimposed on reference signals 20, an elimination of undesirable false light, which originates, for example, from the transmission or optical radiation capability of the filters 11 and 12 in a spectral range which cannot be absorbed by the gas under examination. This false light component is automatically compensated with the one-time setting of the direct voltage so that nonlinearities in the indication produced by the analyzer are avoided.
FIG. 2b shows the principle of separation of overlapping output signals from a radiation detector with full wave evaluation of the total signal. Compared to the procedure explained in connection with FIG. 2a, this results in further improvement in the signal to noise ratio.
The integration base 28 for full wave evaluation is located below the output signal 20, 21 from detector 7, the integration limits are fixed by the points of intersection 30, 31, 32, 33, etc. of the output signal 20, 21 with the zero amplitude line 22. For evaluation the following differences are formed: (F 1 '-F 2 ') of the integrals F 1 ', F 2 ' of the reference signal and (F 3 '-F 4 ') of the integrals F 3 ', F 4 ' of the measuring signal. The value which would appear if a very high pressure were present in the measuring cuvette 4 (F 3p ∞ '-F 4p ∞ ') is subtracted from each one of the two differences so as to eliminate any false light influences and compensate for the effect produced by the signal overlapping.
Fip.sub.∞ are the areas that means integration values at infinetly high partial pressure. In practicel pressure is chosen so high that Fip-Fip.sub.∞ <1%.
It is also possible to use the zero amplitude line 22 as the integration base. In that case it is necessary to form the sums of the areas lying above and below the zero amplitude line 22 for the reference signal 20 and for the measuring signal 21.
A block circuit diagram for processing of the measuring values according to the method of the present invention, i.e. for determining the partial pressure and concentration of a measuring gas is shown in FIG. 3.
The measuring value processor 8 of FIG. 1 essentially includes an analog computer stage 40 and a digital control unit 41 which controls the functions of stage 40 and which is arranged together with a mains power portion, a first indicator unit 42 for the partial pressure and a second indicator unit 43 for the concentration, in a 19-inch housing. The output signal from the thermal detector 7 is delivered to a narrowbanded frequency filter 44 and an amplifier 45. The reference signals 20 and measuring signals 21 which appear alternatingly at the output 46 of the amplifier 45 are separately integrated in time succession by integration member 47, the integration values being converted to a logarithmic scale in a function generator 48 having a suitable characteristic. In order to set the spacing 26 or 29 of the integration base 25 or 28 from the zero line 22 to a predetermined value, a predetermined direct voltage is superimposed on the signal 20, 21 appearing at the output 46 of the amplifier 45. This direct voltage is supplied by an adjustable voltage source 64.
The signal supplied to line 49 operates an analog switch connecting 45 and 46 which determines start and stop of integration.
The control unit 41 essentially includes an oscillator with adjustable output frequency which actuates, via a second output 50 and a first frequency divider 51, the current supply for the motor 10 and, via a third output 52 and a second frequency divider 53 with series-connected counter 54, actuates integration member 47 and sets each integration interval to a predetermined value.
The start and stop of integration as shown by FIG. 3 is operated by the control unit 41.
The rotation of filter wheel 9 by motor 10 is monitored by a light barrier 55, the wheel being constructed to act on barrier 55 in a manner to cause the barrier to provide a signal which sets the counter 54 back to zero after each full rotation of the filter wheel 9. The connection between light barrier 55 and control unit 41 is a safety device to ensure that the control unit starts at identical status after each rotation of the chopper.
The function generator 48 is connected in series with an electronic switch 56 which is controlled via a fourth output 57 of the control unit 41 and transfers the direct output voltage associated with the reference signal 20 from unit 48 to a first sample/hold unit 58 and the direct output voltage associated with measuring signal 21 to a second sample/hold unit 59. The output of the first sample/hold unit 58 is connected directly with an adder stage 61, while the output of the second sample/hold unit 59 is connected with the adder stage 61 via an inverter 60, and the adder stage 61 forms a signal proportional to the difference between the two direct voltages. A calibrating member 62 adapts computer stage 40 to the respective gas being measured. Calibrating member 62 consists of an adder to add a constant value at zero partial pressure to make the difference between the outputs of the sample/hold units 58 and 59, zero. A multiplier increases the output signal in order to have calibrated partial pressure indication at the indicator 42.
The output of the adder stage 61 provides a signal representing the partial pressure of the gas being measured and is connected to indicator unit 42, and to the first input of a divider stage 63 which receives at its second input a signal representing the reading on pressure gauge 5 which measures the gas pressure in the measuring cuvette. Divider stage 63 forms a quotient between signal value from amplifier 61, proportional to the partial pressure of the gas component to be measured, and the signal value representing the total pressure of the total mixture in the measuring cuvette, and this quotient, representing the concentration of the gas component to be measured, is displayed by indicator unit 43 which is connected to the output of the divider stage 63.
The electronic signal processor acts as a lock-in amplifier since phase-locked summation of many time successive integrals is effected by the RC members of the sample/hold units 58 and 59, and the chopper frequency coincides with the center frequency of the narrowband amplifier 44, 45. The chopper frequency is equal to the filter wheel rotation rate multiplied by the number of filters on the wheel. An additional increase in the signal to noise ratio is realized by integration over the duration of each of the signal pulses from thermal detector 7. The basic component of control unit 41 is a quarz oscillator the pulses of which are given on programmable counter 54. The output of the counter controls via frequency divider 53, the analog switches of the computer stage to define start/stop operations of the integrator 47. The control unit consists of conventional TTL - and CMOS - integrated circuits respectively.
If the gas mixture contains a plurality of measuring gases and it is desired to monitor several or all of those gases, computer stage 40 can be provided with a plurality of assemblies each operated to monitor a respective measuring gas and each including respective first and second sample and hold units 58 and 59, a respective inverter 60, a respective adder stage 61, a respective calibrating member 62 and a respective divider stage 63.
The block circuit diagram of a digital measuring value processor for practicing the method, i.e. for determining the respective partial pressure and concentration of the measuring gas, is shown in FIG. 4.
In this processor, the analog signals present at the output 69 of the detector 7 are fed to a digital computer stage 70 and, via analog input amplifier 71 therein, to an integrating analog/digital converter 72. The digital integral signals are fed to a digital multichannel memory 74 via a time multiplexer 73. Each channel of memory 74 contains the results of integrations of the reference signal 20 or of the measuring signal 21, respectively, of a gas component to be measured in the gas mixture to be analyzed. Preferably, depending on the manner of computing the integral, the oldest value in each channel of memory 74 is replaced by a new one. In order to improve the signal to noise ratio, the values present in one memory channel are added together in a respective channel of a digital computing unit 75 and are processed further in a digital manner. Instead of an analog addition of a direct voltage present at the output of the preamplifier of the computing stage 70 as described in connection with FIG. 3, the computing unit 75 can add a digital constant automatically as determined once by the computing unit 75 for a very high pressure in the measuring cuvette 4. The entire circuit is monitored by a control unit 76.
In order to further improve the signal to noise ratio, the gain of the input amplifier 71 is automatically and continuously set by an electronically controllable variable resistance 77 so that the digital integrals of the reference signals remain constant in time. The regulation is effected by means of a reference voltage unit 78 and a comparator 79. This regulation can also be used for the analog version. Moreover, the multichannel memory 74 can be employed in the circuit according to FIG. 3 in the form of analog charge coupled device (CCD) memories. The unit 75 consists of a conventional micro processor (Intel 8080). The digital control 76 corresponds to the control unit shown in FIG. 3. The reference Voltage unit 78 and comparator 79 are conventional integrated circuits.
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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For determining the partial pressure and concentration of a measuring gas which is in mixture with at least one additional gas according to an optical absorption technique, in which a beam of light having a predetermined intensity and alternatingly and cyclically having a first spectral distribution in which the light intensity will be reduced by passage through the measuring gas and a second spectral distribution in which the light intensity will not be reduced by passage through the measuring gas, is passed through such a mixture and its radiation intensity after passage through the mixture is measured in a radiation detector having an active element which is heated by the radiation and which produces an output representative of its degree of heating and composed of alternating measuring signal segments, resulting, respectively, from light having the first and the second spectral distribution, and adjacent signals segments are processed in order to compensate for various interference effects, the detector output is delivered to an input amplifier having a large signal to noise ratio, and signal inaccuracies due to superimposition of each signal segment portion produced by heating of the active element on a component representing the cooling behavior which the element would experience after the preceding heating period if further heating did not occur are compensated by integrating, in an integration member, successive portions of the detector output with respect to an integration base which has a fixed value relative to the detector output value corresponding to a constant active element temperature.
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FIELD OF THE INVENTION
[0001] The present invention relates to a shotgun shell magazine, and more particularly, to a shotgun shell magazine configured to be used with an automatic or semi-automatic assault-type firearm. Specifically, the present invention relates to a shotgun shell magazine configured for use with an M-16/AR-15 firearm.
BACKGROUND OF THE INVENTION
[0002] There are a number of automatic and semi-automatic firearms used by military personnel as well as civilians. While fully automatic firearms are generally illegal for use by the civilian population, many of the components which constitute an automatic firearm are the same as those found with legal semi-automatic models. Arguably the most popular semi-automatic assault-type firearm used by civilians, particularly within the United States, is the AR-15. The AR-15 is the semi-automatic variant of the fully automatic M16 firearm used by United States military personnel. (AR-15 is a registered trademark of Colt Industries. A number of additional manufacturers manufacture clones of the AR-15 and market these clones under separate trademarks. While used throughout the specification, it is to be understood that the term AR-15 is meant to include not only those firearms manufactured by Colt Industries, but also those additional clones and any variants thereof).
[0003] The AR-15 and M16 are designed as modular firearms generally comprising a buttstock, lower receiver, upper receiver and barrel assembly. Each component is separable from one another and affords firearm owners the opportunity to customize the firearm with after-market components such as barrels of differing lengths, upper receivers designed to handle different calibers of ammunition, flashlights, hand guards, grenade or flare launchers, flash or sound suppressors, grips, and front or rear sights. To operate, the lower receiver is configured to include a trigger wherein activation of the trigger causes a cartridge housed within the chamber of the upper receiver to be fired out the barrel of the firearm by action of a reciprocating bolt carrier group. Internal mechanisms of the upper receiver expel the shell casing of the fired cartridge from the chamber while components engaged with the magazine housed within the magazine well of the lower receiver feed a new cartridge into the now-empty chamber. The buttstock mounts to the lower receiver and includes a buffer assembly and action (or recoil) spring in communication with the bolt carrier group where the spring pushes the bolt carrier group back toward the chamber in preparation of firing another cartridge.
[0004] To date, most automatic and semi-automatic firearms, like the AR-15, have been configured to fire rifle cartridges. Attempts to modify these firearms, and particularly the AR-15, to fire shotgun shells have run into a number of problems. For instance, AR-15 have been modified to accommodate .410 bore shells but these modifications require lower receivers which no longer satisfy military specifications. Other modifications continue to result in jamming or binding of the shotgun shells when a shell has been fired, is being ejected, or is being extracted from the magazine and loaded within the chamber.
[0005] As such, there is a need for a shotgun shell magazine which is configured to mount within a lower receiver, such as that of an M-16 or AR-15, having a magazine well meeting military specifications. The present invention addresses these and other needs.
BRIEF SUMMARY OF THE INVENTION
[0006] In general, an embodiment the present invention is directed to a shotgun shell magazine for use in a firearm. The magazine is detachably received within a magazine well on the firearm with the firearm configured to strip a shotgun shell from the magazine and load the shotgun shell into a firearm chamber. The magazine comprises a magazine body having an open top end and defines a cavity configured to receive one or more shotgun shells. The magazine body includes a feed lip configured to partially occlude the open top end. The feed lip may have a length between about 10% and about 25% of the total length of the open top end. A follower resides within the cavity and is biased to direct the one or more shotgun shells toward the open top end until a top most shotgun shell engages the feed lip.
[0007] In a further aspect of the present invention, the feed lip has a length of about 20% of the total length of the open top end. The follower may also be biased by a magazine spring where a first end of the magazine spring engages the follower and a second end of the magazine spring engages a floor plate secured to a bottom edge of the magazine body. The follower may also include a magazine stop configured to engage a bolt catch on the firearm after the last of the one or more shotgun shells has been loaded into the firearm chamber.
[0008] In still a further aspect of the present invention, each shotgun shell may have a primer end and an opposing closed end. The follower may also include a ramped upper surface whereby the follower is biased to direct the one or more shotgun shells toward the open top end until the primer end a top most shotgun shell engages the feed lip such that the top most shotgun shell is angled with respect to the open top end and at least a portion of the closed end of the top most shotgun shell lies above a plane created by the open top end of the magazine body.
[0009] In yet a further aspect of the present invention, the magazine body may include a plurality of indicator holes and the follower may include an extended leg wherein the extended leg coincides with an individual indicator hole in the magazine body so as to indicate a number of shotgun shells remaining in the cavity. The extended leg may also include a colored indicator portion configured to be viewed by a user.
[0010] In a further embodiment of the present invention, a shotgun shell magazine for use in a firearm may comprises a magazine body having an open top end and defining a cavity configured to receive one or more shotgun shells. Each shotgun shell may have a primer end and an opposing closed end. The magazine body may also include a feed lip configured to partially occlude the open top end. A follower having a ramped upper surface resides within the cavity and the follower is biased to direct the one or more shotgun shells toward the open top end until the primer end a top most shotgun shell engages the feed lip. In this manner, the top most shotgun shell is angled with respect to the open top end and at least a portion of the closed end of the top most shotgun shell lies above a plane created by the open top end of the magazine body.
[0011] A still further embodiment of the present invention is directed to a shotgun shell magazine for use in an M16/AR-15 military specification (mil-spec) firearm. The magazine is detachably received within a mil-spec magazine well on the M16/AR-15 and the M16/AR-15 is configured to strip a shotgun shell from the magazine and load the shotgun shell into a M16/AR-15 chamber. The magazine comprises a magazine body having an open top end and defining a cavity configured to receive one or more shotgun shells. Each shotgun shell has a primer end and an opposing closed end and the magazine body includes a feed lip configured to partially occlude the open top end. The feed lip may have a length between about 10% and about 25% of the total length of the open top end. A follower having a ramped upper surface resides within the cavity and the follower is biased to direct the one or more shotgun shells toward the open top end until the primer end a top most shotgun shell engages the feed lip. In this manner, the top most shotgun shell is angled with respect to the open top end and at least a portion of the closed end of the top most shotgun shell lies above a plane created by the open top end of the magazine body.
[0012] Additional objects, advantages and novel features of the present invention will be set forth in part in the description which follows, and will in part become apparent to those in the practice of the invention, when considered with the attached figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The accompanying drawings form a part of this specification and are to be read in conjunction therewith, wherein like reference numerals are employed to indicate like parts in the various views, and wherein:
[0014] FIG. 1 is a side view of a representative firearm amenable for use with an embodiment of a shotgun shell magazine in accordance with the present invention;
[0015] FIG. 2 is a cross sectional view of the firearm shown in FIG. 1 ;
[0016] FIG. 3 is a perspective view of an embodiment of a five shell capacity shotgun shell magazine in accordance with the present invention;
[0017] FIG. 4 is a perspective view of an embodiment of a fifteen shell capacity shotgun shell magazine in accordance with the present invention;
[0018] FIG. 5 is a side view of the shotgun shell magazine shown in FIG. 4 ;
[0019] FIG. 6 is a cross section view of the shotgun shell magazine shown in FIG. 5 with fifteen shotgun shells loaded into the magazine;
[0020] FIG. 7 is a cross section view of the shotgun shell magazine shown in FIG. 6 showing the magazine empty of shotgun shells;
[0021] FIG. 8 is a side with of a follower amenable for use within an embodiment of a shotgun shell magazine in accordance with the present invention; and
[0022] FIG. 9 is a perspective view of the follower shown in FIG. 8 .
DETAILED DESCRIPTION OF THE INVENTION
[0023] Referring to the drawings in detail, and specifically to FIGS. 1 and 2 , a firearm, such as the AR-15, is generally indicated by reference numeral 100 . Firearm 100 may be a modular firearm consisting of a number of components and subcomponents. Major components of firearm 100 may include lower receiver assembly 110 , upper receiver assembly 112 , buttstock assembly 114 and barrel assembly 116 . To assemble a completed firearm, upper receiver assembly 112 is coupled to lower receiver assembly 110 while buttstock assembly 114 is connected to the lower receiver assembly 110 and barrel assembly 116 is mounted onto upper receiver assembly 112 . Lower receiver assembly 110 is configured to include a magazine well 118 adapted to slidably receive a magazine 120 therein. Magazine 120 may carry one more cartridges, bullets or shells 122 which may be serially loaded within a chamber 124 in upper receiver assembly 112 . Activation of the firing mechanism (not shown) is controlled by trigger 126 . A grip 128 (such as a pistol grip, as shown) allows the user to aim and control the firearm while placing the user's trigger index finger in close proximity to the trigger. In this manner, the user can aim the firearm to the target and extend the trigger index finger to engage the trigger without losing control or accuracy of the firearm.
[0024] Most assault-type firearms are configured to be operated as rifles and include a rifled barrel and are chambered to receiver and fire rifle cartridges. By way of example, the most ubiquitous civilian assault weapon, the AR-15, is generally chambered for standardized rounds such as the Remington .223 cartridge or the 5.56×45mm NATO military cartridge. As a result, magazines, and more importantly the magazine well configured to receive these magazines, of the AR-15 have been standardized, with such standardization being generally referred to as meeting United States Military Standards or, more commonly as being “mil-spec”. Assault weapons, such as the AR-15, have also been modified to chamber and fire .410 bore shotgun shells. However, these firearms suffer from a number of drawbacks. For instance, 2.5 inch long shotgun shells tend to bind within the chamber and/or magazine thus leading to performance failures. In an attempt to alleviate these binding issues, firearms have been modified such that the magazine well of the lower receiver is slightly larger than the standard AR-15 magazine well such that the larger magazine well can receive a larger magazine such that the shotgun shells can more repeatably be extracted from the magazine and chambered within the upper receiver. This modification, however, renders the lower receiver assembly no longer mil-spec and also leads to difficulties when mating the upper and lower receivers.
[0025] As shown in FIGS. 2-6 , an embodiment of a shotgun shell magazine 120 / 120 ′ of the present invention is configured to reside within the magazine well 118 of a mil-spec AR-15 firearm 100 . Shotgun shell magazine 120 includes a magazine body 130 that may be proportioned so as to define a 5 round magazine (i.e. can receive a maximum of five .410 bore shotgun shells 122 ). See FIG. 3 . However, alternative capacity magazines, such as a 15 round magazine 120 ′ (see FIG. 4 ), may be constructed in accordance with the teachings of the present invention as will be discussed more fully below. It should be understood by those skilled in the art that magazines may be produced which include any desired capacity and that such alternative magazines are to be considered within the teachings of the present invention.
[0026] With reference to FIGS. 4-6 , magazine 120 ′ is generally comprised of a magazine body 130 ′ defining a magazine cavity 132 . Cavity 132 is proportioned to receive one or more shotgun shells 122 . In accordance with one aspect of the present invention, shotgun shells 122 are 2.5 inch long .410 bore shotgun shells filled with either shot or slugs. The portion 134 of magazine body 130 ′ may be slightly narrower than the remainder 136 of magazine body 130 ′ so as to form a step 138 . Portion 134 is proportioned to be removably insertable within magazine well 118 (see FIG. 1 ) while step 138 abuts the lower periphery of magazine well 118 so that magazine 120 ′ is properly loaded within magazine well 118 . To that end, portion 134 may include one more grooves 140 that mate with corresponding ridges (not shown) defined on the internal faces of magazine well 118 to ensure that magazine 120 ′ is mounted within firearm 100 in the proper orientation.
[0027] The top edge 142 of magazine body 130 ′ generally defines an opening to cavity 132 such that shotgun shells 122 may pass out from magazine 120 ′ and into chamber 124 of upper receiver assembly 112 (see FIG. 1 ). To allow controlled, selective extraction of a single shotgun shell 122 , a feed lip portion 144 of top edge 142 is configured to extend around and partially encircle the metal casing 146 at the rim end 148 of the top most shotgun shell 122 . In accordance with an aspect of the present invention, a length 145 of feed lip portion 144 is proportioned to be less than about 25% of the total length 135 of portion 134 of magazine body 130 ′, in more particularly about 20% of the total length 135 . In this manner, shotgun shells 122 may be serially extracted from magazine by the bolt carrier (not shown) within the upper receiver assembly 112 without jamming or binding the shotgun shell 122 within magazine body 130 ′ or chamber 124 as is known with current attempts at providing AR-15 magazines for .410 bore shotgun shells. To that end, magazine body 130 ′ may define a recess 150 configured and positioned such that the bolt carrier can engage metal casing 146 to slide the shotgun shell 122 beyond the feed lip portions 144 . Once shotgun shell 122 clears the obstruction created by feed lip portions 144 , the shotgun shell 122 can then be directed into chamber 124 for eventual firing. To control lateral movement of the plastic hull portion 154 of shotgun shell 122 , top edge 142 may further include upwardly extending guide lips 156 .
[0028] Housed within cavity 132 of magazine body 130 ′ is a follower 160 onto which are loaded one more shotgun shells 122 . Follower 160 is biased upwardly toward top edge 142 by way of a biasing member 162 . Biasing member 162 may be a magazine spring as is known in the art. The opposing end of biasing member 162 may be fastened to a floor plate 164 which in turn is secured to the bottom edge 166 of magazine body 130 ′. Floor plate 164 may be directly fastened to bottom edge 166 or may be constrained within cavity 132 by a magazine base plate 168 which is fastened or physically bonded to bottom edge 166 . Biasing member 162 exerts a spring force against follower 160 such that the top most shotgun shell 122 is constrained within magazine body 130 ′ by feed lip portions 144 as discussed above. Once a shotgun shell has been fired and the next subsequent shotgun shell extracted by the bolt carrier, follower 160 through urging of biasing member 162 advances the immediately next shotgun shell 122 until this next shell engages the feed lip portions. Shotgun shells 122 continue to load within chamber 124 upon repeated firing of the firearm 100 until such time the last shotgun shell is loaded into the chamber.
[0029] Upon loading of the bottom most shotgun shell 122 within chamber 124 , a magazine stop 170 resident within a stop cavity 172 defined within follower 160 may be biased outwardly via a stop biasing member 174 housed within combined bore 176 a, 176 b in follower 160 and stop 170 , respectively (see FIG. 7 ). The outwardly extending magazine stop 170 may then engage the bolt catch (not shown) in the lower receiver to stop the bolt's travel thereby enabling the bolt to be locked to the rear (toward buttstock 114 ). The empty magazine can then be removed from magazine well 118 and a new, loaded magazine may then be inserted. The bolt catch may then be disengaged such that the bolt carrier may strip the top most shotgun shell from the newly loaded magazine. When magazine 120 ′ contains one or more shotgun shells 122 , biasing member 174 is compressed by magazine stop 170 engaging the internal surface of magazine body 130 ′ such that magazine stop rides along the internal surface until such time as the bottom most shotgun shell 122 is loaded within chamber 124 and magazine stop extends outwardly from recess 150 as described above.
[0030] Turning now to FIGS. 8 and 9 , an isolated view of follower 160 is shown. As shown most clearly in FIG. 8 , follower 160 is configured include a ramped upper surface 180 extending at an angle 182 with respect to the plane 183 defined by top face 171 of magazine stop 170 . As seen in FIG. 9 , ramped upper surface 180 may be adapted to include a concave recess 184 . Concave recess 184 may be configured to have a radius equal to or slightly larger than the external circumference of a standard .410 bore shotgun shell 122 . In this manner, shotgun shell 122 should nest within recess 184 such that rolling of shotgun shell 122 on ramped upper surface 180 is reduced, particularly once shotgun shell 122 has disengaged from feed lip portions 144 upon being loaded into chamber 124 as described above. Ramped upper surface 180 of follower 170 , coupled with feed lip portions 144 , causes at least a portion of the closed (i.e. crimped or rolled) end 154 of top most shotgun shell 122 to extend externally from magazine body 130 ′ at an angle 190 with respect to a plane 191 created by feed lip portions 144 while the metal casing 146 engages feed lip portions 144 (see FIG. 5 ). As described above, upwardly extending guide lips 156 of magazine housing 130 ′ aid in preventing lateral movement of the top most shotgun shell 122 . Angling of the top most shotgun shell 122 in such a manner facilitates proper stripping and chambering of the shotgun shell by the bolt carrier during reloading of firearm 100 .
[0031] In accordance with a further aspect of the present invention, follower 160 may include one or more downwardly extending legs 192 a, 192 b. These downwardly extending legs may facilitate placement and compressive loading of magazine biasing member 162 . Magazine body 130 ′ may include a plurality of indicator holes 194 (see FIGS. 4 and 7 ) which are spaced apart from one another such that as follower 160 is biased upwards through subsequent loading of successive shotgun shells as described above, an indicator portion 196 on follower 160 is viewable through the respective indicator hole which corresponds to the number of shotgun shells 122 remaining within magazine 120 ′. In this manner, the firearm user may monitor the number of shells remaining by visually determining where the indicator portion 196 is located along magazine body 130 ′. If follower 160 is fabricated of materials identical to or similar to magazine body 130 ′ such that visually interrogation of the magazine body 130 ′/follower 160 does not readily indicate the number of shells remaining, identifier portion 196 on one or both of legs 192 a, 192 b (such as leg 192 b as shown in FIGS. 8 and 9 ) may be colored so as to be more readily viewable by the firearm user through indicator holes 194 .
[0032] Although the present invention has been described in considerable detail with reference to certain aspects thereof, other versions are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the aspects contained herein.
[0033] All features disclosed in the specification, including the claims, abstract, and drawings, and all the steps in any method or process disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. Each feature disclosed in the specification, including the claims, abstract, and drawings, can be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
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A shotgun shell magazine to be received within a mil-spec magazine of an M16/AR-15 mil-spec firearm is disclosed. The magazine comprises a magazine body having an open top end defining a cavity configured to receive one or more shotgun shells. The magazine body includes a feed lip which partially occludes the open top end and has a length between 10% and 25% of the length of the open top end. A follower having a ramped upper surface resides within the cavity. The follower is biased to direct the shotgun shells toward the open top end until the primer end of a top most shotgun shell engages the feed lip. The top most shotgun shell is angled with respect to the open top end and at least a portion of the closed end of the top most shotgun shell lies above a plane created by the open top end.
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TECHNICAL FIELD
[0001] The present invention is directed to a system and method for actuating an engine valve. More particularly, the present invention is directed to a system and method for actuating the valves in an internal combustion engine.
BACKGROUND
[0002] An internal combustion engine, such as, for example, a diesel, gasoline, or natural gas engine, typically includes a series of intake and exhaust valves. These valves may be actuated, or selectively opened and closed, to control the amount of intake and exhaust gases that flow to and from the combustion chambers of the engine. Typically, the actuation of the engine valves is timed to coincide with the reciprocating movement of a series of pistons. For example, the intake valves associated with a particular combustion chamber may be opened when the respective piston is moving through an intake stroke. The exhaust valves associated with the particular combustion chamber may be opened when the respective piston is moving through an exhaust stroke.
[0003] The combustion process of an internal combustion engine may generate undesirable emissions, such as, for example, white smoke, particulates and oxides of nitrogen (NOx). These emissions are generated when a fuel, such as, for example, diesel, gasoline, or natural gas, is combusted within the combustion chambers of the engine. If no emission reduction systems are in place, the engine will exhaust these undesirable emissions to the environment.
[0004] An engine may include many different types of emission reduction systems to reduce the amount of emissions exhausted to the environment. For example, the engine may include an engine gas recirculation system and/or an aftertreatment system. Unfortunately, while these emission reduction systems may effectively reduce the amount of emissions exhausted to the environment, these systems typically result in a decrease in the efficiency of the engine.
[0005] Efforts are currently being focused on improving engine efficiency to counterbalance the effect of emission reduction systems. One such approach to improving engine efficiency involves adjusting the actuation timing of the engine valves. For example, the actuation timing of the intake and exhaust valves may be modified to implement a variation on the typical diesel or Otto cycle known as the Miller cycle. In a “late intake” type Miller cycle, the intake valves of the engine are held open during a portion of the compression stroke of the piston.
[0006] The engine valves in an internal combustion engine are typically driven by a cam arrangement that is operatively connected to the crankshaft of the engine. The rotation of the crankshaft results in a corresponding rotation of a cam that drives one or more cam followers. The movement of the cam followers results in the actuation of the engine valves. The shape of the cam governs the timing and duration of the valve actuation. As described in U.S. Pat. No. 6,237,551, a “late intake” Miller cycle may be implemented in such a cam arrangement by modifying the shape of the cam to overlap the actuation of the intake valve with the start of the compression stroke of the piston.
[0007] One problem with implementing a Miller cycle in an engine is that the resulting reduced air flow and compression ratio may negatively impact the performance of the engine under certain operating conditions, such as, for example, to create white smoke. In these types of conditions, engine performance may be enhanced by switching the operation of the engine to a convention diesel cycle. This may be accomplished with a variable valve actuation system, such as the system described in U.S. Pat. No. 6,237,551. As described, the variable valve actuation system may include a valve that is operable to selectively enable and disable a Miller cycle. This technique of switching to a conventional diesel cycle, however, removes any engine performance benefit obtained by using a Miller cycle.
SUMMARY OF THE INVENTION
[0008] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
[0009] A method and apparatus for controlling an intake engine valve capable of variable closing timing. A condition indicative of white smoke production is determined. An intake engine valve is closed at a first crank angle for a given engine operating condition when the condition indicative of white smoke production does not exist. The intake valve is closed at a second crank angle for the given engine operating condition when the condition indicative of white smoke production exists. The second crank angle is less than the first crank angle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description, serve to explain the principles of the invention. In the drawings:
[0011] FIG. 1 is a diagrammatic and schematic representation of an engine system in accordance with an exemplary embodiment of the present invention;
[0012] FIG. 2 is a diagrammatic cross-sectional view of an internal combustion engine in accordance with an exemplary embodiment of the present invention;
[0013] FIG. 3 is a diagrammatic cross-sectional view of a cylinder and valve actuation assembly in accordance with an exemplary embodiment of the present invention;
[0014] FIG. 4 is a schematic and diagrammatic representation of a fluid supply system for a fluid actuator for an engine valve in accordance with an exemplary embodiment of the present invention; and
[0015] FIG. 5 is a flow chart according to one embodiment of the invention.
DETAILED DESCRIPTION
[0016] Reference will now be made in detail to exemplary embodiments of the invention, which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
[0017] An exemplary embodiment of an engine system 10 is illustrated in FIG. 1 . Engine system 10 includes an intake air passageway 13 that leads to an engine 20 . One skilled in the art will recognize that engine system 10 may optionally include various components, such as, for example, a turbocharger 12 and an aftercooler 14 , that are disposed in intake air passageway 13 . An exhaust air passageway 15 may lead from engine 20 to turbocharger 12 .
[0018] Engine 20 may be an internal combustion engine as illustrated in FIG. 2 . For the purposes of the present disclosure, engine 20 is depicted and described as a four stroke diesel engine. One skilled in the art will recognize, however, that engine 20 may be any other type of internal combustion engine, such as, for example, a gasoline or natural gas engine.
[0019] As illustrated in FIG. 2 , engine 20 includes an engine block 28 that defines a plurality of cylinders 22 . A piston 24 is slidably disposed within each cylinder 22 . In the illustrated embodiment, engine 20 includes six cylinders 22 and six associated pistons 24 . One skilled in the art will readily recognize that engine 20 may include a greater or lesser number of pistons 24 and that pistons 24 may be disposed in an “in-line” or “V” type configuration.
[0020] As also shown in FIG. 2 , engine 20 includes a crankshaft 27 that is rotatably disposed within engine block 28 . A connecting rod 26 connects each piston 24 to crankshaft 27 . Each piston 24 is coupled to crankshaft 27 so that a sliding motion of piston 24 within the respective cylinder 22 results in a rotation of crankshaft 27 . Similarly, a rotation of crankshaft 27 will cause a sliding motion of piston 24 .
[0021] Engine 20 also includes a cylinder head 30 . Cylinder head 30 defines an intake passageway 41 that leads to at least one intake port 36 for each cylinder 22 . Cylinder head 30 may further define two or more intake ports 36 for each cylinder 22 .
[0022] An intake valve 32 is disposed within each intake port 36 . Intake valve 32 includes a valve element 40 that is configured to selectively block intake port 36 . As described in greater detail below, each intake valve 32 may be actuated to lift valve element 40 to thereby open the respective intake port 36 . The intake valves 32 for each cylinder 22 may be actuated in unison or independently.
[0023] Cylinder head 30 also defines at least one exhaust port 38 for each cylinder 22 . Each exhaust port 38 leads from the respective cylinder 22 to an exhaust passageway 43 . Cylinder head 30 may further define two or more exhaust ports 38 for each cylinder 22 .
[0024] An exhaust valve 34 is disposed within each exhaust port 38 . Exhaust valve 34 includes a valve element 48 that is configured to selectively block exhaust port 38 . As described in greater detail below, each exhaust valve 34 may be actuated to lift valve element 48 to thereby open the respective exhaust port 38 . The exhaust valves 34 for each cylinder 22 may be actuated in unison or independently.
[0025] FIG. 3 illustrates an exemplary embodiment of one cylinder 22 of engine 20 . As shown, cylinder head 30 defines a pair of intake ports 36 connecting intake passageway 41 to cylinder 22 . Each intake port 36 includes a valve seat 50 . One intake valve 32 is disposed within each intake port 36 . Valve element 40 of intake valve 32 is configured to engage valve seat 50 . When intake valve 32 is in a closed position, valve element 40 engages valve seat 50 to close intake port 36 and blocks fluid flow relative to cylinder 22 . When intake valve 32 is lifted from the closed position, intake valve 32 allows a flow of fluid relative to cylinder 22 .
[0026] Similarly, cylinder head 30 may define two or more exhaust ports 38 (only one of which is illustrated in FIG. 2 ) that connect cylinder 22 with exhaust passageway 43 . One exhaust valve 34 is disposed within each exhaust port 38 . A valve element 48 of each exhaust valve 34 is configured to close exhaust port 38 when exhaust valve 34 is in a closed position and block fluid flow relative to cylinder 22 . When exhaust valve 34 is lifted from the closed position, exhaust valve 32 allows a flow of fluid relative to cylinder 22 .
[0027] As also shown in FIG. 2 , a series of valve actuation assemblies 44 are operatively associated with each intake valve 32 and exhaust valve 34 . Each valve actuation assembly 44 is operable to open or “lift” the associated intake valve 32 or exhaust valve 34 . In the following exemplary description, valve actuation assembly 44 is driven by a combination of a cam assembly 52 and a fluid actuator 70 . One skilled in the art will recognize, however, that valve actuation assembly 44 may be driven by through other types of systems, such as, for example, a hydraulic actuation system, an electronic solenoid system, a piezoelectric actuation system, or any other way known to those skilled in the art.
[0028] In the exemplary embodiment of FIG. 3 , valve actuation assembly 44 includes a bridge 54 that is connected to each valve element 40 through a pair of valve stems 46 . A spring 56 may be disposed around each valve stem 46 between cylinder head 30 and bridge 54 . Spring 56 acts to bias both valve elements 40 into engagement with the respective valve seat 50 to thereby close each intake port 36 .
[0029] Valve actuation assembly 44 also includes a rocker arm 64 . Rocker arm 64 is configured to pivot about a pivot 66 . One end 68 of rocker arm 64 is connected to bridge 54 . The opposite end of rocker arm 64 is connected to a cam assembly 52 . In the exemplary embodiment of FIG. 3 , cam assembly 52 includes a cam 60 having a cam lobe and mounted on a cam shaft, a push rod 61 , and a cam follower 62 . One skilled in the art will recognize that cam assembly 52 may have other configurations, such as, for example, where cam 60 acts directly on rocker arm 64 .
[0030] Valve actuation assembly 44 may be driven by cam 60 . Cam 60 is connected to crankshaft 27 so that a rotation of crankshaft 27 induces a corresponding rotation of cam 60 . Cam 60 may be connected to crankshaft 27 through any means readily apparent to one skilled in the art, such as, for example, through a gear reduction assembly (not shown). As one skilled in the art will recognize, a rotation of cam 60 will cause cam follower 62 and associated push rod 61 to periodically reciprocate between an upper and a lower position.
[0031] The reciprocating movement of push rod 61 causes rocker arm 64 to pivot about pivot 66 . When push rod 61 moves in the direction indicated by arrow 58 , rocker arm 64 will pivot and move bridge 54 in the opposite direction. The movement of bridge 54 causes each intake valve 32 to lift and open intake ports 36 . As cam 60 continues to rotate, springs 56 will act on bridge 54 to return each intake valve 32 to the closed position.
[0032] In this manner, the shape and orientation of cam 60 controls the timing of the actuation of intake valves 32 . As one skilled in the art will recognize, cam 60 may be configured to coordinate the actuation of intake valves 32 with the movement of piston 24 . For example, intake valves 32 may be actuated to open intake ports 36 when piston 24 is withdrawing within cylinder 22 to allow air to flow from intake passageway 41 into cylinder 22 .
[0033] A similar valve actuation assembly 44 may be connected to exhaust valves 34 . A second cam (not shown) may be connected to crankshaft 27 to control the actuation timing of exhaust valves 34 . Exhaust valves 34 may be actuated to open exhaust ports 38 when piston 24 is advancing within cylinder 22 to allow exhaust to flow from cylinder 22 into exhaust passageway 43 .
[0034] As shown in FIG. 3 , valve actuation assembly 44 also includes a fluid actuator 70 . Fluid actuator 70 includes an actuator cylinder 72 that defines an actuator chamber 76 . An actuator piston 74 is slidably disposed within actuator cylinder 72 and is connected to an actuator rod 78 . A return spring (not shown) may act on actuator piston 74 to return actuator piston 74 to a home position. Actuator rod 78 is engageable with an end 68 of rocker arm 64 .
[0035] A fluid line 80 is connected to actuator chamber 76 . Pressurized fluid may be directed through fluid line 80 into actuator chamber 76 to move actuator piston 74 within actuator cylinder 72 . Movement of actuator piston 74 causes actuator rod 78 to engage end 68 of rocker arm 64 . Fluid may be introduced to actuator chamber 76 when intake valves 32 are in the open position to move actuator rod 78 into engagement with rocker arm 64 to thereby hold intake valves 32 in the open position. Alternatively, fluid may be introduced to actuator chamber 76 when intake valves 32 are in the closed position to move actuator rod 78 into engagement with rocker arm 64 and pivot rocker arm 64 about pivot 66 to thereby open intake valves 32 .
[0036] As illustrated in FIGS. 2 and 4 , a source of hydraulic fluid 84 is provided to draw fluid from a tank 87 and to supply pressurized fluid to fluid actuator 70 . Source of hydraulic fluid 84 may be part of a lubrication system, such as typically accompanies an internal combustion engine. Such a lubrication system may provide pressurized fluid having a pressure of, for example, less than 700 KPa (100 psi) or, more particularly, between about 210 KPa and 620 KPa (30 psi and 90 psi). Alternatively, the source of hydraulic fluid may be a pump configured to provide fluid at a higher pressure, such as, for example, between about 10 MPa and 35 MPa (1450 psi and 5000 psi).
[0037] A fluid supply system 79 connects source of hydraulic fluid 84 with fluid actuator 70 . In the exemplary embodiment of FIG. 4 , source of hydraulic fluid 84 is connected to a fluid rail 86 through fluid line 85 . A control valve 82 is disposed in fluid line 85 . Control valve 82 may be opened to allow pressurized fluid to flow from source of hydraulic fluid 84 to fluid rail 86 . Control valve 82 may be closed to prevent pressurized fluid from flowing from source of hydraulic fluid 84 to fluid rail 86 .
[0038] As illustrated in FIG. 4 , fluid rail 86 supplies pressurized fluid from source of hydraulic fluid 84 to a series of fluid actuators 70 . Each fluid actuator 70 may be associated with either the intake valves 32 or the exhaust valves 34 of a particular engine cylinder 22 (referring to FIG. 2 ). Fluid lines 80 direct pressurized fluid from fluid rail 86 into the actuator chamber 76 of each fluid actuator 70 .
[0039] A directional control valve 88 may be disposed in each fluid line 80 . Each directional control valve 88 may be opened to allow pressurized fluid to flow between fluid rail 86 and actuator chamber 76 . Each directional control valve 88 may be closed to prevent pressurized fluid from flowing between fluid rail 86 and actuator chamber 76 . Directional control valve 88 may be normally biased into a closed position and actuated to allow fluid to flow through directional control valve 88 . Alternatively, directional control valve 88 may be normally biased into an open position and actuated to prevent fluid from flowing through directional control valve 88 . One skilled in the art will recognize that directional control valve 88 may be any type of controllable valve, such as, for example a two coil latching valve.
[0040] One skilled in the art will recognize that fluid supply system 79 may have a variety of different configurations and include a variety of different components. For example, fluid supply system 79 may include a check valve (not shown) placed in parallel with directional control valve 88 between control valve 82 and fluid actuator 70 . In addition, fluid supply system 79 may include a source of high-pressure fluid. Fluid supply system 79 may also include a snubbing valve to control the rate of fluid flow from fluid actuator 70 and a damping system, which may include an accumulator and a restricted orifice, to prevent pressure oscillations in actuator chamber 76 and fluid line 80 .
[0041] As shown in FIGS. 1 and 2 , engine system 10 includes a controller 100 , such as an engine valve controller. Controller 100 is connected to each valve actuation assembly 44 and to control valve 82 . Controller 100 may include an electronic control module that has a microprocessor and a memory. As is known to those skilled in the art, the memory is connected to the microprocessor and stores an instruction set and variables. Associated with the microprocessor and part of electronic control module are various other known circuits such as, for example, power supply circuitry, signal conditioning circuitry, and solenoid driver circuitry, among others.
[0042] The transmitted signal may result in the selective opening and closing of directional control valve 88 . If directional control valve 88 is a normally closed valve, the transmitted signal may open the valve to allow hydraulic fluid to flow to and/or from fluid actuator 70 . If directional control valve 88 is a normally opened valve, the transmitted signal may close the valve to prevent fluid from flowing to and/or from fluid actuator 70 .
[0043] As illustrated in FIGS. 1-4 , a variety of sensors known to those skilled in the art may be operatively engaged with engine 20 and/or valve actuation assemblies 44 . Each sensor is configured to monitor a particular parameter of the performance of engine 20 or valve actuation assemblies 44 . Some examples of sensors include an intake manifold temperature sensor, an intake manifold pressure sensor, and an engine speed sensor. One skilled in the art may recognize that alternative sensors may be used with engine system 10 to monitor the performance of engine 20 or valve actuation assemblies 44 .
[0044] As also shown in FIG. 1 , at least one engine sensor 18 is operatively connected with engine 20 . Engine sensor 18 may be any type of sensor commonly used to monitor engine performance. For example, engine sensor 18 may be configured to measure one or more of the following: a rotational speed of the engine, a delivered torque of the engine, a temperature of the engine, a pressure within one or more of cylinders 22 , and a rotational angle of crankshaft 27 .
[0045] As further shown in FIG. 1 , at least one intake sensor 16 may be disposed in intake passageway 13 . Intake sensor(s) 16 may be configured to sense the temperature and/or pressure of the intake air and/or the mass flow rate of the intake air. Intake sensor 16 (s) may be any type of sensor readily apparent to one skilled in the art as capable of sensing these types of parameters and may be disposed at any point along intake passageway 13 .
[0046] As further shown in FIG. 1 , a turbocharger sensor 17 may be operatively connected with turbocharger 12 . Turbocharger sensor 17 may be configured to sense the speed of the turbocharger. Turbocharger sensor 17 may also be configured to any other operational parameter of turbocharger 12 .
[0000] Industrial Applicability
[0047] Controller 100 may operate each valve actuation assembly 44 to selectively implement a late intake Miller cycle for each cylinder 22 of engine 20 . Under normal operating conditions, implementation of the late intake Miller cycle will increase the overall efficiency of the engine 20 . Under some operating conditions, such as, for example, when engine 20 is cold, controller 100 may operate engine 20 on a conventional diesel cycle. In other operating condtions, the controller 100 may operate the engine 20 in a normal Miller cycle. Further, when implementing a normal Miller cycle, under operating conditions indicative of white smoke production, such as, for example, a low intake manifold temperature or a low intake manifold pressure, or both, the controller 100 may operate each valve actuation assembly 44 to implement a shortened late intake Miller cycle, as will be described below.
[0048] When engine 20 is operating under a first set of predetermined operating conditions, controller 100 may implement a normal or shortened Miller cycle by selectively actuating fluid actuator 70 to hold intake valve 32 open for a first portion of the compression stroke of piston 24 . This may be accomplished by transmitting a signal to move control valve 82 and directional control valve 88 to the open positions when piston 24 starts an intake stroke. This allows pressurized fluid to flow from source of hydraulic fluid 84 through fluid rail 86 and into actuator chamber 76 . The force of the fluid entering actuator chamber 76 moves actuator piston 74 so that actuator rod 78 follows end 68 of rocker arm 64 as rocker arm 64 pivots to open intake valves 32 . The distance and rate of movement of actuator rod 78 will depend upon the configuration of actuator chamber 76 and fluid supply system 79 . When actuator chamber 76 is filled with fluid and rocker arm 64 returns intake valves 32 from the open position to the closed position, actuator rod 78 will engage end 68 of rocker arm 64 .
[0049] When actuator chamber 76 is filled with fluid, directional control valve 88 may be closed. This prevents fluid from escaping from actuator chamber 76 . As cam 60 continues to rotate and springs 56 urge intake valves 32 towards the closed position, actuator rod 78 will engage end 68 of rocker arm and prevent intake valves 32 from closing. As long as directional control valve 88 remains in the closed position, the trapped fluid in actuator chamber 76 will prevent springs 56 from returning intake valves 32 to the closed position. Thus, fluid actuator 70 will hold intake valves 32 in the open position, independently of the action of cam assembly 52 .
[0050] Controller 100 may close intake valves 32 by opening directional control valve 88 . This allows the pressurized fluid to flow out of actuator chamber 76 . The force of springs 56 forces the fluid from actuator chamber 76 , thereby allowing actuator piston 74 to move within actuator cylinder 72 . This allows rocker arm 64 to pivot so that intake valves 32 are moved to the closed position. A snubbing valve may restrict the rate at which fluid exits actuator chamber 76 to reduce the velocity at which intake valves 32 are closed. This may prevent valve elements 40 from being damaged when closing intake ports 36 .
[0051] When the engine operating conditions indicate that white smoke production is likely to exist, controller 100 may implement a shortened late intake Miller cycle by selectively actuating fluid actuator 70 to hold intake valve 32 open for a second portion of the compression stroke of piston 24 , the second portion being less than the first portion. That is, the controller 100 closes the intake valve 32 earlier, e.g., at a lower crank angle, than it would have under the non-shortened late intake Miller cycle. Typically this crank angle will still be greater than the crank angle at which the intake valve 32 closes during a conventional diesel cycle.
[0052] FIG. 5 is a flow chart 120 showing one technique for controlling an engine valve 32 according to one embodiment of the invention. In block 122 , the controller 100 determines various engine operating characteristics/conditions. For example, the controller may determine the intake manifold pressure, intake manifold temperature, and engine speed, by ways known to those skilled in the art. Other engine characteristics/conditions known to those skilled in the art could also be determined.
[0053] In block 124 , the controller determines whether the determined engine characteristics indicate that white smoke conditions are likely to exist. For example, a low intake manifold pressure, a low intake manifold temperature, and an excessive amount of fuel (e.g., more than needed for stoichiometric combustion) are all conditions that are more likely to produce white smoke from the engine 20 . Other engine characteristics, or combinations thereof, known to those skilled in the art could also be used.
[0054] If the controller 100 determines that white smoke conditions are not likely to exist, control passes to block 126 . In block 126 , the controller 100 closes the intake engine valve 32 at the conventional Miller cycle crank angle.
[0055] If the controller 100 determines that white smoke conditions are likely to exist, control passes to block 128 . In block 128 , the controller 100 closes the intake engine valve 32 at a shortened Miller cycle crank angle, e.g., sooner than the crank angle at which a conventional Miller cycle would close the intake engine valve 32 .
[0056] FIG. 6 is a graph 130 of intake valve position vs. crank angle according to one embodiment of the invention. At the beginning of the combustion cycle (intake stroke) the intake valve opens (point A). If the controller 100 determines that the engine 20 should be operated in a conventional diesel cycle, the position of the intake valve 32 follows the curve profile 132 shown and closes at point B. If the controller 100 determines that the engine 20 should be operated in a conventional Miller cycle, the position of the intake valve 32 follows the curve profile shown and closes at point C. If the controller 100 determines that the engine 20 should be operated in a Miller cycle, but white smoke conditions are likely to exist, the position of the intake valve 32 follows the curve profile shown and closes at point D.
[0057] For a conventional diesel cycle, the intake valve 32 may close at a crank angle of approximately 160° before top dead center (“BTDC”). For a normal Miller cycle, the intake valve 32 may close at some crank angle greater than approximately 160° before top dead center (“BTDC”). For a shortened Miller cycle, the intake valve 32 may close at a crank angle anywhere between the crank angle for a conventional diesel cycle and a normal Miller cycle.
[0058] The particular crank angle for a shortened Miller cycle may be a function of various engine-operating conditions. In particular, experimentation has shown that the engine speed may be a pertinent factor in determining this crank angle. The exact relationship between engine speed and the crank angle for closure of the intake valve 32 may vary depending on the particular characteristics of the engine design, and may be determined through experimentation.
[0059] Thus, according to one embodiment of the invention, an engine 20 may operate in a normal Miller cycle when conditions of the engine do not indicate that white smoke production is likely, and may operate in a shortened Miller cycle when conditions indicate that white smoke production is likely. Because in a normal Miller cycle the intake valve 32 closes after bottom dead center (“ABDC”), the quantity of air in the cylinders 22 is less than that if the engine 20 was operating in a conventional diesel cycle (where the intake valve 32 closes closer to or at bottom dead center. By closing the intake valve 32 earlier in the shortened Miller cycle, more air is present in the cylinder 22 , leading to a higher pressure and temperature within the cylinder 22 during the combustion cycle. This, in turn, may tend to reduce the production of white smoke.
[0060] Although some examples herein describe an engine 20 capable of operating in a conventional diesel cycle, a normal Miller cycle, and a shortened Miller cycle, the invention may have application to engines that operate only in the normal Miller cycle, to thereby switch between the normal and shortened Miller cycle as conditions indicate.
[0061] It will be apparent to those skilled in the art that various modifications and variations can be made in the engine valve actuation system and method of the present invention without departing from the scope or spirit of the invention. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being limited only by the following claims and their equivalents.
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The present invention provides a method and apparatus for controlling an intake engine valve capable of variable closing timing. A condition indicative of white smoke production is determined. An intake engine valve is closed at a first crank angle for a given engine operating condition when the condition indicative of white smoke production does not exist. The intake valve is closed at a second crank angle for the given engine operating condition when the condition indicative of white smoke production exists. The second crank angle is less than the first crank angle.
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The present invention relates generally to calcining kilns for burning limestone or similar raw materials and more particularly to the structure of the kiln wall for a kiln which includes at least one burner arranged at a distance from the wall of the kiln.
Kilns of the type to which the present invention relates have been fired with gaseous and liquid fuel. Additionally, solid fuels, such as coal dust, have also been used. A kiln of this type may, for example, be a rotary kiln or a shaft kiln. The uniflow regenerative shaft kiln which operates in accordance with the regenerative method is also known and heat consumption of such a kiln has been found to be particularly advantageous. This shaft kiln may be heated with gaseous or liquid fuels. Here again, solid fuels, such as pulverized coal, may also be used with the fuel being fed into the material to be calcined by means of burner openings which are located at the end of a preheating zone of the kiln or at the beginning of a combustion zone of the kiln. In such an arrangement, combustion air flows unidirectionally from the top to the bottom in the charge and reaches a preheating temperature of approximately 700° C.
In such kilns, one or several burner openings can be provided which are formed at the end portions of fuel lances or tubes which are suspended in the charge and through which the fuel feed occurs.
Solid fuels such as pulverised coal contain varying amounts of ash content. Some types of coal, such as brown coal, have an ash content which is approximately only about 4 percent. On the other hand, bituminous coals or anthracite may contain up to 22 percent ash. Additionally, the chemical composition and the melting point of the ashes may vary significantly.
For example, the ash of lignite having high volatile components exceeding 35 percent may have a basic composition, while the ash of most other coals may be acid. The melting point of the ash may fluctuate between 1100° and 1500° C.
The burner openings of the fuel lances must be arranged at a distance from the kiln wall such that the limestone which is located near the kiln wall will become adequately calcined. If there are utilized fuels with high calorific value which are burned with air having been preheated to approximately 700° C., very high flame temperatures will result. This is clearly desirable when using liquid or gaseous fuels due to the fact that at the beginning of the combustion zone of a uniflow regenerative lime shaft kiln, the heat requirement for burning of the limestone is very high. In such cases, a suitable refractory material may be selected for lining of the kiln walls which will not be damaged by the high temperatures of the combustion gases.
If the calcining kiln is to be fired with pulverised coal which contains ash, melted ash may deposit on the refractory walls, particularly if the ash has a low melting point. These deposits tend to increase rapidly over a period of time and controlled kiln operation and the production of good quality lime may become impossible.
Thus, the present invention is directed toward the development of a calcining kiln of the type described wherein the formation of interfering deposits on the kiln walls will be reliably prevented, but is not limited to a regenerative lime kiln.
SUMMARY OF THE INVENTION
Briefly, the present invention may be defined as an improvement in the wall structure of a calcining kiln for burning limestone or similar mineral raw materials having wall means of refractory material and burner means including at least one burner having a burner opening arranged within the kiln at a distance from the kiln wall means. The improvement comprises that in the region below the burner opening, the wall means is constructed to be gas-permeable and that a compressed gaseous medium is supplied through the gas-permeable wall means toward the interior of the kiln.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.
DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a vertical sectional view showing part of a kiln in the end region of the preheating zone and in the beginning of the combustion zone wherein the wall means are structured in accordance with the present invention;
FIG. 2 is a sectional view taken along the line II--II of FIG. 1;
FIG. 3 is a top view showing a part of the brickwork of the kiln of FIG. 1; and
FIG. 4 is an enlarged side view depicting the inside of the wall of the kiln.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, the present invention will be described in connection with a shaft kiln wherein the feed of the fuel, e.g., pulverised coal, occurs by means of fuel lances which are suspended in the kiln shaft.
As indicated in FIG. 1, there is depicted one of the fuel lances 3 through which fuel may be supplied to the furnace. The fuel lance 3 defines at the lower end thereof a fuel opening 4. The location of the fuel opening 4 defines the partition between a preheating zone V and a combustion zone B of the furnace. Thus, the end of the preheating zone V and the beginning of the combustion zone B will be found located at the level of the fuel opening 4 of the lance 3.
The fuel lance 3 is arranged a distance from a wall structure 1 of the furnace. The wall structure 1 may be constructed in different ways and in the region of the preheating zone V, the wall structure 1 includes an inner wall section 5 which consists of refractory bricks such as, for example, fire clay, which are followed on the exterior side thereof by refractory plates 6. On the exterior side of the plates 6 there are provided an additional refractory layer 7 and an insulation layer 8 which is surrounded by a steel shell 9. In the combustion zone B, the wall structure 1 consists of refractory bricks 10, e.g., magnesite bricks, which are adjoined by the refractory plates 6, the insulation layer 8, and the steel shell 9.
As will be evident from FIG. 1, in a region beginning at the end of the preheating zone V and ending at the beginning of the combustion zone B, a wall structure 2 is provided which is constructed to be gas-permeable. As shown in an enlarged scale in FIGS. 3 and 4, the bricks 10 are provided on both lateral surfaces thereof with grooves 11 which extend over the width of the wall structure. A compressed gas, e.g., compressed air, is provided into the interior of the furnace shaft through the grooves 11 in the bricks 10. Thus, over the length of the height of the bricks provided with the grooves 11, a screen or veil of cooling gas is formed which will reliably prevent adherence of melted ash to the interior of the wall.
The wall structure 2 has on the outer side thereof a steel shell 12 which is arranged to form around the outer side of the wall structure an annular gap 13. The compressed medium, e.g., compressed air, is introduced into the annular gap 13 by means of sockets or inlet tubes 14 and the compressed air flows through the grooves 11 in the bricks 10 into the interior of the furnace shaft.
Instead of the bricks 10 provided with the grooves 11, the wall structure 2 may be formed to consist of refractory bricks which have a greater number of pores or capillary openings. In this case, it is not necessary to install the grooves at the lateral walls becaused the compressed medium may penetrate through the pores or capillary openings into the interior of the furnace shaft and thereby prevent in a similar manner the adherence of the melted ash.
As will be evident from FIG. 2, the furnace shaft is formed with a circular cross-sectional configuration having a shaft axis 15. The steel shell 12 which forms the annular gap in the wall structure 2 is held in place by means of supports 16 located a desired distance from the bricks 10 with the outer steel shell 9 being supported by means of supports 17 at the inner steel shell 12.
The gas-permeable wall structure described above may also be applied in also calcining furnaces such as, for example, revolving tubular furnaces.
While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.
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A calcining kiln for burning limestone or similar mineral raw material is formed with a wall structure which is gas-permeable at least in a region adjacent the openings of burners extending to the interior of the kiln with a compressed gaseous medium being supplied through the gas-permeable wall structure toward the interior of the kiln.
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TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates to a solution to improve the security of interactions between a server and a client in client-server applications. Particularly, the invention relates to the control of the whole lifecycle of data traffic between a client and a server applying also internal data flow system within the server only for editable data.
BACKGROUND OF THE INVENTION
[0002] In many kind of applications is necessary the information exchange between the client and the server side of the application, using usually some of the following security features:
Authentication with a user name and its associated password or a digital certificate, Cyphering the communication between the server and the client, using the protocol Secure Sockets Layer (SSL),
[0005] However, even when the authentication process and the SSL (secure communications) are used, or even when the application source code is signed, it does not guaranty the integrity of the information that the client sends to the server. In other words, the client side it's the owner of the machine used by the client and it's possible the manipulation of the information existing in that machine (within memory, within files, etc.).
[0006] For example, in a web application, the client uses the web application or page to make a web request, with said application the client can modify the web request changing the contract between the server and the client, said modifications could be for example:
Modifying received parameters of the web page received from the server. Adding new parameters in the web page. Modifying the uniform resource locators (URL) of the web page received from the server. Adding new URL to the web page received from the server (Performing requests on URL not received from the server). Modifying or adding cookies to the request. Modifying or Adding headers in the web page.
[0013] In other words, the HTTP protocol allows making modifications at the client side so as modify all the data which are sent to the server, changing the original contract (GUI or API interactions) provided by the server. In addition, the client can try different type of attacks using legal input text fields, such as textbox fields within a form.
[0014] For this reason, the requests received in the server must be validated because the reliability and the integrity of the received data are not always guaranteed.
[0015] A solution provided in the state of the art is performing manual validations by software developers with the purpose of avoiding said vulnerabilities. The problem of this solution is not efficient and depends on the human factor; it would desirable an efficient and automatic solution.
[0016] Another solution comprises installing an application firewall performing the validation process automatically; one example of these types of solutions is the application firewall Appshield created in 1999. This firewall is a hardware solution (an appliance) located between the client and the server and processes all the requests from the client and all the responses from the server. The firewall parses all the responses and generates a cyphered text for each link and form. When the client request reaches the firewall, the application verifies whether the request is matches the data generated at the server. The problem is that the parsing process of server responses is not efficient and it would be desirable to have an efficient method to validate all the requests from the client. At the same time this kind of solutions are not easily integrable within development environments, since an additional hardware element is necessary in order to run the solutions. In consequence, is common to find integration problems when the application is deployed within production environments where the application firewall is present.
[0017] U.S. Pat. No. 8,510,827B1 relates to a method for taint tracking for security mechanism. The method “taints” the sensible information in terms of security, i.e. information that cannot be trusted and can modify the normal performance of the operating system. This method is oriented to the field of operating systems and virtualization systems. Therefore this method does not solve the lack of security in web services.
[0018] In the state of the art HDIV open-source project (hdiv.org) improves the performance offered by application firewalls because HDIV does not need to parse the response of web applications, reading all the information from memory within the applications. In other words, HDIV extends the behaviour of some web frameworks (Struts 1, Struts 2, JSF, Spring MVC, Grails) controlling the information flow of the data. On the other hand, HDIV does not implement some of the functionalities implemented by the firewalls, such as stopping DOS attacks or networks attacks. At the same time, HDIV may apply blacklist and whitelist validation patterns against editable data, but does not offer a solution to detect vulnerabilities within source code to avoid risks related with editable data such as SQL injection or XSS web risks.
[0019] The technical problem which is found in the state of the art is how to overcome the risks of the manipulation of applications from client side, preferably in HTTP, in an automatically and efficient way avoiding the need of modifying the source code of applications.
[0020] Although some of the state of the art solutions try to control the data flow between the server and the client, existing solutions are not optimum in the implementation strategy, as it is explained herein below.
[0021] Existing information flow control systems between server and client based on application firewalls, which in the present description is referred to as external implementation strategy, generate an excessive overload or performance overhead since the parsing is carried out on the HTML code coming from the server. At the same time existing JVM (Java Virtual Machine) internal data flow control systems based on compiled code transformation technique, in some cases known as instrumentation, such as HP Fortify or Contrast security products, monitors and control all the input data coming from web browsers at client's side, generating an extra work due to the monitoring of the whole set of received data.
[0022] There is a need for a more efficient data flow control system controlling and understanding the information generated originally at the server.
STATEMENT OF THE INVENTION
[0023] The present invention provides a solution for the aforementioned problem by a method for detection of manipulation of data by a client that performs a request to a server according to claim 1 , a system according to claim 9 and an application according to claim 13 . The dependent claims define preferred embodiments of the invention. All the features described in this specification (including the claims, description and drawings) and/or all the steps of the described method can be combined in any combination, with the exception of combinations of such mutually exclusive features and/or steps.
[0024] In a first aspect of the invention there is provided a method for detection of manipulation of data by a client that performs a request to a server and detection of vulnerabilities within source code, implemented on a system that comprises:
at least one client adapted to
running requests to a server, comprising editable data and non-editable data, preferably editable data from text boxes or HTTP headers, preferably said requests are represented by data receiving responses comprising editable and non-editable data from the server, preferably over the Hypertext Transfer Protocol (HTTP),
at least a server adapted to
receiving said request from the client, and sending said responses to the client,
where the method comprises the following steps:
a. receiving, by either the server or an external entity, such as a firewall, a request from a client, if the request is an initial request go to step c), b. if the request is a non-initial request,
reading, by either the server or an external entity, such as a firewall, the request identifier from the received request, detecting manipulation, by either the server or an external entity, such as a firewall, and finishing the method if the request identifier (STATE_ID) is different to the request identifier (STATE_ID) of a previous request that has been added to a data structure (STATE) created for each risk point of a response of a previous request in the same session, wherein a risk point is preferably predetermined resources or link or form, preferably comprising parameters, detecting manipulation, by either the server or an external entity, such as a firewall, and finishing the method if the content received in the request is different to the content of the data structure (STATE) corresponding to the received request identifier (STATE_ID), detecting manipulation, by either the server or an external entity, such as a firewall, and finishing the method if there is some additional parameter not included within an existing STATE, if the request comprises at least an editable parameter which has been edited or completed by the client, storing by the server the representation of the data comprised in these fields on the server in a second type of data structure (TaintedObjects),
c. generating the response by the server, preferably a HTML page, d. analysing, by server, if during the generation of the response, at least one risk point is generated, preferably URLs or link or forms, e. if there is at least one risk point in the response,
creating, by the server, a data structure (STATE) for each risk point, preferably resources, URLs or link or forms, creating and associating, by the server, a request identifier (STATE_ID) to the data structure (STATE), if the risk point comprises at least one parameter, identifying the typology, editable or non-editable, of the at least one parameter of the risk point, preferably the non-editable typology comprises one of a check box, radio button, select and editable typology comprises one of an editable field textbox or text area,
f. performing a predetermined action if the request comprises at least one editable parameter comprising content which is used during the generation of the response by the server, preferably in SQL queries or output writes improperly programmed known as sink point and sending, from the server, the response to the client or to an external entity, g. receiving the response susceptible to be modified, by the client, h. continuing in step a) if the client sends another request to the server in a same session, preferably using one of the request identifiers (STATE_ID) generated in the step e) of the current request, or a previous request inside the same session.
[0047] The method defined in the present description is considered as a global information flow control method, since, applied on a system comprising a server and a client, the data are controlled ever since data, for example web pages, are rendered at the server and until said data are received back at the server side from a new request from the client. The global information flow control method is defined in the present invention and is carried out by implementing steps “a” to “g” referred to above.
[0048] The firewalls are referred to, in the present description, as application firewall or web firewall in a wide sense, being suitable for any kind of application level protocol (7 th OSI layer), preferably HTTP protocol.
[0049] Said method is carried out applying at least one of known techniques adding an additional behaviour to a server or firewall, said behaviour being used for controlling the data flow globally within applications running on servers, but without amending original source code of said applications. These known techniques are:
Compiled code transformation: this technique can be applied on runtime or in build process of the applications. Specifically the compiled product (for instance .class file in Java EE platform or .il files in .NET platform) is transformed to add the extra behaviour. In the build process transformation, the compiled code is transformed before the deployment of the application into the server. In other words, the deployment product (in Java environments .war, or .ear files) is already transformed before the deployment into the server. In the runtime case, the transformation is implemented when the compiled code is loaded in the memory of the server by the server. One implementation strategy for runtime transformation in Java environments is implementing through Java Instrumentation API. APIs extension: this technique replaces the default implementation of an API or Interface used by an application running on a server (for instance Java, .NET, PHP platforms APIs, utilities libraries APIs, etc.) by other implementation provided by the invention. In order to change the implementation it is necessary to update the configuration files of the application, preferable XML files, but it is not necessary to update source code files of the application. Additional code: especially in web environments such as (PHP, Java EE, .net) it is possible to add additional code that is executed before a request from a client is processed by a server application. This additional code or software component is known as “web filters” and allows adding an extra behaviour in a web request processing process without updating or amending the source code of the applications. An example of this software component is javax.servlet.filter. The web filter is applied within the application running on the server. In other non web environments this kind of extra behaviour may be applied using aspects (Aspect Oriented Programming) or similar software components.
[0053] The risk points are referred to, in the present description, as the whole information contained in a link or form, as well as in other objects, such as resources, URL, parameters names, parameters values, and the like. Risk points may comprise editable or non-editable parameters. For example, risk points of the type “form”, may comprise editable parameters.
[0054] The method according to the invention is carried out starting from step “a” for an initial request. The server generates the response data which is requested by the client. When processing the request, the server can “find” a risk point.
[0055] At the request processing phase, for every risk point, both comprising editable parameters and non-editable parameters, a type of data structure is created, which in the present description is referred to as “STATE”. A STATE comprises:
A string type variable for storing resources or identifiers, or preferably URL, A string type variable for storing the state identifier, or also referred to as STATE_ID, A map for storing parameter's names (the key of the map), and the values of the parameters (the value of the key within the map). The values are represented as an array. A map for storing the types of parameters such as textbox, checkbox, radio button, text area, hidden, select (the key is the parameter name and the value the type of parameter).
[0060] A STATE allows storing the content of the risk points and storing identifiers, in the present description referred to as STATE_ID, representing identification for each risk point. For a link, the STATE specifically may comprise the URL and parameter's names and values. For a form, a STATE may comprise: URL, parameter types, parameters names and parameters values.
[0061] The following step is: sending the initial data requested to the client.
[0062] For every request from the client the step referred to as “validation” is carried out. This is defined, in the steps of a method according to the invention in step “b” wherein validation comprises detecting manipulation if one of the options defined is verified; for this tasks, a comparison between the content of the STATE comprising the identifier (STATE_ID) and the content of the STATE corresponding to the incoming identifier (STATE_ID) is performed. In the case of the non-editable parameters or non-editable data, the comparison or validation is used in a manner such that the content the server sends to the client is stored and compared with the content of the corresponding object or field in the following request the client performs in a same session. This mechanism allows detecting a manipulation if a change in the content is noticed. Validation can be performed either in the server or in an external entity, such as an application firewall. In the last case, the STATE may be sent towards the firewall in the response from the server. Advantageously including the STATEs in a response allows having a better response time in the case where a firewall is used, since the tasks of structuring the data into data objects such as a STATE by the server allows the firewall to save time in parsing the response from the server, and thus only validating the information or data comprised in the STATE.
[0063] If the client sends a new request (non-initial) within the same session to the server, the step “b” is carried out.
[0064] In the present invention, if editable parameters or editable data are detected within the incoming request, step “b” comprises creating a second type of data structure, referred to as TaintedObject(s). TaintedObjects are adapted, at the receiving phase, to store the received parameter's value of the type “editable”, preferably being editable text boxes or text areas. TaintedObjects are characterised in that they comprise an array for pointers pointing at a memory location, where the value, name and identifier of the editable data are stored, wherein memory is understood as internal or external memory or a combination of both.
[0065] TaintedObjects allow storing the content coming from editable data included within the request. The typology of the pointers or objects stored in this data structure are preferably text types; for example within Java programming language, String, StringBuffer, StringBuilder, CharArray.
[0066] As a way of explaining example, for a non-initial request, for step “a” if the user sends a POST request including five parameters and one of them comes from editable data (param1), then in step “b” the TaintedObjects structure is created which comprises said object:
[0000] TaintedObjects={param1},
[0000] where param1 in an embodiment is accountNumber.
[0067] If any new TaintedObject is created or derived from the above TaintedObject list, it is included within this list. For example, if the server creates a new String from a previous tainted string, the “newString” is included within the previous list of parameters, as the example below:
[0000] String SQL=“select . . . ”+accountNumber;
[0000] TaintedObjects={accountNumber, SQL}
[0068] The above explained technique is referred to, in the present description, as propagation.
[0069] In the state of the art, all the information coming from the client is treated as TaintedObjects in the examples above explained. In the present invention, this technique is applied only in the editable parameters or editable objects or data stored in TaintedObjects and the objects derived from said TaintedObjects. This is possible in the present invention due to a global information flow control method.
[0070] In the case that no manipulation is detected, but a TaintedObject is used in some sink point during request processing, the method allows performing a predetermined action, which in a particular embodiment is to create an alert reporting, in an embodiment, the file and line number of the sink point in case this is in the form of programming code, or aborting the loading of the data, or performing proactive actions, preferably escape the string or executing secure functions.
[0071] By applying the use of TaintedObjects to editable parameters or data, which is equivalent in the present invention to apply monitoring of data only on editable data, advantageously the efficiency is increased since the technique, in comparison to the state of the art, is not applied to the whole set of received data.
[0072] Therefore, advantageously this method:
avoids the lack security of the when a communication between a server and a client is susceptible of being modified, the method extracts the necessary information to identify automatically and efficiently the risk points, both editable and non-editable data, of a request sent by the client to a server, and increases the efficiency of the data flow control method at the server, by monitoring the data coming only from editable parameters comprised in forms.
[0075] The method guarantees the integrity of the received request automatically and efficiently.
[0076] In an embodiment of a method according to the invention, if the request is received by an external entity ( 73 ), then the method further comprises
before step c, a previous step of forwarding the request to the server, further, for each non-initial request from the client, forwarding by the external entity towards the server the editable parameters from the first type of data structure (STATE), in step f): sending, from the server to the external entity ( 73 ) all the data structures (STATE) created for the request along with the response, after step f): a following step of
forwarding, by the external entity ( 73 ), the response to the client and storing, by the external entity ( 73 ), the STATES in the external entity ( 73 ).
[0083] Further, for each non-initial request from the client, forwarding by the external entity towards the server the editable parameters from the first type of data structure (STATE). This is performed in order to taint, by the server, the data coming from editable parameters or fields. In the case where the STATE does not comprise editable parameters, this is not performed.
[0084] In another embodiment of the method according the first aspect the STATES are organized, by the server, in a third type of data structure (SCREEN) and if the request is received by an external entity, then the STATES are sent to the external entity, in step f), organized in SCREENs so that the external entity stores the STATES in SCREENs.
[0085] In another embodiment of the method according the first aspect, in the step for storing all STATE generated for each risk point in a SCREEN, can be performed either
in the internal memory of a server, or shared among the internal memory in the server plus one or more complementary servers, or in memory of an external entity.
[0089] Due to the screen data structure the STATES related with previous data, for example web pages or native screens within and Android native app viewed by a user in the same session, can be managed and stored together. This is especially useful to avoid an excessive memory consumption within the server, limiting the number of screens stored at server side and allowing to delete them, in an embodiment, when the maximum number of screens is reached (for instance 5 screens).
[0090] In an embodiment the step for creating, by the server, a data structure (STATE) further comprises,
storing the content of the data structure (STATE) corresponding to each risk point in a storing space, preferably internal memory in the server, or storing the content of the data structure (STATE) corresponding to each risk point in the data which is sent to the client, and storing a hash value of said content in a storing space, preferably internal memory in the server, or cyphering the content of the data structure (STATE) corresponding to each risk point and storing said cyphered content in the data to be sent to the client.
[0094] Advantageously, this embodiment allows implementing bespoken solutions. For example, if there is not enough storing space on a server, the strategy of hashing can be used since less storing space is required.
[0095] In another embodiment of the method the step for reading the request identifier (STATE_ID) from the received request comprises:
checking the data structure (STATE) of the request identifier (STATE_ID) in a memory space, preferably the internal memory of the server, or generating a second hash of the content of the received data structure (STATE) of the data received in the request, or deciphering content of the data structure (STATE) corresponding to each risk point.
[0099] This embodiment provides a solution for how to recover de information of the request received in the server from the client. This is an advantage because it can recover the information from the request according to one of the previous alternatives for storing the content of the data structure.
[0100] In a particular embodiment the STATES are organized by the server in a third type of data structure or SCREEN and wherein, if the request is received by an external entity, then the STATES are sent to the external entity, in step f), organized in SCREENS and the external entity stores the STATES in SCREENS.
[0101] Advantageously this third type of data structure allows system scalability and it further allows organizing the STATE in, for example, one SCREEN per session. Also, the response time is reduced since the SCREENS are stored in the external entity and the information to validate is organized. The resources which were employed in the state of the art for seeking information to compare against the requests sent from client side in order to validate can be now employed in other tasks.
[0102] In an embodiment it is possible to store only the last screen within the server, and the other SCREENS (the oldest ones) within another external server. This advantageously allows reducing the memory consumption at the server side. The external server, for instance a memory Database such as Redis, may store big amounts of data in memory, without the performance overhead generated commonly within JVM and .NET “Common Language Runtime” environments due to garbage collection tasks.
[0103] In an embodiment it is possible to store only the last screen within the JVM or .NET memory and the rest of screens within the server but outside the memory controlled by execution environments garbage collector. This technique is known as off-heap memory storage.
[0104] Advantageously as a difference with the state of the art, this embodiment provides a solution for increasing the capacity of the server adding a new complementary server.
[0105] Advantageously as a difference with the state the art, this embodiment provides an integration and collaboration between external entities, such as application firewalls, and the server side applications where the invention is applied. In other words, the information required by the firewall (the SCREEN data structure) is sent to the application firewall avoiding the overhead of response parsing. Thanks to this information (SCREEN data structure) the firewall can implement validation tasks as well as additional security functionalities implemented by this kind of products (DOS attacks, load balancing, etc.). This is an advantage over HDIV open-source solution because the global security solution is better that the independent solutions (application firewall and HDIV independently).
[0106] In an embodiment, the method is applied to detect manipulation of web pages by a web client that performs a web request to a web server and detection of vulnerabilities within source code, implemented on a system that comprises:
at least one web client, at least a web server adapted to a telecommunication network in connection to the web client and the web, through which the request and the web response are sent,
where the method comprises the following steps:
a) receiving, by either the web server or an external entity, a web request from a web client, if the web request is an initial web request go to step c), b) if the web request is a non-initial web request,
reading, by either the web server or an external entity, such as a firewall, the request identifier (STATE_ID) from the received request represented by a string (STR), detecting manipulation, by either the web server or an external entity, such as a firewall, and finishing the method if the request identifier (STATE_ID) is different to the request identifier (STATE_ID) of a previous request that has been added to a data structure (STATE) created for each risk point of a web page of a previous request in the same web session, wherein a risk point is preferably a predetermined link or web form, preferably comprising parameters, detecting manipulation by either the web server or an external entity, such as a firewall, and finishing the method if the content received in the request is different to the content of the data structure (STATE) corresponding to the received request identifier (STATE_ID), if the request comprises at least an editable parameter which has been edited or completed by the client, storing ( 36 ) the representation of the data comprised in these fields on the web server, in a second type of data structure (TaintedObjects),
c) generating the web response by the web server, preferably a HTML page, d) analysing, by web server, if during the generation of the response, at least one risk point is generated, preferably link or web forms, e) if there is at least one risk point in the response,
creating, by the web server, a data structure (STATE) for each risk point, preferably link or web forms, generating and associating, by the web server, a request identifier (STATE_ID) to the data structure (STATE), if the risk point comprises at least one parameter, identifying the typology, editable or non-editable, of the at least one parameter of the risk point, preferably the non-editable typology comprises one of a check box, radio button, select and editable typology comprises one of an editable field textbox or text area,
f) performing a predetermined action if the request comprises at least one editable parameter comprising content which is used during the generation of the response by the server, preferably in SQL queries or output writes improperly programmed known as sink point and sending, from the web server, the web page to the web client or to an external entity, g) receiving, from the web client, the web page susceptible to be modified by the web client or by an external entity, h) continuing in step a) if the web client sends another web request to the web server in a same session web, preferably using one of the request identifiers (STATE_ID) generated in the step e) of the current request, or a previous request inside the same web session.
[0125] In a second aspect of the invention there is provided a system comprising
a server adapted to perform the method steps of a method according to the first aspect when they are referred to a server, a client in communication to the server through a telecommunications network adapted to perform the method steps of a method according to the first aspect when they are referred to a client.
[0128] In the present description “server” is understood as a hardware element where the server side of applications are hosted.
[0129] In an embodiment the server is a web server and the client is a web client, whereas the responses generated by the web server are web pages and the requests sent by the web client are web requests. In this embodiment, the web server may be one of APACHE, IIS, or application server, such as TOMCAT, WEBSPHERE, in such manner that the method of the first aspect of the invention may be implemented in any programming environment comprising either servers—such as in APACHE—, or application servers—such as in JAVA—. In general terms, a server is the device or machine where a web application is hosted, independently of the environment it is implemented on.
[0130] For example, in environments such as MICROSOFT or PHP, “server” may be interpreted as server (APACHE, IIS), and in environments such as JAVA, “server” would be interpreted as application server (TOMCAT).
[0131] In a third aspect of the invention there is provided an application for detection of manipulation of applications by a client that performs a request to a server and detection of vulnerabilities within source code, the application adapted to run on a server and comprising:
means for analysing whether at least one risk point is generated during the generation of the response, means for creating a data structure (STATE) for each risk point, means for associating, a request identifier (STATE_ID) to the data structure (STATE), means for checking whether the risk point comprises at least one parameter, means for identifying the typology of the at least one parameter of the risk point means for reading the request identifier (STATE_ID) from the received request preferably represented by a string (STR), means for detecting manipulation and for rejecting the request if the request identifier (STATE_ID) is different to the request identifier (STATE_ID) of a previous request that has been added to a data structure (STATE) created for each risk point of a response of a previous request in the same session, means for detecting manipulation and for rejecting the request if the content received in the request is different to the content of the data structure (STATE) corresponding to the received request identifier (STATE_ID), means for storing the representation of the editable data comprised in the request and received by the server in a second type of data structure (TaintedObjects),
[0141] In an embodiment, the application further comprises:
means for performing a predetermined action if at least some data included in the second type of data structure (TaintedObject) is used in a sink point during the generation of the response by the server or means for using functions included within libraries in the application or solutions or functions available within the server.
[0144] As a difference with the state of the art, this application also allows proactive actions in runtime; for example, allows escaping a TaintedObject used by the code in runtime, and also allows that the code for performing such actions is embedded in the server in libraries.
Advantageously, an application according to this embodiment detects when a TaintedObject is used in a sink point, for example SQL queries or writes generating a response output improperly programmed,
[0146] As a difference with the state of the art, the application and method create an alert for the server and/or performs proactive actions, preserving the security in the server.
[0147] In an embodiment of the application, it is adapted to perform the relevant steps of any one of the particular embodiments of the first aspect of the invention.
[0148] The security solutions in the state of the art mainly consider the entire client requests to be suspicious of being dangerous for the server, and thus the solutions of the state of the art tend to analyse the whole request. This invention, instead, once has analysed the integrity of non-editable data, only controls or monitors editable data within the request processing, because it is possible to trust the rest of the data due to the integrity checks implemented previously. This fact advantageously saves resources such as memory or CPU consumption.
[0149] All the features described in this specification (including the claims, description and drawings and/or all the steps of the described method can be combined in any combination, with the exception of combinations of such mutually exclusive features and/or steps.
DESCRIPTION OF THE DRAWINGS
[0150] These and other characteristics and advantages of the invention will become clearly understood in view of the detailed description of the invention which becomes apparent from preferred embodiments of the invention, given just as an example and not being limited thereto, with reference to the drawings.
[0151] FIG. 1A This figure represents an embodiment of the architecture on which a method according to the state of the art is implemented.
[0152] FIG. 1B This figure represents an embodiment of the architecture on which a method according to the invention is implemented showing a client ( 15 ) and a server ( 17 ).
[0153] FIG. 2A This figure shows an example of method steps implemented according to the invention, where a client ( 25 ), a server ( 27 ) and a web page ( 29 ) are represented.
[0154] FIG. 2B This figure shows an example of method steps implemented according to the invention, where a first type of data structure (STATE), a second type of data structure (TaintedObject) and a third type of data structure (SCREEN) are represented next to a web page ( 29 ).
[0155] FIG. 3 This figure shows a flow diagram of an embodiment of a method according to the invention.
[0156] FIG. 4 This figure shows a flow diagram of an embodiment of a method according to the invention which uses a build process technique for being implemented on a server.
[0157] FIG. 5 This figure shows a flow diagram of an embodiment of a method according to the invention which uses a runtime technique for being implemented on a server.
[0158] FIG. 6 This figure shows an exemplary scheme for illustrating the technic of propagation.
[0159] FIG. 7 This figure shows an exemplary embodiment where the method is performed on a system comprising a client ( 71 ), a server ( 75 ) and a firewall ( 73 ).
DETAILED DESCRIPTION OF THE INVENTION
[0160] Once the object of the invention has been outlined, specific non-limitative embodiments are described hereinafter.
[0161] The method according to the invention is carried out applying known techniques in order to add an additional behaviour to the server behaviour which is used for controlling the data flow globally within, for example, web applications running on servers, but without amending original source code of said applications. In an embodiment, the method is applied performing compiled code transformation:
[0162] Compiled code transformation: this technique can be applied on build process of the applications or in runtime. An example of such processes is represented in FIG. 4 for build process and in FIG. 5 for runtime process. Specifically the compiled product ( 41 ) or server application, for instance .class files in Java EE platform or .il files in .NET platform, are transformed to add the extra behaviour, and thus resulting in an amended version ( 43 ) of the server application. In the build process transformation ( 42 ), the compiled code is transformed before the deployment of the application into the server ( 44 ). In other words, the deployment product ( 43 ), for instance .war, or .ear files in Java environments, is already transformed before the deployment into the server ( 44 ).
[0163] As a way of an example, there is shown, in FIG. 1A , an embodiment of the architecture on which a method according to the state of the art may be implemented. In this case the client ( 11 ) exchanges ( 14 ) requests and responses with the server ( 13 ) in a web environment.
[0164] To avoid the weakness of the Hypertext Transfer Protocol (HTTP), a firewall ( 12 ) is used in the state of the art, which first of all parses the HTML response and afterwards uses the extracted information in order to validate the incoming requests.
[0165] In FIG. 1B there is an embodiment representing an embodiment of the architecture in which a method according to the invention may be implemented. The client ( 15 ) exchanges ( 16 ) requests and responses with the server ( 17 ) adapted to implement a method according to the invention. In this embodiment, the method is implemented as an application or subroutine ( 18 ) on the server ( 17 ) detecting manipulation of web requests received.
[0166] As a way of an example, an embodiment of the invention is shown in FIG. 2A , representing the method ( 28 ) steps implemented on the architecture described previously. The client ( 25 ) requests an initial web request ( 21 ) to the server ( 27 ). For example the client ( 25 ) requests “http://web.com” ( 21 ).
[0167] In this case the server ( 27 ), where the method ( 28 ) is implemented, analyses whether the request ( 21 ) is an initial request. In this embodiment since the request ( 21 ) is an initial request, the server ( 27 ) loads the web page ( 29 ) and checks whether there are any risk points. The server ( 27 ) creates a first type of data structure (STATE) for each risk point, as it is represented in FIG. 2B . Subsequently the server ( 27 ) associates a request identifier (STATE_ID) to the first type of data structure (STATE). In FIG. 2B a representation of three first types of data structures (STATE) is shown, first for a link, second for a form, and third for a different form. Besides, for each editable field, in this case the two text boxes, a second type of data structure is created (TaintedObject).
[0168] In this embodiment, the first types of data structures (STATE) are stored in a third type of data structure (SCREEN).
[0169] As the method steps in FIG. 2A show, the server ( 27 ), after creating the data structures (STATE) for each risk point and storing them in internal memory, allows associating an identifier (STATE_ID) for each risk point. The association is made by the web server, by modifying the response or web page, preferably adding an additional parameter to each link or URL and to each form; After associating the identifier (STATE_ID) to each risk point, the method allows sending ( 22 ) the web page ( 29 ) to the client ( 25 ), which comprises, as explained, an associated identifier (STATE_ID) for each risk point; this is represented in FIG. 23 .
[0170] The client modifies ( 23 ) the link with malware or the text boxes are edited with SQL queries in order to obtain a malicious behaviour.
[0171] The client ( 25 ) sends a new request ( 24 ) comprising one of the state and states_id (STATE_ID_1, STATE_ID_2, STATE_ID_3) for each risk point shown in FIG. 23 to the server in the same web session; the server ( 27 ) reads the new request ( 24 ) which is sent in a form of a string (STR); the server ( 27 ) checks:
if the received State identifier (STATE_ID) is the same as any of the previous identifiers (STATE_ID_1, STATE_ID_2, STATE_ID_3) created for previous requests stored in the server, and If the content of the request is the same as the content stored in the corresponding first type of structures (STATE1, STATE2, STATE3), For the editable fields, or text boxes, the server checks whether the text field data is used in an unsuitable way, for example with an unsuitable programming code, or malware programming code, known as sink points, for instance a SQL query without parameterized queries or a write without escaping the data.
[0175] For example, if the URL of the link included in the web page ( 29 ) is http://servercom?accountId=10&STATE_ID=3, the user may change the value of the parameter accountId, for instance accountId=10, in order to try to watch the account data from another user.
[0176] Thanks to the extra parameter added by the method to each link and form, in that case STATE_ID=3, it is possible to read at server side the STATE related to this link and implement the validation process using this information. In that case, the request is rejected due to the fact that the value is different from the original value.
[0177] In this embodiment, since the client ( 25 ) has manipulated the link, the loading of the web page ( 29 ) is aborted and the session ends.
[0178] If the user submit one of the web forms included in the web page ( 29 ), and the value that come from the text field is used in a sink point, the application ( 28 ) on the server ( 27 ) performs a predetermined action before the execution of the sink point, which in this embodiment is to create an alert and implement a proactive action to solve the risk such as escape the data or use a secure function instead of the original function.
[0179] In an embodiment in which there is not manipulation, the server ( 27 ) accepts the request ( 24 ) and continues processing the request ( 29 ) requested by the client ( 25 ).
[0180] As a way of an example, there is shown, in FIG. 3 , a flow diagram of an embodiment of the method. In a first step a server, receives ( 31 ) a request from a client. The server checks ( 32 ) if it is an initial request, preferably searching within a predefined list or URLs defined at the server side.
[0181] Case One: Initial Request:
[0182] The server receives ( 31 ) a request from the client which is an initial request.
[0183] The server starts generating the response ( 37 ), and analyses ( 38 ) if the response contains any risk point, in which case the server generates ( 39 ) a first data structure, or STATE, for each risk point. In order to detect the risk point the invention intercepts or extends the functions or subroutines used by the web framework or library to create links or forms. The source code is not changed or amended or updated because the extension is applied through configuration (XML or annotations) and not through updating source code.
[0184] Subsequently, the method allows the server to check ( 391 ) whether any sink point is used, i.e., if an editable parameter or TaintedObject is used as input parameter of a sink point, a predetermined action is performed ( 392 ). The server sends ( 393 ) the response to the client.
[0185] The client receives the response.
[0186] If the client does not make any other request the session expires.
[0187] If the client makes another request the process is executed again, with a non-initial request, as follows.
[0188] Case Two: The Request is Not an Initial Request:
[0189] The server receives ( 31 ) a request which is not an initial web request. The server reads ( 33 ) the web request received, and detects ( 34 ) if there is a parameter with the name STATE_ID which is the identifier of the request. If there is not a parameter named STATE_ID the request is rejected and the method ends ( 310 ). Otherwise the server reads the STATE data structure generated on a previous request, and analyses or validates ( 35 ) whether the non-editable parameters are the same as the values include within the corresponding STATE data structure, in order to determine that manipulation has not existed; in case of manipulation of any non-editable parameter, then manipulation is detected. Also, if there is some additional parameter not included within a STATE data structure, the request is rejected.
[0190] If the validation is overcome, then it is checked ( 311 ) whether there is any editable parameter included within the request; in case that there are any editable parameters comprising some content, this content is stored ( 36 ) within TaintedObjects data structure.
[0191] The server generates or renders ( 37 ) the response, and the method continues analysing ( 38 ) if the response contains any risk point, in which case the server generates ( 39 ) a first data structure, or STATE, for each risk point.
[0192] If the is any point where the server generates any new content derived from the contents stores within TaintedObjects data structure, the generated content is stored ( 36 ) within TaintedObject data structure as well. This process is known as propagation. This propagation is performed thanks to the transformation of compiled classes. This transformation is performed in load time, in runtime or in the build process. An example of propagation can be seen in FIG. 6 , where starting from having two TaintedObjects, in the FIG. 6 represented by the name of TO1 and TO2, a new object is created by adding “data” to one of them, which is represented by the name SQL, this, a new Tainted Object represented in the figure by SQL is created.
[0193] In this specification, overload or performance overhead or overhead is any combination of excess or indirect computation time, memory, bandwidth, or other resources that are required to attain a particular goal.
[0194] Subsequently, the method allows the server to check ( 391 ) whether any TaintedObject is used as input parameters in a sink point.
[0195] Examples of these sink points functions are:
Database access in Java environments where there is the risk related with SQL Injection attacks:
[0000]
public java.sql.Statement.execute*(String);
public java.sql.PreparedStatement.execute( );
Writes in the response where there is the risk related with XSS web risk:
[0000]
javax.servlet.jsp.JspWriter.print(String);
javax.servlet.jsp.JspWriter.write(String)
[0198] If the use of any TaintedObject is detected ( 391 ) as input parameter of any sink function, the invention generates a log and a proactive action is performed ( 392 ) such as escaping the content in order to avoid XSS or SQL Injection attacks. In the example below there is in example of an escape function—( 392 ) String escapedString=escapeFunction(String)—added by the invention before the sink point execution. In other words, the invention does not execute the sink point until it has analysed input parameters and executed some proactive action ( 392 ). Subsequently the sink point is executed in the same way as original source code.
[0000]
(392) String escapedString= escapeFunction(String);
(391) Statement.execute(escapedString);
[0199] Note that this extra behaviour is added within compiled classes and the server application or the application source code remains the same.
[0200] If there is any risk point within the response (link or form renderization) the invention intercepts all the server functions that process this kind of components. The functions intercepted by the invention depend on the technology used by the server.
[0201] Some examples of this type of functions using two of the most used technologies (Java, .NET) are shown below:
Java, for instance Spring MVC web framework:
[0000]
<html> <body>
(38) <form:form method=″post″ modelAttribute=″person″>
<form: input path=”name”>
</form>
</html></body>
[0203] The text above ( 38 ) represents the functions that in this case the form generates. The invention intercepts these functions in order to obtain the data stores within STATE data structures (url, parameters names, parameters values, etc.)
.NET, for instance ASP MVC framework.
[0000]
<html> <body>
(38) @using (Html.BeginForm))
{
@Html.TextBoxFor(model =>model.Name)
}
[0205] In order to measure the performance overhead avoided by the invention the table below the shows the necessary time for the core operations of the TaintedObjects propagation and monitoring algorithm. Basically there are two types of operations:
Search: in every function that may use a TaintedObject is necessary to search within TaintedObject data structure to verify if the data is tainted or not. The invention intercepts any function within the program that uses as Input data String or character type parameters. The number of search operations is directly related to the number of functions that may use TaintedObjects (any programming language type that contains String type formats or similar, for instance in Java language: String, StringBuffer, StringBuilder, Char, etc.) Insert: if any of the input parameters used by a function is Tainted the resultant Objects must be included within TaintedObject Data Structure.
[0208] In the tables below the results obtained within a Java 7 Environment are presented.
[0000]
Search
Search time
Insert
Insert time
TOTAL
operations
(ms)
operations
(ms)
overload/overhead
500
0.2 ms
250
0.1 ms
0.3 ms
1000
0.4 ms
250
0.2 ms
0.5 ms
[0209] This overload is related with the core operations of the invention but there are also additional operations that add more overload time. An average overload around 0.5 ms per request may be considered.
[0210] The impact of this overload depends on the business model of the application. Within web environments in different technologies (Java, .NET, PHP), the fastest web response time in the state of the art is usually comprised in a range of 3 ms-8 ms. The overload avoided by the invention (0.5 ms per request) is between 16%-5% (0.5 ms is the 16% of 3 ms and the 5% of 8 ms) because the most important part of web request does not include any editable data.
[0211] In a request including editable data this percentage is lower considering that in most of the cases web pages comprise a low number of editable fields compared to the total amount of non-editable fields; this is to say, there is, in most of the cases, about a 10% of editable parameters over the total number of parameters/fields.
[0212] Regarding memory consumption generated by any possible TaintedObject propagation and monitoring system, the memory consumption is directly related with the number of TaintedObjects included within the data structure and the typology of this data. For instance in Java environments, the reference to an object uses about 4-8 bytes, depending on how many bits the operating system is based on, or the program (32 or 64 bytes). Besides, the data related with the origin of the TaintedObject data is stored (http parameter, for example, accountID, name or equivalent, etc.), thus consuming more memory space. TaintedObjects are created for a particular HTTP parameter, for example accountID; this is what is referred herein by “origin”.
[0000]
Number of
Tainted Objects
Tainted DataStructure
Size per item
TOTAL SIZE
200
20 bytes
6 bytes
1.3 KB
500
20 bytes
6
3 KB
[0213] The size per item is the memory consumption due to a single web request. A server receives commonly an average of 300 request per second, so the algorithm may generate a memory consumption of 300 KB-900 KB per second, or around 18 MB-54 MB per minute.
[0214] The invention reduces the memory consumption because, unlike the state of the art solutions which only consider tainted data, the data that come from editable fields. For instance in requests that don't include editable data (usually 80-90% of the web request because links doesn't have editable data) the invention don't use memory at all. In the rest of the requests (20-10%) the amount of consumed memory is lower due to the invention only monitor editable data.
[0215] As a way of example, in FIG. 7 there is shown an scenario in which the data structures (STATE) are stored in SCREENS, said SCREENS being sent in the response towards an external entity ( 73 ), such as a firewall, and the firewall being the one performing the steps of the method corresponding to the validation of non-editable parameters, this is, some of the steps of step b of a method according to the invention.
[0216] This is an embodiment wherein the method, in the step for storing all STATE generated for each risk point in a SCREEN, is performed in memory of an external entity ( 73 ).
[0217] The scenario in FIG. 7 presents:
A client ( 71 ) sends a request ( 72 ) towards a server ( 75 ), the request being intercepted by the firewall ( 73 ), The firewall ( 73 ) receives ( 31 ), a web request from the client ( 71 ), and forwards the request ( 74 ) towards the server ( 75 ), where other method steps are performed, namely:
creating, by the server ( 75 ), a STATE for each risk point, associating, by the server ( 75 ), a STATE_ID to the STATE, if the risk point comprises at least one parameter, identifying the typology, editable or non-editable, of the at least one parameter of the risk point, preferably the non-editable typology comprises one of a check box, radio button, select and editable typology comprises one of an editable field textbox or text area performing a predetermined action ( 392 ) if the request comprises at least one editable parameter comprising content which is used ( 391 ) during the generation of the response by the server, preferably in SQL queries or writes known as sink point, creating a SCREEN comprising the STATES created for the current session,
Subsequently the server ( 75 ) sends ( 76 ) the response together with the SCREEN created for the web session to the firewall ( 73 ), The firewall ( 73 ) filters the SCREEN and the response. The response is sent towards the client ( 71 ) whereas the SCREEN is stored in the firewall. Advantageously, this method saves internal memory in the server ( 75 ) and improves the performance of the firewall avoiding the parsing process of the response, receiving, from the client ( 71 ), the web page susceptible to be modified by the client ( 71 ), restarting the process if the client ( 71 ) sends another web request to the server ( 75 ) in a same session web, preferably using a request identifiers (STATE_ID) generated in the step f) of the current request, or a previous request inside the same web session.
[0229] Subsequently, for every request within the same web session, the client ( 71 ) sends ( 72 ) requests which the firewall ( 73 ) intercepts. The firewall ( 73 ) then sends the request ( 74 ) together with the STATE or, in the case of the figure, the SCREEN which has been created for the current web session. As long as the same web session continues, the firewall ( 73 ) stores the SCREEN coming from the server ( 75 ), and checks whether the incoming requests must be rejected according to the comparison of the incoming identifiers with the STATE_ID comprised in the SCREEN.
[0230] The advantages of structuring the data in the structure SCREEN and sending it to the firewall ( 73 ) embedded in the response are:
response time is speeded up within the firewall, with respect to the state of the art where the firewall needs to parse and analyse the whole response generated at the server, preferably in HTML, XML, JSON formats, and memory space within the server ( 75 ) is saved as neither STATE nor SCREENS need to be stored in the server ( 75 ).
[0233] Particular Example: Native Mobile Application:
[0234] In this particular example, the following steps are implemented:
A native mobile application, for instance an Android or IOS app ( 71 ), sends a request ( 72 ) towards a server ( 75 ), the request being intercepted by the firewall ( 73 ), The firewall ( 73 ) receives ( 31 ), the request from the client ( 71 ), and forwards the request ( 74 ) towards the server ( 75 ), where other method steps are performed, namely:
creating, by the server ( 75 ), a data structure (STATE) for each risk point, preferably link or web forms, associating, by the server ( 75 ), a request identifier (STATE_ID) to the data structure (STATE), if the risk point comprises at least one parameter, identifying the typology of the at least one parameter of the risk point wherein the risk point is preferably a of non-editable field, more preferably a check box, radio button, select and an editable field textbox or text area performing a predetermined action ( 392 ) if the request comprises at least one editable parameter comprising content which is used ( 391 ) during the generation of the response by the server, preferably in SQL queries or writes known as sink point, creating a SCREEN comprising the STATES created for the current session.
Subsequently the server ( 75 ) sends ( 76 ) the response together with the SCREEN created for the session to the firewall ( 73 ), The firewall ( 73 ) filters the SCREEN and the response. The response is sent towards the client ( 71 ) whereas the SCREEN is stored in the firewall. Advantageously, this method saves internal memory in the server ( 75 ) and improves the response time of the firewall avoiding the parsing time of the whole response, receiving, from the client ( 71 ), the data susceptible to be modified by the client ( 71 ), continuing the process if the client ( 71 ) sends another request to the server ( 75 ) in a same session, using one of the request identifiers (STATE_ID) generated previously in the current request, or a previous request inside the same session; subsequently, for every non-initial request from the client the firewall ( 73 ) forwards towards the server ( 75 ) the editable parameters from the STATE, which are received in every request, in the case the request comprises editable parameters.
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The present invention relates to a solution to improve the security of applications. Particularly, the invention relates to the control of the whole lifecycle of data traffic between a client and a server applying also internal data flow system within the server only for editable data. The invention presents a method for detection of manipulation of data ( 29 ) by a client ( 11, 15, 25 ) that performs a request to a server ( 13, 17, 27 ) and detection of vulnerabilities within source code. The invention also presents an application and a system for the detection of manipulation in applications. As a particular example, the invention presents a method for detection of manipulation of web pages in HTTP.
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BACKGROUND OF THE INVENTION
Copper and copper base alloys are widely used in industry due to their good heat conductivity and corrosion resistance, such as pipelines of cooling systems and heat exchangers, but copper and its alloys usually suffer severe corrosion in acidic media. Using inhibitors to prevent copper corrosion is the most economical anti-corrosion method for many applications of copper. Benzotriazole (BTA, C 6 H 4 N 3 H) and its derivatives (e.g., 1-methyl-benzotriazole, BTAM, tolyltriazole, also referred to as TTA or carboxybenzo-triazole CBT) are so far the best inhibitors in preventing the corrosion of copper and its alloys in industry. The patents pertinent to the BTA copper corrosion inhibition include U.S. Pat. Nos. 3,653,931; 3,791,803; 3,985,503; 4,744,950; 5,128,065; and 5,156,769. However, the inhibition efficiency of BTA and its derivatives drops dramatically in acid solutions, although the film formed in acid solutions is thicker than those formed in neutral and alkaline media. For example, the low inhibition efficiency of BTA/its derivatives in acid solution causes a problem in pickling (using acid solutions to dissolve the scales); too much copper is dissolved thus reducing service life. The low efficiency of commercially available inhibitors in acid also means that inhibitors are not available for preventing scale formation (e.g., calcium carbonate) in cooling systems which are nominally neutral but become acidic because of absorption of carbon dioxide and more corrosive toward copper. Similarly, Cu can be corroded by acidic rain, cooling, sea and potable water. In the case of slightly acidic potable waters, the copper levels in the water can become unacceptably high for consumption at levels well below those that cause degradation of the copper pipes. Therefore, efforts are underway to develop better inhibitors in these acidic environments.
Since the good inhibiting nature of BTA is known to be due to formation of a stable polymer film that occurs on copper surfaces in neutral and alkaline solution, efforts are underway to develop similar dense, thick films on copper in acidic media. BTA by itself is unsatisfactory in this regard.
Although potassium iodide (KI) has been used as an additive to improve the inhibition efficiency of some other organic inhibitors in preventing corrosion of irons and steels due to a synergistic effect, e.g., used with trans-cinnamaldehyde and alkynols to decrease the corrosion of steel in 20% HCl solution, it or other iodide compounds have not been adopted in copper corrosion prevention. Patents describing the corrosion inhibiting feature of potassium iodide, or iodide ion, include U.S. Pat. Nos. 2,559,580; 2,567,156; 3,816,322; 4,143,119; 4,640,713; and 4,851,149.
Although there were no suggestions that a combination of iodide compounds with BTA might increase the inhibiting property of the latter, we decided to explore such an approach and observed quite unexpectedly that such combination possessed superior anti-corrosion properties. This unexpected result led to further studies of the mechanism of the protective properties of the said combination of BTA and iodide ions. As mentioned earlier, the iodide ions are effective additives to some other organic inhibitors of corrosion of iron and steel. When used with trans-cinnamaldehyde and alkynols to decrease the corrosion of steel in 20% HCl solution, it is reported to do so by electrostatic attraction rather than film formation. Consequently, iodide compounds have not been adopted in copper corrosion prevention. The conventional explanation of the electrostatic attraction is that an attractive force exists between adsorbed anions on the metal and the organic cations, thus the adsorption of the organic cations on the metal surface is improved.
Our work has shown, however, that in the case of copper, the effects of the iodide ions on improving the inhibition efficiency of BTA/its derivatives is more complicated than simply an electrostatic force effect; the iodide ions actually form a polymer-like, dense, thick (400nm) film with copper and BTA/its derivatives, thereby possibly explaining the selective nature of BTA+KI (or other iodide compounds) for specifically functioning as a good inhibitor of copper, but not steels, etc. This multi-compound inhibitor provides a strong synergistic inhibition of copper corrosion in a wide variety of environments.
Most of the art that relates to the inhibition of corrosion of copper-bearing metals in aqueous systems requires the constant presence of the inhibitor in the aqueous medium. Only one of the examples cited, U.S. Pat. No. 4,744,950, addresses the method of inhibiting corrosion by formation of a stable and durable inhibiting film which does not require maintaining a level of inhibitor in the aqueous medium. The present invention provides an alternative to the protection of the copper bearing metals by formation of a protective film on its surface, which does not require maintenance of a level of inhibitor in the aqueous medium. The measured thickness of the formed film (400 nm) which is much greater than the reported thickness of the BTA film (5 nm) suggests a superior property of the composition and a method of using it as described in this invention.
SUMMARY OF THE INVENTION
In accordance with the present invention, a new inhibitor of high efficiency for preventing copper corrosion and methods related thereto, is presented. In the preferred embodiment this inhibitor comprises a mixtures of iodide, e.g. added as KI or NaI, and BTA and its derivatives and was developed for preventing copper corrosion in various acidic environments, such as acid and acidic media (e.g., acid rain, cooling, sea and potable water). Weight loss tests and electrochemical techniques demonstrate that a strong synergistic inhibition exists when BTA/its derivatives are used with iodide/bromide to prevent the corrosion of copper. The synergistic effect is largely due to forming an inhibitor film of a new complex, CuIBTA. This new complex film greatly depresses the anodic (corrosion) reaction.
OBJECTS OF THE INVENTION
An object of this invention is to develop a new inhibitor for preventing copper corrosion.
It is also an object of the invention to provide a method of preparation of the new inhibitor.
Another object of this invention is to provide a method of application of the aforementioned inhibitor.
These and other objects and advantages of this invention over prior art and a better understanding of its use will become readily apparent from the following description and are particularly delineated in the appended claims.
DESCRIPTION OF THE DRAWINGS
FIG. 1. Anodic polarization curves for copper in 0.5M H 2 SO 4 (H 2 SO 4 ), in 0.5M H 2 SO 4 -0.01M KI (KI), in 0.5M H 2 SO 4 -0.02M BTA (BTA), and in 0.5M H 2 SO 4 -0.01M BTA-0.01M KI (BTA+KI).
FIG. 2. Polarization curve of Cu in the 0.01M BTA+0.01M KI inhibited pH3 tap water solution.
FIG. 3. Polarization curve of Cu in the 0.01M TTA+0.01M KI inhibited pH3 tap water solution.
FIG. 4. Frequency-time relationship of the quartz microbalance for Cu in the BTA inhibited pH3 Na 2 SO 4 solution.
FIG. 5. Frequency-time relationship of the quartz microbalance for Cu in the BTA+KI inhibited pH3 Na 2 SO 4 solution.
FIG. 6. Frequency-time relationship of the quartz microbalance for Cu in the TTA inhibited pH3 Na 2 SO 4 solution.
FIG. 7. Frequency-time relationship of the quartz microbalance for Cu in the TTA+KI inhibited pH3 Na 2 SO 4 solution.
DETAILED DESCRIPTION OF THE INVENTION
The present invention describes the new inhibitor for preventing copper corrosion. During the course of detailed studies involving investigation of corrosion prevention, we developed an unusually efficient inhibitor based on a synergistic inhibition effect due to formation of the inhibitor film of a new complex between BTA and iodide ions, CuIBTA.
A detailed embodiment of the present invention is herein described. However, it is understood that the disclosed preferred embodiment is merely illustrative of the invention which may be embodied in various forms. Accordingly, specific details disclosed herein are not to be interpreted as limiting, but merely as a support for the invention as claimed and as appropriate representation for teaching one skilled in the art to variously employ the present invention in any appropriate embodiment.
The examples described below provide supporting evidence for the proposed conclusions that the combination of iodide with BTA/its derivatives (e.g., TFA) significantly decreases the corrosion rate of copper in various acidic environments, such as acid and acidified potable, fresh, and sea water, and as such will prevent corrosion of copper in acidic solutions in contrast to commercially available inhibitors which have a low efficiency in acids. Even in neutral solutions in which BTA is a good inhibitor by itself, some improvement is observed when iodide is added. The electrochemical studies and weight loss tests indicate a synergistic effect of BTA/derivatives and iodide on inhibiting copper corrosion by the formation of an I containing BTA film on the copper surface. The stability of the inhibitor films on the copper surface is also improved by adding iodide to BTA/its derivatives, as shown in experiments in which the performance of the preformed film on the copper was determined during exposure to corrosives which did not contain the inhibitor. The high inhibition efficiency and stability of films of I containing BTA/its derivatives shows great potential in preventing corrosion in acids and acidified and neutral media, including solutions used during commercial pickling processes, fresh and sea water used in cooling systems and heat exchangers, and potable water.
The mechanism of the synergistic effect is not simply an electrostatic force between adsorbed I anions and organic cations but the formation of a thick inhibitor film of the Cu-I-BTA/its derivatives complex. This film greatly depresses the anodic copper dissolution reaction.
Experimental Procedure
The experimental methods employed in the present invention are based on the following procedures.
Commercial purity (99.9%) copper was used as the samples in the experiments. The samples were mechanically polished sequentially down to 0.05 mm dia. alumina powder. After the polishing, the samples were degreased in acetone, washed with distilled water and dried in flowing compressed dry nitrogen gas. Reagent grade chemicals and double distilled water were used to prepare the electrolytes: oxygenated <pH1 solutions: 0.5M H 2 SO 4 , 0.5M H 2 SO 4 -0.01M KT, 0.5M H 2 SO 4 -0.01M (or 0.02M or 0.1M BTA) BTA, and 0.5M H 2 SO 4 -0.01M BTA-0.01M KI (or NaI or KBr); pH3 solutions: 0.1M Na 2 SO 4 -x H 2 SO 4 , 0.1M Na 2 SO 4 -x H 2 SO 4 -0.01M BTA (or TTA or CBT), 0.1M Na 2 SO 4 -x H 2 SO 4 -0.01M BTA (or TTA or CBT)-0.01M KI, where x means adding enough H 2 SO 4 to make a pH3 solution; near neutral solutions: 3.5% NaCl, 3.5% NaCl-0.05M BTA, and 3.5% NaCl-0.05M BTA-0.01M KI, 0.1M Na 2 SO 4 , 0.1M Na 2 SO 4 +0.01M BTA, and 0.1M Na 2 SO 4 +0.01M BTA+0.01M KI. Some pH3 solutions were also made by adding H 2 SO 4 , KI and BTA or TTA to tap water. To prove that the synergistic effect exists when BTA and iodide are used together to prevent copper corrosion, 0.5M H 2 SO 4 -0.02M BTA, 0.5M H 2 SO 4 -0.1M BTA, and 0.5M H 2 SO 4 -0.01M KI were also used in measuring the polarization curves and polarization resistance, R p .
An EG&G PAR 273 Potentiostat, a standard cell and samples with one cm 2 area exposed, and software packages M342C and 270, were used to obtain the polarization curves, corrosion current and polarization resistance (by the linear polarization method, ±10 mV), and cyclic voltammetry curves. The scan rate in the potentiodynamic experiments was 0.1 mV s -1 . A quartz microbalance was used to study the stability of the inhibitor films. A small amount of oxygen gas was introduced to the electrochemical cells in the polarization experiments, except in the weight-loss, quartz microbalance, and x-ray photoelectron spectroscopy (XPS) experiments where the cells were open to the laboratory atmosphere.
Example 1
Weight Loss and Average Corrosion Rate Test
The flat copper samples with 1 cm 2 area were exposed to the media in a container filled with solutions A, B or C after first weighing as in the description for Table 1 and kept immersed for a period of one month. After removal from the media and drying, the weights of the samples were again measured. The samples were returned to the respective containers and kept for an additional month and weighed again. From the weight loss (weight measured after immersion subtracted from weight measured before immersion), the average corrosion rate for each period was calculated as the weight loss times twice the Faraday constant divided by the product of the immersion time (one or two months), the copper surface area and the atomic weight of copper.
TABLE 1______________________________________Weight loss results (g) and calculated corrosion rates (μA cm.sup.-2)so-lu-tionsΔ1 Δ2 .sup.i 1.corr. .sup.i 2.corr. W.sub.0 W.sub.1 W.sub.2______________________________________A 0.0362 0.0691 21.06 40.20 0.9599 0.9237 0.8546B 0.0066 0.0136 3.83 7.90 1.1069 1.1003 1.0867C 0.0040 0.0082 2.30 4.77 0.9054 0.9014 0.8932______________________________________ Notes: A, 0.5M H.sub.2 SO.sub.4 B, 0.5M H.sub.2 SO.sub.4 + 0.01M BTA C, 0.5M H.sub.2 SO.sub.4 + 0.01M BTA + 0.01M KI Δ1 = W.sub.1 - W.sub.0 and Δ2 = W.sub.2 - W.sub.1 where W.sub.0, W.sub.1 and W.sub.2 are the original weight of the samples, the weight after one month in the solutions and after two months in the solutions, respectively. .sup.i 1,corr. and .sup.i 2,corr. are the corrosion currents calculated from Δ1 and Δ2, respectively.
The cells were open to the laboratory air.
Example 2
Polarization Resistance Measurement
The polarization resistance, R p , was measured in-situ during the immersions of the copper specimens in the different solutions shown in Table 2 by the standard linear polarization method and the corrosion rate (as a function of time during each immersion period) was calculated for each R p value. An increase in polarization resistance corresponds to a decrease in corrosion rate. The obtained values are shown in Table 2.
TABLE 2______________________________________Polarization resistance and corrosion current by the linearpolarization method R p .sup.i corr.solutions (kΩ cm.sup.2) (μA cm.sup.-2)______________________________________0.5M H.sub.2 SO.sub.4 (A) 0.5628 43.570.5M H.sub.2 SO.sub.4 + 0.01M KI 0.3068 67.290.5M H.sub.2 SO.sub.4 + 0.01M BTA (B) 1.605 17.070.5M H.sub.2 SO.sub.4 + 0.02M BTA 3.880 14.610.5M H.sub.2 SO.sub.4 + 0.1M BTA 5.310 13.70.5M H.sub.2 SO.sub.4 +0.01M BTA + 10.68 10.500.01M KI(C)______________________________________ Note: Oxygen was introduced into the cell during the experiments.
Tables 1 and 2 give the results of the weight loss tests and average corrosion rates of copper from the weight loss data and by the linear polarization method in the different solutions. The data in Table 2 also show that KI added to 0.5M H 2 SO 4 by itself increases the corrosion rate of copper over that of the 0.5M H 2 SO 4 solution, whereas the addition of BTA by itself to sulfuric acid decreases the corrosion rate. However, increasing amounts of BTA do not have a proportionally larger inhibition efficiency, i.e., there seems to be a saturation concentration above which BTA increases the inhibition efficiency very slightly. This known trend is also indicated in the data in Table 2. It is very interesting to note that the corrosion rate of copper is smallest in the solution containing both BTA and KI (BTA+KI solution), as shown in Tables 1 and 2. NaI showed a similar effect as KI. Actually, using both BTA and KI in the sulfuric acid solution decreases the corrosion rate more than using either BTA or KI alone, indicating that BTA and iodide ion have a synergistic effect to prevent copper corrosion. KBr showed also an inhibiting effect but less so then KI. It can be envisioned that other halogens can provide a similar synergistic effect.
Example 3
Polarization Measurements
The flat copper samples with 1 cm 2 area were exposed to the media of pH ranging from <1 to 7 i.e., ranging in pH from strongly acid to neutral, in a container. Using a power supply the potential applied to the copper/solution interface was increased in the positive direction corresponding to an increasing driving force for copper dissolution, and the rate of copper dissolution was recorded as the measured current, I a , flowing in the circuit. The resulting curves are referred to as polarization curves.
FIGS. 1 to 3 are the measured polarization curves for different solutions at different acid strengths. FIG. 1 is for the strongly acid pH<1 solutions. In the upper section of FIG. 1, the current, I a , is a measure of the copper dissolution rate and is seen to be much lower for the BTA+KI solution than the other solutions consistent with the data in Tables 1 and 2. In fact, the copper dissolution rate is so low for the BTA+KI solution that the measured current in the lower potential region (-250 to 150 mV in FIG. 1) is cathodic (lower section) as a result of the small cathodic currents of the reduction reactions, oxygen and/or hydrogen reduction. Thus, the addition of both 0.01M BTA and 0.01M KI to the solution dramatically depresses the copper dissolution rate compared to that for copper in 0.5M H 2 SO 4 -0.01M BTA, especially in the low potential region (up to 4 orders of magnitude below 600 mV vs SCE). The BTA curve shows much higher copper dissolution rates with only some depression of the rate at potentials more positive than the peak A potential before again rising steeply with increasing potential. Peak A in FIG. 1 (BTA solution) is known from our work and others (R. Alkire and A. Cangellari, J. Electrochem. Soc., 136, 913, 1989) to be due to the formation of an inhibitor film. Studies of the BTA film have revealed that the degree of the polymerization of the CuBTA film has a more profound effect on inhibiting copper corrosion than the thickness of the inhibitor film (Brusic, et al. J. Electrochem. Soc., 138, 2253, 1991).
Similarly, peak I in the BTA+KI solution (FIG. 1) is the formation of the inhibitor film. It is known that CuI-organic ligand complexes usually have a polymeric structure. This polymeric structure of Cu(IBTA) film may explain the high inhibition effect when the inhibitor film is still thin at the beginning of the film formation, i.e., the total current becomes cathodic at potentials more noble (positive) than the potential of the film formation (I) (FIG. 1). Our XPS results also support this Cu-iodide-organic polymeric structure. Note that peak 1 forms at a lower potential than peak A in the BTA solution, so that the potential range of protective film stability in the BTA+KI solution is larger, being extended in both directions compared to the BTA solution. Peak B in the BTA+KI solution represents a further increase in protective nature of the film. Thus, the addition of KI appears to cause a remarkable downward shift of the polarization curve for copper dissolution in the noble direction. It is obvious, by comparing the curves in FIG. 1, that the polarization curve of copper in the solution having both BTA and KI is very different from those of copper in the solutions having only BTA or KI, and they do not have a superimposed relationship. This again shows that BTA and KI have a synergistic effect in inhibiting the corrosion of copper in the sulfuric acid. Therefore, the inhibitor 0.01M BTA+0.01M KI prevents copper corrosion in a very wide range of potential for this very acidic condition with a much higher efficiency than BTA by itself, and thus can be used in widely different oxidizing and reducing environments.
FIGS. 2 and 3 show the copper dissolution polarization curves for pH3. Again, the addition of iodide to the BTA had a remarkable effect in these tests. FIGS. 2 and 3 show the polarization curves in the BTA+KI and TTA+KI inhibited pH3 solutions. Cathodic current is also observed over a potential range more positive than the first anodic peak, similar to FIG. 1, indicating a strong inhibition efficiency. Comparing FIGS. 2 and 3, the inhibiting efficiency of the BTA+KI inhibitor appears to be somewhat better than that of the TTA+KI inhibitor in this pH3 solution. In addition, even in neutral solutions (NaCl or Na 2 SO 4 ) for which BTA by itself is already a good inhibitor, some improvement was noted when iodide was added.
Example 4
Quartz Microbalance Measurements
Quartz microbalance measurements were also carried out to study not only the efficiency of the new inhibitors but also the stability of the inhibitor films on the copper surface, stability being a measure of the durability of the film after the inhibitor has been removed from the aqueous phase. FIGS. 4 to 7 show the stability of different inhibitor films following removal of the inhibitor from the corrosive pH3 solution. An increase of the frequency means the sample has lost mass, so the faster the increase the higher the corrosion rate. Conversely, the slower the increase of the frequency in FIGS. 4 to 7, the lower the corrosion rate and the more stable the previously formed inhibitor film on the copper surface. Comparing FIGS. 4 and 5, the increase of the frequency of the previously formed BTA+KI inhibitor film is smaller than that for the previously formed BTA inhibitor film, indicating the BTA+KI inhibitor film is more stable. A similar phenomenon was observed for TTA and TTA+KI inhibitor films (comparing FIGS. 6 and 7). FIGS. 4 and 6 also show that the TTA inhibitor film is more stable than the BTA film. By comparison of FIGS. 4 to 7, it can be seen that the most stable inhibitor film in pH3 solution is that formed in the TTA+KI inhibited solution. In situations where the inhibitor would not be added to the aqueous phase during service, e.g., potable water, stability of the (preformed) inhibitor film on the copper surface is extremely important for protection against corrosion in the initial service period when the natural protective film develops.
Beside Benzotriazole (BTA) and tolyltriazole (TTA), carboxybenzotriazole (CBT) was tested and proved to be very effective in corrosion inhibition. Other derivatives of BTA may be used in preparation of the inhibitor disclosed herein.
In the preferred embodiment of this invention, the preparation of the corrosion inhibitor may involve adding (in either powder or liquid form, with or without mixing, mixed together or separately) the BTA/its derivatives and a compound supplying iodide or bromide ions or a compound which upon dissolving in the media forms the above said ionic species or supplying the two main ingredients to water or aqueous medium at the concentration ranging from 0.0001M to the upper concentration limited by their solubility, and in molar ratio based on molar concentration ranging from 1:100 to 100:1.
Inhibition of corrosion in a copper or copper base alloy can be achieved by supplying BTA/its derivatives and iodide (or bromide, or other halogen) ions into the media in contact with the copper or its alloys in proper concentration (ranging up to the solubility limits). To our best knowledge, the corrosion protection is achieved by the formation of the protective polymer-like film. Therefore, corrosion prevention can be envisioned by the pretreatment of copper and its alloys by formation of the said polymer film prior to the exposure to the corrosion media. Another technique would involve providing the essential ingredients to the media in contact with existing copper and its alloy systems. The recommended final concentration of BTA/its derivatives and of KI will depend on the strength of the corrosive media, including pH and nature and concentration of oxidants, e.g., in some cases 0.01M BTA/0.01M KI may be adequate but much higher and lower concentrations and different ratios of BTA and KI may also be prescribed.
Because of the long lasting and durable nature of the protective film, the application of the said anti-corrosion protective composition may be carded out in many ways. It can be used as a preliminary protective agent before the metal surface is exposed to the aggressive medium, it can be used on an intermittent basis and, obviously, continuous addition of the materials to form the said composition is also a viable means of usage.
Thus is described our invention and the manner and process of preparing it and using it in such full, clear, concise, and exact terms so as to enable any person skilled in art to which it pertains, or with which it pertains, or which is most nearly connected, to make and use the same.
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A corrosion inhibitor composition and a method for employing the same to prevent corrosion of copper and copper containing metals in contact are disclosed. Protection is afforded thereto by contacting the metal surface with the medium containing sufficient amount of benzotriazole/its derivatives and halogen, preferentially iodide or bromide ions. The inhibitor has particular utility in protecting metal surfaces which are subject to corrosion in aggressive aqueous systems.
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BACKGROUND OF THE INVENTION
The invention relates to generally welding machines for joining the laminations of a stack of stator cores to form a unitary assembly, and particularly to arc welding type machines.
Several prior art patents have been found to be of interest in reviewing machines in the arc welding field.
U.S. Pat. No. 4,114,019, of Sandor, Sept. 12, 1978, discloses a machine which utilizes a moving welding head which is moved relative to laminations of core-plated silicon steel. The essence of the invention is that operating current is limited to about 170 amps, and the arc welding microwire is held to a diameter of no greater than 0.050 inches, so that a weld bead which remains in molten form for only a few seconds will not trap the gaseous portions of the melted core plate and result in a porous weld.
U.S. Pat. No. 4,056,705, of Linam et al, Nov. 1, 1977, discloses a welding machine structure, wherein a plurality of welding torches are carried on a horizontal overhead beam, and a plurality of generally cylindrical workpieces are moved horizontally beneath the welding torches. The gist of the invention is to control the speed of the horizontal movement and to use scanner means on the welding guns to sequentially activate and deactivate the weld guns.
U.S. Pat. No. 4,229,642, of Sakurai et al, Oct. 21, 1980, discloses a large scale welding machine having a frame-supported, horizontally movable, truck which carries a horizontal workpiece on its central axis, and the truck is fixedly positioned, i.e., grossly positioned to descrete predetermined work stations along the track to get within welding range of the welding head. The welding head is carried on a short horizontal slide and is capable of performing a horizontal bead of weld on the workpiece.
U.S. Pat. No. 4,129,771, of Pinettes et al, Dec. 12, 1978, discloses a method for butt welding cylindrical metal rods, wherein a plurality of rods are vertically positioned above one another and butted end-to-end. A pair of rods to be welded are held between work tongs or chucks, and a welding torch is carried midway between the workholding tongs. The workpieces are rotated and a butt weld is formed at the juncture of the workpiece ends. After forming a butt weld, the workpieces are vertically moved to present the next butt ends to the welding torch. Thus, vertical movement is merely sequential to move the ends of the workpiece to the torch station following a weld operation.
U.S. Pat. 1,453,026, of Smith, Apr. 24, 1923, discloses a single electrode machine of the conventional arc welding type, which mounts the welding electrode vertically above the workpiece. The workpiece may be rotated to form a circular girth weld, or the workpiece may be (generally) longitudinally moved in front of the vertical electrode to weld a curvilinear shape on the workpiece.
The prior art machines which utilize a moving head-especially of the heliarc welding type, wherein an inert gas must be supplied to the welding zone to prevent oxidation of the weld-generally have certain drawbacks. The hoses, which supply the gas, and the wire feed spool, which feeds a wire-type electrode through the center of a welding gun, are difficult to move without causing wear on the flexing members and/or interfering with machine slide movements.
The machines which utilize horizontally-held workpieces moving beneath a vertical welding head, generally have the following drawbacks: (a) the workpiece carrying slide can become prohibitively long, thus taking up large floor space at the machine site; (b) the only effective weld which can be laid down on the workpiece is the weld on top of the work because it is very difficult to weld from underneath the workpiece and maintain the bead form. Thus, such machines are generally restricted to effectively using only one welding head.
Applicant has determined that the most effective type of machine for consistent quality control of weld, and for ease of machine movements and maintenance of welding head components, is that of a structure which supports the workpiece in a vertical attitude and moves the workpiece past a stationary heliarc welding head. A plurality of welding heads may be positioned radially around a workpiece and the welding heads may thereby simultaneous weld beads of identical quality.
Applicant's inventive structure has therefore obviated the difficulties inherent in the prior art devices.
SUMMARY OF THE INVENTION
The invention is shown embodied in an automatic welding machine, which utilizes a base frame having a vertical slideway thereon. A work slide is movably carried on the vertical slideway and is powered in a vertical manner by a motor and ball screw combination. The workslide has a headstock centering device at the one end which is a conical machine center with a vertical cone axis, and a footstock portion, having a similar machine center, is carried at the opposite end of the slide. The centers are adjustably positioned with respect to one another along an adjustment bar, to accomodate varying workpiece mandrels. The workpiece is comprised generally of a stack of laminations which are to be welded to form a stator core. The stator core laminations may be stacked in spaced groups along a workpiece mandrel for commonality of workpiece holding during the welding process. The inventive workpiece machine further includes at least one welding head which is carried in a bracket on the machine frame, and the welding head is adjustably positioned on the bracket and locked in position. The welding head is adjusted to maintain a fixed gap from a vertically movable workpiece surface during the workpiece excursion through the welding zone. A plurality of welding heads may be usefully employed, to create plural welds, and the workpiece may be manually rotatably indexed for multiple groups of weld beads. The machine slide is automatically driven along its vertical linear path and switching means is provided to signal the start and stop points of weld application.
It is an object of the present invention to provide a machine structure which utilizes vertical travel of a workpiece for quality application of plural welds on a workpiece.
It is a further object of the present invention to provide for stationary weld heads on the machine to create a simpler machine structure by obviating difficulties with heliarc weld hoses and electrodes and maintenance thereof.
It is still a further object of the present invention to provide a machine structure which is readily accessible by a machine operator, for inserting and removing workpieces at the workholding site.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an automatic welding machine.
FIG. 2 is an enlarged view of the machine control panel of FIG. 1.
FIG. 3 is a perspective view in partial broken-away section illustrating basic machine structure and having the workpiece removed for clarity.
FIG. 4 is a right side elevational section taken through the machine workholding slide and drive screw assembly.
FIG. 5 is an enlarged view of a welding tip in relation to a workpiece.
FIG. 6 is an exploded perspective view of a plurality of workpiece stacks and workholding mandrel.
FIG. 7 is a perspective view of a finished workpiece.
FIG. 8 is a right side elevational section through the headstock clamping center.
FIG. 9 is an exploded perspective view of a welding torch mounting assembly.
FIG. 10 is a front elevational view of the machine workpiece slide undergoing translatory movement and further depicting limit switch actuation points.
FIG. 11 is a top plan view in partial section showing the machine slide, workpiece, and related torches mounted to the machine frame.
FIG. 12a and FIG. 12b are the electric schematics for the machine.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings and particularly to FIG. 1 thereof, there is shown an overall perspective view of an automatic welding machine 10 for welding stator core assemblies or workpiece 11 and the like. The machine 10 has a base frame 12 manufactured from 5 tubular steel of square cross-section, and the frame 12 is of a generally open construction, that is, having no side or back plates confining the interior of the structure. The frame 12 has a pair of spaced-apart vertical column members 13, 14, at its rear corners, from which depend the rest of the machine 10. The upright members 13, 14, are welded to a pair of horizontal foot members 15, 16, and braced therebetween with gussets 17, to maintain squareness of the two. The topmost end of the vertical members 13, 14, have a square tubular frame welded thereto, which consists of a back member 18, two side members 19, 20, and a front cross bar 21 all lying horizontally and welded together. The side members 19,20 and front bar 21 are fitted with curtain rings 22, and shielding curtains 23 are hung from the rings 22 to prevent weld spatter and excess arc lighting to escape from the interior of the structure.
In the embodiment shown, the welding curtain 23 is plastic, and gold-colored, to deflect and defuse rays, but it may be appreciated that other colors of curtains may be employed to filter certain visible and invisible rays, and various thicknesses and layers of curtains may be employed as well. The colored welding curtain 23 employed is transparent, to permit visual inspection of the interior of the machine 10 during the welding process, but it may be appreciated that opaque curtains may be employed if desired.
At a point spaced below the topmost end of the vertical members 13, 14, a welding support structure 24 is fabricated, comprising a three-sided or U-shaped element lying horizontally on its side, wherein two legs 25, 26 of the U-shaped member extend along the sides of the base frame 12 from the vertical members 13, 14, and the tying member 27 extends along the back of the unit between the members 13, 14. A pair of short vertical members 28, 29, are fabricated at the frontmost corners of the welding support assembly 24 and the entire unit is welded to form a unitary base frame 12. The rearmost interior portion of the base frame 12 supports a vertically movable machine or work slide assembly 30 which will be described further in conjunction with FIG. 3. The welding support structure 24 carries heliarc welding torches, or welding heads or guns 31, which will be described further in conjuction with FIGS. 3 and 4.
Actual machine power for welding is obtained from commercial units which are stacked in layers at the sides of the machine. The power source 32 for the welder forms a base unit and is available from the Miller Corporation. Tig-Rig (TM) control units 33 are situated on top of the power source 32, and likewise are available from the Miller Corporation. Water coolers 34 are located at the rear of the machine 10 and are available from the Bernard Corporation. At the left rear corner of the machine are located a plurality of gas tanks 35, which are filled with inert gas such as argon, which will provide an inert gaseous atmosphere at the welding zone to prevent oxidation and ruination of the weld. The Tig-Rig controls 33 send electric power through a tungsten electrode (not shown) centrally carried within the welding gun 31, and the tanks 35 supply argon gas through hoses 36 connected to the gun 31 as well. Here it should be noted that the welding guns 31 are stationary with respect to the machine base frame 12, thus simplifying the handling and maintenance of the welding hoses 36 and the electrodes. Accordingly, each welding head 31 is supported at a fixed vertical position along said slideway and each welding head 31 has means for welding the workpiece 30. The lower right front portion of the base frame has an L-shaped member 37 fabricated thereto, and the top of the member 37 carries an electrical box 38 having a control panel 39 as its cover. The control panel 39 serves to permit the operator to control the machine functions.
FIG. 2 illustrates the machine control panel 39, wherein a POWER ON button 40 is depressed to provide to turn the main power on to the machine 10. An EMERGENCY STOP red mushroom palm button 41 is provided, which may be easily struck to shut down all machine power. A WELD SPEED CONTROL switch 42 is a rotary potentiometer which is infinitely adjustable to set the weld speed rate, which is the traverse rate of the workpiece 11 past the stationary weld guns 31. The MODE CYCLE switch 43 is a multifunction switch having three positions: MANUAL; AUTO; and START. In the MANUAL postion, the operator uses the "JOG" selector switch 44 for controlling the directional movement of the machine slide assembly 30 during the set-up of the machine 10. When the MODE CYCLE selector switch 43 is turned to the MANUAL position, the JOG switch 44 may be turned to either UP or DOWN, to drive the machine slide assembly 30 along its vertical path. When the MODE CYCLE switch 43 is set to AUTO, the machine 10 will run in automatic operation after start of the cycle is initiated. To initate the automatic cycle, the gas from the tanks 35 is turned on from an independent valve (not shown): the MODE CYCLE selector switch 43 is turned to the START position and the machine slide assembly 30 starts upward in its travel. Release of the MODE CYCLE switch 43 causes the switch to spring-return to AUTO, and the slide assembly 30 will continue upward until a limit switch is struck, initiating firing of the weld guns 31, and upward travel will continue at a controlled weld speed until an end-of-position switch is struck, at which time the weld guns 31 will be turned off and reversal of the machine slide assembly 30 will occur, causing the assembly 30 to move downward until a lowermost load-unload position switch is actuated. At such time, the machine cycle is complete and the operator may thereby remove the finished part and insert an unfinished part to be welded. The limit switches mentioned will be discussed further in connection with FIG. 3.
Turning to FIG. 3, the welding machine is depicted with the workpiece assembly removed, showing only the structural elements. The vertical members 13, 14, at the rear corners of the base frame 12 are provided with horizontal cross bars 45, 46 carrying a drive screw bracket 47. The bracket 47 is generally formed from a main base plate 48 vertically spanning and attached to, the cross bars 45, 46, and a pair of integral end plates 49, 50, extend at 90° to the base plate 48. The end plates 49, 50, have a ball screw 51 journalled therebetween for rotation, and the ball screw 51 is restrained from axial movement. The bottom end plate 50 has a drive motor 51' secured thereto which, in this case, is an electrically driven gear motor. The brackets carry a pair of vertical slide bars 52, which are hardened and ground to a precision size and are fitted into the end plates 49, 50, at fixed, parallel, positions straddling the ball screw 51. The machine slide assembly 30 is comprised of a footstock 53 having a horizontal plate 54 or table portion, and a vertical bracket 55 secured to the plate 54. The bracket 55 is reinforced with a gusset plate 56 to maintain squareness between the horizontal and vertical members 54, 55. The vertical bracket 55 is secured to a pair of recirculating ball bushings 57 which have ball bearings therein and are available commercially from the Thompson Company and the ball bushings 57 and ball bearings thereby provide an antifriction means when fitted to the slide bars 52, by virtue of the recirculating bearing ball paths within the ball bushings 57. Thus, the bracket 55 and hence the work slide assembly 30 is supported in a cantilevered manner by the vertical slideway or slide bars 52 for vertical movement therealong, with the work slide assembly 30 having a mounting axis for the workpiece 11 disposed parallel to and spaced from said slideway for easy access thereto. Midspan between the spaced-apart ball bushings 57, the vertical member 55 is secured to a housing 58 carrying a ball nut 59, which is free to move in a vertical direction along the ball screw 51. The ball nut 59 and screw 51 are commercially available from Saginaw Ball Screw Company and contain recirculating ball elements, to provide an antifriction screw drive. Here it should be noted that other, frictional type screws might be employed, but the antifriction screws give a smooth feed and thus a very uniform weld bead or weld bead means, not probable with a jerky, rough, feed. A vertical adjusting bar 60 extends from the horizontal footstock plate 54, and the adjusting bar 60 is fitted with a plurality of horizontally-drilled holes 61 at equally spaced intervals. A headstock 62 is slidable to adjusted positions along the vertical adjusting bar 60, and may be locked in discrete locations by screws 89 to accommodate a wide range of workpiece mandrels (see FIG. 4). The headstock 62 has a U-shaped channel 63 which is slidable along the vertical adjusting bar 60 and a spacer block 64 is bolted to the U-channel 63. The spacer block 64 carries a clamping unit 65, available from the DeStaco Company, and the clamping unit 65 is an over-the-center toggle-action plunger clamp. The base bracket 66 of the clamp has a bore 67 which carries a slidable plunger 68 therein, and the plunger 68 may be retracted in the bore 67 by lifting a handle 69 which pulls through a linkage 70, thereby retracting the plunger 68. When clamping, the handle 69 is swung to the down position (shown), and the toggle linkage 70 forces the plunger 68 down in the bore 67. The plunger 68 of the clamp unit 65 carries a machine center 71 which will be described further in conjunction with FIG. 8. The machine center 71 is provided with a conical tip 72 pointing downward. An opposing machine center 73 is located on the footstock horizontal plate 54 in direct opposition to the conical tip 72 of the headstock 62. The footstock center 73 is likewise provided with a conical tip for holding a work mandrel. The machine centers 71 and 73 and their conical tips define the previously mentioned mounting axis of the slide assembly 30. A pair of extensible bellows 74, 75, surround the ball screw 51 and slide bars 52 and are located between the footstock 53 and the end plates 49, 50 of the drive screw bracket 47 to prevent contaminents from entering the antifriction elements.
Three limit switches 76, 77, 78, are provided in spaced vertical relation above one another at the right side of the machine slide assembly 30. The switches are roller type limit switches, that is, having internal contacts which may be either normally open or closed, and a rotary pin 79 serves to actuate the switch contacts. The rotary pin 79 of the switch has a lever arm 80 mounted thereto with a roller 81 at the outermost end. The rollers 81 of the limit switches are contacted by a trip dog 82 which extends from the side of the footstock 53. The switch bodies are secured to U-shaped limit switch adjusting blocks 83 which are carried on a vertical limit switch rail 84. The rail 84 is provided with a plurality of vertically spaced apart holes 85 so that the switches 76, 77, 78, may be positioned to desired levels, and fine positioning of the switch contact points relative to the machine slide assembly 30 is accomplished by slight rotary adjustment of the lever arm 80 which may be loosened and reconnected to the pin 79 of the switch. The switch-carrying rail 84 is secured to stand-offs 86, 87, welded to the horizontal cross bars 27, 46, of the base frame 12.
The machine 10 is provided with four welding guns 31, which are horizontally opposed to one another on a horizontal plane in a coordinate, X-shaped pattern. The frontmost guns 31 are angularly located in the plan view at 45° to the frontmost, operator, position. A plurality of standoffs 88 are provided on the welding support structure 24 to carry the welding guns 31.
The vertical elevational section of FIG. 4 shows the base frame 12 supporting the drive screw bracket 47, and the ball screw 51 is shown within its protective bellows 74, 75. The drive motor 52 extends from the bottom end plate 50 of the bracket 47. The ball nut 59 is carried within the nut housing 58 bolted to the vertical plate 55 of the footstock 53. The horizontal plate 54 of the footstock 53 carries the adjusting bar 60 and the headstock 62 is secured to the bar 60 by a pair of knurled-head screws 89 which may be loosened and retightened as the headstock 62 is re-positioned. The footstock center 73 and headstock center 71 are shown inserted in the conical bores of a work support mandrel 90. The work support mandrel 90 has a generally cylindrical body 91 (see FIG. 6) and a circular flange 92. The circular flange 92 supports a copper disc 93 and a vertical stack of steel stator laminations 94. A predetermined number of laminations 94 form one stator core 95, and additional copper discs 93 and alternating stator core stacks may be located on the mandrel 90. The topmost end of the mandrel 90 is formed with a threaded stud 96 (see FIG. 6) and a clamping washer 97 is located on the stud 96 and held with a nut 98 to clamp the workpiece assemblies together in unison with the work support mandrel 90. A grounding clamp 99 is secured to the footstock 53 and connected to the control unit to complete the arc welding electrical circuit.
FIG. 5 is a close-up view of a tungsten welding electrode 100 carried within the gas supply barrel 101', or torch, of the welding gun 31, and the tungsten tip 11 is sharpened to a point. The point is maintained at a fixed gage dimension (approximately 1/16 inch) from the surface of the workpiece 95 to maintain an accurate arc during the welding process. The arc fuses the laminations 94 of the stator core 95 together by burning the material into inself under a continuous melt. The machine will produce up to four welds simultaneously, or as many welds as guns can be mounted. A typical weld may be 3/16" wide and 0.010"-0.105" deep for cores 95 of thin cross section.
FIG. 6 illustrates, in perspective, the workpiece support mandrel 90 having its flange 92 and main body diameter 91 for receiving the respective pluralities of workpiece laminations 94 and the copper discs 93 which serve to space the respective stator core laminations 94. The end washer 97 and clamping nut 98 are shown to be threadably received on the mandrel stud 96.
FIG. 7 depicts a finished stator core assembly 95, wherein a plurality of lamination elements 94 are punched from thin sheets of electrical steel (generally some high silicon content iron sheeting), and uniform weld bead means or beads have been formed along the periphery of the laminations 94 to fuse the assembly together into a unitary core 95.
FIG. 8 depicts the machine center of the headstock plunger 68. The plunger 68 is shown having a threaded hole 102 in its end face 103. A center adapter 104 has a main diameter 105 extending from the plunger face 103 and a threaded stud 106 extends from the main diameter 105 and is threadably received within the hole 102 of the plunger 68. The outermost end 107 of the center adapter 104 is provided with a central bore 108 into which is received a close fitting pilot diameter 109 of a conical centering tip 72. The pilot diameter 109 has a key slot 110 machined therein, and a knurled-head set screw 111 is threadably received transversely through the center adapter 104, extending into the key slot 110 of the pilot diameter 109. A very stiff backup spring 112, having a preload in the range of 600 pounds, is received in the bore 108 of the center adapter 104, and serves to bias the center tip 72 to an extreme downward position. The extreme stiffness of the spring 112 causes the headstock center assembly to be essentially a rigid unit, yet some compliance of the center tip 72 is permissible when the tip 72 is thrust down into mandrels 90 of slightly varying length. Thus, differing mandrels 90 can still be clamped tightly because of the compliance of the center tip 72.
The perspective view of FIG. 9 illustrates the universal "gimbal-type" mounting provided for holding the welding guns 31. The base frame weld support member 24 is provided with a standoff 88 which is angled and carries a vertical support plate 113. The support plate 113 has a horizontal pin 114 onto which is received an adapter block 115. The adapter block 115 has a horizontal hole 116 and a vertical hole 117 therethrough and saw slots 118 and clamping screws 119 are provided to secure the block 115 in position. The vertical hole 117 through the adapter block 115 receives the vertical pin 120 of a welding gun body 121. The welding gun body is comprised of two semicircular housing parts 122, 123, which are clamped together by screws 123' around the main barrel diameter 124 of the welding gun torch 101. The semicircular housing parts 122, 123 of the welding gun body 121 have a manually rotatable gear 125 located therewithin a bore 126, and adjusting knob 127 is attached to a rod 128 which is keyed into the gear 125. The gear 125 is in mesh with a linear rack 129 located on the welding gun torch barrel 124. Thus, when the gun assembly 31 is clamped together, the knob 127 may be rotated manually to advance retract the welding gun torch 101 in the direction of the double-ended arrow to facilitate set-up of the guns 31 and maintain the arc gap. The adjusting knob 127 and rod 128 are held into engagement with the entrapped gear 125 by a screw 130 and washer 131 provided through the topmost end of the semicircular housing part 122. A graduated scale 131 is provided around the support pin 120 so that angular positioning of the welding torch barrel 124 may be easily facilitated.
Referring to FIG. 10, the relative positions of the slide assembly 30 and limit switches 76, 77, 78 are shown. The lowermost switch 76 is used to signify the end of cycle and is the position at which the loading and unloading of the workpiece mandrel 90 is performed. The next switch 77 is utilized to start the welding operation as the machine slide assembly 30 traverses upward with an unfinished part. The topmost switch 78 is used to signify the end of the welding operation and to reverse the machine slide assembly movement down to the unload position.
In operation, therefore, the operator inserts a mandrel 90 into the machine 10 and clamps it with the headstock clamp unit 65 while the work slide assembly 30 is in the downmost position whereby the mandrel 90 and thus workpiece 11 are disposed with their common central longitudinal axes coinciding with the previously described mounting axis and such axes and axis are disposed parallel and in spaced side-by-side relation with said slideway defined by bars 52. Referring to FIG. 2, the operator sets the desired WELD SPEED, and places the MODE CYCLE select switch 43 in AUTO. To commence the cycle, the MODE CYCLE switch 43 is rotated to the START position and upward slide movement will occur. The operator then releases the MODE CYCLE switch 43, which returns to the AUTO position as the slide undergoes movement in the vertical direction. The switch dog 83, carried by the machine slide assembly 30, strikes the welding operation start switch 77, and power is provided to the welding guns 31 by the commercial power units 32, 33, of FIG. 1. The commercial TIG-RIG power units are provided with their own "ELECTRO-SLOPE" (TM) control unit which gradually applies the voltage and amperage to the leading edge of the workpiece to initially start the bead formation and thereby prevent breakdown of the corners of the part. As the slide movement continues, the voltage and current is increased to a predetermined level thereby forming the fused bead on the workpiece laminations 94 in a uniform amount. The slide assembly 30 continues in its upward travel until such point as it contacts the uppermost, "end-of-weld", limit switch 78 and a similar deceleration of the weld voltage and current occurs before power is shut off to the welding guns 31 by the commercial units. At the uppermost point, the drive motor 52 reverses its direction, thereby retracting the slide downwardly while the welding guns 31 are turned off. In its downmost movement, the switch dog 83 contacts and over travels the start switch roller, continuing downward until the "down" stop switch 76 is contacted and the cycle is complete.
The plan view of FIG. 11 shows the relation of the four welding guns 31 to one another, and to the workpiece assembly 95. The ball screw 51 is shown captivated in the top end plate 49 of the drive screw bracket 48, and is straddled by the slide bars 52 which are likewise captivated in the drive screw bracket 48.
As a first alternate embodiment, it may be appreciated by those skilled in the art that the headstock 62 may be removed from the machine and the footstock 53 can be provided with an expanding arbor workholding chuck with a valve-operated fluid clamp. By such arrangement, production loading of the laminations 94 can be accomplished individually at the machine site rather than on mandrels 90 off the machine 10.
As a second alternate embodiment, those skilled in the art will appreciate that the welding guns 31 are individually set to a fixed radial distance from the part and therefore, a variety of cross-sectional shapes of cores 95 may be welded. For example: square, hexagonal and octagonal cross-sections. Of course, it is seen that the machine 10 is configured for straight-sided parts, but motorized means could be attached to the rod 128 and knob 127 of the gun 31 to radially position the gun barrel 101 in relation to axial movement of the workpiece, therefore permitting the welding of cores and the like.
FIGS. 12(a) & (b) depict a ladder wiring diagram for the machine, embodying relay logic. The power lines L1 and L2 carry current at 120 VAC, 60 HZ, 1 PH. In the starting, or "home", position, the slide assembly is in the lowermost position, holding the NO (normally open) contacts of the lower limit switch LS1 "closed". When the POWER ON switch S1 is momentarily closed, control relay CR1 is energized through that switch, lighting the "power on" light and immediately line L1 is maintained through the energized NO contacts of CR1 and the NC (normally closed) EMERGENCY STOP switch, S2. Switch S1 may now be released since the latch circuit through the NO contacts of relay CR1 through the MODE CYCLE switch, S4 A&B (tied together) in the AUTO position, closing the (NO) CR2 contacts in the weld gun circuits of FIG. 12(a).
To manually move the normally de-energized drive motor, the MODE CYCLE switch S4 is moved to the MANUAL position, energizing latching relays LR1L and LR2R through JOG switch S3 A&B (tied together), and closing NO contacts LR1L in the cross-over legs of the drive motor circuit and the CR3 line (CR3 contacts remain open).
Next, the JOG switch S3 A&B may be turned, for example, to the "DOWN" position. LR1L is maintained in the energized state. CR3 is energized through the JOG switch S3(B), closing NO contacts CR3 in the drive motor circuit, causing the drive motor to rotate in a first direction. When the JOG switch S3(A) is switched to the UP position, latching relay LR1R is energized, closing the LR1R contacts in the drive motor circuit. Control relay CR3 is energized through contacts LR1R and JOG switch S3(B), thus reversing the direction of the drive motor.
To begin an automatic cycle, the MODE CYCLE switch S4 A&B is first held to the START position and then released to the AUTO position. LR1R is first energized, then as the switch is released to the AUTO position, CR3 is energized through latched contacts LR1R. Closed contacts CR3 and LR1R in the drive motor circuit cause the drive motor to rotate, driving the slide assembly upward. Continuing upward, the slide assembly closes NO limit switch LS2, energizing latching relay LR2L. Time delay relay TD1 is energized (closing contacts TD1), as well as TD4 and TD5, to start the arc welding guns. Control relay CR8 is energized through NC contacts TD4, completing the weld gun circuit in FIG. 12(a). At the top of the slide assembly travel, NO limit switch LS3 is picked up (closed), energizing the STOPDELAY TIME DELAY RELAY, TD2. At this time, the DOWNSCOPE, ARC STOP, and PAUSE time delay relays TD6, TD7, & TD3 are energized to end the weld. The slide assembly may then be manually powered DOWN.
When the EMERGENCY STOP switch S2 is depreseed, at any time, control relay CR1 is de-energized, opening the NO contacts in line L1, halting all machine operation.
Other details of the welding ciruit are omitted as being well-known in the art and commercially available.
While the invention has been shown in conjunction with a specific embodiment, it is not intended to limit the invention to such specific embodiment, but rather the invention extends to all such designs and modifications as come within the scope of the appended claims.
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An automatic welding machine for arc-welding stator core laminations is disclosed. The machine carries singular or plural workpieces which are fixtured on a vertical slideway. A slide moves past relatively stationary welding guns which are independently adjusted and independently activated for the weld process. The workpieces may be indexed for desired weld spacing. In one embodiment the indexing may be manual or power actuated. In another embodiment the guns may be varied as to radial position as the workpiece is moved, to weld non-constant cross-sectioned parts.
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BACKGROUND
The present invention relates to the unloading of bulk bags used as containers for dry or moist particulate materials. The present invention more particularly relates to the unloading of bulk bag containers fabricated from cloth like material, such as woven polyester material, which is usually sewn in a cubical configuration.
Bulk bags made of heavy cloth material have been known in the art for sometime. It has also been known to provide the bag with heavy corner straps which support the bag when it is hung in a tower like support frame. The opposite end of the bag typically has an outlet spout which is aligned with the discharge unit of a receptacle, for example a conveyer, hopper or the like, through which the material is intended to be discharged.
To discharge the bag, the bag is hung in the support frame and material flows via gravity through the spout to the discharge unit. It is a characteristic of some particulate materials contained in a bag to resist or stop flowing out of the spout when the material remaining in the bag reaches the material's angle of repose or bridges over the spout. Since the bottom of the bag, where it is attached to the spout, is typically not at angle greater than the material's angle of repose, not all of the material will be discharged through the spout by gravity.
To address such, U.S. Pat. No. 5,184,759, commonly assigned with the present invention, discloses an apparatus which attaches to the spout and elongates the bag as material flows from the bag. As a result, the bottom of the bag forms more of a funnel shape, with the walls at an angle greater than the material's angle of repose, and the material flows more freely through the spout.
While the apparatus disclosed in U.S. Pat. No. 5,184,759 has proven successful at promoting freer flow from bulk bags, the manner in which the bag spout is attached to the moveable spout member has not always been the most desirable. With that devise, material may build up about the outside portion of the moveable spout. When the spout is released, the built-up material, particularly if it is a powdery material, may spill and contaminate the work environment.
U.S. Pat. No. 5,341,959 issued to Ellis discloses a means of connecting a bag spout to a moveable spout member with an internal securing configuration. However, this configuration is complex to manufacture and difficult to use. Due to the internal connection, an operator may have insufficient clearance to effectuate a proper connection inside the moveable spout member, particularly if the bag spout is short.
Accordingly, there is a need for a bulk bag unloading apparatus which includes a simpler, cleaner attachment arrangement.
SUMMARY
The present invention relates to a bulk bag unloading station wherein a bulk bag is suspended above a discharge receptacle. An assembly is provided for securing a spout extending from the bag to a discharge tube. The assembly comprises a clamp ring which defines a channel configured to receive the free edge of the tube therein and define a bag spout securing area. An actuator assembly is moveable between a first position where the clamp ring is spaced from the free edge and a second position where it overlies the tube free edge. In a preferred embodiment of the invention, the discharge tube is moveably mounted such that it extends the bag spout as the bag empties.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevation view of a bulk bag unloading station incorporating the present invention.
FIG. 2 is a top plan view of the preferred embodiment of the spout securing apparatus of the present invention.
FIG. 3 is a side elevation view of the spout securing apparatus of FIG. 2 .
FIG. 4 is a partial cross-sectional view of a preferred moveable spout member of the present invention.
FIG. 5 is a top plan view of a clamp ring useable with the preferred spout member of the present invention.
FIG. 6 is a cross-sectional view along the line 6 — 6 in FIG. 5 .
FIG. 7 is a side view and FIG. 8 is a front elevation of a preferred clamp actuator, useable with the present invention, in an extended position.
FIG. 9 is a side view and FIG. 10 is a front elevation of the preferred clamp actuator in transition.
FIG. 11 is a side view and FIG. 12 is a front elevation of the preferred clamp actuator in a closed position.
FIG. 13 is a partial cross-sectional view of an alternate embodiment of the preferred moveable spout member of the present invention.
FIG. 14 is a top plan view of a clamp ring useable with the alternate embodiment of the present invention.
FIG. 15 is a cross-sectional view along the line 15 — 15 in FIG. 14 .
FIGS. 16, 17 and 18 A progressively illustrate the clamping of a bag spout to the moveable spout member of FIG. 4 .
FIG. 18B is an enlarged view of the indicated portion of FIG. 18A showing the clamped position of the bag spout.
FIGS. 19, 20 and 21 A progressively illustrate the clamping of a bag spout to the moveable spout member of FIG. 7 .
FIG. 21B is an enlarged view of the indicated portion of FIG. 21A showing the clamped position of the bag spout.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The preferred embodiments of the present invention will be described with reference to the drawing figures where like numerals represent like elements throughout.
An exemplary bulk bag unloading station 5 incorporating the present invention is shown in FIG. 1 . The bulk bag unloading station 5 generally includes a support frame 6 from which a bulk bag 2 is suspended by the suspension assembly 8 . A hoist mechanism is illustrated, but other suspension assemblies may be used. The suspension assembly forms no part of the invention. A discharge receptacle 10 , for example a hopper, is positioned within the support frame beneath and in general alignment with the bulk bag 2 . A spout adapter 20 is positioned between the bulk bag spout 4 and the discharge receptacle 10 .
The preferred embodiments of the spout adapter 20 will be described in more detail with reference to FIGS. 2-15. Referring to FIGS. 2 and 3, the spout adapter 20 generally comprises a moveable discharge tube spout member 30 , a clamp ring assembly 50 and a control assembly 80 . The preferred control assembly 80 includes vertical mounting bracket 82 secured on the support frame 6 . Trolley assembly 86 is mounted to and moveable along the vertical mounting bracket 82 by the plurality of roller assemblies 88 . Opposed mounts 84 and 100 extend from the vertical mounting bracket 82 and the trolley assembly 86 , respectively. A fluid actuator 96 , including an extendable rod 98 , is mounted between the opposed mounts 84 and 100 .
The support frame 90 extends from the trolley assembly 86 toward the moveable spout member 30 . In the preferred embodiment, the support frame 90 includes a cross-bar 92 which supports a pair of opposed brackets 94 that connect to the moveable spout member 30 . The cross-bar 92 and opposed brackets 94 are preferred as they provide a balanced attachment for the spout member 30 about the center-line thereof, however, other attachment means may be utilized.
Referring to FIG. 3, movement of the moveable spout member 30 corresponds to movement of the actuator rod 98 as translated through the trolley assembly 86 . Downward movement of the moveable spout member 30 may occur either by positive actuation of the fluid actuator 96 to drive the rod 98 downward or by gravity.
Referring to FIG. 4, a first embodiment of the moveable spout member 30 is illustrated. The moveable spout member 30 preferably comprises a cylindrical tube 32 having an inlet end 36 and an outlet end 38 and connected by the brackets 94 , shown in phantom, to the control assembly 80 (not shown). The tube 32 is preferably manufactured from sheet metal, plastic or the like and is preferably cylindrical to complement the most common bag spout 4 . Transition tube 34 extends from the outlet end 38 of the cylindrical tube 32 and communicates with the discharge receptacle 10 . In the preferred embodiment, the transition tube 34 , manufactured from a flexible, accordion folded material, is secured at opposed ends thereof to the cylindrical tube 32 and the discharge receptacle 10 . The preferred material allows the transition tube 34 to expand and contract uniformly in response to movement of the cylindrical tube 32 . Alternatively, the end of the transition tube 34 addressing the receptacle may be unattached, similar to the means described in U.S. Pat. No. 5,184,759.
Referring to FIGS. 5 and 6, the preferred clamp ring 52 is illustrated. Clamp ring 52 includes a ring or plate 54 which defines an aperture 56 having a diameter less than or equal to the inside diameter of the tube 32 . A pair of spaced walls 58 , 60 depend from the plate 54 to define a channel 62 configured to receive an upper edge of the spout tube 32 . See FIG. 18. A gasket 64 , manufactured from rubber or some other pliable material, is preferably positioned within the channel 62 adjacent to the plate 54 . A pair of opposed support brackets 66 extend from the plate 54 .
Referring to FIGS. 2 and 3, the moveable spout member 30 and the clamp ring 52 are preferably interconnected by a pair of clamp actuators 70 . The preferred clamp actuators 70 will be described with reference to FIGS. 7-12. Each preferred clamp actuator 70 includes a mounting bracket 71 which is securable either directly to the spout tube 32 or to the brackets 94 . An apertured guide block 72 is attached proximate the top of the mounting bracket 71 and a pair of pivot mounts 69 extend from a lower portion of the mounting bracket 71 . A rod 73 extends through the aperture in the guide block 72 for slidable movement therethrough. A first end 73 a of the rod 73 is configured for connection with a respective support bracket 66 on the clamp ring 52 . In the preferred embodiment, the rod end 73 a is threaded and extends through an aperture 68 in the support bracket 66 and is secured thereto with bolts (not shown) or the like. Other connection arrangements may also be utilized. The other end 73 b of the rod 73 is configured for pivotal connection to a first pair of links 75 via pivot pin 74 or the like. The first pair of pivot links 75 are in turn pivotally connected to link 77 via pivot pin 76 or the like. Link 77 is pivotally connected to the mounting bracket mounts 69 via pivot point 78 . A handle 79 is preferably secured to link.
In an initial position, as shown in FIGS. 10 and 11, the links 75 and 77 are in substantial vertical alignment with the rod 73 is in an extended position. This position maintains the clamp ring 52 spaced from the moveable spout member 30 such that the bag spout 4 can be passed through the aperture 56 and positioned about the spout tube 32 . It is preferable that the links 75 and 77 are not in complete alignment, but instead slightly offset toward the mounting bracket 71 (See FIG. 10 ). With such an alignment, the likelihood that the links 75 , 77 will inadvertently rotate and lower the clamp ring 52 is reduced. Referring to FIGS. 12 and 13, to lower the clamp ring 52 , the handle 79 is moved along an arcuate path whereby link 77 rotates about pivot pin 78 and correspondingly, through pivot point 76 , links 75 rotate downward thereby, through pivot point 74 , retracting the rod 73 . Referring to FIGS. 14 and 15, the handle 79 is moved until link 77 is substantially horizontal and the links 75 are at an approximately forty-five degree (45°) angle thereto. The further downward travel of links 75 further retracts the rod 73 . The links 75 and 77 are configured such that the stroke of the rod 73 causes engagement of the clamp ring 52 with the spout tube 32 and the linkage is effectively locked with the clamp ring 52 in a closed position. To release the clamp ring 52 , the handle 79 is rotated back along its arcuate path. Other actuation means, for example a fluid actuator, may also be used.
Referring to FIG. 13, an alternative embodiment of the moveable spout member 130 is shown. Moveable spout member 130 includes an external tube 134 mounted about tube 32 by brackets 136 or the like. The control assembly 80 (not shown) is secured to the external tube 134 in a manner similar to the previous embodiment. Transition tube 34 extends from, and about, both tubes 32 and 134 . External tube 134 includes an aperture 138 through which a vacuum apparatus 140 may be connected. The vacuum apparatus 140 extrudes fine particulate material which may attempt to escape the spout member 130 .
Referring to FIGS. 14 and 15, clamp ring 152 is similar to clamp ring 52 and includes a plate 54 with an aperture 56 therethrough. Two pairs of spaced walls 58 , 60 and 158 , 160 depend from the plate 54 to define two channels 62 and 162 . One channel 62 is configured to receive an upper edge of the spout tube 32 and the other channel 162 is configured to receive an upper edge of the external tube 134 . A gasket 64 is preferably positioned in each of the channels 62 and 162 . Again, a pair of opposed support brackets 66 extend from the plate 54 for interconnection to the actuators 70 .
Having described the preferred components of the system, its operation will be further described with reference to FIGS. 16, 17 , 18 A, 18 B, 19 , 20 , 21 A and 21 B.
Referring to FIG. 16, the spout adapter 20 is set in an initial position with the ring clamp 52 aligned above the moveable spout member 30 . A bulk bag is positioned with its spout 4 aligned with the aperture 56 in the clamp ring 52 . Referring to FIG. 17, the bag spout 4 is passed through the aperture 56 and positioned about the spout tube 32 without any extraneous preparation of the bag spout 4 . Referring to FIG. 18A, the clamp ring 52 is lowered via the clamp actuators (not shown) until the upper edge of the tube 32 seats within the clamp ring channel 62 . The bag spout 4 is thereby secured between the tube 32 and the clamp ring channel 62 , as shown in detail in FIG. 18 B. The gasket 64 provides resiliency to prevent excessive pinching of the bag spout 4 and to provide a more thorough seal. As can be seen in FIGS. 18A and 18B, the bag spout 4 is effectively sealed to the moveable spout member 30 with an unobstructed material path defined.
Referring to FIGS. 19, 20 , 21 A and 21 B operation of the double wall embodiment is illustrated. As shown in FIG. 20, the bag spout 4 is again passed through the clamp ring aperture 56 and positioned about the spout tube 32 . The brackets 136 are preferably positioned such that they do not interfere with the bag spout 4 . Referring to FIG. 21A, the clamp ring 52 is lowered via the clamp actuators (not shown) until the upper edge of the tube 32 seats within clamp ring channel 62 and the upper edge of the external tube 134 seats within clamp ring channel 162 . The bag spout 4 is thereby secured between the tube 32 and the clamp ring channel 62 and the external tube 134 seals against the clamp ring 152 , as shown in detail in FIG. 21 B. With the external tube 134 sealed by the clamp ring 152 , any particulate remaining in the moveable spout member 130 can be extruded through the vacuum apparatus 140 .
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A bulk bag unloading station wherein a bulk bag is suspended above a discharge receptacle. An assembly is provided for securing a spout extending from the bag to a discharge tube. The assembly comprises a clamp ring which defines a channel configured to receive the free edge of the tube therein. An actuator assembly is moveable between a first position where the clamp ring is spaced from the free edge and a second position where it overlies the tube free edge.
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FIELD OF THE INVENTION
[0001] The present invention relates to methods comprising pyrolyzing biomass (e.g., a lignocellulosic material) and recovering acetic acid, for example at a purity level of at least about 95% by weight, from the pyrolysis reactor effluent. Conditions for the separation of this effluent, for example prior to downstream hydroprocessing of a major portion of this effluent, may be selected to facilitate acetic acid purification and/or enhance recovery.
DESCRIPTION OF RELATED ART
[0002] Acetic acid is a high volume chemical that is utilized as a reactant, solvent, or catalyst in numerous processes. For example, acetic acid is converted according to known reaction pathways to vinyl acetate monomer (VAM), which is polymerized to form latex emulsion resins for paints and adhesives. Also, fibers and plastics are manufactured from acetic anhydride, which is another conversion product of acetic acid. An important industrial use for acetic acid as a solvent is in the production of purified terephthalic acid (PTA) by the oxidation of para-xylene with air in solution. PTA is used principally as a precursor of polyethylene terephthalate (PET) for clothing and plastic bottle manufacture, as well as other high-performance multi-purpose plastics such as polybutylene terephthalate (PBT) and polytrimethylene terephthalate (PTT). Global consumption of PTA is projected to exceed 50.5 million metric tons by the end of the year 2012, based on a report by Global Industry Analysts, Inc.
[0003] In the case of PTA production, some of the acetic acid solvent is oxidized to CO 2 as an unwanted byproduct. This contributes not only to the overall consumption that must be replaced through the addition of make-up acetic acid, but also to the greenhouse gas (GHG) emissions associated with the PTA production process. In view of its relatively high cost, an alternative source of less expensive acetic acid would be highly desirable. Additionally, a source of acetic acid based on renewable rather than sequestered (e.g., fossil fuel) carbon would reduce the carbon footprint of PTA production, in addition to numerous other processes utilizing the acetic acid for various end uses. Currently, the most prevalent route to acetic acid manufacture is based on the carbonylation of methanol, which is most often derived from the methane of a fossil fuel, namely natural gas.
[0004] Environmental concerns over emissions of such fossil-derived carbon in GHGs have led to an increasing emphasis on renewable energy sources. Wood and other forms of biomass including agricultural and forestry residues are examples of renewable feedstocks, which are currently being considered as a basis for the production of liquid fuels. Energy from biomass based on energy crops such as short rotation forestry, for example, can contribute significantly towards the objectives of the Kyoto Agreement in reducing greenhouse gas (GHG) emissions.
[0005] Pyrolysis is considered a promising route for achieving this objective of converting biomass feedstocks to liquid fuels, including transportation fuel and heating oil. Pyrolysis refers to thermal decomposition in the substantial absence of oxygen (or in the presence of significantly less oxygen than required for complete combustion). Initial attempts to obtain useful oils from biomass pyrolysis yielded predominantly an equilibrium product slate (i.e., the products of “slow pyrolysis”). In addition to the desired liquid product, roughly equal proportions of non-reactive solids (char and ash) and non-condensible gases were obtained as unwanted byproducts. More recently, however, significantly improved yields of primary, non-equilibrium liquids and gases (including valuable chemicals, chemical intermediates, petrochemicals, and fuels) have been obtained from carbonaceous feedstocks through fast (rapid or flash) pyrolysis at the expense of undesirable, slow pyrolysis products.
[0006] Fast pyrolysis refers generally to technologies involving rapid heat transfer to the biomass feedstock, which is maintained at a relatively high temperature for a very short time. The temperature of the primary pyrolysis products is then rapidly reduced before chemical equilibrium is achieved. The fast cooling therefore prevents the valuable reaction intermediates, formed by depolymerization and fragmentation of the biomass building blocks, namely cellulose, hemicellulose, and lignin, from degrading to non-reactive, low-value final products. A number of fast pyrolysis processes are described in U.S. Pat. No. 5,961,786; Canadian Patent Application 536,549; and by Bridgwater, A. V., “Biomass Fast Pyrolysis,” Review paper BIBLID: 0354-9836, 8 (2004), 2, 21-49. Fast pyrolysis processes include Rapid Thermal Processing (RTP), in which an inert or catalytic solid particulate is used to carry and transfer heat to the feedstock. RTP has been commercialized and operated with very favorable yields (55-80% by weight, depending on the biomass feedstock) of raw pyrolysis oil.
[0007] The raw pyrolysis oil typically contains a relatively high oxygen content and relatively low energy content, compared to petroleum derived liquid fuel components. Other properties of this oil (e.g., high acidity and viscosity) render it generally unusable, in any appreciable proportion, as a component of a transportation fuel composition. Significant upgrading, however, may be achieved by hydroprocessing of the raw pyrolysis oil. Despite recent progress in the area of biofuel development, however, there remains a need in the art for the production of chemicals such as acetic acid from renewable resources, in a manner that achieves high purity and recovery of the desired compound. The fossil-derived GHG emissions associated with number of end products, including polymers, can be significantly reduced if renewable carbon is used in the generation of the associated chemical solvents and reactants consumed in their manufacturing processes.
SUMMARY OF THE INVENTION
[0008] Aspects of the present invention are associated with the discovery of methods for producing, from renewable carbon sources, acetic acid in a manner that is generally less expensive than conventional routes (e.g., methanol carbonylation) based on fossil-derived carbon sources. These methods address the separation and recovery of acetic acid as a substantial product of biomass pyrolysis. In particular, as much as 5% by weight or more of the pyrolysis product (or pyrolysis reactor effluent) can be acetic acid, depending on the biomass feedstock and pyrolysis conditions. For a given commercial biomass pyrolysis unit, this yield can represent a significant quantity, for use in a commercial chemical application such as purified terephthalic acid (PTA) production. According to some embodiments, pyrolysis conditions and/or flow schemes advantageously improve the recovery of acetic acid for a given purity level.
[0009] Representative pyrolysis processes adapted for acetic acid production have at least two stages for separation/condensation of the pyrolysis reactor effluent. A first separation stage condenses an aqueous phase comprising, in addition to water, acetic acid as well as other oxygen-containing compounds (oxygenates) having higher and lower boiling points relative to acetic acid. These include cellobiose and relatively smaller amounts of formic acid, acetaldehyde, formaldehyde, acetone, hydroxyacetone, furfural, and trace amounts of oxygenates having a higher boiling point than furfural. According to various embodiments of the invention, operating conditions of the first stage are adjusted to increase the proportion of acetic acid, present in the pyrolysis reactor effluent, in either the condensed aqueous phase or the overhead vapor exiting the first stage. In case of vaporized acetic acid exiting the first separation stage, this may be purified from the overhead vapor by distillation, for example after first removing, in a second separation stage, light components by flash separation. According to some embodiments, this flash separation may be used to obtain a second stage bottoms product enriched in acetic acid relative to the first stage overhead product.
[0010] Depending on the quality (i.e., purity) of acetic acid required for a particular application and/or the maximum tolerable amounts of certain impurities (e.g., water), distillation may be combined with further downstream purification/separation steps including selective adsorption over a fixed or moving bed of solid adsorbent. In yet further embodiments, distillation may be combined with upstream purification/separation steps, for example membrane separation to remove water, thereby significantly decreasing the amount of material processed in the distillation column and the overall energy costs required to achieve a given combination of acetic acid purity and recovery. In general, membrane separation may be advantageous for separating the significant quantity of water present with acetic acid in the second separation stage bottoms product in acetic acid production methods described herein.
[0011] Embodiments of the invention are therefore directed to methods for producing acetic acid comprising pyrolyzing biomass (e.g., lignocellulosic material such as wood, corn stover, and/or switch grass) to provide a pyrolysis reactor effluent. The methods also comprise separating at least a portion of the pyrolysis reactor effluent in a first separation stage (e.g., a quenching tower that includes quench liquid recycle) to provide first stage overhead and first stage bottoms products. The methods further comprise recovering the acetic acid from the first stage overhead product or the first stage bottoms product. Recovery can involve various processing steps, some or all of which may enrich a recovered intermediate or end product (e.g., a purified acetic acid product) in acetic acid and deplete the recovered product in other compounds (e.g., water and other oxygenates) produced from pyrolysis.
[0012] Other embodiments of the invention are directed to methods for making purified terephthalic acid (PTA) comprising oxidizing para-xylene in the presence of a solvent comprising acetic acid produced according to methods described herein. Representative values for the acetic acid solvent make-up rate, to compensate for PTA production losses (e.g., due to oxidation to CO 2 ), are generally in the range from about 1% to about 6%, and typically from about 2.5% to about 4.5%, by weight relative to the PTA production rate (i.e., kg/hr of acetic acid make-up per 100 kg/hr of PTA produced).
[0013] Acetic acid as well as final products such as PTA (made using acetic acid as a reactant, solvent, or catalyst) may therefore be derived, using methods described herein, either partly or completely from renewable sources of carbon (e.g., biomass). As a result, the acetic acid and final products exhibit reduced greenhouse gas (GHG) emissions, based on a lifecycle assessment (LCA) from the time of cultivation of feedstocks (in the case of plant materials) required to produce the acetic acid, up to and including the ultimate disposal of the acetic acid or final product by the end user. As discussed above, CO 2 emissions resulting from the oxidation of pyrolysis-derived acetic acid (e.g., in PTA manufacturing processes) are not reported in the lifecycle GHG emission value for acetic acid or products associated with its consumption, according to U.S. government GHG emission accounting practices, as carbon derived from biomass is renewed over a very short time frame compared to carbon derived from fossil fuels (e.g., coal, natural gas, and petroleum). LCA values of emissions in terms of CO 2 equivalents can be calculated, for example, using SimaPro 7.1 software and Intergovernmental Panel on Climate Change (IPCC) GWP 100a methodologies.
[0014] Further embodiments of the invention are directed to purified acetic acid products derived from pyrolysis and comprising substantially pure acetic acid, meaning that the products comprise acetic acid in an amount of generally at least about 95% (e.g., from about 95% to about 99.9%) by weight, typically at least about 97% (e.g., from about 97% to about 99.7%) by weight, and often at least about 99% (e.g., from about 99% to about 99.5%) by weight.
[0015] These and other embodiments and aspects relating to the present invention are apparent from the following Detailed Description.
BRIEF DESCRIPTION OF THE DRAWING
[0016] The FIGURE depicts a representative process for the production of acetic acid from the pyrolysis of biomass, according to aspects of the invention.
[0017] FIG. 1 should be understood to present an illustration of the invention and/or principles involved. In order to facilitate explanation and understanding, a simplified process flowscheme is used, in which the equipment shown is not necessary drawn to scale. Details including pumps, heaters and heat exchangers, valves, instrumentation, and other items not essential to the understanding of the invention are not shown. As is readily apparent to one of skill in the art having knowledge of the present disclosure, methods for producing acetic acid according to various other embodiments of the invention, will have configurations and components determined, in part, by their specific use.
DETAILED DESCRIPTION
[0018] The FIGURE depicts a representative method for producing acetic acid (CH 3 COOH) having some or all of its carbon derived from renewable sources such as biomass. This method, as well as methods according to the present invention in general, involves pyrolyzing biomass. The biomass subjected to pyrolysis in an oxygen depleted environment, for example using Rapid Thermal Processing (RTP), can be any plant material, or mixture of plant materials, including a hardwood (e.g., whitewood), a softwood, or a hardwood or softwood bark. Energy crops, or otherwise agricultural residues (e.g., logging residues) or other types of plant wastes or plant-derived wastes, may also be used as plant materials. Specific exemplary plant materials include corn fiber, corn stover, and sugar cane bagasse, in addition to “on-purpose” energy crops such as switchgrass, miscanthus, and algae. Short rotation forestry products, as energy crops, include alder, ash, southern beech, birch, eucalyptus, poplar, willow, paper mulberry, Australian blackwood, sycamore, and varieties of paulownia elongate. Other examples of suitable biomass include organic waste materials, such as waste paper and construction, demolition, and municipal wastes. In general, acetic acid may be produced, according to methods described herein, by pyrolyzing any feedstock comprising lignocellulosic biomass. Because the biomass feedstocks are composed of the same building blocks, namely cellulose, hemi-cellulose, and lignin, mixtures of these various feedstocks and changing feedstock compositions, may be used generally without difficulty in the production of raw pyrolysis oils from these various feedstocks.
[0019] According to the embodiment depicted in the FIGURE, a feedstock comprising biomass 10 is introduced to pyrolysis reactor (pyrolyzer) 100 together with pyrolysis gas 12 that is shown as a single stream in the FIGURE but may, according to some embodiments, include two or more gas streams such as (i) oxygen-containing gas that partially combusts biomass 10 in pyrolysis reactor 100 and (ii) fluidizing gas that fluidizes small solid particles of biomass 10 . Both the fluidizing gas and oxygen-containing gas may be obtained at least in part from the recycling of products from other unit operations in the overall process such as (i) a combustor (not shown) of char that is separated from particle-laden pyrolysis product 14 or (ii) second separation stage 400 that provides overhead product 16 containing non-condensible gases including methane, CO, CO 2 , H 2 , and N 2 . Prior to entering pyrolysis reactor 100 , biomass 10 normally undergoes pretreatment steps including drying and grinding to provide the moisture levels and particle sizes desired for pyrolysis, and especially using RTP.
[0020] Particle-laden pyrolysis product 14 undergoes a preliminary gas/solids separation using cyclone separator 200 to remove solid byproduct 18 comprising char and sand, the former often used as a combustion source to generate at least some of the heat required for pyrolysis. The resulting pyrolysis reactor effluent 20 is essentially free of solids and generally contains a mixture of valuable compounds obtained from depolymerization and fragmentation of cellulose, hemicellulose, and lignin. The oxygen content of pyrolysis reactor effluent 20 is generally from about 20% to about 45%, and typically from about 30% to about 35%, by weight, based on the percentage of atomic oxygen in these compounds and their overall percentages in pyrolysis reactor effluent 20 . Representative compounds include organic oxygenates such as hydroxyaldehydes (e.g., hydroxyacetal), hydroxyketones (e.g., hydroxyacetone), sugars (e.g., cellobiose), carboxylic acids, phenolics, and phenolic oligomers as well as dissolved water.
[0021] Although a pourable and transportable liquid fuel, the raw pyrolysis oil that is normally recovered mainly from pyrolysis reactor effluent 20 , optionally following conventional processing steps, has only about 55-60% of the energy content of crude oil-based fuel oils. Representative values of the energy content are in the range from about 19.0 MJ/liter (69,800 BTU/gal) to about 25.0 MJ/liter (91,800 BTU/gal). Moreover, this raw product is often corrosive and exhibits chemical instability. Hydroprocessing of this pyrolysis oil is therefore recognized as beneficial in terms of reducing its oxygen content and increasing its stability, thereby rendering the hydroprocessed product more suitable for blending in fuels, such as petroleum-derived gasoline. Hydroprocessing involves contacting the pyrolysis oil with hydrogen and in the presence of a suitable catalyst, generally under conditions sufficient to convert a large proportion of the organic oxygen in the raw pyrolysis oil to CO, CO 2 , and water that are removed. After hydroprocessing, the resulting hydroprocessed pyrolysis oil has an oxygen content that is generally reduced from about 90% to about 99.9%, relative to the oxygen content of the raw pyrolysis oil.
[0022] Aspects of the present invention are associated with improving the overall value of the pyrolysis-derived product yield by recovering important compounds, and especially acetic acid, in significant quantities from biomass pyrolysis. Importantly, these compounds, often oxygenates, may be separated from the raw pyrolysis oil that is conventionally hydroprocessed, thereby preventing their conversion (i.e., deoxygenation) to lower value hydrocarbons. According to some embodiments of the invention, conditions for downstream processing of pyrolysis reactor effluent 20 , for example in first and second separation stages 300 , 400 (e.g., condensation stages) are selected to facilitate recovery and/or purification of the desired compound. Although the following discussion is directed to an exemplary embodiment of the invention in which acetic acid is recovered and/or purified, those skilled in the art and having knowledge of the present disclosure will appreciate that other compounds (e.g., furfural or hydroxyacetone) can likewise be separated and further purified as a desired product of biomass pyrolysis.
[0023] According to exemplary methods in which pyrolysis is integrated with hydroprocessing (not shown in the FIGURE) for the production of biofuels, generally at least about 50% by weight, typically at least about 75% by weight, and often at least about 90% by weight, of the pyrolysis reactor effluent is subjected to hydroprocessing, while minor amounts of this effluent are separated for the recovery/purification of acetic acid and/or other desired compounds. Although these methods produce hydroprocessed biofuels as a primary product, they are also within the scope of the acetic acid production methods described herein, when recovery of acetic acid is also an objective of the overall method.
[0024] According to the exemplary embodiment depicted in the FIGURE, the acetic acid production method comprises separating pyrolysis reactor effluent 20 , or at least a portion thereof, in first separation stage 300 to provide first stage overhead product 22 and first stage bottoms product 24 . Acetic acid may then be recovered from either or both of the first stage products 22 , 24 . This recovery optionally follows various further processing steps, some or all of which may enrich a recovered intermediate or end product (e.g., a purified acetic acid product) in acetic acid and deplete the recovered product in other compounds produced from pyrolysis. A representative first separation stage 300 comprises a quenching tower and includes quench liquid recycle 26 , namely a portion of first stage bottoms product 24 that is recycled to the quenching tower. Heat exchanger 350 cools quench liquid recycle 26 to remove heat from first separation stage and thereby promote the net condensation of non-recycled part 28 of first stage bottoms product 24 from pyrolysis reactor effluent 20 . The quenching tower of first separation stage may include multiple stages of vapor-liquid equilibrium contacting to more completely separate compounds in pyrolysis reactor effluent 20 as desired in either first stage overhead or bottoms products 22 , 24 , depending on their relative volatility or boiling point. Contacting efficiency may be improved using packing or trays in first separation stage 300 .
[0025] Particular embodiments include recovering acetic acid from first stage overhead product 22 . An exemplary method according to such embodiments includes distilling at least a portion of first stage overhead product 22 to recover the acetic acid as a purified acetic acid product that is depleted, relative to first stage overhead product 22 in one or more higher boiling oxygenates (e.g., furfural and/or hydroxyacetone) and/or one or more lower boiling oxygenates (e.g., water). For example, according to the particular embodiment depicted in the FIGURE, the step of recovering acetic acid comprises distilling a portion of first stage overhead product 22 provided after separating light components in second separation stage 400 . In a specific embodiment, a flash separator may be used in second separation stage 400 to remove light components, and particularly non-condensible components and other light gases, in second stage overhead product 16 . Representative light components are selected from the group consisting of ammonia, methane, ethylene, propylene, CO, CO 2 , H 2 , N 2 , and mixtures thereof. As discussed above, some or all of these light components may be recycled to pyrolysis reactor 100 to provide at least some of the requirement for pyrolysis gas 12 , such as fluidizing gas.
[0026] As illustrated in the embodiment depicted in the FIGURE, acetic acid is recovered by distilling second stage bottoms product 30 , as a portion of first stage overhead product 22 that is depleted, relative to this product, in one or more lower boiling oxygenates (e.g., CO, CO 2 , and water), which are preferentially removed in second stage overhead product 16 . Recovery of acetic acid is therefore achieved, according to this embodiment, using acetic acid recovery column 500 , which may be operated to separate oxygenates having a higher boiling point than acetic acid, such as furfural and hydroxyacetone, into acetic acid recovery column bottoms product 32 and recover acetic acid primarily in acetic acid recovery column overhead product 34 together with water. This water may be separated from acetic acid recovery column overhead product 34 in one or more further, downstream purification steps (e.g., adsorption, distillation, or membrane separation, not shown in the FIGURE) to obtain a purified acetic acid product derived from pyrolysis and comprising at least about 95% by weight acetic acid. Alternatively, due to the relatively high concentration of water generally obtained in second stage bottoms product 30 , it may be advantageous to first remove water from this product, for example using membrane separation (not shown in the FIGURE), upstream of acetic acid recovery column 500 , thereby significantly reducing the energy otherwise required in this column to distill water overhead.
[0027] According to alternative embodiments, depending on the composition of second stage bottoms product 30 , acetic acid recovery column 500 may be operated to distill water substantially into acetic acid recovery column overhead product 34 and recover acetic acid primarily in acetic acid recovery column bottoms product 32 together with furfural, hydroxyacetone, and other oxygenates having a higher boiling point than acetic acid. Again, one or more further steps (e.g., adsorption, distillation, or membrane separation, not shown in the FIGURE) in the purification or separation of (i) acetic acid recovery column bottoms product 32 , downstream of acetic acid recovery column 500 and/or (ii) second stage bottoms product 30 , upstream of acetic acid recovery column 500 , may be used to obtain a purified acetic acid product derived from pyrolysis and comprising acetic acid in an amount as described above.
[0028] According to yet further embodiments of the invention, acetic acid may be recovered from first stage bottoms product 24 exiting first separation stage 300 . For example, with reference to the use of a first separation stage comprising a quenching tower that includes a quench liquid recycle, as discussed above, representative methods may comprise recovering the acetic acid from non-recycled part 28 of first stage bottoms product 24 . Specific embodiments directed to such methods comprise distilling at least a portion of non-recycled part 28 to recover the acetic acid as a purified acetic acid product.
[0029] Recovery of acetic acid may therefore be achieved using a distillation column downstream of first separation stage 300 , as discussed above, but according to these alternate embodiments acetic acid recovery column 500 ′ (shown in phantom in the FIGURE) is used to purify non-recycled part 28 of first stage bottoms product 24 , rather than second stage bottoms product 30 . More specifically, distilling at least a portion of non-recycled part 28 of first stage bottoms product 24 may be used to recover the acetic acid in either (i) an acetic acid recovery column overhead product 34 ′, as a purified acetic acid product that is depleted in one or more higher boiling oxygenates (e.g., sugars such as cellobiose) or (ii) an acetic acid recovery column bottoms product 32 ′, as a purified acetic acid product that is depleted in one or more lower boiling oxygenates (e.g., water).
[0030] As discussed above with respect to recovery of acetic acid from first stage overhead product 22 exiting first separation stage 300 , the use of acetic acid recovery column 500 ′ to purify non-recycled part 28 of first stage bottoms product 24 may be preceded or followed by one or more further steps (e.g., adsorption, distillation, or membrane separation, not shown in the FIGURE) in the purification or separation of (i) acetic acid recovery column bottoms product 32 ′ or acetic acid recovery column overhead product 34 ′, downstream of acetic acid recovery column 500 ′ and/or (ii) non-recycled part 28 of first stage bottoms product 24 , upstream of acetic acid recovery column 500 ′, in order to obtain a purified acetic acid product derived from pyrolysis and comprising acetic acid in an amount as described above.
[0031] Further aspects of the present invention relate to the operation of first separation stage 300 and/or second separation stage 400 , downstream of pyrolyis reactor 100 , in a manner that facilitates separation of acetic acid into, and consequently recovery of acetic acid from, either first stage overhead product 22 or first stage bottoms product 24 . For example, in embodiments comprising recovering the acetic acid from the first stage overhead product 22 , the step of separating at least a portion of pyrolysis reactor effluent 20 in first separation stage 300 may be carried out under first stage separation conditions (e.g., temperature, pressure, and/or recycle ratio) whereby first stage overhead product 22 comprises the majority (at least about 50%), and generally from about 50% to about 99%, of the acetic acid contained in pyrolysis reactor effluent 20 and separated in first separation stage 300 . According to more specific embodiments, first separation stage 300 may be operated under separation conditions whereby first stage overhead product 22 comprises typically from about 60% to about 98%, and often from about 70% to about 97%, of the acetic acid contained in pyrolysis reactor effluent. Separation conditions of first separation stage 300 may also, or alternatively, be such that first stage overhead product 22 comprises acetic acid in an amount of generally at least about 3% (e.g., from about 3% to about 20%) by weight, typically at least about 5% (e.g., from about 5% to about 15%) by weight, and often at least about 8% (e.g., from about 8% to about 12%) by weight.
[0032] In other embodiments comprising recovering acetic acid from the first stage bottoms product 24 (e.g., from the non-recycled part 28 of the first stage bottoms product 24 ), the step of separating at least a portion of pyrolysis reactor effluent 20 in first separation stage 300 may be carried out under first stage separation conditions (e.g., temperature, pressure, and/or recycle ratio) whereby first stage bottoms product 24 comprises the majority (at least about 50%), and generally from about 50% to about 99%, of the acetic acid contained in pyrolysis reactor effluent 20 and separated in first separation stage 300 . According to more specific embodiments, first separation stage 300 may be operated under separation conditions whereby first stage bottoms product 24 comprises typically from about 60% to about 98%, and often from about 70% to about 97%, of the acetic acid contained in pyrolysis reactor effluent. Separation conditions of first separation stage 300 may also, or alternatively, be such that first stage bottoms product 24 comprises acetic acid in an amount of generally at least about 6% (e.g., from about 6% to about 25%) by weight, typically at least about 10% (e.g., from about 10% to about 20%) by weight, and often at least about 12% (e.g., from about 12% to about 18%) by weight.
[0033] According to yet further embodiments, acetic acid may be recovered from both first stage overhead product 22 and first stage bottoms product 24 using acetic acid recovery columns 500 , 500 ′, optionally in conjunction with further steps (e.g., adsorption, distillation, or membrane separation, not shown in the FIGURE) in the purification of acetic acid from any of, any combination of, or all of, (i) acetic acid recovery column bottoms product 32 , (ii) acetic acid recovery column bottoms product 32 ′, (iii) acetic acid recovery column overhead product 34 , (iv) acetic acid recovery column overhead product 34 ′ (with steps involving products (i) through (iv) being downstream of acetic acid recovery columns 500 , 500 ′), (v) first stage overhead product 22 , and (vi) non-recycled part 28 of first stage bottoms product 24 (with steps involving products (v) and (vi) being upstream of acetic acid recovery columns 500 , 500 ′). With respect to any particular method for recovery and purification of acetic acid from pyrolysis reactor effluent 20 , according to preferred embodiments generally at least about 50% (e.g., from about 50% to about 99%), typically at least about 60% (e.g., from about 60% to about 97%), and often at least about 85% (e.g., from about 85% to about 95%) of acetic acid produced from the pyrolysis (e.g., present in pyrolysis reactor effluent 20 ) is recovered in one or more purified acetic acid products having a purity levels as described above (e.g., comprising at least about 95% by weight acetic acid).
[0034] Overall, aspects of the invention are directed to the recovery and purification of valuable compounds, and particularly oxygenates such as acetic acid, from pyrolysis of a renewable feedstock (e.g., biomass). The overall value of the pyrolysis product may be enhanced relative to the value obtained using conventional downstream processing techniques involving hydroprocessing of the raw pyrolysis oil, such that essentially all oxygenates are otherwise deoxygenated to hydrocarbons. Those having skill in the art, with the knowledge gained from the present disclosure, will recognize that various changes could be made in the methods described herein for producing acetic acid, without departing from the scope of the present invention. Mechanisms used to explain theoretical or observed phenomena or results, shall be interpreted as illustrative only and not limiting in any way the scope of the appended claims.
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Methods are disclosed for producing, from renewable carbon sources, acetic acid in an economical manner. In particular, these methods are directed to the separation and recovery of acetic acid as a substantial product (e.g., as much as 5% by weight or more) of biomass pyrolysis. For a given commercial biomass pyrolysis unit, the acetic acid yield can represent a significant quantity of that used in a major industrial applications such as purified terephthalic acid (PTA) production. According to some embodiments, pyrolysis conditions and/or flow schemes advantageously improve the recovery of acetic acid for a given purity level.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority to U.S. provisional patent application Ser. No. 60/578,793 filed Jun. 9, 2004 by the present inventor and entitled “Snovantage Snow Plowing System,” the contents which are incorporated herein by reference in entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This application pertains generally to the field of excavating, and more particularly to snow or ice removal using scraper blades with auxiliary wings or extensions. In one preferred embodiment, the invention is a snow plow blade having a central section, the central section leading and coupled to a skid-steer, and two pivotal wings extending beyond the skid-steer and central section, both wings which are each separately adjustable through a nearly one hundred and eighty degree arc.
2. Description of the Related Art
Most modern transportation is based upon wheels, which perform much better traveling over clear, dry roadways. In addition to facilitating vehicular travel, the clearing of snow will also facilitate melting and drying in the more temperate regions, which makes for much cleaner, less icy, and safer areas for persons to traverse. While snow is sometimes cleared manually, snow plow blades simplify and greatly accelerate the clearing of snow from a particular area. Plows also reduce the chance of physical over-exertion, which can lead to heart attacks, strokes and death in those with compromised cardiovascular systems. As a result, snow plows have become relatively indispensable in the “snow-belt” regions.
A large number of snow plow blades have been devised in the prior art, most which are supported upon and require movement of a separate machine. Common snow plows are coupled on the front of a vehicle such as an all-terrain vehicle (ATV) or automobile. In the case of the ATV, clearing a light snow in a relatively small space is quite feasible, but such plows are just not suitable for either larger areas or deeper snows. The ATV is not heavy enough nor powerful enough to move substantial snow. In the case of an automobile, a common sight in the “snow belt” is that of a pick-up truck, SUV or four-wheel drive with a large plow coupled to the front. These plows, which comprise the vast majority of smaller commercial snow-removal equipment, may be accompanied at a job site by skid-steers or the like that provide front-end loader capability. The front-end loader complements a plow truck by being able to lift the snow onto taller piles, and in some instances may be used to load snow into snow-hauling dump trucks or the like.
Municipalities frequently employ trucks that are much larger than pick-ups for snow plowing, generally with front-mounted plows in the form of a large and tall blade placed at an angle to the front of the truck. As the truck is driven forward, the snow is then pushed, or in some instances literally rolled and blown, off to the side. Once again, front-end or other types of loaders may be employed where there is not sufficient space to simply leave the snow pushed off to the side.
A common feature that each of the foregoing snow plows have in common is the width of the plow. In each case, the plow is designed to function essentially within the width of a single traffic lane. Said another way, the pickup truck with front-mounted blade must travel over the roadways, typically going from location to location to clear snow. During transit, the plow must fit within the allotted lane of the roadway. Consequently, the vast majority of plows are limited to clearing an approximately eight foot wide pathway. Furthermore, and as aforementioned, these plows are unable to pile the snow beyond a height limited by the height of the blade and weight and traction of the vehicle.
In some cases, road-grading equipment has been used to clear snow. Most road graders have the ability to pivot the blade about a vertical axis, and so the blade may be significantly longer than eight feet, since the blade may be oriented so that the longest dimension of the blade extends nearly parallel to the vehicle longitudinal axis during transit, and may later be pivoted to extend more perpendicular to the vehicle direction of travel for use at a site. However, road graders are very specialized and expensive machines, the price which is beyond most individuals and organizations that are involved in snow clearing and removal. Furthermore, most road graders are designed to carry the blade in the center of the vehicle, beneath the operator. Consequently, it is impossible to accumulate snow at any elevation much higher than the blade. In turn then, there are frequent times when snow must be hauled away which might otherwise simply be piled. If the snow must be hauled, then, in addition to the road grader, there must also be a suitably sized loader and hauler.
Some more recent equipment has included supplemental wings or extensions. In the case of road grading, an adjustable extension may enable the plow to not only grade a roadway, but through the wing extension a shoulder or even a ditch may be plowed. While such extensions are coming into more favor in the road grading industry and occasionally in the case of municipal plows, these extensions have heretofore been applied simply to permit the extension of reach from a traffic lane into a shoulder, ditch or the like. Furthermore, these extensions have offered no little further synergy, other than a larger or wider blade, or, in some cases, the ability to adjust angles to simultaneously address a roadway and a ditch or embankment. Exemplary of the technology, and the contents which are incorporated herein by reference, are the U.S. Pat. Nos. 3,430,706 by Marron, entitled “Slope cutting attachment for bulldozers,” which illustrates a wing blade that hydraulically adjusts from perpendicular behind the main blade to a significant angle forward of the main blade; 4,099,578 by Stevens, entitled “Hinged bulldozer blade,” which illustrates pivoting wingblades with hydraulic actuation cylinders from the main blade; 4,723,609 by Curtis, entitled “Double bladed combination scraper,” which illustrates hydraulic ram actuated side wings; 5,758,728 by Ragule, entitled “Plow with articulating blade,” which illustrates a segmented blade pivoted so two segments act together in configuring the wing section; 6,408,549 and 6,412,199 by Quenzi et al, which illustrate wings that pivot forward and have an extension that is hydraulically actuated; 5,285,588 by Niemela et al, entitled “Winged plow,” which discloses side gates for a plow blade that pivot from almost perpendicular to the main blade forward to just aft of parallel with the main blade; and 5,638,618 by Niemela et al, entitled “Adjustable wing plow,” which discloses wing blades that pivot from parallel to the main blade to forward of the main blade.
As this technology has been novelly adapted to the field of snow plowing, other artisans, as shown by the following patents, the teachings which are further incorporated herein by reference, have further adapted the wings. U.S. Pat. No. 5,819,444 by Desmarais, entitled “Snow blade with tilting lateral panels,” shows a pivot of side panels from fully to the rear to forward of parallel with the center blade by hydraulic ram. U.S. Pat. No. 5,829,174, U.S. Pat. No. 6,044,579 and U.S. Pat. No. 6,154,986 by Hadler et al, illustrate a small center blade and two wing blades adjustable forward and aft. U.S. Pat. No. 6,442,877 by Quenzi et al, entitled “Plow with rear mounted, adjustable wing,” discloses the general use of winged plow device for snow and other materials. The blade extends and retracts sideways, and pivots forward when extended. U.S. Pat. No. 4,479,312 by Targeon, entitled “Folding snow compactor with side wings pivotal behind central blade,” illustrates wings that pivot from stowed behind the main blade to fully extended sideways. U.S. Pat. No. 5,655,318 by Daniels, entitled “Snowplow with pivotal blade end extensions,” discloses wings that pivot between extended and stowed, and the blade is detachable from vehicle. U.S. Pat. No. 3,477,151 by Zanella, entitled “Snowplow,” illustrates wing blades that pivot from parallel to the main blade to forward positions through hydraulic actuation. Finally, U.S. Pat. No. 4,356,645 by Hine et al, entitled “Variable wing plow blade and mounting structure therefor,” illustrates wing blades that pivot forward and aft of parallel with center blade.
A number of other artisans have illustrated related subject matter, the teachings which are additionally incorporated herein by reference, including U.S. Pat. No. 3,206,879 by Grover; U.S. Pat. No. 4,077,139 by Fagervold et al; U.S. Pat. No. 5,018,284 by Mikami et al; U.S. Pat. No. 5,848,654 by Belcher; U.S. Pat. No. 5,860,230 by Daniels; U.S. Pat. No. 6,249,992 by Irving et al; and U.S. published application 2002/0194752 by Guinard.
SUMMARY OF THE INVENTION
In a first manifestation, the invention is a snow plow. The snow plow has a drive vehicle. A central plow section extends longitudinally from a first point to a second point and is coupled to and transported by the drive vehicle. The central plow section has a plow surface. At least one wing extends from the central plow section and pivotally couples thereto through a pivot. The at least one wing has a plow surface, and is pivotal about the central plow section substantially from perpendicular and leading the central plow section to perpendicular and trailing the central plow section. A powered extensible and retractable member is extensible and retractable along an axis of extension and retraction. A first pivotal coupling retains the powered extensible and retractable member to the central plow section adjacent a first end of the powered extensible and retractable member. The first pivotal coupling protrudes from the central plow section in a direction parallel to an axis between the first and second points but is not actually between the first and second points. The first pivotal coupling spaces the powered extensible and retractable member from the central plow section. A second pivotal coupling retains the powered extensible and retractable member to the at least one wing adjacent a second end of the powered extensible and retractable member distal to the first end and spacing the powered extensible and retractable member from the at least one wing plow surface. The second pivotal coupling protrudes from the central plow section and is located between framing members when the at least one wing is perpendicular to and trails the central plow section.
In a second manifestation, the invention is an excavating apparatus for scraping loose matter from a surface. A main blade has a pushing surface adapted to contact the loose matter. A vehicle coupler surface generally parallel to and spaced from the pushing surface terminates at two distally opposed ends at two pin hinges. Two distally opposed tapers have surfaces adjacent the pushing surface sloping from immediately adjacent the pushing surface away therefrom to ones of the pin hinges. A first wing is coupled to a first one of the two pin hinges and is pivotal thereabout. The first wing has a pushing surface, a back surface spaced from the first wing pushing surface, and a taper having a surface sloping from immediately adjacent the first wing pushing surface away therefrom to ones of the pin hinges. A power member is coupled between the main blade and first wing that is operative to pivot the wing and thereby move the first wing taper surface more nearly adjacent the main blade taper surface. The first wing taper surface is spaced less from the main blade taper surface more nearly adjacent a one of the pin hinges.
In a third manifestation, the invention is a snow plow. The snow plow has a main blade, with first and second wings flanking and pivotally coupled to the main blade at first and second main blade-to-wing pivots, respectively. A first power cylinder is coupled to the first wing at a first wing-to-cylinder pivot and coupled to the main blade at a first main blade-to-cylinder pivot. The first power cylinder is retractable to be shorter than a combined minimum distance between the first main blade-to-cylinder pivot and first wing-to-cylinder pivot and extendable to be longer than a maximum distance between first main blade-to-cylinder pivot and first wing-to-cylinder pivot summed with a maximum distance between the first main blade-to-cylinder pivot and the first main blade-to-wing pivot.
OBJECTS OF THE INVENTION
Exemplary embodiments of the present invention solve inadequacies of the prior art by providing a detachable snow plow blade which is useful in combination with a skid-steer or other suitable vehicle. The detachable plow blade has hydraulically adjustable wing blades adjusting separately from extending essentially perpendicular to and ahead of the main blade to essentially perpendicular to and behind the main blade. In a further alternative embodiment, the entire blade, including wing blades, may additionally be pivoted with respect to the vehicle, resulting in a very adjustable blade which is well adapted to a variety of uses and applications beyond those achievable heretofore in the prior art.
A first object of the invention is to only require nominal finished weight, while still being structurally engineered for strength and durability. A second object of the invention is to provide plows in different heights and widths, including widths which may be either substantially greater than the width of a traffic lane, such as, for exemplary purpose, 16, 18 and 20 foot widths, or narrower, as may be desired. Another object of the present invention is to enable the snow plowing system which achieves the foregoing objects to be easily loaded on a standard skid-steer trailer, without detachment from the skid steer and which may be transported through spaces of approximately the size of standard motive vehicles and within a single standard traffic lane. A further object of the invention is to provide snow plowing blades that are fully functional no matter what relative position they are in, thereby enabling the functions provided by a prior art box plow/pusher, conventional plow, pull back/drag, V-plow and a fold-out. Yet another object of the present invention is to enable plow wings, when in the most forward position, to glide effortlessly over sidewalks and curbs, minimizing both surface damage and the possibility of damage to the motive machine or the present inventive snow plowing system.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other objects, advantages, and novel features of the present invention can be understood and appreciated by reference to the following detailed description of the invention, taken in conjunction with the accompanying drawings, in which:
FIG. 1 illustrates a preferred embodiment snow plowing system designed in accord with the teachings of the invention from a projected plan view, with the left and right wings extending generally perpendicularly from and leading the center section.
FIG. 2 illustrates the preferred embodiment snow plowing system of FIG. 1 from a top plan view.
FIG. 3 illustrates the preferred embodiment snow plowing system of FIG. 1 from a side plan view.
FIG. 4 illustrates the preferred embodiment snow plowing system of FIG. 1 from a top plan view, with the left and right wings extending generally parallel to the center section.
FIG. 5 illustrates the preferred embodiment snow plowing system of FIG. 4 from a rear and slightly projected view.
FIG. 6 illustrates the preferred embodiment snow plowing system of FIG. 1 from a projected plan view, with the left and right wings extending generally perpendicularly from and trailing the center section.
FIG. 7 illustrates the preferred embodiment snow plowing system of FIG. 6 from a side and slightly projected view.
FIG. 8 illustrates a first alternative embodiment snow plowing system designed in accord with the teachings of the invention from a top plan view, and with the right wing removed therefrom for illustrative purposes.
FIG. 9 illustrates a connecting linkage utilized in the first alternative embodiment snow plowing system of FIG. 8 from a projected rear plan view, with the balance of the snow plowing system removed for illustrative purposes.
FIG. 10 illustrates the first alternative embodiment snow plowing system of FIG. 8 from a top plan view, in combination with an exemplary land vehicle and in further combination with a cylinder for pivoting the main blade relative to the motive vehicle, with the left wing forward of the main blade, the right wing trailing the main blade, and the main blade offset from perpendicular to the direction of travel of the land vehicle.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Manifested in the preferred embodiment, the present invention provides a snow plowing system 100 which comprises three main sections. A main blade 110 is flanked on opposite ends by right wing 130 and left wing 150 . FIGS. 1-3 illustrate preferred embodiment snow plowing system 100 having right and left wings 130 , 150 extending generally perpendicularly from and leading centrally located main blade 110 . For the purposes of the present disclosure, the words leading and trailing will be understood to be assumed for a direction of typical forward travel by a vehicle coupled as shown for exemplary purposes in FIG. 10 , wherein such a vehicle would normally travel in a forward direction from the back side of main blade 110 , adjacent coupling 116 , and will be urging against coupling 116 towards surface 115 . Nevertheless, one of the features and benefits of the preferred embodiment is the ability to push or pull. Consequently, the words leading and trailing are simply for the purposes of illustration, and are not limiting to the operational capabilities of the invention.
Main blade 110 has a plowing face 115 which will serve to move snow forward when snow plowing system 100 is being driven forward. In this forward direction of travel, snow will be trapped between plowing faces 135 and 155 as well, and in fact may even be compacted therebetween if right and left wings 130 , 150 are urged towards each other. This is accomplished by extending one or both of power cylinders 140 , 160 , the operation which will be described further herein below. As the power cylinders are extending, they will in turn urge the associated wing to pivot about hinge pins 136 , 156 , which in turn reduces the distances between wing tip 131 and wing tip 151 . As this distance between wing tips 131 , 151 decreases, any snow held therein will either be displaced or compacted, depending upon how much snow is therebetween, the characteristics of the snow, and other similar factors.
With wings 130 , 150 leading main blade 110 , as illustrated in FIGS. 1-3 , wing tips 131 , 151 will be the first points of contact with any obstacles that might commonly be encountered, such as curbs, parking curbs, sidewalk, and other such obstacles. Wing tips 131 , 151 have been rounded on the lower side thereof into curved surfaces 132 , 152 , which are preferably designed to much more readily raise up over any obstacles that might be encountered. By raising, rather than binding, curbs and other obstacles are protected from damaging contact during typical plowing operations. Furthermore, when an obstacle is unexpectedly encountered while traveling forward at greater speeds, this gentle rounding of curved surfaces 132 , 152 will also help to protect both snow plowing system 100 and a driving vehicle from potentially damaging impacts.
In preferred embodiment snow plowing system 100 , wings 130 and 150 are able to pivot about hinge pins 136 , 156 , respectively, each approximating a full one-hundred and eighty degrees of rotation. This unusually large range of motion is provided by the novel arrangements illustrated herein. More particularly, cylinder 140 is coupled at a first end to pin 122 , and is free to pivot thereabout. However, cylinder 140 is otherwise restrained between top bracket 120 and bottom bracket 121 . Likewise, distal to pin 122 is pin 141 , which serves a like function to pin 122 . Cylinder 140 is similarly coupled thereto and free to rotate there about. Restraining cylinder 140 vertically adjacent pin 141 are top bracket 139 and bottom bracket 138 . As cylinder 140 is extended, tip 131 will be pivoted closer to tip 151 . Limiting the extent of forward rotation is the potential interference between cylinder 140 and hinge 134 . To allow greater movement before such interference occurs, hinge 134 is absent in a small void 137 adjacent cylinder 140 . Consequently, the first interference with cylinder 140 , as cylinder 140 is extended, will in the preferred embodiment occur between cylinder 140 and hinge pin 136 . Rather than allow such interference, cylinder 140 will most preferably stop at a point of maximum travel just prior to interfering with hinge pin 136 . Like construction and operation, only in mirror image, exists with cylinder 160 , pins 125 , 161 , upper bracket 123 , lower bracket, pin 125 , hinge body 154 , small void 157 , upper bracket 159 , lower bracket 158 , and pin 161 .
If wings 130 , 150 terminated in a rectangular end adjacent main blade 110 , when viewed from a top view as in FIG. 2 , there would also be interference to rotation between these rectangular ends. Such interference is known in the prior art. However, in the present invention, plowing faces 135 , 155 end with angled tapers 133 , 153 adjacent hinges 134 , 154 , respectively. These angled tapers cooperate with similar tapers 112 , 113 on main blade 110 , adjacent plowing face 115 . Consequently, when in the forward position illustrated in FIG. 1 , there is no pinching occurring between wings 130 , 150 and main blade 110 . Instead, there are preferably small gaps between angled tapers 113 and 153 , and also between angled tapers 112 and 133 . These gaps allow ice and snow to be expelled, rather than trapped, when wings 130 , 150 are pivoted. Further, there is no chance for ice to be formed between wings 130 , 150 and main blade 110 which would prevent relative motion therebetween.
As best viewed in FIG. 3 , upper bracket 120 is slightly below wing upper brace 142 . Lower bracket 121 is just slightly higher than wing lower brace 143 . This relative placement is critical to the proper performance of this hinge, as will be further explained with regard to FIGS. 6 and 7 .
FIGS. 4 and 5 illustrate the preferred embodiment snow plowing system 100 of FIG. 1 from a top plan view, with the left and right wings extending generally parallel to the center section. This placement of wings 130 , 150 relative to main blade 110 is intermediate in rotation. Since in this position wings 130 , 150 extend longitudinally with main blade 110 , this will also present the greatest plowing width. Single plow blades of the prior art are limited in width to the width of main blade 110 , which is in turn limited to the width of a roadway traffic lane. As is apparent, the present invention effectively plows a width far greater, limited only by the motive strength of the vehicle, the strength of each hydraulic cylinder 140 , 160 , and the materials used in the fabrication of wings 130 , 150 and wing upper and lower braces 142 , 143 , 162 , 163 .
FIGS. 6 and 7 illustrate the preferred embodiment snow plowing system 100 of FIG. 1 , with the left and right wings extending generally perpendicularly from and trailing the center section. Most visible in FIG. 6 is the placement of top bracket 159 , bottom bracket 158 , and pin 161 . As may be seen, brackets 158 , 159 and pin 161 all fit within a space between upper brace 162 and lower brace 163 . Furthermore, as can be seen comparing FIGS. 2 and 6 , cylinder 160 is significantly shorter as shown in FIG. 6 than in FIG. 2 . In fact, viewing FIG. 2 , cylinder 160 is an amount shorter which is approximately equal to twice the distance between pin 125 and hinge pin 156 . This is because the distance between hinge pin 156 and pin 161 is essential constant, irrespective of the position of wing 150 . However, in the position of FIG. 2 , cylinder 160 has to traverse not only the distance between hinge pin 156 and pin 161 , it must also traverse approximately the distance between hinge pin 156 and pin 125 . When in the position illustrated in FIG. 6 , cylinder 160 is traversing the distance from pin 161 to hinge pin 156 , less the distance from hinge pin 125 to hinge pin 156 . Consequently, assuming that cylinder 160 is a double acting cylinder which can be driven to both extend and retract, driving cylinder 160 to extend will cause wing 150 to rotate towards the forward-most position illustrated in FIG. 2 . Retracting cylinder 160 will cause wing 150 to rotate towards the rearward position illustrated in FIG. 6 . Consequently, cylinder 160 can be used to drive wing 150 through an approximately one-hundred and eighty degrees of rotation. In practice, a slightly smaller amount of rotation is desired to ensure that with plow loads, manufacturing tolerances, and other similar factors there is no chance of either wing 130 or wing 150 from ever passing beyond the one-hundred and eighty degree point. Consequently, an approximately one-hundred and sixty-five degrees of rotation is most preferred.
FIG. 7 shows very clearly the small void 137 in hinge 134 , which presents a space within which cylinder 140 may safely pass without interference. In addition, from this figure the preferred curvature of plow face 115 is illustrated. Similar curvatures are most preferably used for plow faces 135 , 155 , though each of these plow faces will have curvatures or shapes that are most suited for their function and application. In other words, these plow faces 115 , 135 , 155 may be provided with compound surfaces or compound curvatures as desired at the time of design by an artisan.
While very little discussion has been provided herein above with regard to vehicle coupling 116 , it will be understood that a relatively universal coupling may be provided which will couple directly to a large number of prior art vehicles. In the preferred embodiment, coupling 116 is in fact such a coupling, designed for coupling to a large number of skid-steers and like vehicles. Nevertheless, any suitable type of coupling may be used, and the type selected will be dependent upon the vehicle to which the invention is coupled as well as the ultimate dimensions ofboth vehicle and embodiment of the invention. Similarly, readily replaceable wear strips such as wear strip 145 may be provided, which will extend the useful life of snow plowing system 100 .
FIG. 8 illustrates a first alternative embodiment snow plowing system 200 designed in accord with the teachings of the invention from a top plan view, and with the right wing removed therefrom for illustrative purposes. Where functionally identical or similar components are illustrated, numbering has been preserved to so designate, by using like ones and tens digits. So, for example, power cylinder 260 of snow plowing system 200 is functionally equivalent to power cylinder 160 of snow plowing system 100 . Where such similarity exists, a minimal amount, if any, further description will be provided with regard to this first alternative embodiment.
Snow plowing system 200 is provided with a special vehicle coupling 270 which is designed to enable an operator to change the orientation of main blade 210 relative to the direction of travel. While support 271 will normally be rigidly coupled to the vehicle, power cylinder 280 may be extended to cause main blade 210 to be at angle relative to support 271 , and consequently at some angle other than perpendicular with respect to the direction of forward travel.
The specific components of special vehicle coupling 270 include supports 271 , 281 , coupling pins 272 , 273 for coupling power cylinder 280 at distal ends, three flexible or universal-style joints 274 , 276 , and 277 , and a short linkage 275 . Linkage 275 is most preferably included, since this allows main blade 210 to swivel forward and backward to limited degree, in the event troublesome obstacles are encountered during plowing.
FIG. 10 illustrates the first alternative embodiment snow plowing system 200 in combination with an exemplary land vehicle 300 having drive tracks 310 , 320 . As illustrated, power cylinder 280 for pivoting the main blade relative to the motive vehicle is slightly extended, the left wing is forward of the main blade, the right wing is trailing the main blade, and the main blade is offset from perpendicular to the direction of travel of the land vehicle. This arrangement is but one of a myriad of possible configurations. For exemplary purposes only, and not limited thereto, an operator might extend power cylinder 280 sufficiently far that hinge pin 256 is more nearly in front of vehicle 300 . If wing 250 is then dropped back to trail hinge 254 , and wing 230 is extended parallel to main blade 210 , the resulting configuration is that of a “V” plow, with tapered edges 213 , 253 and hinge 254 leading during plowing.
As may be apparent from the illustrations, the particular motive vehicle used is not critical to the invention. Nor is the type of drive. Consequently, tracked or wheeled vehicles may be used. The most preferred embodiment is fully welded, finished with a multi-color powder coating and is provided with replaceable cutting edges such as edge 145 illustrated in FIG. 3 . While dimensions are not critical to the performance of the present invention, and instead are provided solely as a point of reference, the preferred embodiment moldboard is 32″ high and may, for example, be provided in different heights or widths, such as 16, 18 and 20 foot widths. A standard width vehicle for operation within a traffic lane is limited to approximately 8 feet.
Most preferably, a preferred snow plow system designed in accord with the present invention may be set with the wings either leading or trailing, permitting the preferred snow plowing system to be easily loaded on a standard skid-steer trailer without detachment from the skid steer. The wings may be positioned as shown in either FIG. 3 or FIG. 7 to permit passage through spaces only a few inches wider than motive vehicle 300 .
As should also be apparent, the snow plowing system blades are fully functional no matter what position they are in. In other words, each of the figures represent operable positions. In the preferred embodiment, wing blades 130 , 150 are pivotally attached to main blade 110 . Power cylinders, such as but not limited to hydraulic cylinders, are mounted and attached to create motion between the wings and center section through a wide range, preferably meeting or exceeding a 165 degree operating range. This range is illustrated in the contrast between FIGS. 3 and 7 .
Snow plowing system blades designed in accord with the preferred embodiments of the invention are fully functional no matter what position they are in. As a result of the range of motion of the wings provided by the disclosed mechanical coupling, the preferred snow plowing system has the features of a box plow/pusher, conventional plow, pull back/drag, V-plow and a fold-out. The unique box plow/pusher and conventional plow position permits an operator to clear parking lots many times faster than a conventional plow. Bringing the side blades forward permits the operator to capture and compact large amounts of snow. Consequently, the operator may then push snow for long distances and place the snow as high as the motive machine can reach. Back-dragging of loading docks, parking lots and driveways are very much simplified over the prior art. Maneuverability of the blades gives the operator greater visibility, permitting the present snow plowing system to be used to clear snow and debris within inches of curbs, building fronts, sidewalks, vehicles, aircraft, utility poles and other obstacles. An operator may navigate around the obstacle in a single continuous motion, simply by moving the adjacent wing to a more forward position while proceeding forward, passing the obstacle, extending the wing back to parallel, and continuing. When the wings are folded back, the operator may, for exemplary purposes, plow a driveway in one pass. Most preferably for this example, the total plow width is sized to exceed the width of the driveway. In this case, the trailing wings ensure that the present snow plowing system moves snow deeper into ditches and off the roadway. Finally, the present snow plowing blades maximize visibility available to an operator.
The preferred wear edge 145 visible in FIG. 3 is uniquely positioned and has more wear surface on the ground, thereby creating less pressure on the wear edge, in turn reducing wear and friction and thereby enabling the snow plowing system to be larger for a given skid-steer. With proper design, preferred wear edge 145 and geometries illustrated herein will slide smoothly across pavement and grass, and eliminate need for plow shoes.
As discussed herein above, the motive vehicle is not limited to one or another type of vehicle, and the preferred embodiment will perform well with both rubber tire and track vehicles. Additionally, while the preferred embodiment uses hydraulic cylinders, it will be recognized by those reasonably familiar with the art that other devices may be used to position the wings and center section, and may include various apparatus and power sources.
From these figure, several additional features and options become more apparent. First of all, the snow plowing system may be manufactured from a variety of materials, including metals, resins and plastics, ceramics or cementitious materials, or even combinations of the above. The specific material used may vary, though special benefits are attainable if several important factors are taken into consideration. Firstly, the snow plowing system will preferably be simply attached to a variety of suitable machines or equipment capable of providing motive power. Most preferably, the preferred snow plowing system will also be weather resistant and sufficiently durable to withstand the vagaries of extreme temperatures, preferably to include both hot and cold, while enduring any forces that may be applied that could tend to fracture or shear the various components. Additionally, resistance to abrasion or seizing from aggregate, ice, sticks and posts, and other various objects that may be encountered will generally be preferable. The actual engagement between the snow plowing system and motive vehicle is, as already noted, dependent upon the motive vehicle and application but will preferably accommodate as many different vehicle couplings as may be possible.
The most preferred material for the structural components of the snow plowing system is powder coated steel. Other materials or ingredients may be provided to enhance the abrasion resistance, weather resistance, and other properties of the coating and resulting product. A variety of designs have been contemplated for the snow plowing system. The tapers illustrated herein are most preferred, but those skilled in the art will recognize upon suggestion that other geometries may be designed or incorporated. Furthermore, where desired, ornamentation may additionally be provided. The materials used for a particular design may be chosen not only based upon the aforementioned factors such as weather resistance and weight, but may also factor in the particular design. Other variations are also contemplated herein with regard to alternative embodiments, such as the use of a single wing, or any of a myriad of other possible alternatives. Furthermore, while the present invention is most suited for the plowing of snow, the moving or handling of other materials is contemplated herein.
Therefore, while the foregoing details what is felt to be the preferred embodiment of the invention, no material limitations to the scope of the claimed invention are intended. The variants that would be possible from a reading of the present disclosure are too many in number for individual listings herein, though they are understood to be included in the present invention. Further, features and design alternatives that would be obvious to one of ordinary skill in the art are considered to be incorporated herein. The scope of the invention is set forth and particularly described in the claims herein below.
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A detachable snow plow blade is driven by a skid-steer or other suitable vehicle. The detachable plow blade has hydraulically adjustable wing blades that each pivot under separate control about a main blade. Pins that support power cylinders between braces are arranged to enable each wing to extend through a range of motion from essentially perpendicular to and ahead of the main blade to essentially perpendicular to and behind the main blade. In a further alternative embodiment, the entire blade, including wing blades, may additionally be pivoted with respect to the vehicle, resulting in a very adjustable blade which is well adapted to emulate prior art box plow/pushers, conventional plows, pull back/drag plows, V-plows and fold-out plows.
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BACKGROUND OF THE INVENTION
[0001] The present invention relates to the assembly of precast construction elements for building prestressed structures.
[0002] It applies in particular, but not exclusively, to the decks of cantilevered bridges built using precast concrete elements (segments). These structures are frequently subjected to longitudinal prestressing using prestressing tendons threaded inside sheaths embedded in the concrete of several successive elements.
[0003] Carrying out such prestressing is a difficult operation. The positioning of the sheath sections in the elements must be very accurate so that the prestressing tendons can be threaded without difficulty.
[0004] Moreover, the sealing of the sheath at the interfaces between the elements must be ensured. This sealing is necessary to ensure the durability of the prestressing, which is subject to the risk of infiltrations at the joint between the elements.
[0005] When the joint is made using the so-called “wet joint” method, an interface product such as concrete or mortar fills the gap between two adjacent elements. In this case, the seal also meets the need to prevent the interface product, or certain components of it, from entering the sheaths when it is placed between the elements, and then hindering the insertion of the tendons.
[0006] Furthermore, the sheaths are often injected with a filler (cement grout, grease, wax, resin, etc.) serving in particular to protect the tendons against corrosion. This product must not escape from the sheath during injection. Some areas of the structure can have a relatively high density of sheaths, and there is no guarantee that the interface product will produce a seal between these sheaths. As a result, there is a serious risk that grout injected under pressure into a sheath will infiltrate into one or more neighbouring sheaths, in which injection then becomes very difficult or even impossible.
[0007] FR-A-2 596 439 describes a linking device between sections of prestressing sheath, comprising a cylindrical sleeve engaged between the openings of two adjacent sections to ensure the continuity of the sheath, and an elastic seal surrounding the cylindrical sleeve to ensure sealing and compensate for the positioning variations and dimensional deviations of the blocks, which are assembled against each other.
[0008] WO 99/043910 describes an improvement of the construction methods in which the elements are matched and then assembled in contact with each other. The matched elements are cast using the so-called “match cast” technique in which the front surface of an n th element defines the rear side of the mould used to shape the (n+1) th element of the series. When each element is cast, sleeves are arranged at the ends of the sheath sections that they contain. The complementary surfaces of the matched elements are then pressed against each other so that the sheath sections are arranged running on from each other to form complete sheaths. Positioning connectors are engaged in the sleeves to connect the adjacent sheath sections in a sealed manner.
[0009] This last technique is well-suited to elements cast using the “match cast” technique, which ensures accurate mutual positioning of the adjacent sections of a prestressing sheath. However, its implementation can be difficult if a “wet joint” method is used. In this case, the elements are often factory cast with significant dimensional tolerances, and the gap between the adjacent surfaces of two successive elements can be several centimetres.
SUMMARY OF THE INVENTION
[0010] The present document relates to an assembly technique for precast elements that provides an answer to the issue of sealing the sheaths when a “wet joint” method is used.
[0011] It sets out a construction method for a prestressed structure having a series of precast elements. This method comprises the steps of: obtaining two successive elements in the series, each of the two elements incorporating at least one prestressing sheath section and an end piece linked to said sheath section and opening out on a surface of said element, the end piece incorporated into one of the two elements having a flared opening; connecting in a sealed manner an elastic connecting sleeve to the end piece incorporated into the other element; arranging the two successive elements relative to each other, maintaining a gap between two adjacent surfaces of the elements, the connecting sleeve being engaged in said flared opening and compressed longitudinally by the bringing together of the elements, the compression of the connecting sleeve ensuring a seal between the inside of the sheath sections and the gap between the adjacent surfaces of the elements; and placing an interface product in the gap between the adjacent surfaces of the elements.
[0012] The elastic connecting sleeve separates in a sealed manner the inside of the prestressing sheath from the gap between the two elements, which must be filled with concrete or another interface product. The arrangement allows for a seal to be produced without accessing the connecting area, which is prevented by the narrowness of the gap between the elements. However, this gap has a significant thickness and its dimensions are not accurately guaranteed given the manufacturing tolerances of the elements and possible inaccuracies on assembly. There can also be misalignments between the sheath sections and end pieces relative to their theoretical positioning in the elements. The gradual flaring of at least one of the end pieces and the elasticity of the connecting sleeves that extend between the two end pieces allows for them to be deformed in such a way as to compensate for the various deviations and inaccuracies linked to the manufacturing and assembly of the elements.
[0013] The gap between the adjacent surfaces of the elements can for example have a thickness of between 3 and 6 centimetres. A typical order of magnitude for the longitudinal compression capacity of the connecting sleeve is a capacity greater than one centimetre. Moreover, a typical order of magnitude for the misalignment between the two end pieces permitted by the connecting sleeve is in an angular range greater than one degree.
[0014] Another aspect of the invention relates to a building structure comprising: an assembly of at least two precast elements having two respective facing surfaces separated by a gap occupied by an interface product; at least one prestressing sheath having two sections respectively incorporated into the precast elements; and a prestressing tendon tensioned inside the sheath. The sheath sections are respectively fitted with first and second end pieces opening out on the facing surfaces of the two precast elements, the first end piece having a flared opening. An elastic connecting sleeve connected in a sealed manner to the second end piece is pressed against the first end piece, which compresses it longitudinally to provide a seal between the inside of the sheath sections and the gap separating said surfaces.
[0015] A further aspect of the invention relates to a connection system for prestressing sheath sections, comprising: first and second end pieces, each having a rear side capable of being connected to a sheath section incorporated into a respective precast construction element and a front side to open out on a surface of said element, the front side of the first end piece having a flared opening; and an elastic connecting sleeve having one side capable of being connected in a sealed manner to the second end piece and an opposite side capable of cooperating with the first end piece, the connecting sleeve having a longitudinal compression capacity and a transverse deformation capacity in order to be compressed when said surfaces of the elements are brought together, whilst permitting an offset and misalignment between the two end pieces, the compression being capable of providing a seal between the inside of the sheath sections and a gap separating said surfaces.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Further features and advantages of the present invention will become apparent from the following description of non-limitative embodiment examples, with reference to the attached drawings.
[0017] FIG. 1 is a perspective view of a precast segment to which the method according to the invention can be applied.
[0018] FIG. 2 is a diagram showing the juxtaposition of two adjacent segments equipped with prestressing sheath sections and forming part of a series of precast elements.
[0019] FIG. 3 is a block diagram of a connection system according to one embodiment of the invention.
[0020] FIG. 4 is a diagram of a female end piece of the system in this embodiment.
[0021] FIG. 5 is a diagram showing a possible arrangement of a prestressing sheath section near the end surface of an element.
[0022] FIGS. 6 and 7 are respectively profile and front diagrammatic views of a variant embodiment of a female end piece of the connection system.
[0023] FIG. 8 is a longitudinal cross-sectional view of another embodiment of the connection system according to the invention.
DESCRIPTION OF EMBODIMENTS
[0024] The invention is described below in its non-limitative application to the cantilever construction of a precast segment bridge.
[0025] Such a segment 1 is shown in FIG. 1 . The element 1 has the general form of a caisson delimited at the bottom by a base 2 , laterally by two symmetrically sloping walls 3 , and at the top by a deck 4 extended laterally beyond the walls 3 to define the width of the bridge.
[0026] In the longitudinal direction, the element 1 is delimited by substantially parallel rear 7 and front 6 surfaces. The rear surface 7 is intended to face the front surface, of complementary shape, of the previous element installed on the structure under construction (for the first element installed on a pier of the bridge, the complementary surface belongs to the pier). Similarly, the front surface 6 of the element 1 is intended to face the rear surface of the next element to be installed. The complementary shaped surfaces of the adjacent elements can possibly be provided with bosses 8 facilitating the relative positioning of the elements when they are brought together.
[0027] The element 1 (or 1 A, 1 B in FIG. 2 ) comprises a number of longitudinal sheath sections 10 ( 10 A, 10 B in FIG. 2 ) intended to receive prestressing tendons 15 . The prestressing tendons 15 are anchored onto the structure at their ends by means of appropriate anchors. Some of these anchors 11 can possibly be arranged on sheaves 12 provided inside the caisson shape of the element. The sheath sections 10 open out on the rear surface 7 and/or the front surface 6 of the element. The continuity and sealing of each prestressing sheath 10 must be ensured at the interfaces between the elements. To this end, a connection system is used, embodiments of which are described below with reference to FIGS. 3 to 8 .
[0028] After the positioning of an element 1 B with a connection system installed at the joints of the sheath sections 10 A, 10 B, an interface product 16 , which will generally be concrete, is injected into the gap between the element 1 B and the previous element 1 A in the series. This gap typically has a thickness of between 3 and 6 centimetres. The sealing of the sheath is important to prevent components of the interface concrete 16 entering the sheath 10 , which would hinder the subsequent threading of the tendons 15 .
[0029] Once the interface concrete has set, the next element is assembled. If one (or several) prestressing sheaths 10 has its (their) last section in the element that has just been installed, the threading, anchoring and tensioning of a prestressing tendon 15 in this sheath can take place, possibly after having checked the seal using a pneumatic device. Threading can be carried out using conventional techniques. After tensioning, filler, generally cement grout, is injected into the sheath 10 to protect the metal of the tendon 15 against corrosion. The sealing of the sheath is important to prevent grout injected in a fluid state from escaping at the interfaces between the elements.
[0030] The successive elements 1 , 1 A, 1 B of the series are prefabricated from cast concrete. In the embodiment shown in FIG. 3 , the rear surface 7 of element 1 B is facing the front surface 6 of the previous element 1 A in the series. At the interface, the sheath sections 10 A, 10 B embedded in the concrete of elements 1 A, 1 B are respectively provided with two end pieces 20 A, 20 B also incorporated into the concrete of the element and made for example from a rigid plastic material. In the example shown, a male end piece 20 A has its rear side connected to the sheath section 10 A incorporated into the element 1 A already in place on the structure, whilst a female end piece 20 B has its rear side connected to the sheath section 10 B of the new element 1 B on its rear surface 7 . The end pieces 20 A, 20 B are connected to the sheath sections 10 A, 10 B in a sealed manner, and are placed in the mould used to produce the elements 1 A, 1 B. In general, the end pieces 20 A, 20 B do not extend beyond the end surface 6 , 7 of the element, for reasons of ease of casting. They can be positioned in the mould using studs positioned at the appropriate places on the inside surfaces of the walls of the moulds. After form removal, the front sides of the end pieces 20 A, 20 B open out on the surfaces of the elements, which will be placed facing each other when the bridge deck is assembled.
[0031] In addition to the end pieces 20 A, 20 B, the connection system shown in FIG. 3 comprises an elastic connecting sheath 21 made from an elastomer material. To enhance the elasticity of the sleeve 21 and its deformability in both an axial direction and transverse to the direction X of the sheath at the interface between the elements, the sleeve can be shaped like a bellows, as shown in FIG. 3 .
[0032] The sleeve 21 is connected in a sealed manner to the male end piece 20 A of the connection system. This connection is for example achieved by clipping or by screwing the rear side of the sleeve 21 in the male end piece 20 A. It takes place after the forms have been removed from the element 1 A. The front side of the connecting sleeve 21 cooperates with the female end piece 20 B of the facing element. The sleeve 21 and the end pieces 20 A, 20 B are sized so that the sleeve 21 is compressed axially when the two elements 1 A, 1 B are brought together on assembly.
[0033] The female end piece 20 B has an opening 22 that flares gradually as shown in FIGS. 3 and 4 . This flare 22 facilitates the insertion of the connection sleeve 21 without it being necessary to manipulate it when the elements 1 A, 1 B are brought together.
[0034] The elasticity of the sleeve 21 allows for tolerances to be permitted in the accuracy of the production of the concrete elements 1 A, 1 B, which tolerances are usually several centimetres. The sleeve 21 should therefore have a longitudinal compression capacity greater than 1 cm.
[0035] Furthermore, it is very difficult to accurately guarantee the positioning of the sheath sections 10 A, 10 B parallel to the surfaces 6 , 7 of the elements, as well as their orientation relative to these surfaces. The capacity of the sleeve 21 to deform transversely at the joint plane between the elements 1 A, 1 B also allows for these inaccuracies to be absorbed. The misalignment between the end pieces 20 A, 20 B of the sheath sections that the sleeve 21 can compensate for is greater than 1 degree and can even be around 10 degrees or more.
[0036] The gradual flaring of the opening of the female end piece 20 B can be of frusto-conical shape, as shown in FIG. 4 , with a half-cone angle α sufficient to facilitate the approach of the elastic connecting sleeve 21 . The flare 22 allows for the end of the connecting sleeve 21 to be conveyed to a recess 23 provided at the bottom of the female end piece when the two elements are brought together. The front end of the sleeve 21 can be shaped so that it nests firmly in the recess 23 in order to ensure, by clipping, a sealed connection under the action of the return force exerted due to the elasticity of the compressed sleeve. The flare 22 can also contribute to deforming the sleeve 21 if the two sheath sections are not exactly aligned. For a frusto-conical flare 22 of length L, the cone must have a sufficient opening at its base for the sleeve 21 to enter fully into the cone during the bringing together of the two elements 1 A, 1 B. The flare 22 must then compensate for: the effect of any local gradient β of the sheath relative to the joint plane between the elements 1 A, 1 B (see FIG. 5 ); the effect of the positioning inaccuracy of the two end pieces 10 A, 10 B in relation to each other (offset Δ parallel to the joint plane); the fact that the sleeve 21 is unfolded, i.e. not compressed, by a length D on bringing together.
[0037] Under these conditions, the minimum opening angle α of the cone verifies:
[0000]
tan
α
≥
tan
β
+
Δ
L
×
cos
β
+
D
×
tan
β
L
(
1
)
[0038] Moreover, the opening of the cone can facilitate the sliding of the sleeve 21 towards the recess 23 despite the friction of the sleeve on the female end piece 20 B, whatever the mutual positioning defect of the end pieces. If the friction is defined by a cone with a half cone angle φ, another condition on the maximum opening of the frusto-conical flare 22 is:
[0000] α<90°−β−φ
[0039] The frusto-conical shape with a circular cone for the flare 22 has the advantage of being simple to produce. It also allows for the avoidance of any ambiguity in the direction of placing the female end piece 20 B in the formwork, and therefore of any risk of error.
[0040] In certain cases however, the opening of the cone at the end surface 6 , 7 of the element can have relatively large dimensions, which can be problematic, particularly when several neighbouring prestressing sheaths have to cross the gap between the two elements. Moreover, if the sheaths are embedded in a relatively narrow concrete part, such as a segment web, the width of the cone can become significant relative to the total width of the part and lead to a weakening of the structure.
[0041] In the minimum angle condition (1), it can be observed that only the term
[0000]
Δ
L
×
cos
β
[0000] relating to the positioning tolerance of the end pieces relative to each other is omnidirectional. The other two terms relating to the gradient of the sheath and the extension of the sleeve only operate in an a priori known direction, namely the direction of minimum angle between the sheath section 10 B and the joint plane. This direction of minimum angle is the direction in which the angle β is shown in FIG. 5 .
[0042] Under these conditions, it can be prudent to provide an anisotropic flare of the female end piece, as shown in FIGS. 6 and 7 . In this embodiment, the front side of the female end piece 30 B has one half provided with a frusto-conical circular flare (lower part of FIGS. 6 and 7 ), with a half-cone angle α′ of the order of
[0000]
Arc
tan
(
Δ
L
×
cos
β
max
)
[0000] where β max is the maximum gradient of the sheath relative to the joint plane. The other half of the front side of the female end piece 30 B (upper part of FIGS. 6 and 7 ) has a flare in the shape of a cone with an elliptical base, the half cone angle α of the cone on the major axis of the ellipse verifying condition (1), α then being of the order of
[0000]
Arc
tan
(
tan
β
max
+
Δ
L
×
cos
β
max
+
D
×
tan
β
max
L
)
.
[0043] For the assembly of such a female end piece 30 B on its sheath section 10 B in the mould for the concrete element, the end piece is oriented so that it presents its maximum flare, that is, the major axis of the elliptical shape, in the direction of minimum angle between the sheath section and the joint plane.
[0044] Under these conditions, the performance of the connection system can be optimum while limiting the extension of the end piece 30 B on the surface of the element 1 B in directions other than the direction in which it is genuinely necessary.
[0045] The invention is not limited to the embodiments described above. In particular, the female end piece is not necessarily incorporated into the new element that is being assembled: it can also be on the previously installed element. In another embodiment, the connecting sleeve 21 can be in one piece with the male end piece connected to the sheath section of one of the elements.
[0046] In yet another embodiment, such as that shown in FIG. 8 , the end pieces 40 A, 40 B incorporated into the two adjacent precast elements 1 A, 1 B are made up of identical parts, which allows for their production cost to be minimised and avoids confusion during the casting of the concrete elements. In this example, each end piece 40 A, 40 B has an internally threaded recess 43 capable of receiving in a sealed manner the threaded rear side of the elastic connecting sleeve 41 . Beyond this recess 43 , the end piece 40 A, 40 B ends in a frusto-conical flare 42 as previously described. Still in the example in FIG. 8 , the elastic connecting sleeve 41 has a generally M-shaped profile forming a bellows that permits both longitudinal compression and transverse offset. The arm of the M located on the front side of the sleeve 41 presses, when the elements are brought together, against the flared opening 42 of the end piece 40 A incorporated into the other element. The sealing results from the contact area between the front part of the sleeve and the frusto-conical opening 42 . In FIG. 8 , the sleeve 41 is shown at rest by dashed lines, and in its compressed position by solid lines. It will be noted that the compression of the sleeve gives rise to almost no encroachment on the inner section of the sheath, where the prestressing tendons will be threaded.
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The prestressed building structure comprises an assembly of precast elements separated by gaps occupied by an interface product, one or more prestressing sheaths having sections respectively incorporated into the precast elements, and a prestressing tendon tensioned inside the sheath. The sheath sections are respectively fitted with first and second end pieces opening out on the facing surfaces of the two precast elements. The first end piece has a flared opening. An elastic connecting sleeve is connected in a sealed manner to the second end piece. The sleeve presses against the first end piece, which compresses it longitudinally to ensure a seal between the inside of the sheath sections and the gap separating the adjacent surfaces of the two elements.
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This application is a continuation of International Application No. PCT/US03/032402 filed Oct. 14, 2003 which claims priority from U.S. Provisional Application Ser. No. 60/422,601, filed Oct. 30, 2002.
FIELD OF THE INVENTION
This invention relates to a method and apparatus integrated with a boiler for recovering sensible and latent heat from hot exhaust gas in heat exchange with cooled exhaust gas blended with oxygen for fuel combustion. The method allows the flexibility to burn virtually any fuel using oxygen-enriched air or pure oxygen and mostly CO 2 mixtures while recovering fuel sulfur as liquid SO 2 . Highest efficiency is attained in 100% O 2 /CO 2 combustion.
BACKGROUND OF THE INVENTION
References of Interest
U.S. Patents
U.S. Pat. No. 4,354,925 October 1982 Schorfheide
U.S. Pat. No. 4,542,114 September 1985 Hegarty
U.S. Pat. No. 5,732,571 March 1998 Maerz et al.
U.S. Pat. No. 6,202,574 March 2001 Liljedahl et al.
U.S. Pat. No. 6,418,865 July 2002 Marin et al.
Foreign Patent
Japanese Patent No. 50-19026 June 1973
Publications
The Steam Engine , D. Lardner; A. Hart, Philadelphia 1852, pp.73-79; First Edition London, 1827.
Argonne National Laboratories:
A. “Two-Dimensional Modeling of Fossil-Fueled Power Plant Behavior When Using CO 2 —O 2 or CO 2 —H 2 O—O 2 Mixtures, Instead of Air, to Support Combustion,” Richter et al,
June 1987, ANL/CNSV-TM-187.
B. “An Experimental Program to Test the Feasibility of Obtaining Normal Performance from Combustion Using Oxygen and Recycled Gas Instead of Air,”
ANL/CNSV-TM-204, Abele et al, December 1987.
C. “Carbon Dioxide from Flue Gases for Enhanced Oil Recovery,” ANL/CNSV-65, Sparrow and Wolsky et al,
June 1988. “Final Report on CO 2 Recovery from Power Plants.” U.S. Department of Energy, DOE/ER 30194, July 1993. “Pulverized Coal Combustion in O 2 /CO 2 Mixtures on a Power Plant for CO 2 Recovery,” Nakayama et al, Energy Conversion and Management , Vol. 33, pp. 379-386, 1992. “Experimental Studies on Pulverized Coal Combustion with Oxygen/Flue Gas Recycle for CO 2 Recovery,” Kimura et al, JSME-ASME International Conference on Power Engineering, Vol. 1, pp. 487-492, Tokyo, September 1993. “The Characteristics of Pulverized Coal Combustion in O 2 /CO 2 Mixtures for CO 2 Recovery,” Kimura et al, Energy Conversion and Management , Vol. 36, pp. 805-808, 1995. “Thermodynamic Availability Analysis for Maximizing a System's Efficiency,” T. C. Vogler and W. Weissman, Chemical Engineering Progress , pp. 35-42, March 1988. “Availability Analysis of Combustion Flue Gases-A Case Study,” M. Abu-Arabi and A. Tamimi, Energy Conversion and Management , Vol. 36, pp. 1133-1137, 1995. The Entropy Law and the Economic Process , N. Georgescu-Roegen, Harvard University Press, 1971. “What Is Heat?” G. P. Beretta and E. P. Gyftopoulos, American Society of Mechanical Engineers , Vol. 20, pp. 33-41, 1985. “Fundamentals of Analyses of Processes,” E. P. Gyftopoulos, Energy Conversion and Management , Vol. 38, pp. 1525-1533, 1997.
Oxygen enrichment of air combustion and oxygen/carbon dioxide (O 2 /CO 2 ) combustion have been studied by researchers as means to provide a greater concentration of CO 2 in the exhaust gas. The higher concentration would allow a more economical method of recovering CO 2 for sequestration, should this become necessary due to global warming of the atmosphere chargeable to excessive CO 2 buildup. See particularly Patent No. 50-19026, Japan, 1973; Argonne National Laboratories research, Richter et al, 1987 and Abele et al, 1987; and Nakayama et al, 1992. Coal-fueled power plants are considered to be at risk because their emissions generally consist of 12% to 15% CO 2 versus about 7% to 8% for gas-fueled plants when compared at similar efficiencies, for example a 10,000 Btu (10,550 kJ) heat rate per net kilowatt (kw) of power output, an efficiency of 34%. Most studies have concluded that oxygen enrichment of air combustion or O 2 /CO 2 combustion is not economical due to the high cost of purchased and delivered oxygen. Alternatively, including an air separation plant requires a relatively high capital cost and the electric power load is about 225 kw of power per ton of oxygen or approximately 20% of the total output of a 10,000 Btu (10,550 kJ) heat rate plant, using 97% to 100% purity oxygen with recycled mostly CO 2 exhaust gas as the diluent for fuel combustion. Along with other auxiliary power requirements, total parasitic power can be 25% if both CO 2 and sulfur dioxide (SO 2 ) are completely separated and liquefied for shipment or disposal, CO 2 going into an underground reservoir, for example.
Research on O 2 /CO 2 combustion in Japan, as illustrated in FIG. No. 2 , resulted in identifying an efficiency gain of 4.5% by wet recycling a CO 2 —H 2 O-rich exhaust gas through the boiler as diluent and excluding nitrogen (N 2 ), which improvement is considered due to the greater density of CO 2 compared to N 2 . Less diluent for O 2 is needed when substituting CO 2 for N 2 . However, the improvement has not been enough to justify commercialization of the technology.
Marin et al. in U.S. Pat. No. 6,418,865, for a Method For Operating A Boiler Using Oxygen-Enriched Oxidants, show data which indicate limited efficiency improvement from oxygen enrichment. The efficiency improvement is similar to the 4.5% gain found by Nakayama et al., 1992. This gain must be limited by the high moisture content in the recirculated flue gas, which has the adverse effect of increasing gas velocity through the boiler; also to system heat losses through the convection sector of the boiler and air heater and ducting; to heat losses in the processes of ash removal and flue gas desulfurization; and also due to large sensible and latent heat losses in the flue gas exhausted to the atmosphere.
The advantage claimed by Marin et al depends on the relative costs of fuel and oxygen. High cost fuel saved by low cost oxygen enrichment may yield an economic benefit. Low cost fuel and high cost oxygen enrichment may yield little or no advantage because the total efficiency improvement potential in Marin is only 4 to 5%.
The Argonne National Laboratories and Kimura et al references are instructive for elimination of NO x in O 2 /CO 2 combustion where, due to keeping most nitrogen out of the fuel combustion process, little NO x can form; and further, these studies show that any NO x formed as NO and NO 2 is about 90% eliminated by reduction to N 2 by the effect of “reburning” during the continuous recirculation of most exhaust gas as diluent for oxygen. The present invention goes further by virtually eliminating trace NO x due to gas cooling and condensing NO 2 as dilute nitric acid.
The Maerz et al patent, U.S. Pat. No. 5,732,571, is instructive for O 2 /CO 2 combustion regarding the amount of exhaust gas circulated, explaining that “approximately 80% of the flue gas employed as a substitute for the nitrogen in the air is no longer generated as exhaust gas” and therefore “it is possible to achieve a drastic reduction of the volume of flue gas to as low as 20% of the present value” compared to state-of-art plants. Patent No. 50-19026 (Japan 1973) also discloses this 80% reduction. The present invention further reduces, by half, the amount of exhaust gas for final treatment, to 10% or less, in the doubling of plant efficiency from about 34% to 68% or more, by employing the method and apparatus disclosed hereinafter.
In the preferred method of operation of state-of-art air-fired boilers, 10% to more than 20% excess air over the stoichiometric air requirement for fuel burning is utilized for temperature control and to assure good fuel burnout. The fuel penalty for excess air heating can be eliminated in O 2 /CO 2 combustion. About a 1% excess oxygen input is substituted for excess air. Combustion gas volume and space velocity are both reduced, which factors contribute to increased efficiency.
Research to find the economical and efficient O 2 /CO 2 combustion method underlying this invention has focused on attempting to measure total heat availability and also to determine the means to return known and estimated heat losses to the boiler to improve efficiency; then employing O 2 /CO 2 combustion to improve fuel burning and exhaust gas separation processes after recycling all heat in an ideal plant. The result is now found to be a state-of-art boiler without size reduction or enlargement but with most facilities removed after the superheater, which are replaced with an extension of the boiler called the Gas Primer Sector (GPS).
Sensible heat losses. Much sensible heat of combustion is wasted at several process points in state-of-art steam power plants. These losses may be 30% to 45% of the total fuel energy input. Losses are due to several factors including very high exhaust gas velocity through the radiant and convective heat transfer sectors of the boiler, 60 to 70 feet per second (fps) (18-21 mps); also to air leakage, heat radiation and insufficient insulation, and to the need to avoid corrosion at condensing temperatures. These problems are addressed in achieving this invention. Presently wasted sensible heat is virtually all recovered and returned to the boiler in the combustion gas.
Boiler moisture and latent heat losses. In the year 1763, James Watt made two discoveries which led to his development of the first efficient and economical steam engine. First he measured the expansion of water converted to steam at 212° F. (100° C.) and found that one cubic inch of water expanded to one cubic foot of steam, an expansive force of 1,728 times; and second, he discovered and measured the high latent heat of water, which force he also exploited to improve efficiency. These forces were later significant in the development of steam turbine power. They are the principal factors underlying the inefficiency problems solved by utilizing the method and apparatus disclosed hereinafter. Water-to-steam expansion is essential on the steam side of the boiler tubing where pressure is developed to turn the turbine to provide power. But on the combustion-and exhaust side of the boiler tubing, fuel moisture and combustion air moisture plus fuel hydrogen oxidized to H 2 O cause conditions detrimental to efficiency: first by raising the velocity of gases passing through the boiler, thus reducing residence time for fuel combustion and for radiant heat transfer through the tubing; and second, because state-of-art boilers are operated to exhaust flue gases at above 212° F. (100° C.) and more generally at 240-450° F. (116-232° C.) to avoid acid gas corrosion at condensing temperatures. All latent heat of vaporization/condensation is lost, wasted to the atmosphere. Depending on the fuel burned, whether natural gas, oil, coal, petroleum coke, lignite or a synthetic fuel, and depending on the air moisture content, latent heat losses may be 7% to 15% of the fuel energy input. My improved method and apparatus embody the means to recover most of the latent heat to increase efficiency.
Wet scrubbing processes have been developed which are capable of removing sulfuric acid and most SO 2 from flue gas. The stack gas temperature for emission may be less than 212° F. (100° C.) if corrosion-resistant materials are used for ducting and to line the stack. However, a large amount of sensible heat and all latent heat is absorbed in the alkaline scrubbing slurry and is not recoverable to improve combustion efficiency.
Combined-cycle power generation. Water-to-steam expansion has been important in raising the efficiency of aeroderivative turbines in combined-cycle systems where a turbine plus a heat recovery steam generator (HRSG) are now able to achieve better than 50% efficiency. An important efficiency gain came from reducing the approximately 300% excess air requirement of the turbine by partial substitution of water or steam. A greater expansive force results from the substitution because water vapor has approximately a 60% greater space requirement than air (see Table 1, H 2 O:Air, cu ft/lb). The >50% combined-cycle efficiency is an important improvement versus single-cycle turbine-only power generation. However, much high-purity water is required, all lost to the atmosphere along with all fuel combustion condensate. Also, the very high velocity of the turbine exhaust gas flowing through the HRSG limits useful heat recovery so that much sensible heat and all latent heat is lost to the atmosphere. Combined-cycle power generation generally requires a NO x reduction catalyst which has high operating costs. Compare the combined-cycle combustion method with the technology described hereinafter which has no need for catalysts, which is a net producer of water by recovering and processing all condensate, which should have a higher efficiency, and which is not restricted to natural gas or a clean syngas as operating fuel.
The efficiency improvements found in the research for this invention are due to many factors. The key was finding an economical way to remove most of the moisture from the exhaust gas to allow the heat transfer advantages of the O 2 /CO 2 combustion method to become obvious. This will be apparent from examination of Table 1 that appears hereinafter. If gas velocities, both combustion gas and exhaust gas, are sufficiently reduced, complete fuel burn-out is attainable and better heat transfer is achieved in longer boiler residence time. Adding the insulated GPS to the boiler provides the means to recover the remaining sensible heat and most latent heat by indirect counterflow heat exchange of outflowing exhaust gas with inflowing O 2 /CO 2 combustion gas in a long residence time, 15 to 45 seconds or more. If CO 2 is substituted for N 2 as the diluent for oxygen in fuel combustion, O 2 concentration can be increased more than 60% due to CO 2 having a density and heat capacity 63% greater than N 2 . Schorfheide, in U.S. Pat. No. 4,354,925, explains that over a temperature range of 800 to 980° F. (427-527° C.) (for coke burning to regenerate a catalyst), “carbon dioxide has an average heat capacity 63 percent greater than that of nitrogen (12.1 Btu/lb mol-° F. for CO 2 versus 7.43 Btu/lb mol-° F. for nitrogen) . . . carbon dioxide will absorb roughly 63% more heat than an equivalent volume of nitrogen at corresponding temperatures.” Also “the concentration of oxygen can be about 63 percent greater in the case of complete carbon dioxide” and this O 2 /CO 2 mixture “reduces burn time by a full 33 percent.”
If the exhaust gas is cooled to ambient or below in an extended residence time, nitrogen oxide (NO) will oxidize to nitrogen dioxide (NO 2 ) in a slight excess of O 2 (see Hegarty, U.S. Pat. No. 4,542,114) and will convert to nitric acid (HNO 3 ) and drop out as condensate. Sulfur trioxide (SO 3 ) will convert to sulfuric acid (H 2 /SO 4 ) and also drop out as condensate. If most moisture is condensed, blower power to move the much drier, cool exhaust gas is reduced. Blower power to move cool recycled combustion gas is also reduced. If a relatively dry <1% moisture content O 2 /CO 2 combustion gas is then reheated and returned to the boiler, the velocity of the combustion gas through the boiler is sharply decreased.
CO 2 has a much greater density than H 2 O. CO 2 :H 2 O=44:18=2.44 or CO 2 has 244% of the density and sensible heat capacity of H 2 O as water vapor by mol wt. In the wet recycle O 2 /CO 2 —H 2 O method, the exhaust gas is returned to the boiler with no moisture reduction which has the undesired effect of reducing heat capacity and sharply raising velocity. This reduces combustion gas residence time which impairs radiant heat transfer through the boiler heating surfaces. The velocity problem in the wet recycle method obscures most of the efficiency improvement opportunity related to substituting denser CO 2 for N 2 as diluent.
If a vacuum removal method can be utilized to take out particulate in a low velocity non-turbulent laminar flow heat exchange duct, no electrostatic precipitator (ESP) or baghouse is needed. If heavy insulation can be economically used to retain heat for exchange in a duct system with a low velocity combustion gas flow of blended O 2 and CO 2 , then virtually 100% of the so-called waste heat lost in state-of-art combustion systems can be returned to the boiler. If most sensible and latent heat can be recycled to benefit fuel combustion, the plant fuel requirement, the oxygen requirement, the plant parasitic power requirement and the CO 2 output may all reduce by half; and potentially more than half since most state-of-art air-fired steam generation power plants operate at net efficiencies of only 33% to 35%.
If the final exhaust gas of the O 2 /CO 2 combustion process is cooled to ambient temperature or below, the volume for cleanup and separation will be less than 10% of the hot flue gas output from a state-of-art air-fired steam power plant. Gas separation and the recovery of constituents will be economical by known means. Corrosion in the condensing region is not a disabling problem due to the development and proven reliability of superaustenitic stainless steels. Condensate may be recovered and processed to boiler feedwater or potable water quality. Trace mercury fume is captured in a filter by activated carbon or other known sorbents. SO 2 is recovered as a refrigeration-grade liquid for chemicals production or feedstock to a sulfuric acid plant. If a sulfuric acid plant is added, the particulate recovered from fuel combustion can be chemically processed in an acid-leaching treatment for metals recovery and upgrading of the remainder particulate.
The foregoing discussion considers most of the changes necessary to maximize efficiency in O 2 /CO 2 combustion with 97% to 100% pure oxygen, which changes have been incorporated into the preferred embodiments described in detail hereinafter.
Partial oxygen enrichment of air combustion . Air combustion with oxygen enrichment, in a boiler combined with the GPS and with moisture mostly removed from the recycled exhaust gas, has been studied. 30% or more enrichment will provide good efficiency improvement compared to complete air combustion but less than with pure oxygen. This is because of the added nitrogen and also due to air moisture of several percent which varies with ambient air conditions. By increasing the amount of lower density nitrogen displacing CO 2 in the recycling of exhaust gas to the boiler and by the addition of air moisture, gas flow volume and velocity are increased and therefore reduce residence time for heat transfer, lowering efficiency below complete O 2 /CO 2 combustion.
Air combustion of clean fuels . Combining the GPS with a boiler allows air combustion of clean fuels with only trace NO x in the emission. Efficiency is improved compared to state-of-art air-fired combustion steam generation plants. This is a once-through process with no exhaust gas recycling which uses the heat exchange method and apparatus of the GPS to condense most moisture and increase waste heat recovery. The exhaust gas temperature is reduced to about 40° F. (4° C.). The presence of an excess of oxygen at this reduced temperature with an extended residence time provides the conditions to convert NO to NO 2 which then is recovered as dilute nitric acid (HNO 3 ) condensate. The final exhaust gas will contain less than 1% moisture in a mixture of mostly N 2 , CO 2 and O 2 . Condensate may be treated to boiler feedwater or potable water quality.
SUMMARY OF THE INVENTION
Rankine cycle steam power plants may be adapted to a high efficiency and low emission combustion method by replacing most facilities after the superheater. The economizer section is reconfigured. Eliminated are the air heater, ESP or baghouse, and flue gas desulfurization (FGD) by scrubbing, all three of which dissipate heat, most of which is now recovered by the improved method and apparatus disclosed hereinafter.
Highest efficiency will be attained in a combustion gas atmosphere of a largely moisture-free mixture of pure oxygen and carbon dioxide.
A GPS is combined with a boiler to reduce the exhaust gas temperature, velocity, particulate and moisture. The exhaust gas temperature is reduced to ambient or below while the return flow combustion gas temperature is raised from ambient. Integration of the GPS with the boiler makes possible the maximum preheating of an optimally controlled mixture of O 2 and CO 2 combustion gas.
The exhaust gas and the combustion gas flows are through corrosion-resistant outer and inner superaustenitic stainless steel ducts. Most particulate in the exhaust gas drops out in the reduced velocity non-turbulent laminar flow for vacuum removal. The ducts are sized to provide an extended residence time for both the combustion gas and exhaust gas flows. The low velocity and laminar flow of the exhaust gas will beneficially promote the van der Waals force effect, which is the coalescing and agglomeration of fine particles; and the slow gas flow will benefit particulate settling by the force of gravity.
Hydrocarbon fuels may contain up to several percent sulfur and 1% nitrogen. These elements oxidize during combustion and in the presence of H 2 O they are the source of acidic moisture. Most acidic moisture is condensed; trace sulfur trioxide (SO 3 ) condenses as dilute sulfuric acid (H 2 SO 4 ) and trace nitrogen oxide (NO) converts to nitrogen dioxide (NO2) and condenses as dilute nitric acid (HNO 3 ). Other trace acids, hydrochloric (HCl) and hydrofluoric (HF) may be present depending on the fuel and will also condense.
Most exhaust gas is recirculated to the boiler blended with oxygen to comprise the fuel combustion gas via one or more return ducts within the insulated GPS for nearly 100% recovery of sensible heat and recovery of most latent heat, to reduce the fuel and oxygen consumption of the combustion process. Exhaust gas may also be ducted back to the boiler and reheated via the GPS for attemperation duty and also to convey pulverized or crushed or shredded fuels into the boiler.
The preheated largely moisture-free and mostly O 2 and CO 2 combustion gas with low excess O 2 (no greater than about a 3% excess and preferably about 1% excess of stoichiometric) allows a low velocity of 20 to 30 fps (6-9 mps) through the boiler and therefore a long fuel combustion residence time with much greater heat conduction compared to high velocity 60 to 70 fps (18-21 mps) air-fired boilers usually operated with 10% to 20% or more excess air. Operation of the boiler for temperature control with a well modulated mixture of relatively dry (<1% moisture) O 2 /CO 2 combustion gas at 20 fps (6 mps), versus 60 fps (18 mps) for open-cycle air combustion, triples fuel combustion and heat transfer time. Furthermore, combustion in an O 2 /CO 2 gas mixture versus air combustion at the same temperature reduces burn time by 33% due to the greater density and heat capacity of CO 2 compared to N 2 . The sum of these two advantages approximately quadruples the net effective radiant heat transfer time in the boiler. These fuel combustion conditions, together with the nearly complete heat recovery achieved by combining the GPS with the boiler, explain most of the previously unpredictable high efficiency of this O 2 /CO 2 combustion system.
The remainder exhaust gas not recirculated to the boiler is ducted at ambient temperature to be further processed by known means to condense and remove any remaining acidic moisture. The mildly acidic condensate is processed by known means to boiler feedwater or potable water quality. Remainder particulate in the exhaust gas is dry-filtered. Mercury fume carried over from the fuel is captured in a filter by activated carbon or other known sorbents. The exhaust gas is further processed to liquify SO 2 and then may be processed to liquify CO 2 with any trace N 2 and O 2 vented to the atmosphere. Sulfur-free fuels require fewer processing steps.
Boilers integrated with the GPS may be operated with partial oxygen enrichment of air to obtain an efficiency improvement with reduced emissions. 30% or greater enrichment is preferred to keep nitrogen at moderate levels. Too much N 2 adversely affects both combustion gas and exhaust gas volume, velocity, residence time and heat transfer.
Boilers integrated with the GPS may also be operated without oxygen enrichment of air when firing natural gas or sulfur-free synthetic fuels and will deliver improved efficiency with very low nitrogen oxides (NO x ) in the emission because moisture condensation traps virtually all NO x as dilute HNO 3 in the recovered condensate.
Fuels eligible for combustion in either the O 2 /CO 2 or the oxygen-enriched method and apparatus of this invention include most refuse-derived fuel (RDF), biomass and most combustible hazardous wastes but excluding radioactive materials. The limiting factor is maintaining boiler temperature. Low Btu fuels such as RDF and biomass may be blended with coal, petroleum coke, natural gas or heavy fuel oil, for example, and boiler temperature will be controlled by adjusting the proportion of diluent to oxygen in the combustion gas. Slagging fuels can limit boiler selection. Boilers equipped with cyclone furnaces are designed for slag recovery. Fluidized bed boilers are not felt to be suited to the combustion method of this invention. In fluidized bed combustion, fuel sulfur is largely captured by sorbents such as crushed limestone. Massive solid wastes are produced. In my preferred method, sulfur recovery is accomplished by liquefying SO 2 , a feedstock for manufacturing many chemicals including sulfuric acid. The higher capital and operating costs of fluidized bed combustion boilers are unnecessary for either O 2 /CO 2 or oxygen-enriched air embodiments employing the method and apparatus of this invention.
The application of variable speed drive (VSD) controlled motors is preferred and has three cost-reducing functions: (1) VSD minimizes the parasitic power requirement wherever applied; (2) the process-gas flows, both exhaust gas and combustion gas flows, may be continuously optimized; and (3) applying VSD to all system-variable process flows makes possible the mostly complete automation of the combustion method and apparatus of this invention.
In one particular aspect, the invention provides a Rankine cycle steam generator system which system comprises: a boiler ( 1 ) having a fuel combustion zone ( 1 a ) and radiant heat and convective heat transfer zones ( 2 , 3 ) for producing steam; an insulated Gas Primer Sector (GPS) ( 4 ) combined with the boiler so that an exhaust gas stream therefrom flows through the GPS; the GPS including means ( 29 ) for removing particulate from the exhaust gas stream and means ( 5 ) for transferring heat to a combustion gas stream by indirect counterflow heat exchange with the exhaust gas stream over an extended residence time, the result of which heat transfer is the reduction of the temperature of the exhaust gas stream to a temperature where moisture condenses; means ( 12 ) for supplying said combustion gas stream to the GPS where it is heated in indirect counterflow heat exchange with the exhaust gas stream over an extended residence time to reach a temperature of at least about 500° F. (260° C.); insulated duct means ( 6 ) for conveying the heated combustion gas stream exiting the GPS to the boiler combustion zone ( 1 a ) for fuel combustion therein; and means for removing particulate from the GPS.
In another particular aspect, the invention provides a Rankine cycle steam generator system which system comprises: a boiler ( 1 ) having a fuel combustion zone ( 1 a ) and radiant heat and convective heat transfer zones ( 2 , 3 ) for producing steam; an insulated Gas Primer Sector (GPS) ( 4 ) combined with the boiler so that an exhaust gas stream therefrom flows through the GPS; said GPS including means ( 29 ) for removing particulate from the exhaust gas stream and means ( 5 ) for transferring heat to a combustion gas stream that includes oxygen and mostly CO 2 by indirect counterflow heat exchange with the exhaust gas stream over an extended residence time, as a result of which heat transfer the temperature of the exhaust gas stream is reduced to near ambient or lower so that moisture condenses; means ( 14 ) for further cooling the exhaust gas stream to between about 32 and 50° F. (0-10° C.); means ( 9 , 17 ) for separating the further cooled exhaust gas stream into a first major portion and a second portion; means ( 8 , 11 , 12 ) for combining said first portion with O 2 to form the combustion gas stream and for supplying same to the GPS where it is heated in indirect counterflow heat exchange with the exhaust gas stream over an extended residence time to reach a temperature of at least about 500° F. (260° C.); insulated duct means ( 6 ) for conveying the heated combustion gas stream exiting the GPS to the boiler combustion zone ( 1 a ) for fuel combustion therein; and means ( 29 ) for removing particulate from said GPS.
In a further particular aspect, the invention provides a method for operating a Rankine cycle steam generator system which system includes a boiler ( 1 ) having a fuel combustion zone ( 1 a ) and radiant heat and convective heat transfer zones ( 2 , 3 ) for producing steam, and an insulated Gas Primer Sector (GPS) ( 4 ) combined with the boiler so that an exhaust gas stream therefrom flows through the GPS and wherein a combustion gas stream flows in a counterflow direction therewithin, said method comprising transferring heat to the combustion gas stream by indirect counterflow heat exchange with the exhaust gas stream over an extended residence time within the GPS, as a result of which heat transfer the temperature of the exhaust gas stream is reduced to near ambient or lower so that moisture condenses; removing particulate from the exhaust gas stream in the GPS; further cooling the exhaust gas stream to between 32 to 50° F. (0-10° C.) to condense additional moisture; separating the further cooled exhaust gas stream into a first major portion and a second portion; combining the first portion with O 2 to form a combustion gas stream containing O 2 and mostly CO 2 and supplying same to the GPS where it is heated in indirect counterflow heat exchange with the exhaust gas stream over an extended residence time so that it reaches a high temperature of at least about 500° F. (260° C.); conveying the high temperature combustion gas stream from the GPS through insulated duct ( 6 ) to the boiler combustion zone ( 1 a ) for fuel combustion therein and removing particulate from the GPS.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of a state-of-art air-fired boiler system with flue gas cleaning processes.
FIG. 2 is a schematic view of an O 2 /CO 2 —H 2 O-fired boiler system with exhaust gas cleaning processes and with SO 2 and CO 2 liquids recovery, according to Nakayama et al., 1992.
FIG. 3 is a schematic view of an O 2 /CO 2 -fired boiler system combined with a Gas Primer Sector (GPS) and with SO 2 and CO 2 liquids recovery as described in my preferred embodiments.
FIG. 4 is a schematic view of a cross-section of the upper ducts of the GPS at point A of FIG. 3 showing particulate recovery by vacuum blowback filters.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 3 shows a cross-sectional schematic diagram of a steam-generating boiler 1 combined with a Gas Primer Sector (GPS) 4 . Boiler 1 includes a fuel combustion zone 1 a , radiation zone 2 and a convection zone in the area of the boiler feedwater tubing 3 . Fuel is supplied to the boiler in the lower region of radiation zone 2 , and the fuel oxidant is delivered through an insulated duct 6 .
The overall dimensions of the GPS are generally proportional to boiler size. For example: given a 100 MW scale state-of-art boiler designed by Babock & Wilcox, its height may be about 125 feet (38 m); the GPS may extend horizontally about 125 feet (38 m) from the top of the boiler, then downwardly about 125 feet (38 m), and again horizontally about 75 feet (23 m) in a lower gas cooling section, as illustrated in FIG. 3. A similar boiler designed for a 750 MW capability may have a height of 250 feet (76 m); the GPS may extend horizontally about 250 feet (76 m) from the top of the boiler, then downwardly about 250 feet (76 m), and again horizontally about 150 feet (46 m).
The boiler start-up oxidant may be air entering the system through blower through ducts 26 and 12 . When the oxygen supply for normal closed-cycle operation of the boiler reaches the required rate, air supply duct 26 is closed. Complete O 2 /CO 2 combustion will eventuate, as exhaust recycling continues with O 2 blending and the nitrogen from initial air admission is gradually winnowed from the exhaust.
Boiler start-up fuel is preferred to be natural gas or a synthetic fuel to minimize the emission from open-cycle operation. This emission may include a small amount of NO x as N 2 O (nitrous oxide), NO and NO 2 . The GPS 4 includes an insulated, elongated outer duct and one or more elongated inner ducts 5 . As best seen in FIG. 4 , the elongated interior duct is generally coaxial with the exterior duct and has a sloped upper surface to deter the accumulation of particulate. The oxidant is blown through a duct or ducts 5 interior of the insulated Gas Primer Sector 4 and then through the insulated duct 6 to the lower boiler fuel combustion zone. The duct or ducts 5 are constructed of corrosion-resistant thin-walled superaustenitic stainless steel in order to effect maximum heat transfer of outflowing exhaust gas to the inflowing oxidant combustion gas. A superaustenitic stainless such as the AL-276 metal available through Allegheny Technologies is preferred. Al-276 is corrosion-resistant to the acidic high-temperature environment of the GPS 4 . This metal has a maximum operating temperature of 1000° F. (538° C.) and is therefore suited to corrosive outflowing exhaust gas conditions following the boiler feedwater heating zone 3 where the temperature will be about 800° F. (427° C.) decreasing to 70 to 120° F. (21-49° C.) at the base of the vertical section of the GPS 4 . Duct 5 may be constructed on a suspended metal frame to hold in place welded stainless steel sheets of about {fraction (1/16)}″ (0.15 cm) thickness. The thinnest sheeting which can be securely welded, to prevent leakage from the inner duct 5 combustion gas into the outer duct, is preferred so as to maximize heat transfer from the outflowing exhaust to the cooler inflowing combustion gas. AL-276 thermal conductivity is approximately 9.8 Btu's/ft 2 /hr/° F./ft at 800° F. exhaust gas temperature, decreasing to 6.4 at 200° F. and to 5.9 Btu's at 70° F. (17 W/m/° K at 427° C., 11 at 93° C. and 10.2 at 21° C.).
The outer duct of the GPS 4 is well insulated. The insulation efficiency is preferred to exceed 90% and most preferred to be 98 to 99% efficient. Construction materials may include an insulation-grade concrete of up to three feet thickness to maximize heat retention, plus an inner liner of superaustenitic stainless steel to prevent corrosion.
Following boiler start-up, exhaust gas passes upward through the boiler radiant heat zone 2 , transferring heat to the boiler tubing to produce steam. It then passes the convection zone 3 to further transfer heat through tubing for boiler feedwater heating, thereby reducing the exhaust gas temperature from about 1800-2000° F. (982-1093° C.) to about 800° F. (427° C.)at about the location of entry into the GPS 4 . The GPS 4 comprises an upper generally horizontal section, an intermediate generally vertical section and a lower generally horizontal section that may be aligned below the upper section. The outflowing exhaust gas temperature gradually reduces preferably to about 200° F. (93° C.) or below at the end of the horizontal upper duct section, then further reduces to preferably about 70-120° F. (21-49° C.) at the base of the vertical duct section, more preferably to about 70° F. (21° C.). Mildly acidic moisture condenses and leaves the air-tight GPS through a collection basin and line 16 . The exhaust gas is further cooled in zone 13 of the GPS that is preferably equipped with refrigerant cooling coils 14 . The exhaust gas temperature is reduced to below 50° F. (10° C.) and preferably to at least about 40° F. (4° C.) to further condense acidic moisture, which leaves the system via line 15 . Most remaining particulate precipitates in the condensate in the low velocity laminar gas flow of cooling zone 13 .
For a short period of time during boiler start-up, the major portion of this cooled, nearly moisture-free exhaust gas is routed through a duct 9 and a blower 10 , then through a duct 11 for blending with air and with some oxygen from an air separation unit 7 , incoming flow of which is controlled by a blower 38 having a variable speed drive (VSD) motor that delivers the O 2 through duct 8 . As the combustion system begins operation, such mixing of the flows from ducts 11 and 8 and some air takes place, and this combination gas mixture is routed back to the GPS through duct 12 . A small stream of excess exhaust gas is routed through a duct 17 and a blower 18 through a line 23 to the stack 24 .
Provided that the boiler fuel is sulfur-free natural gas or synthetic fuel, open-cycle air combustion may be continued with only minimum NO x emissions due to the exhaust cooling method of the GPS wherein NO is oxidized to NO 2 which cools and in the presence of trace oxygen, condenses as HNO 3 in an extended residence time. Efficiency is improved versus state-of-art open cycle air combustion due to the heat recovery method of the GPS.
In the most preferred method of operation, and regardless of the fuel, the boiler combined with the GPS will reach maximum efficiency with complete O 2 /CO 2 combustion as shown in Table 1 (5), the recycled diluent being >95% CO 2 . Air is excluded and only the nitrogen that may be present in the fuel is passing through the system. Nitrogen conversion to NO x will be extremely low and after HNO 3 condensation in cooling region 13 , NO x may not be detectable.
TABLE I
Principal Exhaust Gas Constituents of a Pulverized Coal-Fired Boiler
for Air Combustion, for O 2 /CO 2 —H 2 O Combustion and for O 2 /CO 2
Combustion
Weight Percent by
Volume
Method of Combustion(2)
Mol.
Specific
Cu. Ft.
O 2 /
O 2 /
Gas
Wt.(1)
Gravity
Lb.(1)
Air(3)
CO 2 —H 2 O(4)
CO 2 (5)
H 2 O
18.106
1.0
21.004
10.0%
40.0%
<1.0%
N 2
28.106
1.555
13.46
72.0
<1.0
<1.0
Air
28.975
1.600
13.069
—
—
—
O 2
32.00
1.776
11.816
3.0
<2.0
1.0
CO 2
44.00
2.442
8.593
15.0
56.0
>95.0
SO 2
64.06
3.556
5.901
0.25
1.5
2.5
(1)Compressed Air and Gas Handbook, 1988, water vapor et al at 60° F., 14.7 lb.abs.
(2)Generalized estimates. Fuel: bituminous coal, 3% sulfur.
(3)Estimated at the air heater outlet, 300° F. or more.
(4)Estimated at the flue gas recycle fan, 250-450° F.
(5)Estimated at the exit of the Gas Primer Sector (GPS), 40° F.
After fuel combustion in the radiant heat zone of the boiler, hot exhaust gases carry particulate upward and into the horizontal region of the GPS; the gas stream exiting the boiler is preferably at a velocity of about 30 fps (9 mps) or less and more preferably at about 20 fps (6 mps) or less. Here most particulate drops out in a low velocity and long residence time laminar gas flow as the hot outflowing exhaust gas cools by indirect heat exchange with the counterflowing O 2 /CO 2 combustion gas in duct 5 . The outflowing gas continues to cool as it passes downward and moisture condenses, further removing particulate in the condensate. Most remaining particulate will be captured in condensate as the exhaust gas passes through cooling zone 13 where the final exhaust gas temperature may be reduced to about 32 to 50° F. (0-10° C.), and preferably to about 40° F. (4° C.), and its velocity is reduced to about 10 fps (3.3 mps) or less. The major portion of the cooled exhaust gas (with its moisture reduced to <1%) is passed through duct 9 , blower 10 and duct 11 to be blended with O 2 ; this blend flows through duct 12 at about ambient temperature and enters the interior duct or ducts 5 within the GPS. The blended O 2 /CO 2 combustion gas is heated to 500-750° F. (260-399° C.), and preferably to at least about 700° F. (382° C.) in its indirect counterflowing, low velocity and long residence time heat exchange with the outflowing exhaust gas.
Outflowing exhaust gas residence time through the GPS 4 is preferred to be 15 to 45 seconds and more preferably at least about 30 seconds. Inflowing combustion gas residence time through the GPS 4 and duct 6 and boiler 1 is preferred to be 15 to 45 seconds and more preferably at least about 30 seconds.
In this most preferred embodiment of the method and apparatus of this invention, the excess exhaust gas that is not recycled to the boiler passes through duct 17 and blower 18 , and then through a duct 19 leading to gas finishing processes, which processes are carried out by known means. The preferred means include passing the now ambient temperature exhaust gas through a compressor and a cooler to remove any remaining moisture; then passing the dry gas through a filter if desired to reduce any remaining particulate to below one micron particle is size; then passing the gas through a sorbent filter such as activated carbon to remove mercury fume if such is present; then reducing the gas temperature to at least about 70° F. (21° C.) in a unit 20 that includes a heat exchanger and recovering liquid SO 2 which will condense therein; and finally either passing the remainder through a duct 21 for further cooling by known means, preferably a gas/liquid heat exchanger 22 , to liquify CO 2 , or alternatively ducting the gaseous CO 2 through line 23 to stack 24 for release to the atmosphere.
In the most preferred processes, in units 20 and 22 , the exhaust gas is compressed to 100-450 psi (6.9-31 bars) and cooled to condense SO 2 ; and then may be further cooled to about −30° F. (−34° C.) for storage, where any N 2 or O 2 contained in the CO 2 will boil off to be vented. Stored liquid CO 2 and also liquid SO 2 are available for refrigeration duty to cool an intermediate refrigerant which in turn may be used to cool plant condensers and heat exchangers.
The exhaust gas polishing steps including blower 18 and the compressor would need to have less than 10% of the mass flow capacity of a comparable size air-fired boiler due to the following factors: treatment of a much-reduced volume of cool gas, at ambient temperature, versus hot flue gas at 200-450° F. (93-232° C.); reduced fuel consumption further reduces both combustion gas and exhaust gas flows; about 1% excess O 2 is substituted for 15-20% or more excess air; and higher density/higher heat capacity CO 2 replaces N 2 and water vapor as the recycled diluent in the combustion gas so that the final product to be treated is >95% CO 2 .
The O 2 /CO 2 combustion method and apparatus of this embodiment may embody additional ducts and blowers depending on the choice of boiler fuel and preferred operating technique. Solid fuels are preferably pulverized, crushed or shredded. This closed-cycle system desirably employs recycled gas to blow fuel into the boiler to exclude blowing with air, with its nitrogen content, which would reduce boiler efficiency. FIG. 3 shows a blower 27 which would connect to a duct, not shown, to carry a controlled amount of exhaust gas through the GPS via a duct 36 (see FIG. 4 ) for heating to 500-750° F. (260-399° C.) and then through an insulated duct, not shown, paralleling combustion gas duct 6 , to the location of a pulverizer or crusher or shredder, not shown, from where such hot gas blows is heated fuel into the boiler.
A blower 28 may also be provided to move exhaust gas through a duct, not shown, leading to the GPS 4 to provide upper boiler exhaust gas attemperation as a means to avoid ash fusion temperatures above about 2200° F. (1204° C.). By this means, upper boiler and convective zone temperatures can be maintained at about 2000° F. (1093° C.) to prevent efficiency-limiting particulate accumulations on the radiant and convective heat transfer tubing surfaces. This duct may also be routed through the GPS (see duct 37 in FIG. 4 ) if it is preferred to utilize hot exhaust gas, largely CO 2 , for attemperation at 500-750° F. (260-399°). Or alternatively, ambient temperature exhaust gas can be routed through blower 28 through a duct, not shown, without preheating for injection into the upper boiler area. In either instance, this attemperation gas stream preferably contains less than 1% moisture. Preferably attemperation is controlled by a VSD blower using exhaust gas containing mostly CO 2 and generally more than 95% CO 2 .
A flexible and readily variable method of operating the O 2 /CO 2 combustion processes of this invention takes advantage of a simplified and preferred operating scheme utilizing variable speed drive (VSD) motors for the key blowers in the system, namely blowers 10 , 18 , 27 , 28 and 38 , to achieve precise management from a single control point. As earlier indicated, overall management of the character of the combustion gas stream preferably achieves a relatively low velocity exhaust gas stream, e.g. 20 to 30 fps, through the boiler. Particulate vacuum pumps, water and other pumps are controlled separately.
System pressures for the preferred operating methods of this invention will be low, from a few pounds through the boiler radiant heat zone 2 and gradually reducing to a slight vacuum in cooling region 13 of the GPS as the outflowing exhaust gas cools and moisture condenses. Boiler radiation zone 2 pressure may be 2 to 50 psi (0.13 to 3.3 bar) but will preferably be maintained in the range of 5 to 15 psi (0.3 to 1.0 bar). Pressure is controlled by adjusting the speeds of blowers 10 and 18 .
FIG. 4 shows a cross-section of the ducts in the upper section of the GPS 4 at, for example, point A on FIG. 3 . This cross-sectional view shows a large duct to transport combustion gas to the boiler. Small ducts 36 and 37 have been discussed is above. A bottom plate 30 in the outer duct is made of perforated superaustenitic stainless steel and allows passage of settled particulate. When vacuum pumps/blowers 31 are activated, particulate passes through ducts 29 to exit the GPS; operation may be intermittent, as needed. Such particulate and hot gas passes into ash separation units 32 , which may be placed about every 10 to 15 feet (3.3-4.6 m) along the horizontal upper zone of the GPS 4 . Filters 33 collect particulate, and hot exhaust gas is blown back through lines 34 . This blow-back gas force acts to dislodge particulate which may accumulate on duct 5 and on the boiler feedwater heating tubing 3 . Reverse pulse operation of blowers/pumps 31 cleans filters 33 , and the particulate drops through lines 35 for recovery.
Table 1 cites data related to underlying causes of poor efficiency in Rankine cycle air-fired combustion systems, which problems are largely overcome in a closed single-cycle O 2 /CO 2 combustion method (5). Water vapor has a low specific gravity/low density compared to CO 2 . The heat capacity of CO 2 is 2.44 times the sensible heat capacity of H 2 O as water vapor by molecular weight. The high water vapor in (3) and (4) causes large latent heat losses, 970 Btu/lb (540 cal/g) H 2 O, in addition to the sensible heat losses which are found by measuring the exhaust gas mass flow at the air heater outlet where temperatures are typically 300° F. (149° C.) or more. The sensible heat loss is 1.0 Btu/lb-° F. for H 2 O, 1.56 Btu/lb-° F. for N 2 and 2.44 Btu/lb-° F. for CO 2 (4.15 kJ/kg-° C. for H 2 O, 6.48 kJ/kg-° C. for N 2 and 10.14 kJ/kg-° C. for CO 2 ) at atmospheric pressure and system mini-mum temperatures, in accordance with the molecular weights and specific gravities in Table 1. The latent and sensible heats are unavailable for steam generation in (3). Latent heat is not recovered in (4) but sensible heat is partially recovered. Both latent and sensible heats are largely recoverable in (5). The low density of water vapor causes high velocity and therefore poor heat transfer. The gas space requirement of water vapor compared to CO 2 is 21 ÷8.59 (1) or 2.44 times CO 2 . N 2 in (3) adversely affects velocity compared to (4) and (5). Maximum use of CO 2 with minimum water vapor and N 2 in (5) minimizes volume and space velocity for the best heat transfer results in both the exhaust gas and the recycled combustion gas.
A sulfur removal alternative to condensing SO 2 in the unit 20 is the is injection of calcium oxide (CaO) or other alkaline sorbents dissolved in water to react with SO 2 to form salts, which is a well-known flue gas scrubbing method. Injection may be by spraying the solution into the GPS 4 at the top of the vertical section. The falling alkaline mist will absorb and precipitate the salts at exhaust gas temperatures decreasing from about 200° F. (93° C.) at the top to about 70° F. (21° C.) at the bottom in a low exhaust gas velocity of 10 to 15 fps (3.3-4.6 mps). Further condensation occurs in the cooling region 13 where the exhaust gas temperature is reduced to about 40° F. (4° C.) with a <1% moisture content. The final exhaust gas will contain only trace amounts of SO 2 and any formed acids. Therefore the exhaust gas may be safely vented without utilizing the compression and cleanup methods of unit 20 . This alternative method may be employed during any interruption of the processes in unit 20 . Also it may be utilized continuously when burning low-sulfur fuels. For example, most coals in Montana and Wyoming in the western United States, and also many lignites, contain natural SO 2 sorbents and only 0.25% to 0.50% sulfur, and this method may satisfactorily replace unit 20 when there is low SO 2 content, the recovery of which would have insignificant commercial value. The drawback to this removal method is reduced efficiency due to the injected water spray which greatly reduces sensible heat recovery and mostly eliminates the possibility of latent heat recovery. Also the volume of solid wastes to be disposed of is increased.
There has been disclosed herein a method for operating a boiler together with an apparatus integrated with the boiler to achieve significant efficiency improvement with reduced emissions. The invention has been described and illustrated by specific embodiments but is not to be so limited. Those skilled in the art will understand that variations and modifications can be made without departing from the spirit of the invention, and it is intended that such variations and modifications shall be considered to be within the scope of the appended claims and equivalents thereof.
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A method and apparatus to conduct 0 2 /CO 2 combustion or oxygen-enriched combustion. The boiler exhaust gas passes through a Gas Primer Sector (GPS) combined with the boiler to effect heat transfer to the combustion gas in indirect counter-flow heat exchange. Sharply reduced gas flows result from using largely moisture-free CO 2 as diluent for O 2 in the combustion gas which allows long residence time at low velocity for maximum heat transfer from the exhaust gas to the combustion gas. Most particulate drops out and most moisture is condensed from the cooled mostly CO 2 exhaust gas. The larger portion is blended with oxygen for the combustion gas and reheated and returned to the boiler through the integrated GPS; the smaller portion is cleaned and separated, the CO 2 released or recovered. The complete exhaust gas-combustion gas cycle may be 30 to 90 seconds and preferably about 60 seconds. The high heat capacity of CO 2 allows a much higher oxygen content in the combustion gas compared to open-cycle air combustion with a large nitrogen content of lower heat capacity. Efficiency is increased. Final exhaust gas separation and recovery is simplified. Condensate is processed to boiler feedwater or potable water quality. NO x , is eliminated, mercury fume captured and CO 2 output reduced.
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This application is a continuation-in-part of U.S. Ser. No. 07/799,901, filed Nov. 26, 1991, now abandoned which is a continuation of U.S. Ser. No. 07/530,638, filed May 30, 1990 now abandoned.
This application is related to application Ser. No. 07/406,727, filed Sep. 13, 1989.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process of and apparatus for molding a thermoplastic sheet and is applicable, e.g., to a blister package used for packaging foods, daily needs, medicines and the like.
2. Description of the Related Art
Recently, the so-called blister package has been employed, in which a resin sheet is molded to have a pocket adapted to the shape of a content of the package, e.g., a medicine and contained it therein and subsequently seals the pocket.
Heretofore, polyvinylchloride (PVC) has been predominantly employed as a material for the above resin sheet. However, polyvinylchloride contains some problems, for example a harmful gas shall be produced when incinerated. Thus, polypropylene (PP) has been employed as a material free from the above problems and having a good moistureproofness instead of polyvinylchloride. In order to achieve high moistureproofness of the resin sheet, a use of a composite material of polypropylene and, e.g., polyvinylidenechloride (PVDC) or polychlorotrifluoroethylene (PCTFE) has been proposed.
The present applicant proposed a polypropylene molding machine providing properties of the resin sheet better than the properties of moldability, molding speed, sealability, curability and half-cuttability of the resin sheet provided by a conventional polyvinylchloride molding machine (See Japanese patent application SHO. 63-231578, which corresponds to U.S. application Ser. No. 07/406,727, filed Sep. 13, 1989). However, when the resin sheet has a multilayered or laminated structure made of a plurality materials instead of a single-layered structure, the laminated resin sheet must be thermally molded at a low temperature since each material of the laminated resin sheet has a different melting point and softening point. Therefore, a conventional high-temperature vacuum molding machine and process for a single-layered resin sheet has failed to attain satisfactory properties such as moldability to a laminated resin sheet.
A prior-art hot plate heating and plug assist compressed air molding machine has been provided as a molding machine which can also mold a laminated resin sheet. This prior-art molding machine can mold a PVC single-layered sheet and PVC/PCD laminated sheet, however, provides poor high-speed moldabilities thereto and a poor moldability to PP. In addition, this prior-art molding machine entails a problem in that it fails to provide a good moldability to a thin resin sheet other than the above problems. In addition, indirect heating and drum vacuum molding machines (See Japanese examined utility model application publications SHO. 60-7131 and SHO. 56-39266, Japanese unexamined patent application publications SHO. 58-126117 and SHO. 58-1261 and the above-referenced Japanese patent application SHO. 63-231578) can mold the PP single-layered sheet and PCV/PVDC laminated sheet but difficultly mold laminated sheets such as a PP/PCTFE/PP laminated sheet and PVC/PCTFE/PP laminated sheet.
An object of the present invention is to provide a process of molding a thermoplastic sheet having a fine molding performance regardless of a sheet structure and material.
SUMMARY OF THE INVENTION
A process of molding a thermoplastic sheet according to the present invention, the process having the step of feeding the thermoplastic sheet to a molding drum in order to thermally mold a pocket on the thermoplastic sheet, is characterized in that the process comprises the steps of: bringing a thermoplastic sheet into close contact with the outer cylindrical surface of a molding drum, the molding drum having plural cavities whose each edge surface has a heat insulation layer, externally heating the thermoplastic sheet and concurrently vacuum sucking the thermoplastic sheet through the cavities of the molding drum; and a full-molding step which includes vacuum sucking through the cavities of the molding drum the thermoplastic sheet with the pocket premolded therein into the cavity and concurrently full-molding the pocket by means of a plug. A failure of essentially the same vacuum suction through the cavity in the full-molding step as that in the premolding step provides a poor mold-releasability of the sheet from the plug which results in poor molding conditions.
The full-molding step of the present molding process may also be adapted for another step in which the molding drum is continuously rotated and a rotatable roll plug is inserted into the cavity provided on the surface of the molding drum in order to full-mold the pocket on the thermoplastic sheet in the cavity.
In accordance with the process for thermally molding the thermoplastic sheet by means of the roll plug, a molding speed is preferably 10 m/min or less and an optimum temperature of the roll plug is 40 degrees Celsius to 130 degrees Celsius. The top surface of the roll plug is preferably slightly tapered toward its rotational direction of the roll plug.
In the full-molding step, the molding drum may be intermittently rotated and while the molding drum stays, a linearly reciprocating plug may be inserted into the cavity of the molding drum so that the thermoplastic sheet is full-molded. In this embodiment, an optimum temperature of the reciprocating plug is 20 degrees Celsius to 50 degrees Celsius.
The linearly reciprocating plug is preferably so controlled that a speed of the plug entering the cavity is 5 cm/sec or more, a stay time at bottom dead center of the plug, namely, the location of the deepest penetration of the plug into the mold cavity, is 0.2 second or more.
The thermoplastic sheet is preferably fed into the molding drum under a tension of 0.2 kg/cm to 2.4 kg/cm and sucked thereonto by a vacuum suction through a suction through-hole defined on the molding drum so as to be in close contact with the outer cylindrical surface of the molding drum. The above tension may be produced by an arrangement comprising a brake roller or dancer roller.
The temperature of the molding drum preferably maintains 30 degrees Celsius to 80 degrees Celsius.
In accordance with the present molding process, the vacuum degree through the premolding step is preferably more than 400 mm Hg and that of the full-molding step is preferably more than 600 mm Hg.
The clearance between the roll plug or linearly reciprocating plug and the cavity in the longitudinal direction is settled from (the thickness of the thermoplastic sheet) to (the total of the thickness of the thermoplastic sheet plus 250 μm), preferably at (the total of the thickness of the thermoplastic sheet plus 150 μm), when the roll plug stays at its bottom dead center.
The present invention is applicable to a thermoplastic sheet comprising at least a layer of polypropylene. This thermoplastic sheet may also comprise a relatively thin sheet in the form of film.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram of a blister molding machine used in a first Embodiment of the present invention;
FIG. 2 is a front view of the main part of the blister molding machine of FIG. 1;
FIG. 3 is a perspective view of a molding drum;
FIG. 4 is a fragmentary section through a cavity defining portion of the molding drum of FIG. 3;
FIG. 5 is a main fragmentary section through a plug;
FIG. 6 is a front view of the main part of a blister molding machine used in a second Embodiment of the present invention; and
FIG. 7 illustrates fragmentary section of a plug and a portion of a molding drum of the second Embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The preferred embodiments of the processes for molding a thermoplastic sheet in the present invention and a used blister packager will be described together with reference to the drawings hereinafter.
Embodiment 1
As shown in FIG. 1, a blister packager used in Embodiment 1 comprises a molded sheet feeder 10, a tensioner 20, a pocket former 30, a content charger 40, a sealer 50 and a trimmer 60 arranged in this order.
The molded sheet feeder 10 comprises a sheet feed roller 12 onto which a thermoplastic sheet 11 is wound and a guide roller 13.
The tensioner 20 comprises a first guide roller 21, a brake roller 22 and a second guide roller 23. The first guide roller 21 is positioned on the side of the guide roller 23 so that the thermoplastic sheet 11 is wound on to the outer cylindrical surface to the brake roller 22 in order to provide a greater contact area between the thermoplastic sheet 11 and the brake roller 22. The brake roller 22 may comprise, e.g., a roller with a power brake. The brake roller 22 applies a tension to a part of thermoplastic sheet 11 in a pulled position caused by the rotating molding drum 31.
As best shown in FIG. 2, the pocket former 30 comprises a rotatable molding drum 31, a rotatable roll plug 32 disposed upper side of this molding drum 31 so that the outer cylindrical surface of the roll plug 32 and molding drum 31 are in contact with each other, and a semicircular cylindrical infrared heater 33 opposite to and covering essentially a half area of the outer cylindrical surface of the molding drum 31.
As shown in FIGS. 2 and 3, the outer cylindrical surface of the molding drum 31 defines therein a plurality of cavities 34 for forming pockets 1 and spaced at predetermined pitches and a plurality of suction holes 35 through which the thermoplastic sheet 11 is vacuum sucked to the outer cylindrical surface of the molding drum 31 and which are spaced at predetermined pitches. As best shown in the FIG. 4 section, each of the cavities 34 contains a heat insulation layer 36 made, e.g., of polyamide and fitting the overall side edge surface 34B of the cavity 34. The wall thickness of the heat insulation layer 36 is, e.g., 1 mm. Each cavity 34 is selected to have dimensions corresponding to those of the pocket 1 containing, e.g., a third-sized medicine capsule therein. Each suction hole 35 is positioned in a portion of the outer cylindrical surface of the molding drum 31 which does not have the cavity 34. The suction holes 35 is formed into the plus-shape and the minus-shape. The interior of the molding drum 31 has a plurality of vacuum communication holes 37 communicating with a plurality of small holes 34A defined at the bottom of each cavity 34 and has a plurality of vacuum communication holes 38 communicating with a plurality of the suction holes 35. The vacuum communication holes 37 and 38 are communicating with a vacuum producing means (not shown). The cavities 34 aligned in a direction perpendicular to the rotational direction of the molding drum 31 (in a direction parallel to the axle of the molding drum 31), are controllable in respect of the degree of the vacuum. In the full-molding step, thus aligned cavities 34 into which plugs 39 of a roll plug 32 are inserted are vacuum sucked at the vacuum degree equal to or greater than those of other cavities 34. The maximum magnitude of the vacuum sucked in each cavity is insufficient to pull the thermoplastic sheet out of engagement with the plug. As a result, the thermoplastic sheet will conform to the shape of the plug and not to the shape of the cavity.
As shown in FIG. 2, the roll plug 32 has a cylindrical shape on which has a plurality of plugs 39 each having a shape corresponding to that of each cavity 34 in the molding drum 31, the plugs 39 being arranged axially of and in the rotational direction of the roll plug 32 at the same pitches as those of the cavities 34 of the molding drum 31. As shown in FIG. 5, the top surface 39A of each of the plugs 39 is slightly tapered toward the rotational direction of the roll plug 32. For example, the height of the leading edge 39B of each plug 39 for third-sized capsule from the outer cylindrical surface of the roll plug 32 is slightly, e.g., 0.5 mm lower than that of the trailing edge 39C of the plug 39 for third-sized capsule. The bottom wall of the pocket formed in the thermoplastic sheet will end up being of a shape different than the end of the plug 39. since the molding temperature is rather low (see examples below), the thermoplastic sheet will elastically recover so that the desired cavity bottom wall configuration will be achieved. The above-described shape of the plug 39 can be provided with a flat top surface of a molded pocket 1. The plug 39 comprises a plug body of Al the surface of which is coated with Teflon (registered trademark), a kind of fluorocarbon resin. Alternatively, the plug 39 may comprise a single plug body of Al. The roll plug 32 has an inner heater (not shown) therein. The outer diameter of the roll plug 32 is optional.
As shown in FIG. 1, the content charger 40 comprises a half-slitter 41 cutting perforations into the stream direction of the thermoplastic sheet 11, a content feeder 42 feeding a content, e.g., a medicine capsule into the pocket 1.
The sealer 50 comprises a seal feed roller 52 on which a roll of mount 51, e.g., Al foil is wound, two guide rollers 53 and 54, two sealing rollers 55 and 56 heat sealing the pockets 1 in the thermoplastic sheet 11, and a seal receiving roller 57.
The trimmer 60 comprises a curl eliminator 61, two guide rollers 62 and 63, a transverse half-slitter 64 cutting perforations into and transversely of the thermoplastic sheet 11, three guide rollers 65, 66 and 67, and a punching machine 68 punching in the form of blister package the thermoplastic sheet 11 to which the mount 51 has been heat sealed.
When the plug 39 is inserted as deep as it can go into corresponding cavity 34 as shown in FIG. 2, namely, at the location of the bottom dead center of the plug, and just before being withdrawn therefrom, a clearance is provided between the leading edge 39B (FIG. 5) of the plug 39 and the corresponding leading edge surface 34B of the cavity 34. A further clearance is provided between the trailing edge 39C of the plug 39 and the corresponding trailing edge surface 34C of the cavity 34, which clearances are in the range of the thickness of the thermoplastic sheet to the thickness of the thermoplastic sheet 11 plus 250 μm, preferably a thickness of the thermoplastic sheet 11 plus 150 μm. A clearance C exceeding this total increases an inclination of the side wall of the pocket 1 and thereby the pocket 1 fails to well reproduce the shape of the plug 32.
Hereinafter, the blister packaging process including a subprocess of molding the pocket 1 of the thermoplastic sheet 11 by means of the blister packager of the above-described arrangement.
As shown in FIG. 1, the sheet feed roller 12 of the molded sheet feeder 10 feeds the thermoplastic sheet 11 which is delivered to the brake roller 22 of the tensioner 20 through the guide rollers 13 and 21 and further to the molding drum 31 through the guide roller 23. During this traveling of the thermoplastic sheet 11, the brake roller 22 applies a braking force to the thermoplastic sheet 11 opposite to a pull of the rotating molding drum 31 to produce a predetermined tension in the thermoplastic sheet 11. The tension is preferably within 0.2 kg/cm to 2.4 kg/cm. Thus, when the thermoplastic sheet 11 has, e.g., a 215-mm width, the thermoplastic sheet 11 will receive an about 5 kg/215 mm to 50 kg/215 mm tension. The tensions which are smaller than 0.2 kg/cm and on the other hand, greater than 2.4 kg/cm cause crinkles in areas of the thermoplastic sheet 11 between adjacent PTP moldings and between adjacent pockets 11.
As shown in FIG. 2, the pocket former 30 premolds the pockets 11 in the thermoplastic sheet 11 which has been fed to the molding drum 31. The infrared heater 33 heats the molding drum 31 of the pocket former 30 at 30 degrees Celsius to 80 degrees Celsius, preferably, 50 degrees Celsius to 60 degrees Celsius. Even when the heating temperature of the infrared heater 33 is below 30 degrees Celsius or above 80 degrees Celsius, a shrinking in a molding unpreferably increases. The thermoplastic sheet 11 under the tension is vacuum sucked through the suction holes 35 defined in the molding drum 31 to be in close contact with the outer cylindrical surface of the molding drum 31 so that corresponding portions of the thermoplastic sheet 11 in contact with the cavities 34 are vacuum sucked into the cavities 34 through the vacuum communication holes 37. The vacuum of the cavities 34 in the premolding position is preferably no less than 400 mm Hg up to 760 mm Hg. Herein, the vacuum is defined as a value representing a degree of rarefaction below normal atmospheric pressure. Vacuum sucking the thermoplastic sheet 11 through only the cavities 34 but not the suction holes 35 undesirably increases the occurrence of crinkle between adjacent pockets and adjacent PTP moldings. The pocket blank 1 produced in the premolding step is not a full molding exactly fitting the cavity 34 but a premolding with a 50% or less depth of the full molding. Appropriate adjustments of the temperature of the infrared heater 33, the molding speed and the vacuum can control the molding degree of the pocket blank 1.
Then, as shown in FIG. 2, the molding drum 31 rotates to move the thermoplastic sheet 11 which includes the molded pocket blanks 1 to the roll plug 32 full-molding the pockets 1. At this time, the heater (not shown) contained in the roll plug 32 has heated the roll plug 32 at a predetermined temperature. The heating temperature of the roll plug 32 is preferably 40 degrees Celsius to 130 degrees Celsius. When it is below 40 degrees Celsius or above 130 degrees Celsius, the shape of a molding is defective and the mold-releasability of a molding is defective. The thermoplastic sheet 11 has been vacuum sucked to the molding drum 31 under a vacuum of no less than 600 mm Hg immediately before an axial row of plugs 39 is inserted into an axial row of pocket blanks 1 of the thermoplastic sheet 11. The vacuum of the full-molding step is selected equal to or greater than that of the premolding step. The plugs 39 of the roll plug 32 in a rotating position are inserted into the pocket blanks 1 vacuum sucked into the cavities 34 to full mold the pockets 1. The maximum magnitude of the vacuum sucked in each cavity is insufficient to pull the thermoplastic sheet out of engagement with the plug. As a result, the thermoplastic sheet will conform to the shape of the plug and not to the shape of the cavity.
Then, as shown in FIG. 1, the thermoplastic sheet 11 which has the full-molded pockets 1 is delivered to the content charger 40. The axial half-slitter 41 of the content charger 40 cuts perforations into and axially of the thermoplastic sheet 11. The content feeder of the content charger 40 feeds a content into the pockets 1.
Then, the thermoplastic sheet 11 with the pockets 1 charged with the content is delivered to the sealer 50. The seal feed roller 52 feeds the A1 foil constituting the mount 51 to bites between the sealing rollers 55 and 56 and the seal receiving roller 57. The sealing rollers 55 and 56 and the seal receiving roller 57 together heat seal the mount 51 to the thermoplastic sheet 11.
Then, the sealed thermoplastic sheet 11 and mount 51 are together delivered to the trimmer 60. The curl eliminator 61 eliminates a curl of an assembly of the thermoplastic sheet 11 and mount 51. The transverse half-slitter 64 cuts perforations into and transversely of the assembly of the thermoplastic sheet 11 and mount 51. The punching machine 68 punches package units to provide blister packages.
Experiments 1-4
The blister packager and packaging process of Embodiment 1 produced PTP blister moldings with process conditions specified as below. Thermoplastic sheet: Three kinds thereof having different materials and thicknesses were employed.
Material and Thickness
(1) High-transparent nonoriented polypropylene sheet (IDEMITSU PURELAY MG-100 (trademark)), 0.2-mm thickness;
(2) PP/PCTFE/PP laminated sheet, 0.32-mm thickness; and
(3) PVDC/PCTFE/PP laminated sheet, 0.32-mm thickness.
Molding drum
Heat insulation layer attached to the side edge surface of each cavity: made of polyamide.
Molding drum temperature: 60 degrees Celsius
Cavity size: third-sized capsule size
Molding speed: 10 m/min
Plug
Material: Teflon coated A1 plug
Tapering in top surface of plug: Height of leading edge is 0.5 mm lower than that of trailing edge with reference to line passing past leading edge apex and parallel to tangent passing past tangent point at center between leading and trailing edges.
Plug temperature: 45 degrees Celsius
Clearance between plug and cavity: 0.25 mm
Premolding
Pocket blank was molded at about 2-mm depth of cavity at the center of an axial edge of the cavity.
Full-molding
Interiors of cavities were vacuum sucked for full-molding immediately before plugs are inserted into the cavities.
The transparency of each of the three kinds of thermoplastic sheet used for a blister package in the form of third-sized capsule and produced by the present Experiments was good. The thickness of the top wall of the pocket 1 was no less than 70% thickness of the thermoplastic sheet 1 and a wall thickness distribution in a full-molding was good. Thus, even a thinned thermoplastic sheet provided a good molding. Since even a 10 m/min molding speed provided a good molding, a high-speed molding can be conducted. Since the temperature of the molding drum was 60 degrees Celsius and that of the plug was 45 degrees Celsius so that a low temperature molding of the thermoplastic sheet was conducted, the present blister molding process saved heating energy. In addition, three kinds of thermoplastic sheet 11 with different materials and thicknesses were molded to produce pockets and the wall thickness etc. of a molding made of each thermoplastic sheet 11 entailed no problem, so that the present molding process is applicable to all sorts of thermoplastic sheet 11.
Table 1 shows results of measurements of the top wall thickness of each of the pockets of Experiments 1-4 which were molded under the conditions from the high-transparent nonoriented polypropylene sheet (0.2l -mm thick) as the thermoplastic sheet, and results of ratings of the transparency and mold-reproducibility of the pockets. Table 1 also shows corresponding results of Controlling Examples 1-3. In Table 1, legends ∘ in the column of rating represent goodness and legends x in the column of mold-reproducibility represent that the thermoplastic sheet failed to produce molded pockets. A tension applied to each of the thermoplastic sheets was 1.0 kg/cm.
TABLE 1__________________________________________________________________________ External heating Heat sheet Drum Plug Rating insulation temperature temperature temperature Vacuum (mmHg) Top wall Sheet layer (°C.) (°C.) (°C.) (1) (2) (μm) (3) (4)__________________________________________________________________________Experiments1 PP Polyimide 120 60 45 500 750 160˜170 ◯ ◯2 PP Polyimide 120 30 45 500 750 150˜160 ◯ ◯3 PP Polyimide 120 60 80 500 750 150˜160 ◯ ◯4 PP Polyimide 120 60 130 500 750 140˜150 ◯ ◯ControllingExamples1 PP None 120 60 45 500 750 -- ◯ X2 PP Polyimide 120 60 None 500 750 -- ◯ X3 PP Polyimide 120 60 45 -- 750 20˜25 ◯ ◯__________________________________________________________________________ (1): Premolding (2): Fullmolding (3): Transparency (4): Moldreproducibility Embodiment 2
A packager used in the present Embodiment 2 comprises essentially the same molded sheet feeder 10, a tensioner 20, a pocket former 30, a content charger 40, a sealer 50 and a trimmer 60 as Embodiment 1. However, the arrangements of the tensioner 20 and pocket former 30 of Embodiment 2 slightly differs from those of the tensioner 20 and pocket former 30 of Embodiment 1.
That is, as shown is FIG. 6, the tensioner 20 comprises a first guide roller 21, brake roller 22, dancer roller 27 floated on a part of a thermoplastic sheet 11 running between two rollers 25 and 26, intermediate roller 28, and second guide roller 23. Controlling the weight of the dancer roller 27 applies a predetermined tension to a running part of the thermoplastic sheet 11 intermittently delivered to the pocket former 30. While the molded sheet feeder 10 continuously feeds the thermoplastic sheet 11, the pocket former 30 intermittently receives the thermoplastic sheet 11, which will cause a sag in the thermoplastic sheet 11. However, the dancer roller 27 eliminates the sag so as to stably apply the predetermined tension to the running part of the thermoplastic sheet 11 intermittently delivered to the pocket former 30.
As shown in FIG. 6, the pocket former 30 comprises an intermittently driven and rotatable molding drum 31, linearly reciprocating plug 71 provided above the molding drum 31, and semicylindrical infrared heater 33 opposite to and near the outer cylindrical surface of the molding drum 31 and movable to and away from the molding drum 31. The plugs 71 are supported on a plug support 72. A drive means 73 comprising a combination of a motor and eccentric cam or a reciprocating hydraulic cylinder moves the plugs 71 to and away from the cavity 34 of the molding drum 31. Each of the plugs 71 comprise a plug body made of A1 with the surface coated with an oxide film or Teflon (trademark). The plugs 71 are arranged in the form of two rows spaced in the rotational direction of the molding drum 31. The plug support 72 contains a heater (not shown). As shown in FIG. 7, a clearance C; between the front bottom edge of the linearly reciprocating plug 71 and the leading edge surface of the cavity 34 and a clearance C; between the rear bottom edge of linearly reciprocating plug 71 and the trailing edge surface of the cavity 34 are selected from (the thickness of the thermoplastic sheet 11) to (the total of the thickness of the thermoplastic sheet 11 plus 250 μm), preferably at (the total of the thickness of the thermoplastic sheet 11 plus 150 μm), when the linearly reciprocating plug 71 stays at its bottom dead center (FIG. 7 does not show the position of the linearly reciprocating plug 71 staying at its bottom dead center). A clearance C exceeding this total increases an inclination of the side wall of the pocket 1 and thereby the pocket 1 fails to well reproduce the shape of the plug 71. A dancer roller 46 is floated on a part of the thermoplastic sheet 11 running between two rollers 44 and 45 between the molding drum 31 and the content feeder 42 in order to apply a predetermined tension through a guide roller 43 to the part of the thermoplastic sheet 11 running between the two rollers 44 and 45.
A blister packaging process with the blister packager of Embodiment 2 used will be described hereinafter. Embodiment 2 also molds the pockets 1 through essentially the same steps as in Embodiment 1.
That is, as shown in FIG. 1, the thermoplastic sheet 11 is fed by the sheet feed roller 12, delivered to the brake roller 22 and dancer roller 27 of the tensioner 20 and further through the guide rollers 28 and 23 to the molding drum 31 as the molding drum 31 is intermittently driven. The weight of the dancer roller 27 causes a 0.2 kg/cm to 2.4 kg/cm tension in the thermoplastic sheet 11.
Then, as shown in the FIG. 2 illustration of the arrangement of the molding drum 31 and FIG. 6, the thermoplastic sheet 11 is fed to the pocket former 30 of the molding drum 31 in order to be premolded. The infrared heater 33 has heated the molding drum 31 at 30 degrees Celsius to 80 degrees Celsius. The thermoplastic sheet 11 under the tension is vacuum sucked through the suction holes 35 defined in the molding drum 31 to be in close contact with the outer cylindrical surface of the molding drum 31 so that corresponding portions of the thermoplastic sheet 11 in contact with the cavities 34 are vacuum sucked into the cavities 34 through the vacuum communication holes 37. The vacuum of the cavities 34 in the premolding position is preferably no less than 400 mm Hg up to 760 mm Hg. Thus, pocket blanks 1 each with a 50% or less depth of the full-molded pocket 1 are molded.
Then, as shown in FIG. 6, the intermittent rotation of the molding drum 31 delivers the thermoplastic sheet 11 with the pocket blanks 1 to under the linearly reciprocating plugs 71. The plugs 71 descend to the molding drum 31 when the molding drum 31 is in a staying position so as to be inserted into the pocket blanks 1 placed in the cavities 34 to full mold the pockets 1. In the full molding step, the thermoplastic sheet 11 has been vacuum sucked under a 600-mm Hg vacuum or more immediately before the plugs 71 are inserted into the pockets 1. An entering speed of the plugs 71 is preferably selected 5 cm/second or more. When the entering speed is below 5 cm/second, the thickness of the top wall of each full-molded pocket 1 is excessively increased. The stay time of the plugs 71 is preferably 0.2 second or more. A below 0.2 second stay time of the plugs 71 deteriorates the mold-reproducibility of the pockets 1. A heating temperature of the plugs 71 is preferably selected 20 degrees Celsius to 50 degrees Celsius. A below 20 degrees Celsius heating temperature of the plugs 71 excessively increases the thickness of the top wall of each pocket 1 and on the other hand an above 50 degrees Celsius heating temperature thereof unpreferably deteriorates the mold-releasability of each molding.
Then, as in Embodiment 1 of FIG. 1, the thermoplastic sheet 11 with the pockets 1 full-molded is delivered to the content charger 40, sealer 50 and trimmer 60 in this order to produce blister packages of Embodiment 2.
Experiments 5-13
The blister packager and packaging process of Embodiment 2 produced PTP blister moldings with process conditions specified as below:
Thermoplastic sheet: Three kinds thereof having different materials and thicknesses were employed.
Material and Thickness
(1) High-transparent nonoriented polypropylene sheet (IDEMITSU PURELAY MG-100 (trademark)), 0.15-mm thickness; and
(2) the same, 0.2-mm thickness.
Molding drum
Heat insulation layer attached to the side edge surface of each cavity: made of polyamide.
Molding drum temperature: 30 degrees Celsius, 70 degrees Celsius
Molding cycle: 100 shots/min
Plug
Material: Oxide film coated plug made of A1
Plug shape: Third-sized capsule shape
Plug temperature: 30 degrees Celsius, 80 degrees Celsius
Clearance C between plug and cavity: 300 μm, 400 μm
Plug entering speed: 3.3 m/seconds, 8.6 m/seconds
Stay time at bottom dead center: 0.25 second, 0.14 second
Premolding
Pocket blank was molded at about 2-mm depth of cavity at a center of an axial edge of the cavity.
Full-molding
Interiors of cavities were vacuum sucked for full-molding immediately before plugs are inserted tightly into the cavities.
The mold-releasability from plug and plug mold-reproducibility of full-molded pockets of each of Experiments 5-13 were rated and the top wall thickness and side wall thickness of molded pocket were measured. Table 2 shows results of the rating and measurements. Table 2 also shows corresponding results of Controlling Example 4. In Table 2, the legends ∘, Δ and × in the column of mold-releasability from plug respectively represent that the mold-releasability from plug is good, that a pocket is released from a plug but slightly sticks on the plug and that a full-molded pocket is 10% or more shrunk. A tension applied to each of the thermoplastic sheets was 1.0 kg/cm.
TABLE 2__________________________________________________________________________ Molding drum Cavity Plug heat Plug Cavity Entering Molding (pocket)(1) (2) insulation clearance C vacuum (3) speed (4) (7) (μm)(μm) (°C.) layer (μm) suction Material (°C.) (cm/sec) (sec) (5) (6) (8) (9)__________________________________________________________________________Experi-ments5 200 30 Present 300 Present Al, Oxide film 30 8.6 0.25 ◯ ◯ 160 806 150 30 Present 300 Present Al, Oxide film 30 8.6 0.25 ◯ ◯ 120 707 150 70 Present 300 Present Al, Oxide film 30 8.6 0.25 ◯ Δ 130 808 150 30 Present 400 Present Al, Oxide film 30 8.6 0.25 ◯ Δ 120 639 150 30 Present 300 None Al, Oxide film 30 8.6 0.25 Δ Δ 120 7010 150 30 Present 300 Present Al, Teflon coating 30 8.6 0.25 ◯ Δ 120 7011 150 30 Present 300 Present Al, Oxide film 80 8.6 0.25 Δ Δ 135 7012 150 30 Present 300 Present Al, Oxide film 30 3.3 0.25 ◯ ◯ 140 3213 150 30 Present 300 Present Al, Oxide film 30 8.6 0.14 ◯ Δ 140 30(10) 150 30 None 300 Present Al, Oxide film 30 8.6 0.25 ◯ X -- --__________________________________________________________________________ (1): Sheet thickness (2): Temperature (3): Temperature (4): Stay time at bottom dead center (5): Moldreleasability from plug (6): Moldreproducibility (7): Wall thickness (8): Top wall thickness (9): Side wall thickness (10): Controlling Example
As understood from Table 2, Embodiment 2 produced good moldings even when temperatures of the molding drum 31 and plug 71 are 30 degrees Celsius, so that a low-temperature molding of the pockets can be conducted and thereby heating energy can be saved. Since the mold-releasability and mold-reproducibility from plug 71 of the molding are improved by means of adjusting conditions other than the entering speed of plug 71 even when the entering speed of the plug 71 is as high-speed as 8.6 m/seconds, a high-speed molding can be conducted. In particular, since the top wall thickness of the pocket insufficiently increased so that a wall thickness distribution of the molding, even a wall-thinned thermoplastic sheet 11 provides a good molding.
In accordance with Embodiment 1, the tensioner 20 includes a brake roller 22 applying a tension to the thermoplastic sheet 11. Alternatively, the tensioner may include another arrangement. As the present applicant has proposed in Japanese patent application SHO. 63-231578 for example, the tensioner may include an arrangement in which a braking rod brakes a ring fastened to the outer cylindrical surface of a rubber roller.
In addition, the vacuum of each axial row of cavities 34 is adjustable, so that in accordance with Embodiments 1 and 2, the interiors of the cavities 34 into which the plugs 39 and 71 are inserted in the full-molding step are vacuum sucked under a vacuum higher than that of the remaining cavities 34. On the other hand, the vacuum of the cavities 34 into which the plugs 39 and 71 are inserted may equal that of the remaining cavities 34 closed by the thermoplastic sheet 11 as described above, so that a need for a vacuum controller controlling each axial row of cavities 34 is eliminated.
The control of the vacuum of each axial row of cavities 34 is preferable in order to improve the molding performance of the plug former 30.
In accordance with Embodiments 1 and 2, the respective roll plug 32 and plug support 72 contain heaters for heating the plugs 39 and 71. However, the roll plug 32 and linearly reciprocating plugs 71 each have an infrared heater provided outside and near them.
In accordance with Embodiments 1 and 2, the heat insulating layer 36 attached to the side edge of the cavity 34 is made of polyamide. However, the heat insulating layer 36 may be made of another material.
The Embodiments 1 and 2 include the blister packaging step. However, the present invention may include only steps up to the step of full-molding a pocket in a thermoplastic sheet.
A process of molding a thermoplastic sheet of the present invention can well thermally mold a pocket in the thermoplastic sheet regardless of the material and structure of the thermoplastic sheet.
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A process of molding a thermoplastic sheet for making blister packaging. The process particularly includes premolding steps of brining the sheet into close contact with the outer cylindrical surface of a molding drum, preheating the sheet and concurrently vacuum sucking the sheet into a cavity defined on the outer cylindrical surface of the drum, to partially form a pocket in the sheet, and a full-molding step of vacuum sucking the sheet and concurrently inserting the sheet into the cavity by means of a plug so that the pocket is conformed to the shape of the plug.
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SUMMARY OF THE INVENTION
1. Field of Invention
This invention relates to a protective wear, and more particularly, to a protective hood with an adjustable visor.
2. Summary of Invention
The present invention is a flexible hood provided with a visor movable from a distal position to a proximate position relative to the ocular area of a wearer of the hood and a slack fold coincident to a bottom portion of the visor providing the visor with a range of movement defined by the distal and proximate positions. As the visor is moved towards the ocular area of the wearer (the person's eyes), the peripheral vision afforded by the visor increases. By moving the visor in close proximity to the wearer's eyes, the size requirements of the visor may be reduced while still providing acceptable outward vision. Furthermore, by making the visor adjustable, outward vision can be optimized for a wide range of facial profiles including persons wearing eyeglasses. A restraint means is provided to align the vertical position of the vision with the ocular area of the wearer when the visor is in the proximate position. Without the restrain means, the slack fold would permit the visor to move towards the wearer's forehead and thus not be vertically aligned with the ocular area for proper outward vision.
An alterative embodiment to the invention may replace the slack fold with bellows, either interfaced into the hood or integral in a dip molded, all-rubber hood. The slack and the bellows form substantially the same function to provide the visor with travel towards the ocular area of the wearer.
In one embodiment of the invention, at least one substantially horizontal elongate member having a lengthwise axis in transverse, underlying relation to the visor is provided. A guide member having a first end and a second end is also provided. The first end of the guide member is secured to the visor and the second end is slideably received by the elongate member whereby movement of the visor to and from the distal and proximate positions is linearly restrained by the lengthwise axis of the at least one substantially horizontal elongate member. Preferably, the at least one substantially horizontal elongate member is downwardly angled from a horizontal plane whereby the visor is positioned lower relative to the ocular area when in the proximate position and the visor is positioned higher relative to the ocular area when in the distal position. The downward angle provides a correction for vertical outward visibility.
A locking means may be provided to secure the guide member at a location in the at least one elongate member representative of the proximate position of the visor. In one embodiment, at least one notch integral to the guide member is provided. The at least one notch is positioned in transverse relation to the lengthwise axis and is adapted to secure the guide member at a location in the at least one elongate member representative of the proximate position of the visor. A plurality of notches may be employed similar to serrations wherein multiple visor proximity positions may be easily selected. In another embodiment of the invention, the locking means may include a hook and loop interface to secure the guide member at a location in the at least one elongate member representative of the proximate position of the visor. In still another embodiment of the invention a snap button secures the guide member at a location in the at least one elongate member representative of the proximate position of the visor. In yet another embodiment of the invention the guide member is formed of an elastomeric material forming a resilient, interference fit with the at least one elongate member. When negative pressure exists in the hood, the visor may be drawn toward the wearer's face. By utilizing the locking means, the visor is restrained from unwanted movement.
Protective hoods, particularly those that are packaged with a respiratory filter are often constructed with flexible visors made of PVC, polycarbonate, polyester, urethane or the like. Selection of the appropriate visor material is often dependent on costs, heat resistance, anti-fog qualities, transparency, chemical resistances, storage life and the like. Virtually all suitable flexible visor materials will crease if stored in a folded configuration, particular when stored at high temperatures. Creases in the visor distort outward visor and are therefore undesirable. One advantage of the present invention is its ability to compactly fold with a filter without creasing the visor.
Respiratory filters are typically positioned in front of the wearer's mouth and thus, disposed underneath the visor of the hood. When packaging the respiratory hood for storage it is desirable to make the overall size of the unit as compact as possible. As described above, it is also desirable to avoid folding the visor whereby creases may form and inhibit outward visibility. If the visor is configured in the hood in close proximity to the ocular area of the wearer, good peripheral vision is achieved. However, the visor cannot lay flat over the substantially rigid filters and creases form in the visor. Alternatively, the visor may be positioned away from the ocular area so that it folds without creases onto the filters during storage. However, the visor is now positioned away from the eyes of the wearer resulting in poor peripheral vision.
The aforementioned problems are overcome by providing at least one filter coupled to the hood and disposed below the visor, the at least one filter having at least one substantially planer surface while the apparatus is in a packaged state. A fold line in the hood is coincident and parallel to the lower portion of the visor wherein the fold line abuts an edge of the substantially planer surface while the visor is in the distal position, the visor lying flat against the substantially planer surface while the apparatus is in a packaged state. The at least one substantially planer surface may be integral to the at least one filter or detachable from the at least one filter when the apparatus is in an unpackaged state. The planer surface also permits the visor to be constructed of a substantially rigid material such as glass or acrylic with superior optical properties for outward vision.
BRIEF DESCRIPTION OF DRAWINGS
For a fuller understanding of the nature and objects of the invention, reference should be made to the following detailed description, taken in connection with the accompanying drawings, in which:
FIG. 1 is a side elevation view of a prior art hood having a visor in relative close proximity to the ocular area of the wearer.
FIG. 2 is a side elevation view of a prior art hood having a visor in relative distant proximity to the ocular area of the wearer.
FIG. 3 is a side elevation view of an embodiment of the invention wherein the visor is in a distal position relative to the ocular area of the wearer.
FIG. 4 is a side elevation view of an embodiment of the invention wherein the visor is in a proximate position relative to the ocular area of the wearer.
FIG. 5 is a front elevation view of an embodiment of the invention.
FIG. 6 is a side elevation detail view of an embodiment of the invention.
FIG. 7 is a front elevation view of an embodiment of the invention having a substantially planer surface for receiving the visor in flat juxtaposition.
FIG. 8 a side elevation detail view of an embodiment of the invention.
FIG. 9 is a side elevation view of an embodiment of the invention in a packaged state.
FIG. 10 is a side elevation detail view of an embodiment of the invention utilizing a resilient tension spring to vertically restrain the position of the visor relative to the ocular area of the wearer.
FIG. 11 is a front elevation, partially exploded view of an alternative embodiment of the invention.
DETAILED DESCRIPTION
Referring to prior art FIGS. 1 and 2, flexible hood 10 is provided with visor 20 . Filter 30 is disposed below visor 20 . The hood illustrated is neck sealable 40 in this exemplary embodiment. The origin of vision for the wearer is noted as vision epicenter 50 . The distance between the visor 20 and vision epicenter 50 in FIG. 1 is represented by d 1 and in FIG. 2 by d 2 . Peripheral vision angle α 1 of FIG. 1 is greater than peripheral vision angle α 2 of FIG. 2 . The greater angle affords the wearer superior peripheral vision. Accordingly, it can be seen that moving the visor closer to the eyes of the wearer (the ocular area) is desirable to enhance outward visibility. Furthermore in most instances, the preferred location of the visor while the hood is being worn is the position directly above the breathing interface inside the hood.
FIGS. 3 and 4 depict a preferred embodiment of the invention. Rod 60 is secured to filter 30 by forward support leg 60 a and rearward support leg 60 b. Accordingly, rod 60 is vertically spaced apart from filter 30 . It should also be observed that rod 60 has a longitudinal axis of symmetry that is disposed substantially perpendicular to the plane of visor 20 . As depicted in FIGS. 3 and 4, the plane of the visor is perpendicular to the plane of the visor. Thus, as drawn, rod 60 is in the plane of the paper. Guide member 70 has first end 71 secured to visor 20 and second end 72 is apertured to slideably receive rod 60 . In a preferred embodiment of the invention, second end 72 and rod 60 are slideably coupled to one another by a mechanical interference fit that permits an infinite number of positions of functional adjustment. It is also preferred that an adjustment tab, not depicted, be integrated to guide member 70 wherein the user can easily grip and adjust guide member 70 . It is also anticipated that first end 71 may be alternatively secured to hood 10 in close proximity to visor 20 to achieve substantially the same mechanical effect. Movement of guide member 70 and hence of visor 20 from the distal or extended position of FIG. 3 to the proximate or retracted position of FIG. 4 is accomplished by sliding guide member 70 along the length of rod 60 in a left-to-right direction as drawn. Movement of guide member 70 and hence of visor 20 from the retracted position of FIG. 4 to the expanded position of FIG. 3 is accomplished by sliding guide member 70 along the length of rod 60 in a right-to-left direction as drawn in said Figures. Rod 60 may be provided in a substantially horizontal orientation relative to a wearer standing upright. Preferably, rod 60 is downwardly angled from a horizontal plane whereby visor 20 is positioned lower relative to the ocular area of the wearer when in the proximate position of FIG. 4 and visor 20 is positioned higher relative to the ocular area when in the distal position of FIG. 3 . Slack fold 80 is formed in hood 10 just below visor 20 when guide member 70 is displaced from its FIG. 3 position to its FIG. 4 position. Note the lower half, or filter-including part of the novel hood, is recessed with respect to the top half, or visor-including part of the hood when said hood is in repose as illustrated in FIG. 3 . Note further that when hood 10 is in said position of repose, visor 20 is substantially co-planar with the front of filter 30 . When visor 20 is in its retracted position, as illustrated in FIG. 4, visor 20 is substantially co-planar with the back of said filter 30 . Significantly, as indicated by a comparison of FIGS. 3 and 4, the filter-including lower part of the novel hood has a fixed position that is unaffected by movement of the upper, visor-including part of said hood.
FIG. 5 is a front elevation view of an embodiment of the invention with two filters 30 . As in the first embodiment, slack fold 80 is formed in visor 20 when guide member 70 is slidingly displaced along the length of rod 60 in a direction toward visor 20 . A detailed view of of rod 60 is provided in FIG. 6 wherein notches 90 and 91 are formed in rod 60 . Said notches engage and secure guide member 70 and hence visor 20 at preselected retracted positions. In FIG. 6, spring 85 is sandwiched between forward support leg 60 a and guide member 70 . Spring 85 is under compression and therefore resiliently biases guide member 70 and visor 20 towards the ocular area of the wearer. In a preferred embodiment, the apparatus is packaged with the spring under tension whereby upon unpacking, spring 85 automatically moves guide member 70 and visor 20 towards the ocular area of the wearer (the proximate or retracted position). Alternatively, spring 85 may be under tension and positioned on the opposite side of guide member 70 to pull visor 20 to the proximate position.
In FIG. 7, fold line 100 in hood 10 is substantially parallel to visor bottom 21 and permits visor 20 to fold over filters 30 when guide members 70 are retracted along the respective extents of rods 60 . Planar surface 110 disposed between filters 30 provides a flat surface against which visor 20 is stored when hood 10 is folded in the manner depicted in FIG. 9 . Planar surface 100 may be integral to filters 30 or detachable when the hood is in an unpackaged state. Alternative means exist to lock each guide member 70 at a location on each rod 60 when visor 20 is in its retracted configuration. In FIG. 8, guide member 70 is secured to mounting member 61 that is in turn secured to filter 30 by hook and loop interface 73 , otherwise known under the brand name VELCRO. This embodiment eliminates rod 60 . Other embodiments may include utilizing snap buttons, peel-away adhesive, or any other mechanical coupling as known in the art to secure second end 72 of guide member 70 to mounting member 61 .
In the embodiments that employ rod 60 , it is preferred that rod 60 be formed of substantially rigid polymer construction to withstand heat, humidity and physical impact. Guide member 70 is preferably constructed of resilient elastomeric material that forms a slideable interference fit with rod 60 .
In FIG. 9, as mentioned above, visor 20 is folded over filter 30 to lie in flat, overlapping relation to planar surface 110 . Guide member 70 is flexed between first end 71 and second end 72 to accommodate the folding. Visor 20 is thereby protected from optically damaging creasing when so stored.
FIG. 10 is an embodiment of the invention utilizing a resilient tension spring 86 to interconnect guide member 70 to mounting member 61 . When the apparatus is in a packaged state, resilient tension spring 86 is pulled to an extended position under tension. When the apparatus is unpacked, spring 86 pulls the visor down and towards the ocular area of the wearer, thereby creating slack fold 80 .
In FIG. 11, filters 31 and 35 are secured to hood 10 in angled relation to visor 20 , threaded in opposite relation relative to one another and adapted to screw threadedly receive rings 32 and 37 respectively. Filters 31 and 35 are externally threaded and rings 32 and 37 are internally threaded. Securing points 33 and 38 on top of each ring 32 and 37 are coupled to guide members 70 whereby tightening of rings 32 and 37 pull visor 20 downward and towards the ocular area of the wearer.
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A protective apparatus including a flexible hood provided with a visor movable from a distal position to a proximate position relative to the ocular area of a wearer of the hood and a slack fold coincident to a bottom portion of the visor providing the visor with a range of movement defined by the distal and proximate positions.
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This is a continuation of application Ser. No. 727,436 filed Sept. 28, 1976 now abandoned.
BACKGROUND OF THE INVENTION
Although the invention will be disclosed as embodied in a fishing rod, it will become evident that the principles of the invention may be embodied in such objects as vaulting poles, whip antennas, flag poles, and other structures of a cantilever nature when the resistance to flexure of the free end is desirable to be increased automatically in proportion to the applied load.
It is recognized by anglers that the resistance to flexure of a fishing rod ideally be proportional to the size of the fish and/or the weight of a lure. For small fish the rod flexes readily and there is no good reason to use an oversized rod where a small one will do. Analogously, large fish are best caught with a large rod. However, in order to handle the larger fish as well as those which are smaller, the fisherman will frequently overburden himself. Consequently, a single rod having variable performance is a desirable objective.
Attempts have been made to attain the foregoing objective by the use of a hollow rod equipped with a longitudinally-manually-shiftable plug or core, for example, as disclosed in U.S. Pat. No. 3,570,164. However, in this case, the pliancy of the rod is a step function, depending on the selected relation between the core and body of the rod, whereas I have found that a rod having a smooth transition from a lower to a higher limit is easier to manipulate and responds automatically in a more truly proportional manner. In the said patent, shifting of the core away from or toward the tip consists in locating a tapered core member at one or another predetermined axial position within and transversely spaced from an identically internally tapered rod member. If the core member and rod member are thus spaced apart in all positions of the core member, no augmented resistance to flexure is to be seen and the advantages set forth herein as desirable are not attained.
DESCRIPTION OF THE INVENTION
The present invention provides two distinct ranges of response to flexure when force is applied to the distal end of a cantilever beam assembly by means of an inexpensive, uncomplicated construction. In substance, a fishing rod embodying the invention, regarded apart from the handle, reel and line guides, comprises a sleeve, desirably externally tapered from the handle toward the tip to constitute what is referred to herein as the outer member, within which is located an inner member which is also tapered, but with an apical angle larger or smaller than the apical angle of the outer member. The inner member may be of uniform diameter. The interior aspect of the outer member and the exterior aspect of the inner member are regarded in one embodiment as cones or conical shells although pyramidal or other configurations for either or both are within contemplation. The inner member may, alternatively, be solid. Moreover the inner member may be longer or shorter than the outer member.
The material of the outer member and core member may be any resilient material capable of bending 180° or more, e.g. Fiberglas, graphite, plastics composition, wood, metal, etc. or combinations thereof with and without binders or reinforcement, e.g. fabric. The core member is secured to the outer member over a localized area adjacent the butt end by any appropriate expedient, as by fitting and gluing one within the other. The load is applied to the tip end of the assembly. The outer and inner members are, as stated, fixed together at a common end, e.g. the handle, and the distal end of the inner member will lie between the tip and the fixed end. In the ordinary case the zone of bending will be somewhat beyond the handle, and the inner member or core element will terminate forwardly at a point which is located at between 35% and 65% of the distance measured from the handle toward the tip of the assembly. The inside surface of the outer member will define, with the core member, what may be regarded as a generally frusto-conical space of increasing annular cross section. That is to say, a transverse cross section taken at right angles to the longitudinal axis will show an annulus of gradually increasing area from the inward or fixed end of the assembly to the tip.
The conicity of the sleeve and the core member respectively are mutually independent and are so selected as to yield the desired flexure over a specified range of loads, usually expressed as power, action or speed of recovery for the various kinds of fishing, e.g. fly casting, bait casting, spinning, tournament accuracy casting, distance casting, surf casting, bottom fishing, trolling, etc. and for any particular kind and size of fish. The complete rod may comprise jointed sections or may be in one piece. It is to be understood that if the joint shall fall along the length of the core member, this latter will be provided with its own splicing means.
The present invention is not to be confused with the so-called "double-built" rod which comprises two rods secured together for their entire length by cement and is, therefore, a single rod of some greater stiffness that of a single-built rod.
The tip of the invention rod may be extremely flexible, i.e. sensitive, to provide a rod such that the fisherman can feel the strike of a very small fish or the nibbling of a larger one, making for greater versatility. The transition in the resistance of the rod in passing from the single rod, i.e. core member inactive, through to the double rod, i.e. core member active is, in the case of the invention rod, smooth and will enable the fisherman to use just the right amount of power. Stated otherwise, the improved rod provides a greater sense of control over the fish which is not available with conventional rods. In the case of the conventional rod the fisherman has to contend with whatever stiffness exists, irrespective of the size of the fish and, if the rod is so stiff that it will not bend sufficiently, the fisherman fails to have the protection of the cushioning effect which would otherwise be available.
The mid and butt-sections can be made to have as much power as desired, by suitable selection of tapers, diameters, wall thicknesses and relative lengths of the inner and outer members. In the case of the invention, a rod of smaller diameter and/or shorter length will function as well as a conventional rod of larger diameter and/or greater length, and will safely and repeatedly bend beyond the usual safe limit of 90°.
Embodiments of the invention rod have been found to be less tiring to the angler. It will be recognized that a fishing rod must have "backbone" to successfully handle fish of any size, i.e. weight category. Conventional rods are rated and described by their manufacturers as capable of handling fishing lines with a 20-pound test strength or fishing lines having a 40-pound test strength. The backbone of strength built into each model is designed to withstand the upper limit of the load imposed on the line. As the conventional rod has no compounding stiffening quality, it is constructed with too much rigidity to handle with effiency any loads imposed which are less than the top rated limit of the rod. The rod bends to fight the fish. However, with the invention rod the bending is compound or, otherwise stated, two rods are built into one, the inner member coming into play only when called upon, and only to the extent called upon, vis., in a manner to supplement the action of the outer member.
With respect to the foregoing, the "action" of a fishing rod may be described best as the curvature it assumes when under load, and "recoil power" may be defined as the ability to cast a weight through the air.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a medial, longitudinal cross section of a fishing rod embodying the principles of the invention in unloaded or relaxed condition;
FIG. 2 is a view similar to FIG. 1, but with the tip of the rod in bent condition;
FIG. 3 is a cross section taken on the line 3--3 of FIG. 1;
FIG. 4 is a cross section taken on the line 4--4 of FIG. 1;
FIG. 5 is a combined elevation and cross section of an archery bow embodying the principles of the invention;
FIG. 6 is a cross section taken on the line 6--6 of FIG. 5;
FIG. 7 is a cross section taken on the line 7--7 of FIG. 5;
FIG. 8 is a side elevation of another embodiment similar to FIG. 1, but comprising a core member which is itself hollow and has the same taper in both members;
FIG. 9 is another modification with the members having different conical form;
FIG. 10 is another modification in which the inner member is a straight tube;
FIG. 11 is a modification in which the inner member extends from the tip of the rod, where it is secured, to a point which is spaced away from the butt end.
In these drawings the degree of taper and wall thicknesses have been exaggerated for clarity.
Adverting to the drawing I have shown (FIG. 1), by way of example, a double cantilever rod assembly for use as component of a fishing rod to provide the several advantages described above. The assembly comprises a tubular conical body or outer member 10 having uniform wall thickness. Alternatively, the wall may have a gradually decreasing thickness from the butt end 12 toward the tip 13 depending upon the characteristics to be imparted.
Within the body 10 there is an inner or core member 16 having, at the butt end, a snug fit with the outer member 10. The core member is a slender conical shell secured to the outer member, as shown. The joint between the body 10, member 16 and butt end or handle 17 may be of any convenient construction as long as the parts have no tendency to separate when subjected to the bending forces imposed on the rod during use. Inasmuch as the handle, reel support and grip, if any, are conventional, elaboration is deemed unnecessary. Referring to FIGS. 1 and 2, it will be noted that the areas of contact between the basal ends of the inner and outer members 10 and 16 are uninterrupted as, for example, by reducing the diameter of the inner member. To do so, would necessitate a shoulder at the place where the diameter of the inner member is reduced. Thus, a less abrupt transmission is avoided which, otherwise, would create a region of concentrated stress, possibly leading to a fracture at said reduced area.
At this juncture it is pointed out that the body 10 and parts 16 and 17 are axially non-displaceable with respect to each other and to the butt end 17. As described thus far the rod, upon being subjected to a load, i.e. a hooked fish, will be deflected and the extent of such deflection will be a function of the dead weight of the fish plus loading due to its efforts to dislodge the hook. However, as flexing continues, i.e. gradual increase in load, the tip 20 of the core member 16 is brought into contact with the interior of the outer member 10 and part of the load is absorbed by the core member 16.
As a consequence members 10 and 16 begin to function jointly, i.e. bending of the sleeve 10 will then compound with bending of the core member 16. Thus, the resistance to bending exhibited by the sleeve member 10 alone now increases and the assembly becomes gradually stiffer or, otherwise stated, the resistance of the core member 16 is added to the resistance of the sleeve 10 with the advantages hereinbefore set forth.
FIGS. 5 to 7 depict application of the principles of the invention to an archery bow. It is believed that details of construction and operation will be evident from the drawing and the preceding description. In this case a typical transverse cross section will be essentially rectangular as shown to conform to a common type bow. Reference numerals 10a and 16a indicate the outer sleeve and core member respectively. The drawing shows a rectilinear cross-section. The act of drawing the bow will bend the composite cantilever assembly perpendicular to the altitude of the shorter sides of the cross-section. The cross-sectional portions 10a and 16a read with respect to FIGS. 6 and 7 indicate a spacing of the inner lever within the outer lever. The spacing shown in FIG. 7 is by way of example, and the cross-sectional portion 16a could be positioned other than is shown in this figure, depending upon the amount of additional resistance desired to be imparted to the composite cantilever bow assembly. In order to preclude relative shifting of these two parts in a longitudinal sense, adhesive, rivets, screws or equivalent fastening means (not shown) may be employed at some region at the mid-point of the overall length of the bow in order to insure that the bending function of the inner and outer members is not interfered with.
FIGS. 8, 9 10 and 11 show various modifications of the composite cantilever fishing rod assembly of the present invention, the constructions of which are believed to be apparent from the description of the remaining figures. In the case of the inner member, the reference numeral 16 becomes 16(b), 16(c), and 16(d). The reference numeral 25 in FIG. 9 indicates an inner member having a solid cross-section. Since no change in the configuration of the outer member is made in these figures, the same reference numeral, namely 10, has been used. With respect to FIG. 11 particularly, the joint flexing movement of the inner and outer lever members is confined essentially to a region between the distal end of the rod and the point approximately one-third the distance from the basal portion to the distal tip. For some uses, flexer is desirably confined to a longitudinal part of the composite cantilever fishing rod adjacent the tip end.
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A resilient assembly comprising two resilient members so constructed as to provide a selected stiffness factor. In its fundamental form the assembly, when embodied in a practical structure, such as a fishing rod, and subjected to a load transversely applied to one end or along its length, functions similarly to a conventional tapered fishing rod up to some predetermined limit of flexure and, upon reaching such limit, additional resistance to flexure is introduced automatically.
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FIELD OF THE INVENTION
The invention relates to an improved rotary device intended for catalytic cleaning of gaseous effluents.
The invention finds applications notably in heat exchange systems or in systems suited for cleaning air loaded with substances such as volatile organic compounds (V.O.C.), which can be oxidized and eliminated by thermal or catalytic incineration.
BACKGROUND OF THE INVENTION
Patent FR-A-2,720,488 describes a device intended for heat exchange and cleaning of polluted gases such as VOC by thermal and/or catalytic effect. It comprises a housing or cage, a pipe for feeding polluted effluents into the cage, another pipe for discharging the processed effluents from the cage, a ring containing an inert charge of solid particulate materials exhibiting a large heat exchange surface (silica, granite or lighter materials such as metal honeycomb structures or others, or cryogenic nodules for negative temperatures, etc.) which is arranged within the cage. The ring can be divided into several parts by means of an inner partitioning or, in some cases, serve as a support for a certain number of baskets. Motive means are used to drive the ring and the cage into a rotating motion with respect to each other around a vertical axis (either the ring rotates, the cage being stationary, or the ring is stationary and the cage rotates around it). A first heat transfer occurs between the effluents and the inert charge in a first angular sector of the ring. A second heat transfer occurs between effluents and the charge in the ring in a second sector of the ring. A thermal reactor possibly provided with a catalyst bed is arranged in this central part in order to burn the polluting substances in the effluents channelled by the first angular area.
Patent FR-A-2,728,483 describes a device intended for catalytic cleaning of effluents polluted by VOC comprising, within a stationary cage, a rotating ring of vertical axis comprising an annular catalyst bed covering the inner wall thereof and an annular charge, outside the catalyst bed, of a material exhibiting a large heat exchange surface. The effluents flow twice through the catalyst bed on either side of the central zone. A burner is placed above the central reaction zone and it is connected to a fuel injection pipe by means of a rotary joint. It is used to heat the incoming effluents so as to reach an autothermal working point, or possibly to provide makeup heat in cases where the polluting VOC compound content is insufficient to reach it.
SUMMARY OF THE INVENTION
The device intended for catalytic cleaning of gaseous effluents according to the invention comprises a housing or cage, a ring of vertical axis arranged within the cage containing a thermal charge of materials exhibiting a large heat exchange surface, and motive means for driving the ring in a rotating motion with respect to the cage, a catalyst-bed reactor placed in the central part of the device for cleaning the effluents, at least one pipe for feeding effluents into the cage and at least one pipe for discharging effluents from the cage, the ring comprising at least a first sector allowing continuous communication between the feed pipe and the central part of the cage, and at least a second ring sector allowing continuous communication between the central part of the cage and the discharge circuits.
The device is mainly characterized in that it comprises heating elements embedded in the catalyst bed (which is preferably arranged in the ring against an inner wall thereof) and connecting means intended to connect temporarily these heating elements to a power supply unit external to the device long enough to bring the catalyst bed to a temperature sufficient to trigger a reaction of catalytic oxidation of the polluting substances, and means for injecting fluids into the effluents fed in the device, in order to control the temperature prevailing in the central area during effluent cleaning operations.
The catalyst bed heating means comprise resistors for example.
The fluid injection means can comprise, for example, an injection circuit associated with the feed pipe in order to inject a fuel into the effluents to be cleaned and/or an injection circuit, also associated with the feed pipe, in order to inject a non-inflammable liquid such as sprayed water, for example, into the effluents to be cleaned so as to cool the reactor.
According to an embodiment, the device can also comprise particle filtering means associated with the ring, consisting for example of a filter layer externally added to said ring so as to retain the particles likely to clog the thermal mass and/or the catalyst bed. It may be a removable bed of metallic, ceramic, composite materials, more generally of woven or non-woven materials whose density is suited to the stopping power sought.
The device affords many advantages. Using heating elements in intimate contact with the catalyst, which are temporarily connected to an external power supply unit prior to starting the cleaning operations proper, greatly simplifies the making and the use of the device.
Preheating of the catalyst is comparatively much faster than with the indirect warm air circulation heating means previously used where the reactor is brought to a high operating temperature through circulation of air heated by means of a secondary burner. Not only because heating is more effective as a result of the close contact between the heating elements and the catalyst, but also because the preheating sequence is much shorter. In fact, the regulations in force require to observe codified safety sequences for the feeding and the lighting of industrial burners which lengthen implementing operations.
The preliminary heating stage can be carried out outside the normal operating periods of the device, at night or at week-ends, and at a lower price by taking advantage of off-peak tariffs. Connection with the power system is simplified since it is established only when the ring is immobilized. Since the means intended for operating temperature control are fluid injection circuits (fuel and sprayed water for example) associated with the effluent feed pipe, they are readily installed. The layout of the device favours a manufacturing and upkeep cost decrease and simplifies the safety means to be implemented.
The process according to the invention implemented by means of the device allows cleaning of gaseous effluents loaded with polluting substances by catalytic incineration, by means of the aforementioned device for example. It is characterized in that it comprises successively a preliminary stage of heating the catalyst bed reactor through temporary connection, to a power supply unit external to the device, of heating elements embedded in the catalyst bed and, after disconnection of the heating means, an operating stage comprising establishing a permanent circulation of effluents to be cleaned through the ring, rotation of the ring with respect to the cage and thermal control of the autothermal reaction by controlled injection of a fuel and/or of at least one non-inflammable coolant in the device.
BRIEF DESCRIPTION OF THE DRAWING
Other features and advantages of the improved device according to the invention will be clear from reading the description hereafter of non limitative embodiment examples, with reference to FIG. 1 which diagrammatically shows a cross-sectional view of an embodiment of the device.
DETAILED DESCRIPTION OF THE INVENTION
Device comprises (FIG. 1) a ring 1 of vertical axis arranged within an external metal housing or cage 2 of cylindrical shape for example. The diameter of cage or housing 2 is larger than that of ring 1. The latter is for example off-centre with respect to cage 2. On either side of the diametral plane containing the vertical axis 3 of the ring, and in a limited circular sector, cage 2 comprises a lateral wall portion 4 substantially tangential to the lateral wall of the ring. The inner space of the cage around ring 1 on either side of wall portion 4 thus comprises two round zones of variable section Za and Zb. They communicate respectively with a feed pipe 6 intended for delivery of the gaseous effluents to be cleaned and a discharge pipe 7 intended for discharge of these effluents after cleaning.
Ring 1 is provided with an inner partitioning consisting of evenly distributed radial plates or angular sectors 8. A first angular sector A delimited by one or more radial plates 8 channels the effluents to be cleaned and fed into the convergent zone Za towards the central zone Zc of the ring (flow Fe). A second angular sector B communicates the central zone Zc of the ring with the divergent zone Zb and with discharge pipe 7 (flow Fs).
The inner wall of the ring is thoroughly covered with an annular catalyst bed consisting of a particle bed or possibly of a honeycomb structure catalyst. The effluents must flow through the catalyst bed a first time to reach the reactive central zone and a second time to leave it and flow through the opposite angular zone prior to being discharged outside.
Heating means are used to heat catalyst bed 9. Resistors R (FIG. 2) are for example used and arranged within the catalyst bed, around the inner circumference of ring 1, connected to electric connection means (not shown) that can be connected to the power system either manually or by means of a connecting robot of a well-known type.
An inert mass M consisting of a material with a large heat exchange surface to is distributed in the remaining part of ring 1, outside this catalyst bed 9 and between partitioning plates 8. It may be ceramic or metal balls, turning chips or machining chips, random or stacked packing, an alveolate structure with regular or irregular alveoli such as a honeycomb structure, knitted, woven or needled metal or ceramic mats, etc. A honeycomb structure such as that described in patent FR-2,564,037 registered by the applicant can for example be used, or a stone structure.
In order to facilitate construction and loading, the ring can also be designed to serve as a support for a certain number of parallelepipedic baskets 10 spaced out as shown in FIG. 1.
According to a preferred embodiment, particle filtering means can be added outside the ring, so as to stop the dust and particles likely to eventually clog thermal mass M and catalyst bed 9. These filtering means can consist of a filter layer 11 for example in the form of a readily removable 3 to 10-cm thick preformed mat of metal, ceramic or composite materials, or more generally of a woven or non-woven material whose density is suited to the stopping power sought. This filter layer takes part in the heat exchange as a result of the large surface area thereof.
In the diametral plane of symmetry containing the vertical axis 3 of the ring, the narrowness of the space remaining between the ring and the cage, as a result of the off-center position thereof and of the bulging wall portion 4, generates a sufficient pressure drop to prevent direct peripheral communications between the two upstream and downstream spaces or zones Za and Zb other than through central zone Zc. Joints or flaps 12 can possibly be placed on the periphery of the ring where the temperature is relatively low in order to perfect the seal.
The ring and the cage are closed in the lower and tipper parts thereof by plane plates 13. Several blade joints (not shown) simultaneously resting between the corresponding plates of the ring and of the cage prevent parasitic bypass flows between zones Za and Zb.
Motive means (not shown) situated above the cage for example are coupled with the pin 3 of the ring so as to drive it into rotation with respect to the cage.
The intermediate angular sector Zd delimited by the wall portion 4 of the cage preferably comprises an opening for a fresh air injection pipe 14 intended to drain the foul effluents through the thermal mass and the catalyst in the few angular sectors of the ring going past it prior to each inversion of the direction of flow. After flowing through the drained sectors, the purge air reaches the central zone where it is carried along with the main flow towards zone Zb through ring 1.
In sector Ze opposite sector Zd, the cage comprises another pipe 15 for a fresh air injection intended to control, if need be, the temperature of the catalytic reaction if it rises too much.
The device also comprises a means 16 for injecting a fuel such as LPG (liquid propane gas) for example, and a means 17 for injecting a coolant such as sprayed water for example to complete the action of the air injected through pipe 15.
Operation
A first stage consists in bringing catalyst bed 9 to a sufficient temperature (200 to 300° C. for example) so that the oxidation reaction can be triggered in the presence of VOC. The connection means connected to the resistors R intended to heat the catalyst bed are linked up with an external source of energy such as the power system. The operation is preferably performed outside the normal operating periods of the device by taking advantage of reduced-rate periods (at night for example).
Once the reaction temperature (300° C. for example) has been reached, the device is started, ring 1 is driven into rotation and an effluent circulation is established within cage 2. The effluents flow twice through catalyst bed 9, a first time to reach the central zone of ring 1 as they flow in from delivery zone Za, a second time to reach discharge zone Zb. The oxidation reaction is set off spontaneously in the presence of the VOC particles in the effluents. It is exothermic and adjusted so as to release enough energy to substantially compensate for the heat dissipation. According to the thermal efficiency of the thermal charge or inert mass M and to the operating temperature, a proportion of 0.3 to 1 g of VOC per m 3 of effluents is generally sufficient for an autothermal operation.
Fresh air can be injected through pipe 15 so as to control at first the temperature of the catalytic reaction if it rises too much. If this injection is insufficient to provide the required heat control, a sprayed liquid such as water is injected through pipe 17 and mixed with the effluents to be processed.
Means 16, 17 intended for injection of fuel and of coolant through feed pipe 6 allow to compensate for the temperature variations linked with the variations in the polluting compounds (VOC) content of the effluents. If the content decreases, a fuel injection is performed so as to raise the temperature prevailing in the central part of cage 2. If the temperature in the reactive zone rises under the effect of a VOC content increase, a coolant (sprayed water for example) injection is performed so as to bring it back to a normal operating temperature range.
After double passage through the catalyst bed, on either side of central zone Zc, the VOC are converted by the reaction into various combustion products CO 2 , H 2 O, N 2 mainly, SO x and NO x as traces.
The high-temperature gases coming from the reactive zone flow through the part of charge M situated in the angular sector B of the ring and yield a good part of their calories thereto.
The rotation of ring 1 with respect to cage 2 progressively drives the heated elements towards angular zone A where they can yield to the gases flowing in through feed pipe 6 part of the heat energy accumulated.
The layout of the embodiment described above, with the rotating ring 1 provided with a catalyst bed 9, heating means, e.g., resistor R integrated in catalyst bed 9 and means of thermal control through fluid injection, allows the manufacturing and operating costs of the device to be considerably decreased in relation to prior embodiments. The heating means R of the catalyst bed being disconnected prior to starting the device, the rotary connectors that are otherwise required to feed them are thus avoided. The temperature control means (fuel injectors 16, water injector 17 for example) are simply connected to feed pipe 6.
The catalytic reactor consists here of a bed 9 placed in rotary ring 1. Without departing from the scope of the invention, a catalytic reactor placed in a general way in the central zone Zc of the ring, also provided with heating means also working during preheating stages prior to the cleaning operations and disconnected prior to starting the device, can be used.
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The invention relates to a cleaning device wherein polluted effluents are passed into a cage (2) where a partitioned ring (1) of vertical axis, containing a charge (M) of a solid material exhibiting a large heat exchange surface and, against the inner wall thereof, a catalyst bed (9), rotates. An autothermal working point is reached by including in the catalyst bed heating means (resistors for example) that are temporarily connected to the power supply system, after which the cleaning operations with rotation of the ring and effluent circulation are launched. Heat control is thereafter provided by controlled injection into the effluents of either a fuel or sprayed water for example by means of injectors (15, 16). The device can be applied in the field of incineration of VOC for example in industrial effluents.
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COPYRIGHT NOTICE
[0001] A portion of the disclosure of this patent document contains or may contain copyright protected material. The copyright owner has no objection to the photocopy reproduction by anyone of the patent document or the patent disclosure in exactly the form it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
TECHNICAL FIELD
[0002] This invention relates to environmentally friendly hybrid microbiological control compromising a physical method through fine filtration which removes nutrients, bacteria and suspended solids from re-circulating cooling systems and hence is reducing significantly the biocide consumption and chemical microbiological treatment programs previously required to obtain similar levels of effectiveness.
BACKGROUND
[0003] Particle separation can be performed based on size exclusion. Large size particles are easily removed by sand filtration. However, only filters with small pore size, such as membranes or certain granular media, can separate colloidal particles, bacteria, macromolecules, small molecules, or even ions. Membrane is a physical barrier (thin layer) capable of separating materials as a function of their physical and chemical properties in the presence of an applied driving force. Granular media are formed from small particles and have a small effective pore size.
DEFINITIONS
[0004] Biocides: are active substances, and preparations containing one or more active substances, put up in the form in which they are supplied to the user, intended to destroy, deter, render harmless, prevent the action of, or otherwise exert a controlling effect on any harmful organism by physical, chemical or biological means.
Oxidising Biocides Oxidising biocides are generally non-selective, they can oxidise all organic material including micro-organisms. They oxidise the cell components of organisms, the thinner the cell wall the more vulnerable in organisms is towards oxidising biocides. Because oxidising biocides are non-selective, resistance does not develop. Examples of oxidizing biocides include halogens, active oxygen sources.
Non-Oxidising Biocides: Unlike oxidising biocides, non-oxidising biocides are selective in their mechanism of attacking micro-organisms. They interfere with the metabolism of the organism, disrupt the cell wall, or prevent multiplication. To be effective, typically higher concentrations are required than for oxidising biocides. Micro-organisms can develop resistance/tolerance when the biocide is longer in use, therefore it is good practice to alternate non-oxidising biocides.
Biodispersants and biodetergents Are surface-active chemical, that exibit generally no biocidal characteristics on their own, prevent micro-organisms from attaching to surfaces and accelerate detachment of a biofilm by loosening the slime matrix
Fine Filter is a physical barrier capable of separating materials by their physical and chemical properties. A fine filter is capable of separating particles from fluids in part or all of the range of a few mm to 0.1 nm particle size.
Membrane is a physical barrier capable of separating materials as a function of their physical and chemical properties when a driving force is applied across the membrane.
Granular media comprise particles arranged in a container so as to from a physical barrier capable of separating materials by their physical and chemical properties when the materials are forced to move through the granular barrier. The granular medium may be one size or a mixture of sizes. The granules may be silica, anthracite, activated carbon, or other inorganic or organic material.
[0006] Depending on the pore size one can distinguish the following membrane techniques: microfiltration (MF), ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO).
[0007] Ultrafiltration (pore size 0.01-0.1 μm) is used to retain particles of a size of a few nanometres whereas microfiltration, which employs porous membranes with pore diameters between 0.05-10 μm is able to separate particles in the μm size range.
[0008] Ultra- and Micro-filtration are pressure-driven barriers to suspended solids and bacteria to produce water with high purity. Suspended solids and solutes of high molecular weight are retained, while water and low molecular weight solutes pass through the membrane. The water and other dissolved components that pass through the membrane are known as the permeate. The components that do not pass through are known as the concentrate. Depending on the Molecular Weight Cut Off (MWCO) of the membrane used, macromolecules may be purified, separated, or concentrated in either fraction.
[0009] Because only high-molecular weight species are removed, the pressure differential across the membrane surface is relatively low. Low applied pressures are therefore sufficient to achieve high flux rates from an UF/MF membrane. Flux of a membrane is defined as the amount of permeates produced per unit area of membrane surface per unit time. Generally flux is expressed as liter per square meter per hour (LMH). UF and MF membranes can have extremely high fluxes but in most practical applications the flux varies between 10 and 100 LMH at an operating pressure of about 0.1 bar to 4 bar
[0010] UF/MF membrane modules come in plate-and-frame, spiral-wound, and tubular configurations. The configuration selected depends on the type and concentration of colloidal material. For more concentrated solutions, more open configurations like plate-and-frame and tubular are used. In all configurations the optimum system design must take into consideration the flow velocity, pressure drop, power consumption, membrane fouling and module cost.
[0011] A variety of materials have been used for commercial polymeric UF/MF membranes like polysulfone (PS), polyacrylonitrile (PAN), polyerthersulfone (PES), cellulose acetate (CA) and polyvinylidene fluoride (PVDF). Also inorganic membranes are used like ceramic membranes.
[0012] Ultrafiltration is the membrane separation method with the broadest application spectrum. It is increasingly used in drinking water treatment, removing major pathogens and contaminants such as Giardia lamblia, Cryptosporium oocyts and large bacteria. However, soluble components such as salts and low molecular organic substances usually cannot be retained with ultrafiltration membranes.
[0000] There are several factors that can affect the performance of an UF/MF system.
1. Flow Across the Membrane Surface. The permeate rate increases with the flow velocity of the liquid across the membrane surface. Flow velocity if especially critical for liquids containing suspensions. Higher flow also means higher energy consumption and larger pumps. Increasing the flow velocity also reduces the fouling of the membrane surface. Generally, an optimum flow velocity is arrived at by a compromise between the pump horsepower and increase in permeate rate.
2. Operating Pressure. Permeate rate is directly proportional to the applied pressure across the membrane surface. Most membrane modules have an operating pressures limit due to the physical strength limitation imposed to the membrane module.
3. Operating Temperature. Permeate rates increase with increasing temperature due to reduced liquid viscosity. It is important to know the effect of temperature on membrane flux in order to distinguish between a drop in permeate due to a drop in temperature and the effect of other parameters.
Micro and ultrafiltration process takes place at low differential pressure making it a low energy consuming process and MF/UF is removing nutrients and bacteria from the water; the cooling system biofouling potential is retarded hence reducing biocide consumption
SUMMARY
[0013] The current invention describes the following key aspects:
1. It is an advantage of the invention to provide low differential pressure. 2. It is an advantage of the invention to provide removal of fine silt, turbidity, particulate TOC, nutrients reducing biological growth. 3. It is an advantage of the invention to provide high bacteria removal efficiency. 4. Provides a method for regeneration by back flushed or air scrubbed to remove the fouling layer.
DETAILED DESCRIPTION
[0018] The current invention describes a method for microbiological control in cooling systems where in a recirculating fluid containing a biocide and is passed through a fine filtration system wherein the recirculating fluid may be diverted to a side stream then passed through the fine filtration system.
[0019] The inventions fine filtration system contains membranes that have a pore size at 5 or less μm preferable having a pore size from 0.01 to 0.5 μm. The inventions fine filtration system may also contain membranes that are micro ultra-filtration membranes. These membranes can be regenerated by back flushed the system or by air scrubbing the system.
[0020] The claimed invention uses an oxidising biocide that is preferably one or more of the following: chlorine, hypochlorite, ClO2, bromine, ozone, hydrogen peroxide, peracetic acid and peroxysulphate. Additionally the invention may use a non-oxidising biocide that is preferably one or more of the following: glutaraldehyde, dibromo-nitrilopropionamide, isothiazolone, quaternary ammonium, terbutylazine, polymeric biguanide, methylene bisthiocyanate and tetrakis hydroxymethyl phosphonium sulphate. The claimed invention may also use a mixture of an oxidising biocide and a non-oxidising biocide with the preferred examples listed above.
EXAMPLES
[0021] The foregoing may be better understood by reference to the following examples, which are intended to illustrate methods for carrying out the invention and are not intended to limit the scope of the invention.
[0022] It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the invention and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.
[0023] Microbiological control, biocide usage, were followed in a pilot cooling tower (PCT) in the presence and absence of a physical method membrane filtration (ultrafiltration) that, due to size exclusion, is removing particulate matter including bacteria, with a size larger then 0.010□m.
Ultrafiltration Device:
[0024] An ultrafiltration device was rented from Norit BV. The main characteristics of the unit and membrane are presented in the appendix. The unit is composed from a tank (volume 25 l) where the water is concentrated. A level controller controls the level of the water in the tank. From the tank the water is pumped with the help of pomp PO1 over the membrane. The concentrated is passed through a cooling system and then is returned to the storage tank. The permeate is added to the basin of the cooling tower.
[0025] To prevent membrane fouling a minimal flow velocity of 2 m/sec was run over the membranes. Opening or closing of valves V1 and V2 adjusted the flow. Valves V1 and V2 were never closed completely. In addition, according to the supplier specifications, the feed pressure flow in P1 was not exceeding 1 bar (blow up of membranes). The membranes should never become dry after the first use (always keep them wet)
[0026] The cross-flow membrane was an 8 mm hollow fibber, inside-out filtration. The pilot unit was initially equipped with 2 membrane modules with a surface are of 0.15 m 2 each, total membrane surface is 0.3 m 2 .
UF Membrane Cleaning for Start-Up:
[0027] When new membranes were used, first the glycerin that keeps the membrane wet and biocide were rinsed out (to prevent degradable COD to enter the cooling tower as additional food source). The tank 1 (see FIG. 1) was filled with DI water and recirculated over the membranes according suppliers (Norit) recommendations. After 30 minutes the water is drained. The procedure is repeated at least three times. Finally the system is drained, valve nr 301 is closed and tank nr 1 is filled with water from the PCT basin while permeate is re-introduced into the PCT basin.
[0000] Pilot Cooling Tower (PCT) Tests with and without Membrane Device:
[0028] Cooling water hybrid physical/chemical microbiological treatment performance test was run using the Nalco standard PCT equipment with a setup. The volume of the basin was 200 L. For the base line an extra tank of 25 L was added to the basin, to simulate tank 1 when UF device was used. The tank 1 was heated to 30° C. temperatures similar to tank 1
[0029] The PCT test was run using metal tubes. All tubes were put in service after thorough degreasing, without any pre-passivation. Coupons were also included in the test. The PCT test was started without heating for the first 12 hours to allow initial corrosion reactions to come to rest. After this, heat was applied as described in Table 3. The test was started with cycled up water. Cooling water treatment 3DT165 product were dosed based on the Nalco Trasar technology. Blowdown was controlled by 3DTrasar based on conductivity set point when no membrane unit was in use.
[0030] When UF unit was running, the blow-down was set manually using a pump and once per day removing the concentrate from the tank 1 . The total volume of the blow-down was equivalent to the blow-down controlled by the 3DT unit.
[0031] The PCT was inoculated with cultured bacteria ( Pseudonromas ) to reach microbiological levels of about 10 5 cfu/mL. The inoculation was done at the beginning of each test. Liquid nutrients (Nutrients broth 4 g/L, supplier Oxio) were added to the system with a speed of 0.01 g/L/day continuously. Microbial control was carried out using hypobromite. The biocide dosage was done based on ORP control.
[0032] Make-up water chemistry was checked using ICP. Relevant parameters of the recirculating cooling water were analyzed or verified using field test methods on a daily basis. Following parameters were tested routinely: pH, M-alkalinity, conductivity, calcium and total hardness, ortho phosphate, total phosphate and polymer level.
PCT-Ultrafiltration
[0033] To the PCT basin the UF unit was mounted. Water from the basin was added continuously to the tank 1 of the UF unit. The level of the water in the tank was maintained constant using a level controller. The pomp P 02 was removing continuously a volume of 1.4 l/h as blow-down and disposing 101/day concentrate from tank 1 . The permeate is re-introduced into the basin. The permeate flow was kept at 20-25 l/h. When the permeate flow dropped about 15% from the initial values. A cleaning procedure was performed.
UT Unit Cleaning Procedure:
[0034] UF unit was cleaned during the case study 1 everyday. The same procedure is followed also for the case study 2 with the difference that cleaning procedure was applied only when the permeate flow dropped below 15% from the initial permeate flow. First, the feed water is closed while the permeate is inserted to the cooling tower basin. When the concentrated has a volume of about 10 L, the permeate tube is removed from the basin and it is introduced to the tank. The concentrate is removed and disposed to the drain. The tank was filled with DI water, biodetergent and biocide (hyphochlorite) and recirculated in agreement with suppliers (Norit) recommendations. The permeate water and recirculated water are kept in the tank. After 30 minutes, the pomp is stopped and the water is drained. Clean DI is added to the system and is recirculated over the UF membrane. The procedure is repeated at least three times. Finally the system is drained, valve nr 301 is closed and the tank nr. 1 is filled with water from the basin while permeate is re-introduced into the PCT basin.
Example 1
ORP 260 mV
[0035]
[0000]
Biocide Use g/h
TVC [cfu/ml]
Days
without UF]
with UF-
without UF]
with UF-
11
0.951
1.04
12
1.111
0.97
3.70E+05
1.03E+04
13
0.82
4.20E+05
1.38E+04
14
1.15
5.00E+05
6.00E+03
15
0.642
0.95
6.40E+02
16
0.745
17
0.875
0.83
1.80E+05
1.33E+03
18
0.61
2.60E+05
4.30E+03
19
0.728
0.86
3.00E+05
3.40E+03
Average
0.84
0.90
3.38E+05
5.68E+03
Example 2
ORP 200 mV
[0036]
[0000]
Biocide Use g/h
TVC [cfu/ml]
Days
without UF]
with UF-
without UF]
with UF-
11
0.433
3.60E+04
12
0.592
0.326
3.80E+04
13
0.241
1.71E+05
7.80E+04
14
2.30E+05
8.50E+04
15
0.633
1.42E+05
6.80E+04
16
0.311
1.49E+05
17
1.46E+05
18
0.556
0.339
5.10E+04
19
0.600
0.208
5.50E+04
Average
0.5628
0.285
1.03E+05
1.05E+05
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This is a method that is an environmentally friendly hybrid microbiological control compromising a physical method through fine filtration, which removes nutrients, bacteria and suspended solids from open recirculating cooling systems. The method for microbiological control in cooling systems wherein a recirculating fluid containing an oxidising or a non-oxidising biocide or a mixture of an oxidising and a non-oxidising biocide and is passed through a fine filtration system resulting in reduced microbiological matter, suspended solids and nutrients.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to battery packs and more particularly, to an attachable battery pack detachably connectable to an intelligent cell phone (such as, iPhone or Google phone) for use a spare battery and screen protector.
2. Description of the Related Art
Regular cell phones allow replacement of the rechargeable battery. However, certain single-piece commercial intelligent cell phones (such as, APPLE-iPhone or Google phone) do not allow replacement of the built-in rechargeable battery. When it is necessary to repair or replace the built-in rechargeable battery of an intelligent cell phone of this kind, the user must send to the intelligent cell phone to the distributor for repair or replacement by a technician. Further, when the power of the built-in rechargeable battery of an intelligent cell phone of this kind is used up and no any external power source is available, the intelligent cell phone becomes operable. Further, due to a single piece design, the screen of an intelligent cell phone of this kind tends to be scratched accidentally.
SUMMARY OF THE INVENTION
The present invention has been accomplished under the circumstances in view. It is one object of the present invention to provide an attachable battery pack, which is attachable to an intelligent cell phone for use as a spare battery. It is another object of the present invention to provide an attachable battery pack, which is attachable to an intelligent cell phone for screen protection.
To achieve these and other objects of the present invention, an attachable battery pack comprises a body having a static flocking fabric cover face on its one side and a genuine leather covering on its other side, a clamp pivotally connected to one end of the body for detachably fastening to an intelligent cell phone for enabling the body to be closed on the screen of the intelligent cell phone or opened from the intelligent cell phone, an electrical connector, which is connected to the power jack of the intelligent cell phone after clamping of the clamp on one end of the intelligent cell phone, a power switch for charging control and an indicator light for charging indication.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of a commercial intelligent cell phone.
FIG. 2 is an oblique elevation of an attachable battery pack in accordance with the present invention.
FIG. 3 corresponds to FIG. 2 when viewed from another angle.
FIG. 4 is a schematic drawing of the present invention, illustrating the attachable battery pack attached to an intelligent cell phone.
FIG. 5 corresponds to FIG. 5 , illustrating the attachable battery pack closed on the intelligent cell phone.
FIG. 6 is a schematic sectional view of a part of FIG. 5 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1 , an intelligent cell phone 10 (for example, APPLE-iPhone) is a single-piece member having a built-in rechargeable battery (not shown) that is not detachable and a power jack 11 located on one side thereof (for example, the bottom side) for the connection of a charging cable to charge the built-in rechargeable battery with an external power source.
Referring to FIGS. 2 and 3 , an attachable battery pack 20 is shown attachable to an intelligent cell phone 10 . The attachable battery pack 20 comprises a flat body 29 configured for use as a screen cover for the intelligent cell phone 10 . The body 29 has built therein a high-quality, charging and discharging Li-polymer battery cell and a charging circuit (this arrangement is of the known art and not within the scope of the invention), a static flocking fabric cover face 24 covered over the inner side thereof (the side to be covered on the screen of the intelligent cell phone 10 ) by means of static flocking technology for protecting the screen of the intelligent cell phone 10 , a genuine leather covering 28 covered over the outer side thereof (see FIG. 5 ) to exhibit an image of noble and high level.
The attachable battery pack 20 further comprises a clamp 21 pivotally connected to one end of the body 29 , an electrical connector 22 located on the clamp 21 and electrically connected to the Li-polymer battery cell and the charging circuit in the body 29 , and a springy hook 23 extended from the other end of the body 29 .
The attachable battery pack 20 further comprises a power switch 25 located on one lateral side of the body 29 , a power jack 27 and an indicator light 26 located on the other lateral side of the body 29 . The power jack 27 is configured subject to the specification of the power jack 11 of the intelligent cell phone 10 . The indicator light 26 is for visual charging indication.
Referring to FIGS. 4 and 5 , when using the intelligent cell phone 10 with the attachable battery pack 20 , attach the attachable battery pack 20 to the intelligent cell phone 10 by clamping the clamp 21 to one end of the intelligent cell phone 10 and electrically connecting the electrical connector 22 to the power jack 11 of the intelligent cell phone 10 . After connection of the clamp 21 to one end of the intelligent cell phone 10 , the user can bias the body 29 relative to the intelligent cell phone 10 between a close position (see FIGS. 5 and 6 ) where the springy hook 23 is hooked on the other end of the intelligent cell phone 10 and the body 29 is covered on the screen of the intelligent cell phone 10 and an open position (see FIG. 4 ) where the springy hook 23 is disengaged from the intelligent cell phone 10 for enabling the user to operate the intelligent cell phone 10 .
Further, the user can switch on/off the power switch 25 . When the power switch 25 is in the “ON” position, the built-in rechargeable battery of the intelligent cell phone 10 is charged with the attachable battery pack 20 or an external power source that is electrically connected to the power jack 27 , and at the same time the indicator light 26 is turned on to give a visual indication signal. When the power switch 25 is in the “OFF” position, the attachable battery pack 20 is electrically disconnected from the intelligent cell phone 10 .
Further, the user can use the mating charging cable (or battery charger) of the intelligent cell phone 10 and electrically connect the mating charging cable (or battery charger) to the power jack 27 of the body 29 to charge the Li-polymer battery cell of the body 29 of the attachable battery pack 20 with AC power supply (city power supply). During charging, the indicator light 26 is turned on to give a visual indication signal.
Further, it is to be understood that the attachable battery pack 20 can be selectively configured to fit the length, width and thickness of any of a variety of commercial intelligent cell phones.
Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.
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An attachable battery pack having a battery body with a pivoted clamp for detachably fastening to one end of an intelligent cell phone (iPhone or Google phone) as a spare battery. The battery body is configured to overlay the display screen of the intelligent cell phone to provide protection for the display screen and includes a charging circuit and connector for charging the built-in battery of the intelligent cell phone.
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BACKGROUND OF THE INVENTION
The present invention concerns a device for retaining a glass fenestration composed of separate glass structural-section components, especially glass U-section components, or of other longitudinal, especially insulating, glass components. The invention also concerns a retaining rail that can be employed in such a retaining device.
Glass fenestrations composed of longitudinal glass components, glass structural-section components for example, are often employed for the large-area glazing of such buildings as gymnasiums, factories, free-standing staircases, houses, and commercial structures. The fenestrations are often secured by metal structural section in the opening that is to be fenestrated. Especially when a fenestration is insulating, as in the case of a hollow glass structural-section brick for example, water will at the current state of the art occasionally condense inside it and be almost impossible to remove.
SUMMARY OF THE INVENTION
The object of the present invention is to effectively prevent such condensation within a glass fenestration.
The device for retaining a glass fenestration composed of separate glass structural-section components, especially glass U-section components, or of other longitudinal, especially insulating, glass components is accordingly characterized by at least one retaining rail for retaining and bearing and for the lateral guidance and support of the individual longitudinal glass component, glass structural-section component, or glass fenestration, whereby the retaining rail is provided on the one hand with a retaining length of structural section of metal for retaining or supporting a face-side area or part of a face side area of the glass fenestration or one, more, or all of its glass components or glass structural-section components and on the other hand with at least one length of metal flange for the lateral guidance and support of the glass fenestration and/or of one, more or all of its individual glass components or glass structural-section components. Since the length of flange and the retaining section are fastened together by a heat-insulating and/or thermally separating connecting fixture, not only will a reliable bearing or retaining of the glass fenestration be ensured, but the lengths themselves, which are to individually retained, will be thermally separated. The face side areas, which the retaining rails comprise, will not be subject to the undesirable climatological effects of heat bridge-over. Surprisingly, this feature will in turn not only effectively prevent the accumulation of condensed water inside the glass fenestration and the penetration of water thereinto, but the retaining rail will also contribute to the fenestration's insulating effect due to the absence of heat bridging at its retainer.
Advantageous embodiments of the present invention are addressed in the subsidiary claims.
Glass fenestrations of glass structural-section components, especially glass U-section components, are known from Europe Patent 0742324A1, which specific reference will be made to in its entirety for further details as to the design of glass fenestrations. The glass structural U-section components of the glass fenestration known therefrom, however, are to be oriented vertical rather than horizontal. There are accordingly no problems with statics or with installation in a building. Problems do occur, however, when glass structural-section components are to be installed horizontal in that the lowermost component must support the weight of the ones above it.
A retaining device of the aforesaid genus is accordingly of advantage in horizontal glass fenestrations of horizontal glass structural-section components to secure each glass structural-section component individually and ensure that the lower components will need to support no more weight than the upper components do.
Another retaining device for retaining glass structural-components is known from German 29809177 U1, FIG. 4 . This device features horizontal retainers mounted against a wall on bases. This device is accordingly appropriate only for fastening cladding in the form of glass structural-section components, components with L-shaped cross-sections, that is, to a wall, and not for retaining a glass fenestration in an opening in a building.
To ensure that the retaining device in accordance with the present invention provides simple means of securing the glass structural-section components at any desired height when fenestrating an opening in a building, the retaining device in one preferred embodiment is composed of glass structural-section components, especially glass U-section components, to be installed horizontal, whereby at least one retaining rail is installed vertical and designed to secure by tension and/or compression the glass structural-section component s that the glass structural-section components are retained by or rest against. This embodiment features a retaining section for securing by tension and/or compression, especially by way of hammerhead screws or of similar threaded fasteners, a metal structural-section securing section and at least one metal flat section for the lateral guidance or support of the glass structural-section components and/or the glass fenestration. The flat section and the securing section are fastened together by way of the heat-insulating and/or thermally separating connecting fixture.
The vertical and appropriately cross-sectioned retaining rail allows the height of the glass structural-section component holder to be continuously varied. The same retaining device can accordingly retain various glass fenestrations with glass structural-section components of different heights. It is also possible to construct the particular glass fenestration being retained out of glass structural-section components of different widths, of different heights, that is, as installed. The securing section and the flange section are metal for reasons of appearance and/or stability. In particular when closing off openings in a building and in the case of parallel spaces created by glass structural-section components, such metal rails could lead to misting up of the glass structural-section components due to the condensation of water on the inner surfaces of the components. It has, surprisingly, been demonstrated that fabricating the metal sections and thermally insulating them will at least extensively eliminate such misting. Thermal insulation will also of course lead to better k's in the glass fenestration retained by the retaining device.
Further advantageous embodiments of the present invention are addressed in the subsidiary claims. A retaining rail for use in a retaining device in accordance with the present invention is the subject of the ancillary claim.
Since the connecting fixture is intended for thermally separating the securing section from the flange section, all metal heat bridging should be avoided. The connecting fixture should accordingly be of a poorly heat-conducting material. The retaining section or securing section must on the other hand be able to withstand to some extent considerable forces, necessitating a very strong connecting between the flange section and the retaining or securing section. The connecting fixture in one advantageous embodiment of the present invention accordingly comprises a double or triple web or at least two connecting webs of a poorly heat-conducting material, especially plastics-based, extending along the length of the retaining rail and separated from each other at a right angle to that length. The connecting fixture and preferably the double web or connecting webs will also preferably be of polyamide or with a core of polyamide. The advantage of polyamide is that it can be coated subsequently along with the metal sections in accordance with the desired surface of the overall retaining rail. The retaining rail, comprising the retaining section and at least one and preferably two flange sections can accordingly be fabricated and subsequently coated in accordance with the desired appearance of the visible areas. The flange section and/or the retaining section, the aforesaid securing section for instance, will in this event be aluminum.
The retaining section can be of tubing or of another type of structural section reinforced by two walls. When the retaining section is a securing section it will preferably be of C section to allow the head of a threaded fastener to easily engage its back. It will be of advantage when employing tensioning for security to employ heads that can be appropriately oriented for insertion through the gap in the C and rotated 90° to engage the section.
To guide both sides of the glass structural-section component and/or the glass fenestration, comprising for example two lengths of glass structural section with their webs together, composed thereof, and in particular to retain it in the building opening that is to be fenestrated, one preferred embodiment includes two flange sections that extend along both sides of the retaining section, each connected to it by a connecting fixture.
To fasten the metal sections of the retaining rail securely together, it will also be preferable for the connection between the connecting fixture and the particular metal section to be established by engagement of the other side of the hooked edge of an accommodating groove in one of the components involved in the connection by an appropriately cross-sectioned head or end on the other component. It will be preferable in this case for every connecting web in the ends facing the metal section to be more or less T-shaped or otherwise thicker to provide rear engagement for an appropriate C-sectional accommodating groove for each connecting web in the section being connected.
It will also be preferable for the embodiment of the retaining device in accordance with the present invention employed for horizontal glass fenestrations to provide at least one glass structural-section component holder for each glass structural-section component or pair of glass structural-section components to be secured. It will be preferable to provide a retaining device at both vertical edges of the building opening being fenestrated, so that each horizontal glass structural-section component can rest on a glass structural-section component holder at each end. Glass structural-section component holders for retaining the ends of glass structural-section components can preferably be tensioned and hence secured at any desired height by means of at least one threaded fastener, especially a hammerhead screw, each on the C cross-sectional securing section.
It may, now, happen that glass fenestrations of different thickness must be installed in accordance with the on-site situation. It has until now always been necessary to fabricate special structural section, which is really expensive. Retaining devices for particularly thick glass fenestrations, like TWD (transparent heat-insulated glass fenestration) fenestrations are because of their special fabrication, really expensive to manufacture. This problem is eliminated in accordance with a particularly advantageous embodiment of the retaining device in accordance with the present invention. In this advantageous embodiment of the present invention, the retaining device is adjusted to glass fenestrations of different thickness not by fabricating special structural section but by using longer or shorter connecting fixtures. The connecting fixtures are again as hereintofore specified preferably based on plastics and are readily available in various lengths. Depending on whether a shorter connecting fixture or a somewhat longer connecting fixture is employed to connect the flange section to the retaining section, the distance between these two sections will be longer or shorter. Flange, retaining, or securing sections of metal structural section can always be fabricated equal and stocked by the manufacturer. Depending on the builder's specific requirements or on the particular glass fenestration to be retained, the appropriate metal structural sections, i.e. retaining sections and flange sections, can be fastened together by connecting fixtures of appropriate length, e.g. longer or shorter double webs or multiple connecting webs. This particularly advantageous embodiment of the present invention accordingly ensures that the width of the retaining section will match the thickness of the glass fenestration being retained and that at least one matching connecting fixture can be selected from several of varying length.
Another particularly preferred embodiment of the present invention features a set of several retaining rails comprising an essentially U cross-sectional retaining rail designed for strictly lateral support with rectangular structural section as a retaining area adjacent to the face areas of the glass fenestration but with no supporting function, a T-sectional, H-sectional, or I-sectional retaining rail as a middle strut in a glass fenestration or to separate two glass fenestrations, and a lower, retaining rail that is provided on its lower surface, the surface facing away from the building's fenestration, with supporting components. These supporting components are themselves preferably supporting strips, of either simple straight section, I-sectional, or extending out in the form of vertical webs, that is, L-sectional, or T-sectional.
The retaining rail in accordance with the present invention, which is designed for use in a retaining device of the species hereintofore specified, is particularly characterized by a polygonally cross-sectional or, for the tensioned securing of glass structural-section component holders by means of hammerhead screws, C-sectional, retaining or securing section of metal, by at least one projecting flange of metal for the lateral guidance or support of glass structural-section components and/or the glass fenestration composed thereof on the side facing the glass fenestration that the glass structural-section component holder can optionally be applied to, and by a connecting fixture preferably comprising a double web or at least two connecting webs that fasten the two metal sections together thermally separate.
BRIEF DESCRIPTION OF THE DRAWINGS
Various embodiments of the present invention will now be specified with reference to the accompanying drawing, wherein
FIG. 1 is a horizontal section through a retaining rail in a retaining device for retaining glass fenestrations composed of horizontal glass structural-section components,
FIG. 2 is a frontal view of a glass fenestration retained by such a retaining device for closing an opening in a building,
FIG. 3 is a view from the right side of FIG. 1 of an area of the retaining rail in FIG. 1 with a length of glass structural U section retained therein,
FIG. 4 is an overhead view of a securing section in a retaining rail comparable to the one in FIG. 1 with a glass structural-section component holder secured therein,
FIG. 5 is a sectional view along the line V—V in FIG. 4,
FIG. 6 is a view from the right side of FIG. 1 of an area of the retaining rail with an area of the glass fenestration retained therein comparable to the one in FIG. 2,
FIG. 7 is a cross-section through another embodiment of a retaining device for glass fenestrations with three horizontal retaining rails,
FIG. 8 is a view similar to that in FIG. 7 of a third embodiment of a retaining device with three retaining rails or lengths of retaining structural section that differs from the embodiment illustrated in FIG. 7 in width an with respect to a lower retaining rail,
FIG. 9 is a cross-section similar to the ones illustrated in the previous two figures of a fourth embodiment of a retaining device with a retaining rail that again differs in width and wherein the lower retaining rail is further modified, and
FIGS. 10 and 11 are cross-sectional views of two further embodiments of lower retaining rails comparable to the lower retaining rails illustrated in FIGS. 7 through 9 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is a horizontal section through part of a retaining device 1 for a glass building fenestration in the form of a retaining rail 2 . Retaining rail 2 has more or less in the middle a retaining section, a length of C section, in the form of a securing section 3 and two lateral flange sections 4 and 5 . Each flange section 4 and 5 is fastened to securing section 3 by a connecting fixture 6 and 7 respectively. The retaining rail 2 as a whole, with flange sections 4 and 5 , connecting fixtures 6 and 7 , and securing section 3 , is in the form of a length of structural U section, with flange sections 4 and 5 constituting the flanges and connecting fixtures 6 and 7 and, between them, securing section 3 the web. The groove 8 constituted by the inside of C-shaped securing section 3 opens into the inside of the U-sectional retaining rail 2 . The edges of flange sections 4 and 5 are in the same plane as the back 9 of retaining rail 2 opposite the flanges of the U section in retaining rail 2 .
Each connecting area 10 is provided with two C-shaped marginate accommodating grooves 11 . The sides of securing section 3 facing flange sections 4 and 5 are provided with matching connecting areas 12 .
Each connecting fixture 6 and 7 is provided with a multiple web in the form of two connecting webs 13 and 14 (whereof, although the situation is not illustrated, there may be more than two). Each connecting web 13 and 14 is in the form of a length of I section, the flanges of the I being, to ensure precise fit in accommodating grooves 11 , located at the terminating sections 15 facing the sections 3 through 5 being secured. The accommodation of I-shaped terminating sections 15 in grooves 11 provides connecting fixtures 6 and 7 with a solid attachment to both flange sections 4 and 5 and securing section 3 . To further improve stability, the accommodating grooves 11 in each connecting area 10 and 12 , and hence the connecting webs 13 and 14 accommodated therein, are a specific distance apart. Securing section 3 and flange sections 4 and 5 are metal, aluminum in the preferred embodiment illustrated. Connecting webs 13 and 14 are polyamide. The retaining rail 2 in some unillustrated embodiments is coated with plastic, powder, or a similar material.
The free end of each flange section 4 and 5 is provided with a hook-shaped structure 16 incorporating an inside groove 17 facing the interior of the U section that comprises the retaining rail.
The purpose of retaining rail 2 will now be specified with reference to FIGS. 2 through 6.
FIG. 2 is a frontal view of part of a wall 19 surrounding an unobstructed opening 18 in a structure, a building for example. Opening 18 is fenestrated by a glass fenestration 20 . Glass fenestration 20 is composed of several longitudinal and horizontally disposed glass U-section components 21 .
Since the longer glass structural-section components 21 are, the more considerable they can weigh, to eliminate rateable loads on the components, accordingly, they are retained at their ends in retaining rails 2 secured to the vertical soffit areas of opening 18 . Since it is the retaining of an individual glass structural-section component 21 that is the object, it rests, as illustrated by way of example in FIG. 3, on a glass structural-section component holder 22 with the component's end accommodated in retaining rail 2 and supported at the side by a flange section 5 . A sealing component 23 acts as a cushion between flange section 5 and glass structural-section component 21 . Glass structural-section component holder 22 is retained against securing section 3 by a threaded fastener 24 provided with a lock nut. The head 27 of threaded fastener 24 engages the back of the edge of groove 8 . The situation will now be specified with reference to FIGS. 4 and 5.
The threaded fastener 24 in the embodiment illustrated therein comprises a hammerhead screw 25 with matching nuts 26 that tension and secure screw 25 in groove 8 with head 27 at any desired height ( 28 ).
The glass structural-section component holder 22 is angled and has a supporting surface 29 for a single glass structural-section component 21 .
FIG. 6 illustrates another embodiment wherein a glass fenestration 20 composed of several interlocking glass structural-section components 21 and 21 ′ each with its flanges facing those of the others can be retained at its individual components. The glass structural-section component holder 22 ′ in this embodiment is essentially F-shaped in cross-section, whereby the resulting two supporting surfaces 29 each serve for bearing the upper flange of two mutually facing glass structural-section components 21 and 21 ′. The outward-facing webs of glass structural-section components 21 and 21 ′ are both retained by flange sections 4 and 5 , whereby here again sealing components 23 acting as cushions are accommodated in inside grooves 17 . Although appropriate seals 30 are provided between the horizontally aligned glass structural-section components 21 and 21 ′ sealing the hollow interior space 31 between them and preventing water vapor from escaping, the resulting double-walled glass fenestration is, in spite of its secure bearing in securing section 3 and the accordingly dictated thermal coupling thereto, very insensitive to misting up or condensed-water accumulation inside. The reason for this is that the connecting fixtures 6 and 7 constituted by connecting webs 13 and 14 ensure thermal uncoupling between the flange sections 4 and 5 that represent the wall of retaining device 1 and securing section 3 .
Various aspects of the first embodiment of the retaining device hereintofore specified and of the retaining rail accommodated therein will now be summarized with reference to FIG. 1 .
To provide a simple-to-produce and universally employable retainer for retaining a glass fenestration 20 comprising in particular horizontal glass structural-section components, specifically glass U-section components 21 and 21 ′, whereby misting up of the glass structural-section components from inside will be impossible, a retaining device 1 is proposed with at least one vertical retaining rail 2 for the tensioned or compressed attachment of the glass structural-section component holders 22 and 22 ′, on or by which the glass structural-section components 21 and 21 ′ are retained or borne, whereby the retaining rail 2 features a projecting flange section 4 or 5 for the tensioned or compressed, especially by means of hammerhead screws 25 or similar threaded fasteners 24 , attachment of a structural-section••sectional securing section 3 in the form of a retaining section and at least one flange section 4 for the lateral guidance or support of glass structural-section components 21 and 21 ′ and/or glass fenestration 20 . The flange section 4 or 5 and the retaining or securing section 3 are metal and are fastened together thermally separated from each other by a connecting fixture 6 or 8 .
FIGS. 7 through 11 illustrate further retaining rails for retaining devices 35 , 66 , and 73 for glass fenestrations. These embodiments mainly include horizontal retaining rails that can easily be employed along with the laterally vertical retaining rails 2 in the first embodiment. The retaining rails illustrated in FIGS. 7 through 11, however, are also appropriate for retaining and supporting vertically mounted longitudinal glass components or glass structural-section components and glass fenestrations composed thereof. Further embodiments of the retaining device accordingly feature retaining rails of the species illustrated in FIGS. 7 through 11 along with for example, instead of the vertical retaining rails illustrated in FIG. 1, lateral retaining rails of the form illustrated as upper retaining rails 32 , 33 , and 34 in FIGS. 7, 8 , and 9 .
The second embodiment of a retaining device 35 , the horizontal retaining rails 32 , 36 , and 37 whereof are illustrated in cross-section in FIG. 7, features an upper retaining rail 32 , a middle retaining rail 36 , and a lower retaining rail 37 .
Upper retaining rail 32 is essentially similar to retaining rail 2 except that the securing section 3 employed as a retaining section 38 in retaining rail 2 is not C-sectional, the side facing the glass fenestration being continuous and without a gap. Retaining section 38 is accordingly on the whole essentially rectangular in cross-section, the side facing the glass fenestration being provided with a supporting surface 39 that can retain or support an unillustrated matching face-side area of the glass fenestration. The connecting fixtures 40 and 41 are comparable to connecting fixtures 6 and 7 although of different length, the distances A 1 and A 2 between flange section 5 and retaining section 38 or retaining rail 36 differ, in contrast to those apparent from FIG. 1 . The connecting fixtures 40 , 41 , 6 , 7 (FIG. 1 ), 8 , or 40 and 44 (FIG. 9) 45 and 46 , or 47 and 48 (FIGS. 10 and 11) accordingly allow the thicknesses B 1 , B 2 , B 3 , B 4 , and B 5 between the individual flange sections to be adjusted to the particular glass fenestration or other structural conditions employed.
In order to accommodate glass fenestrations with particularly large faces, the flange sections 4 ′ and 5 ′ in upper retaining rail 32 are L-shaped, the shorter L-shaped web 4 a ′ being rectangular and provided with connecting areas 10 . Upper retaining rail 32 for example can be employed either as an upper guide for retaining the glass fenestration's upper face-side area inside the building opening (retaining section 38 taking no part in the support) or as lateral guides similar to the retaining rails 2 in FIG. 2 although applicable to vertical glass structural-section component glass fenestrations.
The middle retaining rail 36 in the illustrated embodiment is essentially H-shaped or I-shaped and features, in addition to the essentially rectangular cross-sectional retaining section 38 , I-shaped cross-sectional flange sections 49 and 50 , which are fastened to retaining section 38 by means of connecting fixtures 41 and 40 . The I-shaped cross-section of flange sections 49 and 50 derives from the shape of flange sections 4 ′ and 5 ′ in that another flange 51 extends opposite flange 52 . A rectangular cross-sectional and hence stronger web 53 extends halfway between flanges 51 and 52 with connecting area 10 at its free end.
Lower retaining rail 37 also features a retaining section 54 and two flange sections 57 and 58 secured to it by connecting fixtures 55 and 56 that are similar, with the exception of the distance between connecting webs 13 and 14 , to connecting fixtures 41 and 40 . Retaining section 54 has a rectangular cross-sectional section 54 a with connecting areas 12 and supporting components 59 . The supporting components 49 [sic] in lower retaining rail 37 consist of supporting strips 60 in the shape of upside-down T's.
Flange sections 57 and 58 are provided with an outward-bent flange 61 that extends around the lower face-side area of the glass fenestration and with a supporting wall 62 that is also provided at its free lower end with supporting components 59 in the form of supporting strips 60 . Supporting wall 62 is provided on the side facing retaining section 54 with a connecting area 10 . On the opposite side, supporting wall 62 is provided with a more or less hook-shaped strip 63 for anchoring etc.
The upper, middle, and lower retaining rails 33 , 64 , and 65 in the third embodiment of a retaining device 66 illustrated in FIG. 8 differ from the retaining rails 32 , 36 , and 37 illustrated in FIG. 7 in the length of connecting fixtures 6 and 7 . This embodiment is accordingly provided with additional connecting fixtures 67 and 68 . Connecting fixtures 67 and 68 differ from the connecting fixtures 55 and 56 in the second embodiment in that they have the same length A 3 as connecting fixtures 6 and 7 . Flange sections 4 ′ and 5 ′ and 49 and 50 and the retaining sections 38 in upper retaining rail 33 and middle retaining rail 64 illustrated in FIG. 8 are similar to upper and middle rails 32 and 36 in the retaining device 35 illustrated in FIG. 7 . Lower retaining rail 65 also corresponds essentially, except with respect to its supporting components 59 , to the lower retaining rail 37 illustrated in FIG. 7 . Thus, retaining section 69 is provided on its lower side with a supporting component 59 in the middle in the form of a web 70 that extends straight down. Flange sections 71 and 72 have supporting components in the form of L cross-sectional supporting strips, although they are otherwise similar to flange sections 58 and 57 .
The fourth embodiment of a retaining device 73 , illustrated in FIG. 9, is also mainly similar to the hereintofore specified embodiments 35 and 66 , although its connecting fixtures 43 & 44 and 74 & 75 , the last on lower retaining rail 76 , differ in length. The supporting components 59 in both the flange sections 71 and 72 of lower retaining rail 76 and of the retaining section 77 in lower retaining rail 76 are in the form of L cross-sectional supporting strips 78 . FIGS. 10 and 11 illustrate further embodiments of lower retaining rails 79 and 80 to be employed with glass fenestrations of shorter thicknesses B 4 and B 5 in building openings with more massive walls. Flange sections 81 and 82 , in contrast to those in the hereintofore specified embodiments, are not entirely symmetrical. One flange section 81 features, in addition to a flange 83 that extends out at an angle and is in turn provided with a downward-extending strip 84 , a windowsill area that extends out from supporting wall 62 . The supporting component 59 in this flange section 81 is an almost U cross-sectional supporting strip 86 . Flange section 82 features, in addition to a flange 87 that also extends out at an angle and to a supporting wall 62 , a supporting component 59 in the form of an L-shaped supporting strip 78 . The retaining sections 87 and 88 illustrated in FIGS. 10 and 11 on the other hand are different. Although retaining sections 87 and 88 are indeed essentially also rectangular in cross-section like the retaining sections 54 , 69 , and 77 in the embodiments illustrated in FIGS. 7 through 9, they are in this case higher than they are wide, allowing them to function with lesser thicknesses B 4 and B 5 . Different thicknesses can also be further compensated by means of connecting fixtures 46 through 48 of different length. In this event, the retaining section 87 illustrated in FIG. 10 is even wider than the retaining section 88 in FIG. 11 . Because of the in this case shorter distance that must be spanned between supporting components 69 and flange sections 81 and 82 , there is no need for any supporting components 59 on retaining sections 87 and 88 . Embodiments similar to those in FIGS. 10 and 11 but employing retaining sections with supporting components are of course also conceivable.
Whereas the connecting fixtures 47 and 48 illustrated in FIG. 11 consist, like those in the hereintofore specified embodiments, of two straight connecting webs 13 and 14 , the connecting webs 89 and 90 in the connecting fixtures 45 and 46 illustrated in FIG. 10 differ essentially from connecting webs 13 and 14 . Upper connecting fixture 89 is, in order to enlarge the supporting surface 39 for the face side of the glass fenestration, either displaced upward at an angle or cropped, whereas lower connecting web 90 features not only a thicker T-shaped head for engaging the back of accommodating groove 11 but grooves in a thicker head 91 or end.
Further embodiments of retaining devices in accordance with the present invention can be obtained by combining the features described with reference to FIGS. 1 through 11 as desired.
List of Parts
1 . retaining device
2 . retaining rail
3 . securing section (retaining section)
4 . flange section
4 ′. L-shaped flat section
4 a ′. reinforced short web
5 . flange section
5 ′. L-shaped length of flange
6 . connecting fixture
7 . connecting fixture
8 . groove
9 . back
10 . connecting area
11 . accommodating groove
12 . connecting area
13 . connecting web
14 . connecting web
15 . terminating section
16 . hook-shaped structure
17 . inside groove
18 . opening
19 . wall
20 . glass fenestration
21 . glass structural-section component
22 , 22 ′. glass structural-section component holder
23 . sealing component
24 . threaded fastener
25 . hammerhead screw
26 . nuts
27 . head
28 . adjustable height
29 . supporting surface
30 . seals
31 . Interior space
32 . upper retaining rail
33 . upper retaining rail
34 . upper retaining rail
35 . retaining device, second embodiment
36 . middle retaining rail
37 . lower retaining rail
38 . retaining section
39 . supporting surface
40 . connecting fixture
41 . connecting fixture
42 . connecting fixture
43 . connecting fixture
44 . connecting fixture
45 . connecting fixture
46 . connecting fixture
47 . connecting fixture
48 . connecting fixture
49 . T-shaped flange section
50 . T-shaped flange section
51 . additional second flange
52 . first flange
53 . web
54 . retaining section
55 . connecting fixture
56 . connecting fixture
57 . flange section
58 . flange section
59 . supporting component
60 . supporting strip
61 . angled flange
62 . supporting wall
63 . hook-shaped strip
64 . middle retaining rail
64 ′. middle retaining rail (fourth embodiment)
65 . lower retaining rail
66 . retaining device, third embodiment
67 . connecting fixture
68 . connecting fixture
69 . retaining section
70 . web
71 . flange section
72 . flange section
73 . retaining device, fourth embodiment
74 . connecting fixture
75 . connecting fixture
76 . lower retaining rail
77 . retaining section
78 . L-shaped supporting strip
79 . lower retaining rail
80 . lower retaining rail
81 . flange section
82 . flange section
83 . angularly projecting flange
84 . strip
85 . windowsill area
86 . more or less U cross-sectional supporting strip
87 . retaining section
88 . retaining section
89 . connecting web
90 . connecting web
91 . thicker head
A 1 -A 7 . differing distances
B 1 -B 5 . differing inside thicknesses
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The invention relates to a holding device for holding glass closures ( 20 ) formed by individual glass profile elements, especially U-shaped glass profile elements ( 21, 21′ ), or other long glass elements, especially insulating glass elements. In order to prevent water condensation inside the glass closure ( 20 ), the holding device comprises at least one holding rail ( 2; 32, 36, 37; 34, 64, 65; 34, 64′, 76; 79; 80 ) for holding or mounting and for laterally guiding and supporting the individual long glass elements or glass profile elements ( 21, 21′ ) or the glass closure ( 20 ). Said holding rail ( 2; 32, 36, 37; 34, 64, 65; 34, 64′, 76; 79; 80 ) has a metal holding segment ( 3; 38; 54; 69, 77; 87; 88 ) for holding or supporting a front face area or a partial front face area of the glass closure ( 20 ) or individual glass elements or glass profile elements ( 21, 21′ ) at least one projecting metal flange section ( 4, 5; 4′, 5′; 49, 50; 57, 58; 71, 72; 81, 82 ) for laterally guiding or supporting the glass closure ( 20 ) and/or one, several or all the individual glass elements or glass profile elements ( 21, 21′ ) thereof, whereby the flange segment ( 4, 5; 4′, 5′; 49, 50; 57, 58; 71, 72; 81, 82 ) and the holding segment ( 3; 38; 54; 69, 77; 87; 88 ) are fixedly connected to one another by means of a heat-insulating and/or thermally separating connecting device ( 6, 7; 40, 41; 43, 44; 45, 46, 47, 48; 67, 68; 64, 65 ). The invention also relates to a holding rail that can be used in said holding device.
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