System and method of processing and packing disk-like objects

A system for automatically forming several parallel rows of disk-like objects on a conveyor into stacks and packing those stacks into boxes is disclosed along with a method of operating the system. The system includes a stacker receiving the disk-like objects as they fall of the conveyor, a buffer receiving stacks from the stacker in groups of a first number, a transfer device for removing the stacks from the buffer in groups of a second number, and a packer for packing the stacks into boxes. The second number can be less than, greater than, or equal to the first number.

FIELD OF THE INVENTION

This application is directed to a system and method for processing and packing disk-like objects, and, more specifically, toward a system and method for forming multiple stacks of disk-like objects, arranging the stacks in a matrix of rows and columns, and packing the stacks thus arranged in a container.

BACKGROUND OF THE INVENTION

Machines for processing hamburger patties, chicken patties, sausage patties, and similar disk-like objects are known and often include a conveyor belt or similar mechanism for moving the patties into and out of a freezer, moving the patties beyond a metal detector to check for contamination, and otherwise supporting the patties while they are processed. However, in order to package the patties, they generally must be removed from the conveyor and stacked, and the stacks must then be placed into the boxes, cartons, or other containers. Heretofore, various machines have been proposed for performing some or all of the packing functions. For example, stacking machines such as the one shown in U.S. Pat. No. 6,052,969, assigned to the assignee of the present application, form hamburger patties into stacks as they exit a conveyor.

One reason that manual labor has heretofore been required is that the number of rows of patties on a conveyor belt is not always the same as the number of rows that will be placed in a container. For example, the number of rows of hamburger patties on a conveyor is generally related to the width of the conveyor. Processing multiple rows simultaneously increases efficiency. However, this number is sometimes greater than the number of rows that will fit into a case or box, so the rows must somehow be consolidated before they are boxed. In the past, this has been done by having laborers take individual stacks as they were formed and manually placing the stacks in a box.

Moreover, even when individual machines exist that either stack or pack objects such as hamburger patties, they are not always easily integratable and do not function as a system. For example, if one element of the system works more slowly than other elements, a bottleneck will develop and reduce system throughput. There is therefore a need for a system that can receive substantially any number of rows of disk-like objects from a conveyor, form the objects into stacks, and place appropriate numbers of these stacks into rows and columns in a box.

SUMMARY OF THE INVENTION

These and other difficulties are addressed by the present invention which comprises an integrated system for receiving moving multiple rows of frozen hamburger patties along a conveyor belt, forming the patties into stacks, and packing the stacks into boxes at a rate at least as great as the rate at which the patties are presented by the conveyor. The subject invention finds particular utility in connection with the packaging of frozen hamburger patties; however, it could just as easily be used to package other food products or flat, non-food objects. The invention is described herein in connection with the processing of frozen hamburger patties, but is in no manner limited to use with such products.

A first portion of the subject system includes a conveyor that moves frozen patties toward a stacking device which receives the patties as they fall from the end of a conveyor belt and forms the patties into stacks. In a preferred embodiment, the stacker includes a first holder, sometimes referred to as an upper holder or upper shelf, onto which the rows of patties fall as they reach the end of the conveyor. The upper holder preferably comprises a plurality of pairs of parallel pins that extend from a support toward the end edge of the conveyor so that individual patties in a given row drop one at a time off the end of the conveyor onto a pair of pins. Hereafter, the processing of a single stack of patties will sometimes be discussed, it being understood that second and additional stacks are being formed substantially simultaneously on adjacent pairs of pins. The upper holder is lowered as each new patty falls, to keep the top of the stack about the same distance beneath the end edge of the conveyor. The height of the top of the stack varies somewhat during processing, but it is preferably maintained within a fairly narrow range of heights to ensure that the patties drop consistently onto the stacks. In the preferred embodiment, a counter adjacent the conveyor counts patties in a row just before they fall onto the upper support, and a cam lowers the upper support at a known rate.

A second holder comprising a plurality of fingers is positioned beneath the upper support, with each finger aligned with the opening between a pair of upper support pins. As the upper support drops, the pins eventually pass to each side of one of the fingers, and as the upper support drops further, the bottom of the stack contacts a finger on the second holder and is supported thereby. When the stack is completely supported by the fingers, the upper support pivots away from the stream of falling patties and returns to its starting position while the second holder continues to drop, keeping the top of the stack at a generally constant height. A transfer device is mounted beneath the second support, which device includes a plurality of openings aligned with each of the fingers on the second support. When a stack contains the correct number of patties, or is otherwise determined to be complete, the second holder drops so that the fingers pass through the openings in the transfer device, leaving the stacks supported by the transfer device. Preferably, as soon as the second shelf begins to drop, the first shelf rises and pivots back to its starting position to catch the falling patties, while the end of the conveyor is moved to lengthen the conveyor and create a gap in the flow of patties; this delays the release of the next group of patties and allows the upper shelf to move into position to catch additional patties. The upper support thus supports a next group of falling patties, while the following processing steps are carried out on the first stack.

Once the stacks are supported on the transfer device and the fingers of the second holder are located beneath the transfer device, the transfer device grips the stacks and moves sideways to transfer the stacks to a buffer. As the transfer device is moving the stacks to the buffer, the second holder is free to return to its starting position beneath the top shelf. Once the transfer of patties to the buffer is complete, the transfer device returns to its starting location beneath the second holder, and the process is repeated.

A second portion of the system is a buffer which receives a first number of stacks from the stacker. In a preferred embodiment, the buffer comprises a carousel to which a plurality of carriers are attached, each carrier holding a tray that receives a single stack of frozen hamburger patties. Each carrier is attached by a clamp to a belt that runs continuously around the carousel, the clamp engaging the belt on opposites sides thereof. The clamp is attached tightly enough to cause the carrier to move with the belt when its path is unobstructed, but loosely enough that the belt will slide through the clamp when the path of the carrier is blocked. In this manner, the position of the carriers can be controlled independently of the positions of the other carriers, without a need to provide separate controllers for the clamps on each carrier.

The movement of the carriers is controlled so that a first number of trays is always available when needed to receive a first number of incoming stacks, and, when full, the carriers are released to a second location where they are stopped so that stacks of patties can be removed therefrom by a transfer device in groups of a second number. When the second number is less than the first number, the stacks must be removed at a rate greater than the rate at which the stacks of patties arrive at the carousel, and full carriers are buffered at a location between the first and second locations. When the second number is greater than the first number, full carriers are accumulated at the second location until a second number of carriers is present. When the first and second numbers are the same, the carriers move around the carousel in equal size groups.

In the preferred embodiment, the number of carriers is related to the maximum number of incoming rows of patties, to minimize the number of carriers needed, and thus reduce the amount of space occupied by the machine. Applicants have found, for example, that a stacking machine that produces four rows of patties used with and a packaging machine that requires three rows at a time as input, a buffer having a total of eleven carriers is needed. In this manner, the width of the buffer can be minimized and the resulting buffer need not be much greater than the width of the stacking machine.

A third portion of the system comprises a transfer device for removing the stacks of patties from the trays of the buffer device and placing them on a platform from which they can be further processed. In the preferred embodiment, the transfer device comprises a generally rectangular frame having parallel top and bottom members, a plurality of stack supports mounted on the bottom member and a plurality of actuators supporting plates depending from the top member. The actuators cause the plates to move toward and away from the bottom member, and the bottom member is movable relative to the top member via additional actuators. The frame is shiftable between the buffer, where it engages several stacks of patties, and a platform, where the stacks are deposited for further processing. In the preferred embodiment, the stacks at the first location are located in individual trays of the buffer, and are oriented at a small angle to the vertical so that the stacks are supported by both a bottom wall and a side wall of a holder, while the second location comprises a shelf-like member on which the stacks are supported by the lower-most patty in the stack. The frame is pivotable about an axis parallel to the bottom frame member so that it can shift the stacks from a first orientation with respect to vertical to a second generally vertical orientation.

In operation, the frame moves and pivots until it substantially surrounds a plurality of stacks of patties, and so that the support members on the lower frame member are positioned beneath slots in the bottoms of the trays and with the plates located over the tops of each of the stacks. Actuators then move the bottom frame member up against the bottoms of the stacks and move the plates against the tops of the stacks to grip each stack between one bottom frame stack support member and a plate. The frozen patties have relatively rough surfaces, and therefore only a small amount of pressure needs to be applied to hold the stacks securely together while they are being moved. If the objects in the stacks were formed of a low-friction material, a greater force would be required to compress the stacks and keep them together. The frame next pivots about an axis below and parallel to the bottom frame member and moves away from the trays to a second location where the patties are to be deposited.

The second location comprises a matrix former, which receives several stacks of patties and arranges the stacks for placement into a case or other container. The matrix former includes a generally horizontal lower support surface with slots wider than the bottom frame member stack supports but narrower than the width of the stacks, and three upstanding sidewalls extending away from the lower support surface, which side walls are movable relative to the bottom support surface to square the stacks on the lower support surface. The distance between the frame side members is greater than the distance between the matrix former side walls, so the frame surrounds the matrix former as the stacks are deposited thereon. When the bottoms of the stacks are located over the lower support surface of the matrix former, the frame bottom moves away from the stack bottoms through the slots to deposit the stacks on the lower support surface and the plates are also moved away from the top of the stacks. The transfer mechanism then returns to the first location, where another set of stacks has been moved into position for transfer and repeats the above process, but leaves the second group of stacks at a third location between the first location and the second location one patty diameter closer to the first location than the second location.

A fourth portion of the system comprises a packer comprising the matrix former having a first platform on which a plurality of stacks of patties are placed, and a second platform for supporting a box into which the stacks are to be packed. The second platform is movable vertically, and pivots about an axis parallel to its box-contacting surface. The second platform includes at least one gripper for holding the bottom of the box securely against the box-contacting surface, and preferably also includes a plurality of grippers for engaging the top edges of the box to control the movement of the box and to hold down flaps extending from the top edge of the box. The box-contacting surface of the second platform also preferably includes a plurality of rollers that allow an empty box to roll on and off the platform when the platform is inclined.

In operation, the second platform is aligned with a conveyor that feeds empty boxes one at a time to the second platform, where an individual box is gripped by at least one gripper on the second platform to hold it in place with its bottom on the rollers and its open top facing away from the rollers. The second platform is then pivoted about 158 degrees to an inverted position with the open box top positioned over and facing the first platform over the stacks of patties on the first platform. The second platform is next lowered over the stacked patties and over the first platform so that the products and platform are disposed completely within the box. The orientation of the patties is maintained by the walls of the box and the platform, and the first and second platforms are pivoted together until the top opening of the box is again facing up and the patties are supported on the closed bottom of the box. The second platform and box are moved away from the first support, and the first support is returned to its original orientation. The second support is moved to a discharge location to slide the fully loaded box onto a conveyor for further processing and then tilts and moves to its original position to receive another empty box to start the process again.

Thus in operation, multiple rows of hamburger patties drop over the edge of a moving conveyor belt and form a plurality of stacks on a stacker as they fall. When the stacks achieve a predetermined size, they are transferred automatically to a buffer carousel while a second set of stacks is formed on another portion of the stacker. Transfer of stacks from the stacker to the buffer is accomplished without slowing the conveyor or interfering with the upstream processing of the patties. A first number of stacks of patties, four for example, are loaded into four trays of the buffer and moved from a first location to a second location. At the second location, a second number of stacks of patties, three for example, are removed from the trays and moved to the support surface of the matrix former. Additional patties are received four stacks at a time at the first location, and moved to the second location where they are removed three stacks at a time. The stacks on the matrix former are boxed and removed each time a desired number of stacks has been received on the matrix former. Because the stacks may be removed from the buffer at a rate greater than the rate they are placed on the buffer, a constant throughput is achieved, and the flow of patties on the conveyor is substantially matched to the output flow of patties from the boxer. Because the stacks are flipped twice during processing, once between the stacker and the buffer and again when the filled carton is inverted, the stacks end up in a carton in the same orientation as they are in when they are formed on the stacker.

It is therefore a primary object of the present invention to provide an automated system for processing and packing a plurality of disk-like objects such as frozen food patties.

It is another object of the present invention to provide a system for receiving a plurality of rows of disk-like objects from a conveyor, forming the objects into stacks and packaging the stacks thus formed.

It is a further object of the present invention to provide a method for stacking a first number of rows of objects and packing a second number of rows of stacks into a box.

It is yet another object of the present invention to provide an automated system for processing and packing a plurality of disk-like objects, including a stacker for forming a first number of stacks, a packing subsystem that packs stacks into a box in rows of a second number of stacks, and a buffer for converting said first number of stacks into groups of said second number of stacks.

In furtherance of these objects, an apparatus is provided for forming stacks of disk-like objects and packing the stacks in a box that includes a stacker for forming a plurality of stacks of the disk-like objects, a buffer, and a first transfer mechanism for transferring the plurality of stacks from the stacker to the buffer. A second transfer mechanism is also provided for transferring at least some of the stacks on the buffer to a platform, and a boxer is included for boxing the stacks of objects on the platform.

A further aspect of the invention comprises a method for processing a flow of disk-like objects that involves conveying at least two rows of disk-like objects toward and over an edge and providing at least two catchers adjacent the lip. The disk-like objects of each row are caught by the catchers as they fall over the edge thus forming a stack of objects on each of the catchers. A buffer comprises a plurality of stack carriers individually movable around a closed loop, and at least two stacks of objects from the catchers are moved to at least two of the carriers. The two carriers are moved from a first location to a second location. At the second location a number of stacks are removed and placed on a platform to form a first column. Additional stacks are removed from the second location and placed on the platform to form a second column. Finally, a box is placed over the first and second columns of stacks, and inverted together with the stacks, to transfer the stacks from the platform to the box, after which the box is moved away from the platform.

A further aspect of the invention comprises an apparatus for packing disk-like objects and includes a stacker receiving a first number of rows of objects from a conveyor and forming the rows into stacks, a buffer for receiving the stacks in groups of a first number, a packer for packing the stacks in a box, and a transfer mechanism for transferring the stacks from the buffer to the packer in groups of a second number.

Another aspect of the invention is a method of packing disk-like objects that involves moving a first number of rows of disk-like objects along a conveyor toward a conveyor end edge, and providing a first number of catchers in a row adjacent the end edge, each of the catchers being aligned with one of the first number of rows of disks. The disks in each of the rows are caught to form a stack on each of the catchers, after which they are transferred from the catchers to a buffer. From the buffer, the stacks are transferred to a packer in groups of a second number, and automatically packed into a box.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, wherein the showings are for purposes of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting same,FIG. 1shows a hamburger patty processing system1that includes a stacker10, a buffer310, a stack transfer device510and a packing machine810. Each of these elements is described in more detail below.

Stacker

The stacker portion of the subject system is described in an application entitled “Method And Apparatus For Stacking Discrete Planar Objects” filed concurrently herewith and assigned to the assignee of this application.

As best shown inFIGS. 2 and 4, a stacking device10is positioned adjacent a conveyor12having an end edge14. A plurality of disk-shaped objects16, in this case, frozen hamburger patties, are arranged in rows on the conveyor12extending in the direction of movement of the conveyor12. As conveyor12moves, it causes patties16to be advanced so as eventually to drop off end edge14onto an upper support18, as best shown inFIG. 6, to form stacks20of patties thereon as best shown inFIG. 12. Upper support18is downwardly movable in order to keep the top of stacks20at a generally constant level with respect to end edge14of the conveyor12. As upper support18descends, it transfers the accumulating stacks20to a lower support22, as best shown inFIG. 4, and moves laterally out of the falling streams of patties so that further patties16from the conveyor12fall directly onto the stacks20supported by lower support22. The lower support22is downwardly movable and continues to drop until a sensor226detects that the stacks20have reached their final size. At this point, lower support22transfers the stacks20to a stack transfer mechanism24that moves the stacks20laterally away from the conveyor12toward a discharge location. Additional falling patties16are caught by upper support18or lower support22as discussed above, and transfer device24returns to its starting position beneath the upper support18and the conveyor12before a subsequent set of stacks of patties16is complete. Controller23, as best shown inFIG. 2, controls the operation of the stacking device, and is preferably a computer or PLC that controls the speed of various drives and the operation of the actuators that are described herein. The present system allows for a continuous processing of patties16arriving at the end edge14of a conveyor12without the need to stop the conveyor each time a stack is completed.

Stacker10is installed on a fixed support26, such as a factory floor, and includes a fixed frame portion28fixed with respect to support26and a movable frame portion30that moves with respect to the fixed frame portion24, which fixed frame portion28and movable frame portion30together form a frame for the stacker. Movable frame portion30includes four support wheels32resting on four platforms34, which in turn rest on the fixed support26. A motor36is operably connected to a shaft38, which is rotatably supported by two bearings40that are supported by bearing supports42, one of which is shown inFIG. 2, mounted on floor26. Two arms44are fixed to shaft38and extend radially therefrom so that the ends of arms44describe an arc of a circle as the shaft38rotates. Tie rods46connect arms44to movable frame30so that, as motor36turns shaft42in a first direction, the movable frame portion30is pulled along platforms34toward motor36, and as motor36turns in a second direction, the movable frame portion30is pushed along platforms34away from motor36. The roller48supporting the end edge14of the conveyor12(FIG. 4) is supported on the movable frame portion30while other portions of conveyor12are supported by the fixed frame portion28. Therefore, the conveyor12includes a slack take-up mechanism50, shown inFIGS. 10–13, which allows the effective length of the conveyor12to increase and decrease as the movable frame portion30moves away from and back towards the fixed frame portion28. When the effective length of the conveyor12is increased in this manner, the spacing is increased between rows of patties16arriving at end edge14, and this extra spacing allows the upper support18to pivot back into the flow of falling patties to start a new stack.

Movable frame portion30comprises a first vertical plate member52having an inner wall54and an outer wall56, and a second vertical plate member58having an inner wall60and an outer wall62. A guide64is formed on inner wall54of the first vertical plate member52by a pair of spaced rails66, while an upper guide is formed in the second vertical plate58by an upper slot70, and a lower guide is formed in second vertical plate58by a lower slot74. Rods76and77extend between the inner walls of the first and second vertical plates to maintain their spacing.

With reference toFIGS. 4 and 6, upper support18comprises a carrier78including a first side plate80having an inner side82and an arcuate slot84, and a second side plate86having an inner side88, an outer side90and an arcuate slot92aligned with arcuate slot84in the first side plate80. The second side plate86is parallel to the first side plate80and spaced therefrom by connecting rod94. Carrier78supports a pivoting member96comprising a first L-shaped member98having an outer wall100with a pin102(seen inFIG. 4) projecting therefrom and an inner wall104, and a second L-shaped member106having an inner wall108facing inner wall104of the first L-shaped member98and an outer wall110from which a pin112projects. The outer wall100of first L-shaped member98overlies the inner side82of first side plate80, with pin102received in arcuate slot84, and extends beyond the first side plate80. The outer wall110of the second L-shaped member106overlies the inner side88of second side plate86with pin112received in arcuate slot92of the second side plate16. A first rod114extends between the middle portions of the inner walls104,108of the first and second L-shaped members98and106, respectively, and a second rod116extends between the portions of the first and second L-shaped members98and106, respectively, that project beyond the first side plate80and second side plate86. A plurality of pins118arranged in pairs120spaced apart by a given distance extend radially from second rod116as best shown inFIG. 6. First L-shaped member98is pivotally connected to the inner wall82of first side plate80at a pivot point122, while second L-shaped member106is pivotally connected to the inner wall108of the second side plate86at a pivot point124. An actuator126, preferably a pneumatically actuated cylinder, is connected between first side plate80and an end128of first L-shaped member98on the opposite side of pivot point122from rod114, which actuator126causes first L-shaped member98, and hence carrier78, to pivot about pivot points122and124, while pins102and112in arcuate slots84,92guide the movement of the pivoting member96with respect to the carrier78. Guide wheels130are mounted on the outer walls of the first side plate80and second side plate86which wheels are received in the guides64,70of the vertical plates52and58of the movable frame portion30. A cam follower132also extends from the outer side90of the second side plate86. Plates133attached to rod94form a backstop against which patties impact as they form stacks on the pairs120of pins118.

FIG. 7illustrates lower support22, which includes a first side plate134having an inner side136and an outer side138, and a second side plate140having an inner side142and an outer side144. A strut146connects the inner sides of the first and second side plates134and140, respectively, and a hexagonal rod148extends between the inner sides of the first and second plates parallel to strut146. Guide wheels150are attached to outer sides138and144of first side plate134and second side plate140, respectively, and the outer side144of second side plate140further includes a cam follower152. A plurality of fingers154are attached to hexagonal rod148, each of which includes at least one planar surface156.

Transfer mechanism24, best shown inFIGS. 8 and 9, comprises a first L-shaped plate member158and a second plate member160parallel to and spaced from first plate member158by a rod162extending between end portions of plate members158and160which rod162is supported at either end by bearings164. A tray assembly166includes two side plates168connected by a connecting rod170. A plurality of trays172, each having a bottom wall174having a slot176and side walls178, are pivotally attached to plate members158,160. A hexagonal rod180is rotatably attached between side plates168, and a plurality of L-shaped covering fingers182are attached thereto. Actuator184, connected between the plate member158and hexagonal rod180, rotates the hexagonal rod180to move the L-shaped fingers182between a first position where a portion of the L-shaped fingers182overlies the trays172and a second position, as best shown inFIG. 8, where no portion of the L-shaped fingers182overlies the trays172.

As best shown inFIG. 8, a belt drive186is located in housing188(seen inFIG. 3) attached to plate member160, and includes a first flanged wheel190mounted on the outer side of plate member160, which flanged wheel is coupled to a member192having an extending lever arm193connected to an actuator194. A second flanged wheel196is operably coupled to connecting rod170and rotationally coupled to first flanged wheel190by a belt198. When actuator194presses against lever arm164, it rotates the first flanged wheel180which rotation moves belt198and causes the second flanged wheel196and hence connecting rod170to rotate; this tilts tray assembly166with respect to plates158,160. Actuator200attached to second plate member160causes the entire tray assembly166to pivot about the axis of rod162, while actuator202moves the tray assembly166away from the conveyor12toward a stack discharge location and return the tray assembly166to its starting position after the patties have been discharged.

Referring now toFIG. 2, a motor support204is mounted on the outer wall62of vertical support plate58, and a motor206is mounted on the support. The motor206turns a shaft connected to vertical plate58and two cams—an inner cam208adjacent plate58and an outer cam210between the inner cam and the motor206.

The mounting of upper support18between first vertical plate52and second vertical plate58is apparent inFIG. 4which illustrates the guide wheels130of second L-shaped member106received between rails66of guide64and guide wheels130of first L-shaped member98extending toward upper slot70of second vertical plate member58. Cam follower132rides along the outer surface of inner cam208and the downward movement of the upper support18is limited by the bottom end of slot70. The mechanism for holding the upper support18against cam208is best seen inFIG. 4, and comprises an actuator212mounted on the outer wall56of first vertical plate52which moves a lever arm214attached to a rotatable shaft216mounted between first vertical plate52, and second vertical plate58at an upper edge thereof. From shaft216extend first and second angled arms218which overlie connecting rod94of the upper support. By moving lever arm214, actuator212raises and lowers angled arms218to press down upon the upper support or to move the arms218away from the upper support.

Lower support22, as best seen inFIG. 4, is mounted between first vertical plate52and second vertical plate58with the guide wheels150of the outer sides138of first plate134received between rails66of guide64and the set of guide wheels150on the outer side144of second plate140extending through lower slot74of second vertical plate58. Cam follower152is biased upwardly against outer cam210by a mechanism that includes an actuator220mounted on the outer wall of56of the first vertical plate52connected to a lever arm222which in turn is connected to a shaft224rotatably mounted between the first and second vertical plates52,58on the edge of the plates beneath the conveyor12. Two arms223connect shaft224to first side plate134and second side plate140of lower support22so that, when actuator220moves lever arm222and turns shaft224in a first direction, cam follower152of the lower support22is pressed upwardly against outer cam210and pulled away from outer cam210when shaft224is turned in the opposite direction.

The operation of the stacker will now be described with reference primarily toFIGS. 10though13which illustrate the stacker in various stages of forming a plurality of hamburger patties into stacks and transferring those stacks from a stacking location toward a discharge location. Beginning withFIG. 10, patties16move along conveyor12and fall over the end edge14of the conveyor onto fingers118of upper support18.FIG. 10illustrates one patty16already supported by the fingers118with another about to fall onto the first patty to begin to form a stack. Beneficially, the upper support18and the lower support22are located generally beneath the end edge14of the conveyor12, and thus the stacks that form on the upper and lower supports are also formed generally beneath the conveyor12. This formation of stacks beneath the end of the conveyor advantageously contributes to the compact size of this stacking device because the stacks are formed against the direction of movement of conveyor12. Actuator212rotates lever arm214to turn shaft216to press arms218against the upper support to hold the upper support cam follower132against inner cam208, and, as the radius of cam132decreases while it rotates counterclockwise as viewed inFIGS. 10–13, the upper support18moves downwardly toward the lower support22. The rotation of the inner cam208is based on the rate that the stack is forming as detected by optical detector226, best shown inFIG. 2, so that the top of stack20remains approximately the same distance below conveyor end edge14and ensures that each patty drops a similar distance in a similar manner to form consistent stacks.

FIG. 11illustrates stack20on finger elements154of lower support22. As the upper support18continues its descent, the pair of fingers118of the upper support18supporting the stack will pass to either side of one of the fingers154of the lower support22so that, as the upper support18continues to drop past the lower support22, the stack16will be deposited on the lower support22. Actuator126pivots the upper support18away from the conveyor12so that additional patties16may fall onto the stack on the lower support22.

InFIG. 12, the stack has grown to its finished size, at which point actuator220pivots shaft224to drop the lower support22to cause lower support finger154to pass through the slot176in bottom wall174of one of the trays172of the transfer mechanism24, to leave the stack supported on the transfer mechanism24. In this figure too, the pins118of the upper support18can be seen moving back toward conveyor12to catch the next patty falling therefrom in order to start a second stack rather than allowing it to fall on to the completed stack on the transfer mechanism24. At this point, motor36rotates shaft38to pull movable frame30away from fixed frame28to lengthen the conveyor (effectively moving end edge14away from the next row of patties) and delay the passage of additional patties over end edge. This second stack will be processed in the same manner as was the first stack.

FIG. 13shoes that the transfer mechanism24has rotated and translated away from the conveyor12toward a discharge location228on which the stacks will be deposited. To accomplish this movement, actuator200first pulls and then pushes against lever arm201, as best shown inFIG. 9, to rotate lever arm201in a counterclockwise direction as seen inFIG. 9which, through a gearing mechanism, rotates tray assembly166to the inverted orientation seen inFIG. 13. Actuator194presses against lever arm193to pivot the tray assembly166relative to the transfer mechanism wall158to fully invert the stack20of patties and deposit them onto holder228, which holder has a slot in a bottom support wall to allow covering fingers182to pass therethrough when actuator184moves the covering fingers182away from the stack prior to returning to its starting location beneath the conveyor12in time to receive the next stack of patties from the lower support22.

During the foregoing process, drive36rotates shaft38to move movable frame30along supports34on fixed frame28to position the movable frame portion30and hence the transfer mechanism24for optimal operation. As seen inFIG. 12, where stack20is transferred from the lower support22to the transfer mechanism24, movable frame portion30is closest to fixed frame portion30, and wheels32are positioned near the right edges of supports34as viewed inFIGS. 10–13.FIG. 10illustrates the transfer mechanism24has moved to a point approximately halfway between the conveyor12and discharge location228, and movable frame portion30has also moved in this direction as can be seen from the positions of wheels32on the supports. InFIG. 12, transfer mechanism24has reached discharge location228, and the movable frame portion30has also moved closer to the discharge location as can be seen from the positions of wheels32on the supports34. As discussed above, this motion provides for lengthening and shortening the conveyor as needed to vary the spacing between advancing rows of patties to give the upper support time to move into a stream of falling patties.

Buffer

The buffer portion of the subject system is described in an application entitled “Method And Apparatus For Buffering A Flow Of Objects” filed concurrently herewith and assigned to the assignee of this application.FIGS. 14 and 15illustrate buffer device310which includes a frame312, a drive314and a plurality of carriers316, as best shown inFIGS. 16–20, supported by the frame312. Frame312includes vertical support portions318adapted to support the frame on a horizontal support surface, a generally planar upper support portion320that includes first and second openings322, and a motor support324mounted beneath upper planar portion320.

Drive314includes a motor326mounted on motor support324and operably connected to a drive gear328which turns a continuous drive belt330about a plurality of flanged wheels, including a first wheel332and a second wheel334. First and second wheels332and334each include a center opening336having a notch338for receiving a splined shaft. Two splined shafts340extend from center openings336upwardly through first and second openings322in the frame upper support320.

A bottom plate342having first and second openings344, as best shown inFIG. 18, a peripheral edge346and a raised rail348running around the peripheral edge is mounted on frame upper support320with first and second openings344aligned with openings322in the frame upper support320so that splined shafts340extend though these openings. Wheels350, as best shown inFIG. 15, are mounted on each of the splined shafts which wheels include center openings352shaped to receive shafts340and peripheral grooves354for receiving and holding a drive belt356. The drive belt356preferably has a circular cross section and is formed from a flexible, wear-resistant material, such as urethane.

A top plate358having first and second openings360, a peripheral edge362and a raised rail364running around the peripheral edge is mounted over bottom plate342and spaced apart therefrom by spacers366, with openings360positioned to receive splined shafts340. Bearings368are mounted on top plate356to rotatably secure the ends of shafts340. Thus, motor326turns drive gear328and causes drive belt330to move about first wheel332and second wheel334, which in turn causes splined shafts340and wheels350mounted thereon to rotate and drive drive belt356about a continuous path between bottom plate342and top plate358. Drive belt356preferably has a diameter greater than the width of peripheral grooves354, so that the belt only contacts the wheels about a small portion, less than 180 degrees, of the belt's circumference.

FIG. 14illustrates a plurality of carriers316mounted on the top and bottom plates which carriers comprise trays370supported by trolleys372as best shown inFIGS. 15–17. Each tray370includes a bottom wall374having a centrally located slot376with a slot edge378, a rear wall380and sidewalls382. The trays370are preferably mounted on the trolleys372in a manner that allows for easy removal thereof, so that appropriately sized trays370can be used for the objects being processed. Each trolley372, shown in more detail inFIGS. 16 and 17, includes a body portion386having a lower portion388with a lower end390and an upper portion392angled with respect to the lower portion388. A wall394projects from body lower portion388in the same direction as the angle of the upper portion, and includes a small wall396projecting from its end in the direction of angled upper portion392. A boss398is mounted on upper portion392and supports a shaft400on which a wheel402having a V-shaped peripheral notch404is rotatably mounted and held in place by a retainer406. A wheel support407is connected to wall394, and small wall396supports shaft408on which guide wheel410is mounted for rotation about an axis parallel to lower portion388of body portion386. Projections412extending from the lower side of wall394support two additional guide wheels414, which guide wheels414are mounted for rotation about axes normal to body lower portion388. Guide wheels415are also mounted on the bottom side of wall394, with axes parallel to body portion388and between guide wheels414and body portion388.

A clamp416is mounted on body lower portion388between guide wheels410and notched wheel402, and includes an upper clamp member418pivotably supported on lower body portion388by a shaft420, and a lower clamp member422pivotably supported on a shaft424extending between lower body portion388and small wall396. Both the upper and lower clamp members are coated with, or preferably formed from, a low-friction, wear resistant material, such as UHMW polyurethane. The angular relationship between the upper and lower clamp members, and hence the distance separating the ends of the clamp members, can be adjusted by pivoting the upper clamp member and fixing it in place with fastener426.

The mounting of carriers316on the upper and lower plates is best shown inFIG. 18, wherein trays370are detachably connected to trolleys372, and the trolleys are arranged such that notch404of wheel402on the angled upper portion392of the trolley fits over an edge of raised rail64on the periphery of top plate358, guide wheels410engage the inner edge of raised rail348on bottom plate342, guide wheels415engage the outer edge of raised rail348, and guide wheels414engage the underside of bottom plate342.

The upper and lower members418and422, respectively, of clamp416are attached to drive belt356by placing the belt between the members and clamping the upper member in place so that a small force is exerted against the belt by the clamp members. The force must be great enough that friction between the clamp416and the belt356will keep the trolleys372fixed with respect to the belt when the path of the trolleys372is clear. The force also must be small enough that the frictional force between the belt356and the clamp416can be overcome by the drive motor to cause the belt to slip through the clamp when movement of one or more of the trolleys372is blocked by a stop.

As best shown inFIGS. 18–20, a first solenoid-actuated stop428is mounted on frame312with a trolley-engaging portion430shiftable between a first, release position, shown inFIG. 19, below the lower ends390of the trolley bottom portions388and a second, stop, position, shown inFIG. 20, where the trolley engaging portion430blocks a path of the trolley372by forming a stop against which the lower ends390of the trolleys impact when the stop428is in its stopping position. A second, separately controllable, solenoid-actuated stop434is provided on the other side of the buffer device.

The shifting of the stops428and434between stop and release positions is controlled by a controller436, operably coupled to sensors432and433mounted on frame312below the tray bottom walls394, as best shown inFIG. 18. These sensors are used to count the number of trays passing thereby. The controller436monitors the number of trays370passing over each of the sensors432or433, and causes the first stop428to shift to its stop position when a predetermined number of trays has passed. For example, when the buffer receives four stacks of patties at a time from a stacker, the trays370will be released in groups of four. Similarly, when stacks are removed in groups of three, the controller436shifts the second stop434into the blocking position and only allows the trays370to pass in groups of three. The operation of the stops428and434is coordinated with the operation of the stacker10and stack transfer device510so that, in the embodiment described herein, at least four empty trays are always available to receive incoming stacks of patties and that at least three stacks of patties are present at the second stop434to be removed by a stack transfer device510. An optical sensor435is also provided for detecting patties on the trays as they approach the side of buffer310facing stacker10. Since these trays370should all be empty, an alarm occurs or the system shuts down when full trays are seen approaching the loading position.

As best shown inFIG. 50, two additional sensors444and446are also provided to help ensure that enough trays370are present upstream of stop428to receive incoming stacks of patties and that the correct number of stacks of patties are available for removal by a stack transfer device. Thus, for example, as sensor428is counting the passage of four trays370, sensor444upstream of sensor428is counting the passage of empty trays toward sensor432and stop428. Controller436is preferable coupled to the controller for a transfer device that brings stacks of patties to the buffer device310and configured so that stacks of patties will not be transferred to buffer device310until sensor444has detected the passage of four trays370. Thus, in the event that a problem arises that prevents four empty trays from lining up behind stop428, the transfer device will not attempt to transfer stacks of patties to the buffer device310. This reduces the likelihood that patties will be dropped or otherwise mishandled during processing. In a similar manner, sensor446counts trays370approaching sensor433, and as sensor433is counting the release of three empty trays370, for example, sensor446is counting approaching trays to ensure that at least three full trays are present at stop434and that at least three stacks are available for removal. Controller436is preferably connected to the controller for the downstream stack transfer device and prevents stacks from being removed from the trays stopped at stop434until three stacks are present for removal. The number of stacks arriving at and leaving the buffer device310can be varied, and the position of sensors444,446is adjustable so that these sensors can be placed near the location where the last of a given group of trays370will be found when the system is operating properly.

In a second embodiment, sensors432and433are used both to count the number of trays passing thereby and to detect, optically, for example, whether the tray adjacent the sensor is full or empty, based upon whether slot376is blocked. The controller436monitors the status of the trays370passing over each of the sensors, and causes the first stop to shift to its stop position whenever an empty tray is detected and to shift to its release position when a full tray is detected. Similarly, controller436shifts the second stop into the stop position when a full tray is detected by sensor433and into the release position when actuated in an opposite manner, that is, set to prevent the passage of full trays while allowing empty trays to pass.

In operation, motor326drives drive belt330, turning first and second wheels332,334and rotating shafts340and wheels352mounted thereon. This in turn causes drive belt356to move continuously about the periphery of buffer310between plates342and358. The carrier trolleys372are clamped to belt356tightly enough that they are pulled about the peripheries of the upper and lower plates by the movement of the belt. The trolleys are guided by the engagement of trolley wheels402with upper plate raised rail64and the engagement of guide wheels410,412and414with the peripheral portion346of lower plate342. Stops428and432are selectively moved into and out of the path of travel of the trolleys and, when positioned in the stop position, prevent trolleys from moving past the stops. The motor326continues to operate at a continuous speed, however, sliding belt356through clamps416even when all trolleys are prevented from moving by the position of the stops. The urethane from which belt356is formed is sufficiently wear resistant that it provides reliable operation even after many hours of continuous use. And, as the relative positions of clamp upper member418and lower member422are adjustable, the clamps can be repositioned in the event that the diameter of belt356decreases slightly after a long period of use to maintain the proper pressure on the belt.

The operation of the subject system will now be described with particular reference toFIGS. 21a–21hwhich illustrate the operation of the system set up for use with a patty stacker that forms four stacks of patties simultaneously which patties must be packed in boxes that are three patties wide. Thus the buffer310will receive stacks of patties four at a time from a first direction, shown by arrows438inFIG. 21A, on a first side of the buffer310and present them for removal three stacks at a time on a second side of the buffer310where they are removed in a the direction of arrows440inFIG. 21C.

FIG. 21Ashows four trays370a,370b,370cand370don a first side of buffer310which trays have received four stacks442of hamburger patties from the transfer mechanism24. Controller436causes stop428to move between stop and release positions in order to release carriers in groups of four at predetermined intervals. After four stacks of patties are received in trays370a–370d, stop428shifts to its release position and allows these carriers to pass. The fifth carrier,470e, which is empty, and the carriers behind it, are stopped by stop428for a predetermined period of time, a period long enough for theses carriers to receive four more stacks of patties from the stacking machine.

As shown inFIG. 21B, additional carriers370fand370gimpact against stopped carrier370eand are held in this position as belt356slips through clamps416on each trolley. Carriers370e–gremain stopped for a predetermined amount of time. Meanwhile, carriers370a–dhave been carried around buffer310by belt356toward a second stop434that blocks the path of the trays, and tray370aimpacts against the second stop. Trays370b–dimpact against stopped tray370aand are also brought to a stop with drive belt356sliding freely through clamps416on each of the stopped trays.

As shown inFIG. 21C, a second transfer device510, as later explained, removes three stacks of patties from carriers70a,70band70cin the direction of arrows140, and the first transfer device24places four additional stacks of patties on carriers70e,70f,70gand70hon the first side of the buffer310. After a predetermined time, carriers70a–cwill be empty, and therefore the controller cause these three trays to be released, while the next tray (the last full tray) is stopped. Full carriers70e,70f,70gand70hare released by first stop132inFIG. 21Cand moved around the buffer until they impact full carrier70dheld up at second stop134resulting in the positioning of trays shown inFIG. 21D.

FIG. 21Eshows that three stacks of patties have been removed from carriers370d,370eand370fand that additional stacks of patties have been placed on carriers370i,370j,370kand370a. Four full carriers are released by stop428and three empty carriers are released by stop432as described above resulting in the arrangement of carriers shown inFIG. 21f. As shown inFIG. 21G, three additional stacks of patties are removed from trays370g,370hand370iand these now-empty carriers are also released. Full carriers370j,370kand370aremain stopped at stop432. Three additional stacks of patties will be removed from carriers370a,370kand370jas shown inFIG. 21Hwhile an additional four stacks are added to trays370c,370d,370eand370fat the first side of the buffer310, and from there the process continues repeatedly as described above.

Because of the stops428and434, the buffer310is able to permit patties to be received in trays392in essentially any number from transfer device24and to be removed by transfer device510in groups of essentially any number.

Stack Transfer Device

The stack transfer portion of the subject system is described in an application entitled “Stack Transfer Device” filed concurrently herewith and assigned to the assignee of this application.FIG. 22shows transfer device510which includes guide tracks512, a drive514, and a carrier516which is moved linearly back and forth along the guide tracks512by the drive514. Guide tracks512comprise a first pair of feet518having aligned openings520, best seen inFIG. 25, and a second pair of feet522having aligned openings524best seen inFIG. 24. Two lower rail members526connect the first and second pairs of feet, and two upper rail members528are mounted above lower rail members526to define a guide channel530therebetween.

Drive514comprises a motor532, a drive shaft534extending through aligned openings520in the first pair of feet, first and second geared wheels536coupled to the drive shaft534, an axle538extending between aligned openings524in the second pair of feet, and first and second idler wheels540mounted at either end of axle538. A first belt544extends between one of the geared wheels536and one of the idler wheels540, and a second belt546extends between the other one of the geared wheels536and the other idler wheel540. The portions of belts544and546facing the guide tracks512include an attachment plate548as best shown inFIG. 23. Motor532is reversible, and can be driven in a first direction to rotate the geared wheels to drive the belts544and546in a first direction, to move the attachment plate548from a first end550of the guide tracks512to a second end552of the guide tracks, and in a second direction to move the attachment plate548back to the first end550. Carrier516is mounted on the guide tracks512and attached to attachment plate548, so that it can be driven between first end550and second end552by motor532.

Carrier516comprises a support frame554and a pivot frame556that is pivotally connected to support frame554for pivoting motion about a pivot axis558between a first position, shown inFIG. 23, where the support frame is oriented at a right angle to the guide tracks512and generally vertically when support feet518and522rest on a horizontal floor or other support surface, and a second position, shown inFIG. 26, where the frame is tipped about 30 degrees from vertical. As best seen inFIG. 24, support frame554includes first and second spaced plate members560,561and a pair of wheels562carrying the frame and rotatably attached to each attachment plate548, which wheels are sized to fit in channel530between the upper and lower rail members of the guide tracks512. A dog564depends from each of the attachment plate548which dogs564are securely fastened to each of the attachment plates548on the first and second belts544and546. A lower strut566is connected between and carried by the first plate560and second plate561.FIG. 24shows a first axle568projecting inwardly from plate member560and a second axle570is supported by plate member561, with an inner end572projecting toward first axle568and an outer end574projecting from the opposite side of the plate member561. First axle568and second axle570are coaxially aligned with pivot axis558.

Pivot frame556includes first and second side plate members575connected by a lower strut577, and the side plate members575each include an upper portion to which the axles568and570are attached. First side support578projects upwardly from first plate560and is fixedly attached to plate560. A second side support580, parallel to the first side support, is fixed to outer end574of second axle570. The upper ends of the first and second side supports are connected by a strut582, and plate members584are attached to either end of the strut582which plate members form attachment points for elements described below.

A gripper mechanism586is carried by pivot frame556and comprises a lower gripper member588and an upper gripper member590as best seen inFIG. 22. In the preferred embodiment, the lower gripper member588includes a gripper frame592slidingly supported between plate members560and561of pivot frame556, and first and second linear actuators594, preferably pneumatic actuators, connected between the pivot frame556and the gripper frame592for moving the gripper frame592relative to the pivot frame556. Four stack supports596, as best shown inFIG. 24, are mounted on the gripper frame592, each of which includes a stack-engaging top portion598adjustably connected thereto. As all of the stack supports596are connected to the gripper frame592, they all move in unison when actuators594move the frame. However, it is within the scope of this invention to use individually controllable actuators as well.

Upper gripper member590, as best seen inFIG. 22, comprises a strut600connected between plate members584at the top ends of the first and second side supports578,580to which four independently controllable pneumatic actuators602are attached at various selectable positions along rod600, which positions are selected so that the actuators602on the upper gripper member590are aligned with the stack supports596on the gripper frame592. Each actuator602includes a tubular housing604within which a piston606is mounted for reciprocal motion with respect to the housing. At the end of each piston is mounted a stack-engaging plate member608as best shown inFIG. 24. The actuators602are connected to a suitable controller, not shown, which moves the pistons606to move the plate members608between first and second positions with respect to the housing604. Preferably the same controller that controls the motion of the actuators594controls the lower gripper member so that the stack-engaging members598of the gripper frame592can be moved toward the stack-engaging plates608of the upper gripper590while the stack-engaging plates608of the upper gripper590are being moved toward the stack-engaging members598of the lower gripper588to grip a stack of objects, such as frozen hamburger patties, therebetween. The controller also controls the separation of the upper gripper590and the lower gripper588. A tipper actuator610is connected between support frame554and pivot frame556to tip or pivot the pivot frame between the first and second positions.

The operation of transfer device510will now be described with reference toFIGS. 26–30which figures show device510positioned between buffer device310and matrix former818. The buffer device310includes a plurality of individual trays70for supporting a plurality of stacks20of frozen hamburger patties, which stacks each include a bottom708and a top710. Only one of the trays and one stack of patties is visible in these figures; however two other holders holding two other stacks of patties are positioned therebehind. The lower portion of each tray920is angled with respect to the horizontal to help keep the stacks20of patties16in place while the trays70are moved around the buffer device310, and the bottom of each tray includes a slot that is narrower than the diameter of the patties in each stack but wide enough to allow the stack-engaging tops598of the lower gripper member to pass through the slots and contact the bottoms708of the stacks. The matrix former818has a horizontal bottom wall920and upstanding sidewalls924,926between which the stacks of patties are placed for further processing. The bottom wall920includes a plurality of slots narrower than the width of the patties but wider than the stack-engaging tops598to allow stacks of patties to be placed on the bottom wall920inwardly from the edge thereof. While the transfer device is well suited for use in this environment, it could be used to transfer stacks between other supports as well, one, both, or neither of which are inclined with respect to horizontal. Furthermore, the matrix former can be adjusted to accommodate different numbers of rows and/or rows having different numbers of stacks.

FIG. 26shows a stack16of frozen hamburger patties supported on a tray70of a buffer device310. Carrier516is positioned at the second end552of the guide track and tilted to the second position, wherein the plane of the stack-engaging surfaces of the lower gripper588and the upper gripper590are inclined at about a 30 degree angle from vertical and parallel to tray704. Lower stack-engaging top member598is positioned directly under stack bottom708, while upper stack-engaging plate608is positioned over stack top710.FIG. 27shows the configuration of device510after actuators594have raised the lower gripper588so that the stack-engaging tops598of the lower gripper588are in contact with stack bottoms708, and after actuators602have lowered stack-engaging plates608into contact with top surfaces710of the stacks20. The upper and lower grippers590and588, respectively, are moved toward one another firmly enough to securely hold the stack20therebetween. The distance that the upper and lower grippers are moved toward one another can be a constant based upon the height of the stacks706, or, alternatively, a pressure sensor can be provided which will stop the movement of the grippers588and590when a predetermined pressure is applied to the stacks20. The pressure applied to the stacks20must be sufficient to keep the stacks20from falling apart when they are rotated from an inclined to a generally vertical orientation.

FIG. 28shows carrier516after tipper610has pushed pivot frame556back to the first position and drive514has moved the carrier516to the first end550of the guide track512and positioned the bottom of stack20over the horizontal matrix former bottom wall920.

FIG. 29shows the upper and lower grippers590and588, respectively, after they have separated to release the stacks onto horizontal platform920, whileFIG. 30shows a second stack716of patties about to be placed on the platform920. The controller for the carrier can be programmed to leave additional rows of stacks at other locations if more than two rows of stacks are needed.

Packing Machine

The packing machine portion of the subject system is described in an application entitled “Method And Apparatus For Packing” filed concurrently herewith and assigned to the assignee of this application.FIG. 31shows a packing apparatus designated generally by the numeral810which includes an empty-box feeding conveyor812, a packed-box discharge conveyor814, a lift mechanism816, and a matrix former818.

Lift mechanism816, as best shown inFIG. 32, includes a reversible motor820for turning a drive shaft822which is supported on one end by motor820and on the other by a bearing824mounted on a support (not shown). First and second flanged wheels826are mounted on shaft822for rotation therewith, and a second shaft828is rotatably supported by first and second bearing plates830mounted to supports (not shown) parallel to the drive shaft822. First and second flanged wheels832are mounted on second shaft828and aligned with the flanged wheels826on the drive shaft822. First and second belts834extend between aligned pairs of flanged wheels826and832on the shafts822and828such that shafts822and828are rotated simultaneously when motor820turns drive shaft822. Parallel guide tracks836are mounted adjacent the belts834, each track836defining a channel facing toward the channel of the other track836.

Lift platform840includes a first sidewall842, a second sidewall843, a top support844, and a bottom support846supported for rolling movement along the guide tracks836by wheels848, as best shown inFIG. 37, and is clamped to belts834by clamps850. Thus, motor820moves lift platform840between raised and lowered positions on guide tracks836by rotating shaft822. Motor controller851controls the operation of motor820, and thus the position of lift platform840with respect to the guide tracks836and the matrix former818.

Lift platform840, as best shown inFIG. 32, further includes a pivoting platform852mounted on lift platform840for pivoting movement with respect to platform840. Platform852includes a base frame854, including a projecting arm856and a sidewall858. A first axle860extends from first sidewall842and connects to sidewall858, while a second axle862extends from second sidewall843and connects to projecting arm856. The axles860and862are coaxial. Under the influence of appropriate actuators, pivoting platform852may be pivoted between first and second positions with respect to lift platform840.

Pivot platform852further includes a guide track864, as best shown inFIG. 35, connected between sidewall858and sidewall843, a first fixed wall865adjacent track864and a second wall866slidingly connected to track864. An actuator868, shown inFIG. 35, is mounted adjacent track864, for moving sliding wall866toward and away from fixed wall865to grip a box placed therebetween. A roller support870, comprising a plurality of free-spinning rollers, is mounted on base frame854between sidewalls843and858. Four posts872extend from walls865and866which posts are mutually parallel and arranged generally in a square. The top of each post872includes a finger874pivotally attached thereto, and an actuator876connects each finger874to the top of sidewall865or sliding wall866, so that the fingers874can be pivoted between first and second positions with respect to the sliding walls by the actuators876and function as grippers for gripping the top edge of a box.

A crank arm880, as best shown inFIG. 31, is attached to the end of axle860, and a first cylinder and piston assembly882extends between crank arm880and sidewall842of lift platform840. A second cylinder and piston assembly884extends between pivot platform852and sidewall842. Operation of the first and second cylinder and piston assemblies882and884moves pivot platform852between first and second positions.

Referring now toFIGS. 33,34and36, matrix former818can be seen to comprise a reversible motor890for rotating a drive shaft892approximately 180 degrees between first and second positions. Plate894, having first and second ends896, is supported on shaft892, and first and second arms898are attached to the ends896of plate894. Arms898are connected to a shaft900by a triangular plate member902. One end of shaft900is connected to a first vertex of plate member902, while arms898are connected to the other two vertices of the triangular plate member902. Shaft900is securely supported by two bearing plates904fixedly mounted to a support structure906, as best shown inFIG. 31. An L-shaped support908depends from shaft900and includes a projection910for supporting an actuating assembly912. Actuating assembly912comprises side plates914connected by telescoping cylinders916and an actuator918. The matrix former818, as best shown inFIG. 33, further includes a patty-receiving platform920having three slots922therein, a first sidewall924connected to one of the side plate914, and a second sidewall926connected to the other of the side plates914. (The slots922are narrower than the width of the patties to be placed thereover.) The sidewalls924and926are movable toward and away from each other by operation of the actuating assembly912which is attached to the two side plates914.FIG. 36illustrates three stacks16of hamburger patties between the sidewalls924,926of the matrix former818in a closely spaced relationship.

In operation, a first set of three stacks of hamburger patties is placed onto receiving platform920, one stack over each of slots922, by stack transfer device510. A second set of three stacks is then placed on receiving platform920next to the first set of stacks by the stack transfer device. The stacks are formed with a spacing between them, and are thus transferred to the receiving platform920with a spacing. To remove or substantially decrease this spacing, controller851operates actuator918to move side plates914, and thus first and second sidewalls924and926which are connected to side plates914, toward each other to slide the patties toward one another and form a tighter matrix of patties.

FIGS. 37 through 45illustrate the interaction of the lift mechanism816and the matrix former818during one patty boxing operation. InFIG. 37, system810can be seen with an empty box930, having an opening932, that has been released to slide down box feed roller conveyor812toward and onto roller support870of lift platform840. At this stage, matrix former818already holds six stacks (two rows of three stacks each) of hamburger patties. Once box930is received on roller platform870, sliding side wall866is moved towards wall865by actuator868, until it engages the sidewalls of the box and holds box930securely on platform870. Actuators876pivot fingers874and move them into the opening932of box930, where they further secure the box to the roller platform870and help hold down any flaps that the box might have. Platform870is then pivoted to the position shown inFIG. 38, with its surface generally normal to guide tracks836. First cylinder and piston assembly882, with a first end connected to first sidewall842, presses against crank arm880on first axle860, which causes pivoting platform852to pivot about the axes of first axle860and second axle862from the position shown inFIG. 38to the position shown inFIG. 39so that roller platform870is positioned over matrix former818and with the opening932of box930facing the stacks of patties on the matrix former. Sliding sidewall866and fingers874, held in place by actuators876, keep box930secured with its bottom wall against roller platform870.

Controller851next causes motor820to rotate shaft822, in order to move belts834and thus platform870toward matrix former818until the sidewalls924,926of the matrix former818and the patties on the matrix former surface920are inside box930, as best shown inFIG. 40. In this position, shaft900of the matrix former is coaxially aligned with axles860and862of the lift platform.

Next, matrix former motor890actuates to rotate plate894and move one of the arms898toward shaft900and the other of arms898away from the shaft900, thus rotating triangular plate902and shaft900connected thereto. This causes the receiving platform920to pivot about the axis of shaft900. Simultaneously, first cylinder and piston assembly882and second cylinder and piston assembly884contract to pivot roller support platform870about axles860and862, so that the box930on the roller support platform870and the patty support platform920of the matrix former remain essentially parallel as they rotate through 180 degrees to the position shown inFIG. 41. The patties, which had been supported by receiving platform920and covered by box930, are in this new orientation supported by box930with the receiving platform920positioned thereover.

Motor820next rotates shaft822to move roller support platform870and box930thereon away from patty support platform1920and away from shaft822until the patty support platform920is clear of the box930, as best shown inFIG. 42. Motor890rotates shaft900to return the patty support platform920to its starting orientation as best shown inFIG. 43. Roller support platform870is next raised to the position shown inFIG. 44, generally parallel to the surface of discharge conveyor814. Actuators876pivot fingers874out of top opening932of the box930and sliding sidewall866moves away from box930. The box930may then slide under the force of gravity off roller platform870and onto the adjacent discharge conveyor814as best shown inFIG. 45. The lift platform840is then raised back toward the feed conveyor812to receive another box and start the cycle again.

FIGS. 46–49show in more detail the transfer of the stacks20of patties16from the matrix former818to the box930.FIG. 46is a sectional view showing the inside of the box930and the matrix former818when the box930is held over the matrix former818as shown inFIG. 39. As can be seen inFIG. 47, the support platform920of the matrix former fits within the inside of box930, with a small amount of clearance, and at about the level of opening932.FIG. 48shows the inside of box930when the matrix former818and lift platform840are positioned as inFIG. 41, so that the stacks20of patties are now resting on the bottom of box930.FIG. 49corresponds to the position of the matrix former818and lift platform840shown inFIG. 42.

The present invention has been described herein in terms of a preferred embodiment. However, numerous changes and additions to this embodiment will become apparent to those skilled in the relevant arts upon a reading and understanding of the foregoing description. It is intended that all such changes and additions be included within this invention to the extent that they are covered by scope of the several claims appended hereto.