Patent Document

This application claims the benefit of provisional application U.S. Serial No. 60/309,272 filed Aug. 1, 2001. 
    
    
     TECHNICAL FIELD OF THE INVENTION 
     The invention relates to conveyors for positioning articles, and more particularly relates to a conveyor system for positioning meat patties from a feed conveyor onto a downstream conveyor. 
     BACKGROUND OF THE INVENTION 
     Conveyor systems are known which include a feed conveyor arranged to receive a stream of meat patties from a meat patty-forming machine in a grid pattern having a first width, and which deposit the stream onto a downstream conveyor that is arranged below and at a right angle to the feed conveyor. The downstream conveyor has a wider width and a slower operating speed. The downstream conveyor is typically used for treating the patties, such as for conveying the patties through a thermal treating unit, either a heating or a cooling unit. 
     The feed conveyor is controllably extendable and retractable to distribute the stream in a longitudinal direction onto the downstream conveyor, in the lateral direction across a width of the downstream conveyor. The feed conveyor includes a wire mesh conveyor belt having a belt accumulation arrangement located beneath the top surface of the conveyor. 
     The amount of belt storage, and effectively, the length of the top conveying surface, of the feed conveyor are controlled by movement of a carriage. The carriage carries an idler roller or pulley that is wrapped by the belt. The carriage is moved by a pneumatically controlled cylinder. The conveyor system is operated using pneumatic controls. The carriage retract distance is set by a limit switch. The carriage retraction speed and advancement speed are controlled by pneumatic flow control. The retraction of the carriage is initiated by an electric photo-eye. The conveyor belt circulating speed is controlled by variable speed pulleys. 
     Although the aforementioned system operates effectively, the present inventors have recognized the desirability of providing a system that is more easily adjusted and controlled, and can be more cost effectively manufactured, and which can be more efficiently and effectively operated. 
     SUMMARY OF THE INVENTION 
     The invention provides a feed conveyor for depositing articles onto a downstream conveyor, comprising: an endless circulating belt having an upper conveying surface; a roller controlling a belt accumulation region of the endless circulating belt, the conveying surface having an upstream region adapted to receive a stream of articles in rows across a lateral direction of the belt, the belt circulated to move the rows in the longitudinal direction to an end of the conveying surface, wherein the endless belt is turned over at the end, wherein circulation of the belt passes the rows off of the conveying surface to be deposited onto the downstream conveyor, and the longitudinal position of the end is movable between an extended position and a retracted position passing across at least a portion of a transverse dimension of the downstream conveyor by longitudinal positioning of the roller; a first electric motor and a traction device, the traction device engaged to be translated by the first electric motor, the roller mechanically connected to the traction device to be moved longitudinally thereby; a second electric motor, wherein the conveying surface is circulated by mechanical communication from the second electric motor; and a controller operationally connected to the first and second electric motors to precisely control the conveying speed of the conveying surface and the position of the end. 
     The invention also provides a system for depositing patties onto a downstream conveyor, comprising: a patty-forming machine having a reciprocating mold plate and a mechanism to eject patties from the reciprocating mold plate; a feed conveyor having an endless circulating belt with an upper conveying surface and a roller controlling a belt accumulation region of the endless circulating belt, the conveying surface having an upstream region adapted to receive a stream of patties from the patty-forming machine in rows across a lateral direction of the belt, the belt circulated to move the rows in the longitudinal direction to an end of the conveying surface, wherein the endless belt is turned over at the end, wherein circulation of the belt passes the rows off of the conveying surface to be deposited onto the downstream conveyor, and the longitudinal position of the end is movable between an extended position and a retracted position passing across at least a portion of a transverse dimension of the downstream conveyor by longitudinal positioning of the roller; a first electric motor and a traction device, the traction device engaged to be translated by the first electric motor, the roller mechanically connected to the traction device to be moved longitudinally thereby; a second electric motor, wherein the conveying surface is circulated by mechanical communication from the second electric motor; and a controller operationally connected to the first and second electric motors to precisely control the conveying speed of the conveying surface and the position of the end. 
     According to an exemplary embodiment, the present invention provides a feed conveyor operable in a first direction to deposit a stream of articles across a width of a downstream conveyor operating along a second direction, the second direction being at an angle to the first direction. The feed conveyor is an extendable conveyor that is accurately controlled for circulating speed, extension speed and retraction speed, to deposit articles transversely onto the downstream conveyor in a tightly spaced, grid pattern. The conveying speed of the feed conveyor is controlled by a first servomotor, and the extension and retraction speed are controlled by a second servomotor. 
     The feed conveyor includes a wire mesh conveyor belt having a belt accumulation arrangement located beneath the top surface of the conveyor. 
     The amount of belt storage, and effectively, the length of the top conveying surface, of the feed conveyor are controlled by movement of a carriage. The carriage carries an idler roller or pulley that is wrapped by the belt. 
     The feed conveyor is driven to convey at a precise speed by the servomotor. The carriage is connected to an endless belt drive that is precisely driven by the servomotor in both the extension and retraction directions. 
     According to the invention, a controller acts as an operator interface and as an automatic control. The desired extension and retraction distance is set by a keypad entry. The articles size is also set by a keypad entry. The speed of the articles entering the feed conveyor is input automatically. The home position of the carriage, the fully extended position of the feed conveyor, is input by a proximity sensor. The controller calculates the optimal article spacing using the retraction distance and the article size multiplied by a maximum whole number of articles to be spaced transversely across the downstream conveyor. The controller operates the servo controls such that carriage advancement or retraction speed, carriage advancement and retraction acceleration and deceleration, and carriage stroke, are all closely controlled. The carriage belt speed is closely controlled to match the input speed of articles fed onto the feed conveyor. The carriage retraction initiation is also controlled by the controller. 
     The present invention is particularly advantageous as applied to meat patties formed by a meat patty-forming machine such as a FORMAX F-26 machine available from Formax, Inc. of Mokena, Ill. and/or as described in U.S. Pat. Nos. 4,182,003 and 4,821,376, and/or PCT WO99/62344. 
     The patties are formed by the patty-forming machine and deposited onto the feed conveyor. The feed conveyor includes a circulating wire mesh belt that delivers a grid pattern stream of formed patties to an end of the conveyor wherein the patties are deposited row by row onto the downstream conveyor as the conveying surface of the feed conveyor is retracted across a width of the downstream conveyor. Both the feed conveyor and the downstream conveyor are continuously circulating. The patties deposited on the downstream conveyor are actually deposited in a slight angular grid pattern due to the continuous movement of the downstream conveyor during deposition of the patties thereon. 
     The circulating speed of the feed conveyor is servo controlled to match the patty output of the forming machine. A proximity sensor acts to sense the reciprocation of the mold plate of the forming machine to adjust the speed of the feed conveyor to achieve a closely-spaced, non-overlapping, continuously grid pattern of patties on the feed conveyor. The advancing speed of the end of the feed conveyor is closely controlled to be about equal to the circulating speed of the conveyor, and the retracting speed is closely controlled to precisely deposit rows of patties in a closely spaced grid positioning on the downstream conveyor. 
     Numerous other advantages and features of the present invention will become readily apparent from the following detailed description of the invention and the embodiments thereof, from the claims, and from the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of a conveying system of the invention; 
     FIG. 2 is a schematic sectional view of the conveying system of FIG. 1; 
     FIG. 3 is an enlarged perspective view of a portion of the conveying system of the invention; and 
     FIG. 4 is a plan view of an alternate conveying system according to the present invention; and 
     FIG. 5 is a schematic block diagram of a control system for the conveying systems of FIGS. 1 through 4. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     While this invention is susceptible of embodiment in many different forms, there are shown in the drawings, and will be described herein in detail, specific embodiments thereof with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific embodiment illustrated. 
     FIGS. 1-3 illustrate a first embodiment conveying system  10  of the present invention. The system  10  includes a feed conveyor  14  that deposits articles, such as meat patties  16 , onto a downstream conveyor  18 . The feed conveyor  14  receives the patties  16  from a meat patty-forming machine  24 . As an example, the machine  24  delivers a closely spaced, grid pattern stream of patties  16 . 
     The feed conveyor  14  includes an endless belt, wire mesh belt  30 . The wire mesh belt  30  forms a top conveying region or surface  34  and a bottom region  38 . The bottom region  38  has a portion wrapped around a movable roller or idler pulley  42 , effectively creating a belt accumulation region  46 . Movement of the pulley  42  controls the extension or retraction of the top region  34 , and the position of an end  50  of the top region  34 . The top region  34  is turned over to the bottom region  38  at the end  50  by use of a roller or axle  51 . 
     The pulley or roller  42  is rotationally connected by an axle  43  (shown schematically by a dashed line in FIG. 4) to carriages  54   a , 54   b . A first electric motor  62  is operatively connected to a traction system for moving the carriages  54   a ,  54   b . According to a preferred embodiment, the traction system comprises a pair of endless belts, positioning belts  58   a ,  58   b . The carriages  54   a ,  54   b  are connected to the positioning belts  58   a ,  58   b . The first motor  62  is operatively connected by a belt  66  to drive the positioning belts  58   a ,  58   b . The belt  66  is wrapped around a drive pulley  63  which circulates the belts  58   a ,  58   b  via an axle  59  and sprockets or pulleys  64   a ,  64   b . The first electric motor thus controls the retraction and extension of the end  50  via movement of the carriage  54  and the pulley  42 . 
     A second electric motor  70  is operatively connected by an endless belt  74  to a drive pulley  78  of the belt  30 . The second electric motor  70  drives sprockets  79  to drive the belt  30 . The second electric motor  70  closely controls the speed of circulation of the wire mesh belt  30 . 
     The electric motors  62 ,  70  preferably drive the respective belts  66 ,  74  via gear boxes  62   a ,  70   a . The electric motors are preferably precise positioning motors, such as servomotors, that incorporate numerical encoders for precise control. For example, the motor  62  communicates exact positioning information or feedback to a controller  100  for precise control of the end  50  of the conveyor during both advancement and retraction. The motor  70  communicates exact positioning information or feedback to the controller to ensure precise coordination between the belt speed and the forming machine patty-output speed. 
     The controller  100 , such as a programmable logic controller (PLC), a microprocessor, a CPU or other control device, is signal connected to the motors  62 ,  70 . The controller  100  can also receive operator input from a keypad  100   a  (FIG.  5 ). A proximity sensor  110  senses the position of the carriage, with the end  50  fully extended as the “home” position. The sensor  110  is also signal-connected to the controller  100 . The controller  100  can ensure a proper initial position of the feed conveyor end  50  by automatically extending the end  50  using the motor  62 , until the home position is sensed by the sensor  110 . 
     A proximity sensor  120  is mounted to the patty-forming machine mold plate to sense reciprocation of the plate. The sensor  120  is signal-connected to the controller  100 . The controller  100  adjust the speed of the motor  70  to ensure that the machine output of patties onto the conveyor  30  matches the speed of the conveyor to achieve a closely packed grid pattern of patties on the conveyor  30 . 
     Adjacent to the end  50  of the conveyor  30 , is a ramp region  130 . The ramp region  130  is angled downwardly toward the second conveyor in order to gently deposit meat patties onto the conveyor. The angle of the ramp region  130  is manually adjustable in order to ensure that a gentle deposit occurs during retraction, and to ensure noninterference with patties on the downstream conveyor during advancement of the end  50 . 
     The controller  100  closely controls the movement of the motor  62  so that the rows  140  of patties are deposited onto the downstream conveyor  18  as the end  50  is retracted, in a closely spaced grid pattern. The operator inputs the retraction distance of the end  50  and the patty size by keypad entry. The controller  100  calculates the optimal patty spacing using the retraction distance and the patty size multiplied by a maximum whole number of patties to be spaced transversely across the downstream conveyor  18 . For simplicity, the grid pattern shown in FIG. 1 is shown as a straight grid pattern having a straight row alignment  141 . In fact, due to the continuous movement of the conveyor  18  the alignment will be an angled alignment  142 . Once fully retracted, the controller  100  closely controls the speed of the motor  62  so that the leading row of patties, the row close to the end  50 , is not prematurely deposited until the end  50  reaches his fully extended position. Once the fully extended position is reached, retraction begins immediately thereafter to deposit the next group of patties. The retraction and extension (stroke) of the conveyor  14  is reciprocal to fill the downstream conveyor. 
     As illustrated in FIG. 5, the controller  100  also can receive a speed signal from the downstream conveyor  18  and can then adjust either the downstream conveyor speed via first and/or second drives  101 ,  102 , or first, second and third drives  101 ,  102 ,  103 , and/or adjust the forming machine patty output speed and the motors  62 ,  70  such that all speeds are coordinated to achieve an optimally filled conveyor  18 . The embodiment shown in FIGS. 1 through 3 utilizes one drive  101  for the downstream conveyor. 
     FIG. 4 illustrates an alternate embodiment  200  wherein the downstream conveyor is replaced by a conveyor  206  having a first perpendicular conveyor section  211  beneath the feed conveyor  14 , an arcuate conveyor section  212  connected to an in-line conveyor  216 . The feed conveyor  14  is otherwise identical to that described for the first embodiment. The first conveyor section  211  is driven by the first drive  101  and the arcuate conveying section  212  is driven by the second drive  102 . The arcuate section  212  requires a different drive to independently adjust the speed of the arcuate section  212 . The in-line conveyor  216  can be driven by a third drive  103 . 
     As illustrated in FIG. 5, the controller  100  can control the first and second drives  101 ,  102 , or all three drives  101 ,  102 ,  103 , and/or adjust the forming machine patty output speed and the motors  62 ,  70  such that all speeds are coordinated to achieve an optimally filled in-line conveyor  216 . Optionally, the third drive  103  can be manually speed-controlled. 
     Shuttle Conveyor General Description of Operation 
     According to a preferred embodiment, the feed conveyor or “shuttle conveyor” is controlled with two servomotors  62 ,  70 . The first servomotor  62  controls the shuttle movement onto the downstream conveyor  18 . The shuttle conveyor  14  can be located in the home position automatically using the shuttle home proximity switch  110 . The shuttle distance is entered via the keypad  100   a . The shuttle advance speed, retract speed, acceleration, and deceleration are all automatically calculated. The second servomotor  70  controls the speed of the wire belt conveyor  30 . This speed can be automatically calculated using two pieces of information. This first parameter is the patty size. This parameter is entered via the keypad  100   a . The second parameter is the forming machine speed. This is calculated automatically with the patty forming rate proximity switch  120 . This allows the shuttle conveyor to increase and decrease speed automatically to match the forming machine speed. 
     The preferred embodiments of the invention allow for a number of advantages in operation, such as: 
     1. The parameters entered via the keypad can be stored as product codes. This allows a one-time setup and fast changeovers. 
     2. Multiple product codes can be stored, such as 20 product codes. 
     3. The shuttle conveyor can be automatically set by a home sequence. 
     4. The downstream conveyor speeds can be automatically adjusted. 
     5. The true positioning control of the shuttle conveyor allows for automatic shuttle conveyor retract initiation. 
     6. The controller includes the ability to stop the retraction of the shuttle conveyor, for any empty rows produced by the forming machine, thus maximizing downstream belt coverage. 
     From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims.

Technology Category: 7