Abstract:
An improved stopping mechanism is provided for a conveyor that accepts one or more streams of product input and converts the one or more streams to a format that is suitable for automatic loading to a subsequent machine, wherein a stack of slices must be temporarily stopped on the conveyor while moving. The stopping mechanism includes a lower stop having a lower stack-engaging portion and a lift portion, the lift portion selectively actuatable to elevate the lower stack-engaging portion to engage a bottom surface of the stack and to lift the stack above the conveying surface. The stopping mechanism further includes an upper stop having an upper stack-engaging portion and a lowering portion, the lowering portion selectively actuatable to lower the upper stack-engaging portion to engage an upper surface of the stack.

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates to a conveyor system. More particularly, the present invention relates to a conveyor system for use in accepting one or more product streams and formatting the product to match the format required at the input of a packaging machine. 
     BACKGROUND OF THE INVENTION 
     Conveyor systems are used for a wide range of purposes. One such purpose is the formatting of one or more streams of product so that, for example, the product spacing corresponds to the spacing needed for a subsequent operation. Such conveyor systems are used, for example, to convert one or two output streams of stacked or shingled meat from a slicing machine into the format required by a packaging machine. Depending on the required format, the conveyor must combine two or more separate streams into a single output stream or multiply the streams into a larger number of output streams. Additionally, the conveyor must properly space the product along both the length and the width of the conveyor to ensure compatibility with the packaging machine. 
     Conventional conveyor systems for changing the number of streams of product usually include a simple flat belt conveyor and a series of fixed curbs or belt conveyors which guide the products in the lateral direction of the belt conveyor to merge two streams into one or to multiply the number of streams. Examples of these conventional conveying systems are described in FR-A-2587007, FR-A2168967, and U.S. Pat. No. 5,810,149. 
     U.S. Pat. No. 5,810,149 discloses a conveyor system for accepting one or more streams of product input and converting the one or more streams to a format that is suitable for automatic loading to a subsequent machine. To perform the format conversion some stacks must be temporarily stopped on a moving format conveyor to align lateral rows. The stopping is accomplished by bottom “pop up” stop grids that raise moving stacks from the conveying surface. The A•180® AUTOLOADER™, available from Formax, Inc., of Mokena, Ill., U.S.A. incorporates such stop grids. 
     While the system described in U.S. Pat. No. 5,810,149 and the A•180® AUTOLOADER™ have achieved success in the formatting of shingled stacks and straight stacks, the present inventors have recognized that frozen, near frozen or otherwise slippery slices of meat or cheese arranged in stacks tend to become disrupted when stopped from force on the bottom slice only by the bottom stop grids. 
     A typical A•180® AUTOLOADER™ employs the “pop up” stop grids that stop products received from the upstream slicer, in defined rows. The A•180® AUTOLOADER™ can have two or three rows to match packaging machine die formats. The products are typically traveling along the conveyor from 100 to 130 feet per minute when abruptly stopped by the pop up stop grids, triggered by photo eye sensors. Straight stacks of slippery slices tend to at least partially overturn or shuffle due to the inertia of the moving stack and the low coefficient of friction between slices.  FIG. 8  illustrates this phenomenon. Stacks that are out of proper alignment can be more difficult to package and can lose an orderly packaged appearance. 
     The present inventors have recognized the desirability of providing a stack stopping device for a formatting conveyor wherein stacks can be stopped on the conveyor without disturbing stack alignment. 
     The present inventors have recognized the desirability of providing a product stopping device for a conveyor wherein a quick and complete stop of the product can be ensured. 
     BRIEF SUMMARY OF THE INVENTION 
     An improved stack stopping mechanism is disclosed for a conveyor system that accepts one or more streams of product input and converts the one or more streams to a format that is suitable for automatic loading to a subsequent machine, the converting involving a step wherein stacks of slices must be temporarily stopped on a moving conveyor. 
     The stopping mechanism according to the invention includes a lower stop having a lower stack-engaging portion and a lift portion, the lift portion selectively actuatable to elevate the lower stack-engaging portion to engage a bottom surface of the stack and to lift the stack above the conveying surface, and an upper stop having an upper stack-engaging portion and a lowering portion, the lowering portion selectively actuatable to lower the upper stack-engaging portion to engage an upper surface of the stack substantially simultaneously with the lifting of the stack. The stack is thereby pressed between the lower stack-engaging portion and the upper stack-engaging portion to prevent shuffling or tipping of the stack during stopping of the stack. 
     The stopping mechanism can include a lost-motion connection between the lowering portion and the upper stack-engaging portion to accommodate stacks of varying heights. 
     The upper stack-engaging portion can engage the stack by force of the weight of the upper-engaging portion. 
     The lift portion and the lowering portion can be configured to act simultaneously. 
     The lift portion and the lowering portion can each comprise a pneumatic cylinder, the pneumatic cylinders being dual acting to both lift and lower the upper stack-engaging portion and the lower stack-engaging portion to engage and then release the stack. 
     The upper stack-engaging portion can comprise a disk having a flat bottom surface. 
     The lowering portion can comprise a pneumatic cylinder having an extending rod, and the lost-motion connection can comprise an end cap fixed to the rod and a connection portion fixed to the upper stack-engaging portion. The connection portion can have a space allowing limited free vertical movement of the end cap. 
     The invention provides a conveyor system for laterally aligning stacks of food products, comprising: a conveying surface receiving a stream of stacks sequentially in laterally spaced positions, the conveying surface conveying the stacks in longitudinal lanes; two lower stops arranged laterally side-by-side beneath two adjacent longitudinal lanes, and each having a lower stack-engaging portion a lift portion, the lift portion selectively actuatable to elevate the lower stack-engaging portion to engage a bottom surface of the stack and to lift the stack above the conveying surface; and two upper stops arranged respectively above the two lower stops, and each having an upper stack-engaging portion and a lowering portion, the lowering portion selectively actuatable to lower the upper stack-engaging portion to engage an upper surface of the stack, substantially simultaneously with the lifting of the stack; wherein when two side-by-side stacks are stopped by the two upper stops and the two lower stops, the two upper stops and the two lower stops are reversed to release the stacks to transfer the stacks together longitudinally along the conveying surface. 
     The present invention provides a product stopping device, the product being a single product, a shingled stack, or a straight stack, for a conveyor wherein a quick and complete stop of the product is ensured. 
     Numerous other advantages and features of the present invention will be become readily apparent from the following detailed description of the invention and the embodiments thereof, and from the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagrammatic elevational view of a slicing and packaging system that incorporates the present invention; 
         FIG. 2  is an enlarged, fragmentary plan view of a portion of the system shown in  FIG. 1 ; 
         FIG. 3  is a sectional view taken generally along line  3 — 3  of  FIG. 2 ; 
         FIG. 4  is a sectional view taken generally along line  4 — 4  of  FIG. 2 ; 
         FIG. 5  is a sectional view taken generally along line  5 — 5  of  FIG. 4 ; 
         FIG. 6  is a sectional view taken generally along line  6 — 6  of  FIG. 5 ; 
         FIG. 7  is an enlarged, fragmentary sectional view taken from  FIG. 3 ; and 
         FIG. 8  is an enlarged, fragmentary sectional view of a prior art stop arrangement. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     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 embodiments illustrated. 
       FIG. 1  illustrates a slicing/conveying/packaging system, shown generally at  20  which utilizes a conveyor system, shown generally at  25 , constructed in accordance with one embodiment of the present invention. As shown, the system  20  comprises a slicing machine  30 , the conveyor system  25 , and a packaging machine  35 . The system can be as described in U.S. Pat. No. 5,810,149, herein incorporated by reference. For simplicity of description, the system described does not include multilevel conveyors such as described in U.S. Pat. No. 5,810,149. 
     The slicing machine  30  may be, for example, a high-speed slicing machine such as an S-180™ or FX180™ available from Formax, Inc., of Mokena, Ill., U.S.A. The packaging machine  35  may be, for example, a TIROMAT 3000 available from Tiromat or MULTIVAC R530, available from Multivac, Inc. of Kansas City, Mo., U.S.A. Although the preferred embodiment is described herein in a system including the packaging machine  35  and the slicing machine  30 , it will be recognized that the conveyor system  25  can be used in connection with other types of product supplies and product outputs. 
     The conveyor system  25  accepts one or more streams of product from the slicing machine  30  and arranges the products in the proper format for acceptance by the packaging machine  35 . Different packages require different product formats at the packaging machine input. 
     To achieve the proper product format, the conveyor system  25  utilizes a plurality of unique conveyor sections that cooperate with one another to provide a wide range of different product formats with the same basic conveyor system construction. In the illustrated embodiment of the conveyor system  25 , the unique conveyor sections comprise an input conveyor  40 , a strip conveyor  50 , a row staging conveyor  65 , and output conveyors  70 ,  72 . The conveyors are driven by a plurality of motors and actuators under the control of, for example, a programmable logic controller (PLC) or microcontroller based system. The motors, actuators, and control electronics are preferably disposed within a main housing  75 . More preferably, the main housing  75  is separated into upper and lower regions by a dividing wall which separates and protects the control electronics from the motors, etc. 
     In operation, the input conveyor  40  receives one or more streams of stacked sliced meat from the slicing machine  30  and transfers the one or more streams to the strip conveyor  50 . The strip conveyor  50  is disposed to receive the one or more product streams, in this embodiment, from the input conveyor  40  and is operable to selectively shift its far end  50   a  laterally to deliver the one or more product input streams to positions spaced-apart across the width of the row staging conveyor  65 . The mechanisms for laterally shifting the conveyor end  50   a  are explained in detail in U.S. Pat. No. 5,810,149 regarding either of the upper and lower shift conveyors (numbered  50 ,  55  in U.S. Pat. No. 5,810,149). 
     The row staging conveyor  65  illustrated in the present embodiment comprises at least one set of lower stop members  80  that engage a bottom face of the product stacks received from the conveyor  50  and at least one set of upper stop members  82  that engage a top face of the product stacks received from the conveyor  50 , to align the product stacks in one or more rows. In the illustrated embodiment, the row staging conveyor  65  includes two rows of stop members  80 ,  82  each row being aligned laterally across at least a portion of the width of the row staging conveyor  65 . 
       FIG. 3  sets forth one embodiment of the lower stop member  80 . Each stop member  80  is comprised of an actuator section  83  which is connected to drive a stop grid section  84  in the vertical direction designated by arrows  84   a . The actuator section  83  preferably comprises a linear pneumatic actuator. The stop grid sections  84  comprise a plurality of longitudinally extending blades  85  that extend through an upper support surface  86  of the conveyor and are aligned with the interstitial regions between conveyor bands  87 , a few of which are shown in fragmentary fashion in  FIGS. 2 and 3 . The actuator section  83  of each stop member  80  is operable to drive the blades  85  of the stop grid section  84  between a first position in which the top of the blades  85  are disposed at or below the top surface of the conveyor bands  87  and a second position in which the top of the blades  85  extend above the top surface of the conveyor bands  87 . 
     The stop members  80  and the installation and configuration as a module are as available commercially in the A 180®) AUTOLOADER™, available from Formax, Inc., of Mokena, Ill., U.S.A. and are described in more detail in U.S. Pat. No. 5,810,149, herein incorporated by reference. 
     The strip conveyor  50  directs first and second product stacks to their respective lateral positions on the row staging conveyor  65 . When the conveyor system  25  detects that the first product is present at a first stop  80 ,  82  the stop members  80 ,  82  corresponding to the lateral position of the first product stack are actuated to simultaneously lift the product from the conveyor bands  87  and press the top of the product stack. Similarly, when the conveyor system  25  detects that a second product stack is present at a laterally adjacent stop  80 ,  82  located in an adjacent longitudinal column, the stop members  80 ,  82  corresponding to the lateral position of the second product stack is actuated to lift the product stack from the conveyor bands  87 . Once the first and second products are longitudinally aligned in a row by their respective stop members  80 ,  82 , both sets of stop members  80 ,  82  concurrently release the first and second product stacks for transport to, for example, the first accumulator conveyor  70 . Since the accumulator conveyor  70  is driven by a servo motor, its motion may be accurately controlled to align subsequent rows of product longitudinally as needed by the packaging machine  35 . Such a longitudinal spacing operation may likewise be performed by the second accumulator conveyor  72 . 
     The aforementioned example describes a simple arrangement for aligning side-by-side stacks and then releasing the stacks in a row. More detailed explanation of formatting product stacks using two rows of stops is described in U.S. Pat. No. 5,810,149, herein incorporated by reference. Once a group of two or more product stacks are longitudinally aligned in one or more rows by their respective stop members  80 ,  82 , the stop members are actuated to concurrently release the products as a formatted row or rows for transport to, for example, the first accumulator conveyor  70 . As noted above, one or both of the accumulator conveyors  70  and  72  may be used to longitudinally space successive rows of formatted product. 
       FIGS. 2-7  illustrate the upper stops  82  located over the row staging conveyor  65 . The upper stops  82  each comprise a rectangular baseplate  90  that is supported above the conveyor bands  87  of the conveyor  65 . The arrow “A” in  FIG. 2  indicates the conveying direction. The baseplate  90  is supported by four posts  94  that are fastened to the baseplate  90  and to side frame members  96 ,  98  of the conveyor  65 . Five pneumatic dual acting cylinders  102  are mounted to the baseplate  90 . The cylinders  102  are spaced apart and correspond in lateral position to the desired longitudinal columns of the product stream. The cylinders  102  are also aligned in opposition to each of the lower stops  80 . 
     Each cylinder  102  includes a rod  106  that extends downward through the baseplate  90 . The rod is raised or lowered by the cylinder depending on the differential pneumatic pressure exerted on a piston within the cylinder (not shown) that is connected to the rod. An end cap  108 , having a diameter greater than the rod  106 , is fastened to an end of each rod  106 . 
     A circular disk  112  is operatively connected to each rod  106 . A connector  114  is fixed to each disk  112 . The connector includes a space  118  having a width slightly greater than a diameter of the end cap  108 , and an end hole  120  that is smaller than the diameter of the end cap and larger than the diameter of the rod  106 . The connector can include a hole  122  opposite the end hole  120  that has a diameter greater than the end cap  108  to allow for installation of the end cap  108  onto the rod  106 . The disk  112  can also have a hole (not shown) aligned with the hole  122  for the installation of the end cap if necessary. The space  118  provides for a vertical lost-motion connection between the disk  112  and the rod  106 . The connector  114  can be an inverted U-shaped yoke or a hollow cylinder. 
     The cylinders  102  are enclosed by a housing  130  that is fastened around its perimeter to the baseplate  90 . The housing  130  can include a perimeter groove and a resident o-ring  134  that seals the housing  130  to the baseplate  90 . The housing can be composed of plastic. 
     At one end of the housing  130  are a plurality of quick connect fittings  140  that provide a pneumatic connection manifold for each cylinder  102 . Each cylinder  102  includes two inlet/outlet quick connect fittings  142  that are connected by tubes  141  to corresponding ones of the fittings  140 . For clarity of description, only two tubes  141  are shown schematically in FIG.  4 . The fittings  140  are in turn connected to pneumatic tubes  143  that serve alternately as pressurized air feed or air discharge for the cylinders  102 , the charging of the pneumatic tubes or the discharge of the pneumatic tubes is coordinated with the sensing of product stacks by the machine control as described in U.S. Pat. No. 5,810,149, herein incorporated by reference. 
     In operation, each upper stop  82  is actuated at substantially the same time as a respective lower stop  80 . In that regard, pneumatic tubes  143  for each upper stop  82  can be branched from the corresponding pneumatic tube that serves the opposing (through the belts  87 ) lower stop  80 . Alternatively, if more precise synchronizing between the actuation of the upper and lower stops is required, independent pneumatic actuation between upper and lower stops can be coordinated by the machine controller. 
     According to the invention, when the upper stop  82  is activated to descend onto a product stack, the rod is lowered a preselected amount corresponding to a maximum stack height (as shown in the left side of FIG.  7 ). However, if the stack height is lower, the lost motion provided by the space  118  allows the disk  112  to fall lower than the position shown in the left side of  FIG. 7 , with the end cap  108  traveling upward relatively within the space  118 . The disk moves downward by gravity, due to the wafer disk  112 . However, is also possible, and within the scope of the invention, that a spring can be used in the connector below the end cap  108  to urge the disk  112  downward with respect to the rod  106 . 
     The disk  112  is preferably a 3 inch diameter by ⅜ inch thick disk. The disk  112  and the attached connector  114  weigh about 1 pound. A one pound force is sufficient to hold the stack during stack stopping without unduly compressing the stack. 
     The right side of  FIG. 7  illustrates the disk  112  in its elevated position, before the cylinder  102  is actuated to lower the disk  112 . The stroke of the rod  106  by the cylinder between the two positions shown in  FIG. 7  is about ¾ inch. 
     Alternately, the pneumatic cylinders  102  of the stop members  82  may be replaced by linear drive mechanisms that are actuated by electrical control signals. In such instances, the connectors  140  and  142  would be electrical connectors and the supply lines  141 ,  143  would be electrical conductors. 
     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.