Method and apparatus for buffering a flow of objects

Abstract

A buffer device for buffering a flow of stacks of discrete objects between a stacking machine and a packaging machine is disclosed which buffer includes a plurality of individual trays mounted on carriers which carriers are mounted on a frame and driven about the periphery of the frame by a drive. A first number of stacks of objects is placed on a first number of carriers on a first side of the frame and a second number of stacks are removed from a second number of carriers on a second side of the frame where the first number can be greater than, less than or equal to the first number. The carriers clamp onto a continuously moving drive belt in a manner that allow the drive belt to slip through the carrier clamps when motion of the carriers is obstructed. A method of using the buffer device is also disclosed.

1 . A method for buffering a flow of stacks of objects from a first location presenting a first number of stacks to a second location adapted to receive a second number of stacks comprising the steps of: 
 providing a frame between a first location and a second location having a first position and a second position;    providing a plurality of carriers each adapted to hold a single stack;    associating the carriers with the frame;    moving the first number of carriers to the first position;    simultaneously moving the first number of stacks from the first location to the first number of carriers at the first position thereby filling the first number of carriers;    moving the first number of filled carriers at the first position toward the second position;    whenever at least a second number of filled carriers are present at the second location, moving simultaneously the stacks from the second number of filled carriers at the second position to the second location; and    returning empty carriers from the second position toward the first position.    
   
   
       2 . The method of  claim 1  wherein the step of moving simultaneously the stacks from said second number of filled carriers at said second position to said second location comprises the step of moving said second number of filled carriers at said second position to said second location more often than said first number of stacks are moved from said first location to said first position.  
   
   
       3 . The method of  claim 2  including the additional step of providing a first stop at said first location shiftable between blocking and non-blocking positions, wherein carriers are prevented from moving past said first stop when said first stop is in said blocking position.  
   
   
       4 . The method of  claim 3  including the additional step of providing a second stop at said second location shiftable between blocking and non-blocking positions, wherein carriers are prevented from moving past said second stop when said second stop is in said blocking position.  
   
   
       5 . The method of  claim 4  wherein the step of providing a frame between said first location and said second location comprises the step of providing a frame having a top wall having a periphery and a guide rail extending around said periphery.  
   
   
       6 . The method of  claim 5  wherein the step of providing a plurality of carriers comprises the step of providing carriers having a guide wheel and wherein the step of associating said carriers with said frame comprises the step of engaging said carrier guide wheel with said guide rail.  
   
   
       7 . The method of  claim 3  including the additional step of providing at least one sensor for detecting the presence of a carrier at a point on said frame.  
   
   
       8 . The method of  claim 7  wherein the step of providing at least one sensor for detecting the presence of a carrier at a first point on said frame comprises the step of providing a first sensor for detecting the presence of a carrier at a first point on said frame and detecting the presence of objects on said carrier.  
   
   
       9 . The method of  claim 8  including the additional step of providing a second sensor for detecting the presence of a carrier at a second point on said frame.  
   
   
       10 . The method of  claim 1  wherein the step of releasing empty carriers from the second position comprises the step of releasing said second number of carriers from said second location.  
   
   
       11 . The method of  claim 8  including the additional step of shifting said first stop to said blocking position when said first sensor detects an empty carrier at said first position.  
   
   
       12 . The method of  claim 11  including the additional step of moving said first stop to said non-blocking position when said first sensor detects a full carrier at said first position.  
   
   
       13 . The method of  claim 11  including the additional step of moving said second stop to said blocking position when said second sensor detects a full carrier at said second position.  
   
   
       14 . The method of  claim 13  including the additional step of moving said second stop to said non-blocking position when said second sensor detects an empty carrier at said second position.  
   
   
       15 - 33 . (canceled)  
   
   
       34 . A method of receiving a first number of stacks of discrete objects from a stacking machine and presenting a second number of the received stacks for removal by a stack transfer machine comprising the steps of: 
 providing a frame having a periphery and a first location and a second location;    providing a drive on said frame;    providing a plurality of carriers adapted to hold a single stack;    mounting said carriers on said frame;    connecting each of said plurality of carriers to said drive;    providing a first sensor for counting the number of carriers passing a first point;    providing a second sensor for counting the number of carriers passing a second point;    providing a first stop near said first point for preventing carriers from passing said first stop;    receiving the first number of stacks in each of said first number of carriers at said first location;    releasing the first number of carriers from said first stop;    providing a second stop near said second point for preventing carriers from passing said second stop;    removing said second number of stacks from said first number of carriers at said second location; and    releasing the second number of carriers from said second stop.    
   
   
       35 - 43 . (canceled)  
   
   
       44 . A carrier comprising a trolley adapted to support a tray for holding stacks of objects, said trolley comprising: 
 a body having a first side and a second side and including a first wall portion having an end and a second wall portion extending from the end of said first wall portion at an obtuse angle;    an axle extending from the first side of said second wall portion;    a wheel rotatably supported by said second wall portion axle; and    a clamp mounted on the first side of said first wall portion.    
   
   
       45 . The carrier of  claim 44  wherein said wheel includes a circumferential groove.  
   
   
       46 . The carrier of  claim 44  wherein said clamp comprises first and second relatively adjustable spaced members.  
   
   
       47 . The carrier of  claim 44  including at least one second wheel connected to said first wall portion and supported for rotation about an axis substantially parallel to said first wall portion.  
   
   
       48 . The carrier of  claim 47  including at least one third wheel connected to said first wall portion and supported for rotation about an axis substantially perpendicular to said first wall portion.  
   
   
       49 . The carrier of  claim 47  including at least one fourth wheel connected to said first wall portion and supported for rotation about an axis substantially parallel to said first wall portion, wherein the axis of said at least one fourth wheel extends between the axis of said at least one second wheel and said first wall portion.  
   
   
       50 . The carrier of  claim 48  wherein said at least one third wheel comprises a pair of wheels.  
   
   
       51 . The carrier of  claim 49  wherein said at least one fourth wheel comprises a pair of wheels.  
   
   
       52 . The carrier of  claim 44  including a projection on the second side of said body for supporting a tray.