Patent GB-765887-A (GB)
Title: Box-stacking mechanism
IPC: B65G57/00
Filed: 1954-09-01
Abstract: 765,887. Conveying and stacking boxes. POMONA FOUNDRY, Inc. Sept. 1, 1954 [May 12, 1954], No. 25412/54. Class 78 (1). Boxes are continuously stacked by means including a vertical pathway, means feeding articles to a point along the pathway, and a box-moving means adapted to move the boxes in spaced relation upwardly or downwardly along the pathway to accumulate a predetermined number and thereafter to move the boxes downwardly on to a horizontal discharge conveyer to form a stack on the latter for discharge from the machine. As shown, the boxmoving means consists of opposed pairs of endless chains 80, Fig. 3, each pair carrying a series of pivoted supports 110. Each member 110 is formed by members 111, Fig. 5, carried by extensions 112 of link pins of the two chains of a pair and a sheet-metal member 114 extending transversely between members 111 to form a boxsupporting surface 115 and an inclined surface 116 adapted to engage the top of a previously stacked box 22 to cause the support to be pivoted out of the way so that the box carried thereby is deposited on the previously stacked box. Pivoting of support 110 is limited by stops 118, 120 in co-operation with a member 119 on the chain. In one embodiment the boxes are moved upwardly to accumulate the predetermined number. The boxes are fed in succession by a pair of endless chains 23 past a spring- loaded guide 29, Fig. 11, which directs them in turn against a stop shoulder 32, at the same time closing a switch 160, Fig. 4. Then, provided a switch 163 is not also actuated by a previous box being transferred to the supports 110, and provided the chains 80 are not being driven downwardly to form a stack, an electromagnetic valve is actuated to supply fluid to a cylinder 33 whose piston is adapted to push the box from the shoulder 32 whereby it passes to a pair of transfer chains 40 carrying pushers 47. Driving motor 68 for the chains 40 is energized when the box reaches a switch 165 and the box is pushed by pushers 47 against a projection 51 on a sliding bar 49 so that the latter is extended into the paths of the supports 110 against the restoring force of a spring 57. As bar 49 becomes fully extended a projection 166 on it actuates a switch 168 energizing reversible motor 104 for driving the chains 80 upwardly whereby the box is picked up by the supports 110 and carried upwards to a height greater than its own height, at which the next lower pair of supports 110 is just below the feed point, the extension 112 carrying one of these supports being adapted to engage a switch arm 172 deenergizing motor 104. As the box was picked up from bar 49 the latter was retracted by the spring 57. Motor 68 was de-energized by one of the pushers 47 actuating a switch 171. The above process is continued until a stack of predetermined height is formed, the height being selected by energizing the desired one of a number of switches 177 actuated by an extra long extension 112 on one link-pin of a chain 80 engaging an actuating arm 175, this causing motor 104 to be reversed and de-energizing switch 160 to prevent further feeding of boxes to the supports 110. Simultaneously with reversal of motor 104, fluid is caused to be supplied to a cylinder 146, Fig. 3, adapted to simultaneously raise a pair of opposed guide members 135 carried by parallel links 137 so that these members are pressed against the sides of the boxes to align them as they are lowered to form a stack. The stack is formed on a pair of normally stationary endless chains 125 supported in guides 129, the supports 110 pivoting upwardly and outwardly from between the boxes as each box is brought to rest on a lower box. After the stack is formed chains 80 continue to move downwardly until an element 186 on one chain contacts actuating arm 187 of a switch 189 which de-energizes motor 104 and exhausts the cylinder 146. When the bottom box was first deposited on chains 125 it depressed actuating arm 183 of a switch 184 operating a delay relay timed to cause chains 125 to be driven for a selected distance after chains 80 have stopped to remove the stack, after which switch 160 is re-energized to allow further feeding of boxes to accumulate a fresh supply for a further stack. If the operator failed to select one of the switches 177 for limiting the height of the stack, the chains 80 are stopped in their upward direction by contact of the top box with a spring-loaded bar 180 actuating a switch 178 for de-energizing motor 104. In a modification, the bar 49 may be actuated by a double-acting fluid-pressure cylinder. In a further modification, Fig. 14, the boxes are accumulated by downward movement of chains 80, the boxes being fed to the supports 110 at the top end of the pathway from endless chains 230 by a carrier bar 231 reciprocated in an orbital movement by a pivoted fluid-pressure cylinder 204, whose piston-rod 205 is connected to the forward end of the bar, the bar being guided in the orbital path by pins 232 on the bar engaging guide channels 234 each having a pivoted non-return flap 236 at the entrance to its lower section 245.