Patent GB-1210745-A (GB)
Title: Pallet stacking apparatus
Inventor: GEORGE EDGAR
IPC: B65G57/30
Filed: 1968-10-11
Abstract: 1,210,745. Stacking machines. FMC CORP. 11 Oct., 1968 [12 Oct., 1967], No. 48262/68. Heading B8C. A stacking machine for building up a stack of pallets from the bottom comprises laterally adjustable, parallel pallet guide members 34 mounted on a frame structure 50-59, endless conveyers 36 mounted on the guide members and continuously driven by hydraulic motors M2, M3 conveying pallets into the machine, a lift 40 positioned between the conveyers to raise a pallet upwardly therefrom, a plurality of palletsupporting dogs 42 pivotally mounted on the guide members and urged inwardly by springs 135 so that individual pallets may be each raised past the dogs and subsequently supported thereon on lowering of the lift to form a stack, and a mechanism mounted on the guide members for holding the dogs outwardly against the bias of the springs to permit a completed stack to be lowered by the lift past the dogs to the conveyers for removal from the machine. The said mechanism comprises a rotatable shaft 126 supported along the length of each guide member along which shafts the dogs are adjustably fixed to accommodate various pallet lengths, a camplate 142 secured to each shaft, and an hydraulic actuator 140 for rotating each shaft to move the dogs outwardly to an inoperative position. On entry of a pallet into the machine, the conveyers carry it against longitudinally - adjustable, hydraulically - operated exit stops 38 pivoted to the guide members. The pallet closes a first switch LS-1 which actuates a first hydraulic cylinder 43 to raise the lift and a second hydraulic cylinder 160 which raises a pivotal entry stop 43 to block the entry of a further pallet. On raising the lift, which comprises a platform mounted on pairs of crossed levers 90, 96 having a scissors action, an end of one lever successively trips a second switch LS-4 to operate a counter, Fig. 15 (not shown), recording the number of pallets stacked and a third switch LS-2 for stopping upward movement of the lift after the pallet has been carried past the dogs. The lift falls under gravity, the dogs retaining the pallet, and actuates a fourth switch LS-3 to retract the entry stop so permitting another pallet to enter the machine. The cycle is repeated until the number of stacked pallets reaches the desired quantity whereupon the counter functions, through various relays, solenoids and valves of electric and hydraulic machine control system, Figs. 14 and 15 (not shown), as the last pallet of the stack is raised to actuate cylinders 140 to move the dogs to the inoperative position and cylinders 182 to pivotally lower the exit stops 38 below the conveyers. The stack is then lowered by the lift on to the conveyers and removed from the machine. As the stack leaves the machine, it closes a switch LS-6 to re-energize the counter and depressurize cylinders 140, 182 to permit the dogs and exit stops to return to their operative positions for the next stacking cycle. The guide members may be laterally adjusted whilst the machine is in operation by operation of motor M4 which rotates shafts 190, 192 threadedly connected to each guide member by oppositely handed threads at each shaft end.