Patent GB-787257-A (GB)
Title: Apparatus for lifting stacks of sheets or the like to facilitate the formation of overlapping stacks on a support
IPC: B65H33/08
Filed: 1954-12-07
Abstract: 787,257. Feeding sheets. HOLSCHER, F., and WINDMOLLER, A., [trading as WINDMOLLER & HOLSCHER.]. Dec. 7, 1954 [Dec. 9, 1953; Aug. 11, 1954; Nov. 22, 1954], No. 35378/54. Class 100(1) In apparatus for feeding flattened tubular work-pieces of paper to a machine, e.g. for making block-bottom bags, wherein individual stacks of these work-pieces are arranged upon a feed table and the rear edge of each stack is to overlap the leading edge of the succeeding stack, manually-, foot-, or power-operated appliances are provided which raise the rear edge of each stack in succession. As shown in Fig. 1, small stacks 2, 3, 4 are disposed on a feed table 1, and a suction or other separator 5 separates the individual pieces 8 from the front stack 2 and feeds them between feed rollers 6, 7. When all the pieces of the stack 2 have been fed, conveyer belts (not shown) feed the stacks forward until the stack 3 is adjacent the rollers 6, 7, the rear end of the stack 4 is lifted, and the front end of another stack is placed beneath. The means for raising the stack 4 comprises a number of rods 9 secured to a shaft 10 pivoted in carriages 11 adapted to slide along fixed guides 12. Each carriage 11 is secured to an endless chain 14 passing over wheels 15, 16. The shaft 17 of the wheels 15 is geared to electromagnetic clutches 21, 22 which can be engaged with driving means so that the shaft 17 can be driven in either direction depending upon the manual operation of switches. Secured to the shaft 10 is a quadrant rack 30 engaged by a similar rack 31 which forms part of a bell-crank lever pivoted on the same carriage 11, the other arm 32 of this bell-crank having a roller 33 urged by a spring 34 into contact with a rail 35. The rail 35 is pivotally supported for parallel vertical movement by bell-crank levers 38, 39 and 40, 41, pivoted about fixed pivots 42, 43, respectively, these levers being joined together by a rod 44. The rod 44 can be moved to the left by an electromagnet 45, again.st the action of a return spring 46, to raise the rail 35 which, through the roller 33 and racks 31, 30, swing the rods 9 upwardly. The rods 9 can pass through slots in the table 1 to engage and lift the rear end of the stack 4. The electric circuit includes two switches which are operated automatically, one switch 26 is opened when the rods 9 rise, and a feeler 29 engages the stack 4, and another switch 24 which is closed when the carriages 11 move to the right due to a roller 27 engaging a cam 28 on one carriage. In operation, when all the sheets of the stack 2 has been fed and the stacks 3, 4 have been moved by the conveyer belts towards the rollers 6, 7, the operator actuates switches, by means such as a foot-pedal, whereby the electromagnet 45 is energized and the rods 9 are swung upwardly, and the clutch 22 is thrown in to drive the chain 14 and carriages 11 to the right. The rods 9 therefore lift up the rear end of the stack 4, the feeder 29 is depressed to open the switch 26, and the clutch 22 is thereby released so that the carriages 11 stop, after a small further movement due to the momentum of the system. The operator now slides a new stack below the raised end of the stack 4, operates switches, for example by releasing the foot-pedal, to de-energize the electromagnet 45, and this causes the switch 26 to be closed, the clutch 21 to be energized, and thereby the chain and carriages are moved to the left until the switch 24, is automatically opened. Modifications in the electric circuit can be made, whereby a new stack may initiate the operation of the apparatus. In the form shown in Fig. 7, rods 80 are pivoted on a bar 81 having rollers mounted in end guides 83, 84 of U-shape. Links 87, 88 connect the bar 81 to levers 89, 90 secured on a shaft 92, and a sprocket segment 93 secured to the shaft is engaged by a chain 94 secured to one end of a foot-operated bell-crank lever 95. On depression of the pedal 97, the levers 89, 90 are swung to the right, against the action of a return spring 98, and the bar 81 is moved along the end guides 83, 84 carrying the rods 80 which lift up the rear end of the stack 4. The ends of the rods 80 slide in grooves 64 in the table 1. In further forms, which are modifications of Fig. 7, the pedal-operated bellcrank lever acts through a system of levers instead of a chain and sprocket gear. The bell-crank lever could be operated electromagnetically.