Patent GB-797723-A (GB)
Title: Sheet feeding apparatus
IPC: B65H1/18
Filed: 1956-01-17
Abstract: 797,723. Feeding sheets. ROSBACK CO., F. P. Jan. 17, 1956 [Jan. 18, 1955], No. 1601/56. Class 100(1) In apparatus for separating sheets from the top of a pile which is raised automatically by a power-driven elevator under the control of a feeler device resting on the top of the pile, the elevator is driven through a pawl and ratchet device, and the pawl is controlled by a fluid control means conditioned by the feeler device. As shown, the apparatus feeds sheets to a sheet-perforating device 10 which drives a shaft 20 on the apparatus and a number of conveyer tapes by means of a belt 23. Sheets are separated from a stack 28 by a rotary suction roller 33 having a stationary suction box fitted thereagainst which is connected to a suction source through a valve 50 controlled by a :rod 81 actuated by a rotating crank disc 13 on the perforator 10. The roller 33 co-operates with a sheetguide to feed the sheets on to the conveyer tapes, and a single presser which is arranged above the shaft 20 about which the tapes pass. The roller 33 is driven by a belt passing around a split-cone variablespeed pulley, and means is provided for adjusting the pulley to vary the speed of the roller 33 in the case of overlapping feeding to the tapes 21. Pile-raising means. The stack 28, is supported on a platform 27 resting on a pair of brackets 31 attached to the ends of chains 32 which pass over drive sprocket wheels 53. These sprockets 53 are driven from a shaft 57 through worm and wormwheel gearing. The shaft 57 can be rotated by a hand-crank to adjust the platform 27 initially, or for lowering it to receive a new pile; but for power operation, it has secured thereto a ratchet-wheel 60, Fig. 4, adapted to be engaged by a pawl 62 pivoted at 63 in cheeks 64 which support an air cylinder 66. There are two plungers 67, 70 in this cylinder, each with an end collar to limit movement into the cylinder, the top plunger 67, when raised, engaging an arm 65 on the pawl 62 to cause the latter to engage the teeth of the ratchet 60. The bottom plunger 70 is constantly reciprocated by the rod 81, which is actuated by the crank disc 13 on the perforator 10, acting through a bell-crank 76. The air space 72 between the plungers communicates through a fitting 107 and pipe 106 with a valve of the bicycle type associated with a feeler device 98 resting on the top of the stack 28, and when the stack is below the correct height this valve is closed. In this condition, when the plunger 70 is reciprocated, first the upper plunger 67 is raised by the air compressed at 72 to engage the pawl and ratchet, and then the collar 71 engages the cylinder to raise it positively so that the shaft 57 is rotated to raise the stack 28. If, however, the feeler is raised sufficiently by the stack, a needle enters the bicycle valve and opens it, so that there is no air cushion at 72, the top plunger 67 is not raised, and the cylinder 66 is merely reciprocated idly. The feeler device 98 is on an arm 97 pivoted on a vertical rod rotatably adjustable in a mounting 90 slidable along a rod 98 which is pivoted about a vertical post 87, so that the feeler has a wide range of adjustability. The apparatus can be readily modified so that the feeler 98 controls the gradual lowering of the platform 27 to receive sheets delivered thereon from a machine.