Patent GB-827952-A (GB)
Title: Improvements in sheet separating and forwarding machines
Inventor: BACKHOUSE HEADLEY TOWNSEND
IPC: B65H3/40
Filed: 1954-09-01
Abstract: 827,952. Feeding sheets. BACKHOUSE, H. T. Dec. 1, 1955 [Sept. 1, 1954; Oct. 28, 1954; Dec. 8, 1954], Nos. 25428/54, 31198/54 and 35615/54. Class 100(1) Sheet separator:-In apparatus of the kind in which an edge or a corner portion of the rear of each uppermost sheet of a pile is first lifted from the pile by one or more grippers and transferred directly or indirectly to forwarding grippers which move substantially in the plane of the sheet to forward the sheet over the pile, two separating suction grippers (or two sets of such grippers) are provided which operate on alternate sheets respectively to lift the edge or corner portions thereof. As shown applied to a stream-feeder; there are two sets of separating and lifting suction grippers 10 and 11 which operate alternately near the centre of the back of the pile of sheets. Each set, as shown in Fig. 3, first descends along a vertical path 100, rises gripping a sheet 104, along the path 100, 101, releases the sheet to forwarding grippers 14, then moves rearwardly and downwardly along the paths 102, 103, and finally moves inwardly to the top of the path 100. Each gripper 10, 11 is carried by a telescopic arm 40, 47 operated to swing to-and-from the pile by a cam on a shaft 29 mounted in fixed frames 22, and the vertical movements are performed by a second cam which rocks a bell-crank, such as 53, connected to a sleeve 50 on the part 40 of the telescopic arm which carries the gripper. Each gripper 10, 11 is of the collapsing type which effects an initial lift when the mouth of the sucker is sealed by a sheet. The parts 40, 47 of each telescopic arm of a sucker are urged apart axially by a spring. A presser foot 15 is arranged to move inwardly to press on the pile whilst the top sheet is being lifted, and an extension of the cam-operated bellcrank arm which actuates this foot is so coupled with the airblast fluffing nozzles 16 that, as the pile is depleted, the nozzles are also lowered correspondingly and are therefor always at the correct height. When a sheet is lifted, separation is assisted by air-blasts from a nozzle 17 which is given up and down movements controlled by a cam on the shaft 29. Rods 110 slidable in fixed guides 111 rest on the pile to limit the fluffing-up of the sheets. There may be two sheet-separating air-blast nozzles 17 arranged for operation beneath alternate sheets, respectively, and for a short period in each cycle the two nozzles may be blowing at the same time: also there may be two presser feet 15 which alternate with one another, and two fluffing air-blast nozzles 16 which act alternately. Assuming that in the arrangement described above using one presser foot 15, one set of nozzles 16, and one nozzle 17, the complete separation of a sheet by the suckers represents one complete revolution of a part of the apparatus which rotates uniformly for each sheet separated, there may be allowed 270 degrees for fluffing of the sheets and initial separating collapse of the suckers 10 or 11; 180 degrees for the lifting of the suckers above the pile; 110 degrees for the dwell of the suckers; 270 degrees for the return movements of the suckers; 150 degrees for the forwarding of the sheet; and 250 degrees for the separating air-blast 17. Specifications 774,874, 774,875 and 774,876 are referred to.