GB707044A - Improvements relating to the separation of sheets of paper or the like from the top of a pile - Google Patents

Abstract

707,044. Feeding sheets. BACKHOUSE, H. T. May 9, 1951 [May 10, 1950], No. 11692/50. Class 100 (1) Sheet-separators.-Relates to a sheet-separator of the kind wherein a suction head 18 is lowered on to the uppermost sheet in a pile, and is elevated by the suction created in a cylinder 5 due to the closing of the suction grippers 19 by the sheet, the lifted sheet being then traversed laterally to a discharge point where the suction is destroyed by the opening of a valve 30, as is described in Specification 674,843. According to the invention, the suction head is lowered by a cam-actuated pivoted lever 10, 12, to which the piston rod is pivoted at an intermediate point, whereby, after seizing the sheet, the head is elevated pneumatically more rapidly than it is lowered mechanically. The device is mounted on tubular cross-bars 2, 3 above a pile 1 and comprises a housing 4 in which are journalled a shaft 11 forming a pivot for the bell-crank lever 10, 12 and a driven shaft 15 carrying cams 14 (not shown), 39 and 67. The arm 10 of the lever is bifurcated and carries at one end a parallellink structure 16, 17, supporting the suction-head 18, the piston rod 7 being pivoted between the bifurcated parts in a cross-head 8. The arm 12 of the bell-crank carries a roller 13 engaging a cam 14 (not shown) on the shaft 15, to lower the head slowly. The lateral movement of the head 18 is derived from a cam 39 engaging a roller 38 on an arm 36 connected to the parallel links 16, 17. A further cam 67 controls the raising of parallel links 60, 61 carrying a presserfoot 62. and air-blast nozzles 63. Spring-blades 50 depend from a fixed part of the housing. The operation is as follows: the cam 67 raises the foot 62 and the nozzles 63 emit an air-blast to fluff up the edges of the pile; the head 18 is lowered slowly and seizes the fluffed-up top sheet in mid-air, retracting, immediately under the action of the piston 6, so that the sheet is bent by. contact with the blades 50 ; a stop 32 then contacts the valve 30 to cut off the suckers 19 from the cylinder 5 and a further blast is directed below-the top sheet to separate adherent lower sheets ; the cam 67 then lowers the foot 62 to clamp the remaining sheets and the cam 39 moves the head 18 laterally until contact between a stop 31 and the valve 30 opens the system to the atmosphere, permitting the release of the sheet. During the subsequent return of the head the slide-valve 30 again moves to open the cylinder 5 to the atmosphere and permit the fall of the piston. Specifications 674,888, 692,034, and 707,043 also are referred to.