GB1027466A - Improvements in or relating to sheet feeding mechanism - Google Patents

Abstract

1,027,466. Feeding sheets. KOPPERS CO. Inc. March 13, 1964 [March 13, 1963], No. 10854/64. Heading B6B. Sheets are separated sequentially from the bottom of a pile by a suction belt which travels at non-uniform speed during each sheet separation. The belt is moved bodily towards and away from the sheet pile, and is accelerated from rest to the speed of forwarding rollers which convey the sheets to a printing &c. machine. As shown, the sheet feeding apparatus comprises two endless belts 89 which have two separate sets of perforations therein, and pass over suction boxes which are interconnected and communicate with a continuously-operating suction pump. Each belt passes over front pulleys 71 secured to a driven crossshaft 69, and over rear pulleys 76 and a further set of pulleys 84, Fig. 3 (not shown), arranged below the pulleys 76, and the rear sets of pulleys and the suction box are carried by end plates 73 which are pivoted on the front shaft 69. Thus, both belts and their suction boxes can be swung simultaneously about the shaft 69. The belts are located in apertures in a table 13 which supports a pile of sheets 21. The sheet pile is registered by corner guides 24 and a centre guide 23 which are slidably mounted on a cross-bar 14, and a plate 22 is adjustable vertically on the guide 23 so that only one sheet can be separated at a time by the belts 89. The rear end of the framework, carrying the belts &c. is supported by a roller 99, Fig. 3, which rests on a cam 98 secured to a rotating shaft 103 beneath the table 13, whereby the belts are moved periodically towards and away from the bottom sheet in the pile: the roller 99 is one of a pair 99, 102 mounted on a carriage 119 which can be moved by rotating a knob 111, so that the second roller can be brought over a second cam 101 to modify the oscillations of the belts 89 when sheets longer than normal are being separated. To provide for the separation of shorter sheets than normal, the outer end plates 73 of the belt framework have rails 127 secured thereto, and a follower 106 on one rail engages a rotating cam 104 which modifies the raising of the belts 89. In addition, pads 132 are slidably received on the rails 127 to keep the rear end of the sheet pile away from the belts during the separation of the bottom sheet. The belts 89 are positively driven without slip by the pulleys 71, and the shaft 69 is coupled by gears 68, 67 to a shaft 64 which is driven at non- uniform speed from a shaft 54 through a cam 59 and follower means 61, or any known device, such that the belts during each sheet separation cycle are accelerated, moved at constant speed, decelerated, and then stopped for a short period. The shaft 54 is geared to the shaft of a feed roller 17, the other end of which is coupled by a belt and pulley means 36, 37 to a motor-driven pulley 34. The roller 17 is geared to an upper feed roller 16 which is mounted in eccentric bearings 32 adjustable by gearing operated by rotating a cross-shaft 29. The rail 14 is also secured to the eccentric bearings 32, so that when sheets of a different thickness are to be separated, it is only neces. sary to rotate the shaft 29 to adjust the roller 16 relatively to the roller 17, and the guides 23, 24 relative to the table 13. A specific example giving dimensions of belts, speeds of belts, feed rollers, printing cylinder, and length of sheets is described. The belts 89 are at rest when they are first brought into contact with the bottom sheet of the pile, are then accelerated to maximum speed, are then decelerated and lowered at the same time until they come to rest, and are then raised again for the next cycle.