Patent GB-797731-A (GB)
Title: Improvements in or relating to sheet feeding apparatus
IPC: B65H3/12
Filed: 1955-09-13
Abstract: 797,731. Feeding sheets. LABOMBARD, R. A. Sept. 13, 1955 [Dec. 16, 1954], No. 26162/55. Class 100(1) Sheets are successively slidingly separated from the bottom of a pile by suction cups each having a flat friction face of substantial area and movable in a substantially unidirectional rectangular path, the front of the pile being contained by a cam-aperated gate which will permit sheets to be separated of a length greater than the normal length usually permissible. As shown, a pile 25 of box blanks 24 rests on a number of fixed support bars 40 provided with rollers 41, the pile being confined at the sides by guide plates ,and the front abuts a gate 30 which is adjustable vertically to allow the separation of only one blank at a time. In cases where the blanks are longer than ordinary and have not been cleared away from the gate 30 before the next blank is acted upon by the separator means, cams 134, Fig. 5, can be slid along a shaft 132 to operate on links to lift the gate vertically to allow a second blank to pass. The separator means comprise five suction cups 65, with flat rims 71 of rubber or other material having a high coefficient of friction, arranged to move in a substantially rectangular path. Each sucker 65 is connected by flexible tubing to a rotary valve 68 mounted on a shaft 104 which also actuates the movements of the suckers. The suckers are each carried by a bar 85 adjustably secured in a collar 82 which is adjustably secured on a cross shaft 81 mounted in end plates 75, 76. Rollers on the plates 75, 76 are guided for rolling along tracks 79, 80 secured on vertical rods 89 which are each adapted to be reciprocated by means of a cam on the shaft 104, acting through a lever 106 and link 110. Two other cams on the shaft 104 reciprocate the plates 75, 76 along the tracks 79, 80 by acting on rods 94 connected by links to the plates. The arrangement is such that the suckers 65 approach the bottom blank 24 perpendicularly to grasp it by friction and suction, then move to the right to carry the blank past the gate 30 to a position where it can be grasped by feed rollers 50, 51, and then move downwardly away from the blank and to the left to starting position. The feed rollers 50, 51 are both driven positively, the rollers 51 being plain, and the roller 50 having a raised toothed or corrugated surface 57, followed by a smooth surface 56, which is followed by a recessed surface 62. The teeth on the surface 57 grip and feed the blank, and the recessed surface 62 permits the leading edge of a blank to be advanced into the nip of the rollers. The blank is finally removed by conveyer belts or chains 60, 61. The driving arrangement includes a chain 140 which engages sprockets on cam shaft 132, feed roller shafts 55, 54, shaft 145, and shaft 148. The shaft 104 can be driven from the shaft 148 by gears 149, 150, or by gears 151, 152, whereby two speeds can be imparted thereto. When the gears 149, 150 are meshed, one blank 24 is separated by the suckers 65 for each two revolutions of the feed rollers 50, 51, and with the gears 151, 152 in mesh one blank is separated for each single revolution of the feed rollers. In each case, where blanks are above a certain length, the cams 134 are brought into use to operate the gate 30 to allow the trailing edge of one blank and the leading edge of the next blank to pass beneath the gate temporarily. As shown in Fig. 9, the suckers may be constructed to bow the blank to be separated away from the stack before the actual separation begins. Each sucker comprises a cup 165 having a suction face 190 surrounded by a friction rim 191, a collapsible bellows 192, and a tube 193 which is connected by a pipe 70 to a source of vacuum. The tube 193 and base of the bellows are secured on a bar 185 adjustably secured in a collar 82, which is itself adjustably secured on a transverse shaft 81 as before. An inverted U-shaped housing 186 carries the upper end of the bellows and the face 190, and is pivoted to the bar 185 so that it can be tilted against the action of a spring 188 to an extent limited by a stop screw 189. When the sucker is moved perpendicularly up to the bottom blank 194 and adheres thereto, the bellows 192 collapse, the housing 186 will tilt, and hence the blank 194 will be bowed downwardly away from the stack.