Patent GB-640529-A (GB)
Title: Improvements in automatic sheet feeding apparatus
IPC: B65H1/30
Filed: 1947-10-13
Abstract: 640,529. Feeding sheets. DEXTER FOLDER CO. Oct. 13, 1947, No. 27386. Convention date, Oct. 12, 1946. [Class 100 (i)] In a sheet-feeding device in which the sheets are fed automatically from the top of a vertical pile two pileelevating devices are provided and are arranged to co-operate to maintain a continuous pile of sheets automatically below the sheet separators without having to stop the feeder for re-loading. In the form shown in Figs. 1a and 2a, a pile of sheets 27 in active position is supported by spaced fingers 26 mounted in a carriage which can be moved laterally to withdraw the fingers 26 to permit a second pile 130 to be raised to engage the bottom of the pile 27 before this pile is exhausted. The carriage is formed of rack bars 33 movable in guides 35, and it is supported by a frame 38, 39 mounted on piston 43 which is raised and lowered hydraulically by liquid supplied by a pump 144 arranged above a tank 140 and fitted with a relief valve to limit the hydraulic pressure. The pile 130 is also supported hydraulically by a piston 133 and cylinder 136 supplied by the pump 144, and as shown the piston 39 is in raised position and the piston 133 in lowered position. Spaced fingers 129 carried by piston 133 are staggered relatively to the fingers 26. From the position shown, however, the piston 43 is advanced intermittently by valve mechanism under control of the height of the pile on which rests a roller 224 mounted in a pivoted arm 222 formed with an arm 223 adapted to operate a micro-switch 225 which opens a valve 'to admit more liquid to the cylinder 45 and thus raise the pile 27. When the fingers 26 reach the position shown by broken line A, Fig. 2a, a control arm 314, Fig. 1a, which moves with piston 43, engages a roller 313 on a trip-lever 309 and depresses a rod 302 which releases a latch from the position in which it holds a pushrod 280, Fig. 5a, in a raised position. On release of the rod 280 it engages the low part of a cam 283 and operates a valve 276, Fig. 5a, which directs the hydraulic pressure to the cylinder 136 which raises the piston 133 and advances the pile 130 rapidly. The top of pile 130 acts upon a control arm 103 pivoted to the main elevator 25 and counterclockwise movement of the arm actuates a micro-switch 106 which energizes an electromagnet 98, Fig. 1, and so releases a spring catch 91 which normally prevents a friction coupling from driving a crank disc 72. When released the crank disc 72 moves the carriage supporting the fingers 26 and withdraws the fingers 26 to the left out of engagement with the remaining sheets of pile 27. The catch 91 again acts on the friction coupling to arrest the motion of the crank disc after a half revolution of the friction coupling. The fingers 26 then occupy position B, Fig. 2a, and the pile is prevented from moving with the fingers 26 by means of rear pile guides 383. The diminished pile 27 is deposited on the new pile 130, and the intermittent raising of the pile 130 is effected by the cylinder 136 and piston 133, and then the piston 43 is lowered to bring the fingers 26 into position C, Fig. 2a. The transfer of pressure liquid from the cylinder 45 to cylinder 136 is effected by the operation of sliding valves which are actuated by cams on a shaft 206 which is rotated intermittently by a friction coupling which is controlled by a latch 340 released to permit a half revolution of the shaft 206 by a cam 361 on crank-disc 72 just before the fingers 26 reach position B. The cam 361 momentarily closes contacts 353, 354 of a switch 351 which energizes a magnet 350 to release the latch 340 and permit half a revolution of the cam-shaft 206. This causes pressure to be transferred from cylinder 45 to cylinder 136 and a new pile 130 is raised rapidly and brought into contact with the expiring pile. The fingers 26 are lowered to position C and then the friction coupling which drives the crank-disc 72 is released so that a further half revolution thereof moves the fingers 26 to the right to position E, from which position they are raised into contact with the replenished pile and the fingers 129 lowered into position to receive a further pile 130. The intermittent raising of the pile under control of the roller 224 takes place whether the pile is supported by the fingers 26 or 129. The piles of new sheets are fed on to the fingers 129 by a pair of conveyer chains 393 to which are pivoted a number of pushers 402 which move over slots in a table 384 which, as shown, supports two new piles 385 placed thereon by an unskilled operator, but more than two piles may be arranged at once on the conveyer. Each new pile is placed in correct position by the aid of registering devices 409, 410, Fig. 1, and the pushers 402 are formed with rearwardly-extending right-angle portions 403 in which are journalled rollers 404 adapted to move in tracks 389. Guides 417 act on the sides of the piles as they are moved towards the fingers 129, and the guides are adjustable for sheets of different widths. Strips 422, Fig. 1, of oval cross-section are provided at sheetpiling position of the table 384 to prevent injury to the bottom sheets of a pile as advanced from such position. Means for guiding the pushers as the chains move over the pulleys, and a guard 472 to prevent them from fouling the operating mechanism are provided. The hydraulic operating mechanism may be replaced by other mechanism for carrying out the invention. To stop automatically the operation of the elevator fitted with the fingers 129 when the supply of reserve piles runs out, or a pile is missing at elevator loading position, a trip arm 485 is mounted on a shaft 483 on which is pivoted a roller which passes through an aperture in the feed table to engage the bottom of a new pile 385. If a pile is missing the arm 485 is raised to the position shown by dotted lines in Fig. 1a, and will fail to operate a triplever 309 which normally controls the raising of the piston 133 which raises the fingers 129 to bring the new pile into sheet-feeding position.