GB623151A - Improvements in or relating to sheet-feeding apparatus - Google Patents

Abstract

623,151. Feeding sheets. BELL, GIDDINS, & CO., Ltd., and BELL, W. April 22, 1947, No. 10717. [Class 100 (i)] Sheets are fed to printing &c. machines by the combined action of suction separators 1m acting on the rear of a pile, and front separators 2m, which are mounted in a reciprocating slide and advance the separated sheets over a fence 3b to feed-rollers 3, 3a, and suction cups 4m are also provided, and, in addition to assisting the rear separators, control mechanism for raising the pile. The separators are all carried by sliding pistons, and the timing of the separators is controlled by rotary valve mechanism which is so designed that the suction separators may be put out of action independently of the motion of the associated printing-machine, and when so tripped the suction to the separators is cut off, and acts upon the pistons carrying the separators so as to maintain the separators out of contact with the pile. On continuation of the feed the timing of the commencement of feed is controlled so as to synchronize with the action of the printing-machine. The separators 1m are carried by a plunger 1a fitted with two pistons 1h, 1g, of which the lower one is the larger. When suction is applied by a tube 1d to the space 1f between the larger cylinder and an extension 1k of the plunger 1a, the plunger rises, slowing under the differential suction action on the two pistons. At the same time, the separator 1m is connected to suction via ports 1i, 1j in the plunger and a restricted connection 1n. The separators 1m are raised more quickly when suction is applied by a pipe 1c to the cylinder 1b of piston 1g, and at the same time the separators 4m are raised by the application of suction to the piston 4g. The separators 2m are actuated similarly to the separators 4m and are operated from pipes 2c, 2d connected alternately to a suction source and to atmosphere. The piston 2g acts to lift the separators 2m after the top sheet is caused to adhere to the separators. The air pressure in the pipe 4d, 4c, 2d, 2c is controlled (1) by a main distributing valve member, comprising two rotary members 9, 10, Fig. 1, driven in synchronism with the printing-machine by a gear 13; (2) a control valve 14 movable between two extreme starting and stopping positions in one of which it permits normal operative control of the suction cups, and in the other it maintains suction on the plungers and cuts off suction to the suction cups; and (3) means for moving valve 14 to its extreme positions. As shown, this means consists of a valve 16 operated by a handle 16e, and serving to connect one or other end of a cylinder 15b to the main vacuum chamber 12c associated with valve members 9, 10. A piston 15d in the cylinder 15b is thus moved to one or other of its extreme positions, and by acting upon an arm 14h of the valve 14 the feed is either started or stopped. The control valve 14 may be operated otherwise than by suction, and need not be formed in unitary connection with the valves 9, 10. The pile-raising means is formed of an oscillating lever having a pawl which is normally kept from engaging a ratchet concentric to the axis of the oscillating lever by a spring-plunger engaging a pin on the pawl. The plunger is withdrawn by suction when a piston 4h in the cylinder 4b drops below an outlet 4p connected by a pipe 4r to the cylinder in which the spring- plunger is fitted. The pawl then engages and operates the ratchet, which is geared to tho pileraising gear. The suction passage in the plungers may be provided with air-filtering medium.