Patent GB-1413604-A (GB)
Title: Mechanism for feeding separating and stacking sheets
IPC: B41F31/08
Filed: 1973-01-30
Abstract: 1413604 Feeding and delivering sheets PENNSYLVANIA RESEARCH ASSOCIATES Inc 30 Jan 1973 [22 Feb 1972] 4515/73 Heading B8R Sheets separated from a pile are forwarded by drive-rollers which co-operate with stripper rollers rotating in the opposite direction to feed so as to prevent double feed, the drive and stripper rollers being arranged so as to cause sheets passing therebetween to assume an undulating shape in a direction transverse to the feed direction. Pile supports.-A pile of sheets S, Fig. 1, for separation from the bottom rests in a hopper 14 on a support plate 15 and against a first plate 16. The plate 15 is formed in two portions 15a, 15b at an angle to each other to relieve the weight of the front of the pile, which weight is also relieved by the plate 16 being roughened or having a corrugated or stepped form. In another form, Fig. 4, for separation from the top, an upper guide-plate 123 has a pivoted portion 123a which, when it falls under gravity as the height of the pile is reduced, operates a microswitch 123d to cause a shaft S<SP>1</SP> to be rotated to raise the support plate 121<SP>1</SP>. Sheet separators.-The end sheet is separated from the pile by a roller 19, Figs. 1 and 4, having a high-friction raised segment insert 19a which has the effect of agitating the pile to assist separation. Sheet forwarders.-Separated sheets are fed forwards by one or more drive rollers 23 and anchoring rollers 60 to an endorsing or stamping wheel. Preventing double feed.-The drive rollers 23 co-operate with one or more stripping rollers 52 rotating in the direction opposite to feed and having a lower co-efficient of friction than the drive rollers to return a second sheet to the hopper if two sheets are separated together. The drive and stripping rollers are laterally staggered and extend radially beyond each others' peripheries so as to produce lateral undulations in the sheet. Alternatively, the drive or stripper rollers are formed with one or more convex peripheral portions extending into one or more concave peripheral portions in the stripper or drive rollers. The stripper rollers are mounted on pivoted members 32, 33 spring-urged towards the drive rollers. Sheet forwarders.-The accelerating rollers 60 co-operate with idler rollers 65, there being four of each, of which the inner two have a higher coefficient of friction than the outer two, and the outer two idler rollers are positioned slightly downstream of the inner two. This arrangement corrects or reduces any skewing of the sheets. Directing sheets to alternative paths.-Sheets are directed either by belts 207, 208, Fig. 1b, to a waste container 215 or by a guide plate 16c to a stacker 80, Fig. 1, according to the setting of a pivoted gate 201 controlled by a counter actuated by a photo-electrical detector 71, 72, in response to the setting of a programming switch. The switch may be set for sampling, e.g. to direct every 100th sheet to the stacker, for forming stacks of counted sheets, e.g. by feeding 50 sheets to the stacker and delaying the feed of the next sheet while the stack is removed, or for feeding alternate sheets to two stacks. In any case, a feed delay is produced before the movement of the gate or for removal of the stack by operating an electromechanical clutch- and-brake assembly to stop rotation of the rollers 19, 23, 52 and 60. Stacking sheets.-Sheets to be stacked are guided between plates 16c, 81 and pushed by rollers 84 against a plate 83. As the stack is formed, it forces a member 112 carrying the plate 81 backwardly along a slot in the plate 83 against the direction of a spring 95, which acts on the member 112 through a pulley arrangement 106, 107 which gives a mechanical advantage to the member 112.