GB1228575A - - Google Patents

Abstract

1,228,575. Feeding sheets. PLESSEY CO. Ltd. 15 Aug., 1968 [16 Aug., 1967], No. 37756/67. Heading B8R. Spaced along a conveyer track 1 are a series of hopper units each including an exchangeable magazine 15 for a pile of sheets. Above each magazine is a suction separator drum 5 having ports 6 connected to a suction source, whereby the top sheet can be separated, when suction is released from a retaining suction foot 25, and fed by the drum and belts 16 through a throat 4 on to the conveyer path, along which it is fed by rollers 2, 3. A rotary valve connects the foot 25 to a suction source except during the part of the drum revolution when a sheet is to be separated, and at this time connects it to a two-way valve controlled by a solenoid actuated by a programming device which connects the foot to atmosphere if a sheet is to be separated from that particular magazine and to the suction source if not, so that sheets can be supplied to the conveyer path from the various magazines in a desired order. The pile table 18 is raised by a pneumatic device 22 until the top of the pile reaches a detector 24, and is again raised when the level falls below the detector. Double feed is prevented by air from nozzles 26 blowing against the side of the top part of the pile, and by the foot 25, which is reconnected to the suction source to hold the next sheet as soon as the rear end of the top sheet has passed from beneath it. In another form, sheets are separated from the bottom of the magazines, which are above the conveyer path.