GB1316018A - Suction-operated device for feeding sheets - Google Patents

Abstract

1316018 Feeding sheets MABEG MASCHINENBAU GmbH 14 July 1971 [16 July 1970] 32954/71 Heading B8R A suction device for separating sheets 31, Fig. 4, one by one from the top of a pile 2, and feeding them to a point of utilization comprises a cylinder 1, Figs. 1, 2 and 4, open to atmosphere at the top through an opening 30 and having a fixed bushing 16 having a central axial bore and ducts 19 therein. Above the bushing is slidable a piston 24 to which is attached a stop member 26 of adjustable length which slides in the bore in the bushing. Below the bushing is slidable a piston 4 having ducts 5 therein and a hollow tube portion 3 which passes through the bottom of the cylinder and causes a suction head 6 having ducts 10, 11, 12 leading into the space 13 in the tube 3. The piston 4 is urged upwards by a spring 15 to the position of Fig. 1. A conduit 22 connects the space 8 below the piston 4 to a source of suction or to atmosphere. In the initial position of the parts, there are, in addition to the space 8, spaces 23 and 21 respectively above and below the piston 24, and all the spaces are connected to atmosphere. When a sheet is to be picked up, suction is applied to the conduit 22. Vacuum is produced in the space 8, in spite of the influx of air through the ducts 10, 11, 12, and also through the ducts 19, 5, the latter causing a reduced pressure in the space 21 so that the atmospheric pressure in the space 23 depresses the piston 24 to its lowest position, Fig. 2, the stop member 26 protruding below the bushing and depressing the piston 4, so that the space 21 disappears and the air therein is transferred to a newly found space 20 below the bushing. Since the pressure in the space 8 is lower than in the space 20, the piston 4 continues to move downwards to the position of Fig. 4, when a sheet is picked up. As soon as air flow through the ducts 5 equalizes the pressure in the spaces 8, 20, the spring 15 moves the piston 4, with a sheet carried by the head 6, up to the position of Fig. 2, where it is stopped by stop member 26 which is acted on by atmospheric pressure from above. The device now moves the sheet to a point of utilization, and the suction is now disconnected from the conduit 22, as a result of which the sheet is released from the head, and the spring 15 returns the pistons to the position of Fig. 1, ready for the next cycle. The device can operate at 12000-14000 cycles (or sheets) per hour.