GB915022A - Apparatus to automatically raise a platform supporting a pile of sheets - Google Patents

Abstract

915,022. Feeding sheets. ROTAPRINT Ltd. Feb. 5, 1960 [Feb. 5, 1959], No. 4141/59. Class 100 (1). Pile tables.-In apparatus for raising a platform for supporting a pile of sheets, the raising mechanism is controlled by an air pressure-responsive device, and the pressure in this device is controlled by a feeler engaging the top of the pile. As shown, sheets are fed from the top of a pile 26 on a platform 17 by suckers 25 which forward them to a rotary offset printing-machine, and the platform is raised to keep the top of the pile at a substantially constant level by chain means operated intermittently by a vertically reciprocating pawl 10 acting on a ratchet-wheel. The pawl 10 is reciprocated through a crank lever 9, a bar 1, a second crank lever 3 secured to a shaft 4, and a lever which is secured to the shaft 4 and rocked by a cam secured for rotation with the impression cylinder of the printing-machine. Depending upon the position of the cam, a spring 18 moves the bar 1 to the left to lower the pawl 10, and the cam moves the bar 1 to the right to raise the pawl and operate the pileraising mechanism. Movement of the bar 1 to the left is prevented when a stop-lever 19 is in the raised position shown, since it lies in the path of a projection 2 on the bar 1. The lever 19 is pivoted to the rod 21 of a piston 22 in a cylinder 23 which is connected by a pipe 34 to a suction line 33. The line 33 is connected to an adjustable device 35 having a nozzle 32. The nozzle 32 is closed by a flap 31 on a pivoted feeler lever 29 when the height of the pile 26 is depleted by a predetermined amount, so that suction builds up in the pipes 33, 34; the piston 22, rod 21, and lever 19 are then lowered, and the bar 1 can be reciprocated to cause the pile to be raised. The suction line 33 can be so connected to the suction system, that the lever 19 will not be lowered if the suckers 25 fail to pick up a sheet.