GB1153617A - Improvements in or relating to Sheet Feeding Apparatus - Google Patents

Abstract

1,153,617. Sheet-feeding; tripping. GESTETNER Ltd. 12 June, 1967 [15 June, 1966], No. 26719/66. Heading B6C. A detector for paper sheets and equipment control device, especially for the pressure roller of a stencil duplicator, comprises a guide for sheets fed to the equipment, an actuating member which is engaged by a sheet being fed to operate a valve, and pneumatic operating means for the equipment controlled by the actuation of the valve. Fig. 1, illustrates such a device in which the main drive shaft 32 for the printing cylinder of a stencil duplicator carries a cam 6; the cam follower is a roller 15 carried on a pivoted lever 16 which engages a boss 33 on a master piston 4 slidable in a master cylinder 5 against the action of return spring 17. At each cycle of the duplicator, piston 4 is depressed building up pressure in side chamber 20 until the spring 17 returns the piston, the cylinder being vented through apertures 18, 19. When no sheet is fed, detecting finger 1 is in its Fig. 1 position resting against paper frame 2, the arrangement being such that air is vented from chamber 20 through conduit 23 and out of a bore (34) Fig. 2 (not shown), in valve body 24 and sleeve 25, whenever piston 4 is depressed; there is no pressure build-up in second conduit 26 which is also connected to side chamber 20. If a sheet is fed, then detecting finger 1 is rotated (Figs. 2, 4, not shown) closing the cross-bore (34) in valve 24. Pressure then builds up in conduit 26 when the piston 4 is depressed, forcing control lever 8 to rotate about pivot 9 under the action of a further piston 7 in a slave cylinder. A further cam (14) mounted on drive shaft 32 (Fig. 5, not shown), oscillates a two-arm lever (13) which carries a fixed peg 12; in one direction of oscillation, the peg 12 engages arm 31 of control lever 8 and moves it laterally; the pressure roller (36) which is mounted on lever 8, is thus forced against the printing cylinder (38) (Figs. 3, 4, 5, not shown), whereon when no sheet is fed, the peg 12 slides into the recess between arms 30 and 31 of the control lever and causes no movement thereof (Fig. 1). Specification 973,108, in which the detector prevents actuation of the pressure roller only when no sheet is fed, is referred to.