GB747664A - Improvements in sheet feeding mechanism - Google Patents

Abstract

747,664. Feeding-sheets. CRABTREE & SONS, Ltd., R. W. Dec. 16, 1953 [Dec. 16, 1952], No. 31881/52. Class 100 (1). Faulty feed detectors.-In sheet-feeding apparatus sheets which are improperly located are detected by a feeler which is moved across the path of movement of the sheets in such timed relationship that the feeler in its movement clears sheets which are properly disposed but engages those which are improperly disposed, and in such engagement means is operated to control the operation of the sheet-feeding or associated apparatus. As shown, a detector unit A, which is operated by suction at regular intervals under the control of a valve unit B, includes a feeler 3 which is reciprocated vertically to pass through an aperture in a feed board 1. If a sheet S is improperly located on the board 1 and impedes the downward movement of the feeler 3, a switch in an electric or fluid-pressure circuit D is closed to effect a control of the apparatus or the associated machine: for example the supply of suction to sheet-separators may be cut off, or the cylinders of a printing-machine may be tripped. The feeler 3 is slidable in a sleeve 4 integral with a piston 5, the latter being slidable in a cylinder 6 which is connected at 7 to a suction conduit 8. When suction is applied, the piston 5 is drawn down against the action of a spring 9 and this movement is transmitted to the feeler 3 through a second spring 11. If the feeler 3 is stopped by a sheet S, the piston 5 and sleeve 4 continue their movement, against the action of the spring 11, and this relative movement is employed to close a switch 14 in the circuit D. A rod 15 secured to the feeler 3 carries a block 16 provided with a cam face 16<SP>1</SP>, and the latter acts on a pawl 17 pivoted to an extension 4<SP>1</SP> of the piston 5 to close the switch 14 when there is relative movement between the feeler 3 and sleeve 4. The cylinder 6 is carried by a bracket 12 mounted on an adjustable rail 13. The suction pipe 8 is connected to the valve unit B which includes a rotary valve driven through gearing C in phase with the printing &c. machine with which the sheet-feeder is associated, whereby the pipe 8 is connected to a suction pipe 29 at the appropriate times. Means is provided in the drive of the rotary valve to enable the timing of the connection between the pipes 8, 29 to be varied.