GB693970A - Improvements in sheet detecting devices - Google Patents

Abstract

693,970. Feeding sheets. BACKHOUSE, H. T. May 9, 1951 [May 10, 1950], No. 11653/50. Class 100(i) Faulty-feed control devices.-Relates to sheet-detecting devices, employed in printing machines to determine the non- arrival at the lays of a sheet, comprising a finger movable by engagement with the front edge of the sheet, non-movement of the finger being adapted to stop the machine or actuate a warning device. According to the invention, the finger 3, which is reciprocable from below the plane of the feed-board 1 to a position in which it projects above it, is pivoted on the reciprocatory means 6 and has an abutment surface 13 engageable with a detent 15 so that the finger cannot be withdrawn below the board unless it has been deflected by contact with a sheet. As shown in Fig. 1, the reciprocatory means comprises and arm 6 on a rockshaft 7 oscillated by a cam 10 and follower 9. The detent 15 is integral with a plate 14 mounted beneath the feed-board and adjustable by an eccentric 16. A light return-spring 12 ensures engagement between the detent and abutment. In a modification, Figs. 2-4 (not shown), the detent is mounted on the front lay and is retractable with it. Several detecting-fingers may be mounted across the width of the feed-board and may be disabled at will by providing means, such as a set-screw, for maintaining the abutment and detent out of engagement.