GB828156A - Improvements in automatic counting devices, especially for duplicating and printing machines - Google Patents

Abstract

828,156. Counting-apparatus. BLOCK & ANDERSON Ltd. March 19, 1956 [June 15, 1955], No. 17282/55. Class 106 (1). [Also in Group XVI] An automatic pre-set counting device for stopping a power-driven machine for performing repetitive operations, after a desired number of such operations have been performed, comprises a ratchet wheel mounted for rotation to tension a restoring spring, a feed pawl adapted to be operated from a power-driven shaft to advance the ratchet wheel step-by-step against the spring tension, a pre-setting disc lockable in one of a number of angular positions for determining a selected number of steps to be completed by the ratchet wheel between an initial position wherein an abutment on the ratchet wheel engages an abutment on the disc and an end position, and means operative in said end position to disengage a check pawl to allow the ratchet wheel to return to its initial position, the feed pawl being lifted clear of the ratchet wheel on each return stroke of the feed pawl so that the ratchet wheel is free for return movement by the spring when the check pawl is disengaged. In the initial pro-set position of the ratchet wheel C, a post H thereon is urged by a tension spring G against a stop plate J on a pre-setting disc K, which is pre-set by means of a lug M on a locking lever L engaging one of say fifty teeth on the disc, so that the ratchet can rotate counter-clockwise against the action of the spring G through a desired number of steps each equal to one ratchet tooth before the post H strikes a trip-lever X to stop the machine. On each revolution of the printing drum, a cam T acts on a roller on a lever D to rock clockwise a lever N pivoted at O, whereby a feed pawl A pivoted on the lever N is moved away from a trip post B, and a spring A 1 engages the pawl with a ratchet tooth, further movement of the lever N causing the ratchet wheel to move one step counter-clockwise. On the first stroke of the lever N, the latter strikes an adjusting screw P 1 on a lug P of a retaining lever F to swing the latter clockwise and release a block R on the lever arm of a check pawl E, whereupon a spring E 1 moves the nose of the pawl E into engagement with a ratchet tooth to prevent clockwise movement of the ratchet wheel. The block R then prevents counterclockwise movement of the lever F. At the end of the desired number of revolutions of the printing drum, the post H strikes the lever S to stop the machine, and a post Q on the ratchet wheel strikes a cam face E 2 of the pawl E to move the latter clear of the ratchet teeth, whereupon the block R is moved to allow the lever F to re-engage it. The ratchet wheel is thereupon returned by the spring G to its initial pre-set position. If the disc K is set one step further clockwise than the position of the drawing, a blocking plate X on the ratchet wheel is brought into the path of the pawl A, and the machine runs continuously. Specification 769,707 is referred to.