GB177321A - Improvements relating to intermittent driving-mechanism for feeding continuous stripmaterial - Google Patents

Abstract

177,321. Forgrove Machinery Co., Ltd., and Grover, F. Jan. 28, 1921. Variable-speed ratchet gearing.-In web-feed mechanism for wrapping-machines &c., of the kind in which a friction ratchet-gear such as a notched pawl 3 engaging an annular flange 1<x> on a wheel 1 geared to the feed rollers 10 is employed, the effective stroke of the pawl 3 is automatically controlled by a pivoted stop 21 operated pneumatically and controlled by perforations 11<x> in the web. The perforations 11<x> pass over an aperture 13 in a casing 14 closed by a diaphragm 15 connected to the stop 21 by a rod 16, arms 17, 19, and link 20. A pivoted hollow arm 12 registering with the aperture 13 is connected to a vacuum pump 23 operated by a cam 26 on the shaft 7 which, through crank 6, links 5, and arm 4<x> operates the pawl 3. If the web is fed correctly, a perforation 11<x> registers with the aperture 13 at the end of each feed movement and the vacuum which is set up in the casing 14 moves the stop 21 into the position shown in dotted lines and limits the idle stroke of the pawl 3, but if a perforation 11<x> is not in register with the aperture, the stop remains in the position shown in full lines so that the pawl receives a longer idle stroke. The vacuum in the casing 14 is destroyed during each feed movement by leakage of air into the casing through a narrow valve-controlled passage.