GB191517918A - Improvements in Visual Signalling Indicators for Collieries and the like Works. - Google Patents

Abstract

17,918. Jobling, J. W. Dec. 22. Bell and gong signals; mechanical telegraphs.- A signalling-device for collieries and like works has two pointers moving together step by step to indicate on a dial the number of signalling- impulses given, one pointer returning to zero after a pause controlled by a dash-pot or like retarding-device, and the other pointer remaining to register the signal until returned to zero by the first impulse of the succeeding signal. Figs. 2 and 3 are respectively front and rear views of the mechanism. An indicating- pointer f is secured to a spindle c provided with a ratchet-wheel g. A registering-pointer t is mounted on a sleeve d with a ratchetwheel y, and has a projection u engaged by the edge of the pointer f. A detent j, normally held out of engagement by a weight n, cooperates with the wheel g. Signalling-impulses imparted to a lever o raise the weight n and allow the detent to engage, and the wheel g and pointers are advanced one step for each impulse by a pawl s on an arm q depending from the lever o, a projection 5 on the arm preventing overrunning. Fall of the weight n to return the wheel g and pointer f to zero is retarded by a dash-pot or like device k. The pointer t is prevented from returning by a pawl z engaging the ratchet-wheel y until knocked out of engagement on a subsequent impulse by a pawl 4 on a plate 2 carried by the weight n. Overrunning of the pointer t is prevented by a pawl 7 which is allowed to engage a ratchet-wheel 6 on the sleeve d towards the end of an impulse by an eye 11 moving with the weight n and engaging nuts 8<a> on a sliding rod 8, thus raising a projection 9 on the rod clear of the pawl. A bell 12 is struck at each signalling-impulse by a pivoted hammer 13 operated by a ratchetwheel 14.