GB122136A - An Improved Non-accumulative Electric Signalling Indicator for Colliery Shafts and the like. - Google Patents

Abstract

122,136. Brown, H., and Evans, J. H. July 29, 1918. Mine signalling systems; order apparatus.-In a mine signalling system comprising a step-by-step ratchet- and-pawl visual indicator and an audible indicator in the form of a single-stroke bell, the pawl-operating magnet is provided with a second armature which closes the bell circuit at each operation of the visual indicator, and the armature levers are retracted bv counter - weights instead of springs. The pointer of the visual indicator is operated through a rack and pinion, the rack being provided with a set of pawl teeth, and the setting of the pointer is effected by an adjustable screw engaging a projection on the rack. The circuit of the re-setting magnet is controlled by a switch actuated by a governor driven bv the engine and the sensitiveness of the governor is increased by a weighted lever engaging the under side of the sleeve. The re-setting circuits of several indicators may be controlled by a single governor switch. The magnet 11, Fig. 2, energized from a battery 2, Fig. 1, through an impulse switch 24, is provided with an armature lever 13 carrying an actuating pawl 16 and an armature lever 19 adapted to close contacts 22, 23 in the circuit of the bell 8, Fig. 1. The levers 13 and 19 are retracted by weights 15 and 21. The pawl 16 engages teeth 17 on a sector 17<a> which is provided with gear teeth 25 engaging a pinion 26 on the arbor of a pointer 27, Fig. 1. The sector 17<a> is provided with a projection 49 engaging an adjusting screw 50 by means of which the pointer 27 is set. The circuit of the re-setting magnet 40 contains a switch 34, 36, Fig. 1, the element 34 of which is mounted in the sleeve 33 of a governor. To increase the sensitiveness of the governor, the under side of the sleeve is engaged by a lever 35 carrying an adjusting weight 35<a>.