GB139994A - Improvements in and relating to electrical signalling apparatus - Google Patents

Abstract

139,994. Railing, M. J., and Connaughton, J. J. V. July 11, 1919. Mine signalling systems; order apparatus; recording orders.-In electric signalling- apparatus comprising a ratchetoperated pointer and dial, particularly adapted for mines, each signal is normally cancelled by the next following signal, but the " men on " signal is additionally recorded by illumination of a panel, which persists until the engine starts, as a reminder to the engineman. The pointer is turned step by step, against the tension of the resetting-spring w<1>, by a ratchet m and pawl p, the pawl p being mounted on a lever n which is oscillated by the impact of a set-screw t carried on the cone-shaped core u of the solenoid s, whenever the solenoid is energized. The bell w is rung at the same time by the lever x, which is actuated by the plunger u through a pin working in a slot y in a link y<11>. The ratchet-wheel m has its surface cut away at c<11> to limit its rotation. The signal is cancelled when the holding-pawl p is retracted by the magnet f on receipt of a fresh signal, or by the magnet g on the engine's starting. The signalling-impulses energize the relay d, which closes two circuits, one through the solenoid s which actuates the signal pointer as above, and one through the cancelling-magnet f. The cancelling-magnet f is thus energized by the first of each set of impulses, but it is immediately afterwards thrown out of action till the set has been completed. For this purpose, the circuit of the magnet f is broken by a time-lag device or dash-pot after the. first impulse. The circuit passes through a spring contact x<1> and the selflubricating graphite piston a<1> of the dash-pot, so that it is broken when the piston a<1> is pressed upwards by the solenoid core u. A ball valve d' in the cylinder b<1> permits the piston a<1> to rise freely, but retards its downward motion. When the cancelling-magnet f has been thus de-energized, the pawl p<1> is returned to the position shown in Fig. 1 by the weight s<1>, after an interval during which the weight is thrown upwards and falls again, its neck passing freely through a hole in the arm r'. When three impulses (meaning " men on ") have been received, a roller f<1> revolving with the ratchet-wheel m closes a contact at g' and so, as soon as the contact x<1>, a' has been re-established, closes a circuit through the lamp, which illuminates a " men " panel. The same operation also closes a circuit through the self-holding relay e, which ensures the continued illumination of the lamp even when subsequent signals are received. To enable trains of more than three impulses to be registered while the lamp is alight, a separate locking-winding may be provided on the relay e. The " men " signal is only cancelled when the circuits concerned are broken at c<11> by the magnet g, which is energized by the starting of the engine. The parts described are mounted on a slate slab.