GB191423921A - Improvements in Signalling Apparatus for use in Mines. - Google Patents

Abstract

23,921. Chalmers, S., Black, G., and Black, J. Dec. 11. Mechanical telegraphs. -Relates to signalling- apparatus of the type described in Specification 21,369/14. Three pointers are employed, namely an "active-signal pointer" 6, a cautionary-signal pointer " 8, and a " destination-signal pointer " 9, the pointers 8, 9 being adapted to be moved in a clockwise direction by a tongue 7 on the pointer 6. The pointers 6, 8, 9 are fixed respectively on a shaft 4, a sleeve 10, and a sleeve 11. A ratchetwheel 3, mounted loosely on the shaft 4 but driving the same by a pin 5, is moved round step by step by a pawl 1 on the signalling-rod 2, and is sustained temporarily against counter - clockwise rotation by a detent 13 co-operating with a timeabsorbing device 14, 15. During this period, an engine-operated detent 16 engages with a ratchetwheel 17 on the shaft 4, the wheel 17 being so formed that the detent 16 is operated only when the pointer 6 occupies a position opposite the No. 1 and No. 2 indications on the dial, and the detent 13 coming into operation while the detent 16 is inoperative. The sleeve 10 carrying the pointer 8 is fitted with a ratchet-wheel 18 engagable by an engine-operated detent 20, which holds the pointer at the "Men" indication. The sleeve 11 carrying the pointer 9 is fitted with a ratchet-wheel 21 engageable by an engine-operated detent 22, the wheel 21 having teeth commencing at a point corresponding to - the " Men " indication and terminating at the point of maximum travel of the wheel. The wheels 17, 18, 21 are loaded so as to return to zero on raising the respective detents. The tines 16<a>, 20<a>, 22<a> of a forked bell-cranked lever 23, pivoted at 24 and operated by a roller 25 engaging a cam-track on its inner surface, straddles the detents 16, 20, 22 and affords shoulders for supporting the detents on predetermined occasions to render them inoperative. Means operable according to the positions of the pointers are provided for elevating the detents 16, 20, 22 to permit their engagement with the shoulders and render them inoperative, the means being such that the pointer 9 is always released on the execution of contradiction signals, or on the next actuation subsequent to any signals other than those which involve operation of the winding-engine.