GB191421176A - Improvements in and connected with Signalling in Mines. - Google Patents

Abstract

21,176. Black, G. J. F. Oct. 19. Mechanical telegraphs.-In mechanical step - by - step signalling - devices such as are used in mines for communicating between the bottom of the shaft and the engine-room, and in which the first portion of movement of the signalling- handle automatically cancels the previous signal, the remaining portion of the movement constituting the signalling stroke, the engine-room apparatus, of known type, is provided with a pawl 39 pivoted to the actuating-lever 40 operated by pulling the wire 29. The pawl 39 engages the notched end of a member 44 moving with the detent 41 on its pivot 45. On the wire 29 being pulled, the pawl 39 first moves the member 44, and with it the detent 41, to release the ratchet-wheel 42, which, with its pointer 43, thereupon returns to the zero position under the action of a chain 47 and spring- actuated lever (not shown). Further movement brings the pawl 39 clear of the end of the member 44, allowing the detent 41 to return into engagement with the ratchet-wheel 42. Further movement constitutes the signalling stroke, in which a pawl 50 is caused to engage with, and move, the wheel 42. The pawl 50 is pivoted to a sliding member 51 having a stud (not shown) engaged during the signalling stroke by a finger 53 carried by the lever 40.