GB512895A - Improvements in or relating to railway signal and/or points control systems - Google Patents

Abstract

512,895. Railway signalling apparatus. STANDARD TELEPHONES & CABLES, Ltd., GRIFFITHS, J. B., and BROWN, A. March 15, 1938, No. 8023. [Class 105] Miniature-diagram control panels for railway signalling purposes have means to notify the operator if operation of a manual control switch for route, points or signal setting is undesirable; such means may consist of an electromagnet detent restricting the movement of the control switch. Tne route control switch shown is rotated to a position corresponding to the desired route and is then pushed in. A detent I engaging a disc H limits the inward movement but is released when a magnet M is energized over contacts D controlled by cams C on a spindle U rotated by the hollow shaft B of the switch, contacts L closed by a cam collar J, and contacts of other route control switches checking that no conflicting route is set up. The inward movement can then be continued to close contacts O which in conjunction with contacts D effect operation of the various points in the route. A detent N is released when all the points for the route are set and thereupon the inward movement of the switch can be completed so closing contacts Q which with contacts D clear the signal. The return outward movement first opens contacts Q to set the signal at danger but the 'complete return can only be effected if an approach section is free so that a detent R is released over contact S and contacts D. This locking of the route switch is also described as applied to the route setting apparatus having motor-driven sequence switches described in Specification 496,495 the first detent being released when the sequence switch has stopped in route-setting position and the second detent when the points for the route have been set. Specifications 498,143 and 518,387 also are referred to.