GB564830A - Improvements relating to electromagnetic switches - Google Patents

Abstract

564,830. Electric signalling systems. TOMLINSON, A. V. (Union Switch & Signal Co.). Oct. 19, 1942, No. 14614. [Class 40 (i)] [Also in Groups XXX and XXXVII] In a switch particularly adapted for signalling apparatus, wherein a signalling arm 4 is moved from a normal position into one or other of two positions according to the polarity of the actuating current, each of two contact-carriers 34a, 34b has back contacts such as 30a which are closed in the "release" position of the switch, and are held against accidental opening by vibration by means of an armature 54a on a flexible strip 44a carried by the carrier, which armature co-operates with a pole 45a of a permanent magnet. In the form shown, the carrier 34a is pivoted at 36a, is gravity-biassed and carries an arm bearing against a stop on a pivoted arm 18 which is also gravity-biassed and bears on a roller 16 on a triangular member 14 fixed to a rotor (not shown) which is moved in one direction or the other from a central position according to whether a winding on the rotor is energized in one direction or the other ; and there is a similar contact-carrier 34b, pivoted at 36b and co-operating with a similar pivoted arm 17 which bears on a similar roller 15 on the member 14. The carrier 34b is also provided with an armature 54b which cooperates with a pole 45b of the magnet. Movement of the rotor one way or the other operates one or other contact rocker 34a or 34b and also brings a colour filter 5 or 7 into position instead of the " normal " filter 6 for signalling purposes.