GB256602A - Improvements in and relating to remote control switching systems - Google Patents

Abstract

256,602. British Thomson-Houston Co., Ltd., (Assignees of Bird, L. F.). Aug. 5,1925, [Convention date]. Distant control systems.-An electric circuit is closed or opened from a remote point by impulses of short or long duration respectively. As shown in Fig. 4, a circuit 1 is closed by a switch 2 when the armature 8 is attracted by a relay 6 upon the receipt of a short impulse. The armature 8 enters a recess 4 and allows the member 3 to fall and close the switch 2. Upon cessation of the impulse the armature 8 falls back, under its own weight or the influence of a spring to the right hand side of the recces 4 as shown in Fig. 1 and the circuit is maintained closed. In the " open " and " closed " positions of the switch, an extension 9 of the armature 8 closes contacts 10, 12 to charge a condenser 13 and supply negative bias 14 to the grid of a discharge tube 14 to prevent a current flow through the tube 14 and a relav 7. When it is desired to open the circuit 1, an impulse of relatively long duration is transmitted and the armature 8 is attracted to permit the completion of a discharge circuit for the condenser 13 through the contacts 10, 15 and a resistance 16, and the production of a gradually increasing current through the tube 14 and relay 7. The contacts 10, 15 are maintained closed for a time sufficient to allow the current to reach a predetermined value which causes the relav 7 to attract the armature 18 and raise the member 3. To open the circuit 1 upon the cessation of the long impulse the armature 8 falls back beyond the recess 4 as shown in Fig. 4 since the relay 7 is maintained energized until the contacts 10, 12 are closed to supply negative bias to the grid of the tube 14. In this position the armature 8 engages an extension 5 of the member 3 to hold open the circuit 1. In a modification, Fig. 5, the operation of the relay 7 is controlled by a dashpot 19. The arm 20, controlled by the relay 7, is actuated only upon the receipt of a long impulse. Specification 255,845 is referred to.