GB319600A - Improvements in and relating to electric signalling and indicating apparatus and the like - Google Patents

Abstract

319,600. Cowx, H. S. June 20, 1928. Non-seleclive audible and visible signalling systems.-In a signalling system of the type wherein, upon operation of a signalling switch. a bell and a lamp or other indicator are operated, and, upon release, the bell ceases ringing but the lamp &c. is maintained operated by a relay, the relay is provided with two or more windings arranged in parallel, one of the windings being connected in series with the lamp while the other windings serve to supplement the force of attraction of the first winding of the relay in order to ensure operation even when the resistance of the circuit including the first winding is unduly increased. As shown in Fig. 1, operation of a switch 12 rings a bell 15 and energizes a relay over a circuit including a winding 16 and indicator lamps 20. A second winding 27 is normally energized in a circuit including a pilot lamp, resistance, cholie, &c. 28, so that upon energization of the winding 16 the armature 17 is attracted to close a locking circuit for the relay through the armature, winding 16, and lamps 20. In this manner the lamps are maintained operated while the bell ceases ringing upon release of the switch 12. The lamps may be extinguished by switches 22, 21 arranged in the locking circuit, the switch 21 having an auxiliary contact 24 and a delay-acting device 26 adapted to maintain open the locking circuit and to cause operation of a bell 25, which may be situated at a remote point, for a predetermined time. A number of separate lamp circuits may be controlled by the switch 12, or a group of lamp circuits may be operated by a corresponding number of switches 12 which are, however, common to a single switch 21. In the modification shown in Fig. 2, the relay has two windings 34, 36 connected in parallel and two armatures 40, 41. Upon depression of the switch 32, the relay is energized in a circuit including the lamps 37. A bell 48 is operated in a circuit including the armature 41 and the armature 40 closes a locking circuit over a resistance 44 which reduces the holding current sufficiently to release the armature 41 and open the bell circuit when the switch 32 is released. Auxiliary signalling devices may be included in the circuits of the additional windings 27, 36, if desired. The systems may be operated from a d.c. or a.c. supply.