Patent GB-314540-A (GB)
Title: Improvements in or relating to electric signalling systems
IPC: H02J13/00
Filed: 1929-06-27
Abstract: 314,540. Associated Telephone & Telegraph Co., (Assignees of Hershey, H. E.). June 29, 1928, [Convention date]. Selectivc signalling and remote control systems. -An impulse transmitter for use in signalling, remote control or like systems comprises selecting keys X, Y, each adapted to transmit a particular code and auxiliary keys B, C, D adapted to modify the control of the impulse-sender in a pre-determined manner irrespective of which selecting key is operated. The Figure shows the application to a train despatching system in which the receiver comprises a selector 100 having access to four call bells and is operated by alternating impulses generated by relay 19. Transmission of code. The operation of a selecting key X operates and locks relay 13 and applying battery to the normal contact of wiper 71 energizes the start relay 12 which locks out all the selecting keys and a universal call key CK and connects the stepping magnet 21 in series with an impulse generator 20 lighting an indicating lamp 81. When the selector switch S is off normal relays 11, 12 are locked in series and the start circuit is opened at 48 so that the switch stops on reaching normal. On the fourth step wiper 70 energizes impulse relay 1 and, relay 18 having been energized by relay 12, the relay 19 repeats the impulses to line L1, L2 to form the first part of the code. On contact 7<1> wiper 72 energizes relay 9 which locks itself and the impulse relay 1 to provide a break. Relays 5, 6, 7 and 8 are successively energized the latter de-energizing relay 9 so that restoration is effected and code transmission proceeds from the ninth contact. At contact 12<1> wiper 73 energizes relay 10 which de-energizes relay 1 and again energizes relays 5 - - 8 to produce a second break after which impulsing proceeds to give the third part of the code which is terminated by the operation of relay 9 since wiper 72 picks up potential on contact 16<1> and stepping proceeds to normal after which the de-energizing of the relays produces a clearing impulse which restores the receiver to normal. Operation of auxiliary keys. If in addition to the selecting key one of the auxiliary keys B, C, D, is operated potential is removed from one or more of the contacts associated with wiper 72 so that additional impulses are transmitted to further step the selector 100 so that a different bell is rung. To ring for a longer period the locking stop key SK is operated which stops the switch S by de-energizing relay 12 and relays 1, 19 remaining energized the selector 100 is held until the key SE is released. To ring one of the other bells associated with the receiving selector 100 the advance key AK is operated to energize relays 2, 3, and thus two impulses are transmitted by the de-energizing and energizing of relays 1, 19, which advance selector 100. All stations may be simultaneously called by means of key CK which energizes relay 4 which locks and removes potential from the contacts of wiper 70 connected to springs 34 and energizes the starting relay 12. The contacts of wipers 72, 73 are not marked and seventeen impulses are transmitted consecutively upon which wiper 72 picks up potential on contact 16<1> and the restoration to normal is effected as previously. Other positions on the selectors may simultaneously be called by operating keys B, C or D in addition to the universal call key C. K. Specification 301,399 is referred to.