Patent GB-362058-A (GB)
Title: Improvements in and relating to signalling systems
IPC: H02J13/00
Filed: 1930-09-23
Abstract: 362,058. Electric signalling systems. SIEMENS BROS. & CO., Ltd., Caxton House, Tothill Street, CHRISTIAN, D. A., Morven, Charlton Road, Charlton, and VOSPER, W. T., 6, Timbercroft Lane, Plumstead, all in London. Sept. 23, 1930, No. 28484. [Class 40 (i).] In a system wherein signals are transmitted from a control point to a number of substations over common lines, after the transmission of a signal for setting apparatus such as stepping switches at the substations, a further signal is transmitted the receipt of which at the substations causes signals to be reverted to the control point indicative of the setting of the apparatus. Fig. 1 shows the equipment at the control point and Fig. 2 the apparatus at a single substation, The substations are connected in parallel across the common line wires + -, and in the arrangement shown each substation has a switch SA for controlling lamps WL. In order to operate a particular lamp WL the appropriate number of impulses is transmitted by the dial switch DS which during setting operates relays I, B and during release impulses the line at contact i1 Line. relays A at the substations are thus impulsed, and at contacts such as a1 magnets SA are operated to advance the switch wipers SA1 . . SA4. At each station relays C, D remain operated during impulsing. At the end of impulsing C releases to close over contact d2 (D remaining held over a1, d1) the circuit of the selected lamp WL. An audible alarm WB also is operated over wiper SA2. The test key TK at the control point is then operated to associate the magnet SC of switch wipers SC1, SC2 with the impulsing contact a1 and a further train of impulses, the number of which exceeds the maximum number of impulses used in a setting signal, is dialled. The impulses operate switches SC, SR in synchronism and as the latter is stepped into engagement with a contact in bank SRI marked in accordance with the position of wiper SA1, relay B is operated to revert at contact b1 an impulse to the control point and operate relay M. Relay M operates a relay LR corresponding to the operated lamp WL over wiper SC1 and thereby illuminates an appropriate lamp L. If a switch SA at one of the substations occupies a different position to similar switches at other substations, a second signal is reverted to operate a second lamp L. To restore the equipment at the substations to normal positions, key CK is operated and then released to cause operation of slow-release relays X, Y which transmit a long impulse to relays A and thereby effect the release of relays D which complete the homing circuits of switches SA, SR over wipers SA3, SR3. The key TK also is restored to close of homing circuit of the control station switch. After the receipt of a signal and the corresponding testing train ,the equipment at the substation may be restored by operation of key AK which remains short-circuit by wiper SR2 until termination of the test train. In a modification the test train operates the switch SR, which at each step reverts an impulse to operate switch SC, a marginal relay at the control point remaining inoperative until the switch SR arrives at the marked contact.