Patent GB-301399-A (GB)
Title: Improvements in or relating to electric signalling or controlling systems
IPC: H02J13/00
Filed: 1928-11-28
Abstract: 301,399. Associated Telephone & Telegraph Co., (Assignees of Hershey, H. E.). Nov. 28, 1927, [Convention date]. Selective distant control, and signalling systems.-Relates to a system for the selective operation of apparatus units, such as circuit breakers, at a number of substations or signalling devices such as the call bells of a train despatching system or the semaphores of a train signalling system. The substations are arranged in parallel across a pair of line wires, and selection of any particular unit at a substation is effected by a three-train impulse code, the total number of impulses of the three-impulse codes being fixed. All the substations may be called simultaneouslv if desired. The impulse codes are transmitted under the control of a step-by-step switch which is adapted to be appropriately marked by control keys at the central station. The system is applicable to known selective signalling systems employing code transmitters of the ordinary interrupter type which are adapted to transmit three-train impulse codes to operate step-by-step switches which are mechanically held or released according to the code transmitted. Fig. 1 shows the control station and Fig. 2 a remote station W having devices 169, 170 adapted to be selected in a manner according: to the the invention and a substation 171 employing a step - by - step selective switch of known type. An impulse sender K3 of known type also is shown at the control station. The first train of a selective signal is adapted to select one or more substations, and the second and third trains effect the operation of one or more units or signalling devices at the, selected stations. In the apparatus shown, arrangements are made for the transmission of a total of twenty-seven impulses for each signal. The selectors W at unwanted stations are locked unresponsive to further impulses, and the selectors 171 at such stations are mechanically released. When it is desired to effect a particular selection, the appropriate key such as K1, k2 is operated to mark the switch X and initiate stepping under the control of a constantly driven impulse generator 13. A relay 1 is alternately energized and de-energized to transmit impulses of alternate polarity over the lines 60, 61, two such impulses being transmitted for each step of the switch X. The line relay 113 is operated by the impulse, to effect the operation of the selective switch Y. The inter-train pauses are introduced at points corresponding to the marked contacts of the switch X, and are produced by continued stepping of the switch X while the relay 1 remains inoperative. Detailed description. Transmission of first impulse train. Assuming it is desired to operate the device 169, the key K2 is operated to energize relay 11 and appropriately mark contacts in the banks of contacts associated with wipers 53, 54. Relay 8 also is operated to connect the stepping magnet 12 in series with the impulse, generator 13 in the place of resistance 56. The generator 13 is operated continuously under the control of pendulum-operated short-circuiting contacts 44. When the magnet 12 is in series with the winding 13, it remains de-energized, but pulls up when the winding is short-circuited. When the relay 12 is subsequently de-energized at contacts 44 the switch X is moved one step and the relay 1 is energized over wiper 52 to reverse the contacts 20, 21 and transmit the first impulse. The relay 9 is energized in series with relay 8 over wiper 55 to prevent mutilation of the signal by other control keys. Relays 12, 13 continue to interact to impulse relay 1 and transmit impulses over the line wires, two impulses being transmitted at each step of the switch, until the wiper 53 engages the marked contact when simultaneously with the transmission of the last impulse of the first train relay 6 is energized over the marked contact to maintain relay 1 energized over contact 26. Inter-train pause. Subsequent operations of the magnet 12 operate the relays 2 - - 5 in succession while the. control switch moves two steps. Energization of relay 5 releases the locked relay 6 to release relays 2 - - 5 and open the holding circuit of the relay 1 to initiate the second train of impulses. Subsequent impulse transmission. The second train of impulses is terminated when the wiper 54 arrives at the marked by the key K2., and the relay 7 is thereby operated. The relay 7 opens the circuit of relay 1 throughout the pause measured, in the manner previously described, by the relays 2 - - 5. The third train of impulses is then initiated and transmitted in a similar manner, the train being terminated when sufficient impulses are generated in the third train to complete the total of twenty-seven impulses by the engagement of the wiper 53 with the multipled contacts to energize relay 6 which again operates the pause relays 2 - - 5 to prevent further impulsing in the line wire. The relay 6, however, is not finally de-energized, but is held energized over wiper 53 during its remaining movement. When the wipers reach their normal positions relay 6 is de-energized and relay 1 is released to transmit a final impulse which effects release of operated selectors at the substations. Restoration of the switch at the control station also effects release of the locked relays to restore the apparatus to normal in readiness for the next call. Operation of substation apparatus. Each transmitted impulse advances the stepping switch at station 171 in known manner, and by the momentary energization of the polarized relay 113 at station W advances the switch Y one step. Upon energization of relay 113, relay 101 is operated to energize slow-release relay 102, which holds during impulsing, and stepping magnet 115. At the end of each impulse, relay 113 restores and 101 is de-energized to permit the switch to move one step. At the end of the first train of impulses relay 102 falls back to close a circuit over wiper 140 for a relay 109 which prepares the circuit of the unit to be selected. The second train of impulses operates the switch Y in a similar manner to energize, a relay 111, and prepare a second point in the circuit of the unit 169 to be selected. The third train of impulses operates the switch into such a, position that the selected circuit is completed. As, in the apparatus shown, the switch Y is a 25-position switch and the total number of impulses transmitted is twenty-seven, the switch is moved into the second position from normal to energize a relay 108 and thereby operate the selective device. Release of substation apparatus. The final impulse transmitted after the impulse trains operates the switch a further step to open the circuit of the unit 169 and causes the energization of relay 106, which locks and connects the stepping-magnet 115 to the wiper 138 which cooperates with multiple contacts to return, automatically the switch to normal, in which position relay 106 releases. Locking out unwanted stations. At stations not called, the wipers 140 come to rest at the end of the first train upon contacts which are not associated with apparatus units or signalling devices. All such contacts of each substation switch are multipled together and cause the operation of relays 107, which open the circuit of the stepping magnet 115 to prevent further stepping by the second and third impulse trains until the final releasing impulse is transmitted. Telephone facility. Bridged across the line wires is an ordinary magneto local battery telephone through which conversations may be carried on with a selected substation. Modifications. Although the apparatus shown is adapted for a total of twenty-seven Impulses, any other fixed number may be utilized by correspondingly varying the number of multipled contacts of wiper 53 and effecting similar modifications in the connections to the switches Y at the substations. The control keys, such as K<1>, K<2>, may be replaced by auxiliary contacts upon devices under supervision. Specification 326,252 is referred to.