Patent GB-339308-A (GB)
Title: Improvements in electrical signalling apparatus
IPC: B61L25/04
Filed: 1929-09-05
Abstract: 339,308. Relay Automatic Telephone Co., Ltd., British Power Railway Signal Co., Ltd., and Inman, T. M. Sept. 5, 1929. Selective signalling systems.-In an electrical signalling system comprising means for setting up signals relating to events occurring at a station and means for transmitting the signals to a second station, means are provided whereby, in the event of a signal not having been set up for transmission, operation of the transmitting means causes another or substitute signal to be transmitted. The invention is described as applied to railways for use in signalling, from one cabin to another, descriptions of passing trains, the information being transmitted in the form of groups of impulses representing numbers. In the construction shown, each train is represented by a number of three digits, each digit being transmitted through the medium of a device termed a digit holder, which contains relays operated selectively in accordance with the digit chosen. The indications are displayed on three devices termed, respectively, the last train holder, the last-but-one train holder, and the last-but-two train holder, and are transferred to adjacent holders or cancelled in accordance with the movements of the trains. The keys 1 to 9 and 0, Fig. 4, for setting up the signals are connected, as shown, to six wires, the sixth wire BW being under the control of a relay K6C which is connected to keys 6 to 0 to distinguish their operation from that of keys 1 to 5. The wires are grouped together in a cable 40 which, by means of a digit switcher including relays DSH, DST, DSU, is connected to parts of a cable 42. These parts are associated with cables 42, 32<1> and 43 forming part of a hundresd-digit-holder, a tens-digit-holder and a units-digit-holder respectively. The arrangement is such that upon operation of a key, relay DSH operates to connect the key tq cable 42 of the hundreds-digit-holder. The relay is released when the key is released and when a record key is pressed relay DST operates to connect the second key to cable 42<1> of the tens-digit-holder. Similarly a third key, when operated, is connected .to the cable 43 of the units - digit-holder. The cables 42, 42<1>, 43 terminate in contacts of relays, six to each digit-holder. In the hundreds-digit-holder, Figs. 1 and 2, relay HD1 is operated if either of keys 1 and 6 is pressed, relay HD2 if either of keys 2 and 7 is pressed, and so on, relay HD6 being also operated if any of keys 6 to 0 are pressed. The relays of the tens-digit-holder and units-digit-holder are similarly operated. These digit-holder relays are also provided with contacts preparing circuits for three sets of cables viz., cables 10', 20, 30 adapted to be associated with an impulse counter, cables 25, 25<1> 35; adapted to be associated with the train holders and cables 2x, 2x<1>, 3x, for association with a next-train display panel, if one is provided. Setting up and transmitting signals corresponding to an identified train. Assuming that the operator at a cabin wishes to set up and transmit to another cabin the number 642 indicating the passage of a particular train, the first presses key 6, Fig. 4, whereby a circuit is completed from earth at contact 7 of relay P (Fig. 1) through wire K34 and contact 1 of key 6 to negative at relay K6C. A parallel circuit through contact 2 of key 6 and wire 8 is also completed. Relay K6C operates at contact 2 to control operation of the digit switcher and at contact 1 connects earth to wire BW. The digit switcher connects wires B, BW in cable 40 to corresponding wires B, BW in cable 42 of the hundreds-digit-holder, causing relays HD1, HD6 to operate. These relays lock up and operate relay HH which opens contact 1. The operator releases key 6 and presses key 4. The digit switcher releases relay DSH and energizes DST, whereby contact 3 of the relay TN4 of the tens-digit-holder is connected to wire Br (Fig. 4). TN4 operates and locks up causing the energization of relay TH, which opens contact 1 and closes contact 2. Key 4 is then released and key 2 is pressed whereby relay U2 of the unitsdigit-holder is operated. This relay locks up and causes operation of relay UH which opens contact 1 and closes contact 2. Since relays HH, TH, and UH have opened their contacts 1 earth is removed from wire K34 so that further operation of the keys produces no effect. The number 642 is now held ready for transmission by relays in the digit-holders. In order to transmit this number to the train holders and to the distant station the key SK, Fig. 4, is pressed either by the operator or by a treadle operated by the train designated by this number. A circuit is then completed for relay L. If the receiving apparatus at the distant station is ready to receive a description a circuit is complete for relay LT, which together with relay L acts to complete a circuit for relay SX1. This relay at contacts 2, 7, connects the line wires LA, LB, Fig. 4, to the lines LA, LB shown in Fig. 1, and at contact 1 connects negative to branch S47<1>, Fig. 7, of wire S45 so that a circuit is complete through relay CH10, Fig. 7. This relay operates and opens a holding circuit for relay LC3 and any operated relays in the last-but-two train holder. The description in this holder is therefore removed. The release of relay LC3 opens the circuit of relay CO3 which at contact 4 breaks the circuit of relay CH10. A circuit is now complete through windings of relays CH7, CH8, CH9 which operate and extend cables 67 of the last-but-one train holder, Fig. 6, to the cables 70 of the last-but-two train holder whereby circuits. from operated relays in the former holder are completed to corresponding relays in the latter holder. These latter relays lock up through a circuit including relay LC3 which at contact 1 opens a circuit for relay LC2 and the operated relays of the last-but-one train holder. The description is thus transferred from the lastbut-one train holder to the last-but-two train holder. Similarly a. description is transferred from the last train holder to the last-but-one train holder. The cables 50 in the last train holder are connected, through the operation of relays CH1, CH2, CH3, to the cable 25. A circuit is then complete from earth at contact 6 of relay HD6, Fig. 1, to wire BW in cable 50, Fig. 5. A further circuit is completed from contact 6 of relay HD1 to wire B in cable 50. Relays LH1 and LH6 therefore operate locking up through relay LCX. In a similar manner a circuit is completed from contact 8 of relay TN4 to a wire in cable 50, Fig. 5, whereby relay LT4 operates, locking up through relay LCX. Similarly also relay LU2, Fig. 6, operates and locks up through relay LCX. The relay LCX closes a circuit through relay S which operates to energize relay P, the latter relay, at contact 6, connecting negative to wire N of the transmitting apparatus, Fig. 1. This has the effect of closing a circuit through the impulse relay I and closing parallel circuits for all BK relays in an impulse counter shown in Fig. 1. A circuit is therefore closed for relay DM1 which locks up. This relav connects cable 10<1> to cable 10, at contact 2 completes a circuit for relay DMX1, at contact 3 opens a short circuit across lines LA, LB, and at contact 6 connects earth to relays MK. DMX1 closes a circuit for relay DMX2. The action of relays P, DMX1, DMX2 in conjunction with relays INE2, INT2 causes intermittent interruptions of the earth contact to relay I, producing impulses which cause operation of the MK relays in sequence and the release of the corresponding BK relays. Relay I also interrupts at contact 2 the continuity of the line circuit and thus delivers impulses to the distant station. When six impulses have been delivered to the impulse counter, relay BK6 is released and a circuit is completed from wire N through front contacts of relays BK0 to BK7, and back contact of relay BK6 to wire BW in cable 10 and, by extension to cable 10', through contacts 2 of relays HD1, HD6, through relay DMC1 to earth at contact 6 of relay S, Fig. 3. Relay DMC1 operates and locks up. Contact 4 is opened thereby opening the circuits of relay DM1 which at contact 6 releases any MK relays that may be operated. All BK relays again operate. Negative from wire N is then connected to relay DM2 which associates the impulse counter with the tens-digit-holder. Counting again proceeds until the fourth impulse has been delivered, whereupon relay DM2 is released and the impulse counter is again restored to zero position. Relay DM3 is then operated to associate the counter with the units-digit-holder. Counting again takes place until two impulses have been delivered, the counter again returning to zero position. A circuit is completed through relay TR by way of contacts 3 of relays DMC3, DMC2, DMC1. Relay TR at contact 1 opens the holding circuit of relay S which releases relay P removing negative from wire N whereby the apparatus shown in Figs. 1, 2 and 3 is restored to normal. Before relay P releases, relay TR at contact 3 closes a circuit through relay LC1, Fig. 5, which causes energization of relay CO1. This relay at contact 1 completes a circuit through contacts 3 of relays LH6. LH1 to lamp 6 in the last-train displayer. Parallel circuits are completed through contacts 5 of relays LT6, LT4 to lamp 4, and contacts 5 of relays LU6, LU2, Fig. 6, to lamp 2, so that the the last-train displayer indicates the number 642. Impulses corresponding to the number have also been transmitted to a distant station over wires LA, LB. Transmitting signals corresponding to an unidentified train. Means are provided whereby, if the operator omits to set up on the digit-holders the description of a train, a certain number is transmitted to the last-train holder. When the key SK is operated a circuit is complete from earth through contact of relay DMC3, Fig. 3, contact 8 of relay SX1, Fig. 4, wire U14, contact 7 of relay S,