Patent GB-360979-A (GB)
IPC: G08B25/00
Filed: 1930-08-15
Abstract: 360,979. Fire-alarm systems. AUTOMATIC TELEPHONE MANUFACTURING CO., Ltd., Strowger Works, Liverpool. Aug. 15, 1930, No. 24502. Convention date, Sept. 14, 1929. [Class 40 (i).] In a fire-alarm system, when a signal is transmitted from a fire-alarm box to a district office, the number of the box is transmitted from the district office to a supervisor's position whence it is retransmitted to the district office and to all other district offices in the system. In each case the number is transmitted twice, lighting two display indicators thus providing a check on the correctness of the transmission, whilst a third transmission, over separate wires and in a different code, is used to record the number of the calling station on a tape, these pulses also sounding the number on a gong. For the normal number transmission, switches at the transmitting and receiving ends are stepped in synchronism by pulses over one of a pair of conductors whilst the code is transmitted by pulses over the other wire operating storage relays. Telephone transmission between the firealarm box and the supervisor's position is provided and provision is made for signalling faults on the line circuits to the district office. Alarm calls may be received by the supervisor over a telephone circuit (not shown) whereupon a number (either predetermined or of the fire-box nearest the place of the alarm) may be set up on a key set whence it illuminates displays at the supervisor's position and is transmitted to the district offices in the usual way. Connection of calling station. To originate a call the contacts 5, Fig. 1, are opened inserting the resistance 6 in the line circuit. Relay 40 at the district office de-energizes and relay 30 remains operated. Alarm lamp AL lights and relay 25 pulls up operating the audible signal SG. Relay 20 energizes and locks, completing a circuit over 247 for relay 200, Fig. 2. Magnet 210 of the sequence switch SS energizes and, by self-interruption, steps the wipers 215, 216. When the calling circuit is reached relay 205, which has been shorted by ground on 215, pulls up in series with 210 and relay 10, Fig. 1, energizes from earth on 216. Relay 10 grounds all its armatures which, through the connecting block CB, mark terminals in the bank of the sender SN. Transmission of number to supervisor's position. When relay 200 energized, relay 220 pulled up and relay 290 operated. Relay 280 energizes and the trunk line 233, 234 is switched through to the sender SN. Relay 285 releases, lighting lamp TCL. At the central station normally energized relays 500, 505, Fig. 5, release, lighting lamp TL and energizing relay 540 to sound buzzer B. Ground is removed from conductor 580, marking the calling circuit in the bank of the finder switch F whilst ground placed on conductor 544 energizes relay 600, Fig. 6. Relay 600 completes a self-interrupting circuit for magnet 615 to step the finder wipers and when wiper 616 reaches an unearthed contact the hunting stops and relay 605 energizes (relay 610 having pulled up when 600 operated). Relay 605 opens the circuit of 610 and this relay relapses switching the trunk circuit through to the receiver R1, Fig. 7. Relay 605 also completes a circuit over conductor 545 for 1005, Fig. 10, which relay locks up, and a circuit over conductor 670 for 700. Relay 700 earths conductor 674 which extends over wiper 617 to light lamp EL, Fig. 5, and energize relay 510 to switch the trunk circuit through to the receiver R1. Before relay 610 releases the ground on wiper 618 is extended over 542, 233 to relay 235 in the sender SN, Fig. 2, and this relay locks and energizes 240. Relay 245 pulls up completing two circuits ; one for magnet 260 to step wipers 270, 271, 272 and the other over conductor 234 to energize relay 740. Relay 245 and magnet 260 interact to step wipers 270, 271, 272 and the pulses are repeated by relay 740 to magnet 750 of the receiver R1 stepping wipers 760 .. 764 in synchronism with wipers 270, 271, 272. It will be remembered that the relay 10 has marked certain terminals in the bank of switch SN and as wiper 270 reaches these marked terminals the earth is extended over conductor 233 and wiper 762 to energize corresponding relays in the storage group DS1. The number of the fire-box shown is 249 and to transmit this number conductors 60 .. 64 are marked by relay 10 resulting in relays 800, 820, 840, 850, 860 being energized and locked up to conductor 558, the relays on locking connecting earth to conductors 770, 772, 776, 777, 782 respectively and illuminating the number 249 on the display, Fig. 8. When wiper 271 of SN reaches contact 274 relay 255 energizes followed by relay 250. The circuits of magnet 260 and relay 245 are opened but a self-interrupting circuit is completed for magnet 260 to step the switch through the rest of the first half revolution. When wiper 271 reaches contact 276 relay 255 relapses followed by 250 and the sender circuit is in the same condition as before the signal was received. Similarly in the receiver R1 relay 720 is energized from ground over 764 and relay 730 pulls up. The magnet 750 steps the switch automatically until wiper 764 reaches contact 767 when 720 de-energizes. The sender SN is again operated to send the code to the receiver R1 and as 762 is revolving out of the contact bank whilst 761 is moving over bank terminals, a second storage relay group is set to the calling number and a second display is illuminated. When 271 again reaches contact 274, relay 255 energizes, followed by 250, relay 245 relapses and the self-interrupting circuit for 260 is recompleted. When wiper 272 reaches contact 275 relay 225 pulls up and remains energized when the switch regains its home position. Similarly when wiper 763 reaches contact 765, relays 720, 730 energize and magnet 750 moves the wipers automatically until the switch reaches its home position whereupon relays 720, 730 de-energize. Before relay 720, which is slow to release, relapses circuits are completed from earth on wiper 760 firstly to relay 710 and secondly over conductor 547 to relay 1010 and to relay 930. Relay 710 opens the circuit of relay 510 disconnecting the junction from the finder switch and allowing relay 505 to re-energize. Relay 600 relapses releasing the finder switch. When the sender SN regained its normal position, relay 225 remained energized, shunting down relay 20 and energizing relay 230, which locks to conductor 238. Relays 240, 235 release and relay 200, still energized over the start circuit 247, falls away. Relay 10 de-energizes removing the marking from the banks of switch SN. Relays 220, 290 release, the latter relay connecting the line circuit 233, 234 to receiver R2. Transmission of number back to district office and to all other district offices. Relav 290 completes a circuit to energize 300, removing ground from the first 16 contacts of the banks wiped by 352 and 353 and completing a holding circuit for 225. When 1010, Fig. 10, was operated a circuit was completed over 549 for 655 in transmitter T. Lead 549 is commoned to all transmitters as T and the relays 655 in each pulls up. Relay 650 energizes slowly and, before it operates its armatures, a pulse is transmitted over 234 to energize 305, Fig. 3. Relay 305 locks in series with 310. When 650 is fully energized, 635 pulls up completing a circuit from ground on 549 to relay 630. Relay 630 energizes magnet 660 and interaction takes place to step wipers 665, 666, 667. Each time 630 energizes it connects ground to conductor 550 to energize 325 and this relay repeats the pulses to magnet 340. The switches T and R2 operate exactly as was described for switches SN, R1 resulting firstly in relays 400, 420, 465, 470, 480 in relay group DS3 becoming energized to illuminate a display and secondly in a second storage group DS4 being operated to provide a checking indication. After the second transmission, relay 645 pulls up followed by 640 which completes a circuit over 552 to light lamp OL, indicating that transmission to all district stations has been completed. Provision of permanent record at central and district offices. While the transmission has been taking place the code sender CS, Fig. 9, has been operating. It will be remembered that when Rl reached its home position 1010 energized completing a circuit over 554 for 930, Fig. 9. Relay 920 energizes and locks and relay 960 pulls up slowly. Relay 960 prepares a circuit for slow relay 970 and these two relays interact completing a circuit, every time 970 energizes, for magnet 980 to step the wipers 990 .. 995, and for relay 905 to energize. Each time 905 pulls up, 909 in the central station and 360 in each of the district stations release, enabling the perforating magnets PR, PR1 to release and perforate the paper strip and allowing alarms G, G1 to sound. A hole is thus punched in the tape at each of the stations each time relay 970 energizes. The connections to the bank contacts of 990, 992 and 991, 993 are such that both wipers find earth only when the number of steps made by the switch is equivalent to the digit stored. When wiper 990 finds earth relay 950 pulls up and, if this relay is energized when 992 reaches an earthed contact, 940 responds opening the circuit of 960 to stop further pulses being recorded and completing a circuit for 980 to step the wipers to the next home position. Relay 940 releases and relays 960, 970 recommence interaction to record the next digit. The three digits of the calling office are thus recorded by perforations in the tapes at the central and all the district offices and the number of the station is tapped out on the gongs G, G1. When wiper 995 reaches contact 989, relays 900, 910 operate and lock up, completing a circuit to energize relay 1015. Relay 1020 energizes, releasing 1005 and relay 930 de-energizes, breaking the circuit of 960. Relay 940'pulls up allowing the switch CS to return to its home position. Rele