Patent GB-687002-A (GB)
Title: Improvements in electrical signalling systems suitable for use in mines or the like
Inventor: PREIST THOMAS PHILIP
IPC: G08B25/14
Filed: 1950-02-18
Abstract: 687,002. Electric signalling systems. AUTOMATIC TELEPHONE & ELECTRIC CO., Ltd. Feb. 6, 1951 [Feb. 18, 1950], No. 4235/50. Class 40 (i). In a mine signalling system destination signals which may need to be displayed throughout a wind are selected by a stepby - step switch which does not respond to "action" signals. Normal operation. Action signals. On the operation of key KSL by the onsetter at a particular level the line relay L in the equipment Fig. I individual to that level at the engine-house operates and is followed by relays C and BA and release magnets SARM, SBRM which allow the uniselectors SA, SB to return to normal. Relay L also rings the signalling bells at the bank and in the engine-house. On the release of the key and line relay a further relay BB pulls up, disconnects the release magnets and connects up stepping magnet SASM. If, however, no further impulse comes in BA and BB fall back but C remains locked over its upper winding and the RAISE lamp connected to the first terminal of SA1 (SA has not been stepped) is lit. In the case of a train of impulses BA and BB remain operated until the end of the train and each operation of L after the first energizes the stepping magnet SASM. At the end of the train BA and BB fall back as before and the selected lamp is lit. On the operation of the winding engine the relays G and F in the common cancelling group Fig. 2 are successively energized whereupon the relay C is unlocked and the display lamps go out. If an impulse is sent with the engine running the switches SA, SB are restored as before and a circuit is made over SA3 to light the STOP lamp LPS. As soon as the engine stops, G, E and C fall back and the lamp is extinguished. When the MEN signal is sent a relay D is operated to give the signal and remains locked while the engine is running and after the engine has stopped if the uniselector SA has not been released. When a signal is received with che engine running a relay J is operated and delays the relapse of G and E when the engine stops until the termination of the signal. This prevents loss of signals and a false RAISE signal if key KSL is still depressed to give the STOP signal when the engine stops. Emergency STOP signal. This is given by operating a relay ES by a special key KESL whereby to light the STOP lamp, the emergency STOP lamp and LEVEL lamp and release a relay SR and relay C. The DESTINATION lamps are extinguished with release of SR and operation of a relay HT with ES also sounds a hooter ESH. On the release of the key KESL the hooter is disconnected but ES remains locked. DESTINATION signals. If there are six or more impulses in the train a relay SSR operated in the sixth position of SA2 in series with C switches over the stepping circuit to magnet SBSM so that subsequent impulses step switch SB. Relay SSR also operates SR which at the end of the train remains locked and lights the LEVEL lamp and the selected DESTINATION lamp and maintains disconnected the release magnet to prevent the release of SB by subsequent action signals. The operation of G when the winding engine starts interrupts momentarily the locking circuit over the lower winding of SR. An alternative locking circuit may be provided at will over a connecting frame DST to keep the lamp lit until the engine stops. Transmitting arrangements for an onsetter with assistants. Only the main on setter can send signals to the engine house and this he does with key KS, Fig. 2, but the key is not effective unless all the assistant onsetters have previously operated their ready keys KS1, KS2, &c. to operate relays 10S, 20S, &c. These relays lock up via emergency STOP keys, KES1. KES2, &c. and light lamps individual to the assistants. When the key KS is rendered effective a lamp LPM at the main onsetters position is lit. The relays 10S, 20S, &c. are unlocked by the change over of G and E at the end of the wind. Emergency STOP keys KES are provided for the head onsetter and each assistant but those of the assistant onsetters can be rendered ineffective by a key KCO which also enables the head onsetter to send signals without the co-operation of the assistants.