Patent GB-191503841-A (GB)
Title: Improvements in Electric Step by Step Signalling Apparatus.
IPC: B66B19/06
Filed: 1915-03-10
Abstract: 3841. Sterling Telephone & Electric Co., Bell, F. G., and Barclay, H. W. March 10. Mine signalling systems; order apparatus. - In a system employing a stepby-step indicator, applicable to mine signalling, the signalling-key is so constructed, and circuits are so arranged, that the indicator is reset to cancel a previous signal when a fresh signal is started, if the key has been restored to its original position, but cannot be reset if the key has not been so restored. The key may be of the kind described in Specification 13,062/14. When several stations, such as the various levels of a mine, signal to a common receiving-station, such as the engine-room, the resetting is effected from any of the stations. Visual signals may be provided to indicate which particular station is signalling. At each station may be provided a check signal operating in unison with the signal at the receiving - station, and a signal operated from the receiving-station to request repetition of a signal. In one form, a single bell at each station serves both functions, giving a single-stroke action as a check signal, and a trembler action to request repetition of a signal. The indicator may be a simple pointer 26 moving over a dial or an arm carrying a contact touching a succession of contacts to close the circuits of signalling-lamps or other devices. The pointer 26, in its zero position, holds open a contact 18, which is closed in all other positions of the pointer. This contact controls the release magnet C of the indicator and also, when provided, the signals indicating which station has signalled. The signalling-keys K<1>, K<2>, K<3>, in their normal position, hold open contacts 2, but when raised to give signalling - impulses by closing contacts 1, the contacts 2 are allowed to close. Each station has a relay M', M', M<3> with an operating-winding 22 and hold-up winding 23. Relays R<1>, R', R<3> and an indicator electro-magnet I are common to all the stations. When contact 1 is closed at anv key, say K<1>, a circuit is completed from negative through winding 22 of relay M' and relay R' to positive. Armature 25 of relay R<1> completes at contact 5 a circuit over the magnet I, through back contact 13 of relay R<3>. The pointer 26 thus moves one step, closing contact 18. The hold-up circuit 23 of relay M' is thus completed through contacts 3, 18, and a circuit is also completed through a lamp L<1> indicating the level or station which is signalling. The relay R' also completes a circuit from negative through the signalling-bell B over contacts 6, 13 to positive. Alrernatively, the circuit may pass to pos tive direct from contact 6. The relay R' also completes a circuit through winding 28 of relay R<2> over contacts 5, 13, whereupon the relay R<2> completes its hold-up circuit through winding 29 and contacts 8, 18. Relay R' also completes the circuits through the windings 30, 31 of relay R<3>, which is differentially wound, so that its armature is not attracted. When contact 1 is broken bv drawing back the key K', relay R<1> is de-energized and releases its armature, but the armature of relay M<1> is held up by the winding 23, and lamp L' remains alight. If contact 1 is again closed, relay R', electro-magnet I, and bell B are again excited as before, and the pointer 26 moves another step. This can be repeated for the required number of signalling impulses. When the key K<1> is allowed to fall, opening contact 2, circuit through the winding 31 of the relay R<3> is broken, so that the armature is attracted, making another break at contact 11 in the circuit of winding 31, and closing contact 12. A circuit is thus ready to be completed through the release magnet C when any of the contacts 2 is closed by raising a signalling-key, passing from positive over contact 18, winding C, conductor 32, contacts 12, 10, and any of the contacts 2 to negative. Thus, when any signalling-key is subsequently raised to send a signal, pointer 26 returns to zero. This opens contact 18, extinguishing the lamp L<1> and breaking the relay circuits 23, 29, 30. Mere lifting of a signalling-key thus resets the indicator, so that a signal may be cancelled without actually sending another signal. A modified arrangement is described in which closing of contact 1 is necessary to reset the indicator. Each signal station may have a signal bell SB<1>, SB<2>, SB<3> in parallel with the bell B, or the circuits may be arranged so that only the bell at the signalling station rings with the bell B. Bells RB', RB<2>, RB<3> may also be provided, respectively controlled bv keys RK<1>, RK<2>, RK<3> and relays RR<1>. RR<2>, RR<3>, whereby the receiving station may request repetition of a signal, the hell ringing continuously until the signalling key is raised to repeat the signal. An arrangement is also d-sc ibed whereby a single bell replaces the two bells at each station, and acts as a single-stroke bell when ringing in conjunction with the bell B, but placed in circuit with a trembler at the receiving-station when repetition of a signal is being requested. The signals may be obliterated automatically from the engine-room, for example by a contact closed by the engine when the signal is being complied with, or by hand, by a key RK closing the circuit through the magnet C.