Patent GB-139004-A (GB)
Title: Improvements in or relating to electrical signalling systems, such as are used in mines
IPC: B66B19/06
Filed: 1919-02-22
Abstract: 139,004. Automatic Telephone Manufacturing Co., and Green, H. Feb. 22, 1919. Mine signalling systems; order apparatus.-By using all possible combinations in two line-wires of positive, negative, and zero currents, eight different visual signals are given. More signals can be obtained by using a larger number of line-wires. Each visual signal is supplemented by a corresponding number of bell-rings given by repeating the signal currents the required number of times. Means are provided for bringing into action the level indicator lamp, banksman's bell, and the recording-apparatus described in Specification 139,003, and for acknowledging, querying, and cancelling signals. A set of apparatus is provided for each level, with cancelling relays in common. Specifications 18780/14, 118,828, and 118,330 also are referred to. Transmitting apparatus, Fig. 1. This comprises a wheel 4 by which a commutator drum 3 in a water-tight casing can be set to one of eight numbered positions, each corresponding to a different combination of positive, zero, and negative currents, which can then be transmitted over the two line-wires A, B, Fig. 6, by depressing the handle 16. The eight positions of the handle 4 are made definite by a spring bolt engaging notches in a disk 26. The brushes 6, 7 are re spectively joined to the negative and positive terminals of a split battery, the middle of which is earthed. The commutator is set to connect these brushes to the brushes 5, 8 in one of eight different combinations. When the knob 16 is depressed, the brushes 5, 8 are connected through two terminals as 22 (to which they are permanently joined) to two terminals as 18 which are respectively joined to the line-wires A, B, a selected combination of currents being thus sent over these wires. Simultaneously, through two spring contacts as 24, current is sent to energize one or both of two self-locking electro-magnet relays which light up the lamp 15. This lamp illuminates a signal number in a dial 11 attached to the handle 4, but not till this handle has been set and the signalling-currents sent out. The line B is normally connected through a brush 18 to a terminal 20 and so to a relay which sounds a bell when the banksman acknowledges a signal by depressing the switch 110, Fig. 6. A query signal sent similarly over the A line via the switch 39 sounds an electric horn. Receiving-apparatus, Fig. 6. Polarized relays 37, 38 are so arranged as to energize one or a pair of the relays 47 - - 50 on receipt of the signalling-currents. Each of these four relays has three armatures as 67, 68, 69 so interconnected that only one of the eight relays 52 - - 59 is energized for each possible combination of line currents. The relays 52 &c. are self-locking through their front armatures 76 &c., and they illuminate the required visual signals through their rear armatures 82 Rc.. When the magnet 52 is energized, the " stop " or " raise " signal is given according as the engine is running (relay 80 energized) or stationary (relay 80 de-energized), as described in Specification 118,828. The electromagnets 84 &c. are for recording the signals as described in Specification 139,003. The relay 51 is energized whenever a signal is received, and it rings the engineman's bell 87 and operates the level indicator relay 88 and banksman's bell 89. The visual signals and level indicator lamp are extinguished to cancel a signal when the engine stops cr starts by means of the quick-acting cancelling-relay 95 (which is energized so long as the engine is running) and the slow-acting relay 80 (which is energized by the relay 95). as described in Specification 118,330. The remaining apparatus shown is described in Specification 139,003.