Patent GB-116426-A (GB)
Title: Improvements in or relating to Electric Signalling Systems, more particularly for use in Mines.
IPC: B66B19/06
Filed: 1917-09-15
Abstract: 116,426. Automatic Telephone Manufacturing Co., and Remington, C. Sept. 15,1917. Mine signalling systems; order and order-type apparatus.-In a mine signalling system the signals from the several levels are recorded upon a single indicator; while each level is provided with a lamp at the winding station to indicate the level from which the signal is being received. Each level is provided with a busy lamp, a signalling key and a relay which is energized through the back contacts of the other level relays upon the depression of the key. The first depression of the signal key energizes the operating winding of the relay, the armatures of which are operated to close the circuit of the master relay, to energize the hold-on coil of the relay through the level indicator lamp and the cancelling relays, to break the circuits of the operating windings of the other level relays, and to place the signal keys of these relays together with their busy lamps across the battery. Subsequent depressions of the signal key energize the master relay to control the indicator in the manner described in Specificatior 18780/14. Construction. The drawing shows an arrange. ment for three levels, the first of which is pro. vided with a key 1, busy lamp 4, and relay 7; the second with a key 2, busy lamp 5, and relay 8; and the third with a key 3, busy lamp 6, and a relay 9. The relay 7 is provided with an operating winding 10, a hold-on winding 13, an armature 23 controlling the circuit of a master relay 26; an armature 30 controlling a circuit containing a level indicator lamp 32, a holdon winding 8, and cancelling-relays not shown, and armatures 23<1>, 30<1> which in the normal positions shown are in the circuits of the operating windings of the relays 8 and 9, and which in their attracted positions partly complete the circuits of the busy lamps 5 and 6 respectively. The relays 8 and 9 are provided with similar windings and armatures. Operation. When the signal key 1 of the first level is depressed, the operating winding 10 of the relay 7 is energized as follows :-Positive terminal of battery B, key 1, lamp 4, lead 16, armature 19 and back contact 20 of relay 9, lead 16<1>, armature 21 and back contact 22 of relay 8, lead 16<11>, winding 10, armature 23 and back contact 24 of relay 7 to negative terminal of battery B. The relay 7 then operates to close the circuit of the hold-on winding 13, level indicator lamp 32 and the cancelling relays, not shown, at the contacts 30, 31; to close the circuit of the master relay 26 at the contacts 23, 25, to open the circuits of the operating windings 11 and 12 of the relays 8, 9 and to connect the leads 17, 18 of the keys 2 and 3 to the negative side of the battery B. Further depressions of the key 1 energize the master relay 26, but during the signalling period, the lamp 4 is prevented from glowing since it is connected in series with the high resistance operating winding 10. If however either or both of the keys 2 and 3 in the other levels are operated while signalling is occurring at the first level, the lamps 5 or 6 or both glow since they are connected directly across the battery B through the operated armatures 23<1>, 30<1>.