Patent GB-191007621-A (GB)
Title: Electric Train Control System.
Inventor: PRENTICE FRANK WYATT
IPC: B61L3/22
Filed: 1910-03-29
Granted: 1910-12-31
Abstract: 7621. Prentice, F. W. March 29. Wireless systems.-In a system in which Hertzian waves are used to control signal-receiving apparatus on trains, a wave wire 40 extends throughout a track block, and is energized by the secondary of a transformer 41 through a switch 49 of a track relay 39 of the next block in advance. The signal-receiving or trainstopping devices on the train are kept out of action so long as the track wave wires, by means of pick-up antennae on the train, are able to maintain the conductivity of a coherer on the train. When less than a complete block separates two trains, the wave wire of the rear block being de-energized by the track relay of the block in front, the signal-receiving apparatus on the rear train is operated. Simultaneously with that operation, the antenna co-operating with the wave wire 40 is superseded by a second antenna positioned to cooperate only with the short wave wires 45 at the block junctions. A train, on receiving a stop signal, has therefore to proceed slowly to the next junction before receiving any indication whether or not the track is cleared. The coherer 2, Fig. 3, on the train comprises a wood block 2 mounted on a shaft and having a cavity containing metal filings. When it is in the upright position shown, the filings are in contact with screws 80. The coherence is destroyed by rotating the shaft, which is carried by a rocking armature 16, Fig. 2, of an electromagnet 15. The circuit of the magnet 15 is closed by a relay 4, which itself is controlled by a relay 3. The circuit 6 of the relay 3 is closed by contacts 17, 18 when the armature rotates into its stable position, and is broken when the magnet rotates the armature from that position. The magnet circuit is maintained after the breaking of the relay circuit 6 by metal sleeves 5, forming closed circuits of low resistance, which delay the release of the relay armatures. By this apparatus, the armature 16 is caused to oscillate and to dwell at that end of each oscillation at which the coherer is, as shown, in a position to cohere. The local circuit of the coherer is completed through a relay 19 which controls a second relay 25. Both relays have metal sleeves 5, and the second one controls the circuit of a brake - controlling magnet 55. The sleeves 5 cause such a delay in the action of the relays that the relay armature 26 does not move to allow the spring switch 28 to open during the period of decoherence when the armature 16 is oscillating, but only when, on its return to the upright position, the coherer does not re-cohere. When, through the absence of waves, the relay armature 26 is released, spring contacts 28 open and break the circuit of the magnet 55. At the same time, a spring contact 32 disconnects the pick-up antenna 30 from the coherer, and a spring contact 33 connects the supplementary antenna 31 with the coherer. When the magnet 55 is de-energized, its armature 56 falls and moves a rod 57 to allow a toggle 59 to bend upwards. A valve spindle 63 is thereby freed, and is pressed outwards by a diaphragm 61 so opening a train valve 66. When the train-pipe pressure has fallen sufficiently, a spring 75 closes the train valve and so prevents the complete application of the brakes. A warning is given to the driver by the blowing of a whistle prior to the automatic application of the brake. The whistle valve 71 is opened by an electro-magnet 67 when its circuit is closed by a switch 23 on the first relay 19.