GB1239131A - - Google Patents

Abstract

1,239,131. Automatic train control. WESTINGHOUSE AIR BRAKE CO. 25 March, 1969 [26 March, 1968 (2)], No. 15444/69. Heading B7N. [Also in Division H4] In an inductive signalling arrangement for indicating when two objects which are relatively movable along a predetermined path are in close proximity a coil 16 on one object transmits a frequency f supplied by a generator 23 and co-operates with coils 42, 43, 44 arranged as shown on the other object, the coil 42 comprising two balanced connected sections to reduce the effects of interference. The outputs of coils 42, 43, 44 are supplied to a logic unit 51, Fig. 4, which includes filters 53, 54, 56 tuned to the, frequency f 1 and connected to an AND gate 71. When the two objects are in correct alignment, the signals produced by coils 42, 43, 44, i.e. coils No. 1, No. 2 and No. 3 are as shown in Fig. 5, with coils No. 1 and No. 3 showing maximum signals 105, 110 respectively and coil No. 2 a zero output 103. Just prior to this position, the outputs 100, 106, 107 applied to the gate 71 to cause a monostable 73 to be operated to supply a pulse 109 to a second AND gate 78. When the null position 103 is reached the output from gate 71 ceases but signals 105, 110 are supplied to the gate 78 and signal 103 is supplied via an inverter 77 to that gate so that an output pulse is produced on lead 79. An arrangement is described, Figs. 6 and 7 (not shown) for controlling a railway train, in which three coils transmitting frequencies f 1 , f 2 , f 3 respectively are spaced along the track the last coil being placed adjacent a station at which the train is to stop. Similar circuitry to that shown in Fig. 4 is used but is modified to be responsive to the frequencies f 1 , f 2 , f 3 to control the speed, braking and stopping of the train.