Patent GB-328031-A (GB)
Title: Improvements relating to apparatus for the electric transmission of indications, such as train descriptions and the like
IPC: G05D3/12
Filed: 1928-12-11
Abstract: 328,031. Peter, L. H., Challans, E. W., and Westinghouse Brake & Saxby Signal Co., Ltd. Dec. 11, 1928. Selective signalling - - apparatus. - In a train describer in which a number of train descriptions are successively transmitted and are exhibited or recorded at the receiver in the order of receipt, a follow-up element at the receiver is employed actuated by a motor under the control of a polarized relay 10 and a pair of non-polarized relays 15, 16. Fig. 6 shows transmitting and receiving resistances 1, 8 arranged in the form of a Wheatstone bridge fed through rectifiers 74, 75 from an alternating supply in which the current supply circuit is normally interrupted at the receiver but is completed on the receipt of a signal by slow release relay 78. The polarized relay 10 in the diagonal of the bridge controls relays 15, 16 controlling the motor M. When a balance is obtained relay 10 is de-energized and the de-energizing of the magnet 21 causes braking mechanism to be operated. The de-energization of relays 15, 16 also causes the printing magnet 29 to be operated under the control of relay 34, which is de-energized by the printing-magnet opening-contact 36. In a modification, Fig. 5, the transmitter is provided with a relay 65 arranged to de-energize the. transmitting resistance. 1 when a balance is obtained. The energization of the transmitting resistance is effected by a plunger 67 and relay 66 which may in addition control an illuminated indicating device 72. The transmitter may comprise a pointer arranged on a plunger which is provided with a locking member which is released only when the transmission is completed. The receiver may comprise relays arranged to prevent adjustment in response to a transmission until the printing of the record is effected. Fig. 8 shows modified forms of bridge impedances for use with an alternating supply in which the impedances are. so arranged that the drop in voltage between adjacent contacts is increased by displacing the phase of the voltage drops across the elements. In a further modification (Fig. 10 not shown) the bridge impedance comprises resistances and condensers arranged in circular form with the alternating voltage applied to a diameter so that rotation in one direction only is necessary and the number of contacts for a given voltage is doubled. The detecting device for alternating current may comprise a.n alternating current relay, or a polarized relay fed through a rectifier, or a thermionic valve with a relay in its anode circuit. Recorder construction. The printing magnet 29 operates a hammer 25 to imprint on the record strip 23 an impression of the type on the drum 22 controlled bv the motor and effects the feed of the strip through pawl 37 and disc 38. A cancelling plunger is provided to move the carriage 43 upwards. Additional time - controlled clockwork drums may be provided one to obtain a record of the receipt of a train description and another a record of the time when the cancelling plunger is depressed. The invention is also applicable to transmitting and preparing lists of goods wagons for use in goods-marshalling yards.