Patent GB-789330-A (GB)
Title: System for the selective energisation of a number of electrical circuits in accordance with codes punched in a tape
IPC: B61L17/00
Filed: 1955-09-05
Abstract: 789,330. Railway marshalling yards. WESTINGHOUSE AIR BRAKE CO. Sept. 5, 1955 [Sept. 10, 1954], No. 25437/55. Class 104 (1). [Also in Group XXXVIII] Relates to a system for the selective energization of a number of electrical circuits in accordance with codes punched in a tape, and is described as employed in a system for recording on tape railway classification yard storagetrack numbers contained in a switch list, converting the coded punch marks into electrical code pulses, and using the pulses to initiate the setting of the track switches. The storage track information on the tape consists of two consecutive digits representing the track number, for numbers under 10 the track number being preceded by a zero, and the system is capable of selecting a circuit represented by a number from 01 to 99. When the start button SPB is pressed, a start relay IR is energized. which causes start relay repeater IRR in turn to be energized. When SPB is released IR is de-energized and relay RMER is energized to operate a magnet 23 to lift a detent from the driving means of a distributer arm 22 and allow it to be driven through one revolution. As arm 22 begins each revolution, RMER is released and the tape is pulled through reading contacts 21 and positioned so that code marks for the next character may be sensed by the contacts. The contact SPB must be closed and released for each circuit selection. When arm 22 reaches segment 1 and until it leaves segment 3 the tape reading contacts 21 are energized in accordance with the code whereby corresponding tape reading relays TR1 ... TR5 are energized, and number checking relay NCKR will be picked up if the TR relays indicate a numeral in accordance with the code employed. When NCKR picks up a relay SR is energized to prepare a circuit for relay T and the energized relays TR1 ... TR5 cause a corresponding one of the tens digit storage relays 10CR- 90CR to be energized unless the digit is zero in which case no storage relay is energized. Timing relays ETR and BTR hold the CR relay energized for a complete cycle of operations. When arm 22 leaves segment 3, NCKR releases, and when the arm reaches segment 4, T picks up. As the arm reaches the " STOP " segment, RMER is again energized to release the detent and permit the arm to be driven through another complete rotation to read the second digit of the code. The appropriate TR relays are energized on segments 1, 2, 3, and through a front contact of relay T the corresponding unit digit storage relay 1CR ... 0CR is energized and together with the tens digit storage relay selects the appropriate line, relay NCKR being energized if the code is correct. For simplicity only the connections for lines 1 to 29 are shown. When the selector is used with an automatic track switching system, one or more repeater relays may be interposed between the circuit selected and the external circuits to be controlled so that more than one external circuit may be controlled by each of the selected circuits, Fig. 2c (not shown). Energization of NCKR causes SR to pick up and IRR releases. When the arm leaves segment 3, NCKR releases to release the units digit CR relay but relays T and SR remain energized until the arm reaches the " STOP " position and is engaged by the detent, the tens digit CR relay being released when the timing relays ETR, BTR have completed their cycle of operation. The relay NCKR ensures that no selection will take place unless two consecutive symbols indicating numbers appear on the tape. If a mistake occurs in the tape, a sequence checking relay SCKR is energized instead of NCKR and no digit relay is energized. After a period determined by relays BTR, ETR, the system will be cleared of any previous storage, and will then read the next set of marks on the tape without operation of the start button. If an error is made in the preparation of the tape, a character " x " represented by energization of relays TR1, TR4, TR5, is coded on the tape immediately after the error, the front contact a of relay TR1 being arranged by means not described to cancel the previous erroneous information.