| 摘要 |
529,990. Selective signalling. - WESTINGHOUSE BRAKE & SIGNAL CO., Ltd. May 31, 1939, No. 16000. Convention date, July 19,1938. [Class 40 (i)] In a remote control and supervisory system especially for train control from a central office; the control impulses and indicating impulses are sent over separate circuits and are alternately of opposite polarity the transmission of a signal over one circuit operating to prevent the transmission of a signal over the other circuit. At the control office a master relay OM is energized when a control code is to be transmitted and its contacts b, h connect the line circuit X1, X2 to the battery 9 and its contact j opens the indicating circuit so that the latter is put out of action. The transmitter relay OT operates pole-changing contacts b, d and the duration of the impulses thus applied to the line X1, X2 is controlled by the polarized relay OR operating a change-over switch a connected to the coding unit, Fig. 2. The starting key SK is closed on the unit corresponding to the station to be called, which is identified according to the code used by three long impulses and four short impulses acting upon stepping relays 01 ... 08, corresponding relays at the station being synchronously operated. The unit shown corresponds to code 234, the second, third, and fourth impulses being long. This coding is effected by controlling the reversal of the transmitting relay OT by a holding circuit or by a byepass circuit closed by slow-release relays OL1, OL2 to operate only when the stepping relays 02, 03, 04 pickup. When the remaining stepping relays pick up the reversal of the relay OT is not delayed and short impulses result. At the station corresponding to the code, the stepping relays 2, 3, 4, Fig. '3, are caused to respond by connecting thereto relays F, G, S. The control code is transmitted by a second operation of the stepping relays, a repeat relay OCR picking, up on the second operation of relay 01. Finally a delivery relay D picks up to operate the controlled devices at the station. When an indicating signal is sent from the station it is initiated by the picking up of a relay ST and the code is transmitted in a similar way to the control signal, the corresponding panel at the control office being selected by the connection to the stepping relays 02, 03, 04 of relays 2F, 23G, 234S. Finally, relay 16 picks up and de-energizes the relay M and restores the lines to normal. For distant stations one or more repeater stations may be interposed as shown in Fig. 1. The general operation of the system is similar to that described in Specification 415,787. |
