Patent GB-620710-A (GB)
Title: Remote control installation
IPC: H04Q9/04
Filed: 1946-08-22
Abstract: 620,710. Electric selective-signalling systems. COMPAGNIE ELECTRO-MECANIQUE. Aug. 22, 1946, Nos. 25139 and 25140. Convention dates, Feb. 26, 1943, and June, 8, 1943. [Class 40 (i)] [Also in Group XXXIX] In a remote control system, synchronous distributers at the controlling and controlled stations are stepped by local tuned vibrators released simultaneously over a circuit including synchronizing contacts of the associated distributers. These normally rotate continuously until the command is carried out but if one distributer advances on the other it stops on its synchronizing contact until synchronism is again established. At the control station I, Fig. 1, movement of a switch 20, appropriate to a controlled device D at station II, energizes relay 16 which in turn energizes starting relay 13 in series with 13<SP>1</SP> at station II over distributer contacts 14A, 15A, line wires 1, 2 and contacts 14<SP>1</SP>A, 15<SP>1</SP>. The consequent breaking of the continuous circuits through resistances 12, 12<SP>1</SP> and vibrator coils 4, 4<SP>1</SP>, releases the reeds 3, 31 and the pulsating current from batteries 6, 6<SP>1</SP> energizes stepping magnets 7, 8 and 7<SP>1</SP>, 8<SP>1</SP> to advance the associated distributers 9, 10 and 9<SP>1</SP>, 101 respectively. The energizing circuit of relays 13, 13<SP>1</SP> is broken on the initial movement of the distributors and when a revolution has been completed the holding circuits through coils 4, 41<SP>1</SP> and resistances 12, 12<SP>1</SP> are again established to stop rotation unless the initial release circuits remain unchanged. Consequently, if one distributer is in advance of the other it will stop on its synchronizing contact until the release circuit is again completed through the synchronizing contact of the other distributer. When the wipers reach the appropriate functional contacts 33, 34, a circuit is completed from battery 25 through polarized relay 24, lamp 22 and the line wires to polarized relay 24<SP>1</SP> and battery 25<SP>1</SP>. These batteries are in series but the resistance of lamp 22 prevents operation of the relays while flashing of the lamp at each revolution indicates that D is not in the desired condition. The operator now closes switch 23 and relays 24, 241 operate, the latter energizing the device D. Contacts 20<SP>1</SP>, mechanically connected to D, also change-over whereupon the effective reversal of battery 25<SP>1</SP> opposes battery 25 to de-energize relays 24, 24<SP>1</SP>. The operation of relay 24 releases relay 16 and the distributers stop on their synchronizing contacts. If the device D moves from its set position, contacts 20<SP>1 </SP>change over and the system operates in a manner similar to the above. The operator is notified of the change by flashing of the lamp 22. He can re-set D by closing switch 23 or he can change over switch 20. A detail modification for interconnecting three stations to operate synchronously is described with reference to Fig. 2 (not shown). This also shows the use of an additional synchronizing contact, on each distributer, diametrically opposite the first. The relays 13 and 16 of the arrangement in Fig. 1 are omitted in the modification shown in Fig. 3 (not shown) in which the current normally holding the vibrator coils is opposed by current which flows in the line when a control switch is changed over. It is also proposed to operate these relays by alternating currents obtained from tone generators connected in a closed loop throughout the system. Further modifications include the use of a pair of opposed rectifiers at the controlled station in place of battery 251, which discriminate between the two directions of control current, and the use of two distributer contacts for each device to give greater accuracy in selection. In addition, in order to avoid repeating, at each revolution of the distributors, an attempt to perform a function which is impossible owing to a fault, a condenser may be put in series with the operating circuit whose initial charge is sufficient to operate the relay 24<SP>1</SP> but which prevents further flow of current. As applied to a telephone. intercommunication system (see Group XXXIX), the ringing circuit includes the appropriate selecting contacts but the speech circuits are in parallel and are set up over the synchronizing circuit by a speech transformer bridging contacts which are broken when the receiver is lifted. The invention may also be applied to the remote indication of voltages by connecting the voltage to be measured to the appropriate distributer contact at the remote point and connecting an indicating device, preferably thermionic, to the corresponding contact at the control point. In this case a large capacity across the circuit retains a charge indicative of the voltage during the time that the distributer arm is not on the contact, see Fig. 8 (not shown). A modification of this arrangement enables a voltage at a remote point to be controlled.