Patent GB-572208-A (GB)
Title: Remote control and indicator equipment
IPC: G08B21/00
Filed: 1943-10-22
Abstract: 572,208. Signalling systems. STANDARD TELEPHONES & CABLES, Ltd. (International Standard Electric Corporation). Oct. 22, 1943, No. 17421. [Class 40 (i)] [Also in Groups XIX and XXX] In a system in which the condition of a track relay at each of a number of stations is signalled in succession to indicating apparatus, a permanent record of the condition of the indicating apparatus is made periodically and shows the progress of all the trains on the track. Signalling arrangements, Figs. 1 and 2. On the operation of a starting key, a switch CH1 moves on to its first terminals and a circuit is completed by a sequence-switch for a pair of relays (not shown), for controlling a relay S1 connected respectively to + and - battery over line wire A, one or other of rectifiers a, b, according to the condition of a track relay P, and a relay V1 which locks and connects a relay T1 to the wire B to which + or - battery is connected at the central station according to the number of the station being tested. Relays T1, T2 &c. are polarized in opposite directions in successive stations by rectifiers. T1 pulls up and is mechanically latched and when V1 is released by the moving on of the control switch, the line is extended to the second station which is tested in like manner. The condition of all the relays P is thus reproduced by the relays S which control lamps. At the final station, the relapse of Vn when the switch CH moves to its last terminals t connects a source of A.C. to the wire A to energize F which connects an A.C. source to the wire B to operate unlatching magnets R1 ... Rn which restore all the relays T. Recording arrangements, Fig. 3 and Fig. 4 (not shown). The recording sheet is driven uniformly in the direction of the arrow and the pen P which is normally out of contact is driven transversely in a number of steps, each of which corresponds in length to the length of the particular track section, a mark being made for each occupied section so that the record shows to scale the positions of all trains in relation to the whole track. In the arrangement shown in Figs. 1 and 3, when switch CH2 moves on to its first terminals, a circuit is made over one or other of its first two wipers, which are connected together and to a wire 5 by means not shown in a circuit SW2. Whatever the condition of the first tell-tale relay S, therefore, a circuit is made for a motor M which drives the recording pen. Impulses are sent back from an interrupter d1, d2 driven with the pen over a third wiper of CH2 to a point on a counting chain which corresponds to the length of the first track section. The chain builds up to the right and when the last relay C<1> operates, the motor circuit is interrupted and a circuit is made for a sequence switch (not shown) which causes the unlocking of the counting chain, and the connection of the first wiper to the stepping circuit of CH2 and the second wiper in succession to the wire 3 leading to the pen control magnet C2 and to the stepping circuit of CH2. If the corresponding tell-tale relay S is energized the switch steps on at once. If the relay is not energized, the switch steps on after C2 has been energized to make a mark on the record sheet. Similar operations take place with CH2 on subsequent terminals. On its last terminals, the switch makes a circuit over wire 4 for release magnet e1 which allow the pen carriage to be restored to normal, whereupon a circuit is made over contacts h and wire 5 for interrupting this circuit. In a modification, Fig. 4 (not shown), the pen carriage is connected to the slider of a self-balancing Wheatstone's bridge, the arms of which are given suitable values in successive positions of the switch CH2 to produce the same result as regards the travel of the pen as in the other arrangement.