Patent GB-256913-A (GB)
IPC: H04L25/42
Filed: 1925-09-30
Abstract: 256,913. Western Union Telegraph Co., (Assignees of Howard, A. H.). Aug. 14, 1925, [Convention date]. Repeating systems using contact-making relays; restoring or modifying imperfect signals.- Relates to synchronous telegraph systems, more particularly of the kind described in Specification 196,879, having means for receiving or retransmitting the signals, and comprising a rotary distributor co-operating with receiving, storing and re-transmitting relays and consists in providing means to ensure that the storing relay is maintained in energized condition throughout the reception and retransmission periods even should the signal cease before the brush of the distributor has passed from the pick-up segments on to the locking segments. In the arrangement, Fig. 1, positive and negative impulses cause a drum relay 1 to energize the dot and dash relay 7, 8 respectively. The rotary distributor RD is provided with an auxiliary locking ring L2 in addition to the receiving and locking ring L1, the storing or locking relays LR1. LR2 being provided with energizing coils 10 connected with ring L1 and with coils 12 connected to ring L2. Assuming that relay 7 is energized when the brush B1 of the distributor engages the pick-up segments P1 of ring L1, a circuit is closed from positive pole of battery 15 through tongue of relay 7, conductor 16, pick-up segments P1, brush B1, coils 10 of relays LR1, LR2, conductor 18. to neutral point O of battery, thereby causing tongue of locking relay LR1 to move over against its right hand contact, as indicated in dotted lines. As soon as tongue of relay LR1 touches its right hand contact, an auxiliary locking circuit is closed from the positive pole of battery 15 through conductor 20. tongue of relay LR1, coils 12 of relays LR1, LR2, conductor 26, pairs of.segments l<5> of auxiliary ring L2, brush B2, solid ring S2, and conductor 27 to neutral point 0 of battery. The brush B2 is positioned so as to move on to segments l<5> before brush B1 has passed off pickup segments P1 so that even though the current should cease before the brush B1 has passed from the pick-up segments P1 on to the locking segments l<1>, the relays LR1, LR2 will remain energized through the auxiliary circuit indicated above. When the brush B1 passes on to the locking segments l<1> a circuit is completed from positive pole of battery 15 through conductor 20, tongue of relay LR1, conductor 21, coils of retransmitting relays SR1, SR2. conductor 23, locking segments l1, brush B1, solid ring S1, conductor 17, coils 10 of relays LR1, LR2 and conductor 18 to neutral point of battery, thus causing the tongue of relay SR1, to be moved against its right hand contact. so as to connect the positive pole of battery 25 with cable C2. In order to ensure the breaking of the circuit of the preceding signal before brush B1 receives the succeeding signal impulse in passing from locking segments l1 on to the next pickup segments, the brush B2 is staggered behind brush B1 so that brush B2 does not pass on to segments l5 before brush B1 has moved off a group of locking segments l1, l2. l3 or l4, for a previous signal. In the system shown in Fig. 1, the duration of the signal impulses repeated into cable C2 is necessarily less than the unit time allotted to a signal impulse since the signal is not transmitted by the relays SR1, SR2 until the brush B1 has moved upon the first segment of one of the connected groups of locking segments. Fig. 2 shows an arrangement similar to that shown in Fig. 1 but in which the repeated signal can have a duration equal to the full unit period allotted to a signal, the relays SRI, SR2 being energized as soon as brush B1 moves on to one of the pick-up segments. Assuming, as before, that the dot relay 7 is energized, a circuit will be completed from positive pole of battery 15 through tongue of relay 7, conductor 16, pick-up segments P1 brush B1, solid ring S1, conductor 17, coils 10 of relays LR1, LR2, conductor 23<1>, coils of relays SR1, SR2, and conductor 18<1> to neutral point O of battery. The energizing of the relay LR1 acts, as before, to close an auxiliary locking circuit, the circuit in this case being from the positive pole of battery 15 through conductor 20, tongue of relay LR1,conductor 22, coils 12 of relays LR1, LR2, conductor 26, locking segments l5 of ring L2, brush B2, solid ring S2, and conductor 27 to neutral point O of battery. As soon as brush B1 passes on to locking segments l1 the coils 10 of relays LR1, LR2 are energized over a circuit from positive pole of battery 15 through conductor 20, tongue of relay LR1, conductor 23<1>, locking segments l1, brush B1, solid ring S1. conductor 17, coils 10 of relays LR1, LR2, conductor 23<1>. coils of relays SRI. SR2 and conductor 18<1> to neutral point O of battery.