Patent GB-564770-A (GB)
Title: Improvements in or relating to telephone systems and automatic switches for use therein
IPC: H01H67/06
Filed: 1943-04-07
Abstract: 564,770. Automatic exchange systems; switches. AUTOMATIC TELEPHONE & ELECTRIC CO., Ltd. April 7, 1943, No. 5581. Convention date, April 13, 1942. [Class 40 (iv)] [Also in Group XXIV] A rotary power-driven switch moves quickly over groups of terminals during its primary movement and slowly in the same or in the opposite direction over the terminals of a group during its secondary movement with the aid of a change-speed gear. The switch is controlled by a number sender of the kind disclosed in U.S.A. Specification 2,222,131, which interrupts the line circuit for periods proportionate to the values of the digits, but according to the Specification as open to inspection under Section 91 may be controlled by an associated minor switch responsive to ordinary impulses by marking. Construction of switch.-As shown in Figs. 1 and 2, the wiper carriage 106 is secured to a ring gear 126 meshing with pinions 124, 125 in a cage formed by a pair of plates 108, 109, the lower of which is secured to a flexible clutch plate 111. These pinions mesh with a pinion 121 carried by a shaft 105 which can be clutched to a constantly running shaft 140 by a magnet 151 or stopped by a magnet 152. With magnet 131 de-energized, the clutch plate 111 engages. the edge of the gear 126 and the wiper-carriage, cage and driving pinion 121 rotate as a whole when clutch magnet 151 is operated. When, however, magnet 131 is operated, the cage is held stationary by engagement of the clutch plate 111 with a fixed ring 135 and the wiper carriage thus moves at a slower speed in the opposite direction to the driving pinion. In a modification, Fig. 3, the cage carries intermediate pinions 30 i, 302 to cause the secondary motion to take place in the same direction as the first. Specification 555,097 is referred to. Circuit arrangements.-When the switch shown in Fig. 10 is seized, line and release relays 1310, 1320 pull up and also STOP relay 1365 and STOP magnet 1357 in series. The subscriber's dial interrupts the line circuit for a period corresponding to the digit selected and during this period STOP magnet and relay 1357, 1365 are de-energized and GO magnet and relay 1356, 1360 and relay 1330 are operated. The switch is thus rotated at high speed for a corresponding period after which 1310 pulls up again and the switch is stopped. Relay 1330 is restored and energizes 1350 over offnormal springs 1339 to cause the operation of gear-change magnet 1358. In response to the next digit, therefore, the switch rotates at its lower speed. Operation of relay 1330 this time energizes 1340 partially, full energization taking place when 1330 falls at the end of the digit. Ground is thus connected to 1380 which pulls up in series with 1370 if the line is idle and connects the ringing relay 1390 to interrupter 1317, 1370 being unable to operate in this circuit. If the line is busy, however, 1370 pulls up alone to ground on wire 1313 and sends back busy tone. When the wanted party replies, back-bridge relay 1375 energizes 1370 which disconnects the ringing relay. When the calling party hangs up, the relapse of 1310, 1320 completes a circuit for the GO magnet and relay over off-normal springs and the switch is restored at high speed, the relapse of 1350 releasing the change-gear magnet. The Specification as open to inspection under Section 91 comprises also a circuit, Figs. 10, 11 (cancelled), for the control of the switch by incoming impulses of ordinary kind. The first digit is repeated to the minor switch 1120, which is arranged to ground a corresponding number of terminals. The GO magnet of the switch is thus operated in series with the GO relay 1060 over wiper 1115 and the switch proceeds at high speed to the first ungrounded terminal engaged by this wiper, whereupon the GO magnet and relay fall, the STOP magnet and relay pull up and the minor switch is released. Relay 1030 is energized during the digit and on falling back at the end of the digit prepares a circuit for 1050 which is completed when the GO relay also has fallen back. 1050 locks up, energizes the change-gear magnet 1058 and gives control to wiper 1114 in place of wiper 1115. The second digit operates the minor switch in the same way and the switch moves to the appropriate terminal in the wanted group at a slow speed. Busy test, ringing and release take place substantially as in the other arrangement. This subject-matter does not appear in the Specification as accepted.