Patent GB-154698-A (GB)
Title: Improvements in or relating to automatic switching mechanism for use more particularly in telephone or like systems
IPC: H01H63/22
Filed: 1919-09-02
Abstract: 154,698. Automatic Telephone Manufacturing Co., (Automatic Electric Co.). Sept. 2, 1919. Automatic exchange systems and selectors.-An electric selector, particularly for use in automatic exchange telephone systems, is operated step by step by the alternate energization of two electromagnets 6, Fig. 3, the pole-pieces 10, 12 acting on a specially shaped armature 18 so as to rotate a shaft 15 half a revolution at a time in the direction of the arrow. Each revolution of the shaft 15 moves the wipers from one set of terminals to the next by means of worm gear 2, 3, Fig. 1. The wiper shaft is rotated against a spring, which restores it when the worm 3 is disengaged from the gear 2 by a release magnet 5. A two-co-ordinate selector operated by similar mechanism is shown in Figs. 4, 5, and 6, the same prime mover effecting both vertical and rotary movements of the wipers. For this purpose a magnet 37 is first energized, which slides a pinion 30 into engagement with a rack 29 and releases a double dog 31 from a detent, allowing it to engage ratchet teeth on the rack 29 and on a disk 41 fast to a gear 24. Rotation of the worm 21 by the magnets 6 now raises the shaft 26 through gears 25, 40, 39, 30, 29, and the shaft lifts with it a sleeve 32 which carries the wipers. The magnet 37 is then deenergized, to disconnect the pinion 30, and a magnet 23 is energized to engage the worm 21 with the gear 24. Further rotation of the worm 21 therefore operates the gear 24, which rotates the wiper sleeve 32 through a spline connexion 33. The selector is released by a magnet which returns the dog 31 behind its normal detent. It is stated that there may be more than two of the operating-magnets 6, and that, on the other hand, a single magnet will suffice if used in conjunction with a biassing-device. Small automatic exchange, Fig. 7. This Figure shows the circuits of a small exchange in which each subscriber has a 25-point selector as shown in Fig. 1. To call the 23rd line, the subscriber sends in ten, ten, and three impulses. When the calling subscriber lifts his receiver, the line relay 42 and a slow-release relay 45 are energized in the ordinary way. The line interruptions are repeated by the relay 42 as impulses in the circuits of the operating-magnets 51, 68, magnet 51 being energized in series with a slow-release relay 50 at the beginning of each interruption and magnet 68 (through a circuit prepared by relay 50) at the end of each interruption. The ten impulses bring the wipers to a blind set of terminals, of which the second line terminal is grounded as shown at 102, so that when the relay 50 relapses at the termination of the series of impulses a relay 81 is energized to prevent the energization of a relay 63. These operations are repeated for the second set of ten impulses, the twentieth set of terminals being blind like the tenth, and the third set of impulses brings the wipers to the terminals of the wanted line. When the final series of impulses has terminated, relay 50 relapses, and is followed by a relay 71 which it controls, and in the interval between the de-energization of these two relays the test wiper 60 is connected to relay 77. If the wanted line is busy, relay 77 is energized, locks itself and relay 71, and connects a busy signal to the calling line. If, however, the wanted line is idle, the relapse of relay 71 completes a circuit 62, 90, 79, 91 for energizing relay 63, which grounds the test wiper and connects the ringing- apparatus R to the selected line. When the called subscriber answers, relay 77 is energized by the direct current which then flows in the ringing- circuit, locks itself, disconnects the ringer, and completes the talking-connexion, the called line being fed with current through relay 81. The release magnet 5 is energized as a consequence of the relapse of relays 42, 45 when the calling subscriber disconnects himself. Signalling the sending of an accidental switchhook impulse. The set of terminals to which the switch is moved by the first impulse is connected to the busy signal device, so that the calling subscriber gets a signal if a single impulse is sent in. Larger exchange with group selectors D, Fig. 8, and connectors H, Fig. 9, constructed as in Figs. 4, 5, and 6. A preliminary selector C, operating in known manner, connects the calling subscriber to an idle group selector D, energizing the line relay 108 and slow-release relay 111 as usual, and relay 111 energizes the preparatory magnet 37. During the first set of line-interruptions, the operating-magnets 183, 182 are respectively energized at the commencement and termination of each impulse, and raise the selector to the wanted level, and the relay 119, which is energized while the impulses are passing, then relapses and completes the circuit of a relay 124, which de-energizes the preparatory magnet 37, energizes the transfer magnet 23, and sends an impulse through a relay 132. The magnets 183, 182 are energized in turn by the response and relapse of relay 132, and move the wipers to the first set of terminals in the selected level. If these terminals are busy, the relay 132 is energized again in a self-interrupting circuit through the test wiper, and the repeated energization of magnets 183, 182 advances the wipers until idle terminals are found. A high resistance relay 138 is now energized in series with relay 132 (being no longer short-circuited through the test wiper) and switches the line circuit to the connector H, Fig. 9, energizing a line relay 143 and a slow-release relay 144 which grounds the incoming test circuit to keep the relay 138 energized. The preparatory magnet 37<1> is also energized by relay 144. In response to the next set of line-interruptions, the operating-magnets 184, 185 are respectively energized at the commencement and termination of each impulse and raise the wipers to the wanted level, and the relay 157, which is energized while the impulses are passing, then relapses and completes the circuit of a relay 160, which de-energizes the preparatory magnet 37<1> and energizes the transfer magnet 23<1>. In response to the final set of impulses, the magnets 184, 185 are alternately energized to rotate the wipers to the wanted terminals, and a relay 164, which is energized during the passage of the impulses, then relapses. Busy test. If the wanted line is busy, a relay 167 is energized over the test wiper in the interval before the relapse of relay 164, and locks itself and completes the circuit of a busy signal through relay 178. Supply of ringing current. If, however, the wanted line is idle, the de-energization of relay 164 completes the circuit of relay 168 over the test wiper 166, and relay 168 locks itself up and connects the ringing generator to line; the supply of ringing-current continues until relay 177 is energized by the direct current which flows when the called subscriber answers.