Patent GB-191313748-A (GB)
Title: Improvements in Selectors for Automatic or Semi-automatic Telephone Systems.
Filed: 1913-06-13
Granted: 1914-06-11
Abstract: 13,748. Siemens & Halske Akt.-Ges. June 22, 1912, [Convention date]. Automatic and semi - automatic exchange systems.-Relates to relay sets of the kind in which a chain of relays is progressively energized by a series of impulses to effect or control a selective operation, and comprises improvements on the arrangement described in Specification 18,430/12, in which each impulse energizes only one relay instead of a pair. According to the present invention, only a single impulse-producing device (key or interrupter) is necessary, in place of the two previously used, and the control may be effected over a single lead. In one arrangement, the number of selective positions is twice the number of relays in the chain. The invention is described in its application to arrangements in which an impulse circuit is opened when the impulses have built up the relay chain to a point corresponding to a particular key of a keyboard, such as 23, Fig. 1. The depression of the key 23 prepares the circuit of the cut-off relay P, which is energized by the relay IV in response to the fourth impulse in the circuit t, U. The impulses repeated by the relay U in the circuit p, u<1> are directed by a relay F alternately to leads L', L<2>, to which the relays I, II, III, &c. are alternately connected. The relav F is energized at the termination of the first or other odd-numbered impulse by a circuit u<2>, F', 3, 4, II and is de-energized at the termination of the second or other even-numbered impulse by the opening of a locking-circuit at u<3>, the other circuit having been opened at 4 bv the energization of the relay II. The relays I, II, III, &c. are eventually unlocked by opening a switch T. In another arrangement, in which the relays are all connected to a single lead instead of to the two leads L<1>, L<2>, each relay, when energized, unlocks the preceding relay and prepares the circuit of the next relay, which is however temporarily short-circuited to prevent it from being energized by the same impulse. In the arrangement shown in Fig. 3, there are two keys 25, 26, &c. associated with each of the relays I, II, III, &c., these relays being energized by the first, third, fifth, &c. impulses from the interrupter S. The cut-off relay P is energized after an even or odd number of impulses accordingly as the depressed key was the first or second of the pair associated with a particular relay. The relay H controls relays U, J in such a manner that the relay J is energized by the first, third, fifth, &c. impulses and de-energized by the second, fourth, sixth, &c., while the relay U is energized at the termination of the first, third, fifth, &c. impulses and de-energized at the termination of the second, fourth, sixth, &c. For instance, the first impulse energizes the relay J, which closes a locking-circuit through the relay U and contact i, but the relay U is for the moment shortcircuited at the contact h<1>, and only energizes . at the termination of the impulse. The second impulse closes a circuit through the relay U and both differential windings of the relay J, which therefore de-energizes, and at the termination of the impulse the relay U is opencircuited and also de-energized. When the relay U is energized at the termination of the first impulse, it closes a circuit through the relay I, which locks itself up, and when the relay U de-energizes at the termination of the second impulse, it closes a circuit through the relays F and II. The relay F, which is of comparatively high resistance, is energized, but the relay II does not respond. When the relay U is energized again at the termination of the third impulse, the relay F remains energized by a locking-circuit through its lower winding, and a circuit is closed over contacts f<2>, 3, 4, for the relay II, which locks itself up. It will be seen that the relay F is de-energized again along with the relay U at the termination of the fourth impulse, and thereafter is reenergized at the termination of the sixth impulse, and de-energized again at the termination of the eighth, and so on, with the result that the contact u<5> is connected alternately to the leads L<1>, L<2>; so that the relays I, II, III, &c. are energized successively when the contact u<5> is closed at the termination of the first, third, fifth, &c. impulses. The keys 25, 26, &c. are wired alternately to leads L<4>, L<5>, of which L<4> is connected directly to a contact h<2> while L<5> is connected thereto through a contact u<4>. Taking, for instance, the keys 31, 32 associated with the relay IV, which is energized at the termination of the seventh impulse, if the key 31 has been depressed, the cut-off relay P would be energized by the succeeding eighth impulse, but if the key 32 had been depressed, the circuit of the relay P would be open during the eighth impulse at the contact u<4>, and the relay P would only be energized at the ninth impulse, the contact u<4> having been closed at the termination of the eighth impulse by the de-energization of the relay U.