Patent GB-190614851-A (GB)
Title: Improved Apparatus for the Automatic Distribution of the Operating Service in Telephone Exchanges.
Filed: 1906-06-30
Granted: 1907-03-21
Abstract: 14,851. Kj÷benhavns Telefon - Aktieselskab. June 30, 1905, [date applied for under Patents Act, 1901]. Telephone systems.-Relates to the automatic distribution of calls to the various operators in telephone exchanges for the purpose of equalizing the work performed by them. An automatic switch is set in action when the subscriber makes the call, which connects his line to the first disengaged line of a series of distributing-lines, common to the particular bank of subscribers' switches on which the call is received. The call is thus carried on to some operator who is disengaged, for each operator while actually engaged blocks all the distributing-lines running from her position. Each subscriber's line may be provided with an automatic switch for selecting an idle distributing-line ; or the subscribers' lines on a given bank may control a single main automatic switch which selects an idle automatic switch associated with a distributing-line. This switch then makes connexion between the distributing-line and the calling-subscriber's line. Fig. 1 shows the automatic switch in section. When the subscriber makes the call by closing the line circuit 35, Fig. 8, the line relay 31 closes the circuit of an electro-magnet 6. The pole-piece 6<a> of this electro-magnet lifts its armature 7 and admits compressed air from the pipe 3 by the valve 4 to the cylinder 1. The piston 2 moves towards the right, coiling the retracting spring 14 and carrying the electro-magnet 10 and four contact-springs 15, 23 with it. The spring 15 passes over a series of contact-studs 17, Fig. 8, and the three springs 23 are adapted to make simultaneous contact with contact-studs in the three rows 24, 25, 26 when the electro-magnet 10 is energized and its armature 20 lifted. The spring 15 forms one terminal of the coil 10. As soon as the contact-spring 15 reaches a contact-stud associated with an idle distributing-line, that is to say a line the terminal plug d of which is in its socket so that the spring 33 grounds the wire 37 leading from the contact stud 17, the electromagnet 10 is energized and the armature 20 attracted. The pins 18 are deviated into a pair of inclined slots 21, and the electro-magnet comes to rest with the springs 23 making contact with the studs 24, 25, 26. The line-wires 35 and subscriber's test wire 36 are thus continued on to the distributing-line leading to an operator's position d. When the convetsation is over, the line circuit 35 is broken by the subscriber, and the relay 31 and electro-magnet 6 are de-energized. The valve 4 closes, and the spring 14 returns the electromagnet 10 and the contact-springs 15, 23 to the extreme left-hand or inactive position. To prevent waste of current, a switch 27 automatically breaks the circuit of the electro-magnet 10 as long as the pins 18 are in full engagement with a pair of the inclined slots 21. The motive power may be mechanical or elastic instead of being pneumatic. A friction clutch controlled by a relay may, for example, give motion to a pulley and cord for the purpose of traversing the electro-magnet 10.