Patent GB-392964-A (GB)
Title: Improvements in or relating to switches such as are used in automatic telephone systems
IPC: H01H67/12
Filed: 1931-11-27
Abstract: 392,964. Automatic exchange switches. STANDARD TELEPHONES & CABLES, Ltd., SMITH, C. P.,. and NEWTON, G., Connaught House, Aldwych, London. Nov. 27, 1931, No..32921. [Class 40 (iv).] A unitary switch structure of cross-bar type comprises means for selecting an idle outlet and for connecting any one of a plurality of inlets to the selected outlet. The structure is particularly suitable for use as a group of conversational switches combined with a common marker. Construction, Figs. 1-3. Each outlet is multipled to ten sets of three wires a, b, c, Fig. 1, bent so as to project through bars 13 on either side of the structure. Each outlet also has two test wires 11, 12, terminating at one end in commutator segments 28 adjacent to continuous feed-strips 29. Each inlet is wired to a set of angle-iron contact bars 1 pivoted obliquely to the armature 20 of a magnet 21 and to a counterweight 37, Fig. 2. Test wipers 4, 4<1>, Fig. 3, bridging the commutators 28 and strips 29 are mounted on a bar member 27 adapted to slide on a rod 35 which is mounted on pivoted levers 31 in such a way that the energization of magnet 33 causes a half-nut on member 25 to engage a driven shaft 24 to raise the wipers. On the de-energization of magnet 33 when an idle outlet has been selected, the bar 27 is moved toward the bank by a spring 30 and by means of projections 14 engaging a pair of bars 13 moves the terminals of the selected outlet into an off-normal position. The magnet 21 corresponding to one of the inlets is then energized to move the bars 1 obliquely to the right (Fig. 1) causing them to make a rubbing contact with one of the displaced sets of contacts of the selected outlet. The shaft 24 may be driven by an individual motor 5 or from a common drive through gearing. Off-normal contacts 38 controlled by bar 27 and contact-springs 39 operated by magnet 21 are provided. Circuit arrangements, Fig. 4. This Figure shows one of a group of second group selectors associated in multiple with a single control circuit comprising wipers 4, 4<1>, and a separate group-marking single-motion switch PM. When the selector is seized, relays A, B, operate and start the motor 5. Impulses are repeated by relay A to magnet PM and as soon as wiper pm 2 moves off-normal, magnet TM (33, Fig. 3) is energized to raise wipers 4, 4<1>. When the first contact of the selected group is reached, relay M operates, releasing magnet TM and energizing relay E which connects test relay P to wiper 4<1>. Relay M now releases and magnet TM is again energized until an idle outlet in the selected group is reached when relay P operates and energizes H which completes a circuit for magnet CM (21, Fig. 2) to the conversational switch. The release of relays A, B, causes switch PM to restore to normal and energizes relay N which reverses the connections to the motor 5 and energizes magnet TM. The wipers 4, 4<1> are thus driven downwards until the off-normal contacts on (38, Fig. 3) are restored and relay N released. If there is no idle outlet in a selected group, relay M energizes over wiper 4 and .the last contact of the group energizing relay G which connects up busy tone and operates relay N to restore wipers 4, 41 to normal.