GB558416A - Selector switch - Google Patents

Abstract

558,416. Automatic exchange switches. STANDARD TELEPHONES & CABLES, Ltd. Dec. 24, 1942, No. 18321. Convention date, Feb. 2. [Class 40 (iv)] A power-driven switch comprises a flat terminal bank over which travels a carriage carrying contact-members with precious metal engaging portions for making contact between terminals and feeder bars when the switch is stationary but not when it is in motion. General arrangement.-Three selectors are provided with a common dust-tight casing having white enamelled walls and a transparent cover to facilitate inspection. The base of the casing is formed by the terminal bank and the inside is thus free from wiring. Terminal banks,-wipers, wiper-positions indicating. Each outlet has A, B, C and T terminals, Fig. 8, the last-mentioned being engaged by wipers 29 steadied by a member 28 and the others having precious metal edges and co-operating with U-shaped springs 19, Fig. 9, having one end split and provided with precious metal contact portions 21 for engagement with the terminals and the other end provided with a similar contact 22 for engagement with the precious metal edge of a feeder bar 32. A supplementary contact with the feeder bar is made by a springs 20. Fig. 9 shows the position of the springs when the switch is in motion. When it stops, magnet 86 is is released and a member 25 forces the arms of the U-shaped springs apart to connect the selected terminals to the corresponding feeder bars. In a modification, Figs. 14 to 18 (not shown), the member 25 is controlled by a bar running the length of the switch and rocked by the clutch magnet. The wipers travel over different rows of terminals during the go and return movements, the wiper-carrying part being moved in relation to the rest of the wiper carriage by a rack and pinion arrangement, Fig. 13, controlled by a shaft 89 which is moved through 90 degrees when the carriage reaches the end of its travel in either direction and begins to reverse. Strips are provided graduated in wiper positions along both edges, one or other of two pointers carried by a common arm being on view according to the direction of travel. Driving arrangements.-A double-worm is formed on the main shaft 58 and co-operates with a projection on the wiper carriage to make it move to and fro along a guide bar 11. The shaft 58 has keyed to it a ribbed cone 62 which is forced against a driving disc of leather &c. by a spring 64 when the clutch-magnet is energized, the forked end 71 of the armature of the latter, which normally holds the driving cone against a rubber stop 68, being then moved clear so that it is not in engagement with the cone when the switch is being driven. Home contact springs.-These are carried in a separate moulding which is forced into the main frame moulding and are operated by rotation of a shaft 12. This may take place at any position of the wiper carriage according to the position of an adjustable part 114.