Patent GB-664696-A (GB)
Title: Bare wire bank
IPC: H01H67/12
Filed: 1948-12-17
Abstract: 664,696. Electric selectors. AUTOMATIC ELECTRIC LABORATORIES, Inc. Dec. 17, 1948 [Dec. 18, 1947], No. 32724/48. Class 40 (iv). Telephone system switching apparatus of the X-Y motions type comprises a primary carriage movable linearly in one direction (X) from a normal position, and a secondary carriage supported by the primary carriage and movable relative thereto from a normal position in a second direction (Y), the secondary carriage supporting contact elements co-operating with bare wire contact banks. Each carriage has a release mechanism which upon operation permits the associated carriage to be restored to normal and means are provided selectively controllable to operate both the release mechanisms together or to operate only the release mechanism for the secondary carriage. Carriage construction and operation, Figs. 1A, 1B, 2A, 2B. A base-plate 10 is detachably positioned relative to the four-section contactbank 200 by frame members 211a, 211b, 212, 213, and carries a guide bar 95, Fig. 1B, on which the primary carriage 16 slides. The carriage is advanced step-bystep from its normal position shown through a ratchet 23 co-operating with the driving pawl 19 actuated through the spring-biased armature 17 of primary magnet 11, and a locking pawl 24, Fig. 2. The carriage is biased towards its normal position where it abuts against a stop 30 by a tension spring 136, Fig. 3A, disposed below the base-plate. The secondary carriage 15 slides on lateral guides 16a, 16b, Fig. 1, formed on the carriage 16 and carries on U-shaped brackets 62 the wiper pairs 1-2, 3-4, 5-6, 7-8 which are advanced step-by-step into the contact banks 200 by pulsing a secondary fixed magnet 12, energization of which through its spring-biased armature 85, driving pawl 87 and ratchet 93 moves to the left, Fig. 1, a rack bar 96 slidably mounted on the guide bar 95, the rack bar 96 acting through pinions 102, 103 and racks 106, 107, laterally slidable relative to base-plate 10, to advance the secondary carriage 15, through brackets 108, Fig. 4, engaging flanges 109 thereon. The secondary carriage is advanced from its normal position shown against the action of a biasing spring 114, Fig. 3A, also disposed below the base-plate 10, and urging the rack 96 to the right. When the secondary carriage is moved off-normal the primary carriage is locked against longitudinal movement. This is effected by a lever 113, Fig. 1, pivoted about a fixed point 115 and carrying a latch 117 at its right-hand end for engaging any one of ten holes 117a, Fig. 2, in the primary carriage 16 corresponding to the various longitudinal positions thereof. In the normal position of the secondary carriage the lever 113 is held in its inoperative position shown by a biasing spring 118, but as soon as the rack 96 moves to the left to move the secondary carriage off-normal the left-hand cam end 112 of rack 96 rocks the lever 113 to lock the primary carriage. Two release magnets 13, 14 are provided. Energization of the first release magnet 13 through its armature 122 rocks a release bar 123, Figs. 3A, 3B, to the right against a biasing spring 125; the release bar through bell-cranks 127, 25 releases both the driving and locking pawls from the respective ratchets 93, 23. The secondary carriage is then returned to normal by its biasing spring whereupon the lever 113 is rocked to normal by its biasing spring to unlock the primary carriage which then returns to normal under its biasing spring. Energization of both release magnets 13, 14 simultaneously effects release of the secondary carriage only, the energization of release magnet 14 rocking the release bar 123 angularly to the dotted position, Fig. 3, so that the bell-crank 25 is not affected when the release bar is moved to the right by energization of release magnet 13 as above described. The bell-crank 127 only is then rocked to release the secondary carriage as before. Such partial release is used in trunk-hunting operations. Auxiliary contacts. The primary carriage includes a control wiper, Figs. 5, 6 (not shown), adapted to wipe over ten fixed contacts as the carriage is stepped from its normal position. Two sets of control springs 31, 35, Fig. 1, may be selectively operated in desired positions of the primary carriage by presetting roller pins 38, 39 into the desired two of ten longitudinally spaced holes in an extension 40 of the carriage. Impulsing springs 52 are operated by the primary magnet 11 at each step of the primary carriage which is also provided with off-normal switch springs 53, Fig. 1. Limit.switch springs 99, 991, Fig. 1b, are operated in the terminal positions of the secondary carriage and impulse springs 219 are actuated by the magnet 12 as the secondary carriage is stepped. Further impulsing springs 218 are actuated by the release magnet 13. Bare wire contact bank construction. Each bank section 200 comprises ten individual contact units 201 held in spaced relationship by bolts 215, Fig. 9. Each unit 201, Fig. 8, comprises an insulating strip 221, longitudinally grooved on both sides to take ten superposed pairs of conductor strips 224, 225, held in position by vertically spaced clamps 230 to define a plurality of contact sections accessible to various switching mechanisms, as above described, arranged in a tier. The clamps are eyeletted at 237, 238 to take the spacing bolts 215, and at their upper ends are secured by a terminal block 240.