Patent GB-529048-A (GB)
Title: Improvements in automatic switches for use in telephone or like systems
IPC: H01H67/12
Filed: 1939-05-09
Abstract: 529,048. Electric selectors. MERCER, R. (Associated Electric Laboratories, Inc.). May 9, 1939, No. 13881. [A Specification was laid open to inspection under Sect. 91 of the Acts, Dec. 21, 1939.] [Class 40 (iv)] A selector mechanism which co-operates with a bare wire multiple comprises a number of wiper units arranged side by side, one of which is selected for movement in two directions, the three selections being effected by means of three operating bars which are moved longitudinally under escapement control. As shown, five wiper units such as 40, 41 are provided, each having pairs of wipers which are connected up alternatively. Each unit comprises a carriage 42 mounted on a longitudinal guide bar and carrying a movable slide 43 on which the wipers are mounted. The operating bars 59, 60, 61, which are arranged in superposed relation, are moved to the left in succession into one of ten operative positions. The hundreds bar 59 carries five spaced lugs 64 for co-operation in turn with latches 66 on the carriages 42, a selected carriage being coupled to a bar 70 connected to the tens bar 60 by operation of the appropriate latch, which is retained by an individual member 75'on a fixed bar 76 when the tens bar moves off-normal. Each latch is operated in two consecutive positions of the hundreds bar 59, and a cam 243 on the end of the latter controls contact springs 237 to connect up the odd and even wipers alternately. After the movement of the selected carriage by the tens bar 60, a flange 106 on the slide 43 stands opposite one of ten grooves in a downwardlyextending transverse member 105, so that the slide may be moved forward into the multiple. This movement is effected by a spring-controlled bell-crank 80 coupled to the slide by a pin-andslot connection as a stop 98 on the units bar 61 is progressively withdrawn. Each of the operating bars is biassed to the left by a spring 130 which acts through a lever 123 and carries a rack 119 in engagement with a pinion 113 integral with a ratchet-wheel 132 under the control of an escapement 135. By means of sequence cams 157 &c. the three escapements are brought successively under the influence of a striking flange 153 on the armature 146 of a magnet M1 so as to release the ratchet wheel and allow one step of the operating bar for each impulse received by the magnet M1. The three sequence cams 157, which are integral with a ratchet-wheel 155 driven by a pawl 185 on the armature of a magnet M2, each have four teeth in staggered relationship and cause three bellcranks 160-162 to be rocked in succession as the cams rotate to bring corresponding tappets 164 between the flange 153 and the escapements. A normal position of the ratchet-wheel 155 is followed by three operative positions and one inoperative position before a fresh normal position is reached. Further cams close contact springs 260, 270 in the normal and,fourth offnormal positions. During the setting of the selector, the magnet M2 receives a .preliminary impulse, a further impulse after each train of impulses received by the magnet M1, and a final impulse when the selector is to be restored. Restoration is effected by a motor M3 having two windings disposed at right angles which are energized alternately over contacts 204, 205 controlled by a cam 203 on the rotor. The latter drives two discs 210, 219 which carry studs acting in turn on fingers on the levers 123 to restore the operating bars to normal. The motor is disconnected after one revolution of the discs by the opening of contact springs 223. Each of the operating bars controls a lever 225 which exhibits through an aperture 33 in the front plate 29 an indication of the position of the corresponding bar. The hundreds and tens bars control off-normal springs 245 and the magnets M1, M2 control'springs 233, 280. A test jack 254 is available through an aperture 35. The selector units are mounted one above the other on both sides of the multiple 24 with vertical staggering. The base plate 28 of each unit is supported on ledges 26 and is secured to the side frames 22 by screws 20 engaging in slots 31 to allow adjustment in a longitudinal direction. A pair of screws 32 permit adjustment to and from the multiple. Specification 529,049 is referred to.