GB429543A - Improvements in or relating to electric circuit interrupters - Google Patents

Abstract

429,543. Automatic circuit-breakers. WESTINGHOUSE ELECTRIC & MANUFACTURING CO., East Pittsburg, U.S.A.- (Assignees of Lindstrom, T.; 443, Morris Street, Edgewood, Pennsylvania, U.S.A.) April 24, 1934, No. 12352. Convention date, April 24, 1933. [Class 38 (v)] Operating-mechanism for a circuit-breaker comprises an operating-member 23, a pair of toggle links 83, 84, spring means 99 operatively connecting the knee of the toggle with the operating member, and latch means 87 engaging the pivot pin 93 of the toggle link 83 to prevent closure of the switch during the first part of the closing movement of the member 23, the latch being released by a projection 127 on the operating member towards the end of the closing movement, whereupon the spring 99 closes the switch with a snap action. The invention is shown as applied to a three-pole switch with terminal contacts 3, 5, arc extinguishers 13 of the magnetic plate type, fixed contact assemblages 15, and movable contact assemblages 11 connected together by a bar 43, the several poles being separated by partitions 17. Each of the movable contact assemblages 11 comprises a central contact member 49, Fig. 13, having main contacts 51 and arcing contacts 50, and two outer main contact members 52, the whole being carried by a clamp 45 secured to the bar 43. The outer contact members 52 are pivoted to the clamp at 53 and biassed towards the corresponding fixed contacts by springs 55. The central member 49 is biassed towards the fixed contacts by a spring 66 surrounding an L-shaped guide 68, which engages the contact member through the agency of a pin 69 and slot 63, this arrangement serving to concentrate the force of the spring 66 near the arcing contact 50. The clamp member 45 of the central switch assemblage 11 has a bifurcated section 76 pivoted to the toggle link 83 at 78. The other toggle link 84 is held by one end of a bell-crank carrier lever 105 pivoted at 109, the other arm of the lever 105 being normally held by a latching lever 111 pivoted at 115 and releasably restrained by a catch 117 which is adapted to be tripped in response to a predetermined electrical condition. The tripping device may comprise thermally responsive and magnetically responsive elements connected in each pole of the circuit-breaker and a common trip bar actuable by any one of the elements. When the tripping device operates and releases the latching lever 111, the parts assume the position shown in Fig. 5 ; in this position a latch 89 engages wedge-shaped projections on the toggle lever 84 and locks the mechanism in the tripped position. To release the latch 89 and reset the latching lever 111 the handle 25 is moved to the right to the full " off " position, when a roller 137 on the member 23 engages the carrier lever 105. In closing the circuit-breaker, the handle 25 is moved to the left, the toggle link 83 being held by the latch 87 until the spring 99 has been sufficiently strained, whereupon the projection 127 releases the latch. Shortly afterwards, another projection 141 on the operating member 23 engages a projection 140 on the movable switch member and gives the latter a positive movement towards the closed position, in the event of the movable member sticking.