GB1149358A - Circuit breaker - Google Patents

Abstract

1,149,358. Automatic circuit breakers. TEXAS INSTRUMENTS Inc. 13 Oct., 1966 [24 Oct., 1965], No. 45854/66. Heading H1N. In a thermally responsive automatic circuitbreaker actuated by a push-button 44, Fig. 1, the contacts 148, 172 are retained closed by a thermally responsive latch 112, 124 and the push-button is latched in the contacts closed position by a ball catch 78, 86 when the contacts are closed. The movable contact 148 bridges a pair of fixed contacts 170, 172, Fig. 2, and is mounted on a U-shaped spring steel clip 158 attached to a bell crank 104 on the lower end of ball catch member 86 slidable within a bore 76 of the push-button 44. Spring 117 coupled between the bell crank 104 and a fixed plate 119 operates both to open the contacts when released by the thermally responsive latch 112, 124 and also to push the ball-catch member 86 upwardly in the push-button 44 to lock the push-button against return spring 70 by engagement of balls 80, 82 against shoulders 92 in the threaded mounting sleeve 24. The thermally responsive bimetal element 180, Fig. 17 is of inverted U-shape and mounted at its ends on a channel shaped bracket 190 carrying an adjustment screw 196 engaged between opposite arms of the bracket. The element 182 carries current between the fixed contact 172 and terminal 12, one of its arms being on an insulated mounting for connection to a terminal strip 178. Release of the catch 112, 124 is obtained through a sliding plate 204 engaged by the element 180. Ambient temperature compensation is provided by a second bimetallic element 122, Fig. 9, also of inverted U-shape and pivoted at the lower end of the arms in slots 136 of the casing. Sliding plate 204 engages the element 122 which is coupled to the thermal catch element 124 at the lower pivoted end and yieldingly held by a spring 126 engaging the casing 14. Since the bimetal elements 122, 180 act in opposition on the latch 112 with changes in ambient temperature the latch is unaffected by these changes. The casing is made in halves in which the thermal elements, fixed contacts and terminals are initially mounted before assembly. The push button 44 may be inserted as a separate assembly including the moving contact 148 and thermal operating slide plate 204 for engagement in opposite grooves 108, 110 of the assembled halves of the casing.