GB1391113A - Electric circuit-breakers - Google Patents

Abstract

1391113 Automatic circuit-breakers STOPCIRCUIT 9 May 1972 [18 May 1971] 21495/72 Heading H1N A circuit-breaker having an operating pushbutton 29 and a release push-button 31, bimetallic tripping means and a pivoted movable contact carrier 8, is characterized by a cam latch 16, pivoted at 4 on carrier 8, having a heel 17 engageable by a notch 33 on button 29 and a heel 18 engageable by a blade 22 pivoted on a pin 5 on carrier 8, the blade 22 normally retaining rotation of cam 16, carrier 8 also supporting a pivotable bent lever 25 movable upon overload by bimetallic strip 27 to pivot blade 22 and release cam 16, thereby releasing the carrier 8, and a second latch 39 engageable in a second notch 34 of button 29 and releasable either by button 31 or by the tripping and opening movement of the carrier 8 to release-button 29. Excessive over-current causes ferro-magnetic blade 22 to be attracted by electromagnetic coil 44 to release cam 16. Screw 30 allows for adjustment of bimetal 27 and an ambient temperature compensating bimetal 48, Figs. 8-10 (not shown), is provided. The main movable contact of the circuit-breaker may be a bridging contact, both opening and closing circuits upon actuation, Figs. 11, 12 (not shown). A plurality of circuit-breakers may be linked for conjoint operation, Figs. 13, 14 (not shown). The bearings of the pivot pin 3 of carrier 8 are elongated apertures 38, such that upon closing the member, carrier 8 pivots first about pin 3 and then pivots about its point of engagement with fixed contact 11.