GB1458022A - Electric circuit breakers printer control system - Google Patents

Abstract

1458022 Automatic circuit breakers FEDERAL PACIFIC ELECTRIC CO 12 Dec 1973 [22 Dec 1972] 57617/73 Heading H1N The movable contact arm 18 of a circuit breaker, Fig. 1, pivots on a transverse helical spring 20 to provide an overtravel feature and is pivotally connected at 36b between two side portions of the operating arm of a bell crank 36 having a single-sided latch arm portion 36a which is put into latching engagement with an armature 26 of thermal/electromagnetic trip means 22-28 to allow the contact arm 18 to be moved to the contact closed position by means of a lever 40 of a pivoted manual operator 38 which acts to erect and overset a toggle linkage 36, 50, 48 against the force of a spring 44. The two side portions of the operating arm of the bell crank 36 are unitarily bridged by a member 36b and are pivotally connected at 54 to side portions of the interconnecting link 50 which is similarly bridged by a member 50c and is pivotally coupled at 52 to a bridged member 48 (see Fig. 4) which is held in assembly to the fixed pivot 42 of the manual operator 38. The toggle linkage arrangement is such that adjacent parts have an interference-free fit within one another under all conditions of operation and the latch arm 26a can lie alongside the contact arm 18 when the circuit breaker is tripped and the handle held "ON", Fig. 2, thus providing for an unusually large opening travel of the contact arm 18 to a backstop 10b. An iron arc runner 56 and iron splitter plates 58 exercise arc control with hot gases being emitted through a wire mesh screen 60 dispersed across a vent 62. Arcuate beads 38c on the manual operator 38 are received in grooves in the walls of housing parts 10, 11 and act as hot gas barriers.