GB1222428A - Automatic circuit interrupter - Google Patents

Abstract

1,222,428. Automatic circuit-breakers. MITSUBISHI DENKI K.K. 18 March, 1968 [16 March, 1967], No. 12899/68. Heading HlN. The moving contact arm 34 of a small circuitbreaker is coupled to a switching handle 50 by toggle links 42, 46 which are restrained in the substantially aligned position shown in Fig. 2 by a link 92 coupled by a pin 88 to a latch 84 which is pivoted at 86 on a stationary supporting plate 28. A spring 94 tends to turn contact arm 34 clockwise about its pivot 32 while springs 56 and 90 tend respectively to turn handle 50 and latch 84 in the clockwise direction, spring 94 being effectively stronger than spring 50 which in turn is stronger than spring 90. Overcurrent in coil 64 pivots armature 70 about pin 72 and an upstanding portion engages a tripping plate 82 mounted on a bell-crank member 76 to pivot the latter and lift a pin 78 thereon clear of the nose of latch 84 allowing spring 94 to collapse toggle 42, 46 with its apex away from latch 84 and to open contacts 36, 24 (as in Fig. 3, not shown). The springs 56 and 90 then co-operate to straighten the toggle 42, 46 and return latch 84 to be retained by pin 78, the armature 70 having been restored by a spring 74 upon the circuit interruption. Movement of handle 50 in an anti-clockwise direction from this tripped condition (Fig. 4, not shown) exerts a thrust on the toggle 42, 46, which is maintained by link 92 in a substantially aligned condition, and recloses contacts 36, 24 as in Fig. 2. The link 92 may be pivotally connected to the toggle link 46 instead of to the junction pin 48 (Fig. 6, not shown), or the latch 84 may be arranged to turn in the reverse direction by pivoting its central portion on pin 86 and coupling link 92 to its lower extremity (Fig. 7, not shown).