| 摘要 |
PROBLEM TO BE SOLVED: To prevent the instability of a pull-out operation characteristic of a circuit breaker due to the adverse effect of a component and the assembling accuracy of a contact switching mechanism. SOLUTION: With respect to the contact switching mechanism formed of an assembling frame fitted with a switching lever biased by a main spring, a toggle link mechanism, a latch 17 with a claw linked to the toggle link mechanism and a swaying latch rest 19, in which the latch rest releases the lock of the latch in response to the movement of an overcurrent pull-out device and opens a main circuit contact by the toggle link mechanism and a switching lever, positioning stoppers 17a-2 for regulating a locking engagement position with the latch rest are fitted at both ends of a claw 17a of the latch 17, and are made in contact with the front face of the latch rest, with the latch claw in a state of being engaged with the latch rest. By this, the overlapping width S of an engagement protrusion of the latch claw with the latch rest becomes always constant, thus enabling the stabilization of the pull-out operation characteristic. COPYRIGHT: (C)2004,JPO
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