Patent ID: 6229414
Filing Date: 2001-05-08
Classification: H01H

Abstract:
A make-and-break mechanism for use in a circuit breaker comprising:an operation handle rotatably supported on a frame composed of a cover plate and a back plate through a handle shaft;a make-and-break lever rotatably supported on a case through a make-and-break shaft and energized in one direction by a main spring; a mechanism member for transmitting the operation of said operation handle to said make-and-break. lever;a latch having one end connected to said operation handle through said handle shaft;a U-shaped pin disposed so as to bridge over said latch and said mechanism member; anda latch receiver rotatably supported on said frame and, when said make-and-break mechanism is held in the on state, capable of securing the other end of said latch, wherein, in case where the secured condition of said latch by said latch receiver is removed due to the operation of an overcurrent detect portion of said make-and-break mechanism, said make-and-break lever is driven to an off position due to the stored energy of said main spring to thereby break the contact of a movable contact member, and, during this operation, in case where the secured condition of said latch is removed, an alarm output plate, which is disposed in said make-and-break mechanism so as to be slidable along said cover plate, is driven or moved in the upward direction from a wait position to operate an alarm contact;wherein, in said cover plate, there are provided a pair of right and left engaging projections and, in said alarm output plate, there are formed inverted-L-shaped guide holes which can be slidably fitted with said engaging projections; between a pin for connecting said operation handle to said mechanism member and said alarm output plate, there is provided a handle spring composed of a tension spring; in the on/off state of said make-and-break mechanism, the shoulder portions of said guide holes are engaged with said engaging projections to thereby hold said alarm output plate at a wait position; and, in the on state of said make-and-break mechanism, in case where the secured condition of said latch is removed, said alarm output plate is pushed by said U-shaped pin operatable in linking with said latch to thereby remove said engagement, whereby said alarm output plate is moved in the upward direction along said guide holes due to the spring force of said handle spring and, at the same time, said operation handle is rotated to a trip display position.