Switching mechanism for circuit breaker

Abstract

A switching mechanism for a circuit breaker includes a frame; a latch rotatably supported on the frame; a holder rotatably supported on the frame and having a movable contact; a handle lever rockably supported on the frame by lever shafts; a toggle link formed of first and second links rotationally connected by a toggle shaft; and a switching spring. A free end of the first link is rotatably connected to the latch, and a free end of the second link is rotatably connected to the holder. The first and second links generally overlap each other to reduce the movement range of the toggle link to miniaturize a switching mechanism. The switching spring is situated between the toggle shaft and the handle lever at a side opposite to a switching handle with respect to the lever shaft. When the handle lever is moved, operational force of the switching spring relative to the toggle link is reversed to rotate the holder with the movable contact, and when the latch is disengaged, the operational force of the switching spring relative to the toggle link is reversed to rapidly rotate the holder to thereby trip the movable contact.