Patent ID: 8183485

Claim:
A circuit breaker having an automatic release linkage including a movable conduction unit for selectively conducting a first terminal and a second terminal by contacting the second terminal while being electrically connected to the first terminal, and an open/close linkage including a connection linkage for transmitting an impact force from the movable conduction unit to a trip roller as an operational force, the circuit breaker comprising: an open lever; a first link rotatably fixing the trip roller, rotatably formed about a latch pin and having a size such that the first link does not interfere with the open lever during rotation; a second link rotatably coupled at the first link to facilitate contact of a lateral cross-sectional surface of the second link with the open lever; and a spring interposed between the first link and the second link for applying an elastic spring force to the first link from the open lever, wherein an operational moment for rotating the first link by an operational force reacts in a direction opposite to that of an elastic spring moment for rotating the first link, such that, when an absolute value of the operational moment is greater than an absolute value of the spring moment, a connection point between the first link and the second link rotates by a rotation of the first link about the latch pin, and the lateral cross-sectional surface of the second link contacting the open lever slips on the open lever to rotate the second link relative to the first link, in order to release a contacted state between the open lever and the second link.