Patent ID: 7956307

Claim:
A circuit breaker having an automatic release linkage including a movable conduction unit ( 3 ) for selectively conducting a first terminal ( 2 ) and a second terminal ( 1 ) by contacting the second terminal ( 1 ) while being electrically contacted to the first terminal ( 2 ), and an open/close linkage including a connection linkage ( 140 ) for transmitting a impact force from the movable conduction unit ( 3 ) to a trip roller ( 55 ) as an operational force, the circuit breaker comprising: an open lever ( 190 ); a second link ( 160 ) rotatably formed about a latch pin ( 150 a ); a third link ( 170 ) having a meshed lateral cross-sectional surface by being latched with an outer circumferential surface of the open lever ( 190 ) while moving relative to the second link ( 160 ) by rotatably fixing the trip roller ( 55 ); and a spring ( 180 ) so interposed between the second link ( 160 ) and the third link ( 170 ) as to apply an elastic force (Fs) toward an operational line ( 99 ), wherein a branch force ( 77 p ) toward the operational line of an operational force ( 77 ) reacts in opposition to the elastic force (fs), and a latched state of a lateral cross-sectional surface of the third link ( 170 ) with the open lever ( 190 ) is released at all times under any circumstance when the branch force ( 77 p ) is greater than the elastic force (fs) by a predetermined level.