Patent ID: 7948336

Claim:
A mold cased circuit breaker comprising: a pair of stationary contactors respectively connected to a power source side and a load side within a base on a point symmetric alignment; a pair of side plates each spaced at a predetermined distance apart on the base with the stationary contactors being positioned therebetween; a lever secured at a top end thereof with a handle, rotatably mounted on the side plates and manipulated in a closed state, a tripped state and a reset state; a latch rotatably mounted at one end thereof on the side plates, and rotated by the lever if the lever moves to a reset condition; a latch holder rotatably mounted on the side plates and selectively restraining the other end of the latch; a nail rotatably mounted on the side plates, resiliently supported to the side plates and selectively restraining the latch holder; a shaft unit mounted with movable contactors selectively connected at both ends thereof to the stationary contactors by rotation, discretely arranged from the lever at a lower section of the lever, and rotatably mounted between the pair of the stationary contactors; an upper link hinged at an upper end thereof to the latch; a lower link hinged at an upper end thereof to a lower end of the upper link via a toggle pin, and hinged at a lower end thereof to the shaft unit; a main spring secured at an upper end thereof to an upper end of the lever and secured at a lower end thereof to the toggle pin; and contactor separation means separating the movable contactors from the stationary contactors by cooperating with the lever if the movable contactors and the stationary contactors are engaged; wherein the contactor separation means comprises: a first isolation link hinged at a lower end thereof to the shaft unit and selectively engaged at an upper end thereof with a lateral surface of the lever; a second isolation link centrally formed with an oblong hole accommodating a guide pin protruded on the side plate and linked at one end thereof to an upper end of the first isolation link; and an isolation lever adjacently positioned at one end thereof to the other end of the second isolation link, and so positioned at the other end thereof as to selectively engage with the nail, and rotatably mounted at the side plates to rotate the nail by way of operation of the second isolation link.