Abstract: A movable contacting device in a circuit breaker comprises: a crossbar linked with the opening/closing mechanism and carried so as to pivot cooperatively with the opening/closing mechanism; a movable contact arm engaged, so as to cooperational with the crossbar, with a shaft fitted into a mutually opposing recesses in the crossbar; and a movable contact arm support fixed to the case accomodating the opening/closing mechanism and having mutually opposing through-holes through which the shaft is passed; and the movable contact being configured so that the movable contact slides between surfaces of movable contact arm support having the mutually opposing through-holes; and the construction of a single-pole portion of the movable contact arm is constituted by arranging in parallel two movable contact arm members each having a movable contact at one end, and in a shaft-supporting portion at the other end, an elastic member is sandwiched between the two movable contact arm members.

Abstract: A circuit breaker is comprised of a make-and-break mechanism part disposed between frame plates opposite to each other; a base in which a breaking portion including cross bar, moving contact, fixed contact and arc-extinguishing device, and an over-current trip device are contained; a middle base, in which a partition wall separating the breaking portion from the make-and-break mechanism part, and the breaking portion from the over-current trip device, is provided; and a cover for covering the base and middle base. A frame of the make-and-break mechanism part is secured to the base through the middle base, and the secured part of the frame and the inner bottom face of the base are disposed in the proximity.

Abstract: A movable contacting device in a circuit breaker comprises: a crossbar linked with the opening/closing mechanism and carried so as to pivot cooperatively with the opening/closing mechanism; a movable contact arm engaged, so as to cooperational with the crossbar, with a shaft fitted into a mutually opposing recesses in the crossbar; and a movable contact arm support fixed to the case accomodating the opening/closing mechanism and having mutually opposing through-holes through which the shaft is passed; and the movable contact being configured so that the movable contact slides between surfaces of movable contact arm support having the mutually opposing through-holes; and the construction of a single-pole portion of the movable contact arm is constituted by arranging in parallel two movable contact arm members each having a movable contact at one end, and in a shaft-supporting portion at the other end, an elastic member is sandwiched between the two movable contact arm members.

Abstract: A circuit breaker is comprised of a make-and-break mechanism part disposed between frame plates opposite to each other; a base in which a breaking portion including cross bar, moving contact, fixed contact and arc-extinguishing device, and an over-current trip device are contained; a middle base, in which a partition wall separating the breaking portion from the make-and-break mechanism part, and the breaking portion from the over-current trip device, is provided; and a cover for covering the base and middle base. A frame of the make-and-break mechanism part is secured to the base through the middle base, and the secured part of the frame and the inner bottom face of the base are disposed in the proximity.

Abstract: Linked circuit breakers linked with an interlocking lever having hollows respectively receiving each handle of each circuit breaker and having a groove to be fitted in by the connecting pin positioned between each handle are fixed side-by-side. The groove of the interlocking lever has protrusions which make the groove narrower than the diameter of the connecting pin to fix the connecting pin. Thus, the interlocking lever is mounted easily to the handles of the circuit breakers by the connecting pin which inserts through the through holes of the handles.