Circuit breaker with arc quenching device and vent

A circuit breaker comprising:

• a stationary contact member bent back into a U-shape and having a stationary contact at a bent back portion thereof;
• a moving contact member situated adjacent to the stationary contact member to be able to contact with the stationary contact;
• a plurality of grids laminated vertically with a space therebetween and situated adjacent to the stationary contact member to surround the same;
• and
• a unitary molded insulator situated around the stationary and moving contact members, said insulator including a pair of side walls facing to each other, a plurality of slots arranged in the opposed side walls to vertically space apart from each other, and a plurality of overhangs unitarily molded with the insulator, each of the overhangs extending between the side walls to surround two slots formed in the side walls and facing with each other to form a space in the overhang so that one of the grids is inserted into the space and the two slots and is substantially covered by the overhang, said grids being vertically piled and covered by the overhangs.

A circuit breaker comprising:

• a stationary contact member bent back into a U-shape and having a stationary contact at a bent back portion thereof;
• a moving contact member situated adjacent to the stationary contact member to be able to contact with the stationary contact;
• a plurality of grids laminated vertically with a space therebetween and situated adjacent to the stationary contact member to surround the same;
• a unitary molded insulator situated around the stationary and moving contact members, said insulator including a pair of side walls facing to each other, and a plurality of slots arranged in the opposed side walls to vertically space apart from each other and extending from one end surface of the insulator toward the other end surface thereof so that the grids are inserted into the slots and vertically piled together;
• and
• a protection board attached to said one end surface so that the grids inserted into the slots are fixed and pressed by the protection board mounted on the insulator, said protection board having a gas exhaustion valve having flexibility so that an arc gas generated at a time of breaking of electric current is exhausted by deformation of the exhaustion valve.

A circuit breaker comprising:

• a stationary contact member bent back into a U-shape and having a stationary contact at a bent back portion thereof;
• a moving contact member situated adjacent to the stationary contact member to be able to contact with the stationary contact;
• a plurality of grids laminated vertically with a space therebetween and situated adjacent to the stationary contact member to surround the same;
• a unitary molded insulator situated around the stationary and moving contact members, said insulator including a pair of side walls facing to each other, and a plurality of slots arranged in the opposed side walls to vertically space apart from each other so that the grids are inserted into the slots and vertically piled together;
• and
• auxiliary side walls installed in a space between the side walls of the insulator so that the space inside the insulator is adjusted.