Patent ID: 8809720

Claim:
An arc extinguishing mechanism for a mold cased circuit breaker comprising a plurality of arc grids stacked one-by-one perpendicular to a bottom of the arc extinguishing mechanism and supporting plates that support the arc grids in order to form an arc chamber, wherein each of the plurality of arc grids comprises: a U-shaped plate portion made of a ferromagnetic material and comprising a pair of divided leg portions that form a rectangular gap between the pair of leg portions and a flat surface; a plurality of supporting protrusions laterally extending from the plate portion to such that they are flush with the plate portion and allow the plate portion be installed to and supported by the supporting plates; and a pair of bent portions vertically bent and extending from the pair of divided leg portions, wherein each of the pair of bent portions is physically separated from the other of the pair of bent portions by a substantially continuous predetermined distance and a top surface of one of the pair of bent portions faces a top surface of the other of the pair of bent portions such that a force for inducing an arc generated in the arc chamber toward the plurality of arc grids is increased.