Abstract: A switch comprises an envelope including a pressure increasing compartment filled with an arc extinguishing fluid. A slit extends through one longitudinal side of the envelope to communicate with the compartment. A movable contact member having a flat cross section normally extends through the slit to block substantially the slit until the movable member engages a stationary contact member outside of the slit. The arc extinguishing fluid increases in pressure in response to heat of an electric arc established across the separated contact member and delivered through the slit to be perpendicular to the arc axis.

Abstract: An outer arc extinguishing compartment is disposed coaxially with an inner arc extinguishing compartment and partly projects under one end thereof. A movable contact member extends through both compartments and separably engages a stationary contact member located within the inner compartment. A plurality of arc suppressors of spindle-shaped cross section are disposed at equal angular intervals in the projecting portion of the outer compartment adjacent to and about the movable contact member to extend axially and radially of the latter. The circumferential minimum distance between the arc suppressors is smaller than the diameter of a positive column of an electric arc struck across both contact members.