Electrical compression switch

Claim 1

In an electrical switch of the type wherein for quenching the arc drawn in a gap formed between the switch contacts as they disengage a gaseous quenching medium is caused to flow into the gap, the combination comprising a switch casing, a pair of switch contact members supported within said casing, at least one of said contact members including driving means for effecting engagement and disengagement with the other contact member, a piston and cylinder unit for pre-compression of the gaseous quenching medium, means forming a passage for delivering the gaseous medium compressed by said piston in said cylinder to the gap formed between said contact members as they disengage, an energy storing device correlated to said piston, and means for coupling said driven contact member to said piston and to said energy storing device only when said driven contact member moves in the contact-engaging direction thereby to store energy and simultaneously move said piston in one direction to a position within said cylinder in which the gaseous medium enters said cylinder through valve means, said piston being freed for movement in the opposite direction by the stored energy upon movement of said driven contact member in the contact-disengaging direction thereby to effect compression of the gaseous medium and discharge the same from said cylinder through said passage to the gap formed between said contact members.