Patent ID: 8314355

Claim:
A puffer type gas insulated breaker used in a power system comprising: a puffer cylinder which compresses an insulation gas and extinguishes an arc and which has a slide contact portion; and a contact finger which has a slide contact portion which may be brought into slide contact with the slide contact portion of the puffer cylinder in the inside of a vessel in which the insulation gas is sealed, wherein a relatively soft silver plating film is formed on the slide contact portion of the puffer cylinder and a relatively hard silver plating film, which is harder than the relatively soft silver plating film, is formed on the slide contact portion of the contact finger, wherein the thickness of the relatively hard silver plating film is less than the thickness of the relatively soft silver plating film, and wherein one of the relatively soft silver plating film and the relatively hard silver plating film is formed of an inner plating film and an outer plating film, the inner plating film being softer than the outer plating film.