Patent ID: 8624140

Claim:
A key switch comprising: a base section; a key top disposed above said base section; a pair of link members interlocked to each other to support and direct said key top in a vertical direction relative to said base section; a switch member including a contact section capable of opening and closing in response to a vertical movement of said key top; a biasing member capable of applying an elastic biasing force in a vertically upward direction to said key top; and an annular protection member including a tubular part having an open top end, the annular protection member being disposed and inserted between said base section and said key top at a position where said protection member surrounds said pair of link members, said contact section and said biasing member, the tubular part being disposed on a sheeting part of the annular protection member, the sheeting part further including an annular projection spaced apart from an outer periphery of the key top in an outward direction generally parallel to an operating surface of the key top, said key top including pivot support sections pivotably supporting said pair of link members, the open top end of said tubular part of said annular protection member contacting an inner surface of said key top at a location outside said pivot support sections, and said protection member being elastically deformed to follow said vertical movement of said key top and protecting said pair of link members, said pivot support sections, said contact section and said biasing member from penetration of foreign matter.