Patent ID: 7019225

Claim:
A depression responsive switch unit in which a switch is turned on in response to a depression operation; comprising a case including a surface plate in which an opening is formed; a reinforcing plate disposed opposite to a rear plate of the case and disposed within the case so as to be reciprocable with respect to the rear plate; a second step switch interposed between the reinforcing plate and the rear plate and adapted to be operated on by a movement of the reinforcing plate toward the rear plate; a plurality of first step switches disposed on the reinforcing plate on the side located toward the surface plate; a key operation base disposed on the case in a manner to block the opening in the surface plate and formed with depression openings each located corresponding to each first step switch; and a knob disposed on the key operation base on the opposite side from the reinforcing plate; the knob including an elastic sheet which is formed of a thermoplastic elastomer or a silicone rubber and having a marginal portion which is retained by the case, depressing pieces formed on the elastic sheet in a manner corresponding to each first step switch and having a depressed surface on the front side of the elastic sheet and disposed in each depression opening, and a small projection projecting from each depressing piece in the opposite direction from the depressed surface to be located close to or in contact with the first step switch.