Patent ID: 6805507
Filing Date: 2004-10-19
Classification: H01H

Abstract:
A keyboard device comprising:a substrate subjected to a single punching operation so as to form said substrate with a plurality of punched holes, each of which has a first side and a plurality of positioning members, each of which includes an upright first wall portion that extends from said first side of a corresponding one of said punched holes, and a second wall portion that is connected to said first wall portion and that extends parallel to said substrate such that said first and second wall portions cooperate to confine a positioning groove; a membrane circuit provided on said substrate and formed with a plurality of through holes registered with said punched holes in said substrate, respectively, said through holes permitting said positioning members of said substrate to extend upwardly therethrough, said membrane circuit being provided with a plurality of electrical contacts; and a plurality of key units disposed on said membrane circuit and assembled on said substrate, each of said key units including an upright biasing member supported on said membrane circuit and having an actuator registered with a corresponding one of said electrical contacts, a base plate disposed on said membrane circuit and formed with an opening to permit extension of said biasing member therethrough, said base plate having opposite ends, each of which is formed with an outwardly extending positioning block engaged in said positioning groove confined by a corresponding one of said positioning members of said substrate such that said base plate is positioned on said substrate, said positioning block is formed with a positioning post extending downwardly and into a corresponding one of said punched holes in said substrate for positioning said base plate on said substrates; a key cap disposed above said base plate, and a foldable retaining member provided between said base plate and said key cap for retaining said key can on said base plate such that said key cap is movable toward and away from said base plate, said biasing member providing a biasing force for moving said key cap away from said base plate.