Operating key switch unit

Claim 1

An operating key switch unit having an electric circuit enclosed in a waterproof case and a plurality of key switch buttons exposed on a front surface of the case, the operating key switch unit comprising: a printed circuit board mounted in the case by plurality of bolts for partitioning the interior of the case into a front portion and a back portion; a plurality of circuit board contacts formed on said printed circuit board in said front portion; a plurality of key switch buttons adjacent to said plurality of circuit board contacts for developing a connection thereto; a plurality of electronic parts disposed on said printed circuit boards in said back portion; a switch panel integrally formed with and connected to said plurality of key switch buttons, said switch panel having a flexible and elastic portion formed around said plurality of key switch buttons; a first contactor extending from the front surface of the case into said front portion and annularly surrounding said plurality of key switch buttons; and a second contactor protruding from said switch panel and forming a generally U-shaped section having a top part of the vertical legs of said U-shaped section having a more constricted separation than a bottom part of the vertical legs of said U-shaped section for providing a hermetical seal for said plurality of key switch buttons by continually contacting said first contact at both side portions thereof and at a right angle to the axis in which the key switch buttons are depressed.