Key switch

DETAILED DESCRIPTION The present invention has been accomplished to provide a key switch which eliminates the aforesaid drawbacks.
It is therefore an object of the present invention to provide a key switch which produces little friction force during its operation so that the movement of the key body thereof is smoothed.
It is another object of the present invention to provide a key switch which eliminates the formation of a vacuum during its operation.
It is still another object of the present invention to provide a key switch which is inexpensive to manufacture and easy to assemble.
To achieve the aforesaid objects, there is provided a key switch comprised of a square key base having an inward facing top flange around the four sides thereof, four 45.
degree.
angle bevel edges on the inward facing in the four corners thereof, and four notches on the inward facing flange in the middle of either side thereof; a key base having four air passage holes longitudinally disposed in the four corners of the square center through-hole thereof, four cylindrical flanges longitudinally raised from the four corners thereof and side-matched with either 45.
degree.
angle bevel edge on the inward top flange of the key base, four stub rods respectively extended down from the cylindrical flanges and stopped below the inward top flange, and a projection raised from one side thereof in the middle at the top and vertically disposed in line with one notch on the inward top flange of the key base for guiding vertical movement of the key body within the key base; and a key cap having a plunger fitted into the square center through-hole on the key body and moved to compress a rubber cone below in triggering a circuit, and a inside hole on the plunger communicating with the air passage holes for exhaust of compressed air.
Because the cylindrical flanges of the key body are respectively disposed in contact with the key base at three contact points, less friction force is produced when the key body is moved relative to the key base