Momentary "on" switch suitable for keyboards

Claim 1

In a keyboard having a baseplate; a key having a keytop on which is an actuation surface; a key support projecting from said baseplate and maintaining said key in translational sliding relation with said support along an actuation path approximately normal to the baseplate with the actuation surface facing away from the baseplate; a movable conductive contact shifting with the key's translation along the actuation path; a fixed conductive contact in the path of and facing the movable conductive contact and making electrical contact with the movable electrical contact when force on the keytop causes the movable conductive contact to approach the baseplate; and a spring contacting both the key and the baseplate to urge the key away from the baseplate, an improved arrangement of the keyboard's elements wherein the support comprises a cylindrical projection having an end spaced from the baseplate, an axis extending along the actuation path, and a bore extending along the actuation path from the end of the projection toward the baseplate; wherein the key includes a projection extending from a surface of the key opposite the actuation surface, said key projection's external surface conforming with the cylindrical projection's bore so as to guide translation of the key along the actuation path; wherein the key projection and cylindrical projection cooperatively comprises a means for retaining the key projection within the bore of the cylindrical projection; and wherein the spring comprises a resilient boot in surrounding relation to the cylindrical projection, said boot having an aperture through which the key projection passes; said improved arrangement further including a membrane having an aperture through which the cylindrical projection passes, said membrane carrying the fixed electrical contact at a point adjacent both the cylindrical projection and the baseplate.