Pressure-compensated key switch

A key switch comprising:

• a housing having an exterior, a hollow interior, a key aperture, and two pivot supports, one pivot support on each side of the key aperture;
• a flexible membrane that covers the key aperture on the exterior of the housing;
• a key body having an elongated body, a top, a bottom, two sides, and two opposite ends, the key body comprising:
• a first and a second key surface on the key body top in each opposite end, where the key surfaces (i) extend through the key aperture in the housing to be adjacent to the flexible membrane and (ii) have approximately equal surface areas;
• a first and a second switch driver on the key body bottom in each opposite end;
• and
• two pivot pins, one on each side of the key body, positioned approximately mid-way between the two key surfaces, the pivot pins supported and free to rotate on the pivot supports in the housing;
• a switch support mounted to the hollow interior of the housing;
• and
• a first and a second switch mechanism, each with a top and a bottom, the bottoms being supported by the switch support, the tops adjacent to first and second switch drivers, respectively, where the switch mechanism actuates when compressed between the switch driver and the pivot/switch support;
• whereby, a light force applied through the flexible membrane upon one of the key surfaces will cause the key body to rotate about the pivot pins supported by the pivot supports to cause one of the switch drivers to exert a compressing force on one of the switch mechanisms so that the switch mechanism actuates, and whereby a large pressure applied through the flexible membrane upon both of the key surfaces approximately equally will not actuate either of the switch mechanisms.

A key switch comprising:

• a housing having an exterior, a hollow interior, and four key apertures spaced apart from each other;
• a flexible membrane that covers the four key apertures on the exterior of the housing;
• a pivot/switch support mounted to the hollow interior of the housing;
• a key body having a cross shaped body with a first and a second pair of opposite ends, a top, and a bottom, the key body comprising:
• a first and a second key surface on the key body top in the first opposite ends, where the key surfaces (i) extend through the key apertures in the housing to be adjacent to the flexible membrane and (ii) have approximately equal surface areas;
• a third and a fourth key surface on the key body top in the second opposite ends, where the key surfaces (i) extend through the key apertures in the housing to be adjacent to the flexible membrane and (ii) have approximately equal surface areas;
• a first, a second, a third, and a fourth switch driver on the key body bottom in each of each pair of opposite ends;
• and
• a pivot point on the key body bottom, located approximately at the intersection of the line joining the centers of the first and second key surfaces with the line joining the centers of the third and fourth key surfaces, the pivot point to have a point of contact with the pivot/switch support;
• and
• a first, a second, a third, and a fourth switch mechanism, each with a top and a bottom, the bottoms being supported by the pivot/switch support, the tops adjacent to first second, third, and fourth switch drivers, respectively, where the switch mechanism actuates when compressed between the switch driver and the pivot/switch support;
• whereby, a light force applied through the flexible membrane upon one of the key surfaces will cause the key body to pivot about the point of contact between the pivot point and the pivot/switch support and cause one of the switch drivers to exert a compressing force on one of the switch mechanisms so that the switch mechanism actuates, and whereby a large pressure applied through the flexible membrane upon all four of the key surfaces approximately equally will not actuate any of the switch mechanisms.

A key switch having n keys, where n is two or more, comprising:

• a housing having an exterior, a hollow interior, and n key apertures spaced apart from each other;
• a flexible membrane that covers the n key apertures on the exterior of the housing;
• a pivot/switch support mounted to the hollow interior of the housing;
• a key body having a body, a top, a bottom, and n ends, the key body comprising:
• n key surfaces on the key body top in each of the n ends, where the n key surfaces extend through the n key apertures in the housing to be adjacent to the flexible membrane;
• n switch drivers on the key body bottom in each of the n ends;
• and
• a pivot point on the key body bottom, at a selected position that is the area-weighted center of gravity of the n key surfaces, the pivot point to have a point of contact with the pivot/switch support;
• and
• n switch mechanisms, each with a top and a bottom, the bottoms being supported by the pivot/switch support, the tops adjacent to the n switch drivers, respectively, where the switch mechanism actuates when compressed between the switch driver and the pivot/switch support;
• whereby, a light force applied through the flexible membrane upon one of the key surfaces will cause the key body to pivot about the point of contact between the pivot point and the pivot/switch support and cause one of the switch drivers to exert a compressing force on one of the switch mechanisms so that the switch mechanism actuates, and whereby a large pressure applied through the flexible membrane upon all n of the key surfaces approximately equally will not actuate any of the switch mechanisms.