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US 4,117,438 AGranted
Contactless keyswitch for keyboards
AssigneeDatanetics Corporation
InventorsKirk J. Kim, Michael Muller
Life of this patent
Estimating the term…
Abstract
Inductive sensing keyswitch includes a printed circuit transformer and sheet of material having hinged metal flaps formed therein and each flap is resiliently biased against both printed circuit coils of the transformer for eddy-current shorting of both coils wherein keys on the keyboard have key stems passing through the printed circuit board between the printed coils and the flap hinges to provide a mechanical advantage for moving the flaps away from the printed circuit coils a greater distance than the short stroke movement of the key.
Claims12
A contactless keyswitch comprising:
- a circuit board having at least one reactive circuit element formed thereon;
- a sheet of material secured to said circuit board, said sheet including at least one movable, electrically conductive flap formed integrally therein, said flap being disposed opposite said circuit element and biased toward the circuit element;
- and keyswitch actuating means coupled to said flap to move the flap away from the circuit element to cause a change in reactance of said circuit element upon actuation of said switch.
A keyboard comprising:
- a circuit board;
- a plurality of keyswitch actuating means disposed on one side of said board, said actuating means including keys and keystems located to pass through corresponding apertures in said board upon actuation thereof;
- a plurality of circuit elements formed on the opposite side of said board, and a strip of resilient material secured to said opposite side and over said circuit elements;
- said strip of material including partially severed areas forming a plurality of flaps, said flaps being located opposite respective ones of said circuit elements, said flaps being hinged along unsevered portions integral with said strip and resiliently biased by said portions against respective circuit elements;
- said flaps including electrically conductive material for changing the reactance of opposing circuit elements in response to operation of said keyswitch actuating means having keystems located to engage and move respective ones of said flaps.
2 more elements
Dependencies are inferred from the claim text.