Keyboard assembly with foldable printed circuit matrix switch array, and key actuator locking slide plate

Claim 1

A keyboard assembly comprising: a. a flat flexible cable with a portion thereof folded back over on itself and having contacts deposited on both facing surfaces, contact on one surface being directly across from contacts on the other surface; b. means for connecting the contacts into electrical circuits; c. a layer of insulating material positioned between the two contact-carrying surfaces and having holes therethrough, said holes being in registration with opposing contacts; d. a switch plate overlying the folded over cable and containing a plurality of resilient switch members comprising an elongated limb extending obliquely upwardly and a pair of fingers, one on either side of the limb, extending obliquely downwardly with the free end of each finger being adjacent an outside surface of the folded over cable and in direct alignment with a contact located on the inside surface, said plate further containing a plurality of commoning members comprising an L-shaped strip of material having a vertical arm and an elbow, said elbow being adjacent an outside surface of the folded over cable and in direct alignment with a contact located on the inside surface; e. a slidable cam plate positioned over and spaced from the switch plate, said cam plate having a plurality of slots into which the vertical arms extend and a plurality of openings in alignment with each of the switch members; f. a plurality of movable keys each having a bottom surface adjacent the free end of the limb on the switch member anD a beveled surface on one side so that as one of the keys are depressed, the bottom surface thereof pushes downwardly on the limb whereby the two free ends on the fingers pushes the cable forcing the underlying aligned contacts into electrical engagement through a hole in the layer of insulating material, said beveled surface concurrently pushing on and laterally sliding the cam plate such that the arms of the commoning members extending through the slots are rotated about the point of attachment with the switch plate so that the elbows drive the underlying contacts into electrical engagement through the holes in the insulating layer.