Keyboard actuable with the aid of the fingers of at least one hand

An individual actuating key unit for use in a keyboard, actuatable with the aid of fingers of at least one hand, which unit comprises a supporting frame, a key having a top face destined for having the tip of a finger rest thereon, a key rod on the underside thereof, a non-depressable mounting whereby said key rod is mounted in said supporting frame and is disposed in a rest position at right angles to a bearing plane of said supporting frame, at least one contact switch having a stationary and a movable contactor, said key rod bearing said movable contactor near the tiltable key-bearing end thereof, an electrical operating circuit into which said switch is inserted, said switch being opened in a rest position of the key without making contact, thereby interrupting the flow of current through said operating circuit, and being closable by movement of said key away from said rest position, thereby making contact and thereby closing said operating circuit, said key being advised to have the tip of the finger used for actuating the key rest thereon and capable of supporting random vertical pressure thereon by said finger-tip without having said key rod making electrical contact, and said movable contact being so disposed on said key rod as to make electrical contact when said key and key rod are tilted out of their rest position by means of movement of the fingertip, said actuating unit further comprising a return device for moving the key from an actuated position into the rest position, the return movement of which device is positively initiated immediately upon completion of contact-making by the key, even when the finger-tip continues to exert actuating pressure, said return device comprising means for limiting movement whereby the positively returned key is arrested and retained in its rest position, and is positively prevented from passing through the latter in the direction toward another contact.