US 5,034,573 AGranted

Contact-type keyboard

AssigneeIng. C. Olivetti & C., S.p.A.

InventorsGianpaolo Bonmassari, Claudio Gillio

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Abstract

The contact-type keyboard comprises a plurality of keys which are movable from a rest position to an operative position and which each have a sleeve capable of being accommodated in a tube provided on the upper part of a dome portion of elastomeric material. Each dome portion projects from a mat and, below the tube, comprises an internal circular ring provided with a movable conductive portion for short-circuiting a corresponding fixed conductor of a printed circuit which in turn is carried by a stop plate of insulating material. Each sleeve is of such a length as to pass internally by way of an upper opening through the dome portion, to engage a through hole in the plate to project downwardly beyond the plate and comprises a seat capable of accommodating a corresponding pin of a support frame structure so as to guide the respective key from the rest position to the operative position and vice-versa. The support frame structure is positioned below the stop plate at a predetermined spacing such that it does not interfere with the end of the sleeve when the respective key is in the operative position. The key is in turn restrained to the plate by means of a lateral appendix which is freely accommodated by a seat in the plate and provided with a hook portion which is retained by the plate.

Claims15

Dependent claims

A contact-type keyboard comprising:

a support plate;
an insulating plate restrained with respect to said support plate and having a plurality of fixed seats formed therein;
a plurality of fixed contacts carried by said insulating plate and fixed with respect to said support plate;
a plurality of keys movable from a rest position to an operative position and each including an actuating element and a hooking extension engageable with one of said plurality of fixed seats;
a plurality of movable contacts;
a plurality of dome elements of elastomeric material each of which is interposed between the actuating element of a respective one of said plurality of keys and one of said plurality of movable contacts;
each of said plurality of dome elements being capable of elastic deformation in response to the movement of said actuator element to bring said corresponding movable contact into contact with one of said plurality of fixed contacts;
each of said dome elements having formed therein an upper opening;
a plurality of first guide members on said support plate each of which said first guide members projects towards one of said plurality of dome elements;
and
a corresponding plurality of second guide members each of which is guided slidably by one of said plurality of first guide members;
whereby said plurality of keys are restrained with respect to said support plate by the engagement of said hooking extensions with said fixed seats;
and movement of each of said keys between said rest position and said operative position is guided by the slidable engagement of said respective first and second guide members, said second guide member passing through the upper opening of the dome element associated with said key.

10 more elements

Dependencies are inferred from the claim text.