Typewriting machines – Key-board or key lever-actuating mechanism – Including means generating a signal for type selecting or...
Patent
1984-05-24
1985-08-13
Burr, Edgar S.
Typewriting machines
Key-board or key lever-actuating mechanism
Including means generating a signal for type selecting or...
340365P, B41J 508
Patent
active
045346682
ABSTRACT:
A photoelectric keyboard for typewriters and similar machines comprises two parallel plate modules spaced one above the other, the upper plate module comprising a plate of transparent material having holes supporting and guiding light transparent depressible key stems, and having cutouts supporting light sources, and the lower plate module comprising a printed circuit board supporting photo elements opposite the ends of key stems. The ends of the transparent key stems are, in normal position, spaced a predetermined optical distance from the photo elements arranged on the lower plate such that the light radiated from the ends of the key stems is insufficient to activate associated photo elements. On depressing a key, the distance between the end of the key stem and an associated photo element is reduced and the light beam radiated from the end of the key stem is sufficient to activate the associated photo element. Thus only the corresponding photo element is activated by a depressed key.
REFERENCES:
patent: 3372789 (1968-03-01), Thiele et al.
patent: 3603982 (1971-09-01), Patti
patent: 3676689 (1972-07-01), Knepper, Sr.
patent: 3856127 (1974-12-01), Halfon et al.
IBM Technical Disclosure Bulletin, vol. 15, No. 11, Apr. 1973, _pp. 3348-3349, "Miniature Optical Keyboard", by Ludeman.
Hildel Heinz
Schnell Wolfgang
Westphal Gerald
Burr Edgar S.
Pearson Charles A.
Spalla Joseph R.
Triumph-Adler Aktiengesellschaft fur Buro- und Informationstechn
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