Optically coded keyboard arrangement

US4247211A · kind A · utility

Assignee

• Olympia Werke AG · DE

Inventors

• Wolfgang Behrendt · Wilhelmshaven, DE
• Detlef Bohnhage · Wilhelmshaven, DE
• Peter Friedemann · Philo, US
• Bernhard Frolich · Homberg (Efze), DE
• Reinhold Orzessek · Schortens, DE

Key dates

• Filing date: Mar 2, 1979
• Grant date: Jan 27, 1981
• Expiry date: Mar 2, 1999

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B41J5/08
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

An optically coded keyboard arrangement has a plurality of key units arranged to be individually actuated; an actuation sensing arrangement that includes a plurality of light emitters generating light beams and a plurality of detectors each placed in the path of a respective light beam. Each key unit includes a key arranged to be depressed and a coded mask coupled to the key for movement with the key in unison upon displacement of the key and for movement relative to the key in a direction transverse to the path of motion of the key. Each key unit further has a switching spring which, in the position of rest of the associated key has an arcuate shape bulging in one direction and engages at one end a countersupport. As the key is depressed, the switching spring is deformed into a more bulging shape, carrying the mask into a position where it is ready to interrupt the light beams. Upon continuing movement of the key by virtue of the depressing force, a cam causes the tensioned switching spring to jump off the countersupport, whereupon the spring, as it assumes a released state, rapidly moves the mask into the light beam paths.