Patent Document ID: 4217803
Application ID: 06000588
Patent Flag: 1

Claim One:
1. A piano-action keyboard for an electronic musical instrument comprising a plurality of elongated keys, a supporting base, each of said keys being pivotally mounted on said supporting base, a plurality of arms pivotally mounted on said base, each arm being adjacent one end of a key and arranged so that when the key is pivoted, a driving force is imparted to the adjacent arm by direct striking of the arm by the key at a strike point, electrical signal means comprising a mechanical component mounted on each said pivoted arm and plural portions of said signal means each of which is responsive to movement of one said arm to generate an electrical signal as the associated arm moves including response to rate of movement of the arm means defining an interface between each key and pivot-arm pair which varies the force resolution components of the force transmitted to the arm by key pivoting so that an initial stage of key pivoting from an at rest position produces lower Fy and higher Fx components where y is the direction of movement of the arm portion at the strike point and y is the orthogonal to x compared to Fx and Fy at a later stage of key depression.