Patent ID: 7973233
Filing Date: 2011-07-05
Classification: G10C,G10F,G10H

Abstract:
1. A musical tone control system for a grand-type piano including a pivotally movable key, and a hammer which has a hammer shank on which a shutter extending in a front-rear direction of the piano and protruding upward is integrally mounted, comprising: a first, a second, and a third optical sensor provided above the hammer and arranged in a direction of the length of the hammer shank, each of which has a light emitting part disposed on one side of a pivotal motion path along which the shutter is pivotally moved, for emitting light; a light receiving part disposed on another side of the pivotal motion path for receiving the light from the light emitting parts, and outputting a detection signal indicative of a light receiving state of the light receiving parts dependent on whether or not an optical path of the light from each of the light emitting parts is opened or closed by the shutter pivotally moving along the pivotal path; key depression-determining means for determining, based on a detection signal from said first optical sensor, depression or non-depression of the key; pivoting direction-determining means for determining a pivoting direction of the hammer based on a detection signal from only said second optical sensor; pivoting speed-calculating means for calculating a pivoting speed of the hammer based on a detection signal from only said third optical sensor; and control means for controlling a musical tone to be sounded, based on the determined depression or non-depression of the key and the determined pivoting direction of the hammer, and the calculated pivoting speed of the hammer.