| 摘要 |
PURPOSE: To provide a key touch detector which is easily and exactly mountable at a keyboard musical instrument, such as piano. CONSTITUTION: Light emitting elements 3a, 5a and light receiving elements 3b, 5b constituting two sets of key sensors 3, 5 are arranged to face each other across a slit 7a of a casing 7. A stepped shutter 11 is oscillatably fixed via s shaft member 13 atop the casing 7. The stepped shutter 11 is held energized upward by a torsional coil spring 15. The outputs of the key sensors 3, 5 change successively and the action of a key is detected when the front end face 11b of the stepped shutter 11 is pressed by the rear surface of the key at the time of key touch. Since the key sensors 3, 5, the stepped shutter 11 and the torsional coil spring 15 are integrated via the casing 7, the easy and exact mounting of the detector at the piano is possible. |
