| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain an opening/closing device for a cap capable of opening and closing a roof plate by diving and opening the cap at a desirable angle by providing the decide with a transforming mechanism which is housed in a reduced state in a keyboard musical instrument and is extended to push up the cap by rotation of a motor. SOLUTION: When an open button is pushed, a controller runs the motor 12 and a worm gear 13 revolves. A feed nut 14 moved toward the right side of Fig. along its screw. Two arms 15, 15 are turned to be opened, the roof plate 2 is pushed up. The controller controls the revolution of the motor 12 in accordance with the signal outputted from a rotary encoder is such a manner that the roof plate 2 attains the angle set by a sliding key. Since the roof plate (cap) 2 is opened and closed by the driving power of the motor 12, the device is extremely convenient. Since the angle to open the roof plate 2 is arbitrarily selectable to meet the area of hall where playing is performed or the selected music, etc., a desired acoustic effect is obtainable.</p> |
