| 摘要 |
<P>PROBLEM TO BE SOLVED: To save a space of an instrument casing, to restrain a sudden change in load in the middle of opening and closing operation in a split-type cover, and to lighten the cover opening operation. <P>SOLUTION: The cover 30 includes a front cover 31 and a rear cover 32, which are adjacent in front and behind in closing the covers and superposed on the rear part of the casing of a keyboard instrument 10 in opening the covers. A rotor 50 includes a large wheel 51 and a small wheel 52, which are different in outside diameter, concentric and rotated in a body. Wires 53, 54, the respective one ends of which are fitted to a rear end 31a of the front cover 31 and a rear end 32b of the rear cover 32, are wrapped round the large wheel 51 and the small wheel 52 from the upside, and the respective other ends hung downward are provided with plumbs 55, 56. Torque is applied to the rotor 50 by the plumbs 55, 56. The wires 53, 54 are displaced forward and backward by an amount corresponding to the movement of the outer peripheries of the large wheel 51 and the small wheel 52. The front cover 31 and the rear cover 32 are subjected to energizing force in the cover opening direction by torque applied to the rotor 50. <P>COPYRIGHT: (C)2010,JPO&INPIT |
