| 摘要 |
<p>PROBLEM TO BE SOLVED: To make it easy to open and close a fallboard, to reduce the burden on a user, and to improve the safety. SOLUTION: A piano main body 1 and the fallboard 2 are connected to each other by a rotary buffer device 20. The buffer device 20 is provided with a cylinder 21 filled with damping oil and a rotor which is stored rotatably in the cylinder 21, fallboard-side arm 29 projectingly provided in the cylinder 21 is connected rotatably to the reverse surface to the fallboard 2, and a main- body side arm 41 fixed onto a rotor side is connected rotatably to a metal fitting 43 provided in a lib 42A of a frame 42. Since buffer device 20 is small in the viscous resistance of the damping oil when the fallboard 2 is opened, no large resistance is generated and the fallboard can easily be opened, and since the viscous resistance of the damping oil is large when the fallboard is closed, the fallboard 2 is damped and stopped from abrupt rotating.</p> |
