Patent ID: 6130371
Filing Date: 2000-10-10
Classification: G10C

Abstract:
A fall board structure of a keyboard instrument comprising:a fall board which rotates about a rotation axis portion provided in connection with a main body of the keyboard instrument, so that the fall board can be opened or closed;a torque shaft unit, having a shaft portion having a capability of free rotation, which produces resistance force against rotation of the shaft portion; anda rotation member being engaged with the shaft portion of the torque shaft unit, the rotation member having a capability to lock the shaft portion with respect to the torque shaft unit,wherein one of the torque shaft unit and the rotation member is fixed to the main body of the keyboard instrument while another one of the torque shaft unit and the rotation member engages with the fall board which is placed in a close operation process to rotate about the shaft portion of the torque shaft unit so that the torque shaft unit produces resistance force, which is transmitted to the fall board, andwherein as the fall board rotates deeply in a close operation direction thereof, an increase ratio of a rotation angle of said another one of the torque shaft unit and the rotation member against a rotation angle of the fall board is increased larger.