| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide the pin plate structure of a piano which can always hold the clamping torque of a tuning pin nearly constant. SOLUTION: A pin plate 3 has plywood structure having longitudinal core veneers 31 and lateral core veneers 32 stacked by turns. A sheet 33 of glass fiber is adhered between a longitudinal core veneer 31 and a lateral core veneer 32 which face each other. Even if the longitudinal core veneers 31 and lateral core veneers 32 of the pin plate 3 are to expand by varying in water content, glass fiber sheets 33 prevent them from expanding or contracting. Consequently, a hole 2 has a little variation in diameter even when the pin plate 3 varies in water content and the clamping torque of the tuning pin 1 is always held almost at an initially set value.</p> |
