| 摘要 |
1,141,499. Pianofortes. NIPPON GAKKI SEIZO K.K. 15 Dec., 1966 [21 Dec., 1965; 27 Dec., 1965; 29 Dec., 1965; 15 Feb., 1966; 11 Oct., 1966], No. 56150/66. Heading G5J. In a sounding board assembly 11 which consists of longitudinal board elements preferably of spruce or maple 11b glued together, at least one bridge 14 and ribs 13, the rigidity of the peripheral portion is reduced. The reduction may be effected by decreasing the thickness of the board and ribs at 11a and 13a or there may be a peripheral groove (15) (Fig. 7, not shown) in the sounding board. The bridge is located so that it is substantially equidistant from the areas of reduced rigidity on either side of it-at least in the low and intermediate tone regions of the sounding board. The wood of the board elements of the central portion of the sounding board may be denser than that of the other board elements made of the same wood. Alternatively, different and denser wood may be used in the central portion. The sounding board is supported at its periphery by a frame (22) (Fig. 13, not shown) which may have a strut (20) to provide additional support. The frame may be drilled with holes (23) (Figs. 13, 14, 15, 16, not shown) where the ribs are supported to reduce its rigidity. |
