| 摘要 |
<p>PURPOSE: To reduce a manufacturing cost by simplifying the constitution of backposts, soundboards and frame peripheries with substantially no degradation in acoustical characteristics. CONSTITUTION: Since the piano 2 is formed by screwing the soundboards 22 to a frame 4, the need for the backposts and ribs is eliminated and the cost is reduced. Particularly, the ribs are required to be precisely formed and further, the precise mounting of the ribs is needed in the case of mounting the ribs to the backposts, for which extreme skill is needed and such ribs are heretofore obstructive for the cost reduction. The frame 4 in common use as the backposts and ribs is a casting having extremely high rigidity and is formable relatively easily by precision integral molding. The arbitrary setting of its strength by designing is possible as well. The frame 4, even formed to a shape different from the shape of the conventional frame 4, is not a factor for a significant cost increase. The cost reduction resulted from the saving of the two kinds of the parts, the backposts and particularly the wooden ribs having the hardness, and of their assembly stages more than compensates such cost increase. Projections, protruded lines or grooves may be provided on the fitting surface of the soundboards 22.</p> |
