JPH0257316B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piano frame structure in which the support frame is eliminated, the soundboard is directly fixed to the frame, a predetermined crown is provided, and the entire weight of the piano is supported by the frame.

The frame of a piano is used to hold strings of each pitch that are stretched with a predetermined tension, and in the case of an upright piano, it is usually constructed as shown in FIGS. 1a, b, and c. That is, the frame 1, which is formed of a casting such as cast iron and has a substantially frame shape, has a tuning pin installation part into which a plurality of tuning pins 2 are driven, each of which locks one end of the string 15 of each pitch. 3. A frame pin installation part 5 into which a plurality of frame pins 4 are driven to respectively lock the other end of each string 15, a punch hole 6 for weight reduction, a reinforcing rib 7, and a string support mount 8, 9. etc., and are arranged substantially vertically within the exterior body 11 of the piano 10. The upper end of the tuning pin 2 is rotatably press-fitted into an insertion hole 13 of a pin plate 12 fixed to the back surface of the tuning pin installation part 3. The strings 15 of each pitch are supported at their intermediate parts by the string rests 8, 9, a long bridge 16 (or short bridge 17) fixed to the surface of the soundboard 28, which will be described later, and the like. The tension is changed by adjusting the rotation of the tuning pin 2, and the pitch is tuned to a predetermined pitch.

At the rear of the frame 1, a support frame 20 is provided as a support member for the frame 1 and the soundboard 28. This support frame 20 includes an upper girder 21,
It is formed into a rectangular frame shape by a middle girder 22, a large base 23, a pair of left and right vertical frames 24 connecting these three, etc., and is erected almost vertically on the bottom plate 25 of the piano 10. The frame 24 is firmly fixed to the inner surfaces of a pair of left and right parent plates 26 that constitute the exterior body 11. Further, the pin plate 12 is fixed to the front upper end of the support frame 20, and the middle girder 22 and the large base 2
3 and the front edges of a pair of left and right vertical frames 24, the peripheral edge portion of the sound board 28 is fixed via a winding 29.

A long piece 16 is disposed approximately at the center of the surface of the soundboard 28, extending over the entire range from the bass to the treble, and supporting the middle and treble strings 15. A short bridge 17 for supporting the bass strings 15 is arranged near the lower peripheral edge. On the other hand, soundboard 28
on the back surface thereof, extending in a direction perpendicular to the grain direction of the soundboard 28, and having both ends connected to the striking 2
A plurality of sound rods 30 fixed to 9 are arranged at predetermined intervals. These sound bars 30 function as a vibration transmission member that transmits the vibration of the strings 15 transmitted to the sound board 28 via the long bridge 16 or the short bridge 17 in a direction perpendicular to the grain direction of the sound board 28. By providing the soundboard 28 with a gentle crown (curve) in which the central portion thereof bulges toward the surface side, the soundboard 28 functions as a strength member that prevents the soundboard 28 from sinking due to string pressure. In addition, the above-mentioned Uchimawashi 29
The surface is formed into a gently curved surface to give the soundboard 28 a predetermined crown.

By the way, in the conventional upright piano 10 having the above-mentioned configuration, the tension of the strings 15 is supported by the frame 1, the support point strength of the soundboard 28 is ensured by the percussion 29 and the support frame 20, and the frame 1 is ,
Since the support frame 20 etc. are supported by the exterior body 11,
It was necessary to firmly connect and fix these three parts to each other. As a result, the structure becomes complicated, the number of gluing points, screwing points, etc. increases, and the assembly work is complicated.
It has the disadvantage of requiring a long time. Also,
Since the support frame 20 and the batten 29 are made of wood, they are susceptible to warping, twisting, etc. due to environmental changes such as temperature and humidity. When attaching the soundboard through the cable, there are many problems in terms of manufacturing technology, such as having to match the actual product to match the crown of the soundboard 28.

Therefore, for example, a frame structure in which the soundboard is directly fixed to a frame-shaped projecting body provided integrally on the back of the frame, eliminating the support frame (Japanese Patent Laid-Open No. 54-9271)
has already been proposed by the same applicant,
Since this was merely to fix the peripheral edge of the soundboard to the tip surface of the protruding body, it was necessary to form the shape of the tip surface along the crown of the soundboard.
It has the disadvantage of requiring high precision.

This invention was made in view of the above-mentioned points, and its first purpose is to directly fix the soundboard to the frame, create a predetermined crown, and eliminate the support frame, thereby simplifying the structure. The present invention also provides a piano frame structure that facilitates assembly work.

A second object of the present invention is to provide a piano frame structure in which the frame itself is installed on the floor via casters, and by supporting the weight of the piano with this frame, the strength of the entire piano can be increased. It provides:

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 2 is a schematic front view of the interior of the exterior body showing an embodiment of the piano frame structure according to the present invention applied to an upright piano, FIG. 3 is a side view of the same, and FIG. 4 is a schematic rear view. Figure 5 is Figure 2 B-B
It is a line enlarged sectional view. In addition, the same components as in FIG. 1 are indicated by the same reference numerals.
The explanation will be omitted. The frame 1 is integrally formed by casting, and the frame 1 is attached to the peripheral edge of the back side of the frame 1.
A rectangular frame-shaped soundboard holding portion 41 extending rearwardly is integrally provided in a protruding manner. This soundboard holding part 41 is used to fix and hold the peripheral part of the soundboard 28 in place of the conventional support frame body described above and to provide a predetermined crown. It is set to be somewhat smaller than the soundboard 28 before being attached. That is, FIG. 6 is a diagram showing the dimensional relationship between the soundboard holding part 41 and the soundboard 28 before crowning, and the distance L ₁ between the inner surfaces of the pair of left and right vertical pieces 41a and 41b that constitute the soundboard holding part 41 is shown in FIG. is set to be smaller than the width dimension L ₂ of the sound board 28 (L ₁ <L ₂ ), and similarly, the distance L 3 between the inner surfaces of the pair of upper and lower horizontal pieces 41c, 41d (see FIG. 5) is also set smaller than the width dimension L ₂ of the sound board 28. is set smaller than the height dimension.

Therefore _, when the soundboard 28 is fitted into the soundboard holder 41 from the back side of the frame ₁ as shown by the chain line in FIG. The dimensional difference between and L ₂ is reduced, thereby creating a predetermined crown in which the central portion gently bulges toward the surface. In this case, the peripheral edge of the back surface of the frame 1 surrounded by the soundboard holding portion 41 is formed into a curved surface 43 (or a slope similar to the crown) having approximately the same curvature as the crown of the peripheral edge of the soundboard 28, The frame 1 and the sound board 28 are more securely joined. And soundboard 2
As shown in FIG. 5, the peripheral edge of the ring 8 is firmly fixed to the curved surface 43 by a plurality of setscrews 45 screwed into a frame 44 fitted to the soundboard holder 41. The upper horizontal piece 41c constituting the soundboard holding section 41 is provided below the pin plate 12.

The frame 1 to which the soundboard 28 is attached has a pair of left and right connecting members 4, respectively, as shown in FIG.
6, and is firmly fixed to the inner surfaces of the left and right parent plates 26 and disposed within the exterior body 11. This exterior body 1
1 is the aforementioned pair of left and right parent plates 26, roof plates 47,
It is constructed of an upper front plate, a lower front plate, etc. (not shown), and is different from the conventional one in that it does not include the bottom plate 25 shown in FIG. And frame 1
A pair of left and right casters 48A, 48B are fixed to the lower surface of the
B supports the frame 1 by having its wheels in contact with the floor surface 50. In other words, the frame 1 is installed directly on the floor surface 50 via the pair of casters 48A, 48B, so that the exterior body 11
supporting the A pair of left and right end bases 5 are provided at the lower end of the exterior body 11 and extend forward, respectively.
1, there is a caster 52 on the lower surface of the tip as before.
A and 52B are provided, respectively. Therefore, the total weight of the piano 10 is the total weight of the four casters 4.
8A, 48B, 52A, 52B.

According to the piano frame structure having such a configuration, the soundboard 28 is directly attached to the frame 1, so the support frame, which was conventionally considered indispensable, can be removed, simplifying the structure and reducing weight. enable. Moreover, if the flat soundboard 28 is forcibly fitted to the soundboard holding part 41 provided on the back surface of the frame 1, the inner dimensions of the holding part 41 and the curved surface 4
3 allows a predetermined crown to be given to the soundboard 28, and the frame 1 functions not only as a strength member of the soundboard 28 but also as a strength member of the exterior body 11, and the entire weight of the piano is transferred to the frame 1. Since it can be concentrated, the strength of the piano can be increased and the structure can be made more robust.

Although the above embodiment describes a case in which the flat soundboard 28 is forcibly fitted into the soundboard holding portion 41 to form a predetermined crown, the present invention is not limited to this. Of course, a crown may be attached when the rod 30 is attached, and then the rod 30 may be fitted into the soundboard holding portion 41.

As explained above, the frame structure of the piano according to the present invention is such that a frame-shaped soundboard holder is integrally provided on the periphery of the back surface of the frame, and the periphery of the back surface of the frame surrounded by the holder is used as a soundboard. The soundboard is formed into a curved or sloped surface that is approximately equal to the crown of the soundboard, and the soundboard is fitted and fixed to the soundboard holder to hold the crown of the soundboard, so conventional support frames, machining, etc. are not required. The soundboard can be fixed and held more securely without having to do so. Furthermore, since a support frame or the like is not required, the soundboard assembly is simple and assembly work is easy, and the weight of the piano can be reduced.

In addition, the frame stands directly on the floor via casters and functions as a strength member that supports the entire weight of the piano, which has great effects such as reducing the required strength of the exterior body. be.

[Brief explanation of drawings]

Figures 1a, b, and c are partially cutaway side views showing the frame structure of a conventional upright piano, a front view of the frame, and a sectional view taken along line A-A. Figure 2 shows the frame structure of a piano according to the present invention. A schematic front view of the inside of the exterior body showing an example of application to an upright piano, Fig. 3 is a side view, Fig. 4 is a schematic rear view, and Fig. 5 is an enlarged cross section taken along the line B-B in Fig. 2. FIG. 6 is a diagram showing the dimensional relationship of the soundboard 40 before the soundboard holder is crowned. DESCRIPTION OF SYMBOLS 1... Frame, 11... Exterior body, 26... Main board, 28... Soundboard, 41... Soundboard holding part, 43...
...Curved surface, 48A, 48B... Caster.

Claims (1)

[Scope of Claims] 1. A frame-shaped soundboard holder whose inner dimension is smaller than the soundboard before crowning is integrally provided on the peripheral edge of the back side of the frame, and is surrounded by the soundboard holder of the frame. The periphery of the back surface of the soundboard is formed into a gently curved or sloped surface approximately equal to the crown of the soundboard, and the soundboard is fitted and fixed to the soundboard holder, and the crown of the soundboard is inserted into the inside of the soundboard holder. A frame structure for a piano, characterized in that the frame structure is set and held by the side surface and the curved surface or slope. 2. A frame-shaped soundboard holder is integrally provided on the peripheral edge of the back side of the frame, the soundboard is fitted and fixed to this soundboard holder to hold the crown of the soundboard, and the frame is attached to the exterior body of the piano. A frame structure for a piano, characterized in that casters are fixed to the inner surfaces of a pair of left and right parent plates constituting the frame, and casters are attached to the lower surface of the frame to support the frame in contact with the floor surface.