JPS59198495A - Support construction of grand piano - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention improves rigidity, reduces and prevents the effect of warping on the soundboard due to stringing of the frame, and maintains stable vibration transmission characteristics. Regarding the support structure of a grand piano.

[Prior art]

The support of a piano is required to have sufficient strength as a strength member that supports the weight of the frame and prevents the frame from collapsing due to stringing.At the same time, the soundboard can vibrate effectively in response to the string vibrations, allowing the sound to vary from bass to treble. It is required to be able to effectively radiate sound up to In particular, maintaining sufficient strength is extremely important not only for acoustic reasons, but also for setting and maintaining the string height at the correct position, simplifying tuning work, and maintaining a stable key touch over a long period of time. It is. Therefore, the support structure of a conventional grand piano is usually constructed as shown in FIGS. 1 and 2. That is, the pillars, which are generally designated by the reference numeral 1, include a curved pillar 2 in a deformed U shape whose front side (player side) is open, and a shelf board 10 with both ends joined to the inner surface of the curved pillar 2 near the open end. A central stile 3 disposed above, a plurality of straight columns 4 that are horizontally suspended between the inner surface of the inner stile 3 and the inner surface of the curved column 2 to reinforce the curved column 2;
The middle stile 5 and 1 are arranged in the back stile 3 and have both ends joined to the inner surface of the curved support 2, and the back stile 3. It is generally composed of a pivot 6 that integrally connects the straight support 4 and the middle frame 5, and a reinforcing plate 7, and a part of the periphery of the soundboard 8 is connected to the curved support 2 along with the end of the sound bar 11. A frame 9 is disposed on the upper end surface and the remaining peripheral edge is pasted to the middle stile 5 via a dowel 14 and a front attachment 12, and on which strings (not shown) are stretched. It is set up. A protrusion 9a called a tengu's nose is integrally provided on the lower surface of the frame 9 near the bass region, and a wedge 13 is interposed between the protrusion 9a and the main body 6. Therefore, the warpage caused by the stringing of the frame 9 is transmitted to the column 1 side via the projection 9a, the wedge 13, and the sleeve 6, and is suppressed by the rigidity of the column 1 as a whole.

By the way, Yagashi 3. Straight post 4. Middle stile 5 etc. are generally made of beech,
It is made of solid wood ranging from hard wood such as birch.
Hard wood is expensive and, moreover, it is difficult to obtain as resources become boiled. In addition, since the center frame 3 is formed in a straight line, the force F due to the warp of the frame 9
If this is applied at the six key points, it is easy to bend and high strength is required. Therefore, if the purpose is simply to increase strength, it may be possible to use metal materials as a substitute for wood, but metal material has significantly higher vibration transmission characteristics than wood, and vibration damping is slower. Therefore, it has the disadvantage of significantly impairing the sound quality of the piano as a natural musical instrument, and is therefore considered unsuitable.

[Summary of the invention]

This invention was made with emphasis on the key points mentioned above.
By forming the back stile from laminated plywood and curving it toward the open side of the curved support, the strength of the back stile is substantially increased, suppressing and preventing the frame from warping, and improving the vibration transmission characteristics of the soundboard. To provide a support structure for a grand piano that can be stably maintained.

〔Example〕

Hereinafter, this invention will be explained in detail based on the embodiment shown in the drawings. 1. FIG. 3 is a plan view showing an embodiment of a 414-piece column structure according to the invention, and FIG. 4 is a perspective view of the main parts. , in addition, the first
Components that are the same as those in the figures and No. 21 are designated by the same reference numerals, and their explanations are omitted. 30 is formed of straight plywood or parallel plywood made by laminating and bonding a plurality of veneers 31 with a thickness of about 3 to 4 mm, and has an appropriate curvature so that the central part in the longitudinal direction bulges toward the player. It is curved with a radius R. A similarly curved center stile 5 is fixed to the upper end of the outer surface of the center stile 30, and a curved batten 14 is fixed to the upper surface of the player side end of the center stile 5. A curved front attachment piece 12 is fixed to the upper surface of the player side end of the hitter 14. In addition, 34 is a side plate pasted on the outer surface of the curved support 2, and 35 is a fitting groove into which the end of the sound rod is fitted and fixed.

Thus, according to the pillar with such a configuration, the back stile 3
Since the strength of the frame can be substantially increased, the warping of the frame can be effectively suppressed and prevented. If the back stile 30 is curved toward the open side of the curved support 2, both ends will be restricted between the inner surfaces of the curved support 2 and will receive a reaction force, and the laminated plywood will not be subject to tensile stress due to its structure. It is strong against force and compressive force, so it is less likely to bend than conventional straight frames, and can withstand large forces, preventing frame deformation.Therefore, the stress caused by warping of the 7-frame frame is reduced. Back stile 30. Armor 5. Vibration is transmitted to the soundboard via the front mount 12 and the beater 14, and changes the internal stress of the soundboard itself. Can be maintained stably.

In addition, due to the curved formation of the back stile 30, the middle stile 5 and the stroke 1
When 2 is formed into a curved shape, the effective vibration area of the soundboard can be increased by the area shown by the diagonal lines in FIG. 3 compared to the case where these are formed in a straight line, and the volume and sound quality of the piano can be improved. Furthermore, when the back stile 30 is formed of laminated plywood, it has the advantage that it is cheaper and more easily available than solid wood, and is also easier to form into a predetermined shape. I'm so happy,
If the inner stile 30 is formed into a curve using well-known techniques such as boiling, steaming, microwave irradiation, etc., it is possible to arbitrarily curve the inner stile 30 with a radius of curvature up to a minimum of approximately R=10 crn.

Here, the radius of curvature R is given by the following formula: % (where E is Young's modulus, t is the thickness of the veneer 31, and σ is the compressive proportional limit stress). Board 31
Beech or birch wood is used as the material, and its thickness is 0.3 cm.
When m, R= 1.05O5X105(/cd) xo, 3(c
fn)/2X320 (K9./cJ) =49.2
cm. Therefore, it is fully possible to form the back stile 30 into a curve having such a radius of curvature.

By the way, although FIG. 4 shows an example in which the middle stile 5 is formed separately from the back stile 30 from solid wood and then joined to the back stile 30, the invention is not limited to this.
It is also possible to integrally form the middle stile 5 with the middle stile, and in that case, it is possible to eliminate the process of cutting the wood of the middle stile, joining process, etc., and the manufacturing process can be simplified.

FIGS. 5 and 6 are a plan view of a main part and an enlarged sectional view taken along the line Vl-VIM, showing another embodiment of the present invention.

In this embodiment, only the stile 30 is formed in a curved manner, and the middle stile 5, the front stile 12, and the stile 14 are formed in a straight line as in the conventional case. In this case, the middle stile 5 is fixed to the upper surface of the back stile 30 with wood screws, adhesive, or the like.

It will be obvious that even in such a configuration, warping of the frame can be prevented by the back stile 30 as in the above embodiment.

In addition, if the striking part 14 is formed in a curved manner and the joining surface ff+ with the peripheral edge of the soundboard is increased by reducing the edging process, it is possible to
It is also possible to abolish 2.

〔Effect of the invention〕

As described above, in the support structure of the grand piano according to the present invention, the center frame is formed into a VV structure using laminated plywood that is curved to resist the force caused by the warping of the frame.
It is possible to prevent the frame from warping due to string tension, it is possible to maintain the vibration transmission characteristics of the soundboard stably over a long period of time, it is possible to manufacture the back frame at low cost, and the materials are easy to obtain, but the effects are Very dog-like.

[Brief explanation of drawings]

1 and 2 are a perspective view and a cross-sectional view of the main part showing the support structure of a conventional grand piano, and FIGS. 3 and 4 are a plan view and an enlarged perspective view of the main part showing an example of the present invention. , Figures 5 and 6 show 2... curved support, 4...
...straight support, 5...middle stile, 6...necessary, 8...
・Soundboard, 9...Frame, 10...11'l&
, 30... Back stile. Patent applicant: Nippon Musical Instruments Co., Ltd. Agent Masaki Yamakawa (and one other person) Figure 3 Figure 4 I Figure 6

Claims (1)

[Claims] A back stile whose both ends are joined to the inner surface of the curved mirror column near the open end and which is disposed on the shelf board is made of laminated plywood. The pillar structure of G2Y Tobiano is characterized by