JPH04236806A - Leg beam of grand piano - Google Patents

Abstract

PURPOSE:To obtain a leg beam capable of being subjected to material replacement without increasing a material volume for the leg beam of a grand piano. CONSTITUTION:Reinforcing dowels 20A and 20B are buried in the leg beam 11 of a grand piano. The reinforcing dowels 20A and 20B are buried between the parts 13A and 13B for fixing the leg beam 11 to a piano body 12. These reinforcing dowels 20a and 20B are arranged in extension along the direction crossing the longitudinal direction of the leg beam 11 at nearly right angles. The strength of the leg beam 11 is improved b these reinforcing dowels 20A and 20B.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to the leg girders of grand pianos, and by embedding reinforcing members in the leg girders to improve the strength of the leg girders, it is possible to substitute materials without increasing the amount of wood used. This is what I did.

0002

2. Description of the Related Art Generally, in the structure of a grand piano, problems in terms of strength arise in the leg girder, which is the connecting part between the leg and the piano body. For example, if an impact force of a certain value or more acts on the tip of the pedestal, the pedestal will break, especially in its width direction. Therefore, in this grand piano, it is necessary to maintain the strength of the leg girder at a constant value.

[0003] Conventionally, the leg girder of a grand piano is as shown in Figs.
The structure was as shown in FIG.

That is, on the lower surface of the main body 101 of the grand piano, a substantially trapezoidal leg girder 102 is connected to two bolts 103.
It is fixed by A and 103B. That is, the leg girder 102 has a wide upper portion, and both longitudinal ends thereof are joined to the main body 101 by bolts 103A and 103B. In addition, the lower part of the leg girder 102 is narrow,
An attachment hole 104 is formed in the center (FIG. 12), and the upper end of the pillar 105 is fitted into and fixed to this attachment hole 104. Note that casters 106 are provided at the lower end of the pillar 105.
is installed.

[0005] Therefore, in order to increase the strength of the leg girder 102 having a structure made of a single material, for example, the volume of the material must be increased or a high-grade material with high splitting strength must be used.

[0006]

[Problems to be Solved by the Invention] However, in the case of the leg girders of such conventional grand pianos, the material used was limited because the volume of the material was increased and high-quality materials were used.

Therefore, the present invention provides a leg girder for a grand piano that can use various materials such as southern wood, reduce the volume of the wood, and improve the versatility of the wood used as a whole. Its purpose is to provide.

[0008]

[Means for Solving the Problems] The present invention provides a leg girder for a grand piano that is fixed to the upper end of the leg column of the grand piano and is fixed to the main body of the grand piano at a plurality of fixing parts. This is a leg girder for a grand piano having a reinforcing member embedded so as to extend along a direction substantially orthogonal to the longitudinal direction of the leg girder at a position between the two parts.

[0009]

[Function] In the present invention, reinforcing members are embedded in the leg girders of the grand piano, so that the strength thereof is increased. Therefore, a certain level of strength can be maintained without increasing the volume of the material.
Also, other types of wood can be used instead of high-quality wood.

0010

[Embodiment] Hereinafter, an embodiment of a leg girder for a grand piano according to the present invention will be described.

[0011] First embodiment

1 to 3 show a first embodiment of the present invention. In these figures, reference numeral 11 indicates a leg girder, and this leg girder 11 is fixed to the lower surface of a piano body 12 of a grand piano. The leg girder 11 is formed into a substantially trapezoidal shape with a long upper portion and a shorter lower portion. Further, this leg girder 11 has a constant width.

Therefore, the leg girder 11 is formed thinner at both ends 11A, 11B in the longitudinal direction than at the center 11C.
It is fixed to the lower surface of the piano body 12 by leg mounting bolts 13A and 13B.

Specifically, a through hole 14 is formed in each of the end portions 11A and 11B, and leg attaching bolts 13A and 13B are inserted through the through holes 14 and screwed into the leg attaching nut 15, respectively. 16 is a leg mounting washer. Note that the leg attachment nuts 15 are fixed to the piano body shelf board 12.

[0015] Also, the thick center portion 1 of this leg girder 11
A fitting hole 17 is formed in 1C and penetrates in the vertical direction, and the upper end of the pillar 18 is fitted into this fitting hole 17 and fixed. Note that casters 1 are attached to the lower end of the pillar 18.
9 is attached.

Here, each of the through holes 1 in the leg girder 11
4 drilling position, that is, leg mounting bolts 13A, 13B
Reinforcing dowels 20A and 20B are buried inside the fixing position and closer to the center portion 11C, respectively. These reinforcing dowels 20A and 20B are buried in a plane perpendicular to the longitudinal direction so that both ends thereof face the lower and upper surfaces of the leg girder 11, respectively, and extend diagonally as shown in FIG. . Each of the reinforcing dowels 20A and 20B is a round bar, and is embedded and fixed in the leg girder 11 by fitting wood, metal, synthetic resin, etc., or by gluing.

Note that these reinforcing dowels 20A and 20B are used as reinforcing members for the leg girder 11, and instead of the round rods, wood screws may be screwed and embedded inside the leg girder 11. At this time, the leg girder 11 is not limited to high-quality wood, but may also be made of southern wood with low hardness.

According to the above structure, when an impact force is applied from the lower end of the pedestal 18, for example, the caster 19, a predetermined bending moment, shearing force, etc. will be applied to the pedestal 11. At this time, reinforcing dowels 20A and 20B are embedded in the leg girder 11 in areas where stress concentration due to these forces occurs. The strength of the leg girder 11 as a whole is increased by the reinforcing dowels 20A and 20B. Therefore, the reinforcing dowels 20A and 20B can provide the leg girder 11 with strength equal to or greater than that obtained when the leg girder 11 is made of high-quality material. Therefore, sufficient strength can be exhibited even against the above-mentioned acting force.

Second embodiment

In this embodiment, as shown in FIGS. 4 to 6,
Two types of reinforcing dowels 41 and 42 are embedded in the leg girder 44 between the leg attachment bolts 43A and 43B as reinforcing members. The reinforcing dowel 41 has a plane perpendicular to the longitudinal direction of the leg girder 44 (
The reinforcing dowels 42 are buried extending horizontally in a plane (horizontal to the floor), and the reinforcing dowels 42 are buried extending vertically in the same plane.

[0021] These reinforcing dowels 41 and 42 can increase the strength of the leg girder 44 as in the above embodiment. Note that the other configurations and operations are the same as those of the above embodiment. Note that wood screws may be buried in place of the reinforcing dowels 41 and 42.

Third embodiment

As shown in FIGS. 7 to 9, in this embodiment, dovetail-shaped reinforcing plates 71A and 71B are embedded in the upper surface of the leg girder 72. The reinforcing plates 71A and 71B are buried extending in a horizontal direction perpendicular to the longitudinal direction at a position between the fixing portions at both ends (threaded portions of the leg mounting bolts 73A and 73B) and the insertion holes 75 of the footnote 74, respectively. ing. Note that the other configurations and operations are the same as those of each of the above embodiments.

[0024]

[Effects of the Invention] As explained above, according to the present invention, the strength of the leg girder can be increased without increasing the volume. Therefore, southern timber or the like can be used as the leg girders. Furthermore, when high-quality materials are used for the leg girders, the volume of the leg girders can be reduced, and the overall versatility of the wood used can be improved.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view of a leg girder of a grand piano according to a first embodiment of the present invention.

FIG. 2 is a side sectional view showing the leg girder of the grand piano according to the first embodiment of the present invention.

FIG. 3 is a plan view showing the leg girder of the grand piano according to the first embodiment of the present invention.

FIG. 4 is a partially cutaway front view of a leg girder of a grand piano according to a second embodiment of the present invention.

FIG. 5 is a side sectional view showing a leg girder of a grand piano according to a second embodiment of the present invention.

FIG. 6 is a plan view showing a leg girder of a grand piano according to a second embodiment of the present invention.

FIG. 7 is a partially cutaway front view of a leg girder of a grand piano according to a third embodiment of the present invention.

FIG. 8 is a side sectional view showing a leg girder of a grand piano according to a third embodiment of the present invention.

FIG. 9 is a plan view showing a leg girder of a grand piano according to a third embodiment of the present invention.

FIG. 10 is a partially cutaway front view of a leg girder of a conventional grand piano.

FIG. 11 is a side sectional view showing a leg girder of a conventional grand piano.

FIG. 12 is a plan view showing a leg girder of a conventional grand piano.

[Explanation of symbols]

11 Leg girder, 11A, 11B Both ends of leg girder (
Fixed part), 12 Piano body, 20A, 20
B Reinforcement dowel (reinforcement member)

Claims (1)

[Claims] Claim 1: A leg girder for a grand piano that is fixed to the upper end of the leg of the grand piano and fixed to the main body of the grand piano at a plurality of fixing parts, the leg girder being fixed at a position between these fixing parts. A leg girder for a grand piano, characterized by having a reinforcing member buried so as to extend along a direction substantially orthogonal to the longitudinal direction of the girder.