JP4484487B2 - Keyboard instrument keys - Google Patents

Description

  The present invention relates to a key for a piano or the like, and more particularly to an acoustic piano key to which a weight is attached in order to obtain a desired touch weight.

  A keyboard instrument, particularly an acoustic piano such as a grand piano, generally has a weight attached to the key in order to obtain a required touch weight (static load). The key includes a key body that extends in the front-rear direction and is swingably supported by a fulcrum at the center, and a weight attached to the key body. On the near side (performer side) of the fulcrum of the key body, a buried hole penetrating to the side is formed. The weight is generally made of lead and is formed into a columnar shape, and is attached to the key body by caulking from both sides by a caulking machine while being inserted into the embedding hole. As described above, lead is adopted as a weight material because it has a high specific gravity (about 11.3) among metals, and is flexible and ductile, so that it is easy to form and process and is inexpensive. It depends on things. However, lead is a hazardous substance and it is desirable to use other alternative materials.

  As a conventional piano key using a weight made of a material other than lead, for example, one disclosed in Patent Document 1 is known. In this piano key, the weight is composed of a composite material obtained by blending tungsten powder and synthetic resin. This tungsten powder is mainly composed of aggregates of particles (primary particles) of the minimum unit obtained by crushing agglomerates (secondary particles) generated in the manufacturing process of tungsten powder. The synthetic resin is composed of a thermoplastic resin or a thermoplastic elastomer. Thus, by using what consists of primary particles as tungsten powder, the filling property with respect to a synthetic resin improves, and it becomes possible to fill with a high ratio. Then, a high specific gravity weight is produced by injection molding or extrusion molding. The weight imparted with plasticity or elasticity by the synthetic resin is inserted into the buried hole of the key body and fixed to the key body by caulking or the like.

  However, in this piano key, in order to produce a weight composed of a composite material of tungsten powder and synthetic resin, a process of producing secondary particles by crushing relatively hard tungsten, A step of further crushing the particles to produce primary particles is required. For this reason, the manufacturing process becomes complicated, and dedicated equipment for that purpose is required, and the manufacturing cost increases accordingly.

  Moreover, what was disclosed by patent document 2 is known as another conventional weight which uses materials other than lead. As shown in FIG. 5, the weight 51 includes a weight attachment member 52 and a weight main body 53 fitted in the weight attachment member 52, and is formed in a columnar shape as a whole. The weight attachment member 52 is a cylindrical member having an insertion hole 52a having a circular cross section, and is made of an elastic material such as rubber. The weight main body 53 has a cylindrical shape that can be fitted into the insertion hole 52a of the weight attachment member 52, and is formed of a composite material that is a blend of powdered tungsten and synthetic resin. The weight 51 having the above structure is attached to the key body by inserting the weight body 53 into the insertion hole 52a of the weight attachment member 52 and inserting the weight body 53 into a buried hole (both not shown). . As described above, the weight main body 53 having a relatively high hardness can be attached to the key main body via the weight attachment member 52.

  However, since the weight 51 also includes a step of powdering tungsten having relatively high hardness and a step of blending powdered tungsten with a synthetic resin, it takes time to produce the weight main body 53. Further, since the weight attaching member 52 made of an elastic material such as rubber is inserted into the embedding hole of the key body, it cannot be caulked. As described above, the manufacturing process is complicated and the existing caulking machine equipment cannot be used, resulting in an increase in manufacturing cost.

  The present invention has been made in order to solve the above-mentioned problems. The weight of the existing caulking machine is not specially treated while using an alternative material that is difficult to caulk instead of lead. An object of the present invention is to provide a key of a keyboard instrument that can be easily attached to a key body using equipment, thereby reducing manufacturing costs.

Japanese Patent Laid-Open No. 2002-265793 (pages 2 and 3, FIG. 1) Japanese Patent Laid-Open No. 2001-147585 (page 3, FIG. 2)

To achieve this object, the key of the keyboard instrument according to claim 1 is composed of a swingable key body having a buried hole, a weight inserted into the buried hole, and a material having ductility other than lead. It is inserted into is, buried holes, as well as engage in weight, is crushed by caulking, by being pressed against the inner surface of the burying hole, comprising a weight fixing member for fixing the weight to the key body, a weight fixing member It is composed of two weight fixing members. By crimping the two weight fixing members on both sides of the weight, the two crushed weight fixing members are crimped to the inner surface of the buried hole, and the weight is The weight is fixed to the key body by pinching .

  According to the key of this keyboard instrument, a weight fixing member for fixing the weight to the key body is provided, and the weight fixing member is made of a material other than ductile lead, for example, tin or aluminum. . The weight fixing member is inserted into the embedding hole of the key body together with the weight, and is caulked while being engaged with the weight. As a result, the weight fixing member that has been crushed is pressure-bonded to the inner surface of the embedding hole, whereby the weight is fixed to the key body while being locked to the weight fixing member. As a result, a material having a high specific gravity that is difficult to be caulked, such as a single weight of tungsten (specific gravity: about 19.1) or bismuth (specific gravity: about 11.3), is inserted into the key through the weight fixing member having ductility. It can be fixed to the body, thereby giving the key the required touch weight. Therefore, unlike the prior art, a process such as pulverization of a material with a high specific gravity is not required to produce a weight. Further, since the weight is fixed to the key body by caulking, the existing caulking machine can be used as it is. As described above, the weight can be easily attached using the existing caulking machine equipment, using the weight made of a single high specific gravity material without any special treatment on the weight. Manufacturing cost can be reduced.

Also, by caulking in a state where two weight fixing members are arranged on both sides of the weight, each of the crushed weight fixing members is crimped to the inner surface of the embedded hole, and the weight is clamped so that the weight is the key body. Fixed to. Thus, in this invention, since a weight is clamped by the two weight fixing members of the both sides, a weight can be fixed more firmly than the case of Claim 2. Further, the weight and the weight fixing member can be simply configured. For example, the weight and the weight fixing member can be configured by only the columnar weight and the two disk-shaped weight fixing members, thereby reducing the manufacturing cost.

According to a second aspect of the present invention, in the key of the keyboard instrument according to the first aspect, a concave portion is formed at one center of the weight both ends and the weight fixing member, and a convex portion engaging with the concave portion is formed at the other center. A portion is provided.

  According to this configuration, the weight fixing member is caulked in a state in which the convex portion provided at the other center is engaged with the concave portion formed at one end of the weight fixing member and the weight fixing member. Therefore, centering of the weight fixing member with respect to the weight can be easily performed with high accuracy, and thereby the pressure fixing of the weight fixing member to the embedded hole by caulking can be performed with good balance and stability. In addition, since the weight is locked by the weight fixing member due to the engagement between the concave portion and the convex portion, rattling of the weight with respect to the key body can be prevented. Deterioration can be prevented.

It is a perspective view which shows the key of the grand piano by 1st Embodiment of this invention. FIG. 2 is a schematic cross-sectional view of the key of FIG. 1 before (a) caulking and after (b) caulking. It is a schematic cross-sectional view of the key according to the second embodiment before (a) caulking and after (b) caulking. It is a schematic cross-sectional view of the key according to the modification of the second embodiment before (a) caulking and after (b) caulking. It is a perspective view which shows the weight of the key of the conventional grand piano.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a key (white key) of a grand piano according to the first embodiment of the present invention. As shown in the figure, the key 1 includes a key body 2, a white key cover 3 attached to the front portion of the key body 2, a weight 4, a weight fixing member 7, and the like.

  The key body 2 is made of a relatively light, sticky, elastic wood material such as spruce, has a rectangular cross section, and extends in the front-rear direction. The white key cover 3 is formed in an L shape using a synthetic resin such as acrylic, or ivory, and is bonded to the upper half of the upper surface and the front surface of the key body 2 so as to cover them. An intermediate seat plate 5a is bonded to the central portion of the upper surface of the key body 2, and a balance pin hole 5 is formed so as to penetrate these vertically. The balance pin hole 5 engages with a standing balance pin (not shown), so that the key body 2 is swingably supported by the balance pin. A front pin hole 6 is formed in the front end portion of the lower surface of the key body 2, and a front pin (not shown) that is erected engages to prevent the key 1 from swinging left and right.

  Further, a capstan screw 8 is provided behind the balance pin hole 5 on the upper surface of the key body 2 via a capstan seat plate 8a, and an action (not shown) is provided on the capstan screw 8. ) Is placed. With the above configuration, when the front portion of the key 1 is depressed, the key 1 operates by being pushed up by the capstan screw 8 as the key 1 swings around the balance pin. The touch weight of the key 1 is determined by the balance of the moment around the balance pin due to the action and the weight of the key 1.

  The key body 2 is formed with a buried hole 11 for fixing the weight 4. The buried hole 11 penetrates laterally at a predetermined position on the near side of the balance pin hole 5, is circular in cross section, and has a predetermined diameter.

  The weight 4 has a cylindrical shape having an insertion hole 12 having a circular cross section, and is made of a material having a high specific gravity other than lead, for example, a single tungsten (specific gravity: about 19.1). The diameter of the weight 4 is substantially the same as the diameter of the buried hole 11. As the weight 4, a plurality of types of weights 4 having different lengths are prepared. Among these, FIG. 2 shows the longest weight 4, which is slightly shorter than the length of the embedded hole 11, that is, the width of the key body 2.

  The weight fixing member 7 is made of a material having ductility other than lead, for example, tin. As shown in FIG. 1, the weight fixing member 7 includes a disk-shaped head 13 and a shaft portion 14 having a circular cross section extending from the center thereof. The rivet shape is formed. The head 13 has a predetermined thickness and substantially the same diameter as the diameter of the weight 4. The length of the shaft portion 14 is longer than that of the weight 4, and the diameter is substantially the same as the diameter of the insertion hole 12 of the weight 4.

  The weight 4 having the above configuration is fixed to the key body 2 using the weight fixing member 7 as follows. As shown in FIG. 2A, first, the shaft portion 14 of the weight fixing member 7 is inserted into the insertion hole 12 of the weight 4 so that the head portion 13 abuts on the weight 4 and the tip portion 15 of the shaft portion 14 is moved. A state of protruding from the insertion hole 12 is set. Next, in this state, the weight 4 is inserted into the embedding hole 11 of the key body 2 together with the weight fixing member 7, and the weight fixing member 7 is pressed from both sides of the embedding hole 11 with the caulking rods P and P of the caulking machine. Caulking by doing. As a result, as shown in FIG. 2B, the head 13 of the weight fixing member 7 and the tip 15 of the shaft portion 14 are both crushed. The weight 4 is sandwiched between the end portion 15 of the crushed shaft portion 14 and biting into the inner surface of the shaft portion 14. In this way, the weight 4 is fixed to the key body 2 through the weight fixing member 7 that is crimped to the embedded hole 11 by caulking.

  As described above, according to the key 1 of the grand piano of this embodiment, the weight fixing member 7 made of ductile tin is inserted into the embedding hole 11 of the key body 2 together with the weight 4 and caulked. Thus, the weight 4 is fixed to the key body 2 via the weight fixing member 7 that is pressure-bonded to the inner surface of the embedded hole 11. Therefore, a single tungsten weight 4 having a high hardness that is difficult to be caulked can be fixed to the key body 2. Further, since tungsten having a very high specific gravity is employed as the material of the weight 4, the weight of the weight 4 can be sufficiently secured. Furthermore, since a plurality of types of weights 4 having different lengths are prepared as the weights 4, a desired touch weight is applied to the key 1 by selecting a weight having a desired weight from the weights 4. Can be added.

  Further, unlike the prior art, a process of making tungsten with relatively high hardness into a powder form or blending with a synthetic resin becomes unnecessary. Furthermore, since the weight 4 is fixed to the key body 2 by caulking, the existing caulking machine equipment can be used. Further, since the weight 4 can be fixed to the key body 2 with one weight fixing member 7, the number of parts and the number of mounting steps can be reduced. As a result, the manufacturing cost can be reduced.

  Further, since the shaft portion 14 of the weight fixing member 7 is entirely inserted into the insertion hole 12 of the weight 4, the head portion 13 of the weight fixing member 7 is radial with respect to the weight 4 during caulking. Will not slip or tilt. Therefore, pressure bonding of the weight fixing member 7 to the buried hole 11 by caulking can be stably performed with good balance.

  FIG. 3 shows a key 21 of a keyboard instrument according to the second embodiment of the present invention. In the figure, the same reference numerals are used to denote the same components as those in the first embodiment. The key 21 of the keyboard instrument of the present embodiment is different in the shape of the weight 22 and the number of weight fixing members 23 from the first embodiment.

  As shown in the figure, the weight 22 has a cylindrical shape having a predetermined diameter and length, and is made of a single piece of tungsten as in the first embodiment. On the other hand, the weight fixing member is composed of two weight fixing members 23 and 23. Each weight fixing member 23 is a disk-shaped member having a predetermined thickness, and its diameter is substantially equal to the diameter of the embedded hole 11.

  With the above configuration, the weight 22 is fixed to the key body 2 using the two weight fixing members 23 and 23 as follows. First, the weights 22 are inserted into the embedding holes 11 of the key body 2, and the weight fixing members 23 are arranged on both sides of the weight 22 (the state shown in FIG. 5A). Next, in this state, the weight fixing members 23 and 23 are caulked from both sides of the embedded hole 11. As a result, the weight fixing members 23, 23 are crushed and their outer peripheral surfaces are crimped to the inner surface of the embedded hole 11, and the weight 22 is inserted between the weight fixing members 23, 23, as shown in FIG. The weight 22 is fixed to the key body 2 by clamping.

  As described above, also in the second embodiment, similarly to the first embodiment, the tungsten weight 22 can be fixed to the key body 2 by caulking the weight fixing members 23 and 23. Thus, in the second embodiment, the weight 22 is sandwiched between the two weight fixing members 23, 23 on both sides thereof, so that the weight 22 can be more firmly fixed to the key body 2 than in the first embodiment. Further, unlike the first embodiment, the weight 22 may be formed in a simple columnar shape without the insertion hole 12, and the weight fixing member 23 may be formed in a simple disk shape, thereby reducing the manufacturing cost. can do.

  FIG. 4 shows a key 31 of a keyboard instrument according to a modification of the second embodiment. As shown in the figure, the weight 32 of the key 31 is formed by forming recesses 33 and 33 at the centers of both end faces of a columnar weight similar to the second embodiment, and each weight fixing member 34. Are provided with a convex portion 35 that engages with the concave portion 33 of the weight 32 at the center of the weight fixing member similar to the second embodiment.

  With the above configuration, the weight 32 is inserted into the embedding hole 11 of the key body 2, and the convex portions 35 of the weight fixing member 34 are engaged with the concave portions 33 of the weight 32, as in the second embodiment. Further, the weight 32 is fixed to the key body 2 by caulking the weight fixing members 34, 34.

  As described above, the weight fixing members 34 and 34 are caulked in a state where the convex portions 35 of the weight fixing member 34 are engaged with the respective concave portions 33 on both end surfaces of the weight 32. Accordingly, each weight fixing member 34 can be centered accurately and easily with respect to the weight 32, whereby the weight fixing member 34 can be crimped to the embedded hole 11 by caulking in a balanced and stable manner. it can. Further, since the weight 32 is locked to the weight fixing members 34, 34 by the engagement between the concave portion 33 and the convex portion 35, the weight 32 can be prevented from rattling with respect to the key body 2, and as a result, when the key is depressed. Generation of noise and deterioration of touch feeling can be prevented.

  In addition, this invention can be implemented in various aspects, without being limited to the described embodiment. For example, in the modification of FIG. 4, the recesses 33 are formed on both end surfaces of the weight 32, but instead of this, a penetrating hole such as the insertion hole 12 of the first embodiment may be formed. . Moreover, although the recessed part 33 is provided in the weight 32 side and the convex part 35 is provided in the weight fixing member 34 side, these may be arrange | positioned conversely. In the embodiment, tin is adopted as the material of the weight fixing member. However, other suitable material having ductility other than lead, for example, aluminum may be used. In the present embodiment, the number of the embedding holes 11 formed in the key body 2 is one, but it is needless to say that the number may be two or more. Further, although tungsten is adopted as the weight material, a material having a high specific gravity other than lead, such as bismuth, may be used.

  Furthermore, although the embodiment is an example of a key for a grand piano, the present invention can be widely applied to all keys to which weights are attached, such as keys for upright pianos, electronic pianos, and keyboard instrument toys. . In addition, it is possible to appropriately change the detailed configuration within the scope of the gist of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Key 2 Key main body 4 Weight 7 Weight fixing member 11 Buried hole 12 Insertion hole 13 Head 14 Shaft part 15 Tip part 21 Key 22 Weight 23 Weight fixing member 31 Key 32 Weight 33 Recessed part 34 Weight fixing member 35 Protruding part

Claims (2)

A swingable key body with a buried hole,
A weight inserted into the buried hole;
It is made of a material having ductility other than lead, inserted into the embedded hole, engaged with the weight, crushed by caulking, and crimped to the inner surface of the embedded hole, whereby the weight is attached to the key body. A weight fixing member for fixing ,
The weight fixing member is composed of two weight fixing members,
By caulking the two weight fixing members in a state where they are arranged on both sides of the weight, the two weight fixing members that are crushed are pressed against the inner surface of the embedded hole, and the weight is sandwiched between the two weight fixing members. A key of a keyboard instrument , wherein the weight is fixed to the key body . The concave part is formed in one center of the both end surfaces of the weight and the weight fixing member, and a convex part engaging with the concave part is provided in the other center. Key of the keyboard instrument.

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