JP5336215B2 - Hammer shank and manufacturing method thereof - Google Patents

Description

  The present invention relates to a hammer shank incorporated in a piano and a manufacturing method thereof.

  As shown in FIG. 5, the piano hammer shank 100 is formed in a substantially rod shape, and one end side in the longitudinal direction is formed thicker than the other portion (the shank rod portion 101). And the arm part 103 divided into the forked part is formed in the edge part of this thickly formed part (flange part 102). In addition, the hammer shank 100 has a hammer head attached to the end portion in the longitudinal direction opposite to the side on which the arm portion 103 is formed.

  The hammer shank 100 has an arm portion 103 sandwiching an arrangement portion 201 formed at the longitudinal end of the shank flange 200 fixed to the piano body, and passes the pin 104 through the arm portion 103 and the arrangement portion 201. Thus, it is fixed so as to be rotatable with respect to the shank flange 200.

  In the piano, when the key is pressed, the above-described hammer shank 100 is lifted through an action (not shown). At this time, the hammer shank 100 is lifted while rotating with respect to the shank flange 200. And by this rotation, the hammer head is moved upward, and the piano wire above the hammer head is struck, and the struck piano wire resonates the soundboard to produce sound. (Patent Document 1).

JP 2008-242427 A

  By the way, many members of the piano are made of wood, and the above-described hammer shank 100 is often made of wood.

  However, the wooden hammer shank 100 has a large friction between the arm portion 103 and the arrangement portion 201 of the shank flange 200 when the arm portion 103 absorbs moisture and loses its shape. May end up.

  When the friction is increased in this way, there is a problem that the response time from the key pressing to the string hitting by the hammer head hitting the piano wire is delayed.

  For this reason, it has been considered that the hammer shank 100 is not made of wood but is made of a synthetic resin that is less likely to lose its shape than wood.

  However, if the hammer shank 100 is made of synthetic resin, the hammer shank 100 becomes heavier than when the hammer shank 100 is made of wood, so that there is a problem that the response time from key pressing to string hitting is delayed.

  An object of this invention is to provide the hammer shank which is light and does not lose shape in view of the said point.

The hammer shank according to claim 1, which is an invention made to solve the above-mentioned problem, is a wooden hammer shank for a piano in which a frenzy part having an arm part divided into two parts is formed at one end in the longitudinal direction. The synthetic resin is impregnated only in the frenzy part.

  This wooden hammer shank is impregnated with synthetic resin in the frenzy part, which is the connecting part with the shank frenzy, and prevents the frenzy part from losing its shape by absorbing moisture and expanding and deforming. be able to. Therefore, if this hammer shank is used, the friction between the shank and the flange will not increase due to the deformation.

  In addition, the hammer shank is impregnated with synthetic resin, but most of the volume is wood, so that it is much lighter than when the entire hammer shank is made of synthetic resin. Moreover, since this hammer shank is impregnated only with a portion of the synthetic resin (the frenzy part), the increase in weight relative to the wooden hammer shank that is not impregnated with resin is the case where the entire hammer shank is made of synthetic resin. Compared to

  Therefore, if the hammer shank according to the present invention is used, it is light and does not lose its shape, thereby preventing a delay in response from key pressing to string striking due to friction between the hammer shank and the shank flange and an increase in the weight of the hammer shank. be able to.

  The hammer shank may be formed in a rod shape having substantially the same diameter. However, as in the hammer shank described in claim 2, a flange portion is formed at one end in the longitudinal direction of the shank rod portion. May be formed thicker than the shank bar in the direction in which the arms are arranged.

  Next, as described in claim 3, the hammer shank described above is preferably manufactured by the following manufacturing method.

  The manufacturing method includes a step of preparing a wooden hammer shank material in which a bifurcated arm portion is formed along one side and a plurality of hammer shanks can be cut out by cutting along a direction orthogonal to the one side. And a sealing step for capping a portion of the hammer shank material excluding the portion corresponding to the frenzy portion that forms the frenzy portion when cut out, an impregnation step for impregnating the frenzy portion corresponding portion with a synthetic resin, and coating It is preferable to have a stitch removal step for removing the portion seal and a cutting step for cutting the hammer shank material to cut out a plurality of hammer shanks.

  According to this manufacturing method, a plurality of the hammer shanks described above can be manufactured with a greatly simplified man-hour.

  In addition, as described in claim 4, it is preferable that the sealer agent is applied to the coat portion in the sealing step, and the sealer agent applied to the coat portion is removed by shaving in the seal removal step. If it does in this way, it can seal reliably and can impregnate only a frenzy part with a synthetic resin.

It is a side view of action 2 and hammer 3 of this embodiment. It is a perspective view of the hammer 3 of this embodiment. It is a disassembled perspective view which shows the structure for attaching the hammer shank 31 of this embodiment to the shank flange 30 so that rocking | fluctuation is possible. The perspective view of the hammer shank material 5 of the present embodiment is used to sequentially show a part of the manufacturing process of the hammer shank 31, wherein (a) is a preparation process, (b) is a closing process, and (c) is an impregnation process. , (D) is an explanatory diagram for explaining a step removal process, and (e) is an explanatory diagram for explaining a cutting process. It is a disassembled perspective view which shows the structure for attaching the conventional hammer shank to a shank flange so that rocking | fluctuation is possible.

  Next, an embodiment to which the present invention is applied will be described with reference to the drawings.

[Overall structure]
The overall concept of the portion of the grand piano that strikes the piano line of each scale by the player's key pressing operation will be described.

  Here, FIG. 1 is a side view of the action 2 and the hammer 3.

  The grand piano has a keyboard composed of a large number of keys arranged in the left-right direction when viewed from the performer. Each key of this keyboard extends along the player's front-rear direction, and is supported so as to be swingable around a balance pin that is erected on the shelf on the shelf at the approximate center in the longitudinal direction. .

  As shown in FIG. 1, the action 2 is installed above a portion in front of the rocking center of the key 1, and the hammer 3 is installed further above the action 2.

  Each of the action 2 and the hammer 3 is configured to be swingable. When the rear side of the key 1 is pressed, the front side is lifted to lift the action 2, and the hammer 3 is further lifted to jump upward. It has a structure for striking a string S composed of a piano wire suspended upward.

  Hereinafter, the action 2 and the hammer 3 thus configured will be described in detail.

  In the following description, the terms left and right direction and front and rear direction may be used. These are the left and right directions as viewed from the performer of the grand piano (the direction perpendicular to the plane of FIG. 1: the left direction in FIG. 1). And the front-rear direction of the performer (left-right direction of the paper surface of FIG. 1; indicated by arrows pointing in both the left-right direction in FIG. 1).

[Action 2]
The action 2 mainly includes a whippen 20, a jack 21 and a repetition lever 22.

  The whippen 20 extends along the front-rear direction, and the front end is rotatably supported by the whippen frenzy 20a.

  The whippen frenzy 20a is screwed to the whippen rail 11 which extends along the vertical direction and is passed to a plurality of brackets 10 (only one is shown in FIG. 1) arranged at intervals in the horizontal direction. Has been.

  The whippen frenzy 20a is provided with two left and right arms 20b (only the left one is shown in FIG. 1) at the upper end.

  The wippen 20 has its front end portion inserted between both arm portions 20b, and the center pin 20c is passed horizontally through the front end portion and both arm portions 20b of the wippen 20 so that the wippen frenzy centering on the center pin 20c. It is supported to be swingable with respect to 20a.

  Further, the wippen 20 includes a heel portion 20d that protrudes downward at a central portion in the front-rear direction. The wippen 20 is placed on the key 1 via the heel portion 20d and a capstan screw 1a provided at the rear portion of the key 1.

  The whippen 20 has a jack 21 connected to the rear end.

  The jack 21 has an L-shaped side surface by a hammer push-up portion 21a extending in the vertical direction and a regulating button contact portion 21b extending forward at a substantially right angle from the lower end portion thereof.

  A bifurcated left and right arm portion 20f (only the left one is shown in FIG. 1) is provided at the rear end portion of the wippen 20, and a corner portion of the jack 21 is disposed between the both arm portions 20f. A center pin 21 c is passed horizontally through the corners of both arms 20 f and the jack 21. As a result, the jack 21 is rotatably supported by the rear end portion of the wippen 20 around the center pin 21c.

  Further, the upper end portion of the hammer push-up portion 21a engages with a jack guide hole 22b, which will be described later, of the repetition lever 22, and has a slight gap with a shank roller 36, which will be described later, placed on the repetition lever 22. Opposite.

  Further, the jack 21 is urged in the return direction (counterclockwise in FIG. 1) by a repetition spring 24 described later.

  The repetition lever 22 is supported by a lever flange portion 20e that extends obliquely backward and upward in the front-rear direction and protrudes upward from the center portion of the wippen 20 in the front-rear direction.

  At the upper end portion of the lever flange portion 20e, two left and right arm portions 20g (only the left one is shown in FIG. 1) are provided.

  A central portion of the repetition lever 22 is disposed between the both arms 20g, and a center pin 22a is horizontally passed through the both arms 20g and the repetition lever 22.

  Thereby, the repetition lever 22 is rotatably supported by the upper end part of the lever flange part 20e centering | focusing on the center pin 22a.

  The repetition lever 22 is urged in the return direction (counterclockwise in FIG. 1) by a repetition spring 24 attached to the lever flange portion 20e.

  Further, the repetition lever 22 has a jack guide hole 22b penetrating in the vertical direction at the rear portion thereof, and the hammer 3 is placed via a shank roller 36 that contacts the vicinity of the jack guide hole 22b on the upper surface. .

[Hammer 3]
The hammer 3 mainly includes a shank flange 30, a hammer shank 31, and a hammer head 32.

  Here, FIG. 2 is a perspective view of the hammer 3, and FIG. 3 is an exploded perspective view showing a structure for swingably attaching the hammer shank 31 to the shank flange 30.

  The shank flange 30 is made of a synthetic resin, and is screwed to the upper surface of the hammer shank rail 12 passed between the plurality of brackets 10 as shown in FIG. A regulating button 4 is attached below the hammer shank rail 12.

  The shank flange 30 extends in the front-rear direction, and has a rectangular cross section as shown in FIG.

  The front end portion of the shank flange 30 is provided with an arrangement portion 30a that has a width slightly smaller than a dimension between both arm portions 31c (to be described later) of the hammer shank 31 and protrudes forward and can be disposed between both arm portions 31c. Yes.

  As shown in FIG. 3, a pin mounting hole 30b penetrating in the left-right direction is formed in the arrangement portion 30a. Moreover, the button 30c is provided in the lower surface of this arrangement | positioning part 30a (refer FIG. 1).

  The center pin 31d passes through the bearing 31e and the pin mounting hole 30b between them with the arrangement portion 30a arranged between the both arm portions 31c with a slight gap between them. Has been.

  The center portion of the center pin 31d is fixed to the pin mounting hole 30b, and both end portions are rotatable with respect to the bearing 31e.

  Thereby, the hammer 3 is rotatably supported by the shank flange 30 via the center pin 31d integrated with the shank flange 30.

  The hammer shank 31 is made of an elongated rod-shaped wood, and the rear end of the hammer shank 31 is thicker than the other portions in the horizontal direction of the arm portions 31c described later. The thick part is hereinafter referred to as a frenzy part 31b, and the other part is hereinafter referred to as a shank bar part 31a.

  The hammer shank 31 has two bifurcated left and right arms 31c at the rear end of the flange portion 31b on the side attached to the shank flange 30.

  As shown in FIG. 3, the both arm portions 31 c face each other with a predetermined interval in the left-right direction, and extend in parallel toward the rear.

  Each arm 31c is formed with a pin hole 31f penetrating in the left-right direction, and a cylindrical bearing 31e made of wool is attached to the pin hole 31f.

  Moreover, the shank roller 36 is attached to the lower surface near the shank rod portion 31a in the frangible portion 31b.

  The frangible portion 31b is impregnated with a synthetic resin.

[Operation]
In the grand piano having the above-described configuration, when the key 1 is pressed, the whippen 20 is pushed up through the capstan screw 1a to rotate upward about the center pin 20c, and the jack 21 and The repetition lever 22 also rotates and pushes up the shank roller 36 via the repetition lever 22.

  When further rotated, the end on the front side of the repetition lever 22 hits the button 30c and is pushed down, the repetition lever 22 rotates around the center pin 22a, and the upper end of the jack 21 hits the shank roller 36, and the shank roller 36 is moved. Push it up further.

  When the regulating button abutting portion 21b of the jack 21 abuts on the regulating button 4 and the jack 21 rotates about the center pin 21c, the abutting with the shank roller 36 abutting on the tip of the jack 21 is made. It will be solved.

  As a result, the hammer 3 that is energized until the contact between the jack 21 and the shank roller 36 is released continues to rise, and the string S made of a piano wire is struck, thereby generating a piano sound.

[Method for producing hammer shank 31]
Next, a method for manufacturing the hammer shank 31 will be described.

  Here, FIG. 4 shows a part of the manufacturing process of the hammer shank 31 in order using a perspective view of the hammer shank material 5, wherein (a) is a preparation process, (b) is a closing process, and (c). Is an impregnation step, (d) is an explanatory removal step, and (e) is an explanatory view for explaining a cutting step.

  In manufacturing the hammer shank 31 of this embodiment, as shown in FIG. 4A, first, the hammer shank material 5 is prepared (preparation step).

  The hammer shank material 5 is cut out from a raw wood (in this embodiment, a birch material, a maple material, and a side material), and is formed into a substantially flat plate shape by cutting or the like. Specifically, the hammer shank material 5 is formed with an arm portion 50 divided into two forks along one side of the four sides, and a portion adjacent to the one side is formed along one side where the arm portion 50 is provided. It is formed thicker than other parts.

  Since the thickly formed portion becomes a frenzy portion when the hammer shank 31 is cut out from the hammer shank material 5, the thickly formed portion is hereinafter referred to as a frenzy portion equivalent portion 51.

  Next, as shown in FIG. 4B, the coat portion 52 of the hammer shank material 5 excluding the portion corresponding to the frenzy portion 51 is spotted (sealing step). At this time, as shown in FIG. 4 (b), an eye stop is made so as to reach the front end 52 a of the coat portion 52. This is because the synthetic resin, which will be described later, is easily impregnated from the front end portion, so that this impregnation is surely prevented.

  Specifically, the sealing step is performed by masking the portion 51 corresponding to the frenzy part, and spraying the sealer on the coat part 52 indicated by the right-upward oblique lines in FIGS. 4 (b) and 4 (b ′). Work to be done.

  Next, as shown in FIG. 4C, a synthetic resin is impregnated into the portion corresponding to the frenzy portion 51 indicated by the diagonally downward slanting line in FIG. 4C (impregnation step).

  In this impregnation step, the synthetic resin is impregnated by WPC (Wood Plastic Composite), that is, a method of manufacturing a composite material of wood and plastics.

  Specifically, (1) The hammer shank material 5 is placed in an injection can and placed so as not to float when the resin liquid (monomer + initiator) is introduced.

  (2) The air is exhausted with a vacuum pump to reduce the pressure inside the injection can. At this time, air is not removed from the portion that has been sealed, that is, the coat portion 52.

  (3) The resin solution is gradually introduced into the injection can kept in a reduced pressure state, and the wood is completely immersed and immersed for a predetermined time. At this time, the treatment liquid does not enter the coat portion 52.

  (4) After a predetermined time, air or nitrogen gas is introduced to return the inside of the injection can to atmospheric pressure. The resin liquid is injected into the hammer shank material 5 by repeating the pressurization and pressure reduction thereafter according to the difficulty of the injection property of the hammer shank material 5.

  (5) Release pressure gradually.

  (6) In order to prevent volatilization of the resin liquid, after wrapping with polyethylene and aluminum beat, it is heated (pressed) at a temperature of 50 ° C to 80 ° C. The heating time is 0.5 to 20 hours. The heating temperature and time vary depending on the resin solution used and the type of initiator added. In the step (6), the resin injected into the hammer shank material 5 is polymerized.

  Next, as shown in FIG. 4 (d), the sealing applied to the coat portion 52 is removed (sealing removal step).

  Specifically, the sealer applied to the coat portion 52 is removed by shaving.

  Next, as shown in FIG.4 (e), the hammer shank material 5 is cut | disconnected and a some hammer shank is cut out (cutting process).

  Specifically, this cutting is performed by cutting along the direction perpendicular to the one side on which the arm portion 50 is formed, as shown by a one-dot chain line in FIG. cut.

  At this time, from the hammer shank material 5, the portion corresponding to the arm portion 50 becomes the arm portion 31c, the portion corresponding to the flange portion equivalent portion 51 becomes the flange portion 31b, and the portion corresponding to the coat portion becomes the shank rod portion 31a. The hammer shank 31 is cut out.

[Effect]
The hammer shank 31 manufactured by the manufacturing method described above has the following performance.

  The hammer shank 31 of the present embodiment is impregnated due to the flange portion 31b that is connected to the shank flange 30 being impregnated with a synthetic resin, so that the flange portion 31b absorbs moisture and expands and deforms. Can be prevented. Therefore, if this hammer shank 31 is used, the friction with the shank flange 30 will not increase due to this loss of shape.

  The hammer shank 31 is impregnated with a synthetic resin, but most of the volume is wood, so it is much lighter than when the entire hammer shank 31 is made of synthetic resin. In addition, since the hammer shank 31 is impregnated only with a portion (the frangible portion 31b) of the synthetic resin, an increase in the weight relative to the wooden hammer shank 31 not impregnated with the resin causes the entire hammer shank 31 to be synthetic resin. It is a little compared with the case of comprising.

  Therefore, if the hammer shank 31 of this embodiment is used, it is light and does not lose its shape. Therefore, the response from the key depression to the string hitting due to the friction between the hammer shank 31 and the shank flange 30 or the weight of the hammer shank 31 increases. Can be prevented.

  Further, the hammer shank 31 of the present embodiment is not impregnated with synthetic resin in the shank bar portion 31a, and the bending when hitting the string is not lost. Therefore, the piano provided with the hammer shank 31 of the present embodiment is It is possible to realize a playing feeling that is almost inferior to a piano using a wooden hammer shank that is not impregnated with synthetic resin.

  In addition, as a sealer used in the sealing step, for example, a polyol curable type (two-component curable type) having excellent adhesion to the base wood may be used and applied to the surface of the veneer using a roll coater or the like. Sealers other than polyurethane resin sealers may be used.

  Of the resin liquid used in the impregnation step, a polymerizable resin monomer (polymerizable monomer, oligomer and / or prepolymer) may be used as the monomer. Here, an example of the polymerizable monomer is vinyl. Examples thereof include acrylic monomers and acrylic monomers. Specific examples of vinyl monomers and acrylic monomers include vinyl monomers such as styrene, vinyl acetate, acrylonitrile, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate. Glycidyl methacrylate, allyl methacrylate, methacrylic acid, benzyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxy methacrylate Propyl, diethylaminoethyl methacrylate, tetrahydrofurfuryl methacrylate, ethylene glycol methacrylate, butylene glycol methacrylate, trimethyl trimethacrylate - methacrylic acid-based monomers such as trimethylolpropane and the like. Examples of the polymerizable oligomer include low polymers of these polymerizable monomers, for example, oligomers having a molecular weight of 100 or less. Examples of the polymerizable prepolymer include a prepolymer obtained by partially polymerizing a casting resin such as polymethyl methacrylate. In the present invention, it is preferable to increase the amount of the vinyl monomer for low cost. Each polymerizable monomer, polymerizable oligomer, and polymerizable prepolymer can be used singly or in combination. Moreover, the said polymeric resin monomer can use 1 type, or 2 or more types selected from the group which consists of a polymerizable monomer, a polymerizable oligomer, and a polymerizable prepolymer.

  Among the resin liquids used in the impregnation step, examples of the initiator include peroxides such as benzoyl peroxide (BPO), azo compounds such as azoisobutylnitrile (AIBN), and the like. The initiator is sufficient in a stoichiometric amount, and usually 1% or less may be added.

  Note that the present invention is not limited to the above-described embodiment as long as it meets the gist of the invention described in the claims.

DESCRIPTION OF SYMBOLS 1 ... Key, 1a ... Capstan screw, 2 ... Action, 3 ... Hammer, 4 ... Regulating button, 5 ... Hammer shank material, 10 ... Bracket, 11 ... Whippen rail, 12 ... Hammer shank rail, 20 ... Whippen, 20a ... Whippen frenzy, 20b ... arm part, 20c ... center pin, 20d ... heel part, 20e ... lever frenzy part, 20f ... arm part, 20g ... arm part, 21 ... jack, 21a ... hammer push-up part, 21b ... Regulating button contact portion, 21c ... center pin, 22 ... repetition lever, 22a ... center pin, 22b ... jack guide hole, 24 ... repetition spring, 30 ... shank flange, 30a ... placement portion, 30b ... pin mounting hole, 30c ... button, 31 ... hammer shank, 31a ... Chunk rod part, 31b ... Flange part, 31c ... Arm part, 31d ... Center pin, 31e ... Bearing, 31f ... Pin hole, 32 ... Hammer head, 36 ... Shank roller, 50 ... Arm part, 51 ... French part equivalent part, 52 ... Coat part.

Claims (4)

A wooden hammer shank for piano, in which a frenzy part having an arm part divided into two branches is formed at one end in the longitudinal direction,
A hammer shank characterized in that only the frenzy part is impregnated with a synthetic resin. The flange portion is formed at one end in the longitudinal direction of the shank rod portion,
The hammer shank according to claim 1, wherein the flange portion is formed thicker than the shank rod portion in the direction in which the arms are arranged. A method for producing a hammer shank according to any one of claims 1 and 2,
A preparation step of preparing a wooden hammer shank material capable of cutting a plurality of hammer shanks when the arm portion divided into two branches is formed along one side and cut along a direction orthogonal to the one side;
Of the hammer shank material, an eye stop step for closing the coat portion excluding the portion corresponding to the frenzy portion that forms the frenzy portion when cut out,
An impregnation step of impregnating a synthetic resin into a portion corresponding to the frenzy part;
An eye removal step for removing the eyelet of the coat portion;
And a cutting step of cutting the hammer shank material to cut out a plurality of hammer shanks. In the manufacturing method of the hammer shank of Claim 3,
In the sealing step, a sealer agent is applied to the coat part,
The hammer shank manufacturing method, wherein, in the eye removal step, the sealer applied to the coat portion is removed by shaving.

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