JP2001276280A - Racket frame - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a racket frame allowing a comfortable sense of stroking a ball to be obtained at the time of stroke and making fatigue hard to cause to the wrist, elbow, and the like, of a player by reducing the shock and vibration propagated to the hand of the player from a grip part at the time of stroke to a satisfactory level. SOLUTION: A grip part 5 is formed in a three-layer structure comprising the body layer of the grip 7 made of a fiber reinforced resin, a viscoelastic material layer 8 covering the body layer of the grip 7 and a thin hard shell 9 that is arranged in the circumference of the viscoelastic material layer 8 and is independent from the body layer of the grip 7 by the viscoelastic material layer 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a racket frame (hereinafter, referred to as a racket frame) used in tennis, badminton, and the like.

[0002]

2. Description of the Related Art A racket frame 3 of this type has conventionally been used.
As shown in FIG. 14 and FIG. 15, the configuration 1 has a tubular structure in which a hitting portion 32, a shaft portion 33, and a grip portion 34 are integrally formed by an outer shell 35 made of a fiber-reinforced resin. And an outer shell 35 constituting the grip portion 34
Generally has a structure in which a grip member 36 made of a foamed synthetic resin or a non-foamed synthetic resin material or the like is attached to the periphery.

[0003] Normally, impact and vibration generated when a ball is hit with a racket frame are transmitted from a hitting portion 32 of a racket frame 31 to a player's hand through a grip portion 34. In the racket frame 31 having the structure, the grip member 3 attached to the grip portion 34 can reduce the impact at the time of impact and absorb the vibration.
6 depends only on the elasticity of the ball itself, and thus has a disadvantage that it is inferior in shock absorbing and vibration absorbing ability, and that vibrations and shocks generated at the time of impact are easily transmitted to the player's hand without being attenuated. Was. As a result, not only is the unpleasant vibration transmitted to the player, the feel at impact is impaired, but in particular, in recent racket frames, in order to improve operability, the weight of the racket frame itself has been reduced, and rebound characteristics have been reduced. In order to improve the racket frame, the movement of increasing the rigidity of the racket frame is progressing year by year, and in parallel with this, the impact when hitting causes a physical burden on the player, and the fatigue on the wrist and elbow etc. increases , There is a risk of inducing sports obstacles such as tennis elbows.

[0004] For this reason, various methods have been proposed for suppressing the impact and vibration transmitted to the player's hand when hitting.

For example, Japanese Utility Model Application Laid-Open No. 61-188770 discloses that an elastic material such as rubber, sponge, or elastomer is provided in an FRP outer shell 37 on a shaft end portion side including a grip portion, as shown in FIGS. A racket frame has been proposed and known in which the vibration damping member 38 is integrally buried and molded so that the impact at the time of impact is buffered by the elastic material and the vibration absorbing ability is improved. .

Japanese Unexamined Patent Application Publication No. 9-664 discloses a viscoelastic material at a part of the interface between the grip portion 39 and the surface material 40 attached to the grip portion 39, as shown in FIGS. A racket frame configured to reduce the impact transmitted to the hand at the time of hitting by interposing the material 41 has been proposed and known.

[0007]

However, such conventionally known racket frames have the following disadvantages.

That is, as proposed in Japanese Utility Model Unexamined Publication No. Sho 61-188770, the F on the shaft end portion side including the grip portion is provided.
In a configuration in which a vibration damping member 38 made of an elastic material such as rubber, sponge, or elastomer is integrally embedded in the RP outer shell 37, as shown in FIG. However, the vibration damping member 38 is hardly deformed in the compression direction y against the shock and vibration generated at the time of impact since the hard FRP shell 37 is constrained between the layers, and the shear direction x Since only deformation in the direction of vibration is permitted, the loss energy of the vibration damping member 38 can be increased only in the above-described shear direction x. As a result, the effect of absorbing vibration at the time of impact is somewhat reduced. However, there is a problem that the effect is not so much obtained in the characteristics of impact relaxation.

Further, since this is configured so that a hard grip member 42 made of a hard urethane foam resin, an ABS resin or the like is arranged around the shaft end portion, the vibration damping member 38 is provided. Is further inhibited in the compression direction y, so that the impact is not easily reduced by the vibration damping member 38 at the time of impact, and the arrangement of the grip member 42 and the mass of the racket frame are bulky. Therefore, there is a problem that the operability is adversely affected.

Further, as proposed in Japanese Patent Application Laid-Open No. 9-664, there is no configuration in which a viscoelastic material 41 is interposed at a part of the interface between the grip portion 39 and the surface material 40. As shown in FIG. 19, the viscoelastic material 41 is deformed in the compression direction y in response to the impact at the time of impact,
Since the loss energy of the viscoelastic material 41 in the same direction can be increased, the shock transmitted to the player's hand can be effectively reduced, but the deformation of the viscoelastic material 41 in the shear direction x is The problem is that it only works in a part of the area gripped by the player's hand and does not sufficiently increase the energy loss in the same direction. was there.

Further, since the grip force of the player's hand is transmitted to the racket frame via the viscoelastic material 41, the gripping property is likely to be unstable when the grip portion 39 is gripped. There is a problem that the operability of the racket frame at the time is reduced. Therefore, in order to prevent such a problem, the viscoelastic material 41 is provided on the grip portion 3.
9 cannot be arranged on the whole,
However, there is a problem in that it is difficult to obtain a sufficient effect with respect to the impact mitigation at the time of hitting or the vibration absorbing ability.

In view of the above problems, the present invention reduces both the impact and vibration transmitted from the grip portion to the player's hand at the time of hitting to a satisfactory level, and provides a comfortable shot feeling at the time of hitting. It is an object of the present invention to provide a racket frame that can provide a racket frame in which wrists, elbows and the like of a player are hardly fatigued.

[0013]

In order to achieve the above object, the present invention has the following arrangement. That is, claim 1 of the present invention is a racket frame including a hitting portion, a shaft portion, and a grip portion, wherein the grip portion is formed by a fiber-reinforced resin outer shell. A tubular grip body layer formed continuously and integrally from the portion, a viscoelastic material layer covering a part or the whole of the grip body layer, and a viscoelastic material layer A racket frame characterized in that the racket frame is formed in a three-layer structure including the grip body layer and an independent thin hard shell.

According to a second aspect of the present invention, in the racket frame according to the first aspect, the viscoelastic material layer and the hard shell are disposed in a concave portion provided on at least a part of a surface layer of the grip body layer. It is characterized by being provided.

According to a third aspect of the present invention, in the racket frame according to the second aspect, the viscoelastic material layer is formed in a shape conforming to the concave portion, and the hard shell is disposed on a surface layer thereof. And a second concave portion for performing the operation.

According to a fourth aspect of the present invention, in the racket frame according to the third aspect, the opening end of the second concave portion provided in the viscoelastic material layer is formed by the concave end provided in the grip body layer. It is characterized by being separated from the opening end by at least 5 mm or more.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to preferred embodiments described in detail with reference to the drawings. FIG. 1 is a front view of a racket frame of the present embodiment, and FIG. 2 is an enlarged explanatory view of a grip portion showing a state where a surface material such as grip leather and an end cap are removed from the racket frame of FIG. 3 is a cross-sectional end surface reference diagram at the line AA in FIG. 2, FIG. 4 is a cross-sectional diagram of a main portion at the line BB in FIG.
FIG. 3 illustrates a configuration explanatory diagram of FIG. 2.

That is, the racket frame 1 of the present embodiment is
As shown in FIGS. 1 and 2, the gut 2 includes a hitting portion 3 having a gut net surface formed by stretching, a shaft portion 4, and a grip portion 5. The grip part 5
The hitting portion 3 and the outer shell 6 made of fiber reinforced resin,
A tubular grip body layer 7 continuously and integrally formed from the shaft portion 4; a viscoelastic material layer 8 coated on the outer periphery of the grip body layer 7; It has a three-layer structure composed of the grip main body layer 7 and an independent thin hard shell 9 by a layer 8.

In this embodiment, as shown in FIGS. 2 to 5, the surface of the grip body layer 7 having an octagonal cross section is
The concave recess 11 is provided around the length range of 40 mm to 150 mm from the grip end 10 side,
It has a configuration in which a viscoelastic material layer 8 having a shape and a size matching the shape of the concave portion 11 and a thin hard shell 9 described later are disposed on the surface layer in the concave portion 11. ing.

The hard shell 9 has a smaller shape and size than the viscoelastic material layer 8, and is provided on the surface layer of the viscoelastic material layer 8 over a length range of 30 to 140 mm from the grip end 10 side. It has a configuration in which it is disposed in the peripherally provided second concave portion 12. The opening end 13 of the second recess 12 in which the hard shell 9 is disposed is 5 mm from the opening end 14 of the recess 11 provided in the grip body layer 7.
A part of the viscoelastic material layer 8 is exposed on a surface of a grip at a space between the concave portions, and a step between the surface of the hard shell 9 and a step is formed. It is configured to form a flat surface.

Therefore, in the racket frame 1 of the present embodiment, the grip portion 5 to be gripped by the player is formed in a three-layer structure as described above, and the viscoelastic material layer 8 is provided in the middle layer. On its outside, a thin hard shell 9 independent of the grip body layer 7 by the viscoelastic material layer 8
3 and 4, the viscoelastic material layer 8 is not restrained by a hard outer shell like a conventional racket frame, as shown in FIGS.
The deformation in the compression direction y and the shear direction x becomes free,
The loss energy of the viscoelastic material itself can be greatly increased. Therefore, with respect to an impact generated at the time of impact, the loss energy of the viscoelastic material itself is increased by the deformation of the viscoelastic material layer 8 in the compression direction y, and the impact transmitted to the player is greatly reduced. It becomes possible.

Further, with respect to the vibration generated at the time of hitting, the viscoelastic material layer 8 is deformed in the shearing direction x, thereby increasing the loss energy of the viscoelastic material itself and attenuating the vibration transmitted to the player. It becomes possible. In particular, in the present embodiment, since the thin hard shell 9 independent of the grip body layer 7 is disposed on the surface layer of the viscoelastic material layer 8, the area of the area gripped by the player's hand is different from the conventional case. Only the viscoelastic material does not deform in the shear direction x, and the viscoelastic material layer 8 in the area covered by the hard shell 9 exhibits a relatively deforming movement, so that it is much more dramatic than in the past. At the same time, the vibration absorbing ability is enhanced, and at the same time, the shape retention is maintained by the hard shell 9, so that the gripping ability when the player grips is improved.

The racket frame 1 of the present embodiment as described above.
For example, a plurality of prepreg sheets 16 for racket ram forming are laminated around a tube 15 for internal pressure forming, and the prepreg sheets 16 are arranged in a cavity having a mold frame shape. In a normal manufacturing method of a racket frame made of fiber-reinforced resin, such as injecting compressed air or the like into the inside of the rack 15 and heating, as shown in FIG.
A sheet-like or tubular viscoelastic material 17 is coated on the outer periphery of a portion corresponding to the grip of the laminated prepreg sheet 16. After that, the surface layer is coated with a thin hard shell material 18 having a shorter length in the longitudinal direction than the viscoelastic material 17, loaded into the cavity, and heated and pressed to form a means. Can be In addition to the above method, although not shown, the recessed portion 1 is previously formed in the grip body layer 7 by the normal internal pressure molding method described above.
After forming a molded article provided with the viscoelastic material 17, the viscoelastic material 17 is disposed on the bottom surface of the concave portion 11.
It is also possible to adopt a method in which the hard shell 9 is formed by injection-molding a hard resin material or the like on the surface layer 7.

As the main reinforcing fibers constituting the racket frame 1 made of the fiber-reinforced resin of the present embodiment, various types such as carbon fibers, glass fibers, boron fibers, and aromatic polyamide fibers can be used. Carbon fibers are also preferable in terms of weight and cost. As the matrix resin, epoxy resin, nylon resin, etc. can be used,
Epoxy resins are preferred in terms of strength and durability.

The material forming the viscoelastic material layer 8 is preferably a soft material having good moldability and a small difference in hardness due to a temperature change from a low temperature to a high temperature. Examples of preferred materials include, for example, styrene-based elastomers, polyester elastomers, PVC-based elastomers, EVA,
It is preferably formed of an elastic material such as EPDM, thermoplastic polyurethane elastomer, polyamide elastomer, or a viscoelastic material.

Further, the material forming the hard shell 9 has good adhesion to the material forming the viscoelastic material layer 8, is lightweight, and retains its shape when gripped. A material having a sagging rigidity is desirable. For example, as an example, a fiber-reinforced resin material using carbon fiber, glass fiber, boron fiber, aromatic polyamide fiber, or the like as a reinforcing material has high strength and rigidity and is suitable. These materials may be cured and formed after being coated on the surface layer of the viscoelastic material layer in the state of a prepreg sheet, or in a state where the viscoelastic material is preliminarily formed into a sheet or a tube. The surface layer of the material layer may be covered. In addition,
It is also possible to use an injection molded product made of a thermoplastic resin such as an ABS resin, a polypropylene resin, and a vinyl chloride resin.

In the present embodiment, an example in which the region for forming the grip portion 5 in a three-layer structure is provided within the range of 40 mm to 150 mm from the grip end 10 as described above has been described. However, as shown in FIG. 7, the entire length range of the grip portion 5 in the longitudinal direction can be configured in the three-layer structure as described above. In this case, although the mass is relatively easily increased in the grip portion, even if any portion of the grip portion is gripped, good shock mitigation and vibration absorbing ability can always be obtained. FIG. 9
As shown in the figure, it is also possible to configure only the middle region in the longitudinal direction of the grip portion 5 into a three-layer structure. In this case, good shock mitigation and light weight of the racket frame while exhibiting vibration absorbing ability can be achieved. It can be realized.

Further, in the arrangement of the hard shell 9, as shown in the examples of FIGS.
May be disposed so as to cover the entire outer periphery of the hard shell 9, but as shown in FIG. 3, by forming the hard shell 9 into a shape smaller than the viscoelastic material layer 8 as in the above-described embodiment. The opening end 13 of the second recess 12 in which the hard shell 9 is disposed is separated from the opening end 14 of the recess 11 provided in the grip body layer 7, The viscoelastic material layer 8 may be formed so that a part of the viscoelastic material layer 8 is exposed on the grip surface at the space between the recesses. In this case, in particular, when the grip portion 5 is molded in the mold, the matrix resin flowing out of the prepreg constituting the grip body layer 7 goes around the hard shell 9 and integrates the two. Since such troubles can be prevented, it becomes more preferable. The separation width R between the opening ends varies depending on the viscosity of the matrix resin used, molding conditions, and the like, but is generally about 5 mm.
The distance is preferably at least 10 mm or more. Note that the separation width R between the opening ends is 5 m as described above.
When the length is shorter than m, the grip body layer 7 and the hard shell 9 are easily bonded and integrated by the matrix resin when the grip portion 5 is formed, and it is difficult to obtain good shock relaxation and vibration absorption efficiency. . Therefore, the above-mentioned bonded portion must be removed in a later step, which is not preferable because the molding step requires time and effort.

[0029]

EXAMPLES In order to confirm the effect of the present invention, racket frames for tennis according to Example 1 and Comparative Examples 1 to 3 were prepared.

That is, the racket frame 1 prepared as the first embodiment has a viscoelastic material layer 8 made of EPDM on the surface layer of the grip body layer 7 made of fiber reinforced resin, as shown in FIG. On the surface of the viscoelastic material layer 8, one having a three-layer structure in which a hard shell 9 made of a thin shell made of a fiber-reinforced resin independent of the grip body layer 7 was provided. In addition, the viscoelastic material layer 8 is provided in the concave portion 11 formed in the surface layer of the grip body layer 7 and the hard shell 9 is provided in the viscoelastic material layer 8 in the same manner as in the above-described embodiment. It was set as the structure provided in the 2nd concave part 12 formed in the surface layer, respectively. The extension length of the viscoelastic material layer 8 in the grip longitudinal direction is 90 mm from the grip end 10, and the extension length of the hard shell 9 is 7 from the grip end 10.
0 mm.

As Comparative Example 1, as shown in FIG. 10, a grip member 5 composed of only a grip body layer 7 made of fiber reinforced resin was prepared. As Comparative Example 2, as shown in FIG. 11, only the viscoelastic material layer 8 was provided on the surface of the grip body layer 7 made of fiber reinforced resin.
The material and the disposition length of the viscoelastic material layer 8 were the same as those of the first embodiment. Further, as a comparative example 3, as shown in FIG. 12, a viscoelastic material layer 8 is provided between the grip body layers 7 made of fiber reinforced resin. The length was prepared in the same manner as in Example 1 above.

The following tests were carried out on the racket frames of Example 1 and Comparative Examples 1 to 3 in order to confirm the impact mitigation at the time of impact and the ability to absorb vibration. That is, as shown in FIG.
The racket frame attached with the rubber is suspended by a rubber belt 20, and when the gut net surface stretched on the hitting portion is hit with the impulse hammer 21, the impulse hammer 21
The FFT analyzer 23 measures the acceleration signal generated by the accelerometer 22 attached to the grip and the acceleration signal generated by the accelerometer 19 attached to the grip, and obtains the response strength from the ratio to obtain the response strength. The index was used. The smaller this ratio, the higher the degree of impact relaxation. In the above test, a logarithmic decay rate was obtained from an acceleration waveform generated in the accelerometer 19 attached to the grip portion 5 and used as an index of vibration absorption. The greater the logarithmic damping rate, the higher the vibration damping property appears. The measurement results at this time are shown in Table 1 below.

[0033]

[Table 1]

From the above measurement results, the racket frame 1 of the first embodiment has the characteristics of both the shock relaxation and the vibration absorbing ability which are smaller than those of the racket frames of the first to third comparative examples.
It was confirmed that an excellent effect was obtained.

[0035]

As described above, according to the present invention, since the loss energy due to the deformation of the viscoelastic material layer disposed in the grip portion in the compression direction and the shear direction can be increased, the grip at the time of hitting can be improved. The impact and vibration transmitted from the part to the player's hand can both be reduced to a satisfactory level, providing a comfortable shot feeling when hitting and significantly reducing the fatigue applied to the player's wrist, elbow, etc. Is what you can do.

[Brief description of the drawings]

FIG. 1 is a front view of a racket frame according to the present embodiment.

FIG. 2 is an enlarged explanatory view of a grip portion of the racket frame of the embodiment.

FIG. 3 is a sectional end view reference view taken along the line AA of FIG. 2;

FIG. 4 is a cross-sectional end view of a main part taken along line BB in FIG.

FIG. 5 is an explanatory diagram of a configuration of a grip portion of the racket frame of the embodiment.

FIG. 6 is an explanatory view illustrating a method of manufacturing the racket frame according to the embodiment.

FIG. 7 is an end view of a grip portion showing another embodiment.

FIG. 8 is an end view of a grip portion showing another embodiment.

FIG. 9 is an end view of a grip portion showing another embodiment.

FIG. 10 is a configuration explanatory view of a comparative example 1.

FIG. 11 is a configuration explanatory view of a comparative example 2.

FIG. 12 is a configuration explanatory view of a comparative example 3.

FIG. 13 is an explanatory diagram showing a test method.

FIG. 14 is a front view of a conventional racket frame.

FIG. 15 is an explanatory end view of a grip portion of a conventional racket frame.

FIG. 16 is an explanatory end view of a grip portion of a conventional racket frame.

FIG. 17 is an explanatory end view of a grip portion of a conventional racket frame.

FIG. 18 is an end view of a grip portion of a conventional racket frame.

FIG. 19 is an explanatory end view of a grip portion of a conventional racket frame.

[Explanation of symbols]

 Reference Signs List 1 racket frame 2 gut 3 hitting part 4 shaft part 5 grip part 6 outer shell 7 grip body layer 8 viscoelastic material layer 9 hard shell 10 grip end 11 concave concave part 12 second concave concave part 13 open end 14 open end Part 15 tube 16 prepreg sheet 17 viscoelastic material 18 hard shell material 19 accelerometer 20 belt 21 impulse hammer 22 accelerometer 23 FFT analyzer 31 racket frame 32 hitting part 33 shaft part 34 grip part 35 outer shell 36 grip member 37 FRP outer shell 38 Vibration damping member 39 Grip part 40 Exterior material 41 Viscoelastic material 42 Grip member

Claims (4)

[Claims] 1. A racket frame comprising a hitting portion, a shaft portion, and a grip portion, wherein the grip portion is continuous from the hitting portion and the shaft portion by an outer shell made of fiber reinforced resin. A tubular grip body layer formed integrally, a viscoelastic material layer covering a part or the entirety of the grip body layer, and disposed on the outer periphery thereof, and the grip body layer is A racket frame formed in a three-layer structure including an independent thin hard shell. 2. The racket according to claim 1, wherein the viscoelastic material layer and the hard shell are disposed in a concave portion provided on at least a part of a surface of the grip body layer. flame. 3. The viscoelastic material layer is formed in a shape conforming to the concave portion, and has a second concave portion for disposing the hard shell on a surface layer thereof. The racket frame according to claim 2, wherein: 4. The method according to claim 1, wherein an opening end of the second recess provided in the viscoelastic material layer is separated from the opening end of the recess provided in the grip body layer by at least 5 mm. The racket frame according to claim 3, characterized in that: