JPH03228779A - Racket - Google Patents

Abstract

PURPOSE:To damp the vibration transferred to a frame via the function of the frame itself by fixing a vibration suppressor unit on at least part of a member constituting a racket. CONSTITUTION:A vibration suppressor unit 5 constituted of a vibration suppressing material 7 and restricting material made of a raw material with the strength end rigidity higher than those of the vibration suppressing material 7 is fixed on at least part of a member constituting a racket. The vibration suppressor unit 5 constituted of a shock absorbing material 9, the vibration suppressing material 7 and the layered shock absorbing material incorporated in it is stored near the ends of guts 1 at the top section of a frame 2 via a restricting plate 8 with a fixed thickness, its outer edge section is closed by a frame mold to form a casing structure, for example, and the restricting plate 8 is fixed to the upper end section of the frame 2 via a separate shock absorbing material 9 with stoppers 11. The shock vibration transferred from the guts 1 to the frame 2, a shaft and a grip when a ball is driven can be effectively damped.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a racket that significantly suppresses impact vibrations when hitting a ball and that allows for comfortable play, particularly a tennis racket.

[Prior Art] Generally, the frames of rackets such as hard tennis rackets in which the sweet spot is a problem are made of lightweight, strong and rigid materials.

That is, wood, aluminum alloy, fiber-reinforced synthetic resin (FRP), etc. are used as the aggregate for such rackets.

Although these materials inherently have relatively good vibration damping properties, they are not always sufficient in their ability to rapidly and effectively reduce impact vibrations when a ball is hit.

Furthermore, in order to reduce and alleviate impact vibrations when hitting a ball, rubber or soft synthetic resin molded products are installed between the racket guts or crimped onto the gut surfaces. Although this method is effective to a small extent in suppressing the vibration of the gut itself, it is not sufficient. Furthermore, the vibration propagated from the guts to the frame was not damped by the function of the frame itself.

[Problems to be Solved by the Invention] In other words, in the conventional racket, the vibration propagated to the frame during impact vibration when hitting a ball is propagated to the arm and elbow through the shaft and grip, causing damage to the wrist, arm, elbow, etc. This resulted in accumulated fatigue. In particular, if the ball is hit off the center of the gut (the so-called sweet spot), an unpleasant vibration or stiffness may be experienced, which may lead to injuries such as tennis elbow.

In view of the drawbacks of conventional rackets, the present invention is capable of rapidly and effectively attenuating impact vibrations when hitting a ball.
To provide a racket, especially a tennis racket, which allows players to play comfortably and reduces fatigue in their arms and elbows.

[Means to solve problems] The following measures will be taken to achieve the above objectives.

That is, in the racket of the present invention, a vibration suppressing body unit consisting of a vibration suppressing material and a restraining material made of a material having higher strength and rigidity than the vibration suppressing material is fixed to at least a portion of the members constituting the racket. It is characterized by:

[Function] According to the present invention, when a vibration suppressing material is fixed to a tennis, squash, or badminton racket having a gut surface in combination with a restraining material described later, the impact vibrations propagated from the gut when hitting a ball are extremely effectively damped. This is what we discovered.

1 to 3 are schematic diagrams showing an example of the racket of the present invention. In this example, gut 1, frame 2, shaft 3
A vibration suppressing body unit 5 consisting of a vibration suppressing material 7 and plate-shaped restraining materials 8 and 10 as shown in FIG. It is shown.

The band 6 includes a vibration suppressing material 7 and a restraining material 8 as shown in FIG.
The shaft 3 is directly fixed integrally and mechanically through the hole 10 provided in the shaft 3.

Such vibration suppressing materials may be wood materials, elastic rubber, synthetic resins, cork, felt materials, etc., but metals such as copper and lead, materials with high specific gravity such as ceramics, and mixtures of these materials may also be used. However, it is particularly preferable to use a damping resin material with high vibration damping ability. Such a damping resin material is preferable because it can be processed into various shapes such as a desired shape, such as a protrusion shape, a plate shape, and a film shape.

Next, the restraining material has the function of stably fixing (installing) the vibration suppressing material on or inside the vibration suppressing material.

The material constituting the restraining material may include materials having higher strength and rigidity than the vibration suppressing material, such as various metals,
Materials made of plastic, wood, etc. can be used. Among such materials, a material having higher wear resistance than the vibration suppressing material is preferable because it can provide a vibration suppressing unit with excellent durability.

The restraining material is a composite and integrated material with a vibration suppressing material,
Furthermore, it is preferable because the vibration damping function of the vibration suppressing material can be effectively exhibited.

In such a vibration suppressor unit, a shock absorbing material is interposed or combined between the vibration suppressing material and the restraining material, or the buffer material is further interposed or combined with the inner layer of the vibration suppressing material. Accordingly, the vibration damping ability of the vibration suppressing material itself can be further improved.

Here, the cushioning material preferably has a compression hardness of 0.5% when compressed at 25% as specified in JIS K6767. 00
5-5. 0 kg/cm2, more preferably 0, 0
08-3. Those in the range of 0 kg/cJ may be excellent in improving the vibration damping ability.

The compression hardness is measured using a compression hardness tester (manufactured by Daiei Kagaku Seiki Seisakusho) in a temperature-controlled room at 20°C. The test piece is 50mm long, 50mm wide, and about 25mm thick.
Use a rectangular parallelepiped. The thickness of the central part of the test piece was measured, and then the test piece was placed in a predetermined position in the testing machine, compressed by 25% of the initial thickness at a compression speed of 10 mm/mn, and then stopped. The load (P
) and calculate the compression hardness (H) using the following formula.

P W・l where P: Load after 20 seconds under 25% compression (kg
) W: Width (cm) of test piece 1: // Length (cm) As such a buffering material, the following can be used.

Examples of inorganic elastomers include rubbery sulfur,
Silicon fluoride polymers, phosphorus-based, silicon-based (siloxane-based polymers,) phosphacene-based elastomers (phosphorous and nitrogen skeletons), etc. Polymer gel-based products include, for example, polyvinyl alcohol hydrogel, sodium acrylate/
Acrylamide copolymer gel, etc. Organic elastomers include, for example, polyvinyl chloride, polyurethane, polyamide, polystyrene, ethylene vinyl acetate copolymer, ethylene ethyl acrylate, polyolefin, polyester, and epoxy. Examples of rubber elastomers include natural rubber, styrene-butadiene rubber, nitrile rubber, isoprene rubber, hydrin rubber, and chloroprene rubber. Examples of foamed plastics include polyurethane and polystyrene. system, polyethylene system, fluorine system, E
VA-based, phenol-based, PvC-based, polyuria-based, etc. The present invention will be further explained with reference to the drawings.

FIG. 4 shows a vibration suppressor unit 5 constructed by interposing a buffer material 9 in addition to the vibration suppressor 7 and restraint material 8 shown in FIG.

FIG. 5 shows how the vibration suppressing material unit 5 shown in FIG. 4 is fixed to the shaft portion 3 of the racket with a band 6 as shown in FIG.
FIG. 3 is a cross-sectional view showing the state seen along the X+-X+' axis when the device is attached (installed).

6(a), (b), and (c) show examples of the structure of the vibration damping unit 5 of the present invention, but the vibration suppressing unit 5 of the present invention is not limited to these structures. It is not something that will be done.

(A) The figure shows a vibration suppressor unit 5 having a structure in which a vibration suppressor 7 is laminated with one layer of buffer material 9 in the vertical and horizontal directions, and a restraint material 8 is incorporated through the buffer material 9. shows.

(B) In addition to the structure shown in FIG. (A), a restraining member 8 is additionally configured in the center of the vibration suppressing member 7.
A vibration suppressor unit 5 having a structure in which cushioning materials 9 are incorporated on both sides of the vibration suppressor unit 5 is shown.

Figure (c) shows a vibration suppressor unit 5 having a structure that is a further modification of the structure shown in figure (b), in which the restraining material 8 covers the entirety of the vibration suppressing material 7 and the cushioning material 9.

The above-described vibration suppressor unit structures are preferably combined and integrated to further improve the vibration damping effect.

In any case, by adopting such a uni-seat structure, the damping performance of the vibration suppressing material 7 itself and the damping function obtained by combining this with the restraining material 8 and the cushioning material 9 in addition to these are improved. Acting synergistically, extremely good vibration damping ability can be achieved.

The vibration suppressor unit 5 of the present invention can achieve its effects even if it is fixed and attached to any part of the racket. For example, it can be fixed to the top of the frame part 2. An example is shown below.

7(a) and (b) are examples in which the arc-shaped vibration suppressor unit 5 is attached to the zenith part of the frame 2, and FIGS. This is an example in which it is loaded into the frame 2.

FIG. 7(a) is a plan view showing the vibration suppressor unit 5 attached to the zenith portion of the frame portion 2 via the stopper 11, and FIG. The cross-sectional structure of the vibration suppressor unit 5 viewed along the X2' axis is shown.

Even if the vibration suppressor unit 5 is fixed to the zenith portion of the frame 2 of the racket in this manner, a high vibration suppressing effect can be obtained.

Next, a specific structure will be explained using the example shown in FIG. 7(b).

(B) The figure shows a vibration suppressor unit 5 consisting of a shock absorbing material 9, a vibration suppressing material 7, and a layered shock absorbing material 9 incorporated therein, located close to the end of the gut 1 at the top of the frame 2. A casing structure is shown in which the casing is housed through a restraining plate 8 having a constant thickness, and the outer edge of the casing is closed with a frame shape. The restraint plate 8 is fixed to the upper end of the frame 2 with a stopper 11 via another cushioning material 9.

As a method of fixing the vibration suppressor unit 5 to the top of the frame 2, the vibration suppressor unit 5 may be incorporated into the frame 2 as shown in FIG.

8(a) is a plan view, and FIG. 8(b) shows the cross-sectional structure of the zenith portion seen along the X3-X3' axis in FIG. 8(a).

(B) As can be seen from the figure, in this example, a hollow inverted U-shaped casing part is provided with the zenith facing the tip, and the vibration suppressing material 7 is placed here, and the cushioning material The vibration suppressing body unit 5 has a structure in which the vibration suppressing body unit 5 is housed through the holder 9 and sealed with a lid from the outer edge. In this example, the casing part within the frame 2 is specifically used as a part of the unit 5, but if the frame 2 is a hollow tube, a method of loading it into the tube may also be used.

As the vibration suppressing material of the present invention, damping resin materials are particularly preferable, but such materials include, for example, rubber or synthetic resin compositions with relatively high specific gravity, and metals with high specific gravity such as lead in these resins. Materials containing metal fibers or metal fibers can be used.

Among these materials, at least one selected from epoxy resins that have fluidity at room temperature to 100°C, polyamide resins that have fluidity at room temperature to 100°C, and inorganic fillers, especially graphite, ferrite, and mica; A material consisting of a thermosetting synthetic resin composition containing as a main component is preferably used. Such a resin composition has a high degree of processing freedom and is flexible, and furthermore, the resin material after curing exhibits extremely excellent vibration damping curing.

In the above resin composition, the epoxy resin having fluidity at room temperature to 100°C is preferably a resin having at least two or more glycidyl ether groups, and more preferably has a viscosity of 1 to 300°C at 25°C. Poise, epoxy equivalent weight is 100-500, molecular weight is 200-100
Specifically, for example, "Epicoat 828.827.834.807" (manufactured by Yuka Shell Chemical Co., Ltd.) can be used.

In addition, as a polyamide resin having fluidity at room temperature to 100°C, preferably the viscosity at 25°C is 3 to 2000.
Poise, more preferably one having an amine value of 100 to 800 is preferred since it acts effectively as a curing agent for epoxy resins and as an agent for imparting flexibility to the resin after curing. Specifically, for example, “Tomide #225-X, #215
-X.

#225" (manufactured by Fuji Kasei Co., Ltd.), "Persamide 930.115" (manufactured by General Mills), "Epon-V15" (manufactured by Shell), etc. can be used.

The above components are preferably blended in the following proportions.

That is, the blending amount of polyamide resin with respect to 100 parts of epoxy resin is 100 to 800 parts, more preferably 2 parts.
00 to 500 parts, and the inorganic filler is 30 to 120 parts, more preferably 40 to 100 parts, based on 100 parts of the total amount of these resins (including monoglycidyl ether, which will be described later). .

Among the vibration-damping resin materials thus obtained, those having a vibration loss coefficient of 0.02 or more at room temperature are preferred because they have a large damping effect on impact vibrations from guts.

The above-mentioned vibration loss coefficient is measured as follows.

That is, after pasting a 10 mm thick synthetic resin onto a 5 mm thick steel plate using a two-component poxy adhesive,
After leaving the adhesive for a while and hardening, the MT of the US military discipline
Measure the vibration damping waveform according to LP-22581B,
Find the vibration loss coefficient (η) using the following formula.

a, Attenuation rate (DECAY RATE) D,) (dB/5ec) - (F/N) 20 lo
g(A+/A2)b, effective attenuation factor (EFFECTI
VE DECAY RATDDe(dB/5ec)
-ri. -DB PERCENT CRIT
ICAL DAMPING)C/Co (%) -(1
83xDe)/F where, F, Natural frequency N of the sample bonding plate: Number of calculated periods A+: Maximum amplitude in N A2: Minimum amplitude Do in N: Attenuation rate of sample bonding plate D6: Original Damping rate d of steel plate, vibration loss coefficient (η) η = (C/CC) 150 As the vibration suppressing material used in the present invention, 20°C
It is preferable that the above-mentioned vibration loss coefficient in the frequency range of 50 Hz to 5 kHz is 0.04 or more because it exhibits particularly excellent vibration damping effect.

Next, a method for measuring the apparent vibration loss coefficient of a racket will be described below.

That is, a micro-acceleration pickup is attached to the center of the grip of the racket, the tip of the frame is tapped with a hammer, the attenuation waveform of the vibration is measured with an FFT analyzer, and the waveform is analyzed using a microcomputer (manufactured by NEC Corporation). According to the formula of MILP, -22581B,
Measure the vibration loss coefficient (η).

The vibration loss coefficient of the racket of the present invention is preferably 0.
01 or more, more preferably 0.02 or more, particularly preferably 0.04 or more, and exhibits an excellent vibration damping effect in practical use.

In other words, a racket with a vibration loss coefficient of less than 0.01 has no superiority over conventional rackets, and causes unpleasant vibrations to propagate when the ball is hit off the sweet spot.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 A resin material made of a resin composition having the following formulations (1) to (5) is used as a vibration suppressing material.

(1) Epoxy resin 14.5 parts (Epicote #828, manufactured by Yuka Shell ■) (2) Octadecyl glycidyl ether 2.9 parts (3) Amide resin
Part 31.1 (Tomide #225-
X, manufactured by Fuji Kasei ■) (4) Tris (dimethylamino)
1.5 parts of methylphenol (5) 51.0 parts of graphite A damping plate with a thickness of 10 mm was made using the above resin composition. The vibration loss coefficient of this plate at a room temperature of 20° C. was measured by the method described above and was found to be 0.05 in the frequency range from 50 Hz to 5 kHz.

This board has a base of 45 mm, a height of 30 mm (higher side) and 25 mm.
It is cut into a trapezoid of mm (lower side), and a 0.0 mm thick trapezoid is placed on the surface as a restraining material. Glue 5mm thin steel plate 9.10,
A vibration suppressor unit was formed.

Drill a hole in this vibration suppressor unit as shown in Figure 3,
As shown in Figure 2, a band is attached to the shaft of the racket near the center of gravity. The weight increase of this racket was 16g.

The apparent vibration loss of this racket was measured using the method described above. The results are shown in Table 1.

Example 2 The vibration suppressor unit shown in FIG. 6(A) was formed using the vibration suppressor produced in Example 1. The cushioning material laminated on both sides and in the horizontal direction in Figure 6 (a) is a polyolefin foam material made of organic elastomer with a thickness of 1 mm (Torepef made by Toshi: compressive hardness I-). 1
= 0, 16 kg/car), and the rubber elastomer chloroprene rubber (compression hardness H = 0.2 kg/cm) was used as the cushioning material for the center of (a).
2) was used.

It was fixed to the shaft of the racket using a band as shown in FIG.

The weight increase of this racket was 18g.

The apparent vibration loss coefficient of this racket was measured in the same manner as in Example 1 and is shown in Table 1.

Example 3 A racket as shown in FIGS. 7(a) and 7(b) was made in which a vibration suppressor unit was attached to the zenith portion of the frame.

The same vibration suppressing material as in Example 1 was used, and the cushioning material covering the vibration suppressing material/cushioning material laminate was a polyolefin foam material (compression hardness HO, 18 kg/cnr).
One with a thickness of 1 mm and one with a thickness of 1.5 mm were used.

In addition, the cushioning material constituting the above-mentioned laminate is made of rubber elastomer chloroprene rubber (compression hardness H = 0.22 kg).
/cm2) was used. A thin plate of polyvinyl chloride resin was used as a restraining material to integrally cover the laminate of .

The weight increase of this racket was 20g.

The apparent vibration loss coefficient of this racket was measured and shown in Table 1.

As is clear from Table 1, the rackets of Examples 1 to 3 all have a higher apparent vibration loss coefficient, an extremely small impact feeling, and a better impact on hitting the ball than a blank racket without a vibration suppressor unit. It was evaluated as having a light and soft feel. In particular, rackets with implementation percentages J 2 and 3 were rated as extremely good.

[Effects of the Invention] According to the present invention, it is possible to provide a racket that has a function of extremely effectively damping the transmission of impact vibrations from the gut to the frame, shaft, and grip when a ball is hit.

With this racket, the sweet spot is enlarged, there is no unpleasant vibration or stiffness when hitting the ball, and the player can play comfortably without accumulating fatigue in his arms or elbows.

[Brief explanation of drawings]

FIG. 1 is a plan view of one example of the racket of the present invention, in which a vibration suppression unit is attached to the shaft portion;
The figure is an enlarged view of the shaft part in Fig. 1, and Fig. 3 is an enlarged view of the shaft part in Fig. 1.
2 is a perspective view showing the structure of the vibration suppressor unit used in FIG. 1. FIG. FIG. 4 is a perspective view showing another structural example of the vibration suppressor unit shown in FIG. 3. FIG. 5 is a sectional view showing an example of a method for attaching the vibration suppressor unit according to the present invention. FIGS. 6(a), 6(b), and 6(c) are sectional views showing other structural examples of the vibration suppressor unit shown in FIGS. 3 and 4. FIG. Figures 7 (a) and (b) are cross-sectional views of an example in which the vibration suppressor unit is attached to the edge of the frame at the top of the racket, and Figures 8 (a) and (b) are cross-sectional views of the vibration suppressor unit. FIG. 3 is a cross-sectional view of an example in which the unit is loaded into the frame at the top of the racket. 1: Gut 2: Frame 3: Shaft 4 Nigelip 5: Vibration suppressor unit 6
: Band 7: Vibration suppression material 8: Restraint material 9: Cushioning material 10: Hole 11: Stopper

Claims (8)

[Claims] (1) At least a portion of the members constituting the racket,
A racket characterized in that a vibration suppressing body unit is fixed, which is composed of a vibration suppressing material and a restraining material made of a material having higher strength and rigidity than the vibration suppressing material. (2) The racket according to claim (1), wherein the restraining material is made of a material having higher wear resistance than the vibration suppressing material. (3) The vibration suppression material has a vibration loss coefficient of 0 at room temperature.
2. The racket according to claim 1, wherein the racket is made of a material having a molecular weight of 0.02 or higher. (4) The vibration suppression material has a vibration loss coefficient of 0 at room temperature.
The racket according to claim 1, wherein the racket is made of a material having a grade of 0.04 or higher. (5) The racket according to claim (1), wherein the vibration suppressor unit is fixed to the racket component with a cushioning material interposed between them. (6) The cushioning material is 25% as specified in JISK6767.
Compression hardness during compression is 0.005-5.0kg/cm^2
The racket according to claim 5, wherein the racket is made of a material. (7) Claim in which the vibration suppressing material is a composite with a cushioning material (
1) The racket described. (8) The racket according to claim (1), wherein the vibration suppressor unit is a composite body of a buffer material and a restraint material.