JPH11333029A - Racket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a racket rapidly absorbing and attenuating only shockwise vibration without loosing the function of racket such as a repelling function and a lightweight condition and alleviating the load on a user's joint as well as unpleasant feeling at the time of hitting a ball. SOLUTION: This is a racket having a shocking vibration absorbing member in its frame 2. Not less than 80% of the whole surface of the member is made as a non-contact surface to thereby enhance the absorbing efficiency of shocking vibration. The grip end of the racket and/or the top thereof are provided with the shocking vibration absorbing members to thereby reduce the reflection waves at the end of racket frame 5. Accordingly, with the addition of a light weight the shocking vibration can be absorbed and attenuated, resulting in giving less load to the joint of elbow of user.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a racket excellent in the function of absorbing shock vibration.

[0002]

2. Description of the Related Art Rackets used for tennis, badminton, squash, racquet balls, and the like require high resilience, light weight, and high durability. Or made of fiber reinforced plastic using carbon fiber or glass fiber. However, on the other hand, those using these various materials are generally inferior in impact vibration absorption performance as compared with conventional wooden ones, and have a great discomfort when hitting without a sweet spot. It causes elbow joint disorder called elbow.

[0003] In the case of a tennis racket, a rubber or resin vibration absorbing member called a "stabilizer" is commercially available for the purpose of absorbing vibration at the time of hitting a ball. However, there was almost no effect of suppressing the impact vibration of the frame, and it could not be a means to prevent tennis elbow.

Further, Japanese Patent Application Laid-Open No. 5-76621 discloses that
As a shock vibration absorbing member, measures against shock vibration using a so-called dynamic damper are disclosed, but since the dynamic damper has a structure having a mass inside a low elastic material, the cost is increased by this assembling work. For this reason, it is necessary to reduce the size of the dynamic damper in order to embed it in the frame, so that the assembling work requires skill and there is a problem that the vibration damping characteristics of the individual dynamic dampers tend to vary.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to rapidly absorb and attenuate only impact vibrations without impairing the function as a racket, such as resilience performance and weight reduction, to provide discomfort at the time of impact and to joints. An object of the present invention is to provide a racket that can reduce a burden.

[0006]

In order to solve the above-mentioned problems, in a racket according to the present invention, in a racket provided with a shock vibration absorbing member on a frame, at least 80% of the entire surface of the shock vibration absorbing member is made of another member. Is a non-contact surface.

That is, in the racket according to the present invention, the surface of the shock vibration absorbing member that is not in contact with other members is made as large as 80% or more of the entire surface, thereby greatly improving the shock vibration absorbing efficiency. Can be. Further, by disposing the shock and vibration absorbing member at an appropriate position, the reflected wave at the end of the racket frame, for example, the end on the grip side or the end on the top side of the racket frame (that is, one or both ends). And the shock vibration can be efficiently absorbed and attenuated.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with preferred embodiments. The racket according to the present invention has an 8
0% or more is configured to be a non-contact surface with other members, and effectively absorbs and attenuates shock vibrations in the shock vibration absorbing member.

If the surface of the shock vibration absorbing member that is not in contact with other members is at least 80% of the entire surface of the shock vibration absorbing member, it is possible to increase the efficiency of absorbing shock vibration, but it is more preferable. Is 90% or more, that is, in a state close to a point with another member or in a state of being in contact with a line.

[0010] It is most preferable that the impact vibration absorbing member be in direct contact with the bent tube portion and / or the grip portion constituting the racket frame. However, the contact area between the impact vibration absorbing member and the frame can be stabilized, or the replacement work can be performed. For the purpose of simplification, high durability, and the like, a member made of resin, metal, or the like may be interposed between the shock vibration absorbing member and the frame constituent member.

Further, the shock vibration absorbing member and the racket frame may be in a non-contact state when the racket is at rest. However, in this case, at least at the time of hitting, the impact vibration absorbing member and the racket frame must be in contact.

Here, the term "hit" means one second after the ball hits the gut. In a tennis racket made of fiber-reinforced plastic which is generally used at present, approximately one hour after a shock is applied to the frame. After 2 seconds, the vibration is almost attenuated, so 0.2 seconds after the ball hits the gut
More preferably, the impact vibration absorbing member and the racket come into contact within seconds.

As the material of the impact vibration absorbing member, various gel materials such as silicone gel, silicone rubber and urethane rubber and low elastic rubber materials can be used. Rate is 0.5GP
a or less, more preferably an ultra-low elastic material having a compression modulus of 0.1 GPa or less.

Further, the shock absorption rate of the shock vibration absorbing member according to the present invention is preferably 80% or more, but considering the use environment of the racket, 90% at 25 ° C.
It is more preferable to have the above-mentioned impact absorption rate.

Here, in the measurement of the shock absorption rate used in the present invention, as shown in FIG. 5, a steel ball 8 of φ25 mm and 65 g is freely dropped from a height of 100 mm, and the shock vibration absorbing member 9 is moved. This is performed by calculating from the ratio W ₁ / W ₀ of the impact load W ₀ when there is no impact load and the impact load W ₁ when there is the impact vibration absorbing member 9. The measurement of the shock absorption rate is performed in a 25 ° C. atmosphere using a shock vibration absorbing member having a thickness of 5 mm.

The loss coefficient of the shock and vibration absorbing member according to the present invention is preferably 0.3 or more in order to enhance the efficiency of vibration absorption. More preferably, it has a loss factor of 0.5 or more.

The penetration of the impact vibration absorbing member according to the present invention is preferably 40 or more, more preferably 100 or more. Here, the measurement of the penetration used in the present invention is performed by a method specified in JIS-K-2207.

Further, the impact vibration absorbing member according to the present invention comprises:
In order to reduce the reflected wave at the end, it is preferable to arrange the racket frame at a position within 20 mm from the grip end, more preferably within 10 mm.

Further, the impact / vibration absorbing member according to the present invention comprises:
In order to reduce the reflected wave at the end, it is preferable that the racket is arranged at a position within 50 mm from the top of the racket frame, more preferably within 20 mm.

The bent tube part of the racket frame is made of wood, aluminum, fiber-reinforced plastic, or the like.
Any material may be used, but it is most preferably made of fiber reinforced plastic in consideration of weight reduction, high resilience performance and the like.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below. (Example 1) A tennis racket 11 made of fiber-reinforced plastic was manufactured, in which the racket frame 2 was shaped as shown in Fig. 1 and the end of the grip portion of the racket frame 2 had the structure shown in Figs. .

That is, the racket 10 is constructed as shown in FIGS.
And the grip end of the racket frame 2 as shown in FIG.
The impact vibration absorbing member 1 is provided at a position within 8 mm from the part 11
Then, the shock vibration absorbing member 1 and the racket frame 2 (grid)
10mm contact area^Two, Shock vibration absorbing member 1
The contact area between the end cap 3 and 4 mm^TwoConfiguration
Is set to. Of the impact vibration absorbing member 1
Total surface area is 718mm ^TwoAnd therefore shock and vibration absorption
Approximately 98% of the receiving member 1 is not in contact with other members
It is.

The impact vibration absorbing member 1 was made of a silicone gel material having a compression elastic modulus of 0.37 GPa and a penetration of 53.

The shock vibration absorbing member 1 and the racket frame 2 are in direct contact with each other, and the racket frame 2 is made of a fiber reinforced plastic made of carbon fiber and epoxy resin.

When a shock is applied to the obtained racket,
FIG. 6 shows the acceleration at the grip. Table 1 shows the vibration damping ratio of the racket in the primary natural vibration.

[0026]

[Table 1]

When actually hitting such a racket,
The impact transmitted to the hand was small, and particularly the unpleasant residual vibration when hitting the ball without the sweet spot was reduced, and the burden on the elbow was small even when used for a long time. Furthermore, since the center of gravity is slightly closer to the grip, operability is good in playing volleys and the like.

(Example 2) A tennis racket was obtained in exactly the same manner as in Example 1 except that the shock vibration absorbing member was made of ultra-low elastic rubber made of urethane resin having a shock absorption rate of 90%. FIG. 7 shows the acceleration at the grip when an impact is applied to the obtained racket. Table 1 shows the vibration damping ratio of the racket in the primary natural vibration.

When actually hitting such a racket,
Similar to the racket of Example 1, the impact transmitted to the hand was small, and particularly, unpleasant residual vibration when hitting the ball without the sweet spot was reduced, and the burden on the elbow was small even after long use. In addition, since the center of gravity is slightly closer to the grip, the operability is good in playing volleys and the like.

(Example 3) A tennis racket exactly the same as that of Example 1 except that an ultra-low elastic rubber made of an ether-based polyurethane resin having a loss coefficient of 0.58 to 0.62 is used for the shock vibration absorbing member. I got FIG. 8 shows the acceleration at the grip when an impact is applied to the obtained racket. Table 1 shows the vibration damping ratio of the racket in the primary natural vibration. Further, when such a racket was actually hit, as in the case of the racket of Example 1, the impact transmitted to the hand was small, and in particular, unpleasant residual vibration when hitting the ball with the sweet spot removed was reduced, and The burden on the elbow was small even with the use of. In addition, since the center of gravity is slightly closer to the grip, the operability is good in playing volleys and the like.

(Example 4) In the racket shown in FIG. 1, a tennis racket made of a fiber-reinforced plastic was manufactured in which an impact vibration absorbing member was arranged at a position within 20 mm from a racket frame (top) 5 as shown in FIG. .

That is, the racket has a gut groove 12 in the racket frame (top) 5 portion through which the central axis 7 in the racket longitudinal direction passes, and a gut groove 12 between the first and second vertical guts in both directions from the top. Shock and vibration absorbing member 4 inside
And the contact area between the shock vibration absorbing member 4 and the top of the racket frame 5 is set to 16 mm ² , and the contact area between the shock vibration absorbing member 4 and the bumper 6 is set to 5 mm ^2. . The total surface area of each of the shock vibration absorbing members 4 is 112 mm ² , so that about 81% of the shock vibration absorbing members 4 are surfaces that are not in contact with other members.

As in the first embodiment, a silicone gel material having a compressive elasticity of 0.37 GPa was used for the shock vibration absorbing member 4.

The impact vibration absorbing member 4 and the racket frame 5 are in direct contact with each other, and the bent tube forming the racket frame 5 is made of a fiber reinforced plastic made of carbon fiber and epoxy resin.

When a shock is applied to the obtained racket,
FIG. 9 shows the acceleration at the grip. Table 1 shows the vibration damping ratio of the racket in the primary natural vibration.

When such a racket was actually tested,
Similar to the racket of Example 1, the impact transmitted to the hand was small, and particularly, unpleasant residual vibration when hitting the ball without the sweet spot was reduced, and the burden on the elbow was small even after long use. In addition, the center of gravity was slightly closer to the tip, so the moment of inertia increased, the rebound performance was good, and the sweet area was wide.

Comparative Example 1 A tennis racket was obtained in exactly the same manner as in Example 1 except that the impact vibration absorbing member was removed. FIG. 10 shows the acceleration at the grip when an impact is applied to the obtained racket. Table 1 shows the vibration damping ratio of the racket in the primary natural vibration.

When actually hitting such a racket,
Residual vibration peculiar to fiber reinforced plastic racket using thermosetting resin as matrix resin remains, especially for beginners who tend to remove sweet spots, causing a little fatigue to elbows after long use. .

[0039]

According to the racket of the present invention, the impact vibration absorbing member has a large surface which is not in contact with other members, thereby increasing the efficiency of absorbing shock vibration. , The reflected wave at the end of the racket frame can be reduced, the shock vibration can be efficiently absorbed and attenuated, and the load on the elbow joint can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view showing the entire configuration of a racket.

FIG. 2 is a perspective view of a grip end of the racket according to the present invention.

FIG. 3 is a cross-sectional view of the grip unit shown in FIG. 2;

FIG. 4 is a perspective view of a cross section near the top of the frame of the racket according to the present invention.

FIG. 5 is an explanatory diagram showing a method for measuring a shock absorption rate.

FIG. 6 is a characteristic diagram illustrating acceleration in a grip of the racket of the first embodiment.

FIG. 7 is a characteristic diagram showing acceleration in a grip of the racket of the second embodiment.

FIG. 8 is a characteristic diagram showing acceleration in a grip of the racket of the third embodiment.

FIG. 9 is a characteristic diagram illustrating acceleration in a grip of the racket of the fourth embodiment.

FIG. 10 is a diagram showing acceleration at a grip of the racket of Comparative Example 1.

[Description of Signs] 1 Impact vibration absorbing member 2 Racket frame (grip) 3 End cap 4 Impact vibration absorbing member 5 Racket frame (top) 6 Bumper 7 Racket longitudinal center axis 8 Steel ball 9 Impact vibration absorbing member 10 Racket 11 Grip end 12 gut groove

Claims (9)

[Claims] 1. A racket in which a shock vibration absorbing member is provided on a frame, wherein at least 80% of the entire surface of the shock vibration absorbing member is a surface that is not in contact with other members. 2. The compression elastic modulus of the shock vibration absorbing member is 0.5
The racket according to claim 1, wherein the racket is not more than GPa. 3. The impact absorption rate of the impact vibration absorbing member is 80%.
The racket according to claim 1 or 2, wherein: 4. The racket according to claim 1, wherein a loss coefficient of the shock vibration absorbing member is 0.3 or more. 5. The racket according to claim 1, wherein the penetration of the impact vibration absorbing member is 40 or more. 6. The racket according to claim 1, wherein the impact vibration absorbing member is disposed at a position within 20 mm from a grip end of the racket frame. 7. The racket according to claim 1, wherein the shock vibration absorbing member is arranged at a position within 50 mm in a grip direction from a top of the racket frame. 8. The racket according to claim 1, wherein at least the bent tube portion of the frame is made of fiber reinforced plastic. 9. The racket according to claim 1, wherein a vibration damping ratio in primary natural vibration is 0.005 or more.