JPH09276449A - Racket frame - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a racket frame which can be manipulated easily even for a high-level player having high swing speed, has high repulsiveness against high speed, further, easily loads spin and improves controllability as well. SOLUTION: Concerning a racket frame 1 made of fiber reinforced synthetic resin having a face part 2 forming a gut face by spreading over gut, shaft part 3 continued to the face part 2 and grip part 4 continued to the shaft part 3, when the weight is less than 260g and measured while fixing the base end of the grip part 4 and applying the load of 6kg to the top end of the racket frame vertically to the gut face, the bending warp quantity of the racket frame 1 is less than 11mm. When the load of 6kg is applied to the widest section of the face part 2 vertically to the gut face, a torsion angle around a frame axis is smaller than 2 deg., S/T is from 0.3 to 0.6 and T is less than 22mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a racket frame for hard tennis, and more particularly to a racket frame suitable for advanced players, which has a frame rigidity matching modern speed tennis.

[0002]

2. Description of the Related Art As a rigid tennis racket frame,
Those made of fiber reinforced synthetic resin are widely used. Such a fiber-reinforced synthetic resin racket frame is formed by laminating a prepreg sheet around a core material, placing the prepreg sheet in a frame-shaped cavity of a mold, and heating it (for example, JP-A-5-96030). Issue).

By the way, the conventional racket frame for advanced players is 290 when the gut (string) is stretched.
g or more (270 as racket frame before gut tension
g or more). The racket frame, which is lighter than that,
It is intended for beginners and weak players (such as women).

[0004]

The conventional racket frame for advanced players is inferior in operability because the weight after the gut is stretched is as large as 290 g or more. In particular, in recent years, the ball speed in high-level tennis tournaments has been increasing more and more, and it is disadvantageous to win a tournament with a heavy racket frame which is inferior in operability.

A racket frame that weighs less than 290 g
Conventionally designed for beginners and women, it has low frame rigidity and large bending. For this reason, if an advanced player with a large swing speed tries to hit back a high speed ball by using a conventional lightweight racket frame, it is easy to lose the momentum of the ball.

In order to improve the low rigidity of the conventional lightweight racket frame for advanced players, it is conceivable to increase the back width. However, in this case, the flexural rigidity of the face portion in the gut surface direction becomes excessively large. As a result, the contact time between the ball and the gut becomes shorter, spin is less likely to be applied to the hit ball, and the ball controllability becomes worse.

It is an object of the present invention to provide a racket frame which is easy to operate even for a high-level player having a high swing speed, has a high resilience that does not lose high speed, and is easy to spin and has good controllability. .

[0008]

A racket frame of the present invention has a face portion which extends a gut to form a gut surface, a shaft portion which is continuous with the face portion, and a grip portion which is continuous with the shaft portion. In the racket frame made of reinforced synthetic resin, the weight of the racket frame before adjusting the gut (that is, before the gut is stretched) is 260 g or less, the base end of the grip portion is fixed, and the gut surface is attached to the tip of the racket frame. The bending deflection of the racket frame is 1 when measured with a load of 6 kg in the vertical direction.
When the maximum thickness of the face portion in the direction perpendicular to the gut surface is T and the maximum thickness in the gut surface direction is S, the value of S / T is 0.3 to 0.6. The thickness T is 22 mm or less.

The racket frame of the present invention has a light weight of 260 g or less before adjusting the gut, and has a weight of 280 g or less even after the gut is stretched, and has good operability.

The racket frame of the present invention has a high rigidity in the direction perpendicular to the gut surface (deformation under a load of 6 kg is 11 mm).
Below), so it has a high resilience that does not lose to high-speed balls of advanced players.

The thickness of the face portion in the direction perpendicular to the gut surface (this thickness is usually called "back width") T is 22 mm or less, and S / T is 0.
From 3 to 0.6, the ball is held to a certain extent at the time of hitting the ball, and a proper ball contact time can be secured. This makes it easier to spin the hit ball and also provides good ball controllability.

In the present invention, the directionality of the ball is reduced by reducing the torsion angle around the frame axis to 2 degrees or less when a load of 6 kg is applied to the maximum width portion of the face portion in a direction perpendicular to the gut surface. It is stable and the surface blur is small.

[0013]

1 (a) is a front view of a racket frame 1 according to an embodiment, and FIG. 1 (b) is a sectional view taken along line BB in FIG. 1 (a). In the embodiment shown in FIG. 1, the face portion 2, the shaft portion 3 and the grip 4 are all made of fiber reinforced synthetic resin. The face portion 2 is provided with a gut insertion hole 2a, and the gut is stretched through a grommet (not shown). FIG.
As can be seen from (b), in this embodiment, the outer edge portion of the racket frame is flat.

The shaft portion 3 has a double yoke structure having a bridge 6 extending in a direction perpendicular to the axial direction of the racket frame, and the torsional rigidity of the shaft portion 3 is enhanced.

The racket frame 1 has a weight before the gut adjustment of 260 g or less, preferably 240 to 260 g, especially 240 to 250 g, and even after the gut is stretched, it is 2 g.
It is less than 80g. Because of its light weight, it is light and easy to operate, making it suitable for modern high-speed tennis.

The back width T of this racket frame 1 is 22 m.
m or less, preferably 14 to 22 mm, especially 18 to 20 m
m. Back width and width S (mm) in the cross direction and back width T
The ratio S / T with (mm) is 0.3 to 0.6, preferably 0.
4 to 0.6, especially 0.5 to 0.6.

In this way, the back width can be held small and S
By setting / T within a predetermined range, the contact time between the ball and the gut can be made appropriate, spin can be easily applied, and ball controllability can be improved.

Next, the amount of bending and bending of the racket frame will be described.

I Bending Deflection The bending deflection of this racket frame 1 is as shown in FIG. 2, in which the base end of the racket frame 1 is fixed over a range of 150 mm, and the load P of 6 kg is applied to the tip of the racket frame 1 perpendicular to the gut surface. Bending displacement W of the tip when applied
(Mm).

In the present invention, this bending deflection amount is set to 11
By using a racket frame having a rigidity of not more than mm, it is possible to achieve high resilience comparable to speed even when hitting a high speed ball with a high speed swing. If this bending deflection amount is larger than 11 mm, high repulsion cannot be obtained, and the racket frame becomes excessive during high-speed swing or when a high-speed ball is hit back, and the directionality of the ball is not stable. The bending amount is 5m
If it is smaller than m, the racket frame is too hard for an advanced player, and the shot feeling and swinging feeling are inferior. Therefore, the bending deflection amount is 5 to 11 mm, especially 7
It is preferably from 10 to 10 mm.

II Twist angle As shown in FIG. 3 (a view of the racket from the front end to the rear end), the racket frame is cantilevered and a maximum load of 6 kg is applied to the maximum width of the head in a direction perpendicular to the gut surface. The twist angle θ generated at this time is measured.

If the twist angle θ is larger than 2.0 degrees, the face surface is apt to shake when hitting a ball. If the twist angle θ is smaller than 1.0 degree, the shot feeling becomes too hard, and the impact transmitted to the hand at the time of impact becomes large. Therefore, the twist angle is 1 to 2 degrees, especially 1 to 1.
It is preferably 5 degrees.

As described above, in the present embodiment, the shaft portion has the double yoke structure to increase the torsional rigidity of the shaft portion.

The racket frame of the present invention is made of fiber reinforced synthetic resin.
Tensile elastic modulus of 15 ton / mm ² or more, especially 20 to 4
0 ton / mm ² is preferable, carbon fiber,
Boron fiber, alumina fiber, ultrafine iron wire, Ti-Si-
C-O fiber (trade name Tyranno fiber), aromatic polyamide fiber, aromatic polyester fiber, ultra-high-molecular polyethylene fiber, etc. can be used, but a type called HM graphite in terms of strength and elasticity and cost. High strength of
Highly elastic carbon fibers are preferred.

As the synthetic resin, epoxy resin, nylon and the like are preferable, but epoxy resin is preferable in terms of strength, durability and cost.

In order to manufacture the racket frame of the present invention, a plurality of prepreg sheets are laminated around a core material, which is placed in a frame-shaped cavity of a mold and heated, and a racket made of a fiber reinforced synthetic resin. A normal frame manufacturing method may be used.

The elastic modulus of the fiber reinforced synthetic resin can be changed by changing the amount and orientation of the fibers in the prepreg sheet. In addition, as shown in FIGS. 1C to 1E, a racket frame having a rounded shape may be used in which a groove is formed on the outer edge portion of the racket frame. In that case T
And S are the gut surfaces of the face portions 2 ', 2 ", 2"', the maximum thickness in the vertical direction and the maximum thickness in the gut surface direction, respectively.

[0028]

As described above, the racket frame of the present invention is lightweight and has excellent operability. Further, when used by a high-level player having a high swing speed, it is possible to obtain high repulsion comparable to a high speed ball and a high speed swing. Moreover, it is possible to hold the ball appropriately and obtain an appropriate spin imparting property. Further, in this racket frame, the directionality of the ball is stable and the fluctuation of the surface is extremely small.

[Brief description of drawings]

FIG. 1A is a front view showing a racket frame according to an embodiment, and FIG. 1B is a sectional view taken along the line BB in FIG. 1A, FIG. 1C, and FIG. Drawing and (e) figure are sectional views of the racket frame concerning another embodiment.

FIG. 2 is an explanatory diagram of measurement of bending rigidity.

FIG. 3 is an explanatory diagram of measurement of twist.

[Explanation of symbols] 1 racket frame 2 face part 3 shaft part 4 grip part

Claims (2)

[Claims] 1. A racket frame made of a fiber-reinforced synthetic resin, comprising: a face portion that extends a gut to form a gut surface; a shaft portion that extends to the face portion; and a grip portion that extends to the shaft portion. The weight of the front racket frame is 260 g or less, the base end of the grip portion is fixed, and the amount of bending deflection of the racket frame is measured when a load of 6 kg is applied to the tip of the racket frame in a direction perpendicular to the gut surface. Is 11 mm or less, and the maximum thickness in the direction perpendicular to the gut surface in the face portion is T, and the maximum thickness in the gut surface direction is S, S /
A racket frame having a T value of 0.3 to 0.6 and a thickness T of 22 mm or less. 2. The twist angle around a frame axis when a load of 6 kg is applied to a maximum width portion of the face portion in a direction perpendicular to a gut surface according to claim 1, wherein a twist angle around a frame axis is 2.0 degrees or less. And racket frame.