JPH0838659A - Golf club shaft - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a golf club shaft having a constant bending rigidity distribution in a predetermined range, which is suitable for a golfer having relatively high strength and high head speed. The purpose is to provide. A golf club shaft made of fiber reinforced plastic, wherein the flexural rigidity distribution of the shaft is constant within a range of 300 to 400 mm from the butt end.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a golf club shaft having a constant flexural rigidity distribution in a predetermined range, which is suitable for a golfer having relatively high strength and high head speed.

[0002]

2. Description of the Related Art Conventionally, metal pipe shafts for golf clubs have been used among professional golfers and advanced golfers. In recent years, however, lightweight shafts for golf clubs have been demanded, and they have a specific gravity higher than that of metal. Small fiber reinforced plastic shafts are becoming popular. A shaft for a golf club made of fiber reinforced plastics, for example, a prepreg obtained by impregnating aligned carbon fibers with a thermosetting resin is wound around a mandrel which is a core,
It is manufactured by a sheet winding method in which the mandrel is drawn out after being heat-cured, or a filament winding method in which carbon fiber impregnated with a thermosetting resin is wound directly around the mandrel, and after heating and hardening the mandrel is taken out.

[0003]

However, a golf club shaft made of fiber reinforced plastics is generally lighter in weight than a golf club shaft made of a metal pipe, but it is soft and easily bent and twisted easily. Had characteristics. In particular, in the vicinity of the grip mounting portion, that is, in the portion of 300 to 400 mm from the butt end, the pipe diameter increases, but the relative thickness with respect to the pipe diameter decreases, and as a result, the vicinity of the hand feels particularly soft It was. Therefore, when a golfer with a relatively high strength uses a fiber reinforced plastic golf club shaft, the shaft bends from the vicinity of the grip mounting portion and the head delay increases, so the directionality is not stable. There was a drawback that a strong trajectory could not be obtained above.

However, if the rigidity of the shaft is increased as a whole, the flexure of the shaft is completely eliminated and the head speed is reduced. Therefore, the golf club shaft made of the fiber reinforced plastics according to the present invention does not continuously change the flexural rigidity distribution of the shaft, but at least 300 to 40 from the butt end.
The bending rigidity value is 8 to 11 × 10 ⁶ k in the range of 0 mm.
By keeping gf · mm ² constant, it is possible to provide a golf club shaft having a good directional property, which is suitable for a senior golfer who has a relatively high strength.

[0005]

A golf club shaft according to the present invention is a golf club shaft made of fiber reinforced plastic, and the flexural rigidity distribution of the shaft is constant in the range of 300 to 400 mm from the butt end. Is a shaft for a golf club. Particularly, the bending stiffness distribution is 300 to 40 from the butt end.
The bending rigidity value is 8 to 11 × 10 ⁶ k in the range of 0 mm.
It is possible to provide the most suitable shaft for a golfer having a head speed of about 40 to 50 km / sec, when it is kept constant within the range of gf · mm ² .

Here, the flexural rigidity distribution is the flexural rigidity value over the entire length of the shaft, that is, the amount of change in the product of the longitudinal elastic modulus E determined by the material of the shaft and the second moment of area I determined by the shape of the cross section of the shaft. Now say
The flexural characteristics of the shaft can be grasped by measuring the flexural rigidity distribution.

[0007]

The shaft for golf clubs according to the present invention is a shaft for golf clubs made of fiber reinforced plastic, and the flexural rigidity distribution of the shaft is 30 from the butt end.
By being configured to be constant in the range of 0 to 400 mm, for advanced players with fast head speed,
The amount of bending of the shaft on the grip side at the time of impact can be suppressed. Therefore, at the time of impact, the amount of deflection near the grip is extremely small compared to the conventional golf club shaft, while the portion of the shaft beyond the head bends to the same extent as a conventional shaft, making it firm and solid at hand. It enables a powerful swing that does not feel like it.

In particular, the bending stiffness distribution is 30 from the butt end.
Bending rigidity value of 8 to 11 × in the range of 0 to 400 mm
When it is kept constant within the range of 10 ⁶ kgf · mm ² , it is possible to provide a shaft having the most suitable bending characteristics for a golf player having a head speed of about 40 to 50 m / sec. In other words, the range where the bending stiffness distribution is constant is
When it is 300 to 400 mm or less, it is not possible to give a firm feeling near the hand, and when it is more than 300 mm, it is too hard and it becomes difficult to take a swing timing. Furthermore,
If the flexural rigidity value is 8 × 10 ⁶ kgf · mm ² or less, the bending of the shaft in the vicinity of the hand cannot be sufficiently suppressed, and conversely it is possible to set it to 11 × 10 ⁶ kgf · mm ² or more. Head speed is 40-50m /
It cannot bring about a significant effect for sec golfers.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One of the preferred embodiments of the golf club shaft according to the present invention will be described with reference to the drawings. FIG. 1 is a graph showing the bending rigidity distribution from the tip end to the butt end of the golf club shaft according to the present invention. As is clear from FIG. 1, the bending rigidity value is 10.5 × 10 ⁶ k in the region of 300 mm from the butt end to the tip end.
It is constant at gf · mm ² .

The golf club shaft according to the present invention comprises:
Aligned carbon fiber, glass fiber, aramid fiber, etc., prepreg impregnated with thermosetting resin such as epoxy resin, cut into strips, wrapped around a mandrel, which is a core metal, and after heating and curing, remove the mandrel. It is manufactured by a conventionally known technique such as a sheet winding method or a filament winding method in which a roving in which the above fibers are impregnated with a thermosetting resin is directly wound around a mandrel, which is cured by heating and then the mandrel is extracted.

Further, in the golf club shaft according to the present invention, in order to make the flexural rigidity distribution of a portion around 300 to 400 mm from the butt end constant, the winding amount of prepreg or roving is increased or the portion is wound. It is also possible to integrally laminate a reinforcing member made of a material having higher hardness and rigidity than the material forming the shaft body, such as high-strength carbon fiber or metal fiber. For example, a bias prepreg shown in FIG. 5 and a straight prepreg shown in FIG. 6 are laminated and wound around a mandrel, and although not shown, metal fine wire, aramid fiber or high strength is provided around 300 to 400 mm from the butt end. By increasing the bending rigidity by a known method such as winding a carbon fiber or the like, the bending rigidity distribution at that portion can be made constant.

FIG. 1 shows a flexural rigidity distribution from a tip end to a butt end of a golf club shaft according to the present invention, and FIG. 2 shows a flexural rigidity of a conventional golf club shaft. Distribution. As is clear from these figures, the golf club shaft according to the present invention has a constant flexural rigidity distribution from the butt end to a position approximately 300 mm, whereas the conventional golf club shaft has a butt end. The bending rigidity distribution is constant from the position to about 160 mm. In the conventional golf club shaft, the flexural rigidity distribution near the butt end is constant because the shaft shape is straight so that the grip can be easily mounted.
Therefore, when the grip is attached, the portion where the flexural rigidity distribution is constant is covered with the grip, and the flexure of the shaft is not affected at all.

FIG. 3 shows the rate of change in curvature immediately before impact when a ball is hit with a club using the golf club shaft according to the present invention, and FIG. 4 is conventionally used. It is the rate of change of the curvature of the golf club shaft immediately before the impact. As can be seen from these figures, the golf club shaft according to the present invention has a change amount of flexure in a region of 500 to 750 mm from the tip end (200 to 450 mm from the butt end) as compared with the conventional shaft. You can see that it is decreasing.

[0014]

Since the golf club shaft according to the present invention is constructed as described above, the flexural rigidity distribution of the shaft is made constant within the range of 300 to 400 mm from the butt end. For advanced players with high head speed, the amount of flexure on the grip side of the shaft at the time of impact can be suppressed. Therefore, at the time of impact, the amount of bending near the grip is extremely small compared to conventional golf club shafts,
On the other hand, the part of the shaft that is closer to the head than the head flexes to the same extent as the conventional shaft, so that a powerful swing that is firm at hand and that does not feel firmness is possible.

In particular, the bending stiffness distribution is 30 from the butt end.
8-11 × 10 ⁶ kgf in the range of 0-400 mm
・ Head speed is 4 when it is constant in the range of mm ^2.
It is possible to provide a shaft having the most suitable bending characteristics for a golf player having a speed of 0 to 50 m / sec.

[Brief description of drawings]

FIG. 1 is a graph showing a flexural rigidity distribution of a golf club shaft according to the present invention.

FIG. 2 is a graph showing a flexural rigidity distribution of a conventional golf club shaft.

FIG. 3 is a graph showing the amount of change in flexure of a golf club shaft according to the present invention immediately before impact.

FIG. 4 is a graph showing the amount of change in bending of a conventional golf club shaft immediately before impact.

FIG. 5 is a view showing a bias prepreg sheet forming a golf club shaft according to the present invention.

FIG. 6 is a view showing a straight prepreg sheet forming a golf club shaft according to the present invention.

[Explanation of symbols]

 1 butt end 2 tip end

Claims (2)

[Claims] 1. A golf club shaft made of fiber reinforced plastics, wherein the flexural rigidity distribution of the shaft is constant within a range of 300 to 400 mm from the butt end. 2. A shaft for the golf club, comprising:
The flexural rigidity distribution of the shaft is 300 to 4 from the butt end.
The bending rigidity value is 8 to 11 × 10 ^{6 in} the range of 00 mm.
The golf club shaft according to claim 1, wherein the shaft is constant within a range of kgf · mm ² .