JP2991629B2 - Golf club shaft - Google Patents

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, which is suitable for a golfer having a relatively high arm strength and a high head speed by controlling the torsional rigidity distribution of the shaft. A golf club shaft having the shaft.

[0002]

2. Description of the Related Art Conventionally, golf club shafts made of metal pipes have been used between professional golfers and advanced golfers. However, in recent years, lightweight golf club shafts have been demanded, and the specific gravity is lower than that of metal. Shafts made of small fiber reinforced plastics have become widespread. A golf club shaft made of fiber reinforced plastics is, for example, a prepreg obtained by impregnating a thermosetting resin into aligned carbon fibers is wound around a mandrel as a core metal,
It is manufactured by a sheet winding method in which a mandrel is extracted after heating and curing, or a filament winding method in which a carbon fiber impregnated with a thermosetting resin is directly wound around a mandrel, and after heating and curing, the mandrel is extracted.

[0003]

However, golf club shafts made of fiber reinforced plastics are generally lighter but softer, more flexible, and easier to twist than golf club shafts made of metal pipes. Had properties. In particular, in a region near the head mounting portion from near 600 mm from the tip end, the torsional rigidity GI sharply decreases as the pipe diameter decreases, and as a result, the golf club shaft is particularly likely to twist near the head mounting portion. Was. This tendency is particularly remarkable when a relatively advanced golfer uses a golf club shaft made of fiber reinforced plastics, and the shaft is twisted from the vicinity of the head mounting portion, and the angle of the head at impact is reduced. There was a drawback that it opened and the directionality was unstable.

On the other hand, if the torsional rigidity of the shaft is increased as a whole, there is a disadvantage that the diameter of the grip portion of the shaft becomes large, it is difficult to grasp, and the weight of the shaft itself increases. In addition, costs increase due to an increase in the number of materials. Therefore, the golf club shaft made of the fiber-reinforced plastics according to the present invention has a region that greatly affects the torsion near the head mounting portion of the shaft,
That is, by increasing the torsional stiffness in the region from the vicinity of 600 mm from the tip end to the head mounting portion where the torsional moment of the shaft sharply decreases, it is lightweight and
An object of the present invention is to provide a golf club shaft with good directivity suitable for a senior golfer having relatively strong strength.

[0005]

A golf club shaft according to the present invention is a golf club shaft made of fiber reinforced plastics, which has a torsional rigidity GI (× 10 ⁶ kgf · mm ² ) and a tip. A golf club shaft characterized in that a distance X (mm) from an end has a torsional rigidity distribution satisfying a relationship defined by the following equation. GI> ΣA _i × X ＾ i (i = 0 to 4) i = 0 A ₀ = −1.328E + 5 i = 1 A ₁ = 2.456E + 4 i = 2 A ₂ = −1.164E + 2 i = 3 A ₃ = _{2.698E-1 i = 4 A 4} = -1.807E-4

Further, in the golf club shaft, the distance X ≦ 600 (m) from the tip end, which most affects the opening of the face surface at the time of impact of the head.
m), the torsional rigidity GI (×
10 ⁶ kgf · mm ² ) and the distance X (m) from the tip end
m) is a golf club shaft characterized by having a relationship defined by the following equation. GI> ΣA _i × X ＾ i (i = 0 to 4) i = 0 A ₀ = −1.328E + 5 i = 1 A ₁ = 2.456E + 4 i = 2 A ₂ = −1.164E + 2 i = 3 A ₃ = _{2.698E-1 i = 4 A 4} = -1.807E-4

[0007] Here, the torsional rigidity GI i.e. over the entire length of the shaft and the torsional rigidity distribution, the shear modulus G which is determined by the material of the shaft (kgf / c m ^2), section two determined by the shape of the cross section of the shaft primary polar moment I
(C m ⁴⁾ lead to a significant refers to variation of the product of, by measuring the torsional rigidity distribution, in which can grasp the characteristics of torsion of the shaft.

[0008]

The golf club shaft according to the present invention is a golf club shaft made of fiber reinforced plastics, and has a torsion characteristic satisfying the above relational expression. In addition, the torsion of the shaft at the time of impact can be effectively suppressed. In particular, when the torsional rigidity value GI is restricted to a range satisfying the above relational expression within a range of 600 mm or less from the tip end, the head speed becomes 45 to 55.
For golfers of the order of (m / s), the torsion of the shaft can be suppressed most effectively.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One preferred embodiment of a golf club shaft according to the present invention will be described with reference to the drawings. The product of the present invention
The torsional rigidity GI of the shaft (× 10 ⁶ kgf · mm
² ) and the distance X (mm) from the chip end is GI> ΣA _i × X ＾ i (i = 0 to 4) i = 0 A ₀ = −1.328E + 5 i = 1 A ₁ = 2.456E + 4 i = 2 A ₂ = −1.164E + 2 i = 3 A ₃ = 2.698E−1 i = 4 A ₄ is configured to have a torsional stiffness distribution that satisfies the following relationship. FIG. 1 is a graph showing the distribution of torsional rigidity from the tip end to the butt end of the golf club shaft according to the present invention, the conventional metal pipe shaft, and the conventional low torque fiber reinforced plastics. When the equation is shown in a graph, it almost matches the graph of FIG. 1 relating to the golf club shaft according to the present invention. As shown in FIG. 1, the golf club shaft according to the present invention has a higher torsional rigidity in the range from the tip end to about 600 mm as compared with a conventional metal pipe shaft or a conventional low torque fiber reinforced plastic shaft. It is a shaft for golf clubs, characterized in that:

[0010] The golf club shaft according to the present invention comprises:
Pre-preg prepared by impregnating thermosetting resin such as epoxy resin into aligned carbon fiber, glass fiber, aramid fiber, etc., is cut into a substantially strip shape, wound around a mandrel as a core metal, heated and cured, and then the mandrel is removed. It is manufactured by a conventionally known technique such as a sheet winding method or a filament winding method in which a roving obtained by impregnating a thermosetting resin into the fiber is directly wound around a mandrel, heated and cured, and then the mandrel is extracted.

Further, in the golf club shaft according to the present invention, in order to increase the torsional rigidity distribution at a position near 600 mm from the tip end, the winding amount of the prepreg or roving is increased at the position, or the strength is increased at the position. It is also possible to laminate and integrate a reinforcing member made of a material having higher hardness and rigidity than the material forming the shaft body, such as carbon fiber or metal fiber. For example, in the prepreg of the bias layer of the highly elastic carbon fiber having the shape shown in FIG. 2 and the prepreg of the straight layer shown in FIG. 3, a bending point is provided at an arbitrary position of 600 mm or less from the chip end in the longitudinal direction. By laminating and winding the object around the mandrel, the torsional rigidity at a position near 600 mm from the tip end can be increased.

FIG. 4 shows head speeds of 50 m / s and 40 m / s for a golf club equipped with a golf club shaft according to the present invention, a conventional metal pipe shaft and a conventional low torque fiber reinforced plastic shaft. It shows the torsion angle of the shaft at the time of impact when the ball is set and hit. As is apparent from this figure, the golf club shaft according to the present invention, the conventional metal pipe golf club shaft, and the conventional low torque fiber reinforced plastic golf club shaft hit a ball at a head speed of 40 m / s. It can be seen that the torsional angles at the time of impact are almost the same. On the other hand, comparing the torsion angle at impact when hitting a ball at a head speed of 50 m / s, the torsion angle of the golf club shaft according to the present invention is compared with the torsion angle of the conventional golf club shaft. It can be seen that the twist angle from the tip end to around 600 mm is significantly reduced.

[0013]

The golf club shaft according to the present invention has a torsional rigidity distribution that satisfies the above relational expression, so that an advanced player with a high head speed can effectively suppress the torsion of the shaft at the time of impact. be able to. In particular, when the torsional rigidity distribution is restricted to a range satisfying the above relational expression within a range of 600 mm or less from the tip end, the head speed becomes 45 to 55.
For golfers of the order of (m / s), the torsion of the shaft can be suppressed most effectively. Therefore, for an advanced player having a relatively high head speed, when hitting a ball with a golf club using the golf club shaft according to the present invention, the torsion of the shaft near the head mounting portion at the moment of impact is reduced, The face surface can be prevented from opening, and the effect of stabilizing the directionality of the hit ball is achieved.

Further, in the golf club shaft according to the present invention, the range of 600 mm or more from the tip end, which hardly affects the torsion of the shaft near the head mounting portion, is a conventional metal pipe golf club shaft or low torque. The ball has the same torsional rigidity and outer diameter as the fiber reinforced plastic golf club shaft, and the ball feels the same as before, without making the grip too thick and difficult to grasp, and without feeling hard near the grip. It has the effect of being able to do so.

[Brief description of the drawings]

FIG. 1 is a graph showing torsional rigidity distribution from the tip end to the butt end of a golf club shaft according to the present invention, a conventional metal pipe golf club shaft, and a conventional low torque fiber reinforced plastic golf club shaft. .

FIG. 2 is a plan view of a bias layer prepreg used for a golf club shaft according to the present invention.

FIG. 3 is a plan view of a straight layer prepreg used for a golf club shaft according to the present invention and a diagram showing a comparison with a conventional prepreg.

FIG. 4 is a graph showing the distribution of torsional angles at impact of the golf club shaft according to the present invention, the conventional metal pipe golf club shaft, and the conventional low torque fiber reinforced plastic golf club shaft.

Claims (2)

(57) [Claims] 1. A golf club shaft made of fiber reinforced plastics, wherein the shaft has a torsional rigidity G.
I (× 10 ⁶ kgf · mm ² ) and distance X from tip end
(Mm) having a torsional rigidity distribution satisfying a relationship defined by the following formula: GI> ΣA _i × X ＾ i (i = 0 to 4) i = 0 A ₀ = −1.328E + 5 i = 1 A ₁ = 2.456E + 4 i = 2 A ₂ = −1.164E + 2 i = 3 A ₃ = _{2.698E-1 i = 4 A 4} = -1.807E-4 2. The golf club shaft,
The torsional rigidity (× 10 ⁶ kgf · mm ² ) of the shaft and the distance X (mm) from the tip end are X ≦ 600 (mm).
2. The golf club shaft according to claim 1, wherein the torsional rigidity distribution satisfies a relationship defined by the following formula in a region of (1). GI> ΣA _i × X ＾ i (i = 0 to 4) i = 0 A ₀ = −1.328E + 5 i = 1 A ₁ = 2.456E + 4 i = 2 A ₂ = −1.164E + 2 i = 3 A ₃ = _{2.698E-1 i = 4 A 4} = -1.807E-4