JP2000317022A - Golf club shaft, its production and apparatus for production therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a golf club shaft which is light in weight, is high in rigidity and repulsiveness and is good in the directivity of a hit ball as well. SOLUTION: The cross-sectional shape of a hollow part 12 in a direction orthogonal with the longitudinal direction of the hollow golf club shaft 10 reinforced with carbon fibers 14, etc. has a flat portion formed to a polygonal shape, etc., over a prescribed range. Further, ribs for reinforcement may be formed in the angle parts on the inside wall surface of the hollow part 12 along their angles.

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 reinforced with carbon fibers and the like, and a method and an apparatus for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as disclosed in Japanese Patent Application Laid-Open No. 9-141754, a sheet-shaped prepreg having carbon fibers in a soft resin is wound around a mandrel as a core metal. This was set in a mold to cure the resin, and then the mandrel was removed to form a hollow carbon shaft. This prepreg was wound around a mandrel over a plurality of layers having carbon fibers and metal fibers to form a golf club shaft having desired thickness, strength and torque. This golf club shaft was hollow, and the cross-sectional shape of the hollow portion was circular.

[0003]

At present, it is desired that golf clubs be lightweight and have good hitting direction. A so-called carbon shaft also greatly contributes to weight reduction. The resilience was contradictory and the weight reduction was limited. Also, the degree of bending of the golf club varies depending on the user's preference and head speed, and various golf shafts from so-called hand tone to tip tone have been provided. The bending stiffness was contradictory.

The present invention has been made in view of the above-mentioned problems of the prior art, and is a golf club shaft which is lightweight, has high rigidity and elasticity, and has good hitting direction, and a method and a method for manufacturing the same. It is intended to provide a device.

[0005]

SUMMARY OF THE INVENTION A golf club shaft according to the present invention is a fiber reinforced hollow golf club shaft, which is provided on at least a part of a hollow inner wall surface in a direction perpendicular to the longitudinal direction. A plane is formed along the plane. In addition, the hollow golf club shaft has a polygonal cross-sectional shape in a direction orthogonal to the longitudinal direction.

Further, at the corner of the inner wall surface of the hollow portion,
This is a golf club shaft having reinforcing ribs formed along its corners.

[0007] The golf club shaft of the present invention further comprises:
The cross section of the hollow portion in a direction orthogonal to the longitudinal direction is formed in a substantially elliptical shape including an elliptical shape. The major axis of the oval is formed, for example, in a direction parallel to the leading edge of the golf club head.

According to the present invention, in a method of manufacturing a hollow golf club shaft reinforced with a fiber, a mandrel having a taper in a longitudinal direction is provided, and a plurality of mandrels are provided on a side surface over a predetermined length of at least a part of the mandrel. A method of manufacturing a golf club shaft, wherein a flat surface is formed, and a fiber reinforced resin is wound around a peripheral surface of the mandrel including a portion where the flat surface is formed. It is.

The present invention also relates to an apparatus for manufacturing a fiber reinforced hollow golf club shaft, comprising a mandrel having a taper in a longitudinal direction, wherein a plurality of mandrels are provided on a side surface over a predetermined length of at least a part of the mandrel. This is a manufacturing apparatus for a golf club shaft having a flat surface.
This mandrel has a portion whose cross section in a direction perpendicular to the longitudinal direction is formed in a polygonal shape. Further, the mandrel has a polygonal cross section in a direction orthogonal to the longitudinal direction over about half or more from a portion having a large diameter to a portion having a small diameter.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 show a golf club shaft 10 according to the first embodiment. In FIGS. 1 and 3, the thickness is emphasized with respect to the length for schematic display. The golf club shaft 10 of this embodiment includes a plurality of resin layers 16, 18, 20.22 in which a hollow portion 12 is formed and reinforced by carbon fibers 14 or the like. The resin layers 16 and 18 are formed by winding the carbon fibers 14 in a direction crossing each other and obliquely to the longitudinal direction of the shaft. The resin layers 20 and 22 are layers in which reinforcing fibers such as carbon fibers 14 are arranged in the longitudinal direction of the shaft.
Is configured.

The cross section of the inner surface of the hollow portion 12 of the golf club shaft 10 in a direction perpendicular to the longitudinal direction is formed in a regular dodecagonal shape as shown in FIG. FIG. 2 shows only the oblique layer 19 and the straight layer 23 for simplification. Further, the reinforcing fibers are preferably carbon fibers 14 in view of the relationship between weight and strength,
It is possible to use appropriate fibers at appropriate densities,
Other than carbon fibers, metal fibers, silicon carbide fibers, alumina fibers, boron fibers, potassium titanate fibers, and the like can be used.

The golf club shaft 10 of this embodiment
First, a mandrel 30 as a core metal as shown in FIG. 3 is formed into a shape tapered in the longitudinal direction and formed into a regular dodecagonal shape over a predetermined range in the longitudinal direction. I do. This dodecagonal corner 3
The length of 2 is set according to the magnitude of the torque of the golf club shaft 10 to be manufactured and the degree of bending, and at least a half of the golf club shaft from the hand portion to the tip portion is the square portion 32. Is preferred. The mandrel 30 having the regular dodecagonal square portion 32 is manufactured by an NC machine tool.

First, using a mandrel 30 having a regular dodecagonal angular portion 32, a prepreg constituting the oblique layer 19 is separated via a release layer (not shown) into a mandrel 30.
Wrap around. The prepreg is a sheet-like material made of a resin such as an epoxy resin, a polyester resin, a silicone resin, a polyurethane resin, a phenol resin, a urea resin, and a melamine resin, and the resin is impregnated between carbon fibers 14. The carbon fibers 14 are arranged at a predetermined angle with respect to the longitudinal direction of the shaft 10, and are wound around a mandrel while the prepreg is soft. Cross layer 19
After winding the resin layers 16 and 18 around the mandrel 30,
Further, the prepreg constituting the straight layer 23 is wound around the mandrel 30, and the resin layers 20 and 22 are wrapped around the oblique layer 1.
Similarly, it winds around the mandrel where 9 was formed.

In the mandrel 30, the prepreg is securely adhered to the angular portion 32, and is put into a mold or the like and molded so that the surface becomes circular, and the resin layers 16, 18, 20, 2 are formed.
2 is cured. Then, polish the surface of the shaft,
Pull out the mandrel. Further, the head 24 is fixed to the tip of the shaft 10 by performing a predetermined coating or the like.

[0015] Golf club shaft 10 of this embodiment
According to this, the shape of the inner wall surface of the fiber-reinforced resin layer 16 is formed in a regular dodecagon, and the rigidity of the shaft is higher even with the same weight compared with a hollow shaft having a circular cross section due to the plane and the corner, and the elasticity is higher. It is also highly likely to develop. This is because the inner wall surface is formed in a regular dodecagon, so that
This is because a skeletal structure is formed in FIG. In addition, a golf club shaft having high flexibility, high elasticity, and a light weight can be formed.

Further, according to the golf club shaft manufacturing method and apparatus of this embodiment, a lightweight and highly resilient golf club shaft can be easily manufactured with high quality. Further, by changing the mandrel, a golf club shaft having a polygonal inner wall surface at a desired position can be easily formed.

Next, a second embodiment of the golf club shaft of the present invention will be described with reference to FIG. Here, the same members as those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted. In this embodiment, ribs 30 for reinforcement are formed at the corners of the hollow portion 12 along the longitudinal direction. The ribs 30 for reinforcement may be formed in advance by forming concave grooves in the corners of the peripheral surface of the mandrel 30 of the above embodiment.

The golf club shaft 10 of this embodiment
According to the method described above, the ribs 30 are formed at the corners of the inner wall surface of the hollow portion 12 so that the shaft 10 can be slightly increased in weight.
Can greatly increase the rigidity.

Next, a third embodiment of the golf club shaft of the present invention will be described with reference to FIG. Here, the same members as those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted. In this embodiment, the cross-sectional shape of the hollow portion 12 is elliptical. The major axis of the ellipse is formed, for example, in a direction parallel to the direction in which the golf club head 24 projects.

The golf club shaft 10 of this embodiment
According to this, since the shape of the hollow portion 12 is elliptical, the rigidity of the shaft differs in the direction of the major axis and the minor axis of the ellipse, and the rigidity in a desired direction can be formed higher. For example, the leading edge 34 of the golf club head 24
And by making the major axis of the elliptical cross section of the hollow portion parallel,
The rigidity in the long axis direction increases, and the rigidity in the short axis direction decreases.

Further, in the golf club shaft 10 of this embodiment, as shown in FIG. 7, the inner wall surface of the hollow portion 12 is formed in a substantially elliptical shape such as an ellipse. It may be formed in a polygonal shape. According to this, a golf club head having high rigidity in a desired direction can be further formed. Also in this case, reinforcing ribs may be formed at the corners of the inner wall surface of the polygon.

The golf club shaft of the present invention is
The cross section of the hollow portion may be any shape other than a perfect circle, and one or more elongated surfaces may be formed along the longitudinal direction. Any shape may be used as long as a flat portion or the like is formed on the hollow inner wall surface of the golf club shaft to increase the rigidity, or the bending degree or the kick point can be brought to an appropriate position. Further, any number may be used as long as the rigidity of the shaft can be changed, and the number of corners of the polygonal cross section can be appropriately selected, and preferably is appropriately selected from hexagons to hexagons. Further, an elliptical shape can be appropriately selected, and the ellipse mentioned here includes an ellipse. Further, the cross-sectional shape of the hollow portion may be changed along the longitudinal direction of the shaft, or a polygonal or elliptical shape may be formed midway from the hollow portion having a circular cross section.

[0023]

According to the golf club shaft of the present invention and the method and apparatus for manufacturing the same, only by changing the cross-sectional shape of the hollow portion of the hollow shaft of the golf club shaft,
You can increase or change the rigidity of the shaft,
A golf club shaft having a desired elasticity while suppressing an increase in weight can be provided.

[Brief description of the drawings]

FIG. 1 is a partially broken perspective view of a golf club shaft according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the golf club shaft according to the first embodiment of the present invention.

FIG. 3 is a front view of a mandrel for manufacturing the golf club shaft according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view of a corner portion of a mandrel for manufacturing the golf club shaft according to the first embodiment of the present invention.

FIG. 5 is a cross-sectional view of a golf club shaft according to a second embodiment of the present invention.

FIG. 6 is a cross-sectional view of a golf club shaft according to a third embodiment of the present invention.

FIG. 7 is a cross-sectional view of another golf club shaft according to the fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Golf club shaft 12 Hollow part 14 Carbon fiber 16, 18, 20, 22 Resin layer 19 Oblique layer 23 Straight layer

Claims (8)

[Claims] 1. A golf club shaft comprising a fiber-reinforced hollow golf club, wherein a flat surface is formed along at least a part of an inner wall surface of the hollow portion in a direction orthogonal to the longitudinal direction. Club shaft. 2. The golf club shaft according to claim 1, wherein the inner wall surface of the hollow portion has a polygonal cross section in a direction orthogonal to a longitudinal direction. 3. The golf club shaft according to claim 1, wherein a reinforcing rib is formed at a corner of the inner wall surface of the hollow portion along the corner. 4. A golf club shaft in which a hollow golf club shaft reinforced with a fiber has a cross section of a hollow portion in a direction orthogonal to a longitudinal direction formed in a substantially oval shape. 5. A method of manufacturing a fiber reinforced hollow golf club shaft, comprising: providing a mandrel having a taper in a longitudinal direction, and forming a plurality of planes on side surfaces over a predetermined length of at least a part of the mandrel. A method of manufacturing a golf club shaft, characterized in that a fiber reinforced resin is wound around a peripheral surface of the mandrel including a portion where the flat surface is formed to be molded. 6. A manufacturing apparatus for a fiber reinforced hollow golf club shaft, comprising a mandrel having a taper in a longitudinal direction, wherein a plurality of flat surfaces are formed on a side surface over a predetermined length of at least a part of the mandrel. An apparatus for manufacturing a golf club shaft, comprising: 7. The golf club shaft manufacturing apparatus according to claim 6, wherein the mandrel has a portion having a polygonal cross section in a direction perpendicular to the longitudinal direction. 8. The mandrel has a polygonal cross section in a direction perpendicular to the longitudinal direction over about half or more from a portion having a large diameter to a portion having a small diameter. The manufacturing apparatus of the golf club shaft according to the above.