JP2003052875A - Golf club shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate directionality of physical properties, and to improve strength of a shaft by eliminating irregularity of the physical properties such as strength and rigidity in the periphery (the circumferential direction) of the shaft. SOLUTION: This fiber reinforced resin golf club shaft is composed of a laminated body of fiber reinforced prepregs, and has a prepreg group composed of four fiber reinforced prepregs having the same structure in the fiber reinforced prepregs. The respective fiber reinforced prepregs 27 to 30 of the prepreg group are laminated so that winding starting positions 27a to 30a of four places of the respective fiber reinforced prepregs 27 to 30 become the respective apexes of an equilateral quadrangle (a square) in a shaft cross section when winding the four respective fiber reinforced prepregs 27 to 30 of the prepreg group around the shaft.

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, and more particularly, to a golf club shaft made of fiber reinforced resin with improved variations in shaft strength and rigidity around the shaft axis.

[0002]

2. Description of the Related Art Golf club shafts are mainly fiber reinforced such as an angle layer having reinforcing fibers at an angle with respect to the shaft axis, a straight layer parallel to the axis, and a hoop layer having an angle of 90 ° with respect to the axis. It consists of prepreg.
In each layer, a plurality of types of prepregs having different tensile elastic moduli of reinforcing fibers may be used, or the length of the prepreg may be changed to partially reinforce.Golf club shafts using these prepreg sheets have various designs. Has been done.

For example, the TIP (head) side and the BUTT
When using a prepreg with a different number of turns on the (grip) side, simply adjust the number of turns at the TIP end and the BUTT end to the mandrel diameter, and cut the prepreg linearly in the middle to form a single prepreg sheet. It is common that it is wound only by itself. In addition, TIP end and BU
The same is true when there are several different numbers of turns between the TT ends.

Further, in Japanese Patent Laid-Open No. 11-70197, in order to prevent the strength of the shaft from decreasing and the strength from varying,
A golf club has been proposed in which the thickness of the prepreg sheet constituting the oblique fiber layer, the number of windings, and the initial winding position are adjusted.

[0005]

However, when only one prepreg is used in the above-described design in which the number of turns on the TIP side is different from that on the BUTT side, the TIP side and the BUTT side are evenly distributed in the vicinity of the winding start position of the prepreg. Although there is a prepreg, the length of the prepreg in the shaft axial direction gradually decreases as it is wound. At this time, since the prepreg distribution becomes non-uniform,
There is a problem in that the rigidity and strength also change with the change in the existing state of the prepreg around the shaft axis (circumferential direction).

Further, in the golf club disclosed in Japanese Patent Laid-Open No. 11-70197, the initial winding position is merely shifted in the circumferential direction. Therefore, depending on how the prepreg is displaced, the thickness partially increases in the circumferential direction of the shaft. Therefore, there is a problem in that strength and physical properties around the shaft axis (circumferential direction) vary, and improvement of the shaft strength is insufficient.

Furthermore, when the number of plies (number of turns) is large,
If you wind with one prepreg sheet, air may easily enter between the sheets and the strength of the shaft may decrease, the rigidity may change, and there may be a deviation in the axial direction of the shaft, making it difficult to manufacture as designed. is there. Further, when the shaft surface is polished after curing, if the prepreg sheet is thick, a step may be formed at the end of winding, so that uneven polishing may occur.

As described above, conventionally, regarding the winding position of the prepreg and the number of windings, the target physical properties of the shaft,
It depends on the manufacturing cost, etc., and is not taken into consideration in terms of uniform strength and rigidity around the shaft axis (circumferential direction).

The present invention has been made in view of the above problems, and eliminates variations in physical properties such as strength and rigidity around the shaft axis (circumferential direction), eliminates directionality of physical properties, and improves shaft strength. It is an object to provide a golf club shaft.

[0010]

In order to solve the above problems, the present invention provides a golf club shaft made of a fiber reinforced resin comprising a laminate of fiber reinforced prepregs, which has the same structure among the fiber reinforced prepregs. Some n sheets (n ≧ 3:
n is an integer) prepreg group consisting of fiber reinforced prepregs, and n winding start positions of each fiber reinforced prepreg when n fiber reinforced prepregs of the prepreg group are wound around the shaft axis in a shaft cross section. Provided is a golf club shaft, characterized in that each fiber-reinforced prepreg of the above prepreg group is laminated so as to have each vertex of a regular n-sided polygon.

As described above, by defining the winding positions of n fiber-reinforced prepregs having the same structure, it is possible to eliminate the directionality of physical properties around the shaft axis. Specifically, all n fiber-reinforced prepregs belonging to the same prepreg group have the same shape (length, thickness, etc.), material (fiber, resin type, prepreg basis weight, etc.) and the like. Therefore, if the winding start positions of the prepreg are evenly arranged around the shaft axis, the entire prepreg including the winding end position is necessarily arranged evenly around the shaft. Therefore, the prepreg has little variation at any position in the axial direction of the shaft and is laminated almost uniformly in the circumferential direction, so that variation in shaft strength and rigidity can be suppressed.

That is, in the golf club shaft of the present invention, instead of winding a large number of large fiber reinforced prepregs and winding them, the fiber reinforced prepregs are divided into n sheets so that they can be evenly arranged around the shaft axis. You are doing it. At this time, in order to make uniform arrangement easy,
The winding start position of each prepreg of the n prepreg group is set so as to form a vertex of a regular n-sided polygon (n ≧ 3: n is an integer) in the cross-sectional view of the shaft.

The value of n in the regular n-gon is 3 ≦ n ≦ 16,
Preferably, 3 ≦ n ≦ 8, and the optimum number is n = 3. The above range is set because when n is smaller than 3, the dispersion of the physical properties becomes large in the axial direction (circumferential direction). On the other hand, if it is larger than 16, the number of prepregs is too large and it takes a long time to wind.

Further, in the golf club shaft of the present invention, at least one set of prepreg groups may be present and laminated as described above. However, a plurality of prepreg groups are provided, and each prepreg group has the above-mentioned structure. It may be laminated as described above.

It is preferable that the total number of turns on the BUTT side and / or the total number of turns on the TIP side of each fiber-reinforced prepreg of the prepreg group is a non-integer. TIP
If the total number of turns on the side or BUTT is a non-integer,
When the prepregs of the prepreg group are continuously laminated in the circumferential direction of the shaft, there is always an extra portion in the prepreg because it is not an integral number of windings, and the directionality tends to vary. Therefore, in the case of such a non-integer, the arrangement of equalized prepregs forming the apexes of a regular n-sided polygon of the present invention is particularly effective, and variations in shaft strength and rigidity around the shaft axis are reduced. can do.

It is preferable that the fiber reinforced prepregs in the prepreg group have different numbers of turns on the BUTT side and the TIP side. If the number of turns is different on the TIP side and the BUTT side due to reasons such as changing the shaft rigidity, for example, if the BUTT end has 3 plies and the TIP end has 2 plies, then the BUTT end and the TIP end will each have an integer number of turns. However, at the position between the BUTT end and the TIP end,
Most of the parts are non-integer plies. In such a non-integer ply, the wall thickness varies in the circumferential direction, and the flex or the like also varies in the circumferential direction. Therefore, the effect of the uniform arrangement of the n prepregs of the present invention, which is set so as to divide the prepreg and start winding uniformly as a prepreg group, is particularly effective.

It is preferable that each fiber-reinforced prepreg of the prepreg group is a straight layer in which reinforcing fibers are parallel to the axial direction of the shaft. The straight layer is
In particular, since the fiber-reinforced prepreg of the prepreg group is a straight layer, the effect of improving the shaft rigidity and strength can be further enhanced, since it greatly contributes to the directionality. Needless to say, the prepreg group may be an angle layer or a hoop layer.

The fiber-reinforced prepreg of the prepreg group is preferably arranged within a range of 50% or less of the shaft total length from the TIP end of the shaft or / and a range of 50% or less of the shaft total length from the BUTT end of the shaft. Specifically, the range from the TIP end of the shaft to 50% or less of the total length of the shaft, preferably 40% or less, and more preferably 30% or less. The optimum range is 20% or more and 30% or less of the total length of the shaft from the TIP end. Since the specified range is a portion where the head is close and is improved immediately before the impact, it is possible to improve the feel at the time of hitting and the flight distance by eliminating the variation in the directionality of this portion. Further, the range from the BUTT end of the shaft to 50% or less of the total length of the shaft, preferably 40% or less, and more preferably 30% or less. The optimum range is 20% or more and 30% or less of the entire shaft length from the BUTT end. The above specified range is the part where the player can feel the best bending by the force applied during the swing, so by eliminating the variation of the directionality of this part, the feel at the time of hitting the ball can be eliminated. The stability of the ring and the hit ball can also be improved.

The width of the fiber-reinforced prepreg of the above prepreg group (the length in the circumferential direction of the shaft) is 25 mm or more 2
The length is preferably 00 mm or less, more preferably 30 mm or more and 150 mm or less. The reason for setting the above range is that if it is less than 25 mm, the number of windings increases, which is time-consuming, and if one winding cannot be performed, a step may be formed and the strength may decrease. On the other hand, if it is larger than 200 mm, the number of winding layers is large, and air may enter or wrinkles between the layers.

The thickness of the fiber-reinforced prepreg of the prepreg group is 0.01 mm or more and 0.20 mm or less, preferably 0.04 mm or more and 0.15 mm or less. The reason for setting the above range is that if it is less than 0.01 mm, wrinkles are likely to occur during winding and it becomes difficult to mold. On the other hand, if it is larger than 0.20 mm, the step difference between the layers may be large and the strength may be low.

The length of the fiber reinforced prepreg of the prepreg group is 50 mm or more and 1200 mm or less, preferably 10 mm.
It is preferable that the length is 0 mm or more and 1200 mm or less. The above range is set because the effect of the present invention on the shaft performance is small when the length is shorter than 50 mm. Meanwhile, 1200
This is because if the length is longer than mm, an appropriate length cannot be obtained as the shaft.

The fiber-reinforced prepreg of the above prepreg group is the innermost layer of the prepreg laminate, or
It is preferably laminated on the outermost layer. The innermost layer and outermost layer are
This is because the strain is large and the influence on the strength is large.

The value of the tensile elastic modulus of the reinforcing fibers of the fiber-reinforced prepreg of the prepreg group is preferably 5000 kgf / mm ² or more and 80000 kgf / mm ² or less. This makes it possible to obtain appropriate strength and rigidity as a golf club shaft.

The shape of the fiber reinforced prepreg of the above prepreg group may be such that the number of windings on the TIP side and the BUTT side are different, and specifically, it may be a triangle, a quadrangle (trapezoid, etc.), or another polygonal shape. It can have various shapes. The size of the fiber reinforced prepreg may be such that the fiber reinforced prepreg is wound over the entire length of the shaft, or may be partially wound so as to reinforce the front end or the rear end of the shaft.

As the resin used for the fiber reinforced resin,
Examples thereof include thermosetting resins and thermoplastic resins. From the viewpoint of strength and rigidity, thermosetting resins are preferable, and epoxy resins are particularly preferable.

As the thermosetting resin, an epoxy resin,
Examples thereof include unsaturated polyester resins (vinyl ester resins), phenol resins, melamine resins, urea resins, diallyl phthalate resins, polyurethane resins, polyimide resins and silicon resins.

As the thermoplastic resin, a polyamide resin,
Saturated polyester resin, polycarbonate resin, A
Examples thereof include BS resin, polyvinyl chloride resin, polyacetal resin, polystyrene resin, polyethylene resin, polyvinyl acetate resin, AS resin, methacrylic resin, polypropylene resin and fluororesin.

As the reinforcing fibers used in the fiber-reinforced resin, fibers generally used as high-performance reinforcing fibers can be used. Although lightweight and high-strength carbon fiber is preferable, in addition to carbon fiber, for example, graphite fiber, aramid fiber, silicon carbide fiber, alumina fiber, boron fiber, glass fiber, aromatic polyamide fiber, aromatic polyester fiber, Ultra high molecular weight polyethylene fibers and the like can be mentioned. Alternatively, metal fibers may be used. Carbon fiber is preferable because it is lightweight and has high strength. These reinforcing fibers may be either long fibers or short fibers, and two or more kinds of these fibers may be mixed and used. The shape and arrangement of the reinforcing fibers are not limited, and any shape and arrangement such as a single direction, a random direction, a sheet shape, a mat shape, a woven (cloth) shape, and a braided shape can be used.

[0029]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a golf club shaft according to a first embodiment of the present invention. The shaft 1 is made of a laminated body of fiber reinforced prepregs, and a head 2 is provided at a tip on a small diameter side.
Is attached, and the grip 3 is attached to the large diameter end side. The shaft 1 has a total length of 1170 mm and a shaft weight of 50 g.

In the shaft 1, the fiber-reinforced prepregs 21 to 30 shown in FIG. 2 are wound around a core metal (not shown) from the inner peripheral side and laminated. Fiber reinforced prepreg 21-2
In No. 6, the mandrel is set to 1ply (once wound) on both the TIP side and the BUTT side to configure the entire shaft length (prepreg length 1195m.
m). The four fiber-reinforced prepregs 27 to 30 serve as a tip (TIP side) reinforcing layer (prepreg length 300 m
m) and 1ply on the large side, and one prepreg group 10 having the same structure in material and shape is formed. As shown in FIG. 3, when winding the fiber reinforced prepregs 27 to 30 in the shaft axial direction (circumferential direction), the n winding start positions of the fiber reinforced prepregs 27 to 30 are regular n-sided in the shaft cross section. Fiber-reinforced prepregs 27 to 30 are laminated so as to be at each apex.

Specifically, the fiber reinforced prepregs 27 to 30 of the prepreg group 10 are sequentially laminated on the outer periphery of the laminated body S of the fiber reinforced prepreg of the mandrel and the inner layer from the inner peripheral side. As shown in FIG. 3A, in the shaft cross section at the TIP end, four fiber reinforced prepregs 27 to 3 are used.
Winding start position 2 so that each of the four winding start positions 27a to 30a of 0 forms a square (regular quadrangle).
7a to 30a are laminated while being shifted in the circumferential direction. That is, on the circumference of the shaft cross section, the central angle is 0 °, 90 °
There are four winding start positions 27a to 30a at respective positions of 180 °, 270 ° and 180 °. FIG. 3 (B) shows a shaft cross section at a position 200 mm from the TIP end, and also at this position, a square is formed with the winding start positions 27a ′ to 30a ′ of the fiber reinforced prepregs 27 to 30 as vertices. In FIG. 3C, 300 from the TIP end
A shaft cross section at a position of mm is shown, and also at this position, a square is formed with the winding start positions 27a ″ to 30a ”of the fiber reinforced prepregs 27 to 30 as vertices.

Carbon fibers are used as the reinforcing fibers F21 to F30 of the fiber reinforced prepregs 21 to 30, and epoxy resin is used as the matrix resin.

The laminated construction of the fiber reinforced prepregs 21 to 30 will be described below. In the fiber reinforced prepregs 21 and 22, the fiber angles formed by the reinforced fibers F21 and F22 with respect to the shaft axis are −45 ° and + 45 ° (angle layer), respectively, and the tensile elastic modulus is 40,000 kgf / mm ² . The fiber reinforced prepreg 23 has a fiber angle of 90 ° (hoop layer) formed by the reinforcing fiber F23 with respect to the shaft axis and a tensile elastic modulus of 35000 kgf / mm ² . The fiber reinforced prepregs 24 to 26 have a fiber angle of 0 ° (straight layer) formed by the reinforcing fibers F24 to F26 with respect to the shaft axis and a tensile elastic modulus of 24000 kgf / mm ² . The fiber reinforced prepregs 27 to 30 are reinforced fibers F.
The fiber angle made by 27 to F30 with respect to the shaft axis is 0.
° (straight layer), tensile elastic modulus 24000kg
f / mm ² , prepreg basis weight 100 g / m ² , prepreg thickness 0.08 mm, prepreg length 300 m
m, and the width of the prepreg is 30 mm (manufactured by Mitsubishi Rayon Co., Ltd.). In the following, the angles shown in each figure are
The fiber angle of each fiber reinforced prepreg is used. The shape and width of the prepreg are as shown in the figure.

The shaft 1 is made by the sheet winding method, and is made of fiber reinforced prepregs 21 to 30.
On the core metal (not shown) in order (fiber reinforced prepreg 21
→ 22 → ... 30) After wrapping and stacking, wrapping with tape made of polyethylene terephthalate resin etc., heating and pressurizing in an oven to cure the resin, and integrally molding, and then pulling out the cored bar, shaft 1 is formed.

Thus, in the fiber reinforced prepregs 27 to 30 of the prepreg group 10, the winding start position 27
Since a to 30a are laminated so as to form a square apex, and this state is maintained at any position in the axial direction of the shaft, the physical properties of the shaft should be substantially uniform around the shaft axis (circumferential direction). You can Therefore,
The shaft strength and rigidity can be improved.

Further, in the above embodiment, the prepreg group is one set, but it may be two or more sets. Further, the number and shape of the fiber reinforced prepregs in the prepreg group can be set as appropriate, and the prepreg group can be provided over the entire length of the shaft.

Hereinafter, Examples 1 and 2 and Comparative Examples 1 to 3 of the golf club shaft of the present invention will be described in detail. Each,
Using a fiber reinforced prepreg having the following constitution, a golf club shaft was manufactured by a usual sheet winding manufacturing method. Table 1 below shows the lamination conditions of the tip reinforcing layer of the fiber-reinforced prepregs of Examples and Comparative Examples. The lamination conditions other than the tip reinforcing layer were all the same as those in the first embodiment. The shaft weight is 50 g and the shaft length is 11
The length is 70 mm, and is the same in each of the examples and comparative examples.

[0038]

[Table 1]

(Example 1) The same fiber-reinforced prepreg as that of the first embodiment was laminated, and the number of prepregs in the tip reinforcing layer was 4, and the width of the prepreg in each tip reinforcing layer was 3.
It was set to 0 mm. The winding start position was set at each of the central angles of 0 °, 90 °, 180 °, and 270 ° on the circumference of the shaft cross section.

(Example 2) The number of prepregs of the tip reinforcing layer was set to 3, and the width of the prepreg of each tip reinforcing layer was 40 m.
m. The winding start position was set at each of the central angles of 0 °, 120 °, and 240 ° on the circumference of the shaft cross section, and the major side was set to 4/3 ply. Others were the same as in Example 1. Specifically, FIG. 4 (A) (B)
As shown in (C) and (D), the fiber reinforced prepregs 37 to 39 were sequentially laminated on the outer periphery of the laminate S of the fiber reinforced prepreg of the mandrel and the inner layer from the inner periphery side. The winding start positions 37a to 39a at the TIP end were laminated so as to form a regular triangle. 200mm and 300mm from the TIP end
Also in the position, a regular triangle is formed with the winding start positions 37a 'to 39a' and 37a "to 39a" of the fiber reinforced prepregs 37 to 39 as vertices.

(Comparative Example 1) The number of prepregs of the tip reinforcing layer was set to 1, and the width of the prepreg of the tip reinforcing layer was 120 m.
m. The significant side was 4 ply. Others are Example 1
Same as. Specifically, FIG. 5 (A) (B) (C)
As shown in (D), the fiber reinforced prepreg 47 was laminated on the outer periphery of the laminated body S of the fiber reinforced prepreg of the mandrel and the inner layer from the inner periphery side in order from the winding start position 47a.
Winding start positions 47a ′ and 4 of the fiber reinforced prepreg 47 at positions 200 mm and 300 mm from the TIP end
7a "is shown as the same as the TIP end.

(Comparative Example 2) The number of prepregs of the tip reinforcing layer was set to 2, and the width of the prepreg of each tip reinforcing layer was 60 m.
m. The winding start position was set at each of the central angles of 0 ° and 90 ° on the circumference of the shaft cross section, and the large side was set at 2ply. Others were the same as in Example 1. Specifically, as shown in FIGS. 6 (A), (B), (C), and (D), the fiber-reinforced prepregs 57 and 58 are sequentially arranged on the outer periphery of the laminated body S of the fiber-reinforced prepreg of the mandrel and the inner layer from the inner periphery side. The layers were stacked from the winding start positions 57a and 58a. Winding start position 5 of the fiber reinforced prepregs 57 and 58 at positions of 200 mm and 300 mm from the TIP end
7a ', 58a' and 57a ", 58a" were as shown, as were the TIP ends.

(Comparative Example 3) The center angle of the winding start position was 0 °, 45 °, 90 ° on the circumference of the shaft cross section.
Each position was at 135 °. Others were the same as in Example 1. That is, only the winding start position is different from that of the first embodiment. As shown in FIGS. 7 (A), (B), and (C), the fiber-reinforced prepregs 67 to 70 are wound around the mandrel and the inner periphery of the laminate S of the fiber-reinforced prepregs in order from the inner circumference side to the winding start positions 67a to 70a. Laminated. TIP
Winding start positions 67a ′, 68 of the fiber reinforced prepregs 67 to 70 at positions of 200 mm and 300 mm from the ends.
a ', 69a', 70a 'and 67a ", 68a", 6
9a "and 70a" are as shown in the figure like the TIP end.

For the golf club shafts of Examples 1 and 2 and Comparative Examples 1 to 3, flex, three-point bending strength and crushing strength were measured by the methods described below. The measurement results are shown in the lower column of Table 1 above.

(Measuring Method of Forward Flex) The measuring method of the forward flex (W45 "position) described above is shown in FIG.
Shown in. A point 129 mm from the head side end 1a of the shaft 1 toward the grip side end 1b is a load point W, and a point 824 mm from the load point W toward the grip side end 1b is a first fulcrum T1. The second fulcrum T2 is located at 140 mm from T1 toward the grip side end 1b.
And The shaft 1 is fixed from below at the first fulcrum T1 and from above at the second fulcrum T2 so that the axial direction is horizontal, and the load point W when a 2.7 kg weight is hung at the load point W. Was measured. The cross section of the shaft is 0 °, 45 °, 90 °. It was measured from four directions of 135 °. (The 0 ° position means the winding start position of the innermost prepreg of the prepreg group having the same structure as described above.)

(Three-point bending strength test) What is three-point bending strength?
It is the SG type fracture strength defined by the Product Safety Association. As shown in FIG. 9, the shaft 50 was supported at three points, a load F was applied from above, and the load value (peak value) when the shaft 80 broke was measured. The measurement point was at a position 175 mm (point A) from the thin end of the shaft 80. The span of the supporting point 81 was 300 mm. The cross section of the shaft 80 was measured from two directions, 0 ° and 90 °. (The 0 ° position means the winding start position of the innermost prepreg of the prepreg group having the same structure as described above.)

(Crushing strength test) As shown in FIG.
A force F was applied to the shaft 80 from above in the direction of crushing the cross-sectional shape of the shaft, and the load value (peak value) when the shaft 80 was broken was evaluated as the crushing strength. The cross section of the shaft 80 was measured from two directions of 0 ° and 90 °. (The 0 ° position means the winding start position of the innermost prepreg of the prepreg group having the same structure as described above.)

As shown in Table 1, in Examples 1 and 2 in which the winding start position of each prepreg of the prepreg group having the same structure was defined, the difference (maximum −
(Minimum) is 0.2 and 0.1 respectively, the difference between the three-point bending strength measurement positions () is also three and one, and the difference between the crushing strength measurement positions is two and one, respectively. The value was very small as compared with Comparative Examples 1 to 3, and there was almost no variation in the shaft circumferential direction. As described above, since the respective physical property values of Examples 1 and 2 are values that have almost no difference depending on the measurement position, the golf club shaft of the present invention is
It was confirmed that the physical properties had no direction.

[0049]

As is apparent from the above description, according to the present invention, the winding start position of n fiber-reinforced prepregs having the same structure is defined, and the fiber-reinforced prepregs are evenly arranged around the shaft axis. This makes it possible to suppress variations in shaft strength, rigidity, etc., and make them substantially uniform. Therefore, it is possible to eliminate the directionality of the physical properties around the shaft axis and improve the shaft strength.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a fiber reinforced prepreg used in the golf club shaft of the first embodiment.

3A and 3B are schematic cross-sectional views of the shaft of the golf club shaft according to the first embodiment, in which FIG. 3A is a TIP end, FIG. 3B is a position 200 mm from the TIP end, and FIG. 3C is a position 300 mm from the TIP end. It is each sectional view.

FIG. 4 shows a fiber reinforced prepreg of a shaft of a golf club shaft of Example 2, (A) shows a fiber reinforced prepreg of a prepreg group, (B) is a TIP end, and (C) is a fiber reinforced prepreg.
Is a schematic cross-sectional view at a position 200 mm from the TIP end, and (D) is a schematic cross-sectional view at a position 300 mm from the TIP end.

FIG. 5 shows a fiber reinforced prepreg of a shaft of a golf club shaft of Comparative Example 1, (A) shows a fiber reinforced prepreg of a prepreg group, (B) is a TIP end, and (C).
Is a schematic cross-sectional view at a position 200 mm from the TIP end, and (D) is a schematic cross-sectional view at a position 300 mm from the TIP end.

FIG. 6 shows a fiber reinforced prepreg of a shaft of a golf club shaft of Comparative Example 2, (A) shows a fiber reinforced prepreg of a prepreg group, (B) shows a TIP end, and (C).
Is a schematic cross-sectional view at a position 200 mm from the TIP end, and (D) is a schematic cross-sectional view at a position 300 mm from the TIP end.

FIG. 7 is a schematic sectional view of a golf club shaft of Comparative Example 3, where (A) is a TIP end and (B) is a TI.
Position 200 mm from P end, (C) 30 from TIP end
It is each sectional view of the position of 0 mm.

FIG. 8 is a diagram showing a method of measuring a forward flex.

FIG. 9 is a diagram showing a method for measuring three-point bending strength.

FIG. 10 is a diagram showing a method for measuring crush strength.

[Explanation of symbols]

1 shaft 2 heads 3 grip 10 prepreg group 21-30 Fiber reinforced prepreg 27a to 30a Winding start position F21 to F30 Reinforcing fiber

Claims (5)

[Claims] 1. A golf club shaft made of a fiber reinforced resin comprising a laminate of fiber reinforced prepregs, wherein n fibers (n) having the same structure among the fiber reinforced prepregs are used.
≧ 3: n is an integer) and a prepreg group consisting of fiber reinforced prepregs is provided, and n of each fiber reinforced prepreg when n fiber reinforced prepregs of the above prepreg group are wound around the shaft axis.
The winding start position at each position is positive in the shaft cross section.
A golf club shaft, characterized in that each fiber-reinforced prepreg of the above prepreg group is laminated so as to have each vertex of a polygon. 2. The total number of turns on the BUTT side of each fiber reinforced prepreg of the prepreg group, and / or TIP.
The golf club shaft according to claim 1, wherein the total number of turns on the side is a non-integer. 3. The golf club shaft according to claim 1, wherein the fiber reinforced prepregs of the prepreg group have different numbers of turns on the BUTT side and the TIP side. 4. The golf club shaft according to claim 1, wherein each fiber-reinforced prepreg of the prepreg group is a straight layer in which reinforcing fibers are parallel to the shaft axis direction. 5. The fiber reinforced prepreg of the prepreg group is arranged within a range of 50% or less of a shaft total length from a TIP end of a shaft and / or a range of 50% or less of a shaft total length from a BUTT end of the shaft. The golf club shaft according to any one of claims 1 to 4.