JP2001137401A - Golf shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a golf shaft which obviates the occurrence of directivity in the bending of a shaft in a portion subjected to reinforcement, is improved in the direction of a hit ball and improves feeling. SOLUTION: Regulating prepreg sheets 5 arranged at suitable lengths at proper points of the overall length of the shaft are so formed that the upper side 5a and lower side 5b which are approximately parallel to the axial direction of the mandrel 4 and are inclined to meet the taper angle of the mandrel and two lateral edges 5c and 5d between these two sides is formed in the direction perpendicular to the axial direction of the mandrel 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a golf shaft made of FRP, and
The present invention relates to a golf shaft that improves the directionality of a hit ball when hit.

[0002]

2. Description of the Related Art For example, in a golf shaft made of FRP, a sheet winding method (hereinafter referred to as SW method) and a filament winding method (hereinafter referred to as FW method).
Is known. The SW method has a relatively simple manufacturing method and simple manufacturing equipment as compared with the FW method, can be manufactured at low cost, and has a low resin content prepreg material and further advanced reinforcement. Since the appearance of fibers and the like is advantageous in terms of weight reduction, it is a general golf shaft manufacturing method.

[0003] As shown in FIG. 3, a golf shaft manufactured by the SW method is configured such that reinforcing fibers are aligned in one direction, and a prepreg sheet impregnated with a synthetic resin is cut into a predetermined shape and size. The prepreg sheet is wound around a tapered mandrel 4 serving as a material, and the matrix resin of the prepreg sheet is cured.

That is, the prepreg sheet includes a prepreg sheet that is disposed over the entire length of the golf shaft and forms a shaft main body, and a prepreg sheet that is disposed at an appropriate position in the longitudinal direction of the golf shaft and a predetermined length as necessary. Reinforced prepreg sheet 15. The prepreg sheet extending over the entire length includes bias prepregs 1 and 2 arranged such that reinforcing fibers constituting the prepreg sheet are inclined at angles of ± 35 ° to ± 45 ° in directions opposite to each other with respect to the axial direction of the golf shaft. And a straight prepreg 3 in which reinforcing fibers are arranged in parallel to the axial direction of the golf shaft, and are laminated. Usually, high elasticity reinforcing fibers are used for the bias prepregs 1 and 2, and high strength reinforcing fibers are used for the straight prepreg 3.

The reinforcing prepreg sheet 15
The length of the prepreg sheet, which is shorter than the prepreg sheet that forms the entire length of the golf shaft, is mainly used in the tip region and the grip portion side region of the golf shaft for reinforcement and kick point adjustment to secure breaking strength. Used and wound. This reinforcing prepreg sheet 15 is used for adjusting the outer diameter together with the reinforcing, and is generally used for reinforcing the bending rigidity in the longitudinal direction of the golf shaft. A prepreg sheet having a breaking elongation ratio and a bending elastic modulus similar to those of the straight prepreg 3 is used as a straight prepreg in which reinforcing fibers are arranged in the axial direction.

The shape of the prepreg sheet for forming the main body is such that two sides c and d between two sides of an upper side a and a lower side b substantially parallel to the axial direction of the mandrel 4 extend in the axial direction of the mandrel 4. On the other hand, the reinforcing prepreg sheet 15 has a quadrilateral that is perpendicular to the upper side 15a and a lower side 15b. It was formed in an unequal leg trapezoidal shape.

Therefore, the reinforcing prepreg sheet 1
For example, as shown in FIG. 4, when the reinforcing prepreg sheet 15 is wound around the mandrel 4, as shown in FIG. Is wound around the mandrel 4 so that the oblique side 15d is on the large-diameter side, so that the length of the reinforcing prepreg sheet 15 extends along the circumferential direction of the mandrel 4 on the oblique side 15d. Thus, the stress at the time of impact is prevented from being concentrated on the oblique side 15d, thereby preventing the joint portion from decreasing in strength.

[0008]

According to the above-described conventional winding configuration of the reinforcing prepreg sheet 15, the step due to the winding of the reinforcing prepreg sheet 15 can be dispersed, and the concentration of stress can be avoided to some extent. . However, the length of the reinforcing prepreg sheet 15 wound around the mandrel 4 changes along the circumferential direction of the mandrel 4, and the fiber length from the winding start portion becomes different toward the end of winding. .

This difference is greatest at the winding end 15e with respect to the winding start 15f, but the rigidity of the golf shaft varies slightly depending on the circumferential position due to the structure in which the lengths of the fibers are different. This results in a different feeling when hit. The present invention solves the above problems, eliminates the occurrence of directionality in the bending of the golf shaft in the reinforced portion, and aims to improve the directionality of the hit ball and improve the feeling. The purpose is to provide.

[0010]

In order to achieve the above object, the invention according to claim 1 comprises a main body prepreg sheet forming the entire length of the golf shaft, and an adjustment prepreg sheet arranged at an appropriate position in the appropriate position of the entire length. In the golf shaft formed by winding and laminating the main body prepreg sheet and the adjustment prepreg sheet, the adjustment prepreg sheet is formed of a reinforcing fiber having a tensile modulus of 100 GPa or less, and has a shape of a mandrel. A golf shaft, wherein an upper side, a lower side, and two sides between the two sides in the axial direction are formed by sides that are perpendicular to the axial direction of the mandrel.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on preferred embodiments shown in the drawings. FIG. 1 is a diagram illustrating a laminated configuration of the golf shaft of the present invention. This golf shaft is formed, for example, by winding and laminating the plurality of prepreg sheets shown in FIG. 1. As the prepreg sheet, a main body prepreg sheet forming the entire length of the shaft is used. And bias straight prepregs 1 and 2 in which the disposing direction is inclined ± 30 ° to 60 °, and straight prepregs 3 in which the disposing direction of the reinforcing fibers is substantially parallel to the shaft axis direction. The whole is generally trapezoidal. In addition,
In this embodiment, the inclination angle θ of the reinforcing fiber of the bias prepreg 1 is set to + 45 °, and the inclination angle θ of the reinforcing fiber of the bias prepreg 2 is set to −45 °. is not.

Normally, the adjustment prepreg sheets 5 and 6 are arranged at appropriate positions along the entire length, such as the tip end region and the grip portion side region of the golf shaft. In the present embodiment, the adjustment prepreg sheets 5 and 6 are arranged in the front end region, and the shape of the adjustment prepreg sheets 5 and 6 is substantially parallel to the axial direction of the mandrel 4 as shown in FIG. The upper side 5a, 6a and the lower side 5b, 6b inclined in accordance with the degree of taper, and the two side sides 5c, 6c, 5d, 6d between the two sides are perpendicular to the axial direction of the mandrel 4. The formed one is used.

The main body prepreg sheet is formed by arranging reinforcing fibers such as carbon fibers and glass fibers in respective directions, and impregnating with a thermosetting resin such as an epoxy resin to form a prepreg. Further, as a characteristic of the above-mentioned reinforcing fiber, the tensile elastic modulus is 200 to 800 G.
The one of Pa is generally used.

The adjusting prepreg sheet 5 used in the present invention is a prepreg sheet made of a reinforcing fiber having a lower elasticity than the main body prepreg sheet for the purpose of increasing the strength by relatively suppressing increase in bending rigidity of the shaft. used.

In order to form the golf shaft of this embodiment, the bias prepreg 1 is first placed on the tapered mandrel 4 shown in FIG. 1 and having a gradually increasing diameter from the distal end 7 to the proximal end 8. The bias prepreg 2 is wound thereon, and the straight prepreg 3 is further wound thereon. And, for example, 200 mm from the tip 7 side
Adjustment prepreg sheets 5 and 6 made of reinforcing fibers having a tensile elasticity of about 10 to 100 GPa are wound in two layers, and then taping and heating and firing are performed to remove the mandrel 4. A golf shaft is formed by performing tape peeling or the like.

The adjustment prepreg sheets 5 and 6 are provided with respective side edges 5 c and 6 of the adjustment prepreg sheets 5 and 6.
Since c, 5d, and 6d have shapes perpendicular to the axial direction of the mandrel 4, the length of the reinforcing fiber does not change depending on the position in the circumferential direction. Therefore, the bending rigidity of the shaft does not change depending on the circumferential position, and the directivity of the golf shaft is improved. The reinforcing fibers constituting the adjustment prepreg sheets 5 and 6 have a tensile elastic modulus of 1
Those having 0 GPa or more and 100 GPa or less are preferably used, and those having 40 to 60 GPa are more preferably used. It is not preferable that the tensile elasticity is 100 GPa or more, since stress is concentrated on the disposition end of the prepreg sheet, which easily leads to breakage. Also, 10GP
A value of less than a is not preferable because the purpose of adjusting the bending rigidity and strength cannot be achieved. In general, it is desirable to arrange an adjustment prepreg sheet other than the prepreg sheet for forming a main body according to the present invention, at the outermost layer or near the outermost layer, because it is efficient as reinforcement and is desirable.

The adjustment prepreg sheets 5, 6
Since the side edges 5c, 6c, 5d, and 6d are perpendicular to the axial direction of the mandrel 4, it is preferable to wind each layer. When winding multiple layers, the length of the upper and lower sides is changed for each layer, and the upper and lower sides are changed from the inner layer to the outer layer.
It winds so that a lower side may become a short layer sequentially. When a plurality of adjustment sheets of the same length are stacked and wound, stress is concentrated on the winding end, which may lead to breakage of the golf shaft.

[0018]

The present invention will be described more specifically with reference to the following examples. As a prepreg sheet for forming a main body, 20
0-400 GPa carbon fiber prepreg (resin content 3
5% by weight) and cut into the fiber direction and size shown in FIG. The bias prepregs 1 and 2 were laminated and bonded so that the fiber directions were perpendicular to each other. Total length 1600m
m, a prepreg was wound around a metal mandrel 4 having a small diameter of 3.3 mmφ and a large diameter of 18.8 mmφ to perform molding. First, the bonded prepregs of the bias prepregs 1 and 2 are wound, and the straight prepreg 3 is placed thereon in the same manner.
Was wound in two plies. And 200 from the tip 7 side
prepreg sheets 5 and 6 (carbon fiber prepreg having a tensile modulus of elasticity of 50 GPa, resin content 3
3% by weight and a thickness of 100 g / m ² ). A polypropylene tape was wrapped around the outside and placed in a curing oven and cured by heating. The polypropylene tape was removed, the mandrel 4 was removed, and a golf shaft having a total length of 1140 mm was obtained.

The shaft of the comparative example uses a carbon fiber prepreg having a tensile modulus of elasticity of 240 GPa as an adjustment prepreg sheet, and has an upper side of 200 mm, a lower side of 300 mm, and a right side of 2 mm.
A golf shaft was formed in the same configuration as that of the example except that an unequal leg trapezoid having a hypotenuse of 5 mm was used.

From the tip of these golf shafts, 300
As a guide for verifying the directivity in mm, the deflection amounts at three locations (60 ° intervals) in the circumferential direction of the shaft were measured and are shown in Table 1. The measurement of the amount of deflection is based on a cantilever bending test with the shaft tip supported.

[0021]

[Table 1]

[0022]

According to the present invention, as described above, the adjustment prepreg sheet used at an appropriate position along the entire length of the shaft is formed of a reinforcing fiber having a tensile modulus of elasticity of 100 GPa or less, and its shape is adjusted to the side of the adjustment prepreg sheet. Since the side is formed in a shape perpendicular to the axial direction of the mandrel, even if the adjustment prepreg sheet is wound around the outside of the main body prepreg sheet, breakage in the vicinity of the side side due to bending of the golf shaft is prevented. Without imitating, it is possible to make the bending rigidity in the circumferential direction of the golf shaft uniform and improve the feel at the time of hitting.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an embodiment of a laminated structure of a golf shaft according to the present invention.

FIG. 2 is a diagram illustrating an adjustment prepreg sheet.

FIG. 3 is a diagram illustrating a laminated configuration of a conventional golf shaft.

FIG. 4 is a diagram illustrating a state in which a reinforcing prepreg sheet of a conventional golf shaft is wound.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bias prepreg 2 Bias prepreg 3 Straight prepreg 4 Mandrel 5 Adjustment prepreg sheet 5a Upper side 5b Lower side 5c Side 5d Side 6 Adjustment prepreg sheet 6a Upper side 6b Lower side 6c Side 6d Side 7 Tip prepreg 8 Base prep 15a Upper side 15b Lower side 15c Right angle side 15d Oblique side 15e End of winding 15f Beginning of winding a Upper side b Lower side c Side d Side

Claims (1)

[Claims] 1. A golf club comprising: a main body prepreg sheet forming the entire length of a golf shaft; and an adjustment prepreg sheet arranged at an appropriate position at an appropriate position along the entire length. The main body prepreg sheet and the adjustment prepreg sheet are wound and laminated. In the golf shaft to be formed, the adjustment prepreg sheet is made of a reinforcing fiber having a tensile elasticity of 100 GPa or less, and has a shape in which an upper side, a lower side, and two sides between the two sides of the mandrel in the axial direction are mandrel. A golf shaft characterized by being formed by sides that are perpendicular to the axial direction of the golf shaft.