JPH06254975A - Production of club shaft for golf - Google Patents

Abstract

PURPOSE:To achieve wt. reduction and the enhancement of moldability. CONSTITUTION:A shaft molding core metal material 10 is molded using a core part molding material 11 expanded in volume by heating at high temp. and an FRP molding material 12 is wound around the shaft molding core metal material 10 to mold a shaft molding material 20. This shaft molding material 20 is arranged in the cavity 31 of a mold 30 having a desired shaft shape and the mold 30 is clamped. High temp. heat treatment is applied to the mold 30 to expand the volume of the core part molding material 11 and inner pressure is applied to the FRP molding material 12 to cure and mold the material 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a golf club shaft having a hollow structure made of fiber reinforced plastics (hereinafter abbreviated as "FRP"), and particularly to a method for molding a shaft molding material at the time of molding. By making it possible to impart evenly, it is possible to reduce the weight and improve the moldability.

[0002]

2. Description of the Related Art Generally, golf club shafts are, for example, stainless steel shafts, GFRP shafts made of glass fiber reinforced plastic materials, CFRP shafts made of carbon fiber reinforced plastics, or stainless steel and carbon fiber reinforced shafts. A composite shaft using a combination of plastics and a CFRP hybrid shaft are known.

Conventionally, a golf club shaft of this type,
Especially when manufacturing FRP club shafts,
For example, for tube material made of resin film or rubber, F
A shaft molding material is formed by winding an RP molding material (for example, a prepreg), and the shaft molding material is placed in a molding die having a desired shaft shape and clamped. There is a configuration in which the FRP molding material forming the shaft molding material is subjected to pressurization / heat treatment while being expanded by applying internal pressure to the FRP molding material forming the shaft molding material.

[0004]

However, in the conventional method for manufacturing a golf club shaft described above, during molding, air is pumped into the tube material forming the shaft molding material to form the FRP molding material. When the tube material is expanded by applying internal pressure, the pressure tends to be locally concentrated in the tube material. Therefore, if a portion with low array density occurs due to the swimming (turbulence) of the reinforcing fibers in the FRP molding material, this density Part of the tube material swells out from the lower part of the index and the index cannot be applied evenly to the entire shaft molding material, resulting in a decrease in strength and defective molding due to uneven strength distribution. easy.

In order to prevent such a decrease in strength and the occurrence of molding defects, it is conceivable to increase the density of the reinforcing fibers of the FRP molding material forming the shaft molding material. There is a problem in that the weight of the entire club shaft inevitably increases.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for manufacturing a golf club shaft, which is capable of reducing weight and improving moldability.

[0007]

In order to solve the above-mentioned problems, the present invention comprises a step of molding a core metal material for shaft molding with a core molding material whose volume expands when heated at a high temperature, F around the shaft forming core material
The process of winding the RP molding material to form the shaft molding material, and curing the shaft molding material by placing it in a mold having the desired shaft shape, clamping it, and applying pressure and heat. And a step of molding, wherein the shaft-molding core metal material applies an internal pressure to the FRP-molding material by volume expansion of the core-molding material due to high temperature heating. It is a thing.

In this case, the core molding material is
For example, a foamable synthetic resin or a foamable inorganic compound is preferably used, and by utilizing the foaming pressure of the secondary foaming, an internal pressure is applied to the FRP molding material forming the shaft molding material. , This core molding material is
It is designed to be removed after the shaft is molded.

[0009]

That is, according to the present invention, by adopting the above-mentioned constitution, the core metal material for shaft molding is molded with the core molding material whose volume expands when heated at a high temperature. A FRP molding material is wound around a gold material to mold a shaft molding material, and the shaft molding material is placed in a molding die having a desired shaft shape, clamped, and subjected to high temperature heat treatment,
By expanding the volume of the core molding material, the FRP
Since it is designed to cure and mold while applying internal pressure to the molding material, it is possible to evenly apply internal pressure to the FRP molding material, which allows localized concentration of pressure as in the past. Is prevented.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the illustrated embodiments. FIG. 1 shows a golf wood club using a golf club shaft manufactured by the manufacturing process described later according to the present invention. 1, a shaft body 1 is shown.

As shown in FIG. 2, the shaft body 1 has a hollow structure made of FRP and has a taper tube whose diameter gradually increases from the mounting end 1a of the head 2 to the mounting end 1b of the grip 3. It comes from.

That is, the manufacturing process of the shaft body 1 will be described with reference to FIGS.
As shown in, a shaft forming core metal material 10 is formed.

The shaft forming core metal material 10 includes a core forming material 11 that expands and expands in volume by heating at a high temperature, such as an expandable synthetic resin or an expandable inorganic compound, in a mold (not shown). It is formed by arranging and primary foaming.

Next, as shown in FIG. 4, FR is formed around the shaft forming core metal material 10 thus formed.
The P-forming material 12 is wound to form the shaft-forming material 20.
Is placed in a cavity 31 in a mold 30 having a desired shaft shape, as shown in FIG.

In this state, the molding die 30 is clamped and heated at a high temperature, whereby the core metal material 1 for shaft molding is obtained.
By secondary foaming the core part forming material 11 forming 0, the volume of the core part forming material 11 is uniformly expanded,
The FRP molding material 12 is hardened and molded by uniformly applying an internal pressure to the FRP molding material 12 by this foaming pressure. The core part molding material 11 is decomposed and removed by further heating at high temperature after the shaft molding. It has become so.

[0016]

As is clear from the above description, according to the present invention, the core metal material for shaft molding is molded with the core molding material whose volume expands when heated at high temperature,
The FRP molding material is wound around the shaft molding core metal material to mold the shaft molding material, and the shaft molding material is placed in a molding die having a desired shaft shape and clamped at a high temperature. By heat-treating and expanding the volume of the core molding material, the FRP molding material is cured and molded while applying the internal pressure. Therefore, the FRP molding material is uniformly applied with the internal pressure. Therefore, it is possible to prevent local concentration of pressure as in the past, to make the strength distribution uniform, and to improve the formability.

Further, it is not necessary to increase the density of the reinforcing fibers of the FRP molding material forming the shaft molding material, so that the weight can be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a wood club using a golf club shaft according to the present invention.

FIG. 2 is an enlarged sectional view of the club shaft.

FIG. 3 is a sectional view showing a core metal material for forming a shaft, which is also used for manufacturing a club shaft.

FIG. 4 is a sectional view of a shaft molding material formed by winding a FRP molding material around a shaft molding core material.

FIG. 5 is a sectional view showing a state of disposing the shaft molding material in the molding die.

[Explanation of symbols]

10 ... Shaft molding core metal material, 11 ... Core metal molding material, 12 ... FRP molding material, 20 ... Shaft molding material, 30 ... Mold, 31 ... Cavity.

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Claims (2)

[Claims] 1. A step of molding a shaft forming core material with a core forming material whose volume expands when heated at a high temperature, and winding an FRP forming material around the shaft forming core material. And a step of molding the shaft molding material by placing the shaft molding material in a molding die having a desired shaft shape, clamping and pressurizing and heat-treating the material. A method for manufacturing a golf club shaft for golf according to claim 1, wherein the shaft forming core metal material is formed by applying an internal pressure to the FRP forming material by expanding the volume of the core forming material by heating at a high temperature. 2. A step of molding a core molding material for a shaft from a core molding material whose volume expands when heated at a high temperature, and winding a FRP molding material around the shaft molding core material. A step of molding the shaft molding material, and a step of placing the shaft molding material in a molding die having a desired shaft shape, clamping and pressurizing / heating to cure and mold. The shaft forming core material is applied to the FRP forming material by applying an internal pressure to the core forming material by expanding the volume of the core forming material by heating the core forming material at a high temperature, and is removed after the forming. Club shaft manufacturing method.