JPS5916785B2 - golf club shaft - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shaft for a golf club manufactured by a filament winding method.The present invention relates to a shaft for a golf club manufactured by a filament winding method.The present invention relates to a shaft for a golf club manufactured by a filament winding method. To provide a safe carbon shaft in which organic fibers do not break even if some of the carbon fibers break due to severe bending.

Conventional carbon golf shafts are manufactured by winding carbon fibers impregnated with epoxy resin around a steel mandrel using a filament winding method and curing the shaft by heating, or by winding a carbon fiber prepreg sheet and curing the shaft. Carbon fibers have a small breaking strain, so if a large impact force is applied to them, the fibers will break instantaneously and part of the club may break and fly off, which is dangerous. The present invention has been made to solve the above-mentioned drawbacks.

That is, the present invention provides a filament winding characterized in that the innermost layer is made of organic fibers having a larger breaking strain than carbon fibers with a winding angle of 200 or less, and the outermost layer is made of carbon fibers with a winding angle of 200 or less. Regarding fiber-reinforced plastic golf club shafts manufactured by the 5 method, we have created a hybrid shaft of organic fibers and carbon fibers that has a large breaking strain, and even if some of the carbon fibers are cut off by an impactful force, the organic fibers will remain intact. The present invention provides a shaft with a winding configuration that does not require cutting.

Golf shafts produce 00 shear strain due to torsion and compression and tensile strain due to bending during swing, but breakage occurs when a bending moment momentarily larger than the effect of torsion occurs, so it must be strong against breakage due to bending moments. Must be. The relationship between the breaking strength due to bending of the shaft and the winding angle of the fiber with respect to the axial direction j5 is measured as shown in FIG. 1. The measurements were carried out using a carbon fiber cross-laminated material wound by the filament winding method, with an inner diameter of 10 and an outer diameter of 137 mm, a span of 300 mm, the maximum load was determined by the 3-point bending method, and the bending strength was determined from that value. The relationship between the winding angle and bending strength of pipes manufactured by the filament winding method is as shown in Figure 1, and the same tendency is shown in the case of organic fibers. This shows that when the winding angle is set to 200 or less, the bending strength increases rapidly and becomes stronger. Also, regarding the breaking strain, carbon fiber is about 1% and organic fiber is more than 2%.
If both have the same strain, even if the carbon fiber is cut, the organic fiber will not be cut.

Therefore, by creating a hybrid structure of organic fibers and carbon fibers with a winding angle of 20 layers or less, which has a larger breaking strain than carbon fibers, a bending moment due to an impact force will be applied to the shaft, causing some of the carbon fibers to break. In addition, since the strain caused by the bending moment becomes smaller towards the inside of the shaft, wrapping organic fibers around the innermost layer makes it more difficult for the fibers to break.

Especially the shaft wall thickness on the small diameter side is about 2mW! ．． The shaft wall thickness on the large diameter side is approximately 1 mm, and since the thin diameter side is the part that is prone to breakage due to the bending moment that occurs when force is applied to the head of the club, the innermost layer is made of organic fiber to make it a golf club that is resistant to breakage. As an organic fiber with which a shaft can be obtained and which has a larger breaking strain than carbon fiber, for example, a high modulus organic fiber Kevlar 49 (trade name) manufactured by DuPont is used. As shown in Table 1, the high modulus organic fiber Kevlar 49 has a specific elastic modulus that does not decrease much compared to carbon fiber, so compared to 100% CABO 7 fiber, the mechanical properties of the shaft hardly change and the specific gravity is similar to that of carbon fiber. It is a desirable fiber because it is smaller. Next, the golf club shaft of the present invention will be described with reference to Examples.

FIG. 2 shows a cross-sectional view of a golf shaft manufactured by the filament winding method of the present invention.

The golf shaft shown in Figure 2 has ultra-strength, ultra-high elasticity organic fiber [KEVLAR-49 manufactured by Dupont Company] in the innermost layer by filament winding to account for 10% of the total fiber weight. The outermost layer is wrapped with carbon fiber of 30 to 500 mm, such as TORAYCA-T2OOA made by Toray, and the outermost layer is again wrapped with 5A to 9A carbon fiber.

A bisphenol epoxy resin was used as the matrix resin. Dimensions are the smallest diameter of the tip 7.8m71! The grip side has a maximum diameter of 16 mm and a length of 451 nm. An impact test was conducted using an Izot impact tester by checking at a point 100 mI from the tip of the shaft obtained by the present invention and a shaft made only of carbon fiber. The value is 63
Although the shaft made only of carbon fibers was completely broken, the outer carbon fibers were broken, but the innermost Kevlar fiber was broken. It remained almost unbroken and did not break instantaneously due to impact fracture. This means that the manufacturing process for hybrid shafts made of organic fibers and carbon fibers is less complicated than for shafts made only of carbon fibers, and if a club using such a shaft breaks due to impact, a club made of shafts made only of carbon fibers will be replaced. It is safe because there is no danger of part of the club flying off when it breaks.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between the fiber winding angle and the bending strength of a carbon fiber-epoxy resin strength material manufactured by the filament winding method. FIG. 2 is a cross-sectional view of a carbon golf shaft containing organic fibers. Explanation of symbols, 1...De-9 winding carbon fiber layer, 2...30-50 winding carbon fiber layer, 3...5-9 winding organic fiber layer.

Claims (1)

[Claims] 1 Manufactured by a filament winding method characterized in that the innermost layer is made of organic fibers with a larger breaking strain than carbon fibers with a winding angle of 20 degrees or less, and the outermost layer is made of carbon fibers with a winding angle of 20 degrees or less. A golf club shaft made of fiber-reinforced plastic.