Mitsubishi Rayon Company, Limited

Ikuo Takiguchi

Tsutomu Ibuki

Tetsuya Atsumi

Katsumi Anai

Shiro Asada

Akira Agata

Toshihiro Hattori

Fujio Itani

A golf club shaft is 35-50 percent lighter than a conventional shaft while maintaining the outer diameter and structural characteristics of conventional shafts. The shaft has at least four layers of fiber reinforced material. The fiber reinforced layers are from innermost to outermost: a first angled layer; a first straight layer; a second angled layer; and a second straight layer. The angled layers are formed by bonding together two materials, each with fibers aligned in different directions. The second angled layer maintains the proper strength and rigidity of the shaft while keeping the shaft as light weight as possible. Aligning the second layer's fibers at an angle of 35-75 degrees with respect to the longitudinal direction of the shaft ensures proper weight and strength characteristics of the shaft. The resulting shaft is light-weight and exhibits the flexural rigidity, flexural strength, torsional rigidity, torsional strength, and crushing strength of conventional shafts.

Shaft for light-weight golf clubs

A golf club shaft having an optimal set of materials and sloped sections provides appropriately high rigidity, ease of use, and is inexpensive and easy to manufacture. A sloped section expands toward a grip end of the shaft. The sloped section has a slope gradient from 15/1000 to 35/1000 and a length from 200 to 350 mm. The outer diameter of the grip end is from 18 to 25 mm. On the side of the sloped section toward an end, there is formed a semi-sloped section with a slope gradient from 4/1000 to 13/1000. A kick point is formed at a position from 40% to 46% from the small-diameter end relative to the total shaft length. The number of required parts is small while production is simple. The shaft is light, has appropriate hardness, and high rigidity at the grip. Furthermore, the strength of the shaft is balanced and provides a good feel when hitting a ball. Production of the golf club shaft can be accomplished with standard materials such as fiber-reinforced resins. By wrapping a fiber-reinforced resin around a mandrel and rolling the material on a base which is heated to an optimal temperature, the strength and rigidity of the shaft can be optimized. Multiple layers can be overlaid to provide any desired strength and rigidity required. The rolled shaft is then heated to set the resin and produce a golf club shaft of optimal performance and reduced cost.

Golf club shaft and method for manufacturing same

Moldings and method for forming the same

A novel unidirectionally paralleled fiber reinforced thermosetting resin prepreg excellent in moldability which has plural grooves arranged continuously in longitudinal direction on at least one side surface thereof.

Prepreg and process for producing the same

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Toyohashi, Japan

Ikuo Takiguchi