Somar Corporation

Akira Suzawa

Yoshihiro Motoki

Takashi Harada

Tsuneo Akatsuka

A golf club shaft is formed of a fiber-reinforced plastic is disclosed which has a constant inside diameter of at least 7 mm between the tip end and a point G1 and a varying inside diameter increasing from the point G1 to a point G2, wherein G1 and G2 are located at positions spaced apart from the tip end distances equal to 20-50% and 70-100% of the length of the shaft, respectively. The shaft has a constant outer diameter of at least 8 mm between the tip end and a point H1 which is spaced apart from the tip end a distance equal to 20-170 mm, a varying outer diameter decreasing from H1 a point F1 which is spaced apart from the tip end a distance equal to 10-45% of the shaft, a constant diameter from F1 to a point F2 which is spaced apart from F1 a distance equal to 0-300 mm and a varying outer diameter increasing from F2 to a point H2 which is spaced apart from the grip end a distance equal to 0-300 mm.

Golf club shaft

A hollow, fiber-reinforced plastic golf club shaft is disclosed which is tapered from the grip to the hosel and which is provided with an enlarged portion in an intermediate portion so that the flexural rigidity of the shaft is abruptly changed at the enlarged portion.

A light weight golf club shaft is disclosed which has an average weight of not greater than 1.4 g per inch and which is composed of an inner tubular layer of a carbon fiber reinforced plastic having a fiber orientation angle of 40 to 50 degrees with respect to the longitudinal axis of the shaft and an outer tubular layer of a carbon fiber reinforced plastic provided around the inner layer and having a fiber orientation angle of 5 to 30 degrees. The inner layer is obtained from a prepreg sheet by a sheet winding method, while the outer layer is obtained from a roving carbon fibers by a filament winding method. The inner layer has been hardened before the winding of the roving. A reinforcing layer obtained from a prepreg and having a fiber orientation angle of 0 to 5 degrees is provided inside of the inner layer at the tip portion of the shaft.

Golf club shaft and process of preparing same

A golf club having a club number in the range of Nos. 1 through 5 and including a club shaft, and a head connected to one end thereof and having the center of mass located below the half face height. The club head includes a top surface, a sole disposed opposite to the top surface, a toe portion, a heel portion opposite to the toe portion, a front, impact face located between the toe and heel portions, a rear portion located opposite to the face and between the toe and heel portions. The toe and rear portions together form a smooth, continuous, enlarged side surface so that an upper section of the club head above the horizontal center plane, which passes the half height of the face portion, has a volume smaller than that of a lower section of the club head below the horizontal center plane. The club shaft has not greater than 2 g/in. of a ratio of the weight thereof to the length thereof and a kick point located at a position spaced apart from the one end a distance equal to 44% or more of the total length thereof.

Growing community of inventors

Koshigaya, Japan

Akira Suzawa