Somar Corporation

Tsuneo Akatsuka

Yoshihiro Motoki

Takashi Harada

Akira Suzawa

Kazutomo Moriguchi

Masatoyo Okitsu

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 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.

Golf club and golf club set

A golf club head 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.

Golf club head

A composite material is disclosed which includes a sheet of a prepreg including a multitude of substantially uniaxially oriented filaments having a diameter of 3-16 .mu.m and impregnated with a thermosetting resin, and a multiplicity of metal single fibers having a diameter of 50-300 .mu.m and bonded to at least one surface of the sheet with the thermosetting resin, the single fibers being spaced apart from each other with a predetermined space and arranged substantially in parallel with the filaments.

Metal single fiber-reinforced prepreg

A light weight, high strength carbon fiber golf culb shaft includes inner, intermediate and outer tubular layers formed of carbon fiber-reinforced plastic. The intermediate layer is formed of high modulus, high strength carbon fibers having a modulus of 35000 kg/mm.sup.2 or more while the outer layer is formed of high strength carbon fibers having a modulus of 23000-30000 kg/mm.sup.2. Th carbon fibers of the intermediate and outer layers are oriented at an angle in the range of 0 to 15 degrees with respect to the longitudinal axis of the shaft, while the carbon fibers of the inner layer are oriented at an angle of 30 to 80 degrees. The weight ratio of the intermediate layer to the outer layer ranges from 15:85 to 50:50, and the weight of the inner layer is 30-60 % by weight based on the total weight of the three layers. The shaft has a rigidity of 220-240 cycles per minute in terms of frequency and a weight of 63 g or less in the axial length of 1143 mm from the tip end.

Growing community of inventors

Saitama, Japan

Tsuneo Akatsuka