US 5,685,783 AGranted

Golf club shaft

AssigneeSomar Corporation

InventorsTsuneo Akatsuka, Yoshihiro Motoki, Takashi Harada, Akira Suzawa

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Abstract

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.

A hollow golf club shaft formed of a fiber-reinforced plastic and having a tip end and a grip end spaced apart from said tip end a distance equal to 810-1,300 mm,

said golf club shaft comprising in adjacent order from said tip end to said grip end a tip section, a first intermediate section, a minimum torsional rigidity section, a second intermediate section, and a grip section;
said golf club shaft having a kick point located at a position spaced apart from said tip end a distance equal to 40-47% of the length from said tip end to said grip end;
said golf club shaft having a constant inside diameter of at least 7 mm between said tip end and a first point G1 and a varying inside diameter increasing from said first point G1 to a second point G2;
said first point G1 being located at a position spaced apart from said tip end a distance equal to 20-50% of the length from said tip end to said grip end;
said second point G2 being located at a position spaced apart from said grip end a distance greater than zero percent and less than or equal to 30% of the length from said tip end to said grip end;
said tip section having a constant outer diameter of at least 8 mm;
said first intermediate section having varying outer diameter decreasing from its junction H1 with said tip section to its junction F1 with said minimum torsional rigidity section;
said junction H1 being located at a position between said tip end and said first point G1 and spaced apart from said tip end a distance equal to 20-170mm;
said junction F1 being spaced apart from said tip end a distance equal to 10-45% of the length from said tip end to said grip end;
said minimum torsional rigidity section having a length greater than zero mm and less than or equal to 300 mm;
said second intermediate section having varying outer diameter increasing from its junction F2 with said minimum torsional rigidity section to its junction H2 with said grip section;
and
said junction H2 being spaced apart from said grip end a distance greater than zero mm and less than or equal to 300 mm.

10 more elements

Abstract

Claims8