Sumitomo Rubber Industries Limited

Kenichi Miyamoto

Haruyoshi Minamiguchi

Golf club set

A tennis racket frame, made of fiber-reinforced resin, in which the volume percentage of aromatic polyamide fiber and/or all-aromatic polyester fiber of all fiber-reinforcing materials of a throat section, a flake section, and a handle section is 40 or more and smaller than 80, respectively. The sectional configuration of the flake section and that of the handle section are set so that the geometrical moment of inertia of the handle section is greater than that of the flake section.

Tennis racket frame

A composite prepreg for producing a tennis racket, which is light and tough and superior in flexibility and vibration absorption abilities, comprises thermosetting resin and reinforcing fibers, wherein the reinforcing fibers are a combination of (a) aromatic polyamide or polyester fibers and (b) carbon fibers, the fibers (a) being formed into a first type of strand and the fibers (b) being formed into a second type of strand, the first and second types of strand being arranged with certain regularity. The present invention is also directed to a tennis racket comprising a circular frame constituting a ball hitting area and a shaft connecting with the circular frame, the frame and shaft having a plurality of layers structured so that at least one layer is formed from the above described composite prepreg.

Composite prepeg and tennis rackets using the same

Disclosed is a composite prepreg for producing a tennis racket which is light and tough and superior in flexibility and vibration absorption abilities. The composite prepreg comprises thermosetting resin and reinforcing fibers, wherein the reinforcing fibers are a combination of (a) aromatic polyamide or polyester fibers and (b) carbon fibers and the fibers (a) and (b) are arranged with certain regularity. The present invention also provides a tennis racket comprising a circular frame constituting a ball hitting area and a shaft connecting with the circular frame, the frame and shaft having a plurality of layers structured so that at least one layer is formed from the above mentioned composite prepreg.

Composite prepreg and tennis rackets using the same

A tennis racket which includes a main frame portion having an oval shape which is defined by a top portion, side portions; and a yoke portion, a grip portion contiguous with the yoke portion, and a netting stretched in the oval main frame by main strings and cross strings to form a ball striking face with a sweet area provided therein, wherein the ratio of the rigidity in the ball striking direction, which is the thickness direction of the frame to the rigidity in the main string direction, and the ratio of the rigidity in the ball striking direction, which is the thickness direction of the frame, to the rigidity in the cross string direction, are each set to be larger than 1.00 and smaller than 2.00, and the rigidity ratio of the frame within the ball striking face including the ratio of the rigidity in the main string direction to the rigidity in the cross string direction of said strings is set to be smaller than 1.00.

Growing community of inventors

Akashi, Japan

Kenichi Miyamoto