Yamaha Corporation

Nippon Gakki Seizo Kabushiki Kaisha

Tetsuyuki Awano

Kunimasa Muroi

Masanori Takatsuka

Yoshinari Inagaki

A tennis racket frame having the head and shaft, preferably made of a hollow FRP material, have uniform thickness along the longitudinal direction of the racket frame in a range from 23 to 28 mm with a natural frequency in a range from 160 to 260 Hz. Raised product of the Young's modulus (E) and moment of inertia of area (I) of the racket frame much improves its repulsion characteristics for long distance shot accurately in an intended direction. The specified natural frequency makes the vibrately performance of the racket frame very close to that of balls just after striking so that the vibration energy of the racket frame should be efficiently utilized for acceleration of balls. Further, the increased thickness of the head end assures raised accuracy in striking even when a ball is struck by a section of the face near the head end.

Hollow tennis racket frame with matched frequency of vibration

In construction of a racket frame provided with at least one string protector coupled to the outer peripheral surface of its head, at least one weight adjusting element is removably attached to the outer peripheral surface of the string protector for easy weight adjustment by users even after formation of a face in tension.

Racket frame

A racket includes a head portion having a peripheral notch located therein. A string protector comprised of a connecting section having first and second resilient tongues is situated within the peripheral notch. Each of the tongues has an elongated projection extending therefrom such that the projections oppose each other. The connecting section also has tubular string guides extending therefrom for receiving a racket string. The force of the racket strings tends to push the string protector into the peripheral notch of the head portion, thereby forcing the resilient tongues toward each other so as to close over the strings.

Growing community of inventors

Hamamatsu, Japan

Tetsuyuki Awano