PURPOSE: To attenuate quickly effectively impact vibrations in driving a ball for reducing the fatigue of arms and elbows by mounting a combined material composed of a vibration damping material and specified buffer material near the center of gravity of a racket.
CONSTITUTION: A vibration damping material 3 serves mainly to attenuate impact vibrations. A wooden material, elastic rubber, synthetic resin, cork, felt-like material, metal such as iron, copper, etc., high specific gravity ceramic and a mixture thereof are used for the vibration damping member 3. A buffer material 4 functions to improve and aid the attenuation of the impact vibrations due to the vibration damping material 3. The buffer material 4 having 5.0kg/cm2 or less of compression hardness is 25% compression specified according to JIS K6767 is excellent in the attenuating action. A combined material 5 may be made of several layers of combined vibration damping material 3 and buffer material 4, and the combined structure may be either of longitudinal, lateral and bias or mixture thereof, so that the impact vibration transmitted to trainee's grip can be attenuated satisfactorily in driving a ball.
EDAKAWA HIROSHI
KOMATSU YASUO
