PURPOSE: To perform an evaluation test of a golf ball by rotating the golf ball, arranged in liquid, in a fixed rotary speed while detecting a resistance of rotation of the respective ball by a torque detector and an arithmetic processor and comparing a difference between the resistance values of rotation in a seam direction and a ball direction with a reference value.
CONSTITUTION: A golf ball 1a, arranged in a vessel 10 filled with liquid W, is rotated by a variable control motor 5 in a fixed speed (4,000rpm), and detecting a signal of rotation of the golf ball 1a by a torque detector 2, the signal of rotation is output to an arithmetic processor 6, while a control signal is output to the torque detector 2 from the arithmetic processor 6. The detected resistance value of rotation of the golf balls 1a, 1b is printed out by a printer 7. When a difference between the resistance values of rotation of the golf balls 1a, 1b is smaller than the reference value, the golf ball 1, being evaluated with no difference on a flying quality by the ball hitting position, is decided to be in good symmetrization. When the difference between the resistance values of rotation is larger than the preset value, the golf ball is evaluated to be in bad symmetrization.
NINOMIYA TOSHIRO
NIWANO YOSHIAKI
