| 摘要 |
PURPOSE: To lower the attraction generated in a racket at the time of swinging so as to obtain a higher swinging speed and to create a faster and stronger shot ball by forming dimples on a frame surface. CONSTITUTION: An effect is obtainable even if all the dimples 3 in the frame 1 of the one racket are respectively unified in the diameter, depth and intervals 4, 5 of the dimples 3 formed on the frame surface. The larger effect is, however, obtd. in many cases when the dimples are changed according to the parts in the frame 1 to be formed. More particularly, at least the intervals 4, 5 are preferably changed by the parts. For example, the dimples are formed at a high density (i.e., at the short intervals) in the corner parts from the face on the side parallel with a ball fitting face to the flanks in the part of the frame 1. On the other hand, the dimples are preferably formed at a low density (i.e., at the long intervals) on the flat surface. |
