| 摘要 |
PURPOSE:To effectively lessen the air resistance at the time of swinging a racket by providing this racket with a head frame delineating a gut extension part and a shaft including a grip part and forming plural pieces of recesses on the surfaces. CONSTITUTION:This tennis racket has the head frame delineating the gut extension part 1 and the shaft 3 including the grip part. In such a case, the surfaces, particularly the inner peripheral side surface 2a and the outer peripheral side surface 2b of the head frame 2 are provided with the recesses 4a, 4b having edge part contour shapes over nearly the entire periphery of the head frame 2. These recesses 4a, 4b are formed to one kind or plural kinds of nearly circular shapes of a diameter 0.5 to 10.0mm and depth 0.1 to 3.0mm or one kind or plural kinds of nearly elliptic shapes of a major axis length 0.5 to 30.0mm, minor axis length 0.4 to 25.0mm and depth 0.1 to 3.0mm. As a result, the peeling of boundary layers is sufficiently delayed and the air resistance is effectively lowered at the time of swinging the racket. |
