| 摘要 |
PURPOSE:To improve the strength of a tennis racket without increasing its weight by increasing the amt. of reinforcing fibers in the top part of the racket which is liable to be broken by receiving load. CONSTITUTION:The sectional shape in the top part of the frame 12 is set at a thickness W1 in an intra-surface direction within a range of 12 to 17mm and a relation W2/W1 between the thickness W1 in the intra-surface direction and the thickness W2 in an out-of-surface direction within 100 to 170%. The thickness W2 in the out-of-surface direction is set at a range of 22 to 32mm in a range of 30 deg. in a shaft direction from the side part and the relation of the circumferential length of the section of the top part with the circumferential length of the section of the part is so set as to made approximately the same within a range of 90 to 110% of L2/L1. |
