| 摘要 |
<p>The racket string (2) is of a synthetic material with depressions (1) in diametrically opposite surfaces, made by passing it between pairs of wheels (5, 6; 7, 8), with one wheel in each pair having a toothed edge. As the string passes between the wheels and round idling pulleys (3, 4) at a speed of 60 - 200 m per minute, depressions are made in opposite surfaces. The racket string (2) is of a synthetic material with depressions (1) in diametrically opposite surfaces, made by passing it between pairs of wheels (5, 6; 7, 8), with one wheel in each pair having a toothed edge. As the string passes between the wheels and round idling pulleys (3, 4) at a speed of 60 - 200 m per minute, depressions are made in opposite surfaces e.g. to a depth of 0.05 mm and at 4 mm intervals for a string of 1.4 mm diameter.</p> |
