| 摘要 |
<p>PURPOSE:To improve the knot breakage strength and improve durability in use by using an eccentrically flat thread having a ratio between the larger and shorter diameters over a prescribed value, at least in one part of a wound thread. CONSTITUTION:An eccentrically flat thread 21 having a ratio between the longer diameter A and the shorter diameter B on the sectional surface of 1.5 or more is used at least as one part of a wound thread 20. At this time, only the eccentrically flat thread 21 may be used, or a thread 22 having a circular section which is used for the gut of a racket can be used together with the eccentrically flat thread 21. The sectional shape of the eccentrically flat thread 21 is an elliptical form like a collapsed circle, rectangular, or a rectangular form having R at four corners. The ratio between the longer diameter A and the shorter diameter B within a range of 1.5 to 3.0 is preferable in viewpoint of the improvement of the knot breakage strength of the gut, manufacture of the gut, handling, etc. In case of the ratio less than 1.5, the improvement of the knot breakage strength is not sufficiently developed. The tensile elongation of the eccentrically flat thread 21 which is larger than that of a core thread 10 permits the sufficient extension of the wound thread 20 in the knot part, and the breakage of only the wound thread 20 is prevented, and the knot breakage strength can be improved.</p> |
