| 摘要 |
<p>PURPOSE: To prevent slice with long irons and hook with short irons by providing swing-direction marks on each face, making the marks incline toward the toe as they extend downwards in the case of long irons and toward the heel in the case of short irons, and making the marks approximately perpendicular to the ground in the case of middle irons. CONSTITUTION: In each club of an iron-club set, vertical lines pointed vertically from the top 5 to the sole 3 are provided on the toe side 2 and the heel side 4 of scoring lines 8, to form marks 9. The portion surrounded by the marks 9, the top 5 and the sole 3 is formed into the ball-striking area of the face 6, and a sweet spot (s) is set halfway between the toe 2 and the heel 4. The marks 9, when the head is placed on the surface of the ground to match lie angle, constitute straight lines which get closer to the toe 2 as they extend downward in the case of long irons; are approximately perpendicular to the surface of the ground in the case of middle irons; and get closer to the heel 4 in the case of short irons.</p> |
