| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an iron golf club head which allows an increase in the number of spins of a ball while adapting to the revised rules of R&A. <P>SOLUTION: The iron golf club head is provided with a groove 20 including: a first sidewall 21 leading to a face surface 11; a second sidewall 22 leading to the first sidewall 21; and a bottom 23 leading to the second sidewall 22. The width W1 of the groove 20 measured by a 30°measurement method is 0.76-0.88 mm. At the connection portion 24 of the face surface 11 and the first sidewall 21, roundness having a curvature radius R of 0.05-0.3 mm is formed. At the connection portion 25 of the first sidewall 21 and the second sidewall 22, roundness is formed. The depth D1 from the face surface 11 to the bottom 23 is 0.38-0.50 mm. The tilt angleθ1 of the first sidewall 21 with respect to the surface perpendicular to the face surface 11 is 36°-40°. The tilt angleθ2 of the second sidewall 22 with respect to the surface perpendicular to the face surface 11 is 5°-10°. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
