Patent ID: 8951141
Filing Date: 2015-02-10
Classification: A63B

Abstract:
1. An iron-type golf club set comprising three or more iron-type golf clubs with cub heads having different loft angles such that the loft angles are gradually increased from the lowest numbered golf club therein having the smallest loft angle to the highest numbered golf club therein having the largest loft angle, wherein coefficients of inertia (A) of the club heads are gradually increased with the increase in the loft angle, and the difference (An−A wherein: the coefficient of inertia (A) of the club head is the ratio Ms/M of a moment of inertia Ms (gram sq·cm) of the club head around a horizontal axis extending in a toe-heel direction of the club head passing through the center of gravity of the club head, to the mass M (g) of the club head, each of the club heads comprises a head main body having, on its front side, a club face for hitting a golf ball, the head main body is provided on its back side with a top side protruding part protruding backward so that the top side protruding part has thicknesses of the top side protruding parts of the club heads are gradually increased with the increase in the loft angle when each said thickness is measured as the difference Ho−Hi between a maximum height Ho of the outer peripheral surface and a maximum height Hi of the inner peripheral surface in the rear view of the club head in its standard state.