Golf club head

Abstract

A hollow golf club head comprises a face portion, a crown portion and a sole portion. The club face has a face center. In a vertical cross section of the head passing through the face center: a ratio Hf/H of a height Hf of the club face measured in parallel to a tangential line drawn passing the face center, to a maximum height H of the head measured in parallel to the tangential line is not more than 0.65; when measured at a first boundary point between the face portion's inner surface and the crown portion's inner surface, an inner surface of the head has a radius of curvature in a range from 4.0 to 10.0 mm; and when measured at the first boundary point from the inner surface to an outer surface of the head, a wall thickness of the head is not less than 1.5 mm.

1 . A golf club head having a hollow therein and comprising a face portion, a crown portion and a sole portion which enclose the hollow,
 the face portion having an outer surface forming a club face and an inner surface facing the hollow,   the crown portion having an inner surface facing the hollow, and   the club face having a face center, wherein   in a vertical cross section of the head passing through the face center,   
       (a) a ratio Hf/H of a height Hf of the club face measured in parallel to a tangential line drawn passing the face center, to a maximum height H of the head measured in parallel to the tangential line is not more than 0.65, 
       (b) when measured at a first boundary point between the face portion's inner surface and the crown portion's inner surface, an inner surface of the head has a radius of curvature in a range from 4.0 to 10.0 mm, and 
       (c) when measured at the first boundary point from the inner surface to an outer surface of the head, a wall thickness of the head is not less than 1.5 mm. 
     
     
         2 . The golf club head according to  claim 1 , wherein
 in a first region from the first boundary point to a first point which is at a distance of 10 mm from the first boundary point toward the crown portion, the crown portion has the smallest wall thickness at the first point.   
     
     
         3 . The golf club head according to  claim 2 , wherein
 from the first boundary point to the first point, the wall thickness of the crown portion decreases without increasing.   
     
     
         4 . The golf club head according to  claim 2 , wherein
 the wall thickness of the crown portion at the first point is not more than 1.0 mm.   
     
     
         5 . The golf club head according to  claim 1 , wherein
 the sole portion has an inner surface facing the hollow, and   in said vertical cross section of the head,   
       (d) a radius of curvature at a second boundary point between the inner surface of the face portion and the inner surface of the sole portion is 3.0 and 10.0 mm, and 
       (e) a wall thickness at the second boundary point is not less than 1.5 mm. 
     
     
         6 . The golf club head according to  claim 2 , wherein
 the sole portion has an inner surface facing the hollow, and   in said vertical cross section of the head,   
       (d) a radius of curvature at a second boundary point between the inner surface of the face portion and the inner surface of the sole portion is 3.0 and 10.0 mm, and 
       (e) a wall thickness at the second boundary point is not less than 1.5 mm. 
     
     
         7 . The golf club head according to  claim 4 , wherein
 the sole portion has an inner surface facing the hollow, and   in said vertical cross section of the head,   
       (d) a radius of curvature at a second boundary point between the inner surface of the face portion and the inner surface of the sole portion is 3.0 and 10.0 mm, and 
       (e) a wall thickness at the second boundary point is not less than 1.5 mm. 
     
     
         8 . The golf club head according to  claim 5 , wherein
 in a second region from the second boundary point to a second point which is at a distance of 15 mm from the second boundary point toward the sole portion, the sole portion has the smallest wall thickness at the second point.   
     
     
         9 . The golf club head according to  claim 6 , wherein
 in a second region from the second boundary point to a second point which is at a distance of 15 mm from the second boundary point toward the sole portion, the sole portion has the smallest wall thickness at the second point.   
     
     
         10 . The golf club head according to  claim 7 , wherein
 in a second region from the second boundary point to a second point which is at a distance of 15 mm from the second boundary point toward the sole portion, the sole portion has the smallest wall thickness at the second point.   
     
     
         11 . The golf club head according to  claim 8 , wherein
 from the second boundary point to the second point, the wall thickness of the sole portion decreases without increasing.   
     
     
         12 . The golf club head according to  claim 8 , wherein
 the wall thickness of the sole portion at the second point is not more than 1.0 mm.   
     
     
         13 . The golf club head according to  claim 9 , wherein
 the wall thickness of the sole portion at the second point is not more than 1.0 mm.   
     
     
         14 . The golf club head according to  claim 10 , wherein
 the wall thickness of the sole portion at the second point is not more than 1.0 mm.   
     
     
         15 . A golf club head having a hollow therein and comprising a face portion, a crown portion and a sole portion which enclose the hollow,
 the face portion having an outer surface forming a club face and an inner surface facing the hollow,   the sole portion having an inner surface facing the hollow, and   the club face having a face center, wherein   in a vertical cross section of the head passing through the face center,   
       (a) a ratio Hf/H of a height Hf of the club face measured in parallel to a tangential line drawn passing the face center, to a maximum height H of the head measured in parallel to the tangential line is not more than 0.65, 
       (d) a radius of curvature at a second boundary point between the inner surface of the face portion and the inner surface of the sole portion is 3.0 and 10.0 mm, and 
       (e) a wall thickness at the second boundary point is not less than 1.5 mm. 
     
     
         16 . The golf club head according to  claim 15 , wherein
 in a first region from the first boundary point to a first point which is at a distance of 10 mm from the first boundary point toward the crown portion, the crown portion has the smallest wall thickness at the first point.   
     
     
         17 . A golf club head having a hollow therein and comprising a face portion, a crown portion and a sole portion which enclose the hollow,
 the face portion having an outer surface forming a club face and an inner surface facing the hollow,   the crown portion having an inner surface facing the hollow, and   the club face having a face center,   
       wherein
 in a vertical cross section of the head passing through the face center, 
 
       (a) a ratio Hf/H of a height Hf of the club face measured in parallel to a tangential line drawn passing the face center, to a maximum height H of the head measured in parallel to the tangential line is not more than 0.65, 
       (b) when measured at a first boundary point between the face portion's inner surface and the crown portion's inner surface, an inner surface of the head has a radius of curvature in a range from 4.0 to 10.0 mm, and 
       (d) a radius of curvature at a second boundary point between the inner surface of the face portion and the inner surface of the sole portion is 3.0 and 10.0 mm. 
     
     
         18 . The golf club head according to  claim 1 , wherein
 the ratio Hf/H is not less than 0.50.   
     
     
         19 . The golf club head according to  claim 15 , wherein
 the ratio Hf/H is not less than 0.50.   
     
     
         20 . The golf club head according to  claim 17 , wherein
 the ratio Hf/H is not less than 0.50.