Golf club head

Abstract

A golf club head with a hollow therein includes a face portion and a main body portion including a crown portion and a sole portion extending rearward from the face portion. The main body portion is provided with a slit penetrating the main body portion to the hollow, and a surrounding area of the slit is at least partially provided with a thick portion. The slit is arranged so that at least part of the slit is visible in a front view of the golf club head under its reference state, where the reference state is such that the head is placed on a horizontal plane at a lie angle and a loft angle specified for the head, while keeping a shaft axis center line of the head on a reference vertical plane.

What is claimed is: 
     
         1 . A golf club head with a hollow therein, comprising:
 a face portion; and   a main body portion, the main body portion including a crown portion and a sole portion both extending backwardly of the head from the face portion,   
       wherein
 the main body portion is provided with a slit penetrating the main body portion to the hollow, and 
 a surrounding area of the slit is at least partially provided with a thick portion, wherein 
 the slit is arranged so that at least part of the slit is visible in a front view of the golf club head under its reference state, where the reference state is such that the head is placed on a horizontal plane at a lie angle and a loft angle specified for the head, while keeping a shaft axis center line of the head on a reference vertical plane. 
 
     
     
         2 . The golf club head according to  claim 1 , wherein
 the thick portion is formed annularly so as to surround the slit.   
     
     
         3 . The golf club head according to  claim 1 , wherein
 the thick portion includes an outside thick portion protruding toward the outside of the head.   
     
     
         4 . The golf club head according to  claim 1 , wherein
 the slit is provided in one of, or alternatively, each of the crown portion and the sole portion.   
     
     
         5 . The golf club head according to  claim 1 , wherein
 the slit is provided with a cover closing the slit.   
     
     
         6 . The golf club head according to  claim 1 , wherein
 the slit is provided in the crown portion, and   the slit is disposed in one of, or alternatively, each of a region on a toe side and a region on a heel side of a central region of the crown portion, wherein the central region is defined as extending 15 mm toward a toe of the head and toward a heel of the head from a straight line drawn parallel to a front-rear direction of the head passing through a face center in the top view of the head under its reference state.   
     
     
         7 . The golf club head according to  claim 1 , wherein
 the slit is provided in the sole portion, and   the slit is disposed in one of a central region, a region on a toe side of the central region and a region on a heel side of the central region, wherein the central region is defined as extending 15 mm toward a toe of the head and toward a heel of the head from a straight line drawn parallel to a front-rear direction of the head passing through a face center in the bottom view of the head under its reference state.   
     
     
         8 . A golf club head with a hollow therein, comprising:
 a face portion; and   a main body portion, the main body portion including a crown portion and a sole portion both extending backwardly of the head from the face portion,   
       wherein
 the main body portion is provided with a slit penetrating the main body portion to the hollow, and 
 a surrounding area of the slit is at least partially provided with a thick portion, wherein 
 the thick portion includes an inside thick portion protruding toward the hollow, and 
 the inside thick portion extends into the back surface of the face portion. 
 
     
     
         9 . The golf club head according to  claim 8 , wherein
 the inside thick portion is formed annularly so as to surround the slit.   
     
     
         10 . The golf club head according to  claim 8 , wherein
 the thick portion includes an outside thick portion protruding toward the outside of the head.   
     
     
         11 . The golf club head according to  claim 8 , wherein
 the slit is provided in one of, or alternatively, each of the crown portion and the sole portion.   
     
     
         12 . The golf club head according to  claim 8 , wherein
 the slit is provided with a cover closing the slit.   
     
     
         13 . The golf club head according to  claim 8 , wherein
 the slit is provided in the crown portion, and   the slit is disposed in one of, or alternatively, each of a region on a toe side and a region on a heel side of a central region of the crown portion, wherein the central region is defined as extending 15 mm toward a toe of the head and toward a heel of the head from a straight line drawn parallel to a front-rear direction of the head passing through a face center in the top view of the head under its reference state.   
     
     
         14 . The golf club head according to  claim 8 , wherein
 the slit is provided in the sole portion, and   the slit is disposed in one of a central region, a region on a toe side of the central region and a region on a heel side of the central region, wherein the central region is defined as extending 15 mm toward a toe of the head and toward a heel of the head from a straight line drawn parallel to a front-rear direction of the head passing through a face center in the bottom view of the head under its reference state.