Golf club head

Abstract

A face member of a golf club head includes first and second main ribs disposed inside thereof. The first main rib is extended from a crown side to a sole side and the second main rib is extended from a hosel side to a toe side of the sole. The first and the second main ribs intersect with each other at an intersection portion. Additionally, a first groove is provided from the intersection portion of the rib toward the sole side, and a second groove is provided from the intersection portion of the rib toward the toe side.

What is claimed is: 
     
         1 . A golf club head having a hollow internal structure, the golf club head comprising:
 a face portion having a hitting surface; and first and second main ribs disposed inside the face portion,   wherein the first main rib is extended from a crown side to a sole side and the second main rib is extended from a hosel side to a toe side of the sole, and the first and second main ribs intersect with each other at an intersection portion, and   the first and the second main ribs are so constructed that stiffness of the sole side is lower than that of the crown side.   
     
     
         2 . The golf club head according to  claim 1 , wherein a first groove is provided from the intersection portion of the first main rib up to the sole side, and the depth of the first groove is not more than about ¾ of the maximum height of the first main rib, and
 a second groove is provided from the intersection portion of the second main rib up to the toe side, and the depth of the second groove is not more than about ¾ of the maximum height of the second main rib. 
 
     
     
         3 . The golf club head according to  claim 1 , wherein the height of the first and second main rib is about 0.5 mm to about 1.5 mm. 
     
     
         4 . The golf club head according to  claim 1 , wherein the height of the first and second main ribs is smaller on the sole side than on the crown side. 
     
     
         5 . The golf club head according to  claim 1 , wherein the width of the first and second main ribs is about 8 mm to about 14 mm. 
     
     
         6 . The golf club head according to  claim 1 , further comprising:
 a reinforcement rib which is disposed inside the face portion and extends from the intersection portion toward an end of the face portion,   wherein the height of the reinforcement rib is decreased gradually from the intersection portion toward the end, and the reinforcement portion is formed part of the way to the end of the face portion.