Golf club head

Abstract

A golf club head is disclosed, which enables a low center of gravity to be achieved without spoiling appearance of the head and reducing strength thereof, and thus enables a carry to be increased. This golf club head has a hollow structure, and includes an opening in a crown portion and a plate member fixed to the opening. The plate member is made of a material having a specific strength of 294 N/mm 2 or higher. For example, this head includes a volume equal to or more than 350 cc, a center-of-gravity retreating amount GR from a shaft axis equal to or more than 15 mm, and a center-of-gravity position ratio GH/FH equal to or lower than 0.61. Here, the ratio GH/FH is calculated from a maximum height FH of a face surface and a center-of-gravity height GH on the face surface.

What is claimed is:  
     
         1 . A golf club head having a hollow structure, comprising: 
 a crown portion;    an opening in the crown portion; and    a plate member fixed to the opening, the plate member being made of a material having a specific strength of 294 N/mm 2  or higher.    
     
     
         2 . A golf club head having a hollow structure, the head including: 
 a volume equal to or more than 350 cc;    a center-of-gravity retreating amount GR from a shaft axis equal to or more than 15 mm; and    a center-of-gravity position ratio GH/FH equal to or lower than 0.61, the ratio GH/FH being calculated from a maximum height FH of a face surface and a center-of-gravity height GH on the face surface.    
     
     
         3 . A golf club head having a hollow structure, the head including: 
 a volume equal to or more than 300 cc but less than 350 cc;    a center-of-gravity retreating amount GR from a shaft axis equal to or more than 18 mm; and    a center-of-gravity position ratio GH/FH equal to or lower than 0.55, the ratio GH/FH being calculated from a maximum height FH of a face surface and a center-of-gravity height GH on the face surface.    
     
     
         4 . A golf club head having a hollow structure, the head including: 
 a volume equal to or more than 150 cc but less than 200 cc;    a center-of-gravity retreating amount GR from a shaft axis equal to or more than 12 mm; and    a center-of-gravity position ratio GH/FH equal to or lower than 0.50, the ratio GH/FH being calculated from a maximum height FH of a face surface and a center-of-gravity height GH on the face surface.    
     
     
         5 . A golf club head having a hollow structure, the head including: 
 a volume equal to or more than 100 cc but less than 150 cc;    a center-of-gravity retreating amount GR from a shaft axis equal to or more than 8 mm; and    a center-of-gravity position ratio GH/FH equal to or lower than 0.50, the ratio GH/FH being calculated from a maximum height FH of a face surface and a center-of-gravity height GH on the face surface.    
     
     
         6 . The golf club head according to any one of  claims 2  to  5 , wherein an opening is provided in a crown portion, and a plate member made of a material having a specific strength of 294 N/mm 2  or higher is fixed to the opening.  
     
     
         7 . The golf club head according to  claim 1 , wherein a surface area ratio of the plate member to a portion above a position at half a maximum height of the crown portion is set equal to or higher than 20%.  
     
     
         8 . The golf club head according to  claim 6 , wherein a surface area ratio of the plate member to a portion above a position at half a maximum height of the crown portion is set equal to or higher than 20%.