Golf club head

Abstract

This invention provides a hollow golf club head including a fixing member which includes a shaft body formed with a threaded portion at one end, and a head portion at the other end of the shaft body, a viscoelastic body having an opening through which the shaft body extends, a recess portion formed in a circumferential wall of the golf club head and in which the viscoelastic body is disposed, and a screw hole formed in a bottom portion of the recess portion and threadably engages with the threaded portion. The viscoelastic body is fixed between the head portion and the bottom portion by threadably engaging the threaded portion with the screw hole.

1 . A hollow golf club head comprising:
 a fixing member having a shaft body formed with a threaded portion at one end, and a head portion at the other end of said shaft body;   a viscoelastic body being flat and having a first opening through which said shaft body extends;   a recess portion formed in a circumferential wall of the golf club head and in which said viscoelastic body is disposed, said recess portion having a bottom portion which is in contact with one surface of said viscoelastic body;   a screw hole formed in said bottom portion and threadably engages with said threaded portion, and   an interposed member interposed between said viscoelastic body and said head portion and includes a second opening through which said shaft body extends, said interposed member covering the whole viscoelastic body and having a flat surface being in contact with the other surface of said viscoelastic body,   wherein said viscoelastic body is fixed between said interposed member and said bottom portion by threadably engaging said threaded portion with said screw hole,   a plurality of said recess portions formed in different portions in the circumferential wall,   said fixing member, said viscoelastic body, said screw hole and said interposed member provided to each of said recess portions, and   said viscoelastic bodies have different vibration damping performances with each other.   
   
   
       2 . The head according to  claim 1 , wherein said recess portion is formed in at least a sole portion of the golf club head. 
   
   
       3 . The head according to  claim 1 , wherein said recess portions are formed in a sole portion and a back-side side portion of the golf club head. 
   
   
       4 . A hollow golf club head comprising:
 a first recess portion formed in a portion of said head;   a second recess portion formed in another portion of said head;   a first viscoelastic body fixed in said first recess portion;   a second viscoelastic body fixed in said second recess portion and having vibration damping performance different from said first viscoelastic body;   a first cover member provided with said first recess portion and covering the whole first viscoelastic body; and   a second cover member provided with said second recess portion and covering the whole second viscoelastic body.   
   
   
       3 . The head according to  claim 4 , wherein said first recess portion is formed in a sole portion of said head, and said second recess portion is formed in a side portion of said head. 
   
   
       4 . The head according to  claim 4 , wherein said first recess portion is formed in a sole portion of said head.