Golf Club Head With Sole Compliance Zone

Abstract

A golf club head with a sole having a low stiffness compliance zone, which allows the face to deflect downward upon impact with a golf ball, is disclosed herein. The compliance zone comprises a plurality of through openings that are filled with one or more filler pieces comprising a low modulus material, all of which are located within three inches of a face section measured along a front-to-back axis of the golf club head.

We claim as our invention the following: 
     
         1 . A golf club head comprising:
 a body comprising a compliance zone on a sole section and located within three inches of a face portion measured along a front-to-back x-axis, wherein the compliance zone comprises a plurality of through-openings; and   a secondary filler piece comprising a base portion and a plurality of extensions, wherein each of the plurality of extensions extends from the base portion, and wherein each of the plurality of extensions fills one of the plurality of through-openings.   
     
     
         2 . The golf club head of  claim 1  wherein at least one of the plurality of through-openings is circular. 
     
     
         3 . The golf club head of  claim 1  wherein the plurality of through-openings comprises twenty through-openings. 
     
     
         4 . The golf club head of  claim 1  wherein the golf club head is a fairway wood-type golf club head. 
     
     
         5 . The golf club head of  claim 1  wherein the secondary filler piece comprises an inner portion and a cover piece, wherein the inner piece is composed of a high-density material, and wherein the cover piece is composed of a material having a lower density than the high density material. 
     
     
         6 . The golf club head of  claim 5  wherein the inner portion is metal injection molded. 
     
     
         7 . The golf club head of  claim 5  wherein the cover piece is overmolded over the inner portion. 
     
     
         8 . The golf club head of  claim 5  wherein the cover piece comprises each of the plurality of extensions. 
     
     
         9 . The golf club head of  claim 1  wherein the plurality of through-openings is disposed proximate to and is aligned parallel with the face opening. 
     
     
         10 . The golf club head of  claim 1  wherein the plurality of through-holes vary in shape, size, and length across the compliance zone. 
     
     
         11 . The golf club head of  claim 1  wherein the compliance zone comprises a variable thickness ranging from 0.01 inch to 0.05 inch. 
     
     
         12 . The golf club head of  claim 1  wherein the body is composed of a metal material, and wherein a crown insert is composed of a non-metal material.