Golf club head with lightweight shaft-receiving structure

Abstract

A golf club head with a lightweight shaft-receiving structure is described herein. The lightweight shaft-receiving structure comprises one or more lightweight components provided in low-stress areas of the club head, wherein the lightweight components form portions of the shaft-receiving structure that would otherwise be formed by higher-density body material. The lightweight shaft-receiving structure creates discretionary mass that can be redistributed to improve the club head mass properties.

What is claimed is: 
     
         1 . A golf club head comprising:
 a strike face and a body;   the body comprising a crown, a sole opposite the crown, a heel, a toe opposite the heel, a skirt adjoining the crown and the sole, and a shaft-receiving structure;   and wherein the strike face, crown, sole, heel, toe, and skirt cooperate to surround an interior cavity;   the shaft-receiving structure comprising a hosel and a shaft sleeve;   wherein the crown comprises a transition to the hosel connecting the hosel to the crown;   wherein the hosel comprises a hosel wall forming at least a first portion of a hosel bore, a hosel wall upper portion forming a hosel bore opening, and a hosel base opposite the hosel bore opening, the hosel base formed at a sole interior surface, near the heel;   the hosel defines a hosel bore axis concentric with the hosel bore;   the shaft sleeve is insertable into the hosel through the hosel bore opening and configured to couple a golf club shaft with the hosel;   wherein the hosel bore opening is configured to receive the shaft sleeve; and   wherein a hosel wall extension at least partially protrudes into the interior cavity.   
     
     
         2 . The golf club head of  claim 1 , wherein the shaft-receiving structure further comprises a shaft-receiving structure length, measured parallel to the hosel bore axis from the hosel bore opening to the hosel base. 
     
     
         3 . The golf club head of  claim 1 , wherein a lip is formed at a hosel wall upper portion bottom end;
 the lip is formed by a change in thickness between the hosel wall upper portion and a remainder of the hosel wall; and   wherein the hosel wall upper portion comprises a greater thickness than the remainder of the hosel wall.   
     
     
         4 . The golf club head of  claim 1 , wherein the shaft-receiving structure further comprises a securing fastener configured to couple a shaft sleeve bottom end to secure the shaft sleeve in the hosel. 
     
     
         5 . The golf club head of  claim 4 , wherein the securing fastener comprises a bolt with a bolt head and a bolt body;
 the hosel comprises a hosel bottom surface with a passageway therethrough to accommodate passage of the bolt body into the hosel bore while retaining the bolt head external to the hosel bore;   the shaft sleeve bottom end is configured to engage the bolt body via a screw thread mechanism; and   the screw thread mechanism is configured to pull the shaft sleeve towards the hosel bottom surface and seat a sleeve top coupler against a hosel top coupler.   
     
     
         6 . The golf club head of  claim 4 , wherein the shaft sleeve comprises:
 a shaft bore configured to receive an end of a golf club shaft;   a sleeve axis extending along a centerline of the shaft sleeve from a sleeve top end to a sleeve bottom end; and   a sleeve outer wall wherein at least portions of the sleeve outer wall are substantially parallel to the sleeve axis.   
     
     
         7 . The golf club head of  claim 6 , wherein the portions of the sleeve outer wall substantially parallel to the sleeve axis comprises a first sleeve outer diameter;
 wherein a sleeve outer wall lower portion adjacent the sleeve bottom end is not parallel to the sleeve axis but tapers to the sleeve bottom end; and   wherein the sleeve bottom end comprises a second sleeve outer diameter smaller than the first sleeve outer diameter.   
     
     
         8 . The golf club head of  claim 7 , wherein the first sleeve outer diameter is in a range of 0.423 inch to 0.427 inch; and
 wherein the second sleeve outer diameter is in a range of 0.323 inch to 0.327 inch.   
     
     
         9 . The golf club head of  claim 6 , wherein the shaft sleeve comprises a shaft sleeve length; and
 wherein the shaft sleeve length is in a range of 1.547 inches to 1.555 inches.   
     
     
         10 . The golf club head of  claim 6 , wherein the shaft sleeve bottom end further comprises a bottom end threaded bore; and
 wherein the bottom end threaded bore is not in communication with the shaft sleeve bore, but is a threaded, blind hole.   
     
     
         11 . The golf club head of  claim 10 , wherein the bottom end threaded bore comprises a threaded bore length; and
 wherein the threaded bore length is in a range of 0.290 inch to 0.294 inch.   
     
     
         12 . The golf club head of  claim 1 , wherein the hosel wall extension comprises a partial cylinder extending from the hosel bore to the hosel base; and
 wherein the partial cylinder protrudes from a heel interior surface.   
     
     
         13 . The golf club head of  claim 12 , wherein the partial cylinder is configured to receive the shaft sleeve, partially surrounding the shaft sleeve. 
     
     
         14 . The golf club head of  claim 12 , wherein the partial cylinder comprises a rib wall protruding in the interior cavity with a rib wall maximum height measured from the heel interior surface toward a most inward portion of the partial cylinder. 
     
     
         15 . The golf club head of  claim 14 , wherein the rib wall maximum height is in a range of 0.95 inch to 1.05 inches. 
     
     
         16 . The golf club head of  claim 1 , wherein the hosel wall extension comprises a right circular hollow cylinder protruding soleward parallel to the hosel bore axis, lengthening the hosel bore such that a lower edge of the right circular hollow cylinder is suspended within the interior cavity; and
 wherein a right circular hollow cylinder sidewall partially forms a heel interior surface, and a free wall portion partially that projects into the interior cavity.   
     
     
         17 . The golf club head of  claim 16 , wherein the free wall portion comprises a free wall length measured from a free wall attachment point to a right circular hollow cylinder sidewall lower edge parallel to the hosel bore axis; and
 wherein the free wall length is in a range of 0.30 inch to 0.68 inch.   
     
     
         18 . The golf club head of  claim 17 , wherein a separation distance is measured between the right circular hollow cylinder sidewall lower edge and a hosel base upper surface parallel to the hosel bore axis; and
 wherein the separation distance is in a range between 0.25 inch to 1.0 inch.   
     
     
         19 . The golf club head of  claim 17 , wherein the shaft-receiving structure comprises a shaft-receiving structure total length measured from an upper side of the hosel base to a hosel bore opening uppermost edge and parallel to the hosel bore axis; and
 wherein the shaft-receiving structure length is in a range of 1.60 inches to 1.72 inches.   
     
     
         20 . The golf club head of  claim 19 , wherein a ratio of a separation distance to the shaft-receiving structure total length is in a range of 0.15 to 1.70.