High loft, low center-of-gravity golf club heads

Abstract

A golf club and golf club head having a high static loft angle, low forward center of gravity, and enhanced z-axis gear effect via a large roll radius and/or tightly controlled moment of inertia about the CG x-axis, Ixx, associated with upward and downward twisting of the club head.

1 . A golf club head, comprising:
 a club head body having an external surface with a heel portion, a toe portion, a crown portion, a sole portion, a skirt portion positioned around a periphery between the sole portion and crown portion, a ball striking face having a thickness, and a hosel integrally formed with the club head body and extending outward from the club head body proximate to a crown and heel transition region;   wherein the ball striking face of the club head body has a geometric center;   wherein the crown portion has one or more openings, and wherein one or more corresponding crown panels are placed in the one or more openings, the crown panels having a first material density and a first portion thickness;   wherein a portion of the club head body located below a geometric center of the ball striking face is formed of a second material having a second material density and a second portion thickness, wherein the second material density is at least twice the first material density of the crown panels;   wherein at least a portion of the ball striking face is formed of a composite material; wherein a moment of inertia about the golf club head center-of-gravity x-axis, I xx , is between 250-800 kg-mm 2 ;   wherein the golf club head has a Delta 1 between 10 to 25 mm;   where a club head has a club head volume of at least 250 cm 3  and a club head weight of between about 190 and 210 grams; and   wherein the golf club head has a center of gravity that is below the geometric center of the ball striking face of the golf club head as measured along a z-axis of the golf club head having an origin at the geometric center.   
     
     
         2 . The golf club head of  claim 1 , wherein the center of gravity of the golf club head is 5-20 mm below the geometric center of the ball striking face of the golf club head as measured along a z-axis of the golf club head having an origin at the geometric center. 
     
     
         3 . The golf club head of  claim 2 , wherein the club head body has a center of gravity whose projection onto the ball striking face of the club head body is located off-center from the geometric center in a direction toward the sole portion. 
     
     
         4 . The golf club head of  claim 1 , wherein the sole portion is at least partially formed of a material that is denser than the material used to form the crown portion. 
     
     
         5 . The golf club head of  claim 4 , wherein the one or more crown panels are formed of a composite material. 
     
     
         6 . The golf club head of  claim 5 , wherein the ball striking face having a varying thickness of no less than 2.5 mm. 
     
     
         7 . The golf club head of  claim 6 , wherein the ball striking face having a varying thickness of no greater than 5 mm. 
     
     
         8 . The golf club head of  claim 1 , wherein the first material density has a density of approximately 2.8 g/cc or less. 
     
     
         9 . The golf club head of  claim 1 , wherein the first material density and the at least a portion of the ball striking face formed of composite material have a density of approximately 1.5 g/cc. 
     
     
         10 . The golf club head of  claim 1 , wherein the second material is formed of a titanium alloy. 
     
     
         11 . The golf club head of  claim 1 , wherein the second material is formed of a steel alloy. 
     
     
         12 . The golf club head of  claim 1 , wherein the club head body is formed from a combination of an alloy of titanium, an alloy of aluminum, and a composite material. 
     
     
         13 . The golf club head of  claim 1 , wherein the crown panels, the skirt, and ball striking face are held in place by adhesive bonding. 
     
     
         14 . The golf club head of  claim 12 , wherein the crown panels, the skirt, and ball striking face are held in place by adhesive bonding. 
     
     
         15 . A golf club head, comprising:
 a club head body having an external surface with a heel portion, a toe portion, a crown portion, a sole portion, a skirt portion positioned around a periphery between the sole portion and crown portion, a ball striking face having a thickness, and a hosel integrally formed with the club head body and extending outward from the club head body proximate to a crown and heel transition region;   wherein the ball striking face of the club head body has a geometric center;   wherein the crown portion has one or more openings, and wherein one or more corresponding crown panels are placed in the one or more openings, the crown panels having a first material density and a first portion thickness;   wherein a portion of the club head body located below a geometric center of the ball striking face is formed of a second material having a second material density and a second portion thickness, wherein the second material density is at least twice the first material density of the crown panels;   wherein a moment of inertia about a golf club head center-of-gravity x-axis, I xx , is between 250-800 kg-mm 2 ;   wherein the golf club head has a Delta 1 between 10 to 25 mm;   where the club head has a club head volume of at least 250 cm 3  and a club head weight of between about 190 and 210 grams;   wherein the club head body is formed from a combination of an alloy of titanium, an alloy of aluminum, and a composite material;   wherein the crown panels and the skirt are held in place by adhesive bonding;   wherein the ball striking face having a varying thickness no more 5 mm;   wherein the ball striking face having a roll radius of 300 mm or greater; and   wherein the golf club head has a center of gravity that is below the geometric center of the ball striking face of the golf club head as measured along a z-axis of the golf club head having an origin at the geometric center.   
     
     
         16 . The golf club head of  claim 15 , wherein the club head volume is at least 460 cm 3  or greater. 
     
     
         17 . The golf club head of  claim 15 , wherein the golf club head has a center of gravity that is 5-20 mm below the geometric center of the ball striking face of the golf club head as measured along a z-axis of the golf club head having an origin at the geometric center. 
     
     
         18 . The golf club head of  claim 15 , wherein the club head body has a center of gravity whose projection onto the ball striking face of the club head body is located off-center from the geometric center in a direction toward the sole portion. 
     
     
         19 . The golf club head of  claim 15 , wherein the sole portion is at least partially formed of a material that is denser than the material used to form the crown portion. 
     
     
         20 . The golf club head of  claim 16 , wherein at least a portion of the ball striking face is formed of a composite material.