Multi-material golf club head

Abstract

A multi-material golf club head having an improved performance is disclosed. More specifically, the present invention relates to a multi-material golf club head having a metallic frontal striking face portion and aft body portion with a crown opening and a sole opening that are covered by a composite crown sub-shell and a composite sole sub-shell, respectively.

What is claimed is: 
     
         1 . A golf club head, comprising:
 a) a crown, a sole opposite the crown, a front side adjacent to the crown and the sole, a back side opposite the front side and adjacent to the crown and the sole, a heel adjacent to the crown, the sole, the front side, and the back side, a toe opposite the heel and adjacent to the crown, the sole, the front side, and the back side;   b) a stainless steel ring shell having a striking face portion at the front side of the golf club, and an aft body portion behind the striking face portion and extending to the back side, wherein the striking face portion defines a face center;   c) a crown opening at a top side of the aft body portion, the crown opening having a crown opening area of about 5500 mm 2  to about 9500 mm 2 ;   d) a sole opening at a bottom side of the aft body portion, the sole opening having a sole opening area of about 1500 mm 2  to about 5500 mm 2 , the sole opening located on a toe-side of the aft body portion;   e) a crown sub-shell configured to cover the crown opening, wherein a density of the crown sub-shell is about 0.5 g/cm 3  to about 5 g/cm 3 , an area of the crown sub-shell is about 6500 mm 2  to about 10,500 mm 2 , and a thickness of the crown sub-shell is about 0.3 mm to about 0.9 mm; and   f) a sole sub-shell configured to cover the sole opening, wherein a density of the sole sub-shell is about 0.5 g/cm 3  to about 5 g/cm 3 , an area of the sole sub-shell is about 3000 mm 2  to about 7000 mm 2 , and a thickness of the sole sub-shell is about 0.5 mm to about 1.5 mm,   g) wherein a center of gravity of the golf club head is less than about 32.5 mm behind the face center in a front side to back side direction, and the center of gravity of the golf club head is greater than about 4.8 mm below the face center in a top side to bottom side direction.   
     
     
         2 . The golf club head of  claim 1 , wherein a size of the golf club head is larger than 300 cc, and a mass of the ring shell is about 130 grams to about 170 grams. 
     
     
         3 . The golf club head of  claim 2 , wherein a ratio of the area of the crown sub-shell to the thickness of the crown sub-shell is about 11,000:1 to about 18,000:1. 
     
     
         4 . The golf club head of  claim 2 , wherein a ratio of the density of the crown sub-shell to the thickness of the crown sub-shell is about 2.8:1 to about 6:1. 
     
     
         5 . The golf club head of  claim 2 , wherein a ratio of the area of the crown sub-shell to the density of the crown sub-shell is about 2600:1 to about 4500:1. 
     
     
         6 . The golf club head of  claim 2 , wherein a ratio of the area of the sole sub-shell to the thickness of the sole sub-shell is about 3600:1 to about 6900:1. 
     
     
         7 . The golf club head of  claim 2 , wherein a ratio of the density of the sole sub-shell to the thickness of the sole sub-shell is about 1.8:1 to about 3.8:1. 
     
     
         8 . The golf club head of  claim 2 , wherein a ratio of the area of the sole sub-shell to the density of the sole sub-shell is 1300:1 to about 2800:1. 
     
     
         9 . The golf club head of  claim 2 , wherein a ratio of the thickness of the sole sub-shell to the thickness of the crown sub-shell is about 1.1:1 to about 2.6:1. 
     
     
         10 . The golf club head of  claim 2 , wherein a ratio of the area of the crown sub-shell to the area of the sole sub-shell is about 1.4 to about 2.3. 
     
     
         11 . The golf club head of  claim 2 , wherein a ratio of the density of the sole sub-shell to the density of the crown sub-shell is 0.6:1 to about 1.5:1. 
     
     
         12 . The golf club head of  claim 2 , wherein the density of the crown sub-shell is about 2 g/cm 3  or less, wherein the density of the sole sub-shell is about 2 g/cm 3 , wherein the thickness of the crown sub-shell is about 0.6 mm, and wherein the thickness of the sole sub-shell is about 0.9 mm. 
     
     
         13 . A golf club head, comprising:
 a) a stainless steel ring shell having a striking face portion at a front of the golf club, and an aft body portion behind the striking face portion, wherein the striking face portion defines a face center, wherein the striking face portion comprises a striking face insert covering a front opening;   b) a crown opening at a top of the aft body portion, the crown opening having a crown opening area of about 5500 mm 2  to about 9500 mm 2 ;   c) a sole opening having a sole opening area of about 1500 mm 2  to about 5500 mm 2 , wherein the sole opening is located on a toe-side of the aft body portion;   d) a crown sub-shell configured to cover the crown opening, wherein a density of the crown sub-shell is about 0.5 g/cm 3  to about 5 g/cm 3 , an area of the crown sub-shell is about 6500 mm 2  to about 10,500 mm 2 , and a thickness of the crown sub-shell is about 0.3 mm to about 0.9 mm; and   e) a sole sub-shell configured to cover the sole opening, wherein a density of the sole sub-shell is about 0.5 g/cm 3  to about 5 g/cm 3 , an area of the sole sub-shell is about 3000 mm 2  to about 7000 mm 2 , and a thickness of the sole sub-shell is about 0.5 mm to about 1.5 mm,   f) wherein the center of gravity of the golf club head in a front side to back side direction is less than 32 mm from the face center, and the center of gravity of the golf club head is greater than about 4.8 mm below the face center in a top side to bottom side direction.   
     
     
         14 . The golf club head of  claim 13 ,
 a) wherein a ratio of the area of the crown sub-shell to the thickness of the crown sub-shell is about 11,000:1 to about 18,000:1,   b) wherein a ratio of the density of the crown sub-shell to the thickness of the crown sub-shell is about 2.8:1 to about 6:1,   c) wherein a ratio of the area of the crown sub-shell to the density of the crown sub-shell is about 2600:1 to about 4500:1.   
     
     
         15 . The golf club head of  claim 13 ,
 a) wherein a ratio of the area of the sole sub-shell to the thickness of the sole sub-shell is about 3600:1 to about 6900:1,   b) wherein a ratio of the density of the sole sub-shell to the thickness of the sole sub-shell is about 1.8:1 to about 3.8:1,   c) wherein a ratio of the area of the sole sub-shell to the density of the sole sub-shell is 1300:1 to about 2800:1.   
     
     
         16 . The golf club head of  claim 13 ,
 a) wherein a ratio of the thickness of the sole sub-shell to the thickness of the crown sub-shell is about 1.1:1 to about 2.6:1,   b) wherein a ratio of the area of the crown sub-shell to the area of the sole sub-shell is about 1.4 to about 2.3,   c) wherein a ratio of the density of the sole sub-shell to the density of the crown sub-shell is 0.6:1 to about 1.5:1.   
     
     
         17 . The golf club head of  claim 13 , wherein the density of the crown sub-shell is about 2 g/cm 3  or less, wherein the density of the sole sub-shell is about 2 g/cm 3 , wherein the thickness of the crown sub-shell is about 0.6 mm, and wherein the thickness of the sole sub-shell is about 0.9 mm. 
     
     
         18 . A golf club head, comprising:
 a) a crown, a sole opposite the crown, a front side adjacent to the crown and the sole, a back side opposite the front side and adjacent to the crown and the sole, a heel adjacent to the crown, the sole, the front side, and the back side, a toe opposite the heel and adjacent to the crown, the sole, the front side, and the back side;   b) a striking face portion at the front side, wherein the striking face portion is made of stainless steel, and wherein the striking face portion defines a face center; and   c) a composite aft body behind the striking face portion;   d) wherein a density of the composite aft body is about 0.5 g/cm 3  to about 5 g/cm 3 , and a thickness of the composite aft body is about 0.5 mm to about 1.5 mm,   e) wherein a size of the golf club head is larger than 300 cc, and a mass of the golf club head is less than about 200 grams,   f) wherein a center of gravity of the golf club head is less than 32 mm from the face center in a front side to back side direction.   
     
     
         19 . The golf club head of  claim 18 , wherein the center of gravity of the golf club head is greater than about 4.8 mm below the face center in a top side to bottom side direction. 
     
     
         20 . The golf club head of  claim 19 , wherein the center of gravity of the golf club head is less than 30 mm from the face center in the front side to back side direction, and the center of gravity of the golf club head is greater than about 5.0 mm below the face center in the top side to bottom side direction.