Multi-material golf club head

Abstract

According to some examples, a golf club head includes a striking face; a sole; and a crown, the crown having an areal density of less than 1,000 g/m 2 and made from a structure including: an inner layer, a middle layer in contact with the inner layer, and an outer layer in contact with the middle layer, wherein the crown has a D Score of at least 1.3.

What is claimed is: 
     
         1 . A golf club head comprising:
 a striking face;   a sole; and   a crown, the crown having an areal density of less than 1,000 g/m 2  and made from a structure comprising:
 an inner layer, 
 a middle layer in contact with the inner layer, and 
 an outer layer in contact with the middle layer, 
   wherein the crown has a D Score of at least 1.3.   
     
     
         2 . The golf club head of  claim 1 , wherein the D Score of the crown is at least 1.5. 
     
     
         3 . The golf club head of  claim 1 , wherein the D Score of the crown is at least 1.6. 
     
     
         4 . The golf club head of  claim 1 , wherein the structure comprises at least 70% of the crown. 
     
     
         5 . The golf club head of  claim 1 , wherein the inner layer has a cutout opening. 
     
     
         6 . The golf club head of  claim 1 , wherein the middle layer comprises a foamed material and has a thickness greater than each of a thickness of the inner layer and a thickness of the outer layer. 
     
     
         7 . The golf club head of  claim 6 , wherein the middle layer comprises a foamed polymer, a foamed graphite, a foamed aluminum, a balsa wood, a graphitic foam, a liquid crystalline polymer foam, or a microcellular carbon. 
     
     
         8 . The golf club head of  claim 6 , wherein at least one of the inner layer or the outer layer comprises a carbon-fiber material, a thermoplastic composite material, a thermoset material, a solid polymer, a metal, or a super wood. 
     
     
         9 . A golf club head comprising:
 a striking face;   a sole; and   a crown, the crown having an areal density of less than 1000 g/m 2  and made from a structure comprising:
 an inner layer; 
 a middle layer in contact with the inner layer; and 
 an outer layer in contact with the middle layer, wherein a distance between an interior surface of the inner layer and an exterior surface of the outer layer is at least 0.8 mm, 
   wherein the amount of deflection of the crown as a function of mass of the crown is governed by the following equation when subjected to a downward force of 20 MPA at a geometric enter of the crown: Deflection≤−0.3177 (mass)+5.615.   
     
     
         10 . The golf club head of  claim 9 , wherein a thickness of the middle layer is at least 0.6 mm. 
     
     
         11 . The golf club head of  claim 10 , wherein a thickness of the inner layer is less than about 0.2 mm. 
     
     
         12 . The golf club head of  claim 11 , wherein a thickness of the outer layer is less than about 0.2 mm. 
     
     
         13 . The golf club head of  claim 12 , wherein the distance between the interior surface of the inner layer and the exterior surface of the outer layer is at least 2.5 mm. 
     
     
         14 . The golf club head of  claim 9 , wherein the crown has a D Score of at least 1.3. 
     
     
         15 . A golf club head comprising:
 a striking face;   a sole; and   a crown having an areal density of less than 1000 g/m 2  and comprising a structure, the structure comprising a plurality of layers having a thickness of at least 0.8 mm and comprising:
 a first layer comprising a first material and having a first areal density, and 
 a second layer on the first layer, comprising a second material different from the first material, and having a second areal density greater than the first areal density. 
   
     
     
         16 . The golf club head of  claim 15 , wherein the second layer is an outer layer having an exterior surface that defines at least part of an exterior surface of the crown. 
     
     
         17 . The golf club head of  claim 16 , wherein the second layer is directly on the first layer. 
     
     
         18 . The golf club head of  claim 16 , wherein the plurality of layers comprise a third layer between the first layer and the second layer and having a third areal density between the first areal density and the second areal density. 
     
     
         19 . The golf club head of  claim 16 , wherein the plurality of layers comprise a third layer between the first layer and the second layer, the third layer comprising a third material different from the first and second materials and having a thickness greater than each of a thickness of the first layer and a thickness of the second layer. 
     
     
         20 . The golf club head of  claim 15 , wherein the first material includes a foamed material, and the first layer has a thickness of at least 0.6 mm.