Iron golf club head with improved performance

Abstract

An iron type golf club head with improved performance is disclosed herein. More specifically, the present invention discloses an iron type golf club head having a frontal face portion made out of a lightweight material that is separate and distinct from the material used to form the remaining body portion of the iron type golf club head. The thinner material allows the frontal face portion of the iron type golf club head to be made thinner, yielding improved performance characteristics such as a higher Coefficient of Restitution (COR) of greater than about 0.770 and a lower primary resonant frequency of less than about 5,000 Hertz.

What is claimed is: 
     
         1 . An iron type golf club head comprising:
 a frontal face portion, made out of a first material having a first density, connected to a forward portion of said iron type golf club head;   a body portion, made out of a second material having a second density, connected to a rear portion of said frontal face portion providing a structural support for said frontal face portion;
 wherein said first material is different from said second material; 
 wherein said first density is lower than said second density; and 
 wherein said iron type golf club head has a face replacement ratio of greater than about 0.9 and less than about 1.0; 
   wherein said face replacement ratio is calculated by dividing a cross-sectional height of said frontal face portion by a total cross-sectional height of a striking surface of said iron type golf club head; and   wherein a primary resonant frequency of said iron type golf club head is less than about 5,000 Hertz.   
     
     
         2 . The iron type golf club head of  claim 1 , wherein a COR of said iron type golf club head is greater than about 0.770. 
     
     
         3 . The iron type golf club head of  claim 2 , wherein said COR of said iron type golf club head is greater than about 0.773. 
     
     
         4 . The iron type golf club head of  claim 3 , wherein said COR of said iron type golf club head is greater than about 0.775. 
     
     
         5 . The iron type golf club head of  claim 1 , wherein said primary resonant frequency of said iron type golf club head is less than about 4,500 Hertz. 
     
     
         6 . The iron type golf club head of  claim 5 , wherein said primary resonant frequency of said iron type golf club head is less than about 4,300 Hertz. 
     
     
         7 . The iron type golf club head of  claim 1 , wherein a thickness of said frontal face portion is less than about 3.5 mm. 
     
     
         8 . The iron type golf club head of  claim 7 , wherein said thickness of said frontal face portion is less than about 3.0 mm. 
     
     
         9 . The iron type golf club head of  claim 8 , wherein said thickness of said frontal face portion is less than about 2.5 mm. 
     
     
         10 . The iron type golf club head of  claim 1 , wherein said iron type golf club head has a face replacement ratio of greater than about 0.925 and less than about 1.0. 
     
     
         11 . The iron type golf club head of  claim 10 , wherein said iron type golf club head has a face replacement ratio of greater than about 0.95 and less than about 1.0. 
     
     
         12 . An iron type golf club head comprising:
 a frontal face portion, made out of a first material having a first density, connected to a forward portion of said iron type golf club head; and   a body portion, made out of a second material having a second density, connected to a rear portion of said frontal face portion providing a structural support for said frontal face portion;   wherein said first material is different from said second material;   wherein said first density is lower than said second density;   wherein said frontal face portion comprises a striking surface and a rear surface, said rear surface opposite said striking surface;   wherein said body portion comprises a protrusion extending towards said rear surface, said protrusion comprising a front surface substantially parallel to said rear surface, said front surface offset from said rear surface;   wherein said front surface is substantially flat and extends further toward said rear surface than any other portion of said protrusion.   
     
     
         13 . The iron type golf club head of  claim 12 , wherein a primary resonant frequency of said iron type golf club head is less than about 5,000 Hertz. 
     
     
         14 . The iron type golf club head of  claim 13 , wherein said primary resonant frequency of said iron type golf club head is less than about 4,500 Hertz. 
     
     
         15 . The iron type golf club head of  claim 14 , wherein said primary resonant frequency of said iron type golf club head is less than about 4,300 Hertz. 
     
     
         16 . The iron type golf club head of  claim 12 , wherein said protrusion comprises a substantially flat bottom surface offset from a sole of said golf club head. 
     
     
         17 . An iron type golf club head comprising:
 a frontal face portion, made out of a first material, connected to a forward portion of said iron type golf club head;   a body portion, made out of a second material, connected to a rear portion of said frontal face portion providing a structural support for said frontal face portion;
 wherein said first material is different from said second material; 
 wherein said iron type golf club head has a face replacement ratio of greater than about 0.9 and less than about 1.0; 
   wherein said face replacement ratio is calculated by dividing a cross-sectional height of said frontal face portion by a total cross-sectional height of a striking surface of said iron type golf club head.   
     
     
         18 . The iron type golf club head of  claim 17 , wherein said frontal face portion comprises a striking surface and a rear surface, said rear surface opposite said striking surface, wherein said body portion comprises a protrusion extending towards said rear surface, said protrusion comprising a front surface substantially parallel to said rear surface, said front surface offset from said rear surface. 
     
     
         19 . The iron type golf club head of  claim 18 , wherein said front surface is substantially flat and extends further toward said rear surface than any other portion of said protrusion. 
     
     
         20 . The iron type golf club head of  claim 18 , wherein said protrusion comprises a substantially flat bottom surface offset from a sole of said golf club head.