Abstract:
An iron-type golf club head having a rear cavity with an undercut portion is disclosed herein. The undercut portion is present in less than 360 degrees of the rear cavity. Further, the undercut portion is preferably discontinuous. Further, the under portion preferably has sharp angles at segments of the rear cavity.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     The present application is a continuation application of U.S. patent application Ser. No. 12/875,294, filed on Sep. 3, 2010, which claims priority to U.S. Provisional Patent Application No. 61/243,852, filed on Sep. 18, 2009, now abandoned, both of which are hereby incorporated by reference in their entireties. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a golf club head. More specifically, the present invention relates to an iron-type golf club head having a rear cavity with an undercut portion. 
     2. Description of the Related Art 
     The prior art discloses iron-type golf club heads with undercuts. 
     Callaway Golf Company has sold iron-type golf club heads with a rear cavity having an undercut under the following product names: BIG BERTHA® irons; X-12® irons; HAWKEYE® irons; X-14® irons; X-16® irons; X-18® irons; X-20™ irons; X-22™ irons and others. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is an iron-type golf club head with a rear cavity having an undercut. 
     One aspect of the present invention is an iron-type golf club head comprising a body having a rear cavity with a non-continuous undercut portion. 
     Another aspect of the present invention is an iron-type golf club head comprising a body having a rear cavity with a sharp angle undercut portion. 
     Another aspect of the present invention is an iron-type golf club head comprising a body having a rear cavity with a non-curved undercut portion. 
     Another aspect of the present invention is an iron-type golf club head comprising a body having a rear cavity that is segmented into six straight sections. 
     Another aspect of the present invention is an iron-type golf club head comprising a body having a rear cavity with at least five sections of the six sections that have an undercut portion. 
     Another aspect of the present invention is an iron-type golf club head comprising a body having a rear cavity with at least four sections of the six sections that have an undercut portion. 
     Another aspect of the present invention is an iron-type golf club head comprising a body having a rear cavity with an undercut portion of 295 degrees, wherein a total perimeter of a rear cavity is 7.8 inches and an undercut portion is present along 5.8 inches of the total perimeter. 
     Having briefly described the present invention, the above and further objects, features and advantages thereof will be recognized by those skilled in the pertinent art from the following detailed description of the invention when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a back view of an iron-type golf club head illustrating angle partitions for an undercut in a rear cavity. 
         FIG. 2  is a heel side view of an iron-type golf club head. 
         FIG. 3  is a rear view of an iron-type golf club head. 
         FIG. 4  is a toe side view of an iron-type golf club head. 
         FIG. 5  is a bottom plan view of an iron-type golf club head. 
         FIG. 6  is a bottom perspective view of an iron-type golf club head. 
         FIG. 7  is rear view of an iron-type golf club head. 
         FIG. 8  is a rear view of an iron-type golf club head. 
         FIG. 9  is a side view of an iron-type golf club head illustrating interior portions. 
         FIG. 10  is a cross-sectional view of along line A-A of  FIG. 9 . 
         FIG. 11  is a rear view of an iron-type golf club head. 
         FIG. 12  is a cross-sectional view of along line A-A of  FIG. 11 . 
         FIG. 13  a rear view of an iron-type golf club head illustrating a 295 degrees undercut portion in a rear cavity. 
         FIG. 14  a rear view of an iron-type golf club head illustrating an alternative means for determining an undercut portion in a rear cavity. 
         FIG. 15  a rear view of an iron-type golf club head illustrating an alternative means for determining an undercut portion in a rear cavity. 
         FIG. 16  a rear view of an iron-type golf club head illustrating an alternative means for determining an undercut portion in a rear cavity. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in  FIGS. 1-16 , an iron-type golf club is generally designated  20 . The golf club head  20  includes a body having a face with a surface and a rear cavity with an undercut portion. The body is preferably composed of a material such as titanium materials, stainless steel, carpenter steel, 1020 steel, amorphous metals and the like. The material of the body preferably has a density between 4 g/cm 3  and 10 g/cm 3 . Such titanium materials include pure titanium and titanium alloys such as 6-4 titanium alloy, 6-22-22 titanium alloy, 4-2 titanium alloy, SP-700 titanium alloy (available from Nippon Steel of Tokyo, Japan), DAT 55G titanium alloy available from Diado Steel of Tokyo, Japan, Ti 10-2-3 Beta-C titanium alloy available from RTI International Metals of Ohio, and the like. The body  21  is preferably manufactured through casting. Alternatively, the body  21  is manufactured through forging, forming, machining, powdered metal forming, metal-injection-molding, electro-chemical milling, and the like. 
     As shown in  FIGS. 1-16 , an iron-type golf club head in accordance with the present invention is generally designated  20 . The club head  20  is a cavity-back iron and includes a body  22  having a heel end  24  and a toe end  26 . The body  22  has a front wall  28  for contacting a golf ball and a hosel  30  for receiving a shaft, not shown. In a preferred embodiment the golf club head  20  is composed of a stainless steel, however, those of ordinary skill in the art will appreciate that the golf club head  20  may also be composed of other materials, such as carbon steel, titanium, titanium alloy, zirconium or zirconium alloy. 
     The front wall  28  of golf club head  20  has a ball-striking surface  40  and a back surface  42 . The ball-striking surface  40  has a plurality of scorelines  44  formed therein. In a preferred embodiment the top of the hosel  30  is lower than the toe end of the front wall  28 , thereby lowering the center of gravity of the club head  20 . 
     The golf club head  20  also has a top portion  46 , a sole portion  48 , a heel portion  50 , a toe portion  52  and a rear surface  54 . The top wall  46  extends rearward from the top end of the front wall  28 , in a direction opposite the ball-striking surface  40 , to the rear surface  54  of the body  22 . The sole portion  48  extends rearward from the bottom end of the front wall  28  to the rear surface  54 . The heel portion  50  extends rearward from the heel end  24  of the front wall  28  to the rear surface  54 , and the toe portion  52  extends rearward from the toe end  26  of the front wall  28  to the rear surface  54 . The rear surface  54 , the top portion  46 , the sole portion  48 , the heel portion  50  and the toe portion  52  define an external rear cavity  56  in the body  22  of the club head  20 . The top portion  46 , the sole portion  48 , the heel portion  50  and the toe portion  52  also provide the club head  20  with perimeter weighting to make the club head more forgiving and provide better performance for the typical golfer. 
     The golf club head  20  preferably includes an undercut recess  68  in communication with the external rear cavity  56 . The undercut recess  68  preferably circumscribes the external rear cavity  56 . Alternatively, the undercut recess  68  may extend along only a portion of the external rear cavity  56 . A medallion, not shown, is preferably disposed in the external rear cavity  56  of the body  22 . 
     As shown in  FIGS. 1-16 , the present invention creates a geometry that is aesthetically pleasing, consistent with the best mass properties and accommodating to the golfers interest in sole shapes that minimize interference between the turf and club head. This is accommodated by combining features of better player clubs and with improving player clubs. The radius of the face to sole transition is designed to be a smaller radius to maximize the extension of the flat face within the ball contact locations. Also the radius design penetrated the turf better than a more blunt face to sole transition. 
     Alternatively, the structure of the iron-type golf club is such as disclosed in Helmstetter, et al., U.S. Pat. No. 5,776,010, which is hereby incorporated by reference in its entirety. 
     Alternatively, the structure of the iron-type golf club is such as disclosed in Schmidt, et al., U.S. Pat. No. 5,749,795, which is hereby incorporated by reference in its entirety. 
     Alternatively, the structure of the iron-type golf club is such as disclosed in Schmidt, et al., U.S. Pat. No. 5,704,849, which is hereby incorporated by reference in its entirety 
     Alternatively, the structure of the iron-type golf club is such as disclosed in Blough et al., U.S. Pat. No. 5,921,869, which is hereby incorporated by reference in its entirety. 
     Alternatively, the structure of the iron-type golf club is such as disclosed in Kosmatka, U.S. Pat. No. 5,971,868, which is hereby incorporated by reference in its entirety. 
     Alternatively, the structure of the iron-type golf club is such as disclosed in Kosmatka, U.S. Pat. No. 6,045,455, which is hereby incorporated by reference in its entirety. 
     Alternatively, the structure of the iron-type golf club is such as disclosed in Kosmatka, U.S. Pat. No. 6,186,905, which is hereby incorporated by reference in its entirety. 
     Alternatively, the structure of the iron-type golf club is such as disclosed in Erickson, et al., U.S. Pat. No. 6,210,290, which is hereby incorporated by reference in its entirety. 
     Alternatively, the structure of the iron-type golf club is such as disclosed in Reyes, et al., U.S. Pat. No. 7,144,336, which is hereby incorporated by reference in its entirety. 
     Alternatively, the structure of the iron-type golf club is such as disclosed in Deshmukh, U.S. Pat. No. 7,112,148, which is hereby incorporated by reference in its entirety. 
     Alternatively, the structure of the iron-type golf club is such as disclosed in Aguinaldo, et al., U.S. Pat. No. 7,083,531, which is hereby incorporated by reference in its entirety. 
     Alternatively, the structure of the iron-type golf club is such as disclosed in Wieland, et al., U.S. Pat. No. 7,338,389, which is hereby incorporated by reference in its entirety. 
     Alternatively, the structure of the iron-type golf club is such as disclosed in Nycum, et al., U.S. Pat. No. 7,338,387, which is hereby incorporated by reference in its entirety. 
     Alternatively, the structure of the iron-type golf club is such as disclosed in Holt, et al., U.S. Pat. No. 7,326,126, which is hereby incorporated by reference in its entirety 
     From the foregoing it is believed that those skilled in the pertinent art will recognize the meritorious advancement of this invention and will readily understand that while the present invention has been described in association with a preferred embodiment thereof, and other embodiments illustrated in the accompanying drawings, numerous changes, modifications and substitutions of equivalents may be made therein without departing from the spirit and scope of this invention which is intended to be unlimited by the foregoing except as may appear in the following appended claims. Therefore, the embodiments of the invention in which an exclusive property or privilege is claimed are defined in the following appended claims.