Abstract:
A golf club iron having a head center of gravity that is low and forward enough to provide a better swing, good striking and swinging feel, and improved ball flight is disclosed. The iron has a recess in a leading edge region and a high density insert disposed within the recess to achieve the desired center of gravity location.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation of U.S. patent application Ser. No. 13/472,228, filed on May 15, 2012, which claims priority to U.S. Provisional Patent Application No. 61/490,365, filed on May 26, 2011, the disclosure of which is hereby incorporated by reference in its entirety herein. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    The present invention relates to a golf club iron having a high density leading edge. 
         [0005]    2. Description of the Related Art 
         [0006]    Technical innovation in the size, structure, configuration, material, construction, and performance of golf clubs has resulted in a variety of new products. Most irons are constructed in such a way that the head is made from a single type of parent material, such as steel. Some irons have discrete weighting elements incorporated into their structure, but these weights typically are incorporated into sole or perimeter regions located away from the face. As such, most irons currently available on the market do not have a center of gravity (CG) that is located low or forward enough in the head for the head to achieve optimum performance. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    One aspect of the present invention is a golf club iron having a head center of gravity that is low and forward enough to provide the iron with a better swing, good striking and swinging feel, and improved ball flight. 
         [0008]    Another aspect of the present invention is a golf club comprising a head comprising a face, a sole, a toe, a heel, and a recess, and an insert sized to fit within the recess, wherein the head is composed of a first material having a first density and the insert is composed of a second material having a second density, wherein the second density is greater than the first density, wherein the face has a lower portion adjacent the sole, and wherein the recess is located in at least part of the lower portion of the face and extends into at least part of the sole. The head may be selected from an iron-type golf club head, a wedge-type golf club head, and a hybrid-type golf club head. 
         [0009]    In some embodiments, the insert may be secured within the recess via welding, press fit, mechanical entrapment, bonding, or fastening. The second density may be no less than 8 g/cm 3  and no more than 20 g/cm 3 , and the first material may be steel and the second material may be a tungsten alloy. The recess may have a convex bottom portion and the insert may have a concave back portion that mates with the convex bottom portion. Alternatively, the recess may have a flat bottom portion and the insert may have a flat back portion that mates with the flat bottom portion. The recess may extend from a furthest extent of the toe to a furthest extent of the heel, or the recess may extend only part way from the toe to the heel. The face may be integrally formed with the sole. In some embodiments, the head may be cast from stainless steel, and in other embodiments, the head may be forged from a metal alloy. 
         [0010]    Another aspect of the present invention is an iron-type golf club head comprising a face, a sole, a heel region, a toe region, and a leading edge region, wherein the face has a lower portion proximate the sole, wherein the leading edge region extends from the lower portion into the sole, wherein the leading edge region comprises a first material having a first density, wherein a remainder of the face and the sole comprises a second material having a second density, and wherein the leading edge region extends from the heel region to the toe region. The first density may be no less than 8 g/cm 3  and no more than 20 g/cm 3 , and the first material may be a tungsten alloy and the second material may be steel, which may be selected from the group consisting of carbon steel and stainless steel. 
         [0011]    Yet another aspect of the present invention is an iron-type golf club head comprising a face, a sole, a hosel, and a leading edge region, wherein the face has a lower portion proximate the sole, wherein the leading edge region extends from the lower portion into the sole, wherein the leading edge region comprises a high-density metal alloy, and wherein the face, sole, and hosel are each composed of a steel material. The high-density metal alloy may have a density of no less than 8 g/cm 3  and no more than 20 g/cm 3 , and may be a tungsten alloy. In some embodiments, the steel material may be carbon steel. 
         [0012]    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 
         [0013]      FIG. 1  is a front, plan view of a first embodiment of the present invention. 
           [0014]      FIG. 2  cross-sectional view along lines  2 - 2  of the embodiment shown in  FIG. 1 . 
           [0015]      FIG. 3  is a cross-sectional view of a second embodiment of the present invention. 
           [0016]      FIG. 4  is a cross-sectional view of a third embodiment of the present invention. 
           [0017]      FIG. 5  is a graph showing the center of gravity locations in various iron club heads. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    The golf club head of the present invention includes a material, located in or around the bottom portion of the face where it meets the sole, having a higher density than that of the material used to form the remainder of the club head. This high density material is attached to the club head via welding, press fit, mechanical entrapment, bonding, fastening, or the like. 
         [0019]    A preferred embodiment of the present invention is shown in  FIGS. 1 and 2 . The iron-type golf club head  10  of the present invention has a face  20 , a sole  30  extending rearwardly from a lower portion  22  of the face  20 , and a recess  40  located in region  45  spanning at least part of the lower portion  22  of the face  20  and extending into at least part of the sole  30 . This region  45  is commonly known as the leading edge or the “chin” of the golf club iron head. An insert  50  is affixed to the head  10  within the recess  40  via welding, press fit, mechanical entrapment, bonding, fastening, or the like. As shown in  FIG. 2 , the recess  40  has a convex bottom portion  42  and the insert  50  has a concave back portion  52  that mates with the convex bottom portion  42  and provides additional surface area for welding, bonding, and/or fastening procedures. 
         [0020]    Another embodiment of the present invention is shown in  FIG. 3 . In this embodiment, the recess  40  has a longer, convex bottom portion  42  and the insert  50  has a longer concave back portion  52  for mating with the convex bottom portion  42 . A third embodiment, shown in  FIG. 4 , has a recess  40  without a convex bottom portion. Instead, the recess  40  has a flat bottom surface  44 , and the insert  50  has a flat mating back surface  54  that lines up with and can be affixed to the flat surface  44  of the recess  40 . 
         [0021]    The insert  50  of the present invention is composed of a material having a density higher than that of the material of the club head  10 . The density of the material used to make the insert  50  may range from 7 g/cm 3  to 20 g/cm 3 , and preferably is 18 g/cm 3 . The head  10  preferably is made of a type of steel material, such as carbon or stainless steel, and the insert  50  preferably is made of a tungsten alloy. 
         [0022]    The recess  40  may take up the entire chin or leading edge region  45  of the golf club head  10 , extending all the way from the toe  12  of the golf club head to the heel  14 , or, as shown in  FIG. 1 , the recess  40  may extend only part of the way between the toe  12  and the heel  14 . The greater the recess  40  size is, the greater the size of the high density insert  50 , so a golfer desiring a iron having an extremely heavy chin weight would select a iron head with a recess  40 , and thus an insert  50 , extending from the furthest reaches of the toe  12  to the furthest reaches of the heel  14  within the chin region  45 . 
         [0023]    The irons of the present invention have high density leading edges and thus extremely low, forward centers of gravity and moderate loft/de-loft moments of inertia (Iyy). The graph  100  in  FIG. 5  shows the center of gravity locations, mapped according to height and depth of the iron head frames, of 6-irons of the present invention and 6-irons currently available on the market. The circled region  110  in the graph indicates the center of gravity locations of irons designed according to the present invention, while the small circles represent Callaway irons and the small dashes represent non-Callaway irons. Center of gravity locations are generally obtainable by referring to the leading edge weights of the irons. 
         [0024]    The irons of the present invention may be composed of any number of materials known in the art, including metal alloys and composites. The irons of the present invention may also take any shape or general structure known in the art, including, but not limited to, the shapes and structures disclosed in U.S. Pat. Nos. 5,626,530, 5,749,795, 6,769,998, 7,083,531, 7,338,387, 7,338,389, and 8,043,165, the disclosure of each of which is hereby incorporated by reference in its entirety herein. 
         [0025]    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.