Abstract:
A golf club head having a striking plate with regions of varying thickness is disclosed herein. A central region has a first thickness range that is thicker than the thickness range of any of the other regions. The thickness of the regions decreases outward from the center. The striking plate may be used on a fairway wood-type golf club head or a driver-type golf club head. The striking plate is preferably composed of steel or titanium.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS  
       [0001]     The present application is a continuation of U.S. patent application Ser. No. 10/605,291, which was filed on Sep. 19, 2003, which is a continuation of U.S. patent application Ser. No. 10/063,927, which was filed on May 24, 2002, now U.S. Pat. No. 6,623,377, which is a continuation of U.S. patent application Ser. No. 09/606,809, which was filed on Jun. 28, 2000, now U.S. Pat. No. 6,398,666, which is a continuation-in-part of U.S. patent application Ser. No. 09/481,167, which was filed on Jan. 12, 2000, now U.S. Pat. No. 6,368,234, which is a continuation-in-part of U.S. patent application Ser. No. 09/431,982, which was filed on Nov. 1, 1999, now U.S. Pat. No. 6,354,962. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a golf club striking plate. More specifically, the present invention relates to a golf ball striking plate having a variable thickness.  
         [0004]     2. Description of the Related Art  
         [0005]     Present golf clubs have repositioned weight in order to lower the center of gravity for better performance. This repositioning of weight has for the most part attempted to thin the crown and striking plate of the golf club while precisely placing the weight in the sole of the golf club. However, thinning the striking plate too much may lead to failure of the golf club.  
         [0006]     When the striking plate impacts a golf ball during a swing, large impact forces (in excess of 2000 pounds) are produced thereby loading the striking plate. In the relatively thin striking plates of hollow metal woods and cavity-back irons, these forces tend to produce large internal stresses in the striking plate. These internal stresses often cause catastrophic material cracking which leads to failure of the club head.  
         [0007]     Computational and experimental studies on hollow metal woods and cavity-backed irons have demonstrated that such catastrophic material cracking most often occurs at impact points on the striking plate. These impact points require added strength to prevent club head failure.  
         [0008]     In designing golf club heads, the striking plate must be structurally adequate to withstand large repeated forces such as those associated with impacting a golf ball at high speeds. Such structural adequacy may be achieved by increasing the striking plate stiffness so that the stress levels are below the critical stress levels of the material used in the striking plate. Typically, for metal woods, the striking plates are stiffened by uniformly increasing the thickness of the striking plate and/or by adding one or more ribs to the interior surface of the striking plate.  
         [0009]     Uniformly increasing the thickness of the striking plate portion typically requires the addition of large amounts of material to adequately reduce the stress sufficient to prevent impact and/or fatigue cracking. However, the addition of such a large amount of material to a striking plate generally adversely affects the performance of the golf club.  
         [0010]     One of the first patents to disclose variable face thickness was U.S. Pat. No. 5,318,300 to Schmidt et al., for a Metal Wood Golf Club With Variable Faceplate Thickness which was filed on Nov. 2, 1992. Schmidt et al discloses thickening the faceplate to prevent cracking.  
         [0011]     A further disclosure of variable face thickness is disclosed in U.S. Pat. No. 5,830,084 to Kosmatka for a Contoured Golf Club Face which was filed on Oct. 23, 1996. Kosmatka addresses contouring the face to thicken certain regions while thinning other regions depending on the stress load experienced by such regions. Kosmatka also discloses a method for designing a face plate according to measured stress levels experienced during impact with a golf ball. Kosmatka, U.S. Pat. No. 5,971,868 for a Contoured Back Surface Of Golf Club Face, filed on Nov. 18, 1997, discloses similar contouring for an iron.  
         [0012]     A more recent disclosure is Noble et al., U.S. Pat. No. 5,954,596, for a Golf Club Head With Reinforced Front Wall, which was filed on Dec. 4, 1997. Noble et al. discloses a face plate with the thickness portion at the geometric center, and gradually decreasing toward the top and bottom, and the sole and heel. The top and bottom ends along a line through geometric center have the same thickness, and the heel and sole ends along a line through geometric center have the same thickness.  
         [0013]     Other references make partial disclosure of varying face thickness. One example is FIG. 8 of U.S. Pat. No. 5,505,453, which illustrates an interior surface of a face with a bulging center and decreasing thickness towards the heel and sole ends, similar to Noble et al. Another example is FIGS. 4C and 4D of U.S. Pat. No. 5,346,216, which discloses a bulging center that decreases in thickness toward the heel and sole ends, and the top and bottom end of the face, similar to Noble et al. However, the prior art has failed to design a striking plate or face plate that varies the thickness according to predicted golf ball impact points on the striking plate.  
       BRIEF SUMMARY OF THE INVENTION  
       [0014]     The present invention is directed at a striking plate for a golf club head that is contoured according to the probability of impact with a golf ball in order to lessen the overall thickness of the striking plate, and thus lessen the weight of the golf club head. Further, the striking plate has regions of varying thickness that allow for more compliance during impact with a golf ball.  
         [0015]     One aspect of the present invention is a golf club head having a body with a crown, a sole, a heel end, a toe end and a striking plate. The striking plate includes a central region, a transition region and a first peripheral region. The central region has a first thickness and occupies 5% to 1 5% of the exterior surface of a core face area. The transition region encompasses the central region and occupies 35 to 50% of the exterior surface of a core face area. The first peripheral region encompasses the transition region and occupies 40% to 55% of the exterior surface of the core face area. The first peripheral region has a thickness less than the first thickness. The transition region has a thickness that transitions from the first thickness to the second thickness.  
         [0016]     Another aspect of the present invention is a striking plate for a golf club head. The striking plate includes a central region, a transition region, a first peripheral region and a second peripheral region. The central region has a first thickness in the range of 0.090 inch to 0.145 inch and occupies 5% to 15% of the exterior surface of a core face area. The transition region encompasses the central region and occupies 35 to 50% of the exterior surface of a core face area. The first peripheral region encompasses the transition region and occupies 40% to 55% of the exterior surface of the core face area. The first peripheral region has a second thickness less than the first thickness and is in the range of 0.050 inch to 0.105 inch. The transition region has a thickness that transitions from the first thickness to the second thickness. The second peripheral region encompasses the first peripheral region and has a third thickness that is in the range of 0.010 inch to 0.085 inch.  
         [0017]     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  
       [0018]      FIG. 1  is a front plan view of a golf club head with the striking plate of the present invention.  
         [0019]      FIG. 2  is a front plan view of the striking plate of  FIG. 1  showing the variable face thickness.  
         [0020]      FIG. 2A  is a front plan view of the golf club head of  FIG. 1  with the variable face thickness pattern superimposed thereon.  
         [0021]      FIG. 3  is a toe side view of the golf club head of  FIG. 1 .  
         [0022]      FIG. 4  is a bottom plan view of the golf club head of  FIG. 1 .  
         [0023]      FIG. 5  is a top plan view of the golf club head of  FIG. 1 .  
         [0024]      FIG. 6  is a heel side view of the golf club head of  FIG. 1 .  
         [0025]      FIG. 7  is a front plan view of a fairway wood golf club head of the present invention with the variable thickness superimposed thereon.  
         [0026]      FIG. 8  is a cross-sectional view along lines  8 - 8  of  FIG. 5 .  
         [0027]      FIG. 9  is a cross-sectional view along lines  9 - 9  of  FIG. 2A .  
         [0028]      FIG. 10  is a cross-sectional view along lines  10 - 10  of  FIG. 2A .  
         [0029]      FIG. 11  is a cross-sectional view along lines  11 - 11  of  FIG. 2A .  
         [0030]      FIG. 12  is a cross-sectional view along lines  12 - 12  of  FIG. 2A .  
         [0031]      FIG. 13  is a cross-sectional view along lines  13 - 13  of  FIG. 2A .  
         [0032]      FIG. 14  is a cross-sectional view along lines  14 - 14  of  FIG. 2A .  
         [0033]      FIG. 15  is a cross-sectional view along lines  15 - 15  of  FIG. 2A .  
         [0034]      FIG. 16  is a cross-sectional view along lines  16 - 16  of  FIG. 2A .  
         [0035]      FIG. 17  is an illustration of impact probabilities for high handicap golfers.  
         [0036]      FIG. 18  is an illustration of impact probabilities for low handicap golfers. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0037]     As shown in  FIGS. 1-8 , a golf club head is generally designated  20 . The golf club head  20  has a body  22  with a crown  24 , a sole  26 , a ribbon  28  and a striking plate  30 . The striking plate  30  generally extends from a heel end  32  to a toe end  34  of the front of the golf club head  20 . The body  22  preferably has an internal hosel  36  for receiving the tip end of a shaft, not shown, through an aperture  38 . The golf club head has a body  22  that is preferably composed of a metal material such as titanium, titanium alloy, stainless steel, or the like, and is most preferably composed of a forged titanium material. The body  22  preferably has a large volume, most preferably greater than 300 cubic centimeters, and is most preferably 350 cubic centimeters. The body  22  preferably weighs no more than 215 grams, and most preferably weighs between 180 and 205 grams. The body  22  has a hollow interior  23 .  
         [0038]     The striking plate  30  is partitioned into a plurality of regions  40 ,  42 ,  44  and  46 , defined by lines  41 ,  43 ,  45  and  47 , each having a different thickness or different thickness range. The exterior surface  53  of the striking plate is substantially smooth for impact with a golf ball, while the interior surface  55  of the striking plate varies in thickness creating a non-planar surface that is contoured according to impact probabilities as described in further detail below. The striking plate  30  is unitary in construction, and may or may not be composed of the same material of the body  22 . The term unitary when used in conjunction with the striking plate  30  means that the striking plate  30  is a single piece and does not have additions to the interior surface  55  such as ribs or weighting members. A central region  40 , defined by dashed line  41 , has a base thickness that is preferably the greatest thickness of the regions  40 ,  42 ,  44  and  46 . The base thickness ranges from 0.200 inch to 0.060 inch, preferably from 0.150 inch to 0.075 inch, and is most preferably within the range of 0.145 inch to 0.090 inch. A transition region  42  has a thickness that ranges between the thickness of the central region  40  and a first peripheral region  44 , preferably ranges from 0.150 inch to 0.090 inch, and most preferably ranges from 0.140 inch to 0.080 inch. The first peripheral region  44  has a thickness that ranges from 0.110 inch to 0.040 inch, preferably ranges from 0.105 inch to 0.050 inch, and most preferably ranges from 0.100 inch to 0.075 inch. A second peripheral region  46  preferably is the thinnest region of the striking plate regions  40 ,  42 ,  44  and  46 . The second peripheral region  46  has a thickness that ranges from 0.085 inch to 0.010 inch, preferably ranges from 0.080 inch to 0.045 inch, and most preferably ranges from 0.075 inch to 0.050 inch.  
         [0039]     In a preferred embodiment, as shown in  FIG. 2 , the central region has a thickness range of 0.145 inch to 0.090 inch, the transition region  42  has a thickness range of 0.140 inch to 0.080 inch, the first peripheral region  44  has a thickness range of 0.105 inch to 0.090 inch, and the second peripheral region  46  has a thickness range of 0.075 inch to 0.050 inch.  
         [0040]     Preferably, as shown in  FIG. 2 , the central region  40  is 5% to 15% of the surface area of the core face  49  of the striking plate  30 . The core face  49  is defined as the central region  40 , the transition region  42  and the first peripheral region  44 . The core face area of the striking plate  30  has an area between 4.80 square inches and 5.50 square inches, preferably between 5.10 square inches and 5.40 square inches, and most preferably 5.38 square inches. The transition region  42  is preferably 35% to 50% of the surface area of the core face  49 , and the first peripheral region  44  is preferably 40% to 55% of the surface area of the core face  49 . In a preferred embodiment, the central region is 8.8% of the surface area of the core face  49 , the transition region is 42.2% of the surface area of the core face  49 , and the first peripheral region  44  is 50% of the surface area of the core face  49 .  
         [0041]      FIG. 7  illustrates an alternative embodiment of the present invention for a fairway wood golf club head  20 . In this embodiment, the central region has a thickness range of 0.135 inch to 0.125 inch, the transition region  42  has a thickness range of 0.130 inch to 0.090 inch, the first peripheral region  44  has a thickness range of 0.095 inch to 0.085 inch, and the second peripheral region  46  has a thickness range of 0.075 inch to 0.045 inch.  
         [0042]     Table One sets forth the thickness ranges of the central region  40 , the first peripheral region  44  and the second peripheral region  46  for preferred embodiments for drivers (lofts  7  degrees through 12 degrees) and fairway woods (2 wood through 9 wood).  
                                 TABLE ONE                           Striking Plate Thickness                Second Peripheral   First Peripheral           Club   Region   Region   Center Region               07° Driver   .050 ± .005   .100 ± .005   .140 ± .005       08° Driver   .050 ± .005   .100 ± .005   .140 ± .005       09° Driver   .050 ± .005   .100 ± .005   .140 ± .005       10° Driver   .050 ± .005   .100 ± .005   .140 ± .005       11° Driver   .050 ± .005   .100 ± .005   .140 ± .005       12° Driver   .050 ± .005   .100 ± .005   .140 ± .005       2 Wood   .050 ± .005   .100 ± .005   .140 ± .005       3 Wood   .055 ± .005   .090 ± .005   .130 ± .005       Strong 3   .060.005   .090 ± .005   .130 ± .005       4 Wood   .060 ± .005   .085 ± .005   .125 ± .005       Strong 4   .065 ± .005   .090 ± .005   .130 ± .005       5 Wood   .065 ± .005   .085 ± .005   .125 ± .005       7 Wood   .070 ± .005   .085 ± .005   .125 ± .005       9 Wood   .075 ± .005   .085 ± .005   .125 ± .005                  
 
         [0043]     Cross-sections of the striking plate  30 , taken from  FIG. 2A , are illustrated in  FIGS. 9-16 .  FIG. 9  illustrates a vertical cross-section of the mid-section of the striking plate  30  with the central region  40 , the transition region  42 , the first peripheral region  44  and the second peripheral region  46  on the contoured interior surface  55  as opposed to the relatively smooth, albeit scorelines, of the exterior surface  55  of the striking plate  30 .  FIGS. 10 and 11  illustrate vertical cross-sections that are adjacent both sides of the mid-section, and which only includes the transition region  42 , the first peripheral region  44  and the second peripheral region  46 .  FIG. 12  illustrates a vertical cross-section on the heel end  32  of the striking plate  30  that has a wall of the internal hosel  36  integrated therewith in a preferred embodiment.  FIG. 12  otherwise shows the first peripheral region  44  and the second peripheral region  46 . Although the wall of the internal hosel  36  is shown as integrated with the striking plate  30 , alternative embodiments have the internal hosel off-set from the interior surface  55  of the striking plate  30 .  FIG. 13  illustrates a vertical cross-section of the toe end  34  of the striking plate  30 , which only includes the first peripheral region  44  and the second peripheral region  46 .  
         [0044]      FIG. 14  illustrates a horizontal cross-section of the horizontal mid-section of the striking plate  30 , which shows the central region  40 , the transition region  42 , the first peripheral region  44 , the second peripheral region  46 , and the wall of the internal hosel  36 .  FIG. 15  illustrates a horizontal cross-section below the horizontal mid-section of the striking plate  30 , which only includes the transition region  42 , the first peripheral region  44 , the second peripheral region  46 , and the wall of the internal hosel  36 .  FIG. 16  illustrates a horizontal cross-section further below the horizontal mid-section of the striking plate  30 , which only includes the first peripheral region  44 , the second peripheral region  46 , and the wall of the internal hosel  36 .  
         [0045]     The striking plate  30  will also have a plurality of scorelines  75  thereon which will effect the thickness of each of the regions  40 ,  42 ,  44  and  46  at each particular scoreline. A more detailed explanation of the scorelines  75  is set forth in U.S. Pat. No. 6,443,856, entitled Contoured Scorelines For The Face Of A Golf Club, and incorporated by reference in its entirety.  
         [0046]     As shown in  FIG. 2 , the striking plate  30  has a geometric center  80 . The geometric center  80  is found by plotting the geometric center of the entire area of the striking plate  30 . The central region  40  has a geometric center  82  that is offset from the geometric center  80  of the striking plate  30 . Additionally, the thickest portion of the central region  40  is preferably at a point  84 , offset from both the geometric center  80  of the striking plate and the geometric center  82  of the central region  40 .  
         [0047]     As mentioned previously, the thickness of the regions  40 ,  42 ,  44  and  46 , and for the most part, the thickness of the striking plate  30 , corresponds to impact probability.  FIGS. 17 and 18  illustrate the impact points during a golf swing for high handicap players and low handicap players, respectively. As shown in  FIG. 17 , the high handicap players had impacts  90  within an elliptical area  100  that extended through the center of the striking plate  30 . In comparison, low handicap players had impacts  90  that were more concentrated and within a circular area  1   02  of the striking plate  30 . These impacts  90  illustrate the points on a striking plate  30  that have the highest probability of undergoing the greatest stress during impact with a golf ball. Therefore, these points require greater thickness than other areas of the striking plate  30 . Thus, the regions  40 ,  42 ,  44  and  46  correlate to this impact probability in order to design a striking plate with greater thickness where it is needed instead of in areas low impact probability. The present invention may be described as being thinner at the heel and toe ends  32  and  34  than the central region  40 .  
         [0048]     The variation in the thickness of the striking plate  30  also allows for the greatest thickness of regions  40 ,  42 ,  44  and  46  to be distributed in the center region  40  of the striking plate  30  thereby enhancing the flexibility of the striking plate  30  which corresponds to greater compliance of the striking plate  30  during impact with a golf ball thereby providing for reduced energy loss with allows for greater distance.  
         [0049]     The striking plate  30  is preferably composed of a stainless steel. Alternatively, the striking plate  30  is composed of a titanium or titanium-alloy material. In yet an alternative embodiment, the striking plate  30  is composed of a vitreous metal such as iron-boron, nickel-copper, nickel-zirconium, nickel-phosphorous, and the like. Yet in further alternative embodiments, the striking plate  30  is composed of ceramics, composites or other metals.  
         [0050]     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.