Abstract:
A hosel fitting for connecting a shaft to one of a plurality of club heads comprises a first portion of a tubular structure configured to be affixed to the end of the shaft and a second portion of the tubular structure configured to be received by a bore in a club head. The second portion of the tubular portion can be configured to extend down into the bore. The hosel fitting can also comprise a fastener receiving portion for receiving a fastener configured to affix the hosel fitting to any one of the plurality of club heads.

Description:
RELATED APPLICATIONS INFORMATION  
       [0001]     This application claims priority as a Continuation under 35 U.S.C. §120 to U.S. application Ser. No. 10/053,797, entitled “Golf Club Woods With Wood Club Head Having A Selectable Center of Gravity and a Selectable Shaft,” filed Jan. 18, 2002, which is incorporated herein by reference as if set forth in full. 
     
    
     BACKGROUND  
       [0002]     1. Field  
         [0003]     This invention relates to wood golf clubs and, more particularly, to such wood golf clubs wherein the vertical center of gravity of the wood club head is selectable.  
         [0004]     2. Background  
         [0005]     The golf clubs that are used to hit the golf ball the greatest distances are the “woods”. The woods originally were made of natural wood but today are made of metals or composite materials. However, they continue to be termed “wood golf clubs” or “woods”, and that terminology is used herein.  
         [0006]     The wood golf clubs have wood club heads with relatively large mass, and loft angles of the faces relative to the soles selected to achieve a long flight distance of the struck golf ball. A golf player typically carries up to five woods, which are distinct from each other in that the loft angle varies from about 7 to about 11 degrees for a driver wood golf club, and about 12 degrees and higher for other wood golf clubs. Of the golf clubs termed “woods”, the drivers, with relatively low loft angles, are designed to hit the golf ball the greatest distances. The golfer selects the required wood golf club from this group of wood golf clubs. A wood golf club, and normally a driver, is used for most long shots from the tee, and may be used on intermediate shots on some longer holes.  
         [0007]     As the game of golf has been studied analytically, it has become clear that the design of the wood golf club plays a part in the ability of the player to hit long, accurately directed shots. For example, the shapes of the wood club heads have been optimized. Large-sized wood club heads have been introduced. Wood club heads have been designed to allow the player to add weight to the wood club head.  
         [0008]     While these approaches yield benefits, the present inventors have observed that most players still cannot obtain wood golf clubs that are optimal for the individual. Players vary according to weight, height, strength, skill and other factors. Wood golf clubs may be purchased with varying shaft lengths, but the wood club heads themselves do not change, except as to the loft angle of the face and the ability to add weight to the wood club head in some designs. These approaches do not provide the required flexibility in selecting the wood club heads that are best suited to the individual player.  
         [0009]     There is a need for an improved approach to the design of wood club heads, which allows the player to obtain wood golf clubs that are optimized for the individual. The present invention fulfills this need, and further provides related advantages.  
       SUMMARY  
       [0010]     A hosel fitting for connecting a shaft to one of a plurality of club heads comprises a first portion of a tubular structure configured to be affixed to the end of the shaft and a second portion of the tubular structure configured to be received by a bore in a club head. The second portion of the tubular portion can be configured to extend down into the bore. The hosel fitting can also comprise a fastener receiving portion for receiving a fastener configured to affix the hosel fitting to any one of the plurality of club heads.  
         [0011]     In one aspect, the bore, hosel fitting, and shaft are always substantially in line. In other words, the purpose of the hosel fitting is not to realign the angel of the shaft the club head, i.e., it is not intended to adjust the lie angel. Rather, the hosel fitting is meant to allow anyone of a plurality of shafts to be interfaced with a club head, so that differnet shaft configurations can be tested without changing any other parameters.  
         [0012]     Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. The scope of the invention is not, however, limited to this preferred embodiment. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1  is a perspective view of a wood golf club according to the invention;  
         [0014]      FIGS. 2-4  are sectional views taken on line  2 - 2  of  FIG. 1 , illustrating a preferred technique for adjusting the center of gravity of the wood club head;  
         [0015]      FIGS. 5-7  are side sectional views, like those of  FIGS. 2-4 , and taken on line  2 - 2  of  FIG. 1 , illustrating a second technique for adjusting the center of gravity of the wood club head;  
         [0016]      FIG. 8  is an enlarged, partially exploded, sectional view of the wood club head, taken on line  8 - 8  of  FIG. 1 ; and  
         [0017]      FIG. 9  is a block diagram of a method of providing a wood golf club for a player.  
     
    
     DETAILED DESCRIPTION  
       [0018]      FIG. 1  depicts a wood golf club  20 . The wood golf club  20  is sometimes termed a “wood” club or a “wood”. The wood golf club  20  includes a wood club head  22  and a generally cylindrical wood club shaft  24  affixed to the wood club head  22 . The wood club shaft  24  may be of any operable material of construction, such as metal (e.g., titanium, aluminum), composite (e.g., graphite/epoxy), or even natural wood; produced by any operable method; of any operable diameter; of any operable length; and of any operable physical properties (e.g., elastic modulus, strength). One of the features of the present invention, as will be discussed subsequently in relation to  FIG. 8 , is that the wood club shaft  24  is readily interchangeable.  
         [0019]      FIG. 2  is a sectional view through the wood club head  22 . In the preferred form, the basic structure of the wood club head  22  preferably includes two pieces, a one-piece wood head body  26  and a one-piece wood head face plate  28  affixed to the wood head body  26  by a weldment  30 , by an adhesive, or by other means for affixing. The wood head body  26  may be described in terms of two regions pertinent to the present discussion, a generally planar sole  32  that rests upon the ground  34 , and a crown  36  that is visible to the eye of the player when the player holds the wood golf club  20  and looks downwardly toward the wood club head  22 . The wood head body  26  is preferably hollow, and the crown  36  is convexly (outwardly) curved relative to the interior of the wood head body  26 . The crown  36  is the convexly, outwardly curved portion of the wood head body  26  that is uppermost in  FIG. 2 . The sole  32  is the lowermost portion of the wood head body  26  in  FIG. 2 , which is flat over most of its area and slightly upwardly curved toward the left hand side of  FIG. 2  (remote from the wood head face plate  28 ). The sole  32  meets and is contiguous with the crown  36  on the left hand side of  FIG. 2 .  
         [0020]     The wood head body  26  may be made of any operable material, but is preferably made of a metal alloy such as a titanium alloy. The wood head body  26  may be made by any operable manufacturing process, but is preferably made by a casting technique such as lost wax casting or die casting. It may also be forged or machined. The wood head face plate  28  is made separately from the wood head body  26 . The wood head face plate  28  is preferably also a metal alloy such as a titanium alloy, but a different alloy composition than used in the wood head body  26 . The wood head face plate  28  is preferably forged. After the wood head body  26  and the wood head face plate  28  are fabricated separately, they are joined by fitting the wood head face plate  28  into a recess formed on the wood head body  26  and then welded, adhesively bonded, or otherwise attached in place by the weldment  30  that extends around the periphery of the wood head face plate  28 .  
         [0021]     The inventors have determined that an important performance characteristic of the wood golf club  20  is a vertical location of a center of gravity  38  of the wood head body  26 . The “vertical location” is a distance D CG  from an external surface  40  of the sole  32  toward the crown  36  measured along a line  42  perpendicular to the planar portion of the sole  32 .  
         [0022]      FIGS. 2-4  illustrate three wood club heads  22  for a set of wood golf clubs  20 . These three wood club heads  22  of  FIGS. 2-4  have substantially the same external shapes and volumes. The three wood club heads  22  also have substantially the same total weights. The shapes, volumes, and weights of the three wood club heads  22  in this set of wood golf clubs  20  are substantially the same in order to allow optimization of the selection of the vertical location of the center of gravity  38 , without simultaneously varying other parameters such as shape, loft angle, and total weight of the wood club head  22 .  
         [0023]     The vertical locating of the center of gravity  38  of the three wood club heads  22 , while maintaining the limitation of substantially constant external shape, volume, and total weight, may be accomplished by any operable approach.  FIGS. 2-4  illustrate a preferred approach, changing the thicknesses of the sole  32  and the crown  36  to redistribute weight and move the center of gravity  38  vertically. The thickness changes and the movement of the center of gravity  38  are quite small and may be difficult to discern in precisely scaled drawings, so in  FIGS. 2-4  the thickness variations and the vertical displacement of the center of gravity  38  are exaggerated. In the wood club head  22  of  FIG. 2 , a thickness t s  of the sole  32  is relatively large, and a thickness t c  of the crown  36  is relatively small, so that the weight of the sole is relatively large and the weight of the crown is relatively small. Consequently, the center of gravity  38  is relatively low (i.e., near to the sole  32 ). (The exact locations where the thickness of the sole and the thickness of the crown are measured is not critical, as long as they are generally in the centers of the respective regions and are consistently positioned from wood club head to wood club head within a set.) The weight of a region such as the crown or the sole generally correlates with its thickness within this set of club heads, so that the thicker the region, the greater its weight. In the wood club head  22  of  FIG. 3 , the thickness t s  of the sole  32  is smaller than that of the wood club head  22  of  FIG. 2 , and the thickness t c  of the crown  36  is greater than that of the wood club head  22  of  FIG. 2 . The result is that the center of gravity  38  of the wood club head  22  of  FIG. 3  is higher (i.e., further from the sole  32 ) than the center of gravity  38  of the wood club head  22  of  FIG. 2 . In the wood club head  22  of  FIG. 4 , the thickness t s  of the sole  32  is smaller than that of the wood club head  22  of  FIG. 3 , and the thickness t c  of the crown  36  is greater than that of the wood club head  22  of  FIG. 3 . The result is that the center of gravity  38  of the wood club head  22  of  FIG. 4  is higher (i.e., further from the sole  32 ) than the center of gravity  38  of the wood club head  22  of  FIG. 3 . The wood club head  22  of  FIG. 2  is termed the “L” (low) center of gravity variation, the wood club head  22  of  FIG. 3  is termed the “M” (medium) center of gravity variation, and the wood club head  22  of  FIG. 4  is termed the “H” (high) center of gravity variation. More variations in the vertical location of the center of gravity  38  may be provided than the three illustrated, but initial testing indicates that three variations are sufficient for most applications. The changes in thickness of the sole  32  and of the crown  36  in each case are selected so that the total weight of the wood club head  22  remains the same. The changes in thickness are accommodated by varying the position of an inner wall  44  of the wood club head  22 , so that the shape of an outer wall  46  remains unchanging.  
         [0024]     The wood head bodies  22  of  FIGS. 2-4  are preferably manufactured by a lost wax casting approach. This technique is known generally for the manufacture of hollow golf club head bodies of other designs, see for example U.S. Pat. No. 5,429,365. Generally, there is an outer casting shell that defines the position, shape, and size of the outer wall  46 , and a casting core that defines the position, shape, and size of the inner wall  44 . In the present case, the outer casting shell used for the three wood club heads  22  of  FIGS. 2-4  is the same, so that the wood head bodies  22  have the same external shape, loft angle, and volume, about 335 cubic centimeters in the preferred approach. The casting cores used to cast the three wood head bodies  26  have a constant volume, so that the total amount of metal (and thence the weight) in each of the wood head bodies  26  is a constant amount, preferably in the range of from about 195 to about 205 grams in the preferred approach wherein the wood head bodies  26  are cast from the titanium alloy titanium-6 weight percent aluminum-4 weight percent vanadium. The casting cores are differently positioned, so as to define the thicknesses of the sole  32  and the crown  36  in the manner discussed previously to produce the three different types of wood club heads  22  of  FIGS. 2-4 .  
         [0025]     Once the outer casting shell and the casting core are positioned, molten metal is poured into the space therebetween and cooled to solidify and to form each of the wood head bodies  22 . Any operable castable material may be used, but a titanium alloy such as titanium-6 weight percent aluminum-4 weight percent vanadium is preferred. After the cast metal has solidified, the outer casting shell and the casting core are removed, leaving the final hollow cast wood club head  22  having a cast microstructure. In alternative fabrication techniques, such as a forged or a machined microstructure, the final wood club head  22  has a corresponding microstructure such as a forged or a machined microstructure, respectively.  
         [0026]     Other operable techniques for changing the vertical location of the center of gravity  38  may be used, and  FIGS. 5-7  illustrate one such alternative approach. The pertinent parts of the prior discussion of the embodiments of  FIGS. 2-4  are incorporated here. In the embodiment of  FIGS. 5-7 , a sole fitting  48  is formed in the sole  32 , and a crown fitting  50  is formed in the crown  36 . These fittings  48  and  50  are externally accessible. A corresponding sole weight insert  52  and a crown weight insert  54  are inserted into the respective sole fitting  48  and crown fitting  50 . In a preferred version of this embodiment, the fittings  48  and  50  are female-threaded fittings, and the weight inserts  52  and  54  are matching male-threaded weights. The weight inserts  52  and  54  may be readily installed, removed, and moved in various combinations. The total weight of the sole weight insert  52  and the crown weight insert  54  is maintained constant, so that the total weight of the wood club heads  22  of  FIGS. 5-7  remains constant.  
         [0027]     The approach of  FIGS. 2-4  has the advantage that the weight change is distributed broadly over the sole and the crown. The approach of  FIGS. 5-7  has the advantage that the weight inserts  52  and  54  may be readily changed. The approach of  FIGS. 5-7  has the additional advantage that the total of the weight inserts  52  and  54  may be readily changed, if desired.  
         [0028]     The wood club heads of  FIGS. 2-4  and  5 - 7  are illustrated as being conventional in configuration, except for the ability to change the vertical location of the center of gravity. Other modifications that have been found or may be found useful in wood club heads, such as changes in external shape or total weight, or material of construction, may be utilized in conjunction with the present approach.  
         [0029]     The approaches of  FIGS. 2-4  and  FIGS. 5-7  are used to change the vertical location of the center of gravity  38 . Another factor that significantly influences the performance of the wood golf club  20  is the nature of the wood club shaft  24 .  FIG. 8  illustrates an embodiment of the present approach that allows various types of wood club shafts  24  to be used with the variations of  FIGS. 2-4  and  FIGS. 5-7 . The preferred wood club head  22  of the present approach has no integral hosel, which is a tubular portion that extends upwardly from the crown  36  of the conventional wood club head. The wood club shaft of the conventional wood club is inserted into the hosel and affixed to the hosel with an adhesive such as an epoxy.  
         [0030]     In the present approach as seen in  FIG. 8 , the wood club head  22  has no hosel, but instead has a bore  60  fabricated into the wood head body  26 . The bore  60  has a base  62  that defines the bottom of the bore  60 . An aperture  64  extends through the base  62 . The bore  60  is sized to receive a hosel fitting  66  affixed to an end  68  of the wood club shaft  24 . (The hosel fitting  66  is not integral with the wood club head  22 .) The bore  60  is oriented in the wood club head  22  so that the wood club shaft  24  has the proper orientation to the wood club head  22  and to the wood head face plate  28 . A fastener, preferably a male-threaded fastener  70  such as the illustrated bolt, extends through the aperture  64  of the base  62  to engage the female-threaded hosel fitting  66 , and thence the wood club shaft  24 , to the respective wood club head  22 , when the hosel fitting  66  is inserted into the bore  60 . The sole  32  is locally recessed at recess  72  so that the head of the fastener  70  does not strike the ground  34  when the wood golf club  20  is swung. With this approach, the wood club shaft  24  may be readily changed so that different shafts may be tested and possibly used with the various wood club heads  22 . Shafts of different lengths, diameters, materials of constructions, elastic properties, and other characteristics may thence be utilized.  
         [0031]     An important application of the present approach is to maximize the performance of the golf player for the wood golf clubs, by providing the optimal wood golf club equipment for the individual player.  FIG. 9  illustrates this approach. A wood golf club of a test configuration is provided, numeral  80 . The performance of the wood golf club test configuration when used by the particular player is analyzed, numeral  82 . The steps  80 ,  82  are repeated, numeral  84 , for a new test configuration, and may be repeated as many times as necessary to determine the optimum performance of the player as a function of the several variables that may be evaluated. Variables that may be included in the evaluation include the wood club head  22  and particularly the vertical location of the center of gravity of the wood club head, as discussed above, the type of drive club shaft  24  that is installed to the wood club head  22 , and the type of golf ball being hit. This procedure would be used for a first set of wood golf clubs with a constant selected loft angle, and then may be used for additional sets of wood golf clubs with a different (but constant within any one set) loft angle. The present procedure is expected to yield the most benefits for the wood golf clubs with the lowest loft angles, termed the “drivers”, but it may be used as well for other wood golf clubs.  
         [0032]     The following performance tables for golfers A, B and C, employees of the assignee, were developed by the procedure of  FIG. 9  during the initial testing of the present approach. Each entry in the tables represents the average of multiple hits of a single commercial brand of golf ball. Performance was evaluated using a standard Launch Monitor device for analyzing golf ball movement. In each case, the golfer used three wood golf clubs  20 . The wood club head  22  in each case was a 335 cubic centimeter, 200 gram, 7.5 degree loft angle club. The variation between the wood golf clubs was a low (L), medium (M), or high (H) vertical position of the center of gravity  38 . The following table gives the approximate thicknesses, measured in inches, of the sole  32  and the crown  36  at the same respective point on each wood club head, and the resulting vertical position of the center of gravity in millimeters.  
                                           Club Ident.   Sole Thickness   Crown Thickness   Center of Gravity                   H   0.040   0.060   32       M   0.050   0.050   30       L   0.060   0.040   28                  
 
         [0033]     In the following performance tables, the table entries are, from left to right, the wood club head identification (L, M, or H), the initial launch speed (Vo) of the ball in miles per hour, the spin rate (SR) of the ball in revolutions per minute, the launch angle (LA) of the ball in degrees, the carry distance (CD) on the fly of the golf ball in yards, and the total distance (TD) of the golf ball on the fly and rolling, in yards.  
                                                             Golfer A                Club Ident   Vo   SR   LA   CD   TD                       H   160.5   2066   8.6   228.7   265.4           M   160.3   2163   9.4   237.9   268.2           L   161.2   2436   9.7   239.0   271.9                      
 
         [0034]    
       
         
               
             
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
               
               
                   
               
               
                 Golfer B 
               
             
          
           
               
                   
                 Club Ident 
                 Vo 
                 SR 
                 LA 
                 CD 
                 TD 
               
               
                   
                   
               
             
          
           
               
                   
                 H 
                 158.9 
                 1992 
                 9.9 
                 229.8 
                 266.2 
               
               
                   
                 M 
                 158.8 
                 2263 
                 10.0 
                 233.7 
                 267.8 
               
               
                   
                 L 
                 159.7 
                 2745 
                 10.2 
                 240.5 
                 271.1 
               
               
                   
                   
               
             
          
         
       
     
         [0035]    
       
         
               
             
               
               
               
               
               
               
               
             
           
               
                   
               
               
                   
               
               
                 Golfer C 
               
             
          
           
               
                   
                 Club Ident 
                 Vo 
                 SR 
                 LA 
                 CD 
                 TD 
               
               
                   
                   
               
               
                   
                 H 
                 161.4 
                 3169 
                 14.8 
                 250.9 
                 276.7 
               
               
                   
                 M 
                 159.5 
                 3400 
                 15.3 
                 247.8 
                 272.2 
               
               
                   
                 L 
                 160.1 
                 3384 
                 16.3 
                 248.7 
                 272.8 
               
               
                   
                   
               
             
          
         
       
     
         [0036]     The results set forth in these tables are not to be interpreted as good or bad, consistent or inconsistent. These results simply reflect the performance of each individual player using various types of wood club combinations and for a single type of golf ball.  
         [0037]     In these data, Golfers A and B each achieves the greatest carry distance and total distance with the low center of gravity wood club head. Golfer C, on the other hand, achieves the greatest carry distance and total distance with the high center of gravity wood club head. Based on this data, the selection of wood club heads for Golfers A and B would be different than for Golfer C. These extremely limited data are presented to illustrate the operation of the present approach. In practice, much more data would be gathered for each player, including the effects of variations in the shape and volume of the wood club head, the weight of the wood club head, the loft angle of the wood club head, the type of wood club shaft, the materials of construction of the wood club shaft and the wood club head, the golf ball played, and even other features available in wood club heads.  
         [0038]     This approach may be used in a custom-fitting procedure to find a single wood golf club that is optimal for that player, taking into account all of the variables discussed above. Once that single wood golf club is identified, then the illustrated version with the removable shaft ( FIG. 8 ) may be used by the player. To make the illustrated embodiment into a permanent wood golf club, the hosel fitting  66  may be fixed in place with a permanent adhesive, and a cap may be fitted over the head of the fastener  70  and fixed in place with the permanent adhesive. In other cases, other variables may be considered: wind conditions, launch angle, heel/toe properties, side spin, accuracy relative to an axis, distance accuracy, face mapping, and the like. Thus, for example, a number of golf clubs may be identified for use by the player, such as a wood golf club driver for use in still air conditions, a wood golf club driver for use in headwinds, a wood golf club driver for use in tailwinds, and the like.  
         [0039]     Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.