Abstract:
The invention provides a golf club head having adjustable weight, allowing the golfer to fine tune the club for his or her swing. The club head includes a body having a ball-striking face, a sole, a crown, and a side extending rearwardly from the face. The body defines an interior cavity and a recess on a selected wall of the body spaced apart from the striking face. A threaded opening is disposed in the recess. The club head further includes a weight assembly having fastener and a mass element configured to be press-fit into the recess the such that a first end is adjacent the bottom of the recess. The mass element also has an aperture configured to receive the fastener flush. The fastener removably attaches the weighting assembly to the selected wall of the club head. Pressure from the fastener attachment provides a press-fit of the mass element in the tapered recess of the selected wall.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This is a divisional of prior application Ser. No. 10/913,001, filed Aug. 6, 2004, which is a continuation of prior application Ser. No. 10/290,817, filed Nov. 8, 2002, now U.S. Pat. No. 6,773,360, which is herein incorporated by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The invention relates generally to a golf club head and, more particularly, to a wood-type golf club head having a volume of at least 150 cc.  
       BACKGROUND OF THE INVENTION  
       [0003]     Current driver and fairway wood golf club heads are typically formed of steel or titanium alloys. For example, oversize driver heads exceeding 300 cc in volume are usually formed of a lightweight titanium alloy such as Ti 6A1-4V. Unless modified, oversize heads can have a relatively high center of gravity, which can adversely affect launch angle and flight trajectory of a struck golf ball. Thus, many club heads have integral sole weight pads cast into the head at a predetermined location to lower the center of gravity of the club head. Also, epoxy may be later added to the club head through the hosel to obtain a final desired weight of the club head. Alternatively, club heads may have weights, usually of a higher density material than the titanium or steel alloy, externally attached to the sole. The weights may be welded in place or attached using a fastener such as a screw. Because of the repeated contact with the ground during the golfer&#39;s swings, use of an adhesive alone is not advised as a long term, external attachment method for a weight.  
         [0004]     These weights are of a prescribed amount and are usually permanently attached to the club head prior to purchase. However, the club&#39;s weighting typically is set for a standard, or ideal, swing type. Thus, even though the weight may be too light or too heavy, or too far forward or too far rearward, a golfer with a less than ideal swing type cannot adjust or customize the club weighting to accommodate his or her particular needs.  
         [0005]     It should, therefore, be appreciated that there is a need for a golf club head that allows a golfer to fine tune the weight of the club head for his or her swing. The present invention fulfills this need and others.  
       SUMMARY OF THE INVENTION  
       [0006]     The invention provides a golf club head having adjustable weight, allowing the golfer to fine tune the club for his or her swing. The club head includes a body having a ball-striking face, a sole, a crown, and a side extending rearwardly from the face. The body defines an interior cavity and a recess on a selected wall of the body spaced apart from the striking face. A threaded opening is disposed in the recess. The club head further includes a weight assembly having a fastener and a mass element configured to be press-fit into the recess the such that a first end is adjacent the bottom of the recess. The mass element also has an aperture configured to receive the fastener flush. The fastener removably attaches the weighting assembly to the bottom wall of the club head. Pressure from the fastener attachment provides a press-fit of the mass element in the recess. Thus, a golfer can try out a selected first weight on the club head and then change to a different second weight that may be more desirable in its mass and/or mass distribution properties.  
         [0007]     In a preferred embodiment, the weight assembly further includes a retaining element configured to retain the fastener the aperture in the mass element and to receive the tip of a tool for tightening or loosening the fastener. The retaining element also serves to aid in removing the mass element when the fastener is loosened, as the head of the fastener presses against the retaining element in an outward direction while the retaining element is secured to the mass element. Preferably there is a low friction element positioned between the head of the fastener and the retaining element. The mass and retaining elements move in concert as the fastener is loosened from the selected wall.  
         [0008]     In a detailed aspect of a preferred embodiment, the mass element may be configured in various shapes and densities. For example, the weight assembly can have a triangular shape and one side portion could be different in density. Thus, the weight assembly could move the center of gravity slightly forward, slightly to the toe and rear or slightly to the rear and heel, depending upon the arrangement of the heavier side portion. Other shapes of the weight assembly can be employed for different weighting schemes as well as for cosmetic effect.  
         [0009]     In another detailed aspect of a preferred embodiment, the body defines a plurality of recesses for receiving a weight assembly. Optionally, a combination of a weight assemblies and plugs can be secured in the plurality of recesses.  
         [0010]     For purposes of summarizing the invention and the advantages achieved over the prior art, certain advantages of the invention have been described herein above. Of course, it is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.  
         [0011]     All of these embodiments are intended to be within the scope of the invention herein disclosed. These and other embodiments of the present invention will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiments having reference to the attached figures, the invention not being limited to any particular preferred embodiment(s) disclosed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     Embodiments of the present invention will now be described, by way of example only, with reference to the following drawings in which:  
         [0013]      FIG. 1  is a cross-sectional view of a first preferred embodiment of a club head in accordance with the invention, showing a plug and a removable weight attached to the sole of the club head.  
         [0014]      FIG. 2A  is a cross-sectional view of a mass element for the club head of  FIG. 1 .  
         [0015]      FIG. 2B  is a cross-sectional view of a screw to be received through the mass element of  FIG. 2A .  
         [0016]      FIG. 2C  is a cross-sectional view of a retaining element for the club head of  FIG. 1 .  
         [0017]      FIG. 2D  is a cross-sectional view of an alternative retaining element for the club head of  FIG. 1 .  
         [0018]      FIG. 3A  is a plan view of the exposed end of the mass element of  FIG. 2A .  
         [0019]      FIG. 3B  is a top plan view of the screw of  FIG. 2B .  
         [0020]      FIG. 3C  is a plan view of the exposed end of the retaining element of  FIG. 2C .  
         [0021]      FIG. 4  is a partial cross-sectional view of a second preferred embodiment of a club head in accordance with the invention, depicting a single attachment to the sole of the club head.  
         [0022]      FIG. 5A  is a plan view of the exposed end of an alternative mass element similar to  FIG. 3A , depicting two different density regions within the mass element.  
         [0023]      FIG. 5B  is a plan view of the exposed end of another mass element, having a triangular shape and having a density that is different along one side from the remaining two sides.  
         [0024]      FIG. 5C  is a plan view of the exposed end of yet another mass element similar to  FIG. 5B  and having a different density in one of the three corners.  
         [0025]      FIG. 6  is a sectional view of a third preferred embodiment of the present invention.  
         [0026]      FIG. 7  is a partial sectional view of a fourth preferred embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]     Now with reference to the illustrative drawing, and particularly  FIG. 1 , there is shown a club head  10  having a main body  16  and removable weight assembly  100  secured in one of a plurality of recesses  32 . The weight assembly  100  includes a mass element  102 , a screw  104  and a retaining element  110 . The recesses  32  can interchangeably receive a weight assembly  100  or a plug  14 . The plug  14  is preferably formed of a material having similar density of the main body  16 . By having more than one recess  32 , a golfer can fine tune the weighting of the club head  10  by locating weight assemblies  100  forward toward a front wall  20  or rearward away from the front wall  20 .  
         [0028]     The main body  16  is formed of metal and a striking face  22  may be integrally formed or attached to the main body  16  using methods known to those skilled in the art. A sole  18  may be integrally formed with the main body  16  or separately formed then attached to the main body  16  ( FIG. 4 ). The recess  32  is defined by a recess wall  30  and a recess bottom  38 . The recess bottom  38  defines a threaded opening  12  for attachment of the weight assembly  100 . As shown in  FIGS. 1 and 4 , the recess wall  30  may be tapered and the threaded opening  12  may be further defined by a boss  35  extending either inward ( FIG. 1 ) or outward ( FIG. 4 ) relative to the recess  32 . In this embodiment, the boss  35  has a length at least half the length of the body of the screw  104  and, more preferably, the boss  35  has a length at least 1.5 times a diameter of the body of the screw  104 . Alternatively, as shown in  FIG. 6 , the threaded opening  12  may be formed without a boss  35 .  
         [0029]     With continued reference to  FIG. 1 , the recess  32  is defined on the sole  18  and the mass element  102  is secured in place using the screw  104 . Another user removable fastener such as a bolt may alternatively be used. The pressure from the engagement of the screw  104  provides a press-fit of the mass element  102  into the recess  32  on the sole  18 , as sides  106  of the mass element  102  slide tightly against the recess side wall  30 . A bottom end surface  108  of the mass element  102  preferably contacts the recess bottom  38 ; however, retention of the weight assembly  100  derives substantially from the press-fit between the sides  106  of the mass element  102  and the recess side wall  30 . The retaining element  110  allows for easy removal of the mass element  102 . This feature allows the club head  10  to be modified by a golfer who seeks to configure the club head  10  with more than one weight assembly  100  at the one or more recesses  32  on the sole  18 . Upon determination of the final desired weighting of the sole  18 , the weight assembly  100  is left securely attached to the club head  10  for play. The recesses  32  may also be located more toward a toe or a heel of the club head  10 , as desired. In alternative embodiments, the one or more recesses  32  may be provided on a top wall  21  or side wall  23  of the main body  16  to allow weighting at that portion of the club head  10 .  
         [0030]     Referring to  FIGS. 2A and 3A , the mass element  102  has a hexagonal shape and defines an aperture  112  sized to freely receive the screw  104 . As shown in  FIG. 2A , the aperture  112  has a first diameter at a first end  114  that is smaller than a second diameter at a recess  115  in a second end  116 . The first diameter is sized to freely receive a body  118  ( FIG. 2B ) of the screw  104  and the second diameter is sized to receive the retaining element  110 . The second end  116  of the mass element  102  having the second diameter has internal threads  117  for securing the retaining element  110  over a head  120  of the screw  104  (see  FIG. 3B ).  
         [0031]      FIGS. 2C and 3C  show the retaining element  110  having an outer diameter (Φ) and an outer surface  122  that includes threads to mate with the internal threads  117  of the mass element  102 . Preferably, the retaining element  110  has an aperture  124  that has a first diameter at an inner end  126  that is greater than a second diameter at an outer end  128 . The first diameter is sized to freely receive the head  120  of the screw  104 . More preferably, a low-friction element  121  having low-friction surfaces is sized to be received in the retaining element aperture  124  at the inner end  126 . The low-friction element  121  has an aperture  123  having substantially the same diameter as the second diameter at the outer end  128  of the retaining element aperture  124 .  
         [0032]     With reference now to  FIG. 2D , an alternative retaining element  110 ′ may be provided having an aperture  124 ′ with a single diameter. The low-friction element  121  may then have an outer diameter corresponding to the outer diameter of the retaining element  110 ′. The apertures of the low-friction element  121  and the retaining element  110 ′ are both sized to receive a tip end of a screwdriver (not shown) for tightening and/or loosening the screw. When assembled, the screw head  120  is between the mass element  102  and retaining element  110 ′. For other types of fasteners, the apertures of the low-friction element  121  and the retaining element  110 ′ are preferably sized to receive the appropriate fastening tool. Also, instead of a separate low-friction element  121 , appropriate surfaces of the retaining element  110 ′ adjacent to the screw head  120  may be treated to obtain similar low friction characteristics so that outward rotation of the screw  104  does not cause rotation of the retaining element  110 ′.  
         [0033]     With reference again to  FIG. 1 , the weight assembly  100  comprises a conventional screw  104  and the material of the mass element  102  has a density different from the density of the material of the main body  16 . The retaining element  110  may comprise any material and is preferably a metal. As shown in  FIG. 3A , as well as  FIGS. 5A-5C , the mass element  102  may have any outer shape, such as triangular, oval or rectangular. After the desired weight assembly configuration is determined and confirmed to meet the needs of a golfer, adhesive may be applied to the threaded body  118  of the screw  104  to further secure the weight assembly  100  to the club head  10 . Of course, heating or other methods known to those skilled in the art may be used to allow removal of the weight assembly  100  if adhesive has been applied.  
         [0034]     For installation of the weight assembly  100  of  FIG. 1 , the screw head  120  is preferably placed into the inner end  126  of the retaining element  110  and then the body  118  of the screw  104  is placed through the aperture  112  of the mass element  102 . The head  120  is trapped between the retaining element  110  and the mass element  102  as the retaining element  110  is screwed into place. The threaded body  118  of the screw  104  is screwed into the threaded opening  12  of the recess  32 . A screwdriver engages the head  120  of the screw  104  through the retaining element aperture  124 , and as the screw  104  engages the threads of the threaded opening  12 , the weight assembly  100  achieves a press-fit against the tapered recess wall  30 . This embodiment also allows easier removal of the weight assembly  100 , if desired, since as the screwdriver turns the bead  120  of the screw  104 , the screw  104  applies an outward force on the retaining element  110  and thus helps to decouple the mass element  102  from the tapered recess wall  30 .  
         [0035]     Advantages of the present invention may be obtained without the use of the retaining element  110 , as illustrated in a preferred embodiment of  FIG. 4 . In this embodiment the weight assembly  100 ′ includes a mass element  102 ′ and a screw  104 . The engagement of the screw  104  into the threaded opening  12  causes the sides  106  of the mass element  102 ′ to be compressed against the tapered recess wall  30 , thereby achieving a secure press-fit.  
         [0036]     With reference now to  FIG. 6 , another preferred embodiment of a club head  10  having a retaining element  110  with a mass element  102 ′ and screw  104  is shown. A recess bottom  138  is configured to have a taper steeper than the recess side wall  30 . The mass element  102 ′ may have a complementary bottom end surface  108 ′ to contact the recess bottom  138 . Alternatively, the mass element  102 ′ may have a substantially planar bottom end surface  108  that is tightly compressed against the tapered recess bottom  138  as the screw  104  is engaged.  
         [0037]     With reference now to  FIGS. 5A-5C , the mass element  102 ,  102 ′ may have at least one axis of symmetry  150  and a higher density region  140  that has a higher density than a lower density region  142  of the mass element  102 ,  102 ′. Thus, the moment of inertia and center of gravity of the club head  10  may be altered by changing the orientation of the mass element  102 ,  102 ′ in the recess  32 . For example, the higher density region  140  may be aligned toward the front, toe, heel and/or rear direction of the club head  10 . Examples of such a mass element  102 ,  102 ′ are a hexagonal-shaped mass element with a higher density region  140  ( FIG. 5A ), a triangular-shaped mass element with a higher density region  140  ( FIG. 5B ), and a triangular-shaped mass element  102 ,  102 ′ with a higher density region  140  ( FIG. 5C ). The different density regions  140 ,  142  of the mass element  102 ,  102 ′ may be achieved by methods known to those skilled in the art, such as using compression and sintering techniques, as in powder metallurgy, to achieve the desired density distribution in a metal product.  
         [0038]     Yet another embodiment of the present invention is shown in the partial sectional view of  FIG. 7 . The recess  232  has substantially straight walls  230  formed toward the interior of the club head  10 , and a boss  235  located in the recess  232 . A recess bottom wall  234  that forms the boss  235  is tapered outwardly. The mass element  202  has substantially straight, parallel walls, and the pressure by the screw  104  is focused on the inner walls of the mass element  202  to press-fit the weight assembly in the recess  232 . It is understood that a retaining element, comprising a low friction surface, may be used with the mass element  202  to form the removable weight assembly.  
         [0039]     Although the invention has been disclosed in detail with reference only to the preferred embodiments, those skilled in the art will appreciate that additional golf club heads can be made without departing from the scope of the invention. Accordingly, the invention is defined only by the claims set forth below.