Abstract:
A golf club head and a method of tuning the golf club head. The golf club head includes a body having a front surface, a back surface, a heel end, a toe end, a sole extending between the lower portions of the heel and the toe ends, a top portion extending between the upper portions of the heel and toe ends, and a cavity. One or more magnets are mounted in the cavity such that their distance into the cavity can be adjusted. A detachable face plate having one or more magnets attached to a back surface of the detachable face plate is slidably mated with guides extending from the body. At least two of the magnets are positioned such that the north pole of the magnet in the cavity faces the north pole of a magnet attached to the back surface of the detachable face plate. A repulsive force between the north poles pushes the detachable face plate away from the body and into a stop coupled to the body. The strength of the repulsive force is adjusted by the distance between the magnets to provide a golfer with the desired face plate stiffness.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates generally to golf equipment and, in particular, to a golf club head. 
   An important factor governing the distance and accuracy of a golfer&#39;s drive is the amount of energy transferred from the golf club head to a golf ball when it impacts the golf ball. Ideally, the point of impact on the face of the golf club head is below the center of gravity of the golf club head and the point of impact on the golf ball is below the center of gravity of the golf ball. In addition, the theoretical plane containing the impact point on the golf club head, the center of gravity of the golf club head, and the center of gravity of the golf ball should be in alignment with the intended travel path of the golf ball. When these conditions are met, the golf club head is properly aligned and produces maximum face response characteristics. 
   To help golfers achieve proper alignment, golf club manufacturers have concentrated a relatively large mass of the golf club head in its sole. This configuration has made it easier for a golfer to place the center of gravity of the golf club head below the center of gravity of the golf ball; however it is still difficult for a golfer to achieve perfect alignment. For example, a golfer may have the club head square immediately prior to impact, but the actual point of impact with the club head may be shifted from the desired point on the club head to either the heel end or the toe end. This results in improper alignment because the club head becomes twisted to an out of square position and results in less than the maximum amount of energy being transferred to the golf ball. The terms twisting, twisted, or gyration are used here to define a rotation of the club head at the time of impact about an axis which passes through the center of gravity of the club head and is parallel to the axis of the golf club shaft. To dampen or reduce the effects caused by twisting of the club head, golf club manufacturers have placed relatively large concentrations of mass in the heel and toe of the club head to increase the moment of inertia and thereby maximize the energy transfer from the club head to the golf ball. Although these techniques have improved the ability of the golfer to increase the consistency with which they properly align the golf club, slight misalignment of the golf club head results in less than optimum face response characteristics. 
   In addition, an important criterion in selecting a golf club is the “feel” of the club when the club face contacts the golf ball. One of the factors contributing to the “feel” of the golf club is the stiffness of the club face. Because no two golfers are the same, the “feel” of the club preferred by one golfer might be different from that preferred by another golfer. However, golf club manufacturers have been constrained to manufacture sets of golf clubs with a fairly uniform stiffness. Thus, golfers have been limited in their choices of clubs with respect to the stiffness of the golf club. 
   Accordingly, what is needed is a golf club head, a method for manufacturing the golf club head, and a method for tuning the golf club head that permits adjusting the stiffness and the face response characteristics of the golf club head. 
   SUMMARY OF THE INVENTION 
   The present invention satisfies the foregoing need by providing a golf club head and a method of tuning the golf club head using a magnetic field. In accordance with one embodiment, the present invention includes a golf club head comprising a body wherein the body has a front body surface, a heel end, a toe end, a sole extending between lower portions of the heel and the toe ends, and a top portion extending between upper portions of the heel and toe ends. A face plate having first and second surfaces is coupled to the body. 
   In accordance with another embodiment, the present invention comprises a golf club head comprising a body having a cavity, a first body surface, a heel end, a toe end, a sole extending between lower portions of the heel and the toe ends, a top portion extending between upper portions of the heel and toe ends, and a detachable face plate coupled to the body, the detachable face plate having first and second surfaces. 
   In accordance with yet another embodiment, the present invention includes a method of tuning a golf club head having a body which has a cavity, a heel end, a toe end, a sole extending between lower portions of the heel and the toe ends, a top portion extending between upper portions of the heel and toe ends, a back surface extending between the heel end and the toe end, and a front surface extending between the heel end and the toe end. At least one magnet having first and second poles is provided in the cavity and at least one magnet having first and second poles is coupled to the detachable face plate. The face plate is coupled to the body. The distance between the one or more magnets in the cavity and the one or more magnets coupled to the detachable face plate is set to give the golf club head the desired face response characteristics. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates a golf club including a putter head in accordance with an embodiment of the present invention; 
       FIG. 2  illustrates a cross-sectional view of the putter head with a face plate taken along lines  2 - 2  in  FIG. 1 ; 
       FIG. 3  is front view of the face plate shown in  FIGS. 1 and 2 ; 
       FIG. 4  illustrates a golf club including a putter head in accordance with another embodiment of the present invention; and 
       FIG. 5  is a cross-sectional view of the putter head taken along lines  4 - 4  in  FIG. 4 . 
   

   DESCRIPTION OF THE INVENTION 
     FIGS. 1 and 2  depict different views of a golf club in accordance with an embodiment of the present invention. For the sake of clarity,  FIGS. 1 and 2  are described together. Briefly,  FIG. 1  illustrates a golf club  10  including a club head such as a putter head  12  and a shaft  14 .  FIG. 2  illustrates a cross-sectional top view of putter head  12  taken along section line  2 - 2 . Putter head  12  is connected to one end of the shaft  14  and a grip  16  is mounted on an opposing end of shaft  14 . Suitable materials for shaft  14  include titanium, fiberglass, aluminum, steel, graphite, plastic, and wood, among others. Although golf club  10  is shown as having a putter head  12 , it could have an iron-type head or a wood-type head. 
   Putter head  12  includes a body  18  and a hosel  20 . The hosel  20  has a bore  22  for receiving one end of shaft  14  (shown in  FIG. 1 ). Body  18  has a heel end  24  spaced apart from a toe end  26 . A sole  28  extends from a lower portion of heel end  24  to a lower portion of toe end  26  and a top portion or rail  30  extends from an upper portion of heel end  24  to an upper portion of toe end  26 . Body  18  has a back surface  32  that extends between heel end  24  and toe end  26  along a back or rear portion of body  18 . Body  18  further includes a front surface  34  that extends between heel end  24  and toe end  26 . Hosel  20  includes a neck  21  connected to heel end  24  of body  18 . Putter head  12  may be formed by casting, machining from solid castings, or the like. Suitable materials for putter head  12  include, but are not limited to, stainless steel, titanium, aluminum, nickel, alloys of titanium, alloys of aluminum, alloys of nickel, and the like. 
   A cavity  40  (shown in  FIG. 2 ) having a cavity surface  41  extends from front surface  34  into body  18 . Cavity  40  can be formed by techniques such as, for example, molding, machining, and the like. Guide members  42  and  44  extend from back surface  32  through front surface  34 . By way of example, guides  42  and  44  are pins. An L-shaped stop  46  extends from toe end  26  of body  18  over pin  42  and an L-shaped stop  48  extends from heel end  24  of body  18  over pin  44 . They prevent face plate  72  and body  18  from becoming uncoupled from each other. Although L-shaped stops  46  and  48  are shown as being spaced apart from guide pins  42  and  44 , respectively, this is not a limitation of the present invention. L-shaped stops  46  and  48  may contact guide pins  42  and  44 , respectively. Stops  46  and  48  are not limited to being L-shaped. 
   Threaded holes  50 ,  52 , and  54  are formed in body  18  and extend from back surface  32  to cavity surface  41 . In accordance with one embodiment, three holes  50 ,  52 , and  54  are formed in body  18 . However, the number of holes formed in body  18  is not a limitation of the present invention. There may be more than three holes or fewer than three holes. Magnets  60 ,  62 , and  64  are connected to the ends of screws  66 ,  68 , and  70 , respectively, using an adhesive material  65  such as, for example, an epoxy adhesive. Alternatively, magnets  60 ,  62 , and  64  are connected to respective screws  66 ,  68 , and  70  using techniques such as soldering, braising, welding, frictionally fitting a portion of the screw into a hole in the magnet, or the like. Preferably, the same poles of each magnet  60 ,  62 , and  64  are connected to screws  66 ,  68 , and  70 . For example, screws  66 ,  68 , and  70  are connected to the magnetic south poles of magnets  60 ,  62 , and  64 , respectively. Thus, the magnetic north poles of magnets  60 ,  62 , and  64  face away from cavity surface  41 . Screws  66 ,  68 , and  70  are screwed into respective holes  50 ,  52 , and  54 . 
   Face plate  72  has a first or front surface  74 , a second or back surface  76 , and L-shaped ends  78  and  80 , which are comprised of legs  82  and  84  and base portions  86  and  88 , respectively. Briefly referring to  FIG. 3 , a front view of face plate  72  is illustrated. What is shown in  FIG. 3  is front surface  74  and ends  78  and  80 . Creases  90  and  92  indicate the locations of legs  82  and  84  of L-shaped ends  78  and  80 , respectively. Base portions  86  and  88  have openings  92  and  94  through which guide pins  42  and  44  are inserted. Suitable materials for face plate  72  include non-ferrous-materials, wood, plastics, ceramics, and metals. 
   Referring again to  FIG. 2 , magnets  100 ,  102 , and  104  are attached to back surface  76  of plate  72 . In accordance with one embodiment, the magnetic south poles of magnets  100 ,  102 , and  104  are attached to back surface  76  using an adhesive material  77  such as, for example, an epoxy adhesive. Thus, the magnetic north poles of magnets  100 ,  102 , and  104  face toward cavity surface  41  and toward magnets  60 ,  62 , and  64 , and the north poles of magnets  60 ,  62 , and  64  face the north poles of magnets  100 ,  102 , and  104 , respectively. Magnet  60  is spaced apart from magnet  100  by a distance D 1 , magnet  62  is spaced apart from magnet  102  by a distance D 2 , and magnet  64  is spaced apart from magnet  104  by a distance D 3 . 
   Although the magnets have been shown and described as being oriented such that the north poles of magnets  60 ,  62 , and  64  face the north poles of magnets  100 ,  102 , and  104 , respectively, this is not a limitation of the present invention. For example, the magnets may be oriented so that the south poles of magnets  60 ,  62 , and  64  face the south poles of magnets  100 ,  102 , and  104 , respectively, i.e., magnets  60 ,  62 , and  64  are oriented to repel magnets  100 ,  102 , and  104 , respectively. Alternatively, magnets  60  and  64  may be oriented so that their north poles face the north poles of magnets  100  and  104 , respectively, while magnets  62  and  102  are oriented so that the north pole of magnet  62  faces the south pole of magnet  102 . In other words, magnets  60  and  64  repel magnets  100  and  104 , respectively, while magnets  62  and  102  attract each other. In yet another alternative, magnets  60  and  62  may be oriented so that their north poles face the north poles of magnets  100  and  102 , respectively, while magnets  64  and  104  are oriented so that the north pole of magnet  64  faces the south pole of magnet  104 . In other words, magnets  60  and  62  repel magnets  100  and  102 , respectively, while magnets  64  and  104  attract each other. Alternating the polarity of the magnets allows for a broader range of responses. It should be understood that the combination of the magnetic orientations of the magnets is not a limitation of the present invention. 
   In operation, face plate  72  is positioned on body  18  such that guide pin  42  is inserted into opening  92  and guide pin  44  is inserted into opening  94 . Guide pins  42  and  44  help hold face plate  72  in proper position. Because the north poles of magnets  60 ,  62 , and  64  face the north poles of magnets  100 ,  102 , and  104 , the magnets repel each other and push face plate  72  against stops  46  and  48 , thereby changing the dampening effect on the face of the putter head. The magnitudes of the repulsive forces are dependent on distances D 1 , D 2 , and D 3 , which are adjusted by turning screws  66 ,  68 , and  70 . Thus, screws  66 ,  68 , and  70  and holes  50 ,  52 , and  54  cooperate to form a means for adjusting distances D 1 , D 2 , and D 3 . Distances D 1 , D 2 , and D 3  are tuned to provide each individual golfer with his or her desired “feel.” For example, a golfer may desire a putter head with a stiffer face than a typical putter head. Thus, the golfer can adjust screws  66 ,  68 , and  70  to give putter head  12  the desired stiffness. 
     FIGS. 4 and 5  depict different views of a golf club in accordance with another embodiment of the present invention. For the sake of clarity,  FIGS. 4 and 5  are described together. Briefly,  FIG. 4  illustrates a golf club  10 A including a putter head  12 A and a shaft  14 .  FIG. 5  illustrates a cross-sectional top view of putter head  12 A taken along section line  4 - 4 . It should be noted that the difference between the embodiment shown in  FIGS. 4 and 5  and the embodiment shown in  FIGS. 1 and 2  is that body  18 A of putter head  12 A has pedestals  110 ,  112 , and  114  for coupling to magnets  60 ,  62 , and  64 . Accordingly, common reference numbers between  FIGS. 4 and 5  and  FIGS. 1 and 2  have been preserved. Putter head  12 A is connected to one end of a shaft  14  and a grip  16  is mounted on an opposing end of shaft  14 . Although golf club  10 A is shown as having a putter head, it could have an iron-type head or a wood-type head. 
   Putter head  12 A includes a body  18 A and a hosel  20 , which has a bore  22  for receiving one end of shaft  14  (shown in  FIG. 1 ). Body  18 A has a heel end  24  spaced apart from a toe end  26 . A sole  28  extends from a lower portion of heel end  24  to a lower portion of toe end  26  and a top portion or rail  30  extends from an upper portion of heel end  24  to an upper portion of toe end  26 . Body  18 A has a back surface  32 A that extends between heel end  24  and toe end  26  along a back or rear portion of body  18 A. Body  18 A further includes a front surface  34  that extends between heel end  24  and toe end  26 . Hosel  20  includes a neck  21  connected to heel end  24  of body  18 . Putter head  12 A may be formed by casting, machining from solid castings, or the like. Suitable materials for putter head  12 A include, but are not limited to, stainless steel, titanium, aluminum, nickel, alloys of titanium, alloys of aluminum, alloys of nickel, and the like. 
   A cavity  40  (shown in  FIG. 5 ) having a cavity surface  41  extends from front body surface  34  into body  18 A. Cavity  40  can be formed by techniques such as, for example, molding, machining, and the like. Guides  42  and  44  extend from back surface  32 A through front surface  34 . By way of example, guides  42  and  44  are pins. An L-shaped stop  46  extends from body  18 A over pin  42  and an L-shaped stop  48  extends from body  18 A over pin  44 . They prevent face plate  72  and body  18 A from becoming uncoupled. Although L-shaped stops  46  and  48  are shown as being spaced apart from guide pins  42  and  44 , respectively, this is not a limitation of the present invention. L-shaped stops  46  and  48  may contact guide pins  42  and  44 , respectively. Stops  46  and  48  are not limited to being L-shaped. 
   Pedestals  110 ,  112 , and  114  are formed in body  18  and extend from cavity surface  41  into cavity  40 . In accordance with one embodiment, body  18 A has three pedestals  110 ,  112 , and  114 . However, the number of pedestals formed from body  18 A is not a limitation of the present invention. There may be more than three pedestals or fewer than three pedestals. Magnets  60 ,  62 , and  64  are connected to the ends of pedestals  110 ,  112 , and  114 , respectively, using an adhesive material such as, for example, epoxy adhesive  65 . Alternatively, magnets  60 ,  62 , and  64  are connected to respective pedestals  110 ,  112 , and  114  using techniques such as soldering, braising, welding, or the like. Preferably, the same poles of each magnet  60 ,  62 , and  64  are connected to pedestals  110 ,  112 , and  114 . For example, pedestals  110 ,  112 , and  114  are connected to the magnetic south poles of magnets  60 ,  62 , and  64 , respectively. Thus, the magnetic north poles of magnets  60 ,  62 , and  64  face away from cavity surface  41 . 
   Like the embodiment described with reference to  FIGS. 1 and 2 , the orientation of the magnetic poles of magnets  60 ,  62 ,  64 ,  100 ,  102 , and  104  is not a limitation of the present invention. For example, the magnets may be oriented so that the south poles of magnets  60 ,  62 , and  64  face the south poles of magnets  100 ,  102 , and  104 , respectively. Alternatively, magnets  60  and  64  may be oriented so that their north poles face the north poles of magnets  100  and  104 , respectively, while magnets  62  and  102  are oriented so that the north pole of magnet  62  and faces the south pole of magnet  102 , i.e., magnet  60  repels magnet  100 , magnet  64  repels magnet  104 , and magnet  62  attracts magnet  102 . In yet another alternative, magnets  62  and  64  may be oriented so that their north poles face the north poles of magnets  102  and  104 , respectively, while magnets  60  and  100  are oriented so that the north pole of magnet  60  faces the south pole of magnet  100 . In other words, magnets  62  and  64  repel magnets  102  and  104 , respectively, while magnets  60  and  100  attract each other. Alternating the polarity of the magnets allows for a broader range of responses. An advantage of the embodiment described with reference to  FIGS. 4 and 5  is that the distance between magnets  60 ,  62 , and  64  and magnets  100 ,  102 , and  104 , respectively, can be set at the factory thereby facilitating the production of large quantities of golf clubs having a predetermined stiffness. This allows a golfer to select a golf club with a desired stiffness without a subsequent adjustment.