Patent Publication Number: US-2007117644-A1

Title: Golf club

Description:
The present invention relates generally to a golf club. In particular, the present invention relates to a golf dub in which the golf dub head comprises granite or a natural, granite-like stone, a composite, or a similar material. More particularly, the present invention relates to a golf putter.  
      Golf clubs are well known and include a golf dub head, shaft, and grip. The head includes a front strike face. Heads typically have an intended contact region centrally positioned on the strike face and commonly referred to as the “sweet spot.” A golf ball, upon contact with the sweet spot of the strike face, will typically and consistently travel a distance and in a direction that is directly proportional to the speed of the dub head at impact.  
      Conversely, when a user contacts the golf ball at a position away from the intended contact region, commonly referred to as a “mis-hit”, the ball will typically travel a distance that is significantly less than intended, or at an angle to the desired direction, that is, a “hook” or “slice”, or both, than that of a ball contacted at the intended contact region of the strike face. Moreover, the distance loss, hook, or slice can be variable and unpredictable. In an effort to increase the size of the sweet spot of a golf club, many heads are configured with various combinations of weighting to change the golf club&#39;s moment of inertia. A golf dub with an increased moment of inertia is more resistant to twisting during a mis-hit and, therefore, enables the performance of a mis-hit ball to more closely match the performance of a ball contacted at the sweet spot. However, weighting alone generally does not eliminate the distance loss or misdirection that typically occurs as a result of a mis-hit.  
      When a user contacts a golf ball with a golf club at the intended contact region of the strike face, the club typically generates an amount of audible and vibrational energy that provides the user with sound indicative of solid contact with the ball and a corresponding “feel”. In efforts to improve the feel of a golf dub upon impact, many heads include an insert, typically of uniform thickness, mounted into the strike face and/or within the head. Depending upon the golf dub, such inserts may be harder or softer than the material out of which the head itself is made. For example, in the case of a driver, the head is typically made of wood and the insert is typically made of a hard metal such as, for example, steel or titanium. In the case of a putter, the head is typically made of metal and the insert is typically made of a material which is softer such as, for example, plastic or polymer.  
      A variety of golf dub heads have been developed which are intended to reduce the number of mis-hits, improve the feel of the golf club stroke upon impact of the head with the ball, or both. For example, U.S. patent Publication No. 2003/0045372 A1 discloses a putter having an insert of variable thickness that increases the size of the putter&#39;s sweet spot. U.S. Pat. No. 6,533,680 B2 discloses a putter having an improved weight distribution which alters the head is center of gravity in order to reduce the number of mis-hits. U.S. patent Publication No. 2003/0054899 A1 discloses a golf putter in which the putter head is made of a strengthened, triangular shaped, kiln formed glass.  
      However, there is still a need for improved head design in order to further reduce the number of mis-hits and improve the feel when the golf club strikes the ball. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The accompanying drawings illustrate one embodiment of the present invention in which the golf dub is a putter.  
       FIG. 1  is a schematic, cross-sectional front view of a golf dub of this invention.  
       FIG. 2  is a schematic top view of a club head of this invention.  
       FIG. 3  is a cross-sectional side view of a club head of this invention. 
    
    
      The following description generally applies to a golf club of this invention wherein the golf club is a putter. However, the description can apply equally well to other types of golf clubs such as, for example, drivers.  
       FIG. 1  illustrates a schematic, cross-sectional, front view of a putter  10  for a right-handed golfer. The putter  10  includes a putter head  13 , a shaft  14 , and a grip  16 . The putter head  13  is an elongate body with a toe portion  12  and a heel portion  15 . The putter head  13  includes a main body  18  and an insert  20 .  
      The shaft  14  is an elongate tube having a distal end  22 , which is coupled to the dub head  13 , and a proximal end  24 , which is slidably connected to a grip  16 . Optionally, the grip  16  may be permanently connected to the shaft  14  or may be integrated into the shaft  14 . The shaft  14  is made of a generally lightweight, strong material, preferably graphite or steel Alternatively, the shaft can be formed of other materials, such as, for example, other metals or alloys, composites, or wood. In one embodiment, the shaft  14  includes an inward taper that generally extends from the proximal end  24  to the distal end  22 . Alternatively, the shaft  16  can be formed having a uniform diameter along its length.  
      The grip  16  is a conventional handle structure of generally hollow construction. The grip  16  has an open end configured for slidably receiving the proximal end  24  of the shaft  14 . The grip  16  is typically formed of a generally soft resilient material such as, for example, rubber, polyurethane, leather, a thermoplastic, or an elastomer. In an alternative embodiment, the grip  16  can be formed of two or more layers of material. In such cases, the layers may be constructed of the same or of different materials. In a further embodiment, the grip  16  can be formed by wrapping of one or more tapes about the proximal end  24  of the shaft  14 . In an additional alternative embodiment, the grip  16  is formed integrally with the shaft  14  such that the grip  16  and the shaft  14  form a “one-piece” unit of uniform construction. In another further embodiment, the grip  16  is formed of wood, a composite material, or a combination thereof.  
       FIGS. 2 and 3  illustrate the main body  18  and the insert  20  of the putter head  13  in greater detail. The main body  18  includes a toe portion  12 , a heel portion  15 , a sole portion  33 , a top portion  37 , and a front face  35   a . Front face  35   a  and the corresponding front face  35  of the insert  20  will collectively be referred to as front face  35  when referring to the head  13  as a whole. The front face  35  may be at 90 degrees to the sole portion  33 . That is, when the putter is placed on a flat, horizontal surface, the front face  35  is vertical. In a preferred embodiment, the front face  35  is at an angle, referred to as the “loft angle”,  34  to the sole portion  33 . The loft angle  34  is typically less than 10 degrees, preferably between zero and seven degrees, more preferably between 4 and 4.5 degrees, and most preferably 4.5 degrees, measured counterclockwise from the 90 degree angle of the front face  35  when the sole portion  33  is on a flat, horizontal surface and the club is oriented as in  FIG. 3 .  
      The main body  18  contains a recess  25 , extending rearwardly from the front face  35  and defined by sidewalls  21 , rear wall  23 , and top wall  39 , extending from the toe portion  12  to the heel portion  15  and from the top portion  37  to the sole portion  33 . The recess  25  is configured to receive the insert  20 . The recess  25  may optionally have a bottom wall opposite the top wall  39  in the sole portion  33 . In this optional embodiment, the recess  25  is configured to enclose all but the front face  35  of the insert  20 .  
      Referring again to  FIGS. 2 and 3 , the main body  18  may optionally contain a second recess  32  extending rearwardly from the rear wall  23  toward the back face  31 . This second recess  32  is defined by sidewalls  320 , rear wall  322 , top wall  324 , and bottom wall  326 . The second recess  32  is configured to receive a weight  328 . The weight  328  increases the moment of inertia of the putter head  13  and increases its resistance to twisting in response to mis-hit shots. The weight  328  substantially fills the second recess  32  and may be any dense material such as, for example, a metal such as, for example, steel or lead, or a dense composite material. In a preferred embodiment, the weight  328  is lead. The weight of the weight  328  may vary depending upon the total weight of the putter  10 , more particularly the putter head  13 . This, in turn, may vary with the weight of the insert  20  in order to give the putter  10  the weight distribution desired by the golfer. The optional weight  328  typically will weigh between 2 and 6 ounces (56 to 168 grams), preferably between 3 and 5 ounces (84 to 140 grams), most preferably 4 ounces (112 grams). In one embodiment, the second recess  32  is configured in such a manner that the weight  328  is poured into the recess  32  while in a liquid state. In such an embodiment, the weight  328  completely fills the recess  32 . In an alternative embodiment, the weight  328  is held in the recess  32  by an adhesive or an adhesive agent. In a preferred embodiment, the recess  32  is sized such that it is completely filled with weight  328 .  
      For purposes of this invention, all described ranges are inclusive and combinable. The term “cm” means centimeters.  
      The top portion  37  may optionally incorporate a sight line extending from the front face toward the back face, a raised or recessed dot, or other indicator of the location of the optimal strike point on the face  35 . This sight line, dot, or indicator is typically made of a material with a color contrasting with that of the main body  18 . The sight line may also be engraved into the top portion  37 . The sight line assists the user in identifying the intended strike point of the golf dub head, particularly when the golf club is a putter wherein the sight line assists the user in properly lining up or measuring his or her putt.  
      Again, referring to  FIGS. 2 and 3 , upwardly extending from recess  380  in insert  20  through opening  26  in top portion  37  is a means  38  for connecting the club head  13  to the distal end  22  of shaft  14 . Such means  38  includes, for example, a hollow or solid rod, a stud, a bolt, a screw, a hostel, or similar means. In a preferred embodiment, the means  38  is an extension configured for slidably engaging the distal end  22  of the shaft  14 . In such cases, the distal end  22  may engage means  38  by extending into the inside, if the means  38  is hollow, or over the outside of the means  38 . The distal end  22  of shaft  14  may be attached to the means  38  by a variety of methods known to those in the golf club art including, for example, using a adhesive or adhesive agent, welding, by friction alone, by means of a threaded joint, or an expansion connector. Optionally, the distal end  22  of shaft  14  may extend into recess  380  and be affixed directly to insert  20 . The means  38  may be affixed to the insert  20  using a variety of methods such as, for example, using an adhesive or adhesive agent, careful fitting of the means  38  into the recess  380  such that the means  38  is held by friction alone, or through the use of an expansion connector or threaded joint. Optionally, the recess  380  may extend entirely through insert  20  and means  38  may be affixed to the insert  20  using an alternate attachment method such as, for example, a nut, bolt, or screw. As a further option, an additional recess may be incorporated into the club head  13  from the side or back of the club head extending to the recess  380 . In such cases, the means  38  may be held in place in the recess  380  by means of a fastener such as, for example, a rod, screw, bolt, or Allen screw. In such cases, the additional recess may be threaded, to accept the bolt or Allen screw, or unthreaded, to accept a screw, rod, or similar fastener. In another alternate embodiment, the club head  13  may be connected to the distal end  22  of shaft  14  directly to the main body  18  rather than to the insert  20 .  
      In the embodiment of this invention illustrated in  FIGS. 1-3 , the means  38  engages the distal end  22  of shaft  14  at an angle  11 . In one embodiment, this angle is 180 degrees. In other words, the shaft  14  is straight. In such cases, the recess  380  and means  38  are configured at an appropriate angle in insert  20  to accept the straight shaft  14 . In a preferred embodiment, the shaft  14  is angled. In a more preferred embodiment, the angle  11  is no greater than 20 degrees from vertical when the sole portion  33  is on a flat surface. In another preferred embodiment, the bend incorporating angle  11  is within 5 inches (12.7 cm.) of the club head  13 . In a further embodiment, angle  11  is adjustable utilizing any of a variety of means for adjusting the angle. When adjustable, angle  11  is preferably adjustable from 10 to 20 degrees from vertical.  
      Typically, insert  20  substantially fills the recess  25  and is connected to the side walls  21 , top wall  39 , rear wall  23 , and, when present, the optional bottom wall.  
      In one embodiment of this invention, insert  20  is made of a hard natural or synthetic stone material. Preferably, the stone is a natural stone material. For purposes of this invention, “hard” means that the stone material has a hardness greater than 5 on the commonly used Measurement of Hardness Scale (“MOHS”). In the MOHS talc has a hardness of 1 and diamond a hardness of 10. In one preferred embodiment, the hardness of the stone material is from 6 to 7. In a second preferred embodiment, the stone material is a natural igneous stone. In a more preferred embodiment, the igneous stone is granite. Granite primarily comprises quartz, feldspar, and other minor components. A typical granite will contain 35% by weight quartz (MOHS=7) and 45% by weight feldspar (MOHS=6) along with minor components, primarily potassium and mica. In an alternate embodiment, the granite meets the structural specifications of the National Building Granite Quarries Association, Washington, D.C., USA. Such specifications include the following based upon American Society of Testing and Materials (ASTM) tests C97, C99, C170, and C880 (all tests conducted dry on the strongest plane of the granite):  
                                                      Absorption by weight   0.40%           Min. density   160 lbs/CuFt (2,560 kg/m3)           Min. Modulus of Rupture   1,500 psi (10.34 Mpa)           Min. Compressive Strength   19,000 psi (131 Mpa)           Min. Flexural Strength   1,200 psi (8.27 Mpa)                      
 
      The insert  20  can be a single stone or multilayered in which the layers are made up of the same stone or type of stone or different stones. In an alternate embodiment, the insert  20  can be multilayered with one or more layers made up of a synthetic or natural stone material and one or more layers made up of an alternate material. Such alternate materials include, for example, metals such as, for example, titanium, bronze, or copper; composites such as, for example, a ceramic, a polymer, or other plastic material; or wood. Preferably, the insert  20  is a single stone. For aesthetic reasons, the insert  20  is preferably granite with a pleasing color combination or mineral grain pattern.  
      The hard stone, particularly when it is also a dense stone such as granite, provides a “soft” feel to the golfer upon impact of the golf club with the ball. This soft feel is further improved by the make-up of the main body  18  of the head  13 . The main body  18  can be made of a variety of materials such as, for example, a metal such as, for example, titanium, bronze, or copper; a composite such as, for example, a ceramic, a polymer, or other plastic material; or wood. In a preferred embodiment, the main body  18  is wood. In an alternate preferred embodiment, the wood is a hardwood. Again, for aesthetic reasons, it is preferred that the wood have a pleasing color and grain structure to complement the insert  20 .  
      In an alternate embodiment of the head  13 , the insert  20  extends forward from the main body  18  such that only the front face  35  will contact the ball when the club strikes the ball. In a further alternate embodiment, the insert  20  is constructed in such a manner that the front face  35  extends up to, or beyond the side walls  21 , the top wall  39 , or both. In one version of this alternate embodiment, the insert  20  itself forms the toe portion  12  and the heel portion  15  of the head  13 . In this embodiment, the “recess”  25  is defined by the real wall  23  and, optionally, the top wall  39 . In still a further embodiment, the insert  20  extends from the top portion  37  to the sole portion  33 . In this embodiment, the “recess”  25  in the main body  18  is defined only by the rear wall  23 . In this alternate embodiment, the insert  20  is enclosed only by the rear wall. In this further alternate embodiment, again, only the front face will contact the ball when the dub strikes the ball. The height and width of insert  20  may vary from bottom to top and from side to side within the recess. Thus, in the various embodiments of this invention, the recess  25  is defined by anywhere from one to five of the various walls. Furthermore, each of the walls may independently partially or fully cover the corresponding side or sides of the insert  20 .  
      The main body edges  36 , the insert edges  30 , or both may be square, rounded (as depicted in  FIG. 3 ), or have any of a number of decorative profiles depending upon the desire of the user. Preferably the edges are rounded.  
      In a typical example of one embodiment of a putter head  13  of this invention, the head measures 4.75 inches (12.2 cm) from the toe portion  12  to the heel portion  15 , 2 inches (5.1 cm) from the front face  35  to the back face  31 , and 1.0 inch (2.5 cm) from the top portion  37  to the sole portion  33 . The recess  25  typically measures 3.75 inches (9.6 cm) between the side walls and 1.25 inches (3.2 cm) from the front face  35  of the insert  20  to the rear wall  23 , and has a depth from the sole portion  33  to the top wall  39  of 0.875 inches (2.2 cm). The opening  26  is typically located 1.125 inches (2.9 cm) from the heel portion  15  and 0.8125 inches (2.1 cm) from front face  35 . Opening  26  is typically 0.3125 inches (0.9 cm) in diameter. In actual practice, these measurements may vary considerably due to variations in the overall shape of the head  13 , the materials used in construction of the insert  20  and the main body  18 , the desired overall weight of the head  13 , and other considerations and desires of the user. However, in practice, the length from the toe portion  12  to the heel portion  15  will not exceed 5 inches (12.7 cm) and the total volume of the head  13  will not exceed 470 cubic cm. In another example of a putter head  13  of this invention, the length from the toe portion  12  to the heel portion  15  is twice the depth from the front face  35  to the back face  31 .  
      In an alternate embodiment of this invention, the entire head  13  comprises granite. This embodiment can be viewed as one in which the insert  20  also comprises the main body  18  as a single unit. In this embodiment, the head  13  may be constructed of a single stone may be multilayered.  
      In one embodiment of this invention, the overall minimum length of the golf dub  10  is at least 18 inches (45.72 cm) measured from the end of the grip  16  along the axis of the shaft  14  or a straight line extension thereof, to the sole portion  33  and the overall maximum length of the golf club  10  is 48 inches (121.92 cm) measured from the ground plane to the end of the grip  16  with the shaft  14  at a 60-degree lie angle (i.e. to the ground).  
      The advantage of a golf club of this invention is in its balance. By modifying the size, shape, and weight of the main body  18 , the insert  20 , and the optional weight  328 , as well as the positioning of the means  38  and the length and angle of the shaft  14  the user can obtain a golf club which is balanced such that the face is square with the ball upon impact. In addition, the combination of the insert  20  with the main body  18  provides a golf club with improved feel when the club strikes the ball.  
      While the preferred embodiments of the present invention have been described and illustrated, numerous departures therefrom can be contemplated by persons skilled in the art.