Abstract:
A wood type golf club head having a plurality of interior recesses is disclosed herein. The plurality of interior recesses are preferably formed in a body of the golf club head and remove mass from the body to be used elsewhere on the golf club head to increase the inertial properties of the golf club head.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
       [0001]    The Present Application claims priority upon U.S. Provisional Application No. 61/234,384 filed on Aug. 17, 2009. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of the Invention 
         [0004]    The present invention relates to a wood-type golf club head. More specifically, the present invention relates to a wood-type golf club head with components that have been selectively lightened to reduce mass of the components. 
         [0005]    2. Description of the Related Art 
         [0006]    The prior art discloses various golf club heads. 
         [0007]    Existing wood designs, particularly drivers, generally seek to achieve a reduced structural weight fraction in the shell portion (i.e., sole, crown, ribbon) of the head so additional weight can be available for other design aspects (weighting, styling, etc). Reduced thickness can be achieved by forming and welding high strength titanium sheet stock, but it&#39;s difficult to locally and purposefully vary thickness to minimize weight using this construction. Local and purposeful thickness variation is readily achieved using the casting method of construction, but cast titanium is generally lower strength and requires increased overall shell thickness for adequate durability. 
         [0008]    Further, the shell portion of the head significantly influences the sound (when struck by a ball). The formed sheet construction method is very limited in affecting sound since features such as local thickening and local webbing (which would influence sound) are not practical with this construction. Such features are readily added to shells made using cast construction, but again, minimum weight is difficult to achieve with this method. 
         [0009]    Current wood heads struggle to achieve both minimum structural weight and pleasing sound at impact. 
       BRIEF SUMMARY OF THE INVENTION 
       [0010]    The present invention provides a solution to the problem. 
         [0011]    The present invention seeks to achieve a reduced structural weight fraction while also providing a means for affecting sound radiating from the sole and/or crown portions of the shell. 
         [0012]    The present invention preferably includes of the introduction of a plurality of small diameter partial holes to the inside surface (IML) of a shell constructed using the sheet formed/welded construction. The holes are partial in that they originate on the IML surface and proceed into, but not thru the thickness of the shell. In other words, these are not “thru-holes.” Being non-thru holes avoids adding complexity to finishing (polishing, painting, etc) of the exterior surface. Also, placing the holes on the interior surface avoids a likely undesirable cosmetic appearance. Also, use of non-thru holes avoids the need to seal the holes for prevention of moisture ingression. 
         [0013]    The holes may be patterned in such a manner as to uniformly or locally reduce the effective density of the shell for purposes of achieving minimum structural weight fraction for the shell. 
         [0014]    Further, the holes may be patterned in such a way as to uniformly or locally affect the stiffness/mass ration (√k/m) which in turn affects the resonant frequency and sound during impact. 
         [0015]    A wood head having a body fabricated using formed sheets of metal which are subsequently welded together. Sole and/or crown and/or ribbon portions of the body contain a plurality on non-thru holes originating from the interior surface of the body. 
         [0016]    The wood-type golf club head also preferably includes non-thru holes have a diameter between 0.030″ and 10 microns. The wood-type golf club head also preferably includes non-thru holes penetrate between 50-90% of the local thickness of the shell. The wood-type golf club head also preferably includes non-thru holes are spaced in a pattern such that between 5/25% of the weight of the shell is removed. The wood-type golf club head also preferably includes the method of manufacture of the holes may include drilling, milling, punching, forming, forging, chemical etching, photo etching, water jet and laser. 
         [0017]    The wood-type golf club head also preferably includes a secondary machining operation is required to re-flatten the side of the sheet w/o holes (ie fly cut). The wood-type golf club head also preferably includes the non-thru holes are applied to the sheet material in the flat state prior to forming in the general shape of the shell. 
         [0018]    A pattern of holes are applied to the interior surface of the crown and/or sole portion of the head. The holes are non-thru holes and are not noticeable from the exterior surface of the head. The holes may be located and patterned (spaced) such that they result in reduced shell weight such that they positively affect the resonant response of the shell during impact and thus affect sound. 
         [0019]    A wood with a selectively lightened shell by means of addition of a plurality of non-thru holes added to the interior surface of the body for purpose of weight reduction and/or sound refinement. 
         [0020]    A driver head having a body fabricated using formed sheets of titanium which are subsequently welded together. Sole and/or crown and/or ribbon portions of the body contain a plurality of non-thru holes originating from the interior surface of the body. 
         [0021]    Preformed construction is formed/molded sheet i.e., “multi-piece” construction. 
         [0022]    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 
         [0023]      FIG. 1  is a top perspective view of a golf club head. 
           [0024]      FIG. 2  is a rear top perspective view of the golf club head of  FIG. 1 . 
           [0025]      FIG. 2A  is an isolated view of circle A of  FIG. 2 . 
           [0026]      FIG. 2B  is an isolated cross-sectional view of line B-B of  FIG. 2A . 
           [0027]      FIG. 3  is bottom plan view of the golf club head of  FIG. 1 . 
           [0028]      FIG. 4  is a top plan view of the golf club head of  FIG. 1 . 
           [0029]      FIG. 4A  is a cross-sectional view of the golf club head along line A-A of  FIG.4 . 
           [0030]      FIG. 5  is a toe side view of the golf club head of  FIG. 1 . 
           [0031]      FIG. 6  is a heel side view of the golf club head of  FIG. 1 . 
           [0032]      FIG. 7  is an exploded top perspective view of the golf club head. 
           [0033]      FIG. 8  is an exploded bottom perspective view of the golf club head. 
           [0034]      FIG. 9  is a front plan view of a golf club head illustrating the Z axis and Y axis through a center of gravity of the golf club head, and also the width of the golf club head. 
           [0035]      FIG. 10  is a heel side view of a golf club head illustrating the Z axis and X axis through a center of gravity of the golf club head, and also the height and length of the golf club head. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0036]    As shown in  FIGS. 1-10 , in a preferred embodiment, a golf club head  40  is generally composed of three primary components, a major body  50 , a striking plate insert  55  and minor body  60 . The minor body  60  has a crown section  62  and a ribbon section  64 . The club head  40  may also be partitioned into a heel end  66  nearest the shaft  48 , a toe end  68  opposite the heel section  66 , and an aft end  70 . As shown in  FIGS. 2A ,  2 B and  4 A, the golf club head  40  has a plurality of interior recesses  99  in the major body  50  and the minor body  60 . The plurality of interior recesses  99  reduce the mass of the golf club head  40  while maintaining the structural integrity of the golf club head  40 . Each of the plurality of recesses  99  preferably has a depth ranging from  50 % to  90 % of the thickness of the major body  50  and the minor body  60 . Each of the plurality of recesses  99  preferably has a diameter ranging from  0 . 030  inch to  10  microns. 
         [0037]    The major body  50  is generally composed of a single piece of metal, and is preferably composed of a cast metal material. More preferably, the cast metal material is a stainless steel material or a titanium material such as pure titanium and titanium alloys such as 6-4 titanium alloy, SP-700 titanium alloy (available from Nippon Steel of Tokyo, Japan), DAT 55G titanium alloy available from Diado Steel of Tokyo, Japan, Ti 10-2-3 Beta-C titanium alloy available from RTI International Metals of Ohio, and the like. Alternatively, the major body may be manufactured through forging, welding, forming, machining, powdered metal forming, metal-injection-molding, electro-chemical milling, and the like. 
         [0038]    The major body  50  generally includes a front wall section  72 , a return section  74  extending laterally rearward from the upper perimeter of the front wall section  72 , a sole section  76  extending laterally rearward from the front wall section  72 , a ribbon section  78  extending upward from the sole section  76 , and a ledge section  80  stepped inward for attachment of the minor body  60 . The front wall section  72  has an opening for placement of the striking plate insert  55  therein. 
         [0039]    The return section  74  extends inward, towards the minor body  60 , and has a general curvature from the heel end  66  to the toe end  68 . The return section  74  has a length from the perimeter  73  of the front wall section  72  that is preferably a minimal length near the center of the front wall section  72 , and increases toward the toe end  68  and the heel end  66 . A distance d represents the length of the return section  74  from the perimeter  73  at the center of the front wall section  72 , a distance d′ from the perimeter  73  at the heel end  66  of the front wall section  72 , and a distance d″ from the perimeter  73  at the toe end  68  of the front wall section  72 . In a preferred embodiment, the distance d ranges from 0.2 inch to 1.5 inches, more preferably 0.30 inch to 1.25 inches, and most preferably from 0.60 inch to 1.0 inch, as measured from the perimeter  73  of the front wall section  72  to the rearward edge of the return section  74 . In a preferred embodiment, the distance d′ ranges from 0.4 inch to 2.00 inches, more preferably 0.50 inch to 1.75 inches, and most preferably from 0.8 inch to 1.50 inches, as measured from the perimeter  73  of the front wall section  72  to the rearward edge of the return section  74 . In a preferred embodiment, the distance d″ ranges from 0.4 inch to 2.25 inches, more preferably 0.50 inch to 2.00 inches, and most preferably from 0.9 inch to 1.50 inches, as measured from the perimeter  73  of the front wall section  72  to the rearward edge of the return section  74 . 
         [0040]    The perimeter  73  of the front wall section  72  is defined as the transition point where the major body  50  transitions from a plane substantially parallel to the front wall section  72  to a plane substantially perpendicular to the front wall section  72 . Alternatively, one method for determining the transition point is to take a plane parallel to the front wall section  72  and a plane perpendicular to the front wall section  72 , and then take a plane at an angle of forty-five degrees to the parallel plane and the perpendicular plane. Where the forty-five degrees plane contacts the major body  50  is the transition point thereby defining the perimeter  73  of the front wall section  72 . 
         [0041]    The golf club head  40  has striking plate insert  55  that is attached to the major body  50  over the opening  32  of the front wall  72 . The striking plate insert  55  is preferably composed of a formed titanium alloy material. Such titanium materials include titanium alloys such as 6-22-22 titanium alloy and Ti 10-2-3 alloy, Beta-C titanium alloy, all available from RTI International Metals of Ohio, SP-700 titanium alloy (available from Nippon Steel of Tokyo, Japan), DAT 55G titanium alloy available from Diado Steel of Tokyo, Japan, and like materials. The preferred material for the striking plate insert  55  is a heat treated 6-22-22 titanium alloy which is a titanium alloy composed by weight of titanium, 6% aluminum, 2% tin, 2% chromium, 2% molybdenum, 2% zirconium and 0.23% silicon. The titanium alloy will have an alpha phase in excess of 40% of the overall microstructure. As shown in  FIG.1 , the striking plate insert  55  typically has a plurality of scorelines  45  thereon. 
         [0042]    As shown in  FIG. 1 , the striking plate insert  55  is preferably welded to the front wall section  72  of the major body  50 , thereby covering the opening  32 . A plurality of tabs, not shown, preferably three, align the striking plate insert  55  for the welding process. Alternatively, the striking plate insert  55  is press-fitted into the opening  32 . 
         [0043]    The minor body  60  is preferably composed of a low density material, preferably a metal or a polymer material. Preferably metals include magnesium alloys, aluminum alloys, magnesium or aluminum material. Exemplary magnesium alloys are available from Phillips Plastics Corporation under the brands AZ-91-D (nominal composition of magnesium with aluminum, zinc and manganese), AM-60-B (nominal composition of magnesium with aluminum and manganese) and AM-50-A (nominal composition of magnesium with aluminum and manganese). If metal, the minor body 60 is preferably manufactured through metal-injection-molding, casting, forming, machining, powdered metal forming, electro chemical milling, and the like. 
         [0044]    The mass of the club head  40  of the present invention ranges from 165 grams to 250 grams, preferably ranges from 175 grams to 230 grams, and most preferably from 190 grams to 205 grams. Preferably, the major body  50  has a mass ranging  from  140  grams to  200 grams, more preferably ranging from 150 grams to 180 grams, yet more preferably from 155 grams to 166 grams, and most preferably 161 grams. The minor body  60  has a mass preferably ranging from 4 grams to 20 grams, more preferably from 5 grams to 15 grams, and most preferably 7 grams. Each stiffening member  122  has a mass preferably ranging from 1 gram to 50 grams, more preferably from 5 grams to 25 grams, and most preferably 10 grams. Additionally, epoxy, or other like flowable materials, in an amount ranging from 0.5 grams to 5 grams, may be injected into the hollow interior  46  of the golf club head  40  for selective weighting thereof. The golf club head preferably has a coefficient of restitution a (“COR”) ranging from 0.81 to 0.875, and more preferably from 0.82 to 0.84. The golf club head preferably has a characteristic time (“CT”) as measured under USGA conditions of 256 microseconds. 
         [0045]    The golf club head  40  preferably has that ranges from 290 cubic centimeters to 600 cubic centimeters, and more preferably ranges from 330 cubic centimeters to 510 cubic centimeters, even more preferably 350 cubic centimeters to 495 cubic centimeters, and most preferably 415 cubic centimeters or 460 cubic centimeters. 
         [0046]      FIGS. 9 and 10  illustrate the axes of inertia through the center of gravity of the golf club head. The axes of inertia are designated X, Y and Z. The X axis extends from the striking plate insert  55  through the center of gravity, CG, and to the rear of the golf club head  40 . The Y axis extends from the toe end  68  of the golf club head  40  through the center of gravity, CG, and to the heel end  66  of the golf club head  40 . The Z axis extends from the crown section  62  through the center of gravity, CG, and to the sole section  76 . 
         [0047]    As defined in Golf Club Design, Fitting, Alteration &amp; Repair, 4 th  Edition, by Ralph Maltby, the center of gravity, or center of mass, of the golf club head is a point inside of the club head determined by the vertical intersection of two or more points where the club head balances when suspended. A more thorough explanation of this definition of the center of gravity is provided in Golf Club Design, Fitting, Alteration &amp; Repair. 
         [0048]    The center of gravity and the moment of inertia of a golf club head  40  are preferably measured using a test frame (X T , Y T , Z T ), and then transformed to a head frame (X H , Y H , Z H ) The center of gravity of a golf club head may be obtained using a center of gravity table having two weight scales thereon, as disclosed in U.S. Pat. No. 6,607,452, entitled High Moment Of Inertia Composite Golf Club, and hereby incorporated by reference in its entirety. 
         [0049]    In general, the moment of inertia, Izz, about the Z axis for the golf club head  40  preferably ranges from 2800 g-cm 2  to 5000 g-cm 2 , preferably from 3000 g-cm 2  to 4500 g-cm 2 , and most preferably from 3750 g-cm 2  to 4250 g-cm 2 . The moment of inertia, Iyy, about the Y axis for the golf club head  40  preferably ranges from 1500 g-cm 2  to 4000 g-cm 2 , preferably from 2000 g-cm 2  to 3500 g-cm 2 , and most preferably from 2400 g-cm 2  to 2900 g-cm 2 . The moment of inertia, Ixx, about the X axis for the golf club head  40  preferably ranges from 1500 g-cm 2  to 4000 g-cm 2 , preferably from 2000 g-cm 2  to 3500 g-cm 2 , and most preferably from 2500 g-cm 2  to 3000 g-cm 2 . 
         [0050]    In general, the golf club head  40  has products of inertia such as disclosed in U.S. Pat. No. 6,425,832, and is hereby incorporated by reference in its entirety. Preferably, each of the products of inertia, Ixy, Ixz and Iyz, of the golf club head  40  have an absolute value less than 100 grams-centimeter squared. Alternatively, the golf club head  40  has a at least one or two products of inertia, Ixy, Ixz and Iyz, with an absolute value less than 100 grams-centimeter squared. 
         [0051]    As shown in  FIGS. 9 and 10 , the width, W, preferably ranges from 4.0 inches to 5.5 inches, and most preferably from 4.75 inches to 5.0 inches. The height, H, preferably ranges from 2.0 inches to 3.0 inches, and most preferably ranges from 2.40 inches to 2.65 inches. The length, L, preferably ranges from 3.5 inches to 4.5 inches, and most preferably from 4.0 inches to 4.25 inches. The golf club head  40  may have an aspect ratio such as disclosed in U.S. Pat. No. 6,338,683 for a Striking Plate For A Golf Club Head, assigned to Callaway Golf Company, and which pertinent parts are hereby incorporated by reference. 
         [0052]    Those skilled in the pertinent art will recognize that other types of golf club heads can be utilized with the present invention, such as cast body two piece golf club heads with a body and attachable striking plate, sole or crown, a multiple-piece construction golf club heads composed of four or more pieces. 
         [0053]    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.