Patent Publication Number: US-2004055696-A1

Title: Method for manufacturing an iron golf club head

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001] Not Applicable  
       FEDERAL RESEARCH STATEMENT  
       [0002] [Not Applicable] 
       BACKGROUND OF INVENTION  
       [0003] 1. Field of the Invention  
       [0004] The present invention relates to manufacturing iron golf clubs. More specifically, the present invention relates to a method for manufacturing a multiple material iron golf club.  
       [0005] 2. Description of the Related Art  
       [0006] Irons are typically composed of a stainless steel or titanium material, and are typically cast or forged. Most golfers desire that their irons have a large sweet spot for greater forgiveness, a low center of gravity to get the ball in the air, a solid sound, reduced vibrations during impact, and a trim top line for appearance. Unfortunately, these desires are often in conflict with each other as it pertains to an iron.  
       [0007] The use of iron club heads composed of different materials has allowed some prior art irons to achieve some of these desires.  
       [0008] One example is U.S. Pat. No. 5,228,694 to Okumoto et al., which discloses an iron club head composed of a stainless steel sole and hosel, a core composed of a bulk molding compound or the like, a weight composed of a tungsten and polyamide resin, and an outer-shell composed of a fiber-reinforced resin.  
       [0009] Another example is set forth in U.S. Pat. Nos. 4,792,139, 4,798,383, 4,792,139 and 4,884,812, all to Nagasaki, et al., which disclose an iron club head composed of stainless steel with a fiber reinforced plastic back plate to allow for weight adjustment and ideal inertia moment adjustment.  
       [0010] Another example is U.S. Pat. No. 4,848,747 which discloses a metal iron club head with a carbon fiber reinforced plastic back plate to increase the sweet spot. A ring is used to fix the position of the back plate.  
       [0011] Another example is set forth in U.S. Pat. Nos. 4,928,972 and 4,964,640 which disclose an iron club head composed of stainless steel with a fiber reinforcement in a rear recess to provide a dampening means for shock and vibrations, a means for increasing the inertial moment, a means for adjusting the center of gravity and a means for reinforcing the back plate.  
       [0012] Another example is U.S. Pat. No. 5,190,290 to Take, which discloses an iron club head with a metal body, a filling member composed of a light weight material such as a plastic, and a fiber-reinforced resin molded on the metal body and the filling member.  
       [0013] Another example is U.S. Pat. No. 5,411,264 to Oku, which discloses a metal body with a backwardly extended flange and an elastic fiber face plate in order to increase the moment of inertia and minimize head vibrations.  
       [0014] Another example is U.S. Pat. No. 5,472,201 to Aizawa et al., which discloses an iron club head with a body composed of stainless steel, a face member composed of a fiber reinforced resin and a protective layer composed of a metal, in order to provide a deep center of gravity and reduce shocks.  
       [0015] Another example is U.S. Pat. No. 5,326,106 to Meyer, which discloses an iron golf club head with a metal blade portion and hosel composed of a lightweight material such as a fiber reinforced resin.  
       [0016] Another example is U.S. Pat. No. 4,664,383 to Aizawa et al., which discloses an iron golf club head with a metal core covered with multiple layers of a reinforced synthetic resin in order to provide greater ball hitting distance.  
       [0017] Another example is U.S. Pat. No. 4,667,963 to Yoneyama, which discloses an iron golf club head with a metal sole and a filling member composed of a fiber reinforced resins material in order to provide greater hitting distance.  
       [0018] The prior art fails to disclose an iron golf club head that is composed of multiple materials, has a low center of gravity, reduced vibrations, and a greater moment of inertia.  
       SUMMARY OF INVENTION  
       [0019] The present invention provides a method for manufacturing a multiple material iron golf club head. The iron golf club head has a low center of gravity, a high moment of inertia, reduced vibrations and a solid feel and appearance.  
       [0020] One aspect of the present invention includes attaching a face plate to a periphery member to create a base assembly. Then, bonding a central member to the base assembly to create the finished iron golf club head.  
       [0021] 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 DRAWINGS  
     [0022]FIG. 1 is an exploded view of an iron club head.  
     [0023]FIG. 2 is a side exploded view of an iron club head.  
     [0024]FIG. 3 is a front plan view of the an iron club head.  
     [0025]FIG. 4 is a rear plan view of the iron club head of FIG. 1.  
     [0026]FIG. 5 is a toe side view of the iron club head of FIG. 1.  
     [0027]FIG. 6 is a heel side view of the iron club head of FIG. 1.  
     [0028]FIG. 7 is a top plan view of the iron club head of FIG. 1.  
     [0029]FIG. 8 is a bottom plan view of the iron club head of FIG. 1.  
     [0030]FIG. 9 is a flow chart of the main manufacturing process.  
     [0031]FIG. 9A is a continuation of the flow chart of FIG. 9  
     [0032]FIG. 10 is a flow chart of a periphery member formation process.  
     [0033]FIG. 11 is a flow chart of an alternative periphery member formation process.  
     [0034]FIG. 12 is a flow chart of a central member formation process.  
     [0035]FIG. 13 is a flow chart of an alternative central member formation process. 
    
    
     DETAILED DESCRIPTION  
     [0036] As shown in FIGS.  1 - 8 , an iron golf club head is generally designated  20 . The club head  20  is preferably composed of three main components: a periphery member  22 , a central member  24  and a face plate  26 . The club head  20  can range from a 1-iron to a lob-wedge, with the loft angle preferably ranging from fifteen degrees to sixty degrees. The three main components are assembled into the club head  20  using a process disclosed below.  
     [0037] The periphery member  22  is preferably composed of a material having a density greater than 7.86 grams per centimeter cubed (g/cm 3 ). A preferred material is an iron-nickel-tungsten alloy having a density preferably ranging from 8.0 g/cm 3  to 12.0 g/cm 3 , more preferably ranging from 10.0 g/cm 3  to 11.0 g/cm 3 , and most preferably 10.5 g/cm 3 . An alternative material is a stainless steel material. Those skilled in the pertinent art will recognize that other materials may be used for the periphery member  22  without departing from the scope and spirit of the present invention.  
     [0038] The periphery member  22  has sole wall  28 , a toe wall  30  extending upward from a toe end of the sole wall  28 , a heel wall  32  extending upward from the sole wall  28  near a heel end of the sole wall  28 , and a hosel  34  extending outward from the sole wall  28  at the heel end of the sole wall  28 . The hosel  34  is preferably offset. The hosel  34  has a bore  36  for receiving a shaft, and the upper end of the hosel  34  preferably lies below an upper end of the toe wall  30  when the club head  20  is in the address position for striking a golf ball, not shown. The bore  36  preferably extends through the entire hosel  34  providing a short straight hollow hosel such as disclosed in U.S. Pat. No. 4,995,609, which pertinent parts are hereby incorporated by reference.  
     [0039] The sole wall  28  preferably has a cambered exterior surface, which contacts the ground during a golf swing. As shown in FIG. 8, the sole wall  28  has a width, Ws, that preferably ranges from 1.00 inch to 1.75 inch, and is most preferably 1.25 inch. The sole wall  28  also has a length, Ls, from a toe end to the beginning of the bore  36 , which preferably ranges from 2.5 inches to 3.5 inches, and is most preferably 3.0 inches.  
     [0040] As shown in FIG. 5, the toe wall  30  preferably has a length, Lt, which preferably ranges from 1.5 inches to 2.5 inches, and is most preferably 2.0 inches. The toe wall  30  preferably has a width that tapers from a lower end to an upper end of the toe wall  30 .  
     [0041] As shown in FIG. 6, the heel wall  32  preferably has a length, Lh, which preferably ranges from 0.5 inch to 1.5 inches, and is most preferably 1.0 inch. The heel wall  32  preferably has a width that tapers from a lower end to an upper end of the heel wall  32 .  
     [0042] In general, the periphery member  22  provides the club head  20  with a greater moment of inertia due to its relatively large mass at the periphery of the club head  20 . Further, mass attributable to the sole wall  28  lowers the center of gravity of the club head  20  to promote a higher trajectory during ball striking. The periphery member  22  is preferably 15% to 50% of the volume of the club head  20  and preferably 50% to 80% of the mass of the club head  20 .  
     [0043] The central member  24  is composed of a non-metal material. Preferred materials include bulk molding compounds, sheet molding compounds, thermosetting materials and thermoplastic materials. A preferred bulk molding compound is a resinous material with reinforcement fibers. Such resins include polyesters, vinyl esters and epoxy. Such fibers include carbon fibers, fiberglass, aramid or combinations. A preferred sheet molding compound is similar to the bulk molding compounds, however, in a sheet form. A preferred thermoplastic material includes injection moldable materials integrated with fibers such as disclosed above. These thermoplastic materials include polyesters, polyethylenes, polyamides, polypropylenes, polyurethanes, and the like.  
     [0044] The central member  24  is primarily a support for the face plate  26 , and thus the central member should be able to withstand impact forces without failure. The central member  24  also reduces vibrations of the club head  20  during ball striking. The central member  24  is preferably 25% to 75% of the volume of the club head  20  and preferably 10% to 30% of the mass of the club head  20 .  
     [0045] The central member  24  preferably has a body portion  38 , a recess  40 , a forward surface  42 , a rear surface  43 , a sole surface  44 , a top surface  46 , a toe surface  48 , a heel surface  50  and a flange  52 . The forward surface  42  is preferably at an angle approximate that of the club head  20 . Thus, if the club head  20  is a 5-iron, then the forward surface preferably has an angle of approximately 27 degrees. The body portion  38  preferably tapers upward from the sole surface  44 .  
     [0046] The central member  24  is disposed on an interior surface of the sole wall  28  of the periphery member  22 . The toe surface  48  of the central member  24  preferably engages the interior surface of the toe wall  30  of the periphery member  22 . The heel surface  50  of the central member  24  preferably engages the heel wall  32  of the periphery member  22 . The top surface  46  preferably creates the top line of the club head  20 . The flange  52  extends from the top surface  46  outward over the forward surface  42  thereby creating a top cover for securing the face plate  26 . The face plate  26  is also secured within a ledge  60  of the periphery member  22 .  
     [0047] The face plate  26  is preferably composed of a light-weight material. Such materials include titanium materials, stainless steel, amorphous metals and the like. Such titanium materials include pure titanium and titanium alloys such as 6-4 titanium alloy, 6-22-22 titanium alloy, 4-2 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. The face plate  26  is preferably manufactured through casting, forging, forming, machining, powdered metal forming, metal-injection-molding, electrochemical milling, and the like.  
     [0048] The face plate  26  has an interior surface  56  which preferably engages the forward surface  42  of the central member  24 , and an exterior surface  54  which preferably has scorelines (not shown) thereon. The face plate preferably has a thickness that ranges from 0.04 inch to 0.250 inch, more preferably from 0.06 inch to 0.130 inch and most preferably 0.075 inch.  
     [0049] The club head  20  preferably has a total volume that ranges from 40.0 cm 3  to 60.0 cm 3 , more preferably from 45.0 cm 3  to 55.0 cm 3 , and most preferably 50.8 cm 3 . The club head  20  preferably has a mass that ranges from 240 grams to 270 grams, more preferably from 245 grams to 260 grams, and most preferably 253 grams.  
     [0050] The periphery member  22  preferably has a total volume that ranges from 10.0 cm 3  to 32.0 cm 3 , more preferably from 15.0 cm 3  to 20.0 cm 3 , and most preferably 18.8 cm 3 . The periphery member  22  preferably has a mass that ranges from 100 grams to 240 grams, more preferably from 150 grams to 200 grams, and most preferably 185 grams.  
     [0051] The central member  24  preferably has a total volume that ranges from 7.0 cm 3  to 35.0 cm 3 , more preferably from 15.0 cm 3  to 30.0 cm 3 , and most preferably 28.0 cm 3 . The central member  24  preferably has a mass that ranges from 9 grams to 70 grams, more preferably from 25 grams to 60 grams, and most preferably 45 grams.  
     [0052] The face plate  26  preferably has a total volume that ranges from 4.0 cm 3  to 8.0 cm 3 , more preferably from 4.5 cm 3  to 6.0 cm 3 , and most preferably 5.3 cm 3 . The face plate  26  preferably has a mass that ranges from 15 grams to 50 grams, more preferably from 20 grams to 30 grams, and most preferably 24 grams.  
     [0053] The center of gravity and the moment of inertia of a golf club head  20  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  20  may be obtained using a center of gravity table having two weight scales thereon, as disclosed in co-pending U.S. patent application Ser. No. 09/796,951, filed on Feb. 27, 2001, entitled High Moment Of Inertia Composite Golf Club, and hereby incorporated by reference in its entirety. If a shaft is present, it is removed and replaced with a hosel cube that has a multitude of faces normal to the axes of the golf club head. Given the weight of the golf club head, the scales allow one to determine the weight distribution of the golf club head when the golf club head is placed on both scales simultaneously and weighed along a particular direction, the X, Y or Z direction.  
     [0054] In general, the moment of inertia, Izz, about the Z axis for the golf club head  20  preferably ranges from 2200 g-cm 2  to 3000 g-cm 2 , more preferably from 2400 g- 2  to 2700 g-cm 2 , and most preferably from 2472 g-cm 2  to 2617 g-cm 2 . The moment of inertia, Iyy, about the Y axis for the golf club head  20  preferably ranges from 400 g-cm 2  to 700 g-cm 2 , more preferably from 500 g-cm 2  to 600 g-cm 2 , and most preferably from 530 g-cm 2  to 560 g-cm 2 . The moment of inertia, Ixx, about the X axis for the golf club head  20  preferably ranges from 2450 g-cm 2  to 3200 g-cm 2 , more preferably from 2500 g-cm 2  to 2900 g-cm 2 , and most preferably from 2650 g-cm 2  to 2870 g-cm 2 .  
     [0055] For comparison, the new BIG BERTHA® 5-iron from Callaway Golf Company has a moment of inertia, Izz, of 2158 g-cm 2 , a moment of inertia, Iyy, of 585 g-cm 2 , and a moment of inertia, Ixx, of 2407 g-cm 2 .  
     [0056] In manufacturing the iron golf club head  20 , the three main components are preferably prepared first, and then assembled into the club head  20 . The face plate  26  is preferably stamped or hot-formed. Scorelines are preferably created with the forming process, however, the scorelines may alternatively may machined in after the forming process. The fabrication processes of the periphery member and central member are set forth in the flow charts of FIGS.  10 - 13 . The main assembly process  100  is set forth in FIGS. 9 and 9A.  
     [0057] The process  100  commences with forming the periphery member  22  at box  102  and forming the face plate  26  at box  104 . Next, at box  106  the face plate  26  is assembled with the periphery member  22  to form a base assembly. Three preferred options for assembly include swaging, brazing and bonding.  
     [0058] At box  106   a , the face plate  26  is swaged into the periphery member  22 . This option includes deforming the face plate  26  to fit and roll the face plate  26  over the edges of the periphery member  22 , or using a brass locking ring to fit and lock the face plate  26  to the periphery member  22 . At alternative box  106   b , the face plate  26  is positioned in the periphery member  22 , and then brazed with a titanium nitride foil or paste. At alternative box  106   c , an adhesive such as an epoxy, is applied to the contact surfaces of the face plate  26  and the periphery member  22 , and then the face plate  26  is bonded to the periphery member  22 . Next, at boxes  108  or  108   a , the base assembly is inspected to ensure proper attachment of the face plate  26  to the periphery member  22 . At box  110  the base assembly is prepared for the next assembly through polishing and/or grinding.  
     [0059] At box  112  the central member  24  is prepared and received for assembly. At box  114  an adhesive such as DP810 acrylate or DP420 epoxy adhesives, both from 3M Company, are applied to the central member  24  and the base assembly. Next, at box  116 , the central member  24  is bonded to the base assembly of the face plate  26  and the periphery member  22  to create a final assembly. At box  118 , the final assembly is inspected and at box  120  the iron golf club head  20  is finished.  
     [0060]FIG. 10 illustrates a preferred process  102  for forming the periphery member  22 . At box  130 , a cast mold is heated. At box  132 , a heavy metal alloy is melted to pour into the mold. At box  134 , the alloy is poured into the mold and the periphery member precursor is cast. At box  136  the ceramic mold is removed. At box  138 , the gates are removed from the periphery member precursor. At box  140 , the periphery member  22  is ground and polished. At box  142 , the periphery member is inspected. At box  144 , the periphery member  22  is prepared for assembly.  
     [0061]FIG. 11 illustrates an alternative process for forming the periphery member through use of metal injection molding, powdered metal formation or liquid infiltration. At box  150 , the alloys mixed, and in a specific preferred example tungsten iron and nickel are mixed. At box  152  the density of the alloy is measured. At box  154 , the periphery member precursor is compression molded or injection molded. At box  156  this precursor is inspected. At box  158 , the periphery member precursor is sintered for metal injection molding or with liquid infiltration the precursor is infiltrated with a liquid metal. At box  160 , the periphery member is vacuum resin infused if a powder metal formation process is used in order to reduce porosity. Box  160  is not preferably used for metal injection molding or liquid infiltration. At box  162  the periphery member precursor is ground and/or polished. At box  164 , the periphery member is inspected and at box  166  is the periphery member  22  is prepared for assembly.  
     [0062]FIG. 12 is a flow chart of a preferred formation process for the central member  24 . At box  170 , the materials for the central member  24  are received, and these materials can include bulk molding compounds, sheet molding compounds, thermosetting materials and thermoplastic materials as discussed above. At box  172 , the material is weighed and a preform of the central member is created from the material. At box  174 , the preform is compression transfer molded at approximately 300 degrees Celsius for approximately five minutes. At box  176 , this molded preform is inspected. At box  178 , the preform is prepared and masked for blasting. At box  180 , the central member precursor is blasted to remove excess materials. At box  182 , the central member  22  is inspected and at box  184  it is prepared for assembly.  
     [0063]FIG. 13 is a flow chart of an alternative formation process for the central member  24 . At box  190 , the materials for the central member  24  are received, and these materials can include thermosetting materials and thermoplastic materials as discussed above. At box  192 , the materials are loaded into the hopper. At box  194 , the materials are injection molded into a central member precursor. At box  195 , this precursor is inspected. At box  196 , the precursor is prepared and masked for blasting. At box  197 , the central member precursor is blasted to remove excess materials. At box  198 , the central member  24  is prepared for assembly.  
     [0064] 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.