Abstract:
An improved core for creating wax patterns of golf club heads is disclosed herein. The core includes a center core piece and several outer core pieces removably coupled to the center core piece by magnets embedded in each of the core pieces. The core further includes a pneumatic release system, including a manifold, to easily separate the center core piece from the outer core pieces and expel the center core piece from a wax pattern, thereby eliminating the need to pry and pull pieces out with a tool, which could damage the wax pattern of the golf club head.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS  
       [0001]     The Present Application is a divisional Application of U.S. patent application Ser. No. 10/248,072, filed Dec. 16, 2002, which claims priority to U.S. Provisional Patent Application NO. 60/343,982 filed on Dec. 26, 2001 
     
    
     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 investment cast molding tools for the manufacture of golf club heads. More specifically, the present invention relates to an investment cast molding apparatus for the construction of metal wood-type golf club heads.  
         [0005]     2. Description of the Related Art  
         [0006]     One of the oldest methods of forming golf club heads is through investment casting. This process is currently used to produce the majority of wood-type golf club heads. In this process, a resin mold, which includes two plates composed of aluminum hinged at one end and having a hollow center, is used. A master copy of the golf club head to be produced is suspended in the hollow center and a liquid resin is poured around the master copy to create the outer shape of the golf club head upon solidification of the resin.  
         [0007]     In hollow metal wood-type golf club heads, the interior shape of the golf club head is produced by an aluminum core, which typically consists of five pieces. Wax is injected into the mold to fill the space between the inner and outer shapes of the golf club head. The mold is opened and the aluminum core with the wax pattern around it is removed. The aluminum core is separated from the wax pattern by first removing a center piece of the core. The remaining pieces of the core may then be shifted around and removed through the opening that was created by removal of the center core piece. When all of the pieces of the core have been removed, the wax pattern of the golf club head will have a large hole in the either crown or sole, through which the aluminum core was removed. This hole will be covered by a plate, which is typically welded about its perimeter to the golf club head. The weld is then sanded smooth to blend with the rest of the golf club head.  
         [0008]     There are several areas with this apparatus and manufacturing process that could be improved. First, the removal of the core from the wax pattern and mold can be time-consuming and laborious. Typically, a tool is inserted into openings formed in the base of the core and used to pry the individual core pieces from the wax pattern and mold. The tool may slip and can damage the core, wax pattern and/or the mold. Second, extraction of the first core piece from the mold can create a suction force on the wax pattern, drawing the wax pattern away from the mold and damaging it. Third, the individual core pieces, which are designed to slide in a longitudinal direction with respect to each other so as to enable their removal from the wax pattern, lack a means for restricting movement in the longitudinal direction during insertion of the core into the cavity of the mold. Thus, as the core is being placed in the mold cavity, individual core pieces can slide relative to the others and damage either themselves or the mold.  
         [0009]     Thus, there is a need for an improved aluminum core that stays together during insertion of the core in a mold and is easy to remove from a wax mold.  
       BRIEF SUMMARY OF THE INVENTION  
       [0010]     The present invention is an improved core for producing hollow wax patterns of golf club heads. The improved core includes a center core piece and a plurality of outer core pieces. Each of the outer core pieces is removably coupled to a respective side wall of the center core piece. Magnets embedded in each of the core pieces secure the various core pieces together. The improved core further includes a pneumatic release system to easily separate the center core piece from the outer core pieces and expel the center core piece from the wax mold. The pneumatic release system eliminates the need to pry and pull pieces out with a tool, which could damage the wax pattern of the golf club head.  
         [0011]     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  
       [0012]      FIG. 1  is a top plan view of an apparatus and a core for forming a golf club head in accordance with the present invention.  
         [0013]      FIG. 2  is a front plan view of the core shown in  FIG. 1 .  
         [0014]      FIG. 3  is a top plan view of the core of  FIG. 2 .  
         [0015]      FIG. 4  is a partial exploded perspective view of the core of  FIG. 2 .  
         [0016]      FIG. 5  is a top plan view of the manifold of the core of  FIG. 2 .  
         [0017]      FIG. 6  illustrates a center piece of the core of  FIG. 2  being expelled from a wax pattern.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]     The present invention is directed to an apparatus and a method for producing hollow wax patterns of golf club heads, and more particularly a hollow metallic wood-type golf club head. The improved core of the present invention has magnets embedded in each of the core pieces to secure the individual core pieces together. The core further includes a pneumatic release system for separating the center core piece from the outer core pieces and expelling the center core piece from a wax mold, without the use of a prying tool and without damage to the wax pattern.  
         [0019]      FIG. 1  illustrates an apparatus  10  for forming a golf club head in accordance with the present invention. Apparatus  10  includes a first half  12  and a second half  14 , which are coupled together by a hinge  16 . First and second halves  12  and  14  make up a mold  18  that has a mold cavity  20 , one portion  20   a  of which is formed in first half  12 , and another portion  22   b  of which is formed in second half  14 . When the two halves  12  and  14  of apparatus  10  are brought together in a closed position, portions  20   a  and  20   b  register together to form a single, complete mold cavity  20 .  
         [0020]     Mold cavity  20  has a shape generally complementary to the exterior of the desired golf club head, with cavity portion  20   a  forming a majority of the club head exterior, and cavity portion  20   b  forming the a front portion of the club head. Apparatus  10  includes a telescoping insert pin  22  for forming the space in the golf club head that will later be occupied by a golf club shaft.  
         [0021]     Mold cavity  20  is designed to receive a core  30 . As will be described in greater detail below, core  30  is comprised of multiple of core pieces. Core  30  has an upper portion  32  that is generally identical in size and shape to an interior of the golf club head. Core  30  further includes a lower portion  34  that extends from mold cavity  20  of apparatus  10 , when core  30  is placed in mold  18 .  
         [0022]     Apparatus  10  further includes a supply duct  24  for directing injected wax into mold cavity  20  and around core  30 . In addition, apparatus  10  includes a spring lock  26  mounted on second half  14 . Spring lock  26  includes a retractable locking pin  28  that engages an aperture in core  30  to firmly fix the core  30  in mold cavity  20 . Additional information about wax molding methods and articles for manufacturing golf club heads is disclosed in U.S. Pat. Nos. 5,547,360, 5,577,550, 5,204,046, 5,669,828 and 5,417,559, all of which are hereby incorporated by reference in their entirety.  
         [0023]      FIGS. 2-4  illustrate core  30  in greater detail. Core  30  is preferably made of a metal, such as aluminum. Core  30  includes a center core piece  36  and outer core pieces  38   a - 38   e . Each outer core piece  38   a - 38   e  has a planar surface that is flush with a respective planar side wall  40   a - 40   e  of center core piece  36 . Although five outer core pieces  38   a - 38   e  are depicted in the drawings, one of ordinary skill in the art will appreciate that core  30  may have fewer than or greater than five outer core pieces as well.  
         [0024]     Center core piece  36  includes a base  42  and a manifold  44 . Base  42  has a generally planar upper surface  46 , from which side walls  40   a - 40   e  extend upward to a top surface  48  of center core piece  36 . Top surface  48  of center core piece  36  forms a portion of an interior wall of the golf club head. Pins  50  project from upper surface  46  of base  42  and are received in respective openings (not shown) formed in outer core pieces  38   a - 38   e . Pins  50  align outer core pieces  38   a - 38   e  with respect to center core piece  36  and restrict the movement of outer core pieces  38   a - 38   e  relative to center core piece  36  to a single direction.  
         [0025]     Center core piece  36  further includes a magnet  50  embedded in each side wall  40   a - 40   e  thereof. Magnets  50  are preferably located proximate top surface  48  of center core piece  36 , however, one of ordinary skill in the art will appreciate that magnets  50  may be located at other suitable locations along side walls  40   a - 40   e . Each side wall  40   a - 40   e  may further include more than one magnet  50 . A magnet  52  is embedded in the planar surface of each outer core piece  38   a - 38   e  at a corresponding location. Magnets  50  and  52  removably secure outer core pieces  38   a - 38   e  to center core piece  36 . Each magnet  50  is flush with a respective side wall  40   a - 40   e  of center core piece  36 . Similarly, each magnet  52  is flush with the planar surface of the outer core piece  38   a - 38   e . Thus, outer core pieces  38   a - 38   e  may be slid along the respective side wall  40   a - 40   e  of center core piece  36  without any interference from magnets  50  and  52 . Magnets  50  and  52  prevent unwanted movement of outer core pieces  38   a - 38   e  with respect to center core piece  36 , such as during insertion of core  30  into cavity  20  of apparatus  10 . Without magnets  50  and  52 , outer core pieces  38   a - 38   e  may separate from center core piece  36  and damage either themselves or mold  18 .  
         [0026]     One side wall  40   a  of center core piece  36  has an opening  54  formed therein. Opening  54  is located near top surface  48  of center core piece  36 . Opening  54  leads to a passage  56  that extends through base  42  and manifold  44  of center core piece  36 . Passage  54  and opening  56  are part of the pneumatic release system for expelling center core piece  36  from a wax pattern.  
         [0027]     Manifold  44 , which is attached to base  42  of center core piece  36 , completes the pneumatic release system. Manifold  44  has an opening  58  that is aligned with passage  54  in base  42 . As illustrated in  FIG. 5 , manifold  44  further includes a groove  60  formed in an upper surface  62  of manifold  44 . Groove  60  connects a chamber  64  formed in each of the outer core pieces  38   a - 38   e , through additional openings  59  formed in base  42 , to a vent hole  66 .  
         [0028]     Manifold  44  also helps to position and align core  30  in mold cavity  20 . Manifold  44  includes an aperture  68  for receiving retractable locking pin  28  of spring lock  26  to secure core  30  in mold cavity  20 . Thus, when core  30  is placed in mold cavity portion  20   a  and apparatus  10  is closed, the locking pin  28  of spring lock  26  engages aperture  68  in manifold  44  to positively lock core  30  in place ( FIG. 5 ).  
         [0029]     With core  30  secured in mold cavity  20  of apparatus  10 , wax is introduced to supply duct  24  and injected into mold cavity  20 . The wax encases top portion  32  of core  30  and forms a wax pattern  70  of a hollow golf club head.  FIG. 6  illustrates wax pattern  70  formed about top portion  32  of core  30 . When wax pattern  70  has cooled, it may then be removed from apparatus  10 . To remove wax pattern  70 , apparatus  10  is opened, and pin  28  of spring lock  26  on second half  14  of apparatus  10  is retracted from aperture  68  in manifold  44 , thereby releasing core  30  from its fixed position in apparatus  10 .  
         [0030]     A source  72  of pressurized gas, such as compressed air, is then supplied to opening  58  in manifold  44  of core  30 . The pressurized gas travels through passage  56  in center core piece  36  and out opening  54  in side wall  40   a . The pressurized gas travels upward, compressing between wax pattern  70  and top surface  48  of center core piece  36 . This compressive force is sufficient to overcome the magnetic forces holding center core piece  36  and outer core pieces  38   a - 38   e  together, and center core piece  36  is pushed out of wax pattern  70  and mold cavity  20 . Pressurized gas also enters chambers  64  in outer core pieces  38   a - 38   e  to maintain outer core pieces  38   a - 38   e  in wax pattern  70  as center core piece  36  is expelled. Excess gas and any vacuum or suction created by expulsion of the center core piece  36  is released through vent hole  66 , making the removal of center core piece  36  easy.  
         [0031]     After center core piece  36  has been expelled, outer core pieces  38   a - 38   e  may be individually removed through the opening in wax pattern  70  created by center core piece  36  and directly reassembled onto center core piece  36 , so that core  30  is ready for use.  
         [0032]     The unencumbered wax pattern  70  may then be removed from mold cavity  20  of apparatus  20 . A golf club head is then formed as discussed in U.S. Pat. No. 5,577,550. The club head is typically formed of titanium, steel, titanium alloys, steel alloys, amorphous metals and the like, and can vary in size from 150 cc to 500 cc, more preferably 250 cc to 385 cc, and most preferably 335 cc.  
         [0033]     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.