Patent Publication Number: US-6220971-B1

Title: Golf club and method of manufacturing same

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a golf club and a method of manufacturing the same. 
     In the prior art, Japanese Patent No. 2602253, by the same applicant, describes a golfing iron club head formed by fixing a plurality of members while subjecting them to plastic deformation. This golfing iron club head comprises, as shown for example in FIG. 1 of the above publication, a face member, a weight member provided on a rear surface of the face member, a first cavity portion formed in a rear surface of the face member with a peripheral face in a reverse tapered shape, a second cavity portion formed in a front surface of the weight member opposite to the first cavity portion with a peripheral face in a reverse tapered shape, and a connecting member such as an adhesive or carbon fiber filled and solidified between the first cavity portion and the second cavity portion. In this manner, the face member and the weight member may comprise different materials but are integrally and securely connected to one another. 
     Also, in the prior art, for such heads, materials having relatively low proof stress and which are easily plastically deformed, such as pure titanium, iron, stainless steel, copper and the like have been used. To obtain higher performance however, the adoption of high-strength materials such as titanium alloy, amorphous alloy and marageing steel has recently been studied. These high-strength materials have a problem in that they are not easily plastically deformed because they have high proof stress and large spring back, and are susceptible to deformation. As a result, in the case of members using high-strength materials, there are problems in that the connection strength is weak, and there is a gap between both members, which is undesirable from an appearance point of view. Specifically, in the case where a face member is fitted to a head body having a window opening as described in Japanese Patent No. 2560272, there is a problem in that the edge of the window opening tends to be bent back at the time of pressing. 
     One means for solving these problems is adhesion. However, adhesion is not sufficiently strong. Moreover, the method used with the golf club head disclosed in Japanese Patent No. 2560272 by the same applicant is also known. This golf club head as shown in FIG. 1 of the above publication, is one which is provided with a face on a front surface and a shaft connecting portion on one side, and comprises a head body formed with a sole, a cavity portion corresponding to the face formed in the front surface, a through hole formed in the cavity portion and directed rearward and a face member formed from a plate-like metallic material having a lower specific gravity than the head body and fitted into the cavity portion. The cavity portion is formed in a reverse tapered shape, and the face member is pressed into the cavity portion using a press, so that the face member is secured to the cavity portion. Furthermore, Japanese Unexamined Patent Publication No. Hei 9-276453 by the same applicant discloses a manufacturing method for a golf club head comprising a head body having a face, and a weight secured to a rear side of the head body, wherein there is formed a plurality of threaded holes respectively facing the head body and the weight, and the weight is secured while plastically deforming opposite ends of a fixing member in the facing threaded holes. 
     Utilizing the fixing means disclosed in the above-mentioned Japanese Patent No. 2605253 and Japanese Unexamined Patent Publication No. Hei 9-276453 has been considered. However, it is not possible to secure the face member as described in these publications to a head body having a window opening as in the above-mentioned Japanese Patent No. 2560272. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to be able to reliably secure together each member in a golf club head formed from a plurality of members. 
     According to a first embodiment of the present invention there is provided a golf club with a head provided with a face on a front surface and a shaft connecting portion on one side, and a shaft connected to the shaft connecting portion. The head, which is formed by integrally connecting a plurality of members, is provided with connection recesses in portions where the plurality of members face each other. At least one of the connection recesses is formed in a reverse tapered shape. A fixing member is arranged between facing connection recesses, and the fixing member is plastically deformed so as to be pressed into the connection recesses, to thereby secure the facing members together. 
     In the first embodiment, by attaching the connecting member between the connection recesses by pressing thereinto, facing members of the head can be reliably secured to each other. 
     According to a second embodiment of the present invention, there is provided a golf club with a head provided with a face on a front surface and a shaft connecting portion on one side, and a shaft connected to the shaft connecting portion, the head, which is formed by integrally connecting a plurality of members, is provided with connection recesses in portions where the plurality of members face each other. Irregularities are formed on a peripheral face of at least one of the connection recesses. A fixing member is arranged between facing connection recesses, and the fixing member is plastically deformed so as to be pressed into the connection recesses, to thereby secure the facing members. 
     In the second embodiment, by attaching the connecting member between the connection recesses by pressing thereinto, facing members of the head can be reliably secured to each other. 
     According to a third embodiment of the present invention, there is provided a golfing iron club with a head provided with a face on a front surface and a shaft connecting portion on one side, and a shaft connected to the shaft connecting portion, the head comprising a head body formed with a sole, a cavity portion corresponding to the face formed in a front surface, a window opening formed inside the cavity portion and passing through to a rear surface side and a face member formed from a plate-like metallic material and fitted into the cavity portion. Further, a first connection recess is formed in the cavity portion, a second connection recess is formed in a portion of the face member facing the first connection recess, and a fixing member is arranged between the first and the second connection recesses, and the fixing member is plastically deformed so as to be pressed into the first and the second connection recesses, to thereby secure the face member to the head body. 
     In the third embodiment, the face member can be fitted into the cavity portion on the head body, and a desired location in the cavity portion and a desired location in the face member can be reliably secured together. 
     According to a fourth embodiment of the present invention, there is provided a method of manufacturing a golfing iron club with a head provided with a face on a front surface and a shaft connecting portion on one side, and a shaft connected to the shaft connecting portion, the head comprising a head body formed with a sole, a cavity portion corresponding to the face formed in a front surface, a window opening formed inside the cavity portion and passing through to a rear surface side and a face member formed from a plate-like metallic material and fitted into the cavity portion. Further, a first connection recess is formed in the cavity portion, a second connection recess is formed in a portion of the face member facing the first connection recess, and the face member is pressed into the cavity portion, and at the time of the pressing, a fixing billet is arranged between the first and the second connection recesses and the fixing billet is plastically deformed so as to be pressed into the first and the second connection recesses, to thereby secure the face member to the head body. 
     In the fourth embodiment, the fixing billet is plastically deformed at the time of pressingly inserting the face member, so as to be fitted into the first and the second connection recesses. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects, features and advantages of the invention will become apparent to those skilled in the art, from the following description of the preferred embodiments of the invention, wherein reference is made to the accompanying drawings, in which: 
     FIG. 1A is a cross-sectional view of a first embodiment of the present invention, while 
     FIG. 1B is a partially enlarged cross-sectional view thereof; 
     FIG. 2 is an exploded perspective view of the first embodiment of the present invention; 
     FIG. 3 is a cross-sectional view at the time of manufacturing, illustrating the first embodiment of the present invention; 
     FIG. 4A is a cross-sectional view of a second embodiment of the present invention, while 
     FIG. 4B is a partially enlarged cross-sectional view thereof; 
     FIG. 5 is an exploded perspective view of the second embodiment of the present invention; and 
     FIG. 6 is a cross-sectional view at the time of manufacturing, illustrating the second embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION 
     A description of embodiments of the present invention is set forth below with reference to the appended drawings. As shown in FIG.  1  through FIG. 3, a golf club comprises a head  1  and a shaft  2 . The head  1  is provided on a front surface with a face  3  for striking a golf ball, and on one side with a shaft connecting portion  4  for connecting the shaft  2 . The head  1  comprises: a head body  7  being a first constituent member of the head  1 , which is made of stainless steel such as SUS  304 , and which is formed with a cavity portion  5  corresponding to the face  3 , and a window opening  6  in the cavity portion  5  opening toward the rear, and which is provided with the shaft connecting portion  4  on one side; and a face member  8  being a plate-like second constituent member of the head  1 , set into the cavity portion  5  and made of a high-strength metal such as a titanium alloy containing 15% of vanadium, 3% of aluminum, 3% of tin, and 3% of chromium, being a so-called 15.3.3.3 β-titanium alloy type, or the like. A peripheral face  9  of the cavity portion  5  is formed in a reverse tapered shape, expanding rearward, and a peripheral face  10  of the face member  8  is formed slightly larger than the peripheral face  9 . By pressing the face member  8  into the cavity portion  5 , plastic deformation is caused between the face member  8  and the cavity portion  5 , to thereby secure the two members together. Moreover, a bottom portion  6 A on a side of the cavity portion  5  including a sole  11  (hereinafter referred to as the sole side) is deeply gouged and formed in a so-called “under cut” shape. Therefore, on the front part of the bottom portion  6 A is formed, as well as a protrusion  6 B provided in a protruding condition on a rear surface  16  of the face member  8 . In addition, in the figures, numeral  12  denotes a heel, and  13  denotes a toe, and the longitudinal width of the cavity portion  5  is formed gradually expanding from the heel  12  toward the toe  13 . 
     Moreover, in the sole side of a rear surface  14  of the cavity portion  5 , that is, in the front surface of the protrusion  6 B, there is formed a first connection recess  15 . Furthermore, in a portion on the rear surface  16  of the face member  8  opposite to the first connection recess  15  there is formed a second connection recess  17 . The first connection recess  15  has a lateral width of an opening  15 A of not larger than 20 mm, preferably about 10 mm, and a longitudinal width of about 10 mm, preferably about 5 mm, and a peripheral face  15 B in the section is formed in a reverse tapered shape so that the longitudinal width and/or the lateral width gradually expands rearward. Likewise, the second connection recess  17  has a lateral width of an opening  17 A of not larger than 20 mm, preferably about 10 mm, and a longitudinal width of about 10 mm, preferably about 5 mm, and a peripheral face  17 B in the section is formed in a reverse tapered shape so that the longitudinal width and/or the lateral width gradually expands forward. Between the first and the second connection recesses  15  and  17 , there is fitted a fixing member  18  made of a material such as copper which easily undergoes plastic forming, that is, which has a smaller longitudinal elastic modulus or Young&#39;s modulus than that of the head body  7  or the face member  8 . Fitting of the fixing member  18  is performed by arranging a cylindrical shaped fixing billet  18 A between the first connection recess  15  and the second connection recess  17 , and subjecting the fixing billet  18 A to plastic deformation at the time of pressing the face member  8  into the cavity portion  5 , so as to be pressed into both the first and the second connection recesses  15  and  17  in a reverse tapered shape. The fixing billet  18 A is sized so as to be able to be respectively inserted into the openings  15 A and  17 A of the first and second connection recesses  15  and  17 , and so that the volume thereof is substantially the same as or slightly smaller than the volume of the first and second connection recesses  15  and  17 . 
     Next is a description of the manufacturing method, with particular reference being made to FIG.  3 . The head body  7  is set in a lower die  19  which is one die, and the fixing billet  18 A is set in the first connection recess  15 . Then the face member  8  is set so that the face member  8  faces the cavity portion  5  and the second connection recess  17  faces the fixing billet  18 A. When the face member  8  is pressed by a press apparatus using an upper die  20  which is the other die, the peripheral face  10  is pressed in along the peripheral face  9 , while being plastically deformed, and the peripheral face  10  is formed into a reverse tapered shape. At the same time, the fixing billet  18 A is plastically deformed along the first and second connection recesses  15  and  17 , with peripheral faces  18 B on both sides being pressed into reverse tapered shapes sharing the rear surface  14  of the cavity portion  5  as a border. 
     As a result, the peripheral face  10  is plastically deformed and pressed in alone, the peripheral face  9  in a reverse tapered shape by pressing so that the face member  8  is secured to the cavity portion  5  with the reverse tapered shape. At the same time, the peripheral faces  18 B of the fixing billet  18 A are pressed while being plastically deformed along the first and second connection recesses  15  and  17  into reverse tapered shapes. As a result, the sole side of the rear surface  14  of the cavity portion  5  and the lower part of the rear surface  16  of the face member  8  can be tightly secured together. Thus, by securing together with the fixing member  18 , the sole side of the rear surface  14  and the protrusion  6 B formed adjacent the lower part of the rear surface  16  of the face member  8 , then the bending back of the protrusion  6 B located on the front part of the under-cut window opening  6  can be prevented. 
     With the embodiment as described above, with the golf club with the head  1  provided with the face  3  on the front surface and the shaft connecting portion  4  on one side, and the shaft  2  connected to the shaft connecting portion  4 , the head  1  which is formed by integrally connecting the head body  7  being the first constituent member of the head  1 , and the face member  8  being the second constituent member of the head  1 , is provided with reverse tapered shape connection recesses  15  and  17  in respective portions where the head body  7  and the face member  8  face each other. That is, connection recesses  15  and  17  are situated in the protrusion  6 B and in the rear surface  16  of the face member  8 . The fixing member  18  is arranged between the facing connection recesses  15  and  17 , and the fixing member  18  is plastically deformed so as to be pressed into the connection recesses  15  and  17 , to thereby secure the head body  7  to the face member  8 . Hence, the face member  8  comprising a high-strength material can be reliably secured to the head body  7 . 
     Moreover, the head  1  comprises: the head body  7  formed with the sole  11 , the cavity portion  5  corresponding to the face  3  formed in the front surface, the window opening  6  formed inside the cavity portion  5  and passing through to the rear surface side and the face member  8  formed from the plate-like metallic material and fitted into the cavity portion  5 , and the first connection recess  15  is formed in the cavity portion  5 , the second connection recess  17  is formed in the portion of the face member  9  facing the first connection recess  15 . The fixing member  18  is arranged between the first and second connection recesses  15  and  17 , and the fixing member  18  is plastically deformed so as to be pressed into the first and the second connection recesses  15  and  17 , to thereby secure the face member  8  to the head body  7 . Hence, the face member  8  comprising a high-strength material can be reliably secured to the head body  7 . Moreover, by forming the first connection recess  15  in the protrusion  6 B located on the front part of the window opening  6 , the protrusion  6 B will not be bent back, even if the window opening  6  is “under-cut”. As a result, the face member  8  and the head body  7  can be reliably secured together. 
     Furthermore, the head  1  comprises the head body  7  formed with the sole  11 , the cavity portion  5  corresponding to the face  3  formed in the front surface, the window opening  6  formed inside the cavity portion  5  and passing through to the rear surface side and the face member  8  formed from the plate-like metallic material and fitted into the cavity portion  5 , and the first connection recess  15  is formed in the cavity portion  5 , the second connection recess  17  is formed in the portion of the face member  8  facing the first connection recess  15 , and the face member  8  is pressed into the cavity portion  5 . At the time of the pressing, the fixing billet  18 A is arranged between the first and second connection recesses  15  and  17  and the fixing billet  18 A is plastically deformed so as to be pressed into the first and second connection recesses  15  and  17 , to thereby secure the face member  8  to the head body  7 . As a result, by a single press operation, the peripheral face  10  of the face member  8  can be secured to the peripheral face  9  of the cavity portion  5 , and the bottom face  14  of the cavity portion  5  and the rear surface  16  of the face member  8  can be reliably secured together by the fixing member  18 . 
     With reference to FIGS. 4-6, a second embodiment of the present invention will be described. Components corresponding to the components of the first embodiment are denoted by the same symbols, and the details thereof are omitted. With the second embodiment, first connection recesses  21  are provided in left and right sides of a bottom portion of a rear surface  14  of a cavity portion  5 , and second connection recesses  22  are provided in portions on a rear surface  16  of a face member  8  opposite to the first connection recesses  21 . The first and second connection recesses  21  and  22  are respectively formed with irregularities on their peripheral faces  21 A and  22 A. Specifically, the first and second connection recesses  21  and  22  are formed with a female threads. A peripheral face  23 B of a fixing member  23  provided between the first and second connection recesses  21  and  22  is pressed into the irregularities formed alone, the peripheral faces  21 A and  22 A. 
     Next is a description of the manufacturing method, with particular reference being made to FIG. 6. A head body  7  is set in a lower die  19  which is one die, and fixing billets  23 A are set in the first connection recesses  21 . The fixing billets  23 A are round bar shape as with the first embodiment or male threaded rods, and opposite ends thereof are formed in a size which can be inserted into the openings  21 B and  22 B of the first and second connection recesses  21  and  22 . The face member  8  is then set so that the face member  8  faces the cavity portion  5  and the second connection recesses  22  face the fixing billets  23 A. When the face member  8  is pressed by a press apparatus using an upper die  20  which is the other die, a peripheral face  10  is pressed in along a peripheral face  9 , while being plastically deformed, and the peripheral face  10  is formed into a reverse tapered shape. At the same time, the fixing billets  23 A are plastically deformed alone, the first and second connection recesses  15  and  17  so that respective irregular shapes are formed on the peripheral faces on both sides, sharing the rear surface  14  of the cavity portion  5  as a border. 
     With the embodiment as described above, with the golf club with a head  1  provided with a face  3  on the front surface and the shaft connecting portion  4  on one side, and the shaft  2  connected to the shaft connecting portion  4 , the head  1  which is formed by integrally connecting the head body  7  and the face member  8 , is provided with the first connection recesses  21  on the head body  7 , and the second connection recesses  22  on the face member  8 , and irregularities are formed on the peripheral faces  21 A and  22 A of the first and second connection recesses  21  and  22 . The fixing members  23  are arranged between the facing connection recesses  15  and  17 , and the fixing members  23  are plastically deformed so as to be pressed into the first and second connection recesses  21  and  22 , to thereby secure the head body  7  and the face member  8  together. Hence, the face member  8  comprising a high-strength material can be reliably secured to the head body  7 . 
     Furthermore, the head  1  comprises the head body  7  formed with a sole  11 , the cavity portion  5  corresponding to the face  3  formed in a front surface, a window opening  6  formed inside the cavity portion  5  and passing through to a rear surface side and the face member  8  formed from a plate-like metallic material and fitted into the cavity portion  5 , and the first connection recesses  21  are formed in the cavity portion  5 , the second connection recesses  22  are formed in portions of the face member  8  facing the first connection recesses  21 . Further, the fixing members  23  are arranged between the first and the second connection recesses  21  and  22 , and the fixing members  23  are plastically deformed so as to be pressed into the first and the second connection recesses  21  and  22 , to thereby secure the face member  8  to the head body  7 . As a result, the face member  8  comprising a high-strength material can be reliably secured to the head body  7 . Moreover, by forming the first connection recesses  21  in the protrusion  6 B located on the front part of the window openine,  6 , the protrusion  6 B will not be bent back, even if the window opening  6  is “under-cut”. Hence, the face member  8  and the head body  7  can be reliably secured together. 
     Furthermore, the head  1  comprises the head body  7  formed with the sole  11 , the cavity portion  5  corresponding to the face  3  formed in the front surface, the window opening  6  formed inside the cavity portion  5  and passing through to the rear surface side and the face member  8  formed from a plate-like metallic material and fitted into the cavity portion  5 , and the first connection recesses  21  are formed in the cavity portion  5 , the second connection recesses  22  are formed in the portions of the face member  8  facing the first connection recesses  21 , and the face member  8  is pressed into the cavity portion  5 . At the time of the pressing, the fixing billets  23 A are arranged between the first and second connection recesses  21  and  22  and the fixing billets  23 A are plastically deformed so as to be pressed into the first and second connection recesses  21  and  22 , to thereby secure the face member  8  to the head body  7 . As a result, by a single press operation, the peripheral face  10  of the face member  8  can be secured to the peripheral face  9 ,of the cavity portion  5  and the bottom face  14  of the cavity portion  5  and the rear surface  16  of the face member  8  can be reliably secured together by the fixing member  23 . 
     The present invention is not limited to the above-described embodiments, but also encompasses various modifications within the scope of the present invention. For example with the first embodiment, either one of the first and second connection recesses  15  and  17  may be formed in a reverse tapered shape, and with the second embodiment, either one of the first and second connection recesses  21  and  22  may be formed with irregularities. Moreover, with the first embodiment the first and second connection recesses  15  and  17  are formed in one place. However, these may be formed in a plurality of places. 
     According to the first embodiment of the present invention, there is provided there is provided a golf club with a head provided with a face on a front surface and a shaft connecting portion on one side, and a shaft connected to the shaft connecting portion, the head which is formed by integrally connecting a plurality of members, is provided with connection recesses in portions where the plurality of members face each other, at least one of the connection recesses being formed in a reverse tapered shape. Further, the golf club includes a fixing member arranged between facing connection recesses, and the fixing member is plastically deformed so as to be pressed into the connection recesses, to thereby secure the facing members together. By attaching the connecting member between the connection recesses by pressing thereinto, facing members of the head which comprise different materials can be reliably secured to each other. 
     According to the second embodiment of the present invention, there is provided a golf club with a head provided with a face on a front surface and a shaft connecting portion on one side, and a shaft connected to the shaft connecting portion, the head which is formed by integrally connecting a plurality of members, is provided with connection recesses in portions where the plurality of members face each other, and irregularities are formed on a peripheral face of at least one of the connection recesses. A fixing member is arranged between facing connection recesses, and the fixing member is plastically deformed so as to be pressed into the connection recesses, to thereby secure the facing members. By attaching the connecting member between the connection recesses by pressing thereinto, facing members of the head which comprise different materials can be reliably secured to each other. 
     According to the third embodiment of the present invention, there is provided a golfing iron club with a head provided with a face on a front surface and a shaft connecting portion on one side, and a shaft connected to the shaft connecting portion, the head comprising a head body formed with a sole, a cavity portion corresponding to the face formed in a front surface, a window opening formed inside the cavity portion and passing through to a rear surface side and a face member formed from a plate-like metallic material and fitted into the cavity portion. A first connection recess is formed in the cavity portion, a second connection recess is formed in a portion of the face member facing the first connection recess, and a fixing member is arranged between the first and the second connection recesses, and the fixing member is plastically deformed so as to be pressed into the first and the second connection recesses, to thereby secure the face member to the head body. By fitting the face member into the cavity portion on the head body, and reliably securing a desired location in the cavity portion to a desired location in the face member, the head body and the face member which comprise different materials can be reliably secured together. 
     According to the fourth embodiment of the present invention, there is provided a method of manufacturing a golfing iron club with a head provided with a face on a front surface and a shaft connecting portion on one side, and a shaft connected to the shaft connecting portion, the head comprising a head body formed with a sole, a cavity portion corresponding to the face formed in a front surface, a window opening formed inside the cavity portion and passing through to a rear surface side and a face member formed from a plate-like metallic material and fitted into the cavity portion. A first connection recess is formed in the cavity portion, a second connection recess is formed in a portion of the face member facing the first connection recess, and the face member is pressed into the cavity portion. At the time of the pressing, a fixing billet is arranged between the first and the second connection recesses and the fixing billet is plastically deformed so as to be pressed into the first and the second connection recesses, to thereby secure the face member to the head body. Since the fixing billet is plastically deformed at the time of pressingly inserting the face member into the cavity portion, so as to be fitted into the first and the second connection recesses, the head body and the face member comprising different materials can be reliably secured by a single operation.