Patent Publication Number: US-2009233728-A1

Title: Golf club with interchangeable shaft

Description:
I. FIELD OF THE INVENTION 
     This invention relates to golf clubs and more particularly to a golf club having an interchangeable golf club shaft by which any of a plurality of golf club shafts can be installed in the club head. 
     II. BACKGROUND AND SUMMARY OF THE INVENTION 
     Improvements in golf clubs enable golfers to customize their clubs to their particular swing. For example, modifications in the angle of the shaft to the club face can adjust the loft or the lie of the club. Similarly, different shafts have different characteristics that are better suited to a particular swing. Shafts are made from different materials, with the most popular being steel or graphite with different amounts of flex that are better suited for a given swing speed. Golf clubs that allow a player to easily change the shaft while utilizing the same club head allow a player to easily change the characteristics of a golf club without necessarily purchasing a completely new set of clubs. 
     Applicant&#39;s invention allows the player to easily change the playing characteristics of the golf club by changing the shaft attached to the club head. A standard diameter shaft is used eliminating the necessity for using specially manufactured shafts. The shaft has an adaptor mounted to the distal or bottom end of the shaft. The adaptor is threaded on the outside. The hosel on the golf club head has an internal bore that has complementary threads to threadedly receive the adaptor. The adaptor is screwed into the hosel so that the adaptor and the shaft are securely received into the club head. A spacer ring made of a softer metal than the hosel is placed between the hosel and a collar on the adaptor so that the adaptor is screwed down tightly against the spacer rather than against the hosel. This allows the shaft to be unscrewed when the shaft is to be changed. The shaft extends into the head so that it maintains the same feel and playability as a standard attached shaft. A set screw passes through the hosel and locks against the adaptor to securely retain the shaft in the club head. 
     III. OBJECTS AND ADVANTAGES 
     It is an object of the present invention to provide a golf club with interchangeable golf shafts. It is a related object to provide a golf club that uses a golf club shaft with an adaptor attached to its distal end, the adaptor received in the golf club head. 
     It is another object to provide a golf club in which the golf club shaft can be unscrewed from the golf club head and replaced with another golf club shaft having different characteristics. 
     Yet another object is to provide a golf club with an interchangeable shaft that uses a spacer between the adaptor and the hosel on the golf club head so that the adaptor is securely tightened against the spacer rather than directly against the golf club head. 
     Still another object is to provide a golf club that has a set screw passing through the hosel to secure the shaft mechanically within the golf club head. 
    
    
     
       IV. DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view with portions removed of the inventive golf club illustrating the various components including the shaft, club head, adaptor, spacer and set screw. 
         FIG. 2  is a front elevation view of the adaptor. 
         FIG. 3  is a cross sectional view of the adaptor and hosel with portions removed showing the shaft removed from the adaptor and the adaptor screwed against the spacer into the hosel, and the set screw screwed into the hosel. 
         FIG. 4A  is a cross sectional view with portions removed of an alternate embodiment in which the shaft is at an angle with respect to the longitudinal axis of the adaptor to increase the lie of the golf club head. 
         FIG. 4B  is a cross sectional view with portions removed of another alternate embodiment in which the shaft is at an angle with respect to the longitudinal axis of the adaptor to decrease the lie of the golf club head. 
     
    
    
     V. DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Turning first to  FIG. 1 , there is illustrated the first embodiment of a golf club  10  of the present invention. There is a conventional shaft  12  that is preferably made of steel or graphite. The shaft  10  has an upper or grasping end  14  and a bottom or distal end  16 . The diameter of the shaft is also of conventional design, with the bottom or distal end having a constant diameter. 
     A club head  18  can be a wood, iron, hybrid or any other golf club head as the invention is not restricted to being used on any one particular golf club head. The club head has a top portion  20 , a toe,  22 , a face  24 , a heel  26 , and a bottom  28 . There is a hosel  30  extending up from the top portion where it joins with the heel  26 . The hosel  30  has a diameter “D” that is greater than those of conventional golf clubs as will be described later. 
     The hosel  30  has a bore  32  with interior threads  34 . There is a top  36  which defines the end of the hosel and its length above the top portion  20  of the club head  18 . Preferably the bore  32  extends from the top  36  into the club head  18  beyond the top portion  20 . 
     An adaptor  40  provides the interface between the shaft  12  and the hosel  30 . The adaptor is preferably made of metal, but it can be made of hard plastic or other suitable material having the desired characteristics to accomplish the purpose of an interface piece. Looking at  FIGS. 2 and 3 , the adaptor  40  is substantially cylindrical in design. There is a passageway  41  extending from a top portion  42  to a bottom portion  50 . There is a pair of opposite flats  44  on the top portions  42  to provide a surface which can easily be engaged by a wrench or pliers. Below the top portion  42  is a center cylindrical portion  46  which has exterior threads  48 . Below the center portion  46  is the cylindrical bottom portion  50 . 
     As seen in  FIG. 3  there is a shoulder  52  in the bottom portion  50  of the passageway  41 . A stop  54  is inserted into the passageway  41  through the top portion  42  and pushed down to the shoulder  52  where it provides a fixed bottom plate. 
     The golf club  10  is assembled as follows. The distal end of the shaft  16  is inserted through a tapered sleeve  55  which provides a clean transition from the top portion  42  of the adaptor  40  to the shaft  12 . This is not required to practice the invention, but gives an aesthetically pleasing look to the finished club. The distal end  16  is then inserted into the passageway  41  in top portion  42  of the adaptor  40 . A small amount of glue or adhesive is placed in the passageway  41  or on the distal end of the shaft  16 . This helps in securely retaining the shaft in the adaptor, yet can be loosened by a skilled club maker to insert a different shaft. The distal end  16  is pushed into the adaptor  40  until the distal end  16  engages the stop  54 . This completes the assembly of the adaptor onto the end of the shaft. 
     A spacer  56 , which is a circular ring with a central hole, is placed over the bottom portion  50  of the adaptor. The central hole is slightly larger than the diameter of the center portion  46  of the adaptor so that the spacer can be slid up over the bottom portion  50 , past the center portion  46  and up to the top portion  42 . There is a ledge  58  separating the top portion  42  and the center portion  46 . The ledge  58  provides a shoulder which the spacer  56  engages and is secured against, and restricts any further lateral movement of the spacer  56  along the adaptor  40 . 
     The club head as illustrated in  FIG. 1  is a right handed club. Normally one would expect the adaptor  40  with the shaft inserted into it, to be screwed into the hosel by turning the shaft clockwise, such as required with right handed threads. However, the exterior threads  48  and the complementary interior threads  34  are left handed threads. This means that the shaft  12  is rotated counter clockwise in order to screw the adaptor into the hosel  30 . The shaft  12  is rotated until the ledge  58  on the top  42  securely engages the spacer  56  against the top of the hosel  36 . In this manner the spacer, which is preferably made of a softer metal than the adaptor or the hosel, absorbs the force of tightening. This allows the shaft to be more easily unscrewed when it is desired to change shafts. If one were to have a hard metal interface between the adaptor and the hosel, such as if the adaptor ledge  58  and the hosel  30  were both made of titanium or steel, then it would be extremely difficult to unscrew the two pieces after the golf club was used. The reason is that with left handed threads, each time the club strikes a ball, the impact transmits a tightening force to the adaptor. With the soft metal spacer  56  between the hosel and the adaptor, the spacer provides a shock absorber and interface which restricts the ultimate tightening forces between the adaptor and the hosel. In the case of a left handed club, the threads on the adaptor and the hosel will be right handed threads. 
     A mechanical securing means is provided in order to assist in securing the adaptor  40  in the hosel  30 . As seen in  FIGS. 1 and 3 , there is a hole  62  radially disposed in the hosel  30 . The hole  62  is threaded and receives a set screw  64 . Once the adaptor  40  is screwed into the hosel  30  to the fullest extent, the set screw  64  is turned and tightened against the center portion  46  of the adaptor  40 . To release the adaptor  40  from the hosel  30 , the set screw is merely reversed and unscrewed from engaging the center portion  46 . 
     In order to align the adaptor with the hosel when fully inserted, an indicator mark  66  is placed on the adaptor. A complementary indicator mark  68  is placed on the hosel. When the shaft  12  is properly and completed screwed into the hosel  30 , the two indicator marks,  66 ,  68  will be in alignment. The indicator marks also can be used to properly align a golf club grip on the shaft  12  with the club head  18 . 
     As can be seen, the shaft is of standard design and dimensions. For this reason, the passageway  41  of the adaptor must be properly dimensioned to receive the distal end  16  of the shaft  12 . The diameter of the center portion  46  will be greater than the diameter of the distal end  16 . Furthermore the diameter of the bore  32  in the hosel  30  will be the same as the diameter of the center portion  46 . This allows the use of standardly available shafts. When the adaptor  40  is screwed into the hosel  30 , the distal end  16  of the shaft  12  extends into the body of the golf club head  18 . This allows the golfer to have the same feeling as a conventionally mounted shaft. Furthermore the weight of the adaptor  40  is negligible so there is not substantial weight addition to the golf club  10 . 
     In the alternate embodiment as seen in  FIGS. 4A and 4B , the lie of the club can be adjusted. If a golfer tends to not place his hands or body in the proper position, it is possible that the bottom  28  of the club  18  will not lie flat on the ground. In order to compensate for this, it is possible to use a modified adaptor  40 . As seen in  FIG. 4A , the hosel  30  has a center line  70  which runs longitudinally through the center of the hosel. However, the passageway  41  is not formed along the center line of the adaptor. Instead it is offset by a predetermined amount in order to compensate for the players swing. Generally this will be one or two degrees. This is illustrated in  FIGS. 4A and 4B  as the angle between lines  70  and  72  which represent the center line of the hosel and the center line of the passageway. As seen, the lie of the club  18  can be varied by increasing the lie by two degrees as illustrated by arrow “B” in  FIG. 4A  and decreasing the lie by two degrees as illustrated by arrow “C” in  FIG. 4B . 
     In order to make sure that the lie is properly adjusted, the shaft is screwed into the hosel so that the indicator marks  66 ,  68  are aligned. This will insure that the club face is perpendicular to the direction which the player desires to hit the ball. Other angles can be formed in the adaptor  40  to accommodate the golfer. 
     Thus there has been provided a golf club with an interchangeable shaft that fully satisfies the objects and advantages set forth herein. While the invention has been described in conjunction with a specific embodiment, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit and scope of the appended claims.