FIELD OF THE INVENTION
- BACKGROUND OF THE INVENTION
This invention generally relates to golf clubs, and more specifically to golf clubs having an improved hosel connection that provides interchangeability between a shaft with a club head.
In order to improve their game, golfers often customize their equipment to fit their particular swing. In the absence of a convenient way to make heads and shafts interchangeable, a store or a business offering custom fitting must either have a large number of clubs with specific characteristics, or must change a particular club using a complicated disassembly and reassembly process. It, for example, a golfer wants to try a golf club shaft with different flex characteristics, or use a club head with a different mass, center of gravity, or moment of inertia, in the past it has not been practical to make such changes. Golf equipment manufacturers have been increasing the variety of clubs available to golfers. For example, a particular model of a driver-type golf club may be offered in several different loft angles and lie angles to suit a particular golfer's needs. In addition, golfers can choose shafts, whether metal or graphite, and adjust the length of the shaft to suit their swing. Recently, golf clubs have emerged that allow shaft and club head components, such as adjustable weights, to be interchanged to facilitate this customization process.
One example is U.S. Pat. No. 3,524,646 to Wheeler for a Golf Club Assembly. The Wheeler patent discloses a putter having a grip and a putter head, both of which are detachable from a shaft. Fastening members, provided on the upper and lower ends of the shaft, have internal threads, which engage the external threads provided on both the lower end of the grip and the upper end of the putter head shank to secure these components to the shaft. The lower portion of the shaft further includes a flange, which contacts the upper end of the putter head shank, when the putter head is coupled to the shaft. This design produces an unaesthetic bulge at the top of the shaft and another unaesthetic bulge at the bottom of the shaft.
Another example is U.S. Pat. No. 5,433,442 to Walker for Golf Clubs with Quick Release Heads. The Walker patent discloses a golf club in which the club head is secured to the shaft by a coupling rod and a quick release pin. The upper end of the coupling rod has external threads that engage the internal threads formed in the lower portion of the shaft. The lower end of the coupling rod, which is inserted into the hosel of the club head, has diametric apertures that align with diametric apertures in the hosel to receive the quick release pin.
Another example is U.S. Patent Pub. No. 2006/0105855 A1 to Cackett et al. for a Golf Club with Interchangeable Head-Shaft Connections. The Cackett publication discloses a golf club that uses a sleeve/tube arrangement instead of a traditional hosel to connect the interchangeable shaft to the club head in an effort to reduce material weight and provide for quick installation. A mechanical fastener (screw) entering the club head through the sole plate is used to secure the shaft to the club head.
Still another example is U.S. Pat. No. 6,547,673 to Roark for an Interchangeable Golf Club Head and Adjustable Handle System. The Roark patent discloses a golf club with a quick release for detaching a club head from a shaft. The quick release is a two-piece connector including a lower connector, which is secured to the hosel of the club head, and an upper connector, which is secured to the lower portion of the shaft. The upper connector has a pin and a ball catch that both protrude radially outward from the lower end of the upper connector. The upper end of the lower connector has a corresponding slot formed therein for receiving the upper connector pin, and a separate hole for receiving the ball catch. When the shaft is coupled to the club head, the lower connector hole retains the ball catch to secure the shaft to the club head.
Other published patent documents, such as U.S. Pat. No. 7,083,529 and U.S. patent application publication numbers 2006/0287125, 2006/0293115, 2006/0293116 and 2006/0281575, disclose interchangeable shafts and club heads with anti-rotation devices located therebetween.
- SUMMARY OF THE INVENTION
There remains a need in the art for golf clubs with an improved connection that provides a method for quickly and easily interchanging the shaft, removable weights and other attachments with the club head.
The invention is directed to a releasable connection system for assembling a golf club. The inventive connection system provides an interchangeability between a shaft and a club head that imparts minimal visual impairment and club mass fluctuation while optimizing customization.
In one embodiment, the present invention includes a connection system that comprises a two-part hosel, wherein a first hosel part is connected to the shaft and a second hosel part is connected to the club head, and an anti-rotation device is disposed between the first and second hosel parts, and the anti-rotation device is located above the club head. The anti-rotation device can have a first serrated surface disposed on the first hosel part and a second corresponding serrated surface disposed on the second hosel part. The first and second serrated surfaces mate to minimize relative rotation between the shaft and the club head.
In another embodiment, the connection system comprises a hollow sole insert affixed in a hosel bore proximate a sole of the club head, wherein a first key is disposed on an internally threaded distal end of the shaft and a second corresponding key is disposed on the sole insert. As a fastener is inserted through the sole insert and into the threaded distal end of the shaft to connect the shaft to the club head the first and second keys mate with each other to minimize relative rotation between the shaft and the club head.
BRIEF DESCRIPTION OF THE DRAWINGS
In yet another embodiment, the connection system comprises a spring loaded bayonet mount, wherein the spring has a spring constant from about 5 pounds-force to about 100 pounds-force and wherein the spring loaded bayonet mount is located above the club head. The bayonet mount comprises at least one post disposed on the shaft and at least one corresponding channel disposed on a hosel of the club head and the bayonet mount further comprises a spring disposed within the hosel. The channel may have a reduced diameter section sized and dimensioned to releasably retain said post.
In the accompanying drawings, which form a part of the specification and are to be read in conjunction therewith and in which like reference numerals are used to indicate like parts in the various views:
FIG. 1 is an exploded view of an exemplary driver club showing a shaft, a club head and a first embodiment of the inventive connection system;
FIG. 2 is an exploded view of the two-part hosel of the connection system of FIG. 1;
FIG. 3 is a perspective view of the assembled shaft;
FIG. 4 is a partial cross-sectional view of the connection system of FIG. 1
FIG. 5 is a perspective view of the assembled driver club of FIG. 1;
FIGS. 6 and 7 are perspective views a second embodiment of the inventive connection system; and
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 8 is an exploded view of an exemplary driver club and a third embodiment of the inventive connection system; FIG. 8A is an alternative of the third embodiment.
The present invention is directed to a quick connection system for connecting the shaft to a club head and for changing the shaft or the club head to optimize the golfer's strength to the playing conditions. Such a system can be utilized or customized for various applications, including, but not limited, to the shaft-club head connection, the insertion of adjustable weights in the club head, and the connection of a sole plate to the club head. Several embodiments of the present invention are described below.
Inventive connection system 10 is designed for club fitters to repeatedly change shaft or club head combinations during a fitting session. Inventive connection system 10 is designed to give fitting accounts maximum fitting options with a system that is fast and easy to use
Referring to FIGS. 1 and 2, connection system 10 releasably connects club head 12 to shaft 14, such that different shafts 14 can be connected to different club heads 12. Connection system 10 comprises a two-part hosel, i.e., shaft serrated hosel 16 and driver serrated hosel 18 and internally threaded shaft insert 20. Serrated surface 17 of shaft hosel 16 and serrated surface 19 of driver hosel 18 are sized to mate with each other to minimize or prevent relative rotation between shaft hosel 16 and shaft hosel 18. Preferably, each serrated surface comprises a plurality of corresponding teeth. Connection system 10 further comprises driver sole insert 22 and screw 24, which are connected to club head 12 on the sole side, as shown.
As best shown in FIG. 3, shaft 14 is at least partially hollow and is sized and dimensioned to receive and retain internally threaded shaft insert 20 therewithin. Preferably, shaft insert 20 is securely attached to shaft 14 by means of adhesives, epoxies or similar materials. Shaft serrated hosel 16 is sized and dimensioned to fit on the outside of shaft 14. A predetermined length 26 of shaft 14 is positioned below shaft serrated hosel 16 for insertion into club head 12. The internal threads of shaft insert 20 are adapted to receive the external threads of fastener 24, such as screw 24.
As best shown in FIG. 4, driver serrated hosel 18 has external threads, as shown, and is threaded into the top of bore 28 of club head 12. Adhesives or epoxies can also be used to affix driver serrated hosel 18 to bore 28. At the bottom of bore 28, driver sole insert 22 is inserted into bore 28 and affixed therein. Preferably, driver sole insert 22 is serrated or threaded on the outside surface to increase the surface area to adhesives or epoxies. The assembled shaft 14 with shaft insert 20 and shaft hosel 16 as shown in FIG. 3 is inserted through driver hosel 18 and into bore 18. Screw 24 is inserted through driver sole insert 22 and is threaded into shaft insert 20 to secure shaft 14 to club head 12. Preferably, distal tip 30 of shaft 14 is spaced apart from the top of driver sole insert 22 and shaft 14 and driver sole insert 22 is separated by gap 32. Gap 32 ensures that screw 24 can fully pull shaft 14 downward toward the sole of club head 12 so that serrated surfaces 17 and 19 fully engage each other to minimize relative rotation between the two hosels 16 and 18 thereby minimizing relative rotation between shaft 14 and club head 12. In other words, gap 32 ensures that screw 24 does not “bottom out” inside threaded shaft insert 20 so that serrated hosels 16 and 18 can fully mate with each other.
Optionally, bore 28 has ledge 34 shown in FIG. 4 formed integrally thereon, e.g., through the casting process, to abut driver sole insert 22 to provide additional structural support for driver sole insert 22 and screw 24. Alternatively, driver sole insert 22 can be formed integrally on bore 28. These alternatives are applicable to all of the embodiments described herein.
Referring to FIG. 5, a fully assembled golf club is shown. Serrated hosels 16 and 18 form a single hosel and the serrated lines 16 and 17 separating the two hosels are preferably located above the top of club head 12. The advantage of locating the anti-rotation device, i.e., shaft serrated hosel 16 and driver serrated hosel 18, above the club head is that no additional mass is added, thereby preserving the mass properties of the club head and eliminating a protrusion at the shaft/hosel intersection. The anti-rotation device uses a standard hosel to make both the shaft serrated hosel and the driver serrated hosel This means there is no weight gained or lost from the device, which in turn means no change in moment of inertia or center of gravity. Furthermore, serrated lines 16 and 17 add a visual distinction to the golf club and readily identify the golf club as an interchangeable golf club.
Driver sole insert 22 and shaft threaded insert 20 can be made out of aluminum, stainless steel or titanium. Screw 24 can be any threaded screw, and is preferably a TORX™ drive flat head screw and the sole insert 22 is tapered so that the head of screw 24 can be flushed with sole insert 22, as best shown in FIG. 4.
Referring to FIGS. 6 and 7, another embodiment of connection system 10 is shown. In this embodiment, the two-part hosel of the first embodiment is replaced by a keyed anti-rotation device. This keyed anti-rotation device comprises angled cut-out 36 on the distal tip of shaft 14. Shaft 14 is also hollow and has threaded shaft insert 20 inserted therein and conventional hosel 40 disposed thereon. Driver sole insert 22′ has angled surface 38 sized and dimensioned to match cut-out 36. In this embodiment, shaft 14 is inserted into driver sole insert 22′, and angled cut-out 36 is keyed to angled surface 38 as screw 24 is threaded into shaft insert 20 to minimize or prevent relative rotation between shaft 14 and driver sole insert 22′/club head 12. An advantage of this embodiment is that an anti-rotation device can be added without adding substantial weight to the club head thereby minimizing the effect on the club's swing weight.
Referring to FIG. 8, another embodiment of connection system 10 is shown. In this embodiment, bore 18 does not extend through club head 12. Club head 12 has hosel 42, which has at least one and preferably two or more channels 44. Channel 44 has entry leg 46 and locking leg 48. Leg 46 is adapted to receive post 50 on shaft 14. After post 50 travels through entry leg 46, it passes transverse leg 47 before being received and held in locking leg 48. Disposed within hosel 42 is spring 52 which exerts an upward force on shaft 14 to hold securely post 50 in locking leg 48. Spring 52 is selected so that it can exert a sufficient force to hold post 50 within channel 44. Preferably, spring 52 has a spring constant from about 5 to about 100 pounds-force/inch. More preferably, the spring constant can be in the range of about 20 to about 75 pounds-force/inch and most preferably about 33 pounds-force/inch. A golfer can conveniently insert shaft 14 into hosel 42 after aligning post 50 to leg 46. Thereafter, shaft 14 is rotated along transverse leg 47 and afterward spring 52 pushes shaft 14 up leg 48. Post 50 and channel 44 is also known as a bayonet mount or connection.
Although channel 44 is illustrated as a “J-shaped” channel, it can have any shape, e.g., “U”, “L”, “S”, “V” or “W” shape. Also, preferably leg 46 is preferably deep so that as post 50 is moved down into hosel 42, more of shaft 14 overlaps hosel 42 to increase mechanical stability. Alternatively, the top of locking leg 48 may have a reduced diameter section to hold post 50 by press-fit or by increased friction. As illustrated in FIG. 8A, the reduced diameter section can be a triangular section. The reduced diameter section can also be a figure-eight or waist section.
While the embodiments of the present invention are illustrated with driver-type clubs, it is understood that any type of golf clubs can utilize inventive connection system 10.
While it is apparent that the illustrative embodiments of the invention disclosed herein fulfill the objectives stated above, it is appreciated that numerous modifications and other embodiments may be devised by those skilled in the art. Therefore, it will be understood that the appended claims are intended to cover all such modifications and embodiments, which would come within the spirit and scope of the present invention.