The present invention is a divisional application of U.S. patent application Ser. No. 11/928,146, filed on Oct. 30, 2007, which is a continuation of U.S. patent application Ser. No. 11/461,132, filed on Jul. 31, 2006, which is a continuation-in-part of U.S. patent application Ser. No. 10/904,581, filed on Nov. 17, 2004, now U.S. Pat. No. 7,083,529.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
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OF THE INVENTION
1. Field of the Invention
The present invention relates to a golf club having an improved connection for interchanging a shaft with a golf club head.
2. Description of the Related Art
In order to improve their game, golfers often customize their equipment to fit their particular swing. Golf equipment manufacturers have responded by 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. Golf clubs that allow shaft and club head components to be easily interchanged facilitate this customization process.
One example is Wheeler, U.S. Pat. No. 3,524,646 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.
Another example is Walker, U.S. Pat. No. 5,433,442 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 and 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.
Still another example is Roark, U.S. Pat. No. 6,547,673 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 in the hosel of the club head, and an upper connector, which is secured in the lower portion of the shaft. The upper connector has a pin and a ball catch that protrude radially outward from the lower end of the upper connector. The upper end of the lower connector has a 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.
Two further examples are published applications to Burrows, U.S. Publication Numbers 2004/0018886 and 2004/0018887, both of which are for a Temporary Golf Club Shaft-Component Connection. The Burrows applications disclose a temporary connection that includes an adapter insert, a socket member, and a mechanical fastener. The adapter insert, which is mounted on a shaft, includes a thrust flange. The socket member, which is mounted on the other golf club component (e.g., a club head), includes a thrust seat for seated reception of the thrust flange. The mechanical fastener (e.g., a compression nut or a lock bolt) removably interconnects the adapter insert and the socket member.
The prior art temporary head-shaft connections have several disadvantages. First, they require that the golf club head have a conventional hosel for attachment. Second, these connections add excessive weight to the club head, thereby minimizing the amount of discretionary mass that may be distributed in the club head to optimize mass properties.
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OF THE INVENTION
The present invention provides an improved club head-shaft connection for cost-effective customization of golf clubs, while providing golfers with golf clubs that provide optimal performance. The connection, which does not require the club head to have a conventional hosel, enables quick and reliable assembly and disassembly of a shaft from the club head. In addition, the head-shaft connection of the present golf club provides a larger faying surface between the components without adding excessive weight. The reduced weight of the present connection enables more discretionary mass to be distributed to favorable locations in the club head to enhance its performance.
One aspect of the present invention is an interchangeable shaft for connection to a golf club head. The interchangeable shaft includes a shaft body and a sleeve. The sleeve, which is mounted on the tip end of the shaft body, has a lower section that includes a frustoconical portion, a keyed portion and a lower end of the sleeve. The frustoconical portion of the sleeve extends along at least one eighth of the length of the lower section. The sleeve is adapted to be mounted in a tube in the golf club head, such that the frustoconical portion of the sleeve is received in a tapered portion of the tube, and the keyed portion of the sleeve is received in a rotation prevention portion of the tube to prevent rotation of the shaft relative to the golf club head. The interchangeable shaft may be secured to the golf club head using a mechanical fastener.
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
FIG. 1 is a front plan view of a golf club in accordance with one embodiment of the present invention.
FIG. 2 is an exploded perspective view of a portion of the golf club of FIG. 1 illustrating the components of the head-shaft connection, including a sleeve, a tube, and a mechanical fastener.
FIG. 3 is an enlarged cross-sectional view taken generally along the line 3-3 in FIG. 1.
FIG. 4 is an enlarged cross-sectional view of the tube shown in FIG. 2.
FIG. 5 is an enlarged cross-sectional view of the sleeve shown in FIG. 2.
FIG. 6 is an exploded perspective view of a portion of a golf club in accordance with another embodiment of the present invention.
FIG. 7 is an enlarged cross-sectional view similar to FIG. 3, but of the golf club of FIG. 6.
FIG. 8 is an enlarged cross-sectional view of the tube shown in FIG. 6.
FIG. 9 is an enlarged cross-sectional view of the sleeve shown in FIG. 6.
FIGS. 10A-10C are enlarged, partial perspective views of alternative sleeves, illustrating various features that may be provided to help center a shaft in the opening of the sleeve.
FIGS. 10D-10F are top plan views of the alternative sleeves shown in FIGS. 10A-10C, respectively.
FIGS. 11A-11C are plan views of the tip end of alternative shafts having various features to help center the shaft in the opening of the sleeve.
FIG. 12 is similar to FIG. 3 but includes an O-ring to help retain the screw.
FIG. 13 is similar to FIG. 3 except that the shaft does not extend into the interior volume of the club head, and the club head includes a cap covering the opening in the sole.