BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a perspective view of a golf club with conventional breaks on a shaft of the club to show the relative position of a head of the club and a grip area of the club, and an expandable plug and an extension length are shown in an exploded fashion in the grip area of the club within a cut-away view of the grip;
FIG. 2 shows a cross-sectional view of a grip of the golf club with a plug secured within a hollow interior of the grip;
FIG. 3 shows a side exploded cross-sectional view of an expandable plug with extension length and a connector of the plug;
FIG. 4 shows an end view of the connector inserted into an expandable plug; and
FIG. 5 shows a representative kit of the disclosure comprising a blister package with two grips of different lengths and two plugs of different lengths along with instructions relating to the plugs.
DESCRIPTION OF THE EMBODIMENTS
As shown in FIG. 1, the golf club 20 comprises a head 22 with the shaft 24 extending between the head 22 and a grip area 26 of the club. Although a wood is shown in the drawing figures, the principles of the disclosure may be practiced with any golf club, including an iron or putter. The grip area 26 of the club extends partially down the shaft 24 a short distance toward the head 22 and is adapted to receive a grip 28 of the club. The shaft 24 is generally a cylindrical tapered tube with a hollow interior. Depending upon the type and length of the shaft, i.e., a composite (graphite) or steel, the wall thickness of the shaft may vary. To extend the length of the shaft, an expandable plug 30 is fitted in a hollow interior 32 of the shaft as shown in FIG. 1.
As shown in FIGS. 2 and 3, the plug comprises top and bottom wedge portions 34, 36 each with outer engagement surfaces 38, 40 and each with opposed angled faces 42,44. The angled faces 42,44 are adapted to abut and slide relative to one another as the plug 30 is installed in the shaft hollow interior. As will be explained below, when the plug is installed in the shaft hollow interior, the angled faces of the top and bottom wedge portions come into contact with each other and slide relative to one another, causing the top and bottom wedge portions to move in opposite directions and bring the top and bottom outer engagement surfaces into contact with a surface in the shaft hollow interior, for instance, the interior wall of the shaft. Although the top and bottom wedge portions are shown with cylindrically shaped outer engagement portions, other shapes may also be used and are considered within the scope of the invention.
Referring to FIGS. 2 and 3, the plug bottom wedge portion 36 has a threaded hole 46 that is adapted to receive a threaded connector. The plug top wedge portion 34 has an extension length 48 extending axially from the outer engagement surface 38. The top wedge portion has an access surface 50 opposite the angled face 42 and a first bore 52 extending from the access surface and partially through the top wedge portion. The first bore 52 forms an internal seat 54 in the top wedge portion for engaging a head of the threaded connector, as will be explained in greater detail below. The top wedge portion 34 has a second bore 56 that extends from the seat 54 to the angled face 42. The second bore 56 is larger than a diameter of a shaft of the connector and adapted to allow the top wedge portion to move laterally relative to the connector, as will be explained below in greater detail. The top wedge portion first bore 52 is larger than a diameter of the head of the connector and is adapted to allow the head of the connector head to slide therein to facilitate installation of the plug and connector, as will be explained below. The second bore 56 may extend partially through the bottom wedge portion 36 before terminating at the threaded hole 46.
The top wedge portion extension length 48 may be sized along its longitudinal length in accordance with a user's preference for a length of a golf club shaft. As shown in FIG. 3, the extension length 48 may have longitudinal ribs 58 circumferentially spaced about the extension length. The ribs 58 facilitate anchoring the grip 28 to the shaft of the club and prevent rotation of the grip on the shaft.
Referring again to FIGS. 2 and 3, a threaded connector 60 is directed through the first bore 52 in the access surface, through the second bore 56, and into the threaded hole 46 of the bottom wedge portion 36. Continued insertion or threading of the connector 60 into the bottom wedge portion 36 with the bottom wedge portion restrained draws the bottom wedge portion angled face 44 into abutting and sliding contact with the top wedge portion angled face 42. With the top and bottom wedge portions 34,36 in close proximity, the angled faces 42,44 of the wedge portions tend to engage each other and prevent rotation when the connector 60 is threaded further into the bottom wedge portion. As the connector 60 is threaded sufficiently into the threaded hole 46 of the bottom wedge portion and the connector head is drawn tightly against the internal seat 54 of the top wedge portion, the bottom wedge portion and top wedge portion engage and slide along their respective angled faces in opposite directions. The sliding motion generates relative lateral movement between the top and bottom wedge portions. The amount of relative lateral movement is in part determined by a diameter of the second bore 56 and a diameter of a shaft of the connector 60. Extending the second bore into the bottom wedge piece tends to increase the amount of relative lateral movement of the wedge pieces.
In operation, the plug 30 is inserted into the shaft hollow interior 32 in the grip area 26 of the shaft as shown in FIG. 1. Preferably, the outer engagement surfaces 38,40 of the plug top and bottom wedge portions 34,36 are inserted completely into the shaft hollow interior 32 such that only the extension length 48 extends from an end of the shaft. If the plug is being used in a golf club having an existing grip, the grip is removed from the grip area to expose the shaft hollow interior. However, as disclosed herein, a plug may be inserted into a hollow interior shaft of a new golf club during manufacture of the club and before any grip is installed. Once the outer engagement surfaces 38,40 of the top and bottom wedge portions are inserted into the shaft hollow interior 32, the threaded connector 60 is tightened thereby drawing the wedge portions respective faces into abutting and sliding contact and forcing the bottom wedge portion to move in a direction opposite the top wedge portion. This movement increases the size (for instance, the overall effective diameter) of the plug thereby allowing the plug to securely engage the shaft without the need for glue or other adhesives. With a tight mechanical fit provided solely by the plug, the user may fully utilize the club.
The grip 28 may be then installed over the extension length 48 (and/or the plug) and partially over the shaft 24 in the grip area 26 to provide an aesthetically pleasing look for the golf club. The grip may be attached to the shaft in the grip area and over the extension length with a suitable adhesives.
As an alternative, the grip 28 may be provided with the plug as described above, as an integral unit. As shown in FIG. 2, the plug may be securely held in a hollow interior of the grip 28 in a substantially coaxially alignment with the grip prior to its installation on a golf club. The plug may be secured to the grip at the access surface of the top wedge portion with adhesive or may be secured to the extension length with adhesive. Accordingly, when the plug is inserted into the hollow interior of the shaft as described above, the grip is installed in the grip area of the club in essentially one step.
In order to allow air to escape from the shaft, the threaded connector 60 may be provided with a hollow interior 70 that communicates with the shaft hollow interior 32. The connector may be a socket head type screw which may be tightened with a conventional hex wrench.
The plug 30 may be provided as a part of a kit 80 comprising a plug and a connector, as described previously, along with instructions 82 relating to the plug, for instance, installation of the plug in the shaft. The instructions may comprise graphics or illustrations or text, or advertising material promoting the kit. Other variations of the kit include providing one or more grips, the grip being integral with the plug (for instance, as shown in FIG. 2), a tool(s) for installation of the plug in the shaft, grips with different lengths, plugs with varying extension lengths, grips corresponding to the plugs, and/or connectors with varying lengths corresponding to the plugs. For instance, a kit as shown in FIG. 5 may include plugs with extension lengths varying in one-half inch increments and a set of matching grips for use with each plug. A kit may allow a user to select a plug from amongst a plurality of plugs based upon a desired extension length. A kit may provide a convenient way for a user to customize a length of the golf club shaft. For instance, if the user desires to change the length of the club, the user may remove the grip from the grip area, unthread the connector from the plug bottom wedge portion, remove the plug, and install a new desired plug. The grip(s) provided in the kit may then be used with the newly installed plug.
As shown in the drawings, the top wedge portion extension length and the top wedge portion outer engagement surface are monolithically formed. However, the top wedge portion extension length and top wedge portion outer engagement surface may be separate pieces held together in the shaft of the hollow golf club by the connector.
While specific embodiments have been described in detail in the foregoing detailed description and illustrated in the accompanying drawings, those with ordinary skill in the art will appreciate that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention, which is to be given the full breadth of the appended claims and any and all equivalents thereof.
Patent Application
20080081708
