DESCRIPTION OF THE PREFERRED EMBODIMENT

[0028] Referring initially to FIG. 1, a golf club in accordance with the present invention is shown and generally designated 13. As shown in FIG. 1, the golf club 13 includes a club head 14 having a hosel 15 and a hollow shaft 16. Although a metal-wood type head is shown in FIG. 1, it is to be appreciated that any type of golf club head known in the pertinent art including a wedge, iron, or putter can be used with the present invention. As further shown in FIG. 1, a swing weight plug 18 has been incorporated into the golf club 13. Functionally, the swing weight plug 18 is provided to selectively alter the swing weight of the golf club 13.

[0029] Referring now to FIG. 2, a first embodiment of the present invention is shown. As shown, the plug 18 includes a sleeve 20 for holding a high-density material 22 (see FIG. 3). Functionally, the plug 18 is designed for insertion into the head end 24 of the shaft 16 whereupon the plug 18 is attached to the shaft 16 (as shown in FIG. 1). With cross reference to FIGS. 1 and 2, it can be seen that after this attachment, the plug 18 and head end 24 of the shaft 16 are then inserted into the hosel 15 of the club head 14 and attached thereto.

[0030] With cross reference now to FIGS. 2 and 3, it can be seen that the sleeve 20 is shaped as a substantially hollow cylinder having an outer wall surface 26 and an inner wall surface 28. It is to be further appreciated that the inner wall surface 28 surrounds a cavity (which may be substantially cylindrical) that is provided to hold high density material 22. With this combination of structure, a longitudinal axis 30 passing through the cavity is defined for the cylindrical sleeve 20.

[0031] For the embodiment shown in FIG. 3, the high density material 22 is shaped as rods and disposed in the cavity surrounded by the inner wall surface 28 of the sleeve 20. As described and shown further below, the high-density material 22 can be prepared in various shapes and forms for disposal into the cavity of the sleeve 20. For example, the high density material 22 can be in the form of powder, one or more rods (as shown), one or more spheres, or can have a characteristic shape to include scrap material and/or scrap parts. In terms of composition, the high-density material 22 can be of various compositions to include Tungsten (sintered or unsintered), Tungsten alloys (sintered or unsintered and to include Tungsten Carbide), steel, stainless-steel, copper, brass, lead, lead alloys or any other high-density material known in the pertinent art. Preferably, Tungsten is used as the high density material 22 due to its high density and relatively low toxicity. The Tungsten can be in the form of Tungsten powder, Tungsten rod or recovered Tungsten scrap (i.e. Tungsten having a characteristic shape).

[0032] For the embodiment shown in FIG. 2, the sleeve 20 is preferably made of a plastic material such as a polypropylene. For embodiments wherein a plastic sleeve 20 is preferred, an injection molding process can be used to prepare the sleeve 20. The plastic sleeve 20 can be further characterized as having sufficient elasticity to produce interference fit type attachments when the sleeve 20 is engaged with the golf club shaft 16 (see detailed description below).

[0033] With cross reference now to FIGS. 2 and 4, it can be seen that the sleeve 20 is formed with a plurality of elongated, axially aligned ridges 32 that project from the outer wall surface 26 of the cylindrical sleeve 20. Preferably, three or more ridges 32 are symmetrically distributed around the cylindrical sleeve 20 allowing the sleeve 20 to be centered when inserted into a golf shaft 16 (See FIG. 5). For the present invention, the ridges 32 are provided to establish an interference fit between the sleeve 20 and the shaft 16. For purposes of the present disclosure, an interference fit is defined as: a negative fit necessitating force sufficient to cause expansion in one mating part, or contraction in the other, during assembly.

[0034] To effect an interference fit between the sleeve 20 and the shaft 16, the sleeve 20 is sized relative to the shaft 16. More specifically, as shown in FIG. 3, the outer wall surface 26 of the sleeve 20 has a diameter, D₁. Also, the shaft 16 defines an inner diameter, D₂, at the head end 24 (end 24 numbered in FIG. 2) where the plug 18 is to be inserted and attached. Further, as shown in FIG. 5, each uncompressed ridge 32 defines a ridge radius, r₃, measured from the axis 30 of the sleeve 20 to the radial extremity of each ridge 32. Accordingly, a corresponding diameter, D₃, equal to 2×r₃ is defined for the sleeve 20 and represents a diameter of a circle that extends around the radial extremity of each uncompressed ridge 32.

[0035] For this embodiment of the present invention, the sleeve 20 is sized relative to the shaft 16 wherein D₁<D₂<D₃. With this cooperation of structure, as best seen in FIG. 4, each ridge 32 must compress radially during insertion of the sleeve 20 into the shaft 16. On the other hand, as best seen in FIG. 3, with the sleeve 20 fully inserted into the shaft 16, a gap 34 remains between the outer wall surface 26 of the sleeve 20 and the shaft 16. As indicated by the first directional arrow 36, the gap 34 allows air to flow from the bore 38 of the hosel 15 and into the shaft 16 during insertion of the shaft 16 (and plug 18) into the hosel 15.

[0036] For the embodiment of the present invention shown in FIG. 2, a cylindrical flange 40 is formed at one end of the sleeve 20, defining a flange diameter, D₄. The sleeve 20 is further formed with a plurality of spacers 42 that extend from the flange 40 and along the outer wall surface 26 of the sleeve 20. It is to be appreciated that the flange 40 and spacers 42 prevent the entire sleeve 20 from being inserted in the shaft 16. More specifically as shown in FIG. 4, with this structural combination the spacers 42 seat against the head end 24 of the shaft 16 and maintain the flange 40 spaced from the head end 24 of the shaft 16. As indicated by second directional arrow 44 in FIG. 3, this spacing allows air from the bore 38 of the hosel 15 to flow between the spacers 42 and into the gaps 34 that have been created between the outer wall surface 26 of the sleeve 20 and the shaft 16. For this embodiment of the present invention, the diameter, D₄ of the flange 40 is sized to be smaller than the diameter, D₅ of the bore 38 of the golf club hosel 15, D₄<D₅ (note; the diameter, D₅ of the bore 38 is approximately equal to the outer diameter of the shaft 16). This sizing of the flange 40 allows air from the bore 38 of the hosel 15 to flow around the flange 40 and then between the spacers 42.

[0037] To assemble the club 13, a high density material 22 such as Tungsten rod or powder is first disposed in the sleeve 20 and secured (see FIG. 3). Next, as best seen with cross reference to FIGS. 2 and 4, the end of the sleeve 20 opposite the flange 40 is inserted into the head end 24 of the golf shaft 16 until the spacers 42 seat against the head end 24 of the shaft 16. An interference fit that is formed between the ridges 32 of the sleeve 20 and the shaft 16, attaches and secures the sleeve 20 to the shaft 16 (see FIG. 4). With cross reference to FIGS. 1 and 2, it can be seen that with the swing weight plug 18 attached to the shaft 16, the shaft 16 and plug 18 are inserted into the bore 38 of the hosel 15 of the club head 14. During insertion, air from the cavity of the club head 14 and/or bore 38 of the hosel 15 that is displaced by the shaft 16 and plug 18 is able to escape through the shaft 16. More specifically, a pathway (see first and second directional arrows 36, 44 in FIG. 3) is established that allows air from the club head 14 to flow around the flange 40, between the spacers 42 and then through the gaps 34 that have been created between the outer wall surface 26 of the sleeve 20 and the shaft 16.

[0038] Referring now to FIG. 6, an alternate embodiment for a swing weight plug 118 is shown. Unlike the embodiment shown in FIGS. 1-5, the FIG. 6 embodiment includes ridges 132 on the outer wall surface 126 of the sleeve 120 that extend helically about the longitudinal axis 130 of the sleeve 120. These helically shaped ridges 132 facilitate insertion of the plug 118 into the shaft 16 (shown in FIG. 1), by allowing the plug 118 to be rotated about the longitudinal axis 130 during insertion into the shaft 16. Also shown in FIG. 6, the sleeve 120 is further formed with a flange 140 to limit travel of the sleeve 120 into the shaft 16. It can also be seen that at the end 46 of the sleeve 120, an opening 48 is provided. It is to be appreciated that this opening 48 extends from the end 46, into the sleeve 120 and through the flange 140. Functionally, the opening 48 allows air to escape through the sleeve 120 during insertion of the shaft 16 into the hosel 15 as described above. More specifically, a pathway can be maintained in the sleeve 120 through the high density material 22, allowing air from the hosel 15 to pass through the opening 48. For example, holes in the high density material 22 can be provided to allow air to pass from the hosel 15 through the opening 48.

[0039] FIG. 7 shows another embodiment of a swing weight plug 218 in accordance with the present invention. More specifically, as shown, the plug 218 is configured for use with a golf club head 214 having a pin 50. As further shown, the pin 50 is sized for insertion into the shaft 216 and attachment thereto. Unlike the embodiments described above, the plug 218 is configured to be fully inserted into the shaft 216 (i.e. plug 218 does not contain a flange 40 like the embodiment shown in FIG. 2). To assemble, the plug 218 is inserted into the shaft 216. Next, the pin 50 is inserted into the shaft 216, pushing the plug 218 further into the shaft 216. An adhesive can be applied to the pin 50 to secure the pin 50 to the shaft 216. An interference fit between the plug 218 and the shaft 216 is established by the ridges 232, as described above.

[0040] Referring now to FIG. 8, another embodiment of a swing weight plug 318 is shown. For this embodiment, the ridges 332 are formed as flaps that project from the outer wall surface 326 of the sleeve 320 and extend somewhat azimuthally to a tip 52, as shown. The flap shape of the ridges 332 allows a single size of plug 318 to be used to establish an interference fit with shafts 16 (shown in FIG. 1) having a range of inside diameters. If desired, an adhesive such as epoxy can be applied to the ridges 332 and/or outer wall surface 326 to augment the attachment of the plug 318 to the shaft 16.

[0041] As seen in FIG. 9, the high density material 22 can be formed as bars for insertion into the sleeve 20 (thus, exploded FIG. 9 corresponds to the embodiment shown in FIGS. 2-5. It is to be appreciated that the sleeve 20 can be formed with an opening at either end to allow the high density material 22 to be inserted into the sleeve 20. Referring now to FIG. 10, it can be seen that the high density material 422 can be formed as spheres for insertion into the sleeve 420. As shown in FIG. 11, the high density material 522 can have a characteristic shape to include scrap material and/or scrap parts.

[0042] Referring now to FIG. 12, another embodiment of a swing weight plug 618 in accordance with the present invention is shown. Unlike the embodiment shown in FIG. 2, the sleeve 620 does not contain ridges 32 to attach the plug 618 to the shaft 16. Instead, for the FIG. 12 embodiment, an adhesive such as an epoxy is preferably used to bond the sleeve 620 to the shaft 16.

[0043] As described above, each of the embodiments shown, (i.e. FIGS. 2, 6, 7, 8, 10, 11 and 12) can include a plastic sleeve 20, 120, 220, 320, 420, 520, 620 that holds a high density material 22, 422, 522, which may be in the form of powder, spheres, rods or may have a characteristic shape. Alternatively, in accordance with the present invention, each of the sleeves 20, 120, 220, 320, 420, 520, 620 may be constructed of a filled polymer. For example, a high density filler such as Tungsten powder can be mixed with a polymer such as polypropylene, epoxy or polyurethane and the mixture used to mold the sleeve 20, 120, 220, 320, 420, 520, 620. When the sleeve 20, 120, 220, 320, 420, 520, 620 is prepared using a high density filler, the sleeve 20, 120, 220, 320, 420, 520, 620 can be used alone or together with a high density material 22 in the form of powder, spheres, rods, etc. Stated another way, when the sleeve 20, 120, 220, 320, 420, 520, 620 is prepared using a high density filler, the cavity of the sleeve 20, 120, 220, 320, 420, 520, 620 can be filled with a high density material 22, or the sleeve 20, 120, 220, 320, 420, 520, 620 can be used with an empty cavity. It is to be further appreciated that sleeves 20, 120, 220, 320, 420, 520, 620 made of a filled polymer can be solid (i.e. without a cavity). For example, plug 318 shown in FIG. 8 can be molded of a filled polymer without a cavity (i.e. solid) in accordance with the present invention.

[0044] In a preferred embodiment of the present invention, a mixture of a polymer and secondary Tungsten powder with spheroidal grains and having a tap powder density between approximately ten grams per cubic centimeter (10 g/cc) and approximately twelve grams per cubic centimeter (12 g/cc) is used to prepare the sleeve 20, 120, 220, 320, 420, 520, 620. A more detailed description of secondary Tungsten powder having spheroidal grains is given in co-pending U.S. patent application Ser. No. 10/104,560 entitled “Weighted Golf Club Head” to Joseph Sery that was filed on Mar. 21, 2002, the disclosure of which is hereby incorporated herein by reference. Alternatively, virgin Tungsten powder or powdery Tungsten that is crushed from sintered Tungsten can be used as the high density filler to prepare the sleeve 20, 120, 220, 320, 420, 520, 620.

[0045] While the particular swing weight plugs as herein shown and disclosed in detail are fully capable of obtaining the objects and providing the advantages herein before stated, it is to be understood that they are merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as described in the appended claims.