Swing weight plug and method for manufacturing a golf club having a pre-selected swing weight

Abstract

A plug for use in a golf club to selectively alter the swing weight of the golf club includes a sleeve for holding a high-density material such as Tungsten (sintered or unsintered) in the form of powder, rods or scrap parts. The sleeve is preferably made of plastic and shaped as a substantially hollow cylinder having an outer wall surface. The sleeve is further formed with a plurality of elongated ridges that project from the outer wall surface of the cylindrical sleeve. The ridges define a ridge diameter measured around the radial extremity of each ridge. This ridge diameter is sized to be larger than the inner diameter of the shaft at the end where the plug will be inserted. When the sleeve is inserted into the shaft, the ridges are compressed to establish an interference fit between the ridges and the shaft that anchors the sleeve to the shaft.

Description

FIELD OF THE INVENTION

[0001] The present invention pertains generally to golf clubs and methods for manufacturing golf clubs. More particularly, the present invention pertains to methods for manufacturing golf clubs having a pre-selected swing weight. The present invention is particularly, but not exclusively, useful as a swing weight plug and a method for manufacturing a golf club incorporating a swing weight plug.

BACKGROUND OF THE INVENTION

[0002] Swing weight is the measure of a golf club's resistance to being swung in a circle. For golfers having an easy, graceful swing, a club having a relatively heavy swing weight is preferable. On the other hand, golfers who swing quickly generally prefer a club having relatively less swing weight so that the club can rotate around the golfer's pivot point as fast as the golfer's body is rotating. With this in mind, club manufacturers generally offer a variety of swing weights for each style of club they market.

[0003] In more technical terms, swing weight is the `moment of inertia` of the club measured relative to a selected point on the club. Standardized procedures use a static measurement to determine swing weight that approximates the moment of inertia about a point 14-inches from the grip end of the shaft. Using this procedure, swing weights are expressed according to an arbitrary scale in which the swing weights are scaled into groups A, B, C, D, E, and F with each group further divided into tenths. In this scale, a typical woman's club will be close to about C-4 and a man's club might have a swing weight of about D-2. A common procedure used to increase the swing weight of an off-the-shelf club is to apply lead tape to the club head. Such an application of lead tape may increase the swing weight of the golf club from D-2 to about D-5.

[0004] Absent the implementation of specific provisions to alter the swing weight of a golf club, the primary factors affecting swing weight are the length of the shaft and the weight of the club head. Unfortunately, the manufacturing processes used to produce golf club heads are not always perfect. In fact, under normal manufacturing conditions, it is to be expected that club head weights can vary in weight by as much as 1-4 grams within a single club head production run. This variation in club head weight leads to an undesirable fluctuation in swing weights. To summarize, although a club head/shaft combination is designed to have a desired swing weight, defects in the manufacturing process produce clubs having an incorrect swing weight that must be corrected, typically before the club head is assembled onto the shaft.

[0005] As indicated above, different types of golfers prefer golf clubs having different swing weights. Unfortunately, it is generally cost prohibitive for golf club manufacturers to design, dimension and manufacture a unique club head for each desired swing weight. Instead, it is customary to design a club head suitable for producing a club having the lightest swing weight required. Weights can then be added to the low swing weight club to produce clubs having higher swing weights. Heretofore, a common method used to increase swing weight has been to incorporate lead plugs into the club that weigh approximately 2-18 grams. More specifically, the lead plugs have been inserted into the shaft (at the club head end) and bonded to the inner wall of the shaft using an epoxy.

[0006] This use of lead plugs has several drawbacks. For one, lead is toxic. Because of this toxicity, special (and costly) safety precautions are required to prevent workers from lead exposure. Additionally, special precautions must be taken to safely dispose of unwanted lead (and items contaminated with lead). Otherwise, an adverse environmental impact will likely occur. Another drawback associated with lead plugs that are bonded to a shaft is that the plugs and/or epoxy often crack resulting in a golf club that rattles during a play. Also, the use of an epoxy to bond the lead plug to the shaft complicates club assembly and is time consuming.

[0007] It is an object of the present invention to provide methods and devices suitable for the purposes of altering a golf club to produce a club having a pre-selected swing weight. It is another object of the present invention to provide a swing weight plug that is constructed using relatively non-toxic materials and processes. It is yet another object of the present invention to provide a swing weight plug that, when incorporated into a shaft, allows air from the cavity of a golf club head to be released during installation of the club head onto the shaft. Yet another object of the present invention is to provide methods for increasing the swing weight of a golf club which are easy to use, relatively simple to assemble, and comparatively cost effective.

SUMMARY OF THE PREFERRED EMBODIMENTS

[0008] The present invention is directed to a swing weight plug for use in constructing a golf club to selectively alter the swing weight of the golf club. For the present invention, the plug includes a sleeve for holding a high-density material. In overview, the plug is designed for insertion into the end of the shaft whereupon the plug is attached to the shaft. After this attachment, the plug and shaft end are inserted into the hosel of the club head and attached thereto.

[0009] In greater structural detail, the sleeve is preferably shaped as a substantially hollow cylinder having an outer wall surface and an inner wall surface. The inner wall surface surrounds a substantially cylindrical cavity that is provided to hold the high density material. Thus, a longitudinal axis passing through the cavity is defined for the cylindrical sleeve. Preferably, Tungsten (sintered or unsintered) is used as the high density material. The Tungsten can be in the form of Tungsten powder, Tungsten rod or Tungsten scrap (i.e. Tungsten having a characteristic shape). On the other hand, the sleeve is preferably made of an injection molded plastic such as a polypropylene. In some embodiments, a high-density sleeve is made of a filled polymer. More specifically, the sleeve can be made of a mixture of secondary Tungsten powder and a polymer such as epoxy. As such, the sleeve can be further characterized as having sufficient elasticity to produce an interference fit type attachment when the sleeve is engaged with the golf club shaft (see detailed description below).

[0010] To secure the sleeve to the club shaft, the sleeve is formed with a plurality of elongated, axially aligned ridges that project from the outer wall surface of the cylindrical sleeve. Preferably, three or more ridges are symmetrically distributed around the cylindrical sleeve allowing the sleeve to be centered when inserted into a golf shaft. Importantly, the diameter of the sleeve's outer wall surface (D.sub.1) and the radial extension of each ridge from the outer wall surface are sized relative to the golf shaft. More specifically, the shaft defines an inner diameter (D.sub.2) at the end where the plug is to be inserted and attached. Further, the ridges define a ridge diameter (D.sub.3), measured as the diameter of a circle that passes through the radial extremity of each ridge. For the present invention, the sleeve is sized wherein D.sub.1<D.sub.2<D.sub.3.

[0011] With this cooperation of structure, the ridges must compress radially during insertion of the sleeve into the golf shaft. On the other hand, with the sleeve fully inserted into the golf shaft, a gap remains between the outer wall surface of the sleeve and the golf shaft. As detailed further below, this gap allows air to escape from the club head during insertion of the shaft (and plug) into the hosel of the club head.

[0012] In a preferred embodiment of the present invention, a cylindrical flange is formed at one end of the sleeve, centered on the longitudinal axis. This cylindrical flange defines a flange diameter (D.sub.4). The end of the sleeve opposite the flange is inserted into the club shaft and the flange is provided to prevent the entire sleeve from being inserted into the shaft. The sleeve is further formed with a plurality of spacers that extend from the flange and along the outer wall surface of the sleeve. With this structural combination, the spacers seat against the end of the shaft and maintain the flange at a pre-selected distance from the end of the shaft. This spacing allows air from the club head to flow between the spacers and into the gaps that have been created between the outer wall surface of the sleeve and the shaft. For the present invention, the diameter (D.sub.4) of the flange is sized to be smaller than the bore diameter (D.sub.5) in the golf club hosel, D.sub.4<D.sub.5 (note; this bore diameter is approximately equal to the outer diameter of the shaft). This sizing allows air from the club head to flow around the flange and then between the spacers.

[0013] To summarize, a high density material such as Tungsten is disposed in the sleeve and secured. Next, the sleeve end opposite the flange is inserted into the end of the golf shaft until the spacers seat against the shaft end. An interference fit that is formed between the ridges of the sleeve and the shaft attaches and secures the sleeve to the shaft. With the swing weight plug attached to the shaft, the shaft and plug are inserted into the hosel bore of the club head. During insertion, air from the club head cavity and/or hosel bore that is displaced by the shaft and plug is able to escape through the shaft.

[0014] More specifically, a pathway is established that allows air from the club head to flow around the flange, between the spacers and then through the gaps that have been created between the outer wall surface of the sleeve and the shaft.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The novel features of this invention, as well as the invention itself, both as to its structure and its operation, will be best understood from the accompanying drawings, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which:

[0016] FIG. 1 is a perspective view of a portion of a golf club having a swing weight plug in accordance with the present invention;

[0017] FIG. 2 is an exploded perspective view showing a portion of a club head hosel, a swing weight plug and a portion of a golf club shaft;

[0018] FIG. 3 is a sectional view of a swing weight plug, a portion of a club head hosel, and a portion of a golf club shaft as seen along line 3-3 in FIG. 2, shown after the swing weight plug has been inserted into and attached to the shaft and the shaft has been inserted into the hosel bore of the club head and attached thereto;

[0019] FIG. 4 is a sectional view as in FIG. 3 with the swing weight plug shown after the plug has been rotated about the longitudinal axis until a ridge and a spacer of the sleeve are positioned in the section plane;

[0020] FIG. 5 is a sectional view as seen along line 5-5 in FIG. 2 showing the uncompressed ridges of the sleeve;

[0021] FIG. 6 is a perspective view of another embodiment of a swing weight plug in accordance with the present invention in which the ridges extend helically on the outer surface of the sleeve and the swing weight plug has a hole to allow air to escape during assembly;

[0022] FIG. 7 is a perspective, exploded view of another embodiment of the present invention showing a portion of a club head having a pin, a swing weight plug and a portion of a golf club shaft;

[0023] FIG. 8 is a perspective view of yet another embodiment of the present invention in which the ridges of the sleeve are flap shaped;

[0024] FIG. 9 is an exploded, perspective view of a sleeve and high density material wherein the high density material is formed as bars;

[0025] FIG. 10 is an exploded, perspective view of a sleeve and high density material for another embodiment of the present invention wherein the high density material is formed as spheres;

[0026] FIG. 11 is an exploded, perspective view of a sleeve and high density material for another embodiment of the present invention wherein the high density material has a characteristic shape; and

[0027] FIG. 12 is a perspective view of still another embodiment of a swing weight plug in accordance with the present invention.

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, D.sub.1. Also, the shaft 16 defines an inner diameter, D.sub.2, 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, r.sub.3, measured from the axis 30 of the sleeve 20 to the radial extremity of each ridge 32. Accordingly, a corresponding diameter, D.sub.3, equal to 2.times.r.sub.3 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 D.sub.1<D.sub.2<D.sub.3. 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, D.sub.4. 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, D.sub.4 of the flange 40 is sized to be smaller than the diameter, D.sub.5 of the bore 38 of the golf club hosel 15, D.sub.4<D.sub.5 (note; the diameter, D.sub.5 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.

Claims

What is claimed is:

1. A plug assembly for increasing the swing weight of a golf club having a shaft, the shaft being hollow and having a first end and a second end, said plug assembly comprising: a sleeve for insertion into an end of said hollow shaft, said sleeve formed with a cavity; a high density material disposed in said cavity; and a means for attaching said sleeve to the shaft of the golf club for movement therewith.

2. A plug assembly as recited in claim 1 wherein said sleeve is formed with an inner wall surface surrounding said cavity and an outer wall surface, and wherein said attaching means comprises a plurality of ridges formed on said sleeve with each said ridge extending from said outer wall surface of said sleeve to contact said shaft and create an interference fit between said sleeve and said shaft to attach said sleeve to said shaft.

3. A plug assembly as recited in claim 2 wherein said sleeve is substantially cylindrically shaped and defines a longitudinal axis and wherein each said ridge is elongated and oriented on said outer wall surface with the direction of elongation substantially parallel to said longitudinal axis.

4. A plug assembly as recited in claim 2 wherein said sleeve is substantially cylindrically shaped and defines a longitudinal axis and wherein each said ridge extends substantially helically about said longitudinal axis on said outer wall surface.

5. A plug assembly as recited in claim 1 wherein said sleeve is formed with an inner wall surface surrounding said cavity and an outer wall surface, and wherein said attaching means comprises an adhesive material for bonding said outer wall surface of said sleeve to said shaft.

6. A plug assembly as recited in claim 1 wherein said sleeve is made of a plastic material.

7. A plug assembly as recited in claim 1 wherein said high-density material comprises a metal.

8. A plug assembly as recited in claim 1 wherein said high-density material is selected from the group consisting of Tungsten powder, sintered Tungsten rod, sintered Tungsten scrap parts, steel, stainless-steel, copper, brass, lead, and lead alloy.

9. A plug assembly as recited in claim 1 wherein said plug assembly weighs between approximately one gram (1 gm) and thirty grams (30 gms).

10. A golf club having a pre-selected swing weight, said golf club comprising: a head; a hollow golf shaft having a grip end and a head end; a sleeve for insertion into said head end of said hollow shaft, said sleeve formed with a cavity; a high density material disposed in said cavity; a means for attaching said sleeve to said shaft for movement therewith; and a means for affixing said head to said shaft at said shaft end.

11. A golf club as recited in claim 10 wherein said sleeve is substantially cylindrically shaped defining a longitudinal axis and is formed with an outer wall surface having diameter (D.sub.1), and wherein said shaft has an inner diameter (D.sub.2) at said head end, and further wherein said attaching means comprises a plurality of ridges formed on said sleeve with each said ridge extending from said outer wall surface of said sleeve to a ridge diameter (D.sub.3), and wherein said sleeve and said ridges are sized relative to said shaft with D.sub.1<D.sub.2<D- .sub.3 to create an interference fit between said sleeve and said shaft when said sleeve in inserted in said shaft and to allow air from said head to pass between said outer surface and said shaft after said sleeve is attached to said shaft.

12. A golf club as recited in claim 11 wherein each said ridge is elongated and oriented on said outer wall surface with the direction of elongation substantially parallel to said longitudinal axis.

13. A golf club as recited in claim 11 wherein said sleeve has a first end for insertion into said shaft and a second end, said sleeve being formed with a flange at said second end and having a plurality of spacers to maintain said flange at a preselected distance from said head end of said shaft after said sleeve is attached to said shaft.

14. A golf club as recited in claim 11 wherein said plurality of spacers are spaced apart around said sleeve and said flange is substantially cylindrical having a diameter (D.sub.4) and said head is formed with a hosel bore having a diameter (D.sub.5) with said flange sized relative to said hosel bore wherein D.sub.4<D.sub.5 to allow air from said head to pass around said flange, between said spacers and between said outer surface and said shaft during insertion of said shaft and said sleeve into said hosel bore.

15. A golf club as recited in claim 11 wherein said affixing means comprises a pin formed on said head for insertion into said head end of said shaft.

16. A method for preparing a golf club having a pre-selected swing weight, said method comprising the steps of: providing a head; providing a hollow golf shaft having a grip end and a head end; providing a sleeve formed with a cavity; disposing a high density material in said cavity; inserting said sleeve into said head end of said hollow shaft to attach said sleeve to said shaft for movement therewith; and affixing said head to said shaft at said shaft end.

17. A method as recited in claim 16 wherein said sleeve is formed with an inner wall surface surrounding said cavity and an outer wall surface, and wherein said sleeve is formed with a plurality of ridges with each said ridge extending from said outer wall surface of said sleeve to contact said shaft and create an interference fit between said sleeve and said shaft to attach said sleeve to said shaft.

18. A method as recited in claim 17 wherein said sleeve is substantially cylindrically shaped and defines a longitudinal axis and wherein each said ridge is elongated and oriented on said outer wall surface with the direction of elongation substantially parallel to said longitudinal axis.

19. A method as recited in claim 17 wherein said sleeve is substantially cylindrically shaped and defines a longitudinal axis and wherein each said ridge extends helically about said longitudinal axis on said outer wall surface.

20. A method as recited in claim 16 wherein said high-density material comprises Tungsten.

21. An assembly for increasing the swing weight of a golf club having a shaft, the shaft being hollow and having a first end and a second end, said plug assembly comprising: a plug for insertion into an end of said hollow shaft, said plug comprising a polymeric constituent having a density, .rho..sub.1, and a high density constituent having a density, .rho..sub.2, with .rho..sub.2>.rho..sub.1; and a means for attaching said plug to the shaft of the golf club for movement therewith.

22. An assembly as recited in claim 21 wherein said plug is made from a mixture comprising said polymeric constituent filled with said high density constituent.

23. An assembly as recited in claim 21 wherein said plug is made from a mixture of said polymeric constituent filled with secondary Tungsten powder having spheroidal grains.

24. An assembly as recited in claim 23 wherein said secondary Tungsten powder has a tap powder density between approximately ten grams per cubic centimeter (10 g/cc) and approximately twelve grams per cubic centimeter (12 g/cc).