WEIGHT SECURED BY EXPANSION ELEMENT IN GOLF CLUB SHAFT

Abstract

A golf club counter-weighting system, viable for both original manufacture and after-marketing, features an expandable weight assembly that is easily installed at a designated location within a golf club shaft and expanded via a user tool so as to become reliably secured in place by frictional pressure against the surrounding shaft. In a primary embodiment, the weight assembly is made to be threadedly engagable by the opposite end of a dual-function user tool enabling the weight assembly, when unexpanded, to be conveniently moved axially for initial installation, relocation and/or removal.

Claims

1. A golf club weighting system for adding a desired amount of swing weight at a designated axial location in a hollow shaft of a golf club equipped with a grip, the system being viable in original manufacture, in after-marketing and in user golf play, implemented by a weight assembly comprising: a cylindrical rigid weight element, located coaxially in the hollow shaft, having an outside diameter made smaller than the shaft's inside diameter so as to provide a designated inherent peripheral clearance therebetween; a cylindrical expansion element, located coaxially in the hollow shaft beneath said weight element and attached thereto, having an inherent unexpanded outside diameter made smaller than the shaft's inside diameter so as to provide a designated inherent peripheral clearance dimension therebetween whenever said expansion element remains unexpanded; and an expansion subsystem in said weight assembly, including a machine screw that is drivable by a user expansion tool to clamp said resilient expansion element against said weight element so as to causing axial compression in said expansion element that translates into radial expansion exerting compressive contact against the surrounding shaft, thus applying thereto a frictional force that that can be increased by the user until said weight assembly becomes positively and reliably secured in place by frictional pressure against the surrounding shaft, thus ensuring fully satisfactory golf play with a desired amount of swing-weight added at the designated axial location.

2. The golf club weighting system as defined in claim 1 wherein said expansion subsystem comprises: said weight element being configured with (a) a coaxial bore having a threaded upper portion and a lower portion with reduced diameter, forming a co-axial ledge therebetween, and (b) a tubular-shaped resilient foam sleeve surrounding said weight element and held continuously compressed in contact with the surrounding shaft; said expansion element being configured with a coaxial bore and fitted at bottom with a pressure plate having a threaded central opening; the machine screw having a screw-head configured with a central driving recess, the screw-head located in the bore of said weight element, seated on the coaxial ledge with a threaded part of the machine screw extending downwardly, through the smaller diameter lower portion of the bore, continuing through the bore of said expansion element and engaging the threaded opening of the pressure plate, whereby tightening the screw clockwise acts to clamp and compress the resilient expansion element between said weight element and said pressure plate causing axial compression in said expansion element that translates into radial expansion exerting compressive contact against the surrounding shaft to frictionally secure said weight assembly in place in the shaft for golf play.

3. The golf club weighting system as defined in claim 2 further comprising a user expansion tool made with a driving end configured to engage and rotate the screw for purposes of deploying expansion of said expansion element so as to secure said weight assembly in place in the shaft by rotating said user expansion tool clockwise and to release the expansion by rotating said user expansion tool counterclockwise.

4. The golf club weighting system as defined in claim 3 further comprising a user location tool being configured with a threaded engagement end made to threadedly engage the threaded bore portion in the weight element, whereby the user is enabled to threadedly attach the tool to the weight assembly and manipulate said user location tool in a manner to displace said weight assembly axially in the shaft for purposes of installing, relocating and removing said weight assembly.

5. The golf club weighting system as defined in claim 4 wherein the tubular-shaped resilient foam sleeve surrounding said weight element is continuously compressed in contact with the surrounding shaft with sufficient friction to retain said weight assembly in place in the shaft whenever said expansion element is unexpanded and to prevent rotation thereof when the screw is being rotated for expansion and release, yet allowing said weight assembly to be displaced axially in the shaft using said user location tool for purposes of installing, relocating and removing said weight assembly.

6. The golf club weighting system as defined in claim 5 wherein the central driving recess in the screw-head and the driving end of said user expansion tool are made hexagonal in cross-sectional shape.

7. The golf club weighting system as defined in claim 5 further comprising: an externally threaded grip cap threadedly attached to the grip; and a central though-opening in said cap, configured in a standard hex drive cross-sectional shape for purposes of attachment and removal of the cap portion relative to the grip, said though-opening being made sufficiently large to allow insertion of the screw-driving end of said user expansion tool for purposes of securing and releasing the weighting assembly relative to the shaft.

8. The golf club weighting system as defined in claim 2 in an embodiment thereof wherein the designated axial location in the upright hollow shaft of the golf club is at an uppermost top portion thereof.

9. The golf club weighting system as defined in claim 8 wherein said weight assembly further comprises a grip cap, attached onto a top portion of the weight element, configured with a central though-opening sufficiently large to allow insertion of the screw-driving end of said user tool.

10. The golf club weighting system as defined in claim 9 further comprising: said grip cap being externally threaded and thereby threadedly attached to the grip; and the central though-opening in said cap being configured in a standard hex drive cross-sectional shape for engagement with a standard hex drive tool for purposes of rotating said cap portion along with the attached unexpanded weight assembly for threaded attachment thereof to the grip, and for detachment therefrom.

11. The golf club weighting system as defined in claim 8 wherein said weight assembly further comprises the weight element being configured to further include, in an uppermost region thereof, a grip cap portion configured with a central though-opening sufficiently large to allow insertion of said user location tool for purposes of securing and releasing the weighting assembly relative to the shaft.

12. The golf club weighting system as defined in claim 11 further comprising: the grip cap portion being externally threaded and thereby threadedly attached to the grip; and the central though-opening in the cap portion being configured in a standard hex drive cross-sectional shape for engagement with a standard hex drive tool for purposes of rotating the unexpanded weight assembly via the cap portion thereof for threaded attachment thereof to the grip, and for detachment therefrom.

13. A method of adding swing weight to be frictionally secured in place at a designated location in a hollow shaft of a golf club, viable in original manufacture, in after-marketing and in user golf play, comprising the steps of: (a) attaching a location tool to a weight assembly comprising a weight element held together against an unexpanded resilient expansion element by a machine screw with a screw-head made drivable by an expansion tool; (b) deploying the location tool to insert the weight assembly to a designated location in the shaft; (c) detaching and withdrawing the location tool from the shaft; (d) inserting the expansion tool into the shaft and into driving engagement with the screw-head; (e) rotating the screw clockwise by the expansion tool to pressurize and expand the expansion element so as to apply increasing pressure force peripherally against the surrounding shaft until the weight assembly has been frictionally secured in place; and (f) withdrawing the expansion tool from the shaft.

14. The method of claim 13 continued to later move the weight assembly to another location in the shaft, comprising the further steps of: (g) inserting the expansion tool into the shaft and into driving engagement with the screw-head; (h) rotating the screw counterclockwise by the expansion tool to depressurize and release the expansion element from contact with the shaft; (i) withdrawing the expansion tool from the shaft; (j) inserting the location tool into the shaft and engaging the weight element; (k) moving the weight assembly to the different location in the shaft by manipulation of the location tool; (l) withdrawing the location tool from the shaft; (m) inserting the expansion tool into the shaft and into driving engagement with the screw-head; (n) rotating the screw clockwise by the expansion tool to pressurize and expand the expansion element so as to secure the weight assembly in place in the different location; and (o) withdrawing the expansion tool from the golf club.

15. The method of claim 13 continued to later remove the weight assembly from the golf club, comprising the further steps of: (p) inserting the expansion tool into the shaft and into driving engagement with the screw-head; (q) rotating the screw counterclockwise by the expansion tool sufficiently to depressurize and release the expansion element from contact with the shaft; (r) withdrawing and removing the expansion tool from the golf club; (s) inserting the location tool into the shaft and engaging the weight element; and (t) removing the weight assembly from the golf club shaft by manipulation of the location tool.

16. A method of adding a weight assembly within a hollow shaft of a grip-equipped golf club at a designated location restricted to an uppermost portion of the shaft, secured in place by the combination of (1) an expansion element capable of frictionally engaging the shaft and (2) a cap portion atop the weight assembly, threadedly engaging the grip, viable in original manufacture, in after-marketing and in user golf play, comprising the steps of: (a) configuring the weight assembly including a cylindrical weight element, smaller in diameter than the shaft interior, combined with an overhead externally-threaded annular grip cap portion larger in diameter than the weight element, and an underlying resilient expansion element, deployable via a screw-head made accessible and engagable by a user expansion tool to be expanded radially so as to frictionally secure the weight assembly in place in the shaft; (b) configuring the grip with a top central grip opening sized and internally threaded to engage the cap portion; (c) inserting the weight assembly, unexpanded, through the grip [opening into the top of the shaft, until the cap portion is aligned for threaded attachment to the grip; (d) inserting a cap drive tool into engagement with a driving recess in the cap portion; (e) rotating the weight assembly, by the cap drive tool, to thread the cap portion fully into the grip thus placing the weight assembly in the designated uppermost location in the shaft; (f) removing the cap drive tool from the golf club; (g) inserting the expansion tool into engagement with the screw-head; (h) rotating the expansion tool and screw-head clockwise until the expansion element displaces the weight assembly axially in the shaft for purposes of installing, relocating and removing the weight assembly; and (i) removing the expansion tool from the golf club.

17. The method of claim 16 continued to later remove the weight assembly from the golf club, comprising the further steps of: (j) inserting the expansion tool into engagement with the screw-head; (k) rotating the expansion tool and screw counterclockwise so as to relax the expansion element until the weight assembly becomes released from contact with the shaft; (l) removing the expansion tool from the golf club; (m) engaging the cap portion with the cap drive tool and rotating the weight assembly thereby so as to unthread the cap portion fully from the grip thus releasing the weight assembly from the grip; (o) removing the cap drive tool from the golf club; (p) removing the weight assembly from the golf club; and (q) restoring the grip to a playable condition including closure of the grip opening.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and further objects, features and advantages of the present invention will be more fully understood from the following description taken with the accompanying drawings in which:

[0017] FIG. 1 is a cross-sectional elevation of an upper portion of a grip and shaft of a golf club equipped with a weight assembly of the present invention.

[0018] FIG. 2 is an enlargement of a portion of FIG. 1 showing an expansion element frictionally securing the weight assembly to the surrounding shaft portion.

[0019] FIG. 3 is an elevational view of a dual-function tool for (1) securing/releasing the weight assembly of FIGS. 1 and 2 relative to the shaft and (2) vertical displacement of the weight assembly for installation, relocation and/or removal thereof.

[0020] FIG. 4 depicts the items shown cross-sectioned in FIG. 1 with the addition of the tool of FIG. 3 engaging the expansion mechanism, shown expanded, securing the weight assembly to the shaft.

[0021] FIG. 5 shows the items of FIG. 4 with the tool inverted and threadedly engaging the weight element for insertion, repositioning or removal of the weight assembly.

[0022] FIG. 6 is an enlarged cross-sectional view of an alternative embodiment of the invention wherein the weight assembly includes an attached custom grip cap.

[0023] FIG. 7 is a top view of the grip cap of FIG. 6.

[0024] FIG. 8 depicts a single-function tool configured with a hex driver end for deploying/releasing expansion of the weight assembly of FIG. 6.

[0025] FIG. 9 depicts the items shown cross-sectioned in FIG. 6 with the addition of the tool of FIG. 8 engaging the expansion mechanism, shown expanded, securing the weight assembly at the designated location at the top end region of the shaft.

DETAILED DESCRIPTION

[0026] FIG. 1 is a cross-sectional elevation of an upper portion of a golf club having a grip 10 fitted onto a shaft 12 within which a weight assembly 14 of the present invention has been installed and secured at the selected axial location shown. A removable cap 16 in the top of grip 10 is fitted into a central opening in grip 10 sized to allow insertion and installation of weight assembly 14. Typically cap 16 is configured at top center with a driving recess and traversed there by a small vent passageway as shown.

[0027] FIG. 2 is an enlargement of a portion of FIG. 1 showing a resilient expansion element 20 expanded and thus frictionally securing the weight assembly 14 to the surrounding portion of shaft 12. In weight assembly 14, a metal weight element 18 is coupled onto and drawn against expansion element 20 by a machine screw 22 threadedly engaging an annular pressure plate 24, in the form of an inverted T-nut, bearing against the bottom side of expansion element 20. As shown, screw 22 has been tightened to compress the resilient expansion element 20 axially, causing it to expand radially against the interior surface of shaft 12 so as to secure the weight assembly 14 in place at the desired axial working location.

[0028] A foam sleeve 26 surrounding weight element, and typically attached thereto adhesively, is made and dimensioned to hold the weight assembly 14 concentric in shaft 12 at all times, continuously applying a designated relatively low amount of frictional pressure against the surrounding internal surface of shaft 12.

[0029] Foam sleeve 26 is designed and dimensioned to deliver a particular designated amount of frictional pressure radially onto surrounding shaft 12 such that, with expansion element 20 disengaged from shaft 12, the friction is (1) sufficiently high enough to hold weight assembly 14 in place in shaft 12 without rotation while screw 22 is being rotated by driver tool end 28A to deploy/release expansion element 20, and yet (b) sufficiently low enough to allow convenient axial displacement of weight assembly 14 for relocation or removal by user manipulation of tool 28, engaged by threaded driver end 28B as shown in FIG. 5.

[0030] FIG. 3 is an elevational view of a dual-function tool 28 configured with (1) a hex driver end 28A at the lower end as shown, for securing/releasing the weight assembly 14 of FIGS. 1, 2, 4 and 5 relative to the shaft 12, and (2) an externally threaded end portion 28B at the opposite upper end for engaging weight element 18 (FIG. 2) to enable user manipulation of axial displacement of weight assembly 14 for installation, relocation and/or removal thereof, subsequent to releasing expansion element 20 from shaft 12 utilizing hex driver end 28A as shown in FIG. 4.

[0031] FIG. 4 depicts the items cross-sectioned in FIG. 1 with the addition of the hex tool end 28A of tool 28 of FIG. 3 inserted into the bore of weight element 18 and engaging a hex drive recess configured in the head of screw 22, seated on the lower portion of weight element 18. The resilient expansion element 20 is shown as having been released from engagement with shaft 12 by the user rotating tool 28 counter-clockwise to reduce the axial compressive pressure in expansion element 20 until its diameter is reduced sufficiently to disengage from shaft 12, leaving the weight assembly 14 retained in place only by the relatively low radial compressive frictional force from the foam sleeve 26 acting on the surrounding shaft 12, thus facilitating relocation or removal of the weight assembly 14 by user-manipulation of tool 28.

[0032] FIG. 5 shows the items of FIG. 4 with tool 28 having been inverted and its threaded end portion 28B positively engaging the upper threaded portion of the bore of weight element 18. Since the expansion element 20 is disengaged from shaft 12, as described above in connection with FIG. 4, vertical displacements of weight assembly 14 for purposes of installation, relocation and removal thereof, are readily accomplished by user-manipulation of tool 28.

[0033] For installation in original manufacture, aftermarketing and user golf play, weight assembly 14 is initially pre-set to its inherent unexpanded condition by counterclockwise rotation of the tool 28 with its hex driver end 28A engaging screw 22. Then tool 28 is inverted and with end 28B threaded into weight element 18, the weight assembly 14 is inserted into the shaft 12 to the desired location, unexpanded as shown in FIG. 5. Then weight assembly 14 is secured in place by inverting tool 28, engaging screw 22 with hex end 28A and rotating tool 28 clockwise to expand the expansion element 20 against shaft 12 until the weight assembly 14 becomes firmly secured in place as shown in FIG. 2. Then, with tool 28 removed and cap 16 (FIG. 1) replaced, the weighted golf club is ready for play.

[0034] For removal or relocation of weight assembly 14, cap 16 (or grip 10) is removed, and tool end 28A is inserted and engaged into screw 22, as shown in FIG. 4, then rotated counterclockwise until expansion element 20 disengages from shaft 12. Then tool 28 is withdrawn, inverted, inserted and rotated clockwise to thread end 28B into weight element 18, whereupon the weight assembly 14 can then be easily and reliably removed or else relocated and secured in place as described above; then as before, with tool 28 removed and cap 16 (FIG. 1) (or grip 10) put back in place, the weighted golf club is ready for play.

[0035] Optionally, the low end of screw 22 can be swaged or crimped as shown in FIG. 6 in order to prevent unintentional unthreading and separation of T-nut pressure plate 24, thus rendering the weight assembly 14 as an integrated module of which the component parts are not readily separable.

[0036] Optionally, two or more weight assemblies 14 could be installed, as described above, at designated locations in shaft 12, subject to making tool 28 sufficiently long.

[0037] In the primary embodiment of the invention, cap 16 (FIG. 1) plays no significant role apart from cosmetically filling an access opening in the grip 10 that may be provided as an optional alternative to utilizing a standard grip that would require removal to allow access for installation or removal of a weight assembly.

[0038] The range of available working locations of weight assembly 14, extending downward from the top end of shaft 12, is limited by the length of tool 28, typically made approximately 12 inches long, as considered to be adequate for practically all weighting requirements.

[0039] FIG. 6 is an enlarged cross-sectional view of a secondary embodiment of the invention, wherein a weight assembly 14, as described above in the primary embodiment, has been modified by addition of an adhesively-attached custom grip cap 16′ and omission of foam sleeve 26 (FIGS. 4 and 5) to form a modified weight assembly 14′ representing the secondary embodiment distinguished by (a) providing coaxial integrity that holds the weight element 18 centered in shaft 12 and allows elimination of foam sleeve 26 (FIG. 4), (b) being restricted to a single designated working location at the uppermost end region of shaft 12, and (c) thus eliminating need for tool end driver 28B and for the internal threading in the upper portion of the bore of weight element 18.

[0040] Cap 16′ is configured with (a) an externally threaded main portion, as shown, for threaded attachment to the grip 10, (b) a central opening 16A with hex cross-sectional shape (FIG. 8) serving as a driving recess for cap-rotation driven by a standard hex driver tool, and (c) central opening 16A traverses cap 16′ in hex cross-sectional shape serving to provide ample clearance for insertion of the hex driver end 28A of tool 28 for engaging screw 22 as shown in FIGS. 4 and 9.

[0041] FIG. 7 is a top view of cap 16′ of FIG. 6 showing the hex cross-sectional shape of central opening 16A described above in connection with FIG. 6.

[0042] FIG. 8 depicts a single-function tool 28′ configured with a hex driver end 28A for engaging machine screw 22, as described in connection with FIGS. 3 and 9, to deploy and release expansion of expansion element 20 of weight assembly 14′ (FIG. 6).

[0043] FIG. 9 depicts the modified weight assembly 14′ of FIG. 6, the secondary embodiment, containing the items shown cross-sectioned in FIG. 6 along with the addition of the single-function (expansion) tool 28′ of FIG. 8 with hex driver end 28A temporarily remaining engaged with machine screw 22 after having expanded the expansion element 20 as shown, securing the weight assembly 14′ at its designated location: the uppermost top end region of the shaft 12.

[0044] In the secondary embodiment weight assembly 14′, the approach of adding cap 16′ adhesively attached onto weight element 18, as shown in FIGS. 6 and 9, was a design choice predicated on the special circumstance of anticipation that the primary embodiment weight assembly 14 would be already in production and thus readily available as an adaptable complete assembly or kit of already tooled and existing available component parts, to serve beneficially as the predominant main basis of the second embodiment weight assembly 14′, requiring only the addition of custom cap 16′, adhesively attached. Sleeve 26, no longer required, could optionally be omitted or left in place. Another advantage of this approach of attaching cap 16′ onto weight element 18 is that these may be made from different optimally-selected materials, e.g. aluminum and brass respectively.

[0045] As an alternative to attaching cap 16′ to weight element 18, these can be combined into a single component designed to serve as an integrated cap/weight element that is fully equivalent functionally, more rugged structurally, and potentially cost effective, considering the elimination of costs and labor associated with sleeve 26, and eliminating the machining of threading inside the weight element, no longer required due to the designated location of the weight assembly being restricted to the uppermost end region of shaft 12.

[0046] The invention can be practiced with materials, details, sizes and proportions of the component parts deviating from those indicated in the drawings of the illustrative embodiments shown. Tools and mating drive receptacles shown and described as hex could optionally be implemented in any other equivalent driver configuration.

[0047] This invention may be embodied and practiced in other specific forms without departing from the spirit and essential characteristics thereof. The present embodiments therefore are considered in all respects as illustrative and not restrictive. The scope of the invention is indicated by the appended claims rather than by the foregoing description. All variations, substitutions, and changes that come within the meaning and range of equivalency of the claims therefore are intended to be embraced therein.