Golf shaft flex connection

Abstract

A shaft insert (or external connecting segment) with greater flexibility than the substrate shaft allowing for a more flexible zone in an area of separation between two separated portions of the substrate shaft. The flexible connection is intended to be installed between two segments of the separated substrate shaft primarily on a golf putter with the flexible connection within 5 inches of the base of the club in total compliance with USGA (United States Golf Association) Rule 2, Appendix II. 2. b. requiring any change from the continuous shaft be within 5 inches of the club base. The shaft flex connection is designed to be symmetrical around its cross section with equal flexibility and torsional displacement in all directions in compliance with USGA Rule 2, Appendix 2. c. requiring golf shafts to be equally flexible with equal torsional displacement in all directions. The preferred embodiment of the invention utilizes a flexible tube for which the outside diameter is slightly smaller than the inside diameter of the substrate shaft. The substrate shaft is separated at the top of the hosel of the club and joined by fixing the tube (with epoxy or other adhesive) in each section of the separated sections of the substrate shaft whereby the separation is maintained at a fixed distance by installing an O ring or other spacer over the insert tube and between the two segments of the substrate shaft.

Claims

1. A Golf club comprising: A golf club head with a cylindrical insertion hole; a lower tubular shaft inserted into a distal end of said golf club head insertion hole and terminating flush with a top of said golf club head insertion hole whereby said lower tubular shaft is secured to said golf club head with adhesive; an upper tubular shaft with inside diameter and outside diameter corresponding to said lower shaft inside diameter and outside diameter; an flexible cylindrical insert with outside diameter essentially corresponding to the inside diameter of said upper tubular shaft and corresponding to the inside diameter of said lower tubular shaft inserted into a distal end of the upper tubular shaft and inserted into a distal end of said lower tubular shaft whereby said cylindrical insert is secured to said lower tubular shaft with adhesive and secured to said upper tubular shaft with adhesive; an flexible ring with inside diameter essentially corresponding with the outside diameter of said flexible cylindrical insert and outside diameter essentially corresponding with outside diameter of said lower shaft and said upper shaft whereby said flexible ring is place over the flexible cylindrical insert such that it is between the upper and lower tubular shafts and is in contact with said upper tubular shaft.

2. A golf club in accordance with claim 1, wherein said cylindrical insert is coaxial with said lower tubular shaft and said cylindrical insert is also coaxial with said upper tubular shaft such that said lower tubular shaft is coaxial with said upper tubular shaft.

3. A golf club in accordance with claim 1, wherein said flexible ring is helical.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) Preferred exemplary embodiments of the invention are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout, and in which:

(2) FIG. 1 is a sectional view of the conventional golf shaft with separation between the parts with insert and O ring installed.

(3) FIG. 2 is a sectional view of the rigid fitment of the lower portion of the shaft to the putter hosel with separation and O ring spacer just above the rigid fitment. The insert is also shown bridging the lower and upper portions of the separated shaft.

(4) FIG. 3 is a sectional view of the shaft and insert installation in the body of a putter without a hosel.

(5) FIG. 4 is a view of the shaft and insert installation in a putter head without hosel and with flex point above the putter body.

(6) FIG. 5 is a view of an alternate single piece flexible connection between two separated portions of a shaft.

(7) FIG. 6 is a sectional view of a flexible collar over the shaft sections providing the same functions as the insert

(8) FIG. 7 is a view of an alternate putter stem insert providing toe same putter face reaction as the shaft insert

(9) FIG. 8 is an amplified view of the preferred embodiment shown in FIG. 1 showing a more detailed view of the shaft sections as well as the epoxy or adhesive location. The O ring is not shown on one side of the gap between shaft sections for clarity.

(10) FIG. 9 is a modified free body diagram showing a right handed player side view of the preferred embodiment that shows the direction of displacement of the upper shaft section and resultant putter face displacement during the strike and resulting reaction of the golf ball.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(11) 1. Resum

(12) Pursuant to the preferred embodiment of the invention, a flexible shaft insert is composed of flexible nylon or other flexible tubing (or solid flexible shape) with an outside diameter matching or with clearance compared to the inside diameter of the substrate more rigid shaft. This insert is installed inside the shaft such that it bridges a separation between shaft portions which are separated by as little as 0.001 inch to any maximum distance that will provide the desired flexibility between the two portions of the substrate shaft. The separation in the substrate shaft is sized such that the lower portion of the shaft can be fixed inside the hosel or putter body with the separation occurring at the top of the hosel or putter body (depending on putter and shaft mounting design). At the top of the putter body or hosel, the O ring spacer (or alternate spacers) with an inside diameter matching the outside diameter of the flexible insert covering the space between the substrate shaft sections and resting on the putter body or top of the hosel. All connections are made between; insert and shaft segments, shaft and putter head or hosel, O ring or O rings and flexible insert using conventional cementing adhesive commonly used for such connections.

(13) 2. Construction and Operation of a First Preferred Embodiment and Possible Alternates

(14) Referring now to FIGS. 1-9 the exemplary putter illustrated in side view by FIG. 9 includes an upper shaft section 12, with lower section 11 inserted into hosel section 17 which is part of putter head 18 and shaft sections 11 and 12 connected by flexible shaft insert 13 with the fixed distance between shaft sections 11 and 12 fixed by flexible O ring (or alternate spacer) 15. The O ring 15 in FIG. 9 is shown in section but in fact is continuous around the circumference of the shaft and insert. The golfer holds and moves the putter at grip 33.

(15) Although the present invention is not limited to any particular putter configuration or golf club for that matter, the exemplary club shown is a putter with raised hosel on putter stem 19. The present invention is, however equally applicable to any golf club or putter configuration and not limited to shaft design or shaft or insert material.

(16) Turning to the insert assembly illustrated first by FIGS. 1 and 8, a golf shaft lower section 11 is separated from a golf shaft upper section 12 leaving a gap 16. Note that in FIG. 8 O ring 15 is not shown on one side for clarity to show gap 16. The shaft sections 11 and 12 are joined by flexible insert 13 and separated by O ring 15 installed over the gap 16. The flexible insert 13 is fixed to the shaft surface at points of contact by epoxy or other adhesive 14. The O ring 15 is also fixed to the exposed surface of the insert 13 at the controlled gap 16 with epoxy or other adhesive 14.

(17) As illustrated by FIG. 2, the lower section of the golf shaft 11 is installed into the hosel 17 using adhesive 14 with O ring 15 resting on top of hosel 17.

(18) As illustrated by FIG. 3, alternately the shaft lower section 11 is shown in putter body 18 using adhesive 14 with gap 16 coincident with O ring 15 resting on top of putter body 18 which is an illustrated connection method for putters without a raised hosel.

(19) FIG. 4 shows an alternate for accommodating a third type of popular putter connection, with coincidental separation and O ring 15 and 16 oriented above putter head 18. The insert 13 and lower shaft section 11 can be installed over putter stem 30 which is either located within the putter head 18 or as an extension of the putter head 18. Optional non flexible collar 20 is fixed below O ring 15 and in contact with bottom of O ring 15 if additional stability in flex and torsional control is required. All points are secured with adhesive 14.

(20) While many alternates to the preferred embodiment of the invention are possible, FIG. 5 illustrates a first alternate to the preferred embodiment of the invention shown by alternate insert 21 which is single molded piece integrating a collar 22 which replaces the O ring 15 of the first preferred embodiment. All portions are attached to lower shaft section 11 and upper shaft section 12 with adhesive 14. While the sectional view of alternate insert 21 shows the insert as solid it can also be hollow.

(21) Another possible alternate to the preferred embodiment of the invention which retains the same principle of allowing added flexibility between shaft sections is shown by FIG. 6 demonstrating an outside flexible collar 23 with integrated or separate spacer 24 separating shaft lower section 11 and shaft upper section 12 with all surfaces in contact with shaft section 11 and shaft section 12 secured with epoxy or other adhesive 14.

(22) The principle of the invention is not limited to adding a point of increased flexibility to the shaft. As illustrated by FIG. 7, similar flexible sections can be integrated into the putter head as exemplified by the flexible stem insert 25 inserted between two separate sections of putter stem 19 that connects hosel 17 and putter body 18.

(23) Returning to FIG. 9, the principle of the invention is illustrated by this modified free body diagram whereby when the putter is moved in positive direction 31 initiating contact with stationary golf ball 28, the following reactions take place:

(24) Inertial resistance of the stationary golf ball 2B results in coincidental deflection of flexible connection 13 by variable angle .

(25) The result of the deflection angle caused by the resisting inertia of the golf ball and the force of the strike by putter head 18, is a coincidental deflection of the putter head along variable camber angle B.

(26) Due to the creation of camber angle B by the added flexibility of insert 13, tangential force vector 26 is created which imparts improved roll to the golf ball 28.

(27) In the absence of camber angle B during the strike by putter head 18, only force vector 27 exists which is resisted by the frictional force vector 32 between the golf ball 28 and the putting surface resulting in the tendency of the golf ball to become airborne thus resulting in a skipping action that reduces accuracy of the putt.

(28) Of course, many modifications could be made to the invention as described and illustrated without departing from the spirit of the present invention. The scope of such changes will become apparent from the appended claims.