AU8051491A

AU8051491A - Golf club handle

Info

Publication number: AU8051491A
Application number: AU80514/91A
Authority: AU
Inventors: Dennis Livesey
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-06-18
Filing date: 1991-06-13
Publication date: 1992-01-07
Also published as: FI925540A; EP0535079A1; WO1991019544A1; EP0535079A4; CA2084752A1; FI925540A0

Description

GOLF CLUB HANDLE 5

Technical Field

This invention relates to golf clubs and more * particularly to a grip for a golf club handle and method of 10 manufacture.

Background Art As known, golf clubs are classified as woods and irons with each club having a club head supported at one end of a shaft with a gripping surface provided at the other end

15 of the shaft. This gripping surface usually comprises a strip of leather or other material wrapped around and along the handle end of the shaft of the golf club to a predetermined point approximately ten inches along the length of the shaft where it is secured. 0 These wrappings in time become loose and separate one turn from another along the club shaft and unless repaired, the golf club becomes useless.

Another prior art structure forms a slip on cylindrical sleeve usually formed of rubber including a 5 varying mixture of cork and rubber, cord and rubber, and silicone. This type of gripping surface in time wears and loses its tacky feeling, i.e., it becomes slick and shiney after very limited use.

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Moreover, separately molded caps secured by various 0 means to the butt end of separately molded sleeve type golf grips frequently become detached in use thereby rendering the golf club undesirable for continued use. Further, the prior art gripping surfaces may have excessive weight variations and are not consistently manufactured to provide a weight stability of less than two grams as accomplished by the process disclosed herein. Accordingly, a need exists for a new gripping surface for golf clubs and one that particularly simulates a newly wrapped natural leather surface that maintains over a long period of time the natural tacky feeling of leather regardless of weather conditions. Prior to the present invention, the majority of molded golf club grips were made of a tacky material and were molded in so-called book molds. A book mold is a horizontal mold consisting of a lower half and an upper half. The upper half is usually hinged to the lower half and the mold is opened by lifting the upper half as in opening a book. Hence, the name "book mold". One of the significant disadvantages of a book mold is that there is a visible ridge ("flashing lines") around the midpoint of the molded product comprising the excess material squeezed out of the mold during the molding process. The flashing lines are undesirable and must be removed before the product is sent to market. When the mold is opened, the internal pressure theretofore applied by the mold cavity walls through the mold material to the core pin in the central bore of the molded product is released. The central pin in the book mold has a uniform diameter and provides a corresponding central bore of uniform diameter in the molded part. Upon release of the pressure as described above, the core pin is easily withdrawn horizontally from the molded part without stretching or damaging the molded part.

The introduction of vertical molding and the use in the present invention of a special type cavity mold has

5 introduced the need to vertically remove the core pin from the

* cavity of the mold with pressure still applied to the core pin through the mold material which has presented the problem of stretching or damaging the molded part as a core pin of uniform diameter is withdrawn due to the extended length of

10 the sleeve type grip and the very tacky quality of the material. This problem is aggravated when the cap portion of the grip is molded integrally with the body of the grip requiring the core pin to be withdrawn from the one open end of the grip.

15 Thus, a need exists for an improved molding process that permits efficiently molding body and cap in a single operation while allowing the core pin to be vertically withdrawn without stretching or damaging the molded part.

Disclosure Of Invention 0 It is, therefore, one object of this invention to provide a new and novel gripping surface for the shaft of a golf club.

Another object of this invention is to provide a molded gripping surface which may be telescopically fitted 5 over the free end of the shaft of a golf club that provides

_* over a long period of time under various climate conditions the natural tacky feeling of a newly wrapped leather gripping surface. - A further object of this invention is to provide a resilient, tapered, molded grip that may be telescopically fitted over the free end of a golf club shaft which provides a tacky feeling gripping surface for the golfer. A still further object of this invention is to pro¬ vide a new method for manufacturing a gripping surface for the shaft of a golf club.

It is a further object of this invention to provide a new vertical molding method for manufacturing an integral cap and gripping surface for the shaft of a golf club wherein the method utilizes a unitary cast cavity mold the core pin of which is tapered with an increasing diameter from the wide butt end to the narrow open end of the molded gripping surface. Other objects and advantages of the invention will become apparent from the following description when considered in conjunction with the accompanying drawing.

To achieve the foregoing objects in accordance with the purposes of the present invention, as embodied and broadly described herein, one aspect of the invention is a grip for the shaft of a golf club and the method of making the same which includes molding an elongated, hollow, resilient body the exterior surface of which is tapered, a cap covering the wider end of the body and a collar at the narrower end, and the central opening or hollow of which is adapted to contact the golf club shaft and is tapered with a decreasing diameter extending from the narrower open end to the wider closed end of the body, e.g.. a reverse taper. Another aspect of the present invention is to form the exterior surface to simulate a wrapped strip configuration.

Another aspect of the present invention is to form the cap integrally with a body having a repetitive stippling ornamentation.

A further feature of the present invention is the extended wear resistance and retention of the tacky quality over a longer period of time than natural leather under all weather conditions.

Brief Description of the Drawings The present invention may be more readily described with reference to the accompanying drawing, in which:

Fig. 1 is a perspective view of a grip for the handle of a golf club (not shown).

Fig. 2 is a cross sectional view of Fig. 1 taken along the line 2-2;

Fig. 3 is a cross sectional view of Fig. 1 taken along the line 3-3; Fig. 4 is a cross sectional view of Fig. 1 taken along the line 4-4 and shows the reverse taper on the walls of the interior opening which contacts the golf club shaft in accordance with the present invention;

Fig. 5 is a partial view of Fig. 1 showing the ornamental design of the surface of the grip;

Fig. 6 is a modification of the surface design shown in Fig. 6; and Fig. 7 is a cross sectional view of Fig. 5 taken along the line 7-7.

Best Mode For Carrying Out the Invention Referring more particularly to the drawing by characters of reference, Figs. 1 through 4 disclose a grip 10 for the shaft of a golf club (not shown) which comprises a monolithic, hollow, molded, tapered configuration. The hollow interior 11 is adapted to receive and contact the shaft of a golf club with the free end of the shaft of a golf club being positioned inside the grip juxtapositioned to the cap or closed end 12 of the grip. As shown in Fig. 4, the hollow interior 11 is outwardly tapered with a decreasing diameter extending from the narrow end 16 to the wide end 14 of the body 13. Thus, hollow interior 11 has a reverse taper relative to the outer surface 15 of the body 13.

As shown in Fig. 4, the cap or closed end 12 of the grip is preferably molded to body 13 of grip 10. Alternatively, it may comprise a separate part suitably secured to end 14 of grip 10 and still fall within the scope of this invention.

Figs. 1 and 4 illustrate that the outer surface 15 of grip 10 may be molded to simulate a cloth or leather wrapped surface with the wrapping starting at the end 14 of the grip and progressing to end 16 of the grip at which point it terminates in a collar 17.

Surface 15 of the grip may have any further orna¬ mentation such as the imitation stippling configuration shown at 18 in Figs. 1 and 5. - Fig. 6 illustrates a modification of the stippling design shown in Figs. 1 and 5 wherein the imitation stipplings 20 are shown in a circular configuration with a further imitation stippling 21 shown at the center of the circular design.

It should be noted that the material of grip 10 should be resilient enough for the golfer when gripping it to feel the comfort of a tight, tacky non slip grip.

Industrial Applicability In the present invention I use a vertical injection molding process with a unitary cast cavity mold. In the vertical injection molding process used to mold grips according to my invention, the cast cavity does not open as does the book mold known in the prior art. In my molding process the central pin which molds the central opening of the part is withdrawn downwardly from the mold after the part has been molded but while the molded part still remains in the cast cavity. In this condition, pressure is still applied by the walls of the cast mold through the rubber in the cavity to the core pin. If the core pin has a common diameter as is known in the prior art, or, even worse, if it has a taper which parallels the taper of the exterior surface 15 of the grip 10, it is extremely difficult to withdraw the pin downwardly without distorting or damaging the molded part. However, with a reverse taper on the core pin, e.g., an increasing diameter from the wide butt end 14 of the part 10 to the narrow open end 16 of the part 10, the core pin is easily downwardly withdrawn notwithstanding the very tacky quality of the resilient material from which the part 10 was molde .

Because of the reverse taper on the core pin as a result of my vertical injection molding process, the inside diameter ("ID") of the grip 10 at its narrow open end 16 is typically smaller than the outside diameter ("OD") of the shaft at the butt end of the shaft and is equal to or smaller than the OD of the shaft at a point about ten (10) inches down the shaft. Also, the reverse taper on the inner surface of the golf grip is opposite in direction to the taper on the standard golf club shaft which is wide at the butt end and progressively narrower toward the club head end of the shaft. The task is to insert the shaft with its thickest end first entering into the increasingly narrowing opening in the grip such that the shaft bottoms out ("home") against the inner end of the butt end of the grip without damaging the grip while at the same time the narrow end of the grip resiliently contracts to snugly grip the lower end of the shaft upon completion of the insertion. As is well known, an assembled grip must have a solid firm contact of the central bore of the grip throughout its length on the contiguous part of the shaft over which it is inserted.

This problem is solved first by choosing the right amount of taper on the inner opening prior to molding. As is well known, the ID of the grip at its narrow open end is preferably equal to or smaller than the OD of the golf club shaft at a point about ten (10) inches down the shaft from the butt end of the shaft. I prefer a taper of about seven thousandths of an inch (.007") over the approximate ten (10) inch length of a standard grip. When the amount of taper approaches twenty-five thousandths of an inch (.025"), there

a may be difficulty in getting the grip fully "home" on the

5 shaft, and there is a risk of splitting the grip at its butt end upon full insertion on the shaft. When the amount of taper approaches fifty thousandths of an inch (.050"), even if the grip does not split, there is the additional problem of the grip feeling uncomfortably fat in the hands of the golfer.

10 Thereafter, given a proper amount of taper as aforesaid, and a standard tapered club with an OD of about .580 inches at its butt end and approximately .555 inches at a point ten (10) inches down the shaft, the assembly is quite easily achieved due to the resilient nature of the rubber

15 material of the grip. Even with a very wide club having a dimension of .620 inches at the butt end, the grip may still be slipped over the shaft due to the grip's resilient nature. Once the narrow open end of the grip is stretched over the butt end of the shaft slightly, it is also known to use an

20 air source to inflate the grip through a hole in the butt end thereof to assist in moving the grip to a fully inserted position on the shaft.

Finally, given a proper amount of taper as aforesaid, even when a doubly adhesive tape is used on the

25 portion of the golf club shaft covered by the grip for the

• purpose of securing the grip to the shaft to prevent slippage in the golfer's hand during the swing, the solution to the problem described above is easily accomplished. For example, the assembly is accomplished by applying a doubly-adhesive tape around the shaft, applying a solvent to the adhesive which makes it gooey, applying the solvent to the inner opening of the grip to lubricate the grip and then slipping the grip over the tapered shaft until it is fully "home" and allowing it to set.

Notwithstanding these problems with the vertical molding process, the solutions described above are cost effective and the benefits of a vertical molding process using a unitary cast cavity mold, on balance, make the process more desirable than the older, book mold technology.

Although but a few embodiments of the invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the in¬ vention or from the scope of the appended claims.

Claims

What is claimed is:

1. A grip for the shaft of a golf club having an elongated, hollow, tapered body formed of a resilient molded material, 5 a collar formed at the narrow end of the body

*> simulating the termination of the wrapping of the strip of material, and a cap covering the wider end of the body, characterized by: 10 the hollow interior of the body adapted to contact the shaft outwardly tapering with a decreasing diameter from the narrower end to the wider end of the body.

2. The grip set forth in claim 1 further characterized by:

15 the outside surface of said body being formed to simulate a strip progressively wrapped around and along at least a portion of the length of the shaft of a golf club.

3. The grip set forth in claim 1 further characterized in that:

20 the cap is formed integral by with the body of the grip.

4. The grip set forth in claim 1 further characterized in that:

♦ the outer surface of said body is provided with

25 a repetitive design forming a simulated stippling ornamentation. 5. The grip set forth in claim 1 further characterized by: said resilient material including a rubber material which maintains the natural tacky feeling of newly wrapped leather regardless of weather conditions.

6. The grip set forth in claim 5 further characterized in that: the natural tacky feeling is retained over a longer period of time than newly wrapped leather.

7. The grip set forth in claim 1 further characterized in that: the durability and wear resistance of the grip exceeds that of natural leather.

8. A method of forming a grip for a shaft of a golf club according to claim 1 comprising the steps of: molding an elongated body of a resilient material having a tapered exterior surface and a central opening adapted to contact the shaft, and forming the body to simulate a cap covering its wider end and a collar at its narrower end characterized by: tapering the central opening with a deceasing interior diameter from the narrower end to the wider end of the body.

9. The method of claim 8 further characterized by: molding the body with the outer surface simulating a wrapped strip configuration.

10. The method of claim 8 further characterized by: stippling a design configuration in the surface of the body.

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11. The method set forth in claim 8 further

5 characterized by

* forming said body of a resilient rubber material.

12. The method set forth in claim 8 further characterized by: 10 forming said body of a rubber material which maintains over a long period of time the natural tacky feeling of leather regardless of weather conditions.