US2991080A - Golf club shaft - Google Patents

Description

July 4 1961 E. J. REDMOND GOLF CLUB SHAFT `Fled Jan. 28, 1958 INVENTOR. EDM/ARD J. foMo/VD 2,991,080 GOLF CLUB SHAFT Edward J. Redmond, Escondido, Calif., asslgnor to Woolley Manufacturing lCompany, Escondido, Calif.,`

a corporation of Illinois Filed Jan. Z8, 1958, Ser. No. 711,600

5 Claims. (Cl. 273-80) This invention relates generally to an implement shaft and, more particularly, is concerned with a golf club shaft formed of a tubular metallic core associated with an outer casing of resinimpregnated glass bers.

In the past golf club shafts have been made primarily from two materials, namely, hickory and steel, `and a small number of shafts have been made from split bamboo. The wooden golf club shafts had numerous faults in that any of them, including hickory and split bamboo, were susceptible to variations in physical characteristics in response to climatic changes. Solid steel shafts also had faults, particularly in that they were heavy and bulky and had a tendency to twist at the moment of impact with the golf ball.

'Ihe introduction of the tubular steel shaft eliminated some of these diiculties in that it permitted the playerlto deliver more power to the club head and it was not responsive to variations in climatic conditions, as were shafts made from wood. However, with the tubular steel Y shaft an extremely important operational response was lost, namely, a somewhat intangible, but nevertheless real and important, rm and smooth feel delivered to the players hands at the moment of impact of the club head with the ball.

This defect has been remedied to a considerable extent by the recent introduction of lgolf club shafts made in whole or in part from resin-impregnated glass ber, and particularly by a golf club shaft comprising a tubular steel core with a resin-impregnated, glass ber fabric wrapped around the outside of the core and extending from one end to the other thereof. Such a structure is disclosed in my copending application Serial No. 466,772, entitled Golf Club Shaft, and assigned to the assignee of this application, now Patent No. 2,822,175.

-Whilethis club is highly successful and has satisfactorily met most of the objectives set out for it, it is not arranged in a way to obtain the necessary shading in weight, balance and other characteristics required for the provision of a complete line of matched golf clubs. Presently, the weight of a golf club having ay glass Wrapped, metal Icore shaft isaltered by changing'the weight in the head or the weight of the tubular insert, or by changing the amount of glass fabric wrapped around the insert. However, when a weight adjustment is effected by any of these methods, it necessarily also results in a change in other aspects of the club, such as the stiffness of the club shaft and the feel of the club, which will often produceundesirable results in addition to the desired change inI weight.

This problem of weight and balance adjustment is also presentin existing golf clubs having tubular steel shafts. Usually, the balancing of such clubs is restrictedl to changes in the weight of the club head. For example,V

Wooden headed golf clubs are often provided with lead Y inserts to compensate for smaller head sizes in the short range clubs.

However, I have now discovered that the weight and balance of said glass wrapped clubs may be adjusted to an appreciable degree, without disguring the club head, without appreciably changing manufacturing procedures, and without disturbing the shaft structure or its functional characteristics between the club head and hand grip, by

controlling the extent towhich the glass ber sheathing i ice of either or both of the hosel and the grip. Where, asin the usual case, the hosel and/ or grip are counterbored to receive the sheathing, the weight usually varies in proportion to the amount of overlap between the sheathing and either or both of the hosel and grip. Y

Accordingly, a major object of the invention has been to provide a golf club shaft having the desirable features of a tubular steel shaft insofar as durability and strength Y are concerned and also the desirable feel characteristic of a split bamboo or hickory shaft.

A further object of the invention has been to provide a golf club shaft which will have substantially the same appearance as that of presently known shafts.

A further object of the invention has been to provide a golf club shaft wherein the weight and balance ofthe club may be readily adjusted in the manufacturing operation without introducing undesirable features or alterations in the shaft construction, thus making it possible for the manufacturer to provide a set of accurately matched golf clubs all having the same feel `A further object of the invention has been to provide a structure for a golf club shaft wherein said weight and balance adjustments can be made without materially departing from the general organization and construction of previously known steel core golf club shafts having a resin-impregnated, glass fabric casing.

A further object of the invention has been to provide a golf club shaft which smoothly dampens shock occasioned by the impact of the golf club head with a golf ball, whereby a minimum of energy is dissipated in shaft vibration, thereby enabling the club to effect longer and more accurate drives and with less fatigue for the player.

A further object of the invention has been to provide a Igolf club shaft which will minimize the twisting of the club head at the moment of impact with the ball and thereby result in a straighter and more predictable flight for the golf ball.

Other objects and purposes of this invention will become apparent to persons acquainted with structures of the type disclosed herein upon reading the following specication and examining the accompanying drawings, in which:

FIGURE 1 is a broken, side elevational view of a golf club embodying the construction of the invention, portions thereof being shown in central cross-section.

FIGURE 2 is a sectional view taken along the line II-II of FIGURE 1.

FIGURE 3 is a sectional view taken along the line III-III of FIGURE 1.

FIGURE 4 is a side elevational View of a tubular shaft core about to be wrapped with a sheet of resin-impregnated, glass fabric to form a tapered golf club shaft.

FIGURE 5 is a fragment of FIGURE 1 showing an alternate construction for the lower end of the golf club.

FIGURE 6 is a fragment of FIGURE l showing an alternate construction for the upper end of the golf club.

For the purpose of convenience in description, the tenus nipperf lower and vderivatives thereof will have refer- A ence to the golf club shaft construction in its normal posi- General description In general, the inventionincludesy a constructionpfor a Patented July 4, 1961V golfclub havingla shaft comprising, a hollow metal core which is encased in, and bonded to a woven, glass ber fabric which extends from a point near one end of the core-to a point near the other end.' ofthe core: The glass ber fabric is impregnatedwithza resin, such as a thermosettingplastic, which holds lthe glassJ bers of the fabric securely with respect to each other as well aswith respect to the hollow metal core which they encaseand to which the resin adheres; A hand grip` and a substantially conventional golf club head areV mounted upon, and secured to,` the opposite ends of the sha-ft sothat they are in engagement with the encasing material, including the glass fabric and thermosetting plastic.

Through properchoice of the hollow metal core and the corresponding amount of glass ber fabric in which said core is encased, the resulting golf club shaft may have substantially the same size and shape as a conventional completely metal golf club shaft. Thus, conventional equipment and procedures for manufacturing golf clubs can be utilized, or at least closely approximated, in oompleting the fabrication of a golf clubproduced with the shaft construction to which this invention relates.

Ithas been found, for reasons not fully understood, that a hollow metal core encased Within, and bonded to, a resin-impregnated glass ber fabric is capable of dampening, and/or reducing the transmission of shocks, vibrations and torsion, produced by impact with a golf ball, in amanner previously not achieved. It is believed, but not experimentally veried with certainty, that the dissimilar-ity in the characteristics of the metal core and the encasing material may result in` dissimilar and/or interfering periods of vibration which tend to dampen each other. It is further believed that the glass bers, having a high tensile strength, act to reduce torsion, as Well as distortion in the club shaft. It has also been found that these results are precuilar to, and achieved only by, this particular combination of materials. Thus, vibrations which would normally be transmitted through a golf club shaft, and shock which would effect various undesirable distortions in `existing steel shafts, with consequent loss of energy and erratic shots, are quicklyv and'smoothly dampened where the golf club shaft of the invention is used. Thus, a golf clu'b including the shaft of the invention has been found capable of producing longer and more accurate shots while insulating the hands of the player from shocks and vibrations produced by lthe impact of the golf club head 'with a golf ball and at the same time reducing thev torsion and distortion in the golf club shaft normallyy produced by such impact.

The reference character (FIGURE 1) designates generally one form of golf club constructed in accordance with the invention, it being immaterial to the shaft construction of the invention whether the club is a wood or an iron.

Detailed construction:

The club 10 (FIGURE 1) has an elongated shaft 11, a grip 12 and head 13. In accordance with the invention, the shaft 11 is formed ofa hollow core 16 of tempered steel tubing. In substantially all materialrespects, the core 16'may be made exactly like the steel shaft of the conventional club, except that its outer diameter is somewhat less to compensate for the glass sheath which shortly will be described. The length of the shaft 11 is the same as in the case of the usual golf club shaft.

The core 16 is encased in a sheath 18 of resin-impregnated glass ber fabric, which is bonded by said resin to said core so that it is substantially integral therewith and extends from a point near one end of the core to a point near the other end of the core. At the upper end of the club 10, aV plug 20 is inserted into the open end of the core 16 and an ornamental end button 21 covers the plug 20. The grip 12 is formed about the club in any suitable manner and may be of'thel usual rubber, cork, leather, or the like. An ornamental collar 23 smooths` out the junction-between grip andthe'exposed portion of the shaft 11.

It will be observed that, in this particular embodiment, the glass fabric casing 18 terminates 'at its upper end adjacent to the lower end of the grip 12 so` that the grip is mounted directly upon the steel core 16. Thus, the grip 12 may be formed around the upper end of the shaft 11 as though the shaft were of conventional construction and, therefore, no special'machinery or equipment is needed in such assembly.

A-t the lower end ofthe shaft 11, the core 16 is inserted into the usual recess 25 formed in the shank or hosel 26 of the head 13, where said core 16 is securely held by means such as the pin 27 in a substantially conventional manner. The glass fabric casing 18 terminates, in this particular embodiment, at its lower end adjacent to the upper end of the hosel 26. Thus, the club head may be mounted upon the steel core 16 in a substantially conventional manner. An ornamental sleeve 29 smooths out the joint between the shaft and the hosel.

A golf club fabricated with the shaft construction described above has substantially the same weight and balance, or feel, as an existing ordinary golf club, not equipped with the shaft of the invention, except from the time when the impact occurs between the golf ball and golf club head, until the time when normal distortions and vibrations set up by such impact in conventional golf club shafts would be substantially dissipated. By virtue of the shaft construction of the invention, superior results are achieved and, by actual tests, longer and more accurate shots can be obtained by golf clubs embodying the invention.

In a preferred embodiment of the invention, as set forth above, lthe glass ber fabric30 (FIGURE 4) was comprised of woven glass bers, about half of which intersect the other half at suitable angles, which normally in present practice will 'be substantially at right angles. This glass fabric, which was approximately .007 inch in thickness, 'was impregnated with a polyester resin. It will be recognized that glass bers may be woven in other arrangements so long as the resultant fabric is capable of positively resistingV stretching in selected directions both prior to and after impregnation with the resin. Iny general, this requirement necessitates that the warp and woof bers be arranged substantially perpendicularly. Further, other types of resins having similar shock resisting and bonding characteristics, such as phenolformaldehyde rcsinand certain epoxy resins, may be used in place of the polyester resin. From three to ve layers of such glass ber fabric have been found to provide a satisfactory casing 18.

FIGURE 4 shows one preferred method of forming the glass fabric sheath around a metal tube having a substantially constant diameter and wherein, therefore, the taper, if desired, is provided by varying the amount of fabric crosswise of the core. A sheet 30 of resin-impregnated glass fabric is cut in a somewhat half-trapezoidal form wherein the end edges 31 and 32 are substantially perpendicular to one lengthwise edge 33. The other lengthwise edge 35 of the sheet 30 is at a slight angle with the edge 33 to effect a taper. The steel core 16 isplaced along, and against, the sheet 30 adjacent to the edge 33, and the fabric 30 is rolled upon said core. In this manner, a -wide variety of shapes may be readily secured in the completed shaft both by modifying the shape of the steel core and by varying the width and shape of the glass ber sheet. Thus, a core having a uniform diameter, which is relatively inexpensive to produce by comparison with a tapered core, can be converted into a tapered shaft of desired taper by controlling the angle between the edges 33 and 35 of the sheet 30.

With the fabric 30.wrapped onto the steel core y16, the resin is then rigidied in any conventional manner. The shaft may then be further nished, if necessary, by grindingvoif'- the roughedges ofthe resin-impregnated fabric toprovidel a smooth surface having the desired amount, if any, of taper. The shaft may be further finished, if

desired, by coating it with any convenient finishing material, such as a clear or colored lacquer.

The core 16 :is advantageously of constant diameter, because of cost considerations. However, a tapered core similar in shape to conventional tapered steel shafts may, if desired, be used. In one instance, for example, a tapered core of proper temper and resilience was provided with an outside diameter which varied smoothly from .542 inch at the upper end to .300 inch at the lower end. 'Ilhe glass fiber sheath, which varied in thickness approximately between .022 and .029, was formed by wrapping a strip of resin-impregnated glass fiber, preferably cut on a bias, about the metal core with the edges abutting to `give a smooth outer surface. The glass fabric Was pre-impregnated with `a resin in any conventional manner, said resin being of any desired type, preferably of thermosetting nature. The curing `of the resin may be accomplished in any conventional manner, either in air or in ovens and it may under some circumstances be done in a mold lalthough this latter has been found neither necessary nor particularly convenient. The heating of the resin, where as is usual the resin is thermcsetting, immediately prior to its setting causes the resin to ow and become an integral part of the coating. When this occurs, the joints between abutting .portions of the strip are impossible to nd, so that the entire sheath takes on an appearance of an integral coating. In fact, the physical eifect of curing is to produce this sheath as a single tube of thermosetting plastic Iwith the bers bonded to each other and to the core.

The materials and some of the techniques involved in applying this glass casing are described in considerable detail in the prior art, and especially of interest are United States Letters Patent 2,590,493, issued to Berberich et al. on March 25, 1952, and 2,614,058, issued to Francis on October 14, 1952.

Referring to FIGURE 5, it will be seen that the resinimpregnated glass fabric casing 40 will in some instances extend partially into the hosel 41 of the golf club head 42. In such case, the recess 43 in the hosel 41 is provided with a counterbore 44 to receive the yadjacent end of the glass fabric casing 40. The distance which the casing 40 extends into the hosel 41 may be varied rather substantially and thereby used ias a means of varying and accurately adjusting the weight and balance of the golf club.

More specifically, and in one particular embodiment, cach hosel 41 in a set of ygolf club heads is constructed with suicient body that it can be counterbored substantially the full length of the recess 43, in order to receive a corresponding extension of the casing 40, without materially weakening the hosel or the remainder of the golf club head. 'Ihe specific :gravities of the principal materials, namely wood or heavy metal, used in golf club heads are materially different than the specific gravity of the material, namely a resin-impregnated, glass fiber fabric, selected for the casing 40. Thus, where the club head is fabricated from -a meta-l, such as iron or brass, which are considerably heavier by volume than the resin-impregnated glass fabric comprising the casing 40, the net weight of the club head is reduced by increasing the axial length of the counterbore 44 in the hosel 41. Where the golf club head is made of wood, which is substantially lighter by volume than the resin-impregnated glass fabric in the casing 40, the weight of the club bead is reduced by decreasing the axial length of the counter-bore 44 in the hosel 41. However, in both cases, the clubs are accurately matched and balanced by varying the extension of the casing 40 into the hosel 41, hencey by varying the amount of material removed by the counterbore 44 which receives said casing.

It will be recognized that this control procedure is intended primarily to effect nal, delicate adjustments in the weight and balance of the club. Ordinarily, the principal balancing and matching will be accomplished in the usual manner.

V6 l:FIGURE 6 illustrates a structure for the upper end of the golf club shown in FIGURE 1, wherein the principles discussed `with respect to the structure shownin FIGURE 5 are adapted to the upper end of the golf club. That is, the resin-impregnated iglass ber casing 40 extends upwardly into the grip portion 46 a variable land preselected amount, as desired or required, i-n order to effect weight and balance control and, in some instances, to provide greater shock reduction.

Although particular preferred embodiments of the invention have been disclosed in detail hereinabove for illustrative purposes, it will be understood that vari-ations and modifications of such disclosure, lwhich lie within the scope of the appended claims, are fully contemplated.

What is claimed is:

1. A golf club, comprising: an elongated, stiff and tubular metal core capable of substantial non-fatiguing exion and torsion; at least one layer of woven, glass fabric encasing said core from a point near one end thereof to a point near the other end thereof, approximately half of the fibers in said fabric being substantially perpendicular to the remainder of said fibers and to the lengthwise extent of said core; a rigidied resin impregnated into said glass fabric and securely bonded to said core and to the fibers of said fabric and bonding said fabric to said core to form a shaft, said core extending beyond at least one of the ends of said fabric a preselected distance so that the weight and balance of said shaft may be controlled by preselection of the location of the ends of said fabric with respect to the ends of said core, said resin and said fabric cooperating with said core to dampen materially the flexion and torsion imposed upon said shaft by normal use thereof, said resin being capable of maintaining said bond when extreme shocks and vibrations are imparted to said shaft; a golf club head having a hosel, one end of said core being received into, and rigidly secured to, said hosel and said hosel being in engagement with one end of said resin-impregnated glass fabric; and a grip surrounding, and positively secured to, the other end of said core, said grip being in engagement with the other end of said resin impregnated fabric.

2. The structure of claim 1 wherein said tubular metal core has a substantially constant external diameter throughout its length, said hosel has a cylindrical recess into which said one end of said core is snugly and slidably receivable, and said hosel has a counterbore coaxial with said cylindrical recess, the resin-impregnated glass fabric encasing said core extending into said counterbore a preselected distance, whereby the weight and balance of the lower end of said golf club are precisely controlled.

3. The structure of claim 1 wherein said hosel and said hand grip are telescoped over the corresponding adjacent ends of the resin impregnated glass fabric encasing said core, the amount of such telescoping being preselected to effect a precise control over the weight and balance of the corresponding end of said golf club.

4. The structure of claim 1 wherein the hosel has a counterbore of preselected length and said resin-impregnated, glass fabric is received into said counterbore, said resin-impregnated fabric having a specific gravity materially different than the specific gravity of the material in said hosel.

5. A golf club comprising a stiff, resiliently ilexible and twistable tubular steel core capable of substantial nonfatiguing liexion and torsion; a sheet of woven, glass fabric having a iirst lengthwise edge extending from a point near to, but spaced from, one end of said core to a point near to, but spaced from, the other end of said core, second and third edges extending from, and transversely to, said first edge and a fourth edge extending between said second and third edges and being at all points therealong at a distance from said first edge at least equal to the circumference of the adjacent portion of said core, the ends of said rst edge being spaced preselected disbeing arranged with substantially half of its fibers dis' posed substantially at right angles to the other half of said bers; said fabric being impregnated with a rigidied thermosetting resin bonded to said core and said fabric to define a one-piece shaft, said resin being capable of withstanding the flexion and torsion developed by the use of Said golf club; a golf club head having a socket into which said core -is snugly and slidably receivable, said head being in engagement with the resin-impregnated glass fabric and rigidly secured to said core; a grip surrounding, and positively secured to, the other end of said core, said gnp Y y 8 Y being engaged'with the adjacent portion of said` resin-impregnated glass fabric; whereby shocks and vibrations imparted to said head by impact. with a golf ball will bematerially dampened before they reach said grip andthe vexibility and twistability of said core will be materially reduced and the weight and balance of said shaft may be precisely controlledrby preselection of the length of said rst edge.

References Citedl in the le of this patent UNITED STATES PATENTS Grimes Oct. 8, 1957 Redmond Feb. 4, 1958

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