Patent Application
20170304687
The present disclosure relates to golf clubs and related sports applications. More particularly, it relates to enhanced surface strike performance of a golf club head, which may be achieved by a coating applied to the golf club head. Although a preferred embodiment of the present disclosure is directed to a golf club head, it is contemplated that other types of sports equipment (e.g., baseball bats, hockey sticks, polo mallets, croquet mallets bocce balls, bowling balls, billiard balls, etc., and the like) may similarly benefit from the enhanced surface strike performance disclosed herein.
The design of typical golf clubs includes specific features that affect the flight characteristics of the golf ball after impact. For example, the loft angle of the club, face grooves and surface characteristics of the club impart a combination of angular spin and forward velocity at impact. The forward velocity is further directed along a vector (launch angle) by virtue of the balls interaction with the clubface at impact.
The introduction of spin can be a benefit for the highly skilled golfer and allow the golfer to “work the ball” by deliberately curving the flight path in a left-to-right or right-to-left direction. High spin rates may also facilitate the skilled golfer in reducing the amount of travel on the ground-of short shots to the green (i.e., getting the ball to “check up”).
The vast majority of golfers are insufficiently skilled in the control of spin on the ball. Therefore, the inadvertent and errant introduction of spin commonly results in either hooking or slicing the balls flight path in an unintended direction.
At impact the club head transfers its kinetic energy to the ball. Conventional golf clubs impart some energy to spin the ball and the remaining energy to propel the ball. Depending upon the angle of impact of the club face the proportion of energy diverted to either spin or propulsion will vary.
It is preferable to configure a golf club head to achieve less spin, greater launch angle and increased carry distance. Historically, one known way modify these golf ball characteristics is to use a “slippery” clubface. For example, Vaseline®, Chopstick®, or other temporary substances applied to the striking face of the golf club is widely known. These practices, however, are not “legally conforming” to the Rules of Golf issued by the United States Golf Association (“USGA”), as these substances are “temporary modifications.” The removal of grooves on the golf clubface is also widely known in the industry to modify the aforementioned characteristics of golf balls, and clubs having groove-less and highly polished clubfaces are currently marketed today.
Several patents disclose a number of attempts to achieve these results. For example, U.S. Pat. No. 6,974,392 (“Chang”) describes a golf club for minimizing spin of the golf ball. The method described employs the use of low friction substances that cover the impact surface of the golf club, such as PTFE and variants of PTFE (Teflon). These substances are known for their low coefficient of friction, and are thus an obvious attribute for coating that is expected to reduce the spin of a struck golf ball.
Chang further describes how to overcome the limitations of the method that was previously discussed in U.S. Pat. No. 5,423,535 (“Shaw”). Shaw also listed PTFE as a candidate for spin reduction treatment of golf club face. While being somewhat effective, this approach of using PTFE had limited functionality and practicality. As a result, the PTFE coatings on the golf club did not reach the level of performance expectation. Chang describes the problem as ultimately relating to the softness of the PTFE and that at impact the compression of the golf ball into the layer of PTFE produces a mechanical engagement of the ball against the surface and introduces unexpected and unwanted spin of the golf ball. The solution proposed in Chang is to limit the thickness of the PTFE coating and employ a supporting layer under the PTFE. However, this limits the degree of mechanical engagement of the PTFE layer with the golf ball.
Thus, there is a need for a new and improved method and apparatus for providing a strike surface of a golf club which will overcome the above mentioned deficiencies while providing a better overall result. Specifically, the present disclosure overcomes the limitations of the existing attempts through the use of non-obvious methods.
The present disclosure relates to golf clubs and related sports applications. More particularly, it relates to an enhanced strike surface of a golf club head, which may be achieved by a coating applied to the golf club head.
In the present disclosure a much more significant portion of the kinetic energy is transferred to the propulsion of the golf ball forward/upward and a much lower amount of the energy (than conventional golf clubs) is converted to rotational energy that spins the ball. This results in an improved launch angle and greater carry distance than a conventional golf club for any given clubhead speed at impact and less inadvertent loss of accuracy from off axis spin of the ball.
In particular, the present disclosure describes a method for producing golf clubs that have design features and characteristics that enhance the directional accuracy, reduce the inadvertent hooking and slicing and improve the distance performance of a golf club of given loft angle.
The present disclosure overcomes the cost and complexity of such manufacturing techniques and results in a dramatic improvement in golf club performance.
Specifically, in accordance with one embodiment of the disclosure, a modification of the golf clubface is such that the ball striking surface does not have any grooves. In other words, the ball striking surface is substantially smooth. The ball striking surface has an advantageous combination of properties, such as smoothness, hardness and durability, adapted to improve golf club performance.
In another embodiment of the disclosure, the golf clubface includes a ball striking surface having surface features configured as one or more ridges or ribs. Alternatively, the one or more surface features can be configured as one or more grooves. In still a further embodiment, the one or more surface features can be configured as a combination of ridges and grooves. The ball striking surface with surface features has an advantageous combination of properties, such as smoothness, hardness and durability, adapted to improve golf club performance.
In a further embodiment of the disclosure, the ball striking surface of the clubface is provided by an insert attached to the clubface. The insert can be substantially smooth or can have surface features as described above. Moreover, the insert provides the ball striking surface having an advantageous combination of properties, such as smoothness, hardness and durability.
According to one aspect of the aforementioned present embodiments, the ball striking surface and the clubface can be integral such that the combination of advantageous properties, such as smoothness, hardness and durability, are intrinsic to the clubface and the ball striking surface. According to a second aspect of the above present embodiments, a coating chosen for its advantageous combination of properties, such as smoothness, hardness and durability, can be applied to the clubface. The clubface and the coating applied thereon define a ball striking surface having enhanced performance over similar golf clubs without the benefit of having the coating disclosed herein. The intrinsic coefficient of friction is not a critical characteristic of the chosen coating that results in the enhanced performance.
In one particular embodiment of the disclosure, a clubface is coated with an oil modified polyurethane to define a ball striking surface having enhanced performance. The resulting ball striking surface is superior to PTFE in durability, performance and cost of manufacture. Modified polyurethane coatings are typically used for the purpose of corrosion protection of metal surfaces. The application of these compounds to enhance the performance characteristics of golf clubs is both non-obvious and effective.
In another particular embodiment the golf clubface may be coated with a baked on porcelain material as used in non-stick cookware or appliance surfaces. Additionally, a ceramic coating may also be used to achieve the required surface properties. A powder coating of polyurethane or other acceptably hard and durable material may also be used.
Still other aspects of this disclosure will become apparent upon reading and understanding of the present disclosure.
For a better understanding of the present invention, reference may be had to the following detailed description taken in conjunction with the accompanying drawings in which:
A preferred embodiment of the present disclosure is a golf club of low cost manufacture that includes a ball striking surface able to perform to the above specifications. For a performance enhancing ball-striking surface to be practical and useful it must be durable, smooth, resist impact forces of normal use, and reduce the imparted spin on the golf ball. The USGA requires that the surface have a hardness that passes the ‘fingernail test.” This hardness corresponds to a Mohs hardness of 2.5, compared with a copper penny having a Mohs hardness of 3.0. The intent of this ruling is to render common lubricants, adhesive patches and other waxy or liquid substances that may be applied to the striking surface as non-conforming.
In contrast, existing methods use surface coatings (PTFE and its variants) with a specific coefficient of friction. Coefficient of friction is a complex property that is known to be unpredictable and can be highly dependent on normal forces at the contact surfaces as well as being limited by the mechanical properties of the substances being tested (i.e., hardness, compressive strength, yield strength, etc.). While PTFE would seem to be a viable substance to coat a golf club for reduced spin, it has been determined that, from a practical standpoint, PTFE has fails to be useful. In particular, PTFE is not sufficiently durable or impact resistant to satisfy the requirements of a viable surface of a golf club.
According to one embodiment of the present disclosure, a ball striking surface of the clubface is substantially smooth. In another embodiment, the ball striking surface has of the clubface has one or more surface features. In another embodiment, the ball striking surface may be the surface of insert attached to the clubface of the golf club. The insert may be substantially smooth or may include one or more surface features. According to one aspect of the present embodiments, the ball striking surface and the clubface of the golf club head are integral. In other aspects, the ball striking surface may be supplied by a coating applied on a clubface of the golf club head. The ball striking surface of the golf club satisfying the physical attributes listed below, while still meeting the physical attributes required by the USGA, will reduce a spin rate, increase a launch angle, and increase a carry distance on the golf ball compared with a similar golf club without the ball striking surface of the present disclosure.
Specifically, in accordance with the preferred embodiment of this disclosure, the resulting ball striking surface 18 (see
a) A hardness of greater than Shore D 65;
b) A surface roughness Ra of 1.0 micron or less (i.e., a substantially smooth surface), where Ra is the roughness average of the ball striking surface's measured microscopic peaks and valleys;
c) A wear resistance minimum of zero loss at 1 kg per 1000 Cycles (ASTM-C-501);
d) A flexural strength of greater than 3000 psi (ASTM C-580);
e) An indentation resistance (Mil-D-3134F sec 4.7.4) of greater than 1500 psi for a duration of 30 minutes;
f) A tensile strength of greater than 3000 psi (ASTM C-307); and
g) A compressive strength of greater than 5000 psi.
A ball striking surface having a combination of some or all of properties a)-g) above has been found to dramatically improve the performance characteristics of a golf ball struck by the ball striking surface. For example, the hardness and compressive strength properties of the ball striking surface in combination with the smoothness prevents the golf ball from developing significant mechanical engagement with ball striking surface upon impact with the golf club, thereby reducing the amount of imparted spin.
Referring now to
Referring back to
The embodiment illustrated in
In other embodiments, the separate insert 32 is configured as an overlay insert (not shown). When the insert 32 is configured as an overlay, the insert is attached to the clubface 16 to provide the ball striking surface 18 comprising substantially all of the clubface of the golf club head 30. In other words, when configured as an overlay, the entire clubface 16 acts as the receiving portion for the insert 32 such that the insert completely overlays or covers the clubface. Again, when configured as an overlay insert, the insert 32 is attached to the clubface in the same manner as discussed above, i.e., through the use of adhesives or mechanical fasteners known in the art.
The ball striking surface 18 of the separate insert 32 attached to the clubface 16 of golf club head 30 can be configured similarly to that of golf ball heads 22, 26 illustrated in
In some embodiments, the insert 32 is removably attached to the clubface 16. Such a configuration allows the insert 32 to be removed from the clubface 16 whenever desired by the user of the golf club. After a significant period of use, the ball striking surface 18 may exhibit a degradation in performance characteristics due to, for example, the forceful nature of the impact between golf clubs and golf balls, the presence of debris (e.g., sand, dirt, grass, etc.), and/or exposure to natural elements (e.g., sunlight, water, cold air, etc.). As such, a user may want to remove the insert 32 for reconditioning or replacement of the ball striking surface 18, thereby saving on costs which might otherwise be spent on replacing the entire golf club. Moreover, manufacturers over time may release upgraded or improved inserts and ball striking surfaces for various golf club models. A removable insert permits a golf club user to upgrade just the striking surface of the golf club head, as opposed to the entire golf club.
In accordance with a preferred embodiment of the disclosure, the ball striking surface 18 of each of the golf club heads described above and shown in
In particular, the properties of hardness, indentation resistance or compressive strength, and smoothness are preferred. A ball striking surface with some or all of the properties a) through g) described above also imparts improved durability, such that the ball striking surface can withstand repeated forceful golf ball impacts without a significant degradation in performance (a common problem with PTFE coatings). The ball striking surface 18 thus forms a support structure for carrying the force of a golf ball impact from the clubface 16 to the heads 14, 22, 26, and 30 with minimal, if any, indentation.
In accordance with one aspect of the embodiments of the present disclosure, the ball striking surface 18 and the clubface 16 of the golf club heads 14, 22, 26, and 30 are integral. That is, the ball striking surface 18 and clubface 16 are included as part of a whole rather than supplied separately. In such an embodiment, the advantageous combination of properties disclosed herein is intrinsic to the clubface and the ball striking surface. This may be achieved, for example, by manufacturing the golf club head, clubface, and ball striking surface from the same material having the advantageous combination of properties. As another example, a surface treatment could be performed on the clubface to form the ball striking surface with the combination of properties, such as through a surface hardening or work hardening process known in the art.
The coating 20 forming the ball contacting surface 18 is adapted to impact an associated golf ball and transfer the kinetic energy of the golf club to the golf ball. In this regard, the ball striking surface 18 comprising the coating 20 may comprise substantially all of the clubface 16 of the golf club head 14, or just a portion thereof. For example, the coating 20 can be applied at a centrally located “sweet spot” of the clubface, or could be applied to cover the entire clubface. Moreover, while golf club head 14 is illustrated in
If the coating 20 is applied to head 22 of
Referring now to golf club head 30 of
With reference back to
A process for applying the polyurethane coating 20 to the clubface 16 or insert 32 of a golf club will now be described. If a substantially smooth ball striking surface is desired, an optional first step is to smooth out the clubface or insert by removing any unwanted surface features and roughness on the clubface by techniques know in the art, including grinding, sanding, etc., and the like. If the clubface or insert is to include surface features, or is already prepared to an adequate smoothness, a surface preparation step is first performed. The surface preparation step involves removing all visible oil, grease, soil, dirt, and other contaminants from the golf club head. Surface preparation can also include an acid etching step known in the art to clean the clubface or insert. The coating can then be disposed on the clubface or insert using known application techniques, such as spraying, airless spraying, brushing, or rolling. Additional layers of coating are then applied as desired, allowing each preceding coat to dry for approximately 1 to 2 hours before application of subsequent coat layers. In some particular embodiments, 3 to 4 layers of coating has been found to impart the advantageous combination of properties to the ball striking surface of the golf club heads disclosed herein. Once the desired number of coating layers is applied, the coating should be allowed to cure for approximately one day.
A coating comprising modified polyurethane provides a ball striking surface 18 superior to PTFE in durability, performance and cost of manufacture. Modified polyurethane coatings are typically used for the purpose of corrosion protection of metal surfaces. The application of these compounds to enhance the performance characteristics of golf clubs is both non-obvious and effective.
It is contemplated that other coatings and materials can be used and applied to the clubface to provide a ball striking surface having the advantageous combination of properties disclosed herein. For example, the golf clubface may be coated with a baked on porcelain material as used in non-stick cookware or appliance surfaces. Additionally, a ceramic coating may also be used to achieve the required surface properties. A powder coating of polyurethane or other acceptably hard and durable material may also be used.
Moreover, even though
The following example is provided to illustrate the processes of the present disclosure. The example is merely illustrative and is not intended to limit the disclosure to the materials, conditions, or process parameters set forth therein.
Tests were performed to show the advantage of utilizing a ball striking surface having the advantageous combination of properties disclosed herein, including hardness, smoothness, and durability. Various performance characteristics associated with the game of golf can be improved through the use of the ball striking surface having this advantageous combination of properties. Such performance characteristics include an increased launch angle of the golf ball, a decreased spin rate of the golf ball, and an increased carry distance (e.g., yardage) of the golf ball.
Two golf clubs of the same type and brand were acquired. In particular, two Callaway® 9-irons were used, each having a 39° loft. One of the golf clubs was modified to have the ball striking surface disclosed herein for comparison with the other golf club, which was left unmodified. To provide the modified golf club with the ball striking surface, a coating of polyurethane material commercially available under the trade name POR-15®, and having the advantageous combination of properties disclosed herein, was used. POR-150 was coated on the clubface of the modified golf club in accordance with the method discussed above.
Numerous golf balls of the same brand were struck with the modified and unmodified golf clubs and various measurements were recorded. Using a FlightScope® ball tracking monitor, radar, and launch monitor, the golf ball carry distance, golf ball speed, club speed, golf ball spin rate, and golf ball launch angle were recorded for each golf shot with the modified and unmodified golf club. The shots were taken outside to simulate real-world conditions, and the data was collected for the full flight of the ball. In other words, the carry distances of the golf balls was actually measured and not extrapolated from initial launch conditions. The results are presented in Table 1 below:
As shown in Table 1 above, the modified club produced between about 16 yards to about 45 yards increased carry distance and an average increased carry distance of over 30 yards compared with the unmodified golf club, with no significant increase in ball velocity. In addition, the launch angle achieved by the modified golf club increased by as much as about 7 degrees, with an average launch angle increase of about 2 degrees compared with the unmodified golf club. Moreover, the modified golf club decreased spin rate by as much as about 70%, with an average decrease in spin rate of about 60% compared with the unmodified golf club. In summary, the results in Table 1 show that a ball striking surface having a combination of properties a)-g) disclosed above will increase the launch angle of the struck ball and reduce the spin rate. As a result, longer and higher ball flight, less lateral dispersion of an incorrectly struck ball, and a more beneficial descent angle are achieved.
The improved performance characteristics achieved by the modified golf club is attributed to the ball striking surface having the advantageous combination of properties disclosed herein. For example, properties such as hardness and resistance to indentation of the ball striking surface, in combination with the smoothness, prevents the golf ball from developing significant mechanical engagement with ball striking surface upon impact with the golf club, thereby reducing the amount of imparted spin. Because less kinetic energy is converted to rotational energy that spins that ball, a much more significant portion of the kinetic energy is transferred to the forward/upward propulsion of the golf ball, thereby improving the launch angle and increasing the carry distance. The application of ball striking surfaces having this combination of properties to enhance the performance characteristics of golf clubs is un-expected, effective, and non-obvious.
The exemplary embodiment has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiment be construed as including all such modifications and alterations insofar as they come within the scope of the above disclosures or the equivalents thereof.
This application claims priority to U.S. Provisional Patent Application Ser. No. 62/325,124, filed Apr. 20, 2016, the entirety of which is fully incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62325124 | Apr 2016 | US |
