Patent Application
20130017904
Golf clubs, especially wood type golf clubs such as driver, fairway woods, and hybrids can provide large “sweet spots” to reduce the ill effects of mishits. In addition, golf club makers provide such clubs with mass distributions that can tend to promote particular ball trajectories, and have preferred club head moments of inertia. Mass distribution in some such clubs can be readily adjusted by a golfer to promote a selected shot properties such as a fade or draw to compensate for individual swing characteristics.
Driver type golf clubs with large heads can provide golfers with enhanced confidence when they approach a shot. However, club manufactures have not recognized and addressed how club head sounds relate to golfer playing experience. Some large driver type club heads produce loud and unpleasant sounds when used to strike a ball. Some golf equipment reviewers have suggested that in some cases, a particular driver should come with earplugs. Thus, golf clubs, especially driver type golf clubs are needed that can provide superior sound characteristics.
Methods comprise selecting a striking face material for a golf club head, and selecting a striking face area and thickness. A striking face acoustic mode frequency is determined, and based on the determined frequency, the striking face is adjusted. In some examples, the striking face is adjusted by varying a thickness or selecting a material having a different elastic constant or density. Typically, the club face is adjusted so that a lowest resonance frequency of the club face is greater than about 3.8 kHz, 4.0 kHz, 4.2 kHz, or 4.5 kHz. In other examples a sole acoustic mode or a crown acoustic mode at a frequency less than about 3.5 kHz is identified, and the sole or crown is adjusted so as to reduce an amplitude of the sole or crown acoustic mode when striking a golf ball. In some embodiments, a sole acoustic mode or a crown acoustic mode at a frequency less than about 2.5 kHz or 2.0 kHz is identified. In other examples, an A-weighted sound pressure or a sound level in response to a ball strike is determined. If the sound pressure or sound level exceeds a limit associated with a satisfactory sound, the club head is adjusted. In some examples, the limit is 225 sones or an A-weighted sound pressure of 5 Pa in response to a golf ball strike at a club head speed of about 110 mph. (As used herein, A-weighted sound pressures are at a distance of about 1 m). The “golf ball” used in all tests described herein is a TaylorMade® Tour Preferred® TP Red golf ball.
Driver type golf club heads include a club body configured to receive a striking plate and a composite striking plate configured to have a lowest order acoustic resonance frequency at a frequency of at least 3.8 kHz. In some examples, the composite striking plate is configured to have a lowest order acoustic resonance frequency at a frequency of at least 4.0 kHz or 4.2 kHz. In some examples, an A-weighted sound level is less than about 5 Pa in response to a 110 mph ball strike at the striking plate. In other examples, a sound level is less than about 225 sones in response to a 110 mph ball strike. In some examples, a striking plate toe to head distance is at least about 60 mm at a striking face center and a striking plate crown to sole distance is at least about 60 mm at a striking face center. In other embodiments, an associated CT is less than about 257 μs or a COR is less than about 0.83.
Methods comprise determining an acoustic resonance frequency of a driver type golf club head sole, crown, or face, and evaluating the resonance frequency to determine if a club head is to be adjusted. Based on the evaluation, at least one of the following adjustments is performed: selecting a less dense material for a crown, sole, or face; altering a face thickness, thinning or thickening a club face at an antinode of the acoustic resonance. In some examples, an acoustic level associated with a club face/golf ball impact is determined, and the club head is adjusted based on the determination.
With reference to the illustrative drawings, and particularly
With reference to
Due to the efficiency of prepreg plies of low FAW, the face insert 14 can be relatively thin, preferably less than about 4.5 mm and more preferably less than about 3.5 mm. Thus, use of the face insert 14 results in weight savings of about 10 g to 15 g over a comparable volume of metal used in the body 12 (e.g., Ti-6Al-4V). As mentioned above, this weight can be allocated to other areas of the club, as desired. Moreover, the club head 10 has demonstrated both superior durability and performance. In a durability test, the club head 10 survived over 3000 impacts of a golf ball shot at a velocity of about 44 m/sec. In a performance test of the club's COR, measured in accordance with the United States Golf Association Rule 4-1a, the club head had a COR of about 0.828.
With continued reference to
A suitable carbon fiber reinforcement comprises a carbon fiber known as “34-700” fiber, available from Grafil, Inc., of Sacramento, Calif., which has a tensile modulus of 234 Gpa (34 Msi) and tensile strength of 4500 Mpa (650 Ksi). Another suitable fiber, also available from Grafil, Inc., is a carbon fiber known as “TR50S” fiber which has a tensile modulus of 240 Gpa (35 Msi) and tensile strength of 4900 Mpa (710 Ksi). Suitable epoxy resins known as Newport 301 and 350 are available from Newport Adhesives & Composites, Inc., of Irvine, Calif.
In a preferred embodiment, the composite region 16 includes prepreg sheets having a quasi-isotropic fiber reinforcement of 34-700 fiber having an areal weight of about 70 g/m2 and impregnated with an epoxy resin (e.g., Newport 301) resulting in a resin content (R/C) of about 40%. For convenience of reference, the primary composition of a prepreg sheet can be specified in abbreviated form by identifying its fiber areal weight, type of fiber, e.g., 70 FAW 34-700. The abbreviated form can further identify the resin system and resin content, e.g., 70 FAW 34-700/301, R/C 40%. In a durability test, several plies of this material were configured in a composite region 16 having a thickness of about 3.7 mm. The resulting composite region 16 survived over 3000 impacts of a golf ball shot at a velocity of about 44 m/sec. In another preferred embodiment, the composite region 16 comprises prepreg plies of 50 FAW TR50S/350. This material was tested in a composite region 16 having a thickness of about 3.7 mm and it too survived a similar durability test.
With reference to
With continued reference to
Preferably, the thickness of the composite region 16 is about 4.5 mm or less and the thickness of the metallic cap 18 is about 0.5 mm or less. More preferably the thickness of the composite region 16 is about 3.5 mm or less and the thickness of the metallic cap 18 is about 0.3 mm or less. The metallic cap preferably comprises a titanium alloy.
The metallic cap 18 defines a striking face 40 having a plurality of grooves 42. The metallic cap 18 further aids in resisting wear from repeated impacts with golf balls even when covered with sand. Preferably, a bond gap 44 of about 0.05 mm to 0.2 mm, and more preferably about 0.1 mm, is provided for adhesive attachment of the metallic cap 18 to the composite region 16. In an alternative embodiment, the bond gap 44 may be no greater than 0.2 mm. The metallic cap 18 is preferably formed of Ti-6Al-4V titanium alloy; however, other titanium alloys or other materials having suitable characteristics can be employed. For example, a non-metallic cap, such as a cap comprising injection-molded plastic, having a density less than 5 g/cc and a hardness value of 80 Shore D may be employed.
As mentioned above, it is beneficial to have a composite region 16 that is relatively free of resin rich regions. To that end, fiber reinforcement sheets are impregnated with a controlled amount of resin to achieve a prescribed resin content. This is realized, in part, through management of the timing and environment in which the fiber sheets are cured and soaked.
The plies can be cut at least twice before achieving the desired dimensions. A preferred approach includes cutting plies to a first size, debulking the plies in two compression steps of about two minutes each. Thereafter, the plies are die cut to the desired shape, and compressed a third time; this time using a panel conformed to the desired bulge and roll. The plies are then stacked to a final thickness and compressed a fourth time with the conformed panel for about three minutes. The weight and thickness are measured preferably prior to the curing step.
The plies can be cut at least twice before achieving the desired dimensions. A preferred approach includes cutting plies to a first size and debulking the plies in two compression steps of about two minutes each. Thereafter, the plies are die cut to the desired shape, and compressed a third time using a panel conformed to the desired bulge and roll. The plies are then stacked to a final thickness and compressed a fourth time with the conformed panel for about three minutes. The weight and thickness of the plies are measured preferably prior to the curing step.
An alternative soaking and curing profile is depicted in
In order to increase the surface roughness of the composite golf club face and to enhance bonding of adhesives used therewith, a layer of textured film can be placed on the material before curing. An example of the textured film is ordinary nylon fabric. Curing conditions do not degrade the fabric and an imprint of the fabric texture is transferred to the composite surface. Tests have shown that adhesion of urethane and epoxy, such as 3M® DP460, to the treated composite surface was greatly improved and superior to adhesion to a metallic surface, such as cast titanium alloy.
In order to increase the surface roughness of the composite region 16 and to enhance bonding of adhesives used therewith, a layer of textured film can be placed on the composite material before curing. An example of the textured film is ordinary nylon fabric. Curing conditions do not degrade the fabric and an imprint of the fabric texture is transferred to the composite surface. Tests have shown that adhesion of urethane and epoxy, such as 3M® DP460, to a composite surface treated in such a fashion was greatly improved and superior to adhesion to a metallic surface, such as cast titanium alloy.
A face insert 14 having increased surface roughness may comprise a layer of textured film co-cured with the plies of low FAW material, in which the layer of textured film forms a front surface of the face insert 14 instead of the metallic cap 18. The layer of textured film preferably comprises nylon fabric. Without the metallic cap 18, the mass of the face insert 14 is at least 15 grams less than a face insert of equivalent volume formed of the metallic material of the body 12 of the club head 10.
Typically, adhesion of the 3M® DP460 adhesive to a cast metallic surface is greater than to an untreated composite surface. Consequently, when the face structure fails on impact, the adhesive peels off the composite surface but remains bonded to the metallic surface. After treating a composite surface as described above, the situation is reversed [-] and the 3M® DP460 peels off the metallic surface but remains bonded to the composite surface.
The enhanced adhesion properties of this treatment contribute to an improved fatigue life for a composite golf club face. In a test, a club head having an untreated face insert 14 and a COR of about 0.847 endured about 250 test shots before significant degradation or failure occurred. In contrast, a similar club head having a treated face insert 14 and a COR of about 0.842 endured over 2000 shots before significant degradation or failure occurred.
Alternatively, the means for applying the composite texture improvement may be incorporated into the mold surface. By doing so, the textured area can be more precisely controlled. For simple face plate joining to the opening of a cast body, the texture can be formed in surfaces where shear and peel are the dominant modes of failure.
It should be appreciated from the foregoing that the present invention provides a club head 10 having a composite face insert (or face portion) 14 attached to a metallic body 12, forming a volume of at least 200 cc and providing superior durability and club performance. To that end, the face insert 14 comprises prepreg plies having a fiber areal weight (FAW) of less than 100 g/m2. The face insert 14 preferably has a thickness less than 5 mm and has a mass at least 10 grams less than a face insert of equivalent volume formed of the metallic material of the body 12 of the club head 10. The coefficient of restitution for the club head 10 is preferably at least 0.79.
Alternatively, the face insert 14 may comprise any non-metallic material having a density less than a metallic material of the body 12 along with a metallic cap 18 covering a front surface of the face insert 14 and having a rim 36. For example, the face insert 14 of the present invention may comprise a composite material, such as a fiber-reinforced plastic or a chopped-fiber compound (e.g., bulk molded compound or sheet molded compound), or an injection-molded polymer either alone or in combination with prepreg plies having low FAW. The thickness of the face insert 14 may be substantially constant or it may comprise a variation of at least two thicknesses, one being measured at a geometric center and another measured near a periphery of the face insert 14. In one embodiment, for example, an injection-molded polymer disk may be embedded in a central region of a plurality of low FAW prepreg plies. The total thickness of the face insert 14 may range between about 1 mm and about 8 mm, and preferably between about 2 mm and about 7 mm, more preferably between about 2.5 mm and about 4 mm, and most preferably between about 3 mm and about 4 mm.
In addition, the body 12 of a club head 10 in the present invention may be formed of a metallic material, a non-metallic material or a combination of materials, such as a steel skirt and sole with a composite crown, for example. Also, one or more weights may be located in or on the body 12, as desired, to achieve final performance characteristics for the club head 10.
In certain embodiments, a desirable CG-x location is between about 5 mm (heel side) and about −5 mm (toe side) along the CG x-axis 1005. A desirable CG-y location is between about 5 mm to about 20 mm along the CG y-axis 1007 toward the rear portion of the club head. Additionally, a desirable CG-z location is between about 12 mm to about 25 mm along the CG z-up axis 1009, as previously described.
In addition the striking insert 1112 includes a varying thickness and a thickened peripheral portion having a third thickness dimension 1110. The composite insert 1112 includes a first thickness 1111 at the thinnest region of the striking insert 1112 and a second thickness 1116 located in a central region of the striking insert 1112. The second thickness 1116 is the thickest dimension within the central region of the striking insert 1112. In one embodiment, the second thickness 1116 is greater than the first thickness 1111 and less than the third thickness 1110 of the peripheral portion. The third thickness 1110 located in a peripheral portion of the striking insert 1112 is greater than both the second thickness 1116 and the first thickness 1111. The peripheral region of the striking insert 1112 having the third thickness 1110 is attached to the ledge 1134.
In one embodiment, the first thickness 1111 can be between about 1.5 mm and about 2.0 mm, with a preferred thickness of about 2 mm or less. The second thickness 1116 can be between about 2 mm and about 3 mm and the third thickness 1110 is between about 3 mm and about 4.5 mm, or preferably about 3.5 mm to about 4.0 mm.
Alternatively, variable thickness configurations or inverted cone configurations can be implemented in the striking face 1112 as discussed in U.S. Pat. Nos. 6,800,038, 6,824,475, 6,904,663, and 6,997,820, all incorporated herein by reference.
In the examples described herein, a composite face insert can have a striking surface area in a range of about 2,700 mm2 to about 5,000 mm2. The unsupported surface area (surface area on the rear surface of the striking insert that is not engaged with a supporting surface) of the composite face insert can be within a range of about 300 mm2 to about 4,000 mm2, or preferably 450 mm2 to about 3,500 mm2. In some embodiments, the unsupported surface area is at least greater than about 2,000 mm2. The unsupported surface area is the portion of the composite insert that is defined by the first thickness 1111 and second thickness 1116 excluding the peripheral portion. The composite face thickness can be within a range of about 1 mm to about 8.0 mm, preferably about 2.5 to about 5 mm. In certain embodiments, the composite face thickness is less than about 4.0 mm. In embodiments having a thickened region, the thickened region surface area can range from about 230 mm2 to about 2,000 mm2.
The back wall 1214 includes a front engaging surface 1214a which provides support for the composite insert 1216 to be adhesively attached. The front engaging surface 1214a and the peripheral front opening wall 1210 create the front opening to receive the composite striking insert 1216. The front engaging surface 1214a is offset from the front surface 1230 of the club head by an offset distance 1226. The offset distance 1226 can be between about 1 mm and about 5 mm or preferably about 4 mm.
The offset distance 1226 is greater than or equal to the third thickness 1224 of the striking insert 1216 to enable the striking insert 1216 to sit within the front opening. The striking insert 1216 is located within the front opening so that the front striking insert 1216 surface is flush with the front portion surface 1230 of the club head body 1200. The interior gap cavity 1218 is located between the striking insert 1216 and the front engaging surface 1214a of the back wall 1214 and can be about 0.1 cc to about 20 cc. In one embodiment, the interior cavity is less than about 10 cc.
The interior cavity is entirely defined and surrounded by the striking insert 1216 and the rear back wall 1214 only. The back wall 1214 is in direct adhesive contact with the striking insert 1216 and supports the striking insert 1216. In other words, the thickened peripheral region 1212 of the striking insert is in direct contact with an interior surface of the back wall 1214.
It is critical that the central region of the striking insert 1216 is not capable of making direct contact with the back wall 1214 upon impact with the golf ball to avoid unwanted sound and unwanted performance effects. Therefore, a critical distance 1228 of about 1 mm or more is maintained between the front engaging surface 1214a and a rear surface 1216a of the striking insert 1216 at a maximum second thickness 1220 location.
The striking insert material, of the embodiments described herein, are made of the processes and materials described above but can also be a composite material as described in U.S. patent application Ser. No. 10/831,496 (now U.S. Pat. No. 7,140,974), Ser. Nos. 11/642,310, 11/825,138, 11/998,436, 11/823,638, 12/004,386, 12,004,387, 11/960,609, 11/960,610, and 12/156,947, which are incorporated herein by reference in their entirety. All of the composite inserts described herein can be made according to the processes and composite materials described within the above listed patents and patent applications. For example, in one embodiment, a composite face insert material having a fiber areal weight of less than 200 g/m2 is utilized. In another embodiment, a face insert material has a fiber areal weight less than 100 g/m2. In yet other embodiments, the face insert material has a fiber areal weight less than 150 g/m2.
For example, water jet cutting can be utilized to cut the composite face inserts from a sheet of composite material as described in the patents and patent applications incorporated by reference. In addition, the face insert can be formed by CNC cutting
Some examples of composites that can be used to form the components include, without limitation, glass fiber reinforced polymers (GFRP), carbon fiber reinforced polymers (CFRP), metal matrix composites (MMC), ceramic matrix composites (CMC), and natural composites (e.g., wood composites). The face insert may also be made of a thermoplastic material, as described herein. In certain embodiments, the composite face inserts described herein are made of a material having a density less than about 1.5 g/cc.
The lower leading edge zone 1346 is defined by the front opening wall 1310, the ledge plane 1338, the club face plane 1336, and the sole portion segment 1342. Within the lower leading edge zone 1346, an undercut or gap is avoided in order to lower the first leading edge groove centerline axis 1348 with respect to the ground 1301. The leading edge groove centerline axis 1348 is defined as the intersection of a bisectional plane 1352 and the club face plane 1336 at the centerline axis 1348 shown in
A low leading edge groove centerline axis 1348 is beneficial in allowing a golfer to make engaging contact with a ball sooner upon impact. In addition, a lower leading edge groove centerline axis 1348 may have additional benefits when a golfer mis-hits a ball by improving the quality of contact between the ball and the leading groove or lowest groove.
A horizontal plane 1350 contains the leading edge groove centerline axis 1348 and is parallel with the ground surface 1301. The height distance, h, between the horizontal plane 1350 of the leading edge groove axis 1348 and the ground surface 1301 is between about 4 mm and about 10 mm. In certain embodiments, the height distance, h, is between about 4 mm and about 8 mm or between about 4 mm and about 6 mm.
The front ledge surface 1406 intersects with the front opening wall 1408 at a rounded corner location 1416. The corner 1416 includes a radius of between about 0.1 mm and about 0.5 mm. In certain embodiments, the radius is at least about 0.30 mm or greater. A larger corner 1416 radius will avoid high stress concentrations that may result in material failure of the ledge 1418 after repeated use.
The rear bond gap distance, x, is located between the front ledge surface 1406 and the rear surface wall 1412. The rear bond gap distance, x, is measured along an axis that is perpendicular to the face plane toward a rear portion of the club head.
The side bond gap distance 1402 between the end wall 1410 and the front opening wall 1408 is between 0.1 mm and 0.5 mm, or about 0.3 mm or less. In one embodiment, the side bond gap distance 1402 and the rear bond gap distance, x, are filled with an adhesive epoxy to attach the composite insert 1404.
In certain embodiments, the rear bond gap distance, x, is equal to or greater than the side bond gap distance 1402. In some embodiments, the rear bond gap distance, x, is in accordance with the following inequality:
x≧0.2 mm Eq. 1
In the above inequality, the side bond gap distance 1402 is set at a distance of about 0.2 mm. If the rear bond gap distance, x, follows the inequality of Equation 1 described above, the composite face insert 1404 will be securely attached within the front opening. Without maintaining a rear bond gap distance, x, larger than the side bond gap distance 1402, the composite face insert 1404 may become loose after repeated impacts and bending.
However, the embodiment shown in
As shown, the side bond gap 1502 and step gap 1522 are filled with the adhesive 1514. The adhesive 1514 in the front portion parallel with the face plane to avoid unwanted bumps or sharp edges on the striking face.
In one embodiment, the total engineering gap 1520 is about 0.5 mm and the side bond gap distance 1502 is about 0.2 mm. As a result, the step gap 1522 is about 0.3 mm. The total engineering gap 1520 can be between about 0.2 mm and about 1 mm or preferably between about 0.2 mm and about 0.8 mm.
The engineering gap 1520 enables the composite face insert 1504 to be attached without maintaining a perfect side bond gap distance 1502 about the entire circumference of the face insert 1504. For example, the embodiment of
The above described engineering gap distance, side bond gap distance and step gap distance can be applied to any of the embodiments described herein. It is understood that the gaps shown in
The club head 1600 includes a front portion 1602, back portion 1606, a top line portion 1604, and a sole portion 1608. The club head 1600 further includes an upper back wall 1632, a lower back wall 1628, a badge 1630, a sole thickness 1622, a rear protrusion 1624, and filler material 1614. The badge 1630 is positioned above an upper edge 1626 and covers an aperture 1638 used for introducing the plug 1640 and filler material 1614 into the interior cavity of the club head 1600. The filler material 1614 and plug 1640 can be of the same configuration, material, and keying design as described in U.S. patent application Ser. No. 12/462,198, incorporated by reference herein, in its entirety.
In one embodiment, the filler material can be an expandable foam such as Expancel® 920 DU 40 which is an acrylic copolymer encapsulating a blowing agent, such as isopentane. A copolymer is greater than about 75 weight percent of the composition and the blowing agent is about 15-20 weight percent. The unexpanded particle size of the filler material can be between about 2 μm and about 90 μm depending on the context.
In one embodiment, the density of the filler material is between about 0.16 g/cc and about 0.19 g/cc. In certain embodiments, the density of the filler material is in the range of about 0.03 g/cc to about 0.2 g/cc, or about 0.04-0.10 g/cc. The density of the filler material impacts the COR, durability, strength, and filling capacity. In general, a lower density material will have less of an impact on the COR of a club head. The filler material can have a hardness range of about 15-85 Shore OO hardness or about 80 Shore OO hardness or less.
In one embodiment, the filler material is subject to heat for expansion of about 150° C.+/−10° C. for about 30 minutes. In some embodiments, the expansion of the filler material can begin at about 125° C. to about 140° C. A maximum expansion temperature range can be between about 160° C. to about 190° C. The temperature at which the expansion of the filler material begins is critical in preventing unwanted expansion after the club head is assembled. For example, a filler material that begins expanding at about 120° C. will not cause unwanted expansion when the club is placed in the trunk of a car (where temperatures can reach up to about 83° C.). Thus, a filler material that has a beginning expansion temperature of greater than about 80° C. is preferred.
Some other examples of materials that can be used as a filler material or plug material include, without limitation: viscoelastic elastomers; vinyl copolymers with or without inorganic fillers; polyvinyl acetate with or without mineral fillers such as barium sulfate; acrylics; polyesters; polyurethanes; polyethers; polyamides; polybutadienes; polystyrenes; polyisoprenes; polyethylenes; polyolefins; styrene/isoprene block copolymers; metallized polyesters; metallized acrylics; epoxies; epoxy and graphite composites; natural and synthetic rubbers; piezoelectric ceramics; thermoset and thermoplastic rubbers; foamed polymers; ionomers; low-density fiber glass; bitumen; silicone; and mixtures thereof The metallized polyesters and acrylics can comprise aluminum as the metal. Commercially available materials include resilient polymeric materials such as Scotchdamp™ from 3M, Sorbothane® from Sorbothane, Inc., DYAD® and GP® from Soundcoat Company Inc., Dynamat® from Dynamat Control of North America, Inc., NoViFlex™ Sylomer® from Pole Star Maritime Group, LLC, Isoplast® from The Dow Chemical Company, and Legetolex™ from Piqua Technologies, Inc. In one embodiment the filler material may have a modulus of elasticity ranging from about 0.001 GPa to about 25 GPa, and a durometer ranging from about 5 to about 95 on a Shore D scale. In other examples, gels or liquids can be used, and softer materials which are better characterized on a Shore A or other scale can be used. The Shore D hardness on a polymer is measured in accordance with the ASTM (American Society for Testing and Materials) test D2240.
In certain embodiments, the interior cavity of the club head 1600 can includes the plug 1640 for absorbing vibration. It is understood, that an embodiment without the plug 1640 is within the scope of the present description.
After the plug 1640 is frictionally engaged in a position, the filler material 1614 can be inserted into the cavity. In certain embodiments, the plug 1640 is a polymeric material.
In one embodiment, the plug 1640 material is a urethane or silicone material having a density of about 0.95 g/cc to about 1.75 g/cc, or about 1 g/cc. The plug 1640 can have a hardness of about 10 to about 70 shore A hardness. In certain embodiments, a shore A hardness of about 40 or less is preferred.
The filler material 1614 can be an expanding foam material that is expanded by a certain amount of heat as previously described. The filler material 1614 expands and fills a relatively large volume, greater than the volume occupied by the plug 1640.
In some embodiments, the volume of the cavity is between about 1 cc and about 200 cc, or preferably between about 10 cc and about 20 cc. For the purposes of measuring the cavity volume herein, the aperture 1638 is assumed to be removed from the back wall 1632 and an imaginary continuous back wall or substantially planar back wall is utilized to calculate the cavity volume.
In some embodiments, the filler material 1614 occupies about 50% to about 99% of the total club head cavity volume while the plug 1640 occupies between about 0% to about 20% of the total cavity volume. In specific embodiments, the plug 1640 occupies between about 0.1 cc and 1 cc with the remainder of the cavity volume being filled by the filler material 1614. It is understood that any of the embodiments described herein can be provided without a plug and filler material.
In order to achieve a desirable CG location, the filler material 1614 and plug 1640 must be lightweight. In certain embodiments, the total mass of the filler material 1614 and plug 1640 is less than about 5 g or between about 2 g and about 4 g. In one embodiment, the total weight of the filler material 1614 and the plug 1640 is 10 g or less or about 3 g or less. In certain embodiments, the total weight of the filler material 714 and plug 1640 is less than 2% of the total weight of the club head 1600 (excluding any badges, filler material/plug, and ferrule ring). In other embodiments, the total weight of the filler material 714 and plug 1640 is less than about 10% of the total weight of the club head 1600.
In some embodiments, the total weight of the filler material 1614 and plug 1640 is between about 1% and about 5% of the total weight of the club head (excluding the badges, filler material/plug, and ferrule ring). Thus, a desirable CG location is still attainable while improving the sound and feel of the golf club head. In certain embodiments, the plug 1640 can weigh about 0.5 g to about 1 g and the filler material 1614 can weigh about 5 grams or less. In some embodiments, the plug 1640 weighs about 0.7 g or less. In other embodiments, the plug 1640 can be equal to or heavier than the total filler material weight.
In yet other embodiments, the filler material 1614 and the plug 1640 have a combined weight of less than 20% of the total club head weight (excluding badges, filler material/plug, and ferrule ring). In one embodiment, the combined weight of the filler material 1614 and plug 1640 is less than 5%.
The filler material 1718 can be of the type already described above or can be a thermoplastic elastomer having a density of about 0.9 g/cc to about 1.20 g/cc.
In certain embodiments, the badges and composite face inserts, described herein, can be adhesively attached with epoxy or any known adhesive. For example, an epoxy such as 3M® DP460 can be used. It is possible for the badge 1830 to be mechanically attached to the back portion 1806 of the club head 1800.
After the hollow iron 1800 is filled with the filler material 1834, the badge 1830 is adhesively or mechanically attached to the back wall 1832 to cover or occlude the aperture to prevent filler material from leaving the cavity and also to achieve a desired aesthetic and while creating further dampening.
In some embodiments, the COR is greater than about 0.790. Preferably, the COR is at least 0.80 as measured according to the USGA Rules of Golf based on a 160 ft./s ball speed test and the USGA calibration plate. The COR can even be as high as 0.83.
In one embodiment, the body portion is made from 17-4 steel. However another material such as carbon steel (e.g., 1020, 1030, 8620, or 1040 carbon steel), chrome-molybdenum steel (e.g., 4140 Cr—Mo steel), Ni—Cr—Mo steel (e.g., 8620 Ni—Cr—Mo steel), or austenitic stainless steel (e.g., 304, N50, or N60 stainless steel, 410 stainless steel) can be used.
The components of the described components disclosed in the present specification can be formed from any of various suitable metals or metal alloys.
In addition to those noted above, some examples of metals and metal alloys that can be used to form the components of the parts described include, without limitation: titanium alloys (e.g., 3-2.5, 6-4, SP700, 15-3-3-3, 10-2-3, or other alpha/near alpha, alpha-beta, and beta/near beta titanium alloys), aluminum/aluminum alloys (e.g., 3000 series alloys, 5000 series alloys, 6000 series alloys, such as 6061-T6, and 7000 series alloys, such as 7075), magnesium alloys, copper alloys, and nickel alloys.
The body portion can include various features such as weighting elements, cartridges, and/or inserts or applied bodies as used for CG placement, vibration control or damping, or acoustic control or damping. For example, U.S. Pat. No. 6,811,496, incorporated herein by reference in its entirety, discloses the attachment of mass altering pins or cartridge weighting elements.
However, the composite face insert 1916 does not extend across the striking surface to a toe portion 1904 edge 1920 as shown in
Including a smaller percentage of composite face insert 1916 striking surface area can result in a significant reduction in manufacturing cost and composite material savings.
At least one advantage of the present invention is that a lightweight composite face insert will provide an improved CG club head location.
In addition, a certain engineering gap can be utilized to reduce the manufacturing time and expense associated with perfectly centering a composite face insert in a front opening of the golf club head.
At least another advantage of the embodiments described above, is that a rear back wall and badge can act to create an enclosed cavity behind the composite face so that the ledge and adhesive material used to bond the face insert to the club body is not visible to the user.
At least another advantage of the embodiments described is that a lightweight filler material arrangement is created allowing the center of gravity of the hollow iron construction to remain low while improving the sound and feel of the club during use.
The embodiments described herein conform with the USGA (United States Golf Association) Rules of Golf and Appendix II, 5c related to the Determination of Groove Conformance (issued in August 2008). For example, clubs having a loft of 25 degrees or higher meets the groove width, groove depth, groove separation, groove consistency, area limitations, and edge radius requirements set forth by the USGA. In the embodiments described herein, less than 50% of measured values of Area/(Width+Separation) are greater than 0.0030 in2/in and no single measured value of Area/(Width+Separation) value for any single groove is greater than 0.0032 in2/in.
With respect to a groove edge radius, the groove edges are in the form of a radius having an effective radius not less than 0.010″ as described by the two circles method described in the USGA rules. In addition, the effective radius is not greater than 0.020″. In the embodiments described, less than 50% of the upper groove edges or lower groove edges fails the two circles method subject to a 10 degree angular allowance as described in the USGA rules. No single groove edge protrudes more than 0.0003″ outside the outer circle.
In some examples, golf club heads are described with reference to a Coefficient of Restitution (COR) that is based on a ratio of a difference between ball speed and club head speed after impact to club head speed prior to impact. A COR of 1 corresponds to a maximum theoretical ball speed and a COR of 0 corresponds to a ball and club head moving together after impact. A COR of 0.83 or less is a suitable design goal for most club heads to insure compliance with USGA rules. Club heads can also be described with reference to a Characteristic Time (CT) that is associated with a time duration in which an object remains in contact with a club face. A CT of about 257 μs or less is a suitable design goal, corresponding to a current USGA limit of 239 μs plus a USGA tolerance of 18 μs. Thinner club faces tend to be associated with relatively larger COR and CT values.
Wood type golf club heads generally have dimensions selected to conform to USGA requirements. A wood type golf club head that conforms to USGA Rules can have dimensions no greater than about 71.1 mm from club sole to club crown, 127 mm from club toe to club heel, and 127 mm from club face to a backmost portion of the club head when held in a standard address position. In addition, total club head volume cannot exceed 470 cm3, including a 10 cm3 tolerance.
At club head/golf ball impact, a club striking face is deformed so that vibrational modes of the club head associated with the club crown, sole, or striking face are excited. The geometry of most golf clubs is complex, consisting of surfaces having a variety of curvatures, thicknesses, and materials, and precise calculation of club head modes may be difficult. Club head modes can be calculated using computer-aided simulation tools. For any manufactured club heads, and acoustic signal produced with ball/club impact can be evaluated as described below to select suitable club head characteristics for a desired club sound. Some club heads that are suitable for the following methods are described in U.S. patent application Ser. No. 11/960,609, filed Dec. 19, 2007.
Generally, club face acoustic modes at frequencies less than about 3 kHz, 3.5 kHz, or 3.8 kHz are associated with unpleasant sounds when used to strike a golf ball. Acoustic modes at these frequencies in the sole or crown can also cause a club to have an unpleasant sound. Conventional titanium or steel faces tend to exhibit such resonance frequencies due to the combination of material density, striking plate thickness, and elastic constant for the large club faces preferred by many golfers. However, with a composite striking plate, material properties are substantially changed so that face acoustic resonance frequencies can be raised to frequencies of 3.9 kHz, 4.0 kHz, 4.5 kHz, or higher, thereby providing golf clubs that have satisfactory sound characteristics. Because sound quality is particularly significant for driver type clubs, such clubs are discussed herein but other clubs such as fairway woods can be similarly configured, but these clubs have much less tendency to produce unpleasant sounds.
Referring to
Although the method 2000 is described with reference to measured values, in some examples, computer simulations using finite element analysis or other modeling methods can be used.
Representative data is illustrated in
Driver type test club head #2 in Table 1 below includes a significantly large face area of about 6978 mm2, a volume of about 460 cc and a head mass of about 203g. It should be noted that driver type test club heads #2, #3, #5, and #6 in Table 1 below are exemplary embodiments of the invention and incorporate a composite type face insert illustrated at least in
The table below lists measured lowest order striking surface (face) mode frequencies for a variety of driver type club heads. The damping constant provided in Table 1 is measured using ME'scope VES™ (Visual Engineering Series) software from Vibrant Technology Inc. version 5.1.2010.0709. The damping constant of club heads #2, #3, #5, #6, and #7 are at least greater than 0.232 due to the composite face providing a damping effect on a fully metallic body, crown, and sole construction. The damping constant for the composite face clubs range from 0.27 to 0.462 within these examples. The damping constant can be between about 0.25 or 0.3 to about 0.5 or 0.6 for a composite face insert club construction with a metallic body, crown, and sole. The damping increase is primarily due to the composite face construction in club heads 2, #3, #5, #6, and #7. In contrast, club head #1 illustrates a titanium face club head of similar face size and volume but having a significantly reduced about of damping at 0.232 due to the titanium face construction. In addition, club head #4 appears to have an increased damping constant of 0.639 due to the composite crown construction alone. The damping constant of club head #4 is not increased due to a composite face insert. In some cases, the club heads are provided for acoustic testing only, and do not correspond to USGA rules compliant clubs.
Representative data for club head #1 of the table above is illustrated in
Referring to
The loudness (sones) and acoustic amplitude (dB) data described throughout the present application is obtained through a specific test procedure. The loudness and amplitude are measured using a microphone positioned at exactly 64 inches directly above the ball at impact as measured from the outer surface of the ball to the outer surface of the microphone's sound recording portion. The microphone used in the test procedure is a G.R.A.S. Sound and Vibration pre-polarized microphone type 40AE. The microphone was connected to a Brüel & Kjaer Pulse™ noise and vibration analysis system (model 3160-B-140). The furthest distance of any impact location away from the center-face of the club was 11 mm as measured from the center face to the center point of the impact location. Post-processing of the recorded data was done using the Pulse™ Sound Quality software from Brüel & Kjaer.
Data for additional club heads are provided in additional figures.
As shown in
As shown in
All the club head samples listed in
y=0.0267x+81.667 Eq. 2
In Equation 2, y is the sones variable and x is the face size variable. Equation 2 defines an upper limit of a primary composite face insert zone. The primary composite face insert zone extends between a face size of 5,000 mm2 to 8000 mm2 on the x-axis and extends between about 175 sones up to the boundary of Equation 2 described above on the y-axis.
y=−0.44x+6300 Eq. 3
In Equation 3, the y variable is the primary face frequency mode of the face after an impact force and the x variable is the face size (mm2). In Equation 3, the slope value is negative. As the face size of a club is increased, the frequency appears to decrease as well.
As previously discussed, the composite face clubs all fall under 237 sones when impacted at center face. In addition to a low loudness characteristic, the composite face clubs generally have a face frequency greater than 3,800 Hz. When compared with titanium face clubs of similar face size that are less than 5,500 mm2 in
Equation 3 defines a lower limit of a primary composite face insert zone. The primary composite face insert zone extends between a face size of 5,000 mm2 to 8000 mm2 on the x-axis and extends between about 4,800 Hz down to the boundary of Equation 3 described above on the y-axis.
y=0.0005x+110 Eq. 4
y=0.0005x+108.5 Eq. 5
The first proposed limit is Equation 4 and the second proposed limit is Equation 5. In Equations 4 and 5, the y variable is the sound pressure level at impact (by Player A) and the x variable is the face size (mm2). In Equations 4 and 5, the slope value is positive. As the face size of a club is increased, the sound pressure level appears to increase as well.
The composite face clubs all fall under 113 dB when struck. When compared with titanium face clubs of similar face size that are greater than 6,000 mm2, the composite face clubs are at least 3 dB, 2.5 dB, 2 dB, 1.5 dB, or 1 dB lower. For composite face clubs (without a titanium cap) having a face size less than 5,500 mm2, the sound pressure values ranged from about 109 dB to about 112 dB. For composite face clubs (without a titanium cap) having a face size greater than 6,000 mm2, the sound pressure values ranged from about 109 dB to about 112 dB. An outlier data point 3102 occurring between 112 dB and 113 dB, at a face size between 5,500 mm2 and 6,000 mm2, is associated with a composite face insert having a titanium cap layer which is within the scope of this invention. It should be noted that the club head associated with data point 3102 is slightly higher in sound pressure levels than other composite face drivers without a titanium cap, but would still be well below the sound pressure levels found in ordinary titanium drivers (without a composite crown).
Equations 4 and 5 define an upper limit of a number of composite face insert zone. The primary composite face insert zone (including Ti cap embodiments) extends between a face size of 5,000 mm2 to 8000 mm2 on the x-axis and extends between about 109 dB up to the boundary of Equation 4 on the y-axis. An alternative primary composite face insert zone (excluding Ti cap embodiments) extends between a face size of 5,000 mm2 to 8000 mm2 on the x-axis and extends between about 109 dB up to the boundary of Equation 5 on the y-axis.
A narrower composite face insert zone can also be defined such as a zone having a y-axis limit between 109 dB up to the boundary of Equation 4 or 5 and a x-axis limit between a face size of 5,000 mm2 to 6,000 mm2, 5,500 mm2 to 7,000 mm2, 6,000 mm2 to 7,000 mm2, or 6,500 mm2 to 7,000 mm2.
A primary composite face insert zone extends between frequency of 3,800 Hz to 4,800 Hz on the x-axis and extends between about 105 dB up to 114 dB on the y-axis. An alternative primary composite face insert zone (that does not include composite crown clubs) extends between a frequency of 4,000 Hz to 4,800 Hz on the x-axis and extends between about 105 dB up to 114 dB on the y-axis.
A narrower composite face insert zone can also be defined such as a zone having a y-axis limit between 109 dB up to 110 dB or 111 dB and a x-axis limit between a frequency of 3,800 Hz to 4,000 Hz, 4,000 Hz to 4,400 Hz , 4,400 Hz to 4,600 Hz, or 4,600 Hz to 4,800 Hz. All the composite face club heads tested in
Thus, by varying striking face density, elastic constant, thickness, CT, COR, or other striking face property a suitable club head sound can be achieved. In some examples, club head sound levels in response to ball strikes at club head speeds of between 100-120 mph are less that 5 Pa (A-weighted) or less than 225 sones are suitable. Face resonance frequencies of 3.9 kHz, 4.2 kHz, or 4.4 kHz or greater are associated with suitable “pleasing” shot sounds. In some examples, a face thickness can be varied or a face thickness can be modified by local thinning or thickening at or near acoustic resonance nodes and/or antinodes.
While the above discussion is generally directed to improving sound characteristics (i.e., providing more pleasant sounds), in other examples club heads can be configured to produce unpleasant sounds or have other sound characteristics. Sound characteristics can be adjusted to provide a more aggressive or less pleasing sound by, for example, providing face resonances at frequencies less than about 3.5 kHz and/or amplitudes greater than about 225 sones or A-weighted pressures of greater than about 5 Pa. It will be appreciated that the examples disclosed herein are not to be taken as limiting the scope of the disclosure, and I claim all that is encompassed by the appended claims.
In certain embodiments, the total mass of the golf club head is between 185 g and 215 g or between 190 g and 210 or between about 194 g and 205 g. In similar embodiments, the volume of the golf club head as measured according to the USGA rules is between 390 cc and about 475 cc, or between about 410 cc and 470 cc, or between about 400 cc to about 475 cc, or greater than 400 cc. In certain embodiments, the coefficient of restitution is greater than 0.80 or 0.81 or between about 0.81 and 0.83 as measured according to the USGA rules of golf. Furthermore, the COR in the club heads of the present invention are between 0.80 and 0.81, or between 0.81 and 0.82, or between 0.82 and 0.83, or between 0.83 and 0.84. In some cases, a COR is achieved between 0.80 and 0.84. In addition, in some embodiments, the characteristic time is greater than 230 μs or 220 μs or between about 230 μs and 257 μs as measured according to the USGA rules.
The golf club head has a head origin defined as a position on the face plane at a geometric center of the face. The head origin includes an x-axis tangential to the face and is generally parallel to the ground when the head is in an address position. At the address position, a positive x-axis extends towards the heel portion and a y-axis extends perpendicular to the x-axis and is generally parallel to the ground. A positive y-axis extends from the face and through the rearward portion of the body and a z-axis extends perpendicular to the ground, to the x-axis and to the y-axis when the head is ideally positioned. Furthermore, a positive z-axis extends from the origin and generally upward.
In the metal-wood embodiments described herein, the “face size” or “face area” or “striking surface area” of “face size surface area” is defined according to a specific procedure described herein. A front wall extended surface 3306 is first defined which is the external face surface that is extended outward (extrapolated) using the average bulge radius (heel-to-toe) and average roll radius (crown-to-sole). The bulge radius is calculated using five equidistant points of measurement fitted across a 2.5 inch segment along the surface of the face as projected from the x-axis (symmetric about the center point). The roll radius is calculated by three equidistant points fitted across a 1.5 inch segment along the surface of the face as projected from the y-axis (also symmetric about the center point).
The front wall extended surface 3306 is then offset by a distance of 0.5 mm towards the center of the head in a direction along an axis that is parallel to the face surface normal vector at the center of the face. The center of the face is defined according to USGA “Procedure for Measuring the Flexibility of a Golf Clubhead”, Revision 2.0, Mar. 25, 2005.
A front wall plane is then defined as a plane which is tangent to the face surface at the geometric center of the face using the method defined in Section 6.1 of the USGA Procedure for Measuring the Flexibility of a Golf Clubhead (Revision 2.0 Mar. 25, 2005).
The hosel trimmed front wall profile shape curve 3322 is then projected onto the front wall plane, which is a two dimensional surface plane. Subsequently, the projection of the hosel trimmed front wall profile shape curve 3322 on the front wall plane is modified to find the final face area as defined herein. Specifically, in the projection plane at the first intersection point 3314 and the second intersection point 3320, a tangent line 3330,3324 is drawing tangent to the hosel trimmed front wall profile shape curve 3322 (as projected on the front plane) at the intersection points 3314,3320 until the tangent lines 3330,3324 intersect each other at a vertex 3326, as seen in
In certain embodiments, the striking surface has a surface area between about 4,500 mm2 and 6,200 mm2 and, in certain preferred embodiments, the striking surface is at least about 5,000 mm2 or between about 5,300 mm2 and 6,900 mm2 or between about 5,000 mm2 and 7,000 mm2. In some embodiments, the face size surface area includes a metallic material and a composite material which are both located on the front portion of the club head and are within a face size surface area region.
In order to achieve the desired face size, mass is removed from the crown material so that the crown material is between about 0.4 mm and 0.8 mm or less than 0.7 mm over at least 50% of the crown surface area.
In some embodiments, the golf club head can have a CG with a CG x-axis coordinate between about -5 mm and about 10 mm, a CG y-axis coordinate between about 15 mm and about 50 mm, and a CG z-axis coordinate between about −10 mm and about 5 mm. In yet another embodiment, the CG y-axis coordinate is between about 20 mm and about 50 mm. A positive CG y-axis is in a rearward direction of the club head, a positive CG x-axis is in a heel-ward direction of the club head, and a positive CG z-axis is in an upward or crown-ward direction on the club head.
The CG locations described are relative to a head origin coordinate system being provided such that the location of various features of the club head can be determined. The club head origin point is positioned at the geometric center of the striking surface which can be the location of ideal impact.
In certain embodiments, the club head height is between about 63.5 mm to 71 mm (2.5″ to 2.8″) and the width is between about 116.84 mm to about 127 mm (4.6″ to 5.0″). Furthermore, the depth dimension is between about 111.76 mm to about 127 mm (4.4″ to 5.0″). The club head height, width, and depth are measured according to the USGA rules. In similar embodiments, the moment of inertia about the CG x-axis (toe to heel), the CG y-axis (back to front), and CG z-axis (sole to crown) is defined. In certain implementations, the club head can have a moment of inertia about the CG z-axis, between about 450 kg·mm2 and about 650 kg·mm2, and a moment of inertia about the CG x-axis between about 300 kg·mm2 and about 500 kg·mm2, and a moment of inertia about the CG y-axis between about 300 kg·mm2 and about 500 kg·mm2.
In view of the many possible embodiments to which the principles of the disclosed invention may be applied, it should be recognized that the illustrated embodiments are only preferred examples of the invention and should not be taken as limiting the scope of the invention. It will be evident that various modifications may be made thereto without departing from the broader spirit and scope of the invention as set forth. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.
This application claims the benefit of U.S. Provisional Application No. 61/428,547, filed on Dec. 30, 2010, which is incorporated herein by reference in its entirety. The following disclosure is provided with reference to U.S. patent application Ser. No. 11/960,609, filed Dec. 19, 2007, which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61428547 | Dec 2010 | US |
