Golf club head

Abstract

To provide a fairway wood type golf club head which has a steel structure and achieves low CG without changing the conventional external dimensions of the fairway wood type golf club head.SOLUTION: Provided is golf club head formed of an alloy of steel that is capable of improving the center of gravity (CG) location while maintaining traditional external dimensions of the golf club head. More specifically, the golf club head in accordance with the present invention achieves a relatively low CG while maintaining traditional external dimensions by reducing the amount of mass contributed by a crown, a striking face 1220, and a hosel, and strategically reallocating this mass within and / or proximate the sole of the golf club head.SELECTED DRAWING: Figure 13

Description

[Technical field]

[0001] The present invention relates generally to golf club heads, and more specifically to steel bodied fairway woods with a low center of gravity (CG). [Background technology]

[0002] The rules of golf allow a golfer to carry 14 golf clubs. In an ideal world, each golf club serves its own purpose. For example, drivers are primarily used to hit the golf ball off a tee, preferably achieving great distances. Fairway woods and hybrid clubs are used to hit the ball farther, but not as far as a driver. Fairway woods and hybrids are often used off a tee when a golfer wants to hit the ball straighter or shorter than a driver. Fairway woods and hybrids are also often used directly off the ground without a tee. Iron-type golf clubs are used to hit the ball straighter, shorter, and with an emphasis on accuracy.

[0003] Each of these different types of golf clubs is specifically designed to be maximally effective for a particular purpose. Fairway woods and hybrids require a unique balance of performance and aesthetics because they require distance and accuracy not only off the tee but also when hit off the ground without a tee.

[0004] Given the versatility of fairway woods and hybrids, it is desirable to have the center of gravity located low to the ground to facilitate launching a golf shot into the air, especially for shots that are hit directly from the ground without the use of a tee. Fairway woods and hybrids are often made primarily from steel alloys. Traditionally, the center of gravity of a fairway wood or hybrid can be lowered by utilizing one of several undesirable design features.

[0005] For example, the crown peak height of a golf club can be lowered to lower the center of gravity. Although lowering the crown peak height of a golf club can lower the center of gravity, the associated design tradeoffs are undesirable. Lowering the crown peak height does not result in an aesthetically pleasing golf club head. Specifically, the golf club head will be less voluminous, or at least will look smaller, than a conventional golf club head, which can make a golfer feel less confident when preparing to hit a golf shot.

[0006] Similarly, the height of the striking face of the golf club (e.g., the radius from the ground to the top face) may also be reduced, which, as noted above, not only reduces the aesthetic look of the golf club, but also makes the golf club more difficult to hit by physically reducing the size of the striking face.

[0007] Additionally, golf club heads may incorporate various materials to manipulate the location of the CG. For example, the crown of a golf club may be formed from any of a variety of materials, such as titanium or composites that are less dense than steel. Although incorporating various materials is useful for manipulating the CG of a golf club head, it is costly and involves many potential manufacturing challenges associated with joining different materials.

[0008] Therefore, there is a demand for a fairway wood type golf club head that has a steel structure and achieves a low CG without changing the conventional outer dimensions of a fairway wood type golf club head. Summary of the Invention

[0009] One aspect of the invention is a golf club head including a striking face defining a face center, a crown, a sole opposite the crown, a heel, a toe opposite the heel, and a hosel adjacent the heel and configured to couple the golf club head to a shaft, each of the striking face, the crown, the sole, the heel, the toe, and the hosel being constructed from an alloy of steel, an X-axis being defined as a horizontal axis tangent to the face center of the striking face and having a positive direction toward the heel of the golf club head, a Y-axis being a vertical axis orthogonal to both the X-axis and the Y-axis and having a positive direction toward a front face of the golf club head, the X-axis being a horizontal axis tangent to the face center of the striking face and having a positive direction toward the heel of the golf club head, and a Y-axis being a vertical axis orthogonal to both the X-axis and the Y-axis and having a positive direction toward a front face of the golf club head, the X-axis being a horizontal axis tangent to the face center of the striking face and having a positive direction toward the heel of the golf club head, the Y-axis being a vertical axis tangent to the face center of the striking face and having a positive direction toward the crown of the golf club head, the Y-axis being a vertical axis tangent to the face center of the striking face and having a positive direction toward the front face of the golf club head, the X-axis being a horizontal axis tangent to the face center of the striking face and having a positive direction toward the heel of the golf club head, the Y-axis being a vertical axis tangent to the face center of the striking face and having a positive direction toward the front face ... an origin of the Y-axis and the Z-axis is centered at a center of gravity (CG) of the golf club head, the volume of the golf club head is about 100 cc to about 200 cc, the crown has a minimum crown thickness between about 0.3 mm to about 0.6 mm, the sole has a maximum sole thickness, the peak crown height of the golf club head is greater than about 35.0 mm, a radial measurement from the ground to a top face of the golf club head is about 31.0 mm or greater, a CG-Yg of the golf club head is the distance from the ground to the CG along the y-axis that is less than about 16.0 mm, and a ΔYccg of the golf club head is between about 22.0 mm to about 28.0 mm, and the ΔYccg is defined by the following equation: ΔYccg = Peak crown height (mm) - CG - Yg (mm) The golf club head has a maximum sole thickness to minimum crown thickness ratio of about 4.0 or greater, the maximum sole thickness to minimum crown thickness ratio being defined by the following formula: Maximum sole thickness to minimum crown thickness ratio = Maximum sole thickness (mm) / minimum crown thickness (mm) The mass of the golf club head is greater than about 45% of the total mass of the golf club head below an XZ plane established at a vertical height from the ground equal to 25% of the peak crown height measurement, the mass of the golf club head is greater than about 38% of the total mass of the golf club head below an XZ plane established at a vertical height from the ground equal to 20% of the peak crown height measurement, the mass of the golf club head is greater than about 27% of the total mass of the golf club head below an XZ plane established at a vertical height from the ground equal to 15% of the peak crown height measurement, and the mass of the golf club head is greater than about 12% of the total mass of the golf club head below an XZ plane established at a vertical height from the ground equal to 10% of the peak crown height measurement.

[0010] In accordance with another aspect of the present invention, a golf club head includes a striking face defining a face center, a crown, a sole opposite the crown, a heel, a toe opposite the heel, and a hosel adjacent the heel and configured to couple the golf club head to a shaft, each of the striking face, the crown, the sole, the heel, the toe, and the hosel being comprised of an alloy of steel, an X-axis being defined as a horizontal axis tangent to the face center of the striking face and having a positive direction toward the heel of the golf club head, and a Y-axis being defined as a horizontal axis tangent to the face center of the striking face and having a positive direction toward the heel of the golf club head. a Z-axis having a positive direction toward the center of the golf club head, perpendicular to both the X-axis and the Y-axis, and having a positive direction toward the front surface of the golf club head; origins of the X-axis, the Y-axis, and the Z-axis are centered on a center of gravity (CG) of the golf club head; a volume of the golf club head is about 100 cc to about 200 cc; a minimum crown thickness of the crown is about 0.3 mm to about 0.6 mm; the sole has a maximum sole thickness; a maximum sole thickness to minimum crown thickness ratio of the golf club head is about 4.0 or more, and the maximum sole thickness to minimum crown thickness ratio is defined by the following formula: Maximum sole thickness to minimum crown thickness ratio = Maximum sole thickness (mm) / minimum crown thickness (mm)

[0011] In accordance with another aspect of the present invention, a golf club head includes a striking face defining a face center, a crown, a sole opposite the crown, a heel, a toe opposite the heel, and a hosel adjacent the heel and configured to couple the golf club head to a shaft, each of the striking face, the crown, the sole, the heel, the toe, and the hosel being comprised of an alloy of steel, an X-axis is defined as a horizontal axis tangent to the face center of the striking face and having a positive direction toward the heel of the golf club head, a Y-axis is defined as a Z-axis that is orthogonal to both the X-axis and the Y-axis and has a positive direction toward a front surface of the golf club head, and the X-axis, Y-axis, and and the origin of the Z-axis is centered at the center of gravity (CG) of the golf club head, the volume of the golf club head is between about 100cc and about 200cc, the crown has a minimum crown thickness between about 0.3mm and about 0.6mm, the sole has a maximum sole thickness, the mass of the golf club head below an XZ plane set at a vertical height from the ground plane equal to 25% of the peak crown height measurement, the mass of the golf club head below an XZ plane set at a vertical height from the ground plane equal to 15% of the peak crown height measurement is greater than about 45% of a total mass of the golf club head, and the mass of the golf club head below an XZ plane set at a vertical height from the ground plane equal to 15% of the peak crown height measurement is greater than about 27% of a total mass of the golf club head. According to another aspect of the invention, the golf club head has a maximum face thickness to sole return thickness ratio between about 1.70 and about 2.18, the maximum face thickness to sole return thickness ratio being defined as follows: Maximum face thickness to sole return thickness ratio = Maximum face thickness T f1 / Sole return thickness (T R )

[0012] In accordance with another aspect of the present invention, the striking face includes a sole return.

[0013] In accordance with another aspect of the invention, the striking face comprises a variable face thickness profile further having a crown-biased thickened transition portion, an upper transition portion having an upper transition slope, and a lower transition portion having a lower transition slope, the upper transition slope being greater than the lower transition slope.

[0014] In accordance with another aspect of the invention, the aspect ratio of the crown bias thickened transition portion is greater than about 5.

[0015] In accordance with another aspect of the invention, the sole return has an initial front thickness that is greater than the intermediate thickness, and the sole return has a terminal thickness that is greater than the intermediate thickness.

[0016] These and other features, aspects, and advantages of the present invention will become better understood with reference to the following drawings, description, and claims. [Brief description of the drawings]

[0017] The above and other features and advantages of the present invention will become apparent from the following description of the invention as illustrated in the accompanying drawings, which are incorporated herein and form a part of the specification, and further serve to explain the principles of the invention and to enable one skilled in the art to make or use the invention. [Figure 1] FIG. 1 of the accompanying drawings shows a perspective view of a golf club head in accordance with an exemplary embodiment of the present invention. [Diagram 2] FIG. 2 of the accompanying drawings shows a crown side view of a golf club head in accordance with one embodiment of the present invention. [Diagram 3] FIG. 3 of the accompanying drawings shows a face side view of a golf club head in accordance with one embodiment of the present invention. [Figure 4]FIG. 4 of the accompanying drawings shows a toe-side cross-sectional view along a vertical plane along the Z axis passing through the face center of a golf club head according to one embodiment of the present invention. [Figure 5A] FIG. 5A of the accompanying drawings shows a perspective view of the sole of a golf club head in accordance with one embodiment of the present invention. [Figure 5B] FIG. 5b of the accompanying drawings shows a perspective view of the sole of a golf club head in accordance with an alternative embodiment of the present invention. [Figure 6] FIG. 6 of the accompanying drawings illustrates an exploded perspective heel side view of a golf club head in accordance with an alternative embodiment of the present invention. [Figure 7] FIG. 7 of the accompanying drawings illustrates an exploded perspective toe side view of a golf club head in accordance with an alternative embodiment of the present invention. [Figure 8] FIG. 8 of the accompanying drawings is a cross-sectional view of a golf club head in accordance with an alternative embodiment of the present invention. [Figure 9] FIG. 9 of the accompanying drawings illustrates an exploded heel side perspective view of a golf club head in accordance with an alternative embodiment of the present invention. [Figure 10] FIG. 10 of the accompanying drawings illustrates an exploded perspective toe side view of a golf club head in accordance with an alternative embodiment of the present invention. [Figure 11] FIG. 11 of the accompanying drawings shows a cross-sectional view of a golf club head in accordance with an alternative embodiment of the present invention. [Figure 12] FIG. 12 of the accompanying drawings illustrates a heel side exploded view of a golf club head in accordance with yet another embodiment of the present invention. [Figure 13] FIG. 13 of the accompanying drawings illustrates a heel side perspective view of a striking face in accordance with yet another embodiment of the present invention. [Figure 14] FIG. 14 of the accompanying drawings illustrates a rear view of a striking face in accordance with yet another embodiment of the present invention. [Figure 15] FIG. 15 of the accompanying drawings illustrates a cross-sectional view of yet another striking face of the present invention taken along section line A-A' shown in FIG. Detailed Description of the Invention

[0018] The following detailed description sets forth the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, the scope of which is best defined by the appended claims.

[0019] Various features of the invention are described below, each of which can be used independently of one another or in combination with other features. However, a single inventive feature may not address some or all of the problems discussed above, or may address only one of the problems discussed above. Furthermore, one or more of the problems discussed above may not be fully addressed by any of the features described below.

[0020] Before beginning the discussion of the golf club head 100 of the present invention and its performance criteria, it is useful to point out here that the following discussion is based on a coordinate system 101 and measurement axes that are important to the proper evaluation of the performance variables detailed below. Thus, while the specific names given to the measurements below are important to the understanding of the present invention, it is important to realize that the nomenclature should not be viewed in a vacuum. Rather, the significance of the numbers shown below must be understood in the context of how the coordinate system relates to the golf club head itself. To provide sufficient information and avoid ambiguity, each of the following figures that reference the golf club head 100 is accompanied by a reference coordinate system.

[0021] In accordance with the above, and to establish a reference coordinate system for the following description, FIG. 1 of the accompanying drawings shows a coordinate system 101 used to define various measurements and performance figures of the present invention. The X-axis used in this discussion refers to an axis horizontal to the striking face from a heel-to-toe direction. The Y-axis used in this discussion refers to a vertical axis passing through the club from a crown-to-sole direction. The Z-axis used in this discussion refers to a horizontal axis horizontal in a front-to-back direction. Alternatively, the X-axis is defined as a horizontal axis tangent to the geometric center of the striking face with the positive direction being toward the heel of the golf club head, the Y-axis is a vertical axis perpendicular to the X-axis with the positive direction being toward the top of the golf club head, and the Z-axis is an axis perpendicular to both the X-axis and the Y-axis with the positive direction being toward the front of the golf club head. The XYZ coordinate system 101 described above shall remain the same in all the following descriptions.

[0022] FIG. 1 of the accompanying drawings shows a perspective view of a golf club head 100 according to one embodiment of the present invention. While in this perspective view shown in FIG. 1, the golf club head 100 may appear similar to other golf club heads, it will be appreciated from subsequent figures and their descriptions that the particular dimensions and material properties of the golf club head 100 provide unique performance characteristics consistent with the present invention. FIG. 1 shows a golf club head 100 having a striking face 120, a crown 106, a sole 108 opposite the crown 106, a heel 104, a toe 102 opposite the heel 104, a hosel 124 adjacent the heel for connecting the golf club head 100 to a shaft (not shown), and a skirt 112 connecting the crown 106 and the sole 108 and extending from the heel 104 adjacent the striking face 120 to the toe 102 adjacent the striking face 120. The striking face 120 has a face center 122. The face center 122 shown and referred to in this invention relates to the geometric center of the striking face 120 of the golf club head 100 described above, as measured by the face center template provided by the USGA, as is commonly known to those skilled in the golf club art.

[0023] In this embodiment of the invention, the golf club head 100, and in particular the striking face 120, crown 106, sole 108, skirt 112, toe 102, heel 104, and hosel 124, are generally formed from an alloy of steel having a density between about 7.75 g / cc and about 8.05 g / cc. Preferably, the golf club head 100 is formed by a casting process known in the art. It is also within the scope and content of the invention for at least a portion of the golf club head 100 to be formed by other known processes, including stamping, forging, and rolling.

[0024] It is also within the scope of this invention for the striking face 120, crown 106, sole 108, skirt 112, toe 102, heel 104, and hosel 124 to be formed entirely from an alloy of steel having a density between about 7.75 g / cc and about 8.05 g / cc.

[0025] It is within the scope and content of the present invention for the striking face 120 to be formed integrally with other portions of the golf club head 100 or, alternatively, as a separate piece that is subsequently joined to other portions of the golf club head 100. If the striking face 120 is formed as a separate piece, it may be formed of high strength steel and joined to the golf club head 100 by any suitable method, including welding, brazing, adhesives, and mechanical fasteners. Exemplary high strength steel materials for forming the striking face 120 include custom 465 stainless steel, custom 475 stainless steel, 300 stainless steel, and 301 stainless steel, although the invention is not limited in this respect.

[0026] The golf club head 100 may generally have a volume of from about 100 cc to about 200 cc, more preferably from about 120 cc to about 190 cc, and most preferably from about 140 cc to about 185 cc.

[0027] The golf club head 100 may generally have a total mass of about 175 g to about 275 g, more preferably about 190 g to about 250 g, and most preferably about 200 g to about 225 g.

[0028] 2 is a crown diagram of golf club head 100. To illustrate more specific features of golf club head 100, accompanying FIG. 2 is provided to provide additional insight into some of the specific characteristics of golf club head 100 that are important for quantifying the performance enhancements of golf club head 100. Accompanying FIG. 2 illustrates the location of CG 110 along the XZ plane on coordinate system 101. Although the details of the location of CG 110 will be explained in more detail with respect to the inertial characteristics of golf club head 100, generally speaking, the golf club head 100 of the present invention includes a CG 110 location that is strategically located within golf club head 100 to provide the most advantageous results.

[0029] More specifically, in the present exemplary embodiment of the invention, CG 110 is positioned rearward from a shaft axis 115 extending along the XY plane, a distance CG-C 114 typically between about 9 mm and about 16 mm, more preferably between about 10 mm and about 15 mm, and most preferably between about 11 mm and about 14 mm, all measured rearward from shaft axis 115 along the Z axis as indicated by coordinate system 101.

[0030] It should be noted that the strategic location of the CG 110 rearward along the Z-axis is critical to the proper functionality of the golf club head 100 of the present invention. If the CG 110 is positioned too far forward, the inertia of the golf club head 100 may be reduced and may result in a less than optimal amount of backspin upon contact with the golf ball, which may not produce the desired results. Conversely, however, if the CG 110 is positioned too far back, the golf club head 100 may generate excessive spin, which may not produce the desired results. Thus, it can be seen that the importance of the location of the CG 110 rearward along the Z-axis of the shaft axis 115 requires a delicate balance within a very specific range of values, outside of which the performance of the golf club head 100 may be significantly degraded.

[0031] FIG. 3 of the accompanying drawings is a face side view of a golf club head 100. FIG. 3 illustrates several additional dimensional measurements that are important to the proper functioning of the present invention. Specifically, FIG. 3, in addition to illustrating the basic components of the golf club head 100 previously shown, introduces another measurement of the position of the CG 110 from the ground G along the XY plane depicted in coordinate system 101. More specifically, FIG. 3 illustrates the CG 110 measurement, which is the distance measured vertically along the Y axis from the ground G to the CG 110, and for purposes of this description will be referred to as CG-Yg 116. The CG-Yg 116 of the golf club head 100 may generally be less than about 16.0 mm, more preferably between about 11.0 mm and about 15.0 mm, and most preferably between about 12.0 mm and about 14.5 mm.

[0032] In addition to showing the all-important CG-Yg 116 measurement of the golf club head 100, Figure 3 of the accompanying drawings also shows the peak crown height 117 measurement, which is the vertical distance along the Y axis from the ground G to the apex of the crown 106 when the golf club head 100 is held in a normal address position. The peak crown height 117 measurement may generally be greater than about 35.0 mm, preferably between about 36.0 mm and about 43.0 mm, and most preferably between about 37.0 mm and about 41.0 mm.

[0033] FIG. 3 of the accompanying drawings also shows a ground to top face radius measurement 118, which is the vertical distance along the Y axis from the ground G to the point where the striking face 120 transitions into the crown 106. More specifically, the ground to top face radius measurement 118 is the vertical distance along the Y axis from the ground G to the point where the golf club head 100 deviates from the roll radius of the striking face 120. It is within the scope and content of the present invention to measure the ground to top face radius measurement 118 directly above the face center 122 or at the highest point on the striking face 120 along the Y axis. Preferably, the ground to top face radius measurement 118 is measured directly above the face center 122. The ground to top face radius measurement 118 may generally be greater than or equal to about 31.0 mm, more preferably between about 31.0 mm and about 37.0 mm, and most preferably between about 33.0 mm and about 35.0 mm.

[0034] Figure 3 of the accompanying drawings also shows a ΔYccg 119 measurement, which is the vertical distance from CG 110 to the apex of the crown 106 along the Y axis. In other words, the ΔYccg measurement 119 is the difference between the crown peak height 117 measurement and the CG-Yg 116 measurement. The ΔYccg 119 measurement is described in more detail below.

[0035] With the location of the CG 110 of the golf club head 100 defined, another important feature relevant to the present invention will now be described in more detail regarding the moment of inertia (MOI) of the golf club head 100. The MOI of a golf club head generally represents the ability of the golf club head to resist twisting when the golf club head impacts an object that is not in line with the location of the aforementioned CG. More specifically, the MOI of a golf club head relates to the ability of the golf club head to resist twisting relative to the location of the CG.

[0036] As is well known in the art, the MOI of the golf club head 100 can be broken down into several unique components that are typically related to the ability of the golf club head 100 to resist rotation along different axes relative to the location of the CG 110, with the origin of three axes coinciding with the location of the CG 110 of the golf club head 100. The three axes of rotation to which the MOI is typically referenced correspond to a coordinate system 101 shown throughout the drawings, where MOI-X is measured about an X-axis that passes through the location of the CG 110, MOI-Y is measured about a Y-axis that passes through the location of the CG 110, and MOI-Z is measured about a Z-axis that passes through the location of the CG 110.

[0037] The golf club head 100 of the present invention generally has a swing resistance of approximately 80 kg-mm 2 More preferably, about 90 kg-mm 2 ~ approx. 140kg-mm 2 , and most preferably about 100 kg-mm 2 ~ approx. 130kg-mm 2 However, all of these do not depart from the scope and content of the present invention.

[0038] The golf club head 100 of the present invention generally has a swing resistance of approximately 220 kg-mm 2 More preferably, about 230 kg-mm 2 Larger, most preferably about 240 kg-mm 2 A larger MOI-Y may be provided without departing from the scope and content of the present invention. In other words, the golf club head 100 of the present invention is generally capable of a high MOI-Y value while maintaining a relatively low CG 110 position.

[0039] The golf club head 100 of the present invention generally has a swing resistance of approximately 160 kg-mm 2 More preferably, about 160 kg-mm 2 ~about 220kg-mm 2 , and most preferably about 170 kg-mm 2 ~About 210kg-mm 2and this does not depart from the scope and content of the present invention.

[0040] While the above MOI values ​​are not necessarily new in the world of golf club head 100 design, the ability to maintain those values ​​while maintaining the location of CG 110 as described above, particularly the relative values ​​of CG-Yg 116 and CG-C 114, distinguishes this invention. This invention allows for a lower CG in a steel golf club head than ever before while maintaining traditional fairway wood dimensions such as volume, peak crown height, and radius height from the ground to the top face.

[0041] 4 is a toe-side cross-sectional view taken along a vertical plane extending along the Z axis through face center 122. As will be described below, FIG. 4 illustrates several additional important features of the present invention.

[0042] 4, several dimensions of the golf club head 100 are more clearly shown which illustrate further inventive features of the present invention. According to an exemplary embodiment of the present invention, the minimum crown thickness Tc of the crown 106 is less than the thickness Tc of a conventional cast steel crown (which is typically greater than 0.6 mm). According to the present exemplary embodiment, the minimum crown thickness Tc of the crown 106 is preferably between about 0.3 mm and about 0.6 mm, more preferably between about 0.35 mm and about 0.5 mm, and most preferably about 0.4 mm.

[0043] Additionally, a portion of the crown 106 may have a substantially constant thickness within + / - 10% of the minimum crown thickness Tc of the crown 106. For purposes of this description, the surface area of ​​the crown 106 is defined by the portion of the golf club head 100, excluding the hosel 124, that is visible from directly above the golf club head 100 when the golf club head 100 is in a normal address position. According to one embodiment of the present invention, at least about 40% of the total surface area of ​​the crown 106 may have a substantially constant thickness within + / - 10% of the minimum crown thickness Tc, preferably at least about 60% of the total surface area of ​​the crown 106 may have a substantially constant thickness within + / - 10% of the minimum crown thickness Tc, and most preferably at least about 75% of the total surface area of ​​the crown 106 may have a substantially constant thickness within + / - 10% of the minimum crown thickness Tc.

[0044] By reducing the thickness of the crown 106 as described above, the total mass of the crown 106 may be reduced. The mass saved by reducing the thickness of the crown 106 may be redistributed to any mass throughout the golf club head 100, such as any mass in and / or near the sole 108. The golf club head 100 of the present invention having the crown 106 as described above has a CG-Yg 116 measurement that is at least 0.3 mm lower than conventional golf club heads having a minimum crown thickness of more than 0.6 mm. Although at first glance a reduction in the CG-Yg 116 measurement of 0.3 mm may not seem like a big deal, the present invention utilizes several inventive features to achieve a lower CG-Yg 116 measurement than other known golf club heads having conventional dimensions as described above and formed from steel.

[0045] FIG. 4 illustrates another feature that further reduces the CG-Yg116 measurement of the golf club head 100. It is well known that striking faces have different thicknesses at different points on the striking face surface, known as variable face thickness (VFT). In an exemplary embodiment of the present invention, the maximum face thickness Tf occurs near the face center 122 and is preferably less than about 2.0 mm, more preferably less than about 1.95 mm, and most preferably about 1.9 mm. Traditionally, a steel striking face has a maximum face thickness Tf greater than about 2.0 mm. The golf club head 100 of the present invention having a striking face 120 as described above may have a CG-Yg116 measurement at least 0.1 mm lower than a conventional golf club head having a maximum face thickness Tf of at least 2.0 mm. The maximum face thickness Tf is the distance between the outer and inner surfaces of the striking face measured perpendicular to the loft plane L, which is the plane tangent to the face center 122 of the striking face 120. Although a 0.1 mm reduction in CG-Yg 116 may seem small at first glance, the present invention relies on several inventive features to make the CG-Yg 116 lower than other known golf club heads having conventional dimensions as described above and formed from steel.

[0046] 4 also shows the loft angle θ, which is the angle between the loft plane L and the XY plane. The loft angle θ is preferably between about 12 degrees and about 25 degrees.

[0047] 4 also illustrates a unique hosel 124 structure for use with an adjustable shaft sleeve (not shown), as is known in the art. The hosel 124 is adapted to adjustably couple the golf club head 100 to a shaft (not shown). The hosel 124 includes an upper hosel portion 124A adjacent the crown 106 and a lower hosel portion 124B adjacent the sole 108. The upper hosel portion 124A is configured to receive the adjustable shaft sleeve (not shown) to allow adjustment of the orientation (lie, loft, and face angle) of the golf club head 100. The lower hosel portion 124B is configured to receive a fastener (not shown) for connecting the shaft sleeve (not shown) to the golf club head 100, as is well known in the art. Unlike conventional structures, the portion of the hosel 124 between the upper hosel portion 124A and the lower hosel portion 124B is open to the interior of the golf club head 100.

[0048] The total mass of the hosel 124, including the separate upper hosel portion 124A and the separate lower hosel portion 124B, may be reduced as compared to a conventional hosel as described above, particularly the portion of the mass of the hosel 124 above the CG 110 location. The mass savings associated with the hosel 124 as compared to a conventional hosel design may be redistributed as any mass throughout the golf club head 100, such as any mass in and / or near the sole 108. The golf club head 100 of the present invention having the hosel 124 as described above will exhibit a CG-Yg 116 measurement that is at least 0.35 mm lower than a conventional golf club head having a conventional hosel adapted to accept a conventional adjustable shaft sleeve. As described above, although a 0.35 mm reduction in the CG-Yg 116 measurement may seem small at first glance, the present invention relies on several inventive features to achieve a lower CG-Yg 116 measurement than other known golf club heads formed of steel and having conventional dimensions as described above.

[0049] FIG. 4 also shows an optional weight pocket 130 located near the sole 108 of the golf club head 100. The weight pocket 130 is adapted to receive a weight member (not shown). It is understood that the structure of the weight member is not critical to the present invention and the weight member may take the form of known structures and modifications of known structures. The weight member may be formed from any number of materials having a density less than, equal to, or greater than the remainder of the golf club head 100. Preferably, the weight member may be formed from an alloy of steel having a density substantially equal to the remainder of the golf club head 100. Alternatively, the weight member may include a material having a density greater than the steel portion of the golf club head 100, such as at least one of tungsten, molybdenum, tantalum, hafnium, and niobium. It is also within the scope of the present invention for the weight member to include a material having a density less than the steel portion of the golf club head 100, such as at least one of titanium, aluminum, plastic, and composite materials. Mass saved by reducing the minimum thickness of the crown 106, reducing the maximum thickness of the striking face 120, and modifying the construction of the hosel 124 to open up into the interior of the golf club head 100 may be allocated as any mass in and / or near the sole 108. For example, any mass may be allocated within the sole 108, within a weight member, or within any portion of the golf club head 100 below the CG 110 to minimize the value of the CG-Yg 116 measurement while maintaining the conventional dimensions and other emphasized inertia values ​​of the golf club head 100.

[0050] As shown in FIG. 4, the majority of the sole 108 has a substantially constant thickness. Moreover, the portion of the sole 108 having a substantially constant thickness rearward of the weight pocket 130 is substantially equal to the maximum sole thickness Ts. It should be noted that for purposes of determining the maximum sole thickness Ts, the portions of the sole 108 defining and adjacent the weight pocket 130 and the portions of the sole within about 10 mm of the skirt 112 are not considered. The maximum sole thickness Ts is preferably about 1.6 mm or greater, more preferably about 1.8 mm or greater, and most preferably about 1.9 mm or greater.

[0051] According to one embodiment of the invention, at least 30% of the sole 108 has a thickness within + / - 10% of the maximum sole thickness Ts, more preferably at least 40% of the sole 108 has a thickness within + / - 10% of the maximum sole thickness Ts, and most preferably at least 50% of the sole 108 has a thickness within + / - 10% of the maximum sole thickness Ts.

[0052] It should be noted that maximum sole thickness Ts does not capture the full effect of mass concentrated in and / or near the sole 108 because, by definition, it does not take into account the weight pockets 130, the weight members, or additional elements required to secure the weight members within the weight pockets 130.

[0053] To better illustrate these features, Figures 5A and 5B are provided, where Figure 5A shows the sole 108 separated from the remainder of the golf club head 100, and Figure 5B shows the sole 208 according to an alternative embodiment of the present invention.

[0054] 5A, the sole 108 is shown separated from the remainder of the golf club head 100. From this perspective, it is much easier to see that the weight pockets 130, weight members (not shown), and surrounding structures may concentrate mass in and / or near the sole 108 to move the CG 110 closer to the ground. It is also seen that describing a portion of the sole 108 as having a substantially constant thickness does not fully capture how the sole 108 contributes to moving the CG 110 closer to the ground. In particular, describing the sole 108 in this manner does not capture the influence of the weight members (not shown) or portions of the sole 108 that define and / or support the weight pockets 130.

[0055] It should be noted here that identifying the portion that defines the sole 108 of the golf club head 100 is not as simple as identifying the bottom of the golf club head 100. For example, the sole 108 may be defined as the entirety of the golf club head 100 as seen from directly underneath the golf club head 100 when the golf club head 100 is in a normal address position. Alternatively, the sole 108 may be defined as the portion of the golf club head 100 that is bounded by the lower portion of the skirt 112 and the lower portion of the striking face 120.

[0056] To quantify the impact of the sole 108 in a meaningful and simplified manner in accordance with an exemplary embodiment of the present invention, the sole 108 may be defined as a portion of the golf club head 100 that is located approximately at the bottom center of the golf club head 100 and has an exterior surface area of ​​between about 25 cm2 and about 35 cm2. The sole 108, including the weight pocket 130 and the weight member (not shown) therein, may have a total mass of between about 50 g and about 80 g.

[0057] FIG. 5B illustrates a sole 208 that includes a weight pocket 130 that accommodates a weight member (not shown) having the same perimeter shape, surface area, and total mass as the sole 108 and the same density as the golf club head 100 .

[0058] The sole 208 is configured to be compatible with the sole 108, in that the sole 208 has the same circumferential shape, the same outer surface area of ​​about 25 cm2 to about 35 cm2, and the same mass of about 50 g to about 80 g. However, in contrast to the sole 108, the sole 208 does not include a weight pocket, and therefore the sole 208 has an increased thickness compared to the sole 108. The increased thickness of the sole 208 allows the overall effect of the sole 208 on the position of the CG 110 to be quantified.

[0059] According to an embodiment of the present invention, the sole 208 may have an average effective sole thickness Tsa of about 2.4 mm to about 3.2 mm, preferably about 2.5 mm to about 3.1 mm, and most preferably about 2.6 mm to about 3.0 mm. The average effective sole thickness Tsa is determined by dividing the total mass of the sole 208 by the external surface area of ​​the sole 208. Thus, although the average effective sole thickness Tsa is a constant thickness within the sole 208, the average effective sole thickness Tsa takes into account the mass contributed by the weight pocket 130 and the weight member (not shown) contained therein. Thus, since the sole 108 and the sole 208 have the same total mass and external surface area, it can be said that the sole 108 has the same average effective sole thickness Tsa as the sole 208. Furthermore, the sole 208 is configured to have the same effect on the position of the CG 110 and the MOI of the golf club head 100 as the sole 108.

[0060] The combined effects on the CG-Yg116 measurement associated with the reduction in minimum thickness of the crown 106, the reduction in maximum thickness of the striking face 120, the modified construction of the hosel 124 which opens to the interior of the golf club head 100, and the distribution of the above-mentioned saved mass in and / or near the sole 108, 208 as described above, result in a CG-Yg116 measurement that is about 1.5 mm to about 2.0 mm lower than known steel golf club heads having the conventional dimensions described above.

[0061] It should be noted here that the low CG-Yg116 measurements alone do not accurately describe and explain this invention, since golf club heads that are low in volume or excessively shallow (short peak crown height and / or short face height) may inherently have low CG-Yg measurements. It is therefore important to recognize that this invention is based on the interrelationships between the various values ​​achieved by the CG-Yg116 measurements and the associated CG-C, MOI, volume, and height measurements described above.

[0062] Another way to understand the impact of the mass savings discussed above is to look at the percentage of the mass of the golf club head 100 that is concentrated in the lower portion of the golf club head 100. Returning to Figure 3, it is useful to think of the distribution of mass within the golf club head 100 as a percentage of the peak crown height 117 measurement.

[0063] The mass of the portion of the golf club head 100 below the XZ plane whose vertical height from the ground G is equal to 25% of the measured peak crown height 117 is greater than about 45% of the total mass of the golf club head 100, greater than about 48% of the total mass of the golf club head 100, and most preferably greater than about 50% of the total mass of the golf club head 100.

[0064] The mass of the portion of the golf club head 100 below the XZ plane whose vertical height from the ground G is equal to 20% of the measured peak crown height 117 is greater than about 38% of the total mass of the golf club head 100, greater than about 41% of the total mass of the golf club head 100, and most preferably greater than about 43% of the total mass of the golf club head 100.

[0065] The mass of the portion of the golf club head 100 below the XZ plane whose vertical height from the ground G is equal to 15% of the measured peak crown height 117 is greater than about 27% of the total mass of the golf club head 100, greater than about 30% of the total mass of the golf club head 100, and most preferably greater than about 32% of the total mass of the golf club head 100.

[0066] The mass of the portion of the golf club head 100 below the XZ plane whose vertical height from the ground G is equal to 10% of the measured peak crown height 117 is greater than about 12% of the total mass of the golf club head 100, greater than about 15% of the total mass of the golf club head 100, and most preferably greater than about 17% of the total mass of the golf club head 100.

[0067] By concentrating most of the mass of the golf club head 100 in the sole 108 of the golf club head 100, the CG-Yg 116 can be reduced as discussed above.

[0068] It is now important to discuss the relationship between the mass of the sole 108, 208 and the external surface area of ​​the sole 108, 208 specific to the present invention to better understand how the golf club head 100 achieves the inertial and dimensional characteristics described above. The ratio of sole mass to sole surface area helps to quantify the present golf club head 100 as shown in the following equation. In one exemplary embodiment of the present invention, the sole mass to sole surface area ratio of the sole 108 and sole 208 is about 2.0 g / cm2 or greater, more preferably about 2.1 g / cm2 or greater, and most preferably about 2.2 g / cm2 or greater. Sole mass to sole surface area ratio = total mass of sole (g) / external surface area of ​​sole (cm 2 )

[0069] Another relationship specific to the present invention is the relationship between the measured peak crown height 117 and the measured CG-Yg 116. A ratio called the weighted peak crown height to CG-Yg ratio helps quantify the present golf club head 100 as shown in the following equation: The weighted peak crown height to CG-Yg ratio is the product of the cosine of the loft angle θ and the ratio of the measured peak crown height 117 to the measured CG-Yg 116. In one exemplary embodiment, the weighted peak crown height to CG-Yg ratio of the golf club head 100 is about 2.4 or greater, preferably about 2.5 or greater, and most preferably about 2.6 or greater. Weighted peak crown height to CG-Yg ratio = cos(θ)*peak crown height(mm) / CG-Yg(mm)

[0070] As discussed above, the weighted peak crown height to CG-Yg ratio is critical to this invention because it combines the performance benefits of a low CG 110 with the conventional shape of the golf club head 100. Although it is possible to lower the CG 110 using known techniques, these known techniques require the use of special materials and / or modification of the conventional shape of the golf club head, for example, by reducing the peak crown height or the radius from the ground to the top face of the golf club head.

[0071] Another relationship specific to the present invention relates to the difference between the peak crown height 117 measurement and CG-Yg 116. The perpendicular distance between the peak crown height 117 measurement and CG-Yg 116 is referred to as ΔYccg 119 and helps to quantify the present golf club head 100 as shown in the following equation: In one exemplary embodiment, ΔYccg 119 for the golf club head 100 is between about 22.0 mm and about 28.0 mm, preferably between about 23.0 mm and about 26.0 mm, and most preferably between about 24.0 mm and about 25.0 mm. ΔYccg = Peak crown height (mm) - CG - Yg (mm)

[0072] As discussed above, ΔYccg is critical to the present invention because it combines the performance benefits of low CG 110 with the conventional shape of the golf club head 100. Although it is possible to lower CG 110 using known techniques, these known techniques require the use of special materials and / or modification of the conventional shape of the golf club head, such as reducing the peak crown height or ground-to-top face radius of the golf club head.

[0073] Another relationship specific to the present invention is the relationship between the minimum crown thickness Tc and the maximum sole thickness Ts. The minimum crown thickness Tc as defined in the present invention refers to the thinnest walled portion of the crown 106, including any notches that may be present in the crown 106 portion of the golf club head. On the other hand, the maximum sole thickness Ts as defined in the present invention refers to the thickest walled portion of the sole 108, including sole graphics, but not including any sole portions associated with ribs or external weighting features that may create the visual illusion of a thicker sole 108. The maximum sole thickness to minimum crown thickness ratio is useful for quantifying the current golf club head 100, as shown in the following formula: In one exemplary embodiment of the present invention, the maximum sole thickness to minimum crown thickness ratio is about 4.0 or greater, preferably about 4.5 or greater, and most preferably about 4.75 or greater. Maximum sole thickness to minimum crown thickness ratio = Maximum sole thickness (mm) / Minimum crown thickness (mm)

[0074] As discussed above, the ratio of maximum sole thickness to minimum crown thickness is critical to the present invention because it combines the performance benefits of a low CG 110 with the all-steel construction of the golf club head 100. While it is possible to similarly lower the CG 110 using known techniques, these known techniques require the use of specialized materials, such as forming the crown from a different material, such as titanium or a composite material.

[0075] Another relationship specific to the present invention is the relationship between the average effective sole thickness Tsa and the minimum crown thickness Tc. The average effective sole thickness to minimum crown thickness ratio helps to quantify the present golf club head 100, as shown in the following formula: In one exemplary embodiment, the average effective sole thickness to minimum crown thickness ratio is from about 3.5 to about 9.0, preferably from about 4.5 to about 8.5, and most preferably from about 5.0 to about 8.0. Average Effective Sole Thickness to Minimum Crown Thickness Ratio = Average effective sole thickness (mm) / minimum crown thickness (mm)

[0076] As discussed above, the average effective sole thickness to minimum crown thickness ratio is critical to the present invention because it combines the performance benefits of a low CG 110 with the all-steel construction of the golf club head 100. While it is possible to get the CG 110 similarly close to the ground using known techniques, these known techniques require the use of specialized materials, such as forming the crown from a different material, such as titanium or a composite material.

[0077] Other than in the working examples, or unless expressly stated otherwise, all numerical ranges, amounts, values, and percentages in the above specification section, such as amounts of materials, moments of inertia, center of gravity locations, lofts, draft angles, various performance ratios, etc., can be read as if preceded by the word "about" even if the value, amount, or range does not expressly appear in the word "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the above specification and appended claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0078] According to another embodiment of the present invention, the crown 106 may be formed of a lightweight material having a lower density than steel. For example, the crown 106 may be formed of a composite material or a titanium alloy. The golf club head 100 of the present invention having the crown 106 formed of a composite material as described above may exhibit a CG-Yg116 measurement that is at least 0.20 mm lower than a conventional golf club head having an all-steel construction. As described above, although a 0.20 mm reduction in the CG-Yg116 measurement may seem small at first glance, the present invention relies on several inventive features to achieve a lower CG-Yg116 measurement than other known golf club heads having the conventional dimensions described above.

[0079] 6 of the accompanying drawings shows an exploded view of a golf club head 600 in accordance with an alternative embodiment of the present invention, in which the striking face 620 is an L-cup shaped striking face with a sole return 623 rather than a face insert as shown in the previous embodiment. By providing an L-cup shaped striking face, not only can the performance of the golf club head 600 be further improved by improving the location of the center of gravity of the golf club head 600 within the ranges previously described, but it can also provide additional structural integrity to the leading edge of the golf club head 600 itself. By increasing the structural integrity of the golf club head 600 at the leading edge, the performance of the golf club head 600 can be further improved by reducing the spin of shots that strike the striking face 620, which is a common phenomenon in fairway woods such as the present invention.

[0080] The striking face 620 may be attached to the body portion 640 of the golf club head 600 through a front opening 621 (shown in FIG. 7) by conventional attachment techniques such as welding, although in alternative embodiments of the present invention, other attachment techniques such as brazing, adhesives, or other types of attachment techniques may be used without departing from the scope and content of the present invention.

[0081] 6 differs from previous embodiments of the invention in that it includes a crown opening 644 that is surrounded by a recessed protrusion 642 for receiving the crown 606. In this current embodiment of the invention, the crown 606 is made from a lightweight composite material that reduces the weight of that portion of the golf club head 600. Using a lightweight composite material to form the crown 606 creates more discretionary mass that can be more strategically placed to achieve the CG, MOI, and mass distribution values ​​discussed above.

[0082] 7 of the accompanying drawings shows another exploded perspective view of the golf club head 600 from another angle, where the front opening 621 is more clearly shown. As can be seen from this view, the front opening 621 includes the tip of the golf club head 600 and at least partially forms the front of the sole of the golf club head 600. As a result, due to the shape of the front opening 621, the striking face 620 having an L-cup shape forms the tip of the golf club head 600 together with the front of the sole of the golf club head 600. However, it should be noted that other types of complementary shapes between the front opening 621 and the striking face 620, different from the L-cup shape shown here, may also be used without departing from the scope and content of the present invention, so long as the shape of the striking face 620 complements the shape of the front opening 621.

[0083] 8 of the accompanying drawings shows a cross-sectional view of the golf club head 600 taken along a vertical plane passing through the face center 622 and extending along the Z-axis. This cross-sectional view of the golf club head 600 allows the various thicknesses and dimensions of the golf club head 600 to be more fully illustrated. First, it can be seen that the striking face 620 can have a variable thickness, with the thickest portion of the striking face having a first thickness Tf1 and located near the geometric face center 622, while the peripheral portion of the striking face can have a thinner thickness Tf2. Unlike previous embodiments in which the striking face has a single thickness, the present invention utilizes a variable face thickness profile to reduce the first thickness Tf1 to between about 1.8 mm and about 2.1 mm, more preferably between about 1.9 mm and about 2.1 mm, and most preferably between about 2.0 mm and about 2.1 mm. The second thickness Tf2, which is always smaller than the first thickness Tf1, may generally comprise a thickness between about 1.70 mm and about 1.75 mm, more preferably between about 1.70 mm and about 1.73 mm, and most preferably between about 1.70 mm and about 1.72 mm.

[0084] The cross-sectional view of the golf club head 600 shown in FIG. 8 not only illustrates the striking face 620, but also illustrates the new and important features of the L-cup striking face 620 along with its various dimensions. First, FIG. 8 illustrates that the striking face 620 includes a sole return distance 623DR that forms the leading edge and front of the sole of the golf club head 600. The sole return 623 distance DR is measured from the front-most portion of the leading edge toward the rear of the L-cup striking face 620 and is generally between about 9.0 mm and about 11.0 mm, more preferably between about 9.5 mm and about 10.5 mm, and most preferably between about 10.0 mm in this embodiment of the invention. In addition to the length of the sole return 623 distance DR, the thickness TR of the sole return 623 is also shown in the accompanying FIG. 8. The TR shown in this embodiment of the invention is generally between about 0.8 mm and about 1.0 mm, more preferably between about 0.85 mm and about 0.95 mm, and most preferably between about 0.9 mm.

[0085] Having established the dimensions of the striking face 640, it is instructive to note that the dimensions of this L-cup shaped striking face 620 are very important to the proper performance of the golf club head 600 of the present invention, in particular the relationship between the substantially vertical planar portion of the L-cup striking face 620 and the lower return portion of the L-cup striking face 620. Thus, in accordance with the present invention, the golf club head 600 has a maximum face thickness to sole return thickness ratio of about 1.70 to about 2.18, more preferably about 1.78 to about 2.03, and most preferably about 1.88 to about 1.91, where the maximum face thickness to sole return thickness ratio is defined as follows: Maximum face thickness to sole return thickness ratio = Maximum face thickness T f1 / Sole return thickness (T R )

[0086] Another important ratio that can be deduced from the dimensions of the golf club head 600 shown in FIG. 8 is the maximum face thickness to sole return distance ratio, defined as follows: Maximum face thickness to sole return distance ratio = Maximum face thickness (T f1 ) / Sole Return Distance (D R ) The maximum face thickness to sole return distance ratio according to the present invention is generally from about 0.15 to about 0.19, more preferably from about 0.16 to about 0.18, and most preferably about 0.17.

[0087] Finally, it should be noted that the sole return 623 portion of the striking face 622 has an inherent relationship between sole return 623 distance and sole return 623 thickness, producing a sole return distance to thickness ratio defined as follows: Sole return distance to thickness ratio = Sole Return Distance (D R ) / Sole return thickness (T R ) The sole return distance to thickness ratio according to the present invention is generally from about 9 to about 13.75, more preferably from about 10 to about 12.35, and most preferably about 11.

[0088] 8 of the accompanying drawings, in addition to showing the dimensions and characteristics of the striking face 620, also shows some auxiliary features of the golf club head 600. Near the top of the golf club head 600, it can be seen that the crown 606 made of high strength composite material has a thickness TC of less than about 0.60 mm, more preferably less than about 0.55 mm, and most preferably less than about 0.54 mm. The golf club head 600 has a ground to top face radius measurement 618 of between about 33.0 mm and about 36 mm, more preferably between about 34.0 mm and about 35 mm, and most preferably between about 34.5 mm. Finally, the golf club head 600 has a peak crown height 617 of between about 36 mm and about 40 mm, more preferably between about 37 mm and about 39 mm, and most preferably between about 38 mm.

[0089] 9, 10 and 11 of the accompanying drawings show two exploded perspective views and one cross-sectional view of a golf club head 900 according to an alternative embodiment of the present invention, in which a striking face 920 has a crown return 925 in addition to a sole return 923 and is C-cup shaped. Generally speaking with respect to FIGS. 9, 10 and 11, it can be seen that the golf club head 900 has a body portion 940 with a front opening 921 shaped without a leading edge and crown transition to accommodate a similarly shaped striking face 920 with a crown return 925 and a sole return 923. The body portion 940 also includes a crown opening 944 with a recessed shelf 942 adapted to receive a lightweight crown 906, typically made of a lightweight composite material, as in the previous embodiments. The means by which striking face 920 and crown 906 are attached to front opening 921 and crown opening 944, respectively, are similar to the methods of attaching striking face 620 and crown 606 described above.

[0090] The cross-section of golf club head 900 shown in Figure 11 is similar to the cross-section of golf club head 600 shown in Figure 8 and allows a clearer view of the interior of golf club head 900. This cross-section of golf club head 900 shows that the striking face 920 is in the shape of a C-cup, with a crown return and a sole return as previously described, illustrating how this alternative embodiment can achieve the above-mentioned CG and MOI characteristics, as well as the interfaces between the various components.

[0091] FIG. 12 of the accompanying drawings shows a heel side exploded view of a golf club head 1200 in accordance with yet another embodiment of the present invention, where the striking face 1220 includes an improved variable thickness profile to utilize a sole return 1223 of the striking face 1220. As with the previous embodiment, the striking face 1220 with the sole return 1223 forms an L-shape, more commonly referred to as an L-cup face, without departing from the scope and content of the present invention. The striking face 1220 is attached to a body portion 1240 of the golf club head 1200, which may include a crown opening 1244 with a recessed shelf 1242 configured to receive the crown 1206. To better illustrate the improved variable face thickness profile of the striking face 1220, FIG. 13 is shown below.

[0092] FIG. 13 of the accompanying drawings shows an enlarged perspective view of a striking face 1220 according to this further alternative embodiment of the present invention. This enlarged rear view of the striking face 1220 helps to illustrate the variable face thickness profile associated with this embodiment, which is important for achieving the improved performance of the striking face 1220 of the present invention. First of all, it is worth noting that although the present variable face profile is illustrated in connection with an L-shaped striking face 1220 having a single return portion 1223 and works best with this L-shaped striking face 1220, the variable face profile illustrated herein may also work with other types of striking faces, such as C-cups, face inserts, or other types of striking face designs, without departing from the scope and content of the present invention. The variable thickness profile of the striking face 1220 may generally be defined by a substantially flat front surface and a non-flat rear surface, as shown in FIG.

[0093] The striking face 1220 shown in FIG. 13 may include a thickened central portion 1250 that is generally not located near the geometric center of the striking face 1220 of a conventional design. In fact, a closer inspection of the striking face 1220 shown in FIG. 13 reveals that in accordance with this exemplary embodiment of the present invention, the thickened central portion 1250 is located near the upper crown portion of the golf club head 1200 (shown in FIG. 12) to form a crown deflection location. In addition to being a crown deflection location, the thickened central portion 1250 exhibits a unique shape that resembles a flattened ellipse with a significantly higher aspect ratio than conventional variable face thickness designs. The resulting thickened central portion 1250 may include a thickened central portion heel end 1250-H and a thickened central portion toe end 1250-T that are more pointed in shape than the thickened central portions of variable face thickness profiles associated with conventional traditional golf club heads. Because of its unique shape, the thickened central portion is not of a constant thickness as in conventional variable face thickness designs, but rather the thickened central portion heel end 1250-H and the thickened central portion toe end 1250-T can be of a reduced thickness as compared to the central portion of the thickened central portion 1250.

[0094] Above the crown-biased thickened central portion 1250 is an upper transition portion 1252 that changes in thickness from the thickened central portion 1250 to a circumferential thickness. It can be seen in FIG. 13 that because the thickened central portion 1250 is highly crown-biased, the slope of the transition at this upper transition portion 1252 (also referred to as the upper transition slope) is very high, especially when compared to a conventional variable face thickness profile in which the thickened central portion is more centrally located. Conversely, as a result of the above, the lower transition portion 1254 may exhibit a lower transition slope that is significantly less than a conventional variable face thickness profile based on the location of the crown-biased thickened central portion 1250.

[0095] As a result, due to the extreme departures from conventional variable face thickness designs in both upper transition portion 1252 and lower transition portion 1254, the difference between the slopes of the two transition portions is higher than normal. In other words, the ratio of upper transition slope to lower transition slope in the present invention will generally be significantly higher than in conventionally designed striking faces.

[0096] FIG. 14 of the accompanying drawings shows a direct rear view of the striking face 1220, which may illustrate some of the dimensional characteristics of the striking face 1220. First, this direct rear view of the striking face 1220 illustrates the extreme elliptical shape of the thickened central portion 1250 described above. This extreme elliptical shape of the thickened central portion 1250 may generally have a width W greater than about 45 mm, more preferably greater than about 50 mm, and most preferably about 52 mm. The height H of the extreme elliptical shape of the thickened central portion 1250 may generally be less than about 7 mm, more preferably less than about 6 mm, and most preferably less than about 5 mm. The aspect ratio of the thickened central portion 1250, defined as the width W divided by the height H, may generally be greater than about 5, more preferably greater than about 8, and most preferably greater than about 10.

[0097] In addition to showing the aspect ratio of the thickened central portion 1250, accompanying FIG. 14 shows the various heights of the upper transition portion 1252 and the lower transition portion 1254 and from where those heights are measured. The height H2 of the upper transition portion 1252 is generally between about 2.5 mm and about 3.5 mm, more preferably between about 2.75 mm and about 3.25 mm, and most preferably about 3.0 mm. This height H2 can be combined with the thickness of the end area described below in the cross-sectional view of the striking face 1220 shown in FIG. 15 to calculate the upper transition slope described above. Similarly, the height H4 of the lower transition portion 1254 is generally between about 18 mm and about 19 mm, more preferably between about 18.25 mm and about 18.75 mm, and most preferably about 18.50 mm. This height H4 can also be combined with the thickness of the end area of ​​the lower transition portion 1254 shown below in FIG. 15 to calculate the lower transition slope described above.

[0098] Finally, Figure 14 of the accompanying drawings shows section line A-A' drawn through the geometric face center of the golf club head 1200 (shown in Figure 12) to provide a cross-sectional view of the striking face 1220 of Figure 15. Note that section line A-A' shown in Figure 14 passes through the geometric face center 1222 of the club head 1200 (shown in Figure 12), not through the striking face 1220 insert itself.

[0099] FIG. 15 of the accompanying drawings shows a cross-sectional view of a striking face 1220 in accordance with a further alternative embodiment of the present invention taken along section line A-A' shown in FIG. 14. This cross-sectional view of the striking face 1220 more clearly illustrates the variable thickness profile with the various thicknesses and heights now identified. First, it can be seen that the striking face 1220 has an L-cup shape with a portion of the sole return 1223. It can therefore be said that the striking face 1220 can be further divided into an upper transition portion 1252, a thickened central portion 1250, a lower transition portion 1254, and a sole return 1223 without departing from the scope and content of the present invention.

[0100] Beginning near the crown 106 (as shown in FIG. 1), the upper transition portion 1252 may have an upper thickness T1 of between about 1.65 mm and about 1.85 mm, and most preferably between about 1.70 mm and about 1.80 mm, and most preferably about 1.75 mm. Within this upper transition portion 1252, the thickness of the striking face 1220 begins to increase very rapidly to a lower thickness T2 of between about 2.10 mm and about 2.30 mm, and more preferably between about 2.15 mm and about 2.25 mm, and most preferably about 2.20 mm. This approximately 0.45 mm thickness transition occurs at the aforementioned height H2 between about 2.5 mm and about 3.5 mm, and more preferably between about 2.75 mm and about 3.25 mm, and most preferably about 3.0 mm, resulting in a slope of the transition of about 8 degrees or more, more preferably about 9 degrees or more, and most preferably about 10 degrees or more. In other words, it may be said that the upper transition portion 1252 has an actual slope, as defined by the ascending slope of the upper transition portion 1252, of about 0.10 or greater, more preferably about 0.125 or greater, and most preferably about 0.15 or greater.

[0101] Based on the angles and slopes defined above, the ratio of the upper transition slope to the lower transition slope may be greater than about 1.14, more preferably greater than about 1.5, and most preferably greater than about 2.0, which is important to the balance of performance and durability of the striking face 1220 of the present invention.

[0102] Immediately below the upper transition portion is the thickened central portion 1250, which may have a generally constant vertical thickness such that thicknesses T2 and T3 may be equal, between about 2.10 mm and about 2.30 mm, more preferably between about 2.15 mm and about 2.25 mm, and most preferably about 2.20 mm. It is noted here that, as shown in FIG. 15, although the thickened central portion 1250 has a constant vertical thickness, its thickness tapers horizontally to the aforementioned thickness T1 at the thickened central portion heel end 1250-H and the thickened central portion toe end 1250-T, resulting in a variable thickness in that region in a different view than that shown in FIG.

[0103] Directly below the thickened central portion 1250 is a lower transition portion which decreases from a thickness T3 to a thickness T4. Although the thickness of T3 has already been described as being the same as the thickness T2, the thickness T4 according to the present invention is generally between about 1.45 mm and about 1.65 mm, more preferably between about 1.50 mm and about 1.60 mm, and most preferably between about 1.55 mm. This decrease in thickness of about 0.65 mm in the lower transition portion occurs more gradually over a height H4 of between about 18 mm and about 19 mm, more preferably between about 18.25 mm and about 18.75 mm, and most preferably over the aforementioned about 18.50 mm. This essentially same decrease in thickness in the lower transition portion 1254 occurs over a significantly longer span than the lower transition portion 1252, resulting in a slope of the lower transition of less than about 7 degrees, more preferably less than about 6 degrees, and most preferably less than about 5 degrees. In other words, lower transition portion 1254 has an actual slope, as defined by the rise / run of upper transition portion 1252, of less than about 0.05, more preferably less than about 0.04, and most preferably less than about 0.035.

[0104] FIG. 15 of the accompanying drawings, in addition to showing the various thicknesses of the front planar portion of the striking face 1220, also shows three different thicknesses of the sole return 1223, illustrating its unique thickness profile. The sole return 1223 has an initial front thickness T5 of approximately 0.85 mm exactly 2.9 mm rearward from the forward most point 1225 of the striking face. The sole return 1223 decreases to an intermediate thickness T6 of approximately 0.72 mm exactly 6.2 mm rearward from the forward most point 1225. Finally, the sole return 1223 reverses the thickness trend by increasing in thickness to a final thickness T7 of approximately 0.90 mm exactly 9.2 mm rearward from the forward most point. This unique thickness profile, going from thin to thick and back again, is critical to the performance of the L-cup striking face 1220, allowing for increased ball speeds on low hits on the striking face 1220. In other words, the initial front thickness T5 of the sole return 1233 is greater than the intermediate thickness T6, and the terminal thickness T7 is generally greater than the initial front thickness T5. Since the initial front thickness T5 is already greater than the intermediate thickness T6, the terminal thickness T7 can also be greater than the intermediate thickness T6.

[0105] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of this invention are approximations, the numerical values ​​set forth in the specification examples are reported as precisely as possible, however, any numerical values ​​inherently contain errors resulting from the standard deviation found in each experimental measurement. Moreover, when numerical ranges are given for various things, it is to be understood that combinations of the values ​​recited can be used.

[0106] It should be noted that the foregoing relates to exemplary embodiments of the present invention and that modifications may, of course, be made without departing from the scope and spirit of the invention as set forth in the following claims.

Claims

1. In the golf club head, a striking face having a face center, a crown, a sole opposite the crown, a heel, a toe opposite the heel, and a hosel adjacent the heel and configured to join the golf club head to a shaft; the striking face further having a variable face thickness profile having a substantially planar front surface and a non-planar rear surface; The X-axis is defined as a horizontal axis tangent to the face center of the striking face in a positive direction toward the heel of the golf club head, the Y-axis is a vertical axis perpendicular to the X-axis in a positive direction toward the crown of the golf club head, and the Z-axis is perpendicular to both the X-axis and the Y-axis in a positive direction toward the front of the golf club head, with the origin of the X-axis, Y-axis, and Z-axis being centered at the center of gravity (CG) of the golf club head; The variable face thickness profile of the striking face further comprises: Crown bias thick central part, an upper transition portion having an upper transition slope; and a lower transition portion having a lower transition slope; The golf club head, wherein the upper transition slope is greater than the lower transition slope.

2. 2. The golf club head of claim 1, wherein the upper transition slope is greater than about 8 degrees and the lower transition slope is less than about 7 degrees.

3. 3. The golf club head of claim 2, wherein the upper transition slope is greater than about 9 degrees and the lower transition slope is less than about 6 degrees.

4. 4. The golf club head of claim 3, wherein the upper transition slope is greater than about 10 degrees and the lower transition slope is less than about 5 degrees.

5. 2. The golf club head of claim 1, wherein a ratio of the upper transition slope to the lower transition slope is greater than about 1.

14.

6. 6. The golf club head of claim 5, wherein a ratio of the upper transition slope to the lower transition slope is greater than about 1.

5.

7. 7. The golf club head of claim 6, wherein the ratio of the upper transition slope to the lower transition slope is greater than about 2.

0.

8. 2. The golf club head of claim 1, wherein the crown bias thickened central portion is elliptical, the elliptical shape having an aspect ratio greater than about 5.

9. The golf club head of claim 8 , wherein the aspect ratio is greater than about eight.

10. The golf club head of claim 9 , wherein the aspect ratio is greater than about ten.

11. 2. The golf club head of claim 1, wherein the crown bias thickened central portion has a width greater than about 45 mm.

12. 12. The golf club head of claim 11, wherein the crown bias thickened central portion has a width greater than about 50 mm.

13. 13. The golf club head of claim 12, wherein the crown bias thickened central portion has a width greater than about 52 mm.

14. In the golf club head, a striking face having a face center, a crown, a sole opposite the crown, a heel, a toe opposite the heel, and a hosel adjacent the heel and configured to join the golf club head to a shaft; a sole return located at a bottom of the striking face; the striking face further having a variable face thickness profile having a substantially planar front surface and a non-planar rear surface; The X-axis is defined as a horizontal axis tangent to the face center of the striking face in a positive direction toward the heel of the golf club head, the Y-axis is a vertical axis perpendicular to the X-axis in a positive direction toward the crown of the golf club head, and the Z-axis is perpendicular to both the X-axis and the Y-axis in a positive direction toward the front of the golf club head, with the origin of the X-axis, Y-axis, and Z-axis being centered at the center of gravity (CG) of the golf club head; the sole return having an initial front thickness greater than an intermediate thickness; The sole return has an end thickness greater than the intermediate thickness.

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