Club head with balanced impact and swing performance characteristics

Abstract

There is a need for a club head having improved impact performance characteristics balanced against improved swing characteristics.SOLUTION: The present specification describes embodiments of the golf club head 100 that balance the following parameters: a low and rearward club head center of gravity location 170, a high moment of inertia, a large Ixy product of inertia, and low aerodynamic drag. Also described herein are methods of manufacturing embodiments of golf club heads having balanced club head center of gravity locations, moments of inertia, products of inertia, and aerodynamic drag.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit of U.S. Provisional Patent Application No. 62 / 848,429, filed May 15, 2019, and U.S. Provisional Patent Application No. 62 / 878,692, filed July 25, 2019, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a golf club head, and more particularly to a golf club head having balanced impact and swing performance characteristics. [Background technology]

[0003] Various golf club head design parameters, such as volume, center of gravity location, and product of inertia, affect impact performance characteristics (e.g., spin, launch angle, velocity, forgiveness) and swing performance characteristics (e.g., aerodynamic drag, ability to square the club head at impact). Often, club head designs that improve impact performance characteristics can adversely affect swing performance characteristics (e.g., aerodynamic drag), or alternatively, club head designs that improve swing performance characteristics can adversely affect impact performance characteristics. Therefore, there is a need in the art for club heads with improved impact performance characteristics balanced against improved swing characteristics. [Brief explanation of the drawings]

[0004] [Figure 1] FIG. 2 is a front view of the golf club head.

[0005] [Figure 2] 2 is a side cross-sectional view of the golf club head of FIG. 1 taken along cross-sectional line 2-2.

[0006] [Figure 3]FIG. 2 is a bottom view of the golf club head of FIG. 1.

[0007] [Figure 4] FIG. 2 is a side cross-sectional view of the golf club head of FIG. 1.

[0008] [Figure 5] FIG. 2 is an enlarged side cross-sectional view of the golf club head of FIG. 1.

[0009] [Figure 6] FIG. 2 is an enlarged side cross-sectional view of the golf club head of FIG. 1.

[0010] [Figure 7] FIG. 2 is a plan view of the golf club head of FIG. 1.

[0011] [Figure 8A] FIG. 2 is a toe-side view of the golf club head of FIG. 1.

[0012] [Figure 8B] FIG. 2 is a top view of the golf club head of FIG. 1.

[0013] [Figure 8C] FIG. 2 is a front view of the golf club head of FIG. 1.

[0014] [Figure 9] 2 is a top view of the golf club head rotation after impact in FIG. 1.

[0015] [Figure 10] 2 is an illustration of the effect of the product of inertia Ixy on the delofting force from a below-center hit of the golf ball using the golf club head of FIG. 1;

[0016] [Figure 11] 2 is an illustration of the effect of the product of inertia Ixy on the lofting force from an above-center hit of the golf ball using the golf club head of FIG. 1;

[0017] [Figure 12] 2 is an illustration of the effect of the product of inertia Ixz on the delofting force from a below-center hit of a golf ball using the golf club head of FIG. 1;

[0018] [Figure 13] 2 is an illustration of the effect of the product of inertia Ixz on the lofting force from an above-center hit of the golf ball using the golf club head of FIG. 1.

[0019] [Figure 14A] 1 illustrates the relationship between side spin imparted to a golf ball and impact locations above or below the geometric center of a typical prior art golf club head.

[0020] [Figure 14B] 2 illustrates the relationship between side spin imparted to a golf ball and an impact location above or below the geometric center of the golf club head of FIG. 1.

[0021] [Figure 15] 1 illustrates the relationship between the Ixy ratio and the center of gravity height for various known golf club heads.

[0022] [Figure 16] 1 illustrates the relationship between the Ixy ratio and drag force for various known golf club heads.

[0023] [Figure 17] 1 illustrates the relationship between Ixz ratio and center of gravity height for various known golf club heads.

[0024] [Figure 18] 1 illustrates the relationship between Ixz ratio and drag force for various known golf club heads.

[0025] [Figure 19] 1 illustrates a bottom view of an exemplary golf club head.

[0026] [Figure 20] 20 shows a top view of the golf club head of FIG. 19.

[0027] [Figure 21] 20 shows a heel side cross-sectional view taken along the side cross-sectional line II in FIG. 19.

[0028] [Figure 22] 20 shows a tow side cross-sectional view taken along the side cross-sectional line II in FIG. 19.

[0029] [Figure 23] 19 illustrates the actual relationship between side spin imparted to a golf ball and impact locations above or below the geometric center of the golf club head of FIG. 19.

[0030] Other aspects of the present disclosure will become apparent by consideration of the detailed description and accompanying drawings.

[0031] For simplicity and clarity of explanation, the drawings show general construction methods, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the present disclosure. Moreover, elements in the drawings are not necessarily drawn to scale. For example, the dimensions of some of the elements in the drawings may be exaggerated relative to other elements to help improve understanding of embodiments of the present disclosure. The same reference numbers in different drawings refer to the same elements. DETAILED DESCRIPTION OF THE INVENTION

[0032] The golf club heads described below utilize several relationships that increase and maximize club head product moments of inertia while maintaining a low, rearward CG position and reduced aerodynamic drag. Specifically, the golf clubs described herein have a low, rearward CG as specified. The golf clubs also have a high crown-sole moment of inertia (Ixx) and a high heel-toe moment of inertia (Iyy). The golf clubs also have a large (and positive) Ixy product of inertia term that is paired with a small (and negative) Ixz product of inertia term to effectively counteract the harmful side spin caused by hitting golf shots above and below center. The use of removable or recessed weights (or weighted panel zones) allows for discretionary weight removal and placement at specific locations on (and within) the club head to balance the club head's moments of inertia, products of inertia, center of gravity, and drag profile.

[0033] The golf club heads described herein also have low aerodynamic drag relative to golf club heads with similar CG locations and moments of inertia. Maximizing crown height while maintaining a low, aft CG location reduces aerodynamic drag. The transition profiles from striking face to crown, striking face to sole, and / or crown to sole along the back end of the golf club head provide a means to reduce aerodynamic drag. The use of turbulators and strategic placement of hosel weights further reduces aerodynamic drag.

[0034] The golf clubs described below use several relationships that balance the club head's moments of inertia and products of inertia relative to a lower, rearward CG position while maintaining or reducing aerodynamic drag. Balancing these relationships between CG, moments of inertia, products of inertia, and drag improves impact performance characteristics (e.g., prevention of side spin on high and low face hits, launch angle, ball speed, and forgiveness) and swing performance characteristics (e.g., aerodynamic drag, ability to square the club head at impact, swing speed). This balance is applicable to driver-type club heads.

[0035] The terms "first," "second," "third," "fourth," etc., in the specification and claims, if any, are used to distinguish between similar elements and are not necessarily intended to describe a particular sequential or chronological order. Terms so used should be understood to be interchangeable in appropriate circumstances, such that the embodiments described herein are capable of operating in orders other than those illustrated or otherwise described herein. Furthermore, the terms "comprise" and "have," and any conjugations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, device, or apparatus that includes a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such process, method, system, article, device, or apparatus.

[0036] If any, the terms "left," "right," "front," "rear," "top," "bottom," "above," "below," etc. in this specification and claims are used for descriptive purposes and not necessarily to describe permanent relative positions. It should be understood that terms so used are interchangeable in appropriate circumstances such that embodiments of the apparatus, methods, and / or articles of manufacture described herein are operable, for example, in orientations other than those illustrated or otherwise described herein.

[0037] Before any embodiments of the present disclosure are described in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure is applicable to other embodiments and can be practiced or carried out in various ways.

[0038] 1 and 2 show a golf club head 100 having a body 102 and a striking face 104. The body 102 of the club head 100 includes a front end 108, a back end 110 opposite the front end 108, a crown 116, a sole 118 opposite the crown 116, a heel 120, and a toe 122 opposite the heel 120. The body 102 also includes a skirt or rear edge 128 adjacent to and between the crown 116 and the sole 118, the skirt extending from near the heel 120 to near the toe 122 of the club head 100.

[0039] In many embodiments, the club head 100 is a hollow-body club head. In these embodiments, the body 102 and the striking face 104 may define an interior cavity of the golf club head 100. In some embodiments, the body 102 may extend around the crown 116, sole 118, heel 120, toe 122, back end 110, and front end 108 of the club head 100. In these embodiments, the body 102 defines an opening in the front end 108 of the club head 100, and the striking face 104 is disposed within the opening to form the club head 100. In other embodiments, the striking face 104 may extend across the entire front end 108 of the club head and may include a return portion that extends across at least one of the crown 116, sole 118, heel 120, and toe 122. In these embodiments, the return portion of the striking face 104 is coupled to the body 102 to form the club head 100.

[0040] The striking face 104 of the club head 100 comprises a first material. In many embodiments, the first material is a metal alloy, such as a titanium alloy, a steel alloy, an aluminum alloy, or any other metal or metal alloy. In other embodiments, the first material may include any other material, such as a composite material, a plastic, or any other suitable material or combination of materials.

[0041] The body 102 of the club head 100 includes a second material. In many embodiments, the second material is a metal alloy, such as a titanium alloy, a steel alloy, an aluminum alloy, or any other metal or metal alloy. In other embodiments, the second material can include any other material, such as a composite material, a plastic, or any other suitable material or combination of materials.

[0042] 1 , the club head 100 further includes a hosel structure 130 and a hosel axis 132 extending centrally through the bore of the hosel structure 130. In this example, the hosel coupling mechanism of the club head 100 includes the hosel structure 130 and a hosel sleeve 134. The hosel sleeve 134 may be coupled to the end of a golf shaft 136. The hosel sleeve 134 may be coupled to the hosel structure 130 in multiple configurations, thereby securing the golf shaft 136 to the hosel structure 130 at multiple angles relative to the hosel axis 132. However, there may be other instances in which the shaft 136 may be non-adjustably secured to the hosel structure 130.

[0043] The striking face 104 of the club head 100 defines a geometric center 140. In some embodiments, the geometric center 140 may be located at the geometric center point of the striking face perimeter 142 and the midpoint of the face height 144. In the same or other examples, the geometric center 140 may also be centered with respect to a designed impact zone 148, which may be defined by the area of ​​grooves 150 on the striking face. As an alternative approach, the geometric center of the striking face may be located based on a definition by a golf governing body, such as the United States Golf Association (USGA). For example, the geometric center of the striking face may be determined in accordance with Section 6.1 of the USGA Procedure for Measuring the Flexibility of a Golf Club Head (USGA-TPX3004, Rev. 1.0.0, May 1, 2008) (available at http: / / www.usga.org / equipment / testing / protocols / Procedure-For-Measuring-The-Flexibility-Of-A-Golf-Club-Head / ) ("Flexibility Procedure").

[0044] The geometric center 140 of the striking face 104 further defines a coordinate system with its origin at the geometric center 140 of the striking face 104. This coordinate system has an X' axis 1052, a Y' axis 1062, and a Z' axis 1072. The X' axis 1052 extends through the geometric center 140 of the striking face 104 in a direction from the heel 120 to the toe 122 of the club head 100. The Y' axis 1062 extends through the geometric center 140 of the striking face 104 in a direction from the crown 116 to the sole 118 of the club head 100 and is perpendicular to the X' axis 1052. The Z' axis 1072 extends through the geometric center 140 in a direction from the front end 108 toward the back end 110 of the club head 100 and is perpendicular to the X' axis 1052 and the Y' axis 1062.

[0045] The coordinate system defines an X'Y' plane extending through the X' axis 1052 and the Y' axis 1062, an X'Z' plane extending through the X' axis 1052 and the Z' axis 1072, and a Y'Z' plane extending through the Y' axis 1062 and the Z' axis 1072, where the X'Y', X'Z', and Y'Z' planes are all perpendicular to one another and intersect at the origin of the coordinate system located at the geometric center 140 of the striking face 104. The X'Y' plane extends parallel to the hosel axis 132 and is disposed at an angle corresponding to the loft angle of the club head 100 from the loft plane 1010. Furthermore, the X' axis 1052 is disposed at a 60-degree angle relative to the hosel axis 132 when viewed perpendicular to the X'Y' plane.

[0046] In these or other embodiments, the club head 100 may be viewed from a front view (FIG. 1) with the striking face 104 viewed perpendicular to the X'Y' plane. Additionally, in these or other embodiments, the club head 100 may be viewed from a side or cross-sectional side view (FIG. 2) with the heel 120 viewed perpendicular to the Y'Z' plane.

[0047] Club head 100 defines a depth 160, a length 162, and a height 164. As shown in FIG. 3 , the depth 160 of club head 100 can be measured as the farthest extent of club head 100 from front end 108 to back end 110 in a direction parallel to Z′ axis 1072.

[0048] The length 162 of the club head 100 may be measured as the farthest extent of the club head 100 from the heel 120 to the toe 122 in a direction parallel to the X′ axis 1052 when viewed from the front view ( FIG. 1 ). In many embodiments, the length 162 of the club head 100 may be measured based on definitions from a golf governing body, such as the United States Golf Association (USGA). For example, the length 162 of the club head 100 may be determined according to the USGA Procedure for Measuring the Club Head Size of Wood Clubs (USGA-TPX3003, Rev. 1.0.0, November 21, 2003) (available at https: / / www.usga.org / content / dam / usga / pdf / Equipment / TPX3003-procedure-for-measuring-the-club-head-size-of-wood-clubs.pdf) (“Procedure for Measuring the Club Head Size of Wood Clubs”).

[0049] The height 164 of the club head 100 may be measured as the farthest extent of the club head 100 from the crown 116 to the sole 118 in a direction parallel to the Y′ axis 1062 when viewed from the front view ( FIG. 1 ). In many embodiments, the height 164 of the club head 100 may be measured based on definitions from a golf governing body, such as the United States Golf Association (USGA). For example, the height 164 of the club head 100 may be determined according to the USGA Procedure for Measuring the Club Head Size of Wood Clubs (USGA-TPX3003, Rev. 1.0.0, November 21, 2003) (available at https: / / www.usga.org / content / dam / usga / pdf / Equipment / TPX3003-procedure-for-measuring-the-club-head-size-of-wood-clubs.pdf) (“Procedure for Measuring the Club Head Size of Wood Clubs”).

[0050] 1 and 2 , the club head 100 further includes a head center of gravity (CG) 170 and a head depth plane 1040 that extends through the geometric center 140 of the striking face 104 perpendicular to the loft plane 1010 in a direction from the heel 120 to the toe 122 of the club head 100. In some embodiments, the head CG 170 may be located at a head CG depth 172 from the loft plane 1010 measured in a direction perpendicular to the loft plane. The head CG 170 may also be located at a head CG height 174 from the head depth plane 1040 measured in a direction perpendicular to the head depth plane 1040. In many embodiments, the head CG 170 is located at a head CG depth 172 from the geometric center 140 of the striking face 104 measured in a direction parallel to the head depth plane 1040 from the loft plane 1010 toward the CG 170. In many embodiments, the head CG 170 is strategically positioned toward the sole 118 and back end 110 of the club head 100 based on various club head parameters such as volume and loft angle, as described below. In some embodiments, the head CG 170 is strategically positioned toward the sole 118 and back end 110 of the club head 100 based on various club head parameters such as volume and loft angle, as described below.

[0051] Head CG 170 defines the origin of a coordinate system having an x-axis 1050, a y-axis 1060, and a z-axis 1070. The y-axis 1060 extends through head CG 170 from crown 116 to sole 118 and is parallel to hosel axis 132 when viewed from the side and at a 30-degree angle from hosel axis 132 when viewed from the front. The x-axis 1050 extends through head CG 170 from heel 120 to toe 122 and is perpendicular to y-axis 1060 when viewed from the front and parallel to the X'Y' plane. The z-axis 1070 extends through head CG 170 from front end 108 to back end 110 and is perpendicular to x-axis 1050 and y-axis 1060. In many embodiments, the x-axis 1050 extends through the head CG 170 from the heel 120 to the toe 122 and is parallel to the X'-axis 1052, the y-axis 1060 extends through the head CG 170 from the crown 116 to the sole 118 and is parallel to the Y'-axis 1062, and the z-axis 1070 extends through the head CG 170 from the front end 108 to the back end 110 and is parallel to the Z'-axis 1072. I. Driver type club head

[0052] According to one example, golf club head 100 includes a high volume and a low loft. In many embodiments, golf club head 100 includes a driver-type club head. In other embodiments, golf club head 100 can include any type of golf club head having a loft and volume as described herein.

[0053] In many embodiments, the loft angle of the club head 100 is less than about 16 degrees, less than about 15 degrees, less than about 14 degrees, less than about 13 degrees, less than about 12 degrees, less than about 11 degrees, or less than about 10 degrees. Additionally, in many embodiments, the volume of the club head 100 is greater than about 400 cc, greater than about 425 cc, greater than about 450 cc, greater than about 475 cc, greater than about 500 cc, greater than about 525 cc, greater than about 550 cc, greater than about 575 cc, greater than about 600 cc, greater than about 625 cc, greater than about 650 cc, greater than about 675 cc, or greater than about 700 cc. In some embodiments, the club head volume can be between about 400cc and 600cc, between 445cc and 485cc, between 425cc and 500cc, between about 500cc and 600cc, between about 500cc and 650cc, between about 550cc and 600cc, between about 600cc and 650cc, between about 650cc and 700cc, between about 700cc and 750cc, or between about 750cc and 800cc.

[0054] In many embodiments, the length 162 of the club head 100 is greater than 4.85 inches. In other embodiments, the length 162 of the club head 100 is greater than 4.5 inches, greater than 4.6 inches, greater than 4.7 inches, greater than 4.8 inches, greater than 4.9 inches, or greater than 5.0 inches. For example, in some embodiments, the length 162 of the club head 100 may be between 4.6 and 5.0 inches, 4.7 and 5.0 inches, 4.8 and 5.0 inches, 4.85 and 5.0 inches, or 4.9 and 5.0 inches.

[0055] In many embodiments, the depth 160 of the club head 100 is at least 0.70 inches less than the length 162 of the club head 100. In many embodiments, the depth 160 of the club head 100 is greater than 4.75 inches. In other embodiments, the depth 160 of the club head 100 is greater than 4.5 inches, greater than 4.6 inches, greater than 4.7 inches, greater than 4.8 inches, greater than 4.9 inches, or greater than 5.0 inches. For example, in some embodiments, the depth 160 of the club head 100 may be between 4.6 and 5.0 inches, 4.7 and 5.0 inches, 4.75 and 5.0 inches, 4.8 and 5.0 inches, or 4.9 and 5.0 inches.

[0056] In many embodiments, the height 164 of the club head 100 is less than approximately 2.8 inches. In other embodiments, the height 164 of the club head 100 is less than 3.0 inches, less than 2.9 inches, less than 2.8 inches, less than 2.7 inches, or less than 2.6 inches. For example, in some embodiments, the height 164 of the club head 100 may be between 2.0 and 2.8 inches, 2.2 and 2.8 inches, 2.5 and 2.8 inches, or 2.5 and 3.0 inches. Furthermore, in many embodiments, the face height 144 of the club head 100 may be between approximately 1.3 inches (33 mm) and approximately 2.8 inches (71 mm). Still further, in many embodiments, the club head 100 may include a mass between 185 grams and 225 grams. II. Product of inertia

[0057] The golf club head 100 includes an inertia tensor. The inertia tensor for the golf club head 100 is represented by the following equation (1): The major axes of the inertia tensor (Ixx, Iyy, Izz) are maximized. The greater the moment of inertia of the golf club head 100, the less the club head 100 experiences rotation when torque is applied (i.e., the golf ball is not struck at the geometric center of the striking face). In many cases, it is assumed that if the MOI of the club head 100 is maximized and the golf ball is struck near the center 140, the golf ball will fly in a straight line. However, the golf club head still experiences three main rotational effects depending on the dynamics of an individual's golf swing.

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[0058] Referring to FIG. 8 , there are three primary rotational effects that the golf club head 100 experiences through impact and that are generated by the user (as the golfer swings the golf club). Referring to FIG. 8A , the first effect, lofting rate, is the time rate of change of the loft angle of the golf club head 100. The lofting rate is the rotational velocity of the golf club head 100 about the x-axis 1050. Referring to FIG. 8B , closure rate is the time rate of change of the face angle of the golf club head 100. The closure rate is the rotational velocity of the golf club head 100 about the y-axis 1060. Finally, referring to FIG. 8C , the third effect, drooping rate, is the time rate of change of the lie angle of the golf club head 100 at impact. The drooping rate is the rotational velocity of the golf club head 100 about the z-axis 1070.

[0059] In addition to the three main rotational effects generated by the user, the trajectory of the swing of the golf club 100 and the face angle of the golf club head 100 at impact are also part of the dynamics of an individual swing generated by the user. As previously mentioned, referring to FIG. 9, the golf club head of the golf club 100 rotates around the CG in all three coordinate axes throughout impact due to lofting, closure, and droop. The face angle of the golf club 100 at impact is the angle formed between the target line (the line formed from the golf ball to its desired endpoint) and the face line (a directional vector extending perpendicularly from the geometric center of the striking face when projected onto the ground). The golf club path is the angle formed between the target line and the velocity vector of the golf club head at the time of impact with the golf ball. The difference between the face angle and the club path generates unwanted side spin. The greater the difference between the face angle and the club path, the greater the side spin generated.

[0060] Additionally, when a golfer strikes the golf ball above or below the center of the golf club head, the club trajectory changes, which can generate side spin. For example, a golfer who strikes the ball in the center of the striking face, with a relatively small difference between face angle and club path (i.e., less than 1 degree), the golf ball typically flies on a target line to the golf ball's desired endpoint. However, when the same golfer strikes the ball off-center (heel-to-toe), such as by striking the ball just below or just above the center of the striking face (crown-to-sole), the difference can be 2 or 3 degrees, and / or unwanted side spin is generated at impact.

[0061] Referring again to FIG. 2, because the striking face of the golf club head is positioned at a loft angle, striking the golf ball above the center of the striking face results in an impact location closer to the CG in the Z direction. In stark contrast, when the golf ball is struck below the center of the striking face, the impact location is farther from the CG in the Z direction. The farther the impact location is from the CG (and thus, farther from the axis of rotation), the faster the shot will fly in the direction of the closure moment because the magnitude of the closure rate is positive relative to the CG at impact. For example, again assuming relatively straight ball launch parameters (approximately a one-degree difference between face angle and club path), golf shots struck above the center will tend to draw, while golf shots struck below the center will tend to fade.

[0062] When a golfer strikes the ball in the center of the club face (heel-to-toe direction), but strikes the ball just below or just above the center of the striking face (crown-to-sole direction), the club head experiences a lofting moment (τ x ), closure moment (τ y ), and the drooping moment (τ z ) the angular acceleration experienced by the club head when struck just above or just below center can be expressed by equations (2), (3), and (4) below. Assuming the golf ball is struck above or below the x-axis 1050 but is on (in contact with) the y-axis 1060 and z-axis 1070, the torque (τ y ≒0, τ z ≈0) is approximately zero. The torque (τ x ) is directly proportional to how far above or below center the golf ball is hit (i.e., the further above center the ball is hit, the greater the torque about the x-axis).

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[0063] To minimize the angular acceleration of the golf club head 100 at impact, the moments of inertia about the x-axis 1050, y-axis 1060, and z-axis 1070 can be increased, which then increases the tolerance of the golf club head 100 because the golf club head 100 better resists rotational torque about the major axes (x-axis, y-axis, z-axis). When the golf club head 100 better resists rotational torque about the major axes, the club head 100 has a higher tolerance for off-center impacts. However, even when the MOI is maximized and the golf ball is hit above or below center (with desirable launch parameters), the golf ball will still have undesirable side spin. In addition to the moment of inertia, the CG positioning and products of inertia can be optimized and / or balanced to improve the impact characteristics of the golf club head 100 and minimize unwanted side spin for high and low face hits, while maintaining forgiveness in the heel 120 to toe 122 direction.

[0064] In general, the product of inertia about two axes relates the symmetry of the club head 100 about a first axis to the symmetry of the club head 100 about a second axis. Thus, the closer the magnitude of the product of inertia about two axes is to zero, the less likely the golf club head 100 is to rotate simultaneously about its respective axis because the club head 100 is balanced symmetrically.

[0065] Equations (2), (3), and (4) show that as the moment of inertia increases, the magnitude of the angular acceleration experienced by the golf club head decreases when striking the golf ball above or below center. However, it is still possible to zero out the products of inertia (Ixy and Ixz) and reduce α y and α z Even when x is set to zero, there is still angular acceleration of the golf club head about the x-axis 1050, which results in unwanted side spin from the ball launch parameters of the golf club head 100 for both high and low face hits.

[0066] Referring to Figures 10-13 and equations (2)-(4) for a wood-type golf club head (having negative Ixy and Ixz products of inertia), when a golfer strikes the ball in the center of the club face (heel-to-toe direction), but strikes the ball just below or just above the center of the striking face (crown-to-sole direction), the club head 100 experiences a lofting moment, resulting in rotational acceleration about all three axes.

[0067] In many embodiments, the club head 100 has a flexural strength of approximately 30 g·cm 2 Larger than approx. 40g·cm 2 Larger than 50g cm 2 Larger than approx. 60g·cm 2 Larger than approx. 70g·cm 2 Larger than approx. 80g·cm 2 Larger than approx. 90g·cm 2 Larger than approx. 100g·cm 2 Larger than approx. 110g·cm 2 Larger than approx. 120g·cm 2 Larger than approx. 130g·cm 2 Larger than approx. 140g·cm 2 Larger than approx. 150g·cm 2 Larger than approx. 160g·cm 2 Larger than approx. 170g·cm 2Larger than approx. 180g·cm 2 Larger than approx. 190g·cm 2 Greater than, or about 200 g·cm 2 Contains Ixy products of inertia greater than

[0068] In many embodiments, the club head 100 has a flexural strength of approximately -200 g·cm 2 Larger than approx. -190g·cm 2 Larger than approx. -180g·cm 2 Larger than approx. -170g·cm 2 Larger than approx. -160g·cm 2 Larger than approx. -150g·cm 2 Larger than approx. -140g·cm 2 Larger than approx. -130g·cm 2 Larger than approx. -120g·cm 2 Larger than approx. -110g·cm 2 Larger than about -100g·cm 2 Larger than about -90g·cm 2 Larger than about -80g·cm 2 Larger than about -70g·cm 2 Larger than about -60g·cm 2 Larger than about -50g·cm 2 Larger than about -40g·cm 2 Greater than, or about -30g·cm 2 contains a product of inertia Ixz greater than

[0069] Referring to Figures 10 and 12, when the golf club head 100 is struck below the center of the striking face and Ixy is negative, the club head experiences a delofting moment. This delofting moment creates a closure rotation caused by Ixz, which imparts fade spin to the golf ball. Referring to Figures 11 and 13, when the golf club head is struck above the center of the striking face and Ixy is negative, the club head experiences a lofting moment. This lofting moment creates an open rotation and a toe-up rotation of the golf club head, which imparts draw spin to the golf ball. The magnitude of this side spin is determined by α y (and hence Ixy and τ x ) When Ixy is made positive, the resulting side spin behavior for high and low face hits is opposite (i.e., high face hits will result in a slice, while low face hits will result in a hook).

[0070] Varying the magnitude of the products of inertia can significantly affect the head rotational acceleration (Equations (2)-(4)) of the golf club head at impact when the golf ball is struck above or below the center of the club face. The products of inertia can be optimized to eliminate harmful side spin caused by closure rates for hits low and high on the striking face. These products of inertia can be added to and optimized with the moment of inertia and CG positioning to provide a golf club head with a lower and rearward CG, a high moment of inertia (heel-to-toe forgiveness), and forgiveness above and below the center of the striking face. Additionally, the aerodynamics of the club head 100 can be further balanced with respect to the CG and moment of inertia for the ultimate in balanced golf club performance.

[0071] As mentioned above, zeroing the products of inertia Ixy and Ixz eliminates angular acceleration about the y-axis 1060 and z-axis 1070 (α y and α z =0). However, as previously discussed, side spin is still generated due to differences in face angle and club path. Referring to FIG. 14A, the side spin generated by a driver-type golf club head on above- and below-center hits (with desirable launch parameters) is shown. The more above- or below-center the ball is hit, the more side spin is generated. This side spin can result in shots that do not travel the desired length or direction.

[0072] To counteract this unwanted side spin that is generated, the Ixy product of inertia is maximized (greater than zero) to create a favorable angular acceleration about the y-axis (α y ) can be generated. The maximized Ixy products of inertia can be used to eliminate side spin created by the difference between face angle and club path for high and low face hits. Referring to FIG. 14B, it can be seen that a theoretical golf club head with improved products of inertia can eliminate side spin created by above- and below-center hits, resulting in a golf shot with consistent distance and direction (no side spin). III. Center of gravity and moment of inertia

[0073] The golf club head 100 includes a low, rearward CG balanced against high moments of inertia (Ixx, Iyy, Izz) while maximizing the Ixy products of inertia and near-zeroing the Ixz products of inertia. In many embodiments, the low, rearward club head CG and increased moments of inertia can be achieved by increasing discretionary weight and relocating the discretionary weight to areas of the club head that maximize the distance from the head CG. Increasing discretionary weight can be achieved by thinning the crown and / or using optimized materials relative to the head CG location, as described above. Relocating discretionary weight to maximize the distance from the head CG can be achieved by using removable weights, recessed weights, or a steep crown angle relative to the head CG location, as described above.

[0074] In many embodiments, the club head 100 has a flexural mass of approximately 2250 g·cm 2 Larger than 2500g·cm 2 Larger than 2750g·cm 2 Larger than 3000g cm 2 Larger than 3250g·cm 2 Larger than 3500g·cm 2 Larger than approx. 3750g·cm 2 Larger than 4000g cm 2 Larger than approx. 4250g·cm 2 Larger than 4500g·cm 2 Larger than approx. 4750g·cm 2 Larger than 5000g cm 2 Larger than 5250g·cm 2 Larger than 5500g·cm 2 Larger than approx. 5750g·cm 2 Larger than approx. 6000g·cm 2 Larger than approx. 6250g·cm 2 Larger than approx. 6500g·cm 2 Larger than approx. 6750g·cm2 Greater than, or about 7000 g·cm 2 Including the crown-sole moment of inertia Ixx, which is greater than

[0075] In many embodiments, the club head 100 has a compressive strength of approximately 4500 g·cm 2 Larger than approx. 4750g·cm 2 Larger than 5000g cm 2 Larger than 5250g·cm 2 Larger than 5500g·cm 2 Larger than approx. 5750g·cm 2 Larger than approx. 6000g·cm 2 Larger than approx. 6250g·cm 2 Larger than approx. 6500g·cm 2 Larger than approx. 6750g·cm 2 Greater than, or about 7000 g·cm 2 including a heel-toe moment of inertia Iyy, which is greater than

[0076] In many embodiments, the club head 100 has a compressive strength of approximately 7000 g·cm 2 Larger than approx. 7250g·cm 2 Larger than approx. 7500g·cm 2 Larger than approx. 7750g·cm 2 Greater than 8000g·cm 2 Greater than 8500g·cm 2 Larger than 8750g·cm 2 Greater than 9000g·cm 2 Larger than 9250g·cm 2 Greater than 9500g·cm 2 Greater than 9750g·cm 2 Greater than 10,000 g·cm 2 Greater than 10250g·cm 2 Greater than 10500g·cm 2 Greater than 10750g·cm 2 Greater than 11000g·cm 2Greater than 11250g·cm 2 Greater than 11500g·cm 2 Larger than 11750g·cm 2 Greater than 12000g·cm 2 Greater than 12500g·cm 2 Greater than 13000g·cm 2 Greater than 13500g·cm 2 Greater than or equal to 14000 g·cm 2 The composite moment of inertia (i.e., the sum of the crown-sole moment of inertia Ixx and the heel-toe moment of inertia Iyy) is greater than

[0077] In many embodiments, the club head 100 has a head CG height 374 that is less than about 0.20 inches, less than about 0.15 inches, less than about 0.10 inches, less than about 0.09 inches, less than about 0.08 inches, less than about 0.07 inches, less than about 0.06 inches, or less than about 0.05 inches. Additionally, in many embodiments, the club head 100 includes a head CG height 374 that has an absolute value of less than about 0.20 inches, less than about 0.15 inches, less than about 0.10 inches, less than about 0.09 inches, less than about 0.08 inches, less than about 0.07 inches, less than about 0.06 inches, or less than about 0.05 inches.

[0078] In many embodiments, the club head 100 includes a head CG depth 172 that is greater than about 1.2 inches, greater than about 1.3 inches, greater than about 1.4 inches, greater than about 1.5 inches, greater than about 1.6 inches, greater than about 1.7 inches, greater than about 1.8 inches, greater than about 1.9 inches, or greater than about 2.0 inches.

[0079] In some embodiments, the club head 100 can include a first performance characteristic. The first performance characteristic is defined as the ratio between (a) the difference between 72 mm and the face height 144 and (b) the head CG depth 172. In many embodiments, the first performance characteristic is 0.56 or less. However, in some embodiments, the first performance characteristic is 0.60 or less, 0.65 or less, 0.70 or less, or 0.75 or less.

[0080] In some embodiments, club head 100 can include a second performance characteristic. The second performance characteristic is defined as the sum of (a) the volume of club head 100 and (b) the ratio between the absolute value of head CG depth 172 and head CG height 174. The second performance characteristic is 425 cc or greater. In some embodiments, the second performance characteristic can be 450 cc or greater, 475 cc or greater, 490 cc or greater, 495 cc or greater, 500 cc or greater, 505 cc or greater, or 510 cc or greater.

[0081] A club head 100 with a reduced head CG height 174 can reduce the backspin of a golf ball at impact compared to a similar club head with a higher head CG height. In many embodiments, reducing backspin can increase both ball speed and flight distance for improved club head performance. Additionally, a club head 100 with an increased head CG depth 172 can increase the heel-toe moment of inertia compared to a similar club head with a head CG depth closer to the ball striking surface. Increasing the heel-toe moment of inertia can increase the club head's forgiveness at impact for improved club head performance. Additionally, a club head 100 with an increased head CG depth 172 can increase the club head's dynamic loft at impact compared to a similar club head with a head CG depth closer to the ball striking surface, thereby increasing the launch angle of the golf ball at impact.

[0082] Head CG height 174 and / or head CG depth 172 can be achieved by reducing the weight of the club head in various areas, thereby increasing discretionary weight, and altering the discretionary weight in strategic areas of the club head to shift the head CG lower and more rearward. Various means for reducing and repositioning club head weight are described below. i. Thin areas

[0083] In some embodiments, head CG height 174 and / or head CG depth 172 can be achieved by thinning and removing excess weight in various areas of club head 100. Removing excess weight provides increased discretionary weight that can be strategically repositioned in areas of club head 100 to achieve a desired low and rearward club head CG position.

[0084] In many embodiments, the club head 100 can have one or more thin regions 176. The one or more thin regions 176 can be located on the striking face 104, the body 102, or a combination of the striking face 104 and the body 102. Furthermore, the one or more thin regions 176 can be located in any region of the body 102, including the crown 116, the sole 118, the heel 120, the toe 122, the front end 108, the back end 110, the skirt 128, or any combination of the listed locations. For example, in some embodiments, the one or more thin regions 176 can be located on the crown 116. In a further example, the one or more thin regions 176 can be located on a combination of the striking face 104 and the crown 106. In a further example, the one or more thin regions 176 can be located on a combination of the striking face 104, the crown 116, and the sole 118. In a further example, the entire body 102 and / or the entire striking face 104 can include a thin region 176.

[0085] In embodiments in which one or more thinned regions 176 are disposed on the striking face 104, the thickness of the striking face 104 can vary, with a maximum striking face thickness and a minimum striking face thickness. In these embodiments, the minimum striking face thickness can be less than 0.10 inches, less than 0.09 inches, less than 0.08 inches, less than 0.07 inches, less than 0.06 inches, less than 0.05 inches, less than 0.04 inches, or less than 0.03 inches. In these or other embodiments, the maximum striking face thickness can be less than 0.20 inches, less than 0.19 inches, less than 0.18 inches, less than 0.17 inches, less than 0.16 inches, less than 0.15 inches, less than 0.14 inches, less than 0.13 inches, less than 0.12 inches, less than 0.11 inches, or less than 0.10 inches.

[0086] In embodiments in which one or more thinned regions 176 are disposed on body 102, the thinned regions can include a thickness of less than about 0.020 inches. In other embodiments, the thinned regions can include a thickness of less than 0.025 inches, less than 0.020 inches, less than 0.019 inches, less than 0.018 inches, less than 0.017 inches, less than 0.016 inches, less than 0.015 inches, less than 0.014 inches, less than 0.013 inches, less than 0.012 inches, or less than 0.010 inches. For example, the thinned regions can include a thickness of about 0.010-0.025 inches, about 0.013-0.020 inches, about 0.014-0.020 inches, about 0.015-0.020 inches, about 0.016-0.020 inches, about 0.017-0.020 inches, or about 0.018-0.020 inches.

[0087] In the illustrated embodiment, the thinned regions 176 vary in shape and location and cover approximately 25% of the surface area of ​​the club head 100. In other embodiments, the thinned regions may cover approximately 20-30%, approximately 15-35%, approximately 15-25%, approximately 10-25%, approximately 15-30%, or approximately 20-50% of the surface area of ​​the club head 900. Additionally, in other embodiments, the thinned regions may cover up to 5%, up to 10%, up to 15%, up to 20%, up to 25%, up to 30%, up to 35%, up to 40%, up to 45%, or up to 50% of the surface area of ​​the club head 100.

[0088] In many embodiments, crown 116 can include one or more thin regions 176, such that about 51% of the surface area of ​​crown 116 includes thin regions 176. In other embodiments, crown 116 can include one or more thin regions 176, such that up to 20%, up to 25%, up to 30%, up to 35%, up to 40%, up to 45%, up to 50%, up to 55%, up to 60%, up to 65%, up to 70%, up to 75%, up to 80%, up to 85%, or up to 90% of crown 116 includes thin regions 176. For example, in some embodiments, about 40-60% of crown 116 can include thin regions 176. By way of further example, in other embodiments, about 50-100%, about 40-80%, about 35-65%, about 30-70%, or about 25-75% of crown 116 can include thin regions 176. In some embodiments, crown 116 can include one or more thin regions 176, each of which has a tapered thickness. In this exemplary embodiment, crown 116's one or more thin regions 176 extend in a heel-to-toe direction, with each of one or more thin regions 176 decreasing in thickness in a direction from striking face 104 toward back end 110.

[0089] In many embodiments, sole 118 can include one or more thin regions 176, such that approximately 64% of the surface area of ​​sole 118 includes thin regions 176. In other embodiments, sole 118 can include one or more thin regions 176, such that up to 20%, up to 25%, up to 30%, up to 35%, up to 40%, up to 45%, up to 50%, up to 55%, up to 60%, up to 65%, up to 70%, up to 75%, up to 80%, up to 85%, or up to 90% of sole 118 includes thin regions 176. For example, in some embodiments, approximately 40-60% of sole 118 can include thin regions 176. By way of further example, in other embodiments, approximately 50-100%, approximately 40-80%, approximately 35-65%, approximately 30-70%, or approximately 25-75% of sole 118 can include thin regions 176.

[0090] Thin regions 176 can include any shape, such as a circle, a triangle, a square, a rectangle, an oval, or any other polygon or shape having at least one curved side. Additionally, one or more thin regions 176 can include the same shape as the remaining thin regions or a different shape.

[0091] In many embodiments, the club head 100 having the thinned regions can be manufactured using centrifugal casting. In these embodiments, centrifugal casting allows the club head 100 to have thinner walls than club heads manufactured using traditional casting. In other embodiments, the portions of the club head 100 having the thinned regions can be manufactured using other suitable methods, such as stamping, forging, or machining. In embodiments in which the portions of the club head 100 having the thinned regions are manufactured using stamping, forging, or machining, the portions of the club head 100 can be joined using epoxy, tape, welding, mechanical fasteners, or other suitable methods. ii. Optimized materials

[0092] The golf club head 100 can further optimize the CG height 174 and / or CG depth 172 using optimized materials in the striking face 104 and / or body 102. The optimized materials can include increased specific strength and / or increased specific flexibility. The specific flexibility is measured as the ratio of the yield strength to the modulus of elasticity of the optimized material. Increasing the specific strength and / or specific flexibility can allow portions of the club head (such as portions of the striking face 104 and / or body 102) to be thinner while maintaining durability.

[0093] The golf club head 100 includes a first material and a second material. In most embodiments, the striking face 104 includes the first material and the body 102 includes the second material. In most embodiments, the first material is different from the second material, but in some embodiments, the first material can be the same as the second material.

[0094] In some embodiments, the first material of the striking face 104 can be an optimized material as described in U.S. Provisional Patent Application No. 62 / 399,929, entitled "Golf Club Head With Optimized Material Properties," which is incorporated herein by reference in its entirety. In these or other embodiments, the first material, including an optimized titanium alloy, can have a resistance of approximately 900,000 PSI / lb / in. 3 (224MPa / g / cm 3 ) or more, approximately 910,000 PSI / lb / in 3 (227MPa / g / cm 3 ) or more, approximately 920,000PSI / lb / in 3 (229MPa / g / cm 3 ) or more, approximately 930,000PSI / lb / in 3 (232MPa / g / cm 3 ) or more, approximately 940,000PSI / lb / in 3 (234MPa / g / cm 3 ) or more, approximately 950,000PSI / lb / in 3 (237MPa / g / cm 3) or more, approximately 960,000PSI / lb / in 3 (239MPa / g / cm 3 ) or more, approximately 970,000PSI / lb / in 3 (242MPa / g / cm 3 ) or more, approximately 980,000PSI / lb / in 3 (244MPa / g / cm 3 ) or more, approximately 990,000PSI / lb / in 3 (247MPa / g / cm 3 ) or more, approximately 1,000,000PSI / lb / in 3 (249MPa / g / cm 3 ) or more, approximately 1,050,000PSI / lb / in 3 (262MPa / g / cm 3 ) or more, approximately 1,100,000PSI / lb / in 3 (274MPa / g / cm 3 ) or more, or approximately 1,150,000 PSI / lb / in 3 (286MPa / g / cm 3 ) or more.

[0095] Additionally, in these or other embodiments, the first material comprising an optimized titanium alloy can have a relative flexibility of about 0.0075 or greater, about 0.0080 or greater, about 0.0085 or greater, about 0.0090 or greater, about 0.0091 or greater, about 0.0092 or greater, about 0.0093 or greater, about 0.0094 or greater, about 0.0095 or greater, about 0.0096 or greater, about 0.0097 or greater, about 0.0098 or greater, about 0.0099 or greater, about 0.0100 or greater, about 0.0105 or greater, about 0.0110 or greater, about 0.0115 or greater, or about 0.0120 or greater.

[0096] In these or other embodiments, the first material comprising an optimized steel alloy has a resistance of about 650,000 PSI / lb / in 3 (162MPa / g / cm 3 ) or more, approximately 700,000PSI / lb / in 3 (174MPa / g / cm 3 ) or more, approximately 750,000PSI / lb / in 3(187MPa / g / cm 3 ) or more, approximately 800,000PSI / lb / in 3 (199MPa / g / cm 3 ) or more, approximately 810,000PSI / lb / in 3 (202MPa / g / cm 3 ) or more, approximately 820,000PSI / lb / in 3 (204MPa / g / cm 3 ) or more, approximately 830,000PSI / lb / in 3 (207MPa / g / cm 3 ) or more, approximately 840,000PSI / lb / in 3 (209MPa / g / cm 3 ) or more, approximately 850,000PSI / lb / in 3 (212MPa / g / cm 3 ) or more, approximately 900,000PSI / lb / in 3 (224MPa / g / cm 3 ) or more, approximately 950,000PSI / lb / in 3 (237MPa / g / cm 3 ) or more, approximately 1,000,000PSI / lb / in 3 (249MPa / g / cm 3 ) or more, approximately 1,050,000PSI / lb / in 3 (262MPa / g / cm 3 ) or more, approximately 1,100,000PSI / lb / in 3 (274MPa / g / cm 3 ) or more, approximately 1,115,000PSI / lb / in 3 (278MPa / g / cm 3 ) or more, or approximately 1,120,000 PSI / lb / in 3 (279MPa / g / cm 3 ) or more.

[0097] Additionally, in these or other embodiments, the first material comprising the optimized steel alloy can have a specific flexibility of about 0.0060 or greater, about 0.0065 or greater, about 0.0070 or greater, about 0.0075 or greater, about 0.0080 or greater, about 0.0085 or greater, about 0.0090 or greater, about 0.0095 or greater, about 0.0100 or greater, about 0.0105 or greater, about 0.0110 or greater, about 0.0115 or greater, about 0.0120 or greater, about 0.0125 or greater, about 0.0130 or greater, about 0.0135 or greater, about 0.0140 or greater, about 0.0145 or greater, or about 0.0150 or greater.

[0098] In these embodiments, the increased strength-to-weight ratio and / or increased flexibility-to-weight ratio of the optimized first material allows for the striking face 104, or portions thereof, to be thinned while maintaining durability, as described above. By thinning the striking face 104, the weight on the striking face can be reduced, thereby increasing discretionary weight that can be strategically placed in other areas of the club head 100, thereby positioning the head CG lower and further back and / or increasing the club head's moment of inertia.

[0099] In some embodiments, the second material of the body 102 can be an optimized material as described in U.S. Provisional Patent Application No. 62 / 399,929, entitled "Golf Club Head With Optimized Material Properties," which is incorporated herein by reference in its entirety. In these or other embodiments, the second material, which comprises an optimized titanium alloy, can have a resistance of approximately 730,500 PSI / lb / in. 3 (182MPa / g / cm 3 ) or greater. For example, the specific strength of an optimized titanium alloy is approximately 650,000 PSI / lb / in 3 (162MPa / g / cm 3 ) or more, approximately 700,000PSI / lb / in 3 (174MPa / g / cm 3 ) or more, approximately 750,000PSI / lb / in 3 (187MPa / g / cm 3 ) or more, approximately 800,000PSI / lb / in 3(199MPa / g / cm 3 ) or more, approximately 850,000PSI / lb / in 3 (212MPa / g / cm 3 ) or more, approximately 900,000PSI / lb / in 3 (224MPa / g / cm 3 ) or more, approximately 950,000PSI / lb / in 3 (237MPa / g / cm 3 ) or more, approximately 1,000,000PSI / lb / in 3 (249MPa / g / cm 3 ) or more, approximately 1,050,000PSI / lb / in 3 (262MPa / g / cm 3 ) or more, or approximately 1,100,000 PSI / lb / in 3 (272MPa / g / cm 3 ) or more.

[0100] Additionally, in these or other embodiments, the second material comprising an optimized titanium alloy can have a relative flexibility of about 0.0060 or greater, about 0.0065 or greater, about 0.0070 or greater, about 0.0075, about 0.0080 or greater, about 0.0085 or greater, about 0.0090 or greater, about 0.0095 or greater, about 0.0100 or greater, about 0.0105 or greater, about 0.0110 or greater, about 0.0115 or greater, or about 0.0120 or greater.

[0101] In these or other embodiments, the second material comprising optimized steel has a resistance of about 500,000 PSI / lb / in 3 (125MPa / g / cm 3 ) or more, approximately 510,000PSI / lb / in 3 (127MPa / g / cm 3 ) or more, approximately 520,000PSI / lb / in 3 (130MPa / g / cm 3 ) or more, approximately 530,000PSI / lb / in 3 (132MPa / g / cm 3 ) or more, approximately 540,000PSI / lb / in 3 (135MPa / g / cm 3) or more, approximately 550,000PSI / lb / in 3 (137MPa / g / cm 3 ) or more, approximately 560,000PSI / lb / in 3 (139MPa / g / cm 3 ) or more, approximately 570,000PSI / lb / in 3 (142MPa / g / cm 3 ) or more, approximately 580,000PSI / lb / in 3 (144MPa / g / cm 3 ) or more, approximately 590,000PSI / lb / in 3 (147MPa / g / cm 3 ) or more, approximately 600,000PSI / lb / in 3 (149MPa / g / cm 3 ) or more, approximately 625,000PSI / lb / in 3 (156MPa / g / cm 3 ) or more, approximately 675,000PSI / lb / in 3 (168MPa / g / cm 3 ) or more, approximately 725,000PSI / lb / in 3 (181MPa / g / cm 3 ) or more, approximately 775,000PSI / lb / in 3 (193MPa / g / cm 3 ) or more, approximately 825,000PSI / lb / in 3 (205MPa / g / cm 3 ) or more, approximately 875,000PSI / lb / in 3 (218MPa / g / cm 3 ) or more, approximately 925,000PSI / lb / in 3 (230MPa / g / cm 3 ) or more, approximately 975,000PSI / lb / in 3 (243MPa / g / cm 3 ) or more, approximately 1,025,000PSI / lb / in 3 (255MPa / g / cm 3 ) or more, approximately 1,075,000PSI / lb / in 3 (268MPa / g / cm 3 ), or approximately 1,125,000 PSI / lb / in 3 (280MPa / g / cm3 ) or more.

[0102] Additionally, in these or other embodiments, the second material comprising optimized steel can have a specific flexibility of about 0.0060 or greater, about 0.0062 or greater, about 0.0064 or greater, about 0.0066 or greater, about 0.0068 or greater, about 0.0070 or greater, about 0.0072 or greater, about 0.0076 or greater, about 0.0080 or greater, about 0.0084 or greater, about 0.0088 or greater, about 0.0092 or greater, about 0.0096 or greater, about 0.0100 or greater, about 0.0105 or greater, about 0.0110 or greater, about 0.0115 or greater, about 0.0120 or greater, about 0.0125 or greater, about 0.0130 or greater, about 0.0135 or greater, about 0.0140 or greater, about 0.0145 or greater, or about 0.0150 or greater.

[0103] In some embodiments, the second material can include a composite formed of a polymer resin and reinforcing fibers or composites. The polymer resin can include a thermosetting resin or a thermoplastic resin. More specifically, in embodiments having a thermoplastic resin, the resin can include a thermoplastic polyurethane (TPU) or a thermoplastic elastomer (TPE). For example, the resin can include polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyimide, polyamide such as PA6 or PA66, polyamideimide, polyphenylene sulfide (PPS), polycarbonate, engineering polyurethane, and / or other similar materials. The reinforcing fibers can include carbon fiber (or chopped carbon fiber), glass fiber (or chopped glass fiber), graphite fiber (or chopped graphite fiber), or any other suitable filler material. In other embodiments, the composite can include beads (e.g., glass beads, metal beads) or powder (e.g., tungsten powder) for weighting. In other embodiments, the composite may include any reinforcing filler that enhances strength, durability, and / or load capacity.

[0104] The polymer resin should preferably incorporate one or more polymers with sufficiently high material strength and / or strength-to-weight ratio properties to withstand typical use while providing a lightweight design. Specifically, it is important that the design and materials efficiently withstand the stresses imposed during impact between the striking face 104 and the golf ball while not substantially contributing to the overall weight of the golf club head 100. Generally, polymers can be characterized by a tensile strength at yield greater than about 60 MPa. The resulting composite, combining the polymer resin and reinforcing fibers, can have a tensile strength at yield greater than about 110 MPa, greater than about 180 MPa, greater than about 220 MPa, greater than about 260 MPa, greater than about 280 MPa, or greater than about 290 MPa. In some embodiments, suitable composites can have a tensile strength at yield of about 60 MPa to about 350 MPa.

[0105] In some embodiments, the reinforcing fibers comprise a plurality of dispersed discontinuous fibers (i.e., "chopped fibers"). In some embodiments, the reinforcing fibers comprise a plurality of discontinuous "long fibers" having a design fiber length of about 3 mm to about 25 mm. For example, in some embodiments, the fiber length is about 12.7 mm (0.5 inches) before the molding process. In other embodiments, the reinforcing fibers comprise discontinuous "short fibers" having a design fiber length of about 0.01 mm to about 3 mm. It should be noted that in either case (short or long fibers), the given length is a premixed length, and some fibers may actually be shorter than the stated range in the final component due to shearing during the molding process. In some configurations, the discontinuous chopped fibers may be characterized by an aspect ratio (e.g., fiber length / diameter) greater than about 10, or more preferably greater than about 50, and less than about 1500. In a particular configuration, regardless of the particular type of discontinuous chopped fibers used, the composite may have a fiber length of from about 0.01 mm to about 25 mm.

[0106] The composite may have a polymer resin content of about 40% to about 90% by weight, or about 55% to about 70% by weight. The second component composite may have a fiber content of between about 10% to about 60% by weight. In some embodiments, the composite has a fiber content of between about 20% to about 50% by weight, or between 30% to 40% by weight. In some embodiments, the composite has a fiber content of between about 10% to about 15%, between about 15% to about 20%, between about 20% to about 25%, between about 25% to about 30%, between about 30% to about 35%, between about 35% to about 40%, between about 40% to about 45%, between about 45% to about 50%, between about 50% to about 55%, or between about 55% to about 60% by weight.

[0107] The density of the composite forming the second component can range from about 1.15 g / cc to about 2.02 g / cc. In some embodiments, the density of the composite ranges from about 1.30 g / cc to about 1.40 g / cc or from about 1.40 g / cc to about 1.45 g / cc. The composite can have a melting temperature of between about 210°C and about 280°C. In some embodiments, the composite can have a melting temperature of between about 250°C and about 270°C.

[0108] In some embodiments, the composite comprises a long-fiber reinforced TPU. The long-fiber TPU can comprise approximately 40% long carbon fiber by weight. The long-fiber TPU can exhibit a high modulus of elasticity, which is greater than that of short-carbon fiber composites. The long-fiber TPU can withstand high temperatures, making it suitable for use in golf club heads used and / or stored in hot climates. The long-fiber TPU also exhibits high toughness, allowing it to function well as a replacement for traditional metal components. In some embodiments, the long-fiber TPU comprises a tensile modulus of between about 26,000 MPa and about 30,000 MPa, or between about 27,000 MPa and about 29,000 MPa. In some embodiments, the long-fiber TPU comprises a flexural modulus of between about 21,000 MPa and about 26,000 MPa, or between about 22,000 MPa and 25,000 MPa. The long fiber TPU material can exhibit a tensile elongation (at break) of between about 0.5% and about 2.5%. In some embodiments, the tensile elongation of the composite TPU material can be between about 1.0% and about 2.0%, between about 1.2% and about 1.4%, between about 1.4% and about 1.6%, between about 1.6% and about 1.8%, or between about 1.8% and about 2.0%.

[0109] While strength and weight are two primary properties to consider for composites, suitable composites may also offer secondary benefits. For example, PPS and PEEK are two exemplary thermoplastic polymers that meet the strength and weight requirements of this design. However, unlike many other polymers, the use of PPS or PEEK is further advantageous due to their unique acoustic properties. Specifically, PPS and PEEK generally emit a metallic acoustic response upon impact in many situations. Therefore, by using a PPS or PEEK polymer, this design can take advantage of the strength / weight benefits of the polymer without losing the desirable metallic clubhead sound upon impact.

[0110] In many embodiments, the second material of the golf club head 100 can be formed by injection molding. The second material can be injection molded from a composite including both a polymer resin and reinforcing fibers to form the body portion 102. The reinforcing fibers can be embedded in the resin prior to molding the second component. The composite including both the resin and fibers can be provided in the form of pellets. The pellets can be melted and injected into an empty mold to form the second component. In other embodiments, the second component can be obtained by extrusion, injection blow molding, 3D printing, or any other suitable molding means.

[0111] In embodiments using injection molding, the temperature of the mold used to form the second component from the composite can ideally be maintained between about 60°C and 90°C. For example, the mold temperature can be about 75°C. In an alternative embodiment, the second material may include a fiber-reinforced composite (FRC) material. FRC materials generally include one or more layers of unidirectional or multidirectional fiber fabrics extending across the majority of the polymer. The maximum dimensions of the fibers used in FRC differ from those used in filled thermoplastic (FT) materials, which can be substantially larger / longer than the reinforcing fibers used in FT materials and can have sufficient size and properties to be provided as a continuous fabric separate from the polymer. When formed using a thermoplastic polymer, even if the polymer is freely flowable when melted, the continuous fibers contained therein generally are not freely flowable.

[0112] FRC materials are generally formed by arranging fibers in a desired configuration and then impregnating the fiber material with a sufficient amount of polymer material to provide rigidity. Thus, FRC materials may have a resin content greater than about 45% by volume, or more preferably greater than about 55% by volume, while FRC materials desirably have a resin content less than about 45% by volume, or more preferably less than about 35% by volume. FRC materials traditionally use two-part thermosetting epoxies as the polymer matrix, although thermoplastic polymers can also be used as the matrix. Often, FRC materials are pre-prepared before final fabrication, and such intermediate materials are often referred to as prepregs. When using thermosetting polymers, the prepreg is partially cured in an intermediate shape, with final curing occurring once the prepreg is molded into the final shape. When using thermoplastic polymers, the prepreg can include a cooled thermoplastic matrix, which can then be heated and molded into the final shape.

[0113] The second material may be substantially formed of a molded fiber-reinforced composite, including a reinforcing layer of glass or carbon fiber embedded in a polymer matrix. In such embodiments, the polymer matrix is ​​preferably a thermoplastic material. In some embodiments, the thermoplastic material is a thermoplastic polyurethane (TPU), such as polyphenylene sulfide (PPS), polyetheretherketone (PEEK), or a polyamide, such as PA6 or PA66. In other embodiments, the second material may be formed of a filled thermoplastic material, including a filler of glass beads or discontinuous glass, carbon, or aramid polymer fibers embedded throughout the thermoplastic material. The thermoplastic material (base resin) may be a TPU, such as polyphenylene sulfide (PPS), polyetheretherketone (PEEK), or a polyamide. However, in other embodiments, the second material forming the body 102 may have a mixed material composition, including both a filled thermoplastic material and a molded fiber-reinforced composite.

[0114] The body 102 may have a mixed material construction including both a fiber-reinforced thermoplastic composite elastic layer (not shown) and a molded thermoplastic structural layer (not shown). In some preferred embodiments, the molded thermoplastic structural layer may be formed of a filled thermoplastic material including glass beads or discontinuous glass, carbon, or aramid polymer fiber fillers embedded throughout the thermoplastic material. The thermoplastic material may be a TPU such as polyphenylene sulfide (PPS), polyetheretherketone (PEEK), or a polyamide such as PA6 or PA66. The elastic layer may then include a reinforcing woven layer of glass, carbon fiber, or aramid polymer fiber embedded in a thermoplastic polymer matrix. The thermoplastic polymer matrix may include a TPU such as polyphenylene sulfide (PPS), polyetheretherketone (PEEK), or a polyamide such as PA6 or PA66. In one particular embodiment, the elastic layer of the body 102 may include a woven carbon fiber fabric embedded in polyphenylene sulfide (PPS). The structural layer of the body 102 may include a filled polyphenylene sulfide (PPS) polymer.

[0115] In these embodiments, the increased specific strength and / or increased specific flexibility of the optimized second material allows the body 102, or portions thereof, to be thinner while maintaining durability. A thinner body allows for less weight in the club head, thereby increasing discretionary weight to be strategically placed in other areas of the club head 100, thereby positioning the head CG lower and further back and / or increasing the club head's moment of inertia. iii. Removable weights

[0116] In some embodiments, the club head 100 can include one or more weight structures 180 including one or more removable weights 182. The one or more weight structures 180 and / or the one or more removable weights 182 can be positioned toward the sole 118 and back end 110, thereby allowing discretionary weights to be positioned near the sole 118 and back end 110 of the club head to achieve a low, rearward head CG position. In some embodiments, the one or more weight structures 180 can be positioned in the high toe 122 near the crown 116 and in the low heel 120 near the sole 118 to increase the product of inertia Ixy, balance the product of inertia Ixz, or maintain a low CG with a high MOI. In many embodiments, the one or more weight structures 180 removably receive one or more removable weights 182. In these embodiments, one or more removable weights 182 may be coupled to one or more weight structures 180 using any suitable method, such as threaded fasteners, adhesives, magnets, snap fits, or any other mechanism capable of securing one or more removable weights to one or more weight structures.

[0117] The weight structures 180 and / or removable weights 182 may be positioned relative to a clock grid 2000 that can be aligned with respect to the striking face 104 when viewed from a top or bottom view ( FIG. 3 ). The clock grid includes at least a 12 o'clock line, a 2 o'clock line, a 3 o'clock line, a 4 o'clock line, a 5 o'clock line, a 6 o'clock line, a 7 o'clock line, an 8 o'clock line, a 9 o'clock line, a 10 o'clock line, and an 11 o'clock line. For example, the clock grid 2000 includes a 12 o'clock line 2012 that is aligned with the geometric center 140 of the striking face 104. The 12 o'clock line 2012 is orthogonal to the X'Y' plane. The clock grid 2000 can be centered along the 12 o'clock line 2012 at the midpoint between the front end 108 and the back end 110 of the club head 100. In the same or other examples, clock grid center point 2020 can be centered near the geometric center point of golf club head 100 when viewed from a bottom view ( FIG. 3 ). Clock grid 2000 also includes a 3 o'clock line 2003 extending toward the heel 120 of club head 100 and a 9 o'clock line 2009 extending toward the toe 122 of club head 100. Furthermore, clock grid 2000 extends completely from crown 116 to the sole in the direction of y-axis 1060. Clock grid 2000 dissects golf club head 100 into 12 separate sections of the golf club head.

[0118] In examples such as this example (FIG. 3), golf club head 100 includes one or more weights 182 positioned between 11 o'clock line 2011 and 9 o'clock line 2009. Additionally, golf club head 100 may include one or more weights 182 positioned between 3 o'clock line 2003 and 5 o'clock line 2005. While one or more weights 182 may be positioned on an exterior surface of the club head (crown or sole), one or more weights 182 may extend into or be defined within club head 100. In some examples, the location of weight structure 180 may be established with respect to a larger area. For example, in such an example, weight structure 180 and weights 182 may be positioned near toe 122 and crown 116 and may be at least partially enclosed between 11 o'clock line 2011 and 9 o'clock line 2009 of clock grid 2000 and intersect 10 o'clock line 2010. Further, in one example, weight structure 180 and weights 182 may be positioned near heel 120 and sole 118 and may be at least partially enclosed between 3 o'clock line 2003 and 5 o'clock line 2005 of clock grid 2000 and intersect 4 o'clock line 2004. These weights may also be used to address a balance between low rear CG, high MOI, maximized Ixy products of inertia, and balanced Ixz products of inertia.

[0119] In some embodiments, not shown, the golf club can have additional weight between the 3 o'clock line 2003 and the 9 o'clock line to lower (or deepen) the CG 170 or to increase the Ixx or Iyy moments of inertia. The additional weight can be used to change the balance of the moments of inertia, products of inertia, and CG position to provide a desired inertia tensor and CG position. In some examples, additional weight can be placed between the 4 o'clock line 2004 and the 7 o'clock line 2007 to deepen the CG 170 and increase the Iyy moments of inertia. In another example, additional weight can be placed between the 5 o'clock line 2005 and the 8 o'clock line 2008.

[0120] In this example, weight structure 180 protrudes inward from the exterior contour of sole 118 toward the crown. In some examples, weight structure 180 can include a mass between about 2 grams and about 50 grams and / or a volume between about 1 cc and about 30 cc. In other examples, weight structure 180 can be positioned flush with the exterior contour of body 102.

[0121] In many embodiments, the one or more weights 182 can include a mass between about 0.5 grams and about 30 grams and can be replaced with one or more other similar removable weights to adjust the position of the head CG 370. In the same or other examples, the weight center 186 can include at least one of the center of gravity of the one or more weights 182 and / or the geometric center of the one or more weights 182.

[0122] 19-22, golf club head 300 includes a heel weight assembly 330 and a toe weight assembly 331 attached to body 302 (similar to body 102 of golf club 100). Heel weight assembly 330 and toe weight assembly 331 are attached to body 302 via one or more windows 332, each positioned on a heel 320 side and a toe 322 side of golf club head 100. Heel weight assembly 330 and toe weight assembly 331 can be any configuration of weight system, including die-cast, co-molded, or embedded weight assemblies.

[0123] The heel weight assembly 330 and the toe weight assembly 331 include a weight 333 and one or more stainless steel fasteners 335. The material of the weight, washer, and fastener can be any metal, such as, but not limited to, tungsten, aluminum, titanium, steel, or stainless steel. This type of weight assembly is configured to be attached to and / or coupled to the golf club head body 302 before welding the striking face 304 to the body. The weight assembly can also be attached to or coupled to the golf club head body after welding the striking face to the body. This allows the weight 333 to be positioned within the internal cavity of the golf club head 300. This arrangement of the heel weight assembly 330 and the toe weight assembly 331 provides an alternative to overmolding while beneficially balancing the product of inertia and center of gravity characteristics, as described above.

[0124] 19-22, weight 333 of heel weight assembly 330 is approximately 22.3 grams. In other embodiments, the mass of weight 333 can be between 1 gram and 30 grams. In some embodiments, the mass of weight 333 can be 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, 7 grams, 8 grams, 9 grams, 10 grams, 11 grams, 12 grams, 13 grams, 14 grams, 15 grams, 16 grams, 17 grams, 18 grams, 19 grams, 20 grams, 21 grams, 22 grams, 23 grams, 24 grams, 25 grams, 26 grams, 27 grams, 28 grams, 29 grams, or 30 grams.

[0125] 19-22, the shape, geometry, and design of weight 333 are configured to be surrounded by a zone of products of inertia. The further the weight is from the center of gravity, the greater the magnitude of the products of inertia. Therefore, in this case, heel assembly 330 and toe assembly 331 are positioned extreme toward high toe 322 and low heel 320 to maximize the Ixy products of inertia while balancing (or nullifying) the Ixz terms of the products of inertia. Golf club head 300 is similar in dimensions to golf club head 100 and includes the same clock grid 2000 described in (FIG. 3). For example, FIGS. 19-21 show heel weight 333 having a block-like geometry, while FIGS. 19 and 22 show toe weight 333 having a plate-like geometry. To maximize the Ixy products of inertia, toe weight 333 can be positioned near toe 322 and crown 316 and at least partially enclosed between 11 o'clock line 2011 and 9 o'clock line 2009 of clock grid 2000 and intersect 10 o'clock line 2010. Additionally, heel weight 331 can be positioned near heel 320 and sole 318 and at least partially enclosed between 3 o'clock line 2003 and 5 o'clock line 2005 of clock grid 2000 and intersect 4 o'clock line 2004.

[0126] Heel weight 330 and toe weight 331 are configured to be mounted on a cast titanium body 302. If the material of the golf club head body 302 is changed, the shape, size, and geometry of the weights are reconfigured to precisely satisfy the product of inertia equations identified above. For example, as previously described, if the body 102 is made of a second composite material, heel weight 331 and toe weight 333 can be embedded (described below) or attached to the body 102.

[0127] The weight 333 of the toe weight assembly 331 as shown in Figures 19-22 is approximately 10.8 grams. In other embodiments, the mass of the weight 333 can be between 1 gram and 30 grams. In some embodiments, the mass of the weight 333 can be 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, 7 grams, 8 grams, 9 grams, 10 grams, 11 grams, 12 grams, 13 grams, 14 grams, 15 grams, 16 grams, 17 grams, 18 grams, 19 grams, 20 grams, 21 grams, 22 grams, 23 grams, 24 grams, 25 grams, 26 grams, 27 grams, 28 grams, 29 grams, and 30 grams. iv. Embedded weights

[0128] In some embodiments, the club head 100 can include one or more embedded weights 183 in combination with, or instead of, having one or more removable weights 182. In many embodiments, the one or more embedded weights 183 are permanently fixed to or within the club head 300. In some embodiments, the embedded weights 183 can be similar to the high density metal pieces (HDMPs) described in U.S. Provisional Patent Application No. 62 / 372,870, entitled "Embedded High Density Forging." In some embodiments, when the body 102 comprises a composite material, the one or more embedded weights 183 can be co-molded, overmolded, or attached to the body 102.

[0129] In many embodiments, one or more embedded weights 183 are positioned behind the striking face 104 of the club head 100 near the high toe 122 (closer to the crown 116 than the sole 118). In many embodiments, one or more embedded weights 183 are positioned near the rear 110 of the club head 100 near the low heel 120 (closer to the sole 118 than the crown 116). For example, in such an example, one or more weights 183 can be located near the toe 122 and the crown 116 and at least partially enclosed between the 11 o'clock line 2011 and the 9 o'clock line 2009 of the clock grid 2000 and intersect the 10 o'clock line 2010. Further, in one example, one or more weights 183 can be positioned near the heel 120 and sole 118 and can be at least partially enclosed between the 3 o'clock line 2003 and the 5 o'clock line 2005 of the clock grid 2000 and intersect the 4 o'clock line 2004.

[0130] In many embodiments, one or more embedded weights 183 are positioned within 0.10 inches, 0.20 inches, 0.30 inches, 0.40 inches, 0.50 inches, 0.60 inches, 0.70 inches, 0.80 inches, 0.90 inches, 1.0 inches, 1.1 inches, 1.2 inches, 1.3 inches, 1.4 inches, or 1.5 inches of the perimeter of the club head 300 when viewed from a top or bottom view (FIG. 3). In these embodiments, the proximity of the embedded weights 183 to the perimeter of the club head 100 may maximize a low and rearward head CG position, crown-sole moments of inertia Ixx, Ixy, and / or heel-toe moment of inertia Iyy.

[0131] In many embodiments, one or more embedded weights 183 can include a mass between 3.0 and 50 grams. For example, in some embodiments, one or more embedded weights 183 can include a mass between 3.0 and 25 grams, between 10 and 30 grams, between 20 and 40 grams, or between 30 and 50 grams. In embodiments in which one or more embedded weights 183 include two or more weights, each of the embedded weights can include the same or different masses.

[0132] In many embodiments, the one or more embedded weights 183 can include a material having a specific gravity between 6.0 and 22.0. For example, in many embodiments, the one or more embedded weights 183 can include a material having a specific gravity greater than 10.0, greater than 11.0, greater than 12.0, greater than 13.0, greater than 14.0, greater than 15.0, greater than 16.0, greater than 17.0, greater than 18.0, or greater than 19.0. In embodiments in which the one or more embedded weights 183 include two or more weights, each of the embedded weights can include the same or different materials. v. Steep crown angle

[0133] 4-6, in some embodiments, the golf club head 100 can further include a steep crown angle 188 to achieve a low, rearward position of the head CG. The steep crown angle 188 positions the back end of the crown 116 toward the sole 118 or ground, thereby lowering the club head CG position.

[0134] The crown angle 188 is measured as the acute angle between the crown axis 1090 and the front face 1020. In these embodiments, the crown axis 1090 lies within a cross-section of the club head taken along a plane disposed perpendicular to the ground plane 1030 and the front face 1020. The crown axis 1090 can be further described with reference to an upper transition boundary and a rear transition boundary.

[0135] Club head 100 includes an upper transition boundary between front end 108 and crown 116 that extends from near heel 120 to near toe 122. The upper transition boundary includes a crown transition profile 190 when viewed from a cross-sectional side view taken along a plane perpendicular to front surface 1020 and perpendicular to ground contact surface 1030 when club head 100 is in the address position. The cross-sectional side view can be taken at any point on club head 100 from near heel 120 to near toe 122. Crown transition profile 190 defines a front radius of curvature 192 that extends from front end 108 of club head 100 to crown transition point 194, where front end 108 of club head 100 is where the contour departs from the undulating and / or bulging range of striking face 104, and crown transition point 194 marks the change in curvature from front radius of curvature 192 to the curvature of crown 116. In some embodiments, the front radius of curvature 192 includes a single radius of curvature extending from an upper end 193 of the striking face perimeter 142 near the crown 116 to a crown transition point 194, where the upper end 193 of the striking face perimeter 142 near the crown 316 is where the contour deviates from the undulating and / or bulging range of the striking face 104, and the crown transition point 194 marks a change in curvature from the front radius of curvature 192 to one or more different curvatures of the crown 316.

[0136] Club head 100 further includes a rear transition boundary between crown 116 and skirt 128, extending from near heel 120 to near toe 122. The rear transition boundary includes a rear transition profile 196 when viewed from a cross-sectional side view taken along a plane perpendicular to front surface 1020 and perpendicular to ground contact surface 1030 when club head 100 is in the address position. The cross-sectional view can be taken at any point on club head 100 from near heel 120 to near toe 122. Rear transition profile 196 defines a back radius of curvature 198 that extends from crown 116 to skirt 128 of club head 100. In many embodiments, back radius of curvature 198 includes a single radius of curvature that transitions crown 116 to skirt 128 of club head 100 along the rear transition boundary. A first rear transition point 202 is located at the junction between crown 116 and rear transition boundary. The second rear transition point 203 is located at the junction between the rear transition boundary of the club head 100 and the skirt 128 .

[0137] The front radius of curvature 192 of the upper transition boundary may remain constant or may vary from near the heel 120 to near the toe 122 of the club head 100. Similarly, the back radius of curvature 198 of the rear transition boundary may remain constant or may vary from near the heel 120 to near the toe 122 of the club head 100.

[0138] A crown axis 1090 extends between a crown transition point 194 near the front end 108 of the club head 100 and a rear transition point 202 near the back end 110 of the club head 100. The crown angle 188 may remain constant or may vary from near the heel 120 to near the toe 122 of the club head 100. For example, the crown angle 188 may change when a cross-sectional side view is taken at different positions relative to the heel 120 and toe 122.

[0139] In the illustrated embodiment, the crown angle 188 near the toe 122 is approximately 72.25 degrees, the crown angle 188 near the heel 320 is approximately 64.5 degrees, and the crown angle 188 near the center of the golf club head is approximately 64.2 degrees. In many embodiments, the maximum crown angle 188 taken anywhere from near the toe 122 to near the heel 120 is less than 79 degrees, less than about 78 degrees, less than about 77 degrees, less than about 76 degrees, less than about 75 degrees, less than about 74 degrees, less than about 73 degrees, less than about 72 degrees, less than about 71 degrees, less than about 70 degrees, less than about 69 degrees, or less than about 68 degrees. For example, in some embodiments, the maximum crown angle is between 50 and 79 degrees, between 60 and 79 degrees, or between 70 and 79 degrees.

[0140] In other embodiments, the crown angle 188 near the toe 122 of the club head 100 can be less than about 79 degrees, less than about 78 degrees, less than about 77 degrees, less than about 76 degrees, less than about 75 degrees, less than about 74 degrees, less than about 73 degrees, less than about 72 degrees, less than about 71 degrees, less than about 70 degrees, less than about 69 degrees, or less than about 68 degrees. For example, the crown angle 188 taken along a cross-sectional side view positioned approximately 1.0 inch from the geometric center 140 of the striking face 104 toward the toe 122 can be less than 79 degrees, less than 78 degrees, less than 77 degrees, less than 76 degrees, less than 75 degrees, less than 74 degrees, less than 73 degrees, less than 72 degrees, less than 71 degrees, less than 70 degrees, less than 69 degrees, or less than 68 degrees.

[0141] Additionally, in other embodiments, the crown angle 188 near the heel 120 can be less than about 70 degrees, less than about 69 degrees, less than about 68 degrees, less than about 67 degrees, less than about 66 degrees, less than about 65 degrees, less than about 64 degrees, less than about 63 degrees, less than about 62 degrees, less than about 61 degrees, less than about 60 degrees, or less than about 59 degrees. For example, the crown angle 188 taken along a cross-sectional side view positioned approximately 1.0 inch from the geometric center 140 of the striking face 104 towards the heel 120 can be less than about 70 degrees, less than about 69 degrees, less than about 68 degrees, less than about 67 degrees, less than about 66 degrees, less than about 65 degrees, less than about 64 degrees, less than about 63 degrees, less than about 62 degrees, less than about 61 degrees, less than about 60 degrees, or less than about 59 degrees.

[0142] Additionally, in other embodiments, the crown angle 188 near the center of the club head 100 can be less than 75 degrees, less than 74 degrees, less than 73 degrees, less than 72 degrees, less than 71 degrees, less than about 70 degrees, less than about 69 degrees, less than about 68 degrees, less than about 67 degrees, less than about 66 degrees, less than about 65 degrees, less than about 64 degrees, less than about 63 degrees, less than about 62 degrees, less than about 61 degrees, less than about 60 degrees, or less than about 59 degrees. For example, the crown angle 188 taken along a cross-sectional side view located approximately at the geometric center 140 of the striking face 104 can be less than about 70 degrees, less than about 69 degrees, less than about 68 degrees, less than about 67 degrees, less than about 66 degrees, less than about 65 degrees, less than about 64 degrees, less than about 63 degrees, less than about 62 degrees, less than about 61 degrees, less than about 60 degrees, or less than about 59 degrees.

[0143] In many embodiments, reducing the crown angle 188 compared to current club heads creates a steeper crown or a crown that is positioned closer to the ground plane 1030 when the club head 100 is in the address position. Thus, reducing the crown angle 188 may result in a lower head CG position compared to club heads with higher crown angles. IV. Aerodynamic drag

[0144] In many embodiments, the club head 100 includes a combination of a low and rearward CG position of the club head, an increased moment of inertia of the club head, and high Ixy products of inertia, along with reduced aerodynamic drag.

[0145] In many embodiments, the club head 100 experiences an aerodynamic drag force of less than about 1.5 lbf, less than 1.4 lbf, less than 1.3 lbf, or less than 1.2 lbf when tested in a wind tunnel with a square face and a wind speed of 102 miles per hour (mph). In these or other embodiments, the club head 100 experiences an aerodynamic drag force of less than about 1.5 lbf, less than 1.4 lbf, less than 1.3 lbf, or less than 1.2 lbf when calculated using computational fluid dynamics with a square face and a wind speed of 102 miles per hour (mph). In these embodiments, the airflow experienced by the square-faced club head 100 is directed toward the striking face 104 in a direction perpendicular to the X'Y' plane. As described below, a club head 100 with reduced aerodynamic drag can be achieved using various means. i. Crown angle height

[0146] In some embodiments, decreasing the crown angle 188 to create a steeper crown and a lower head CG position can result in an undesirable increase in aerodynamic drag due to increased airflow separation over the crown during a swing. To prevent the increased drag associated with a decreased crown angle 188, the maximum crown height 204 can be increased. As shown in FIG. 4 , the maximum crown height 204 is the maximum distance between the surface of the crown 116 and the crown axis 1090 in any cross-sectional side view of the club head 100 along a plane parallel to the Y'Z' plane. In many embodiments, a greater maximum crown height 204 results in a crown 116 with a greater curvature. The greater the curvature of the crown 116, the further rearward the location of airflow separation during a swing moves. In other words, a greater curvature allows the airflow to remain in contact with the club head 100 for a longer distance along the crown 116 during a swing. Moving the airflow separation point rearward on the crown 116 can reduce aerodynamic drag and increase the club head swing speed, thereby increasing ball speed and distance.

[0147] In many embodiments, the maximum crown height 204 can be greater than about 0.20 inches (5 mm), greater than about 0.30 inches (7.5 mm), greater than about 0.40 inches (10 mm), greater than about 0.50 inches (12.5 mm), greater than about 0.60 inches (15 mm), greater than about 0.70 inches (17.5 mm), greater than about 0.80 inches (20 mm), greater than about 0.90 inches (22.5 mm), or greater than about 1.0 inches (25 mm). Additionally, in other embodiments, the maximum crown height can be within the range of 0.20 inches (5 mm) to 0.60 inches (15 mm), 0.40 inches (10 mm) to 0.80 inches (20 mm), or 0.60 inches (15 mm) to 1.0 inches (25 mm). For example, in some embodiments, the maximum crown height 404 can be about 0.52 inches (13.3 mm), about 0.54 inches (13.8 mm), about 0.59 inches (15 mm), about 0.65 inches (16.5 mm), or about 0.79 inches (20 mm). ii. Transition Profile

[0148] In many embodiments, the transition profile of the club head 100 from the striking face 104 to the crown 116, from the striking face 104 to the sole 118, and / or from the crown 116 to the sole 118 along the back end 110 of the club head 100 can affect the aerodynamic drag on the club head 100 during a swing.

[0149] In some embodiments, club head 100 having an upper transition boundary defining crown transition profile 190 and a rear transition boundary defining rear transition profile 196 further includes a sole transition boundary defining sole transition profile 210. The sole transition boundary extends between front end 108 and sole 118 from near heel 120 to near toe 122. The sole transition boundary includes sole transition profile 210 when viewed from a cross-sectional side view taken along a plane parallel to the Y'Z' plane. The cross-sectional side view can be taken at any point on club head 100 from near heel 120 to near toe 122. The sole transition profile 210 defines a sole radius of curvature 212 extending from the front end 108 of the club head 100 to a sole transition point 214, where the front end 108 of the club head 100 is where the contour deviates from the undulating and / or bulging range of the striking face 104, and the sole transition point 214 marks a change in curvature from the sole radius of curvature 212 to the curvature of the sole 118. In some embodiments, the sole radius of curvature 212 includes a single radius of curvature extending from a bottom end 213 of the striking face perimeter 142 near the sole 118 to the sole transition point 214, where the bottom end 113 of the striking face perimeter 142 near the sole 118 is where the contour deviates from the undulating and / or bulging range of the striking face 104, and the sole transition point 214 marks a change in curvature from the sole radius of curvature 212 to the curvature of the sole 214.

[0150] In many embodiments, the crown transition profile 190, the sole transition profile 210, and the rear transition profile 196 can be similar to the crown transition profile, the sole transition profile, and the rear transition profile described in U.S. Patent Application No. 15 / 233,486, entitled "Golf Club Head Having a Transition Profile for Reducing Aerodynamic Drag." Additionally, the front radius of curvature 192, the sole radius of curvature 212, and the back radius of curvature 198 can be similar to the first crown radius of curvature, the first sole radius of curvature, and the back radius of curvature described in U.S. Patent Application No. 15 / 233,486, entitled "Golf Club Head Having a Transition Profile for Reducing Aerodynamic Drag."

[0151] In some embodiments, the front radius of curvature 192 can be in the range of approximately 0.18 to 0.30 inches (0.46 to 0.76 cm). Additionally, in other embodiments, the front radius of curvature 192 can be less than 0.40 inches (1.02 cm), less than 0.375 inches (0.95 cm), less than 0.35 inches (0.89 cm), less than 0.325 inches (0.83 cm), or less than 0.30 inches (0.76 cm). For example, the front radius of curvature 192 can be approximately 0.18 inches (0.46 cm), 0.20 inches (0.51 cm), 0.22 inches (0.66 cm), 0.24 inches (0.61 cm), 0.26 inches (0.66 cm), 0.28 inches (0.71 cm), or 0.30 inches (0.76 cm).

[0152] In some embodiments, sole radius of curvature 212 can be in the range of approximately 0.25 to 0.50 inches (0.76 to 1.27 cm). For example, sole radius of curvature 212 can be less than approximately 0.5 inches (1.27 cm), less than approximately 0.475 inches (1.21 cm), less than approximately 0.45 inches (1.14 cm), less than approximately 0.425 inches (1.08 cm), or less than approximately 0.40 inches (1.02 cm). As a further example, sole radius of curvature 212 can be approximately 0.30 inches (0.76 cm), 0.35 inches (0.89 cm), 0.40 inches (1.02 cm), 0.45 inches (1.14 cm), or 0.50 inches (1.27 cm). In some embodiments, the back radius of curvature 198 can be in the range of about 0.10 to 0.25 inches (0.25 to 0.64 cm). For example, the back radius of curvature 198 can be less than about 0.30 inches (0.76 cm), less than about 0.275 inches (0.70 cm), less than about 0.25 inches (0.64 cm), less than about 0.225 inches (0.57 cm), or less than about 0.20 inches (0.51 cm). In further examples, the back radius of curvature 398 can be about 0.10 inches (0.25 cm), 0.15 inches (0.38 cm), 0.20 inches (0.51 cm), or 0.25 inches (0.64 cm). iii. Turbulator

[0153] 7 , in some embodiments, club head 100 can further include a plurality of turbulators 215, as described in U.S. Patent Application No. 13 / 536,753, now U.S. Patent No. 8,608,587, issued December 17, 2013, entitled “Turbulated Golf Club Head and Method of Manufacturing a Turbulated Golf Club Head,” the contents of which are incorporated herein by reference in their entirety. In many embodiments, the plurality of turbulators 215 disrupts the airflow, thereby creating small vortices or turbulence within the boundary layer, imparting energy to the boundary layer and delaying separation of the airflow over crown 116 during a swing.

[0154] In some embodiments, the plurality of turbulators 215 can be adjacent to the crown transition point 194 of the club head 100. The plurality of turbulators 215 protrude from the outer surface of the crown 116 and include a length extending between the front end 108 and the back end 110 of the club head 100 and a width extending from the heel 120 to the toe 122 of the club head 100. In many embodiments, the length of the plurality of turbulators 215 is greater than the width. In some embodiments, the plurality of turbulators 215 can include the same width. In some embodiments, the plurality of turbulators 215 can have a varying height profile. In some embodiments, the plurality of turbulators 215 can be taller toward the apex of the crown 116 compared to the front of the crown 116. In other embodiments, the plurality of turbulators 215 can be taller toward the front of the crown 116 and shorter in height toward the apex of the crown 116. In other embodiments, the plurality of turbulators 215 can include a constant height profile. Additionally, in many embodiments, at least a portion of at least one turbulator is disposed between the striking face 104 and the apex of the crown 116, and the spacing between adjacent turbulators is greater than the respective widths of the adjacent turbulators. V. Products of inertia, moments of inertia, CG position, and resistance balance

[0155] The golf clubs described below use several relationships that balance the club head's moments of inertia and products of inertia relative to a lower, rearward CG position while maintaining or reducing aerodynamic drag. Balancing these relationships between CG, moments of inertia, products of inertia, and drag improves impact performance characteristics (e.g., prevention of side spin on high and low face hits, launch angle, ball speed, and forgiveness) and swing performance characteristics (e.g., aerodynamic drag, ability to square the club head at impact, swing speed). This balance is applicable to driver-type club heads 100. a. Balance of product of inertia (Ixy ratio) and CG height

[0156] The Ixy ratio (Equation 5 below) represents the symmetry of the club head 100 about the x-axis 1050 relative to the symmetry of the club head 100 about the y-axis 1060. The Ixy ratio is the α multiplied by the torque z and hence the resulting angular acceleration (α y ) The greater the Ixy ratio, the greater the influence the club has on the rotational velocity of the club head 100 about the x and y axes, resulting in more consistent impact characteristics (i.e., forgiveness when hitting an off-center ball) because the golf club head 100 rotates to counteract side spin that results from differences between the face angle and the club head path.

number

[0157] In current golf club head designs, increasing the Ixy products of inertia of a golf club head 100 can adversely affect other performance characteristics of the club head 100, such as CG height 174 (the distance of the CG from the midplane of the golf club head). The club head 100 described herein increases or maximizes the Ixy products of inertia of the club head while maintaining or decreasing CG height 174. Thus, a club head 100 with improved impact performance characteristics (e.g., spin, forgiveness, launch) also balances or improves swing performance characteristics (e.g., aerodynamic drag, ability to square the club at impact).

[0158] The optimal locations for placing discretionary mass to increase Ixy are in the high toe region (between the 11 o'clock line and the 9 o'clock line) and the low heel region (between the 3 o'clock line and the 5 o'clock line) of the golf club head 100. However, it is a factor known in the art that the lower the CG height 174 (closer to the sole), the better / more optimal the golf ball launch at impact. The optimal locations for discretionary mass placement to increase Ixy conflict with the optimal placement of discretionary mass to lower the CG height 174 of the golf club head.

[0159] 15, for many known club heads, CG height increases as Ixy increases. The club head 100 described herein increases or maximizes Ixy compared to known club heads of similar volume and / or loft angle while maintaining a desirable CG height 174. Thus, the club head 100, which provides improved impact performance characteristics (e.g., spin, forgiveness, launch), also balances and / or improves swing performance characteristics (e.g., aerodynamic drag, ability to square the club at impact).

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[0160] The Ixz ratio (Equation 6 below) represents the symmetry of the club head 100 about the x-axis 1050 relative to the symmetry of the club head 100 about the z-axis 1070. The Ixz ratio is the α multiplied by the torque z and hence the resulting angular acceleration about the z-axis 1070 (α z ) to produce a balanced golf club head. The optimum magnitude of Ixz is zero. However, if zero cannot be achieved, it is preferable that Ixz be as close to zero as possible without becoming positive in magnitude.

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[0161] In current golf club head designs, balancing the Ixz products of inertia of a golf club head (driving the magnitude of the Ixz products of inertia to zero) can adversely affect other performance characteristics of the club head, such as CG depth 172 (the distance of the CG from the loft plane of the golf club head). The club head 100 described herein balances or drives the Ixz products of inertia of the club head 100 to zero while maintaining a desirable CG depth 172. Thus, a club head 100 with improved impact performance characteristics (e.g., spin, forgiveness, launch) also balances or improves swing performance characteristics (e.g., aerodynamic drag, ability to square the club at impact).

[0162] The optimal locations for placing discretionary mass to balance (or nullify) Ixz are in the high-toe and low-heel regions of golf club head 100. However, it is a factor known in the art that the deeper the CG depth 172 (toward the rear perimeter of the club, farther from the strike loft plane), the better / more optimal the golf ball launch at impact. The optimal location of discretionary mass to balance Ixz conflicts with the optimal location of discretionary mass to increase the CG depth 172 of golf club head 100.

[0163] 17 , for many known club heads, CG depth 172 decreases as Ixz approaches zero. Club head 100 described herein balances or zeros the Ixz product of inertia compared to known club heads of similar volume and / or loft angle while maintaining a desirable CG depth 172. Thus, club head 100 with improved impact performance characteristics (e.g., spin, forgiveness, launch) also balances and / or improves swing performance characteristics (e.g., aerodynamic drag, ability to square the club at impact).

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[0164] In many known golf club heads, shifting the CG location further rearward to increase the golf ball launch angle and / or increase the club head's moment of inertia can adversely affect other performance characteristics of the club head, such as aerodynamic drag and products of inertia. Figure 16 shows that for many known club heads having similar volume and / or loft angles as the club head, as the club head CG depth 172 increases (to increase the club head's forgiveness and / or launch angle), drag forces during a swing increase (thereby decreasing swing speed and ball distance). For many known club heads, as the head CG depth increases, drag forces on the club head increase and Ixy decreases.

[0165] The club head 100 described herein balances the club head's CG depth 172 and Ixy products of inertia compared to known club heads of similar volume and / or loft angle while maintaining or reducing aerodynamic drag. Thus, club head 100 with improved impact performance characteristics (e.g., spin, launch angle, ball speed, and forgiveness) also balances or improves swing performance characteristics (e.g., aerodynamic drag, ability to square the club head at impact, and swing speed).

[0166] In many embodiments, the club head 100 provides a resistance force (F d The following relationship is satisfied so as to increase the Ixy inertia product ratio of the head while maintaining or decreasing the Ixy inertia product ratio.

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[0167] In many known golf club heads, shifting the CG location further rearward to increase the golf ball launch angle and / or increase the club head's moment of inertia can adversely affect other performance characteristics of the club head, such as aerodynamic drag and products of inertia. Figure 18 shows that for many known club heads with similar volume and / or loft angles as the club head, as the club head's CG depth increases (to increase the club head's forgiveness and / or launch angle), the drag forces during swing increase (thereby decreasing swing speed and ball distance). For many known club heads, as head CG depth increases, the drag forces on the club head increase and Ixz decreases (becomes more negative in magnitude).

[0168] The club heads described herein increase or maximize the CG depth and Ixz products of inertia of the club head compared to known club heads of similar volume and / or loft angle while maintaining or reducing aerodynamic drag. Thus, club heads with improved impact performance characteristics (e.g., spin, launch angle, ball speed, and forgiveness) also balance or improve swing performance characteristics (e.g., aerodynamic drag, ability to square the club head at impact, and swing speed).

[0169] In many embodiments, the club head provides a resistance force (F d The following relationship is satisfied so that the Ixz product of inertia ratio of the head is balanced while maintaining or reducing the Ixz product of inertia ratio.

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[0170] Described herein is an exemplary golf club head having similar dimensions (length, width, height, depth, CG height, CG depth) as golf club head 100 and similar weight location to club head 300. The exemplary golf club head has a volume of 466 cc, a depth of 4.81 inches, a length of 5.10 inches, and a height of 2.57 inches. The exemplary club head includes multiple thinned regions (similar to those in golf club head 100) on the crown that comprise 57% of the crown surface area and have a minimum thickness of 0.013 inches. The exemplary club head further includes a crown angle of 68.6 degrees (similar to that in golf club head 100) and a crown angle height of 0.522 inches.

[0171] The exemplary club head includes two embedded weights comprising tungsten with a specific gravity of 14SG and masses of 16.6 grams and 22.8 grams. One embedded weight is located near the toe and crown and is at least partially enclosed between the 11 o'clock line and the 9 o'clock line of a clock grid (the clock grid is the same as that of club head 100) and intersects the 10 o'clock line (similar to that of club head 300). Additionally, a second embedded weight is located near the heel and sole and is at least partially enclosed between the 3 o'clock line and the 5 o'clock line of the clock grid and intersects the 4 o'clock line. In this example, the club head is structured to form an inertia tensor matrix as follows:

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[0172] As a result of the above and / or additional parameters, the exemplary club head includes a head CG depth of 1.36 inches and a head CG height of 0.14 inches. Further, as a result of the above and / or additional parameters, the exemplary club head includes a head CG depth of 2,684 g·cm 2 Crown-sole moment of inertia Ixx: 4,684 g cm 2 Heel-toe moment of inertia Iyy, 164g cm 2 Ixy product of inertia, -154g cm 2 Ixz product of inertia, and 7,368 g cm 2 This includes the resultant moment of inertia Ixx+Iyy.

[0173] The exemplary club head further includes a front radius of curvature of 0.24 inches (similar to golf club head 100), a sole radius of curvature of 0.30 inches, and a back radius of curvature of 0.20 inches. As a result of these and / or additional parameters, the exemplary club head includes an aerodynamic drag force of 0.95 lbf calculated by computational fluid dynamics for a square surface and a wind speed of 102 miles per hour (mph).

[0174] The exemplary club head was compared to a control golf club (hereinafter "control club") of similar height, length, and volume. However, the control club had only one weight on the rear outer perimeter of the club head. Additionally, the control club included an inertia tensor matrix as follows:

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[0175] The exemplary club head exhibits a 27.5% reduction in Ixx and a 6% reduction in Iyy compared to the control club. The exemplary club head exhibits a 27% reduction in CG depth and a 68% reduction in CG height compared to the control club. However, the exemplary club head exhibits an 18.4% increase in Izz, a 49.7% increase in Ixy, and a 73% increase in Ixz compared to the control club.

[0176] Referring to Figure 23, the side spin introduced by high and low face hits is plotted for the control club and the exemplary club. The horizontal axis of Figure 23 represents the impact height on the striking face, where the origin is the geometric center, negative values ​​are below center, and positive values ​​are above center. The vertical axis of Figure 23 represents the side spin (in revolutions per minute) imparted to the golf ball at impact, where positive values ​​are fade spin and negative values ​​are draw spin.

[0177] Referring to Figure 23, the exemplary club nearly eliminates all unwanted side spin when hitting the golf ball between 0.1 inches and 1 inch below center. More specifically, when hitting the golf ball 0.6 inches below the geometric center, the exemplary club head reduces side spin by approximately 125 RPM relative to the control club. When hitting the golf ball 0.4 inches below center, the exemplary club reduces side spin by approximately 75 RPM.

[0178] 23, striking the golf ball above-center results in an equally significant reduction in unwanted side spin. However, the control club's high fade spin (about 50 RPM to about 150 RPM) is transitioned to very little draw spin (about 0 RPM to about 45 RPM). It can be concluded that the exemplary club head, despite having reduced Ixx and Iyy compared to the control club, reduces or even eliminates unwanted side spin when striking the golf ball above or below-center. This reduction (or elimination) of side spin for the exemplary club head provides greater forgiveness than the control club's high Ixx term because the ball flies on a straighter trajectory rather than spinning off-line.

[0179] Furthermore, the exemplary club head only reduces the Iyy term by 6.8%, thereby still maintaining optimal forgiveness when the golf ball is struck toward the toe or toward the heel. The Iyy moment of inertia is often maximized as much as possible, as is evident from the control club. However, the small reduction in Iyy and the significant increases in the Ixz and Ixy terms cause the exemplary club head to become more forgiving in all four directions (toward the toe, heel, crown, and sole) away from the geometric center, rather than simply toward the heel and toe as with the control club.

[0180] The exemplary club head balances increased forgiveness (achieved through a balanced MOI and product of inertia) against a deep, low CG, enabling desirable launch conditions. A high launch and low spin ball flight is desired with a driver-type club head to hit high, long-flying golf shots. When the exemplary club head's CG height and CG depth are paired with an inertia tensor (achieved through embedded weights similar to that of golf club head 300), a high launch, low spin, and straighter (with increased forgiveness to balance the product of inertia against the MOI) driver is created.

[0181] Finally, note that the exemplary club balances the inertia tensor and CG parameters while maintaining steep front, sole, and back radii of curvature. As a result of these and / or additional parameters, the exemplary club head includes an aerodynamic drag force of 0.95 lbf, which is equal to that of the control club head. However, as previously mentioned, the exemplary club head has a more favorable balance of increased forgiveness and desirable performance characteristics (high launch and low spin due to CG height and CG depth) while maintaining swing speed (due to lower drag forces).

[0182] The substitution of one or more claimed elements constitutes a rearrangement, not a repair. Furthermore, benefits, other advantages, and solutions to problems have been described with respect to particular embodiments. However, the benefits, advantages, solutions to problems, and any elements that may give rise to or make more apparent any benefits, advantages, or solutions should not be construed as key, necessary, or essential features or elements of such claims.

[0183] The Rules of Golf may change from time to time (e.g., new Rules may be adopted, or old Rules may be repealed or modified, by golf's standards bodies and / or governing bodies such as the United States Golf Association (USGA) or the Royal and American Golf Association (R&A)), and golf equipment relating to the devices, methods, and / or articles of manufacture disclosed herein may or may not conform to the Rules of Golf at any given time. Accordingly, golf equipment relating to the devices, methods, and / or articles of manufacture disclosed herein may be advertised, offered for sale, and / or sold as conforming or not conforming to golf equipment. The devices, methods, and / or articles of manufacture disclosed herein are not limited in this respect.

[0184] Although the above embodiments may be described in the context of wood-type golf clubs (e.g., drivers, fairway woods), the devices, methods, and articles of manufacture described herein may also be applied to other types of golf clubs, such as hybrid-type golf clubs, iron-type golf clubs, wedge-type golf clubs, or putter-type golf clubs. Alternatively, the devices, methods, and articles of manufacture described herein may also be applied to other types of sports equipment, such as hockey sticks, tennis rackets, fishing rods, ski poles, etc.

[0185] Furthermore, embodiments and limitations disclosed herein are not available to the public under the doctrine of public domain if the embodiment and / or limitation (1) is not explicitly claimed in the claims and (2) is a potential equivalent of an explicit element and / or limitation of the claims under the doctrine of equivalents.

[0186] Various features and advantages of the disclosure are set forth in the following claims.

Claims

1. A hollow golf club head, a body having a front end, a back end opposite the front end, a crown, a sole opposite the crown, a heel, a toe opposite the heel, a skirt adjacent the crown and the sole, and a hosel structure having a hosel axis extending centrally through a bore of the hosel structure; a striking surface disposed at the front end, the striking surface defining a geometric center, a loft plane tangent to the geometric center, and a head depth plane extending from the heel to the toe, through the geometric center, and perpendicular to the loft plane; The loft angle of the club head is less than 16 degrees; The volume of the club head is greater than 400 cc, a center of gravity of the club head is located at a position of a head CG depth from the loft plane measured in a direction perpendicular to the loft plane, and at a position of a head CG height from the head depth plane measured in a direction perpendicular to the head depth plane; the head CG height is less than 0.20 inches; a y-axis extends through the center of gravity of the head from the crown toward the sole, an x-axis extending from the heel to the toe through the center of gravity of the head; the x-axis is perpendicular to the y-axis; the club head experiences a resistance force Fd when subjected to a wind speed of 102 mph in a direction passing through the geometric center of the striking face, extending parallel to the hosel axis, and perpendicular to a plane positioned at the loft angle from the loft plane; the club head has a crown-sole moment of inertia Iyy, a heel-toe moment of inertia Ixx, and a product of inertia Ixy about the x-axis and the y-axis; The product of inertia is 100 g cm ２ is larger than The golf club head satisfies relationship A and relationship B. [Equation 1] [Equation 2]

2. The golf club head of claim 1 , wherein the club head further satisfies relationship C. [Equation 3]

3. The golf club head of claim 1 , wherein the club head further satisfies relationship D. [Equation 4]

4. The golf club head of claim 1 , wherein the head CG depth is greater than 1.3 inches.

5. The club head further comprises: It has a line at the 12 o'clock position, a line at the 3 o'clock position, a line at the 4 o'clock position, a line at the 5 o'clock position, a line at the 8 o'clock position, a line at the 9 o'clock position, a line at the 10 o'clock position, and a line at the 11 o'clock position, the 12 o'clock line is aligned with a center point of the striking face in a bottom view of the club head when the club head is in an address position and is perpendicular to a front intersection line between the loft plane and the ground plane; the clock grid is aligned along the 12 o'clock line at a midpoint between a front end of the head and a rear end of the head; the three o'clock line extends toward a heel portion of the head; the 9 o'clock line extends toward a toe portion of the head, The club head further comprises: The device includes a first embedded weight and a second embedded weight, the first embedded weight may be disposed near the toe and the crown, at least partially enclosed between the 11 o'clock line and the 9 o'clock line of the clock grid, and intersect the 10 o'clock line; 2. The golf club head of claim 1, wherein the second embedded weight is positioned near the heel and the sole, is at least partially enclosed between the 3 o'clock line and the 5 o'clock line of the clock grid, and can intersect the 4 o'clock line.

6. The moment of inertia Iyy is 4500 g cm ２ The golf club head of claim 1 , wherein

7. The golf club head of claim 5 , wherein the first embedded weight and the second embedded weight comprise tungsten.

8. The composite moment of inertia is 7250 g cm ２ The golf club head of claim 1 , wherein the axial length is greater than 1 / 2.

9. The golf club head of claim 1 further comprises: a front radius of curvature between 0.18 inches and 0.30 inches, the front radius of curvature extending from an upper edge of the striking face to a crown transition point, the crown transition point marking a transition from the front radius of curvature to a different curvature of the crown; 2. The golf club head of claim 1, further comprising: a first rear transition point located at the junction between the crown and the rear transition boundary; and a back radius of curvature extending from a second rear transition point located at the junction between the rear transition boundary and the skirt along the rear transition boundary between the crown and the skirt of the golf club head.

10. The golf club head further comprises: a crown angle of less than 79 degrees, the crown angle being measured as the acute angle between a front surface and a crown axis extending through the crown transition point and the rear transition point of the golf club head; 10. The golf club head of claim 9, comprising a maximum crown height greater than 0.50 inches, the maximum crown height measured as the maximum distance between the surface of the crown and the crown axis.

11. A hollow golf club head, a body having a front end, a back end opposite the front end, a crown, a sole opposite the crown, a heel, a toe opposite the heel, a skirt adjacent the crown and the sole, and a hosel structure having a hosel axis extending centrally through a bore of the hosel structure; a striking surface disposed at the front end, the striking surface defining a geometric center, a loft plane tangent to the geometric center, and a head depth plane extending from the heel to the toe, through the geometric center, and perpendicular to the loft plane; The loft angle of the club head is less than 16 degrees; The volume of the club head is greater than 400 cc, a center of gravity of the club head is located at a position of a head CG depth from the loft plane measured in a direction perpendicular to the loft plane, and at a position of a head CG height from the head depth plane measured in a direction perpendicular to the head depth plane; the head CG height is less than 0.20 inches; a y-axis extends through the center of gravity of the head from the crown toward the sole, an x-axis extending from the heel to the toe through the center of gravity of the head; the x-axis is perpendicular to the y-axis; the club head experiences a resistance force Fd when subjected to a wind speed of 102 mph in a direction passing through the geometric center of the striking face, extending parallel to the hosel axis, and perpendicular to a plane positioned at the loft angle from the loft plane; the club head has a crown-sole moment of inertia Iyy, a heel-toe moment of inertia Ixx, and a product of inertia Ixy about the x-axis and the y-axis; The product of inertia is 100 g cm ２ is larger than the club head has a striking face-to-skirt moment of inertia Izz, a heel-toe moment of inertia Ixx, and a product of inertia Ixz about the z-axis and the x-axis; A golf club head, wherein the club head satisfies relationship A. [Equation 5]

12. The golf club head of claim 11 , wherein the club head further satisfies relationship B. [Equation 6]

13. The golf club head of claim 11 , wherein the club head further satisfies relationship C. [Equation 7]

14. The golf club head of claim 11 , wherein the club head further satisfies relationship D. [Equation 8]

15. The golf club head of claim 11 , wherein the head CG depth is greater than 1.3 inches.

16. The club head further comprises: It has a line at the 12 o'clock position, a line at the 3 o'clock position, a line at the 4 o'clock position, a line at the 5 o'clock position, a line at the 8 o'clock position, a line at the 9 o'clock position, a line at the 10 o'clock position, and a line at the 11 o'clock position, the 12 o'clock line is aligned with a center point of the striking face in a bottom view of the club head when the club head is in an address position and is perpendicular to a front intersection line between the loft plane and the ground plane; the clock grid is aligned along the 12 o'clock line at a midpoint between a front end of the head and a rear end of the head; the three o'clock line extends toward a heel portion of the head; the 9 o'clock line extends toward a toe portion of the head, The club head further comprises: The device includes a first embedded weight and a second embedded weight, the first embedded weight may be disposed near the toe and the crown, at least partially enclosed between the 11 o'clock line and the 9 o'clock line of the clock grid, and intersect the 10 o'clock line; 12. The golf club head of claim 11, wherein the second embedded weight is positioned near the heel and the sole, and is at least partially enclosed between the 3 o'clock line and the 5 o'clock line of the clock grid and can intersect the 4 o'clock line.

17. The golf club head of claim 16 , wherein the first embedded weight and the second embedded weight comprise tungsten.

18. The combined moment of inertia is 7250 g cm ２ The golf club head of claim 11 , wherein

19. The golf club head further comprises: -160 g cm ２ The golf club head of claim 11 , wherein the product of inertia Ixz is greater than

20. The moment of inertia Iyy is 4500 g cm ２ The golf club head of claim 11 , wherein

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