Golf club head having an optimized moment of inertia

Abstract

A driver-type golf club head having a body shape like a cube, wherein the ratio of the body height to the body depth is between 0.5 and 0.75, and the ratio of the body height to the body width is between 0.5 and 0.75. The golf club head further comprises a mass distribution in which most of the club head mass is located within a central mass zone centered on the Y' axis. The golf club head further comprises moments of inertia Ixx and Iyy, and the Ixx / Iyy ratio is greater than 0.8. In many embodiments, the golf club head further comprises optimized bulge and roll curvatures determined by Ixx, Iyy, CG position, coefficient of restitution, and / or other characteristics.

Description

Technical Field

[0001] (Cross-reference regarding priority) This claims the benefit of priority of U.S. Provisional Application No. 63 / 503,134, filed May 18, 2023; U.S. Provisional Application No. 63 / 370,482, filed Aug. 4, 2022; and U.S. Provisional Application No. 63 / 368,626, filed Jul. 15, 2022, all of which are incorporated herein by reference in their entirety.

[0002] The present disclosure generally relates to golf equipment, and more particularly to golf heads. In particular, the present invention relates to golf club heads having an optimized moment of inertia and / or an optimized bulge curvature and roll curvature.

Background Art

[0003] Historically, the design of golf club heads, particularly wood-type golf club heads, has tended to increase the moment of inertia of the club head to provide more forgiveness and minimize the reduction in ball speed for mishits. Most commonly, prior art club head designs are adapted in a direction to increase the moment of inertia Iyy (i.e., the moment of inertia about the Y-axis that extends vertically through the center of gravity of the club head), as Iyy mainly contributes to the performance and forgiveness of the club head, particularly in shots mishit towards the heel or toe. Such club heads are designed to achieve the highest possible Iyy. Prior art club head designs attempting to maximize Iyy often include a flat body profile with a large amount of peripheral weighting that places discretionary mass away from the Y-axis. However, in maximizing Iyy, prior art club head designs can often neglect the moment of inertia Ixx (i.e., the moment of inertia about the X-axis that extends through the center of gravity of the club head), or other characteristics such as bulge curvature and roll curvature. Excessively low Ixx and / or bulge curvature or roll curvature that is not optimized for a given club head can reduce forgiveness and carry distance on mishits, even if Iyy is high.

[0004] In some cases, it may be desirable to provide a wood-type club head that achieves a specific Iyy target. In many cases, an Iyy target that is lower than that of a typical prior art club head may be desirable. In some cases, a low Iyy target may be desirable to fit the club head to a specific player or subset of players. However, designing a club head with a low Iyy target can potentially have an adverse effect on the forgiveness and performance of the club head, as Iyy is an important factor for both. There is a need in the art to maximize the performance of a club head with respect to achieving a target Iyy. In particular, there is a need in the art to maximize said performance by balancing Ixx, Iyy, CG position, and the bulge and roll curvatures, with respect to a club head that achieves a target Iyy lower than that of a typical prior art club head.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0033] Other aspects of the present disclosure will become apparent by considering the detailed description and the accompanying drawings.

[0034] For simplicity and clarity of illustration, the drawings exemplify the general aspects of the structure, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the present disclosure. Further, the elements in the drawings are not necessarily drawn to scale. For example, the dimensions of some elements in the figures may be exaggerated relative to other elements to improve the understanding of the embodiments of the present disclosure. The same reference numerals across different figures indicate the same elements.

[0035] The terms "first", "second", "third", "fourth", etc. in this specification and the claims are used, if at all, to distinguish similar elements and are not necessarily used to describe a particular order or chronological sequence. It should be understood that terms used in this way are interchangeable in appropriate circumstances such that the embodiments described herein can operate in an order other than that illustrated or otherwise described herein. Further, the terms "include", "have", and their variations are intended to cover non-exclusive inclusion such that a process, method, system, article, device, or apparatus that comprises a list of elements is not necessarily limited to those elements, may include other elements not expressly listed or inherent to such process, method, system, article, device, or apparatus.

[0036] The terms "left", "right", "front", "rear", "up", "down", "upper", "lower", etc. in this specification and the claims are used for purposes of explanation and are not necessarily used to describe a permanent relative position. It should be understood that terms used in this way are interchangeable in appropriate circumstances such that the embodiments of the invention described herein can operate in an orientation other than that illustrated or otherwise described herein.

[0037] The terms "couple", "coupled", "couples", "coupling", etc. are to be understood broadly and refer to connecting two or more elements or signals electrically, mechanically, and / or otherwise.

[0038] Various embodiments of a golf club are shown in the figures. A golf club is generally understood to comprise a club head configured to receive a shaft. The golf club further comprises a grip fixed to the shaft.

[0039] Figures 1 to 6 schematically show various embodiments of a driver-type golf club head in various figures. The features discussed below are shown on club head 100. For ease of discussion, the features shown on club head 100 are applicable to various embodiments of the club head according to the present invention. Any one or more of the features described in the various embodiments below can be used in combination with each other. Further, while different embodiments have different numbering schemes (i.e., numbering schemes such as 1xx, 2xx, 3xx, etc.), similar elements are numbered similarly between embodiments (i.e., club head 100 includes a crown 110 and a sole 112, while club head 200 includes a crown 210 and a sole 212).

[0040] Club head 100 can include a striking face 102 and a body 101 fixedly joined together to define a substantially closed / hollow internal cavity. Club head 100 includes a crown 110, a sole 112 opposite the crown 110, a heel 104, a toe 106 opposite the heel 104, a front end 108, and a rear end 111 opposite the front end 108. Body 101 is located between crown 110 and sole 112 and can further include a skirt 114 and / or a trailing edge 109 adjacent to crown 110. Skirt 114 can extend from near heel 104 of club head 100 to near toe 106.

[0041] The club head 100 can comprise one or more body materials such as steel, stainless steel, tungsten, aluminum, titanium, vanadium, chromium, cobalt, nickel, other metals, or metal alloys. In some embodiments, the body material can comprise a Ti-8Al-1Mo-1V alloy, or 17-4 stainless steel. In some embodiments, the body material can be formed from C300, C350, Ni (nickel)-Co (cobalt)-Cr (chromium)-steel alloy, 565 steel, AISI type 304 or AISI type 630 stainless steel, 17-4 stainless steel, titanium alloys such as, for example, Ti-6-4, Ti-3-8-6-4-4, Ti-10-2-3, Ti15-3-3-3, Ti15-5-3, Ti185, Ti6-6-2, Ti-7s, Ti-9s, Ti-92, or Ti-8-1-1 titanium alloy, amorphous metal alloy, or other similar metals, but is not limited thereto. In some embodiments, one or more portions of the club head 100 can comprise a non-metallic material.

[0042] As used herein, "ground plane" refers to a reference plane associated with the surface on which a golf ball is placed. The ground plane 1010 can be a horizontal plane that is tangent to the sole at the address position. The address position is defined in more detail below. The ground plane 1010 is illustrated in FIG. 2.

[0043] As used herein, "loft plane" refers to a reference plane that is tangent to the geometric center of the striking face (the "geometric center" will be described later). The loft plane 1015 is shown in FIG. 3.

[0044] As used herein, the term "loft angle" can refer to the angle measured between the loft plane 1015 and the XY plane (defined below). The loft angle 10 is illustrated in FIG. 3.

[0045] As used herein, the term "lie angle" can refer to the angle between the hosel axis 1020 extending through the hosel 105 and the ground plane. The lie angle 15 is measured from the front view of the club head as shown in FIG. 2.

[0046] The club head 100 can define an "address position" (also referred to as "address"), where the club head is oriented such that it forms its intended loft angle 10 and lie angle 15. For example, at the address position, the loft face 1015 and the XY plane form the intended loft angle 10 between each other. Similarly, at the address position, the hosel axis 1020 and the ground plane 1010 form the intended lie angle 15 between each other.

[0047] As shown in FIGS. 2 and 3, the club head 100 can define a primary coordinate system centered on the geometric center 120 of the striking face 102. The primary coordinate system can include an X-axis 1040, a Y-axis 1050, and a Z-axis 1060. The X-axis 1040 can extend in the toe-to-heel direction, parallel to the ground plane 1010. The X-axis 1040 can be positive towards the heel 104 and negative towards the toe 106. The Y-axis 1050 can extend from the crown to the sole direction and can be orthogonal to both the ground plane 1010 and the X-axis 1040. The Y-axis 1050 can be positive towards the crown 110 and negative towards the sole 112. The Z-axis 1060 can extend in the front-to-back direction, parallel to the ground plane 1010, and can be orthogonal to both the X-axis 1040 and the Y-axis 1050. The Z-axis 1060 can be positive towards the striking face 102 and negative towards the rear end 108.

[0048] As described herein, the primary coordinate system defines the XY plane as a vertical plane extending along the X-axis 1040 and the Y-axis 1050. The primary coordinate system defines the XZ plane as a horizontal plane extending along the X-axis 1040 and the Z-axis 1060. The primary coordinate system further defines the YZ plane as a vertical plane extending along the Y-axis 1050 and the Z-axis 1060. The XY plane, the XZ plane, and the YZ plane are all perpendicular to each other and intersect at the origin of the primary coordinate system located at the geometric center 120 of the striking face 102. In these or other embodiments, the clubhead 100 can be viewed from the front when the striking face 102 is viewed from a direction perpendicular to the XY plane. Further, in these or other embodiments, the clubhead 100 can be viewed from a side view or a side cross-sectional view when the heel 104 or the toe 106 is viewed from a direction perpendicular to the YZ plane.

[0049] As used herein, the "body depth" or "depth" D of the clubhead 100 B refers to the dimension from front to back measured across the body 101. Referring to FIGS. 3 and 4, the body depth D B is measured parallel to the Z-axis 1060 from the leading edge 103 to the rearmost point 117 of the body 101.

[0050] As used herein, the "body height" or "height" H of the clubhead 100 B can refer to the dimension from the crown to the sole measured across the body 101. Referring to FIG. 2, the body height H B can be measured as the vertical distance (parallel to the Y-axis 1050) between the ground plane 1010 and the highest point of the crown 110. In many embodiments, the body height H B can be measured in accordance with a golf governing body such as the United States Golf Association (USGA).

[0051] As used herein, the "body width" or "width" W of the clubhead 100 B can refer to the dimension from the heel to the toe measured across the body 101. Referring to FIG. 2, the body width W Bcan be measured parallel to the X-axis 1040 from the heel apex 116 to the toe apex 119. The toe apex 119 is defined as the most toe-side point of the body 101. The heel apex 116 is the most heel-side point of the heel 104 located at a height of 0.875 mm from the ground contact surface 1010. In many embodiments, the body width W B can be measured according to a golf governing body such as the United States Golf Association (USGA). The body depth D B , the body height H B , and the body width W B The specified ranges for can be designed according to the USGA rules.

[0052] The "center of gravity" or "CG" of the clubhead described in this specification can refer to the point where the mass is at the center within the clubhead. CG160 is shown in FIGS. 2 and 3.

[0053] The term or phrase "center of gravity position" or "CG position" can refer to the position of the center of gravity (CG) of the clubhead with respect to a primary coordinate system, and the CG position is characterized by the positions along the X-axis 1040, Y-axis 1050, and Z-axis 1060. The term "CGx" can refer to the CG position along the X-axis 1040, measured from the geometric center 120. The term "CG height" can refer to the CG position along the Y-axis 1050, measured from the geometric center 120. The term "CGy" can be synonymous with the CG height. The term "CG depth" can refer to the CG position along the Z-axis 1060, measured from the geometric center 120. The term "CGz" can be synonymous with the CG depth.

[0054] The golf club head further comprises a secondary coordinate system centered on the center of gravity 160. As shown in FIGS. 2 and 3, the secondary coordinate system includes an X'-axis 1070, a Y'-axis 1080, and a Z'-axis 1090. The X'-axis 1070 extends in the direction from the heel to the toe. The X'-axis 1070 is positive toward the heel 104 and negative toward the toe 106. The Y'-axis 1080 extends in the direction from the sole to the crown, and is orthogonal to both the Z'-axis 1090 and the X'-axis 1070. The Y'-axis 1080 is positive toward the crown 110 and negative toward the sole 112. The Z'-axis 1090 extends in the front-rear direction parallel to the ground contact surface 1010 and is orthogonal to both the X'-axis 1070 and the Y'-axis 1080. The Z'-axis 1090 is positive toward the striking face 102 and negative toward the rear end 111.

[0055] The term or phrase "moment of inertia" (hereinafter, "MOI") can refer to a value derived using the center of gravity (CG) position. "MOI" xx " or "I" xx " can refer to the MOI measured about the X'-axis 1070. The term "MOIyy" or "I" yy " can refer to the MOI measured about the Y'-axis 1080. The term "MOIzz" or "I" zz " can refer to the MOI measured about the Z'-axis 1090. The MOIxx, MOIyy, and MOIzz of the MOI values determine how tolerant the club head 100 is to off-center impact with a golf ball.

[0056] MOI is a metric of the resistance of an object to torsion about a given axis and is calculated according to Equation 1 below.

Equation

[0057] Equation 1 defines the MOI of an object represented by I as the integral of the product of the square of the perpendicular distance between the axis about which the MOI is measured and the position of the mass of the object represented by r with respect to the mass (represented by dm). Generally, when the center of gravity (CG) of an object is known, it is known that the object can be treated as a point mass located at its CG. By treating the object as a point mass, Equation 1 can be simplified to the following Equation 2.

Number

[0058] Equation 2 describes that the moment of inertia I of an object about a given axis is equal to the sum of the masses of all the point masses of the object multiplied by the perpendicular distance between the axis about which the MOI is measured and each point mass.

[0059] As used herein, the term "striking face" refers to the front face of a clubhead configured to strike a golf ball. The term "striking face" can be used interchangeably with the term "face".

[0060] As used herein, the term "striking face perimeter" can refer to the edge of the striking face. The striking face perimeter can be located along the outer edge of the striking face where the curvature of the clubhead deviates from the bulge curvature and / or roll curvature (defined below) of the striking face. Referring to FIG. 5, the striking face perimeter includes the upper edge 118 that defines the highest point on the striking face 102. The striking face perimeter further includes the leading edge 103, which defines the lowest point of the striking face 102. The striking face perimeter is the outermost boundary of the striking face 102.

[0061] The "leading edge" of the clubhead described herein can be identified as the lowermost portion of the striking face perimeter. For example, as shown in FIG. 5, the leading edge 103 is the transition from the striking face 102 to the sole 112 of the clubhead 100.

[0062] The "striking face height" H of the club head used in this specification SF refers to the measured distance from the lowest point of the periphery of the striking face to the highest point of the periphery of the striking face. Referring to FIGS. 5 and 6, the height H SF can be measured parallel to the loft face 1015 from the leading edge 103 to the upper edge 118 of the striking face 102, and the upper edge 118 represents the most crown-side portion of the periphery of the striking face 102.

[0063] The "striking face width" W of the club head used in this specification SF refers to the horizontal distance measured across the striking face in the direction from heel to toe. Referring to FIG. 5, the striking face width W SF can be measured parallel to the ground contact surface 1010 from the most heel-side range of the periphery of the striking face to the most toe-side range of the periphery of the striking face.

[0064] The "geometric center" of the striking face used in this specification refers to the geometric center point of the periphery of the striking face illustrated in FIGS. 2 and 5. The geometric center point 120 of the striking face 102 can be arranged according to the definition of a golf governing body such as the United States Golf Association (USGA).

[0065] As shown in FIG. 6, the striking face 102 has a geometric center height H FC The geometric center height H FC is measured parallel to the loft face 1015 from the leading edge 103 to the geometric center 120.

[0066] The striking face has a "bulge curvature" and a "roll curvature". The bulge curvature is the curvature of the striking face in the direction from heel to toe. The roll curvature is the curvature of the striking face in the direction from crown to sole. The bulge curvature and the roll curvature each have a "bulge radius" and a "roll radius" that define the radius of curvature associated with each of the bulge curvature and the roll curvature. The bulge curvature and / or the roll curvature can have one or more radii.

[0067] As shown in FIG. 6, the club head 100 further includes a line of force 125 that intersects the geometric center 120 and extends parallel to the loft plane 1015. The launch characteristics of the golf ball depend on the relationship between the line of force 125 and the CG 160. The closer the CG 160 is to the line of force 125, the greater the energy transfer between the club head 100 and the golf ball at impact. Even if the CG 160 moves relative to the rest of the club head 100, as long as the distance between the CG 160 and the line of force 125 remains constant, the launch characteristics of the club head 100 at impact remain substantially consistent.

[0068] Before any embodiment of the present disclosure is described in detail, it is to be understood that the present disclosure is not limited to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings in its application. The present disclosure is capable of other embodiments and of being practiced or carried out in various ways.

[0069] (Detailed Description) The golf club head described in this specification has various features and characteristics for maximizing performance considering a specific moment of inertia target value. In particular, the club head described below may be designed to achieve a specific Iyy target and maximize performance and tolerance with respect to the limits of the Iyy target. Generally, a higher Iyy provides a more forgiving club head. A club head with a higher Iyy has a greater resistance to rotation upon impact of a shot on the heel side or toe side from the center. Also, a club head with a high Iyy retains more energy upon impact of a mishit to the heel side or toe side. Thus, generally, a club head with a high Iyy results in a faster ball speed and carry distance with a mishit to the heel side or toe side. However, there are also other factors that contribute to the tolerance and overall performance of the club head, such as the moment of inertia Ixx, bulge curvature, and roll curvature. The embodiments described in this specification provide features and characteristics that increase Ixx with respect to the Iyy target. The embodiments described in this specification further include an optimized bulge curvature and roll curvature determined by combining the Iyy target with other club head characteristics (i.e., Ixx, CG position, coefficient of restitution, etc.). Increasing Ixx can increase the usability and distance upon a mishit to the crown side or sole side. By optimizing the bulge curvature and roll curvature, the carry distance tolerance can be further increased by canceling out the gear effect imparted to the golf ball upon an off-center strike. In particular, the embodiments described in this specification are directed to a driver type golf club head having a specific Iyy target (designed to be primarily used for hitting a golf ball from a tee). This embodiment is not directed to a fairway wood type, hybrid type, or iron type club head. The driver type club head described in this specification is intended to hit a golf ball from a tee, but the club head may also be suitable for hitting a golf ball from the ground.

[0070] As described above, there are two main clubhead characteristics that provide improved performance relative to a fixed Iyy target: 1) the moment of inertia Ixx, and 2) the bulge curvature and roll curvature. The clubhead of the present disclosure provides a high moment of inertia Ixx relative to the Iyy target. In many embodiments, the clubhead can have an Ixx / Iyy ratio that exceeds 0.80. Providing a high Ixx relative to the Iyy target increases the overall forgiveness of the clubhead. Ixx represents the resistance of the clubhead to rotation about the X' axis in a golf shot struck above or below the center. As explained in the above definition, the X' axis is the axis from heel to toe with respect to the coordinate system centered on the clubhead CG. The X' axis extends horizontally through the CG in the direction from heel to toe. In particular, the higher the Ixx / Iyy ratio, the greater the resistance to rotation about the X' axis at impact of a shot in the crown direction or sole direction relative to the center, resulting in a clubhead. Increasing the Ixx / Iyy ratio reduces the effect of rotation of the clubhead about the X' axis and balances the backspin of the golf ball, increasing the carry distance of the golf shot in the event of a mishit in the crown direction or sole direction.

[0071] The club head of the present invention maximizes the Ixx / Iyy ratio by having a "cube-like" shaping and distributing most of the mass of the club head near the Y'-axis. The club head has a cube-like profile where the body width, body height, and body depth are more similar to each other than the width, height, and depth of prior art club heads. The cube-like profile of the club head positions the mass of the crown and sole away from the X'-axis, thereby increasing Ixx without contributing to Iyy. Most prior art club heads, especially the latest club heads, have a flatter, wider, and deeper profile, and the body height is significantly smaller than the body width or body depth. Such prior art club heads prioritize increasing Iyy rather than focusing on Ixx. The shape of these prior art club heads efficiently increases Iyy by shaping the mass of the club head away from the Y'-axis. However, such a design does not prioritize the amount of structural mass away from the X'-axis, so the Ixx / Iyy ratio is not maximized.

[0072] To maximize the Ixx / Iyy ratio, the club head of the present invention efficiently distributes the mass to contribute to Ixx without contributing to Iyy. The club head can distribute a large proportion of the mass near the Y'-axis but far from the X'-axis. To achieve this mass distribution, the club head can include one or more weighting features such as internal mass pads or removable weights located near the Y'-axis and far from the X'-axis. Any such features can serve to provide a significant increase in Ixx relative to Iyy, thereby providing an increased Ixx / Iyy ratio.

[0073] The club head can further comprise a striking face having a bulge curvature and a roll curvature optimized to enhance performance and forgiveness. The bulge curvature and the roll curvature can be adjusted specifically for a particular club head based on the characteristics of the club head, including Ixx, Iyy, CG position, coefficient of restitution, and / or other club head characteristics. The club head of the present invention can satisfy the relationship of one or more bulge radii or roll radii in order to maximize carry distance and forgiveness. The bulge radius and the roll radius of the club head of the present invention cancel out the gear effect imparted to the golf ball during off-center strikes. By providing the bulge radius and the roll radius as a function of club head characteristics, even when the Iyy target is substantially low, forgiveness and carry distance can be increased and a higher performance club head can be provided. In embodiments where the Iyy target is substantially low, the optimized bulge radius and roll radius can compensate for the loss of forgiveness and ball speed associated with the low Iyy target.

[0074] In many embodiments, the club head can further comprise an adjustable swing weight system that provides a consistent Iyy target for a plurality of available club head builds. The adjustable swing weight system includes a plurality of interchangeable and / or removable weight inserts each configured to provide a consistent contribution to Iyy. The adjustable swing weight system provides the ability to vary the total club head mass by more than 25 grams while keeping Iyy constant between different builds.

[0075] I. Iyy Target and Mass Characteristics As described above, the club head of the present invention is designed to achieve a specified target value of the moment of inertia Iyy (hereinafter "Iyy target"). In some embodiments, the Iyy target value can substantially coincide with the limit value of the moment of inertia imposed by the USGA for a conforming club head. However, in many embodiments, the Iyy target value can be lower than the USGA limit value. A club head designed to achieve the USGA limit value or an Iyy target close thereto can be referred to herein as a "high MOI" club head, while a club head designed to achieve an Iyy target significantly lower than the USGA limit value can be referred to herein as a "low MOI" club head. The embodiments and examples in this document are mainly directed to low MOI club heads, but any combination of the principles, properties, features, elements, or methods disclosed below can also be applied to high MOI club heads. Unless otherwise specified, the mass characteristics described in this document, including the moment of inertia value and the position of the CG, reflect a "fully built" club head. A fully built club head includes all applicable weight inserts, removable weights, permanent weights, swing weights, fillers, and / or other removable components such as those associated with an adjustable hosel assembly.

[0076] In embodiments of a high MOI club head, the Iyy target can be between 4000 g*cm 3 and 8000 g*cm 3の In some embodiments of high MOI club heads, the Iyy target is between 4000 g*cm 3 and 4200 g*cm 3 between 4200 g*cm 3 and 4400 g*cm 3 between 4400 g*cm 3 and 4600 g*cm 3 between 4600 g*cm 3 and 4800 g*cm 3 between 4800 g*cm 3 and 5000 g*cm 3 between 5000 g*cm 3and between 5200 g*cm 3 and 5200 g*cm 3 from 5400 g*cm 3 and 5400 g*cm 3 from 5600 g*cm 3 and 5600 g*cm 3 from 5800 g*cm 3 and, or 5800 g*cm 3 from 6000 g*cm 3 and 6000 g*cm 3 and 6500 g*cm 3 and 6500 g*cm 3 and 7000 g*cm 3 and 7000 g*cm 3 and 7500 g*cm 3 and, or 7500 g*cm 3 and 8000 g*cm 3 and can be. In some embodiments of the high MOI clubhead, the Iyy target is greater than 4000 g*cm 3 greater than, greater than 4200 g*cm 3 greater than, greater than 4400 g*cm 3 greater than, greater than 4600 g*cm 3 greater than, greater than 4800 g*cm 3 greater than, greater than 5000 g*cm 3 greater than, greater than 5200 g*cm 3 greater than, greater than 5400 g*cm 3 greater than, greater than 5600 g*cm 3 greater than, or greater than 5800 g*cm 3 greater than, greater than 6000 g*cm 3 greater than, greater than 6500 g*cm 3 greater than, greater than 7000 g*cm 3 greater than, greater than 7500 g*cm 3 greater than, or greater than 8000 g*cm 3 greater than and can be. Embodiments of the high MOI clubhead can have a moment of inertia Iyy within any of the above Iyy target ranges.

[0077] In embodiments of the low MOI clubhead, the Iyy target is 2000 g*cm3 and 4000 g*cm 3 and can be between. In some embodiments of the low MOI club head, the Iyy target is 2000 g*cm 3 and 2200 g*cm 3 between, 2200 g*cm 3 and 2400 g*cm 3 between, 2400 g*cm 3 and 2600 g*cm 3 between, 2600 g*cm 3 and 2800 g*cm 3 between, 2800 g*cm 3 and 3000 g*cm 3 between, 3000 g*cm 3 and 3200 g*cm 3 between, 3200 g*cm 3 and 3400 g*cm 3 between, 3400 g*cm 3 and 3600 g*cm 3の between, 3600 g*cm 3 and 3800 g*cm 3 between, or 3800 g*cm 3 and 4000 g*cm 3 and can be between. In some embodiments of the low MOI club head, the Iyy target is 4000 g*cm 3 less than, 3800 g*cm 3 less than, 3600 g*cm 3 less than, 3400 g*cm 3 less than, 3200 g*cm 3 less than, 3000 g*cm 3 less than, 2800 g*cm 3 less than, 2600 g*cm 3 less than, 2400 g*cm 3 less than, 2200 g*cm 3 less than, or 2000 g*cm 3 less than and can be. Embodiments of the low MOI club head can have an Iyy moment of inertia within any of the above Iyy target ranges.

[0078] As described above, the club head described in this specification achieves a high Ixx / Iyy ratio (greater than 0.80) by having a cubic-like shape and distributing most of the club head mass near the Y' axis. Thus, the club head can have an Ixx value that is substantially close to the Iyy target value. In embodiments of the high MOI club head, the club head has an Ixx between 3200 g*cm 3 and 7200 g*cm 3 . In some embodiments of the high MOI club head, the Ixx is between 3200 g*cm 3 and 3600 g*cm 3 , between 3600 g*cm 3 and 4000 g*cm 3 , between 4000 g*cm 3 and 4400 g*cm 3 , between 4400 g*cm 3 and 4800 g*cm 3 , between 4800 g*cm 3 and 5200 g*cm 3 , between 5200 g*cm 3 and 5600 g*cm 3 , between 5600 g*cm 3 and 6000 g*cm 3 , between 6000 g*cm 3 and 6400 g*cm 3 , between 6400 g*cm 3 and 6800 g*cm 3 , or between 6800 g*cm 3 and 7200 g*cm 3 . In some embodiments of the high MOI club head, the Ixx is greater than 3200 g*cm 3 , greater than 3600 g*cm 3 , greater than 4000 g*cm 3 , greater than 4400 g*cm 3 , greater than 4800 g*cm 3 , greater than 5200 g*cm 3 , greater than 5600 g*cm 3 , greater than 6000 g*cm 3 , greater than 6400 g*cm 3Greater than, 6800 g*cm 3 Greater than, or 7200 g*cm 3 Can be made greater.

[0079] In embodiments of the low MOI club head, the club head can have an Ixx between 1400 g*cm 3 and 3600 g*cm 3 . In some embodiments of the low MOI club head, the Ixx can be between 1400 g*cm 3 and 1600 g*cm 3 , between 1600 g*cm 3 and 1800 g*cm 3 , between 1800 g*cm 3 and 2000 g*cm 3 , between 2000 g*cm 3 and 2200 g*cm 3 , between 2200 g*cm 3 and 2400 g*cm 3 , between 2400 g*cm 3 and 2600 g*cm 3 , between 2600 g*cm 3 and 2800 g*cm 3 , between 2800 g*cm 3 and 3000 g*cm 3 , between 3000 g*cm 3 and 3200 g*cm 3 , between 3200 g*cm 3 and 3400 g*cm 3 , or between 3400 g*cm 3 and 3600 g*cm 3 . In some embodiments of the low MOI club head, the Ixx is greater than 1400 g*cm 3 , greater than 1600 g*cm 3 , greater than 1800 g*cm 3 , greater than 2000 g*cm 3 , greater than 2200 g*cm 3 , greater than 2400 g*cm 3 , greater than 2600 g*cm 3 , greater than 2800 g*cm 3 , greater than 3000 g*cm3 Greater than, 3200 g*cm 3 Greater than, 3400 g*cm 3 Greater than, or 3600 g*cm 3 It can be made greater than.

[0080] The CG160 position of the club head 100 can vary based on the Iyy target, club head volume, and other factors. In high MOI embodiments, the club head 100 can be provided with a CGy position measured from the geometric center 120 of the striking face 102 between 0 inches and -0.5 inches. In some high MOI embodiments, the CGy position can be between 0 inches and -0.05 inches, between -0.05 inches and -0.10 inches, between -0.10 inches and -0.15 inches, between -0.15 inches and -0.20 inches, between -0.20 inches and -0.25 inches, between -0.25 inches and -0.30 inches, between -0.35 inches and -0.40 inches, between -0.40 inches and -0.45 inches, or between -0.45 inches and -0.50 inches. In some high MOI embodiments, the CGy position can be less than 0 inches, less than -0.05 inches, less than -0.10 inches, less than -0.15 inches, less than -0.20 inches, less than -0.25 inches, less than -0.30 inches, less than -0.35 inches, less than -0.40 inches, less than -0.45 inches, or less than -0.50 inches.

[0081] In high-MOI embodiments, the club head 100 can have a CGz position measured between -1.25 inches and -2.0 inches from the geometric center 120 of the striking face 102. In some high-MOI embodiments, the CGz position can be between -1.25 inches and -1.30 inches, between -1.30 inches and -1.35 inches, between -1.35 inches and -1.40 inches, between -1.40 inches and -1.45 inches, between -1.45 inches and -1.50 inches, between -1.50 inches and -1.55 inches, between -1.55 inches and -1.60 inches, between -1.60 inches and -1.65 inches, between -1.65 inches and -1.70 inches, between -1.70 inches and -1.75 inches, between -1.75 inches and -1.80 inches, between -1.80 inches and -1.85 inches, between -1.85 inches and -1.90 inches, between -1.90 inches and -1.95 inches, or between -1.95 inches and -2.0 inches. In some high-MOI embodiments, the CGz position can be less than -1.25 inches, less than -1.30 inches, less than -1.35 inches, less than -1.40 inches, less than -1.45 inches, less than -1.50 inches, less than -1.55 inches, less than -1.60 inches, less than -1.65 inches, less than -1.70 inches, less than -1.75 inches, less than -1.80 inches, less than -1.85 inches, less than -1.90 inches, less than -1.95 inches, or less than -2.0 inches.

[0082] In a low MOI embodiment, the club head 100 can be provided with a CGy position measured from the geometric center 120 of the hitting face 102 between -0.30 inches and 0.30 inches. In some low MOI embodiments, the CGy position can be between -0.30 inches and -0.25 inches, between -0.25 inches and -0.20 inches, between -0.20 inches and -0.15 inches, between -0.15 inches and -0.10 inches, between -0.10 inches and -0.05 inches, between -0.05 inches and 0 inches, between 0 inches and 0.05 inches, between 0.05 inches and 0.10 inches, between 0.10 inches and 0.15 inches, between 0.15 inches and 0.20 inches, between 0.20 inches and 0.25 inches, or between 0.25 inches and 0.30 inches. In some low MOI embodiments, the CGy position can be less than 0.30 inches, less than 0.25 inches, less than 0.20 inches, less than 0.15 inches, less than 0.10 inches, less than 0.05 inches, less than 0 inches, less than -0.05 inches, less than -0.10 inches, less than -0.15 inches, less than -0.20 inches, less than -0.25 inches, or less than -0.30 inches.

[0083] In a low MOI embodiment, the club head 100 can have a CGz position measured from the geometric center 120 of the hitting face 102 between -1.0 inches and -1.75 inches. In some low MOI embodiments, the CGz position can be between -1.0 inch and -1.05 inches, between -1.05 inches and -1.10 inches, between -1.10 inches and -1.15 inches, between -1.15 inches and -1.20 inches, between -1.20 inches and -1.25 inches, between -1.25 inches and -1.30 inches, between -1.30 inches and -1.35 inches, between -1.35 inches and -1.40 inches, between -1.40 inches and -1.45 inches, between -1.45 inches and -1.50 inches, between -1.50 inches and -1.55 inches, between -1.55 inches and -1.60 inches, between -1.60 inches and -1.65 inches, between -1.65 inches and -1.70 inches, or between -1.70 inches and -1.75 inches. In some high MOI embodiments, the CGz position can be less than -1.0 inch, less than -1.05 inches, less than -1.10 inches, less than -1.15 inches, less than -1.20 inches, less than -1.25 inches, less than -1.30 inches, less than -1.35 inches, less than -1.40 inches, less than -1.45 inches, less than -1.50 inches, less than -1.55 inches, less than -1.60 inches, less than -1.65 inches, less than -1.70 inches, or less than -1.75 inches.

[0084] In many embodiments (high MOI or low MOI), the position of CG160 can be characterized by the perpendicular distance between CG160 and the line of force 125 (defined above as the axis extending through the geometric center 120 and parallel to the loft plane 1015). In many embodiments, CG160 is positioned substantially close to the line of force 125 to provide maximum energy transfer between the club head 100 and the golf ball in a shot struck at the geometric center 120. In many embodiments, CG160 can be positioned within 0.05 inches of the line of force 125. In many embodiments, CG160 can be positioned within 0.045 inches, 0.040 inches, 0.035 inches, 0.030 inches, 0.025 inches, 0.020 inches, 0.015 inches, or 0.010 inches of the line of force 125.

[0085] II. Ixx / Iyy ratio The club head has a high moment of inertia Ixx with respect to the Iyy target. For a fixed Iyy target, increasing Ixx is extremely important in increasing the performance and forgiveness of the club head. Therefore, the club head has a high Ixx / Iyy ratio. In many embodiments, the club head can have an Ixx / Iyy ratio between 0.80 and 1.0. In some embodiments, the club head can have an Ixx / Iyy ratio greater than 0.82, greater than 0.84, greater than 0.85, greater than 0.86, greater than 0.88, or greater than 0.90. As will be described in more detail in the following examples, the present club head has a greater than 3%, greater than 5%, greater than 10%, greater than 15%, greater than 20%, greater than 25%, greater than 30%, greater than 35%, greater than 40%, greater than 45%, or greater than 50% increased Ixx / Iyy ratio compared to prior art club heads that focused only on maximizing Iyy. For example, many prior art club heads have an Ixx / Iyy ratio between 0.6 and 0.77. Therefore, providing a club head with an Ixx / Iyy ratio of 0.8 will result in an increase of 4% to 33% compared to the prior art, depending on which prior art club head is considered. Providing club heads with even larger Ixx / Iyy ratios (greater than 0.82, greater than 0.84, etc.) means even greater increases compared to the prior art. This increased Ixx / Iyy can be achieved by shaping the club head like a cube and distributing most of the mass of the club head near the Y' axis.

[0086] a. Cubic club head shaping As described above, a club head having a predetermined Iyy target value can have a high Ixx / Iyy ratio to improve performance. Shaping the club head is fundamental to efficiently maximizing the Ixx / Iyy ratio. The shape of the club head body determines where discretionary mass can be placed. FIGS. 1-10 show a club head 100 having a cube-like shape configured to increase the Ixx / Iyy ratio. A cube-like profile places much of the club head's mass away from the X'-axis 1070 (i.e., towards the crown 110 and sole 112) and near the Y'-axis 1080. Placing mass away from the X'-axis 1070 increases Ixx, thereby reducing rotation about the X'-axis 1070 at impact and balancing the spin imparted to the golf ball. By providing mass near the Y'-axis 1080, the contribution to Iyy is low, and the club head 100 can be maintained at the desired Iyy target. A cube-like profile provides a relatively high body height compared to prior art club heads that are flatter, which effectively increases the distance of the crown 110 and sole 112 from the X'-axis 1070. Thus, the mass of the crown 110 and sole 112 increases the contribution to Ixx without increasing the contribution to Iyy. A cube-like profile increases Ixx without significantly increasing Iyy, thereby providing a higher Ixx / Iyy ratio. In contrast, prior art club heads attempt to maximize Iyy without much consideration for Ixx. Thus, such prior art club heads tend to place discretionary mass deep (i.e., near the trailing edge 111) and wide (i.e., near the heel 104 and toe 106) to provide mass as far away from the Y'-axis as possible.

[0087] Compared to a prior art club head that is flatter and wider, the club head of the present invention has a body width W B and a body depth D B that may have a body height H B substantially similar to that of the prior art. Compared to the prior art, the dimensions of the cube-like body result in a body height H that is greater than that of the flatter prior art design.B Increasing the body width W B and decreasing the body depth D B can be achieved by or a combination thereof. Referring to FIG. 2, the club head 100 has a body height H B (defined above) measured between the ground plane 1010 and the highest point of the crown 110 B and can include. In some embodiments, the body height H B can be from 2.0 to 3.0 inches. In some embodiments, the body height H B can be between 2.0 inches and 2.1 inches, between 2.1 inches and 2.2 inches, between 2.2 inches and 2.3 inches, between 2.3 inches and 2.4 inches, between 2.4 inches and 2.5 inches, between 2.5 inches and 2.6 inches, between 2.6 inches and 2.7 inches, between 2.7 inches and 2.8 inches, between 2.8 inches and 2.9 inches, or between 2.9 inches and 3.0 inches. In some embodiments, the body height H B can be greater than 2.0 inches, greater than 2.1 inches, greater than 2.2 inches, greater than 2.3 inches, greater than 2.4 inches, greater than 2.5 inches, greater than 2.6 inches, greater than 2.7 inches, greater than 2.8 inches, greater than 2.9 inches, or greater than 3.0 inches. In many embodiments, the body height H B can be substantially higher than the body width W B and the body depth D B .

[0088] The club head 100 can further include a body width W B (defined above) measured between the heel apex 116 and the toe apex 119. In some embodiments, the body width W B can be from 3 to 5 inches. In some embodiments, the body width W Bcan be between 3.0 inches and 3.2 inches, between 3.2 inches and 3.4 inches, between 3.4 inches and 3.6 inches, between 3.6 inches and 3.8 inches, between 3.8 inches and 4.0 inches, between 4.0 inches and 4.2 inches, between 4.2 inches and 4.4 inches, between 4.4 inches and 4.6 inches, between 4.6 inches and 4.8 inches, or between 4.8 inches and 5.0 inches. In some embodiments, the body width W B can be less than 5.0 inches, less than 4.8 inches, less than 4.6 inches, less than 4.4 inches, less than 4.2 inches, less than 4.0 inches, less than 3.8 inches, less than 3.6 inches, less than 3.4 inches, less than 3.2 inches, or less than 3.0 inches. In many low MOI embodiments, the body width W B can be substantially narrower than the width of prior art club heads. In many low MOI embodiments, the body width W B can be less than 4.5 inches.

[0089] Referring to FIG. 4, the club head 100 can further include a body depth D B (as defined above) measured between the leading edge 103 and the rearmost point 117 of the body 101. In some embodiments, the body depth D B can be from 3 to 5 inches. In some embodiments, the body depth D B can be between 3.0 inches and 3.2 inches, between 3.2 inches and 3.4 inches, between 3.4 inches and 3.6 inches, between 3.6 inches and 3.8 inches, between 3.8 inches and 4.0 inches, between 4.0 inches and 4.2 inches, between 4.2 inches and 4.4 inches, between 4.4 inches and 4.6 inches, between 4.6 inches and 4.8 inches, or between 4.8 inches and 5.0 inches. In some embodiments, the body depth D Bcan be less than 5.0 inches, less than 4.8 inches, less than 4.6 inches, less than 4.4 inches, less than 4.2 inches, less than 4.0 inches, less than 3.8 inches, less than 3.6 inches, less than 3.4 inches, less than 3.2 inches, or less than 3.0 inches. In many low MOI embodiments, the body depth D B can be substantially narrower than the depth of prior art club heads. In many low MOI embodiments, the body depth D B can be less than 4.0 inches.

[0090] The cuboid-like shape of the club head 100 is characterized by the ratio of the body height H B to the body width W B defined as H B / W B In many embodiments, the H B / W B ratio can be between 0.50 and 0.75. In some embodiments, the H B / W B ratio can be between 0.50 and 0.55, between 0.55 and 0.60, between 0.60 and 0.65, between 0.65 and 0.70, or between 0.70 and 0.75. In some embodiments, the H B / W B ratio can be greater than 0.50, greater than 0.55, greater than 0.60, greater than 0.65, greater than 0.70, or greater than 0.75. By providing a high H B / W B ratio, the club head 100 provides a cuboid-like shape that places mass away from the X' axis and near the Y' axis.

[0091] Similarly, the cuboid-like shape of the club head 100 is characterized by the ratio of the body height H B to the body depth D B defined as H B / D B In many embodiments, the H B / D BThe ratio can be from 0.5 to 0.75. In some embodiments, H B / D B The ratio can be between 0.50 and 0.55, between 0.55 and 0.60, between 0.60 and 0.65, between 0.65 and 0.70, or between 0.70 and 0.75. In some embodiments, H B / D B The ratio can be greater than 0.50, greater than 0.55, greater than 0.60, greater than 0.65, greater than 0.70, or greater than 0.75. Providing a high H B / D B ratio causes the club head 100 to provide a cube-like shape that positions mass away from the X' axis and near the Y' axis. Thus, the cube-like shape increases the moment of inertia Ixx without contributing significantly to increasing Iyy beyond a target value. In many embodiments, H B / W B ratio and H B / D B ratio are each less than 0.50 H B / W B ratio and H B / D B ratio can be made substantially larger than a flatter prior art club head with such H

[0092] The cube-like shape of the club head 100 can be further characterized by the sum of the H B / W B ratio and the H B / D B ratio. A club head that is completely cube-shaped would have an H B / W B ratio and an H B / D B ratio each equal to 1. Thus, the completely cube-shaped club head would have a sum of H B / W B ratio and H B / D B ratio equal to 2. In many embodiments, the current club head 100 has an H B / WB Ratio and H B / D B can include the sum of the ratios. In some embodiments, the club head 100 has an H greater than 1.2, greater than 1.25, greater than 1.30, greater than 1.35, greater than 1.40, greater than 1.45, or greater than 1.50 B / W B ratio and H B / D B and can include the sum of the ratios. Thus, in many embodiments, the club head can be between 60% and 75% of that of a perfectly cubic club head in terms of H B / W B ratio and H B / D B and can include the sum with the ratio. In many embodiments, H B / W B ratio and H B / D B The sum of the ratios can be made substantially larger than that of a flatter prior art club head, which tends to have a sum value of 1.00 or less.

[0093] Referring to FIG. 7, the cube - like shape of the club head 100 can be further characterized in relation to the volume of a reference cube 125. The club head 100 can define the reference cube 125, and the length of each side of the reference cube 125 is equal to the body width W B and thereby the reference cube 125 has a volume equal to the cube of the body width W (W B to the power of 3 (W B 3) defines a cubic reference volume. The club head 100 can define a cubic volume ratio defined as the club head volume divided by the cubic reference volume. In many embodiments, the club head 100 can define a cubic volume ratio between 0.28 and 0.40. In some embodiments, the club head 100 can have a cubic volume ratio greater than 0.28, greater than 0.29, greater than 0.30, greater than 0.31, greater than 0.32, greater than 0.33, greater than 0.34, greater than 0.35, greater than 0.36, greater than 0.37, greater than 0.38, greater than 0.39, or greater than 0.40.

[0094] The larger the cubic volume ratio, the closer the shape of the club head 100 is to a cube. For example, a club head 100 having a cube shape has a body 101 that is tall relative to the body width W B and the body depth D B . Thus, a club head 100 having a cube shape effectively "fills" a larger proportion of the reference cube 125. In contrast, many prior art club heads have a shorter and flatter profile. Accordingly, such prior art club heads fill a smaller proportion of the reference cube defined by the prior art body width. Many prior art club heads with a flatter body profile have a cubic volume ratio of less than 0.25.

[0095] The club head 100 can further include a gentle crown angle 172 that contributes to a cube-like shape. As shown in FIG. 6, the club head 100 includes a crown axis 170 that extends between a crown transition point 174 and a rear transition point 176. Both the crown transition point 174 and the rear transition point 176 can be located within the YZ plane. The crown transition point 174 can be located at the foremost point of the crown 110 within the YZ plane. At the crown transition point 174, the curvature of the crown conforms to the transition curvature between the crown 110 and the hitting face 102. The rear transition point 176 can be located at the rearmost point of the crown 110 within the YZ plane. At the rear transition point 176, the curvature of the crown conforms to the transition curvature between the crown 110 and the rear end 111.

[0096] The club head 100 includes a crown angle 170 measured as the acute angle between the crown axis 170 and the Y-axis 1050. In many embodiments, the club head 100 includes a crown angle 170 between 75° and 89°. In some embodiments, the club head 100 includes a crown angle 170 that is greater than 75°, greater than 76°, greater than 77°, greater than 78°, greater than 79°, greater than 80°, greater than 81°, greater than 82°, greater than 83°, greater than 84°, greater than 85°, greater than 86°, greater than 87°, greater than 88°, or greater than 89°.

[0097] Prior art club heads generally have a steep crown angle to lower the center of gravity of the club head. Therefore, the crown angle 170 within the range listed above can be substantially larger compared to the prior art. The large crown angle 170 of this club head 100 provides a crown 110 that slopes gradually downward from the front end 108 to the rear end 111. The large crown angle 170 raises the CG160, thereby increasing the Ixx contribution of any discretionary mass located near the sole 112. Further, the large crown angle 170 increases the distance between the mass forming the crown 110 and the X' axis 1070, but has a negligible effect on the distance between the mass of the crown and the Y' axis 1080. Thus, as the crown angle 170 increases, the contribution to Iyy is negligible while the contribution to Ixx increases, and the Ixx / Iyy ratio increases.

[0098] Referring to FIGS. 5 and 6, the cube-like shape of the club head 100 can be further characterized by the dimensions of the striking face 102. The club head 100 can have a substantially square striking face profile where the striking face height H SF and the striking face width W SF are substantially similar to each other. As shown in FIGS. 5 and 6, the club head 100 can have a striking face height H between 1.5 inches and 2.75 inches SF (as defined above). In some embodiments, the striking face height H SF can be between 1.5 inches and 1.75 inches, between 1.75 inches and 2.0 inches, between 2.0 inches and 2.25 inches, between 2.25 inches and 2.50 inches, or between 2.50 inches and 2.75 inches. In some embodiments, the striking face height H SF can be greater than 1.5 inches, greater than 1.75 inches, greater than 2.0 inches, greater than 2.25 inches, greater than 2.50 inches, or greater than 2.75 inches. Due to the cube-like shape of the club head 100, the height H of the striking face SFcan be made substantially taller compared to the relative height and width of the prior art striking face, the width W of the striking face SF with respect to.

[0099] Furthermore, the club head 100 can have a striking face width W between 2.0 inches and 3.75 inches SF (as defined above). In some embodiments, the striking face width W SF can be between 2.0 inches and 2.25 inches, between 2.25 inches and 2.50 inches, between 2.50 inches and 2.75 inches, between 2.75 inches and 3.0 inches, between 3.0 inches and 3.25 inches, between 3.25 inches and 3.50 inches, or between 3.50 inches and 3.75 inches. In some embodiments, the striking face width W SF can be less than 3.75 inches, less than 3.50 inches, less than 3.25 inches, less than 3.0 inches, less than 2.75 inches, less than 2.50 inches, less than 2.25 inches, or less than 2.0 inches. Due to the cubical-like shape of the club head 100, the striking face width W SF can be made substantially narrower in relation to a shorter and wider prior art striking face. In many low MOI embodiments, the striking face width W SF can be less than 3.0 inches.

[0100] The substantially square profile of the striking face 102 can be characterized by a striking face aspect ratio. The striking face aspect ratio is the striking face height H SF divided by the striking face width W SFIt is defined as the ratio divided by [[ID=]]. In many embodiments, the face aspect ratio can be between 0.70 and 0.90. In some embodiments, the face aspect ratio can be between 0.70 and 0.72, between 0.72 and 0.74, between 0.74 and 0.76, between 0.76 and 0.78, between 0.78 and 0.80, between 0.80 and 0.82, between 0.82 and 0.84, between 0.84 and 0.86, between 0.86 and 0.88, or between 0.88 and 0.90. In some embodiments, the face aspect ratio can be greater than 0.70, greater than 0.72, greater than 0.74, greater than 0.76, greater than 0.78, greater than 0.80, greater than 0.82, greater than 0.84, greater than 0.86, greater than 0.88, or greater than 0.90. The club head 100 of the present invention has a higher aspect ratio than the shorter and flatter face of the prior art club heads. The substantially square profile of the face 102 corresponds to the cube-like shape of the profile of the entire club head, and all of these contribute to an increase in the Ixx / Iyy ratio.

[0101] The club head 100 can have a club head volume suitable for a driver type club head. In embodiments with a high MOI, the club head 100 can have a volume between 350 g·cm 3 and 460 g·cm 3 In some high MOI embodiments, the club head 100 can have a volume between 350 g·cm 3 and 370 g·cm 3 between 370 g·cm 3 and 390 g·cm 3 between 390 g·cm 3 and 410 g·cm 3 between 410 g·cm 3 and 430 g·cm 3 between 430 g·cm 3 and 450 g·cm 3 between 450 g·cm 3 and 460 g·cm 3can have a volume between. In some high MOI embodiments, the club head 100 is 350 g*cm 3 greater than, 370 g*cm 3 greater than, 390 g*cm 3 greater than, 410 g*cm 3 greater than, 430 g*cm 3 greater than, 450 g*cm 3 greater than, or 460 g*cm 3 greater than.

[0102] In low MOI embodiments, the volume of the club head can be significantly lower than that of typical prior art club heads. A high club head volume will of course increase Iyy. Given a low Iyy target, by providing a lower club head volume, the ability to increase Ixx and arrange discretionary mass in a way that provides a higher Ixx / Iyy ratio is increased. In many embodiments. In many low MOI embodiments, the club head 100 is between 200 cm 3 and 350 cm 3 It may have a volume between. In some low MOI embodiments, the club head 100 is between 200 cm 3 and 220 cm 3 between, 220 cm 3 and 240 cm 3 between, 240 cm 3 and 260 cm 3 between, 260 cm 3 and 280 cm 3 between, 280 cm 3 and 300 cm 3 between, 300 cm 3 and 320 cm 3 between, 320 cm3 and 340 cm 3 between, or 340 cm 3 and 350 cm 3 It may have a volume between. In some low MOI embodiments, the club head 100 is less than 350 cm 3 less than, 340 cm 3 less than, 320 cm 3 less than, 300 cm 3Less than 280 cm 3 Less than 260 cm 3 Less than 240 cm 3 Less than 220 cm 3 Less than, or 200 cm 3 It can have a volume less than

[0103] The cube - like shaping of the club - head body 101 characterized above provides a club - head 100 with an increased Ixx / Iyy ratio. The unique shaping of this club - head can also affect the aerodynamic characteristics of the club - head. Overall, in many low - MOI embodiments, since the size of the club - head 100 is small, the aerodynamic characteristics are improved. As described above, low - MOI embodiments generally have a smaller club - head volume, which is associated with smaller body dimensions (body height H B , body depth D B , and body width W B ), less surface area, and a smaller projected area. Thus, a smaller club - head profile reduces the amount of drag force on the club - head 100 during the swing, allowing the player to swing faster and hit the golf ball farther. However, in some embodiments, a more cubic body shape may be less aerodynamic than a flatter club - head of the same volume. To compensate for any increase in drag associated with the cubic body shape, the club - head 100 can further include one or more aerodynamic features or characteristics such as a turbulator or an aerodynamic transition curvature, all of which are described in more detail below in the "Additional Features" section. Thus, the club - head 100 achieves a balance between the Ixx / Iyy ratio and aerodynamics.

[0104] III. Mass Distribution of the Club - Head In addition to the shape of the club head 100 and the dimensions of the body, the effect of maximizing the Ixx / Iyy ratio depends on the mass distribution of the club head. In particular, achieving a high Ixx / Iyy ratio depends on placing most of the discretionary mass of the club head near the Y'-axis 1080 and away from the X'-axis 1070. By doing so, the discretionary mass significantly contributes to increasing Ixx without increasing Iyy beyond the target value. Accordingly, the club head has a high percentage of its total mass around the Y'-axis 1080. In contrast, many prior art club heads focus only on maximizing Iyy rather than the Ixx / Iyy ratio and attempt to place all of the discretionary mass as far away from the Y'-axis as possible.

[0105] The mass distribution of the club head may be characterized by the amount of mass of the club head located within the central mass zone 130. Referring to FIGS. 8 and 9, the central mass zone 130 is centered on the Y'-axis 1080 and is defined by a virtual cylinder that extends through the entire club head body 101 from the crown 110 to the sole 112. The size of the central mass zone 130 is the central mass zone radius R CMZ which is determined by. The central mass zone radius R CMZ can be between 0.50 inches and 1.5 inches, measured perpendicular to the Y'-axis 1080. In some embodiments, the central mass zone radius can be 0.50 inches, 0.55 inches, 0.60 inches, 0.65 inches, 0.70 inches, 0.75 inches, 0.80 inches, 0.85 inches, 0.90 inches, 0.95 inches, 1.00 inches, 1.05 inches, 1.10 inches, 1.15 inches, 1.20 inches, 1.25 inches, 1.30 inches, 1.35 inches, 1.40 inches, 1.45 inches, or 1.50 inches. In many embodiments, the central mass zone radius R CMZis 0.75 inches. The greater the proportion of the club head mass located within the central mass zone 130, the less the amount that mass contributes to an increase in Iyy while providing a significant increase in Ixx. Thus, the effectiveness of the club head in increasing the Ixx / Iyy ratio may be directly related to the amount of club head mass located within the central mass zone 130.

[0106] In many embodiments, the mass distribution of the club head 100 can be characterized by the proportion of the total club head mass constrained within the central mass zone 130. In some embodiments, between 10% and 50% of the total club head mass can be located within the central mass zone 130. In some embodiments, more than 15%, more than 20%, more than 25%, more than 30%, more than 35%, more than 40%, more than 45%, or more than 50% of the total club head mass can be located within the central mass zone 130. The proportion of the total club head mass located within the central mass zone 130 depends greatly on the selected central mass zone radius R CMZ and. In many embodiments, the mass percentage within the central mass zone 130 can be determined considering a central mass zone radius R of 0.75 inches CMZ . In many embodiments, more than 15%, more than 20%, more than 25%, more than 30%, more than 35%, or more than 40% of the total club head mass can be located within the central mass zone 130 where the radius R CMZ is equal to 0.75 inches.

[0107] In some embodiments, the mass distribution of the club head may be further characterized by the size of a central mass zone 130 that includes a particular percentage of the total club head mass. For example, in some embodiments, 30% of the total club head mass is within a central mass zone radius R that is less than 1.50 inches, less than 1.45 inches, less than 1.40 inches, less than 1.35 inches, less than 1.30 inches, less than 1.25 inches, less than 1.20 inches, less than 1.15 inches, less than 1.10 inches, less than 1.05 inches, less than 1.00 inches, less than 0.95 inches, less than 0.90 inches, less than 0.85 inches, less than 0.80 inches, less than 0.75 inches, less than 0.70 inches, less than 0.65 inches, less than 0.60 inches, less than 0.55 inches, or less than 0.50 inches CMZ can be located in a central mass zone 130 (measured perpendicular to the Y'-axis 1080). Thus, the club head 100 includes a small central mass zone 130 that contains a significant percentage (30%) of the total club head mass. Thereby, a large proportion of the club head mass is disposed near the Y'-axis 1080, increasing the Ixx / Iyy ratio.

[0108] Furthermore, the mass distribution of the club head may be further characterized by a first mass distribution metric (MD1). The first mass distribution metric MD1 quantifies the efficiency of mass placement near the Y'-axis 1080 by relating the percentage of the total club head mass within the central mass zone 130 to the size of the central mass zone 130. The first mass distribution metric MD1 is defined as follows:

Equation

[0109] Furthermore, the mass distribution of the club head may be further characterized by a second mass distribution metric (MD2). The second mass distribution metric MD2 characterizes the amount of mass disposed near the Y'-axis 1080 relative to the volume of the club head 100. The second mass distribution metric MD2 is defined as follows. [Number] Here, M CMZ is the mass within the central mass zone 130, M Tis the total mass of the club head, and V is the volume of the club head. In many embodiments, the club head 100 can have a second mass distribution metric MD2 greater than 0.5. In some embodiments, the club head 100 can have a second mass distribution metric MD2 between 0.50 and 0.55, between 0.55 and 0.60, between 0.60 and 0.65, between 0.65 and 0.70, between 0.70 and 0.75, between 0.75 and 0.80, between 0.80 and 0.85, between 0.85 and 0.90, between 0.90 and 0.95, or between 0.95 and 1.00. In some embodiments, the club head 100 can have a second mass distribution metric MD2 greater than 0.50, greater than 0.55, greater than 0.60, greater than 0.65, greater than 0.70, greater than 0.75, greater than 0.80, greater than 0.85, greater than 0.90, greater than 0.95, or greater than 1.00. Since the club head 100 has a substantially larger proportion of mass and a substantially smaller volume within the central mass zone 130 compared to the prior art, the second mass distribution metric MD2 will be significantly larger than that of the prior art.

[0110] Furthermore, the mass distribution of the club head may be further characterized by a third mass distribution metric (MD3). The third mass distribution metric MD3 characterizes the amount of mass disposed near the Y'-axis 1080 with respect to the club head Iyy. The third mass distribution metric MD3 is defined as follows.

Number

[0111] a. Mass pad In many embodiments, the club head can include one or more weight pads strategically placed to increase the Ixx / Iyy ratio. The one or more weight pads can be integrally formed with a portion of the sole 112, a portion of the crown 110, a portion of the heel 104, a portion of the toe 106, or any combination thereof. As shown in FIG. 10, the club head 100 includes a sole weight pad 140 integrally formed with the inner surface of the sole 112 and extending into the internal cavity 107. Similarly, the club head 100 shown in FIG. 10 includes a crown weight pad 142 integrally formed with the inner surface of the crown 110 and extending into the internal cavity 107. In other embodiments, the club head 100 can include any combination of a crown weight pad, a sole weight pad, or other weight pads placed on different portions of the body 101. Although the sole weight pad 140 and the crown weight pad 142 of the present embodiment are shown and described as being integral with the body 101, in other embodiments, the one or more weight pads can be separate members coupled to the club head body 101 via welding, brazing, mechanical coupling, adhesive bonding, or any other suitable means.

[0112] In many embodiments, the sole mass pad 140 and the crown mass pad 142 can be disposed on or near the Y'-axis 1080 such that all or most of the sole mass pad 140 and / or the crown mass pad 142 fits within the central mass zone 130. In this way, the sole mass pad 140 and the crown mass pad 142 increase the contribution to Ixx with a negligible contribution to Iyy, thereby increasing the Ixx / Iyy ratio. In many embodiments, such as the illustrated embodiment of FIG. 10, the sole mass pad 140 and / or the crown mass pad 142 can intersect the Y'-axis. The proximity of any of the mass pads (i.e., the sole mass pad 140 and / or the crown mass pad 142) to the Y'-axis may be characterized by the size of the central mass zone 130 (described above) that bounds the entire mass pad. For example, in some embodiments, the sole mass pad 140 and / or the crown mass pad 142 have a central mass zone radius R less than 2.00 inches, less than 1.75 inches, less than 1.50 inches, less than 1.25 inches, less than 1.00 inches, less than 0.75 inches, less than 0.50 inches, or less than 0.25 inches CMZ and can be entirely surrounded within the central mass zone 130. The smaller the central mass zone radius R that surrounds the entire mass pad CMZ , the more efficient the mass pad is at increasing the Ixx / Iyy ratio. A mass pad surrounded within a small central mass zone 130 provides a greater contribution to Ixx than to Iyy compared to a similar mass pad of the same mass that does not fit within the central mass zone 130. For example, a 20-gram mass pad that fits entirely within a central mass zone 130 with a radius R CMZ of 0.75 inches has a smaller contribution to Iyy (and thus a larger Ixx / Iyy ratio) than a 20-gram mass pad that only partially fits within a central mass zone 130 with a radius R CMZ of 0.75 inches.

[0113] The crown mass pad 140 and / or the sole mass pad 142 can each be disposed at the center of the crown 110 and the sole 112, respectively. In many embodiments, at least a portion of the crown mass pad 140 and / or the sole mass pad 142 can intersect the YZ plane (described above as the vertical plane aligned with both the Y-axis 1050 and the Z-axis 1060). In some embodiments, the crown mass pad 140 and / or the sole mass pad 142 can be entirely located within the central 50% of the body depth D B In some embodiments, the crown mass pad 140 and / or the sole mass pad 142 can be entirely located within the central 45% of D B In some embodiments, the crown mass pad 140 and / or the sole mass pad 142 can be entirely located within the central 40% of D B In some embodiments, the crown mass pad 140 and / or the sole mass pad 142 can be entirely located within the central 35% of D B In some embodiments, the crown mass pad 140 and / or the sole mass pad 142 can be entirely located within the central 30% of D B In some embodiments, the crown mass pad 140 and / or the sole mass pad 142 can be entirely located within the central 25% of D B In some embodiments, the crown mass pad 140 and / or the sole mass pad 142 can be entirely located within the central 20% of D B In some embodiments, the crown mass pad 140 and / or the sole mass pad 142 can be entirely located within the central 50% of the body width W B In some embodiments, the crown mass pad 140 and / or the sole mass pad 142 can be entirely located within 45% of the center of W B In some embodiments, the crown mass pad 140 and / or the sole mass pad 142 can be entirely located within 40% of the center of W B In some embodiments, the crown mass pad 140 and / or the sole mass pad 142 can be entirely located within 35% of the center of W B In some embodiments, the crown mass pad 140 and / or the sole mass pad 142 can be entirely located within 30% of the center of W B In some embodiments, the crown mass pad 140 and / or the sole mass pad 142 can be entirely located within 25% of the center of W B In some embodiments, the crown mass pad 140 and / or the sole mass pad 142 can be entirely located within 20% of the center of W B In many embodiments, the foremost point of the crown mass pad 140 and / or the sole mass pad 142 can be spaced a significant proportion of the body depth D B behind the leading edge 103. In some embodiments, the foremost point of the crown mass pad 140 and / or the sole mass pad 142 can be spaced 10% or more, 15% or more, 20% or more, or 25% or more of the body depth D B behind the leading edge 103.

[0114] In many embodiments, the crown mass pad 140 and the sole mass pad 142 can comprise a significant portion of the total clubhead mass. In many embodiments, the crown mass pad 140 can be larger than the sole mass pad 142 to keep the position of the CG 160 low and / or near the line of force 125. In many embodiments, the crown mass pad 140 can have a mass between 5 and 30 grams. In some embodiments, the crown mass pad 140 can have a mass between 5 grams and 10 grams, between 10 grams and 15 grams, between 15 grams and 20 grams, between 20 grams and 25 grams, or between 25 grams and 30 grams. In some embodiments, the crown mass pad 140 can have a mass greater than 5 grams, greater than 10 grams, greater than 15 grams, greater than 20 grams, greater than 25 grams, or greater than 30 grams.

[0115] In many embodiments, the sole mass pad 142 can have a mass between 10 and 60 grams. In some embodiments, the sole mass pad 142 can have a mass between 10 grams and 15 grams, between 15 grams and 20 grams, between 20 grams and 25 grams, between 25 grams and 30 grams, between 30 grams and 35 grams, between 35 grams and 40 grams, between 40 grams and 45 grams, between 45 grams and 50 grams, between 50 grams and 55 grams, or between 55 grams and 60 grams. In some embodiments, the sole mass pad 142 can have a mass greater than 5 grams, greater than 10 grams, greater than 15 grams, greater than 20 grams, greater than 25 grams, greater than 30 grams, greater than 35 grams, greater than 40 grams, greater than 45 grams, greater than 50 grams, greater than 55 grams, or greater than 60 grams.

[0116] In many embodiments, the club head 100 can define a mass pad ratio as the mass of the sole mass pad 142 divided by the mass of the crown mass pad 140. In many embodiments, the mass pad ratio can be from 0.25 to 1.5. In some embodiments, the mass pad ratio can be between 0.25 and 0.50, between 0.50 and 0.75, between 0.75 and 1.0, between 1.0 and 1.25, or between 1.25 and 1.5. In some embodiments, the mass pad ratio can be greater than 0.25, greater than 0.50, greater than 0.75, greater than 1.0, greater than 1.25, or greater than 1.5. In some embodiments, the mass pad ratio can be less than 1.5, less than 1.4, less than 1.3, less than 1.2, less than 1.1, less than 1.0, less than 0.9, less than 0.8, less than 0.7, less than 0.6, less than 0.5, less than 0.4, less than 0.3, or less than 0.25. Although the crown mass pad 140 and the sole mass pad 142 each have a significant mass, by making the crown mass pad 140 larger than the sole mass pad 142, a club head 100 having a high Ixx / Iyy ratio and a desirable low CG160 position can be provided.

[0117] b. Weight member In addition to increasing the Ixx / Iyy ratio by distributing most of the mass of the club head near the Y'-axis 1080, Ixx and Iyy can be controlled by using one or more weight members 145. In some embodiments, the club head 100 can include at least one weight member 145 that is separately formed and attached to the body 101. The weight member 145 can be attached to any portion, either inside or outside, of the body 101. The weight member 145 can be attached to the crown 110, sole 112, heel 104, toe 106, on or near the rear end 111, near the front end 108, or any combination thereof. In many embodiments, the weight member 145 can be removably coupled to the body 101 via mechanical fastening means such as using screw fastening members or other retaining means. In other embodiments, the weight member 145 can be permanently or non-removably attached to the body 101 via welding, brazing, adhesive bonding, or any other suitable means. The weight member 145 can comprise a material having a density greater than the density of the material used to form the body 101. Thus, the weight member 145 provides a high density mass that can be positioned to impart desired mass characteristics to the club head 100. In many embodiments, the weight member 145 can be formed of a high density material such as titanium, tungsten, steel, or any suitable alloy thereof.

[0118] In some embodiments, as shown in FIGS. 9 and 10, the club head 100 can include a weight member 145 attached to the body 101 between the rear end 111 and the sole 112. The low and rearward position of the weight member 145 provides a desirable "down and back" CG position and increases the MOI of the overall club head. Since there is a large horizontal distance between the weight member 145 and both the X'-axis 1070 and the Y'-axis 1080, the very rearward position of the weight member 145 significantly contributes to both Ixx and Iyy. However, in many embodiments, the weight member 145 can be configured to contribute more to Ixx than to Iyy, thereby increasing the Ixx / Iyy ratio. To provide a high Ixx / Iyy ratio, the weight member 145 can be placed as far as possible towards the bottom of the sole 112 to maximize the contribution of the weight member to the increase in Ixx. By lowering the weight member 145 relative to the CG160, the weight member 145 is located at a position vertically away from the X'-axis 1070 but not away from the vertically extending Y'-axis 1080.

[0119] To characterize the relative contributions of the weight member 145 to Ixx and Iyy, the club head 100 can have a ratio between the weight member elevation E W and the weight member depth D W As shown in FIG. 10, the weight member elevation E W is defined as the distance between the club head CG160 and the weight member centroid 147, measured parallel to the Y'-axis 1080. The weight member depth D W is defined as the distance between the club head CG160 and the weight member centroid 147, measured parallel to the Z'-axis 1090.

[0120] In many embodiments, the club head 100 can have a ratio E W / D W between 0.30 and 0.60. In some embodiments, E W / D WThe ratio can be between 0.30 and 0.35, or between 0.35 and 0.40, 0.45 and 0.50, or between 0.55 and 0.60. In some embodiments, the club head is greater than 0.3, greater than 0.35, greater than 0.40, greater than 0.45, greater than 0.50, greater than 0.55, or greater than 0.60 E W / D W and can have a ratio. E W / D W As the ratio increases, the Ixx contribution of the weight member 145 increases relative to the Iyy contribution of the weight member 145. Thus, a substantially high E W / D W club head 100 with a ratio has an increased Ixx / Iyy ratio.

[0121] Furthermore, the MOI of the weight member 145 may be characterized by its mass relative to the total mass of the club head (referred to herein as the "mass percentage of the weight member"). The greater the proportion of the weight member 145 in the total club head mass, the greater the impact on the moment of inertia. In many embodiments, the weight member 145 may be between 10 and 30% of the total club head mass. In some embodiments, the weight member may be between 10 and 15%, or 15 and 20%, or 20 and 25%, or 25 and 30% of the total club head mass.

[0122] Together, the mass percentage of the weight member and E W / D W the ratio between the ratios can characterize how the weight member 145 contributes to an increase in the Ixx / Iyy ratio. The weight weight member 145 (high mass percentage) located near the Y'-axis 1080 substantially below the CG160 (high E W / D W ratio) results in a higher Ixx / Iyy ratio. The sum of the mass percentage of the weight member and E W / D W the ratio can be between 0.4 and 0.9. In some embodiments, the weight member mass percentage and EW / D W The sum with the ratio can be between 0.4 and 0.45, between 0.45 and 0.50, between 0.50 and 0.55, between 0.55 and 0.60, between 0.60 and 0.65, between 0.65 and 0.70, between 0.70 and 0.75, between 0.75 and 0.80, between 0.80 and 0.85, or between 0.85 and 0.90.

[0123] c. Adjustable weight member Figure 11 shows a club head 200 with an adjustable weight member 205 that can be fixed to any of a plurality of attachment points 230 within a channel 210, each attachment point being such as to promote a particular shot shape. The club head 200 can include a weight channel 210 recessed in the rear end 211 of the club head body 201, the weight channel being configured to receive the adjustable weight member 205. The adjustable weight member 205 is fixed within the weight channel 210 by mechanical fastening means such as screws 215. The weight channel 210 may be recessed within the club head 200 such that most of the adjustable weight member 205 is recessed within the weight channel 210 and does not extend beyond the periphery of the club head 200. In many embodiments, as shown in Figure 11, the weight channel 210 may have a generally curved shape following the curvature of the club head 200. The weight channel 210 may also include a plurality of straight portions angled relative to each other.

[0124] The weight channel 210 further includes a plurality of attachment points 230 for securing the adjustable weight member 205 to the weight channel 210 at discrete positions. One of the attachment points 230 may be a neutral attachment point 231 that is substantially centered in the direction from the heel to the toe of the club head 200. The neutral attachment point 231 promotes a generally straight ball flight. The club head 200 can further include a heel side attachment point 232 located on the heel side of the neutral attachment point 231. The heel side attachment point 232 positions the adjustable weight member 205 closer to the heel 204 of the club head 200, thereby moving the CG260 towards the heel side and promoting a draw type golf shot. The club head 200 can further include a toe side attachment point 233 located on the toe side of the neutral attachment point 231. The toe side attachment point 233 positions the adjustable weight member 205 closer to the toe of the club head 200, thereby moving the CG260 towards the toe side and promoting a fade type golf shot.

[0125] In many embodiments, the weight member 205 may have a mass in the range of 1 g to 40 g. In some embodiments, the mass of the weight member 1090 is in the range of 1 g to 5 g, 5 g to 10 g, 10 g to 15 g, 15 g to 20 g, 20 g to 25 g, 25 g to 30 g, 30 g to 35 g, or 35 g to 40 g.

[0126] Placing the weight member 205 at the rear end 211 of the club head 200 while having mounting points 230 that are relatively close to each other means that when the mass of the weight member 205 is selected to be at the lower limit of its range (e.g., 5 g), the weight member 205 makes a relatively small contribution to the CG and MOI of the club head 200. Selecting a heavier weight member 205 with a mass at the upper limit of that range (e.g., 40 g) results in the weight member having a relatively large contribution to the CG and MOI of the club head 200 while still having a relatively small distance between the mounting points 230. In this way, the design of the adjustable weight member 205 enables the weight channel 210 to remain compact while providing significant shot shaping capabilities. A further advantage of the compact weight channel 210 is that the structure of the weight channel 210 can be made lightweight, leaving additional mass available for placement in other locations of the club head 200.

[0127] d. Multi - Material Structure In some embodiments, as illustrated in FIGS. 12 - 14, the club head 300 can comprise a multi - material structure. In such embodiments, the body 301 can comprise at least a first component 350 formed of a metallic material and a second component 352 formed of a non - metallic material such as a composite material. The non - metallic second component 352 can form at least a part of the crown 310, at least a part of the heel 304, at least a part of the toe 306, at least a part of the sole 312, or any combination thereof. Providing the body 301 of the club head 300 that is at least partially formed by the non - metallic component 352 can create discretionary mass that can be redistributed throughout the club head 300 to increase the Ixx / Iyy ratio. By providing at least a part of the body 301 formed by the non - metallic second component 352, the extra discretionary mass can be placed within the central mass zone 330 or used to increase the mass of the mass pads or weight members described above.

[0128] As shown in FIG. 12, in many embodiments, the club head 300 can include a non-metallic second component 352 that forms a majority of the surface of the crown 310. In the illustrated embodiment, the body 301 includes a first component 350 that forms the front portion of the crown 310 in the vicinity of the hitting face 302. The second component 352 can form the remaining portion of the crown. In the illustrated embodiment, the second component 352 can form a "wrap around" design that wraps around the heel 304 and toe 306 and extends onto the sole 312 (as shown in FIG. 14). In many embodiments, the second component 352 does not wrap onto the trailing edge 309 of the club head 300.

[0129] As shown in FIG. 12, the second component 352 has a second component trailing edge 356 that contacts the boundary within the periphery of the crown 310, does not extend beyond the club head trailing edge 309, or extend onto the sole 312. In many embodiments, as shown by FIG. 12, the second component trailing edge 356 can be located substantially near the club head trailing edge 309. In other embodiments, referring to FIG. 13, the second component trailing edge 356 can be substantially spaced from the club head trailing edge 309. In the illustrated embodiment of FIG. 13, the first component 350 forms a rear lip 359 that extends forward from the club head trailing edge 309 and forms a rear portion of the crown 310. The second component 352 can include a notch 357 corresponding to the shape of the rear lip 359 such that the second component trailing edge 356 contacts the leading edge of the rear lip 359. This configuration positions the rear connection between the first component 350 and the second component 352 away from the club head trailing edge 309. Often, doing so can provide sufficient space between the non-metallic second component 352 and a weight insert 345 near the club head trailing edge (as shown in FIG. 14), providing both manufacturing and durability advantages. Manufacturers often require significant clearance between such rear weight members 345 and non-metallic components to enable casting the shape of the weight member support structure.

[0130] Referring to FIG. 14, the second component 352 wraps around the heel 304 and the toe 306 and forms part of the sole 312. The second component 352 can include a second component heel portion 353 that forms at least a part of the sole 312 near the heel 304 and a second component toe portion 354 that forms at least a part of the sole 312. In the illustrated embodiment, the first component 350 forms most of the sole 312. As described above, the club head 300 can include a weight member 345 disposed on the sole 312 near the trailing edge 309 of the club head to provide a down and back CG 360 position and increase the MOI.

[0131] The amount of non-metallic material forming the body 301 may be characterized by the percentage of the surface area of the crown 310 formed by the second component 352 and / or the percentage of the surface area of the sole 312 formed by the second component 352. In some embodiments, the second component 352 may form at least 50% of the surface area of the crown 310. In some embodiments, the second component 352 may form at least 60%, at least 70%, at least 80%, or at least 90% of the surface area of the crown 310. In some embodiments, the second component 352 may form at least 10% of the surface area of the sole 312. In some embodiments, the second component 352 may form at least 15%, at least 20%, at least 25%, or at least 30% of the surface area of the sole 312. Summing the percentages of the sole and crown that are composite defines the composite percentage of the sole and crown. The higher the percentage of the body 301 formed by the non-metallic second component 352, the more discretionary mass that can be strategically distributed to increase the Ixx / Iyy ratio.

[0132] The wrap-around design of the non-metallic second component 352 can assist in dispersing the mass within the central mass zone 130 and provide a higher Ixx / Iyy ratio. In many embodiments, the second component heel portion 353 and the second component toe portion 354 may form only a portion of the sole 312 that is located near the periphery of the club head and outside of the central mass zone 130. In many embodiments, the second component heel portion 353 and the second component toe portion 354 may not extend into the central mass zone 130 having a radius R of 0.75 inches. This configuration removes mass from the portion of the sole 312 that is outside of the central mass zone 130 without removing mass from the proportion of the sole within the central mass zone 130. The discretionary mass created by removing mass from the sole 312 can be redistributed within the central mass zone 130 to increase the Ixx / Iyy ratio. CMZ This configuration removes mass from the portion of the sole 312 that is outside of the central mass zone 130 without removing mass from the proportion of the sole within the central mass zone 130. The discretionary mass created by removing mass from the sole 312 can be redistributed within the central mass zone 130 to increase the Ixx / Iyy ratio.

[0133] e. Lightweight Shaft Receiver Structure In some embodiments, referring to FIG. 24, the club head 400 can include a lightweight shaft receiver structure 478 that creates discretionary mass. The discretionary mass can be allocated to portions of the club head 400 that increase the Ixx / Iyy ratio. By providing the lightweight shaft receiver structure 478, the extra discretionary mass can be placed within the central mass zone 430 or used to increase the mass of the mass pads or weight members described above.

[0134] Referring to FIG. 24, in some embodiments, the club head 400 can include an adjustable shaft receiving mechanism. The adjustable shaft receiving mechanism may be used to adjust the loft angle and / or lie angle for a particular player. The adjustable shaft receiving mechanism can be similar to those described in U.S. Patent Application No. 15 / 003,494, filed Jan. 21, 2016 (now U.S. Patent No. 9,868,035, issued Jan. 16, 2018); and U.S. Patent Application No. 17 / 304,836, filed Jan. 25, 2021 (now U.S. Patent No. 11,607,590, issued Mar. 21, 2023), both of which are hereby incorporated by reference in their entirety.

[0135] The adjustable shaft receiving mechanism is configured to receive a golf club shaft (not shown) and includes a shaft sleeve 480 that is retained within the hosel 405 by a fastener 482. The shaft sleeve 480 and the hosel 405 have corresponding shapes that allow the shaft sleeve 480 to be removably rotated into a plurality of different configurations. By rotating the shaft sleeve 480 between different configurations, it is possible to provide adjustability of the loft angle 10 and / or the lie angle 15 to the club head 400. Referring to FIG. 24, the lightweight shaft receiving structure 478 houses the shaft sleeve 480 with a minimal structural mass. At least a portion of the shaft sleeve 480 is exposed within the internal cavity 407. In this embodiment, the shaft sleeve 480 is not retained by an internal structure such as an internal hosel tube or hosel wall, but rather is retained to the club head 400 by a structure that also forms at least a portion of the exterior of the club head body 401. In other words, the shaft sleeve 480 is primarily supported and retained by a portion of the body 401. In many embodiments, the shaft receiving structure 478 has an upper end and a lower end. In this embodiment, the shaft sleeve 480 is fixed only at the upper end 488 and the lower end 489. The shaft sleeve 480 is inserted through the hosel bore opening 484 and retained at the upper end by the hosel wall 486. The shaft sleeve 480 can be fixed to the club head 400 using a fastener 482.

[0136] The lightweight shaft receiver structure 478 can produce a discretionary mass of from 3 grams to 12 grams as compared to prior art shaft receiver structures where the shaft sleeve is hidden from an internal cavity by a support structure such as a hosel tube or the inner wall of a hosel. In some embodiments, the lightweight shaft receiver structure 478 can produce a discretionary mass of between 3 grams and 5 grams, between 4 grams and 6 grams, between 5 grams and 7 grams, between 6 grams and 8 grams, between 7 grams and 9 grams, between 8 grams and 10 grams, between 9 grams and 11 grams, or between 10 grams and 12 grams as compared to prior art shaft receiver structures. In some embodiments, the lightweight shaft receiver structure 478 can produce a discretionary mass of more than 3 grams, more than 4 grams, more than 5 grams, more than 6 grams, more than 7 grams, more than 8 grams, more than 9 grams, or more than 10 grams as compared to prior art shaft receiver structures. Reducing the mass of the shaft receiver structure 478 by eliminating redundant support structures can free up discretionary mass that can be reallocated to other areas of the clubhead 400 to increase the Ixx / Iyy ratio. In particular, since the shaft receiver structure 478 is located near the heel 404, the mass forming the shaft receiver structure is typically located outside of the central mass zone 430. Reducing the mass of the shaft receiver structure 478 by eliminating redundant support structures is particularly effective in increasing the Ixx / Iyy because doing so removes mass located outside of the central mass zone 430 and can redistribute the mass within the central mass zone 430.

[0137] IV. Optimization of Bulges and Rolls As described above, the club head 100 can further include a bulge curvature and a roll curvature that are specially adjusted according to the club head characteristics to enhance performance and forgiveness. Thus, the club head can satisfy the relationship of one or more bulge radii or roll radii in order to maximize carry distance and forgiveness. The relationship of the bulge radius and the roll radius can depend on factors such as the CG position, the MOI, and the coefficient of restitution (COR). The optimized bulge curvature and roll curvature can be particularly useful in low-MOI club heads because the increased forgiveness provided by the bulge curvature and roll curvature can compensate for the loss of forgiveness associated with a low target Iyy. In some embodiments, as will be apparent in the following examples, providing a low-MOI club head 100 with optimized bulge and roll radii can provide increased forgiveness compared to a high-MOI club head with standard bulge and roll radii (i.e., bulge and roll radii that are not optimized considering the characteristics of the club head).

[0138] The striking face 102 of the club head 100 has a bulge radius that provides forgiveness for off-center hits on the toe side and the heel side. When the golf ball is mis-hit near the heel 104 or the toe 106, the club head 100 rotates about the Y'-axis 1080. Rotation about the Y'-axis 1080 creates a gear effect between the striking face 102 and the golf ball, imparting side spin to the golf ball. In an off-center hit on the toe side, the gear side spin causes the golf ball to draw from the toe side towards the heel side. Conversely, in an off-center hit towards the heel, the gear-like side spin fades the golf ball from the heel direction towards the toe direction. The bulge curvature cancels the effect of the gear side spin by 1) changing the starting direction of the golf shot and 2) changing the severity of the gear effect. For example, making the bulge radius tight causes the golf ball to start more offline and the gear effect to decrease, while making the bulge radius flat causes the golf ball to start closer to the center and the gear effect to increase.

[0139] The positions of Iyy and CG of the club head affect the amount of rotation at impact and the gear effect on heel or toe mis-hits, respectively. Therefore, each must be considered to determine the optimal bulge radius. The smaller the Iyy, the greater the tendency for the club head to twist from heel to toe, and the greater the gear side spin. Also, a more rearward CG position increases the rotation of the club head from heel to toe at a mis-hit away from the geometric center 120. The club head 100 has a bulge radius that appropriately considers the Iyy and CG positions. The optimal bulge radius balances the starting line and the gear effect and provides an appropriate amount of side spin to return the golf ball to the target line. Further, the coefficient of restitution (hereinafter "COR") of the club head can play a role in determining the optimal bulge radius. A club head with a low COR has a reduced ball speed at a mis-hit. In such a low COR club head, it may be desirable to provide a flatter bulge radius. A flatter bulge radius reduces the oblique impact between the striking face 102 and the golf ball at a heel or toe mis-hit, thereby better retaining the ball speed. In a high COR club head, since the high COR naturally retains the ball speed at a mis-hit, the bulge radius may be made tighter to prioritize gear spin correction over ball speed retention.

[0140] In many embodiments, the bulge radius can be determined by computer simulation considering the range or values of the MOI (both Ixx and Iyy) and the CG position of the club head. In many embodiments, the computer simulation can be performed over various swing speeds, face delivery angles, and / or impact positions on the striking face 102. In many embodiments, an Ixx range and an Iyy range can be selected, and the bulge radius can be calculated as a function of the CG position of the club head 100 within the Ixx range and the Iyy range. In some embodiments, the club head 100 has an Iyy of 2000 g*cm 2 to 3200 g*cm2 within the range, and when Ixx is from 1480 g·cm 2 to 2370 g·cm 2 the relational expression 1 is satisfied.

Equation

[0141] Furthermore, the striking face 102 of the club head 100 has a roll radius that provides tolerance for mishits in the crown and sole directions. When the golf ball is mishit near the crown 110 or the sole 112, the club head 100 rotates about the X'-axis 1080. Rotation about the X'-axis 1070 creates a gear effect between the striking face 102 and the golf ball, changing the natural backspin of the golf ball. In the case of a mishit in the crown direction, the gear effect reduces the backspin of the golf ball. Conversely, in the case of a mishit on the sole side, the gear effect increases the backspin of the golf ball. The roll curvature cancels out the gear effect on the backspin by 1) changing the launch angle of the golf shot and 2) changing the severity of the gear effect. For example, making the roll radius tighter causes the golf ball to be launched higher in the case of a mishit in the crown direction and lower in the case of a mishit in the sole direction, reducing the gear effect, and making the roll radius flatter causes the golf ball to be launched closer to the launch angle in the case of a center strike, increasing the gear effect.

[0142] The Ixx and CG positions of the club head affect the amount of rotation at impact and the gear effect for mishits in the crown and sole directions, respectively. Therefore, both must be considered to determine the optimal roll radius. The lower the Ixx, the greater the tendency for the club head to twist about the X'-axis 1070 and the greater the gear effect on the backspin. Also, a more rearward CG position increases the rotation of the club head about the X'-axis 1070 during a mishit away from the geometric center 120. The club head 100 has a roll radius that appropriately considers the Ixx and CG positions. The optimal roll radius balances the launch angle and the gear effect, provides the correct combination of launch angle and backspin rate, and maximizes the carry distance of the golf shot.

[0143] For example, in the case of a mishit in the sole direction, due to the gear effect, the backspin of the golf ball increases, the ball is lifted high in the air, and it may fly high but not far. The roll radius corrects this increase in backspin by lowering the launch angle during a mishit in the sole direction. Generally, the lower Ixx is, the greater the gear effect during a mishit in the sole direction. To more aggressively lower the launch angle, a tighter roll radius is desired. In the case of a mishit in the crown direction, due to the gear effect, the backspin of the golf ball increases, the lift and hang time of the golf ball are hindered, and the flight distance decreases. The roll radius compensates for this decrease in backspin by increasing the launch angle during a mishit in the crown direction, causing the trajectory of the golf ball to fly farther.

[0144] The club head COR can also be involved in optimizing the roll radius for the same reasons as described above. A flatter roll radius reduces the oblique impact between the striking face 102 and the golf ball during a mishit in the crown or sole direction, thereby better maintaining the ball speed. In a high COR club head, since the high COR naturally maintains the ball speed during a mishit, the roll radius can be made tighter in order to prioritize the launch angle and backspin rate over maintaining the ball speed.

[0145] In many embodiments, the roll radius can be determined by computer simulation considering the range or values of the MOI (both Ixx and Iyy) and CG position of the club head. In many embodiments, the computer simulation can be performed over various swing speeds, face delivery angles, and / or impact positions on the striking face 102. In many embodiments, an Ixx range and an Iyy range can be selected, and the roll radius can be calculated as a function of the CG position of the club head 100 within the Ixx range and the Iyy range. In some embodiments, the club head 100 has an Iyy in the range of 2000 g*cm 2 to 3200 g*cm 2 and 1480 g*cm2 from 2370 g*cm 2 satisfies relational expression 2 for Ixx in the range of

Equation

[0146] For example, in many embodiments, the club head 100 satisfies relational expression 2 and has an Iyy less than 3500 g*cm 2 less than 3200 g*cm 2 less than 3000 g*cm 2 less than 2800 g*cm 2 less than, or less than 2600 g*cm 2 For example, in many embodiments, the club head 100 satisfies relational expression 2 and has an Ixx less than 2600 g*cm 2 less than 2500 g*cm 2 less than 2400 g*cm 2 less than 2200 g*cm 2 less than 2000 g*cm 2 less than 1800 g*cm 2 less than, or less than 1500 g*cm 2 less than can be had.

[0147] The above relational expressions 1 and 2 can be used to determine the bulge radius and the roll radius independently of each other. However, for a specific club head 100, the bulge radius and the roll radius must be complementary to each other. The results of the computer simulation described above were further utilized to determine the bulge radius and the roll radius of the club head in consideration of each other. Therefore, in some embodiments, the club head 100 satisfies relational expressions 3 and / or relational expression 4 for Iyy between 2000 g*cm 2 and 3200 g*cm 2 and for Ixx between 1480 g*cm 2 and 2370 g*cm 2 2

Equation

Equation

[0148] For example, in many embodiments, the club head 100 can satisfy relationships 3 and 4, and be less than 3500 g*cm 2 less than 3200 g*cm 2 less than 3000 g*cm 2 less than 2800 g*cm 2 less than 2600 g*cm 2 less than 2500 g*cm 2 less than 2400 g*cm 2 less than 2200 g*cm 2 less than 2000 g*cm 2 less than 1800 g*cm 2 less than, or have an Iyy less than 1500 g*cm 2 In many embodiments, the club head 100 can have an Iyy between 2000 g*cm 2 and 3200 g*cm 2 and an Ixx between 1480 g*cm 2 and 2370 g*cm 2 The club head 100 can satisfy any one or a combination of relationships 1, 2, 3, or 4 in order to generate an optimized bulge curvature and roll curvature based on the characteristics of the club head 100.

[0149] As described above, many of the club head embodiments described in this document are targeted at low Iyy goals. Generally, the optimized bulge curvature and roll curvature for a low MOI club head can be substantially tighter than the bulge curvature and roll curvature for a high MOI club head. In many embodiments described herein, the club head 100 can have an Iyy goal between 2000 g*cm 2 and 3200 g*cm 2の and a bulge radius between 5 inches and 11 inches. In some embodiments, the club head 100 can have an Iyy between 2000 g*cm 2 and 3200 g*cm 2It can have a target Iyy between that and a bulge radius less than 11 inches, less than 10.5 inches, less than 10 inches, less than 9.5 inches, less than 9.0 inches, less than 8.5 inches, less than 8.0 inches, less than 7.5 inches, less than 7.0 inches, less than 6.5 inches, less than 6.0 inches, less than 5.5 inches, or less than 5.0 inches. In some embodiments, the club head 100 is 2000 g*cm 2 and 3200 g*cm 2 It can have a target Iyy between that and a roll radius between 4 inches and 9 inches. In some embodiments, the club head 100 is 2000 g*cm 2 and 3200 g*cm 2 It can have a target Iyy between that and a roll radius less than 9.0 inches, less than 8.5 inches, less than 8.0 inches, less than 7.5 inches, less than 7.0 inches, less than 6.5 inches, less than 6.0 inches, less than 5.5 inches, less than 5.0 inches, or less than 4.5 inches, less than 4.0 inches. In many embodiments, the club head 100 has a bulge radius and / or a roll radius that is significantly lower than that of prior art club heads. Conventionally, for prior art driver type club heads, the bulge radius and the roll radius are each about 12 inches and typically in the range of 10 to 14 inches.

[0150] The optimized bulge curvature and roll curvature can be applied to the striking face 102 of the club head 100 having any one or combination of the above features. In particular, in many embodiments, the optimized bulge curvature and roll curvature are applied to the club head 100 having a body shape like a cube and a large proportion of the mass distributed near the X' axis (i.e., a large percentage of the total club head mass distributed within the small central mass zone 130). In such embodiments, the club head 100 has a high Ixx / Iyy ratio and, in combination with the optimized bulge curvature and roll curvature, provides maximum performance within the context of a particular Iyy target.

[0151] V. Adjustable Swing Weight System In some embodiments, referring to FIGS. 15 - 22, the club head may include an adjustable swing weight system that enables the manufacture of several club heads with different swing weights, all with a consistent Iyy target. The adjustable swing weight system is replaceable and / or removable and provides a plurality of weight inserts, each providing a consistent contribution to Iyy. "Swing weight" refers to the process of building up the club head to a particular total mass to suit the needs of a particular player. For example, one particular player may be suited to a larger club head total mass, while another player may be suited to a club head with a lesser total mass. Generally, the desired swing weight is achieved by adding one or more replaceable and / or removable weight inserts of different masses to the club head. However, by doing so, the mass characteristics of the club head (including Iyy) will vary from one manufacture to another. The adjustable swing weight system described herein enables the manufacture of multiple club heads of different masses with little or no change to club head Iyy. Such an adjustable swing weight system is useful when a designer wishes to achieve a target Iyy for the manufacture of all club heads while allowing for different swing weights.

[0152] The adjustable swing weight system described herein includes a plurality of weight inserts, and at least one of the plurality of weight inserts may be selected to be coupled to the club head to adjust the swing weight. The plurality of weight inserts, when inserted into the club head, may be designed such that each of the plurality of weight inserts results in a club head construction having substantially the same club head Iyy value, but substantially different club head masses. In particular, the adjustable swing weight system described in further detail below allows for a variation in club head mass of more than 26 grams with very little (or zero) variation in club head Iyy. In some embodiments, the adjustable swing weight system can allow for a variation between club head constructions of 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, or more than 25 grams. In some embodiments, the adjustable swing weight system provides a variation in Iyy between constructions of less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2%, less than 1%, or about 0%.

[0153] To provide a plurality of club head constructions with different swing weights while maintaining Iyy constant, the adjustable swing weight system described herein includes a plurality of replaceable and / or removable weight inserts of different masses. Each of the plurality of replaceable and / or removable weight inserts can be positioned within the club head such that each weight insert has the same contribution to Iyy. The relationship between the mass, position, and Iyy contribution of the weight inserts is described in detail below.

[0154] Considering relationship 2 (defined in the above definition section), treating the weight insert as a point mass of mass m and offsetting it by a perpendicular distance r (hereinafter also referred to as O w ), the Iyy contribution of each weight insert can be determined. When the Iyy contributions of the weight inserts are equal in the build, a consistent Iyy target may be achieved for all available clubhead builds. There are two ways to obtain the same Iyy contribution from all weight inserts. 1) As the mass of the weight insert increases in the build, the offset of the weight insert CG from the Y' axis 1080 decreases quadratically, or 2) the offset of the weight insert from the Y' axis 1080 is made negligible or zero (i.e., the weight insert CG is located at the clubhead CG). In the first method, the mr 2 value of the weight insert with respect to the Y' axis 1080 is held constant in the build, but in the second method, mr 2 is set equal to 0 for all builds. The various embodiments described in detail below identify clubhead designs that enable weight insert configurations with substantially the same Iyy contribution.

[0155] Figures 15 through 17C show a two-piece club head 1500 configured with a tubular recess 1585 for receiving any one of a plurality of weight inserts 1595 of an adjustable swing weight system. The plurality of weight inserts 1595 can have different masses and different positions of the weight insert centers of gravity 1599 that provide a consistent contribution to Iyy. Referring to FIG. 15, the club head 1500 can include two bodies, a front portion 1522 and a rear portion 1523. The front portion 1522 and the rear portion 1523 are permanently joined by a method such as welding or adhesive bonding to form the club head 1500. In some embodiments, the front portion 1522 and the rear portion 1523 can be separate components formed of different materials. In many embodiments, the rear portion 1523 can be a lightweight non-metallic material, while the front portion 1522 can be a metallic material. In other embodiments, both the front portion 1522 and the rear portion 1523 can be formed of metallic materials.

[0156] The front portion 1522 is configured as a generally hollow concave structure that forms an internal cavity 1507 of the club head 1500. The rear portion 1523 can have a generally solid structure with a through hole that forms a tubular recess 1585. The tubular recess 1585 can extend from the sole 1512 or the rear end 1511 of the club head 1500 to the internal cavity 1507. The tubular recess 1585 is configured to receive a weight insert 1595 corresponding to the club head construction. The weight insert 1595 is locked in a predetermined position within the tubular recess 1585 by implementing any combination or one of various retaining mechanisms. The retaining mechanism may include screw engagement, locking via a strut, fixing by a pin, or any other non-permanent retaining mechanism known in the art. The tubular recess 1585 is surrounded by a cylindrical shell 1588. The cylindrical shell 1588 is a generally cylindrical barrier that separates the tubular recess 1585 from the internal cavity 1507 of the club head 1500. In some embodiments, once the weight insert 1595 is locked in a predetermined position within the tubular recess 1585, the cylindrical shell 1588 may be capped to seal the tubular recess 1585. The cylindrical shell 1588 can be permanently or non-permanently sealed using a cap, a plug, or various other methods known in the art. The club head 1500 further includes a support member 1566 that connects the cylindrical shell 1588 to the sole 1512 of the club head 1500. The tubular recess 1585 further includes a tube axis 1586 that extends through the center of the cylindrical shell 1588 and runs along the length of the tubular recess 1585, as shown in FIG. 15. The tubular recess 1585 is arranged such that the tube axis 1586 is aligned with the line of force 1525 of the club head 1500. By aligning the tube axis 1586 with the line of force 1525 of the club head 1500, the hitting conditions are consistent among builds regardless of which weight insert 1595 is received in the tubular recess 1585.

[0157] As described above, the weight inserts 1595 each have a unique weight insert center of gravity 1599 (hereinafter, "CG" wi") position and each weight insert 1595 is designed to accommodate a unique club head construction. Different CGs wi The position of 1599 can be provided by varying any combination of the size, shape, or density of each of the plurality of weight inserts 1595. In the illustrated embodiment, each of the plurality of weight inserts 1595 has the same dimensions and generally comprises a cylindrical shape. However, in other embodiments, the weight inserts 1595 can have different dimensions and can be of any shape including trapezoidal, elliptical, conical, cubic, or hexagonal. In the present embodiment, different CGs wi are provided by varying the density of the weight insert 1595 along the length 1596 of the weight insert (hereinafter, "L wi "). In some embodiments, the weight insert 1595 can be made of a composite material having a density that varies along L wi 1596. Alternative embodiments can vary the position of the CG wi 1599 by other means. For example, in some embodiments, the weight insert 1595 can comprise a hollow core and, along the length of this core, a plurality of weights of different discrete weights or masses can be arranged to provide a particular CG wi 1599 position. In some embodiments, the position of the CG wi 1599 can be manipulated by forming a weight insert 1595 comprising a plurality of materials or composite materials. In the present embodiment, the density of the weight insert 1595 need not vary along the weight insert width 1597 (or W wi ) or the weight insert height 1598 (or H wi ). By varying the density of the different weight inserts 1595 along each respective length L wi , as shown in FIG. 16, the CG wi 1599 can be moved to any position along the length L wi . The position of the unique CG wi 1599 between the weight inserts 1595 is the weight offset between the builds (hereinafter, "OW」 ) to allow for variation. O W is defined as the distance between the CG1560 of the club head 1500 measured perpendicular to the Y'-axis 1080 and the CG wi 1599, and is interchangeable with the term "r" in Equation 2. When all the weight inserts 1595 are attached at the same position as in the current embodiment, by designing the plurality of weight inserts 1595 to their respective CG wi 1599 positions, each weight insert 1595 can have its own O W It becomes possible to have.

[0158] Figure 16 shows a plurality of weight inserts 1592, 1593, 1594 each having its own CG wi positions. The adjustable swing weight system described herein comprises a plurality of cylindrical weight inserts configured according to the embodiment of FIG. 15. Referring to FIG. 16, the plurality of weight inserts 1595 are, as described above, two or more weight inserts 1595 each having its own CG wi 1599 position and its own mass. This example comprises a lightweight weight insert 1592, a medium-weight weight insert 1593, and a heavyweight weight insert 1594. The three weight inserts 1592, 1593, 1594 of this embodiment are of the same size and shape, but have different masses and CG wihas a position. In other embodiments, the plurality of weight inserts 1595 can comprise any number of weight inserts, such as 2 weight inserts, 3 weight inserts, 4 weight inserts, 5 weight inserts, 6 weight inserts, 7 weight inserts, 8 weight inserts, 9 weight inserts, 10 weight inserts, 11 weight inserts, 12 weight inserts, 13 weight inserts, 14 weight inserts, 15 weight inserts, 16 weight inserts, 17 weight inserts, 18 weight inserts, 19 weight inserts, or 20 weight inserts.

[0159] Figures 17A, 17B, and 17C show how each of the plurality of weight inserts 1595 can be received by the club head 1500 such that each has a unique O w value. The weight inserts 1595 of the present embodiment are offset a distance O that increases quadratically as the mass of the weight insert decreases in order to achieve the same contribution to Iyy. For example, as shown in FIG. 17A, the lightweight weight insert 1592 has a greater O W than the medium weight insert 1593 (shown in FIG. 17B) or the heavy weight insert 1594 (shown in FIG. 17C). The offset of the lightweight weight insert 1592 along the Y'-axis 1080 by a distance O W results in an Iyy value of the club head 1500 that is greater than the Iyy value of the club head 1500 when the weight insert 1595 is not received by the tubular recess 1585. The medium weight insert 1593 of FIG. 17B has an O W that is less than the offset of the lightweight weight insert 1592, and the heavy weight insert 1594 of FIG. 17C has an O wis smaller than that of the lightweight weight insert 1592, and the Iyy contribution is the same as that of the lightweight weight insert 1592. The same Iyy contribution of the medium-weight weight insert 1593 and the lightweight weight insert 1592 decreases quadratically in proportion to the increase in mass between the medium-weight weight insert 1593 and the lightweight weight insert 1592 O W is achieved by providing. Finally, in this example, the weight insert 1594 in FIG. 17C is smaller than both the lightweight weight insert 1592 and the medium-weight weight insert 1593 O W and has. The mass of the weight insert 1594 is also such that it provides the same Iyy contribution as the lightweight weight insert 1592 and the medium-weight weight insert 1593. The same Iyy contribution of the weight insert decreases quadratically in proportion to the increase in mass between the weight insert 1594 and the lightweight weight insert 1592 O W is achieved by providing to the weight insert 1594.

[0160] The adjustable swing weight system described above allows the swing weight of the club head to be changed while suppressing the variation of the club head Iyy to a negligible extent (or zero). Further, in many embodiments, each of the weight inserts 1595 has its CG wi 1599 positioned such that it is at least partially inserted into the club head 1500 along the line of force 1525 of the club head 1500. Providing the CG wi 1599 along the line of force 1525 ensures consistent launch characteristics in the club head because the relative distance between the CG 1560 of the club head and the line of force 1525 remains consistent in the cavity.

[0161] Figures 18 through 20 show an alternative embodiment of the club head 1600 of an adjustable swing weight system. This embodiment includes all the same features of the adjustable swing weight system of FIGS. 15 through 17C, but with an alternative design for the weight insert 1695. The club head 1600 includes an adjustable swing weight system with a plurality of weight inserts 1695, and at least one of the plurality of weight inserts 1695 may be selected to be at least partially inserted into the club head 1600 at different positions to adjust the swing weight of the club head 1600. The embodiments of FIGS. 18 through 20 utilize the fact that the weight insert 1695 can be treated as a point mass. In particular, since the weight insert 1695 can be treated as a point mass according to Equation 2, it is not necessary to keep the shape and size of the weight insert 1695 constant. Thus, instead of having weight inserts 1695 of the same size and shape, the weight inserts 1695 of the club head 1600 can be cylindrical weights of different dimensions. By varying the dimensions of the weight inserts 1695 for different club head structures, a difference in the mass of the weight inserts 1695 can be created. In order to achieve a constant Iyy of the club head 1600 when any of the plurality of weight inserts 1695 is at least partially inserted into the club head 1600, all of the weight inserts 1695 are different O WIt is fixed at different discrete positions within the tubular recess 1685 corresponding to the values. Similar to the embodiments shown in FIGS. 17A, 17B, and 17C, the different discrete positions of the weight insert 1695 allow the weight of the club head 1600 to be varied while maintaining substantially the same Iyy value of the club head 1600. As described above, a consistent Iyy contribution from a plurality of weight inserts having different masses can be achieved by placing the weight inserts near or directly at the club head CG position. A further alternative embodiment of the adjustable swing weight system is shown in FIG. 21. This alternative embodiment includes all the same features of the adjustable swing weight system described above and introduces an alternative design of the tubular recess 1785. The tubular recess 1785 is a recess extending from the rear portion 1711 of the club head 1700. The tubular recess 1785 is surrounded by a cylindrical shell 1788. The cylindrical shell 1788 is a generally thin-walled cylindrical barrier that separates the tubular recess 1785 from the internal cavity 1707 of the club head 1700. The club head 1700 further includes a support member 1766 that connects the cylindrical shell 1788 to the sole 1712 of the club head 1700. Any of a plurality of weight inserts 1795 may be inserted into the tubular recess 1785, and CG wi 1799 is configured to be locked in a predetermined position when aligned with the CG 1760 of the club head 1700. CG wi 1799 is, O w aligned with the CG 1760 of the club head 1700 such that it can be ignored or zero for all builds. CG wi By aligning 1799 with the CG 1760 of the club head 1700, all of the plurality of weight inserts 1795 become such that their contribution to the Iyy of the club head 1700 is zero or negligible, and thus, an Iyy of the club head 1700 that is substantially the same for all builds is obtained. Substantially zero O WBy providing a value, regardless of the mass of the weight insert 1795, the contribution of the weight insert 1795 to Iyy is substantially zero. This embodiment enables the total club head mass to vary greatly within the build margin while suppressing the variation of Iyy to an ignorable extent. In this embodiment, as long as each of the plurality of weight inserts has a zero or negligible O W value, the weight insert 1795 may be composed of various materials, shapes, or sizes.

[0162] Another embodiment of the adjustable swing weight system is shown in FIG. 22. The adjustable swing weight system of FIG. 22 is the same as the embodiment of FIG. 21 except that the tubular recess 1885 extends from the sole 1812 of the club head 1800. In this embodiment, any of the plurality of weight inserts 1895 may be inserted into the tubular recess 1885, and the CG wi 1899 is configured to be aligned with the CG 1860 of the club head 1800. The club head 1800 further includes a support member 1866 that provides support to the bottom of the cylindrical shell 1888. In many embodiments, the support member 1866 can take the form of a mass pad similar to the sole mass pad described above.

[0163] VI. Additional Features The various embodiments of the club head described herein that include a high Ixx / Iyy ratio, optimized bulge and roll curvatures, and / or an adjustable swing weight system can include one or more additional features that provide performance improvements. The various features described below can be provided in any combination and can be applied to the club head described in any of the various embodiments above.

[0164] a. Internal Ribs In many embodiments, as shown in FIG. 23, the club head 800 can include a plurality of ribs disposed on the inner surface of the body 801 and configured to dampen vibrations and / or structurally reinforce a portion of the club head 800. Generally, the sound and feel response of a golf club head is highly dependent on the body shaping of the club head. The cube-like body shaping of the club heads described herein can, in some cases, introduce dominant vibrations upon impact, resulting in a harsh sound or feel upon impact. The ribs can be provided to dampen the dominant vibrations and provide a more desirable, subdued sound and feel response.

[0165] In various embodiments, the club head 800 can include any number of ribs, and any one or more of the plurality of ribs can extend along the inner surface of the sole 812, crown 810, skirt 814, or any combination thereof. In the illustrated embodiment of FIG. 23, the club head 800 includes a pair of central ribs 835 that extend across a majority of the inner surface 821 of the sole. Each of the central ribs 835 extends obliquely across the inner surface 821 of the sole, from substantially near the heel 804 to substantially near the toe 806. In many embodiments, the central ribs 835 can be substantially parallel to each other. The central ribs provide a damping effect across a majority of the sole 812, which is an area where dominant vibrations tend to occur. The club head 800 further includes a pair of rear ribs 836 located near the rear end 811 and extending substantially in a front-to-back direction. The rear ribs 836 can be particularly useful in embodiments that include a weight member (such as those described above) coupled to the lower and rear portion of the body 801. In such embodiments, the rear ribs 836 are effective in dampening the vibrations created by providing a weight member in the rear portion of the club head 800. The club head 800 of the illustrated embodiment further includes a sole mass pad 840, as described in detail above. One or more of the central ribs 835 and / or rear ribs 836 can contact or intersect the sole mass pad 840.

[0166] Vibration control in the design of a golf club head highly depends on local reinforcement of the high vibration region. Thus, either the central rib 835 and / or the rear rib 836 can be provided at any position or direction, such as in the heel-to-toe direction, from the front to the back, diagonal direction, or any combination thereof. As described above, the rib provides vibration control to compensate for any dominant vibrations related to the unique body shape and mass distribution of the club head described in this specification. With the rib, it is possible to achieve a club head that provides a desirable sound and feel response while achieving a high Ixx / Iyy ratio.

[0167] b. Aerodynamic characteristics As described above, the club head may include several features for maximizing aerodynamic characteristics while maintaining a balance of the Ixx / Iyy ratio. Specifically, the club head may include at least a turbulator, sole transition profile, crown transition profile, rear transition profile, and dorsal cavity. Generally, the aerodynamic drag of a golf club head is dominated by the shape of the body that causes flow separation (i.e., pressure drag / shape drag). Compared with modern "flattened" clubs, the club head of the present invention may generate less drag during the swing due to a smaller surface area or volume, and the smaller surface area or volume may be introduced to achieve the target Iyy value. Compared with more bulbous prior art club heads, the club head of the present invention can generate less drag during the swing due to integrated aerodynamic features.

[0168] In some embodiments, the club head can include a plurality of turbulators as described in U.S. Patent Application No. 13 / 536,753, filed June 28, 2021, now U.S. Patent No. 8,608,587, issued December 17, 2013, entitled "Golf Club Heads with Turbulators and Methods to Manufacture Golf Club Heads with Turbulators," which is hereby incorporated by reference in its entirety. Turbulators on the crown are known in the art to reduce drag. Turbulators disrupt the airflow, thereby activating the flow and delaying flow separation. Thus, turbulators reduce the drag force generated by the club head during a swing and increase ball speed.

[0169] The club head can further include a crown transition profile, a sole transition profile, and / or a rear transition profile similar to the crown transition profile, the sole transition profile, and / or the rear transition profile described in U.S. Patent Application No. 15 / 233,486, filed on August 10, 2016, now U.S. Patent No. 10,035,048, issued on July 31, 2018, which is incorporated herein by reference in its entirety. The club head can include a front curvature radius, a sole curvature radius, and / or a rear curvature radius similar to the first crown curvature radius, the first sole curvature radius, and / or the rear curvature radius described in U.S. Patent Application No. 15 / 233,486, filed on August 10, 2016, now U.S. Patent No. 10,035,048, issued on July 31, 2018, titled "Golf Club Head with Transition Profiles to Reduce Aerodynamic Drag".

[0170] The front curvature radius can be from 0.18 to 0.30 inches (0.46 to 0.76 cm). Further, in other embodiments, the front curvature radius 392 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).

[0171] The curvature radius of the sole can range from about 0.25 to 0.50 inches (0.76 to 1.27 cm). In some embodiments, the curvature radius of the sole can be less than 0.5 inches (1.27 cm), less than 0.475 inches (1.21 cm), less than 0.45 inches (1.14 cm), or less than 0.40 inches (1.02 cm).

[0172] The radius of curvature of the rear portion can range from 0.10 to 0.25 inches (0.25 to 0.64 cm). In some embodiments, the radius of curvature of the rear portion can be less than 0.3 inches (0.76 cm), less than 0.275 inches (0.70 cm), less than 0.25 inches (0.64 cm), less than 0.225 inches (0.57 cm), or less than 0.20 inches (0.51 cm).

[0173] In addition, the club head can further include cavities located at the rear end and trailing edge of the club head similar to the cavities described in U.S. Patent Application No. 14 / 882,092, titled "Golf Club Heads with Aerodynamic Features and Related Methods," which is hereby incorporated by reference in its entirety and is now U.S. Patent No. 9,492,721, issued on November 15, 2016. In many embodiments, the cavity 420 can split the vortex generated behind the golf club head 300 into smaller vortices, reducing the size of the wake and / or reducing drag.

[0174] ( Example ) VII. Example 1: 3700 g*cm 2 Iyy target The first exemplary club head was designed to maximize performance within the framework of the Iyy target. The first exemplary club head had a body shaped like a cube and most of the mass of the club head arranged near the Y' axis. The first exemplary club head was designed with an Iyy target value of 3700 g*cm 2 and had a body width W of 4.4 inches B , a body height H of 2.31 inches B , a body depth D of 4.31 inches B , and a volume of 446 cm 3 . With these body dimensions, H B / WB The ratio was 0.53, H B / D B The ratio was 0.54. The club head further included a mass pad that covered most of the inner surface of the sole. The mass pad had a mass of 24 grams and was disposed at the central portion of the sole so as to intersect the Y' axis. Further, 11.2% of the total mass of the exemplary club head was located within a central mass zone having a radius R of 0.75 inches. The exemplary club head further included a removable weight member that was coupled to the body between the rear end and the sole at a very low and rearward position and had a mass of 32 grams. The club head further included a multi-material body structure having a non-metallic member that formed most of the crown, a heel, a toe, and a part of the sole. CMZ

[0175] Due to the body shaping, mass distribution, weight member placement, and multi-material structure of the first exemplary club head, Ixx was 3051 g*cm 2 and Iyy was 3650 g*cm 2 As a result, the first exemplary club head had an Ixx / Iyy ratio of 0.84.

[0176] VIII. Example 2: 2600 g*cm with crown and sole mass pads 2 Iyy target The second exemplary club head was designed to maximize performance within the framework of an Iyy target. The second exemplary club head had a body shaped like a cube and included most of the club head mass disposed near the Y' axis. The second exemplary club head was designed with an Iyy target value of 2600 g*cm 2 . The second exemplary club head had a body width W of 3.95 inches B , a body height H of 2.44 inches B , a body depth D of 3.85 inches B , and a volume of 332 cm 3 . With these body dimensions, the H B / W B ratio was 0.62, the H B / D B ​The ratio became 0.63. The second exemplary club head further included a first mass pad disposed on the inner surface of the sole. The first mass pad was located at the central portion of the sole and intersected the Y' axis and the YZ plane. The first mass pad was spaced more than 10% of the body depth rearward from the leading edge. The first mass pad was entirely contained within a central mass zone with a radius R CMZ of 0.75 inches. The club head further included a second mass pad located on the inner surface of the crown. The second mass pad was located at the central portion of the crown and intersected the Y' axis and the YZ plane. The second mass pad was spaced more than 10% of the body depth rearward from the leading edge. The second mass pad was also entirely contained within the same central mass zone. The first mass pad and the second mass pad together had a mass of 22.3 grams. The club head further included a third mass pad located on the inner surface of the sole, behind the first mass pad. The third mass pad covered most of the inner surface of the sole between the first mass pad and the rear end of the club and had a mass of 46 grams. Further, 21% of the total mass of the exemplary club head was located within the central mass zone. The second exemplary club head had a single-material body structure without any additional weight members and without any non-metallic components.

[0177] The shaping of the body, the placement of the mass pads, and the mass distribution of the second exemplary club head resulted in an Ixx of 2077 g*cm 2 and an Iyy of 2568 g*cm 2 . Accordingly, the second exemplary club head had an Ixx / Iyy ratio of 0.81. Different from the exemplary club head 1, the exemplary club head 2 was able to achieve the Ixx / Iyy ratio without using additional weight members attached to the body. The exemplary club head 2 provided a high Ixx / Iyy ratio due to the centrally placed mass pads and the higher H B / W B and H B / D B ratio.

[0178] IX. Example 3: 2600 g*cm with rear weight2 Iyy target The third exemplary club head was designed to maximize performance within the framework of the Iyy target. The third exemplary club head had a body shaped like a cube and most of the mass of the club head arranged near the Y' axis. The third exemplary club head was designed with an Iyy target value of 2600 g·cm 2 . The third exemplary club head had a body width W of 3.6 inches B , a body height H of 2.4 inches B , a body depth D of 3.5 inches B , and a volume of 280 cm 3 . With these body dimensions, the H B / W B ratio was 0.67 and the H B / D B ratio was 0.69. The third exemplary club head further included a first mass pad disposed on the inner surface of the sole near the trailing edge. The first mass pad covered most of the rear half of the inner surface of the sole and was spaced more than 40% of the body depth from the leading edge. The first mass pad was provided at a very sole-side position. The first mass pad had a mass of 33 grams. The club head further included a second mass pad located on the inner surface of the crown. The second mass pad was located at the central portion of the crown and intersected the Y' axis and the YZ plane. The second mass pad was spaced more than 10% of the body depth rearward from the leading edge. The second mass pad was entirely contained within a central mass zone with a radius R CMZ of 0.75 inches. Further, 20.8% of the total mass of the exemplary club head was located within the central mass zone. The third exemplary club head further included a weight member coupled to the outside rear of the club head at a very low rear position and having a mass of 30 grams. The third exemplary club head had a single-material body structure without any non-metallic components.

[0179] As a result of the body shaping, mass pad placement, mass distribution, and weight member of the third exemplary club head, Ixx was 2258 g·cm 2 , Iyy was 2475 g·cm2 resulted. Thus, the third exemplary club head had an Ixx / Iyy ratio of 0.88. The third exemplary club head achieved a very high Ixx / Iyy ratio by providing a combination of a very high H B / W B ratio and H B / D B ratio, a heavy mass pad at a very low position on the sole inner surface, a second mass pad located at the center on the crown, and a weight rear weight at a very low and rear position.

[0180] X. Example 4: 2700 g*cm with rear weight, crown, and sole mass pads 2 Iyy target The fourth exemplary club head was designed to maximize performance within the Iyy target frame. The fourth exemplary club head had a body shaped like a cube and most of the club head mass arranged near the Y' axis. The fourth exemplary club head was designed for an Iyy target of 2700 g*cm 2 . The fourth exemplary club head had a body width W of 3.96 inches B , a body height H of 2.23 inches B , a body depth D of 3.74 inches B , and a volume of 291 cm 3 . With these body dimensions, the H B / W B ratio was 0.56 and the H B / D B ratio was 0.69. The fourth exemplary club head further included a first mass pad located on the inner surface of the sole, the first mass pad was 50 grams, the first mass pad was located at the central portion of the sole and intersected the Y' axis and the YZ plane. The first mass pad was spaced rearward from the leading edge by a distance greater than 10% of the body depth. The first mass pad had a first radius R of 0.825 inches CMZ1It was entirely located within the first central mass zone having [it]. The club head further included a second mass pad located on the inner surface of the crown, and the second mass pad was about 6 grams. The second mass pad was located at the central portion of the crown and intersected the Y' axis and the YZ plane. The second mass pad was spaced more than 10% of the body depth rearward from the leading edge. The second mass pad had a second radius R of 0.50 inches CMZ2 and was entirely located within the second central mass zone having [it]. Further, 25% of the exemplary club head total mass was located within the third central mass zone having a third radius R of 0.75 inches CMZ3 The fourth exemplary club head was coupled externally to the rear of the club head at a very low rearward position and further included a weight member having a mass of 16 grams. The fourth exemplary club head had a single material body structure without any non-metallic components.

[0181] Due to the shaping of the body of the fourth exemplary club head, the placement of the mass pads, the mass distribution, and the weight member, Ixx was 2161 g*cm 2 and Iyy was 2679 g*cm 2 resulting in the fourth exemplary club head having an Ixx / Iyy ratio of 0.80. The fourth exemplary club head had a high Ixx / Iyy ratio due to the large proportion of the mass located within the central mass zone provided by the first and second centrally located mass pads. However, compared to the exemplary club heads 1 to 3, the exemplary club head 4 showed a slightly lower Ixx / Iyy ratio, presumably due to its relatively low H B / W B ratio.

[0182] XI. Example 5: Comparison of Ixx / Iyy ratio The dimensions of the club head bodies of the first, second, third, and fourth exemplary clubs described above (body height H B , body width W B and body depth D B) And the moment of inertia was compared with a plurality of control club heads representative of that prior art. The control club heads were designed to maximize Iyy rather than maximizing the Ixx / Iyy ratio. Control club head 1 represents a "modern" prior art club head with an overall flat club head shape. Control club head 1 was designed to maximize Iyy by means of high peripheral weighting and a multi-material body structure with non-metallic components forming most of the crown. Control club head 2, control club head 3, and control club head 4 represent old prior art club heads that tend to have a more bulbous club head shaping but have no specific weight structure, weight member, or mass distribution designed to increase the Ixx / Iyy ratio. The dimensions of each club head are shown in Table 1 below.

Table 1

[0183] As is apparent from Table 1 above, the exemplary club head showed an increased Ixx / Iyy ratio compared to both the flatter and more modern control club head 1 and the more bulbous and more traditional control club heads 2 - 4. With respect to control club head 1, the increase in the Ixx / Iyy ratio shown by the exemplary club head is due to the shaping of the club head. The exemplary club head had a significantly more cube-like body shape than control club head 1. The exemplary club head had a 10% to 40% increase in the H B / W B ratio and a 10% to 41% increase in the H B / D B ratio. As a result of the increase in the H B / W B ratio and the H B / D B ratio, the Ixx / Iyy ratio increased by 4% to 14% compared to control club head 1.

[0184] For the control club head 2-4, the exemplary club head showed an Ixx / Iyy ratio that increased from 33% to 49%. The control club head 2-4 had an H B / W B and an H B / D B ratio, but the control club head did not have the weighting features or mass distribution near the Y'-axis as described above in relation to the exemplary club head. Despite the bulbous shape of the control club head 2-4, due to the absence of a mass pad, weight member, or mass placement near the Y'-axis, a substantially low Ixx value was obtained. This example illustrates that a high Ixx / Iyy ratio is achieved by a combination of a body shape like a cube and a discretionary mass placement near the Y'-axis.

[0185] XII. Example 6: Deviation of offline distance from optimal bulge radius (Iyy target: 2000 g*cm 2 This example, as described in the above embodiments, illustrates the significance of providing an optimal bulge radius for a given club head. Referring to FIG. 25, the exemplary golf club head was configured such that the target Iyy was 2000 g*cm 2 , and further Ixx was 1480 g*cm 2 , and the COR was 0.785. Based on the relationships 1-4 detailed above, the club head had a striking face with optimal bulge and roll curvatures. The optimal bulge radius was 6.77 inches and the optimal roll radius was 4.59 inches. FIG. 25 shows, for the exemplary club head, the percentage increase in the standard deviation of the offline distance that would result from deviation from the optimal bulge radius ("percent change in bulge radius"). This graph shows the detrimental effect of giving a sub-optimal bulge radius to the exemplary club head. As shown in FIG. 25, as the bulge radius deviates from the optimal value, the club head shows a substantial decrease in accuracy (i.e., an increase in the offline distance from the target line).

[0186] As shown at points 2010 and 2020, even a slight deviation from the optimal bulge curvature leads to a significant loss of accuracy. Point 2010 shows a bulge radius that is 2 inches smaller (29.5% smaller) than the optimal bulge radius, resulting in a 54.3% increase in the offline distance standard deviation. Point 2020 shows a bulge radius that is 2 inches larger (29.5% larger) than the optimal bulge radius, resulting in a 15.1% increase in the offline distance standard deviation. This example shows that even a small amount (i.e., just 2 inches) of deviation from the optimal bulge radius is detrimental to accuracy. Therefore, providing a bulge curvature optimized for a particular club head according to the present invention is extremely important in maximizing the tolerance of the club head. This is particularly true for club heads with a low Iyy target, as the optimized bulge curvature and roll curvature compensate for the tolerance lost by providing a low Iyy.

[0187] XIII. Example 7: Deviation of offline distance from optimal bulge radius (Iyy target: 3200 g*cm 2 This example further illustrates the significance of providing an optimal bulge radius for a given club head, as described in the above embodiments. Referring to FIG. 26, an exemplary golf club head is configured with a target Iyy of 3200 g*cm 2 and further has an Ixx of 2368 g*cm 2 and a COR of 0.814. Based on the relationships 1-4 detailed above, the club head has a striking face with an optimal bulge curvature and roll curvature. The optimal bulge radius was 9.34 inches and the optimal roll radius was 6.31 inches. FIG. 26 shows, for the exemplary club head, the percentage increase in the offline distance standard deviation that would result from a deviation from the optimal bulge radius (the "percent change in bulge radius"). This graph shows the detrimental effects of giving a near-optimal bulge radius to the exemplary club head. As shown in FIG. 26, as the bulge radius deviates from the optimal value, the club head shows a significant decrease in accuracy (i.e., an increase in the offline distance from the target line).

[0188] As indicated by points 3010 and 3020, even a slight deviation from the optimal bulge curvature leads to a significant loss of accuracy. Point 3010 shows a bulge radius that is 2 inches smaller (21.4% smaller) than the optimal bulge radius, resulting in a 12.97% increase in the offline distance standard deviation. Point 3020 shows a bulge radius that is 2 inches larger (21.4% larger) than the optimal bulge radius, resulting in a 4.32% increase in the offline distance standard deviation. This example shows that deviating by a small amount (i.e., just 2 inches) from the optimal bulge radius can have an adverse effect on accuracy. Therefore, providing a bulge curvature optimized according to the present invention for a particular club head is important in maximizing the tolerance of the club head.

[0189] XIV. Example 8: Standard bulge radius and roll radius vs. optimized bulge radius and roll radius A plurality of exemplary club heads having a face optimized with a bulge curvature and a roll curvature according to the present invention were compared with a plurality of corresponding control club heads having a standard bulge curvature and a roll curvature not optimized for the particular characteristics of the club head. Each exemplary club head corresponded to a control club head having the same characteristics except for the difference in bulge curvature and roll curvature. Each control club head had a 12-inch bulge radius and a 12-inch roll radius, which are typical curvatures of the prior art for driver-type club heads. The optimized bulge radius and roll radius of the exemplary club heads were according to the ranges specified in the above description and were significantly lower than the standard bulge radius and roll radius of the control club heads. Table 2 below compares the average carry distance and the standard deviation of the offline distance for combinations of a plurality of exemplary club heads and control club heads, and each combination had different combinations of Iyy target and COR.

Table 2

[0190] The exemplary clubhead provides a significant increase in both carry distance and offline distance as compared to a corresponding conventional clubhead. The exemplary clubhead showed a significant increase in carry distance between 3.25 yards (a 1.2% increase) and 11.56 yards (a 4.3% increase) as compared to the corresponding conventional clubhead. Further, the exemplary clubhead showed a significant decrease in the standard deviation of the offline distance between 2.76 yards (a 17% decrease) and 10.86 yards (a 45% decrease). This result shows that applying industry standard bulge and roll radii (12 inches) cannot maximize both carry distance and offline accuracy. In contrast, the exemplary clubhead with optimized bulge curvature and roll curvature significantly improves carry distance and accuracy.

[0191] Optimizing the bulge curvature and roll curvature in accordance with the present invention, and the relationships discussed in the above description, provide a golf clubhead that hits the ball farther and is dramatically more forgiving. Further, all of the exemplary clubheads showed improvement over the conventional clubhead regardless of the Iyy target, although the improvement tended to be more pronounced for clubheads with lower MOI. This result shows that the bulge radius and roll radius of the present invention provide performance improvement for any MOI. Nevertheless, the optimized bulge curvature and roll curvature of the present invention are uniquely beneficial for low MOI clubheads. Optimization of the bulge curvature and roll curvature can compensate for the natural loss of forgiveness associated with low MOI clubheads.

[0192] XV. Example 9: High MOI club head vs. low MOI club head with bulge radius and roll radius determined from the center of gravity position An exemplary clubhead having a hitting face with a low MOI target and optimized bulge curvature and roll curvature was compared to a prior art high MOI clubhead (hereinafter "conventional clubhead") having standard bulge curvature and roll curvature that are not optimized for specific characteristics of the clubhead. The exemplary clubhead had an Iyy of 2600 g*cm 2 , an Ixx of 1924 g*cm 2, with a COR of 0.785. The control clubhead has Iyy of 5700 g*cm 2 , Ixx of 4218 g*cm 2 , with a COR of 0.83. The control clubhead further has a bulge radius and a roll radius of approximately 12 inches each. Table 3 below compares the average carry distance and the offline distance standard deviation of the control clubhead and the exemplary clubhead.

Table 3

[0193] As shown in Table 3, the exemplary clubhead showed a decrease in carry distance. However, the decrease in carry distance can be attributed to the difference in COR rather than the bulge curvature and the roll curvature. Despite the exceptionally low moment of inertia, the exemplary clubhead showed an improvement in accuracy compared to the high MOI golf clubhead. Despite having a 54% decrease in Iyy, the exemplary clubhead showed a 10.9% decrease in the offline distance standard deviation. This result shows that the optimized bulge curvature and roll curvature can overcome the defects introduced by reducing the moment of inertia of the clubhead and even bring about an improvement in accuracy compared to the high MOI clubhead.

[0194] XVI. Example 10: Club head with adjustable swing weight and constant Iyy The exemplary clubhead has 0.1 g*cm in clubhead Iyy 2Designed with an adjustable swing weight system that enables achieving a variation in the total club head mass of 26g with less variation. An exemplary club head with an adjustable swing weight system was substantially similar to the embodiments shown in FIGS. 18 to 20. The adjustable swing weight system of the exemplary club head comprised a plurality of replaceable and / or removable weight inserts including a lightweight weight insert, a medium weight insert, and a heavy weight insert. Each of the plurality of weight inserts corresponded to the construction of the exemplary club head including the construction of the lightweight club head (associated with the lightweight weight insert), the construction of the medium weight club head (associated with the medium weight insert), and the construction of the heavy weight club head (associated with the heavy weight insert). Each of the plurality of weight inserts was associated with a unique discrete position within the tubular recess and a weight insert offset (O W ) value.

[0195] The length of the tubular recess of the exemplary club head was 2.25 inches. The lightweight weight insert was disposed nearer to the rear of the tubular recess, providing an offset value O of 2.20 inches along the line of force from the center of gravity of the club head. Wを The medium weight insert was disposed nearer to the center of the tubular recess, with an offset value O of 1.63 inches. W The heavy weight insert was positioned nearer to the front of the tubular recess and the heavy weight insert, with an offset value O of 1.38 inches. Wwas provided. The lightweight weight insert of the exemplary club head had a mass of 14.87 grams, the medium weight insert had a mass of 27.87 grams, and the heavy weight insert had a mass of 40.87 grams. The mass of the club head without the weight insert was held at a constant value of 175.20 grams. Since the interchangeable and / or removable weight inserts were configured within the same club head body, any variation in club head Iyy could only be attributed to changing the weight insert and its position. The different masses of the weight inserts were varied by providing different shapes and densities to each weight insert. The density of the lightweight weight insert was 9.44 g / cm 3 and the density of the medium weight insert was 12.59 g / cm 3 and the density of the heavy weight insert was 17.31 g / cm 3 . The club head mass, weight insert mass, selected values of weight insert offsets, and the Iyy values obtained for each build are summarized in Table 4 below. This example shows the ability of an adjustable swing weight system to provide a constant Iyy between builds to match a desired Iyy target. Therefore, the Ixx values are not reported in Table 4.

Table 4

[0196] As shown in Table 4, the exemplary adjustable swing weight system allows the total club head mass to vary by 26 grams while maintaining a constant club head Iyy.

[0197] The configurations shown in Table 4 for the lightweight club head build, medium club head build, and heavy club head build were 2667 g*cm 2Based on the Iyy target of, a minimum desired club head build mass of 190 grams, and a desired maximum club head build mass of 216 grams. The selected Iyy target, number of weight inserts, and desired swing weight are for illustrative purposes and do not indicate the limits of the adjustable swing weight system described herein. For example, if it is determined that it is desirable to achieve a larger numerical Iyy target with the total club head mass, the club head can be designed to have a greater length of the tubular recess, thereby placing the weight further from the center of gravity of the club head and achieving a larger Iyy value. Similarly, if it is considered desirable to achieve a greater variation in swing weight across different club head builds, a plurality of weight inserts with greater mass variation can be selected and the weight inserts can be arranged accordingly.

[0198] (Article) Clause 1. A golf club head comprising a striking face having a geometric center and a leading edge, a body, a center of gravity, a ground contact surface, and a total club head mass, the body comprising a crown, a sole, a heel, a toe, and a rear end, the golf club head comprising a primary coordinate system centered on the geometric center and a secondary coordinate system centered on the center of gravity, the primary coordinate system defining an X-axis extending from the heel to the toe direction and parallel to the ground contact surface, a Y-axis extending from the crown to the sole direction and orthogonal to the X-axis and the ground contact surface, and a Z-axis extending rearward from the striking face and orthogonal to both the X-axis and the Y-axis, the secondary coordinate system defining an X'-axis extending from the heel to the toe direction and parallel to the ground contact surface, a Y'-axis extending from the crown to the sole direction and orthogonal to the X'-axis and the ground contact surface, and a Z'-axis extending rearward from the striking face and orthogonal to both the X'-axis and the Y'-axis, the body comprising a body width measured parallel to the X-axis between the heel and the toe, a body depth measured parallel to the Z-axis between the leading edge and the rearmost point of the body, and a body height measured parallel to the Y-axis between the ground contact surface and the highest point of the crown, the club head comprising a ratio HB / WB obtained by dividing the body height by the body width, the ratio HB / WB being greater than 0.6, the ratio HB / WB, the moment of inertia Ixx about the X'-axis, the moment of inertia Iyy about the Y'-axis, the moment of inertia Izz about the Z'-axis, and a central mass zone defined by a virtual cylinder centered on the Y'-axis, the central mass zone defining a central mass zone radius of 0.75 inches, the club head having an Ixx / Iyy ratio greater than 0.8 and more than 20% of the total club head mass being located within the central mass zone.

[0199] Clause 2. The golf club head according to Clause 1, further comprising a crown mass pad located on the inner surface of the crown and a sole mass pad located on the inner surface of the sole, the crown mass pad and the sole mass pad each intersecting the Y'-axis.

[0200] Clause 3. The golf club head according to Clause 2, wherein at least one of the crown mass pad and the sole mass pad is entirely surrounded within the central mass zone.

[0201] Clause 4. The golf club head according to clause 2, wherein the sole mass pad has a mass greater than 5 grams.

[0202] Clause 5. The golf club head according to clause 2, wherein the crown mass pad has a mass greater than 25 grams.

[0203] Clause 6. The golf club head according to clause 1, wherein the body width is less than 4.0 inches.

[0204] Clause 7. The golf club head according to clause 1, wherein the body height is greater than 2.2 inches.

[0205] Clause 8. The golf club head according to clause 1, wherein the club head has a volume of less than 350 cm 3 .

[0206] Clause 9. The golf club head according to clause 1, wherein the Ixx / Iyy ratio is greater than 0.85.

[0207] Clause 10. The golf club head according to clause 1, further comprising a YZ plane extending along the Y axis and the Z axis, a crown transition point located at the foremost point of the crown in the YZ plane, a rear transition point located at the rearmost point of the crown in the YZ plane, a crown axis extending between the crown transition point and the rear transition point, and a crown angle measured as an acute angle between the crown axis and the Y' axis, wherein the crown angle is greater than 75 degrees.

[0208] Clause 11. The golf club head according to clause 10, wherein the crown angle is greater than 85 degrees.

[0209] Clause 12. The golf club head further comprises a weight member attached to the body near the rear end and the sole, the weight member defines a center of gravity of the weight member, the weight member is defined as the distance between the center of gravity of the club head and the center of gravity of the weight member, the weight member has a weight member height measured parallel to the Y' axis, the weight member is defined as the distance between the center of gravity of the club head and the center of gravity of the weight member, the weight member further has a weight member depth measured parallel to the Y' axis, the club head defines an EW / DW ratio defined as the weight member height divided by the weight member depth, and the EW / DW ratio is greater than 0.3, the golf club head according to Clause 1.

[0210] Clause 13. A golf club head comprising a striking face having a geometric center and a leading edge, a body, a center of gravity, a ground contact surface, and a total club head mass, the body comprising a crown, a sole, a heel, a toe, and a rear end, the golf club head comprising a primary coordinate system centered on the geometric center and a secondary coordinate system centered on the center of gravity, the primary coordinate system extending from the heel to the toe direction and parallel to the ground contact surface with an X axis, extending from the crown to the sole direction and perpendicular to both the X axis and the ground contact surface with a Y axis, and extending rearward from the striking face and perpendicular to both the X axis and the Y axis with a Z axis, the secondary coordinate system extending from the heel to the toe direction and parallel to the ground contact surface with an X' axis, extending from the crown to the sole direction and perpendicular to both the X' axis and the ground contact surface with a Y' axis, and extending rearward from the striking face and perpendicular to both the X' axis and the Y' axis with a Z' axis, the body having a body width measured parallel to the X axis between the heel and the toe, a body depth measured parallel to the Z axis between the leading edge and the rearmost point of the body, and a body height measured parallel to the Y axis between the ground contact surface and the highest point of the crown, the club head having a ratio H B / W B where the ratio H B / W B is greater than 0.6, the ratio H B / W Band a moment of inertia Ixx about the X' axis, a moment of inertia Iyy about the Y' axis, a moment of inertia Izz about the Z' axis, and a central mass zone defined by a virtual cylinder centered on the Y' axis, the central mass zone defining a central mass zone radius of 0.75 inches, and a club head having an Ixx / Iyy ratio greater than 0.8, the club head defining a mass distribution metric MD1 according to Equation 1,

Number

[0211] Clause 14. The golf club head according to Clause 13, further comprising a crown mass pad located on the inner surface of the crown and a sole mass pad located on the inner surface of the sole, the crown mass pad and the sole mass pad each intersecting the Y' axis.

[0212] Clause 15. The golf club head according to Clause 14, wherein at least one of the crown mass pad and the sole mass pad is entirely surrounded within the central mass zone.

[0213] Clause 16. A golf club head comprising a striking face having a geometric center and a leading edge, a body, a center of gravity, a ground contact surface, and a total club head mass, the body comprising a crown, a sole, a heel, a toe, and a trailing edge, the golf club head comprising a primary coordinate system centered on the geometric center and a secondary coordinate system centered on the center of gravity, the primary coordinate system defining an X-axis extending from the heel to the toe direction and parallel to the ground contact surface, a Y-axis extending from the crown to the sole direction and orthogonal to the X-axis and the ground contact surface, and a Z-axis extending rearward from the striking face and orthogonal to both the X-axis and the Y-axis, the secondary coordinate system defining an X'-axis extending from the heel to the toe direction and parallel to the ground contact surface, a Y'-axis extending from the crown to the sole direction and orthogonal to the X'-axis and the ground contact surface, and a Z'-axis extending rearward from the striking face and orthogonal to both the X'-axis and the Y'-axis, the body comprising a body width measured parallel to the X-axis between the heel and the toe, a body depth measured parallel to the Z-axis between the leading edge and the rearmost point of the body, and a body height measured parallel to the Y-axis between the ground contact surface and the highest point of the crown, the club head having a ratio H B / W B where the ratio H B / W B is greater than 0.6, the ratio H B / W B and a moment of inertia Ixx about the X'-axis, a moment of inertia Iyy about the Y'-axis, a moment of inertia Izz about the Z'-axis, and a central mass zone defined by a virtual cylinder centered on the Y'-axis, the central mass zone defining a central mass zone radius of 0.75 inches, the club head having an Ixx / Iyy ratio greater than 0.8, the club head defining a mass distribution metric MD3 according to Equation 1, [Number] M CMZ is the amount of mass within the central mass zone, M T is the total club head mass, and the mass distribution metric MD3 is greater than 0.050, the golf club head.

[0214] Clause 17. The golf club head according to clause 16, further comprising a crown mass pad located on the inner surface of the crown and a sole mass pad located on the inner surface of the sole, wherein the crown mass pad and the sole mass pad each intersect the Y' axis.

[0215] Clause 18. The golf club head according to clause 17, wherein at least one of the crown mass pad and the sole mass pad is entirely surrounded within the central mass zone.

[0216] Clause 19. The golf club head according to clause 16, wherein Iyy is less than 3200 g*cm 2 Clause 20. The golf club head according to clause 16, wherein Iyy is less than 2800 g*cm

[0217] Clause 20. The golf club head according to clause 16, wherein Iyy is less than 2800 g*cm 2 Clause 21. The striking face further comprises a bulge curvature and a roll curvature, the bulge curvature having a bulge radius that satisfies Relational Expression 1.

[0218] Clause 21. The striking face further comprises a bulge curvature and a roll curvature, the bulge curvature having a bulge radius that satisfies Relational Expression 1.

Number

[0219] Clause 22. The golf club head according to clause 16, wherein the club head comprises a plurality of replaceable weight inserts, each of the plurality of replaceable weight inserts is associated with a different club head construction, each club head construction is associated with a different club head total mass, and Iyy is constant among the different club head constructions.

Claims

1. A golf club head, comprising a striking face having a geometric center and a leading edge, a body, a center of gravity, a ground contact surface, and a total club head mass, the body comprising a crown, a sole, a heel, a toe, and a rear end, the golf club head comprising a primary coordinate system centered on the geometric center and a secondary coordinate system centered on the center of gravity, the primary coordinate system comprising an X-axis extending from the heel to the toe direction and parallel to the ground contact surface, a Y-axis extending from the crown to the sole direction and orthogonal to the X-axis and the ground contact surface, and a Z-axis extending rearward from the striking face and orthogonal to both the X-axis and the Y-axis, defining, the secondary coordinate system comprising an X'-axis extending from the heel to the toe direction and parallel to the ground contact surface, a Y'-axis extending from the crown to the sole direction and orthogonal to the X'-axis and the ground contact surface, and a Z'-axis extending rearward from the striking face and orthogonal to both the X'-axis and the Y'-axis, defining, the body comprising a body width measured parallel to the X-axis between the heel and the toe, a body depth measured parallel to the Z-axis between the leading edge and the rearmost point of the body, and a body height measured parallel to the Y-axis between the ground contact surface and the highest point of the crown, the club head comprising The ratio H obtained by dividing the body height by the body width Ｂ / W Ｂ is such that the ratio H Ｂ / W Ｂ is greater than 0.6, and the ratio H Ｂ / W Ｂ and a moment of inertia Ixx about the X'-axis, a moment of inertia Iyy about the Y'-axis, a moment of inertia Izz about the Z'-axis, a central mass zone defined by a virtual cylinder centered on the Y'-axis, the central mass zone defining a central mass zone radius of 0.75 inches, the central mass zone, the club head having an Ixx / Iyy ratio greater than 0.8, and more than 20% of the total club head mass is located within the central mass zone. A golf club head.

2. further comprising a crown mass pad located on the inner surface of the crown and a sole mass pad located on the inner surface of the sole, the crown mass pad and the sole mass pad each intersecting the Y'-axis. The golf club head according to claim 1.

3. At least one of the crown mass pad and the sole mass pad is entirely surrounded within the central mass zone. The golf club head according to claim 2.

4. The golf club head according to claim 2, wherein the sole mass pad has a mass of more than 5 grams. **Claim 5** The golf club head according to claim 2, wherein the crown mass pad has a mass greater than 25 grams. **Claim 6** The golf club head according to claim 1, wherein the body width is less than 4.0 inches. **Claim 7** The golf club head according to claim 1, wherein the body height is greater than 2.2 inches. **Claim 8** The club head has a volume of less than 350 cm ３ The golf club head according to claim 1, having a volume of less than 350 cm **Claim 9** The golf club head according to claim 1, wherein the Ixx / Iyy ratio is greater than 0.

85. **Claim 10** a YZ plane extending along the Y axis and the Z axis, a crown transition point located at the foremost point of the crown in the YZ plane, a rear transition point located at the rearmost point of the crown in the YZ plane, a crown axis extending between the crown transition point and the rear transition point, a crown angle measured as an acute angle between the crown axis and the Y' axis, further comprising, the crown angle being greater than 75 degrees, the golf club head according to claim 1. **Claim 11** The golf club head according to claim 10, wherein the crown angle is greater than 85 degrees. **Claim 12** further comprising a weight member attached to the body near the rear end and the sole, the weight member defining a weight member center of gravity, the weight member having a weight member height defined as the distance between the center of gravity of the club head and the center of gravity of the weight member, measured parallel to the Y' axis, the weight member further having a weight member depth defined as the distance between the center of gravity of the club head and the center of gravity of the weight member, measured parallel to the Y' axis, The club head defines a ratio E Ｗ / D Ｗ defined as the height of the weight member divided by the depth of the weight member, The aforementioned E Ｗ / D Ｗ ratio is greater than 0.3, the golf club head according to claim 1. **Claim 13** A golf club head, comprising a striking face having a geometric center and a leading edge, a body, a center of gravity, a ground contact surface, and a total club head mass, the body comprising a crown, a sole, a heel, a toe, and a rear end, the golf club head comprising a primary coordinate system centered on the geometric center and a secondary coordinate system centered on the center of gravity, the primary coordinate system is an X axis extending from the heel to the toe direction and parallel to the ground contact surface, a Y axis extending from the crown to the sole direction and orthogonal to the X axis and the ground contact surface, a Z axis extending rearward from the striking face and orthogonal to both the X axis and the Y axis, defining, the secondary coordinate system is an X' axis extending from the heel to the toe direction and parallel to the ground contact surface, Extending from the crown towards the sole, the X'-axis and the Y'-axis orthogonal to the ground contact surface, Extending rearward from the striking face, the Z'-axis orthogonal to both the X'-axis and the Y'-axis, are defined, The body is, The body width measured parallel to the X-axis between the heel and the toe, The body depth measured parallel to the Z-axis between the leading edge and the rearmost point of the body, The body height measured parallel to the Y-axis between the ground contact surface and the highest point of the crown, are provided, The club head is, The ratio H obtained by dividing the body height by the body width Ｂ / W Ｂ wherein the ratio H Ｂ / W Ｂ is greater than 0.6, the ratio H Ｂ / W Ｂ and The moment of inertia Ixx about the X'-axis, The moment of inertia Iyy about the Y'-axis, The moment of inertia Izz about the Z'-axis, The central mass zone defined by a virtual cylinder centered on the Y'-axis, the central mass zone defining a central mass zone radius of 0.75 inches, the central mass zone, are provided, The club head has an Ixx / Iyy ratio greater than 0.8, The club head defines a mass distribution metric MD according to relational expression 1 １ and M ＣＭＺ is the amount of mass within the central mass zone, M Ｔ is the total clubhead mass, R ＣＭＺ is the central mass zone radius, The mass distribution metric MD １ is greater than 0.1, golf club head.

14. Further comprising a crown mass pad located on the inner surface of the crown and a sole mass pad located on the inner surface of the sole, The golf club head according to claim 13, wherein the crown mass pad and the sole mass pad each intersect the Y'-axis.

15. The golf club head according to claim 14, wherein at least one of the crown mass pad and the sole mass pad is entirely surrounded within the central mass zone.

16. A golf club head, Comprising a striking face having a geometric center and a leading edge, a body, a center of gravity, a ground contact surface, and a total club head mass, The body comprises a crown, a sole, a heel, a toe, and a rear end, The golf club head comprises a primary coordinate system centered on the geometric center and a secondary coordinate system centered on the center of gravity, The primary coordinate system is, Extending from the heel towards the toe, the X-axis parallel to the ground contact surface, Extending from the crown towards the sole, the Y-axis orthogonal to the X-axis and the ground contact surface, Extending rearward from the striking face, the Z-axis orthogonal to both the X-axis and the Y-axis, are defined, The secondary coordinate system is, Extending from the heel towards the toe, the X'-axis parallel to the ground contact surface, Extending from the crown towards the sole, the Y'-axis orthogonal to the X'-axis and the ground contact surface, Extending rearward from the striking face, the Z'-axis orthogonal to both the X'-axis and the Y'-axis, are defined, The body is, A body width measured parallel to the X-axis between the heel and the toe, a body depth measured parallel to the Z-axis between the leading edge and the rearmost point of the body, and a body height measured parallel to the Y-axis between the ground contact surface and the highest point of the crown, The club head The ratio H obtained by dividing the body height by the body width Ｂ / W Ｂ wherein the ratio H Ｂ / W Ｂ is greater than 0.6, and the ratio H Ｂ / W Ｂ and has a moment of inertia Ixx about the X'-axis, a moment of inertia Iyy about the Y'-axis, a moment of inertia Izz about the Z'-axis, and a central mass zone defined by a virtual cylinder centered on the Y'-axis, the central mass zone defining a central mass zone radius of 0.75 inches, The club head has an Ixx / Iyy ratio greater than 0.8, The club head defines a mass distribution metric MD according to relational expression 1 ３ and M ＣＭＺ is the amount of mass within the central mass zone, M Ｔ is the total clubhead mass, and the mass distribution metric MD ３ is greater than 0.050, a golf clubhead.

17. further comprises a crown mass pad located on the inner surface of the crown and a sole mass pad located on the inner surface of the sole, The golf club head according to claim 16, wherein the crown mass pad and the sole mass pad each intersect the Y'-axis.

18. The golf club head according to claim 17, wherein at least one of the crown mass pad and the sole mass pad is entirely surrounded within the central mass zone.

19. Iyy is less than 3200 g*cm ２ The golf club head according to claim 16, wherein Iyy is less than 3200 g*cm

20. Iyy is less than 2800 g·cm ２ The golf club head according to claim 16, wherein Iyy is less than 2800 g·cm

21. The striking face further has a bulge curvature and a roll curvature, the bulge curvature having a bulge radius that satisfies Equation 1, CG ｙ is the position of the center of gravity with respect to the Y axis, and CG Ｚ is the position of the center of gravity along the Z axis, the golf club head according to claim 16.

22. The club head comprises a plurality of replaceable weight inserts, each of the plurality of replaceable weight inserts being associated with a different club head construction, each club head construction being associated with a different club head total mass, The golf club head according to claim 16, wherein Iyy is constant among the different club head constructions.

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