MULTI-COMPONENT GOLF CLUB HEAD HAVING TUNING ELEMENTS - Patent application

Abstract

An embodiment of a multi-material wood-type golf club head is disclosed, which includes a tuning element. The multi-material wood-type golf club head includes a first metal component forming a strike face and portions of the crown, toe, and sole, and a second non-metal component forming a majority of the crown and portions of the heel, toe, and sole. The club head further includes a tuning element secured to an inner surface of the crown. The tuning element limits the amplitude of a hot spot in the club head to between 1 and 7 decibels.

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 127,869, filed on December 18, 2020, and U.S. Provisional Patent Application No. 63 / 082,925, filed on September 24, 2020. The entire contents of the above disclosures are hereby incorporated by reference in their entirety into this specification.

[0002] The present invention generally relates to golf equipment, and more particularly to a multi - component golf club head having tuning elements.

Background Art

[0003] The design of golf clubs takes into account several performance characteristics such as vibration and acoustic response. Vibration or acoustic response corresponds to the sound and feel of the golf club. At impact, the club head vibrates at various natural frequencies including various different amplitudes (also known as vibration "modes"). The design and structure of the club head determine the various different amplitudes that occur at various natural frequencies. The natural frequencies with high amplitudes are regarded as "dominant frequencies" and are the most significant contributor to the club head sound. If the amplitudes of the dominant frequencies are too high, the club head may sound annoying and unpleasant to the golfer. To provide a pleasant acoustic response at impact, the dominant vibrations must be suppressed (i.e., the amplitudes of such vibrations must be reduced). However, in many cases, damping means need to add a significant amount of mass to the club head at multiple locations, and at these locations, it has an adverse effect on mass characteristics such as the center of gravity (CG) position and the moment of inertia (MOI). Therefore, there is a need in the art for suitable lightweight means to suppress the dominant vibrations of a golf club head and provide a desired vibration response without adversely affecting the mass characteristics of the club head.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0015] This embodiment is directed to a wood-type club head (e.g., a driver club head, a fairway wood club head or a hybrid club head) in which a plurality of material structures include lightweight crown tuning elements. When the club head receives an impact of a golf ball, the tuning element suppresses or reduces the high amplitude occurring at the natural frequency, resulting in an improved acoustic response and a desired “softer” feel. The tuning element is accurately positioned at a location corresponding to the high amplitude occurring at the natural frequency. The tuning element improves the acoustic response of the club head without adding a significant amount of mass to the club head. The crown tuning element is a lightweight element or a low-mass element that improves the sound and feel of the club head during impact of the golf ball and maintains the overall club head design to maximize the moment of inertia of the club head and retain desired mass characteristics such as a low rear center of gravity position.

[0016] The tuning elements and the positions of the tuning elements described in the present disclosure are beneficial to the structure of the composite club head for accurate placement on the crown prior to assembly of the club head. Further, the tuning elements do not lose structural integrity due to the heat source used during the club head assembly process. For example, in the case of a club head having a metal component and a composite component, the tuning element is placed on the multi-component prior to assembly of the club head. Typically, in the case of a multi-component club head structure, the composite component is fixed to the metal component via an adhesive or mechanical means without using a heat source. The composite assembly process does not use a heat source, thereby maintaining the structural integrity of the tuning element. In contrast, all metal club heads are cast as a single body and the face plate is welded onto the body. Welding of the face plate requires a heat source and affects (e.g., melts) the structural integrity of any tuning element disposed within the internal cavity of the metal club head. The tuning elements described in the present disclosure are accurately placed on the crown without losing structural integrity or modifying material properties.

[0017] For example, the club head comprises a two-component design having a first component formed from a metallic material and a second component formed from a non-metallic material. The first component includes a load-bearing structure and a majority of the club head mass. The first component includes a rearwardly extending sole portion or sole rearward extension that extends away from the strike face. The first component having the sole extension may receive a removable weight for weight adjustment and may include structures such as ribs that structurally reinforce the club head. The second component comprises a lightweight composite structure. The lightweight composite structure wraps around the first component and forms a majority of the crown of the club head, as well as portions of the heel, toe, and sole.

[0018] The tuning element addresses the high amplitudes that occur at the dominant natural frequency. The high amplitudes that occur at the dominant natural frequency appear on the non-metallic or composite components of the clubhead. For example, the dominant natural frequency appears at the structurally weakest part of the composite component. The structurally weak part can include parts on the composite component that are thin or have a minimum thickness. The thin part of the composite component includes high amplitudes at the dominant natural frequency.

[0019] The tuning element is disposed on the crown portion of the second component so as to control sound. Specifically, the tuning element is disposed on the rear heel portion of the crown so as to suppress the amplitude that occurs at the dominant natural frequency. The tuning element addresses the high amplitudes that occur at dominant natural frequencies above 5000 Hz. A clubhead having a multi-material structure and a crown tuning element reduces the amplitude of the dominant vibration frequency by 1 to 7 decibels compared to a similar multi-component clubhead without the tuning element. A clubhead having a crown tuning element provides excellent sound control and minimizes the impact on the center of gravity and moment of inertia characteristics. Described below are some embodiments of a crown tuning element that improve the acoustic response of a multi-component clubhead during impact with a golf ball.

[0020] The terms "a", "an", "the", "at least one", and "one or more" are used interchangeably to indicate that there is at least one item, and multiple such items may be present unless the context clearly indicates otherwise. All values of parameters (e.g., amounts or conditions) in this specification, including the appended claims, should be understood to be modified in all cases by the term "about", whether or not the term "about" actually appears before the value. "About" indicates that the stated numerical value allows for some imprecision (some proximity to the exactness of the value, approximate or reasonably close to the value, or a rough approximation). If the imprecision given by "about" is not understood in the art in this ordinary sense, then as used herein, "about" indicates at least the variation that may result from the normal methods of measuring and using such parameters. Also, the disclosure of a range includes the disclosure of all values and of further divided ranges within the entire range. Each value within a range and the endpoints of the range are disclosed herein as all separate embodiments. The terms "comprising", "comprises", "including", and "having" are inclusive and thus specify the presence of the stated items but do not preclude the presence of other items. As used herein, the term "or" includes any and all combinations of one or more of the listed items. When terms such as first, second, third, etc. are used to identify various items from one another, these designations are merely for convenience and do not limit the items.

[0021] The terms "first", "second", "third", "fourth", and "fifth", etc. in the detailed description and claims are used, if any, to distinguish between similar elements and are not necessarily used to describe a particular sequential or chronological order. Such terms are interchangeable under appropriate circumstances, and it should be understood that the embodiments described herein are capable of operating in sequences other than, for example, those illustrated or otherwise described herein. Moreover, the terms "comprise" and "have", and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, article, device, or apparatus that includes a list of elements is not necessarily limited to those elements but may include other elements not expressly listed or inherent to such process, method, system, article, device, or apparatus.

[0022] Terms such as "left", "right", "front", "back", "top", "bottom", "up", and "down" in the detailed description and claims are used for illustrative purposes, if any, and are not necessarily used to describe permanent relative positions. Such terms are interchangeable under appropriate circumstances, and it should be understood that the embodiments of the devices, methods, and / or articles of manufacture described herein are capable of operating in other orientations than, for example, those illustrated or otherwise described herein. For the sake of consistency and clarity, all references to directions used herein assume that the golf club head in question is placed on a horizontally flat ground plane such that the club head's established loft and lie angles are achieved. The "front" or "front portion" of a golf club head generally refers to the side of the golf club head (when viewed perpendicular to the ground plane) that includes the strike face of the golf club head. Conversely, the rear portion of the club head is opposite the strike face and may include all of the area behind the strike face of the club head and / or portions that follow the strike face upon impact.

[0023] Terms such as "connecting", "connected", "connection", and "connecting" should be understood broadly and represent connecting two or more elements mechanically or otherwise. The connection (mechanically or otherwise) can be, for example, permanent or semi-permanent, or for any length of time such as only instantaneously.

[0024] The term "loft" or "loft angle" of a golf club described herein refers to the angle formed between the club face and the shaft, as measured by any suitable loft and lie machine.

[0025] As used herein, a "driver golf club head" has a loft angle of less than about 16 degrees, less than about 15 degrees, less than about 14 degrees, less than about 13 degrees, less than about 12 degrees, less than about 11 degrees, or less than about 10 degrees. Further, in many embodiments, a "driver golf club head" as used herein has a volume greater than about 400 cc, greater than about 425 cc, greater than about 445 cc, greater than about 450 cc, greater than about 455 cc, greater than about 460 cc, greater than about 475 cc, greater than about 500 cc, greater than about 525 cc, greater than about 550 cc, greater than about 575 cc, greater than about 600 cc, greater than about 625 cc, greater than about 650 cc, greater than about 675 cc, or greater than about 700 cc. In some embodiments, the volume of the driver can be from about 400 cc to 600 cc, from about 425 cc to 500 cc, from about 500 cc to 600 cc, from about 500 cc to 650 cc, from about 550 cc to 700 cc, from about 600 cc to 650 cc, from about 600 cc to 700 cc, or from about 600 cc to 800 cc.

[0026] As used herein, a "fairway wood golf club head" has a loft angle of less than about 35 degrees, less than about 34 degrees, less than about 33 degrees, less than about 32 degrees, less than about 31 degrees, or less than about 30 degrees. Further, in some embodiments, the loft angle of the fairway wood golf club head can be greater than about 12 degrees, greater than about 13 degrees, greater than about 14 degrees, greater than about 15 degrees, greater than about 16 degrees, greater than about 17 degrees, greater than about 18 degrees, greater than about 19 degrees, or greater than about 20 degrees. For example, in other embodiments, the loft angle of the fairway wood can be between 12 degrees and 35 degrees, between 15 degrees and 35 degrees, between 20 degrees and 35 degrees, or between 12 degrees and 30 degrees.

[0027] Furthermore, the "fairway wood golf club head" as used herein has a volume of less than about 400 cc, less than about 375 cc, less than about 350 cc, less than about 325 cc, less than about 300 cc, less than about 275 cc, less than about 250 cc, less than about 225 cc, or less than about 200 cc. In some embodiments, the volume of the fairway wood can be about 150 cc to 200 cc, about 150 cc to 250 cc, about 150 cc to 300 cc, about 150 cc to 350 cc, about 150 cc to 400 cc, about 300 cc to 400 cc, about 325 cc to 400 cc, about 350 cc to 400 cc, about 250 cc to 400 cc, about 250 cc to 350 cc, or about 275 cc to 375 cc.

[0028] The "hybrid golf club head" as used herein has a loft angle of less than about 40 degrees, less than about 39 degrees, less than about 38 degrees, less than about 37 degrees, less than about 36 degrees, less than about 35 degrees, less than about 34 degrees, less than about 33 degrees, less than about 32 degrees, less than about 31 degrees, or less than about 30 degrees. Further, in many embodiments, the loft angle of the hybrid can exceed about 16 degrees, exceed about 17 degrees, exceed about 18 degrees, exceed about 19 degrees, exceed about 20 degrees, exceed about 21 degrees, exceed about 22 degrees, exceed about 23 degrees, exceed about 24 degrees, or exceed about 25 degrees.

[0029] Furthermore, the "hybrid golf club head" as used herein has a volume of less than about 200 cc, less than about 175 cc, less than about 150 cc, less than about 125 cc, less than about 100 cc, or less than about 75 cc. In some embodiments, the volume of the hybrid can be about 100 cc to 150 cc, about 75 cc to 150 cc, about 100 cc to 125 cc, or about 75 cc to 125 cc.

[0030] As used herein, the term "decibel(s)" refers to the unit of vibration amplitude. The decibel of vibration is measured on a logarithmic scale. Due to the logarithmic nature of the decibel scale, a linear increase in the decibel value of the amplitude correlates to an exponential increase in the vibration amplitude (or "vibration energy") measured by a linear scale. Thus, a decrease and / or an increase in the decibel value of the vibration amplitude correlates to a significant decrease and / or an increase in the magnitude of the vibration amplitude, even by 1 or 2 decibels.

[0031] Other features and aspects will become apparent by considering the following detailed description and the accompanying drawings. Before any particular embodiment of the present disclosure is described in detail, it is to be understood that the present disclosure is not limited in its application to the details of components, construction, and arrangement as set forth in the following description or as illustrated in the drawings. The present disclosure is capable of supporting other embodiments and of being practiced or carried out in various ways. It is to be understood that the description of a particular embodiment is not intended to limit the present disclosure, as the description of particular embodiments is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure. Also, it is to be understood that the terminology and phraseology used herein are for the purpose of description and should not be regarded as limiting.

[0032] Schematic description of a multi-component club head Before describing the structure of the tuning element and the advantageous benefits of the tuning element that suppresses high amplitudes at the dominant natural frequency, an embodiment of a multi-component or composite clubhead structure will be described below. Refer to the drawings in which the same reference numerals identify the same or identical components in the various figures. FIGS. 1-9 schematically illustrate a multi-material wood-type golf clubhead in various views. The clubhead 100 includes a first component 120 and a second component 122. The first component 120 and the second component 122 are fixed so as to define a substantially closed / hollow internal volume. The clubhead 100 includes a striking face 102, a front end 104, a rear end 106 opposite the front end 104, a crown 108, a sole 110 opposite the crown 108, a heel end 114, and a toe end 112 opposite the heel end 114. The front end 104 of the clubhead 100 includes a striking face 102 and a leading edge 115. The clubhead 100 further includes a skirt or trailing edge 118. The skirt or trailing edge 118 is located between the crown and the sole and adjacent to the crown and the sole. The skirt extends from near the heel end 114 of the clubhead 100 to near the toe end 112.

[0033] The club head 100 is a wood-type club head such as a driver club head, a fairway wood club head, or a hybrid club head described in the present disclosure. The striking face 102 and the body 101 can define an internal cavity of the club head 100. The body 101 can extend over the outer peripheral portions of the crown 108, the sole 110, the heel end 114, the toe end 112, the rear end 106, and the front end 104. In an embodiment, the body 101 defines an opening on the front end 104 of the club head 100, and the striking face 102 is disposed within the opening so as to form the club head 100. In other embodiments, the striking face 102 can extend over the outer peripheral portion of the front end 104 and include a face return portion that extends over at least one of the crown 108, the sole 110, the heel 114, and the toe 112 (not shown). In embodiments with a striking face return portion, the return portion of the striking face 102 is fixed to the body 101 so as to form the club head 100. In these embodiments, the club head 100 can be similar to a cup face or face wrap design.

[0034] As shown in FIGS. 1-3, the club head 100 includes a hosel structure. The hosel structure 105 can receive a hosel sleeve and a golf shaft. The hosel sleeve can be connected to an end of a golf shaft (not shown). The hosel sleeve can be connected to the hosel structure in a plurality of configurations, thereby enabling the golf shaft to be fixed to the hosel structure at a plurality of angles.

[0035] The club head 100 can further include a weight port 119 configured to receive a removable weight. In many embodiments, the weight port 119 can be located on the sole 110 and / or the skirt 118. The removable weight can adjust the moment of inertia (MOI) characteristics and the center of gravity (CG) position.

[0036] The striking face 102 includes a hitting surface 103 intended to impact a golf ball. The hitting surface 103 further defines a face center or a shape center 116. In some embodiments, the face center 116 can be located at the shape center point of the hitting surface 103. In another approach, the face center 116 of the hitting surface 103 can be located according to the regulations of a golf governing body such as the United States Golf Association (USGA).

[0037] Referring to FIGS. 1-3, the club head 100 defines a ground plane 2000 that contacts the sole 110 when the club head 100 is in the address position. The face center 116 of the hitting surface 103 defines the origin of a coordinate system having an x-axis 1050, a y-axis 1060, and a z-axis 1070. The x-axis 1050 is a horizontal axis that extends in a direction from near the heel end 114 parallel to the ground plane 2000 to near the toe end 112 and passes through the face center 116. The y-axis 1060 is a vertical axis that extends in a direction from near the sole 110 perpendicular to the ground plane 2000 to near the crown 108 and passes through the face center 116. The y-axis 1060 is perpendicular to the x-axis 1050. The z-axis 1070 is a horizontal axis that extends in a direction from near the front end 104 parallel to the ground plane 2000 to near the rear end 106 and passes through the face center 116. The z-axis 1070 is perpendicular to the x-axis 1050 and the y-axis 1060. The x-axis 1050 extends in the positive direction toward the heel end 114. The y-axis 1060 extends in the positive direction toward the crown 108. The z-axis 1070 extends in the positive direction toward the rear end 106.

[0038] Referring to FIG. 6, the club head 100 further comprises a plurality of quadrants defined within a coordinate system. The club head 100 defines a front end reference plane 500. The front end reference plane 500 is in contact with the leading edge 115 at address and is orthogonal to the ground plane 2000. The club head 100 defines a rear end reference plane 600. The rear end reference plane 600 is in contact with the rear end 106 and is parallel to the front end reference plane 500. The club head 100 further defines a central plane 550 defined midway between the front end reference plane 500 and the rear end reference plane 600. The central plane 550 extends parallel to both the front end reference plane 500 and the rear end reference plane 600. When viewed from above or the crown, as shown by FIG. 6, the club head 100 defines a plurality of quadrants divided by the central plane 550 and the YZ plane. The YZ plane is defined as a plane extending along the y-axis and the z-axis. The club head 100 defines a front-toe quadrant 170, a rear-toe quadrant 172, a front-heel quadrant 174, and a rear-heel quadrant 176. The front-toe quadrant 170 is located in front of the central plane 550 and towards the toe of the YZ plane. The rear-toe quadrant 172 is located behind the central plane 550 and towards the toe of the YZ plane. The front-heel quadrant 174 is located in front of the central plane 550 and towards the heel of the YZ plane. The rear-heel quadrant 176 is located behind the central plane 550 and towards the heel of the YZ plane.

[0039] As shown in FIGS. 2 and 3, the club head 100 further includes a center of gravity (CG) 1000. In many embodiments, the center of gravity 1000 is located within the coordinate system defined above. The center of gravity 1000 is located on the x-axis 1050, the y-axis 1060, and the z-axis 1070. The center of gravity 1000 further defines the origin of a coordinate system having a CGx-axis 2050, a CGy-axis 2060, and a CGz-axis 2070. The CGx-axis 2050 extends through the CG 1000 from near the heel end 114 to near the toe end 112. The CGy-axis 2060 extends through the CG 1000 from near the crown 108 to near the sole 110, and the CGz-axis 2070 is orthogonal to the CGx-axis 2050. The CGz-axis 2070 extends through the CG 1000 from near the front end 104 to near the rear end 106 and is orthogonal to both the CGx-axis 2050 and the CGy-axis 2060.

[0040] The CGx-axis 2050 is parallel to the x-axis 1050, the CGy-axis 2060 is parallel to the y-axis 1060, and the CGz-axis 2070 is parallel to the z-axis 1070. In many embodiments, the center of gravity 1000 is preferably disposed toward the sole 110 and the rear end 106 of the club head 100.

[0041] The club head 100 further includes a moment of inertia Ixx about the CGx-axis 2050 (i.e., the crown-sole moment of inertia) and a moment of inertia Iyy about the CGy-axis 2060 (i.e., the heel-toe moment of inertia). As will be described in more detail below, increasing or maximizing the crown-sole moment of inertia Ixx and the heel-toe moment of inertia Iyy results in a club head with a high tolerance. The club head 100 includes a high moment of inertia Ixx and a high moment of inertia Iyy. The high moment of inertia Ixx and the high moment of inertia Iyy result in an improvement in the feel, tolerance, and playability of the club head 100.

[0042] First component As shown in FIGS. 1 to 4, the club head 100 can be formed from a multi-material. The club head 100 includes a first component 120 formed from a metallic material. The first component 120 has a load-bearing structure and comprises most of the mass of the club head 100 so as to withstand repeated impacts on the golf ball. The first component 120 is configured for impact on the golf ball and provides structural reinforcement to the club head 100. The first component 120 is located at the rear of the club head and includes a weight port 119 for receiving a removable weight for weight adjustment, and can include structures such as ribs that structurally reinforce the club head 100.

[0043] The first component includes a front end portion 104 having a striking face 102, a hosel structure 105, and a return portion 124 extending rearward from the outer peripheral portion of the striking face 102. In some embodiments, the first component 120 can be integrally formed as a single structure or component formed of a single material. Alternatively, the first component 120 can receive an individually formed striking face insert. The individually formed striking face insert can be fixed in an opening within the front end portion of the club head 100. The individually formed striking face insert can include a metallic material different from the metallic material of the first component.

[0044] The return portion 124 of the first component 120 forms a portion of the crown 108, sole 110, hosel structure 105, heel end 114, and toe end 112. The first component 120 further includes a sole rearward extension 160 that extends rearward of the return portion 124. The sole rearward extension 160 forms a portion of the sole 110. The sole rearward extension 160 extends between the return portion 124 and the rear end 106 of the club head 100. The sole rearward extension 160 extends for a majority of the club head length, which is measured parallel to the z-axis 1070 from the leading edge 115 to the trailing edge 118. As shown in FIGS. 3, 4A, and 4B, the sole rearward extension 160 includes a weight port 119 for weight adjustment and / or a reinforcing structure for reinforcing the club head 100.

[0045] The first component 120 of the club head 100 can be formed from, but is not limited to, steel, alloy steel, stainless steel alloy, nickel, nickel alloy, cobalt, cobalt alloy, titanium alloy, amorphous metal alloy, or other similar materials. For example, the first component 120 can be formed from, but is not limited to, Ti-8Al-1Mo-1V alloy, 17-4 stainless steel, C300, C350, Ni (nickel)-Co (cobalt)-Cr (chromium)-alloy steel, 565 steel, AISI type 304 or AISI type 630 stainless steel, 17-4 stainless steel, titanium alloy, such as, but not limited to, Ti-6-4, Ti-3-8-6-4-4, Ti-10-2-3, Ti 15-3-3-3, Ti 15-5-3, Ti185, Ti 6-6-2, Ti-7s, Ti-9s, Ti-92, T9s+, or Ti-8-1-1 titanium alloy, amorphous metal alloy, or other similar metals.

[0046] Second component The club head 100 further includes a second component 122 formed from a lightweight non-metallic material. The second component 122 reduces the mass of the crown and allows for further discretionary mass distribution to the first component 120 and / or removable weights. The second component 122 can be formed by injection molding as a single structure or component having a single material. As will be described in more detail below, the tuning element is adhered or fixed to the second component 122 to suppress high amplitudes that occur at the dominant natural frequencies.

[0047] As shown in FIGS. 1 - 4, the second component 122 forms most of the crown 108, as well as portions of the heel end 114, toe end 112, sole 110, rear end 106, and skirt 118. The second component 122 includes a crown portion 150, a sole toe portion 152a, and a sole heel portion 152b. The second component 122 is configured to be fixed to the first component 120. Referring to FIGS. 4A and 4B, the second component 122 is configured to wrap around the first component 120. The second component 122 abuts the return portion 124 and the sole rearward extension 160 of the first component 120. When viewed from the sole, the first component 120 extends between the second components 122. Specifically, the sole rearward extension 160 of the first component 120 extends between the second components 122. The second component 122 forms the heel portion 152b of the sole 110 and the toe portion 152a of the sole 110.

[0048] The second component 122 is fixed to the first component 120 at the joint surface. The second component 122 is fixed to the first component 120 at the joint surface via an adhesive or by mechanical means. The joint surface can be located at the junction between the first component 120 and the second component 122. The joint surface can be a concave lip portion. The concave lip portion extends along the outer periphery of the return portion 124 and the sole rearward extension 160. The concave lip portion is recessed from the outer surface of the club head 100 and can accommodate the combined thickness of the overlapping portions between the first component 120 and the second component 122, as well as any adhesive used to bond the two components together.

[0049] The second component 122 can be positioned within the plurality of quadrants described above. As described above, the club head 100 defines a front-toe quadrant 170, a rear-toe quadrant 172, a front-heel quadrant 174, and a rear-heel quadrant 176. A portion of the second component 122 can be positioned within the front-toe quadrant 170 and the front-heel quadrant 174. The second component 122 can be positioned entirely within the rear-toe quadrant 172 and the rear-heel quadrant 176. In other words, most of the second component 122 (i.e., the surface area of the second component 122) can be positioned behind the central plane 550. For example, more than 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or 90% of the surface area of the second component 122 can be positioned behind the central plane 550. In other embodiments, the surface area of the second component 122 positioned behind the central plane 550 can range from 55 to 95%. In yet other embodiments, the surface area of the second component 122 positioned behind the central plane 550 can range from 50% to 70%, 55% to 75%, 60% to 80%, 65% to 85%, 70% to 90%, or 75% to 95%. For example, the surface area of the second component 122 positioned behind the central plane 550 can be 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95%.

[0050] The second component 122 comprises a material having a lower density than the material of the first component 120. In some embodiments, the second component 122 may comprise a composite material formed from a polymer resin and reinforcing fibers. The polymer resin can include a thermosetting or a thermoplastic resin. The composite material of the second component 122 can be either a filled thermoplastic (FT) composite material or a fiber reinforced composite material (FRC). In some embodiments, the second component 122 can include FT joined together with FRC. The filled thermoplastic (FT) composite material is typically injection molded into a desired shape. The filled thermoplastic (FT) composite material can include a thermoplastic resin and randomly oriented discontinuous fibers. In contrast, the fiber reinforced composite material (FRC) is formed from a resin-impregnated (prepreg) continuous fiber sheet. The fiber reinforced composite material (FRC) can include either a thermoplastic resin or a thermosetting resin.

[0051] In embodiments using a thermoplastic resin, the resin can include a thermoplastic polyurethane (TPU) or a thermoplastic elastomer (TPE). For example, the resin can include polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyimide, a polyamide such as PA6 or PA66, polyamide-imide, polyphenylene sulfide (PPS), polycarbonate, engineering polyurethane and / or other similar materials. Strength and weight are two main characteristics when considering composite materials, but suitable composite materials can also exhibit secondary benefits such as acoustic properties. In some embodiments, PPS and PEEK are desirable because they generally produce an acoustic response with a sound like that of metal upon impact of the club head.

[0052] The reinforcing fibers can include carbon fibers (or chopped carbon fibers), glass fibers (or chopped glass fibers), graphite fibers (or chopped graphite fibers), or any other suitable filler material. In other embodiments, the composite material can include any reinforcing filler that adds strength, durability and / or weight.

[0053] The density of the composite material (combining resin and fiber) forming the second component 122 can range from about 1.15 g / cc to about 2.02 g / cc. In some embodiments, the density of the composite material ranges between about 1.20 g / cc and about 1.90 g / cc, between about 1.25 g / cc and about 1.85 g / cc, between about 1.30 g / cc and about 1.80 g / cc, between about 1.40 g / cc and about 1.70 g / cc, between about 1.30 g / cc and about 1.40 g / cc, or between about 1.40 g / cc and about 1.45 g / cc.

[0054] Material of the second component - filled thermoplastic (FT) material In the FT material, the polymer resin should preferably incorporate one or more polymers having sufficiently high material strength and / or strength / weight ratio characteristics so as to withstand typical use and provide weight savings benefits to the design. Specifically, for the design and the material, it is important to efficiently withstand the stress imparted during the impact between the strike face and the golf ball and not substantially contribute to the total weight of the golf club head. Generally, the polymer can be characterized by a yield point tensile strength exceeding about 60 MPa (net). When the polymer resin is combined with reinforcing fibers, the resulting composite material can have a yield point tensile strength exceeding about 110 MPa, exceeding about 180 MPa, exceeding about 220 MPa, exceeding about 260 MPa, exceeding about 280 MPa, or exceeding about 290 MPa. In some embodiments, a suitable composite material can have a yield point tensile strength ranging from about 60 MPa to about 350 MPa.

[0055] In some embodiments, the reinforcing fibers include a plurality of dispersed discontinuous fibers (i.e., chopped fibers). In some embodiments, the reinforcing fibers include discontinuous "long fibers" having a designed fiber length of from about 3 mm to 25 mm. In some embodiments, the discontinuous "long fibers" have a designed fiber length of from about 3 mm to 14 mm. For example, in some embodiments, the fiber length is about 12.7 mm (0.5 inch) before the molding process. In some embodiments, the reinforcing fibers include discontinuous "short fibers" having a designed fiber length of from about 0.01 mm to 3 mm. In any case (whether short fibers or long fibers), the given length is a pre-mixed length, and it should be noted that for some fibers, due to breakage during the molding process, they may actually be shorter than the above range in the final component. In some configurations, the discontinuous chopped fibers can be characterized by an aspect ratio (e.g., fiber length / diameter) of greater than about 10, or more preferably greater than about 50 and less than about 1500. Regardless of the specific type of discontinuous chopped fibers used, in a particular configuration, the composite material can have a fiber length of from about 0.01 mm to about 25 mm, or from about 0.01 mm to about 14 mm.

[0056] The composite material can have a polymer resin content of from about 40 wt% to about 90 wt%, or a polymer resin content of from about 55 wt% to about 70 wt%. The second component of the composite material can have a fiber content between about 10 wt% and about 60 wt%. In some embodiments, the composite material has a fiber content between about 20 wt% and about 50 wt%, or between 30 wt% and 40 wt%. In some embodiments, the composite material has a fiber content between about 10 wt% and about 15 wt%, between about 15 wt% and about 20 wt%, between about 20 wt% and about 25 wt%, between about 25 wt% and about 30 wt%, between about 30 wt% and about 35 wt%, between about 35 wt% and about 40 wt%, between about 40 wt% and about 45 wt%, between about 45 wt% and about 50 wt%, between about 50 wt% and about 55 wt%, or between about 55 wt% and about 60 wt%.

[0057] In an embodiment where the second component 122 comprises a filler-containing thermoplastic (FT) material, the second component 122 can be injection molded from composite pellets that include both a polymer resin and reinforcing fibers. The reinforcing fibers can be embedded within the resin prior to the injection molding process. The pellets can be melted to form the second component 122 and injected into an empty mold. The FT composite material can have a melting temperature between about 210°C and about 280°C. In some embodiments, the composite material can have a melting temperature between about 250°C and about 270°C.

[0058] In embodiments with the second component 122 of the FT material, at least 50% of the fibers can be aligned generally front-to-back within the central region of the crown 108. In other words, the fibers can be aligned generally orthogonal to the striking face 102. The FT material exhibits maximum strength in the fiber alignment direction. Thus, by orienting the fibers generally in the front-to-back direction, the durability of the club head 100 is increased. The fibers can be oriented generally in the front-to-back direction to counter the compressive stresses within the crown 108 that occur during impact of the golf ball. The alignment of the fibers can correspond to the flow direction of the material within the mold during the injection molding process.

[0059] In some embodiments, the second component 122 can be formed from a long fiber reinforced TPU material (exemplary FT material). The long fiber TPU can include about 40 wt% long carbon fibers. The long fiber TPU can exhibit a modulus of elasticity higher than that of a short carbon fiber compound. The long fiber TPU can withstand high temperatures and is suitable for use in golf club heads used and / or stored in hot climates. The long fiber TPU further exhibits high toughness and enables it to function well as an alternative to conventional metal components. In some embodiments, the long fiber TPU includes a tensile coefficient between about 26,000 MPa and about 30,000 MPa, or between about 27,000 MPa and about 29,000 MPa. In some embodiments, the long fiber TPU includes a flexural modulus of elasticity between about 21,000 MPa and about 26,000 MPa, or between about 22,000 MPa and about 25,000 MPa. The long fiber TPU material can have a (breaking point) tensile elongation between about 0.5% and about 2.5%. In some embodiments, the tensile elongation of the composite TPU material can be between about 1.0% and about 2.0%, between about 1.2% and about 1.4%, between about 1.4% and about 1.6%, between about 1.6% and about 1.8%, between about 1.8% and about 2.0%.

[0060] Material of the second component - fiber reinforced composite (FRC) In some embodiments, the second component 122 can include a fiber reinforced composite (FRC) material. The FRC material can generally include one or more layers of unidirectional or multi-directional fiber fabrics extending over a larger portion of the polymer. Unlike the reinforcing fibers that can be used in filled thermoplastic (FT) materials, the maximum dimension of the fibers used in FRC can be substantially larger / longer than the maximum dimension used in FT materials and can have sufficient size and properties to be provided as a continuous fabric separate from the polymer. When formed with a thermoplastic polymer, even when the polymer is freely flowable when melted, the continuous fibers included generally do not flow. The reinforcing fibers can include a basis weight (weight per length×width area) between 75 g / m2 and 150 g / m2.

[0061] FRC materials are generally formed by arranging fibers in a desired configuration and then impregnating the fiber material with a sufficient amount of polymer material to provide sufficient rigidity. Thus, while FT materials can have a resin content of more than about 45% by volume, or more preferably more than about 55% by volume, FRC materials can desirably have a resin content of less than about 45% by volume, or more preferably less than about 35% by volume. In some embodiments, the resin content of the FRC can be between 24% and 45% by volume.

[0062] Conventionally, FRC materials use a two-component thermosetting epoxy as the polymer matrix, but it is also possible to use a thermoplastic polymer as the matrix. In many cases, FRC materials are pre-prepared before final manufacture, and such intermediate materials are often referred to as prepregs. When using a thermosetting polymer, the prepreg is partially cured in an intermediate form, and final curing occurs when the prepreg is formed into its final shape. When using a thermoplastic polymer, the prepreg can include a cooled thermoplastic matrix. The thermoplastic matrix can then be heated and formed into its final shape.

[0063] The second component 122 of the FRC can comprise a plurality of layers (also referred to as a plurality of thin layers). Each layer can include and / or be the same thickness as the prepreg. Each of the plurality of layers can comprise either a unidirectional fiber cloth (UD) or a multi-directional fiber cloth (sometimes referred to as a woven cloth). In some embodiments, the plurality of layers can comprise at least three UD layers. The second and third layers can be angled with respect to a reference layer. When the reference layer is oriented at 0 degrees, the second and third layers can be oriented at ±45 degrees from the reference layer. In some embodiments, the layers can be oriented at 0, +45, -45, +90, -90 in any suitable order. In some embodiments, the plurality of layers comprises at least one multi-directional woven cloth layer, and at least one multi-directional woven cloth layer is typically disposed in the upper layer to improve the appearance of the second component 122 of the FRC.

[0064] Material of the second component - hybrid material The second component 122 can have a hybrid material structure that includes both a fiber-reinforced composite elastic layer and a molded thermoplastic structural layer. In some preferred embodiments, the molded thermoplastic structural layer can be formed from a filler-containing thermoplastic (FT) material. As noted above, the FT can include discontinuous glass, carbon, or aramid polymer fiber fillers embedded throughout the thermoplastic material. The thermoplastic resin can be, for example, a TPU such as polyphenylene sulfide (PPS), polyether ether ketone (PEEK), or a polyamide such as PA6 or PA66. The fiber-reinforced composite elastic layer can include a woven glass, carbon fiber, or aramid polymer fiber reinforcement layer embedded within a polymer resin (or matrix). The polymer resin of the elastic layer can be thermoplastic or thermosetting.

[0065] In some embodiments, the polymer resin of the fiber-reinforced composite elastic layer is the same thermoplastic material as the resin of the molded thermoplastic structural layer. In other words, the fiber-reinforced elastic layer and the molded structural layer can include a common thermoplastic resin. Forming the elastic layer and the structural layer from a common thermoplastic resin enables a strong chemical bond between the layers. In these embodiments, the elastic layer and the structural layer can be joined without using an intermediate adhesive. In one particular embodiment, the elastic layer of the second component 122 can include a woven carbon fiber fabric embedded within polyphenylene sulfide (PPS), and the structural layer of the second component (122) can include a filled polyphenylene sulfide (PPS) polymer. In an alternative embodiment, the second component 122 can be formed by extrusion molding, injection blow molding, 3-D printing, or other suitable forming means.

[0066] Tuning element The above-described multi-material club head 100 may further include a tuning element 130. The multi-material club head includes considerations for various sounds or acoustic responses as compared to the acoustic response of a full-metal club head. The tuning element 130 can be positioned on the lightweight non-metallic second component 122 to provide a desired acoustic response and a desired "softer" feel to the multi-material club head 100.

[0067] As described below and with reference to FIGS. 4A-9, the tuning element 130 improves the sound and feel characteristics of the club head 100 by suppressing prominent vibrations. In some embodiments, the club head 100 reduces the prominent vibration amplitude between 1 and 7 decibels as compared to a similar multi-material club head without a tuning element. The club head 100 includes excellent sound control and minimizes the impact on the position of the center of gravity 1000 and the moment of inertia of the club head.

[0068] The tuning element 130 is disposed at a target location for controlling vibration and sound. The tuning element 130 suppresses the dominant vibration amplitude of an impact that results in an undesirable sound or feel in the club head 100. The tuning element 130 can be located at a portion of the club head 100 that receives the dominant vibration and can suppress such undesirable vibrations. The tuning element 130 serves to locally suppress the vibration amplitude. Otherwise, this vibration amplitude would occur if the tuning element 130 were not provided at the target location. In many embodiments, the tuning element 130 targets high amplitude vibrations at frequencies above 5000 Hz. The club head 100 may include a maximum amplitude of up to 70 decibels at a given frequency, and with the tuning element 130 included, the amplitude can be reduced by 1 to 7 decibels. By specifically targeting the location where the most significant vibrations due to impact occur (i.e., the vibration “hot spot” 140 of the club head 100) and disposing the tuning element 130 at the hot spot 140, the tuning element 130 requires a relatively low mass to provide the same damping effect as a higher mass tuning element located away from the hot spot 140. Thus, the sound and feel of the club head 100 can be improved by the use of only a lightweight tuning element 130 that does not adversely affect the mass characteristics of the club head 100.

[0069] In many embodiments, as shown in FIG. 4B, the tuning element 130 is disposed on the second impact 122. More particularly, the tuning element 130 can be disposed on a portion 150 of the second impact 122 that forms a majority of the crown 108 of the club head 100, on the opposite side of the toe portion 152a or the heel portion 152b of the second impact 122. In many embodiments, the tuning element 130 can be located on the inner surface 127 of the crown 108. In many embodiments, the tuning element 130 is disposed in the rear heel portion of the crown 108. In many other embodiments, the tuning element 130 is disposed in the rear toe portion of the crown 108. The position of the tuning element on the crown 108 can correspond to the position of the vibration hot spot 140.

[0070] The tuning element 130 can be easily coupled to the inner surface 127 of the second impact 122. As shown in FIGS. 4A and 4B, the multi-component nature of the club head 100 allows for the easy attachment of the tuning element 130 to the inner surface of the second impact 122. This is because the tuning element 130 can be attached to the second component 122 before the internal cavity 128 is sealed. As described above, in the case of a multi-component club head structure, the second component 122 is fixed to the first component 120 via an adhesive or mechanical means without using a heat source. The tuning element 130 can be attached before the second component 122 is fixed to the first component 120. This is because there is no heating step associated with the fixing of the components 120, 122 that would compromise the structural integrity of the tuning element 130.

[0071] The tuning element 130 is a lightweight member that can be attached to a portion of the club head 100 (e.g., the inner surface 127 of the second component 122) so as to suppress and dissipate the dominant vibration. In many embodiments, the tuning element 130 can be attached to the inner surface 127 of the second component 122 through the use of adhesives, epoxies, etc. The tuning element 130 can comprise a plurality of layers formed from various materials. The tuning element 130 can have a three-layer structure or a two-layer structure.

[0072] In many embodiments, as shown by FIG. 5, the tuning element 130 has a three-layer structure. As shown by FIG. 5, the tuning element comprises an adhesive layer 134, a reinforcing layer 138 on the opposite side of the adhesive layer 134, and a damping layer 136 sandwiched between the adhesive layer 134 and the reinforcing layer 138. The adhesive layer 134 forms the bottom surface of the tuning element 130 and can function to adhere the tuning element 130 to the inner surface 127 of the second component 122. In such three-layer embodiments, the damping layer 136 can include a viscoelastic polymer configured to dissipate vibration by converting kinetic energy into heat. The damping layer can include any viscoelastic polymer or material such as elastomers, butyl rubber, silicone rubber, thermoplastic elastomer (TPE), thermoplastic polyurethane (TPU), or other suitable materials with viscoelastic properties.

[0073] In many embodiments, the reinforcing layer 138 comprises a thin layer of a material with high tensile strength so as to impart rigidity to the tuning element 130 without contributing a significant amount of mass to the tuning element 130. In many embodiments, the reinforcing layer 138 can be formed from a polymer material, a composite material, or a glass cloth. In some embodiments, the reinforcing layer 138 can include a fiber-reinforced composite material such as woven glass, carbon fiber, or an aramid polymer fiber reinforcement layer embedded in a polymer resin. In alternative embodiments, the reinforcing layer 138 can include a lightweight metal material such as aluminum, aluminum foil, aluminum alloy, titanium, titanium alloy, magnesium, or magnesium alloy.

[0074] As described above, the reinforcing layer 138 includes a high tensile strength that gives rigidity to the tuning element 130. In many embodiments, the tensile strength of the reinforcing layer 138 can be greater than about 60 MPa, greater than about 110 MPa, greater than about 180, greater than about 220 MPa, greater than about 260 MPa, greater than about 280 MPa, or greater than about 290 MPa. In some embodiments, a suitable composite material can have a yield point tensile strength from about 60 MPa to about 350 MPa.

[0075] The club head 100 bends and vibrates upon impact with a golf ball. Similarly, the reinforcing layer 138 also bends and vibrates upon impact. The bending and vibration of the second component 122 and the reinforcing layer 138 apply shear forces onto the damping layer 136 confined between the inner surface 127 of the second component 122 and the reinforcing layer 138. The shear forces generated by the vibration stretch the viscoelastic material within the damping layer 136. The viscoelasticity of the damping layer 136 converts the kinetic energy of the vibration into thermal energy. In this way, the tuning element 130 dissipates the vibration energy generated at the hot spot 140.

[0076] In other embodiments (not shown), the tuning element 130 comprises a two-layer structure. The two-layer structure of the tuning element 130 in some embodiments can be similar to the three-layer structure of other embodiments, except that the two-layer structure may lack the reinforcing layer 138. In many embodiments, the two-layer structure of the tuning element 130 can simply comprise an adhesive layer 134 and a damping layer 136. In such embodiments, the damping layer 136 is exposed to the internal cavity 128 of the club head 100 and is not confined by the reinforcing layer 138. In such embodiments, the damping layer 136 may or may not be a viscoelastic polymer as described above. In addition to the polymers listed above, the damping layer 136 of the two-layer structure can alternatively be formed of other materials having damping characteristics, such as foams, acrylic foams, felts, or polymer-based glues.

[0077] In an alternative embodiment, the tuning element 130 can be any lightweight material attachable to the club head 100 for damping. In some embodiments, the tuning element 130 can be a polymer-based tape such as Very High Bond (VHB) tape, or other high-bonding tape that can be joined to the non-metallic second component 122. In other embodiments, the tuning element 130 can be a polymer-based glue. In some embodiments, the tuning element 130 can include a polymer or polymer glue encapsulated within a protective layer such as a plastic layer that is joined to the second component 122 by an adhesive. In some embodiments, the tuning element 130 can comprise one or more tape layers, one or more adhesive layers, one or more epoxy layers, one or more foam layers, one or more viscoelastic layers, one or more felt layers, one or more composite material layers, one or more polymer layers, one or more glue layers, one or more glass fiber layers, or combinations thereof.

[0078] The tuning element 130 can be a lightweight element having a low density that provides a small amount of mass compared to the overall mass of the club head 100. In this way, the addition of the tuning element 130 to the club head 100 does not significantly affect the overall mass of the club head or the mass characteristics of the club head 100, including the moment of inertia (MOI) and the center of gravity (CG) position.

[0079] The tuning element 130 has a low density in the range between 0.5 g / cm 3 ~ 2 g / cm 3 . In some embodiments, the density of the tuning element 130 is between 0.5 g / cm 3 ~ 1.0 g / cm 3 , between 0.75 g / cm 3 ~ 1.25 g / cm 3 , between 1.0 g / cm 3 ~ 1.5 g / cm 3 , between 1.25 g / cm 3 ~ 1.75 g / cm 3 or between 1.5 g / cm3 ~2.0 g / cm 3 can take a range between. In some embodiments, the density of the tuning element 130 is 0.5 g / cm 3 ~1.5 g / cm 3 between, 0.6 g / cm 3 ~1.6 g / cm 3 between, 0.7 g / cm 3 ~1.7 g / cm 3 between, 0.8 g / cm 3 ~1.8 g / cm 3 between, 0.9 g / cm 3 ~1.9 g / cm 3 between, or 1.0 g / cm 3 ~2.0 g / cm 3 between. In some embodiments, the density of the tuning element 130 is about 0.5 g / cm 3 , 0.6 g / cm 3 , 0.7 g / cm 3 , 0.8 g / cm 3 , 0.9 g / cm 3 , 1.0 g / cm 3 , 1.1 g / cm 3 , 1.2 g / cm 3 , 1.3 g / cm 3 , 1.4 g / cm 3 , or 1.5 g / cm 3 can be.

[0080] The tuning element 130 has a mass between 0.5 grams and 10 grams. In many embodiments, the mass of the tuning element 130 can be between 0.5 grams and 8 grams, between 0.5 grams and 6 grams, or between 0.5 grams and 4 grams. In some embodiments, the mass of the tuning element 130 can be between 0.5 grams and 10 grams, between 0.5 grams and 8 grams, between 0.5 grams and 6 grams, between 0.5 grams and 4 grams, or between 0.5 grams and 2.0 grams. In some embodiments, the mass of the tuning element 130 can be between 2 grams and 10 grams, between 2 grams and 8 grams, between 2 grams and 6 grams, or between 2 grams and 5 grams. In many embodiments, the mass of the tuning element 130 can be about 0.5 grams, about 1 gram, about 1.5 grams, about 2 grams, about 2.5 grams, or about 3 grams.

[0081] Despite its light weight, the tuning element 130 provides a significant damping effect on the golf club head 100. As will be described in more detail below, the tuning element 130 can suppress the vibration amplitude generated at a frequency exceeding 5000 Hz by 1 to 7 decibels. The light weight of the tuning element 130 makes it possible to produce a damping effect without significantly modifying the mass characteristics of the club head 100.

[0082] Arrangement of the tuning element As described above, the tuning element 130 is preferably positioned at the target location of the club head body 100 so as to effectively suppress unwanted vibrations without requiring a large mass. The position of the tuning element 130 corresponds to the position of the vibration hot spot 140 of the club head 100. As described above, referring to FIG. 7, the hot spot 140 is defined herein as the position on the club head 100 that receives the maximum vibration amplitude at the natural frequency of the club head 100. The hot spot 140 is defined based on the vibration response of the club head 100. The tuning element 130 is aligned with the hot spot 140. The hot spot 140 is the region of the club head 100 that includes the most significant vibrations relative to the overall acoustic response of the club head 100 and is often a contributor to annoying and / or thumping sounds. By determining the position of the hot spot 140 and disposing the tuning element 130 at the hot spot 140, such significant vibrations can be suppressed and the overall acoustic response of the club head 100 can be improved (i.e., the sound of the club head 100 is made weaker, quieter, and / or duller). In some embodiments, the position of the tuning element 130 can correspond to one or more quadrants in which the hot spot is located. In other embodiments, the position of the tuning element 130 can correspond to one or more vibration position features 185 disposed on the crown 108, as will be described in more detail below.

[0083] The position of the hot spot 140 can be determined by performing a routine modal analysis on the club head 100. Through such an analysis, one or more natural frequencies of the club head 100 and the "shape" of each natural frequency (i.e., the vibration amplitudes within various regions of the club head 100 at a given natural frequency) are determined. The position of the vibration hot spot 140 can be identified by determining the region of the highest vibration amplitude within the club head at a given natural frequency.

[0084] In many embodiments, the club head 100 has a natural frequency in the range between 5000 Hz and 6500 Hz. In some embodiments, the club head 100 can have a natural frequency between 3000 Hz and 4000 Hz, between 3500 Hz and 4500 Hz, between 4000 Hz and 5000 Hz, between 4500 Hz and 5500 Hz, between 5000 Hz and 6000 Hz, between 5500 Hz and 6500 Hz, or between 6000 Hz and 7000 Hz. In some embodiments, the club head 100 can have a natural frequency in the range between 3000 Hz and 3500 Hz, between 3500 Hz and 4000 Hz, between 4000 Hz and 4500 Hz, between 4500 Hz and 5000 Hz, between 5000 Hz and 5500 Hz, between 5500 Hz and 6000 Hz, between 6000 Hz and 6500 Hz, or between 3000 Hz and 4000 Hz.

[0085] FIG. 7 shows the vibration amplitudes at various positions on the club head at a given natural frequency determined through modal analysis. The darker shaded regions of the figure correspond to regions with greater vibration amplitudes. As shown by FIG. 7, the hot spot 140 occurs within the rear - heel quadrant 176 of the club head 100. The tuning element 130 can be placed at a position corresponding to the hot spot 140 so as to suppress (i.e., reduce the dominant vibration amplitude) the dominant vibrations occurring at the hot spot 140 and in its surrounding area. By placing the tuning element 130 directly at the position corresponding to the hot spot 140, the tuning element 130 provides more effective vibration damping for the dominant vibrations occurring at the hot spot 140 than tuning elements placed at other positions. By accurately placing the tuning element 130 at the position corresponding to the hot spot 140, it is possible for the tuning element 130 to provide a significant vibration damping effect without requiring a significant amount of mass.

[0086] The high vibration amplitude that occurs at the above frequency (for example, a frequency between 5000 Hz and 6500 Hz) causes an undesirable acoustic response within the golf club head 100 upon impact. In many embodiments, prior to applying the tuning element 130, the maximum vibration amplitude at a given frequency may be greater than about 66 decibels, greater than 67 decibels, greater than 68 decibels, greater than 69 decibels, greater than 70 decibels, greater than 71 decibels, or greater than 72 decibels.

[0087] The tuning element 130 provides a significant damping effect that reduces the dominant vibrations occurring at the hot spot 140. In some embodiments, the tuning element 130 can reduce the maximum amplitude at the natural frequency by 1 to 7 decibels. In some embodiments, the tuning element 130 can reduce the maximum amplitude of the natural frequency by 1 decibel to 3 decibels, 2 decibels to 4 decibels, 3 decibels to 5 decibels, 4 decibels to 6 decibels, or 5 decibels to 7 decibels. In some embodiments, the tuning element 130 can reduce the maximum amplitude of the natural frequency by more than 1 decibel, more than 2 decibels, more than 3 decibels, more than 4 decibels, more than 5 decibels, more than 6 decibels, or more than 7 decibels.

[0088] Since the decibel scale is a logarithmic representation of amplitude, even a decrease of 1 or 2 decibels correlates to a significant decrease in vibration energy. As an example of a logarithmic representation of amplitude, Table 1 below relates the linear magnitude of the vibration energy received by the golf club 100 to the decibel values associated with the typical peak amplitude received by the golf club head 100.

Table 1

[0089] As can be seen from Table 1, a 1 decibel decrease in amplitude (e.g., a decrease between 70 decibels and 69 decibels) results in a 10.9% decrease in vibration energy. Similarly, for example, a 6 decibel decrease in amplitude (i.e., a decrease between 70 decibels and 64 decibels) results in a 50% decrease in vibration energy. Similarly, a 10 decibel decrease in amplitude (e.g., a decrease from 70 decibels to 60 decibels) corresponds to a 68% decrease in vibration energy. Such a significant decrease in vibration energy at a given natural frequency (i.e., a natural frequency above 5000 Hz) results in a significant improvement in the acoustic response of the club head 100.

[0090] In some embodiments, the club head 100 may include a plurality of hot spots 140 at various positions at the same natural frequency or at different natural frequencies. In such embodiments, the club head may comprise a first tuning element 130 corresponding to the position of the first hot spot 140 and a second tuning element (not shown) corresponding to the position of the second hot spot 140. As shown in FIG. 7, the club head 100 includes a first hot spot 140 located in the rear - heel quadrant 176 and a second hot spot 140 located in the rear - toe quadrant 172.

[0091] As shown in FIG. 6, the position of the tuning element 130 can be characterized in relation to the quadrant system of the club head 100. In many embodiments, the tuning element is located in the rear - heel quadrant. In other embodiments, the tuning element 130 can be located in the front - toe quadrant 170, the rear - toe quadrant 172, the front - heel quadrant 174, the rear - heel quadrant 176, or a combination thereof. In some embodiments, the tuning element 130 can be located within only a single quadrant, such as within only the front - toe quadrant 170, within only the rear - toe quadrant 172, within only the front - heel quadrant 174, or within only the rear - heel quadrant 176. In some embodiments, the tuning element 130 can be at least partially located within the front - toe quadrant 170, at least partially located within the rear - toe quadrant 172, at least partially located within the front - heel quadrant 174, and / or at least partially located within the rear - heel quadrant 176. In many embodiments, as shown in FIG. 6, a portion of the tuning element 130 can be located within the rear - heel quadrant 176 and a portion of the tuning element can be located within the front - heel quadrant 174. In many other embodiments, the tuning element can be partially located within the rear - toe quadrant 172 and partially located within the front - toe quadrant 170.

[0092] The position of tuning element 130 can be further characterized in relation to the center position of the tuning element. As shown in FIG. 6, tuning element 130 can define a tuning element center point 132 midway between the outer peripheral edges of tuning element 130. Tuning element center point 132 is located at half of the heel-to-toe distance between the most heel point or edge of tuning element 130 and the most toe point or edge of tuning element 130. Similarly, tuning element center point 132 is located at half of the front-to-back distance between the most front point or edge of tuning element 130 and the most rear point or edge of tuning element 130. Tuning element 130 can be rectangular, circular, elliptical, or any other shape or geometric form. Regardless of the shape of tuning element 130, center point 132 is defined as the midpoint between the most heel range and the most toe range of tuning element 130, and as the midpoint between the most front range and the most rear range of tuning element 130.

[0093] Furthermore, the position of tuning element 130 can be described in relation to the quadrant in which tuning element center point 132 lies. In many embodiments, as shown in FIG. 6, tuning element center point 132 is located within the rear-heel quadrant 176. In other embodiments, tuning element center point 132 can be located within the front-toe quadrant 170, the rear-toe quadrant 172, or the front-heel quadrant 174.

[0094] The position of the tuning element 130 can be further described in relation to the front-end reference plane 500 and the tuning element center point 132 in terms of a forward-backward or offset distance D1. The offset distance D1 is a vertical distance measured in the direction of the z-axis 1070 from the front-end reference plane 500 to the tuning element center point 132. In some embodiments, the offset distance D1 between the front-end reference plane 500 and the tuning element center point 132 can be between about 1.5 inches and 2.5 inches. In some embodiments, the offset distance D1 between the front-end reference plane 500 and the tuning element center point 132 can be between about 1.5 inches and 2.0 inches, between 1.75 inches and 2.25 inches, or between 2.0 inches and 2.5 inches. In some embodiments, the offset distance D1 between the front-end reference plane 500 and the tuning element center point 132 can be between 1.5 inches and 1.7 inches, between 1.6 inches and 1.8 inches, between 1.7 inches and 1.9 inches, between 1.8 inches and 2.0 inches, between 1.9 inches and 2.1 inches, between 2.0 inches and 2.2 inches, between 2.1 inches and 2.3 inches, between 2.2 inches and 2.4 inches, or between 2.3 inches and 2.5 inches. In some embodiments, the offset distance D1 between the front-end reference plane 500 and the tuning element center point 132 can be about 1.7 inches, about 1.8 inches, about 1.9 inches, about 2.0 inches, about 2.1 inches, about 2.2 inches, or about 2.3 inches.

[0095] In some embodiments, the club head can further include one or more physical features that affect the location of the club head vibration hot spot 140. FIGS. 8A and 8B illustrate one embodiment of a multi-component club head 100 having a plurality of location features 185 on the crown 108. The plurality of location features 185 can each form a concave region 186 on the outer surface of the crown 108. Each location feature 185 can include an edge 188 that separates the concave region 186 from an adjacent non-concave region of the crown 108. The location feature 185 affects the location of the hot spot by introducing a discontinuity into the surface of the crown 108 that would otherwise be smooth and uniform in shape. Such a discontinuity is the common area where the vibration hot spot 140 occurs. This discontinuity results in a slightly weakened region within the crown 108 that tends to vibrate more than other regions. As shown by FIG. 8B, the hot spot 140 of the multi-material club head 100 occurs in proximity to the location feature 185. Incorporating the location feature 185 within the crown 108 of the club head 100 reduces the variation in the location of the hot spot 140 between clubs. Thus, the hot spot is more precisely and repeatedly located during manufacturing by including the location feature 185. The ability to accurately and repeatedly locate the hot spot results in a more accurate and effective placement of the tuning element 130.

[0096] In addition to providing control related to the position of the hot spot 140, the position feature 185 serves two roles as a natural alignment feature on the inner surface 127 of the crown 108, enabling an accurate and repeatable placement of the tuning element 130 during manufacturing. As shown in FIG. 9, the edge 188 of the position feature 185 extends from the inner surface 127 of the second component 122 into the internal cavity 128, and the recessed region 186 on the outer surface of the club head 100 can form a protrusion 180 from the inner surface 127 into the internal cavity 128. The protrusion 180 acts as an alignment feature that visually indicates the desired position of the tuning element 130. The protrusion 180 can form a surface for adhering the tuning element 130, and the edge 188 can align the direction of the placement of the tuning element.

[0097] As described above, the position feature 185 affects the hot spot 140 such that it is positioned at a specific location on the crown 108. The position feature 185 also forms a protrusion 180 that acts as an alignment feature that aligns with the same position on the inner surface 127 of the crown 108 as the position corresponding to the hot spot 140. Since the protrusion 180 is associated with the position of the hot spot 140, the tuning element 130 can be repeatedly and accurately aligned with the protrusion 180 at the precise position necessary to effectively suppress the vibrations occurring at the hot spot 140.

[0098] Further sound benefits Including the tuning element 130 can, in addition to suppressing the dominant vibration amplitude, affect the amount of time the club head 100 vibrates after impact. The tuning element 130 can reduce the total duration of the vibration response and the duration during which high-amplitude vibrations occur. The total duration of the vibration response can be separated into a "maintenance" phase and a "release" phase. The maintenance phase refers to the time interval that starts at impact and ends when the response falls below 20% of the maximum amplitude value. The maintenance phase characterizes the amount of time during which dominant vibrations occur. When the vibration response includes a relatively long maintenance phase, the sound at impact is perceived as a more annoying sound. In contrast, reducing the duration of the maintenance phase weakens the perceived sound at impact, even when the maximum amplitude remains the same. The release phase refers to the time interval that starts when the vibration response falls below 20% of the maximum amplitude (i.e., at the end of the maintenance phase) and ends when the club head 100 stops vibrating. The release phase characterizes the amount of time during which less vibration occurs. Extending the release phase can impart a "ringing" sensation to the club head 100. As will be described below by way of various examples, including the tuning element 130 reduces both the maintenance and release phase durations (and thus the total duration) of the vibration response of the club head 100, producing a more pleasant sound at impact.

[0099] In many prior art club heads without a tuning element, the total duration of the vibration response can range from about 36 milliseconds to about 40 milliseconds, the maintenance duration can range from about 8 milliseconds to about 12 milliseconds, and the release duration can range from about 27 milliseconds to about 31 milliseconds. In many embodiments, including the tuning element 130 can reduce the total duration of the vibration response by more than 1 millisecond, more than 2 milliseconds, more than 3 milliseconds, more than 4 milliseconds, more than 5 milliseconds, more than 6 milliseconds, more than 7 milliseconds, more than 8 milliseconds, more than 9 milliseconds, or more than 10 milliseconds. Reducing the vibration response duration weakens the acoustic response and reduces the ringing after impact.

[0100] Characteristics of the center of gravity and moment of inertia The precise placement of the tuning element 130 relative to the vibration hot spot 140 of the club head 100 results in significant vibration damping and acoustic improvement, and also allows the tuning element 130 to contain a small amount of mass. The lightweight nature of the tuning element 130 allows the tuning element 130 to be placed at a specific location on the crown 108 without adversely affecting the characteristics of the club head 100 such as the moment of inertia characteristics or the position of the center of gravity 1000.

[0101] Considerations involved in the placement of the tuning element 130 (i.e., the placement of the crown) often add mass to the crown 108 and may adversely affect the characteristics of the center of gravity (CG) and moment of inertia (MOI). However, the club head 100 with the lightweight tuning element 130 can further include a beneficial position of the center of gravity 1000 and increased moment of inertia characteristics. The multi-component club head 100 with the lightweight tuning element 130 can further include a low rearward center of gravity 1000 position. The multi-component club head 100 with the lightweight tuning element 130 can further include high moments of inertia Ixx and Iyy. The multi-component club head 100 with the lightweight tuning element 130, the low rearward center of gravity 1000 position, and the high moment of inertia provides excellent sound control, feel, and playability to the club head 100.

[0102] To achieve a beneficial center of gravity 1000 position and a high moment of inertia, the club head 100 can further include structures that affect the mass characteristics of the club head, such as a removable weight 119, a thin-walled crown 108 formed from a non-metallic material, and / or a lightweight crown 108. These structures allow for adjustment of the mass characteristics to achieve a low rear CG position and high moment of inertia characteristics. These structures can enable weight adjustment or weight savings in combination with crown tuning elements 130 that provide sound control. The crown tuning elements 130 do not adversely affect the center of gravity 1000 and moment of inertia characteristics. The crown tuning elements 130 minimize the effect on the position of the center of gravity 1000 (i.e., minimize the forward movement of the CG towards the front end 104 and upward movement towards the crown 108), and minimize the effect on the moment of inertia (i.e., the difference in MOI percentage between the club head 100 with the tuning element 130 and the club head without the tuning element is minimal). The crown tuning elements 130 have a minimal effect on the center of gravity 1000 and moment of inertia characteristics, and provide a significant sound control benefit compared to similar club heads without the tuning element 130.

[0103] As described above, referring to FIGS. 2 and 3, the center of gravity 1000 is located within a coordinate system defined by the face center 116 having an x-axis 1050, a y-axis 1060, and a z-axis 1070. The x-axis 1050 extends in the positive direction towards the heel end. The y-axis 1060 extends in the positive direction towards the crown. The z-axis 1070 extends in the positive direction towards the rear end 106. The club head 100 preferably includes a "lower rear" or "low rear" CG position (i.e., the CG is disposed towards the sole and rear of the club head). Such a lower rear CG position provides improved launch characteristics and a more high-performance club head. Including the crown tuning elements 130 minimizes the effect on the position of the center of gravity 1000 compared to similar club heads without the tuning element 130. Described below are the desirable center of gravity 1000 positions that result in a low rear CG position.

[0104] The club head 100 having the tuning element 130 can include a CGx-axis 1050 position, a CGy-axis 1060 position, and a CGz-axis 1070 position (hereinafter, "CG position"), and these are displaced as compared with a similar club head without the crown tuning element 130. For example, in many embodiments, the CG position of the club head 100 having the crown tuning element 130 can be between 0.5% and 5% of the CG position of a similar club head without the crown tuning element 130. In other embodiments, the CG position of the club head 100 having the crown tuning element 130 can be between 0.5% and 2.5%, or between 2.5% and 5% of the CG position of a similar club head without the crown tuning element 130. For example, the CG position of the club head 100 having the crown tuning element 130 can be 0.5%, 1%, 2%, 3%, 4%, or 5% of the CG position of a similar club head without the crown tuning element 130.

[0105] For a driver, CG1000 has a CGx-axis 1050 position located in the range between -2 mm and 6 mm. In other embodiments, CG1000 has a CGx-axis 1050 position located in the range between -2 mm and 2 mm, or between 2 mm and 6 mm. For example, CG1000 has a CGx-axis 1050 position located at -2, -1.5, -1, 0, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, or 6 mm.

[0106] For a fairway wood, CG1000 has a CGx-axis 1050 position located in the range between -7 mm and 1 mm. In other embodiments, CG1000 has a CGx-axis 1050 position located in the range between -7 mm and -3 mm, or between -3 mm and 1 mm. For example, CG1000 has a CGx-axis 1050 position located at -7, -6, -5, -4, -3, -2, -1, 0, 0.5, or 1 mm.

[0107] Regarding the hybrid, CG1000 has a CGx-axis 1050 position located in the range between -5 mm and 2 mm. In other embodiments, CG1000 has a CGx-axis 1050 position located in the range between -5 mm to -1 mm, or between -1 mm and 2 mm. In other embodiments, also, CG1000 has a CGx-axis 1050 position located in the range between -4 mm and 0 mm, -3 mm and 1 mm, or -2 mm and 2 mm. For example, CG1000 has a CGx-axis 1050 position located at -5, -4, -3, -2.5, -2, -1.5, -1, -0.5, 0, 0.5, 1, 1.5, or 2 mm.

[0108] Regarding the driver, CG1000 has a CGy-axis 1060 position located in the range between -4 mm and -10 mm. In other embodiments, CG1000 has a CGy-axis 1060 position located in the range between -4 and -7 mm, or between -7 mm and -10 mm. For example, CG1000 has a CGy-axis 1060 position located at -4, -5, -6, -7, -8, -9, or -10 mm.

[0109] Regarding the fairway wood, CG1000 has a CGy-axis 1060 position located in the range between -3 mm and -12 mm. In other embodiments, CG1000 has a CGy-axis 1060 position located in the range between -3 mm and -7 mm, or between -7 mm and -12 mm. For example, CG1000 has a CGy-axis 1060 position located at -3, -4, -5, -6, -7, -8, -9, -10, -11, or -12 mm.

[0110] Regarding the hybrid, CG1000 has a CGy-axis 1060 position located in the range between -3 mm and -12 mm. In other embodiments, CG1000 has a CGy-axis 1060 position located in the range between -3 mm and -8 mm, or between -8 mm and -12 mm. In other embodiments, also, CG1000 has a CGy-axis 1060 position located in the range between -4 mm and -8 mm, -5 mm and -9 mm, -6 mm and -10 mm, -7 mm and -11 mm, or between -8 mm and -12 mm. For example, CG1000 has a CGy-axis 1060 position located at -3, -4, -5, -6, -7, -8, -9, -10, -11, or -12 mm.

[0111] Regarding the driver, CG1000 has a CGz-axis 1070 position located at a position exceeding 38 mm, exceeding 40 mm, exceeding 42 mm, exceeding 45 mm, or exceeding 48 mm. In other embodiments, CG1000 has a CGz-axis 1070 position located in the range between 38 mm and 55 mm. In other embodiments, CG1000 has a CGz-axis 1070 position located in the range between 38 and 45 mm, or between 45 and 55 mm. For example, CG1000 has a CGz-axis 1070 position located at 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, or 55 mm.

[0112] Regarding the fairway wood, CG1000 has a CGz-axis 1070 position located at a position exceeding 25 mm, exceeding 28 mm, or exceeding 30 mm. In other embodiments, CG1000 has a CGz-axis 1070 position located in the range between 25 mm and 40 mm. In other embodiments, CG1000 has a CGz-axis 1070 position located in the range between 25 mm and 32 mm, or between 32 mm and 40 mm. For example, CG1000 has a CGz-axis 1070 position located at 25, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, or 40 mm.

[0113] For the hybrid, CG1000 has a position of the CGz axis 1070 that is beyond 15 mm, beyond 18 mm, beyond 20 mm, beyond 22 mm, or beyond 24 mm. In other embodiments, CG1000 has a position of the CGz axis 1070 that is in the range between 15 mm and 30 mm. In other embodiments, CG1000 has a position of the CGz axis 1070 that is in the range between 15 mm and 25 mm, or between 25 mm and 30 mm. Also, in other embodiments, CG1000 has a position of the CGz axis 1070 that is in the range between 16 mm and 26 mm, 17 mm and 27 mm, 18 mm and 28 mm, 19 mm and 29 mm, or 20 mm and 30 mm. In other embodiments, CG1000 has a position of the CGz axis 1070 that is at 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, or 30 mm.

[0114] As described above, referring to FIGS. 2 and 3, the center of gravity (CG) 1000 defines the origin of a coordinate system having a CGx axis 2050, a CGy axis 2060, and a CGz axis 2070. The CGx axis 2050 is parallel to the x axis 1050, the CGy axis 2060 is parallel to the y axis 1060, and the CGz axis 2070 is parallel to the z axis 1070. Further, the club head 100 includes a moment of inertia Ixx about the CGx axis 1050 (i.e., the crown - sole moment of inertia), and a moment of inertia Iyy about the CGy axis 1060 (i.e., the heel - sole moment of inertia).

[0115] The moment of inertia of the club head 100 is desirably increased or maximized because a larger MOI increases the tolerance for impact deviation from the center 116 of the striking face 102 in the club head. The MOI is a characteristic of the peripheral mass distribution of the club head 100. Generally, the discretionary mass of the club head 100 is preferably allocated throughout the club head 100 so as to maximize the moment of inertia (Ixx) about the CGx axis 2050 and the moment of inertia (Iyy) about the CGy axis 2060. The crown tuning element 130 minimizes the impact on the moment of inertia as compared to a similar club head without the tuning element 130. Desirable values of the moment of inertia that provide a high tolerance are described below.

[0116] The club head 100 including the tuning element 130 can include different moments of inertia Ixx and moment of inertia Iyy (hereinafter, "moment of inertia") when compared to a similar club head without the crown tuning element 130. For example, in many embodiments, the moment of inertia of the club head 100 having the crown tuning element 130 can be between 0.5% and 5% of the moment of inertia of a similar club head without the crown tuning element 130. In other embodiments, the moment of inertia of the club head 100 having the crown tuning element 130 can be between 0.5% and 2.5%, or between 2.5% and 5% of the moment of inertia of a similar club head without the crown tuning element 130. For example, the moment of inertia of the club head 100 including the tuning element 130 can be 0.5%, 1%, 2%, 3%, 4% or 5% of the moment of inertia of a similar club head without the crown tuning element 130.

[0117] For a driver, in many embodiments, the crown-soles moment of inertia Ixx is greater than about 3000 g-cm 2 and greater than about 3250 g-cm 2 and greater than about 3500 g-cm 2 and greater than about 3750 g-cm 2Exceeding about 4000 g-cm 2 Exceeding about 4250 g-cm 2 Exceeding about 4500 g-cm 2 Exceeding about 4750 g-cm 2 or exceeding about 5000 g-cm 2 can be exceeded.

[0118] For the driver, in other embodiments, the crown-to-soled moment of inertia Ixx can range between 3000 and 5000 g-cm 2 In other embodiments, the crown-to-soled moment of inertia Ixx can range between 3000 and 4000 g-cm 2 or between 4000 and 5000 g-cm 2 For example, the crown-to-soled moment of inertia Ixx can be 3000, 3100, 3200, 3300, 3400, 3500, 3600, 3700, 3800, 3900, 4000, 4100, 4200, 4300, 4400, 4500, 4600, 4700, 4800, 4900, or 5000 g-cm 2 can be.

[0119] For the fairway wood, in many embodiments, the crown-to-soled moment of inertia Ixx exceeds about 1200 g-cm 2 exceeding about 1300 g-cm 2 exceeding about 1400 g-cm 2 exceeding about 1500 g-cm 2 exceeding about 1600 g-cm 2 exceeding about 1700 g-cm 2 exceeding about 1800 g-cm 2 exceeding or about 1900 g-cm 2 can be exceeded.

[0120] For the fairway wood, in other embodiments, the crown-to-soled moment of inertia Ixx can range between 1200 and 2200 g-cm 2 In other embodiments, the crown-to-soled moment of inertia Ixx can range between 1200 and 1700 g-cm 2、 or, in the range between 1700 and 2200 g-cm 2 can take. For example, the crown-sole moment of inertia Ixx can be 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 20040, 2100, or 2200 g-cm 2 can be.

[0121] For hybrids, in many embodiments, the crown-sole moment of inertia Ixx is greater than about 880 g-cm 2 and greater than about 890 g-cm 2 and greater than about 900 g-cm 2 and greater than about 910 g-cm 2 and greater than about 920 g-cm 2 and greater than about 930 g-cm 2 and greater than about 940 g-cm 2 and greater than about 950 g-cm 2 and greater than, or greater than about 960 g-cm 2 can be.

[0122] For hybrids, in other embodiments, the crown-sole moment of inertia Ixx can be in the range between 880 and 1500 g-cm 2 can take. In other embodiments, the crown-sole moment of inertia Ixx can be in the range between 880 and 1200 g-cm 2 or between 1200 and 1500 g-cm 2 can take. In other embodiments, also, the crown-sole moment of inertia Ixx can be in the range between 900 and 1300 g-cm 2 between 1000 and 1400 g-cm 2 or between 1100 and 1500 g-cm 2 can take. For example, the crown-sole moment of inertia Ixx can be 880, 900, 920, 930, 940, 950, 960, 970, 980, 990, 1000, 1020, 1100, 1200, 1300, 1400, or 1500 g-cm 2 can be.

[0123] For the driver, in many embodiments, the heel-toe moment of inertia Iyy exceeds about 4500 g-cm 2 exceeds about 4800 g-cm 2 exceeds about 5000 g-cm 2 exceeds about 5100 g-cm 2 exceeds about 5250 g-cm 2 exceeds about 5500 g-cm 2 exceeds about 5750 g-cm 2 exceeds, or can exceed about 6000 g-cm 2 can exceed.

[0124] For the driver, in many embodiments, the heel-toe moment of inertia Iyy can range between 4500 and 6000 g-cm 2 In other embodiments, the heel-toe moment of inertia Iyy can range between 4500 and 5200 g-cm 2 or between 5200 and 6000 g-cm 2 For example, the heel-toe moment of inertia Iyy can be 4500, 4600, 4700, 4800, 4900, 5000, 5100, 5200, 5300, 5400, 5500, 5600, 5700, 5800, 5900, or 6000 g-cm 2 can be.

[0125] For the fairway wood, the heel-toe moment of inertia Iyy exceeds about 2700 g-cm 2 exceeds about 2800 g-cm 2 exceeds about 2900 g-cm 2 exceeds about 3000 g-cm 2 exceeds about 3100 g-cm 2 exceeds about 3200 g-cm 2 exceeds, or can exceed about 3300 g-cm 2 can exceed.

[0126] For the fairway wood, the heel-toe moment of inertia Iyy is between 2700 and 3500 g-cm 2can take a range between. In other embodiments, the heel-toe moment of inertia Iyy is 2700 - 3100 g-cm 2 , or can take a range between 3100 - 3500 g-cm 2 . In other embodiments, also, the heel-toe moment of inertia Iyy is 2700 - 3200 g-cm 2 , or can take a range between 3200 - 3500 g-cm 2 . For example, the heel-toe moment of inertia Iyy can be 2700, 2800, 2900, 3000, 3100, 3200, 3300, 3400, or 3500 g-cm 2 .

[0127] For hybrids, in many embodiments, the heel-toe moment of inertia Iyy is greater than about 2400 g-cm 2 , greater than about 2500 g-cm 2 , greater than about 2600 g-cm 2 , greater than about 2700 g-cm 2 , greater than about 2800 g-cm 2 , greater than about 2900 g-cm 2 , or greater than about 3000 g-cm 2 .

[0128] For hybrids, in other embodiments, the heel-toe moment of inertia Iyy can take a range between 2400 to 3200 g-cm 2 . In other embodiments, the heel-toe moment of inertia Iyy is 2400 - 2700 g-cm 2 , or can take a range between 2700 - 3200 g-cm 2 . In other embodiments, also, the heel-toe moment of inertia Iyy is 2400 - 2900, 2500 - 3000, 2600 - 3100, or 2700 - 3200 g-cm 2 . For example, the heel-toe moment of inertia Iyy is 2400, 2500, 2600, 2700, 2750, 2800, 2850, 2900, 2950, 3000, 3100, or 3200 g-cm 2It can be.

[0129] For the driver, the combined moment of inertia (i.e., the sum of the crown - sole moment of inertia and the heel - toe moment of inertia Iyy) is over 8000 g - cm 2 over 8500 g - cm 2 over 9000 g - cm 2 over 9500 g - cm 2 over 10000 g - cm 2 over 11000 g - cm 2 over 12000 g - cm 2 or can exceed 12000 g - cm.

[0130] For the fairway wood, the combined moment of inertia (i.e., the sum of the crown - sole moment of inertia and the heel - toe moment of inertia Iyy) is over 4000 g - cm 2 over 4100 g - cm 2 over 4200 g - cm 2 over 4300 g - cm 2 over 4400 g - cm 2 over 4500 g - cm 2 over 4600 g - cm 2 over 4700 g - cm 2 over 4800 g - cm 2 or can exceed 4800 g - cm.

[0131] For the hybrid, the combined moment of inertia (i.e., the sum of the crown - sole moment of inertia and the heel - toe moment of inertia Iyy) is over 3500 g - cm 2 over 3600 g - cm 2 over 3700 g - cm 2 over 3800 g - cm 2 over 3900 g - cm 2 over 4000 g - cm 2 over 4100 g - cm 2 over 4200 g - cm 2 or can exceed 4200 g - cm.

[0132] Example Example 1 In one example, the amplitude of the natural frequency of a control multi-material fairway wood type club head without tuning elements at impact was measured and compared to a plurality of exemplary multi-material fairway wood type club heads each having a tuning element on the inner surface of the crown. The control club head included a hot spot at a natural frequency of 5860 Hz located near the heel of the crown within the rear-heel quadrant 176. The first exemplary multi-material club head included a 1 gram tuning element disposed within the hot spot (i.e., the rear-heel quadrant) of the control club. Similarly, the second exemplary multi-material club head included a 2 gram tuning element disposed within the hot spot of the control club. The amplitude of the natural frequency of 5860 Hz was compared among the control club head, the first exemplary club head, and the second exemplary club head. [Table 2]

[0133] As shown in Table 2, the first exemplary club head and the second exemplary club head each had a reduction in amplitude relative to the natural frequency of the control club. The first exemplary club head had a 2 decibel reduction in amplitude while the second exemplary club head had a 6 decibel reduction in amplitude. In other words, the first exemplary club head had a 20.5% reduction in vibrational energy at a natural frequency of 5860 Hz and the second exemplary club head had a 50% reduction in vibrational energy at a natural frequency of 5860 Hz. The dramatic reduction in vibrational energy from the control club head to the first exemplary club head and the second exemplary club indicates that each of the first exemplary club head and the second exemplary club includes a softer and weaker acoustic response than the acoustic response of the control club.

[0134] Furthermore, a test was conducted to compare the duration of the vibration response of a first exemplary club head and a second exemplary club head with respect to the control club head. The total duration, the duration of the sustain phase, and the duration of the release phase of the vibration response of each club head were measured and compared. As described above, the total duration refers to the amount of time from the impact between the club head and the ball until the club head stops vibrating. The duration of the sustain phase refers to the amount of time during which the vibration response is within 20% of the peak vibration amplitude. The duration of the release phase refers to the amount of time from the end of the sustain duration (i.e., when the vibration drops below 20% of the peak amplitude) to the end of the total vibration response. Generally, a vibration response with a greater duration is perceived as a more annoying sound than a vibration response with a shorter duration. A longer sustain phase contributes to a response with a more annoying sound for a longer time, while a longer release phase contributes to a prolonged "ringing" sensation. Table 3 below shows the sustain duration, release duration, and total duration (the sum of the sustain duration and release duration) of the time response of the vibration for each club head.

Table 3

[0135] As shown in Table 3, the club head with a 1-gram tuning element received a total vibration response that was slightly shorter (0.29 milliseconds shorter) than the control club, while the club head with a 2-gram tuning element received a total vibration response that was 6.74 milliseconds shorter (18.2% shorter) than the control club.

[0136] Referring to the sustain phase, which is the most significant contributor to the overall perception of the sound for each club head, both exemplary club heads showed significant improvement over the control club. The sustain phase of the club head with a 1-gram tuning element was 1.73 milliseconds shorter (18.1% shorter) than the sustain phase of the control club head, and the sustain phase of the club head with a 2-gram tuning element was 6.62 milliseconds shorter (69.1% shorter) than the sustain phase of the control club head.

[0137] Including the tuning element not only reduces the dominant vibration amplitude of the club head, but also significantly shortens the duration of the dominant vibration. The combination of reduced vibration and a shorter dominant vibration duration results in a club head having a softer and more comfortable acoustic response at impact.

[0138] Example 2 In a second example, the amplitude of the natural frequency of a control multi-material fairway wood type club head without a tuning element at impact was measured and compared to a third exemplary multi-material fairway wood type club head having a tuning element on the inner surface of the crown. The control club head included a hot spot at a natural frequency of 6147 Hz located near the toe of the crown within the rear-toe quadrant. The third exemplary multi-material club head included a 2 gram tuning element placed within the hot spot (i.e., the rear-toe quadrant) of the control club. The amplitude of the natural frequency of 6147 Hz was compared between the control club head and the third exemplary club head.

[0139] The amplitude of 6147 Hz at the hot spot of the control club was 67 decibels while the amplitude of the natural frequency of 6147 Hz of the third exemplary club head was only 62.5 decibels. The 4.5 decibel decrease between the control club and the third exemplary club head is equivalent to a 40.5% reduction in the vibration energy at the dominant natural frequency of 6147 Hz. The dramatic reduction in vibration energy from the control club head to the third exemplary club head indicates that the third exemplary club head includes a softer, weaker, and more comfortable acoustic response than the control club head.

[0140] Furthermore, a test was conducted to compare the duration of the vibration response of a third exemplary club head with respect to a control club head. The total duration, the "sustained" phase duration, and the "release" phase duration of the vibration response of each club head were measured and compared. Table 4 below shows the sustained duration, the release duration, and the total duration (the sum of the sustained duration and the release duration) of the time response of each club head vibration. [Table 4]

[0141] As shown in Table 4, the third exemplary club head with a 2-gram tuning element in the rear - toe quadrant received a total vibration response that was 10.04 milliseconds shorter (27% shorter) than the control club. Referring to the sustained phase, which is the most significant contributor to the overall perception of sound in the club head, the third exemplary club head showed a significant improvement over the control club. The sustained phase of the club head with a 2-gram tuning element was 6.96 milliseconds shorter than the sustained phase of the control club head.

[0142] Including the tuning element not only reduced the peak vibration amplitude of the club head but also significantly shortened the duration of the peak vibration. The combination of reduced vibration and a shorter peak vibration duration results in a club head with a softer and more pleasant acoustic response at impact.

[0143] Example 3 The mass characteristics were compared between a control fairway wood - type club head and the first exemplary fairway wood - type golf club head of Example 1 and the second exemplary fairway wood - type golf club head. Specifically, the center - of - gravity (CG) position and the moment of inertia (MOI) of each club were compared to determine the influence of including the tuning element. Table 5 below shows the center - of - gravity position in the Y - direction CGy, measured positive with respect to the ground plane, the center - of - gravity position in the Z - direction, measured negative from the leading edge, the moment of inertia about the CGx axis (Ixx), and the moment of inertia about the CGy axis (Iyy).

Table 5

[0144] Including 1 gram of tuning element resulted in a CG position rise of only 0.12 mm higher than the control club in the Y direction (a slight 2.7% increase relative to the control club CG height). Similarly, including 2 grams of tuning element resulted in a CG position 0.25 mm higher than the control club (a slight 5.7% increase in CG height).

[0145] Including 1 gram of tuning element resulted in a CG position 0.13 mm forward of the control club in the Z direction (a slight 0.44% decrease relative to the control club CG depth). Similarly, including 2 grams of tuning element resulted in a CG position slightly 0.25 mm forward of the control club (a slight 0.85% decrease in CG depth). Even when including the tuning element, the exemplary club head still maintains a low rearward CG position.

[0146] Regarding the moment of inertia of the club head about the CG x-axis, including 1 gram of tuning element resulted in a slight reduction of 14 g*cm 2 in Ixx (a slight 0.89% decrease in Ixx relative to the control club head). Similarly, including 2 grams of tuning element resulted in a reduction of slightly 30 g*cm 2 in Ixx (a slight 1.9% decrease in Ixx).

[0147] Regarding the moment of inertia of the club head about the CG y-axis, including 1 gram of tuning element resulted in a slight reduction of 16 g*cm 2 in Iyy (a slight 0.54% decrease in Iyy relative to the control club head). Similarly, including 2 grams of tuning element resulted in a reduction of slightly 35 g*cm 2resulted in a reduction of Iyy (a decrease of only 1.18% in Iyy). Even when tuning elements are included, the exemplary club head still maintains a high moment of inertia.

[0148] As described above in Example 1, including 1 gram and 2 gram tuning elements results in a dramatic improvement in the vibration response of the club head. Examples of the present invention show that such an improvement in vibration can be achieved by lightweight tuning elements that have little impact on the mass characteristics of the club head. Thus, the vibration response of the club head can be controlled and improved without sacrificing the mass characteristics that provide high performance.

[0149] The substitution of one or more claim elements constitutes a rearrangement and not a patch. Further, advantages over the problem, other advantages and solutions have been described in connection with specific embodiments. However, an advantage over the problem, other advantages and solutions, and any one or more elements that cause or make apparent any advantage, advantage or solution, do not constitute a material, essential or essential feature or element of any or all of the claim elements unless such advantage, advantage, solution or element is explicitly stated in such claims.

[0150] The rules for golf are sometimes changed (e.g., new rules may be applied by golf standard organizations and / or regulatory bodies such as the United States Golf Association (USGA), the Royal & Ancient Golf Club of St Andrews (R&A), etc., or old rules may be repealed or changed), so golf equipment related to the devices, methods and products described herein may or may not conform to the rules of golf at any given time. Accordingly, golf equipment related to the devices, methods and products described herein may be marketed, sold and / or sold as conforming or non-conforming golf equipment. The devices, methods and products described herein are not limited in this regard.

[0151] Furthermore, the embodiments and limitations described herein are not provided to the public under the doctrine of disclosure if the embodiments and / or limitations are (1) not expressly claimed in the claims and (2) equivalent or potentially equivalent to the recited elements and / or limitations in the claims under the doctrine of equivalents.

[0152] (Clause 1) A golf club head, comprising a crown, a sole on the opposite side of the crown, a heel end, a toe end on the opposite side of the heel end, a front end portion having a leading edge, a rear end portion, and a skirt extending between the crown and the sole, a first component formed of metal, the first component comprising a striking face, a return portion extending rearward from the striking face, and a sole rear extension extending rearward from the return portion, and a second component formed of a non-metallic material, the second component being configured to be fixed to the first component so as to surround a hollow internal cavity, the second component forming most of the crown, wrapping around the periphery of the skirt, and forming at least a part of the heel end, the toe end, and the sole, the striking face having a striking face center, the striking face center defining a starting point of a coordinate system including an x-axis that horizontally extends through the striking face center in a direction extending from the heel end to the toe end when the club head is in an address position, a y-axis that perpendicularly extends through the striking face center in a direction extending from the crown to the sole and is orthogonal to the x-axis, and a z-axis that horizontally extends through the striking face center in a direction extending from the striking face to the rear end portion and is orthogonal to both the x-axis and the y-axis, the second component, a front end reference plane in contact with the leading edge and orthogonal to a ground plane, the ground plane being defined as contacting the sole at the address position, the front end reference plane, a rear end reference plane in contact with the rear end portion and parallel to the front end reference plane, a central plane orthogonal to the ground plane and positioned midway between the front end reference plane and the rear end reference plane, and a YZ plane extending along the y-axis and the z-axis orthogonal to the ground plane, the intersection of the central plane and the YZ plane dividing the club head into a quadrant system having a front-toe quadrant, a front-heel quadrant, a rear-toe quadrant, and a rear-heel quadrant when the club head is viewed from above, the YZ plane,A tuning element fixed to the inner surface of the second component within the rear - heel quadrant, and the tuning element includes an adhesive layer, a reinforcing layer on the opposite side of the adhesive layer, and a damping layer sandwiched between the adhesive layer and the reinforcing layer. The reinforcing layer includes a glass cloth, the damping layer includes a thermoplastic elastomer. The club head includes a hot spot within the rear - heel quadrant, and the hot spot is defined as the maximum amplitude position of the natural frequency when the club head does not have the tuning element. The natural frequency of the club head is between 5000 Hz and 6500 Hz. The tuning element is disposed on the hot spot and is configured to suppress the maximum amplitude of the natural frequency. When the club head including the tuning element vibrates at the natural frequency, the maximum amplitude is reduced by at least 2 decibels compared to a similar club head without the tuning element. A golf club head.

[0153] (Clause 2) The tuning element further includes a tuning element center point located at the middle between the most heel - side portion and the most toe - side portion of the tuning element, and at the middle between the most front - side portion and the most rear - side portion of the tuning element. The tuning element center point is located within the rear - heel quadrant. The golf club head according to Clause 1.

[0154] (Clause 3) The offset distance, which is parallel to the z - axis and measured between the front - end reference plane and the tuning element center point, is between 1.5 inches and 2.0 inches. The golf club head according to Claim 2.

[0155] (Clause 4) The second component further includes a second - component crown portion forming at least a part of the crown of the club head. The golf club head according to Clause 1.

[0156] (Clause 5) The golf club head according to claim 1, further comprising a position feature portion that defines a concave portion on the outer surface of the crown, wherein the position feature portion includes an edge portion that separates the concave portion from a non-concave portion of the crown adjacent to the concave portion.

[0157] (Clause 6) The golf club head according to claim 5, further comprising an alignment feature portion, wherein the alignment feature portion protrudes from the inner surface of the second component located on the opposite side of the concave portion of the crown, and the tuning element is fixed to the alignment feature portion.

[0158] (Clause 7) The golf club head according to claim 1, wherein the natural frequency of the club head is between 5500 Hz and 6000 Hz.

[0159] (Clause 8) The golf club head according to claim 1, wherein the tuning element is connected to the inner surface of the second component by an adhesive.

[0160] (Clause 9) The golf club head according to claim 1, wherein the tuning element has a mass between 0.5 grams and 4 grams.

[0161] (Clause 10) The volume of the club head is less than 200 cc. The club head has a center of gravity that defines the origin of a coordinate system including a CGx axis parallel to the ground plane in a direction extending from the heel end to the toe end when the club head is in the address position, and a CGy axis perpendicular to the ground plane in a direction extending from the sole to the crown. The club head includes an Ixx moment of inertia about the CGx axis exceeding 1500 g*cm 2 and an Iyy moment of inertia about the CGy axis exceeding 2900 g*cm 2 The golf club head according to claim 1.

[0162] (Clause 11) A golf club head, comprising a crown, a sole on the opposite side of the crown, a heel end, a toe end on the opposite side of the heel end, a front end portion including a leading edge, a rear end portion, and a skirt extending between the crown and the sole, a first component formed of metal, the first component including a striking face, a return portion extending rearward from the striking face, and a sole rear extension portion extending rearward from the return portion, and a second component formed of a non-metallic material, the second component being configured to be fixed to the first component so as to surround a hollow internal cavity, forming most of the crown, wrapping around the skirt, and forming at least a part of the heel end, the toe end, and the sole, the striking face having a striking face center, the striking face center defining a starting point of a coordinate system including an x-axis that horizontally extends through the striking face center in a direction extending from the heel end to the toe end when the club head is in the address position, a y-axis that vertically extends through the striking face center in a direction extending from the crown to the sole and is orthogonal to the x-axis, and a z-axis that horizontally extends through the striking face center in a direction extending from the striking face to the rear end portion and is orthogonal to both the x-axis and the y-axis, the second component, a front end reference plane in contact with the leading edge and orthogonal to a ground plane, the ground plane being defined as being in contact with the sole at the address position, the front end reference plane, a rear end reference plane in contact with the rear end portion and parallel to the front end reference plane, a central plane orthogonal to the ground plane and located in the middle between the front end reference plane and the rear end reference plane, and a YZ plane extending along the y-axis and the z-axis orthogonal to the ground plane, when viewing the club head from above, an intersection line of the central plane and the YZ plane divides the club head into a quadrant system having a front-toe quadrant, a front-heel quadrant, a rear-toe quadrant, and a rear-heel quadrant, the YZ plane,A tuning element fixed to the inner surface of the second component within the rear-toe quadrant, wherein the tuning element comprises an adhesive layer, a reinforcing layer on the opposite side of the adhesive layer, and a damping layer sandwiched between the adhesive layer and the reinforcing layer, the reinforcing layer includes a glass cloth, the damping layer includes a thermoplastic elastomer, the club head includes a hot spot within the rear-heel quadrant, the hot spot is defined as the maximum amplitude position of the natural frequency when the club head does not have the tuning element, the natural frequency of the club head is between 5000 Hz and 6500 Hz, the tuning element is disposed on the hot spot, the tuning element is configured to suppress the maximum amplitude of the natural frequency, and when the club head including the tuning element vibrates at the natural frequency, the maximum amplitude is reduced by at least 2 decibels compared to a similar club head without the tuning element. Golf club head.

[0163] (Clause 12) The natural frequency of the club head is between 6000 Hz and 6500 Hz. The golf club head according to claim 11.

[0164] (Clause 13) The tuning element further comprises a tuning element center point located at an intermediate position between the most heelward portion and the most toeward portion of the tuning element, and at an intermediate position between the most forward portion and the most rearward portion of the tuning element. The tuning element center point is located within the rear-toe quadrant. The golf club head according to claim 11.

[0165] (Clause 14) The volume of the club head is less than 200 cc. The club head has a center of gravity that defines the origin of a coordinate system including a CGx axis parallel to the ground plane in a direction extending from the heel end to the toe end when the club head is in the address position, and a CGy axis perpendicular to the ground plane in a direction extending from the sole to the crown. The club head is 1500 g*cm 2including the moment of inertia Ixx about the CGx axis exceeding, the club head being 2900 g*cm 2 The golf club head according to claim 11, including the moment of inertia Iyy about the CGy axis exceeding

[0166] (Clause 15) A golf club head, comprising a crown, a sole on the opposite side of the crown, a heel end, a toe end on the opposite side of the heel end, a front end portion having a leading edge, a rear end portion, and a skirt extending between the crown and the sole; a first component formed of metal, the first component having a striking face, a return portion extending rearward from the striking face, and a sole rear extension portion extending rearward from the return portion; a second component formed of a non-metallic material, the second component being configured to be fixed to the first component so as to surround a hollow internal cavity, the second component forming most of the crown, wrapping around the periphery of the skirt, and forming at least a part of the heel end, the toe end, and the sole, wherein the striking face has a striking face center, the striking face center defining a starting point of a coordinate system including an x-axis that horizontally extends through the striking face center in a direction extending from the heel end to the toe end when the club head is in the address position, a y-axis that vertically extends through the striking face center in a direction extending from the crown to the sole and is orthogonal to the x-axis, and a z-axis that horizontally extends through the striking face center in a direction extending from the striking face to the rear end portion and is orthogonal to both the x-axis and the y-axis; a front end reference plane that is in contact with the leading edge and orthogonal to the ground plane, the ground plane being defined as being in contact with the sole at the address position; a rear end reference plane that is in contact with the rear end portion and parallel to the front end reference plane; a central plane that is orthogonal to the ground plane and is located in the middle between the front end reference plane and the rear end reference plane; and a YZ plane that extends along the y-axis and the z-axis that are orthogonal to the ground plane, wherein when the club head is viewed from above, an intersection line of the central plane and the YZ plane divides the club head into a quadrant system having a front-toe quadrant, a front-heel quadrant, a rear-toe quadrant, and a rear-heel quadrant.A tuning element fixed to the inner surface of the second component within the rear - heel quadrant, and the tuning element includes an adhesive layer, a reinforcing layer on the opposite side of the adhesive layer, and a damping layer sandwiched between the adhesive layer and the reinforcing layer. The reinforcing layer includes a glass cloth, the damping layer includes a thermoplastic elastomer. The club head includes a hot spot within the rear - heel quadrant, and the hot spot is defined as the maximum amplitude position of the natural frequency when the club head does not have the tuning element. The natural frequency of the club head is between 5000 Hz and 6500 Hz. The tuning element is disposed on the hot spot, and the tuning element is configured to suppress the maximum amplitude of the natural frequency. When the club head including the tuning element vibrates at the natural frequency, the maximum amplitude is reduced by at least 2 decibels compared to a similar club head without the tuning element, and the maximum amplitude of the natural frequency is 65 decibels or less. A golf club head.

[0167] (Clause 16) The natural frequency of the club head is between 5500 Hz and 6000 Hz. The golf club head according to claim 15.

[0168] (Clause 17) The tuning element further includes a tuning element center point located at an intermediate position between the most heel - side portion and the most toe - side portion of the tuning element, and at an intermediate position between the most forward portion and the most rearward portion of the tuning element. The tuning element center point is located within the rear - heel quadrant. The golf club head according to claim 15.

[0169] (Clause 18) The tuning element has a density between 0.5 g / cm 3 ~1.5 g / cm 3 The golf club head according to claim 15.

[0170] (Clause 19) The golf club head according to claim 15, wherein the reinforcing layer has a tensile strength exceeding 60 MPa.

[0171] (Clause 20) The golf club head according to claim 16, wherein the natural frequency of the golf club head is approximately 5860 Hz.

[0172] Various features and advantages of the present disclosure are set forth in the following claims.

Claims

1. A golf club head, a crown, a sole opposite the crown, a heel end, a toe end opposite the heel end, a front end having a leading edge, a rear end, and a skirt extending between the crown and the sole; a first component formed from a metal, the first component including a strike face, a return portion extending rearwardly from the strike face, and a sole rear extension extending rearwardly from the return portion; a second component formed from a non-metallic material, the second component configured to be secured to the first component to enclose a hollow interior cavity, the second component forming a majority of the crown and wrapping around the skirt to form the heel end, the toe end, and at least a portion of the sole; the strike face comprises a strike face center; the strike face center defines the origin of a coordinate system that includes an x-axis extending horizontally through the strike face center in a direction extending from the heel end to the toe end when the club head is in an address position, a y-axis extending vertically through the strike face center in a direction extending from the crown to the sole and orthogonal to the x-axis, and a z-axis extending horizontally through the strike face center in a direction extending from the strike face to the tail end and orthogonal to both the x-axis and the y-axis. the second component; and a front end reference plane tangent to the leading edge and perpendicular to a ground plane, the ground plane being defined as tangent to the sole at the address position; a rear end reference plane tangent to the rear end and parallel to the front end reference plane; a mid-plane perpendicular to the ground plane and midway between the front end reference plane and the rear end reference plane; a YZ plane extending along the y-axis and the z-axis perpendicular to the ground plane, When the club head is viewed from above, the intersection of the midplane and the YZ plane divides the club head into a quadrant system having a front-toe quadrant, a front-heel quadrant, a rear-toe quadrant, and a rear-heel quadrant. The YZ plane; a tuning element secured to an inner surface of the second component in the rear-heel quadrant; Equipped with the tuning element comprises an adhesive layer, a stiffening layer opposite the adhesive layer, and a vibration damping layer sandwiched between the adhesive layer and the stiffening layer; The reinforcing layer includes a glass cloth, The vibration-damping layer includes a thermoplastic elastomer, the club head includes a hot spot in the rear-heel quadrant, the hot spot being defined as a location of maximum amplitude of a natural frequency when the club head does not have the tuning element; the natural frequency of the club head is between 5000 Hz and 6500 Hz; the tuning element is disposed over the hot spot, the tuning element being configured to suppress the maximum amplitude of the natural frequency; when the club head including the tuning element vibrates at the natural frequency, the maximum amplitude is reduced by at least 2 decibels as compared to a similar club head without the tuning element. Golf club head.

2. the tuning element further comprising a tuning element center point located midway between a heel-most portion of the tuning element and a toe-most portion of the tuning element and midway between a forward-most portion of the tuning element and a rearward-most portion of the tuning element; The golf club head of claim 1 , wherein the tuning element center point is located within the rear-heel quadrant.

3. 3. The golf club head of claim 2, wherein an offset distance parallel to the z-axis and measured between the front end reference plane and the tuning element center point is between 1.5 inches and 2.0 inches.

4. The second component further comprises: a second component crown portion forming at least a portion of the crown of the club head; a second component heel portion that wraps around at least a portion of the heel end of the club head; a second component toe portion that wraps around at least a portion of the toe end of the club head; Equipped with The golf club head of claim 1 , wherein the tuning element is secured to an inner surface of the second component crown portion.

5. a location feature defining a recessed portion on an outer surface of the crown; The golf club head of claim 1 , wherein the location feature comprises an edge separating the recessed portion from a non-recessed portion of the crown adjacent the recessed portion.

6. further comprising an alignment feature; the alignment feature projects from the inner surface of the second component opposite the recessed portion of the crown; The golf club head of claim 5 , wherein the tuning element is affixed to the alignment feature.

7. 2. The golf club head of claim 1, wherein the natural frequency of the club head is between 5500 Hz and 6000 Hz.

8. The golf club head of claim 1 , wherein the tuning element is adhesively coupled to the inner surface of the second component.

9. The golf club head of claim 1 , wherein the tuning element comprises a mass between 0.5 grams and 4 grams.

10. the volume of the club head is less than 200 cc; the club head comprises a center of gravity that defines an origin of a coordinate system including a CGx axis parallel to the ground plane in a direction extending from the heel end to the toe end and a CGy axis perpendicular to the ground plane in a direction extending from the sole to the crown when the club head is in the address position; The club head has a resistance of 1500 g*cm ２ Including an Ixx moment of inertia about the CGx axis exceeding The club head has a weight of 2900 g*cm ２ The golf club head of claim 1 , comprising an Iyy moment of inertia about the CGy axis that exceeds

11. A golf club head, a crown, a sole opposite the crown, a heel end, a toe end opposite the heel end, a front end having a leading edge, a rear end, and a skirt extending between the crown and the sole; a first component formed from a metal, the first component including a strike face, a return portion extending rearwardly from the strike face, and a sole rear extension extending rearwardly from the return portion; a second component formed from a non-metallic material, the second component configured to be secured to the first component so as to enclose a hollow interior cavity, the second component forming a majority of the crown and wrapping around the skirt to form the heel end, the toe end, and at least a portion of the sole; the strike face comprises a strike face center; the strike face center defines the origin of a coordinate system that includes an x-axis extending horizontally through the strike face center in a direction extending from the heel end to the toe end when the club head is in an address position, a y-axis extending vertically through the strike face center in a direction extending from the crown to the sole and orthogonal to the x-axis, and a z-axis extending horizontally through the strike face center in a direction extending from the strike face to the tail end and orthogonal to both the x-axis and the y-axis. the second component; and a front end reference plane tangent to the leading edge and perpendicular to a ground plane, the ground plane being defined as tangent to the sole at the address position; a rear end reference plane tangent to the rear end and parallel to the front end reference plane; a mid-plane perpendicular to the ground plane and midway between the front end reference plane and the rear end reference plane; a YZ plane extending along the y-axis and the z-axis perpendicular to the ground plane, When the club head is viewed from above, the intersection of the midplane and the YZ plane divides the club head into a quadrant system having a front-toe quadrant, a front-heel quadrant, a rear-toe quadrant, and a rear-heel quadrant. The YZ plane; a tuning element secured to an inner surface of the second component in the rear-toe quadrant; Equipped with the tuning element comprises an adhesive layer, a stiffening layer opposite the adhesive layer, and a vibration damping layer sandwiched between the adhesive layer and the stiffening layer; The reinforcing layer includes a glass cloth, The vibration-damping layer includes a thermoplastic elastomer, the club head includes a hot spot in the rear-heel quadrant, the hot spot being defined as a location of maximum amplitude of a natural frequency when the club head does not have the tuning element; the natural frequency of the club head is between 5000 Hz and 6500 Hz; the tuning element is disposed over the hot spot, the tuning element being configured to suppress the maximum amplitude of the natural frequency; when the club head including the tuning element vibrates at the natural frequency, the maximum amplitude is reduced by at least 2 decibels as compared to a similar club head without the tuning element. Golf club head.

12. The golf club head of claim 11, wherein the natural frequency of the club head is between 6000 Hz and 6500 Hz.

13. the tuning element further comprising a tuning element center point located midway between a heel-most portion of the tuning element and a toe-most portion of the tuning element and midway between a forward-most portion of the tuning element and a rearward-most portion of the tuning element; The golf club head of claim 11, wherein the tuning element center point is located within the back-to-toe quadrant.

14. the volume of the club head is less than 200 cc; the club head comprises a center of gravity that defines an origin of a coordinate system including a CGx axis parallel to the ground plane in a direction extending from the heel end to the toe end and a CGy axis perpendicular to the ground plane in a direction extending from the sole to the crown when the club head is in the address position; The club head has a resistance of 1500 g*cm ２ Including an Ixx moment of inertia about the CGx axis exceeding The club head has a weight of 2900 g*cm ２ The golf club head of claim 11 , including a Iyy moment of inertia about the CGy axis that exceeds

15. A golf club head, a crown, a sole opposite the crown, a heel end, a toe end opposite the heel end, a front end having a leading edge, a rear end, and a skirt extending between the crown and the sole; a first component formed from a metal, the first component including a strike face, a return portion extending rearwardly from the strike face, and a sole rear extension extending rearwardly from the return portion; a second component formed from a non-metallic material, the second component configured to be secured to the first component so as to enclose a hollow interior cavity, the second component forming a majority of the crown and wrapping around the skirt to form the heel end, the toe end, and at least a portion of the sole; the strike face comprises a strike face center; the strike face center defines the origin of a coordinate system that includes an x-axis extending horizontally through the strike face center in a direction extending from the heel end to the toe end when the club head is in an address position, a y-axis extending vertically through the strike face center in a direction extending from the crown to the sole and orthogonal to the x-axis, and a z-axis extending horizontally through the strike face center in a direction extending from the strike face to the tail end and orthogonal to both the x-axis and the y-axis. the second component; and a front end reference plane tangent to the leading edge and perpendicular to a ground plane, the ground plane being defined as tangent to the sole at the address position; a rear end reference plane tangent to the rear end and parallel to the front end reference plane; a mid-plane perpendicular to the ground plane and midway between the front end reference plane and the rear end reference plane; a YZ plane extending along the y-axis and the z-axis perpendicular to the ground plane, When the club head is viewed from above, the intersection of the midplane and the YZ plane divides the club head into a quadrant system having a front-toe quadrant, a front-heel quadrant, a rear-toe quadrant, and a rear-heel quadrant. The YZ plane; a tuning element secured to an inner surface of the second component in the rear-heel quadrant; Equipped with the tuning element comprises an adhesive layer, a stiffening layer opposite the adhesive layer, and a vibration damping layer sandwiched between the adhesive layer and the stiffening layer; The reinforcing layer includes a glass cloth, The vibration-damping layer includes a thermoplastic elastomer, the club head includes a hot spot in the rear-heel quadrant, the hot spot being defined as a location of maximum amplitude of a natural frequency when the club head does not have the tuning element; the natural frequency of the club head is between 5000 Hz and 6500 Hz; the tuning element is disposed over the hot spot, the tuning element being configured to suppress the maximum amplitude of the natural frequency; when the club head including the tuning element vibrates at the natural frequency, the maximum amplitude is reduced by at least 2 decibels as compared to a similar club head without the tuning element; The maximum amplitude of the natural frequency is 65 decibels or less. Golf club head.

16. The golf club head of claim 15, wherein the natural frequency of the club head is between 5500 Hz and 6000 Hz.

17. the tuning element further comprising a tuning element center point located midway between a heel-most portion of the tuning element and a toe-most portion of the tuning element and midway between a forward-most portion of the tuning element and a rearward-most portion of the tuning element; The golf club head of claim 15, wherein the tuning element center point is located within the rear-heel quadrant.

18. The tuning element has a resistance of 0.5 g / cm ３ ~1.5g / cm ３ The golf club head of claim 15 , comprising a density between 0.1 and 0.

5.

19. The golf club head of claim 15 , wherein the reinforcing layer has a tensile strength of greater than 60 MPa.

20. 17. The golf club head of claim 16, wherein the natural frequency of the golf club head is approximately 5860 Hz.

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