Golf club head

Disclosed golf club heads include a body defining an interior cavity, a face, a sole, a crown, a skirt, and a hosel. Certain embodiments include a channel positioned in a forward portion of the sole. Some embodiments include one or more of a split mass pad and/or one or more weight ports positioned behind the channel. Additionally or alternatively, one or more mass pads or weight ports may be positioned adjacent to the periphery of the sole portion. Some embodiments further include an adjustable head-shaft connection assembly configured to adjustably couple the hosel to a golf club shaft.

FIELD

The present application concerns golf club heads, and more particularly, golf club heads for fairway woods and other wood-type clubs.

INCORPORATIONS BY REFERENCE

BACKGROUND

Much of the recent improvement activity in the field of golf has involved the use of new and increasingly more sophisticated materials in concert with advanced club-head engineering. For example, modern “wood-type” golf clubs (notably, “drivers,” “fairway woods,” and “utility or hybrid clubs”), with their sophisticated shafts and non-wooden club-heads, bear little resemblance to the “wood” drivers, low-loft long-irons, and higher numbered fairway woods used years ago. These modern wood-type clubs are generally called “metalwoods” since they tend to be made primarily of strong, lightweight metals, such as titanium.

An exemplary metalwood golf club such as a driver or fairway wood typically includes a hollow shaft having a lower end to which the golf club head is attached. Most modern versions of these golf club heads are made, at least in part, of a lightweight but strong metal such as titanium alloy. In many cases, the golf club head comprises a body made primarily of such strong metals.

Some current approaches to reducing structural mass of a metalwood club-head are directed to making one or more portions of the golf club head of an alternative material. Whereas the bodies and face plates of most current metalwoods are made of titanium alloys, some golf club heads are made, at least in part, of components formed from either graphite/epoxy-composite (or other suitable composite material) and a metal alloy. Graphite composites have a much lower density compared to titanium alloys, which offers an opportunity to provide more discretionary mass in the club-head.

The ability to utilize such materials to increase the discretionary mass available for placement at various points in the club-head allows for optimization of a number of physical properties of the club-head which can greatly impact the performance obtained by the user. Forgiveness on a golf shot is generally maximized by configuring the golf club head such that the center of gravity (“CG”) of the golf club head is optimally located and the moment of inertia (“MOI”) of the golf club head is maximized. CG and MOI can also critically affect a golf club head's performance, such as launch angle and flight trajectory on impact with a golf ball, among other characteristics.

In addition to the use of various materials to optimize the strength-to-weight properties and acoustic properties of the golf club heads, advances have been made in the mass distribution properties provided by using thicker and thinner regions of materials, raising and lowering certain portions of the sole and crown, providing adjustable weight members and adjustable head-shaft connection assemblies, and many other golf club head engineering advances.

SUMMARY

This application discloses, among other innovations, fairway wood-type golf club heads that provide, among other attributes, improved forgiveness, ball speed, adjustability and playability, while maintaining durability.

The following describes wood-type golf club heads that include a body defining an interior cavity, a sole portion positioned at a bottom portion of the golf club head, a crown portion positioned at a top portion, and a skirt portion positioned around a periphery between the sole and crown. The body also has a face defining a forward portion extending between a heel portion of the golf club head and a toe portion of the golf club head, a rearward portion opposite the face, and a hosel.

Certain of the described golf club heads have a channel, a slot, or other member that increases or enhances the perimeter flexibility of the striking face of the golf club head in order to increase the coefficient of restitution and/or characteristic time of the golf club head and frees up additional discretionary mass which can be utilized elsewhere in the golf club head. In some instances, the channel, slot, or other mechanism is located in the forward portion of the sole of the golf club head, adjacent to or near to the forwardmost edge of the sole. Also, in some instances, the channel extends into the interior cavity of the golf club head, the channel extending substantially in a heel-toe direction.

Further, certain of the described golf club heads have a plurality of areas of concentrated mass, which may in some cases may be positioned to affect various performance characteristics of the club, and in some cases may be removable by the user to further tune various aspects of the golf club head's performance.

The concentrated mass in one instance may comprise a mass pad positioned on an interior of the sole rearward of and adjacent to the channel. In certain instances, this forward mass pad has a plurality of integral mass sections, such as a heel mass section, a toe mass section, and a middle mass section positioned between the heel mass section and the toe mass section. In particular instances, each of the heel and toe mass sections has a mass that is greater than the mass of the middle mass section, and a forward to rearward dimension that is greater than a forward to rearward dimension of the middle mass section. In particular instances, the toe mass section and the heel mass section each has a mass between about 10 grams and about 40 grams, and the middle mass section has a mass between about 5 grams and about 15 grams. In some instances, a weight port may be positioned behind the middle mass section for securing and at least partially retaining a removable weight. The removable weight may vary in mass, as selected by a user. In particular instances at least one removable weight having a mass between about 0.5 grams to about 30 grams, or from about 0.5 grams to about 20 grams, or from about 2 grams to about 18 grams is provided, the at least one removable weight configured to be installed at least partially within the weight port. In other cases, a void may be provided behind the middle mass section, so that mass may be distributed elsewhere within the golf club head.

In addition to the forward mass pad, in some of the described golf club heads, a second, rearward mass pad is positioned at or near the periphery of the club in the rearward portion of the club. In some cases, the rearward mass pad is positioned in the heel portion of the rearward portion of the golf club head. In some instances, the rearward mass pad has a mass between about 10 grams and about 40 grams, or between about 10 grams and about 30 grams, or between about 5 grams and about 15 grams.

Certain of the described golf club heads have either one (as described above), or a plurality of weight ports in which removable weights selectable by a user may be at least partially retained. In certain instances, a first plurality of weight ports is positioned in the sole of the golf club head rearward of and adjacent to the channel and a second plurality of weight ports in addition to the first plurality of weight ports is positioned in the sole of the golf club head adjacent the skirt portion. In particular cases, one or more of the second plurality of weight ports is positioned rearward of the channel. In particular cases, two of the second plurality of weight ports are positioned in: a) the toe portion and the rearward portion of the golf club head, b) the heel portion and the rearward portion of the golf club head, and/or c) the toe portion and the heel portion of the golf club head. In particular instances, the first plurality of weight ports comprises three weight ports. In particular instances, the second plurality of weight ports comprises at least three weight ports. Additionally, in some instances the golf club head comprises a plurality of rib sections, each extending between one of the first plurality of weight ports and a corresponding one of the second plurality of weight ports. In some instances, the golf club head further comprises an adjustable head-shaft connection assembly configured to adjustably couple the hosel to a golf club shaft.

In some instances, golf club heads disclosed herein have one or more of the following features, alone or in combination:a height less than about 46 mm;a volume of between about 125 and 250 cm3;a moment of inertia about an x axis (Ixx) greater than about 70 to 220 kg-mm2;a moment of inertia about a z axis (Izz), greater than about 170 to 375 kg-mm2;an above ground center-of-gravity location, Zup, that is less than about 13.5 to 18 mm; anda center of gravity located horizontally rearward of a center of the face of the golf club head of less than about 10 to 40 mm.

DETAILED DESCRIPTION

The following describes embodiments of golf club heads for metalwood type golf clubs, including drivers, fairway woods, rescue clubs, hybrid clubs, and the like. Several of the golf club heads incorporate features that provide the golf club heads and/or golf clubs with increased moments of inertia and low centers of gravity, centers of gravity located in preferable locations, improved golf club head and face geometries, increased sole and lower face flexibility, higher coefficients or restitution (“COR”) and characteristic times (“CT”), and/or decreased backspin rates relative to fairway wood and other golf club heads that have come before.

This disclosure describes embodiments of golf club heads in the context of fairway wood-type golf clubs, but the principles, methods and designs described may be applicable in whole or in part to other wood-type golf clubs, such as drivers, utility clubs (also known as hybrid clubs), rescue clubs, and the like.

The disclosed inventive features include all novel and non-obvious features disclosed herein, both alone and in novel and non-obvious combinations with other elements. As used herein, the phrase “and/or” means “and,” “or” and both “and” and “or.” As used herein, the singular forms “a,” “an” and “the” refer to one or more than one, unless the context clearly dictates otherwise. As used herein, the terms “including” and “having” (and their grammatical variants) mean “comprising.”

This disclosure also refers to the accompanying drawings, which form a part hereof. The drawings illustrate specific embodiments, but other embodiments may be formed and structural changes may be made without departing from the intended scope of this disclosure and the technology discussed herein. Directions and references (e.g., up, down, top, bottom, left, right, rearward, forward, heelward, toeward, etc.) may be used to facilitate discussion of the drawings but are not intended to be limiting. For example, certain terms may be used such as “up,” “down,” “upper,” “lower,” “horizontal,” “vertical,” “left,” “right” and the like. These terms are used where applicable, to provide some clarity of description when dealing with relative relationships, particularly with respect to the illustrated embodiments. Such terms are not, however, intended to imply absolute relationships, positions and/or orientations, unless otherwise indicated. For example, with respect to an object, an “upper” surface can become a “lower” surface simply by turning the object over. Nevertheless, it is still the same object. Accordingly, the following detailed description shall not be construed in a limiting sense and the scope of property rights sought shall be defined by the appended claims and their equivalents.

Golf club heads and many of their physical characteristics disclosed herein will be described using “normal address position” as the golf club head reference position, unless otherwise indicated.FIG. 9illustrates one embodiment of a fairway wood type golf club head at normal address position. At normal address position, the golf club head10rests on a ground plane17, a plane parallel to the ground.

As used herein, “normal address position” means the golf club head position wherein a vector normal to the face plate34substantially lies in a first vertical plane (i.e., a vertical plane is perpendicular to the ground plane17, a centerline axis18of a club shaft substantially lies in a second vertical plane, and the first vertical plane and the second vertical plane intersect.

Golf club head “forgiveness” generally describes the ability of a golf club head to deliver a desirable golf ball trajectory despite a mis-hit (e.g., a ball struck at a location on the face plate34other than an ideal impact location). As described above, large mass moments of inertia contribute to the overall forgiveness of a golf club head. In addition, a low center-of-gravity improves forgiveness for golf club heads used to strike a ball from the turf by giving a higher launch angle and a lower spin trajectory (which improves the distance of a fairway wood golf shot). Providing a rearward center-of-gravity reduces the likelihood of a slice or fade for many golfers. Accordingly, forgiveness of fairway wood golf club heads, can be improved using the techniques described above to achieve high moments of inertia and low center-of-gravity compared to conventional fairway wood golf club heads.

For example, a golf club head with a crown thickness less than about 0.65 mm throughout at least about 70% of the crown can provide significant discretionary mass. A 0.60 mm thick crown can provide as much as about 8 grams of discretionary mass compared to a 0.80 mm thick crown. The large discretionary mass can be distributed to improve the mass moments of inertia and desirably locate the golf club head center-of-gravity. Generally, discretionary mass should be located sole-ward rather than crown-ward to maintain a low center-of-gravity, forward rather than rearward to maintain a forwardly positioned center of gravity, and rearward rather than forward to maintain a rearwardly positioned center-of-gravity. In addition, discretionary mass should be located far from the center-of-gravity and near the perimeter of the golf club head to maintain high mass moments of inertia.

Another parameter that contributes to the forgiveness and successful playability and desirable performance of a golf club is the coefficient of restitution (COR) of the golf club head. Upon impact with a golf ball, the golf club head's face plate deflects and rebounds, thereby imparting energy to the struck golf ball. The golf club head's coefficient of restitution (COR) is the ratio of the velocity of separation to the velocity of approach. A thin face plate generally will deflect more than a thick face plate. Thus, a properly constructed club with a thin, flexible face plate can impart a higher initial velocity to a golf ball, which is generally desirable, than a club with a thick, rigid face plate. In order to maximize the moment of inertia (MOI) about the center of gravity (CG) and achieve a high COR, it typically is desirable to incorporate thin walls and a thin face plate into the design of the golf club head. Thin walls afford the designers additional leeway in distributing golf club head mass to achieve desired mass distribution, and a thinner face plate may provide for a relatively higher COR.

Thus, thin walls are important to a club's performance. However, overly thin walls can adversely affect the golf club head's durability. Problems also arise from stresses distributed across the golf club head upon impact with the golf ball, particularly at junctions of golf club head components, such as the junction of the face plate with other golf club head components (e.g., the sole, skirt, and crown). One prior solution has been to provide a reinforced periphery about the face plate, such as by welding, in order to withstand the repeated impacts. Another approach to combat stresses at impact is to use one or more ribs extending substantially from the crown to the sole vertically, and in some instances extending from the toe to the heel horizontally, across an inner surface of the face plate. These approaches tend to adversely affect club performance characteristics, e.g., diminishing the size of the sweet spot, and/or inhibiting design flexibility in both mass distribution and the face structure of the golf club head. Thus, these golf club heads fail to provide optimal MOI, CG, and/or COR parameters, and as a result, fail to provide much forgiveness for off-center hits for all but the most expert golfers.

Thus, the golf clubs head of this disclosure are designed to allow for introduction of a face which can be adjusted in thickness as needed or desired to interact with the other disclosed aspects, such as a hollow front speed channel behind the face, as well as increased areas of mass and/or removable weights. The golf club heads of this disclosure may utilize, for example, the variable thickness face features described in U.S. patent application Ser. No. 12/006,060, U.S. Pat. Nos. 6,997,820, 6,800,038, and 6,824,475, which are incorporated herein by reference in their entirety. Additionally, the mass of the face, as well as other of the above-described properties can be adjusted by using different face materials, structures, and features, such as those described in U.S. patent application Ser. Nos. 11/998,435, 11/642,310, 11/825,138, 11/823,638, 12/004,386, 12/004,387, 11/960,609, 11/960,610 and U.S. Pat. No. 7,267,620, which are herein incorporated by reference in their entirety. Additionally, the structure of the front channel, club head face, and surrounding features of any of the embodiments herein can be varied to further impact COR and related aspects of the golf club head performance, as further described in U.S. patent application Ser. Nos. 13/839,727 and 14/457883, which are incorporated by reference herein in their entirety.

In addition to the thickness of the face plate and the walls of the golf club head, the location of the center of gravity also has a significant effect on the COR of a golf club head. For example, a given golf club head having a given CG will have a projected center of gravity or “balance point” or “CG projection” that is determined by an imaginary line passing through the CG and oriented normal to the face plate34. The location where the imaginary line intersects the face plate34is the CG projection, which is typically expressed as a distance above or below the center of the face plate34. When the CG projection is well above the center of the face, impact efficiency, which is measured by COR, is not maximized. It has been discovered that a fairway wood with a relatively lower CG projection or a CG projection located at or near the ideal impact location on the striking surface of the club face, as described more fully below, improves the impact efficiency of the golf club head as well as initial ball speed. One important ball launch parameter, namely ball spin, is also improved.

Fairway wood shots typically involve impacts that occur below the center of the face, so ball speed and launch parameters are often less than ideal. This results because most fairway wood shots are from the ground and not from a tee, and most golfers have a tendency to hit their fairway wood ground shots low on the face of the golf club head. Maximum ball speed is typically achieved when the ball is struck at the location on the striking face where the COR is greatest.

For traditionally designed fairway woods, the location where the COR is greatest is the same as the location of the CG projection on the striking surface. This location, however, is generally higher on the striking surface than the below center location of typical ball impacts during play. In contrast to these conventional golf clubs, it has been discovered that greater shot distance is achieved by configuring the golf club head to have a CG projection that is located near to the center of the striking surface of the golf club head.

It is known that the coefficient of restitution (COR) of a golf club may be increased by increasing the height Hssof the face plate34and/or by decreasing the thickness of the face plate34of a golf club head. However, in the case of a fairway wood, hybrid, or rescue golf club, increasing the face height may be considered undesirable because doing so will potentially cause an undesirable change to the mass properties of the golf club (e.g., center of gravity location) and to the golf club's appearance.

The United States Golf Association (USGA) regulations constrain golf club head shapes, sizes, and moments of inertia. Due to theses constraints, golf club manufacturers and designers struggle to produce golf club heads having maximum size and moment of inertia characteristics while maintaining all other golf club head characteristics. For example, one such constraint is a volume limitation of 460 cm3. In general, volume is measured using the water displacement method. However, the USGA will fill any significant cavities in the sole or series of cavities which have a collective volume of greater than 15 cm3.

To produce a more forgiving golf club head designers struggle to maximize certain parameters such as face area, moment of inertia about the z-axis and x-axis, and address area. A larger face area makes the golf club head more forgiving. Likewise, higher moment of inertia about the z-axis and x-axis makes the golf club head more forgiving. Similarly, a larger front to back dimension will generally increase moment of inertia about the z-axis and x-axis because mass is moved further from the center of gravity and the moment of inertia of a mass about a given axis is proportional to the square of the distance of the mass away from the axis. Additionally, a larger front to back dimension will generally lead to a larger address area which inspires confidence in the golfer when s/he addresses the golf ball.

However, when designers seek to maximize the above parameters it becomes difficult to stay within the volume limits and golf club head mass targets. Additionally, the sole curvature begins to flatten as these parameters are maximized. A flat sole curvature provides poor acoustics. To counteract this problem, designers may add a significant amount of ribs to the internal cavity to stiffen the overall structure and/or thicken the sole material to stiffen the overall structure. See for exampleFIGS. 55C and 55Dand the corresponding text of U.S. Publication No. 2016/0001146 A1, published Jan. 7, 2016. This, however, wastes discretionary mass that could be put elsewhere to improve other properties like moment of inertia about the z-axis and x-axis.

A golf club head Characteristic Time (CT) can be described as a numerical characterization of the flexibility of a golf club head striking face. The CT may also vary at points distant from the center of the striking face, but may not vary greater than approximately 20% of the CT as measured at the center of the striking face. The CT values for the golf club heads described in the present application were calculated based on the method outlined in the USGA “Procedure for Measuring the Flexibility of a Golf Clubhead,” Revision 2.0, Mar. 25, 2005, which is incorporated by reference herein in its entirety. Specifically, the method described in the sections entitled “3. Summary of Method,” “5. Testing Apparatus Set-up and Preparation,” “6. Club Preparation and Mounting,” and “7. Club Testing” are exemplary sections that are relevant. Specifically, the characteristic time is the time for the velocity to rise from 5% of a maximum velocity to 95% of the maximum velocity under the test set forth by the USGA as described above.

FIGS. 1-10illustrate an exemplary golf club head10that embodies certain inventive technologies disclosed herein. This exemplary embodiment of a golf club head provides increased COR by increasing or enhancing the perimeter flexibility of a face plate34of the golf club without necessarily increasing the height or decreasing the thickness of the face plate34. For example,FIG. 1is a bottom perspective view of a golf club head10having a high COR. The golf club head10comprises a body12(shown isolated inFIGS. 4, 7A, and 10), a hosel14(illustrated inFIGS. 3 and 8A) comprising a hosel bore15, in which a golf club shaft may be inserted and secured to the golf club head10, and a crown insert32(seeFIGS. 2 and 3) that is attached to the top of the body12. The golf club head10defines a front end or face20, rear end22, toe side24, heel side26, lower side or sole30, and upper side or crown28(all embodiments disclosed herein share similar directional references).

The front end20includes a face plate34(FIG. 2) for striking a golf ball, which may be an integral part of the body12or a separate insert. Though not shown, the front end20can include a face opening to receive a face plate34that is attached to the body by welding, braising, soldering, screws or other fastening means. A skirt portion29extends around the periphery of the club head between the sole30and crown28and excluding the face plate34.

Near the face plate34, a front channel36is formed in the sole30. As illustrated inFIG. 6, the channel36extends into an interior cavity13of the golf club head10, and so, as illustrated inFIG. 3, may be provided with a slot insert48to prevent dirt, grass, or other elements from entering the interior of the body12. The front channel36extends in the toe-heel directions across the sole, with a heelward end38near the hosel14and an opposite toeward end40. The front channel can improve coefficient of restitution (COR) across the striking face and can provide increased forgiveness on off-center ball strikes. For example, the presence of the front channel can expand zones of the highest COR across the face of the club, particularly at the bottom of the club face near the channel, so that a larger fraction of the face area has a COR above a desired value, especially at the lower regions of the face. More information regarding the construction and performance benefits of the front channel36and similar front channels can be found in U.S. Pat. No. 8,870,678 and U.S. Publication Nos. 2016/0059094 A1, published March 3, 2016, 2016/0023060 A1, published Jan. 28, 2016, and 2016/0023063 A1, published Jan. 28, 2016, all of which are incorporated by reference herein in their entireties, and various of the other publications that are incorporated by reference herein.

As best illustrated inFIG. 4, a forward mass pad42is separated from and positioned rearward of the channel36, and a second, rearward mass pad44is positioned near the rear sole surface46and formed integrally with the rear end22of the golf club head10. Exemplary embodiments of the structure of the forward mass pad42are further described herein. In the illustrated embodiment, the rearward mass pad44is shown as being formed on the heel side26of the golf club head10, though in other embodiments, it might be situated closer to the center of the rear end22of the golf club head10, or even on the toe side24, of the golf club head10.

The body12can include a front ground contact surface54on the body forward of the front channel36adjacent the bottom of the face plate34. The body can also have an intermediate ground contact surface, or sit pad,50rearward of the channel36. The intermediate ground contact surface50can have an elevation and curvature congruent with that of the front ground contact surface54. The body12can further comprise a downwardly extending rear sole surface46that extends around the perimeter of the rear end22of the body. In some embodiments, the rear sole surface46can act as a ground contact or sit pad as well, having a curvature and elevation congruent with that of the front ground contact surface54and the intermediate ground contact surface50.

The body12can further include a raised sole portion52that is recessed up from the intermediate ground contact surface50and from the rear sole surface46. The raised sole portion52can span over any portion of the sole30, and in the illustrated embodiment the raised sole portion52spans over most of the rearward portion of the sole. The sole30can include a sloped transition portion53where the intermediate ground contact surface50transitions up to the raised sole portion52. The sole can also include other similar sloped portions (not shown), such as around the boundary of the raised sole portion52. In some embodiments, as illustrated, one or more cantilevered ribs or struts58can be included on the sole that span from the sloped transition portion53to the raised sole portion52, to provide increased stiffness and rigidity to the sole.

The raised sole portion52can optionally include grooves, channels, ridges, or other surface features that increase its rigidity, such as groove74and ridge76, best illustrated inFIG. 7B. Similarly, the intermediate ground contact surface50can include stiffening surface features, such as ridges78and80, though grooves or other stiffening features can be substituted for the ridges.

A sole such as the sole30of the golf club head10may be referred to as a two-tier construction, bi-level construction, raised sole construction, or dropped sole construction, in which one portion of the sole is raised or recessed relative to the other portion of the sole. The terms raised, lowered, recessed, dropped, etc. are relative terms depending on perspective. For example, the intermediate ground contact surface50could be considered “raised” relative to the raised sole portion52when the head is upside down with the sole facing upwardly as inFIG. 1. On the other hand, the intermediate ground contact surface50portion can also be considered a “dropped sole” part of the sole, since it is located closer to the ground relative to the raised sole portion52when the golf club head is in a normal address position with the sole facing the ground.

Additional disclosure regarding the use of recessed or dropped soles is provided in U.S. Provisional Patent Application No. 62/515,401, filed on Jun. 5, 2017, the entire disclosure of which is incorporated herein by reference.

The raised sole constructions described herein and in the incorporated references are counterintuitive because the raised portion of the sole tends to raise the Iyy position), which is sometimes considered disadvantageous. However, the raised sole portion52(and other raised sole portion embodiments disclosed herein) allows for a smaller radius of curvature for that portion of the sole (compared to a conventional sole without the raised sole portion) resulting in increased rigidity and better acoustic properties due to the increased stiffness from the geometry. This stiffness increase means fewer ribs or even no ribs are needed in that portion of the sole to achieve a desired first mode frequency, such as 3000 Hz or above, 3200 Hz or above, or even 3400 Hz or above. Fewer ribs provides a mass/weight savings, which allows for more discretionary mass that can be strategically placed elsewhere in the golf club head or incorporated into user adjustable movable weights.

Furthermore, the sloped transition portions53,55around the raised sole portion52, as well as groove74and ridge76, respectively, and the optional ribs, e.g., rib58, can provide additional structural support and additional rigidity for the golf club head, and can also modify and even fine tune the acoustic properties of the golf club head. The sound and modal frequencies emitted by the golf club head when it strikes a golf ball are very important to the sensory experience of a golfer and provide functional feedback as to where the ball impact occurs on the face (and whether the ball is well struck).

In some embodiments, the raised sole portion52can be made of a relatively thinner and/or less dense material compared to other portions of the sole and body that take more stress, such as the ground contact surfaces46,54,50, the face region, and the hosel region. By reducing the mass of the raised sole portion52, the higher CG effect of raising that portion of the sole is mitigated while maintaining a stronger, heavier material on other portions of the sole and body to promote a lower CG and provide added strength in the area of the sole and body where it is most needed (e.g., in a sole region proximate to the hosel and around the face and shaft connection components where stress is higher).

The body12can also include one or more internal ribs, such as rib82, as best shown inFIGS. 4 and 7A, that are integrally formed with or attached to the inner surfaces of the body. Such ribs can vary in size, shape, location, number and stiffness, and can be used strategically to reinforce or stiffen designated areas of the body's interior and/or fine tune acoustic properties of the golf club head.

Generally, the center of gravity (CG) of a golf club head is the average location of the weight of the golf club head or the point at which the entire weight of the golf club-head may be considered as concentrated so that if supported at this point the head would remain in equilibrium in any position. A golf club head origin coordinate system can be defined such that the location of various features of the golf club head, including the CG can be determined with respect to a golf club head origin positioned at the geometric center of the striking surface and when the club-head is at the normal address position (i.e., the club-head position wherein a vector normal to the club face substantially lies in a first vertical plane perpendicular to the ground plane, the centerline axis of the club shaft substantially lies in a second substantially vertical plane, and the first vertical plane and the second substantially vertical plane substantially perpendicularly intersect).

The head origin coordinate system defined with respect to the head origin includes three axes: a z-axis extending through the head origin in a generally vertical direction relative to the ground; an x-axis extending through the head origin in a toe-to-heel direction generally parallel to the striking surface (e.g., generally tangential to the striking surface at the center) and generally perpendicular to the z-axis; and a y-axis extending through the head origin in a front-to-back direction and generally perpendicular to the x-axis and to the z-axis. The x-axis and the y-axis both extend in generally horizontal directions relative to the ground when the golf club head is at the normal address position. The x-axis extends in a positive direction from the origin towards the heel of the golf club head. The y axis extends in a positive direction from the head origin towards the rear portion of the golf club head. The z-axis extends in a positive direction from the origin towards the crown. Thus for example, and using millimeters as the unit of measure, a CG that is located 3.2 mm from the head origin toward the toe of the golf club head along the x-axis, 36.7 mm from the head origin toward the rear of the clubhead along the y-axis, and 4.1 mm from the head origin toward the sole of the golf club head along the z-axis can be defined as having a CGxof −3.2 mm, a CGyof −36.7 mm, and a CGzof −4.1 mm.

Further as used herein, Delta 1 is a measure of how far rearward in the golf club head body the CG is located. More specifically, Delta 1 is the distance between the CG and the hosel axis along the y axis (in the direction straight toward the back of the body of the golf club face from the geometric center of the striking face). It has been observed that smaller values of Delta 1 result in lower projected CGs on the golf club head face. Thus, for embodiments of the disclosed golf club heads in which the projected CG on the ball striking club face is lower than the geometric center, reducing Delta 1 can lower the projected CG and increase the distance between the geometric center and the projected CG. Note also that a lower projected CG can create a higher dynamic loft and more reduction in backspin due to the z-axis gear effect. Thus, for particular embodiments of the disclosed golf club heads, in some cases the Delta 1 values are relatively low, thereby reducing the amount of backspin on the golf ball helping the golf ball obtain the desired high launch, low spin trajectory.

Similarly Delta 2 is the distance between the CG and the hosel axis along the x axis (in the direction straight toward the back of the body of the golf club face from the geometric center of the striking face).

Adjusting the location of the discretionary mass in a golf club head as described herein can provide the desired Delta 1 value. For instance, Delta 1 can be manipulated by varying the mass in front of the CG (closer to the face) with respect to the mass behind the CG. That is, by increasing the mass behind the CG with respect to the mass in front of the CG, Delta 1 can be increased. In a similar manner, by increasing the mass in front of the CG with the respect to the mass behind the CG, Delta 1 can be decreased.

In addition to the position of the CG of a club-head with respect to the head origin another important property of a golf club-head is a projected CG point on the golf club head striking surface which is the point on the striking surface that intersects with a line that is normal to the tangent line of the ball striking club face and that passes through the CG. This projected CG point (“CG Proj”) can also be referred to as the “zero-torque” point because it indicates the point on the ball striking club face that is centered with the CG. Thus, if a golf ball makes contact with the club face at the projected CG point, the golf club head will not twist about any axis of rotation since no torque is produced by the impact of the golf ball. A negative number for this property indicates that the projected CG point is below the geometric center of the face.

In terms of the MOI of the club-head (i.e., a resistance to twisting) it is typically measured about each of the three main axes of a club-head with the CG as the origin of the coordinate system. These three axes include a CG z-axis extending through the CG in a generally vertical direction relative to the ground when the golf club head is at normal address position; a CG x-axis extending through the CG origin in a toe-to-heel direction generally parallel to the striking surface (e.g., generally tangential to the striking surface at the club face center), and generally perpendicular to the CG z-axis; and a CG y-axis extending through the CG origin in a front-to-back direction and generally perpendicular to the CG x-axis and to the CG z-axis. The CG x-axis and the CG y-axis both extend in generally horizontal directions relative to the ground when the golf club head is at normal address position. The CG x-axis extends in a positive direction from the CG origin to the heel of the golf club head. The CG y-axis extends in a positive direction from the CG origin towards the rear portion of the golf club head. The CG z-axis extends in a positive direction from the CG origin towards the crown. Thus, the axes of the CG origin coordinate system are parallel to corresponding axes of the head origin coordinate system. In particular, the CG z-axis is parallel to z-axis, the CG x-axis is parallel to x-axis, and CG y-axis is parallel to y-axis.

Specifically, a golf club head as a moment of inertia about the vertical axis (“Izz”), a moment of inertia about the heel/toe axis (“Ixx”), and a moment of inertia about the front/back axis (“Iyy”). Typically, however, the MOI about the z-axis (Izz) and the x-axis (Ixx) is most relevant to golf club head forgiveness.

A moment of inertia about the golf club head CG x-axis (Ixx) is calculated by the following equation:
Ixx=∫(y2+z2)dm
where y is the distance from a golf club head CG xz-plane to an infinitesimal mass dm and z is the distance from a golf club head CG xy-plane to the infinitesimal mass dm. The golf club head CG xz-plane is a plane defined by the golf club head CG x-axis and the golf club head CG z-axis. The CG xy-plane is a plane defined by the golf club head CGx-axis and the golf club head CG y-axis.

Similarly, a moment of inertia about the golf club head CG z-axis (Izz) is calculated by the following equation:
Izz=∫(x2+y2)dm
where x is the distance from a golf club head CG yz-plane to an infinitesimal mass dm and y is the distance from the golf club head CG xz-plane to the infinitesimal mass dm. The golf club head CG yz-plane is a plane defined by the golf club head CG y-axis and the golf club head CG z-axis.

A further description of the coordinate systems for determining CG positions and MOI can be found US Patent Publication No. 2012/0172146 A1, published on Jul. 5, 2012, the entire contents of which is incorporated by reference herein.

As used herein, “Zup” means the CG z-axis location determined according to the above ground coordinate system. Zup generally refers to the height of the CG above the ground plane17.

As described herein, desired golf club head mass moments of inertia, golf club head center-of-gravity locations, and other mass properties of a golf club head can be attained by distributing golf club head mass to particular locations. Discretionary mass generally refers to the mass of material that can be removed from various structures providing mass that can be distributed elsewhere for tuning one or more mass moments of inertia and/or locating the golf club head center-of-gravity.

Golf club head walls provide one source of discretionary mass. In other words, a reduction in wall thickness reduces the wall mass and provides mass that can be distributed elsewhere. Thin walls, particularly a thin crown28, provide significant discretionary mass compared to conventional golf club heads. For example, a golf club head made from an alloy of steel can achieve about 4 grams of discretionary mass for each 0.1 mm reduction in average crown thickness. Similarly, a golf club head made from an alloy of titanium can achieve about 2.5 grams of discretionary mass for each 0.1 mm reduction in average crown thickness. Discretionary mass achieved using a thin crown, e.g., less than about 0.65 mm, can be used to tune one or more mass moments of inertia and/or center-of-gravity location.

To achieve a thin wall on the golf club head body10, such as a thin crown28, a golf club head body10can be formed from an alloy of steel or an alloy of titanium. For further details concerning titanium casting, please refer to U.S. Pat. No. 7,513,296, incorporated herein by reference.

Various approaches can be used for positioning discretionary mass within a golf club head. For example, golf club heads may have one or more integral mass pads cast into the head at predetermined locations that can be used to lower, to move forward, to move rearward, or otherwise to adjust the location of the golf club head's center-of-gravity, as further described herein. Also, epoxy can be added to the interior of the golf club head, such as through a hosel bore15(illustrated inFIGS. 5, 6, 7A, 8A, and 8B) in the golf club head to obtain a desired weight distribution. Alternatively, weights formed of high-density materials can be attached to the sole, skirt, and other parts of a golf club head. With such methods of distributing the discretionary mass, installation is critical because the golf club head endures significant loads during impact with a golf ball that can dislodge the weight. Accordingly, such weights are usually permanently attached to the golf club head and are limited to a fixed total mass, which of course, permanently fixes the golf club head's center-of-gravity and moments of inertia.

For example,FIG. 4illustrates a cross-section of the golf club head10ofFIG. 1. In the illustrated embodiment, in addition to the rearward mass pad44described previously, the forward mass pad42further comprises three separate sections, all of which are integrally formed into a single structure. Alternatively, the three sections may be formed separately, but placed in contact, or in close proximity to one another. While three sections are illustrated, it is understood that more or fewer sections may be formed. The first section, heel mass section64, is positioned adjacent the heel side26of the golf club head10, and comprises a first heel mass portion66nearest the heel side26, having a first forward to rearward dimension. The heel mass section64further comprises a second heel mass portion68that is further from the heel side26than the first heel mass portion66, and has a second forward to rearward dimension. In the illustrated embodiment, this second forward to rearward dimension is smaller than the first forward to rearward dimension, though these relative dimensions could be reversed. Further, heel mass section64has a vertical height that may be higher in the first heel mass portion66near the heel side26and may slope downward toward the second heel mass portion68. Additionally, the heel mass section64may have one or more edges that slope downward from a first vertical height to an edge portion that makes contact with the sole30.

Opposite the heel mass section64and adjacent the toe side24of the golf club head10is a second, toe mass section84, which comprises a first toe mass portion86nearest the toe side24, having a third forward to rearward dimension. In the illustrated embodiment this third forward to rearward dimension is shown as similar to the first forward to rearward dimension of the first heel mass portion66, but these first and third forward to rearward dimensions may in some cases be different. The toe mass section84further comprises a second toe mass portion88that is further from the toe side24than the first toe mass portion86, and has a fourth forward to rearward dimension. In the illustrated embodiment, this fourth forward to rearward dimension is smaller than the third forward to rearward dimension, though these relative dimensions could be reversed. In the illustrated embodiment this fourth forward to rearward dimension is shown as similar to the second forward to rearward dimension of the second heel mass portion68, but these first and third forward to rearward dimensions may in some cases be different. Further, toe mass section84has a vertical height that may be higher in the first toe mass portion86near the toe side24and may slope downward toward the second toe mass portion88. Additionally, the toe mass section84may have one or more edges that slope downward from a first vertical height to an edge portion that makes contact with the sole30.

Positioned in between the heel mass section64and toe mass section84is a third, middle mass section94, which in the illustrated embodiment has a fifth forward to rearward dimension that is smaller than any of the four forward to rearward dimensions described for the heel mass section64and toe mass section84. However, in other embodiments, the middle mass section94could have a similar dimension to, e.g., the second toe mass portion88and the second heel mass portion68. Also shown in the illustrated embodiment, the smaller forward to rearward dimension of the middle mass section94provides a void96between the heel mass section64and the toe mass section84. Additionally, the middle mass section94in the illustrated embodiment has a smaller mass than the heel mass section64and toe mass section84, providing increased perimeter weighting, which can increase the mass moment of inertia of the golf club head, particularly the moments of inertia about the CG z-axis, Izz, and the CG x-axis, Ixx. For example, splitting the forward mass pad42into areas of larger mass offset from a center of gravity of the club, as with heel mass section64and toe mass section84, may increase the moment of inertia about the CG z-axis, Izz, and the CG x-axis, Ixx by about 10 percent, or in some instances eight percent, or in some instances six percent, or in some instances five percent, versus designs which do not implement such a split mass approach. And, generally moving mass rearward and to the perimeter of the golf club head generally may favorably increases the moment of inertia of the golf club head. The mass for the heel mass section64and toe mass section84may be similar, or alternatively, may be weighted differently, depends on the needs of the club designer. Similarly, each of the first heel mass portion66and the first toe mass portion86has a greater mass than their corresponding second heel mass portion68and second toe mass portion88, again moving additional discretionary mass to the perimeter of the club, further increasing the mass moment of inertia of the golf club head, particularly the moments of inertia about the CG z-axis, Izz, and the CG x-axis, Ixx.

As shown inFIGS. 2, 3, and 5, the golf club head10can optionally include a separate crown insert32that is secured to the body12, such as by applying a layer of epoxy adhesive33or other securement means, such as bolts, rivets, snap fit, other adhesives, or other joining methods or any combination thereof, to cover a large opening60at the top and rear of the body, forming part of the crown28of the golf club head. The crown insert32covers a substantial portion of the crown's surface area as, for example, at least 40%, at least 60%, at least 70% or at least 80% of the crown's surface area. The crown's outer boundary generally terminates where the crown surface undergoes a significant change in radius of curvature, e.g., near where the crown transitions to the golf club head's sole30, hosel14, and front end20.

As best illustrated inFIG. 7A, the crown opening60can be formed to have a recessed peripheral ledge or seat62to receive the crown insert32, such that the crown insert is either flush with the adjacent surfaces of the body to provide a smooth seamless outer surface or, alternatively, slightly recessed below the body surfaces. The front of the crown insert32can join with a front portion of the crown28on the body to form a continuous, arched crown extend forward to the face. The crown insert32can comprise any suitable material (e.g., lightweight composite and/or polymeric materials) and can be attached to the body in any suitable manner, as described in more detail elsewhere herein.

A wood-type golf club head, such as golf club head10and the other wood-type club heads disclosed herein have a volume, typically measured in cubic-centimeters (cm3) equal to the volumetric displacement of the club head, assuming any apertures are sealed by a substantially planar surface. (See United States Golf Association “Procedure for Measuring the Club Head Size of Wood Clubs,” Revision 1.0, Nov. 21, 2003). In other words, for a golf club head with one or more weight ports within the head, it is assumed that the weight ports are either not present or are “covered” by regular, imaginary surfaces, such that the club head volume is not affected by the presence or absence of ports.

In some embodiments, as in the case of a fairway wood (as illustrated), the golf club head may have a volume between about 100 cm3and about 300 cm3, such as between about 150 cm3and about 250 cm3, or between about 125 cm3and about 240 cm3, and a total mass between about 125 g and about 260 g. In the case of a utility or hybrid club (analogous to the illustrated embodiments), the golf club head may have a volume between about 60 cm3and about 150 cm3, and a total mass between about 125 g and about 280 g. In the case of a driver (analogous to the illustrated embodiments), any of the disclosed golf club heads can have a volume between about 300 cm3and about 600 cm3, between about 350 cm3and about 600 cm3, and/or between about 350 cm3and about 500 cm3, and can have a total mass between about 145 g and about 260 g, such as between about 195 g and about 205 g.

As illustrated inFIGS. 8A and 8B, the hosel bore15may pass through the hosel and open up into the interior cavity13of the body12. As further illustrated inFIG. 8B, the hosel14may have a plurality of indentations16around its circumference, which reduces the overall mass of the hosel14, and thus the golf club head10, freeing up additional discretionary mass, and also providing for greater flexibility and “give” of the golf club head10when affixed to a golf club shaft (not pictured).

Additionally, the thickness of the hosel may be varied to provide for additional discretionary mass, as described in U.S. patent application Ser. No. 14/981,330, the entire disclosure of which is hereby incorporated by reference.

In some of the embodiments described herein, a comparatively forgiving golf club head for a fairway wood can combine an overall golf club head height (Hch) of less than about 46 mm and an above ground center-of-gravity location, Zup, less than about 18 mm. Some examples of the golf club head provide an above ground center-of-gravity location, Zup, less than about 17 mm, less than about 16 mm, less than about 15.5 mm, less than about 15.5 mm, less than about 15.0 mm, less than about 14.5 mm, less than about 14.0 mm, or less than about 13.5 mm.

In addition, a thin crown28as described above provides sufficient discretionary mass to allow the golf club head to have a volume less than about 240 cm3and/or a front to back depth (Dch) greater than about 85 mm. Without a thin crown28, a similarly sized golf club head would either be overweight or would have an undesirably located center-of-gravity because less discretionary mass would be available to tune the CG location.

In addition, in some embodiments of a comparatively forgiving golf club head, discretionary mass can be distributed to provide a mass moment of inertia about the CG z-axis, Izz, greater than about 170 kg-mm2. In some instances, the mass moment of inertia about the CG z-axis, Izz, can be greater than about 300 kg-mm2, such as greater than about 320 kg-mm2, greater than about 340 kg-mm2, greater than about 360 kg-mm2, or greater than about 375 kg-mm2. Distribution of the discretionary mass can also provide a mass moment of inertia about the CG x-axis, Ixx, greater than about 70 kg-mm2. In some instances, the mass moment of inertia about the CG x-axis, Ixx, can be greater than about 100 kg-mm2, such as greater than about 150 kg-mm2, greater than about 200 kg-mm2, or greater than about 220 kg-mm2.

Alternatively, some examples of a forgiving golf club head combine an above ground center-of-gravity location, Zup, less than about 18 mm, and a high moment of inertia about the CG z-axis, Izz.

Distribution of the discretionary mass can also provide a center of gravity for the golf club head10located horizontally rearward of a center of the face20of less than about 40 mm, such as less than about 10 to 40 mm, less than about 20 to 40 mm, less than about 20 to 30 mm, less than about 15 to 30 mm, or less than about 18 to 25 mm.

The crown insert32, disclosed in various embodiments herein, can help overcome manufacturing challenges associated with conventional golf club heads having normal continuous crowns made of titanium or other metals, and can replace a relatively heavy component of the crown with a lighter material, freeing up discretionary mass which can be strategically allocated elsewhere within the golf club head. In certain embodiments, the crown may comprise a composite material, such as those described herein and in the incorporated disclosures, such as a composite material having a density of less than 2 grams per cubic centimeter. In still further embodiments, the material has a density of less than 1.5 grams per cubic centimeter, or a density between 1 gram per cubic centimeter and 2 grams per cubic centimeter. Providing a lighter crown further provides the golf club head with additional discretionary mass, which can be used elsewhere within the golf club head to serve the purposes of the designer. For example, with the discretionary mass, additional ribs82can be strategically added to the hollow interior of the golf club head and thereby improve the acoustic properties of the head. Discretionary mass in the form of ribs, mass pads or other features also can be strategically located in the interior of the golf club head to shift the effective CG fore or aft, toeward or heelward or both (apart from any further CG adjustments made possible by adjustable weight features) or to improve desirable MOI characteristics, as further described herein.

Methods of making any of the golf club heads disclosed herein, or associated golf clubs, may include one or more of the following steps:forming a frame having a sole opening, forming a composite laminate sole insert, injection molding a thermoplastic composite head component over the sole insert to create a sole insert unit, and joining the sole insert unit to the frame, as described in more detail in the incorporated U.S. Provisional Patent Application No. 62/440,886;providing a composite head component which is a weight track capable of supporting one or more slidable weights;forming the sole insert from a thermoplastic composite material having a matrix compatible for bonding with the weight track;forming the sole insert from a continuous fiber composite material having continuous fibers selected from the group consisting of glass fibers, aramide fibers, carbon fibers and any combination thereof, and having a thermoplastic matrix consisting of polyphenylene sulfide (PPS), polyamides, polypropylene, thermoplastic polyurethanes, thermoplastic polyureas, polyamide-amides (PAI), polyether amides (PEI), polyetheretherketones (PEEK), and any combinations thereof, wherein the sole insert is formed from a composite material having a density of less than 2 grams per cubic centimeter. In still further embodiments, the material has a density of less than 1.5 grams per cubic centimeter, or a density between 1 gram per cubic centimeter and 2 grams per cubic centimeter and the sole insert has a thickness of from about 0.195 mm to about 0.9 mm, preferably from about 0.25 mm to about 0.75 mm, more preferably from about 0.3 mm to about 0.65 mm, even more preferably from about 0.36 mm to about 0.56 mm;forming both the sole insert and weight track from thermoplastic composite materials having a compatible matrix;forming the sole insert from a thermosetting material, coating the sole insert with a heat activated adhesive, and forming the weight track from a thermoplastic material capable of being injection molded over the sole insert after the coating step;forming the frame from a material selected from the group consisting of titanium, one or more titanium alloys, aluminum, one or more aluminum alloys, steel, one or more steel alloys, and any combination thereof;forming the frame with a crown opening, forming a crown insert from a composite laminate material, and joining the crown insert to the frame such that the crown insert overlies the crown opening;selecting a composite head component from the group consisting of one or more ribs to reinforce the head, one or more ribs to tune acoustic properties of the head, one or more weight ports to receive a fixed weight in a sole portion of the club head, one or more weight tracks to receive a slidable weight, and combinations thereof;forming the sole insert and crown insert from a continuous carbon fiber composite material;forming the sole insert and crown insert by thermosetting using materials suitable for thermosetting, and coating the sole insert with a heat activated adhesive;forming the frame from titanium, titanium alloy or a combination thereof and has a crown opening, and the sole insert and weight track are each formed from a thermoplastic carbon fiber material having a matrix selected from the group consisting of polyphenylene sulfide (PPS), polyamides, polypropylene, thermoplastic polyurethanes, thermoplastic polyureas, polyamide-amides (PAI), polyether amides (PEI), polyetheretherketones (PEEK), and any combinations thereof; andforming the frame with a crown opening, forming a crown insert from a thermoplastic composite material, and joining the crown insert to the frame such that it overlies the crown opening.

The bodies of the golf club heads disclosed herein, and optionally other components of the club heads as well, serve as frames and may be made from a variety of different types of suitable materials. In some embodiments, for example, the body and/or other head components can be made of a metal material such as a titanium or titanium alloy (including but not limited to 6-4 titanium, 3-2.5, 6-4, SP700, 15-3-3-3, 10-2-3, or other alpha/near alpha, alpha-beta, and beta/near beta titanium alloys), or aluminum and aluminum alloys (including but not limited to 3000 series alloys, 5000 series alloys, 6000 series alloys, such as 6061-T6, and 7000 series alloys, such as 7075). The body may be formed by conventional casting, metal stamping or other known processes. The body also may be made of other metals as well as non-metals. The body can provide a framework or skeleton for the club head to strengthen the club head in areas of high stress caused by the golf ball's impact with the face, such as the transition region where the club head transitions from the face to the crown area, sole area and skirt area located between the sole and crown areas.

In some embodiments, the sole insert and/or crown insert of the club head may be made from a variety of composite materials and/or polymeric materials, such as from a thermoplastic material, preferably from a thermoplastic composite laminate material, and most preferably from a thermoplastic carbon composite laminate material. For example, the composite material may comprise an injection moldable material, thermoformable material, thermoset composite material or other composite material suitable for golf club head applications. One exemplary material is a thermoplastic continuous carbon fiber composite laminate material having long, aligned carbon fibers in a PPS (polyphenylene sulfide) matrix or base. One commercial example of this type of material, which is manufactured in sheet form, is TEPEX® DYNALITE 207 manufactured by Lanxess.

TEPEX® DYNALITE 207 is a high strength, lightweight material having multiple layers of continuous carbon fiber reinforcement in a PPS thermoplastic matrix or polymer to embed the fibers. The material may have a 54% fiber volume but other volumes (such as a volume of 42% to 57%) will suffice. The material weighs about 200 g/m2.

Another similar exemplary material which may be used for the crown insert and/or sole insert is TEPEX® DYNALITE 208. This material also has a carbon fiber volume range of 42% to 57%, including a 45% volume in one example, and a weight of 200 g/m2. DYNALITE 208 differs from DYNALITE 207 in that it has a TPU (thermoplastic polyurethane) matrix or base rather than a polyphenylene sulfide (PPS) matrix.

By way of example, the TEPEX® DYNALITE 207 sheet(s) (or other selected material such as DYNALITE 208) are oriented in different directions, placed in a two-piece (male/female) matched die, heated past the melt temperature, and formed to shape when the die is closed. This process may be referred to as thermoforming and is especially well-suited for forming sole and crown inserts.

Once the crown insert and/or sole insert are formed (separately) by the thermoforming process just described, each is cooled and removed from the matched die. The sole and crown inserts are shown as having a uniform thickness, which lends itself well to the thermoforming process and ease of manufacture. However, the sole and crown inserts may have a variable thickness to strengthen select local areas of the insert by, for example, adding additional plies in select areas to enhance durability, acoustic or other properties in those areas.

As shown inFIG. 3, with regard to the crown insert32, a crown insert and/or sole insert can have a complex three-dimensional curvature corresponding generally to the crown and sole shapes of a fairway wood-type club head and specifically to the design specifications and dimensions of the particular head designed by the manufacturer. It will be appreciated that other types of club heads, such as drivers, utility clubs (also known as hybrid clubs), rescue clubs, and the like may be manufactured using one or more of the principles, methods and materials described herein.

In an alternative embodiment, the sole insert and/or crown insert can be made by a process other than thermoforming, such as injection molding or thermosetting. In a thermoset process, the sole insert and/or crown insert may be made from prepreg plies of woven or unidirectional composite fiber fabric (such as carbon fiber) that is preimpregnated with resin and hardener formulations that activate when heated. The prepreg plies are placed in a mold suitable for a thermosetting process, such as a bladder mold or compression mold, and stacked/oriented with the carbon or other fibers oriented in different directions. The plies are heated to activate the chemical reaction and form the sole (or crown) insert. Each insert is cooled and removed from its respective mold.

The carbon fiber reinforcement material for the thermoset sole/crown insert may be a carbon fiber known as “34-700” fiber, available from Grafil, Inc., of Sacramento, Calif., which has a tensile modulus of 234 Gpa (34 Msi) and tensile strength of 4500 Mpa (650 Ksi). Another suitable fiber, also available from Grafil, Inc., is a carbon fiber known as “TR50S” fiber which has a tensile modulus of 240 Gpa (35 Msi) and tensile strength of 4900 Mpa (710 Ksi). Exemplary epoxy resins for the prepreg plies used to form the thermoset crown and sole inserts are Newport 301 and 350 and are available from Newport Adhesives & Composites, Inc., of Irvine, Calif.

In one example, the prepreg sheets have a quasi-isotropic fiber reinforcement of 34-700 fiber having an areal weight of about 70 g/m2and impregnated with an epoxy resin (e.g., Newport 301), resulting in a resin content (R/C) of about 40%. For convenience of reference, the primary composition of a prepreg sheet can be specified in abbreviated form by identifying its fiber areal weight, type of fiber, e.g., 70 FAW 34-700. The abbreviated form can further identify the resin system and resin content, e.g., 70 FAW 34-700/301, R/C 40%.

Once the sole insert and crown insert are formed, they can be joined to the body in a manner that creates a strong integrated construction adapted to withstand normal stress, loading and wear and tear expected of commercial golf clubs. For example, the sole insert and crown insert each may be bonded to the frame using epoxy adhesive, with the crown insert seated in and overlying the crown opening and the sole insert seated in and overlying the sole opening. Alternative attachment methods include bolts, rivets, snap fit, adhesives, other known joining methods or any combination thereof.

Of these preferred are polyamides (PA), polyphthalimide (PPA), polyketones (PK), copolyamides, polyesters, copolyesters, polycarbonates, polyphenylene sulfide (PPS), cyclic olefin copolymers (COC), polyphenylene oxides, diallylphthalate polymers, polyarylates, polyacrylates, polyphenylene ethers, and impact-modified polyphenylene ethers. Especially preferred polymers for use in the golf club heads of the present invention are the family of so called high performance engineering thermoplastics which are known for their toughness and stability at high temperatures. These polymers include the polysulfones, the polyetherimides, and the polyamide-imides. Of these, the most preferred are the polysufones.

Aromatic polysulfones are a family of polymers produced from the condensation polymerization of 4,4′-dichlorodiphenylsulfone with itself or one or more dihydric phenols. The aromatic polysulfones include the thermoplastics sometimes called polyether sulfones, and the general structure of their repeating unit has a diaryl sulfone structure which may be represented as -arylene-SO2-arylene-. These units may be linked to one another by carbon-to-carbon bonds, carbon-oxygen-carbon bonds, carbon-sulfur-carbon bonds, or via a short alkylene linkage, so as to form a thermally stable thermoplastic polymer. Polymers in this family are completely amorphous, exhibit high glass-transition temperatures, and offer high strength and stiffness properties even at high temperatures, making them useful for demanding engineering applications. The polymers also possess good ductility and toughness and are transparent in their natural state by virtue of their fully amorphous nature. Additional key attributes include resistance to hydrolysis by hot water/steam and excellent resistance to acids and bases. The polysulfones are fully thermoplastic, allowing fabrication by most standard methods such as injection molding, extrusion, and thermoforming. They also enjoy a broad range of high temperature engineering uses.

b) Polyethersulfone (PES also referred to as PESU); and

Particularly important and preferred aromatic polysulfones are those comprised of repeating units of the structure —C6H4SO2—C6H4—O-where C6H4represents an m-or p-phenylene structure. The polymer chain can also comprise repeating units such as —C6H4—, C6H4—O—, —C6H4-(lower-alkylene)-C6H4—O—, —C6H4—O—C6H4—O—, —C6H4—S—C6H4—O—, and other thermally stable substantially-aromatic difunctional groups known in the art of engineering thermoplastics. Also included are the so called modified polysulfones where the individual aromatic rings are further substituted in one or substituents including

wherein R is independently at each occurrence, a hydrogen atom, a halogen atom or a hydrocarbon group or a combination thereof. The halogen atom includes fluorine, chlorine, bromine and iodine atoms. The hydrocarbon group includes, for example, a C1-C20alkyl group, a C2-C20alkenyl group, a C3-C20cycloalkyl group, a C3-C20cycloalkenyl group, and a C6-C20aromatic hydrocarbon group. These hydrocarbon groups may be partly substituted by a halogen atom or atoms, or may be partly substituted by a polar group or groups other than the halogen atom or atoms. As specific examples of the C1-C20alkyl group, there can be mentioned methyl, ethyl, propyl, isopropyl, amyl, hexyl, octyl, decyl and dodecyl groups. As specific examples of the C2-C20alkenyl group, there can be mentioned propenyl, isopropepyl, butenyl, isobutenyl, pentenyland hexenyl groups. As specific examples of the C3-C20cycloalkyl group, there can be mentionedcyclopentyl and cyclohexyl groups. As specific examples of the C3-C20cycloalkenyl group, there can be mentioned cyclopentenyl and cyclohexenyl groups. As specific examples of the aromatic hydrocarbon group, there can be mentioned phenyl and naphthyl groups or a combination thereof.

(a) the polysulfone made by condensation polymerization of bisphenol A and 4,4′-dichlorodiphenyl sulfone in the presence of base, and having the main repeating structure

having the abbreviation PSF and sold under the tradenames Udel®, Ultrason® S, Eviva®, RTP PSU,

(b) the polysulfone made by condensation polymerization of 4,4′-dihydroxydiphenyl and 4,4′-dichlorodiphenyl sulfone in the presence of base, and having the main repeating structure

having the abbreviation PPSF and sold under the tradenames RADEL® resin; and

(c) a condensation polymer made from 4,4′-dichlorodiphenyl sulfone in the presence of base and having the principle repeating structure

having the abbreviation PPSF and sometimes called a “polyether sulfone” and sold under the tradenames Ultrason® E, LNP™, Veradel®PESU, Sumikaexce, and VICTREX® resin, “.and any and all combinations thereof.

In some embodiments, a composite material, such as a carbon composite, made of a composite including multiple plies or layers of a fibrous material (e.g., graphite, or carbon fiber including turbostratic or graphitic carbon fiber or a hybrid structure with both graphitic and turbostratic parts present. Examples of some of these composite materials for use in the metalwood golf clubs and their fabrication procedures are described in U.S. Pat. No. 7,267,620; U.S. Pat. No. 7,140,974; and U.S. patent application Ser. Nos. 11/642,310, 11/825,138, 11/998,436, 11/895,195, 11/823,638, 12/004,386, 12,004,387, 11/960,609, 11/960,610, and 12/156,947, which are all incorporated herein by reference. The composite material may be manufactured according to the methods described at least in U.S. patent application Ser. No. 11/825,138, the entire contents of which are herein incorporated by reference.

Alternatively, short or long fiber-reinforced formulations of the previously referenced polymers. Exemplary formulations include a Nylon 6/6 polyamide formulation which is 30% Carbon Fiber Filled and available commercially from RTP Company under the trade name RTP 285. The material has a Tensile Strength of 35000 psi (241 MPa) as measured by ASTM D 638; a Tensile Elongation of 2.0-3.0% as measured by ASTM D 638; a Tensile Modulus of 3.30×106psi (22754 MPa) as measured by ASTM D 638; a Flexural Strength of 50000 psi (345 MPa) as measured by ASTM D 790; and a Flexural Modulus of 2.60×106psi (17927 MPa) as measured by ASTM D 790.

Also included is a polyphthalamide (PPA) formulation which is 40% Carbon Fiber Filled and available commercially from RTP Company under the trade name RTP 4087 UP. This material has a Tensile Strength of 360 MPa as measured by ISO 527; a Tensile Elongation of 1.4% as measured by ISO 527; a Tensile Modulus of 41500 MPa as measured by ISO 527; a Flexural Strength of 580 MPa as measured by ISO 178; and a Flexural Modulus of 34500 MPa as measured by ISO 178.

Also included is a polyphenylene sulfide (PPS) formulation which is 30% Carbon Fiber Filled and available commercially from RTP Company under the trade name RTP 1385 UP. This material has a Tensile Strength of 255 MPa as measured by ISO 527; a Tensile Elongation of 1.3% as measured by ISO 527; a Tensile Modulus of 28500 MPa as measured by ISO 527; a Flexural Strength of 385 MPa as measured by ISO 178; and a Flexural Modulus of 23,000 MPa as measured by ISO 178.

An example is a polysulfone (PSU) formulation which is 20% Carbon Fiber Filled and available commercially from RTP Company under the trade name RTP 983. This material has a Tensile Strength of 124 MPa as measured by ISO 527; a Tensile Elongation of 2% as measured by ISO 527; a Tensile Modulus of 11032 MPa as measured by ISO 527; a Flexural Strength of 186 MPa as measured by ISO 178; and a Flexural Modulus of 9653 MPa as measured by ISO 178.

Another example is a polysulfone (PSU) formulation which is 30% Carbon Fiber Filled and available commercially from RTP Company under the trade name RTP 985. This material has a Tensile Strength of 138 MPa as measured by ISO 527; a Tensile Elongation of 1.2% as measured by ISO 527; a Tensile Modulus of 20685 MPa as measured by ISO 527; a Flexural Strength of 193 MPa as measured by ISO 178; and a Flexural Modulus of 12411 MPa as measured by ISO 178.

Also an option is a polysulfone (PSU) formulation which is 40% Carbon Fiber Filled and available commercially from RTP Company under the trade name RTP 987. This material has a Tensile Strength of 155 MPa as measured by ISO 527; a Tensile Elongation of 1% as measured by ISO 527; a Tensile Modulus of 24132 MPa as measured by ISO 527; a Flexural Strength of 241 MPa as measured by ISO 178; and a Flexural Modulus of 19306 MPa as measured by ISO 178.

The foregoing materials are well-suited for composite, polymer and insert components of the embodiments disclosed herein, as distinguished from components which preferably are made of metal or metal alloys.

Additional details regarding providing composite soles and/or crowns and crown layups are provided in U.S. patent application Ser. No. 14/789,838, the entire disclosure of which is hereby incorporated by reference.

As described in detail in U.S. Pat. No. 6,623,378, filed Jun. 11, 2001, entitled “METHOD FOR MANUFACTURING AND GOLF CLUB HEAD” and incorporated by reference herein in its entirety, the crown or outer shell of the golf club head10may be made of a composite material, such as, for example, a carbon fiber reinforced epoxy, carbon fiber reinforced polymer, or a polymer. Additionally, U.S. patent application Ser. Nos. 10/316,453 and 10/634,023, also incorporated by reference herein in their entirety, describe golf club heads with lightweight crowns. Furthermore, U.S. patent application Ser. No. 12/974,437 (now U.S. Pat. No. 8,608,591), also incorporated by reference herein in its entirety, describes golf club heads with lightweight crowns and soles.

In some embodiments, composite materials used to construct the crown and/or should exhibit high strength and rigidity over a broad temperature range as well as good wear and abrasion behavior and be resistant to stress cracking. Such properties include (1) a Tensile Strength at room temperature of from about 7 ksi to about 330 ksi, preferably of from about 8 ksi to about 305 ksi, more preferably of from about 200 ksi to about 300 ksi, even more preferably of from about 250 ksi to about 300 ksi (as measured by ASTM D 638 and/or ASTM D 3039); (2) a Tensile Modulus at room temperature of from about 0.4 Msi to about 23 Msi, preferably of from about 0.46 Msi to about 21 Msi, more preferably of from about 0.46 Msi to about 19 Msi (as measured by ASTM D 638 and/or ASTM D 3039); (3) a Flexural Strength at room temperature of from about 13 ksi to about 300 ksi, from about 14 ksi to about 290 ksi, more preferably of from about 50 ksi to about 285 ksi, even more preferably of from about 100 ksi to about 280 ksi (as measured by ASTM D 790); and (4) a Flexural Modulus at room temperature of from about 0.4 Msi to about 21 Msi, from about 0.5 Msi to about 20 Msi, more preferably of from about 10 Msi to about 19 Msi (as measured by ASTM D 790).

In certain embodiments, composite materials that are useful for making club-head components comprise a fiber portion and a resin portion. In general the resin portion serves as a “matrix” in which the fibers are embedded in a defined manner. In a composite for club-heads, the fiber portion is configured as multiple fibrous layers or plies that are impregnated with the resin component. The fibers in each layer have a respective orientation, which is typically different from one layer to the next and precisely controlled. The usual number of layers for a striking face is substantial, e.g., forty or more. However for a sole or crown, the number of layers can be substantially decreased to, e.g., three or more, four or more, five or more, six or more, examples of which will be provided below. During fabrication of the composite material, the layers (each comprising respectively oriented fibers impregnated in uncured or partially cured resin; each such layer being called a “prepreg” layer) are placed superposedly in a “lay-up” manner. After forming the prepreg lay-up, the resin is cured to a rigid condition. If interested a specific strength may be calculated by dividing the tensile strength by the density of the material. This is also known as the strength-to-weight ratio or strength/weight ratio.

In tests involving certain club-head configurations, composite portions formed of prepreg plies having a relatively low fiber areal weight (FAW) have been found to provide superior attributes in several areas, such as impact resistance, durability, and overall club performance. FAW is the weight of the fiber portion of a given quantity of prepreg, in units of g/m2. Crown and/or sole panels may be formed of plies of composite material having a fiber areal weight of between 20 g/m2and 200 g/m2and a density between about 1 g/cc and 2 g/cc. However, FAW values below 100 g/m2, and more desirably 75 g/m2or less, can be particularly effective. A particularly suitable fibrous material for use in making prepreg plies is carbon fiber, as noted. More than one fibrous material can be used. In other embodiments, however, prepreg plies having FAW values below 70 g/m2and above 100 g/m2may be used. Generally, cost is the primary prohibitive factor in prepreg plies having FAW values below 70 g/m2.

In particular embodiments, multiple low-FAW prepreg plies can be stacked and still have a relatively uniform distribution of fiber across the thickness of the stacked plies. In contrast, at comparable resin-content (R/C, in units of percent) levels, stacked plies of prepreg materials having a higher FAW tend to have more significant resin-rich regions, particularly at the interfaces of adjacent plies, than stacked plies of low-FAW materials. Resin-rich regions tend to reduce the efficacy of the fiber reinforcement, particularly since the force resulting from golf-ball impact is generally transverse to the orientation of the fibers of the fiber reinforcement. The prepreg plies used to form the panels desirably comprise carbon fibers impregnated with a suitable resin, such as epoxy. An example carbon fiber is “34-700” carbon fiber (available from Grafil, Sacramento, Calif.), having a tensile modulus of 234 Gpa (34 Msi) and a tensile strength of 4500 Mpa (650 Ksi). Another Grafil fiber that can be used is “TR50S” carbon fiber, which has a tensile modulus of 240 Gpa (35 Msi) and a tensile strength of 4900 Mpa (710 ksi). Suitable epoxy resins are types “301” and “350” (available from Newport Adhesives and Composites, Irvine, Calif.). An exemplary resin content (R/C) is between 33% and 40%, preferably between 35% and 40%, more preferably between 36% and 38%.

Some of the embodiments of the golf club head10discussed throughout this application may include a separate crown, sole, and/or face that may be a composite, such as, for example, a carbon fiber reinforced epoxy, carbon fiber reinforced polymer, or a polymer crown, sole, and/or face. Alternatively, the crown, sole, and/or face may be made from a less dense material, such as, for example, Titanium or Aluminum. A portion of the crown may be cast from either steel (˜7.8-8.05 g/cm3) or titanium (˜4.43 g/cm3) while a majority of the crown may be made from a less dense material, such as for example, a material having a density of about 1.5 g/cm3or some other material having a density less than about 4.43 g/cm3. In other words, the crown could be some other metal or a composite. Additionally or alternatively, the face may be welded in place rather than cast as part of the sole.

By making the crown, sole, and/or face out of a less dense material, it may allow for weight to be redistributed from the crown, sole, and/or face to other areas of the club head, such as, for example, low and forward and/or low and back. Both low and forward and low and back may be possible for club heads incorporating a front to back sliding weight track.

U.S. Pat. No. 8,163,119 discloses composite articles and methods for making composite articles, which disclosure is incorporated by reference herein in the entirety. U.S. Pat. Pub. Nos. 2015/0038262 and 2016/0001146 disclose various composite crown constructions that may be used for golf club heads, which disclosures are also incorporated by reference herein in their entireties. The techniques and layups described in U.S. Pat. No. 8,163,119, U.S. Pat. Pub. No. 2015/0038262 and U.S. Pat. Pub. No. 2016/0001146, incorporated herein by reference in their entirety, may be employed for constructing a composite crown panel, composite sole panel, composite toe panel located on the sole, and/or composite heel panel located on the sole.

U.S. Pat. No. 8,163,119 discloses the usual number of layers for a striking plate is substantial, e.g., fifty or more. However, improvements have been made in the art such that the layers may be decreased to between 30 and 50 layers. Additionally, for a panel located on the sole and/or crown the layers can be substantially decreased down to three, four, five, six, seven, or more layers.

Table 1 below provides examples of possible layups. These layups show possible crown and/or sole construction using unidirectional plies unless noted as woven plies. The construction shown is for a quasi-isotropic layup. A single layer ply has a thickness ranging from about 0.065 mm to about 0.080 mm for a standard FAW of 70 g/m2with about 36% to about 40% resin content, however the crown and/or sole panels may be formed of plies of composite material having a fiber areal weight of between 20 g/m2and 200 g/m2. The thickness of each individual ply may be altered by adjusting either the FAW or the resin content, and therefore the thickness of the entire layup may be altered by adjusting these parameters.

The Area Weight (AW) is calculated by multiplying the density times the thickness. For the plies shown above made from composite material the density is about 1.5 g/cm3 and for titanium the density is about 4.5 g/cm3. Depending on the material used and the number of plies the composite crown and/or sole thickness ranges from about 0.195 mm to about 0.9 mm, preferably from about 0.25 mm to about 0.75 mm, more preferably from about 0.3 mm to about 0.65 mm, even more preferably from about 0.36 mm to about 0.56 mm. It should be understood that although these ranges are given for both the crown and sole together it does not necessarily mean the crown and sole will have the same thickness or be made from the same materials. In certain embodiments, the sole may be made from either a titanium alloy or a steel alloy. Similarly the main body of the golf club head 10 may be made from either a titanium alloy or a steel alloy. The titanium will typically range from 0.4 mm to about 0.9 mm, preferably from 0.4 mm to about 0.8 mm, more preferably from 0.4 mm to about 0.7 mm, even more preferably from 0.45 mm to about 0.6 mm. In some instances, the crown and/or sole may have non-uniform thickness, such as, for example varying the thickness between about 0.45 mm and about 0.55 mm.

A lot of discretionary mass may be freed up by using composite material in the crown and/or sole especially when combined with thin walled titanium construction (0.4 mm to 0.9 mm) in other parts of the golf club head10. The thin walled titanium construction increases the manufacturing difficulty and ultimately fewer parts are cast at a time. In the past, 100+ golf club heads could be cast at a single time, however due to the thinner wall construction fewer golf club heads are cast per cluster to achieve the desired combination of high yield and low material usage.

An important strategy for obtaining more discretionary mass is to reduce the wall thickness of the golf club head10. For a typical titanium-alloy “metal-wood” club-head having a volume of 460 cm3 (i.e., a driver) and a crown area of 100 cm2, the thickness of the crown is typically about 0.8 mm, and the mass of the crown is about 36 g. Thus, reducing the wall thickness by 0.2 mm (e.g., from 1 mm to 0.8 mm) can yield a discretionary mass “savings” of 9.0 g.

The following examples will help to illustrate the possible discretionary mass “savings” by making a composite crown rather than a titanium-alloy crown. For example, reducing the material thickness to about 0.73 mm yields an additional discretionary mass “savings” of about 25.0 g over a 0.8 mm titanium-alloy crown. For example, reducing the material thickness to about 0.73 mm yields an additional discretionary mass “savings” of about 25 g over a 0.8 mm titanium-alloy crown or 34 g over a 1.0 mm titanium-alloy crown. Additionally, a 0.6 mm composite crown yields an additional discretionary mass “savings” of about 27 g over a 0.8 mm titanium-alloy crown. Moreover, a 0.4 mm composite crown yields an additional discretionary mass “savings” of about 30 g over a 0.8 mm titanium-alloy crown. The crown can be made even thinner yet to achieve even greater weight savings, for example, about 0.32 mm thick, about 0.26 mm thick, about 0.195 mm thick. However, the crown thickness must be balanced with the overall durability of the crown during normal use and misuse. For example, an unprotected crown i.e. one without a head cover could potentially be damaged from colliding with other woods or irons in a golf bag.

For example, any of the embodiments disclosed herein may have a crown or sole insert formed of plies of composite material having a fiber areal weight of between 20 g/m2and 200 g/m2, preferably between 50 g/m2and 100 g/m2, the weight of the composite crown being at least 20% less than the weight of a similar sized piece formed of the metal of the body. The composite crown may be formed of at least four plies of uni-tape standard modulus graphite, the plies of uni-tape oriented at any combination of 0° (forward to rearward of the club head), +45°, −45° and 90° (heelward to toeward of the golf club head). Additionally or alternatively, the crown may include an outermost layer of a woven graphite cloth. Carbon crown panels or inserts or carbon sole panels as disclosed herein and in the incorporated applications may be utilized with any of the embodiments herein, and may have a thickness between 0.40 mm to 1.0 mm, preferably 0.40 mm to 0.80 mm, more preferably 0.40 mm to 0.65 mm, and a density between 1 gram per cubic centimeter and 2 gram per cubic centimeter, though other thicknesses and densities are also possible.

One potential embodiment of a carbon sole panel that may be utilized with any of the embodiments herein weighs between 1.0 grams and 5.0 grams, such as between 1.25 grams and 2.75 grams, such as between 3.0 grams and 4.5 grams. In other embodiments, the carbon sole panel may weigh less than 3.0 grams, such as less than 2.5 grams, such as less than 2.0 grams, such as less than 1.75 grams. The carbon sole panel may have a surface area of at least 1250 mm2, 1500 mm2, 1750 mm2, or 2000 mm2.

One potential embodiment of a carbon crown panel that may be utilized with any of the embodiments herein weighs between 3.0 grams and 8.0 grams, such as between 3.5 grams and 7.0 grams, such as between 3.5 grams and 7.0 grams. In other embodiments, the carbon crown panel may weigh less than 7.0 grams, such as less than 6.5 grams, such as less than 6.0 grams, such as less than 5.5 grams, such as less than 5.0 grams, such as less than 4.5 grams. The carbon crown panel may have a surface area of at least 3000 mm2, 3500 mm2, 3750 mm2, 4000 mm2.

FIG. 4illustrates one embodiment of a COR feature. Similar features are shown in the other embodiments. While the illustrated embodiments may only have a COR feature, some embodiments, as in the incorporated applications, may include a COR feature and a sliding weight track, and/or a COR feature, a sliding weight track, and an adjustable lodensift/lie feature or some other combination.

As already discussed, and making reference to the embodiment illustrated inFIG. 4, the COR feature may have a certain length L (which may be measured as the distance between toeward end40and heelward end38of the front channel36), width W (e.g., the measurement from a forward edge to a rearward edge of the front channel36), and offset distance OS from the face20(e.g., the distance between the face20and the forward edge front channel36, also shown inFIG. 7Bas the width of the front ground contact surface54between the face plate34and the front channel36). During development, it was discovered that the COR feature length L and the offset distance OS from the face play an important role in managing the stress which impacts durability, the sound or first mode frequency of the club head, and the COR value of the club head. All of these parameters play an important role in the overall club head performance and user perception.

The offset distance is highly dependent on the slot length. As slot length increases so do the stresses in the club head, as a result the offset distance must be increased to manage stress. Additionally, as slot length increases the first mode frequency is negatively impacted.

During development it was discovered that a ratio of COR feature length to the offset distance may be preferably greater than 4, and even more preferably greater than 5, and most preferably greater than 5.5. However, the ratio of COR feature length to offset distance also has an upper limit and is preferably less than 15, and even more preferably less than 14, and most preferably less than 13.5. For example, for a COR feature length of 30 mm the offset distance from the face would preferably be less than 7.5 mm, and even more preferably 6 mm or less from the face. However, the COR feature can be too close to the face in which the case the club head will fail due to high stresses and/or may have an unacceptably low first mode frequency. The tables below provide various non-limiting examples of COR feature length, offset distance from the face, and ratios of COR feature length to the offset distance.

As can be seen from the tables above, for a COR feature length between 30-60 mm the offset distance is preferably 4 mm or greater and 15 mm or less, more preferably 5 mm or greater and 10 mm or less, most preferably 5.5 mm or greater and 8.5 mm or less. Additionally or alternatively, for a COR feature length between 30-60 mm a ratio of COR feature length to offset distance from the face may be preferably at least 4 and at most 15, more preferably at least 5 and at most 12.5, most preferably at least 6 and at most 12.

As can be seen from the tables above, for a COR feature length between 60-90 mm the offset distance is preferably 4 mm or greater and 15 mm or less, more preferably 5 mm or greater and 13.5 mm or less, most preferably 5.5 mm or greater and 12.5 mm or less. Additionally or alternatively, for a COR feature length between 60-90 mm a ratio of COR feature length to offset distance from the face may be preferably at least 4 and at most 15, more preferably at least 5 and at most 12.5, most preferably at least 6 and at most 12.

Importantly, as COR feature length increases it is important to increase the offset distance from the face. A COR feature length of 60 mm is in between a small COR feature and a large COR feature, which is why it was included in both of the non-limiting examples of above. The ratio is important to maintain and although not all lengths of COR features are provided in the tables above a preferred offset distance range may be calculated by applying the ratio to a given COR feature length.

The sound and feel of golf club heads are vitally important to their acceptance among golfers and especially top golfers. Sound and feel is largely dictated by the club heads first mode frequency, and preferably the club head has a first mode frequency of at least 2800 Hz, such as at least 3000 Hz, such as at least 3200 Hz, such as at least 3400 Hz, such as at least 3500 Hz.

The inventors discovered during the design stage that the COR feature length greatly affects the first mode frequency. The data table and chart inFIGS. 32 and 33, respectively, show the first mode frequency in Hz as a function of slot or COR feature length in mm. Two different designs are shown, a V5 and V6 K-N. Both designs are representative of the embodiments disclosed herein. As illustrated by the slope of the plots illustrated inFIG. 33, for the V5 version each millimeter increase of slot length caused the first mode frequency to decreases by about 45 Hz. Similarly, for the V6 version each millimeter increase of slot length caused the first mode frequency to decreases by about 65 Hz. This information helps determine the overall slot length. Of course, the distance from the face to the slot or COR feature also plays a role in the first mode frequency. For this study the slot offset distance from the face was held constant and only slot length was varied.

In another study, the COR feature offset distance from the face was varied and the COR was measured. A COR feature length of 40 mm was used for the study, and the results will vary depending on the COR feature length. A shorter COR feature length will decrease COR while a longer COR feature length will increase COR. In other words, a shorter COR feature length needs to be closer to the face to achieve the same COR benefits as longer COR feature length. As can be seen from the data COR increases as the COR feature approaches the face. For this particular slot length of 40 mm there is almost no COR benefit beyond 12 mm from the face.

COR feature offset distance from facein mmCOR6.650.81611.650.80015.150.793

The stress levels in a golf club play an important role in determining its durability. The COR feature tends to decrease stress in the face, but can enhance stress in other areas more proximate to the COR feature itself. For low face stress near the COR feature it was discovered that the COR feature offset distance drives low face stress. The inventors conducted a stress study using a COR feature length of about 70 mm. The inventors investigated increasing the sole and wall thickness by 0.3 mm to reduce low face stress by 200 MPa, however this caused the COR to decrease by 0.005 points. Next, the inventors investigated decreasing the COR feature length by 30 mm to about 40 mm to reduce low face stress by 200 MPa, however this caused the COR to decrease by 0.012 points. Finally, the inventors investigated increasing the COR feature offset distance from the face by 1 mm to reduce low face stress by 200 MPa, and this only caused the COR to decrease by 0.001 points. Accordingly, the COR feature offset distance from the face plays the biggest role in stress management and in effecting the overall COR of the club head.

FIGS. 11-18illustrate another exemplary golf club head100that is similar to golf club head10, and which embodies additional inventive technologies disclosed herein. The golf club head100comprises a body102(shown isolated inFIGS. 11, 13, and 15-18), a hosel106comprising a hosel bore108, in which a golf club shaft may be inserted and secured to the golf club head100, and a crown insert140that is attached to the body102. The golf club head100defines a front end or face112, rear end128, toe side116, heel side118, lower side or sole120, and upper side or crown138. The front end112includes a face plate114, which may be an integral part of the body102or a separate insert. Though not shown, the front end112can include a face opening to receive a face plate114that is attached to the body by welding, braising, soldering, screws or other fastening means. A skirt portion136extends around the periphery of the club head between the sole120and crown138and excluding the face plate114. Near the face plate114, a front channel122is formed in the sole120. As illustrated inFIG. 16, the channel122extends into an interior cavity104of the golf club head100, and so, as illustrated inFIG. 12, may be provided with a slot insert158to prevent dirt, grass, or other elements from entering the interior of the body102. The front channel122extends in the toe-heel directions across the sole, with a heelward end124near the hosel106and an opposite toeward end126.

As best illustrated inFIG. 13, a forward mass pad130is separated from and positioned rearward of the front channel122, and a second, rearward mass pad132is positioned near a rear sole surface156and formed integrally with the rear end128of the golf club head100. Exemplary embodiments of the structure of the forward mass pad130are further described herein. In the illustrated embodiment, the rearward mass pad132is shown as being formed on the heel side118of the golf club head100, though in other embodiments, it might be situated closer to the center of the rear end128of the golf club head100, or even on the toe side116, of the golf club head100.

The body102can include a front ground contact surface148forward of the front channel122adjacent the bottom of the face plate114. The body can also have an intermediate ground contact surface, or sit pad,150rearward of the front channel122. The intermediate ground contact surface150can have an elevation and curvature congruent with that of the front ground contact surface148. The body102can further comprise a downwardly extending rear sole surface156that extends around the perimeter of the rear end128. In some embodiments, the rear sole surface156can act as a ground contact or sit pad as well, having a curvature and elevation congruent with that of the front ground contact surface148and the intermediate ground contact surface150.

The body102can further include a raised sole portion152that is recessed up from the intermediate ground contact surface150and from the rear sole surface156. The raised sole portion152can span over any portion of the sole120, and in the illustrated embodiment the raised sole portion152spans over most of the rearward portion of the sole. The sole120can include one or more sloped transition portions154, including where the intermediate ground contact surface150transitions up to the raised sole portion152. The sole can also include other similar sloped portions (not shown), such as around the boundary of the raised sole portion152. In some embodiments, as illustrated, one or more cantilevered ribs or struts164can be included on the sole that span from the sloped transition portion154to the raised sole portion152, to provide increased stiffness and rigidity to the sole.

The raised sole portion152can optionally include grooves, channels, ridges, or other surface features that increase its rigidity, such as ridges166and grooves168, best illustrated inFIG. 16. Similarly, the intermediate ground contact surface150can include stiffening surface features, such as ridges166, though grooves or other stiffening features can be substituted for the ridges.

The body102can also include one or more internal ribs, such as rib164inFIGS. 13 and 15, that are integrally formed with or attached to the inner surfaces of the body. Such ribs can vary in size, shape, location, number and stiffness, and can be used strategically to reinforce or stiffen designated areas of the body's interior and/or fine tune acoustic properties of the golf club head.

FIG. 13illustrates a cross-section of the golf club head100ofFIG. 11. In the illustrated embodiment, in addition to the rearward mass pad132described previously, the forward mass pad130further comprises three separate sections, all of which are integrally formed into a single structure. Alternatively, the three sections may be formed separately, but placed in contact, or in close proximity to one another. While three sections are illustrated, it is understood that more or fewer sections may be formed. The first section, heel mass section170, is positioned adjacent the heel side118of the golf club head100, and comprises a first heel mass portion172nearest the heel side118, having a first forward to rearward dimension, and a second heel mass portion174that is further from the heel side118than the first heel mass portion172, and has a second forward to rearward dimension. In the illustrated embodiment, this second forward to rearward dimension is smaller than the first forward to rearward dimension, though these relative dimensions could be reversed. Further, as illustrated inFIG. 17, heel mass section170has a vertical height that may be higher in the first heel mass portion172near the heel side118and may slope downward toward the second heel mass portion174. Additionally, the heel mass section170may have one or more edges that slope downward from a first vertical height to an edge portion that makes contact with the sole120.

Opposite the heel mass section170and adjacent the toe side116of the golf club head100is a second, toe mass section180, which comprises a first toe mass portion182nearest the toe side116, having a third forward to rearward dimension. In the illustrated embodiment this third forward to rearward dimension is shown as similar to the first forward to rearward dimension of the first heel mass portion172, but these first and third forward to rearward dimensions may in some cases be different. The toe mass section180further comprises a second toe mass portion184that is further from the toe side116than the first toe mass portion182, and has a fourth forward to rearward dimension. In the illustrated embodiment, this fourth forward to rearward dimension is smaller than the third forward to rearward dimension, though these relative dimensions could be reversed. In the illustrated embodiment, this fourth forward to rearward dimension is shown as similar to the second forward to rearward dimension of the second heel mass portion174, but these first and third forward to rearward dimensions may in some cases be different. Further, as illustrated inFIG. 17, toe mass section180has a vertical height that may be higher in the first toe mass portion182near the toe side116and may slope downward toward the second toe mass portion182. Additionally, the toe mass section180may have one or more edges that slope downward from a first vertical height to an edge portion that makes contact with the sole120.

Positioned in between the heel mass section170and toe mass section180is a third, middle mass section176, which in the illustrated embodiment has a fifth forward to rearward dimension that is smaller than any of the four forward to rearward dimensions described for the heel mass section170and toe mass section180. However, in other embodiments, the middle mass section176could have a similar dimension to, e.g., the second toe mass portion184and the second heel mass portion174. Also shown in the illustrated embodiment, the smaller forward to rearward dimension of the middle mass section176provides space to position a weight port190between the heel mass section170and the toe mass section180, each of which may be indented slightly to provide room for the weight port190. Additionally, the middle mass section176in the illustrated embodiment has a smaller mass than the heel mass section170and toe mass section180, providing increased perimeter weighting, which can increase the mass moment of inertia of the golf club head, particularly the moments of inertia about the CG z-axis, Izz, and the CG x-axis, Ixx. The mass for the heel mass section170and toe mass section180may be similar, or alternatively, may be weighted differently, depends on the needs of the club designer. Similarly, each of the first heel mass portion172and the first toe mass portion182has a greater mass than their corresponding second heel mass portion174and second toe mass portion184, again moving additional discretionary mass to the perimeter of the club, further increasing the mass moment of inertia of the golf club head, particularly the moments of inertia about the CG z-axis, Izz, and the CG x-axis, Ixx.

As shown inFIGS. 12 and 14, the golf club head100can optionally include a separate crown insert140that is secured to the body102, such as by applying a layer of epoxy adhesive142, or other securement means, such as bolts, rivets, snap fit, other adhesives, or other joining methods or any combination thereof, to cover a large opening144at the top and rear of the body, forming part of the crown138of the golf club head. The crown insert140covers a substantial portion of the crown's surface area as, for example, at least 40%, at least 60%, at least 70% or at least 80% of the crown's surface area. The crown's outer boundary generally terminates where the crown surface undergoes a significant change in radius of curvature, e.g., near where the crown transitions to the golf club head's sole120, hosel106, and front end112.

As illustrated inFIGS. 15-18, the crown opening144can be formed to have a recessed peripheral ledge or seat146to receive the crown insert140, such that the crown insert is either flush with the adjacent surfaces of the body to provide a smooth seamless outer surface or, alternatively, slightly recessed below the body surfaces. The front of the crown insert140can join with a front portion of the crown138on the body to form a continuous, arched crown extend forward to the face. The crown insert140can comprise any suitable material (e.g., lightweight composite and/or polymeric materials) and can be attached to the body in any suitable manner, as described in more detail elsewhere herein.

As illustrated inFIG. 14, the hosel bore108may pass through the hosel and open up into the interior cavity104of the body102. Similar to the hosel inFIG. 8B, hosel106may have a plurality of indentations110around its circumference.

In addition to, or in place of the mass pads described above, certain embodiments disclosed herein, such as those inFIGS. 11-31, can be provided with one or more weight ports formed in the body that are configured to receive one or more removable weights, which can have a mass selected to positively impact various measurements of the golf club head, such as to vary Delta 1 of the golf club head to a value greater than 5 mm, greater than 10 mm, greater than 15 mm, and greater than 18.5 mm, or to further impact other measurements such as MOI, Zup, or the like.

For example, as illustrated inFIG. 11, and as further described above, weight port190is positioned adjacent to and is partially surrounded by forward mass pad130.FIG. 16illustrates a cross-sectional view that shows one example of the weight port190that provides the capability of a removable weight192to be removably engageable with the sole120. The illustrated weight port190defines internal threads196that correspond to external threads formed on a threaded weight portion194of the removable weight190, as well as a larger diameter area to retain the head portion193of the removable weight. The weight port190can have any of a number of various configurations to receive and retain any of a number of weights or weight assemblies, such as described in U.S. Pat. Nos. 6,773,360, 7,166,040, 7,452,285, 7,628,707, 7,186,190, 7,591,738, 7,963,861, 7,621,823, 7,448,963, 7,568,985, 7,578,753, 7,717,804, 7,717,805, 7,530,904, 7,540,811, 7,407,447, 7,632,194, 7,846,041, 7,419,441, 7,713,142, 7,744,484, 7,223,180, 7,410,425 and 7,410,426, the entire contents of each of which are incorporated by reference in their entirety herein.

Additionally, or alternatively, in other embodiments (not shown), weight ports may be positioned in a crown, or skirt of a golf club head.

FIGS. 12 and 13further illustrate the weight port190and a removable weight192that may be inserted therein. Other examples of removable weights engageable with weight ports are shown in, e.g.,FIGS. 19-31, which are described more fully herein. In some embodiments, as in, e.g.,FIG. 11, a single weight port190and removable weight192is provided, while in others, as illustrated in, e.g.,FIG. 19, a plurality of weight ports (e.g., two, three, four, five, six, or more) and engageable weights are provided. Any number of weight ports may be utilized with embodiments of this disclosure, as appropriate to suit the needs of the golf club head designer. Weights and/or weight assemblies configured for weight ports in the sole as described in this disclosure can vary in mass from about 0.5 grams to about 10 grams, from about 0.5 grams to about 20 grams, from about 2 grams to about 18 grams, or from about 2 grams to about 20 grams. Weights having other masses may also be used, if appropriate and/or desired.

Inclusion of one or more weights in the weight port(s) provides a customizable golf club head mass distribution, and corresponding mass moments of inertia and center-of-gravity locations. Adjusting the location of the weight port(s) and the mass of the weights and/or weight assemblies provides various possible locations of center-of-gravity and various possible mass moments of inertia using the same golf club head.

As discussed in more detail below, in some embodiments, a playable fairway wood golf club head can have a low, rearward center-of-gravity. Placing one or more weight ports and weights rearward in the sole as shown, for example, inFIGS. 19-31, helps desirably locate the center-of-gravity. Additionally or alternatively, a number of removable weight ports may be situated adjacent the heel and toe sections of the club, as also illustrated inFIGS. 19-31, and/or additional weight ports may be situated proximal to a front channel, as illustrated inFIGS. 11-31.

In another exemplary embodiment, shown, for example, inFIGS. 19-31, golf club head200comprises a body202defining an internal cavity212, a hosel218comprising a hosel bore220, in which a golf club shaft may be inserted and secured to the golf club head202, as further described below, and a crown insert216that is attached to the body202. The golf club head100defines a front end or face222, rear end224, toe side226, heel side228, lower side or sole208, and upper side or crown230. The front end222includes face plate214, which may be an integral part of the body202or a separate insert. Though not shown, the front end222can include a face opening to receive a face plate214that is attached to the body by welding, braising, soldering, screws or other fastening means. A skirt portion232extends around the periphery of the club head between the sole208and crown230and excluding the face plate214. Near the face plate214, a front channel210is formed in the sole120. As illustrated inFIG. 24, the channel210extends into an interior cavity212of the golf club head100, and so may be provided with a slot insert (not shown) to prevent dirt, grass, or other elements from entering the interior of the body202. The front channel210extends in the toe-heel directions across the sole, with a heelward end234near the hosel218and an opposite toeward end236.

The body202can include a front ground contact surface238forward of the front channel210adjacent the bottom of the face plate214. The body can also have an intermediate ground contact surface, or sit pad,240rearward of the front channel210. The intermediate ground contact surface240can have an elevation and curvature congruent with that of the front ground contact surface238. The body202can further comprise a downwardly extending rear sole surface246that extends around the perimeter of the rear end224. In some embodiments, the rear sole surface246can act as a ground contact or sit pad as well, having a curvature and elevation congruent with that of the front ground contact surface238and the intermediate ground contact surface240.

The body102can further include a raised sole portion242that is recessed up from the intermediate ground contact surface240and from the rear sole surface246. The raised sole portion242can span over any portion of the sole208, and in the illustrated embodiment the raised sole portion242spans over most of the forward portion of the sole. The sole208can include one or more sloped transition portions244, including where the intermediate ground contact surface240transitions up to the raised sole portion242, or as illustrated, where the rear sole surface246transitions up to the raised sole portion242. The sole can also include other similar sloped portions (not shown), such as around the boundary of the raised sole portion242.

In certain embodiments, a center of gravity of at least some of the weights is preferably located rearward of a midline of the golf club head along the y-axis, such as, for example, within about 40 mm of the rear end224of the golf club head, or within about 30 mm of the rear end224of the golf club head, or within about 20 mm of the rear end224of the golf club head.

In the illustrated embodiment, as shown inFIG. 19, additional weight ports, rear toe-side weight port204d,rear center weight port204e,and rear heel-side weight port204fare positioned around the sole208near the perimeter of the skirt232. As illustrated inFIG. 19, the weight ports may be generally trapezoidal, with a broader portion positioned around the skirt232, and extending inward to a narrower portion positioned in the sole208of the golf club head200. Openings250may be included in the weight port in which a removable weight, e.g., removable weights206, may be at least partially retained, such as by connecting the weights to the golf club head200using a threaded opening or other methods, such as those described above with regard to the removable weights installed in weight port190, and in the incorporated references.

As described with reference to rear center weight port204e,and as illustrated inFIGS. 22A and 22B, each of the rear weight ports is configured to at least partially retain a removable weight, which may be similar to removable weight192, or other similar weights described above and in the incorporated applications. Rear center weight port204ecomprises a weight port opening205surrounded by a recessed retaining portion260, which may be utilized to at least partially retain a head portion of a removable weight (not shown), which may be configured and retained similar to removable weights192or206described herein, or other similar weight heads described in the incorporated applications. Weight port opening205is positioned within a first raised surface261of the recessed retaining portion, which is substantially parallel to, and raised up from the sole208of the golf club head200. On a first side of the recessed retaining portion260nearest the skirt232, rear center weight port204ehas a peripheral wall262, which in the illustrated embodiment extends up from the raised surface261and is angled slightly outward toward the skirt232, and in the illustrated embodiment runs parallel to the skirt232, forming the longer base of the weight port's trapezoidal shape. Opposite the peripheral wall262is an internal wall264, forming the top (shorter side) of the trapezoid. The internal wall264extends up from the raised surface261at an obtuse angle towards the sole238of the golf club head in the rear sole surface246. In between the peripheral wall262and the internal wall264are side walls266which also extend up from the raised surface261at opposed obtuse angles, one angling heelward, and the other angling toeward. Optionally, as in the illustrated embodiment, a transition surface268may be positioned between internal wall264and each of the side walls266. The transition surface may form rounded edges for the top of the trapezoid adjacent the top (shorter side) of the trapezoid. Rear toe-side weight port204dand rear heel-side weight port204fmay have a similar structure to rear center weight port204e,and are shown in further detail inFIGS. 26 and 27, respectively.

Golf club head200can have a center-of-gravity that is located to provide a preferable center-of-gravity projection on the face plate214of the golf club head. In those embodiments, as illustrated inFIG. 19, one or more front weight ports (204a,204b,and204C in the illustrated embodiment) and optional removable weights206are placed in the sole208forward of a midline of the golf club head along the y-axis. A front center weight port204ais located between a front toe-side weight port204band a front heel-side weight port204c,and is located adjacent to and rearward of front channel210. As described previously, the weight ports can have any of a number of various configurations to receive and retain any of a number of weights or weight assemblies. In the embodiment shown, three weight ports are located adjacent to and rearward of the front channel.

In an alternative embodiment, raised sole portion242may contain a recess mass body (not shown) that is sized to fit within and substantially fill the footprint of the recess the raised sole portion242forms in the sole208. The recess mass body may have a mass that is between 30 to 80 grams, or in some particular embodiments, a mass that is between 40 and 60 grams. In other embodiments, the recess mass body may have a smaller mass, between 20 and 40 grams. In certain embodiments, this recess mass body may be retained by, e.g., removable weights206, which may be screws or bolts or other suitable fasteners that are inserted through the mass and into the sole208to at least partially retain the recess mass body within the raised sole portion242. In still other embodiments, the recess mass body may be smaller, and may be sized and shaped so as to allow it to be slidably retained within the raised sole portion242. For example, the recess mass body may have an internal slot that runs approximately parallel to the sloped transition portion244to slidably retain a single one of the removable weights206. When tightened, the removable weight206retains the recess mass body in place. When removable weight206is loosened, the recess mass body may slide laterally in a heelward or toeward direction to adjust, for example CGx, such as to control left or right tendency of a golf swing. Additionally, projections (such as parallel ribbed projections) may be provided on the surface of raised sole portion242to interact with corresponding projections on a mating surface of the recess mass body to better hold it the desired position when removable weight206is tightened.

As discussed above, the configuration of the front channel210and its position near the face plate214allows the face plate to undergo more deformation while striking a ball than a comparable golf club head without the front channel210, thereby increasing both COR and the speed of golf balls struck by the golf club head. As a result, the ball speed after impact is greater for the golf club head having the channel210than for a conventional golf club head, which results in a higher COR. The weight ports204a,204b,and204care separated from the front channel210by a distance of approximately 1 mm to about 5 mm, such as about 1.5 mm to about 3 mm. In some embodiments, a center of gravity of one or more removable weights206placed in the sole208of the golf club head is located within about 30 mm of the nearest portion of a forward edge of the sole, such as within about 20 mm of the nearest portion of the forward edge of the sole, or within about 15 mm of the nearest portion of the forward edge of the sole, or within about 10 mm of the nearest portion of the forward edge of the sole. Although other methods (e.g., using internal weights attached using epoxy or hot-melt glue) of adjusting the center-of-gravity can be used, use of a weight port and/or integrally molding a discretionary weight into the body202of the golf club head reduces undesirable effects on the audible tone emitted during impact with a golf ball.

The body202can also include one or more internal ribs, such as ribs270a,270b,and270cinFIG. 23, that are integrally formed with or attached to the inner surfaces of the body. Such ribs can vary in size, shape, location, number and stiffness, and can be used strategically to reinforce or stiffen designated areas of the body's interior and/or fine tune acoustic properties of the golf club head. In the illustrated embodiment, each of ribs270a,270b,and270cextends from one of the front weight ports—204a,204b,and204c,respectively, which are situated adjacent the front channel210—to a corresponding one of the rear weight ports—204e,204d,and204f,respectively, which are situated around the periphery, or skirt232, of the golf club head202.

As shown inFIGS. 20, 21, and 27, the golf club head200can optionally include a separate crown insert216that is secured to the body202, such as by applying a layer of epoxy adhesive or other securement means, such as bolts, rivets, snap fit, other adhesives, or other joining methods or any combination thereof, to cover a large opening (not shown) at the top and rear of the body, forming part of the crown230of the golf club head. The crown insert216covers a substantial portion of the crown's surface area as, for example, at least 40%, at least 60%, at least 70% or at least 80% of the crown's surface area. The crown's outer boundary generally terminates where the crown surface undergoes a significant change in radius of curvature, e.g., near where the crown transitions to the golf club head's sole208, hosel218, and front end222. As described above, and as partially shown inFIGS. 22A and 22B, the crown opening can be formed to have a recessed peripheral ledge or seat252to receive the crown insert216, such that the crown insert is either flush with the adjacent surfaces of the body to provide a smooth seamless outer surface or, alternatively, slightly recessed below the body surfaces. The front of the crown insert216can join with a front portion of the crown230on the body202to form a continuous, arched crown extend forward to the face. The crown insert216can comprise any suitable material, and can be attached to the body in any suitable manner, as described in more detail herein.

The golf club head's hosel218further provides a shaft connection assembly that allows the shaft to be easily disconnected from the golf club head, and that provides the ability for the user to selectively adjust a and/or lie-angle of the golf club. The hosel218defines a hosel bore220, which in turn is adapted to receive a hosel insert280. The hosel bore220is also adapted to receive a shaft sleeve282mounted on the lower end portion of a shaft, as described in U.S. Pat. No. 8,303,431. A recessed port284is provided on the sole208, and extends from the sole208into the interior cavity212of the body202toward the hosel218, and in particular the hosel bore220. The hosel bore220extends from the hosel218through the golf club head and opens within the recessed port284at the sole208of the golf club head200.

The golf club head is removably attached to the shaft by shaft sleeve282(which is mounted to the lower end portion of a golf club shaft300) by inserting the shaft sleeve282into the hosel bore220and a hosel insert280(which is mounted inside the hosel bore220), and inserting a screw290(or other suitable fixation device) upwardly through the recessed port284and through an opening in the sole and, in the illustrated embodiment, tightening the screw290into a threaded opening of the shaft sleeve282, thereby securing the golf club head to the shaft sleeve282. A screw capturing device, such as in the form of an o-ring or washer292, can be placed on the shaft of the screw290to retain the screw in place within the golf club head when the screw is loosened to permit removal of the shaft from the golf club head.

The recessed port284extends from the bottom portion of the golf club head into the interior of the outer shell toward the top portion of the golf club head200at the location of hosel218, as seen inFIGS. 28-30. In the embodiment shown, the mouth of the recessed port290in the sole208is generally oval-shaped, although the shape and size of the recessed port290may be different in alternative embodiments.

The shaft sleeve282has a lower portion286including splines that mate with mating splines of the hosel insert282, an intermediate portion288and an upper head portion294. The intermediate portion288and the head portion294define an internal bore296for receiving the tip end portion of the shaft300. In the illustrated embodiment, the intermediate portion288of the shaft sleeve has a cylindrical external surface that is concentric with the inner cylindrical surface of the hosel bore220. As described in more detail in U.S. Patent Application Publication No. 2010/0197424, which is hereby incorporated by reference, inserting the shaft sleeve282at different angular positions relative to the hosel insert280is effective to adjust the shaft loft and/or the lie angle. For example, the loft angle may be increased or decreased by various degrees, depending on the angular position, such as +/−1.5 degrees, +/−2.0 degrees, or +/−2.5 degrees. Other loft angle adjustments are also possible.

In the embodiment shown, because the intermediate portion288is concentric with the hosel bore220, the outer surface of the intermediate portion288can contact the adjacent surface of the hosel bore220, as depicted inFIG. 30. This allows easier alignment of the mating features of the assembly during installation of the shaft and further improves the manufacturing process and efficiency.

In certain embodiments, the golf club head may be attached to the shaft via a removable head-shaft connection assembly as described in more detail in U.S. Pat. No. 8,303,431, the entire contents of which are incorporated by reference herein in their entirety. Further in certain embodiments, the golf club head may also incorporate features that provide the golf club heads and/or golf clubs with the ability not only to replaceably connect the shaft to the head but also to adjust the loft and/or the lie angle of the club by employing a removable head-shaft connection assembly. Such an adjustable lie/loft connection assembly is described in more detail in U.S. Pat. No. 8,025,587, U.S. Pat. No. 8,235,831, U.S. Pat. No. 8,337,319, as well as U.S. Publication No. 2011/0312437A1, U.S. Publication No. 2012/0258818A1, U.S. Publication No. 2012/0122601A1, U.S. Publication No. 2012/0071264A1 as well as U.S. patent application Ser. No. 13/686,677, filed on Nov. 27, 2012, the entire contents of which patent, publications and application are incorporated in their entirety by reference herein.

In view of the many possible embodiments to which the principles of the disclosed technology may be applied, it should be recognized that the illustrated embodiments are only preferred examples and should not be taken as limiting the scope of the disclosed technology. Rather, the scope of the disclosure is intended to be at least as broad as the scope of the following claims. We therefore claim as our invention all that comes within the scope and spirit of these claims.