EP2419183A1

EP2419183A1 - Golf club head or other ball striking device having face insert

Info

Publication number: EP2419183A1
Application number: EP10714772A
Authority: EP
Inventors: John Thomas Stites; Jr. George W. Moody
Original assignee: Nike International Ltd
Current assignee: Nike Innovate CV USA
Priority date: 2009-04-15
Filing date: 2010-04-13
Publication date: 2012-02-22
Also published as: JP2012527252A; WO2010120728A1; CN102395408A; US20100267467A1

Abstract

A ball striking device (100), such as a golf club, includes a head (102) with a face (112) having an outer surface configured for striking a ball, a body (108) connected to the face, and an insert (140) connected to the face and forming a portion of the outer surface. The density and/or friction properties of the insert may be different from those of adjacent portions of the face. Depending on the size, shape, and location of the insert, the moment of inertia of the head may change, the center of gravity of the face may shift, and/or the degree and direction of spin on the ball resulting from impacts may change.

Description

GOLF CLUB HEAD OR OTHER BALL STRIKING DEVICE HAVING FACE INSERT

TECHNICAL FIELD

[0001] The invention relates generally to ball striking devices, such as golf club heads, having at least one face insert. Certain aspects of this invention relate to golf club heads having an insert made from a material having desired properties, forming at least a portion of the ball striking face of the head.

BACKGROUND

[0002] Golf is enjoyed by a wide variety of players - players of different genders, and players of dramatically different ages and skill levels. Golf is somewhat unique in the sporting world in that such diverse collections of players can play together in golf outings or events, even in direct competition with one another (e.g., using handicapped scoring, different tee boxes, etc.), and still enjoy the golf outing or competition. These factors, together with increased golf programming on television (e.g., golf tournaments, golf news, golf history, and/or other golf programming) and the rise of well known golf superstars, at least in part, have increased golfs popularity in recent years, both in the United States and across the world.

[0003] Golfers at all skill levels seek to improve their performance, lower their golf scores, and reach that next performance "level." Manufacturers of all types of golf equipment have responded to these demands, and recent years have seen dramatic changes and improvements in golf equipment. For example, a wide range of different golf ball models now are available, with some balls designed to fly farther and straighter, provide higher or flatter trajectory, provide more spin, control, and feel (particularly around the greens), etc.

[0004] Being the sole instrument that sets a golf ball in motion during play, the golf club also has been the subject of much technological research and advancement in recent years. For example, the market has seen improvements in golf club heads, shafts, and grips in recent years. Additionally, other technological advancements have been made in an effort to better match the various elements of the golf club and characteristics of a golf ball to a particular user's swing features or characteristics (e.g., club fitting technology, ball launch angle measurement technology, etc.).

[0005] Despite the various technological improvements, golf remains a difficult game to play at a high level. For a golf ball to reliably fly straight and in the desired direction, a golf club must meet the golf ball square (or substantially square) to the desired target path. Moreover, the golf club must meet the golf ball at or close to a desired location on the club head face (i.e., on or near a "desired" or "optimal" ball contact location) to reliably fly straight, in the desired direction, and for a desired distance. Off-center hits may tend to "twist" the club face when it contacts the ball, thereby sending the ball in the wrong direction, imparting undesired hook or slice spin, and/or robbing the shot of distance. Club face/ball contact that deviates from squared contact and/or is located away from the club's desired ball contact location, even by a relatively minor amount, also can launch the golf ball in the wrong direction, often with undesired hook or slice spin, and/or can rob the shot of distance. Accordingly, club head features that can help a user keep the club face square with the ball would tend to help the ball fly straighter and truer, in the desired direction, and often with improved and/or reliable distance.

[0006] Golf clubs must make square contact with the golf ball, in the desired direction or path, in order to produce straight and true shots in the desired direction. Even small deviations from squareness between the club head and the golf ball at the point of contact can cause inaccuracy. Various golf club heads have been designed to improve a golfer's accuracy by assisting the golfer in squaring the club head face at impact with a golf ball. A number of golf club heads reposition the weight of the golf club head in order to alter the location of the club head's center of gravity. The location of the center of gravity of the golf club head is one factor that determines whether a golf ball is propelled in the intended direction. When the center of gravity is positioned behind the point of engagement on the contact surface, the golf ball follows a generally straight route. When the center of gravity is spaced to a side of the point of engagement, however, the golf ball may fly in an unintended direction and/or may follow a route that curves left or right, ball flights that are often referred to as "pulls," "pushes," "draws," "fades," "hooks," or "slices". Similarly, when the center of gravity is spaced above or below the point of engagement, the route of the golf ball may exhibit more boring or climbing trajectories, respectively. [0007] The degree of twisting of the club head upon off-center impacts can also be dependent upon the moment of inertia of the club head. Generally, a higher moment of inertia results in less twisting of the club head on impact. The moment of inertia can be increased by distributing the weight of the club head proportionally more toward the edges of the head and away from the center.

[0008] Many off-center golf hits are caused by common errors in swinging the golf club that are committed repeatedly by the golfer, and which may be similarly committed by many other golfers. As a result, patterns can often be detected, where a large percentage of off-center hits occur in certain areas of the club face. For example, one such pattern that has been detected is that many high handicap golfers tend to hit the ball on the low-heel area of the club face and/or on the high-toe area of the club face. Other golfers may tend to miss in other areas of the club face. Because golf clubs are typically designed to contact the ball at or around the center of the face, such off-center hits may result in less energy being transferred to the ball, decreasing the distance of the shot. The energy or velocity transferred to the ball by a golf club also may be related, at least in part, to the flexibility of the club face at the point of contact, and can be expressed using a measurement called "coefficient of restitution" (or "COR"). The maximum COR for golf club heads is currently limited by the USGA at 0.83. Also, as described above, the direction of ball flight and the degree of twisting of the club head during impact may also be related, at least in part, to the moment of inertia of the club head and the location of the center of gravity of the club head with relation to the point of impact. The energy or velocity transferred to the ball by the golf club may also be related to the moment of inertia and/or the location of the center of gravity of the club head. Accordingly, a need exists to customize or adjust the moment of inertia and/or the location of the center of gravity of a golf club face to provide maximum energy transfer and minimum twisting for impacts in the areas of the face where off-center hits tend to occur most.

[0009] The distance and direction of ball flight can also be significantly affected by the spin imparted to the ball by the impact with the club head. While the ball is in the air, aerodynamic forces caused by the speed and direction of ball spin can cause the trajectory of the ball to be higher or lower, or to curve, and create "pulls," "pushes," "draws," "fades," "hooks," "slices," etc. Additionally, the spin of the ball can change the behavior of the ball as it rolls and bounces after impact with the ground. For example, a high degree of backspin can cause the ball to slow, stop, or even roll backward upon impact, and conversely, topspin or lesser degrees of backspin will cause the ball to travel a greater distance after impact with the ground. Various speeds and directions of spin on the ball can be a product of many factors, including the point of impact, the direction of the club head upon impact, the degree of twisting of the club head upon impact, and the location of the center of gravity of the club head. The coefficient of friction of the club face at the point of impact can also have a significant influence on the degree of spin imparted to the ball upon impact. Accordingly, a need exists to customize or adjust the moment of inertia, the location of the center of gravity, and/or the coefficient of friction of a golf club face to achieve a desired speed and direction of spin on a ball for impacts in the areas of the face where off-center hits tend to occur most.

[0010] The present device and method are provided to address the problems discussed above and other problems, and to provide advantages and aspects not provided by prior ball striking devices of this type. A full discussion of the features and advantages of the present invention is deferred to the following detailed description, which proceeds with reference to the accompanying drawings.

BRIEF SUMMARY

[0011] The following presents a general summary of aspects of the invention in order to provide a basic understanding of the invention. This summary is not an extensive overview of the invention. It is not intended to identify key or critical elements of the invention or to delineate the scope of the invention. The following summary merely presents some concepts of the invention in a general form as a prelude to the more detailed description provided below.

[0012] Aspects of the invention relate to ball striking devices, such as golf clubs, with a head that includes a face configured for striking a ball and a body connected to the face, the body being adapted for connection of a shaft thereto. Various example structures of heads described herein include an insert connected to the face and forming a portion of the outer surface. The density and/or friction properties of the insert are different from those of the portion of the face adjacent or bordering the insert. The shape of the insert can be designed to increase the moment of inertia and/or shift the center of gravity of the face, as well as to provide different spin on the ball, based on locations on the face where a golfer tends to hit the ball. Consequently, the golf shot may experience increased "kick" off the face and straighter ball flight on off-center hits (provided the off-center hits impact the face at the locations of increased flexibility and at a sufficient velocity), e.g., due to decreased twisting of the face during impacts at these locations. Additionally, the flight and travel of the ball may be altered due to the different spin imparted by the insert.

[0013] According to one aspect, the insert is positioned asymmetrically to the geometric center of the face. In one embodiment, where the insert has a lower density than the face material, the face has a center of gravity that is positioned away from the geometric center of the face as a result of the lower density of the insert.

[0014] According to another aspect, where the insert has a lower density than the face material, the center of gravity of the insert is located away from the geometric center of the face, and the center of gravity of the face is located away from the center of gravity of the insert. In one embodiment, the center of gravity of the insert is located in one direction from the geometric center of the face, and the center of gravity of the face is located in an opposite direction from the geometric center of the face.

[0015] According to another aspect, the face includes four quadrants extending from the geometric center of the face, and at least one quadrant contains a greater proportion of the insert, compared to at least one other quadrant. In one embodiment, where the insert has a lower density than the face material, each quadrant has a weight distribution that is inversely related to the proportion of the insert located in the respective quadrant. In another embodiment, where the insert has a lower friction property than the outer surface of the face, the average degree of spin imparted to the ball from impacts in each quadrant of the face is inversely related to the proportion of the insert located in the respective quadrant.

[0016] According to another aspect, where the insert has a lower friction property than the outer surface of the face, the insert occupies an area of the outer surface, and ball impacts on the area of the outer surface occupied by the insert impart less spin to the ball compared to impacts on other areas of the outer surface. In one embodiment, the impacts on the insert impart less backspin to the ball than impacts on other areas of the outer surface. [0017] According to another aspect, the insert is received in a cavity extending inwardly from the outer surface of the face.

[0018] According to a further aspect, both the density and the friction properties of the insert are lower than those of the face.

[0019] Additional aspects of the invention relate to a golf club head that includes a face having a ball striking surface configured for striking a ball, and a body connected to the face. The face includes a first material having a first density and a first friction property and a second material having a second density and a second friction property. The second density is lower than the first density and the second friction property is lower than the first friction property. Each of the first material and the second material form a portion of the ball striking surface.

[0020] According to one aspect, the second material is embodied in an insert that is connected to the face to form a portion of the outer surface of the face, as described above. Aspects of the insert discussed above can be equally applicable to the second material.

[0021] Other aspects of this invention relate to face members for use in a ball striking device, including a face, a wall extending rearward from an outer periphery of the face, and an insert connected to the face to form a portion of the outer surface of the face, as described above. The outer surface of the face is configured for striking a ball, and an inner surface is located rearward and opposite of the outer surface.

[0022] Further aspects of the invention relate to methods that can be used for manufacturing or customizing a golf club head, which is provided with a face configured for striking a ball with an outer surface thereof and a body connected to the face. The method includes connecting an insert to the face, where the insert has a lower density and/or a lower friction property than the adjacent or bordering areas of the face. The method may also include removing the insert and interchanging it with another insert having at least one different property.

[0023] Still further aspects of the invention relate to a kit that includes a golf club head as described above and at least one insert configured for connection to the face of the ball striking head. The insert(s) have a lower density and/or a lower friction property than the adjacent or bordering areas of the face. The kit may include a plurality of inserts having different properties, and the inserts may be interchangeable with each other.

[0024] Still further aspects of the invention relate to golf clubs that include a golf club head as described above and a shaft connected to the head.

[0025] Other features and advantages of the invention will be apparent from the following description taken in conjunction with the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] To allow for a more full understanding of the present invention, it will now be described by way of example, with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of an illustrative embodiment of a head of a ball striking device according to the present invention, shown with a ball;

FIG. 2 is a front view of the head of FIG. 1, illustrating an insert in the face of the head;

FIG. 3 is a cross-section view of the head of FIG. 1, taken along lines 3-3 of FIG. 1 ;

FIG. 4 is a perspective view of a second illustrative embodiment of a ball striking device according to the present invention;

FIG. 5 is a front view of a head of the ball striking device of FIG. 3, illustrating an insert in the face of the head;

FIG. 6 is a cross-section view of the head of FIG. 4, taken along lines 6-6 of FIG. 5;

FIG. 7 is a front view of a third illustrative embodiment of a head of a ball striking device according to the present invention, illustrating an insert in the face of the head;

FIG. 8 is a front view of a fourth illustrative embodiment of a head of a ball striking device according to the present invention, illustrating an insert in the face of the head;

FIG. 9 is a front view of a fifth illustrative embodiment of a head of a ball striking device according to the present invention, illustrating an insert in the face of the head;

FIG. 10 is a front view of a sixth illustrative embodiment of a head of a ball striking device according to the present invention, illustrating an insert in the face of the head;

FIG. 11 is a front view of a seventh illustrative embodiment of a head of a ball striking device according to the present invention, illustrating an insert in the face of the head; FIG. 12 is a front view of an eighth illustrative embodiment of a head of a ball striking device according to the present invention, illustrating an insert in the face of the head;

FIG. 13 is a front view of a ninth illustrative embodiment of a head of a ball striking device according to the present invention, illustrating an insert in the face of the head;

FIG. 14 is a front view of a tenth illustrative embodiment of a head of a ball striking device according to the present invention, illustrating an insert in the face of the head;

FIG. 15 is a front view of an eleventh illustrative embodiment of a head of a ball striking device according to the present invention, illustrating an insert in the face of the head;

FIG. 16 is a cross-section view of one illustrative embodiment of a face having an insert and being suitable for use with a head of a ball striking device according to the present invention;

FIG. 17 is a cross-section view of a second illustrative embodiment of a face having an insert and being suitable for use with a head of a ball striking device according to the present invention;

FIG. 18 is a cross-section view of a third illustrative embodiment of a face having an insert and being suitable for use with a head of a ball striking device according to the present invention; and

FIG. 19 is a cross-section view of a fourth illustrative embodiment of a face having an insert and being suitable for use with a head of a ball striking device according to the present invention.

DETAILED DESCRIPTION

[0027] In the following description of various example structures according to the invention, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration various example devices, systems, and environments in which aspects of the invention may be practiced. It is to be understood that other specific arrangements of parts, example devices, systems, and environments may be utilized and structural and functional modifications may be made without departing from the scope of the present invention. Also, while the terms "top," "bottom," "front," "back," "side," "rear," and the like may be used in this specification to describe various example features and elements of the invention, these terms are used herein as a matter of convenience, e.g., based on the example orientations shown in the figures or the orientation during typical use. Additionally, the term "plurality," as used herein, indicates any number greater than one, either disjunctively or conjunctively, as necessary, up to an infinite number. Nothing in this specification should be construed as requiring a specific three dimensional orientation of structures in order to fall within the scope of this invention. Also, the reader is advised that the attached drawings are not necessarily drawn to scale.

[0028] The following terms are used in this specification, and unless otherwise noted or clear from the context, these terms have the meanings provided below.

[0029] "Ball striking device" means any device constructed and designed to strike a ball or other similar objects (such as a hockey puck). In addition to generically encompassing "ball striking heads," which are described in more detail below, examples of "ball striking devices" include, but are not limited to: golf clubs, putters, croquet mallets, polo mallets, baseball or softball bats, cricket bats, tennis rackets, badminton rackets, field hockey sticks, ice hockey sticks, and the like.

[0030] "Ball striking head" means the portion of a "ball striking device" that includes and is located immediately adjacent (optionally surrounding) the portion of the ball striking device designed to contact the ball (or other object) in use. In some examples, such as many golf clubs and putters, the ball striking head may be a separate and independent entity from any shaft or handle member, and it may be attached to the shaft or handle in some manner.

[0031] The terms "shaft" and "handle" are used synonymously and interchangeably in this specification, and they include the portion of a ball striking device (if any) that the user holds during a swing of a ball striking device.

[0032] "Integral joining technique" means a technique for joining two pieces so that the two pieces effectively become a single, integral piece, including, but not limited to, irreversible joining techniques, such as adhesively joining, cementing, welding, brazing, soldering, or the like, where separation of the joined pieces cannot be accomplished without structural damage thereto.

[0033] "Friction property/properties" means the degree of friction and/or traction that a material exhibits relative to other materials, including both static friction and kinetic friction, and can be determined with reference to the coefficient of friction (μ) of the material in contact with the outer surface of a golf ball, in the solid state and at ambient conditions. The compressed ball total contact surface area during impact may be referenced in some embodiments for calculating friction properties, as the total friction between two surfaces may depend on the total area of contact between them. Applicable ASTM standard surface tests can be used to calculate these properties, including standards such as ASTM G-115 and/or ASTM G- 194.

[0034] In general, aspects of this invention relate to ball striking devices, such as golf club heads, golf clubs, putter heads, putters, and the like. Such ball striking devices, according to at least some examples of the invention, may include a ball striking head and a ball striking surface. In the case of a golf club, the ball striking surface is a substantially flat surface on one face of the ball striking head. Some more specific aspects of this invention relate to wood-type golf clubs and golf club heads, including drivers, fairway woods, wood-type hybrid clubs, and the like, although aspects of this invention also may be practiced on irons, iron-type hybrid clubs, and the like.

[0035] According to various aspects of this invention, the ball striking device may be formed of one or more of a variety of materials, such as metals (including metal alloys), ceramics, polymers, composites (including fiber-reinforced composites), and wood, and may be formed in one of a variety of configurations, without departing from the scope of the invention. In one illustrative embodiment, some or all components of the head, including the face and at least a portion of the body of the head, are made of metal. It is understood that the head may contain components made of several different materials, including carbon-fiber and other components. Additionally, the components may be formed by various forming methods. For example, metal components (such as titanium, aluminum, titanium alloys, aluminum alloys, steels (including stainless steels), and the like) may be formed by forging, molding, casting, stamping, machining, and/or other known techniques. In another example, composite components, such as carbon fiber-polymer composites, can be manufactured by a variety of composite processing techniques, such as prepreg processing, powder-based techniques, mold infiltration, and/or other known techniques.

[0036] The various figures in this application illustrate examples of ball striking devices according to this invention. When the same reference number appears in more than one drawing, that reference number is used consistently in this specification and the drawings refer to the same or similar parts throughout.

[0037] At least some examples of ball striking devices according to this invention relate to golf club head structures, including heads for wood-type golf clubs, such as drivers, as well as long iron clubs (e.g., driving irons, zero irons through five irons, and hybrid type golf clubs), short iron clubs (e.g., six irons through pitching wedges, as well as sand wedges, lob wedges, gap wedges, and/or other wedges), and putters. Such devices may include a one-piece construction or a multiple-piece construction. Example structures of ball striking devices according to this invention will be described in detail below in conjunction with FIG. 1, which illustrates an example of a ball striking device 100 in the form of a golf driver, and FIG. 4, which illustrates an example of a ball striking device 200 in the form of an iron-type golf club, in accordance with at least some examples of this invention.

[0038] FIGS. 1-3 illustrate a ball striking device 100 in the form of a golf driver, in accordance with at least some examples of this invention. As shown in FIG. 1, the ball striking device 100 includes a ball striking head 102 and a shaft 104 connected to the ball striking head 102 and extending therefrom. A ball 106 in use is also schematically shown in FIG. 1, in a position to be struck by the ball striking device 100. The ball striking head 102 of the ball striking device 100 of FIG. 1 has a face 112 connected to a body 108, with a hosel 109 extending therefrom. Any desired hosel and/or head/shaft interconnection structure may be used without departing from this invention, including conventional hosel and/or head/shaft interconnection structures as are known and used in the art. For reference, the head 102 generally has a top 116, a bottom or sole 118, a heel 120 proximate the hosel 109, a toe 122 distal from the hosel 109, a front 124, and a back or rear 126. The shape and design of the head 102 may be partially dictated by the intended use of the device 100. In the club 100 shown in FIG. 1, the head 102 has a relatively large volume, as the club 100 is designed for use as a driver or wood-type club, intended to hit the ball accurately over long distances. In other applications, such as for a different type of golf club, the head may be designed to have different dimensions and configurations. When configured as a driver, the club head may have a volume of at least 400 cc, and in some structures, at least 450 cc, or even at least 460 cc. Other appropriate sizes for other club heads may be readily determined by those skilled in the art. [0039] In the illustrative embodiment illustrated in FIGS. 1-3, the head 102 has a hollow structure defining an inner cavity (e.g., defined by the face 112 and the body 108). Thus, the head 102 has a plurality of inner surfaces defined therein. In one embodiment, the hollow center cavity may be filled with air. However, in other embodiments, the head 102 could be filled with another material, such as foam. In still further embodiments, the solid materials of the head may occupy a greater proportion of the volume, and the head may have a smaller cavity or no inner cavity at all. It is understood that the inner cavity may not be completely enclosed in some embodiments.

[0040] The face 112 is located at the front 124 of the head 102, and has a ball striking surface 110 located thereon and an inner surface 111 opposite the ball striking surface 110. The ball striking surface 110 is typically an outer surface of the face 112 configured to face a ball 106 in use, and is adapted to strike the ball 106 when the device 100 is set in motion, such as by swinging. As shown, the ball striking surface 110 is relatively flat, occupying most of the face 112. For reference purposes, the portion of the face 112 nearest the top face edge 113 and the heel 120 of the head 102 is referred to as the "high-heel area" 160; the portion of the face 112 nearest the top face edge 113 and toe 122 of the head 102 is referred to as the "high-toe area" 162; the portion of the face 112 nearest the bottom face edge 115 and heel 120 of the head 102 is referred to as the "low-heel area" 164; and the portion of the face 112 nearest the bottom face edge 115 and toe 122 of the head 102 is referred to as the "low-toe area" 166. Conceptually, these areas 160-166 may be recognized and referred to as quadrants of substantially equal size (and/or quadrants extending from a geometric center of the face 112), though not necessarily with symmetrical dimensions. The face 112 may include some curvature in the top to bottom and/or heel to toe directions (e.g., bulge and roll characteristics), as is known and is conventional in the art. In other embodiments, the surface 110 may occupy a different proportion of the face 112, or the body 108 may have multiple ball striking surfaces 110 thereon. In the illustrative embodiment shown in FIG. 1, the ball striking surface 110 is inclined slightly (i.e., at a loft angle), to give the ball 106 slight lift and spin when struck. In other illustrative embodiments, the ball striking surface 110 may have a different incline or loft angle, to affect the trajectory of the ball 106. Additionally, the face 112 may have a variable thickness and/or may have one or more internal or external inserts in some embodiments. [0041] It is understood that the face 112, the body 108, and/or the hosel 109 can be formed as a single piece or as separate pieces that are joined together. In the illustrative embodiment shown in FIG. 3, the face 112 is formed as part of a face frame member 128, with a wall or walls 125 extending rearward from the edges 127 of the face 112. This configuration is also known as a cup face structure. The body 108 can be formed as a separate piece or pieces joined to the walls 125 of the face frame member 128. In the illustrative embodiment shown in FIG. 3, the body 108 is partially formed by a backbody member 129, which may be a single piece or multiple pieces. The walls 125 of the face frame member 128 combine with the backbody member 129 to form the body 108 of the head 102. These pieces may be connected by an integral joining technique, such as welding, cementing, or adhesively joining. Other known techniques for joining these parts can be used as well, including many mechanical joining techniques, including releasable mechanical engagement techniques. If desired, the hosel 109 may be integrally formed as part of the face frame member 128. Further, a gasket (not shown) may be included between the face frame member 128 and the backbody member 129.

[0042] FIGS. 4-6 illustrate a ball striking device 200 in the form of a golf iron, in accordance with at least some examples of this invention. Many common components between the ball striking device 100 of FIGS. 1-3 and the ball striking device 200 of FIGS. 4-6 are referred to using similar reference numerals in the description that follows, using the "200" series of reference numerals. The ball striking device 200 includes a shaft 204 and a golf club head 202 attached to the shaft 204. The golf club head 202 of FIG. 4 may be representative of any iron or hybrid type golf club head in accordance with examples of the present invention.

[0043] As shown in FIGS. 5-6, the golf club head 202 includes a body member 208 having a face 212 and a hosel 209 extending from the body 208 for attachment of the shaft 204. For reference, the head 202 generally has a top 216, a bottom or sole 218, a heel 220 proximate the hosel 209, a toe 222 distal from the hosel 209, a front 224, and a back or rear 226. The shape and design of the head 202 may be partially dictated by the intended use of the device 200. The heel portion 220 is attached to and/or extends from a hosel 209 (e.g., as a unitary or integral one piece construction, as separate connected elements, etc.). [0044] The face 212 is located at the front 224 of the head 202, and has a ball striking surface 210 located thereon and an inner surface 211 opposite the ball striking surface 210. The ball striking surface 210 is typically an outer surface of the face 212 configured to face a ball (not shown) in use, and is adapted to strike the ball when the device 200 is set in motion, such as by swinging. As shown, the ball striking surface 210 is relatively flat, occupying most of the face 212. The ball striking surface 210 may include grooves 152 (e.g., generally horizontal grooves 152 extending across the face 212 in the illustrated example) for the removal of water and grass from the face 212 during a ball strike. Of course, any number of grooves, desired groove patterns, and/or groove constructions may be provided (or even no groove pattern, if desired), including conventional groove patterns and/or constructions, without departing from this invention.

[0045] For reference purposes, the portion of the face 212 nearest the top face edge 213 and the heel 220 of the head 202 is referred to as the "high-heel area" 260; the portion of the face 212 nearest the top face edge 213 and toe 222 of the head 202 is referred to as the "high-toe area" 262; the portion of the face 212 nearest the bottom face edge 215 and heel 220 of the head 202 is referred to as the "low-heel area" 264; and the portion of the face 212 nearest the bottom face edge 215 and toe 222 of the head 202 is referred to as the "low-toe area" 266. Conceptually, these areas 260-266 may be recognized and referred to as quadrants of substantially equal size (and/or quadrants extending from a geometric center of the face 212), though not necessarily with symmetrical dimensions. The face 212 may include some curvature in the top to bottom and/or heel to toe directions (e.g., bulge and roll characteristics), as is known and is conventional in the art. In other embodiments, the surface 210 may occupy a different proportion of the face 212, or the body 208 may have multiple ball striking surfaces 210 thereon. In the illustrative embodiment shown in FIG. 5, the ball striking surface 210 is inclined (i.e., at a loft angle), to give the ball an appreciable degree of lift and spin when struck. In other illustrative embodiments, the ball striking surface 210 may have a different incline or loft angle, to affect the trajectory of the ball. Additionally, the face 212 may have a variable thickness and/or may have one or more internal or external inserts in some embodiments. It is understood that the face 212, the body 208, and/or the hosel 209 can be formed as a single piece or as separate pieces that are joined together. [0046] The body member 208 of the golf club head 202 may be constructed from a wide variety of different materials, including materials conventionally known and used in the art, such as steel, titanium, aluminum, tungsten, graphite, polymers, or composites, or combinations thereof. Also, if desired, the club head 202 may be made from any number of pieces (e.g., having a separate face plate, etc.) and/or by any construction technique, including, for example, casting, forging, welding, and/or other methods known and used in the art.

[0047] The ball striking device 100, 200 may include a shaft 104, 204 connected to or otherwise engaged with the ball striking head 102, 202, as shown schematically in FIGS. 1 and 4. The shaft 104, 204 is adapted to be gripped by a user to swing the ball striking device 100, 200 to strike the ball 106. The shaft 104, 204 can be formed as a separate piece connected to the head 102, 202, such as by connecting to the hosel 109, 209, as shown in FIGS. 1 and 4. In other illustrative embodiments, at least a portion of the shaft 104, 204 may be an integral piece with the head 102, 202, and/or the head 102, 202 may not contain a hosel 109, 209 or may contain an internal hosel structure. Still further embodiments are contemplated without departing from the scope of the invention. The shaft 104, 204 may be constructed from one or more of a variety of materials, including metals, ceramics, polymers, composites, or wood. In some illustrative embodiments, the shaft 104, 204, or at least portions thereof, may be constructed of a metal, such as stainless steel or titanium, or a composite, such as a carbon/graphite fiber-polymer composite. However, it is contemplated that the shaft 104, 204 may be constructed of different materials without departing from the scope of the invention, including conventional materials that are known and used in the art. A grip element 205 may be positioned on the shaft 104, 204 to provide a golfer with a slip resistant surface with which to grasp golf club shaft 104, 204, as shown in FIG. 4. The grip element 205 may be attached to the shaft 104, 204 in any desired manner, including in conventional manners known and used in the art (e.g., via adhesives or cements, threads or other mechanical connectors, swedging/swaging, etc.).

[0048] In general, the head 102, 202 of the ball striking device 100, 200 has a face 112, 212 with at least one insert 140 connected thereto. The embodiment of the head 102 illustrated in FIGS. 2-3 and the embodiment of the head 202 illustrated in FIGS. 5-6 both contain a single insert 140 that is received in a cavity 114 in the face 112, 212, and forms a portion of the outer surface 110, 210 of the face 112, 212. It is understood that in other embodiments, the face 112, 212 may have any number of inserts, and may include any number of cavities 114 to receive such inserts.

[0049] The head 102 shown in FIGS. 2-3 and the head 202 shown in FIGS. 5-6 are shown with substantially the same insert 140 contained in the faces 112, 212 thereof. The inserts 140 are substantially triangular in shape, and more specifically, have a substantially equilateral triangular shape. Each face 112, 212 has a cavity 114 that is complementarily shaped with the insert 140 to receive the insert therein. In other embodiments, cavities 114 and inserts 140 described herein may have any desired shape, although generally the cavities 114 may be shaped and otherwise configured to receive the appropriate insert 140 in a complementary manner, as in the examples shown in FIGS. 2-3 and 5-6.

[0050] The cavity 114 and the insert 140 may extend partially or completely through the face 112, 212. In one embodiment, the insert 140 extends to the outer surface 110, 210 of the face 112, 212 and forms a portion of the outer surface 110, 210, and in another embodiment, the insert 140 extends to the inner surface 11 1, 21 1 of the face 1 12, 212. In the embodiments shown in FIGS. 2-3, 5-6, 16, and 18-19, the inserts 140, 140J, 140L, 140M extend completely through the face 112, 212. In the embodiment shown in FIG. 17, described below, the insert 140K extends only a portion of the way through the face 112. In all the embodiments illustrated herein, the insert 140, 140 J-M extends to the outer surface 110, 210 of the face 112, 212, forms a part of the outer surface 110, and is flush with the outer surface 110, 210. It is understood that in other embodiments, the insert may not extend to the outer surface 110, 210 or may not be flush with the outer surface 110, 210. Additionally, as illustrated in FIG. 5, the inserts 140 may have grooves 150 thereon that are cooperatively positioned to match with the grooves 152 on the outer surface 210 of the face 212.

[0051] Each insert 140 may be made of one or more different materials, and the properties of each insert 140 can influence the properties of the face 112, 212. In one embodiment, the insert 140 can be made from a material that is different from the material from which the face 112, 212 is made. The use of an insert 140 made from a different material and having different properties can allow for customization of the face 112, 212 to achieve specified performance characteristics. [0052] One such property is the density of the material of the insert 140. It is understood that the density of the material can be influenced by the natural density properties of the bulk insert material, as well as other factors, such as the porosity of the material. In one embodiment, the insert 140 has a density that is different from the density of the material of the face 112, 212. By using an insert 140 having a different density than the face 112, 212, the weight distribution, center of gravity, and moment of inertia of the head 102, 202 and face 112, 212 can be adjusted. For example, by connecting an insert 140 having a low density nearest or at the center of the face 112, 212, the weight of the face 112, 212 can be distributed toward the edges of the face 112, 212, increasing the moment of inertia of the face 112, 212 and the head 102, 202. Conversely, the use of a heavier insert 140 can distribute the weight more toward the center of the face 112, 212. Additionally, an insert 140 having a different density than the face material can be used to shift the center of gravity of the face 112, 212 toward a desired area of the face 112, 212, such as an area where missed hits frequently occur. It is understood that the density of the insert 140 may be different relative to the density of a bulk or majority of the face 112, 212 or relative to the density of a portion of the face 112, 212 bordering or adjacent to the insert 140, and that some portions of the face 112, 212 may have the same or a similar density as the insert 140.

[0053] The size, shape, location, and density of the insert 140, as well as other factors, may affect how the center of gravity of the face 112, 212 is shifted by connecting the insert 140 to the face. When an insert 140 having a low density is used, the weight distribution of the face 112, 212 is generally shifted away from the areas of the face 112, 212 where the insert 140 is located. Likewise, a low density insert 140 can be used to shift the center of gravity away from the area where the insert 140 is located, such as by using an insert that is asymmetrical with respect to the geometric center of the face 112, 212. For example, when a low-density insert 140 is predominately located toward the heel 120 of the face 140, the weight of the face is distributed more toward the toe 122, and the center of gravity is also shifted toward the toe 122. As another example, when a low-density insert 140 is predominately located toward the top edge 113 of the face 112, 212, the weight of the face 112, 212 is distributed more toward the bottom edge 115, and the center of gravity is also shifted lower on the face 112, 212. Viewed another way, when a low-density insert 140 occupies an area of the face 112, 212, the weight of the face 112, 212 is disproportionately distributed toward areas of the face 112, 212 not occupied by the insert 140. For example, in one embodiment, at least one quadrant of the face 1 12, 212 contains a greater proportion of the insert 140, compared to at least one other quadrant, and each quadrant has a relative weight distribution that is inversely related to the proportion of the insert 140 located in the respective quadrant. Conversely, when a high-density insert 140 is connected to the face 112, 212, it may have opposite effects to those described above for a low-density insert.

[0054] Accordingly, as illustrated in FIGS. 2, 5, and 7-15, when the center of gravity 170 of a low density insert 140, 140A-I is located away from a geometric center 172 of the face 112, 212, the center of gravity 174 of the face 112, 212 may be shifted away from the center of gravity 170 of the insert 140, 140A-I. In the embodiments illustrated in FIGS. 2, 5, 7, and 9-14, the inserts 140, 140A, and 140C-H are asymmetrical with respect to the geometric center 172 of the face 112, 212. Consequently, the center of gravity 170 of each of these low density inserts 140, 140A, and 140C-H is located in one direction from the geometric center 172 of the face 112, 212, and the center of gravity 174 of the face 112, 212 is located in substantially the opposite direction from the geometric center 172 of the face 112, 212. For example, in the embodiments illustrated in FIGS. 2 and 5, the center of gravity 170 of the insert 140 is located upwardly from the geometric center 172 of the face 112, 212, and the center of gravity 174 of the face 112, 212 is shifted downwardly from the geometric center 172 of the face 112, 212. Additionally, the weight of the face 112, 212 is disproportionately distributed toward the low heel area 164 and the low toe area 166 of the face 112, 212. The change in weight distributions and shift (if any) of the center of gravity 174 of the face 112, 212 caused by the various inserts 140A-I illustrated in FIGS. 7-16 are described below. It is understood that the use of additional inserts and/or variations in thickness of the face 112, 212 can also affect shifting of weight distribution and/or the center of gravity.

[0055] The friction properties of the outer surface of the insert are another property of the insert 140 that can allow customization of the properties of the face 112, 212. It is understood that the friction properties of the insert can be influenced by the natural frictional properties of the bulk material (such as coefficient of friction), as well as other factors, such as the smoothness or texture of the surface of the material. Additionally, the material may have a coating on the outer surface that can change the friction properties of the outer surface of the insert 140. In one embodiment, the insert 140 has friction properties that are different from the friction properties of the material of the face 112, 212. By using an insert 140 having different friction properties than the face 112, 212, the degree of spin imparted to the ball by impacts to specific areas of the face 112, 212 can be adjusted. For example, an insert 140 having a low friction surface may impart less spin to the ball during impacts on the area of the face 112, 212 occupied by the insert 140, and conversely, an insert 140 having a high friction surface may impart greater spin to the ball. In one embodiment, an insert 140 having a low friction surface is connected to the face 112, 212 to decrease the backspin imparted to the ball upon impact, increasing the average distance traveled by the ball. Viewed another way, when a low-friction insert 140 occupies an area of the face 112, 212, the average degree of spin imparted to the ball by impacts in that area is decreased. For example, in one embodiment, at least one quadrant of the face 112, 212 contains a greater proportion of the insert 140, compared to at least one other quadrant, and the average degree of spin imparted to a ball from impacts in each quadrant is inversely related to the proportion of the insert 140 located in the respective quadrant. It is understood that the friction property of the insert 140 may be different relative to the friction property of a bulk or maj ority of the face 112, 212 or relative to the friction property of a portion of the face 112, 212 bordering or adjacent to the insert 140, and that some portions of the face 112, 212 may have the same or a similar friction property as the insert 140.

[0056] In the embodiments illustrated in FIGS. 2 and 5, the insert 140 has a lower friction surface than the other areas of the face 112, 212. Accordingly, center hits and off-center hits toward the high center, the low center, and toward the high heel area 160 and the high toe area 162 will experience decreased spin due to the lower degree of friction of the insert material. The change in the degree of spin imparted to the ball by impacts in specific areas of the face 112, 212 resulting from use of the various inserts 140 A-I illustrated in FIGS. 7-16 are described below.

[0057] The material of the insert can be selected based on density, friction properties, and/or any other property, and may be a metal (including metal alloys), a ceramic, a polymer, a composite (including fiber-reinforced composites), wood, or any other suitable material. In one embodiment, where the club head is a wood-type club head, such as the head 102 shown in FIGS. 1-3, the insert 140 is made from a polyolefin material, which has a low density and low friction properties. In another embodiment, where the club head is an iron-type club head, such as the head 202 shown in FIGS. 4-6, the insert 140 is made from a titanium-aluminum alloy, which has a low density and low friction properties. Any other material having desired density and physical properties and high lubricity can be used in various other embodiments.

[0058] FIGS. 7-15 show various different shapes for inserts 140 A-I that may be used in connection with the head 102, and it is understood that the face 112 may contain one or more cavities 114 that are shaped to receive each insert 140A-I. It is understood that each of these inserts 140 A-I is shown in a particular orientation, but that the orientation of the inserts 140 A-I may be changed, such as by rotating the insert to be oriented in a vertical, horizontal, or oblique manner. Some of the inserts 140A-I shown in FIGS. 7-15 are positioned asymmetrically with respect to the geometric center 172 of the face 112, such as the inserts 140A and 140C-H shown in FIGS. 7 and 9-14. The inserts 140A-I are illustrated as part of a face 112 as shown in FIGS. 1-3, but in other embodiments, faces (such as the face 212 in FIGS. 4-6) may be constructed with inserts having these and other shapes, in order to enable different weighting and frictional properties, as described above. The effects each of these inserts 140 A-I can have on the weighting and frictional properties of the face 112 are described below, as if the insert 140A-I was connected to the face 112 in the locations and orientations shown. It is understood that changing the orientation and/or location of each insert 140 A-I may change these effects. Additionally, for purposes of the discussion below, these inserts 140A-I are assumed to have low densities and low friction surfaces. It is further understood that changing these and other properties may also change the effects the inserts 140A-I can have on the weighting, frictional properties, and/or other properties of the face 112.

[0059] FIG. 7 illustrates an insert 140A having a triangular shape similar to the insert 140 of FIGS. 2-3 and 5-6, rotated 180° in orientation. When this insert 140A is placed in the location and orientation shown, the moment of inertia of the face 112 will be increased, the weight will be proportionally distributed toward the high heel area 160 and the high toe area 162, and the center of gravity 174 will be shifted upward on the face 112. Additionally, center hits and off-center hits toward the high center, the low center, and toward the low-heel area 164 and the low-toe area 166 will experience decreased spin due to the lower degree of friction of the insert material. It is understood that rotating the orientation of the insert 140A by 180° will cause a top-to- bottom reverse of these properties, such that the properties would be similar to those described above for the insert 140 shown in FIGS. 2-3 and 5-6. [0060] FIG. 8 illustrates an insert 140B having a substantially circular shape. When this insert 140B is placed in the location and orientation shown, the moment of inertia of the face 112 will be increased, the weight will be proportionally distributed toward both the heel 120 and toe 122, and the center of gravity 174 will not be substantially affected. Additionally, center hits and off-center hits in a radius around the center of the face 1 12 will experience decreased spin due to the lower degree of friction of the insert material.

[0061] FIG. 9 illustrates an insert 140C having a substantially right-triangular shape. When this insert 140C is placed in the location and orientation shown, the moment of inertia of the face 112 will be increased, the weight will be proportionally distributed toward the low heel area 164, and the center of gravity 174 will be shifted toward the low heel area 164. Additionally, center hits and off-center hits high on the face 112 and toward the high heel area 160, the high toe area 162, and the low toe area 166 will experience decreased spin due to the lower degree of friction of the insert material. It is understood that this insert 140C can be oriented and located on the face 112 to shift the center of gravity toward the high toe area 162, such as by rotating the orientation of the insert 140C by 180°.

[0062] FIG. 10 illustrates an insert 140D having a substantially right-triangular shape. When this insert 140D is placed in the location and orientation shown, the moment of inertia of the face 112 will be increased, the weight will be proportionally distributed toward the high heel area 160, and the center of gravity 174 will be shifted toward the high heel area 160. Additionally, center hits and off-center hits low on the face 112 and toward the high toe area 162, the low heel area 164, and the low toe area 166 will experience decreased spin due to the lower degree of friction of the insert material. It is understood that this insert 140D can be oriented and located on the face 112 to shift the center of gravity toward the low toe area 166, such as by rotating the orientation of the insert 140D by 180°.

[0063] FIG. 11 illustrates an insert 140E having a substantially isosceles triangular shape, oriented horizontally. When this insert 140E is placed in the location and orientation shown, the moment of inertia of the face 112 will be increased, the weight will be proportionally distributed toward the high heel area 160 and low heel area 164, and the center of gravity 174 will be shifted toward the heel 120. Additionally, center hits and off-center hits toward the toe 122 will experience decreased spin due to the lower degree of friction of the insert material. It is understood that these properties may be laterally reversed (e.g., the center of gravity shifted toward the toe 122) by using the insert 140E in a 180° rotated orientation.

[0064] FIG. 12 illustrates an insert 140F having a substantially asymmetrical trapezoidal shape. When this insert 140F is placed in the location and orientation shown, the moment of inertia of the face 112 will be increased, the weight will be proportionally distributed toward the low heel area 164, and the center of gravity 174 will be shifted toward the low heel area 164. Additionally, center hits and off-center hits toward the high heel area 160 and toward the toe 122 will experience decreased spin due to the lower degree of friction of the insert material. It is understood that the insert 140F can be used to shift the center of gravity 174 toward the high heel area 160, the high toe area 162, or the low toe area 166, such as by flipping and/or rotating the insert 140F as appropriate.

[0065] FIG. 13 illustrates an insert 140G having a substantially symmetrical trapezoidal shape. When this insert 140G is placed in the location and orientation shown, the moment of inertia of the face 112 will be increased, the weight will be proportionally distributed toward the low heel area 164 and the low toe area 166, and the center of gravity 174 will be shifted downward on the face 112. Additionally, center hits and off-center hits toward the low center of the face and the entire top of the face 112 will experience decreased spin due to the lower degree of friction of the insert material. It is understood that rotating the orientation of the insert 140G by 180° will cause a top-to-bottom reverse of these properties (e.g., the weight will be distributed toward the high heel 160 and high toe 162).

[0066] FIG. 14 illustrates an insert 140H having a substantial T-shape. When this insert 140H is placed in the location and orientation shown, the moment of inertia of the face 112 will be increased, the weight will be proportionally distributed toward the low heel area 164 and the low toe area 166, and the center of gravity 174 will be shifted downward on the face 112. Additionally, center hits and off-center hits toward the entire top of the face 112 will experience decreased spin due to the lower degree of friction of the insert material. It is understood that rotating the orientation of the insert 1401 by 180° will cause a top-to-bottom reverse of these properties (e.g., the weight will be distributed toward the high heel 160 and high toe 162). [0067] FIG. 15 illustrates an insert 1401 having a substantially rectangular shape. When this insert 1401 is placed in the location and orientation shown, the moment of inertia of the face 112 will be increased, the weight will be proportionally distributed toward the heel 120 and the toe 122, and the center of gravity 174 will not be substantially shifted. Additionally, center hits and off-center hits toward the high center and low center of the face 112 will experience decreased spin due to the lower degree of friction of the insert material. It is understood that different properties can be achieved by using the insert 1401 in different rotated orientations.

[0068] In further embodiments, inserts may be used having additional properties to allow customization of other properties of the face 112, 212 as desired. Additionally, the face 112, 212 can be configured to use inserts of nearly any shape and size in order to customize the properties of the face 112, 212.

[0069] The insert 140 can be connected within the cavity 114 in any manner, including any and all connecting techniques known to those skilled in the art, which may depend on the shape and configuration of the cavity 114 and/or insert 140. In one example, shown in FIGS. 3 and 6, the insert 140 is connected within the cavity 114 using an integral joining technique, such as cementing or adhesively joining. Other joining techniques can be used in other embodiments, and several configurations using such techniques are described below and illustrated in FIGS. 16-19.

[0070] In another example, as shown in FIG. 16, the insert 140J includes an extension 144 that is received in a notch 142 on the inside of the cavity 114, allowing the insert 140J to be connected to the face 112. The face 1 12 and the insert 140J may include additional notches 142 and extensions 144, and the notch(es) 142 and extension(s) 144 may extend partially or entirely around the periphery of the cavity 114 and the insert 140J.

[0071] In another example, as shown in FIG.17, the cavity 114 does not extend completely through the face 112, and the insert 140K is connected in the cavity 114 using one or more connectors 143 inserted from the inner surface 11 1, such as screws. It is understood that the face 112 may include one or more passageways (not shown) to allow insertion of the connectors 143 therethrough, and that the connectors 143 and the passageways may be complementarily threaded for threadable engagement. Additionally, the inner surface 111 of the face 112 may include countersunk portions (not shown) to receive portions of the connectors 143, such as the head of a screw, bolt, nail, rivet, etc.

[0072] In a further example, shown in FIG. 18, the insert 140L is connected in the cavity 114 using an integral joining technique, but may also be connected by another technique, such as a friction or interference fit. Additionally, in the embodiment shown in FIG. 18, the face 112 includes supports 146 on the inner surface 111 designed to prevent the insert 140L from being pushed inward on impacts with the ball, and these supports 146 may extend partially or entirely around the cavity 114.

[0073] In yet another example, shown in FIG. 19, the insert 140M includes a notch 148 that receives an extension 149 on the inside of the cavity 114, allowing the insert 140M to be connected to the face 112. The insert 140M and the face 112 may include additional notches 148 and extensions 149, and the notch(es) 148 and extension(s) 149 may extend partially or entirely around the periphery of the insert 140J and the cavity 114.

[0074] Further connecting techniques known in the art may be used to connect the inserts 140 within the cavities 114, such as clamping, magnetic force, additional types of mechanical connectors, swedging/swaging (including hydraulic swedging), etc. It is understood that any of the insert configurations described herein can be connected to the face 112 using the connection techniques described herein.

[0075] FIGS. 16-19, described above, show a general cross-section of a face 112 for a ball striking device, having an outer (ball striking) surface 1 10 and an opposed inner surface 111. It is understood that while the reference numerals "112," "110," and "111" are used to describe the features of FIGS. 16-19, the features of the faces 112 shown in FIGS. 16-19 can be incorporated into the head 102 of the ball striking device 100 of FIGS. 1-3 and the head 202 of the ball striking device 200 of FIGS. 4-6, as well as any other ball striking device in accordance with aspects of this invention.

[0076] The inserts 140 described herein may be permanently connected to the face 112, 212 in some embodiments. In other embodiments, the inserts 140 may be removably connected to the face 112, 212 to enable interchanging of the insert 140 with another insert 140 having different properties, to change the properties of the face 112 as desired. The insert 140K shown in FIG. 17 represents an example of an interchangeable insert 140K. In this embodiment, the connectors 143 may be removed to allow one insert 140K to be removed and another insert 140K to be connected, by re-connection of the connectors 143. For a club head 102 having a face 112 with interchangeable inserts 140, the weighting, center of gravity, frictional properties, and/or other properties of the face 112 can be changed by removing the insert 140 and replacing the removed insert 140 with a different insert 140 having one or more different properties. In the embodiment shown in FIG. 17, access to the inner surface 111 of the face 1 12 may be necessary to interchange the insert 140K. When such a face 112 is used in connection with a ball striking device 100 as shown in FIGS. 1-3, the head 102 may include a removable backbody member 129 to provide this access. Several different configurations for removable and/or interchangeable backbody members are shown and described in U.S. Patent Application No. 12/192,402, filed August 15, 2008, which is incorporated by reference herein and made part hereof. However, in other embodiments, an insert 140 may be interchangeable from outside the head 112, 212, either from the outer surface 110, 210 of the face 112, 212 or through access to the inner surface 1 11, 211 without removal of a portion of the body 108, 208. For example, in the head 202 shown in FIGS. 4-6, the inner surface of the insert 140 can be accessed from outside the head 202. Other embodiments of ball striking heads may have portions of the head that are removable by other mechanisms and using other structural configurations, and it is understood that such embodiments are included within the scope of the invention.

[0077] Although the face 112, 212 is described above as having an insert 140 connected thereto, the face 112, 212 can alternately be described as being made from at least two different materials, each having different properties, and may or may not utilize inserts to achieve this configuration. As described above, in one embodiment, the two materials have different densities and/or different friction properties. The different materials may have additional differing properties as well. Additionally, the face 112, 212 may contain more than two different materials, for example, through the use of multiple inserts, an insert made from multiple materials, or a multi-material face. Any of the inserts 140, et seq. described above can be made from multiple materials, which may or may not have different properties. It is understood that in an insert made from multiple materials, different portions of the insert may have different properties (such as density or friction properties). Accordingly, in some embodiments of the inserts 140, et seq. described above, at least a portion of the insert 140, et seq. may have a property (density, friction, etc.) that is different from the property of the face 112, 212, and the insert 140, et seq. may also have two or more portions with properties that are not only different from each other, but also different from the property of the face 112, 212. Likewise, a portion of the insert 140, et seq. may have a different property from the face 112, 212, and another portion may have the same property as the face 112, 212. In other embodiments of single-material or multiple-material inserts 140, et seq., the entire insert may have a property that is different from a property of the face 112, 212. As also described above, in one embodiment, the various different materials each form a portion of the outer surface or ball striking surface 110, 210 of the face 112, 212.

[0078] Heads 102, 202 incorporating the inserts 140, et seq. disclosed herein may be used as a ball striking device or a part thereof. For example, a golf club 100, 200 as shown in FIGS. 1-6 may be manufactured by attaching a shaft or handle 104, 204 to a head that is provided, such as the head 102, 202 as described above. "Providing" the head, as used herein, refers broadly to making an article available or accessible for future actions to be performed on the article, and does not connote that the party providing the article has manufactured, produced, or supplied the article or that the party providing the article has ownership or control of the article. In other embodiments, different types of ball striking devices can be manufactured according to the principles described herein. Manufacturing the head 102 shown in FIGS. 2-3 may include attachment of a backbody member 129 to a face frame member 128, as described above. Additionally, the head 102, 202, golf club 100, 200, or other ball striking device may be fitted or customized for a person by connecting an insert 140, et seq. having a different density and/or friction properties to customize the weighting and/or frictional properties of the face 112, 212. Such customization may include selecting an insert 140, et seq. with specific properties and connecting the insert 140, et seq. to the face 112, 212 in an arrangement to achieve the desired weight distribution of the face 112, 212. Such customization may further include removing one or more inserts 140 and interchanging the removed insert(s) 140 with one or more alternate inserts 140 having at least one different property. Multi-material inserts 140 may be interchanged to achieve desired properties such as higher or lower trajectory, more or less spin, etc. [0079] Heads 102, 202 incorporating the inserts 140, et seq. disclosed herein may be used as part of a kit or assembly that includes a head 102, 202 as described above, along with one or more inserts 140, et seq. configured for connection to the head 102, 202. If the kit includes multiple inserts 140, et seq., each of the inserts 140, et seq. may have different properties. In one embodiment, the head 102, 202 may have a cavity 114 with a specific shape, and the kit may include one or more inserts 140, et seq. having the same shape. In another embodiment, the kit may include inserts 140, et seq. having different shapes, and the head 102, 202 may require further processing to connect an insert 140, et seq. to the face 112, 212, such as by forming a cavity 114 in the face 112, 212. The kit may also include one or more shafts 104, 204 for connection to the head. In some embodiments, the kit may include a plurality of inserts 140, et seq. that are removable and interchangeable with each other.

[0080] The ball striking devices and heads therefor as described herein provide many benefits and advantages over existing products. For example, inserts having various densities and weights can be strategically located and weighted to provide a specific weight distribution of the face. This enables the overall moment of inertia of the head to be changed, such as by adjusting the weight distribution between the center of the face and the edges of the face. This also enables the center of gravity of the face to be moved and/or the relative moment of inertia for various points on the face to be changed, such as by increasing or decreasing the weight of the face in a specific area. Weighting the face in a customized manner can provide superior ball striking function for the head, such as by reducing twisting upon impact. Additionally, the weighting can be customized so that the areas of the face that most frequently impact the ball during play will result in greater energy and velocity transfer and truer and straighter ball flight. As another example, inserts having various friction properties can be used to alter the degree of spin that is imparted to the ball during impacts in a specified area of the face. This enables the club head to be customized to provide specific spin characteristics to the ball during impacts in these areas. Further benefits and advantages are recognized by those skilled in the art.

[0081] While the invention has been described with respect to specific examples including presently preferred modes of carrying out the invention, those skilled in the art will appreciate that there are numerous variations and permutations of the above described systems and methods. Thus, the spirit and scope of the invention should be construed broadly as set forth in the appended claims.

Claims

CLAIMSWhat is claimed is:

1. A golf club head comprising: a face having an outer surface configured for striking a ball; a body connected to the face; and an insert connected to the face and forming a portion of the outer surface, at least a portion of the insert having a density that is lower than a density of a portion of the face bordering the insert.

2. The golf club head of claim 1 , wherein the insert is positioned asymmetrically with respect to a geometric center of the face.

3. The golf club head of claim 2, wherein the face has a center of gravity that is positioned away from a geometric center of the face.

4. The golf club head of claim 1 , wherein a center of gravity of the insert is located away from a geometric center of the face, and a center of gravity of the face is located away from the center of gravity of the insert.

5. The golf club head of claim 4, wherein the center of gravity of the insert is located in one direction from the geometric center of the face, and the center of gravity of the face is located in an opposite direction from the geometric center of the face.

6. The golf club head of claim 1 , wherein the face comprises four quadrants extending from a geometric center of the face, and at least one quadrant contains a greater proportion of the insert, compared to at least one other quadrant.

7. The golf club head of claim 6, wherein each quadrant has a weight distribution that is inversely related to a proportion of the insert located in the respective quadrant.

8. The golf club head of claim 1 , wherein the insert is received in a cavity extending inwardly from the outer surface of the face.

9. The golf club head of claim 1 , wherein the insert is made from multiple materials, and wherein the insert further includes a second portion having a density that is different from the density of the portion of the insert.

10. The golf club head of claim 1, wherein the entire insert has a density that is lower than a density of the portion of the face bordering the insert.

11. A golf club comprising the golf club head of claim 1 and a shaft connected to the golf club head.

12. The golf club head of claim 1, wherein at least a portion of an outer surface of the insert has a friction property that is lower than the friction property of a portion of the face bordering the insert.

13. A golf club comprising the golf club head of claim 12 and a shaft connected to the golf club head.

14. A golf club head comprising : a face having an outer surface configured for striking a ball; a body connected to the face; and an insert connected to the face and forming a portion of the outer surface, the insert having an outer surface, at least a portion of the outer surface of the insert having a lower friction property than a portion of the outer surface of the face bordering the insert.

15. The golf club head of claim 14, wherein the insert is positioned asymmetrically with respect to a geometric center of the face.

16. The golf club head of claim 14, wherein the insert occupies an area of the outer surface, and wherein the area of the outer surface occupied by the insert is configured to impart less spin to an impacting ball than other areas of the outer surface of the face.

17. The golf club head of claim 16, wherein the area of the surface occupied by the insert is configured to impart less backspin to the impacting ball than other areas of the outer surface of the face.

18. The golf club head of claim 14, wherein the face comprises four quadrants extending from a geometric center of the face, and at least one quadrant contains a greater proportion of the insert, compared to at least one other quadrant.

19. The golf club head of claim 14, wherein the insert is received in a cavity extending inwardly from the outer surface of the face.

20. The golf club head of claim 14, wherein the outer surface of the insert is made from multiple materials, at least one of the materials having a friction property that is different from a friction property of another one of the materials.

21. A golf club comprising the golf club head of claim 14 and a shaft connected to the golf club head.

22. A golf club head comprising: a face having a ball striking surface configured for striking a ball; a body connected to the face; and wherein the face comprises a first material having a first density and a first friction property and a second material having a second density and a second friction property, the second density being lower than the first density and the second friction property being lower than the first friction property, and wherein each of the first material and the second material form a portion of the ball striking surface.

23. The golf club head of claim 22, wherein the second material is positioned asymmetrically to a geometric center of the face.

24. The golf club head of claim 22, wherein the second material forms an area of the ball striking surface, and the area of the ball striking surface formed by the second material is configured to impart less spin to an impacting ball then other areas of the ball striking surface.

25. The golf club head of claim 22, wherein the face comprises four quadrants extending from a geometric center of the face, and at least one quadrant contains a greater proportion of the second material, compared to at least one other quadrant.

26. The golf club head of claim 25, wherein each quadrant has a weight distribution that is inversely related to a proportion of the second material located in the respective quadrant.

27. The golf club head of claim 22, wherein the second material forms an area of the face and a center of gravity of the area of the face is located away from a geometric center of the face, and wherein a center of gravity of the face is located away from the center of gravity of the area formed by the second material.

28. A golf club comprising the golf club head of claim 22 and a shaft connected to the golf club head.

29. A golf club head comprising: a face having an outer surface configured for striking a ball; a body connected to the face; and an insert connected to the face and forming a portion of the outer surface, the insert having a density and an outer surface with a friction property, wherein the density and the friction property of the insert are different from a density and a friction property of a portion of the face bordering the insert.

30. The golf club head of claim 29, wherein at least one of the friction property and the density of the insert is lower than the density or friction property of the portion of the face bordering the insert.

31. A golf club comprising the golf club head of claim 29 and a shaft connected to the golf club head.

32. A method of manufacturing a golf club, comprising: providing a golf club head comprising a face having a ball striking surface configured for striking a ball and a body connected to the face; and connecting a first insert to the face, the first insert having a density and a friction property, wherein at least one of the density and the friction property of the first insert is lower than a density or a friction property of a portion of the face bordering the first insert.

33. The method of claim 32, further comprising: removing the first insert from the face; and connecting a second insert to the face, the second insert having a density and a friction property, wherein at least one of the density and the friction property of the second insert are different from a density or a friction property of the first insert.

34. The method of claim 32, further comprising: connecting a shaft to the golf club head to form the golf club.

35. The method of claim 32, wherein the face has a cavity therein, and the first insert is connected to the face by connecting the insert within the cavity.

36. A golf club kit comprising : a golf club head comprising a face having a ball striking surface configured for striking a ball and a body connected to the face; and an insert configured for connection to the face, the insert having a density and a friction property, wherein at least one of the density and the friction property of the insert is lower than a density or a friction property of a portion of the face configured to border the insert.

37. The golf club kit of claim 36, wherein the face has a cavity configured to receive the insert.

38. The golf club kit of claim 36, further comprising: a plurality of inserts, each configured for connection to the face, each insert having a density and a friction property, wherein at least one of the density and the friction property of each insert is lower than a density or a friction property of a portion of the face configured to border each insert.

39. The golf club kit of claim 38, wherein the face has a cavity having a shape, each of the plurality of inserts having a shape that is the same as the shape of the cavity, such that the cavity is configured to receive each of the plurality of inserts.

40. The golf club kit of claim 36, further comprising: a shaft configured for connection to the golf club head to form a golf club.