Patent ID: 12208318

DETAILED DESCRIPTION

In the following description, 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. These terms are not, however, intended to imply absolute relationships, positions, and/or orientations. 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.

As illustrated inFIGS.1-9, a wood-type (e.g., driver or fairway wood) golf club head, such as golf club head2, includes a hollow body10. The body10includes a crown12, a sole14, a skirt16, a striking face, or face portion,18defining an interior cavity79(seeFIGS.7-9). The body10can include a hosel20, which defines a hosel bore24adapted to receive a golf club shaft (seeFIG.6). The body10further includes a heel portion26, a toe portion28, a front portion30, and a rear portion32. The club head2also has a volume, typically measured in cubic-centimeters (cm3), equal to the volumetric displacement of the club head2. In some implementations, the golf club head2has a volume between approximately 420 cm3and approximately 480 cm3, and a total mass between approximately 190 g and approximately 210 g. Referring toFIG.30, in one specific implementation, the golf club head2has a volume of approximately 458 cm3and a total mass of approximately 200 g.

The crown12is defined as an upper portion of the club head (1) above a peripheral outline34of the club head as viewed from a top-down direction; and (2) rearwards of the topmost portion of a ball striking surface22of the striking face18(seeFIG.6). The striking surface22is defined as a front or external surface of the striking face18and is adapted for impacting a golf ball (not shown). In several embodiments, the striking face or face portion18can be a striking plate attached to the body10using conventional attachment techniques, such as welding, as will be described in more detail below. In some embodiments, the striking surface22can have a bulge and roll curvature. For example, referring toFIG.30, the striking surface22can have a bulge and roll each with a radius of approximately 305 mm.

The sole14is defined as a lower portion of the club head2extending upwards from a lowest point of the club head when the club head is ideally positioned, i.e., at a proper address position relative to a golf ball on a level surface. In some implementations, the sole14extends approximately 50% to 60% of the distance from the lowest point of the club head to the crown12, which in some instances, can be approximately 15 mm for a driver and between approximately 10 mm and 12 mm for a fairway wood.

A golf club head, such as the club head2, is at its proper address position when angle15(seeFIG.1) is approximately equal to the golf club head loft and when the golf club head lie angle19(seeFIG.2) is approximately equal to 60 degrees. Angle15is the angle defined between a face plane27, defined as the plane tangent to an ideal impact location23on the striking surface22, and a vertical plane29relative to the ground17. Lie angle19is the angle defined between a longitudinal axis21of the hosel20or shaft and the ground17. The ground, as used herein, is assumed to be a level plane.

The skirt16includes a side portion of the club head2between the crown12and the sole14that extends across a periphery34of the club head, excluding the striking surface22, from the toe portion28, around the rear portion32, to the heel portion26.

In the illustrated embodiment, the ideal impact location23of the golf club head2is disposed at the geometric center of the striking surface22(seeFIG.4). The striking surface22is typically defined as the intersection of the midpoints of a height (Hss) and width (Wss) of the striking surface. See USGA “Procedure for Measuring the Flexibility of a Golf Clubhead,” Revision 2.0. In some implementations, the golf club head2has a height (Hss) between approximately 50 mm and approximately 65 mm, and a width (Wss) between approximately 80 mm and approximately 100 mm. Referring toFIG.30, in one specific implementation, the golf club head2has a height (Hss) of approximately 58.6 mm, width (Wss) of approximately 90.6 mm, and total striking surface area of approximately 3,929 mm2.

In some embodiments, the striking face18is made of a composite material such as described in U.S. Patent Application Publication Nos. 2005/0239575 and 2004/0235584, U.S. patent application Ser. No. 11/642,310, and U.S. Provisional Patent Application No. 60/877,336, which are incorporated herein by reference. In other embodiments, the striking face18is made from a metal alloy (e.g., titanium, steel, aluminum, and/or magnesium), ceramic material, or a combination of composite, metal alloy, and/or ceramic materials. Further, the striking face18can be a striking plate having a variable thickness such as described in U.S. Pat. No. 6,997,820, which is incorporated herein by reference.

The crown12, sole14, and skirt16can be integrally formed using techniques such as molding, cold forming, casting, and/or forging and the striking face18can be attached to the crown, sole and skirt by means known in the art. For example, the striking face18can be attached to the body10as described in U.S. Patent Application Publication Nos. 2005/0239575 and 2004/0235584. The body10can be made from a metal alloy (e.g., titanium, steel, aluminum, and/or magnesium), composite material, ceramic material, or any combination thereof. The wall72of the golf club head2can be made of a thin-walled construction, such as described in U.S. application Ser. No. 11/067,475, filed Feb. 25, 2005, which is incorporated herein by reference. For example, in some implementations, the wall can have a thickness between approximately 0.65 mm and approximately 0.8 mm. In one specific implementation, the wall72of the crown12and skirt16has a thickness of approximately 0.65 mm, and the wall of the sole14has a thickness of approximately 0.8 mm.

A club head origin coordinate system may be defined such that the location of various features of the club head (including, e.g., a club head center-of-gravity (CG)50(seeFIGS.5and6)) can be determined. Referring toFIGS.4-6, a club head origin60is represented on club head2. The club head origin60is positioned at the ideal impact location23, or geometric center, of the striking surface22.

Referring toFIGS.5and6, the head origin coordinate system, as defined with respect to the head origin60, includes three axes: a z-axis65extending through the head origin60in a generally vertical direction relative to the ground17when the club head2is at the address position; an x-axis70extending through the head origin60in a toe-to-heel direction generally parallel to the striking surface22, i.e., generally tangential to the striking surface22at the ideal impact location23, and generally perpendicular to the z-axis65; and a y-axis75extending through the head origin60in a front-to-back direction and generally perpendicular to the x-axis70and to the z-axis65. The x-axis70and the y-axis75both extend in generally horizontal directions relative to the ground17when the club head2is at the address position. The x-axis70extends in a positive direction from the origin60to the heel26of the club head2. The y-axis75extends in a positive direction from the origin60towards the rear portion32of the club head2. The z-axis65extends in a positive direction from the origin60towards the crown12.

In one embodiment, the golf club head can have a CG with an x-axis coordinate between approximately −2 mm and approximately 6 mm, a y-axis coordinate between approximately 33 mm and approximately 41 mm, and a z-axis coordinate between approximately −7 mm and approximately 1 mm. Referring toFIG.30, in one specific implementation, the CG x-axis coordinate is approximately 1.8 mm, the CG y-axis coordinate is approximately 37.1 mm, and the CG z-axis coordinate is approximately −3.26 mm.

Referring toFIG.4, club head2has a maximum club head height (Hch) defined as the distance between the lowest and highest points on the outer surface of the body10measured along an axis parallel to the z-axis when the club head2is at proper address position; a maximum club head width (Wch) defined as the distance between the maximum extents of the heel and toe portions26,28of the body measured along an axis parallel to the x-axis when the club head2is at proper address position; and a maximum club head depth (Dch), or length, defined as the distance between the forwardmost and rearwardmost points on the surface of the body10measured along an axis parallel to the y-axis when the club head2is at proper address position. The height and width of club head2is measured according to the USGA “Procedure for Measuring the Clubhead Size of Wood Clubs” Revision 1.0. In some implementations, the golf club head2has a height (Hch) between approximately 55 mm and approximately 75 mm, a width (Wch) between approximately 110 mm and approximately 130 mm, and a depth (Dch) between approximately 110 mm and approximately 130 mm. Referring toFIG.30, in one specific implementation, the golf club head2has a height (Hch) of approximately 60.7 mm, width (Wch) of approximately 120.5 mm, and depth (Dch) of approximately 115 mm.

In certain embodiments, the club head2includes a rib82extending along an interior surface of the sole14and skirt16generally parallel to the striking face18. In some instances, the rib82provides structural rigidity to the club head2and vibrational dampening. Although club head2includes a single rib82, in some implementations, the club head2includes multiple ribs82. Further, in some implementations, the rib82extends along only the sole14or includes two spaced-apart portions each extending along the skirt16on separate sides of the club head.

Referring toFIGS.5and6, golf club head moments of inertia are typically defined about three axes extending through the golf club head CG50: (1) a CG z-axis85extending through the CG50in a generally vertical direction relative to the ground17when the club head2is at address position; (2) a CG x-axis90extending through the CG50in a heel-to-toe direction generally parallel to the striking surface22and generally perpendicular to the CG z-axis85; and (3) a CG y-axis95extending through the CG50in a front-to-back direction and generally perpendicular to the CG x-axis90and the CG z-axis85. The CG x-axis90and the CG y-axis95both extend in a generally horizontal direction relative to the ground17when the club head2is at the address position.

A moment of inertia about the golf club head CG x-axis90is calculated by the following equation
Ixx=∫(y2+z2)dm(1)
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-axis90and the golf club head CG z-axis85. The CG xy-plane is a plane defined by the golf club head CG x-axis90and the golf club head CG y-axis95.

A moment of inertia about the golf club head CG z-axis85is calculated by the following equation
Izz=∫(x2+y2)dm(2)
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-axis95and the golf club head CG z-axis85.

As the moment of inertia about the CG z-axis (Izz) is an indication of the ability of a golf club head to resist twisting about the CG z-axis, the moment of inertia about the CG x-axis (Ixx) is an indication of the ability of the golf club head to resist twisting about the CG x-axis. The higher the moment of inertia about the CG x-axis (Ixx), the greater the forgiveness of the golf club head on high and low off-center impacts with a golf ball. In other words, a golf ball hit by a golf club head on a location of the striking surface18above the ideal impact location23causes the golf club head to twist upwardly and the golf ball to have a higher launch angle and lower spin than desired. Similarly, a golf ball hit by a golf club head on a location of the striking surface18below the ideal impact location23causes the golf club head to twist downwardly and the golf ball to have a lower launch angle and higher spin than desired. Both high and low off-center hits also cause loss of ball speed compared to centered hits. Increasing the moment of inertia about the CG x-axis (Ixx) reduces upward and downward twisting of the golf club head to reduce the negative effects of high and low off-center impacts.

As discussed above, many conventional golf club heads are designed to achieve a moment of inertia about the CG z-axis (Izz) that approaches the maximum moment of inertia allowable by the USGA in order to increase straightness of the shot and reduce ball speed-loss, i.e., forgiveness on heel and toe off-center hits. However, few, if any, conventional golf club heads are designed to achieve a high moment of inertia about the CG x-axis (Ixx) in conjunction with a high moment of inertia about the CG z-axis (Izz). Moreover, the prior art does not recognize the need to, nor the advantages associated with, configuring a golf club head to have an increased moment of inertia about the CG x-axis (Ixx) while maintaining a specific ratio of the moment of inertia about the CG x-axis (Ixx) to the moment of inertia about the CG z-axis, i.e., Ixx/Izz.

Increasing the moment of inertia about the CG x-axis (Ixx) typically does not involve distributing additional mass away from the hosel and shaft. Accordingly, the moment of inertia about the CG x-axis (Ixx) can be increased without significantly affecting the ability of a golfer to square the club head at impact. Therefore, a golf club head can have a moderately high moment of inertia about the CG z-axis (Izz) and an increased moment of inertia about the CG x-axis (Ixx) to provide a golf club head with a high forgiveness on high, low, heel and toe off-center impacts without negatively impacting a golfer's ability to square the golf club head. Further, a given head design offers only so much discretionary mass that can be used to achieve specific moments of inertia, e.g., moment of inertia about the CG x-axis (Ixx) and/or moment of inertia about the CG z-axis (Izz). Thus, it is often not desirable to utilize all or most of the discretionary mass to achieve a selected moment of inertia about the CG z-axis (Izz), in part because increases in moment of inertia about the CG z-axis (Izz) beyond about 500 kg·mm2accrue proportionately less benefit. In such instances, it is often desirable to maintain moment of inertia about the CG z-axis (Izz) and redistribute mass to achieve an increase in moment of inertia about the CG x-axis (Ixx) and thus an increase in the ratio of moment of inertia about the CG x-axis (Ixx) to moment of inertia about the CG z-axis (Izz).

As moments of inertia are proportional to the square of the distance of the mass away from an axis of rotation, according to several embodiments, golf club heads described herein can include one or more localized or discrete mass elements positioned at strategic locations about the golf club head to affect the moments of the inertia of the head without increasing the bulk of the golf club head. Further, in some embodiments, using localized or discrete mass elements in conjunction with body a made of a thin-walled construction can provide desirable mass properties without the need for composite materials, which can lead to increased material and manufacturing costs.

Referring toFIGS.7-9, golf club2includes a localized heel mass element74and rear mass element76. A mass element can be defined as an individual structure having a mass, or a plurality of localized structures each having a mass, secured to a wall of a golf club head or integrally formed as a one-piece construction with and extending from the wall of a golf club head. Although an integrally formed mass element can be described as a build-up of wall thickness, a portion of the built-up wall thickness contiguous with, and having the same general thickness as, the wall surrounding the mass element does not form part of the mass element, and thus is not included in the mass or center of gravity determination of the mass element.

The mass elements74,76can be positioned within the interior cavity79and secured to, or be formed integrally with, respective inner surfaces of wall72or striking face18. As shown, the mass elements74,76are formed integrally with, and extend inwardly from, wall72or striking face18of body10to form a localized area of increased or built-up wall thickness. The heel mass element74is positioned on the skirt14at the heel portion26of the golf club head2proximate the front portion30. The rear mass element76extends inwardly from the sole14, skirt16, and crown12and is positioned proximate the rear portion32of the golf club head2.

The location of each mass element74,76on the golf club head can be defined as the location of the center of gravity of the mass element relative to the club head origin coordinate system. For example, in some implementations, the heel mass element74has an origin x-axis coordinate between approximately 35 mm and approximately 65 mm, an origin y-axis coordinate between approximately 0 mm and approximately 30 mm, and an origin z-axis coordinate between approximately −20 mm and approximately 10 mm. In one specific implementation, the heel mass element74has an origin x-axis coordinate of approximately 50 mm, an origin y-axis coordinate of approximately 15 mm, and an origin z-axis coordinate of approximately −3 mm. Similarly, in some implementations, the rear mass element76has an origin x-axis coordinate between approximately −20 mm and approximately 10 mm, an origin y-axis coordinate between approximately 90 mm and approximately 120 mm, and an origin z-axis coordinate between approximately −20 mm and approximately 10 mm. In one specific implementation, the rear mass element76has an origin x-axis coordinate of approximately −7 mm, an origin y-axis coordinate of approximately 106 mm, and an origin z-axis coordinate of approximately −3 mm.

Further, the mass elements74,76can have any one of various masses. For example, in some implementations, the heel mass element74has a mass between about 3 g and about 23 g and the rear mass element76has a mass between about 15 g and about 35 g. In one specific implementation, the heel mass element74has a mass of approximately 6 g and the rear mass element76has a mass of approximately 24 g.

The configuration of the golf club head2, including the locations and mass of the mass elements74,76, can, in some implementations, result in the club head2having a moment of inertia about the CG z-axis (Izz) between about 450 kg·mm2and about 600 kg·mm2, and a moment of inertia about the CG x-axis (Ixx) between about 280 kg·mm2and about 400 kg·mm2. In one specific implementation having the mass element locations and masses indicated inFIG.30, club head2has a moment of inertia about the CG z-axis (Izz) of approximately 528 kg·mm2and a moment of inertia about the CG x-axis (Ixx) of approximately 339 kg·mm2. In this implementation, then, the ratio of Ixx/Izz is approximately 0.64. However, in other implementations, the ratio of Ixx/Izz is between about 0.5 kg·mm2and about 0.9 kg·mm2.

Referring toFIGS.10-16, and according to another exemplary embodiment, golf club head100has a body110with a crown112, sole114, skirt116, and striking face118defining an interior cavity157. The body110further includes a hosel120, heel portion126, a toe portion128, a front portion130, a rear portion132, and an internal rib182. The striking face118includes an outwardly facing ball striking surface122having an ideal impact location at a geometric center123of the striking surface. In some implementations, the golf club head100has a volume between approximately 420 cm3and approximately 480 cm3, and a total mass between approximately 190 g and approximately 210 g. Referring toFIG.30, in one specific implementation, the golf club head100has a volume of approximately 454 cm3and a total mass of approximately 202.8 g.

Unless otherwise noted, the general details and features of the body110of golf club head100can be understood with reference to the same or similar features of the body10of golf club head2.

The sole114extends upwardly from the lowest point of the golf club head100a shorter distance than the sole14of golf club head2. For example, in some implementations, the sole114extends upwardly approximately 20% to 40% of the distance from the lowest point of the club head100to the crown112, which in some instances, can be approximately 15 mm for a driver and between approximately 10 mm and approximately 12 mm for a fairway wood. Further, the sole114comprises a substantially flat portion119extending horizontal to the ground117when in proper address position. In some implementations, the bottommost portion of the sole114extends substantially parallel to the ground117between approximately 70% and approximately 40% of the depth (Dch) of the golf club head100.

Because the sole114of golf club head100is shorter than the sole12of golf club head2, the skirt116is taller, i.e., extends a greater approximately vertical distance, than the skirt16of golf club head2. In at least one implementation, the golf club head100includes a weight port140formed in the skirt116proximate the rear portion132of the club head (seeFIG.12). The weight port140can 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. patent application Ser. Nos. 11/066,720 and 11/065,772, which are incorporated herein by reference.

In some implementations, the striking surface122golf club head100has a height (Hss) between approximately 50 mm and approximately 65 mm, and a width (Wss) between approximately 80 mm and approximately 100 mm. Referring toFIG.30, in one specific implementation, the golf club head100has a height (Hss) of approximately 59.6 mm, width (Wss) of approximately 90.6 mm, and total striking surface area of approximately 4,098 mm2.

In one embodiment, the golf club head100has a CG with an x-axis coordinate between approximately −2 mm and approximately 6 mm, a y-axis coordinate between approximately 33 mm and approximately 41 mm, and a z-axis coordinate between approximately −8 mm and approximately 0 mm. Referring toFIG.30, in one specific implementation, the CG x-axis coordinate is approximately 2.0 mm, the CG y-axis coordinate is approximately 37.9 mm, and the CG z-axis coordinate is approximately −4.67 mm.

In some implementations, the golf club head100has a height (Hch) between approximately 55 mm and approximately 75 mm, a width (Wch) between approximately 110 mm and approximately 130 mm, and a depth (Dch) between approximately 110 mm and approximately 130 mm. Referring toFIG.30, in one specific implementation, the golf club head100has a height (Hch) of approximately 62.2 mm, width (Wch) of approximately 119.3 mm, and depth (Dch) of approximately 110.7 mm.

Referring toFIGS.14-16, golf club head100includes a localized heel mass element174and rear mass element176. In some implementations, the heel mass element174has an origin x-axis coordinate between approximately 35 mm and approximately 65 mm, an origin y-axis coordinate between approximately 10 mm and approximately 40 mm, and an origin z-axis coordinate between approximately −25 mm and approximately 5 mm. In one specific implementation, the heel mass element174has an origin x-axis coordinate of approximately 50 mm, an origin y-axis coordinate of approximately 25 mm, and an origin z-axis coordinate of approximately −10 mm. Similarly, in some implementations, the rear mass element176has an origin x-axis coordinate between approximately −15 mm and approximately 15 mm, an origin y-axis coordinate between approximately 90 mm and approximately 120 mm, and an origin z-axis coordinate between approximately −20 mm and approximately 10 mm. In one specific implementation, the rear mass element176has an origin x-axis coordinate of approximately 0 mm, an origin y-axis coordinate of approximately 103 mm, and an origin z-axis coordinate of approximately −4 mm.

Like mass elements74,76, the mass elements174,176can have any one of various masses. For example, in some implementations, the heel mass element174has a mass between about 3 g and about 23 g and the rear mass element176has a mass between about 10 g and about 30 g. In one specific implementation, the heel mass element174has a mass of approximately 6 g and the rear mass element176has a mass of approximately 19 g.

The configuration of the golf club head100, including the locations and mass of the mass elements174,176, can, in some implementations, result in the club head having a moment of inertia about the CG z-axis (Izz) between about 450 kg·mm2and about 600 kg·mm2, and a moment of inertia about the CG x-axis (Ixx) between about 280 kg·mm2and about 400 kg·mm2. In one specific implementation having mass element locations and masses indicated inFIG.30, club head100has a moment of inertia about the CG z-axis (Izz) of approximately 498 kg·mm2and a moment of inertia about the CG x-axis (Ixx) of approximately 337 kg·mm2. In this implementation, then, the ratio of Ixx/Izz is approximately 0.68. However, in other implementations, the ratio of Ixx/Izz is between about 0.5 and about 0.9.

Referring toFIGS.17-21, and according to another exemplary embodiment, golf club head200has a body210with a low skirt similar to body110of golf club head100. The body210includes a crown212, a sole214, a skirt216, a striking face218defining an interior cavity257. The body210further includes a hosel220, heel portion226, toe portion228, front portion230, and rear portion232. The striking face218includes an outwardly facing ball striking surface222having an ideal impact location at a geometric center223of the striking surface. In some implementations, the golf club head200has a volume between approximately 420 cm3and approximately 480 cm3, and a total mass between approximately 190 g and approximately 210 g. Referring toFIG.30, in one specific implementation, the golf club head200has a volume of approximately 454 cm3and a total mass of approximately 202.8 g.

Unless otherwise noted, the general details and features of the body210of golf club head200can be understood with reference to the same or similar features of the body10of golf club head2and body110of golf club head100.

Like sole114of golf club head100, the sole214extends upwardly approximately 20% to 40% of the distance from the lowest point of the club head200to the crown212. Therefore, the skirt216is taller, i.e., extends a greater approximately vertical distance, than the skirt16of golf club head2.

In at least one implementation, and shown inFIGS.18and21, the golf club head200includes a weight port240formed in the sole114proximate the rear portion232of the club head. The weight port240can have any of a number of various configurations to receive and retain any of a number of weights or weight assemblies. For example, as shown, the weight port240extends substantially vertically from the wall272of the body210upwardly into the interior cavity257.

In some implementations, the striking surface222golf club head200has a height (Hss) between approximately 50 mm and approximately 65 mm, and a width (Wss) between approximately 80 mm and approximately 100 mm. Referring toFIG.30, in one specific implementation, the golf club head200has a height (Hss) of approximately 56.8 mm, width (Wss) of approximately 92.3 mm, and total striking surface area of approximately 4,100 mm2.

In one embodiment, the golf club head200has a CG with an x-axis coordinate between approximately −2 mm and approximately 6 mm, a y-axis coordinate between approximately 33 mm and approximately 41 mm, and a z-axis coordinate between approximately −8 mm and approximately 0 mm. Referring toFIG.30, in one specific implementation, the CG x-axis coordinate is approximately 2.3 mm, the CG y-axis coordinate is approximately 36.7 mm, and the CG z-axis coordinate is approximately −4.65 mm.

In some implementations, the golf club head200has a height (Hch) between approximately 55 mm and approximately 75 mm, a width (Wch) between approximately 110 mm and approximately 130 mm, and a depth (Dch) between approximately 110 mm and approximately 130 mm. Referring toFIG.30, in one specific implementation, the golf club head200has a height (Hch) of approximately 61.5 mm, width (Wch) of approximately 122.8 mm, and depth (Dch) of approximately 113.5 mm.

Referring toFIGS.20and21, golf club head200includes a localized heel mass element274and rear mass element276. In some implementations, the heel mass element274has an origin x-axis coordinate between approximately 35 mm and approximately 65 mm, an origin y-axis coordinate between approximately 10 mm and approximately 40 mm, and an origin z-axis coordinate between approximately −15 mm and approximately 5 mm. In one specific implementation, the heel mass element274has an origin x-axis coordinate of approximately 50 mm, an origin y-axis coordinate of approximately 21 mm, and an origin z-axis coordinate of approximately −11 mm. Similarly, in some implementations, the rear mass element276has an origin x-axis coordinate between approximately −15 mm and approximately 15 mm, an origin y-axis coordinate between approximately 95 mm and approximately 125 mm, and an origin z-axis coordinate between approximately −30 mm and approximately 0 mm. In one specific implementation, the rear mass element276has an origin x-axis coordinate of approximately −1 mm, an origin y-axis coordinate of approximately 106 mm, and an origin z-axis coordinate of approximately −18 mm.

Like mass elements74,76, the mass elements274,276can have any one of various masses or weights. For example, in some implementations, the heel mass element274has a mass between about 3 g and about 23 g and the rear mass element276has a mass between about 5 g and about 25 g. In one specific implementation, the heel mass element274has a mass of approximately 5 g and the rear mass element276has a mass of approximately 8 g.

The configuration of the golf club head200, including the locations and mass of the mass elements274,276, can, in some implementations, result in the club head having a moment of inertia about the CG z-axis (Izz) between about 450 kg·mm2and about 600 kg·mm2, and a moment of inertia about the CG x-axis (Ixx) between about 280 kg·mm2and about 400 kg·mm2. In one specific implementation having mass element locations and masses indicated inFIG.30, club head200has a moment of inertia about the CG z-axis (Izz) of approximately 495 kg·mm2and a moment of inertia about the CG x-axis (Ixx) of approximately 333 kg·mm2. In this implementation, then, the ratio of Ixx/Izz is approximately 0.67. However, in other implementations, the ratio of Ixx/Izz is between about 0.5 and about 0.9.

Referring toFIGS.22-26, and according to another exemplary embodiment, golf club head300has a body310that includes a crown312, a sole314, a skirt316, a striking face318defining an interior cavity357. The body310further includes a hosel320, heel portion326, toe portion328, front portion330, and rear portion332. The striking face318includes an outwardly facing ball striking surface322having an ideal impact location at a geometric center323of the striking surface. The club head300also has a volume, typically measured in cubic-centimeters (cm3), equal to the volumetric displacement of the club head300. In some implementations, the golf club head300has a volume between approximately 420 cm3and approximately 480 cm3, and a total mass between approximately 190 g and approximately 210 g. Referring toFIG.30, in one specific implementation, the golf club head300has a volume of approximately 453 cm3and a total mass of approximately 202.3 g.

Unless otherwise noted, the general details and features of the body310of golf club head300can be understood with reference to the same or similar features of the body10of golf club head2, body110of golf club head100and body210of golf club head200.

Like soles114,214, the sole314extends upwardly approximately 20% to 40% of the distance from the lowest point of the club head300to the crown312. Like skirts116,216, the skirt316is taller, i.e., extends a greater approximately vertical distance, than the skirt16of golf club head2. However, unlike, skirts116,216, skirt316includes an inverted portion352having a substantially concave outer surface336extending about at least a substantial portion of the toe portion328of the golf club head300.

Similar to the golf club head described in U.S. patent application Ser. No. 11/565,485, which is incorporated herein by reference, golf club head300includes a rib350that has an external portion356and two internal portions358,360(seeFIGS.24and25). The external portion356is positioned along and projects from the external surface336of the concave portion330. The internal portions358,360are positioned within the internal cavity357of the body302and project from an internal surface338of the body. The external portion356is positioned between the first and second internal portions358,360and is coupled to the internal portions via respective first and second rib transition regions (not shown) formed in a wall372of the body310. Rib350extends generally parallel to a striking surface322of striking face318of the golf club head300along the toe portion328of the body310. More specifically, the rib350extends along the toe potion328of the body310upwardly from the sole314, along the skirt316, to the crown312.

In some implementations, the striking surface322golf club head300has a height (Hss) between approximately 50 mm and approximately 65 mm, and a width (Wss) between approximately 80 mm and approximately 100 mm. Referring toFIG.30, in one specific implementation, the golf club head300has a height (Hss) of approximately 57.2 mm, width (Wss) of approximately 90.6 mm, and total striking surface area of approximately 3,929 mm2.

In one embodiment, the golf club head300has a CG with an x-axis coordinate between approximately −2 mm and approximately 6 mm, a y-axis coordinate between approximately 33 mm and approximately 41 mm, and a z-axis coordinate between approximately −6 mm and approximately 2 mm. Referring toFIG.30, in one specific implementation, the CG x-axis coordinate is approximately 3.3 mm, the CG y-axis coordinate is approximately 30.1 mm, and the CG z-axis coordinate is approximately −0.09 mm.

In some implementations, the golf club head300has a height (Hch) between approximately 53 mm and approximately 73 mm, a width (Wch) between approximately 105 mm and approximately 125 mm, and a depth (Dch) between approximately 105 mm and approximately 125 mm. Referring toFIG.30, in one specific implementation, the golf club head300has a height (Hch) of approximately 59 mm, width (Wch) of approximately 117.2 mm, and depth (Dch) of approximately 117.2 mm.

Referring toFIGS.25and26, golf club head300includes a localized heel mass element374, rear mass element376and toe mass element378. The toe mass element378is similar to the heel mass element374, but positioned on the skirt314at the toe portion328of the golf club head310proximate the front portion330.

In some implementations, the heel mass element374has an origin x-axis coordinate between approximately 35 mm and approximately 65 mm, an origin y-axis coordinate between approximately 10 mm and approximately 40 mm, and an origin z-axis coordinate between approximately 0 mm and approximately 20 mm. In one specific implementation, the heel mass element374has an origin x-axis coordinate of approximately 53 mm, an origin y-axis coordinate of approximately 21 mm, and an origin z-axis coordinate of approximately 7 mm. Similarly, in some implementations, the rear mass element376has an origin x-axis coordinate between approximately −25 mm and approximately 5 mm, an origin y-axis coordinate between approximately 90 mm and approximately 120 mm, and an origin z-axis coordinate between approximately −5 mm and approximately 25 mm. In one specific implementation, the rear mass element376has an origin x-axis coordinate of approximately −10 mm, an origin y-axis coordinate of approximately 109 mm, and an origin z-axis coordinate of approximately 10 mm.

Like mass elements74,76, the mass elements374,376can have any one of various masses or weights. For example, in some implementations, the heel mass element374has a mass between about 5 g and about 25 g and the rear mass element376has a mass between about 10 g and about 30 g. In one specific implementation, the heel mass element374has a mass of approximately 11 g and the rear mass element376has a mass of approximately 21 g.

The configuration of the golf club head300, including the locations and mass of the mass elements374,376, can, in some implementations, result in the club head having a moment of inertia about the CG z-axis (Izz) between about 450 kg·mm2and about 600 kg·mm2, and a moment of inertia about the CG x-axis (Ixx) between about 280 kg·mm2and about 400 kg·mm2. In one specific implementation having mass element locations and masses indicated inFIG.30, club head300has a moment of inertia about the CG z-axis (Izz) of approximately 536 kg·mm2and a moment of inertia about the CG x-axis (Ixx) of approximately 336 kg·mm2. In this implementation, then, the ratio of Ixx/Izz is approximately 0.63. However, in other implementations, the ratio of Ixx/Izz is between about 0.5 and about 0.9.

One specific exemplary implementation of a golf club head400having a generally rectangular ball striking face with a corresponding rectangular ball striking surface410is shown inFIGS.27-29. The golf club head400includes a body420having a hosel421and four generally planar sides, i.e., top side422, right side424, left side426, and bottom side428. The sides422,424,426,428extend in a tapering manner from the ball striking surface410at a forward portion430of the golf club head and converging at a generally square end440at a rearward portion442of the golf club head. Accordingly, the surface area of the ball striking surface410is larger than the cross-sectional surface areas of the body420along planes parallel to the striking surface. The golf club head400includes a club head origin416positioned at the geometric center of the striking surface410. The origin416acts as the origin of a golf club head coordinate system, similar to that described above, of the golf club head400.

In the illustrated embodiment, the edges, or intersections, between the sides422,424,426,428, striking surface410and end440appear relatively sharp. Of course, any one or more of the sharp edges between the sides, striking surface and end can be eased or radiused without departing from the general relationships. In general, the golf club head400has a generally pyramidal, prismatic, pyramidal frustum, or prismatic frustum shape. When viewed from above, or in plan view, the golf club head has a generally triangular or trapezoidal shape.

In one specific implementation, for optimum forgiveness and playability, the ball striking surface410has the maximum allowable surface area under current USGA dimensional constraints for golf club heads. In other words, the ball striking surface410has a maximum height (H) of approximately 71 mm (2.8 inches) and a maximum width (W) of approximately 125 mm (5 inches). Accordingly, the ball striking surface410has an area of approximately 8,875 mm2. In other embodiments, the ball striking surface410may have a maximum height (H) between about 67 mm to about 71 mm, a maximum width (W) between about 118 mm to about 125 mm, and a corresponding ball striking surface area of between about 7,900 mm2to about 8,875 mm2.

In certain implementations, the golf club head400has a maximum depth (D) equal to the maximum allowable depth under current USGA dimensional constraints, i.e., approximately 125 mm. In other embodiments, the golf club head400may have a maximum depth (D) between about 118 mm to about 125 mm. In some implementations, the golf club head400has a volume equal to the maximum allowable volume under current USGA dimensional constraints, i.e., approximately 460 cm3. The area of the square end440may range from about 342 mm2to about 361 mm2.

The golf club head400includes one or more discrete mass elements. For example, in the illustrated embodiments, the golf club head400includes three discrete mass elements: heel mass element474, rear mass element476and toe mass element478. Each mass element474,476,478is defined by its location about the golf club head400and mass. The location of the mass elements about the golf club head are described according to the coordinates of the mass element CG on the golf club head origin coordinate system.

The golf club head400can be configured according to any one of various configurations, e.g., golf club head configurations400A-400G, each having a unique mass element location and weight to achieve specific moments of inertia Ixx and Izz, and a specific Ixx/Izz ratio. The body420of each configuration400A-400G is constructed of a composite material and the total mass of the golf club head400of each configuration400A-400G is approximately 203 g.

Referring toFIG.31, the locations and masses of the heel mass element474, rear mass element476and toe mass element478, as well as the resulting moments of inertia characteristics, for golf club head configurations400A-400G are shown. As shown, for each golf club head configuration400A-400G, the moment of inertia about the CG x-axis (Ixx) is between approximately 427 kg·mm2and approximately 525 kg·mm2, the moment of inertia about the CG z-axis (Izz) is between approximately 447 kg·mm2and approximately 702 kg·mm2, and the Ixx/Izz ratio is between approximately 0.66 and approximately 0.96.

As indicated inFIG.31, the location and weight of the three concentrated mass elements has a significant impact on the Ixx/Izz ratio for a given moment of inertia about the CG z-axis (Izz) or CG x-axis (Ixx). For example, golf club head configuration400A has a moment of inertia about the CG x-axis (Ixx) of approximately 427 kg·mm2and a moment of inertia about the CG z-axis (Izz) of approximately 645 kg·mm2to achieve an Ixx/Izz ratio of approximately 0.66. Although the moments of inertia about the CG x-axis (Ixx) and z-axis (Izz) provide high forgiveness on high/low and left/right off-center hits, respectively, the moment of inertia about the CG z-axis (Izz) for this configuration may make it difficult for a golfer to square the club head prior to impact with a golf ball.

As perhaps a more preferable configuration compared to configuration400A, golf club head configuration400B can be accomplished by configuring the golf club head to have a toe mass element478that is closer to the heel mass element474than configuration400A. The resultant golf club head configuration400B has the same moment of inertia about the CG x-axis (Ixx) as configuration400A, but has a moment of inertia about the CG z-axis (Izz), i.e., approximately 593 kg·mm2, that is less than configuration400A to achieve a slightly higher Ixx/Izz ratio of approximately 0.72. Although golf club head configuration400B has a lower moment of inertia about the CG z-axis (Izz) than configuration400B, the moment of inertia is still sufficiently high to provide high forgiveness for left/right off-center hits, while allowing a golfer to more easily square the golf club head prior to impact.

For more case in squaring the golf club head prior to impact, configuration400C includes heel and toe mass elements474,478that are closer to each other than configuration400B to reduce the moment of inertia about the CG z-axis (Izz) and maintain the moment of inertia about the CG x-axis (Ixx) compared to configuration400C. Accordingly, configuration400C maintains a very high moment of inertia about the CG x-axis (Ixx) for alleviating the negative effects of high/low impacts and achieves a high moment of inertia about the CG z-axis (Izz) for alleviating the negative effects of right/left impacts. The resultant Ixx/Izz ratio of configuration400C of approximately 0.96 is significantly higher than the ratio of configuration400B.

Configuration400D has a moment of inertia about its z-axis (Izz) and an Ixx/Izz ratio that falls between configuration400B and configuration400C.

Configurations400E-400G follow a similar pattern compared to configurations400B-400D. More specifically, configuration400F has a moment of inertia about its z-axis (Izz) and an Ixx/Izz ratio that falls between configuration400E and configuration400G. However, the configurations400E-400G differ from configurations400B-400D in several respects. Most significantly, the heel and toe mass elements474,478of respective configurations400E-400G have less weight than the heel and toe mass elements474,478of respective configurations400B-400D. Additionally, the rear mass elements476of respective configurations400E-400G have more weight than the rear mass elements476of respective configurations400B-400D. In other words, more weight is concentrated in the rear of configurations400E-400G than in configurations400B-400D. The result is that the configurations400E-400G have moments of inertia about respective CG x-axes (Ixx) that are significantly higher than the same moments of inertia achieved by configurations400B-400C, while the Ixx/Izz ratios of corresponding configurations remain proportionally similar.

Referring toFIG.32, the Ixx/Izz ratio verses the moment of inertia about the z-axis (Izz) for each of the various golf club head embodiments described above is shown. Also shown is the Ixx/Izz ratio verses the moment of inertia about the z-axis (Izz) for a plurality of conventional golf club heads. The conventional golf club heads shown have moments of inertia about their respective CG z-axes (Izz) between about 250 kg·mm2and 480 kg·mm2, and Ixx/Izz ratios between approximately 0.45 and 0.78. However, no individual conventional golf club head has (1) a moment of inertia about its CG z-axis (Izz) greater than approximately 480 kg·mm2and an Ixx/Izz ratio greater than approximately 0.6; or (2) a moment of inertia about its CG z-axis (Izz) greater than approximately 440 kg·mm2and an Ixx/Izz ratio greater than 0.8.

In view of the many possible embodiments to which the principles of the disclosed golf club head 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 golf club head. Rather, the scope of the invention is defined by the following claims. We therefore claim as our invention all that comes within the scope and spirit of these claims and their equivalents.