WO2008011334A2

WO2008011334A2 - Golf club with high moment of inertia

Info

Publication number: WO2008011334A2
Application number: PCT/US2007/073392
Authority: WO
Inventors: Matthew T. Cackett; Alan Hocknell; Daniel M. Stevens; Luke R. Williams
Original assignee: Callaway Golf Company
Priority date: 2006-07-20
Filing date: 2007-07-12
Publication date: 2008-01-24
Also published as: US7559851B2; US20060293120A1; GB0814706D0; WO2008011334A3; GB2448105B; GB2448105A; US20090275419A1; US7674187B2; JP2009544358A; KR20090037987A

Abstract

A golf club (40) has a golf club head with a large mass, relatively short club length and a moment of inertia about the Izz axis through the center of gravity of the golf club head greater than 5000 grams-centimeters squared. The golf club head (42) preferably has a volume ranging from 400 cubic centimeters to 470 cubic centimeters. The golf club head (42) preferably has a moment of inertia about the Ixx axis through the center of gravity of the golf club head greater than 3000 grams- centimeters squared. The golf club (40) preferably has an inertia ratio greater than 0.0019.

Description

Title

GOLF CLUB WITH HIGH MOMENT OF INERTIA (Corporate Docket Number PU2392-WO)

Technical Field

The present invention relates to a golf club head and golf club. More specifically, the present invention relates to a golf club head with a high moment of inertia and a golf club with a high moment of inertia.

Background Art

When a golf club head strikes a golf ball, large impacts are produced that load the club head face and the golf ball. Most of the energy is transferred from the head to the golf ball, however, some energy is lost as a result of the collision. The golf ball is typically composed of polymer cover materials (such as ionomers) surrounding a rubber-like core. These softer polymer materials having damping (loss) properties that are strain and strain rate dependent which are on the order of 10-100 times larger than the damping properties of a metallic club face. Thus, during impact most of the energy is lost as a result of the high stresses and deformations of the golf ball (0.001 to 0.20 inch), as opposed to the small deformations of the metallic club face (0.025 to 0.050 inch). A more efficient energy transfer from the club head to the golf ball could lead to greater flight distances of the golf ball.

The generally accepted approach has been to increase the stiffness of the club head face to reduce metal or club head deformations. However, this leads to greater deformations in the golf ball, and thus increases in the energy transfer problem. Some have recognized the problem and disclosed possible solutions. An example is Campau, U.S. Patent Number 4,398,965, for a Method Of Making Iron Golf Clubs With Flexible Impact Surface, which discloses a club having a flexible and resilient face plate with a slot to allow for the flexing of the face plate. The face plate of Campau is composed of a ferrous material, such as stainless steel, and has a thickness in the range of 0.1 inches to 0.125 inches.

Another example is Eggiman, U.S. Patent Number 5,863,261, for a Golf Club Head With Elastically Deforming Face And Back Plates, which discloses the use of a plurality of plates that act in concert to create a spring-like effect on a golf ball during impact. A fluid is disposed between at least two of the plates to act as a viscous coupler.

U.S. Patents 5,570,886 and 5,547,427 to Rigal, et al, disclose a golf club head of molded thermoplastic having a striking face defined by an impact-resistant metallic sealing element. The sealing element defines a front wall of the striking surface of the club head and extends upward and along the side of the impact surface to form a neck for attachment of the shaft to the club head. The sealing element preferably being between 2.5 and 5 mm in thickness.

U.S. Patent Number 3,981,507 to Nunziato discloses a cube-like club head to provide a rectangular face. U.S. Patent Number 2,336,405 to Kent discloses a golf club with a trapezoidal shaped club head.

U.S. Patent Number D226,431 to Baker discloses a design for a club head with a greater rear-wall.

U.S. Patent Number 3,397,888 to Springer et al., discloses a putter head with a rectangular shape.

U.S. Patent Number 3,486,755 to Hodge discloses a putter with a triangular- like shape.

U.S. Patent 3,901,514 discloses a putter with a club head shaped like a ring. U.S. Patent Number Dl 79,002 to Hoffmeister discloses a design for a club head with a circular face and an elongated body.

Existing large volume driver heads (>400cc) composed of conventional materials (titanium, steel) and conventional manufacturing methods (casting, forging, MIM, machining, etc.) are limited in the amount of discretionary material available for increasing the moments of inertia of the golf club head. Conventional golf club head shapes also limit the moments of inertia possible for any given volume golf club head.

Summary of the Invention One aspect of the present invention is a golf club head with a moment of inertia, Izz, about the center of gravity of the golf club head that exceeds 5000 grams- centimeters squared.

Another aspect of the present invention is a golf club head having a volume ranging from 400 cubic centimeters to 470 cubic centimeters, a mass ranging from 210 grams to 250 grams, and a moment of inertia, Izz, about the center of gravity of the golf club head that exceeds 5000 grams-centimeters squared.

Yet another aspect of the present invention is a golf club having a length ranging from 42 inches to 44 inches and a moment of inertia, Izz, about the center of gravity of the golf club head that exceeds 5000 grams-centimeters squared. Yet another aspect of the present invention is a golf club head including a face component and an aft-body. The face component is composed of a first metal material and includes a striking plate portion and a return portion. The return portion extends rearward from a perimeter of the striking plate portion. The aft-body is coupled to the return portion of the face component. The aft-body is composed of a second material having a density less than that of the first material. The aft-body includes a crown portion and a sole portion having a bottom section and a ribbon section. The golf club head has a volume less than 470 cubic centimeters, a mass ranging from 210 grams to 250 grams, a moment of inertia about the Izz axis through the center of gravity of the golf club head greater than 5000 grams- centimeters squared, and a moment of inertia about the Ixx axis through the center of gravity of the golf club head greater than 3000 grams-centimeters squared.

Yet another aspect of the present invention is a golf club including a golf club head, a shaft and a grip. The golf club head has a volume ranging from 400 cubic centimeters to 470 cubic centimeters and a moment of inertia about the Izz axis through the center of gravity of the golf club head ranging from 4700 grams- centimeters squared to 6000 grams-centimeters squared. The shaft is connected to a heel end of the golf club head. The shaft has a mass ranging from 50 grams to 90 grams. The grip is disposed on a butt end of the shaft. The grip has a mass ranging from 30 grams to 50 grams. The golf club has an inertia ratio greater than 0.0020.

Yet another aspect of the present invention is a golf club including a golf club head, a shaft and a grip. The golf club head has a volume ranging from 400 cubic centimeters to 470 cubic centimeters and a moment of inertia about the Izz axis through the center of gravity of the golf club head ranging from 4700 grams- centimeters squared to 6000 grams-centimeters squared. The shaft is connected to a heel end of the golf club head. The shaft has a mass ranging from 50 grams to 90 grams. The grip is disposed on a butt end of the shaft. The grip has a mass ranging from 30 grams to 50 grams. The golf club has a length ranging from 42 inches to 44 inches. Yet another aspect of the present invention is a golf club head including a body comprising a crown, a sole, a ribbon and a striking plate. The golf club head has a volume less than 470 cubic centimeters, a mass ranging from 210 grams to 250 grams, a moment of inertia about the Izz axis through the center of gravity of the golf club head greater than 5000 grams-centimeters squared, and a moment of inertia about the Ixx axis through the center of gravity of the golf club head greater than 3000 grams- centimeters squared.

Brief Description of the Drawings

FIG. 1 is a perspective view of a club head of the present invention. FIG. IA is a front view of a golf club of the present invention.

FIG. 2 is a front view of the club head of FIG. 1. FIG. 3 is a heel side view of the club head of FIG. 1. FIG. 4 is a toe side view of the club head of FIG. 1. FIG. 5 is a rear plan view of the club head of FIG. 1. FIG. 6 is a top plan view of the club head of FIG. 1.

FIG. 7 is a bottom plan view of the club head of FIG. 1.

FIG. 8 is a top plan view of a golf club head illustrating the X-axis line and the Y-axis line through the center of gravity of the golf club head. FIG. 9 is a heel side view of a golf club head illustrating the X-axis line and the Z-axis line through the center of gravity of the golf club head.

FIG. 10 is a perspective view of a preferred embodiment of the club head of the present invention.

FIG. 11 is a front view of the club head of FIG. 10. FIG. 12 is a heel side view of the club head of FIG. 10.

FIG. 13 is a toe side view of the club head of FIG. 10.

FIG. 14 is a rear plan view of the club head of FIG. 10.

FIG. 15 is a top plan view of the club head of FIG. 10.

FIG. 16 is a bottom plan view of the club head of FIG. 10. FIG. 17 is a top plan view of a club head of the present invention illustrating the wall angles relative to each other.

FIG. 18 is a bottom plan view of a club head of the present invention illustrating the wall angles relative to each other.

FIG. 19 is a bottom plan view of a club head of the present invention illustrating the wall angles relative to each other.

FIG. 20 is a top plan view of a club head of the present invention illustrating the wall angles relative to each other.

FIG. 21 is a top plan view of a club head of the present invention illustrating the wall angles relative to each other. FIG. 22 is a front view of an alternative embodiment of a club head of the present invention.

FIG. 23 is a top plan view of the club head of FIG. 22.

FIG. 24 is a bottom plan view of the club head of FIG. 22.

FIG. 25 is a rear plan view of the club head of FIG. 22. FIG. 26 is a heel side view of the club head of FIG. 22.

FIG. 27 is a toe side view of the club head of FIG. 22.

FIG. 28 is an isolated interior view of a face component for a club head of the present invention. FIG. 29 is an isolated bottom plan view of a face component for a club head of the present invention.

FIG. 30 is an isolated toe side view of a face component for a club head of the present invention.

Best Mode(s) For Carrying Out The Invention

The present invention is generally directed at a golf club head that has a relatively high moment of inertia Izz about the center of gravity of the golf club head.

A general embodiment of the club head is illustrated in FIGS. 1-7. A preferred embodiment of the club head is illustrated in FIGS. 10-16. An alternative embodiment of the club head is illustrated in FIGS. 22-27. Those skilled in the pertinent art will recognize from this disclosure that other embodiments of the golf club head of the present invention are possible without departing from the scope and spirit of the present invention.

As shown in FIGS. 1-7, a golf club head of the present invention is generally designated 42. Preferably, a body 43 of the golf club head has a crown 62', a sole

64', a ribbon 90', and a striking plate 72', all of which preferably define a hollow interior. The golf club head 42 has a heel end 66, a toe end 68 an aft end 70.

The golf club head 42, when designed as a driver, preferably has a volume from 200 cubic centimeters to 600 cubic centimeters, more preferably from 300 cubic centimeters to 500 cubic centimeters, and most preferably from 400 cubic centimeters to 470 cubic centimeters, with a most preferred volume of approximately 460 cubic centimeters.

As shown in FIG. IA, a golf club 40 has a substantially square golf club head

42. Engaging the club head 42 is a shaft 48 that has a grip 50 at a butt end 52 of the shaft 48 and is inserted into a hosel 54 of the club head 42 at a tip end 56 of the shaft 48.

The golf club head 42 preferably has a mass of 210 to 250 grams. The golf club 40 preferably has a length, as measured from the top of a grip 50 to a sole of the club head 42, ranging from 42 inches to 44 inches. The grip 50 preferably has a mass ranging from 30 grams to 50 grams. The shaft 48 preferably has a mass ranging from 50 grams to 90 grams.

The club head 42 has a heel wall 166, a toe wall 168 and a rear wall 170 that are substantially straight relative to each other and the striking plate 72' of the club head 42.

As shown in FIG. 3, the heel wall 166 has a distance, "Dhw", from a perimeter 73 of the striking plate 72' to a furthest rearward extent of the club head 42 that preferably ranges from 2.00 to 5.00 inches, more preferably from 3.0 to 4.5 inches, and most preferably from 3.5 to 4.0 inches. As shown in FIG. 4, the toe wall 168 has a distance, "Dtw", from a perimeter

73 of the striking plate 72' to a furthest rearward extent of the club head 42 that preferably ranges from 2.00 to 5.00 inches, more preferably from 3.0 to 4.5 inches, and most preferably from 3.5 to 4.0 inches.

As shown in FIG. 5, the rear wall 170 has a distance, "Daw", from a widest extent of the heel end 66 of the club head to a widest extent of the toe end 68 of the club head 42 that preferably ranges from 2.50 to 5.50 inches, more preferably from 3.0 to 4.75 inches, and most preferably from 4.0 to 4.5 inches.

In one embodiment, the distances Dhw, Dtw and Daw are all equal in length ranging from 3.5 to 4.25 inches. In an alternative embodiment, the distances Dhw and Dtw are equal in length ranging from 2.5 to 4.0 inches.

As shown in FIG. 6, a geometric center of the club head 42 is designated "GC." The geometric center is defined as the center based on the geometry of the club head 42. A distance "Dgh" from the geometric center to an aft-heel edge point 150 ranges from 1.5 inches to 3.5 inches, and more preferably from 2.0 inches to 3.0 inches, and is most preferably 2.5 inches. A distance "Dgt" from the geometric center to an aft-toe edge point 155 ranges from 1.5 inches to 3.5 inches, and more preferably from 2.0 inches to 3.0 inches, and is most preferably 2.5 inches. In a preferred embodiment, the distances Dgh and Dgt are the farthest distances of any point on the club head 42 from the geometric center. In an alternative embodiment, the distances Dgh and Dgt are at least equal to the farthest distances of any point on the club head 42 from the geometric center. The aft-heel edge point 150 is defined as the inflection point along the edge of the heel wall 166 and the rear wall 170 wherein the heel wall 166 transitions to the rear wall 170. The aft-toe edge point 155 is defined as the inflection point along the edge of the toe wall 168 and the rear wall 170 wherein the toe wall 168 transitions to the rear wall 170.

As shown in FIG. 6, the club head 42 has an aft-heel curvature section 200 and an aft-toe curvature section 205. The aft-heel curvature section 200 is the transition from the heel wall 166 to the rear wall 170. The aft-toe curvature section 205 is the transition from the toe wall 168 to the rear wall 170. The club head 42 of the present invention has a reduced curvature section as compared to club head 42x of the prior art.

As shown in FIG. 7, the heel wall 166 has a distance, "Dhw' ", from a perimeter 73 of the striking plate 72' to the aft-heel edge point 150 that preferably ranges from 2.00 to 4.5 inches, more preferably from 2.5 to 4.25 inches, and most preferably from 3.0 to 4.0 inches.

As shown in FIG. 7, the toe wall 168 has a distance, "Dtw' ", from a perimeter 73 of the striking plate 72' to the aft-toe edge point 155 that preferably ranges from 2.00 to 4.5 inches, more preferably from 2.5 to 4.25 inches, and most preferably from 3.0 to 4.0 inches.

As shown in FIG. 7, the rear wall 170 has a distance, "Daw' ", from the aft- heel edge point 150 to the aft-toe edge point 155 that preferably ranges from 2.50 to 5.00 inches, more preferably from 3.0 to 4.0 inches, and most preferably from 3.25 to 3.75 inches. In a preferred embodiment, the distances Dhw' and Dtw' are equal in length ranging from 2.5 to 4.0 inches.

In a preferred embodiment, the club head 42 is generally composed of two components, a face component 60, and an aft-body 61, as shown in FIGS. 10-16. The aft-body 61 preferably has a crown portion 62 and a sole portion 64. The face component 60 is generally composed of a single piece of metal, and is preferably composed of a forged metal material. More preferably, the forged metal material is a forged titanium material. Such titanium materials include pure titanium and titanium alloys such as 6-4 titanium alloy, SP-700 titanium alloy (available from Nippon Steel of Tokyo, Japan), DAT 55G titanium alloy available from Diado Steel of Tokyo, Japan, Ti 10-2-3 Beta-C titanium alloy available from RTI International Metals of Ohio, and the like. Other metals for the face component 60 include stainless steel, other high strength steel alloy metals and amorphous metals. Alternatively, the face component 60 is manufactured through casting, forming, machining, powdered metal forming, metal-injection-molding, electro chemical milling, and the like.

The face component 60 generally includes a striking plate portion (also referred to herein as a face plate) 72 and a return portion 74 extending laterally inward from a perimeter 73 of the striking plate portion 72. The striking plate portion 72 typically has a plurality of scorelines 75 thereon. The striking plate portion 72 preferably has a thickness ranging from 0.010 inch to 0.250 inch, and the return portion 74 preferably has a thickness ranging from 0.010 inch to 0.250 inch. The return portion 74 preferably extends a distance ranging from 0.25 inch to 1.5 inches from the perimeter 73 of the striking plate portion 72.

In a preferred embodiment, the return portion 74 generally includes an upper lateral section 76, a lower lateral section 78, a heel lateral section 80 and a toe lateral section 82. Thus, the return 74 preferably encircles the striking plate portion 72 a full 360 degrees. However, those skilled in the pertinent art will recognize that the return portion 74 may only encompass a partial section of the striking plate portion 72, such as 270 degrees or 180 degrees, and may also be discontinuous. The upper lateral section 76 preferably extends inward, towards the aft-body 61, a predetermined distance, d, to engage the crown 62. In a preferred embodiment, the predetermined distance ranges from 0.2 inch to 1.2 inch, more preferably 0.40 inch to 1.0 inch, and most preferably 0.8 inch, as measured from the perimeter 73 of the striking plate portion 72 to the rearward edge of the upper lateral section 76. In a preferred embodiment, the upper lateral section 76 is substantially straight and substantially parallel to the striking plate portion 72 from the heel end 66 to the toe end 68.

The perimeter 73 of the striking plate portion 72 is preferably defined as the transition point where the face component 60 transitions from a plane substantially parallel to the striking plate portion 72 to a plane substantially perpendicular to the striking plate portion 72. Alternatively, one method for determining the transition point is to take a plane parallel to the striking plate portion 72 and a plane perpendicular to the striking plate portion, and then take a plane at an angle of forty- five degrees to the parallel plane and the perpendicular plane. Where the forty-five degrees plane contacts the face component is the transition point thereby defining the perimeter of the striking plate portion 72.

The heel lateral section 80 is substantially perpendicular to the striking plate portion 72, and the heel lateral section 80 preferably covers a portion of the hosel 54 before engaging an optional ribbon section 90 and a bottom section 91 of the sole portion 64 of the aft-body 61. The heel lateral section 80 is attached to the sole portion 64, both the ribbon section 90 and the bottom section 91, as explained in greater detail below. The heel lateral section 80 extends inward a distance, d, from the perimeter 73 a distance of 0.2 inch to 1.2 inch, more preferably 0.40 inch to 1.0 inch, and most preferably 0.8 inch. The heel lateral section 80 is preferably straight at its edge.

At the other end of the face component 60 is the toe lateral section 82. The toe lateral section 82 is preferably attached to the sole 64, both the ribbon 90 and the bottom section 91, as explained in greater detail below. The toe lateral section 82 extends inward a distance, d, from the perimeter 73 a distance of 0.2 inch to 1.2 inch, more preferably 0.40 inch to 1.0 inch, and most preferably 0.8 inch. The toe lateral section 82 preferably is preferably straight at its edge.

The lower lateral section 78 extends inward, toward the aft-body 61, a distance, d, to engage the sole portion 64. In a preferred embodiment, the distance d ranges from 0.2 inch to 1.2 inch, more preferably 0.40 inch to 1.0 inch, and most preferably 0.8 inch, as measured from the perimeter 73 of the striking plate portion 72 to the edge of the lower lateral section 78.

The aft-body 61 is preferably composed of a non-metal material, preferably a composite material such as continuous fiber pre-preg material (including thermosetting materials or a thermoplastic materials for the resin). Other materials for the aft-body 61 include other thermosetting materials or other thermoplastic materials such as injectable plastics. Alternatively, the aft-body 61 is composed of low-density metal materials, such as magnesium or aluminum. Exemplary magnesium alloys are available from Phillips Plastics Corporation under the brands AZ-91 -D (nominal composition of magnesium with aluminum, zinc and manganese), AM-60-B (nominal composition of magnesium with aluminum and manganese) and AM-50-A (nominal composition of magnesium with aluminum and manganese). The aft-body 61 is preferably manufactured through metal-injection-molding. Alternatively, the aft-body 61 is manufactured through casting, forming, machining, powdered metal forming, electro chemical milling, and the like.

The aft-body 61 is preferably manufactured through bladder-molding, resin transfer molding, resin infusion, injection molding, compression molding, or a similar process. In a preferred process, the face component 60, with an adhesive on the interior surface of the return portion 74, is placed within a mold with a preform of the aft-body 61 for bladder molding. Such adhesives include thermosetting adhesives in a liquid or a film medium. A preferred adhesive is a two part liquid epoxy sold by 3 M of Minneapolis Minnesota under the brand names DP420NS and DP460NS. Other alternative adhesives include modified acrylic liquid adhesives such as DP810NS, also sold by the 3 M company. Alternatively, foam tapes such as Hysol Synspan may be utilized with the present invention.

A bladder is placed within the hollow interior of the preform and face component 60, and is pressurized within the mold, which is also subject to heating. The co-molding process secures the aft-body 61 to the face component 60.

Alternatively, the aft-body 61 is bonded to the face component 60 using an adhesive, or mechanically secured to the return portion 74.

The crown portion 62 of the aft-body 61 is generally convex toward the sole 64, and engages the ribbon section 90 of sole portion 64 outside of the engagement with the face member 60. The crown portion 62 preferably has a thickness in the range of 0.010 to 0.100 inch, more preferably in the range of 0.025 inch to 0.070 inch, even more preferably in the range of 0.028 inch to 0.040 inch, and most preferably has a thickness of 0.033 inch. The sole portion 64, including the bottom section 91 and the optional ribbon section 90, which is substantially perpendicular to the bottom section 91, preferably has a thickness in the range of 0.010 to 0.100 inch, more preferably in the range of 0.025 inch to 0.070 inch, even more preferably in the range of 0.028 inch to 0.040 inch, and most preferably has a thickness of 0.033 inch, hi a preferred embodiment, the aft-body 61 is composed of a plurality of plies of pre-preg, typically six or seven plies. The hosel 54 is preferably at least partially disposed within the hollow interior of the club head 42, and is preferably located as a part of the face component 60. The hosel 54 is preferably composed of a similar material to the face component 60, and is preferably secured to the face component 60 through welding or the like. Alternatively, the hosel 54 may be formed with the formation of the face component 60. hi a preferred embodiment, a weight member 122 is preferably positioned on the aft body 61 to increase the moment of inertia of the club head 42, to influence the center of gravity, or influence other inherent properties of the golf club head 42. The weight member 122 is preferably composed of tungsten loaded film, tungsten doped polymers, or similar weighting mechanisms. Those skilled in the pertinent art will recognize that other high density materials, such as lead-free pewter, may be utilized as an optional weight without departing from the scope and spirit of the present invention. In a preferred embodiment two weight members 122a and 122b are embedded within the plies of pre-preg of the ribbon section 90 of the sole portion 64 of the aft- body 61. Individually, each of weight 122 has a mass ranging from 5 grams to 30 grams. Each weight 122 is preferably composed of a material that has a density ranging from 5 grams per cubic centimeters to 20 grams per cubic centimeters, more preferably from 7 grams per cubic centimeters to 12 grams per cubic centimeters.

Each weight 122 is preferably composed of a polymer material integrated with a metal material. The metal material is preferably selected from copper, tungsten, steel, aluminum, tin, silver, gold, platinum, or the like. A preferred metal is tungsten due to its high density. The polymer material is a thermoplastic or thermosetting polymer material. A preferred polymer material is polyurethane, epoxy, nylon, polyester, or similar materials. A most preferred polymer material is a thermoplastic polyurethane. A preferred weight 122 is an injection molded thermoplastic polyurethane integrated with tungsten to have a density of 8.0 grams per cubic centimeters. In a preferred embodiment, each weight 122 is composed of from 50 to 95 volume percent polyurethane and from 50 to 5 volume percent tungsten. Also, in a preferred embodiment, each weight 122 is composed of from 10 to 25 weight percent polyurethane and from 90 to 75 weight percent tungsten.

Preferably, the weights 122a-b are positioned in the aft-heel corner and the aft- toe corner of the golf club head 42 generally corresponding to the aft-heel edge point 150 and the aft-toe edge point 155. Those skilled in the pertinent art will recognize that other weighting materials may be utilized for the weight 122 without departing from the scope and spirit of the present invention. The placement of the weights 122 allows for the moment of inertia of the golf club head 42 to be optimized.

As shown in FIGS. 28-30, the face component preferably has a striking plate portion 72 with varying thickness wherein portion 72a is thicker than 72b which is thicker than 72c. In a preferred embodiment, the striking plate portion 72 has a varying thickness. Alternatively, the striking plate portion 72 has a uniform thickness. As mentioned previously, the face component 60 is preferably forged from a rod of metal material. Alternatively, the face component 60 is cast from molten metal in a method such as the well-known lost-wax casting method. The metal for forging or casting is preferably titanium or a titanium alloy such as 6-4 titanium alloy, alpha-beta titanium alloy or beta titanium alloy for forging, and 6-4 titanium for casting.

Additional methods for manufacturing the face component 60 include forming the face component 60 from a flat sheet of metal, super-plastic forming the face component 60 from a flat sheet of metal, machining the face component 60 from a solid block of metal, electrochemical milling the face from a forged pre-form, and like manufacturing methods. Yet further methods include diffusion bonding titanium sheets to yield a variable face thickness face and then superplastic forming. Alternatively, the face component 60 is composed of an amorphous metal material.

Yet another embodiment of the golf club head 42 shown in FIGS. 1-7, the body 43 is preferably composed of a metal material such as titanium, titanium alloy, or the like, and is most preferably composed of a cast titanium alloy material. The body 43 is preferably cast from molten metal in a method such as the well-known lost-wax casting method. The metal for casting is preferably titanium or a titanium alloy such as 6-4 titanium alloy, alpha-beta titanium alloy or beta titanium alloy for forging, and 6-4 titanium for casting. Alternatively, the body 43 is composed of 17-4 steel alloy. Additional methods for manufacturing the body 43 include forming the body 43 from a flat sheet of metal, super-plastic forming the body 43 from a flat sheet of metal, machining the body 43 from a solid block of metal, electrochemical milling the body from a forged pre-form, casting the body using centrifugal casting, casting the body using levitation casting, and like manufacturing methods. The golf club head 42 of this embodiment optionally has a front wall with an opening for placement of a striking plate insert 72'. The striking plate insert 72' preferably is composed of a formed titanium alloy material. Such titanium materials include titanium alloys such as 6-22-22 titanium alloy and Ti 10-2-3 alloy, Beta-C titanium alloy, all available from RTI International Metals of Ohio, SP-700 titanium alloy (available from Nippon Steel of Tokyo, Japan), DAT 55G titanium alloy available from Diado Steel of Tokyo, Japan, and like materials. The preferred material for the striking plate insert 72' is a heat treated 6-22-22 titanium alloy which is a titanium alloy composed by weight of titanium, 6% aluminum, 2% tin, 2% chromium, 2% molybdenum, 2% zirconium and 0.23% silicon. The titanium alloy will have an alpha phase in excess of 40% of the overall microstructure.

In a preferred embodiment, the striking plate insert 72' has uniform thickness that ranges from 0.040 inch to 0.250 inch, more preferably a thickness of 0.080 inch to 0.120 inch, and is most preferably 0.108 inch for a titanium alloy striking plate insert 72'.

In yet another embodiment for the golf club head 42 shown in FIGS. 1-7, the golf club head has a construction with a crown composed of plies of pre-preg material.

In yet another embodiment, the golf club head 42 has a shape as disclosed, particularly as shown in FIGS.1-7, and a construction with a body composed of plies of pre-preg material. hi a preferred embodiment, the golf club head 42 has a high coefficient of restitution thereby enabling for greater distance of a golf ball hit with the golf club 40. The coefficient of restitution (also referred to herein as "COR") is determined by the following equation:

U₁ -U₂

wherein U] is the club head velocity prior to impact; CT₂ is the golf ball velocity prior to impact which is zero; v_/ is the club head velocity just after separation of the golf ball from the face of the club head; v₂ is the golf ball velocity just after separation of the golf ball from the face of the club head; and e is the coefficient of restitution between the golf ball and the club face.

The values of e are limited between zero and 1.0 for systems with no energy addition. The coefficient of restitution, e, for a material such as a soft clay or putty would be near zero, while for a perfectly elastic material, where no energy is lost as a result of deformation, the value of e would be 1.0. The present invention provides a club head having a coefficient of restitution ranging from 0.81 to 0.94, as measured under conventional test conditions. The coefficient of restitution of the club head 42 under standard USGA test conditions with a given ball ranges from approximately 0.81 to 0.94, preferably ranges from 0.825 to 0.883 and is most preferably 0.845.

Additionally, the striking plate portion 72 of the face component 60 has a more rectangular face providing a greater aspect ratio. The aspect ratio as used herein is defined as the width, "W", of the face divided by the height, "H", of the face. In one preferred embodiment, the width W is 100 millimeters and the height H is 56 millimeters giving an aspect ratio of 1.8. The striking plate portion 72 of the present invention preferably has an aspect ratio that is greater than 1.8 for a club head having a volume greater than 420 cubic centimeters. The face area of the striking plate portion 72 preferably ranges from 5.00 square inches to 10.0 square inches, more preferably from 6.0 square inches to 9.5 square inches, and most preferably from 7.0 square inches to 9.0 square inches.

FIGS. 8 and 9 illustrate the axes of inertia through the center of gravity of the golf club head. The axes of inertia are designated X, Y and Z. The X-axis extends from the striking plate portion 72 through the center of gravity, CG, and to the rear of the golf club head 42. The Y-axis extends from the toe end 68 of the golf club head 42 through the center of gravity, CG, and to the heel end 66 of the golf club head 42. The Z-axis extends from the crown portion 62 through the center of gravity, CG, and through the sole portion 64. The center of gravity and the moment of inertia of a golf club head 42 are preferably measured using a test frame (X^τ, Y^τ, Z^τ), and then transformed to a head frame (X^H, Y^H, Z^H). The center of gravity of a golf club head may be obtained using a center of gravity table having two weight scales thereon. If a shaft is present, it is removed and replaced with a hosel cube that has a multitude of faces normal to the axes of the golf club head. Given the weight of the golf club head, the scales allow one to determine the weight distribution of the golf club head when the golf club head is placed on both scales simultaneously and weighed along a particular direction, the X, Y or Z direction. Those skilled in the pertinent art will recognize other methods to determine the center of gravity and moments of inertia of a golf club head.

In general, the moment of inertia, Izz, about the Z axis for the golf club head 42 of the present invention will range from 4500g-cm² to 6000g-cm², preferably from 5000g-cm² to 5500g-cm², and most preferably 5000g-cm². The moment of inertia, Iyy, about the Y axis for the golf club head 42 of the present invention will range from 2000g-cm² to 4000g-cm², preferably from 2500g-cm² to 3500g-cm², and most preferably from 2900g-cm² to 3300g-cm². The moment of inertia, Ixx, about the X axis for the golf club head 42 of the present invention will range from 2000g-cm² to 4000g-cm², preferably from 2500g-cm² to 3750g-cm², and most preferably from 3000g-cm² to 3500g-cm². In general, the golf club head 42 has products of inertia such as disclosed in

U.S. Patent Number 6,425,832, which was filed on July 26, 2001 and is hereby incorporated by reference in its entirety. Preferably, each of the products of inertia, Ixy, Ixz and Iyz, of the golf club head 42 have an absolute value less than 100 grams- centimeter squared. Alternatively, at least two of the products of inertia, Ixy, Ixz or Iyz, of the golf club head 42 have an absolute value less than 100 grams-centimeter squared.

FIGS. 17-21 illustrate the substantial straightness of the heel wall 166, the toe wall 168 and the rear wall 170 of the club head 42. In a preferred embodiment, at least 50% of the length of the heel wall 166 extends rearward from the perimeter 73 of the striking plate portion 72 within an angle of 80 degrees to 90 degrees relative to a plane parallel to the farthest extent of the striking plate portion 72. For example, in FIG. 18, line 502 represents a plane parallel to the farthest extent of the striking plate portion 72 and line 503 is at an angle of 90 degrees relative to line 502. Shown in a dashed line is a line at 80 degrees relative to line 502. In a more preferred embodiment, at least 66% of the length of the heel wall 166 extends rearward from the perimeter 73 of the striking plate portion 72 within an angle of 80 degrees to 90 degrees relative to a plane parallel to the farthest extent of the striking plate portion 72. In yet an even more preferred embodiment, at least 75% of the length of the heel wall 166 extends rearward from the perimeter 73 of the striking plate portion 72 within an angle of 80 degrees to 90 degrees relative to a plane parallel to the farthest extent of the striking plate portion 72. In yet a further more preferred embodiment, at least 90% of the length or even at least 95% of the length of the heel wall 166 extends rearward from the perimeter 73 of the striking plate portion 72 within an angle of 80 degrees to 90 degrees relative to a plane parallel to the farthest extent of the striking plate portion 72. Further, 50% to 95% of the length of the heel wall 166 preferably extends rearward from the perimeter 73 of the striking plate portion 72 within an angle of 80 degrees to 90 degrees relative to a plane parallel to the farthest extent of the striking plate portion 72, more preferably 66% to 80%. In a preferred embodiment, at least 50% of the length of the toe wall 168 extends rearward from the perimeter 73 of the striking plate portion 72 within an angle of 80 degrees to 90 degrees relative to a plane parallel to the farthest extent of the striking plate portion 72. For example, in FIG. 20, line 504 represents a plane parallel to the farthest extent of the striking plate portion 72 and line 504 is at an angle of 90 degrees relative to line 504. Shown in a dashed line is a line at 80 degrees relative to line 502. In a more preferred embodiment, at least 66% of the length of the toe wall 168 extends rearward from the perimeter 73 of the striking plate portion 72 within an angle of 80 degrees to 90 degrees relative to a plane parallel to the farthest extent of the striking plate portion 72. In yet an even more preferred embodiment, at least 75% of the length of the toe wall 168 extends rearward from the perimeter 73 of the striking plate portion 72 within an angle of 80 degrees to 90 degrees relative to a plane parallel to the farthest extent of the striking plate portion 72. In yet a further more preferred embodiment, at least 90% of the length or even at least 95% of the length of the toe wall 168 extends rearward from the perimeter 73 of the striking plate portion 72 within an angle of 80 degrees to 90 degrees relative to a plane parallel to the farthest extent of the striking plate portion 72. Further, 50% to 95% of the length of the toe wall 168 preferably extends rearward from the perimeter 73 of the striking plate portion 72 within an angle of 80 degrees to 90 degrees relative to a plane parallel to the farthest extent of the striking plate portion 72, more preferably 66% to 80%.

In a preferred embodiment, at least 50% of the length of the rear wall 170 extends substantially parallel with a farthest extent of the striking plate portion 72 within an angle of 80 degrees to 90 degrees relative to a plane parallel to the farthest extent of the heel wall 166. For example, in FIG. 17, line 501 represents a plane parallel to the farthest extent of the heel wall 166 and line 500 is at an angle of 90 degrees relative to line 501. Shown in a dashed line is a line at 80 degrees relative to line 501 and a line at 60 degrees relative to line 501. In a more preferred embodiment, at least 66% of the length of the rear wall 170 extends substantially parallel with a farthest extent of the striking plate portion 72 within an angle of 80 degrees to 90 degrees relative to a plane parallel to the farthest extent of the heel wall 166. In yet an even more preferred embodiment, at least 75% of the length of the rear wall 170 extends substantially parallel with a farthest extent of the striking plate portion 72 within an angle of 80 degrees to 90 degrees relative to a plane parallel to the farthest extent of the heel wall 166. In yet a further more preferred embodiment, at least 90% of the length of the heel wall 170 extends substantially parallel with a farthest extent of the striking plate portion 72 within an angle of 80 degrees to 90 degrees relative to a plane parallel to the farthest extent of the heel wall 166. Further, 50% to 95% of the length of the rear wall 170 preferably extends substantially parallel with a farthest extent of the striking plate portion 72 within an angle of 80 degrees to 90 degrees relative to a plane parallel to the farthest extent of the heel wall 166, more preferably 66% to 80 %.

As shown in FIG. 21, a distance "Dmh" from the center of gravity, CG, of the club head 42 to an aft-heel edge point 150 ranges from 1.0 inches to 3.5 inches, and more preferably from 2.0 inches to 3.0 inches, and is most preferably 2.25 inches. A distance "Dmt" from the geometric center to an aft-toe edge point 155 ranges from 1.75 inches to 4.0 inches, and more preferably from 2.5 inches to 3.75 inches, and is most preferably 3.25 inches. In a preferred embodiment, the distance Dmt is the farthest distance of any point on the club head 42 from the center of gravity of the club head 42. Further, with a weighting member 122b positioned at about aft-toe edge point 155, the weighting member 122b represents the greatest mass in the least volume the farthest away from the center of gravity of the club head 42.

TABLE ONE

Table One illustrates the mass properties of current drivers as compared to the golf clubs of the present invention, Example 1 and Example 2. Each of the current drivers had a grip with a mass of 51 grams and a shaft with a mass of 60 grams. Both Example 1 and Example 2 had a grip mass of 51 grams and a shaft mass of 60 grams. The loft angle of the club of Example 1 was 12 degrees and the loft angle of the club of Example 2 was 13 degrees. The club length of the club of the present invention is less than the normal club length.

The inertia ratio is Izz of the club head divided by the Club Iyy. The Izz of the club head is defined as the moment of inertia about the Z axis through the center of gravity of the golf club head, which gives a measure of the club head's resistance to twisting in the face open/close direction. The club Iyy is the moment of inertia of the entire club taken at the butt end of the shaft, which is calculated by taking the sum of the moment of inertia of the individual components of the club taken about the Y axis as shown in FIG. IA. All of the current drivers listed in Table One have an inertia ratio less than or equal to 0.0018. The clubs of the present invention have an inertia ratio greater than 0.0019, more preferably greater than 0.0020, even more preferably greater than 0.0021, and most preferably 0.00230 or greater.

Claims

Claims 1. A golf club comprising: a golf club head having a volume ranging from 400 cubic centimeters to 470 cubic centimeters, a mass ranging from 210 grams to 250 grams, and a moment of inertia about the Izz axis through the center of gravity of the golf club head ranging from 4700 grams-centimeters squared to 6000 grams-centimeters squared; a shaft connected to a heel end of the golf club head, the shaft having a mass ranging from 50 grams to 90 grams; and a grip disposed on a butt end of the shaft, the grip having a mass ranging from 30 grams to 50 grams; wherein the golf club has a length ranging from 42 inches to 44 inches.

2. The golf club according to claim 1 wherein the golf club head has a moment of inertia about the Izz axis through the center of gravity of the golf club head ranging 4900 grams-centimeters squared to 6000 grams-centimeters squared.

3. The golf club according to claim 1 wherein the golf club head has a moment of inertia about the Izz axis through the center of gravity of the golf club head ranging 5000 grams-centimeters squared to 6000 grams-centimeters squared.

4. The golf club according to claim 1 wherein the golf club head has a mass of 220 grams to 250 grams.

5. The golf club according to claim 1 wherein the golf club head comprises: a face component composed of a first material, the face component comprising a striking plate portion and a return portion, the return portion extending a distance ranging from 0.25 inch to 1.5 inches from a perimeter of the striking plate portion; and a substantially square aft-body coupled to the return portion of the face component, the aft-body composed of a second material having a density less than that of the first material, the aft-body comprising a crown portion, a sole portion, the sole portion having a bottom section and a ribbon section, the ribbon section being located between the crown portion and the bottom section of the sole portion;

wherein the golf club head is substantially square.

6. The golf club according to claim 1 wherein a ratio of the moment of inertia about the Izz axis through the center of gravity of the golf club head divided by the length of the club is greater than 47 grams-centimeter.

7. The golf club according to claim 1 wherein a ratio of the moment of inertia about the Izz axis through the center of gravity of the golf club head divided by the mass of the club head is greater than 24.5 centimeters squared.

8. The golf club according to claim 1 wherein the golf club has an inertia ratio greater than 0.0019.

9. The golf club according to claim 1 wherein the golf club has an inertia ratio greater than 0.0022.

10. A golf club comprising: a golf club head having a volume ranging from 400 cubic centimeters to 470 cubic centimeters and a moment of inertia about the Izz axis through the center of gravity of the golf club head ranging from 4700 grams-centimeters squared to 6000 grams-centimeters squared; a shaft connected to a heel end of the golf club head, the shaft having a mass ranging from 50 grams to 90 grams; and a grip disposed on a butt end of the shaft, the grip having a mass ranging from 30 grams to 50 grams; wherein the golf club has an inertia ratio greater than 0.0020.

11. The golf club according to claim 10 wherein the golf club head 4900 grams- centimeters squared to 6000 grams-centimeters squared.

12. The golf club according to claim 10 wherein the golf club has an inertia ratio greater than 0.0022.

13. The golf club according to claim 10 wherein the golf club head has a mass of 220 grams to 250 grams.

14. The golf club according to claim 10 wherein the golf club head comprises: a face component composed of a first material, the face component comprising a striking plate portion and a return portion, the return portion extending a distance ranging from 0.25 inch to 1.5 inches from a perimeter of the striking plate portion; and a substantially square aft-body coupled to the return portion of the face component, the aft-body composed of a second material having a density less than that of the first material, the aft-body comprising a crown portion, a sole portion, the sole portion having a bottom section and a ribbon section, the ribbon section being located between the crown portion and the bottom section of the sole portion;

wherein the golf club head is substantially square.

15. A golf club head comprising: a face component composed of a first material, the face component comprising a striking plate portion and a return portion, the return portion extending a distance ranging from 0.25 inch to 1.5 inches from a perimeter of the striking plate portion; and a substantially square aft-body coupled to the return portion of the face component, the aft-body composed of a second material having a density less than that of the first material, the aft-body comprising a crown portion, a sole portion, the sole portion having a bottom section and a ribbon section, the ribbon section being located between the crown portion and the bottom section of the sole portion;

wherein the golf club head has a volume ranging from 400 cubic centimeters to 470 cubic centimeters, a mass ranging from 210 grams to 250 grams, and a moment of inertia about the Izz axis through the center of gravity of the golf club head ranging from 4700 grams-centimeters squared to 6000 grams-centimeters squared.

16. A golf club head comprising: a body comprising a crown, a sole, a ribbon and a striking plate; wherein the golf club head has a volume less than 470 cubic centimeters, a mass ranging from 210 grams to 250 grams, a moment of inertia about the Izz axis through the center of gravity of the golf club head greater than 5000 grams-centimeters squared, and a moment of inertia about the Ixx axis through the center of gravity of the golf club head greater than 3000 grams-centimeters squared.

17. A golf club head comprising: a face component composed of a first metal material, the face component comprising a striking plate portion and a return portion, the return portion extending rearward from a perimeter of the striking plate portion; and an aft-body coupled to the return portion of the face component, the aft-body composed of a second material having a density less than that of the first material, the aft-body comprising a crown portion, a sole portion, the sole portion having a bottom section and a ribbon section;

wherein the golf club head has a volume less than 470 cubic centimeters, a mass ranging from 210 grams to 250 grams, a moment of inertia about the Izz axis through the center of gravity of the golf club head greater than 5000 grams- centimeters squared, and a moment of inertia about the Lex axis through the center of gravity of the golf club head greater than 3000 grams-centimeters squared.