Multi-stage forging process

Abstract

An iron-type golf club head having a cavity formed via a multi-stage forging process. The forged iron-type golf club head is formed from a single billet of material. An intermediate step of the multi-stage forging process forms a cavity in the iron-type golf club head capable of receiving an insert. The resulting iron-type golf club head has a substantially lower center of gravity and a higher moment of inertia compared to a conventional forged iron-type golf club head lacking a cavity. Additionally, the resulting iron-type golf club head has a firmer feel than a conventional cast iron-type golf club head as a result of the tighter grain structure provided by the forging process.

Description

[Technical field]

[0001] (Cross-reference priority) This claims the benefit of U.S. Provisional Application No. 63 / 363,780, filed April 28, 2022, U.S. Provisional Application No. 63 / 364,949, filed May 18, 2022, U.S. Provisional Application No. 63 / 373,831, filed August 29, 2022, U.S. Provisional Application No. 63 / 378,811, filed October 7, 2022, U.S. Provisional Application No. 63 / 269,232, filed March 11, 2022, and U.S. Patent Application No. 17 / 659,232, filed March 11, 2022, the contents of which are incorporated by reference in their entireties herein.

[0002] FIELD OF THE DISCLOSURE This disclosure relates generally to golf clubs, and more particularly to a method of making a forged iron having a cavity. [Background technology]

[0003] In general, iron-type golf club heads can be manufactured by various methods such as casting, co-casting, metal injection molding, machine cutting, and forging. Many iron-type golf club heads include cavities or fill features to adjust the performance characteristics of the golf club head when the golf club head strikes a golf ball. Often, irons that include cavities are cast or co-cast to obtain these advanced geometries. Cutting techniques are used to make club heads with cavities from a single block of material, which is an expensive and time-consuming process. Forging techniques are often used to make iron golf club heads that are formed from a monolithic block of material. Forging is cheaper and faster than cutting. However, forging geometries are limited, especially in the variations of cavity design and face plate. With current industrial technology, it is difficult to quickly and inexpensively make forged iron-type club heads with any type of cavity. There is a need in the art for forged golf club heads with cavities. [Brief description of the drawings]

[0004] To facilitate further explanation of the embodiments, the following drawings are provided:

[0005] [Figure 1] 1 illustrates a flow diagram of one embodiment in which an exemplary golf club head may be manufactured.

[0006] [Diagram 2] 3A-3C show cross-sectional views of a club head during a multi-stage forging process.

[0007] [Diagram 3] 3A-3C show cross-sectional views of a club head during a multi-stage forging process.

[0008] [Figure 4] 3A-3C show cross-sectional views of a club head during a multi-stage forging process.

[0009] [Diagram 5] 1 shows a manufactured golf club head having a cavity.

[0010] [Figure 6] 1 illustrates a rear perspective view of a manufactured golf club head having a cavity according to a first embodiment.

[0011] [Figure 7] 7 shows a cross-sectional view of the golf club head of FIG. 6.

[0012] [Figure 8] FIG. 7 is a front view of the golf club head of FIG. 6.

[0013] [Figure 9] FIG. 7 shows a toe side view of the golf club head of FIG. 6.

[0014] [Figure 10] 13 illustrates a rear view of a manufactured golf club head having a cavity according to a second embodiment.

[0015] [Figure 11] 11 shows a cross-sectional view of the golf club head of FIG. 10.

[0016] [Figure 12] 11 shows a rear perspective view of the golf club head of FIG. 10.

[0017] [Figure 13] 1 illustrates a comparison of an exemplary club head and a control club head.

[0018] [Figure 14] 1 illustrates a flow diagram of one embodiment in which an exemplary golf club head may be manufactured.

[0019] [Figure 15] 13 shows a cross-sectional view of a manufactured golf club head having a cavity according to a third embodiment.

[0020] [Figure 16] 16 shows a cross-sectional view of the club head of FIG. 15.

[0021] [Figure 17] 16 shows a cross-sectional view of the club head of FIG. 15.

[0022] [Figure 18] FIG. 13 shows a front view of a manufactured golf club head according to a fourth embodiment.

[0023] [Figure 19] 19 shows a rear view of the club head of FIG. 18.

[0024] [Figure 20] 19 shows a toe diagram of the club head of FIG. 18. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Other aspects of the disclosure will become apparent by consideration of the detailed description and accompanying drawings.

[0026] For simplicity and clarity of explanation, the drawings show schematic configuration methods, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the present disclosure. Furthermore, elements in the drawings are not necessarily drawn to scale. For example, the dimensions of some elements in the drawings may be exaggerated relative to other elements to help understand the embodiments of the present disclosure. The same reference numbers in different drawings refer to the same elements.

[0027] Described herein is a forged iron-type golf club head with a rear cavity that is manufactured through a multi-stage forging process. The forged iron-type golf club head is formed from a single billet of material and has a rear cavity configured to receive an elastomeric insert. The rear cavity is formed through an intermediate forging process. The forged iron-type golf club head with a rear cavity has a substantially lower center of gravity and a higher moment of inertia compared to a conventional forged iron due to the use of an elastomeric insert. The elastomeric insert and cavity conserve mass that can be redistributed to other portions of the club head to lower the center of gravity and increase the moment of inertia. The forged iron also has a tighter grain structure, resulting in a more solid feeling iron that is characteristic of forged clubs.

[0028] The forged iron type golf club head with a rear cavity can further have various shapes to improve manufacturability and tailor mass properties. In some embodiments, the rear forging cavity can have a narrow and deep cavity to improve deflection of the striking face. In other embodiments, the forging cavity can have a shallow and wide cavity to improve manufacturability. In other embodiments, the forged iron type golf club head can have various thicknesses in different regions of the striking face, such as the top region, middle region, or lower region, to improve striking face bending during the rough forging process described above. The rear wall of the forged iron type golf club head has a sufficiently large surface area and angle to improve the effective angle so that the hot press tool has sufficient clearance to form the cavity.

[0029] Forged iron-type golf clubs are manufactured by a multi-stage forging process. The process includes rough forging a solid block billet of a suitable metal to form an intermediate club head body, machining the rough dimensions of a cavity in the club head, hot pressing the machined cavity to form the final cavity with precise dimensions, precision forging the intermediate club head to finalize the cavity, precision molding the golf club head body to form the final detail and texture, and installing an insert within the cavity. The intermediate club head formed by rough forging has a curved striking face that allows the cavity to be formed in the rear body by hot pressing. The temporarily curved striking face allows the cavity to be formed by providing a forging path that would otherwise be blocked by the striking face. The curved striking face of the intermediate club head is then precision forged back to a flat striking face to form the final manufactured golf club head. This curved striking face technology allows manufacturers to create forged golf club head bodies with deep undercut cavities from a single solid billet because the curved striking face provides space for hot pressing the cavities.

[0030] (definition) It should be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments described herein can, for example, operate in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprise" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions, and a process, method, system, article, device, or apparatus that comprises a list of elements is not necessarily limited to those elements, but can include other elements not expressly listed or inherent to such process, method, system, article, device, or apparatus.

[0031] Terms such as "left," "right," "front," "rear," "top," "bottom," "upper," and "lower" in the detailed description and claims, where applicable, are used for descriptive purposes and not necessarily to describe permanent relative locations. It should be understood that such terms are interchangeable under appropriate circumstances, such that the embodiments of the invention described herein are capable of operation in other orientations than those illustrated or otherwise described herein, for example. Additionally, the term "rough forging" describes a forging technique in which a block-shaped billet is rapidly formed into the general desired shape with minimal tooling or machining.

[0032] As used herein, the term "striking face" refers to the front of the club head that is configured to strike a golf ball. The term striking face can be used interchangeably with the term "face."

[0033] As used herein, the term "striking face perimeter" can refer to the edge of the striking face. The striking face perimeter can be located along the outer edge of the striking face where the curvature deviates from the bulge and / or roll of the striking face.

[0034] The term "geometric center point" or "geometric center" of the striking face as described herein can refer to the geometric center point of the striking face perimeter and the midpoint of the face height of the striking face. In the same or other examples, the geometric center point can also be centered with respect to an engineered impact zone and can be defined by an area of ​​grooves on the striking face. As another approach, the geometric center point of the striking face can be located according to a definition of a golf governing body, such as the United States Golf Association (USGA).

[0035] The term "ground plane" as used herein may refer to a reference plane associated with the surface on which the golf ball rests. The ground plane may be the horizontal plane that is in contact with the sole at the address position.

[0036] As used herein, the term "loft plane" may refer to a reference plane that is tangent to the striking face at its geometric center point.

[0037] The term "loft angle" as used herein may refer to the angle measured between the loft plane and the XY plane (defined below).

[0038] As used herein, the term "face height" may refer to the distance between the top of the striking face perimeter and the bottom of the striking face perimeter measured parallel to the loft plane.

[0039] The term "lie angle" as used herein may refer to the angle between a hosel axis extending through the hosel and the ground plane. The lie angle is measured from a front view.

[0040] The "depth" of the golf club head as described herein may be defined as the dimension from the front to the rear of the golf club head.

[0041] The "height" of a golf club head as described herein may be defined as the dimension from the top rail to the sole of the golf club head. In many embodiments, the height of the club head may be measured according to a golf governing body, such as the United States Golf Association (USGA).

[0042] The "length" of a golf club head as described herein may be defined as the heel-to-toe dimension of the golf club head. In many embodiments, the length of the club head may be measured according to a golf governing body, such as the United States Golf Association (USGA).

[0043] The "face height" of the golf club head described herein may be defined as the height measured parallel to the loft plane between the upper end of the striking face perimeter near the top rail and the lower end of the striking face perimeter near the sole.

[0044] The "geometric center height" of a golf club head as described herein is the height measured perpendicularly from the ground plane to the geometric center point of the golf club head.

[0045] The "leading edge" of the club head described herein may be identified as the sole-most portion of the periphery of the striking face.

[0046] The "XYZ" coordinate system of the golf club head described herein is based on the geometric center of the striking face. The dimensions of the golf club head described herein can be measured based on the coordinate system as defined below. The geometric center of the striking face defines a coordinate system with an origin located at the geometric center of the striking face. The coordinate system defines an X-axis, a Y-axis, and a Z-axis. The X-axis passes through the geometric center of the striking face in a heel-to-toe direction of the club head. The Y-axis passes through the geometric center of the striking face in a top rail-to-sole direction of the golf club head. The Y-axis is perpendicular to the X-axis. The Z-axis passes through the geometric center of the striking face in a front-to-back direction of the golf club head. The Z-axis is perpendicular to both the X-axis and the Y-axis.

[0047] The term or phrase "center of gravity location" or "CG location" may refer to the location of the club head's center of gravity (CG) relative to an XYZ coordinate system, with the CG location characterized by location along the X, Y, and Z axes. The term "CGx" may refer to the CG location along the X-axis, measured from the origin. The term "CG height" may refer to the CG location along the Y-axis, measured from the origin. The term "CGy" may be synonymous with CG height. The term "CG depth" may refer to the CG location along the Z-axis, measured from the origin. The term "CGz" may be synonymous with CG depth.

[0048] The XYZ coordinate system of the golf club head described herein defines an XY plane extending through the X and Y axes. The coordinate system defines an XZ plane extending through the X and Z axes. The coordinate system further defines a YZ plane extending through the Y and Z axes. The XY, XZ, and YZ planes are all perpendicular to one another and intersect at a coordinate system origin located at the geometric center of the striking face. In these or other embodiments, the golf club head can be viewed from the front when the striking face is viewed perpendicular to the XY plane. Additionally, in these or other embodiments, the golf club head can be viewed from a side or cross-sectional side view when the heel is viewed perpendicular to the YZ plane.

[0049] The golf club head further comprises a coordinate system centered at the center of gravity. The coordinate system has an X'-axis, a Y'-axis, and a Z'-axis. The X'-axis extends in a heel-to-toe direction. The X'-axis is positive toward the heel and negative toward the toe. The Y'-axis extends in a sole-to-top direction and is perpendicular to both the Z'-axis and the X'-axis. The Y'-axis is positive toward the top rail and negative toward the sole. The Z-axis extends from front to rear, is parallel to the contact surface, and is perpendicular to both the X'-axis and the Y'-axis. The Z'-axis is positive toward the striking face and negative toward the rear.

[0050] The term or phrase "Moment of Inertia" (hereinafter "MOI") may refer to a value measured for the CG. The term "MOIxx" may refer to the MOI measured in a heel-to-toe direction parallel to the X' axis. The term "MOIyy" may refer to the MOI measured in a sole-to-top rail direction parallel to the Y axis. The term "MOIzz" may refer to the MOI measured in a front-to-back direction parallel to the Z axis. The MOI values ​​MOIxx, MOIyy, and MOIzz determine how forgiving a club head is for off-center impacts with a golf ball.

[0051] The term "iron" as described herein can refer, in some embodiments, to an iron-type golf club head having a loft angle that is less than about 50 degrees, less than about 49 degrees, less than about 48 degrees, less than about 47 degrees, less than about 46 degrees, less than about 45 degrees, less than about 44 degrees, less than about 43 degrees, less than about 42 degrees, less than about 41 degrees, or less than about 40 degrees. Additionally, in many embodiments, the loft angle of the club head is greater than about 16 degrees, greater than about 17 degrees, greater than about 18 degrees, greater than about 19 degrees, greater than about 20 degrees, greater than about 21 degrees, greater than about 22 degrees, greater than about 23 degrees, greater than about 24 degrees, or greater than about 25 degrees.

[0052] The term "wedge" as described herein can refer, in some embodiments, to a wedge-type golf club head having a loft of greater than about 40 degrees, greater than about 41 degrees, greater than about 42 degrees, greater than about 43 degrees, greater than about 44 degrees, greater than about 45 degrees, greater than about 46 degrees, greater than about 47 degrees, greater than about 48 degrees, greater than about 49 degrees, or greater than about 50 degrees. Additionally, in many embodiments, the loft of the wedge-type golf club head is less than about 65 degrees, less than about 64 degrees, less than about 63 degrees, less than about 62 degrees, less than about 61 degrees, or less than about 60 degrees.

[0053] In many embodiments, such as the "game improvement irons," the club head volume is approximately 65 cm 3Less than 60cm 3 Less than 55cm 3 Less than or about 50cm 3 In some embodiments, the volume of the club head is less than about 50 cm 3 ~about 60cm 3 , approx. 51cm 3 ~Approx. 53cm 3 , approx. 53cm 3 ~55cm 3 , approx. 55cm 3 ~Approx. 57cm 3 , or about 57 cm 3 ~Approx. 59cm 3 It can be said that:

[0054] In many embodiments, such as "players irons," the club head volume is approximately 45 cm 3 Less than 40cm 3 Less than 35cm 3 Less than or about 30cm 3 In some embodiments, the volume of the club head is less than about 31 cm 3 ~Approx. 38cm 3 (1.9 cubic inches to 2.3 cubic inches), approx. 31 cm 3 ~Approx. 33cm 3 , about 33cm 3 ~Approx. 35cm 3 , about 35cm 3 ~Approx. 37cm 3 , or about 37 cm 3 ~Approx. 39cm 3 It can be said that:

[0055] In some embodiments, the irons can have a total mass ranging between 180 and 300 grams, between 190 and 240 grams, between 200 and 230 grams, between 210 and 220 grams, or between 215 and 220 grams. In some embodiments, the total mass of the club head is 215 grams, 216 grams, 217 grams, 218 grams, 219 grams, or 220 grams.

[0056] Before any embodiments of the present disclosure are described in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings, as the disclosure is capable of other embodiments and of being practiced or carried out in various ways.

[0057] Described herein are methods, apparatus and articles of manufacture relating to golf clubs in general, and golf club heads in particular. The methods, apparatus and articles of manufacture described herein are not limited in this respect.

[0058] (explanation) Described herein is a method for manufacturing a forged iron-type golf club head having a cavity (multi-stage forging process). A forged iron-type golf club head manufactured via a multi-stage forging process achieves similar shape and mass properties of a similar cast club while having the beneficial material properties and ease of manufacture achieved by forging. The forged iron-type golf club head includes a rear cavity configured to receive an insert. The cavity and insert increase the discretionary mass that can be allocated to other portions of the club head, such as the perimeter and sole, increasing the moment of inertia and lowering the center of gravity, respectively.

[0059] 1 to 4 are diagrams for explaining a manufacturing method (multi-stage forging process) for a forged iron-type golf club head having a cavity. The manufacturing method for an iron-type golf club head having a cavity includes a rough forging stage, a hot pressing stage, and a precision forging stage. The manufacturing method for an iron-type golf club head having a forged cavity shown in FIG. 5 can form one iron-type golf club head having a cavity, or can form a set of iron-type golf club heads having cavities.

[0060] A single iron-type golf club head with a cavity formed by a multi-stage forging process can include loft angles ranging from 60 degrees to 16 degrees. In many embodiments, the loft angle of the club head is less than about 60 degrees, the loft angle of the club head is less than about 59 degrees, the loft angle of the club head is less than about 58 degrees, the loft angle of the club head is less than about 57 degrees, the loft angle of the club head is less than about 56 degrees, the loft angle of the club head is less than about 55 degrees, the loft angle of the club head is less than about 54 degrees, the loft angle of the club head is less than about 53 degrees, the loft angle of the club head is less than about 52 degrees, the loft angle of the club head is less than about 51 degrees, the loft angle of the club head is less than about 50 degrees, less than about 49 degrees, less than about 48 degrees, less than about 47 degrees, less than about 46 degrees, less than about 45 degrees, less than about 44 degrees, less than about 43 degrees, less than about 42 degrees, less than about 41 degrees, or less than about 40 degrees. Further, in many embodiments, the loft angle of the club head is greater than about 16 degrees, greater than about 17 degrees, greater than about 18 degrees, greater than about 19 degrees, greater than about 20 degrees, greater than about 21 degrees, greater than about 22 degrees, greater than about 23 degrees, greater than about 24 degrees, or greater than about 25 degrees.

[0061] Additionally, the multi-stage forging process can form multiple iron-type golf club heads with cavities that include different lofts (as discussed above) to form a set of golf clubs (i.e., 2 iron, 3 iron, 4 iron, 5 iron, 6 iron, 7 iron, 8 iron, 9 iron, PW). In some embodiments, the multi-stage forging process can form multiple iron-type golf club heads with the same sized cavities and different lofts to form a set of golf clubs.

[0062] (A. Rough forging) 1, the multi-stage forging process includes four stages: (1) a rough forging stage in which an intermediate club head body 10 is formed from a solid block billet (not shown), (2) a hot pressing stage in which a cavity 58 is formed in the intermediate club head body, (3) a precision forging stage in which the intermediate club head body 10 is formed into a final golf club head 80, and (4) an insert 110 or filler is placed into the cavity 58 of the golf club head body 80. This multi-stage forging process allows a manufacturer to create a forged golf club head 80 with a deep undercut cavity 58 from a single solid billet. In some embodiments, the multi-stage forging process can include a fifth stage (not shown) in which a shaft and a grip are attached to the golf club head body 80 to form a golf club.

[0063] To begin the multi-stage forging process, a billet of material is provided. The billet is forged into an iron-type golf club head and can be any one or more combinations of 8620 alloy steel, S25C steel, carbon steel, maraging steel, stainless steel, stainless steel alloy, tungsten, aluminum, aluminum alloy, or any metal suitable for forging. The billet can be a solid block with no cavities or other materials attached to it. Additionally, the billet does not monolithically encase other materials. One or more materials can be present on a surface of the billet, multiple surfaces of the billet, or corners of the billet.

[0064] In another embodiment, the solid billet can include two or more metals. The multi-metal billet is forged into an iron-type golf club head and can be any one or more combinations of 8620 alloy steel, S25C steel, carbon steel, maraging steel, stainless steel, stainless steel alloy, tungsten, aluminum, aluminum alloy, or any metal suitable for forging. The multi-metal billet does not monolithically encase other materials. The multi-metal billet can include a base metal with at least one different metal on a surface of the billet, at least one different metal on multiple surfaces of the billet, or at least one different metal on a corner of the billet.

[0065] The next step in the multi-stage forging process is forging the billet into intermediate club head 10. Referring to FIG. 2, intermediate club head body 10 is formed from a solid block billet that is rough forged by first upper die 12 and first lower die 14. First upper die 12 and first lower die 14 form the desired club head shape. The solid block billet is heated to a desired temperature between 700-1100° C. to make the billet highly malleable so that forging can occur. In some embodiments, the desired billet temperature for rough forging is 700-725°C, 725-750°C, 750-775°C, 775-800°C, 800-825°C, 825-850°C, 850-875°C, 875-900°C, 900-925°C, 925-950°C, 950-975°C, 975-1000°C, 1000-1025°C, 1025-1050°C, 1050-1075°C, or 1075-1100°C. In one embodiment, the desired billet temperature for rough forging is 800-825°C.

[0066] Once the solid block billet is heated to a desired temperature, the first upper die 12 and the first lower die 14 apply a desired pressure to the billet to shape the malleable billet into a desired geometric shape. The desired pressure applied to the billet by the first upper die 12 and the first lower die 14 is between 500 tons and 800 tons (1 ton is equivalent to 2000 pounds of force). In some embodiments, the desired pressure of the upper die 12 and the lower die 14 is 500-525 tons, 525-550 tons, 550-575 tons, 575-600 tons, 600-625 tons, 625-650 tons, 650-675 tons, 675-700 tons, 700-725 tons, 725-750 tons, 750-775 tons, and 775-800 tons. In some embodiments, the desired pressure of the upper and lower dies 12, 14 is between 600 tons and 625 tons. The high pressure of the upper and lower dies 12, 14 quickly forms the malleable solid block billet into the desired geometric shape, thus preserving the material and tensile properties of the metal billet.

[0067] 2 is a cross-sectional view of the upper and lower dies 12, 14 forming the intermediate club head body 10 from a solid block billet. The intermediate club head body 10 formed from the rough forging includes a sole 16, a top rail 18, a striking face 20, a rear wall 22 of the striking face 20, and a rear portion 24. The striking face 20 has a heel end (not shown), a toe end (not shown), an upper region 30, a lower region 32, and a striking surface 33. The striking surface 33 is parallel to the lower region 32 of the striking face 20 and is the desired plane along which the striking face 20 will be folded in a later step. The upper region 30 faces the rear wall 22 of the striking face 20, while the lower region 32 faces the rear portion 24.

[0068] Rear portion 24 extends away from striking face 20 and is adjacent to sole 16. Rear portion 24 further includes upper edge 38. Upper edge 38 is generally perpendicular to striking face 33 and lower region 32. Upper edge 38 provides a surface or shelf for forming a cavity therein in a subsequent step. Rear portion 24 further includes a non-linear perimeter 40. Upper edge 38 extends from the heel end to the toe end. Non-linear perimeter 40 connects sole 16 to upper edge 38 of rear portion 24.

[0069] The rear wall 22 of the striking face 20 is adjacent the top rail 18 and the upper edge 38 while being parallel to the upper region 30 of the striking face 20. The rear wall 22 of the striking face 20 extends generally from the heel end to the toe end.

[0070] The upper and lower regions 30, 32 of the striking face of the intermediate club head body 10 are divided by an intersecting plane 34, which is perpendicular to the lower region 32 and striking surface 33 of the striking face 20. The intersecting plane 34 is also generally parallel to the upper edge 38 of the rear portion 24. The intersecting plane 34 allows for the forging of a cavity in the rear portion 24 of the intermediate club head body 10. The intersecting plane 34 is the plane about which the striking face 20 bends and is the bending point to create the cavity 58 from the forged billet.

[0071] The intersecting plane 34 extends approximately parallel to the ground contact plane 35, which intersects with the sole 16. In most embodiments, the ground contact plane 35 is tangential and parallel to the sole 16. In some embodiments, the ground contact plane 35 is not parallel to the sole 16, but intersects with the sole 16 at an angle.

[0072] Additionally, an intersecting plane 34 intersects the striking face of the intermediate club head body 10 and generally bisects the intermediate club head body 10, dividing it into an upper region 30 and a lower region 32. The intermediate club head body 10 further includes a height measured from the sole 16 to the top rail 18. In most embodiments, the intersecting plane 34 intersects the intermediate club head body 10 between 20-70% of the height of the club head body 10. In some embodiments, the intersecting plane 34 intersects the club head body 10 at approximately 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65% or 70% of the height of the club head body 10. In some embodiments, the intersecting plane 34 intersects the club head body 10 at approximately 20%-30%, 30%-40%, 40%-50%, 50%-60%, or 60%-70% of the height of the club head body 10, or any other suitable percentage height value between these percentage height values, and can range from any one of these percentage height values ​​to any other one of these percentage height values.

[0073] A clearance angle 36 is formed between the intersecting surface 34 and the upper region 30 of the striking face 20. The clearance angle 36 allows sufficient space for the second upper die 54 and the second lower die 56 to subsequently form a cavity 58 in the intermediate club head 10. The clearance angle 36 may range from 1° to 89°. In some embodiments, the clearance angle 36 may range from 5° to 35°. In other embodiments, the clearance angle 36 may range from 5° to 11°, 9° to 18°, and 13° to 35°. In other embodiments, the clearance angle 36 can be 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34° and 35°.

[0074] In other embodiments, the multi-stage forging process may include additional intermediate steps from those shown in FIG. 1. The intermediate steps may be implemented to further aid in shaping the cavity, create texture and detail on the surface of the cavity, and create an aesthetically pleasing appearance. For example, FIG. 14 illustrates another embodiment of a multi-stage forging process that includes six steps: (1) a rough forging stage in which an intermediate club head body 10 is formed from a solid block billet (not shown); (2) a machining stage in which a cavity is roughly formed in the intermediate club head body; (3) a hot pressing stage in which the cavity 58 is expanded and formed into a more final shape; (4) a precision forging stage in which the cavity is finally formed; (5) another precision forging stage in which texture and detail are formed in the club head body; and (6) an insert 110 or filler is placed into the cavity 58 of the golf club head body 80. This multi-stage forging method allows a manufacturer to create a forged golf club head 80 with a deep undercut cavity 58 from a single solid billet. In some embodiments, the multi-stage forging process may include a seventh stage (not shown) in which the shaft and grip are attached to the golf club head body 80 to form the golf club.

[0075] The multi-stage forging process shown in Figure 14 is similar in many respects to the embodiment of Figure 1. For example, both the embodiments of Figure 14 and Figure 1 each include a first rough forging step in which an intermediate club head having a curved striking face is formed, as described above. Conversely, the multi-stage forging process of Figure 14 differs from the process illustrated in Figure 1 in that the process of Figure 14 includes an intermediate machining step after the first rough forging step described above.

[0076] (B. Machining of cavity) In some embodiments, the multi-stage forging process may include an additional step of preforming a cavity 58 in the intermediate club head body 10. In this second step, preforming the cavity 58 is accomplished through the use of a rough cutting operation. The rough cutting operation removes material along the top edge 38 of the rear portion 24 to form a preformed cavity. The rough cutting operation creates the approximate dimensions of the cavity to aid in the next step of the multi-stage forging process. The preformed cavity aids the second top die 54 in forming the final cavity 58 by removing material from the rear portion such that the second top die 54 extrudes less material from the cavity 58.

[0077] (C. Cavity Formation) Referring to FIG. 3, the next step in the multi-stage forging process is the formation of a cavity 58 in the intermediate club head body 10. The formation of the cavity 58 from the intermediate club head body 10 is accomplished by one or more of the following processes: hot pressing, machining, cutting, drilling, or mechanical punching. The embodiment of FIG. 3 illustrates a hot pressing technique. The hot pressing technique utilizes a second upper die 54 and a second lower die 56 (where the second upper die 54 and the second lower die 56 differ in shape from the first upper die 12 and the first lower die 4 of the rough forging stage) to precisely dimension the cavity 58 approximately perpendicular to the top edge 38 at the rear portion 24 of the intermediate club head body 10. The second upper die 54 has a sharp geometry that penetrates the top edge 38 of the rear portion 24, and the second lower die 56 holds the intermediate club head 10 at the desired clearance angle 36, thereby forming the cavity 58.

[0078] In the embodiment of the multi-stage forging method in which the method includes the second rough machining step described above, the second top die 54 has the exact shape of the cavity and is inserted into the preform cavity created by the previous rough machining step. The preform cavity created in the previous step aids in cavity formation by requiring less material to be displaced or shaped by the hot pressing step, allowing the die to be partially inserted into the preform cavity. In this embodiment in which the intermediate club head has a preformed cavity, the second top die 54 does not need to have a sharp shape to penetrate the rear body because the preformed cavity aids in inserting the second die into the rear without having to penetrate material.

[0079] In both of the above methods, the temperature required to hot press the cavity 58 in the intermediate club head body 10 can range from 700° C. to 1150° C. This high heat is necessary for the hot pressing process to avoid strain hardening of the metal during deformation, which would make the intermediate club head body 10 less malleable and would make the formation of the cavity 58 more difficult. In some embodiments, the temperature required to hot press the cavity 58 in the intermediate club head body 10 may be in the range of 700-725°C, 725-750°C, 750-775°C, 775-800°C, 800-825°C, 825-850°C, 850-875°C, 875-900°C, 900-925°C, 925-950°C, 950-975°C, 975-1000°C, 1000-1025°C, 1025-1050°C, 1050-1075°C, 1075-1100°C, 1100-1125°C, or 1125-1150°C. In one embodiment, the temperature required to hot press the cavity 58 in the intermediate club head body 10 may be in the range of 775°C to 800°C.

[0080] Once the intermediate club head body 10 is heated to the desired temperature, the second lower die 56 applies a desired pressure to the intermediate club head body 10 to maintain its shape (striking face 20 folded about intersecting plane 34 at the desired clearance angle 36). A cavity 58 is then formed as the second upper die 54 applies a desired pressure and a sharp geometry penetrates the upper edge 38 and into the rear portion 24. The desired pressure applied to the intermediate club head body 10 by the second upper die 54 and second lower die 56 is between 500 tons and 800 tons (one ton is equivalent to 2000 pounds of force). In some embodiments, the desired pressure of the second upper mold 54 and the second lower mold 56 is 500-525 tons, 525-550 tons, 550-575 tons, 575-600 tons, 600-625 tons, 625-650 tons, 650-675 tons, 675-700 tons, 700-725 tons, 725-750 tons, 750-775 tons, and 775-800 tons. In some embodiments, the desired pressure of the upper mold 54 and the lower mold 56 is between 675 tons and 700 tons. The high pressure of the second upper mold 54 and the second lower mold 56 quickly forms the cavity 58 in the intermediate club head body 10, thus maintaining the material and tensile properties of the metal intermediate club head body 10.

[0081] The cavity 58, formed by the methods described above including hot pressing, includes a lower surface 60 and two interior walls 62. The cavity 58 further comprises a surface area and volume that can provide a surface and area for mounting an insert in a later process.

[0082] Additionally, the cavity 58 includes a cavity axis 69. The cavity axis 69 passes through the lowest point of the lower surface 60 of the cavity 58. The cavity axis 69 exactly bisects the cavity 58 and is equidistant from the inner surface wall 68 of the cavity 58. The cavity 58 can be hot pressed at an angle 71, where the press angle 71 is measured from the cavity axis 69 to the intersection plane 34. The press angle can range from 60° to 90°. In some embodiments, the press angle 71 can range from 60° to 65°, 65° to 70°, 70° to 75°, 75° to 80°, and 85° to 90°, or any other suitable press angle 71 value between these press angles 71, and can range from any one of these press angles 71 to any other one of these press angles 71. In other embodiments, the press angle 71 can be 60°, 61°, 62°, 63°, 64°, 65°, 66°, 67°, 68°, 69°, 70°, 71°, 72°, 73°, 74°, 75°, 76°, 77°, 78°, 79°, 80°, 81°, 82°, 83°, 84°, 85°, 86°, 87°, 88°, 89°, or 90°. The press angle 71 allows the insert to be fixed (in a later step) in the cavity 58 at a desired angle. Additionally, the press angle 71 allows a set of iron-type golf club heads with cavities to be formed via a multi-stage forging process with the same press angle 71 and / or different press angles 71.

[0083] Additionally, the cavity 58 may have a substantially triangular, rectangular, square, semicircular, parabolic, or trapezoidal cross-section. In some embodiments, the cavity 58 may include a different cross-section at a toe end of the cavity 58 and a heel end of the cavity 58.

[0084] In some embodiments, the cavity 58 is about 0.8cc, 1.0cc, 1.25cc, 1.5cc, 1.75cc, 2.0cc, 2.25cc, 2.5cc, 2.75cc, 3.0cc, 3.25cc, 3.5cc, 3.75cc, 4.0cc, 4.25cc, 4.5cc, 4.75cc, 5.0cc, 5.25cc, 5.5cc, 5.75cc, 6.0cc, 6.25cc, 6.5cc, 6.75cc, 7.0cc, 7.25cc, 7.5cc, 7.75cc, 8.0cc, 8.25cc, 8.5cc, 8.75cc, 9.0cc, 9.25cc, 9.5cc, 9.75cc, 10.0cc 10.25cc, 10.5cc, 10.75cc, 11.0cc, 11.25cc, 11.5cc, 11.75cc, 12.0cc, 12.25cc, 12.5cc, 12.75cc, 13.0cc, 13.25cc, 13.5cc, 13.75cc, 14.0cc, 14.25cc, 14.5cc, 14.75cc, 15.0cc, 15.25cc, 15.5cc, 15.75cc, 16.0cc, or any other suitable volume between these volumes, and may range from any one of these volumes to any other one of these volumes. In one embodiment, the volume of the cavity 58 is 4.25cc. The volume of the cavity 58 may be substantially similar to the volume of the insert secured within the cavity 58.

[0085] In some embodiments, the cavity 58 is approximately 3.00 to 4.00 cm 2 , 4.00~5.00cm 2 , 5.00~6.00cm 2 , 6.00~7.00cm 2 , 7.00~8.00cm 2 , 8.00~9.00cm 2 , 10.00~11.00cm 2 , 11.00~12.00cm 2 , 12.00~13.00cm 2 , 13.00~14.00cm 2 , 14.00~15.00cm 2 , 15.00~16.00cm 2 , 16.00~17.00cm2 , 17.00~18.00cm2, 18.00~19.00cm2, 19.00~20.00cm 2 , 20.00~21.00cm 2 , 21.00~22.00cm 2 , 22.00~23.00cm 2 , 23.00~24.00cm 2 , 24.00~25.00cm 2 , 25.00~26.00cm 2 , 26.00~27.00cm 2 , 27.00~28.00cm 2 , 28.00~29.00cm 2 Or 29.00~30.00cm 2 In other embodiments, the surface area of ​​cavity 58 can be any other suitable surface area between those surface areas and can range from any one of those surface area values ​​to any other one of those surface areas. The surface area of ​​cavity 58 can be substantially similar to the surface area of ​​the insert secured within cavity 58.

[0086] In some embodiments, the cavity 58 is approximately 0.05 inches (1.27 mm), 0.10 inches (2.54 mm), 0.15 inches (3.81 mm), 0.20 inches (5.08 mm), 0.25 inches (6.35 mm), 0.30 inches (7.62 mm), 0.35 inches (8.89 mm), 0.40 inches (10.16 mm), 0.45 inches (11.43 mm), 0.50 inches (12.7 mm), 0.55 inches (13.97 mm), 0.60 inches (15.24 mm), 0.70 inches (16.24 mm), 0.75 inches (18.24 mm), 0.70 inches (19.24 mm), 0.75 inches (20.24 mm), 0.70 inches (21.24 mm), 0.75 inches (22.24 mm), 0.75 inches (23.24 mm), 0.75 inches (25.24 mm), 0.75 inches (26.24 mm), 0.75 inches (27.24 mm), 0.75 inches (28.24 mm), 0.75 inches (29.24 mm), 0.75 inches (30.24 mm), 0.75 inches (31.24 mm), 0.75 inches (32.24 mm), 0.75 inches (33.24 mm), 0.75 inches (34.24 mm), 0.75 inches (35.24 mm), 0.75 inches (36.24 mm), 0.75 inches (37.24 mm), 0.75 inches (38.24 mm), 0.75 inches (39.24 mm), 0.75 inches (40.24 mm), 0.75 inches (41.24 mm), 0.7 ), 0.65 inches (16.51 mm), 0.70 inches (17.78 mm), 0.75 inches (19.05 mm), 0.80 inches (20.32 mm), 0.85 inches (21.59 mm), 0.90 inches (22.86 mm), 0.95 inches (24.13 mm), 1.0 inch deep (25.4 mm), or any other suitable depth therebetween and may range from any one of these depths to any other one of these depths. The depth of the cavity 58 may be substantially similar to the height of the insert secured within the cavity 58.

[0087] Following the formation of cavity 58 in intermediate club head body 10, a final precision forging step is performed to correct the clearance angle 36 into the final golf club head.

[0088] (D. Precision forging) After hot pressing the cavity 58 into the intermediate club head body 10, the club head body 10 is precision forged. The striking face 20 is bent to a final angle 96. The final angle 96 is formed between the intersecting surface 34 and the striking face 20. The final angle 96 is between approximately 88°-92° or between 88°, 89°, 90°, 91° or 92°, thereby aligning the upper region 30 with the lower region 32 of the club head body 10. The intermediate club head body 10 is then further forged into the final golf club head 80.

[0089] 4, this precision forging stage includes a third upper die 82 and a third lower die 84, which are formed into a desired shape (wherein the second upper die 54, the second lower die 56, the first upper die 12 and the first lower die 14 are different in shape from the third upper die 82 and the third lower die 84). The third upper die 82 and the third lower die 84 apply a desired pressure to the intermediate club head body 10, bending the upper portion 30 of the striking face 20 into alignment with the lower portion 32 of the striking face 20 in the striking surface 33, thereby bending the clearance angle 36 to a final angle 96 of approximately 90° with respect to the intersecting surface 34. The intermediate club head body 10 is then forged into the final golf club head 80, with the striking face 20 continuously straight and capable of functioning for its intended purpose of striking a golf ball.

[0090] To perform this stage of the method, the intermediate club head body 10 formed in the previous step must be heated to a desired temperature to bend the striking face 20 into the striking surface 33. The intermediate club head body 10 is heated to a desired temperature of 700°C to 1100°C. In some embodiments, the desired temperature of the intermediate club head body 10 for precision forging is 700-725°C, 725-750°C, 750-775°C, 775-800°C, 800-825°C, 825-850°C, 850-875°C, 875-900°C, 900-925°C, 925-950°C, 950-975°C, 975-1000°C, 1000-1025°C, 1025-1050°C, 1050-1075°C, or 1075-1100°C. In one embodiment, the desired temperature of the intermediate club head body 10 for rough forging is between 800-825°C.

[0091] Once the intermediate club head body 10 is heated to the desired temperature, the lower die 84 maintains the shape of the cavity and lower part 32 while the third upper die 82 is pressed against the rear wall 22. The third upper die 82 presses the upper part 30 of the intermediate club head body 10 tightly against the third lower die 84, thus aligning the upper part 30 with the lower part, thereby bending the clearance angle 36 to approximately 90° with respect to the intersecting plane 34. The desired pressure applied to the intermediate club head body 10 by the third upper die 82 and the third lower die 84 is between 500 tons and 800 tons (one ton is equivalent to 2000 pounds of force). In some embodiments, the desired pressure of the third upper mold 82 and the third lower mold 84 is 500-525 tons, 525-550 tons, 550-575 tons, 575-600 tons, 600-625 tons, 625-650 tons, 650-675 tons, 675-700 tons, 700-725 tons, 725-750 tons, 750-775 tons, and 775-800 tons. In some embodiments, the desired pressure of the third upper mold 82 and the third lower mold 84 is 675 tons to 700 tons. The greater pressure of the upper mold 82 and the third lower mold 84 maintains the shape of the lower portion 32 and the cavity 58 along the lower region 32 while compressing the upper portion 30, thus resulting in a functioning striking face 20. The striking face is then removed from the third upper and lower molds 82, 84 and allowed to cool in a room temperature environment until it is safe to touch.

[0092] In some embodiments, a core piece may be placed in the cavity prior to the precision forging process. The core piece is placed in the cavity to prevent deformation during the precision forging process. Due to the extreme pressures of precision forging, in some cases the cavity shape may be compromised by the expansion of the material being forced into the cavity. The core piece acts as a placeholder to prevent unwanted deformation in the cavity during the precision forging process. The core piece helps to maintain the precise shape and tolerances of the cavity 58. In some embodiments of the multi-stage forging process, the process may further include a second precision forging method.

[0093] (E. Secondary precision forging) Following the first precision forging step described above, the multi-stage forging process may include additional precision forging steps, as shown in FIG. 14. The second precision forging step may be used to create the overall final dimensions of the club head body, while also forming any desired aesthetic designs and features in the club head body. For example, the second precision forging step may form details in the rear wall 22. The details may include small grooves, channels, fillets, chamfers, protrusions, or other small variations to the geometric shapes that combine to create a visually appealing club head.

[0094] The second precision forging process may include a core piece disposed within the cavity, similar to the first precision forging process described above. As described above, the core piece helps prevent deformation of the cavity during the second precision forging process so that the cavity maintains its precise final shape and tolerances.

[0095] After the second precision forging step, the golf club head may include excess material from the forging sequence at the periphery of the club head (i.e., where the upper and lower dies meet). A final finishing step may be used to remove the excess material from the periphery. Machining, cutting, pressing, drilling, or other methods may be used to remove this material.

[0096] (F. Insert placement) Referring to FIG. 5, following the three stages of forging the final golf club head 80, an insert 110 may be attached to the inner wall 62 and the underside 60 of the cavity 58. In some embodiments, nothing is placed in the cavity 58. The insert 110 differs from the core piece described above in that the insert is made of a lightweight material and designed to fit within the final golf club head. The core piece is a hard and rigid part designed to withstand the pressures of forging that are not present in the final golf club head. The insert 110 may be secured within the cavity 58 by adhesive, press fit, mechanical fastening, or any other suitable method of securing the insert 110. The insert 110 may be made of one or more elastomers. For example, the insert 110 may be made of a non-ferrous thermoplastic urethane, a hybrid plastic having a mixture of iron particles or other ferrous alloy particles mixed into a thermoplastic elastomeric polymer, polyurethane, or other elastomeric polymer. In other embodiments, the insert 110 can be a metal such as aluminum, steel, tungsten, in the form of beads in a polymer, a powder metal in suspension that is hardened in a polymer, or other suitable metal when the insert 110 is sintered or machined, etc.

[0097] Additionally, the insert 110 can occupy the entire cavity 58 or a percentage of the cavity 58. The percentage of the cavity 58 that is occupied can range from 5% to 100%. In some embodiments, the percentage of the cavity 58 that is occupied can range from 5% to 15%, 15% to 25%, 25% to 35%, 35% to 45%, 45% to 55%, 55% to 65%, 65% to 75%, 75% to 85%, 85% to 95%, or 95% to 100%. In one embodiment, the percentage of the cavity 58 that is occupied is in the range of 95% to 100%.

[0098] In many embodiments, the insert 110 can have a weight that can be advantageously configured to stiffen the striking face 20, beneficially minimize undesirable impact vibrations, and / or establish or adjust the swing weight of the golf club during assembly. For example, the insert 110 can have a mass between about 1.0 g and about 100 g. For example, the tuning element 150 can have a mass between about 1.0 g, 2.0 g, 3.0 g, 4.0 g, 5.0 g, 6.0 g, 7.0 g, 8.0 g, 9.0 g, 10.0 g, 11.0 g, 12.0 g, 13.0 g, 14.0 g, 15.0 g, 16.0 g, 17.0 g, 18.0 g, 19.0 g, 20.0 g, 21.0 g, 22.0 g, 23.0 g, 24.0 g, 25.0 g, 26.0 g, 27.0 g, 28.0 g, 29.0 g, 30.0 g, 31.0 g, 32.0 g, 33.0 g, 34.0 g, 35.0 g, 36.0 g, 37.0 g, 38.0 g, 39.0 g, 40.0 g, 41.0 g, 42.0 g, 43.0 g, 44.0 g, 45.0 g, 46.0 g, 47.0 g, 48.0 g, 49.0 g, 50.0 g, 51.0 g, 52.0 g, 53.0 g, 54.0 g, 55.0 g, 56.0 g, 57.0 g, 58.0 g, 59.0 g, 60.0 g The mass of the insert 110 may be 0 g, 28.0 g, 29.0 g, 30.0 g, 35.0 g, 40.0 g, 45.0 g, 50.0 g, 55.0 g, 60.0 g, 65.0 g, 70.0 g, 75.0 g, 80.0 g, 85.0 g, 90.0 g, 95.0 g, 100.0 g, or any other suitable mass between these masses, ranging from any one of these masses to any other one of these masses. For example, in some embodiments, the insert 110 may have a mass of about 1.0 g to about 30.0 g.

[0099] In some embodiments, the insert 110 can have a density of about 1.0 g / cc to about 20.0 g / cc. For example, the insert 110 can have a density of about 1.0 g / cc, 1.5 g / cc, 2.0 g / cc, 2.5 g / cc, 3.0 g / cc, 3.5 g / cc, 4.0 g / cc, 4.5 g / cc, 5.0 g / cc, 5.5 g / cc, 6.0 g / cc, 6.5 g / cc, 7.0 g / cc, 7.5 g / cc, 8.0 g / cc, 8.5 g / cc, 9.0 g / cc, 9.5 g / cc, 10.0 g / cc, 10.5 g / cc, 11.0 g / cc, 11.5 g / cc, 12.0 g / cc, 12.5 g / cc, 13.0 g / cc, 14.0 g / cc, 15.0 g / cc, 16.0 g / cc, 17.0 g / cc, 18.0 g / cc, 19.0 g / cc, 20.0 g / cc, 21.0 g / cc, 22.0 g / cc, 23.0 g / cc, 24.0 g / cc, 25.0 g / cc, 26.0 g / cc, 27.0 g / cc, 28.0 g / cc, 29.0 g / cc, 30.0 g / cc, 31.0 g / cc, 32.0 g / cc, 33.0 g / cc, 34.0 g / cc, 35.0 g / cc, 36.0 g / cc, 37.0 g / cc, 38.0 g / cc, 39.0 g / cc, 40.0 g / cc, 41.0 g / cc, 42 cc, 13.0g / cc, 13.5g / cc, 14.0g / cc, 14.5g / cc, 15.0g / cc, 15.5g / cc, 16.0g / cc, 16.5g / cc, 17.0g / cc, 17.5g / cc, 18.0g / cc, 18.5g / cc, 19.0g / cc, 19.5g / cc, 20.0g / cc, or any other suitable density range between these densities, and may range from any one of these density values ​​to any other one of these densities.

[0100] 5, the final golf club 80 formed by the above-described manufacturing process is a forged iron-type golf club head having a cavity 58. The final golf club 80 includes a hosel 120, a top rail 122, a sole 124, a toe region 126, a heel region 128, a rear portion 130, a striking face 20 (not shown), the cavity 58, and an insert 110.

[0101] (G. Manufactured golf club head) The multi-stage forging process described above produces a forged iron-type clubhead having a rear cavity and an elastomeric insert. The forged iron-type clubhead produced can have mass properties similar to a cast cavity-back clubhead with the additional mass savings from the cavity and elastomeric insert. The mass savings further allows discretionary mass to be placed lower on the periphery of the clubhead to increase the moment of inertia and lower the center of gravity. The forged iron clubhead produced can further have the shape and grain structure of a traditional forged iron. The forged iron clubhead produced can have the look and solid feel characteristic of a traditional forged iron. In this manner, the forged iron produced combines the mass property advantages of a cast cavity-back clubhead with the look and feel of a traditional forged iron. The forged iron clubhead produced can have a variety of shapes, which are described in more detail below. The various shapes can be achieved by modifying the shape of the forging die described above.

[0102] (Embodiment 1) A first exemplary embodiment of a forged iron produced by using a multi-stage forging process is shown in Figures 6-9. In this embodiment, the forged iron club head has a deep (approximately 15 mm in at least one embodiment) and narrow (approximately 2.5 mm in at least one embodiment) forging cavity 258. This forging cavity 258 is approximately 12 mm deeper and approximately 5 mm narrower than the second embodiment presented below (but is not limited to this). The deep and narrow cavity is achieved by forcing additional material into the sole 224 to form a larger cavity. This additional material displaced in the forging process creates a larger sole. The deep and narrow cavity of the illustrated embodiment can improve ball speed by locating the cavity closer to the striking face. The cavity protrudes into a larger area of ​​the striking face surface, increasing face flexure and trampoline effect. The cavity also moves material and weight from the center of the club head toward the sole, which in some embodiments, can lower the CG by approximately (but not limited to) 1.3 mm and increase the Iyy by 200 g*cm compared to conventional forged irons. 2 Increase (but is not limited to)

[0103] The forged iron club head 200 includes a top rail 222, a sole 224 opposite the top rail 222, a hosel 220, a toe region 226, a heel region 228 opposite the toe region 226, a rear portion 230, a striking face 202, a cavity 258, and an insert 210. The club head 200 further includes an upper rear region 240 and a lower rear region 250. The upper rear region 240 extends from the top rail 222 downwardly to the lower rear region 250, extending to the toe region 226 and the heel region 228 such that the upper rear region 240 terminates at a top of the lower rear region 250. The lower rear region 250 extends upward from the sole 224 to the upper rear region 240, extending into the toe region 226 and heel region 228 such that the lower rear region terminates at the bottom of the upper rear region 240. The upper rear region 240 has a perimeter weight defined by a thickened area of ​​material extending rearwardly from the striking face 202. The lower rear region 250 is a thickened area. The lower rear region 250 further includes a forging cavity 258. The forging cavity extends generally from the top rail toward the sole.

[0104] The forging cavity 258 has a front wall 262, a rear wall 252, a bottom wall 272, a toe wall (not shown), and a heel wall 256. The front wall 262 and the rear wall 252 extend from the top rail in a sole-to-sole direction and from the heel to the toe direction. The front wall 252 is located adjacent the striking face 202 and the rear wall 252 is located rearward of the front wall 262. The heel wall 256 and the toe wall connect the front wall 262 and the rear wall 252 at the heel region 228 and the toe region 226, respectively. The front wall 262, the rear wall 252, the heel wall 256, and the toe wall define the forging cavity 258.

[0105] The forging cavity 258 further has a width 270 and a depth 260. The width 270 is measured perpendicular to the striking face 202 from the front wall 262 to the rear wall 252. In most embodiments, the width 270 is tapered such that the width 270 at the top of the exposed cavity 258 is greater than the width 270 at the bottom of the cavity 258. The tapered width 270 allows for tooling to be removed during the forging process. In some embodiments, the width 270 can range from 1.2 mm to 12.7 mm at either the top or bottom of the cavity 258. For example, the width 270 at the top of the cavity 258 can range from 1.2 mm to 12.7 mm, and the width 270 at the bottom of the cavity can range from 1.2 mm to 10.2 mm. In the illustrated embodiment, in at least one embodiment, the width 270 of the cavity 258 at the top is about 3.1 mm and the width at the bottom of the cavity is about 2.29 mm. The width of the cavity is about 5 mm narrower at the top of the cavity and about 4 mm narrower at the bottom of the cavity compared to, but not limited to, exemplary embodiment 2 presented below.

[0106] The depth 260 of the cavity 258 is measured generally in a top-to-bottom direction parallel to the striking face 202 (i.e., in a direction from the top rail 222 to the sole 224). The depth 260 is measured from the top of the rear wall 252 to the bottom wall 272 of the forging cavity 258. The depth 260 of the cavity 258 can range from 1.9 mm to 20 mm. For example, the depth 260 can range from 1.9 mm to 5 mm, 5 mm to 10 mm, 10 mm to 15 mm, or 15 mm to 20 mm. In a first embodiment, the depth 260 of the cavity 258 is about 15 mm. In at least one embodiment, the cavity depth is about 12 mm deeper than (but not limited to) the exemplary embodiment 2 presented below.

[0107] The forged iron 200 further includes a top rail thickness 232. The top rail thickness 232 is the thickness of the top rail 222 measured in a direction perpendicular to the striking face 202 to the back 230. In some embodiments, the forged cavity back iron can have a top rail thickness 232 in the range of about 4.8 mm to 8.3 mm. For example, the top rail thickness 232 can be in the range of about 4.8 mm to 5 mm, 5 mm to 5.2 mm, 5.2 mm to 5.4 mm, 5.4 mm to 5.6 mm, 5.6 mm to 5.8 mm, 5.8 mm to 6 mm, 6 mm to 6.5 mm, 6.5 mm to 7 mm, 7 mm to 7.5 mm, 7.5 mm to 8 mm, or 8 mm to 8.3 mm. The forged cavity back irons can have a top rail thickness 232 of approximately 4.8 mm, 5 mm, 5.2 mm, 5.4 mm, 5.6 mm, 5.8 mm, 6 mm, 6.2 mm, 6.4 mm, 6.6 mm, 6.8 mm, 7 mm, 7.2 mm, 7.4 mm, 7.6 mm, 7.8 mm, 8 mm, or 8.3 mm. The forged cavity back iron in the illustrated embodiment has a top rail thickness 232 of approximately 6.6 mm.

[0108] The forged iron 200 further has a blade length 234. The blade length 234 is the length of the sole 224 measured from the heel-most end to the toe-most end. In some embodiments, the forged cavity back iron can have a blade length 234 in the range of 63 mm to 73 mm. For example, the blade length 234 can be in the range of 63 mm to 65 mm, 65 mm to 67 mm, 67 mm to 69 mm, 69 mm to 71 mm, or 71 mm to 73 mm. The forged cavity back iron can have a blade length 234 of 63 mm, 64 mm, 65 mm, 66 mm, 67 mm, 68 mm, 69 mm, 70 mm, 71 mm, 72 mm, or 73 mm. The forged cavity back iron of the illustrated embodiment has a blade length 234 of approximately 70 mm.

[0109] In a first embodiment shown in FIG. 6 and FIG. 7, the forged iron 200 further includes a toe screw weight 245. In other embodiments, the forged iron 200 does not include a toe screw weight 245. In embodiments including a toe screw weight 245, the toe screw weight 245 can have a mass ranging from 1 gram to 20 grams. For example, the toe screw weight 245 may have a mass of approximately 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, 7 grams, 8 grams, 9 grams, 10 grams, 11 grams, 12 grams, 13 grams, 14 grams, 15 grams, 16 grams, 17 grams, 18 grams, 19 grams, or 20 grams. Additionally, the toe portion of the club head 200 has a thickened portion that angles from the sole 224 to the top rail 222. This thickness provides more mass to the periphery of the club head 200 compared to a conventional forged iron head, improving the MOI of the golf club head.

[0110] The club head 200 further has a coordinate system similar to that defined above. The club head 200 defines a loft plane 203 tangent to a face center 205 of the striking face 202. The club head 200 defines a contact surface 204 tangent to the sole 224 when the club head 200 is in an address position. The face center 205 of the striking face 202 defines the origin of a coordinate system having an x-axis 206, a y-axis 207, and a z-axis 208. The x-axis 206 is a horizontal axis that passes through the face center 205 and extends parallel to the contact surface 204 in a direction extending from near the heel 228 to near the toe 226. The y-axis 207 is a vertical axis that passes through the face center 205 and extends perpendicular to the contact surface 204 from near the sole 224 to near the top rail 222. The y-axis 207 is perpendicular to the x-axis 206. The z-axis 208 is a horizontal axis that passes through the face center 205, is parallel to the contact surface 204, and extends from the striking face 202 to the rear 230. The z-axis 208 is perpendicular to the x-axis 206 and the y-axis 207. The x-axis 206 extends in a positive direction toward the heel 228. The y-axis 207 extends in a positive direction toward the top rail 222. The z-axis 208 extends in a positive direction toward the rear 230.

[0111] The club head further includes a center of gravity (CG) 211. In many embodiments, the CG 211 is located within the coordinate system defined above. The CG 211 can have a location on an X-axis 206, a Y-axis 207, and a Z-axis 208. The CG 211 further defines the origin of a coordinate system having an X'-axis 212, a Y'-axis 213, and a Z'-axis 214. The X'-axis 212 extends through the CG 211 from near the heel 228 to near the toe 226. The Y'-axis 213 extends through the CG 211 from near the top rail 222 to near the sole 224, the Y'-axis 213 being perpendicular to the X'-axis 212. The Z'-axis 214 extends through the CG 211 from near the striking face 202 to near the rear 230, and is perpendicular to both the X'-axis 212 and the Y'-axis 213.

[0112] The CGx-axis 212 is parallel to the x-axis 206 , the CGy-axis 213 is parallel to the y-axis 207 , and the CGz-axis 214 is parallel to the z-axis 208 .

[0113] The club head 200 further has a moment of inertia Iyy (i.e., heel-to-toe moment of inertia) about the CGy axis 213. In some embodiments, the forged cavity back iron 200 has a stiffness of 2000 g*cm 2 From 2750g*cm 2 For example, in some embodiments, Iyy can be configured to be in the range of 2000 g*cm 2 , 2050g*cm 2 , 2100g*cm 2 , 2150g*cm 2 , 2200g*cm 2 , 2250g*cm 2 , 2300g*cm 2 ,2350g*cm 2 ,2400g*cm 2 ,2450g*cm 2 ,2500g*cm 2 ,2550g*cm 2 ,2600g*cm 2 ,2650g*cm 2 ,2700g*cm 2 , or 2750g*cm2 In the illustrated embodiment, the forged cavity back iron 200 has a weight of 2323 g*cm 2 Iyy.

[0114] The forged cavity back iron 200 further has a CG position (CGy 215) measured along the Y-axis 207. In some embodiments, the forged cavity back iron 200 can have a CGy 215 in the range of -3 mm to -4.5 mm. For example, in some embodiments, the CGy can be in the range of -3 mm to -3.25 mm, -3.25 mm to -3.5 mm, -3.5 mm to -3.75 mm, -3.75 mm to -4 mm, -4 mm to -4.5 mm. In some embodiments, the CGy 215 can be -3 mm, -3.1 mm, -3.2 mm, -3.3 mm, -3.4 mm, -3.5 mm, -3.6 mm, -3.7 mm, -3.8 mm, -3.9 mm, -4.0 mm, -4.1 mm, -4.2 mm, -4.3 mm, -4.4 mm, or -4.5 mm. In an exemplary embodiment, the forged cavity back iron 200 has (but is not limited to) a CGy215 of -3.88mm, which is lower than a conventional forged iron due to the deeper cavity.

[0115] The manufactured forged cavity back iron 200 created via the multi-stage forging method disclosed herein provides the ability to create a rear cavity in the forged iron, which provides the benefits of forging, such as tighter grain structure and ease of manufacturing, while providing the benefits of a cavity back iron, such as lower CG, higher MOI, and improved sound and feel. Additionally, in the specific embodiment described above, the forged cavity back iron 200 has a deeper, narrower forged cavity 258 to improve face flexure and promote more bending of the striking face upon impact with a golf ball. In other embodiments, the forged cavity back iron can have other shapes to modify certain characteristics of the club head to achieve desired performance.

[0116] (Embodiment 2) 10-12 illustrate a second exemplary embodiment of a forged cavity back iron club head 300 manufactured according to the multi-stage forging process described herein. In this embodiment, the forged cavity back iron club head 300 has a rear forged cavity formed via a multi-stage forging process as described above. The forging of the rear cavity removes heavy club head material from the central region of the club head and replaces it with lighter material. This redistributes mass to the perimeter and sole regions of the club head, increasing the club head's moment of inertia and lowering the center of gravity.

[0117] The second embodiment of the forged cavity back iron club head 300 is similar to the first embodiment club head 200 described above in that the forged cavity back iron 300 has a forged cavity 358 at the rear of the club head. The club head 300 differs from the club head 200 in that the rear cavity 358 has a different geometry than the rear cavity 258 to achieve desired mass properties. Specifically, while not applicable to all embodiments, in an exemplary embodiment, the rear cavity 358 may be approximately 12 mm shallower and approximately 5 mm wider. The shallower, wider cavity 358 is easier to manufacture than the rear cavity 258 while still providing substantial mass savings that can be allocated to the sole area to lower the center of gravity of the club head.

[0118] The golf club head 300 includes a top rail 322, a sole 324 opposite the top rail 322, a hosel 320, a toe region 326, a heel region 328 opposite the toe region 326, a rear portion 330, a striking face 302, a cavity 358, and an insert 310. The club head 300 further includes an upper rear region 340 and a lower rear region 350. The upper rear region 340 extends through the toe region 326 and the heel region 328 and extends downwardly from the top rail 322 to the lower rear region 350 such that the upper rear region 340 terminates at the top of the lower rear region 350. The lower rear region 350 extends into the toe region 326 and heel region 328 and extends upward from the sole 324 to the upper rear region 340 such that the lower rear region terminates at the bottom of the upper rear region 340. The upper rear region 340 includes a perimeter weight formed and defined by an area of ​​increased thickness such that material extends rearward from the striking face 302. The lower rear region 350 is an area of ​​increased thickness. The lower rear region 350 further includes a forging cavity 358.

[0119] The forging cavity 358 has a width 370, a depth 360, and a length 375. The width 370 is measured generally in a front-to-rear direction (i.e., away from the striking face 302 toward the rear 330) from the front wall 362 to the rear wall 352. In most embodiments, the width 370 is tapered such that the width 370 at the top of the exposed cavity 358 is greater than the width at the bottom of the cavity 358. The tapered width 358 allows for tool removal during the forging process. In some embodiments, the width 370 may range from 1.25 mm to 19 mm. For example, in the illustrated embodiment, the width 370 at the top of the cavity 358 is approximately 8 mm, and the width 370 at the bottom of the cavity is approximately 6.42 mm.

[0120] The depth 360 of the cavity 358 is measured generally in a top-to-bottom direction parallel to the striking face 302 (i.e., from the top rail 322 toward the sole 324). The depth 360 is measured from the top of the rear wall 352 to the bottom wall 372. In some embodiments, the depth 360 may range from 2.2 mm to 38 mm. In a second embodiment, the depth 360 of the cavity 358 is approximately 3 mm.

[0121] The length 375 of the cavity 358 is measured generally in a heel-to-toe direction from the heel wall of the cavity to the toe wall of the cavity. In some embodiments, the cavity length 375 can range from about 19 mm to 70 mm. For example, in some embodiments, the cavity length 375 can range from about 19 mm to 25 mm, 25 mm to 35 mm, 35 mm to 45 mm, 45 mm to 50 mm, 50 mm to 55 mm, 55 mm to 60 mm, 60 mm to 65 mm, or 65 mm to 70 mm. In the illustrated embodiment, the length is about 43 mm.

[0122] The forged iron insert 310 has an exposed surface 395. The exposed surface 395 is the surface of the insert 310 that is visible from the outside of the golf club head. In some embodiments, the area of ​​the exposed surface 395 is 60 mm 2 From 640mm 2 In the second embodiment of Figures 10-12, the area of ​​exposed surface 395 can range from about 342 mm 2 It is.

[0123] The forged cavity back iron further has a top rail thickness 332. The top rail thickness 332 is the thickness of the top rail 322 measured in a direction perpendicular to the striking face 302 to the rear 330. In some embodiments, the forged cavity back iron can have a top rail thickness 332 in the range of about 4.8 mm to 8.3 mm. For example, the top rail thickness 332 can be in the range of about 4.8 mm to 5 mm, 5 mm to 5.2 mm, 5.2 mm to 5.4 mm, 5.4 mm to 5.6 mm, 5.6 mm to 5.8 mm, 5.8 mm to 6 mm, 6 mm to 6.5 mm, 6.5 mm to 7 mm, 7 mm to 7.5 mm, 7.5 mm to 8 mm, or 8 mm to 8.3 mm. The forged cavity back irons can have a top rail thickness 332 of approximately 4.8 mm, 5 mm, 5.2 mm, 5.4 mm, 5.6 mm, 5.8 mm, 6 mm, 6.2 mm, 6.4 mm, 6.6 mm, 6.8 mm, 7 mm, 7.2 mm, 7.4 mm, 7.6 mm, 7.8 mm, 8 mm, or 8.3 mm. The forged cavity back irons of the illustrated embodiment have a top rail thickness 332 of approximately 6.6 mm. The top rail thickness 332 affects the ability to forge a cavity in the rear of the club head. Specifically, the greater the top rail thickness 332, the less clearance there is for the forging tool to form the cavity. However, making the top rail too thin, such as, but not limited to, less than 4.8 mm, reduces the moment of inertia.

[0124] The forged cavity back iron further has a blade length 334. The blade length 334 is the length of the sole 324 measured from the heel-most end to the toe-most end. In some embodiments, the forged cavity back iron can have a blade length 334 ranging from 63 mm to 73 mm. For example, the blade length can range from 63 mm to 65 mm, 65 mm to 67 mm, 67 mm to 69 mm, 69 mm to 71 mm, or 71 mm to 73 mm. The forged cavity back iron can have a blade length 334 of 63 mm, 64 mm, 65 mm, 66 mm, 67 mm, 68 mm, 69 mm, 70 mm, 71 mm, 72 mm, or 73 mm. The forged cavity back iron of the illustrated embodiment has a blade length 334 of approximately 70 mm.

[0125] As mentioned above, the length 375 of the cavity 358 may range from 19 mm to 70 mm, and the blade length 334 may range from 63 mm to 73 mm. Thus, the cavity 358 may extend substantially the entire length of the blade length 334.

[0126] In some embodiments, club head 300 can include a toe screw weight similar to the toe screw weight of club head 200. The toe screw weight may have a mass ranging from 1 gram to 20 grams. For example, the toe screw weight may have a mass of approximately 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, 7 grams, 8 grams, 9 grams, 10 grams, 11 grams, 12 grams, 13 grams, 14 grams, 15 grams, 16 grams, 17 grams, 18 grams, 19 grams, or 20 grams.

[0127] The club head 300 further has a moment of inertia Iyy about the Y' axis (i.e., heel-to-toe moment of inertia). In some embodiments, the forged cavity back iron has a moment of inertia of 2000 g*cm 2 From 2750g*cm 2For example, in some embodiments, Iyy can be in the range of 2000 g*cm 2 , 2050g*cm 2 , 2100g*cm 2 , 2150g*cm 2 , 2200g*cm 2 , 2250g*cm 2 , 2300g*cm 2 ,2350g*cm 2 ,2400g*cm 2 ,2450g*cm 2 ,2500g*cm 2 ,2550g*cm 2 ,2600g*cm 2 ,2650g*cm 2 ,2700g*cm 2 , or 2750g*cm 2 In the illustrated embodiment, the forged cavity back iron 300 has a weight of 2323 g*cm 2 Iyy.

[0128] The forged cavity back iron further has a CG position (CGy) measured along the Y-axis. In some embodiments, the forged cavity back iron 300 can have a CGy in the range of -3mm to -4.5mm. For example, in some embodiments, the CGy can be in the range of -3mm to -3.25mm, -3.25mm to -3.5mm, -3.5mm to -3.75mm, -3.75mm to -4mm, -4mm to -4.5mm. In some embodiments, the CGy can be -3mm, -3.1mm, -3.2mm, -3.3mm, -3.4mm, -3.5mm, -3.6mm, -3.7mm, -3.8mm, -3.9mm, -4.0mm, -4.1mm, -4.2mm, -4.3mm, -4.4mm, or -4.5mm. In the illustrated embodiment, the forged cavity back iron 300 has a CGy of -4.0 mm. By forming the cavity 358 and replacing the material of the golf club head 300 with the insert 310 of a lighter material, a higher mass is concentrated in the sole of the club and a lower CGy value is achieved. The CGy of the illustrated embodiment is 0.12 mm lower (but not limited to) than the CGy of embodiment 1. This lower CGy value is achieved because the cavity of the illustrated embodiment 2 is approximately 12 mm shallower (but not limited to) and approximately 5 mm wider (but not limited to) compared to embodiment 1.

[0129] The rear cavity 358 is primarily rectangular in shape. Additionally, the length 375 of the rear cavity 358 extends across a majority of the striking face 302. The insert 310 borders the rear cavity 358 on all sides except for the exposed surface 395. The edges of the walls of the rear cavity 358 are radiused to allow the cavity 358 to flex and facilitate ease of manufacturing.

[0130] Forged cavity back irons produced via the multi-stage forging method disclosed herein provide the ability to create a rear cavity in the forged iron, which provides forging advantages such as tighter grain structure and ease of manufacture, while providing cavity back iron advantages such as lower CG, higher MOI, etc. The shape of the cavity in the forged cavity back iron of embodiment 2 has the added advantage of being easier to forge than that of embodiment 1. The difference in the shape of the cavity in the embodiment facilitates the forging process, but the rest of the manufacturing process remains largely unchanged.

[0131] Third embodiment 15-17 show a third exemplary embodiment of a final forged cavity back iron 400 produced according to the multi-stage forging process described herein. In this embodiment, the final forged cavity back iron 400 has a rear forged cavity formed via a multi-stage forging process as described above. The forged rear cavity removes mass from the center of the club head and redistributes mass to the perimeter and sole regions to increase the moment of inertia and lower the center of gravity, respectively.

[0132] The forged iron 400 in the illustrated embodiment is similar to the previous embodiments described above in that the forged iron has a cavity formed through the use of a multi-stage forging process. The forged iron illustrated in Figures 15-17 differs from the embodiment illustrated in Figures 6-12 in that the forged iron has a different cavity shape and face shape. Specifically, the striking face has different thicknesses in different areas. Additionally, the cavity and the rear of the forged iron have different angles and shapes compared to the previous embodiments. These shapes, which are described in more detail below, improve ease of manufacture while also improving performance.

[0133] The forged iron 400 includes a hitting face 402. The hitting face 402 has three regions, a top region 480, a middle region 484, and a cavity region 488, as shown in FIG. 15. The top region 480 has a first height 481 and a first thickness 482. The middle region 484 has a second height 485 and a second thickness 486. The cavity region 488 has a third height 489 and a variable thickness. The first thickness 482, the second thickness 486, and the variable thickness are measured perpendicular to the loft plane in a front-to-back direction. The height of each region is measured parallel to the loft plane in a top-to-bottom direction. FIGS. 15-17 show cross-sectional views of the club head along the YZ plane, as defined above. The YZ plane is a plane that intersects the geometric center of the striking face and extends from the top rail toward the sole and from the front to the rear. The shapes described below are measured in the YZ plane (mid-plane).

[0134] As shown in FIG. 16, the first thickness 482 of the apex region is approximately 2.46 mm. In other embodiments, the first thickness 482 may be in the range of approximately 1.9 mm to 2.8 mm. For example, the first thickness 482 may be in the range of approximately 1.9 mm to 2.0 mm, 2.0 mm to 2.1 mm, 2.1 mm to 2.2 mm, 2.2 mm to 2.3 mm, 2.3 mm to 2.4 mm, 2.4 mm to 2.5 mm, 2.5 mm to 2.6 mm, 2.6 mm to 2.7 mm, or 2.7 mm to 2.8 mm. The first thickness 482 is greater than the second thickness 486. In the illustrated embodiment, the first thickness 482 is approximately constant throughout the apex region 480. The apex region 480 may be defined by the first thickness 482.

[0135] The first height 481 of the top region 480 can be in the range of about 3 mm to 12 mm. For example, the first height 481 can be in the range of about 3 mm to 5 mm, 5 mm to 7 mm, 7 mm to 9 mm, 9 mm to 11 mm, or 11 mm to 12 mm. In the illustrated embodiment, the first height 481 is about 7.6 mm.

[0136] The top region 480 may further include an appearance feature, which may be a groove or other pattern imprinted on the top region. In embodiments having an appearance feature, the first thickness 482 is measured as the maximum thickness.

[0137] As shown in FIG. 16, the second thickness 486 of the intermediate region 484 is approximately 1.9 mm. In other embodiments, the second thickness 486 can range from approximately 1.3 mm to 2.3 mm. For example, the second thickness 486 can range from approximately 1.3 mm to 1.5 mm, 1.5 mm to 1.7 mm, 1.7 mm to 1.9 mm, 1.9 mm to 2.1 mm, or 2.1 mm to 2.3 mm. The second thickness 486 is less than the first thickness 482 and is variable in thickness. The second thickness 486 is approximately constant throughout the intermediate region 484.

[0138] The intermediate region 484 is the region where the striking face 402 bends during the rough forging process, as described above. Thus, the second thickness 486 of the intermediate region affects the bending characteristics of the forging process. Specifically, as the second thickness 486 decreases, more bending is permitted such that the clearance angle 36 decreases. However, making the second thickness 486 too thin compromises the durability of the striking face. Additionally, the second thickness 486 affects the spacing of the cavity 458 relative to the striking face 402. Reducing the second thickness 486 allows the cavity 458 to be formed closer to the striking face 402.

[0139] The second height 485 of the intermediate region 486 affects bending characteristics in a similar manner to the thickness 486. As the second height 485 decreases, the ability to bend the striking face 402 during forging becomes more difficult. Additionally, as the second height 484 decreases, the clearance angle 36 must be decreased (i.e., bent more) to provide adequate clearance for the forging press to form the cavity 458.

[0140] As shown in FIG. 15, the second height 485 of the intermediate region 484 is approximately 5.1 mm. In other embodiments, the second height 485 may be in the range of approximately 0.6 mm to 7.6 mm. For example, the second height 485 may be in the range of 0.6 mm to 1 mm, 1 mm to 2 mm, 2 mm to 3 mm, 3 mm to 4 mm, 4 mm to 5 mm, 5 mm to 6 mm, 6 mm to 7 mm, 7 mm to 7.6 mm. The second height 485, as well as the second thickness, affect the bending characteristics of the striking face during the rough forging process. Additionally, the intermediate region 484 is located above the face center 405 such that the intermediate region 484 does not include the face center 405. The intermediate region 484 is located above the cavity region 488 and below the top region 480. By locating the intermediate region 484 above the face center 405, the intermediate region 484 can be made thinner since approximately 80% of players impact the golf ball at or below the face center 405. Thus, the intermediate region 484 does not receive a significant number of impacts.

[0141] The second thickness 486 further aids in removing the core piece after the final forging step. As mentioned above, the core piece is used to prevent deformation of the cavity during the final forging step where the striking face is bent back to form the final club head. The second height 485 should be large enough so that the core piece has enough room to be pulled up and out of the cavity. If the second height 485 is not large enough, the core piece may get stuck or scratch the iron when it is being removed.

[0142] As discussed above, the cavity region 488 is located below the intermediate region 484. The cavity region 488 has a rear cavity 458. The cavity region 488 has a minimum thickness 490 and a maximum thickness 491. The minimum thickness 490 defines a top boundary of the cavity region 488 and the maximum thickness 491 defines a bottom boundary of the cavity region 488. The thickness of the cavity region 488 increases from top to bottom due to the draft angle of the cavity 458. The cavity region 488 further has a face center 405 such that the cavity 458 and the insert 410 can be located directly behind or near the face center 405. Locating the insert 410 behind and near the face center improves the sound and feel of the club head.

[0143] The minimum thickness 490 of the cavity region 488 is approximately 2.76 mm in the illustrated embodiment. In other embodiments, the minimum thickness 490 of the cavity region 488 may range from approximately 2.2 mm to 3.8 mm. For example, the minimum thickness 490 may range from approximately 2.2 mm to 2.6 mm, 2.6 mm to 3 mm, or 3 mm to 3.8 mm. Reducing the minimum thickness 490 allows the cavity to be closer to the striking face and impact location, which in turn allows the elastomeric insert to be closer to the striking face and face center, improving sound and performance. By moving the insert closer to the face center, the vibration of the club head at impact is better dampened, improving sound and spacing. Multi-stage forging allows for a smaller minimum thickness 490 due to the larger clearance of the upper die when the cavity is hot pressed into the rear of the club head. Forged irons made by conventional methods cannot produce cavities with minimum thicknesses equivalent to those of the claimed invention. Conventionally forged irons require the rear cavity to be machined, but the top rail and other features of the striking face do not allow the machine enough clearance to machine the cavity close to the striking face, so conventionally forged irons have cavities further away from the striking face than the present invention.

[0144] The maximum thickness 491 of the cavity region 488 is approximately 3.73 mm in the illustrated embodiment. In other embodiments, the maximum thickness 491 of the cavity region 488 may range from approximately 2.5 mm to 5 mm. For example, the maximum thickness 491 may range from 2.5 mm to 3 mm, 3 mm to 3.5 mm, 3.5 mm to 4.0 mm, 4.0 mm to 4.5 mm, or 4.5 mm to 5 mm. The maximum thickness 491 is measured from the front wall 462 adjacent the bottom of the cavity to the striking face 402. Like the minimum thickness 490, the maximum thickness 491 also improves sound and performance because the cavity 458 is brought closer to the striking face 402, and therefore the elastomeric insert 410 is brought closer to the striking face 402.

[0145] The forged iron 400 further includes an offset distance. The offset distance is the difference between the first thickness 482 in the top region 480 and the minimum thickness 490 in the cavity region 488. The offset distance may range from about 0.1 mm to 0.6 mm. For example, the offset distance may range from about 0.1 mm to 0.2 mm, 0.2 mm to 0.3 mm, 0.3 mm to 0.4 mm, 0.4 mm to 0.5 mm, or 0.5 mm to 0.6 mm. The offset distance in the illustrated embodiment is about 0.27 mm. It is an aspect of the present invention to reduce the offset distance so that the insert can be placed closer to the striking face.

[0146] The forged iron 400 further includes a cavity top angle 468, as shown in FIG. 17. The cavity top angle 468 is the angle between a cavity top surface 465 and the striking face 402. The cavity top surface 465 extends in a heel-to-toe direction. The cavity top surface 465 further intersects a top front point 466 and a top rear point 467. The top front point 466 is the topmost point of the front wall 462. Similarly, the top rear point 467 is the topmost point of the rear wall 452. In the illustrated embodiment, the cavity top angle 468 is approximately 117 degrees. In other embodiments, the cavity top angle 468 may range from approximately 91 degrees to 130 degrees. For example, the cavity top surface angle 468 can range from about 91 degrees to 101 degrees, 101 degrees to 110 degrees, 110 degrees to 120 degrees, or 120 degrees to 130 degrees. The larger the cavity top surface angle 468, the less the striking face will have to bend during the face bending process. For example, the cavity top surface angle 468 in the illustrated embodiment is about 117 degrees, and the striking face bend angle 36 during the rough forging process was about 10-15 degrees. In other words, a larger cavity top surface angle creates more clearance for tooling.

[0147] The forged iron further has a cavity height 476. The cavity height 476 is measured from the sole surface 474 of the club to the bottom wall, parallel to the loft plane. The sole surface is perpendicular to the loft plane 403 and tangent to the sole 424. The cavity height 476 in the illustrated embodiment is approximately 11.68 mm. In other embodiments, the cavity height may range from approximately 2.5 mm to approximately 14 mm. For example, the cavity height may range from 2.5 mm to 4 mm, 4 mm to 6 mm, 6 mm to 8 mm, 8 mm to 10 mm, 10 mm to 12 mm, or 12 mm to 14 mm.

[0148] The above-described shapes of the forged iron 400 improve performance and manufacturability over the above-described embodiments 200 and 300 that lack certain shapes. The above-described shapes, in combination, allow the cavity to be located closer to the striking face, improving performance, while improving manufacturability by increasing the clearance of the tooling used to form the cavity. The shape of the cavity further improves the ability to remove the tooling from the cavity after it has been forged. The above shapes can be further adjusted to fine-tune the center of gravity location, manufacturability, and overall aesthetics of the iron.

[0149] The embodiment described above and illustrated in Figures 15-17 has a particular shape achieved by the use of the multi-stage forging process described herein, which enhances manufacturing and performance as described above. The first thickness, second thickness, and height of the intermediate portion are selected to form a cavity closer to the striking face and provide more clearance for the tool forming the cavity so that the striking face does not bend as much during the rough forging process. The reduced clearance angle improves production in a batch of forged irons. Bending the striking face more during the rough forging stage increases the chances that the material will break and reach its elastic yield limit. A batch of forged irons of the embodiment of Figures 15-17 may have a production yield of approximately 90% (1 in 10 damaged / broken), while other embodiments may have a production yield of 80% or less due to material breaking during the rough forging process.

[0150] (Fourth embodiment) 18-20 show a fourth exemplary embodiment of a final forged cavity back iron produced according to the multi-stage forging process described herein. Club head 500 is similar to club heads 200, 300, and 400 previously described in that club head 500 is forged and may have a rear cavity. Club head 500 differs from the previous embodiments in that it has a variety of geometries to vary the overall mass properties of the club head. For example, club head 500 balances face height, hosel length, blade length, sole width, and top rail thickness to provide improved mass properties.

[0151] The iron-type golf club head 500 includes a striking face 502, a back face 542 opposite the striking face 502, a top rail 522, a sole 524 opposite the top rail 522, a toe portion 526, and a heel portion 528 opposite the toe portion 526. The top rail 522, the sole 524, the toe portion 526, and the heel portion 528 each extend rearwardly from the perimeter of the striking face 502. The club head 500 further includes a ledge 554 extending upwardly from the sole 524 at least partially between the sole 524 and the top rail 522. The club head 500 further includes a hosel 520 located proximate the heel portion 528 and configured to receive a golf club shaft (not shown). The striking face 502 further defines a plurality of scorelines 518 extending in a heel-to-toe direction parallel to the ground contact surface 504.

[0152] The iron-type golf club 500 may include a rear toe portion 527 to aid in maintaining an acceptable moment of inertia. The rear toe portion 527 has an accumulation of material toward the toe end of the club. The toe portion 526 may further include a toe cavity 544 on the toe portion 526 of the club 500. The toe cavity 544 may be designed to receive a toe screw (not shown) similar to the toe screw 245 described above. In some embodiments, the toe cavity 544 may be machined into the club head. In other embodiments, the toe cavity 544 may be created during the forging process described above. The toe screw may be made from a material that is denser than the material from which the club head 500 is made. The combination of the toe screw and the rear toe portion 527 increases the Iyy of the iron-type golf club and maintains an acceptable moment of inertia. Iron-type golf club 500 may further include a rear cavity 540 to aid in adding perimeter weighting to maintain an acceptable moment of inertia.

[0153] The iron-type golf club 500 can have a rear cavity 540 formed between the rear ledge 554, the top rail 522, the toe 526, and the heel 528. The cavity 540 is formed generally parallel to the loft plane. The rear cavity 540 further includes a rear cavity face 542. The rear cavity face 542 is generally parallel to the loft plane. The rear cavity 540 removes mass from the upper center portion of the club 500. Removing mass from the upper center portion of the club pushes mass to both the perimeter and the sole 524. Pushing the mass toward the perimeter maintains an acceptable MOI. Pushing the mass toward the sole 524 lowers the CG of the iron-type golf club 500.

[0154] The iron-type golf club head 500 further includes a hosel length 536 , a blade length 534 , a face height 538 , a sole width 525 , a top rail thickness 532 , a mass, a mass moment of inertia, and a center of gravity 511 .

[0155] The hosel length 536 of the iron-type golf club 500 is measured along the hosel axis 523. The hosel axis 523 extends through the center of the hosel bore. The hosel length is measured from the top of the hosel 520 to the point where the hosel axis 523 intersects the leading edge surface 509. The leading edge surface 509 is parallel to the ground plane 504 and intersects the leading edge. The hosel length 536 can be between 44 mm and 69 mm. In some embodiments, the hosel length 536 can be 50 mm, 51 mm, 52 mm, 53 mm, 54 mm, 55 mm, 56 mm, 57 mm, 58 mm, 59 mm, 60 mm, 61 mm, or 62 mm. In some embodiments, the hosel length 536 can be between 50 mm and 55 mm, between 55 mm and 60 mm, between 60 mm and 65 mm, or between 65 mm and 68 mm. In an exemplary embodiment, the hosel length 536 is 58 mm. The hosel length 536 helps keep the center of gravity 511 of the iron-type golf club low by moving more of the club's mass toward the sole 524.

[0156] The blade length 534 of the iron-type golf club 500 is measured from the toe-most portion of the club head to the hosel transition axis 521. The hosel transition axis 521 extends perpendicular to the ground contact surface 504 in a top-to-bottom direction. The hosel transition axis 521 is located where the striking face 502 transitions to the hosel 520. The blade length 534 can be between 60 mm and 76 mm. For example, the blade length 534 can be between 60 mm and 65 mm, between 65 mm and 70 mm, or between 70 mm and 76 mm. In the illustrated embodiment, the blade length 534 is approximately 70 mm.

[0157] The face height 538 is measured from the top of the top rail 522 to the bottom of the sole 524 when the club head is in the address position. The face height 538 of the iron-type golf club 500 can be between 43 mm and 58 mm. For example, the face height 538 can be between 43 mm and 45 mm, between 45 mm and 48 mm, between 48 mm and 51 mm, between 51 mm and 54 mm, or between 54 mm and 58 mm. In an exemplary embodiment, the face height 538 is 49.5 mm. The face height 538 helps keep the center of gravity 511 low in the iron-type golf club by moving more mass toward the sole 524.

[0158] Sole width 525 is the distance measured along the Z axis between leading edge 516 and the junction of the rear wall of club head 500 with sole 525. Sole width 525 of iron-type golf club 500 can be between 12 mm and 20 mm. For example, sole width 525 can be between 12 mm and 14 mm, between 14 mm and 16 mm, between 16 mm and 18 mm, or between 18 mm and 20 mm. In an exemplary embodiment, the sole width can be 17 mm.

[0159] Top rail thickness 532 is the distance from the striking face 502 to the rearmost portion of the top rail 522, measured perpendicular to the striking face 502. The top rail thickness 532 of the iron-type golf club 500 can be between 2.5 mm and 10 mm. For example, the top rail thickness can be between 2.5 mm and 4 mm, between 4 mm and 5 mm, between 5 mm and 6 mm, between 6 mm and 7 mm, between 7 mm and 8 mm, between 8 mm and 9 mm, or between 9 mm and 10 mm. In an exemplary embodiment, the top rail thickness is approximately 6.9 mm.

[0160] The mass of the iron-type golf club head 500 can be between 220 grams and 290 grams. In some embodiments, the mass can be between 220 grams and 235 grams, between 235 grams and 245 grams, between 245 grams and 255 grams, between 255 grams and 265 grams, between 265 grams and 275 grams, or between 275 grams and 290 grams.

[0161] The above dimensions and features, such as hosel length 534, blade length 534, face height 538, sole width 525, top rail thickness 532, and rear toe 527, can be used in combination with the multi-stage forging described above to create a forged golf club head having a cavity configured to receive an insert. A forged golf club head having an insert and the above-described combination of dimensions has a substantially lower center of gravity and a higher moment of inertia, improving carry distance, launch, spin, and accuracy compared to a conventional forged iron lacking an insert. Additionally, the above-described dimensions and features can also be implemented in the above-described embodiments 200, 300, and 400 to improve mass properties and performance.

[0162] H. A set of golf clubs having similarly sized cavities and a method for manufacturing a set of forged clubs 1, the multi-stage forging process includes four stages: (1) a rough forging stage in which an intermediate club head body 10 is formed from a solid block billet (not shown), (2) a hot pressing stage in which a cavity 58 is formed in the intermediate club head body, (3) a precision forging stage in which the intermediate club head body 10 is formed into a final golf club head 80, and (4) an insert 110 or filler is placed into the cavity 58 of the golf club head body 80. This multi-stage forging process allows a manufacturer to create a forged golf club head 80 having a deep undercut cavity 58 from a single solid billet. However, in this embodiment, the multi-stage forging process includes a fifth stage (not shown) in which a shaft and a grip are attached to the golf club head body 80 to form a golf club. The multi-step forging process is then repeated to form a plurality of cavity-type golf club heads, the plurality of cavity-type golf club heads including different lofts (as described above) to form a set of golf clubs (i.e., 2 iron, 3 iron, 4 iron, 5 iron, 6 iron, 7 iron, 8 iron, 9 iron, PW).

[0163] In some embodiments, the multi-stage forging process can form multiple iron-type golf club heads with the same size cavity and different lofts to form a set of golf clubs. With the same size cavity, the inserts attached to each golf club head can all have the exact same volume, but have different densities and therefore different masses. This variability allows the inserts for each golf club head of a golf club set to have different swing weights and / or different CG positions. Furthermore, this makes the manufacture of inserts more efficient, since for each club head, only the material of the insert (and therefore the density) needs to be changed to change the weight of the insert. The inserts are manufactured with different weights to account for manufacturing tolerances (i.e., if a golf club head is assumed to weigh 425 grams, but only weighs 415 grams, a weight of 10 grams can be added to the golf club head cavity).

[0164] The above manufacturing method can produce a set of forged iron-type golf clubs having similarly sized cavities. Referring to Figure 5, the final golf club head 80 formed by the manufacturing method includes a hosel 120, a top rail 122, a sole 124, a toe region 126, a heel region 128, a rear portion 130, a striking face 20 (not shown), a cavity 58, an insert 110, a shaft (not shown), and a grip (not shown). A set of forged iron-type golf clubs can include two golf clubs, three golf clubs, four golf clubs, five golf clubs, six golf clubs, seven golf clubs, eight golf clubs, nine golf clubs, or ten golf clubs.

[0165] Each golf club in the forged iron type golf club set is approximately 0.8cc, 1.25cc, 1.5cc, 1.75cc, 2.0cc, 2.25cc, 2.5cc, 2.75cc, 3.0cc, 3.25cc, 3.5cc, 3.75cc, 4.0cc, 4.25cc, 4.5cc, 4.75cc, 5.0cc, 5.25cc, 5.5cc, 5.75cc, 6.0cc, 6.25cc, 6.5cc, 6.75cc, 7.0cc, 7.25cc, 7.5cc, 7.75cc, 8.0cc, 8.25cc, 8.5cc, 8.75cc, 9.0cc, 9.25cc, 9.5cc, 9.75cc, 10.0cc, 10.2 The cavity 58 may include a cavity having a volume of 5cc, 10.5cc, 10.75cc, 11.0cc, 11.25cc, 11.5cc, 11.75cc, 12.0cc, 12.25cc, 12.5cc, 12.75cc, 13.0cc, 13.25cc, 13.5cc, 13.75cc, 14.0cc, 14.25cc, 14.5cc, 14.75cc, 15.0cc, 15.25cc, 15.5cc, 15.75cc, 16.0cc, or may range to any other suitable volume between these volumes, and may range from any one of these volumes to any other one of these volumes. In one embodiment, the volume of the cavity 58 is 4.25cc. The volume of the cavity 58 may be substantially similar to the volume of the insert secured within the cavity 58. The volume may be approximately the same for each golf club in the forged iron type golf club set.

[0166] The above manufacturing method can produce a mixed set of forged iron-type golf club heads, where some of the set of clubs are manufactured through the multi-stage forging process disclosed herein, and the remaining part of the set is manufactured using standard forging methods. The mixed set of forged iron-type golf club heads includes at least one club in the set of clubs that has a cavity created through the forging process disclosed herein. The mixed set of forged iron-type golf club heads further includes at least one club in the set of clubs that does not have a cavity (i.e., muscle back iron) and is made through a conventional forging process. For example, in the mixed forged iron set, irons with lofts of 27 degrees or less (i.e., 5 iron, 4 iron, 3 iron, 2 iron) can have a forged cavity manufactured through the forging process described above, while irons with lofts higher than 27 degrees (i.e., 6 iron, 7 iron, 8 iron, 9 iron, PW) do not have a forged cavity. The lower lofted irons (i.e. 5-iron, 4-iron, 3-iron) are typically more difficult to hit and therefore benefit from the rear cavity created by the manufacturing method mentioned above. The rear cavity lowers the CG and improves the MOI, allowing the lower lofted irons to launch higher, making them more forgiving and overall easier to hit.

[0167] (I. Advantages) The manufacturing process disclosed is an improvement over current industry standards. A multi-stage forging process utilizes a process that allows an intermediate club head 10 to be formed with a bent striking face 20 at a clearance angle 36 and a cavity 58 to be hot pressed into the opposite side of the striking face 20. The striking face 20 is then folded back onto the functional striking face 20 to form the final golf club head 80. This bent striking face 20 technique allows manufacturers to create a forged golf club head body 80 with a deep undercut cavity 58 from a single solid billet.

[0168] By creating a fully forged golf club head 80 with a deep undercut cavity 58, a tighter grain structure of the golf club head is achieved. The tighter grain structure improves the durability of the golf club head 80. Forging the golf club head 80 with a deep undercut cavity 58 from a billet process allows for a more durable cavity style iron than current cast cavity irons due to a tighter and more consistent grain structure.

[0169] The forged cavity back irons 200, 300, 400, 500 described above further comprise a grain structure as shown in FIG. 13. The grain structure is quantified using the ASTM-E112 standard test method. The grain number is a relationship to the number of grains that can be seen through 100x magnification. In all of the above described embodiments, the forged club head has a grain number of about 7. In other embodiments, the grain number can be 6, 7, or 8. A higher ASTM-E112 grain number suggests a smaller grain size when viewed under magnification. For example, as shown in FIG. 13, a cast club head can have a grain number of about 4. As can be observed, the grain size of the cast golf club head is much larger than the grain size of the forged golf club head.

[0170] The multi-stage forging process is also more repeatable than current casting methods. Current casting methods require manual machining processes to remove excess material and clean the shape of the club head, whereas the forging process requires little or no machining. Thus, the forging process is more repeatable since there is less uncertainty from manual machining techniques. This improves the overall tolerance of the finished club head over a cast club head. Furthermore, since fewer machining processes are involved in the manufacture of the golf club head, the present invention reduces the overall cost of manufacturing a premium golf club head with an undercut cavity.

[0171] Golf club heads made from this multi-stage forging process are comparable in feel and performance to cast golf club heads of similar geometry. Because forged iron contains stronger compositions, the striking face can be made thinner, thereby increasing the flexibility of the striking face. Thus, forged irons increase ball speed and playability (shot bend) over similarly shaped cast golf club heads while maintaining or improving spin rates, acoustic properties, and feel characteristics.

[0172] Example 1 Provided below are examples comparing exemplary golf club heads according to embodiments of the present invention with control club heads. The comparative examples are intended to illustrate the advantages of forged irons made using the multi-stage forging process described above compared to forged irons currently used on the market.

[0173] The exemplary club head is a forged iron including a cavity and an insert, similar to embodiment 400 described above. The exemplary club head was manufactured through a multi-stage forging process. The first forging step of the club head was created by rough forging a solid billet of 8620 carbon steel. The club head had a curved striking face, which allowed for a hot pressing step to form a cavity at the rear. The curved striking face was then precision forged to create a manufactured golf club head having a flat striking face and a cavity configured to receive an insert. The insert was then bonded into the cavity. The cavity had a width and depth similar to the cavity of club head 300 described above. The cavity had a width of about 8 mm at the top of the cavity and a width of about 6.42 mm at the bottom of the cavity. The cavity had a depth of about 4 mm. The exemplary club is a 4 iron with a loft of about 22 degrees.

[0174] The control club heads used in the comparative examples were forged irons made using only a single forging process. The control club heads did not have a cavity. However, the control club heads had similar overall dimensions to the exemplary club heads described above.

[0175] The mass properties of the exemplary club heads were compared to the control club heads. The mass properties were measured using computer-aided design (CAD) software. Using the coordinate system defined above, the mass properties of the exemplary clubs and the control clubs were measured. CGy and Iyy were measured for each club head. CGy is the location of the center of gravity along the y-axis. In other words, CGy indicates the location of the center of gravity relative to the contact surface. Iyy is the heel-to-toe moment of inertia about the Y´-axis of the club head. [Table 1]

[0176] As shown in Table 1, the exemplary club head has a CGy of -3.88 mm and the control club head has a CGy of -2.56 mm. A higher CGy value indicates that the center of gravity is further away from the center of the face and closer to the ground (i.e., lower CG). Thus, the exemplary club head has a CGy that is 1.32 mm lower than the control club head. The lower CGy of the exemplary club head was achieved through the use of a rear cavity and insert. The rear cavity removes mass from the center of the club head, placing more mass in the lower part of the club. A lower CGy allows for a higher launch angle and increased ball speed, which is especially beneficial with longer irons such as the 4-iron.

[0177] Further, the exemplary club head has a weight of 2323 g*cm 2 and the control club head had an Iyy of 2103 g*cm 2 The exemplary club head has an Iyy of 220 g*cm 2The higher Iyy makes the club head more forgiving on mis-hits, leading to greater overall accuracy than the control club head. The forged cavity in the exemplary club head allows for more mass to be placed on the periphery of the club head, thereby increasing the moment of inertia Iyy.

[0178] The exemplary club head has been shown to increase carry distance and provide more forgiveness than the control club head by having a lower CGy location and a higher MOI value, respectively. The multi-stage forging process allows for shape refinements to achieve this lower CGy and higher Iyy. Specifically, the cavity created in the second stage of the forging process allows for more mass to be placed on the periphery of the club head, lowering the center of gravity. The depth and total volume of the cavity affect the location of the CGy. The greater the depth and the larger the volume, the more discretionary mass can be placed elsewhere in the club. Because the cavity removes mass from the central portion of the club, mass can be placed toward the sole and periphery, thereby lowering the CGy and increasing the MOI, respectively.

[0179] Example 2 Provided below are comparative examples comparing exemplary golf club heads according to embodiments of the present invention with control club heads that are intended to illustrate the equivalent mass properties of forged irons according to embodiments of the present invention as compared to control club heads produced by a casting process.

[0180] The exemplary club head is a forged iron including a cavity and an insert, similar to embodiment 400 described above. The exemplary club head was manufactured through a multi-stage forging process. The first forging step of the club head was created by rough forging a solid billet of 8620 carbon steel. The club head had a curved striking face which allowed for a cavity to be formed at the rear through a hot pressing process. The curved striking face was then precision forged to create a manufactured golf club head having a flat striking face and a cavity configured to receive an insert. The cavity had a width and depth similar to the cavity of club head 300 described above. The cavity had a width of about 8 mm at the top of the cavity and a width of about 6.42 mm at the bottom of the cavity. The cavity had a depth of about 4 mm. The exemplary club is a 4 iron with a loft of about 22 degrees.

[0181] The control club head used in this comparative example is a cast iron-type club head with a rear cavity and an insert. The control club head has similar overall dimensions as the exemplary club head described above.

[0182] The mass properties of the exemplary club heads were compared to the control club heads. The mass properties were measured using computer-aided design (CAD) software. Using the coordinate system defined above, the mass properties of the exemplary clubs and the control clubs were measured. CGy and Iyy were measured for each club head. CGy is the location of the center of gravity along the y-axis. In other words, CGy indicates the location of the center of gravity relative to the contact surface. Iyy is the heel-to-toe moment of inertia about the Y´-axis of the club head. [Table 2]

[0183] As shown in Table 1, the exemplary club head has a CGy of -3.88 mm and the control club head has a CGy of -3.81 mm. A higher CGy value indicates that the center of gravity is further from the face center and closer to the ground plane (i.e., a lower CG). Thus, the exemplary club head has approximately the same CGy as the control club head. Thus, it is possible to achieve a CGy location equivalent to that of a cast club head using only the multi-stage forging process described above. The low CGy of the exemplary club head was achieved through the use of a rear cavity and insert. The rear cavity removed mass from the center of the club head, allowing more mass to be located lower in the club.

[0184] Further, the exemplary club head has a weight of 2323 g*cm 2 and the control club head had an Iyy of 2309 g*cm 2 The exemplary club head has an Iyy of approximately 1.0 mm. Thus, the exemplary club head has approximately the same Iyy as the control club head. In this manner, it is possible to achieve an Iyy value comparable to that of a cast club head using only the multi-stage forging process described above (i.e., no cutting). The forging cavity of the exemplary club head allows for more mass to be placed on the periphery of the club head, thereby increasing the moment of inertia Iyy.

[0185] The exemplary club heads are shown to achieve mass properties nearly equivalent to the control club heads. The multi-stage forging process allows for the creation of shapes that were previously only obtainable through other manufacturing means, such as expensive and time-consuming casting and cutting. Specifically, the cavity created in the second stage of the forging process allows for more mass to be placed on the periphery of the club head, lowering the center of gravity. The depth and total volume of the cavity affect the location of the CGy. The greater the depth and the larger the volume, the more discretionary mass can be placed elsewhere in the club. Because the cavity removes mass from the central portion of the club, mass can be placed toward the sole and periphery, thereby lowering the CGy and increasing the MOI, respectively.

[0186] Example 3 Provided below are examples comparing exemplary golf club heads according to embodiments of the present invention to control club heads. The comparative examples are intended to illustrate the differences in grain structure between forged and cast irons.

[0187] The exemplary club head is a multi-stage forged iron with a cavity and an insert, similar to the club heads used in Examples 1 and 2. The exemplary club head was manufactured through a multi-stage forging process. In the first forging step, an intermediate club head was produced by rough forging a solid billet of 8620 carbon steel. The intermediate club head had a curved striking face, which allowed a hot pressing step to form a cavity at the rear. The curved striking face was then precision forged to produce a final manufactured golf club head with a flat striking face and a cavity configured to receive the insert. The insert was then bonded into the cavity. The exemplary club is a 4 iron with a loft of about 22 degrees. It should also be noted that the exemplary club head was produced with little or no cutting.

[0188] The control club head used in this comparative example is a cast iron-type club head having a rear cavity and an insert. The control club head has similar overall dimensions as the exemplary club head described above.

[0189] As shown in FIG. 13, the exemplary club head has a grain size number of 8 according to the ASTM-E112 standard test method for determining average grain size, which examines the grain at 100x magnification. Conversely, the cast control club head has a grain size number of 4. The grain size number is inversely related to the grain size. As the grain size number increases, the actual grain size appears smaller when viewed under a microscope. Similarly, as the grain size number decreases, the actual grain size appears larger when viewed under a microscope. This suggests that the grain of the exemplary embodiment is smaller and tighter than that of the control club head. As discussed above, a smaller and tighter grain structure leads to improved durability of the club head.

[0190] Example 4 Provided below are examples comparing exemplary golf club heads according to embodiments of the present invention with control club heads. The comparative examples are intended to illustrate the performance of forged irons according to embodiments of the present invention when compared to control club heads produced by conventional forging methods.

[0191] The exemplary club head is a multi-stage forged iron having a cavity and an insert, similar to the club heads used in Examples 1, 2, and 3. The exemplary club head was manufactured through a multi-stage forging process. In a first forging step, the club head was created by rough forging a solid billet of 8620 carbon steel. The club head had a curved striking face, which allowed for a cavity to be formed at the rear through a hot pressing process. The curved striking face was then precision forged to create a manufactured golf club head having a flat striking face and a cavity configured to receive an insert. The insert was then bonded into the cavity. The cavity had a width and depth similar to the cavity of the club head 300 described above. The cavity had a width of about 8 mm at the top of the cavity and a width of about 6.42 mm at the bottom of the cavity. The cavity had a depth of about 4 mm. Additionally, the striking face had a top region, a middle region, and a cavity region as described above in embodiment 400. The middle region had a thickness of about 1.9 mm. The width of the cavity region (i.e., the cavity offset distance) ranged from a minimum thickness of 2.76 mm to a maximum thickness of 3.73 mm. The exemplary club is a 4 iron with a loft of about 22 degrees.

[0192] The control club head used in this comparative example is a conventional forged blade style iron type club head. The control club head has a slightly higher CG than the exemplary club head.

[0193] Player testing was conducted to directly compare the performance of the exemplary and control club heads, and shot data was collected for all participants using a launch monitor. [Table 3]

[0194] As shown in Table 3, the exemplary club head provided participants with faster ball speeds and longer carry distances compared to the control club head. Participants experienced, on average, an increase in ball speed of approximately 1.8 mph and an average increase in additional carry distance of approximately 3.8 yards by using the exemplary club head. Additionally, the stat area statistically represents the spatial variance seen in a series of shots. The smaller the stat area, the more accurate the results. Table 3 shows that both the exemplary and control clubs had similar stat areas, with the exemplary club performing slightly better. The stat area of ​​the exemplary club was 1199 square yards and the stat area of ​​the control club was 1318 square yards.

[0195] These results showed that the exemplary club head increased ball speed and distance while decreasing the dispersion area compared to the control club head. Increased distance and accuracy are desired by golfers at all levels. In conclusion, the exemplary club head outperformed the control club head due to the improved MOI and CG values ​​achieved by using the multi-stage forging process described herein. The multi-stage forging process created a rear cavity in the exemplary club head. The rear cavity allowed for additional mass savings so that more mass could be placed lower and on the periphery of the club to lower the CG and increase the MOI, respectively. A lower CG helps increase ball speed since it is closer to and more aligned with the line of force of the club head and ball. The increased MOI helps reduce the stud area by reducing the tendency of the club head to twist upon impact with the golf ball.

[0196] Example 5 Provided below are comparative examples comparing exemplary golf club heads according to embodiments of the present invention with control club heads that are intended to illustrate the performance of forged irons according to embodiments of the present invention as compared to control club heads produced by conventional forging methods.

[0197] The exemplary club head is a multi-stage forged iron having a cavity and an insert, similar to the club heads used in Examples 1, 2, 3, and 4. The exemplary club head was manufactured through a multi-stage forging process. In a first forging step, a solid billet of 8620 carbon steel was roughly forged to create an intermediate club head. The intermediate club head had a curved striking face that could be subjected to a hot pressing process to form a cavity at the rear. The curved striking face was then precision forged to create a final golf club head having a flat striking face and a cavity configured to receive the insert. The insert was then bonded into the cavity. The cavity had a width and depth similar to the cavity of the club head used in Example 4 and embodiment 300 described above. The cavity had a width of about 8 mm at the top of the cavity and a width of about 6.42 mm at the bottom of the cavity. The cavity had a depth of about 4 mm. Additionally, the striking face had a top region, a middle region, and a cavity region as described above in embodiment 400. The middle region had a thickness of about 1.9 mm. The width of the cavity region (i.e., the cavity offset distance) ranged from a minimum thickness of 2.76 mm to a maximum thickness of 3.73 mm. The exemplary club is a 4 iron with a loft of about 22 degrees.

[0198] The control club head used in this comparative example is a conventional forged blade style iron type club head. The control club head used in this example is different from the control club head used in Example 4. The control head in this example has smaller dimensions than the control club head in Example 4.

[0199] Player testing was conducted to directly compare the performance of the exemplary club heads and the control club heads. Shot data was collected using a launch monitor for all participants. It should also be noted that the exemplary club heads used in this example were the same as the exemplary club heads used in Example 4. However, this testing was conducted at a different time of year and under different weather conditions. The players used in this testing performed differently than the players used in the testing of Example 4. Thus, the results of the exemplary club heads in each test will reflect such differences in the testing environment. [Table 4]

[0200] As shown in Table 4, the exemplary club head provided participants with faster ball speeds and longer carry distances when compared to the control club head. On average, participants experienced an increase in ball speed of approximately 2.4 mph and an increase in additional carry distance of approximately 5.8 yards by using the exemplary club head. Additionally, the stat area statistically represents the spatial variance seen in a series of shots. The smaller the stat area, the more accurate the results. Table 4 shows that both the exemplary and control clubs had similar stat areas, with the exemplary club performing better. The stat area of ​​the exemplary club was 651 square yards and the stat area of ​​the control club was 1068 square yards.

[0201] These results showed that the exemplary club head increased ball speed and distance while decreasing the dispersion area compared to the control club head. Increased distance and accuracy are desired by golfers at all levels. In conclusion, the exemplary club head outperformed the control club head due to the improved MOI and CG values ​​achieved by using the multi-stage forging process described herein. The multi-stage forging process created a rear cavity in the exemplary club head. The rear cavity allowed for additional mass savings such that more mass could be placed under and at the perimeter of the club to lower the CG and increase the MOI, respectively. A lower CG helps increase ball speed since it is closer and more aligned with the line of force of the club head and ball. The increased MOI helps reduce the stud area by reducing the tendency of the club head to twist upon impact with the golf ball.

[0202] The replacement of one or more claimed elements constitutes a reconfiguration, not a repair. Additionally, benefits, other advantages, and solutions to problems have been described in connection with particular embodiments. However, the benefits, advantages, solutions to problems, and any one or more elements that may cause any benefit, advantage, or solution to occur or become more pronounced should not be construed as a critical, necessary, or essential feature or element of any or all of the claims.

[0203] Because the Rules of Golf may change from time to time (e.g., new rules may be adopted, or old rules may be eliminated or amended, by golf standards organizations and / or governing bodies such as the United States Golf Association (USGA), the Royal and American Golf Association (R&A), etc.), golf equipment related to the apparatus, methods, and articles of manufacture described herein may or may not comply with the Rules of Golf at any particular time. Accordingly, golf equipment related to the apparatus, methods, and articles of manufacture described herein may be advertised, offered for sale, and / or sold as compliant or non-compliant golf equipment. The apparatus, methods, and articles of manufacture described herein are not limited in this respect.

[0204] Although the above examples may be described with respect to iron golf clubs, the apparatus, methods, and articles of manufacture described herein may be applicable to other types of golf clubs, such as wedge-type golf clubs, or other types of sports equipment, such as hockey sticks, tennis racquets, fishing poles, ski poles, and the like.

[0205] Moreover, embodiments and limitations disclosed in this specification are not available to the public under the doctrine of dedication if the embodiment and / or limitation (1) is not explicitly claimed in the claims and (2) is an equivalent or potential equivalent of an element and / or limitation in the claims under the doctrine of equivalents.

[0206] Various features and advantages of the disclosure are set forth in the following claims.

[0207] Clause 1: A method of manufacturing a golf club head, the method comprising the steps of providing at least one billet of material and forming the billet into an intermediate club head body by forging, wherein the intermediate body includes a sole, a top rail, a striking face, a striking face rear wall and a rear portion, wherein the rear portion of the body has an upper edge and a non-linear perimeter, wherein the striking face has an upper region and a lower region, wherein the upper region and the lower region of the striking face are divided by an intersecting plane, wherein the intersecting plane is perpendicular to the striking face lower region, wherein the striking face has an upper region and a ... the striking face is formed at a clearance angle, where the clearance angle is measured from the upper region of the striking face to the intersection plane, where the clearance angle of the striking face is between 5° and 35°; forming a cavity in the rear portion of the body by hot pressing; and bending the striking face to a final angle by forging, thereby rendering the striking face a substantially planar surface positioned for impacting a golf ball and forming a golf club head having a cavity, the final angle being 90°.

[0208] Clause 2: A method of manufacturing a golf club head as described in clause 1, wherein the golf club head comprises a sole, a top rail, a striking face, a rear wall of the striking face, a toe end, a heel end and a rear portion, the rear portion of the body having an upper edge and a non-linear periphery, the striking face having a heel end, a toe end, an upper region and a lower region, the upper region and the lower region of the striking face being divided by an intersecting plane, the intersecting plane being perpendicular to the lower region of the striking face.

[0209] Clause 3: The method of manufacturing a golf club head according to clause 1, wherein the intersecting plane is perpendicular to the lower region of the striking face and to a striking surface.

[0210] Clause 4: The method of manufacturing a golf club head according to clause 1, wherein the intersecting plane intersects the golf club head at approximately 40-50% of a height of the club head, the height of the club head being measured from the sole of the golf club head to the top rail of the golf club head.

[0211] Clause 5: The method for manufacturing a golf club head according to clause 1, wherein the cavity formed by the hot pressing step has a volume in the range of 0.2 cubic inches to 0.4 cubic inches.

[0212] Clause 6: The method of manufacturing a golf club head according to clause 1, further comprising the step of fixing an insert within the cavity.

[0213] Clause 7: The method of manufacturing a golf club head according to clause 6, wherein the insert may be secured within the cavity by adhesive, press fit, mechanical fastening or any other suitable method of securing the insert.

[0214] Clause 8: The method for manufacturing a golf club head according to clause 7, wherein a percentage of the cavity occupied by the insert is in the range of 95% to 100%.

[0215] Clause 9: The method for manufacturing a golf club head according to clause 1, wherein the golf club head has a loft angle of 19° to 60°.

[0216] Clause 10: The method of manufacturing a golf club head according to clause 1, wherein the billet does not monolithically encase another material.

[0217] Clause 11: The method for manufacturing a golf club head according to clause 2, wherein the cavity of the golf club head extends in a direction from the heel end to the toe end.

[0218] Clause 12: A method for manufacturing a golf club head as described in clause 2, wherein the cavity formed by the hot pressing step further has a cavity axis, the cavity axis passing through a lowest point of the cavity, the cavity axis exactly bisects the cavity and is equidistant from an inner wall of the cavity.

[0219] Clause 13: A method for manufacturing a golf club head according to clause 12, wherein the cavity formed by the hot pressing step further has a press angle, the press angle being measured from the cavity axis to the intersection plane.

[0220] Clause 14: The method for manufacturing a golf club head according to clause 12, wherein the press angle is in the range of 60° to 90°.

[0221] Clause 15: The method of manufacturing a golf club head according to clause 1, wherein the cavity formed by the hot pressing step further has a substantially triangular, rectangular, square, semicircular, parabolic or trapezoidal cross section.

[0222] Clause 16: The method of manufacturing a golf club head according to clause 6, wherein the insert secured within the cavity has a mass in the range between 1.0 g and about 30.0 g.

[0223] Clause 17: The method of manufacturing a golf club head according to clause 16, wherein the insert secured within the cavity has a density in the range between 1.0 g / cc and about 20.0 g / cc.

[0224] Clause 18: The method of manufacturing a golf club head according to clause 10, wherein the billet comprises one or more of 8620 alloy steel, S25C steel, carbon steel, maraging steel, stainless steel, stainless steel alloy, tungsten, aluminum, aluminum alloy or any metal suitable for forging.

[0225] Clause 19: The method of manufacturing a golf club head according to clause 10, wherein the billet comprises two or more of 8620 alloy steel, S25C steel, carbon steel, maraging steel, stainless steel, stainless steel alloy, tungsten, aluminum, aluminum alloy or any metal suitable for forging.

[0226] Clause 20: The method of manufacturing a golf club head according to clause 10, wherein the billet comprises two or more metals, at least one of the metals is 8620 alloy steel, and at least one of the metals is tungsten.

[0227] Clause 21: A forged golf club head comprising: a top rail, a sole opposite the top rail, a hosel, a toe region, a heel region opposite the toe region, a rear portion, a striking face, a lower rear region, and an upper rear region, the upper rear region being located above the lower rear region such that the upper rear region has the top rail and the lower rear region has the sole, the forged golf club head further comprising a forging cavity formed in the lower rear region, the forging cavity having a front wall adjacent the striking face, a rear wall spaced rearward of the front wall, a bottom wall, a toe wall, and a heel wall, the forging cavity having a cavity volume between 3.5cc and 6.5cc, the striking face comprising a top region, a cavity region, and a top region. and the cavity region, the top region having a first thickness measured perpendicular to the striking face and a first height measured parallel to the striking face from the top rail to the sole, the intermediate region having a second thickness measured perpendicular to the striking face and a second height measured parallel to the striking face from the top rail to the sole, the cavity region having a minimum and a maximum thickness measured perpendicular to the striking face and a third height measured parallel to the striking face from the top rail to the sole, the first thickness being greater than the second thickness and less than the minimum thickness, the second height being in a range of approximately 4 mm to 7 mm, and the forged golf club head being forged from a single solid billet.

[0228] Clause 22: The forged golf club head of clause 21, wherein the striking face defines a geometric center, the geometric center defines an origin of a coordinate system including an x-axis extending parallel to the ground surface and having a positive direction toward the heel end when the club head is in the address position, a y-axis extending perpendicular to the ground surface and having a positive direction toward the top rail when the club head is in the address position, and a z-axis extending parallel to the ground surface and having a positive direction toward the front end when the club head is in the address position, a center of gravity of the golf club head located within the coordinate system including a CGx location along the x-axis, a CGy location along the y-axis, and a CGz location along the z-axis, the CGy location ranging from -3mm to -4mm.

[0229] Clause 23: The forged golf club head of clause 22, wherein the center of gravity includes a y′ axis extending perpendicular to the ground surface and having a positive direction toward the top rail when the club head is in the address position, and a moment of inertia Iyy about the y′ axis is 2250 g*cm 2 From 2500g*cm 2 The range is.

[0230] Clause 24: The forged golf club head of clause 23, wherein the club head has a mass in the range of 220 grams to 290 grams.

[0231] Clause 25: The forged golf club head of clause 21, wherein the cavity has a depth, measured parallel to the loft plane from the bottom wall to the top of the rear wall, in the range of 2.5 mm to 5 mm.

[0232] Clause 26: The forged golf club head of clause 25, wherein the cavity has a width, measured from the front wall to the rear wall perpendicular to the loft plane, in the range of 3.8 mm to 11 mm.

[0233] Clause 27: The forged golf club head of clause 26, wherein the cavity has a top plane that intersects with an apex of the front wall and intersects with an apex of the rear wall, the cavity having a top angle that is an angle between the top plane and the loft plane, the top angle being in the range of 110 degrees to 130 degrees.

[0234] Clause 28: The forged golf club head of clause 21, wherein the second thickness ranges from about 1.5 mm to 2.5 mm.

[0235] Clause 29: The forged golf club head of clause 28, wherein the minimum thickness is in the range of 2 mm to 4 mm, and the maximum thickness is in the range of 3.2 mm to 4.5 mm.

[0236] Clause 30: The forged golf club head of clause 29, wherein the golf club head further comprises a top rail thickness, measured perpendicular to the loft plane from the striking face to a top rail rear wall, the top rail thickness ranging from approximately 6.10 mm to 6.65 mm.

[0237] Clause 31: A forged golf club head comprising: a top rail, a sole opposite the top rail, a hosel, a toe region, a heel region opposite the toe region, a rear portion, a striking face, a lower rear region, and an upper rear region, the upper rear region being located above the lower rear region such that the upper rear region has the top rail and the lower rear region has the sole, the forged golf club head further comprising a forging cavity formed in the lower rear region, the forging cavity having a front wall adjacent the striking face, a rear wall spaced rearward of the front wall, a bottom wall, a toe wall, and a heel wall, the front wall, the rear wall, the bottom wall, the toe wall, and the heel wall defining a cavity volume between 3.5 cc and 6.5 cc, the striking face comprising: a top region, a cavity region, and the forged golf club head has an intermediate region located between the top region and the cavity region, the top region having a first thickness measured perpendicular to the striking face and a first height measured parallel to the striking face from the top rail to the sole, the intermediate region having a second thickness measured perpendicular to the striking face and a second height measured parallel to the striking face from the top rail to the sole, the cavity region having a third thickness measured perpendicular to the striking face and a third height measured parallel to the striking face from the top rail to the sole, the first thickness being greater than the second thickness and less than the third thickness, the second height being in a range of approximately 0.05 inches to 0.125 inches, and the forged golf club head is forged from a single solid billet.

[0238] Clause 32: The forged golf club head of clause 31, wherein the striking face defines a geometric center, the geometric center defines an origin of a coordinate system including an x-axis extending parallel to the ground surface and having a positive direction toward the heel end when the club head is in the address position, a y-axis extending perpendicular to the ground surface and having a positive direction toward the top rail when the club head is in the address position, and a z-axis extending parallel to the ground surface and having a positive direction toward the front end when the club head is in the address position, a center of gravity of the golf club head located within the coordinate system including a CGx location along the x-axis, a CGy location along the y-axis, and a CGz location along the z-axis, the CGy location being in the range of -3mm to -4mm.

[0239] Clause 33: The forged golf club head of clause 32, wherein the center of gravity includes a y′ axis extending perpendicular to the ground surface and has a positive direction toward the top rail when the club head is in the address position, and a moment of inertia Iyy about the y′ axis is greater than or equal to 2250 g*cm 2 From 2500g*cm 2 The range is.

[0240] Clause 34: The forged golf club head of clause 33, wherein the club head has a mass in the range of 220 grams to 290 grams.

[0241] Clause 35: The forged golf club head of clause 31, wherein the cavity has a depth, measured parallel to the loft plane from the bottom wall to the top of the rear wall, in the range of 2.5 mm to 5 mm.

[0242] Clause 36: The forged golf club head of clause 35, wherein the cavity has a width, measured from the front wall to the rear wall perpendicular to the loft plane, in the range of 3.8 mm to 11 mm.

[0243] Clause 37: The forged golf club head of clause 36, wherein the cavity has a top plane that intersects with an apex of the front wall and intersects with an apex of the rear wall, the cavity having a top angle that is an angle between the top plane and the loft surface, the top angle being in the range of 110 degrees to 130 degrees.

[0244] Clause 38: The forged golf club head of clause 31, wherein the second thickness ranges from about 1.5 mm to 2.5 mm.

[0245] Clause 39: The forged golf club head of clause 38, wherein the minimum thickness is in the range of 2 mm to 4 mm, and the maximum thickness is in the range of 3.2 mm to 4.5 mm.

[0246] Clause 40: The forged golf club head of Clause 39, wherein the golf club head further comprises a top rail thickness, measured perpendicular to the loft plane from the striking face to a top rail rear wall, the top rail thickness ranging from approximately 6.10 mm to 6.65 mm.

Claims

1. 1. A forged golf club head, comprising: a top rail, a sole opposite the top rail, a hosel, a toe region, a heel region opposite the toe region, a rear portion, a striking face, a lower rear region, and an upper rear region; the upper rear region is located above the lower rear region such that the upper rear region has the top rail and the lower rear region has the sole; the forged golf club head further comprises a forging cavity formed in the lower rear region; the forging cavity has a front wall adjacent the striking face, a rear wall spaced rearward of the front wall, a bottom wall, a toe wall, and a heel wall; the front wall, the rear wall, the bottom wall, the toe wall, and the heel wall define a cavity volume between 3.5 cc and 6.5 cc; the striking face having a top region, a cavity region, and an intermediate region located between the top region and the cavity region; the top region has a first thickness measured perpendicular to the striking face and a first height measured parallel to the striking face from the top rail to the sole; the intermediate region has a second thickness measured perpendicular to the striking face and a second height measured parallel to the striking face from the top rail to the sole; the cavity area has a minimum thickness and a maximum thickness measured perpendicular to the striking face, and a third height measured parallel to the striking face from the top rail to the sole; the first thickness being greater than the second thickness and less than the minimum thickness; the second height is in the range of about 4 mm to 7 mm; The forged golf club head is forged from a single solid billet. Forged golf club head.

2. the striking face defines a geometric center, the geometric center defines an origin of a coordinate system, the coordinate system including an x-axis extending parallel to the ground surface and having a positive direction toward the heel end when the club head is in the address position, a y-axis extending perpendicular to the ground surface and having a positive direction toward the top rail when the club head is in the address position, and a z-axis extending parallel to the ground surface and having a positive direction toward the front end when the club head is in the address position; a center of gravity of the golf club head located within the coordinate system and including a CGx location along the x-axis, a CGy location along the y-axis, and a CGz location along the z-axis; The CGy position is in the range of -3 mm to -4 mm.

2. The forged golf club head of claim 1.

3. the center of gravity includes a y' axis extending perpendicular to the ground plane and having a positive direction toward the top rail when the club head is in the address position; The moment of inertia Iyy about the y' axis is 2250 g*cm ２ to 2500 g*cm ２ In the range of 3. The forged golf club head of claim 2.

4. The forged golf club head of claim 3 , wherein the club head has a mass in the range of 220 grams to 290 grams.

5. 2. The forged golf club head of claim 1, wherein the cavity has a depth, measured parallel to the loft plane from the bottom wall to the top of the rear wall, in the range of 2.5 mm to 5 mm.

6. The cavity has a width, measured perpendicular to the loft plane from the front wall to the rear wall, in the range of 3.8 mm to 11 mm.

6. The forged golf club head of claim 5.

7. the cavity has a top plane that intersects with an apex of the front wall and intersects with an apex of the rear wall; the cavity has a top angle that is an angle between the top plane and the loft surface; The top surface angle ranges from 110 degrees to 130 degrees.

7. The forged golf club head of claim 6.

8. The forged golf club head of claim 1 , wherein the second thickness ranges from about 1.5 mm to 2.5 mm.

9. the minimum thickness is in the range of 2 mm to 4 mm; The maximum thickness is in the range of 3.2 mm to 4.5 mm.

9. The forged golf club head of claim 8.

10. the golf club head further comprises a top rail thickness measured perpendicularly from the loft plane from the striking face to a top rail rear wall; The thickness of the top rail ranges from about 6.10 mm to 6.65 mm.

10. The forged golf club head of claim 9.

11. 1. A forged golf club head, comprising: a top rail, a sole opposite the top rail, a hosel, a toe region, a heel region opposite the toe region, a rear portion, a striking face, a lower rear region, and an upper rear region; the upper rear region is located above the lower rear region such that the upper rear region has the top rail and the lower rear region has the sole; the forged golf club head further comprises a forging cavity formed in the lower rear region; the forging cavity has a front wall adjacent the striking face, a rear wall spaced rearward of the front wall, a bottom wall, a toe wall, and a heel wall; the front wall, the rear wall, the bottom wall, the toe wall, and the heel wall define a cavity volume between 3.5 cc and 6.5 cc; the striking face having a top region, a cavity region, and an intermediate region located between the top region and the cavity region; the top region has a first thickness measured perpendicular to the striking face and a first height measured parallel to the striking face from the top rail to the sole; the intermediate region has a second thickness measured perpendicular to the striking face and a second height measured parallel to the striking face from the top rail to the sole; the cavity region has a third thickness measured perpendicular to the striking face and a third height measured parallel to the striking face from the top rail to the sole; the first thickness being greater than the second thickness and less than the third thickness; the second height ranges from about 0.05 inches to 0.125 inches; The forged golf club head is forged from a single solid billet. Forged golf club head.

12. the striking face defines a geometric center, the geometric center defines an origin of a coordinate system, the coordinate system including an x-axis extending parallel to the ground surface and having a positive direction toward the heel end when the club head is in the address position, a y-axis extending perpendicular to the ground surface and having a positive direction toward the top rail when the club head is in the address position, and a z-axis extending parallel to the ground surface and having a positive direction toward the front end when the club head is in the address position; a center of gravity of the golf club head located within the coordinate system and including a CGx location along the x-axis, a CGy location along the y-axis, and a CGz location along the z-axis; The CGy position is in the range of -3 mm to -4 mm.

12. The forged golf club head of claim 11.

13. the center of gravity includes a y' axis extending perpendicular to the ground plane and having a positive direction toward the top rail when the club head is in the address position; The moment of inertia Iyy about the y' axis is 2250 g*cm ２ to 2500 g*cm ２ In the range of 13. The forged golf club head of claim 12.

14. The forged golf club head of claim 13 , wherein the club head has a mass in the range of 220 grams to 290 grams.

15. 12. The forged golf club head of claim 11, wherein the cavity has a depth, measured parallel to the loft plane from the bottom wall to the top of the rear wall, in the range of 2.5 mm to 5 mm.

16. The cavity has a width, measured perpendicular to the loft plane from the front wall to the rear wall, in the range of 3.8 mm to 11 mm.

16. The forged golf club head of claim 15.

17. the cavity having an upper planar surface that intersects an apex of the front wall and intersects an apex of the rear wall; the cavity has a top angle that is an angle between the top plane and the loft surface; The top surface angle ranges from 110 degrees to 130 degrees.

17. The forged golf club head of claim 16.

18. The forged golf club head of claim 11 , wherein the second thickness ranges from approximately 1.5 mm to 2.5 mm.

19. the minimum thickness is in the range of 2 mm to 4 mm; The maximum thickness is in the range of 3.2 mm to 4.5 mm.

20. The forged golf club head of claim 18.

20. the golf club head further comprises a top rail thickness measured perpendicularly from the loft plane from the striking face to a top rail rear wall; The top rail thickness ranges from about 6.10 mm to 6.65 mm.

20. The forged golf club head of claim 19.

Images