Patent Description:
In general, iron type golf club heads can be made by a variety of methods such as casting, co-casting, metal injection molding, machine milling, and forging. Many iron type golf club heads contain cavities or filling features to adjust the performance features of the golf club head when it strikes a golf ball. Often times, irons that contain cavities are casted or co-casted, in order to achieve these advanced geometries. Milling techniques are used to create club heads with cavities from a single block of material, however this is an expensive and timely process. Further, forging techniques are often used to create an iron golf club head that is formed of an integral block of material. Forging is cheaper and quicker than milling, however the geometries that can be achieved are limited. With current industry techniques, it is difficult to quickly and cheaply create a forged iron type club head with any kind of cavity. There is a need in the art for a forged golf club head with a cavity. <CIT> discloses an iron golf club head with a face portion and a neck portion integrally molded by forging.

To facilitate further description of the embodiments, the following drawings are provided in which:.

For simplicity and clarity of illustration, the drawing figures illustrate the general manner of construction, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the present disclosure. Additionally, elements in the drawing figures are not necessarily drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of embodiments of the present disclosure. The same reference numerals in different figures denote the same elements.

Described herein is method of manufacturing an iron type golf club with a cavity, via a multi-stage forging process. The method comprises: rough forging solid block billet of a suitable metal to create an intermediate club head body, hot pressing the intermediate club head to create a cavity in the body, precision forging the intermediate club head to create a golf club body, and then attaching an insert within the cavity. The intermediate club head, formed through rough forging, comprises a bent strike face, allowing a cavity to be formed in the rear body via hot pressing. The bent strike face of the intermediate club head is then precision forged. This bent strike face technique allows a manufacturer to create a forged golf club head body with a deep undercut cavity, from a single solid billet, as the bent strike face provides room to hot press a cavity.

It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "include," and "have," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, device, or apparatus that comprises a list of elements is not necessarily limited to those elements but may include other elements not expressly listed or inherent to such process, method, system, article, device, or apparatus.

It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein. Furthermore, the term "rough forging" describes a forging technique wherein a block shaped billet is quickly formed into a general desired shape, with minimal tooling or machining.

Before any embodiments of the disclosure are explained 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.

In general, methods, apparatuses, and articles of manufacture associated with golf clubs, and in particular golf club heads are described herein. The methods, apparatuses, and articles of manufacture described herein are not limited in this regard.

<FIG> illustrate a method of manufacturing (multi-stage forging process) a forged iron-type golf club head with a cavity. The method of manufacturing the iron-type golf club head with cavity comprises a rough forging stage, a hot-pressing stage, and a precision forging stage. The method of manufacturing a forged iron-type golf club head with cavity, illustrated in <FIG>, can form a single iron-type golf club head with cavity, or a set of iron-type golf club heads with cavities.

A single iron-type golf club head with cavity, formed by the multi-stage forging process, can comprise a loft angle ranging between <NUM> degrees and <NUM> degrees. In many embodiments, the loft angle of the club head is less than approximately <NUM> degrees, the loft angle of the club head is less than approximately <NUM>, degrees, the loft angle of the club head is less than approximately <NUM> degrees, the loft angle of the club head is less than approximately <NUM> degrees the loft angle of the club head is less than approximately <NUM> degrees, the loft angle of the club head is less than approximately <NUM> degrees, the loft angle of the club head is less than approximately <NUM> degrees, the loft angle of the club head is less than approximately <NUM> degrees, the loft angle of the club head is less than approximately <NUM> degrees, the loft angle of the club head is less than approximately <NUM> degrees, the loft angle of the club head is less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, less than approximately <NUM> degrees, or less than approximately <NUM> degrees. Further, in many embodiments, the loft angle of the club head is greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, greater than approximately <NUM> degrees, or greater than approximately <NUM> degrees. Further still, the multi-stage forging process can form multiple iron-type golf club heads with cavities, wherein the multiple iron-type golf club heads with cavities will comprise different lofts (aforementioned) to form a set of golf clubs (i.e., <NUM> iron, <NUM> iron, <NUM> iron, <NUM> iron, <NUM> iron, <NUM> iron, <NUM> iron, PW). In some embodiments, the multi-stage forging process can form multiple iron-type golf club heads with identically sized cavities, and different lofts to form a set of golf clubs.

Referring to <FIG>, the multi-stage forging method, comprises four stages: (<NUM>) a rough forging stage, in which intermediate club head body <NUM> is formed from a solid block billet (not shown); (<NUM>) a hot-pressing stage, in which a cavity <NUM> is formed in the intermediate club head body; (<NUM>) a precision forging stage wherein the intermediate club head body <NUM> is formed into a final golf club head <NUM>; (<NUM>) and an insert <NUM> or filling is placed within the cavity <NUM> of the golf club head body <NUM>. This multi-stage forging method allows a manufacturer to create a forged golf club head <NUM> with a deep undercut cavity <NUM>, from a single solid billet. In some embodiments, the multi-stage forging method can comprise a fifth stage (not shown), wherein a shaft and grip are attached to the golf club head body <NUM>, to form a golf club.

To begin the multi-stage forging method, a billeted material is provided. The billet is forged into an iron type golf club head and can be any one or more combination of the following: <NUM> 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 the billet. Further, the billet does not monolithically encase any other material. The one or more materials can be present on the surface of the billet, multiple surfaces of the billet, or a corner of the billet.

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 combination of the following: <NUM> 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 any other material. The multi-metal billet can comprise a base metal, with at least one different metal on the surface of the billet, at least one different metal on multiple surface of the billet, or at least one different metal on a corner of the billet.

The next step of the multi-stage forging process is to forge the billet to into an intermediate club head <NUM>. Referring to <FIG>, the intermediate club head body <NUM> is formed from a solid block billet that is rough forged by a first upper die <NUM> and a first lower die <NUM>. The first upper die <NUM> and first lower die <NUM> are shaped in a desired club head geometry. The solid block billet is heated to a desired temperature between <NUM> and <NUM>, making the billet very malleable, thus allowing forging to occur. In some embodiments, the desired billet temperature for rough forging is between <NUM> - <NUM>, <NUM> - <NUM>, <NUM> -<NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM>- <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>. In one embodiment, the desired billet temperature for rough forging is between <NUM> - <NUM>.

Once the solid block billet is heated to a desired temperature, the first upper die <NUM> and first lower die <NUM> apply a desired pressure to the billet, shaping the malleable billet to the shape of the desired geometry. The desired pressure that is applied to the billet by the first upper die <NUM> and the first lower die <NUM> is between <NUM> kN and <NUM> kN (<NUM> tons and <NUM> tons (<NUM> ton is equivalent to <NUM> pounds force)). In some embodiments, the desired pressure of the upper die <NUM> and lower die <NUM> is between <NUM> and <NUM> kN (<NUM> and <NUM> tons), <NUM> and <NUM> kN (<NUM> and <NUM> tons), <NUM> and <NUM> kN (<NUM> and <NUM> tons), <NUM> and <NUM> kN (<NUM> and <NUM> tons), <NUM> and <NUM> kN (<NUM> and <NUM> tons), <NUM> and <NUM> kN (<NUM> and <NUM> tons), <NUM> kN and <NUM> kN (<NUM> and <NUM> tons), <NUM> and <NUM> kN (<NUM> and <NUM> tons), <NUM> kN and <NUM> kN (<NUM> and <NUM> tons), <NUM> and <NUM> kN (<NUM> and <NUM> tons), <NUM> and <NUM> kN (<NUM> and <NUM> tons), and <NUM> and <NUM> kN (<NUM> and <NUM> tons). In some embodiments, the desired pressure of the upper die <NUM> and lower die <NUM> is between <NUM> and <NUM> kN (<NUM> tons and <NUM> tons). The extreme pressure of the upper die <NUM> and lower die <NUM>, quickly forms the malleable solid block billet to the desired geometry, thus maintaining the material and tensile properties of the metallic billet.

Referring to <FIG>, is a cross-sectional view of the upper die <NUM> and lower die <NUM> forming the intermediate club head body <NUM>, from the solid block billet. The intermediate club head body <NUM> that is formed from the rough forging comprises: a sole <NUM>, a top rail <NUM>, a strike face <NUM>, a back wall <NUM> of the strike face <NUM>, and a rear portion <NUM>. The strike face <NUM> has a heel end (not shown), a toe end (not shown), an upper region <NUM>, a lower region <NUM>, and a strike plane <NUM>. The strike plane <NUM> is parallel to the lower region <NUM> of the strike face <NUM> and is the desired plane that the strike face <NUM> will be bent to in a later step. The upper region <NUM> is opposite the back wall <NUM> of the strike face <NUM>, while the lower region <NUM> is opposite the rear portion <NUM>.

The rear portion <NUM> extends away from the strike face <NUM> and is adjacent the sole <NUM>. Further, the rear portion <NUM> comprises an upper edge <NUM>. The upper edge <NUM> is approximately perpendicular to the strike plane <NUM> and the lower region <NUM>. The upper edge <NUM> provides a surface, or ledge, to form a cavity within, in a later step. The rear portion <NUM> further comprises a nonlinear outer periphery <NUM>. The upper edge <NUM> spans the back wall of the strike face <NUM> from the heel end to the toe end. The nonlinear outer periphery <NUM> connects the sole <NUM> to the upper edge <NUM> of the rear portion <NUM>.

The back wall <NUM> of the strike face <NUM>, is adjacent the top rail <NUM> and the upper edge <NUM>, while parallel to the upper region <NUM> of the strike face <NUM>. The back wall <NUM> of the strike face <NUM> spans approximately from the heel end to the toe end.

The upper region <NUM> and lower region <NUM> of the strike face of the intermediate club head body <NUM>, are divided by an intersection plane <NUM>, wherein the intersection plane <NUM> is perpendicular to the lower region <NUM> of the strike face <NUM> and the strike plane <NUM>. The intersection plane <NUM> is also approximately parallel to the upper edge <NUM> of the rear portion <NUM>. The intersection plane <NUM> enables the forging of a cavity in the rear portion <NUM> of the intermediate club head body <NUM>. The intersection plane <NUM> is the plane that which the strike face <NUM> is bent about and is a bending point for creating the cavity <NUM> from the forged billet.

The intersection plane <NUM> runs approximately parallel to a ground plane <NUM>, wherein the ground plane <NUM> intersects the sole <NUM>. In most embodiments, the ground plane <NUM> is tangential to and parallel to the sole <NUM>. In some embodiments, the ground plane <NUM> intersects the sole <NUM> at an angle, not parallel to sole <NUM>.

Further still, the intersection plane <NUM> intersects the strike face of the intermediate club head body <NUM>, approximately bisecting the intermediate club head body <NUM>, dividing the upper region <NUM> and the lower region <NUM>. The intermediate club head body <NUM>, further comprises a height measured from the sole <NUM> to the top rail <NUM>. In most embodiments, the intersection plane <NUM> intersect the intermediate club head body <NUM> between <NUM>-<NUM>% of the height of the club head body <NUM>. In some embodiments, the intersection plane <NUM> intersects the club head body <NUM> at approximately <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>% of the height of the club head body <NUM>. In some embodiments, the intersection plane <NUM> intersects the club head body <NUM> between approximately <NUM>% - <NUM>%, <NUM>% - <NUM>%, <NUM>% - <NUM>%, <NUM>% - <NUM>%, or <NUM>% - <NUM>% of the height of the club head body <NUM> or any other suitable percentage height value in between those percentage height values, and can range from any one of those percentage height values to any other one of those percentage height values.

A clearance angle <NUM> is formed between the intersection plane <NUM> and the upper region <NUM> of the strike face <NUM>. The clearance angle <NUM> enables enough space for, for a second upper die <NUM> and a second lower die <NUM> to create a cavity <NUM> in the intermediate club head <NUM> in a later step. The clearance angle <NUM> can range between <NUM>° and <NUM>°. In some embodiments, the clearance angle <NUM> can range between <NUM>° and <NUM>°. In other embodiments, the clearance angle <NUM> can range between <NUM>° - <NUM>°, <NUM>° - <NUM>°, and <NUM>° - <NUM>°. In other embodiments, the clearance angle <NUM> can be <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, and <NUM>°.

Referring to <FIG>, the next step of the multi-stage forging method is the cavity <NUM> formation in the intermediate club head body <NUM>. Formation of the cavity <NUM> from the intermediate club head body <NUM> is accomplished by one or more of the following processes: hot pressing, machining, milling, drilling, or machine punching. The embodiment in <FIG>, illustrates the hot-pressing technique. The hot-pressing technique utilizes the second upper die <NUM> and the second lower die <NUM> (wherein the second upper die <NUM> and second lower die <NUM> are different in shape from the first upper die <NUM> and first lower die <NUM> of the rough forging stage) to precisely dimension a cavity <NUM> generally perpendicular to the upper edge <NUM> in the rear portion <NUM> of the intermediate club head body <NUM>. The second upper die <NUM> comprises a sharp geometry to penetrate through the upper edge <NUM> of the rear portion <NUM>, while the second lower die <NUM> holds the intermediate club head <NUM> at the desired clearance angle <NUM>, thus forming the cavity <NUM>.

The necessary temperature required to hot press the cavity <NUM> in the intermediate club head body <NUM> can range between <NUM> and <NUM>. In order to avoid strain hardening of the metal during deformation, this extreme heat is necessary for the hot-pressing process. If strain hardening occurs, the intermediate club head body <NUM> will become less malleable, making the cavity <NUM> harder to form. In some embodiments, the temperature required to hot press the cavity <NUM> in the intermediate club head body <NUM> can range between <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>. In one embodiment, the temperature required to hot press the cavity <NUM> in the intermediate club head body <NUM> can range between <NUM> and <NUM>.

Once the intermediate club head body <NUM> is heated to a desired temperature, the second lower die <NUM> apply a desired pressure to the intermediate club head body <NUM> maintaining shape (strike face <NUM>, bent about an intersection plane <NUM>, at a desired clearance angle <NUM>). The cavity <NUM> is then formed as the second upper die <NUM> applies a desired pressure and the sharp geometry penetrates through the upper edge <NUM> and within the rear portion <NUM>. The desired pressure that is applied to the intermediate club head body <NUM> by the second upper die <NUM> and the second lower die <NUM> is between <NUM> tons and <NUM> tons (<NUM> ton is equivalent to <NUM> pounds force). In some embodiments, the desired pressure of the second upper die <NUM> and second lower die <NUM> is between <NUM> - <NUM> tons, <NUM> - <NUM> tons, <NUM> - <NUM> tons, <NUM> - <NUM> tons, <NUM> - <NUM> tons, <NUM> - <NUM> tons, <NUM> - <NUM> tons, <NUM> - <NUM> tons, <NUM> - <NUM> tons, <NUM> - <NUM> tons, <NUM> - <NUM> tons, and <NUM> - <NUM> tons. In some embodiments, the desired pressure of the upper die <NUM> and lower die <NUM> is between <NUM> tons and <NUM> tons. The extreme pressure of the second upper die <NUM> and second lower die <NUM>, quickly forms the cavity <NUM> in the intermediate club head body <NUM>, thus maintaining the material and tensile properties of the metallic intermediate club head body <NUM>.

The cavity <NUM> formed by the methods described above, including hot-pressing, comprises a lower surface <NUM> and two interior surface walls <NUM>. The cavity <NUM> further comprises a surface area and a volume, that can provide a surface and region to affix an insert to, in a later step.

Further, the cavity <NUM> comprises a cavity axis <NUM>. The cavity axis <NUM> passes through a nadir of the cavity <NUM> lower surface <NUM>. The cavity axis <NUM> exactly bisects the cavity <NUM> and is equidistant from the cavity <NUM> interior surface walls <NUM>. The cavity <NUM> can be hot-pressed at an angle <NUM>, wherein the press angle <NUM> is measured from the cavity axis <NUM> to the intersection plane <NUM>. The press angle of the invention is <NUM>°, but as examples not covered by the appended claims (unless being <NUM>°) the press angle can range between <NUM>° and <NUM>°. In some examples, the press angle <NUM> can range between <NUM>° - <NUM>°, <NUM>° - <NUM>°, <NUM>° - <NUM>°, <NUM>° - <NUM>°, and <NUM>° - <NUM>° or any other suitable press angle <NUM> value in between those press angles <NUM> and can range from any one of those press angles <NUM> to any other one of those press angles <NUM>. In other examples, the press angle <NUM> can be <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, or <NUM>°. The press angle <NUM>, enables an insert to be affixed within the cavity <NUM> (in a later step) at a desired angle.

Further still, the cavity <NUM> can have a substantially triangular, rectangular, square, semi-circular, parabolic, or trapezoidal cross section. In some embodiments, the cavity <NUM> can comprise a different cross-section at a toe end of the cavity <NUM> and the heel end of the cavity <NUM>.

In some embodiments, the cavity <NUM> can have a volume of approximately <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, or any other suitable volume value in between those volume values, and can range from any one of those volume values to any other one of those volume values. In one embodiment, the volume of the cavity <NUM> is <NUM> cc. The volume of the cavity <NUM> can be substantially similar to the volume of an insert that is affixed within the cavity <NUM>.

In some embodiments, the cavity <NUM> can have a surface area ranging between approximately <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, <NUM>-<NUM><NUM>, or <NUM>-<NUM><NUM>. In other embodiments, the surface area of the cavity <NUM> can be any other suitable surface area value in between those surface area values and can range from any one of those surface area values to any other one of those surface area values. The surface area of the cavity <NUM> can be substantially similar to the surface area of an insert that is affixed within the cavity <NUM>.

In some embodiments, the cavity <NUM> can have a depth of approximately <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inches), <NUM>(<NUM> inches), <NUM> (<NUM> inches), <NUM> (<NUM> inch) or any other suitable depth value in between those depth values, and can range from any one of those depth values to any other on of those depth values. The depth of the cavity <NUM> can be substantially similar to a height of an insert that is affixed within the cavity <NUM>.

Following the cavity <NUM> formation in the intermediate club head body <NUM>, a final precision forging stage is performed to straighten the clearance angle <NUM> into a final golf club head.

After the hot-pressing of the cavity <NUM> into the intermediate club head body <NUM>, the club head body <NUM> is precision forged, wherein the strike face <NUM> is bent to a final angle <NUM>, wherein the final angle <NUM> is formed between the intersection plane <NUM> and the strike face <NUM>. The final angle <NUM> is approximately between <NUM>°-<NUM>° or <NUM>°, <NUM>°, <NUM>°, <NUM>°, or <NUM>°, thereby aligning the upper region <NUM> with the lower region <NUM> of the club heady body <NUM>. The intermediate club head body <NUM> is therefore forged further into a final golf club head <NUM>.

Referring to <FIG>, this precision forging stage comprises a third upper die <NUM> and a third lower die <NUM>, wherein the third upper die <NUM> and third lower die <NUM> are shaped in a desired geometry (wherein the second upper die <NUM>, the second lower die <NUM>, the first upper die <NUM>, and the first lower die <NUM> are different in shape from the third upper die <NUM> and third lower die <NUM>). The third upper die <NUM> and third lower die <NUM> apply a desired pressure to the intermediate club head body <NUM>, bending the upper portion <NUM> of the strike face <NUM> to align with the lower portion <NUM> of the strike face <NUM> within the strike plane <NUM>, thus bending the clearance angle <NUM> to a final angle <NUM> of approximately <NUM>° to the intersection plane <NUM>. In doing so, the intermediate club head body <NUM> is forged into a final golf club head <NUM>, as the strike face <NUM> is now continuously straight and can function for its intended purpose of striking a golf ball.

The intermediate club head body <NUM>, formed from the previous steps, must be heated to a desired temperature to bend the strike face <NUM> into the strike plane <NUM> in order to carry out this stage of the method. The intermediate club head body <NUM> is heated to a desired temperature between <NUM> and <NUM>. In some embodiments, the desired temperature of the intermediate club head body <NUM> for precision forging is between <NUM> - <NUM>, <NUM> - <NUM>, <NUM> -<NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM>- <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>, <NUM> - <NUM>. In one embodiment, the desired temperature of the intermediate club head body <NUM> for rough forging is between <NUM> - <NUM>.

Once the intermediate club head body <NUM> is heated to a desired temperature, the lower die <NUM> maintains the shape of the cavity and lower portion <NUM>, while the third upper die <NUM> presses against the back wall <NUM>. The third upper die <NUM> forces the upper portion <NUM> of the intermediate club head body <NUM> flush against the third lower die <NUM>, thus aligning the upper portion <NUM> with the lower portion, and therefore bending the clearance angle <NUM> to approximately <NUM>° to the intersection plane <NUM>. The desired pressure that is applied to the intermediate club head body <NUM> by the third upper die <NUM> and the third lower die <NUM> is between <NUM> tons and <NUM> tons (<NUM> ton is equivalent to <NUM> pounds force). In some embodiments, the desired pressure of the third upper die <NUM> and the third lower die <NUM> is between <NUM> - <NUM> tons, <NUM> - <NUM> tons, <NUM> - <NUM> tons, <NUM> - <NUM> tons, <NUM> - <NUM> tons, <NUM> - <NUM> tons, <NUM> - <NUM> tons, <NUM> - <NUM> tons, <NUM> - <NUM> tons, <NUM> - <NUM> tons, <NUM> - <NUM> tons, and <NUM> - <NUM> tons. In some embodiments, the desired pressure of the third upper die <NUM> and the third lower die <NUM> is between <NUM> tons and <NUM> tons. The extreme pressure of the upper die <NUM> and the third lower die <NUM>, maintains the form of the lower portion <NUM> and the cavity <NUM>, while pressing the upper region <NUM>, in line with the lower region <NUM>, and thus into a functioning strike face <NUM>. The strike face is then removed from the third upper die <NUM> and third lower die <NUM>, and set to cool in a room temperature environment, until it is safe to the touch.

Referencing <FIG>, following the three stages of forging the final golf club head <NUM>, an insert <NUM> can be affixed to the interior surface wall <NUM> and lower surface <NUM> of the cavity <NUM>. In some embodiments, nothing is placed with the cavity <NUM>. The insert <NUM> can be secured into the cavity <NUM> via adhesion, press-fitting, mechanical fastening, or any other suitable methods of securing the insert <NUM>. The insert <NUM> can be made of one or more elastomers. For example, the insert <NUM> can be made of nonferrous thermoplastic urethane, thermoplastic elastomeric polymer(s), hybrid plastics with a mix of ferrous particles or other alloy ferrous particles mixed into polyurethane or other elastomeric polymers. In other embodiments, the insert <NUM> can be a metal such as aluminum, steel, tungsten, forms of beads in polymer, powder metal in a suspension cured in a polymer, or other suitable metals, such as when the insert <NUM> is sintered or machined.

Further, the insert <NUM> can occupy the entire cavity <NUM> or a percentage of the cavity <NUM>. The percentage of the cavity <NUM> that is occupied can range between <NUM>% and <NUM>%. In some embodiments, the percentage of the cavity <NUM> that is occupied can range between <NUM>% - <NUM>%, <NUM>% - <NUM>%, <NUM>% - <NUM>%, <NUM>% - <NUM>%, <NUM>% - <NUM>%, <NUM>% - <NUM>%, <NUM>% - <NUM>% - <NUM>%, <NUM>% - <NUM>%, <NUM>% - <NUM>%. In one embodiment, the percentage of the cavity <NUM> that is occupied ranges between <NUM>% - <NUM>%.

In many embodiments, the insert <NUM> can have a weight that advantageously can be configured to reinforce the strike face <NUM>, to beneficially minimize undesirable impact vibration, and/or to establish or adjust the golf club swing weight during assembly. For example, the insert <NUM> can have a mass of approximately <NUM> to approximately <NUM>. For example, tuning element <NUM> can have a mass of approximately <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or any other suitable mass in between those mass values, and can range from any one of those mass values to any other one of those distance values. For example, in some embodiments, the insert <NUM> can have a mass of approximately <NUM> to approximately <NUM>.

In several embodiments, the insert <NUM> can have a density of approximately <NUM>/cc to approximately <NUM>/cc. For example, the insert <NUM> can have a density of approximately <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, <NUM>/cc, or any other suitable density value in between those density values, and can range from any one of those density values to any other one of those density values.

In reference to <FIG>, the final golf club <NUM>, formed by the aforementioned manufacturing process, is a forged iron type golf club head with a cavity <NUM>. The final golf club <NUM> comprises: a hosel <NUM>, a top rail <NUM>, a sole <NUM>, a toe region <NUM>, a heel region <NUM>, a rear <NUM>, a strike face <NUM> (not shown), a cavity <NUM>, and an insert <NUM>.

Referring to <FIG>, the multi-stage forging method, comprises four stages: (<NUM>) a rough forging stage, in which intermediate club head body <NUM> is formed from a solid block billet (not shown); (<NUM>) a hot-pressing stage, in which a cavity <NUM> is formed in the intermediate club head body; (<NUM>) a precision forging stage wherein the intermediate club head body <NUM> is formed into a final golf club head <NUM>; (<NUM>) and an insert <NUM> or filling is placed within the cavity <NUM> of the golf club head body <NUM>. This multi-stage forging method allows a manufacturer to create a forged golf club head <NUM> with a deep undercut cavity <NUM>, from a single solid billet. However, in this embodiment, the multi-stage forging method comprises a fifth stage (not shown), wherein a shaft and grip are attached to the golf club head body <NUM>, to form a golf club. The multi-stage forging process is then repeated to form multiple iron-type golf club heads with cavities, wherein the multiple iron-type golf clubs with cavities will comprise different lofts (aforementioned) to form a set of golf clubs (i.e., <NUM> iron, <NUM> iron, <NUM> iron, <NUM> iron, <NUM> iron, <NUM> iron, <NUM> iron, PW).

In some embodiments, the multi-stage forging process can form multiple iron-type golf club heads with identically sized cavities, and different lofts to form a set of golf clubs. With identically sized cavities, the inserts that are affixed to each golf club head, all have an exact same volume, but can have varying densities and therefore varying masses. This variability allows the inserts for each golf club head of the golf club set to have different swing weights and/or different CG locations. Furthermore, this make the manufacturing of the inserts more efficient, since only the material (therefore changing the density) of the insert needs to be changed, in order to change the weighting of the insert, for each club head. Inserts are produced at different weights in order to account for manufacturing tolerances (i.e., if a golf club head is supposed to weight <NUM> grams, but only weighs <NUM> grams, then a <NUM> gram weight can be added to the golf club head cavity).

The aforementioned method of manufacturing produces can produce of set of forged iron-type golf clubs with similar sized cavities. In reference to <FIG>, the final golf club head <NUM> formed by the method of manufacturing comprises a hosel <NUM>, a top rail <NUM>, a sole <NUM>, a toe region <NUM>, a heel region <NUM>, a rear <NUM>, a strike face <NUM> (not shown), a cavity <NUM>, an insert <NUM>, a shaft (not shown), and a grip (not shown). The set of forged iron-type golf clubs can comprise <NUM> golf clubs, <NUM> golf clubs, <NUM> golf clubs, <NUM> golf clubs, <NUM> golf clubs, <NUM> golf clubs, <NUM> golf clubs, <NUM> golf clubs, or <NUM> golf clubs.

Each golf club of the forged iron-type golf club set can comprise cavity <NUM> having a volume of approximately <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, <NUM> cc, or any other suitable volume value in between those volume values, and can range from any one of those volume values to any other one of those volume values. In one embodiment, the volume of the cavity <NUM> is <NUM> cc. The volume of the cavity <NUM> can be substantially similar to the volume of an insert that is affixed within the cavity <NUM>. The volume can also be approximately identical for each golf club of the forged iron-type golf club set.

The enclosed manufacturing process is an improvement over the current industry standard. The multi-stage forging process utilizes a dual stage forging process, in which an intermediate club head <NUM> is formed with a strike face <NUM> that is bent at a clearance angle <NUM>, enabling a cavity <NUM> to be hot pressed opposite of the strike face <NUM>. The strike face <NUM> is then bent back into a functional strike face <NUM>, and a final golf club head <NUM> is created. This bent strike face <NUM> technique allows a manufacturer to create a forged golf club head body <NUM> with a deep undercut cavity <NUM>, from a single solid billet.

By creating an entirely forged golf club head <NUM>, with a deep undercut cavity <NUM>, a tighter grain structure of the golf club head is achieved. With a tighter grain structure, the durability of the golf club head <NUM> is improved. Forging the golf club head <NUM> with a deep undercut cavity <NUM> from the billet process, allows a more durable cavity style iron than current cast cavity irons, because of a tighter and more consistent grain structure.

Further, this multi-stage forging method is 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 method requires little to no machining. Thus, the forging process is more repeatable since there is less uncertainty involved from hand machining techniques. Furthermore, with less machining processes involved in the golf club head production, the enclosed invention lowers the overall cost of producing a premium golf club head with an undercut cavity.

The golf club head created from this multi-stage forging method, is comparable in feel and performance to a casted golf club head of similar geometry. Since the forged iron comprises a stronger composition, the strike face is able to be made thinner, thereby increasing the flexibility of the strike face. The forged iron thus increases ball speed and workability (shot bend) over a casted golf club head of similar geometry, while maintaining or improving spin rates, sound characteristics, and feel characteristics.

Replacement of one or more claimed elements constitutes reconstruction and not repair. Additionally, benefits, other advantages, and solutions to problems have been described with regard to specific embodiments. The benefits, advantages, solutions to problems, and any element or elements that may cause any benefit, advantage, or solution to occur or become more pronounced, however, are not to be construed as critical, required, or essential features or elements of any or all of the claims.

As the rules to golf may change from time to time (e.g., new regulations may be adopted or old rules may be eliminated or modified by golf standard organizations and/or governing bodies such as the United States Golf Association (USGA), the Royal and Ancient Golf Club of St. Andrews (R&A), etc.), golf equipment related to the apparatus, methods, and articles of manufacture described herein may be conforming or non-conforming to 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 conforming or non-conforming golf equipment. The apparatus, methods, and articles of manufacture described herein are not limited in this regard.

Claim 1:
A forged golf club head (<NUM>) comprising:
a club head body comprising a sole (<NUM>), a top rail (<NUM>), a strike face (<NUM>), a back wall (<NUM>) of the strike face (<NUM>), and a rear portion (<NUM>);
wherein the strike face (<NUM>) comprises a heel end, a toe end, an upper region (<NUM>), and a lower region (<NUM>);
wherein the rear portion (<NUM>) of the body has an upper edge (<NUM>) and a nonlinear outer periphery (<NUM>);
wherein the strike face (<NUM>) comprises a strike plane (<NUM>) that is coplanar to the strike face (<NUM>);
a cavity (<NUM>) located between the rear portion (<NUM>) and the back wall (<NUM>) of the strike face (<NUM>) and extending along a cavity axis (<NUM>);
wherein the club head body is forged from a single solid billet; characterized in that:
the cavity (<NUM>) comprises a volume of between <NUM> cc and <NUM> cc;
the cavity axis (<NUM>) is parallel to the strike plane (<NUM>); and
the cavity (<NUM>) is formed during a multi-stage forging.