US20220379367A1

US20220379367A1 - Forged golf club head with improved scorelines

Info

Publication number: US20220379367A1
Application number: US17/505,230
Authority: US
Inventors: Kevin Tassistro
Original assignee: Acushnet Co
Current assignee: Acushnet Co
Priority date: 2021-05-27
Filing date: 2021-10-19
Publication date: 2022-12-01
Also published as: US20240051016A1

Abstract

A forged golf club head is disclosed. More specifically, the present invention discloses a forged golf club head with an improved scoreline profile that not only has improved precision, but also has an improved geometry to help enhance the performance of the golf club head.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation-In-Part (CIP) of U.S. patent application Ser. No. 17/332,103, filed on May 27, 2021, the disclosure of which is incorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates generally to iron type golf club heads with improved scoreline profile. More specifically, the present invention relates to forged iron type golf club heads with forged scorelines that exhibit an improved precision and geometry to help enhance the performance of the golf club head itself.

BACKGROUND OF THE INVENTION

The process of forging raw metal into work pieces of specific shapes is one of the oldest known method of manufacturing. In fact, blacksmiths have been forging weapons using hammer and anvil as early as the 12^thcentury. Forging of metal is generally perceived to yield a stronger piece than an equivalent cast part, as the metal is shaped during the forging process, while allowing its internal grain structure to follow the general shape of the part. Casting, on the other hand, is the manufacturing process in which liquid metal is usually poured into a mold, which contains a hollow cavity of the desired shape, then allowed to solidify.
When it comes to manufacturing golf club heads, especially iron type golf club heads, golf club engineers have utilized both methods to create golf club heads, both with extreme levels of success. However, the affinity of the specific golfing demographic's infatuation with forged golf club heads constantly drive the golf club engineers to find ingenious ways to achieve better performance using forging as a preferred method of manufacture.
U.S. Pat. No. 3,825,991 to Cornell illustrates one of the earlier patents relating to the improvement of forging in golf club heads, which in this case, relates specifically relates to making a golf club head out of two pieces, of which only the blade portion is forged to create the desired characteristic. The hosel portion can be formed separately, and can be machined to have a threaded engagement mechanism.
U.S. Pat. No. 2,931,098 to Johnson, back in 1960, illustrates one of the earlier attempts to manufacture a golf club head using a die casting operation combined with a cold rolling of the striking face in a direction parallel to the sole of head, combining semblances of both forging and casting in a golf club head.
Despite the advancements above relating to improvements in golf club forgings, one of the drawbacks of forging a golf club head is its inability to generate precise scorelines, which is a key feature in generating spin in an iron type golf club head.
In order to address this issue, golf club technology generally machine scorelines into a golf club head after the formation of the golf club head, regardless of whether it was created via a forging or a casting process. U.S. Pat. No. 8,845,455 to Ban et al. illustrates this by disclosing a golf club head wherein the head includes a recessed portion for the cutting start of each scoreline, which is formed at one end or each of both ends of the scoreline in the longitudinal direction.
These secondary machining operations, although capable of providing more precision to the scoreline geometry, unnecessarily add to the manufacturing cost of the golf club head. Moreover, these secondary machining operations are also incapable of creating improved groove geometries that could even be asymmetrical to further improve the performance of a golf club head.
Hence, it can be seen from above, despite all the development in creating iron type golf club heads, golf club designers are forced to pick between precision or manufacturability, with the former coming at a significant price increase on top of the latter. The present invention addresses that issue by creating a golf club head with improved forged scorelines that not only precise, but also capable of creating geometries that are previous not achievable via traditional secondary machining techniques.

BRIEF SUMMARY OF THE INVENTION

In one aspect of the present invention is a method of forging a golf club head comprising the steps of providing a raw forging blank, hot pre-forging the raw forging blank to create a golf club head without scorelines, cold pre-forging the golf club head to create a rough scoreline pattern, polishing a face of the golf club head to remove an excess material after the cold pre-forging step, and final forging the golf club head to create a final scoreline pattern, wherein at least one scoreline of the final scoreline pattern further comprises of a toe terminus profile, a heel terminus profile, and a face centerline, defined as a center point between the toe most portion of the at least one scoreline and a heel most point of the at least one scoreline. The toe terminus profile of the at least one scoreline profile is different from the heel terminus of the at least one scoreline.
In yet another aspect of the present invention the forged golf club head has a Heel to Toe Terminus Slope Ratio of greater than about 6, the Heel to Toe Terminus Slope Ratio defined as;
$Heel to Toe Terminus Slope Ratio = \frac{Heel Terminus Profile Slope}{Toe Terminus Profile Slope} .$
These and other features, aspects and advantages of the present invention will become better understood with references to the following drawings, description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features and advantages of the invention will be apparent from the following description of the invention as illustrated in the accompanying drawings. The accompanying drawings, which are incorporated herein and form a part of the specification, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention.

FIG. 1 of the accompanying drawings shows a toe side view of a golf club head in accordance with an exemplary embodiment of the present invention;

FIG. 2 of the accompanying drawings shows a face on view of a golf club head in accordance with an exemplary embodiment of the present invention;

FIG. 3 a of the accompanying drawings shows face on view of one scoreline in accordance with a prior art golf club head;

FIG. 3 b of the accompanying drawings shows a cross-sectional view of one scoreline in accordance with a prior art golf club head taken along cross-sectional line A-A′ shown in FIG. 2 ;

FIG. 3 c of the accompanying drawings shows a partial enlarged cross-sectional view of a prior art scoreline highlighting circular region I in FIG. 3 b;

FIG. 3 d of the accompanying drawings shows a partial enlarged cross-sectional view of a prior art scoreline highlighting circular region II in FIG. 3 b;

FIG. 4 a of the accompanying drawings shows a face on view of one scoreline in a golf club head in accordance with an exemplary embodiment of the present invention;

FIG. 4 b of the accompanying drawings shows a cross-sectional view of one scoreline in accordance with an exemplary embodiment of the present invention;

FIG. 4 c of the accompanying drawings shows a partial enlarged cross-sectional view of a scoreline in accordance with an exemplary embodiment of the present invention highlighting circular region III in FIG. 4 b;

FIG. 4 d of the accompanying drawings shows a partial enlarged cross-sectional view of a scoreline in accordance with an exemplary embodiment of the present invention highlighting circular region IV in FIG. 4 b;

FIG. 5 of the accompanying drawings shows a flow chart of a method used to create the current inventive golf club head in accordance with the present invention;

FIG. 6 a of the accompanying drawings shows a face on view of one scoreline in a golf club head in accordance with an exemplary embodiment of the present invention;

FIG. 6 b of the accompanying drawings shows a cross-sectional view of one scoreline in accordance with an exemplary embodiment of the present invention;

FIG. 6 c of the accompanying drawings shows a partial enlarged cross-sectional view of a scoreline in accordance with an exemplary embodiment of the present invention highlighting circular region V in FIG. 6 b;

FIG. 6 d of the accompanying drawings shows a partial enlarged cross-sectional view of a scoreline in accordance with an exemplary embodiment of the present invention highlighting circular region VI in FIG. 6 b;

FIG. 7 a of the accompanying drawings shows a face on view of one scoreline in a golf club head in accordance with an exemplary embodiment of the present invention;

FIG. 7 b of the accompanying drawings shows a cross-sectional view of one scoreline in accordance with an exemplary embodiment of the present invention;

FIG. 7 c of the accompanying drawings shows a partial enlarged cross-sectional view of a scoreline in accordance with an exemplary embodiment of the present invention highlighting circular region VII in FIG. 7 b;

FIG. 7 d of the accompanying drawings shows a partial enlarged cross-sectional view of a scoreline in accordance with an exemplary embodiment of the present invention highlighting circular region VIII in FIG. 7 b;

FIG. 8 a of the accompanying drawings shows a face on view of one scoreline in a golf club head in accordance with an exemplary embodiment of the present invention;

FIG. 8 b of the accompanying drawings shows a cross-sectional view of one scoreline in accordance with an exemplary embodiment of the present invention;

FIG. 8 c of the accompanying drawings shows a partial enlarged cross-sectional view of a scoreline in accordance with an exemplary embodiment of the present invention highlighting circular region IX in FIG. 8 b ; and

FIG. 8 d of the accompanying drawings shows a partial enlarged cross-sectional view of a scoreline in accordance with an exemplary embodiment of the present invention highlighting circular region X in FIG. 8 b.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is of the best currently contemplated modes of carrying out the invention. The description is not to be taken in a limiting sense but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims.
Various inventive features are described below that can each be used independently of one another or in combination with other features. However, any single inventive feature may not address any or all of the problems discussed above or may only address one of the problems discussed above. Further, one or more of the problems discussed above may not be fully addressed by any of the features described below.
FIG. 1 of the accompanying drawings shows a toe side view of a golf club head 100 in accordance with an exemplary embodiment of the present invention. The golf club head 100 shown here is mainly comprised out of a hosel portion 102 and a body portion 104. The loft angle α of the golf club head 100 is also shown in FIG. 1 , as the angle created by the frontal planar portion of the striking face 106 as well as the hosel bore axis 108. Finally, FIG. 1 of the accompanying drawings also shows a Center of Gravity CG location, illustrating an ancillary feature of the present invention. More information regarding the precise CG location of the golf club head may be found in U.S. Patent Publication 2019/02262674 to Tassisstro et al., filed on May 8, 2019, the disclosure of which is incorporated by reference in its entirety.
FIG. 2 of the accompanying drawings shows a frontal face on view of a golf club head 200 in accordance with the present invention. Face on view, as it is commonly known in the industry, refers to a view of the golf club head 200 that is perpendicular to the loft angle α (shown previously in FIG. 1 ), by tilting the entire golf club head 200 forward. In this face on view of the golf club head 200, the striking face 106 is shown more clearly with a plurality of scorelines 212 that run along a heel to toe direction on the face. In this face on view, the visual geometry of the scorelines can be shown more clearly when the scorelines are enlarged, and cross-sectional geometry of the scorelines can be shown more clearly when a cross-sectional view of the golf club head 200 is taken along cross-sectional lines A-A′. Finally, FIG. 2 of the accompanying drawings shows a face centerline 211 of the scorelines 212, which will be helpful in defining scoreline symmetry in subsequent figures. The face centerline 211, as defined in the current invention, refers to the center point between the toe most portion of the scoreline and the heel most portion of the scoreline.
FIGS. 3 a through 3 d shows a face on view, a cross-sectional view, and two enlarged cross-sectional views of a scoreline 312 in the striking face 306 in accordance with a prior art golf club head 300. This prior art golf club head 300 illustrates one of the most consistent methodologies in creating a precise scoreline via horizontal machining. Using horizontal machining allows for a more precise scoreline profile and geometry and is usually accompanied by a unique groove profile and geometry that is indicative of such a machining technique. More information about this horizontal machining process known as “spin milling” in the industry can be found in U.S. Pat. No. 7,273,422 to Vokey et al., the disclosure of which is incorporated by reference in its entirety.
FIG. 3 a shows a face on view of a prior art scoreline 312 that spans the striking face 306 (shown in FIG. 3 b ) of the club head (shown in FIG. 3 b ) from heel to toe. At one end of the scoreline 312, the toe terminus profile 314 exists at a toe end of the scoreline 312; while at the other end of the scoreline 312 exists the heel terminus profile 316. Both the toe terminus profile 314 and the heel terminus profile 316 have identical geometries because the same cutter is used to cut this scoreline 312 as it rotates perpendicular to the striking face 306 (shown in FIG. 3 b ). Alternatively speaking, it can be said that the scoreline 312 is symmetrical about the face centerline 311, with the toe terminus profile 314 and the heel terminus profile 316 being mirror images of one another.
FIG. 3 b of the accompanying drawings shows a cross-sectional view of a prior art golf club head 300 along cross-sectional line A-A′ shown in FIG. 1 . The cross-sectional view of the golf club head 300 shown here in FIG. 3 b allows for the internal profile and geometry of the scoreline 312 on the striking face 306 to be shown more clearly. Unfortunately, due to the inherent length of the scoreline 312 horizontally compared to the geometry of the toe and heel terminus profiles 314 and 316. Thus, in order to provide better visualization of the terminus end profiles, the toe terminus end 314 cross-sectional profile, highlighted by circular region I, is enlarged in FIG. 3 c ; while the heel terminus end's 316 cross-sectional profile is highlighted by circular region II and shown enlarged in FIG. 3 d.
FIG. 3 c shows an enlarged cross-sectional view of a toe terminus profile 314 of a scoreline 312 in accordance with a prior art golf club head 300 (shown in FIG. 3 b ). In this enlarged cross-sectional view shown in FIG. 3 c , we can see that the toe terminus profile 314 of the scoreline 312 contains a small radius of curvature 324 that generally matches the cutter used to machine the scoreline 312 itself. The gradual radius of curvature 324 of approximately 0.3 inches allows horizontal cutter to engage the striking face to create the precise scoreline previously mentioned.
FIG. 3 d shows an enlarged cross-sectional view of a heel terminus profile 316 of a scoreline 312 in accordance with a prior art golf club head 300 (shown in FIG. 3 b ). It should be noted that this heel terminus profile 316 is a mirror image of the toe terminus profile 314 shown previously in FIG. 3 c , which makes sense because the same cutter is used to form the entirety of the scoreline 312. As previously mentioned, it can be said that the scoreline profile is symmetrical about the face centerline 311 (shown in FIG. 3 b ), thus the radius of curvature 326 of the heel terminus profile 316 is also approximately 0.3 inches.
FIGS. 4 a through 4 d shows a face on view, a cross-sectional view, and two enlarged cross-sectional views of a scoreline 412 in the striking face 406 in accordance with a golf club head 400 in accordance with an exemplary embodiment of the present invention. It should be noted here that the scoreline 412 in accordance with this embodiment, because it is no longer machined using a cutter, can take on asymmetric profiles along the face centerline 411. More specifically, as shown in FIG. 4 a the toe terminus profile 414 in this embodiment can have a completely different profile compared to the heel terminus profile 416 not only in terms of a difference in the radius of curvature, but also could have a completely different geometry, both without departing form the scope and content of the present invention. To achieve asymmetric profile along the face centerline 411, the current inventive scoreline 412 is formed using an improved multi-step forging process, the details of which will be discussed later when discussing FIG. 5 .
FIG. 4 a of the accompanying drawings shows a face on view of a scoreline in accordance with an exemplary embodiment of the present invention. A closer look at the toe terminus profile 414 and the heel terminus profile 416 will show that the two profiles are completely different. Although a comparison of the enlarged cross-sectional view of this scoreline 412 will show in more detail how the toe terminus profile 414 has a more gradual radius compared to a sharp taper on the heel terminus profile 416, the present face on view already illustrates the difference between the two ends of the scorelines 412. Having a different and asymmetrical toe terminus profile 414 and heel terminus profile 416 is critical to the present invention not only because it is unachievable using the traditional prior art machining techniques, but also because
FIG. 4 b of the accompanying drawings shows a cross-sectional view of a golf club head 400 in accordance with an exemplary embodiment of the present taken along cross-sectional line A-A′ as shown in FIG. 2 . Similar to the discussion previously this overall cross-sectional view is not detailed enough to show the terminal ends of the scoreline 412 on the striking face 406. Circular regions III and IV are highlighted to show the regions of the toe terminus profile 414 and heel terminus profile 416 in more detail.
FIG. 4 c of the accompanying drawings shows an enlarged cross-sectional view of a toe terminus profile 414 as identified by circular region III shown in FIG. 4 b . In this enlarged cross-sectional view shown in FIG. 4 c , we can see that the toe terminus profile 414 of the scoreline 412 contains a radius of curvature 424 that can be any radius of curvature, and does not need to match the radius of curvature of any cutter, as the scoreline 412 is forged. In this exemplary embodiment of the invention, the radius of curvature 424 is greater than 0.3 inches but could easily be less than 0.3 inches without departing from the scope and content of the present invention. However, it is the comparison of the difference in the toe terminus profile 414 and the heel terminus profile 416, shown later in FIG. 4 d , that is the key to this embodiment.
FIG. 4 d of the accompanying drawings shows an enlarged cross-sectional view of a heel terminus profile 416 as identified by circular region IV shown in FIG. 4 b . In this enlarged cross-sectional view shown in FIG. 4 d , we can see that the heel terminus profile 416 of the scoreline 412 is completely different than the toe terminus profile 414 in that it contains a chamfered profile 426 that is not radiused at all. The chamfer profile 426, in this embodiment of the present invention, may generally have an angle β of between about 1 degree to about 89 degrees, more preferably between about 10 degrees to 80 degrees, and most preferably between about 15 degrees to 45 degrees, all without departing from the scope and content of the present invention. Once again, the current inventive forging process allows the present invention to not only create a completely different toe and heel terminus profile 416, but allow the terminus profile 414 to deviate from a radius profile that was previously tied to the cutter radius into a chamfered profile.
Another key feature to highlight here regarding the difference in toe terminus profile 414 and the heel terminus profile 416 is the more gradual transition at the toe terminus profile 414, compared to the heel terminus profile 416. This design is intentional because as the golf club is swung in a golf swing, the rotational that the golf club head 400 forces debris caught in the scoreline towards the toe terminus profile 416. Creating a more gradual transition at the toe terminus profile 416 allows greater ease of the debris to be channeled out of the scoreline through that opening, further improving the performance of the golf club head 400.
To quantify this gradual toe terminus profile 414 that could be arcuate, chamfered, or even alternate shapes, the present invention defines the gradualness merely with a slope of change. This slope of change of either the toe terminus profile 414 or the heel terminus profile 416 is defined in accordance with the standard definition of a slope of anything, which is the rise over run of either profile. In FIG. 4 c , the rise is defined as distance d1, which in the current exemplary embodiment is less than about 0.8 mm, more preferably less than about 0.6 mm, and most preferably less than about 0.4 mm. The run, on the other hand, as shown in FIG. 4 c , as shown as distance d2, which in the current exemplary embodiment is greater than about 2.5 mm, more preferably greater than about 3 mm, and most preferably greater than about 3.2 mm. Thus, it can be said that the gradual toe terminus profile 414 of the scoreline 412 in accordance with the present invention may generally have a slope of less than about 0.25, more preferably less than about 0.20, and most preferably less than about 0.15.
However, the toe terminus profile 414 here only paints half the story, because the heel terminus profile 416 in accordance with the present invention will have a much steeper transition compared to the toe terminus profile 414. This steeper transition in the heel terminus profile 416 will further force debris to channel out of the toe terminus profile 414 instead of the heel terminus profile 416, which is the preferred side to channel debris. The steep heel terminus profile 416 of the scoreline 412 in accordance with the present invention may generally have a slope of greater than about 1.5, more preferably greater than about 1.75, and most preferably greater than about 2.0.
The differing slope between the toe terminus profile 414 and the heel terminus profile 416 can also be quantified as a relationship to one another defined here as Heel to Toe Terminus Slope Ratio, as illustrated by Equation (1) below:
$\begin{matrix} Heel to Toe Terminus Slope Ratio = \frac{Heel Terminus Profile Slope}{Toe Terminus Profile Slope} & Eq . (1) \end{matrix}$
The Heel to Toe Terminus Slope Ratio in accordance with the present invention may generally be greater than about 6, more preferably greater than about 8.75, and most preferably greater than about 13.
FIG. 5 of the accompanying drawings shows a flow chart of how the current invention utilizes a multi-step forging process to achieve the scoreline profiles in accordance with the present invention with enhanced precision. This inventive process, although may appear simple on its surface, recognizes the inability of the current forging techniques to create precise scorelines without “shouldering”. “Shouldering”, as it is known in the industry, refers to excess material that flows into undesirable portions of the golf club head around the scorelines that often results in a forging process. In order to address this “shouldering” issue, which prevents the forging process from achieving precise scorelines, the present invention has separated the forging process into three separate forging steps.
In step 532, the golf club head begins as a raw forging blank, which in most situations, is circular type billet. Different methodologies for forging a golf club head can be found in U.S. Pat. No. 8,926,451 to Deshmukh et al., the disclosure of which is which is incorporated by reference in its entirety. In the next step 534, the raw forging blank is heated and hot pre-forged to create a golf club head without scorelines. This step 534 is the first pre-forging step in a series of multiple forging steps to create the golf club head with precise scorelines as outlined previously. During this hot pre-forging step 534, the entire billet workpiece is heated and pre-forged to create the shape of a golf club head. Scorelines, however, are not formed in this step because of the amount of precision required for scorelines are not conducive to hot forging.
Once the pre-forging is completed in step 534, a step of flattening could be used here to create a flat face surface to prepare for the next step 536 that creates the scorelines. Flattening of the face could be achieved via machining, stamping, pressing, or any other methods capable of achieving a flat surface without departing from the scope and content of the present invention. The machining step can be accomplished via fly cutting, end milling, or any other types of machining operation all without departing from the scope and content of the present invention. Although in the present embodiment the flattening step is contemplated to occur between step 534 and step 536 before the cold forging occurs, it can also occur between steps 536 and 538 before the polishing occurs, or even between steps 538 and step 540 before the final forging step, all without departing from the scope and content of the present invention. In fact, the flattening step can occur once, twice, three times, or any number of times along the entire process, if there are any rework required, also all without departing from the scope and content of the present invention.
In order to begin forming scorelines, the current method, in step 536, cold pre-forges the golf club head to create rough scorelines. The word cold is used here to describe this step 536 because the golf club head is not heated during this process, which results in less flow of the material, minimizing the amount of desirable excess material around the scorelines themselves known as “shouldering” that was previously described. However, noticed that some “shouldering” still exists in the golf club after this step, and it could be a great detriment to the precision of the scorelines themselves. In order to address this issue, the present invention creates two additional steps in the forming process that were previously ignored.
In step 538, after the golf club head has been cold pre-forged to create rough scorelines in step 536, the excess material known as “shouldering” is removed via a polishing step that is specifically aimed at removing this excess material. This step is critical to the present invention because it specifically addresses a need in the process that was previously lacking. Once the polishing of the face has been completed, the golf club head goes through a final forging step in step 540.
In step 540, which is the final step in this process, the golf club head is forged again, this time also in a cold forging context, to create the final scoreline shape, profile, and geometry. Due to the fact that the excess material is removed in the polishing step in step 538, this final step 540 is capable of achieving the precise scoreline profile without the need of a secondary machining technique.
Once step 540 has been completed, the golf club with final scorelines have technically been formed. However, in precision machining processes such as these, inspection of the final geometry is critical to the performance of the golf club head. Hence, in step 542, the golf club head with final scorelines is inspected to ensure that it meets the specifications. If the golf club head fails the inspection and does not meet the design specifications, then the golf club is returned to step 538 to be repeated in the process. However, if the golf club head does pass inspection, then the manufacturing process truly ends at step 544.
FIGS. 6 a through 6 d show a face on view, a cross-sectional view, and two enlarged cross-sectional views of a scoreline 612 in the striking face 606 of a golf club head 600 in accordance with another exemplary embodiment of the present invention. In the face on view of the scoreline 612 shown in FIG. 6 a , the toe terminus profile 614 is once again different from the heel terminus profile 616, meaning that it is asymmetrical about the face centerline 611. A closer look at the cross-sectional profile of the golf club head 600 in accordance with this exemplary embodiment of the present invention shown in FIG. 6 b , which is taken along cross-sectional line A-A′ shown in FIG. 2 , we can see that circular regions V and VI focusing on the toe terminus profile 614 and heel terminus profiles 616 respectively.
FIGS. 6 c and 6 d show the enlarged cross-sectional views of the toe terminus profile 614 and the heel terminus profile 616, as highlighted by circular region V and VI respectively, shown in FIG. 6 b . Once again, the key feature to notice here is that the toe terminus profile 614 is different from the heel terminus profile 616. In this embodiment, the toe chamfer 624 shape is different from the heel chamfer 626 shape in terms of its chamfer angle, despite both ends of the scoreline 612 are chamfered in shape. More specifically, both the toe terminus profile 614 and the heel terminus profile 716 have different slopes form one another in the ranges previously outlined for their perspective locations, thus yielding a same Heel to Toe Terminus Slope Ratio as previously outlined above.
FIGS. 7 a through 7 d shows a face on view, a cross-sectional view, and two enlarged cross-sectional views of a scoreline 712 of a golf club head 700 in accordance with another exemplary embodiment of the present invention. In the face on view of the scoreline 712 shown in FIG. 7 a , we can once again see that the toe terminus profile 714 is different from the heel terminus profile 716, meaning that it is asymmetrical about the face centerline 711. It should be noted here that the present embodiment illustrates a circular toe terminus profile 714 from this face on view, which differs from the radius and/or chamfered profile shown in previous embodiments. In order to examine the slope of the transition out of the scorelines 712, a cross-sectional view of the golf club head 700 is taken along cross-sectional line A-A′ shown in FIG. 2 . Finally, circular regions VII and VIII are also highlighted here to enlarge the cross-sectional profiles of the scoreline 712 at the toe terminus profile 714 and the heel terminus profile 716.
FIGS. 7 c and 7 d show the enlarged cross-sectional views of the toe terminus profile 714 and the heel terminus profile 716 highlighted by circular regions VII and VIII respectively, shown in FIG. 7 b . Similar to previous embodiments, we can see that the toe terminus profile 714 is different from the heel terminus profile 716 in this cross-sectional view in addition to the face on view previously shown. The toe terminus profile 714 is of a circular region, having a radius of curvature 724 of about 0.03 inches, while the heel terminus profile 716 has a chamfer angle of between about 1 degree to about 89 degrees, more preferably between about 10 degrees to 80 degrees, and most preferably between about 15 degrees to 45 degrees, all without departing from the scope and content of the present invention.
FIG. 8 a through 8 d show a face on view, a cross-sectional view, and two enlarged cross-sectional views of a scoreline 812 in the striking face 806 of the golf club head 800 in accordance with another exemplary embodiment of the present invention. In this face on view of the scoreline 812, we can see that the scoreline 812 is technically symmetric about the face centerline 811 but is asymmetric about a different axis that spans along the length of the scoreline 812 itself. This alternate asymmetric shape may further enhance the ability of the scoreline to channel away debris from the scoreline by allowing the excess debris to converge on a specific location at a terminal end of the scoreline.
The full scale cross-sectional view of the scoreline 812 shown in FIG. 8 b as well as the enlarged cross-sectional views of the toe terminus profile 814 and heel terminus profile 816 shown in FIGS. 8 c and 8 d respectively, are provided to show how the scorelines 812 look, but do not illustrate any of the asymmetry due to the axis of asymmetry not being along face centerline 811.
It should be noted here that although the prior discussion discuss various features of the improved scoreline that can be forged to create asymmetry in various ways, the present invention is not limited to the illustrated embodiments. In fact, any combination of the types of asymmetry in terms of terminus profile shapes, terminus profile angles, terminus profile slopes, or even asymmetry along an alternate axis may be created using the concept of the present invention, all without departing from the scope and content of the present invention. In fact, the present invention could even be applicable to scorelines that are completely symmetrical and still fall within the purviews of the present invention if it is formed using the methodologies described in FIG. 5 above, also without departing from the scope and content of the present invention.
Other than in the operating example, or unless otherwise expressly specified, all of the numerical ranges, amounts, values and percentages such as those for amounts of materials, moment of inertias, center of gravity locations, loft, draft angles, various performance ratios, and others in the aforementioned portions of the specification may be read as if prefaced by the word “about” even though the term “about” may not expressly appear in the value, amount, or range. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the preceding specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting form the standard deviation found in their respective testing measurements. Furthermore, when numerical ranges of varying scope are set forth herein, it is contemplated that any combination of these values inclusive of the recited values may be used.
It should be understood, of course, that the foregoing relates to exemplary embodiments of the present invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.

Claims

1. A method of forging a golf club head comprising:

providing a raw forging blank,

hot pre-forging said raw forging blank to create a golf club head without scorelines,

cold pre-forging said golf club head to create a rough scoreline pattern,

polishing a face of said golf club head to remove an excess material after said cold pre-forging step, and

final forging said golf club head to create a final scoreline pattern,

wherein an at least one scoreline of said final scoreline pattern further comprises;

a toe terminus profile,

a heel terminus profile, and

a face centerline, defined as a center point between the toe most portion of said at least one scoreline and a heel most point of said at least one scoreline, and

wherein said toe terminus profile is different from said heel terminus profile.

2. The method of claim 1, further comprising a step of flattening said face of said golf club head before said step of final forging said golf club head.

3. The method of claim 2, wherein said step of flattening said face occurs after said step of hot pre-forging.

4. The method of claim 2, wherein said step of flattening said face occurs after said step of cold pre-forging.

5. The method of claim 2, wherein said step of flattening said face occurs after said step of polishing said face.

6. The method of claim 1, wherein said scoreline has Heel to Toe Terminus Slope Ratio of greater than about 6, said Heel to Toe Terminus Slope Ratio defined as;

Heel to Toe Terminus Slope Ratio = \frac{Heel Terminus Profile Slope}{Toe Terminus Profile Slope} .

7. The method of claim 1, wherein a slope of said toe terminus profile is less than a slope of said heel terminus profile.

8. A method of forging a golf club head comprising:

providing a raw forging blank,

cold pre-forging said golf club head to create a rough scoreline pattern,

final forging said golf club head to create a final scoreline pattern,

a toe terminus profile,

a heel terminus profile, and

wherein said toe terminus profile is different from said heel terminus profile, and

wherein at least one of said toe terminus profile or said heel terminus profile is chamfered, and wherein the other one of said toe terminus profile or said heel terminus profile is radiused.

9. The method of claim 8, said at least one scoreline is asymmetrical about said face centerline.

10. The method of claim 8, wherein said at least one scoreline has Heel to Toe Terminus Slope Ratio of greater than about 6, said Heel to Toe Terminus Slope Ratio defined as;

Heel to Toe Terminus Slope Ratio = \frac{Heel Terminus Profile Slope}{Toe Terminus Profile Slope} .

11. The method of claim 10, wherein said Heel to Toe Terminus Slope Ratio is greater than about 8.75.

12. The method of claim 11, wherein said Heel to Toe Terminus Slope Ratio is greater than about 13.

13. The method of claim 8, wherein said toe terminus profile has a slope of less than about 0.25.

14. The method of claim 13, wherein said toe terminus profile has a slope of less than about 0.20.

15. The method of claim 14, wherein said toe terminus profile has a slope of less than about 0.15.

16. The method of claim 13, wherein said heel terminus profile has a slope of greater than about 1.50.

17. The method of claim 16, wherein said heel terminus profile has a slope of greater than about 1.75.

18. The method of claim 17, wherein said heel terminus profile has a slope of greater than about 2.0