GOLF CLUB HEAD WITH FACE CHANNEL

Abstract

The present invention generally relates to golf club heads with improved mass distribution provided by novel structural features. The golf club head can include a main club head body and a face member that presents a ball striking face. The face member of the club head has at least one channel located thereon.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 61/846,121, filed Jul. 15, 2013, the contents of which are incorporated by reference.

FIELD OF THE INVENTION

The present invention generally relates to golf club heads, and more specifically, golf club heads having a channel running through the face portion of the club head.

BACKGROUND

When golfers make a shot, they typically want the ball to travel a certain distance in a certain direction. Most golfers realize that in order to achieve this goal, it is often best to contact the ball at or near the center of club face, i.e., in the sweet spot. This can be easier said than done and many golfers have yet to develop the skill to consistently make high-power shots in which the golf ball is struck right with the sweet spot of the face. Furthermore, golfers get frustrated when they see that many of their shots do not to travel far enough.

SUMMARY

The present invention provides a golf club head in which the face includes a face channel to improve mass distribution properties of the club head and increase a coefficient of restitution of the face. Relative to a similar club head without the face channel, a club head of the invention can have a higher moment of inertia (MOI), lower or more rearward center of gravity (CG), or both. Additionally, where the face channel is on an exposed surface of the club head, the face channel provides a boundary layer tripping mechanism that delays airflow separation and reduces drag, thus improving global air separation. Since removing mass via a face channel allows that mass to be placed further towards the heel or toe of the club head, improving MOI, the club head is more forgiving to off-center hits. Also, the face channel improves face resilience and increases the trampoline effect thus positively affecting coefficient of restitution. Since coefficient of restitution is increased, the golf club is given a “hot face” or a larger sweet spot. Particularly in combination with the possible improvements in aerodynamics that a channel can provide, a club head of the invention can swing very fast and impart great energy to the ball.

Since a club head with a face channel is more forgiving to off-center hits and can also impart great energy to the golf ball, a golfer can be provided with a golf club that hits the ball a great distance in the intended direction.

In certain aspects, the invention provides a golf club head having a club-head body comprising a heel portion, a toe portion, a top portion, and a sole portion. A hosel extends upwards from the heel portion when the club head is at address and the club head further includes a ball-striking face member at the front of the body and at least one channel on the ball-striking face member. The face channel provides an aerodynamic boundary layer tripping mechanism delaying airflow separation and reducing drag, thus affecting global air separation. The face channel may increase a trampoline effect and increasing resiliency. The face channel may be on either side (ball striking face or the obverse) of the face member. The face channel may be partially filled or completely filled (e.g., with a non-metallic material) to fine-tune aerodynamics or sound. In some embodiments, the face channel is partially filled (e.g., with TPU). Having a channel filled may improve aerodynamic and inertial properties. Sound may be improved.

The channel preferably defines a groove or indentation that runs along the surface of the face. As already noted, this indentation can run on the interior surface of the face, the exterior surface of the face, or both the exterior and interior surface. As encompassed by the invention, the channel can be one contiguous indentation or a plurality of indentations that together delineate a channel.

The provided channels can include other configurations besides grooves. For example, channels of the invention can also encompass substantially enclosed tubular structures. The channels may also be partially enclosed as well.

Channels of the invention can include continuous channels. In this aspect, the channel forms a closed loop that runs along the surface of the face. In other aspects, however, the channel is discontinuous and does not form a closed loop. For example, the ends of the channel could meet at the hosel of the golf club.

As noted above, the orientation of the channel redistributes the mass of the face in a way that optimizes the MOI and CG of the club head. In certain aspects, the channel is orientated such that it runs substantially along the perimeter of the face. This redistributes the mass towards the center of the club, thereby increasing the center of gravity at this location. Because the channel is located primary at the edges of face, there is less surface in this area to hit the ball in an off-center manner. In addition, because the channel in certain aspects is substantially at the face perimeter but not at the face perimeter, there is still a small band of non-channel surface at the face perimeter to the outside of the channel. This configuration concentrates mass towards the outermost edge, where it is believed to increase the MOI of the club head.

The described features of the invention provide a number of benefits for the golfer frustrated with conventional golf clubs. Because the club head of the invention has a high MOI, it does not twist in space during off-center contact with the ball. As a result, even an off-center shot can still send the ball in the intended direction. In addition, because the provided club head has a very low center of gravity, it imparts high momentum and more loft to the golf ball, causing the ball to travel the intended distance. With these benefits, golfers using the provided golf club head will make their intended shots with greater consistency.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a golf club head from a three-quarters perspective.

FIG. 2 illustrates a golf club from a front perspective.

FIG. 3 shows a golf club head from a toe side.

FIG. 4 shows a golf club head from a heel side.

FIG. 5 illustrates a club head from above.

FIG. 6 gives a perspective view of a club head according to certain embodiments.

FIG. 7 shows a face of a club head.

FIG. 8 shows a wood-type club head from a toe side.

FIG. 9 shows a club head from above.

FIG. 10 shows a face of an iron-type club head.

FIG. 11 give a perspective view of a face.

FIG. 12 shows a back of a cavity-back iron.

FIG. 13 gives a perspective view of a club head.

FIG. 14 shows a club head with face insert.

FIG. 15 shows a face insert for a club head.

FIG. 16 gives a cross-section through a club head.

FIG. 17 shows a 9 iron with a channel on a back of a strike face.

FIG. 18 shows a 7 iron with a channel on a back of a strike face.

FIG. 19 gives a cross-section through a club head face analyzed for regions of stress.

DETAILED DESCRIPTION

The present invention generally relates to golf club heads with improved mass distribution provided by novel structural features. The golf club head can include a body and a face connected to the body. The face of the club head has at least one channel located thereon. While the embodiments disclosed herein include driver-type club heads, it is contemplated that the concepts described herein are applicable to other types of club heads, such as hybrids, irons, and putters.

Generally speaking, the club head is the part of the golf club attached to the end of the shaft. Club head describes the whole of the head, as opposed to the club face, which describes only the forward-facing, outer surface of the club head designed for striking the ball. The club head can be blade-like, as in a traditional iron, or larger and rounded, as in a metal wood club head, or many variations in-between. The design of the club head affects characteristics such as center of gravity and moment of inertia, factors that influence how the golf ball flies after impact.

Moment of inertia or MOI, is a property of physics that indicates the relative difference in how easy or difficult it will be to set any object in motion about a defined axis of rotation. The higher the MOI of an object, the more force will have to be applied to set that object in a rotational motion. Conversely, the lower the MOI, the less force needed to make the object rotate about an axis.

There are several different moments of inertia that factor in the performance of a golf club. Accordingly, MOI is first defined by identifying which axis the object is rotating around. For example, there is an MOI for the whole golf club which is rotated around the golfer during the swing.

There are also three different MOIs that pertain to the club head itself. Two of these MOIs are important in the design of any club head. First, when a shot is hit off the center of the face, even though the head is secured to a shaft, the head will try to rotate around the vertical axis going through the club head's center of gravity. Second, and at the same time, when the golfer swings the club on the downswing, the club head is rotating around the axis through the center of the shaft.

The first example refers to the MOI of the club head about its center of gravity. The larger the club head, and/or the more the club head design incorporates perimeter weighting, the higher the MOI of the club head about its center of gravity vertical axis will be. The higher the MOI of the head about its vertical CG axis, the less the head will twist in response to an off-center hit, and the less distance will be lost from that off-center hit. Accordingly, a high MOI in this instance is desirable.

The smaller the head and the more head weight is positioned close to the center of the head, the lower the MOI of the head will be around its vertical CG axis, and the more distance will be lost when the ball is hit off center.

Again, higher MOI equals more resistance to the object being rotated around an axis; lower MOI equals less resistance to the object rotating around an axis.

The second example refers to the MOI of the club head about the shaft axis. The bigger the head or the more weight that is placed far out on the toe of the club head, the higher the MOI of the head will be about the shaft's axis. The smaller the head or the more weight that is positioned in the heel area of the head, the lower the MOI of the head will be about the shaft's axis. The higher the club head MOI around the shaft, the more tendency there is for a golfer to leave the face open at impact. The lower the club head MOI around the shaft, the more tendency there is for a golfer to rotate the face more closed at impact. Once again, it is more desirable to have a high MOI than a low one.

The center of gravity (CG) of an object refers the intersection of all the possible balance points of that object. In a golf club head, the CG can be determined by balancing the head on its face, sole, or any place on the head; the intersection inside of the head of all these different balance points is the center of gravity of the club head.

Because the center of gravity is a single point inside the club head, its location has to be defined in 3-dimensions. This means that a club head has a vertical CG location (how high up in the head the CG is from the sole when the club head is at address). It also has a horizontal CG location (how far over it is from the center of the shaft in the hosel of the head). Finally, the center of gravity is also defined by how far back from the clubface it is located.

The lower the center of gravity and the farther back the center of gravity is from the face of the club, the higher the trajectory of the shot will be for any given loft angle on the club head. Accordingly, a lower center of gravity is more desirable than a higher center of gravity. Of the two CG locations that affect the height of the shot, the CG back from the face has a greater effect on the height of the shot than does the vertical CG (up from the sole).

The horizontal center of gravity location, or how far the CG is over from the center of the shaft, is a design factor that affects the accuracy of the shot. The closer the CG is to the shaft, the less tendency there will be for the golfer to push or fade the ball offline. And the farther the center of gravity is from the shaft, the more tendency there will be for the golfer to push or fade the ball offline.

The reason is that the closer the center of gravity is to the shaft, the lower the moment of inertia about the shaft axis will be, and the greater the tendency will be for the golfer to rotate the face of the club less open by the time the head gets to impact with the ball. The farther the CG from the shaft, the higher the MOI will be about the shaft axis, and the greater the tendency for the golfer to leave the face of the club open by the time the head gets to impact with the ball.

The invention provides golf club heads with improved physical properties, including MOI and CG. In particular, the invention provides a club head with a face channel that results in these improved characteristics. The channel removes weight from the front of the club head and in doing so, redistributes weight towards the rear. As previously mentioned, the further back the center of gravity is from the face of the club, the higher the trajectory of the shot will be for any given loft angle on the club head. In addition, the provided channel redistributes the mass around the perimeter of the face. Without being constrained to theory, it is believed that the manner in which the provided face channel redistributes mass, the MOI is increased in a desirable fashion. To facilitate discussion of the invention, reference will now be made to the provided figures.

FIG. 1 shows a golf club head 101 from a three-quarters perspective. Club head 101 is, in some embodiments, constructed as a hollow, wood-type golf club head and includes a club head body 102 defining a heel portion, a toe portion, a top portion, and a sole portion. Club head 101 includes a hosel 10 extending upwards from the heel portion of body 102. Club head 101 includes ball-striking face member 103 at the front of body 102, as well as at least one channel 104 located on the face member 103.

FIG. 2 illustrates a golf club 101 from the front with a channel 104 around strike face 103. The provided channels are not the same as score lines that are typically featured on the face of golf club heads. Score lines consist of markings, usually horizontal and linear, etched into the face of a golf club to enhance spin direction and decrease hydroplaning. Golf club heads having score lines can be found in U.S. Pat. No. 7,285,057 and in U.S. Pub. 2013/0109498, each of which is incorporated herein by reference. In certain embodiments, however, the face of the club head can include both a channel and a plurality of score lines. In the preferred embodiments, the channel runs substantially along or parallel to the perimeter of the face. Accordingly, in these embodiments, the score lines would be substantially contained within the outline of the channel, on the exterior surface of the face.

FIG. 3 shows a golf club head from a toe side. Face member 103 is disposed on the perimeter body and provides a front ball striking surface. Face member 103 may have an overall equivalent thickness, e.g., between about 1.5 mm and about 4.0 mm. Additionally, face member 103 may be formed integral with perimeter body or as a separate component that is coupled to the perimeter body. Face member 103 may be constructed from the same or a different material than the perimeter body and hosel 10, and it combines with the perimeter body to define a rear cavity.

FIG. 4 shows hosel 10 on club head 101. Hosel 10 is disposed on a heel end of face 14 and the perimeter body, and provides an attachment to a shaft so that club head 101 may be assembled into a complete golf club. Hosel 10 may be constructed integral with face member 103 and body 102. Hosel 10 may also be constructed from the same, or a different, material than face 14 and/or the perimeter body.

FIG. 5 shows club head 101 from above. Golf club heads of the invention include a face channel 104. As depicted, the channel 104 can be a groove or indentation that runs along the surface of the face. The mass of a club head with the face channel is less than the mass of the club head without the channel. In addition, the provided club head has a face mass that is distributed towards the perimeter of the face. As explained in detail below, this distribution of mass due to the channel optimizes certain characteristics of the club head, including MOI and CG.

In preferred embodiments, the channel is curved or non-linear in at least some portion of channel. In the embodiment shown, the channel 104 runs along the exterior side of the face 103 (i.e., the side contacting the ball). In certain embodiments, the channel is located solely on the exterior surface of the face. In other words, any channels are located only on the exterior face surface without any channels or grooves located on the interior face surface. In some embodiments, this may mean that the interior surface of the face is substantially smooth and free of any channels located on the interior surface. An unexpected benefit of having the channels limited to only one surface of the face, such as the exterior surface, is that the club head is easier to manufacture. In other embodiments, however, the channel can run along the interior side of the face. In further embodiments, the channel can run along both the exterior and interior surfaces of the club face.

The depth of the channel can vary as needed. In certain aspects, the depth of the channel may exceed the width of the face. In this instance, the channel when located on the exterior face surface may have a corresponding protruding surface (e.g. a “rail”) on the interior surface of the face. In other aspects, the depth of the channel is less than the width of the face and there is no corresponding protruding surface.

In the embodiment shown, the channel 104 can be contiguous, with no apparent breaks in the channel. In other embodiments, however, the channel can comprise a plurality of indentations that when taken together, delineate a channel. For example, the channel can comprise a plurality of dots or other shapes impressed into the surface of the face that taken together, form a channel.

Channels of the invention do not necessarily need to comprise a groove or indentation. For example, the provided channel can be a tubular structure running along club face. With a tubular structure, the provided channel can be substantially enclosed around its circumference or less than substantially enclosed around its circumference.

As shown in FIGS. 1-5, channel 104 may be discontinuous and with multiple ends. As shown, the ends of the channel 104 terminate at the hosel 10.

FIG. 6 shows a club head 101 in which a channel 104 forms a continuous loop with no start or end terminals.

FIG. 7 gives a front view of a continuous loop face channel. In this instance, the channel 104 and the hosel 10 may define a border surrounding a portion of the face 103. Having the channel form a continuous loop or discontinuous loop is believed to impart different qualities (e.g., MOI and CG) to the club. In other words, although golf club heads of the invention are believed to have better MOI and CG than conventional club heads, it is also believed that the MOI and CG of the provided continuous and discontinuous club heads will not necessarily be the same.

FIG. 8 shows a wood-type club head from a toe side.

FIG. 9 shows a club head 101 from above, showing continuous loop channel 104 on the face of the club head.

There can also be more than one channel on the face panel. For example, the club head may feature two, three, or more channels. In certain embodiments, the plurality of channels may be positioned concentrically. While the foregoing description has accompanied figures generally depicting a hollow, wood-type golf club head, face channel 104 may be provided on a ball-striking face member 103 on any suitable club head type such as, for example, an iron, a wedge, a hybrid, a putter, or others.

FIG. 10 shows an iron-type golf club head 1001 having a club-head body comprising a heel portion, a toe portion, a top portion, and a sole portion. A hosel extends upwards from the heel portion when the club head is at address and the club head further includes a ball-striking face member 103 at the front of the body and at least one channel 104 on the ball-striking face member. Specifically, club head 1001 is depicting with ball striking face 103 having channel 104 extending across a top portion of it. Channel 104 may extend across part or all of a top, bottom, heel side, or toe side, or any combination thereof of face member 103.

FIG. 11 give a front view of an iron-type club head 1101 with a continuous loop channel 104 on the face thereof. Embodiments depicted herein show a face channel on a forward surface of face member 103. Face channel 104 may additionally or alternatively be an obverse surface of member 103 (e.g., on the inside of a hollow club head or on the back of an iron).

FIG. 12 shows a back of a cavity-back iron club head 1201 having a channel 104 extending across a back of the ball-striking face. It may be preferable to include channel 104 on a back surface of face member 103, particularly on irons or other short-distance clubs, as aerodynamic considerations may decrease relative to spin and other dynamics in comparison to woods.

FIG. 13 gives a back view of a cavity-back iron-type club head 1301 having a discontinuous, multi-piece channel 104 disposed across only a portion (here, heel-side) of the top of the back of the ball-striking face. Use of a discontinuous (e.g., multi-segment) channel provides for very fine control over fine-tuning mass distribution when designing a club head.

FIG. 14 illustrates an iron-type club head 1401 with a face insert piece 1403 to be assembled to make the finished club head. A face insert construction as depicted here may be preferable from a manufacturing perspective as it uncoupled the club head from the channel 104. That is, a number of club head bodies can be made via a single process, and then different face inserts with different channel patterns can be coupled to the club head bodies. Thus two golfers can have the same club type (for example, the same brand and model of 7 iron) but one golfer can have a face channel that corrects for a hook, the other for a slice. The depicted construction provides a ready mechanism by which a club head manufacturer can customize the face channel pattern for customers.

FIG. 15 shows a back side of face member 1403 having a channel 104 disposed around a top portion of the back surface. As depicted, channel 104 extends across a top area of the face member and down along a portion of each of the heel side and the toe side of the face member. (Channel 104 is depicted as being on the obverse of the ball-striking side of face member 1403; additionally or alternatively the ball-striking side could include a channel.) The depicted geometry lowers a CG of club head 1403 by allowing additional mass (mass that is “saved” by including the face channel) to be moved to a sole area of the club head.

FIG. 16 gives a cross-section through club head 1401 to illustrate the relief provided by channel 104. As shown in FIG. 16, channel 104 has a substantially semi-circular cross section. Channel 104 may have any suitable cross section include U-shaped, square-shaped, V-shaped, W-shaped (i.e., multi-grooved), WW-shaped, etc.

FIG. 17 shows a 9 iron with a channel on a back of a strike face. The illustrated embodiment provides a club head that is forgiving to off-center hits and in which the face has a high coefficient of restitution.

FIG. 18 shows a 7 iron with a channel on a back of a strike face.

FIG. 19 gives a cross-section through a club head face analyzed for regions of stress. As shown in FIG. 19, portions of the club head at the crown, at the sole, and in the center of the face have been determined to be high tension stress zones. The invention includes the insight that it may be beneficial to leave those areas thick for maximum stress. A stress transition zone extends around the face generally between the high tension stress zones and the invention further includes the insight that a stress transition zone is a suitable place to include a face channel for weight savings or other benefits as discussed herein. The region of relatively low stress comprises a relatively low tensile stress level on both an internal wall and external wall of the face. Preferably, channel is 104 positioned along a region of relatively low stress on the face.

Although the channel can be located anywhere along the club face, in certain aspects of the invention, the channel runs along or parallel to the perimeter of the club face or substantially along or parallel to the perimeter. As shown herein, when the channel 104 runs substantially along or parallel to the perimeter, there is still some of the face surface beyond the channel 104. In this configuration, the provided channel redistributes the mass of the face in a manner known as perimeter weighting.

Perimeter weighting refers to the removal of mass from the center of the club head (or other location) repositioning that weight around the club head's perimeter. Perimeter-weighted clubs are believed to be more “forgiving” than non-perimeter weighted clubs. This means that an off-center shot made with a perimeter-weighted club head is less likely to result in the ball travelling in an unintended direction.

The more head weight is pushed out farther from the center of gravity of the club head, the higher the club head's MOI about the vertical rotation axis of its center of gravity. The higher the club head's MOI, the less the head will twist in response to an off-center hit. And the less head twisting from an off-center hit, the farther the ball will fly for the same golfer swing speed. Perimeter weighting works by increasing a club's MOI, thereby leading to less loss of distance on off-center hits.

Accordingly, the provided face channels redistribute the weight of the club face to the face perimeter. This results in a number of benefits for the golfer with a less than accurate shot. Because the club head of the invention has a high MOI, it does not twist in space during off-center contact with the ball. As a result, even an off-center shot can still send the ball in the intended direction.

Other factors have also helped determine the position of the provided face channels. As such, the placement of the face channel along the perimeter, substantially along the perimeter, or parallel to the perimeter of the face is not an arbitrary choice. Rather, the position of channel considers a number of factors that affect the club performance and durability. Performance factors have already been described at length above. A primary concern in metal wood club head durability is the mitigation of crack propagation. In other words, it is particularly desirable to construct a club head that does not easily allow cracks to propagate.

In metal woods, cracks tend to propagate from high tensile stress regions, such as on the back of the face, the leading edge on the sole, and on the front of the crown.

FIG. 19 illustrates those high tension stress zones. One way to mitigate crack propagation in these areas is to increase wall thickness. However, in regions where tensile stresses are relatively low, the thickness of the face can be reduced in an effort to increase the discretionary weight of the club head.

In order to reduce the wall thickness of a part in a specific area, that area must experience low tensile stress levels on both internal and external walls of the face. It has been found that, for metal woods, there are stress transition areas around the face that experience low tensile stress levels on both the internal and external face walls. Therefore, the wall thicknesses in these regions can be reduced without affecting the overall durability of the club head. It is along these stress transition regions that the channel of the invention would be positioned. The stress transition areas are also depicted in FIG. 19.

Other than in the operating examples, or unless otherwise expressly specified, all of the numerical ranges, amounts, values and percentages such as those for amounts of materials, moments of inertias, center of gravity locations, loft and draft angles, and others referenced herein may be read as if prefaced by the word “about” even though the term “about” may not expressly appear with the value, amount, or range. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following 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 from 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.

Incorporation by Reference

References and citations to other documents, such as patents, patent applications, patent publications, journals, books, papers, web contents, have been made throughout this disclosure. All such documents are hereby incorporated herein by reference in their entirety for all purposes.

Equivalents

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing embodiments are therefore to be considered in all respects illustrative rather than limiting on the invention described herein. Scope of the invention is thus indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. A golf club head comprising:

a club-head body comprising a heel portion, a toe portion, a top portion, and a sole portion

a hosel extending upwards from the heel portion when the club head is at address;

a ball-striking face member at the front of the body; and

at least one channel on the ball-striking face member.

2. The golf club head of claim 1, wherein the channel includes a curve.

3. The golf club head of claim 1, wherein any portion of the channel is non-linear.

4. The golf club head of claim 1, wherein the channel runs parallel to a perimeter of the face.

5. The golf club head of claim 1, wherein the channel is located on an exterior surface of the face.

6. The golf club head of claim 5, wherein the channel is located solely on the exterior surface of the face.

7. The golf club head of claim 1, wherein the face has an interior surface that is substantially smooth.

8. The golf club head of claim 1, wherein the face has an interior surface that is free of any channels located thereon.

9. The golf club head of claim 5, wherein the channel has a corresponding protruding surface on an interior surface of the face.

10. The golf club head of claim 1, wherein the channel is a discontinuous channel.

11. The golf club head of claim 10, wherein the discontinuous channel has at least two ends.

12. The golf club head of claim 11, wherein the body comprises a hosel and the ends of the channel terminate at the hosel.

13. The golf club head of claim 1, wherein the channel comprises an indentation along a surface.

14. The golf club head of claim 1, wherein the channel is substantially enclosed.

15. The golf club head of claim 1, wherein the channel is partially enclosed.

16. The golf club head of claim 1, wherein the channel comprises a plurality of indentations.

17. The golf club head of claim 1, wherein the channel and the hosel define a border surrounding a portion of the face.

18. The golf club head of claim 1, further comprising at least a second channel.

19. The golf club head of claim 18, wherein the second channel extends around the channel.

20. The golf club head of claim 1, wherein the face further comprises a plurality of score lines located thereon.

21. The golf club head of claim 1, wherein the channel is positioned along a region of relatively low stress on the face.

22. The golf club head of claim 21, wherein the region of relatively low stress comprises a relatively low tensile stress level on both an internal wall and external wall of the face.

23. The golf club head of claim 1, wherein the channel is located within a back cavity of the club head body.

24. The golf club head of claim 1, wherein the channel is continuous and has a shape that mimics a shape of a ball-striking face on the ball-striking face member.