Golf club head with improved striking face

Abstract

To provide a golf club head with an improved striking face.SOLUTION: In a golf club head, a striking face further consists of: a thickened central region located near a geometric center of a striking face portion 1902; a central transition region extending radially outward from the thickened central region; a thinned intermediate region extending radially outward from the central transition region; a thickened stress reducing region extending radially outward from the thinned intermediate region; and a thinned perimeter region extending outward radially from the thickened stress reducing region; all of which combine to form the improved striking face.SELECTED DRAWING: Figure 19

Description

[Technical field]

[0001] The present invention relates generally to golf club heads having improved striking faces, and more particularly to metal wood type golf club heads having a striking face having a thickened central region located near a geometric center of the striking face portion, a central transition region extending radially outward from the thickened central region, a thinner intermediate region extending radially outward from the central transition region, a thickened stress reduction region extending radially outward from the thinner intermediate region, and a thinner peripheral region extending radially outward from the thickened stress reduction region, which combine to form an improved striking face. [Background technology]

[0002] The striking face of a golf club head is the single component of the golf club head that is subjected to the highest levels of stress when striking a golf ball, and since it is the only component that comes into contact with the golf ball, it is one of the most critical components in the design of any golf club.

[0003] To improve the performance of golf club heads through the striking face, golf club designers have attempted to create a striking face that is very thin, which allows the striking face to elastically deform upon impact with a golf ball, thereby increasing the speed of the golf ball after it leaves the striking face of the golf club head, while still adhering to the rules of golf. U.S. Patent No. 4,432,549 to Zebelean shows one of the early attempts to thin the striking face of a golf club head by thinning the upper portion of the striking face of the golf club head.

[0004] Thinning the face is not the only way to improve the performance of a golf club head's striking face, and more recent improvements include adjusting the thickness of various parts of the striking face to improve performance. Based on an already thin face, U.S. Patent No. 6,863,626 to Evans et al. illustrates one of the early attempts to vary the thickness of a golf club head's striking face, which discloses that a thicker central region decreases from the center outward to help reduce the speed of the golf ball at the center, creating a large area of ​​improved speed and performance.

[0005] Further building on the known art of a thin face combined with a thick central portion, to further improve the performance of golf club heads, U.S. Patent No. 10,758,789 to Bacon et al. adds a thicker peripheral region to the ends of the striking face, which the inventors claim improves durability, increases ball speed, and increases characteristic time. However, while this addition is beneficial, it is not optimal because, as shown in U.S. Patent No. 10,758,789, the benefits of the thicker peripheral region are generally localized and do not need to extend all the way to the periphery of the striking face.

[0006] Thus, it can be seen that for golf club heads having a thin face, a thick central region, and also having thicker peripheral regions, further improvements can be made by removing unnecessary weight from the peripheral edges of the striking face and localizing the thickened peripheral regions only in optimized locations that can benefit from such features. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] U.S. Patent No. 4,432,549 [Patent Document 2] U.S. Patent No. 6,863,626 [Patent Document 3] U.S. Patent No. 10,758,789 Summary of the Invention

[0008] One aspect of the invention is a golf club head having a striking face portion positioned at a front portion of the golf club head and adapted to strike a golf ball, and a body portion attached rearwardly of the striking face portion, the striking face portion further having a substantially planar front striking surface and an inner rear surface, the front striking surface and the inner rear surface in combination further comprising a thickened central region positioned near a geometric center of the striking face portion and having a first thickness, and a thickened central region extending from the thickened central region by a semi-thick portion. the golf club head having a central transition region extending radially outwardly and having a variable thickness, a thinned intermediate region extending radially outwardly from the central transition region and having a third thickness, a thickened stress reduction region extending radially outwardly from the thinned intermediate region and having a fourth thickness, and a thinned peripheral region extending radially outwardly from the thickened stress reduction region and having a fifth thickness, the thickened stress reduction region forming a ring projecting rearwardly from the inner rear surface of the striking face portion, the fourth thickness being greater than the first thickness.

[0009] Another aspect of the invention is a golf club head having a striking face portion positioned at a front portion of the golf club head and adapted to strike a golf ball, and a body portion attached rearwardly of the striking face portion, the striking face portion further having a substantially planar front striking surface and an inner rear surface, the front striking surface and the inner rear surface in combination further comprising a thickened central region positioned near a geometric center of the striking face portion and having a first thickness, and a middle portion extending radially outwardly from the thickened central region and having a variable thickness. the golf club head having a central transition region, a thinned intermediate region extending radially outward from the central transition region and having a third thickness, a thickened stress reduction region extending radially outward from the thinned intermediate region and having a fourth thickness, and a thinned peripheral region extending radially outward from the thickened stress reduction region and having a fifth thickness, the thickened stress reduction region forming a ring projecting rearwardly from the inner rear surface of the striking face portion, the fifth thickness being less than the fourth thickness, and the third thickness of the thinned intermediate region being the thinnest portion of the striking face portion.

[0010] Another aspect of the invention is a golf club head having a striking face portion positioned at a front portion of the golf club head and adapted to strike a golf ball, and a body portion attached rearwardly of the striking face portion, the striking face portion further having a substantially planar front striking surface and an inner rear surface, the front striking surface and the inner rear surface in combination further having a thickened stress reduced region positioned about the periphery of the striking face portion, the thickened stress reduced region forming a ring projecting rearwardly from the inner rear surface of the striking face portion, the thickened stress reduced region being located a distance between about 15 mm and about 30 mm from the geometric center of the striking face portion as measured across a vertical cross section passing through the geometric center of the striking face portion.

[0011] In another aspect of the invention, the thickened stress reduced region forms at least a portion of a ring that projects rearwardly from the inner rear surface of the striking face portion.

[0012] In another aspect of the invention, the inner rear surface may be divided into a clock grid having at least a 12 o'clock ray mark (also called a ray, index or hour mark), a 1 o'clock ray mark, a 2 o'clock ray mark, a 3 o'clock ray mark, a 4 o'clock ray mark, a 5 o'clock ray mark, a 6 o'clock ray mark, a 7 o'clock ray mark, an 8 o'clock ray mark, a 9 o'clock ray mark, a 10 o'clock ray mark, and an 11 o'clock ray mark, and the thickened stress reduction regions are located only in the area consisting of an upper region between the 9 o'clock ray mark and the 2 o'clock ray mark and a lower region between the 9 o'clock ray mark and the 3 o'clock ray mark.

[0013] In another aspect of the invention, the thickness stress reduced region comprises a region of reduced thickness between the 8 o'clock light mark and the 10 o'clock light mark to form a stress reduced region of increased heel thickness.

[0014] In another aspect of the invention, the thickened stress reduced region forms a horseshoe shaped ring.

[0015] In another aspect of the invention, a golf club head further having a striking face portion located at a front portion of the golf club head and configured to strike a golf ball, and a body portion attached rearwardly of the striking face portion, the striking face portion further having a peripheral region having a central opening, the peripheral region further having a thickened stress reduction region having a fourth thickness and a face insert adapted to engage the central opening, the face insert further having a thickened central region located near a geometric center of the striking face portion and having a first thickness, no portion of the thickened stress reduction region engages the face insert, and the fourth thickness is greater than the first thickness.

[0016] In another aspect of the invention, the top shelf of the central opening is located less than about 1.0 mm from the crown tip of the striking face portion.

[0017] In another aspect of the invention, the aspect ratio of the face insert is from about 1.3 to about 1.7.

[0018] In another aspect of the invention, the top shelf of the central opening is located less than about 10 mm from the crown apex.

[0019] These and other features, aspects, and advantages of the present invention will become better understood with reference to the following drawings, description, and claims. [Brief description of the drawings]

[0020] The foregoing and other features and advantages of the present invention will become apparent from the following description of the invention as illustrated in the accompanying drawings, which are incorporated herein and form a part of the specification, and further serve to explain the principles of the invention and enable one skilled in the relevant art to make and use the invention. [Figure 1] FIG. 1 of the accompanying drawings shows a front view of a golf club head in accordance with an exemplary embodiment of the present invention, showing section line A-A'. [Diagram 2] FIG. 2 of the accompanying drawings shows a cross-sectional view of a golf club head in accordance with an exemplary embodiment of the present invention taken along section line A-A' shown in FIG. [Diagram 3] FIG. 3 of the accompanying drawings illustrates an enlarged cross-sectional view of the striking face portion of the golf club head in accordance with the exemplary embodiment of the present invention shown in FIG. [Figure 4] FIG. 4 of the accompanying drawings again shows an enlarged cross-sectional view of the striking face portion of the golf club head in accordance with the exemplary embodiment of the present invention shown in FIG. 2, highlighting various features. [Diagram 5] FIG. 5 of the accompanying drawings again shows an enlarged cross-sectional view of the striking face of the golf club head in accordance with the exemplary embodiment of the present invention shown in FIG. 2, highlighting various features. [Figure 6] 6a-6l show representative cross-sectional views of thickened stress reduced regions in accordance with exemplary embodiments of the present invention. [Figure 7a] FIG. 7a of the accompanying drawings illustrates a shaded rear view of a striking face portion of a golf club head in accordance with an exemplary embodiment of the present invention. [Figure 7b] FIG. 7b of the accompanying drawings illustrates a rear view of the striking face portion of a golf club head in accordance with an exemplary embodiment of the present invention. [Figure 8] FIG. 8 of the accompanying drawings shows a cross-sectional view of a golf club head in accordance with yet another embodiment of the present invention taken along section line A-A' shown in FIG. [Figure 9] FIG. 9 of the accompanying drawings illustrates an enlarged cross-sectional view of the striking face portion of the golf club head in accordance with the alternative embodiment of the present invention shown in FIG. [Figure 10a] Accompanying drawing 10a shows a shaded rear view of the striking face of a golf club head in accordance with another embodiment of the present invention. [Figure 10b] FIG. 10b of the accompanying drawings illustrates a rear view of a striking face portion of a golf club head in accordance with another embodiment of the present invention. [Figure 11] FIG. 11 of the accompanying drawings illustrates an exploded view of a golf club head in accordance with yet another alternative embodiment of the present invention. [Figure 12] FIG. 12 of the accompanying drawings illustrates a cross-sectional view of a golf club head in accordance with yet another alternative embodiment of the present invention. [Figure 13] FIG. 13 of the accompanying drawings illustrates a partial cross-sectional view of a striking face portion of a golf club head in accordance with yet another alternative embodiment of the present invention. [Figure 14] FIG. 14 illustrates a rear view of a striking face portion of a golf club head according to yet another embodiment of the present invention. [Figure 15] FIG. 15 illustrates a rear view of a striking face portion of a golf club head according to yet another embodiment of the present invention. [Figure 16] FIG. 16 of the accompanying drawings illustrates an enlarged cross-sectional view of a striking face portion in accordance with an alternative embodiment of the present invention. [Figure 17]FIG. 17 of the accompanying drawings illustrates a rear view of a striking face portion of a golf club head in accordance with yet another alternative embodiment of the present invention. [Figure 18] FIG. 18 of the accompanying drawings illustrates an enlarged cross-sectional view of a striking face portion of a golf club head in accordance with yet another alternative embodiment of the present invention. [Figure 19] FIG. 19 of the accompanying drawings illustrates a rear view of a striking face portion of a golf club head in accordance with yet another embodiment of the present invention. [Figure 20] FIG. 20 of the accompanying drawings illustrates a rear view of the striking face portion of a golf club head with the face insert removed in accordance with yet another embodiment of the present invention. [Figure 21] FIG. 21 of the accompanying drawings illustrates an enlarged rear view of a face insert in accordance with yet another embodiment of the present invention. [Figure 22] FIG. 22 of the accompanying drawings is an enlarged cross-sectional view of a striking face portion in accordance with yet another embodiment of the present invention taken along section line 22-22' of FIG. [Figure 23] FIG. 23 of the accompanying drawings shows an exploded view of a golf club head in accordance with yet another embodiment of the present invention. Detailed Description of the Invention

[0021] The following detailed description sets forth the best presently contemplated modes of carrying out the invention. This 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.

[0022] Various features of the invention are described below, each of which may be used independently of one another or in combination with other features, although any single feature of the invention may not address any or all of the problems discussed above, or may only address one of the problems discussed above. Furthermore, one or more of the problems discussed above may not be fully addressed by any of the features described below.

[0023] FIG. 1 of the accompanying drawings shows a front view of a golf club head 100 according to an exemplary embodiment of the present invention. First and foremost, FIG. 1 of the accompanying drawings shows a coordinate system 101 that defines the orientation of the golf club head 100 along the x, y, and z axes. The x-axis shown here is horizontal and extends in a heel-to-toe direction, with the positive axis pointing to the heel of the golf club head 100. The y-axis shown here is vertical and extends in a crown-to-sole direction. Finally, the z-axis shown here refers to an axis that spans the front-to-back direction on the page, with the positive axis pointing in the forward direction. This front view of the golf club head 100 shows a striking face portion 102, which in this embodiment is further comprised of a face insert 104 and a face perimeter 106. FIG. 1 of the accompanying drawings also shows a vertical cut line A-A' along the y-axis and along the yz plane, which allows the internal shape of the striking face portion 102 to be more clearly shown.

[0024] FIG. 2 of the accompanying drawings shows a cross-sectional view of a golf club head 200 along the section line A-A' shown in FIG. 1. In this cross-sectional view of the golf club head 200 shown in FIG. 2, it can be seen that the golf club head 200 has a striking face portion 202 and a rear body portion 203 attached to the rear of the striking face portion 202. The striking face portion 202 as defined in this invention refers to a portion of the golf club head 200 that is substantially planar, located at the front of the golf club head 200, and adapted to strike a golf ball. The striking face portion 202 is manufactured with a thickness formed by a substantially flat front striking surface 210 and a rear inner surface 212 with a variable contour, forming a striking face portion with a variable face thickness profile. The boundary between the striking face portion 202 and the rear body portion 203 occurs when the rear inner surface 212 deviates from a substantially planar vertical direction toward a substantially horizontal direction.

[0025] 2 of the accompanying drawings finally shows that in this embodiment, a face insert 204 is used to close the opening in the striking face portion 202 created by the face perimeter 206. In this embodiment of the invention, the face insert 204 may generally be made from a titanium material to achieve lightweight and durable characteristics, and may be significantly thinner than a conventional golf club head having a similar structure due to the unique thickened stress reduction region 216 around the face perimeter 206. In this embodiment of the invention, the thickened stress reduction region 220 around the face perimeter 206 allows the face insert 204 to be thinner and lighter, resulting in a mass of less than about 25 grams, more preferably less than about 24 grams, and most preferably less than about 23 grams, all without departing from the scope and content of the present invention. The mass of the face insert is reduced by about 12 grams compared to a face insert installed without the thickened stress reduction region 220 around the face perimeter 206.

[0026] To more fully illustrate the thickened stress reduction regions 220 around the face perimeter 206, along with the geometry of the remainder of the striking face portion 202, such as the thickened central region 214, the central transition region 216, the thinned intermediate region 218, and the thinned peripheral region 222, an enlarged view of the striking face portion 202 is provided in FIG. 3.

[0027] FIG. 3 of the accompanying drawings shows an enlarged cross-sectional view of the striking face portion 202 of the golf club head 200. This enlarged cross-sectional view makes it possible to more clearly show the various heights of the striking face portion 202, while FIG. 4 of the accompanying drawings shows the various thicknesses of the striking face portion 202. In accordance with this illustrated exemplary embodiment of the present invention, the striking face portion 202 further includes a thin-walled upper peripheral region 222-a and a thin-walled lower peripheral region 222-b, which combine to form the thin-walled peripheral region 222. The striking face portion 202 has an upper thick-walled stress reduction region 220-a and a lower thick-walled stress reduction region 220-b positioned inwardly from the thin-walled peripheral region and combining to form the thick-walled stress reduction region 220. In other words, the thick-walled stress reduction region 220 can be said to form a ring that projects rearwardly from the inner surface 212 of the striking face portion 202. The striking face portion 202 has an upper thinned intermediate region 218-a and a lower thinned intermediate region 218-b positioned inboard of the thickened stress reduction region and combining to form a thinned intermediate region 218. The striking face portion 202 has an upper central transition region 216-a and a lower central transition region 216-b positioned inboard from the thinned intermediate region and combining to form a central transition region 216. Finally, the striking face portion 202 includes a thickened central region 214 positioned inboard of the central transition region 214.

[0028] In this embodiment of the invention shown in FIG. 3, the height H1 of thickened central region 214 is generally between about 4.0 mm and about 15.0 mm, more preferably between about 4.0 mm and about 10.0 mm, and most preferably about 4.0 mm.

[0029] The height of the central transition region 216 may be greater below the thickened central region 214 than above the thickened central region 214, according to this embodiment of the invention. Thus, according to this embodiment, the height H2-a of the upper central transition region 216-a is between about 7.0 mm and about 11.0 mm, more preferably between about 8.0 mm and about 10.0 mm, and most preferably about 9.0 mm. The height H2-b of the lower central transition region 216-b may generally be between about 13.0 mm and about 17.0 mm, more preferably between about 14.0 mm and about 16.0 mm, and most preferably about 15.0 mm. However, it should be noted that in alternative embodiments, the heights of the upper central transition region 216-a and the lower central transition region 216-b may be the same without departing from the scope and content of the present invention.

[0030] According to this embodiment of the invention, the height of the thin intermediate region 218 may also be greater below the thick central region 214 than above the thick central region 214. Thus, according to this embodiment, the height H3-a may generally be between about 3.5 mm and about 5.5 mm, more preferably between about 4.0 mm and about 5.0 mm, and most preferably about 4.5 mm. The height H3-b of the lower central transition region 218-b may generally be between about 6.5 mm and about 8.5 mm, more preferably between about 7.0 mm and about 8.0 mm, and most preferably about 7.5 mm. However, it should be noted that in larger embodiments, the heights of the upper central transition region 218-a and the lower central transition region 218-b may be the same without departing from the scope and content of the present invention.

[0031] The height of the thickened stress reduction region 220, unlike the previous measurements, is the same measurement whether the measurement is for the upper thickened stress reduction region 220-a or the lower thickened stress reduction region 220-b. Thus, according to this embodiment, the heights H4-a and H4-b are both about 4.0 mm to about 6.0 mm, more preferably about 4.5 mm to about 5.5 mm, and most preferably about 5.0 mm. Similar to the logic above, having different H4-a and H4-b values ​​does not depart from the scope and content of the invention as long as both are within the above ranges. It is worth noting here that the height of the thickened stress reduction region 220 is important to the proper functioning of the invention, as it carefully balances the desire to avoid adding too much unnecessary mass to the striking face portion 202 and provide enough structural rigidity to reduce stress from the face perimeter 106 (shown in FIG. 1) to allow the remainder of the striking face portion 202 to be thinner and more efficient. The height of the thickened stress reduced regions 220 combined with the thickness of the thickened stress reduced regions 220 (described below in FIG. 4) outlines an optimized shape that achieves the performance enhancements of the present invention.

[0032] Before moving to a discussion of the thin peripheral regions 222, it is important to note that the location of the thicker stress reduced regions 220 relative to the geometric face center 108 (shown in FIG. 1) is critical to achieving the performance enhancements of the present invention. This is particularly true along a vertical cross-sectional plane passing through the geometric face center 108 (shown in FIG. 1), as depicted in the enlarged cross-sectional view shown in FIG. 3. The importance of this particular cross-section, and the location of the thicker stress reduced regions 220 along this cross-section, stems from the tendency of the striking face portion 202 to achieve a higher stress enhancement in the upper face portion along this plane, thus adding the thicker stress reduced regions 220. In this embodiment of the invention, the thickened stress reduction region 220 may generally be positioned along cross-sectional plane A-A' at a distance of about 15 mm to about 30 mm from the geometric face center 108 (shown in FIG. 1), preferably about 17 mm to about 28 mm from the geometric face center 108 (shown in FIG. 1) along cross-sectional plane A-A', and most preferably between about 20 mm to about 25 mm from the geometric face center 108 (shown in FIG. 1) along cross-sectional plane A-A'.

[0033] The height of the thinned peripheral region 222 may also be greater below the thickened central region 214 than above it. Thus, according to this embodiment, the height H5-a may be between about 1.8 mm and about 2.8 mm, more preferably between about 2.1 mm and about 2.5 mm, and most preferably about 2.3 mm. The height H5-b may generally be between about 2.3 mm and about 3.3 mm, more preferably between about 2.6 mm and about 3.0 mm, and most preferably about 2.8 mm. However, it should be noted that in alternative embodiments, the heights of the upper thinned peripheral region 222-a and the lower thinned peripheral region 222-b may be the same without departing from the scope and content of the present invention.

[0034] 4 of the accompanying drawings shows another enlarged cross-sectional view of the striking face portion 202 of the golf club head 200. In this cross-sectional view, the various thicknesses of the components of the striking face portion 202 are shown in more detail. In this current embodiment of the invention, the thickened central region 214 may generally have a thickness T1 of less than about 3.6 mm, more preferably less than about 3.4 mm, and most preferably less than about 3.2 mm. Since it is an object of the invention to minimize the thicknesses of the various components of the striking face portion 202 through the introduction of thickened stress reduction regions 220 that relieve stresses on the striking face portion 202.

[0035] The thickness of the thinned intermediate region 218 may be generally the same regardless of whether it is located in the upper thinned intermediate region 218-a or the lower thinned intermediate region 218-b. Thus, the thicknesses T3-a and T3-b are both less than about 2.5 mm, more preferably less than about 2.4 mm, and most preferably less than about 2.3 mm. However, in alternative embodiments of the present invention, the values ​​of T3-a and T3-b may be slightly different from each other without departing from the scope and content of the present invention as long as both are within the above ranges.

[0036] The thickness of the thick stress reduction region 220, shown here as the upper thick stress reduction region 220-a having a thickness T4-a and the lower thick stress reduction region 220-b having a thickness T4-b, in combination with the width of the thick stress reduction region 220, defines a geometry that is important for improved performance of the striking face portion 202 of the golf club head. In this embodiment, the thicknesses T4-a and T4-b of the upper thick stress reduction region 220-a and the lower thick stress reduction region 220-b, respectively, are both the same and thus are between about 3.6 mm and about 4.4 mm, more preferably between about 3.8 mm and about 4.2 mm, and most preferably about 4.0 mm. However, in other embodiments of the present invention, the thicknesses T4-a and T4-b may deviate slightly from each other without departing from the scope and content of the present invention, so long as they do not fall outside the thickness ranges defined above.

[0037] Once the thickness T4 and height H4 of the thickened stress reduced region 220 are defined, a preferred geometry for the thickened stress reduced region 220 can be established as a ratio of thickness to height. The preferred geometry has a T to H ratio defined by the following equation (1): T to H ratio = (thickness of thick stress reduced area T4) / (height of thick stress reduced area H4) ---Formula (1) The T to H ratio of the thickened stress reduced region 220 of the striking face portion 202 in accordance with the present invention may generally be between about 0.6 and about 1.1, more preferably between about 0.7 and about 0.9, and most preferably about 0.8. Again, as discussed above, this ratio is important to achieve the stress reducing properties of the striking face portion 202 while minimizing unnecessary mass added by the addition of the thickened stress reduced region 220.

[0038] The thickness of the thinned peripheral region 222 may be generally the same regardless of whether it is located in the upper thinned peripheral region 22-a or the lower thinned peripheral region 222-b. Thus, the thicknesses T5-a and T5-b are both less than about 3.0 mm, more preferably less than about 2.8 mm, and most preferably less than about 2.7 mm. However, in alternative embodiments of the present invention, the values ​​of T5-a and T5-b may be slightly different from each other without departing from the scope and content of the present invention as long as both are within the above-mentioned ranges.

[0039] Another important relationship worth highlighting here is the thickness T1 of the thickened central region 714 relative to the thickness T4 of the thickened stress reduced region 720. The resulting relationship between the two thicknesses is very important to achieve the improved performance of the present invention, since the introduction of the thickened stress reduced region 720 results in a significant overall reduction in the thickness and mass of the entire striking face portion 702. In this exemplary embodiment of the present invention, the ratio of T4 divided by T1 is generally greater than about 1, more preferably greater than about 1.15, and most preferably greater than about 1.375. Stated another way, it can be said that the thickness T4 of the thickened stress reduced region 220 is greater than the thickness T1 of the thickened central region 214, or any other location along the entire striking face portion 202. The thickest portion of the striking face portion 202 is located on the thickened stress reduced region 220.

[0040] FIG. 5 of the accompanying drawings shows an enlarged cross-sectional view of the striking face portion 202 of the golf club head 200 similar to FIGS. 3 and 4, but this time focusing on the transition from the thicker stress reduction region 220 to the adjacent thinner intermediate region 218 and thinner peripheral region 222. In this embodiment of the invention, the various radii around the thicker stress reduction region 220 are also important to the proper functioning of the invention, as undesirable radii not only do not serve the purpose of reducing stress, but can also add manufacturing challenges. Above all, the radii must balance the stresses and manufacturing challenges caused by the thicker stress reduction region 220 with minimizing the addition of undesirable weight due to the addition of the thicker stress reduction region 220 on the one hand.

[0041] Radius R5-a and radius R5-b represent the radius of curvature or blend from the thicker stress reduction regions 220-a and 220-b to the thinner peripheral regions 222-a and 222-b. R5-a and R5-b in this embodiment may generally be the same number, typically about 1.0 mm to about 1.4 mm, more preferably about 1.1 mm to about 1.3 mm, and most preferably about 1.2 mm. However, it should be noted that in other embodiments of the invention, R5-a and R5-b may be different from each other as long as they are within the radius ranges stated above without departing from the scope and content of the invention.

[0042] Radius R3-a and radius R3-b represent the radius of curvature or blend from the thicker stress reduction regions 220-a and 220-b to the thinner intermediate regions 218-a and 218-b. R3-a and R3-b in this embodiment may generally be the same as or may be the same as R5-a and R5-b described above, and may be between about 1.0 mm and about 1.4 mm, more preferably between about 1.1 mm and about 1.3 mm, and most preferably about 1.2 mm. However, it should be noted that in other embodiments of the invention, R3-a and R3-b may be different from one another as long as they are within the radius ranges described above without departing from the scope and content of the invention.

[0043] It is instructive to note here that the radii of blends from the thicker stress reduced region 220 to the thinner peripheral region 222 and the thinner intermediate region 218, designated R5 and R3, respectively, may generally be the same as one another, although, as noted above, in other embodiments of the invention, these numbers may be different from one another without departing from the scope and content of the invention, so long as they are within the ranges set forth above.

[0044] 6a to 6L of the accompanying drawings show alternative shapes of the thickened stress reduction region 220. Referring to FIG. 6a, a substantially rectangular design is shown here, similar to the previous design with the addition of a transition radius. FIG. 6b of the accompanying drawings shows an alternative outward taper design of the thickened stress reduction region 220 according to an alternative embodiment of the present invention. FIG. 6c of the accompanying drawings shows another inward taper design of the thickened stress reduction region 220 according to an alternative embodiment of the present invention. FIG. 6d of the accompanying drawings shows an alternative outward taper with a certain offset design of the thickened stress reduction region 220 according to an alternative embodiment of the present invention. FIG. 6e of the accompanying drawings shows an alternative outward taper with an inward offset design of the thickened stress reduction region 220 according to an alternative embodiment of the present invention. FIG. 6f of the accompanying drawings shows an alternative outward taper with an outward offset design of the thickened stress reduction region 220 according to an alternative embodiment of the present invention. FIG. 6g of the accompanying drawings illustrates an alternative triangular chevron design of the thickened stress reduction region 220 according to an alternative embodiment of the present invention. FIG. 6h of the accompanying drawings illustrates an alternative inward offset triangular chevron design of the thickened stress reduction region 220 according to an alternative embodiment of the present invention. FIG. 6i of the accompanying drawings illustrates an alternative outward offset triangular chevron design of the thickened stress reduction region 220 according to an alternative embodiment of the present invention. FIG. 6j of the accompanying drawings illustrates an alternative hemispherical design of the thickened stress reduction region 220 according to an alternative embodiment of the present invention. FIG. 6k of the accompanying drawings illustrates an alternative organic design of the thickened stress reduction region 220 according to an alternative embodiment of the present invention. FIG. 6L of the accompanying drawings illustrates an alternative recessed channel tapered design of the thickened stress reduction region 220 according to an alternative embodiment of the present invention.

[0045] 7a and 7b show rear views of a striking face portion 702 of a golf club head in accordance with an exemplary embodiment of the present invention. In FIG. 7a, a shaded view is provided to better visualize the various components of the striking face portion 702. In FIG. 7a, a thin peripheral region 722 forms the perimeter of the striking face portion 702. Inward from the thin peripheral region 722, a thicker stress reduction region 720 can be seen. Inward from the thicker stress reduction region 720 is a thin intermediate region 718. Inward from the thin intermediate region 718 is a central transition region 716. Finally, at the geometric center of the striking face portion 702 is a thicker central region 714. In addition to showing the various components of the striking face portion 702, FIG. 7a also shows how the height of the various components varies depending on where they are on the face, as previous measurements of the height of the various components only referenced a cross section along the geometric center of the face, as shown in FIG. 1. In one example, it can be seen that the height of the intermediate transition region 718 is generally less at the crown and sole portions of the striking face portion 702 as compared to the height of the intermediate transition region 718 at the heel and toe portions of the striking face portion 702 .

[0046] Stated another way, the striking face can be said to have a thickened central region 714 located near the geometric center of the striking face portion 702, a central region 716 extending radially outward from the thickened central region 714, a thinned intermediate region 718 extending radially outward from the thickened central region 714, a thickened stress reduction region 720 extending radially outward from the thickened central region 714, and finally, a thinned peripheral region 722 extending outward from the thickened stress reduction region 720.

[0047] To better illustrate the differences in height of the various components along various portions of the face, FIG. 7b illustrates an unshaded rear view of the striking face portion 702. In addition to the above, FIG. 7b allows for a more detailed illustration of the radial distances of the various components, since all measurements are taken from the geometric face center 108 (shown in FIG. 1). This is similar to the above discussion regarding the location of the thickened stress reduced region 220 in FIG. 2. However, the distances provided here are not bound to a particular cross section A-A', as in the previous discussion in FIG. 2, but rather are measurements of minimum and maximum radial distances. In this rear view of the striking face portion 702 shown in FIG. 7b, it can be seen that the outer periphery of the thickened central region 714 is generally located within a projected distance D1 of between about 4.00 mm and about 14.0 mm from the geometric face center over any radial direction. The periphery of the central transition region 716 may generally be located at a distance D2 between about 13.0 mm and about 30.0 mm from the geometric face center in any radial direction. The periphery of the thinned intermediate region 718 may generally be located at a distance D3 between about 17.0 mm and about 40.0 mm from the face center in any radial direction. The periphery of the thickened stress reduction region 720 may generally be located at a distance D4 between about 15.0 mm and about 46.0 mm from the face center in any radial direction. Finally, the periphery of the thinned peripheral region 722 may generally be located at a distance D5 between about 25.50 mm and about 55.5 mm from the face center in any radial direction.

[0048] Figure 8 of the accompanying drawings shows a cross-sectional view of a golf club head 800 in accordance with an alternative embodiment of the present invention taken along section line A-A' shown in Figure 1. In this cross-sectional view of the present invention, the shape and geometry of the upper thickened stress reduction region 820-a is modified differently than the lower thickened stress reduction region 820-b to help address the high stress levels generally encountered in the upper crown region of the striking face portion 802. An enlarged view of the striking face portion 802 is provided in Figure 9 to show the difference in blend height and radius of curvature between the upper thickened stress reduction region 820-a and the lower thickened stress reduction region 820-b.

[0049] FIG. 9 of the accompanying drawings shows an enlarged view of the cross section of the striking face portion 802 of the golf club head 800 shown in FIG. 8. In this enlarged cross section, only the features that distinguish this embodiment of the invention from the previous embodiment are highlighted. In this alternative embodiment of the invention, the height H4-a of the upper thick stress reduction region 820-a is no longer the same as the height H4-b of the lower thick stress reduction region 820-b. In fact, the height H4-a of the upper thick stress reduction region 820-a is reduced to address stress risers that often occur at the upper portion of the striking face portion 802. As the upper stress reduction region 820-a becomes thicker, the height H3-a of the upper thin intermediate region 818-a increases. In addition to the points mentioned above, to further reduce stress, the radius R3-a between the upper thick stress reduction region 820-a and the upper thin intermediate region 818-a is increased to create a more gradual blend at this location. Finally, regardless of addressing stress levels in the striking face portion 802, the radius R5-a between the upper, thicker stress reduced region 820-a and the upper, thinner peripheral region 822-a can also be increased to soften the blend and facilitate manufacturability.

[0050] Breaking down the numbers, the height H4-a of the upper, thicker stress reduction region 820-a according to this embodiment of the invention may generally be between about 3.1 mm and about 3.9 mm, more preferably between about 3.3 mm and about 3.7 mm, and most preferably about 3.5 mm, which is about 0.5 mm shorter than the corresponding portion H4-b located in the lower, thicker stress reduction region 820-b. The height H3-a of the upper, thin-walled intermediate region 818-a according to the current embodiment of the invention may generally be between about 6.5 mm and about 8.5 mm, more preferably between about 7.0 mm and about 8.0 mm, and most preferably about 7.5 mm, which is approximately the same as the corresponding portion H3-b located in the lower, thin-walled intermediate region 818-b.

[0051] In addition to the change in height, the radii R3-a and R5-a of the upper thickened stress reduction region 820-a are also modified to be different from the corresponding portions of the lower thickened stress reduction region 820-b. Increasing the radius of curvature of R3-a provides a more gradual transition between the two adjacent components, helping to eliminate stress risers that may occur in that portion of the striking face portion 802. R3-a according to this embodiment of the invention may generally be greater than about 1.50 mm, more preferably greater than about 1.60 mm, and more preferably greater than about 1.70 mm. On the other hand, the radius of curvature R5-a is also increased to be more gradual, but this time to allow for a less noticeable area of ​​reduced casting flow for manufacturing reasons. Thus, R5-a according to this embodiment of the invention may generally be greater than about 1.50 mm, more preferably greater than about 1.60 mm, and more preferably greater than about 1.70 mm. It is therefore worth noting here that in this embodiment it is important that the radius of curvature of the transition of the upper, thicker stress reduced region 820-a is greater than the radius of curvature of the transition of the lower, thicker stress reduced region 820-b, since the striking face portion 802 often exhibits higher stress levels at that location.

[0052] 10a and 10b show rear views of a striking face portion 1002 of a golf club head according to an exemplary embodiment of the present invention. In FIG. 10a, a shaded view is presented to provide a better visualization of the various components of the striking face portion 1002. In the shaded view shown in FIG. 10a and the wireframe view shown in FIG. 10b, an adjustment to the upper thick stress reduction region 1020-a is seen, whose height H4-a (shown in FIG. 9) is smaller compared to the remaining portion of the thick stress reduction region 1020-a. Another thing worth noting here that has not been mentioned before is that in the current exemplary embodiment of the present invention, the entire thick stress reduction region 1020 takes the shape of a ring surrounding the central portion of the striking face portion 1002. However, in alternative embodiments of the present invention, the thick stress reduction region 1020 need not completely surround the striking face portion 1002, but may partially surround the striking face portion without departing from the scope and content of the present invention. Stated another way, the thickened stress reduction region 1020 may encompass less than 360 degrees around the face, less than about 270 degrees around the face, or less than 180 degrees around the face, all without departing from the scope and content of this invention.

[0053] Figures 11 through 15 of the accompanying drawings show a golf club head in accordance with yet another embodiment of the present invention, wherein the thickened stress reduction region is formed from multiple materials to achieve further improved stress reduction capabilities of the thickened stress reduction region.

[0054] Figure 11 of the accompanying drawings shows an exploded perspective view of a golf club head 1100 in accordance with yet another embodiment of the present invention, where the thickened stress reduction region is further formed from multiple materials. In this exploded cross-sectional view of the golf club head 1100 shown in Figure 11, the body portion 1103 has a pocket 1134 with a perimeter ledge 1132 that helps to receive a gasket 1130 that separates the face insert 1104 from the perimeter ledge 1132, as shown in Figure 11. In this embodiment of the present invention, the combination of the perimeter ledge 1132, the gasket 1130, and the perimeter of the face insert 1104 combine to create the thickened stress reduction region (shown in Figure 12).

[0055] [FIG. 12 of the accompanying drawings shows a cross-sectional view of a golf club head 1200 in accordance with an alternative embodiment of the present invention, taken along section line A-A' as shown in FIG. 1. In this cross-sectional view of the golf club head 1200, it can be seen that the golf club head 1200 can be divided into a front striking face portion 1202 and a rear body portion 1203, similar to the previous embodiment. The front striking face portion 1202 further comprises an open pocket 1234 adapted to receive a face insert 1204, as in the previous embodiment. However, in this embodiment of the present invention, instead of directly welding the face insert 1204 to the perimeter of the pocket 1234 as is commonly known in the industry, the open pocket 1234 creates a peripheral ledge 1232 recessed from the outer surface of the striking face, which peripheral ledge 1232 is adapted to receive a gasket 1230 that separates the face insert 1204 from the peripheral ledge 1232. In this cross-sectional view of the invention, it can be clearly seen that the combination of the peripheral ledge 1232, the gasket 1230, and the periphery of the face insert 1204 combine to create the thickened stress reduced region 1220. The thickened stress reduced region 1220 in this embodiment may be further defined as an upper thickened stress reduced region 1220-a and a lower thickened stress reduced region 1220-b, both of which have similar dimensional measurements as the previous embodiments described above.

[0056] In this embodiment of the invention, the face insert 1204, gasket 1230, and peripheral ledge 1232 may generally be bonded together using some type of adhesive, although in alternative embodiments of the invention, the three components forming the thickened stress reduced region 1220 may have different material properties and may rely on a variety of bonding techniques, such as brazing, swaging, or mechanical fasteners, all without departing from the scope and content of the invention, so long as the face insert 1204 is not directly bonded to the peripheral ledge 1232 itself.

[0057] The material used to construct the gasket 1230 is also important in this embodiment of the invention and can help reduce stress around the front striking face portion 1202. In this embodiment, the material used to construct the gasket may generally have a modulus of elasticity, or Young's modulus, of between about 5 GPa and about 120 GPa, more preferably between about 10 GPa and about 80 GPa, and most preferably about 30 GPa. In addition to the above, the gasket 1230 may also have a density of less than about 2,000 g / cc, more preferably less than about 1,900 g / cc, and most preferably less than about 1,800 g / cc, all without departing from the scope and content of the present invention.

[0058] To illustrate some of the dimensions of the gasket 1230 itself, an enlarged cross-sectional view of the front striking face portion 1202 is shown in FIG. 13. In this portion shown in FIG. 13, it can be seen that the gasket 1230 can have an upper gasket height H6-a and a lower gasket height H6-b that are approximately the same. H6-a and H6-b according to this embodiment of the invention can generally be between about 3.0 mm and about 7.0 mm, more preferably between about 4.0 mm and about 6.0 mm, and most preferably about 5.0 mm. FIG. 13 also shows the gasket thickness T6, which is shown as the upper gasket thickness T6-a and the lower gasket thickness T6-b, both of which are approximately the same in this embodiment of the invention. Thus, T6-a and T6-b according to this embodiment of the invention can generally be between about 0.3 mm and about 0.7 mm, more preferably between about 0.4 mm and about 0.6 mm, and most preferably about 0.5 mm.

[0059] Based on the thickness and height measurements above, it can be said that the gasket 1230 can have a T to H ratio defined by equation (2) below: T to H ratio = (gasket thickness T6) / (gasket height H6) ----- (2) The T to H ratio of the gasket 1230 may generally be between about 0.04 and about 0.23, more preferably between about 0.06 and about 0.15, and most preferably about 0.1.

[0060] It should also be noted that although the thickness and height of the gasket 1230 are the same for the top portion of the gasket 1230 and the bottom portion of the gasket 1230, the thickness and height of the gasket may be different from each other. This does not depart from the scope and content of the present invention. In one exemplary embodiment, the top portion of the gasket 1230 can be made thicker and the bottom portion of the gasket 1230 can be made thinner to help the striking face portion 1202 flex more downward upon impact with the golf ball, reducing downward launch and spin, without departing from the scope and content of the present invention. Of course, when manipulating the thickness of the gasket 1230, the depth of the perimeter ledge 1232 is typically adjusted accordingly to create a seamless flat appearance of the golf club head in the rest neutral position. Alternatively, the thickness of the material can be maintained, but the modulus of elasticity adjusted to achieve the same effect without departing from the scope and content of the present invention.

[0061] Figure 14 of the accompanying drawings shows a rear view of a striking face portion 1402 of a golf club head in accordance with a further alternative embodiment of the present invention. In this embodiment of the present invention shown in Figure 14, it can be seen that the front striking face portion 1402 can include a thickened stress reduction region 1420 that only partially forms a portion of a ring, as shown in the previous embodiment. More specifically, the thickened stress reduction region 1420 shown in this embodiment of the present invention shown in Figure 14 is only present in the upper crown region and lower sole region, via an upper thickened stress reduction region 1420-a and a lower thickened stress reduction region 1420-b.

[0062] The back view of the striking face portion 1402 shown now in FIG. 14 shows the thick central region 1414, the central transition region 1416, the thin intermediate region 1418, and the thin peripheral region 1422, in addition to the upper thick stress reduced region 1420-a and the lower thick stress reduced region 1420-b. This back view of the striking face portion 1402 shows that the upper thick stress reduced region 1420-a and the lower thick stress reduced region 1420-b join together to form only a portion of a ring shape as previously shown in FIG. 7. In other words, the thick stress reduced region 1420 does not completely surround the thin intermediate region 1418, but only partially. It can also be said that the thick stress reduced region forms less than 360 degrees radially around the thin intermediate region 1418.

[0063] In addition to visually highlighting the currently separated upper thick stress reduced region 1420-a and lower thick stress reduced region 1420-b, FIG. 14 of the accompanying drawings also creates a light ray marking (clock grid) 1440 to more specifically identify the location of the upper thick stress reduced region 1420-a and lower thick stress reduced region 1420-b relative to the geometric face center 1408. More specifically, the light markings 1440 include a 12 o'clock light marking 1440-12, a 1 o'clock light marking 1440-1, a 2 o'clock light marking 1440-2, a 3 o'clock light marking 1440-3, a 4 o'clock light marking 1440-4, a 5 o'clock light marking 1440-5, a 6 o'clock light marking 1440-6, a 7 o'clock light marking 1440-7, an 8 o'clock light marking 1440-8, a 9 o'clock light marking 1440-9, a 10 o'clock light marking 1440-10, and an 11 o'clock light marking 1440-11, radially dividing various portions of the striking face portion 1402 into twelve separate regions.

[0064] Once the light marks 1440 are established, it can be seen that in this exemplary embodiment of the invention, the upper thickened stress reduced region 1420-a is located in the upper region located between the 10 o'clock light mark 1440-10 and the 2 o'clock light mark 1440-2. The lower thickened stress reduced region 1420-b is located in the lower region located between the 4 o'clock light mark 1440-4 and the 8 o'clock light mark 1440-8. This range of locations for the upper thickened stress reduced region 1420-a and the lower thickened stress reduced region 1420-b is important to the invention as it maintains structural rigidity and reduces stress levels in the striking face portion 1402 only where it is identified as needed and is removed from places where such functionality is not needed.

[0065] It should be noted here that to avoid confusion when referring to ranges in this application, clock grid boundaries are always referenced in a clockwise direction.

[0066] In other words, the thick stress reduction region is located only in the region consisting of the upper region between the 10 o'clock ray mark 1440-10 and the 2 o'clock ray mark 1440-2, and the lower region between the 4 o'clock ray mark 1440-4 and the 8 o'clock ray mark 1440-8.

[0067] 15 of the accompanying drawings shows a rear view of a striking face portion 1502 of a golf club head according to a further alternative embodiment of the present invention. In this embodiment of the present invention, the upper thick-walled stress reduction region 1520-a is located in the upper region between the 9 o'clock ray mark 1540-9 and the 2 o'clock ray mark, while the lower thick-walled stress reduction region 1520-b is located in the lower region between the 3 o'clock ray mark 1540-3 and the 9 o'clock ray mark 1540-9, without departing from the scope and content of the present invention. Here, it should be noted that the boundaries of the upper thick-walled stress reduction region 1520-a and the lower thick-walled stress reduction region 1520-b may have some overlap with each other, and they are separate components with separation, which remains within the scope and content of the present invention.

[0068] In other words, the thick stress reduction region is located only in the region consisting of the upper region between the 9 o'clock ray mark 1540-9 and the 2 o'clock ray mark 1540-2 and the lower region between the 3 o'clock ray mark 1540-3 and the 9 o'clock ray mark 1540-9.

[0069] 16 of the accompanying drawings shows an enlarged cross-sectional view of a striking face portion 1602 according to an alternative embodiment of the present invention, in which the non-360 degree thickened stress reduced region 1620 can be seen in more detail. In this view, it can be seen that the actual cross-sectional view of the striking face portion 1602, including the upper thinned intermediate region 1618-a, the lower thinned intermediate region 1618-b, the upper thickened stress reduced region 1620-a, the lower thickened stress reduced region 1620-b, the upper thinned peripheral region 1622-a, and the lower thinned peripheral region 1622-b, is not significantly different from the cross-sectional view of the striking face portion 802 shown in FIG. 9 in the previous embodiment of the present invention. However, upon closer inspection of the cross-sectional view of the striking face portion 1602, it can be seen that the inner toe region of the striking face portion 1602 does not include any features similar to the thickened stress reduced region 1620 as in the previous embodiment shown in FIGS. 14 and 15.

[0070] 17 of the accompanying drawings shows a rear view of a striking face portion 1702 of a golf club head in accordance with yet another alternative embodiment of the present invention. In this embodiment of the present invention, a familiar clock grid 1740 can be seen having a 12 o'clock mark 1740-12, a 1 o'clock mark 1740-1, a 2 o'clock mark 1740-2, a 3 o'clock mark 1740-3, a 4 o'clock mark 1740-4, a 5 o'clock mark 1740-5, a 6 o'clock mark 1740-6, a 7 o'clock mark 1740-7, an 8 o'clock mark 1740-8, a 9 o'clock mark 1740-9, a 10 o'clock mark 1740-10, and an 11 o'clock mark 1740-11, which divides various portions of the striking face portion 1702 radially into twelve separate regions. However, unlike the previous embodiment in which the thickened stress reduced regions 1420 (shown in FIG. 14 ) disappear completely in the heel and toe portions of the striking face portion 1702, the thickened stress reduced regions 1720 shown in FIG. 17 maintain a minimal wall thickness in the heel and toe portions of the striking face portion 1702.

[0071] In this embodiment of the invention shown in FIG. 17, the thick stress reduced region 1720 is one continuous structure that includes upper thick stress reduced region 1720-a, lower thick stress reduced region 1720-b, toe thick stress reduced region 1720-c, and heel thick stress reduced region 1720-d, where the toe thick stress reduced region 1720-c and heel thick stress reduced region 1720-d have relatively smaller thicknesses compared to the upper thick stress reduced region 1720-a and lower thick stress reduced region 1720-a.

[0072] In other words, in this embodiment of the invention, the thickened stress reduced region may include a region of reduced thickness between the 1 o'clock light mark 1740-1 and the 4 o'clock light mark 1740-1 to form the toe thickened stress reduced region 1720-c, and a region of reduced thickness between the 8 o'clock light mark 1740-8 and the 10 o'clock light mark 1740-10 to form the heel thickened stress reduced region 1720-d.

[0073] 18 of the accompanying drawings shows an enlarged cross-sectional view of a striking face portion 1802 in accordance with an alternative embodiment of the present invention, which may show in greater detail the reduced thickness thick stress reduced region 1820. As with the previous embodiment, this cross-sectional view of the striking face portion 1802 includes an upper thin intermediate region 1818-a, a lower thin intermediate region 1818-b, an upper thick stress reduced region 1820-a, a lower thick stress reduced region 1820-b, an upper thin peripheral region 1822-a, and a lower thin peripheral region 1822-b. However, this view shown in FIG. 18 may show the reduced thickness of the toe thick stress reduced region 1820-c.

[0074] FIG. 19 of the accompanying drawings shows a rear view of a striking face portion 1902 of a golf club head in accordance with yet another embodiment of the present invention. In this embodiment of the present invention, a thickened stress reduction region 1920 radiates outward from the thinned intermediate region 1918. However, in this embodiment of the present invention, the thickened stress reduction region 1920 comprises a horseshoe shape rather than a ring shape, which helps to accommodate a differently shaped face insert 1904, which may improve the performance of the striking face portion 1902. More specifically, it can be seen from FIG. 19 that the thickened stress reduction region 1920 may comprise two upper stress reduction regions 1920a designated as a toe side upper thick stress reduction region 1920-a1 and a heel side upper thick stress reduction region 1920-a2. It should be noted that the toe side upper thick stress reduced region 1920-a1 and the heel side upper thick stress reduced region 1920-a2 both connect directly to the crown transition portion of the striking face portion 1902. That is, they do not connect directly to each other at the crown portion of the striking face portion 1902 to form a complete ring, but rather create a discontinuity that forms an incomplete circle. Alternatively, the stress reduced region 1920 may be said to form the horseshoe shape described above. As a result, the thickening of the horseshoe shaped stress reduced region 1920 forms an opening near the upper crown portion of the striking face portion 1902.

[0075] Here, the toe side upper thick stress reduced region 1920-a1 is connected to the toe side thick stress reduced region 1920-c at the toe side of the striking face portion 1902, which is connected to the lower thick stress reduced region 1920-b at the sole side of the striking face portion 1902, which is connected to the heel side thick stress reduced region 1920-d, but remains disconnected at the upper crown region of the striking face portion 1902 to accommodate the taller face insert 1904. This face insert 1904 is designed to be taller at the center region of the face insert 1904, which helps move the weld line between the face insert 1904 and the perimeter region 1903 (shown in FIG. 20) further away from the locations that generate high stress in this current design. To further illustrate the shape of the perimeter region 1903 and the central opening 2050 (shown in FIG. 20), FIG. 20 shows the face insert 1904 removed.

[0076] Finally, it can be seen in Figure 20 that the section line 22-22' is drawn vertically through the striking face portion 1902 such that it passes through the geometric face center 1908 of the striking face portion 1902. The cross-sectional view of the striking face portion 1902 of the golf club head in Figure 22, shown below, will allow the various dimensions of the striking face portion 1902 to be shown in more detail later.

[0077] FIG. 20 of the accompanying drawings shows a rear view of a striking face portion 2002 of a golf club head according to yet another embodiment of the present invention, but with the face insert 1904 shown in FIG. 19 removed, more clearly showing the central opening 2050 along with the boundary of the face perimeter 2006. The striking face portion 2002 shown in FIG. 20 includes a central opening 2050 that is mated with the horseshoe shaped thickened stress reduced area 2020 and therefore substantially coincides with the inner perimeter of the horseshoe shaped thickened stress reduced area 2020. In addition to showing the boundary of the central opening 2050, FIG. 20 of the accompanying drawings also shows the distance from the top ledge of the central opening 2050 to the crown tip of the striking face portion 2002, which distance is shown as distance D6. Distance D6 shown in FIG. 20 shows how the distance is reduced compared to conventional golf club heads, and is generally less than about 1.25 mm, more preferably less than about 1.00 mm, and most preferably less than about 0.95 mm. Distance D6, as shown in this embodiment of the invention, is generally taken on the Y axis as shown in FIG. 1, ie, the geometric center 2008 of the dashed plane as shown in FIG.

[0078] A conventionally shaped face insert 104 (see FIG. 1) typically has a substantially elliptical shape designed to match the contour of the striking face portion 102 (see FIG. 1) with an aspect ratio of about 2.0. However, the face insert 2104 according to this embodiment of the invention has a taller face and therefore an aspect ratio of about 1.3 to about 1.7, more preferably about 1.4 to about 1.6, and most preferably about 1.5. FIG. 21 of the accompanying drawings shows a rear view of only the face insert 2102 according to this alternative embodiment of the invention. The aspect ratio of the face insert 2104 can generally be defined as the ratio of the width D7 of the face insert 2104 divided by the height D8 of the face insert 2104. In this one exemplary embodiment of the invention, the width D7 of the face insert 2104 is generally between about 60 mm and about 64 mm, more preferably between about 61 mm and about 63 mm, and most preferably about 62 mm. The height D8 of the face insert 2104 is generally between about 40 mm and about 44 mm, more preferably between about 41 mm and about 43 mm, and most preferably about 42 mm. Of course, there is a central opening 2050 (shown in FIG. 20).

[0079] In other words, the striking face portion 1902 can be said to be disposed on a front portion of the golf club head adapted to strike a golf ball and a body portion attached to the rear of the striking face portion 1902. The striking face portion 1902 comprises a face perimeter 2006 having a central opening 2050, the face perimeter 2006 comprising a horseshoe shaped thickened stress reduced region 2020 comprising a fourth thickness. The striking face portion 1902 further comprises a face insert 2104 adapted to engage with the central opening 2050, the face insert 2104 comprising a thickened central region located near a geometric center 2108 of the face insert 2104 that defines a first thickness. The thickened stress reduced region 2020 in the face perimeter 2006 of the striking face portion 1902 is formed such that no portion of the thickened stress reduced region 2020 engages the face insert 2104. The fourth thickness of the thickened stress reduced region 2020 in accordance with a preferred embodiment of the present invention is greater than the first thickness of the central region of the face insert 2104.

[0080] FIG. 22 of the accompanying drawings shows an enlarged cross-sectional view of the striking face portion 2202 of the golf club head taken along the section line 22-22' shown in FIG. 19. In this cross-sectional view of the striking face portion 2202, it can be seen that the face insert 2204 is located a distance D6 away from the crown tip of the striking face portion 2202. The crown tip, as defined in this invention, is the location where the striking face portion 2202 ceases to be substantially planar with the striking face plane and begins to transition into a crown. The value of the distance D6 has already been discussed above and will not be repeated here. In addition to the distance D6, FIG. 22 of the accompanying drawings also shows a distance D9 which measures the location of the top end of the face insert 2204 measured from the crown apex 2252. The crown apex 2252 is generally defined as the highest point of the crown at the central section 22-22' shown in FIG. 19. The distance D9 shown in this exemplary embodiment of the present invention is generally less than about 10 mm, more preferably less than about 9 mm, and most preferably less than about 8 mm, any of which is within the scope and content of the present invention.

[0081] Because section line 22-21' is located at the geometric face center 1908 (see FIG. 19), the thicker stress reduced region 2220 bisects the club head at a discontinuous location, and therefore the actual thickness of the upper thicker stress reduced region is not shown in this section. However, FIG. 22 shows the thickness of the lower thicker stress reduced region 2220-b having a thickness T4-b, which is similar to the thicknesses discussed above. At the top of the club head, the thickness of the upper thicker stress reduced region 1920-a (see FIG. 19) is not visible, but the toe side upper thicker stress reduced region 2220-a1 is visible in the background, directly connected to the crown transition portion.

[0082] FIG. 22 of the accompanying drawings also shows the thickness of the upper thin peripheral region 2218-a, which has a different thickness T3-a than previous embodiments of the invention. The increased thickness of the upper thin peripheral region 2218-a is necessary to relieve some of the high stresses that occur at certain locations of the striking face portion 2202 upon impact with a golf ball. The thickness T3-a according to this alternative embodiment of the invention is typically between about 2.3 mm and about 2.6 mm, more preferably between about 2.4 mm and about 2.5 mm, and most preferably about 2.45 mm, none of which departs from the scope and content of the invention. This location of the upper thin peripheral region 2218-a typically extends further up the striking face portion 2202 than other embodiments in which the thicker stress reduction region 2220 forms an entire ring.

[0083] Figure 23 of the accompanying drawings shows an exploded perspective view of a golf club head 2300 in accordance with this alternative embodiment of the present invention. In the exploded view shown in Figure 23, the face insert 2304 has been moved from the face perimeter 2306 to expose the central opening 2350, more clearly illustrating the relationship between these joined components. In addition to the above, the exploded view of the golf club head 2300 shown in Figure 23 provides another perspective of the distance D6 between the top ledge of the central opening and the crown leading edge.

[0084] It should be noted that while most of the embodiments described herein are directed to making the hosel hole cover releasable, all of these embodiments may include adhesive to keep the hosel hole cover in the hosel hole, making the hosel hole cover non-removable, without departing from the scope and content of this invention.

[0085] Other than in the working examples, or unless otherwise indicated, all numerical ranges, amounts, values, and percentages in the preceding specification, such as amounts of materials, moments of inertia, center of gravity locations, lofts, draft angles, various performance ratios, etc., may be understood as if preceded by the term "about" even if the term "about" does not explicitly appear in the value, amount, or range. Accordingly, unless otherwise indicated, the numerical parameters set forth in the foregoing specification and appended claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and without attempting to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be construed at least in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0086] 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. However, such numerical values ​​inherently contain certain errors resulting from the standard deviation found in their respective testing measurements. Moreover, when numerical ranges of various scopes are set forth herein, it is to be noted that any combination of these values ​​inclusive of the recited values ​​may be used.

[0087] Of course, it will be understood that the foregoing relates to exemplary embodiments of the invention and that modifications can be made without departing from the spirit and scope of the invention as set forth in the following claims.

Claims

1. In the golf club head, a striking face portion located at a front portion of the golf club head and adapted to strike a golf ball; a body portion attached rearwardly of the striking face portion; The striking face portion further comprises: a substantially planar front striking surface; an inner back surface; The front striking surface and the inner rear surface in combination further comprise: a thickened central region located near a geometric center of the striking face portion, the thickened central region having a first thickness; a central transition region extending radially outward from the thickened central region and having a variable thickness; a thinned intermediate region extending radially outward from the central transition region, the thinned intermediate region having a third thickness; a thickened stress reduction region extending radially outward from the thinned intermediate region, the thickened stress reduction region having a fourth thickness; a thinned peripheral region extending radially outward from the thickened stress reduction region, the thinned peripheral region having a fifth thickness; the thickened stress reduced region forms a horseshoe shaped ring projecting rearwardly from the inner rear surface of the striking face portion; The fourth thickness is greater than the thickness of the golf club head.

2. 2. The golf club head of claim 1, wherein the opening in the horseshoe ring is located near a crown transition portion of the striking face portion.

3. The thick walled stress reduced region further comprises: Toe side upper thick stress reduction area, Toe side thick stress reduction area, Lower thick wall stress reduction area, a heel-side thick-walled stress reduction region; and A heel-side upper thick-walled stress reduction region is provided.

3. The golf club head of claim 2, wherein the toe side upper thick stress reduced region and the heel side upper thick stress reduced region are discontinuous with each other.

4. 4. The golf club head of claim 3, wherein the toe upper thickened stress reduced region is directly connected to the crown transition portion.

5. 5. The golf club head of claim 4, wherein said heel side upper thickened stress reduced region is directly connected to said crown transition portion.

6. The thickened stress reduced region has a T to H ratio of between about 0.6 and about 1.1, the T to H ratio being defined as: T-to-H ratio=(fourth thickness T4 of thick stress reduced region) / (height H4 of thick stress reduced region) 6. The golf club head according to claim 5.

7. 7. The golf club head of claim 6, wherein the T to H ratio is between about 0.7 and about 0.

9.

8. 8. The golf club head of claim 7, wherein the T to H ratio is about 0.

8.

9. a striking face portion located at the front of the golf club head adapted to impact a golf ball; a body portion attached to a rear portion of the striking face portion; The striking face portion further comprises: a peripheral region having a central opening, the peripheral region further having a thickened stress reduction region having a fourth thickness; a face insert adapted to engage the central opening; the face insert further having a thickened central region having a first thickness located near a geometric center of the striking face portion; no portion of the thickened stress reduced region engages the face insert; The fourth thickness is greater than the first thickness.

10. 10. The golf club head of claim 9, wherein the top ledge of the central opening is located less than about 1.5 mm from a crown tip of the striking face portion.

11. 11. The golf club head of claim 10, wherein the top ledge of the central opening is located less than about 1.0 mm from the crown tip of the striking face portion.

12. 12. The golf club head of claim 11, wherein the top ledge of the central opening is located less than about 0.9 mm from the crown tip of the striking face portion.

13. 11. The golf club head of claim 10, wherein the thickened central portion forms an incomplete circle.

14. 14. The golf club head of claim 13, wherein the non-circular discontinuity is disposed near a crown side of the thickened central portion.

15. 10. The golf club head of claim 9, wherein the face insert has an aspect ratio of about 1.3 to about 1.

7.

16. 16. The golf club head of claim 15, wherein the face insert has an aspect ratio of about 1.4 to about 1.

6.

17. 17. The golf club head of claim 16, wherein the face insert has an aspect ratio of about 1.

5.

18. 10. The golf club head of claim 9, wherein the top ledge of the central opening is located less than about 10 mm from the crown apex.

19. 20. The golf club head of claim 18, wherein the top ledge of the central opening is located less than about 9 mm from the crown apex.

20. 20. The golf club head of claim 19, wherein the top ledge of the central portion is located less than about 8 mm from the crown apex.

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