Golf club head with insert

Abstract

Inserts are available for golf club heads. [Solution] This specification describes embodiments of cavity-back irons having inserts. In some embodiments, the insert has multiple voids. In some embodiments, the voids may be substantially the same size. In other embodiments, the void sizes may vary to create variable density. Cavity-back irons may include undercuts, lips, or other rear structures. The insert can fill the rear cavity and most of the undercuts, lips, or retention mechanisms. In some embodiments, the insert consists of multiple pieces. In many embodiments, the insert can be press-fitted into the cavity. Other embodiments of cavity-back irons having inserts are described herein.

Description

Technical Field

[0001] (Related Application Data) This application claims the benefit of U.S. Patent Application No. 63 / 108,232, filed Oct. 30, 2020, and also claims the benefit of U.S. Patent Application No. 63 / 262,541, filed Oct. 14, 2021, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure generally relates to golf equipment, and more particularly to an iron-type golf club head having an insert.

Background Art

[0003] Cavity-back style game-improving irons have a cavity that is exposed across the entire rear of the iron. For aesthetics and vibration damping, it is common to include a badge within the rear cavity. However, current badges are typically rigid and are restricted by the rear wall such that they cannot be positioned across the entire rear surface and only contact a portion of the rear surface of the striking face. By covering only a portion of the striking face, the damping ability of the insert is limited. Further, finite element analysis has shown that the surrounding area and the rear wall of cavity-back irons tend to experience significantly greater vibrations than the rest of the golf club. Thus, there is a need in the art for a vibration damping insert that extends into the surrounding area of cavity-back irons while maintaining performance and facilitating assembly.

Brief Description of the Drawings

[0004] [Figure 1] FIG. 1 is a front view of a golf club head according to one embodiment.

[0005] [Figure 2] FIG. 2 is a rear view of the golf club head of FIG. 1.

[0006] [Figure 3] Figure 1 is a rear perspective view of the golf club head.

[0007] [Figure 4] Figure 1 is a cross-sectional view of a golf club head.

[0008] [Figure 5] Figure 1 shows the insert and the back view of the golf club head.

[0009] [Figure 6] This is a rear view of an insert according to one embodiment.

[0010] [Figure 7] Figure 6 is a cross-sectional view of a golf club head.

[0011] [Figure 8A] This is a rear view of an insert according to one embodiment.

[0012] [Figure 8B] This is a rear view of an insert according to one embodiment.

[0013] [Figure 8C] This is a rear view of an insert according to one embodiment.

[0014] [Figure 9] This is a cross-sectional view of a golf club head and insert according to one embodiment.

[0015] [Figure 10] This is a cross-sectional view of a golf club head and insert according to one embodiment.

[0016] [Figure 11] This is a rear view of an insert according to one embodiment.

[0017] [Figure 12] Rear view of an insert according to an embodiment.

[0018] [Figure 13] Rear view of an insert according to an embodiment.

[0019] [Figure 14] Rear view of an insert according to an embodiment.

[0020] [Figure 15] Rear view of an insert according to an embodiment.

[0021] [Figure 16A] Cross-sectional view of the insert of FIG. 14.

[0022] [Figure 16B] Cross-sectional view of the insert of FIG. 14.

[0023] [Figure 17] Rear view of an insert according to an embodiment.

[0024] [Figure 18] Rear view of an insert according to an embodiment.

[0025] [Figure 19A] Cross-sectional view of the insert of FIG. 18.

[0026] [Figure 19B] Cross-sectional view of the insert of FIG. 18.

[0027] [Figure 20] Rear view of a golf club head and an insert according to an embodiment.

[0028] [Figure 21] Rear view of the insert of FIG. 20.

[0029] [Figure 22] Figure 20 is a cross-sectional perspective view of a golf club head and insert.

[0030] [Figure 23] Figure 20 is a rear perspective view of the golf club head and insert.

[0031] [Figure 24] Figure 20 is a cross-sectional perspective view of a golf club head and insert.

[0032] [Figure 25] This is a rear view of a golf club head according to one embodiment.

[0033] [Figure 26] This is a top view of a golf club head and insert according to one embodiment.

[0034] [Figure 27] Figure 26 is a cross-sectional perspective view of a golf club head and insert.

[0035] [Figure 28] Figure 26 is a rear perspective view of the insert.

[0036] [Figure 29] This is a diagram showing a comparison club head.

[0037] [Figure 30] This is a bar graph showing the percentage change in MOI for six exemplary club heads and a control club head.

[0038] [Figure 31] This is a plot showing the CG height versus CG depth of six exemplary and comparison club heads.

[0039] [Figure 32] This is a bar graph showing the percentage change in MOI for two exemplary club heads and a control club head.

[0040] [Figure 33] This is a bar graph showing the CG height versus CG depth of two exemplary embodiments and a comparison of club heads.

[0041] [Figure 34] This is a bar graph showing the change in ball speed for two exemplary club heads and a control club head.

[0042] [Figure 35] This is a bar graph showing the change in ball speed for two exemplary club heads and a control club head.

[0043] [Figure 36] This is a bar graph showing the normalized ball speeds for two exemplary club heads and a control club head.

[0044] [Figure 37] This is a bar graph showing the change in spin rate for two exemplary club heads relative to a control club head.

[0045] [Figure 38] This is a bar graph showing the change in spin rate for two exemplary club heads relative to a control club head.

[0046] [Figure 39] This bar graph shows the change in launch angle for two exemplary club heads relative to a control club head.

[0047] [Figure 40] This is a bar graph showing the change in ball speed for two exemplary club heads and a control club head.

[0048] [Figure 41] This is a bar graph showing the change in ball velocity for two exemplary embodiments relative to a control club head.

[0049] [Figure 42] This is a bar graph showing the ball speed of two exemplary embodiments and a comparison club head.

[0050] [Figure 43] This is a bar graph showing the change in ball speed for two exemplary club heads relative to a control club head.

[0051] [Figure 44] This is a bar graph showing the ball speed for two exemplary club heads and a control club head.

[0052] [Figure 45] This is a bar graph showing the change in ball speed for two exemplary club heads relative to a control club head.

[0053] [Figure 46] This is a bar graph showing ball speeds for an exemplary club head and a control club head.

[0054] [Figure 47] This is a bar graph showing the spin rates of an exemplary club head and a control club head.

[0055] [Figure 48] This is a bar graph showing the launch angles of an exemplary club head and a comparison club head.

[0056] [Figure 49a] This diagram shows the frequencies of the control club heads.

[0057] [Figure 49b] This diagram shows the frequency of an example club head.

[0058] [Figure 50a] This is a bar graph showing ball speeds for an exemplary club head and a control club head.

[0059] [Figure 50b] This is a bar graph showing the launch angles of an exemplary club head and a comparison club head.

[0060] [Figure 50c] This is a bar graph showing the spin rates of an exemplary club head and a control club head.

[0061] [Figure 51a] This is a bar graph showing ball speeds for an exemplary club head and a control club head.

[0062] [Figure 51b] This is a bar graph showing the launch angles of an exemplary club head and a comparison club head.

[0063] [Figure 51c] This is a bar graph showing the spin rates of an exemplary club head and a control club head.

[0064] [Figure 52] This is a bar graph showing the results related to satisfaction after the test.

[0065] [Figure 53] This is a bar graph showing the results related to satisfaction after the test.

[0066] [Figure 54] This is a bar graph showing the results related to satisfaction after the test.

[0067] [Figure 55] This figure shows a golf club head according to one embodiment.

[0068] [Figure 56] This figure shows a golf club head according to one embodiment. [Modes for carrying out the invention]

[0069] This specification describes various embodiments of cavity-back iron-type golf club heads having inserts. Cavity-back iron-type club heads further include an undercut feature. The undercut feature may be an undercut formed by a perimeter wall, lip, rear body, or ledge. In most embodiments, the undercut feature is formed by the rear surface of the striking face and at least a portion of the rear wall around the club head. The undercut feature further accommodates the insert.

[0070] The insert covers the rear surface of the striking face and fills in most or all of the undercuts. The insert can also include variable density, varying from heel to toe and / or top to bottom. The insert can improve the perceived sound and feel while maintaining or improving various performance characteristics such as ball speed and spin.

[0071] The improvement in sound can be demonstrated by a reduction in the peak frequency during impact with the golf ball. Reducing the peak frequency decreases the volume at impact, resulting in a softer, more satisfying sound produced by the iron. To reduce the peak frequency, the insert can be placed within the most vibrating perimeter, such as the top rail, or within any other area where the insert can be press-fitted into an undercut.

[0072] Furthermore, inserts can have various features that optimize their mass properties, performance, and manufacturing process. For example, in many embodiments, inserts may have interconnected walls that define multiple voids, or empty spaces, to reduce the total mass of the insert. Thus, the voids can be positioned or created in such a way as to adjust the center of gravity of the entire club head or to adjust the stability behind the striking face. The interconnected walls and voids can improve the assembly process by making the insert more flexible, thereby allowing the insert to be easily press-fitted into cavities and undercuts.

[0073] In some embodiments, the insert is a single component that fills most or all of the cavity. In other embodiments, the insert may be made of multiple pieces. Dividing the insert into multiple pieces makes it easier to install the insert within the cavity and undercut.

[0074] In some embodiments, the insert may have an alignment mechanism that allows for increased precision in the placement of the insert. The alignment mechanism can fix the insert within the undercut, preventing any translational movement or sliding of the insert during use.

[0075] (definition) In the specification and claims, terms such as “first,” “second,” “third,” and “fourth” are used to distinguish similar elements, where present, and do not necessarily describe a specific sequential or temporal order. It should be understood that such terms are interchangeable under appropriate circumstances so that the embodiments described herein may operate in an order other than, for example, those illustrated herein or otherwise described herein. Furthermore, the terms “includes” and “having,” and all their variations, shall encompass non-exclusive inclusions in which a process, method, system, object, device, or apparatus containing a list of elements is not necessarily limited to those elements and may include other elements not expressly enumerated, or other elements specific to such process, method, system, object, device, or apparatus.

[0076] In this specification and in the claims, terms such as “left,” “right,” “front,” “rear,” “up,” “down,” “above,” and “downward,” where present, are used for illustrative purposes only and do not necessarily describe permanent relative positions. It should be understood that such terms are interchangeable under appropriate circumstances so that embodiments of the apparatus, methods, and / or articles described herein may operate in orientations other than those illustrated or otherwise described herein.

[0077] In many embodiments, the golf club head is a cavity-back iron club head. In these embodiments, the golf club head has a rear cavity. In other embodiments, the golf club head may be another type of iron club head, such as one with a perimeter undercut.

[0078] The iron-type golf club heads used herein refer to those with a degree of curvature lower than approximately 60 degrees, lower than approximately 59 degrees, lower than approximately 58 degrees, lower than approximately 57 degrees, lower than approximately 57 degrees, lower than approximately 56 degrees, lower than approximately 55 degrees, lower than approximately 54 degrees, lower than approximately 53 degrees, lower than approximately 52 degrees, lower than approximately 51 degrees, lower than approximately 50 degrees, lower than approximately 49 degrees, lower than approximately 48 degrees, lower than approximately 47 degrees, lower than approximately 46 degrees, lower than approximately 45 degrees, lower than approximately 44 degrees, lower than approximately 43 degrees, lower than approximately 42 degrees, and lower than approximately 41 degrees. It has a loft angle that is lower than approximately 40 degrees, lower than approximately 39 degrees, lower than approximately 38 degrees, lower than approximately 37 degrees, lower than approximately 36 degrees, lower than approximately 35 degrees, lower than approximately 34 degrees, lower than approximately 33 degrees, lower than approximately 32 degrees, lower than approximately 31 degrees, lower than approximately 30 degrees, lower than approximately 29 degrees, lower than approximately 28 degrees, lower than approximately 27 degrees, lower than approximately 26 degrees, lower than approximately 25 degrees, lower than approximately 24 degrees, lower than approximately 23 degrees, lower than approximately 22 degrees, lower than approximately 21 degrees, lower than approximately 20 degrees, lower than approximately 19 degrees, or lower than approximately 18 degrees.

[0079] Furthermore, in other embodiments, the loft angle of the iron-type club head 100 can be 60 degrees, 59 degrees, 58 degrees, 57 degrees, 56 degrees, 55 degrees, 54 degrees, 53 degrees, 52 degrees, 51 degrees, 50 degrees, 49 degrees, 48 ​​degrees, 47 degrees, 46 degrees, 45 degrees, 46 degrees, 45 degrees, 44 degrees, 43 degrees, 42 degrees, 41 degrees, 40 degrees, 39 degrees, 38 degrees, 37 degrees, 36 degrees, 35 degrees, 34 degrees, 33 degrees, 32 degrees, 31 degrees, 30 degrees, 29 degrees, 28 degrees, 27 degrees, 26 degrees, 25 degrees, 24 degrees, 23 degrees, 22 degrees, 21 degrees, 20 degrees, 19 degrees, 18 degrees, or 17 degrees.

[0080] For further examples, in other embodiments, the loft angle of an iron-type club head can range from 17 to 60 degrees. In other embodiments, the loft angle of the club head can range from 17 to 40 degrees, or from 40 to 60 degrees. In other embodiments, the loft angle of the club head can range from 17 to 35 degrees, 25 to 40 degrees, 30 to 45 degrees, 35 to 50 degrees, 40 to 55 degrees, or from 45 to 60 degrees. In other embodiments, the loft angle of the club head can range from 17 to 30 degrees, 30 to 40 degrees, 40 to 50 degrees, or from 50 to 60 degrees.

[0081] Other features and aspects will become apparent by considering the following detailed description and accompanying drawings. Before describing any embodiment of this disclosure in detail, it should be understood that the application of this disclosure is not limited to such details or embodiments, nor is it limited to the arrangement of components as described in the following description or illustrated in the drawings. This disclosure can correspond to other embodiments and can be practiced or implemented in various ways. It should be understood that the description of a particular embodiment is not intended to limit this disclosure in any way that does not encompass all modifications, equivalents, and substitutes that fall within the spirit and scope of this disclosure. It should also be understood that the expressions and terminology used herein are for illustrative purposes only and should not be considered limiting.

[0082] (1) Overview of the present invention This specification describes various embodiments of cavity-back iron-type golf club heads having inserts. In these embodiments, the iron-type golf club heads further include a rear cavity and a perimeter undercut. The insert extends into and fills most of the perimeter undercut.

[0083] An undercut can be formed in any area of ​​a golf club head, such as the toe, heel, top rail, sole, rear, or any combination thereof. An undercut can be a cavity, recess, ledge, or any other space that can accommodate an insert, or any combination of these features. In some embodiments, the undercut is formed by a rear wall extending backward from the periphery of the club head. In other embodiments, the undercut is formed by a recess within the rear of the club head. Furthermore, the undercut may be formed in only a portion of the periphery. For example, an undercut can be formed in 10% to 99% of the periphery of the club head. In some embodiments, the undercut is formed in 10% to 29%, 30% to 49%, 50% to 69%, 70% to 89%, or 90% to 99% of the periphery. In other embodiments, the undercut can extend across the entire periphery of the club head. For example, an undercut can be formed in 100% of the periphery.

[0084] In some embodiments, the insert comprises multiple voids. The voids allow for a reduction in the mass of the insert. This mass reduction can be positioned at any other location within the club head to improve the moment of inertia, center of gravity, or other mass properties. Furthermore, the voids allow for compression of the insert and press-fitting into undercuts or other mechanisms that can accommodate the insert.

[0085] In some embodiments, the insert further comprises multiple pieces. Two or more pieces can form the insert. Because the insert is divided into two or more pieces, each piece can be smaller and easier to insert into the undercut. The two or more pieces can be formed separately or integrally. The two or more pieces can contain different materials or be the same material. In other embodiments, the insert can be a single piece.

[0086] (2) General description of a golf club head Referring to the drawings, similar reference numerals are used in the drawings to identify similar or identical components in various drawings, and Figures 1 to 29 schematically illustrate iron-type club heads and inserts in various diagrams. Specifically, Figure 1 shows a club head 100 comprising a striking face 102, a hosel 116, a toe end 104, a heel end 106 opposite the toe end 104, a top rail 114, and a sole 108 opposite the top rail 114. As shown in Figure 2, the golf club head 100 further comprises a rear surface 118 opposite the striking face 102, a rear body 110, and a rear wall 112. The rear body 110 is formed around the rear surface such that a cavity 122 is defined by the rear body 110 and the rear surface 118. Referring to Figure 4, the club head 100 further comprises an undercut 124. The undercut 124 is formed by the rear body 110 and the rear surface 118.

[0087] (3) Inserts with voids Referring to Figures 5-7, the golf club head 100 further comprises an insert 120. The insert 120 is configured to abut the rear surface 118 and extend into most of the undercut 124. The insert 120 may further comprise multiple interconnected walls 126 defining multiple cavities 128. The insert 120 further comprises a rear surface 132 and a front surface 130. The rear surface 132 is exposed within the cavity 122 so as to be visible from the rear of the club. The front surface 130 abuts the rear surface 118 of the striking face 102. All of the cavities 128 are open toward the rear surface 132. Much or all of the cavities 128 extend through the insert and are open toward both the rear surface 132 and the front surface 130.

[0088] Multiple gaps 128 reduce the total mass of the insert, allowing discretionary mass to be placed at any other location on the club head 100. The gaps can remove any desired mass to optimize the overall mass characteristics of the club head, such as the location of the center of gravity and the moment of inertia. Multiple gaps can take on various shapes and sizes. For example, in some embodiments, the gaps 128 may have substantially similar sizes and shapes throughout the insert, as shown in Figure 6. In other embodiments, the gaps may have varying sizes throughout the insert. In some examples, the insert may have heel-biased gaps such that the gaps formed in the heel of the insert are larger than the gaps formed in the center and toe portions. Having larger gaps in the heel causes the entire center of gravity to shift towards the toe. Similarly, the insert may have toe-biased gaps such that the gaps formed in the toe of the insert are larger than the gaps formed in the center and heel portions. Having larger gaps in the toe of the insert causes the entire center of gravity to shift towards the heel. To optimize the overall mass characteristics of the club head, any size or location of the voids can be chosen. The voids can be formed and defined by interconnected walls.

[0089] The voids can also increase the flexibility of the insert by providing the insert with space to contract inward when force is applied. In some embodiments, the voids extend almost in the front-to-back direction to increase compressibility in the up-to-down direction. The voids allow the interconnected walls to contract into the empty space, reducing the overall size of the insert. When the pressure is released, the interconnected walls expand back to their original shape and structure. In other embodiments, the voids can twist and expand in multiple directions to increase compressibility in multiple directions. Increased compressibility improves ease of installation, a method that will be described in detail later.

[0090] Figures 8a and 8c show a club head 200 having a mechanism similar to that of club head 100. The club head further comprises various embodiments of inserts 220a, 220b, and 220c. Insert 220a comprises a plurality of gaps 226a having a heel bias such that the gap formed in the heel is larger than the gaps formed in the center and toe portions. Insert 220b comprises a plurality of gaps 226b having a center bias such that the gap is larger in the center than in the heel and toe portions. Insert 220c comprises a plurality of gaps having a toe bias such that the gap is larger than the gap at the center or heel position.

[0091] An insert has a total volume and a filling volume. The total volume is the volume occupied by the insert, more specifically, the volume bounded by the surface defined by the outermost points of the insert. The total volume may include empty space, i.e., voids. The total volume ranges from 0 cubic inches to 4 cubic inches (0 cm²). 3 ~65.55cm 3 ) can be. The total volume can cover 20% to 100% of the total cavity volume, including the undercut.

[0092] The filling volume is the volume occupied by the interconnected walls of the insert (i.e., excluding empty space). The filling volume can be approximately 5% to 90% of the total volume. In other words, the interconnected walls can occupy approximately 5% to 90% of the total volume. In some embodiments, the filling volume can be approximately 20% to 80%, 30% to 70%, 40% to 60%, 5% to 15%, 5% to 20%, 5% to 30%, 5% to 40%, 5% to 50%, or 45% to 75% of the total volume.

[0093] (4) Inserts with or without a top rail In some embodiments, a golf club head 200 having many of the above-described forms of the golf club head 100 may further include an insert 220 as described below. In this embodiment, the insert 220 includes a top rail portion extending into at least the upper portion of the undercut 224 of the club head 200. In this embodiment, the insert fills about 85% to 98% of the top rail undercut. For example, the insert may fill 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, or 98% of the top rail undercut. In some embodiments, the portion of the top rail insert is about 10% to 20% of the total volume of the insert. For example, the top rail portion of the insert accounts for 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20% of the total volume of the insert. Furthermore, since the insert has a solid top rail portion, there are no voids or empty spaces in the top rail portion.

[0094] In another embodiment, the golf club head 200 includes an insert 220. In this embodiment, the insert 220 does not have a top rail portion, and therefore does not extend into the upper portion of the undercut. In this embodiment, the insert 220 fills approximately 0% of the top rail undercut. The insert 220 may extend into other portions of the undercut, such as the heel portion, toe portion, or sole portion.

[0095] The inserts described herein may or may not have a top rail portion. The selection of a top rail portion, or the absence of a top rail portion, can be based on achieving desired mass characteristics, noise reduction, or manufacturability.

[0096] (5) Various structures of gaps and interconnected walls Referring to Figures 11-19 and as described above, the insert may have interconnected walls. The interconnected walls define a number of voids. The voids are empty spaces within the volume of the insert and between the interconnected walls. The voids may be asymmetrical or symmetrical. The voids may have a repeating pattern throughout the insert. Similarly, the interconnected walls may be asymmetrical or symmetrical. The interconnected walls may have a repeating pattern throughout. The interconnected walls may form a single continuous structure, thereby connecting all the interconnected walls to one another. The interconnected walls are made of solid material. The interconnected walls may be formed in any shape, size, pattern, or structure without departing from the present invention.

[0097] The interconnected walls form a variety of geometric structures, including but not limited to simple cubes, body-centered cubes, face-centered cubes, cylinders, multiple cylinders, diamonds, fluorite, octets, truncated cubes, truncated octahedra, Kelvin cells, isotrusses, gyroids, lattices, concave polygons, Weir-Phelans, triangular honeycombs, revolutionary triangular honeycombs, hexagonal honeycombs, concave polygonal honeycombs, revolutionary square honeycombs, square honeycombs, face-centered cubic foam, body-centered cubic foam, simple cubic foam, hexagonal prism diamonds, hexagonal prism edges, hexagonal prism vertex centroids, hexagonal prism central axis edges, hexagonal prism Rabes phases, trioctahedral vertex centroids, or octahedral vertex centroids.

[0098] The various structures used in the inserts and embodiments described later help achieve specified and unique mass properties by arranging the voids in various ways. Furthermore, different degrees of compressibility are possible depending on the structure. For example, an insert with a hexagonal structure will have higher compressibility in the vertical direction than an insert with a gyroid structure. The shape of the voids and the relative positions of the interconnected walls affect how the insert shrinks.

[0099] (6) Inserts with a hexagonal structure and top rail As shown in Figure 11, the insert 220 comprises interconnected walls 226 and a gap 228. In this embodiment, the gap is of uniform size. The gap 228 has a two-dimensional hexagonal shape. The gap 228 is an aperture that extends through the insert in a substantially front-to-back direction. In this embodiment, the gap 228 extends through the front and rear surfaces of the insert. The insert 220 further comprises a top rail portion that extends into the top rail undercut. The top rail insert portion accounts for approximately 10% to 20% of the total volume of the insert. For example, the top rail portion of the insert is 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20% of the total volume of the insert. Furthermore, since the insert comprises a solid top rail portion, there is no gap or empty space in the top rail portion.

[0100] (7) Inserts that have a hexagonal structure but do not have a top rail. Figure 12 shows an insert 250 similar to insert 220. Insert 250 comprises interconnected walls 256 and a gap 258. In this embodiment, the gap is of uniform size. The gap 256 has a hexagonal shape. The gap 258 is an aperture that extends through the insert in a substantially front-to-back direction. In this embodiment, the gap 258 extends through the front and rear surfaces of the insert. In this embodiment, insert 250 does not have a top rail portion.

[0101] (8) Inserts that have a grid structure but do not have a top rail. Figure 13 shows the insert 320. In this embodiment, the insert 320 comprises a plurality of interconnected walls 326 and a plurality of voids 328. The interconnected walls form a substantially grid structure, which forms a plurality of voids that take the overall shape of a three-dimensional hexagonal cell. In this embodiment, the voids 328 are arranged in an alternating repeating pattern. In this embodiment, the interconnected walls extend into the top rail portion. Furthermore, in this embodiment, the insert does not have a solid top rail portion.

[0102] (9) Inserts with a gyroid structure and top rail Figure 14 shows the insert 420. In this embodiment, the insert 420 comprises a plurality of interconnected walls 426 and a plurality of voids 428. The interconnected walls 426 have a gyroid structure. Because the interconnected walls 426 of the gyroid structure are nonlinear, the interconnected walls 426 twist / bend in three dimensions throughout the insert. Figures 16a and 16b further show the insert 420. Figure 19a shows a cross-section of the insert 420 at one location, and Figure 16b shows a cross-section of the insert 420 at a different location. Figures 16a and 16b show various cross-sectional shapes of the overall structure of the voids and interconnected walls. The voids 428 have a repeating pattern shape. In this embodiment, the insert 420 comprises a solid top rail portion. The top rail insert portion accounts for approximately 10% to 20% of the total volume of the insert. For example, the top rail portion of the insert accounts for 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20% of the total volume of the insert. Furthermore, since the insert has a solid top rail portion, there are no voids or empty spaces in the top rail portion.

[0103] (10) Inserts that have a gyroid structure but do not have a top rail. Figure 15 shows insert 450, which is similar to insert 420. Insert 450 comprises multiple interconnected walls 456 and multiple gaps 458. The interconnected walls 456 have a gyroid structure similar to that of insert 420. Insert 450 does not have a top rail portion.

[0104] (11) Inserts with a diamond structure and top rail Figure 17 shows insert 520. In this embodiment, insert 520 comprises a plurality of interconnected walls 526 and a plurality of voids 528. The interconnected walls 526 take the form of a diamond structure. Figures 19a and 19b further show insert 520. Figure 19a shows a cross-section of insert 520 at one location, and Figure 19b shows a cross-section of insert 520 at a different location. Figures 19a and 19b show various cross-sectional shapes of the overall structure of the voids and interconnected walls. The top rail insert portion accounts for approximately 10% to 20% of the total volume of the insert. For example, the top rail portion of the insert is 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20% of the total volume of the insert. Furthermore, since the insert has a solid top rail portion, there are no voids or empty spaces in the top rail portion.

[0105] (12) Multi-piece insert Referring to Figures 20 to 25, in some embodiments, the insert can consist of multiple pieces according to aspects of the present invention. The insert can consist of two, three, four, five, or more pieces. Each of the multiple pieces forms a part of the whole insert. The multiple pieces can be divided in any manner to make it easier to insert the insert into the cavity and undercut of the club head. The multiple pieces may be formed together before inserting the insert into the cavity, or each piece may be inserted into the cavity separately.

[0106] Referring to Figure 20, the multi-piece insert 620 is divided into an upper undercut gasket 620a, a central portion 620b, and a lower undercut gasket 620c. The upper and lower undercut gaskets 620a and 620b are configured to fit into the undercut portion of the rear body 610. In this embodiment, the upper undercut gasket 620a and the lower undercut gasket 620c are formed integrally with each other but are separate from the central portion 620b. In other embodiments, the upper undercut gasket and the lower undercut gasket are separate pieces and are not formed integrally. The central portion is configured to fit between the upper undercut gasket 620a and the lower undercut gasket 620c. When installed, the central portion 620b abuts against both the upper undercut gasket 620a and the lower undercut gasket 620c.

[0107] As shown in Figure 22, the central portion 620b comprises an adhesive layer 642 and a badge layer 644. The badge layer can improve the overall aesthetic appearance of the club head. The adhesive layer 642 provides a means for fixing the central portion 620b to the rear surface 618 of the club head. In some embodiments, the central portion can be flush with the rear body. In other embodiments, the central portion can be offset from the rear body.

[0108] In other embodiments, the insert may comprise two or more pieces. For example, the insert may comprise three, four, five, six, or more pieces. The pieces may be arranged in any manner according to embodiments of the present invention.

[0109] In the exemplary embodiment shown in Figure 25, the top rail section 620a is divided into six pieces. Each piece fills a portion of the top rail undercut. In this embodiment, the pieces are approximately the same size. In other embodiments, the pieces can be of any size. The pieces can range in width from approximately 0.25 inches to 0.75 inches (approximately 0.64 cm to 1.91 cm).

[0110] The upper undercut gasket may have a top surface and a bottom surface. The central portion has a top and a bottom. The lower undercut gasket may have a top surface and a bottom surface. As described above, the central portion is configured to abut against the upper and lower undercut gaskets, respectively. The top of the central portion abuts against the bottom surface of the upper undercut gasket. Furthermore, the bottom of the central portion abuts against the top surface of the lower undercut gasket. The central portion further secures the upper and lower undercut gaskets within the undercut.

[0111] The mass of the undercut piece can range from 0.2 grams to 10 grams. For example, the insert can range from 0.2 grams to 1 gram, 1 gram to 2 grams, 2 grams to 3 grams, 3 grams to 4 grams, 5 grams to 6 grams, 6 grams to 7 grams, 7 grams to 8 grams, 8 grams to 9 grams, or 9 grams to 10 grams. In some embodiments, the mass can be 0.2 grams, 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, 7 grams, 8 grams, 9 grams, or 10 grams.

[0112] The mass of the central portion can range from 0.2 grams to 10 grams. For example, the insert can range from 0.2 grams to 1 gram, 1 gram to 2 grams, 2 grams to 3 grams, 3 grams to 4 grams, 5 grams to 6 grams, 6 grams to 7 grams, 7 grams to 8 grams, 8 grams to 9 grams, or 9 grams to 10 grams. In some embodiments, the mass can be 0.2 grams, 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, 7 grams, 8 grams, 9 grams, or 10 grams.

[0113] In a preferred embodiment, the undercut gasket piece can be formed from a low-density material such as foam, plastic, or polymer. Furthermore, the undercut gasket piece can be made from a softer material that allows for elastic compression and expansion so that the undercut gasket piece can be compressed, inserted into the undercut, and then expanded to fill the undercut.

[0114] The upper and lower undercut gaskets can each create a seal that prevents water and debris from entering the undercut. As described above, the expansion of the undercut gasket when inserted into the undercut seals the undercut. Water and debris cannot enter the undercut, thus preventing unwanted rattling noises and vibrations.

[0115] The badge layer provides a layer of material that enhances the overall appearance of the club head to be aesthetically pleasing to the user. The badge layer conforms to the outline of the rear surface of the insert. In some embodiments, the badge layer is a single continuous layer covering the entire rear surface of the insert. In other embodiments, the badge layer covers a portion of the rear surface of the insert. The badge layer can be a single continuous piece or comprise several pieces to create any desired appearance. In some embodiments, the badge layer is composed of a thin metallic material such as aluminum. The metallic layer can be coated or colored to alter the appearance of the entire layer. In other embodiments, the badge layer can be composed of other materials, such as polymers, ceramics, or plastics.

[0116] The adhesive layer secures the central portion of the insert to the rear surface of the striking face. The adhesive layer can be formed from tape or liquid. The tape can be double-sided tape that adheres to both the rear surface of the striking face and the front surface of the central portion. Liquid adhesive can be applied to the rear surface of the striking face or the front surface of the central portion before inserting the central portion. The liquid adhesive then hardens, securing the central portion to the rear surface of the striking face. The adhesive layer can have a mass in the range of 0.1 to 3 grams. For example, the adhesive layer can be 0.1 grams, 0.75 grams, 1 gram, 1.5 grams, 2 grams, 2.5 grams, or 3 grams. Furthermore, to further secure the badge layer to the central portion, the adhesive layer can be applied between the badge layer and the central portion.

[0117] (13) Alignment mechanism In some embodiments, referring to Figures 26-28, a golf club head 700 having many aspects of the golf club head 100 described above may further include an alignment mechanism 762 as described later. The golf club head 700 may comprise one of the inserts 120, 220, 320, 420, 520, and 620 described above. The alignment mechanism can enable more precise placement of the insert within the undercut. Furthermore, the alignment mechanism fixes the insert within the cavity and undercut, preventing any sliding or translation of the insert during use. In the embodiments shown in Figures 26-28, the alignment mechanism is in the form of an aperture in the top rail portion of the club head 700. In other embodiments, the alignment mechanism may be a through hole, rib, projection, or any other well-known geometric shape. In these and other embodiments, the alignment mechanism may be located in any part of the club head that contacts the insert. The insert may further comprise a geometric shape complementary to the alignment mechanism.

[0118] Figure 26 shows a golf club head 700 equipped with a top rail alignment mechanism 740. In this embodiment, the top rail alignment mechanism 740 is a plurality of circular apertures extending through the top rail. In this embodiment, there are five circular apertures having varying sizes.

[0119] Figures 27 and 28 further show the insert 720. The insert 720 comprises a multi-piece structure according to an embodiment of the present invention. The insert 720 comprises an upper undercut gasket 720a, a central portion 720b, and a lower undercut gasket 720c. The upper undercut gasket 720a further comprises a top rail projection configured to fill the top rail alignment mechanism 740. As described above, the alignment mechanism allows for the precise placement of the undercut gasket within the undercut. Furthermore, the alignment mechanism provides a visual aid for the user to align the ball when addressing it.

[0120] Any combination of the features described herein can be used in an insert to improve sound and feel while maintaining performance.

[0121] (14) Material In some embodiments, the faceplate may comprise a faceplate material of a first density. The body may comprise a body material of a second density. The insert may comprise an insert material of a third density. The third density may be lower than the first density and / or the second density. In some embodiments, the faceplate may be the same material (and thus the same density) as the body. In some embodiments, the insert may comprise two or more materials, the materials having different densities and being different from or the same as the material of the faceplate and / or body.

[0122] The body may comprise a body material such as steel, alloy steel, or any other suitable material. The body material may comprise a material selected from the group consisting of steel-based materials or alloy steels. In some embodiments, the body material may be 8620 carbon steel containing iron, as well as about 0.17–0.23 wt% carbon, 0.15–0.35 wt% silicon, 0.60–0.90 wt% manganese, 0.15–0.30 wt% molybdenum, 0.40–0.70 wt% nickel, 0.40–0.65 wt% chromium, 0.040 wt% phosphorus, and trace amounts of other elements. In some embodiments, the body material may be 300 grade steel containing iron, as well as about 18–19 wt% nickel, 8.5–9.5 wt% cobalt, 4.6–5.2 wt% molybdenum, 0.5–0.8 wt% titanium, 0.05–0.15 wt% aluminum, and trace amounts of other elements. In some embodiments, the body material may be maraging steel containing iron, as well as about 17–19 wt% nickel, 8–12.5 wt% cobalt, 3.0–5.2 wt% molybdenum, 0.15–1.6 wt% titanium, 0.05–0.15 wt% aluminum, and trace amounts of other elements. The density of the body material may range from 7.70 to 8.10 grams per cubic centimeter (hereinafter, "g / cc"). In some embodiments, the density of the main material can be 7.70 g / cc, 7.75 g / cc, 7.80 g / cc, 7.85 g / cc, 7.90 g / cc, 7.95 g / cc, 8.05 g / cc, or 8.10 g / cc. In one embodiment, the density of the main material is 7.85 g / cc.

[0123] The insert may include insert materials such as polymer matrix composites. The polymer matrix composite may include glass-filled elastomers, stainless steel-filled elastomers, tungsten-filled elastomers, thermoplastic polyurethane (TPU) composites, thermoplastic elastomer (TPE) composites, or any other elastomer matrix composites, Kevlar® (aramid) fiber-reinforced polymers, carbon fiber-reinforced polymers, rubber, ethylene vinyl acetate foams, polymer foams, any combination of suitable resins and suitable reinforcing fibers, or any combination of the above materials.

[0124] The density of the insert can be in the range of 1.0 to 12.0 g / cc. The density of the insert can be in the range of 1.0 g / cc to 5.0 g / cc. In some embodiments, the density of the insert can be 1.0 g / cc, 1.5 g / cc, 2.0 g / cc, 2.5 g / cc, 3.0 g / cc, 3.5 g / cc, 4.0 g / cc, 4.5 g / cc, or 5.0 g / cc. When the density of the insert is low, the central part of the club head housing the insert is lighter, allowing the weight to be redistributed around the perimeter of the club head. This redistributed weight increases the forgiveness of the club head.

[0125] The durometer of the insert can range from 20A to 90A on the Shore A hardness scale. In some embodiments, the durometer is 20A, 25A, 30A, 35A, 40A, 45A, 50A, 55A, 60A, 65A, 70A, 75A, 80A, 85A, or 90A. The lower durometer characterizes the softer material. Softer materials are preferable to allow for the compressibility of the insert placed within the undercut. Furthermore, softer materials have better vibration damping capabilities than harder materials.

[0126] The faceplate material can be a steel-based material, a titanium-based material, a titanium alloy, or any combination thereof. The steel-based material can be carbon steel, 17-4PH stainless steel, 431, 455, 475, C300, maraging steel, or other types of stainless steel. The titanium alloy can be Ti-7S+(ST721), Ti-9S, Ti-6-4, Ti-15-3-3-3, or any other suitable titanium alloy. The titanium alloy may also be an α-β titanium alloy. In embodiments where the faceplate is a titanium-based material, an aluminum alloy, a titanium alloy, or any combination thereof, the density of the faceplate material can be in the range of 2.6 to 8.7 g / cc. In some embodiments, the density of the faceplate material can be 2.6 g / cc, 2.8 g / cc, 3.0 g / cc, 3.2 g / cc, 3.4 g / cc, 3.6 g / cc, 3.8 g / cc, 4.0 g / cc, 4.2 g / cc, 4.4 g / cc, 4.6 g / cc, 4.8 g / cc, 5.0 g / cc, 5.2 g / cc, 5.4 g / cc, 5.6 g / cc, 5.8 g / cc, 6.0 g / cc, 6.2 g / cc, 6.4 g / cc, 6.6 g / cc, 6.8 g / cc, 7.0 g / cc, 7.2 g / cc, 7.4 g / cc, 7.6 g / cc, 7.8 g / cc, 8.0 g / cc, 8.2 g / cc, 8.4 g / cc, 8.6 g / cc, or 8.7 g / cc. In embodiments where the faceplate is made of a steel-based material, the density of the faceplate material can be in the range of 7.7 g / cc to 8.1 g / cc.

[0127] (15) Manufacturing method To form the first and second embodiments, the golf club head body can be cast from a metal material such as stainless steel. The body can be cast to have a front opening for receiving the face plate. The face plate can be cast or forged. The face plate can be machined to include grooves or other face texture mechanisms as needed. The insert can be manufactured by injection molding from a thermoplastic composite material (hereinafter, "TPC") or through additive manufacturing. The insert can then be placed in the body by sliding it into the cavity through the front opening. In some embodiments, the insert can be secured in the cavity using adhesive. In some embodiments, ultra-high density tape can be used to further secure the insert in the cavity and prevent rattling. After the insert is placed in the cavity, the face plate can be placed in the front opening and swaged (also called "swaging") onto the body. The face plate cannot be welded onto the body because the heat from welding would melt the insert. However, the swaging process does not require high heat and can therefore be carried out without damaging the insert.

[0128] To form the third embodiment, the golf club head body is cast so that the face of the golf club head is included at the front. The golf club head body is cast from a metal material such as stainless steel. The face of the body can be machined to include grooves or other face texture mechanisms as needed. The body can be cast to have a toe opening for receiving an insert. The insert can be formed in a manner similar to the means used for the first and second embodiments. The insert can be shaped to have an outline that allows it to slide into the cavity through the toe opening of the body. The insert can be fixed and bonded in the cavity by adhesive. In some embodiments, ultra-high density tape can be used to further fix the insert in the cavity and prevent rattling. The golf club head can be polished, painted and finished as needed.

[0129] Because the rules of golf are subject to change from time to time (for example, new rules may be adopted or old rules may be eliminated or modified by the Golf Standardization Body and / or governing body), the golf equipment relating to the methods, apparatus, and / or products described herein may or may not conform to the rules of golf at any particular time. Accordingly, the golf equipment relating to the methods, apparatus, and / or products described herein may be advertised, marketed, and / or sold as golf equipment that conforms or does not conform to the rules. The methods, apparatus, and / or products described herein are not limited in this respect.

[0130] Although a specific order of actions has been described above, these actions may be performed in other time sequences. For example, two or more of the actions described above may be performed sequentially, in parallel, or simultaneously. Alternatively, two or more actions may be performed in reverse order. Furthermore, one or more of the actions described above may not be performed at all. The apparatus, methods, and products described herein are not limited in this respect.

[0131] While the present invention has been described in relation to various embodiments, it will be understood that the present invention is subject to further modifications. This application seeks to encompass any variations, uses, or adaptations of the present invention that generally follow the principles of the present invention and include such deviations from the disclosure as being within the scope of practice known in the art to which the invention relates.

[0132] (Examples) [Table 1]

[0133] The embodiments detailed below compare several exemplary club head combinations described in Table 1 above.

[0134] I. Comparison of club heads with inserts having or not having top rail filling, as described herein, with a control club head having a solid, partially filled insert. Example I shows comparative results relating CG position and MOI between six exemplary embodiments of the present invention and a control club head. Described herein are the first exemplary golf club head, the second exemplary golf club head, the third exemplary golf club head, the fourth exemplary golf club head, and the fifth exemplary golf club head, each having similar dimensions (length, width, height, depth, etc.) to the golf club head 100.

[0135] The first, second, third, fourth, fifth, and sixth exemplary club heads each have a volume, mass, crown thickness, face thickness, and body structure similar to club head 100. Both the first and second exemplary club heads have an insert having a hexagonal structure, as described above for club head 200 and shown in Figure 6. The first exemplary club head has a first insert having a hexagonal structure without a top rail filling portion. The second exemplary club head has a second insert having a hexagonal structure with a top rail filling portion.

[0136] Similarly, both the third and fourth exemplary embodiments include an insert having the gyroid structure described above in the club head 400. The third exemplary embodiment includes a third insert without a top rail filling, while the fourth exemplary embodiment includes a fourth insert with a top rail filling.

[0137] Similarly, both the fifth and sixth exemplary embodiments feature an insert having the diamond structure described above in the club head 500. The insert of the fifth exemplary embodiment is a fifth insert without a top rail filling, while the sixth exemplary embodiment features a sixth insert with a top rail filling. The contrasting club head features a solid insert that does not extend to the perimeter undercut, as shown in Figure 29.

[0138] The first, second, third, fourth, fifth, and sixth exemplary club heads, as described above, were compared to a control club head shown in Figure 29, which has similar volume, mass, crown thickness, face thickness, and body structure to club head 100. The control club head has the same body structure as both the first and second exemplary clubs, and a third insert that differs from the first and second inserts. The third insert is a combination of solid materials and does not contain an aperture. The third insert fills only a portion of the cavity and does not fill any portion of the undercut.

[0139] Referring to Figure 30, the first, second, third, fourth, fifth, and sixth exemplary club heads each had a lower MOI than the control club head. The first exemplary club head showed the smallest change compared to the control club head, with an MOI reduction of approximately 1.7 g × in². The second, third, fourth, fifth, and sixth exemplary embodiments all showed nearly the same MOI reduction as the control club head, with reductions ranging from 4.5 g × in² to 4.8 g × in².

[0140] Referring to Figure 31, the first, second, third, fourth, fifth, and sixth exemplary club heads each had a lower CG height (CGy) than the control club head. The first, third, fourth, fifth, and sixth exemplary club heads had a greater CG depth (CGz) than the control club head. The first exemplary club head showed the smallest change compared to the control club head, with an MOI reduction of approximately 1.7 g × in². The second, third, fourth, fifth, and sixth exemplary embodiments all showed approximately the same MOI reduction as the control club head, with reductions ranging from 4.5 g × in² to 4.8 g × in².

[0141] II. Comparison of a club head with a variable density insert as described herein with a control club head with a solid, partially filled insert. Example II presents the results of a comparison between the seventh exemplary club head, the eighth exemplary club head, and a control club head. Referring to Table 1, the club heads compared in this example are exemplary club head 7, exemplary club head 8, and the control club head. The seventh exemplary club head features a hexagonal insert with a heel-biased gap, as shown in Figure 8a, and is described in Table 1 as exemplary club head 7. The eighth exemplary club head features a hexagonal insert with a toe-biased gap, as shown in Figure 8c, and is described in Table 1 as exemplary club head 8. Exemplary club heads 1, 2, 3, 4, 5, and 6 are not considered in this example. Exemplary club heads 7 and 8 have similar dimensions (length, width, height, depth, etc.), volume, mass, crown thickness, face thickness, and body structure to golf club head 100.

[0142] The seventh and eighth exemplary club heads were compared to a control club head shown in Figure 29, which had similar volume, mass, crown thickness, face thickness, and body structure to club head 100. The control club head had the same body structure as the exemplary club and a control insert different from the first insert. The control insert was a combination of solid materials and did not contain an aperture. The control insert filled only a portion of the cavity and did not fill any portion of the undercut.

[0143] As shown in Figure 32, both the seventh and eighth exemplary club heads exhibit a reduced MOI compared to the control club head. The eighth exemplary club head showed a slightly greater reduction in MOI than the seventh exemplary club head.

[0144] As shown in Figure 33, both the seventh and eighth exemplary club heads had a lower center of gravity (indicated by CGy) compared to the control club head. The eighth exemplary club head had a slightly lower center of gravity than the seventh exemplary club head.

[0145] Furthermore, both the seventh and eighth exemplary club heads had their center of gravity (indicated by CGz) shifted further back than the control club head. The seventh exemplary club head had its center of gravity shifted even slightly further back than the eighth exemplary club head.

[0146] III. Comparison of the club head described herein with a control club head having a solid, partially filled insert. Example II presents the results of a comparison between the seventh exemplary club head, the eighth exemplary club head, and a control club head. Referring to Table 1, the club heads compared in this example are exemplary club head 7, exemplary club head 8, and the control club head. The seventh exemplary club head features a hexagonal insert with a heel-biased gap, as shown in Figure 8a, and is described in Table 1 as exemplary club head 7. The eighth exemplary club head features a hexagonal insert with a toe-biased gap, as shown in Figure 8c, and is described in Table 1 as exemplary club head 8. Exemplary club heads 1, 2, 3, 4, 5, and 6 are not considered in this example. Exemplary club heads 7 and 8 have similar dimensions (length, width, height, depth, etc.), volume, mass, crown thickness, face thickness, and body structure to golf club head 100.

[0147] The seventh and eighth exemplary club heads were compared to a control club head shown in Figure 29, which had similar volume, mass, crown thickness, face thickness, and body structure to club head 100. The control club head had the same body structure as the exemplary club head and a control insert that was different from the first insert. The control insert was a combination of solid materials and did not contain an aperture. The control insert filled only a portion of the cavity and did not fill any portion of the undercut.

[0148] The same number of hits were performed for each of the seventh and eighth exemplary club heads. Referring to Figure 30, for each club head, hits were performed at 11 different impact positions on the clubface. Specifically, data was recorded at the center impact position 170, five toe impact positions (171, 172, 173, 174, 175), and five heel impact positions (165, 166, 167, 168, 169), with the toe and heel impact positions gradually moving closer to the toe or heel, respectively. For each hit, data on ball speed, spin rate, and launch angle were collected. Impact positions heel 5 (165) and toe 5 (175) are the heel impact positions furthest from the center, while heel 4 (166) and toe 4 (174) are the heel impact positions second furthest from the center.

[0149] Figure 34 shows the ball velocities of both the seventh and eighth exemplary club heads at each of the eleven impact positions relative to the control club head. Referring to Figure 34, both the seventh and eighth exemplary club heads had faster ball velocities than the control club head at each of the eleven impact positions.

[0150] On average, the seventh exemplary club head showed an increase in ball speed of 0.1–1.5 mph (0.16–2.41 km / h) compared to the control club head. This increase in ball speed could lead to an increase in travel distance of up to approximately 3 yards (2.74 m). On average, the eighth exemplary club head showed an increase in ball speed of 0.2–1.2 mph (0.32–1.93 km / h) compared to the control club head. This increase in ball speed could lead to an increase in travel distance of up to approximately 2 yards (1.83 m).

[0151] Figure 35 shows the same data as Figure 34, but is organized to show the differences in ball velocity during heel, center, and toe strikes between the seventh exemplary club head, the eighth exemplary club head, and the control club head. These differences will be discussed in detail below.

[0152] Referring to Figure 35, on average, the seventh exemplary club head showed an increase in ball velocity of over 1 mph (1.61 km / h) for heel-side impacts of the striking face (at all impact positions: heel 1, heel 2, heel 3, heel 4, and heel 5) compared to impacts at the same positions of the control club head. On average, the eighth exemplary club head showed an increase in ball velocity of approximately 1 mph (1.61 km / h) for heel-side impacts of the striking face (at all impact positions: heel 1, heel 2, heel 3, heel 4, and heel 5) compared to impacts at the same positions of the control club head.

[0153] Referring again to Figure 35, on average, the seventh exemplary club head showed an increase in ball speed of approximately 0.75 mph (1.21 km / h) for a center strike on the face compared to a strike at the same position on the control club head. On average, the eighth exemplary club head showed an increase in ball speed of approximately 0.15 mph (0.24 km / h) for a center strike on the face compared to a strike at the same position on the control club head.

[0154] Referring again to Figure 35, on average, the seventh exemplary club head showed an increase in ball velocity of approximately 0.5 mph (0.80 km / h) for toe-side impacts of the striking face (at all impact positions of toe 1, toe 2, toe 3, toe 4, and toe 5) compared to impacts at the same positions of the control club head. Referring again to Figure 35, on average, the eighth exemplary club head showed an increase in ball velocity of approximately 0.3 mph (0.48 km / h) for toe-side impacts of the striking face (at all impact positions of toe 1, toe 2, toe 3, toe 4, and toe 5) compared to impacts at the same positions of the control club head.

[0155] Overall, the seventh and eighth exemplary club heads demonstrated increased ball velocity compared to the control club head at any point of impact on the club head. The most significant improvements in ball velocity for the seventh and eighth exemplary club heads were observed at impact on the heel side of the striking face. These increases in ball velocity can lead to an increase in travel distance of up to approximately 3 yards (2.74 m).

[0156] Figure 36 shows the same data as Figure 34. However, in Figure 36, the data for the seventh exemplary club head, the eighth exemplary club head, and the control club head have been separately normalized so that, although there is variation in values ​​among the three club heads, the ball velocity at "center" impact is depicted as 1.

[0157] Referring to Figure 36, the seventh exemplary club head demonstrates reduced variation in ball velocity between strikes at all different impact positions on the striking face. As can be seen in Table 7, for all three club heads, ball velocity decreases to some extent gradually from the center toward impact position heel 5 and from the center toward impact position toe 5. The ball velocity of the seventh exemplary club head decreases only slightly from the center impact position toward heel 5 and toe 5, respectively. This means that the seventh exemplary club head maintains ball velocity better than the control club head for off-center strikes.

[0158] The eighth exemplary club head shows reduced ball velocity variation between impacts at all positions toward impact position heel 5 compared to the control club head. For the five heel-side impact positions, the ball velocity drop of the eighth exemplary club head is less than that of the control club head.

[0159] The seventh exemplary club head, compared to both the second exemplary club head and the control club head, showed a more gradual decrease in ball velocity across all impact positions, both on the toe and heel sides of the striking face. As mentioned above, the eighth exemplary club head showed reduced ball velocity variability on the heel side of the striking face compared to the control club head, while the seventh exemplary club head showed even less variability. Thus, both the seventh and eighth exemplary club heads showed improvement over the control club head in ball velocity variability for off-center impacts. The seventh exemplary club head had the most consistent ball velocity across the entire striking face.

[0160] Figure 37 shows the spin rates of both the seventh and eighth exemplary club heads at each of the eleven impact positions relative to the control club head. Referring to Table 8, the seventh exemplary club head had a higher spin rate than the control club head at each of the eleven impact positions. The eighth exemplary club head had a higher spin rate than the control club head at 10 of the eleven impact positions.

[0161] On average, both the seventh and eighth exemplary club heads showed increased spin compared to the control club head. Increased spin can prevent the ball from traveling a longer distance from its landing position.

[0162] Figure 38 shows the same data as Figure 37, but is organized to show the differences in spin rates for heel, center, and toe strikes between the seventh exemplary club head, the eighth exemplary club head, and the control club head. These differences will be discussed in detail below.

[0163] Referring to Figure 38, on average, the seventh exemplary club head showed an increase in spin of approximately 125 rpm for heel-side impacts of the striking face (at all impact positions: heel 1, heel 2, heel 3, heel 4, and heel 5) compared to impacts at the same positions on the control club head. On average, the eighth exemplary club head showed an increase in spin of approximately 95 rpm for heel-side impacts of the striking face (at all impact positions: heel 1, heel 2, heel 3, heel 4, and heel 5) compared to impacts at the same positions on the control club head.

[0164] Referring again to Figure 38, on average, the seventh exemplary club head showed an increase in spin of approximately 20 rpm for a center strike on the face compared to a control club head at the same position. On average, the eighth exemplary club head showed an increase in spin of approximately 245 rpm for a center strike on the face compared to a control club head at the same position.

[0165] Referring again to Figure 38, on average, the seventh exemplary club head showed an increase in spin of approximately 165 rpm for toe-side impacts of the striking face (at all impact positions of toe 1, toe 2, toe 3, toe 4, and toe 5) compared to impacts at the same positions of the control club head. On average, the eighth exemplary club head showed an increase in spin of approximately 125 rpm for toe-side impacts of the striking face (at all impact positions of toe 1, toe 2, toe 3, toe 4, and toe 5) compared to impacts at the same positions of the control club head.

[0166] Overall, the seventh and eighth exemplary club heads showed increased spin rates compared to the control club heads for impacts on the heel, toe, or center of the striking face. The most significant improvements in spin rates were observed in the center of the striking face for the eighth exemplary club head and on the toe for the seventh exemplary club head.

[0167] Figure 39 shows the launch angles of both the seventh and eighth exemplary club heads at each of the eleven impact positions relative to a control club head. Referring to Figure 39, the seventh exemplary club head has a lower launch angle than the control club head at all eleven impact positions. The eighth exemplary club head had a lower launch angle at 10 of the eleven impact positions. Furthermore, the seventh exemplary club head has a lower launch angle than the eighth exemplary club head at 10 of the eleven impact positions.

[0168] Figure 40 shows the same data as Figure 39, but is organized to show the differences in launch angles for heel, center, and toe strikes between the seventh exemplary club head, the eighth exemplary club head, and the control club head. These differences will be discussed in detail below.

[0169] Referring to Figure 40, on average, the seventh exemplary club head showed a launch angle reduction of approximately 0.35 degrees for heel-side impacts of the striking face (at all impact positions: heel 1, heel 2, heel 3, heel 4, and heel 5) compared to impacts at the same positions on the control club head. On average, the eighth exemplary club head showed a launch angle reduction of approximately 0.17 rpm for heel-side impacts of the striking face (at all impact positions: heel 1, heel 2, heel 3, heel 4, and heel 5) compared to impacts at the same positions on the control club head.

[0170] Referring again to Figure 40, on average, the seventh exemplary club head showed a launch angle reduction of approximately 0.47 degrees for a center strike on the striking face compared to a strike at the same position on the control club head. On average, the eighth exemplary club head showed a launch angle reduction of approximately 0.2 degrees for a center strike on the striking face compared to a strike at the same position on the control club head.

[0171] Referring again to Figure 40, on average, the seventh exemplary club head showed a launch angle reduction of approximately 0.3 degrees for toe-side impacts of the striking face (at all impact positions of toe 1, toe 2, toe 3, toe 4, and toe 5) compared to impacts at the same positions of the control club head. On average, the eighth exemplary club head showed a launch angle reduction of approximately 0.17 degrees for toe-side impacts of the striking face (at all impact positions of toe 1, toe 2, toe 3, toe 4, and toe 5) compared to impacts at the same positions of the control club head.

[0172] Overall, both the seventh and eighth exemplary club heads showed a slight decrease in launch angle compared to the control club head. The variation in launch angle was less than 0.5 degrees at all impact positions. Since these differences in launch angle are small and not statistically significant, it can be concluded that the launch angles of the seventh and eighth exemplary club heads are very similar to those of the control club head.

[0173] IV. Comparison of club heads with and without top rails, gyro-twist, hexagonal, and diamond designs, as described herein, with control club heads. Example IV shows the results of a comparison between the first exemplary club head, the second exemplary club head, the third exemplary club head, the fourth exemplary club head, the fifth exemplary club head, the sixth exemplary club head, and the control club head. Referring to Table 1, the club heads compared in this example are exemplary club head 1, exemplary club head 2, and the control club head, exemplary club head 3, exemplary club head 4, and the control club head, and exemplary club head 5, exemplary club head 6, and the control club head. Each of the exemplary club heads 1, 2, 3, 4, 5, and 6 has similar dimensions (length, width, height, depth, etc.) to golf club head 100.

[0174] Exemplary club heads 1, 2, 3, 4, 5, and 6 have similar volume, mass, crown thickness, face thickness, and body structure to golf club head 100. The first and second exemplary club heads are described in Table 1 as exemplary club head 1 and exemplary club head 2, respectively. Both have an insert having a hexagonal structure, as described above for club head 200. The first exemplary club head has a first insert having a hexagonal structure without a top rail filling portion. The second exemplary club head has a second insert having a hexagonal structure with a top rail filling portion.

[0175] Similarly, the third and fourth exemplary club heads are described in Table 1 as exemplary club head 3 and exemplary club head 4, respectively. Both the third and fourth exemplary club heads include an insert having the gyroid structure described above in club head 400. The third exemplary embodiment includes a third insert without a top rail filling, while the fourth exemplary embodiment includes a fourth insert with a top rail filling.

[0176] Similarly, the fifth and sixth exemplary club heads are described in Table 1 as exemplary club head 5 and exemplary club head 6, respectively. Both the fifth and sixth exemplary club heads feature an insert having the diamond structure described above in club head 500. The insert of the fifth exemplary club head is a fifth insert without a top rail filling, while the sixth exemplary club head is a sixth insert with a top rail filling.

[0177] The first, second, third, fourth, fifth, and sixth exemplary club heads, as described above, were compared to a control club head shown in Figure 29, which has similar volume, mass, crown thickness, face thickness, and body structure to club head 100. The control club head has the same body structure as both the first and second exemplary clubs, and a third insert that differs from the first and second inserts. The third insert is a combination of solid materials and does not contain an aperture. The third insert fills only a portion of the cavity and does not fill any portion of the undercut.

[0178] Each of the 1st, 2nd, 3rd, 4th, 5th, and 6th exemplary club heads, as well as the control club head, was struck the same number of times at nine impact positions. The impact positions can be seen in Figure 57. The 1st impact position is the toe region 176. The 2nd impact position is the low toe region 177. The 3rd impact position is the high toe region 178. The 4th impact position is the low center region 179. The 5th impact position is the center region 170. The 6th impact position is the high center region 180. The 7th impact position is the low heel region 181. The 8th impact position is the high heel region 182. The 9th impact position is the heel region 183. Ball velocity data was collected for the ball struck at each impact position and recorded in the tables in Figures 41 to 46.

[0179] Referring to Figures 41 and 42, the second exemplary club head showed a faster ball velocity than the control club head at 6 out of 9 impact positions. On average, the second exemplary club head showed an increase in ball velocity compared to the control club head. The first exemplary club head showed a faster ball velocity than the control club head at only 3 out of 9 impact positions. This data indicates that the ball velocities of both the first and second exemplary club heads were similar to those of the control club head.

[0180] Referring to Figures 43 and 44, the fourth exemplary club head showed faster ball velocities than the control club head at 6 of the 9 impact positions. The third exemplary club head showed faster ball velocities than the control club head at 7 of the 9 impact positions. On average, both the third and fourth exemplary club heads showed an increase in ball velocities compared to the control club head. This data indicates that the ball velocities of both the first and second exemplary club heads were similar to, or slightly faster than, the ball velocities of the control club head.

[0181] Referring to Figures 45 and 46, the sixth exemplary club head showed a faster ball velocity than the control club head at three of the nine impact positions. The fifth exemplary club head showed a faster ball velocity than the control club head at only one of the nine impact positions. This data indicates that the ball velocities of both the first and second exemplary club heads were similar to those of the control club head.

[0182] V. Comparison of a club head with a flexible heel as described herein with a control club head. Example V shows the results of a comparison between the seventh exemplary club head and a control club head. Referring to Table 1, the club heads compared in this example are exemplary club head 7 and a control club head. The seventh exemplary club head, as shown in Figure 8a, has a hexagonal insert with a heel bias gap and is described in Table 1 as exemplary club head 7. Exemplary club heads 1, 2, 3, 4, 5, and 6 are not considered in this example. Exemplary club head 7 has similar dimensions (length, width, height, depth, etc.), volume, mass, crown thickness, face thickness, and body structure to golf club head 100.

[0183] A seventh exemplary club head was compared to a control club head shown in Figure 29, which has similar volume, mass, crown thickness, face thickness, and body structure to club head 100. The control club head has the same body structure as the exemplary club and a control insert that is different from the first insert. The control insert is a combination of solid materials and does not contain an aperture. The control insert fills only a portion of the cavity and does not fill any portion of the undercut.

[0184] The same number of hits were performed for each of the seven exemplary and control golf clubs. Environmental factors were similar for each hit, and factors such as swing speed and impact position were kept nearly identical. Ball speed, spin rate, and launch angle were recorded.

[0185] Referring to Figure 47, the average ball speed of the seventh exemplary club head is faster than the average ball speed of the control club head. Specifically, the average ball speed of the seventh exemplary club head was 0.8 mph (1.29 km / h) faster than that of the control club head. This increase in ball speed can result in an approximate increase in distance traveled of about 2 yards (1.83 m).

[0186] Referring to Figure 48, the average spin rate of the seventh exemplary club head is greater than that of the control club head. Specifically, the average spin rate of the exemplary club head was 83 rpm greater than that of the control club head. Increased spin rate can be desirable, as it can help prevent the ball from rolling a greater distance from where it lands.

[0187] Referring to Figure 49, the average launch angle of the seventh exemplary club head is similar to, and slightly lower than, the average launch angle of the control club head. Specifically, the average launch angle of the seventh exemplary club head was 0.3 degrees lower than that of the control club head. This slight reduction in launch angle can result in increased face flex. The increase in ball speed provided by the seventh exemplary golf club head, as described above, overcomes and transcends any potential drawbacks resulting from the slight reduction in launch angle mentioned.

[0188] Overall, the seventh exemplary club head exhibits increased ball speed, increased spin, and a slight decrease in launch angle compared to the control club head. The increased ball speed and launch angle provide golfers with improved performance, which can lead to longer ball travel distances and improved ability for the ball to stay near the landing point without rolling further. This data indicates that the seventh exemplary club head exhibits similar performance characteristics to the control club head.

[0189] VI. Comparison of a club head with flexible heel and top rail fillings as described herein with a control club head. Example VI presents the results of a comparison between the seventh exemplary club head and the control club head, which are the same two club heads compared in Example V. Referring to Table 1, the club heads compared in this example are exemplary club head 7 and the control club head. The seventh exemplary club head, as shown in Figure 8a, has a hexagonal insert with a heel bias gap and is described in Table 1 as exemplary club head 7. Exemplary club heads 1, 2, 3, 4, 5, and 6 are not considered in this example. Exemplary club head 7 has similar dimensions (length, width, height, depth, etc.), volume, mass, crown thickness, face thickness, and body structure to golf club head 100.

[0190] A seventh exemplary club head was compared to a control club head shown in Figure 29, which has similar volume, mass, crown thickness, face thickness, and body structure to club head 100. The control club head has the same body structure as the exemplary club and a control insert that is different from the first insert. The control insert is a combination of solid materials and does not contain an aperture. The control insert fills only a portion of the cavity and does not fill any portion of the undercut.

[0191] Acoustic analysis was performed on both the seventh exemplary club head and a stock club head. To perform the test, the seventh exemplary club head was held stably, and a ball was struck against the club head at a constant speed typical of an average golfer's swing speed. Data was recorded using a microphone held near the club head during impact. Amplitude data against frequency was recorded, referring to Figures 50a and 50b. The seventh exemplary club head showed a significant reduction in peak amplitude at many frequencies, particularly at 2600 Hz. The maximum amplitude peak was reduced to less than one-quarter of the original value, and this reduction resulted in more consistent sound and feel before, during, and after impact, and significantly affected the vibrations felt by the golfer tactilely and audibly during impact. As a result, the sound produced by the seventh exemplary club head was much more subdued than that of the control club head.

[0192] VII. Comparison of club heads with top rail filling and club heads without top rail filling and heel, as described herein, with a control club head. Example VII presents the results of a comparison between a first exemplary club head, a second exemplary club head, and a control club head. Referring to Table 1, the club heads compared in this example are exemplary club head 1, exemplary club head 2, and the control club head. The first exemplary club head, as shown in Figure 12, has a hexagonal insert without a top rail filling and is described in Table 1 as exemplary club head 1. The second exemplary club head, as shown in Figure 11, has a hexagonal insert with a top rail filling and is described in Table 1 as exemplary club head 2. Exemplary club heads 1 and 2 have similar dimensions (length, width, height, depth, etc.), volume, mass, crown thickness, face thickness, and body structure to golf club head 100.

[0193] The first and second exemplary club heads were compared to a control club head shown in Figure 29, which has similar volume, mass, crown thickness, face thickness, and body structure to club head 100. The control club head has the same body structure as the exemplary club and a control insert that is different from the first insert. The control insert is a combination of solid materials and does not contain an aperture. The control insert fills only a portion of the cavity and does not fill any portion of the undercut.

[0194] The first exemplary club head, the second exemplary club head, and the control club head all accepted the same shaft. The same number of hits were performed for each of the first exemplary golf club, the second exemplary golf club, and the control golf club. Referring to Figures 51a–52c, ball speed, spin rate, and launch angle were recorded for each golf club.

[0195] Referring to Figure 51a, it was found that the average ball velocity of the second exemplary club head was approximately the same as that of the control club head. Specifically, the average ball velocity of the second exemplary club head was 0.1 mph (0.16 km / h) slower than that of the control club head. The recorded difference of 0.1 mph (0.16 km / h) in ball velocity is negligible and would likely be undetectable to a golfer or would not result in a substantial difference in distance.

[0196] Referring to Figure 51b, it was found that the average launch angle of the second exemplary club head was approximately the same as that of the control club head. Specifically, the average launch angle of the second exemplary club head was 0.1 degrees higher than that of the control club head.

[0197] Referring to Figure 51c, the average spin rate of the second exemplary club head was lower than that of the control club head. Specifically, the second exemplary club head had an average spin rate of 6264 rpm, while the control club head had an average spin rate of 6348 rpm.

[0198] Overall, the second exemplary club head did not exhibit a significant negative impact on performance compared to the control club head. When using the second exemplary club head, the differences measured in ball speed and launch angle were negligible compared to the control club head, while the spin reduction was approximately 1.3 percent.

[0199] Referring to Figure 52a, it was found that the average ball velocity of the first exemplary club head was similar to that of the control club head. Specifically, the average ball velocity of the first exemplary club head was 1 mph (1.61 km / h) slower (0.8% slower) than that of the control club head. The recorded difference in ball velocity of 1 mph (1.61 km / h) is negligible, resulting in a loss of distance traveled of approximately 2 yards (1.83 m).

[0200] Referring to Figure 52b, it was found that the average launch angle of the first exemplary club head was approximately the same as that of the control club head. Specifically, the average launch angle of the first exemplary club head was 0.6 degrees higher than that of the control club head.

[0201] Referring to Figure 52c, the average spin rate of the first exemplary club head was greater than that of the control club head. Specifically, the first exemplary club head had an average spin rate of 6396 rpm, while the control club head had an average spin rate of 6279 rpm.

[0202] Overall, the first exemplary club head did not exhibit a significant negative impact on performance compared to the control club head. When using the first exemplary club head, the differences measured in ball speed and launch angle were minor compared to the control club head, although the spin rate increase was approximately 1.9 percent. However, the performance difference exhibited by the second exemplary club head compared to the control club head was less than that of the first exemplary club head. The results for perceived performance, sound, and feel are described below, along with suggestions for improvements that would make the exemplary club heads more desirable to golfers than the control club heads while substantially maintaining the performance characteristics described above.

[0203] VIII. Player Survey - Comparison of a club head with a flexible heel, as described herein, with a control club head. Example VI presents the results of a comparison between the seventh exemplary club head and the control club head, which are the same two club heads compared in Example V. Referring to Table 1, the club heads compared in this example are exemplary club head 7 and the control club head. The seventh exemplary club head, as shown in Figure 8a, has a hexagonal insert with a heel bias gap and is described in Table 1 as exemplary club head 7. Exemplary club heads 1, 2, 3, 4, 5, and 6 are not considered in this example. Exemplary club head 7 has similar dimensions (length, width, height, depth, etc.), volume, mass, crown thickness, face thickness, and body structure to golf club head 100.

[0204] A seventh exemplary club head was compared to a control club head shown in Figure 29, which has similar volume, mass, crown thickness, face thickness, and body structure to club head 100. The control club head has the same body structure as the exemplary club and a control insert that is different from the first insert. The control insert is a combination of solid materials and does not contain an aperture. The control insert fills only a portion of the cavity and does not fill any portion of the undercut.

[0205] After hitting with each of the seventh exemplary club head and the control club head, the golfers completed a questionnaire regarding the perceived performance of the seventh exemplary club head and the control club head. As mentioned above, this survey was conducted immediately after the players participated in the test described in Example V. The survey instructed players to rate the importance of the subject matter of each question on a scale of 1 to 5 (5 being the most important). Next, players were instructed to rate their overall satisfaction with each club for each category on a scale of 1 to 5 (5 being the most satisfied).

[0206] The first five questions covered categories such as perceived ball speed, mis-hits, impact experience, and sound. The sixth question focused on overall satisfaction scores for both the exemplary and controllable club heads. The seventh question focused on overall satisfaction with the player's swing (this does not indicate any preference for a particular club).

[0207] Referring to Figure 53, on average, the surveyed golfers rated the seventh exemplary golf club higher than the control golf club in terms of perceived ball speed, minimization of extreme misses, flight path of mis-hits, feel and sound, impact experience, and overall satisfaction. These results indicate that, on average, golfers find the experience of the seventh exemplary golf club head to be significantly more favorable than the experience of the control golf club head.

[0208] The most noticeable differences perceived by players concerned the sound and feel they experienced. On average, players rated the seventh exemplary club head at a score of 4.30 and the control club head at a score of 3.62. This category was the second most important category according to the average of the golfers' ratings.

[0209] IX. Player Survey - Comparison of club heads with top rail filling and club heads without top rail filling and heel, as described herein, with a control club head. Example IX presents the results of a comparison between the same three club heads compared in Example VI: the first exemplary club head, the second exemplary club head, and the control club head. Referring to Table 1, the club heads compared in this example are exemplary club head 1, exemplary club head 2, and the control club head. The first exemplary club head, as shown in Figure 12, has a hexagonal insert without a top rail filling and is described in Table 1 as exemplary club head 1. The second exemplary club head, as shown in Figure 11, has a hexagonal insert with a top rail filling and is described in Table 1 as exemplary club head 2. Exemplary club heads 1 and 2 have similar dimensions (length, width, height, depth, etc.), volume, mass, crown thickness, face thickness, and body structure to golf club head 100.

[0210] The first and second exemplary club heads were compared to a control club head shown in Figure 29, which has similar volume, mass, crown thickness, face thickness, and body structure to club head 100. The control club head has the same body structure as the exemplary club and a control insert that is different from the first insert. The control insert is a combination of solid materials and does not contain an aperture. The control insert fills only a portion of the cavity and does not fill any portion of the undercut.

[0211] After hitting an equal number of times with each of the seventh exemplary club head and the control club head, the golfers completed two questionnaires regarding the perceived performance of the seventh exemplary club head and the control club head. These questionnaires were administered immediately after the players participated in the test described in Example VI. The questionnaires instructed players to rate the importance of the subject matter of each question on a scale of 1 to 5 (5 being the most important). Next, players were instructed to rate their overall satisfaction with each club for each category on a scale of 1 to 5 (5 being the most satisfied).

[0212] In both questionnaires, the first four questions covered categories such as perceived ball speed, mis-hits, impact experience, and sound. The fifth question concerned overall satisfaction scores for both the exemplary and controllable club heads. The sixth question concerned overall satisfaction with the player's swing (this does not indicate any preference for a particular club).

[0213] The first study (Figure 54) focused on golfers' perceptions of the second exemplary club head and the control club head. The second study (Figure 55) focused on golfers' perceptions of the first exemplary club head and the control club head.

[0214] The first study focused on the second exemplary club head and the control club head of Example VI. Referring to Figure 54, on average, the surveyed golfers rated the second exemplary golf club higher than the control golf club in terms of perceived ball speed, minimization of extreme misses, flight path of mis-hits, feel and sound, impact experience, and overall satisfaction. These results indicate that, on average, golfers find the experience of the second exemplary golf club head to be significantly more preferable than the experience of the control golf club head.

[0215] One of the most significant differences perceived by players concerned the sound and feel they experienced. On average, players rated the second exemplary club head at 4.20 and the control club head at 3.50. This category was the second most important category according to the average golfers' ratings.

[0216] The second study focused on the first exemplary club head and the control club head of Example VI. Referring to Figure 55, on average, the surveyed golfers rated the first exemplary golf club higher than the control golf club in terms of perceived flight path, feel and sound, impact experience, and overall satisfaction. These results indicate that, on average, golfers find the experience of the first exemplary golf club head to be significantly more favorable than the experience of the control golf club head.

[0217] One of the most significant differences perceived by players concerned the sound and feel they experienced. On average, players rated the first exemplary club head at 3.95 and the control club head at 3.60. This category was the most important, according to the average of the golfers' ratings.

[0218] Overall, golfers preferred the first and second exemplary club heads far more than the control club heads. The second exemplary club heads received a total rating of 16.83 in the four categories covered by the first four questions, while the control club heads received a total rating of 14.9 in the same test. Therefore, the second exemplary club heads were rated 13% higher than the control club heads. Golfers rated the second exemplary club higher than the first exemplary club heads. The first exemplary club heads received a total rating of 15.7 in the four categories covered by the first four questions, while the control club heads received a total rating of 15.0 in the same test. Therefore, the second exemplary club heads were rated 4.7% higher than the control club heads.

[0219] Because the rules of golf are subject to change from time to time (for example, new rules may be adopted or old rules may be eliminated or modified by the Golf Standardization Body and / or governing body), the golf equipment relating to the methods, apparatus, and / or products described herein may or may not conform to the rules of golf at any particular time. Accordingly, the golf equipment relating to the methods, apparatus, and / or products described herein may be advertised, marketed, and / or sold as golf equipment that conforms or does not conform to the rules. The methods, apparatus, and / or products described herein are not limited in this respect.

[0220] Although a specific order of actions has been described above, these actions may be performed in other time sequences. For example, two or more of the actions described above may be performed sequentially, in parallel, or simultaneously. Alternatively, two or more actions may be performed in reverse order. Furthermore, one or more of the actions described above may not be performed at all. The apparatus, methods, and products described herein are not limited in this respect.

[0221] While the present invention has been described in relation to various embodiments, it will be understood that the present invention is subject to further modifications. This application seeks to encompass any variations, uses, or adaptations of the present invention that generally follow the principles of the present invention and include such deviations from the disclosure as being within the scope of practice known in the art to which the invention relates.

Claims

1. It is an iron-type golf club head, The main unit and It includes an insert, The aforementioned main body is A striking face comprising a striking face perimeter and rear surface, It comprises a rear body having a toe section, a heel section, a top rail, and a sole, The rear body and the rear surface of the striking face define the cavity, The aforementioned rear body extends from around the striking face, The rear surface and rear body of the striking face form an undercut. The insert further comprises interconnecting walls, The interconnected walls form a void within the insert. The aforementioned void has a larger volume at the heel end of the insert than at the toe end. The periphery of the aforementioned insert is solid at the bottom and top portions. The cavity is configured to receive the insert, A golf club head, wherein the insert has a geometric shape that complements the geometric shape of the cavity, such that the insert fills the entire cavity and extends to the undercut portion.

2. The golf club head according to claim 1, wherein the insert abuts against the rear surface of the striking face and abuts against the rear body.

3. The golf club head according to claim 1, wherein the insert is made of a plurality of integrally formed pieces.

4. The golf club head according to claim 3, wherein the insert comprises an upper piece, a middle piece, and a lower piece.

5. The upper piece and the lower piece are integrally formed, and the undercut is filled. The golf club head according to claim 4, wherein the central portion is exposed within the cavity.

6. The golf club head according to claim 1, wherein the insert is compressed to fit into the cavity and the undercut.

7. The golf club head according to claim 1, wherein the insert does not extend beyond or protrude beyond the rear wall.

8. The golf club head according to claim 1, wherein the insert is made from a material selected from the list consisting of foam, polymer, and rubber.

9. It is an iron-type club head, The main unit and The insert comprises a front surface, a rear surface, a perimeter, a toe end, a heel end, a top portion, a bottom portion, and a perimeter. The aforementioned main body is A striking face comprising a striking face perimeter and rear surface, It comprises a rear body having a toe section, a heel section, a top rail, and a sole, The rear body and the rear surface of the striking face define a cavity, The aforementioned rear body extends in a curved shape from around the striking face, The rear surface and rear body of the striking face form an undercut. The insert further comprises interconnecting walls, The interconnected walls form a void within the insert. The periphery of the insert is solid at the top portion. The cavity is configured to receive the insert, The insert has a geometric shape that complements the geometric shape of the cavity, such that the insert fills the entire cavity and extends to the undercut portion. The top rail further comprises an aperture that extends to the undercut, The club head further comprises a projection that complements the aperture of the top rail of the insert.

10. The golf club head according to claim 9, wherein the insert abuts against the rear surface of the striking face and abuts against the rear body.

11. The golf club head according to claim 9, wherein the insert is made of a plurality of integrally formed pieces.

12. The golf club head according to claim 11, wherein the insert comprises an upper piece, a middle piece, and a lower piece.

13. The upper piece and the lower piece are integrally formed, and the undercut is filled. The golf club head according to claim 12, wherein the central portion is exposed within the cavity.

14. The golf club head according to claim 9, wherein the insert is compressed to fit into the cavity and the undercut.

15. The golf club head according to claim 9, wherein the insert does not extend beyond or protrude beyond the rear wall.

16. The golf club head according to claim 9, wherein the insert is made from a material selected from the list consisting of foam, polymer, and rubber.

17. It is an iron-type club head, It consists of a main body and an insert, The aforementioned main body is A striking face comprising a striking face perimeter and rear surface, It comprises a rear body having a toe section, a heel section, a top rail, and a sole, The rear body and the rear surface of the striking face define a cavity, The rear surface and rear body of the striking face form an undercut. The insert is divided into an upper undercut gasket, a lower undercut gasket, and a central portion. The upper undercut gasket is configured to be received in the top rail undercut, The lower undercut gasket is configured to be received by the sole undercut, The aforementioned central portion is a club head configured to be received in the cavity.

18. The golf club head according to claim 17, further comprising a badge layer which is located on the rear surface of the insert so as to be visible from the outside.

19. The golf club head according to claim 17, wherein the insert further comprises an adhesive layer configured to fix the insert to the rear surface of the striking face.

20. The badge layer is made of metal, as described in claim 18, for the golf club head.

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