Golf club head having energy storage characteristics

Abstract

To provide a golf club head having an energy storage property.SOLUTION: In several embodiments, a golf club head 300 includes a body. The body has a ball hitting face 312, a heel region, a toe region facing the heel region, a sole, a crown, and an inner diameter transition part 310 extending from the ball hitting face to at least either of the sole and the crown. In many embodiments, an inner diameter transition region cannot be seen from the outside of the golf club head, and has a first stage 315, a second stage 317, and a stage transition region 316 between the first stage and the second stage.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the benefit of U.S. Provisional Application No. 62 / 206,152, filed Aug. 17, 2015; U.S. Provisional Application No. 62 / 131,739, filed Mar. 11, 2015; U.S. Provisional Application 62 / 105,460, filed Jan. 20, 2015; U.S. Provisional Application 62 / 105,464, filed Jan. 20, 2015; and Provisional Application No. 62 / 068,232, filed Oct. 24, 2014, all of which are hereby incorporated by reference in their entirety.

[0002] This disclosure relates generally to golf clubs, and more particularly to golf club heads having energy storage characteristics.

Background Art

[0003] Golf club manufacturers have designed golf club heads to reduce stress on the hitting face of the golf club head. In many instances, these designs prevent the crown of the golf club head from flexing in the sole direction. Further, these designs are made such that the location of the peak of the bending of the golf club head upon impact with a golf ball does not change and no additional spring energy is stored. Additional spring energy can enable an increase in ball speed across the hitting face.

[0004] To facilitate further description of the embodiments, the following drawings are provided.

Brief Description of the Drawings

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Embodiments for Carrying Out the Invention

[0026] For simplicity and clarity of illustration, the figures show general aspects of the structure, and well-known features and descriptions and details of techniques may be omitted to prevent unnecessarily obscuring the golf club and its manufacturing method. Further, the members in the figures are not necessarily drawn to scale. For example, the dimensions of some members in the figures are exaggerated relative to other members to assist in improving the embodiments of the golf club and its manufacturing method. The same reference numerals in different figures denote the same members.

[0027] Terms such as "first", "second", "third", and "fourth" in the specification and claims, when present, are used to distinguish between similar members and do not necessarily describe a particular order or chronological sequence. It is understood that such terms are interchangeable with each other in appropriate circumstances such that the embodiments of the golf club and manufacturing method described herein can be operated in an order other than, for example, that described or recited herein. Further, the terms "contain", "include", and "have" and variations thereof are intended to include non-exclusive inclusion, and a process, method, article, or apparatus that includes a list of members is not necessarily limited to those members and may explicitly or inherently include other members not shown.

[0028] When terms such as "left", "right", "front", "back", "top", "bottom", "side", "lower", "upper", etc. appear in the specification and claims, they are used for illustrative purposes and do not necessarily describe permanent relative positions. It is understood that such terms used in this way are interchangeable with each other under appropriate circumstances where the embodiments of the golf club and the manufacturing method described in this specification can be operated in orientations other than, for example, those described or depicted in this specification. The term "connected" as used in this specification defines being connected directly or indirectly physically, mechanically, or by other means.

[0029] Description of Embodiment Examples Various embodiments of a golf club head having a stepped inner thin-walled portion include a golf club head having a body. The body has a hitting face, a heel region, a toe region opposite the heel region, a sole, a crown, and an inner diameter transition region from the hitting face to at least one of the sole or the crown. In many embodiments, the inner diameter transition region is not visible from the outside of the golf club head and has a first step, a second step, and a step transition region between the first and second steps.

[0030] Other embodiments of a golf club head having a stepped inner thin-walled portion include a golf club having a golf club head and a shaft connected to the golf club head. The golf club head has a hitting face, a heel region, a toe region opposite the heel region, a sole, a crown, and an inner diameter transition region from the hitting face to at least one of the sole or the crown. In many embodiments, the inner diameter transition region is not visible from the outside of the golf club head and has a first step, a second step, and a step transition region between the first and second steps.

[0031] Another embodiment of a golf club head having a stepped inner thin portion includes a method of manufacturing a golf club head. This method includes preparing a body. The body has a striking face, a heel region, a toe region opposite the heel region, a sole, and a crown. This method further includes preparing an inner diameter transition region from at least one of the sole or the crown to the striking face. The inner diameter transition region is not visible from the outside of the golf club head and has a first step, a second step, and a step transition region between the first step and the second step. In many embodiments, the first step has a first thickness, the second step has a second thickness, and the second thickness is thinner than the first thickness.

[0032] Various embodiments include a golf club head having a hollow body. The hollow body has a striking face, a heel region, a toe region opposite the heel region, a sole, and a crown. In many embodiments, the crown includes an upper region having a top rail and a lower region. In some embodiments, a cavity is disposed under the top rail and above the lower region of the crown and is at least partially defined by the upper and lower regions of the crown. In many embodiments, the cavity has a top wall, a rear wall, a bottom slope, a back cavity angle measured between the top wall and the rear wall of the cavity, and at least one channel.

[0033] Some embodiments include a golf club having a golf club with a hollow body and a shaft coupled to the golf club head with the hollow body. The golf club head with the hollow body has a striking face, a heel region, a toe region opposite the heel region, a sole, and a crown. In many embodiments, the crown includes an upper region having a top rail and a lower region. In some embodiments, a cavity is disposed under the top rail and above the lower region of the crown and is at least partially defined by the upper and lower regions of the crown. In many embodiments, the cavity has a top wall, a rear wall, a bottom slope, a back cavity angle measured between the top wall and the rear wall of the cavity, and at least one channel.

[0034] Other embodiments include a method of manufacturing a golf club head. In many embodiments, the method includes preparing a body. The body has a striking face, a heel region, a toe region opposite the heel region, a sole, and a crown. The crown includes an upper region having a top rail and a lower region. In some embodiments, a cavity is disposed under the top rail and over the lower region of the crown, with at least a portion defined by the upper and lower regions of the crown. In many embodiments, the cavity has a top wall, a rear wall adjacent to the top wall, a bottom ramp adjacent to the rear wall, a back cavity angle measured between the top and rear walls of the cavity, and at least one channel.

[0035] Other examples and embodiments are further disclosed herein. Such examples and embodiments can be found in the drawings, the claims, and / or this specification.

[0036] I. Golf Club Head with a Cascading Sole Turning to the drawings, FIG. 1 shows an embodiment of a golf club head 100. The golf club head 100 can be a wood-type golf club head. For example, the golf club head 100 can be a fairway wood-type golf club head, or a driver-type golf club head, or a hybrid-type golf club head, or an iron-type golf club head. The golf club head 100 has a body 101. The body 101 has a striking face 112, a heel region 102, a toe region 104, a sole 106, and a crown 108. In FIG. 1, the body 101 further has a skirt 110 extending between the sole 106 and the crown 108. In some embodiments, the body 101 does not have the skirt 110 or any skirt. FIG. 18 shows a front perspective view of a golf club 1800 according to an embodiment. In some embodiments, the golf club 1800 has a golf club head 100 and a shaft 190.

[0037] In some embodiments, the body 101 can be made of stainless steel, titanium, aluminum, alloy steel (e.g., 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), titanium alloy (e.g., Ti7-4, Ti6-4, T-9S), aluminum alloy, or a composite material. In some embodiments, the hitting face 112 can be made of stainless steel, titanium, aluminum, alloy steel (e.g., 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), titanium alloy (e.g., Ti7-4, Ti6-4, T-9S), aluminum alloy, or a composite material. In some embodiments, the body 101 can have the same material as the hitting face 112. In some embodiments, the body 101 can have a material different from that of the hitting face 112.

[0038] FIG. 2 shows a cross-section of the golf club head 100 along the section line II-II of FIG. 1 according to one embodiment. FIG. 2 shows an inner diameter transition portion 210 from the hitting face 112 to the sole 106 according to one embodiment. The inner diameter transition portion 210 can have a smooth transition, or the inner diameter transition portion 210 can have a cascaded sole with at least two steps or thickness heights. For example, the inner diameter transition portion 210 can include a cascaded sole having 2, 3, 4, 5, 6, or 7 steps. In some embodiments, the inner diameter transition portion can provide a greater bend of the hitting face 112. In some examples, the increase in the bend or deflection of the hitting face 112 can allow approximately 1% to approximately 3% more energy due to the deflection of the hitting face 112.

[0039] In many embodiments, the inner diameter transition portion 210 cannot be seen from outside the golf club head 100. FIG. 2 further shows a top inner diameter transition portion 260 from the hitting face 112 to the crown 108. In some embodiments, the top inner diameter transition portion 260 can have a smooth transition, while in other embodiments, the top inner diameter transition portion 260 can have at least two steps or thickness heights. For example, the top inner diameter transition portion 260 can have 2, 3, 4, 5, 6, or 7 steps or thickness heights. In some embodiments, the golf club head 100 can have an inner sole thickness 220. The inner sole thickness 220 can be thicker than the thinnest thickness of the inner diameter transition portion 210. In many embodiments, the inner sole thickness 220 is also thicker than an adjacent step or the final step of the inner diameter transition portion 210. In some embodiments, the inner sole thickness 220 can be thicker than the entire inner diameter transition portion 210.

[0040] In some embodiments, the inner diameter transition portion 210 can be made similar to the sole front portion and / or weight distribution channels as described in U.S. Patent No. 8,579,728, titled "Golf Club Heads with Weight Redistribution Channels and Related Methods", which is incorporated herein by reference.

[0041] In some embodiments, the golf club head can have a cascade transition region, a stepped transition region, or an inner diameter transition extending from the hitting face to at least one of the crown, heel, toe, sole, or skirt. In some embodiments, the golf club head can have a single continuous stepped transition region ring that surrounds the periphery of the golf club head and extends from the hitting face, for example, to each of the crown, toe region, heel region, and sole region. In other embodiments, the golf club head can have a stepped transition region only on the crown and / or the sole. In some embodiments, the golf club head can have a stepped transition region only on the toe region and / or the heel region. In other examples, the stepped transition region is disposed only from the hitting face to the skirt. In other embodiments, the golf club head has separate or individual stepped transition regions from the hitting face to the toe region of the crown, the heel region of the crown, the toe region of the sole, and / or the heel region of the sole.

[0042] FIG. 3 shows a view of an inner diameter transition 310 of a golf club head 300 according to another embodiment similar to the golf club head of FIG. 1, along a cross-sectional line similar to cross-sectional line II-II of FIG. 1. FIG. 4 shows a view of an inner diameter transition 410 of a golf club head 400 according to another embodiment similar to the golf club head of FIG. 1, along a cross-sectional line similar to cross-sectional line II-II of FIG. 1. FIG. 5 shows a view of an inner diameter transition 510 of a golf club head 500 according to another embodiment similar to the golf club head of FIG. 1, along a cross-sectional line similar to cross-sectional line II-II of FIG. 1.

[0043] As shown in FIG. 3, the inner diameter transition portion 310 can be similar to the inner diameter transition portion 210 (FIG. 2), and the golf club head 300 can be similar to the golf club head 100 (FIGS. 1 and 2). The inner diameter transition portion 310 includes a first stage 315 having a first thickness and a second stage 317 having a second thickness. In many embodiments, the thickness of each stage is substantially constant in practice. For example, the first thickness of the first stage 315 can have a first substantially constant thickness, and the second thickness of the second stage 317 can have a second substantially constant thickness. In other embodiments, the first stage 315 can have a first gradient, and the first thickness of the first stage 315 is thicker closer to the hitting face 312 and thinner closer to the stage transition region 316. The stage transition region 316 can have a stage gradient that is steeper than the first gradient of the first stage 315. The stage transition region 316 slopes linearly at an angle smaller than 90 degrees and can transition from the first stage 315 to the second stage 317. In other embodiments, the stage transition region 316 can have a step of approximately 90 degrees, as shown in the stage transition regions 516 and 518 of FIG. 5. The stage transition regions 516 (FIG. 5) and 518 (FIG. 5) can be similar to the stage transition region 316 (FIG. 3), and the stage transition regions 416 (FIG. 4) and 418 (FIG. 4).

[0044] As shown in FIG. 4, in some embodiments, each stepped transition portion 316, 416, 418, 516, 518 can have a first arcuate surface 420 and a second arcuate surface 422. The first arcuate surface 420 has a first radius of curvature, and the second arcuate surface 422 has a second radius of curvature. The first radius of curvature and the second radius of curvature of each stepped transition portion 316, 416, 418, 516, 518 can be the same, or the first radius of curvature and the second radius of curvature of each stepped transition portion 316, 416, 418, 516, 518 can be made different. For example, the first radius of curvature of the first arcuate surface 420 can be the same as the second radius of curvature of the first arcuate surface 420, the first radius of curvature of the first arcuate surface 420 can be smaller than the second radius of curvature of the first arcuate surface 420, or the first radius of curvature of the first arcuate surface 420 can be larger than the second radius of curvature of the first arcuate surface 420. Further, for example, the first radius of curvature of the second arcuate surface 422 can be the same as the second radius of curvature of the second arcuate surface 422, the first radius of curvature of the second arcuate surface 422 can be smaller than the second radius of curvature of the second arcuate surface 422, or the first radius of curvature of the second arcuate surface 422 can be larger than the second radius of curvature of the second arcuate surface 422.

[0045] Furthermore, each stepped transition portion 316, 416, 418, 516, 518 can have the same first radius of curvature or different first radii of curvature. Further, each of the stepped transition portions 316, 416, 418, 516, 518 can have the same second radius of curvature or different second radii of curvature. For example, the first radius of curvature of the first arcuate surface 420 can be the same as the first radius of curvature of the second arcuate surface 422, the first radius of curvature of the first arcuate surface 420 can be smaller than the first radius of curvature of the second arcuate surface 422, or the first radius of curvature of the first arcuate surface 420 can be larger than the first radius of curvature of the second arcuate surface 422. Further, for example, the second radius of curvature of the first arcuate surface 420 can be the same as the second radius of curvature of the second arcuate surface 422, the second radius of curvature of the first arcuate surface 420 can be smaller than the second radius of curvature of the second arcuate surface 422, or the second radius of curvature of the first arcuate surface 420 can be larger than the second radius of curvature of the second arcuate surface 422.

[0046] The inner diameter transition function (e.g., the inner stepped transition portion 310, FIG. 3) can change the location where the bending peak of the golf club head occurs. The stepped transition region can generate a "plastic hinge" at the bending peak and facilitate more localized deformation due to impact with the golf ball. In many embodiments, the buckling process starts at the bending peak position, and the golf club head is optimized to stay just below the critical buckling threshold. The inner plastic hinge allows the club to flex more in the crown and sole directions. The inner plastic hinge makes it possible to accurately control the position and amount of flexure of the crown and sole by using the stepped function.

[0047] Using the inner diameter transition portion makes it possible to distribute the stress of the golf club head over a greater volume of the material, thus reducing the local peak stress. In many embodiments, the additional flexure from the crown to the sole allows the face to further bend based on the same load. This additional flexure generates more stress and bending in the club face and can generate more spring energy. The increase in spring energy can be stored within the golf club head upon impact with the golf ball. In many embodiments, the additional spring energy aids in increasing the speed of the ball. In some embodiments, the inner diameter transition portion can form a more global flexure within the golf club head, which can also lead to an increase in the speed of the ball. When the ball speed across the entire hitting face increases, better distance control is possible. In some embodiments, a golf club head having an inner diameter transition function can store about 4% to about 6% more energy, which can be returned to the golf ball.

[0048] Returning to FIG. 3, the inner diameter transition portion 310 can change the position where the bending peak 350 of the sole of the golf club head 300 occurs. Further, the inner diameter transition portion 310 can engage more of the body of the club head 300 in the bending process during impact from the golf ball. In some embodiments, the first stage 315 and the second stage 317 allow a portion of the stress generated by the impact between the hitting face 312 and the golf ball to be stored in each stage. This structure prevents stress from mainly concentrating on the thinnest part of the sole and allows the reliability and durability of the golf club head 300 to be increased. In many embodiments, this structure creates a plastic hinge opposite the hitting face end of the inner diameter transition portion 310 and promotes further localization of deformation at the plastic hinge location. In many embodiments, the plastic hinge can be located at the bending peak, such as the bending peak 350. This structure also allows, for example, more potential energy to be stored by the crown and / or the sole. In some embodiments, the body 301 can experience an increase in deflection or bending in the direction from the crown to the sole in the deflection or bending of the sole and the crown of about 4% to about 7%. The additional deflection in the direction from the crown to the sole in the sole and / or the crown allows the hitting face 312 to bend further with the same load or impact by the golf ball. Thus, this structure can generate more stress and bending in the hitting face 312 of the golf club head 300 that can be transmitted to the ball upon impact with the hitting face 312.

[0049] In some embodiments, each step has a generally constant thickness throughout the step. In many embodiments, the first step 315 is thicker than the second step 317. In some embodiments of a driver type golf club head, the first step 315 can have a thickness of from about 0.030 inches (0.076 cm) to about 0.060 inches (0.152 cm), or from about 0.040 inches (0.102 cm) to about 0.050 inches (0.127 cm), and the second step 317 can have a thickness of from about 0.020 inches (0.051 cm) to about 0.050 inches (0.127 cm), or from about 0.030 inches (0.076 cm) to about 0.040 inches (0.102 cm). In some embodiments of a fairway wood type golf club head, the first step 315 can have a thickness of from about 0.035 inches (0.089 cm) to about 0.065 inches (0.165 cm), or from about 0.045 inches (0.114 cm) to about 0.055 inches (0.140 cm), and the second step 317 can have a thickness of from about 0.025 inches (0.064 cm) to about 0.055 inches (0.140 cm), or from about 0.035 inches (0.089 cm) to about 0.045 inches (0.114 cm). In some embodiments of a hybrid type golf club head, the first step 315 can have a thickness of from about 0.050 inches (0.127 cm) to about 0.080 inches (0.203 cm), or from about 0.060 inches (0.152 cm) to about 0.070 inches (0.178 cm), and the second step 317 can have a thickness of from about 0.040 inches (0.102 cm) to about 0.070 inches (0.178 cm), or from about 0.050 inches (0.127 cm) to about 0.060 inches (0.152 cm).In many embodiments of an iron-type golf club head, the first step 315 can have a thickness of from about 0.055 inches (0.140 cm) to about 0.085 inches (0.216 cm), or from about 0.060 inches (0.152 cm) to about 0.080 inches (0.203 cm). The second step 317 can have a thickness of from about 0.045 inches (0.114 cm) to about 0.075 inches (0.191 cm), or from about 0.050 inches (0.127 cm) to about 0.070 inches (0.178 cm).

[0050] In other embodiments, such as those shown in FIG. 4, the inner diameter transition portion 410 can have more than two steps. For example, the inner diameter transition portion 410 can have 2, 3, 4, 5, 6, or 7 steps. A three-step inner diameter transition portion 410 can be made similar to the inner diameter transition portion 310 (FIG. 3) and have a first step 415, a second step 417, and a third step 419. The first step 415 can be made similar to the first step 315 of FIG. 3, and the second step 417 can be made similar to the second step 317. In many embodiments, the bending peak 450 occurs further rearward from the hitting face 412 as more steps are added to the inner diameter transition portion.

[0051] In many embodiments, the second step 417 is thicker than the third step 419. In some embodiments of a driver type golf club head, the third step 419 has a thickness of from about 0.010 inches to about 0.040 inches (0.102 cm), or from about 0.020 inches (0.051 cm) to about 0.030 inches (0.076 cm). In some embodiments of a fairway wood type golf club head, the third step 419 has a thickness of from about 0.015 inches (0.038 cm) to about 0.045 inches (0.114 cm), or from about 0.025 inches (0.064 cm) to about 0.035 inches (0.089 cm). In some embodiments of a hybrid type golf club head, the third step 419 has a thickness of from about 0.030 inches (0.076 cm) to about 0.060 inches (0.152 cm), or from about 0.040 inches (0.102 cm) to about 0.050 inches (0.127 cm). In some embodiments of an iron type club head, the third step 419 has a thickness of from about 0.030 inches (0.076 cm) to about 0.060 inches (0.152 cm), or from about 0.035 inches (0.089 cm) to about 0.055 inches (0.140 cm).

[0052] On the one hand, referring to FIG. 5, in some embodiments of a driver-type golf club head, the first stage 515 can have a thickness of about 0.045 inches (0.114 cm), the second stage 517 can have a thickness of about 0.035 inches (0.089 cm), and the third stage 519 can have a thickness of about 0.025 inches (0.064 cm). In some embodiments of a fairway wood-type golf club head, the first stage 515 can have a thickness of about 0.051 inches (0.130 cm), the second stage 517 can have a thickness of about 0.039 inches (0.099 cm), and the third stage 519 can have a thickness of about 0.030 inches (0.076 cm). In some embodiments of a hybrid-type golf club head, the first stage 515 can have a thickness of about 0.067 inches (0.170 cm), the second stage 517 can have a thickness of about 0.054 inches (0.137 cm), and the third stage 519 can have a thickness of about 0.045 inches (0.114 cm). In some embodiments of an iron-type golf club head, the first stage 515 can have a thickness of about 0.067 inches (0.170 cm), the second stage can have a thickness of about 0.057 inches (0.145 cm), and the third stage 519 can have a thickness of about 0.042 inches (0.107 cm).

[0053] In some embodiments, the first stage lengths of the first stages 315, 415, 515 in FIGS. 3, 4, and 5 can be approximately equal to the second stage lengths of the second stages 317, 417, 517 in FIGS. 3, 4, and 5, respectively. In some embodiments, the first stage lengths of the first stages 315, 415, 515 in FIGS. 3, 4, and 5 are longer than the second stage lengths of the second stages 317, 417, 517, respectively. In other embodiments, the second stage lengths of the second stages 417, 517 in FIGS. 4 and 5 can be approximately equal to the third stage lengths of the third stages 419, 519 in FIGS. 4 and 5, respectively. In some embodiments, the second stage lengths of the second stages 417, 517 in FIGS. 4 and 5 can be longer than the third stage lengths of the third stages 419, 519 in FIGS. 4 and 5, respectively. In other embodiments, the second stage lengths of the second stages 417, 517 in FIGS. 4 and 5 can be shorter than the third stage lengths of the third stages 419, 519 in FIGS. 4 and 5, respectively.

[0054] Referring to FIGS. 3, 4 and 5, in some embodiments of a fairway wood type golf club head or a driver type golf club head or a hybrid type golf club head, the first stage 315, 415, 515 can have a first stage length of from about 0.05 inches (0.127 cm) to about 0.80 inches (2.03 cm), the second stage 317, 417, 517 can have a second stage length of from about 0.03 inches (0.076 cm) to about 0.60 inches (1.52 cm), and the third stage 419, 519 can have a third stage length of from about 0.04 inches (0.102 cm) to about 0.70 inches (1.78 cm). In some embodiments of an iron type golf club head, the first stage 315, 415, 515 can have a first stage length of from about 0.03 inches (0.076 cm) to about 0.30 inches (0.762 cm), the second stage 317, 417, 517 can have a second stage length of from about 0.04 inches (0.102 cm) to about 0.40 inches (1.02 cm), and the third stage 419, 519 can have a third stage length of from about 0.05 inches (0.127 cm) to about 0.50 inches (1.27 cm).

[0055] As shown in FIGS. 3, 4, and 5, in some embodiments, the first and second arcuate surfaces of the stepped transition portions 316, 416, 516 can have first and second radii of curvature that are at least twice as large as the difference between the first thickness T1 and the second thickness T2 of the first step 315, 415, 515 and the second step 317, 417, 517, respectively. In one embodiment, the first and second arcuate surfaces of the stepped transition portions 316, 416, 516 have first and second radii of curvature that are approximately 6.5 times as large as the difference between the first thickness T1 and the second thickness T2 of the first step 315, 415, 515 and the second step 317, 417, 517, respectively. As shown in FIGS. 4 and 5, in some embodiments, the first and second arcuate surfaces of the stepped transition portions 418, 518 can have first and second radii of curvature that are at least twice as large as the difference between the second thickness T2 and the third thickness T3 of the second step 417, 517 and the third step 419, 519, respectively. In one embodiment, the first and second arcuate surfaces of the stepped transition portions 418, 518 have first and second radii of curvature that are approximately 6.5 times as large as the difference between the second thickness T2 and the third thickness T3 of the second step 417, 517 and the third step 419, 519, respectively.

[0056] As shown in FIG. 3, some embodiments, such as a golf club head 300, have a weight pad 330 that lowers the center of gravity of the golf club head 300. The weight pad 330 has a weight pad thickness 331 that is greater than the final step thickness 321 of the adjacent step. In this example, the adjacent step is the second step 317. In many embodiments having the weight pad 330, the inner sole thickness 320 can be approximately equal to the final step thickness 321. In some embodiments, the inner sole thickness 320 can be thicker than the final step thickness 321. In some embodiments, the inner sole thickness 320 is thinner than the final step thickness 321.

[0057] As shown in FIG. 4, some embodiments, such as golf club head 400, have ribs 440. The ribs 440 can be arranged inside the body 401 and substantially parallel to the hitting face. In many embodiments, the ribs 440 can be ridges or bars. In some embodiments, the ribs 440 can have a rib thickness 441 that is thicker than the third stage thickness 421, the thickness of an adjacent stage, or the thickness of the final stage of the inner diameter transition portion 410. The purpose of the ribs 440 is to reinforce the sole of the golf club head 400, and thus, the peak of the sole bending occurs at the step transition region 416 and / or the step transition region 418.

[0058] Moving on to FIG. 6, in some embodiments, the golf club head 600 can have a crown inner diameter transition portion 660 at the crown 608. The crown inner diameter transition portion 660 can be similar to the inner diameter transition portion 310 of FIG. 3, except that the crown inner diameter transition portion 660 is arranged on the hitting face for the crown transition portion instead of the hitting face for the sole transition portion. In many embodiments, the first stage 615 can be similar to the first stages 315, 415, and / or 515 of FIGS. 3, 4, and 5 respectively, the second stage 617 can be similar to the second stages 317, 417, and / or 517 of FIGS. 3, 4, and 5 respectively, the third stage 619 can be similar to the third stages 419 and / or 519 of FIGS. 4 and 5 respectively, and the step transition regions 616 and / or 618 can be similar to the step transition regions 316, 416, 516, 418, and / or 518 of FIGS. 3, 4, and 5. Similarly, the crown inner diameter transition portion 660 can have a plurality of inner diameter transition portions and can form more than two stages. For example, the crown inner diameter transition portion 660 can have 2, 3, 4, 5, 6, or 7 stages.

[0059] In FIG. 7, the golf club head 700 can have a skirt inner diameter transition portion 780 as shown in FIG. 7. FIG. 7 shows a cross-sectional view of a golf club 700 similar to the golf club head 100 (FIG. 1) along a cross-sectional line similar to cross-sectional line VII-VII of FIG. 1 according to another embodiment. The skirt inner diameter transition portion 780 can be similar to the inner diameter transition portion 210 (FIG. 2), the first stage 715 can be similar to the first stages 315, 415 and / or 515 of FIGS. 3, 4 and 5 respectively, the second stage 717 can be similar to the second stages 317, 417 and / or 517 of FIGS. 3, 4 and 5, the third stage 719 can be similar to the third stages 419 and / or 519 of FIGS. 4 and 5 respectively, and the stage transition regions 716 and / or 718 can be similar to the stage transition regions 316, 416, 516, 418 and / or 518 of FIGS. 3, 4 and 5. Similarly, the skirt inner diameter transition portion 780 can have more than two stages. For example, the skirt inner diameter transition portion 780 can have 2, 3, 4, 5, 6 or 7 stages. As shown in FIG. 7, the golf club head 700 can also have a skirt inner diameter transition portion on the other side of the hitting face 712. In other embodiments, the golf club head 700 can have a skirt inner diameter transition portion on one side of the hitting face 712.

[0060] FIG. 8 shows a partial view of a golf club head 800 similar to the golf club head 400 (FIG. 4) according to an embodiment, and a view of the same area of a standard golf club head 850. The standard golf club head 850 has a uniform sole thickness 855 from the hitting face 852 to the sole 856 and an inner sole weight 870 that is thicker than the uniform sole thickness 855. The golf club head 800 has an inner diameter transition portion 810 similar to the inner diameter transition portion 410 (FIG. 4). The inner diameter transition portion 810 can have a first stage 815 similar to the first stage 415 (FIG. 4), a second stage 817 similar to the second stage 417 (FIG. 4), and a third stage 819 similar to the third stage 419 (FIG. 4). The inner diameter transition portion 810 can further have step transition regions 816, 818 similar to the step transition regions 416 (FIG. 4) and 418 (FIG. 4), and an inner sole weight 820 similar to the inner sole weight 870. In many embodiments, at least one of the first stage 815, the second stage 817, or the third stage 819 can be thinner than the uniform sole thickness 855. The thickness of the steps can eliminate weights that can be redistributed later in the club head.

[0061] Over a larger area of the sole 806 having the inner diameter transition region 810, higher stress is more evenly distributed than in the sole 856 without a cascaded sole. In many embodiments, the overall curvature of the sole similar to the uniform sole thickness 855 can absorb a greater specific concentration of impact force from the golf ball in a particular region, but does not distribute the force over a larger area. A cascaded structure such as the inner diameter transition 810 (or a step where the thickness changes along the inner diameter transition) however provides a technique for "packaging" the impact force from the golf ball over a larger area, as the wavy or stepped structure transfers a greater stress from one inner diameter region of a particular thickness to the next. In many embodiments, there is stress bleeding, overflow or retention across the inner diameter transition 810 or the cascaded thin sole. The greater distribution of the higher stress forms a greater recoil force on the hitting face. Retaining stress in the inner diameter transition 810 can also prevent all of the stress from directly converging at the thinnest step. In many embodiments, the stepped function can assist in preventing stress from being distributed along the sole and a single large stress concentration from occurring. Instead, there are multiple stress concentrations for a more even distribution of stress. The stress extends along the cascaded sole, allowing the sole to experience more stress acting (or being absorbed). However, the stress decreases at the thickest part of the sole without a cascaded sole, experiences the maximum level of stress, and applies a smaller rebounding force to the hitting face.

[0062] Embodiments of golf club heads having a cascade sole (e.g., 100, 300, 400, 500, 600, or 700) were tested in comparison to similar control club heads without a cascade sole. Club heads having a cascade sole showed an increase in ball speed of about 0.5 - 1.5 miles per hour (mph) (0.8 - 2.4 kilometers per hour (kph), or about 0.5 - 0.9% of the ball speed), compared to the control club heads. The increase in ball speed for impacts at the center was about 0.5 - 1.0 mph (0.8 - 1.6 kph), and the increase in ball speed for off - center impacts was about 1 - 1.5 mph (1.6 - 2.4 kph). Club heads having a cascade sole further showed an increase in launch angle of about 0.1 - 0.3 degrees, a decrease in spin of about 275 - 315 revolutions per minute (rpm), and an increase in carry distance of about 3 - 6 yards (2.7 - 5.5 meters), compared to the control club heads.

[0063] In some embodiments, golf club heads having a driver - type, hybrid - type, or wood - type cascade sole (e.g., 100, 300, 400, 500, 600, or 700) may further have a first crown thickness (not shown) and a second crown thickness (not shown). The first crown thickness may be located at the crown on the back of the hitting face or at the crown inner diameter transition. The second crown thickness may be located on the crown towards the rear of the club head behind the first crown thickness. The first crown thickness is thicker than the second crown thickness. Further, the first crown thickness may gradually transition according to any outer shape towards the second crown thickness, or the first crown thickness may abruptly transition to the second crown thickness, for example, like a step.

[0064] The first crown thickness may be any portion of the crown at the front end of the clubhead. For example, the first crown thickness may be 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, or any portion of the crown at the front end of the clubhead. The second crown thickness may be any portion of the crown at the rear of the clubhead. For example, the second crown thickness may be 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% or any portion at the rear of the clubhead.

[0065] The crown thickness may transition between the first crown thickness and the second crown thickness at any portion of the crown of the clubhead, defining a crown thickness transition section. The crown thickness transition section may be of any shape. In an exemplary embodiment, the crown thickness transition section defines a bell-shaped curve similar to that of U.S. Patent No. 7,892,111, which is incorporated herein by reference. The first crown thickness is disposed on the crown between the hitting face and the bell-shaped curve, and the second crown thickness is disposed between the bell-shaped curve and the rear of the clubhead.

[0066] In an exemplary embodiment, when the golf clubhead is a fairway wood type golf clubhead, the first crown thickness is about 0.022 inches (0.056 cm) and the second crown thickness is about 0.019 inches (0.048 cm). Further, in an exemplary embodiment, when the golf clubhead is a hybrid type golf clubhead, the first crown thickness is about 0.024 inches (0.061 cm) and the second crown thickness is about 0.019 inches (0.048 cm).

[0067] In other embodiments of a fairway wood type or hybrid type golf club head, the first crown thickness is less than about 0.029(0.074), 0.028(0.071), 0.027(0.069), 0.026(0.066), 0.025(0.064), 0.024(0.061), 0.023(0.058), 0.022(0.056), 0.021(0.053), 0.020(0.051), 0.019(0.048), 0.018(0.046), or 0.017(0.043) inches (cm), and the second crown thickness may be less than about 0.024(0.061), 0.023(0.058), 0.022(0.056), 0.021(0.053), 0.020(0.051), 0.019(0.048), 0.018(0.046), 0.017(0.043), 0.016(0.041), 0.015(0.038), 0.014(0.036), 0.013(0.033), or 0.012(0.031) inches (cm).

[0068] The crown inner diameter transition portion dissipates and / or reduces the stress of the crown of the club head, whereby the first and second crown thicknesses are reduced compared to the previous design. In an exemplary embodiment, compared to the previous design, the first crown thickness is reduced by about 17.2 - 24.1%, and the second crown thickness is reduced by about 20.8%. The reduction of the first and second crown thicknesses enables the center of gravity of the club head to be lowered (placed closer to the sole) compared to the previous design. The lowering of the center of gravity of the club head improves the performance characteristics of the club head by reducing the ball's gear effect and spin.

[0069] Moving to FIG. 9, various embodiments of a golf club head having a stepped inner thin-walled portion include a method 900 of manufacturing a golf club head. Method 900 includes preparing a body (block 910). The body has a striking face, a heel region, a toe region opposite the heel region, a sole, and a crown. In some embodiments, the body further has a skirt extending from the crown to the sole. Method 900 further includes providing an inner diameter transition portion from the striking face to at least one of the sole, the crown, or the skirt (block 920). Method 900 further includes providing a first stage of the inner diameter transition portion (block 930), providing a second stage to the inner diameter transition portion (block 940), and providing a step transition region between the first stage and the second stage of the inner diameter transition region (block 950). In some embodiments, blocks 910, 920, 930, 940, and 950 can be performed simultaneously with each other, such as by casting the body of the club head. In other embodiments, one or more of blocks 920, 930, 940, and / or 950 can be performed after block 910 through a machining process, by way of example.

[0070] II. Golf Club Head Having a Back Cavity In one embodiment, the golf club head has a back cavity disposed in the upper crown region of the golf club. In many embodiments, the back cavity can provide a box spring effect when striking a golf ball. The back cavity can provide a spring-like effect in combination with a change in the thickness of the inner diameter of the sole of the club head (cascaded sole).

[0071] Some embodiments are directed to club heads (hybrids or fairway woods or irons having a hollow design) featuring a hollow structure club head that provides a more "iron-like" appearance and feel. In some embodiments, the golf club head can feature a flat hitting face and an iron-like outer shape, which can provide improved workability and accuracy similar to an iron. A back cavity disposed below the top rail of the club head and along the lower crown is designed for hybrids, fairway woods, and irons having a hollow structure. The back cavity may be a full channel along the upper crown or rear directly below the top rail of the club head from heel to toe. The top rail and cavity can be of any design. In some embodiments, the cavity has an angle of about 90 degrees and provides a targeted hinge point in the crown region of the golf club head. This hinge or buckling region allows the top rail to absorb greater impact forces over a large volume area and, when returning the cavity and top rail to their original positions, acts as a springboard with a greater recoil force back to the hitting face, thereby enabling a greater force to be imparted to the ball. The large club face deflection resulting from this cavity design reduces spin, increases the loft angle of the golf ball at impact, and further can increase ball speed at the same club speed compared to a standard golf club head.

[0072] In a standard hybrid club head, the top rail and the upper crown region do not have the cavity of this design. In comparison with the present disclosure, the bending or deflection of the hitting face in such a standard hybrid club head is less. Since the standard hybrid does not have a cavity, less energy is transmitted to the top rail of the club, so a large spring-back effect cannot be obtained. The golf club head having the disclosed back cavity can absorb a greater impact force of the golf ball and then return it to the hitting face. In many embodiments, the angle of the cavity can provide a buckling point, or a plastic hinge, or a target hinge for the hitting face to deflect more than a standard golf club.

[0073] The recoil effect of the cavity on the hitting face is as follows: (1) a higher golf ball speed for the same club head speed of a club head with an upper crown cavity (or back cavity) compared to one without, which is partly due to the spring effect transmitted from the hinge region to the ball on the hitting face; (2) less spin of the golf ball after impact with the club, which is partly due to the hinge point at the top of the cavity reacting to a greater force absorbed by the club and instead transmitting a greater force to the ball, thereby preventing the ball from spinning backward from the hitting face; (3) a greater loft angle for the golf ball at impact, which is due to the hinge and the hitting face acting as a diving board or catapult on the ball. In some embodiments, the cavity can increase the ball speed by about 1.0 - 1.2% and increase the launch angle by about 0.4 - 0.7 degrees.

[0074] Moving to the figures, FIG. 10 shows a rear toe-side perspective view of an embodiment of a golf club head 1000, and FIG. 11 shows a rear heel-side perspective view of the golf club head 1000 according to the embodiment of FIG. 10. The golf club head 1000 can be a hybrid type golf club head. In other embodiments, the golf club head 1000 can be an iron type golf club head or a fairway wood type golf club head. In many embodiments, the golf club head 1000 does not have a badge or an individually prepared port.

[0075] The golf club head 1000 has a body 1001. In many embodiments, the body is hollow. In some embodiments, the body is at least partially hollow. The body 1001 has a striking face 1012, a heel region 1002, a toe region 1004 opposite the heel region 1002, a sole 1006, and a crown 1008. The crown 1008 has an upper region 1011 and a lower region 1013. The upper region 1011 has a top rail 1015. In some embodiments, the top rail 1015 can be flat and can be a higher top rail or a skirt. The reason for the flat and higher top rail to increase playability from the tee for a mishit on the striking face 1012 is explained.

[0076] In some embodiments, the body 1001 can be made of stainless steel, titanium, aluminum, alloy steel (e.g., 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), titanium alloy (e.g., Ti7-4, Ti6-4, T-9S), aluminum alloy, or composite material. In some embodiments, the hitting face 1012 can be made of stainless steel, titanium, aluminum, alloy steel (e.g., 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), titanium alloy (e.g., Ti7-4, Ti6-4, T-9S), aluminum alloy, or composite material. In some embodiments, the body 1001 can have the same material as the hitting face 1012. In some embodiments, the body 1001 can have a different material from the hitting face 1012.

[0077] In many embodiments, the cavity 1030 is disposed below the top rail 1015. In many embodiments, the cavity 1030 has a top box spring design. In many embodiments, the top rail 1015 and the cavity 1030 provide an overall increase in the bending of the hitting face 1012. In some embodiments, the bending of the hitting face 1012 allows for an energy increase of about 2% to about 5%. The cavity 1030 enables the hitting face 1012 to be made thinner and allows for additional overall bending. For some fairway wood type golf club head embodiments, the cavity 1030 can be a reverse scoop or indentation of the crown 1008 that is thicker towards the sole 1006.

[0078] Referring to FIG. 10, in some embodiments, the golf club head 1000 can further have an insert 1062 in the lower region 1013 of the crown 1008 near the toe region 1004. Some embodiments have an internal weight on the sole 1006. In many embodiments, the insert 1062 may comprise tungsten or other high-density materials. In many embodiments, the insert moves the center of gravity (CG) approximately 0.04 inches (1 mm) to 0.10 inches (2.5 mm) rearward from the hitting face 1012 and increases the launch angle by 3.5% to 5.5%, which can improve the playability of high or low mishits from the tee.

[0079] In many embodiments, the CG is in the lower region 1013 of the crown 1008 near the intersection of the toe region 1004 and the sole 1006. In some embodiments, the CG of the golf club head 1000 is at 0.597 inches along the CGy plane and 0.541 inches along the CGz plane. For the moment of inertia Ixx, the golf club head 1000 increased by 20.5% compared to the G30 iron and by 28% compared to the Rapture DI. For Iyy, it increased by 1.7% compared to the G30 iron and by 22% compared to the Rapture DI.

[0080] In some embodiments, from about 3 grams (g) to about 4 g is added to the top rail 1015. In most embodiments, the total mass of the golf club head 1000 remains the same. In some embodiments, mass can be removed from the sole 1006 or the toe region 1004 to offset the addition of mass to the top rail 1015. In some embodiments, adding from about 3 g to about 4 g of mass to the top rail 1015 can assist in a golf club head that resists rotation. In some embodiments, the CG of the golf club head rises slightly.

[0081] FIG. 12 shows a cross-section of the golf club head 1000 along the sectional line XII-XII of FIG. 10 according to one embodiment. As shown in FIG. 12, the hitting face 1012 has a high region 1076, a middle region 1074, and a low region 1072. In many embodiments, the upper region 1011 of the crown 1008 has a rear wall 1023, a top wall 1017 of the cavity 1030 adjacent and below the rear wall 1023, and a rear wall 1019 of the cavity 1030 adjacent and below the top wall 1017.

[0082] In some embodiments, the height 1280 of the rear wall 1023 of the upper region 1011 of the crown 1008 can be from about 0.125 inches (0.318 cm) to about 0.75 inches (1.91 cm), or from about 0.150 inches (0.381 cm) to about 0.400 inches (1.02 cm). For example, in some embodiments, the height 1280 of the rear wall 1023 of the upper region 1011 of the crown 1008 can be about 0.175 inches (0.445 cm), 0.275 inches (0.699 cm), 0.375 inches (0.953 cm), 0.475 inches (1.21 cm), 0.575 inches (1.46 cm), or 0.675 inches (1.71 cm). In some embodiments, the height 1280 of the rear wall 1023 of the upper region 1011 of the crown 1008 can be from about 5% to about 25% of the height of the golf club head 1000. In some embodiments, the length of the top rail 1015 can be from about 70% to about 95% of the length of the golf club head 1000 as measured from the heel region 1002 to the toe region 1004.

[0083] The height 1280 of the rear wall 1023 of the upper region 1011 of the crown 1008 allows at least a portion of the stress of the hitting face 1012 during impact with a golf ball to be absorbed by the cavity 1030 as described herein. A golf club head having a rear wall with a height higher than the rear wall height 1280 described herein has an increased dispersion of impact along the top rail before reaching the cavity, resulting in less stress absorption during impact (and less deflection of the hitting face) than the golf club head 1000 described herein.

[0084] In some embodiments, the cavity 1030 is disposed above the lower region 1013 of the crown 1008 and is at least partially defined by the upper region 1011 and the lower region 1013 of the crown 1008. The cavity 1030 has a top wall 1017, a rear wall 1019, and a bottom ramp 1021. A first bending point 1082 is disposed between the top wall 1017 and the rear wall 1019 of the cavity 1030. A second bending point 1086 is disposed between the rear wall 1019 and the bottom ramp 1021 of the cavity 1030.

[0085] In some embodiments, the height of the rear wall 1019, measured from the first bending point 1082 to the second bending point 1086, can be from about 0.010 inches (0.25 mm) to about 0.138 inches (3.5 mm), or from about 0.010 inches (0.25 mm) to about 0.059 inches (1.5 mm). For example, the height of the rear wall 1019 can be about 0.01 inches (0.25 mm), 0.02 inches (0.5 mm), 0.03 inches (0.75 mm), 0.04 inches (1.0 mm), 0.05 inches (1.25 mm), 0.06 inches (1.5 mm), 0.07 inches (1.75 mm), 0.08 inches (2.0 mm), 0.09 inches (2.25 mm), 0.10 inches (2.5 mm), 0.11 inches (2.75 mm), 0.12 inches (3.0 mm), 0.13 inches (3.25 mm), or 0.14 inches (3.5 mm). In many embodiments, the apex of the top wall 1017 can be below the apex of the top rail 1015, from about 0.125 inches (0.318 cm) to about 1.25 inches (3.18 cm), or from about 0.25 inches (0.635 cm) to about 1.25 inches (3.18 cm). For example, the apex of the top wall 1017 can be below the top rail 1015, about 0.125 inches (0.318 cm), 0.25 inches (0.635 cm), 0.375 inches (0.953 cm), 0.5 inches (1.27 cm), 0.625 inches (1.59 cm), 0.75 inches (1.91 cm), 0.825 inches (2.10 cm), 1.0 inches (2.54 cm), 1.125 inches (2.88 cm), or 1.25 inches (3.18 cm).

[0086] In many embodiments, the rear wall 1019 of the cavity 1030 can be substantially parallel to the hitting surface 1012. In other embodiments, the rear wall 1019 is not substantially parallel to the hitting surface 1012. In many embodiments, the top wall 1017 of the cavity is inclined toward the hitting surface 1012 when moving toward the first bending point 1082. This arrangement of the top wall 1017 creates a buckling point or hinge point or plastic hinge that directs the impact stress toward the cavity 1030, allowing the deflection of the hitting surface 1012 during impact to increase.

[0087] The lower region 1013 of the crown 1008 has a bottom slope 1021 of the cavity 1030. In many embodiments, the second bending point 1086 can be adjacent to the bottom slope 1021, below the apex of the top rail 1015, at least about 0.25 inches (0.635 cm) to about 2.0 inches (5.08 cm), or about 0.5 inches (1.27 cm) to about 1.5 inches (3.81 cm). For example, the second bending point 1086 can be below the apex of the top rail 1015, at least about 0.25 inches (0.635 cm), 0.5 inches (1.27 cm), 0.75 inches (1.91 cm), 1.0 inch (2.53 cm), 1.25 inches (3.18 cm), 1.5 inches (3.81 cm), 1.75 inches (4.45 cm) or 2.0 inches (5.08 cm). In some embodiments, the maximum height of the bottom slope, measured from the sole 1006 of the club head 1000 to the second bending point 1086, can be above the lowest point of the sole 1006, at least about 0.25 inches (about 0.635 cm) to about 3 inches (about 7.62 cm), or about 0.50 inches (1.27 cm) to about 2 inches (5.08 cm). For example, the second bending point 1086 can be above the lowest point of the sole, at least about 0.25 inches (0.635 cm), 0.375 inches (0.953 cm), 0.5 inches (1.27 cm), 0.625 inches (1.59 cm), 0.75 inches (1.91 cm), 0.825 inches (2.10 cm), 1.0 inch (2.54 cm), 1.125 inches (2.88 cm), 1.25 inches (3.18 cm), 1.375 inches (3.49 cm), 1.5 inches (3.81 cm), 1.625 inches (4.12 cm), 1.75 inches (4.45 cm), 1.875 inches (4.76 cm), 2.0 inches (5.08 cm), 2.125 inches (5.40 cm), 2.25 inches (5.71 cm), 2.375 inches (6.03 cm), 2.5 inches (6.35 cm), 2.625 inches (6.67 cm), 2.75 inches (7.00 cm), 2.875 inches (7.30 cm), or 3.0 inches (7.62 cm).

[0088] Cavity 1030 further has at least one channel 1039 (FIG. 10). In many embodiments, channel 1039 extends from heel region 1002 to toe region 1004. Channel width 1032 (FIG. 12) can be substantially constant through channel 1039. In some embodiments, channel width 1032 (FIG. 12) can be from about 0.008 inches (0.2 mm) to about 1 inch (25 mm), or from about 0.008 inches (0.2 mm) to about 0.31 inches (8 mm). For example, channel width 1032 can be about 0.008 inches (0.2 mm), 0.016 inches (0.4 mm), 0.024 inches (0.6 mm), 0.031 inches (0.8 mm), 0.039 inches (1.0 mm), 0.079 inches (2 mm), 0.12 inches (3 mm), 0.16 inches (4 mm), 0.20 inches (5 mm), 0.24 inches (6 mm), 0.28 inches (7 mm), 0.31 inches (8 mm), 0.39 inches (10 mm), 0.59 inches (15 mm), 0.79 inches (20 mm), or 0.98 inches (25 mm). In other embodiments, the channel toe region width of channel 1039 is smaller than the channel heel region of the channel. In other embodiments, the channel heel region width is smaller than the channel toe region width. In other embodiments, the channel center region width of channel 1039 can be made smaller than at least one of the channel heel region width or the channel toe region width. In other embodiments, the channel center region width can be made smaller than at least one of the channel heel region width or the channel toe region width. In some embodiments, channel 1039 is symmetric. In other embodiments, channel 1039 is asymmetric. In other embodiments, channel 1039 can further have at least two partial channels. In some embodiments, channel 1039 can have a series of partial channels blocked by one or more bridges. In some embodiments, one or more bridges can be made substantially the same as the thickness of the upper region 1011 of crown 1008.

[0089] As shown herein, the channel width 1032 is capable of absorbing stress from the hitting face 1012 upon impact. A golf club head having a channel width narrower than the channel widths described herein (e.g., a golf club head having an unclear cavity) has less stress that can be absorbed from the hitting face upon impact (due to less material in the upper region 1011 of the crown 1008), and thus, the hitting face experiences less deflection than the golf club head 1000 described herein.

[0090] In many embodiments, the cavity 1030 further has a back cavity angle 1035. The back cavity angle is measured between the top wall 1017 and the rear wall 1019 of the cavity 1030. In many embodiments, the back cavity angle 1035 can be from about 70 degrees to about 110 degrees. In some embodiments, the back cavity angle 1035 can be from about 80 degrees to about 100 degrees. In some embodiments, the back cavity angle 1035 is about 70, 75, 80, 85, 90, 95, 100, or 110 degrees. In many embodiments, the back cavity angle 1035 provides a buckling point or a plastic hinge or a target hinge at the top rail hinge point 1070 when the golf club head 1000 impacts a golf ball. In some embodiments, the wall thickness at the top rail hinge point 1070 is thinner than that at the top wall 1017 of the cavity 1030.

[0091] FIG. 13 shows a view in which the crown 1008 in the cross section of the golf club head 1000 of FIG. 12 is arranged in parallel to the cavity-less golf club head 1200 along the same cross-sectional line XII-XII as in FIG. 10. In many embodiments, the golf club head 1000 has a loft angle 1040, a crown rail angle 1045, and a face angle 1050. The loft angle 1040 is measured from the top wall 1017 to the back wall 1023 of the upper region 1011. In many embodiments, the loft angle 1040 can be from about 70 degrees to about 110 degrees. In some embodiments, the loft angle 1040 is about 90 degrees. The crown rail angle 1045 is measured from the back wall 1023 of the upper region 1011 to the crown rail 1015. In many embodiments, the crown rail angle 1045 can be from about 35 degrees to about 120 degrees, or from 70 degrees to about 110 degrees. In some embodiments, the crown rail angle 1045 can be about 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, or 120 degrees. The face angle 1050 is measured from the hitting face 1012 to the crown rail 1015. In many embodiments, the face angle 1050 can be from about 70 degrees to about 160 degrees, or from 70 degrees to about 110 degrees. In some embodiments, the face angle 1050 is about 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, or 160 degrees.

[0092] Referring to FIG. 13, in some embodiments, the minimum gap 1090 between the hitting face 1012 and the rear wall 1019 is from about 0.079 inches (2 mm) to about 0.39 inches (10 mm). For example, the minimum gap 1090 between the hitting face 1012 and the rear wall 1019 can be about 0.079 inches (2 mm), 0.16 inches (4 mm), 0.24 inches (6 mm), 0.31 inches (8 mm) or 0.39 inches (10 mm). In some embodiments, the minimum gap 1090 between the hitting face 1012 and the rear wall 1019 is less than about 0.55 inches (14 mm), less than 0.47 inches (12 mm), less than about 0.39 inches (10 mm), less than about 0.31 inches (8 mm), less than about 0.24 inches (6 mm), or less than about 0.16 inches (4 mm). Further, in some embodiments, the maximum gap between the hitting face 1012 and the rear wall 1023 in the upper region 1011 of the golf club head 1000 is greater than the minimum gap 1090. Further, in some embodiments, the maximum gap between the hitting face 1012 and the bottom slope 1021 in the lower region 1013 of the golf club head 1000 is greater than the minimum and maximum gaps in the upper region 1011.

[0093] FIG. 21 shows a cross-sectional view of the golf club head 1000 similar to the cross-section of the golf club head 1000 shown in FIG. 12. The golf club head 1000 has a cavity 1030, an upper region 1011, and a lower region 1013. The upper region 1011 has an upper outer rear wall 1023, the cavity 1030 has a cavity outer wall 1025, and the lower region 1013 has a lower outer wall 1027. In many embodiments, the maximum upper distance 1092 measured vertically from the hitting face 1012 to the rear wall 1023 of the upper region 1011 can be about 0.20 to 0.59 inches (5 to 15 mm). For example, the maximum upper distance 1092 can be about 0.20 inches (5 mm), 0.24 inches (6 mm), 0.28 inches (7 mm), 0.31 inches (8 mm), 0.35 inches (9 mm), 0.39 inches (10 mm), 0.43 inches (11 mm), 0.47 inches (12 mm), 0.51 inches (13 mm), 0.55 inches (14 mm), or 0.59 inches (15 mm). Further, the minimum cavity distance 1094 measured vertically from the hitting face 1012 to the cavity outer wall 1025 can be about 0.16 to 0.47 inches (4 to 12 mm). For example, the minimum cavity distance 1094 can be about 0.16 inches (4 mm), 0.20 inches (5 mm), 0.24 inches (6 mm), 0.28 inches (7 mm), 0.31 inches (8 mm), 0.35 inches (9 mm), 0.39 inches (10 mm), 0.43 inches (11 mm), or 0.47 inches (12 mm). Further, the maximum lower distance 1096 measured vertically from the hitting face 1012 to the lower outer wall 1027 can be about 0.98 to 1.57 inches (25 to 40 mm). For example, the maximum lower distance 1096 can be about 0.98 inches (25 mm), 1.02 inches (26 mm), 1.06 inches (27 mm), 1.10 inches (28 mm), 1.14 inches (29 mm), 1.18 inches (30 mm), 1.22 inches (31 mm), 1.26 inches (32 mm), 1.30 inches (33 mm), 1.34 inches (34 mm), 1.38 inches (35 mm), 1.42 inches (36 mm), 1.46 inches (37 mm), 1.50 inches (38 mm), 1.54 inches (39 mm), or 1.57 inches (40 mm).In many embodiments, the maximum lower distance 1096 is greater than the maximum upper distance 1092, and the maximum upper distance 1092 is greater than the minimum cavity distance 1094.

[0094] In many embodiments, the cavity 1030 can increase the speed of the golf ball more than a golf club head 1200 or other standard golf club head, can reduce the spin speed of a standard hybrid club head, and can increase the launch angle more than standard hybrid and iron club heads. In many embodiments, the shape of the cavity 1035 determines the spring level and the response timing of the golf club head 1000. When a golf ball impacts the hitting face 1012 of the club head 1000 having the cavity 1030, the hitting face 1012 springs back in a drum-like manner, and the crown 1008 bends in a controlled crushing pattern. In many embodiments, the top rail 1015 can absorb more stress over a larger volume space than the top rail of a golf club head without the cavity 1030. The length, depth, and width of the cavity 1030 can be changed. These parameters control how much spring back is provided in the overall design of the club head 1000.

[0095] When impacting a golf ball, the hitting face 1012 can bend inward more at a greater distance than a golf club without the cavity 1030. In some embodiments, the hitting face 1012 has about 10% to about 50% more deflection than the hitting face of a golf club head without the cavity 1030. In some embodiments, the hitting face 1012 has about 5% to about 40%, or about 10% to about 20% more deflection than the hitting face of a golf club head without the cavity 1035. For example, the hitting face 1012 can have about 5%, 10%, 15%, 20%, 25%, 30%, 35%, or 40% more deflection than the hitting face of a golf club head without the cavity 1035. In many embodiments, both the draw distance by the hitting face 1012 due to the hinge and the bending of the cavity 1030 are greater than those of a standard hitting face without a cavity and without a back portion of the club.

[0096] In many embodiments, the clubhead 1000 having the cavity 1030 has greater face deflection because greater buckling occurs along the top rail hinge point 1070 when the golf ball is impacted. However, the cavity 1030 provides a large stress distribution along the top rail hinge point 1070 of the top rail, and the springback force is transmitted from the cavity 1030 and the top rail 1015 to the hitting face 1012. A standard top rail without a cavity does not have this hinge / buckling effect and also does not have a high level of stress absorption over a large volume area of the top rail. Thus, a standard hitting face does not have as much contact and recoil as the hitting face 1012. Further, both the large area of the hitting face 1012 and the top rail 1015 absorb more stress than the same crown area of a standard golf clubhead having a standard top rail and no cavity. In many embodiments, there is more stress along a larger area over the cavity 1030 than in the same area in a standard club without a cavity, but the durability of the clubhead with a cavity and the clubhead without a cavity is the same. By adding a larger spring at the rear end of the club (by the inward slope of the top wall 1017 facing the hitting face 1012), a larger force moves throughout the volume of the structure. Stress is observed over a larger area of the hitting face 1012 and the top rail 1015 of the golf clubhead 1000. Peak stress can be seen in a standard top rail clubhead. However, while more peak stress is seen in the golf clubhead 1000, it is distributed over a large volume of the material. The hinge and bending regions of the golf clubhead 1000 (i.e., the region over the cavity 1030 and the cavity 1030 itself) do not deform unless the stress reaches the critical buckling threshold. The cavity 1030 and its movement can be designed to be below the critical K value of the buckling threshold.

[0097] III. Golf Clubhead Having a Cascade Sole and a Back Cavity In some embodiments, a golf club head having a back cavity further comprises a cascading sole having stepped thin portions. FIG. 14 shows a cross-section of a golf club head 1100 according to an embodiment, which can be similar to the golf club head 1000 (FIG. 10) along the same cross-section line XII-XII as in FIG. 10. Similar to the golf club head 1000 (FIG. 10), the golf club head 1100 has a body 1101. The body 1101 has a hitting face 1112, a sole 1106, and a crown 1108. The hitting face 1112 has a high region 1176, a middle region 1174, and a low region 1172. The crown 1108 has an upper region 1111 and a lower region 1113. The upper region 1111 has a top rail 1115. In many embodiments, the cavity 1130 is disposed below the top rail 1115. The golf club head 1100 further has a cascading sole 1310 similar to the inner diameter transition portion 310 (FIG. 3). The inner diameter transition portion 1310 can have a first step 1315 of a first thickness, a second step 1317 of a second thickness, and a step transition region 1316. In some embodiments, the cascading sole 1310 can further impart more flexibility to the top rail 1115. In many embodiments, the back cavity combined with the cascading sole imparts a greater spring effect to the hitting face. In some embodiments, the back cavity having the cascading sole allows about 3% to 5% more energy for the deflection of the hitting face. The cascading sole 1310 can have any number of steps of two or more. For example, the cascading sole 1310 can have 2, 3, 4, 5, 6, or 7 steps.

[0098] A golf club head 1100 having a cascade sole and a back cavity can impart a greater recoil force to the hitting face than a golf club head having only a cascade sole or a back cavity. This is due to the increased recoil force combined from both the inner diameter transition portion and the back cavity as described above. The increased recoil force on the hitting face increases the deflection, which increases the impact force applied to the golf ball, thereby increasing the speed of the golf ball. In some embodiments, the golf club head 1100 having both the cavity 1130 and the inner diameter transition portion 1310 can increase the ball speed, increase the launch angle, and provide good distance control. In various embodiments, the golf club head 1100 can increase the ball speed by about 1% to about 4%. In various embodiments, the golf club head 1100 can increase the ball speed by about 1%, 2%, 3% or 4%. In many embodiments, the golf club head 1100 increases the ball speed more when the golf ball impacts in the high region 1176 of the hitting face. In some embodiments, the golf club head 1100 can increase the launch angle by about 0.5 degrees to about 1.1 degrees. In some embodiments, the golf club head 1100 can increase the launch angle by about 0.5 degrees, 0.6 degrees, 0.7 degrees, 0.8 degrees, 0.9 degrees, 1.0 degrees or 1.1 degrees.

[0099] An embodiment of a golf club head 1100 having a cascade sole and a back cavity was tested. Overall, the cavity-back golf club head showed an increase in golf ball speed and launch angle when compared to a control golf club head lacking a cascade sole and a back cavity. The cavity-back golf club head showed an increase in golf ball speed and launch angle for any contact position on the hitting face due to the combined spring effect from the combination of the cascade sole 1310 (FIG. 14) and the cavity 1130 (FIG. 14). In some embodiments, a greater increase in golf ball speed and launch angle was observed for contact at the high portion of the hitting face (e.g., high region 1076 (FIG. 12) or high region 1176 (FIG. 14)) due in part to the spring effect of the cavity 1130 (FIG. 14). FIGS. 19-20 show the results of testing an embodiment of a golf club head 1100 (cavity-back golf club head) compared to a standard iron-type golf club head (control golf club head) having a loft angle similar to that of a closed-back design and a cavity-back golf club head. FIG. 19 shows the increase in golf ball speed of the cavity-back golf club head compared to the control golf club head when the golf ball impacts the high portion of the hitting face, and FIG. 20 shows the increase in launch angle of the cavity-back golf club head compared to the control golf club head when the golf ball impacts the high portion of the hitting face.

[0100] In particular, FIG. 19 shows that when compared to a control golf club head, the golf ball speed of the cavity-back golf club head increases by approximately 1.9% (or approximately 2.5 mph) when the golf ball impacts the hitting face in the high toe region, by approximately 2.1% (or approximately 2.8 mph, or approximately 4.5 kph) when the golf ball impacts the hitting face in the high center region, and by approximately 1.5% (or approximately 2.0 mph, or approximately 3.2 kph) when the golf ball impacts the hitting face in the high heel region (for all of the cavity-back golf club heads). When the golf ball impacts the hitting face in the high toe region of the control golf club head, the speed of the golf ball is approximately 132.5 mph (213.2 kph), while when the golf ball impacts the hitting face in the high toe region of the cavity-back golf club head, the golf ball reaches approximately 135.0 mph (217.3 kph). When the golf ball impacts the hitting face in the high center region of the control golf club head, the speed of the golf ball is approximately 133.4 mph (214.7 kph), while when the golf ball impacts the hitting face in the high center region of the cavity-back golf club head, the golf ball reaches approximately 136.2 mph (219.2 kph). When the golf ball impacts the hitting face in the high heel region of the control golf club head, the speed of the golf ball is approximately 134.0 mph (215.7 kph), while when the golf ball impacts the hitting face in the high heel region of the cavity-back golf club head, the golf ball reaches approximately 136.0 mph (218.9 kph).

[0101] FIG. 20 shows that when compared to a control golf club head, the launch angle of the cavity-back golf club head increases by approximately 4.2% (or approximately 0.6 degrees) when the golf ball impacts the hitting face in the high toe region, by approximately 4.8% (or approximately 0.7 degrees) when the golf ball impacts the hitting face in the high center region, and by approximately 6.4% (or approximately 0.9 degrees) when the golf ball impacts the hitting face in the high heel region (for all of the cavity-back golf club heads). When the golf ball impacts the hitting face in the high toe region of the control golf club head, the launch angle is approximately 14.4 degrees, while when the golf ball impacts the hitting face in the high toe region of the cavity-back golf club head, the launch angle is approximately 15.0 degrees. When the golf ball impacts the hitting face in the high center region of the control golf club head, the launch angle is approximately 14.5 degrees, while when the golf ball impacts the hitting face in the high center region of the cavity-back golf club head, the launch angle is approximately 15.2 degrees. When the golf ball impacts the hitting face in the high heel region of the control golf club head, the launch angle is approximately 14.1 degrees, while when the golf ball impacts the hitting face in the high heel region of the cavity-back golf club head, the launch angle is approximately 15.0 degrees.

[0102] FIG. 17 shows a method 1700 of manufacturing a golf club head. Method 1700 includes preparing a body (block 1705). Preparing the body at block 1705 comprises providing a body having a hitting face, a heel region, a toe region opposite the heel region, a sole, and a crown. In many embodiments, the crown has an upper region and a lower region. In some embodiments, the upper region has a top rail. In many embodiments, a cavity is disposed below the top rail and above the lower region of the crown (block 1710). In some embodiments, the cavity is at least partially defined by the upper and lower regions of the crown. The cavity has a top wall, a rear wall adjacent to the top wall, a bottom ramp adjacent to the rear wall, a back cavity angle measured between the top wall and the rear wall of the cavity, and at least one channel.

[0103] In some embodiments, method 1700 further includes providing an insert facing the toe region in the lower region of the crown. In some embodiments, the insert is similar to insert 1062 (FIG. 10).

[0104] In some embodiments, at block 1705, provide a body further comprising a body having a cascading sole. The cascading sole includes an inner diameter transition portion from the hitting face to the sole. In many embodiments, the inner diameter transition region can be similar to the inner diameter transition portion or cascading sole 1310 (FIG. 14). In some embodiments, the inner diameter transition region includes a first stage having a first thickness, a second stage having a second thickness thinner than the first thickness, and a step transition region between the first stage and the second stage.

[0105] IV. Golf Club with Cascading Sole and Back Cavity Turning to FIG. 15, FIG. 15 shows a golf club 1500 comprising a golf club head 1500 and a shaft 1590 coupled to the golf club head 1500. In some embodiments, the golf club head 15000 of the golf club 1500 comprises a hybrid type golf club head. In other embodiments, the golf club head 1500 can be an iron type golf club head or a fairway wood type golf club head. In many embodiments, the golf club head 1500 can be similar to the golf club head 100 or golf club head 1000 (FIG. 10). The golf club head 1500 can be a hollow body and has a hitting face 1512, a heel region 1502, a toe region 1504 opposite the heel region 1502, a sole 1506, and a crown 1508. The crown 1508 has an upper region 1511 and a lower region 1513. The upper region 1511 has a top rail 1515. The golf club head 1500 further comprises a cavity 1530 disposed below the top rail 1515 and above the lower region 1513 of the crown 1508.

[0106] FIG. 16 shows a cross-section of the golf club head 1500 along the cross-section line XVI-XVI of FIG. 15 according to one embodiment. In some embodiments, the cavity 1530 can at least partially define an upper region 1511 and a lower region 1513. In many embodiments, the cavity 1530 has a top wall 1517, a rear wall 1519, a bottom slope 1521, a back cavity angle 1535 measured between the top wall 1517 and the rear wall 1519, and at least one channel 1539. In some embodiments, the apex of the top wall 1517 is below the apex of the top rail 1515, from about 0.25 inches to about 1.25 inches. In some embodiments, the apex of the top wall 1517 is below the apex of the top rail 1515, about 0.375 inches. In some embodiments, the bottom slope 1521 can be at least about 0.50 inches to about 2 inches from the lower apex of the top rail 1515. In many embodiments, the back cavity angle 1535 can be from about 70 degrees to about 110 degrees. In some embodiments, the back cavity angle 1535 can be about 90 degrees.

[0107] In many embodiments, the upper region 1511 includes the top of the cavity and the lower region of the crown having the bottom slope of the cavity. In some embodiments, the upper region 1511 further includes a rear wall 1523 adjacent to the top wall 1517 of the cavity 1530 and a back angle 1540 measured between the top wall 1517 of the cavity 1530 and the rear wall 1523 of the upper region 1511. In many embodiments, the back angle 1540 is from about 70 degrees to about 110 degrees.

[0108] In other embodiments, the golf club head can have a hosel. The hosel can have a hosel notch. The hosel notch can be in the iron-like range of loft and can be arranged to adjust the lie angle. Although not shown in FIG. 16, the golf club head 1500 can further have a cascade sole or an inner diameter transition in the sole.

[0109] The golf club head having the energy storage characteristics discussed in this specification can be implemented in various embodiments, and the foregoing discussion of these embodiments does not necessarily represent a complete description of all possible embodiments. Rather, the detailed description of the drawings and the drawings themselves can disclose at least one preferred embodiment of a golf club head having energy storage characteristics and can disclose other embodiments of a golf club head provided with a stepped inner thin portion.

[0110] Clause 1. A golf club head comprising a hitting face, a heel region, a toe region opposite the heel region, a sole, a crown, and a body having an inner diameter transition portion from the hitting face to at least one of the sole or the crown, wherein the inner diameter transition portion is not visible from the outside of the golf club head and comprises a first step, a second step, and a step transition region between the first step and the second step.

[0111] Clause 2. The golf club head according to Clause 1, wherein the first step has a first substantially constant thickness and the second step has a second substantially constant thickness different from the first substantially constant thickness.

[0112] Clause 3. The golf club head according to Clause 1, wherein the step transition region has a linearly graded thickness.

[0113] Clause 4. The golf club head according to Clause 1, wherein the step transition region has a step of approximately 90 degrees.

[0114] Clause 5. The golf club head according to Clause 1, wherein the inner diameter transition region further comprises a third step having a third thickness thinner than the first thickness of the first step and the second thickness of the second step.

[0115] Clause 6. The golf club head according to Clause 1, wherein the first step length of the first step is substantially equal to the second step length of the second step, and the first and second step lengths are measured from the hitting face toward the rear of the golf club head.

[0116] Clause 7. The golf club head according to Clause 1, wherein the first stage is longer than the second stage when measured from the hitting face to the rear of the golf club head.

[0117] Clause 8. The golf club head according to Clause 3, wherein the third stage is longer than the second stage when measured from the hitting face to the rear of the golf club head.

[0118] Clause 9. The golf club head according to Clause 1, wherein the body further has an inner weight pad on the sole.

[0119] Clause 10. The golf club head according to Clause 9, wherein the inner weight pad is thicker than the first stage of the inner diameter transition portion.

[0120] Clause 11. The golf club head according to Clause 1, wherein the body further has an inner rib on the sole that is substantially parallel to the hitting face, and the inner rib thickness of the inner rib is thicker than the final stage of the inner diameter transition portion.

[0121] Clause 12. The golf club head according to Clause 1, wherein the golf club head has a driver golf club head.

[0122] Clause 13. The golf club head according to Clause 1, wherein the golf club head has a fairway wood golf club head.

[0123] Clause 14. The golf club head according to Clause 1, wherein the golf club head has a hybrid golf club head.

[0124] Clause 15. The golf club head according to Clause 1, wherein the golf club head has an iron golf club head.

[0125] Clause 16. Each of the first and second transition regions has a first and a second arcuate surface, the first arcuate surface having a first radius of curvature and the second arcuate surface having a second radius of curvature, the golf club according to Clause 1.

[0126] Clause 17. The first and second radii of curvature of the first transition region are at least twice the difference between the first thickness and the second thickness of the first and second stages respectively, and the first and second radii of curvature of the second transition region are at least twice the difference between the second thickness and the third thickness of the second and third stages respectively, the golf club according to Clause 10.

[0127] Clause 18. The first and second radii of curvature of the first transition region are approximately 6.5 times the difference between the first thickness and the second thickness of the first and second stages respectively, and the first and second radii of curvature of the second transition region are approximately 6.5 times the difference between the second thickness and the third thickness of the second and third stages respectively, the golf club according to Clause 16.

[0128] Clause 19. The first stage has a thickness of from about 0.030 inches to about 0.060 inches, the second stage has a thickness of from about 0.020 inches to about 0.050 inches, and the third stage has a thickness of from about 0.010 inches to about 0.040 inches, the golf club head according to Clause 5.

[0129] Clause 20. The first stage has a thickness of from about 0.035 inches to about 0.065 inches, the second stage has a thickness of from about 0.025 inches to about 0.055 inches, and the third stage has a thickness of from about 0.015 inches to about 0.045 inches, the golf club head according to Clause 5.

[0130] Clause 21. The first stage has a thickness of from about 0.050 inches to about 0.080 inches, the second stage has a thickness of from about 0.040 inches to about 0.070 inches, and the third stage has a thickness of from about 0.030 inches to about 0.060 inches, the golf club head according to Clause 5.

[0131] Clause 22. The golf club head according to clause 5, wherein the first stage has a thickness of from about 0.055 inches to about 0.085 inches, the second stage has a thickness of from about 0.045 inches to about 0.075 inches, and the third stage has a thickness of from about 0.030 inches to about 0.060 inches.

[0132] Clause 23. The golf club head according to clause 1, wherein the inner diameter transition region has a plastic hinge.

[0133] Clause 24. Further, it includes a cavity having a top wall, a rear wall, a bottom slope, a back cavity angle measured between the top and rear walls of the cavity, and at least one channel, the cavity being disposed below the top rail of the crown and above the lower region of the crown, and at least partially defined by the upper region and the lower region of the crown, the golf club head according to clause 1.

[0134] Clause 25. Further, it includes a first crown thickness located at the front end of the club head on the back of the hitting face or the inner diameter transition portion, and a second crown thickness located towards the rear of the club head behind the first crown thickness, the first crown thickness being thicker than the second crown thickness, the golf club head according to clause 1.

[0135] Clause 26. A golf club comprising a golf club head having a hitting face, a heel region, a toe region opposite the heel region, a sole, a crown, and an inner diameter transition portion from the hitting face to at least one of the sole or the crown, and a shaft connected to the golf club head, wherein the inner diameter transition portion is not visible from the outside of the golf club head and includes a first stage, a second stage, and a step transition region between the first stage and the second stage, the golf club.

[0136] Clause 27. The golf club according to clause 26, wherein the first stage has a first substantially constant thickness and the second stage has a second substantially constant thickness different from the first substantially constant thickness.

[0137] Clause 28. The stepped transition region has a linearly thickened slope, and the golf club according to clause 26.

[0138] Clause 29. The stepped transition region has a step of approximately 90 degrees, and the golf club according to clause 26.

[0139] Clause 30. The inner diameter transition region further includes a third stage having a third thickness that is thinner than the first thickness of the first stage and the second thickness of the second stage, and the golf club according to clause 26.

[0140] Clause 31. The length of the first stage of the first stage is substantially equal to the length of the second stage of the second stage, and the first and second stage lengths are measured from the hitting surface toward the rear of the golf club head, and the golf club according to clause 26.

[0141] Clause 32. The first stage is longer than the second stage when measured from the hitting surface toward the rear of the golf club head, and the golf club according to clause 26.

[0142] Clause 33. The third stage is longer than the second stage from the hitting surface toward the rear of the golf club head, and the golf club according to clause 30.

[0143] Clause 34. The golf club head further has an inner weight pad on the sole, and the golf club according to clause 26.

[0144] Clause 35. The inner weight pad is thicker than the first stage of the inner diameter transition portion, and the golf club according to clause 34.

[0145] Clause 36. The golf club head further has an inner rib on the sole that is substantially parallel to the hitting surface, and the inner rib thickness of the inner rib is thicker than the final stage of the inner diameter transition portion, and the golf club according to clause 26.

[0146] Clause 37. Each of the first and second transition regions has a first and a second arcuate surface, the first arcuate surface has a first radius of curvature, and the second arcuate surface has a second radius of curvature, the golf club according to Clause 30.

[0147] Clause 38. The first and second radii of curvature of the first transition region are each at least twice the difference between the first thickness and the second thickness of the first and second stages, and the first and second radii of curvature of the second transition region are each at least twice the difference between the second thickness and the third thickness of the second and third stages, the golf club according to Clause 37.

[0148] Clause 39. The first stage has a thickness of from about 0.035 inches to about 0.065 inches, the second stage has a thickness of from about 0.025 inches to about 0.055 inches, and the third stage has a thickness of from about 0.015 inches to about 0.045 inches, the golf club according to Clause 30.

[0149] Clause 40. The first stage has a thickness of from about 0.050 inches to about 0.080 inches, the second stage has a thickness of from about 0.040 inches to about 0.070 inches, and the third stage has a thickness of from about 0.030 inches to about 0.060 inches, the golf club according to Clause 30.

[0150] Clause 41. The first stage has a thickness of from about 0.055 inches to about 0.085 inches, the second stage has a thickness of from about 0.045 inches to about 0.075 inches, and the third stage has a thickness of from about 0.030 inches to about 0.060 inches, the golf club according to Clause 30.

[0151] Clause 42. The inner diameter transition region has a plastic hinge, the golf club according to Clause 26.

[0152] Clause 43. Further, there is provided a cavity, the cavity having a top wall, a rear wall, a bottom slope, a back cavity angle measured between the top and rear walls of the cavity, and at least one channel, the cavity being disposed below the top rail of the crown, above the lower region of the crown, and at least partially defined by the upper region and the lower region of the crown, the golf club according to clause 26.

[0153] Clause 44. A method of manufacturing a golf club head including providing a body having a hitting face, a heel region, a toe region opposite the heel region, a sole, and a crown, and providing an inner diameter transition from the hitting face to at least one of the sole or the crown, the inner diameter transition not being visible from the exterior of the golf club head and including a first stage having a first thickness, a second stage having a second thickness thinner than the first thickness, and a step transition region between the first stage and the second stage, the method of manufacturing the golf club head.

[0154] Clause 45. The method of manufacturing the golf club head according to clause 44, wherein the first thickness is substantially constant and the second thickness is substantially constant and different from the first thickness.

[0155] Clause 46. The method of manufacturing the golf club head according to clause 44, wherein the inner diameter transition region further includes a third stage having a third thickness thinner than the first thickness of the first stage and the second thickness of the second stage.

[0156] The substitution of one or more claim elements constitutes a rearrangement and not a patching. Further, advantages over the problem, other advantages, and solutions have been described in connection with specific embodiments. However, an advantage over the problem, other advantages, and solutions, and any one or more elements that cause or make apparent any advantage, advantage, or solution, do not constitute a material, essential, or essential feature or element of any or all of the claim elements unless such advantage, advantage, solution, or element is explicitly stated in such claims.

[0157] The rules for golf are sometimes changed (for example, new rules may be applied by golf standard organizations and / or regulatory bodies such as the United States Golf Association (USGA), the Royal & Ancient Golf Club of St Andrews (R&A), etc., or old rules may be abolished or changed). Therefore, the golf supplies related to the devices, methods, and products described herein may or may not conform to the golf rules at any given time. Accordingly, the golf supplies related to the devices, methods, and products described herein may be published, sold, and / or sold as conforming or non-conforming golf supplies. The devices, methods, and products described herein are not limited in this regard.

[0158] The above embodiments are described in connection with driver-type golf clubs, but the devices, methods, and products described herein may be applicable to other types of golf clubs such as fairway-type golf clubs, hybrid-type golf clubs, iron-type golf clubs, wedge-type golf clubs, or putter-type golf clubs. On the other hand, the devices, methods, and products described herein may also be applicable to other types of sports equipment such as hockey sticks, tennis rackets, fishing rods, ski stocks, etc.

[0159] Furthermore, the embodiments and limitations described herein are not provided to the public under the doctrine of disclosure if the embodiments and / or limitations are (1) not expressly claimed in the claims and (2) equivalent or potentially equivalent to the recited elements and / or limitations in the claims under the doctrine of equivalents.

Claims

1. An iron-type golf club head comprising a hollow body defining an enclosed internal cavity, said hollow body having a striking face, a hosel having a hosel notch, a heel region, a toe region opposite said heel region, a sole, and a crown, said crown having an upper region of said crown with a top rail, a lower region of said crown, and a tungsten insert provided in said lower region of said crown and facing said toe region, said striking face, said crown, said sole, said heel region, and said toe region defining said hollow body, a cavity being disposed on an outer surface of said hollow body, under said top rail, over said lower region of said crown, and at least partially defined by said upper region and said lower region of said crown, said cavity having a top wall, a rear wall, said top wall and said rear wall of said cavity being provided in said upper region of said crown and defining a part of said hollow body, said rear wall, a first bending point located between said top wall and said rear wall, said rear wall of said cavity being parallel to said striking face, said first bending point, a bottom slope, a back cavity angle measured between said top wall and said rear wall of said cavity, and at least one channel, said at least one channel having at least two partial channels, each of said partial channels being blocked from other partial channels by one or more bridges, a channel width of a channel central region of said at least one channel being smaller than at least one of a channel heel region width or a channel toe region width of said channel, said upper region of said crown having an upper region thickness, said lower region of said crown having a lower region thickness, said at least one bridge having a bridge thickness, said bridge thickness being the same as said upper region thickness, said top wall being inclined toward said striking face in a direction toward said first bending point, said hollow body further comprising a cascading sole, said cascading sole comprising a first step having a first thickness, a second step having a second thickness different from said first thickness, and a step transition region. ​ The upper region of the crown includes an upper outer rear wall. The cavity further includes a cavity outer wall. The lower region of the crown includes a lower outer wall. The maximum upper distance is measured vertically from the hitting face to the upper outer rear wall of the upper region. The minimum cavity distance is measured vertically from the hitting face to the cavity outer wall. The maximum lower distance is measured vertically from the hitting face to the lower outer wall. The maximum lower distance is greater than the maximum upper distance. The maximum upper distance is greater than the minimum cavity distance. An iron-type golf club head.

2. The upper region of the crown has the top wall and the rear wall of the cavity. The lower region of the crown has the bottom slope of the cavity. The iron-type golf club head according to claim 1.

3. The back cavity angle is from 70 degrees to 110 degrees. The iron-type golf club head according to claim 1 or 2.

4. The back cavity angle is from 80 degrees to 110 degrees. The iron-type golf club head according to any one of claims 1 to 3.

5. The upper region of the crown further includes a rear wall adjacent to the top wall of the cavity, and a rear angle measured between the top wall of the cavity and the rear wall of the upper region of the crown. The iron-type golf club head according to any one of claims 1 to 4.

6. The rear angle is from 70 degrees to 110 degrees. The iron-type golf club head according to claim 5.

7. The apex of the top wall is located below the apex of the top rail, from 0.25 inches (0.635 cm) to 1.25 inches (3.18 cm). The iron-type golf club head according to any one of claims 1 to 6.

8. The second bending point is located below the apex of the top rail, from at least 0.5 inches (1.27 cm) to 1.5 inches (3.81 cm). The iron-type golf club head according to claim 7.

9. The second bending point is located above the lowest point of the sole, from 0.5 inches (1.27 cm) to 2 inches (5.08 cm). The iron-type golf club head according to claim 8.

10. The maximum upper distance is in the range of 5 to 15 mm, The minimum cavity distance is in the range of 4 to 12 mm, The maximum lower distance is in the range of 25 to 40 mm, the iron-type golf club head according to any one of claims 1 to 9.

11. The channel width of the at least one channel is within the range of 0.2 mm to 25 mm, the iron-type golf club head according to any one of claims 1 to 9.

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