Golf club head

Abstract

To move a center of gravity closer to a place where a golf ball is likely to be struck and provide forgiveness on off-center hits.SOLUTION: A golf club head 100 includes a loft of 20 to 54 degrees, and a body including a top portion 130, a sole portion 140 on an opposite side of the top portion, a heel portion 120, a toe portion 110 on an opposite side of the heel portion, and a hosel portion 150 extending from the heel portion. The hosel portion includes a hosel bore with an open end for receiving a golf club shaft, a support surface to support the golf club shaft, and an auxiliary recess part extending in a sole direction from the support surface. The auxiliary recess includes volume of 2 cm3 to 3.5 cm3. The golf club head further includes a striking face 160 which defines a virtual face plane and has a face center 164, a virtual vertical center plane 166 which is perpendicular to the virtual face plane and extends through the face center, and a center 170 of gravity separated by 5 mm or less from the virtual vertical center plane.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates generally to the field of golf clubs, and more particularly to golf club heads having an insert in at least a hosel portion of the club head.

[0002] The goal of golf club head design is to align the club head's center of gravity with the location on the striking face that is most likely to make contact with the golf ball during the swing, thereby improving shot accuracy and transferring as much of the energy from the golfer's swing as possible to the golf ball at impact, resulting in a favorable golf shot. DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0003] However, this goal is often difficult to achieve within the constraints of a given mass budget. In some instances, perimeter weighting can be added to an iron or wedge type golf club head to increase the moment of inertia, thereby adding "forgiveness" on off-center hits. However, such a feature can adversely affect the location of the sweet spot. Thus, a need exists for a design that discretely shifts weight from one portion of the club head to another to move the center of gravity closer to where the golf ball is likely to be struck, while also providing forgiveness on off-center hits.

[0004] A golf club head according to one or more embodiments of the present disclosure includes a loft between 20° and 54° when placed in a reference position, and a body, the body including a top portion, a sole portion opposite the top portion, a heel portion, a toe portion opposite the heel portion, and a hosel portion extending from the heel portion. The hosel portion includes a hosel bore having an open end for receiving a golf club shaft and a support surface configured to support the golf club shaft, and an auxiliary recess extending in a sole direction from the support surface, the auxiliary recess having a volume between 2 cubic centimeters and 3.5 cubic centimeters. The golf club head further includes a striking face defining an imaginary face plane and having a face center, an imaginary vertical center plane perpendicular to the imaginary face plane and extending through the face center, and a center of gravity within 5 mm of the imaginary vertical center plane.

[0005] A golf club headset according to one or more embodiments of the present disclosure includes a first golf club head. When placed in a reference position, the first golf club head includes a first loft between 30° and 54°, and a first body, the first body including a first top portion, a first sole portion opposite the first top portion, a first heel portion, a first toe portion opposite the first heel portion, and a first hosel portion extending from the first heel portion. The first hosel portion includes a first hosel bore having a first open end for receiving a golf club shaft and a first support surface configured to support the golf club shaft, and an auxiliary recess extending in a sole direction from the support surface, the auxiliary recess having a volume greater than 2.25 cubic centimeters. The set includes a second golf club head. The second golf club head includes a second loft less than 30° and a second body including a second top portion, a second sole portion opposite the second top portion, a second heel portion, a second toe portion opposite the second heel portion, and a second hosel portion extending from the second heel portion, the second hosel portion including a second hosel bore having a second open end for receiving a golf club shaft, a second support surface configured to support the golf club shaft, and a second bore extending from the support surface in a sole direction, the second bore having a volume less than 1 cubic centimeter.

[0006] A method of forming an interrelated set of golf club heads includes providing a first golf club head, the first golf club head including a first striking face, a first hosel portion including a first hosel bore having a first open end for receiving a golf club shaft and a first support surface configured to support the golf club shaft, and a secondary recess extending in a sole direction from the first support surface, the secondary recess having a volume greater than 2.25 cubic centimeters; applying a coating to at least the first striking face of the first golf club head; and applying a first media blast including aluminum oxide having a grit between 180 and 120 to the first striking face. The method further includes providing a second golf club head, the second golf club head including a second striking face, a second hosel portion including a second hosel bore having a second open end for receiving a golf club shaft and a second support surface configured to support the golf club shaft, and a second bore extending in a sole direction from the second support surface, the second bore having a volume of less than one cubic centimeter; applying a coating to at least the second striking face of the second golf club head; and applying a second media blast to the second striking face, the second media blast comprising a mixture of aluminum oxide and ceramic media, the aluminum oxide having a grit between 180 and 120.

[0007] These and other features and advantages of the golf club head and method of manufacture thereof according to various aspects of the present disclosure will become more apparent upon consideration of the following description, drawings, and appended claims. The description and drawings set forth below are for illustrative purposes only and are not intended to limit the scope of the present invention in any manner. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a front view of an exemplary golf club head according to one or more embodiments of the present disclosure. [Diagram 2] FIG. 2 is a rear view of the example golf club head of FIG. [Diagram 3] FIG. 3 is a heel side elevational view of an exemplary golf club head according to one or more embodiments of the present disclosure. [Figure 4] FIG. 4 is a cross-sectional view of the golf club head taken along line IV-IV in FIG. [Diagram 5] FIG. 5 is a front perspective view of the golf club head of FIG. 3 with the hosel removed. [Figure 6] FIG. 6 is a cross-sectional view of the golf club head taken along line VI-VI in FIG. [Figure 7] FIG. 7 illustrates an exemplary method for manufacturing the golf club head of FIG. [Figure 8] FIG. 8 is an enlarged view of the insert in the golf club head of FIG. [Figure 9] FIG. 9 illustrates the stacking of multiple club heads as part of a method for designing the insert of FIG. [Figure 10] FIG. 10 shows a golf club head resulting from the second step of the method of FIG. [Figure 11] FIG. 11 shows a golf club head resulting from the third step of the method of FIG. [Figure 12] FIG. 12 shows a golf club head resulting from the fourth step of the method of FIG. [Figure 13] FIG. 13 illustrates an example method of manufacturing a golf club head in accordance with one or more aspects of the present disclosure. [Figure 14] FIG. 14 shows a golf club head resulting from the fourth step of the method of FIG. [Figure 15] FIG. 15 is a rear view of a golf club head according to one or more embodiments of the present disclosure. [Figure 16] FIG. 16 is a heel side view of the golf club head of FIG. [Figure 17] 17 is a schematic rear view of the golf club head of FIG. [Figure 18] 18 is a cross-sectional view of the golf club head taken along line XVIII-XVIII in FIG. [Figure 19] 19 is a cross-sectional view of the golf club head taken along line XIX-XIX in FIG. [Figure 20] FIG. 20 is a rear perspective view of a golf club head according to a second embodiment of the present disclosure. [Figure 21] FIG. 21 is a bottom view of the golf club head of FIG. [Figure 22] FIG. 22 is a top view of the golf club head of FIG. [Diagram 23] 23 is a toe side elevational view of the golf club head of FIG. 20. FIG. [Figure 24] 24 is a heel side elevational view of the golf club head of FIG. 20. FIG. [Diagram 25] FIG. 25 is a perspective view of a golf club head according to a third embodiment of the present disclosure. [Figure 26] 26 is a heel side elevational view of the golf club head of FIG. 25. FIG. [Figure 27] 27 is a toe side elevational view of the golf club head of FIG. 25. FIG. [Figure 28] FIG. 28 is a front view of the golf club head of FIG. [Figure 29] 29 is a rear view of the golf club head of FIG. 25. FIG. [Diagram 30] FIG. 30 is a front view of a portfolio of golf club heads according to another embodiment of the present disclosure. [Diagram 31] FIG. 31 shows the characteristics of golf club heads with bounce options #1 and #2. [Figure 32A] FIG. 32A illustrates the properties of a low density insert for a golf club head. [Figure 32B] FIG. 32B illustrates the shape of a low density insert for a golf club head. [Figure 32C] FIG. 32C illustrates the shape of a low density insert for a golf club head. [Fig. 32D] FIG. 32D illustrates the shape of a low density insert for a golf club head. [Figure 32E] FIG. 32E illustrates the shape of a low density insert for a golf club head. [Fig. 32F] FIG. 32F illustrates the shape of a low density insert for a golf club head. [Fig. 32G] FIG. 32G illustrates the shape of a low density insert for a golf club head. [Fig. 32H] FIG. 32H illustrates the shape of a low density insert for a golf club head. [Diagram 33] FIG. 33 is a plot comparing loft and CGy for various golf club heads. [Diagram 34] FIG. 34 is a plot comparing loft and Iyy for various golf club heads. [Diagram 35] FIG. 35 is a plot comparing loft and Iyy / CGy for various golf club heads. [Diagram 36] FIG. 36 is a table listing various parameters of an exemplary golf club head. [Figure 37A] FIG. 37A shows a plot of the SDr values ​​for various golf club heads. [Figure 37B] FIG. 37B shows a plot of the SDr values ​​for various golf club heads. [Figure 38] FIG. 38 illustrates the R2 modeling of an exemplary golf club head. [Figure 39A] FIG. 39A shows plots of Spk / Sk for various golf club heads. [Figure 39B] FIG. 39B shows plots of Svk / Sk for various golf club heads. [Diagram 40] FIG. 40 is a front view of a golf club head according to a fourth embodiment of the present disclosure. [Diagram 41]FIG. 41 is a rear view of the golf club head of FIG. [Diagram 42] FIG. 42 is a front view of another golf club head according to the fourth embodiment of the present disclosure. [Diagram 43] FIG. 43 is a rear view of the golf club head of FIG. [Diagram 44] FIG. 44 is a partial rear view of an illustrative rear striking face of a cavity back club head according to this disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] 1 and 2 is a golf club head 100 according to one or more embodiments of the present disclosure. The body of the golf club head may be bounded by a toe portion 110, a heel portion 120 opposite the toe portion, a top portion 130, and a sole portion 140 opposite the top portion. A hosel portion 150 may extend from the heel portion for securing the club head to a corresponding shaft (not shown), and the hosel portion may define an imaginary central hosel axis 152.

[0010] The club head may further include a striking face 160 at its forward portion. The striking face is a substantially planar exterior portion of the forward portion that generally coincides with the imaginary striking face surface 76 and is positioned to contact a golf ball at a factory-specified loft angle between the striking face surface 76 and the central hosel axis 152. The striking face is formed with surface features that increase traction between the striking face and a struck golf ball to ensure good contact with the ball (e.g., in wet conditions) and may impart some spin to the ball to ensure good contact with the ball, for example, for stability during flight or to better control the resting position of the struck golf ball after it returns to the ground due to backspin. A plurality of substantially parallel horizontal grooves or scorelines 162 may be recessed from the striking face. Various smaller scale features may be considered to form a texture pattern on the striking face.

[0011] The striking face may include a leading edge 161 that defines a junction between a generally planar striking face 160 and the sole portion 140. The leading edge 161 includes a forward-most point 165 (see FIGS. 1 and 3). An imaginary vertical center plane 166 passes through the forward-most point 165 of the leading edge 161. The striking face may include a face center 164. As used herein, face center refers to a point on the striking face of the club head that is midway between the top-most and sole-most extents of the scorelines and passes through the vertical center plane 166. In some embodiments, such as the embodiment shown in FIG. 1, the face center is preferably located midway between the heel-most and toe-most extents of the scorelines. However, in alternative embodiments, the face center is not located midway between the heel-most and toe-most extents of the scorelines. For example, the scorelines may be laterally offset from the leading edge contour, or the scorelines may extend completely to the toe of the striking face. An imaginary vertical center plane 166 perpendicular to the face surface may project through the center of the face in a front-to-rear direction of the club head, and a center of gravity 170 of the golf club head may be spaced from the imaginary vertical center plane. For example, in FIG. 1, the center of gravity may be spaced from the imaginary vertical center plane in a heel direction. The center of gravity may be spaced a distance 172 less than 5 mm from the imaginary vertical center plane, and in a more preferred embodiment, less than 2.5 mm from the imaginary vertical center plane.

[0012] A golf club head is shown in Figure 1 as being in a "reference position." As used herein, "reference position" refers to a position of a golf club head (e.g., the club head of Figure 1) where the sole portion of the club head contacts an imaginary ground plane 10 such that an imaginary central hosel axis 152 of the hosel portion lies in an imaginary vertical hosel plane and the scorelines 162 are oriented horizontally relative to the imaginary ground plane 10. Unless otherwise specified, all club head dimensions described herein are measured with the club head in the reference position.

[0013] The golf club heads of FIGS. 1 and 2 preferably include iron-type club heads, such as wedge-type club heads, and may preferably have a loft angle of 39° or greater. More preferably, the golf club heads may be traditional blade-type club heads, sometimes referred to by certain golfers as "player"-type club heads. As such, and as shown in FIG. 2, the rear portion 180 of the club head may include an upper blade portion 182 and a lower muscle portion 184. The upper blade portion may preferably comprise a substantially planar surface, and thus may preferably lack substantial perimeter weighting features. The muscle portion may project rearwardly from the upper blade portion in a direction perpendicular to the plane of the striking face. The mass of the golf club head is generally concentrated in the muscle portion, such that the center of gravity 170 is located toward the sole of the face center. 2, the golf club head's moment of inertia ("MOI") Izz 186 is measured about an imaginary vertical axis 187 passing through the center of gravity, and the golf club head's MOI Iyy 188 is measured about an imaginary horizontal axis 189 that is parallel to the imaginary ground plane and extends in a heel-to-toe direction, also passing through the center of gravity. As known to those skilled in the art, MOI generally correlates to increasing the club head's natural resistance to rotation about an axis during off-center golf ball impacts.

[0014] Golf club heads according to one or more embodiments of the present disclosure preferably have an internal structure that, compared to other "player" type golf club heads, discretely shifts weight from the lower part of the heel or hosel part to the upper part of the sole / muscle or hosel part, thereby shifting the center of gravity closer to the center of the face, i.e., to the location on the striking face where an experienced golfer is more likely to strike the golf ball, and correspondingly increases the MOI in both the vertical (Izz) and horizontal (Iyy) directions. Exemplary golf club heads having such internal structures are described below. Each of these exemplary club heads can include the body structure described above in connection with FIGS. 1 and 2.

[0015] 4 illustrates a cross-section of a golf club head according to one embodiment of the disclosure taken along line IV-IV of FIG. 3. As shown, the hosel portion 150 of the club head includes a hosel bore 154 that extends from an open top end 156 of the hosel portion to a depth 155 into the hosel portion. The bore may have a top inner diameter 157 and a bottom inner diameter 158, which may be the same or different, and may terminate at the bottom of the hosel bore in a metal shelf 159 that projects inwardly toward an imaginary central hosel axis 152. The hosel portion sidewalls (as well as the remainder of the golf club head body) are preferably made of a first material, such as steel, and / or a metal having a density of 8 g / cm 3 and / or the first component may be formed of a material having a melting point of 1600° C. or less. And, preferably, the minimum thickness 151 of the hosel portion sidewall measured at the bottom of the hosel bore may be sufficient to ensure the structural integrity of the hosel portion without adversely affecting the vibration feedback of the golf shot. For example, this minimum thickness may be 0.5 mm or more, and more preferably 0.75 mm or more.

[0016] Below the bottom of the hosel bore may be an insert 190 that functions as a second, or supplementary, component (i.e., a "supplementary insert"). The supplementary insert may include a substantially cylindrical portion 192 (FIG. 8) having a central axis that is coaxial with the imaginary central hosel axis 152. The insert may also include a heel portion shaped to generally match the heel contour of the golf club head. The insert may be formed of a supplementary material, such as a ceramic, and may preferably have a melting point higher than that of the first component and a density lower than that of the first component. As such, the insert may have a mass of less than about 5 g in the golf club head, and the mass of the insert may be less than 1.5% relative to the overall mass of the golf club head. The insert may be composed of at least 60% by weight aluminum oxide (Al2O3). More specifically, the ceramic insert may be composed of (by weight) 20% SiO2, 10% ZrO2, and 70% Al2O3, although these percentages may vary up to about 10% each. By adjusting the ceramic composition, the material properties of the insert can be tailored to achieve weight distribution goals, such as an increased moment of inertia, a lower and / or more centralized center of gravity location, or a particular vibration frequency during impact. The insert also has the following characteristics: (i) a bond strength of 15 MPa, (ii) a porosity of 40% or less, preferably 30%, (iii) an adsorption of 30%, (iv) a melting point of greater than 2500°C, and (v) a mass of preferably 3 g / cm. 3 Less than 2 g / cm, more preferably 3 It can have the following densities: However, the bond strength, porosity, absorbency and density of the insert, as well as the composition of the insert, can be varied to achieve specific weight distribution goals.

[0017] As shown in Figure 6, which is a cross section of line VI-VI in Figure 5, the insert 190 can extend from the hosel portion to the heel portion of the golf club head. The insert can also affect various MOI values ​​of the golf club head. For example, the vertical MOI Izz is preferably 2500 g cm 2 More preferably, 3000g cm 2 and the horizontal MOI Iyy is 1000g cm 2 It may be possible to exceed .

[0018] 7-12 show an exemplary method 200 for forming the golf club head of FIGS. 3-6. In a first step 210, an insert can be formed, for example, by injection molding. FIG. 8 shows one embodiment of an insert 190 after this first forming step. The insert can be preferably designed by overlapping various club lofts in a computer-aided design ("CAD") program and selecting overlapping areas of those club heads while considering necessary constraints such as minimum steel wall thickness for hosel and / or heel portion integrity. For example, FIG. 9 shows inserts formed in overlapping areas of club heads having lofts of 46°, 54°, and 64°. This design process can ease manufacturing concerns and provide various cost advantages since a new insert does not have to be designed for each loft and sole shape of the golf club head. In one or more embodiments, the minimum steel wall thickness is 0.5 mm or greater, more preferably 0.75 mm or greater.

[0019] In a second step 220 shown in FIG. 7, the golf club head body may then be formed, for example, by lost wax casting, around the insert 190 to at least partially, and preferably substantially completely, encapsulate the insert therein. The result of this step is shown in FIG. 10, where the insert is shown extending through the hosel bore and beyond the opening at the top end 156 of the hosel portion 150, as well as below the metal shelf 159 at the bottom of the hosel bore. The top portion 194 of the insert, i.e., the portion that extends into the hosel bore beyond the opening at the top end of the hosel portion, may then be removed, for example, by machining, in a third step 230 shown in FIG. 7. As shown in FIG. 11, which is the result of this third step, the hosel bore 154 and the top end 156 of the hosel portion may be open to receive a golf club shaft, and the insert 190 may extend below the metal shelf 159 that defines the bottom of the hosel bore. As also shown in FIG. 11, the insert extends to the toe side of the heel-most portion of the scoreline. Preferably, the insert extends at least 1 mm, more preferably at least 2 mm, and even more preferably at least 3 mm to the toe side of the heel-most portion. Thus, the discretionary mass is increased and relocated to the portion of the club head that is more suitable for achieving the desired combination of mass properties, such as the location of the center of gravity of the club head (e.g., center of gravity height, center of gravity depth from the striking face, center of gravity lateral distance from the face center) and moment of inertia, especially Iyy. This greater extension of the auxiliary insert to the central region can itself result in a lateral shift of the center of gravity toward the toe, countering the natural tendency of the center of gravity to be located toward the heel due to the conventional shape of blade-like iron-type, e.g. wedge-type, club heads. Furthermore, the greater extension of the auxiliary insert toward the toe means a larger insert volume and insert mass, as further explained below. The auxiliary insert preferably has a density lower than the density of the body, thereby increasing the discretionary mass, thereby allowing for large increases in moments of inertia, e.g., Izz and Iyy, by selective relocation of such discretionary mass. It has been discovered that the auxiliary insert, as configured in the manner described herein, can be extended in the manner described without adversely affecting performance, including shot dispersion, feel, and acoustic considerations at impact. Moreover, preferably, in an embodiment in which such golf club heads are provided in a correlated set of club heads, the extension of the auxiliary insert from the heel-most portion of the plurality of scorelines to the toe side varies among the club heads in the set as a function of loft. For example, the shape and mass of a lower loft golf club head can tolerate a larger mass (and therefore volume) of the auxiliary insert.

[0020] Then, in a final step 240 of FIG. 7, the result of which is shown in FIG. 12, an insert cap 196 may be introduced into the hosel bore and rest on the metal shelf 159. This insert cap, which may be formed of aluminum or ABS plastic, may provide a protective barrier between the tip of the shaft and the top end of the insert. In other embodiments, if the tip of the shaft is secured in the hosel bore, an insert cap may not be necessary because the top end of the insert is covered by an epoxy layer. By forming the body of the golf club head around the insert in this manner, the space that would otherwise be filled by a denser metal material is instead occupied by, for example, a ceramic material. In this manner, mass is selectively removed from the hosel and heel portion, thereby achieving the goal of moving the center of gravity closer to the face center.

[0021] Other exemplary club heads are considered to be within the spirit and scope of the present invention. For example, as shown in FIG. 13 and as in the method of FIG. 7, an insert 390 may first be formed in a first step 310, for example, by injection molding, and then in a second step 320, the body of the golf club head may be formed around the insert, for example, by lost wax casting. However, instead of removing only the top portion of the insert to form a hosel bore in the hosel portion in a third step 330, more of the insert may be removed to form an internal cavity below the hosel bore. More specifically, as shown in FIG. 14, a portion 392, for example, at least 50% by volume, or all of the insert may be removed, for example, by mechanical agitation, chemical etching, or electrolytic etching, to form the internal cavity. In some aspects, the insert may be comprised of a material that has a high solubility in water or an aqueous solution. In such an aspect, the insert may be easily dissolved from the golf club head to form a cavity. This cavity may then be filled in a fourth step 340 of FIG. 13 by injecting a material therein, such as a polymer foam, which subsequently solidifies. This fourth step can thus introduce vibration dampening material into the club head or tune the location of the center of gravity, for example, by varying the density of a polymeric material. And, similar to the method of Figure 7, in a fifth step 350, an insert cap can then be introduced into the hosel bore so that it rests on a metal ledge that defines the bottom of the hosel bore.

[0022] Still other exemplary club heads are contemplated to be within the spirit and scope of the present invention. For example, as shown in the exemplary golf club head 400 of FIGS. 15-19, the insert 490 may extend further into the sole or toe of the golf club head. The insert may actually extend the entire distance from heel to toe. Such a configuration may be more feasible in a "game improving" type golf club head, which generally has a larger sole volume to accommodate such an insert. Golfers using "game improving" club heads may also find the change in sound and / or feel caused by the insert extending into the striking face less objectionable. In fact, the presence of the insert may provide a vibration dampening effect and improve the feel on off-center impacts. And, as shown in FIG. 19, which is a cross section of the golf club head of FIG. 17 taken along line XIX-XIX, a high density portion 492 may be molded with the insert at the toe or otherwise located within the insert. This high density portion may be a metallic material, such as a tungsten alloy, and may have a mass of 10 g / cm. 3 Including such a high density portion within the insert can be beneficial because it can add mass to the toe of the golf club head to increase the MOI, improve the feel of the golf club head when striking a golf ball, and ultimately reduce manufacturing costs.

[0023] Based on the above structural advances, e.g., increasing discretionary mass while maintaining the center of gravity relatively laterally central, greater attention may be paid to tailoring golf club heads to specific intended users. In considering the desired relocation of mass, a model representative of impact probability is generated for each of a plurality of positions relative to the striking face of the club head. Certain performance characteristics, e.g., ball speed at impact and / or average carry distance, are then measured at each of the plurality of positions relative to the striking face. By relating a probabilistic model to such performance characteristics, a system may be generated that aggregates such information and calculates an overall performance value therefrom representative of what a golfer can expect to achieve over a large sampling of golf shots in play.

[0024] As a result of generating and running such models, various attributes were deemed relatively tolerable or would provide minimal returns if further manipulated, while other attributes were deemed suitable for further manipulation. In other words, where changing some attributes may have adverse effects on other attributes, employing a model with a probability-based overall performance may be able to point to the most desirable combination of attributes.

[0025] In particular, as an example, increasing Iyy was deemed worthy of greater consideration. With wedge-type golf club heads, golfers tend to impact the golf ball with a striking face that has a greater vertical deviation (compared to low lofted iron-type golf clubs). However, the lateral location of the center of gravity remains an important characteristic of wedge-type golf club heads. Other golf club head aspects are also particularly important, such as the height of the sweet spot on the striking face.

[0026] For these reasons, there is a desire to generally maintain, or at least limit manipulation of, various desirable characteristics such as sweet spot height and relatively central lateral placement of the center of gravity in favor of manipulating other characteristics that would significantly increase Iyy.

[0027] This more desirable combination of properties can be achieved in a variety of ways. For example, and as discussed above, the low density insert 190 may comprise a greater mass, a greater volume, and therefore a greater percent volume and percent mass of the overall golf club head.

[0028] First, the inventors have determined that a larger insert mass is feasible without degrading the structural integrity of the golf club head below an acceptable threshold. Second, if multiple different low density inserts are implemented across a set or portfolio or offering of multiple variable loft golf club heads, a larger insert volume can be achieved. If the auxiliary insert was limited to a single identically constructed component across all the different lofted (and otherwise different) club heads of the set or portfolio, the design envelope in which the low density insert could fit would be considered as the net overlap space of all such golf club heads stacked on top of each other in the same orientation. Instead, if multiple different low density inserts are permitted to be incorporated into a set of club heads of different lofts, fewer or no club heads need to be stacked for each low density insert. As a result, the design envelope is generally larger, allowing for greater overall design freedom across the entire set or offering.

[0029] In accordance with the above, the low density insert preferably has a density equivalent to 4 g / cc or less, more preferably 3 g / cc or less, even more preferably 2.5 g / cc or less, and even more preferably about 2 g / cc. Additionally or alternatively, the low density insert has a mass, Ma, of 4 g or more, more preferably 5.5 g or more, more preferably 6 g or more, and even more preferably in the range of 6 g to 8 g. A larger mass here necessarily results in a larger discretionary mass, but the upper limit in this case takes into account practical manufacturing considerations that may tend to put downward pressure on the mass in terms of maintaining the structural integrity of the club head in a range of normal use cases. Furthermore, to the extent that mass is increased by extending the auxiliary insert to the toe side of the scoreline beyond the heel-most portion, there may be less benefit as the removal of mass near the center position of the club head may have less impact on the MOI relative to the removal of mass from the tip position of the club head. Additionally or alternatively, the low density insert includes a volume of 2 cc or more, more preferably 2.75 cc or more, and even more preferably in the range of 2.75 cc to 4 cc. This range reflects similar considerations discussed with respect to the mass of the auxiliary insert.

[0030] Additionally or alternatively, in some embodiments, the auxiliary insert mass Ma constitutes a relatively large percentage of the overall club head mass Mh. The overall club head mass Mh is preferably at least 250g and / or not more than 320g. More preferably, Mh is equal to or greater than 275g and equal to or less than 310g. Most preferably, Mh is within the range of 285g to 305g. Preferably, the ratio Ma / Mh is equal to or greater than 0.0185, and in some such embodiments, equal to or greater than 0.020. Furthermore, in some such embodiments, the ratio Ma / Mh is within the range of 0.0185 to 0.0275. Such parameters refer to the extent to which discretionary mass is generated for relocation to more beneficial areas of the club head and the extent to which mass is removed from less beneficial areas, so that, for example, the center of gravity may be maintained relatively laterally centered relative to the face center, as described herein.

[0031] However, as discussed above, applying multiple low density inserts to a set or offering of club heads of different lofts allows for greater design freedom, at least for a particular loft. The offering, as used herein, refers to a plurality of products having similar aesthetic and functional characteristics, intended and viewed as a single product line, and a user is expected to select from an offering all or a set of fewer than all of the products in the offering to comprise a set or part of a set of golf clubs or golf club heads. Set, or correlated set, as used herein, refers to a plurality of products having similar or correlated functionality and / or aesthetics that are sold or offered for sale in combination. Thus, in addition to or alternatively to the above, the low density insert volume is preferably related to loft throughout the set or offering in the following manner: Volume ≧ 0.0279cc / ° * Loft + 0.7805cc

[0032] As an example, referring to FIG. 30, a portfolio of golf club heads is shown in which various sets of golf club heads may be arranged in accordance with the disclosure above. The portfolio includes a first subset of golf club heads, 500A-500D, each of which preferably share the same effective bounce (bounce option #1) but have a progressive change in loft. The portfolio also includes a second subset of golf club heads, each of which share the same second bounce (bounce option #2) but have a progressive change in loft. The first correlated set of iron-type, and more specifically wedge-type, club heads may comprise club heads having at least two, and more preferably at least three, different lofts selected from among the first subset. The correlated set of club heads may similarly be considered to comprise club heads of two or more different lofts selected from among the second subset. In some alternative embodiments, the correlated set may be comprised of different lofted club heads having different effective bounce attributes. The club head and insert characteristics of bounce options #1 and #2 are shown in Figure 31. Golf club heads 500A-500H may each include one of low density inserts 190A-190F in accordance with the present disclosure, with the low density inserts having the characteristics and shapes shown in Figures 32A-32H.

[0033] As shown in the charts and images of FIGS. 32A-32H, it is therefore contemplated that a set of golf club heads (e.g., set or offering 568) of at least four club heads having unique lofts, e.g., a wedge-type golf club head family, may include low density inserts that vary from one loft club head to another loft club head (in the manner described with respect to FIG. 1) and / or provide other characteristics, e.g., variation in bounce. More specifically, at least six unique supplemental inserts (190A, 190B, 190C, 190D, 190E, and 190F) are embodied in a portfolio 568 of club heads that vary in several combinations of loft and effective bounce. In some embodiments, a unique supplemental insert is provided for each unique club head in the portfolio. However, preferably, several club heads also bear similar or identical supplemental inserts within the portfolio. Thus, greater discretionary mass may be achieved and this discretionary mass may be relocated to more desirable areas of the club head and / or removed from areas of the club head where mass removal may be desirable, such as near the heel and / or near the y-axis (i.e., the horizontal heel-toe axis passing through the center of gravity of the club head when the club head is placed in a nominal position relative to the imaginary ground plane), thus potentially further increasing Iyy.

[0034] Preferably, in combination with enlarging the low density insert as described above, mass is relocated to various ends of the club head, preferably proximate the hosel portion. For example, the incorporation of the low density insert may result in a longer hosel. Preferably, the hosel length is equal to or greater than 78 mm, more preferably equal to or greater than 80 mm, and even more preferably equal to about 85 mm, but preferably not greater than 90 mm. In some such embodiments, the hosel length may be considered a function of loft, with lower loft club heads having lower hosel lengths and higher loft club heads having larger hosel lengths. For example, a club head according to the embodiment of FIG. 1 having a loft of about 42° to about 52° may have a hosel length between about 75 mm and about 82 mm, more preferably about 80 mm, while a club head according to the embodiment of FIG. 1 having a loft of about 56° to about 64° may have a hosel length between about 83 mm and 88 mm, more preferably about 84 mm. In this aspect, the moment of inertia characteristics are further improved. For example, Iyy is believed to increase as mass is relocated to a region more perpendicular to the y-axis. Izz may increase as mass is relocated to a region more laterally to the z-axis along which Izz is measured. Moreover, such an attribute takes advantage of the idea that, from a probabilistic perspective, the variability of impact is greater with loft, thereby increasing the payoff due to increased Iyy with loft. Furthermore, considering that mass is removed near the heel-direction location and relocated near the hosel, the desired lateral (heel-toe) location of the center of gravity may be generally maintained (changes in distance from the axis have a significantly greater effect on MOI than the center of gravity location). Preferably, the center of gravity 670 has a distance D7 (see, for example, FIG. 22) of 5 mm or less from the imaginary vertical center plane 666. However, providing a larger mass and volume of low-density insert may achieve even greater enhancements to this dimension. Thus, D7 is more preferably 2.5 mm or less, and even more preferably 1.25 mm or less.

[0035] Additionally, the center of gravity 670 preferably has a depth D5, (see FIG. 23) from the striking face surface 676 measured normal to the striking face, with positive values ​​corresponding to rearward, of 2.5 mm or less, more preferably 2.25 mm or less, and even more preferably 2 mm or less. In some embodiments, the depth of the center of gravity may be a negative value indicating that the center of gravity is forward of the striking face. Such an embodiment is particularly feasible with a large amount of discretionary mass incorporated into the hosel. These values, on the one hand, qualitatively indicate that the golf club head is blade-like or solid in appearance and / or feel. On the other hand, these values ​​serve as an indication that the sweet spot of the club head is relatively low on the striking face, which may be considered a particularly desirable feature for wedge-type golf club heads given the golf club head's ability to generate beneficial spin at impact.

[0036] Additionally or alternatively, the depth of the center of gravity D5 is preferably related to the loft of the club head, for example, preferably D5≦7.69mm-0.074mm / °*L, more preferably D5≦7.19mm-0.074mm / °*L. These relationships ensure the above-mentioned advantages associated with forming D5 as an absolute value, but take into account the natural tendency of D5 to change relative to the club head loft.

[0037] Based on the above configuration, Iyy is preferably 1000 g cm 2 More preferably, 1100g cm 2 Additionally or alternatively, Izz is preferably 3000 g cm 2 More preferably, 3250g·cm 2 More preferably, 3300 g cm 2 These values ​​are believed to increase the predicted ball carry distance and / or predicted ball impact velocity considered over an array of positions relative to the striking face using the probability-based models described above, thereby increasing the overall predicted performance of the golf club head.

[0038] Referring to FIG. 23, additionally or alternatively, the sweet spot 678 of the club head has a height, D1, measured vertically from the imaginary ground plane 10, preferably 24 mm or less, more preferably between 19 mm and 23 mm. Correspondingly, the center of gravity has a height, D3, preferably 22 mm or less, more preferably within the range of 19 mm to 21.5 mm. Additionally or alternatively, the club head has an overall depth, D4, measured rearward from the striking face surface and perpendicular to the striking face surface, preferably 23 mm or less, more preferably 22 mm or less, even more preferably within the range of 17 mm to 22 mm. The club head further has a toe width dimension D2, which is the lateral distance between the face center and the toe-most portion of the club head. D2 is preferably 44 mm or more, more preferably 45 mm or more, even more preferably within the range of 45 mm to 48 mm. Additionally or alternatively, the club head includes a club head height dimension D6, which is the vertical extent of the body of the club head excluding the hosel portion. The height D6 is preferably equal to or greater than 38 mm, and more preferably within the range of 39 mm to 49 mm.

[0039] As mentioned above, it is contemplated that from a probabilistic modeling perspective, it may be more desirable to enhance Iyy while maintaining or not significantly enhancing Izz. Thus, the ratio of Iyy / Izz is preferably 0.25 or greater, more preferably 0.28 or greater, even more preferably 0.30 or greater, and even more preferably 0.32 or greater. Preferably, such ratio is within the range of 0.30 to 0.35. Such characteristics further improve the overall probabilistic expected performance of the club head.

[0040] In addition to the above, it has been discovered that the loft of the club head plays a particularly important role in establishing and thus governing the appropriate tradeoffs between the various mass-related parameters of a golf club head. For example, it is believed that from a probabilistic perspective, increasing the loft will result in greater user impact variance in the vertical direction about the striking face of the club head. This discovery has led to a focus on the manner in which Iyy varies with loft, and in particular, greater attention being paid to increasing Iyy as the loft increases, possibly at the expense of other attributes that are considered less important.

[0041] Thus, Iyy is preferably related to loft for a club head (or for two, three, or preferably all club heads in a set or portfolio of club heads) in the following manner: Iyy≧16.63g cm 2 / °×L+114g·cm 2

[0042] While it is desirable to increase Iyy with increasing loft, such a goal may come at the expense of increasing the lateral spacing of the center of gravity from the face center (in practical terms, D7). Some increase in D7 is believed to be permissible, but a threshold limiting such inadvertent increases is preferably still applied. As a result, Iyy, D7, and loft are preferably related as follows: Iyy / D7≧527.4g·cm / °×L-23580g·cm More preferably, Iyy, D7 and loft are related as follows: Iyy / D7≧527.4g·cm / °×L-22170g·cm More preferably, Iyy, D7 and loft are related as follows: Iyy / D7≧527.4g·cm / °×L-20760g·cm

[0043] Additionally or alternatively, D7 relates to the loft for a club head (or two, preferably three, and more preferably all of the club heads in a set or portfolio of club heads) in the following manner: D7≦10.1mm-0.135mm / °×L More preferably, D7 relates to the loft for a club head (or two, preferably three, more preferably all of the club heads of a set or portfolio of club heads) in the following manner: D7≦8.75mm-0.135mm / °×L Such a relationship ensures that efforts to increase the moments of inertia, particularly Iyy, do not result in unnecessary overall loss of performance due to inadvertent increases in D7, especially for higher lofted clubheads.

[0044] Additionally or alternatively, Iyy is preferably related to loft in the following manner: Iyy≧16.63g cm 2 / °×L+114g·cm 2

[0045] The uniqueness of these relationships can be illustratively shown from the tables and plots of Figures 33-36, which compare exemplary embodiments of the present disclosure with known prior art golf clubs. As used herein, "CGy" is, by definition, equivalent to D7.

[0046] As mentioned above, one characteristic desired for wedge-type golf club heads is their ability to generate backspin upon impact. In addition to the above-mentioned characteristics such as sweet spot location and moment of inertia, other golf club head aspects can help contribute to backspin generation. Some such attributes are the surface roughness characteristics of the striking face.

[0047] The surface roughness of the striking face of an iron-type, e.g., wedge-type, golf club head is regulated in various ways by organizations that promulgate the rules governing the play of professional golf, such as the United States Golf Association (USGA). In particular, the USGA promulgates rules governing equipment, including rules that limit aspects of surface roughness. These rules are believed, in part, to limit the average surface roughness Ra to 180 μin. However, average surface roughness is only one way of expressing the properties of a surface. As such, complex surface variations are possible within this tolerance range.

[0048] Thus, with particular attention to play in wet conditions, it has been found that the overall performance, such as backspin rate, can be enhanced by appropriate selection of the surfacing process. Preferably, apart from the scorelines formed in the above-mentioned manner, the striking face is textured, preferably by media blasting.

[0049] In one or more embodiments, the striking face is textured, preferably by a surface treatment process including media blasting. Certain processes, and the structures resulting therefrom, have been shown to increase overall backspin generation, and more specifically, significantly increase the amount of backspin in wet conditions. Thus, by using such processes and / or producing such finishes, the gap in spin performance typically understood to exist between dry and wet conditions is minimized, resulting in not only greater overall backspin, but also more consistent club head performance during use.

[0050] In some such embodiments, the process of surfacing the striking face of the club head includes a first step of applying a coating, preferably chrome plating. Preferably, the plating step is followed (but optionally preceded) by a second step of media blasting the striking face. It is believed that the step of applying a chrome plated surface is particularly effective in wet conditions, thereby helping to minimize the gap in spin performance between dry and wet conditions, as discussed above.

[0051] Additionally or alternatively, the surface texture varies from club head to club head within a correlated set of club heads, such as the correlated set of club heads described above.

[0052] More specifically, and by way of example, in some embodiments, the media blasting step preferably includes applying aluminum oxide having a grit of 180 to 120. However, in other cases, particularly considering the particular loft, this step includes applying media comprising a mixture of 180 to 120 grit aluminum oxide and ceramic media. Preferably, such a mixture has a volume ratio of aluminum oxide to ceramic of 8:1 to 10:1, more preferably about a 9:1 volume ratio of aluminum oxide to ceramic.

[0053] With respect to a portfolio or correlated set of golf club heads, such as the portfolios and sets of club heads described herein, preferably, one or more of the high loft club heads undergo media blasting comprising 180-120 grit aluminum oxide, which is preferably not applied to the chrome plated striking face surface. It is further added that, preferably, one or more of the mid-loft club heads (i.e., one or more club heads having less loft than the high loft club heads) of the same portfolio or set undergo similar or similar media blasting, but such media blasting is applied to the chrome plated surface. It is further added that, preferably, one or more of the low loft club heads (i.e., one or more club heads having less loft than the mid loft club heads) of the same portfolio or set undergo media blasting with a mixture of aluminum oxide and ceramic, preferably with a greater volume ratio of aluminum oxide, more preferably with a volume ratio of aluminum oxide to ceramic of 8:1 to 10:1, and even more preferably with a volume ratio of aluminum oxide to ceramic of about 9:1. More preferably, for one or more of the low loft club heads, the media blasting is preferably applied to the chrome plated surface. The incorporation of ceramics into the media blast mix has been shown to be beneficial in that it does not affect the surface as much as pure aluminum oxide, resulting in a surface roughness effect consistent with loft-specific performance expectations. Furthermore, when media blasting is applied to a striking face of a chrome-plated substrate, it is preferred that the chrome layer is not worn away to expose the underlying surface, resulting in concerns of rust / oxidation of such underlying surface. In addition to the specific selection of media blasts and the parameters governing the application of such media blasts, such as blast time and blast angle, it is preferred that the chrome layer is applied to have a sufficient thickness so that it is not worn away in such a way that the underlying surface is exposed. Additionally or alternatively, a third step, preferably following the media blasting step, is performed to further affect the texture of the final, finished striking face.Preferably, the laser etching is applied to the striking face. Moreover, in the case of a set or portfolio, the laser etching is applied in a manner that varies as a function of loft. For example, in some embodiments, the laser etching process results in horizontal "lines" interposed between the scorelines. The "lines" may correspond to textured regions that define areas of the face that are narrow in width and relatively long. Such laser etched regions may correspond to a single horizontal "line" that extends exclusively in a heel-to-toe direction, or may correspond to multiple line segments, each of which is collinear but discrete, thus forming, for example, a dotted appearance. Such laser etched regions may further be characterized as having particularly deep structural features relative to the surrounding striking face portions. More preferably, the laser etching process results in a combination of horizontal "lines" and line segments that extend at an angle (e.g., 5°-80°, more preferably 15°-60°, relative to an imaginary ground, measured in the plane of the striking face). Preferably, the number (and therefore the concentration) of horizontal lines increases with loft. More preferably, the angle of the angled laser etched regions increases with increasing loft (and preferably increases the overall concentration of laser etched regions per unit area of ​​striking face). In part, such laser etched regions provide additional surface roughening that is believed to have the effect of reducing the tolerances in Ra with precision, thus allowing for targeting Ra values ​​closer to the USGA limits. The addition of laser etched regions has also been shown to improve spin performance, especially in wet conditions. Furthermore, such laser etching provides a visual cue to the golfer of the relative degree of surface roughness for club heads of different lofts.

[0054] In some particular embodiments, a "raw" or unplated finish is desired because some golfers prefer such an aesthetic and functional surface finish. In such cases, the striking face may be free of sacrificial or other coatings intended to minimize or prevent rusting or oxidation. In some such cases, additional coatings or chemical applications are introduced to specifically promote rusting or oxidation. In such cases, the risk of eroding the rust-inhibiting surface may not be relevant, and thus, for example, limitations on the grit of the media may be of less concern. Thus, for example, in the case of a set or portfolio of club heads intended for a raw finish, a greater variation in media grit may be applied. For example, in some such embodiments, one or more high loft club heads may be media blasted with 60 grit aluminum oxide, mid loft club heads with 120 grit aluminum oxide, and low loft club heads with 180 grit aluminum oxide. In particular, 60 grit aluminum oxide media is preferably not applied, for example, in the case of chrome plated club heads. However, alternative processes can be applied to allow for the application of such grit, for example by adjusting the way the chrome deposition layer is thickened.

[0055] With respect to construction, the above process results in unique surface characteristics, preferably in a manner that varies with loft in the case of a set or portfolio. Preferably, for any individual club head, the surface texture characteristics are in part a function of loft.

[0056] Overall, as a matter of threshold, the finished striking face preferably meets the equipment rules promulgated by the USGA (and similar regulatory bodies). As noted above, such rules are generally understood to include face textures (excluding scorelines) in iron-type club heads having an average surface roughness Ra not exceeding 180 μin. The USGA equipment rules are also understood to limit the Rz of any striking textures (excluding scorelines) in iron-type club heads to an Rz not exceeding 1000 μin. Thus, preferably, regardless of loft, golf club heads resulting from the above-described surface finishing process have an Ra not exceeding 180 μin, and preferably have an Rz not exceeding 1000 μin. Indeed, in the case of a portfolio or set of club heads, Ra is preferably generally constant among two, more preferably three, and most preferably all of the different lofts of the club heads in the set or portfolio. For example, for two, three or all of the club heads in a set or portfolio of differing lofts, Ra is preferably maintained within the range of 120 μin to 180 μin, and more preferably 140 μin to 180 μin.

[0057] Nevertheless, despite the relative consistency of Ra with loft changes, other standard surface roughness parameters are preferably the focus and preferably vary as a function of loft. For example, the media blast changes discussed above are believed to correlate with a high (and increasing with loft) developed interface developed area ratio Sdr. This parameter may be considered to be related to the relative surface area of ​​the surface in practical terms. Increasing the surface area is believed to be measurable in terms of Sdr and has been shown to result in significant improvements in spin performance, especially in wet spin conditions. The striking face surface of the golf club head described above with respect to FIG. 1 preferably has an Sdr of 1% or more, more preferably 2% or more, and even more preferably 3% or more. Such values ​​provide a unique interaction between the metal face, the elastomeric golf ball coating, and moisture, resulting in a dynamic interaction that produces high performance in terms of backspin generation. Moreover, such favorable performance results are believed to achieve certain synergistic results of such surface roughness attributes in combination with the mass attributes (e.g., center of gravity location, and moment of inertia characteristics) discussed above with respect to the embodiment of FIG. 1.

[0058] Additionally or alternatively, Sdr varies as a function of loft, and thus preferably varies within a correlated set or portfolio of golf club heads. For example, the absolute difference between Sdr values ​​of club heads of different lofts in a common set is preferably 0.75% or more, more preferably 1.0% or more. Such variation and values ​​are further illustrated in the plots shown in Figures 37A and 37B. Preferably, such variation occurs between a first club head having a loft in the range of 46°-52° and a second club head having a loft in the range of 56°-64°.

[0059] As with average surface roughness Ra, and perhaps many common surface roughness parameters, it is rare that a single attribute is purely indicative of the resulting phenomenon without further additional qualification. For example, the R 2As shown in the plot of modeling in FIG. 38, Sdr is believed to be highly correlated with performance.

[0060] However, it is further believed that a surface with a relatively uniform distribution of high surface area is the primary factor corresponding to a significant improvement in spin performance. The above complex dynamic interactions are believed to act, in part, on the moisture cohesive properties, surface tension properties and adsorption properties of the substrate material. In other words, a surface that inadvertently but in a non-uniform manner bears high Sdr may not produce the beneficial results achieved herein. As an example, from a practical point of view, a useful means for quantifying this distinction is yet another common metric parameter, the "protruding valley depth ratio to core", or Spk / Sk.

[0061] Additionally or alternatively, the striking face of the club head of the above embodiments preferably has an Spk / Sk of 2 or less, and more preferably 1 or less, as shown in the plots of Figures 39A and 39B.

[0062] Additionally or alternatively, with respect to an embodiment of a portfolio of club heads, such a portfolio preferably includes wedge-type club heads with different characteristics apart from loft. For example, the portfolio of club heads preferably includes varying bounce offerings, such as low bounce, mid bounce and full bounce options. In such a case, the leading edge radius varies for each of the low bounce, mid bounce and full bounce cases in conjunction with the varying sole grind characteristics. Specifically, the leading edge radius preferably increases from low bounce to mid bounce and from mid bounce to full bounce. In Figs. 20-24, another club head embodiment is shown. The golf club head 600 of Figs. 20-24 preferably includes all of the features and characteristics described above with respect to the embodiment of Fig. 1, but differs in its outer contour and appearance. For example, this club head 600 preferably includes a prominent mass feature 612, such as a triangular mass feature located in the upper toe region 610 of the club head behind the striking face 660. More preferably, the first rigid element 614 and the second rigid element 616 are disposed on the rear surface 682 of the striking face. Such elements may further facilitate ensuring the structural integrity of the club head while increasing discretionary mass for achieving the potential properties discussed above with respect to the embodiment of FIG.

[0063] 25-29, another club head embodiment is shown. The golf club head 700 of FIGS. 25-29 preferably includes all the features and characteristics described above with respect to the embodiment of FIG. 1, but has a different exterior profile and appearance. For example, the club head 700 preferably includes a prominent mass feature 712, such as a triangular mass feature located in the upper toe region 710 of the club head behind the striking face 760. Further, and preferably, specifically with reference to FIG. 29, a medallion 714 is secured to the rear surface 782 of the striking face, and an insert 716, preferably in the form of a cover, is associated with the upper surface of the lower (e.g., muscle) portion of the rear portion 780 of the club head. The golf club head 700 generally takes the form of a blade-like wedge-type golf club head. However, the club may specifically be configured as a "game improvement" style wedge-type club head, for example, having hybrid features that make the club head suitable for golfers of higher handicap levels. For example, the muscle portion may include a recess having mass features therein and / or a rearwardly disposed mass insert, preferably having a density greater than that of the body. For example, such insert may have a density of 8 g / cc or greater, more preferably 10 g / cc or greater. For continuity, the recesses, one preferably located proximate the heel portion 720 of the club head and the other preferably located proximate the toe portion 710 of the club head, are covered by the cover described above. The cover may be mechanically secured to the muscle portion on the underside of the rear portion 780 of the club head by an interlocking fit, such as, for example, a fastener and / or a press fit. Alternatively or additionally, a chemical adhesive may be applied to bond the cover to such rear portion of the club head. Furthermore, in some embodiments, and with particular reference to FIG. 28, the striking face 760 of the club head may include a plurality of scorelines 762 extending substantially across the striking face. Such allows the golfer to have greater flexibility in shot selection as well as greater forgiveness in the case of higher handicap golfers.Such features also benefit from the potential mass properties applied to the golf club head as described above with respect to the embodiment of Figure 1. Such elements further facilitate ensuring the structural integrity of the club head while increasing any mass to achieve the potential properties described above with respect to the embodiment of Figure 1.

[0064] Figures 40-44 illustrate yet another embodiment of a golf club head. Unless otherwise noted, the golf club head illustrated and described in Figures 40-44 substantially includes the features and characteristics described above with respect to the embodiment of Figure 1. Moreover, the golf club head illustrated and described, particularly with respect to Figures 40 and 42, is part of a series of interrelated club heads and is preferably representative of one or more other golf clubs (or club heads) in the series of interrelated golf club heads. It should be understood that the series of golf club heads may include additional golf club heads that include features similar to those illustrated and described in Figures 40-44.

[0065] The set of golf club heads may include a set of iron-type golf club heads. As such, the lofts of the golf club heads may vary between 18 degrees and 56 degrees, or between 20 degrees and 54 degrees. In some examples, the set of golf club heads may include "game improvement" style iron-type club heads. Although the set of golf club heads described herein may include cavity back style golf club heads, it should be understood that the set of golf club heads may also or alternatively include hollow back style golf club heads.

[0066] FIG. 40 illustrates a front view of a first golf club head 800 of a set of golf club heads. The golf club head 800 may include a high loft iron, where the loft angle is between 30 degrees and 54 degrees. However, the features of the golf club head 800 illustrated and described with respect to FIG. 40 may be incorporated into iron-type golf club heads having a loft less than 30 degrees or greater than 54 degrees. The golf club head 800 may include a body 802. The body 802 may include a top portion 804, a sole portion 806 opposite the top portion, a toe portion 808, and a heel portion 810 opposite the toe portion 808. The body 802 may further include a hosel portion 812 extending from the heel portion 810. The hosel portion 812 may include a hosel bore 814 with an open end 816 for receiving a shaft of a golf club and a support surface 818 configured to support the shaft of the golf club.

[0067] In some examples, the golf club head 800 can include an auxiliary component 822 located at least partially within the auxiliary recess 820. As previously described, the auxiliary component 822 can be formed of a different material than the body 802 of the golf club head 800 and can therefore include different material properties than the body 802. In some examples, the auxiliary component 822 can be at least partially encased by the body 802. The auxiliary component 822 can be substantially similar to the insert 190 previously described. The auxiliary component 822 can include a substantially similar volume as the auxiliary recess 820. Additionally, the auxiliary component can include a mass of 4.0 g or more, 4.5 g or more, or 5.0 g or more.

[0068] As shown in FIG. 40, the incorporation of ancillary components 822 within an iron-type club head, particularly where the density of ancillary components 822 is less than the density of the club head body or at least adjacent portions of the hosel region, can increase and relocate any mass to a more suitable portion of the club head to achieve a desired combination of mass properties, such as the location of the club head's center of gravity (e.g., the height of the center of gravity, the depth of the center of gravity from the striking surface, and the lateral spacing of the center of gravity from the center of the face) and moments of inertia, particularly Iyy or Izz.

[0069] 40, the auxiliary recess 820 and corresponding auxiliary component 822 may extend from the heel portion 810 toward the toe portion 808. In some examples, the auxiliary recess 820 and auxiliary component 822 extend only to a heel-side maximum extension 823 of a scoreline 824 formed in a striking face 826 of the golf club head 800. Alternatively, in some examples, the auxiliary recess 820 and auxiliary component 822 may terminate at a location heelward of the heel-side maximum extension 823 of the scoreline 824 (as shown in FIG. 40).

[0070] 41 illustrates a rear view of golf club head 800 having auxiliary recess 820 and auxiliary component 822 disposed within auxiliary recess 820. As previously described, golf club head 800 includes a perimeter weighting element 828 disposed on the rear side of the striking wall that defines a rearwardly open main cavity, thereby contributing to optionally identifying the club head as a cavity back style iron-type golf club head.

[0071] FIG. 42 illustrates a front view of a second golf club head 900 of the set of golf club heads. The golf club head 900 may include, for example, a lofted iron having a second loft less than the loft of the club head of FIG. 41, which may include a loft less than 30 degrees. However, the features of the golf club head 900 shown and described with respect to FIG. 42 may be incorporated into an iron-type golf club head having a loft angle greater than 30 degrees in some examples. The golf club head 900 may include a body 902. The body 902 may include a top portion 904, a sole portion 906 opposite the top portion 904, a toe portion 908, and a heel portion 910 opposite the toe portion 908. The body 902 may further include a hosel portion 912 extending from the heel portion 910. The hosel portion 912 may include a hosel bore 914 having an open end 916 for receiving a golf club shaft and a support surface 918 configured to support the golf club shaft. The hosel portion 912 may also include a second bore 920 extending from the support surface 918 in a sole direction. In some examples, the second bore 920 and the hosel bore 914 extend along a hosel axis 922 of the hosel portion 912. In some examples, the second bore 920 may have a volume of less than about (e.g., + / - 0.1 cc) 1.0 cc, less than about 0.75 cc, or less than about 0.7 cc.

[0072] In some examples, the second bore 920 may be empty, or the second bore 920 may be partially or wholly occupied by an insert or ancillary component. In examples where the second bore 920 is occupied, the second bore 920 may be occupied by an ancillary component similar to the ancillary components shown and described with respect to Figures 40 and 41, except that the insert disposed within the second bore 920 will be sized to fit within the volume of the second bore 920.

[0073] 43 illustrates a rear view of the golf club head 900. As previously mentioned, the golf club head 900 includes a perimeter weighting element 924 located behind the striking wall, which contributes to the identity of the club head 900 as a cavity back style iron-type golf club head.

[0074] In some examples, one or more of the lower lofted club heads (e.g., less than 30 degrees) in a club set omit the auxiliary recess, e.g., have a solidly constructed hosel portion in favor of an alternative feature, while one or more of the higher lofted club heads (e.g., club heads having lofts greater than 30 degrees) preferably include such an auxiliary recess. For example, club head 900 may include a striking face 926 having a variable face thickness. In some such embodiments, such a variable face thickness pattern is absent in one or more of the higher lofted club heads or, alternatively, is distinct from a second variable face thickness pattern in one or more of the higher lofted club heads.

[0075] FIG. 44 illustrates a partial rear view of an exemplary rear surface 928 of a striking face 926 of a club head 900. As shown in FIG. 44, the rear surface 928 includes recesses in an upper region, a center region, a toe region, and a lower region. More specifically, the rear surface 928 includes an upper region groove or channel 930, a toe region groove or channel 932, and a lower region groove or channel 934 adjacent the periphery of the rear surface 928. A center region recess 936 (or a main recess) is formed in a center region between the upper region groove 930, the toe region groove 932, and the lower region groove 934. An intermediate region 938 surrounds the center region recess 936 and each of the upper region groove 930, the toe region groove 932, and the lower region groove 934. Additionally, the average thickness of the intermediate region 938 is greater than each of the center region recess 936, the upper region groove 930, the toe region groove 932, and the lower region groove 934.

[0076] Such variable face thickness may be used in lower loft irons in place of auxiliary recesses and auxiliary components, as lower loft irons benefit less from the provision of auxiliary recesses. Instead, the variable face thickness may improve the mass and performance characteristics of the club head 900 while maintaining similar stress limits, appearance, and overall club head weight. In some examples, the improved mass and performance characteristics may include, for example, the coefficient of restitution (COR), characteristic time (CT), moment of inertia (MOI), and / or center of gravity (CG) location of the club head 900. In some examples, a cavity back or hollow body iron-type club head has an improved variable face thickness pattern that allows for the movement of discretionary weight from the striking face of the club head to other areas of the club head to improve the mass and / or performance characteristics of the club head 900. Advantageously, such a club head may have improved mass and performance characteristics, such as a higher COR, a higher MOI, and a more laterally centered, deeper, and lower CG location on the striking face than a comparable club head while maintaining similar stress limits. Additionally, such club heads do not sacrifice traditional looks, dimensions (e.g., blade length, topline thickness), and overall club head weight (e.g., swing weight) that may be preferred by some players.

[0077] In some examples, in addition to or instead of the variable face thickness features described above, one or more of the lower lofted irons (e.g., less than 30 degrees) may include a surface treatment applied to the striking face 926 of the golf club head 900 that is different from the surface treatment applied to one or more striking faces 826 of the higher lofted (e.g., between 30 degrees and 54 degrees) clubs of the club set.

[0078] For example, the first golf club head 800 may have a coating applied to at least the striking face 826 of the first golf club head 800. Such a coating may include chrome plating. Once the coating is applied to the striking face 826, a first media blast may be applied to the striking face 826. The first media blast may incorporate media such as aluminum oxide and / or may have a grit between 180-120.

[0079] Alternatively or in addition, the second golf club head 900 may also have a similar, but preferably different, coating applied to at least the striking face 926 of the second golf club head 900 from the face coating described with respect to the club head 800. Such a coating may include chrome plating. Once the coating is applied to the striking face 926, a second media blast is applied to the striking face 926. The second media blast in this case preferably incorporates a different media than that incorporated with respect to the face coating of the club head 800 described above. Such a difference may be, for example, in the composition of the media and / or the grain size of the media. For example, preferably, the second media includes a mixture of aluminum oxide and ceramic media, the aluminum oxide having a grit between 180 and 120. The second media blast may include a volume ratio of aluminum oxide to ceramic media of 8:1 to 10:1, respectively. Different methods of surfacing the higher and lower lofted club sets may result in more desirable spin characteristics across various shot types and under various conditions, which may provide greater consistency across the entire golf club set. Such surfacing processes and results have been described in more detail previously.

[0080] In the foregoing discussion, the present invention has been described with reference to certain exemplary embodiments thereof. However, it will be apparent that various modifications and changes can be made to these exemplary embodiments without departing from the broader spirit and scope of the present invention. Accordingly, the foregoing discussion and the accompanying drawings are to be regarded as merely illustrative of the present invention, rather than limiting its scope in any manner. [Explanation of symbols]

[0081] 100 Golf Club Heads 110 Toe 120 Heel 130 Top Section 140 Sole 150 Hosel part 154 hosel bore 160 hitting face 164 Face Center 166 Vertical center plane 170 Center of gravity 818 Support surface

Claims

1. A golf club head, when placed in a reference position relative to a virtual ground plane, Loft angle between 20° and 54°; A head body, The top part and a sole portion opposite the top portion; A heel portion, a toe portion opposite the heel portion; a hosel portion extending from said heel portion, said hosel portion including a hosel bore having an open end for receiving a golf club shaft and a support surface configured to support said golf club shaft, and an auxiliary recess extending from said support surface toward a sole, said auxiliary recess having a volume between 2 cubic centimeters and 3.5 cubic centimeters; a head body including a striking face having a face center and defining an imaginary face plane; an imaginary vertical center plane perpendicular to the imaginary face plane and passing through the face center; and A center of gravity within 5 mm of said imaginary vertical central plane, A golf club head including:

2. the head body is formed of a first material having a first melting point and a first density; the golf club head further includes a support element formed of a second material having a second melting point greater than the first melting point and a second density less than the first density; The golf club head of claim 1 , wherein the auxiliary element is at least partially disposed within the auxiliary recess and at least partially enveloped by the first material.

3. The golf club head of claim 2 , wherein the auxiliary element comprises a ceramic material.

4. The second density is 2.5 g / cm ３ 3. The golf club head of claim 2, wherein:

5. The golf club head of claim 2 , wherein the auxiliary element includes an element mass Ma of 4.5 g or greater.

6. The golf club head of claim 2 , wherein the auxiliary element has an element mass Ma of 5.0 g or greater.

7. The golf club head of claim 2 , wherein the auxiliary element comprises a volume of 2.5 cc or greater.

8. The striking face further comprises: a central region including a face center, the central region having a first average thickness; an upper region above the central region, the upper region having a second average thickness; a tow region located on a toe side of the central region, the tow region having a third average thickness; and 2. The golf club head of claim 1, further comprising an intermediate region at least partially surrounding the central region and disposed between the central region and each of the top region and the toe region, the intermediate region having a fourth average thickness greater than the first average thickness, the second average thickness and the third average thickness.

9. The golf club head of claim 1 , comprising a cavity back style head.

10. 1. A golf club headset comprising: a first golf club head and a second golf club head; the first golf club head includes a first loft between 30° and 54° and a first body; The first body includes: A first top portion; a first sole portion opposite the first top portion; A first heel portion; a first toe portion opposite the first heel portion; a first hosel portion extending from the first heel portion, the first hosel bore including a first open end for receiving a golf club shaft and a first support surface configured to support the golf club shaft, and a first auxiliary recess extending from the first support surface toward a sole, the first auxiliary recess having a volume greater than 2.25 cubic centimeters; the second golf club head includes a second loft less than 30° and a second body; The second body includes: A second top portion; a second sole portion opposite the second top portion; A second heel portion; a second toe portion opposite the second heel portion; a second hosel portion extending from the second heel portion, the second hosel bore including a second open end for receiving a golf club shaft and a second support surface configured to support the golf club shaft; and a second auxiliary recess extending from the second support surface toward a sole, the second auxiliary recess having a volume of less than one cubic centimeter. Golf club headset.

11. The second body further includes a striking face having a face center, the striking face comprising: a central region including a face center, the central region having a first average thickness; an upper region above the central region, the upper region having a second average thickness; a toe region located to the toe side of the central region, the toe region having a third average thickness; and 11. The golf club headset of claim 10, including an intermediate region at least partially surrounding the central region and disposed between the central region and each of the upper region and the toe region, the intermediate region having a fourth average thickness greater than the first average thickness, the second average thickness and the third average thickness.

12. The golf club headset of claim 10 , wherein the second hosel bore and the second auxiliary recess extend along a hosel axis of the second hosel portion.

13. the first body is formed of a first material having a first melting point and a first density; the first golf club head further includes a support element formed of a second material having a second melting point higher than the first melting point and a second density lower than the first density; The golf club headset of claim 10 , wherein the auxiliary element is at least partially disposed within the first auxiliary recess and at least partially encased by the first material.

14. The golf club headset of claim 10 , wherein the first golf club head and the second golf club head comprise cavity back style heads.

15. 1. A method of forming an interrelated set of golf club heads, comprising: Providing a first golf club head including a first striking face and a first hosel portion, providing a first golf club head, the first hosel portion including a first hosel bore including a first open end for receiving a golf club shaft and a first support surface configured to support the golf club shaft, and an auxiliary recess extending from the first support surface in a sole direction, the auxiliary recess having a volume greater than 2.25 cubic centimeters; applying a coating to at least the first striking face of the first golf club head; applying a first media blast to the first striking face, the first media blast including aluminum oxide having a grit between 180 and 120; providing a second golf club head including a second striking face and a second hosel portion; providing a second golf club head, the second hosel portion including a second hosel bore including a second open end for receiving a golf club shaft and a second support surface configured to support the golf club shaft, and the second bore extending from the second support surface in a sole direction, the second bore having a volume of less than one cubic centimeter; applying the coating to at least the second striking face of the second golf club head; and applying a second media blast to the second striking face, the second media blast comprising a mixture of aluminum oxide and ceramic media, the aluminum oxide having a grit between 180 and 120; 23. A method of forming an interrelated set of golf club heads comprising:

16. The method of claim 15 , wherein the coating comprises a chrome plating.

17. 16. The method of claim 15, wherein the second media blast has a volume ratio of aluminum oxide to ceramic media of 8:1 to 10:1, respectively.

18. The method of claim 15 , wherein the correlated set of golf club heads includes a plurality of cavity back style golf club heads.

19. The first golf club head includes a first body formed of a first material having a first melting point and a first density; the first golf club head further includes a support element formed of a second material having a second melting point higher than the first melting point and a second density lower than the first density; The method of claim 15 , wherein the auxiliary element is at least partially located within the auxiliary recess and at least partially surrounded by the first material.

20. The method of claim 15 , further comprising laser etching at least a portion of the first striking face of the first golf club head.

Images