Patent Application
20230364478
Golf club heads have mass and performance properties that affect the quality and consistency of shots when hitting a golf ball. Such mass and performance properties are often related to the mass or the distribution of mass in the golf club head. Examples of such mass and performance properties can include the location of a Center of Gravity (CG) for the club head, Coefficients of Restitution (CORs) or Characteristic Times (CTs) at various locations on a striking face of the club head, and Moments of Inertia (MOIs) about different virtual axes passing through the CG.
As example of a mass property affecting performance, the location of the CG can affect, for example, how high a golf ball is hit, the amount of spin on the golf ball, or the forgiveness of a club head in terms of ball speed and straightness for shots where the impact occurs at off-center locations away from a “sweet spot” on the striking face. As conventionally defined, the sweet spot is the point on the striking face from which a normal projection passes through the club head's CG. For example, moving the CG lower toward the sole, and back from the striking face of an iron type club head can advantageously increase the height of shots for longer distance and result in more backspin on the golf ball for a more controlled shot. Locating the sweet spot closer to the center of the striking face may also better align the sweet spot to a player's expected sweet spot location. Due to the asymmetric shaping and mass distribution of traditional iron-type golf club heads, a laterally centered CG location typically requires, for example, including high density weights, which can be costly and negatively affect swing weight.
As another example of a mass property affecting performance, greater MOIs in a club head mean that the club head is more resistant to twisting when the golf ball is hit at off-center positions on the striking face that are farther from the sweet spot. Increasing the MOIs of the club head generally results in the club head being more stable or forgiving for off-center shots, allowing such off-center shots to be straighter and have a faster ball speed due to the greater MOIs.
As an example of a performance property, the COR is a measurement of energy loss or energy transfer between the striking face and the golf ball. Higher measured CORs on the striking face translate to less energy loss or better energy transfer when the striking face impacts the golf ball. More energy is transferred to the golf ball with a higher COR, which translates to a faster ball speed that typically results in a farther shot. The COR can be measured, for example, using conventional cannon testing in keeping with the United States Golf Association's (USGA's) prescribed method for determining the COR. In this regard, the USGA has migrated from using the COR to using a different performance property referred to as a Characteristic Time (CT) measurement to quantify the elasticity of the striking face. For all purposes herein, the CT refers to characteristic time as described in the USGA's “Procedure for Measuring the Flexibility of a Golf Clubhead” (Rev. 1.0.0, May 1, 2008).
The improvement of mass and performance properties of a club head are balanced against structural requirements for the intended use of the club head, such as stress properties. Mass and performance properties are also balanced against other limits, such as limits prescribed by regulatory bodies, such as the USGA, concerning the CT, dimensions, and club head mass. In addition, players generally have implicit expectations for club heads, such as an overall appearance with respect to size, or an overall expected weight of the club head for the type of golf club or the loft angle of the golf club.
The present inventors recognized a need for a variable face thickness pattern for golf club heads, particularly iron-type club heads, that improves mass and performance properties of club heads, while maintaining similar stress limits, appearance, and overall club head weight. As discussed in more detail below, the improved mass and performance properties can include, for example, Coefficients of Restitution (CORs), Characteristic Times (CTs), Moments of Inertia (MOIs), and/or a Center of Gravity (CG) location for the club head. In some example embodiments, a cavity-back or a hollow bodied, iron-type club head has an improved variable face thickness pattern that allows for discretionary weight to be moved from the striking face of the club head to other areas of the club head to improve mass and/or performance properties of the club head. Advantageously, such club heads may have improved mass and performance properties, such as higher CORs on the striking face, higher MOIs, and more laterally centered, deeper, and lower CG locations than comparable club heads, while maintaining similar stress limits. Additionally, such club heads do not sacrifice traditional appearances, dimensions (e.g., blade length, topline thickness), and overall club head weight (e.g., swing weight) that may be preferred by some players.
Reducing weight in the face while maintaining an overall club head weight can be important for players who may associate specific lofts of a golf club head with a certain mass, and have a preferred golf club swing weight. Generally, when presented in a set, iron-type club heads increase in mass with loft. For example, the mass of iron-type club heads may adhere to the following equation:
mh=2.1 g/degree*LA+a, Equation 1
where mh is a club head mass in grams, LA is the loft angle of the club head when orientated in a reference position, and a is between 190 g and 210 g. In one or more embodiments, a golf club head maintains such a head mass mh, while having an improved face thickness pattern. Such a club head may have an improved face thickness pattern with a vertical MOI extending through the CG, Izz, that satisfies:
Izz>mh*9.0 cm2. Equation 2
In one or more aspects of the disclosure, a golf club head, when orientated in the reference position, includes a golf club head main body having a toe, a heel opposite the toe, a sole, and a top portion opposite the sole. The club head has a mass mh that satisfies Equation 1. In addition, the club head has a blade length less than 80 mm. The striking face of the club head defines a face plane and has a face center, and a virtual center plane extends vertically through the face center perpendicular to the face plane. As used herein, a face center of a striking face is determined according to the procedure described in the USGA's “Procedure for Measuring the Flexibility of a Golf Clubhead” (Rev. 2.0, Mar. 25, 2005). A CG of the club head is located not more than 2.0 mm from the virtual center plane, and an MOI about a vertical axis extending through the CG, Izz, satisfies Izz>mh*9.3 cm2.
In some aspects, the striking face includes a central region including the face center, an intermediate region at least partially surrounding the central region, an upper region above the central region, an upper region above the central region, a lower region below the central region, and a toe region toe-ward of the central region. Each of the central region, the upper region, the lower region, and the toe region include a maximum width and an average thickness, and the intermediate region is disposed between the central region and each of the upper region, the lower region, and the toe region. The intermediate region has an average thickness greater than that of each of the central region, the upper region, the lower region, and the toe region. In one or more embodiments, the intermediate region fully surrounds the central region.
According to some aspects, at least one of the toe region, the upper region, and the lower region includes, on a rear surface thereof, an elongate groove or recess having a width no less than about 2.0 mm. Alternatively or additionally, the upper region, the lower region, and the toe region respectively include, on a rear surface thereof, an upper groove or recess extending generally in a heel to toe direction, a lower groove or recess extending generally in a heel to toe direction, and a toe groove or recess extending generally in a top to bottom direction.
In one or more aspects of the disclosure, a golf club head, when orientated in a reference position, includes a golf club head main body having a toe, a heel opposite the toe, a sole, and a top portion opposite the sole. A face insert of the club head has a mass mf fixedly attached to the golf club head main body and includes a striking face that defines a face plane. The club head has a mass mh that satisfies Equation 1. The club head has a blade length less than 80 mm, and an MOI, Izz, about a vertical axis extending through a CG of the club head that satisfies Izz>mh*9.3 cm2. In addition, a ratio mf/mh is less than or equal to 0.22. In one or more embodiments, the ratio mf/mh of an iron-type golf club head is less than or equal to 0.20.
In some aspects, the striking face includes a sweet spot corresponding to a first COR, COR1, and an auxiliary location spaced at least 7.5 mm from the sweet spot corresponding to a second COR, COR2, where: COR2≥0.98*COR1. In some implementations, a variable thickness of the striking face may provide for a higher COR near the sweet spot, increase the COR in a region including the sweet spot, and/or provide a larger area of a higher COR near the sweet spot. In another aspect, the relocation of mass from the striking face can move the CG so that the sweet spot corresponds to an area with a higher COR and/or a more frequently hit area of the striking face by players. For example, the central region of the striking face may include a heel-side region that has a greater thickness than a toe-side region so as to improve the COR in areas of the striking face that are more commonly hit by players.
The recesses or grooves on the rear surface of striking faces of the present disclosure not only increase the COR of the striking face, but can also improve weight distribution of the club head by relocating mass from the striking face to other areas of the club head to increase MOIs and/or to better locate the CG of the club head for better performance. The recesses or grooves may also be determined with a stress limit on the striking face as a constraint so that the striking face is comparable to prior art club heads when tested for durability, despite the reduced mass of the striking face.
In one or more aspects of the disclosure, a method of manufacturing a golf club head includes forming a golf club head main body having a striking face, a heel portion, a toe portion opposite the heel portion, a sole, a top portion opposite the sole, and a blade length no greater than 80 mm. A thickness pattern of the striking face is formed by defining on the striking face a central region including the face center, an intermediate region at least partially surrounding the central region, and at least one of an upper region above the central region, a lower region below the central region, and a toe region toe-ward of the central region. The intermediate region can be disposed between the central region and each of, or at least one of, the upper region, the lower region, and the toe region. The central region is recessed such that the central region has a thickness less than the intermediate region. At least one of the toe region, the upper region, and the lower region is recessed such that the recessed region has a thickness less than that of the central region. The variable face thickness pattern is formed such that the striking face includes a sweet spot corresponding to a first COR, COR1, and an auxiliary location spaced at least 7.5 mm from the sweet spot corresponding to a second COR, COR2, where COR2≥0.98*COR1.
In one or more aspects of the disclosure, a method of manufacturing a golf club head includes forming a golf club head main body having a striking face, a heel, a toe opposite the heel, a sole, and a top portion opposite the sole. A variable thickness pattern is determined with a computing device by defining on the striking face a plurality of parameterization zones, including a central zone having the face center. Each of the parameterization zones includes at least one of a variable first parameter and a variable second parameter. A target value is set for at least one of a respective first constraint, second constraint, and third constraint. Each of the at least one variable first parameter and second parameter is varied for each of the parameterization zones. Impact of the striking face with a golf ball is simulated, and resultant values are evaluated against the target value for the at least one of first constraint, second constraint, and third constraint. The determined variable thickness pattern is formed on the striking face based on the evaluation. In some implementations, the first constraint is a striking face mass, the second constraint is mechanical stress on the striking face, and the third constraint is a weighted COR representing an overall effective or expected COR for the striking face based on the CORs for different portions of the striking face that have been weighted by their expected golf ball impact probabilities. In addition, the variable first parameter and the variable second parameter, in some implementations, may include a variable maximum width and a variable thickness for the parameterization zone or region.
In one or more aspects of the disclosure, a method of manufacturing a golf club head includes forming a golf club head main body having a striking face, a heel, a toe opposite the heel, a sole, and a top portion opposite the sole. A variable thickness pattern is determined with a computing device by defining on the striking face a central region including a face center of the striking face, an intermediate region at least partially surrounding the central region, an upper region above the central region, a lower region below the central region, and a toe region toe-ward of the central region. Each of the central region, the upper region, the lower region, and the toe region includes a variable width parameter and a variable thickness parameter. The intermediate region is disposed between the central region and each of the upper region, the lower region, and the toe region. A target value is set for at least one of a respective first constraint, second constraint, and third constraint. Each of the variable first parameter and the variable second parameter is varied for each region of the striking face. Impact of the striking face with a golf ball is simulated, and resultant values are evaluated against the target value for the at least one first constraint, second constraint, and third constraint. The determined variable thickness pattern is formed on the striking face based on the evaluation.
In one or more aspects of the disclosure, a set of iron-type golf clubs includes golf club heads that, when oriented in a reference position, each include a striking face comprising a face center and a variable thickness, a shell including a crown, a sole opposite the crown, a heel, a toe, and an internal weight pad located on a lower portion of the shell. The golf club heads in the set have a loft angle LA of at least 20 degrees and a center of gravity having a center of gravity depth D. The center of gravity depths of at least two of the golf club heads satisfy the equation:
D=a—b*LA, Equation 3
with 19 mm<a<22 mm and b=0.36 mm/degrees, and with the at least two golf club heads having a difference in loft L of at least 5 degrees. A moment of inertia about a vertical axis through the center of gravity of each of the at least two golf club heads is at least 2900 g*cm2.
In one or more aspects of the disclosure, an iron-type golf club head, when orientated in a reference position, includes a striking face comprising a face center and a variable thickness with a center region having a first thickness T1, an intermediate region having a second thickness T2 surrounding the center region, and a perimeter region surrounding the intermediate region having a third thickness T3, and with T2<T1<T3. The golf club head further comprises a shell including a crown, a sole opposite the crown, a heel, a toe, and an internal weight pad located on a lower portion of the shell. A loft angle LA of the golf club head is at least 20 degrees, and the golf club head has a center of gravity depth D satisfying Equation 3 above, with 19 mm<a<22 mm and b=0.36 mm/degrees. A moment of inertia about a vertical axis through the center of gravity is at least 2900 g*cm2.
The various exemplary aspects described above may be implemented individually or in various combinations. The foregoing features and advantages, as well as other features and advantages, of the golf club heads of the present disclosure will become apparent to those of ordinary skill in the art after consideration of the following description, the accompanying drawings, and the appended claims.
The features and advantages of the embodiments of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the drawings. The drawings and the associated descriptions are provided to illustrate embodiments of the disclosure, and not to limit the scope of what is claimed.
Representative examples of one or more novel and nonobvious aspects and features of the golf club heads and methods of manufacturing such club heads as disclosed below are not intended to be limiting in any manner. Furthermore, the various aspects and features of the present disclosure may be used alone or in a variety of novel and nonobvious combinations and sub-combinations with one another.
In
In one or more embodiments, LA ranges from about 18 degrees to about 40 degrees. In other embodiments, the golf club head is a wedge-type golf club head and LA ranges from about 40 degrees to about 64 degrees.
As shown in
In the example of
As discussed in more detail below, striking face 109 has been formed with a variable thickness in different regions or parameterization zones of striking face 109 to provide improved mass and/or performance properties of club head 100. Such properties can include, for example, greater Coefficients of Restitution (CORs) and/or greater Characteristic Times (CTs) on a larger area and/or more commonly hit area of striking face 109, greater Moments of Inertia (MOIs) about a virtual vertical CG axis (e.g., virtual vertical CG axis 24 in
A total mass of the club head may serve as a target total mass comprised of structural mass and discretionary mass. Structural mass as used herein generally refers to mass necessary to establish a minimum structural integrity for the club head to be operable for its intended use. Discretionary mass, on the other hand, can refer to the remaining mass that, given a target mass, is not needed to establish the minimum structural integrity of the club head, and may therefore be located primarily to adjust mass and/or performance properties of the club head.
For example, the thickness of different regions or parameterization zones of striking face 109 can result in mass being moved from such regions or parameterization zones to other locations in club head 100 to provide higher MOIs of club head 100 and an improved location for the CG of club head 100 (e.g., CG 18 in
As noted above, the variable thickness pattern of the striking face discussed in more detail below can increase the COR at locations on striking face 109 corresponding to more commonly hit locations or a larger area of striking face to provide better energy transfer for off-center shots or for a statistically greater number of shots. Additionally or alternatively, the disclosed variable thickness patterns for a striking face can increase the area of the striking face that has a relatively high COR. For example, in some implementations, striking face 109 in
As shown in
Club head 100 in
As noted above, the mass for iron-type club heads typically vary based on the Loft Angle (LA). When presented in a set, iron-type club heads can increase in mass with loft. For example, the mass of iron-type club heads may adhere the following equation:
mh=2.1 g/degree*LA+a, Equation 1
where mh is a club head mass, LA is the loft angle of the club head when orientated in a reference position, and a is between 190 g and 210 g. In some implementations, club head 100 maintains such a head mass, mh, while having an improved face thickness pattern.
As shown in
The rear surface of striking face 109 also includes intermediate region 108 at least partially surrounding the central region including central region recess 120. In this regard, intermediate region 108 includes upper intermediate region 108U and lower intermediate region 108L above and below central region recess 120, respectively. Each of the central region, the upper region, and the lower region including central region recess 120, upper region groove 118, and lower region groove 122, respectively, has an average thickness that is less than the average thickness of intermediate region 108, which may have an approximately uniform thickness. Upper region groove 118 and lower region groove 122 may extend in generally a heel to toe direction, as in the examples of upper region grooves 318 and 418 and lower region grooves 322 and 422 in
In some implementations, at least one of upper region groove 118 and lower region groove 122 can be an elongate groove having a width no less than approximately 2.0 mm. In addition, thickness of central region recess 120 may taper in some embodiments such that a heel-side region of the central recess may be thicker than a toe-side region of the central recess, as in the example of central region recess 320 in
In
Izz>mh*9.3 cm2 Equation 2
where mh is the mass of club head 100. As noted above, increasing the MOI about virtual vertical axis 24 extending through CG 18 improves the forgiveness of club head 100 so as to cause less bending of club head 100 about virtual vertical axis 24 during off-center shots in a horizontal direction along striking face 109 (e.g., shots that are more toe-ward or heel-ward of sweet spot 16).
In addition, the variable thickness pattern of striking face 109 can increase the COR at locations on striking face 109 corresponding to more commonly hit locations or a larger area of striking face to provide better energy transfer for off-center shots or for a statistically greater number of shots. The variable thickness pattern of striking face 109 with upper region groove 118, central region recess 120, and lower region groove 122 can increase the area of the striking face that has a relatively high COR.
For example, mass removed from particular areas of striking face 109 can improve the COR of striking face 109, and the removed mass can be relocated in club head 100 so that CG 18 can be advantageously located closer to a lateral center of striking face 109, closer to virtual ground plane 13, and farther behind striking face 109. In such an example, mass removed or saved from striking face 109 to form upper region groove 118, lower region groove 122, and central region recess 120, such as by machining (e.g., grinding, milling) or by a known casting or forging process, can be relocated to rear muscle 116 to lower the location of CG 18 and move CG 18 farther behind striking face 109. As another example, mass removed from striking face 109 can be relocated from a heel-side of striking face 109 to a toe-side of striking face 109 to move CG 18 away from heel portion 104 toward toe portion 102.
Those of ordinary skill in the art will appreciate with reference to the present disclosure that other implementations may vary from the arrangement shown in
As shown in
Club head 200 in
As noted above, the mass for iron-type club heads typically vary based on the Loft Angle (LA). As shown in
The rear surface of striking face 209 also includes intermediate region 208 at least partially surrounding the central region including central region recess 220. In this regard, intermediate region 208 includes upper intermediate region 208U and lower intermediate region 208L above and below central region recess 220, respectively. Each of the central region including central region recess 220, and the upper region including upper region groove or recess 218 has an average thickness that is less than the average thickness of intermediate region 208. In some implementations, intermediate region 208 may have an approximately uniform thickness. Upper region groove 218 may extend in generally a heel to toe direction, as in the examples of upper region grooves 318 and 418 in
In some implementations, upper region groove 218 can have an elongate groove having a width no less than approximately 2.0 mm. In addition, a thickness of central region recess 220 may taper in some implementations such that a heel-side region of the central recess may be thicker than a toe-side region of the central recess, as in the example of central region recess 320 in
Such a tapering or variation of the central region thickness or central recess can also ordinarily improve the COR in the central region and/or increase an area of striking face 209 having a greater COR, as discussed below in more detail with reference to
For example, mass removed from particular areas of striking face 209 can improve the COR of striking face 209, and the removed mass can be relocated in club head 200 so that CG 48 can be advantageously located closer to a lateral center of striking face 209, closer to virtual ground plane 13, and farther behind striking face 209. In such an example, mass removed from striking face 209 to form upper region groove 218 and central region recess 220, such as by machining or by a known casting or forging process, can be relocated to rear muscle 216 to lower the location of CG 48 and move CG 48 farther behind striking face 209. In some implementations, striking face 209 can be formed separately and attached to a main body of club head 200 by welding or other known methods. As another example, mass removed from striking face 209 can be relocated from a heel-side of striking face 209 to a toe-side of striking face 209 to move CG 48 away from heel portion 204 toward toe portion 202.
As a result, the sweet spot on striking face 209 (e.g., sweet spot 16 in
As noted above, the variable thickness pattern of the striking face can increase the COR at locations on striking face 209 corresponding to more commonly hit locations to provide better energy transfer for a statistically greater number of shots, resulting in an improved weighted COR for the striking face. Additionally or alternatively, the disclosed variable thickness patterns for a striking face can increase the area of the striking face that has a relatively high COR. For example, in some implementations, striking face 209 may include a maximum COR no less than 0.80 at a first location, and a COR of no less than 98% of the maximum COR at an auxiliary location on striking face 209 that is no less than 7.5 mm from the first location. In such implementations, the first location corresponding to the maximum COR may be at or near the sweet spot, such as within 5 mm of the sweet spot. Some implementations of variable thickness patterns discussed below for improving CORs on the striking face include, for example, a central region of the striking face having a heel-side thickness greater than a toe-side region.
In
Those of ordinary skill in the art will appreciate with reference to the present disclosure that other implementations may vary from the arrangements shown in
Preferred dimensions of central region recess 320 have a face thickness of no more than 2.5 mm, that preferably tapers from 2.3 mm on a heel-side of central region recess 320 to 1.9 mm on a toe-side of central region recess 320. Preferred dimensions of upper region groove 318 have a face thickness of no more than 1.5 mm, and a maximum width of no less than 5.0 mm. Preferred dimensions of toe region groove 326 have a face thickness less than upper region groove 318, and a maximum width no less than 2.0 mm. Preferred dimensions of lower region groove 322 have a face thickness of no more than 1.5 mm, that is preferably greater than toe region recess 326, and a width no less than 2.5 mm. As referred to herein, the width of a groove or channel is defined by a maximum perpendicular distance between the longer opposite sides of the groove or channel. A preferred thickness of intermediate region 308 surrounding the recesses of central region recess 320, upper region groove 318, toe region groove 326, and lower region groove 322 has a thickness less than 3 mm and greater than 2.5 mm, and preferably about 2.7 mm.
Some preferred dimensions for the recesses of rear surface 328 in
The foregoing preferred dimensions for central region recess 320, upper region groove 318, toe region groove 326, and lower region groove 322 improve performance and mass related properties of cavity-back club heads. Such performance and mass related properties include, for example, the CG location for the club head, CORs or CTs at various locations on the striking face, and MOIs about different virtual axes passing through the CG. The recesses on rear surface 328 not only increase the COR of striking face 309 with a reduction of mass in striking face 309 at particular locations, but can also improve the weight distribution of the club head to increase MOIs and/or better locate the CG for performance, as discussed above. The recesses on rear surface 328 may also be determined with maximum face stress as a constraint so that striking face 309 is comparable to prior art club heads when tested for durability, despite the reduced mass of striking face 309.
Those of ordinary skill in the art will appreciate with reference to the present disclosure that other implementations of a rear surface of a striking face for a cavity-back club head may differ from the arrangement shown in the example of
In addition, rear surface 428 includes upper region groove or channel 418, toe region groove or channel 426, and lower region groove or channel 422 that are adjacent a periphery of rear surface 428. Central region recess 420 is formed in a central region between upper region groove 418, toe region groove 426, and lower region groove 422. Intermediate region 408 surrounds central region recess 420 and is disposed between central region recess 420 and each of upper region groove 418, toe region groove 426, and lower region groove 422. In addition, intermediate region 408 has an average thickness that is greater than that of each of central region recess 420, upper region groove 418, toe region groove 426, and lower region groove 422.
Some preferred thicknesses in striking face 409 for the recesses of rear surface 428 in
The foregoing preferred dimensions for central region recess 420 (i.e., middle central region recess 437, heel-side central region recess 435, and toe-side central region recess 433), upper region groove 418, toe region groove 426, and lower region groove 422 improve performance and mass related properties of hollow club heads. Such performance and mass related properties include, for example, the CG location for the club head, CORs or CTs at various locations on the striking face, and MOIs about different virtual axes passing through the CG. In this regard, Table 4 below provides measured or computer-simulated values for the removal of mass from striking face 409, the COR at face center 54, the COR at an off-center location 58 that is 7.5 mm toe-ward of sweet spot 56, and a weighted COR representing an expected or overall COR for striking face 409 that is calculated by weighting the CORs at different locations on striking face 409 using a probability that a golf ball will be hit at the location.
In some implementations, striking face 409 can include a maximum COR no less than 0.80 at a first location, such as at or within 5 mm of sweet spot 46, and a COR no less than 98% of the maximum COR at a second location 48 that is no less than 7.5 mm from the first location. The thicknesses of the recesses of striking face 409 may also be determined so as to increase a weighted COR. The weighted COR can be determined based on a bin-by-bin or location-by-location impact probability, as discussed in more detail in U.S. Pat. No. 10,456,643, titled “GOLF CLUB HEAD,” and filed on Dec. 28, 2018, the entire contents of which are hereby incorporated by reference. The weighted COR, “expected COR” or “overall COR” may be considered to represent a probability-adjusted measure of club head performance that a typical golfer would actually expect given how impacts are empirically dispersed about striking face 409. Using such information, a golfer may make a more informed decision in selecting a golf club based on its weighted COR. Alternatively or additionally, a golfer may determine which golf clubs may be better suited to the golfer's specific handicap or skill level.
The weighted COR can be determined by superimposing onto striking face 409 a rectangular virtual evaluation region comprising a first pair of horizontal sides having a length of 35 mm, a second pair of vertical sides having a length of 25 mm, and a geometric center that coincides with the face center. The rectangular virtual evaluation region is divided into bins by dividing the rectangular virtual evaluation region into five rows (i.e., m=5) having equal height of 5 mm, and seven columns (i.e., n=7) having equal width of 5 mm, thereby forming a matrix of bins having coordinates i and j. An average COR is determined (e.g., measured or computer-simulated) for each bin represented by its coordinates i, j, and the weighted COR can be determined by Equation 3 below. In other implementations, a COR may be determined for a center position of each bin.
Weighted COR=Σi=1nΣj=1mpij*cij Equation 4
where pij is an impact probability for the bin at coordinates i,j according to an impact probability matrix, such as Table 3 below.
Other impact probability matrices may be used to determine the weighted COR in different implementations. For example, other impact probability matrices for determining a weighted COR or expected COR can include those disclosed in U.S. Pat. No. 10,456,643 incorporated by reference above. As another example variation, the measurement locations for the CORs can correspond to points or a differently shaped boundary than the rectangular bins described above for Table 3. In yet other variations, the COR measurement locations can correspond to areas that are spaced apart form each other that do not abut. As another example variation, the orientation of the bins or COR measurement locations may not form a rectangular matrix, but rather, an irregular arrangement of a different configuration, such as an annulus or sunburst configuration.
The recesses on rear surface 428 not only increase CORs of striking face 409 with a reduction of mass in striking face 409 at particular locations, but can also improve the weight distribution of the club head to increase MOIs and/or better locate the CG for performance, as discussed above. The recesses on rear surface 428 may also be determined with maximum face stress as a constraint so that striking face 409 is comparable to prior art club heads when tested for durability, despite the reduced mass of striking face 409.
With reference to the dimensions in Table 2 above for the recesses of rear surface 428 in
Those of ordinary skill will appreciate with reference to the present disclosure that other arrangements of recesses are possible than those shown in
In this regard, Table 5 below provides preferred striking face thicknesses and widths for recesses in variations of striking face 409 that do not include lower region groove 422, but still include heel-side central region recess 435, middle central region recess 437, toe-side central region 433, upper region groove 418, and toe-side region groove 426. All of the recesses in Table 5 below can have a radius of 0.4 mm between a bottom of the recess having the indicated thickness and an adjoining wall.
As shown in
In this regard, preferred thicknesses are provided in Table 6 below for the parameterization zones or regions shown in
As shown above, the thicknesses across the striking face of Comparable Club Head D are nearly uniform with a small variation in thickness among the different regions. In contrast, middle central region 537 of Club Head 1D is much thicker than the other regions, and especially thicker than toe central region 535, upper region 536, and lower region 534. As shown in Table 7 below, such variations in the thickness of striking face 509 provide an increased weighted COR and an increased maximum COR, as compared to those of Comparable Club Head D. In addition, the variable thickness pattern of Club Head 1D also reduces the mass of striking face 509 by 6 g, while maintaining a similar or improved stress limit, and thereby providing a similar or greater durability than Comparable Club Head D. The removed or saved 6 g of mass from striking face 509 may be redistributed to other portions of the club head, such as to a rear muscle or toe portion to increase MOIs, and/or to better locate the CG and sweet spot for the club head, as discussed above.
Those of ordinary skill in the art with reference to the present disclosure will appreciate that other implementations can include differently shaped or arranged regions or parameterization zones than those shown in the example of
As shown in
In this regard, preferred thicknesses are provided in Table 8 below for the parameterization zones or regions shown in
As shown above, central region 620 is generally much thicker than outer region 630, with toe-side inner central region 642 and heel-side central region 640 being even thicker than outer central region 644. As shown in Table 7 below, such variations in the thickness of striking face 609 provide an increased weighted COR and an increased maximum COR, as compared to those of Comparable Club Head D discussed above with reference to Table 7. In addition, the variable thickness patterns of Club Heads 1E and 2E also reduce the mass of striking face 609 as compared to Comparable Club Head D by 6 g and 7 g, respectively, while maintaining a similar stress limit, and thereby providing a similar durability as Comparable Head D. The removed or saved 6 g or 7 g of mass from striking face 609 may be redistributed to other portions of the club head, such as to a rear muscle or toe portion to increase MOIs, and/or to better position the CG and sweet spot for the club head, as discussed above.
In block 1102, a plurality of parameterization zones or regions are defined for a striking face of a club head. The club head can be formed with a club head body having a striking face, a heel portion, a toe portion opposite the heel portion, a sole, and a top portion opposite the sole. The club head may be formed, for example, of a steel material, and may include a hollow body type club head or a cavity-back type club head. Each parameterization zone or region may have a variable first parameter and a variable second parameter. In some implementations, the first and second parameters can include a thickness and a width, or other dimension of the parameterization zone or region.
In block 1104, a target value is set for each constraint value for the striking face. In some implementations, a first constraint value can be a striking face mass, a second constraint value can be a mechanical stress limit of the striking face, and a third constraint can be a weighted COR value for the striking face, as described above. The target value for each parameterization zone or region may be set, for example, based on desired improvements for the club head, such as an increased amount of discretionary mass to be redistributed from the striking face, an increased or minimum durability for the striking face, or an increased weighted COR that is balanced against rules for a maximum COR or CT set by a regulatory body.
In block 1106, the parameters of each parameterization zone or region are varied. For example, a maximum width and a thickness may be varied as parameters for each of a central region, upper region, lower region, and toe region of the striking face. In some implementations, the parameters may be iteratively varied to generate sets of values for the one or more constraint values based on the changes to the parameters.
In block 1108, impact with a golf ball is optionally simulated for a plurality of impact locations. In some implementations blocks 1106 and 1108 may be combined. For example, an impact probability matrix as in Table 3 above may be used with Equation 4 above to generate a weighted COR based on variations of first and second parameters for the parameterization zones or regions in block 1106.
In block 1110, constraint values resulting from the variation of parameters in block 1106 are evaluated with respect to the target value for one or more constraint values. For example, a resultant weighted COR value closest to 0.80 may at least in part determine the width and thicknesses of the parameterization zones or regions. As another example, a greatest mass removal or mass savings from the striking face may be another factor considered in determining a size and/or thickness of a parameterization zone or region.
In block 1112, a variable thickness pattern is formed on the striking face based on the evaluation in block 1110. In some cases, a rear surface of the striking face can have material removed using a cutting tool or other machining to form the variable thickness pattern. In other cases, the variable thickness pattern on the striking face may be formed by using a casting or forging process.
Those of ordinary skill in the art will appreciate with reference to the present disclosure that the thickness pattern forming process of
In block 1202, regions of a striking face of a club head are defined including a central region, an intermediate region, and at least one of an upper region, lower region, and toe region. The club head can be formed with a club head body having a striking face, a heel portion, a toe portion opposite the heel portion, a sole, and a top portion opposite the sole. The club head may be formed, for example, of a steel material, and may include a hollow body type club head or a cavity-back type club head. The central region includes a face center of the striking face, and the intermediate region at least partially surrounds the central region. The upper region can be located above the central region, and a lower region can be located below the central region. A toe region can be located toe-ward of the central region. The intermediate region can be disposed between the central region and each of, or at least one of, the upper region, lower region, and toe region.
In block 1204, the central region is recessed such that the central region has a thickness less than the intermediate region. In this regard, the intermediate region may have a uniform or approximately uniform thickness, such as a thickness of at least 2.5 mm and no more than 3.3 mm. The recess of the central region may be made by, for example, tapering the central region from a toe side of the central region to a heel side of the central region. In other implementations, the thickness of the central region may vary with stepwise changes in thickness to form the recess. The recess of the central region may be formed, for example, by machining to remove mass or by forging or casting at least a portion of the club head to save mass from the central region.
In block 1206, at least one of the toe region, upper region, and lower region is recessed, such as with a groove or channel, such that the recessed region has a thickness less than that of the central region. Such a groove may include, for example, an elongate groove having a width no less than about 2.0 mm in at least one of the toe region, upper region, and lower region. The groove may be formed, for example, by machining to remove mass or by forging or casting at least a portion of the club head to save mass from the at least one region. In some implementations, the upper region may include an elongate groove or channel having a width of no less than 6.0 mm.
The recess of the central region formed in block 1204 and the recess of at least one of the toe region, upper region, and lower region in block 1206 result in a striking face that includes a sweet spot corresponding to a first COR, COR1, and an auxiliary location spaced at least 7.5 mm from the sweet spot and corresponding to a second COR, CORAUX, where COR2≥0.98*COR1. In this regard, the foregoing addition of recesses and corresponding removal of mass or mass savings from the striking face increases an area of the striking face that has a relatively high COR. In some implementations, a maximum COR for the striking face may also be increased or better positioned to correspond to a sweet spot and/or a more frequently hit portion of the striking face, as may be quantified with a weighted COR, as discussed above.
In addition, the removal or saving of mass from the striking face can also allow for redistribution of the mass in the club head, such as to a rear muscle or toe portion of the club head, so as to increase MOIs and/or better position the club head CG and striking face sweet spot. For example, a sweet spot may be located not more than 2.0 mm from a vertical center plane perpendicular to the face plane and extending through the face center. As another example, a CG for the club head may be located not more than 1.0 mm from the vertical center plane so as to better position the sweet spot on the face with an expected location or more frequently hit location.
As shown in
The thicknesses and shapes of the center region, the intermediate region, and the perimeter region can be determined using, for example, a thickness pattern forming process as discussed above for
In one example resulting from such a thickness pattern forming process, a simulated weighted COR was increased from 0.696 for a striking face with a uniform face thickness of 2.3 mm to a simulated weighted COR of 0.720 with the varying thicknesses of T1, T2, and T3 of the center, intermediate, and perimeter regions provided above for striking face 709. In addition, the maximum simulated COR for the striking face of uniform thickness 2.3 mm was increased in this example with the varying thicknesses of T1, T2, and T3 of the center, intermediate, and perimeter regions provided above for striking face 709. In implementations where golf club head 700 forms part of a set of iron-type golf clubs, some or all of the golf club heads in the set can have a weighted COR of at least 0.70 determined using the probability matrix of Table 3 above and Equation 4.
As shown in
The CG depth D of golf club head 700 is measured perpendicularly from face plane 72 to CG 68, which is at an intersection of virtual vertical CG axis 74 and virtual horizontal CG axis 75. As shown in
D=a—b*LA, Equation 3
with 19 mm<a<22 mm and b=0.36 mm/degrees, and more preferably, with 20 mm<a<21 mm and b=0.36 mm/degrees. In implementations where golf club head 700 forms part of a set of iron-type golf club heads, each club head in the set can satisfy Equation 3 above, with 19 mm<a<22 mm and b=0.36 mm/degrees, and with at least two golf club heads in the set having a value for a within 20 mm<a<21 mm. The shape and mass distribution of the internal weight pad can be used to precisely tune properties, such as CG depth, for each club in the set. In this regard, a deeper CG depth (i.e., a greater value for D in Equation 3 above) can provide an improved accuracy on mishits or off-center shots, resulting in a more forgiving club head; a higher CG depth may therefore be more desirable in a lower lofted golf club head.
In addition, the redistribution of mass from striking face 709 and/or the redistribution of mass for an internal weight pad can provide an MOI about virtual vertical CG axis 74 (i.e., Izz in
In this regard,
As shown in
As discussed above, weight pad 816 may be reshaped into weight pad 817 using a computing device or other electronic processing device to determine a mass distribution for the weight pad using target values for constraints such as Izz, Ixx, maximum stress, and/or CG location (e.g., CG depth, CG height, and/or relation of sweet spot to striking face center). In some implementations, a topology optimization software, such as Altair's OptiStruct, may be used with a design space of the mesh internal volume of club head 702 as partially shown on the right side of
As shown in
Shell 705 includes a crown, a sole opposite the crown, a heel, a toe, and an internal weight pad 824 located on a lower portion of the shell 705. Internal weight pad 824 may be integrally formed with the shell 705 or may comprise a separate component. Weight pad 824 can be defined as the portion of the sole portion or lower portion of shell 705 that has a thickness greater than a generally constant baseline or minimum lower shell or sole thickness. The weight pad thickness is then the total lower wall thickness minus the baseline or minimum lower shell or sole thickness. As shown in
In addition, golf club head 706 includes a weight port that receives removable weight 719 on a toe portion of the golf club head. The removable weight 719 can be used to provide further mass property customization or improvement, such as to adjust MOIs, CG locations, and/or swing weight of the golf club.
Shell 803 includes a crown, a sole opposite the crown, a heel, a toe, and internal weight pad 826 located on a lower portion of the shell 803. Internal weight pad 826 may be integrally formed with the shell 803 or may comprise a separate component. Weight pad 826 can be defined as the portion of the sole portion or lower portion of shell 803 that has a thickness greater than a generally constant baseline or minimum lower shell or sole thickness. The weight pad thickness is then the total lower wall thickness minus the baseline or minimum lower shell or sole thickness. As shown in
In addition, golf club head 800 includes a weight port that receives removable weight 819 on a toe portion of the golf club head. The removable weight 819 can be used to provide further mass property customization or improvement, such as to adjust MOIs, CG locations, and/or swing weight of the golf club.
Shell 903 includes a crown, a sole opposite the crown, a heel, a toe, and internal weight pad 828 located on a lower portion of the shell 903. Internal weight pad 828 may be integrally formed with the shell 903 or may comprise a separate component. Weight pad 828 can be defined as the portion of the sole portion or lower portion of shell 903 that has a thickness greater than a generally constant baseline or minimum lower shell or sole thickness. The weight pad thickness is then the total lower wall thickness minus the baseline or minimum lower shell or sole thickness. As shown in
In addition, golf club head 900 includes a weight port that receives removable weight 919 on a toe portion of the golf club head. The removable weight 919 can be used to provide further mass property customization or improvement, such as to adjust MOIs, CG locations, and/or swing weight of the golf club.
As shown in
The lengths of the sole rails across the sole widths generally become shorter as the loft of the golf club heads increase with increasingly shorter sole rails 8a and 8b for golf club head 10008 across sole 10118, and sole rails 9a and 9b for golf club head 10009 across sole 10119. In this regard, outer sole rails 8b and 9b stop at or before reaching halfway across the sole from the trailing edge to the leading edge. For short-iron golf club heads 1000P, 1000D, and 1000S for a pitching wedge club, a dual wedge club, and a sand wedge club, only relatively short center sole rails Pa, Da, and Sa remain proximate the trailing edge (e.g., within 3 mm forward of the trailing edge). In addition, and as discussed in more detail below with reference to
The foregoing arrangement of sole rails can provide for different ground interface effects related to the different angles of attack during a downswing of clubs in the set having different club lengths. For example, the varying sole rails depicted in the set shown in
The foregoing description of the disclosed example embodiments is provided to enable any person of ordinary skill in the art to make or use the embodiments in the present disclosure. Various modifications to these examples will be readily apparent to those of ordinary skill in the art, and the principles disclosed herein may be applied to other examples without departing from the scope of the present disclosure. For example, some alternative embodiments may include different sizes or shapes of regions or parameterization zones of a striking face or different sizes or shapes of internal weight pads. Accordingly, the described embodiments are to be considered in all respects only as illustrative and not restrictive, and the scope of the disclosure is, therefore, indicated by the following claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. In addition, the use of language in the form of “at least one of A and B” in the following claims should be understood to mean “only A, only B, or both A and B.”
This application is a continuation of U.S. application Ser. No. 17/328,611, titled “GOLF CLUB HEAD” (Atty. Docket No. CLG-00800-CIP), and filed on May 24, 2021, which is a continuation-in-part of U.S. application Ser. No. 16/920,504, titled “GOLF CLUB HEADS WITH VARIABLE FACE THICKNESS” (Atty. Docket No. CLG-00800), and filed on Jul. 3, 2020. The entire contents of both of the foregoing applications are hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17328611 | May 2021 | US |
| Child | 18227455 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16920504 | Jul 2020 | US |
| Child | 17328611 | US |
