BACKGROUND
The game of golf in simple terms involves minimizing the number of strokes with a golf club necessary to land a golf ball in a cup at a distance from a starting point, or tee box, over a number of holes throughout a course. To cope with inevitable variations in intended shot distances and variations in turf or other externalities, golfers tend to carry an array of golf clubs that differ in some respects. For example, golfers may carry a driver designed with the intention of hitting a golf ball off a tee and for relatively long distances. On the other hand, wedges are designed with the intention of, e.g., by virtue of loft and contouring, hitting shots of relatively shorter distances and off turf or from sand bunkers.
While a highly-varied assortment of clubs may be beneficial for these reasons, several considerations weigh against an increasingly-varied assortment of clubs to be carried by a golfer during play. Most notably, various regulatory bodies that govern the professional and tournament play of golf have promulgated rules limiting the number of golf clubs that a golfer may carry. For example, the United States Golf Association (USGA) permits golfers to carry no more than 14 clubs in their bag. Apart from such rules, increasing the number of carried clubs bears greater monetary cost to which some golfers may be sensitive. Further, increasing the number of carried clubs, in some cases, increases the carrying weight a golfer must bear, which may result in physical burden.
Provided the above desires and drawbacks, golf club manufacturers have configured clubs to each serve a particular function such that a complete set of clubs provides a golfer with high overall effectiveness. However, traditional delegations of clubs may not be most effective for some classes of golfers.
SUMMARY
The present inventors recognized that some types of golfers generally do not benefit from variations among clubs in a typical complete set; such types of golfers may benefit more from alternative modes of variation. For example, a typical complete set of golf clubs may include a sub-set of iron-type clubs that progress in loft in increments of about 5° or less than 5°. Such loft increment may be intended to predictably result in respective shot distance increments of about 10 to 15 yards for the same golf swing.
However, some classes of golfers, such as those with relatively high handicaps or otherwise inconsistent swing performance, may not hit the ball consistently enough to regularly play to these distance gaps. Put another way, such classes of golfers may exhibit shot dispersion sufficiently large as to render an intended 10 to 15 yard gap increment unnecessarily precise. At the same time, the same class of golfers may benefit more greatly from set variation of an attribute other than low granularity loft variation. For example, a complete set of clubs may include a subset of iron-type clubs including two or more clubs with a greater difference in successive loft angles, such as providing say a corresponding twenty to twenty-five yard gap. By increasing loft increment across the same overall range of lofts, one or more iron-type clubs may be removed. This frees up carrying budget for one more clubs providing modes of variation other than loft, such as one or more clubs designed for interaction with different turf conditions, such as for tee, rough, or loose soil turf conditions, without significantly increasing the cost of, or number of clubs in the set. Such correlated sets with clubs designed for different turf conditions can ordinarily provide overall better performance for such players than having a set of conventional clubs with more tightly grouped loft angles designed for interaction with a single turf condition, such as with a conventional set of iron-type clubs designed for use on a fairway turf condition.
In some aspects of the disclosure, a correlated set of golf clubs includes a first club having a first loft L1 that is between 15° and 45°, and a second club successively lofted relative to the first club and having a second loft L2 that is between 15° and 45° and is greater than L1 by at least 6°. The correlated set of golf clubs further includes a third club successively lofted relative to the second club and has a third loft L3 between 15° and 45° that is greater than L2 by at least 6°. A fourth club of the correlated set includes one of: (a) a loft L4 substantially equal to L1 and differing from the first club with respect to a first physical feature; (b) a loft L4 substantially equal to L2 and differing from the second club with respect to a second physical feature; and (c) a loft L4 substantially equal to L3 and differing from the third club with respect to a third physical feature.
In some aspects, the first physical feature, the second physical feature and the third physical feature are selected from the group consisting of: a club length, a moment of inertia for the club's head, a sole contour of the club head, a leading edge height of the club head, a club head volume, a center of gravity height for the club head, a leading edge radius of the club head, a striking face surface area, a striking face surface texture, and a club head mass.
In other aspects of the disclosure, a correlated set of golf clubs includes a first club having a first loft L1 between 15° and 45° with a first club head having a first striking face and a first center of gravity spaced rearward from the first striking face by a distance D1. The correlated set of golf clubs further includes a second club successively lofted relative to the first club and having a second loft L2 between 15° and 45° that is greater than L1 by at least 5°. A second club head of the second club has a second striking face and a second center of gravity spaced rearward from the second striking face by a distance D2. A third club of the correlated set is successively lofted relative to the second club and has a third loft L3 between 15° and 45° that is greater than L2 by at least 5°. The third club has a third club head having a third striking face with a third center of gravity spaced rearward from the second striking face by a distance D3. The correlated set of golf clubs further includes a fourth club comprising a fourth club head that, when oriented in a reference position relative a virtual ground plane, includes a fourth striking face and a fourth center of gravity spaced rearward from the fourth striking face by a distance D4. The fourth club head has a moment of inertia, Izz, measured about a virtual vertical axis passing through the fourth center of gravity, with Izz being no less than 3400 g·cm2. The fourth club further includes one of: (a) a loft substantially equal to L1, with D4 being greater than D1; (b) a loft substantially equal to L2, with D4 being greater than D2; and (c) a loft substantially equal to L3, with D4 being greater than D3.
According to one or more other aspects, a method of forming a correlated set of golf clubs includes forming a first club head to have a first loft L1 between 15° and 45° and shaping the first club head to be suitable for interaction with a first turf condition. A second club head is formed successively lofted relative to the first club head and having a second loft L2 between 15° and 45° that is greater than L1 by at least 5°. The second club head is shaped to be suitable for interaction with the first turf condition. A third club head is formed successively lofted relative to the second club head and having a third loft L3 between 15° and 45° that is greater than L2 by at least 5°. The third club head is shaped to be suitable for interaction with the first turf condition. A fourth club head is formed, including shaping the fourth club head to be suitable for interaction with a second turf condition that is different from the first turf condition. The fourth club head further includes one of: (a) a loft L4 substantially equal to L1; (b) a loft L4 substantially equal to L2; and (c) a loft L4 substantially equal to L3.
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 sets and methods of making the same disclosed herein will become apparent to those of ordinary skill in the art after consideration of the following description, the accompanying drawings, and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
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.
FIG. 1 illustrates an exemplary set of correlated golf clubs according to one or more embodiments.
FIG. 2A provides front views of two club heads from the correlated set of golf clubs in FIG. 1 according to one or more embodiments.
FIG. 2B provides cross-section views of the club heads of FIG. 2A according to one or more embodiments.
FIG. 2C provides cross-section views of two additional club heads from the correlated set of golf clubs in FIG. 1 according to one or more embodiments.
FIG. 3 is a flowchart for a process of forming a correlated set of golf clubs according to one or more embodiments.
FIG. 4A is a loft plot of an exemplary set of correlated golf clubs according to one or more embodiments.
FIG. 4B is a loft plot of an exemplary set of correlated golf clubs according to one or more embodiments.
FIG. 4C is a loft plot of an exemplary set of correlated golf clubs according to one or more embodiments.
FIG. 4D is a loft plot of an exemplary set of correlated golf clubs according to one or more embodiments.
DETAILED DESCRIPTION
Representative examples of one or more novel and nonobvious aspects and features of the correlated golf club sets and methods of manufacturing the same 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.
A correlated set of golf clubs is a set of clubs that are configured with the intent to be sold together. A correlated set of golf clubs includes a plurality of clubs that exhibit some similar attributes, such as shaping, aesthetics, branding indicia and general class or purpose, yet differ from each other in at least one material aspect, the interchange of which according to a predetermined or conventional scheme. A complete set of golf clubs, as used herein, refers to a plurality of golf clubs intended to correspond to the full array of golf clubs necessary for the play of golf. In some cases, a complete set may include one or more correlated sets of clubs therewithin, i.e., the correlated set being a subset of the complete set. For example, a complete set of golf clubs may include a correlated set of iron-type clubs, yet include other clubs such as woods, wedges, and a putter.
A correlated set of golf clubs may be designed with different loft angles to hit a golf ball with different launch trajectories and amounts of spin that affect the distance the ball travels. The clubs in a such a correlated set are typically designed to have a similar swing weight and feel, which can help the player develop a consistent swing. Generally, higher lofted clubs (i.e., clubs with higher loft angles) provide a higher flight trajectory and greater spin.
As used herein, a “successively lofted” golf club, relative to a correlated set of golf clubs, refers to the club having an immediately next greater loft than a previous club.
FIG. 1 illustrates an exemplary correlated set of golf clubs 100 according to one or more embodiments. As shown in FIG. 1, correlated set of golf clubs 100 is a set of iron-type golf clubs including differently-lofted golf clubs each with indicia located on the sole identifying a club designation (e.g., “4” for a 4-iron club) and a corresponding loft angle (e.g., 21° for the 4-iron club). In the example of FIG. 1, correlated set of golf clubs 100 includes a 4-iron club with a loft of 21°, a first 5-iron club with a loft of 23.5°, a second 5-iron club with a loft substantially equal to, and preferably equal to, the first 5-iron club of 23.5°, a first 7-iron club with a loft of 31°, a second 7-iron club with a loft substantially equal to, and preferably equal to, the first 7-iron club of 31°, a 9-iron club with a loft of 39°, and a pitching wedge club 70 with a loft of 44°. As used herein, “a loft substantially equal to” can mean loft angles that are within 1.5° of each other. In this embodiment, a loft difference between the 5F and successively-lofted 7F is greater than 6°, and more specifically equal to 7.5°. Similarly, a difference in loft between the 7F and successively-lofted 9i is also no less than 6°, and more specifically equal to 9°. Thus, for a correlated set of irons of say seven or eight total clubs, a loft difference between two, more preferably three, even more preferably four, and most preferably all, successively-lofted clubs of the correlated set are greater than 6°. Preferably, in some embodiments, no iron-type club in the set 100 that has a loft between 15° and 45° has a difference in loft angle that is less than 5° from a successively lofted or successively numbered iron-type club in the set that has a loft angle between 15° and 45°.
Unlike a conventional set of iron-type golf clubs, correlated set of golf clubs 100 in FIG. 1 skips or omits certain lofts associated with conventional iron-type club designations, such as a conventionally designated six-iron club and a conventionally-designated eight-iron club, in favor of providing clubs with substantially equal lofts, but that differ with respect to at least one physical feature different from loft. In the example of FIG. 1, set 100 omits clubs with lofts corresponding to a conventional 6-iron club and a conventional 8-iron club that are typically included in a set of iron-type clubs in favor of providing a second 5-iron club and a second 7-iron club (i.e., having lofts substantially equal to the first 5-iron and 7-iron, respectively) that each differ from the substantially same lofted 5-iron club and 7-iron club, respectively, with regard to at least one physical feature. As discussed in more detail below with reference to FIGS. 2A and 2B, each of the second 5-iron club and the second 7-iron club differ from the first 5-iron club and the first 7-iron club with respect to multiple physical features to better suit hitting a ball from a different turf condition. This mode of variation, as described above, may provide more effective outcomes for certain classes of golfers, such as those with high handicaps or otherwise exhibiting high dispersion in shot distance.
In this regard, many golfers may not benefit much from having a set of clubs that provide ten to fifteen yard gaps between successively lofted clubs (e.g., a difference in the average distance hit by a player with an 8-iron club and a 9-iron club) if their shot dispersion or accuracy is not consistent enough to distinguish the distance gaps between shots hit with the successively lofted clubs. Thus, increasing gaps in loft between some, or all, successively-lofted club heads may serve to reduce the number of clubs a golfer may carry to effectively handle an appropriate overall range of shot distances. Yet, club carrying budget is thereby freed up for the golfer to carry clubs for purposes other than distance gapping. For example, a set of correlated golf clubs designed to provide twenty to twenty-five yard gaps between successively lofted clubs (e.g., between the 7F club and the 9-iron club in set 100) can enable the addition of clubs that vary in regards other than loft, i.e., may enable introduction of non-loft variant clubs to the correlated set. In the embodiment shown in FIG. 1, such non-loft variant clubs are introduced. As used herein, “non-loft variant” refers to a linear, areal, spatial or mass-related feature of a golf club that varies relative to a comparative golf club of a same set by at least 15% in absolute terms.
Specifically, substantially same lofted clubs are introduced that are designed for different turf conditions without increasing the overall number of clubs in the set, which allows for a similar cost, weight, and size of the correlated set of clubs as compared to a conventional set of correlated clubs.
The differences in physical features for the substantially same lofted clubs (e.g., five-irons 5T and 5F or seven-irons 7T and 7F in FIG. 1), i.e., a non-loft variant, can provide better suitability for different turf conditions. For example, five-iron 5T and seven-iron 7T may be more suitable for hitting a golf ball from a golf tee, while five-iron 5F and seven-iron 7F may be more suitable for hitting a golf ball from a fairway. In other implementations, non-loft variant clubs, e.g., substantially same lofted clubs in set 100, may have different physical features designed for interaction with different turf conditions than for a tee or fairway turf condition, such as for shorter or taller grass turf (e.g., fairway shots versus rough shots). For say a high handicapped golfer, having clubs with variation in turf adaptability may be ultimately more effective than a reduced loft increment between clubs of the set in reducing score.
Alternatively, or in combination with variation in adaptation for turf, non-loft variants may include, for example, different club lengths, different moments of inertia for the club heads, different sole contours of the bottoms of the club heads, different leading edge heights of the club heads, different club head volumes, different center of gravity heights for the club heads, different leading edge radii, different striking face surface areas, different striking face surface textures, different head masses, and different biasing, such as for draw or face, e.g., by different internal or external weighting, different face angle or other feature expected to result in varied right to left shot trajectory.
As shown in the example of FIG. 1, clubs 5F and 5T have different lengths from each other, and clubs 7F and 7T have different lengths from each other. The shorter club lengths for the 5F and 7F clubs in FIG. 1 can be better suited to a steeper angle of attack in a golf swing for hitting from the fairway as compared to a more upward or positive angle of attack for a golf swing for hitting from a tee. Preferably in such embodiments, the difference in club length between the 5F and 5T clubs and/or the difference in club length between the 7F and 7T clubs is no less than 0.5 in, and more preferably no less than 0.75 in. Additionally, or alternatively, the 5T and 7T clubs have club lengths greater than 37 in, and more preferably in the range of 37 in to 38 in, whereas, preferably, the 5F and 7F clubs have club lengths no greater than 37.5 in, and more preferably in the range of 36 in to 37.5 in.
In addition, clubs 5F and 5T have differently shaped and sized club heads from each other, and clubs 7F and 7T have differently shaped and sized club heads from each other. As discussed in more detail below with reference to FIGS. 2A and 2B, the club heads 10 and 30 for clubs 7F and 7T, respectively, can differ in that the striking face of club head 10 is smaller than the striking face of club head 30 with different grooves and/or surface textures. The center of gravity locations for club heads 10 and 30 in set 100 also differ due to different mass distributions in the club heads. As discussed in more detail below with reference to FIG. 2C, the locations of the centers of gravity for differently lofted clubs in set 100 can differ, such as the center of gravity locations for club heads 50 and 70 for the 9-iron club and pitching wedge club, but set 100 differs from conventional sets in some embodiments in that set 100 includes clubs with substantially equal lofts that have club heads with different center of gravity locations (e.g., the center of gravity locations for club heads 10 and 30). Additionally, or alternatively, the “T” clubs within set 100 may include striking faces having bulge and/or roll, e.g., at conventional radii of about 7 in to about 12 in, and more preferably of about 10 in, whereas the “F” clubs within set 100 have striking faces of substantially planar contour. Alternatively, both “F” and “T” clubs within the set 100 may include bulge and/or roll, but the “F” clubs may include bulges and/or rolls of respective radii greater than bulge/roll radii of their commensurate “T” counterparts.
The Moments of Inertia (MOIs) for the club heads about a vertical axis through the center of gravity can also differ in some embodiments for clubs in set 100 that have substantially equal lofts. In addition, the height and curvature of the leading edges of the striking faces can also differ, which can affect the bounce for each of the club heads as discussed in more detail below. Optionally, the mass of the club heads and/or the volume of the club heads may also differ to better suit different turf conditions.
Those of ordinary skill in the art will appreciate with reference to the present disclosure that other examples of correlated set of golf clubs 100 are possible. For example, other correlated sets can include a different number or arrangement of clubs, such as two 4-iron clubs or two 6-iron clubs, instead of two 5-iron clubs and two 7-iron clubs. As another example variation, other implementations may include additional iron-type clubs, such as a sand wedge, a gap wedge, or a lob wedge, or may not include a 4-iron club and/or a 5-iron club. In yet other examples, set of golf clubs 100 can include one or more other non-iron types of golf clubs, such as fairway woods, a driver, hybrid clubs, and/or a putter. In addition, those of ordinary skill in the art will appreciate with reference to the present disclosure that the clubs in set 100 in other implementations may have slightly varying loft angles for similarly indicated lofts than those depicted in FIG. 1. For example, a 4-iron club in other implementations may have a loft angle of 23° instead of the 21° loft angle indicated for the 4-iron club in FIG. 1.
FIG. 2A provides front views of the 7-iron club heads from correlated set of golf clubs 100 in FIG. 1 according to one or more embodiments. Club heads shown e.g. in FIGS. 2A through 2C are in reference position. As used herein, “reference position” denotes a position of a golf club head, e.g., the club head of FIG. 2A, in which a sole portion of the club head contacts a virtual ground plane such that a virtual central hosel axis of the hosel portion lies in a virtual vertical hosel plane and the score lines of the club head are oriented horizontally relative to the ground plane (or a horizontal imaginary line lying within a striking face plane is parallel with the virtual vertical hosel plane, in the case of a club head absent scorelines). Unless otherwise specified, all club head dimensions described herein are taken with the club head in the reference position.
As shown in FIG. 2A, club head 10 for the 7F-iron club has a smaller striking face 12 than striking face 32 for club head 30 of the 7T-iron club. The larger striking face 32 for hitting from a tee can provide a higher MOI for club head 30 and a larger sweet area (e.g., area of the striking face exhibiting a coefficient of restitution of at least 90% of a maximum coefficient of restitution of the striking face), which can provide for more “forgiveness” for off-center shots and greater overall shot distance. On the other hand, the smaller striking face 12 of club head 10 can allow the club head to move more easily through a turf condition providing more resistance, such as through a fairway or rough turf condition.
The surface textures of striking faces 12 and 32 also differ to impart different amounts of spin on the ball at contact and for removing more or less debris and/or moisture between the ball and the striking face at the point of impact. Striking face 12 for club head 10 has more grooves 14 to remove more moisture and debris from the point of contact with the ball, which is less of a concern for shots hit from a tee using club head 30. In fact, in some embodiments, the striking face of head 30 is absent any grooves or includes grooves of a depth not exceeding 0.1 mm. As discussed in more detail below with reference to FIG. 2B, the depths and shapes of grooves 14 and 34 can differ to remove more or less moisture and debris and to impart more or less spin on the ball at contact.
In addition, the surface textures of striking faces 12 and 32 may differ with respect to a surface roughness for increasing the friction between the ball and the striking face, which increases the amount of spin imparted onto the ball. The surface roughness on the striking face may be formed, for example, by etching or milling the surface of the striking face to result in different surface patterns. In some implementations, surface textures other than the grooves or score-lines may be orientated to promote or suppress different types of spin, such as to increase backspin without increasing sidespin. In the example of FIG. 2A, the 7-iron fairway or 7F club may have greater surface roughness, e.g., a higher average surface roughness Ra value and/or a higher peak-to-trough surface roughness value Rt, to increase the amount of spin imparted onto a ball at the point of impact to facilitate a higher flight trajectory, while the 7-iron tee or 7T club may have a smoother surface texture to impart less spin on the ball at the point of impact to facilitate a lower flight trajectory.
As shown in FIG. 2A, club heads 10 and 30 include indicia of “7F” and “7T”, respectively, on their striking faces. Since both the 7F and 7T clubs have substantially equal lofts, club heads 10 and 30 are identified with the same numeric designation of “7” for a 7-iron club but differ in the “F” and “T” alphabetical designation for fairway and tee, respectively. Those of ordinary skill in the art will appreciate with reference to the present disclosure that club heads 10 and 30 may include indicia of their loft and intended turf condition in other locations, such as on a toe-end of the sole of the club head. In addition, other implementations may include indicia for other turf conditions such as, “R” for a rough turf condition, or different numeric designations as with the “5F” and “5T” clubs included in correlated set 100 in FIG. 1 or a numeric designation indicating the loft angle of the club.
Club heads 10 and 30 also differ in that leading edge 18 of club head 10 is higher than leading edge 38 of club head 30 from virtual ground plane 8. In this regard, club heads 10 and 30 are orientated in FIG. 2A in a reference position with soles 16 and 36, respectively, in contact with virtual ground plane 8. In the reference position, club heads 10 and 30 are positioned at their designated loft angles of approximately 31° and at a predetermined lie angle.
As shown in FIG. 2A, the higher leading edge 18 of club head 10 in combination with the contour of sole 16 provides for a greater bounce as compared to the lower height of leading edge 38 and contour of sole 36 of club head 30. A bounce or bounce angle of a golf club head can be generally thought of as how much lower a trailing portion of a sole of the golf club head is than a leading edge of the sole, i.e., the degree to which the sole is inclined relative to a virtual ground plane. The bounce angle affects the amount of resistance the club head encounters from turf, soil, or sand when swinging the golf club to hit a golf ball and can be especially important regarding particular turf conditions. For example, a higher bounce angle can reduce the amount of resistance encountered when the golf ball is hit from looser ground surfaces, such as from soft sand or tall grass, to allow the club head to move more easily through the grass or sand.
In the example of FIG. 2A, club head 10 has a higher bounce angle for hitting a ball from grass on a fairway, while club head 30 has a lower bounce angle for hitting a ball from a tee. In addition, players may benefit from different bounce angles depending on, for example, the angle of attack or steepness of their swing toward the golf ball. For example, players with a shallow angle of attack in their swing may benefit from a lower bounce angle where the trailing portion of the sole is not much lower than a leading edge of the sole, while players with a steeper angle of attack in their swing may benefit from a higher bounce angle where the trailing portion of the sole is relatively lower. The steepness of the angle of attack may also vary for hitting from different turf conditions, such as from a fairway or from a tee.
FIG. 2A also depicts the center of gravity for the club heads 10 and 30 with center of gravity 20 and center of gravity 40, respectively. As shown in FIG. 2A, and further shown in the cross-section views of FIG. 2B, center of gravity 20 is located lower or closer to virtual ground plane 8 with a center of gravity height of HF than center of gravity 40, which has a greater center of gravity height HT that is farther from virtual ground plane 8. The lower center of gravity location of club head 10 for the fairway 7-iron club can enable higher dynamic loft or launch after impact, which may be beneficial for hitting a ball out of a grass turf condition as opposed to hitting a ball off of a tee. The higher center of gravity 40 of club head 30 can increase spin and can compensate for a higher position of the ball on a tee. The difference between HF and HT for center of gravity heights can result from more mass being located in a lower portion of club head 10 and/or more mass being located in an upper portion of club head 30.
A projection of the center of gravity, e.g., center of gravity 20 or 40, onto the striking face, as described herein, refers to the sweet spot of the striking face. Preferably, the sweet spot is aligned with the face center of the striking face of either, and preferably both, of the club heads 10 and 30. Because of the preferably larger striking face of club head 30, as described above, the height of face center of club head 30 from the ground plane is preferably greater than the height of the face center of the striking face of club head 10. Thus, the height of the sweet spot of the striking face of the club head 30 is preferably also greater than the height of the sweet spot of the striking face of club head 10. For this reason, as well as those above, the height of the center of gravity of club head 30 (i.e., HT) is greater than the height of the center of gravity of club head 10 (HF). Additionally, or alternatively, the sweet spot height of the club head 30 is preferably no less than 20 mm, more preferably within the range of 25 mm to 50 mm, and even more preferably within the range of 30 mm to 40 mm. Additionally, or alternatively, the height of the sweet spot of club head 10 is preferably less than 20 mm, and more preferably within the range of 10 mm to 18 mm. Additionally, or alternatively, the height of the sweet spot of club head 30 is greater than the height of the sweet spot of club head 10 by no less than 5 mm, more preferably no less than 10 mm, and even more preferably no less than 15 mm.
FIG. 2B provides cross-section views of the club heads of FIG. 2A taken along the cross-section lines labeled 2B in FIG. 2A. As shown in FIG. 2B, club head 10 has a wider sole 16 in a horizontal dimension (i.e., parallel to virtual ground plane 8) with more of a curved contour in a vertical dimension (i.e., perpendicular to virtual ground plane 8) than sole 36 of club head 30. Although the volume of club head 30 may be larger than that of club head 10, the mass of club head 30 may be about equal to or lower than that of club head 10. Preferably, the volume of club head 30 is no less than 250 cc, more preferably no less than 280 cc, even more preferably no less than 325 cc, and yet even more preferably no less than 375 cc. Additionally, or alternatively, the volume of club head 10 is no greater than 200 cc, and preferably between about 80 cc and 175 cc. Additionally, or alternatively, the volume of club head 30 is greater than the volume of club head 10 by no less than 75 cc, more preferably no less than 100 cc, and even more preferably no less than 125 cc.
As discussed above, the bounce angle θF of club head 10 is greater than the bounce angle θT of club head 30. The bounce angle can be measured in a virtual vertical plane intersecting a virtual striking face plane defined by the striking face and passing through the face center of the golf club head. The virtual sole line can be defined by a line passing through the leading edge of the sole and a ground contact point where the sole contacts the virtual ground plane when orientated in the reference position. The bounce angle θF of club head 10 in FIG. 2B is determined by the angle between virtual sole line 26 and virtual ground plane 8 and the bounce angle θT of club head 30 is determined by the angle between virtual sole line 46 and virtual ground plane 8. Virtual sole line 26 is defined by the line between ground contact point 24 and leading edge 18, while virtual sole line 46 is defined by the line between ground contact point 44 and leading edge 38. As shown in FIG. 2B, sole 16 has a greater curvature for helping club head 10 move through a grass turf condition as compared to sole 36 of club head 30 which does not need to move through a grass turf condition when hitting a ball from a tee.
In addition, the radius of leading edge 18 of club head 10 is more curved or has a larger radius than the radius of leading edge 38 of club head 30. This can better suit club head 10 to a fairway turf condition, as compared to club head 30 for hitting a ball from a tee where interaction with grass is less of a concern. The larger radius of leading edge 18 can also increase the bounce of club head 10 as compared to club head 30.
The example of FIG. 2B also shows IzzF and IzzT representing MOIs about respective vertical axes extending through their corresponding centers of gravity. A higher MOI can make the golf club more forgiving in terms of hitting off-center shots by providing a larger sweet spot on the striking face. In this regard, the MOI IzzT for club head 30 can be greater than the MOI IzzF for club head 10 of the 7F fairway club to allow for more off-center shots, which may result more frequently when hitting from a tee. In some implementations, IzzT may be no less than about 3400 g·cm2. In some cases, Izzy may be no less than 4000 g·cm2. In even more extreme cases, IzzT may be no less than 5000 g·cm2. IzzF is preferably no greater than 3000 g·cm2, and more preferably, between about 1500 g·cm2 and 2600 g·cm2. Additionally, or alternatively, IzzT is greater than IzzF by at least 500 g·cm2, more preferably 1200 g·cm2, and even more preferably 2000g·cm2.
As shown in FIG. 2B, grooves or score-lines of club head 10, such as groove 141 are wider and more numerous with a larger U-shape, as compared to the narrower and less numerous V-shape grooves or score-lines of club head 30, such as groove 341. The shape of the grooves of club head 10 may be formed to move more debris and moisture from the surface of striking face 12, which is better suited for hitting from a grass turf condition. Club head 30 may not need as many or as deep of grooves since it is intended to hit a ball from a tee and therefore can impart better spin on the ball with less grooves.
In addition to the higher location of center of gravity 40 of club head 30 from virtual ground plane 8 (i.e., HT is greater than HF in FIG. 2B), center of gravity 40 is also located farther behind striking face 32 at a perpendicular distance DT, as compared to the location of center of gravity 20 of club head 10 behind striking face 12 at a perpendicular distance DF. The farther distance from striking face 32 of center of gravity 40 can make shots with club head 30 more forgiving and increase spin on the ball, which can improve shot control. In particular, the center of gravity of golf club head 30 preferably has a depth DT from the striking face of no less than 20 mm, more preferably no less than 25 mm, and even more preferably within the range of 25 mm to 35 mm. Additionally, or alternatively, the center of gravity of the golf club head 10 preferably has a depth no greater than 20 mm, more preferably no greater than 15 mm, and even more preferably within the range of 4 mm to 15 mm. Additionally, or alternatively, the depth of the center of gravity of the club head 30 is greater than the depth of the center of gravity of the club head 10 by no less than 10 mm, more preferably no less than 15 mm, and even more preferably no less than 15 mm. Adapting a golf club head for impacting a golf ball on a tee may free up design space in a manner that enables, for example, a larger sole expanse, a greater volume, and a more selective placement of internal and/or external weight pads or thickened regions. Accordingly, providing a non-loft variant club head specifically adapted for hitting off of a tee may ultimately provide better overall results for golfers that may benefit less from a smaller loft increment across club heads of a correlated set.
As noted above, the different mass distributions for club heads 10 and 30 can position the centers of gravity in different locations, such as different heights HF and HT from virtual ground plane 8 and different depths DF and DT from the striking face, to make shots from the club more forgiving and/or to compensate for different amounts of spin or launch imparted on the ball at impact. For example, by providing a wider sole 16 for the fairway turf condition as compared to the narrower width of sole 36 for the tee turf condition, more mass of club head 10 is located closer to virtual ground plane 8, which results in a lower location of center of gravity 20 as compared to the location of center of gravity 40. The higher launch caused by this lower location of center of gravity 20 may therefore be somewhat offset by a closer center of gravity position to striking face 12 with DF, which can lower the launch of a ball when hit by club head 10.
FIG. 2C provides cross-section views of club heads 50 and 70 from correlated set of golf clubs 100 in FIG. 1 according to one or more embodiments. As shown by club heads 50 and 70 in FIG. 2C, the lofts for the 9-iron and the pitching wedge clubs from set 100 differ with respect to virtual ground plane 8 when the clubs are orientated in the reference position. Notably, the locations of center of gravities 60 and 80 for club heads 50 and 70, respectively, differ in that the perpendicular distance D9 of center of gravity 60 from striking face 52 is less than the perpendicular distance DP of center of gravity 80 from striking face 72. The perpendicular distance of the center of gravity behind the striking face may increase across a correlated set of golf clubs as the loft of the club increases to provide for a higher launch and more spin for more control of shorter shots. However, unlike a conventional correlated set of golf clubs, correlated set of golf clubs 100 includes clubs that have substantially equal lofts with club heads having different center of gravity depths to accommodate different turf conditions.
FIG. 3 is a flowchart for a process of forming a correlated set of golf clubs according to one or more embodiments. The process of FIG. 3 may be performed, for example, by a golf club manufacturer in manufacturing a correlated set of golf clubs, such as correlated set of golf clubs 100 with at least two clubs having substantially equal, or optionally equal, loft but differing from each other with respect to at least one physical feature. In some embodiments, no fewer than two, more preferably, no fewer than three, and even more preferably no iron-type club in the set that has a loft between 15° and 45° has a difference in loft angle less than five degrees from a successively numbered iron-type club in the set with a loft angle between 15° and 45°.
In block 302, a first club head is formed including shaping the first club head for interaction with a first turf condition with a loft of L1 that is between 15° and 45°. In the case of an iron-type club, the first club head may be formed by, for example, a forging process or a casting process using a metallic material. The shaping of the first club head for the first turf condition (e.g., a fairway turf condition) can include, for example, a sole contour, a sole width, a leading edge height for the sole, a leading edge radius for the sole, a center of gravity location (e.g., height and/or distance from the striking face), a striking face surface area, a striking face surface texture, and/or a club head mass.
In block 304, a second club head is formed including shaping the second club head for interaction with the first turf condition. The second club head is also formed so that it is successively lofted relative to the first club head with a loft L2 between 15° and 45° and being greater than L1 by at least 5°, and more preferably at least 6°. As used herein, successively lofted refers to the club having an immediately next greater loft angle than a previous club in the correlated set. Shaping the second club head for interaction with the first turf condition can include sharing one or more of the same physical features used to shape the first club head for interaction with the first turf condition, such as, sharing a similar sole contour, sole width, leading edge height, leading edge radius, center of gravity location, striking face surface area, striking face surface texture, and/or club head mass.
In block 306, a third club head is formed including shaping the third club head for interaction with the first turf condition. The third club head is also formed so that it is successively lofted relative to the second club head with a loft L3 between 15° and 45° and being greater than L2 by at least 5°, and more preferably at least 6°. Shaping the third club head for interaction with the first turf condition can include sharing one or more of the same physical features used to shape the first and second club heads for interaction with the first turf condition, such as, sharing a similar sole contour, sole width, leading edge height, leading edge radius, center of gravity location, striking face surface area, striking face surface texture, club head mass, and/or club head volume.
In block 308, a fourth club head is formed including shaping the fourth club head for interaction with a second turf condition, such as for hitting from a tee, hitting from a rough, or hitting from a loose soil, such as sand. Notably, the loft of the fourth club head is formed to be substantially equal to one of L1, L2, or L3 for the loft of the first club head, the second club head, or the third club head, respectively. Although the fourth club head may be formed using a similar process as that for the first, second, and third club heads, such as by a forging process or a casting process, the fourth club head is shaped differently from the substantially equally lofted first, second, or third club head. In this regard, shaping the fourth club head for interaction with the second turf condition can include providing a different physical feature from the first, second, or third club head, such as, a different sole contour, sole width, leading edge height, leading edge radius, center of gravity location (e.g., height and/or distance from the striking face), striking face surface area, striking face surface texture, club head mass, and/or club head volume.
Those of ordinary skill in the art with reference to the present disclosure will appreciate that the process of FIG. 3 may include additional steps or may form part of a larger process, such as assembling the club heads formed in blocks 302 to 308 with respective shafts and grips for the different clubs in the correlated set.
The embodiments described above, as well as others contemplated, may be further described with reference to loft plots, such as those shown in FIGS. 4A through 4D. Each of these loft plots illustrates the loft placement of clubs within exemplary correlated sets (i.e., respective correlated sets I through IV) including illustrating the placement of such lofts being presented in non-loft variant clubs versus standard clubs of the correlated set (i.e., those clubs not containing the particular non-loft variant). As described above, in general, by increasing increment of loft of standard clubs of the set, fewer standard clubs are necessary to fulfill an acceptable range of lofts, thereby freeing up club quota for additional clubs that may vary in a non-negligible manner in a mode primarily other than loft, e.g., adaptability for hitting off a tee versus off fairway or turf. The embodiments described above with regard to FIGS. 1 through 2C may be considered to introduce duplicative irons, i.e., irons in the same set that bear identical or nearly identical loft but at least one containing a non-loft variant. However, extensions of this and other variations are possible.
For example, referring to FIG. 4C, a correlated set of iron-type golf clubs, i.e., correlated set III, is shown. In this particular embodiment, duplicative-lofted clubs are presented. In some embodiments, only a single pair of clubs of a set may be loft-duplicative. However, in other cases, more than one pair, such as two or three pairs of clubs may be loft-duplicative. For example, as shown, for correlated set III, a loft difference between some pairs of successively-lofted clubs are relatively small, such as for the 9i and PW clubs and for the 7i and 8i clubs. However, some pairs of successively-lofted clubs exhibit a relatively large increment in loft, such as between the 5i and 7i clubs, as well as between the 7i and 9i clubs. These large loft gaps free up club quota for non-loft variant (NLV) clubs. Accordingly, NLV golf clubs are presented, such as the 3i-T, the 5i-T, and the 7i-T clubs. In this particular embodiment, it is contemplated that the 3i-F, 5i-F, and 7i-F clubs, as well as the remaining non-suffixed golf clubs have shapes and properties configured for hitting off fairway or turf. In contrast, the 3i-T, 5i-T, and 7i-T clubs have shapes and properties configured for hitting off a tee. It is understood that such a non-loft variant may be replaced or augmented with other non-loft variants, for example, any of those described above with regard to the embodiments of FIGS. 1 through 2C, while adhering to the same or similar loft plot scheme illustrated.
Referring to FIG. 4A, an alternative correlated set, correlated set I, is shown with reference to a loft plot. In this particular case, non-loft variant clubs are introduced to the correlated set using a staggered loft approach in place of the duplicative loft approach of the correlated set III of FIG. 4C. In the example of FIG. 4A, some clubs are modified from standard to contain one or more non-loft variants. For example, the 3i, 5i and 7i through PW clubs are configured for hitting off fairway or turf. However, the 4i and 6i clubs are configured instead for hitting off a tee. Thus, the golfer in selecting a club for use off a fairway must still contend with higher loft increments, such as between the 3i and 5i clubs and between the 5i and 7i clubs.
In FIG. 4B, an exemplary correlated set of iron-type clubs are shown, i.e., correlated set II. In this case, a hybrid staggered-duplicative loft approach is illustrated. For example, irons 7i-T and 7i-F share the same, or nearly identical loft so as to be a duplicative loft, with the 7i-T club being a non-loft variant golf club. Yet, the 4i club is a staggered non-loft variant golf club. A relatively large loft gap is presented between the 3i and 5i clubs (i.e., about) 6°, and the NLV 4i club has a loft between that of the 3i and 5i clubs.
In FIG. 4D, an alternative correlated set, correlated set IV, is shown with reference to a loft plot. In this case, no particular or discernible golf club designation is removed from the standard portion of the correlated set. Instead, the number of standard clubs is reduced from 8 to 7 over the same overall loft range (e.g. between 21° to 48°), and the remaining clubs are evenly dispersed in loft over the same overall range. In this case, the clubs may not have lofts that precisely follow conventional designation. For example, one or more clubs may benefit from indicia including half or mixed designations (e.g. the 5i/6i club designation as shown). This may result in confusion for some golfers. However, a benefit is presented in that no particularly large loft gaps are presented between any pair of successively-lofted golf clubs of the set. In this case, optionally, the increment in loft between successively-lofted clubs may be constant across all standard clubs. Alternatively, the increment of loft may vary progressively, either linearly, exponentially, stepwise, or otherwise. For example, the loft increment may gradually decrease in progressing from lower-lofted clubs to higher-lofted clubs. This may be beneficial as precision in shot distance may be considered more critical at distances closer to the pin. A non-loft variant club head is presented, which may be duplicative of a loft of a standard golf club or staggered from lofts of standard golf clubs of the correlated set IV. In this case, the NLV club is shown to be slightly staggered in loft from the standard 7i and to have a loft of about 35°, which may be considered to be, and bear indicia of, a 7i or 7i/8i club. Also in this case, the NLV club corresponds to a club configured to hit off a tee, whereas the standard clubs of this set are configured for hitting off fairway or turf.
The foregoing examples of sets of correlated clubs can provide clubs that are better suited for different turf conditions without increasing the overall number of clubs added to the correlated set by replacing certain successively lofted clubs included in conventional sets with clubs having a loft substantially equal to another club in the correlated set but tailored to a different turf condition. This can ordinarily improve play for a wider variety of turf conditions without increasing the number of clubs that need to be purchased or carried and without greatly affecting the gaps in shot dispersion, especially for less advanced players who may not hit the ball consistently enough to notice a difference in distance between successively lofted clubs in a conventional set.
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 of correlated sets may include different clubs that have lofts that are substantially equal other than the examples of 7-irons and 5-irons provided above for set 100. Similarly, other correlated sets may include additional clubs or different types of clubs, such as a driver or a putter. 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. The described embodiments are to be considered in all respects only as illustrative and not restrictive. 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.”
Patent Application
20250170460
