Patent Application
20160250532
This application relates to golf clubs, and more particularly to wedges.
Golf is a game in which a player, choosing from a variety of different golf clubs, seeks to hit a ball into each hole on the golf course in the fewest possible strokes. A wedge is one type of golf club, and is designed for hitting short, precise shots onto a green, hitting high-lofted shots, and for hitting shots from difficult lies, such as from tall grass or from a sand bunker. In some wedge shots, the head of a wedge may travel through turf, sand, or other materials prior to striking the ball. When swinging a wedge, it is desirable to maintain a smooth, stable stroke to provide optimal accuracy and precision.
Described below are embodiments of wedges and other iron-type golf clubs that are counterbalanced with significant mass located near the butt of the shaft above the grip location. Additional mass may also be added to the club head compared to a conventional club head. In the disclosed golf clubs, the club head and the butt end of the club can have increased mass compared to an analogous conventional club, which provides an increase in overall total mass, an increase in the moment of inertia about the CG of the club (MOICG), while maintaining a balance about the hand grip fulcrum location that provides a similar swingweight compared to a conventional club. The increase in club head mass and MOICG compared to a conventional club of similar style can provide increased swing stability during a stroke, decreasing unintentional waggling about the hand grip fulcrum, and thus providing increased accuracy and precision to wedge shots. The increase in club head mass and MOICG can also help the club head travel through soil, grass, sand, etc., with more momentum and less interruption, providing more consistent and accurate ball striking. The familiar swingweight of the disclosed clubs compared to conventional clubs makes the disclosed club feel familiar to a golfer and therefore the disclosed clubs can be readily playable in place of a conventional club without the golfer having to significantly change his swing.
The foregoing and other objects, features, and advantages of the disclosed technology will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.
Disclosed herein are embodiments of wedges and other golf iron-type clubs that are counterbalanced with a counterbalance weight located at or near the upper end or “butt end” of the shaft above the gripping location. As used herein, the terms “wedge” and “wedge-type golf club” mean any iron-type golf club having a static loft angle that is greater than 45°. Any of the disclosure described herein in relation to a wedge or wedge-type golf club can be embodied in any of various wedges having different loft angles, such as a pitching wedge, gap wedge, sand wedge, lob wedge, flop wedge, and/or wedges having static loft angles of 46°, 48°, 50°, 52°, 54°, 56°, 58°, 60°, greater than 60°, and any other angles greater than 45°. The disclosed technology can also be embodied in iron-type golf clubs having static loft angles of 45° or less, such as a 9-iron or lower-numbered irons.
In disclosed embodiments, the club head and the butt end of the shaft have increased mass compared to a conventional club of the same loft and style. Such clubs can have an increased overall total mass as compared to a conventional club of similar type, and can have an increase in the moment of inertia (MOI) of the club about the CG and/or about the hand grip fulcrum location (e.g., where the club pivots when a golfer rotates his hands/wrists). The increase in MOI can provide increased swing stability during a swing stroke, decreasing unintentional waggling about the CG and hand grip fulcrum, and thus providing increased accuracy and precision to shots. In addition, the increase in MOI, and in particular the increase provided by the added mass in the club head, can provide greater momentum and stability as the club head travels through turf, sand, or other material, leading to less disruption of the path, orientation, and velocity of the club head.
At the same time, the added weight in the club head and the added weight in the butt end of the shaft can counterbalance each other in such a way that the overall swingweight of the club (e.g., rotational moment about the hand grip fulcrum location due to gravity) can be about the same as for a conventional, non-counterbalanced club having significantly less total mass. Having the same or similar swingweight can provide the golfer a familiar feel and sensation during a swing that makes the disclosed clubs readily playable in place of a conventional club without having to adjust one's swing.
Club Swingweight
The moment of inertia (MOI) of a wedge or other iron-type golf club can be determined based on a selected axis perpendicular to the shaft. The MOI about a given axis provides a measure of the club's inertial resistance to rotating about that axis. For example, the MOI of the club 10 about an axis extending perpendicular to the shaft axis (e.g., perpendicular to the page in
Calculating the true MOI of a club about any axis can be difficult. One method of calculating the MOI of a club about a selected axis is by measuring the undamped period of oscillation of the club while it is fixed to a torsional spring of a testing machine at a point where the selected axis intersects the shaft axis, with the torsional spring being aligned with the selected axis. The overall MOI of the system (club plus torsional spring fixture) can then be calculated using the formula MOI=(k*T2)/(4π2), where “k” is the coefficient of the torsional spring, and T is the undamped period of oscillation of the whole system. The MOI of the club about the selected axis is then equal to the overall MOI of the system minus the MOI of the torsional spring fixture by itself. Thus, the MOI of the club about the selected axis can be calculated as MOIclub=(k/4π2)*(T2−(Tfixt)2), where “Tfixt” is the period of oscillation of the torsional spring fixture by itself without a club fixed to it. Tfixt can be a known value for a given MOI testing system. Using such a testing system and method, the MOI of the club about any axis intersecting the shaft can be calculated, such as the MOICG or the MOIe.
MOI values for a club can also be approximated, such as by assuming the mass of the shaft and grip are negligible and representing the club head as a point mass at the center of the head. The MOI about a given axis perpendicular to and intersecting the shaft axis can then be approximated as the mass of the club head multiplied by the square of the distance from the center of the head to the given axis. This is illustrated in
The MOIe of the club 50 can be approximated as the sum of the inertial effect of the head 52 and the inertial effect of the counterbalance weight 57. As described above, the inertial effect of the head 52 can be approximated as N2*X12, where “N2” is the mass of the head 52. Similarly, the inertial effect of the counterbalance weight 57 can be approximated as N3*X22, where “N3” is the mass of the counterbalance weight 57 and “X2” is the distance from the center 66 of the counterbalance weight to the grip fulcrum point 62, as shown in
The MOICG of the club 50 can be approximated in a similar manner using analogous dimensions from the mass centers 64 and 66 to the CG. The MOIe and MOICG of the club 50 will therefore be greater than the MOIe and MOICG of the club 10 if the mass of their heads are equal or if the mass of the head 52 of club 50 is greater than the mass of the head 12 of club 10. The greater MOIe and/or greater MOICG of the club 50 can provide greater swing stability during a swing and can make it more difficult for a golfer to accidentally adjust the swing path of the club when it is in motion, giving the golfer more consistent, predictable ball striking. This also gives the club head more inertial resistance while traveling through turf, sand, or other material prior to striking the ball, thereby maintaining swing speed and swing path.
While an increase in MOIe and/or MOICG is desirable, it can also be desirable to increase the mass of the club head and/or maintain the same or similar swingweight compared to a conventional club 10. To add mass to the club head 52 and add mass to the butt end of the club in the form of the counterbalance weight 57, it may be desirable to subtract mass from elsewhere in the club so the club does not become too heavy and feel awkward to the golfer. For example, the mass of the shaft and/or the mass of the grip can be reduced to accommodate the added mass of a counterbalance weight and the added mass in the club head. In some embodiments, a lightweight shaft can be used instead of a conventional shaft. For example, the shaft can comprise substantially all graphite and/or other lightweight materials. In another example, a bi-matrix shaft can be used that comprises graphite and/or other lightweight material in an upper portion and steel and/or other strong, plastically deformable material in a lower portion or tip portion to allow the tip portion to be plastically bent to adjust the orientation of the head relative to the shaft axis. The grip can also be comprised of lightweight material and/or can be reduced in volume to reduce its mass contribution to the club. By reducing the mass of the shaft and/or grip, more mass can be added to the club head and counterbalance weight without making the club overly heavy.
The counterbalance weight 57 can comprise any dense material, can have any shape, and can be coupled to the shaft and/or grip in any manner. In some embodiments, the counterbalance weight can be adjustable and/or removable. In some embodiments, two or more counterbalance weights can be provided to allow a user to select which one to couple to the club. For example, the different counterbalance weights can have different masses, different shapes, different lengths, and/or different aesthetic appearances. A person may be able to remove one weight from the shaft and attach another weight to the shaft to change the characteristics of the club. In some embodiments, two or more counterbalance weights may be attached to the club at the same time, such as one on top of the other or side-by-side, etc. For example, a first weight may attach to the shaft and a second weight may attach to the first weight. In some embodiments, the different weights can appear identical, but have different masses (e.g., different materials and/or hollow regions). In some embodiments, the counterbalance weights can require a tool to be removed from the club or to be secured to the club, while in other embodiments no tool is required. When attached to the club, the counterbalance weights may be non-adjustable or may be adjustable.
In embodiments where a counterbalance weight is adjustable when attached to the club, the axial position of the counterbalance weight relative to the shaft and/or grip may be adjusted. For example, the counterbalance weight may be adjustable along the shaft axis by rotating the counterbalance weight relative to the shaft. A threaded attachment with the shaft may be used, for example. In some embodiments, the positional adjustability can be limited to a group of discrete positional settings, rather than a continuous or analog range of positions. In such embodiments, the weight can be fixable at each of the discrete positional settings, such as by using a tool to tighten a set screw, or the like.
A counterbalance weight can have a radial outer surface that is substantially contiguous with and/or blends into the radial outer gripping surface of the grip, such that a smooth transition is formed at an annular joint 78 (see
In any of the embodiments disclosed herein, the counterbalance weight can have any axial length, provided the width and density of it are sufficient to provide the desired mass addition to the butt end of the club. In some circumstances, it may be undesirable for the butt end of a club to extend too far above the golfer's hands. For example, rules may prohibit the butt end of the club from contacting or being anchored to the golfer's torso or other body portion other than the hands. Further, the butt end of the club may undesirably contact the golfer's legs or other body part during a swing if it projects too far above the golfer's hands. Thus, a shorter counterbalance weight can be desirable. To provide a maximum mass per axial length added to the club, the counterbalance weight can be made wider (e.g., as wide as the grip or wider) and can be made from a relatively dense material, such as steel, tungsten, or other dense metals. In some embodiments, the axial length of the counterbalance weight is less than four inches, less than 3 inches, less than 2 inches, and/or less than 1 inch. The overall length “L2” of a counterbalance wedge-type clubs as described herein including a counterbalance weight can be less than or equal to 40 inches, less than or equal to 39 inches, less than or equal to 38 inches, less than or equal to 37 inches, and/or less than or equal to 36 inches.
The mass added to the club head 52 can be added in any manner. In some embodiments, one or more adjustable and/or removable weights can be coupled to the club head. Such weights may be removable and interchangeable with other weights having different masses. In other embodiments, the size and/or materials of the club head may be changed to increase the mass of the club head a desired amount.
The disclosed counterbalanced clubs can have any overall mass, though in some embodiments the overall mass of the club, including any weights, can be at least about 400 grams, at least about 450 grams, at least about 475 grams, at least about 500 grams, and/or at least about 525 grams.
The counterbalance weight(s) itself can also have any mass, though in some embodiments the mass of the counterbalance weight is at least about 25 grams, at least about 40 grams, at least about 50 grams, at least about 70 grams, and/or at least about 100 grams.
The mass of the club head can be, for example, at least about 280 grams, at least about 300 grams, at least about 310 grams, at least about 320 grams, and/or at least about 340 grams.
The mass added to the club head, whether in the form of one or more weights movable relative to the head body or increased mass of the head body, can be at least 5 grams, at least 8 grams, at least 10 grams, and/or at least 15 grams. In one particular example, the club head has a total mass of about 309 grams, including added mass in the form of one or more weights that have a mass of about 9 grams, while the counterbalance weight has a mass of about 50 grams.
The shaft can have any mass, such as 130 grams or less, 100 grams or less, 80 grams or less, 70 grams or less, and/or 60 grams or less. In one particular example, a bi-matrix shaft is included that has a graphite upper portion with a mass of about 50 grams and a steel lower portion with a mass of about 20 grams, providing a total of about 70 grams.
The grip can also have any mass, such as 100 grams or less, 50 grams or less, 40 grams or less, and/or 35 grams or less. In some embodiments, the grip comprises a lightweight EVA material.
The total mass of the shaft and grip together can be lower than in a conventional club, such as less than 200 grams, less than 150 grams, less than 125 grams, less than 110 grams, and/or less than 100 grams.
The disclosed counterbalance clubs can have any MOICG, such as at least 500 kg*cm2, at least 525 kg*cm2, at least 550 kg*cm2, at least 575 kg*cm2, at least 600 kg*cm2, and/or at least 625 kg*cm2. Similarly, the disclosed counterbalance clubs can have any MOIe (with e=30 inches), such as at least 2000 kg*cm2, at least 2025 kg*cm2, at least 2050 kg*cm2, at least 2075 kg*cm2, at least 2100 kg*cm2 and/or at least 2200 kg*cm2.
Another meaningful parameter type for counterbalanced golf clubs are ratios of a club moment of inertia divided by the club length squared (L2). For example, the ratio MOICG per unit length2 (in units of kg*cm2/inch2) for the disclosed counterbalance clubs can be from about 1.4:1 to about 1.1:1, from about 1.35:1 to about 1.15:1, and/or from about 1.3:1 to about 1.2:1.
Yet another meaningful parameter for counterbalanced golf clubs are ratios of a club moment of inertia divided by the total club mass. For example, the ratio MOICG per unit mass (in units of kg*cm2/g) for the disclosed counterbalance clubs can be at least 1.05, at least 1.10, at least 1.15, at least 1.20, and or at least 1.23.
Still another meaningful parameter type for counterbalanced clubs is the ratio of the MOICG per unit length2 divided by the total club mass. This parameter can be expressed in terms of a unitless percentage and can be referred to as “inertial efficiency” since it represents how effectively the mass and length of the club are utilized to maximize the MOICG. The disclosed counterbalance clubs can have an inertial efficiency of at least 13%, at least 13.3%, at least 13.5%, at least 13.8%, at least 14.0%, at least 14.2%, at least 14.4%, at least 14.6%, at least 14.8%, and/or at least 15.0%.
The disclosed counterbalance clubs can have a swingweight that is similar to a conventional club of the same type having less mass. For example, the disclosed counterbalance clubs can have a swingweight (with e=30 inches) of less than 3.0 N*m, less than 2.8 N*m, less than 2.7 N*m, greater than 2.6 N*m, greater than 2.64 N*m, greater than 2.68 N*m, between 2.5 N*m and 3.0 N*m, between 2.6 N*m and 2.8 N*m, between 2.63 N*m and 2.75 N*m, and/or between 2.66 N*m and 2.70 N*m.
Table 1 below provides representative data for two different exemplary wedges. Wedge A is an exemplary embodiment of the counterbalanced clubs described herein, having a 58° loft. Wedge B is an exemplary conventional wedge having the same 58° loft and same general style as Wedge A, but without a counterbalance weight at the butt end of the shaft and less club head mass. As shown in Table 1, Wedge A is slightly longer than Wedge B due to the counterbalance weight added to the butt end of the shaft. Wedge A also has a greater mass, greater MOICG, and greater inertial efficiency than Wedge B. However, Wedges A and B have about the same swingweight.
As shown in
The components of the embodiments disclosed herein can be formed from any of various suitable metals, metal alloys, polymers, composites, or various combinations thereof.
In addition to those noted elsewhere herein, examples of metals and metal alloys that can be used to form the components include, without limitation, carbon steels (e.g., 1020 or 8620 carbon steel), stainless steels (e.g., 304 or 410 stainless steel), PH (precipitation-hardenable) alloys (e.g., 17-4, C450, or C455 alloys), titanium alloys (e.g., 3-2.5, 6-4, SP700, 15-3-3-3, 10-2-3, or other alpha/near alpha, alpha-beta, and beta/near beta titanium alloys), aluminum/aluminum alloys (e.g., 3000 series alloys, 5000 series alloys, 6000 series alloys, such as 6061-T6, and 7000 series alloys, such as 7075), magnesium alloys, copper alloys, nickel alloys, and tungsten.
Examples of composites that can be used to form the components include, without limitation, glass fiber reinforced polymers (GFRP), carbon fiber reinforced polymers (CFRP), metal matrix composites (MMC), ceramic matrix composites (CMC), and natural composites (e.g., wood composites).
Examples of polymers that can be used to form the components include, without limitation, thermoplastic materials (e.g., polyethylene, polypropylene, polystyrene, acrylic, PVC, ABS, polycarbonate, polyurethane, polyphenylene oxide (PPO), polyphenylene sulfide (PPS), polyether block amides, nylon, and engineered thermoplastics), thermosetting materials (e.g., polyurethane, epoxy, and polyester), copolymers, and elastomers (e.g., natural or synthetic rubber, EPDM, and Teflon®).
In view of the many possible embodiments to which the principles of the disclosed technology may be applied, it should be recognized that the illustrated embodiments are only examples and should not be taken as limiting the scope of the disclosure. Rather, the scope of the disclosure is at least as broad as the following exemplary claims. We therefore claim all that comes within the scope of the following claims.
