Progressive Grooves in Golf Club Heads

The present invention relates to golf clubs. In particular, the present invention relates to golf club heads having improved striking surfaces. The striking surfaces include grooves having certain cross-sectional profiles based on the loft of the golf club head.

Golf club heads come in many different forms and makes, such as wood- or metal-type, iron-type (including wedge-type club heads), utility- or specialty-type, and putter-type. Each of these styles has a prescribed function and make-up.

Iron-type and utility-type golf club heads generally include a front or striking face, a top line, and a sole. The front face interfaces with and strikes the golf ball. A plurality of grooves, sometimes referred to as “score lines,” is provided on the face to assist in imparting spin to the ball. The top line is generally configured to have a particular look to the golfer and to provide structural rigidity for the striking face. A portion of the face may have an area with a different type of surface treatment that extends fractionally beyond the score line extents. Some club heads have the surface treatment wrap onto the top line. The sole of the golf club is particularly important to the golf shot because it contacts and interacts with the ground during the swing.

In conventional sets of iron-type golf clubs, each club includes a shaft with a club head attached to one end and a grip attached to the other end. The club head includes a face for striking a golf ball. The angle between the face and a vertical plane is called the loft angle.

An important aspect of golf is to be able to produce a desired amount of spin on the golf ball. It is also desirable to have predictable spin levels for each club within a set of clubs. Typically, higher lofted clubs in a set will produce more spin. Hitting shots out of longer grass (the “rough”) or in wet conditions can cause a significant reduction in spin resulting in unpredictable ball flight and inconsistent carrying distances. The magnitude of spin reduction is more prevalent in higher lofted clubs which can lead to “fliers” or the ball traveling further than anticipated which is a problem when trying to land the ball on the green at a specific distance.

Additionally, overly aggressive groove profiles can result in excessive spin which may adversely affect ball flight and the interaction between the ball and the turf upon landing. A need exists to create a set of golf clubs which can produce desired spin levels throughout the set when played in varying course conditions.

The present invention relates to golf club heads which solve the issues described above. In particular, the present invention relates to a set of golf club heads having improved groove profiles for different ranges of loft angles. The present invention includes at least a first set of golf club heads which are intended for the lower swing speed golfer and a second set of golf club heads which are intended for the higher swing speed golfer. The first set of golf club heads includes at least two different groove profiles: one groove profile for golf club heads with loft angles of 28 degrees or less, and a different groove profile for golf club heads with loft angles of greater than 28 degrees. The first set of golf club heads have groove profiles which are designed to help golfers generate more spin regardless of the lie condition while staying within certain desired spin levels when hitting out of poor conditions. The second set of golf club heads also includes at least two different groove profiles: one groove profile for golf club heads with loft angles of 31 degrees or less, and a different groove profile for golf club heads with loft angles of greater than 31 degrees. The second set of golf club heads have groove profiles which are less aggressive than the first set of golf club heads because the higher swing speed golfer can typically generate sufficient ball spin through technique. However, the second set of golf club heads has a groove profile in the higher lofted golf club heads that balances the desire for reducing spin loss out of the rough or in wet conditions with the desire to prevent imparting too much spin out of the fairway or in dry conditions.

In one aspect, the techniques described herein relate to a set of golf clubs, including: a first golf club head including: a striking face including a front surface configured to strike a golf ball; a body extending rearward from the striking face and having a sole, a topline opposite the sole, a heel side, a toe side opposite the heel side, and a hosel at the heel side configured to attach to a shaft; and at least one groove in the striking face extending in a heel-to-toe direction; a second golf club head including: a striking face including a front surface configured to strike a golf ball; a body extending rearward from the striking face and having a sole, a topline opposite the sole, a heel side, a toe side opposite the heel side, and a hosel at the heel side configured to attach to a shaft; and at least one groove in the striking face extending in a heel-to-toe direction, wherein the first golf club head has a loft angle less than or equal to 28 degrees, wherein the second golf club head has a loft angle greater than 28 degrees, and wherein the at least one groove of the first golf club head has a cross-sectional profile different than a cross-sectional profile of the at least one groove of the second golf club head.

In one aspect, the techniques described herein relate to a set of golf clubs, including: a first golf club head including: a striking face including a front surface configured to strike a golf ball; a body extending rearward from the striking face and having a sole, a topline opposite the sole, a heel side, a toe side opposite the heel side, and a hosel at the heel side configured to attach to a shaft; and at least one groove in the striking face extending in a heel-to-toe direction; a second golf club head including: a striking face including a front surface configured to strike a golf ball; a body extending rearward from the striking face and having a sole, a topline opposite the sole, a heel side, a toe side opposite the heel side, and a hosel at the heel side configured to attach to a shaft; and at least one groove in the striking face extending in a heel-to-toe direction, wherein the first golf club head has a loft angle less than or equal to 31 degrees, wherein the second golf club head has a loft angle greater than 31 degrees, and wherein the at least one groove of the first golf club head has a cross-sectional profile different than a cross-sectional profile of the at least one groove of the second golf club head.

The present invention is directed to a set of golf club heads having different groove profiles for different loft ranges. In one embodiment, a set of golf club heads includes at least a first golf club headhaving a loft less than or equal to 28 degrees and at least a second golf club headhaving a loft greater than 28 degrees at a normal address position. In another embodiment, a set of golf club heads includes at least a first golf club headhaving a loft less than or equal to 31 degrees and at least a second golf club headhaving a loft greater than 31 degrees at a normal address position.

show a first golf club headand a second golf club headof a set of golf clubs according to one embodiment of the present invention. The first golf club headincludes a bodydefining a striking face, a sole, a toplineopposite the sole, a heel side, a toe sideopposite the heel side, and a hoselat the heel sideconfigured to attach to a shaft (not shown). The striking faceincludes a front surfaceconfigured to strike a golf ball and at least one groove. The striking facemay be unitary with the body, or it may be a separate component, such as an insert, coupled to the body. The first golf club headhas a loft angle less than or equal to 28 degrees. The second golf club headincludes a bodydefining a striking face, a sole, a toplineopposite the sole, a heel side, a toe sideopposite the heel side, and a hoselat the heel sideconfigured to attach to a shaft (not shown). The striking faceincludes a front surfaceconfigured to strike a golf ball and at least one groove. The striking facemay be unitary with the body, or it may be a separate component, such as an insert, coupled to the body. The second golf club headhas a loft angle greater than 28 degrees.

shows a cross-sectional view of the first golf club headalong the at least one groove. The at least one groovemay be machined into the front surfaceof the striking face. The at least one grooveextends in a heel-to-toe direction of the first golf club head. The at least one grooveis shallow at both the toe and heel portions of the first golf club headand are deep in the central regions. The at least one groovehas a first distance Lmeasured along the front surfaceof striking faceand a second distance Lmeasured along the deepest portion of the at least one groove. Thus, the first distance Lis an overall distance and the second distance Lis a maximum depth distance. In one embodiment the second distance Lis at least 0.2 inches shorter than the first distance L.

The at least one groovemay be radiused at the toe and heel portions of the first golf club headand may be machined into the striking face. The first golf club headis retained in a mold, which preferably is formed of a material soft enough to not damage the first golf club headyet resilient enough to firmly retain the first golf club head. A cutter, preferably a round cutter or a saw cutter, may be used to form the at least one groove. As shown, the toe and heel portions are radiused about an axis of rotation that is perpendicular to a longitudinal axis of the at least one groove. Furthermore, that axis of rotation is approximately parallel to the striking faceof the first golf club head. Preferred cutters have a diameter from ⅜ inch to ¾ inch. A preferred range of groove radii include from 0.125 inch to 5 inches, with 0.25 inch to 2.5 inches being more preferred. Having radiused grooves facilitates removal of dirt, grass, sand, and other materials that typically become embedded within grooves of a golf club during normal use by eliminating corners that can trap these materials.shows a preferred groove cutting setup illustrating the cutterwith the at least one groove.

shows a cross-sectional view of at least one grooveof the first golf club head. The at least one grooveincludes a first sidewall, a second sidewall, a bottom wallbetween the first sidewalland the second sidewall, a first edgebetween the first sidewalland the front surfaceof the striking face, and a second edgebetween the second sidewalland the front surfaceof the striking face. The at least one grooveis symmetrical about a longitudinal planelocated equidistant from the first sidewalland the second sidewalland extending perpendicular to the front surfaceof the striking face. The first edgeand the second edgeare each curved and have an edge radius R. The at least one grooveincludes a width Wbetween the first edgeand the second edge. The bottom wallis spaced a depth Dfrom the front surfaceof the striking face. The at least one grooveincludes a wall angle θdefined between the first sidewalland the longitudinal plane.

The at least one grooveof the first golf club headincludes a wall angle θbetween 24 degrees and 32 degrees, more preferably between 26 degrees and 30 degrees, and most preferably about 28 degrees. The wall angle is critical to ball spin generation because it affects the amount that the groove sidewalls interact with the ball and affects the angle at which the edges of the groove impact the ball. The at least one grooveof the first golf club headhas a depth Dbetween 0.010 inches and 0.016 inches, more preferably between 0.013 inches and 0.015 inches, and most preferably about 0.014 inches. The depth of the groove is a critical factor in the amount of moisture and debris the ball gets exposed to during a shot while also maintaining the structural rigidity of the striking face. The at least one grooveof the first golf club headhas a width Wbetween 0.025 and 0.030 inches, more preferably between 0.027 inches and 0.029 inches, and most preferably about 0.028 inches. The width of the groove affects the spin imparted to the ball by determining the amount of contact area the ball experiences with the front surface of the striking face, the amount the ball may compress between edges of the groove, and the number of grooves that ultimately interact with the ball during the shot. Additionally, the at least one grooveof the first golf club headhas a first edgeand a second edgeeach with an edge radius Rbetween 0.005 inches and 0.009 inches, more preferably between 0.006 inches and 0.008 inches, and most preferably about 0.007 inches. The edge radius, in conjunction with the wall angle, is critical to ball spin generation because it determines the amount of grab that the edges of the groove impart on the ball.

In a preferred embodiment, the set of golf clubs includes at least three golf club heads having a loft angle less than or equal to 28 degrees and having the same cross-sectional groove profile as described above for the first golf club head.

shows a cross-sectional view of at least one grooveof the second golf club head. The at least one grooveof the second golf club headhas a different cross-sectional profile than the at least one grooveof the first golf club head. The at least one grooveof the second golf club headincludes a first sidewall, a second sidewall, a bottom wallbetween the first sidewalland the second sidewall, a first edgebetween the first sidewalland the front surfaceof the striking face, and a second edgebetween the second sidewalland the front surfaceof the striking face. The at least one grooveis symmetrical about a longitudinal planelocated equidistant from the first sidewalland the second sidewalland extending perpendicular to the front surfaceof the striking face. The first edgeand the second edgeare each curved and have an edge radius R. The at least one grooveincludes a width Wbetween the first edgeand the second edge. The bottom wallis spaced a depth Dfrom the front surfaceof the striking face. The at least one grooveincludes a wall angle θdefined between the first sidewalland the longitudinal plane.

The wall angle θof the at least one grooveof the second golf club headis less than the wall angle θof the at least one grooveof the first golf club head. The depth Dof the at least one grooveof the second golf club headis greater than the depth Dof the at least one grooveof the first golf club head.

In one embodiment, the at least one grooveof the second golf club headincludes a wall angle θbetween 16 degrees and 24 degrees, more preferably between 18 degrees and 22 degrees, and most preferably about 20 degrees. The at least one grooveof the second golf club headhas a depth Dbetween 0.015 inches and 0.020 inches, more preferably between 0.016 inches and 0.018 inches, and most preferably about 0.017 inches. In this embodiment, the width Wof the at least one grooveof the second golf club headis greater than the width Wof the at least one grooveof the first golf club head. The at least one grooveof the second golf club headhas a width Wbetween 0.028 and 0.034 inches, more preferably between 0.029 inches and 0.033 inches, and most preferably about 0.031 inches. Additionally, the at least one grooveof the second golf club headhas a first edgeand a second edgeeach with an edge radius Rbetween 0.005 inches and 0.009 inches, more preferably between 0.006 inches and 0.008 inches, and most preferably about 0.007 inches.

In another embodiment, the at least one grooveof the second golf club headincludes a wall angle θbetween 10 degrees and 18 degrees, more preferably between 12 degrees and 16 degrees, and most preferably about 14 degrees. The at least one grooveof the second golf club headhas a depth Dbetween 0.016 inches and 0.020 inches, more preferably between 0.017 inches and 0.019 inches, and most preferably about 0.018 inches. In this embodiment, the width Wof the at least one grooveof the second golf club headis less than the width Wof the at least one grooveof the first golf club head. The at least one grooveof the second golf club headhas a width Wbetween 0.024 and 0.028 inches, more preferably between 0.025 inches and 0.027 inches, and most preferably about 0.026 inches. Additionally, the at least one grooveon the second golf club headhas a first edgeand a second edgeeach with an edge radius Rbetween 0.006 inches and 0.010 inches, more preferably between 0.007 inches and 0.009 inches, and most preferably about 0.008 inches.

In a preferred embodiment, the set of golf clubs includes at least three golf club heads having a loft angle greater than 28 degrees and having the same cross-sectional groove profile as described above for the second golf club head.

show a first golf club headand a second golf club headof a set of golf clubs according to another embodiment of the present invention. The first golf club headincludes a bodydefining a striking face, a sole, a toplineopposite the sole, a heel side, a toe sideopposite the heel side, and a hoselat the heel sideconfigured to attach to a shaft (not shown). The striking faceincludes a front surfaceconfigured to strike a golf ball and at least one groove. The striking facemay be unitary with the body, or it may be a separate component, such as an insert, coupled to the body. The first golf club headhas a loft angle less than or equal to 31 degrees. The second golf club headincludes a bodydefining a striking face, a sole, a toplineopposite the sole, a heel side, a toe sideopposite the heel side, and a hoselat the heel sideconfigured to attach to a shaft (not shown). The striking faceincludes a front surfaceconfigured to strike a golf ball and at least one groove. The striking facemay be unitary with the body, or it may be a separate component, such as an insert, coupled to the body. The second golf club headhas a loft angle greater than 31 degrees.

shows a cross-sectional view of at least one grooveof the first golf club head. The at least one grooveincludes a first sidewall, a second sidewall, a bottom wallbetween the first sidewalland the second sidewall, a first edgebetween the first sidewalland the front surfaceof the striking face, and a second edgebetween the second sidewalland the front surfaceof the striking face. The at least one grooveis symmetrical about a longitudinal planelocated equidistant from the first sidewalland the second sidewalland extending perpendicular to the front surfaceof the striking face. The first edgeand the second edgeare each curved and have an edge radius R. The at least one grooveincludes a width Wbetween the first edgeand the second edge. The bottom wallis spaced a depth Dfrom the front surfaceof the striking face. The at least one grooveincludes a wall angle θdefined between the first sidewalland the longitudinal plane.

The at least one grooveof the first golf club headincludes a wall angle θbetween 30 degrees and 45 degrees, more preferably between 34 degrees and 41 degrees, and most preferably about 37.5 degrees. The at least one grooveof the first golf club headhas a depth Dbetween 0.012 inches and 0.019 inches, more preferably between 0.014 inches and 0.018 inches, and most preferably about 0.016 inches. The at least one grooveof the first golf club headhas a width Wbetween 0.028 and 0.034 inches, more preferably between 0.029 inches and 0.033 inches, and most preferably about 0.031 inches. Additionally, the at least one grooveof the first golf club headhas a first edgeand a second edgeeach with an edge radius Rbetween 0.0025 inches and 0.0075 inches, more preferably between 0.0035 inches and 0.006 inches, and most preferably about 0.0047 inches.

In a preferred embodiment, the set of golf clubs includes at least three golf club heads having a loft angle less than or equal to 31 degrees and having the same cross-sectional groove profile as described above for the first golf club head.

shows a cross-sectional view of at least one grooveof the second golf club head. The at least one grooveof the second golf club headhas a different cross-sectional profile than the at least one grooveof the first golf club head. The at least one grooveof the second golf club headincludes a first sidewall, a second sidewall, a bottom wallbetween the first sidewalland the second sidewall, a first edgebetween the first sidewalland the front surfaceof the striking face, and a second edgebetween the second sidewalland the front surfaceof the striking face. The at least one grooveis symmetrical about a longitudinal planelocated equidistant from the first sidewalland the second sidewalland extending perpendicular to the front surfaceof the striking face. The first edgeand the second edgeare each curved and have an edge radius R. The at least one grooveincludes a width Wbetween the first edgeand the second edge. The bottom wallis spaced a depth Dfrom the front surfaceof the striking face. The at least one grooveincludes a wall angle θdefined between the first sidewalland the longitudinal plane.

The wall angle θof the at least one grooveof the second golf club headis less than the wall angle θof the at least one grooveof the first golf club head. The depth Dof the at least one grooveof the second golf club headis greater than the depth Dof the at least one grooveof the first golf club head.

The at least one grooveof the second golf club headincludes a wall angle θbetween 16 degrees and 24 degrees, more preferably between 18 degrees and 22 degrees, and most preferably about 20 degrees. The at least one grooveof the second golf club headhas a depth Dbetween 0.015 inches and 0.020 inches, more preferably between 0.016 inches and 0.018 inches, and most preferably about 0.017 inches. The at least one grooveof the second golf club headhas a width Wbetween 0.028 and 0.034 inches, more preferably between 0.029 inches and 0.033 inches, and most preferably about 0.031 inches. Additionally, the at least one grooveof the second golf club headhas a first edgeand a second edgeeach with an edge radius Rbetween 0.005 inches and 0.01 inches, more preferably between 0.006 inches and 0.009 inches, and most preferably between 0.007 inches and 0.008 inches.

In a preferred embodiment, the set of golf clubs includes at least three golf club heads having a loft angle greater than 31 degrees and having the same cross-sectional groove profile as described above for the second golf club head.

A set of golf clubs utilizing the groove combinations of the present invention as described above better maintains proper ball spin progression throughout the set when hitting shots from a variety of turf and moisture conditions.

Other than in the operating examples, or unless otherwise expressly specified, all of the numerical ranges, amounts, values and percentages such as those for amounts of materials, moments of inertias, center of gravity locations, loft and wall angles, and others in the following portion of the specification may be read as if prefaced by the word “about” even though the term “about” may not expressly appear with the value, amount, or range. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Furthermore, when numerical ranges of varying scope are set forth herein, it is contemplated that any combination of these values inclusive of the recited values may be used.

While the preferred embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not of limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus the present invention should not be limited by the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.