The present invention relates to golf balls, and more particularly, to golf balls having improved surface patterns. More specifically, the present invention relates to golf balls having variable width/depth ridges or channels on the golf ball surface.
Golf balls generally include a spherical outer surface with a plurality of dimples formed thereon. Conventional dimples are circular depressions that reduce drag and increase lift. These dimples are formed where a dimple wall slopes away from the outer surface of the ball forming the depression.
Drag is the air resistance that opposes the golf ball's flight direction. As the ball travels through the air, the air that surrounds the ball has different velocities, thus different pressures. The air exerts maximum pressure at a stagnation point on the front of the ball. The air then flows around the surface of the ball with an increased velocity and reduced pressure. At some separation point, the air separates from the surface of the ball and generates a large turbulent flow area behind the ball. This flow area, which is called the wake, has low pressure. The difference between the high pressure in front of the ball and the low pressure behind the ball slows the ball down. This is the primary source of drag for golf balls.
The dimples on a traditional golf ball cause a thin boundary layer of air adjacent to the ball's outer surface to flow in a turbulent manner. Thus, the thin boundary layer is called a turbulent boundary layer. The turbulence energizes the boundary layer and helps move the separation point further backward, so that the boundary layer stays attached further along the ball's outer surface. As a result, there is a reduction in the area of the wake, an increase in the pressure behind the ball, and a substantial reduction in drag. It is the circumference of each dimple, where the dimple wall drops away from the outer surface of the ball, which allows dimples to create the turbulence in the boundary layer.
Lift is an upward force on the ball that is created by a difference in pressure between the top of the ball and the bottom of the ball. This difference in pressure is created by a warp in the airflow that results from the ball's backspin. Due to the backspin, the top of the ball moves with the airflow, which delays the air separation point to a location further backward. Conversely, the bottom of the ball moves against the airflow, which moves the separation point forward. This asymmetrical separation creates an arch in the flow pattern that requires the air that flows over the top of the ball to move faster than the air that flows along the bottom of the ball. As a result, the air above the ball is at a lower pressure than the air underneath the ball. This pressure difference results in the overall force, called lift, which is exerted upwardly on the ball. The circumference of each dimple is important in optimizing this flow phenomenon, as well.
By using dimples to decrease drag and increase lift, almost every golf ball manufacturer has increased their golf ball flight distances. In order to improve ball performance, it is desirable to have a large number of dimples, hence a large amount of dimple circumference. In arranging the dimples, an attempt is made to minimize the space between dimples, because such space does not improve aerodynamic performance of the ball. In practical terms, this usually translates into 300 to 500 circular dimples with a conventional sized dimple having a diameter that typically ranges from about 0.100 inches to about 0.180 inches.
When compared to one conventional size dimple, theoretically, an increased number of small dimples will create greater aerodynamic performance by increasing total dimple circumference. However, in reality small dimples are not always very effective in decreasing drag and increasing lift. This results at least in part from the susceptibility of small dimples to paint flooding. Paint flooding occurs when the paint coat on the golf ball fills the small dimples, and consequently decreases the dimple's aerodynamic effectiveness.
Golf ball manufacturers continue to search for more efficient methods of changing the surface of a golf ball in order to improve the aerodynamics or to impart unique aerodynamic properties to golf balls.
The present invention is directed to a golf ball with improved surface patterns. More specifically, the present invention relates to golf balls having a system of variable width and/or height/depth ridges or channels on the golf ball surface. Preferably, the depth of the deepest portions of the ridges or channels may be from about 0.005 inches to about 0.030 inches, more preferably from about 0.010 inches to about 0.020 inches. Preferably, the width of the widest points of the ridges or channels may be from about 0.050 inches to about 0.250 inches, more preferably from about 0.100 inches to about 0.200 inches.
The present invention is further directed to a golf ball comprising a substantially spherical outer surface and a channel system comprising one or more variable width and/or depth channels formed thereon. The channels of the present invention may be straight or curved, may or may not circumscribe the golf ball. The channels may also be discontinuous. The channels may or may not intersect other channels. They may cover as much of the ball surface as desired, up to virtually 100%, but preferably the surface coverage of the channels is less than about 40%, preferably less than about 30%, or less than about 20% or less than about 10%. The lower percentages are more preferable in cases where the channels are combined with other types of surface texture such as conventional dimples.
In some embodiments, these channels may allow the golf ball to have orientation-specific aerodynamic properties, i.e., to fly differently depending on its orientation when hit off of a tee. In other embodiments, the channels allow the ball to have greater flight symmetry. In some embodiments, there may be both channels and dimples or other features on the surface of the golf ball.
In yet another preferred embodiment, a golf ball can be formed with an outer surface having a channel surface pattern system. The channel surface pattern is formed of at least one channel defined on the outer surface. The channel surface pattern system covers from about 5% to about 40% of the outer surface. Preferably, the edge angle of the at least one channel ranges from about 16° to about 90° and the at least one channel surrounds or forms a plurality of spherical polygonal tiles.
In one of the preferred embodiments, the outer surface further comprises a plurality of dimples disposed within the spherical polygonal tiles and the dimples cover about 40% to about 90% of the outer surface of the ball. Preferably, the channel(s) and the dimples together cover about 60% to about 100% of the outer surface. Even more preferably, the channel(s) and the dimples together cover about 70% to about 90% of the outer surface, where the channel(s) covers from about 5% to about 20% of the outer surface. The dimples formed in the spherical polygonal tiles can be circular dimples, polygonal dimples or other desired shapes.
Preferably, the edge angle of the at least one channel is relatively large. More specifically, it is preferred that the edge angle of the channel is greater than the edge angle of the dimples. For example, the edge angle of the channel can range from about 18° to about 40°, and more preferably, the edge angle of the channel ranges from about 20° to about 30°. Whereas, the edge angles of the dimples are preferably less than 20° and even more preferably less than 18°.
In a preferred embodiment, the outer surface is comprised of between about 90 to about 400 spherical polygonal tiles surrounded by a continuous channel. The spherical polygonal tiles are preferably formed into a polyhedral layout. Each of the spherical polygonal tiles may include at least one dimple formed therein, and preferably, each of the spherical polygonal tiles includes a plurality of at least two dimples formed therein. For example, at least some of the tiles are preferably hexagons that further include either six triangular dimples, three diamond-shaped dimples or two trapezoidal dimples formed therein. Similarly, pentagon shaped tiles can include triangular or trapezoidal dimples as well. On the other hand hexagonal tiles may include a plurality of up to seven circular dimples and pentagonal shaped tiles may include up to six circular dimples.
In one embodiment, it is preferred that the channel surface pattern system comprises a plurality of channels that do not intersect each other and form a plurality of spherical polygonal tiles on the outer surface. Each of the tiles may contain one or more concentric channels therein. For example, the plurality of channels can form hexagonal tiles with multiple, non-intersecting channels therein. Similarly, the plurality of channels can form hexagonal and pentagonal tiles that are strategically arrange over the surface of the ball to provide symmetric aerodynamic properties.
Further features and advantages of the invention can be ascertained from the following detailed description that is provided in connection with the drawings described below:
In one embodiment as illustrated in
As seen in
Preferably, bands 12 have a depth or height which varies along their length by between about 0.002 inches and about 0.025 inches. More preferably bands 12 have a depth or height which varies along their length by between about 0.005 inches and about 0.015 inches. Preferably, bands 12 have a depth or height at their deepest or highest points of at least about 0.005 inches and less than about 0.030 inches. More preferably, bands 12 have a depth or height at their deepest or highest points of at least about 0.010 inches and less than about 0.020 inches. Preferably, bands 12 have a width which varies along their length by between about 0.005 inches and about 0.245 inches. More preferably, bands 12 have a width which varies along their length by between about 0.010 inches and 0.195 inches. Preferably, bands 12 have a width at their widest points of at least about 0.050 inches and less than about 0.250 inches. More preferably, bands 12 have a width at their widest points of at least about 0.100 inches and less than about 0.200 inches.
Generally, it can be difficult to define and measure the width, depth or height, and edge angle of an irregular band due to the relative change in the depth or height due to the shape of the band as compared to the uninterrupted curvature of the ball.
Referring to
As shown in
Channels 14 may comprise a large percentage of the ball surface, but in accordance with one aspect of the present invention, they preferably comprise about 40% or less of the ball surface, more preferably about 30% or less, about 20% or less or about 10% or less. The lower percentages are more preferable in cases where the channels are combined with other types of surface texture such as conventional dimples. The combination of a relatively low coverage of the ball surface, i.e., about 40% or less, and relatively steep edge angle, i.e., about 16° or more, provides a unique aerodynamic package for golf ball 10 of the present invention that cannot be achieved with conventional circular dimples alone.
Preferably, channels 14 have an edge angle that is steeper than edge angles for conventional circular dimples. In one example, channels 12 have substantially the same depth as conventional circular dimples, but have a width that is significantly less than the diameter of conventional circular dimples, causing the edge angle to be steeper than the edge angle of conventional circular dimples, which typically ranges from 12°-16°. The edge angle of channels 12 is preferably greater than about 16°, more preferably greater than about 18°, and more preferably greater than about 20°. The edge angle can range from about 16° to about 90°, preferably from about 18° to about 40°, and more preferably from about 20° to about 30°. Referring to
One advantage of having relatively low surface coverage is that golf ball 10 behaves more like a true sphere and less like a faceted object when putting. This results in a truer direction of departure from the putter face, and a truer roll along the ground. This would be advantageous to all golfers, but especially to highly skilled golfers who will enjoy the full benefit of their putting skills because of the reduced influence of randomness.
However, it may be desirable to include dimples, bumps, pimples (inverted dimples), or other surface textures on the golf ball surface in addition to the channels. The dimples may be circular, or may have non-circular perimeters such as oval, hour-glass shape, regular and irregular polygons. Accordingly, the dimples may be triangular, rectangular, pentagonal, hexagonal, or any other suitable polygonal shape or non-polygonal shapes, or may have polygonal and non-polygonal portions. Another advantage of the present invention is that bands 12 having a variable width provide more efficient demarcation lines or groupings of both traditional and non-traditional dimples. Exemplary non-traditional dimples include the surface textures and band systems shown in
The channels are combined with dimples to increase the percentage of golf ball surface covered in dimples and channels to a level comparable to or greater than traditional golf balls. In one example, the surface coverage of bands 12 is in between about 5% to about 40% and the dimple coverage can be from about 40% to about 90%, with a total dimple/band coverage ranging from about 60% to 100%. More preferably, the total dimple/band coverage ranges from about 70% to 90%, and most preferably from about 75% to 85%. The synergistic combination of traditional dimples and a variable width band can be seen in
In another embodiment, as seen in
In another embodiment of the invention, a network of grooves or channels is formed on the surface of the ball, delineating a large number of spherical polygonal areas or tiles. Any technique may be used to arrange the grooves, but it is preferable to use a polyhedron such as an octagon, icosahedron, cuboctahedron, or a dodecahedron as the basis for the general layout. In a conventional dimple pattern, dimples would be arranged within the polygonal faces of the polyhedron and along their edges. In the present invention, a polyhedral layout is superimposed on the spherical surface and channels are formed at the edges of the spherical polygonal tiles.
Another example of an aerodynamic configuration composed of polygonal tiles separated by channels is shown in
The cross-sectional shape of the channels or grooves 32 is not particularly limited; however, generally V-, U-, and arc shaped cross-sections as set forth in more detail above are preferred. The specific dimensions of the cross-section, such as the width, the depth, and the wall angles are selected to create the desired performance characteristics. However, as mentioned above, it is preferred that the edge angle of the channels is about 16° to about 90°. In the embodiment set forth in
In another embodiment as set forth in
Still further, the cross-sectional shape of the dimples is not particularly limited. In
In yet another embodiment as set forth in
The present invention can also comprise a larger number of smaller dimples.
The configuration of channels 32 and dimples 48 of the ball 30 in
In these embodiments, there are preferably between about 90 and about 400 spherical tiles 34 defined by the channels 32. The channel surface pattern system 32 covers from about 5% to about 40% of the outer surface. Preferably, the edge angle of the at least one channel ranges from about 16° to about 90° and the at least one channel 32 surrounds or forms a plurality of spherical polygonal tiles. The plurality of dimples disposed within the spherical polygonal tiles cover about 40% to about 90% of the outer surface of the ball. Preferably, the channel(s) and the dimples together cover about 60% to about 100% of the outer surface. Even more preferably, the channel(s) and the dimples together cover about 70% to about 90% of the outer surface, where the channel(s) covers from about 5% to about 20% of the outer surface.
Referring to
The dimple arrangement of the present invention has an aerodynamic coefficient magnitude defined by Cmag=√(CL2+CD2) and an aerodynamic force angle defined by Angle=tan−1(CL/CD), wherein CL is a lift coefficient and CD is a drag coefficient. Further discussions of aerodynamic coefficient magnitude preferred for the present invention can be found in U.S. Pat. No. 7,156,757, which is incorporated herein by reference in its entirety.
While it is apparent that the illustrative embodiments of the invention disclosed herein fulfill the objectives of the present invention, it is appreciated that numerous modifications and other embodiments may be devised by those skilled in the art. Additionally, feature(s) and/or element(s) from any embodiment may be used singly or in combination with other embodiment(s) and steps or elements from methods in accordance with the present invention can be executed or performed in any suitable order. Therefore, it will be understood that the appended claims are intended to cover all such modifications and embodiments, which would come within the spirit and scope of the present invention.
This application is a continuation-in-part of U.S. patent application Ser. No. 12/356,632, filed on Jan. 21, 2009, and a continuation-in-part of U.S. patent application Ser. No. 12/233,649, filed on Sep. 19, 2008, which is itself a continuation in part of 11/025,952, filed on Jan. 3, 2005 and issued as U.S. Pat. No. 7,588,505. U.S. patent application Ser. No. 12/356,632 is also a continuation-in-part of U.S. patent application Ser. No. 12/061,779, filed on Apr. 3, 2008 and issued as U.S. Pat. No. 7,867,109, which is a continuation-in-part of U.S. patent application Ser. No. 11/141,093, filed on May 31, 2005 and issued as U.S. Pat. No. 7,455,601, which is a divisional of U.S. patent application Ser. No. 10/077,090 filed on Feb. 15, 2002 and issued as U.S. Pat. No. 6,905,426. These applications and patents are all incorporated by reference herein in their entireties.
Number | Date | Country | |
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Parent | 10077090 | Feb 2002 | US |
Child | 11141093 | US |
Number | Date | Country | |
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Parent | 12356632 | Jan 2009 | US |
Child | 13238355 | US | |
Parent | 12233649 | Sep 2008 | US |
Child | 12356632 | US | |
Parent | 11025952 | Jan 2005 | US |
Child | 12233649 | US | |
Parent | 12061779 | Apr 2008 | US |
Child | 12356632 | US | |
Parent | 11141093 | May 2005 | US |
Child | 12061779 | US |