Patent Application
20230372779
The present disclosure relates to golf balls, particularly to golf balls including dimples having ridged and/or textured surfaces. More particularly, the present disclosure relates to golf balls including dimples constructed of radial channels.
Aerodynamic forces generated by a golf ball in flight are a result of its velocity and spin. These forces can be represented by a lift force and a drag force. Lift force is perpendicular to the direction of flight and is a result of air velocity differences above and below the rotating ball. This phenomenon is attributed to Magnus, who described it in 1853 after studying the aerodynamic forces on spinning spheres and cylinders, and is described by Bernoulli's Equation, a simplification of the first law of thermodynamics. Bernoulli's equation relates pressure and velocity where pressure is inversely proportional to the square of velocity. The velocity differential, due to faster moving air on top and slower moving air on the bottom created by the ball's spin, results in lower air pressure on top and an upward directed force on the ball.
Drag is opposite to the direction of flight and orthogonal to lift. The overall drag force on a ball is pressure drag and viscous or skin friction drag. A sphere is a bluff body, which is a somewhat inefficient aerodynamic shape. As a result, the accelerating flow field around the golf ball causes a large pressure differential with high-pressure forward and low-pressure behind the ball. The low-pressure area behind the ball is also known as the wake. In order to minimize pressure drag, dimples provide a means to energize the flow field and delay the separation of flow, or reduce the wake region behind the ball.
The industry has seen many efforts to improve the aerodynamic efficiency of golf balls, such as through variations in dimple configuration, dimple pattern, and other methods. For example, dimple properties such as number, shape, size, volume, edge angles and overall pattern have been manipulated in an attempt to generate a golf ball that has improved aerodynamic properties. A further consideration that may not be as thoroughly developed is the surface configuration and texture of the dimples themselves. Dimple surfaces can be adjusted and adapted to include non-smooth textures to introduce new air flow patterns and further refine the aerodynamic properties of the ball. The present disclosure relates to a development in surface texturing of a golf ball dimples to augment aerodynamic performance.
In one embodiment, the present disclosure describes a golf ball. The golf ball includes a generally spherical surface and a plurality of dimples separated by a land area formed on the surface. At least one of the dimples includes a perimeter edge connected to the land area and a dimple surface surrounded by the perimeter edge. The dimple surface defines a dimple point depth in relation to a phantom surface that is a continuation of the land area. The dimple surface includes a plurality of channels and a plurality of channel edges. At least one of (i) the plurality of channels or (ii) the plurality of channel edges extend continuously from the perimeter edge to an intersection at a dimple center. Each channel is defined by a portion of the dimple surface between a first edge of the plurality of channel edges and a second edge of the plurality of channel edges. The dimple surface further defines a channel point depth in relation to the first and second edges. Each channel includes a first area having a plan shape of a circular sector of a channel circle. The first and second edges are edges of the circular sector and extend radially from the dimple center to a terminal end at the channel circle. The perimeter edge intersects the channel circle only at terminal ends of the plurality of channel edges.
In another embodiment, the present disclosure describes another golf ball. The golf ball includes generally spherical surface and a plurality of dimples separated by a land area formed on the surface. At least one of the dimples comprises a perimeter edge connected to the land area and a dimple surface surrounded by the perimeter edge. The dimple surface defines a dimple point depth in relation to the land area and includes a plurality of channels radiating from a dimple center. The dimple surface further includes a plurality of channel edges separating the channels. The dimple point depth continuously increases from the perimeter edge to the dimple center along all radii of a dimple circle that circumscribes the perimeter edge.
In another embodiment, the present disclosure describes a method of manufacturing a golf ball. The method includes forming a golf ball having a generally spherical surface. The generally spherical surface includes a plurality of dimples separated by a land area formed on the surface. At least one of the dimples comprises a perimeter edge connected to the land area and a dimple surface surrounded by the perimeter edge. The dimple surface defines a dimple point depth in relation to the land area and includes a plurality of channels radiating from a dimple center. The dimple surface further includes a plurality of channel edges separating the channels. The dimple point depth continuously increases from the perimeter edge to the dimple center along all radii of a dimple circle that circumscribes the perimeter edge.
In the accompanying drawings which form a part of the specification and are to be read in conjunction therewith and in which like reference numerals are used to indicate like parts in the various views:
The aerodynamic characteristics of a golf ball are largely dependent on the dimples present on the outer surface. Golf balls typically include 250-500 dimples on the outer surface that range from about 0.080-0.200 in. in diameter (or effective diameter, if non-circular). The arrangement of these dimples on the outer surface (i.e., the “dimple pattern”), the dimple shapes, the edge angles, the cross-sectional profiles, the depths, etc., all contribute to the overall flight performance of the golf ball. Dimple surface configuration and texture is another characteristic that affects the aerodynamic performance because the interaction between the dimple surface and the surrounding air affects the overall drag characteristics. For example, surface texture may be introduced to enhance aerodynamics
The present disclosure includes a golf ball including dimples having a ridged/textured surface. For example, in an embodiment, a disclosed dimple includes a plurality of radially-arranged channels connected around the dimple center. The channels may include at least a portion that is in the shape of a circular sector. For example, the channels may appear in a plan view as a pie chart with “pie slices” arranged around the center. The channels may additionally have a second portion that connects the circular sector to the surrounding land area of the golf ball. For example, the arc portion of the circular sector may be connected to a curved entrance zone that has an edge flush with the land area of the golf ball. Each radial channel may be connected to two adjacent radial channels at channel edges. The channel edges extend from the dimple center to the dimple perimeter edge. The channels and channel edges, which alternate in a circumferential direction (i.e., in a circle around the dimple center 20) around the dimple, make up an entirety of the surface of the dimple.
In an exemplary embodiment, the perimeter edge 16 is non-circular and includes a scalloped edge shape that alternates between rounded peaks and pointed valleys in a plan view. The pointed valleys are connected to the terminal ends 24 of the channel edges 22. The scalloped edge shape of the perimeter edge accommodates an entrance zone into the plurality of channels 18 without an abrupt edge angle.
The dimple center 20 may be a point at an intersection of the plurality of channels 18 and/or the plurality of channel edges 22. As will be described, the channel edges 22 approach the dimple surface 17 at the dimple center 20. In this way, it can be considered that at least one of (i) the plurality of channels 18 or (ii) the plurality of channel edges 22 extend continuously from the perimeter edge 16 to an intersection at the dimple center 20. For instance, the dimple center 20 may be considered a combination of channels 18 coming together at one point, a combination of the tops of channel edges 22 intersecting at one point, or both.
In another aspect, the dimple center 20 may be considered the point in the plan view that corresponds to the centroid of the dimple 12 (which may coincide with the center of the dimple circle DC). In
In
In the dimple 12, the channel circle CC divides each channel 18 into a first area 42 and a second area 44 (shown for example with respect to channels 26, 28 in
The dimple surface 17 in the second area 44 is situated between the perimeter edge 16 and the channel circle CC. The second area of the first channel 26 is bounded by the segment 46 of the channel circle CC and a portion 50 of the perimeter edge 16. The portion 50 has a rounded shape in the plan view and is one of the repeating curved segments that make up the scalloped edge shape of the perimeter edge 16. The portion 50 has peak 52. The peak 52 is the point on the perimeter edge 16 that touches the dimple channel DC. The peak 52 may be the midpoint of the portion 50. The channels 18 include a channel centerline CCL that connects the dimple center 20, the central channel point 48, and the peak 52 of the portion 50.
Each channel 18 includes a channel length CL. The channel length CL is measured from the dimple center 20 to the furthest point of the channel measured along the channel centerline CCL (e.g., the dimple center 20 to the peak 52 of the portion 50 of the perimeter edge 16). The channel length CL may also be characterized as a radius of the dimple circle DC. A radius of the channel circle RCC is a length of the first area 42 of the channel 18 and is less than the channel length CL. Each channel also includes a channel width CW. The channel width CW is the largest width of the channel 18, which in the depicted embodiment is measured as a straight-line distance between the terminal ends 24 of the channel edges 22. The channels 18 also include an angle of separation AS. The angle of separation AS is measured as the angle between the channel centerlines CCL. In the embodiment of
The channel 18 has a channel depth DC that is calculated as the distance between the channel edge 22 and the central channel point 48 on the dimple surface 17. The channel depth DC may differ slightly from that shown in
The channel depth DC is a channel parameter, indicating how deep the channel is at a point spaced from the center of the dimple. However, the channel point depth CPD, in general, may be measured at any point within a channel 18 and compared to the channel edge 22. The channel point depth CPD measurement may use a cross-section at the same radial points on the two channel edges 22 that delimit the channel being measured (such as in
The channel depth DC may be compared to the dimple depth DD in another dimple parameter. For example, a ratio between the channel depth DC and the dimple depth DD may further characterize the slope of the dimple surface 17 within the circular sector portions of the channels 18. In an exemplary embodiment, the channel depth DC at the channel circle CC is approximately 1-20% of the dimple depth DD at the dimple center 20.
As mentioned above with respect to
The disclosed embodiments include dimples having radial channels that have a portion that is a circular sector in a plan view. The channels include channel point depths CPD that approach zero at a dimple center and a dimple point depth DPD that approaches a maximum (i.e., the dimple depth DD) at the dimple center. The dimple surface that accommodates these characteristics may take different shapes and configurations and embodiments. The dimples 12 and channels 18 of the above embodiments have a half profile (also referred to herein as dimple profile) that follows a circular arc.
While the depicted examples include matches between the half profile shape of the channel surfaces and the channel edges, it should be understood that other embodiments may combine different profiles. For example, some embodiments may include a channel surface curved in a half profile according to a circular arc, combined with channel edges having a catenary or linear half profile. Other combinations are also possible.
The disclosed embodiments include radial channels and channel edges that alternate in a circumferential direction around the dimple center, making up an entirety of a dimple surface interior to a perimeter edge. As described herein, the radial channels make up an entirety of the dimple surface. As a result, the number of radial channels equals the number of channel edges. Disclosed embodiments may include more or less channels than those depicted. For example, it is contemplated that disclosed embodiments may include between 10 and 50 channels. According to some embodiments, a disclosed dimple may include at least ten channels and ten channel edges. In other embodiments, a disclosed dimple may include at least twenty channels and twenty channel edges. Another embodiment of a disclosed dimple includes fifty channels and fifty channel edges.
In some embodiments, the channels and channel edges may be positioned such that the angle of separation AS is equal for each channel, such as in the dimple 12. This produces an axial symmetric configuration about the dimple center, with axial symmetry in number equal to the number of channels and number of channel edges. For example, the dimple 12 has 26-fold axial symmetry with 26 equal channels 18 and channel edges 22. In other embodiments, a dimple may have channels of different channel widths CW and angles of separation AS. These dimples may or may not have axial symmetry around the dimple center. For example, some dimples may have axial symmetry in number less than he number of channels and channel edges.
Dimples of the present disclosure, which are generally non-spherical in comparison to conventional dimples, may have a plan shape area and dimple volume within a range having a lower limit and an upper limit selected from the values within the region shown in
The plan shape area is based on a planar view of the dimple plan shape, such that the viewing plane is normal to an axis connecting the center of the ball to the point of the calculated surface depth. The dimple volume is the total volume encompassed by the dimple shape and the surface of the golf ball. The preferred dimple volume will be less than the upper limit volume calculated by
V
s=−0.0464x2+0.0135x−2.00×10−5
and greater than the lower limit calculated by
V
s=−0.0300x2+0.0016x−3.00×10−6
where x is the dimple plan shape area and x is between 0.0025 and 0.045 inclusive.
For purposes of the present disclosure, the plan shape area of a non-spherical dimple is based on a planar view of the dimple plan shape, such that the viewing plane is normal to an axis connecting the center of the ball to the point of the calculated surface depth.
An example of a dimple according to disclosed embodiments is further described below. The dimple may have a general appearance of the dimple 12 as shown in
These dimensions are exemplary and may be changed or altered to accommodate different aerodynamic performance of a golf ball. For example, one or more dimensions may be tuned such that the textured/ridged dimples enhance the aerodynamic performance of the golf ball. In another example, the dimensions may be tuned to limit the capabilities of the golf ball and thereby produce a reduced distance golf ball.
Golf balls consistent with the disclosure include at least one disclosed dimple having radial channels. Some golf balls may include a plurality of golf dimples, where all of the dimples have radial channels as disclosed. Other embodiments of golf balls may include a plurality of dimples, with at least one of the dimples being different than the disclosed dimples having radial channels. For example, a golf ball may include a combination of conventional smooth-surface spherical dimples and disclosed dimples having radial channels. The combination of dimples may be arranged in a dimple pattern to produce a desired aerodynamic performance of the golf ball.
Disclosed embodiments may further include methods of manufacturing golf balls having disclosed dimples constructed of radial channels. The disclosed methods may include compression molding, injection molding, or other golf ball manufacturing methods. Golf balls manufactured to include the disclosed dimples on the generally spherical surface may have any golf ball construction known in the art, such as one or more core layers, a casing layer, and a cover layer. The disclosed dimples may be included in the cover layer, which may be covered by one or more paint and/or coating layers.
When numerical lower limits and numerical upper limits are set forth herein, it is contemplated that any combination of these values may be used. All numerical values and ranges set forth herein are approximate.
All patents, publications, test procedures, and other references cited herein, including priority documents, are fully incorporated by reference to the extent such disclosure is not inconsistent with this invention and for all jurisdictions in which such incorporation is permitted.
While the illustrative embodiments of the invention have been described with particularity, it will be understood that various other modifications will be apparent to and can be readily made by those of ordinary skill in the art without departing from the spirit and scope of the invention. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the examples and descriptions set forth herein, but rather that the claims be construed as encompassing all of the features of patentable novelty which reside in the present invention, including all features which would be treated as equivalents thereof by those of ordinary skill in the art to which the invention pertains.
