Title: Golf ball with varying land surfaces
Abstract: A golf ball comprising a substantially spherical outer surface and a plurality of polygonal dimples formed thereon is provided. The dimples are arranged such that the sides of adjacent dimples are substantially parallel to each other, and wherein the outer surface comprises first spacings and second spacings between adjacent dimples. The first spacings and the second spacings have substantially constant width between any two adjacent dimples and the width of the first spacings is different than the width of the second spacings.
Patent Number: 6,884,183 Issued on 04/26/2005 to Sullivan
| Inventors:
|
Sullivan; Michael J. (Barrington, RI)
|
| Assignee:
|
Acushnet Company (Fairhaven, MA)
|
| Appl. No.:
|
779153 |
| Filed:
|
February 13, 2004 |
| Current U.S. Class: |
473/383 |
| Intern'l Class: |
A63B 037//12 |
| Field of Search: |
473/378-385
|
References Cited [Referenced By]
U.S. Patent Documents
| 1681167 | Aug., 1928 | Beldam.
| |
| 4090716 | May., 1978 | Martin et al.
| |
| 4142727 | Mar., 1979 | Shaw et al.
| |
| 4560168 | Dec., 1985 | Aoyama.
| |
| 4729861 | Mar., 1988 | Lynch et al.
| |
| 4830378 | May., 1989 | Aoyama.
| |
| 4869512 | Sep., 1989 | Nomura et al.
| |
| 4960282 | Oct., 1990 | Shaw.
| |
| 4995613 | Feb., 1991 | Walker.
| |
| 5060954 | Oct., 1991 | Gobush.
| |
| 5174578 | Dec., 1992 | Oka et al.
| |
| 5201523 | Apr., 1993 | Miller.
| |
| 5209485 | May., 1993 | Nesbitt et al.
| |
| 5292132 | Mar., 1994 | Kengo.
| |
| 5377989 | Jan., 1995 | Machin.
| |
| 5566943 | Oct., 1996 | Boehm.
| |
| 5575477 | Nov., 1996 | Hwang.
| |
| 5722903 | Mar., 1998 | Moriyama et al.
| |
| 5957786 | Sep., 1999 | Aoyama.
| |
| 6126559 | Oct., 2000 | Sullivan et al.
| |
| 6290615 | Sep., 2001 | Ogg.
| |
| D449358 | Oct., 2001 | Ogg.
| |
| 6358161 | Mar., 2002 | Aoyama.
| |
| 6409615 | Jun., 2002 | McGuire et al.
| |
| 6695720 | Feb., 2004 | Sullivan.
| |
Other References
Golf Ball's Historic Flight, Leonard Shapiro, Washington Post.
|
Primary Examiner: Gorden; Raeann
Parent Case Text
STATEMENT OF RELATED APPLICATION
This application is a continuation of U.S. application Ser. No. 10/157,364 filed
on May 29, 2002, now U.S. Pat. No. 6,695,720, issued on Feb. 24, 2004.
Claims
1. A golf ball comprising:
a substantially spherical outer surface and a plurality of polygonal dimples
formed thereon, said dimples are arranged in dicernable groupings such that the
sides of adjacent dimples are substantially parallel to each other, and wherein
the outer surface comprises first inter-dimple spacings and second inter-sectional
spacings between adjacent dimples, the inter-sectional spacings defining the discernable
groupings, wherein the first spacings and the second spacings have substantially
constant width between any two adjacent dimples and wherein the width of the first
spacings is different than the width of the second spacings
wherein the inter-dimple spacings vary within at least one discernable grouping.
2. The golf ball of claim 1, wherein the polygonal dimples are arranged in a
polyhedron based pattern, and at least some of the inter-sectional spacings form
a single great circle.
3. The golf ball of claim 2, wherein the polyhedron based pattern comprises an
icosahedron pattern, which comprises twenty identifiable triangular sections.
4. The golf ball of claim 1, wherein the inter-dimple spacings are constant within
one discernable grouping.
5. The golf ball of claim 1, wherein the inter-sectional spacings are constant
on the outer surface of the golf ball.
6. The golf ball of claim 1, wherein the inter-sectional spacings vary on the
outer surface of the ball, and at least some of the inter-sectional spacings form
two orthogonal great circles.
7. The golf ball of claim 1, wherein the inter-sectional spacings form a linear
pattern on the outer surface of the ball.
8. The golf ball of claim 7, wherein the linear pattern comprises an equatorial pattern.
9. A golf ball comprising a substantially spherical outer surface and a plurality
of polygonal dimples formed thereon, said dimples are arranged in dicernable groupings
such that the sides of adjacent dimples are substantially parallel to each other,
and wherein the outer surface comprises first inter-dimple spacings and second
inter-sectional spacings between adjacent dimples, the inter-sectional spacings
defining the discernable groupings, wherein the first spacings and the second spacings
have substantially constant width between any two adjacent dimples and wherein
the width of the first spacings is different than the width of the second spacings,
wherein the inter-sectional spacings form a linear pattern on the outer surface
of the ball comprising an equatorial pattern and wherein the linear pattern further
comprises a pattern orthogonal to the equatorial pattern.
10. The golf ball of claim 1, wherein the inter-sectional spacings form a non-linear
pattern on the outer surface of the ball.
11. The golf ball of claim 10, wherein the non-linear pattern comprises a zigzag pattern.
12. A golf ball comprising a substantially spherical outer surface and a plurality
of polygonal dimples formed thereon, said dimples are arranged in dicernable groupings
such that the sides of adjacent dimples are substantially parallel to each other,
and wherein the outer surface comprises first inter-dimple spacings and second
inter-sectional spacings between adjacent dimples, the inter-sectional spacings
defining the discernable groupings, wherein the first spacings and the second spacings
have substantially constant width between any two adjacent dimples and wherein
the width of the first spacings is different than the width of the second spacings,
wherein the inter-dimple spacings have a width of substantially zero.
13. The golf ball of claim 12, wherein the inter-sectional spacings have a width
of about 0.001 inch to about 0.040 inch.
14. The golf ball of claim 1, wherein the inter-sectional spacings have a width
of about 0.002 inch to about 0.030 inch.
Description
FIELD OF THE INVENTION
The present invention relates to golf balls, and more particularly, to a golf
ball having improved dimple patterns.
BACKGROUND OF THE INVENTION
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 the 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 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 actually creates 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, which is evenly distributed around the ball. 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 0.120 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. On the other hand, a smaller number of
large dimples also begin to lose effectiveness. This results from the circumference
of one large dimple being less than that of a group of smaller dimples.
Another attempt to improve dimple coverage is to use polygonal dimples with
the polyhedron dimple surfaces, i.e., dimple surfaces constructed from one or more
planar surfaces, as suggested in a number of patent references including U.S. Pat.
Nos. 6,290,615B1, 5,338,039, 5,174,578, 4,090,716, and 4,830,378, among others.
Theoretically, higher dimple coverage is attainable with these polygonal dimples.
As shown in FIGS. 1 and 2, the land area between the polygonal dimples typically
has uniform width throughout the surface of the ball. As the width of the land
area decreases, the dimple coverage increases.
As recently reported in the press, due to the recent advances in golf ball compositions
and dimple designs, some of the high performance golf balls may eventually exceed
the maximum distance of 280 yards±6%, when impacted by a standard driver at
160 feet per second and at 10° angle as set forth by the United States Golf
Association (USGA). (See "Golf Ball's Historic Flight, New Product Is Hailed for
Distance, Accuracy," by L. Shapiro, The Washington Post at pp. D1, D4, Mar. 22,
2001). As disclosed in U.S. Pat. No. 5,209,485, to reduce the distance that a golf
ball would travel, inefficient dimple patterns and low resilient polymeric compositions
are suggested. Low resilient compositions include a blend of a commonly used diene
rubber, such as high cis polybutadiene, and a low resilient halogenated butyl rubber.
Inefficient dimple patterns include octahedral pattern with dimple free equator
and dimple coverage of less than 50%. As disclosed in the '485 patent, the resulting
ball travels about 50 yards less than comparative balls and has a coefficient of
restitution of about 0.200 less than the coefficient of restitution of comparative
balls. The '485 patent theorizes that about 40% of the reduction in distance is
attributable to the inefficient design, and about 60% is attributable to the low
resilient ball composition. However, the art does not suggest a way to fine-tune
the distance of high performance golf balls to adhere to the USGA limit.
As a result, there remains a need in the art to fine tune the distance that a
golf ball would travel when impacted without affecting the other desired qualities
of the golf ball.
SUMMARY OF THE INVENTION
The present invention is directed to a golf ball, which possesses maximum distance
and control.
The present invention is also directed to a golf ball with a modified dimple pattern.
The present invention is also directed to a golf ball with high visibility features
on its outer surface.
The present invention is directed to a golf ball comprising a substantially spherical
outer surface and a plurality of polygonal dimples formed thereon. The polygonal
dimples are arranged such that the sides of adjacent dimples are substantially
parallel to each other, and the outer surface comprises first spacings and second
spacings between adjacent dimples. The first spacings and the second spacings have
substantially constant width between any two adjacent dimples and the width of
the first spacings is different than the width of the second spacings.
Preferably the polygonal dimples are arranged in a plurality of identifiable
sections and wherein the first spacings comprise inter-dimple spacings between
dimples within one identifiable section and the second spacings comprise inter-sectional
spacings between identifiable sections of dimples.
In accordance to one aspect of the invention, the inter-sectional spacings are
thicker than the inter-dimple spacings.
In accordance to another aspect of the invention, the inter-dimple spacings may
vary throughout the golf ball, while the inter-sectional spacings remain constant.
Conversely, the inter-sectional spacings may vary throughout the ball, while the
inter-sectional spacings remain constant. Alternatively, either the inter-dimple
spacings or the inter-sectional spacings may vary, or both may vary.
In accordance to another aspect of the invention, at least some of the inter-dimple
spacings are thicker than the inter-sectional spacings.
The invention is also directed to a golf ball comprising a substantially spherical
outer surface and a plurality of partially circular dimples formed thereon. Each
of the partially circular dimples comprises a linear side and these dimples are
arranged such that the linear sides of opposite partially circular dimples are
substantially parallel to each other. The linear sides of any two opposite partially
circular dimples form a spacing on the outer surface of the ball.
BRIEF DESCRIPTION OF THE DRAWINGS
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:
FIG. 1 is a plan view of a conventional golf ball with triangular dimples;
FIG. 2 is a plan view of another conventional golf ball with hexagon and pentagon dimples;
FIG. 3A is a plan view of a preferred embodiment of a golf ball in accordance
to the present invention; FIG. 3B is an enlarged view of a section of the golf
ball of FIG. 3A;
FIG. 4 is a partial plan view of another preferred embodiment in accordance
to the present invention;
FIG. 5 is a partial plan view of another preferred embodiment in accordance
to the present invention;
FIG. 6 is a plan view of another preferred embodiment in accordance to the present invention;
FIG. 7 is a partial plan view of another preferred embodiment in accordance
to the present invention;
FIG. 8 is a partial plan view of another preferred embodiment in accordance
to the present invention;
FIG. 9 is a plan view of another preferred embodiment in accordance to the present invention;
FIG. 10 is a partial plan view of another preferred embodiment in accordance
to the present invention;
FIG. 11 is a partial plan view of another preferred embodiment in accordance
to the present invention; and
FIG. 12 is a plan view of another preferred embodiment in accordance to the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
With polygonal dimples, the land or un-dimpled surfaces can approach zero when
the land surfaces separating the polygonal dimples approach thin lines. As discussed
above, with nearly zero land surfaces and highly resilient core/cover materials
the golf ball may exceed currently available distance and overall performance levels.
The distance that a golf ball would travel upon impact is a function of the coefficient
of restitution (CoR) and the aerodynamic characteristics of the ball. The CoR is
defined as the ratio of the relative velocity of two colliding objects after the
collision to the relative velocity of the two colliding objects prior to the collision.
For golf balls, CoR has been approximated as a ratio of the velocity of the golf
ball after impact to the velocity of the golf ball prior to impact. The CoR varies
from 0 to 1.0. A CoR value of 1.0 is equivalent to a perfectly elastic collision,
and a CoR value of 0.0 is equivalent to a perfectly inelastic collision. The CoR
is related to the initial velocity of the ball, which must not exceed 250±5
ft/s, which the maximum limit set forth by the USGA. Hence, the CoR of golf balls
are maximized and controlled, so that the initial velocity of the ball does not
exceed the USGA limit.
The CoR of the golf ball is affected by a number of factors including the composition
the core and the composition of the cover. The core may be single layer core or
multi-layer core. It may also be solid or fluid filled. It may also be wound or
foamed, or it may contain fillers. On the other hand, the cover may also be single
layer cover or multi-layer cover. The cover may be thin or thick. The cover may
have a high hardness or low hardness to control the spin and feel of the ball.
The cover may comprise a thermoplastic or a thermoset material, or both. Compositions
and dimensions of the cover and the core have been fully discussed in the art,
such as U.S. Pat. Nos. 6,419,535, 6,152,834, 5,919,100, 5,885,172, 5,783,293, 5,692,974,
and PCT publication nos. WO 00/29129 and WO 00/23519, among many others. Any of
the above factors can contribute to the CoR of the ball.
In accordance to one aspect of the present invention, a modified dimple pattern
is provided to adjust incrementally the distance that the ball would travel without
affecting the other qualities of the ball. As shown generally in FIGS. 3A and 3B
where like numbers designate like parts, reference number
10 broadly designates
a golf ball
10 having a plurality of dimples
12 separated by outer
un-dimpled or land surfaces. As shown, dimples
12 are triangular. Suitable
dimples for use with this invention include any polygonal dimples, including triangular,
square, rectangular, pentagon, hexagon, heptagon, octagon or any other polygons.
The present invention is not limited to any particular dimple shapes illustrated herein.
As used herein, "inter-dimple spacing" is the distance between any two adjacent
dimples and "inter-sectional spacing" is the distance between any two adjacent
identifiable sections of dimples. Inter-sectional spacing is also the inter-dimple
spacing of adjacent dimples located in adjacent identifiable sections. Preferably,
the spacings between any two adjacent dimples are substantially constant. In other
words, the sides of adjacent dimples are substantially parallel to each other forming
constant spacing between them, such as spacings
20 and
22 shown in
FIGS. 3A and 3B.
In accordance to one aspect of the invention, at least some the inter-dimple
spacings
are different than the inter-sectional spacings. Alternatively, the inter-dimple
spacings may vary throughout ball
10, while the inter-sectional spacings
remain constant. Conversely, the inter-sectional spacings may vary throughout the
ball, while the inter-sectional spacings remain constant. Alternatively, either
the inter-dimple spacings or the inter-sectional spacings may vary, or both may
vary. The inter-dimple spacings, as shown in FIGS. 3A and 3B, are also the width
or the width of the land surface segments interposed between adjacent dimples within
a section of dimples.
The dimple pattern shown in FIG. 3A generally adheres to an icosahedron pattern,
i.e., comprising twenty (20) identifiable triangular sections. One of the triangular
sections is enlarged and shown in FIG.
3B. Within an identifiable triangular
section, the inter-dimple spacings are preferably uniform and are designated as
spacings
20. On the other hand, the spacings between the triangular sections
are relatively larger and are designated as spacings
22. Preferably, spacings
22 are about 1.1 to about 5 times wider than spacings
20. Alternatively,
when inter-dimple spacings
20 have the width of a thin line or effectively
zero width, inter-sectional spacings
22 have a width of about 0.001 to about
0.040 inch, and more preferably about 0.002 inch to about 0.030 inch.
As shown in FIG. 3A, the inter-sectional spacings
22 form a number of
great
circles around the ball, and the inter-sectional spacings
22 have constant
width and are thicker than the inter-dimple spacings, which are also constant on
the ball. As illustrated, the inter-sectional spacings
22 follow the pattern
of an icosahedron. Other suitable patterns include tetrahedron, octahedron, hexahedron
and dodecahedron, among other polyhedrons, or any other discernable grouping of
dimples. As stated above, spacings
20 and
22 may have varying width
on the outer surface of the ball.
The inter-sectional spacings on the golf ball may form a single great circle,
e.g., the equator, as shown in FIG.
4. The hexagonal/pentagonal dimples
are separated by inter-sectional equatorial spacings
24. Dimples
26
are primarily hexagonal dimples, and the inter-dimple spacings
20 are preferably
thin and may become thin lines where neighboring dimples meet as illustrated. Pentagonal
and/or other polygonal dimples may be selectively inserted in the pattern to maximize
dimple coverage. Inter-sectional spacings
24 preferably form non-linear
or more specifically zigzag pattern as shown in FIG.
4. Alternatively, they
may form linear pattern as shown in FIG.
5. FIG. 5 illustrates quadrilateral
dimples
27 having inter-sectional spacings
28 forming two orthogonal
great circles, where preferably one of the great circles is the equator of the
ball. Other polygonal dimples may also be selectively inserted in this pattern
to maximize dimple coverage. Again, the inter-dimple spacings
20 are preferably
thin and may become thin lines where neighboring dimples meet. Also, the sides
of adjacent dimples
26,
27 are substantially parallel to each other
forming constant spacing therebetween.
FIGS. 6,
7 and
8 illustrate other embodiments of the present
invention. In selected sections, the inter-dimple spacings are the same within
one section but are different than the inter-dimple spacings in other sections.
For example, as shown in FIG. 6, triangular dimples are arranged in an icosahedron
pattern having twenty (20) identifiable sections delineated by broken lines. In
one or more of these sections, while the number of dimples is the same as other
sections, these dimples are preferably smaller than other dimples on the ball,
such that the inter-dimple spacings
30 within the selected sections are
significantly larger than the inter-dimple spacings
32 in other sections.
Preferably, the inter-dimple spacings
30 are constant within one section,
but may be different from the inter-dimple spacings in other sections. Preferably,
the sections with larger inter-dimple spacings
30 are evenly distributed
around the surface of the ball to ensure a balanced golf ball. Again, the sides
of adjacent dimples are substantially parallel to each other forming constant spacing therebetween.
Similarly, as shown in FIGS. 7 and 8 dimples in selective dimple groups
may be separated by inter-dimple spacings
34 that have different width than
the inter-dimple spacings
32 on other parts of the ball. Again, these dimple
groups should be evenly distributed around the outer surface of the ball. Importantly,
each dimple group may be contained within a single identifiable section on the
golf ball, or it may straddle across two or more identifiable sections. Again,
the sides of adjacent dimples are substantially parallel to each other forming
constant spacing therebetween.
Alternatively, the inter-dimple spacings in a single identifiable
section may be constant or may vary. As shown in FIG. 9, one of the identifiable
icosahedron sections comprises at least two different inter-dimple spacings
36,
38. A single section may have any number of different inter-dimple spacings
within it. As illustrated, adjacent dimples
40 and
42, while locating
on different icosahedron sections, may have similar inter-dimple spacings
38
with other dimples. Similarly, as shown in FIGS. 10 and 11, adjacent dimples
44,
46 and
48,
50 may have inter-dimple spacings that are different
than other dimples, regardless of their placement in any identifiable sections.
Again, the sides of adjacent dimples are substantially parallel to each other forming
constant spacing therebetween.
Preferably, inter-dimple spacings on a golf ball comprise enlarged spacings
for selected dimples and thin spacings for the remaining dimples. The enlarged
spacings are preferably about 1.1 to about 5 times larger than the thin spacings,
and when the thin inter-dimple spacings approach a line or zero land areas, the
enlarged spacings are preferably about 0.001 to about 0.040 inch, and more preferably
about 0.002 inch to about 0.030 inch.
In accordance to another aspect of the present invention, enlarged inter-dimple
spacings and inter-sectional spacings can be applied to conventional circular dimples,
as shown in FIG.
12. As illustrated, inter-sectional spacings
52
form an equatorial pattern on a golf ball, which has mostly circular dimples. Preferably,
inter-sectional spacing
52 is bordered by partially circular dimples
54.
Each dimple
54 comprises one linear side that is positioned parallel to
a corresponding linear side of an opposite dimple
54 forming constant spacing
therebetween. Partially circular dimple
54 may comprise a linear side and
a circular side, or a linear side and an arcuate side. Additionally, other inter-sectional
spacings similar to those described above, such as other great circles, can also
be used on a ball with circular dimples. Also, enlarged inter-dimple spacings
56
between adjacent dimples can also be formed between partially circular dimples
54 as shown in FIG.
12. Inter-dimple spacings
52 and
56
may have constant width or varying width.
In addition to polygonal and circular dimples, the inter-dimple spacings and
inter-sectional
spacings of the present invention can also be applied to other types of dimples,
such as polygonal spherical dimples as described in co-pending application entitled
"Golf Ball With Spherical Polygonal Dimples" filed on Feb. 15, 2002, Ser. No. 10/077,090.
Other types of suitable dimples include polygonal dimples separated by a tubular
lattice, described in U.S. Pat. No. 6,290,615B1, the isodiametrical dimples, described
in U.S. Pat. No. 5,377,989, or the overlapping dimples, described in U.S. Pat.
No. 4,960,282. The disclosures of these references are incorporated herein by reference.
A tubular lattice comprises a plurality of connecting tubular projections disposed
on the surface of the ball, wherein the cross-sectional profile of each projection
has its apex located farthest from the center of the ball. An isodiametrical dimple
comprises an odd number of sides and arcuate apices, wherein the sides have equal
curvature. An overlapping dimple has a perimeter formed by placing two dimples,
preferably circular dimples, in an overlapping manner.
As discussed above, one advantage of enlarging at least some of the inter-sectional
spacings or inter-dimple spacings is to decrease selectively the dimple coverage,
such that the distance that a high-performance golf ball would travel upon impact
would adhere to the USGA distance limit. The varying inter-dimple spacings and
inter-sectional spacings allow fine tuning of a highly efficient aerodynamic dimple
pattern to adjust the distance that a ball would travel without switching to less
efficient dimple patterns. Fine-tuning an efficient dimple pattern provides more
certainty of achieving the desired result than experimenting with a completely
different dimple pattern, or by changing the composition of the core and/or the
cover to alter the CoR.
Tests have shown that distance generally increases with increasing dimple coverage,
when all other aspects of the ball and tests are equal. Therefore, there is a great
desire to produce dimple designs having as high coverage as possible. Preferably,
the combined land area is less than 15% of the total outer surface area of the
ball. As used herein, total land area is the sum of the areas of inter-dimple spacings
20 and inter-sectional spacings
22. When the inter-dimple spacings
20 approach zero, the total land area is the sum of the inter-sectional
spacings
22.
The inter-dimple spacings and inter-sectional spacings of the present invention
also impart distinctive outer markings on the ball. One advantage of having distinctive
marking, e.g., the equatorial inter-sectional spacings shown in FIG. 4, is that
such markings may assist the golfer's putting game by allowing the golfer to align
the ball to the hole or to the putter. Also, individual designs for high performance
balls may be produced with distinctive markings created by the varying inter-dimple
spacings and inter-sectional spacings such that these balls would be easily distinguished
from other manufacturers balls.
In a preferred embodiment, any of the inventive dimple patterns comprising varying
inter-dimple spacings and/or inter-sectional spacings is utilized on the outer
surface of a golf ball. The golf ball preferably comprises a core and a cover.
The core may have one or more layers, and the cover may also have one or more layers.
The inner cover layer or the outer cover layer may comprise a polyurethane, a polyurea,
a polyurethane ionomer, a partially or fully neutralized ionomer, a metallocene
catalyzed polymer, or blends thereof. Preferably, the outer cover layer has a thickness
of about 0.015 inch to about 0.060 inch, and the inner cover layer has a thickness
of about 0.015 inch to about 0.060 inch. Also, the outer cover layer preferably
has a Shore D hardness of about 10 to about 70, and the inner cover layer has a
Shore D hardness of about 40 to about 90. Also preferably the PGA compression of
the ball is in the range of about 30 to about 100.
Hardness is preferably measured pursuant to ASTM D-2240 in either button
or slab form on the Shore D scale. More specifically, Shore D scale measures the
indentation hardness of a polymer. The higher Shore D value indicates higher hardness
of the polymer.
Compression is measured by applying a spring-loaded force to the golf
ball center, golf ball core or the golf ball to be examined, with a manual instrument
(an "Atti gauge") manufactured by the Atti Engineering Company of Union City, N.J.
This machine, equipped with a Federal Dial Gauge, Model D81-C, employs a calibrated
spring under a known load. The sphere to be tested is forced a distance of 0.2
inch (5 mm) against this spring. If the spring, in turn, compresses 0.2 inch, the
compression is rated at 100; if the spring compresses 0.1 inch, the compression
value is rated as 0. Thus more compressible, softer materials will have lower Atti
gauge values than harder, less compressible materials. Compression measured with
this instrument is also referred to as PGA compression. The approximate relationship
that exists between Atti or PGA compression and Riehle compression can be expressed as:
(Atti or PGA compression)=(160-Riehle Compression).
While various descriptions of the present invention are described above, it
is understood that the various features of the embodiments of the present invention
shown herein can be used singly or in combination thereof. For example, the dimple
depth may be the same for all the dimples. Alternatively, the dimple depth may
vary throughout the golf ball. The dimple depth may also be shallow to raise the
trajectory of the ball's flight, or deep to lower the ball's trajectory. This invention
is also not to be limited to the specifically preferred embodiments depicted therein.
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