Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02307703 2000-08-09
GOLF BALL
BACKGROUND OF THE INVENTION
This invention relates to golf balls and more particularly to a surface
configuration of a golf ball.
DESCRIPTION OF THE PRIOR ART
For many years golf balls have been made with surface indentations or
depressions, called dimples, to improve their aerodynamic properties in
flight.
Many efforts have been made to select the optimum number, size and shape of
dimples as well as their disposition around the outer surface of a generally
spherically shaped golf ball.
Dimples on golf balls are typically circular in elevation cross section, but a
number of other designs are also utilized, including truncated cones, dimples
within dimples, elliptical surfaces, hemispherical (or single radius) dimples,
and
dual radius dimples. For example, U.S. Patent No. 4,979,747 shows dimples
having a frusto-contical elevation view cross section, and U.S. Pat. No.
5,005,838
shows dimples having complex shapes.
Different dimple shapes have different aerodynamic properties, and
therefore, result in different performance characteristics. For example, a
single
radius dimple provides a more gradual entry of the airflow into the dimple,
while a
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dual radius dimple provides a more abrupt entry of the airflow into the
dimple. (A
single radius dimple is one in which the elevation cross sectional shape of
the
dimple can be described by one radius, and dual radius dimple is one in which
the
elevation cross section is described by two radii.)
It has been found that the single radius dimple is the most optimal dimple
shape for a high performance three-piece wound golf ball. By contrast, the
dual
radius dimple is the most optimal shape design for two-piece distance balls
for
providing the desired golf ball flight trajectory. These dimple choices are
based on
the current view that the higher spinning performance balls require a more
gradual entry of the airflow into the dimple to create the desired aerodynamic
effects, whereas the low spinning distance ball requires a more abrupt entry
of the
airflow into the dimple to create the desired aerodynamic effect.
There are a number of hybrid type balls which do not fall squarely within
either the three-piece performance category or the two-piece distance
category. For
example, two-piece performance balls and three-piece distance balls are hybrid
balls which behave like performance balls for certain shots and like distance
balls
for other shots. As used herein the term "hybrid ball" is used to refer to a
two piece
performance ball, a three-piece distance ball, or any other ball which behaves
like a
performance ball for certain shots and like a distance ball for other shots.
It has
been found, for instance that a dimple pattern utilizing dual radius dimples
allows
for a lower more boring trajectory for a distance two-piece ball, whereas a
pattern
utilizing single radius dimples allows for a more consistent flight trajectory
for high
performance three-piece balls.
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A need exists for a dimple pattern (and dimple shape) which takes into
account the unique characteristics of the hybrid ball (i.e. the fact that it
performs
as a distance ball for certain shots, and as a performance ball for other
shots) to
provide optimum performance. The goal is to provide a ball that (i) provides
slightly longer overall distance than a ball utilizing either all single
radius dimples
or all dual radius dimples, and (ii) has a significantly lower trajectory, as
exhibited
by the lower rear trajectory value.
Thus, it is an object of the present invention to provide a golf ball dimple
pattern that optimizes the performance characteristics of the hybrid ball.
It is another object of the present invention to provide a hybrid golf ball
that
provides a slightly longer overall distance and a lower trajectory than the
prior art
hybrid balls.
It is another object of the invention to provide a golf ball having a dimple
pattern that incorporates dimples of different sizes to maximize the
aerodynamic
qualities for each such dimple shape.
It is yet another object of the present invention to provide a golf ball
having
superior distance, trajectory and flight stability.
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SLTMMARY OF THE INVENTION
These and other objectives of the present invention are accomplished
according to the present invention by providing a golf ball having a dimple
pattern
which incorporates dimples of different shapes to maximize the aerodynamic
properties of the ball. The dimple shapes may be selected from any known
dimple
shapes, including but not limited to truncated cones, squares, triangles,
dimples
within dimples, elliptical surfaces, single radius dimples, and dual radius
dimples.
The invention allows for the combination of any of the possible dimple shapes
into
a single dimple pattern to allow a more optimized golf ball flight trajectory.
The golf ball of the preferred embodiment is a hybrid ball in which the
dimple pattern on the surface of the ball includes both single radius and dual
radius dimples in order to achieve the most optimal flight performance. This
hybrid ball is allowed to best utilize the aspects of single radius dimples
for shots
where it behaves more like a performance three-piece ball, and the aspects of
dual
radius dimples for shots where it behaves like a distance ball, while
maintaining
good flight performance and control with a combination of both. The ball
provides
slightly longer overall distance, and a significantly lower trajectory than
the prior
art hybrid balls. This is a much-desired property for this type of ball.
The dimples are arranged by dividing the outer spherical surface of a golf
ball into a plurality of polygonal configurations, including pentagons,
squares and
triangles for locating a plurality of dimples on the outer surface of the golf
ball.
The polygonal configurations of this invention are preferably a combination of
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regular pentagons, squares and triangles to cover the outer surface. This
first
plurality of polygonal configurations is generally referred to herein as a
"rhombicosadodecahedron". The rhombicosadodecahedron is further characterized
by a uniform pattern of pentagons formed over the outer surface each bounded
by
triangles and squares.
The preferred embodiment utilizes a pattern of 402 dimples arranged in the
construction of the rhombicosadodecahedron. A pair of first polygonal
configurations, each located on opposite sides of the outer surface, include
one of
the two poles symmetrically arranged within its boundaries. The outer surface
has
a plurality of dimples of different sizes. In one embodiment, the dimples are
of
first, second and third sizes and are generally located to have a first
pattern
associated with the pentagons, a second pattern associated with the squares,
and a
third pattern associated with the triangles.
In another embodiment of the invention, the outer surface of the golf ball
includes a plurality of parting lines along great circle paths of the ball for
further
dividing the first plurality of polygonal configurations into a second
plurality of
polygonal configurations, each of which are smaller than the polygonal
configurations of the first polygonal configurations. The dimples are arranged
over
the outer surface by being associated with both the first and the second
plurality of
polygonal configurations.
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Description of the Drawings
The invention will be more readily understood from a reading of the
following specification and by reference to the accompanying drawings forming
a
part thereof, wherein an example of the invention is shown and wherein:
Figure 1 is an elevation view of the outer surface of a golf ball being
divided
into a plurality of polygonal configurations according to the invention;
Figure 2 is an elevation view of the golf ball of this invention showing the
relative locations of pentagons, squares and triangles formed on the outer
surface
with a pole at the center of a pentagon;
Figure 3 is an elevation view of the golf ball of this invention showing the
relative locations of pentagons, squares and triangles formed on the outer
surface
with a pole at the center of a square;
Figure 4 is an equatorial view of the ball of preferred embodiment of the
present invention;
Figure 5 is a polar view of the ball shown in Figure 4;
Figure 6 is an equatorial view of the ball shown in Figure 4, and includes
polygons projected thereon;
Figure 7 is a polar view of the ball shown in Fig. 5 and include polygons
projected thereon;
Figure 8 is an elevation view of the golf ball showing circular dimples of
three sizes being located on the outer surface of the golf ball to correspond
with the
polygonal configurations of Figure 2;
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Figure 9 is an elevation view of the golf ball of Figure 4 rotated to show an
equatorial great circle path defining a mold line;
Figure 10 is an elevation view of the outer surface of the golf ball being
further divided by a plurality of parting lines of the polygonal
configurations to
form another embodiment of the invention;
Figure 11 is an elevation view of the golf ball showing dimples located on the
outer surface of the golf ball to correspond with the polygonal configurations
and
parting lines of Figure 10;
Figure 12 is an elevation view of the golf ball showing dimples associated
with five parting lines on the outer surface of the golf ball to correspond
with the
polygonal configurations and parting lines of Figure 2;
Figure 13 is an elevation view of the golf ball of Figure 12 rotated to show
an
equatorial great circle path defining a mold line;
Figure 14 is an elevation view of the golf ball showing non-circulax dimples,
being triangles and squares, located on the outer surface of the golf ball to
correspond with the polygonal configurations of Figure 2;
Figure 15 is an elevation view of the golf ball of Figure 14 rotated to show
an
equatorial great circle path defining a mold line;
Figure 16 is a cross sectional view cut through one of the dimples on the
outer surface of the ball;
Figure 17 is a cross sectional view of a single radius dimple; and
Figure 18 is a cross sectional view of a dual radius dimple.
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DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now in more detail to the drawings, the invention will now be
described in more detail. The golf ball 5 may have a unit construction in a
single
piece, molded from a suitable rubber or plastic composition; it may be of a
two-piece
ball construction having a separately applied cover applied around a core; it
may be
of a three piece wound ball with a liquid or solid center; or it may be a
multipiece
solid golf ball. The cover is molded from a material suitable for golf balls.
It may
be molded as two separate hemispherical half shells that are then compression
molded or injection molded around the core.
The dimple configuration will normally be applied to the ball during the
molding of the cover around the core by using appropriately shaped negative
molds
containing the dimple pattern in reverse. The molded golf ball having the
desired
dimple configuration may be then painted. Alternately, painting may be
unnecessary for one-piece golf balls using a cover having a suitable
compounding of
the composition used.
Accordingly, the scope of this invention provides a golf ball mold whose
molding surface contains a uniform pattern to give the golf ball a dimple
configuration superior to those of the prior art. The invention is preferably
described in terms of the golf ball that results from the mold, but could be
described
within the scope of this invention in terms of the mold structure that
produces a
golf ball.
To assist in locating the dimples on the golf ball, the golf ball 5 of this
invention has its outer spherical surface partitioned by the projection of a
plurality
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of polygonal configurations onto the outer surface. That is, the formation or
division that results from a particular arrangement of different polygons on
the
outer surface of a golf ball is referred to herein as a "plurality of
polygonal
configurations." A view of one side of a golf ball 5 showing a preferred
division of
the golf ball's outer surface 7 is illustrated in Fig. 1.
In the preferred embodiment, a polygonal configuration known as a
rhombicosadodecahedron is projected onto the surface of a sphere. A
rhombicosadodecahedron is a type of polyhedron which contains thirty (30)
squares, twenty (20) polyhedra of one type, and twelve (12) polyhedra of
another
type. The term "rhombicosadodecahedron" is derived from "dodecahedron,"
meaning a twelve (12) sided polyhedron; "icosahedron," meaning a twenty (20)
sided polyhedron, and "rhombus" meaning a four sided polyhedron.
The rhombicosadodecahedron of the preferred embodiment is comprised of
thirty (30) squares 12, twelve (12) pentagons 10, and twenty (20) triangles
14. It
has a uniform pattern of pentagons with each pentagon bounded by triangles and
squares. The uniform pattern is achieved when each regular pentagon 10 has
only
regular squares 12 adjacent to its five boundary lines, and when a regular
triangle
14 extends from each of the five vertices of the pentagon. Five (5) squares 12
and
five (5) triangles 14 form a set of polygons around each pentagon. Two
boundary
lines of each square are common with two pentagon boundary lines, and each
triangle has its vertices common with three pentagon vertices.
The outer surface of the ball is further defined by a pair of poles and an
equatorial great circle path around the surface. A great circle path is
defined by
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the intersection between the spherical surface and a plane, which passes
through
the center of the sphere. An infinite number of great circle paths may be
drawn on
any sphere. The equatorial great circle path in the preferred embodiment
corresponds to a mold parting line that separates the golf ball into two
hemispheres. The mold parting line is located from the poles in substantially
the
same manner as the equator of the Earth is located from the North Pole and the
South Pole.
Referring to Fig. 2, the poles 70 are located at the center of a pentagon 10
on
the top and bottom sides of the ball, as illustrated in this view of one such
side.
The mold parting line 30 is at the outer edge of the circle in this planar
view of the
golf ball. In the embodiment shown in Fig. 3, the poles 72 are both located at
the
center of the square on the top and bottom of the golf ball, as illustrated in
this
view of one such side. (The top and bottom views are identical.) The mold
parting
line 40 is at the outer edge of the circle in this planar view of the golf
ball.
Dimples are placed on the outer surface of the golf ball based on segments of
the plurality of polygonal configurations described above. In the preferred
embodiment, three (3) dimples are associated with each triangle, five (5)
dimples
are associated with each square, and sixteen (16) dimples are associated with
each
pentagon. The term "associated" as used herein in relation to the dimples and
the
polyhedra means that the polyhedra are used as a guide for placing the
dimples.
The dimple configuration of the preferred embodiment is shown in Figs. 4-7.
It is based on the projection of the rhombicosadodecahedron shown in Fig. 2.
The
ball has a total of 402 dimples. The plurality of dimples on the surface of
the ball
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are selected from three sets of dimples, with each set having different sized
dimples. Dimples 200 are in the first set, dimples 202 are in the second set,
and
dimples 204 are in the third set. Dimples are selected from all three sets to
form a
first pattern associated with the pentagon 10. All sides 206 of each pentagon
are
intersected by two dimples 200 from the first set of dimples and one dimple
202
from the second set of dimples. All pentagons 10 have the same general first
pattern arrangement of dimples.
Dimples 200, 202 and 204 (from all three sets of dimples) are also used to
form a second pattern associated with the squares 12. All sides 208 of each
square
12 are intersected by dimples 202 from the second set of dimples, and all
squares
have the same general second pattern arrangement of dimples.
Dimples 202 from the second set of dimples form a third pattern associated
with the triangles 14. All sides 210 of each triangle are intersected by a
dimple 202
from this second set of dimples. All triangles have this same general third
pattern
arrangement of dimples. The mold parting line 30 is the only dimple free great
circle path on this ball.
The ball of the preferred embodiment utilizes two different types of dimples
having two different cross-sections, single radius dimples 200 and 204 and
dual
radius dimples 202. In the single radius dimple (Fig. 17), a single radius
(referred
to as a major radius, or Radius 1) describes the shape of the bottom of the
dimple.
In other words, the major radius governs the shape of the dimple toward the
bottom of the dimple. In a dual radius dimple (Fig. 18), on the other hand,
two
radii are used to describe the shape of the dimple. The major radius describes
the
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bottom of the dimple, and a minor radius (R,adius 2) describes the shape of
the
dimple about its circumference.
Dimple size is measured by a diameter and depth generally according to the
teachings of U.S. Patent No. 4,936,587 (the '587 patent), which is included
herein
by reference thereto. An exception to the teaching of the '587 patent is the
measurement of the depth, which is discussed below. A cross-sectional view
through a typical single radius dimple 6 is illustrated in Fig. 16. The
diameter Dd
used herein is defined as the distance from edge E to edge F of the dimple.
Edges
are constructed in this cross-sectional view of the dimple by having a
periphery 50
and a continuation thereof 51 of the dimple G. The periphery and its
continuation
are substantially a smooth surface of a sphere. An arc 52 is inset about 0.003
inches below curve 50-51-50 and intersects the dimple at point E' and F'.
Tangents
53 and 53' are tangent to the dimple 6 at points E' and F' respectively and
intersect
periphery continuation 51 at edges E and F respectively. The exception to the
teaching of '587 noted above is that the depth d is defined herein to be the
distance
from the chord 55 between edges E an F of the dimple 6 to the deepest part of
the
dimple cross sectional surface 6 (a), rather than a continuation of the
periphery 51
of an outer surface 50 of the golf ball.
The dimple dimensions for the preferred embodiment are set forth below:
Dimple (number) Diameters Type Radius 1 in Radius 2 in
200 (60) .156 Single .4148 NA
202 (150) .145 Dual .7874 .1181
204 (192) .140 Single .3535 NA
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It is understood that the following dimple size ranges are within the scope of
this
invention: dimples 200 from the first set may have a diameter in the range of
0.150
inches to 0.160 inches; dimples 202 from the second set may have a diameter in
the
range of 0.140 inches to 0.150 inches; dimples 204 from the third set may have
a
diameter in the range of 0.135 inches to 0.145 inches; all dimples, 200, 202
and 204
may have a depth in the range of 0.0056 inches to 0.0078 inches; the major
radius
may be in the range of 0.34 inches to 0.80 inches; and the minor radius (for
dimple
202) may be in the range of 0.10 inches to 0.12 inches.
The following test data illustrates the improved performance of the dimple
pattern of the present invention. Each of the balls identified below is a
hybrid ball.
BALL #DIMPLES PATTERN TYPE CARRY(YDS~ TOTAL (YDS~ REARTRAJ.
BB344 402 all single rad. 247.8 268.0 8.4
BB351 402 all dual rad. 246.3 268.2 8.2
BB370 402 combination 246.6 270.0 8.2
Control 392 all single rad. 245.6 267.5 8.3
As shown above, the ball of the present invention, which utilizes both single
radius and dual radius dimples, provides slightly longer overall distance than
a
ball utilizing either all single radius dimples or all dual radius dimples,
and it has
a significantly lower trajectory, as exhibited by the lower rear trajectory
value.
This is a much-desired property for the hybrid ball.
Fig. 8 shows another embodiment of the present invention. The dimples are
arranged on the surface of the ball based on the projection of the
rhombicosadodecahedron as shown in Fig. 2. The poles are located at the center
of
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the pentagons on the top and bottom of the balls (Fig. 8). The mold parting
(30)
line is the only great circle path on the ball that is not intersected by a
dimple. A
rotated view of the ball shown in Fig. 8 is shown in Fig. 9. A mold parting
surface
80 adjacent the mold parting line 30 is formed by defining a great circle path
void
of dimples. The mold parting line 30 runs through certain of the squares 12a
and
triangles 14a projected onto the surface. The dimples adjacent the mold line
30
help to form boundaries of the mold parting surface.
The plurality of dimples on the surface of the ball shown in Fig. 8 are
selected from three sets of dimple of three different sizes. Dimples 60 are
from a
first set of dimples, dimples 61 are from a second set, and dimples are 62
from a
third set. Dimples 60 and 62 form a first pattern associated with the
pentagons 10.
All sides 11 of each pentagon 10 are intersected by dimples 61 from the second
set
and all pentagons 10 have the same general first pattern of dimples. All sides
13 of
each square 12 are intersected by third dimples 62, and all squares 12 have
the
same general second pattern arrangement of dimples. The first dimples 60 form
a
third pattern associated with the triangles 14. All sides 15 of each triangle
14 are
intersected by first dimples 60 and all triangles have the same general third
pattern arrangement of dimples. In this embodiment, the dimples 60 are larger
than the dimples 61, which in turn, are larger than the dimples 62. The sizes
of
the dimples 60, 61, and 62 correspond to the sizes of the dimples 200, 202,
and 204,
respectively, as described above.
A secondary partitioning of the outer surface of the golf ball is superimposed
on the rhombicosadodecahedron previously described, as illustrated in Fig. 10.
For
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this embodiment the two poles 72 are located at the center of squares and the
mold
line 40 is formed as illustrated in Fig. 3. This second partitioning is
realized by
forming parting lines or bisectors 20 along great circle paths that
essentially divide
each pentagon 10 into ten (10) smaller triangles 36 of equal size. These
parting
lines 20 also divide each square into four (4) smaller squares 32 and each
triangle
14 into six smaller triangles 34. This further division of the outer surface
of the
golf ball allows the location of dimples over a greatly expanded number of
polygonal configurations. It further allows a mold line 40 to be selected to
correspond with any one of the parting lines 20 to create a true mold line and
fourteen false mold lines.
A possible dimple pattern for the polygonal configuration of Fig. 10 is
illustrated in Fig. 11. For this embodiment the dimples are located within all
fifteen of the parting lines 70. That is, none of the parting lines are
intersected by
any dimple. Three different dimple sizes are shown in Fig. 11; with the
largest
sized dimples located within the squares. This arrangement of dimples is
illustrative of having no dimples intersect parting lines. The number of
dimples in
each of the smaller triangles and squares can be substantially different from
the
number shown, within the scope of this invention. Dimples are, once again,
formed
and measured as illustrated in Fig. 16.
Another embodiment of the polygonal configurations including certain
parting lines is illustrated in Fig. 12. This embodiment uses only five
parting lines
70a and 70b of the fifteen parting lines 20 illustrated in Fig. 10. These
certain
parting lines are not intersected by any dimples. The mold parting line
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corresponds to one great circle path 70b, as illustrated in the rotated view
of the
golf ball of Fig. 13. The dimple layout in parts of the outer surface adjacent
the five
great circle paths may be substantially different than the dimple layout in
parts of
the outer surface not adjacent the five great circle paths. One example of a
dimple
layout having dimples approximately equal in size is illustrated in Figs. 12
and 13.
The previous embodiments illustrate dimples that are formed as generally
circular in a plan view of each dimple. Other embodiments of the present
invention
include dimples that are non-circular in form, as illustrated in Figs. 14 and
15.
These illustrations show the use of the polygonal configurations of Fig. 2;
where the
pentagons 10 have twenty (20) triangular shaped dimples, the squares 12 have
four square shaped dimples and the triangles 14 have four triangular shaped
dimples. The triangular shaped dimples have a height in the range of 0.037
inches
to 0.149 inches, and a base in the range of 0.037 inches to 0.149 inches. The
squared shaped dimples have a height in the range of 0.037 inches to 0.224
inches
and a width in the range of 0.037 inches to 0.224 inches.
Dimples at the equatorial great circle path defining a mold parting line 30
are divided into two parts, as illustrated in Fig. 9. Each one of the parts
appears in
a single one of the polygonal configurations. For the embodiment illustrated,
the
mold line divides certain square shaped dimples 100 within the squares 12 into
two
parts 102 and 104. A mold parting surface 30a is formed by partially
eliminating
the depression of the certain square shaped dimples adjacent to the mold
parting
line without changing the general shape or location of these dimples. For
example,
the two parts 102 and 104 of a parted square dimple are essentially the same
size
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and shape as the square dimple 100. The mold parting surface becomes bounded
by parted dimples. The irregular shaped dimples are measured on the basis of
spherical shaped dimples having equivalent surface areas and cross sectional
areas
as set forth above.
The dimples may be placed on the outer surface of the golf ball to intersect
all of the parting lines constructed on the outer surface, none of the parting
lines,
or only some of the parting lines on the outer surface. When great circle
paths are
not intersected by dimples they become true parting lines for defining the
dimple
pattern.
Fig. 8 shows all of the parting lines intersected by dimples; Fig. 11 shows
none of the parting lines intersected by dimples; and Fig. 12 shows ten of the
parting lines intersected by dimples. While a preferred embodiment of the
invention has been described using specific terms, such description is for
illustrative purposes only, and it is to be understood that changes and
variations
may be made without departing from the spirit or scope of the following
claims.
For example, it is understood that the invention is not limited to a dimple
pattern
defined by the rhombicosadodecahedron.
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