U.S. patent application number 12/838846 was filed with the patent office on 2012-01-19 for golf ball having multiple identical staggered parting lines.
Invention is credited to Steven Aoyama, Michael R. Madson, Nicholas M. Nardacci.
Application Number | 20120015761 12/838846 |
Document ID | / |
Family ID | 45467399 |
Filed Date | 2012-01-19 |
United States Patent
Application |
20120015761 |
Kind Code |
A1 |
Madson; Michael R. ; et
al. |
January 19, 2012 |
GOLF BALL HAVING MULTIPLE IDENTICAL STAGGERED PARTING LINES
Abstract
A golf ball having multiple sets of identical hemispheres
created by multiple non-planar parting lines symmetrically
arranged. The hemispheres are identical relating to dimple volume,
distribution and location. The highest amplitude of a parting line,
when measured from an equator, is less than 11% of the largest
dimple diameter.
Inventors: |
Madson; Michael R.;
(Pawtucket, RI) ; Nardacci; Nicholas M.; (Bristol,
RI) ; Aoyama; Steven; (Marion, MA) |
Family ID: |
45467399 |
Appl. No.: |
12/838846 |
Filed: |
July 19, 2010 |
Current U.S.
Class: |
473/379 ;
473/378; 473/380; 473/382; 473/383 |
Current CPC
Class: |
A63B 37/0006
20130101 |
Class at
Publication: |
473/379 ;
473/378; 473/382; 473/383; 473/380 |
International
Class: |
A63B 37/14 20060101
A63B037/14; A63B 37/12 20060101 A63B037/12; A63B 37/00 20060101
A63B037/00 |
Claims
1. A golf ball comprising multiple symmetrical identical non-planar
parting lines creating multiple hemispheres that are nominally
identical in terms of dimple shape, size, volume, distribution, and
location.
2. The golf ball according to claim 1, wherein the number of the
parting lines is three and the number of the hemispheres is
six.
3. The golf ball according to claim 2, wherein the dimple pattern
is octahedral.
4. The golf ball according to claim 2, wherein no polar region
dimples have been modified in shape or cross-sectional profile.
5. The golf ball according to claim 2, wherein no polar region
dimples are elliptical in shape with a nonzero eccentricity.
6. The golf ball according to claim 1, wherein the number of the
parting lines is four and the number of the hemispheres is
eight.
7. The golf ball according to claim 6, wherein the dimple pattern
is cuboctahedral.
8. The golf ball according to claim 6, wherein no polar region
dimples have been modified in shape or cross-sectional profile.
9. The golf ball according to claim 6, wherein no polar region
dimples are elliptical in shape with a nonzero eccentricity.
10. The golf ball according to claim 1, wherein the number of the
parting lines is six and the number of the hemispheres is
twelve.
11. The golf ball according to claim 10, wherein the dimple pattern
is icosidodecahedral.
12. The golf ball according to claim 10, wherein no polar region
dimples have been modified in shape or cross-sectional profile.
13. The golf ball according to claim 10, wherein no polar region
dimples are elliptical in shape with a nonzero eccentricity.
14. The golf ball according to claim 1, wherein the number of the
parting lines is ten and the number of the hemispheres is
twenty.
15. The golf ball according to claim 14, wherein no polar region
dimples have been modified in shape or cross-sectional profile.
16. The golf ball according to claim 14, wherein no polar region
dimples are elliptical in shape with a nonzero eccentricity.
17. The golf ball according to claim 1, wherein the number of the
parting lines is at least three and the number of the hemispheres
is twice the number of the parting lines.
18. The golf ball according to claim 17, wherein no polar region
dimples have been modified in shape or cross-sectional profile.
19. The golf ball according to claim 17, wherein no polar region
dimples are elliptical in shape with a nonzero eccentricity.
20. The golf ball according to claim 1, wherein the maximum
amplitude of the real parting line when measured from the equator
is less than 53% of the largest adjacent dimple diameter or span
D.sub.MAX.
21. The golf ball according to claim 1, wherein the maximum
amplitude of a real parting line when measured from the equator is
less than 26% of the largest adjacent dimple diameter or span
D.sub.MAX.
22. The golf ball according to claim 1, wherein the maximum
amplitude of a real parting line when measured from the equator is
less than 11% of the largest adjacent dimple diameter or span
D.sub.MAX.
Description
FIELD OF THE INVENTION
[0001] The invention relates in general to a golf ball, and more
particularly, to an improved golf ball having multiple sets of
identical hemispheres created by non-planar parting lines
symmetrically arranged.
BACKGROUND OF THE INVENTION
[0002] The usual golf ball manufacturing techniques include several
different steps, depending on the type of ball, such as one, two,
three or even more than three piece balls. In general, a solid or
composite elastomeric core of one or more layers is made, and an
outer dimpled cover is formed around the core.
[0003] There are several methods well known in the art for molding
a cover over a core, including compression molding, injection
molding, and casting. Irrespective of the method, the molding
operation is accomplished by using a pair of generally
hemispherical mold cavities, each of which has an array of
protrusions machined or otherwise provided in its cavity, said
protrusions forming the dimple pattern on the periphery of the golf
ball during the cover molding operation.
[0004] When dimple protrusions are formed on the mold cavity
surface, they are typically positioned between the equator and the
pole of the resulting mold cavity. The parting line is typically
machined after the dimple forming process. For ease of
manufacturing, the parting line of the cavity is usually machined
as a flat surface generally coinciding with the equator plane of
the mold cavity. During the molding process, this provides positive
shut off preventing flowing cover material from leaking out of the
mold. This dimple positioning and flat parting line results in a
great circle path on the ball that is essentially devoid of
dimples. This is commonly referred to as the equator, parting line,
or seam of the ball. Over the years dimple patterns have been
developed to compensate for aesthetic and/or flight performance
issues arising from the presence of the seam.
[0005] It is well known that the dimple pattern of a golf ball is a
critical factor insofar as the flight characteristics of the ball
are concerned. The dimples influence the aerodynamic lift and drag
forces exerted on the golf ball which in turn strongly influence
its overall performance and flight stability. When a golf ball is
struck properly, it will spin about an axis and the interaction
among the spin, the dimples and the oncoming air stream will
produce the desired lift, drag, and flight characteristics.
[0006] In order for a golf ball to achieve optimum flight
consistency, it is beneficial for its dimples to be arranged with
multiple axes of symmetry. Otherwise, the ball might fly
differently depending upon its orientation prior to being struck.
Golf balls that include only a single dimple free equatorial
parting line inherently are limited to only one symmetry axis. In
order to achieve good flight consistency, it is often necessary to
compensate for this limitation by adjusting the positions and/or
dimensions and/or shapes of certain dimples. Alternatively,
additional symmetry axes can be created by incorporating additional
"false" parting lines. However, each false parting line is dimple
free like the real one, so this practice tends to increase the
amount of undimpled surface on the ball, resulting in reduced ball
flight distance.
[0007] This problem can be solved by allowing dimples to intersect
the equator, and using a non-planar (stepped, zig-zag, wavy,
staggered, or otherwise corrugated) parting line that encircles the
ball in the equator vicinity while skirting the dimples. Since this
type of parting line does not necessarily increase the amount of
undimpled surface, adding multiple false duplicates also need not
increase the amount of undimpled surface. Some U.S. patents that
seek to place dimples intersecting the equator of the ball include
U.S. Pat. Nos. 6,200,232, 6,123,534 and U.S. Pat. No. 5,688,193 to
Kasashima et al., U.S. Pat. No. 5,840,351 to Inoue et al., and U.S.
Pat. No. 4,653,758 to Solheim. These patents introduced "stepped"
and/or "zig zag" parting lines. While this could potentially
improve the consistency and symmetry of flight performance, it does
not sufficiently improve dimple coverage, since the parting lines
include straight segments that do not permit tight dimple packing
on opposite sides. A stepped path often results in a greater loss
of dimple coverage than a straight path because it discourages
interdigitation for a larger number of dimples
[0008] Efforts to improve dimple symmetry have explored the use of
multiple parting lines and the resulting dimple patterns produced.
U.S. Pat. Nos. 4,560,168 and 5,415,410 issued to Aoyama disclose
the use of six and three great circle parting lines respectively.
This produces multiple axes of symmetry, but there is a likely
reduction of dimple coverage resulting from the multiple planar
parting lines. U.S. Pat. No. 7,179,178 to Veilleux et al. teaches
the use of three non-planar parting lines defining hexispheres.
However, there is no provision for multiple axes of symmetry, nor
are the six hemispheres produced by the three parting lines likely
to be identical.
[0009] Therefore, a need exists for an improved golf ball combining
a high degree of dimple coverage, multiple axes of symmetry, and
multiple hemispheres that are substantially identical to each
other.
SUMMARY
[0010] The present invention relates to a golf ball produced by a
mold that forms multiple symmetrically arranged non-planar parting
lines to create multiple identical hemispheres. Whereas only one
parting line is the real one, all of them create identical
hemispheres that contain dimple patterns that are essentially
identical relating to dimple shape, size, volume, distribution and
location.
[0011] Each embodiment of the invention provides for a golf ball
wherein the sum of all the volumes of the dimples lying
predominantly above the equator is equal to the sum of all the
volumes of the dimples lying predominantly below the equator.
[0012] An embodiment of the invention provides for at least three
non-planar parting lines, one being a real parting line, and the
remaining ones being false. This embodiment creates at least six
substantially identical hemispheres.
[0013] An embodiment of the invention provides that the distance
between the amplitude of a non-planar parting line and the equator
of the ball is less than 53% of the largest dimple diameter,
preferably less than 26% and more preferably less than 11%.
[0014] In the present invention, the number of identical non-planar
parting lines is determined by the polyhedral geometry underlying
the dimple pattern. For example, for an octahedron based dimple
pattern the total number of real and false identical parting lines
is three and the number of identical hemispheres is therefore six.
For an icosidodecahedron dimple pattern, the total number of real
and false identical parting lines is six and thus the number of
identical hemispheres is twelve. For a cuboctahedron dimple pattern
the total number of real and false parting lines is four and the
number of identical hemispheres is eight. Other patterns have as
many as ten total real and false identical parting lines and twenty
identical hemispheres.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is an enlarged equatorial view of a golf ball of the
present invention showing a non-planar parting line in relationship
to the equator.
[0016] FIG. 2 is an enlarged view of a golf ball of the present
invention having an octahedron dimple layout including a real
parting line and two false parting lines.
[0017] FIG. 3 is a view showing the two hemispheres of the dimple
layout of FIG. 2 that are delineated by the real parting line.
[0018] FIG. 4 is a view showing the two hemispheres of the dimple
layout of FIG. 2 that are delineated by the first false parting
line.
[0019] FIG. 5 is a view showing the two hemispheres of the dimple
layout of FIG. 2 that are delineated by the second false parting
line.
DETAILED DESCRIPTION OF THE INVENTION
[0020] Most dimple patterns have a real parting line that
delineates two substantially identical hemispheres. However, dimple
patterns with additional matching false parting lines can have more
than two such hemispheres and higher orders of symmetry. Some
benefits of this include: more even dimple distribution; potential
for higher packing efficiency; and improved methods to mask the
real molded parting line of the ball. Further, it is anticipated
that dimple patterns generated in this manner have improved
stability and symmetry of flight as a result of the higher degree
of dimple pattern symmetry. This concept has been noted before;
however it has only been seen in prior art golf balls having flat
parting lines and patterns that don't have the additional identical
hemispheres. The present invention has provided a golf ball, not
only with multiple identical non-planar parting lines and symmetry
order greater than two, but wherein the dimples are arranged in
such a way as to create more than two identical hemispheres and
parting lines that maintain a functional relationship to the
underlying polyhedral geometry.
[0021] Some dimple patterns contain false parting lines in an
attempt to hide the manufacturing mold parting line on the golf
ball, but these parting lines are merely similar in appearance. In
the present invention, the false parting lines that are created are
nominally exact replicas of the actual parting line. It is
understood that the false parting lines are not physically present
on the golf ball; rather they represent imaginary paths that are
identical to the real parting line in shape and geometric
relationship to neighboring dimples. The number and distribution of
these parting lines is a by-product of the underlying geometry and
method employed to develop these dimple patterns. The pattern is
designed as follows:
[0022] (1) FIG. 1 shows dimples on a golf ball 10 that are packed
in a manner to allow for a non-planar parting line 14, such that
the manufacturing mold parting line lies on both sides of the ball
equator.
[0023] (2) The parting line is such that the sum of the volumes of
the dimples lying predominantly above the equator (V.sub.DA) is
equal to the sum of the volumes of the dimples lying predominantly
below the equator (V.sub.DB):
.SIGMA.V.sub.DA=.SIGMA.V.sub.DB Equation 1
[0024] A dimple is considered to lie predominantly above the
equator 12 if its center point lies above the equator, and
predominantly below the equator if its center point lies below the
equator. For non-circular dimples, the center point is defined to
be the centroid of the dimple.
[0025] (3) In order to maintain manufacturability as well as
pattern symmetry, the maximum amplitude of the parting line
(A.sub.p) from equator 12 is at most 53% of the nominal design
diameter of the largest dimple that is adjacent to the parting line
(D.sub.MAX):
A.sub.P.ltoreq.0.53(D.sub.MAX) Equation 2
Preferably,
A.sub.P.ltoreq.0.26(D.sub.MAX) Equation 3
More preferably,
A.sub.P.ltoreq.0.11(D.sub.MAX) Equation 4
[0026] For non-circular dimples, D.sub.MAX is the vertical span of
the dimple (measured perpendicular to the equator) rather than the
diameter.
[0027] (4) The staggered parting line is nominally exactly
replicated so that it appears several times on the ball, and the
total number of identical parting lines (N.sub.PL) follows Equation
5. This value depends upon the polyhedron used to define the
pattern. An example using an octahedron layout is shown in FIG.
2:
N.sub.PL.gtoreq.3 Equation 5
[0028] (5) The dimple pattern is further defined such that any of
the real or false parting lines on the ball splits the pattern into
two nominally identical dimpled hemispheres (H.sub.n &
H.sub.n+1), as seen in FIGS. 3-5. The hemispheres are essentially
indistinguishable in terms of dimple shape, size, volume,
distribution and location. Furthermore, the hemispheres created by
any given parting line are the same as the hemispheres created by
any other parting line. FIG. 4 depicts the hemispheres H.sub.1 and
H.sub.2 split on the real parting line 14, while FIG. 4 shows the
hemispheres H.sub.3 and H.sub.4 split on the first false parting
line 16, and FIG. 5 shows the hemispheres H.sub.6 and H.sub.6 split
at the second false parting line 18.
[0029] (6) As stated above, the parting lines 14, 16, and 18 split
the ball into six nominally identical hemispheres. This high degree
of symmetry is anticipated to yield enhanced flight stability and
aerodynamic consistency. It is understood that in certain
situations, dimples that are nominally the same in shape, size,
volume, distribution or location may not be precisely identical.
This can result from manufacturing variations, especially related
to paint coats or other finishing operations, from the presence of
various manufacturing code markings in the dimples, or from
variations due to molding techniques. For example, golf balls with
injection molded covers typically include certain dimples in the
polar regions (usually within 30.degree. latitude from the pole)
that have been slightly modified geometrically in order to
accommodate retractable pins and vents. Specifically, circular
dimples are often modified to a slightly elliptical shape. For the
purposes of this invention, these dimples are considered to be
nominally the same as their unmodified counterparts.
[0030] While FIGS. 1-5 show the six (6) nominally identical
hemispheres that are produced with an octahedron dimple layout,
other dimple layouts would produce varying numbers. For example, an
icosidodecahedron pattern would have six (6) parting lines and
twelve (12) nominally identical hemispheres and a cuboctahedron
would produce four (4) parting lines and eight (8) nominally
identical hemispheres.
[0031] While it is apparent that the illustrative embodiments of
the invention disclosed herein fulfill the objectives stated above,
it is appreciated that numerous modifications and other embodiments
may be devised by those skilled in the art. Therefore, it will be
understood that the appended claims are intended to cover all
modifications and embodiments, which would come within the spirit
and scope of the present invention. The dimple patterns of the
present invention can be used with any type of golf ball with any
playing characteristics. For example, the dimple pattern can be
used with conventional golf balls, solid or wound. These balls
typically have at least one core layer and at least one cover
layer. Wound balls typically have a spherical solid rubber or
liquid filled center with a tensioned elastomeric thread wound
thereon. Wound balls typically travel a shorter distance, however,
when struck as compared to a two piece ball. The cores of solid
balls are generally formed of a polybutadiene composition. In
addition to one-piece cores, solid cores can also contain a number
of layers, such as in a dual core golf ball. Covers, for solid or
wound balls, are generally formed of ionomer resins, balata, or
polyurethane, and can consist of a single layer or include a
plurality of layers and, optionally, at least one intermediate
layer disposed about the core.
[0032] All of the patents and patent applications mentioned herein
by number are incorporated by reference in their entireties.
[0033] While the preferred embodiments of the present invention
have been described above, it should be understood that they have
been presented by way of example only, and not of limitation. It
will be apparent to persons skilled in the relevant art that
various changes in form and detail can be made therein without
departing from the spirit and scope of the invention. Thus the
present invention should not be limited by the above-described
exemplary embodiments, but should be defined only in accordance
with the following claims and their equivalents.
* * * * *