Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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PATENT
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GOLF BALL WITH COVER HAVING VARYING HARDNESS
BACKGROUND
[0001] The present invention relates generally to a golf ball, and a method of
manufacturing the golf ball. In particular, a cover layer on the golf ball
includes areas
having a higher hardness and areas having a lower hardness.
[0002] The game of golf is an increasingly popular sport at both the amateur
and professional levels. A wide range of technologies related to the
manufacture and
design of golf balls are known in the art. Such technologies have resulted in
golf balls
with a variety of play characteristics. For example, different golf balls are
manufactured
and marketed to players having different golfing abilities, such as different
swing speeds.
[0003] Similarly, a golfer may use different golf balls having different play
characteristics depending on the golfer's preferences. For example, different
dimple
patterns may affect the aerodynamic properties of the golf ball during flight,
or a
difference in the hardness of the cover layer may affect the rate of backspin.
With
regard to hardness in particular, a golfer may choose to use a golf ball
having a cover
layer and/or a core that is harder or softer. A golf ball with a harder cover
layer will
generally achieve reduced driver spin, and achieve greater distances. However,
a
harder cover layer will generally cause a lower rate of spin, such that the
golf ball will be
better for drives but more difficult to control on shorter shots. On the other
hand, a golf
ball with a softer cover will generally experience more spin and therefore be
easier to
control and stop on the green, but will lack distance off the tee.
[0004] A wide range of golf balls having a variety of hardness characteristics
are known in the art. Generally, the hardness of a golf ball is determined by
the
chemical composition and physical arrangement of the various layers making up
the
golf ball. Accordingly, a number of different golf ball materials are mixed
and matched
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in various combinations and arrangements to create golf balls having different
hardness
values and different hardness profiles.
[0005] However, designing golf balls to achieve desired hardness
characteristics suffers from at least several difficulties. Generally, the
construction of
known golf balls requires that a wide range of design variables such as layer
arrangement, materials used in each layer, and layer thickness be balanced
against
each other. Changes to any of these variables may therefore improve a desired
hardness only at the expense of other play characteristics. Additionally,
materials costs
and design costs associated with known golf ball constructions may unduly
increase the
cost of the golf ball to the end consumer. Perhaps most importantly, known
golf balls
generally cannot simultaneously achieve the advantageous play characteristics
associated with high cover hardness (greater distances) while also achieving
the
advantageous play characteristics associated with low cover hardness (greater
spin).
[0006] Therefore, there is a need in the art for a system and method that
addresses the shortcomings of the prior art discussed above.
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SUMMARY
[0007] In one aspect, the invention provides a golf ball comprising a core;
and
a cover layer, the cover layer substantially surrounding the core and
including a plurality
of dimples and at least one land area separating the dimples; the cover layer
including a
first portion, the first portion of the cover layer having a first hardness
and at least one
dimple thereon, and a second portion, the second portion of the cover layer
having a
second hardness and at least a part of the at least one land area thereon;
wherein the
first portion and the second portion are non-overlapping portions of a
continuous cover
layer material; and the first hardness is higher than the second hardness.
[0008] In another aspect, the present disclosure provides the above
mentioned golf ball, wherein the first portion of the cover layer has a first
degree of
crystallinity, the second portion of the cover layer has a second degree of
crystallinity,
and the first degree of crystallinity is higher than the second degree of
crystallinity.
[0009] Furthermore, the present disclosure provides a golf ball comprising: a
core; and a cover layer substantially surrounding the core, the cover layer
being formed
of a material having a first hardness, and the cover layer having a plurality
of dimples
and at least one land area thereon; the plurality of dimples being arranged on
the cover
layer in a first pattern; the at least one land area being arranged on the
cover layer in a
second pattern, the first pattern and the second pattern being non-overlapping
patterns;
wherein the cover layer is coated with a coating material having a second
hardness
such that the coating material overlaps at least a portion of one of the first
pattern and
the second pattern but substantially does not overlap the other of the first
pattern and
the second pattern; and wherein the second hardness is different from the
first hardness.
[0010] Finally, the present disclosure also provides a method of
manufacturing a golf ball, the method comprising the steps of. (1) receiving a
golf ball
having a core and a cover layer substantially surrounding the core, the cover
layer
having a plurality of dimples and at least one land area separating adjacent
dimples, the
plurality of dimples being arranged on the cover layer in a first pattern, the
at least one
land area being arranged on the cover layer in a second pattern; (2) coating
the cover
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layer with a coating material over at least a portion of at least one of the
first pattern and
the second pattern; and, if necessary, (3) selectively removing the coating
material from
the cover layer; whereby the coating material overlaps at least a portion of
one of the
first pattern and the second pattern but substantially does not overlap the
other of the
first pattern and the second pattern.
[0011] Other systems, methods, features and advantages of the invention will
be, or will become, apparent to one of ordinary skill in the art upon
examination of the
following figures and detailed description. It is intended that all such
additional systems,
methods, features and advantages be included within this description and this
summary,
be within the scope of the invention, and be protected by the following
claims.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The invention can be better understood with reference to the following
drawings and description. The components in the figures are not necessarily to
scale,
emphasis instead being placed upon illustrating the principles of the
invention.
Moreover, in the figures, like reference numerals designate corresponding
parts
throughout the different views.
[0013] FIG. 1 shows an exemplary golf ball before and after selective
treatment;
[0014] FIG. 2 shows a cross section of the golf ball, before and after the
selective treatment;
[0015] FIG. 3 shows a cross section of a golf ball having an alternative
dimple
pattern;
[0016] FIG. 4 shows a heating device that can be used to achieve selective
heating;
[0017] FIG. 5 shows a cross section of the golf ball and heating device,
before
and after heating;
[0018] FIG. 6 shows a cross section of a portion of the golf ball and a second
heating device, before and after heating;
[0019] FIG. 7 shows an exemplary golf ball before and after selective coating;
[0020] FIG. 8 shows a cross section of a portion of a golf ball cover layer,
before and after the selective coating;
[0021] FIG. 9 shows a cross section of a portion of a golf ball cover layer,
before and after a different selective coating;
[0022] FIG. 10 shows a cross section of a portion of a golf ball cover layer,
in
further detail;
[0023] FIG. 11 shows a close-up cross section of a portion of a golf ball
cover
layer, after a part of a selective coating has been removed;
[0024] FIG. 12 shows a second embodiment of a cross section of a portion of
a golf ball cover layer, in further detail;
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[0025] FIG. 13 shows a second embodiment of a close-up cross section of a
portion of a golf ball cover layer, after a part of a selective coating has
been removed;
[0026] FIG. 14 is a flowchart detailing a method of manufacturing a golf ball,
including optional steps;
[0027] FIG. 15 shows a golfer about to hit a golf ball with a driver, and a
detailed view of the golf ball prior to being hit by the driver;
[0028] FIG. 16 shows the golfer hitting a golf ball with a driver, and two
detailed views of the golf ball as it is being hit by the driver; and
[0029] FIG. 17 shows the golfer hitting a golf ball with a iron, and two
detailed
views of the golf ball as it is being hit by the iron.
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DETAILED DESCRIPTION
[0030] Generally, the present disclosure relates to a golf ball having areas
on
the cover layer that are relatively hard and areas on the cover layer that are
relatively
soft. The relatively hard areas correspond to at least some of the dimples in
the cover
layer, and the relatively soft areas correspond to at least part of at least
one land area
between the dimples. As a result of the arrangement of the hard dimples and
the soft
land area(s), the golf ball experiences a lower rate of spin when struck with
a larger
force (such as during a dive) while also experiencing a higher rate of spin
and increased
control when struck with a smaller force (such as during a chip). The golf
ball therefore
achieves improved play characteristics associated with harder cover layers
(such as
longer distance) during drives, while also achieving improved play
characteristics
associated with softer cover layers (such as higher spin) during short shots.
[0031] This disclosure further relates to methods of manufacturing such a golf
ball.
[0032] FIG. 1 shows an exemplary golf ball 100 in accordance with this
disclosure. Golf ball 100 is made up of a cover layer having thereon a
plurality of
dimples 104 and at least one land area 106. Golf ball 100 may generally be any
type of
golf ball having a core and a cover layer substantially surrounding the core.
For
example, golf ball 100 may be of a two-piece construction, having only a core
and a
cover layer, or golf ball 100 may have one or more intermediate layers located
between
the core and the cover layer. Except as otherwise herein discussed, each layer
of golf
ball 100 may be formed of any material or construction as is generally known
in the art
of golf ball manufacturing. For example, various layers of golf ball 100 may
be
comprised of rubber, rubber composites, thermoplastic polyurethane, highly-
neutralized
polymers, ionomers, and other polymer materials as are known in the art of
golf ball
manufacturing.
[0033] The plurality of dimples 104 may generally be arranged on the cover
layer in any pattern, as may be known in the art of golf balls. Various known
dimple
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packing patterns are known in the art. Dimples 104 may generally be of any
shape,
such as circular, triangular, or multi-sided. Dimples 104 may be of uniform
shape and
size, or the dimple pattern may be made up of two or more different types of
dimples
having (for example) different sizes or different shapes. At least one land
area 106 is a
part of the cover layer that separates at least two dimples 104 and that is
not indented
or otherwise part of a dimple. Generally, land area 106 is the "ridge" or
"fret" between
adjoining dimples 104. Golf ball 100 may include one continuous land area 106
across
the entire cover layer, as is shown in FIG. 1, or a plurality of separate land
areas
between the plurality of dimples 104.
[0034] As shown in FIG. 1, golf ball 100 undergoes selective treatment of land
area 106. In the embodiment shown in FIG. 1, the selective treatment changes
the
entirety of land area 106 from a first state into land area 108 in a second
state. In other
embodiments, the selective treatment may be applied to a portion of land area
106.
This selective treatment may comprise a heating step, discussed in further
detail below.
[0035] FIG. 2 shows a cross section of golf ball 100, before and after the
selective treatment. In particular, golf ball 100 includes core 202 and cover
layer 200.
Cover layer 200 includes dimples 104 and land areas 106 thereon. Prior to the
selective treatment, cover layer 200 is made up of several sections 204 having
at least
one dimple 104 thereon, and several sections 206 having at least a part of at
least one
land area 106 forming the top boundary thereof. After the selective treatment,
the
sections 206 having a part of at least one land area 106 thereon are changed
into a
second state 208 as discussed above with respect to land areas in a second
state 108.
[0036] After the selective treatment, cover layer 200 generally includes a
first
portion having a first hardness, and a second portion having a second
hardness. The
first portion generally includes those sections 204 of cover layer 200 having
at least one
dimple 104 thereon. The first portion may include all sections 204 of cover
layer 200
having dimples 104 thereon, or the first portion may include some of the
sections 204
but not others. In other words, the first portion as a whole may include all
of the dimples
104 thereon, or a subset of fewer than all of the plurality of dimples 104
thereon.
Generally, the first portion of cover layer 200 can be made up of any number
and
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arrangement of the sections 204. Similarly, the second portion of cover layer
200
generally includes those sections 208 having at least a part of at least one
land area
108 thereon. The second portion may also be made up of all sections 208, or
fewer
than all of the sections 208. In other words, the second portion as a whole
may include
the entirety of all of the land area(s) thereon, or may include less than the
entirety of all
of the land area(s) thereon.
[0037] Either of the first or the second portion may extend through the entire
cross-sectional thickness of the cover layer 200, as shown in FIG. 2, or only
though a
portion of the cross section of cover layer 200, as shown in FIG. 5. Referring
again to
FIG. 2, specifically, the second portion may extend from an outer surface 250
of cover
layer 200 to an inner surface 252 of cover layer 200. Alternatively, as shown
in FIG. 5,
the second portion may extend from an outer surface 250 of the cover layer 200
to an
intermediate point 254 between the outer surface 250 and the inner surface 252
of
cover layer 200.
[0038] Each of the first portion and the second portions are non-overlapping
portions of a continuous cover layer material. Namely, as shown in FIG. 2, the
portions
204 and the portions 206 are defined by the dimples 104 and the land 106 but
are
otherwise parts of the same continuous cover layer 200. In particular
embodiments, the
first portion and the second portion of cover layer 200 have the same material
composition, i.e. there is no difference in the chemical composition of the
materials
making up the first portion and the second portion.
[0039] The first hardness, associated with the first portion of cover layer
200,
is higher than the second hardness, associated with the second portion of
cover layer
200. Accordingly, the portions of cover layer 200 associated with dimples 104
are
generally relatively hard, while the portions of cover layer 200 associated
with land
areas 108 are generally relatively soft. The degree of difference in hardness
between
the first portion and the second portion may be any non-trivial difference in
hardness. In
certain embodiments, the hardness of the first portion may be at least about 3
units on
the Shore D scale harder than the hardness of the second portion. In other
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embodiments, the first potion may be at least about 5 units on the Shore D
scale harder
than the second portion.
[0040] Generally, the present disclosure encompasses two or more zones of
differing hardness of the cover layer. For example, a golf ball may have three
zones of
hardness. In such an embodiment, cover layer 200 includes a third portion. The
first
portion, the second portion, and the third portion are all non-overlapping
portions of the
continuous cover layer material.
[0041] For example, a second embodiment of a dimple pattern that may be
used in conjunction with the present disclosure is shown in FIG. 3. In this
embodiment,
cover layer 200 again includes dimples 104 and land areas 106 separating at
least two
dimples 104. Here, each dimple 104 is made up of a center dimple section 152
and a
radial edge dimple section 150. Cover layer 200 includes portions 206
underlying the
land areas (as in the embodiment shown in FIG. 2, discussed above), portions
214
underlying radial edge dimple sections 150, and portions 216 underlying center
dimple
sections 152. Portions 214 and 216 are collectively equivalent to portion 204
in the
embodiment shown in FIG. 2, discussed above.
[0042] This cover layer 200 as shown in FIG. 3 may then undergo selective
treatment so as to change the hardness of certain portions of the cover layer.
Specifically, first, portions 206 may undergo selective treatment so as to
change into
portions 208 in a second state. Portions 208 thereby achieve a second
hardness, as
discussed above. Furthermore, portions 216 also undergo selective treatment so
as to
change into portions 218 in a second state. Portions 218 have a third
hardness. The
third hardness may be different from or equal to the second hardness. Finally,
portions
214 may remain unchanged, and have a fourth hardness. The fourth hardness may
be
greater than the third hardness. Accordingly, after undergoing selective
treatment,
cover layer 200 achieves three zones of hardness: land areas 106 having a
second
hardness, center dimple sections 152 having a third hardness, and radial edge
dimple
section 150 having a fourth hardness. In this case, the "first portion"
discussed above
includes at least one dimple 104 having a center dimple section 152 and a
radial edge
dimple section 150, and the "first hardness" discussed above may be considered
as the
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effective average of the third hardness and the fourth hardness based on the
relative
proportions of center dimple section 152 and radial edge dimple section 150 in
the
dimple 104.
[0043] Cover layer 200 is generally made of any material that can change in
hardness in response to a selective treatment. In particular embodiments where
the
selective treatment comprises heating, cover layer 200 may comprise a phase
transition
material as described in U.S. Patent Application Publication No. 2008/0081710
(hereinafter referred to as "the `710 Publication"). Specifically, the phase
transition
material described in the `710 Publication is an acid copolymer that comprises
copolymerized residues of at least one alpha olefin having from two to six
carbon atoms
and copolymerized residues of at least one a,R-ethylenically unsaturated
carboxylic acid
having from 3 to 8 carbon atoms.
[0044] As described in the `710 Publication, this phase transition material
changes hardness in response to heating. Specifically, heat energy decreases
the
hardness by disrupting the material's secondary crystal structure. As is
generally
known in the arts of polymer science, the hardness of a semi-crystalline
polymer
material can be proportional to the degree of crystallinity of the polymer
material. The
degree of crystallinity is the amount of the material that is in a crystalline
phase, as
compared to the amount of the material that is in an amorphous phase. The
crystalline
phase is generally harder than the amorphous phase, due to the close-packing
crystal
structure of the polymer molecules therein.
[0045] Therefore, golf ball 100 may be heated in a heating device 600 as
shown in FIG. 4 in order to achieve the desired difference in hardness. The
heating
device 600 is fully described in U.S. Patent Application Publication No.
2011/0095012.
Heating device 600 is held by a user's hand 602 and moved, as shown, such that
heating surface 106 is brought into contact with the golf ball 100.
[0046] Specifically, as shown in FIG. 5, cover layer 200 may be selectively
heated by a heating element 606 in order to achieve the desired difference in
hardness.
Specifically, heating element 606 may be brought into contact with the land
areas 106 of
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cover layer 200. The sections of cover layer 200 closest to the surface of
land areas
106 touching heating element 606 are therefore heated. These sections form the
second portion of the cover layer, as described above. In the embodiment
described
here, and as shown in FIG. 5, the second portion extends from the outer
surface 250 of
the cover layer 200 to an intermediate point 254 between the outer surface 250
and the
inner surface 252, depending on the nature and extent of the heat applied by
the
heating element 606. As a result of the selective heating applied to the land
areas 106,
the first portion of cover layer 200 (encompassing untreated sections 204) has
a first
hardness that is higher than the second hardness of the second portion
(encompassing
treated sections 208). Specifically, the secondary crystal structure of the
second portion
has been disrupted, and so the degree of crystallinity of the first portion is
higher than
the degree of crystallinity of the second portion.
[0047] Although FIG. 5 only shows this selective heating process being
applied to a particular cross section of the cover layer 200, this selective
heating
process may be applied to the entire surface of golf ball 100, such that all
land areas
106 are heated. Alternatively, the selective heating process may be applied to
certain
land areas 106 on different locations on golf ball 100, but not others, as may
be desired.
In either case, the second portion of cover layer 200 will encompass only
those portions
of cover layer 200 that are heated, and therefore have a difference in
hardness from the
first portion of cover layer 200.
[0048] In another embodiment, the cover layer 220 may comprise a semi-
crystalline thermoplastic material. Methods for changing the hardness of semi-
crystalline thermoplastic materials are fully described in U.S. Patent
Application
Publication No. 2011/0177890.
[0049] Specifically, as is shown in FIG. 6, heating element 608 may be used
to heat sections 210 of the cover layer 220 associated with the dimples 104.
In
accordance with the methods described in the `493 Application, these sections
210 may
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be heated to increase the movement of the polymer molecules in the semi-
crystalline
thermoplastic material, and subsequently slowly cooled such that the degree of
crystallinity in these sections 210 increases. Sections 210 therefore
collectively make
up the first portion of cover layer 200, as described above, and have a
hardness that is
higher than the un-heated sections 212 collectively making up the section
portion. In
such embodiments, again, the degree of crystallinity of the first portion of
cover layer
200 is higher than the degree of crystallinity of the second portion. In other
words, the
first portion has a first degree of crystallinity, and the second portion has
a second
degree of crystallinity, where the first degree of crystallinity is higher
than the second
degree of crystallinity.
[0050] The heating element 606, or heating element 608, used in the methods
described above may generally be any heating mechanism that is capable of
selectively
heating the desired portions of the cover layer. In a particular embodiment,
as
mentioned above and shown in FIG. 4, the heating element may be a component of
the
heating apparatus described fully in U.S. Patent Application Serial No.
12/604,830
(hereinafter referred to as "the '830 Application"). In such embodiments, the
heating
element 606 or the heating element 608 may be the internal heating surface as
described in the '830 Application. Similarly, the heating element backing 604,
shown in
FIGS. 5 and 6, may be the external housing described in the '830 Application.
The
device described in the '830 Application allows a consumer to create a desired
difference in hardness in accordance with the present disclosure through the
use of a
particular pattern on the internal heating surface.
[0051] In different embodiments than those discussed variously above, the
difference in hardness between the dimples and the land areas can be achieved
through the use of a coating material. FIG. 7 shows a golf ball 300 in
accordance with
these embodiments, and a general process for making such a golf ball.
Generally, a
golf ball 300 may comprise a core and a cover layer substantially surrounding
the core,
where the cover layer is formed of a material having a first hardness and has
a plurality
of dimples 304 and at least one land area 306 thereon. The plurality of
dimples 304
may be arranged on the cover layer in a first pattern, and the at least one
land 306 area
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may be arranged on the cover layer in a second pattern, where the first
pattern and the
second pattern are non-overlapping patterns. Then, the cover layer may be
coated with
a coating material 308 having a second hardness, such that coating material
308
overlaps at least a portion of one of the first pattern and the second
pattern, but
substantially does not overlap the other of the first pattern and the second
pattern. The
second hardness is different from the first hardness.
[0052] In the embodiment shown in FIG. 7, the coating material 308 is
selectively applied on the first pattern corresponding to the dimples 304. In
such an
embodiment, the second hardness (i.e., the hardness of the coating material)
is higher
than the first hardness (i.e., the hardness of the cover material). Therefore,
coating
material 308 makes the dimples 304 hard while the cover layer, exposed on the
land
areas 306, is soft. Although FIG. 7 shows all of the dimples 304 being coated
with the
coating material 308, coating material 308 may alternatively coat only a
portion of the
first pattern.
[0053] FIG. 8 shows a cross-sectional view of the dimples 304 and land areas
306 shown in FIG. 6. In FIG. 8, coating material 308 is coated on top of each
of the
dimples 304, forming a thin layer of coating material 308 on a cover layer
302. The
thickness of the coating material 308 may generally be any thickness that fits
within a
dimple. Coating material 308 should generally not be so thick as to
significantly affect
the aerodynamics of the golf ball, however coating material 308 may be applied
in such
a way as to achieve a desired dimple depth configuration. In certain
embodiments,
cover layer 302 may have a thickness of about 2 mm or less. Accordingly, in
these
embodiments coating material 308 may have a thickness that is, for example, on
the
order of 0.5 mm or less, or 0.3 mm or less, or 0.1 mm or less.
[0054] FIG. 9 shows another embodiment, wherein land areas 306 are coated
with a coating material 310. In this embodiment, coating material 310 covers
at least a
part of the second pattern, the second pattern corresponding to the land areas
306. As
mentioned above with respect to the embodiment in FIG. 8, in the embodiment of
FIG. 9
coating material 310 may generally cover all of the second pattern or less
than all of the
second pattern in any arrangement as may be desired. In embodiments where
coating
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material 310 covers at least a part of the second pattern, the second hardness
(i.e., the
hardness of coating material 310) is less than the hardness of the cover layer
material.
Accordingly, land areas 306 coated with coating material 310 are relatively
soft, while
dimples 104 are relatively hard.
[0055] FIGS. 10 and 11 show a further feature of the coating that may be
used in conjunction with any of the above discussed embodiments. Specifically,
FIG.
shows several pockets 312 in the surface of the cover layer 302. Although FIG.
10
shows pockets 312 as being located on cover layer 302 corresponding to land
area 306,
pockets 312 may equally be located on cover layer 302 corresponding to dimples
304,
as shown in FIGS. 12 and 13. Generally, pockets 312 are small indentations or
abrasions intentionally formed in the surface of cover layer 302. Pockets 312
generally
have a depth 320 that is at least less than the depth of dimple 304, and, in
some
embodiments, significantly less than the depth of dimples 304. In embodiments
where
cover layer 302 has a thickness of about 2.0 mm, the pockets 312 may have a
depth
320 of less than about 0.5 mm, less than about 0.3 mm, or less than about 0.1
mm.
Pockets 312 may enable coating material 308, 310 to better adhere to cover
layer 302.
Pockets 312 may also allow more flexibility in the design of the golf ball,
such as by
achieving a desired difference in hardness without, for example, changing the
dimple
depth or total diameter of the golf ball.
[0056] When coating material 310 is coated on cover layer 302 having
pockets 312 therein, coating material 310 fills the pockets 312 as well as
coats the
surface of cover layer 302 with a top section 314 of coating material 310. The
top
section 314 of coating material 310 may be left in place on the second pattern
on top of
land areas 306, if desired, or may be removed to leave coating material 310
only in the
pockets 312. FIG. 11 show coating material present only the pockets 312. As
shown in
FIG. 11, the coating material is located in the pockets, but does not
otherwise
substantially overlap the surface of cover layer 302.
[0057] FIGS. 12 and 13 show an embodiment wherein pockets 316 are made
in the surface of cover layer 302 located on dimple 304. Similar to as
discussed above,
coating material 308 may include a top section 318 as well as fill the pockets
316. The
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top section 318 of coating material 308 may then be removed, if so desired,
leaving
coating material 308 only in pockets 316. Pockets 316 in dimple 304 have a
depth 322
that may be the same as or different from depth 320 of pockets 312 associated
with
land area 306.
[0058] In these embodiments including pockets 312 and/or pockets 316,
generally, the coating material may be used to change the hardness of the
second
pattern in accordance with this disclosure, without changing the diameter or
aerodynamic performance of the golf ball. Therefore a wider range of golf ball
designs
may be used in accordance with the present disclosure, without the need to
redesign
the physical structure of the golf ball or sacrifice advantageous aerodynamic
properties.
[0059] The coating material may generally be selected in accordance with the
desired hardness. In embodiments, such as are shown in FIG. 7 and 8, wherein
the
coating material has a hardness higher than the hardness of the cover layer
material,
the coating material may be a hard polymer or a metal plating. A wide range of
polymers are known in the art that have high hardness values. The hardness of
a
polymer material may generally be controlled by, for example, the degree of
cross-
linking, the degree of crystallinity, and the chain length. In a specific
embodiment, for
example, the cover layer material may be a thermoplastic polyurethane (TPU)
having a
hardness of about 45 to 60 on the Shore D scale, and the coating material may
be a
thermoplastic polyurethane having a hardness of about 65 on the Shore D scale.
Generally, the polymer coating material may be any thermoplastic, thermoset,
ionomer,
copolymer, or other polymer material known and used in the art of golf balls.
[0060] Additionally, the coating material may be a metal plating. Nearly any
typical metal may be used, as most metals have a hardness at conventional
temperatures that is higher than polymer materials conventionally used to form
golf ball
cover layers. Exemplary metals that may be used as the coating material
include
aluminum, steel, tungsten, titanium, magnesium, and iron alloys, among a
variety of
others. The metal coating material may be selected based on hardness,
workability,
and cost effectiveness.
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[0061] FIG. 14 is a flowchart detailing a method of manufacturing the golf
ball
discussed above, including optional steps. Generally, a method 700 of
manufacturing a
golf ball includes first step 702 of receiving a golf ball having a core and a
cover layer
with a plurality of dimples and at least one land area thereon. The golf ball
may then
undergo an optional preliminary step of treating the cover layer so as to
create pockets
312 in the cover layer. This preliminary treatment step may be, for example, a
physical
surface roughening, or a chemical etching that etches only a small portion of
the cover
layer such as an unmasked portion of the surface of the golf ball.
[0062] Next, method 700 of manufacturing the golf ball may take either of two
general routes. In a first step 706 of a first route, the entire cover layer
is coated with
the coating mater. The coating may be a physical coating step, such as by
brushing,
dipping, spraying or other physical application means. Alternatively, the
coating may be
a chemical coating step, such as chemical vapor deposition (CVD), plasma spray
coating, or other chemical application means. The coating material is then
selectively
removed in step 708, such that the coating layer remains only on either of the
first or
second pattern, as desired. The removal of the coating material may be a
physical
grinding away of the coating, or may be a chemical removal such as by chemical
etching using a mask to protect selected coated areas to prevent the removal
of
selected coated areas.
[0063] Alternatively, in step 710 a mask may be applied over the golf ball.
The mask may be a physical mask having a pattern of holes corresponding to
either of
the first pattern or the second pattern. The coating material is then 712
applied on top
of the mask, after which 714 the mask is removed, leaving the coating material
on only
the pattern corresponding to the holes in the mask.
[0064] Finally, if the golf ball underwent step 704 to create pockets, the
surface portion of the coating material 314 may be removed in step 716. This
step
leaves the coating material in only the pockets, and not otherwise
substantially
overlapping the surface of the cover layer.
[0065] Although not wishing to be bound by any particular theory of action, it
is believed that the golf ball of the present disclosure achieves superior
play
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characteristics due to the interaction between a golf club face and the golf
ball as is
shown in FIGS. 14-16.
[0066] In FIG. 15, a golfer 400 swings a golf club 402 toward golf ball 100.
It
is noted that golf ball 100 is referenced here, however the same results are
achieved by
golf ball 300. The golf club 402 is a driver, having a large club head 404,
and a club
face 406 that is wide and has a low loft angle. As seen in the zoomed-in
section of FIG.
12, the golf ball 100 includes dimples 104 and land area 108 (as in FIG. 1).
[0067] In FIG. 16, the club face 406 strikes the golf ball 100 with a large
amount of force, in accordance with a drive. The golf ball 100 therefore
deforms, as is
shown in the first zoom-in section. Specifically, the golf ball 100 deforms
such that a
first area 550 of the golf ball cover layer is flat against the club face 406.
In first area
550, the club face 406 impacts both the land areas and the dimples,
compressing them
against core 202 (and any inner layers). In this first area 550 where both the
hard
dimples 104 and the soft land 108 are flat against the club face, the cover
layer
"appears" to have a hardness that is between the hardness of the dimples and
the
hardness of the land (depending on the ratio of each). By "appears" is meant:
how the
club face 406 interfaces with the cover layer in this area.
[0068] In particular, as seen in the second zoomed-in section of FIG. 16, at
the periphery of first area 550, the club face impacts the land while
impacting the
dimples to varying degrees. Specifically, first dimple 500 is not impacted at
all, while
first land area 510 is impacted to a slight degree. Second dimple 502 is
impacted only
slightly, as shown by the difference between the present shape of dimple 502
and the
original shape denoted by outline 506, because the first land 510 and second
land 512
are partially but not entirely compressed. Similarly, third dimple 504 is also
impacted
somewhat but not entirely, as shown by outline 508. Therefore, during a golf
shot
involving a high degree of force (such as a drive), the golf ball 100
undergoes
compression such that the club face touches at least some of the relatively
hard
surfaces of the dimples.
[0069] FIG. 17 shows a different type of golf shot in action. In FIG. 17 the
golf
club 410 is, for example, an iron. Club head 412 on iron 410 has a higher loft
angle, as
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seen by the angle of the club face 406 in the first zoomed-in section of FIG.
17. In this
scenario, the golf ball is hit with less force than in FIG. 16. Therefore,
golf ball 100 does
not compress against club face 406 so as to deform the dimples, as shown in
the first
zoomed-in section of FIG. 17. FIG. 17 shows a periphery of the deformed second
area
560, where club face 406 again impacts first land 510 and second land 512, but
in this
case does not deform first dimple 500, second dimple 502, or third dimple 504.
Therefore, the apparent hardness of the cover layer is lower, as compared to
the
apparent hardness of the cover layer under compression shown in FIG. 16,
because the
club face 406 only touches relatively soft land areas 108 without also
touching the
relatively hard surfaces of dimples 104.
[0070] Thus, the present golf ball appears to be softer when hit with less
force,
but harder when hit with more force. Thereby, the present golf ball achieves
improved
play characteristics associated with harder cover layers (such as longer
distance) during
drives, while also achieving improved play characteristics associated with
softer cover
layers (such as higher spin) during short shots. Furthermore, golf balls made
in
accordance with this disclosure may also simultaneously achieve improved play
characteristics that are unrelated to the hardness.
[0071] While various embodiments of the invention have been described, the
description is intended to be exemplary, rather than limiting and it will be
apparent to
those of ordinary skill in the art that many more embodiments and
implementations are
possible that are within the scope of the invention. Accordingly, the
invention is not to
be restricted except in light of the attached claims and their equivalents.
Also, various
modifications and changes may be made within the scope of the attached claims.
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