U.S. patent application number 12/955329 was filed with the patent office on 2011-03-24 for article of footwear having midsole with support pillars and method of manufacturing same.
This patent application is currently assigned to NIKE, Inc.. Invention is credited to Michael A. Calvano, Paul Caron, Gerald Edwin Crowley, Michael Hui, Randall Wyszynski.
Application Number | 20110067263 12/955329 |
Document ID | / |
Family ID | 37496070 |
Filed Date | 2011-03-24 |
United States Patent
Application |
20110067263 |
Kind Code |
A1 |
Wyszynski; Randall ; et
al. |
March 24, 2011 |
Article of Footwear Having Midsole with Support Pillars and Method
of Manufacturing Same
Abstract
An article of footwear includes an upper, a sole assembly, and a
support assembly positioned in the sole assembly and including a
plurality of pillars. Each pillar includes an outer layer and an
inner layer of cushioning material contained with the outer
layer.
Inventors: |
Wyszynski; Randall; (Lake
Oswego, OR) ; Calvano; Michael A.; (Tualatin, OR)
; Crowley; Gerald Edwin; (Beaverton, OR) ; Caron;
Paul; (Hillsboro, OR) ; Hui; Michael; (Lake
Oswego, OR) |
Assignee: |
NIKE, Inc.
Beaverton
OR
|
Family ID: |
37496070 |
Appl. No.: |
12/955329 |
Filed: |
November 29, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12632305 |
Dec 7, 2009 |
7841105 |
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12955329 |
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12138744 |
Jun 13, 2008 |
7644462 |
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12632305 |
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11206254 |
Aug 17, 2005 |
7401418 |
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12138744 |
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Current U.S.
Class: |
36/28 |
Current CPC
Class: |
B29C 39/025 20130101;
B29L 2031/504 20130101; A43B 13/181 20130101; B29C 39/006 20130101;
B29C 39/10 20130101; B29D 35/142 20130101; B29C 39/12 20130101 |
Class at
Publication: |
36/28 |
International
Class: |
A43B 13/18 20060101
A43B013/18 |
Claims
1. An article of footwear comprising, in combination: an upper; a
sole assembly; and a support assembly positioned in the sole
assembly and including a plurality of pillars, each pillar
comprising an outer layer and an inner layer of cushioning material
contained within the outer layer such that the entire outer layer
completely circumferentially surrounds the inner layer,
substantially without any voids between the inner layer and the
outer layer.
2. The article of footwear of claim 1, wherein the outer layer
includes a plurality of recesses formed of walls and a bottom, the
inner layer of cushioning material being received in each
recess.
3. The article of footwear of claim 2, wherein at least one recess
has four walls.
4. The article of footwear of claim 2, wherein at least one recess
has three walls.
5. The article of footwear of claim 2, wherein the walls of at
least one recess taper inwardly to the bottom of the at least one
recess.
6. The article of footwear of claim 1, wherein the outer layer is
formed of TPU.
7. The article of footwear of claim 1, wherein the cushioning
material is formed of polyurethane.
8. An article of footwear comprising, in combination: an upper; a
sole assembly; and a support assembly positioned in the sole
assembly and including a plurality of pillars, each pillar
comprising an outer layer including a recess formed of walls and a
bottom, and an inner layer of cushioning material contained within
the recess such that the entire outer layer completely
circumferentially surrounds the inner layer without any voids
between the inner layer and the outer layer.
9. The article of footwear of claim 8, wherein at least one recess
has four walls.
10. The article of footwear of claim 8, wherein at least one recess
has three walls.
11. The article of footwear of claim 8, wherein the walls of at
least one recess taper inwardly to the bottom of the at least one
recess.
12. The article of footwear of claim 8, wherein the outer layer is
formed of TPU.
13. The article of footwear of claim 8, wherein the cushioning
material is formed of polyurethane.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of application Ser. No.
12/632,305, filed Dec. 7, 2009, which is a divisional of
application Ser. No. 12/138,744, filed Jun. 13, 2008, now U.S. Pat.
No. 7,644,462, issued Jan. 12, 2010, which is a divisional of
application Ser. No. 11/206,254, filed on Aug. 17, 2005, now U.S.
Pat. No. 7,401,418, issued Jul. 22, 2008, each of which is
incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] This invention relates generally to an article of footwear,
and, in particular, to an article of footwear having a midsole with
support pillars positioned therein and a method of manufacturing
the same.
BACKGROUND OF THE INVENTION
[0003] A conventional article of athletic footwear includes two
primary elements, an upper and a sole structure. The upper provides
a covering for the foot that securely receives and positions the
foot with respect to the sole structure. In addition, the upper may
have a configuration that protects the foot and provides
ventilation, thereby cooling the foot and removing perspiration.
The sole structure is secured to a lower portion of the upper and
is generally positioned between the foot and the ground. In
addition to attenuating ground reaction forces (i.e., imparting
cushioning), the sole structure may provide fraction and control
foot motions, such as pronation. Accordingly, the upper and the
sole structure operate cooperatively to provide a comfortable
structure that is suited for a variety of ambulatory activities,
such as walking and running.
[0004] The sole structure of athletic footwear generally exhibits a
layered configuration that includes a comfort-enhancing insole, a
resilient midsole formed from a polymer foam material, and a
ground-contacting outsole that provides both abrasion-resistance
and fraction. The midsole is the primary sole structure element
that imparts cushioning and controls foot motions. Suitable polymer
foam materials for the midsole include ethylvinylacetate or
polyurethane that compress resiliently under an applied load to
attenuate ground reaction forces. Conventional polymer foam
materials are resiliently compressible, in part, due to the
inclusion of a plurality of open or closed cells that define an
inner volume substantially displaced by gas. The polymer foam
materials of the midsole may also absorb energy when compressed
during ambulatory activities.
[0005] It would be desirable to provide an article of footwear that
reduces or overcomes some or all of the difficulties inherent in
prior known devices. Particular objects and advantages will be
apparent to those skilled in the art, that is, those who are
knowledgeable or experienced in this field of technology, in view
of the following disclosure of the invention and detailed
description of certain embodiments.
SUMMARY
[0006] The principles of the invention may be used to advantage to
provide an article of footwear with support pillars. In accordance
with a first aspect, an article of footwear includes an upper, a
sole assembly, and a support assembly positioned in the sole
assembly and including a plurality of pillars. Each pillar includes
an outer layer and an inner layer of cushioning material contained
with the outer layer.
[0007] In accordance with another aspect, an article of footwear
includes an upper, a sole assembly, and a support assembly
positioned in a heel portion of the sole assembly and including a
plurality of pillars. Each pillar includes an outer layer having an
upper portion including a first recess formed of walls and a
bottom. A lower portion has a second recess formed of walls and a
top, with the bottom of the first recess and the top of the second
recess being in abutting relationship. An aperture extends through
the bottom of the first recess and the top of the second recess. An
inner layer of cushioning material is contained with the outer
layer and extends through the aperture.
[0008] In accordance with a further aspect, a method of
manufacturing an article of footwear includes the steps of forming
a fluid-filled bag having a plurality of apertures extending
therethrough with a first mold; inserting the fluid-filled bag into
a second mold; pouring a cushioning material into the second mold
to form a support assembly with cushioning material covering the
bag and extending through the apertures of the fluid-filled bag to
form pillars; removing the support assembly from the second mold;
cutting away a portion of the cushioning material about a periphery
of the support assembly; cutting away a portion of a periphery of
the fluid-filled bag to expose the pillars formed therein; and
securing the support assembly between an upper and an outsole to
form an article of footwear.
[0009] In accordance with yet another aspect, an article of
footwear formed by the steps of forming a fluid-filled bag in a
first mold and including a plurality of first recesses on a first
side thereof and having a bottom, a plurality of second recesses on
a second side thereof and having a top with a plurality of
apertures extending therethrough, with each aperture extending
through the bottom of a first recess and a top of a second recess;
inserting the fluid-filled bag into a second mold; pouring a
cushioning material into the second mold to form a support assembly
with cushioning material covering the bag and extending into the
recesses and through the apertures of the fluid-filled bag to form
pillars; removing the support assembly from the second mold;
cutting away a portion of the cushioning material about a periphery
of the support assembly; cutting away a portion of a periphery of
the fluid-filled bag to expose the pillars formed therein; and
securing the support assembly between an upper and an outsole to
form an article of footwear.
[0010] Substantial advantage is achieved by providing an article of
footwear with support pillars. In particular, certain embodiments
of the article of footwear with support pillars can provide
increased support, comfort and performance.
[0011] These and additional features and advantages disclosed here
will be further understood from the following detailed disclosure
of certain embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a perspective view of an embodiment of an article
of footwear.
[0013] FIG. 2 is a perspective view of a mold used to form a
fluid-filled bag used in the formation of a support assembly of the
article of footwear of FIG. 1.
[0014] FIGS. 3A-C are elevation views of the use of the mold of
FIG. 2 to form the fluid-filled bag used in the formation of the
support assembly of the article of footwear of FIG. 1.
[0015] FIG. 4 is a perspective view of the fluid-filled bag formed
in the mold of FIG. 2.
[0016] FIG. 5 is a perspective view of a mold used to form the
support assembly of the article of footwear of FIG. 1.
[0017] FIG. 6 is a perspective view of the support assembly formed
in the mold of FIG. 5, shown being trimmed to its final form.
[0018] FIG. 7 is a perspective view of the support assembly formed
in the mold of FIG. 5, shown in its final form.
[0019] FIG. 8 is a section view of a portion of a pillar of the
support assembly of FIG. 7.
[0020] FIG. 9 is a section view of a portion of a pillar of another
embodiment of the support assembly of FIG. 7.
[0021] FIG. 10 is a perspective view of another embodiment of the
fluid-filled bag formed in the mold of FIG. 2.
[0022] The figures referred to above are not drawn necessarily to
scale and should be understood to provide a representation of the
invention, illustrative of the principles involved. Some features
of the article of footwear depicted in the drawings have been
enlarged or distorted relative to others to facilitate explanation
and understanding. The same reference numbers are used in the
drawings for similar or identical components and features shown in
various alternative embodiments. Articles of footwear as disclosed
herein would have configurations and components determined, in
part, by the intended application and environment in which they are
used.
DETAILED DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS
[0023] The present invention may be embodied in various forms. A
preferred embodiment of an article of footwear 10 is shown in FIG.
1. Footwear 10 includes an upper 12 and a sole assembly 14 secured
to upper 12. Sole assembly 14 may be secured to upper 12 by
adhesive or any other suitable means. Footwear 10 has a medial, or
inner, side 13 and a lateral, or outer, side 15. For purposes of
general reference, footwear 10 may be divided into three general
portions: a forefoot portion 16, a midfoot portion 18, and a heel
portion 20. Portions 16, 18, and 20 are not intended to demarcate
precise areas of footwear 10. Rather, portions 16, 18, and 20 are
intended to represent general areas of footwear 10 that provide a
frame of reference during the following discussion.
[0024] Unless otherwise stated, or otherwise clear from the context
below, directional terms used herein, such as rearwardly,
forwardly, top, bottom, inwardly, downwardly, upwardly, etc., refer
to directions relative to footwear 10 itself. Footwear 10 is shown
in FIG. 1 to be disposed substantially horizontally, as it would be
positioned on a horizontal surface when worn by a wearer. However,
it is to be appreciated that footwear 10 need not be limited to
such an orientation. Thus, in the illustrated embodiment of FIG. 1,
rearwardly is toward heel portion 20, that is, to the left as seen
in FIG. 1. Naturally, forwardly is toward forefoot portion 16, that
is, to the right as seen in FIG. 1, and downwardly is toward the
bottom of the page as seen in FIG. 1. Top refers to elements toward
the top of the page as seen in FIG. 1, while bottom refers to
elements toward the bottom of the page as seen in FIG. 1. Inwardly
is toward the center of footwear 10, and outwardly is toward the
outer peripheral edge of footwear 10.
[0025] Sole assembly 14, which is generally disposed between the
foot of the wearer and the ground, provides attenuation of ground
reaction forces (i.e., imparting cushioning), traction, and may
control foot motions, such as pronation. As with conventional
articles of footwear, sole assembly 14 may include an insole (not
shown) located within upper 12, a midsole 22, and an outsole 24.
Midsole 22 is attached to upper 12 and functions as the primary
shock-attenuating and energy-absorbing component of footwear 10.
Midsole 22 may be secured to upper 12 by adhesive or other suitable
means. Suitable materials for midsole 22 include polymer foam
materials such as ethylvinylacetate or polyurethane, or any other
material that compresses resiliently. Outsole 24 is attached to the
lower surface of midsole 22 by adhesive or other suitable means.
Suitable materials for outsole 24 include polymers, e.g.,
polyether-block co-polyamide polymers (sold as Pebax.RTM. by
ATOFINA Chemicals of Philadelphia, Pa.), and nylon resins such as
Zyte.RTM., sold by Dupont. Other suitable materials for outsole 24
will become readily apparent to those skilled in the art, given the
benefit of this disclosure. In certain embodiments, sole assembly
14 may not include an outsole layer separate from midsole 22 but,
rather, the outsole may comprise a bottom surface of midsole 22
that provides the external traction surface of sole assembly
14.
[0026] Sole assembly 14 includes a support assembly 26, which
includes a plurality of pillars 25, described in greater detail
below. As shown in the embodiments illustrated herein, support
assembly 26 is positioned in heel portion 20 of footwear 10. It is
to be appreciated that support assembly 26 can be positioned in one
or more of heel portion 20, midfoot portion 18 and/or forefoot
portion 16. As illustrated here, support assembly 26 is configured
to span across footwear 10. However, it is to be appreciated that
support assembly 26 could be configured to be positioned only on
lateral side 15 or only on medial side 13 of footwear 10. In other
embodiments, support assembly 26 could have one portion extending
across footwear 10 with another portion positioned in only lateral
side 15 or medial side 13. Other configurations of support assembly
26 will become readily apparent to those skilled in the art, given
the benefit of this disclosure.
[0027] The formation of a fluid-filled bag 27 (seen in FIG. 4) for
use in forming support assembly 26 is shown in FIGS. 2-4. A first
mold 30, used to form fluid-filled bag 27 is seen in FIG. 2. First
mold 30 includes a first portion 32 having a first recess 34 formed
therein. A plurality of first projections 36 extend outwardly from
the bottom 38 of first recess 34. A post 40 extends outwardly from
each first projection 36. A first channel 41 extends between first
recess 34 and an exterior of first portion 32.
[0028] A second portion 42 of first mold 30 is joined to first
portion 32 by a hinge 43 and includes a second recess 44 formed
therein. A plurality of second projections 46 extend outwardly from
a bottom 48 of second recess 44. Each second projection 46 includes
an aperture 50 that receives a corresponding post 40 of first
portion 32 when first mold 30 is closed. A second channel 51
extends between second recess 44 and an exterior of second portion
42. Second channel 51 mates with first channel 41 of first portion
32 when first mold 30 is closed, providing an input port, as
described in greater detail below. First projections 36 and second
projections 46 combine to define first and second recesses 66, 72,
respectively, of fluid-filled bag 27, as described in greater
detail below.
[0029] First mold 30 is used to form fluid-filled bag 27 as seen in
FIGS. 3A-C. An injector 52 outputs a substantially tubular sheet of
material 54 downwardly in the direction of Arrow A from an aperture
56 formed therein. First mold 30 is then closed about sheet of
material 54. A needle 58 is then inserted into an input port 53
(formed by the mating of first channel 41 and second channel 51 of
first mold 30) in the direction of Arrow B and injects a fluid,
such as air, into first mold 30, forcing material 54 against the
inner surfaces of first mold 30 to form fluid-filled bag 27 (seen
in FIG. 4). In certain embodiments, a vacuum may be applied to the
exterior of sheet of material 54 within first mold 30.
[0030] Material 54 used to form fluid-filled bag 27 may be
thermoplastic polyurethane (TPU), polyurethane, polyester,
polyester polyurethane, polyether polyurethane, ethyl vinyl alcohol
copolymers (EVOH) or scrap material. Other suitable materials for
use in forming fluid-filled bag 27 will become readily apparent to
those skilled in the art, given the benefit of this disclosure.
[0031] As seen in FIG. 4, fluid-filled bag 27 is formed of an upper
portion 60 and a lower portion 62 joined by a parting line 64
created during the molding process by the junction of first portion
32 and second portion 42 of first mold 30. Upper portion 60
includes a plurality of first recesses 66 having one or more walls
68 and a bottom 70. Walls 68 of first recesses 66 may taper
inwardly toward bottom 70. First recesses 66 are formed by first
projections 36 of first portion 32 of first mold 30.
[0032] Lower portion 62 similarly has a plurality of second
recesses 72 having one or more walls 74 and a top 76, which is in
abutting relationship with bottom 70 of a corresponding first
recess 66. Walls 74 of second recesses 72 may taper inwardly toward
top 76. Second recesses 72 are formed by second projections 46 of
second portion 42 of first mold 30. During the molding process
described above with respect to FIGS. 3A-C, a bottom 70 of a first
recess 66 and a top 76 of a corresponding second recess 72 are
sealed with one another as first projections 36 and second
projections 46 sandwich sheet of material 54 therebetween. An
aperture 78 may extend through bottom 70 of a first recess 66 and
the corresponding top 76 of a second recess 72. Apertures 78 are
formed by projections 40 of first portion 32 of first mold 30.
[0033] In the embodiment illustrated, each first and second recess
66, 72 has a substantially triangular shape and, therefore,
includes three walls 68, 74, respectively. Consequently, first and
second projections 36, 46 have substantially triangular shapes as
well. It is to be appreciated that other shapes for first and
second recesses 66, 72 are considered to be within the scope of the
present invention, and that the number and configuration of the
walls for first and second recesses 66, 72 will vary accordingly.
Thus, for example, first and second recesses 66, 72 may have square
or rectangular shapes, which would require four walls 68, 74,
respectively. In such an embodiment, first and second projections
36, 46 of first mold 30 will naturally have corresponding square or
rectangular shapes. Other shapes and configurations for first and
second recesses 66, 72 and, naturally, first and second projections
36, 46 will become readily apparent to those skilled in the art,
given the benefit of this disclosure.
[0034] In other embodiments, fluid-filled bag 27 may be produced by
the well known thermoforming process, in which a pair of polymer
layers are heated and placed between a pair of mold portions. A
vacuum on the exterior of the layers and/or pressure between the
layers draws the layers into contours of the mold. The peripheries
of the layers are then pressed together to form a peripheral bond,
and various interior locations may also be pressed together to form
interior bonds, thereby forming fluid-filled bag 27.
[0035] In other embodiments, fluid-filled bag 27 may be
manufactured by a two-film technique, often referred to as
twin-sheet bonding, wherein two separate layers of elastomeric film
are formed to have the overall shape of the bag. The layers are
then welded together along their respective peripheries to form an
upper surface, a lower surface, and sidewalls of the bag, and the
layers are welded together at predetermined interior locations to
impart a desired configuration to the bag. That is, interior
portions of the layers are connected to form chambers of a
predetermined shape and size at desired locations. The bag is then
subsequently pressurized above ambient pressure by inserting a
nozzle or needle, which is connected to a fluid pressure source,
into a fill inlet formed in the bag. After the bag is pressurized,
the nozzle is removed and the fill inlet is sealed, by welding for
example.
[0036] In other embodiments, fluid-filled bag 27 may be produced by
the well known blowmolding process, in which a liquefied
elastomeric material is placed in a mold having the desired overall
shape and configuration of fluid-filled bag 27. Pressurized air is
provided through an opening formed in the mold. The pressurized air
forces the liquefied elastomeric material against the inner
surfaces of the mold and causes the material to harden in the mold,
thereby forming the fluid-filled bag 27 having the desired
configuration.
[0037] In certain embodiments, fluid-filled bag 27 may be colored
to provide a desired aesthetic appearance. Fluid-filled bag 27 may
be painted after it has been formed in first mold 30, e.g., spray
painted. The desired color may be added by screen printing,
sublimation or any other desired method. In other embodiments,
pigment may be added to material 54, which is used to form
fluid-filled bag 27, in order to provide a desired color. Other
methods of imparting color to fluid-filled bag 27 will become
readily apparent to those skilled in the art, given the benefit of
this disclosure. It is to be appreciated that fluid-filled bag 27
may be painted a single color, or any combination of desired
colors, and in any desired pattern to produce a desired aesthetic
appearance.
[0038] A second mold 80, seen in FIG. 5, is used with fluid-filled
bag 27 to form support assembly 26. Second mold 80 has a first
portion 82 having a recess 84 formed therein. A first channel 86
extends from a periphery of first portion 82 to recess 84. A second
portion 88 has a projection 90 formed thereon, with a second
channel 92 extending from a periphery of second portion 88 to
projection 90. First portion 82 has a plurality of pins 94 that are
received in corresponding apertures 96 formed in second portion 88
in order to register and align first portion 82 with second portion
88.
[0039] Fluid-filled bag 27 is placed in recess 84 of first portion
82. A cushioning material 98, seen in FIGS. 6-8, is then poured
into recess 84, covering fluid-filled bag 27. Cushioning material
98 covers the exterior of fluid-filled bag 27, as well as filling
first and second recesses 66, 72 and extending through apertures
78, thereby forming pillars 25, seen in FIGS. 6-8. Second portion
88 is then placed on first portion 82 such that first and second
channels 86, 92 are aligned with one another to define a channel
that receives needle 58 used to form fluid-filled bag 27, a portion
of projection 90 is received in recess 84, and cushioning material
98 expands and fills first and second recesses 66, 72 and recess
84. Pillars 25 may have visible a parting line 102, formed at the
junction of walls 68 and 74 of first recess 66 and second recess
72, respectively, during the molding process.
[0040] A strip 104 of cushioning material 98 about the periphery of
support assembly 26 and the periphery 106 of fluid-filled bag 27 is
then cut away, exposing support assembly 26, as seen in FIGS. 6-7.
Pillars 25 of support assembly 26 can be seen to extend between the
cushioning material 98 that extends over the upper portion 60 of
fluid-filled bag 27 and the cushioning material 98 that extends
beneath the lower portion 62 of fluid-filled bag 27. Pillars 25, as
seen in FIG. 8, are formed of an outer layer 108, which comprises
walls 68, 74 of first and second recesses 66, 72, respectively of
fluid-filled bag 27, and an inner layer 110 of cushioning material
98. Cushioning material 98 and, naturally, pillars 25, serve to act
as a portion of midsole 22 of footwear 10.
[0041] In certain embodiments, cushioning material 98 is poured
polyurethane. It is to be appreciated that other materials that
will enhance the cushioning effect of support assembly 26 can be
used for cushioning material 98, such as ethyl vinyl acetate (EVA).
Other suitable materials for cushioning material 98 will become
readily apparent to those skilled in the art, given the benefit of
this disclosure. In certain embodiments, cushioning material 98
could be pre-formed and merely inserted into first and second
recesses 66, 72 and around fluid-filled bag 27.
[0042] As seen in FIG. 8, pillars 25 may taper inwardly from their
top toward a midpoint thereof, at parting line 102, and inwardly
from a bottom thereof to the midpoint at parting line 102.
[0043] It is to be appreciated that cushioning material 98 may also
be colored, and that different portions of cushioning material 98
may have different colors, thereby allowing one or more pillars 25
to have a first color with one or more other pillars 25 having a
second different color. It is to be appreciated that any number of
different colors can be used on pillars 25. Certain portions of
pillars 25 may have one color with other portions having different
colors. Thus, outer layer 108 and inner layer 110 of pillars 25 can
have any desired color combination to provide a desired aesthetic
design.
[0044] In addition, cushioning material 98 may not be uniform
throughout support assembly 26, that is, a first cushioning
material 98 having a first set of characteristics (density,
compressibility, stiffness, etc.) could be initially poured into a
first portion of second mold 80 and a second cushioning material 98
that is different than the first (that is, it has a set of
characteristics different than that of the first cushioning
material) could be poured into a second portion of second mold 80.
It is to be appreciated that any number of different cushioning
materials can be provided throughout support assembly 26.
[0045] In another embodiment, as seen in FIG. 9, inserts 112 may be
positioned within fluid-filled bag 27. As seen in this embodiment,
inserts 112 are positioned in first and second recesses 66, 72 and
include a central aperture 114 extending therethrough. Cushioning
material 98 passes through apertures 114 and fills the interior of
inserts 112, such that inserts 112 are positioned within cushioning
material 98 or inner layer 110. Inserts 112 act to provide
additional support for pillars 25. In certain embodiments, inserts
112 may be formed of a material having a greater stiffness or
rigidity than that of cushioning material 98. For example, inserts
112 may be formed of plastic.
[0046] It is to be appreciated that in certain embodiments, outer
layer 108 could be formed by injection molding material into a
desired shape. In such an embodiment, the injection molded material
is then placed into second mold 80 and cushioning material 98 is
poured into the mold, forming pillars 25.
[0047] It is to be appreciated that in certain embodiments, as
depicted in FIG. 10, fluid-filled bag 27 may have first recesses 66
formed on only one side thereof, with the other side of
fluid-filled bag 27 being substantially flat. Thus, cushioning
material 98 extends into each first recess 66 such that the walls
68 of first recess 66 and cushioning material 98 form outer layer
108 and inner layer 110, respectively, of pillars 25.
[0048] It is to be appreciated that in certain embodiments, as seen
in FIG. 10, fluid-filled bag 27 may include interior walls or
partitions 114 defining chambers 116. In such embodiments, only a
portion of periphery 106 of fluid-filled bag 27 may be cut away in
the manner described above, thereby leaving intact some chambers
116 of fluid-filled bag 27. Chambers 116 may be at ambient pressure
or inflated to a higher pressure. Chambers 116 can provide
additional support for support assembly 26.
[0049] By providing particular shapes, and sizes and locations of
first and second recesses 66, 72, the support provided by pillars
25 can be optimized. That is, the performance characteristics of
footwear 10 can be altered by positioning pillars 25 in desired
locations and by forming pillars 25 with desired shapes.
Accordingly, footwear 10 can be optimized for particular
activities, particular foot shapes or for any other reason.
Similarly, the amount and type of cushioning material 98 can be
varied throughout footwear 10 to optimize performance.
[0050] Similarly, by varying the thickness of the walls of
fluid-filled bag 27, the thickness of outer layers 108 can be
varied, thereby modifying the performance of pillars 25.
[0051] In light of the foregoing disclosure of the invention and
description of various embodiments, those skilled in this area of
technology will readily understand that various modifications and
adaptations can be made without departing from the scope and spirit
of the invention. All such modifications and adaptations are
intended to be covered by the following claims.
* * * * *