U.S. patent application number 12/606183 was filed with the patent office on 2010-11-04 for air circulating footbed and method thereof.
This patent application is currently assigned to BROWN SHOE COMPANY, INC.. Invention is credited to Daniel M. Doerer, Duane Shelton.
Application Number | 20100275468 12/606183 |
Document ID | / |
Family ID | 43029305 |
Filed Date | 2010-11-04 |
United States Patent
Application |
20100275468 |
Kind Code |
A1 |
Shelton; Duane ; et
al. |
November 4, 2010 |
AIR CIRCULATING FOOTBED AND METHOD THEREOF
Abstract
An air circulating footbed adapted for insertion into a shoe
including first and second layers of material shaped and attached
to each other so as to define at least two cavities therebetween,
the first cavity being disposed generally in the forefoot region of
a shoe and the second cavity being disposed generally in the heel
region of a shoe, the first and second cavities being in fluid
communication with each other whereby foot pressure exerted by a
wearer's foot in the forefoot and heel regions of the footbed
during a wearer's walking or running gait will circulate air flow
back and forth between the at least two cavities. The cavities may
also include low density polyurethane (PU) foam in the density
range of 0.20 to 0.50 pounds per cubic foot.
Inventors: |
Shelton; Duane; (Bourbon,
MO) ; Doerer; Daniel M.; (Town & Country,
MO) |
Correspondence
Address: |
HUSCH BLACKWELL LLP
190 Carondelet Plaza, Suite 600
ST. LOUIS
MO
63105
US
|
Assignee: |
BROWN SHOE COMPANY, INC.
St. Louis
MO
|
Family ID: |
43029305 |
Appl. No.: |
12/606183 |
Filed: |
October 26, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61173955 |
Apr 29, 2009 |
|
|
|
Current U.S.
Class: |
36/3B ; 36/28;
36/43 |
Current CPC
Class: |
A43B 13/386 20130101;
A43B 17/14 20130101; A43B 7/1445 20130101; A43B 17/03 20130101;
A43B 17/006 20130101; A43B 7/144 20130101; A43B 7/141 20130101 |
Class at
Publication: |
36/3.B ; 36/28;
36/43 |
International
Class: |
A43B 7/06 20060101
A43B007/06; A43B 13/18 20060101 A43B013/18; A43B 13/38 20060101
A43B013/38 |
Claims
1. A footbed adapted to be removably inserted into a shoe
comprising: a first layer having an upper surface and a lower
surface; a second layer having an upper surface and a lower
surface, said second layer being attached to said first layer so as
to define a sealed air circulating area therebetween; said air
circulating area including: a first cavity disposed at a location
corresponding to a location where a forefoot of a wearer's foot
would sit on said footbed; a first low density foam insert disposed
within the first cavity; a second cavity disposed at a location
corresponding to a location where a heel of a wearer's foot would
sit on said footbed; a second low density foam insert disposed
within the second cavity; and said second cavity being in fluid
communication with said first cavity for allowing air to circulate
between said first and second cavities.
2. The footbed of claim 1 wherein said air circulating area
comprises an interconnecting air transfer channel disposed between
said first and second cavities for allowing air to communicate
between said first cavity and second cavity.
3. The footbed of claim 2 wherein the interconnecting air transfer
channel has a height in the range of about 3-5 mm.
4. The footbed of claim 1 wherein each of said first and second
cavities has a height in the range of about 5-8 mm.
5. The footbed of claim 1 wherein said first and second low density
foam inserts comprise a polyurethane (PU) foam with a density
between 0.20 and 0.50 pounds per cubic foot.
6. The footbed of claim 1 wherein at least one of said first and
second cavities is sealed in fluid-proof manner by a heat sealing
method.
7. The footbed of claim 1 wherein said first and second cavities
are substantially filled with said first and second low density
foam inserts.
8. The footbed of claim 1 wherein the volume of said first low
density foam insert is less than the volume of said first
cavity.
9. The footbed of claim 1 wherein the second layer is formed of
ethyl vinyl acetate (EVA).
10. A footbed adapted to be removably inserted into a shoe, said
footbed having a forefoot region and a heel region, said footbed
comprising: a first layer having an upper surface and a lower
surface, said lower surface defining at least two concave surfaces
formed therein; a second layer having an upper surface and a lower
surface, said second layer being attached to said first layer so as
to define at least two cavities therebetween, wherein a low density
foam insert is disposed within each of said at least two cavities;
said first cavity being disposed at a location corresponding
generally to the forefoot region and being defined by one of said
concave surfaces and the upper surface of said second layer; said
second cavity being disposed at a location corresponding generally
to the heel region and being defined by one of said concave
surfaces and the upper surface of said second layer; and an
interconnecting channel disposed between said first and second
cavities for allowing air to communicate between said first cavity
and second cavity; whereby foot pressure exerted on the forefoot
region and the heel region of the footbed will circulate air
between said first and second cavities through said interconnecting
channel.
11. The footbed of claim 10 including a plurality of cavities and a
plurality of interconnecting channels disposed between said first
and second layers.
12. The footbed of claim 10 wherein the interconnecting air
transfer channel has a height in the range of about 3-5 mm.
13. The footbed of claim 10 wherein each of said first and second
cavities has a height in the range of about 5-8 mm.
14. The footbed of claim 10 wherein said first and second low
density foam inserts comprise a polyurethane (PU) foam with a
density between 0.20 and 0.50 pounds per cubic foot.
15. The footbed of claim 10 wherein at least one of said first and
second cavities is sealed in fluid-proof manner by a heat sealing
method.
16. The footbed of claim 10 wherein said first and second cavities
are substantially filled with said first and second low density
foam inserts.
17. The footbed of claim 10 wherein the volume of said first low
density foam insert is less than the volume of said first
cavity.
18. The footbed of claim 10 wherein the second layer is formed of
ethyl vinyl acetate (EVA).
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of and priority to U.S.
Provisional Patent Applications Ser. No. 61/173,955, filed Apr. 29,
2009, entitled AIR CIRCULATING FOOTBED AND METHOD THEREOF, which
application is hereby incorporated by reference to the extent
permitted by law.
BACKGROUND OF THE INVENTION
[0002] The present invention relates generally to the construction
of a shoe and the manufacture thereof and, more particularly, to a
footbed or sock lining with an improved air cushioning system to
enhance the comfort of a user's foot.
[0003] The footwear industry has seen numerous design features
introduced in order to enhance the comfort and/or performance of a
shoe on the foot of the wearer. Many of the technological advances
have occurred in the sole, particularly the midsole. In most
footwear, the midsole often provides both protective cushioning and
a stable platform for the user's foot. In an effort to provide
improved performance, it is often desirable to vary the support
characteristics of the sole from one region to another. A wide
variety of soles have been developed to provide variable support
over the foot. Although a marked improvement over conventional
uniform sole constructions has occurred over the years, there
remains a need for a footbed construction that can be adapted to
accommodate the mechanical stresses arising on a wearer's foot
during different kinds of activities and which provides a high
degree of functionality and wearing comfort.
[0004] A shoe is generally composed of an upper connected to a
sole. The sole is generally composed of an outsole, a midsole and
an insole disposed on top of the midsole. A footbed is disposed
within the shoe on top of the insole. The footbed lies adjacent to
the bottom surface of a user's foot when the shoe is worn. Because
the footbed is in direct contact with a user's foot, it is
important that the footbed be anatomically conformed to the user's
foot and help the foot remain cool and comfortable when inside the
shoe.
[0005] It has been known to provide a footwear sole to cushion the
impact of a person's foot with a supporting surface. The concept of
shock absorption by transfer of fluid from the heel to the ball or
forward portion of the user's foot has been known as illustrated in
U.S. Pat. No. 4,458,430 to Peterson. The Peterson patent describes
a cushioning device having cushions disposed beneath the heel and
front transverse arch of the foot. The cushions are filled with a
fluid. A major deficiency of the Peterson device is the "bulging
effect" when the Peterson device is made in the form of footbed or
sockliner. Particularly, the Paterson device leads to "bottoming
out" of heavily loaded chamber and the simultaneous ballooning of
unloaded chamber, creates a very uncomfortable bulge within the
unloaded chamber and causes discomfort of the foot portion
contacting the unloaded chamber due to the uneven surface of the
footbed or sockliner. Further, when one of the cushions is heavily
compressed, the foot portion contacting the compressed chamber
could feel some impact due to lack of threshold level of support as
fluid is forced from the compressed chamber to the expanding one.
Furthermore, extremely high level of quality control in some
manufacturing environment is needed to keep all the air cavities at
a consistent air pressure.
[0006] The demands for comfort in other athletic events has
resulted in the use of the inflatable bladders in various types of
athletic footwear. There are presently available athletic shoes
incorporating an air pump, such as depicted within U.S. Pat. No.
5,074,765, to inflate air bladders located within the sole of the
shoe, or alternatively, bladders located in portions of the midsole
or outsole of the athletic shoe. However, the prior art footwear
utilizing bladders have made them costly and time consuming to
manufacture.
[0007] It is a general object of this invention to provide an
improved shoe sole structure which avoids the drawbacks of the
known constructions. Still another object of the present invention
is to provide a shoe sole structure which is durable in
construction and inexpensive to manufacture, and which affords
additional advantages over the known shoe sole constructions. The
present devices attempt to enhance cushioning and energy return by
transferring a fluid between the area of impact and another area of
the device and to keep the threshold level of support by adding low
density foam insert to air cavities. The basic concept of the
present devices is to have cushions containing foam and air
disposed adjacent the heel or forefoot areas of a shoe which
transfer air to the other of the heel or forefoot areas.
[0008] Thus, it would be desirable to provide an improved footbed
which is capable of providing damping and support for the foot.
[0009] It would also be desirable to provide a footbed for a shoe
which is capable of circulating cushioning air through the interior
of the shoe.
SUMMARY OF THE INVENTION
[0010] The present invention relates to an improved footbed
including multiple cavities capable of holding air and foam, and an
interconnecting channel capable of circulating air between the
cavities. The term footbed refers to a layer of material or the
like placed over the entire insole to protect the foot from seams
or other constructional workings on the inside of the shoe. The
sole of a shoe is generally comprised of an outsole, a midsole, and
an insole. A conventional footbed may be placed inside the shoe
above the insole. The present invention is directed to a footbed
construction having enhanced air cushioning capability.
[0011] In one aspect of the present invention, an air circulating
footbed is provided which includes a multi-layered construction
enabling it to provide the above-described objectives. The footbed
includes two main layers and an air circulating system formed
therebetween. A top layer, sometimes called a sock liner, provides
a layer between the bottom surface of a wearer's foot and the
footbed. The top layer has an upper surface and a lower surface,
the top layer providing a sock-contacting surface as well as
protection for the footbed and an area to display the
manufacturer's information. Beneath the top layer, a bottom layer
of molded ethyl vinyl acetate (EVA) is attached. The bottom surface
of the top layer forms two concave surfaces, one located in the
area of the forefoot and the other located in the heel area. These
two concave surfaces, when positioned adjacent the bottom layer,
form two cavities enclosed by the top and bottom layers. The two
cavities are connected together by an interconnecting air transfer
channel located in the arch area, the interconnecting air channel
extending between the two cavities. The bottom layer extends from
the heel to the forefoot area, namely, in the area corresponding to
the ball of a wearer's foot. The front end portion of the bottom
layer is securely affixed to the lower surface of the top layer at
a location corresponding to the ball of the foot and the rear end
portion of the bottom layer is securely affixed to the lower
surface of the top layer in the vicinity of the heel area. The
method of attaching the top layer of the footbed to the bottom
layer of the footbed, thereby closing the cavities, can be by
adhesion or by heat sealing.
[0012] The air circulating system of the present invention includes
a front cavity, a rear cavity and an interconnecting air transfer
channel The interconnecting air transfer channel is designed to
optimize circulation of air between the two cavities. The front
cavity formed at the forefoot area is in direct air communication
with the rear cavity formed at the heel area through the
interconnecting air transfer channel formed at the arch area in the
middle section of the footbed. The flow of air from one cavity to
the other cavity is accomplished by pressure from the wearer's foot
during various parts of a wearer's walking or running gait.
[0013] The present cavities are at least partially filled with foam
and air function as a pumping and cushioning device. In one
embodiment, each cavity is substantially filled with suitable
low-density polymer foam insert, such as polyurethane, which is
resiliently compressible under an applied load to attenuate ground
reaction forces and absorb energy. In another embodiment, at least
one cavity is partially filled with suitable low-density polymer
foam insert. In a preferred embodiment, the foam insert is not
bonded to the inner surface of the cavities that hold some air
between the inner surface of the cavities and the outer surface of
the foam insert. Each of the front and rear cavities form a foam
holding volume which is vertically moved by the force or pressure
applied in the forefoot and heel areas of the top layer
respectively. When pressure is applied to the forefoot area during
toe-off, air moves rearward from the front cavity to the rear
cavity. When pressure is applied to the heel area during heel
strike, air moves forward from the rear cavity to the front cavity.
The cavities are formed in order to maximize the amount of air
trapped within such cavities and the amount of air pushed through
the interconnecting air transfer channel. Once the bottom layer is
affixed to the top layer, the air enclosed between the two layers
will be sealed such that no air enters the enclosed area and no air
can escape therefrom.
[0014] It is an object of the present invention to provide an
air-circulating footbed which provides enhanced cushioning by
adding ambient air as well as low density foam insert to the
cavities.
[0015] It is a further object of the present invention to provide
an improved footbed which is simple to manufacture and which can be
utilized in any standard shoe.
[0016] Specific advantages and features of the present system will
be apparent from the accompanying drawings and the description of
several illustrative embodiments of the present invention.
DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a top plan form view of one embodiment of a
footbed constructed in accordance with the teachings of the present
invention.
[0018] FIG. 2 is a side cross-sectional view of the footbed of FIG.
1 taken only line 2-2 of FIG. 1.
[0019] FIG. 3A is a fragmentary cross-sectional view of the present
footbed without showing foam insert within the cavities, taken
along line 3-3 of FIG. 1.
[0020] FIG. 3B is a fragmentary cross-sectional view of the present
footbed showing foam insert within the cavities, taken along line
3-3 of FIG. 1.
[0021] FIG. 4 is the side cross-sectional view of FIG. 2 showing a
user's foot positioned on the footbed.
[0022] It should be understood that the drawings are not
necessarily to scale and that the embodiments disclosed herein are
sometimes illustrated by fragmentary views. In certain instances,
details which are not necessary for an understanding of the present
invention or which render other details difficult to perceive may
have been omitted. It should also be understood that the invention
is not necessarily limited to the particular embodiments
illustrated herein. Like numbers utilized throughout the various
figures designate like or similar parts or structure.
DETAILED DESCRIPTION
[0023] Referring now to the drawings and, in particular, FIGS. 1-4,
a first embodiment of a new and improved removable shoe footbed
having an air circulating system embodying the principles and
concepts of the present invention and generally designated by the
reference numeral 10 will be described.
[0024] A shoe generally includes an upper and a sole assembly that
is affixed to the upper. The sole assembly includes an insole, a
midsole, and an outer sole, each having a peripheral shape designed
to conform to the shape of a wearer's foot. The shoe may also
include a footbed that is removably fitted into the shoe upper on
top of the sole assembly. To facilitate disclosure of the present
invention, reference will be made to various general areas of the
foot, such as the heel, arch and forefoot areas. When used to refer
to locations on the various sole components, these terms should be
interpreted to include those areas of the footbed that are disposed
generally (and not necessarily directly) beneath the corresponding
elements of the foot. It should be understood, however, that the
boundaries between the heel, arch and forefoot areas are not
precise and that these terms should be interpreted loosely and with
a great deal of flexibility.
[0025] A footbed 10, as shown generally in FIGS. 1 and 2, has a
medial side and a lateral side. Footbed 10 also has a toe end 12
and a heel end 14. The length and width of footbed 10 are
completely dependent upon the size of shoe into which footbed 10
will be placed. Footbed 10 is shown in FIGS. 2-4 to comprise two
main layers. A top layer 16, sometimes called a sock liner,
provides a layer between the wearer's foot and the footbed 10 and
may include multiple layers. Top layer 16 has an upper surface 18
and a lower surface 20. Upper surface 18 of the top layer 16 also
defines the upper surface of the footbed 10. The specific material
of the top layer 16 may be chosen depending on the nature and type
of shoe in which it will be used. Top layer 16 may be made from a
variety of materials including, but not limited to, grain leather,
suede leather, PVC coated materials, or any other thin synthetic or
natural material. The material selected will be determined by the
type of footwear into which footbed 10 is intended to be placed.
Top layer 16 is used to provide general protection to the footbed
10 from normal wear and tear. The height or thickness of the top
layer 16 may be raised at the arch and forefoot areas to support
the foot in a conforming fashion. Lying underneath top layer 16 and
providing a seal to circulating air is a bottom layer 22. The
footbed includes an air circulating system 24 between the top layer
16 and the bottom layer 22.
[0026] Referring now to FIGS. 2-4, the bottom layer 22 has an upper
surface and a lower surface. The upper surface of bottom layer 22
traps or encloses air within the air circulating system 24 formed
between the top and bottom layers 16 and 22. Bottom layer 22
extends from the heel area to the forefoot area as best seen in
FIGS. 2 and 4. In the embodiment illustrated, the bottom layer 22
extends from the heel area of footbed 10 to a location
corresponding to about two-thirds the length of footbed 10.
Although bottom layer 22 may extend to other portions of the
footbed, or the entire length of footbed 10, it is preferable that
bottom layer 22 extend only to the location corresponding to the
ball of the foot for increased forefoot flexibility. The front end
portion 26 of the bottom layer 22 is securely affixed to the lower
portion of the top layer 16 at a location corresponding generally
to the ball of the foot. The rear end portion 28 of the bottom
layer 22 is securely affixed to the lower portion of the top layer
16 generally at the heel area. The height or thickness of the
bottom layer 22 may be uniform across the entire length of the
bottom layer 22.
[0027] The air circulating system 24 includes a front cavity 30, a
rear cavity 32 and an interconnecting air transfer channel 34. The
material of the top layer 16 is molded by conventional molding
techniques, such as injection molding, to form two concave surfaces
19 and 21 in the forefoot and heel areas respectively, which
concave surfaces when enclosed by the bottom layer 22, form
cavities 30 and 32 as well as the interconnecting air transfer
channel 34 at the arch area between the two cavities. The top and
bottom layers 16 and 20, when mated and attached to each other,
form and define the front and rear cavities 30 and 32 respectively
and the interconnecting channel 34. The upper surface of bottom
layer 22 traps or encloses air within the air circulating system 24
formed between the top and bottom layers 16 and 22. In a preferred
embodiment, the cavities 30 and 32 are filled with suitable
low-density polymer foam insert 36 and 38, such as polyurethane,
which is resiliently compressible under an applied load to
attenuate ground reaction forces and absorb energy. Each of the
front and rear cavities form a foam holding volume which is
vertically moved by the force or pressure applied in the forefoot
and heel areas of the top layer respectively. The quantity of foam
insert 36 and 38 placed in the mold cavities is sufficient to
substantially fill the cavity when it is closed. During walking,
running, or other ambulatory activities, the cavity and the foam
insert therein are compressed between the foot and the ground,
thereby attenuating ground reaction forces and absorbing
energy.
[0028] While at least some portions of the cavities 30 and 32 are
filled with the foam insert 36 and 38, the remaining portion of
each cavity 30 and 32 will be filled with air. In one embodiment,
each cavity 30 and 32 is substantially filled with suitable
low-density polymer foam insert 36 and 38, such as polyurethane,
which is resiliently compressible under an applied load to
attenuate ground reaction forces and absorb energy. In another
embodiment, at least one cavity 30 and 32 is partially filled with
suitable low-density polymer foam insert 36 and 38. In a preferred
embodiment, the foam insert 36 and 38 is not bonded to the inner
surface of the cavities 30 and 32 that hold some air between the
inner surface of the cavities and the outer surface of the foam
insert 36 and 38. Further, the foam material is resiliently
compressible, in part, due to the inclusion of a plurality of open
or closed microcells that define an inner volume substantially
displaced by air. As the cavity 30 and 32 is compressed, the air
enclosed in the cavity 30 and 32 is transferred to the other cavity
through the interconnecting air transfer channel 34 such that the
partially or substantially filled cavities 30 and 32 enable excess
air to be squeezed out of the compressed cavity 30 and 32. Air
transfer channel 34 is designed to optimize circulation of air
between the two cavities 30 and 32. The front cavity 30 formed in
the vicinity of the forefoot area is in direct air communication
with the rear cavity 32 formed in the vicinity of the heel area
through the interconnecting air transfer channel 34 which is formed
in the vicinity of the arch area towards the middle section of the
footbed 10. The height or depth of the cavities 30 and 32 and the
air transfer channel 34 may vary depending upon the particular
application and the type of shoe involved. In a preferred
embodiment, the front and rear cavities 30, 32 may have a height in
the range of approximately 5-8 mm, while the interconnecting air
transfer channel 34 may have a height in the range of approximately
3-5 mm. The flow of air from one cavity to the other cavity is
accomplished by pressure from the wearer's foot during various
parts of a user's walking or running gait. Upon removal of the
compressive force caused by the foot and the ground, the original
configuration of the cavity is restored by the difference of the
air pressure between the cavities and recovery of the foam insert
to its original shape.
[0029] In order to fully appreciate the present invention,
implementation of the footbed 10 utilized in accordance with the
present invention will now be described. In use, footbed 10 is
placed inside a conventional shoe with bottom layer 22 pressed in
face-to-face contact with the insole of the shoe. As shown in FIGS.
2 and 4, when employing the cavities 30 and 32 as a pumping device,
the heel of the wearer's foot during heel strikes exerts or causes
sufficient pressure to be applied to the rear cavity 32 with
significant impact to force the air trapped within cavity 32 to
move forward through the transfer channel 34 to the front cavity
30. In similar fashion, the forefoot of a wearer's foot during
toe-off exerts or causes sufficient pressure to be applied to the
front cavity 30 with significant impact to force the air trapped
within cavity 30 to move rearward through the channel 34 to the
rear cavity 32. Each of the front and rear cavities 30 and 32 forms
an area which is vertically moved by the force or pressure applied
in the forefoot and heel areas of the footbed 10. The cavities are
formed by and between the top and bottom layers 16 and 22 of the
footbed 10 in order to maximize the amount of air trapped within
such cavities and the amount of air pushed through the
interconnecting air transfer channel 34. During the wearer's
walking or running gait, the increased pressure exerted by the ball
of the wearer's foot on the front cavity 30 will create sufficient
pressure to push air from the front cavity 30 to the rear cavity
32, and the increased pressure exerted by the heel of the user's
foot on the rear cavity 32 will create sufficient pressure to push
air from the rear cavity 32 to the front cavity 30 thus providing
the ball and heel of the wearer's foot with repeated blasts of air.
Once the bottom layer 22 is affixed to the top layer 16, the air
enclosed between the layers of the footbed 10 will be sealed and
trapped so that no air can enter or exit the enclosed area, namely,
cavities 30 and 32 and channel 34.
[0030] The precise composition of the bottom layer 22 is not
critical so long as it meets the physical and performance criteria
set out above. The top layer 16 may be comprised of a conventional
foam plastic material with a fabric sock liner integrally secured
to the upper surface of the top layer 16. The bottom layer 22 is
preferably made from a firm, compressible, lightweight, and
moldable material such as ethyl vinyl acetate (EVA). A number of
different polymers may be compounded and formed in a manner to meet
the necessary criteria but EVA is preferred. The density and
hardness of a suitable polymer foam insert may vary within the
scope of the present invention. In a preferred embodiment, the low
density foam insert is a polyurethane (PU) foam with a density
between 0.20 and 0.50 pounds per cubic foot.
[0031] The two layers 16 and 22 of the footbed 10 perform very
separate and distinct functions. The bottom layer 22 functions to
provide a conforming interface between the shoe and a wearer's
foot. Cushioning of the foot is provided primarily by the top layer
16 which functions as a pumping device for circulating air between
the cavities 30 and 32 and also acts to absorb lateral movements of
the foot relative to the shoe. The provision of the air circulating
system 24 within the footbed 10 prevents the top layer 16 from
bottoming out or reaching an uncompressible state.
[0032] The method of attaching the top layer of the footbed to the
bottom layer of the footbed, thereby closing the cavities, can be
by adhesion or by heat sealing. A surface roughing treatment which
can be formed by roughening the surface is often necessary prior to
application of an adhesive, or by high frequency, sonic or
conductive heat sealing. A suitable heat sealing apparatus applies
a current, whereby localised resistance heating causes the
thermoplastic materials to melt locally and to at least partially
fuse to join the thermoplastic materials. Preferably, the materials
become fused when they are cooled, to form a bond.
[0033] Although FIGS. 1-4 illustrate only a pair of cavities 30 and
32, it is also recognized and anticipated that the present footbed
10 could include any plurality of cavities interconnected by any
plurality of air transfer channels such as air channel 34. In this
regard, some or all of the cavities could be interconnected by the
transfer channels, or groups of the cavities could be
interconnected by certain air transfer channels. Further, although
FIGS. 1-4 illustrate only substantially filled or unfilled cavities
30 and 32, it is also recognized and anticipated that the present
footbed 10 could include a partially filled cavities. Other cavity
arrangements and interconnection schemes are also envisioned.
[0034] Thus, there has been shown and described several embodiments
of a novel invention. As is evident from the foregoing description,
certain aspects of the present invention are not limited by the
particular details of the examples illustrated herein, and it is
therefore contemplated that other modifications and applications,
or equivalents thereof, will occur to those skilled in the art. The
terms "having" and "including" and similar terms as used in the
foregoing specification are used in the sense of "optional" or "may
include" and not as "required". Many changes, modifications,
variations and other uses and applications of the present invention
will, however, become apparent to those skilled in the art after
considering this specification and the accompanying drawings. All
such changes, modifications, variations and other uses and
applications which do not depart from the spirit and scope of the
invention are deemed to be covered by the invention which is
limited only by the claims which follow.
* * * * *