U.S. patent application number 12/802874 was filed with the patent office on 2011-10-20 for dual-density eva footwear mid-sole and method for making same.
This patent application is currently assigned to Jimlar Corporation. Invention is credited to Justin R. Smith.
Application Number | 20110252670 12/802874 |
Document ID | / |
Family ID | 44787011 |
Filed Date | 2011-10-20 |
United States Patent
Application |
20110252670 |
Kind Code |
A1 |
Smith; Justin R. |
October 20, 2011 |
Dual-density EVA footwear mid-sole and method for making same
Abstract
The method for fabricating a dual-density mid-sole includes the
steps of: injection molding EVA material of a first density into a
block; placing the first density EVA block and raw EVA material
pellets of a second density together in a mold cavity; and applying
heat and pressure to the first density EVA block and raw EVA
material pellets of a second density in the mold cavity to form a
fused component. The fused component is shaped and detailed into
the mid-sole in a separate mold cavity. The result is a
dual-density mid-sole consisting of one or more blocks of EVA
material of a first density fused to EVA material of a second
density where the size, shape and location of the different density
sections can be accurately controlled and precisely defined. An
article of footwear including an upper, the dual-density mid-sole
consisting of one or more blocks of EVA material of a first density
fused to EVA material of a second density, and an outsole, may be
formed.
Inventors: |
Smith; Justin R.; (New York,
NY) |
Assignee: |
Jimlar Corporation
|
Family ID: |
44787011 |
Appl. No.: |
12/802874 |
Filed: |
June 15, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61342452 |
Apr 14, 2010 |
|
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Current U.S.
Class: |
36/25R ;
12/146B |
Current CPC
Class: |
A43B 13/125 20130101;
A43B 13/188 20130101; A43B 13/023 20130101; B29D 35/142
20130101 |
Class at
Publication: |
36/25.R ;
12/146.B |
International
Class: |
A43B 13/14 20060101
A43B013/14; A43D 8/00 20060101 A43D008/00 |
Claims
1. A method for fabricating a dual-density mid-sole comprising the
steps of: forming EVA material of a first density into a block;
placing the first density EVA block and raw EVA material of a
second density together; and applying heat and pressure to the
first density EVA block and raw EVA material of a second density to
form a fused component.
2. The method of claim 1 wherein the raw EVA material of a second
density is in the form of pellets when placed together with the
first density EVA block.
3. The method of claim 1 wherein the step of forming a block
comprises injection molding EVA material of a first density into a
block.
4. The method of claim 1 further comprising the step of trimming
the block.
5. The method of claim 1 further comprising the step of shaping the
fused component into the mid-sole.
6. The method of claim 1 further comprising the step of creating
design details on the exterior surface of the fused component.
7. The method of claim 6 further comprising the step of shaping the
fused component into the mid-sole.
8. The method of claim 7 wherein the step of shaping and the step
of detailing are combined into a single step.
9. The method of claim 7 wherein the step of shaping and the step
of detailing comprise the steps of placing the fused component in a
mold cavity and applying heat and pressure to the fused
component.
10. The method of claim 1 wherein the first density EVA material
has a lower density than the second density EVA material.
11. The method of claim 1 wherein the raw EVA material of a second
density has a higher density than the first density EVA
material.
12. The method of claim 1 further comprising the step of measuring
the amount of EVA material of a second density placed together with
the first density EVA block.
13. The method of claim 12 wherein the step of measuring comprises
the step of measuring the amount of raw EVA material of a second
density placed in the mold cavity with the bock as a function of
the volume of the block.
14. The method of claim 1 wherein the step of placing the first
density EVA block and the raw EVA material of a second density
together comprises the step of placing the first density EVA block
in a mold cavity and pouring the raw EVA material of a second
density into the mold cavity.
15. The method of claim 14 wherein the step of applying heat and
pressure to the block and raw material comprises the step of
applying heat and pressure to the block and raw material in the
mold cavity.
16. The method of claim 1 further comprising the step of
introducing a second first density block prior to applying heat and
pressure to fuse the component.
17. A method for fabricating a dual-density mid-sole comprising the
steps of: injection molding EVA material of a first density into a
block; placing the first density EVA block and raw EVA material
pellets of a second density together in a cavity; and applying heat
and pressure to the first density EVA block and raw EVA material
pellets of a second density in the cavity to form a fused
component.
18. The method of claim 17 further comprising the step of shaping
the fused component into the mid-sole.
19. A dual-density mid-sole comprising a block of EVA material of a
first density fused to EVA material of a second density.
20. The mid-sole of claim 19 wherein the EVA block is formed
separately, before the EVA block and EVA material are fused
together.
21. A dual-density mid-sole comprising first and second blocks of
EVA material of a first density fused to EVA material of a second
density.
22. The mid-sole of claim 21 wherein the blocks are formed by
injection molding, before the EVA material and blocks are fused
together.
23. An article of footwear comprising an upper, a dual-density
mid-sole comprising a block of EVA material of a first density
fused to EVA material of a second density, and an outsole.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to footwear and to a method
for making footwear and more particularly to a dual-density EVA
footwear mid-sole and a method for making same.
[0003] 2. Description of Prior Art Including Information Disclosed
under 37 Cfr 1.97 and 1.98
[0004] Footwear mid-soles fabricated from ethylene-vinyl acetate
(EVA) material are known in the art. Methods of fabricating EVA
mid-soles are also known. Such methods normally include heating and
applying pressure to raw EVA material in a mold cavity to fuse the
material into the desired shape. After the component is removed
from the mold and cured, it is shaped further and the exterior is
detailed. The mid-sole is then incorporated into the footwear
product using conventional fabrication techniques.
[0005] Fabrication of the EVA mid-sole in this fashion results in a
mid-sole with a substantially uniform hardness throughout. However,
for certain applications, it has been found to be desirable to have
an EVA mid-sole that is less hard in some areas, such as the
forefoot, and harder in other areas, such as the heel.
[0006] The conventional method to provide an EVA mid-sole with
areas of different hardness is to introduce the two different
density raw EVA materials into different locations within the mold
cavity and then fuse the different density raw EVA materials
together to form the mid-sole in a single step by applying heat and
pressure.
[0007] For example, raw EVA material of a first (relatively low)
density is used in sections of the mid-sole where less hardness is
desired and a raw EVA material of second (relatively high) density
is used in the sections where greater hardness is required. Each of
the different density raw EVA materials is introduced in a mold
cavity in the form of pellets that are poured into the respective
desired locations in the mold cavity. Heat and pressure is applied
to the different density raw EVA materials in the mold cavity. This
causes the pellets to fuse and form the mid-sole in a single
molding step.
[0008] While this single step molding process results in a mid-sole
with sections of different hardness due to the different densities
of the raw EVA materials, the boundaries of the different density
sections are not well defined and are difficult to control. This is
because the different density raw EVA pellets tend to mix together
to some extent as they are poured into the mold cavity. The result
is that the different density sections tend to run into each other.
Further, the different density sections are not uniform in size and
shape from one mid-sole to another.
[0009] It is therefore a prime object of the present invention to
provide a method of fabricating dual-density EVA footwear mid-soles
with well defined, stable different density sections.
[0010] It is another object of the present invention to provide
method of fabricating dual-density EVA footwear mid-soles with
different density sections of the desired size and shape.
[0011] It is another object of the present invention to provide a
method of fabricating dual-density EVA footwear mid-soles in which
the size, shape and location of the different density sections can
be accurately controlled.
[0012] It is another object of the present invention to provide a
method of fabricating dual-density EVA footwear mid-soles which are
uniform in structure.
[0013] It is another object of the present invention to provide a
method of fabricating dual-density EVA footwear mid-soles using a
two-step process where each mid-sole has harder and less hard
sections of precisely the desired shape, size and location.
[0014] It is another object of the present invention to provide a
method for fabricating a footwear mid-sole wherein one or more
blocks of EVA material of a first density are formed by injection
molding and thereafter the blocks are fused with EVA material of a
second density in a separate mold cavity by application of heat and
pressure to form the mid-sole.
[0015] It is another object of the present invention to provide a
dual-density mid-sole including one or more blocks of EVA material
of a first density fused to EVA material of a second density.
[0016] It is another object of the present invention to provide n
article of footwear including an upper, a dual-density mid-sole
comprising one or more blocks of EVA material of a first density
fused to EVA material of a second density, and an outsole.
BRIEF SUMMARY OF THE INVENTION
[0017] In general, the above objects are achieved by the present
invention which includes a method for fabricating a dual-density
mid-sole including the steps of: forming EVA material of a first
density into a block; placing the first density EVA block and raw
EVA material of a second density together; and applying heat and
pressure to the block and raw EVA material to form a fused
component of dual-density EVA.
[0018] Preferably, the raw EVA material of a second density is in
the form of pellets when placed together with the first density EVA
block.
[0019] The step of forming a block of the first density EVA
material includes injection molding EVA material of a first density
into a block. The block is then trimmed to the desired shape.
[0020] The method further includes the step of shaping the fused
component into the mid-sole. Thereafter, design details on the
exterior surface of the component are created. The steps of shaping
and detailing the component may be combined into a single step.
[0021] The step of shaping and the step of detailing include the
steps of placing the component in a mold cavity and applying heat
and pressure to the component.
[0022] Preferably, the first density EVA material has a lower
density than the second density EVA material.
[0023] The raw EVA material of a second density is preferably in
the form of pellets.
[0024] The method further includes the step of measuring the amount
of EVA material of a second density placed together with the first
density EVA block. This may be achieved by measuring the amount of
raw EVA material of a second density placed in the mold cavity with
the bock as a function of the volume of the block.
[0025] The step of placing the first density EVA block and the raw
EVA material of a second density together includes placing the
first density EVA block in a mold cavity and pouring the raw EVA
material of a second density into the mold cavity.
[0026] The step of applying heat and pressure to the block and raw
material includes applying heat and pressure to the block and raw
material in the mold cavity.
[0027] In accordance with another aspect of the present invention,
a method is provided for fabricating a dual-density mid-sole
comprising the steps of: injection molding EVA material of a first
density into a block; placing the first density EVA block and raw
EVA material pellets of a second density together in a cavity; and
applying heat and pressure to the first density EVA block and raw
EVA material pellets of a second density in the cavity to form a
fused component.
[0028] The method further includes the step of shaping the fused
component into the mid-sole.
[0029] In accordance with another aspect of the present invention,
a dual-density mid-sole is provided including a block of EVA
material of a first density fused to EVA material of a second
density.
[0030] The EVA block is formed separately, before the EVA block and
EVA material are fused together.
[0031] In accordance with another aspect of the present invention,
a dual-density mid-sole is provided including first and second
blocks of EVA material of a first density fused to EVA material of
a second density.
[0032] The blocks are formed by injection molding, before the EVA
material and blocks are fused together.
[0033] In accordance with another aspect of the present invention,
an article of footwear is provided including an upper, a
dual-density mid-sole comprising a block of EVA material of a first
density fused to EVA material of a second density, and an
outsole.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF DRAWINGS
[0034] To these and to such other objects that may hereinafter
appears, the present invention relates to a dual-density EVA
footwear mid-sole and a method for making same as described in
detail in the following specification and recited in the annexed
claims, taken together with the accompanying drawings, in which
like numerals refer to like parts and in which:
[0035] FIG. 1 is a perspective with of a footwear product with the
dual-density mid-sole of the present invention;
[0036] FIG. 2 is a side elevation view of the footwear product of
FIG. 1;
[0037] FIG. 3 is an exploded view of the footwear product of FIG. 1
showing the components thereof;
[0038] FIG. 4 is a cross-sectional view taken along line 4-4 of
FIG. 3 showing an idealized view of the interior of the
mid-sole;
[0039] FIG. 5 is a cross-sectional view take along line 5-5 of FIG.
4 showing an idealized view of the interior of the mid-sole;
[0040] FIG. 6 is an elevation view of the assembly of injection
molded EVA blocks;
[0041] FIG. 7 is a perspective view of an EVA block of a first size
and shape;
[0042] FIG. 8 is a perspective view of a an EVA block of a second
size and shape;
[0043] FIG. 9 is a perspective view of a mold cavity showing the
placement of two EVA blocks therein;
[0044] FIG. 10 is a perspective view of the mold cavity of FIG. 9
showing the measured amount of raw EVA pellets being introduced
into the cavity after placement of the EVA blocks;
[0045] FIG. 11 is a perspective view of the mold cavity after the
EVA pellets have been introduced and before the application of heat
and pressure;
[0046] FIG. 12 is perspective view of the mold cavity and contents
as heat and pressure are being applied to fuse the EVA, including a
cut-out portion showing the EVA material;
[0047] FIG. 13 is a perspective view of the fused EVA component as
it is removed from the mold;
[0048] FIG. 14 is a perspective view of the fused EVA component
shaping and detailing mold; and
[0049] FIG. 15 is a perspective view of the completed dual-density
EVA mid-sole.
DETAILED DESCRIPTION OF THE INVENTION
[0050] FIGS. 1 and 2 illustrate a typical footwear product,
generally designated A, incorporating the dual-density EVA mid-sole
of the present invention, generally designated B. The mid-sole B of
the present invention can be formed in whatever shape and size that
may be appropriate for footwear product A and with whatever
exterior contours and surface features desired. Accordingly, the
particular mid-sole design and footwear product style shown in the
drawings should not be considered in any way as a limitation on the
scope of the present invention but instead simply as a means of
illustrating a typical mid-sole B resulting from the fabrication
process of the present invention and a typical footwear product A
that might incorporate such a mid-sole.
[0051] FIG. 3 shows the components of footwear product A in
exploded form. Product A consists of an upper 10, an insole 12,
mid-sole B and an outsole 14. Upper 10, insole 12 and outsole 14
are all standard components manufactured by any one of a number of
well known fabrication methods and assembled with mid-sole B to
form product A using conventional techniques.
[0052] In order to achieve the dual density mid-sole B of the
present invention, as illustrated in the figures, a two step
process is employed. First, the blocks 16, 18 of one density EVA
material are forming by injection molding. The EVA material from
which the blocks 16, 18 are formed is selected for example to form
blocks that will be softer and more resilient than the EVA material
that will eventually form the remainder of the mid-sole.
[0053] The term "block" as used herein is meant to be broadly
construed to include any mass of material (such as the relatively
low density EVA as described in the preferred embodiment) having
definite, well-defined boundaries which is formed (for example by
injection molding) prior to and separately from the molding process
that fuses the block with a material of different density (such as
the higher density EVA pellets of the preferred embodiment) to form
a component.
[0054] FIG. 6 illustrates the assembly of blocks 16, 18 after it
has cooled and has been removed from the injection molding machine.
Blocks 16, 18 are still connected together by the plastic stem 20
produced by the channels in the injection mold through which the
molten EVA flows.
[0055] After blocks 16, 18 are severed from stem 20 and trimmed as
needed; they appear as seen in FIGS. 7 and 8. Two different size
and shaped blocks 16, 18 are shown to illustrate that the blocks
may be of any appropriated size and shape. Further, more than one
block may be incorporated into a single mid-sole, as shown in FIG.
9.
[0056] As seen in FIG. 9, one or more of the soft EVA blocks 16, 18
are placed in the mold cavity 22 of a forming/pressing machine 24.
The blocks can be positioned at any location within the cavity. As
shown in FIG. 10, after the soft blocks are placed in cavity 22, a
measured amount of raw EVA material pellets 26 is the poured into
the cavity. The mold cavity then appears as shown in FIG. 11.
[0057] The raw EVA pellets 26 introduced into the mold cavity are
of a different density than the EVA material used to form the
blocks. In this example, the EVA pellets 26 are made of less dense
EVA material than the EVA material from which blocks 16, 18 are
formed. Accordingly, the raw EVA pellets will form a harder, less
resilient end product than the blocks. The amount of pellets
introduced into the cavity is carefully measured in accordance with
the volume of the cavity, using a set formula, such that the fused
component, called a "cup" because of its shape, will be
approximately the size and shape of the desired mid-sole.
[0058] As illustrated in FIG. 12, after the mold is closed, heat
and pressure is applied to fuse the EVA pellets 26 and the blocks
16, 18 into a single component or cup 28, see FIG. 13. Cup 28 is
roughly the size and shape of the mid-sole but requires some
finishing. The cup is then shaped and detailed in a second
forming/pressing step which is performed in a different mold 30 to
complete the dual-density mid-sole of the present invention,
illustrated in FIG. 15.
[0059] FIGS. 4 and 5 are idealized illustrations of the internal
structure of the mid-sole of the present invention. FIG. 4 is a
longitudinal cross-section of the mid-sole showing the locations of
blocks 16 and 18 within the mid-sole. FIG. 5 is a lateral
cross-section take through the front portion of the mid-sole
showing block 18.
[0060] These figures show that the blocks 16, 18, made of the
softer, less dense EVA material, are precisely located within the
mid-sole and substantially maintain their original shape and size
through the fusing process. The blocks are completely surrounded by
the harder EVA material formed from the more dense raw EVA pellets.
The result is more cushioning for the foot in areas where the
softer blocks are located and more support for the foot in the
areas where the harder EVA is located.
[0061] Although somewhat idealized because some melting of the
exterior of the blocks may occur, FIGS. 4 and 5 show that the
boundaries between the different density EVA materials in the fused
component are much more well defined than would be possible in a
single step molding process where raw EVA pellets of both densities
are poured into different areas of a mold cavity and melted
together.
[0062] It will now be appreciated that using the fabrication method
of the present invention, the contours of two different densities
of EVA material in the mid-sole will match perfectly and the
location of each of the different density EVA materials within the
mid-sole can be accurately controlled to form a stable fused
component with softer and harder sections of size, shape and
location precisely as desired.
[0063] While only a single preferred embodiment of the present
invention has been disclosed for purposes of illustration, it is
obvious that many modifications and variations could be made
thereto. It is intended to cover all of those modifications and
variations which fall within the scope of the present invention, as
defined by the following claims.
* * * * *