U.S. patent application number 14/725775 was filed with the patent office on 2015-12-03 for thermoforming footwear method.
The applicant listed for this patent is Skysole Corporation. Invention is credited to Jerome Gross, Joseph Skaja.
Application Number | 20150342296 14/725775 |
Document ID | / |
Family ID | 54699903 |
Filed Date | 2015-12-03 |
United States Patent
Application |
20150342296 |
Kind Code |
A1 |
Skaja; Joseph ; et
al. |
December 3, 2015 |
THERMOFORMING FOOTWEAR METHOD
Abstract
An article of footwear and method of manufacturing an article of
footwear comprises an upper, a sole structure adjacent the upper
and a thermoplastic material sheet attached to the upper to fixedly
secure one or more components to the upper or fixedly secure the
upper to a sole structure where the thermoplastic material sheet
provides the primary or only means for securing the components to
the upper and the upper to the sole structure.
Inventors: |
Skaja; Joseph; (Hermosa
Beach, CA) ; Gross; Jerome; (Hermosa Beach,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Skysole Corporation |
Hermosa Beach |
CA |
US |
|
|
Family ID: |
54699903 |
Appl. No.: |
14/725775 |
Filed: |
May 29, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62005494 |
May 30, 2014 |
|
|
|
Current U.S.
Class: |
36/83 ; 12/142T;
12/146C |
Current CPC
Class: |
A43B 23/026 20130101;
A43B 9/12 20130101; A43B 23/0255 20130101; A43D 25/07 20130101;
B29D 35/06 20130101 |
International
Class: |
A43B 9/12 20060101
A43B009/12 |
Claims
1. An article of footwear comprising: an upper; a sole structure
adjacent said upper; and a thermoplastic material sheet attached to
said upper and said sole structure to fixedly attach said upper to
said sole structure, wherein said thermoplastic material sheet
provides the primary or only means for securing the upper to the
sole structure.
2. The article of footwear of claim 1, further comprising a
reinforcing mesh material juxtaposed with said thermoplastic
material sheet and positioned over a seam between said upper and
said sole structure.
3. The article of footwear of claim 1, wherein said sole structure
includes at least one of a midsole and an outsole.
4. The article of footwear of claim 1, wherein said sole structure
includes a bottom surface and said thermoplastic material sheet
extends onto at least a portion of said bottom surface of said sole
structure.
5. The article of footwear of claim 1, wherein said thermoplastic
material sheet comprises polyurethane.
6. The article of footwear of claim 1, wherein said thermoplastic
material sheet comprises at least one opening.
7. The article of footwear of claim 1, wherein said thermoplastic
material sheet comprises different thicknesses in different areas
of the upper.
8. A method of manufacturing footwear comprising: providing an
upper and a sole structure; heating a thermoplastic material sheet;
and applying said thermoplastic material sheet over said upper and
at least a portion of said sole structure to fixedly attach said
upper to said sole structure.
9. The method of claim 8, wherein said thermoplastic material sheet
comprises polyurethane.
10. The method of claim 8, further comprising inverting the upper
and the sole structure prior to applying said thermoplastic
material sheet over said upper and at least a portion of said sole
structure.
11. The method of claim 8, further comprising removably attaching
at least one cover plate onto the upper and the sole structure to
cover at least a portion of the upper and the sole structure to
enable at least a portion of the thermoplastic material sheet to be
cut away.
12. The method of claim 8, wherein said step of applying comprises
forming a partial vacuum with said upper to draw said thermoplastic
sheet to said upper.
13. A method of making at least a footwear upper comprising:
removably attaching a base material layer to a last; placing at
least one component on said base material layer; heating a
thermoplastic material sheet; applying said heated thermoplastic
material sheet to said base material layer and over said at least
one component, while said base material layer is attached to the
last to fixedly attach said at least one component to said base
material layer and form at least a portion of a footwear upper; and
removing said footwear upper portion from the last.
14. The method of claim 13, wherein said at least one component
includes an eyestay, a pre-formed collar, a tongue or a heel
support.
15. The method of claim 13, further comprising the step of placing
a sole structure on the last adjacent to said base material layer,
and wherein the step of applying said heated thermoplastic sheet
includes extending said thermoplastic material sheet onto at least
a portion of said sole structure to fixedly secure the sole
structure to said upper portion.
16. The method of claim 13, further comprising imprinting at least
one texture on said thermoplastic material sheet.
17. The method of claim 13, wherein the step of applying said
heated thermoplastic material sheet includes pressing said material
sheet over said base material layer and said at least one component
to fixedly attach said at least one component and said base
material together and conform said base material layer to a shape
of the last.
18. The method of claim 13, wherein said thermoplastic material
sheet includes polyurethane.
19. The method of claim 13, further comprising inverting the
last.
20. The method of claim 13, further comprising placing a plurality
of footwear components on the base material layer and attaching the
footwear components to the base material layer by applying said
heated thermoplastic material sheet over said base material layer
and said footwear components substantially without adhesive or
sewing.
21. The method of claim 13, further comprising drawing a partial
vacuum through an opening in said last using a vacuum generator to
draw said heated thermoplastic material sheet onto said base
material layer and over said at least one component.
22. A method of manufacturing footwear comprising: providing an
upper and a sole structure; heating a tape made of a thermoplastic
material; and pressing said tape over at least a portion of said
upper and at least a portion of said sole structure to fixedly
attach said upper to said sole structure.
23. An article of footwear comprising a collar with a flap that
overlaps an edge of an upper and an internal rib that accurately
indexes the collar to the last.
Description
PRIORITY CLAIM
[0001] This application is a non-provisional application of and
claims the benefit of U.S. Provisional Application No. 62/005,494
filed on May 30, 2014, which is incorporated herein in its
entirety.
BACKGROUND
[0002] Conventional methods of manufacturing footwear include
cutting fabric or other textile material to form uppers and then
stitching and/or gluing the uppers to a midsole or an outsole. The
footwear manufacturing steps are labor intensive, involve toxic or
environmentally harmful adhesives and solvents and require
expensive machinery. Thus, there is a need to simplify the
manufacturing process, reduce equipment and labor costs and reduce
or eliminate the use of toxic or environmentally harmful substances
in the manufacturing process.
SUMMARY
[0003] The present thermoformed shoe and thermoforming process
simplifies the manufacturing process by attaching one or more
footwear components or an upper to a sole structure solely or
primarily with a thermoplastic material sheet with minimal use of
(or reduced) adhesive, sewing or other attachment method.
[0004] In an embodiment, an article of footwear is provided and
comprises an upper, a sole structure adjacent the upper and a
thermoplastic material sheet attached to the upper to fixedly
secure one or more components to the upper or fixedly secure the
upper to a sole structure where the thermoplastic material sheet
provides the primary or only means for securing the components to
the upper and the upper to the sole structure.
[0005] In another embodiment, a method of manufacturing footwear
includes providing an upper and a sole structure, heating a
thermoplastic material sheet and pressing the thermoplastic
material sheet over the upper and at least a portion of the sole
structure to fixedly attach the upper to the sole structure.
[0006] In a further embodiment, a method of making at least a
footwear upper includes removably attaching a base material layer
to a last, placing at least one component on the base material
layer, heating a thermoplastic material sheet, applying the heated
thermoplastic material sheet to the base material layer and over
the at least one component, while the base material layer is
attached to the last to fixedly attach the at least one component
to the base material layer and form at least a portion of a
footwear upper and removing the footwear upper portion from the
last.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a perspective view of an embodiment of a shoe made
by the thermoforming process of the present invention.
[0008] FIG. 2 is a perspective view of an embodiment of a last of
the present invention.
[0009] FIG. 3 is a perspective view of an embodiment of an upper
formed by a base material placed on the last of FIG. 2.
[0010] FIG. 4 is a perspective view of the upper of FIG. 3
including a plurality of footwear components attached to the base
material.
[0011] FIG. 5 is a perspective view of an embodiment of a shoe of
the present invention made by attaching a midsole to the upper of
FIG. 4.
[0012] FIG. 6 is a perspective view of the shoe of FIG. 5 including
an outsole attached to the midsole.
[0013] FIG. 7 is a partial perspective view of an embodiment of a
thermoforming machine of the present invention.
[0014] FIG. 8 is a partial perspective view of the thermoforming
machine of FIG. 7 showing a heater positioned adjacent to the
thermoplastic polyurethane sheet.
[0015] FIG. 9 is a bottom plan view of an embodiment of a shoe mold
housing of the thermoforming machine of FIG. 7.
[0016] FIG. 10 is a side view of the shoe mold housing of FIG.
9.
[0017] FIG. 11 is a side view of the thermoforming machine of FIG.
7 showing the upper frame member moved toward the lower frame
member to thermoform an upper of a shoe.
[0018] FIG. 12 is a side view of a thermoformed upper of a shoe on
the lower frame member shown in FIG. 11 prior to trimming the
excess portions of the thermoplastic polyurethane sheet from the
upper.
[0019] FIG. 13 is a top view of an embodiment of a base material
layer including one or more materials laminated to the base
material layer.
[0020] FIG. 14 is perspective view of a shoe made by the
thermoforming process of the present invention where a pre-molded
collar is positioned about the foot opening and thermoformed to the
upper.
[0021] FIG. 15 are top and bottom views of an embodiment of the
pre-formed collar of FIG. 14.
[0022] FIG. 16 is a side view of an embodiment of a shoe mold
assembly of the thermoforming machine of FIG. 7 that includes two
liners.
[0023] FIG. 17 is a bottom view of the shoe mold assembly of FIG.
16.
[0024] FIG. 18 is a side view of an embodiment of a sole structure
for a shoe made by the thermoforming process of the present
invention where the sole structure includes a groove for guiding a
cutting tool during the trimming process.
[0025] FIG. 19 is a side view of another embodiment of a shoe mold
assembly of the thermoforming machine of FIG. 7 that includes an
inverted mold.
[0026] FIG. 20 is a side view of a further embodiment of the
present thermoforming machine where the upper is inverted prior to
the thermoforming process.
DETAILED DESCRIPTION
[0027] FIG. 1 shows an article of footwear, and more specifically,
a shoe, made by a thermoforming process described below. The
thermoforming process forms a footwear upper by thermoforming or
overmolding a piece of thermoplastic polyurethane (TPU) or other
moldable material over a base layer made of one or more pieces of
material for, i.e., for the forefoot, vamp, quarters and/or other
parts of the upper, and one or more footwear components.
Additionally, a sole or a sole structure may be attached to the
footwear upper during the thermoforming process. The sole structure
may include, but is not limited to, one or more of: a midsole, an
outsole, a unitary sole, a sole shell that is hollow and includes
one or more cushioning materials or elements, a cushioning material
layer or layers or any suitable material or materials. It should be
appreciated that the footwear upper may be an upper for a shoe,
boot, sandal or other article of footwear.
[0028] Referring to FIGS. 1-6, the shoe 10 includes an upper 12
having a base layer 14. Prior to thermoforming or overmolding the
upper, the base layer 14 is stretched or placed over a last or core
16 so that it mimics the shape of the last. To secure the base
layer 14 to the last 16, opposing bottom sides/edges 18 of the base
layer are interconnected by a lasting method such as strobel
lasting, i.e., stitching an insole to a bottom edge of the upper,
to initially form the upper 12. Alternatively, the upper 12 may be
formed by string lasting, i.e., the bottom edges of the upper are
connected by threading one or more strings through the bottom edges
in a straight or criss-crossing pattern, or connected by a lasting
board, a piece of material or other suitable connecting member.
Alternatively, the upper may be temporarily attached to the last 16
by using a multi-use adhesive, drawing a vacuum through the last,
using hook and loop materials, using magnets or other suitable
temporary attachment devices and methods. In this way, the
overmolding is performed on the upper 12 without having to use the
lasting procedure described above.
[0029] In an embodiment, the upper 12 may be formed by a tubular
knit material, such as a tubular fabric, where the last 16 is
inserted into the upper through an opening in the tubular material
such as the foot opening 20. For example, the base layer 14 may be
formed by knitting or weaving the base layer into a tube with a
closed end similar to how a sock is made. The tubular base layer or
sock may be formed with different thicknesses, stretch,
breathability and/or patterns in different areas of the base layer
to create specific functional zones. By altering the construction
in specific areas of the sock, a highly functional upper can be
made that also has an inner surface that is comfortable against a
wearer's foot. The sock can also be made with one or more
materials, and decorated and colored to complement the color and
texture of other materials used to form the upper. Further, forming
the upper as a sock helps eliminates material waste and simplifies
the manufacturing process by eliminating some of the extra
finishing steps needed for form the upper.
[0030] FIG. 2 shows a thermoforming mold, such as the last 16,
which is made of a durable material such as a solid thermoplastic
material, metal such as aluminum, wood, plastic, a composite
material or any suitable material. In the illustrated embodiment,
at least a portion of the last 16 includes shaped indentations,
recessed areas and holes that are used to form a pattern in the
base layer and/or components. In the example embodiment shown in
FIG. 2, the last 16 includes a plurality of circular recessed areas
22 and circular designs 24 formed by a plurality of recessed
openings or holes 26. It should be appreciated that the recessed
areas 22 and designs 24 may be any suitable shapes, symbols or
characters. In the illustrated embodiment, an interior 28 of the
last 16 is hollow or includes a hollow area for enabling at least a
partial vacuum to be drawn through a plurality of holes 24 and/or
26 in the last that extend from the outer surface 30 to the hollow
interior 28.
[0031] One or more material manipulating tools (not shown) may also
be associated with or attached to the last 16. For example, one or
more air tubes may be attached to an inner surface of the last such
that air is blown outwardly from one or more areas on the last to
manipulate the thickness of the TPU on the upper and/or sole
structure as it is being overmolded on the upper and/or the sole
structure. Another tool (not shown) may be used to fold at least a
portion of the TPU underneath the upper or the sole structure. It
should be appreciated that any suitable manipulating tool or tools
may be used to change the properties and/or location of the TPU on
the upper and the sole structure.
[0032] While the upper is on the last, one or more components 32
are temporarily attached to the base layer 14. The components 32
can be temporarily attached to or held on the base layer 14 by
using a multi-use adhesive, drawing a partial vacuum through the
last, using hook and loop materials, using magnets or other
suitable temporary attachment devices and methods. It should be
appreciated that a partial vacuum can be generated based on any
suitable vacuum generation method or process including using a
non-hollow last or mold. The overmolded thermoplastic layer then
conforms and holds the components 32 in place on the base layer 14
as described below. Various apertures 31 (FIG. 4) can be formed in
a given component or components 32 to expose the base layer so that
the thermoplastic layer further bonds the components to the base
layer 14 during the overmolding process. The apertures or openings
may also be formed in any material layer or layers on the base
layer 14 to enhance the bond between those layers. Also, the base
layer 14 may include one or more apertures 33 (FIG. 4) for
strengthening the bond between the base layer and one or more
internal shoe components such as an inner material liner,
cushioning materials, a heel counter or other components.
[0033] In the illustrated embodiment, the components 32 include an
eye stay 34 positioned about a central opening 36 in the upper, a
collar 38 for reinforcing an area around the foot opening 20 and a
heel support or heel foxing 40 for reinforcing and supporting the
heel 42. Additional components 44 are attached to opposing sides of
the upper 12 for structural support and/or aesthetic purposes. It
should be appreciated that one or more of the components 32 may
cover a portion or portions of the base layer 14 or the entire base
layer. It is also contemplated that the base layer 14 and one or
more of the components 32 may be the same material or different
materials. In the illustrated embodiment, the base layer 14 and/or
the components 32 may be ethylene vinyl acetate (EVA), rubber,
fabric, textile, foam or any suitable material or combination of
materials. Additionally, the base layer 14 may include openings,
vents and/or a mesh material to enhance the breathability and
comfort of the shoe.
[0034] Referring to FIGS. 14-15, in an embodiment, a collar 115 is
pre-formed or pre-molded as a single, component having an inner
portion 116 and an outer portion 118. The ends of the inner portion
116 and the outer portion 118 are integrally connected to form a
hinge 120 so that the inner and outer portions pivot relative to
each other. In the illustrated embodiment, the pre-formed collar
115 includes one or more holes that are temporarily held or secured
to the last 16 by one or more pins 117 extend from the last 16
(FIG. 2) and an internal rib that accurately indexes the collar to
the last. After securing the pre-formed collar 115 to the last, the
base layer 122 is moved upwardly between the inner and outer
portions 116, 118 so that the inner portion is positioned generally
adjacent to the inner surface of the upper 124 and the outer
portion or outer flap of the collar is positioned partially over
the outer surface 126 of the base layer 122 so that the outer
portion is visible on the outer surface of the shoe. It should be
appreciated that the pre-formed collar 115 may be secured to the
last using any suitable connection method. Alternatively, the
pre-formed collar 115 can initially be placed on the base layer 122
and then the combined base layer and collar are secured to the
last. Now, during the thermoforming process, the collar 115 is
thermoformed or overmolded on the base layer. Attaching the collar
and/or other components to the base layer in a single step as
described above, saves significant time and money over conventional
methods of attaching the collar to the upper, which include
stitching and/or gluing the collar to the upper after the upper was
made. It should be appreciated that the pre-formed collar 115 may
be made with a single material or a combination of materials and/or
may have the same thickness or areas with different thicknesses.
For example, the inner portion may be made with a thicker,
cushioning material or materials to provide extra support and
comfort to a wearer's foot. The material or materials used to make
the pre-formed collar may include fabric or any suitable materials
and may include one or more patterns and colors.
[0035] A tongue 46 is another component that can be attached to the
upper 12 during the thermoforming process by cutting a piece of
material in a desired shape and placing the piece of material on
the upper so that the piece of material at least partially overlaps
a portion of the base layer 14. To ensure that only a portion of
the tongue 46, namely the distal end 48 of the tongue, is attached
to the base layer 14, a shield or cover plate is placed over the
tongue so that only the portion of the tongue being attached to the
base layer is exposed and overmolded by TPU during the
thermoforming process. It is contemplated that other components 32
such as a toe cap, reinforcements and/or logos may also be
temporarily attached to the base layer 14.
[0036] FIG. 5 shows a sole structure 50, and more specifically, a
midsole 52 attached to the upper 12. The midsole 52 may be made of
EVA, R-MAT.TM. foam, foam, ethylvinyl acetate, rubber or another
suitable material or combination of materials. In this embodiment,
the upper 12 is positioned on, but not fixed to, the midsole 52. As
described below, the upper 12 is attached to the midsole 52 during
the thermoforming process. It should be appreciated that the
thermoforming process can be used to form the upper with or without
a sole structure.
[0037] FIG. 6 shows another part of the sole structure 50, namely
an outsole 54, attached to the midsole 52. In the illustrated
embodiment, the outsole 54 is made of rubber but may be made with
any suitable material or combination of materials. A bottom surface
56 of the outsole 54 includes a plurality of tread members 57 that
enable the outsole to grip an underlying surface such as the ground
or a floor. In an embodiment, the outsole 54 is attached to the
midsole 52 by adhesive, stitching or another suitable attachment
method. It is also contemplated that the outsole 54 can be attached
to the midsole 52 by the present thermoforming process or a
combination of these processes.
[0038] FIGS. 7-12 shows some of the parts of the machine that
performs the thermoforming or overmolding process for forming the
upper 12 and/or attaching a sole structure 50 to the upper.
[0039] More specifically, a thermoforming machine 58 includes a
frame 60 having a mold sub-base 61 and a lower frame member (mold
base A) 62 that is movably connected to the frame by one or a
plurality of mold base guides such as hydraulic or air cylinders 64
located generally at each corner of the lower frame member. A
support member or pedestal (mold base B) 66 is attached to a top
surface 68 of the lower frame member 62 and has a size and shape
that corresponds to a size and shape of an article or articles of
footwear for supporting the footwear during the thermoforming
process. In the illustrated embodiment, the midsole 52 is placed on
the pedestal 66 and then the upper 12 (including the last 16) is
placed on the midsole. Optionally, one or more pins or pegs may be
inserted through an inside surface of the upper 12 and midsole 52
and into the pedestal 66 to temporarily hold the upper and midsole
in place during the thermoforming process. The pins may also be
part of the pedestal 66 and extend outwardly such that when the
upper 12 and midsole 52 are placed on the pedestal, the pins
project through the midsole and upper to hold them in place. It
should be appreciated that the upper 12 and the sole structure 50
may also be joined together and then secured to the pedestal
66.
[0040] A clamping member 70 is attached to the frame 60 and is
initially positioned over the upper 12 and the sole structure,
i.e., midsole 52, on the pedestal 66. The clamping member 70
includes a pair of opposing rectangular clamping frames or brackets
72 each being the same general size and shape and each defining
openings 74. A sheet of TPU 76 or other formable material is
clamped between the brackets 72 to secure the TPU sheet in place.
Alternatively, the TPU sheet 76 may be taped to one or both of the
brackets 72 or secured to the brackets or another type of clamping
member using any suitable connection method. The TPU sheet 76 has a
designated thickness, hardness and other properties. Preferably,
the TPU sheet 76 has a hardness of 60 to 85 Shore A. For example in
the illustrated embodiment, the TPU sheet 76 is a 94 Shore A TPU
sheet, which is generally around 0.010 inches thick. It should be
appreciated that the thickness of the TPU sheet is selected
according to design criteria, but will generally range from 0.004
to 0.100 inches, depending on the particular material properties.
In an embodiment, the preferred thickness ranges from 0.060 to
0.080 inches but may be any suitable thickness. The TPU sheet 76
may also include one or more perforations, holes or openings.
Alternatively, the TPU sheet 76 may have a non-uniform thickness,
i.e., different thicknesses in different areas, and different
properties by using multiple material layers in different areas of
the TPU sheet. As an example, the TPU sheet 76 may be thicker along
the edge of the sole structure 50 to enhance the strength of the
TPU in this area. A composite layered sheet may also be used to
enhance strength. It should be appreciated that other types of
materials or combination of materials may be used other than
TPU.
[0041] As shown in FIG. 7, a shoe housing assembly including an
upper frame member 78 is positioned on an opposing side of the
clamping member 70 from the lower frame member 62. The upper frame
member 78 includes two, spaced platforms 80a and 80b joined
together by four support posts 82 each located at a corner of the
platforms. Further, a main hydraulic or air cylinder 84 attachment
member and one or more outer hydraulic or air cylinders, such as
four outer hydraulic cylinders 86 are attached to the top platform
80a to movably connect the upper frame member 78 to the frame 60.
As shown by the arrows in FIG. 7, the upper and lower frame members
78 and 62 each move toward and away from the clamping member 70
holding the TPU sheet 76.
[0042] A pressure box or shoe mold housing, such as mold member 88,
is attached to a bottom surface 90 of the lower platform 80b. The
mold member 88 has an interior hollow area 92 (FIG. 9) at least a
portion of which has a size and shape that corresponds to the size
and shape of the upper 12 and/or the sole structure 50. To help
form the vacuum within the mold member and prevent the TPU sheet 76
from sticking to or adhering to the mold member 88, a flexible,
silicone cover or liner 94 is secured to the mold member by
connectors 96 and is configured to cover a bottom surface 98 of the
mold member and form vacuum barrier. It should be appreciated that
silicone and other similar materials with significant elongation
properties may be used to make the liner 94 so that the liner
applies significant pressure on the upper 12 and the sole structure
50 during the thermoforming process. It should also be appreciated
that the liner 94 may be made with a suitable non-stick material or
any other suitable material or combination of materials. Also, foam
that is typically used to cushion and add comfort to the upper 12
can be replaced by installing cushioning structural elements such
as hemispheres in the mold member 88. These structural elements can
be of any size or shape and can be reinforced if necessary with
inserted materials. The overmolded TPU sheet 76 will readily copy
these shapes and mold any material that is in contact with it.
Additionally, the overmolded TPU sheet 76 can be shaped during
molding to provide stiffness and strength where desired. The liner
94 eliminates the need for matched compression tools and the
corresponding accuracy associated with such tools and thereby
significantly decreases costs associated with these tools. In
another embodiment, a second liner 128 (FIG. 16), preferably made
of a non-stick fabric, such as nylon, having maximum stretching
capabilities, is inserted between the TPU sheet and the liner 94 to
form or imprint the TPU with one or more textures. For example, the
texture could be a criss-crossing pattern or other suitable
patterns. The textures help to mask the plastic appearance or
plastic surface of the TPU sheet on the finished shoe surface.
Furthermore, textures are typically imprinted on an upper in a
separate machining step at a different location from the shoe
manufacturing location. By including texture or textures on the
second liner 128, the cost and time associated with imprinting such
texture(s) on the upper are significantly reduced. Alternatively,
the liner 94 may have one or more textures that are imprinted or
formed on the TPU sheet on the upper and/or sole structure during
the thermoforming process.
[0043] Alternatively, the mold member 88 can be made out of
silicone and thereby function without the liner 94. It should be
appreciated that the mold member 88 may be made with a non-stick
material or any other suitable material or combination of
materials. The mold member 88 can also include protrusions or
molded areas on its inner surface that apply pressure to certain
points or locations on the upper and/or sole structure for pressing
the TPU into recessed areas on the base layer or for forming
patterns, indentations, grooves or other formations on the base
layer and/or components.
[0044] Additionally, various materials can be attached to an inner
surface of the mold member 88 where the materials contact the upper
and the last as the TPU is making contact with the upper and the
last. This method stabilizes the upper and the last and securely
presses the sole structure and upper together so that there are no
gaps or spaces between the upper and the sole structure thereby
ensuring a tight connection between the upper and the sole
structure. The mold member 88 can also include various manipulative
robotic fixtures that can aid in the forming process.
[0045] A vacuum hose 100 is connected at one end to the lower frame
member 62 and at an opposing end to a vacuum generator, e.g., a
compressor or vacuum pump, located in or near the machine. Suitable
tubing or piping extends from the interior hollow area 28 of the
last 16 to the end of the vacuum hose connected to the lower frame
member 62. Alternatively, the vacuum hose 100 may extend through
the lower frame member 62 and connect directly to the bottom of the
last 16 and thereby the hollow interior 28 of the last. The vacuum
generator creates a designated partial vacuum level or amount of
suction in the vacuum hose 100 for drawing air through the interior
28 and holes 26 in the last 16.
[0046] On an opposing side, a pressure hose 102 is connected at one
end to the upper frame member 78 and at an opposing end to a
pressure generator located in or near the machine. The pressure
generator generates pressurized air at a designated pressure and
supplies the pressurized air to the pressure hose 102, which in
turn, directs the pressurized air into the mold member 88.
[0047] The thermoforming machine 58 also includes a heater 104 that
is movably connected to the frame 60 and moves transverse to the
movement of the upper and lower frame members 78 and 62. The heater
104 includes one or more heating elements 106 (FIG. 8), such as
ceramic electric heating elements or coils, that are heated to a
designated temperature. During the thermoforming process, the
heater 104 is initially positioned over the clamping member 70 such
that the heater moves between a first position in which the heater,
and more specifically, the heating elements 106 are positioned over
the TPU sheet 76, and a second position in which the heater 104 is
moved away from the clamping member and TPU sheet. It should be
appreciated that there are many different thermoforming machine
configurations such as turn table designs/systems, automatic
in-line systems and combinations of these systems. In this regard,
the heaters in these systems may include any suitable heater or
heaters such as an oven or ovens or one or more heating
elements.
[0048] In an example, the upper 12 (including last 16) and the sole
structure 50 (as shown in FIGS. 7 and 8) are placed on the pedestal
66 of the lower frame member 62. The heating elements 106 of the
heater 104 are energized to heat to a designated or pre-programmed
temperature. In the illustrated example, the TPU sheet 76 is heated
to a temperature of 340-400 degrees F. but may soften or melt at
significantly lower or higher temperatures. Other temperatures may
be used depending on the properties of the TPU sheet. At the same
time that the sheet 76 is being heated, the vacuum generator
generates a partial vacuum in the vacuum hose 100, the pedestal 66
and the interior 28 of the last 16. The heater 104 is initially in
the first position over the TPU sheet 76. As the heating elements
106 increase in temperature, the heat generated by the heating
elements heats or increases the temperature of the TPU sheet 76 to
a temperature approaching the melting point of the TPU. After
reaching a designated temperature of the TPU, the heater 104
retracts or moves away from the TPU sheet 76.
[0049] Next, the upper and lower frame members 78 and 62 are moved
together so that the upper 12 and sole structure 50 on the pedestal
66 are moved upwardly into the heated TPU sheet 76 and the upper
frame member 78 simultaneously moves downwardly so that the mold
member 88 moves into an opposing side of the TPU sheet until
contacting the upper surface 108 of the lower frame member 62. In
this position, the TPU sheet 76 is sealed off by contact of the
peripheral edge of the mold member 88 with the surface 68 of the
lower frame member 62 so that the upper 12 and sole structure 50
are enclosed between the mold member 88 and the lower frame member
62. The vacuum generated via vacuum hose 100 pulls and conforms the
TPU sheet 76 on the upper and the sole structure. Similarly, the
pressurized air from the pressure hose 102 pushes or presses the
cover/liner 94 and thereby the TPU sheet 76 downwardly onto the
upper 12 and the sole structure 50. Thus, in a single step, the TPU
sheet 76 encapsulates and permanently attaches the components 32
and the sole structure 50 to the base layer 14 of the upper. It
should be appreciated that the pressure hose 102 is optional and
the process can be performed solely using the vacuum drawn through
the last by the vacuum hose and vacuum generator.
[0050] Furthermore, heat from the TPU sheet 76, approximately a
temperature of 400 degrees F., is transferred to the various
components 32 when the upper 12 is overmolded with TPU sheet 76.
This collateral heat can be used to trigger hotmelt adhesives which
can be placed in between the components 32 and the base layer 14
and/or between the TPU sheet 76 and the base layer 14 to further
enhance the bonds between these parts of the shoe. The heat also
makes the various components pliable and molds them to the last
just as the TPU sheet 76 sets up and takes the shape of the last as
it is forced into position by vacuum and/or the pressurized
air.
[0051] After a designated period of time, the upper frame member 78
is moved away from the clamping member 70 to expose the
thermoformed upper and sole structure, which are now encapsulated
and bonded by the TPU sheet 76. The length of time that the heater
is over the TPU sheet depends the melting temperature and thickness
of the TPU sheet or other material, and the type of heater being
used such as for example, if a single or double oven is being used.
In the illustrated embodiment, the heater is positioned over and
heats the TPU sheet 76 between 1-60 seconds.
[0052] It should be noted that the bonding characteristics of the
TPU sheet 76 with the upper 12 and the sole structure 50 can be
enhanced. For example, in an embodiment, hotmelts are applied
directly to the TPU prior to forming, or a TPU powder is applied to
a portion of the upper 12 and/or the sole structure 50 to enhance
the bond between the TPU sheet 76, the upper 12 and/or the sole
structure 50. Further, a mesh material or other suitable material
may be placed over the seam between the upper 12 and the sole
structure 50 to strengthen the connection between the upper and
sole structure after the TPU sheet 76 has been thermoformed or
overmolded onto the upper and sole structure. It should be
appreciated that additional materials may be applied to the TPU
sheet, fabric or components to enhance bonding. Additionally,
fabrics forming the upper can be constructed with fibers having the
same chemical makeup as the TPU sheet 76. These fibers are
partially or completely coated with the overmolding material,
namely the TPU forming the TPU sheet, to ensure enhanced bonding to
the TPU sheet. Also by coating the fibers with the base material,
i.e., the TPU, the fabric can be molded without the TPU sheet.
[0053] Also, as described above, during the thermoforming process,
the TPU sheet 76 is conformed to the upper 12, the components 32
and the last 16 such that the material layer or layers of the upper
are pressed into the circular recessed areas 22 and designs 24 in
the outer surface of the last. This creates corresponding shapes in
the upper 12 that also project at least partially into the interior
of the upper. The inner projecting, shaped areas of the upper 12
help to maintain space between the inside surface of the upper 12
and a wearer's foot thereby creating spaces or pathways for air to
travel about the foot and keep the wearer's foot drier and
comfortable.
[0054] In the illustrated embodiment, a cutting tool is used to
manual cut the foot opening 20 and around a bottom edge 108 (FIG.
12) of the sole structure 50 to separate the upper and the sole
structure from the pedestal 66. The cutting tool is preferably a
heated blade or knife but may be any suitable cutting tool.
Alternatively, a trim plate or cover plate, or similar cutting
device shield is attached to the mold member 88 to help cut away
the excess portions of the TPU sheet 76 from the foot opening 20
and the bottom edge 108 of the sole structure as the upper frame
member 78 and mold member 88 move downwardly onto the upper 12 and
sole structure 50. In the latter embodiment, the thickness of the
liner 94 can be increased or increased only in the cutting areas to
help prevent damage to the liner during cutting of the excess TPU.
A cover plate or shield may also be used to cover the tongue 46
and/or other parts of the upper 12 to protect these areas from
being inadvertently cut or damaged during cutting. Alternatively,
several cover plates are shaped to conform and cover one or more
parts of the upper 12 to prevent inadvertent cutting of those parts
during the trimming or cutting process. The cover plates are made
of a durable material, such as a thermoplastic, that is strong
enough to prevent penetration and/or cutting of the material by the
cutting device. To further enhance the cutting of the excess TPU
material from the shoe, a heat reflective material is attached to
the cutting device adjacent to one or both sides of the cutting
device to help prevent inadvertent contact between the knife and
the upper, the midsole, the outsole or other portion of the shoe.
In an embodiment, the heat reflective material is a syntactic foam
that is heat resistant yet strong enough to withstand repeated
cutting operations. In an example embodiment, the cutting tool is
constructed similar to a pizza cutter with a round central blade
attached to handle. Round washers made of the heat reflective
material having a diameter that is smaller than the diameter of the
blade are mounted on each side of blade to protect the portions of
the shoe not being cut by the blade.
[0055] In another embodiment, the cover plate or trim plate is
secured to the upper 12 prior to initiating the thermoforming
process. The edge of the trim plate includes a groove in which a
heated knife or laser is inserted for trimming the TPU from the
thermoformed footwear. The trim plate can be machined with a high
level of accuracy such that a laser or robotic trimming device can
be used to automatically trim the TPU from the footwear. It should
be appreciated that the trim plate is constructed so that at least
a portion of the trim plate extends behind the cutting area so that
there is a firm surface for the cutting tool to press against
during the cutting process.
[0056] In an embodiment, the mold member 88 includes a die cutting
surface or surfaces 130 (FIG. 17), such as a wall, ridge or blade,
that extends from an inner surface of the mold member and is
positioned on the inner surface to cut the TPU at a designated
location or a plurality of locations on the base layer. The mold
member 88 may include one or more die cutting surfaces 130. In
operation, the die cutting surface or surfaces 130 of the mold
member 88 cut the TPU on the base layer at the designated location
or locations as it moves downwardly over the upper and/or sole
structure. As stated above, the liner 94 could be thicker in the
cutting areas to help prevent damage to the liner during the
thermoforming process. Also, the material forming the mold member
88, preferably silicone, can be thicker or added to the areas of
the mold member including the die cutting surfaces to apply uniform
pressure to the die cutting surfaces during cutting and to help
prevent the die cutting surfaces 130 from cutting or moving through
the mold member 88 from the pressure on the die cutting surface(s)
as the surfaces engage the platform supporting the upper 12 and/or
sole structure 50.
[0057] In another embodiment, one or more grooves are formed in the
upper, in one or more of the components and/or in the sole
structure to enable the excess TPU or other overmolded materials to
be easily removed from the upper, the components and/or the sole
structure. For example, FIG. 18 shows a groove 132 formed in the
sole structure 50, and more specifically, in an outsole. The
grooves act as a guide for a cutting tool so that a high level of
cutting accuracy is not needed during the cutting or trimming
process. Furthermore, the grooves help to hide the cut lines that
would otherwise be visible on the outer surface of the upper, the
components and/or the sole structure. Also, the width and/or depth
of the grooves can be adjusted to simplify the cutting or trimming
process. For example, a deep and narrow groove enables the excess
TPU to be manually torn away from the upper, the components and/or
the sole structure instead of cutting the excess TPU. A non-stick
coating can also be applied to the cutting lines or areas to
facilitate the removal of the excess TPU. It should be appreciated
that any suitable cutting or trimming method may be used to remove
the excess TPU from the upper, the components and/or the sole
structure.
[0058] The outsole 54 is now attached to the thermoformed upper 12
and sole structure 50 using conventional attachment methods such as
applying adhesive to and/or sewing the outsole to the bottom of the
sole structure, namely the midsole. Prior to attaching the outsole
54, the edge of the TPU sheet 76 extending from the midsole 52 is
cut and/or wrapped under the midsole so that the outsole secures
the edge of the TPU between the midsole and the outsole when the
outsole is attached to the midsole.
[0059] Alternatively, the thermoforming process may be used to
attach the outsole 54 to the midsole 52 such that the upper 12, and
the midsole 52 and the outsole 54 (collectively, the sole structure
50) are attached together by the TPU sheet 76. In an embodiment, an
adhesive strip or adhesive tape is placed against the inner
peripheral edge of the sole structure with the adhesive or sticky
side facing outward and extends along a portion of the last. The
bottom peripheral edge of the base material of the upper is then
pressed against the adhesive strip to hold the base material, and
thereby, the upper in place on the sole structure during the
thermoforming process. In another embodiment, a slot or groove is
formed along the peripheral edge of the sole structure so that the
base material curves inwardly and at least partially under the
upper to help hide the lower edge of the base material of the upper
attached to the sole structure. Additionally, in another
embodiment, a foxing material is attached over the seam between the
upper and the sole structure and secured in place during the
thermoforming process to further enhance the attachment of the
upper to the sole structure.
[0060] In a further embodiment, the sole structure is made with a
thermoplastic material, such as TPU, instead of rubber where the
thermoplastic material has similar or better wet traction
properties than rubber. Preferably, the sole structure is made with
softer grades of the thermoplastic material having a hardness value
of 50 to 60 Shore A. It should be appreciated that a thermoplastic
material having any suitable hardness value may be used. During the
thermoforming process, the TPU sheet is overmolded over the upper
and the sole structure such that the TPU sheets covers the entire
bottom surface of the sole structure to fixedly join the upper and
sole structure together. The TPU sheet preferably has a thickness
of one millimeter but may be any suitable thickness or combination
of thicknesses. In use, the TPU material on the bottom of the sole
structure wears away due to friction without any visible fraying
along the periphery of the sole structure while a strong bond is
maintained between the upper and the sole structure.
[0061] The thermoforming process described in the above embodiments
bonds various footwear components and a sole structure to a base
layer in a single step, which simplifies the footwear manufacturing
process, reduces toxic adhesives and solvents typically used in the
manufacturing process and significantly reduces labor costs. Also,
since the thermoforming process perfectly shapes the upper to the
last (shoe form) it requires little or no shaping inserts,
reinforcements or post heating or setting tunnels.
[0062] Referring to FIG. 13, in another embodiment, a base layer
110 including one or more materials 112 laminated with a TPU film
114 (the TPU is integrated in the base layer) is used to thermoform
the upper. The laminated base layer 110 is strobel lasted and
formed into a lasted upper 12, heated until the TPU film 114 in the
base layer is formable (thermal-forming) and then vacuum-formed as
described above. The laminated base layer 110 helps to eliminate
thinning of thermoformed materials during the process and controls
features of the TPU such as perforations, decorative features and
textures. The laminated material also helps to hide the appearance
of the TPU film/sheet (plastic appearance) on the outer surfaces of
thermoformed footwear. It should be appreciated that upper
materials, such as mesh and trim materials and/or the components,
can be made of the same thermoplastic as the overmolded or
integrated TPU, so that the materials all combine easily and form
at the same temperatures and pressures. By having only one formable
material layer for the base layer and the components, the process
is simplified, streamlined and more cost effective than
conventional footwear manufacturing processes.
[0063] In the above embodiment, the TPU laminated fabric may be
made into one or more rolls that are used in the thermoforming
process. Specifically, a part of a shoe, such as the upper, is cut
out of the laminated fabric roll and then one or more components
are attached to the shoe part and then thermoformed or overmolded
with a moldable material such as the TPU described above. In the
above embodiments, the laminated material may be attached to one
material or positioned between or attached between two or more
material layers where the heat formable material used to make the
laminated base layer or laminated material may include a sheet of
TPU, liquid TPU applied to a material or materials, TPU powder or
any suitable heat formable material.
[0064] In another embodiment, the lasted upper 12 can be molded in
an inverted or upside down position. During the thermoforming
process, the TPU sheet has a tendency to decrease in thickness,
i.e., thins, as it stretches over the upper and sole structure.
Thus, inverting the upper 12 controls the thinning of the TPU sheet
and thereby the thickness of the sheet and strengthens the bond
between the upper and sole structure. In particular, this process
is particularly effective for attaching an outsole to the midsole.
This process can also be used to secure sole components such as
rubber wear pads or logos to the sole structure via the overmolded
TPU. It also drives heat into these components to help adhere the
components to the sole structure. Any rubber components intended to
add traction or durability to the sole structure can be exposed
using a device similar to the "cover plate" or shield described
above or the TPU can simply be die cut to expose the rubber.
[0065] In an embodiment, the TPU sheet is texturized to add
perceived physical features and qualities to the upper and make the
TPU on the upper virtually invisible after the thermoforming
process is complete. In conventional methods, texture must be
embossed into the TPU sheet. During thermoforming, the texture
tends to melt out especially in deep draw thermoforming. By
attaching various stretch fabrics, particularly nylon based
fabrics, to the silicone liner in the mold member, an array,
including very fine textures, can be transferred to the TPU sheet
during the molding process. Preferably, a nylon-based material is
used to add texture to the TPU sheet as nylons do not adhere to
TPU. As such, the texturizing material should stretch as least 400%
in each direction, and preferably, 600% or more in each direction.
It should be appreciated that other suitable materials may be used
in place of fabric. Texturizing can also be accomplished by
pre-formed or shaped bladders that mimic the shape of an article of
footwear such as a shoe. These bladders have very defined textures
and geometries imprinted on them, including decorative and
functional geometries which are then transferred to the overmolded
thermoplastic on the shoe.
[0066] In another embodiment, to improve the breathability of the
base material and the circulation of air within the shoe, the TPU
sheet is pre-perforated with a plurality of holes prior to being
overmolded onto the upper and sole structure. The pre-perforated
TPU sheet is then accurately positioned between the upper and/or
sole structure and the mold member prior to heating and forming.
These holes will distort during thermoforming which can be
controlled via pre-distortion software design. The distortion of
the holes can also be controlled by attaching pre-perforated
materials to the upper.
[0067] Referring to FIG. 19, an inverted or a negative molding
process is illustrated where a base layer 134 and/or the components
136 are placed in a cavity 138 of a negative mold 140 such that the
inner surfaces of the base layer and/or the components are inverted
exposed inside of the upper. A heat formable material or other
formable material, such as a TPU sheet 142, is heated to be a
moldable TPU sheet 142' and then sheet 142'' is vacuum-formed to
the inner surfaces of the base layer 134 and the components 136 to
secure the base layer and the components together to form the
upper. The negative molding process enables the components to be
counter-sinked with the base layer and enables very fine textures
to be imprinted on the formable material.
[0068] Referring to FIG. 20, another embodiment of the inverted or
negative molding process is shown where a footwear upper 144, and
more specifically, a base material 145 of the upper is secured to a
last 146. The upper 144 is secured to a sole structure 145 that is
in turn, secured to a shoe retainer or shoe cassette 148 having a
shape that corresponds to the shape of the sole structure 145. To
secure the sole structure 145 to the shoe retainer 148, an inwardly
projecting edge is formed on the shoe retainer 148 such that the
sole structure 145 is pushed into an opening in the shoe retainer
until at least a portion of the sole structure 145 fits into or
snaps into the edge of the shoe retainer 148 to form a
tongue-in-groove type connection between the sole structure 145 and
the shoe retainer 148.
[0069] In the illustrated embodiment, the shoe retainer 148 is
attached to or integrally formed with a plate 150 that slides
within spaced mounting brackets 152 on the upper frame member 78 of
the thermoforming machine. The plate 150 may also be attached to
the upper frame member 78 by screws or other suitable connectors.
By having the shoe retainer 148 attached to the plate 150, the shoe
cassette or shoe retainer assembly is easily transferred to other
manufacturing machines and indexed to significantly enhance the
accuracy of the manufacturing process.
[0070] In this embodiment, the upper frame member 78 moves the
upper 144 downward into a heated TPU sheet 147 and then into a
corresponding bottom mold member 154 attached to the lower frame
member 62. The bottom mold member 154 includes a recessed area 156
with an inner surface having a shape that corresponds to the shape
of the upper 144 so that the upper moves into the bottom mold
member 154 during the thermoforming process. A non-stick liner 158
made of a silicone material or other suitable material is placed in
and secured to the bottom mold member 154. The liner 158 helps to
prevent the thermoformed upper from sticking to the bottom mold
member. Also as described above, in an embodiment, the liner 158
includes a textured surface for forming a corresponding texture in
the TPU on the upper.
[0071] In another embodiment, an upper is positioned on a sole
structure and a tape made of a thermoplastic material is heated and
placed over the seam between the upper and the sole structure such
that at least a portion of the tape extends onto the upper and the
sole structure. It should be appreciated that the tape may be made
out of any suitable material or combination of materials. After
being heated, the tape is then pressed onto the seam, similar to
the thermoforming process described above, to fixedly join the
upper to the sole structure. Alternatively, the tape is applied
without pre-heating it. It should be appreciated that the tape may
have a uniform width and thickness or may have different widths
and/or thicknesses depending on the location and positioning of the
tape. In embodiment, the thickness of the tape is one millimeter
but may any suitable thickness.
[0072] The thermoforming process described above, shapes and
combines various components to a base layer in one step,
significantly reducing the required labor, the amount of toxic or
hazardous adhesives and solvents and much of the traditional
equipment. Further, labor costs have skyrocketed, quality
production is very difficult and expensive to control and shipping
costs and import duties are also very expensive and energy
consuming. As a result, it has become very desirable to produce
footwear as close as possible to the point of consumer sale. For
example in an embodiment, the present thermoforming process is
employed in a retail machine, such as a footwear vending machine,
and thermoforms footwear based on predetermined styles that are
selected by a consumer or based on footwear components, styles and
colors selected by a consumer. In this way, such retail machines
can be placed at retail stores, malls, nightclubs, or any suitable
location. It should be appreciated that the retail machine may
manufacture shoes as described above based on any suitable
manufacturing process other than the thermoforming process. The
present footwear thermoforming process addresses these issues in a
positive way for footwear brands as well as the environment.
[0073] Moreover, footwear soles are generally attached to uppers by
adhesives. This process involves cleaning the surfaces of both the
sole and upper, buffing, priming and cementing the uppers and soles
together. After the adhesive dries, it is activated usually by heat
and then the upper and sole are carefully pressed together. This
process is fraught with problems and prone to operator mistakes and
is toxic or hazardous to workers and even to consumers. Further, a
significant percentage of the pollution associated with
manufacturing footwear is generated during this process. There are
other methods of attaching uppers to soles, however, the methods
are very limited with regard to materials, design and function.
Direct injection for instance, requires that the materials be
denser, and therefore heavy, and the associated equipment is
prohibitively expensive and does not fit into the rapid fashion
changes of modern retail. Sole stitching is also very restrictive
and not applicable to most types of shoes. The above footwear
thermoforming process of the entire shoe (including the sole
structure) with a thin layer of thermoplastic completely eliminates
the above chemical bonding and labor intensive processes.
[0074] Additionally, because thermoforming is a very low pressure
molding process, metal tooling and equipment typical in footwear
manufacturing are not necessary and usually not desirable. This
greatly reduces the tooling costs, new product lead times,
equipment changeover time and difficulty. Smaller lighter tools do
not require equipment to change and can easily be replaced at a low
cost if damaged. This is also an advantage since hotmelts and
thermoplastics are designed to adhere to anything these substances
contact.
[0075] In the above embodiments, the upper and/or sole structure
are thermoformed using a particular thermoforming process. It
should be appreciated that any suitable thermoforming process may
be used to form the upper and/or sole structure, including but not
limited to, drape molding and matched mold forming.
[0076] While particular embodiments of a thermoformed article of
footwear and method for thermoforming footwear have been described
herein, it will be appreciated by those skilled in the art that
changes and modifications may be made thereto without departing
from the invention in its broader aspects and as set forth in the
following claims.
* * * * *