U.S. patent application number 11/833067 was filed with the patent office on 2008-11-06 for gel insole.
This patent application is currently assigned to Schering-Plough Healthcare Products, Inc.. Invention is credited to Richard T. Avent, Bernard F. Grisoni, Charles E. Lundy, Philip C. Yang.
Application Number | 20080271340 11/833067 |
Document ID | / |
Family ID | 38798189 |
Filed Date | 2008-11-06 |
United States Patent
Application |
20080271340 |
Kind Code |
A1 |
Grisoni; Bernard F. ; et
al. |
November 6, 2008 |
Gel Insole
Abstract
An insole for insertion into footwear, comprising a forefoot
portion, a midfoot portion and a heel portion; the midfoot portion
connecting together the forefoot portion and the heel portion; said
insole comprising a cushioning layer of a viscoelastic gel material
which provides a cushioning function; and wherein the midfoot
portion and the heel portion comprise a peripheral edge that curves
upwards.
Inventors: |
Grisoni; Bernard F.;
(Cordova, TN) ; Yang; Philip C.; (Memphis, TN)
; Avent; Richard T.; (Memphis, TN) ; Lundy;
Charles E.; (Germantown, TN) |
Correspondence
Address: |
SCHERING-PLOUGH CORPORATION;PATENT DEPARTMENT (K-6-1, 1990)
2000 GALLOPING HILL ROAD
KENILWORTH
NJ
07033-0530
US
|
Assignee: |
Schering-Plough Healthcare
Products, Inc.
|
Family ID: |
38798189 |
Appl. No.: |
11/833067 |
Filed: |
August 2, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60835801 |
Aug 3, 2006 |
|
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Current U.S.
Class: |
36/43 |
Current CPC
Class: |
A43B 7/144 20130101;
A43B 7/143 20130101; A43B 7/1445 20130101; A43B 17/026 20130101;
A43B 7/142 20130101 |
Class at
Publication: |
36/43 |
International
Class: |
A43B 13/38 20060101
A43B013/38 |
Claims
1. An insole for insertion into footwear, said insole comprising a
forefoot portion, a midfoot portion and a heel portion; the midfoot
portion connecting together the forefoot portion and the heel
portion; said insole comprising a cushioning layer of a
viscoelastic gel material which provides a cushioning function; and
wherein the midfoot portion and the heel portion comprise a
peripheral edge that curves upwards.
2. An insole according to claim 1, wherein at least one of said
forefoot portion and said heel portion contains a substantially
dome shaped pillow protruding from said cushioning layer
thereat.
3. An insole according to claim 2, wherein said cushioning layer
and said pillow(s) are formed from the same viscoelastic gel
material as a unitary, one-piece structure.
4. An insole according to claim 3 wherein said pillow(s) are formed
from a material other than the viscoelastic gel material of the
insole.
5. An insole according to claim 4, wherein said pillow(s) are
formed from a foam material.
6. An insole according to claim 1, wherein said insole contains an
arrangement for maintaining said insole in position in said
footwear during use.
7. An insole according to claim 6, wherein said arrangement
comprises providing a high friction material on the surface of the
insole that contacts said footwear.
8. An insole according to claim 7, wherein said high friction
material comprises an adhesive applied to at least a portion of the
surface of the insole that contacts the footwear.
9. An insole according to claim 8, wherein said adhesive is a
release adhesive that permits removal of the insole from the
footwear and repositioning the insole in the footwear.
10. An insole according to claim 9, wherein said high friction
material comprises tackifier material added to said viscoelastic
gel material.
11. An insole according to claim 2, wherein said pillow(s) comprise
a plurality of spaced apart spring walls formed from said
viscoelastic gel, said spring walls extending from a lower surface
of said cushioning layer.
12. An insole according to claim 11, wherein said spring walls each
have a height which is greatest at a center of said pillow and
which tapers in height toward edges of said pillow.
13. An insole according to claim 11, wherein each of said spring
walls is formed in a generally sinusoidal wave shape.
14. An insole according to claim 1, wherein said cushioning layer
has a substantially uniform thickness of about 2 mm
15. An insole according to claim 2, wherein said pillow(s) have a
height less than about 3 mm.
16. An insole according to claim 1, further comprising a top cover
secured to an upper surface of said cushioning layer.
17. An insole for insertion into footwear comprising a forefoot
portion, a midfoot portion and a heel portion; said insole
comprising a cushioning layer of a viscoelastic gel material which
provides a cushioning function; wherein at least one of the
forefoot portion and heel portion comprising at least one
substantially dome shaped pillow protruding from the cushioning
layer; and wherein the insole comprises a peripheral edge that
curves upwards at the midfoot portion and the heel portion.
18. An insole according to claim 17, wherein said cushioning layer
and said pillow(s) are formed from the same viscoelastic gel
material as a unitary, one-piece structure.
19. An insole according to claim 17, wherein said pillow(s) are
formed from a material other than the viscoelastic gel material of
the insole.
20. An insole according to claim 19, wherein said pillow(s) are
formed from a foam material.
21. An insole according to claim 17, wherein said insole contains
an arrangement for maintaining said insole in position in said
footwear during use.
22. An insole according to claim 21, wherein said arrangement
comprises providing a high friction material on the surface of the
insole that contacts said footwear.
23. An insole according to claim 22, wherein said high friction
material comprises an adhesive applied to at least a portion of the
surface of the insole that contacts the footwear.
24. An insole according to claim 22, wherein said adhesive is a
release adhesive that permits removal of the insole from the
footwear and repositioning the insole in the footwear.
25. An insole according to claim 9, wherein said high friction
material comprises tackifier material added to said viscoelastic
gel material.
26. An insole according to claim 17, wherein said pillow(s)
comprise a plurality of spaced apart spring walls formed from said
viscoelastic gel, said spring walls extending from a lower surface
of said cushioning layer.
27. An insole according to claim 26, wherein said spring walls each
have a height which is greatest at a center of said pillow and
which tapers in height toward edges of said pillow.
28. An insole according to claim 26, wherein each of said spring
walls is formed in a generally sinusoidal wave shape.
29. An insole according to claim 17, wherein said cushioning layer
has a substantially uniform thickness of about 2 mm
30. An insole according to claim 17, wherein said pillow(s) have a
height less than about 3 mm.
31. An insole according to claim 17, further comprising a top cover
secured to an upper surface of said cushioning layer.
32. An insole according to claim 31, wherein the top cover
comprises a low friction film material.
33. An insole according to claim 32, wherein the film material
comprises a styrenic block copolymer.
34. The insole according to claim 33, wherein the film material
comprises a copolymer chosen from the group consisting of
styrene/ethylene-co-butylene/styrene (SEBS),
styrene/butadiene/styrene (SBS) and mixtures thereof.
35. An insole according to claim 34, wherein the gel film consists
essentially of SEBS, mineral oil and polypropylene.
36. An insole according to claim 32, wherein the film material
comprises the entire top surface of the gel insole.
37. An insole according to claim 32, wherein the film material
comprises only a portion(s) of the top surface.
38. An insole according to claim 37, wherein the insole comprises
film material covering only areas of the insole that will come in
contact with one or more of the toes, ball of foot, and heel when
in the insole comes in contact with a foot.
39. A method for constructing a gel insole comprising a
viscoelastic gel material to comprise a low friction top surface,
which method comprises the steps of placing a film material
comprising a styrenic block copolymer and having top and bottom
surfaces in an injection mold, and injecting viscoelastic gel
material into the mold to form the gel insole on the bottom surface
of the film material, thereby providing the low friction top
surface for the gel insoles.
40. A method according to claim 39, wherein the film material
comprises the entire top surface of the gel insole.
41. A method according to claim 39, wherein the film material
comprises only a portion(s) of the top surface of the gel
insole.
42. A method according to claim 41, wherein the insole comprises
film material covering only areas of the insole that will come in
contact with one or more of the toes, ball of foot, and heel when
in the insole comes in contact with a foot.
43. An insole comprising a forefoot portion, a mid-foot portion,
and a heel portion, said forefoot portion, mid-foot portion and
heel portion forming a cushioning layer comprising a resilient
material having a first hardness and which provides a cushioning
function, and a cushioning insert comprised within a recess in said
cushioning layer and extending down from said cushioning layer;
said cushioning insert comprising a resilient material having a
second hardness that is less than the hardness of said cushioning
layer.
44. An insole for insertion into footwear comprising a forefoot
portion, a mid-foot portion and a heel portion forming a cushioning
layer having upper and lower surfaces; which cushioning layer
comprises a first elastomeric gel material having a first hardness
and a second elastomeric gel material having a second hardness less
than the hardness of the first elastomeric gel material, said
second elastomeric gel material disposed within a recess in the
bottom surface of the cushioning layer, the recess located
substantially in the mid-foot portion positioned below the arch of
the foot.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of US Provisional
Application No. 60/835,7801 filed on Aug. 3, 2006.
BACKGROUND OF THE INVENTION
[0002] The present invention relates generally to shoe insoles or
inserts, and more particularly, to gel insoles particularly adapted
to provide greater stability within a shoe and to provide greater
support to the wearer.
[0003] Various types of insoles are known which fit within shoes in
order to correct various foot problems, alleviate pain and
otherwise provide more comfort to the wearer. Examples of such
insoles are those sold by the assignee of the present invention
under the trademark Dr. SCHOLL'S.RTM., in particular those
comprised of gel materials as described and claimed in U.S. Pat.
No. 6,598,321.
[0004] However, it would be useful and desirable to have a full
length insole formed of gel material that includes an upwardly
curved edge that contacts the outside edge of the foot without
constricting the forefoot. In particular, it would be useful and
desirable to construct such a full length insole where the upwardly
curved edge begins at a point behind where the ball of the foot
contacts the insole, so as to assist in maintaining contact between
the foot and the insole and prevent side-to-side movement of the
foot on the insole when pressure is exerted on the insole by the
foot.
[0005] Because of the viscous nature of the gel, the gel insoles
provide shock absorption and consequently protection to the foot.
One reason that gel insoles are popular is that they can be made
sufficiently thin to fit in shoes. The most common materials used
for making gels are polyurethane, silicone, and thermoplastic
rubber. However, because the materials used to make the gel insoles
typically exhibit a high coefficient of friction upon final
manufacture, the resulting insoles have a sticky feel at the
surface. Although this property is beneficial on lower surfaces of
insoles to keep them in place in shoes, a sticky top surface, which
contacts the foot, interacts unfavorably with skin or hosiery
materials. Fabric can be attached to the top surface of the gel
material as a means to eliminate the problem. However, the
additional step of adding the fabric adds cost to the process of
making the insole. If a non-fabric coated gel insole is desired,
the gel material can alternatively be dusted, usually with talc, to
lower the amount of friction. However, the dusting method is a
temporary solution, as the dusting material typically separates
from the gel material after a prolonged period of use, leaving the
sticky surface exposed. The dusting method also adds cost to the
production of insoles.
[0006] Moreover it has been surprisingly discovered that an arch
support insert comprising a gel material of a different hardness
than the gel material of the remainder of the insert provides an
improvement in arch support, shock absorption and overall
comfort.
[0007] These and other objectives are satisfied by the invention
described and claimed herein.
SUMMARY OF THE INVENTION
[0008] The present invention provides an insole for insertion into
footwear, said insole comprising a forefoot portion, a midfoot
portion and a heel portion; the midfoot portion connecting together
the forefoot portion and the heel portion; said insole comprising a
cushioning layer of a viscoelastic gel material which provides a
cushioning function; and wherein the midfoot portion and the heel
portion comprise a peripheral edge that curves upwards.
[0009] The invention also provides an insole for insertion into
footwear comprising a forefoot portion, a midfoot portion and a
heel portion; said insole comprising a cushioning layer of a
viscoelastic gel material which provides a cushioning function;
wherein at least one of the forefoot portion and heel portion
comprising at least one substantially dome shaped pillow protruding
from the cushioning layer; and wherein the insole comprises a
peripheral edge that curves upwards at the midfoot portion and the
heel portion.
[0010] In accordance with another aspect of the invention, the
insole comprises a forefoot portion, a mid-foot portion, and a heel
portion, said forefoot portion, mid-foot portion and heel portion
being formed by a cushioning layer of a resilient material having a
first hardness and which provides a cushioning function, and a
cushioning insert comprised within a recess in said cushioning
layer and extending down from said cushioning layer; said
cushioning insert comprising a resilient material having a second
hardness that is less than the hardness of said cushioning
layer.
[0011] In accordance with another aspect of the present invention,
an insole for insertion into footwear is provided which includes a
forefoot portion, a mid-foot portion and a heel portion and has a
cushioning layer having upper and lower surfaces; which cushioning
layer comprises a first elastomeric gel material having a first
hardness and within a recess in the bottom surface of the
cushioning layer a second elastomeric gel material having a second
hardness different from the hardness of the first elastomeric gel
material, the second elastomeric gel material located substantially
in the mid-foot portion to be positioned below the arch of the
foot.
[0012] The insole of the invention is a full length insole formed
from the forefoot portion, the heel portion and a mid-foot portion
connecting together the forefoot portion and the heel portion.
Preferably, the cushioning layer extends through the forefoot
portion, heel portion and mid-foot portion. Preferably, at least
one of the forefoot portion and heel portion includes at least one
substantially dome shaped pillow protruding down from the
cushioning layer thereat.
[0013] Preferably the cushioning layer and the pillow(s) are formed
from the same viscoelastic gel material as a unitary, one-piece
structure. In an alternative embodiment, the pillow(s) are formed
from a foam material.
[0014] The insole further may comprise an arrangement for
maintaining the insole in position in the footwear when the insole
is in use. The arrangement can comprise, for example, an adhesive
at a lower surface of the insole, for example a non-permanent
adhesive that permits removal of the insole from the footwear and
repositioning the insole in the footwear, or alternatively, a high
friction lower surface of the insole.
[0015] In another embodiment, the arrangement for maintaining the
insole in position includes a tackifier added to the gel material.
Preferably, the gel material forming the dome shaped pillow(s)
comprises a plurality of spaced apart spring walls formed from the
viscoelastic gel, the spring walls extending from a lower surface
of the cushioning layer. In one embodiment, the spring walls have a
height which is greatest at a center of the pillow and which tapers
in height toward edges of the pillow. Preferably, each of the
spring walls is formed in a generally sinusoidal wave shape.
[0016] Preferably, the cushioning layer has a substantially uniform
thickness of about 2 mm and the pillow(s) have a height less than
about 3 mm above the uniform layer.
[0017] The invention further comprises a top cover which can be
secured to an upper surface of the cushioning layer. Preferably the
top cover is a made of a low friction film material, which
preferably comprises a styrenic block copolymer.
[0018] The invention also provides a method for constructing a gel
insole comprising a viscoelastic gel material to comprise a low
friction top surface, which method comprises the steps of placing a
film material comprising a styrenic block copolymer and having top
and bottom surfaces in an injection mold, and injecting
viscoelastic gel material into the mold to form the gel insole on
the bottom surface of the film material, thereby providing the low
friction top surface for the gel insoles.
[0019] The above and other features of the invention will become
readily apparent from the following detailed description thereof
which is to be read in connection with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a perspective view of a left insole according to
one embodiment of the present invention;
[0021] FIG. 2 is a top plan view of the left insole;
[0022] FIGS. 3A and 3B are bottom plan views of the left and right
insoles, respectively, according to one embodiment;
[0023] FIG. 4 is a side elevational view of the right insole;
[0024] FIG. 5 is perspective view of one embodiment of a right
insole showing combination of gel film top cover and cloth top
cover;
[0025] FIG. 6 is top and bottom view of an embodiment of insoles
showing first and second gels of different hardness;
[0026] FIG. 7 is perspective view of one embodiment of a right
insole showing combination of gel film top cover and cloth top
cover;
[0027] FIG. 8 is perspective view of one embodiment of a left
insole showing combination of gel film top cover and cloth top
cover.
DETAILED DESCRIPTION
[0028] Referring to the drawings in detail, and initially to FIGS.
1-4 thereof, a left insole 10 according to a first embodiment of
the present invention is adapted to be placed in an article of
footwear, as is well known. A right insole (depicted in FIG. 3B) is
identical to left insole 10 and is a mirror image thereof.
[0029] As depicted in FIGS. 1 and 2, insole 10 is designed to fit
the shape of a human left foot and therefore includes a curved toe
or forefoot portion 12, a heel portion 14, and a mid-foot portion
16 which connects forefoot portion 12 and heel portion 14 together.
Cushioning layer 18, preferably generally planar throughout most of
the insole, curves upward at the peripheral edges of the midfoot
portion 30 and heal portion 32 of the insole in order to create a
cradle for the side, heel and arch of the foot.
[0030] In one embodiment shown in FIGS. 3A and 3B, insole 10
comprises a pillow 20 extending from the lower surface of
cushioning layer 18 at forefoot portion 12 and a generally dome
shaped, lower pillow 22 extending from the lower surface of
cushioning layer 18 at heel portion 14. Preferably, pillows 20, 22
are generally dome shaped.
[0031] As depicted in FIG. 4, cushioning layer 18 and pillows 20
and 22 are formed as a unitary, one-piece layer of the same
viscoelastic gel material. In an alternative embodiment, the
pillows 20 and 22 are formed from a different material that the
viscoelastic gel material of the cushioning layer 18. Specifically,
in said alternative embodiment, pillows 20 and 22 can be made from
a resilient foam material that provides a conventional cushioning
function. As such, pillows 20 and 22 form a typical foam mechanical
spring, shock absorption layer that cushions the foot, in order to
decrease pressure. Cushioning layer 18 is preferably made from
non-foam elastomers such as the class of materials known as
viscoelastic gel polymers as described in U.S. Pat. No. 6,598,321,
which show high levels of damping when tested by dynamic mechanical
analysis performed in the range of -50.degree. C. to 100.degree. C.
Because the mechanical properties of the gel are more viscous than
elastic, the gel provides a high energy absorption. Gels that can
be used according to the present invention are thermoplastic
elastomers (elastomeric materials), such as materials made from
many polymeric families, including but not limited to the Kraton
family of styrene-olefin-rubber block copolymers, thermoplastic
polyurethanes, thermoplastic poly olefins, polyamides, polyureas,
polyesters and other polymer materials that reversibly soften as a
function of temperature. The preferred elastomer is a Kraton block
copolymer of styrene/ethylene-co-butylene/styrene or
styrene/butadiene/styrene with mineral oil incorporated into the
matrix as a plasticizer. In one embodiment, cushioning layer 18 can
be a laminate construction, that is, a multilayered composite of
any of the above materials. Multilayered composites are made from
one or more of the above materials such as a combination of
polyethylene vinyl acetate and polyethylene (two layers), a
combination of polyurethane and polyvinyl chloride (two layers) or
a combination of ethylene propylene rubber, polyurethane foam and
ethylene vinyl acetate (3 layers).
[0032] When made of a different material than cushioning layer 18,
pillows 20 and 22 can be made from any suitable material including,
but not limited to, any flexible material which can cushion and
absorb the shock from heel strike on the insole. Suitable shock
absorbing materials can include any suitable foam, such as but not
limited to, cross-linked polyethylene, poly(ethylene-vinyl
acetate), polyvinyl chloride, synthetic and natural latex rubbers,
neoprene, block polymer elastomer of the
acrylonitrile-butadiene-styrene or styrene-butadiene-styrene type,
thermoplastic elastomers, ethylenepropylene rubbers, silicone
elastomers, polystyrene, polyurea or polyurethane; most preferably
a polyurethane foam made from flexible polyol chain and an
isocyanate such as a monomeric or prepolymerized diisocyanate based
on 4,4'-diphenylmethane diisocyanate (MDI) or toluene diisocyanate
(TDI). Such foams can be blown with freon, water, methylene
chloride or other gas producing agents, as well as by mechanically
frothing to prepare the shock absorbing resilient layer. Such foams
advantageously can be molded into the desired shape or
geometry.
[0033] The materials of cushioning layer 18 and pillows 20 and 22
can be prepared by conventional methods such as heat sealing,
ultrasonic sealing, radio-frequency sealing, lamination,
thermoforming, reaction injection molding, and compression molding
and, if necessary, followed by secondary die-cuffing or in-mold die
cutting. Representative methods are taught, for example, in U.S.
Pat. Nos. 3,489,594; 3,530,489 4,257,176; 4,185,402; 4,586,273, in
the Handbook of Plastics, Herber R. Simonds and Carleton Ellis,
1943, New York, N.Y., Reaction Injection Molding Machinery and
Processes, F. Melvin Sweeney, 1987, New York, N.Y., and Flexible
Polyurethane Foams, George Woods, 1982, New Jersey, whose
preparative teachings are incorporated herein by reference. For
example, the innersole can be prepared by a foam reaction molding
process such as taught in U.S. Pat. No. 4,694,589.
[0034] In the embodiment shown in FIGS. 3A and 3B and FIG. 4,
pillows 20 and 22 extend downwardly below the lower surface of
cushioning layer 18 to provide extra cushioning at the ball of the
foot area of forefoot portion 12 and at heel portion 14. In equally
preferred embodiments, the arrangement of the material can result
in the pillows protruding upward from the surface of cushioning
layer 18. Preferably, cushioning layer 18 has a constant thickness
throughout. For example, cushioning layer 18 can have a thickness
of about 2 mm and the pillow 20 or 22 preferably having a thickness
of about 3 mm. Thus, the combined thickness of cushioning layer and
any pillow 20 or 22 would preferably have a thickness of about 5
mm.
[0035] As depicted in FIG. 5 top cover layer 24 can be secured to
the upper surface of cushioning layer 18, although such a top cover
layer 24 is not required. In such case, top cover layer 24 can be
made from any suitable material including, but not limited to,
fabrics, leather, leatherboard, expanded vinyl foam, flocked vinyl
film, coagulated polyurethane, latex foam on scrim, supported
polyurethane foam, laminated polyurethane film or in-mold coatings
such as polyurethanes, styrene-butadiene-rubber,
acrylonitrile-butadiene, acrylonitrile terpolymers and copolymers,
vinyls, or other acrylics, as integral top covers. Desirable
characteristics of top cover layer 24 include good durability,
stability and visual appearance. It is also desirable that top
cover layer 24 have good flexibility, as indicated by a low
modulus, in order to be easily moldable. The bonding surface of top
cover layer 24 should provide an appropriate texture in order to
achieve a suitable mechanical bond to the upper surface of
cushioning layer 18. Preferably, the material of top cover layer 24
is a fabric, such as a brushed knit laminate top cloth (brushed
knit fabric/urethane film/non-woven scrim cloth laminate) or a
urethane knit laminate top cloth. Preferably, top cover layer 24 is
made from a polyester fabric material, and preferably has a
thickness of about 0.02 inch.
[0036] Preferably the insoles of the present invention comprise a
top cover 24 comprising a self adhesive low friction film material
26. The film material is chosen to be compatible with the gel
material that comprises the remainder of the insole, described
above. In one embodiment, the film material comprises a
polyurethane when the gel material in the insole comprises
polyurethane. In another embodiment, the film material comprises a
styrenic block copolymer, such as the Kraton block copolymer of
styrene/ethylene-co-butylene/styrene (SEBS) or
styrene/butadiene/styrene (SBS) described above for the cushioning
layer 18 when the gel material in the insole comprises styrenic
block copolymers. As explained above, these copolymers comprise
mineral oil incorporated into the matrix as a plasticizer,
typically in high content of the gels, such as greater than 50%,
and in some embodiments greater than 70% by weight and can be
difficult to mechanically attach woven top cloth to the upper
surface. It has been found that a gel film material comprising a
styrenic block copolymer such as SEBS with mineral oil and
polypropylene produces a suitable film material that can be added
to an injection mold before the mold is loaded with the gel
material to form the cushioning layer 18, thereby providing the low
friction gel film top cover for the gel insoles of the invention.
In certain embodiments, the gel film top cover can cover the entire
top surface of the gel insole or can comprise only portions of the
top surface. Thus, for example, as depicted in FIGS. 5-8, the gel
film top cover can be used in addition to the other top surface
material described above, whereby part of the top surface of the
insole is a woven fabric or other material and part of the top
surface is a gel film top cover. In certain embodiments, the gel
film top cover will comprise only certain higher pressure points
such as those areas of the insole 10 that will come in contact with
the toes, ball of foot, and/or heel. Because the gel material of
certain embodiments of insole 10 and the get film top covers are
substantially translucent, the arrangement of partial gel film top
cover portions can be made to provide a decorative pattern as
well.
[0037] As depicted in FIG. 6, in a further embodiment of the
invention, cushioning layer 18 comprises a first elastomeric gel
material 40 having a first hardness and within a recess in the
bottom surface of the cushioning layer a second elastomeric gel
material 42 having a second hardness different from the hardness of
the first elastomeric gel material, the second elastomeric gel
material located substantially in the mid-foot portion, preferably
to be positioned below the arch of the foot. In a preferred
embodiment, the first elastomeric gel material has a greater
hardness than the second elastomeric gel material. For example the
first elastomeric material may have a Shore OO hardness of between
about 50 to about 65, preferably between about 55 to about 65, most
preferably about 55. The second elastomeric gel material may have a
Shore OO hardness of between about 30 to about 45, preferably
between about 40 to about 45, most preferably about 45.
[0038] It will be appreciated that insole 10 is a full length
insole extending along the entire foot. Typically, insole 10 would
be sized corresponding to shoe sizes and would be provided in sized
pairs. Alternatively, insole 10 may be trimmed to the requirements
of the user. In this regard, arcuate pattern trim lines (not shown)
may be formed on the lower surface of forefoot portion 12 of insole
10, which are representative of various sizes of the human foot.
The pattern trim lines may be imprinted by conventional printing
techniques, silkscreening and the like. As an alternative, the
pattern trim lines may be formed as shallow grooves, or be
perforated, so that a smaller size insole may be separated by
tearing along the appropriate trim lines, which tearing operation
is facilitated by the inclusion of perforations. Thus, forefoot
portion 12 can be trimmed so that forefoot portion 12 fits within
the toe portion of open style footwear.
[0039] Alternatively, a pattern trim line can be provided on the
lower surface of cushioning layer 18 to cut around the thong of
some types of open style footwear, if necessary.
[0040] In order to secure insole 10 to footwear, an area of
adhesive 26, for example, by a double sided adhesive tape, is
formed along the length of the lower surface of cushioning layer
18, and is covered by a release sheet 28. In this manner, a user
merely removes release sheet 28 and adheres insole 10 to the
footwear. Adhesive 26 can be a permanent adhesive or a release
adhesive that permits removal and reapplying or repositioning of
insole 10 in the footwear.
[0041] Alternatively, lower surface of cushioning layer 18 can be
provided as a high friction surface to maintain insole 10 in
position in the footwear. For example, synthetic rubber adhesive
coating (not shown) can be added to lower surface 18a of cushioning
layer 18 for this purpose.
[0042] Accordingly, with insole 10, cushioning pillows 20 and 22
are provided at the ball of the foot area of forefoot portion 12
and at heel portion 14 where most of the impact and forces occur
during a gait. Further, such insole 10 fits within footwear, and
will remain in position in such open style footwear during wearing
by the user. Moreover, because of the upward curvature of the
peripheral edges, the wearer experiences a more secure fit between
the foot and insole, thereby enhancing comfort to the wearer.
[0043] Insole 10 can be also be secured to the footwear by using
the tack properties of the gel. In this regard, it is preferred
that the tack of the gel is enhanced by incorporating a tackifier
into the gel composition to increase the friction/tack of the gel
surface. Suitable tackifiers include a petroleum hydrocarbon resin
sold under the designation I-Mark V by Idemitsu Kosan Co., Ltd. of
Tokyo, Japan; the rosin sold under the trademark ASYLVALITE.RTM.
under designation RE 80 for SEBS gels; and phenolsulfonic acid
ester sold under the trademark AMESAMOLL.RTM. for a polyurethane
(PU) gel. The desired tack is preferably between 120 and 250 grams,
as determined by a probe tack tester sold under the trademark
APOLYKEN.RTM., at one second contact time.
[0044] Although the present invention uses the term insole, it will
be appreciated that the use of other equivalent or similar terms
such as innersole or insert are considered to be synonymous and
interchangeable and thereby covered by the present claimed
invention.
[0045] Having described specific preferred embodiments of the
invention with reference to the accompanying drawings, it will be
appreciated that the present invention is not limited to those
precise embodiments and that various changes and modifications can
be effected therein by one of ordinary skill in the art without
departing from the scope or spirit of the invention as defined by
the appended claims.
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