U.S. patent application number 09/927649 was filed with the patent office on 2002-01-24 for work insoles.
Invention is credited to Crane, Laura, Goodrich, Kellie, Gray, Donald, Howlett, Harold, Rogers, W. Scott, Yang, Philip C..
Application Number | 20020007569 09/927649 |
Document ID | / |
Family ID | 23892668 |
Filed Date | 2002-01-24 |
United States Patent
Application |
20020007569 |
Kind Code |
A1 |
Crane, Laura ; et
al. |
January 24, 2002 |
Work insoles
Abstract
A full length insole for use with footwear, is formed by a first
layer including a forefoot portion extending at least to
metatarsals of a foot, a heel portion, a mid portion connecting
together the forefoot portion and the heel portion, the mid portion
including a medial arch portion, an upper surface extending along
the forefoot, mid and heel portions on which a person stands, and a
lower surface extending along the forefoot, mid and heel portions,
the lower surface including a shallow recess, the first layer being
made of a material of a first hardness; a force line insert secured
in the recess and having a shape that follows a greatest area of
force of the foot on the upper surface during a normal stride, the
force line insert being made of a material of a second hardness
which is less than the first hardness; a forefoot pillow formed as
a raised area at the upper surface at the forefoot portion to
provide additional cushioning thereat and shaped to conform to a
pressure area of the foot so as to include a front edge that
extends forwardly to a greater extent at a medial side of the
insole; and a heel pillow formed as a raised area at the upper
surface at the heel portion to provide additional cushioning
thereat and shaped to enhance progression of a gait to guide the
foot toward the medial arch portion.
Inventors: |
Crane, Laura; (Williston,
TN) ; Yang, Philip C.; (Memphis, TN) ;
Howlett, Harold; (Nesbit, MS) ; Goodrich, Kellie;
(Memphis, TN) ; Rogers, W. Scott; (Memphis,
TN) ; Gray, Donald; (Richmond, VA) |
Correspondence
Address: |
SCHERING-PLOUGH CORPORATION
PATENT DEPARTMENT (K-6-1, 1990)
2000 GALLOPING HILL ROAD
KENILWORTH
NJ
07033-0530
US
|
Family ID: |
23892668 |
Appl. No.: |
09/927649 |
Filed: |
August 10, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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09927649 |
Aug 10, 2001 |
|
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09476642 |
Dec 31, 1999 |
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Current U.S.
Class: |
36/44 ;
36/43 |
Current CPC
Class: |
A43B 17/003 20130101;
A43B 3/26 20130101; A43B 7/143 20130101; A43B 7/142 20130101; A43B
7/1464 20220101 |
Class at
Publication: |
36/44 ;
36/43 |
International
Class: |
A43B 013/18; A43B
013/38; A43B 023/00 |
Claims
What is claimed is:
1. A full length insole for use with footwear, comprising: a first
layer including: a forefoot portion extending at least to
metatarsals of a foot; a heel portion; a mid portion connecting
together said forefoot portion and said heel portion; an upper
surface extending along said forefoot, mid and heel portions and on
which a person stands; and a lower surface extending along said
forefoot, mid and heel portions, said lower surface including a
shallow recess; said first layer being made of a material of a
first hardness; and a force line insert secured in said recess and
having a shape that follows a greatest area of force of the foot on
said upper surface during a normal stride, said force line insert
being made of a material of a second hardness which is less than
said first hardness.
2. An insole according to claim 1, wherein said recess and said
force line insert each have a height of approximately 2 mm.
3. An insole according to claim 1, wherein said force line insert
and said recess have substantially the same shape and
dimensions.
4. An insole according to claim 1, wherein said first layer is made
from a urethane foam having a Shore "00" durometer hardness in the
range of approximately 45-75, and said force line insert is made
from a urethane foam having a Shore "00" durometer hardness in the
range of approximately 35-65.
5. An insole according to claim 4, wherein said first layer has a
Shore "00" durometer hardness in the range of approximately 55-65,
and said force line insert has a Shore "00" durometer hardness in
the range of approximately 45-55.
6. An insole according to claim 5, wherein said Shore "00"
durometer hardness of said first layer is approximately 60, and
said Shore "00" durometer hardness of said force line insert is
approximately 50.
7. An insole according to claim 1, wherein said force line insert
includes: a heel insert portion having a first width for
accommodating a heel of the foot during a heel strike and to
provide cushioning thereof; a mid insert portion connected at one
end with said heel insert portion and which has a second width less
than said first width; and a forefoot insert portion connected with
an opposite end of said mid insert portion and which has a shape
that extends forwardly to a greater extent at a medial side of the
insole in correspondence with a positioning of the metatarsals of
the foot.
8. An insole according to claim 1, wherein a forward edge of said
forefoot insert portion has an angled arcuate shape.
9. An insole according to claim 1, wherein said heel portion of
said insole is cupped to maintain said heel in said heel
portion.
10. An insole according to claim 1, wherein said mid portion
includes a medial arch portion positioned adjacent to said mid
insole portion.
11. An insole according to claim 10, wherein said medial arch
portion has a height greater than a remainder of said mid portion,
and includes spaced apart, transverse oriented grooves defining
transverse flex members therebetween which effectively function as
springs.
12. A full length insole for use with footwear, comprising: a
forefoot portion extending at least to metatarsals of a foot; a
heel portion; a mid portion connecting together said forefoot
portion and said heel portion, said mid portion including a medial
arch portion; an upper surface extending along said forefoot, mid
and heel portions on which a person stands; a lower surface
extending along said forefoot, mid and heel portions; a forefoot
pillow formed as a raised area at the upper surface at said
forefoot portion to provide additional cushioning thereat and
shaped to conform to a pressure area of the foot so as to include a
front edge that extends forwardly to a greater extent at a medial
side of said insole; and a heel pillow formed as a raised area at
the upper surface at said heel portion to provide additional
cushioning thereat and shaped to enhance progression of a gait to
guide the foot toward said medial arch portion.
13. An insole according to claim 12, wherein said forefoot and heel
pillows provide an extra thickness of the same material as a
remainder of said insole at said forefoot and heel portions, and
are formed integrally as a single molded piece therewith.
14. An insole according to claim 13, wherein said extra thickness
is less than approximately 3 mm.
15. An insole according to claim 12, wherein said heel pillow has a
shape of a wing that is oriented rearwardly.
16. An insole according to claim 15, wherein said wing has a
greater width at a rear portion thereof and tapers in width in a
forward direction, while also pointing toward said medial arch
portion.
17. A full length insole for use with footwear, comprising: a first
layer including: a forefoot portion extending at least to
metatarsals of a foot; a heel portion; a mid portion connecting
together said forefoot portion and said heel portion, said mid
portion including a medial arch portion; an upper surface extending
along said forefoot, mid and heel portions on which a person
stands; and a lower surface extending along said forefoot, mid and
heel portions, said lower surface including a shallow recess; said
first layer being made of a material of a first hardness; a force
line insert secured in said recess and having a shape that follows
a greatest area of force of the foot on said upper surface during a
normal stride, said force line insert being made of a material of a
second hardness which is less than said first hardness; a forefoot
pillow formed as a raised area at the upper surface at said
forefoot portion to provide additional cushioning thereat and
shaped to conform to a pressure area of the foot so as to include a
front edge that extends forwardly to a greater extent at a medial
side of said insole; and a heel pillow formed as a raised area at
the upper surface at said heel portion to provide additional
cushioning thereat and shaped to enhance progression of a gait to
guide the foot toward said medial arch portion.
18. An insole according to claim 17, wherein said force line insert
and said recess have substantially the same shape and
dimensions.
19. An insole according to claim 17, wherein said first layer is
made from a urethane foam having a Shore "00" durometer hardness in
the range of approximately 45-75, and said force line insert is
made from a urethane foam having a Shore "00" durometer hardness in
the range of approximately 35-65.
20. An insole according to claim 19, wherein said first layer has a
Shore "00" durometer hardness in the range of approximately 55-65,
and said force line insert has a Shore "00" durometer hardness in
the range of approximately 45-55.
21. An insole according to claim 20, wherein said Shore "00"
durometer hardness of said first layer is approximately 60, and
said Shore "00" durometer hardness of said force line insert is
approximately 50.
22. An insole according to claim 17, wherein said force line insert
includes: a heel insert portion having a first width for
accommodating a heel of the foot during a heel strike and to
provide cushioning thereof; a mid insert portion connected at one
end with said heel insert portion, positioned adjacent said medial
arch portion, and having a second width less than said first width;
and a forefoot insert portion connected with an opposite end of
said mid insert portion and which has a shape that extends
forwardly to a greater extent at a medial side of the insole in
correspondence with a positioning of the metatarsals of the
foot.
23. An insole according to claim 17, wherein a forward edge of said
forefoot insert portion has an angled arcuate shape.
24. An insole according to claim 17, wherein said medial arch
portion has a height greater than a remainder of said mid portion,
and includes spaced apart, transverse oriented grooves define
transverse flex members therebetween which effectively function as
springs.
25. An insole according to claim 17, wherein said forefoot and heel
pillows provide an extra thickness of the same material as a
remainder of said insole at said forefoot and heel portions, and
are formed integrally as a single molded piece therewith.
26. An insole according to claim 17, wherein said heel pillow has a
shape of a wing that is oriented rearwardly.
27. An insole according to claim 26, wherein said wing has a
greater width at a rear portion thereof and tapers in width in a
forward direction, while also pointing toward said medial arch
portion.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to insoles for
footwear, and more particularly, to improved insoles particularly
adapted for working people that spend much time on their feet.
[0002] There are many working people, such as construction workers,
cashiers, etc., that spend most of their working time in a standing
position. Further, much of this standing occurs on hard floors,
such as concrete floors or the like. This has the tendency to cause
lower back pain and lower extremity pain.
[0003] As a result of this pain, working people tend to alter their
posture and gait, in an attempt to alleviate this pain.
SUMMARY OF THE INVENTION
[0004] Accordingly, it is an object of the present invention to
provide an insole that overcomes the problems with the
aforementioned prior art.
[0005] It is another object of the present invention to provide an
insole that relieves lower back pain and lower extremity pain.
[0006] It is still another object of the present invention to
provide an insole which works faster and better than conventional
insoles in relieving lower back pain and lower extremity pain.
[0007] It is yet another object of the present invention to provide
an insole that provides cushioning and shock absorption at every
point along the foot stride.
[0008] It is a further object of the present invention to provide
an insole that provides additional shock absorption where needed at
high force areas along the foot stride.
[0009] It is a still further object of the present invention to
provide an insole that provides a biomechanical effect in rolling
through the gait, to enhance the stance and correct gait of the
foot.
[0010] In accordance with an aspect of the present invention, a
full length insole for use with footwear, comprises a first layer
including a forefoot portion extending at least to metatarsals of a
foot, a heel portion, a mid portion connecting together the
forefoot portion and the heel portion, an upper surface extending
along the forefoot, mid and heel portions and on which a person
stands, and a lower surface extending along the forefoot, mid and
heel portions, the lower surface including a shallow recess, the
first layer being made of a material of a first hardness; and a
force line insert secured in the recess and having a shape that
follows a greatest area of force of the foot on the upper surface
during a normal stride, the force line insert being made of a
material of a second hardness which is less than the first
hardness.
[0011] The recess and the force line insert preferably each have a
height of approximately 2 mm. Also, the force line insert and the
recess have substantially the same shape and dimensions.
Preferably, the first layer is made from a urethane foam having a
Shore "00" durometer hardness in the range of approximately 45-75,
with a more preferred range of approximately 55-65, and with a
preferred value of approximately 60, and the force line insert is
made from a urethane foam having a Shore "00" durometer hardness in
the range of approximately 35-65, with a preferred range of
approximately 45-55, and with a preferred value of approximately
50.
[0012] The force line insert includes a heel insert portion having
a first width for accommodating a heel of the foot during a heel
strike and to provide cushioning thereof; a mid insert portion
connected at one end with the heel insert portion and which has a
second width less than the first width; and a forefoot insert
portion connected with an opposite end of the mid insert portion
and which has a shape that extends forwardly to a greater extent at
a medial side of the insole in correspondence with a positioning of
the metatarsals of the foot. Preferably, a forward edge of the
forefoot insert portion has an angled arcuate shape.
[0013] In addition, the heel portion of the insole is cupped to
maintain the heel in the heel portion.
[0014] The mid portion includes a medial arch portion positioned
adjacent to the mid insole portion. The medial arch portion has a
height greater than a remainder of the mid portion, and includes
spaced apart, transverse oriented grooves defining transverse flex
members therebetween which effectively function as springs.
[0015] In accordance with another aspect of the present invention,
a full length insole for use with footwear, comprises a forefoot
portion extending at least to metatarsals of a foot; a heel
portion; a mid portion connecting together the forefoot portion and
the heel portion, the mid portion including a medial arch portion;
an upper surface extending along the forefoot, mid and heel
portions on which a person stands; a lower surface extending along
the forefoot, mid and heel portions; a forefoot pillow formed as a
raised area at the upper surface at the forefoot portion to provide
additional cushioning thereat and shaped to conform to a pressure
area of the foot so as to include a front edge that extends
forwardly to a greater extent at a medial side of the insole; and a
heel pillow formed as a raised area at the upper surface at the
heel portion to provide additional cushioning thereat and shaped to
enhance progression of a gait to guide the foot toward the medial
arch portion.
[0016] The forefoot and heel pillows provide an extra thickness of
the same material as a remainder of the insole at the forefoot and
heel portions, and are formed integrally as a single molded piece
therewith. The extra thickness is less than approximately 3 mm.
[0017] The heel pillow has a shape of a wing that is oriented
rearwardly. The wing has a greater width at a rear portion thereof
and tapers in width in a forward direction, while also pointing
toward the medial arch portion.
[0018] In accordance with still another aspect of the present
invention, a full length insole for use with footwear, comprises a
first layer including a forefoot portion extending at least to
metatarsals of a foot, a heel portion, a mid portion connecting
together the forefoot portion and the heel portion, the mid portion
including a medial arch portion, an upper surface extending along
the forefoot, mid and heel portions on which a person stands, and a
lower surface extending along the forefoot, mid and heel portions,
the lower surface including a shallow recess, the first layer being
made of a material of a first hardness; a force line insert secured
in the recess and having a shape that follows a greatest area of
force of the foot on the upper surface during a normal stride, the
force line insert being made of a material of a second hardness
which is less than the first hardness; a forefoot pillow formed as
a raised area at the upper surface at the forefoot portion to
provide additional cushioning thereat and shaped to conform to a
pressure area of the foot so as to include a front edge that
extends forwardly to a greater extent at a medial side of the
insole; and a heel pillow formed as a raised area at the upper
surface at the heel portion to provide additional cushioning
thereat and shaped to enhance progression of a gait to guide the
foot toward the medial arch portion.
[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 top plan view of a left insole according to the
present invention;
[0021] FIG. 2 is a top plan view of a right insole according to the
present invention;
[0022] FIG. 3 is a bottom plan view of the right insole of FIG.
2;
[0023] FIG. 4 is a bottom plan view of the left insole of FIG.
1;
[0024] FIG. 5 is a cross-sectional view of the left insole, taken
along line 5-5 of FIG. 1;
[0025] FIG. 6 is a cross-sectional view of the left insole, taken
along line 6-6 of FIG. 1; and
[0026] FIG. 7 is a cross-sectional view of the left insole, taken
along line 7-7 of FIG. 1.
DETAILED DESCRIPTION
[0027] As discussed above, there are many working people, such as
construction workers, cashiers, etc., that spend most of their
working time in a standing position. Further, much of this standing
occurs on hard floors, such as concrete floors or the like. This
has the tendency to cause lower back pain and lower extremity pain.
Further, these people also tend to alter their posture and gait, in
an attempt to alleviate this pain.
[0028] The present invention is designed to alleviate such lower
back pain and lower extremity pain, while enhancing the stance and
correct gait of the foot.
[0029] Referring to the drawings in detail, a left insole 10 and a
right insole 11 according to the present invention are adapted to
be placed in articles of footwear, as is well known. Insoles 10 and
11 are particularly adapted to alleviate lower back pain and lower
extremity pain. Only the left insole 10 will now be described, with
the understanding that right insole 11 will be the mirror image of
insole 10.
[0030] Specifically, insole 10 has the shape of a human left foot
and therefore includes a curved toe or forefoot portion 12, a heel
portion 14, and a mid portion 16 which connects forefoot portion 12
and heel portion 14 together. Heel portion 14 has a greater
thickness than toe portion 12. For example, heel portion 14 can
have a thickness of about 5-8 mm, while toe portion can have a
thickness of about 1-6 mm.
[0031] Insole 10 is formed by a lower layer 18 and a top cover 20
secured to the upper surface of lower layer 18, along forefoot
portion 12, cupped heel portion 14 and mid portion 16, by any
suitable means, such as adhesive, RF welding, etc.
[0032] Lower layer 18 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-butadienestyrene 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.
Non-foam elastomers such as the class of materials known as
viscoelastic polymers, or silicone gels, which show high levels of
damping when tested by dynamic mechanical analysis performed in the
range of -50 degrees C. to 100 degrees C. may also be
advantageously employed. A resilient polyurethane can be prepared
from diisocyanate prepolymer, polyol, catalyst and stabilizers
which provide a waterblown polyurethane foam of the desired
physical attributes. Suitable diisocyanate prepolymer and polyol
components include polymeric MDI M-10 (CAS 9016-87-9) and Polymeric
MDI MM-103 (CAS 25686-28-6), both available from BASF, Parsippany,
N.J.; Pluracol 945 (CAS 9082-00-2) and Pluracol 1003, both
available from BASF, Parsippany, N.J.; Multrinol 9200, available
from Mobay, Pittsburgh, Pa.; MDI diisocyanate prepolymer XAS
10971.02 and polyol blend XUS 18021.00 available from the Dow
Chemical Company, Midland, Mich.; and Niax 34-28, available from
Union Carbide, Danbury, Conn. These urethane systems generally
contain a surfactant, a blowing agent, and an ultra-violet
stabilizer and/or catalyst package. Suitable catalysts include
Dabco 33-LV (CAS 280-57-9,2526-71-8), Dabco X543 (CAS Trade
Secret), Dabco T-12 (CAS 77-58-7), and Dabco TAC (CAS 107-21-1) all
obtainable from Air Products Inc., Allentown, Pa.; Fomrez UL-38, a
stannous octoate, from the Witco Chemical Co., New York, N.Y. or
A-1(CAS 3033-62-3) available from OSI Corp., Norcross, Ga. Suitable
stabilizers include Tinuvin 765 (CAS 41556-26-7), Tinuvin 328 (CAS
25973-55-1), Tinuvin 213 (CAS 104810-48-2), Irganox 1010 (CAS
6683-19-8), Irganox 245 (CAS 36443-68-2), all available from the
Ciba Geigy Corporation, Greensboro, N.C., or Givsorb UV-1 (CAS
057834-33-0) and Givsorb UV-2 (CAS 065816-20-8) from Givaudan
Corporation, Clifton, N.J. Suitable surfactants include DC-5169 (a
mixture), DC190 (CAS68037-64-9), DC197 (CAS69430-39-3), DC-5125
(CAS 68037-62-7) all available from Air Products Corp., Allentown
Pa. and L-5302 (CAS trade secret) from Union Carbide, Danbury Conn.
Alternatively, lower 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).
[0033] Preferably, lower layer 18 is made from a urethane molded
material.
[0034] Top cover 20 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 20 include good
durability, stability and visual appearance. It is also desirable
that top cover 20 have good flexibility, as indicated by a low
modulus, in order to be easily moldable. The bonding surface of top
cover 20 should provide an appropriate texture in order to achieve
a suitable mechanical bond to the upper surface of lower layer 18.
Preferably, the material of top cover 20 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 20 is made from a polyester fabric
material.
[0035] Lower layer 18 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-cutting 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. Preferably, the innersole is
prepared by a foam reaction molding process such as taught in U.S.
Pat. No. 4,694,589.
[0036] During use, insole 10 is placed in a shoe so that the medial
side of mid portion 16 rests against the inside of the shoe.
Forefoot portion 12 may end just in front of the metatarsals.
However, insole 10 is preferably a full length insole, that is,
extends along the entire foot.
[0037] 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 22a-22d may be formed on the lower
surface of forefoot portion 12 of insole 10, and which are
representative of various sizes of the human foot. For example,
insole 10 may be provided for a woman's shoe size of 10-11, with
first continuous pattern trim line 22a being representative of a
smaller size insole for a woman's shoe size 9, second continuous
pattern trim line 22b extending around the periphery of toe portion
12 indicative of another size of insole for a woman's shoe size 8,
third continuous pattern trim line 22c extending around the
periphery of toe portion 12 indicative of another size of insole
for a woman's shoe size 7, and fourth continuous pattern trim line
22d extending around the periphery of toe portion 12 indicative of
another size of insole for a woman's shoe size 6. If the user
requires a size other than the original large size, the wearer
merely trims the insole with a scissors or cutting instrument,
using pattern trim lines 22a-22d, to achieve the proper size. The
pattern trim lines may be imprinted by conventional printing
techniques, silkscreening and the like. As an alternative, pattern
trim lines 22a-22d 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 a shoe.
[0038] In accordance with the present invention, insole 10 is
formed with a structure to alleviate lower back pain and lower
extremity pain. Specifically, insole 10 is provided with a shallow
recess 24 about 2 mm deep at the lower surface of lower section 18.
Shallow recess 24 follows the greatest line of force of the foot
during a normal stride, that is, in a single limb stance phase.
When walking, the foot first impacts at the heel with a large
force, for example, up to three times a normal standing force, and
then moves toward the forefoot. The heel lifts off of the insole
slightly at the position of contact of the mid-foot with the insole
and then transfers to the forefoot. At the forefoot, the foot
transfers from the position of the fifth metatarsal to the first
metatarsal, where push-off occurs at the big toe of the foot.
[0039] Shallow recess 24 has a shape to follow this line of force,
and to cover the high force areas during this stride.
[0040] In accordance with the present invention, a force line
insert 26 having a thickness of about 2 mm and having the same
shape as shallow recess 24, is secured within shallow recess. Force
line insert 26 is made from a softer or more cushioning material
than the remainder of lower section 18 of insole 10. For example,
lower section 18 of insole 10 can be made from a urethane foam
having a Shore "00" durometer hardness in the range of
approximately 45-75, more preferably in the range of approximately
55-65, and with a preferred hardness of approximately 60, while
force line insert 26 can be made from a softer urethane foam having
a Shore "00" durometer hardness in the range of approximately
35-65, more preferably in the range of approximately 45-55, and
with a preferred hardness of approximately 50. A preferred material
for force line insert 26 is the material sold by Rogers Corporation
of Rogers, Connecticut under the trademark "PORON". Preferably,
force line insert 26 is formed first, and then placed in a mold,
where the remainder of lower section 18 of insole 10 is molded
thereon, and thereby bonded to the PORON material of force line
insert 26 during the molding operation.
[0041] Thus, the force line shape of insert 26 provides a softer
material along the center of pressure of the gait line. As a
result, force line insert 26 provides cushioning and shock
absorption at every point along the stride.
[0042] As shown, force line insert 26 includes a heel insert
portion 26a of a width intended to accommodate the heel during the
heel strike and provide cushioning thereof. From heel insert
portion 26a, insert 26 tapers in width to a mid insert portion 26b
at mid portion 16. The reason for the taper is that the cushioning
material of insert 26 is not needed as much at this position, since
there is more surface area of the foot in contact with the upper
surface of insole 10 to spread out the forces more evenly, and
because, as will be explained hereinafter, the foot is guided
toward medial arch portion 16a of mid portion 16 which absorbs much
of the forces.
[0043] From mid insert portion 26b, insert 26 increases in width to
a forefoot insert portion 26c. Forefoot insert portion 26c has a
shape that extends forwardly to a greater extent at the medial side
of insole 10 in correspondence with the configuration of the
metatarsals. As a result, the forward edge of forefoot insert
portion 26c has an angled arcuate shape.
[0044] Thus, with the initial heel strike, heel insert portion 26a
functions to provide greater cushioning and shock absorbing at the
heel. As the foot moves forwardly, there is still a line of contact
at the mid-foot, but medial arch portion 16a also absorbs much of
the force, so as to provide an evening out of the force at the
mid-foot. As a result, the width of mid insert portion 26b can be
reduced. Thereafter, the foot transfers to the forefoot, and
particularly, from the fifth metatarsal to the first metatarsal,
where push-off occurs at the big toe of the foot. Such force can be
up to three times the normal standing force. Forefoot insert
portion 26c is shaped to follow this line of force, and provide
extra cushioning and shock absorbing during this action.
[0045] It will be appreciated that heel portion 14 is preferably a
cupped heel portion. Specifically, as shown, heel portion 14
includes a relatively flat central portion 14a, and a sloped side
wall 14b that extends around the sides and rear of central portion
14a. Generally, when a heel strikes a surface, the fat pad portion
of the heel spreads out. The cupped heel portion thereby stabilizes
the heel of the person and maintains the heel in heel portion 14,
to prevent such spreading out of the fat pad portion of the heel,
and to also prevent any side to side movement of the heel in heel
portion 14. This ensures that heel insole portion 26a operates
properly on the foot.
[0046] With respect to medial arch portion 16a, the arch can be
built into insole 10 in one of two ways. First, arch portion 16a
can be filled or built up with a bulky cushioning material. This,
however, provides the disadvantage that it might not be capable of
use in a shoe already having a built in arch support, since it may
be too bulky. Therefore, the preferred manner of forming medial
arch portion 16a according to the present invention is to build up
the height of medial arch portion 16a, but to provide spaced apart,
transverse oriented grooves or recesses 28 therein, which define
transverse flex members 30 therebetween which effectively function
as springs. The advantage of using flex members 30 is that the bulk
of arch portion 16a is not needed and thereby greatly reduced. It
therefore becomes easier and better to use flex members 30 with
shoes, since they can be used in shoes with or without a built in
arch support.
[0047] Flex members 30 function in concert with force line insert
26 to provide even cushioning support and shock absorption over the
entire mid-foot area during mid-stance phase. Because of flex
members 30, the width of mid insole portion 26b can be reduced. The
use of flex members 30, by themselves, however, has been known in
insoles sold more than one year ago, but the combination with force
line insert 26 is new.
[0048] In addition to force line insert 26, another important
feature of the present invention is the addition of forefoot pillow
32 and heel pillow 34.
[0049] Pillows 32 and 34 provide an extra thickness of the same
material as lower layer 18 and are formed integrally as a single
piece therewith during the molding operation of insole 10. Pillows
32 and 34 are provided at the two areas with the greatest force.
Since the cushioning energy is directly proportional to thickness,
the cushioning effect is normally achieved with increasing bulk of
the entire insole. The present invention accomplishes this by
increasing the bulk slightly by up to approximately 3 mm in
thickness above the upper surface of the insole, only at the areas
where the greatest forces result during walking.
[0050] When walking, the heel of the foot normally hits on the
outside of the heel and rolls toward the medial arch. Thus, pillow
34, in addition, to providing cushioning at the heel, is shaped to
enhance the rolling or progression of the gait, and thereby guides
the foot toward medial arch portion 16a. Thus, heel pillow 34
functions as a guide as well as providing extra cushioning. In this
regard, pillow 34 has the shape of a wing that is oriented
rearwardly. Thus, pillow 34 has a greater width at the rear portion
and tapers in width, while also pointing toward medial arch portion
16a.
[0051] At the forefoot, pillow 32 provides the same two functions.
Normally, when walking, the foot moves from the fifth metatarsal to
the first metatarsal and then the person pushes off from the big
toe. Pillow 32 thereby has a shape similar to forefoot insole
portion 26c, that is, with an arcuate front edge that extends
forwardly to a greater extent at the medial side of insole 10.
[0052] Pillows 32 and 34 thereby enhance the stance and correct
walking gait, while also providing cushioning.
[0053] Thus, while force line insert 26 provides cushioning and
shock absorption at every point, pillows 32 and 34 provide a
different function of shock absorption where needed, as well as a
biomechanical effect in aiding the foot in rolling through the
gait.
[0054] Tests were performed with insoles 10 and 11. Specifically,
103 people were evaluated over a four week period with insoles 10
and 11.
[0055] The following Table I shows a four week period of people
wearing insoles 10 and 11 on a visual analog scale (VAS), which is
a widely accepted method for evaluating pain.
1 TABLE I Variable Number of Mean VAS Standard (Back Pain) Subjects
Score Deviation Baseline 104 57.57 14.89 (week 0) Week 1 103 37.17
20.12 Week 2 103 30.81 19.93 Week 4 103 22.48 20.50
[0056] It will be appreciated that the back pain significantly
decreased from the baseline to week 1, and continued to decrease
thereafter to week 4. Similar tests with conventional insoles show
that, although many insoles normally relieve some pain, the present
invention works faster and better than conventional insoles that
provide shock absorption. Thus, the results of the tests with
insoles 10 and 11 showed significant relief of lower back pain and
lower extremity pain.
[0057] The change in back pain VAS score from the baseline is shown
by the following Table II:
2 TABLE II Variable (Change in Back pain Mean change Standard VAS)
in VAS score Deviation Prob > .vertline.T.vertline. Week 1 from
20.19 22.15 0.0001 Baseline Week 2 from 26.81 22.93 0.0001 Baseline
Week 4 from 35.14 23.90 0.0001 Baseline
[0058] In Table II, the designation Prob>.vertline.T.vertline.
refers to the probability that the data is significantly accurate
and relevant. The small percentage confirms the accuracy and
relevancy of the data.
[0059] The same analysis was performed with the lower extremity
pain, and is presented in Tables III and IV below:
3 TABLE III Variable (Lower Extremity Number of Mean VAS Standard
Pain) Subjects Score Deviation Baseline 104 35.56 23.00 (week 0)
Week 1 103 27.13 20.43 Week 2 103 25.32 22.10 Week 4 103 19.94
21.50
[0060]
4 TABLE IV Variable (Change in Lower Extremity Mean change Standard
Pain VAS) in VAS score Deviation Prob > .vertline.T.vertline.
Week 1 from 8.01 21.19 0.0002 Baseline Week 2 from 10.07 23.03
0.0001 Baseline Week 4 from 15.46 24.15 0.0001 Baseline
[0061] Subjective tests were also performed. At baseline week 0,
98% of the subjects considered insoles 10 and 11 moderately, very
or extremely comfortable. At week 4, 92.3% considered the insoles
moderately, very or extremely effective in relieving pain. Also, at
week 4, over 80% of the subjects considered that insoles 10 and 11
were moderately, very or extremely effective in relieving tired,
achy feet (83.5%) as well as tired, achy legs (81.3%).
[0062] Thus, insoles 10 and 11 provided significant relief of lower
back pain and lower extremity pain after only one week, with
further decreases in pain in weeks 2 and 4.
[0063] 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.
[0064] Further, although the present invention has been described
in connection with insoles, the present invention can be
incorporated directly into the sole of a shoe, and the present
invention is intended to cover the same. In this regard, reference
is made in the claims to a full length insole for use with
footwear, which can include a removable insole or an insole built
into a shoe.
[0065] 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.
* * * * *