U.S. patent application number 10/531116 was filed with the patent office on 2006-03-09 for shoe system with a resilient shoe insert.
Invention is credited to Hans Larsson, Kjell Lindh, Leif Lindh, Wilhelm Ove Lindqvist.
Application Number | 20060048411 10/531116 |
Document ID | / |
Family ID | 32392964 |
Filed Date | 2006-03-09 |
United States Patent
Application |
20060048411 |
Kind Code |
A1 |
Lindqvist; Wilhelm Ove ; et
al. |
March 9, 2006 |
Shoe system with a resilient shoe insert
Abstract
The method is for using a shoe system having a resilient shoe
insert. A shoe (300) has a shoe insert (500) disposed inside the
shoe. The insert has an upper leg (506) and a lower leg (514)
connected by a front end (502) with a curvature (512). The legs
(506, 514) have a concave segments (510, 518) and end points (520,
522), respectively; A load is put on the insert to compress the end
points towards one another. This shortens the effective length of
the legs (506, 514) because the legs are in contact at a contact
segment (524). This makes the insert stiffer the more it is
compressed. The effective length of the legs is shorter at the
outside (530) compared to the inside (532) so that the outside is
stiffer than the inside.
Inventors: |
Lindqvist; Wilhelm Ove;
(Stockholm, SE) ; Larsson; Hans; (Mjolby, SE)
; Lindh; Leif; (Danderyd, SE) ; Lindh; Kjell;
(Danderyd, SE) |
Correspondence
Address: |
FASTH LAW OFFICES (ROLF FASTH)
26 PINECREST PLAZA, SUITE 2
SOUTHERN PINES
NC
28387-4301
US
|
Family ID: |
32392964 |
Appl. No.: |
10/531116 |
Filed: |
October 8, 2003 |
PCT Filed: |
October 8, 2003 |
PCT NO: |
PCT/US03/31864 |
371 Date: |
April 11, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60319731 |
Nov 25, 2002 |
|
|
|
Current U.S.
Class: |
36/27 |
Current CPC
Class: |
A43B 13/026 20130101;
A43B 21/285 20130101; A43B 21/26 20130101; A43B 21/30 20130101;
A43B 13/12 20130101; A43B 13/187 20130101; A43B 13/203 20130101;
A43B 13/183 20130101 |
Class at
Publication: |
036/027 |
International
Class: |
A43B 13/28 20060101
A43B013/28 |
Claims
1. A method of using a shoe system having a resilient shoe insert,
comprising: providing a shoe having a shoe insert disposed inside
the shoe, the shoe insert having an upper leg and a lower leg
connected by a front end with an attachment segment, the upper leg
having an upper concave segment, the upper leg having an upper end
point and the lower leg having an lower end point that is separated
from the upper end point by a distance (d1), the insert having an
effective length (l.sub.1); putting a first load on the shoe and
the insert; compressing the upper end point towards the lower end
point until a concave the upper concave segment is in contact with
a lower concave segment of the lower leg at a contact point is
being remote from the attachment segment at the front end so that a
loop is formed between the attachment segment and the contact
segment, the contact segment being remote from both the upper and
the lower end points; and the upper concave segment being pressed
against and facing the lower concave segment; bending the
attachment segment until a contact point is formed when the upper
concave segment comes into contact with the lower concave segment;
putting a second load on the shoe and the insert, the second load
being substantially greater than the first load; bending the upper
leg and the lower leg at the contact point to form a contact
segment that extends from the contact point towards the upper and
lower end points and terminates at a separation point to
progressively increase a stiffness of the upper and lower legs; the
contact segment reducing the effective length (l.sub.1) to an
effective length (l.sub.2), the length (l.sub.2) extending from the
contact segment to the upper and lower end points.
2. The method according to claim 1 wherein the method further
comprises extending the contact segment from an outside to an
inside, the segment being substantially parallel to the front end,
the front end forming an acute angle to a longitudinal axis (A) of
the insert.
3. The method according to claim 2 wherein the method further
comprises further compressing the upper end point towards the end
point to reduce the distance (d2) to a distance (d3) that is
shorter than the distance (d2) and forming a contact area between
the upper leg and the lower leg.
4. The method according to claim 3 wherein the method further
comprises shortening the effective length (l.sub.2) to an effective
length (l.sub.3) at a mid-portion of the contact segment, the
length (l.sub.3) being shorter than the length (l.sub.2).
5. The method according to claim 4 wherein the method further
comprises providing the insert with an effective length (l.sub.30)
at the outside, the effective length (l.sub.30) being shorter than
the effective length (l.sub.3) at the mid-portion.
6. The method according to claim 5 wherein the method further
comprises providing the insert with an effective length (l.sub.3i)
at the inside, the effective length (l.sub.3i) being longer than
the effective length (l.sub.3) at the mid-portion.
7. The method according to claim 1 wherein the method further
comprises providing the attachment point with a curvature.
8. (canceled)
9. The method according to claim 1 wherein the method further
comprises aligning the upper concave segment with the lower concave
segment.
Description
TECHNICAL FIELD
[0001] The present invention relates to a resilient shoe spring
system that is intergrated with a shoe system.
BACKGROUND AND SUMMARY OF THE INVENTION
[0002] Users and developers of elastic shoes and shoe soles are
confronted with the problem of back injury and releasing the stored
energy in the shoe sole in a manner which improves walking and
running economy while at the same time achieving adequate
bio-mechanical shoe stability and cushioning. Many shoe
manufacturers have concentrated their effort on chock absorption by
permanently increasing the thickness of the shoe sole. This has
resulted in a slight change of the angle between the ankle and the
foot that may weaken the tendons of the foot. This change of the
angle may also lead to instability and reduced bio-mechanical
effect.
[0003] Many efforts have been made to develop an effective spring
mechanism for shoes or shoe soles. However, the earlier proposed
spring designs for shoe soles have not been entirely satisfactory.
Despite many elaborate shoe sole solutions, back injuries and other
injuries are still common due to poorly designed shoes. Injuries
due to poor shoe designs are particularly common in sports and
heavy duty work activities.
[0004] One important function of a shoe, such as a running shoe, is
to protect the foot from the stresses of running. The forces and
motions that occur in different sports vary greatly. Because of
these differences it is important that active participation in
varied sports require varied shoes. For example, tennis and other
racquet sports require much side-to-side motion and the shoe must
provide lateral stability. If the shoe is unstable and has high
heel elevation when the athlete is moving from one side to another
the likelihood is great the athlete may suffer an ankle sprain. The
majority of conventional shoes are not well designed. Some of
insufficiencies of the current shoe designs may be overcome by the
present invention.
[0005] The method and shoe system of the present invention provide
a solution to the above-mentioned problems. More particularly, the
method is for using a shoe system having a resilient shoe insert. A
shoe has a shoe insert disposed inside the shoe. The insert has an
upper leg and a lower leg connected by a front end with a
curvature. The upper and lower legs 506 have a concave segments and
end points. A load is put on the insert to compress the end points
towards one another. This shortens the effective length of the legs
because the legs are in contact at a contact segment. This makes
the insert stiffer the more it is compressed. The effective length
of the legs is shorter at the outside compared to the inside so
that the outside is stiffer than the inside.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a side view of a shoe insert of the present
invention;
[0007] FIG. 2 is a side view of a shoe adapted to receive the shoe
insert of FIG. 1;
[0008] FIG. 3 is a rear view of the shoe in a vertical position
along line 3-3 of FIG. 2 with the shoe insert of FIG. 1 placed
inside the shoe;
[0009] FIG. 4 is a rear view of the shoe along line 3-3 of FIG. 2
when the ankle is disposed in an inwardly sloping position;
[0010] FIG. 5 is a side view of a person standing straight up on
the shoe of the present invention;
[0011] FIG. 6 is a side view of a person standing on the shoe and
leaning forward;
[0012] FIG. 7 is a side view of an alternative embodiment of the
shoe insert of the present invention;
[0013] FIG. 8 is a top view of the shoe insert;
[0014] FIG. 9. is a top view of a second embodiment of a shoe
insert for the right shoe;
[0015] FIG. 10 is a top view of the second embodiment of the shoe
insert for the left shoe;
[0016] FIG. 11 is a bottom view of a third embodiment of a shoe
insert;
[0017] FIG. 12 is a side view of a fourth embodiment of a shoe
insert;
[0018] FIG. 13 is a side view of a fifth embodiment of a shoe
insert integrated with a shoe sole;
[0019] FIG. 14 is a side view of the fifth embodiment of the shoe
insert in a compressed position;
[0020] FIGS. 15A-D are schematic flow diagrams of a pressing
technique for manufacturing the shoe insert;
[0021] FIG. 16 is a top view of a sixth embodiment of the shoe
insert of the present invention;
[0022] FIG. 17a is a side view of the sixth embodiment in a relaxed
non-compressed position; FIG. 17b is a side view of the sixth
embodiment in a semi-compressed position so that the upper leg is
in contact with the lower leg;
[0023] FIG. 17c is a side view of the sixth embodiment in a
compressed position; FIG. 18 is a top view of the sixth embodiment
showing the varied effective lengths of the leg members; and
[0024] FIG. 19 is a schematic graphic illustration of a load L on
the shoe insert of the present invention.
DETAILED DESCRIPTION
[0025] With reference to FIGS. 1-8, the present invention is a shoe
system 10 having a resilient shoe insert 11 including a stiff first
support member 12 that may be made of a carbon fiber reinforced
composite material or any other suitable material that is
relatively stiff. The first member 12 has a flexible and bendable
fore end 14 and a stiff aft end 16. The fore end 14 has a cavity
portion 18 that terminates in a slightly upwardly curved end
section 20. It is to be understood that the fore end is preferably
made of a flexible and bendable material that may be cut to size by
a pair of scissors to tailor the shape of the fore end 14 to the
shape of the shoe system and the foot. Another reason for using the
flexible material at the fore end 14 is so that the toes of the
foot may fully cooperate with the fore end 14 when walking and
moving about.
[0026] The stiff aft end 16 has a cavity portion 22 that terminates
in a slightly upwardly curved end section 24. A stiff middle
section 26 of the member 12 is convex shaped relative to the
concave cavity portions 18, 22. A holder mechanism 26 is attached
to an underside 28 of the first member 12. The holder mechanism 26
includes a short end wall 30 that is perpendicular to the member 12
and a long support wall 32 that is perpendicularly attached to the
end wall 30 to that the underside 28, the end wall 30 and the
support wall 32 define a receiving pocket 34 that is facing the aft
end 16. Preferably, the end wall 30 is attached to the underside 28
on the first member 12 at a point 29 that is at a front-end portion
of the middle section 26. In the preferred embodiment, the first
member 12 is stiff all the way from the place of attachment at the
point 29 of the end wall 30 to the end section 24 and bendable from
the point 29 to the end section 20.
[0027] A second member 36 has a fore end 38 that is insertable into
the receiving pocket 34. More particularly, the second member has
the fore end 38 and an opposite aft end 40. The force end 38 has a
slightly downwardly curved end section 42 and the aft end 49 has an
upwardly curved end section 44 so that the second member 36 is
somewhat S-curved. When the second member 36 is inserted into the
receiving pocket 34, the end section 44 is aligned with the end
section 24 of the first member 12 so that a gap 46 is formed
between the first member 12 and the second member 36.
[0028] An important feature of the present invention is that the
second member 36 is springy and resilient while the first member 12
is generally stiff except for a bendable toe portion. As is
explained below, a heavier person may select a stiffer second
member than a lighter person to prevent the second member 36 from
abutting or resting against the first member 12 when the heavier
person is standing on the first member 12 with the second member 36
inserted into the receiving pocket 34. Preferably, the second
member 36 should be sufficiently stiff so that the second member 36
does not bottom out even though the person is actively using the
shoe insert 11 disposed in the shoe. For example, when a person is
standing straight up (as is shown in FIG. 5) so that the shoe
insert 11 is subjected to the greatest weight, the first member 12
form a minimum angle alpha relative to the second member 36 but the
angle should not be zero. The angle alpha increases when the person
bends his/her knees or leans forward, as is shown in FIG. 6, so
that an increasing amount of the body is supported by the front
portion of the foot and less weight is exerted upon the second
member 36. It is also preferred that the stiffness and the shape of
the second member 36 are such that the first member 12 does not
bottom out even though the person is jumping or actively using a
shoe 48.
[0029] Other factors that determine what stiffness to use for the
second member 36 include the type of activity the shoe is going to
be used for and whether the walking/running surface is hard, soft
and uneven. The shape of the second member 36 may also be varied
depending on the needs of the user. For example, a second member
having a more bent fore end creates a bigger gap 46 between the
second member and the first member when the second member is
inserted into the holder 32. A bigger gap 46 may reduce the risk of
bottoming out and also changes the angle between the foot and the
ankle.
[0030] Because the first member 12 is stiff, the shape of the first
member is maintained and the foot is provided a full support
although the second member 36 may move relative to the first member
12. In other words, the first member 12 provides good support to
the foot although the second member 36 may be compressed against
the first member 12 and later permitted to move back to the relaxed
expanded position depending upon how the shoe is used in, for
example, a sport activity.
[0031] As best shown in FIG. 2, the shoe 48 may have a preformed
shoe sole 50 that has an upper surface 52 that is shaped to snugly
receive the shoe insert 11. The shoe 48 has a heel section 51 and a
toe portion 53. The shoe sole 50 is preferably made of a flexible
material such as rubber or plastic. The upper surface 52 has an
upwardly curved front portion 54, a convex middle portion 56 and a
slightly upwardly curved aft portion 58 to support the sections 20,
26 and 24, respectively, of the first member 12.
[0032] An important feature is that the shoe sole defines an
angular curved groove 60 that is dimensioned to receive the second
member 36. The groove 60 extends backwardly and angularly
downwardly towards a heel 62 of the shoe 48. A triangular wedge 64
is disposed between the upper surface 52 and the groove 60. The
wedge 64 is removably attached to the sole 50 so that the wedge 64
easily be removed to make it convenient to insert and remove,
particularly, the second member 36 of the shoe insert 11. The wedge
64 is made of a very flexible material so when the second member 36
is urged towards the first member 12 by the weight of the user, the
wedge 64 is deformed and compressed accordingly.
[0033] The shoe 48 may also be used with the shoe insert 11 placed
on the upper surface 52 but with the wedge 64 removed. An one-way
valve 66 is attached to a back end 68 of the shoe 48. A channel 70
may be defined in the shoe sole 50 so that the valve 66 is in fluid
communication with a space 72 that is formed between the first
member 12 and the second member 36. Of course, the wedge 64 may
extend all the way back to the section 58 of the shoe sole 50 so
that there is no need for a channel.
[0034] When the second member 36 is pressed towards the first
member 12 so that the shoe insert 11 is in a compressed position,
an over pressure is formed in the space 72 that may flow into the
channel 70 and out through the valve 66 to provide good mechanical
ventilation inside the shoe. Any under pressure that may be formed
in the space 72 when the second member 36 is permitted to move from
the compressed position back to its original expanded position away
from the first member 12 may be equalized by sucking in air from an
upper part 74 of the shoe 48 such as the opening 76 or the open
areas adjacent to the shoe laces 78. It should be understood that
the valve 66 may also be a two-way valve so that the valve may be
used to compensate for both over-pressure and under-pressure in the
space 72. In this way, the valve 66 may function to circulate and
possibly bring in or suck cool air into the inside of the shoe when
the second member 36 is permitted to expand from the compressed
position. A filter 79 may also be placed in the valve 66 to prevent
dust and other undesirable particle from entering into the inside
of the shoe 48 when the shoe inlet 11 is expanding.
[0035] As best shown in FIG. 3, the first member 12 and the second
member 36 are substantially parallel when a person is standing
straight up without leaning sideways. The first member 12 may have
vertical sidewalls 81, 83 to prevent the foot from sliding sideways
and put undue pressure on the sidewall of the shoe. However, when
the person moves in a sideways direction so that an ankle 90 is in
an inclined position, the weight distribution of the shoe may be
uneven, as shown in FIG. 4, so that the second member 36 is twisted
slightly relative to the stiff first member 12 to create a torsion
force about an outside portion 82 of the second member 36. The
second member 36 may have a first thickness d.sub.1 on an inside
portion 80 and a second thickness d.sub.2 on the outside portion
82. The second thickness d.sub.2 is greater than the first
thickness d.sub.1 so that the second member 36 is only permitted to
twist relative to the stiff first member 12 when the ankle 90 is
leaned inwardly, as shown in FIG. 4, if the shoe 48 shown is a shoe
for the right foot. In other words, the second thickness at the
outside portion 82 is sufficiently thick to make the outside
portion 82 of the second member 36 rigid enough to prevent any
relative movement between the first member 12 and the second member
36 at the outside portion 82. Because the inside portion 80 is
twistable, there is less need to bend the ankle relative to the
foot, thus exposing the ankle to less strain, when the person is
standing with the legs wide apart. For example, it is common to
stand with the legs wide apart when waiting to return a serve in
tennis. Another situation that may put extra strain on the ankle is
when running along a surface that is sloping sideways. The twisting
of the inside portion 80 generally results in less risk of
straining the foot because the angle change between the ankle and
the foot as a result of, leaning the ankle inwardly is reduced.
[0036] FIG. 7 shows an alternative embodiment of the present
invention. The shoe insert 100 includes an extended back support
section 102 that extends above the heel of the foot to partly
protect the Achilles tendon and the heel of the foot. The support
section 102 reduces any excessive rubbing between the heel of the
foot and the rear inside wall of the shoe. Excessive rubbing may
cause blisters as the shoe insert 11 is compressed and expanded.
Similar to the shoe insert 11, the shoe insert 100 has a stiff
first member 104, a resilient second member 106 and a bendable and
flexible fore end 108 that may terminate at a toe portion 109 that
extends over the toes of the foot to protect the toes while the toe
portion 109 may follow the movement of the shoe insert. A resilient
rubber pad may be adhered to a bottom side of the fore end 108 to
provide extra comfort. The first member 104 and the second member
106 form an angle alpha therebetween. This embodiment is
particularly useful for working shoes and other types of heavy-duty
boots.
[0037] As best shown in FIG. 8, a transition area 77 between the
first member 12 and the soft and flexible fore end 14 may be a
curved section that is formed according to the support area of the
foot that is disposed behind the toes.
[0038] FIG. 9 is a top view of a second embodiment of the shoe
insert of the present invention. A shoe insert 200 has a transition
area 202 (that is equivalent to the transition area 77 of FIG. 8)
that extends at an angle so that a distance (x) at an inside 204 of
the shoe insert 200 is longer than a distance (y) at an outside
206. In other words, the flexible member is longer at the inside
204 than the outside 206 so that the inside 204 may flex (as shown
in FIG. 4) while the outside 206 is relatively stiff. Similarly,
FIG. 10 shows a top view of a shoe insert 210 for the left shoe
that has a transition area 211 and an inside 212 that has a length
(x) that is longer than a length (y) of an inside 214. FIG. 11 is a
bottom view of a third embodiment of the present invention. A shoe
insert 216 has an angular transition area 218 in addition to a
flexible member 220 that has a softer inside portion 222 and a
stiffer outside portion 224. In the third embodiment, it is not
necessary that the transition area extends at an angle because the
inside portion 222 is already softer than the outside portion 224.
FIG. 12 is a side view of a shoe insert 230 having a plurality of
flexible members 232, 234, 236 attached to an underside 238 of the
shoe insert 230 so that both the resiliency and the resiliency on
the inside and the outside may be adjusted to the specific needs of
the user of the shoe insert 230.
[0039] FIGS. 13 and 14 show a fifth embodiment of the present
invention. A shoe 300 has a shoe sole 302 including an upper layer
303 with a shoe insert 304 integrated with or built into the sole
302. The shoe 300 has a toe portion 330 and a heel portion 332 and
shoe sole 302 has a bottom side 305. The insert 304 has a
relatively stiff upper segment 306 and a bendable lower segment 308
that is attached to a lower side 310 of the segment 306 at a
mid-section 312 of the upper segment 306. The segment 306 is,
preferably, attached to a back piece 301 that is disposed at the
upper segment 303 adjacent to a backside 309 of the shoe 300. The
upper segment 306 and the lower segment 308 have a space 307
defined therebetween. The space 307 may be filled with air or a
very compressible and expandable material. The space 307 may be
completely or partially filled with a material. For example, the
material may include segments of an elastomeric material to change
the spring characteristics of the insert 304. Stiffer elastic
segments may be used if the person is heavy and less segments or
less stiff segments may be used if the person is relatively
light.
[0040] An important feature is that the segment 306 is stiff and is
attached to the sole so that the segment 306 does not move relative
to the shoe although the lower segment 308 may move relative to the
upper segment 306. This means that a foot inserted into the shoe
300 remains in the same position regardless of the flexural
movements of the lower segment 308. When the lower segment 308 is
in an expanded unloaded position (see FIG. 13) the distance between
the upper segment 306 and a bottom side 305 of the sole 302 is a
distance (A). However, when the shoe 300 is put under a load (L)
(see FIG. 14), the lower segment 308 moves into a compressed
position towards the upper segment 306 to reduce the distance
between the upper segment 306 and the bottom side 310 to a distance
(B) that is smaller than the distance (A). When the lower segment
308 is in the compressed position, the segment 308 urges the upper
segment 306 upwardly into the expanded position.
[0041] An important feature of the present invention is that upper
segment 306 is disposed at a distance (X) from an upper rim 314
both when the lower segment 308 is in the expanded position, as
shown in FIG. 13, and in the compressed position, as shown in FIG.
14. This means that there is little risk of blisters on a foot 316
placed in the shoe 300 between there is no relative movement
between the foot 316 and the shoe 300.
[0042] With reference to FIGS. 15A-D, the shoe insert of the
present invention is preferably made by using a unique pressing
method. The method relies on a tool 400 having a upper component
402 and a lower component 404. The component 402 has a cavity 406
defined therein that has the same shape as the upper segment 306
and the component 404 has a cavity 408 defined therein that has the
same shape as the lower segment 308. As best shown in FIG. 15B, the
components 404, 406 are separated from one another. A
pre-impregnated upper component 410 is placed, as shown by an arrow
A1, inside the cavity 406. The component 410 has an elongate
front-end portion 409 and an elongate back end portion 411 and a
shape that is similar to the shape of the cavity 406. A
pre-impregnated lower component 412 is placed in the cavity 408 and
has a shape that is similar to the shape of the cavity 408.
Preferably, the components 410, 412 and 414 are made of polymer
composites such as carbon and/or glass fiber reinforcements that
are impregnated with a suitable resin. The components may be fully
or partly impregnated. Preferably, the toe portions of the
components 410, 412 are partially impregnated to obtain an
increased bendability. The resin could be a suitable thermoplastic,
such as thermoplastic polyester, or a thermoset resin, such as
epoxy. Of course, other suitable polymers can also be used.
[0043] The component 412 has an elongate front-end portion 413 and
an elongate back portion 415. A U-shaped third component 414 is
placed between components 410, 412 to improve the physical
properties of a finished insert 424. The component 414 has
continuous fibers extending along the entire component 414 from one
end of the U-shaped component to an opposite end of the component
414. Surprisingly, the component 414 substantially reduces fiber
breakage and other failure characteristics of the insert 424.
Preferably, a sandwich construction is used so that the stiffer
carbon fibers may be placed on each side of the U-shaped component
414 that is, preferably, made of the less stiff glass fibers. Glass
fibers have better springing characteristics compared to carbon
fibers due to the high fatigue resistance properties of glass
fibers. In general, glass fibers are not as brittle as carbon
fibers. Carbon fibers may be used to partially or fully in the
components 410, 412. However, carbon fibers may also be used on the
inside of the component 414 in the form of carbon fiber tapes that
extend from a back portion 411, 415, respectively, of the
components 410, 412 towards a bottom 421 of the component 414. More
particularly, the component 414 has the bottom 421, an upper leg
416 and a lower leg 418. The upper leg 416 is placed along an
inside 420 of the back end portion 411 and the lower leg 418 is
placed along an inside 422 of the back portion 415. In this way,
both the upper leg 416 and the end portion 411 are placed inside an
elongate back end 417 of the cavity 406 and the both the lower leg
418 and the back end portion 415 are placed inside an elongate back
end 419 of the cavity 408. This means that the above described
sandwich construction may be used on the legs 416, 418 of the
components 410, 412 together with the component 414. Preferably,
the sandwich construction is not used for the portions 409, 413. A
resilient filler piece 423 may be placed between the legs 416, 418
prior to compression of the tool. The hardness of the piece 423 may
be adjusted depending upon the weight of the user. For example, a
more rigid piece 423 may be used if the user is heavy and a softer
piece 423 may be used if the user is relatively lightweight.
[0044] As best shown in the FIG. 15c, when the components 410, 412
with the third component 414 placed therebetween, are properly
positioned in the tool components 402, 404, the components 402, 404
are moved towards one another, as shown by arrows A2 and A3. A
pressure of between 2-40 bar is applied to the components 402, 404
for several minutes and the temperature is raised to between
100-250.degree. C. to enable the resin of the components 410, 412
to enable a thermoplastic resin to melt or a thermoset resin to
cure. The tool 400 may then be rapidly cooled before the components
are removed from the tool 400.
[0045] When the components 410, 412, 414 are cured into an
integrated shoe insert 424, the tool components 402, 404 are
separated from one another and the insert 424 is removed from the
components 402, 404, as shown by an arrow A4 in FIG. 15D. The
insert 424 is now ready to be integrated with or built into a shoe
sole as the insert 304 is shown in FIGS. 13-14.
[0046] FIG. 16 shows a sixth embodiment of a resilient shoe insert
500 of the present invention. The insert 500 may also be placed
inside the shoe 300, as shown in FIGS. 13-14, and replace the
insert 304 placed inside the shoe 300. The insert 500 has a slanted
straight front-end 502, a rounded back end 504 and a narrow
mid-section 506. The insert 500 may be made of a composite material
such as continuous fibers that extend from the back end 504, such
as from the outer end 520, around the front end 502 and back to the
back end 504, such as to the outer end 522. The fibers may also
merely extend from the back end to the front end.
[0047] With reference to FIGS. 17a-c, the shoe insert 500 has an
upper leg 506 with a straight upper leg segment 508 that terminates
in a concave upper segment 510. The leg segments 508, 516 may also
be slightly concave. Preferably, the segments 508, 516 are less
concave than the segment 510. The segment 510 extends to the
front-end 502 that is an attachment segment 512. The segment may be
a curved or pointed segment or any other suitable shape and the
present invention is not limited to a curved or pointed segment.
The insert 500 has a lower leg 514 with a straight lower leg
segment 516 that terminates in a concave lower segment 518 that is
adjacent to the concave upper segment 510. The segment 518 extends
to the front end 502. In this way, the fibers of the insert 500 may
extend from the upper leg 506 around the curved segment 512 to the
lower leg 514. The upper leg 506 has an upper end point 520 and the
lower leg 514 has a lower end point 522 that is separated by
distance d1 from the upper end point 520 when the insert 500 is not
compressed, as shown in FIG. 17A. The insert has an effective
length 11 that extends from the front end 502 to the end points
520, 522. It is to be understood that the shape of the legs 506,
514 may be straight, concave, convex or any suitable shape and the
stiffness of the legs 506, 514 may be the same or the stiffness of
the leg 506 may be different from the stiffness of the leg 514.
[0048] FIG. 17B shows the insert 500 in a semi-compressed position
so that the concave upper segment 510 is in contact with the
concave lower segment 518 in a contact segment or point 524. The
distance between the end points 520, 522 is reduced from the
distance d1 to the distance d2 that is shorter than the distance
d1. The effective length of the upper leg 506 and the lower leg 514
is reduced from the length 11 to the length 12 that is shorter than
the length 11. The effective length 12 extends from the points 520,
522 to the contact segment 524.
[0049] FIG. 17C shows the insert 500 in a compressed position so
that the upper leg 506 and the lower leg 514 is in contact over an
extended area 526 that starts at the contact point 524 and extends
backwardly to a separation point 528. The contact may extend all
the way back to the end points 520, 522 when the insert is
subjected to a sufficiently large load L. The distance between the
end point 520 and the end point 522 is reduced from the distance d2
to a distance d3 that is shorter than the distance d2. The
effective length of the legs 506, 514 is reduced from the length 12
to the shorter length 13. Preferably, the insert 500 is placed
inside a shoe, as shown in FIGS. 13 and 14, so that a person using
the shoe may compress the insert 500 as shown in FIGS. 17A-C.
[0050] FIG. 18 is a top view of the insert 500 and shows that the
effective length of the leg on a first side, such as an outside
530, is shorter than the effective length of the leg on a second
side, such as an inside 532, of the insert 500. As indicated
earlier, the front-end 502 and the contact segment 524 are slanted
at an acute angle alpha compared to the longitudinal direction L of
the shoe insert. The effective length l3 therefore varies along the
width W of the shoe insert. The effective length l.sub.30 on the
outside 530 is shorter than the effective length l.sub.3i on the
inside 532. This makes the outside 530 of the insert 500 stiffer
than the inside 532 similar to the embodiment shown in FIGS. 9 and
10. The stiffer outside makes the insert 500, and thus the shoe,
more stable. Also, the shorter the effective length l.sub.2,
l.sub.3 of the legs, the stiffer the insert 500 becomes. In this
way, the stiffness is not only varied by putting load on the insert
500 but the stiffness is also varied along the width of the
separation segment 528. The angle between the segment 524 and the
longitudinal axis L may be varied as shown by the contact segments
524a and 524b. Preferably, the insert 500 is removable and
replaceable from the shoe system should the user need different
stiffness characteristics of the insert 500.
[0051] FIG. 19 is a schematic graphic illustration of the load L on
the x-axis and the distance d on the y-axis. The surprising
increase in load L that is required to further reduce the distance
d2 to the smaller distance d3. Very little load L is required to
reduced the distance to d2. However a significant load increase is
required to further reduce the distance to d3. The relationship is
not linear but exponential.
[0052] While the present invention has been described in accordance
with preferred compositions and embodiments, it is to be understood
that certain substitutions and alterations may be made thereto
without departing from the spirit and scope of the following
claims.
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