Note: Descriptions are shown in the official language in which they were submitted.
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OUTER SOLE HAVING RESILIENT MID-SOLE WITH FLOATING HINGES
FIEI.D OF THE INVENTION
The invention relates to a sole having foot cushioning means. In particular,
the invention
relates to an outer sole for a shoe or boot, having a resilient mid-sole for
cushioning the
foot while walking or running.
BACKGROUND OF THE INVENTION
With the increasing popularity of low-impact forms of cardiovascular exercise,
several
walking and athletic shoe designs have emerged that are intended to cushion
the foot
from impact.
For instance, Schwab (US 3,662,478) describes a shoe sole having a tread
profile
consisting of a longitudinal rib, and several lateral grooves that branch off
from the
longitudinal rib. The grooves are inclined at an angle not exceeding 90 ,
relative to the
longitudinal rib. The grooves create several lateral ribs over which the load
of the walker
is distributed.
Stubblefield (US 4,372,058) describes a shoe sole having flexible lugs that
extend
downwardly from the lower surface of the sole. The lugs are inclined at an
obtuse angle
relative to the lower surface, and spread outwardly upon inipact with the
ground.
Cohen (US 4,754,559) describes a shoe having a mid-sole, an outer sole, and
plurality of
rib-pairs disposed between the mid-sole and the outer sole. The rib-pairs are
provided
along the entire length of the shoe, each comprising a pair of oppositely-
bowed ribs that
extend transversely to the longitudinal axis of the shoe. The ribs are
constructed from a
rubber or similat material. The oppositely-bowed ribs of each rib-pair are
separated from
one another by a distance that allows the rib-pairs to deform as the load on
the shoe
increases. After a predetermined load is applied, one of'the ribs of each rib-
pair abuts the
adjacent oppositely-bowed rib, to thereby increase the load required for
further
deformation of the rib-pairs.
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Diaz (US 4,815,221) describes a shoe sole having a spring plate and several
curved,
tubular resilient lugs projecting downwards or upwards from the plate. The
resilient lugs,
which have a substantially U-shaped cross-section, are deformed under the load
of the
foot, and return to their uncompressed state when the foot is lifted. A
support rib
positioned at the rear of each lug urges each lug forward as the lug returns
to its
uncompressed state.
Sessa (US 5,469,639) describes a shoe outsole having a recess formed in its
upper
surface, and a resilient midsole insert positioned within the recess. The
insert has several
longitudinally-spaced, downwardly extending transverse ribs that extend across
the lower
surface of the insert. The transverse ribs are of two lengths, with the longer
ribs
alternating with the shorter ribs in a regular pattern along the length of the
insert. The
ribs are disposed in a sinusoidal pattern across the width of the insert, with
the height of
each rib varying in a sinusoidal pattern across the width of the insert. The
taller ribs
provide a first cushioning rate, while the short ribs provide a gradually-
increasing
cushioning rate upon further compression of the ribs.
Parisotto (GB 2 297 76$) describes a shoe outersole having a cavity disposed
in the upper
surface of the outersole, at the heel portion thereof, and a central
longitudinal rib and
several transverse ribs disposed within the cavity. The transverse ribs
intersect the
longitudinal rib, to thereby form a grid pattern. The transverse ribs extend
upwards from
the upper surface of the cavity, and are inclined rearwardly towards the rear
of the shoe.
In use, the transverse ribs flex rearwardly under the weight of the heel of
the foot, and
return to their undeformed position when the foot is lifted.
Lekhtman (WO 2005/025381) describes a cushioning outsole comprising an upper
load
bearing member, a lower load bearing member, a plurality of compressible
spring
members disposed between the load bearing members. Each compressible spring
member
has a bi-concave V-shape, and comprises a pair of arcuate panels that are
contiguous with
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one another at one end, and are pivotally coupled to a respective load bearing
member via
bearing means provided at their respective opposite ends.
SUMMARY OF THE 7NVENTION
According to one aspect of the invention, there is provided an outer sole
comprising an
upper sole, a tread layer disposed below the upper sole, and a resilient mid-
sole disposed
between the upper sole and the tread layer and being configured to resist
compression
under load. The mid-sole comprises at least one floating hinge extending
transversely to
the longitudinal axis of the sole. Each floating hinge includes an upper
resilient convex
leaf spring, a lower resilient convex Ieaf spring, and a U-spring joining the
lcaf springs
together. Each leaf spt'ting has a root and a head opposite the root, Each U-
spring has a
pair of integrally-formed legs, each upper leaf spring is integrally formed at
the root
thereof with the upper sole, and each lower leaf spring is integrally formed
at the root
thereof with the tread layer. The leaf springs of each floating hinge are
integrally joined
at their respective heads to a respective one of the legs of the associated U-
spring.
According to another aspect of the invention, there is provided a foot
covering
comprising a shoe upper, and an outer sole secured to the sole upper. The
outer sole
comprises an upper sole, a tread layer disposed below the upper sole, and a
resilient mid-
sole disposed between the upper sole and the tread layer and being configured
to resist
compression under load. The mid.sole comprises at least 4n.e floating hinge
extending
transversely to the longitudinal axis of the sole. Each floating hinge
includes an upper
resilient convex leaf spring, a lower resilient convex leaf spring, and a U-
spring joining
the leaf springs together. Each leaf spring has a root and a head opposite the
root. Each
U-spring has a pair of integrally-formed legs, each upper leaf spring is
integrally formed
at the root thereof with the upper sole, and each lower leaf spring is
integrally formed at
the root thereof with the tread layer. The leaf springs of each floating hinge
are integrally
joined at their respective heads to a respective one of the legs of the
associated U-spring.
According to another aspect of the invention, the leaf springs are configured
to resist the
compression by progressively straightening under the load.
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According to another aspect of the invention, the U-springs are configured to
resist the
compression by progressively compressing under the load.
According to another aspect of the invention, the U-springs are disposed
equidistantly
between the upper sole and the tread layer.
According to another aspect of the invention, the upper sole includes a toe
region and a
heel region, and each floating hinge has the U-spring oriented towards the toe
region.
According to another aspect of the invention, the mid-sole includes an
intervening
channel disposed between each adjacent pair of the floating hinges, and the
floating
hinges and the intervening channels extend continuously, without interruption,
across the
width of the sole.
According to another aspect of the invention, the leaf springs extend
transversely across
the entire width of the sole.
According to another aspect of the invention, the thickness of each leaf
spring is
substantially constant between the root and the head thereof.
According to another aspect of the invention, the thickness of each leaf
spring is
substantially constant across the entire width of the sole.
According to another aspect of the invention, the height of the floating
hinges is greater
proximate the heel region than the toe region.
In one implementation, the mid-sole comprises a resilient rubber roaterial.
In another implementation, the shoe upper and the outer sole of the foot
covering together
comprise a shoe,
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In another implementation, the shoe upper and the outer sole of the foot
covering togetber
coraprise a bodt.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described, by way of example, with reference to the
accompanying drawings, in vvhich.
Fig. 1 is a side elevation of a shoe having an outer sole, showing the upper
sole, the tread
layer and the resilient mid-sole;
Fig. 2 is a side elevation of the shoe depicted in Fig. 1, showing the mid-
sole compressed
under load;
Fig. 3 is a longitudinal cross-sectional view of the outer sole depicted in
Fig. 1, showing
the mid-sole in its undeformed state;
Fig. 4 is a longitudinal cross-sectional view of the outer sole, showing the
mid-sole
compressed under load;
Fig. 5 is a magnified cross-sectional view of the toe region of the outer
sole;
Fig. 6 is a magnified cross-sectional view of the heel region of the outer
sole;
Fig. 7 is a perspective view of the outer sole;
Fig. 8 is a side elevation of the outer sole; and
Fig. 9 is a rear elevation depicting the heel region of the outer sole.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIIVENTS
Turning to Fig. 1, an athletic or wallcing shoe 100 is shown comprising a
conventional
shoe upper 102, and an outer sole 200 secured to the shoe upper 102. The outer
sole 200
is secured to the shoe upper 102 in a conventional manner, such as with shoe
cement.
As shown in Fig. 3, the outer sole 200 includes a upper sole 202, a tread
layer 204
disposed below the upper sole 202, and a resilient mid-sole 206 disposed
between the
upper sole 202 and the tread layer 204. Preferably, the upper sole 202, the
read layer
204, and the mid-sole 206 are fabricated from a resilient rubber compound.
Further,
preferably the mid-sole 206 is integrally molded with the upper sole 202 and
the tread
layer 204.
The upper sole 202 has a toe region 208 proximate one end of the upper sole
202, and a
heel region 210 proximate the opposite end of the upper sole 202. In use, when
a human
foot is inserted into the shoe 100, between the shoe upper 102 and the outer
sole 200, the
toes of the foot will reside proximate the toe region 208, and the heel of the
foot will
reside proximate the heel region 210.
Preferably, the upper sole 202 is integrally molded with the tread layer 204
proximate the
toe region 208, but is only coupled to the tread layer 204 at the heel region
210 via the
mid-sole 206 and a flexible U-shaped hinge 226 that protrudes rearwardly from
the outer
sole 200. As will become apparent, this arrangement allows the upper sole 202
to move
Yertically relative to the tread layer 204, at the heel region 210, when the
outer sole 200 is
under load to thereby provide vertical cushioning to the foot.
Preferably, the tread layer 204 includes several substantially parallel
resilient ribs 212
that serve to increase the traction of the shoe 100. Each rib 212 extends
downr+vardly
away from the upper sole 202, transversely across the width of the tread layer
204.
The resilient mid-sole 206 includes at least one floating hinge 214 that is
oriented
transversely to the longitudinal axis of the outer sole 200. Preferably, the
resilient mid-
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sole 206 includes several such floating hinges 214 disposed along the entire
length of the
outer sole 200. As will be come apparent, the floating hinges 21.4 conflgure
the mid-sole
206 to resist compression when the outer sole 200 is under load.
As shown, each floating hinge 214 comprises an upper resilient leaf spring
216, a lower
resilient leaf spring 218, and a U-spring 220 that joins the leaf springs 216,
218 together.
The upper leaf spring 216 has a root portion 216a, and a head portion 216b
opposite the
root portion 216a. Each upper leaf spring 216 is integrally formed with the
upper sole
202 at the root portion 216a. Similarly, the lower leaf spring 218 has a root
portion 218a,
and a head portion 218b opposite the root portion 218a. Each lower leaf spring
218 is
integrally formed with the tread layer 204 at the root portion 218a.
As shown, the leaf springs 216, 218 each have a convex profile, with the
radius of
curvature of each leaf spring 216, 218 being greater proximate the root
portion 216a,
218a than the head portion 216b, 218b. However, the profite of each upper leaf
spring
216 is opposite to the profile of each lower leaf spring 218.
The leaf springs 216, 218 extend transversely across the outer sole 200,
preferably across
the entire width of the outer sole 200. Preferably, the thickness of each leaf
spring 216,
218 is substantially constant between the root portion 216a, 218a and the head
portion
216b, 218b, and is substantially constant across the entire width of the outer
sole 200.
In addition, preferably the mid-sole 206 includes an intervening channel 222
d.isposed
between each adjacent pair of the floating hinges 214, such that the floating
hinges 214
and the intervening channels 222 extend continuously, without interruption,
across the
width of the outer sole 200. Altettiately, one or more of the intervening
channels 222
may be filled with a resilient foam material to impart a desired resiliency to
the outer sole
200.
Each U-spring 220 has a pair of integrally-connected legs 220a, 220b. One of
the legs
220a of each U-spring 220 is disposed above the other leg 220b of the same U-
spring
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220. Further, each leg 220a, 220b is substantially planar in cross-section,
and extends
transversely across the width of the outer sole 200. As shown, each U-spring
220
includes a channel 224, defined by the upper leg 220a and the lower leg 220b,
that
extends transversely across the width of the outer sole 200, and separates the
upper leg
S 220a from the lower leg 220b when the outer sole 200 is not under load.
The upper leaf spring 216 of each floating hinge 214 is integrally formed with
the upper
leg 220a of the associated U-spring 220 at the head portion 216b. Similarly,
the lower
leaf spring 218 of each floating hinge 214 is integrally formed with the lower
leg 220b of
the associated U-spring 220 at the head portion 218b.
Preferably, the leaf springs 216, 218 have substantially the same length and
curvature,
and the U-springs 220 are disposed equidistantly between the upper sole 202
and the
tread layer 204. Further, preferably the floating hinges 214 are oriented such
that the U-
springs 220 are oriented towards the toe regiotl 208; and the root portions
216a, 218a of
the leaf springs 216, 218 are oriented towards the heel region 210.
As discussed above, the leaf springs 216, 218 axe resilient in nature, and
have opposing
convex profiles. Therefore, as the vertical load on the outer sole 200
increases (eg. due to
wearer of the shoe 100 taking a step), the leaf springs 216, 218 will resist
vertical
compression of the outer sole 200 by progressively straightening under the
load.
Due to the varying radius of curvature of the leaf springs 216, 218 (as
discussed above),
the head portions 216a, 218a of the leaf springs 216, 218 will deflect from
their unloaded
shape more readily under vertical load (eg. under the weight of the wearer of
the shoe
100) than the root portions 216b, 218b. As the vertical load on the outer sole
200
increases, the head portions 216a, 218a of the leaf springs 216, 218 will abut
each other
(as shown in Figs. 2 and 4), thereby preventing further deformation of the
leaf spri.ngs
216, 218 at the head portions 216a, 218a. However, the root pdrtions 216b,
218b of the
leaf springs 216, 218 will then begin to deflect from their unloaded shape. As
a result,
the leaf springs 216, 218 provide progressive vertical cushioning to the foot.
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Preferably, each U-spring 220 is resilient, but is more resilient than the
leaf springs 216,
218. Therefore, upon initial application of the verticalload, the U-springs
220 will resist
compression of the outer sole 20 first, followed subsequently by deformation
of the leaf
springs 216, 218. As a result, with this latter configuration, more
progressive vertical,
cushioning can be provided to the foot.
Also, preferably the height of the floating hinges 214 is greater proximate
the heel 210
region than the toe region 208 to -provide increased cushioning to the heel of
the foot.
However, the outer sole 200 may have an alternate cross-sectional profile, for
enhanced
load distribution. For instance, the height of the floating hinges 214 may be
greater
adjacent the areas of the sole 200 that coincide with the maximum load points
of the foot,
such as the ball and heel of the foot, to provide enhanced support for these
regions of the
foot.
Numerous variations on the foregoing embodiment are contemplated herein. For
instance, typically the mid-sole 206 is modular, in the sense that the
thickness and size of
all the leaf springs 216, 218 are substantially the same. As a result, a
desired amount of
vertical cushioning can be obtained by increasing or decreasing the thickness
and/or size
of all the leaf springs 216, 218. Alternately, however, the thickness and/or
size of
individual leaf springs 216, 218 can be increased or decreased to provide
selective
vertical cushioning at specified locations along the outer sole 200. Further,
the amount of
vertical cushioning can be adjusted by the appropriate selection of the
material from
which the leaf springs 216, 218 are constructed.
Also, the nurnber of floating hinges 214 per unit length (density) of the mid-
sole 206 may
be selected to provide a different amount of cushioning to the foot. This
density variation
may be implemented by either increasing or reducing the size of the
intervening channels
222 andlor by increasing or reducing the length and/or angle of incline of the
leaf springs
216, 218. Further, the density (as defined above) of the floating hinges 214
need not be
tutiform, but instead may vary along the length of the sole 200. For instance,
the density
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of the floating hinges 214 may be greater adjacent the areas of the sole 200
that coincide
with the ball and heel of the foot, and may be lower adjacent the areas of the
sole 200 that
coincide with the arch of the foot.
Further, as discussed above, typically the thickness of each leaf spring 216,
218 is
substantially constant between the root portion 216a, 218a and the head
portion 216b,
218b, and is substantially constant across the entire width of the outer sole
200.
Alternately, however, the thickness of each leaf spring 216, 218 may vary
between the
root portion 216a, 218a and the head portion 216b, 218b to provide a different
progressive vertical cushioning profile.
The foregoing description is illustrative of the preferred embodiment of the
invention,
with the claims appended hereto defining the intended scope of the monopoly
for the
invention. Those of ordinary skill will envisage certain modifications to the
described
embodiment which, although not explicitly suggested therein, do not depart
from the
scope of the invention, as defined by the appended claims.
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