OUTER SOLE HAVING RESILIENT MID-SOLE WITH FLOATING HINGES

Abstract

An outer sole includes an upper sole, a tread layer disposed below the upper sole, and a resilient mid-sol disposed between the upper sole and the tread layer. The mid-sole resists compression under load, and 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 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 heads to one of the legs of the associated U-spring.

Description

FIELD 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 (U.S. Pat. No. 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 (U.S. Pat. No. 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 impact with the ground.

Cohen (U.S. Pat. No. 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 similar 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.

Diaz (U.S. Pat. No. 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 (U.S. Pat. No. 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 2 297 768) 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 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 INVENTION

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 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, 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 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 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.

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 material.

In another implementation, the shoe upper and the outer sole of the foot covering together comprise a shoe.

In another implementation, the shoe upper and the outer sole of the foot covering together comprise a boot.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

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.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning to FIG. 1, an athletic or walking 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 vertically 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 downwardly 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-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 214 configure 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 profile 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 disposed 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. Alternately, 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 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 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 region 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 are 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 springs 216, 218 at the head portions 216a, 218a. However, the root portions 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.

Preferably, each U-spring 220 is resilient, but is more resilient than the leaf springs 216, 218. Therefore, upon initial application of the vertical load, 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 number 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 and/or 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 uniform, but instead may vary along the length of the sole 200. For instance, the density 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.

Claims

1. An outer sole comprising: an upper sole;a tread layer disposed below the upper sole; anda resilient mid-sole disposed between the upper sole and the tread layer and being configured to resist compression under load, the mid-sole comprising at least one floating hinge extending transversely to a longitudinal axis of the sole, each said floating hinge including an upper resilient convex leaf spring, a lower resilient convex leaf spring, and a U-spring joining the leaf springs together, each said leaf spring having a root and a head opposite the root, each said U-spring having a pair of integrally-formed legs, each said upper leaf spring being integrally formed at the root thereof with the upper sole, each said lower leaf spring being integrally formed at the root thereof with the tread layer, the leaf springs of each said floating hinge being integrally joined at their respective heads to a respective one of the legs of the associated U-spring.

2. The outer sole according to claim 1, wherein the leaf springs are configured to resist the compression by progressively straightening under the load.

3. The outer sole according to claim 2, wherein the U-springs are configured to resist the compression by progressively compressing under the load.

4. The outer sole according to claim 3, wherein the U-springs are disposed equidistantly between the upper sole and the tread layer.

5. The outer sole according to claim 4, wherein the upper sole includes a toe region and a heel region, and each said floating hinge has the U-spring oriented towards the toe region.

6. The outer sole according to claim 5, wherein the mid-sole includes an intervening channel disposed between each adjacent pair of the floating hinges, the floating hinges and the intervening channels each extending continuously, without interruption, across a width of the sole.

7. The outer sole according to claim 6, wherein the mid-sole includes a resilient foam disposed within the channels.

8. The outer sole according to claim 7, wherein the leaf springs extend transversely across the entire width of the sole.

9. The outer sole according to claim 8, wherein a thickness of each said leaf spring is substantially constant between the root and the head thereof.

10. The outer sole according to claim 8, wherein a thickness of each said leaf spring varies between the root and the head thereof.

11. The outer sole according to claim 9, wherein the thickness of each said leaf spring is substantially constant across the entire width of the sole.

12. The outer sole according to claim 11, wherein the height of the floating hinges is greater proximate the heel region than the toe region.

13. The outer sole according to claim 12, wherein the mid-sole comprises a resilient rubber material.

14. A foot covering comprising: a shoe upper; andan outer sole secured to the shoe, upper, the outer sole being configured according to any one of claims 1 to 13.

15. The foot covering according to claim 14, wherein the shoe upper and the outer sole together comprise a shoe.

16. The foot covering according to claim 15, wherein the shoe upper and the outer sole together comprise a boot.