Support and cushioning system for an article of footwear Number:7,181,867 from the United States Patent and Trademark Office (PTO) owispatent A cushioning member for an article of footwear. The cushioning member is a flexible bladder having a fluidly interconnected heel chamber and forefoot chamber. The bladder is disposed above the sole and beneath the wearer's foot to provided added cushioning to the wearer. The bladder contains air at slightly above ambient pressure and can be formed by thermoforming or by welding two sheets of resilient, flexible material together. A connecting passage fluidly connects the heel chamber and the forefoot chamber. The connecting passage is narrow to control the flow of air between the two chambers.<H cushioning, footwear, Support, and, cus, 7181867.html, Patent, pto, 7181867

Title: Support and cushioning system for an article of footwear

Abstract: A cushioning member for an article of footwear. The cushioning member is a flexible bladder having a fluidly interconnected heel chamber and forefoot chamber. The bladder is disposed above the sole and beneath the wearer's foot to provided added cushioning to the wearer. The bladder contains air at slightly above ambient pressure and can be formed by thermoforming or by welding two sheets of resilient, flexible material together. A connecting passage fluidly connects the heel chamber and the forefoot chamber. The connecting passage is narrow to control the flow of air between the two chambers.

Patent Number: 7,181,867 Issued on 02/27/2007 to Litchfield, et al.

Inventors: Litchfield; Paul E. (Westborough, MA), Montross; Matthew J. (Quincy, MA), Smith; Steven F. (Taunton, MA), White; J. Spencer (N. Easton, MA), Jessiman; Alexander W. (Scituate, MA)
Assignee: Reebok International Ltd. (Canton, MA)

Appl. No.: 11/041,225

Filed: January 25, 2005

Related U.S. Patent Documents


Application Number	Filing Date	Patent Number	Issue Date
10243825	Jan., 2005	6845573
09314893	Sep., 2002	6453577
09042078	Mar., 1998
08697895	Jun., 1998	5771606
08599100	Feb., 1996
08284646
PCT/US94/00895	Jan., 1994

Current U.S. Class: 36/29 ; 36/141; 36/153; 36/35B; 36/44

Current International Class: A43B 13/20 (20060101); A43B 13/40 (20060101); A43B 7/14 (20060101); A61F 5/14 (20060101)

Field of Search: 36/28,29,3B,71,141,44,153,35B

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Primary Examiner: Mohandesi; Jila M
Attorney, Agent or Firm: Sterne, Kessler, Goldstein & Fox P.L.L.C.

Parent Case Text

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No. 10/243,825, filed Sept. 16, 2002, now U.S. Pat. No. 6,845,573 issued Jan. 25, 2005 ; which is a continuation of U.S. application Ser. No. 09/314,893, filed May 19, 1999, now U.S. Pat. No. 6,453,577, issued Sept. 24, 2002; which is a continuation of U.S. application Ser. No. 09/042,078, filed Mar. 13, 1998, now abandoned; which is a continuation of U.S. application Ser. No. 08/697,895, filed Sept. 3, 1996, now U.S. Pat. No. 5,771,606, issued Jun. 30, 1998; which is a continuation-in-part of U.S. application Ser. No. 08/599,100, filed Feb. 9, 1996, now abandoned; which is a continuation of U.S. application Ser. No. 08/284,646, filed Oct. 14, 1994, now abandoned; which is National Stage of GC Application No. PCT/US594/00895, filed Jan. 26, 1994.

Claims

What is claimed is:

1. An article of footwear comprising: a sole having a heel portion divided between a medial region and lateral region, and having a resilient insert and an outsole disposed below said resilient insert; said resilient insert having a plurality of compressible support elements disposed in the heel portion, wherein only two support elements are entirely disposed in the medial region of the heel portion, and at least one support element is entirely disposed in the lateral region of the heel portion; wherein the at least one support element entirely disposed in the lateral region of the heel portion has a volume which differs from the volume of at least one other chamber which at least a portion of which is disposed within the lateral region of the heel portion.

2. The article of footwear of claim 1, wherein at least one support element is disposed partially within the medial region and partially within the lateral region of the heel portion.

3. The article of footwear of claim 1, wherein at least one support element includes a curved upper surface which curves downward toward a center of the heel portion.

4. The article of footwear of claim 1, wherein the support elements are surrounded by a foam material.

5. The article of footwear of claim 1, wherein the support elements comprise fluid filled chambers.

6. The article of footwear of claim 1, wherein the support elements are interconnected.

7. The article of footwear of claim 1, including at least four support elements forming a quadrilateral arrangement in the heel portion.

8. The article of footwear of claim 1, wherein the sole further comprises a forefoot portion, and the resilient insert further comprises a plurality of compressible support elements disposed within the forefoot portion.

9. The article of footwear of claim 1, further comprising: a midsole; wherein the resilient insert is disposed between the midsole and the outsole.

10. The article of footwear of claim 1, further comprising: a cavity; wherein the resilient insert is disposed within the cavity.

11. An article of footwear comprising: a sole having a heel portion divided between a medial region and a lateral region, and having a resilient insert and an outsole disposed below the resilient insert; said resilient insert having a plurality of compressible support elements, wherein only two support elements are entirely disposed in the medial region of the heel portion, and at least two chambers are entirely disposed in the lateral region of the heel portion; wherein at least one support element includes an upper surface, and wherein at least a portion of the upper surface curves downward toward a center of the heel portion.

12. The article of footwear of claim 11, wherein at least one support element is larger than at least one other support element.

13. The article of footwear of claim 11, wherein the at least one support element entirely disposed in the lateral region has a volume which differs from at least one other support element.

14. An article of footwear comprising: an upper; a midsole attached to the upper; an outsole disposed below the midsole; and a resilient insert having at least four compressible support elements disposed between the midsole and the outsole, wherein only two support elements are entirely disposed in a medial region of a heel portion of the article of footwear, at least one support element is entirely disposed in a lateral region of the heel portion, wherein at least one support element is hollow, and wherein the at least one support element entirely disposed in the lateral region has a volume which differs from the volume of another chamber which at least a portion of which is disposed in the lateral region.

15. An article of footwear having a medial side and a lateral side, comprising: a sole having a heel portion, and having a resilient insert and an outsole disposed below said resilient insert; said resilient insert having a plurality of support elements disposed in the heel portion of the sole, wherein: a first support element is disposed in a posterior area of the heel portion and on the lateral side of the footwear, a second support element is disposed forward of the first support element, a third support element is disposed in a posterior area of the heel portion and on the medial side of the footwear, and a fourth support element is disposed forward of the third support element; wherein only the first and second support elements are entirely disposed on the lateral side of the footwear and only the third and fourth support elements are entirely disposed on the medial side of the footwear; and wherein at least one support element has an upper surface, wherein a portion of the upper surface curves downward toward a center of the heel portion.

16. The article of footwear of claim 15, further comprising a fifth support element disposed in the heel portion of the sole.

17. The article of footwear of claim 15, wherein at least one of the support elements is larger than at least one other support element.

18. The article of footwear of claim 15, wherein the first support element is larger than at least one other support element.

19. An article of footwear comprising: a sole having a heel portion divided between a medial region and a lateral region, and having a resilient insert having only five compressible support elements disposed within the heel portion, wherein two support elements are entirely disposed in the medial region of the heel portion, two support elements are entirely disposed in the lateral region of the heel portion, and one support element is partially disposed within the lateral region and partially disposed within the medial region, wherein the one support element disposed partially within the lateral region and partially within the medial region has a volume which differs from at least one other support element.

20. The article of footwear of claim 19, wherein the resilient insert is surrounded by a foam material.

21. The article of footwear of claim 19, wherein the support element disposed partially within the lateral region and partially within the medial region has a flattened upper surface.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to footwear, and more particularly to an article of footwear having a system for providing cushioning and support for the comfort of the wearer.

2. Related Art

One of the problems associated with shoes has always been striking a balance between support and cushioning. Throughout the course of an average day, the feet and legs of an individual are subjected to substantial impact forces. Running, jumping, walking and even standing exert forces upon the feet and legs of an individual which can lead to soreness, fatigue, and injury.

The human foot is a complex and remarkable piece of machinery, capable of withstanding and dissipating many impact forces. The natural padding of fat at the heel and forefoot, as well as the flexibility of the arch, help to cushion the foot. An athlete's stride is partly the result of energy which is stored in the flexible tissues of the foot. For example, during a typical walking or running stride, the achilles tendon and the arch stretch and contract, storing energy in the tendons and ligaments. When the restrictive pressure on these elements is released, the stored energy is also released, thereby reducing the burden which must be assumed by the muscles.

Although the human foot possesses natural cushioning and rebounding characteristics, the foot alone is incapable of effectively overcoming many of the forces encountered during athletic activity. Unless an individual is wearing shoes which provide proper cushioning and support, the soreness and fatigue associated with athletic activity is more acute, and its onset accelerated. This results in discomfort for the wearer which diminishes the incentive for further athletic activity. Equally important, inadequately cushioned footwear can lead to injuries such as blisters, muscle, tendon and ligament damage, and bone stress fractures. Improper footwear can also lead to other ailments, including back pain.

Proper footwear should complement the natural functionality of the foot, in part by incorporating a sole (typically, an outsole, midsole and insole) which absorbs shocks. However, the sole should also possess enough resiliency to prevent the sole from being "mushy" or "collapsing," thereby unduly draining the energy of the wearer.

In light of the above, numerous attempts have been made over the years to incorporate into a shoe means for providing improved cushioning and resiliency to the shoe. For example, attempts have been made to enhance the natural elasticity and energy return of the foot by providing shoes with soles which store energy during compression and return energy during expansion. These attempts have included using compounds such as ethylene vinyl acetate (EVA) or polyurethane (PU) to form midsoles. However, foams such as EVA tend to break down over time, thereby losing their resiliency.

Another concept practiced in the footwear industry to improve cushioning and energy return has been the use of fluid-filled devices within shoes. These devices attempt to enhance cushioning and energy return by transferring a pressurized fluid between the heel and forefoot areas of a shoe. The basic concept of these devices is to have cushions containing pressurized fluid disposed adjacent the heel and forefoot areas of a shoe. The overriding problem of these devices is that the cushioning means are inflated with a pressurized gas which is forced into the cushioning means, usually through a valve accessible from the exterior of the shoe.

There are several difficulties associated with using a pressurized fluid within a cushioning device. Most notably, it may be inconvenient and tedious to constantly adjust the pressure or introduce a fluid to the cushioning device. Moreover, it is difficult to provide a consistent pressure within the device thereby giving a consistent performance of the shoes. In addition, a cushioning device which is capable of holding pressurized gas is comparatively expensive to manufacture. Further, pressurized gas tends to escape from such a cushioning device, requiring the introduction of additional gas. Finally, a valve which is visible to the exterior of the shoe negatively affects the aesthetics of the shoe, and increases the probability of the valve being damaged when the shoe is worn.

A cushioning device which, when unloaded contains air at ambient pressure provides several benefits over similar devices containing pressurized fluid. For example, generally a cushioning device which contains air at ambient pressure will not leak and lose air, because there is no pressure gradient in the resting state. The problem with many of these cushioning devices is that they are either too hard or too soft. A resilient member that is too hard may provide adequate support when exerting pressure on the member, such as when running. However, the resilient member will likely feel uncomfortable to the wearer when no force is exerted on the member, such as when standing. A resilient member that is too soft may feel cushy and comfortable to a wearer when no force is exerted on the member, such as when standing or during casual walking. However, the member will likely not provide the necessary support when force is exerted on the member, such as when running. Further, a resilient member that is too soft may actually drain energy from the wearer.

Accordingly, what is needed is a shoe which incorporates a cushioning system including a means to provide resilient support to the wearer during fast walking and running, and to provide adequate cushioning to the wearer during standing and casual walking.

SUMMARY OF THE INVENTION

To achieve the foregoing and other objects, and in accordance with the purposes of the present invention as embodied and broadly described herein, the article of footwear of the present invention comprises a sole and a resilient support and cushioning system. The system of the present invention includes a resilient insert member and a bladder disposed within an article of footwear.

In one embodiment, the resilient insert includes a plurality of heel chambers, a plurality of forefoot chambers and a central connecting passage fluidly interconnecting the chambers. The resilient insert is preferably blow molded from an elastomeric material, and may contain air at ambient pressure or slightly above ambient pressure. The resilient insert is placed between an outsole and a midsole of the article of footwear.

In one embodiment, the central connecting passage contains an impedance mean to restrict the flow of air between the heel chambers and the forefoot chambers. Thus, during heel strike, the air is prevented from rushing out of the heel chambers all at once. Thus, the air in the heel chambers provides support and cushioning to the wearer's foot during heel strike.

The bladder of the present invention includes a heel chamber, a forefoot chamber and at least one connecting passage fluidly interconnecting the two chambers. The bladder is disposed above the midsole of the article of footwear, and provides added cushioning to the wearer's foot. In one embodiment, the bladder is thermoformed from two sheets of resilient, non-permeable elastomeric material such that the bladder contains air at slightly above ambient pressure.

In use, the bladder provides cushioning to the wearer's foot while standing or during casual walking. The resilient insert provides added support and cushioning to the wearer's foot during fast walking and running. In an alternate embodiment, for example, for use as a high performance shoe, the article of footwear may contain only the resilient insert disposed between the midsole and outsole. In another alternate embodiment, for example, for use as a casual shoe, the article of footwear may contain only the bladder disposed above the midsole.

When stationary, the foot of a wearer is cushioned by the bladder. When the wearer begins a stride, the heel of the wearer's foot typically impacts the ground first. At this time, the weight of the wearer applies downward pressure on the heel portion of the resilient insert, causing the heel chambers to be forced downwardly.

The heel chambers of the resilient insert are connected via periphery passages. These passages essentially divide the heel portion into a medial region and a lateral region so that the resilient insert is designed geometrically to help compensate for the problem of pronation, the natural tendency of the foot to roll inwardly after heel impact. During a typical gait cycle, the main distribution of forces on the foot begins adjacent the lateral side of the heel during the "heel strike" phase of the gait, then moves toward the center axis of the foot in the arch area, and then moves to the medial side of the forefoot area during "toe-off." The configuration of the passages between the heel chambers ensures that the air flow within the resilient insert complements such a gait cycle.

Thus, the downward pressure resulting from heel strike causes air within the resilient insert to flow from the medial region into the lateral region. Thus, the medial region is cushioned first to prevent the wearer's foot from rolling inwardly. Further compression of the heel portion causes the air in the lateral region to be forced forwardly, through the central connecting passage and into the forefoot portion of the resilient insert.

The flow of air into the forefoot portion causes the forefoot chambers to expand, which slightly raises the forefoot or metatarsal area of the foot. When the forefoot of the wearer is placed upon the ground, the expanded forefoot chambers help cushion the corresponding impact forces. As the weight of the wearer is applied to the forefoot, the downward pressure caused by the impact forces causes the forefoot chambers to compress, forcing the air therein to be thrust rearwardly through the central connecting passage into the heel portion.

After "toe-off," no downward pressure is being applied to the article of footwear, so the air within the resilient insert should return to its normal state. Upon the next heel strike, the process is repeated.

In light of the foregoing, it will be understood that the system of the present invention provides a variable, non-static cushioning, in that the flow of air within the bladder and the resilient insert complements the natural biodynamics of an individual's gait.

BRIEF DESCRIPTION OF THE FIGURES

The foregoing and other features and advantages of the invention will be apparent from the following, more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings.

FIG. 1 is a top plan view of a resilient insert in accordance with the present invention.

FIG. 2 is a medial side view of the resilient insert of FIG. 1.

FIG. 3 is a cross-sectional view taken along line 3--3 of FIG. 1.

FIG. 4 is a cross-sectional view taken along line 4--4 of FIG. 1.

FIG. 5 is a cross-sectional view taken along line 5--5 of FIG. 1.

FIG. 6 is an exploded view of one possible interrelationship of an outsole, resilient insert and midsole in accordance with the present invention.

FIG. 7 is a cross-sectional view taken along line 7--7 of FIG. 6.

FIG. 8 is a bottom plan view of the outsole of the present invention, as shown in FIG. 6.

FIG. 9 is a bottom plan view of the midsole of the present invention, as shown in FIG. 6.

FIG. 10 is a top plan view of a bladder of the present invention.

FIG. 11 is a medial side view of the bladder of FIG. 10.

FIG. 12 is a cross-sectional view taken along line 12--12 of FIG. 10.

FIG. 13 is an exploded view of an alternate interrelationship of the outsole, resilient insert, midsole and bladder in accordance with the present invention.

FIG. 14 is a cross-sectional view taken along line 14--14 of FIG. 13.

FIG. 15 is a perspective view of a shoe of the present invention.

FIGS. 16 18 show alternate embodiments of bladders of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred embodiment of the present invention is now described with reference to the figures where like reference numbers indicate identical or functionally similar elements. Also in the figures, the left most digit of each reference number corresponds to the figure in which the reference number is first used. While specific configurations and arrangements are discussed, it should be understood that this is done for illustrative purposes only. A person skilled in the relevant art will recognize that other configurations and arrangements can be used without departing from the spirit and scope of the invention. It will be apparent to a person skilled in the relevant art that this invention can also be employed in a variety of other devices and applications.

Another cushioning device is described in U.S. patent application Ser. No. 08/599,100, filed Feb. 9, 1996, for a "Resilient Insert For An Article of Footwear," now pending, the disclosure of which is incorporated herein by reference, and which is a file wrapper continuation of U.S. patent application Ser. No. 08/284,646, filed Aug. 11, 1994, now abandoned, which claims priority under 35 U.S.C. .sctn. 119 to International Application Number PCT/US94/00895, filed Jan. 26, 1994.

Referring now to FIGS. 1 5, a resilient insert 102 is shown. Resilient insert 102 provides continuously modifying cushioning to an article of footwear, such that a wearer's stride forces air within resilient insert 102 to move in a complementary manner with respect to the stride.

FIG. 1 is a top plan view of resilient insert 102 in accordance with the present invention. However, FIG. 1 may in fact be either a top or bottom plan view, as the top and bottom of resilient insert 102 are substantially the same. FIG. 2 is a medial side view of resilient insert 102.

Resilient insert 102 is a three-dimensional structure formed of a suitably resilient material so as to allow resilient insert 102 to compress and expand while resisting breakdown. Preferably, resilient insert 102 may be formed from a thermoplastic elastomer or a thermoplastic olefin. Suitable materials used to form resilient insert 102 may include various ranges of the following physical properties:

TABLE-US-00001 Preferred Preferred Lower Upper Limit Limit Density (Specific Gravity in g/cm.sup.3) 0.80 1.35 Modulus @ 300% Elongation (psi) 1,000 6,500 Permanent Set @ 200% Strain (%) 0 55 Compression Set 22 hr/23.degree. C. 0 45 Hardness Shore A 70 -- Shore D 0 55 Tear Strength (KN/m) 60 600 Permanent Set at Break (%) 0 600

Many materials within the class of Thermoplastic Elastomers (TPEs) or Thermoplastic Olefins (TPOs) can be utilized to provide the above physical characteristics. Thermoplastic Vulcanates (such as SARLINK from PSM, SANTAPRENE from Monsanto and KRATON from Shell) are possible materials due to physical characteristics, processing and price. Further, Thermoplastic Urethanes (TPU's), including a TPU available from Dow Chemical Company under the tradename PELLETHANE (Stock No. 2355-95AE), a TPU available from B.F. Goodrich under the tradename ESTANE and a TPU available from BASF under the tradename ELASTOLLAN provide the physical characteristics described above. Additionally, resilient insert 102 can be formed from natural rubber compounds. However, these natural rubber compounds currently cannot be blow molded as described below.

The preferred method of manufacturing resilient insert 102 is via extrusion blow molding. It will be appreciated by those skilled in the art that the blow molding process is relatively simple and inexpensive. Further, each element of resilient insert 102 of the present invention is created during the same preferred molding process. This results in a unitary, "one-piece" resilient insert 102, wherein all the unique elements of resilient insert 102 discussed herein are accomplished using the same mold. Resilient insert 102 can be extrusion blow molded to create a unitary, "one-piece" component, by any one of the following extrusion blow molding techniques: needle or pin blow molding with subsequent sealing, air entrapped blow molding, pillow blow molding or frame blow molding. These blow molding techniques are known to those skilled in the relevant art.

Alternatively, other types of blow molding, such as injection blow molding and stretch blow molding may be used to form resilient insert 102. Further, other manufacturing methods can be used to form resilient insert 102, such as thermoforming and sealing, or vacuum forming and sealing.

Resilient insert 102 is a hollow structure preferably filled with ambient air. In one embodiment, resilient insert 102 is impermeable to air, i.e., hermetically sealed, such that it is not possible for the ambient air disposed therein to escape upon application of force to resilient insert 102. Naturally, diffusion may occur in and out of resilient insert 102. The unloaded pressure within resilient insert 102 is preferably equal to ambient pressure. Accordingly, resilient insert 102 retains its cushioning properties throughout the life of the article of footwear in which it is incorporated. If resilient insert 102 is formed by air entrapment extrusion blow molding, the air inside resilient insert 102 may be slightly higher than ambient pressure (e.g., between 1 5 psi above ambient pressure).

As can be seen with reference to FIG. 1, resilient insert 102 is preferably a unitary member comprising three distinct components: a heel portion 103, a forefoot portion 113, and a central connecting passage 124. Heel portion 103 is generally shaped to conform to the outline of the bottom of an individual's heel, and is disposed beneath the heel of a wearer when resilient insert 102 is incorporated within a shoe. In one embodiment, as shown in FIG. 1, heel portion 103 includes a plurality of peripheral heel chambers 104, 106, 108, 110 and a central heel air chamber 112.

Disposed opposite heel portion 103 is forefoot portion 113. Forefoot portion 113 is generally shaped to conform to the forefoot or metatarsal area of a foot, and is disposed beneath a portion of the forefoot of a wearer when incorporated within a shoe. In one embodiment, as shown in FIG. 1, forefoot portion 113 includes a plurality of peripheral forefoot chambers 114, 116, 118, 120 and a central forefoot air chamber 122. Preferably, the volume of air within the chambers of forefoot portion 113 is substantially the same as or slightly less than the volume of air within the chambers of heel portion 103.

As shown in FIG. 1, impedance means 126 and 128 are disposed within central connecting passage 124. Impedance means 126 and 128 provide a restriction in central connecting passage 124 to restrict the flow of air through central connecting passage 124. In one embodiment, impedance means 126 and 128 comprise a convolution of connecting passage 124 formed by restriction walls 129 (shown in detail in FIG. 4) placed in central connecting passage 124. In FIG. 1 impedance means 126 is shown as being substantially oval-shaped, and impedance means 128 is shown as being substantially circular. However, impedance means 126 and 128 may comprise numerous shapes or structures. For example, in another embodiment, the impedance means could be provided by a pinch-off of the material or increased wall thickness of the material.

Impedance means 126 and 128 prevent air from rushing out of heel chambers 104 112 upon heel strike wherein pressure is increased in heel portion 103. The shape or structure of impedance means 126 and 128 determines the amount of air that is permitted to pass through central connecting passage 124 at any given time.

The different structures of the impedance means of the present invention are accomplished during the preferred blow-molding manufacturing process described above. Accordingly, no complicated or expensive valve means need be attached to resilient insert 102. Rather, the shape of impedance means 126 and 128 is determined by the same mold used to form the remainder of resilient insert 102.

As noted above, the shape of impedance means 126 and 128 will affect the rate and character of air flow within resilient insert 102, in particular between heel portion 103 and forefoot portion 113 thereof.

Central connecting passage 124 comprises an elongated passage which connects heel portion 103 to forefoot portion 113. Central connecting passage 124 has a first branch 130, connected to forefoot air chamber 114, a second branch 132, connected to central forefoot air chamber 122, and a third branch 134, connected to forefoot air chamber 118. These separate branches 130 134 allow air to flow directly into forefoot portion 113