Boots – shoes – and leggings – Soles – Cushion
Reexamination Certificate
1999-10-20
2002-03-12
Yu, Mickey (Department: 3728)
Boots, shoes, and leggings
Soles
Cushion
C036S03500R, C036S00300B, C036S135000
Reexamination Certificate
active
06354020
ABSTRACT:
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 utilizing cushions containing pressurized fluid that are 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 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.
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 is disclosed in U.S. Pat. No. 5,771,606 to Litchfield et al., which is incorporated herein in its entirety by reference. U.S. Pat. No. 5,771,606 describes a resilient insert member including a plurality of heel chambers, a plurality of forefoot chambers and a central connecting passage fluidly interconnecting the chambers. The resilient insert is made from an elastomeric material and may contain air at ambient pressure. The resilient insert is placed between an outsole and a midsole of an article of footwear.
Although the resilient insert of U.S. Pat. No. 5,771,606 provides resilient support and adequate cushioning to the wearer during a wide range of activities, the arrangement and shape of the forefoot chambers results in a decrease in flexibility of the resilient insert about the metatarsal area of the foot. In addition, the shape, interconnection and placement of the heel chambers make the resilient insert somewhat rigid, such that substantial cushioning only occurs as to downward forces during heel strike.
Accordingly, what is needed is a shoe which incorporates a cushioning system including a means to provide resilient support and adequate cushioning to the wearer that anatomically compliments the wearer's foot so that flexibility is maintained and stability increased. In addition, the cushioning system must be more compliant during a wearer's gait thereby providing maximum support and cushioning benefit when downward and/or shear forces are applied.
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 one of the heel chambers with one of the forefoot chambers. The forefoot chambers are staggered and fluidly interconnected in series along either side of forefoot chamber interconnection passages. Each forefoot chamber is arranged so that a line taken lengthwise through each chamber is essentially perpendicular to a longitudinal centerline of the resilient insert.
The single central connecting passage and arrangement of the forefoot chambers i.e., their length extending in a lateral rather than a longitudinal direction, allow for a re
Bjornson Andrew A.
Jessiman Alexander W.
Kimball Neal F. X.
White J. Spencer
Moh'andesi Jila M.
Reebok International Ltd.
Sterne Kessler Goldstein & Fox P.L.L.C.
Yu Mickey
LandOfFree
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