Patent Application
20070251122
1. Field of the Invention
Embodiments of the present invention generally relate to a cushioning member, and more particularly relate to a cushioning member for use in an article of footwear.
2. Background Art
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, as well as the collapsibility of the arch, help to cushion the foot. 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.
Although the human foot possesses natural cushioning and rebounding characteristics, the foot may need extra support to overcome many of the forces encountered during extended periods of activity. Unless an individual is wearing shoes which provide proper cushioning and support, the soreness and fatigue resulting from even low levels of activity on unnatural surfaces is acute, and its onset accelerated. The discomfort for the wearer that results may diminish the incentive for further 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.
In light of these problems, numerous attempts have been made to incorporate improved cushioning and resiliency into a shoe. For example, a concept practiced in the footwear industry to improve cushioning and energy return has been the use of fluid-filled systems within shoe soles. These devices attempt to enhance cushioning and energy return by transferring a pressurized fluid between the heel and forefoot areas of a shoe. In addition, the design of the cushioning member may be an important marketing consideration.
Various embodiments of the present invention may provide improved cushioning to the wearer of an article of footwear. Some, but not necessarily all, embodiments of the present invention may provide a design, appearance, and/or visibility of the cushioning member so as to improve functionality and marketing considerations for the shoe incorporating the cushioning member. Additional advantages of embodiments of the present invention are set forth, in part, in the description which follows and, in part will be apparent to one of ordinary skill in the art from the description and/or from the practice of the invention.
Applicant has developed an innovative article of footwear. In one embodiment, the article of footwear comprises: a sole; and a cushioning member disposed in the sole, the cushioning member comprising: a substantially symmetrical u-shaped heel chamber having an anterior wall, a posterior wall, and medial and lateral sidewalls disposed between the anterior wall and the posterior wall; a forefoot chamber; and a passage connecting the heel chamber and the forefoot chamber, wherein the sole is formed around the cushioning member such that at least a portion of the medial heel sidewall and the lateral heel sidewall are visible.
Applicant has further developed an innovative cushioning member disposed in article of footwear having a sole. In one embodiment, the cushioning member comprises: a heel chamber having an anterior wall, a curved posterior wall, and medial and lateral sidewalls disposed between the anterior wall and the posterior wall; a forefoot chamber having an anterior wall, a posterior wall, and medial and lateral sidewalls disposed between the forefoot anterior wall and the forefoot posterior wall; and a passage connecting the heel chamber and the forefoot chamber, wherein the sole is formed around the cushioning member such that at least a portion of the medial heel sidewall and the lateral heel sidewall are visible and at least a portion of the forefoot chamber is visible.
Applicant has further developed a fluid-filled cushioning member disposed in an article of footwear having a sole, the cushioning member comprising: a substantially symmetrical u-shaped heel chamber having an anterior wall, a posterior wall, and medial and lateral sidewalls disposed between the anterior wall and the posterior wall; a forefoot chamber having an anterior wall, a posterior wall, and medial and lateral sidewalls disposed between the forefoot anterior wall and the forefoot posterior wall; and a passage connecting the heel chamber and the forefoot chamber, the passage comprising first and second air ports in communication with the forefoot chamber, and a depression formed between said first and second air ports, wherein the sole is formed around the cushioning member such that at least a portion of the heel chamber is visible and at least a portion of the forefoot chamber is visible.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed.
Reference will now be made in detail to embodiments of the present invention with reference to the accompanying figures, in which like reference numerals indicate like elements.
Referring now to
As shown in
It will be appreciated that the shoe upper 101 may comprise any material or design known to one of ordinary skill in the art. Common materials used for the shoe upper 101 include leather, woven materials such as, for example, canvas, and synthetic materials such as, for example, vinyl.
In one embodiment, the sole 102 may comprise a midsole 103 and an outsole 104. The outsole 104 is preferably constructed of a resilient, durable material such as, for example, rubber. The outsole 104 is intended to provide traction as the ground-engaging surface of the shoe 100. In the embodiment of the present invention shown in
The midsole 103 provides structure to the sole 102, as well as additional padding between a wearer's foot and the ground. The midsole 103 may be constructed of a material that is less dense than that used for the outsole 104, so that the thickness of the sole 102 may be increased without significantly increasing the weight of the shoe 100. In a preferred embodiment of the present invention, the midsole 103 comprises ethyl vinyl acetate (EVA). Other materials appropriate for the midsole 103 including, but not limited to, polyurethane (PU), thermoplastic urethane (TPU), and thermoplastic rubber (TPR) are considered to be within the scope of the present invention.
A first embodiment of the cushioning member 200 is shown with reference to
The cushioning member 200 is preferably a single member having three discrete components. As shown with reference to
The forefoot chamber 230 is disposed opposite the heel chamber 210 and beneath a portion of the forefoot or metatarsal area of a wearer when incorporated within the shoe 100. In the embodiment shown in
The cushioning member 200 is a hollow structure preferably filled with a fluid. In one embodiment of the present invention, the fluid may comprise a pressurized gas. In one embodiment of the present invention, the cushioning member 200 is filled with Nitrogen (N2). Nitrogen gas may provide a clean, readily available, and/or stable gas that may be less susceptible to pressure and/or temperature drops. Other gases, including, but not limited to, sulfur hexafluoride (SF6) may be suitable for use within the cushioning member 200 without departing from the scope and spirit of the claimed invention. The cushioning member 200 may be impermeable to air such that it is not possible for the gas disposed inside the cushioning member 200 to escape upon application of force to the cushioning member 200. It is appreciated, however, that gas may diffuse in and out of the cushioning member 200 under normal operating conditions. The cushioning member 200 may retain its cushioning properties throughout the life of the article of footwear in which it is incorporated. In an alternative embodiment of the present invention, the fluid may comprise ambient air.
The fluid passage 220 provides fluid communication between the heel chamber 210 and the forefoot chamber 230. In one embodiment, as shown in
With reference to
A depression 223 may be formed in the cushioning member 200 between the first 221 and second 222 fluid ports of the fluid passage 220. The depression 223 may be formed such that no fluid flows through or is stored within the depression 223. When the cushioning member 200 is provided in the shoe 100, the depression 223 is preferably located beneath the metatarsal arch of the wearer. The metatarsal arch can be a sensitive area of the foot, and the sensation caused by the flow of fluid beneath this area can provide discomfort to the wearer. Because there is no fluid flow within the depression 223, the depression 223 may provide improved comfort to the wearer. The depression 223 may also provide a convenient portion of the cushioning member 200 to present data relating to the cushioning member, such as, for example, manufacturing information, and patent marking.
With reference to
In an alternative embodiment of the present invention, the cushioning member 200 may be disposed in a cavity formed in the midsole 103. The cavity may be formed on the top of the midsole 103, or between the bottom of the midsole and the outsole 104. The cushioning member 200 may be attached to the midsole 103 with adhesive material such as cement or the like. In another embodiment of the present invention, an upper midsole portion comprising a material different from the rest of the midsole 103, such as, for example, polyurethane wherein the rest of the midsole 103 may comprise EVA, may first be molded directly to all or a portion of the cushioning member 200. The upper midsole portion and the cushioning member 200 may then be cemented into a cavity formed in the midsole 103.
In various embodiments of the present invention, the visibility of the cushioning member 200 may be of particular importance to the design of the shoe 100. The sole 102 may be formed around the cushioning member 200 such that at least a portion of the heel chamber 210 of the cushioning member 200 is visible. With reference to
With reference to
With reference to
The cushioning member 200 is preferably formed via extrusion blow molding. As will be apparent to those of ordinary skill in the art, the cushioning member 200 may be formed during the blow molding process such that a unitary member is formed and each of the three discrete components described herein is formed using the same mold. The cushioning member 200 is preferably formed of a suitably resilient material so as to allow the cushioning member 200 to compress and expand while also resisting breakdown. In one embodiment, the cushioning member 200 may comprise a highly crystalline Thermoplastic Urethane (TPU). Other materials, including, but not limited to, EVA, thermoplastics, and/or other suitably resilient materials may be used without departing from the scope and spirit of the present invention.
Operation of the first embodiment of the present invention will now be described. When stationary, the foot of the wearer is adequately cushioned by the cushioning member 200, and substantially no air flows through the fluid passage 220 from the heel chamber 210 to the forefoot chamber 230. 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. At this point, the heel area of the shoe 100 contacts the ground or other support surface first, and the weight of the wearer applies downward pressure on the heel chamber 210, causing the chamber to compress. The compression of the heel chamber 210 causes fluid in the chamber to be forced forwardly, through the fluid passage 220 and the first 221 and second 222 fluid ports to the forefoot chamber 230. The flow of fluid into the forefoot chamber 230 causes the forefoot chamber to expand.
As the gait cycle continues, the distribution of forces on the foot moves toward the center axis of the foot in the arch area at mid-stride, rolls medially and then shifts to the center axis of the foot again during “toe-off.” When the forefoot of the wearer contacts the ground, the expanded forefoot chamber 230 provides cushioning from the related impact forces. As the weight of the wearer is applied to the forefoot, the downward pressure caused by the impact forces causes the forefoot chamber 230 to compress, forcing the air therein to be thrust rearwardly through the fluid passage 220 into the heel chamber 210. It is noted that the weld lines 216 prevent over expansion of the heel chamber 210 which could cause discomfort to the wearer. After “toe-off,” no downward pressure is applied to the cushioning member 200, so the air within the member returns to its unloaded state. The gait cycle is then repeated. In this manner, the cushioning member 200 may provide cushioning to a wearer of the shoe 100 such that the wearer's stride forces air within the cushioning member 200 to move in a complementary manner with respect to the stride.
A second embodiment of the cushioning member 200 of the present invention is shown in
The forefoot chamber 1330 is disposed opposite the heel chamber 1310 and beneath a portion of the forefoot or metatarsal area of a wearer when incorporated within the shoe 100. The forefoot chamber 1330 includes a posterior wall 1331, and an anterior wall 1332. A medial sidewall 1333, and a lateral sidewall 1334 are disposed between the posterior wall 1331 and the anterior wall 1332.
The cushioning member 200 may further comprise means for controlling the flow of fluid within the cushioning member. In one embodiment, the cushioning member 200 may include one or more weld lines 1316 formed in the heel chamber 1310 and the forefoot chamber 1330, and one or more spot welds 1325 formed in the forefoot chamber 1330. The weld lines 1316 and the spot welds 1325 may be positioned such that the heel chamber 1310 and/or the forefoot chamber 1330 of the cushioning member 200 do not over expand with fluid or balloon during operation. For example, in one embodiment a plurality of weld lines 1316 may be formed around the perimeter of the heel chamber 1310 and may prevent the flow of fluid into the heel chamber from causing the heel chamber 1310 to over expand. In one embodiment, weld lines also may be formed in the medial and lateral side of the forefoot chamber 1330. In addition, a plurality of spot welds 1325 may be formed in a triangular arrangement in the center of the forefoot chamber 1330 and may prevent the flow of fluid into the forefoot chamber from causing the forefoot chamber 1330 to over expand. The precise number, size, shape, and location of the spot welds 1325 and the weld lines 1316 shown is intended to be exemplary only. It is contemplated that other configurations of the weld lines 1316 and the spot welds 1325 may be provided without departing from the scope of the present invention.
The sole 102 may be formed around the cushioning member 200 such that at least a portion of the forefoot chamber 1330 of the cushioning member 200 is visible. With reference to
A third embodiment of the cushioning member 200 of the present invention is shown in
In one embodiment, as shown in
With reference to
The manner of inflating the cushioning member 200 of various embodiments of the present invention will now briefly be described. In embodiments of the present invention in which the cushioning member 200 is filled with pressurized gas, the cushioning member 200 may be filled with gas at a pressure that provides a suitable level of cushioning and fluid flow. As will be apparent to those of ordinary skill in the art, a tube (not shown) may be formed in the cushioning member for receiving an air hose. The air hose may be attached to the tube and the cushioning member may be pressurized to a predetermined level. When the desired pressure is reached, the tube may be heat sealed to prevent leakage from the cushioning member.
At higher pressures, there is generally more fluid filling the cushioning member, and the cushioning member experiences less compression during operation. As a result, a cushioning member filled at too high a pressure may create a hard and uncomfortable feeling underneath the foot of the wearer. At lower pressures, there may be increased fluid flow within the cushioning member, and increased “pistoning” of the wearer's foot inside the shoe. As a result, a cushioning member filled at too low a pressure may provide less cushioning, and the resulting increased movement of the foot may lead to blistering. In addition, too much flow of fluid may create a sensation beneath the foot of the wearer that can cause discomfort. Thus, it is important that the proper balance of fluid pressure within the cushioning member 200 be reached.
Each of the embodiments of the present invention may be pressurized to different pressure ranges such that the cushioning members provide preferred levels of cushioning and fluid flow. For example, the first embodiment of the cushioning member 200 shown in
While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the present invention. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents. All patents and publications discussed herein are incorporated in their entirety by reference thereto.
