Patent Application
20080163512
Conventional articles of athletic footwear include two primary elements, an upper and a sole structure. The upper is generally formed from a plurality of elements, such as textiles, foam, leather, and synthetic leather materials, that are stitched or adhesively bonded together to form an interior void for securely and comfortably receiving a foot. The sole structure incorporates multiple layers that are conventionally referred to as an insole, a midsole, and an outsole. The insole is a thin, compressible member located within the void of the upper and adjacent to a plantar (i.e., lower) surface of the foot to enhance comfort. The midsole is secured to the upper and forms a middle layer of the sole structure that attenuates ground reaction forces during walking, running, or other ambulatory activities. The outsole forms a ground-contacting element of the footwear and is usually fashioned from a durable and wear-resistant rubber material that includes texturing to impart traction.
The primary material forming many conventional midsoles is a polymer foam, such as polyurethane or ethylvinylacetate. In some articles of footwear, the midsole may also incorporate a sealed and fluid-filled chamber that increases durability of the footwear and enhances ground reaction force attenuation of the sole structure. In some footwear configurations, the fluid-filled chamber may be at least partially encapsulated within the polymer foam, as in U.S. Pat. No. 5,755,001 to Potter, et al., U.S. Pat. No. 6,837,951 to Rapaport, and U.S. Pat. No. 7,132,032 to Tawney, et al. In other footwear configurations, the fluid-filled chamber may substantially replace the polymer foam, as in U.S. Pat. No. 7,086,180 to Dojan, et al.
As an alternative to chambers, a footwear sole structure may also incorporate a fluid system that includes various components, such as a pressure chamber, a pump chamber for increasing a fluid pressure within the pressure chamber, one or more valves for regulating the direction and rate of fluid flow, and conduits that connect the various fluid system components. U.S. Pat. No. 6,457,262 to Swigart discloses a fluid system having a central chamber and two side chambers positioned on medial and lateral sides of the central chamber. Each of the side chambers are in fluid communication with the central chamber through at least one conduit that includes a valve. During walking or running, fluid within the fluid system may flow between the central chamber and the side chambers.
Fluid systems may also utilize ambient air (i.e., air drawn in from an exterior of the footwear or an exterior of the fluid system) as the system fluid. As an example, U.S. Pat. No. 6,889,451 to Passke, et al. discloses an article of footwear having a fluid system that utilizes ambient air to pressurize a pressure chamber. The fluid is drawn in through a filter, pressurized within a pump chamber in a forefoot area of the footwear, and transferred to a pressure chamber in a heel area of the footwear. When sufficiently pressurized, the pressure chamber serves to attenuate ground reaction forces. Another example of a fluid system utilizing ambient air is disclosed in U.S. Pat. No. 7,051,456 to Swigart, et al.
Various configurations of the invention involve an article of footwear with an upper and a sole structure secured to the upper. The sole structure includes a fluid system with a pump chamber and a pressure chamber located adjacent to and below the pump chamber. In some configurations, at least a portion of a fluid within the pump chamber is separated from a fluid within the pressure chamber by a single layer of a polymer material. In other configurations, the fluid system includes a fluid path extending between the pump chamber and the pressure chamber, and substantially all of the fluid path is located between the pump chamber and the pressure chamber. In yet other configurations, at least one-half of a volume of the pump chamber is located above a highest point of an upper surface of the pressure chamber. The footwear may also incorporate a plurality of separate fluid systems, each of the fluid systems having a pump chamber and a pressure chamber located adjacent to and below the pump chamber. Similar fluid systems may also be utilized in products other than footwear.
The advantages and features of novelty characterizing aspects of the invention are pointed out with particularity in the appended claims. To gain an improved understanding of the advantages and features of novelty, however, reference may be made to the following descriptive matter and accompanying drawings that describe and illustrate various embodiments and concepts related to the invention.
The foregoing Summary of the Invention and the following Detailed Description of the Invention will be better understood when read in conjunction with the accompanying drawings.
The following discussion and accompanying figures disclose various fluid system configurations. Concepts related to the fluid systems are disclosed with reference to an article of athletic footwear having a configuration suitable for the sport of running. The fluid systems are not solely limited to footwear designed for running, however, and may be incorporated into a wide range of athletic footwear styles, including basketball shoes, cross-training shoes, walking shoes, tennis shoes, soccer shoes, and hiking boots, for example. In addition, the fluid systems may be incorporated into footwear that is generally considered to be non-athletic, including dress shoes, loafers, sandals, and work boots. An individual skilled in the relevant art will appreciate, therefore, that the concepts disclosed herein relating to the fluid systems apply to a wide variety of footwear styles, in addition to the specific style discussed in the following material and depicted in the accompanying figures. In addition to footwear, concepts related to the fluid systems may be incorporated into a variety of other products, including various inflatable devices. Accordingly, aspects of the present invention have application in various technical areas, in addition to footwear.
First Fluid System
An article of footwear 10 is depicted in
Upper 20 is depicted as having a substantially conventional configuration incorporating a plurality material elements (e.g., textiles, foam, leather, and synthetic leather) that are stitched or adhesively bonded together to form an interior void for securely and comfortably receiving a foot. The material elements may be selected and located with respect to upper 20 in order to selectively impart properties of durability, air-permeability, wear-resistance, flexibility, and comfort, for example. An ankle opening 21 in heel region 13 provides access to the interior void. In addition, upper 20 may include a lace 22 that is utilized in a conventional manner to modify the dimensions of the interior void, thereby securing the foot within the interior void and facilitating entry and removal of the foot from the interior void. Lace 22 may extend through apertures in upper 20, and a tongue portion of upper 20 may extend between the interior void and lace 22. Given that various aspects of the present discussion primarily relate to sole structure 30 and at least one fluid system within sole structure 30, upper 20 may exhibit the general configuration discussed above or the general configuration of practically any other conventional or non-conventional upper. Accordingly, the structure of upper 20 may vary significantly within the scope of the present invention.
Sole structure 30 is positioned below upper 20 and includes two primary elements, a midsole 31 and an outsole 32. Midsole 31 is secured to a lower surface of upper 20 (e.g., through stitching or adhesive bonding) and operates to attenuate ground reaction forces as sole structure 30 contacts and is compressed against the ground during walking, running, or other ambulatory activities. Midsole 31 is primarily formed of a polymer foam material, such as polyurethane or ethylvinylacetate, that at least partially encapsulates a fluid system 40, which is discussed in greater detail below. Outsole 32 is secured to a lower surface of midsole 31 and is formed of a durable and wear-resistant rubber material that engages the ground. In addition, sole structure 30 may include an insole 33, which is located within the void in upper 20 and adjacent to the foot to enhance the comfort of footwear 10.
Fluid system 40 is depicted individually in
Inlet 41 permits ambient air to enter pump chamber 42 and is illustrated as an opening in an upper surface of pump chamber 42. As depicted in
Pump chamber 42 is located adjacent to pressure chamber 45 and above pressure chamber 45. Referring to
Conduit 43 provides a fluid path between chambers 42 and 45. That is, fluid passing from pump chamber 42 to pressure chamber 45 generally passes through conduit 43. As depicted in
Pressure chamber 45 is located adjacent to pump chamber 42 and below pump chamber 42. Referring to
Although pump chamber 42 is positioned within the depression in the upper surface of pressure chamber 45, at least one-half of a volume of pump chamber 42 is located above a highest point of the upper surface of pressure chamber 45. In this configuration, downward forces from the foot may continue to compress pump chamber 42 as the fluid pressure within pressure chamber 45 increases. That is, locating a significant portion of pump chamber 42 above the highest point of pressure chamber 45 ensures that pump chamber 42 may be compressed by the foot as the pressure within pressure chamber 45 increases. In other configurations, pump chamber 42 may be recessed further into pressure chamber 45 to impart a self-limiting aspect to fluid system 40. That is, as the degree to which pump chamber 42 is recessed into pressure chamber 45 increases, the resulting pressure within pressure chamber 45 may be limited. Accordingly, the relative positions of chambers 42 and 45 may be modified to alter the pressure characteristics of fluid system 40.
As discussed in greater detail below, layers 46a-46d are polymer materials (e.g., thermoplastic polymer materials) that are bonded or otherwise joined about their peripheries to form chambers 42 and 45. In order to impart shape to chambers 42 and 45, layers 46a-46d may be heated or otherwise thermoformed during the manufacturing processes of chambers 42 and 45. Prior to shaping chambers 42 and 45, inlet 41 may be formed as an aperture extending through layer 46a, conduit 43 may be formed as an aperture extending through both of layers 46b and 46c, and valve 44 may be positioned between layers 46b and 46c. As an alternative to being formed from layers 46a-46d, chambers 42 and 45 may be formed through blow-molding or rotational-molding processes, for example.
When formed from layers 46a-46d, chambers 42 and 45 may be formed separately and subsequently located adjacent to each other within sole structure 30. That is, pump chamber 42 may be formed from layers 46a and 46b, and pressure chamber 45 may be formed separately from layers 46c and 46d. In this configuration, two layers of polymer material (i.e., layers 46b and 46c) separate the fluid within pump chamber 42 from the fluid within pump chamber 45. As an alternative to this configuration, layer 46b may be eliminated such that chambers 42 and 45 are formed as a single structure. Referring to the cross-section of
As discussed above, locating a significant portion of pump chamber 42 above the highest point of pressure chamber 45 ensures that pump chamber 42 may be compressed by the foot as the pressure within pressure chamber 45 increases. Although a configuration wherein at least one-half of the volume of pump chamber 42 is located above the highest point of pressure chamber 45 generally ensures that pump chamber 42 may be compressed, some configurations of fluid system 40 may benefit when a greater volume of pump chamber 42 is exposed. Referring to
When conduit 43 is formed as apertures that extend through layers 46b and 46c, portions of valve 44 may extend or otherwise protrude into pressure chamber 45, as depicted in
Fluid system 40 is depicted in
An advantage to fluid system 40 relates to the relative locations of pump chamber 42 and pressure chamber 45. As discussed above, pump chamber 42 is located above pressure chamber 45. That is, chambers 42 and 45 are vertically-aligned within sole structure 30. Initially (i.e., when the individual first places footwear 10 upon a foot), the fluid pressure within each of chambers 42 and 45 may be substantially equal to the fluid pressure on the exterior of footwear 10. During the operation of fluid system 40 (i.e., as the individual takes successive steps during walking and running), two events occur simultaneously. First, the downward force from the foot compresses pump chamber 42 and induces fluid within pump chamber 42 to enter and pressurize pressure chamber 45. Second, the pressurized fluid within pressure chamber 45 attenuates the equal and opposite force (i.e., the ground reaction force) upon the foot. In effect, therefore, the same force that serves to operate fluid system 40 is also attenuated by fluid system 40. If, for example, pump chamber 42 was separate from pressure chamber 45, then a force from one portion of the foot would operate fluid system 40 and a force from another portion of the foot would be attenuated by fluid system 40. Accordingly, by vertically-aligning chambers 42 and 45, forces that operate fluid system 40 are also attenuated by fluid system 40. Eventually, fluid system 40 reaches an equilibrium state wherein the downward force from the foot compresses pump chamber 42, but does not induce fluid within pump chamber 42 to enter pressure chamber 45.
Referring to
The configuration of
A variety of materials are suitable for layers 46a-46d of chambers 42 and 45, including barrier materials that are substantially impermeable to the fluid within fluid system 40. Such barrier materials may include, for example, alternating layers of thermoplastic polyurethane and ethylene-vinyl alcohol copolymer, as disclosed in U.S. Pat. Nos. 5,713,141 and 5,952,065 to Mitchell et al. A variation upon this material wherein the center layer is formed of ethylene-vinyl alcohol copolymer, the two layers adjacent to the center layer are formed of thermoplastic polyurethane, and the outer layers are formed of a regrind material of thermoplastic polyurethane and ethylene-vinyl alcohol copolymer may also be utilized. Another suitable material is a flexible microlayer material that includes alternating layers of a gas barrier material and an elastomeric material, as disclosed in U.S. Pat. Nos. 6,082,025 and 6,127,026 to Bonk et al. Although chambers 42 and 45 may be formed of the barrier materials discussed above, more economical thermoplastic elastomer materials that are at least partially impermeable to the fluid within fluid system 40 may also be utilized. As discussed above, fluid system 40 operates to draw air into chambers 42 and 45 in order to provide ground reaction force attenuation to footwear 10. If a portion of the fluid within pump chamber 42 or pressure chamber 45 should escape from fluid system 40 by diffusion, for example, then fluid system 40 will operate to draw additional fluid into chambers 42 and 45, thereby replenishing the escaped fluid. Accordingly, the material forming chambers 42 and 45 need not provide a barrier that is substantially impermeable to the fluid within fluid system 40, but may be at least partially impermeable to the fluid within fluid system 40. Suitable polymer materials include, therefore, thermoplastic elastomers such as polyurethane, polyester, polyester polyurethane, and polyether polyurethane. In addition to decreased manufacturing costs, a benefit of utilizing these thermoplastic elastomers is that the specific material forming chambers 42 and 45 may be selected based primarily upon the engineering properties of the material, rather than the barrier properties of the material. Accordingly, the material forming chambers 42 and 45 may be selected to exhibit a specific tensile strength, flexibility, durability, degree of light transmission, color, elasticity, resistance to corrosion or chemical breakdown, or abrasion resistance, for example.
Second Fluid System
As an alternative to fluid system 40, footwear 10 may also incorporate a fluid system 140, which is depicted individually in
Based upon the above discussion, fluid system 140 is structurally-similar to fluid system 40 and many of the considerations discussed above for fluid system 40 apply equally to fluid system 140. As with fluid system 40, therefore, pump chamber 142 is located adjacent to pressure chamber 145 and above pressure chamber 145 to impart the advantages discussed above. Although pump chamber 142 is positioned within a depression in an upper surface of pressure chamber 145, at least one-half of a volume of pump chamber 142 is located above a highest point of the upper surface of pressure chamber 145. In other configurations, however, a greater or lesser volume of pump chamber 142 may be located above pressure chamber 145. Although two layers of polymer material are depicted as separating the fluid within pump chamber 142 from the fluid within pump chamber 145, a single layer of polymer material may separate the fluid within pump chamber 142 from the fluid within pump chamber 145 in some configurations of fluid system 140.
When incorporated into sole structure 30, a single fluid system 140 may be utilized such that chambers 142 and 145 are located within heel region 13 and collecting chamber 146 is located in midfoot region 12, as depicted in
Third Fluid System
With reference to
In operation, a fluid (i.e., air from the exterior of fluid system 240) is drawn through inlets and into each of first pump chamber 242 and second pump chamber 242′. As first pump chamber 242 is compressed by a downward force from the foot, the fluid enters first conduit 243 and passes through a valve to enter second pressure chamber 245′. Similarly, as second pump chamber 242′ is compressed by a downward force from the foot, the fluid enters second conduit 243′ and passes through a valve to enter first pressure chamber 245. In effect, therefore, two of fluid system 40 are cross-linked such that compression of one pump chamber pressurizes a separate pressure chamber.
The invention is disclosed above and in the accompanying drawings with reference to a variety of embodiments. The purpose served by the disclosure, however, is to provide an example of the various features and concepts related to the invention, not to limit the scope of the invention. One skilled in the relevant art will recognize that numerous variations and modifications may be made to the embodiments described above without departing from the scope of the present invention, as defined by the appended claims.
