Articles of footwear generally include two primary elements, an upper and a sole structure. The upper is formed from a variety of material elements (e.g., textiles, foam, leather, and synthetic leather) that are stitched or adhesively bonded together to form a void on the interior of the footwear for comfortably and securely receiving a foot. An ankle opening through the material elements provides access to the void, thereby facilitating entry and removal of the foot from the void. In addition, a lace is utilized to modify the dimensions of the void and secure the foot within the void.
The sole structure is located adjacent to a lower portion of the upper and is generally positioned between the foot and the ground. In many articles of footwear, including athletic footwear, the sole structure conventionally incorporates an insole, a midsole, and an outsole. The insole is a thin compressible member located within the void and adjacent to a lower surface of the void to enhance footwear comfort. The midsole, which may be secured to a lower surface of the upper and extends downward from the upper, forms a middle layer of the sole structure. In addition to attenuating ground reaction forces (i.e., providing cushioning for the foot), the midsole may limit foot motions or impart stability, for example. The outsole, which may be secured to a lower surface of the midsole, forms the ground-contacting portion of the footwear and is usually fashioned from a durable and wear-resistant material that includes texturing to improve traction.
The conventional midsole is primarily formed from a foamed polymer material, such as polyurethane or ethylvinylacetate, that extends throughout the length and width of the footwear. In some articles of footwear, the midsole may include a variety of additional footwear elements that enhance the comfort or performance of the footwear, including plates, moderators, fluid-filled chambers, lasting elements, or motion control members. In some configurations, any of these additional footwear elements may be located between the midsole and either of the upper and outsole, embedded within the midsole, or encapsulated by the foamed polymer material of the midsole, for example. Although many conventional midsoles are primarily formed from a foamed polymer material, fluid-filled chambers or other non-foam structures may form a majority of some midsole configurations.
In an example of an article of footwear, a sole structure of the footwear includes a first midsole element and a second midsole element. Whereas the first midsole element may be formed from a foamed polymer material, the second midsole element may be formed from a non-foamed polymer material. The second midsole element is positioned adjacent to the first midsole element, and the second midsole element defines a plurality of apertures, with ends of at least a portion of the apertures being located adjacent to a surface of the first midsole element. In some configurations, the second midsole element may also define a protrusion that extends into the first midsole element, or a portion of the second midsole element that forms a side surface of the sole structure may include an elongate indentation.
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 and the following Detailed Description will be better understood when read in conjunction with the accompanying drawings.
The following discussion and accompanying figures disclose an article of footwear incorporating a sole structure with elements having materials with different compressibilities. Concepts related to the sole structure are disclosed with reference to a footwear configuration that is suitable for running. The sole structure is not limited to footwear designed for running, however, and may be utilized with a wide range of athletic footwear styles, including baseball shoes, basketball shoes, tennis shoes, football shoes, cross-training shoes, walking shoes, and soccer shoes, for example. The sole structure may also be utilized with footwear styles that are generally considered to be non-athletic, including dress shoes, loafers, sandals, and boots, for example. The concepts disclosed herein apply, therefore, to a wide variety of footwear styles, in addition to the specific style discussed in the following material and depicted in the accompanying figures.
General Footwear Configuration
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 footwear 10 discussed in the following material primarily relate to 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.
Sole Structure Configuration
Sole structure 30 is secured to a lower area of upper 20 and extends downward from upper 20. When a foot is located within the void in upper 20, sole structure 30 is positioned to extend between the foot and the ground. In this position, sole structure 30 may, for example, limit foot motions, impart stability, or attenuate ground reaction forces (i.e., provide cushioning) when sole structure 30 is compressed by the foot. With reference to
Second midsole element 32 is depicted individually in
The contoured configuration of upper surface 41 includes a substantially planar peripheral area 44 and a protrusion 45 that extends upward from a central area of upper surface 41. As depicted in
Second midsole element 32 defines a plurality of apertures 46 that extend in a substantially vertical direction and through second midsole element 32. That is, apertures 46 extend between upper surface 41 and lower surface 42, and upper ends of apertures 46 are located adjacent to the lower surface of first midsole element 31. Although portions of first midsole element 31 may extend into apertures 46 when sole structure 30 is compressed, as discussed in greater detail below, material may be absent from apertures 46. More particularly, a fluid (e.g., air) rather than a solid material may be located within apertures 46. As depicted in
Sidewall portion 43 extends upward from upper surface 41 and is exposed to form a portion of the sidewall of sole structure 30 in heel region 13. More particularly, opposite sections of sidewall portion 43 are located on lateral side 14 and medial side 15, and a central section of sidewall portion 43 extends around a rear area of sole structure 30. The sections of sidewall portion 43 located on lateral side 14 and medial side 15 each define an elongate indentation 47 that extends into second midsole element 32 from the exterior of sole structure 30. That is, indentations 47 extend into sidewall portion 43 and exhibit elongate shapes that extend along portions of lateral side 14 and medial side 15 in a generally horizontal direction.
One factor that determines the degree to which sole structure 30 limits foot motions, imparts stability, or attenuates ground reaction forces relates to the properties of the materials forming first midsole element 31 and second midsole element 32. Either of elements 31 and 32 may be formed from foamed polymer materials or non-foamed polymer materials. Examples of suitable foamed polymer materials include polyurethane and ethylvinylacetate foams that are conventionally utilized in footwear sole applications. Examples of suitable non-foamed polymer materials include a variety of thermoplastic and thermoset polymers, such as silicone, polyurethane, polyolefin, polyamide, polyurea, polyester, and styrene-olefin-rubber block copolymer. In some configurations, the non-foamed polymer material may be a gel material. Similarly, in some configurations, second midsole element 32 may be formed from a gel material. Another example of a suitable non-foamed polymer material for either of elements 31 and 32 is a cast polyurethane. In further configurations, first midsole element 31 may be formed to have the configuration of a compressible fluid-filled chamber.
In comparing the properties of the materials discussed above, the foamed polymer materials generally exhibit greater compressibility than the non-foamed polymer materials. When the foot presses downward upon sole structure 30, therefore, portions of sole structure 30 that are formed from a foamed polymer material will generally compress more than portions of sole structure 30 that are formed from a non-foamed polymer material. By selecting materials with different degrees of compressibility for elements 31 and 32, the manner in which sole structure 30 limits foot motions, imparts stability, or attenuates ground reaction forces (i.e., provide cushioning) may be affected. As an example of a combination of materials that may be utilized, first midsole element 31 may be formed from a foamed polymer material and second midsole element 32 may be formed from a non-foamed polymer material. In this configuration, when sole structure 30 is compressed between the foot and the ground, each of elements 31 and 32 may compress, but the foamed polymer material of first midsole element 31 will generally compress more than non-foamed polymer material of second midsole element 32. By incorporating structures such as protrusion 45, apertures 46, and indentation 47 into second midsole element 32, the compression characteristics of second midsole element 32 may be engineered to impart specific degrees of compressibility in different areas of sole structure 30. That is, structures such as protrusion 45, apertures 46, and indentation 47 in second midsole element 32 may be used to provide specific compression characteristics to sole structure 30.
The Running Cycle
Although the foamed polymer material of first midsole element 31 may compress more than the non-foamed polymer material of second midsole element 32, the structure of second midsole element 32 imparts specific compression characteristics to sole structure 30. The typical motion of the foot during running cycle proceeds as follows: First, the heel strikes the ground, followed by the ball of the foot. As the heel leaves the ground, the foot rolls forward so that the toes make contact, and finally the entire foot leaves the ground to begin another cycle. During the time that the foot is in contact with the ground and rolling forward, the foot also rolls from the outside or lateral side to the inside or medial side, a process called pronation. By incorporating features such as protrusion 45, apertures 46, and indentation 47 into second midsole element 32, ground reaction forces may be attenuated during the running cycle. In addition, second midsole element 32 may enhance the degree to which sole structure 30 imparts stability and limits the rolling motion of the foot to moderate pronation during the running cycle.
The manner in which sole structure 30 compresses and the manner in which features of second midsole element 32 affect the compression of sole structure 30 during the running cycle will now be discussed. Referring to
As the running cycle continues, foot 51 rolls forward and more toward medial side 15, as depicted in
When the foamed polymer material of first midsole element 31 is subjected to a compressive force, cells or gas-filled pockets within the foamed polymer material decrease in volume to permit the foamed polymer material to compress. That is, the cells within the foamed polymer material decrease in size as first midsole element is compressed by foot 51. In contrast, the non-foamed polymer material of second midsole element 32 does not include a substantial amount of cells or gas-filled pockets. In order to compress, therefore, the non-foamed polymer material expands from the compressed area. Apertures 46 permit the non-foamed polymer material to expand. That is the non-foamed polymer material expands into apertures 46 as second midsole element 32 is compressed. Referring to
In addition to providing spaces for the expansion of the non-foamed polymer material, apertures 46 also provide a space for the foamed polymer material of first midsole element 31 to expand. Referring to
As the running cycle continues, foot 51 continues to roll forward and toward medial side 15 such that substantially all of a width of outsole 33 is in contact with ground surface 52, as depicted in
Apertures 46 decrease in width to permit protrusion 45 to compress or otherwise decrease in thickness. The configuration of protrusion 45 also facilitates compression in second midsole element 32. Protrusion 45 extends upward above the surface of peripheral area 44 and is surrounded by the foamed polymer material of first midsole element 31. When a compressive force is applied to protrusion 45, the non-foamed polymer material forming protrusion 45 may expand outward to effectively increase the width of protrusion 45. That is, the non-foamed polymer material forming protrusion 45 may expand outward and into the foamed polymer material of first midsole element 31. Accordingly, various factors contributing to the compressibility of protrusion 45 include the shape of protrusion 45, the location of protrusion 45 within the foamed polymer material of first midsole element 31, and the presence of apertures 46 through protrusion 45.
As discussed above, protrusion 45 is located to generally correspond with a position of the calcaneus bone of foot 51. That is, the calcaneus bone is generally positioned above protrusion 45. During the portion of the running cycle depicted in
As the running cycle continues further, sole structure 30 separates from the ground, as depicted in
Additional Sole Structure Configurations
Based upon the above discussion, the various structural features of second midsole element 32 (i.e., protrusion 45, apertures 46, and indentation 47) contribute to the compressibility of sole structure 30. More particularly, the various structural features affect the compressibility of sole structure 30 throughout the running cycle. Whereas foamed polymer materials generally exhibit substantially uniform compression properties, second midsole element 32 is specifically structured to impart different degrees of compressibility in different locations. Accordingly, the degree of ground reaction force attenuation imparted by different areas of sole structure 30 may be modified by changing the properties (e.g., shape, location, thickness(of protrusion 45, apertures 46, and indentation 47, for example.
The above discussion of sole structure 30 provides an example of one suitable configuration for first midsole element 31 and second midsole element 32. Various features of sole structure 30 may be varied, however, to impart different degrees of motion control, stability, or ground reaction force attenuation for the foot. Depending upon the specific activity for which footwear 10 is intended to be used, the configuration of first midsole element 31 and second midsole element 32 may vary significantly. More particularly, the configuration of first midsole element 31 and second midsole element 32 may vary to provide enhanced performance for sports that include basketball, tennis, football, walking, and soccer, for example. The configuration of first midsole element 31 and second midsole element 32 may also vary to provide different degrees of motion control, stability, or ground reaction force attenuation when footwear 10 is intended for non-athletic activities. Accordingly, the specific configuration of sole structure 30 discussed above and depicted in the figures is intended to provide one example of the manner in which footwear 10 may be structured.
In the above discussion and figures of footwear 10, sole structure 30 includes first midsole element 31, second midsole element 32, and outsole 33. In further configurations of footwear 10, however, sole structure 30 may include a variety of additional footwear elements that enhance the comfort or performance of footwear 10, including plates, moderators, fluid-filled chambers, lasting elements, or motion control members, for example. Although first midsole element 31 is depicted as being secured directly to the lower area of upper 20, any of these additional footwear elements may be located between first midsole element 31 and upper 20. Additionally, any of these additional footwear elements may be (a) located between first midsole element 31 and outsole 33, (b) located between first midsole element 31 and second midsole element 32, (c) located between second midsole element 32 and outsole 33, (d) embedded within either of first midsole element 31 and second midsole element 32, or (e) encapsulated by the materials forming first midsole element 31 and second midsole element 32, for example. Sole structure 30 may also incorporate an insole or sockliner that is located within the void in upper 20 and adjacent a lower surface of the foot to enhance comfort.
The configuration of second midsole element 32 may also be varied. Referring to
The combination of first midsole element 31 and second midsole element 32 extend between upper 20 and outsole 33. The manner in which first midsole element 31 and second midsole element 32 interface in this area may, however, vary significantly. Referring to
The configuration of second midsole element 32 depicted in
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.
This non-provisional U.S. Patent Application claims priority to and is a Continuation of prior U.S. patent application Ser. No. 12/174,257, which was filed in the U.S. Patent and Trademark Office on Jul. 16, 2008 and entitled Article Of Footwear Incorporating A Sole Structure With Elements Having Different Compressibilities, such prior U.S. Patent Application being entirely incorporated herein by reference. U.S. patent application Ser. No. 12/174,257 claims priority under 35 U.S.C. §119(e)(1) to provisional U.S. patent application Ser. No. 60/969,078, which was filed in the U.S. Patent and Trademark Office on Aug. 30, 2007 and entitled Article Of Footwear Incorporating A Sole Structure With Elements Having Different Compressibilities, such provisional U.S. Patent Application being entirely incorporated herein by reference.
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Child | 14920630 | US |