COMPRESSIBLE STRUCTURE SECURED TO AN UPPER OF AN ARTICLE OF FOOTWEAR

Abstract

An article of footwear has an upper and a compressible structure secured to the upper. The compressible structure can include one or more materials with physical properties that singly or in vertical aggregate, generally conform to those of a spring, following Hooke's Law, F=kx, whereby the ratio of k/k.sub.ideal approaches a value of 1.0, wherein the ideal k value is defined as k.sub.ideal=F.sub.impulsex.sub.s-max, for a compressible structure region located adjacent to the corresponding region of the foot that generates the force impulse.

Claims

1.-18. (canceled)

19. A running shoe tuned to a running speed of a runner wearing the shoe, the shoe consisting of (a) an upper that secures the foot to the shoe, and (b) a compressible sole structure under the upper that compresses in proportion to the amount of pressure applied during the gait cycle of the runner to no more than the limit of elasticity and decompresses when pressure is decreased and removed from the compressible sole structure during the ground contact phase of the gait cycle of the runner, the shoe characterized in that: i) the gait cycle of the runner to which the shoe is tuned consists of: first, a time when the shoe initially contacts the ground; second, a time during which gravity and the runner's leg muscles apply increasing force to the shoe; third, a time of maximum application of force to the shoe, fourth, a time of application of decreasing force to the shoe until the force applied to the shoe is zero but the shoe remains in contact with the ground; fifth, a time when the shoe is removed from contact with the ground; sixth, a time when the shoe is moved forward before again contacting the ground, ii) the compressible sole layer compresses to no more than its limit of elasticity upon application of increasing force to the shoe during the initial stage of the stride, iii) the compressible sole layer decompresses in response to decreasing force during the time after the maximum application of force to the shoe and until the shoe leaves the ground.

20. The running shoe of claim 19, wherein the compressible sole layer decompresses substantially completely during the time after the maximum application of force to the shoe during the contact period of the runner and before the shoe leaves the ground during the gait cycle of the runner.

21. The running shoe of claim 19, wherein the compressible sole layer decompresses at least 90% during the time from after the maximum application of force to the shoe during the contact period of the runner and before the shoe leaves the ground during the gait cycle of the runner.

22. The running shoe of claim 19, wherein the compressible sole layer decompresses at least 50% during the time from after the maximum application of force to the shoe during the contact period of the runner and before the shoe leaves the ground during the gait cycle of the runner.

23. The running shoe of claim 19, wherein the compressible sole layer consists of a plurality of regions, each region of the compressible sole layer below a corresponding region of the foot and tuned to the forces applied to that region of the compressible sole layer by the corresponding region of the foot.

24. The running shoe of claim 23, wherein each of the plurality of regions of the compressible sole layer decompresses substantially completely during the time after the maximum application of force to that region of the compressible sole layer during the contact period of the runner and before the corresponding portion of the outer sole leaves the ground during the gait cycle of the runner.

25. The running shoe of claim 23, wherein each of the plurality of regions of the compressible sole layer decompresses at least 90% during the time from the maximum application of force to that region of the compressible sole to the time when the shoe leaves the ground.

26. The running shoe of claim 23, wherein each of the plurality of regions of the compressible sole layer decompresses at least 50% during the time from the maximum application of force to that region of the compressible sole to the time when the shoe leaves the ground.

27. The running shoe of claim 23, wherein the regions of the foot consist of (a) the heel of the runner's foot, (b) the ball of the runner's foot, (c) the arch of the runner's foot, (d) the toes of the runner's foot.

28. The running shoe of claim 23, wherein the regions of the foot consist of any subregion of the plantar surface of the runner's foot that may exert a differential force onto an adjacent subregion of the compressible layer.

29. An article of footwear having an upper and a compressible structure secured to the upper, the compressible structure providing cushioning and energy return to the wearer by means of first compression of the compressible structure followed by expansion of the compressible structure.

30. The article of footwear as in claim 29, wherein the cushioning and energy return are maximized for a running speed zone by tuning the ratio of k/k.sub.ideal to approach a value of 1.0.

31. The article of footwear as in claim 29, wherein the compressible structures are tuned to a progression of runner speeds and allow for distinct versions of the footwear differentiated by runner speed zone.

32. The article of footwear as in claim 31, wherein the runner is matched to a particular footwear version according to the runner's intended running speed.

33. The article of footwear as in claim 31, wherein the runner's intended running speed has a midpoint speed and a range of +/0.3 m/s.

34. The article of footwear as in claim 31, wherein the runner's intended running speed has a midpoint speed and a range of +/1 m/s.

35. The article of footwear as in claim 31, wherein the runner's intended running speed has a midpoint speed and a range of +/2 m/s.

36. The running shoe of claim 19, further comprising a midsole element formed from polyurethane or ethylvinylacetate.

37. The article of footwear as in claim 31, further comprising a midsole element including at least one of (a) a plate formed from a semi-rigid polymer material, (b) a combination of a plate and foam material, or (c) a plurality of foam-based and semi-rigid structures.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The presently disclosed technology will be better understood in light of the accompanying figures.

[0048] FIG. 1 depicts an array of pressure measuring nodes arranged in an orthogonal matrix with spacing of 5.8 mm.

[0049] FIG. 2 is a schematic for a typical force plate used in biomechanical studies.

[0050] FIG. 3 is a plot of peak vertical ground reaction force from the plantar foot surface of a human runner with the anatomical regions (heel, arch, ball, toes) demarcated with boxes.

[0051] FIG. 4 is a graph depicting the vertical ground reaction force vs time profiles of four anatomical regions (heel, arch, ball, toes) of the foot for a single step of a runner overlaid on the profile for the sum of all forces vs time.

[0052] FIG. 5 is an annotated graph depicting vertical ground reaction forces vs time profiles from a human runner with callouts marking the impact forces and the propulsion forces.

[0053] FIG. 6 is a graph of vertical ground reaction force vs time profiles from the ball-of-foot region of a runner for a series of steps with progressively increasing runner speed.

[0054] FIG. 7 is an annotated graph depicting vertical ground reaction forces vs time profiles from four regions of the foot experiencing a forefoot-strike pattern.

[0055] FIGS. 8a and 8b are graphs of PE/PE.sub.max vs runner speed and midsole spring constant respectively.

[0056] FIG. 9 is lateral side elevational view of an article of footwear.

[0057] FIG. 10 is a medial side elevational view of the article of footwear.

[0058] FIG. 11 is an exploded perspective view of a sole structure of the article of footwear.

[0059] FIGS. 12a and 12b are cross-sectional views of the sole structure, as defined by lateral and longitudinal section lines 4A and 4B in FIG. 11.

[0060] FIGS. 13a and 13b are cross-sectional views of the sole structure, as defined by section lines 4A and 4B in FIG. 11.

DETAILED DESCRIPTION

[0061] The following discussion and accompanying figures disclose various sole structure configurations for articles of footwear. Concepts related to the sole structure configurations are disclosed with reference to footwear that is suitable for running. The sole structure configurations are not limited to footwear designed for running, however, and may be utilized with a wide range of athletic footwear styles, including basketball shoes, cross-training shoes, cycling shoes, football shoes, soccer shoes, tennis shoes, and walking shoes, for example. The sole structure configurations may also be utilized with footwear styles that are generally considered to be non-athletic, including dress shoes, loafers, sandals, and boots. The concepts disclosed herein may, therefore, 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.

General Footwear Structure

[0062] An article of footwear 10 is depicted in FIGS. 9 and 10 as including an upper 20 and a sole structure 30. For reference purposes, footwear 10 may be divided into four general regions: a toes region 11, a ball-of-foot region 12, a midfoot region 13, and a heel region 14, as shown in FIGS. 9 and 10. Footwear 10 also includes a lateral side 15 and a medial side 16. Toes region 11 generally includes portions of footwear 10 corresponding with the phalanges. Ball-of-foot region 12 generally includes portions of footwear 10 corresponding with the joints between the metatarsals and the phalanges and the metatarsal bones, midfoot region 13 generally includes portions of the arch (both medial and lateral arches) in an area below the tarsal bones, and heel region 14 corresponds with the rear portion of the foot, including the calcaneus bone. Lateral side 15 and medial side 16 extend through each of regions 11-14 and correspond with opposite sides of footwear 10. Regions 11-14 and sides 15-16 are not intended to demarcate precise areas of footwear 10. Rather, regions 11-14 and sides 15-16 are intended to represent general areas of footwear 10 to aid in the following discussion. In addition to footwear 10, regions 11-14 and sides 15-16 may also be applied to upper 20, sole structure 30, and individual elements thereof.

[0063] 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 14 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, upper 20 may exhibit the general configuration discussed above or the general configuration of practically any other conventional or non-conventional upper. Other devices, such as Velcro tabs, can be substituted for laces. Accordingly, the structure of upper 20 may vary significantly within the scope of the presently disclosed technology.

[0064] Sole structure 30 is secured to upper 20 and has a configuration that extends between upper 20 and the ground. In general, the various elements of sole structure 30 exhibit rebound properties (impart cushioning and energy return), affect the overall motion of the foot, and impart traction during walking, running, or other ambulatory activities. Additional details concerning the configuration of sole structure 30 will be described below.

General Sole Structure Configuration

[0065] Sole structure 30 is depicted in FIG. 11 and includes a midsole element 40 and an outsole 50. In addition to these elements, sole structure 30 may incorporate one or more plates, moderators, or spring-like structures, for example, which further enhance the ground reaction force cushioning and potential energy storage characteristics of sole structure 30 or the performance properties of footwear 10. Additionally, sole structure 30 may incorporate a sockliner (not depicted) that is located within a lower portion of the void in upper 20 to enhance the comfort of footwear 10.

[0066] Midsole element 40 extends throughout a length of footwear 10 (i.e., through each of regions 11-14) and a width of footwear 10 (i.e., between sides 15 and 16). The primary surfaces of midsole element 40 are an upper surface 41, an opposite lower surface 42, and a side surface 43 that extends between surfaces 41 and 42. Upper surface 41 is joined to a lower area of upper 20, thereby joining sole structure 30 to upper 20. Lower surface 42 is joined with outsole 50 in regions 11-14. Surface 42 may also serve as outsole 50 in portions of regions 11-14, none of surface 42 or the entirety of surface 42. Additionally, side surface 43 forms an exposed sidewall of sole structure 30 on both lateral side 15 and medial side 16.

[0067] A variety of materials may be utilized to form midsole element 40. As an example, midsole element 40 may be formed from a polymer foam material, such as polyurethane or ethylvinylacetate and exhibit the functional properties of rebound according to desired design specifications. In some configurations, midsole element 40 may also be (a) a plate formed from a semi-rigid polymer material or (b) a combination of a plate and foam material, (c) a plurality of foam-based and semi-rigid structures. In addition to the foam material, midsole element 40 may incorporate one or more foam elements defined spatially and with modulus Y, semi-rigid structures with spatial dimensions S and L and net modulus Y, for example, that create the rebound characteristics of sole structure 30 or the overall performance properties of footwear 10. In some configurations, midsole element 40 may also encapsulate foam-based, semi-rigid, and combination structures within a foam chassis 41. In other configurations, midsole element 40 may encapsulate foam-based, semi-rigid, and combination structures within a portion of regions 11-14. Midsole element 40 may also comprise no encapsulating materials, allowing the foam-based, semi-rigid, and combination structures to be exposed along the sidewall 43 and bonded directly to upper 20 and to outsole 50, where an outsole 50 is present.

[0068] The midsole can be divided into several regions along the length of the shoe as shown in FIGS. 9 & 12. Individual midsole structural elements 60 encapsulated within a foam chassis 41 may be configured as in FIGS. 12a and 12b. Midsole elements 60 may be formed of a wide range of polymer materials with engineering properties of the materials (e.g., tensile strength, stretch properties, fatigue characteristics, dynamic modulus, and loss tangent) as well as the ability of the materials to prevent the diffusion of any fluid contained within chamber walls. The sum behavior of all the materials comprising a single region (11, 12, 13, or 14) located directly under the corresponding foot anatomical feature will generate the net rebound effect in the specified region of the midsole. The particular placement, shape, and size of individual elements 60 may vary greatly between embodiments. The number of elements 60 and the arrangement of the elements within the chassis 41 as shown in FIGS. 12a and 12b, represent a single example and does not represent the possible variety of configurations available to the designers within the context of the presently disclosed technology.

[0069] Midsole element 40 may be comprised entirely of structural elements 60 with no encapsulating foam element 41, as depicted in FIGS. 13a and 13b. Midsole 40 may include voids of open space 61, and may expose any of the outer surfaces or may cover those surfaces with paint, film, cloth, or other polymer material 62 for the purposes of abrasion resistance or cosmetics. Outer surface coatings 62 may or may not contribute to the rebound characteristics of the structural elements 60 and the midsole element 40.

[0070] The presently disclosed technology is disclosed above and in the accompanying figures with reference to a variety of configurations. 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 configurations described above without departing from the scope of the present invention, as defined by the appended claims.