Patent Publication Number: US-8978272-B2

Title: Article of footwear with forefoot plates

Description:
RELATED APPLICATIONS 
     This application is a continuation-in-part of application Ser. No. 13/413,800, filed on Mar. 7, 2012, which is a continuation of U.S. Pat. No. 8,151,485, issued on Apr. 10, 2012, each of which is entirely incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to an article of footwear, and, in particular, to an article of footwear with forefoot plates. 
     BACKGROUND OF THE INVENTION 
     Conventional articles of athletic footwear include two primary elements, an upper and a sole structure. The upper provides a covering for the foot that comfortably receives and securely positions the foot with respect to the sole structure. In addition, the upper may have a configuration that protects the foot and provides ventilation, thereby cooling the foot and removing perspiration. The sole structure is secured to a lower portion of the upper and is generally positioned between the foot and the ground. In addition to attenuating ground reaction forces, the sole structure may provide traction, control foot motions (e.g., by resisting over pronation), and impart stability, for example. Accordingly, the upper and the sole structure operate cooperatively to provide a comfortable structure that is suited for a wide variety of activities, such as walking and running. 
     The sole structure generally 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 upper and adjacent to a plantar (i.e., lower) surface of the foot to enhance footwear comfort. The midsole, which is conventionally secured to the upper along the length of the upper, forms a middle layer of the sole structure and is primarily responsible for attenuating ground reaction forces. The outsole forms the ground-contacting element of footwear and is usually fashioned from a durable, wear-resistant material that includes texturing to improve traction. 
     The conventional midsole is primarily formed from a resilient, polymer foam material, such as polyurethane or ethylvinylacetate, that extends throughout the length of the footwear. The properties of the polymer foam material in the midsole are primarily dependent upon factors that include the dimensional configuration of the midsole and the specific characteristics of the material selected for the polymer foam, including the density of the polymer foam material. By varying these factors throughout the midsole, the relative stiffness and degree of ground reaction force attenuation may be altered to meet the specific demands of the activity for which the footwear is intended to be used. In addition to polymer foam materials, conventional midsoles may include, for example, one or more fluid-filled bladders and moderators. 
     It would be desirable to provide an article of footwear that reduces or overcomes some or all of the difficulties inherent in prior known devices. Particular objects and advantages will be apparent to those skilled in the art, that is, those who are knowledgeable or experienced in this field of technology, in view of the following disclosure of the invention and detailed description of certain embodiments. 
     SUMMARY 
     The principles of the invention may be used to advantage to provide an article of footwear with forefoot plates. In accordance with a first aspect, an article of footwear includes an upper and a sole assembly secured to the upper. The sole assembly has an upper plate and a lower plate in a forefoot portion of the sole assembly, and a plurality of lower plate arms curving downwardly from the upper plate. 
     In accordance with another aspect, an article of footwear includes an upper and a sole assembly secured to the upper. The sole assembly includes an upper plate and a lower plate having a plurality of lower plate arms curving downwardly from a lateral side of a forefoot portion of the upper plate and a plurality of lower plate arms curving downwardly and outwardly from a medial side of a forefoot portion of the upper plate. 
     In accordance with a further aspect, an article of footwear includes an upper and a midsole secured to a lower surface of the upper, with a lower surface of the midsole secured to an upper surface of the upper plate. A sole assembly is secured to a lower surface of the midsole and includes an upper plate and a lower plate of unitary construction with the upper plate. The lower plate has a plurality of lateral lower plate arms curving downwardly from a lateral side of a forefoot portion of the upper plate and a plurality of medial lower plate arms curving downwardly from a medial side of a forefoot portion of the upper plate. Each of a plurality of outsole portions is secured to a lower surface of a corresponding lower plate arm. 
     Substantial advantage is achieved by providing footwear with forefoot plates. In particular, certain embodiments provides a spring-like action in lower plate arms of the footwear, which are pre-flexed in a curved condition, thereby helping a user change direction and cut when using footwear, thereby improving propulsion for the user. The lower plate arms are curved to help relieve stress encountered during use of the footwear. 
     These and additional features and advantages disclosed here will be further understood from the following detailed disclosure of certain embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an elevation view of an article of footwear with a forefoot plate. 
         FIG. 2  is a bottom plan view of the article of footwear of  FIG. 1 , shown without an outsole. 
         FIG. 3  is a partial section view of the article of footwear of  FIG. 1 , taken along line  3 - 3  of  FIG. 1 . 
         FIG. 4  is a partial section view of an alternative embodiment of the article of footwear of  FIG. 1 . 
         FIG. 5  is a bottom plan view of another alternative embodiment of the article of footwear of  FIG. 1 , shown without an outsole. 
         FIG. 6  is a partial section view of an alternative embodiment of the article of footwear of  FIG. 1 . 
         FIG. 7  is a perspective view of a further alternative embodiment of the article of footwear of  FIG. 1 . 
         FIG. 8  is a perspective view of yet a further alternative embodiment of the article of footwear of  FIG. 1 . 
         FIG. 9  is a section view of an embodiment of the plate assembly of the article of footwear of  FIG. 7 . 
         FIG. 10  is a plan view of an alternative embodiment of the plate of the article of footwear of  FIG. 7 . 
     
    
    
     The figures referred to above are not drawn necessarily to scale and should be understood to provide a representation of the invention, illustrative of the principles involved. Some features of the article of footwear with a forefoot plate depicted in the drawings have been enlarged or distorted relative to others to facilitate explanation and understanding. The same reference numbers are used in the drawings for similar or identical components and features shown in various alternative embodiments. Articles of footwear with a forefoot plate as disclosed herein would have configurations and components determined, in part, by the intended application and environment in which they are used. 
     DETAILED DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS 
     The following discussion and accompanying figures disclose various embodiments of a sole structure for an article of footwear. Concepts related to the sole structure are disclosed with reference to footwear having a configuration that is suitable for athletic activities, e.g., the sport of basketball. However, the sole structure may be applied to a wide range of athletic footwear styles, including tennis shoes, football shoes, cross-training shoes, walking shoes, soccer shoes, and hiking boots, for example. The sole structure may also be applied to footwear styles that are 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 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. 
     An article of footwear  10  is depicted in  FIGS. 1 and 2  as including an upper  12  and a sole assembly  14 . For reference purposes, footwear  10  may be divided into three general portions: a forefoot portion  16 , a midfoot portion  18 , and a heel portion  20 , as shown in  FIGS. 1 and 2 . Footwear  10  also includes a lateral side  22  and a medial side  24 . Forefoot portion  16  generally includes portions of footwear  10  corresponding with the toes and the joints connecting the metatarsals with the phalanges. Midfoot portion  18  generally includes portions of footwear  10  corresponding with the arch area of the foot, and heel portion  20  corresponds with rear portions of the foot, including the calcaneus bone. Lateral side  22  and medial side  24  extend through each of portions  16 - 20  and correspond with opposite sides of footwear  10 . Portions  16 - 20  and sides  22 - 24  are not intended to demarcate precise areas of footwear  10 . Rather, portions  16 - 20  and sides  22 - 24  are intended to represent general areas of footwear  10  to aid in the following discussion. In addition to footwear  10 , portions  16 - 20  and sides  22 - 24  may also be applied to upper  12 , sole assembly  14 , and individual elements thereof. 
     The figures illustrate only the article of footwear intended for use on the right foot of a wearer. One skilled in the art will recognize that a left article of footwear, such article being the mirror image of the right, is intended to fall within the scope of the present invention. 
     Unless otherwise stated, or otherwise clear from the context below, directional terms used herein, such as rearwardly, forwardly, inwardly, downwardly, upwardly, etc., refer to directions relative to footwear  10  itself. Footwear  10  is shown in  FIG. 1  to be disposed substantially horizontally, as it would be positioned on a horizontal surface when worn by a wearer. However, it is to be appreciated that footwear  10  need not be limited to such an orientation. Thus, in the illustrated embodiment of  FIG. 1 , rearwardly is toward heel portion  20 , that is, to the right as seen in  FIG. 1 . Naturally, forwardly is toward forefoot portion  16 , that is, to the left as seen in  FIG. 1 , and downwardly is toward the bottom of the page as seen in  FIG. 1 . Inwardly is toward the center of footwear  10 , and outwardly is toward the outer peripheral edge of footwear  10 . 
     Upper  12  forms an interior void that comfortably receives a foot and secures the position of the foot relative to sole assembly  14 . The configuration of upper  12 , as depicted, is suitable for use during athletic activities that involve running. Accordingly, upper  12  may have a lightweight, breathable construction that includes multiple layers of leather, textile, polymer, and foam elements adhesively bonded and stitched together. For example, upper  12  may have an exterior that includes leather elements and textile elements for resisting abrasion and providing breathability, respectively. The interior of upper  12  may have foam elements for enhancing the comfort of footwear  10 , and the interior surface may include a moisture-wicking textile for removing excess moisture from the area immediately surrounding the foot. 
     Sole assembly  14  may be secured to upper  12  by an adhesive, or any other suitable fastening means. Sole assembly  14 , which is generally disposed between the foot of the wearer and the ground, provides attenuation of ground reaction forces (i.e., imparting cushioning), traction, and may control foot motions, such as pronation. As with conventional articles of footwear, sole assembly  14  includes an insole (not shown) located within upper  12 , a midsole  26 , and an outsole  28 . Midsole  26  is attached to upper  12  and functions as the primary shock-attenuating and energy-absorbing component of footwear  10 . Outsole  28  is attached to the lower surface of midsole  26  by adhesive or other suitable means. Suitable materials for outsole  28  include traditional rubber materials. Other suitable materials for outsole  28  will become readily apparent to those skilled in the art, given the benefit of this disclosure. In certain embodiments, sole assembly  14  may not include an outsole layer separate from midsole  26  but, rather, the outsole may comprise a bottom surface of midsole  26  that provides the external traction surface of sole assembly  14 . 
     Upper  12  is depicted as having a substantially conventional configuration that incorporates a plurality material elements (e.g., textiles, foam, leather, and synthetic leather) 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  12  in order to selectively impart properties of durability, air-permeability, wear-resistance, flexibility, and comfort, for example. The material elements form a structure that defines an interior void for receiving the foot. An ankle opening  30  in heel portion  20  provides access to the interior void. In addition, upper  12  may include a lace  32  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  32  may extend through apertures in upper  12 , and a tongue portion of upper  12  may extend between the interior void and lace  32 . Given that various aspects of the present application primarily relate to sole assembly  14 , upper  12  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  12  may vary significantly within the scope of the present invention. 
     Sole assembly  14  includes an upper plate  34  secured to a lower surface of midsole  26 . A lower plate  36  includes a plurality of lower plate arms  38  that curve downwardly from upper plate  34 . In the illustrated embodiment, lower plate arms  38  curve downwardly and outwardly from upper plate  34  such that they are substantially concave with respect to upper plate  34 . 
     Each lower plate arm  38  is spaced from adjacent lower plate arm  38  by a slot  40  formed in lower plate  36 . Lower plate  36  is seen in  FIG. 2  with outsole  28  not shown for clarity purposes. 
     In certain embodiments lower plate  36  includes a first lateral lower plate arm  38 A positioned in a front portion of forefoot portion  16  of sole assembly  14 . A second lateral lower plate arm  38 B is positioned in a central portion of forefoot portion  16  of sole assembly  14 . A third lateral lower plate arm  38 C is positioned in a rear portion of forefoot portion  16  of sole assembly  14 . 
     Similarly, lower plate  36  includes a first medial lower plate arm  38 D positioned in a front portion of forefoot portion  16  of sole assembly  14 . A second medial lower plate arm  38 E is positioned in a central portion of forefoot portion  16  of sole assembly  14 . A third medial lower plate arm  38 F is positioned in a rear portion of forefoot portion  16  of sole assembly  14 . 
     In certain embodiments, lower plate  36  and upper plate  34  are of unitary, that is, one-piece, construction. Upper plate  34  and lower plate members  36  may be formed of any number of materials including glass-filled nylon, carbon-filled materials, polyamides such as Aramid, produced by Dupont, and a poly-paraphenylene terephthalamides such as Kevlar®, produced by Dupont, a polyether block copolyamide (sold as Pebax® by ATOFINA Chemicals of Philadelphia, Pa.), a blend of a polyether block copolyamide with another material (such as glass-filled nylon, carbon-filled materials, polyamides, or poly-paraphenylene terephthalamides), thermoplastic polyurethane (TPU), or other materials. Such materials are advantageously cut resistant and provide good dimensional stability for sole assembly  14 . 
     Outsole  28  may be formed of a plurality of outsole portions  28 A, each of which is secured to a lower surface of a corresponding lower plate arm  36 A-F, as seen in  FIG. 1 . 
     In the illustrated embodiment, heel portion  20  of sole assembly  14  includes a pivot element  33  including an upper support  35  connected to a lower support  37  by way of a coupling  39 . Coupling  39  allows upper support  35  to pivot with respect to lower support  37 . It is to be appreciated that heel portion  20  may have a more conventional configuration in other embodiments. 
     Another embodiment of footwear  10  is shown in  FIG. 4 , in which a first lateral insert  42  is provided between upper plate  34  and first, second, and third medial lower plate arms  38 D, E, F. Similarly a second medial insert  44  is provided between upper plate  34  and first, second, and third lateral lower plate arms  38 A, B, C. Lateral insert  42  and medial insert  44  may be formed of an air bladder, an elastomer, or a foam material, for example, and serve to provide additional support and cushioning for sole assembly  14 . 
     Another embodiment of footwear  10  is shown in  FIG. 4 , in which upper plate  34  is formed of a first front portion  34 A positioned in a front portion of forefoot portion  16  of sole assembly  14 , a second central portion  34 B spaced slightly rearwardly from front portion  34 A and positioned in a central portion of forefoot portion  16  of sole assembly  14 , and a third rear portion  34 C spaced slightly rearwardly from middle portion  34 B and positioned in a rear portion of forefoot portion  16  of sole assembly  14 . Lateral lower plate arms  38 A,  38 B, and  38 C extend from front portion  34 A, central portion  34 B, and rear portion  34 C, respectively, of upper plate  34 . Medial lower plate arms  38 D,  38 E, and  38 F extend from front portion  34 A, central portion  34 B, and rear portion  34 C, respectively, of upper plate  34 . In such an embodiment, with upper plate  34  formed of three separate and distinct portions, with accompanying lower plate arms, forefoot portion  16  of footwear  10  can more easily bend and flex, thereby enhancing comfort and flexibility of footwear  10 . 
     In certain embodiments, as seen in  FIG. 3 , upper plate  34  and lower plate arms  38 A-E are of unitary construction. It other embodiments, as seen in  FIG. 6 , upper plate and lower plate arms  38 A-E may be separate elements secured to one another with adhesive or other suitable fastening means. 
     Another embodiment is shown in  FIG. 7 . In this embodiment, upper plate  34  includes a plurality of upper plate arms  46  and lower plate  36  includes a plurality of lower plate arms  48 . In this embodiment, lower plate arms  48  curve outwardly and downwardly from upper plate  34  such that lower plate arms  48  are substantially convex with respect to upper plate  34 . Upper plate arms  46  and lower plate arms  48  are staggered, or offset, with respect to one another such that no upper plate arm  46  is positioned above a lower plate arm  48  and vice versa. 
     In the illustrated embodiment, midsole  26  includes a first portion  26 A positioned above upper plate  34  and a second portion  26 B positioned below lower plate arms  48 . It can be seen that in this embodiment, second portion  26 B has been cut away between adjacent lower plate arms  48 . Additionally, in this embodiment, upper plate arms  46  and lower plate arms  48  extend along substantially the entire length of sole assembly  14 . It is to be appreciated that upper plate arms  46  and lower plate arms  48  can be positioned at any location along sole assembly  14 . 
     It is to be appreciated that the upper and lower plate arms can be modified to optimize performance and comfort. The material, thickness, degree of curvature, length or any other aspects of the geometry of the arms can be altered to affect their performance. For example, in certain embodiments, as seen in  FIG. 7 , a first rib  50  extends along an upper surface of each lower plate arm  48  and a second rib  52  extends along a lower surface of each upper plate arm  46 . It is to be appreciated that in certain embodiments, a first rib  50  may be provided on one or more but not all of lower plate arms  48 , and that a second rib  52  may be provided on one or more but not all of upper plate arms  46 . 
     It is to be appreciated that the embodiment illustrated in  FIG. 7  may be constructed such that upper plate  34  is common to both upper plate arms  46  and lower plate arms  48 , as seen in  FIG. 9 . In such an embodiment, upper plate  34  could alternatively be referred to simply as a plate, and upper plate arms  46  and lower plate arms  48  could alternatively be referred to as upper arms and lower arms, respectively. As can be seen  FIGS. 7 &amp; 9 , the upper and lower arms  46 ,  48  alternately curve upwardly and downwardly from the plate, in butterfly fashion. 
     Another embodiment is shown in  FIG. 8 , which is similar to the embodiment shown in  FIG. 7 , with one exception. In the embodiment of  FIG. 8 , lower portion  26 B of midsole  26 B is not cut away between adjacent lower plate arms  48 , but, rather, is a contiguous midsole along the length of sole assembly  14 . 
     The spring-like action of the arms of sole assembly  14 , which are pre-flexed in a curved condition, helps a user change direction and cut when using footwear  10 , thereby improving propulsion for the user. The curvature of the arms helps to relieve stress encountered during use of footwear  10 . The arms of sole assembly  14  provide independent suspension for running on uneven surfaces, and provide a more stable ride for the foot as the independent elements adapt to the uneven terrain. 
     Another embodiment is shown in  FIG. 10 , in which upper plate  34  could be referred to simply as a plate  34 , and upper plate arms  46  and lower plate arms  48  could alternatively be referred to as upper arms  46  and lower arms  48 , respectively. Plate  34  includes a spine  54  to which each of upper arms  46  and lower arms  48  are connected. Upper arms  46  extend outwardly and upwardly from spine  54 , and lower arms  48  extend outwardly and downwardly from spine  54 . Like that of the embodiment shown in  FIG. 7 , upper arms  46  and lower arms  48  are alternately positioned along lateral side  22  and medial side  24  of plate  34 . 
     Spine  54  has a longitudinal axis L that is curved when viewed from above. In certain embodiments, longitudinal axis L of spine  54  has compound curve shape, that is, it is curved in multiple directions. 
     In certain embodiments, at least one upper arm  46 ′ on lateral side  22  of plate  34  is opposed laterally from a corresponding lower arm  48 ′ on medial side  24  of plate  34 . In certain embodiments, at least one upper arm  46 ″ on medial side  24  of plate  34  is opposed laterally from a corresponding lower arm  48 ″ on lateral side  22  of plate  34 . 
     In light of the foregoing disclosure of the invention and description of various embodiments, those skilled in this area of technology will readily understand that various modifications and adaptations can be made without departing from the scope and spirit of the invention. All such modifications and adaptations are intended to be covered by the following claims.