Patent Publication Number: US-2023157412-A1

Title: Article of footwear having removable components

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of and priority to U.S. Provisional App. No. 63/282,018, filed on Nov. 22, 2021, which is herein incorporated by reference in its entirety. 
    
    
     REFERENCE REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable 
     SEQUENCE LISTING 
     Not applicable 
     BACKGROUND 
     1. Field of the Invention 
     The present disclosure relates generally to an article of footwear including a removable outsole. 
     2. Description of the Background 
     Many conventional shoes or other articles of footwear generally comprise an upper and a sole attached to a lower end of the upper. Conventional shoes further include an internal space, i.e., a void or cavity, which is created by interior surfaces of the upper and sole, that receives a foot of a user before securing the shoe to the foot. The sole is attached to a lower surface or boundary of the upper and is positioned between the upper and the ground. As a result, the sole typically provides stability and cushioning to the user when the shoe is being worn. In some instances, the sole may include multiple components, such as an outsole, a midsole, and an insole. The outsole may provide traction to a bottom surface of the sole, and the midsole may be attached to an inner surface of the outsole, and may provide cushioning or added stability to the sole. For example, a sole may include a particular foam material that may increase stability at one or more desired locations along the sole, or a foam material that may reduce stress or impact energy on the foot or leg when a user is running, walking, or engaged in another activity. The sole may also include additional components, such as plates, embedded with the sole to increase the overall stiffness of the sole and reduce energy loss during use. Further, the components of the sole are often permanently attached to each other using a joining process that involves an adhesive and/or compound, which requires substantial energy inputs and labor. In addition, the adhesive and/or compounds can limit the potential for recycling the shoe. 
     The upper generally extends upward from the sole and defines an interior cavity that completely or partially encases a foot. In most cases, the upper extends over the instep and toe regions of the foot, and across medial and lateral sides thereof. Many articles of footwear may also include a tongue that extends across the instep region to bridge a gap between edges of medial and lateral sides of the upper, which define an opening into the cavity. The tongue may also be disposed below a lacing system and between medial and lateral sides of the upper, to allow for adjustment of shoe tightness. The tongue may further be manipulable by a user to permit entry or exit of a foot from the internal space or cavity. In addition, the lacing system may allow a user to adjust certain dimensions of the upper or the sole, thereby allowing the upper to accommodate a wide variety of foot types having varying sizes and shapes. 
     The upper of many shoes may comprise a wide variety of materials, which may be utilized to form the upper and chosen for use based on one or more intended uses of the shoe. The upper may also include portions comprising varying materials specific to a particular area of the upper. For example, added stability may be desirable at a front of the upper or adjacent a heel region so as to provide a higher degree of resistance or rigidity. In contrast, other portions of a shoe may include a soft woven textile to provide an area with stretch-resistance, flexibility, air-permeability, or moisture-wicking properties. 
     However, in many cases, articles of footwear having sole structures with an increased comfort and better fit are desired, along with soles having improved cushioning systems or structural characteristics. In addition, articles of footwear are desired that are manufactured according to more efficient manufacturing methods and more easily recycled. 
     SUMMARY 
     An article of footwear, as described herein, may have various configurations. The article of footwear may have an upper and a sole structure connected to the upper. 
     In one aspect, an interlocking assembly for an article of footwear includes a first component having a plurality of ribs and a second component having a plurality of receptacles. The plurality of ribs of the first component are configured to be received within the plurality of receptacles of the second component to removably attach the first component and the second component. In some embodiments, at least one of the plurality of receptacles is exposed through a lower surface of the second component. In some embodiments, the plurality of receptacles is located between the lower surface and a top surface of the second component. In some embodiments, the plurality of receptacles is located between a medial side and a lateral side of the second component. In some embodiments, the plurality of ribs extends from a heel region to a midfoot region of the first component. In some embodiments, the first component is formed of a different material than the second component. In some embodiments, the first component is configured to snap into the second component. 
     In another aspect, a sole structure for an article of footwear includes a midsole and an outsole. The outsole includes a plurality of ribs that are configured to be received within a portion of the midsole. In some embodiments, the plurality of ribs are disposed within a heel region the plurality of ribs are exposed through a lateral side and a medial side of the midsole. In some embodiments, one or more of the plurality of ribs includes a cavity. In some embodiments, one or more of the plurality of ribs extends from a lateral side to a medial side of the midsole. In some embodiments, each rib of the plurality of ribs is configured to removably retain the outsole against the midsole. 
     In still another aspect, an interlocking assembly for an article of footwear includes a midsole having a flange that includes a securing feature and an outsole having a chamber that is at least partially defined by a clip extending from a heel end of the outsole. The flange is configured to be received within the chamber in an assembled configuration. In addition, the securing feature is configured to be removably engaged with the clip in the assembled configuration. In some embodiments, a through hole is at least partially defined by the clip and configured to receive the securing feature in the assembled configuration. In some embodiments, the securing feature includes a first block extending from a lateral side of the flange and a second block extending from a medial side of the flange. In some embodiments, the clip extends from a top surface of the outsole and between a medial side and a lateral side of a rib to at least partially define the chamber. In some embodiments, the rib includes a rounded head extending from a curved base, a cavity extending through the head, and a slot extending through the base. Additionally, the flange at least partially defines a receptacle of the midsole and the head of the rib is configured to fit within the receptacle of the midsole in the assembled configuration. In some embodiments, the outsole and the midsole are configured to be flexed away from one another during disassembly of the interlocking assembly. 
     Other aspects of the article of footwear, including features and advantages thereof, will become apparent to one of ordinary skill in the art upon examination of the figures and detailed description herein. Therefore, all such aspects of the article of footwear are intended to be included in the detailed description and this summary. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of a bottom and medial side of an article of footwear configured as a right shoe that includes an upper and a sole structure, according to an embodiment of the disclosure; 
         FIG.  2    is a schematic representation of a cross-sectional view of an outsole; 
         FIG.  3    is a schematic representation of a cross-sectional view of a midsole; 
         FIG.  4    is a schematic representation of a cross-sectional view of an interlocking assembly for a sole structure including the midsole of  FIG.  3    and the outsole of  FIG.  2   , the interlocking assembly being depicted in an assembled configuration; 
         FIG.  5    is a partial medial side view of another embodiment of an interlocking assembly for a sole structure including a midsole and an outsole, the interlocking assembly being depicted in a partially assembled configuration; 
         FIG.  6    is a partial lateral side view of the interlocking assembly of  FIG.  5   , the interlocking assembly being depicted in an assembled configuration; 
         FIG.  7    is a partial top view of another embodiment of an interlocking assembly for a sole structure including a midsole and an outsole, the interlocking assembly being depicted in an assembled configuration; and 
         FIG.  8    is a partial medial side view of still another embodiment of an interlocking assembly for a sole structure including a midsole and an outsole, the interlocking assembly being depicted in an assembled configuration; 
         FIG.  9    is a schematic representation of a top plan view of another embodiment of an outsole; 
         FIG.  10    is a schematic representation of a side view of a portion of another embodiment of still an outsole; 
         FIG.  11    is a schematic representation of a top perspective view of another embodiment of an outsole; 
         FIG.  12    is a schematic representation of a bottom perspective view of the outsole of  FIG.  11   ; 
         FIG.  13    is a schematic representation of a top perspective view of another embodiment of a midsole; 
         FIG.  14    is a schematic representation of a bottom perspective view of the midsole of  FIG.  13   ; 
         FIG.  15    is a partial representation of a side view of another embodiment of an interlocking assembly in an assembled configuration, the interlocking assembly comprising the outsole of  FIGS.  11  and  12    and the midsole of  FIGS.  13  and  14   ; and 
         FIG.  16    is a partial representation of a rear view of the interlocking assembly of  FIG.  15    being attached to an upper. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     The following discussion and accompanying figures disclose various embodiments or configurations of a shoe and a sole structure. Although embodiments of a shoe or sole structure are disclosed with reference to a sports shoe, such as a running shoe, tennis shoe, basketball shoe, etc., concepts associated with embodiments of the shoe or the sole structure may be applied to a wide range of footwear and footwear styles, including cross-training shoes, football shoes, golf shoes, hiking shoes, hiking boots, ski and snowboard boots, soccer shoes and cleats, walking shoes, and track cleats, for example. Concepts of the shoe or the sole structure may also be applied to articles of footwear that are considered non-athletic, including dress shoes, sandals, loafers, slippers, and heels. In addition to footwear, particular concepts described herein may also be applied and incorporated in other types of apparel or other athletic equipment, including helmets, padding or protective pads, shin guards, and gloves. Even further, particular concepts described herein may be incorporated in cushions, backpack straps, golf clubs, or other consumer or industrial products. Accordingly, concepts described herein may be utilized in a variety of products. 
     The term “about,” as used herein, refers to variation in the numerical quantity that may occur, for example, through typical measuring and manufacturing procedures used for articles of footwear or other articles of manufacture that may include embodiments of the disclosure herein; through inadvertent error in these procedures; through differences in the manufacture, source, or purity of the ingredients used to make the compositions or mixtures or carry out the methods; and the like. Throughout the disclosure, the terms “about” and “approximately” refer to a range of values ± 5% of the numeric value that the term precedes. 
     The present disclosure is directed to an article of footwear and/or specific components of the article of footwear, such as an upper and/or a sole or sole structure. The upper may comprise a knitted component, a woven textile, and/or a non-woven textile. The knitted component may be made by knitting of yarn, the woven textile by weaving of yarn, and the non-woven textile by manufacture of a unitary non-woven web. Knitted textiles include textiles formed by way of warp knitting, weft knitting, flat knitting, circular knitting, and/or other suitable knitting operations. The knit textile may have a plain knit structure, a mesh knit structure, and/or a rib knit structure, for example. Woven textiles include, but are not limited to, textiles formed by way of any of the numerous weave forms, such as plain weave, twill weave, satin weave, dobbin weave, jacquard weave, double weaves, and/or double cloth weaves, for example. Non-woven textiles include textiles made by air-laid and/or spun-laid methods, for example. The upper may comprise a variety of materials, such as a first yarn, a second yarn, and/or a third yarn, which may have varying properties or varying visual characteristics. 
       FIG.  1    depicts an exemplary embodiment of an article of footwear  100  including an upper  102  and a sole structure  104 . The upper  102  is attached to the sole structure  104  and together define an interior cavity (not shown) into which a foot may be inserted. For reference, the article of footwear  100  defines a forefoot region  108 , a midfoot region  110 , and a heel region  112 . The forefoot region  108  generally corresponds with portions of the article of footwear  100  that encase portions of the foot that includes the toes, the ball of the foot, and j oints connecting the metatarsals with the toes or phalanges. The midfoot region  110  is proximate and adjoining the forefoot region  108 , and generally corresponds with portions of the article of footwear  100  that encase the arch of foot, along with the bridge of the foot. The heel region  112  is proximate and adjoining the midfoot region  110  and generally corresponds with portions of the article of footwear  100  that encase rear portions of the foot, including the heel or calcaneus bone, the ankle, and/or the Achilles tendon. 
     Many conventional footwear uppers are formed from multiple elements (e.g., textiles, polymer foam, polymer sheets, leather, and synthetic leather) that are joined through bonding or stitching at a seam. In some embodiments, the upper  102  of the article of footwear  100  is formed from a knitted structure or knitted components. In various embodiments, a knitted component may incorporate various types of yarn that may provide different properties to an upper. For example, one area of the upper  102  may be formed from a first type of yarn that imparts a first set of properties, and another area of the upper  102  may be formed from a second type of yarn that imparts a second set of properties. Using this configuration, properties of the upper  102  may vary throughout the upper  102  by selecting specific yarns for different areas of the upper  102 . 
     The article of footwear  100  also includes a medial side  116  and a lateral side  118 . In particular, the lateral side  118  corresponds to an outside portion of the article of footwear  100  and the medial side  116  corresponds to an inside portion of the article of footwear  100 . As such, left and right articles of footwear have opposing lateral and medial sides, such that the medial sides  116  are closest to one another when a user is wearing the articles of footwear  100 , while the lateral sides  118  are defined as the sides that are farthest from one another while being worn. The medial side  116  and the lateral side  118  adjoin one another at opposing, distal ends of the article of footwear  100 , although other configurations are possible. 
     The article of footwear  100  further includes a toe end  122  and a heel end  124 . In particular, the toe end  122  corresponds to a front-most portion of the article of footwear  100  and the heel end  124  corresponds to a rear-most portion of the article of footwear  100 . As such, the toe end  122  and the heel end  124  are disposed at opposing ends of the article of footwear  100 . In some embodiments, the toe end  122  is disposed within the forefoot region  108  and the heel end  124  is disposed within the heel region  112 , although other configurations are possible. 
     Unless otherwise specified, the forefoot region  108 , the midfoot region  110 , the heel region  112 , the medial side  116 , and the lateral side  118  are intended to define boundaries or areas of the article of footwear  100 . To that end, the forefoot region  108 , the midfoot region  110 , the heel region  112 , the medial side  116 , and the lateral side  118  generally characterize sections of the article of footwear  100 . Further, both the upper  102  and the sole structure  104  may be characterized as having portions within the forefoot region  108 , the midfoot region  110 , the heel region  112 , and on the medial side  116  and the lateral side  118 . Therefore, the upper  102  and the sole structure  104 , and/or individual portions of the upper  102  and the sole structure  104 , may include portions thereof that are disposed within the forefoot region  108 , the midfoot region  110 , the heel region  112 , and on the medial side  116  and the lateral side  118 . 
     The sole structure  104  is connected or secured to the upper  102  and extends between a foot of a user and the ground when the article of footwear  100  is worn by the user. The sole structure  104  may include one or more components, which may include an outsole, a midsole, a heel, a vamp, and/or an insole. For example, in some embodiments, a sole structure may include an outsole that provides structural integrity to the sole structure, along with providing traction for a user, a midsole that provides a cushioning system, and an insole that provides support for an arch of a user. As will be further discussed herein, the sole structure  104  of the present embodiment of the invention includes one or more components that provide the sole structure  104  constructed with a removable outsole. 
     In the illustrated embodiment, the sole structure  104  includes an outsole  130  and a midsole  134 . The outsole  130  may define a bottom end or bottom surface  140  of the sole structure  104  across the heel region  112 , the midfoot region  110 , and the forefoot region  108 . Further, the outsole  130  may include a ground-engaging portion or include a ground-engaging surface of the sole structure  104  and may be opposite of the insole thereof. As illustrated in  FIG.  1   , the bottom surface  140  of the outsole may include a tread pattern  144  that can include a variety of shapes and configurations. The outsole  130  may be formed from one or more materials to impart durability, wear-resistance, abrasion resistance, or traction to the sole structure  104 . In some embodiments, the outsole  130  may be formed from any kind of elastomer material, e.g., rubber, including thermoset elastomers or thermoplastic elastomers, or a thermoplastic material, e.g., thermoplastic polyurethane (TPU). In some embodiments, the outsole  130  may define a shore A hardness up to 95. In addition, the outsole  130  may be manufactured by a process involving injection molding, vulcanization, printing layer by layer, i.e., additive manufacturing systems or methods, and the like. 
     Still referring to  FIG.  1   , the midsole  134  may be individually constructed from a thermoplastic material, such as polyurethane (PU), for example, and/or an ethylene-vinyl acetate (EVA), copolymers thereof, or a similar type of material. In other embodiments, the midsole  134  may be an EVA-Solid-Sponge (“ESS”) material, an EVA foam (e.g., PUMA® ProFoam Lite™, IGNITE Foam), polyurethane, polyether, an olefin block copolymer, organosheets, a thermoplastic material (e.g., a thermoplastic polyurethane, a thermoplastic elastomer, a thermoplastic polyolefin, etc.), or a supercritical foam. The midsole  134  may be a single polymeric material or may be a blend of materials, such as an EVA copolymer, a thermoplastic polyurethane, a polyether block amide (PEBA) copolymer, and/or an olefin block copolymer. One example of a PEBA material is PEBAX®. In some embodiments, the midsole  134  is manufactured by a process involving injection molding, vulcanization, printing layer by layer, i.e., additive manufacturing systems or methods, and the like. 
     In embodiments where the midsole  134  is formed from a supercritical foaming process, the supercritical foam may comprise micropore foams or particle foams, such as a TPU, EVA, PEBAX®, or mixtures thereof, manufactured using a process that is performed within an autoclave, an injection molding apparatus, or any sufficiently heated/pressurized container that can process the mixing of a supercritical fluid (e.g., CO 2 , N 2 , or mixtures thereof) with a material (e.g., TPU, EVA, polyolefin elastomer, or mixtures thereof) that is preferably molten. During an exemplary process, a solution of supercritical fluid and molten material is pumped into a pressurized container, after which the pressure within the container is released, such that the molecules of the supercritical fluid rapidly convert to gas to form small pockets within the material and cause the material to expand into a foam. In further embodiments, the midsole  134  may be formed using alternative methods known in the art, including the use of an expansion press, an injection machine, a pellet expansion process, a cold foaming process, a compression molding technique, die cutting, or any combination thereof. For example, the midsole  134  may be formed using a process that involves an initial foaming step in which supercritical gas is used to foam a material and then compression molded or die cut to a particular shape. 
     In the illustrated embodiment of  FIG.  1   , the sole structure  104  is provided as an interlocking assembly in which a first component, such as the outsole  130 , and a second component, such as the midsole  134 , are removably coupled to one another by mechanical attachment features, as will be described in more detail throughout this disclosure. With reference to  FIG.  1   , a central axis C extends vertically through the article of footwear  100  within the midfoot region  110  and a longitudinal axis L extends horizontally, i.e., perpendicular to the central axis C, along the outsole  130  and intersects the toe end  122  and the heel end  124  of the article of footwear  100 . To that end, at least a portion of the bottom surface  140  of the outsole  130  is tangent or otherwise coincident with a longitudinal plane defined by the longitudinal axis L. In some embodiments, the outsole  130  and the midsole  134  are each curved or bowed in a vertical direction parallel with the central axis C and, as a result, the outsole  130  may define concave or convex curvatures relative to the longitudinal plane of the longitudinal axis L. 
       FIG.  2    illustrates a schematic representation of a cross-sectional view of an embodiment of an outsole  150  that includes a top surface  154  that is opposite a bottom surface  158  and extends between a toe end  162  and a heel end  166 . Further, the outsole  150  includes attachment features in the form of ribs  174 . In particular, each of the ribs  174  includes a head  178  that is connected to a base  182  by a stem  186 . The base  182  is positioned on the top surface  154  of the outsole  150  and defines an interface between each rib  174  and the top surface  154  of the outsole  150 . As illustrated in  FIG.  2   , the ribs  174  are provided as a plurality including ribs  174 A,  174 B,  174 C, and  174 D, labeled in sequential order moving in a toe-to-heel direction, i.e., heel-ward. Accordingly, the ribs  174  include the most toe-ward rib  174 A, i.e., spaced farthest from heel end  166  of the outsole  150 , and the most heel-ward rib  174 D, i.e., located closest to the heel end  166  of the outsole  150 , and the ribs  174 B and  174 C are located therebetween. In some embodiments, greater or fewer ribs  174  are provided. For purposes of clarity, it will be appreciated that the ribs  174 A-D may be referred to herein individually or collectively as rib(s)  174 . 
     In the illustrated embodiment, the base  182  of each rib  174  narrows from the top surface  154  to the stem  186  of each rib  174 , such that the base  182  is wider, i.e., dimension in a horizontal direction, than the stem  186  and, in particular, the base  182  curves between the top surface  154  and the stem  186 . In this way, the base  182  provides stability for each rib  174 , which allows for bending of each rib  174  about each base  182  in toe-ward or heel-ward directions. 
     With continued reference to  FIG.  2   , the head  178  is connected to the stem  186  opposite the base  182 . In some embodiments, the head  178  extends outwardly from the stem  186  in both vertical and horizontal directions. In some embodiments, the head  178  is wider and taller, i.e., dimension H1 measured in the vertical direction between the head  178  and the bottom surface  158 , than the stem  186 . In the illustrated embodiment, the head  178  is provided as having a generally rounded or circular cross-sectional shape, although the head  178  may be sized and shaped differently. For example, the head  178  may define a rectangular, triangular, elliptical, trapezoidal, conical, frustoconical, pyramidal, frustopyramidal, alphabetical, numerical, pictogram, logogram, ideogram, or any irregular cross-sectional shape, among others. 
     Further, the stem  186  extends away from the head  178  to define a projection axis P. For purposes of clarity, the projection axis P is illustrated only for the rib  174 A; however, it will be understood that each rib  174  includes a projection axis P defined along the stem  186 . As depicted in  FIG.  2   , the projection axis P forms an angle θ relative to the longitudinal axis L, such that the rib  174 A extends at the angle θ relative to the longitudinal axis L. In some embodiments, the ribs  174  are disposed orthogonally with respect to the longitudinal axis L. In the illustrated embodiment, the rib  174 A extends at an angle θ that is less than 90 degrees, although other configurations are possible. For example, two or more of the ribs  174  can extend parallel with each other at an angle θ that is greater than 90 degrees. Alternatively, two or more of the ribs  174  can extend at varying angles θ. 
     Still referring to  FIG.  2   , the projection axis P extends through a center of the head  178  of the rib  174 , such that the head  178  is generally centered on the projection axis P and, thus, the head  178  is generally centered on the stem  186 . In some embodiments, the head  178  is offset relative to the stem  186  and the projection axis P. For example, the head  178  may extend substantially toe-ward of the stem  186 , such that the head  178  is substantially disposed toe-ward of the projection axis P. Alternatively, the head  178  can extend substantially heel-ward of the stem  186 , such that the head  178  is substantially disposed heel-ward of the projection axis P. The location of the head  178  relative to the stem  186  impacts cushioning and/or stiffness performance properties of the rib  174  and/or the outsole  150 . 
     With continued reference to  FIG.  2   , each rib  174  is partially hollow in that the head  178  includes a cavity  190  extending partially or entirely through the head  178  in a lateral-to-medial direction. In some embodiments, the cavity  190  is empty, although other configurations are possible. It is contemplated that the cavity  190  may be partially or entirely filled with a fluid, gas, liquid, bead-like particles, foams, bio-degradeable materials, bacteria, spring members, or dampening members, among others. In some embodiments, the cavity  190  is open and exposed on the lateral side  118  or the medial side  116  of the footwear  100 . The cavity  190  may be interrupted or, instead, the cavity  190  may extend continuously through the entire extent of the head  178 . In some examples, the cavity  190  may extend into or communicate with the stem  186 , the base  182 , and the bottom surface  158  of the outsole  150 . For example, the cavity  190  may extend from the head  178  through the stem  186  to be exposed at the bottom surface  158  of the outsole  150 . In this way, the cavity  190  can perform several functions including, e.g., a sound chamber, an air vent or pathway, a negative space that reduces weight and/or density, and an aesthetic features, among others. 
     As illustrated in  FIG.  2   , the ribs  174  are located in the heel region  112  of the footwear  100  and define an outsole attachment region  194  of the outsole  150 . The outsole attachment region  194  forms a boundary or periphery that surrounds the ribs  174  and, thus, the outsole attachment region  194  defines an area or surface area. In some embodiments, the outsole attachment region  194  comprises less than 50% of a total surface area of the top surface  154  of the outsole  150 . It is contemplated that the outsole attachment region  194  comprises greater than 50% of the total area of the top surface  154 . In addition, the ribs  174  can be located in the forefoot region  108  and the midfoot region  110 , such that the outsole attachment region  194  is located within the forefoot region  108  and the midfoot region  110 . It is further contemplated that multiple outsole attachment regions may be defined by discrete sets or groupings of ribs, as will be described below. 
     Staying with  FIG.  2   , the ribs  174  are spaced apart from one another to form gaps  198  between the ribs  174  and across the top surface  154  of the outsole  150 . The gaps  198  are sized and shaped in accordance with the ribs  174 , such that the gaps  198  can be enlarged or minimized by changing a size or shape of the ribs  174  or by changing a spacing, i.e., a distance, between each of the ribs  174 . The ribs  174  are spaced apart varying distances, such as the relatively larger distance between the rib  174 C and the rib  174 D. Further, the ribs  174  of the present embodiment are depicted in cross-sectional view but it shall be appreciated that the ribs  174  extend at least partially between the lateral side  118  and the medial side  116  of footwear  100  (see  FIG.  1   ). In some embodiments, the ribs  174  extend continuously between the lateral side  118  and the medial side  116  of the footwear  100 , although other configurations are possible. It is contemplated that one or more of the ribs  174  is provided as a set or array of discrete portions that may be identical to one another or differently shaped from one another and that are spaced apart from one another in a lateral-to-medial or medial-to-lateral direction. It is further contemplated that one or more of the ribs  174  are provided as varying dimensionally in a vertical or horizontal direction between the lateral side  118  and the medial side  116  of the footwear  100 . Further, it is contemplated that the ribs  174  may be provided as curved concavely or convexly relative to the central plane of the central axis C. 
     With continued reference to  FIG.  2   , the outsole  150  is curved or bowed relative to the longitudinal plane of the longitudinal axis L. In the illustrated embodiment, the outsole  150  curves away from the longitudinal plane at the toe end  162  and the heel end  166  and also within the midfoot region  110 . To that end, the outsole  150  is convexly curved in the forefoot region  108  and the heel region  112  and concavely curved in the midfoot region  110 . It is contemplated that the outsole  150  is concavely or convexly curved in other directions, such as between the lateral side  118  and the medial side  116  (see  FIG.  1   ). 
       FIG.  3    illustrates a schematic, sectional view of a midsole  230  that includes an upper surface  234  opposite a lower surface  238  and extends between a toe end  242  and a heel end  246 . In the illustrated embodiment, a plurality of ridges  250  are formed in the upper surface  234  within the forefoot region  108  and a rim  254  extends from the upper surface  234  within the heel region  112  proximate to the heel end  246 . The midsole  230  varies in height H2 between the toe end  242  and the heel end  246 , such that the midsole  230  is shorter within the forefoot region  108  than within the heel region  112 , although other configurations are possible. 
     As illustrated in  FIG.  3   , apertures  258  are formed in the lower surface  238  of the midsole  230 . In the illustrated embodiment, the apertures  258  communicate with respective receptacles  262  that are formed internally within the midsole  230  between the lower surface  238  and the upper surface  234 . Each receptacle  262  is defined by an interior surface  266  of the midsole  230  to form a generally rounded or circular cross-sectional shape, such that the receptacles  262  are configured to receive the ribs  174  in an assembled configuration (see  FIG.  4   ). Accordingly, the receptacles  262  are provided as any size and shape to correspond to the ribs  174 . In the illustrated embodiment of  FIG.  3   , the receptacles  262  are a plurality including receptacles  262 A,  262 B,  262 C,  262 D, labeled in sequential order moving in a toe-to-heel direction, i.e., heel-ward. Accordingly, the receptacles  262  include the most toe-ward receptacle  262 A, i.e., spaced farthest from the heel end  246  of the midsole  230 , and the most heel-ward receptacle  262 D, i.e., located closest to the heel end  246  of the midsole  230 , and the receptacles  262 B and  262 C are located therebetween. To that end, the apertures  258  are a plurality including apertures  258 A that corresponds to the receptacle  262 A, aperture  258 B that corresponds to the receptacle  262 B, aperture  258 C that corresponds to the receptacle  262 C, and aperture  258 D that corresponds to the receptacle  262 D. For purposes of clarity, it will be appreciated that the receptacles  262 A-D may be referred to herein individually or collectively as receptacle(s)  262  and, also, that the apertures  258 A-D may be referred to herein individually or collectively as aperture(s)  258 . 
     Further, as illustrated in  FIG.  3   , the receptacles  262  are open and exposed through the lower surface  238  by the respective apertures  258 , and the apertures  258  are relatively narrower than the receptacles  262 . In particular, the apertures  258  are at least partially defined by flanges  270  of the midsole  230 . The flanges  270  are provided in opposing pairs at the lower surface  238  of the midsole  230  to form the apertures  258  therebetween, such that a pair of flanges  270  extend inwardly toward each other without contacting one another. The flanges  270  vary in size and shape to resiliently engage with the ribs  174  of the outsole  150 . Further, the flanges  270  are configured to fit within the gaps  198  of the outsole  150  when in an assembled configuration (see  FIG.  4   ). Accordingly, the flanges  270  are generally L-shaped members, although other configurations are possible. 
     As illustrated in  FIG.  3   , the receptacles  262  are located in the heel region  112  of the footwear  100  and define a midsole attachment region  274  of the midsole  230  that is configured to correspond to the outsole attachment region  194  of the outsole  150 . The midsole attachment region  274  forms a boundary or periphery that surrounds the receptacles  262  and, thus, the midsole attachment region  274  defines an area or surface area. In some embodiments, the midsole attachment region  274  comprises less than 50% of a total surface area of the lower surface  238  of the midsole  230 . It is contemplated that the midsole attachment region  274  comprises greater than 50% of the total area of the lower surface  238 . In addition, the receptacles  262  can be located in the forefoot region  108  and the midfoot region  110 , such that the midsole attachment region  274  is located within the forefoot region  108  and the midfoot region  110 . It is further contemplated that multiple midsole attachment regions may be defined by discrete sets or groupings of receptacles, as will be described below. 
     With continued reference to  FIG.  3   , the midsole  230  is curved or bowed relative to the longitudinal plane of the longitudinal axis L. In the illustrated embodiment, the midsole  230  curves away from the longitudinal plane at the toe end  242  and the heel end  246  and also within the midfoot region  110 . To that end, the midsole  230  is convexly curved in the forefoot region  108  and the heel region  112  and concavely curved in the midfoot region  110 . It is contemplated that the outsole  150  is concavely or convexly curved in other directions, such as between the lateral side  118  and the medial side  116  (see  FIG.  1   ). In addition, the upper surface  234  of the midsole  230  follows a different curvature than the lower surface  238 , such that the upper surface  234  is substantially more planar in the heel region than the lower surface  238 , although other configurations are possible. Further, the midsole  230  and the outsole  150  are configured to be mated or fit with one another, such that the top surface  154  of the outsole  150  is curved and shaped to be in contact with the lower surface  238  of the midsole  230 , as illustrated in  FIG.  4   . 
       FIG.  4   , schematic representation of the midsole  230  and the outsole  150  forming an interlocking assembly  286 , which comprises at least part of sole structure  104  (see  FIG.  1   ) for the article of footwear  100 . In the illustrated embodiment of  FIG.  4   , the outsole  150  is partially received within the midsole  230  and, in particular, the ribs  174 A-D of the outsole  150  are received within the receptacles  262 A-D of the midsole  230  to secure the outsole  150  to the midsole  230 . Further, the ribs  174 A-D are configured to be removably coupled to the midsole  230  within the receptacles  262 A-D, such that a user can selectively assemble and disassemble the interlocking assembly  286  by selectively coupling and decoupling the outsole  150  with the midsole  230 . In this way, an interlocking function is performed by the ribs  174 A-D of the outsole  150  interacting with the receptacles  262 A-D of the midsole  230 . 
     In  FIG.  4   , the ribs  174 A-D are illustrated as being fully interlocked, i.e., fully assembled, with the receptacles  262 A-D. To that end, an exemplary assembly process includes the head  178  of each rib  174  being received through the corresponding aperture  258  and within the corresponding receptacle  262 . In particular, the head  178  of each rib  174  is aligned with the corresponding aperture  258  of the midsole  230  and then pushed or pressed against the flanges  270  of the lower surface  238  of the midsole  230  to pass the head  178  through the aperture  258  and toward the receptacle  262 . Due to the enlarged size of the head  178  relative to the aperture  258 , the head  178  is deformed, e.g., compressed, as it passes through the aperture  258 . In some embodiments, the cavity  190  of each head  178  permits greater deformation, e.g., collapse, during assembly. Then, after the head  178  is pushed or pressed past the aperture  258  and into the receptacle  262 , the head  178  expands to contact the interior surface  266 , thereby at least partially filling the receptacle  262 , while the stem  186  and the base  182  of each rib  174  are at least partially disposed within and at least partially fill the aperture  258 . To that end, the head  178  of the rib  174  may expand so rapidly that an audible sound, e.g., a snap, click, or pop, is generated by contact with the interior surface  266  of the receptacle  262 . In this way, the rib  174  snaps within the receptacle  262  and, thus, the outsole  150  snaps into the midsole  230 . At the same time, the flanges  270  of the midsole  230  fit on either side of each rib  174  and are received within the gaps  198  of the outsole  150 . Accordingly, disassembly or removal of the head  178  form the receptacle is resisted by the narrowed configuration of the aperture  258  to prevent accidental or unintended disassembly. 
     In some embodiments, the flanges  270  are deformed and/or displaced during assembly due to contact with the ribs  174 . In some embodiments, the flanges  270  remain undeformed and in place while the ribs  174  become deformed or displaced due to contact with the flanges  270 . The outsole  150  is retained against and/or secured to the midsole  230  at least partially due to the enlarged size of the head  178  and receptacle  262  relative to the stem  186  and aperture  258 . In some embodiments, the ribs  174 A-D may be fit within the receptacles  262 A-D by a sliding translation in a lateral-to-medial or medial-to-lateral direction. 
     It is contemplated that the head  178  may be displaced, e.g., rotated or bent, about the stem  186  or base  182  of the rib  174  during the assembly process to further enhance retention of the outsole  150  to the midsole  230  after assembly. Additionally or alternatively, the head  178  may become displaced from a pre-assembly configuration (see  FIG.  2   ) to an assembled configuration (see  FIG.  4   ), such that the angle θ is increased or decreased through the assembly process. In addition, with reference to  FIG.  4   , the height H1 of the ribs  174  is less than the height H2 of the midsole  230 . In the illustrated embodiment, the ribs  174  of the outsole  150  are of a height H1 that is approximately 75% of the height H2 of the midsole  230 . In some embodiments, the ribs  174  of the outsole  150  are of a height H1 that is greater than 75% of the height H2 of the midsole  230  or, alternatively, the ribs  174  are disposed at varying heights H1 that are greater than or less than 75% of the height H2 of the midsole  230 . 
     As illustrated in  FIG.  4   , the toe end  162  of the outsole  150  is spaced apart from the toe end  242  of the midsole  230 , while the heel end  166  of the outsole  150  is aligned and coextensive with the heel end  246  of the midsole  230 . In some embodiments, the toe end  162  of the outsole  150  and the toe end  242  of the midsole  230  are aligned and coextensive. Further, the outsole  150  and the midsole  230  are fit together such that the top surface  154  of the outsole  150  is tightly or firmly pressed against the lower surface  238  of the midsole  230 . In some embodiments, voids or discontinuities (not shown) may be formed between the top surface  154  of the outsole  150  and the lower surface  238  of the midsole  230 . 
     It is contemplated that the outsole  150  and/or the midsole  230  can each be constructed as a single, unitary component or, alternatively, each can be constructed of multiple discrete or separable components. It is further contemplated that the outsole  150  and the midsole are manufactured separately from one another. In this way, more complex geometries, e.g., an undercut, can be achieved as compared to a process in which the outsole  150  and the midsole  230  are formed together and/or coupled by traditional means, such as cementing or co-molding. In addition, due to the separate manufacture of the outsole  150  and the midsole  230 , lower dimensional tolerances, i.e., accuracy, is required. Further, the outsole  150  can be detached from the midsole  230  without causing damage to the either the outsole  150  or the midsole  230 . In this way, the outsole  150  and the midsole  230  can be separated and/or assembled at various stages in the lifecycle of the footwear  100  and by various individuals, e.g., manufacturers and consumers, among others. Additionally, the outsole  150  can be removed and recycled separately from the footwear  100  or the midsole  230 . Further, the outsole  150  can be removed by the consumer for replacement with another outsole  150  having different performance properties, such as, e.g., stiffness or cushioning in different locations along the forefoot region  108 , midfoot region  110 , heel region  112 , lateral side  118 , and medial side  116 . 
     With reference to  FIG.  5   , another embodiment of an interlocking assembly  302  includes an outsole  306  and a midsole  310  that are illustrated in a partially assembled configuration. The midsole  310  and outsole  306  of  FIG.  5    are similar to the embodiments of  FIG.  4    and, thus, equivalent reference numerals will be used to indicate equivalent elements. As illustrated in  FIG.  5   , the outsole  306  includes ribs  314 , similar to the ribs  174  of  FIG.  2   . The ribs  314  are a plurality including ribs  314 A,  314 B,  314 C,  314 D,  314 E,  314 F, labeled in sequential order moving in a toe-to-heel direction, i.e., heel-ward. Accordingly, the rib  314 A is located farthest from the heel end  166  and the rib  314 F is located closest to the heel end  166 . Likewise, the midsole  310  includes apertures  318  and receptacles  322 , similar to those of the midsole  230  of  FIG.  3   . With respect to the midsole  310  in  FIG.  5   , the apertures are a plurality including apertures  318 A,  318 B,  318 C,  318 D,  318 E,  318 F, labeled in sequential order moving in a toe-to-heel direction, i.e., heel-ward. Further, the receptacles  322  are a plurality including receptacles  322 A,  322 B,  322 C,  322 D,  322 E,  322 F, labeled in sequential order moving in a toe-to-heel direction, i.e., heel-ward, and corresponding to the apertures  318 A,  318 B,  318 C,  318 D,  318 E,  318 F. For purposes of clarity, it will be appreciated that the ribs  314 A-F, the apertures  318 A-F, and the receptacles  322 A-F may be referred to herein individually or collectively as rib(s)  314 , aperture(s)  318 , and receptacle(s)  322 , respectively. 
     It will be appreciated from  FIGS.  5  and  6    that another method for assembling the outsole  306  to midsole  310  begins by aligning the heel end  166  of the outsole  306  with the heel end  246  of the midsole  310  and positioning the midsole  310  and the outsole  306  in a “V” shape with the heel ends  166 ,  246  brought together. Then, the rib  314 F, which is the most heel-ward, is aligned with the most heel-ward aperture  318 F and then pushed or pressed against the flanges  270  of the lower surface  238  of the midsole  310  to pass the head  178  through the aperture  318 F and toward the receptacle  322 F. In doing so, the midsole  310  may be flexed or bent, as illustrated in  FIG.  5   , to use a mechanical lever arm and elastic material properties of the midsole  310  for facilitating insertion of the rib  314 F within the receptacle  322 F. Further, once the rib  314 F is received within the receptacle  322 F, the remaining ribs  314  are aligned with their corresponding apertures  318  and receptacles  322 . Thus, the midsole  310  and the outsole  306  are brought together to cause the remaining ribs  314  to be received within corresponding apertures  318  and receptacles  322 . In particular, the adjacent rib  314 E is inserted within the receptacle  322 E, after which the rib  314 D is inserted within the receptacle  322 D, and so on consecutively and successively until the rib  314 A is inserted within the receptacle  322 A, as illustrated in  FIG.  6   . In this way, the ribs  314 A-F are received within and interlocked with the receptacles  322 A-F of the midsole  310  in a successive and consecutive interlocking progression moving in a heel-to-toe, i.e., toe-ward, direction. Finally, after the rib  314 A is inserted within the receptacle  322 A, the toe end  162  (see  FIG.  6   ) of the outsole  150  can be fit within a groove  326  (see  FIG.  5   ) provided on the lower surface  238  of the midsole  310 . 
       FIGS.  5  and  6    illustrate an embodiment of the outsole  306  in which the toe end  162  of the outsole  306  is located within the groove  326  in the midfoot region  110  of the article of footwear  100 . Further, as noted above, the outsole  306  generally remains stationary during the assembly process of  FIG.  5    while the midsole  310  is flexed, which may be a function of the different materials used to form the outsole  306  and the midsole  310 . To that end, the outsole  306  is generally formed of a material having a greater density and, thus, a higher stiffness or rigidity, than a material of the midsole  310 . In this way, the midsole  310  can also provide greater cushioning properties for a user while the outsole  306  can provide greater wear-resistance and stability properties. Further, because the outsole  306  can be decoupled from the midsole  310 , the outsole  306  can be cleaned, replaced, and recycled separately from the article of footwear  100 . 
     It is contemplated that the outsole  306  and the midsole  310  may be configured to provide varying levels of comfort and performance properties for a user of the article of footwear  100 . In some embodiments, the ribs  314  are configured to increase rigidity or stiffness in comparison to the midsole  310 . In some embodiments, the ribs  314  are configured to increase spring-like resistance forces in particular areas or locations of the sole structure  104  (see  FIG.  1   ) when compressed during use. In some embodiments, such as in  FIGS.  5  and  6   , the ribs  314  are configured to improve aesthetic features of the sole structure  104 . To that end, the ribs  314  may be exposed through the medial side  116  and the lateral side  118  of the midsole  310 , as illustrated in  FIG.  5   . Alternatively, the ribs  314  may be hidden or concealed from a side view, such as in the sole structure  104  of  FIG.  1   . 
       FIG.  7    illustrates another embodiment of an interlocking assembly  334  including an outsole  338  and a midsole  342  in an assembled configuration. In the illustrated embodiment, the outsole  338  includes ribs  346 , similar to the embodiments of  FIGS.  2  and  5   . In particular, the outsole  338  is illustrated with a plurality of ribs  346 . Further, the midsole  342  is illustrated from a top plan view with the plurality of ridges  250  located within the midfoot region  110  and the forefoot region  108  and with the rim  254  extending about the heel region  112  of the upper surface  234 . It is contemplated that the plurality of ridges  250  are configured to increase flexibility and reduce an overall weight of the midsole  342 . In addition, the head  178  of the rib  346 A is partially exposed through a hole  350  within the upper surface  234  of the midsole  342  as a result of a curvature at least partially formed by the rim  254  between the lateral side  118  and the medial side  116  of the midsole  342 . To that end, the hole  350  of the midsole  342  is configured to allow movement or transfer of air, which improves moisture control and breathability of the article of footwear  100 . 
     Referring to  FIG.  7   , the outsole  338  is configured to extend from the lateral side  118  of the midsole  342  and, in particular, the head  178  of each of the ribs  346  of the outsole  338  protrudes or extends from the lateral side  118  of the midsole  342 . In this way, the ribs  346  of the outsole  338  may be visible from a side view of the article of footwear  100  to impart particular performance properties and/or to create a visual impression. In some embodiments, the head  178  includes a peripheral flange  354  that extends outwardly as a thin section of material. In some embodiments, the ribs  346  may provide particular lateral or medial stability properties to support changes in direction, to prevent rolling or turning an ankle, or allow for greater traction control, among other desirable properties. Further, the visual impression of the article of footwear  100  may be customized to express creativity or information by way of the ribs  346  of the outsole  338 . For example, the head  178  of one or more of the ribs  346  may be shaped as an alphabetical or numerical symbol, such that a user’s name, a team name, a phrase, logo, brand, symbol, or even a jersey number may be displayed by the article of footwear  100 . In some examples, one or more of the ribs  346  may be provided in a particular shape or color that corresponds to a grade of stiffness, such as, e.g., a red color may indicate a greater stiffness and a blue color may indicate lower stiffness. Further, the ribs  346  may extend outwardly from the midsole  342  at varying distances relative to one another, as depicted in  FIG.  7   . 
       FIG.  8    illustrates another embodiment of an interlocking assembly  358  including an outsole  362  and a midsole  366  in an assembled configuration. In the illustrated embodiment, the outsole  362  includes a plurality of ribs  370  that are recessed, e.g., offset inwardly, within corresponding receptacles  374  from the medial side  116  of the midsole  366 . In particular, the interlocking assembly  358  is illustrated from a bottom perspective view, wherein the interior surface  266  of each receptacle  374  is visible as a result of the recessed position of the ribs  370  within the receptacles  374 . Further, the receptacles  374  are open and exposed on the medial side  116  of the midsole  366 . Similar to the embodiment of  FIG.  7   , the ribs  370  are exposed from the medial side  116  of the midsole  366  to impart particular performance properties and/or to create a visual impression, as described above. It is also contemplated the ribs  370  may be exposed from the lateral side  118 . 
     The interlocking assemblies  286 ,  302 ,  334 ,  358  are provided as a lock-and-key configuration in which a particular outsole is configured to fit with a particular midsole by way of particular arrangements or configurations of projections and/or ribs that removably interlock with voids and/or receptacles. To that end, it is contemplated that the interlocking assemblies  286 ,  302 ,  334 ,  358  may be formed with a reversal of parts, e.g., having projections or ribs extending from the midsole and voids or receptacles that are formed on the outsole, or some combination thereof. Additionally, the interlocking assemblies  286 ,  302 ,  334 ,  358  may be retained and/or secured with the use of additional fasteners, such as, e.g., magnetic elements, hook and loop fasteners, buckles, zippers, rail fasteners, or the like. 
     It is further contemplated that the interlocking assemblies  286 ,  302 ,  334 ,  358  afford additional features as compared to traditional sole structure assembles, such as, e.g., an ability to remove the outsole for continued indoor wear of the footwear indoors. For example, instead of a user removing the entire footwear, one may simply remove the outsole, which may be relatively dirty and/or contaminated by outdoor use, and continue to wear indoors the footwear with the cushioning properties of the relatively cleaner midsole, which is relatively less dirty and/or contaminated as compared to the removable outsole. Such indoor use of the footwear with the outsole removed may present benefits in a variety of applications, such as, e.g., more quickly entering and exiting a residential or commercial building by way of the simplified action of attaching or detaching the outsole. 
     Additionally, the interlocking assemblies  286 ,  302 ,  334 ,  358  may reduce the need for additional pairs or sets of footwear by expanding the versatility of the footwear to become suitable for a variety of applications. For example, a midsole and upper may be configured for use in several different activities, including running, walking, basketball, tennis, weight-lifting, golf, and soccer, among others, while the outsole is configured for use with only one or less than all of such activities. In some examples, the outsole can carry particular ground-engaging elements, such as cleats, spikes, or the like, that are suited for particular activities, while the midsole and upper are configured to be universal, i.e., suitable for activities beyond those particular outsoles. 
       FIG.  9    illustrates a schematic representation of a top plan view of another embodiment of an outsole  404  similar to the outsole  150 , such that the outsole  404  includes the top surface  154  that extends from the toe end  162  to the heel end  166 . In the illustrated embodiment of  FIG.  9   , the outsole  404  is depicted with the longitudinal plane L and the central plane C extending therethrough, for illustrative purposes. The outsole  404  includes a first attachment region  408  within the forefoot region  108 , a second attachment region  412  within the midfoot region  110 , and a third attachment region  416  within the heel region  112 . It is contemplated that greater or fewer attachment regions may be located in various locations on the outsole  404 . By comparison, the outsole  150  includes the outsole attachment region  194  within the heel region  112 , as illustrated in  FIG.  2   . Turning back to  FIG.  9   , the first attachment region  408  is illustratively depicted with an imaginary first boundary line  420 , the second attachment region  412  is illustratively depicted with an imaginary second boundary line  424 , and the third attachment region  416  is illustratively depicted with an imaginary third boundary line  428 . A first plurality of ribs  432  are located within the first boundary line  420  of the first attachment region  408 . It is contemplated that the first boundary line  420  extends along a periphery defined by the first plurality of ribs  432 , such that one or more of the ribs  432  are located on or coincident with the first boundary line  420 . In some embodiments, one or more of the ribs  432  are spaced apart from the first boundary line  420  within the first attachment region  408 . 
     In the illustrated embodiment of  FIG.  9   , the first plurality of ribs  432  are provided of varying sizes and shapes and of different configurations. In particular, the first plurality of ribs  432  includes rib  432 A in the form of a thin, linear projection extending continuously in a lateral-to-medial direction, i.e., parallel to the central plane C and spaced centrally on the outsole  404  between the lateral side  118  and the medial side  116 . The first boundary line  420  borders the rib  432 A at opposing ends thereof, such that the rib  432 A is coincident with and adjacent to the first boundary line  420 , although other configurations are possible. Further, the first plurality of ribs  432  includes ribs  432 B in the form of thin, linear projections extending continuously at angles relative to the central plane C and having opposing ends adjacent to and coincident with the first boundary line  420 . Further, the ribs  432 B are disposed such that a distance between them increases in a medial-to-lateral direction. Further, the first plurality of ribs  432  includes rib  432 C in the form of a rectangular projection extending continuously substantially parallel to the central plane C and having opposing ends that are adjacent to and coincident with the first boundary line  420 . The ribs  432 C is relatively thicker in a horizontal direction, i.e., parallel with the longitudinal plane L, than the ribs  432 A and  432 B. Further, the first plurality of ribs  432  includes rib  432 D in the form of a generally rectangular projection having cross-members spaced between opposing ends of the rib  432 D. The rib  432  is spaced from the first boundary line  420  and disposed at an angle relative to the central plane C. Thus, the first plurality of ribs  432  includes ribs of varying thickness relative to one another, ribs disposed at varying angles relative to one another, and ribs of different shapes and sizes. 
     In addition, the top surface  154  is depicted as including a texture, i.e., a localized deviation from a perfectly flat plane, within the first attachment region  408  and, thus, within the first boundary line  420 . In some embodiments, the top surface  154  may include a variety of texture characteristics, such as, e.g., roughness, waviness, and form, among others. The top surface  154  may be textured by a variety of methods, such as, e.g., grinding, cutting, lapping, blasting, sanding, honing, milling, reaming, laser treatment, additive manufacturing, among others. In any case, the top surface  154  may be textured to increase friction during engagement with an external surface, such as with a midsole. Further, the top surface  154  may include a layer, substrate, or sheet of a different material than the outsole  404  to provide similar frictional or engagement properties. 
     Still referring to  FIG.  9   , the second attachment region  412  includes a second plurality of ribs  436  of varying sizes and shapes and of different configurations. In particular, the second plurality of ribs  436  includes a set of ribs  436 A in the form of discrete, square-shaped protrusions arranged in a generally linear row, spaced apart from one another between the medial side  116  and the lateral side  118 . One or more of the ribs  436 A are coincident with and adjacent to the second boundary line  424 , and, further, one or more of the ribs  436 A are spaced apart from the second boundary line  424  within the second attachment region  412 . The set of ribs  436 A is arranged asymmetrically about the longitudinal plane L, such that the set of ribs  436 A is offset toward the medial side  116 , although other configurations are possible. In addition the second plurality of ribs  436  includes a set of ribs  436 B in the form of discrete, square-shaped projections that are located within the midfoot region  110  and intersected by the central plane C. As such, the set of ribs  436 B are located along the central plane C, coplanar with one another. Further, set of ribs  436 B are spaced apart from one another a greater distance than a distance with which the set of ribs  436 A are spaced from one another. That is, the set of ribs  436 B are arranged such that one of the ribs  436 B is located adjacent the medial side  116  and the other of the ribs  436 B is located adjacent the lateral side  118 . Further, the second plurality of ribs  436  includes ribs  436 C in the form an array of six discrete, square-shaped projections disposed linearly between the lateral side  118  and the medial side  116 . The ribs  436 C are located a spaced a uniform distance apart from one another and the array of ribs  436 C is generally symmetrical about the longitudinal plane L. In addition, the ribs  436 C are generally smaller square-shape projections than the ribs  436 A and  436 B. Thus, the second plurality of ribs  436  includes ribs of varying arrangements and spacings from another, ribs arranged in asymmetrical and symmetrical relationships, ribs that are provided as discrete sets or arrays of projections, and ribs of different shapes and sizes and quantities. 
     With continued reference to  FIG.  9   , the third attachment region  416  includes a third plurality of ribs  440  of varying sizes and shapes and of different configurations. In particular, the third plurality of ribs  440  includes a set of ribs  440 A in the form of discrete, generally elliptical or circular projections of varying sizes and shapes relative to one another. In addition, the set of ribs  440 A are arranged to be asymmetrical about the longitudinal plane L and the ribs  440 A are spaced varying distances from one another. Moreover, at least one of the ribs  440 A is located farther outwardly from the longitudinal plane L than the lateral side  118 , although it is contemplated that at least one of the ribs  440 A may also be located farther outwardly from the longitudinal plane L than the medial side  116 . At least one of the ribs  440 A is intersection by the longitudinal plane L, although other configurations are possible. In addition, the third plurality of ribs  440  includes a set of ribs  440 B in the form of discrete, generally elliptical or circular projections arranged along a curved path  444  between the lateral side  118  and the medial side  116 . The curved path  444  is depicted as being a convex curvature relative to the central plane L, although other configurations are possible. Further, the third plurality of ribs  440  includes the ribs  440 C in the form of discrete, generally elliptical or circular projections of substantially different sizes. In particular, a largest of the ribs  440 C may be greater than double the size of a smallest of the rib  440 C. Thus, the second plurality of ribs  436  includes ribs of varying arrangements and spacings from another, ribs arranged in non-linear or curved paths, ribs that are located outwardly of the lateral and/or medial sides, and ribs of substantially different shapes and sizes and quantities. In the illustrated embodiment, the third attachment region  416  extends outwardly from the lateral side  118 . Further, the top surface  154  is depicted as being generally smooth within the third attachment region  416 . 
       FIG.  10    illustrates a schematic representation of a side view of a portion of another embodiment of an outsole  500 . In particular, the outsole  500  includes a modified rib  504  that has a head  508  in the form of a generally elliptical, solid, member that is connected to a stem  512 . The stem  512  defines the projection axis P and is disposed at an angle θ, which is less than 90 degrees, although other configurations are possible. An end of the head  508  is connected to the stem  512 , such that the head  508  is offset from the projection axis P. In addition, the outsole  500  includes another modified rib  516  having a head  520  connected to a stem  524 . In particular, the head  520  is shaped to represent a number, i.e., twenty-two (22). It is contemplated that the head  520  may be shaped to represent a different number, or an alphabetical symbol, or a variety of other symbols or shapes. Further, the stem  524  is depicted as comprising three parallel columnar members spaced apart from one another and disposed substantially orthogonally relative to the longitudinal plane L. In this way, the stem  524  includes gaps or voids thereon. It is contemplated that the stem  524  provides particular cushioning and/or stiffness performance properties that may differ from, for example, the stem  512 . For instance, the stem  524  may provide an initial deformation resistance, e.g., upon impact caused by a user bearing weight generally vertically downward, before deforming and/or buckling as a result of the impact, after which the three columnar members of the stem  524  may contact one another to again impart deformation resistance, e.g., a spring-like reaction. Said another way, the stem  524  may be configured to act as a non-linear or linear dampening spring in which resistance varies as a function of time measured after impact. Moreover, the outsole  500  includes yet another modified rib  528  that has a head  532  connected to a stem  536 . In particular, the head  532  is positioned between opposing ends of the stem  536 , e.g., approximately half of a height of the stem  536 , rather than at an end of the stem  536  opposite the top surface  154  of the outsole  500 . Further, the head  532  is provided in the form of a protuberance extending generally parallel to the longitudinal plane L and having a cross-sectional shape resembling a right triangle, although other configurations are possible. For example, the head  532  may be disposed radially about a portion of the stem  536 . In addition, the head  532  is arranged such that the angled side of the right triangle is positioned farther from the top surface  154  of the outsole  500  than the straight side of the right triangle. In this way, the head  532  is configured for ease of installation within a receptacle of a midsole, as well as for greater retention within the receptacle to resist disassembly or detachment from the midsole. 
       FIG.  11    illustrates a schematic representation of a perspective view of another embodiment of an outsole  600 . In the illustrated embodiment, the outsole  600  includes a top side  604  that is opposite a bottom side or ground-facing surface  608  and a clip  612  extending from the top side  604  at the heel end  124  of the outsole  600 . Further, the outsole  600  includes ribs  616  extending from the top side  604  and spaced apart from one another in a heel-to-toe direction, the plurality of ribs  616  comprising a rear set  620  and a front set  624 . The rear set  620  of ribs  616  spans from the heel region  112  to the midfoot region  110  of the outsole  600 , the front set  624  of ribs  616  spans from the midfoot region  110  to the forefoot region  108  of the outsole  600 , and an arch cavity  628  is positioned between the front set  624  and the rear set  620 . In addition, the ribs  616  extend continuously from the lateral side  118  to the medial side  116  of the outsole  600 . The ribs  616  within the front set  624  are a plurality including ribs  616 A,  616 B,  616 C,  616 D,  616 E,  616 F,  616 G, labeled in sequential order moving in a toe-to-heel direction, i.e., heel-ward. Further, the ribs  616  within the rear set  620  are a plurality including ribs  616 H,  616 I,  616 J,  616 K,  616 L,  616 M, labeled in sequential order moving in the heel-ward direction. Accordingly, the rib  616 A is located farthest from the heel end  124  and the rib  616 M is located closest to the heel end  124 . In addition, the rib  616 M is coupled to the clip  612  extending from the heel end  124 , and a chamber  632  is formed between the rib  616 M and the clip  612  in fluid communication with a pair of through holes  636  and  640  formed in the clip  612  on medial and lateral sides,  116 ,  118 , respectively. In the embodiment illustrated, the clip  612  is T-shaped and includes a pair of wings  644  and 648 that each curve from the heel end  124  to the respective medial side  116  and the lateral side  118  of the outsole  600  to connect with the rib  616 M. 
     Still referring to  FIG.  11   , and with particular reference to the ribs  616 A and  616 B, each of the ribs  616  include a generally rounded or curved head  652  that is connected to a relatively thinner base  656 . For purposes of clarity, the head  652  and the base  656  are only labeled on the ribs  616 A,  616 B, but it will be understood that every rib  616  includes the head  652  and the base  656 . However, the ribs  616  are each uniquely configured to correspond, in part, to a particular location on the outsole  600 . For example, the ribs  616 A and  616 B, which are positioned within the front set  624  and adjacent the toe end  122  of the outsole  600 , are provided as substantially solid members that are comparatively thinner than the rest of the ribs  616 C-M. By contrast, the ribs  616 C-M are each substantially hollow, tubular members. Further, the ribs  616 A-M become increasingly thicker in sequential order moving in the heel-ward direction, with the exception of ribs  616 L and  616 M. To that end, the rib  616 A is the thinnest of the ribs  616  and the rib  616 K is the thickest of the ribs  616 , with each of the ribs  616 B-K having a comparatively greater thickness than the rib  616  positioned immediately toe-ward. Because the thickness of the rib  616  corresponds at least partially to the amount of pressure and support experienced, as well as to an amount of return energy and comfort offered by the rib  616 , it will be appreciated that the arrangement of thicknesses of the ribs  616  of the outsole  600  is provided for improved performance and comfort when worn by a user during various activities, such as, e.g., training, walking, and running, among others. However, it will be appreciated that ribs  616  having a different arrangement of thicknesses are within the scope of this disclosure. 
     Referring to  FIGS.  11  and  12   , the rib  616   g  is hollow and includes a cavity  660  extending from the medial side  116  to the lateral side  118  of the outsole  600 . Further, the cavity  660  communicates with a slot  664  that extends through the base  656 , such that the base  656  comprises a front leg  668  and a rear leg  672  spaced apart from one another across the slot  664  and connected to the head  652 . Accordingly, the front leg  668  and the rear leg  672  of the base  656  at least partially define the slot  664  and the head  652  at least partially defines the cavity  660  of the rib  616 G. For purposes of clarity, the cavity  660 , the slot  664 , the front leg  668 , and the rear leg  672  are only labeled with respect to the rib  616 G, but it will be appreciated that each of the ribs  616 C-M is hollow and includes cavity  660  extending from the lateral side  118  to the medial side  116 . Further, it will be appreciated that each cavity  660  of the ribs  616 C-L communicates with a slot  664  that extends through the base  656 . As illustrated in  FIG.  11   , the head  652  is generally rounded and, thus, the cavity  660  is also generally rounded like the head  652 ; likewise, the front and rear legs  668 ,  672  of the base  656  define the slot  664  with a varying thickness moving in a direction away from the head  652 , i.e., toward the top side  604  of the outsole  600 , starting to narrow gradually before widening at the top side  604 . Further, the slot  664  of each of the ribs  616 C-G of the front set  624  is open to and extends entirely through the outsole  600 , such that the slot  664  of each of the ribs  616 C-G extends through the bottom side  608  of the outsole  600 . Still further, the slot  664  of each of the ribs  616 H-L of the rear set  620  extends entirely through the outsole  600 , including the bottom side  608 , on the medial side  116  of the outsole  600  and spanning substantially between the medial side  116  and the lateral side  118  of the outsole  600 . However, the slot  664  of each of the ribs  616 H-L is interrupted by a traction strip  676  that curves along the bottom side  608  of the outsole  600  from the heel end  124  to the midfoot region  110  along the heel region  112  and on the lateral side  118  of the outsole  600 . Accordingly, the traction strip  676  spans across a lateral-heel portion of the slot  664  of each of the ribs  616 H-L. Additionally, a plurality of traction pads  680  are arranged on the bottom side  608  of the outsole  600  along the medial side  116  from the heel region  112  to the forefoot region  108 , as well as along the lateral side  118  within the forefoot region  108 . 
     Still referring to  FIGS.  11  and  12   , the ribs  616  are spaced apart from one another to form gaps  684  between the ribs  616  and across the top side  604  of the outsole  600 . The gaps  684  are sized and shaped in accordance with the ribs  616 , such that the gaps  684  are defined by the size or shape of the ribs  616  and by the spacing, i.e., distance, between each of the ribs  616 . The ribs  616  are spaced apart varying distances, such as the relatively larger distance between the rib  616 F and the rib  616 G. In the embodiment illustrated, a toe flap  688  narrows, i.e., measured in a lateral-to-medial direction, as it extends toe-ward of the frontmost rib  616 A. Additionally, the illustrated embodiment includes notches  692  provided in the form of curvilinear, oval-shaped depressions formed between adjacent ribs  616  and along the lateral side  118  and medial side  116  of the outsole  600 . 
       FIGS.  13  and  14    illustrate perspective, schematic representations of another embodiment of a midsole  696 . The midsole  696  includes a top surface  700  that is opposite a bottom surface  704 , a rim  708  extending along a periphery  712  of the top surface  700 , and a plurality of apertures  716  extending through the bottom surface  704  toward the top surface  700 . Additionally, each of the apertures  716  is connected to a receptacle  720  that is configured to receive one of the ribs  616  of the outsole  600  to form an interlocking assembly  724 , as illustrated in  FIG.  15   . Referring back to  FIGS.  13  and  14   , the apertures  716  of the midsole  696  include apertures  716 A-M, which are labeled in sequential order moving in the heel-ward direction, and the receptacles  720 A-M, which are also labeled in sequential order moving in the heel-ward direction and corresponding to the apertures  716 A-M. Further, the apertures  716 A-G and receptacles  720 A-G comprise a front group  728  of the midsole  696  that spans within the forefoot region  108 . Similarly, the apertures  716 H-M and receptacles  720 H-M comprise a rear group  732  of the midsole  696  that spans within the heel region  112 . An arch support  736  is positioned within the midfoot region  110  of the midsole  696  and separates the front group  728  from the rear group  732 . It will also be appreciated that the midsole  696  includes a plurality of flanges  740 A-M that at least partially define and bound the apertures  716 A-M and receptacles  720 A-M. For example, the flanges  740 A and  740 B bound and define the aperture  716 A and receptacle  720 A, the flanges  740 B and  740 C bound and define the aperture  716 B and receptacle  720 B, and so on. Further, the arch support  736  opposes the flange  740 G to bound and define the aperture  716 G and receptacle  720 G in the front group  728  of the midsole  696 , and the arch support  736  also opposes the flange  740 H to bound and define the aperture  716 H and receptacle  720 H of the rear group  732  of the midsole  696 . In general, each of the flanges  740  and the arch support  736  are thicker near the bottom surface  704  and curve inwardly to become thinner moving in a direction toward the top surface  700  of the midsole  696 . 
     As illustrated in  FIGS.  13  and  14   , the receptacles  720  and the apertures  716  are provided of varying sizes and shapes. For example, the receptacle  720 A and aperture  716 A are relatively thinner, i.e., measured in a heel-to-toe direction that is parallel to the longitudinal axis L, and narrower, i.e., measured in a lateral-to-medial direction, than the adjacent aperture  716 B and receptacle  720 B. Further, the aperture  716 B and receptacle  720 B are thinner and narrower than adjacent aperture  716 C and receptacle  720 C. Accordingly, the flanges  740 A-M are also provided of varying sizes and shapes, particularly of varying thicknesses and widths. Further, the arch support  736  is relatively thicker than each of the flanges  740 A-M and generally T-shaped, as best viewed in  FIG.  14   . Referring to  FIG.  13   , the rearmost flange  740 M is provided with a securing feature in the form of first and second blocks  744  and  748  at the heel end  124  of the midsole  696 . The first block  744  is located on the medial side  116  of the midsole  696  and the second block  748  is located on the lateral side  118  of the midsole  696 . Accordingly, the blocks  744 ,  748  are spaced apart from one another and separated by the longitudinal axis L. Further, the blocks  744 ,  748  are disposed closer to the bottom surface  704  of the midsole  696  than to the top surface  700 . In the illustrated embodiment, the blocks  744 ,  748  are generally ellipsoidal-shaped projections that extend outwardly from the heel end  124  of the midsole  696 . In particular, the first block  744  extends outwardly from the medial side  116  of the flange  740 M and the second block  748  extends outwardly from the lateral side  118  of the flange  740 M, although other configurations are possible. Additionally, a plurality of nubs  752  in the form of curvilinear, oval-shaped projections are disposed along the lateral side  118  and the medial side  116  of the flanges  740  and extend from the bottom surface  704  of the midsole  696 . In the illustrated embodiment, the nubs  752  are spaced apart from one another and span across the heel region  112 , the midfoot region  110 , and the forefoot region  108 . For purposes of clarity, only the nubs  752  along the lateral side  118  are labeled in  FIG.  14   . 
     Referring to  FIGS.  15  and  16   , the outsole  600  and the midsole  696  together comprise the interlocking assembly  724  that is configured to be removably attached and detached as part of the sole  104  for an article of footwear. For purposes of clarity, the ribs  616  of the outsole  600  are referenced as the front set  624  and the rear set  620 ; similarly, the apertures  716 , the receptacles  720 , and the flanges  740  of the midsole  696  are referenced as the front group  728  and the rear group  732 . Accordingly,  FIG.  15    illustrates the interlocking assembly  724  in an assembled configuration in which the front set  624  of ribs  616  are configured to be removably coupled with the front group  728  of receptacles  720 , the rear set  620  of ribs  616  are configured to be removably coupled with the rear group  732  of receptacles  720 , and the arch support  736  is configured to fit within the arch cavity  628 . In some embodiments, the outsole  600  and the midsole  696  are flexed to be removably coupled together in a manner similar to the one described in connection with  FIG.  5   , although other configurations are possible. In some embodiments, only one of the outsole  600  and the midsole  696  is flexed during assembly to form the interlocking assembly  724 . It is further contemplated that the interlocking assembly  724  may be assembled by pressing the outsole  600  and the midsole  696  against one another in a substantially vertical direction, i.e., perpendicular to a longitudinal direction defined by the longitudinal axis L, such that no flexing occurs. 
     Further, as depicted in  FIG.  16   , the clip  612  of the outsole  600  is configured to fit onto the rearmost flange  740   m  at the heel end  124  of the midsole  696  and the blocks  744 ,  748  are configured to extend through the respective through holes  636 ,  640  formed in the clip  612  of the outsole  600 . As such, the flange  740 M is received within the chamber  632  and the blocks  744 ,  748  are received in the respective through holes  636 ,  640  of the clip  612  to assist with locating and/or aligning the outsole  600  and the midsole  696  to form the interlocking assembly  724 . Further, the flange  740 M fits tightly inside the chamber  632  between the rib  616 M and the clip  612 , while the blocks  744 ,  748  fit tightly inside the through holes  636 ,  640 , respectively. As a result, the blocks  744 ,  748  and clip  612 , via the through holes  636 ,  640 , secure the heel end  124  of the interlocking assembly  724  to prevent displacement during use, i.e., activities involving rapid acceleration, high impact forces, continuous and repeated compression and expansion, change in directions or speed, exposure to outdoor environments, any combination thereof, and the like. In addition, when the interlocking assembly  724  is assembled, the notches  692  of the outsole  600  are configured to receive the nubs  752  of the midsole  696  to further assist with alignment and to secure the outsole  600  against displacement relative to the midsole  696 . 
     Referring back to  FIGS.  11 - 15   , when the outsole  600  and the midsole  696  are provided in the assembled configuration, the flanges  740  of the midsole  696  are received in the corresponding gaps  684  of the outsole  600 , the ribs  616  of the outsole  600  are received through the corresponding apertures  716  and within the corresponding receptacles  720  of the midsole  696 , and the arch support  736  is received within the arch cavity  628  of the outsole  600 . Further, in the assembled configuration, the interlocking assembly  724  may be coupled using additional and/or alternative fasteners, such as, e.g., hook-and-loop fasteners, magnetic elements, threaded fasteners, twist-lock fasteners, and any other suitable fastener that allows for removable attachment of the outsole  600  to the midsole  696  while preventing displacement in one or more directions, e.g., a toe-ward or heel-ward direction, a lateral and/or medial direction, and upward and/or downward directions. For example, it is contemplated that the toe flap  688  of the outsole  600  and the frontmost flange  740 A of the midsole  696  are removably secured together using hook-and-loop fasteners (not shown). In addition, it is contemplated that some or all of the front set  624  of ribs  616  and the front group  728  of receptacles  720  and apertures  716  can be replaced with alternative fasteners, such as hook-and-loop fasteners, among other configurations. 
     It is further contemplated the upper  102  may be removably attached to the sole  104  utilizing any of the interlocking assemblies  286 ,  302 ,  334 ,  358 ,  724  disclosed herein. For example, the upper  102  may comprise an insole (not shown) that is provided with a plurality of apertures and receptacles into which a plurality of ribs are configured to be received when assembled together, as a modified version of the interlocking assemblies  286 ,  302 ,  334 ,  358 ,  724 . Alternatively, the insole (not shown) of the upper  102  may be provided with a plurality of ribs that are configured to be received within apertures  716  and receptacles  720  of the sole  104 , such as in an inverted configuration of the interlocking assemblies  286 ,  302 ,  334 ,  358 ,  724 . Accordingly, the insole (not shown) may be provided as part of the upper  102  and/or permanently attached to the upper  102 , while the upper  102  is removably attached to the sole  104 . 
     Any of the embodiments described herein may be modified to include any of the structures or methodologies disclosed in connection with different embodiments. Further, the present disclosure is not limited to articles of footwear of the type specifically shown. Still further, aspects, such as the interlocking assembly, of the articles of footwear of any of the embodiments disclosed herein may be modified to work with any type of footwear, apparel, or other athletic equipment. 
     As noted previously, it will be appreciated by those skilled in the art that while the invention has been described above in connection with particular embodiments and examples, the invention is not necessarily so limited, and that numerous other embodiments, examples, uses, modifications and departures from the embodiments, examples and uses are intended to be encompassed by the claims attached hereto. The entire disclosure of each patent and publication cited herein is incorporated by reference, as if each such patent or publication were individually incorporated by reference herein. Various features and advantages of the invention are set forth in the following claims. 
     INDUSTRIAL APPLICABILITY 
     Numerous modifications to the present invention will be apparent to those skilled in the art in view of the foregoing description. Accordingly, this description is to be construed as illustrative only and is presented for the purpose of enabling those skilled in the art to make and use the invention. The exclusive rights to all modifications which come within the scope of the appended claims are reserved.