Patent Publication Number: US-2022225728-A1

Title: Rotatable midsole ambulatory footwear apparatus

Description:
FIELD 
     The present disclosure is related to rotatable midsole ambulatory footwear devices, systems, and methods, and particularly to foot rotation allowance about two axes and foot rotation restriction about a third axis. The devices. systems, and methods described herein relate to footwear that is adaptive to a ground surface orientation and/or rotational movements of the wearer&#39;s body, with considerations for comfort and wellbeing of the wearer. 
     BACKGROUND 
     Shoe soles are generally made of resilient materials to provide comfort for a user traversing modern hard and flat ground surfaces, e.g., concrete, asphalt, wood, tile, or the like. Soles may be manufactured by adding up to three or more, layers to a shoe last in the form of a human foot. The three layers may include an insole for interfacing with a user&#39;s foot, a midsole having structure and comfort features for supporting, the midsole, and an outsole for interfacing with a ground surface. Midsole layers often have a stiffening rigid shank for stability and for extending the life of the soles. Manmade hard ground surface terrains have produced the development of foam and other force absorbing midsole layers, such as cushioning sneakers. 
     However, these soles are not adapted to the natural walking or, running pattern of a foot engaging the ground. That is, they do not guide the foot along a natural walking or running path. If footwear soles were to better accommodate the natural moving pattern of a foot engaging the ground, user comfort and ambulatory efficiency could be improved. 
     During walking and running, the human foot typically contacts the ground at the outer portion of the heel. As the step advances, a greater portion of the heel, along with the outer portion of the arch of the foot, then contacts the ground. Next, the, inner portion of the ball of the foot contacts the ground. Following the contact by the inner ball of the foot, the remainder of the ball of the foot and the toes contact the ground. At this point, the foot is generally flat on the ground. As the heel begins to leave the ground, weight is transferred to the ball of the foot. After the heel and arch leave the ground, most of a person&#39;s weight is concentrated on the inner portion of the ball of the foot. As the foot begins to leave the ground, the inner portion of the ball of the foot and the big toe are the last areas to be in contact with the ground. This natural pattern of contact between the foot and the ground can generally be called an S-shape path. As a step advances, the point of contact is, in order, at the following locations: the heel, the outer arch, the inner ball, and the outer ball. This pattern is described in U.S. Pat. No. 7,610,695, which is hereby incorporated by reference herein for all purposes. 
     More than one hundred moving bones and joints in each foot transition in shape and position throughout each step and motion of the body. These step motions across variable terrain and shifting support for the movement of the rest of the user&#39;s body constantly struggle with, reassembling alignment of feet with the legs. For example, when traversing perpendicularly across a sloped hill, a user&#39;s downhill, foot must transition inwardly (e.g., y-axis inversion pronation), while the uphill foot must transition outwardly (e.g., y-axis eversion/supination), and both feet must progress in a forward direction (e.g., x-axis plantar flexion and dorsi flexion) to reassemble foot and leg alignment for body stability and mobility. 
     The described traditional footwear disrupts the natural transition sequence because the foot is restricted from transitioning within the footwear and often is forced into unfavorable rotation about a third axis (e.g., z-axis, as described herein) shearing from the internal and external ankle, and leg rotation with the foot. This rotation about a third axis may be described as, similar to the motion of extinguishing a cigarette on the ground with the plantar foot. The plantar foot is prematurely dismantled and forced into a shearing motion about the third axis inside the shoe, compromising alignment and functional health of the foot, ankle, leg, and hip. The plantar foot surface transitions shape within the shoe and does not maintain the single shape of the shoe last for which the shoe may be designed from. For example, a rigid mold of an orthosis will disrupt the foot&#39;s ability to transition, like a cast for a broken arm may restrict motion. A rigid sole or shank of a shoe disrupts the foot&#39;s ability to transition shape and position within the shoe and amplifies shearing. Excessive cushioning, gel, and foams of typical footwear may cause instability that may disrupt the foot&#39;s ability to transition and may amplify shearing by providing a soft and instable support structure for the foot to press against for performing step and foundational functions. 
     SUMMARY 
     This disclosure describes footwear embodiments that allow for natural foot rotational movement while preventing undesirable foot rotational movement by incorporating a freely movable sole that may shift within the footwear. 
     In various embodiments of the present disclosure, a footwear apparatus may include a primary outsole that may have a primary cavity. As used herein, “cavity” refers to any structure having a concave surface. A secondary outsole may be connected to the primary outsole. The secondary outsole may have a secondary cavity. A midsole may be movably disposed over the primary and secondary outsoles. The midsole may include a primary protrusion extending at least partially within the primary cavity. A tertiary outsole may be disposed about the primary protrusion. The footwear apparatus may define a z-axis through the secondary cavity and substantially normal to a ground surface. The apparatus may define a y-axis extending substantially from the secondary cavity to the primary cavity. An x-axis may be defined substantially normal to a plane created by the z-axis and the y-axis. The midsole may be configured to rotate substantially about the x-axis. The midsole may be configured to rotate substantially about the y-axis. The midsole may be configured to resist rotation substantially about the z-axis. A secondary protrusion may extend from the midsole and may extend at least partially into the secondary cavity. The primary protrusion may have a first radius that is smaller than a second radius of the primary cavity. The secondary protrusion may have a third radius that is smaller than a fourth radius of the secondary cavity. One or more outsole ribs or like members may be disposed on a top portion of the secondary outsole and may extend radially outward from the secondary cavity. One or more midsole ribs or like members may be disposed on a bottom portion of the midsole. The midsole ribs may extend radially outward from the secondary protrusion. The midsole ribs may be disposed adjacent to the one or more outsole ribs. One or more outsole ribs or like members may be disposed on a top portion of the primary outsole and may extend radially outward from the primary cavity. One or more midsole ribs or like member may be disposed on a bottom portion of the midsole. The midsole ribs may extend radially outward from the primary protrusion. The midsole ribs may be disposed adjacent to the one or more outsole ribs. An elongate body may extend from the primary outsole to the secondary outsole. The primary outsole may be continuous with the elongate body. The elongate body may be continuous with the secondary outsole. A pair of outsole arms may extend from the primary outsole and may extend about the primary cavity. A pair of midsole arms may be disposed on a bottom portion of the midsole and may extend about the primary protrusion and substantially opposing the outsole arms. A material layer may be disposed between the primary protrusion and the primary cavity. A plurality of air pockets may be in the material layer. Each air pocket may be located substantially adjacent to a tuberosity of a fifth metatarsal, a fifth metatarsal head, and/or a first metatarsal head of a user&#39;s foot disposed on the midsole. The primary protrusion and the tertiary outsole may be positioned to avoid a fifth metatarsal of a user&#39;s foot disposed on the midsole. The midsole may be a portion of a high heel shoe, a boot, a prosthetic leg, a rehabilitation walking boot, a flat shoe, a robotic limb, an athletic shoe, a sporting cleat, a skate, a sneaker, or any other suitable footwear. A secondary outsole extension may be disposed on the secondary outsole and may extend substantially away from the primary outsole. Each of the primary outsole, the secondary outsole, and the tertiary outsole may contact a ground surface. 
     In another aspect, a footwear apparatus may include a posterior outsole portion. A cavity may be located in the posterior outsole portion. A midsole portion may be disposed on a top portion of the posterior outsole portion. The midsole portion may extend away from the posterior outsole portion. An anterior outsole portion may extend from a portion of the midsole portion. An elongate body may extend from the anterior outsole portion toward the posterior outsole portion. A protrusion may be disposed at an end of the elongate body. The protrusion may extend at, least partially within the cavity. The footwear apparatus may define a z-axis through the cavity and may be substantially normal to a ground surface. A y-axis may extend substantially from the cavity through the elongate body. An x-axis may be substantially normal to a plane created by the z-axis and the y-axis. Each of the elongate body and the midsole portion may be configured to rotate about the x-axis. Each of the elongate body and the midsole portion may be configured to rotate about the y-axis. Each of the elongate body and the midsole portion may be configured to resist rotation about the z-axis. The protrusion may be a pin or a like member that is freely rotatable about the y-axis within the cavity. The pin may be reversibly engageable within the cavity about the x-axis. A pair of arms may extend from the elongate body about the anterior outsole portion. 
     In another aspect, a footwear apparatus may include a primary outsole comprising a first and a second primary arm. A secondary outsole may be connected to the primary outsole and may extend substantially away from the primary outsole. The secondary outsole may include a third and a fourth secondary arm. A midsole may be disposed over and may be connected to the primary outsole and the secondary outsole at a point. The footwear apparatus may define a z-axis through the point and may be substantially normal to a ground surface. A y-axis may extend substantially along the midsole, the primary outsole, and the secondary outsole. An x-axis may be substantially normal to a plane created by the z-axis and the y-axis. The midsole may be configured to rotate about the x-axis and the y-axis and may resist rotation about the z-axis. One or more outsole ribs may be disposed on the secondary outsole and may extend radially outward from about the point. One or more midsole ribs may be disposed on a bottom portion of the midsole. The midsole ribs may extend radially outward from the point. The midsole ribs may be disposed adjacent to the one or more outsole ribs. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a foot with a three-dimensional coordinate system. 
         FIGS. 2A-2E  illustrate a footwear device with a rotatable midsole, in accordance with an embodiment of the present disclosure. 
         FIGS. 3A and 3B  illustrate cross sections of a footwear device across a y-axis at a secondary cavity and at a primary cavity respectively with a rotatable midsole, in accordance with an embodiment of the present disclosure. 
         FIGS. 4A and 4B  illustrate a footwear device with a rotatable midsole, in accordance with an embodiment of the present disclosure. 
         FIG. 5  illustrates a footwear device with a rotatable midsole, in accordance with an embodiment of the present disclosure. 
         FIG. 6  illustrates a footwear device with a rotatable midsole, in accordance with an embodiment of the present disclosure. 
         FIG. 7  illustrates a footwear device with a rotatable midsole, in accordance with an embodiment of the present disclosure. 
         FIG. 8  illustrates a footwear device with a rotatable midsole, in accordance with an embodiment of the present disclosure. 
         FIG. 9  illustrates a footwear device with a rotatable midsole, in accordance with an embodiment of the present disclosure. 
         FIG. 10  illustrates a footwear device with a rotatable midsole, in accordance with an embodiment of the present disclosure. 
         FIG. 11  illustrates a footwear device with a rotatable midsole, in accordance with an embodiment of the present disclosure. 
         FIG. 12  illustrates a footwear device with a rotatable midsole, in accordance with an embodiment of the present disclosure. 
         FIGS. 13A and 13B  illustrate a footwear device with a rotatable midsole having anterior and posterior outsole arms, in accordance with an embodiment of the present disclosure. 
         FIG. 14  illustrates a footwear device with a rotatable midsole, in accordance with an embodiment of the present disclosure. 
         FIG. 15  illustrates a footwear device with a rotatable midsole, in accordance with an embodiment of the present disclosure. 
         FIG. 16  illustrates a footwear device with a rotatable midsole, in accordance with an embodiment of the present disclosure. 
         FIGS. 17A-17D  illustrate a footwear device with a rotatable midsole, in accordance with an embodiment of the present disclosure. 
         FIG. 18  illustrates a side cross-sectional view of a footwear device with a rotatable midsole, in accordance with an embodiment of the present disclosure. 
         FIGS. 19A-19B  illustrate a side cross-sectional view of a footwear device with a rotatable midsole, in accordance with an embodiment of the present disclosure. 
         FIG. 20  illustrates a side cross-sectional view of a footwear device with a rotatable midsole, in accordance with an embodiment of the present disclosure. 
         FIGS. 21A-21C  illustrate a side cross-sectional view of a footwear device with a rotatable midsole, in accordance with an embodiment of the present disclosure. 
         FIGS. 22-23  illustrate a method of manufacturing a footwear apparatus, in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Footwear is generally designed for protection, traction, and for movement between the footwear and a ground surface as a wearer takes a step. However, such footwear may restrict the foot to the mold of the shoe and/or the sole(s), and may allow for little to no movement of a midsole with respect to the outsole. A footwear device allowing midsole movement with respect to the outsole may assist a wearer&#39;s comfort, step efficiency, and lower-limb alignment health. 
     The inventor has found that allowing foot and/or midsole rotation within footwear about an axis in a plane that is generally parallel with the foot and/or ground surface is desirable, while rotation about an axis that is generally perpendicular to that plane is undesirable. Such undesirable rotation may be created, e.g., when a foot is traversing uneven terrain or when the body above the foot is rotating while keeping the foot fixed to the ground (e.g., turning, the upper body to face and/or reach for something in a direction other than forward while leaving the feet fixed on the ground pointing in the forward direction). Such rotation may create undesirable shearing, forces within the foot. 
     This disclosure focuses on a handful of discrete embodiments, with the intention of illustrating the principles of the systems and methods described. These descriptions are intended to be illustrative rather than limiting. Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosure belongs. 
     As used herein, the term “insole” refers to a sole or a portion of a sole that interfaces with a foot. The term “midsole” refers to a sole or a portion of a sole having structure for supporting the insole and/or interfacing with an outsole. The term “outsole” refers to a sole or a portion of a sole that interfaces with, a ground surface. Portions of any one of these types of soles may function as another type of sole. For example, a midsole may have a surface that is an insole that interfaces with a foot, while also having a portion that is an outsole that in certain positions interfaces with a ground surface. 
     As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises” and/or “comprising,” or “includes” and/or “including” when used herein, specify the presence of stated features, regions, steps elements and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components and/or groups thereof. As used herein, the conjunction “and” includes each of the structures, components, features, or the like, which are so conjoined, unless the context clearly indicates otherwise, and the conjunction “or” includes one or the others of the structures, components, features, or the like, which are so conjoined, singly and in any combination and number, unless the context clearly indicates otherwise. The term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise. 
     All numeric values are herein assumed to be modified by the term “about,” whether or not explicitly indicated. The term “about”, in the context of numeric values, generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (i.e., having the same function or result). In many instances, the term “about” may include numbers that are rounded to the nearest significant figure. Other uses of the term “about” (i.e., in a context other than numeric values) may be assumed to have their ordinary and customary definition(s), as understood from and consistent with the context of the specification, unless otherwise specified. The recitation of numerical ranges by endpoints includes all numbers within that range, including the endpoints (e.g. 1 to 5 includes 1, 1.5, 2. 2.75, 3, 3.80, 4, and 5). 
     It is noted that references in the specification to “an embodiment”, “some embodiments”, “other embodiments”, “various embodiments”, etc., indicate that the embodiments) described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is, described in connection with an embodiment, it would be within the knowledge of one skilled in the art to effectuate such feature, structure, or characteristic in connection with other embodiments, whether or not explicitly described, unless clearly stated to the contrary. That is, the various individual elements described below, even if not explicitly shown in a particular combination, are nevertheless contemplated as being combinable or arrange-able with each other to form other additional embodiments or to complement and/or enrich the described embodiment(s), as would be understood by one of ordinary skill in the art. 
     Referring to  FIG. 1 , an illustrated foot  100  is oriented generally isometrically. A three-dimensional coordinate system is overlaid through the foot  100 . A z-axis  104  extends through the foot, through the tibia  106 , and generally perpendicular to a ground surface (not illustrated). A y-axis  108  extends through the z-axis  104  and extends along a length of the foot  100 . The y-axis  108  may be generally perpendicular to the z-axis  104  when the foot  100  is positioned in a substantially flat position parallel with on resting on a ground surface. An x-axis  112  extends through the apex of the z-axis  104  and the y-axis  108  and extends generally perpendicular to a plane created by the z-axis  104  and the y-axis  108 . A rotation about the z-axis  104  may describe a motion of the body generally in the direction of the arrows  106 . A rotation about the y-axis  108  may describe a motion of the body generally in the direction of the arrows  110 . A rotation about the x-axis  112  may describe a motion of the body generally in the direction of the arrows  114 . 
     As used herein, the term “z-axis rotation” or “z-rotation” are interchangeable and refer to a rotation substantially about a z-axis unless clearly stated otherwise. The same relationships apply with the terms “y-axis rotation”, “y-rotation”, “x-axis rotation”, and “x-rotation” with respect to the y-axis and x-axis, respectively. 
     Rotation about an axis may not refer to just a rotation strictly about the axis, but also to simultaneous rotations about any another axis. Such axes defined throughout this disclosure may be repositioned as the insole, midsole, outsole, and/or foot move. For example, as the foot moves or a midsole is positioned such that it is not parallel with a ground surface, a y-axis may continue to extend along a foot, but the y-axis may no longer be substantially perpendicular to the z-axis. As a sole and/or a foot is positioned or moves, the axes move/re-orient along with the sole and/or foot. 
     Referring to  FIGS. 2A-2E , an embodiment of a rotatable midsole ambulatory footwear device is illustrated including a primary outsole  200  with a top side, a bottom side, a front end, and a back end. The footwear device further includes a secondary outsole  222  with a top end and a bottom end, and an elongate body  216  with a front end and a back end. The back end of the primary outsole  200  is connected to the secondary outsole  202  between the top and bottom ends of the secondary outsole  202 . More specifically, the back end of the elongate body  216  is connected to the secondary outsole  202  between the top and bottom ends of the secondary outsole  202 , and the primary outsole  200  is connected proximate to the front end of the elongate body  216 . The primary outsole  200  has a primary cavity  206  at the top side and the front end of the primary outsole  200 , and the secondary outsole  202  has a secondary cavity  208  at the top end of the secondary outsole  202 . A midsole  210  is movably disposed over the top side of the primary outsole  200  and the top end of the secondary outsole  202 . The midsole  210  includes, a top side, a bottom side, a front end, and a back end. The midsole  210  further includes a primary protrusion  212  proximate to the front end that protrudes away from the bottom side of the midsole  210 . The primary protrusion  212  extends at least partially within the primary cavity  206  when the bottom side of the midsole  210  engages the top end of the secondary outsole  202 . The primary protrusion  212  has a radius that is substantially the same as, or smaller than, a radius of the primary cavity  206 . The midsole  210  also includes a secondary protrusion  214  proximate to the back end of the midsole  210  that protrudes away from the bottom side of the midsole  210 . The secondary protrusion  214  extends at least partially into the secondary cavity  208  when the bottom side of the midsole  210  engages the top side of the primary outsole  200 . The secondary protrusion  214  has a radius that is substantially the same as, or smaller than, a radius of the secondary cavity  208 . The protrusions  212 ,  214  may extend partially into the cavities  206 ,  208  when no weight and/or force, is placed on the midsole  210 . The protrusions  212 ,  214  may extend more substantially into the cavities  206 ,  208  when weight and/or force is applied to the midsole  210 . The device defines a z-axis Z through the secondary cavity  208  and substantially normal to a ground surface, a y-axis Y extending substantially from the secondary cavity  208  to the primary cavity  206 , and an x-axis X substantially normal to a plane created by the z-axis Z and the y-axis Y. The midsole  210  includes a tertiary outsole  204  portion at the front end of the midsole  210  and about either side of the primary protrusion  212  positioned radially from the y-axis Y. One or more outsole arms  218  extend from the elongate body  216  at the front end of the elongate body  216  and extends about the primary cavity  206  such that the arms  218  are positioned radially from the y-axis Y. The bottom side of the midsole  210  includes one or more midsole arms  224  at the front end of the midsole  210  that extend along the bottom side of the midsole  210  and extend about the primary protrusion  212 . The midsole arms  224  reside above the top side of the outsole arms  218 . Outsole ribs  220  are disposed on the top end of the secondary outsole  202 . The outsole ribs  220  extend radially outward from the secondary cavity  208  and increase in height as the outsole ribs  220  extend radially outward away from the secondary cavity  208 . midsole ribs  222  are disposed on the bottom side and the back end of the midsole  210  In this embodiment, the midsole ribs  222  extend radially outward from the secondary protrusion  214 . The central midsole ribs  222  are disposed adjacent to and between the outsole ribs  220 , and may or may not make contact with the outsole ribs  220  when there is no midsole  210  rotation. The interaction between the midsole ribs  222  and outsole ribs  220  provide a means to substantially prevent rotation of a wearer&#39;s foot about the z-axis Z (as shown in  FIG. 1 ), but does not prevent rotation in about the X or Y axes. 
     Referring to  FIGS. 3A and 3B , an embodiment of a rotatable midsole ambulatory footwear device is illustrated including a primary protrusion  312  and a secondary protrusion  314  of a midsole  310  within a primary cavity  306  of a primary sole  300  and a secondary cavity  308  of a secondary sole  302 , respectively. The protrusions  312 ,  314  are free to rotate and/or slide about the x-axis X and/or the y-axis Y (substantially perpendicular to these cross-sectional views). The midsole ribs  322  may interact with outsole ribs to restrict over-rotation about the x-axis or y-axis by contacting the top portion of the secondary sole  302 . Additionally, the midsole arms  324  and/or the lip  326  prevent over-rotation of the midsole  310  about the x-axis X or y-axis Y by a midsole arm  324  contacting and stopping at the lip  326 . The rotation of midsole  310  about the z-axis Z is substantially prevented by the adjacency of the midsole ribs  322  with the outsole ribs. A rotation about the z-axis Z will be substantially prevented by the midsole ribs  322  coming into contact with and stopping at the outsole ribs. 
     In various embodiments of this disclosure, a midsole is able to rotate about an x-axis and/or about a y-axis with respect to a primary and secondary outsole. The midsole may rotate (e.g., “rock”) about the y-axis via rotation of the protrusions within the cavities and the ribs rocking along the top portion of a secondary sole. The midsole may also rotate about the x-axis by the protrusions sliding within the cavities such that the primary protrusion slides slightly towards the secondary cavity in one rotational direction about they-axis, and the secondary protrusion slides slightly towards the primary cavity in an opposite direction about the x-axis. A midsole is substantially prevented from rotating about a z-axis by the adjacency and interaction of the complementary ribs (or other similar protrusions or means) on the midsole and outsole. For example, when a rotational movement is made about the z-axis, the midsole and outsole ribs or other similar means make contact with each other and prevent further rotation. 
     In various embodiments, a tertiary outsole of a midsole may interact with a ground surface when the midsole is rotated about the x-axis and/or the y-axis and/or the ground surface slopes or is otherwise brought closer to one or more portions of the tertiary outsole. In addition to the primary and secondary outsoles, the tertiary outsole contacting the ground surface may assist a user in providing a third contacting point with the ground surface to perform the S-shape pathway of a step. Additionally, or in the alternative, the tertiary outsole may make contact with an outsole arm. 
     Referring to  FIGS. 4A and 4B , an embodiment of a rotatable midsole ambulatory footwear device is illustrated including a primary outsole  400  without outsole arms extending from the elongate body  416  and about the primary cavity  406 . This embodiment includes a smaller primary outsole  400  point of contact, allowing for a larger portion of the tertiary outsole  404  of the midsole  410  to make contact with the ground surface when rotated. Three points of ground contact may be established with the primary outsole  400 , secondary outsole  402 , and the tertiary outsole  404 . 
     Referring to  FIGS. 5-12 , various, embodiments of a rotatable midsole ambulatory footwear device are illustrated that include a midsole that is part of or integrated with an insole and other material to wrap about a foot for the function of holding the soles to the foot and/or for fashionable appeal. A pitch angle of a y-axis extending through the primary cavity and secondary cavity may be steepened with respect to a ground surface in order to fit with the shape of the midsole. For example, the y-axis extending through the cavities of the footwear of  FIG. 6  is steeper than that of the footwear of  FIG. 12 . With the adjustment of the pitch and length of the y-axis between and through the cavities, the top portion of the secondary outsole, the outsole ribs, and the midsole ribs may be extended or shortened to interface with the midsole. In addition to the footwear styles illustrated, various other footwear for ground-contacting limbs may be applied to or integrated with a midsole such as, for example, a high heel, a boot, a cleat, a prosthetic leg, a flat or other shoe, a robotic limb, a sneaker, an ambulatory cast, an athletic shoe, or the like. 
     In various embodiments, a midsole may be attached to an outsole. The midsole and outsole may be attached to each other via a flexible foam layer and/or flexible glue between the two. Additionally, or in the alternative, an elastomer thermoplastic polyurethane, thermoplastic rubber, ethylene-vinyl acetate, or the like may be disposed between a midsole and an outsole (e.g., at least between the midsole ribs and outsole ribs). Such materials between the midsole and outsole may leave open air pockets or an open-air layer between or within the materials to allow for additional compression from the weight and/or force of a user&#39;s foot. Additionally, or in the alternative, the midsole may be over-molded or co-molded onto the outsole, e.g., a molded rigid outsole may have a midsole injection molded about the outsole such that the midsole is generally adhered to the outsole while still remaining rotatable with respect to the outsole. The molded outsole may include poles, dowels, pins, lugs, trusses, teeth or the like on the upper portions of the outsole for the midsole to permanently or reversibly attach to via, e.g., complementary cavities or holes in the midsole to interact with these outsole features. A midsole may be reversibly attached to the outsole by using these features such that a midsole may reversibly “snap on” and “snap off” of an outsole to interchange the midsole or outsole for function and or fashion. In various embodiments, outsole portions may comprise of rubber, polymers, carbon fiber, plastics, a combination of these, or the like. 
     Referring to  FIGS. 13A and 13B , an embodiment of a rotatable midsole ambulatory footwear device is illustrated including a rigid primary outsole  1300  having primary arms  1304  and a rigid secondary outsole  1302  having secondary arms  1306 . Although two arms are illustrated for each of the primary and secondary arms  1304 ,  1306 , it should be understood that any number of arms  1304 ,  1306  may be implemented. For example, additional arms may allow for additional flexibility when interfacing at an angle with a ground surface. The midsole  1310  is disposed over and connected to the primary outsole  1300  and the secondary outsole  1302  at a point  1330  The footwear apparatus defines a z-axis Z through the point  1330  and substantially normal to a ground surface. A y-axis Y extends through the point  1330 , substantially along the midsole  1310 , the primary outsole  1300 , and the secondary outsole  1302 . The point  1330  may include a protrusion that interacts with a cavity of the primary outsole and secondary outsole, similar to that of the protrusion  214  and the cavity  208  of  FIG. 2C . Midsole ribs and outsole ribs may be disposed about the protrusion of the point  1330  to assist with substantially limiting z-rotation. An x-axis X is substantially normal to a plane created by the z-axis Z and the y-axis Y. The two arms  1304  of the primary outsole  1300  and the two arms  1306  of the secondary outsole  1302  may spread apart from each other in the tilted position  1360  (compared to the upright position  1350 ) along (not about) the z-axis Z. In this way, the arms  1304 ,  1306  may make an additional point of contact with the tilted ground surface. One or more outsole ribs may be disposed on the secondary outsole  1302  that may extend radially outward from about the point  1330 . Additionally, one or more midsole ribs maybe disposed on a bottom portion of the midsole  1310  extending radially outward from the point  1330 . The midsole ribs may be adjacent to the one or more outsole ribs. The midsole may include a tertiary outsole that interacts with a ground surface during rotations. 
     Referring to  FIG. 14 , an embodiment of a rotatable midsole ambulatory footwear device is illustrated including a midsole  1410  disposed over a primary outsole  1400  and a secondary outsole  1402 . The midsole  1410  includes a primary cavity  1406  and a secondary protrusion  1414 . A primary protrusion  1412  extending from the primary outsole  1400  extends at least partially into the primary cavity  1406 . The secondary protrusion  1414  extends at least partially into a secondary cavity  1408  in the secondary outsole  1402 . The midsole  1410  is moveable with respect to the outsoles  1400 ,  1402  via the protrusions  1412 ,  1414  and cavities  1406 ,  1408 . A flexible material  1420  between the midsole  1410  and the outsoles  1400 ,  1402  fills in the space between the soles while still permitting movement of the soles. The secondary outsole  1402  has an extension  1430  that extends, in a substantially posterior direction with an upward curve such that when a wearer takes a running step that would naturally involve a back edge of the naked heel to contact the ground first, instead a larger amount of surface area of the extension  1430  can interface with the ground. Lights, e.g., in the form of a laser  1432 , may be disposed on the extension  1430 . A battery for the laser  1432  may be housed within the extension  1430 . The laser  1432  may be oriented in a multitude of directions, e.g., up at the wearer, out over a crowd from a staged position of the wearer, or the like. The midsole  1410  may include a suspension portion  1434  that comprises a different material or a lack of any material at all (i.e., a pocket) that may align with portions of a foot of the wearer (e.g., the tuberosity of the fifth metatarsal). The extension  1430  may comprise a multitude of shapes including, e.g., an ellipsoid, a square, a trapezoid, a stemmed wine glass, tree roots, a combination thereof, or the like. 
     Referring to  FIG. 15 , an embodiment of a rotatable midsole ambulatory footwear device is illustrated including a primary outsole  1500  having an outsole rib  1520  about the primary cavity  1506 . This outsole rib  1520  is about the primary protrusion  1512  and is adjacent to a midsole rib  1522  of the midsole  1510 . These ribs  1520 ,  1522  are in alternative to ribs that may be disposed about the secondary cavity  1508  and the secondary protrusion  1514 , however, these ribs  1520 ,  1522  may be in addition to ribs about the secondary cavity  1508  and secondary protrusion  1514 . The relationship between these midsole ribs  1522  and outsole ribs  1520  functions similarly to midsole ribs and outsole ribs described herein. 
     Referring to  FIG. 16 , an embodiment of a rotatable midsole ambulatory footwear device is illustrated including a secondary outsole  1602  having a primary cavity  1606  at a side portion and a secondary cavity  1608  at a top portion. A midsole  1610  is disposed over the secondary outsole  1602 . A secondary protrusion  1614  extends from the midsole  1610  at least partially into the secondary cavity  1608 . The midsole  1610  extends to and is continuous with a primary outsole  1600 . An elongate body  1616  extends from the primary outsole  1600  toward the primary cavity  1606  of the secondary outsole  1602 . A primary protrusion  1612  is disposed at an end of the elongate body  1616 . The primary protrusion  1612  extends at least partially within the cavity  1606 . A z-axis Z is defined through the secondary cavity  1608  and substantially normal to a ground surface. A y-axis Y extends substantially from the secondary cavity  1608  through the primary protrusion  1600 . An x-axis X extends substantially normal to a plane created by the z-axis Z and the y-axis Y. The primary protrusion  1612  is a pin that is rotatably engaged with the primary cavity  1606 . The primary protrusion  1612  pin, the elongate body  1616 , and by extension the midsole  1610  is able to rotate about the y-axis Y. The primary protrusion  1612  pin is also reversibly engageable within the primary cavity  1606  about the x-axis X. The outsole ribs  1620  adjacent with the midsole ribs  1622  prevent substantial rotation about the z-axis Z. 
       FIGS. 17A through 17D  illustrate an embodiment of a rotatable midsole ambulatory footwear device including a unibody sole  1730 . The unibody sole  1730  includes a posterior outsole portion  1702  that has a cavity  1708 . A midsole portion  1710  is disposed on a top portion  1726  of the posterior outsole portion  1702 . The midsole portion  1710  extends away from the posterior outsole portion  1702 . An anterior outsole portion  1700  extends from a bottom portion  1728  of the midsole portion  1710 . An elongate body  1716  extends from the anterior outsole portion  1700  toward the posterior outsole portion  1702 . A protrusion  1714  is disposed at an end of the elongate body  1716 . The protrusion  1714  extends at least partially within the cavity  1708 . The unibody sole  1730  defines a z-axis Z through the cavity  1708  and substantially normal to a ground surface. A y-axis Y extends substantially from the cavity  1708  through the elongate body  1716  and the primary outsole portion  1700 . An x-axis X extends substantially normal to a plane created by the z-axis Z and the y-axis Y. The protrusion  1714  is pin that is rotatably engaged with the cavity  1708 . The elongate body  1716 , and by extension the midsole  1710  is able to rotate about the y-axis Y. The protrusion  1714  pin is also reversibly engageable within the cavity  1708  about the x-axis X. The single cavity  1708  engaging the protrusion  1714  pin prevents substantial rotation about the z-axis Z. The protrusion  1714  pin may be of any controlled swivel action configuration, such as a reversable female/male ball and socket mechanism, as illustrated in  FIG. 17B .  FIGS. 17C-17D  further illustrate a protrusion  1740  is connected to the front end of the elongate body  1716  and to a fork structure  1741  disposed on the ground-interfacing side proximate to the anterior outsole portion  1700 . In one embodiment, the fork structure  1741  and the protrusion  1740  are composed of two pieces,  1741   a - 1741   b  and  1740   a - 1740   b,  respectively. The protrusion  1740  allows the midsole portion  1710  to rotate about the x-axis X and the y-axis Y, while rotation about the z-axis Z is limited in the manner described above. The midsole portion  1710 , the posterior outsole portion  1702 , the anterior outsole portion  1700  can be of a rigid to semi-rigid material. 
     In various embodiments, the midsole and outsole ribs may instead be a midsole tooth extending into an outsole channel, or any other suitable complementary means. The tooth may freely move within the channel when rotating about the x-axis and about the y-axis, but may be locked when rotating about the z-axis by the tooth colliding with the sidewalls of the channel. The ribs or other z-rotation prevention feature may comprise, for example, a firm compression material such as ethylene-vinyl acetate (EVA) of about 30 durometer to about 50 durometer to allow some compression without compromising the rotational function of the midsole. 
     In various embodiments, a primary protrusion and a tertiary outsole may be positioned to avoid a fifth metatarsal of a wearer&#39;s foot disposed over a midsole. Positioning these anterior ground-interfacing soles such that they avoid these portions of the foot may allow for comfortable eversion movement in a step. 
     In various embodiments, an elongate body may be thin and flexible to succumb to desirable warping about the x-axis and/or y-axis. Warping of the elongate body may include twisting that assists with rotation of a midsole. The elongate body may comprise many bodies such as e.g., a leaf spring, a series of plates, a series of discs, or the like. 
     Various embodiments herein may include features that allow for sole flexibility, compression, and/or ground traction with a complete lack of or a substantial lack of soft materials or features such as foam, gels, springs, or the like. Such soft materials in footwear may not allow for proper foot alignment during movement. It may be desirable to provide flexibility, compression, and/or traction solely using rigid and/or semi-rigid materials for proper foot support and alignment. 
     Referring to  FIG. 18 , a side cross-sectional view of an embodiment of a rotatable midsole ambulatory footwear device is illustrated including a stud  1814  that engages a midsole  1810 . The engagement portion  1812  of the stud  1814  engages the locking ring  1806  of the midsole  1810 . This the stud  1814  may be locked into the locking ring  1806 , which may be reversible (e.g., snapped in) or the stud  1814  may be co-molded or over-molded with the locking ring  1806 . The stud  1814  includes two flex joints  1816  that extend away from the stud  1814  into outsoles  1800  that may engage a ground surface. During compression of the midsole  1810  onto the stud  1814 , a traction stud potion  1804  of the stud  1814  may engage the ground surface for additional traction. The flex joints  1816  are free to bend to allow for flexibility when the outsoles  1800  engage a ground surface without the need for additional soft materials. The flex joints  1816  also provide resistance to a weight or force from the midsole  1810  (e.g., a cushioning resistance against a user&#39;s foot during a step motion). 
     Referring to  FIG. 19A , a side cross-sectional view of an embodiment of a rotatable midsole ambulatory footwear device is illustrated including a curved arm  1910  including a flexible outsole  1900 . This flexible outsole  1900  is curved into a generally “W” shape in the resting position. The ends of the outsole  1900  are slidingly attached to the arm  1910  via the slide lugs  1912  that are free to slide along a channel within the arm  1910 . When the arm  1910  is compressed downwardly in the direction of the arrow D, the fixed point  1904  of the outsole  1900  moves down in the direction of the arrow D while the bottom portions of the “W” outsole  1900  move outwardly in the direction of the arrows O. Additionally, the ends of the “W” outsole  1900  attached to the slide lugs  1912  move outwardly along the arrows S. The result is a compressed outsole  1900  that brings the arm  1910  closer to the ground surface. The compressed outsole  1900  provides resistance to the aim  1910  to support the wearer&#39;s foot without the use of soft materials.  FIG. 19B  illustrates the structure of  FIG. 19A  incorporated between the front end of the primary outsole  1920  and the tertiary outsole  1921 . As a wearer&#39;s foot moves and compressed downwardly on the tertiary outsole  1921  in the direction of arrow D, the bottom portions of the “W” outsole  1900  moves outwardly in the direction of the arrows O (see  FIG. 19A ). Proximately to the slide lugs  1912  are one or more pressure sensors  1922  for tracking motions along the x-axis X and the y-axis Y. A central motion sensor  1923  is disposed within the footwear device for collecting data captured by the pressure sensor  1922 . For example, the central motion sensor  1923  may be attached to the primary protrusion 1924  but may be attached elsewhere. Additionally, the slide lugs  1912  may provide kinetic energy to a battery  1925  for storing power within a sole. The power stored in the battery  1925  may be used to power another device, such as a laser  1926 . Although a “W” shape is illustrated for the outsole  1900 , other shapes may be implemented, for example, any number of valleys making contact with the ground surface. The data captured by the sensors  1922  and  1924  may be transmitted to another device for processing, such as a software application executable on a computer, a mobile phone, headphones, sensory gloves, work out bars, knee/ankle sleeves, and any body attachment gear. These devices interpret the, data and triggers a corresponding action. For example, an alarm can be triggered to alert the wearer of alignment issues between the wearer&#39;s foot and another part of the body and/or among multiple parts of the body. 
     Referring to  FIG. 20 , a side cross-sectional view of an embodiment of a rotatable midsole ambulatory footwear device is illustrated including a piston  2014  within a heel portion of a midsole  2010 . Under compression, the piston  2014  may translate in a downward direction of the arrow D. The piston  2014  meets resistance in the downward motion by compressing and/or forcing a fluid  2060  through the fluid channels  2062  and into the accumulator sphere  2068 . The accumulator sphere  2068  includes a diaphragm  2064  that flexes between and separates the fluid  2060  from a pressurized air chamber  2066  in the accumulator sphere  2068 . In this way, the midsole  2010  may transfer a downward force to the piston  2014 , which transfers the force to the fluid  2060 , which transfers the force to the diaphragm  2064 , which transfers the force to the compressible gas in the air chamber  2066 . As such, a comfortable compressive resistance may be enjoyed by the wearer without the use of soft materials. The heel piston  2014  may act similarly to that of the protrusions and cavities described herein. Although illustrated in the heel, such a system may be included in the anterior portion of a foot apparatus. 
     Referring to  FIGS. 21A-21C , a side cross-sectional view of an embodiment of a rotatable midsole ambulatory footwear device is illustrated including a midsole  2110  having a trapezoidal protrusion  2112 . The protrusion  2112  extends toward a diaphragm  2106  attached to a locking ring  2107 . The locking ring  2107  extends to a primary and secondary sole  2100 ,  2102 . The diaphragm  2106  is in a resting state in  FIG. 21A . If the midsole  2110  is compressed with enough force towards the ground substantially in a direction of the arrow D (e.g., by a wearer stomping or landing flat on their feet), the protrusion  2112  may extend into and deform the diaphragm  2106  like that shown in  FIG. 21B . The diaphragm  2106  may provide resistance to the protrusion  2112 , midsole  2110 , and the wearer&#39;s foot without the use of soft, materials. The protrusion  2112  in combination with the diaphragm  2106  may be forced into substantially flat contact with the ground, providing an additional traction contact point for the wearer. In a substantially forward motion in the direction of arrow R (e.g., running motion) in  FIG. 21C , a front portion  2109  of the protrusion  2112  may be forced into the diaphragm  2106 . The resulting combination of the front portion  2109  deforming the diaphragm  2106  may result in a substantially triangular shape  2111  of the diaphragm  2106  contacting the ground for additional traction. 
     In various embodiments, one or more material layers may be disposed between, about, and/or within the protrusions of the midsole and the cavities of the primary and secondary outsoles. The material may be flexible to hold the midsole to the outsoles while permitting movement between the two. Such materials may include EVA, nylon, foam, thermoplastic polyurethane, rubber, a combination of these materials, or the like. Pockets of air may be located within these materials for comfort areas of compression. Such areas may be located substantially adjacent to a tuberosity of a fifth metatarsal, a fifth metatarsal head, a first metatarsal head, a brevis tendon, a calcaneus, and/or the like. Such areas may allow for the lowering of such anatomical portions of the foot during a step. Lowering of these areas, bones, and or tendons of the foot may increase blood flow from the foot and up the leg by aligning the foot with the leg and by increasing blood pressure returning through the associated veins. Aligning the foot and leg may better align associated veins, for easier return of blood from the foot. The lowering of the previously mentioned areas of the foot may raise the mid-section of the foot, increasing blood pressure in the associated veins to pump blood up through the leg. Additionally, rotation of the foot about the x-axis and the y-axis in this position may assist with this pressure for blood to work through the veins and up the wearer&#39;s leg. A midsole may have a semi-rigid to rid foot interfacing surface and a more resilient outsole and/or ground interfacing surface. Such areas may be located, e.g., in an arm of an outsole. Specifically, for example, a relief area may be located in a sole adjacent to (e.g., below) the brevis tendon (near and/or at the ball of the pinky toe) such that when the midsole lifts the heel (e.g., in a high-heeled shoe), the bones and tendons about the ball of the pinky toe are allowed to be lowered to not disrupt joint alignment. A wrap or band about a portion of the compressible material (e.g., about a heel portion of a sole) may control the density of the compressible material by tightening or loosening the wrap via, e.g., a set screw, nut, or the like. 
     Certain embodiments of the present invention include a more reliable process for manufacturing footwear that reduces labor. A conventional approach is to use injection molding or to cast shoe soles. An upper is then glued or stitched to the sole. However, this conventional approach, is labor intensive and has a potentially high rate of rejections for footwear that do not meet requirements. In the manufacturing process according to the present invention, the upper is attached during the midsole manufacturing stage, eliminating the steps of stitching or the potentially environmentally hazardous and costly gluing steps. Referring to  FIGS. 22 and 23 , the manufacturing process according to the present invention uses a tool that comprises a midsole mold, the midsole mold having a bottom portion  2201  and a top portion  2301 . The bottom portion  2201  of the midsole mold has a cavity  2204 . The footwear upper material A-C is placed onto the bottom portion of the midsole mold  2201 . A first portion A of the upper material resides within the cavity  2204  of the bottom portion of the midsole mold  2201 . A second portion B-C of the upper material extends beyond the boundaries of the cavity  2204  of the bottom portion of the midsole mold  2201  to which additional upper material is attached or with enough material to allow the second portion B-C to form the footwear upper. Pins  2302  or other retention means may be used with the bottom portion of the midsole mold  2201  to adjust the tension of the upper material A-C to avoid wrinkling of the upper material A-C when the midsole is molded. The tension may vary from heel to toe to eliminate wrinkles of the upper material A-C. The top portion of the midsole mold  2301  closes down onto the bottom portion of the midsole mold  2201 , and midsole material is injected into the midsole mold to form the midsole  2202 . This fuses the first portion of the upper material A to the midsole  2202  without the need for stitching, or gluing. Textile or any impregnable material can be placed in the midsole mold in a manner that the material is impregnated with a moldable material such as but not limited to thermoplastic polyurethane (TPU), thermoplastic rubber (TPR), Nylon and or any other material that is moldable to impregnate textile to form a bond that is strong. The second portion of the upper material B-C is then formed along the circumference  2203  of the midsole  2202  to construct the sidewalls of the footwear. Alternatively, the second portion of the upper material B-C is used to construct straps or a circumference wrap to which additional upper material is attached. For example, the fabric may be wrapped, tied, buckled, laced, or the like. A flexible material E, e.g. cloth fabric, and/or a rigid or semi-rigid material D, e.g. carbon fiber, may be used as the upper material A-C. The manufacturing process may be used to form an outsole, where impregnable material may be used as the upper material. The manufacturing process may also be used to form an insole, where impregnable material may be used to form a sock or liner for the footwear. The midsole may be formed such that the circumference of the midsole forms a tertiary outsole attached to a primary and secondary outsole. The midsole mole may also have a series of passthrough voids in the tertiary outsole section to form at least one ground contacting protrusion. 
     While certain embodiments of the present invention are described herein. It is, however, expressly noted that the present invention is not limited to these embodiments, but rather the intention is that additions and modifications to what was expressly described herein are also included within the scope of the invention. Moreover, it is to be understood that the features of the various embodiments described herein are not mutually exclusive and can exist in various combinations and permutations, even if such combinations or permutations are not made expressly herein, without departing from the spirit and scope of the invention. In fact, variations, modifications, and other implementations of what is described herein will occur to those of ordinary skill in the art without departing from the spirit and the scope of the invention. As such, the invention is not to be defined only by the illustrative description herein.