HK1222518B - Auxetic structures and footwear with soles having auxetic structures - Google Patents

Description

Auxetic structure and footwear having a sole with the same

background

Articles of footwear typically have at least two main components: an upper that provides an outer shell for receiving the wearer's foot, and a sole that is secured to the upper and is the primary contact portion that contacts the ground or court surface. Footwear may also utilize some type of fastening system, such as laces or straps, or a combination of the two, to secure the footwear around the wearer's foot. The sole may comprise three layers: an insole, a midsole, and an outsole. The outsole is the primary contact member that contacts the ground or court surface. The outsole typically has a ground pattern and/or cleats or spikes or other protrusions that provide the wearer of the footwear with improved traction suitable for a particular competitive, work, or leisure activity, or for a particular ground surface.

Overview

As used herein, the term "auxetic structure" generally refers to a structure that, when placed under tension in a first direction, increases in a dimension orthogonal to the first direction. For example, if the structure can be described as having a length, a width, and a thickness, then when the structure is tensioned in the longitudinal direction, its width increases. In certain embodiments, the auxetic structure is bidirectional, such that the structure increases in length and width when stretched in the longitudinal direction and increases in width and length when stretched in the transverse direction, but does not increase in thickness. Such auxetic structures are characterized by having a negative Poisson's ratio. Additionally, while such structures will generally have at least a monotonic relationship between an applied tensile force and an increase in a dimension orthogonal to the direction of the tensile force, this relationship need not be proportional or linear and generally only needs to increase in response to an increasing tensile force.

An article of footwear includes an upper and a sole. The sole may include an insole, a midsole, and an outsole. The sole includes at least one layer made of an auxetic structure. This layer may be referred to as an "auxetic layer." When a person wearing the footwear engages in activities that place the auxetic layer under increased longitudinal or lateral tension, such as running, turning, jumping, or accelerating, the auxetic layer increases in length and width, thereby providing improved traction and absorbing some of the impact with the playing surface. Although the following description discusses only a limited number of types of footwear, embodiments may be suitable for many sports and recreational activities, including tennis and other racquet sports, walking, jogging, running, hiking, handball, training, running or walking on a treadmill, and team sports such as basketball, volleyball, lacrosse, field hockey, and soccer.

In one aspect, an article of footwear includes an upper and a sole structure. The sole structure includes an outsole, wherein the sole structure has a first direction tangential to an outer surface of the outsole and the sole structure has a second direction orthogonal to the first direction, wherein the second direction is also tangential to the outer surface of the outsole. The sole structure also includes a plurality of apertures arranged in a geometric pattern. Tensioning the sole structure in the first direction causes the outsole to expand in both the first and second directions.

The article of footwear also includes a midsole having a midsole geometry that cooperates with the geometry of the outsole.

The geometric pattern includes a polygonal portion of the outsole surrounding the plurality of apertures.

The polygonal parts are connected to each other by joints, which serve as hinges that allow the polygonal parts to rotate relative to each other.

The polygonal portion is a triangular portion.

When the sole structure is not under tension, the plurality of apertures are closed.

When the sole structure is under tension, the plurality of apertures are open.

At least one of the plurality of apertures is open when the sole structure is not under tension and is not under vertical compression, and is closed when the sole structure is under vertical compression.

The article of footwear also includes an exterior covering extending over the outsole.

The sole structure has a ground contact pattern.

The geometric pattern is a hexagonal pattern.

The sole structure includes an auxetic foam material.

In another aspect, a sole structure for an article of footwear includes an outsole having a structure consisting of a hexagonal pattern. The outsole defines a plane. The hexagonal pattern includes a polygonal aperture surrounded by triangular portions connected to each other by joints that function as hinges that allow the triangular portions to rotate relative to each other. When the outsole is pulled in a first direction, the outsole expands in both the first direction and a second direction orthogonal to the first direction and within the plane of the sole structure.

The sole structure also includes a midsole having a geometry that cooperates with the geometry of the outsole.

The polygonal apertures are each surrounded by six triangular portions.

The polygonal aperture is characterized by having concave angles on sides of the polygonal aperture comprising between approximately 100° and 170°.

The outsole has a heel region and an instep region, and wherein the hexagonal pattern includes hexagonal features that are significantly larger in the heel region than in the instep region.

The sole structure also includes an exterior covering extending over the outsole and attached to the outsole.

The exterior covering includes a hexagonal pattern that is complementary and mates with the hexagonal pattern in the outsole.

The outsole is a molded polymer material.

The hexagonal pattern is produced by molding the molded polymer material to produce the hexagonal pattern.

The polygonal aperture includes a through hole.

The polygonal aperture comprises a blind hole.

The polygonal apertures are closed when the outsole is not under tension, and at least one of the polygonal apertures is open when the outsole is under tension either laterally or longitudinally.

In another aspect, an article of footwear includes an upper and a sole structure, wherein the sole structure includes an outsole characterized by a polygonal portion surrounding a polygonal aperture. The polygonal portion is hingedly connected to adjacent polygonal portions such that the polygonal portions rotate relative to each other when the sole structure is subjected to tension. When a portion of the outsole is subjected to longitudinal tension, the outsole expands in both the longitudinal and transverse directions, and when a portion of the outsole is subjected to transverse tension, the outsole expands in both the transverse and longitudinal directions.

The sole structure further includes a midsole having a structure that cooperates with the structure of the outsole.

The polygonal part is a triangular part.

The sole structure also includes an exterior covering attached to a bottom surface of the outsole.

The polygonal aperture has a center, and wherein when the sole structure is subjected to vertical compression, the polygonal portion is urged toward the center of the polygonal aperture.

The outsole is attached to the upper by overmolding the outsole to the upper.

On the other hand, an article of footwear includes an outsole comprising a pattern of polygonal openings formed by triangular portions surrounding the polygonal openings. The polygonal openings have a center. The triangular portions are connected at their vertices so that the vertices act as hinges, thereby allowing the triangular portions to rotate relative to each other. The outsole is characterized by having a transverse direction, a longitudinal direction, and a vertical direction. When a portion of the outsole is stretched transversely, it expands in both the transverse and longitudinal directions, and when a portion of the outsole is stretched longitudinally, it expands in both the longitudinal and transverse directions. When a portion of the outsole is subjected to vertical compression, the triangular portions are pushed toward the center of the polygonal opening.

The article of footwear has a heel region, and wherein the pattern of polygonal apertures extends through the heel region.

The outsole has medial and lateral sides and an instep area, and wherein the outsole includes a cut-away portion on the medial side of the instep area.

The outsole has a heel region and an instep region, and wherein the polygonal aperture is significantly larger in the heel region than in the instep region.

The outsole has a forefoot region, and wherein the polygonal aperture is larger in the forefoot region than in the instep region.

The outsole has a heel region, and wherein the polygonal aperture in the heel region is characterized by having a generally laterally oriented concave lateral side, and wherein the generally laterally oriented concave lateral side has a shallow concave angle.

The outsole has a forefoot region, and wherein the polygonal aperture in the forefoot region is characterized by having generally laterally oriented concave lateral sides, and wherein the generally laterally oriented concave lateral sides have sharp concave corners.

The outsole has a heel region, and wherein the heel region has a lateral side, a center side, and a medial side, and

Wherein the polygonal openings on the lateral side of the heel region and on the medial side of the heel region are significantly smaller than the polygonal opening in the center of the heel region.

In another aspect, an auxetic structure includes a pattern of polygonal apertures characterized by having at least three concave sides and a center. The auxetic structure has a longitudinal direction and a transverse direction, and a thickness. Under longitudinal tension, the auxetic structure expands in both the longitudinal and transverse directions. Under transverse tension, the auxetic structure expands in both the transverse and longitudinal directions. Under vertical compression, the polygonal apertures collapse toward the center.

The auxetic structure is made of an intrinsically auxetic material.

The intrinsically auxetic material comprises an intrinsically auxetic foam material.

The polygonal aperture is surrounded by polygonal sections connected to adjacent polygonal sections by flexible joints such that the polygonal sections can rotate relative to each other.

The polygonal aperture is surrounded by polygonal portions that are flexibly connected at their vertices to vertices of adjacent polygonal portions such that the polygonal portions rotate relative to each other when the auxetic structure is under tension.

The polygonal portion is triangular.

The size of the polygonal aperture in the first region of the auxetic structure is significantly larger than the size of the polygonal aperture in the second region of the auxetic structure.

The auxetic structure is a layered composite material comprising a first layer of relatively elastic material and a second layer of stiff material.

The auxetic structure further includes an outer covering having a pattern that cooperates with the pattern of polygonal apertures in the auxetic structure.

A plurality of the polygonal apertures have a first concave side characterized by a first concave angle between about 150° and 170° and a second concave side characterized by a second concave angle between about 110° and 130°.

The polygonal aperture is a triangular aperture.

In another aspect, the sheet has a longitudinal direction, a transverse direction, and a vertical direction. The sheet also includes a pattern of hexagonal structures having an aperture surrounded by triangular sections, wherein each triangular section is connected to an adjacent triangular section by a flexible joint so that the triangular sections can rotate relative to each other. When the sheet is stretched in the longitudinal direction, the sheet expands in both the longitudinal and transverse directions.

When the sheet is not under tension, the plurality of apertures are closed.

When the sheet is not under tension, the plurality of apertures are open.

The hexagonal structure has a center, and wherein when the sheet is vertically compressed, the triangular portions are urged toward the center of the hexagonal structure.

When the sheet is vertically compressed due to the impact, the density of the vertically compressed sheet increases.

The sheet has an auxetic structure.

The sheet material comprises an essentially auxetic foam material.

The aperture has three concave sides, and wherein each of the three concave sides has a concave angle between 110° and 170°.

In another aspect, a composite auxetic material includes a first layer of relatively stiff material, the first layer including a pattern of polygonal apertures surrounded by polygonal portions, wherein each polygonal portion is connected to adjacent polygonal features by a flexible joint such that the polygonal portions can rotate relative to each other when the first layer is subjected to tension. The material also includes a second layer of relatively elastic material attached to the first layer, wherein the second layer has the same pattern of polygonal apertures as the first layer, and wherein the pattern of polygonal apertures in the second layer is aligned with the pattern of polygonal apertures in the first layer. When the composite auxetic material is subjected to tension in a first direction, the composite auxetic material expands in both the first direction and a second direction orthogonal to the first direction.

The composite auxetic material further includes a third layer of flexible and elastic material attached to the second layer of elastic material on an opposite side of the second layer from the first layer.

The composite auxetic material further comprises an outer cover of a flexible and elastic material attached to the first layer on an opposite side of the first layer from the second layer.

The outer covering includes a pattern of polygonal features that protrude from a surface of the outer covering and mate with the polygonal apertures in the first layer.

The polygonal aperture has at least three concave sides, and wherein each of the three concave sides of the polygonal aperture has a concave angle between about 110° and about 170°.

A plurality of the polygonal apertures have one concave side with a concave angle between about 110° and 130° and another concave side with a concave angle between about 150° and 170°.

The polygonal orifice is a triangular star-shaped orifice.

The polygonal feature is a triangle feature.

Other systems, methods, features and advantages of the embodiments will be or will become apparent to one of ordinary skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description and this summary, be within the scope of the embodiments, and be protected by the following claims.

Brief Description of the Drawings

The embodiments may be better understood with reference to the following drawings and descriptions. The components in the drawings are not necessarily to scale, but emphasis is placed on the principles of the illustrated embodiments. In addition, in the drawings, like reference numerals denote corresponding parts throughout the different views.

1 is a schematic diagram of a side view of an embodiment of an example article of footwear having a sole with an auxetic structure;

FIG2 is a schematic diagram of a bottom perspective view of the embodiment of the article of footwear shown in FIG1 ;

FIG3 shows a series of schematic diagrams of a bottom view of a portion of the outsole of FIG1 in different tension states;

FIG4 is a schematic diagram of a top view of an embodiment of a shoe outsole with the upper removed;

FIG5 is a schematic diagram of a bottom view of the outsole shown in FIG4 ;

FIG6 is a schematic diagram of an enlarged view of the heel region of the outsole shown in FIG5 when it is not under tension;

FIG7 is a schematic diagram of a cross section along the line A-A marked in FIG6;

FIG8 is a schematic diagram of an enlarged view of the heel area shown in FIG5;

FIG9 is a schematic diagram of an enlarged view of the heel region shown in FIG5 when it is longitudinally stretched;

FIG10 is a schematic diagram of an enlarged view of the heel region shown in FIG5 when it is subjected to lateral tension;

FIG11 is a schematic diagram of an embodiment of a shoe sole when it is not under tension;

FIG12 is a schematic diagram of an enlarged view of the forefoot portion of the sole shown in FIG11 when it is laterally stretched;

FIG13 is a schematic diagram of an enlarged view of the forefoot portion of the sole shown in FIG11 when it is longitudinally stretched;

FIG14 is a schematic diagram of an enlarged view of the midsole portion of the shoe shown in FIG11 when it is longitudinally stretched;

FIG15 is a schematic diagram of an enlarged view of the midsole portion of the shoe shown in FIG11 when it is in an increased lateral tension state;

FIG16 is a schematic diagram of an enlarged view of the forefoot portion of the sole shown in FIG5 when it is not under tension;

FIG17 is a schematic diagram of an enlarged view of the forefoot portion of the sole shown in FIG5 when the forefoot portion is longitudinally stretched;

FIG18 is a schematic diagram of an enlarged view of the forefoot portion of the sole shown in FIG5 when it is laterally stretched;

FIG19 is a schematic diagram of a bottom view of an outsole portion of an embodiment of a shoe having ground-engaging members when it is not under tension;

FIG20 is a schematic diagram of a cross-section of the sole of the embodiment shown in FIG19;

FIG21 is a schematic diagram of a top view of a portion of the outsole shown in FIG19 when it is not under tension;

FIG22 is a schematic diagram of a top view of a portion of the outsole shown in FIG19 when it is under tension;

FIG23 shows a series of schematic diagrams of a bottom view of a portion of the outsole of FIG19 in different tension states;

FIG24 is a schematic diagram of a bottom view of the outsole of an embodiment when it is not under tension;

FIG25 shows a series of schematic diagrams of a bottom view of a portion of the outsole of FIG24 in different tension states;

FIG26 is a schematic diagram of another embodiment of a shoe outsole when it is not under tension;

FIG27 is a schematic diagram of the embodiment of the outsole shown in FIG26 when it is under tension;

FIG28 is a schematic diagram of a top view of an embodiment of an outer covering engaged with the outsole of the shoe of FIG26 ;

FIG29 is a schematic diagram showing how the outer cover of FIG28 cooperates with the outsole of FIG26;

FIG30 is a schematic diagram of a side perspective view of the outsole and outer covering of FIG28 and FIG29;

FIG31 is a schematic diagram of a cross-section of an exemplary configuration of a sole having the outsole of FIG26 and the outer covering of FIG28;

FIG32 is a schematic diagram of an embodiment of an article of footwear having a braided upper and an auxetic structured sole;

FIG33 is a schematic diagram of the outsole of the article of footwear of FIG32 showing the auxetic structure thereof;

FIG34 is a schematic diagram of a side perspective view of the article of footwear of FIG32;

FIG35 is a schematic diagram of an enlarged perspective bottom view of the heel of the article of footwear of FIG32;

FIG36 is a schematic diagram of an enlarged view of a midsole portion of the outsole of the article of footwear of FIG32;

FIG37 is a schematic diagram of the interior of the article of footwear of FIG32;

FIG38 is a schematic diagram of a cross-section of the article of footwear of FIG32 taken at the forefoot;

FIG39 is a schematic diagram of a side view of a running shoe having a braided upper including an auxetic sole structure;

FIG40 is a schematic diagram of a bottom view of the outsole of the article of footwear of FIG39;

FIG41 is a schematic diagram of an enlarged perspective bottom view of the forefoot region of the article of footwear of FIG39;

FIG42 is a schematic diagram of an enlarged perspective view of the heel of the article of footwear of FIG39;

FIG43 is a schematic diagram of a cross-section of the article of footwear of FIG39;

FIG44 is a schematic diagram of a side view of an additional embodiment of a shoe having an upper and an outsole having an auxetic structure;

FIG45 is a schematic diagram of the article of footwear of FIG44 within the heel area of the shoe;

FIG46 is a schematic diagram of a portion of an outsole having apertures in a non-compressed configuration; and

47 is a schematic diagram of a portion of an outsole having apertures in a compressed configuration.

Detailed description

For clarity, the detailed description herein describes a few exemplary embodiments, but the disclosure herein may be applied to any article of footwear that includes certain of the features described herein and recited in the claims. In particular, although the following detailed description discusses exemplary embodiments in the form of footwear such as running shoes, jogging shoes, tennis shoes, squash shoes, or cricket shoes, basketball shoes, sandals, and fins, the disclosure herein may be applied to a wide range of footwear.

For consistency and convenience, directional adjectives are used throughout this detailed description corresponding to the illustrated embodiments. As used throughout this detailed description and in the claims, the term "longitudinal" refers to the direction extending the length (or longest dimension) of an article of footwear, such as an athletic shoe or casual shoe. Furthermore, as used throughout this detailed description and in the claims, the term "transverse" refers to the direction extending along the width of the article of footwear. The transverse direction can generally be perpendicular to the longitudinal direction. As used throughout this detailed description and in the claims with respect to an article of footwear, the term "vertical direction" refers to the direction perpendicular to the plane of the sole of the article of footwear.

The term "sole structure," also referred to simply as "sole," will be used herein to refer to the surface that directly contacts the ground or playing surface and provides support and bearing for the wearer's foot, such as any combination of the sole alone; the combination of the outsole and insole; the combination of the outsole, midsole, and insole; and the combination of the outer covering, outsole, midsole, and insole.

FIG1 is a side perspective view of an embodiment of an article of footwear 100. Article of footwear 100 may include an upper 101 and a sole structure 102, hereinafter also referred to simply as sole 102. Upper 101 has a heel region 103, an instep or midfoot region 104, and a forefoot region 105. Upper 101 may include an opening or throat 110 that allows a wearer to insert his or her foot into the footwear. In some embodiments, upper 101 may also include a lace 111 that can be used to tighten or otherwise adjust upper 101 around the foot.

In some embodiments, sole 102 includes at least outsole 120, which can be the primary ground-contacting surface. In some embodiments, sole 102 also includes an insole, a midsole, or both. In some embodiments, outsole 120 can have a ground-engaging pattern or can have cleats, spikes, or other ground-engaging protrusions.

FIG2 is a bottom perspective view of an embodiment of an article of footwear. This figure shows the bottom portion of an outsole 120. Outsole 120 has a heel region 123, an instep or midsole region 124, and a forefoot region 125, as shown in FIG2 . Outsole 120 has an aperture surrounded by polygonal features connected at their vertices. The junctions at the vertices act as hinges, allowing the polygonal features to rotate when the sole is pulled downward. This action allows the portion of the sole under tension to expand both in the direction of tension and in a direction perpendicular to the plane of the sole. Thus, these apertures and polygonal features form an auxetic structure for outsole 120, which is described in further detail below.

As shown in FIG2 , outsole 120 includes a substantially flat surface including a plurality of apertures 131, also hereinafter referred to as apertures 131. As an example, an enlarged view of a first aperture 139 of apertures 131 is schematically shown in FIG2 . First aperture 139 is further described as having a first portion 141, a second portion 142, and a third portion 143. Each of these portions is connected together at a central portion 144. Similarly, in some embodiments, each of the remaining apertures in aperture 131 may include three portions connected together and extending outward from the central portion.

Typically, each of the plurality of orifices 131 can have any type of geometric structure. In some embodiments, the orifice can have a polygonal geometry, including convex and/or concave polygonal geometry. In this case, the orifice can be characterized by including a specific number of vertices and edges (or sides). In an exemplary embodiment, the orifice 131 can be characterized by having six edges and six vertices. For example, the orifice 139 is shown as having a first side 151, a second side 152, a third side 153, a fourth side 154, a fifth side 155, and a sixth side 156. In addition, the orifice 139 is shown as having a first vertex 161, a second vertex 162, a third vertex 163, a fourth vertex 164, a fifth vertex 165, and a sixth vertex 166.

In one embodiment, the shape of the orifice 139 (and correspondingly the shape of one or more of the orifices 131) can be characterized by a circular and equilateral regular polygon. In some embodiments, the geometry of the orifice 139 can be characterized by a triangle having sides that are not straight but have inwardly pointing vertices at the midpoints of the sides. The concave angles formed at these inwardly pointing vertices can range from 180° (when the sides are completely straight) to, for example, 120° or less.

Other geometric configurations are also possible, including various polygonal and/or curved geometric configurations. Exemplary polygonal shapes that can be used with one or more of the orifices 131 include, but are not limited to, regular polygonal shapes (e.g., triangles, rectangles, pentagons, hexagons, etc.) as well as irregular polygonal shapes or non-polygonal shapes. Other geometric configurations can be described as quadrilaterals, pentagons, hexagons, heptagons, octagons, or other polygonal shapes with concave sides.

In an exemplary embodiment, the vertices of an orifice (e.g., orifice 139) may correspond to an interior angle less than 180 degrees or an interior angle greater than 180 degrees. For example, for orifice 139, first vertex 161, third vertex 163, and fifth vertex 165 may correspond to an interior angle less than 180 degrees. In this specific example, each of first vertex 161, third vertex 163, and fifth vertex 165 has an interior angle A1 less than 180 degrees. In other words, orifice 139 may have a locally convex geometry at each of these vertices (relative to the outside of orifice 139). In contrast, second vertex 162, fourth vertex 164, and sixth vertex 166 may correspond to an interior angle greater than 180 degrees. In other words, orifice 139 may have a locally concave geometry at each of these vertices (relative to the outside of orifice 139). In this specific example, each of second vertex 162, fourth vertex 164, and sixth vertex 166 may correspond to an interior angle greater than 180 degrees.

While embodiments have been described with orifices having approximately polygonal geometries, including approximately point-like vertices at which adjacent sides or edges connect, in other embodiments, some or all of the orifices may be non-polygonal. Specifically, in some cases, the outer edges or sides of some or all of the orifices may not connect at vertices, but may instead be continuously curved. Furthermore, some embodiments may include orifices having geometries that include straight edges connected via vertices and curved or nonlinear edges that do not have any points or vertices.

In some embodiments, apertures 131 may be arranged in a regular pattern on outsole 120. In some embodiments, apertures 131 may be arranged so that each vertex of an aperture is positioned adjacent to the vertex of another aperture (e.g., an adjacent or nearby aperture). More specifically, in some cases, apertures 131 may be arranged so that each vertex with an interior angle less than 180 degrees is positioned adjacent to a vertex with an interior angle greater than 180 degrees. As an example, first vertex 161 of aperture 139 is positioned adjacent to or adjacent to vertex 191 of another aperture 190. Here, vertex 191 is seen to have an interior angle greater than 180 degrees, while first vertex 161 has an interior angle less than 180 degrees. Similarly, second vertex 162 of aperture 139 is positioned adjacent to or adjacent to vertex 193 of another aperture 192. Here, vertex 193 is seen to have an interior angle less than 180 degrees, while second vertex 162 has an interior angle greater than 180 degrees.

It can be seen that the configuration resulting from the above arrangement divides sole structure 120 into smaller geometric sections, the boundaries of which are defined by the edges of apertures 131. In some embodiments, these geometric sections can be composed of polygonal sections. For example, in an exemplary embodiment, apertures 131 are arranged in a manner that defines a plurality of polygonal sections 200, which are also referred to hereinafter as polygonal sections 200.

Typically, the geometry of the polygonal portion 200 can be defined by the geometry of the apertures 131 and the arrangement of the apertures 131 on the outsole 120. In an exemplary configuration, the apertures 131 are shaped and arranged to define a plurality of approximately triangular portions, wherein the boundaries are defined by the edges of adjacent apertures. Of course, in other embodiments, the polygonal portion can have any other shape, including a rectangle, a pentagon, a hexagon, and possibly other types of regular and irregular polygonal shapes. Furthermore, it will be understood that in other embodiments, the apertures can be arranged on the outsole to define a geometric portion that is not necessarily a polygon (e.g., consisting of edges of approximately straight lines connected at vertices). The shape of the geometric portion in other embodiments can vary and can include various circular, curved, wavy, undulating, non-linear, and any other types of shapes or shape features.

2, polygonal portions 200 can be arranged in a regular geometric pattern around each orifice. For example, orifice 139 is seen to be associated with a first polygonal portion 201, a second polygonal portion 202, a third polygonal portion 203, a fourth polygonal portion 204, a fifth polygonal portion 205, and a sixth polygonal portion 206. Furthermore, the approximately identical arrangement of these polygonal portions around orifice 139 forms an approximately hexagonal shape around orifice 139.

In some embodiments, different vertices of the orifice can function as hinges. Specifically, in some embodiments, adjacent portions of a material comprising one or more geometric portions (e.g., polygonal portions) can rotate about hinge portions associated with vertices of the orifice. As an example, each vertex of the orifice 139 is associated with a corresponding hinge portion that rotatably connects adjacent polygonal portions.

In an exemplary embodiment, the aperture 139 includes a hinge portion 210 (see FIG. 3 ) associated with the vertex 161. The hinge portion 210 is comprised of a relatively small portion of material connecting the first polygonal portion 201 and the sixth polygonal portion 206. As discussed in greater detail below, the first polygonal portion 201 and the sixth polygonal portion 206 can rotate relative to each other at the hinge portion 210. In a similar manner, each of the remaining vertices of the aperture 139 is associated with a similar hinge portion that rotatably connects the adjacent polygonal portions.

FIG3 illustrates a schematic sequence for the construction of a portion of outsole 120 under tension applied along a single axis or direction. Specifically, FIG3 is intended to illustrate how the geometric arrangement of apertures 131 and polygonal portion 200 provides outsole 120 with auxetic properties, thereby allowing the portion of outsole 120 to expand both in the direction of applied tension and in a direction perpendicular to the direction of applied tension.

3, portion 230 of outsole 200 extends through various intermediate configurations due to tension applied in a single linear direction (eg, longitudinal direction). Specifically, four intermediate configurations may be associated with increasing tension levels applied along a single direction.

Due to the specific geometry of the polygonal sections 200 and the attachment of the polygonal sections 200 via the hinge portion, this linear tension is converted into rotation of the adjacent polygonal sections 200. For example, the first polygonal section 201 and the sixth polygonal section 206 rotate at the hinge portion 210. All of the remaining polygonal sections 200 similarly rotate as the aperture 131 expands. As a result, the relative spacing between adjacent polygonal sections 200 increases. For example, as clearly seen in FIG3 , the relative spacing between the first polygonal section 201 and the sixth polygonal section 206 (and therefore the size of the first portion 141 of the aperture 131) increases with increasing tension.

Because the increase in relative spacing occurs in all directions (due to the symmetry of the initial geometric pattern of the apertures), this results in the expansion of portion 230 along a first direction and a second direction orthogonal to the first direction. For example, in an exemplary embodiment, in an initial or non-tensioned configuration (see FIG. 3 on the left), portion 230 initially has an initial dimension D1 along a first linear direction (e.g., longitudinal direction) and an initial dimension D2 along a second linear direction orthogonal to the first direction (e.g., transverse direction). In the fully expanded configuration (see FIG. 3 on the right), portion 230 has a dimension D3 that increases in the first direction and a dimension D4 that increases in the second direction. It is clear, therefore, that the expansion of portion 230 is not limited to expansion in the tension direction. Moreover, in some embodiments, the amount of expansion (e.g., the ratio of the final dimension to the initial dimension) can be approximately similar between the first and second directions. In other words, in some cases, portion 230 can expand by the same relative amount in both the longitudinal and transverse directions, for example. Conversely, some other types of structures and/or materials can contract in a direction orthogonal to the direction of the applied tension.

In the exemplary embodiments shown in the figures, auxetic structures, including shoe outsoles comprised of auxetic structures, can be tensioned in either the longitudinal or transverse directions. However, the arrangements discussed herein for auxetic structures comprised of orifices surrounded by geometric portions provide structures that can expand in either a first direction along which pressure is applied, as well as in a second direction orthogonal to the first direction. Furthermore, it should be understood that the directions of expansion, i.e., the first and second directions, can be generally tangential to the surface of the auxetic structure. In particular, the auxetic structures discussed herein generally do not expand in a perpendicular direction generally associated with the thickness of the auxetic structure.

FIG4 is a top view of the side of the outsole 320 that is not in contact with the ground. FIG5 is a bottom view of the outsole of FIG4 . FIG5 is therefore a view of the side of the outsole 320 that is in direct contact with the ground. The outsole 320 has a heel region 331, a midsole or instep region 332, and a forefoot region 333. In some embodiments, the outsole 320 may be comprised of an auxetic structure. As shown in these figures, the outsole 320 has a pattern of apertures 321 formed by a pattern of triangular portions 322 connected at each of their vertices 323 to the vertices of adjacent triangles. The combination of six triangles 322 surrounding each of the apertures 321 (depicted in FIG5 as blown open with dashed lines) forms a hexagonal pattern 324 (depicted in FIG5 with dashed dotted lines) as shown in FIG5 .

As shown in FIG5 , the hexagonal pattern varies in size and shape across the length and width of the outsole. For example, the size of the hexagonal pattern is greatest at the center 334 of the heel region 331 and smallest at the instep region 337. For example, the distance from one vertex of the aperture to the adjacent vertex of the aperture may be twice as great at the center of the heel region as at the instep region of the sole. At the heel, in an exemplary embodiment, the concave angles of the generally transversely oriented triangle sides are quite shallow, at approximately 150° to 170°, such as 160°, whereas at the forefoot, the concave angles are more acute, at approximately 110° to 130°, such as 120°. More typically, the concave angles may vary from 100° to 170°. Using this geometry, the auxetic structure at the heel expands in width to a greater extent when subjected to longitudinal tension than it expands in length when subjected to transverse tension. At the forefoot, the concave angles are not much different, so that the expansion in width when the forefoot is stretched longitudinally is not much greater than the expansion in length when the forefoot is stretched transversely.

In the examples shown in Figures 4 and 5, the geometric pattern forms through-hole apertures 321, so that the apertures 321 are distributed throughout the outsole 320 to form holes. However, in other embodiments, the outsole 320 need not include through-hole apertures. Instead, the outsole 320 may include blind holes, so that there is a thin, continuous layer of material at the top or bottom of the outsole. In still other embodiments, the geometric pattern may form through-holes in certain portions of the outsole and blind holes in other portions of the outsole.

FIG6 is an enlarged view of the heel region 331, midsole region 332, and forefoot region 333 of the outsole shown in FIG5, respectively, when the outsole is not pulled downward. FIG6 shows that the hexagonal pattern formed by the combination of articulated triangles forming apertures in the central portion 334 of the heel region 331 is larger than the hexagonal patterns toward the lateral side 335 or medial side 336 of the heel region 331. For example, the hexagonal pattern 351 arranged in the central portion 334 can be larger than the hexagonal pattern 353 arranged on the medial side 336 of the heel region 331. If the heel strikes the ground or playing surface perpendicular to the ground, the triangular portion 322 of the central portion 334 of the heel moves toward the center of the hexagonal pattern 351. This increases the density of the structure directly beneath the heel and helps to cushion the impact of the heel striking the ground.

In the embodiment shown in FIG6 , the hexagonal pattern in the central portion 334 of the heel can be approximately symmetrical about a longitudinal axis that bisects the apertures 321 at the center of the hexagonal pattern. For example, apertures 342 are approximately symmetrical about axis 390 that bisects apertures 342. However, the features of adjacent rows of apertures on either side of the central portion 334 of the heel are asymmetrical. For example, apertures 343 on the medial side of the heel have inwardly pointing portions 391 that are longer than outwardly pointing portions 392. The apertures 341 on the lateral side of the heel also have a similar geometry, with inwardly pointing portions that are longer than the outwardly pointing portions of apertures 341. This geometry maximizes the ability of the central region to compress and attenuate impact forces when the heel strikes the ground or playing surface. In some embodiments, the dimensions of the features on the lateral side 335 and medial side 336 of the heel are significantly smaller (e.g., two-thirds the size or less) than the dimensions of the features at the center of the heel. The smaller size of the hexagonal pattern on the lateral and medial sides of the heel allows the heel to maintain its curved shape around the upwardly curved profile of the heel and maximizes flexibility on the medial and lateral sides of the heel.

FIG7 is a cross-section taken at the heel portion 331 shown in FIG6 , illustrating an example of a footwear construction. In this example, the heel has three layers—an outsole 320, a midsole 340, and an insole 350. In some embodiments, the outsole 320 is made of a relatively hard, wear-resistant material, while the midsole 340 and insole 350 are made of a relatively resilient material to provide a comfortable article of footwear. FIG7 also illustrates an aperture 321 extending through the outsole 320 and midsole 340.

Figures 8-9 illustrate the auxetic characteristics of the heel region 331 of the outsole 320 when, for example, a wearer lands on the heel of the footwear. Under longitudinal tension, the heel region 331 increases in length. However, due to the structure of the outsole 320 as a pattern of hinged triangles connected at their vertices, the heel region 331 also increases in its lateral dimension (e.g., its width). For illustrative purposes, the initial size of the heel region 331 before the application of tension is represented by line 371. This can help improve traction between the heel and the playing surface for various reasons. For example, because the surface contacting the ground stretches across a slightly larger area, it increases the likelihood that at least a portion of the heel will contact a non-smooth playing surface upon heel strike. Additionally, the openings between the triangles allow the triangles to expand, thereby increasing the area of contact with the ground. Furthermore, the impact opens the inner edges of the triangles' star-shaped apertures, resulting in increased engagement of these edges with the playing surface.

FIG10 is another view of the heel area shown in FIG8 . In this example, heel area 331 has been subjected to lateral tension. As a result, the triangle has rotated and the size of heel area 331 has increased longitudinally, as well as laterally. Dashed line 373 illustrates the outline of heel area 331 when it is not under tension. This configuration provides a further improvement in traction when the wearer makes a sudden, sharp turn or moves to one side or the other.

FIG11 is a schematic diagram of a shoe sole showing an aperture 321 formed from a pattern of triangular portions 322 connected to one another at their vertices 323. In some embodiments, the aperture 321 may be characterized as a triangular star-shaped aperture due to the presence of three star-shaped arms extending from a central region. However, as previously discussed, the aperture 321 is not limited to a particular geometry and may have any polygonal or non-polygonal geometry in other embodiments.

As noted above, the joint at the apex acts as a hinge, allowing the triangular portions 322 to rotate relative to each other when the sole is under tension. Regions 901 and 902, represented by dashed circles, are identified in FIG11 for further discussion with respect to FIG12-14.

FIG12 is an enlarged view of the area designated 901 in FIG11 when the forefoot is laterally pulled. As shown in FIG12 , when the forefoot is laterally pulled, for example, when the wearer leaves to one side, the outsole at the forefoot increases in size longitudinally and also increases transversely, thereby improving the traction with the ground or playing surface. FIG13 is another enlarged view of the area designated 901 in FIG11 . In this example, the configuration of the sole when it is longitudinally pulled, for example, when the wearer leaves from his or her forefoot. FIG13 shows that when the forefoot is longitudinally pulled, the outsole increases its transverse dimension as well as its longitudinal dimension.

FIG14 is an enlarged view of the area designated 902 in FIG11 when the mid-shoe portion of the sole is under moderate longitudinal tension, e.g., when contact with the ground transitions from the heel to the forefoot. As shown in FIG14 , when the mid-shoe portion of the sole is under longitudinal tension, the mid-shoe portion increases in both its transverse and longitudinal dimensions. FIG15 illustrates the mid-shoe portion under even greater longitudinal tension, showing that the sole has increased in both transverse and longitudinal dimensions to an even greater extent.

FIG16 is an enlarged view of the forefoot region 333 when the forefoot is in a static condition and therefore not under tension. In the middle portion 381 of the forefoot region 333, the outsole has a larger hexagonal pattern 324 on the inside of the ball of the foot (i.e., where the phalanges from the big toe meet the metatarsal bones), where the wearer will leave the ball of the foot when suddenly moving to the side, and at the big toe, where the wearer will leave this position to jump or run forward. These larger features help absorb the impact of these movements and increase the traction of these areas of the outsole with the playing surface.

FIG17 illustrates the forefoot region of FIG16 when subjected to longitudinal tension, showing that the region under tension has increased in both its transverse dimension and its longitudinal dimension. FIG18 illustrates the forefoot region of FIG16 when subjected to transverse tension, showing that the region under tension has increased in both its longitudinal dimension and its transverse dimension. As can be seen in FIG17 and FIG18 , the auxetic structure of the outsole provides improved traction when subjected to either longitudinal or transverse tension because the overall surface area of the outsole increases under either tension.

Figures 19 to 25 illustrate embodiments with different sole structures. In this embodiment, the sole 400 is made of an auxetic structure that appears to have no openings when the structure is not in tension. However, when the structure is in tension, the structure exhibits hexagonal openings. Thus, the structure can be described as "closed" when it is not in tension (Figures 19 and 21), and "open" when it is in a longitudinal, transverse, or other tensioned state in the plane of the structure (Figure 22).

Figure 20 is a side cross-sectional view of sole 400, showing a ground contact pattern 410 on outsole 401 and midsole 402. In some embodiments, as seen in Figure 20, outsole 401 may also include an outer covering 403. The embodiment shown in Figures 19 to 25 has an outsole 401 made of a relatively hard material, such as hard rubber, and a midsole 402 made of a relatively resilient material, such as EVA foam or foam plastic, for example.

As shown in Figures 19, 21, 22, and 23, both the outsole 401 and the midsole 402 have auxetic structures as described above, i.e., they have a triangular pattern connected at their triangular vertices. The joints between the vertices 423 of the triangles 422 are flexible, so that the joints act as hinges, allowing the triangles to rotate relative to each other, thereby creating the apertures 421 shown in Figures 22 and 23.

The portion of the sole drawn in FIG19 by the black dashed line 440 is shown in the four schematic diagrams of FIG23. These diagrams show how the size of the sole increases from its initial value when the sole is in an untensioned state (the first diagram on the left), to when the sole is in a low tension state (the second diagram), then when the sole is in a moderate tension state (the third diagram), and finally when the sole is in a maximum tension state (the fourth diagram).

Figure 24 is a bottom view of the outsole of the embodiment shown in Figure 19 when it is not under tension. Figure 24 identifies triangular feature 450 and triangular feature 451 within black dashed line 440. Figure 25 is a sequence of four schematic diagrams illustrating how triangular feature 450 and triangular feature 451 rotate away from each other and open an aperture 453 therebetween as the outsole is subjected to increasing tension.

In the exemplary embodiment shown in Figures 19 to 25, the outsole has a tread pattern 410 that provides improved traction with the ground or playing surface. The outsole optionally also has a thin, elastic, and flexible "skin" or outer covering 403 that is molded to fit over the tread pattern. For example, the outer covering can be made of an elastic material. The outer covering can be used to prevent water, dirt, particles, or other debris from entering the triangular openings created when the sole is stretched.

The outer covering can be molded to fit into the star-shaped triangular openings in the auxetic structure of the outsole. For example, Figures 26-31 are schematic diagrams of an embodiment in which a resilient and flexible outer covering is molded to fit into the triangular star-shaped openings of the auxetic structure. Figure 26 shows the outsole structure 501 when not in tension. The outsole structure 501 has triangles 522 connected at their vertices 523 to adjacent triangles 522 separated by openings 521. When the sole structure is in tension in one direction, the sole structure increases in size in that direction and in a direction orthogonal to that direction and in the plane of the structure, as shown in Figure 27.

FIG28 is a schematic diagram of a top view of outer covering 503, i.e., the view from the inside of outer covering 503 as it would appear when attached to the outsole. This figure shows features 551 protruding from surface 550 of outer covering 503. FIG29 is a schematic diagram illustrating how outer covering 503 mates with outsole 501. Features 551 on outer covering 503 are now shown from the opposite side of outer covering 503, making features 551 appear as recesses rather than protrusions. The outer covering (which will be on the bottom of the article of footwear and therefore have a ground-contacting surface) exhibits a triangular ground contact pattern 552. Because outer covering 503 is made of a stretchable, elastic material, outer covering 503 easily stretches to accommodate increases in length and width regardless of the tension in the outsole 501 portion. The pattern of feature 551 thus serves the dual purpose of engaging the auxetic material of outsole 501 and providing a triangular tread pattern 552 that serves to enhance the wearer's traction against the playing surface.

FIG30 is a side perspective view of a portion of the outsole structure 500 and the outer covering 503, illustrating how the vertices in the outer covering 503 fit into the apertures 521. Because the outer covering 503 is made of a thin, flexible, and elastic material, it can easily stretch to accommodate the expansion of the outsole structure 501 when it is stretched longitudinally or laterally. FIG31 is a cross-section of a portion of an exemplary structure of the sole structure 500, illustrating the midsole 530 and the outsole layer 531, as well as the outer covering 503.

Figures 32-38 illustrate another embodiment of an article of footwear 600 having a sole with a lightweight, resilient, and comfortable auxetic structure. This article of footwear is suitable for use as a jogging or walking shoe. As shown in Figure 32, this embodiment has an open-woven upper 601, an outsole 602 composed of an auxetic structure, and an insole 603. Figure 32 shows that the polymer material forming the outsole 602 curves upward around the rear portion 631 of the heel 630 of the footwear, providing additional reinforcement, support, and protection at the rear portion of the heel. As shown in Figures 33 and 34, the outsole 602 has a pattern of concave triangular openings 621 formed by triangles 622, each connected at its vertex 623 to the vertex of another triangle. In this embodiment, the size of the concave triangular openings 621 is relatively uniform throughout the outsole 602. When a portion of the footwear 600 is placed in longitudinal or lateral tension due to impact with the ground, that portion of the outsole expands in both directions, thereby absorbing the shock and improving traction as described above. The outsole 602 can be made by molding the auxetic structure shown in Figures 33-35 into a synthetic rubber, polyurethane, or thermoplastic polyurethane material.

FIG35 is a schematic diagram of an enlarged view of the rear portion 631 of the heel 630 of the article of footwear 600. As shown in FIG35 , the rear portion 631 of the heel 630 of the upper 601 can be covered with an auxetic structure, which serves as the outsole 602, to reinforce the rear portion of the heel. This can be achieved by overmolding the fabric of the upper 601 with a polymer, allowing the polymer to penetrate and bond with the material of the upper 601. As shown in FIG35 , the auxetic structure has concave corners on the bottom side of the aperture, causing the auxetic structure to expand laterally when it is longitudinally stretched. This action helps pull the shoe onto the heel of the wearer's foot.

As best shown in FIG36 and also shown in FIG34, the flexibility of the footwear 600 is enhanced by a cutout 650 at the instep area 604 of the outsole 602. The cutout 650 restricts the outsole 602 to the outside of the footwear only at the instep area 604, thereby providing less resistance to the upward flexion of the heel relative to the forefoot. This structure provides a comfortable, low-stress article of footwear particularly suitable for activities such as jogging or walking.

FIG37 is a schematic diagram showing, in this embodiment, upper 601 being implanted in insole 660 via stitches 661. Outsole 602 can then be attached to the bottom of insole 650, for example, by using adhesive or other means, such as by fusing, molding, or stitching. FIG38 is a cross-section through a portion of the forefoot of article of footwear 600 as shown in FIG33 , showing insole 660, opening 621, outsole 602, and optional midsole 603.

39-43 are schematic diagrams of an article of footwear 700 that can be used, for example, as a running shoe for running on a hard surface, such as a paved road or indoor track, where the runner will pound the footwear against the ground. This embodiment has a woven fabric upper 701 and a molded hard rubber or polyurethane outsole 702.

As shown in Figure 40, outsole 702 has a pattern of a hexagonal pattern 720, which has a concave triangular opening 721 formed by triangles 722. Triangles 722 are connected at their apex 723 so that they act as hinges, thereby allowing triangles 722 to rotate relative to each other in response to longitudinal or lateral tension. When any part of the outsole contacts the ground or the playing surface, the vertical compression of the outsole pushes the triangle toward the center of the hexagonal pattern, i.e., the triangular star-shaped opening collapses toward its center. This increases the density of the outsole in the impact zone and weakens the impact force. The pattern in outsole 702 can be formed by molding the outsole material to form a pattern, or by cutting out a triangular star-shaped portion from a solid material.

In this embodiment, the hexagonal pattern is approximately the same size from the heel to the toe of the foot, with one hexagonal feature 741 directly under the wearer's heel and several hexagonal patterns 743 under the ball of the wearer's foot, as shown in Figure 40. As best shown in Figure 41, the outsole 702 also has a hexagonal feature 742 directly under the wearer's big toe. The hexagonal pattern 720 toward the inside, outside, front, or back of the sole 702 is bent upward from the outsole and attached to the fabric of the upper 701 by overmolding or by using an adhesive.

As shown in Figure 42, the rear portion 731 of the heel 730 of the upper 701 is reinforced using a secondary molded portion of hard rubber or polyurethane 750 that is otherwise attached. The secondary molded portion has a hexagonal feature with a concave triangular opening formed by triangles connected at its apex. When the footwear is pulled over the heel of the wearer's foot, the concave triangular opening expands laterally, allowing the footwear to slide more easily over the wearer's heel. Figures 39 and 42 show that the sole material portion can be molded on the fabric of the upper 701, thereby providing reinforcement and wear resistance to the lower edge of the upper 701.

Figure 43 is a schematic diagram of a cross-section of the forefoot portion of the embodiment of Figure 40, taken just in front of the shoe laces as shown in Figure 40. The figure shows the outsole 702 having apertures 721 attached to the elastic insole 703. The outsole 702 may be attached to the insole 703 using adhesives, overmolding, or any other suitable means.

Figure 44 is a schematic diagram of another embodiment of a shoe 800 that can be used for running or other sports or recreational activities. This shoe is roughly similar to the shoe shown in Figure 32, but this shoe has another peripheral band 810 that connects the sole 802 to the material of the upper 801. The peripheral band 810 extends around the entire perimeter of the sole 802 and the upper 801. Figure 45 is a schematic diagram of the interior view of the shoe 800 in its heel area 803, showing an insole 820 attached to the bottom edge of the peripheral band 810 using stitches 821. The upper edge of the peripheral band 810 is attached to the bottom edge of the upper 801. Other methods can also be used to attach the peripheral band 810 to the insole and the upper. The peripheral band 810 provides additional flexibility for footwear 800 by disengaging the upper 801 from the sole 802, thereby allowing the sole 802 to expand without being restricted by the upper 801. The pattern of apertures 830 in the midsole can be seen beneath the insole 820 .

The auxetic structures used for the outsoles and midsoles shown in these figures can be manufactured by molding conventional polymers (e.g., EVA, rubber, polyurethane, thermoplastic polyurethane) to have a pattern of connected triangles or polygons with triangular or polygonal openings as described above. The structures can also be manufactured by casting a solid polymer sheet and cutting the desired pattern into the sheet. For example, the auxetic structures shown in Figures 4-15 can be produced by molding a polymer to have the desired pattern, while the auxetic structures shown in Figures 16-19 can be produced by cutting the pattern into a polymer sheet.

In some of the sole structures described above, the entire sole is comprised of an auxetic structure. However, this is not required for all embodiments. For example, embodiments may utilize the auxetic structure described above in any one, two, or three of the heel, midsole, or forefoot regions of the sole, or throughout the sole. The sole may have a separate outsole layer. The sole may optionally have an outsole and an insole, or an outsole, midsole, and insole, or an outer covering, outsole, midsole, and insole, or any combination thereof. The sole may have even more layers, as long as the sole exhibits an auxetic structure such that, when tension is applied in one direction, the sole expands in a direction orthogonal to the direction of tension.

The above description has described auxetic structures using a hexagonal pattern formed by hinged triangles, with openings that increase in both length and width when tensioned longitudinally and in both width and length when tensioned transversely. These structures can also be formed using auxetic foam, which is a material with a negative Poisson's ratio, such that the resulting structure expands in a direction orthogonal to the applied tensile force due to its inherent properties and because the material itself is inherently auxetic.

This embodiment describes an auxetic structure having a large thickness compared to some other types of auxetic materials. In general, the thickness of an auxetic structure, such as an outsole incorporating the auxetic structure, can vary. In some embodiments, an auxetic structure forming part of a sole structure can have a thickness greater than or equal to one millimeter. In some embodiments, the auxetic structure can have a thickness greater than five millimeters. In some embodiments, the auxetic structure can have a thickness greater than ten millimeters. In still other embodiments, the auxetic structure can have a thickness greater than ten millimeters. Furthermore, the thickness of the auxetic structure can be selected to provide desired properties, such as cushioning and support.

In some embodiments, the thickness of the auxetic structure in the sole can be used to enhance the cushioning provided by the auxetic structure. Figures 46 and 47 illustrate how one or more apertures can change under an applied compressive force, which can generally be applied in a vertical direction. When the outsole is compressed, such as when the outsole strikes the ground, the triangles tend to collapse toward the center of their respective triangular apertures, thereby increasing material in the impact area and further cushioning the impact. On the other hand, when portions of the outsole are subjected to tension, such as when a wearer steps away from the toe of their shoe, portions of the outsole expand laterally as well as longitudinally, thereby providing increased traction.

As seen in Figure 46, when not applying compressive force, the orifice 920 (schematically shown) of the part of outsole 900 can be open initially. However, when applying compressive force, as shown in Figure 47, orifice 920 can be closed. This can usually occur because the triangular portion 922 around orifice 920 can tend to expand (due to conservation of mass) in size under compressive force. This causes orifice 920 to shrink inwardly, and this orifice 920 can have the opening size that reduces or can be closed completely (as in Figure 40). Especially, triangular portion 922 can be pushed towards the center of orifice 920.

Although various embodiments have been described, this description is intended to be illustrative rather than restrictive, and it will be apparent to those skilled in the art that many more embodiments and implementations are possible within the scope of the embodiments. Therefore, the embodiments are not to be limited, except in accordance with the appended claims and their equivalents. Furthermore, various modifications and changes may be made within the scope of the appended claims.

Claims (26)

1. A type of footwear, comprising: vamp; Sole structure; The sole structure includes an outsole and a sole interlayer, the sole structure having a first direction tangent to the outer surface of the outsole and a second direction orthogonal to the first direction, wherein the second direction is also tangent to the outer surface of the outsole; The sole structure also includes a plurality of openings extending from the outer surface of the outsole and passing through both the outsole and the sole interlayer, wherein the plurality of openings are arranged in a geometric pattern to provide tensile properties to the outsole such that tensioning the sole structure in the first direction causes the outsole to expand in both the first and second directions. 2. The footwear article of claim 1, wherein the sole interlayer has a sole interlayer geometry that mates with the geometry of the outsole. 3. The footwear article of claim 1, wherein the geometric pattern comprises a polygonal portion of the outsole surrounding the plurality of openings. 4. The footwear article of claim 3, wherein the polygonal portions are connected to each other by a joint, the joint serving as a hinge allowing the polygonal portions to rotate relative to each other. 5. The footwear article of claim 3, wherein the polygonal portion is a triangular portion. 6. The footwear article of claim 1, wherein the plurality of openings are closed when the sole structure is not under tension. 7. The footwear article of claim 6, wherein the plurality of openings are open when the sole structure is under tension. 8. The footwear article of claim 1, wherein at least one of the plurality of openings is open when the sole structure is not stretched and not subjected to vertical compression, and is closed when the sole structure is subjected to vertical compression. 9. The footwear article of claim 1, further comprising an external covering distributed throughout the outsole. 10. The footwear article of claim 1, wherein the sole structure has a ground pattern. 11. The footwear article of claim 1, wherein the geometric pattern is a hexagonal pattern. 12. The footwear article of claim 1, wherein the sole structure comprises a tensile foam material. 13. A footwear article comprising an upper and a sole structure, wherein the sole structure includes an outsole and a sole midsole, the sole structure being characterized by having: The polygonal portion surrounding the polygonal opening. The polygonal portions are hingedly connected to adjacent polygonal portions such that the plurality of polygonal portions rotate relative to each other when the sole structure is under tension, and the polygonal portions define a plurality of orifices therebetween, the plurality of orifices extending from the outer surface of the outsole and passing through both the outsole and the sole interlayer; The plurality of openings are arranged in a geometric pattern to provide tensile properties to the outsole, such that when a portion of the outsole is subjected to longitudinal tension, it expands in both the longitudinal and transverse directions, and when the portion of the outsole is subjected to transverse tension, it expands in both the transverse and longitudinal directions. 14. The footwear article of claim 13, wherein the sole interlayer has a structure that mates with the structure of the outsole. 15. The footwear article of claim 13, wherein the polygonal portion is a triangular portion. 16. The footwear article of claim 13, wherein the sole structure further comprises an external cover attached to the bottom surface of the outsole. 17. The footwear article of claim 13, wherein the polygonal opening has a center, and wherein when the sole structure is subjected to vertical compression, the polygonal portion is pushed toward the center of the polygonal opening. 18. The footwear article of claim 13, wherein the outsole is attached to the upper by means of secondary molding the outsole onto the upper. 19. A type of footwear, comprising: A sole structure, the sole structure comprising an outsole and a sole midsole; The sole structure includes a pattern of polygonal openings formed by triangular portions surrounding the polygonal openings and extending from the outer surface of the outsole and through both the outsole and the sole interlayer. The polygonal aperture has a center; The triangular portions are connected at their vertices, such that the vertices act as hinges, thereby allowing the triangular portions to rotate relative to each other; The outsole of the shoe is characterized by having a transverse direction, a longitudinal direction, and a vertical direction; When a portion of the outsole is subjected to lateral tension, it expands in both the lateral and longitudinal directions. When a portion of the outsole is subjected to longitudinal tension, it expands in both the longitudinal and transverse directions. When the outsole portion of the shoe is subjected to vertical compression, the triangular portion is pushed toward the center of the polygonal opening. 20. The footwear article of claim 19, wherein the footwear article has a heel area, and wherein the pattern of the polygonal perforations extends through the heel area. 21. The footwear article of claim 19, wherein the outsole has an inner side, an outer side, and a back area, and wherein the outsole includes a cut-off portion on the inner side of the back area. 22. The footwear article of claim 19, wherein the outsole has a heel area and a back area, and wherein the polygonal opening is significantly larger in the heel area than in the back area. 23. The footwear article of claim 22, wherein the outsole has a forefoot area, and wherein the polygonal opening is larger in the forefoot area than in the backfoot area. 24. The footwear article of claim 19, wherein the outsole has a heel area, and wherein the polygonal opening in the heel area is characterized by having a generally laterally oriented lateral concave edge, and wherein the generally laterally oriented lateral concave edge has a shallow concave angle. 25. The footwear article of claim 19, wherein the outsole has a forefoot area, and wherein the polygonal opening in the forefoot area is characterized by having a generally laterally oriented lateral concave edge, and wherein the generally laterally oriented lateral concave edge has a sharp concave angle. 26. The footwear article of claim 19, wherein the outsole has a heel area, and wherein the heel area has an outer side, a center side, and an inner side, and The polygonal openings on the outer side and the inner side of the heel area are significantly smaller than the polygonal opening at the center of the heel area.