ARTICLE OF FOOTWEAR WITH SIPES

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional patent application claims priority to co-pending U.S. provisional patent app. no. 63/724,131, filed on Nov. 22, 2024, and titled “Article of Footwear With Sipes,” co-pending U.S. provisional patent app. no. 63/724,113, filed on Nov. 22, 2024, and titled “Article of Footwear With Sipes, ” and co-pending U.S. provisional patent app. no. 63/724,147, filed on Nov. 22, 2024, and titled “Article of Footwear With Sipes.” The entire contents of the above-referenced applications are incorporated herein by reference.

BACKGROUND

The present examples relate generally to articles of footwear, and in particular to articles of footwear with siped sole structures.

Articles of footwear generally include two primary elements: an upper and a sole structure. The upper may be formed from a variety of materials that are unitary in construction, stitched or adhesively bonded together to form a void within the footwear for comfortably and securely receiving a foot. The sole structure is secured to a lower portion of the upper and is generally positioned between the foot and the ground. In many articles of footwear, including athletic footwear styles, the sole structure often incorporates a midsole and an outsole.

In some articles of footwear, the sole structure may include one or more sipes extending through the sole structure. The sipes may improve the grip of the sole structure with the ground and may also provide the sole structure with additional flexibility. Conventionally, the sipes are formed in the sole structure through molding processes, with a mechanical cutting mechanism (e.g., a saw blade, a rotary milling head, etc.) having a cutting width (known as a kerf width) or by a cutting mechanism that uses heat or energy (e.g., a hot blade or laser) to remove or melt material. In all circumstances, the resulting sipe has a measurable kerf width, or gap, in the material of the sole structure so that the two opposing sidewalls on either side of the sipe are offset and not in contact with each other. Even in situations where a gap between the sidewalls is desirable, these manufacturing limitations restrict the design and functionality of sipes formed by conventional methods.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is described in detail below with reference to these figures.

FIG. 1 illustrates a top perspective view of a first example of an article of footwear in accordance with the present disclosure.

FIG. 2 illustrates a bottom view of the article of footwear of FIG. 1.

FIG. 3 illustrates an enlarged side cross-sectional view of the sole structure of the article of footwear of FIG. 1.

FIGS. 4A and 4B illustrate the first sidewall and the second sidewall of the carved sipe of FIG. 3.

FIGS. 5, 5A and 5B illustrate a side front cross-sectional view of the sole structure of FIG. 2 along cut line 5-5 and select cross-sectional reviews of a sipe along cut lines 5A-5A and 5B-5B.

FIG. 6 illustrate front cross-sectional views of the sole structure of FIG. 2 along cut-line 6-6.

FIGS. 7A and 7B illustrate side and top views of a blade for use in manufacturing a sole structure in accordance with the present disclosure.

FIGS. 7C and 7D illustrates the positions of a blade and a sole structure prior to and during a cut being made in accordance with the present disclosure.

FIG. 8 illustrates an example of a path of a reciprocating blade cutting through a sole structure in accordance with the present disclosure.

FIG. 9A is a schematic plan view of a footwear component manufacturing system in a first configuration, in accordance with aspects hereof.

FIG. 9B is a schematic plan view of a footwear component manufacturing system in a second configuration, in accordance with aspects hereof.

FIGS. 10A-G illustrates different examples of sole structure sipe patterns in accordance with the present disclosure.

FIG. 11 is a flow chart of a method of manufacturing a sole structure in accordance with the present disclosure.

FIGS. 12A-C illustrates different examples of carved sipes in accordance with the present disclosure having different cross-sectional profiles.

DETAILED DESCRIPTION

The present disclosure relates to an article of footwear including a sole structure having one or more sipes that are formed by slicing into the sole structure with a reciprocating blade, which cuts the material of the sole structure without removing or melting any significantly measurable amount of material. The resulting cut creates no appreciable gap in the material (e.g., kerf width) between the opposite sides of the cut. Stated differently, the material of the sole structure is divided along the path of the cut but since no material is removed or melted by the cutting process itself the design of the sipe is not required to incorporate the kerf width in its design. Accordingly, the sipe may be designed and manufactured with greater design flexibility, e.g., a sipe may have sharp angles or vertexes that were previously unable to be manufactured in a practical way.

Conventionally, sipes have been formed in a sole structure in several ways. The first would be using conventional mechanical cutting tools, such as a saw blade, with teeth that remove material (also known as kerf) as part of the cutting process. The resulting cut forms a gap in the material, known as the kerf width. In a second way of forming a sipe, a cutting blade is heated to facilitate its ability to cut through the material of the sole structure. The heated blade softens, melts or vaporizes the sole structure material it contacts during the cutting action, which also creates a gap in the material along the path the blades through the sole structure. Similarly, sipes may be cut into the sole structure using a laser, with the energy of the laser vaporizing or melting the material along the cut. Sipes may also be formed during the molding process of the sole structure itself. However, in all of these conventional methods, a gap is formed between the resulting opposing sidewalls of the sipe.

In some examples, such a gap is desirable. However, even when a gap between the sidewalls of a sipe is preferred, the conventional methods of forming the sipes are limited to certain geometries or may not be easily used when the sole structure comprises multiple materials. For example, due to the kerf width inherent in using a cutting mechanism (mechanical and/or energy), sipes having sharp corners or vertices (e.g., within the interior of the sipe) may not be attainable. While molding a sipe directly into a sole structure may address some of these difficulties, it may not be possible or may be more difficult to do so for a sole structure comprising multiple materials through which the sipe must be formed. Furthermore, mold geometries may be limited in other ways, such as needing to avoid forming mold undercuts that prevent a molded part's ejection from a mold.

In the present disclosure, sipes are cut into a sole structure using a reciprocating blade with a slicing edge and tip. Instead of using heat (e.g., heated blade or laser) or cutting teeth to facilitate the cutting action, the blade is mounted on a reciprocating mechanism (e.g., a reciprocating piston). The reciprocating action, as further described below, facilitates cutting through one or more layers of material of the sole structure but without removing or melting the material the blade comes into contact with. A sipe formed by one pass of the blade through the sole structure will have opposing sidewalls that, instead of having a permanent gap between them, will remain adjacent to and in contact with each other when the sole is in a relaxed and un-flexed state.

In a typical sole structure comprising a midsole and an outsole with a ground-facing surface, a cut formed by one pass of the blade through the sole structure will have opposing sidewalls that, instead of having a permanent gap between them, will remain adjacent to and in contact with each other when the sole is in a relaxed and un-flexed state. A second cut that at least partially intersects the first cut along an interior edge will allow the portion between the cuts (the carved portion) to be removed, forming a carved sipe with a first sidewall, an opposing second sidewall, and a cavity defined by the two sidewalls and the plane formed by the ground-facing surface. Each of the opposing sidewalls with have an outsole portion and a midsole portion, with both portions being co-planar with each other. In other examples, the sipes may be formed in a sole structure that is a single layer (e.g., only an outsole or a midsole) or more than two layers (e.g., an outsole, a first midsole layer and a second midsole layer). The ability to form cuts into the sole structure without inherently creating an undesired gap allows for greater freedom in designing sipes to have different geometries and configurations.

The reciprocating cutting action used to form sipes in accordance with the present disclosure may leave, in examples, characteristic striations across the faces of the sidewalls formed on either side of the sipe. It is noted that in other examples, however, the cutting action of the blade may not leave visible striations on the face of one or more sidewalls or portions of a sidewall.

A sole structure with sipes in accordance with the present disclosure, as further discussed herein, may provide several benefits and advantages over conventionally formed sipes. In addition to being able to manufacture sole structures having sipes with more complex geometries, an article of footwear manufactured with sipes in accordance with the present disclosure may also be more sustainable and durable.

Turning now to FIG. 1, an example article of footwear (hereinafter referred to as article 100) in accordance with the present disclosure is provided. In the examples described herein, the article 100 has the form of a general purpose athletic shoe. However, in other examples, the article 100 may be another type of athletic footwear including, but not limited to, basketball shoes, hiking boots, soccer shoes, football shoes, sneakers, running shoes, cross-training shoes, rugby shoes, baseball shoes as well as other kinds of shoes. Moreover, in examples, the present disclosure is contemplated to be applicable to various other kinds of non-sports-related footwear, including, but not limited to, slippers, rain boots, sandals, high-heeled footwear, and loafers.

For consistency and convenience, directional adjectives are employed throughout this detailed description corresponding to the illustrated examples. The term “longitudinal” as used throughout this detailed description and in the claims refers to a direction oriented along a length of a component (e.g., an upper or sole component). In some cases, a longitudinal direction may be parallel to a longitudinal axis that extends between a forefoot portion and a heel portion of the component. The term “transverse” as used throughout this detailed description and in the claims refers to a direction oriented along a width of a component. In some cases, a transverse direction may be parallel to a transverse axis that extends between a medial side and a lateral side of a component. Furthermore, the term “vertical” as used throughout this detailed description and in the claims refers to a direction generally perpendicular to a transverse and longitudinal direction. For example, in cases where an article is planted flat on a ground surface, a vertical direction may extend from the ground surface upward. Additionally, the term “inner” refers to a portion of an article disposed closer to an interior of an article, or closer to a foot when the article is worn. Likewise, the term “outer” refers to a portion of an article disposed further from the interior of the article or from the foot. Thus, for example, the inner surface of a component is disposed closer to an interior of the article than the outer surface of the component. The terms “heelward” refers to being in the direction of or being closer towards the heel of the article, and the term “toeward” refers to being in the direction of or being closer towards the toe of the article. This detailed description makes use of these directional adjectives in describing an article and various components of the article, including an upper and a sole structure.

Article 100 may be characterized by a number of different regions or portions. For example, the article 100 of FIG. 1 may be divided into a forefoot region 10, midfoot region 12, and heel region 14. In addition, article 100 may include lateral side 16 and medial side 18 on opposing sides of article 100. It is to be understood that these regions are not intended to demarcate precise areas of article 100. Rather, forefoot region 10, midfoot region 12, heel region 14, lateral side 16, and medial side 18 are intended to represent general areas of article 100 that provide a frame of reference during the following discussion.

Article 100 may comprise an upper 102 and a sole structure 104. Generally, the upper 102 may be any type of upper and can be secured to the sole structure 104 by adhesives, bonding, mechanical fasteners, or via a strobel. The upper 102 may be formed from a variety of different manufacturing techniques, resulting in various kinds of upper structures. For example, in examples, an upper could have a braided construction, a knitted (e.g., warp-knitted or weft-knitted) construction, or some other woven or nonwoven construction. The upper 102 may be formed from a variety of materials, such as organic or synthetic materials in the form of textiles, yarns, fibers, sheets, films, and the like. The upper 102 may be formed as a unitary construction or as a plurality of components joined together to form the upper 102.

The sole structure 104 of FIG. 1 comprises an outsole 110 and a midsole 120. The inner surface 114 of the outsole 110 and the ground-facing surface 122 of the midsole 120 are adjacent to each other along an interface 125. The outsole 110 and the midsole 120 may be attached to each other along the interface 125 via adhesives, heat bonding, co-molding, vulcanization, or other methods. It is understood that the sole structure 104, in an example, may omit one of the outsole 110 or the midsole 120. Similarly, it is contemplated that the outsole 110 and midsole 120 are substantially monolithic in structure and/or composition.

The outsole 110 may include a ground-facing surface 112 configured to provide traction for article 100 and also provide a durable, wear-resistant component for attenuating ground reaction forces and absorbing energy as article 100 impacts the ground. The outsole 110 may be manufactured from a variety of different materials, which may include, but are not limited to, rubber (e.g., carbon rubber or blown rubber), polymers, thermoplastics (e.g., thermoplastic polyurethane), as well as possibly other materials.

In examples, the outsole 110 may extend from forefoot region 10 through midfoot region 12 and to heel region 14, and from the lateral side 16 to the medial side 18. Stated differently, the outsole 110 and its ground-facing surface 112 may extend substantially across the entire surface area defined by the outer perimeter 106 of the sole structure. In other examples, the outsole 110 and its ground-facing surface 112 may only cover a portion or portions of the surface area defined by the outer perimeter 106 of the sole structure 104, exposing the ground-facing surface 122 of the midsole 120. The ground-facing surface 112 of the outsole 110 may be generally smooth, or may include features that enhance grip with the ground, such as treads formed as ridges, hemispheric protrusions, cylindrical or other geometric protrusions as well as other kinds of tread elements. The ground-facing surface 112 may be curved in the longitudinal direction, in the transverse direction, or in both. In other examples the ground-facing surface 112 may generally be flat. In examples, the outsole 110 has an outsole thickness 116 that is generally consistent. In other examples, the outsole thickness 116 may vary. For instance, the thickness may be a first thickness in the forefoot region 10 and a second thickness near the heel region 14 that is greater than the first thickness.

Midsole 120 may comprise a resilient material to attenuate ground reactions forces, absorbing and redirecting energy during walking, running, jumping or other movements and activities. In examples, the midsole 120 may extend from forefoot region 10 through midfoot region 12 and to heel region 14. In examples, the midsole 120 may be a continuous, one-piece component that extends from forefoot region 10 to heel region 14. In other examples, the midsole 120 may include multiple pieces or may include a gap or space in any of the regions. That is, in examples, the midsole 120 may be separated into two or more pieces.

In different examples, the midsole 120 may generally incorporate various provisions associated with midsoles. In examples, a midsole 120 may be formed from a polymer foam material that attenuates ground reaction forces (i.e., provides cushioning) during walking, running, and other ambulatory activities. In various examples, midsole 120 may also include one or more fluid-filled chambers, plates, moderators, or other elements that further attenuate forces, enhance stability, or influence the motions of the foot, for example. The midsole 120 may generally be manufactured from polyurethane, polyurethane foam, other kinds of foams as well as possibly other materials. In examples, the midsole 120 may utilize polymer foams, including but not limited to ethylvinylacetate (EVA), thermoplastic polyurethane (TPU) or polyurethane foams.

It may be desirable, for at least some applications, that the Shore A hardness of the outsole material be larger than the Shore A hardness of the midsole material, e.g., by at least about 20% and larger than the Shore A hardness of the insole material by at least about 50%. As a non-limiting example, the midsole material may include a polymer foam material, such as TPU foam or EVA, having a material hardness in the range of about 40 to about 60 Shore A (e.g., about 65 to about 80 Asker C). Conversely, the outsole material may include an elastic polymer material, such as polyvinylchloride (PVC), hard-compound polyurethane (PU), or a polycaprolactone (PCL) or polyester-based TPU, having a material hardness of about 75 to about 90 Shore A.

The densities of the materials forming the outsole 110 and the midsole 120 also may differ from each other. For instance, the outsole 110 may have a higher density than a midsole 120, thereby allowing for increased durability and wear resistance. In other examples, however, the density of the outsole 110 could be equal to the density of the midsole 120, or could be less than the density of the midsole 120.

Turning to the bottom view of the sole structure 104 in FIG. 2, the sole structure 104 includes a plurality of sipes that extend along the ground-facing surface 112. As used herein, the term “sipe” may refer to a slit, cut, or groove. A “carved sipe” is formed by multiple converging cuts to define opposing sidewalls and removing the intervening material between the sidewalls, which then defines a sipe cavity between them. The sole structure 104 of FIG. 2 comprises four carved sipes 400 that extend in a general longitudinal direction. The carved sipes 400 may be of different lengths, and may be generally straight or slightly curved. For example, the sole structure of FIG. 2 has two outer carved sipes 410 and two inner carved sipes 420, with the inner carved sipes 420 having a greater length in the longitudinal direction than the outer carved sipes 410. The carved sipes 400 are generally parallel to each other and do not intersect, but in other examples, as further described below, the sole structure 104 may have sipes (including carved sipes) that are angled with respect to each other, and may also include sipes that intersect with each other.

Each carved sipe 400 comprises a first sidewall and a second sidewall defining a cavity between them and the plane formed by the ground-facing surface 112. For example, a first carved sipe 421 comprises a first sidewall 150 and a second sidewall 160 defining cavity 429. The first sidewall 150 and the second sidewall 160 converge along an interior edge 170. The first carved sipe 421 has a first outsole edge 426 (also referred to generally as an outer edge herein) at the intersection of the first sidewall 150 with the ground-facing surface 112 of the outsole 110. Similarly, the first carved sipe 421 has a second outsole edge 428 at the intersection of the second sidewall 160 with the ground-facing surface 112. The first outsole edge 426 and the second outsole edge 428 meet at a first end 422 and a second end 424 of the first carved sipe 421, with the first end 422 located in the forefoot region 10 and the second end 424 in the midfoot region 12. In the sole structure of FIG. 2, each of the carved sipes 400 has both ends within the outer perimeter 106 of the sole structure 104. In other examples, a carved sipe may have one or both ends extending through the outer perimeter 106. The first and second sidewalls of the carved sipes 400 in FIG. 2 are gently curved as the carved sipe 400 narrows towards its ends and widens towards its middle. However, carved sipes 400 may be formed with many other different profiles. For instance, it is contemplated that carved sipes may comprise sidewalls with straight sections, or sections that are strongly curved or undulating. A carved sipe may also incorporate one or more sharp bends or angles (e.g., greater than 30 degrees) along its length.

The carved sipes 400 extend through the entire thickness 116 of the outsole 110 and into the midsole 120. In an alternative example the carved sipes 400 extend through only a portion of the outsole thickness 116 and do not extend into the midsole 120.

Turning to FIG. 3, which shows a cross section of the first carved sipe 421, the first sidewall 150 is angled with respect to the ground-facing surface 112 at a first sidewall angle 158. The first sidewall 150 comprises an exposed first face 151 that extends from the first outsole edge 426 to the interior edge 170, and an overcut portion 157 that extends into the foam of the midsole 120 past the interior edge 170 and ends at a first midsole edge 156 (depicted as a dot in FIG. 3; also referred to generally as an internal edge in some examples herein). Stated differently, the first outsole edge 426 is on a first side of a plane P-P defined by the second sidewall 160 and the first midsole edge is on a second side of the plane P-P. As discussed further below, the overcut portion 157 is created by an overcut to account for differences in how the materials of the sole structure 104 (e.g., the foam of the midsole 120) react to the motions of the reciprocating blade when the sole structure 104 has been previously cut. However, because it does not have a kerf width, the overcut does not create a permanent gap in the sole structure, which might otherwise cause the material of the sole structure 104 (e.g., the foam of the midsole 120) on either side of such a gap to collapse against itself in reaction to the forces experienced when the wearer stands, walks, runs or jumps.

The first face 151 of the first sidewall 150 includes an outsole portion 152 and a midsole portion 153. The outsole portion 152 and the midsole portion 153 are adjacent each other along the interface 125 of the outsole 110 and the midsole 120. As see in FIG. 3, the outsole portion 152 and the midsole portion 153 are coplanar with each other - that is, the first face 151 does not change orientation between the outsole portion 152 and the midsole portion 153. Similarly, the second sidewall 160 is angled with respect to the ground-facing surface 112 at a second sidewall angle 168 and comprises a second outsole portion 162 and a second midsole portion 163 that are co-planar with each other. In some examples, the first sidewall angle 158 and the second sidewall angle 168 are equal to each other at corresponding points along the first carved sipe 421. In other examples, the first sidewall angle 158 and the second sidewall angle 168 may be different along either a portion or the entirety of the sipe. Each of the first sidewall angle 158 and the second sidewall angle 168 may change along the length of the first carved sipe 421. The first carved sipe 421 may have a depth 145 measured from the plane of the ground-facing surface 112 to the interior edge 170 and a width 147 measured from the first outsole edge 426 to the second outsole edge 428. furthermore, a first distance between the first face 151 and the second face 161 at the ground-facing surface 112 of the outsole 110 (corresponding to width 147) is greater than a second distance between the first face 151 and the second face 161 at the inner surface 114 of the outsole 110.

Turning to FIG. 4A, which provides a frontal view of the first sidewall 150, a first plurality of striations 154 may be seen extending across the first face 151, with at least some of the striations 154 traversing through the interface 125 between the outsole portion 152 and the midsole portion 153 without a change in orientation. As further discussed below, the striations 154 may be created by the reciprocating cutting action of a reciprocating blade forming the first sidewall 150, which also creates an irregular profile for the first midsole edge 156 at the top of the first sidewall 150. It is noted that in other examples, however, the cutting action of the blade may not leave visible striations on the face of one or more sidewalls or portions of a sidewall. The first face 151 may also have a line of perforations 159 that are formed when the reciprocating blade cuts into the sole structure 104 to form the second sidewall 160.

Similarly, FIG. 4B, which provides a frontal view of the second sidewall 160, shows a second face 161 with a second plurality of striations 164 that do not change orientation as they traverse the interface 125 between the second outsole portion 162 and the second midsole portion 163. Because the second sidewall 160 has been formed by a different cutting pass, the first plurality of striations 154 and the second plurality of striations 164 may not match each other. A slit 167 is formed along the second sidewall 160 at the interior edge 170, which corresponds to the overcut portion 157 of the first sidewall. Because the overcut portion 157 of the first sidewall 150 is formed by a reciprocating blade that does not remove kerf or melt the midsole material, the slit 167 does not create a gap in the material of the sole structure 104 when the sole structure 104 is in a relaxed, un-flexed state, other than occurs by a release of internal tension of the material as a result of the slit. A second midsole edge 166, formed by the tip of the reciprocating cutting blade, generally aligns with the slit 167 (which defines the interior edge 170 of the first carved sipe 421) but includes uncut areas 169 where the second midsole edge 166 does not reach or extend past the slit 167. As a result, the foam of the second sidewall 160 may be torn in these uncut areas 169 when the carved-out portion of the sipe between the first sidewall 150 and the second sidewall is removed in order to fully remove the carved-out portion of the sole structure 104 from the first carved sipe 421. The uncut areas 169 may thus comprise a plurality of non-uniform surfaces on the second face 161.

Turning to the cross-sectional view of the first carved sipe 421 of FIG. 5 and enlarged cross-sectional views 5A and 5B, it can be seen that a depth 145 of a particular carved sipe may be consistent along its length while the width of the sipe may increase from width 147 to a second width 148 at different locations. As seen in FIGS. 5A and 5B, this may be accomplished by angling the first sidewall 150 and second sidewall 160 may be angled more steeply or less steeply. For example, angle 180 of the first sidewall in FIG. 5A is less steep than angle 182 in FIG. 5B. As also seen in FIG. 5A, a convergence angle 199 at which the first sidewall and the second sidewall converge (the convergence angle) may be very acute, without a radius of curvature. In examples, the angle is less than 10 degrees, or less than 20 degrees, or less than 30 degrees. As previously noted, such acute angles are not achievable by conventional sipe cutting methods.

In other examples, the first and second sidewalls may be cut at different angles with respect to the ground-facing surface in order to vary the depth and width of the sipe at different locations along its length. For example, a carved sipe may be created by cutting a first sidewall into the sole structure at a fixed angle relative to the ground-facing surface, and then cutting a second sidewall at a second fixed angle. The resulting sipe will have a fixed correlation between its depth and its width at any given location along its length. Such a sipe may therefore have a first end or a second end with zero depth and width - that is, it starts or ends at a point on the ground-facing surface of the outsole, and thus at least a portion of such a sipe may be formed only in the outsole of the sole structure. In other examples, such as when a sipe at a first location and a second location has the same width, a steeper angle of the sidewalls at the second location will result in a deeper sipe, with the sidewalls correspondingly having a greater length in the vertical direction. Furthermore, it is to be appreciated that if the two sidewalls are angled at different angles to the ground-facing surface, the sidewall with the shallower angle will have a greater length from the ground-facing surface to the shared interior edge. The depth of each sipe may be similar to one or more other sipes in the sole structure 104 or they may differ from each other.

The carved sipes 400 may improve the traction of the ground-facing surface 122 of the outsole against wet surfaces. Furthermore, regions of the sole structure 104 that have one or more carved sipes 400 may more readily react to forces applied to the sole structure by a wearer's foot. Turning back to FIG. 5 and also with reference to FIG. 6, the midsole 120 in regions with carved sipes 400 may comprise a connecting portion 210 and a siped portion 220. The connecting portion 210 may have a lower surface 212 and an upper surface 214, which may comprise the top surface of the sole structure 104 that is positioned adjacent to upper 102.

It is to be understood that the lower surface 212 of the connecting portion 210 is being used for descriptive purposes and not necessarily to indicate that connecting portion 210 and siped portion 220 are separate pieces; as seen in FIG. 5, the siped portion 220 and the connecting portion 210 of the midsole 120 may be formed from a single piece of material. In examples, the lower surface 212 may be a plane defined by the interior edges 170 of the carved sipes 400. In examples, the thickness of the connecting portion 210 and the siped portion 220 may be consistent or may vary along the length of sole structure 104. Furthermore, in some examples the siped portion 220 may comprise only a portion of the entire sole structure 104. For example, as seen in FIG. 5, there are no sipes, and therefore no siped portion, in the heel region 14 of sole structure 104.

The thickness of the connecting portion 210 may affect the flexibility of sole structure 104. In general, areas where the connecting portion 210 is larger or thicker in a vertical direction, the sole structure 104 may have decreased flexibility relative to other portions of the sole structure where the connecting portion is smaller or thinner in the vertical direction. In other examples, the flexibility in a particular region of the sole structure may also be influenced by whether a sipe extends fully through the sole structure (e.g., from the medial to the lateral edge), or if one or both ends of the sipe do not extend all of the way to the perimeter of the sole. Further still, instead of a single sipe, two shorter unconnected sipes may be aligned, so that the sole structure remains connected in several locations to provide increased stiffness in desired locations.

For example, as seen in FIG. 6 and also with reference back to FIG. 2, the carved sipes 400, together with the outer perimeter 106 of the sole structure 104, may define the siped portion 220 of the midsole 120 and the outsole 110 into a plurality of sole elements 230. The sole elements 230 are each connected to the connecting portion 210 of the midsole. Furthermore, as seen in FIG. 2, because each of the carved sipes 400 does not reach the outer perimeter 106, the sole elements 230 are each at least partially connected with each other by other parts of the midsole 120 and outsole 110. However, in other examples (further described herein), the sole elements 230 may be disconnected from each other within the siped portion 220 but connected via the connecting portion 210.

Turning back to FIG. 6, in the regions of the sole structure 104 with the carved sipes 400, the carved sipes 400 between the sole elements 230 may reduce the rigidity of the sole structure in the medial-lateral direction so that the curved ground-facing surface 112 of the sole structure 104 more readily flattens when a user steps onto the ground (e.g., the outsole elements 118 and 119 touching the ground). It is further contemplated that because the carved sipes also remove material from the outsole and midsole that would otherwise provide general resistance in all directions, the carved sipes 400, even if generally oriented in the longitudinal direction, may also increase the sole structure's flexibility in response to forces in the longitudinal, transverse, vertical and torsional directions, or a combination of any of the foregoing.

The sipes of the present disclosure may be formed by a reciprocating blade slicing through the sole structure 104. Turning to FIGS. 7A and 7B, an example of a blade 700 suitable for use in accordance with the present disclosure is shown. The blade 700 may have a straight plain cutting edge 702 ending in blade tip 704, and a spine 710 opposite the cutting edge 702. As used herein, a “plain cutting edge” means a cutting edge without distinct serrations or teeth. The cutting edge 702 may be double beveled or single beveled. The blade 700 may have a cutting edge length 712 and the cutting edge 702 may be angled at a cutting edge angle 716. In examples, the cutting edge length 712 may be between 20 and 100 mm and the cutting edge angle 716 may be between 70 and 85 degrees. The blade 700 may include a tip edge 706 that is straight with a blade tip length 715 and angled at a blade tip angle 718 from the blade tip 704. In examples, the blade tip angle 718 may be between 0 and 10 degrees. The blade 700 may have an overall length 714 measured from the blade tip 704 to a base 708. In examples, the overall length of the blade 7000 may be between 30 and 100 mm. The blade 700 may taper to from a base thickness 719 to a tip thickness 717 (i.e., the thickness of the blade at the start of the bevel edges of the tip edge 706). In examples the blade may have a base thickness 719 may be between 0.5 to 1.5 mm, and the tip thickness may be between 0.3 and 0.7 mm. While the blade 700 of FIGS. 7A-B has been described with specificity, it is contemplated that blades of other shapes and dimensions may also be suitable for use in accordance with the present disclosure.

In examples, the blade 700 is mounted to a reciprocating mechanism 701 (see, e.g., FIG. 7C), such as a piston, which may reciprocate at a frequency of between 140 and 200 hertz, or between 155 and 185 hertz, or about 170 hertz. In examples, the reciprocating mechanism 701 (and therefore the blade 700) reciprocates across a linear distance (hereinafter the reciprocating length RL), which, in examples, may be between 2 mm and 10 mm, or between 3 mm and 7 mm. The reciprocating length RL should be equal to or less than the cutting edge length 712 of the blade 700. Generally, the depth that the reciprocating blade 700 can cut into a sole structure is not dictated by the reciprocating length RL but by the cutting edge length 712. In examples, the reciprocating mechanism 701 may be pneumatically powered or electrically powered. In examples, the reciprocating motion of the blade relative to the reciprocating mechanism is linear only, but in other examples a more complex blade path (e.g., elliptical or oscillating) may be utilized.

The blade 700, driven by the reciprocating mechanism 701, is able to slice through the materials comprising the sole structure 104 (e.g., the outsole 110 and the midsole 120) without removing, destroying or melting as would happen with conventional manufacturing methods (saw, heated blade or laser).

In examples, as shown in FIG. 7C, to create a cut in the sole structure 104, the blade 700 may first be aligned to the ground-facing surface 112 of the sole structure 104 prior to cutting at the desired angle for the cut. While FIG. 7C shows the blade oriented to form a generally perpendicular cut, angled cuts are contemplated to be within the scope of the present disclosure. Initially, the material of the outsole 110, being selected for its durability and resistance to cutting or tearing, may resist being cut by the blade tip 704 or tip edge 706. Since the sole structure 104 may typically also comprise material (e.g., the foam of the midsole 120) that is intended to absorb impact, the sole structure 104 may least partially flex away or conform from the blade 700 instead of being cut through until the blade is brought close enough to the sole structure 104 so that the force applied at the blade tip 704, tip edge 706 or cutting edge 702 is sufficient to overcome the resistance of the outsole 110 to allow the blade to cut through the intended outsole thickness 116 completely. Put another way, as illustrated in FIG. 7D, the reciprocating blade 700 may initially contact and partially, but not completely, cut through the outsole 110 into the midsole 120, with the sole structure 104 instead deforming or deflecting in reaction to the reciprocating motion of the blade 700 (e.g., the a section of the midsole may be compressed so that a first length 790 measured from a fixed point in the midsole 120 to the ground-facing surface 112 is shortened to a second length 792, moving outsole 110 from its relative position in FIG. 7C (shown as 110A) until the sole structure 104 and blade 700 are brought close enough together so that blade 700 is able to puncture completely through the outsole thickness 116, with at least part of the sole structure 104 (such as the foam of the midsole 120) possibly being in a compressed state at the moment that the blade fully punctures the outsole 110. Once the outsole 110 is punctured, the sole structure 104, including the compressed foam of the midsole 120, may spring back from its compressed state, which may deepen the depth of the cut being made by the blade 700. The blade 700 can then be guided through the sole structure 104 so that the cutting edge 702 creates a cut through the sole structure 104 with the with the desired length, depth and profile, with the sole structure 104 on either side of the cut forming sidewalls with faces that are parallel to each other. In examples, the blade 700 may be moved relative to the sole structure so that it cuts through the sole structure material at a rate of between 1 to 30 mm/second when the blade 700 is cutting at a depth about 1 mm to about 10 mm. When the sole structure 104 comprises multiple layers, (e.g., the outsole 110 and midsole 120 of article 100), the portions of the sidewall face formed from the different layers will be coplanar with each other, even when the blade is angled relative to the exterior surface where the blade is entering into the sole structure. Depending upon the characteristics of the blade 700 and the sole structure 104, additional flexing of the sole structure 104 in response to the reciprocating motion of the blade 700 may also occur during the cutting action.

While FIGS. 7C and 7D show the blade being introduced into the sole structure at a generally perpendicular angle, to form a carved sipe the blade may instead be introduced at an angle. Each of the carved sipes 400 described herein, such as first carved sipe 421 in FIG. 2, may be formed by two or more separate cuts made by the reciprocating blade 700. The sole structure 104 may be first introduced at a first angle into the blade 700 corresponding to the desired first sidewall angle 158 of the first sidewall 150, and then maneuvered so that the profile of the first sidewall 150 is formed. The blade 700 may enter the ground-facing surface 112 at the first end of the sipe and exits at the second end of the sipe, or vice versa. The sole structure 104 is then reintroduced to the blade 700 at a second angle corresponding to the second sidewall angle 168 of the second sidewall 160. For the second cut, the blade 700 may enter the ground-facing surface 112 at the same end as the first cut entered or at the other end. In other examples, the blade may enter the ground-facing surface corresponding to different points along the first outsole edge or second outsole edge, in which case multiple cuts may need to be performed to fully form a sidewall of the carved sipe. Such a cutting process may be desirable for sipe where the ends of the sipe may have sidewalls with relatively shallow angles, which may increase the difficultly that the blade may have in initially puncturing through the material of the outsole 110, and thus making it preferable to start a cut by introducing the blade into the sole structure 104 at a steeper angle at a different point along the length of the sipe.

As described above, the reciprocating motion of the blade and the sole structure's reaction during the cutting process may create striations along the faces of the material being cut (e.g., the first plurality of striations 154 on the outsole portion 152 and midsole portion 153 of the first face 151). At least some of the striations will cross the interface 125 of the outsole and the midsole without a change in orientation. When the sipe comprises a single continuous incision, both sidewall faces (e.g., first face 151 and second face 161) may have matching striations formed from the reciprocating motion of the blade 700 while the sole structure is advanced. It is noted that in other examples, however, the cutting action of the blade may not leave visible striations on the face of one or more sidewalls or portions of a sidewall.

Furthermore, depending upon the frequency of reciprocation, the profile of the cutting edge and tip, and the speed at which the blade is progressed through the sole structure, the midsole edges formed by the blade cutting though the material of the sole structure 104 may have a non-linear profile. In examples, a midsole edge may have a profile at least partially corresponding to an oscillating path that the blade tip 704 and tip edge 706 take through the sole structure material. As shown in FIG. 8, the combination of the reciprocation of the blade 700 and the motion of the sole structure 104 relative to the blade 700 during the cutting process results in the blade tip 704 taking an oscillating path 750 through the material of the sole structure 104. However, as discussed previously, the material of the sole structure 104 may also intermittently resist being cut until the pressure at the cutting edge or tip is sufficient to overcome the resistance. This phenomenon of intermittent delayed cutting may result in the profile 752 of the first midsole edge 156, instead of being a smooth oscillating wave, to be more irregular. In some examples, the profile 752 may resemble a serrated pattern. In other examples, the profile 752 may be irregular without a repeating pattern. The high points 754 and the low points 756 of the profile 752 will have a distance 758 between them that is equal to or less than the vertical oscillation distance 768 between the high points 762 and the low points 764 of the oscillating path 750 in that area of the cut. It is to be appreciated that the vertical oscillation distance 768 may not be equal to the reciprocating length RL, as the blade may be translating vertically during the lateral motion.

As noted above, in examples of the present disclosure the carved sipe may be formed with one sidewall having an overcut portion to account for the midsole material's reaction to the reciprocating motion of the blade. In particular, the foam of the midsole may compress or be pulled by the reciprocating blade to a greater extent during a second cut, since the structure of the nearby foam has been compromised by the first cut. Thus, it is preferable to form at least one of the sidewalls with an overcut to ensure that at least one of the sidewalls fully extends to the desired interior edge. While it is possible to form a carved sipe by overcutting both sidewalls past the desired interior edge, this may result in a sole structure that is more susceptible to undesired splaying or other deformation. Instead, the reciprocating blade for the second cut may be guided so that the oscillating path only partially intersects the intended interior edge, which may result in the intermittent perforations or slits in the opposing sidewall as described above.

FIG. 9A depicts a schematic plan view of a footwear component manufacturing system 200 in a first configuration in accordance with aspects hereof. The system 900 includes one or more robots, such as first robot 906 and second robot 910, to move a component, such as a sole structure 104, into proximity with various other system components, such as a scanning station 902, a first cutting station 904 and a second cutting station 908.

Each cutting station 904, 908 includes a blade mounted on a reciprocating mechanism. The blades and their reciprocating mechanisms may be the same or they may be different. It is contemplated that for each cutting station, the non-reciprocating components of the reciprocating mechanism are fixed in place, so that the blade reciprocates but otherwise remains fixed in the same spatial position, with the robot maneuvering the sole structure into contact with the blade accordingly to perform the desired siping. In other examples, the system may be configured so that the sole structure is fixed in place while the blade is maneuvered accordingly to form the desired sipes.

Each robot 906, 910 may comprise an articulated arm and a grasper to securely grasp and maneuver a sole structure into and through different orientations and position. In examples, a robot having a robot arm with six degrees of freedom (e.g., a 6-axis robotic arm) may be used. The grasper is configured to grasp the sole structure securely and in a manner that avoids the grasper potentially interfering with other manufacturing steps (e.g., the cutting of the sipes by the reciprocating blade). In examples, a sole structure 104 may include one or more features (e.g., guide holes in its upper surface 214) that the grasper (or other component of the robot arm) may interface with to better secure or more consistently position the sole structure relative to the grasper.

The scanning station 902 includes a scanner that precisely determines the positioning and orientation of a sole structure being held in the grasper of a robot arm, relative to one or more reference points on or in proximity to the grasper or other component of the robot arm. In examples, the scanner includes a physical probe that contacts one or more surfaces of the sole structure to determine its positioning and orientation. In other examples, one or more lasers or cameras are used to determine the position and orientation of the sole structure.

Thus, in example configurations, such as the configuration depicted in FIG. 9A, the use of multiple robots (906, 910) may allow multiple sole structures to be processed simultaneously by one or more of the system components. For example, first robot 906 can move a sole structure to scanning station 902 so that the positioning of the sole structure 104 relative to one or more reference points of the first robot can be determined or confirmed. The first robot 906 can then bring the sole structure 104 to a first cutting station 904 so that the sipes may be formed into the sole structure 104 while a second robot 910 brings a second sole structure 104 to the scanning station 902 for calibration. In the example shown in FIG. 9A, the system may also include one or more conveyor belts or other conveyance mechanisms for supplying sole structures for the system 900 to sipe and carrying away completed ones. For example, a first conveyor belt 912 may bring sole structures 920 to be siped within reach of the first robot 906 and the second robot 910, and a second conveyor belt 914 may carry completed (siped) sole structures 922 away.

It is to be appreciated that other system configurations in accordance with the present disclosure are also contemplated. One such alternative configuration is shown in FIG. 9B, in which both cutting stations 904, 908 are within reach of both robots 906, 910. This configuration may be advantageous when a sole structure requires being cut by two different types of blades, with the first blade being used by the first cutting station 904 and the second blade being used by the second cutting station 908. It is further contemplated that one or more system components, instead of being fixed in a particular location, may move relative to the other components, e.g., by being mounted on a conveyance. For example, the robot arms, cutting mechanisms or the scanner may be mounted on a track or a wheeled cart.

It is to be appreciated that FIGS. 9A and 9B is intended to only depict the general positioning of the components of the system, and that one of skill in the art would be able to determine the appropriate distances between these components depending upon factors such as the length of each robot arm and the working distance or radius of the grasper relative to a base of the robot arm during operation. Further, the schematic illustrations of FIGS. 9A and 9B are also not limiting as to size, location, or scale, and it is also contemplated that one or more components may be omitted from the system and/or that one or more components may be introduced to the system.

As seen in a second example of a sole structure 104 shown in FIGS. 10A-D, the sole structure 104, in addition to a plurality of carved sipes 400, may also comprise a plurality of slit sipes 130 that are generally oriented in the transverse direction between the lateral edge 107 and the medial edge 108 of the perimeter 106. As used herein, a “slit sipe” is a sipe formed by one pass of the reciprocating blade through the sole structure; the resulting sipe will have opposing sidewalls that, instead of having a permanent gap between them, will remain adjacent to and in contact with each other when the sole is in a relaxed and un-flexed state, but that may rotate or slide with respect to each other in response to forces on the sole structure. The slit sipes 130 may facilitate the bending or twisting of the sole structure 104 during movement that may allow for greater conformance to the user's foot, and additionally, allow the sole structure 104 to impart the feeling or sensation of barefoot running or movement to a user. While the example shown in FIG. X has slit sipes 130 that extend through both the lateral side 16 and the medial side 18 of the sole structure 104, in other examples one or both ends of a slit sipe 130 may not extend to the perimeter 106 of the sole structure 104 and instead be contained within the perimeter 106.

The intersection of the carved sipes 400 and slit sipes 130, together with the perimeter 106 of the sole structure 104, may further define siped portion 220 into a plurality of sole elements 830, each with its own outsole element 117. As seen in FIGS. 10B-D, the slit sipes 130 and carved sipes 400 may separate adjacent sole elements 830 from each other (in contrast to the connected sole elements 230 of the sole structure in FIG. 2), which may further increase the flexibility of the sole structure to respond to forces in the longitudinal, transverse, vertical and torsional directions, or a combination of any of the foregoing. The different intersections of the carved sipes 400 and the slit sipes 130 may result in different numbers of sole elements being formed within a particular region. For example, singe sole elements 839, 840 and 850 are formed in the forefoot region 10 and heel region 14 where the transverse slit sipes 130 do not intersect any carved sipes 400, but in the midfoot and forefoot region two transverse slit sipes may intersect with up to four carved sipes to create up to five separate sole elements (e.g., sole elements 832, 833, 834, 835, 836) between them and the outer perimeter 106 of the sole structure, and sole element 838 is defined by two transverse sipes (such as transverse sipes 130), an inner carved sipe (e.g., sipe 425), and the perimeter 106.

FIG. 10E shows another example of a sole structure 104 comprising two longitudinal carved sipes and a plurality of slit sipes 130, with a portion of the silt sipes intersecting the carved sipes 400 to form sole elements 230. As seen in the example of FIG. 10E, the carved sipes may include curvilinear as well as straight sections, and the ends may be carved to be more rounded. It is to be appreciated that the radius of curvature achievable for a sipe is determined in part by the thickness and width of the blade being used to form the sipe as well as the speed at which it is advanced through the sole structure material.

FIGS. 10F and 10G depict a fourth example of a sole structure 104 in accordance with the present disclosure that comprises carved sipes in both the longitudinal and transverse directions. As seen in FIG. 10G, the transverse carved sipes 450 may extend through the outer perimeter 106 of the sole structure 104.

As seen in FIGS. 10E-G, the present disclosure contemplates forming sipes (including carved sipes and slit sipes) with a reciprocating blade where a sipe may extend through a portion of the sole structure 104 without an outsole 110 (e.g., in the region of cutouts 113 in FIGS. 10D-F). It is contemplated that the cut forming such a sipe may be started in a part of the sole structure with no outsole, and then subsequently extend through a portion of the outsole where an outsole layer is present, or vice-versa. In other examples, the present disclosure contemplates forming sipes with a reciprocating blade in a sole structure with only one layer (e.g., only an outsole 110 or a midsole 104).

Methods for forming sipes in accordance with the present disclosure are also described herein. In a first method, as depicted in the flow chart 1100 in FIG. 11, in a first step a first robot (such as first robot 906) grasps a sole structure (or a jig holding the sole structure) and brings it in proximity to a scanner (such as the scanner in scanning station 902), where the scanner precisely determines the positioning and orientation of the sole structure relative to one or more reference points on or in proximity to the robot arm, such as a particular point on the grasper. In a second step 1104, the first robot brings the sole structure in proximity to a first cutting station (such as first cutting station 904) where a reciprocating blade cuts the sole structure to form one or more sipes, which may include carved sipes (such as carved sipes 400) as described herein. The carved portions of the sipe may then be removed, either while the sole structure is being held by the grasper or in a post-production step. Steps 1102 and 1104 can then be repeated with subsequent sole structures. In a series of optional steps, a second robot arm also performs the first step 1001 of scanning a sole structure at the scanner station, but then it may bring the sole structure in proximity to the first cutting station or a second cutting station (such as second cutting station 908) where the one or more sipes can be cut into the sole structure. A single scanner may alternate scanning sole structures held by the first robot and the second robot.

While the examples of the carved sipes described above generally show a carved sipe with two opposing sidewalls angled towards each other (e.g., at an acute angle relative to the ground-facing surface), other geometries are contemplated to be within the present disclosure. Some examples of alternative geometries are shown in FIGS. 12A-C. In FIG. 12A, a carved sipe 400 has a first sidewall 1200 a right angle 1204 to the ground-facing surface 112, while a second sidewall 1202 is angled at an acute angle 1206 relative to the plane defined by the ground-facing surface 112. In FIG. 12B, a carved sipe 400 having a first sidewall 1210 is angled at an angle 1214 greater than 90 degrees to the plane defined by the ground-facing surface 112. The resulting carved sipe 400 has an interior edge 170 that is positioned laterally over the ground-facing surface 112. As previously noted, a sole structure having multiple sipes with this geometry at different orientations to each other might result in mold undercuts that would prevent such a sole structure from being manufactured efficiently using conventional methods.

FIG. 12C illustrates a sole structure having an outsole 110, a first midsole layer 1250 and a second midsole layer 1252 adjacent to the first midsole layer 1250 along a midsole interface 1254. In examples, the first midsole layer 1250 and the second midsole layer 1252 comprise different properties, such as a difference in foam material, density, or color. A carved sipe 400 having a first sidewall 1230 may be formed by a single cut of a reciprocating blade. Thus, each of the side wall portions (first midsole portion 1232, second midsole portion 1234 and outsole portion 1236) are co-planar with each other.

A second sidewall 1222 of the carved sipe 400 of FIG. 12C comprises multiple faces at different angles formed by multiple cuts of the reciprocating blade. A second face 1224 extending from a second midsole edge 1221 and a third face 1226 extending from the second outsole edge 1240 meet at an intersection of the planes defined by the second face 1224 and the third face 1226 to define a third midsole edge 1228.

While not shown in the figures, it is contemplated that a carved sipe with the profiles shown in FIGS. 12A-C may have at least sidewall with an overcut portion as previously described above. Furthermore, it is contemplated that the cuts used to form the first, second or third faces may be performed in several different orders of operation.

Carved sipes formed in accordance with the present disclosure may offer a number of advantages over conventionally formed sipes. A conventional sipe, as depicted in FIGS. 12A-C, due to the inherent kerf width created by cutting with conventional methods, limits the geometries that may be obtained. For example, carved sipes with sharp interior edges or vertex ends cannot be achieved by conventional methods. The hot knife may introduce variability and or prevent a sharp (e.g., minimal radius of cutting) corner of a cavity. Moreover, use of a reciprocating blade to form sipes, including slit sipes and carved sipes, in accordance with the present disclosure provides greater flexibility in the designing of sipes for footwear. Certain geometries that are not achievable by conventional methods (due to the loss of material) are now possible with a reciprocating blade that can be maneuvered through the sole structure material without removing material from the sole structure unless it is desired to do so. Furthermore, because the blade can be withdrawn and reintroduced into the sole structure at a different orientations and angles, sharp corners or vertexes may be created that are not possible using conventional methods, such as those shown in some of the sample sipe patterns described above.

An article of footwear manufactured in accordance with the present disclosure is also more sustainable. Forming the sipes using the reciprocating blade minimizes small particles or vapors that may be produced using conventional cutting methods that create kerf or that melt or vaporize material. Instead, the larger portions of the sole structure that are carved out of the sole structure are easier to handle, either by discarding or recycling. The larger chunks also make it easier to separate the carved out pieces into their respective portions (outsole portion and midsole portion), making their ability to be recycled (e.g., repolymerized) more achievable. Moreover, powering a reciprocating blade in accordance with the present disclosure also typically requires less energy than the conventional methods of using a hot knife or laser cutting apparatus.

The following clauses represent example embodiments of concepts contemplated herein. Any one of the following clauses may be combined in a multiple dependent manner to depend from one or more other clauses. Further, any combination of dependent clauses (clauses that explicitly depend from a previous clause) may be combined while staying within the scope of aspects contemplated herein. The following clauses are examples and are not limiting.

Claus 1. An article of footwear, comprising: an upper; and a sole structure, the sole structure comprising: an outsole having a ground-facing surface; a midsole; and a sipe extending through the outsole into the midsole, the sipe comprising: a first face defining a first surface comprising a first midsole surface portion that is coplanar with a first outsole surface portion, wherein the first surface intersects the ground-facing surface at a first angle at a first location, a second face defining a second surface, wherein: the first face and the second face converge along an interior edge, and the first face and the second face defining a cavity within the sole structure.

Clause 2. The article of footwear according to clause 1, wherein the first outsole surface portion is adjacent to the first midsole surface portion along an interface, and the first face comprises a first plurality of striations, each of the first plurality of striations traversing the interface without a change in orientation.

Clause 3. The article of footwear according to any of clauses 1 to 2, wherein a convergence angle between the first face and the second face is less than 30 degrees.

Clause 4. The article of footwear according to clause 3, comprising a first vertical distance between the first location and the interior edge, and wherein the first face intersects the ground-facing surface at a second angle at a second location spaced apart from the first location, wherein the second angle is steeper than the first angle and a second vertical distance between the second location and the interior edge is greater than the first vertical distance.

Clause 5. The article of footwear according to any of clauses 1 to 4, wherein the first outsole surface portion comprises an outsole material and the first midsole surface portion comprises a midsole material, the outsole material and the midsole material having different densities.

Clause 6. The article of footwear according to any of clauses 1 to 5, wherein the first face extends beyond the interior edge.

Clause 7. The article of footwear according to clause 6, wherein the second face comprises a plurality of non-uniform sections.

Clause 8. An article of footwear, comprising: an upper; and a sole structure, the sole structure comprising: an outsole having a ground-facing surface; a midsole; and a sipe extending through the outsole into the midsole, the sipe comprising: a first face defining a first surface having a first outsole edge and a first midsole edge, the first outsole edge defined at a first intersection of the first face and the ground-facing surface and the first midsole edge defined at an opposite end of the first face from the first outsole edge; and a second face defining a second surface; wherein the first outsole edge is on a first side of a plane defined by the second face and the first midsole edge is on a second side of the plane.

Clause 9. The article of footwear according to clause 8, wherein the second surface comprises a second outsole edge and a second midsole edge, the second outsole edge defined at a second intersection of the second face and the ground-facing surface and the second midsole edge defined at an opposite end of the second face from the second outsole edge.

Clause 10. The article of footwear according to clause 9, the sipe comprising a longitudinal axis and a first plane orthogonal to the longitudinal axis, wherein a first length between the first outsole edge and the first midsole edge at the first plane is greater than a second length between the second outsole edge and the second midsole edge at the first plane.

Clause 11. The article of footwear according to any of clauses 9 to 10, wherein the second midsole edge intermittently intersects the first surface.

Clause 12. The article of footwear according to any of clauses 8 to 11, wherein: the midsole comprises a first midsole layer and a second midsole layer between the first midsole layer and the outsole; and the first face extends through the second midsole layer into the first midsole layer.

Clause 13. The article of footwear according to clause 12, wherein the first midsole edge traverses an interface of the first midsole layer and the second midsole layer.

Clause 14. The article of footwear according to clause 13, wherein the first midsole layer and the second midsole layer comprise a different property.

Clause 15. The article of footwear according to clause 14, wherein the different property is one of a color, a foam density, and a foam material.

Clause 16. An article of footwear, comprising: an upper; and a sole structure, the sole structure comprising: a ground-facing surface; and a sipe extending into the sole structure, the sipe comprising: a first face defining a first surface having a first internal edge, a second face defining a second surface, the second surface having a second internal edge, wherein the first face comprises a plurality of perforations aligned with the second internal edge.

Clause 17. The article of footwear according to clause 16, wherein the plurality of perforations each comprise a slit extending into the first face.

Clause 18. The article of footwear according to clause 17, wherein each slit comprises a slit face that is aligned with a plane defined by the second surface.

Clause 19. The article of footwear according to clause 18, wherein the first face comprises a first outer edge defined at an intersection of the first face and the ground-facing surface.

Clause 20. The article of footwear according to any of clauses 16 to 19, wherein: the second face comprises a third internal edge opposite the second internal edge, and the sipe comprises a third face adjacent to the second face, the third face defining a third surface having a second outer edge defined at an intersection of the third face and the ground-facing surface and meeting the first face along the third internal edge.

Clause 21. A method of manufacturing an article of footwear, comprising:

• • providing a sole structure comprising an outsole having a ground-facing surface and a midsole; cutting through the outsole into the midsole with a reciprocating blade to form a first face defining a first surface comprising a first midsole surface portion that is coplanar with a first outsole surface portion; cutting through the outsole into the midsole with the reciprocating blade to form a second face defining a second surface, wherein the first face and the second face converge along an interior edge; and
  • removing material between the first face and the second face to define a cavity within the sole structure.

Clause 22. The method according to clause 21, wherein the reciprocating blade comprises a plain cutting edge without serrations.

Clause 23. The method according to any of clauses 21 to 22, wherein the reciprocating blade reciprocates at a frequency between 140 and 200 hertz.

Clause 24. The method according to any of clauses 21 to 23, wherein cutting through the outsole into the midsole creates striations on the first surface, the striations traversing an interface between the first outsole surface portion and the first midsole surface portion without a change in orientation.

Clause 25. The method according to any of clauses 21 to 24, wherein the first face and the second face converge along the interior edge at a convergence angle of less than 30 degrees.

Clause 26. The method according to any of clauses 21 to 25, wherein the first face intersects the ground-facing surface at a first angle at a first location and at a second angle at a second location spaced apart from the first location, wherein the second angle is steeper than the first angle.

Clause 27. The method according to any of clauses 21 to 26, wherein the first outsole surface portion comprises an outsole material and the first midsole surface portion comprises a midsole material, the outsole material and the midsole material having different densities.

Clause 28. The method according to any of clauses 21 to 28, wherein cutting through the outsole into the midsole to form the first face comprises extending the first face beyond the interior edge.

Clause 29. A method of manufacturing an article of footwear, comprising: providing a sole structure comprising an outsole having a ground-facing surface and a midsole; cutting through the outsole into the midsole with a reciprocating blade to form a first face of a sipe defining a first surface having a first outsole edge and a first midsole edge, the first outsole edge defined at a first intersection of the first face and the ground-facing surface; cutting through the outsole into the midsole with the reciprocating blade to form a second face of the sipe defining a second surface; and wherein the first outsole edge is on a first side of a plane defined by the second face and the first midsole edge is on a second side of the plane.

Clause 30. The method according to clause 29, wherein the second surface comprises a second outsole edge and a second midsole edge, the second outsole edge defined at a second intersection of the second face and the ground-facing surface.

Clause 31. The method according to clause 30, wherein a first length between the first outsole edge and the first midsole edge at a first plane orthogonal to a longitudinal axis of the sipe is greater than a second length between the second outsole edge and the second midsole edge at the first plane.

Clause 32. The method according to any of clauses 30 to 31, wherein cutting through the outsole into the midsole to form the second face comprises forming the second midsole edge to intermittently intersect the first surface.

Clause 33. The method according to any of clauses 29 to 32, wherein the midsole comprises a first midsole layer and a second midsole layer between the first midsole layer and the outsole, and cutting through the outsole into the midsole to form the first face comprises extending the first face through the second midsole layer into the first midsole layer.

Clause 34. The method according to clause 33, wherein the first midsole edge traverses an interface of the first midsole layer and the second midsole layer.

Clause 35. The method according to clause 34, wherein the first midsole layer and the second midsole layer comprise different properties selected from a color, a foam density, and a foam material.

Clause 36. A method of manufacturing an article of footwear, comprising: providing a sole structure comprising a ground-facing surface; cutting into the sole structure with a reciprocating blade to form a first face defining a first surface having a first internal edge; cutting into the sole structure with the reciprocating blade to form a second face defining a second surface having a second internal edge; and forming a plurality of perforations in the first face aligned with the second internal edge.

Clause 37. The method according to clause 36, wherein forming the plurality of perforations comprises creating slits extending into the first face.

Clause 38. The method according to clause 37, wherein each slit comprises a slit face that is aligned with a plane defined by the second surface.

Clause 39. The method according to any of clauses 36 to 38, wherein the first face comprises a first outer edge defined at an intersection of the first face and the ground-facing surface.

Clause 40. The method according to clause 39, further comprising: forming a third face adjacent to the second face, the third face defining a third surface having a second outer edge defined at an intersection of the third face and the ground-facing surface and meeting the first face along a third internal edge, wherein the second face comprises the third internal edge opposite the second internal edge.

Many different arrangements of the various components depicted, as well as components not shown, are possible without departing from the scope of the claims below. Embodiments in this disclosure are described with the intent to be illustrative rather than restrictive. Alternative embodiments will become apparent to readers of this disclosure after and because of reading it. Alternative means of implementing the aforementioned can be completed without departing from the scope of the claims below. Certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations and are contemplated within the scope of the claims.

In the preceding detailed description, reference is made to the accompanying drawings which form a part hereof wherein like numerals designate like parts throughout, and in which is shown, by way of illustration, embodiments that may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. Therefore, the preceding detailed description is not to be taken in the limiting sense, and the scope of embodiments is defined by the appended claims and their equivalents.