ARTICLE OF FOOTWEAR WITH SIPES

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional patent application claims priority to 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.

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 perspective view of the article of footwear of FIG. 1 with the sole structure in a relaxed state.

FIG. 3 illustrates a side view of the sole structure of the article of footwear of FIG. 1 with the sole structure in a relaxed state.

FIG. 4 illustrates a cross-sectional view of the sole structure of FIG. 2.

FIG. 5 illustrates a perspective view of a portion of the sole structure of FIG. 2 in a flexed state.

FIG. 6A illustrates a side view of the portion of the sole structure of FIG. 5 in a flexed state.

FIG. 6B illustrates an enlarged close-up view of a portion of FIG. 6A.

FIG. 6C illustrates a side view of a first sidewall of the sipe in FIG. 6B.

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. 7E illustrates an example of a path of a reciprocating blade cutting through a sole structure in accordance with the present disclosure.

FIG. 8 illustrates a magnified view of a sole structure with representations of a conventional sipe and a slit sipe 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-D illustrates a sole structure with a conventional sipe in different situations.

FIGS. 13A-D illustrates a sole structure with a slit sipe in accordance with the present disclosure in different.

DETAILED DESCRIPTION

The present disclosure relates to an article of footwear including a sole structure having one or more sipes that are formed by cutting or 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 sipe has no appreciable gap or kerf width between its opposing sidewall faces. Stated differently, the material of the sole structure is divided along the length of the sipe but since substantially no material is removed or melted by the cutting process the resulting sidewall faces on either side of the cut remain in contact with each other when the sole is in a relaxed (un-flexed) state (such as when the article of footwear is in an unworn, resting state) but are able to rotate away from each other or slide in relation to each other when the sole structure is flexed during movement. As used herein, “unworn,” means that the article of footwear is not being worn, i.e., a user's foot is not presently in the article of footwear, but it does not necessarily mean that the article of footwear has never been worn. Stated differently, an article in an unworn state is an article in a state that is absent external structures, forces, and/or deformations other than traditional environmental conditions. As used herein, “resting” means that the article, such as an article of footwear, is not being subject to external forces other than the force of gravity acting upon the article itself and a normal force from a surface that the article may be resting upon. Stated differently, an article in an unworn, resting state is an article in a state that is absent external structures, forces, and/or deformations other than traditional environmental conditions.

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 the present disclosure, sipes are cut into a sole structure using a reciprocating blade with a slicing edge and tip to form a slit. 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.

In a typical sole structure comprising a midsole and an outsole with a ground-facing surface, a sipe formed by one pass of the blade through the sole structure (hereinafter referred to as a “slit 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. Each of the opposing sidewalls has a face that extends from an outsole edge at the ground-facing surface to an interior edge within the sole structure (e.g., within the midsole). Thus, each of the opposing sidewalls with have an outsole portion and a midsole portion, with both portions being co-planar with each other, and sharing a common interior edge in the midsole. That is, the opposing sidewalls of the slit sipe extend from their respective outsole edges at the ground-facing surface of the outsole and meet at an apex at a point within the midsole of the sole structure, which when extended along the length of the sipe defines its interior edge. In other examples, the slit 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 reciprocating cutting action used to form sipes, including slit 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 slit 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. Furthermore, in examples the interior edge formed by the reciprocating cutting action will have, in examples, a non-linear profile due at least in part to the reaction (e.g., resilience) of the materials of the midsole and the outsole to the force generated by the motion of the blade.

A sole structure with slit sipes in accordance with the present disclosure, as further discussed herein, may provide several benefits and advantages over conventionally formed sipes. For instance, the slit sipes of the present disclosure may be less susceptible to small rocks or other debris on the ground being lodged into the interior of the sipe, and any debris that does enter the sipe may be easier to remove as compared to traditional sipes having a kerf width. An article of footwear manufactured with sipes in accordance with the present disclosure may also be more sustainable and durable, and the sipes may be formed with greater design flexibility.

Turning now to FIGS. 1 and 2, different views of 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.

As seen 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 “slit sipe” as used herein is a sipe comprising opposing sidewalls that are parallel to and in contact with each other when the sole structure is in a neutral or relaxed position, with the two sidewalls converging at an apex within the interior of the sole structure. A “carved sipe” is formed by multiple converging cuts and then removing of intervening material between opposing sidewalls defining a sipe cavity between them.

In the sole structure 104 of FIG. 2 a plurality of slit sipes 130 extend from the lateral side 16 of the sole structure 104 to the medial side 18 in a generally transverse orientation. In examples, the slit sipes 130 may be spaced relatively evenly apart from each other, or there may be variations in spacing between them. In examples, at least one of the slit sipes 130 may be linear or curvilinear. In examples, at least one of the slit sipes 130 may be contained within the perimeter 106 or they may extend to/through the perimeter 106. In examples, at least one of the slit sipes 130 may form open segments (e.g., a start position separated from a stop position, such as a line segment) or closed segments (e.g., a start position is indistinguishable from an end position, such as a circle). Adjacent slit sipes 130 may be generally parallel to each other, or they may be angled relative to one or more slit sipes 130 and may intersect each other. In other examples, as further discussed below, one or more sipes (including but not limited to slit sipes) may extend generally in the longitudinal direction (e.g., from the heel region to the forefoot region or vice-versa) or diagonally. 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.

In the example of FIG. 2 and as further shown in FIG. 3, each of the plurality of slit sipes 130 extends through both the lateral side 16 and the medial side 18 of the sole structure 104. Stated differently, the sidewall of the sole structure 104 along its perimeter 106 is partially cut through by the ends of each slit sipe 130. In other examples, as further discussed below, 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 slit sipes 130 extend through the entire outsole thickness 116 and into the midsole 120. As shown in the cross sectional view of the sole structure 104 in FIG. 4, the midsole 120 thus comprises a connecting portion 210 and siped portion 220. Connecting portion 210 may extend along the length of sole structure 104 from heel region 14 to forefoot region 10. Additionally, connecting portion 210 may have a lower surface 212 and an upper surface 214, which may comprise an upper surface 214 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. For example, in the article 100 described herein, 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 a plurality of interior edges 170 of the slit sipes 130. 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 may comprise only a portion of the entire sole structure 104. For example, in the sole structure 104 shown in FIG. 4, there are no sipes, and therefore no siped portion, in the heel region 14. In an alternative example the slit sipes 130 extend through only a portion of the outsole thickness 116 and do not extend into the midsole 120.

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.

Each slit sipe 130 may have a depth 145 (measured from the ground-facing surface 112 to the interior edge 170) that may be varied along the length of sole structure 104. In examples, the depth 145 of a sipe is consistent along its length. In other examples, the depth of a sipe may vary along the length, which in turn may influence the flexibility of the sole structure 104 along the length of the sipe differently. In some examples, part or all of a sipe may have a depth that is less than the outsole thickness 116. In other examples, part or all of a sipe may extend through the entire outsole thickness 116. The depth of each slit sipe 130 may be similar to one or more other slit sipes 130 or they may differ from each other.

By placing sipes in various areas that correspond to flex points of a foot, the sole structure 104 may more readily react to the bending motions of a foot during use. In other examples, sipes may not be present in areas that correspond to flex points of a foot in order to limit the flex of sole structure 104, which may help to prevent overextension of parts of a foot.

The plurality of slit sipes 130 may define siped portion 220 into a plurality of sole elements 230, each with its own outsole element 117. In examples, the sole elements 230 may have various shapes and sizes, influenced by the number, shape, position, depth, angle and orientation of the plurality of sipes and the shape (e.g., perimeter/peripheral edge) of the sole structure. For example, referring back to FIG. 2, the shape of first sole element 172 (and first outsole element 118) is influenced by the shape of the perimeter 106 of the sole structure 104 in the forefoot region 10 at or near the toe as well as first slit sipe 131, while the shape of a second sole element 174 (and shape of second outsole element 119) in the midfoot region 12 is influenced by the shape of the lateral edge 107 of the perimeter 106, the medial edge 108 of the perimeter 106, second slit sipe 132 and third slit sipe 133. In other examples where the outsole does not completely match the ground-facing surface 122 of the midsole 120, the shape of an outsole element 117 may only be partially influenced by the sipes and the sole structure perimeter and the ground-facing surface 122 of the midsole 120 may form part of the overall ground-facing surface of that sole element 230.

The sole structure 104 of article 100 as seen in FIGS. 1-4 is in a neutral, un-flexed state in which the slit sipes 130 are closed. In this state the first sidewall 150 and the second sidewall 160 on opposite sides of the slit sipe 130 are in contact with each other. When the sole structure 104 is flexed, such as shown in FIGS. 5 and 6A, the slit sipes 130 are opened or expanded, with first sidewalls 150 and second sidewalls 160 rotated away from each other. The first sidewall 150 and the second sidewall 160 are angled apart but converge with each other at an apex, which extended along the length of the slit sipe 130 comprises the interior edge 170 of the slit sipe 130.

Turning now to a closer look of the expanded slit sipe 130 and its first sidewall 150 in FIGS. 6B-C, the first sidewall 150 comprises a first face 151 that extends from a first outsole edge 158 at the ground-facing surface 112 to the interior edge 170. First face 151 thus includes an outsole portion 152 and a midsole portion 153 adjacent to each other along the interface 125 of the outsole 110 and the midsole 120. As see in FIG. 6B, the outsole portion 152 and the midsole portion 153 are coplanar with each other. Stated differently, the first face 151 does not change its orientation between the outsole portion 152 and the midsole portion 153. Additionally, as seen in FIG. 6C, a first plurality of striations 154 extend across the first face 151, with at least some of the striations 154 traversing through the interface 125 without a change in orientation. As further discussed below, the striations 154 may be created by the cutting action of a reciprocating blade, which also creates a non-linear profile for the interior edge 170 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.

It is to be appreciated that the second sidewall 160 with a second face 161 extending from a second outsole edge 168 to the interior edge 170 will also share similar characteristics of the first sidewall 150, including (when striations are present on the first sidewall) a second plurality of striations, at least some of which matching the characteristics of the first plurality of striations 154 on the first face 151. The profile and contours of the second sidewall 160 and will also mirror the profile and contours of the first sidewall 150.

While FIG. 5 shows the slit sipes 130 facilitating the flexing of the sole structure 104 in a particular direction (e.g., bending about a transverse axis), it is to be appreciated that the slit sipes 130, by at least partially disconnecting previously integrated material of sole structure 104, may also facilitate the flexing of the sole structure in other ways, such as by bending about a longitudinal axis or in response to a twisting action.

The sipes of the present disclosure, including the slit sipes 130 described above, 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 a 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 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 form a slit sipe the blade 700 may aligned to the ground-facing surface 112 of the outsole 110 prior to cutting at the desired angle for the cut and resulting slit sipe. In the example shown in FIG. 7C the blade 700 is aligned to form a cut that is generally perpendicular to the ground-facing surface 112, but angled cuts are also contemplated to be within the scope of the present disclosure (see e.g., FIG. 10G hereinafter). The sole structure 104 may then be advanced towards the reciprocating blade 700. 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., a section of the midsole may compressed so that a first length 790 measured from a fixed point in the midsole 120 to the outsole 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 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 100 mm/second when the blade 700 is cutting at a depth about 1 mm to about 10 mm.

As discussed above with respect to FIGS. 5 and 6A-C, 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. 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 154 will cross the interface 125 of the outsole 110 and the midsole 120 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. 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 interior edge 170 formed by the blade cutting though the material of the sole structure 104 may have a non-linear profile. In examples, the interior 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. 7E, 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 and blade tip edge 706 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 interior edge 170, 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 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.

Another characteristic of a cut made by a reciprocating blade in accordance with the present disclosure is that the cell structure of the foam that is cut may be divided but is not otherwise altered or destroyed. Typically a foam material suitable for use in a midsole may have a cell size average, e.g., by length of a longest cell dimension, of less than 1 mm. Cell size is contemplated to be measured using the testing standard provided by ASTM D3576-20, in an example. When using conventional methods for forming a sipe in a sole structure, the width of the gap between the sidewalls of the sipe is many times greater than that of the foam cell walls. Accordingly, a cell wall of a cell in the foam that is partially cut during the sipe-forming process will have the rest of the cell wall either removed from the sole structure (e.g., as kerf or vaporized) or altered (melted into one of the sidewalls).

In contrast, a sipe formed in accordance with the present disclosure will have cells that have been divided by the blade with one part of the cell wall on one sidewall of the sipe and a second part of the same cell wall on the opposing sidewall of the sipe. Because the reciprocating blade creates a cut that has little to no (e.g., less than 1 micrometer) of kerf width, it is possible for portions of an individual cell wall to be present on both sides of the resultant sipe.

This unique characteristic of the present disclosure is represented by the illustration in FIG. 8. An enlarged view of a sole structure 104 with an outsole 110 and midsole 120 comprising a closed cell foam is illustrated, with representative cells 810, 820, 830 and 840 depicted in the volume of midsole 120. A slit sipe 130 formed by a reciprocating blade in accordance with the present disclosure extends through and bisects cell 830. As used herein, to “bisect” a cell wall means to divide it into two portions with little to no loss of material; it does not require that the two portions are equally sized. Thus, the slit sipe 130 bisects cell 830 into first cell wall portion 832 and second cell wall portion 834. The first cell wall portion 832 is on the surface of the first sidewall 150 and the second cell wall portion 834 is on the surface of the second sidewall 160, adjacent/opposite each other. It is also seen in FIG. 8 that the slit sipe 130 may also bisect an integrally-formed portion of the outsole 110.

In contrast, the dashed lines 850 in FIG. 8 show the volume of material of the sole structure (including portions of the outsole 110 and midsole 120) that would be removed (e.g., via kerf or vaporization) or melted by a conventional siping process, in which the sipe would have a width 851 between a first sidewall 852 and a second sidewall 853. Cells 930 and 940 would be eliminated from the midsole 120, and cells 810 and 820 would have portions of their cell walls destroyed. Accordingly, for a conventionally formed sipe no cell of the midsole foam has a portion of its cell wall on both sidewalls of the conventional sipe. It is also to be appreciated that the density of the foam at the sidewall face of a slit sipe in accordance with the present invention (e.g., midsole portion 153 in FIG. 6C above) has the same density as the midsole foam interior to the sidewall face. In contrast, a conventional sipe formed by a hot blade or laser will have the density of the foam along its sidewalls altered due to the melting of the foam during the cutting process that results in a higher density at the melted surface(s) as compared to a sidewall formed as a slit sipe.

While the above description describes a representative closed cell foam, the same principles apply to open cell foam structures that may be used in a sole structure for an article 100; that is, a cell wall of an open-cell foam structure may be bisected by a reciprocating blade so that matching portions of the cell wall may be identifiable on opposing sidewalls of the resultant sipe. It is also to be appreciated that the reciprocating blade, in forming the slit sipe, may also bisect an integrally-formed portion of the outsole 110.

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.

While the slit sipes 130 in the example of article 100 described above are generally transversely oriented (e.g., running from the lateral side 16 to the medial side 18), it is contemplated that many different patterns and combinations of sipes can be practiced in accordance with the present disclosure. FIGS. 10A-G illustrate some examples of different sipe patterns, but many others are possible.

For example, in the sole structure 104 depicted in FIG. 10A, slit sipes 711 formed in accordance with the present disclosure may be curved, contoured or undulating. It is to be appreciated that the radius of curvature achievable for a slit 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. 10B and 10C depict sole structures 104 with slit sipes (720, 730) that intersect with each other to form a tessellated pattern of sole elements (722, 724, 732, 734). As seen, the perimeter of some sole elements, such as sole element 724 and sole element 734, may be partially defined by the perimeter of the sole structure. The sole elements, during flexing or twisting of the sole structure, may expand away from each other or press against each other to increase or restrict the flexibility of the sole structure 104 in reaction to different forces. FIG. 10B also illustrates that a single slit sipe 740 by itself may be used to form a sole element 742 in accordance with the present disclosure.

FIG. 10D depicts a sole structure in which a plurality of carved sipes 400 that extend longitudinally in the forefoot region 10 and the midfoot region 12 intersect the transversely-oriented slit sipes 130. The carved sipes 400, in which material between two cuts forming opposing sidewalls is removed, may expose portions of the midsole 120. The carved sipes 400 may be formed with a reciprocating blade as described herein. FIG. 10D also illustrates an article of footwear in which surface area of the ground-facing surface 112 of the outsole 110 does not match the surface area defined by the outer perimeter 106. For example, the outsole of FIG. 10D comprises cutouts 113 on the medial and lateral sides of the outsole 110 near the heel region 14, so that the ground-facing surface 122 of the midsole 120 is exposed. Also as seen in FIG. 10D, the present disclosure contemplates forming 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 cutout 113). 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. The carved sipes 400 may have a similar depth to the slit sipes 130 or they may be different. 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).

FIGS. 10E and F illustrate an example of a sole structure 104 in which the ground-facing surface 112 may comprise one or more outsole elements such as raised portions 115 that may provide additional traction or cushioning to sole structure 104.

Additionally, while the slit sipes 130 described above have sidewalls that are generally perpendicular to the plane of the ground-facing surface, it is contemplated to be with the scope of the present disclosure to form sipes with angled sidewalls. As shown in FIG. 10G, a sole structure 104 may have sipes that are cut into the sole structure at angles that are different than perpendicular. In the cross sectional view of FIG. 10G of a sole structure 104, slit sipe 1008 in the middle of the sole structure 104 is cut into the sole structure 104 at a generally perpendicular angle to the plane of the ground-facing surface 112. However, the slit sipes in and closer to the forefoot region 10, such as slit sipes 1010, 1012, 1014 and 1016 are cut into the sole structure at respective angles 1025, 1026, 1028 and 1030 that are angled progressive more towards the toe of the sole structure 104, while slit sipes 1002, 1004 and 1006 in or near the heel region 14 are cut into the sole structure at respective angles 1020, 1022 and 1024 that are angled progressively more towards the heel of the sole structure 104. Cut path lines 1050 are shown to illustrate how the angled slit sipes can be configured and positioned to avoid interference during the cutting process by structures on the outsole 110 like raised portions 115.

Methods for forming slit 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 a robot arm of the 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 slit sipes (such as slit sipes 130) as described herein. 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.

Slit sipes formed in accordance with the present disclosure may offer a number of advantages over conventionally formed sipes. A conventional sipe 1210 in a conventional sole structure 1200, as depicted in FIGS. 12A-C, due to the permanent gap of the sipe having a width 1212 at rest between its sidewalls 1220 is always open and thus susceptible to small rocks or other debris on the ground being lodged into the interior of the sipe. In particular, the impact of the sole structure 1200 hitting the ground during activity (e.g., running) may force a piece of debris 1230 deep into the interior of the sipe 1210 when it is rotated further open (e.g., as shown in FIG. 12B). Since the sole structure 1200 typically comprises a flexible material, a piece of debris significantly larger than the width 1212 of the sipe 1210 may end up lodged deep into the interior of the sipe 1210 (e.g., as shown in FIG. 12C), which may be difficult to remove, even requiring the use of a tool to grasp, wrench or lever it out. In contrast, a slit sipe 1310 in a sole structure 1300 in accordance with the present disclosure has no space between its lateral sidewalls 1320 (as shown in FIG. 13A), particularly near the interior edge 1322. Thus, the size of the debris 1330 that is able to end the sipe 1310 is smaller and is also prevented from entering into the sipe as deeply (FIG. 13B), making any debris that does become lodged easier to remove, e.g., by flexing the sipe 1310 open again (FIG. 13C).

An article of footwear including sipes in accordance with the present disclosure may also be more durable than articles of footwear with conventional sipes. With reference to FIG. 13D, because the slit sipe 1310 has no kerf width, the lateral sidewalls 1320 of the slit sipe 1310 are in contact with each other (FIG. 13D) in an un-rotated state. Thus, the adjacent parts of the sole structure 1300 can provide support in the horizontal direction to each other against the weight of the user wearing the shoe. The elimination of the kerf width between the sidewalls 1320 of the slit sipe 1310 also prevents the sole structure 1300 from being flexed concavely in the downward (ground-facing) direction when certain forces are applied to the sole structure, in contrast to the conventional sipe 1210 shown in FIG. 12D, which may further increase the usable lifetime of the sole structure 1300.

An article of footwear manufactured in accordance with the present disclosure is also more sustainable. Forming the sipes using the reciprocating blade minimizes waste, particularly the small particles or vapors that may be produced using conventional cutting methods that create kerf or that melt or vaporize material. 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.

Moreover, use of a reciprocating blade to form sipes, including slit 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.

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.

Clause 1. An article of footwear, comprising: an upper; and a sole structure; the sole structure comprising: a midsole; an outsole attached to the midsole along an interface and comprising a ground-facing surface; and a first sipe extending from the ground-facing surface through the outsole into the midsole and comprising a first sidewall face, the first sidewall face comprising: a first midsole portion; a first outsole portion; and a first plurality of striations, each of the first plurality of striations traversing the interface without a change in orientation.

Clause 2. The article of footwear according to clause 1, wherein the first sipe further comprises a second sidewall face facing the first sidewall face, the second sidewall face comprising a second plurality of striations, each of the second plurality of striations matching one of the first plurality of striations.

Clause 3.The article of footwear according to clause 2, wherein the second sidewall face comprises a second midsole portion and a second outsole portion, and the first outsole portion is in contact with the second outsole portion when the article of footwear is in an unworn resting state.

Clause 4. The article of footwear according to any of clauses 2 to 3, wherein the first sidewall face and the second sidewall face converge at an interior edge within the midsole, the interior edge having a nonlinear profile.

Clause 5. The article of footwear according to any of clauses 1 to 4, wherein the first sipe extends from a lateral side of the sole structure to a medial side of the sole structure.

Clause 6. The article of footwear according to clause 5, wherein the first sipe is one of a plurality of sipes extending from the lateral side of the sole structure to a medial side of the sole structure.

Clause 7. An article of footwear, comprising: an upper; and a sole structure, the sole structure comprising: a midsole comprising a foam defined by a plurality of cell walls; and a first sipe extending into the midsole, the first sipe comprising a first sidewall and a second sidewall opposite the first sidewall, wherein the first sidewall and the second sidewall bisect at least one of the plurality of cell walls.

Clause 8. The article of footwear according to clause 7, wherein the midsole comprises a first cell wall previously defining a first cell, with a first portion of the first cell wall disposed on the first sidewall and a second portion of the first cell wall disposed on the second sidewall.

Clause 9. The article of footwear according to clause 8, wherein the first sipe has a kerf width of less than 1 micrometer when the article of footwear is in an unworn resting state.

Clause 10. The article of footwear according to any of clauses 8 to 9, wherein the plurality of cell walls comprise a plurality of closed cells and the first cell wall previously defined a first closed cell.

Clause 11. The article of footwear according to any of clauses 7 to 10, wherein the sole structure further comprises an outsole attached to the midsole and comprising a ground-facing surface, and the first sipe extends through the outsole into the midsole.

Clause 12. The article of footwear according to clause 11, wherein the first sidewall and the second sidewall bisect an integrally-formed portion of the outsole.

Clause 13. An article of footwear, comprising: an upper; and a sole, the sole comprising: a first sipe extending through the sole, the first sipe comprising: a first sidewall face, a second sidewall face opposite the first sidewall face, and an interior edge where the first sidewall face and the second sidewall face converge; wherein at least a first portion of the first sidewall face adjacent the interior edge is in contact with a second portion of the second sidewall face adjacent the interior edge when the article of footwear is in an unworn resting state.

Clause 14. The article of footwear according to clause 13, wherein the first sidewall face is rotatable away from the second sidewall face about the interior edge.

Clause 15. The article of footwear according to clause 14, wherein the interior edge comprises an irregular profile.

Clause 16. The article of footwear according to any of clauses 13 to 15, wherein the first sidewall face has a first contour, and the second sidewall face comprises a second contour that mirrors the first contour.

Clause 17. The article of footwear according to any of clauses 13 to 16, wherein the sole comprises a medial edge and a lateral edge, and the first sipe extends through the medial edge and the lateral edge.

Clause 18. The article of footwear according to clause 17, wherein the sole comprises a second sipe extending from the medial edge to the lateral edge.

Claus 19. The article of footwear according to any of clauses 13 to 18, wherein the sole comprises a second sipe that intersects the first sipe.

Clause 20. The article of footwear according to any of clauses 13 to 19, wherein the first sipe is formed by a reciprocating blade with a plain cutting edge.

Clause 21. A method of manufacturing an article of footwear, comprising: providing a sole structure comprising a midsole and an outsole attached to the midsole along an interface, the outsole comprising a ground-facing surface; and cutting a first sipe extending from the ground-facing surface through the outsole into the midsole using a reciprocating blade.

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

Clause 23. The method according to any of clauses 21 to 22, wherein the reciprocating blade reciprocates across a linear distance between 2 mm and 10 mm.

Clause 24. The method according to any of clauses 21 to 23, wherein cutting the first sipe comprises moving the reciprocating blade through the sole structure at a rate between 1 and 100 mm per second.

Clause 25. The method according to any of clauses 21 to 24, wherein the first sipe comprises:

• • a first sidewall face having a first plurality of striations, each of the first plurality of striations traversing the interface without a change in orientation; and a second sidewall face facing the first sidewall face, the second sidewall face comprising a second plurality of striations matching the first plurality of striations.

Clause 26. The method according to clause 25, wherein the first sidewall face and the second sidewall face are in contact with each other when the sole structure is in a relaxed state.

Clause 27. The method according to any of clauses 21 to 26, wherein the reciprocating blade has a cutting edge length between 20 and 100 mm and a cutting edge angle between 70 and 85 degrees.

Clause 28. A method of manufacturing an article of footwear, comprising: providing a sole structure comprising a midsole having a foam defined by a plurality of cell walls; cutting a first sipe extending into the midsole using a reciprocating blade, the first sipe comprising a first sidewall and a second sidewall opposite the first sidewall, wherein cutting the first sipe bisects at least one of the plurality of cell walls.

Clause 29. The method according to clause 28, wherein bisecting at least one of the plurality of cell walls comprises dividing a first cell wall into a first portion disposed on the first sidewall and a second portion disposed on the second sidewall.

Clause 30. The method according to clause 29, wherein the first sipe has a kerf width of less than 1 micrometer after cutting.

Clause 31. The method according to any of clauses 28 to 29, wherein the sole structure further comprises an outsole attached to the midsole, and cutting the first sipe comprises extending the first sipe through the outsole into the midsole.

Clause 32. The method according to clause 31, wherein the first sipe bisects an integrally-formed portion of the outsole.

Clause 33. The method according to any of clauses 28 to 32, wherein the reciprocating blade comprises a plain cutting edge.

Clause 34. A method of manufacturing an article of footwear, comprising: providing a sole; cutting a first sipe extending through the sole using a reciprocating blade, the first sipe comprising a first sidewall face, a second sidewall face opposite the first sidewall face, and an interior edge where the first sidewall face and the second sidewall face converge, wherein at least a first portion of the first sidewall face adjacent the interior edge is in contact with a second portion of the second sidewall face adjacent the interior edge after cutting.

Clause 35. The method according to clause 34, wherein the interior edge has an irregular profile.

Clause 36. The method according to any of clauses 34 to 35, wherein the first sidewall face has a first contour and the second sidewall face has a second contour that mirrors the first contour.

Clause 37. The method according to any of clauses 34 to 36, wherein the sole comprises a medial edge and a lateral edge, and cutting the first sipe comprises extending the first sipe through the medial edge and the lateral edge.

Clause 38. The method according to clause 37, further comprising cutting a second sipe extending from the medial edge to the lateral edge.

Clause 39. The method according to any of clauses 34 to 38, further comprising cutting a second sipe that intersects the first sipe.

Clause 40. The method according to any of clauses 34 to 39, wherein the reciprocating blade is mounted on a reciprocating mechanism and reciprocates while cutting the first sipe.

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.