Patent Description:
The present disclosure relates to a method of manufacturing an article of footwear by thermoforming the sole structure directly to the upper.

Articles of footwear typically have at least two major components, an upper that provides the enclosure for receiving the wearer's foot, and a sole secured to the upper that is the primary contact to the ground or playing surface. In conventional footwear construction, a sole structure may be molded into its final shape through a process such as compression molding or injection molding. Following this, the sole structure may be adhered to an upper, such as by applying an adhesive or cement to both the final sole, and to a strobel portion of an upper and securing the components together.

By manufacturing the article of footwear in this manner, certain designs may be prevented through the constraints presented when molding the sole. For example, molding undercuts are typically avoided (i.e., where an undercut is a void in the final part that is created by a portion of the mold that may impede the molded part from being freely removed from the molding cavity). Likewise, molding a multi-material geometry may be difficult or impossible to control if the various materials are, for example, layered within protrusions or other isolated features. <CIT> describes auxetic structures and a footwear with soles having auxetic structures. <CIT> describes sole structures and articles of footwear having an elongated hexagonal siping patter and/or a heel pocket structure.

The claimed invention is defined by the subject-matter of the independent claim. Specific embodiments are defined by the dependent claims.

The detailed description and the drawings or figures are supportive and descriptive of the present teachings, but the scope of the present teachings is defined solely by the claims. While some of the best modes and other embodiments for carrying out the present teachings have been described in detail, various alternative designs and embodiments exist for practicing the present teachings defined in the appended claims.

The present disclosure describes an article of footwear, method of manufacture, and intermediate sole structure that provides unique design advantages, both visually and in performance by creating certain sole geometry and structure while molding the intermediate sole structure, and by creating other sole geometry and structural attributes when separately thermoforming the intermediate sole structure to the upper.

The present designs may utilize siping and surface contouring within the intermediate sole structure to: create various protuberances extending out from the sole structure; create unique splaying designs; alter sole stiffnesses; and/or induce/alter various directional flexibility. Furthermore, in some embodiments, the intermediate sole structure may have a multi-material, layered construction that can then result in layered protuberances, locally altered cushioning properties, etc. Such designs, as described herein may generally be cost prohibitive and/or impossible to form through conventional, straight-from-the-mold sole manufacturing techniques.

According to the present disclosure, an article of footwear includes an upper and a sole structure that is thermoformed to the upper. The upper has a ground facing surface, and opposing medial and lateral side walls disposed on opposite sides of the ground facing surface. The sole structure has an inner surface adhered to the upper and an outer surface that is opposite the inner surface.

The sole structure includes a thermoplastic base layer that defines the inner surface of the sole structure. The sole structure further includes a thermoplastic outer layer integrally formed with the base layer. The outer layer has a plurality of protuberances, where each protuberance has an outer face that defines a portion of the outer sole surface. The outer layer further includes a plurality of splayed sipes extending across a portion of the sole structure, each splayed sipe generally extends between at least two adjacent protuberances. In some embodiments, one or more of the sipes may extend approximately perpendicular to other sipes. Likewise, in some embodiments, the plurality of protuberences may extend continuously between opposite medial and lateral portions of the sole structure.

In some embodiments, the outer face of each of the plurality of protuberances may comprise a skin having a density that is greater than an average density of the outer layer. In such a design, the protuberance may deform during the thermoforming such that at least a portion of the plurality of protuberances have a base portion with a cross-sectional area that is greater than a cross-sectional area of the respective protuberance at the outer face.

In some embodiments, the sole structure may comprise a first material having a pigment of a first color, and a second material having a pigment of a second color. The first material and second material are integrally molded in a layered, abutting arrangement between the inner surface and the outer surface. In some configurations, the terminus for at least a portion of the plurality of sipes is located within the first material such that the sipe extends through a portion of the first material and entirely through the second material. The first and second materials may both comprise a common polymer, such as ethylene-vinyl acetate.

In an embodiment, a sole structure for an article of footwear may include a thermoplastic base layer that defines an inner surface operative to be secured to a portion of an upper, and further defines a concave recess for receiving a portion of the upper. The inner surface including a central region operative to be secured to a ground facing surface of the upper and opposing sidewalls operative to be secured to opposite medial and lateral side walls of the upper. A thermoplastic outer layer is integrally formed with the base layer and includes a plurality of protuberances and a plurality of splayed sipes. Each protuberance has an outer face that defines a portion of an outer sole surface. Additionally, each splayed sipe extends across a portion of the sole structure and between at least two adjacent protuberances.

In an embodiment, a method of manufacturing an article of footwear includes cutting a plurality of sipes into an outer surface of a pre-formed, foamed thermoplastic sole structure that has both an inner surface and an opposite outer surface. An adhesive is applied to the inner surface of the pre-formed sole structure and the sole structure is heated to permit forming, The heated sole structure is positioned adjacent to a ground-facing surface of a lasted upper, and then is thermoformed against the lasted upper to draw the adhesive into contact with the ground-facing surface of the upper, and such that at least a portion of the pre-formed sole structure bends into contact with a sidewall of the upper.

In general, the thermoforming process may cause the some or all of the plurality of sipes to splay. In some embodiments, thermoforming includes applying a force to the outer surface of the sole structure using a flexible sheet in contact with the outer surface. This force may be applied by creating at least one of a vacuum on a first side of the flexible sheet or a positive pressure on a second side of the sheet.

The method includes molding the pre-formed sole structure through at least one of a compression molding or an injection molding process. In some designs, this may involve molding a first material in an abutting relationship with a second material. Such a multi-material molding process may comprise placing the first material adjacent to the second material within a first mold, and heating the mold such that the first material and second material expand to fill the mold. This may result in the creation of an expanded sole structure. The expanded sole structure may then be removed from the first mold and compression molded into the pre-formed sole structure in a second mold that is smaller than the first mold.

The intermediate sole structure for an article of footwear (i.e., intermediate in the sense that the sole has been substantially constructed, though has not been finally formed to the upper) includes a foamed thermoplastic sole component that comprises both a foamed thermoplastic base layer and a foamed thermoplastic outer layer. These two layers may be integrally formed, though a plurality of sipes may extend through the outer layer and terminate at the base layer. In general, the thermoplastic sole component has an inner surface defined by the base layer, an opposite, outer surface defined by the outer layer, and a thickness defined between the inner surface and the outer surface. In some embodiments, the inner surface is substantially planar and is operative to be adhered to a ground-facing surface of an upper, and the thickness is smaller at a peripheral edge of the sole component than within a central region.

In some embodiments, the thickness of the sole structure at an intermediate region that is located between the peripheral edge and the central region may be greater than at both the peripheral edge and at the central region.

In some embodiments, the sole component may comprise a first material defining at least a portion of the inner surface, and a second material defining at least a portion of the outer surface. The first material and the second material meet at a boundary that is not coincident with a boundary between the base layer and the outer layer. In some embodiments, this material boundary may lie within the outer layer.

In some embodiments, each of the plurality of sipes may extend into the sole component in a common direction that is substantially orthogonal to the inner surface.

The sole component may have a lateral dimension in at least a portion of the sole that is larger than a corresponding lateral dimension of an upper intended to be coupled with the sole structure. A sole component of this type then comprises a lateral portion operative to bend into contact with a lateral sidewall of the upper and a medial portion operative to bend into contact with a medial sidewall of the upper. Furthermore, in some embodiments, the sole component comprises a heel portion that is operative to bend into contact with a heel sidewall of the upper.

"A," "an," "the," "at least one," and "one or more" are used interchangeably to indicate that at least one of the item is present; a plurality of such items may be present unless the context clearly indicates otherwise. All numerical values of parameters (e.g., of quantities of conditions) in this specification, including the appended claims, are to be understood as being modified in all instances by the term "about" whether or not "about" actually appears before the numerical value. "About" indicates that the stated numerical value allows some slight imprecision (with some approach to exactness in the value; about or reasonably close to the value; nearly). In addition, disclosure of ranges includes disclosure of all values and further divided ranges within the entire range. Each value within a range and the endpoints of a range are hereby all disclosed as separate embodiment. The terms "comprises," "comprising," "including," and "having," are inclusive and therefore specify the presence of stated items, but do not preclude the presence of other items. As used in this specification, the term "or" includes any and all combinations of one or more of the listed items. When the terms first, second, third, etc. are used to differentiate various items from each other, these designations are merely for convenience and do not limit the items.

The terms "first," "second," "third," "fourth," and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "include," and "have," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, device, or apparatus that comprises a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such process, method, system, article, device, or apparatus.

Other features and aspects will become apparent by consideration of the following detailed description and accompanying drawings. Before any embodiments of the disclosure are explained in detail, it should be understood that the disclosure is not limited in its application to the details or construction and the arrangement of components as set forth in the following description or as illustrated in the drawings. The disclosure is capable of supporting other embodiments and of being practiced or of being carried out in various ways.

Referring to the drawings, wherein like reference numerals are used to identify like or identical components in the various views, <FIG> schematically illustrates an article of footwear <NUM> that includes an upper <NUM> coupled with a sole structure <NUM>. In the current embodiment, the article of footwear <NUM> is shown in the form of an athletic shoe that may be suitable for walking or running. Concepts associated with the present article of footwear <NUM>, may also be applied to a variety of other athletic footwear types, including but not limited to baseball shoes, basketball shoes, cross-training shoes, cycling shoes, football shoes, soccer shoes, sprinting shoes, tennis shoes, and hiking boots.

As commonly understood, the upper <NUM> is a portion of the article of footwear <NUM> that at least partially defines an interior cavity <NUM> that is adapted to receive a foot of a wearer. The upper <NUM> may include one or more provisions for securing and/or tensioning the upper <NUM> around the foot of the wearer (e.g., laces, straps, buckles, bands, and the like).

As will be discussed in greater detail below, the sole structure <NUM> may be permanently attached to one or more portions of upper <NUM> and may generally extend between the upper <NUM> and the ground (i.e., when the article <NUM> is worn in a typical manner). The sole structure <NUM> may be operative to attenuate ground reaction forces (e.g., cushion the foot), provide traction, enhance stability, and/or influence the motions of the foot.

For reference purposes, article of footwear <NUM> upper <NUM> may be divided generally along a longitudinal axis (heel-to-toe) into three general regions: a forefoot region <NUM>, a midfoot region <NUM>, and a heel region <NUM>. Forefoot region <NUM> generally includes portions of article of footwear <NUM> corresponding with the toes and the joints connecting the metatarsals with the phalanges. Midfoot region <NUM> generally includes portions of article of footwear <NUM> corresponding with an arch area of the foot. Heel region <NUM> generally corresponds with rear portions of the foot, including the calcaneus bone. Article of footwear <NUM> also includes a lateral side <NUM> and a medial side <NUM>, which extend through each of forefoot region <NUM>, midfoot region <NUM>, and heel region <NUM> and correspond with opposite sides of article of footwear <NUM>. More particularly, lateral side <NUM> corresponds with an outside area of the foot (i.e., the surface that faces away from the other foot), and medial side <NUM> corresponds with an inside area of the foot (i.e., the surface that faces toward the other foot). Forefoot region <NUM>, midfoot region <NUM>, heel region <NUM>, lateral side <NUM>, and medial side <NUM> are not intended to demarcate precise areas of article of footwear <NUM>. Rather, forefoot region <NUM>, midfoot region <NUM>, heel region <NUM>, lateral side <NUM>, and medial side <NUM> are intended to represent general areas of article of footwear <NUM> to aid in the following discussion.

When referring to different portions of the article of footwear <NUM> it is also common for aspects to be defined relative to a ground surface upon which the sole structure <NUM> sits when worn on a user's foot in a traditional upright manner. For example, as generally shown in the exploded view provided in <FIG>, the sole structure <NUM> (or various layers or components included in the sole structure <NUM>) may have an upper, or inner surface <NUM> that faces the wearer's foot, and a lower, or outer surface <NUM> that is mostly between the ground and the inner surface <NUM> of the sole <NUM>. Likewise, the upper <NUM> may have a ground-facing surface <NUM> that is generally provided along an underside of the wearer's foot and is in contact with the sole structure <NUM>. In some embodiments, the ground-facing surface <NUM> of the upper <NUM> may be defined by a strobel, however, in a more preferred embodiment, ground-facing surface <NUM> may be integrally and/or seamlessly formed with a lateral sidewall <NUM> and a medial sidewall <NUM> of the upper <NUM>, while omitting the use of a strobel.

An example of an upper construction that may be used with the present article of footwear <NUM> is described in <CIT>. The '<NUM> Application generally describes a knitted upper that has a multi-layer fabric construction that resembles a sock or "bootie. " As described, the upper may have selective reinforcement or stiffening portions within the heel, lateral sidewall <NUM>, and/or medial sidewall <NUM>. These stiffened portions may be provided, for example, by incorporating stiffening panels between adjacent knitted layers, or by thermally treating regionally provided thermoplastic yarns within the knit to alter a material property of the fabric.

The present sole structure <NUM> may accomplish unique geometries by being thermoformed to the upper <NUM> as a final, or near-final step in the manufacturing process. In doing so, sole undercuts and geometries may be created that are impractical and/or cost prohibitive to produce by direct molding (e.g., via injection or compression molding). Furthermore, the present techniques provide for a more custom fit between a sole structure <NUM> and a lasted upper. The present techniques and designs are a departure from conventional sole manufacturing, which typically involves injection or compression molding the sole structure into its final shape.

Referring to the cross-sectional view provided in <FIG>, in one configuration, the sole structure <NUM> may generally comprise a thermoplastic base layer <NUM> that is integrally formed/molded with a thermoplastic outer layer <NUM>. The thermoplastic base layer <NUM> may define the inner surface <NUM> of the sole structure <NUM>, and may provide structure and continuity to the sole structure <NUM>. Conversely, the thermoplastic outer layer <NUM> may define a plurality of protuberances <NUM> that are separated from each other via a plurality of sipes <NUM>. In general, each sipe <NUM> may originate from a terminus <NUM> located on the boundary <NUM> between the thermoplastic base layer <NUM> and the thermoplastic outer layer <NUM>. Said another way, each sipe <NUM> may lie entirely within the thermoplastic outer layer <NUM> (i.e., the termini <NUM> may serve to generally define the boundary <NUM>).

As used herein, a sipe, sipes, and siping is intended to refer to thin cuts in a surface of the sole structure <NUM>. Sipes are typically formed via a secondary process after the foamed sole structure <NUM> is molded. In some embodiments, they may be formed by cutting the sole structure <NUM> to a controlled depth, such as with a hot knife or laser. In general, the width of the cut is limited to the width of the tool used to make the cut.

As further shown in <FIG>, when the sole <NUM> is thermoformed to the upper <NUM>, some or all of the plurality of sipes <NUM> may splay as a result of the bending that occurs in the base layer <NUM>. As will be discussed below, in an embodiment where a flat inner surface <NUM> is molded to a substantially contoured/curved upper <NUM>, a substantial majority of the sipes <NUM> may experience some amount of splaying during the thermoforming process. In general, the thermoforming process involves heating up at least a portion of the foamed thermoplastic, forming it to a surface (e.g., via vacuum forming), and then cooling the thermoplastic to maintain it in the deformed state.

Referring to <FIG>, while the bending of the sole structure <NUM> may cause a plurality of the sipes <NUM> to splay and open up, it may also have an effect on the protuberances <NUM> that are coupled with the bent base layer <NUM>. More particularly, the bending in the base layer <NUM> may impart a tensile stress within a base portion or root <NUM> of the protuberance <NUM>. This tensile stress may then cause a corresponding dimensional expansion in the foam <NUM>. In one configuration, however, an outer face <NUM> of the protuberance <NUM> may comprise a skin <NUM> that resists dimensional expansion to a greater degree than the foam <NUM>. In one embodiment this resisted expansion may result in a dimension <NUM> of the base portion <NUM> of the protuberance <NUM> being greater than a similar dimension <NUM> of (or at) the outer face <NUM>. In an embodiment, the dimension <NUM>, <NUM> may be, for example, a cross-sectional area.

In general, the skin <NUM> may be a byproduct of the molding process used to create the foamed sole structure <NUM>. This skin <NUM> may generally have a density that is greater than an average density of the foamed outer layer, and/or a density that is greater than a density of the directly adjacent foam <NUM>. In effect, this skin <NUM> may provide a toughened outer surface that may be akin to a more traditional outsole surface. The plurality of skinned outer faces <NUM> may collective define some or all of the outer surface <NUM> of the sole structure <NUM>. Furthermore, because the sipes <NUM> are cut after the skin <NUM> has formed, the skin <NUM> only exists on the outer face <NUM> of the protuberance <NUM>, and not on the sidewalls <NUM> of the protuberance <NUM> (i.e., the walls abutting the sipe <NUM>).

<FIG> schematically illustrates an embodiment of a sole structure <NUM> that includes a first plurality of splayed sipes <NUM> extending in a generally longitudinal direction between the forefoot region <NUM> and heel region <NUM>, and a second plurality of splayed sipes <NUM> extending in a generally lateral direction between the lateral side <NUM> and the medial side <NUM> of the sole <NUM>. As shown, each of the first plurality of splayed sipes <NUM> intersects each of the second plurality of splayed sipes <NUM>. It should be noted, that additional sipes may be included, which are not part the first plurality or second plurality of sipes, though may have similar attributes. A design such as shown in <FIG> allows the sole structure <NUM> to achieve a more natural motion response, by reducing any bending restrictions about one or more longitudinal and/or lateral axes.

In an embodiment, the sole pattern illustrated in <FIG> may be carried through onto one or more upwardly extending portions <NUM> of the sole structure <NUM>. These upwardly extending portions are in contact with and adhered to the lateral sidewall <NUM>, the medial sidewall <NUM>, and optionally a heel wall portion <NUM> (shown in <FIG>) of the upper <NUM>. For example, in an embodiment, a first sole portion <NUM> may extend up a portion of the lateral sidewall <NUM> of the upper <NUM> and may include a first plurality of sidewall protuberances <NUM>, such as shown in <FIG>. Similarly, a second sole portion <NUM>, may also extend up a portion of the medial sidewall <NUM> of the upper <NUM>, and may include a second plurality of protuberances (i.e., similar to that shown in <FIG>, though on the opposite side). Additionally, in some embodiments, a sole portion <NUM> may upwardly extend into contact with a heel wall portion <NUM>, such as generally shown in <FIG>, <FIG>, and <FIG>. In any of these upwardly extending portions <NUM>, one or more sipes <NUM> may extend outward from the base layer <NUM> and along the sole structure <NUM> in a substantially longitudinal direction. In an embodiment, these sidewall sipes <NUM> may be oriented such that one or more protuberances <NUM>, <NUM> are positioned between the sipe <NUM> and a ground plane <NUM> (when the shoe is in a neutral, upright position resting on the ground plane such as shown in <FIG>, and "between" contemplates an examination along a datum <NUM> that is normal to the ground plane <NUM> and that intersects the sipe <NUM>).

Traditional molding techniques would have difficulty if attempting to directly mold a sole design such as shown in <FIG>. More particularly, the one or more sidewall sipes <NUM> may present a significant molding undercut problem if such a design was attempted to be molded directly. A molding undercut results when a portion of the mold interferes with a part's ability to be withdrawn from a final mold. In some situations, a small undercut may be tolerable if the material can yield without tearing or plastically deforming when the part is removed from the mold. If the undercut is too large, then additional molding complexities must be used to create the geometry, such as removable slides, or other complex multi-part mold assemblies (which generally prevent bulk manufacture). Presently disclosed designs and techniques overcome this problem by forming the splayed siping voids during a post-molding, thermoforming step (i.e., also used to adhere the sole structure <NUM> to the upper <NUM>) and by not directly molding them into the sole <NUM>.

In some embodiments, the pattern of the plurality of sipes <NUM> extending across the sole structure may be designed to provide certain application-specific benefits. For example, the sole structure <NUM> shown in <FIG> may enable a natural motion foot response that may be similar to training barefoot. Furthermore, because of the splayed sipes on the outer surface, the sole structure <NUM> may further accommodate and allow natural foot expansion (laterally and/or longitudinally) that occurs during and through a ground impact and push off.

<FIG> schematically illustrates another embodiment of a sole structure <NUM>. This design generally includes a plurality of sipes <NUM> that each extend between a lateral side <NUM> and a medial side <NUM> of the sole structure <NUM>. Each sipe <NUM> may incorporate a longitudinal deflection component <NUM> within a central region <NUM> of the sipe <NUM> that, to varying degrees, resembles a "U" or "V. " Such a design may provide increased edge stability by not including any longitudinal siping (or sipes with a dominant longitudinal component) near the lateral or medial edge portions <NUM>, <NUM>. Conversely, the longitudinal deflection component <NUM> within the central region <NUM> may permit foot roll and/or lateral foot expansion through a ground impact.

In some embodiments, the flexibility of the sole structure <NUM> may be further increased by incorporating or cutting one or more sipes <NUM> into the inner surface <NUM> of the sole structure <NUM>, such as shown in <FIG>. To ensure that the sole <NUM> remains waterproof and/or provides adequate protection against foreign objects on the ground, it is preferable for any sipes <NUM> cut into the inner surface <NUM> to not intersect with any sipes <NUM> cut into the outer surface <NUM>. Doing so would result in a potential hole or opening extending entirely through the sole structure <NUM>. As shown in <FIG>, in one configuration, the sipes <NUM> cut into the inner surface <NUM> may be staggered along a longitudinal axis relative to the sipes <NUM> cut into the outer surface <NUM>.

While <FIG> and <FIG> illustrate two potential siping patterns, other patterns and unique geometries are similarly possible. For example, in an embodiment, the sole structure <NUM> may include a plurality of sipes that all extend in a substantially longitudinal direction. In another embodiment, the sipes may extend diagonally from each of the medial and lateral edges. In a variation, these sipes may terminate prior to reaching the opposite edge.

The current sole construction techniques may be used to create differing sole geometries that, for example, provide a better natural motion response and/or customized stiffness properties (e.g., lateral, edge, longitudinal, roll, flex, impact, etc.). Additionally, by exposing interior foam via the plurality of splayed sipes <NUM>, the current sole construction techniques may also be used to create unique visual characteristics or other dimensional properties that may be extraordinarily difficult and/or impossible to create through traditional molding practices. More specifically, in one configuration, the sole structure <NUM> may be formed from a plurality of different materials that may be co-molded prior to cutting the plurality of sipes <NUM> and thermoforming to the upper <NUM>.

<FIG> schematically illustrates a cross-sectional view, similar to <FIG>, which more clearly illustrates a plurality of different materials being used to form the sole structure <NUM>. As shown, a first material <NUM> and a second material <NUM> may be integrally molded in a layered, abutting arrangement between the inner surface <NUM> and the outer surface <NUM>. In one configuration, the terminus <NUM> for each of a plurality of sipes <NUM> may be located within the first material <NUM> such that the sipe extends through a portion of the first material <NUM> and further extends entirely through the second material <NUM>. In doing so, the present design may provide a plurality of the protuberances <NUM> with a layered, multi-material construction. The extent and relative proportion of the materials <NUM>, <NUM> within each protuberance may be controlled, for example, by varying the sole thickness <NUM> and/or the depth <NUM> of each sipe <NUM>. While two materials are shown in <FIG>, in other embodiments, the multi material construction may include three or more materials, or may vary in number across the sole structure <NUM>.

In one configuration, each of the first material <NUM> and second material <NUM> may comprise a foamed polymer having a different density or hardness. For example, in an embodiment, the second material <NUM> may be comparatively softer and/or less dense then the first material <NUM>. In such a design, each protuberance would still have relative root stability, provided by the harder, more dense inner material, while still maintaining an initial impact cushioning response via the softer material. In another embodiment, the ground-contacting second material <NUM> may be harder and/or more dense than the inner, first material <NUM> to provide improved resiliency and wear resistance. In still another embodiment, the inner, first material <NUM> (containing the terminus <NUM> and root portion <NUM> of the protuberances <NUM>) and the outer, ground-contacting material <NUM> may be formed from comparatively harder and/or more dense materials (for the reasons stated above), and a third material may be disposed between the first material <NUM> and the second material <NUM>, which may be comparatively softer than the first and second materials <NUM>, <NUM> to provide an improved cushioning response.

In another configuration, the first material <NUM> and the second material <NUM> may be substantially similar in composition, except for the nature or composition of one or more pigments that are incorporated with the respective material. As mentioned above, the ability for the present sole structure <NUM> to expose internal sole materials, even while in a resting state, may provide a unique ability to vary the outwardly visible coloration and styling of the sole structure <NUM> through the use of color breaks or divisions <NUM> within each protuberance by altering the foam or foam layers used to form that protuberance. Finally, in an embodiment, both the material properties/hardnesses and the pigmentation/coloration of the first material <NUM> and the second material <NUM> may be different.

<FIG> schematically illustrates a method <NUM> of manufacturing an article footwear <NUM> similar to what is shown in <FIG>. This method <NUM> generally begins by receiving, or molding a foamed thermoplastic sole structure at <NUM>, and by receiving and/or constructing a lasted upper at <NUM>. As discussed above, the lasted upper may be constructed by pulling one or more layers of tubular knit material onto a last, and then closing a toe seam, for example, using RF or ultrasonic welding techniques. In one configuration, the tubular knit material may include a plurality of thermoplastic fibers and one or more adjacent layers may at least partially fuse together and/or establish a neutral shape defined by the last, for example during a heat treating or thermoforming process applied to the upper <NUM>. Likewise, in some embodiments, the tubular knit material may include one or more stiffening panels, or other features typical of a shoe, such as lace eyelets graphical embellishments, and the like. Further detail on the process for forming a strobel-less upper are explained in the '<NUM> Application mentioned above. While a strobel-less upper is preferred, in other embodiments, the upper <NUM> may be constructed in a standard manner by seaming a vamp an/or other shoe portions to a strobel.

In general, molding a foamed thermoplastic sole structure at <NUM> may involve converting a raw polymeric material, together with one or more plasticizers, blowing agents, pigments, or the like, into a foamed sole structure <NUM> using a heated and/or pressurized mold. The manner of manufacturing the sole structure <NUM> may include any one of: direct injection molding, injection molding a preform followed by compression molding the preform into a final shape, compression molding a preform from a bulk polymer and then compression molding the preform into a final shape, direct compression molding, or the like.

The materials used to form the sole structure <NUM> may generally include phylon (ethylene vinyl acetate or "EVA") and/or polyurethane ("PU") base resins. If EVA is used, it may have a vinyl acetate (VA) level between approximately <NUM>% and approximately <NUM>%. Suitable EVA resins include Elvax®, provided by E. du Pont de Nemours and Company, and Engage™, provided by the Dow Chemical Company, for example. In certain embodiments, the EVA may be formed of a combination of high melt index and low melt index material. For example, the EVA may have a melt index of from about <NUM> to about <NUM>.

The EVA resin may be compounded to include various components including a blowing agent and a curing/crosslinking agent. The blowing agent may have a percent weight between approximately <NUM>% and approximately <NUM>%. The blowing agent is thermally decomposable and is selected from ordinary organic and inorganic chemical blowing agents. The nature of the blowing agent is not particular limited as long as it decomposes under the temperature conditions used in incorporating the foam into the virgin resin. Suitable blowing agents include azodicarboamide, for example.

In certain embodiments, a peroxide-based curing agent, such as dicumyl peroxide may be used. The amount of curing agent may be between approximately <NUM>% and approximately <NUM>%. The EVA may also include homogenizing agents, process aids, and waxes. For example, a mixture of light aliphatic hydrocarbons such as Struktol® 60NS, available from Schill+Seilacher "Struktol" GmbH, may be included to permit other materials or scrap EVA to be more easily incorporated into the resin. The EVA may also include other constituents such as a release agent (e.g., stearic acid), activators (e.g., zinc oxide), fillers (e.g., magnesium carbonate), pigments, and clays.

In embodiments that incorporate multiple materials, such as shown in <FIG>, each material <NUM>, <NUM> may be formed from a material that is compatible and readily bonds with the other material. For example, both materials <NUM>, <NUM> may be formed from an EVA resin with suitable blowing agents, crosslinking agents, and other ancillary components, pigments, fillers, and the like. Other suitable materials for the first material <NUM> and the second material <NUM> will become readily apparent to those skilled in the art, given the benefit of this disclosure.

As noted above, the first material <NUM> may be formed of a material having a first color, while the second material <NUM> may be formed of a material having a second color that is different than the first color. First and second materials <NUM>, <NUM> may also have different values for various physical properties, even if formed from the same base resin, in order to alter or enhance the performance characteristics of the footwear. For example, first and second materials <NUM>, <NUM> may have different hardnesses, densities, specific gravities, or any other beneficial physical property. Other suitable physical properties for which the first and second portions may have different values will become readily apparent to those skilled in the art, given the benefit of this disclosure.

As seen in <FIG>, a color line or boundary <NUM> is formed at the boundary or interface between the first material <NUM> and the second material <NUM> of sole structure <NUM>. It is desirable to minimize the bleeding between the two different colors of the first material <NUM> and the second material <NUM>, which can occur during the molding process. It is to be appreciated that the aesthetics of sole structure <NUM> are improved by minimizing bleeding during the manufacture of sole structure <NUM>. Techniques to minimize bleeding, including the use of one or more peripheral molding flanges, are discussed in U. Patent Application Pub. It should further be appreciated that more than two portions/materials can be used to form the sole structure, which may introduce additional colors and additional performance characteristics to sole structure <NUM>.

In one method of molding a multi-material sole structure <NUM> such as shown in <FIG>, a first preform and a second preform may be formed to a general shape that is similar to the final desired shape (though not to final dimensions). In one embodiment, each preform may directly correspond to a different one of the first material <NUM> and second material <NUM>, and may be created, for example, through injection or compression molding.

The first and second preforms may then be placed in an intermediate mold together, so that the first preform is in contact with the second preform. Heat is then supplied to the mold for a predetermined period of time. In one embodiment, the mold may be heated at a temperature of approximately <NUM>° C. for approximately <NUM>-<NUM> minutes. This heating may cause first and second preforms to partially expand and fill the internal mold cavity and spill into any coupled molding overflow chambers. It is to be appreciated that the specific temperature and time period used to form the sole structure preform in the mold can be varied, in known fashion, depending on the particular EVA, or other material, used. After this heating step is complete, the mold is opened, and the sole structure preform may further expand in a known fashion after it is removed from the mold.

After the sole structure preform has stabilized and cooled to ambient temperature, the sole structure preform then may undergo a subsequent compression molding step in a second mold. This second mold may have an internal volume that is less than a volume of the cooled sole structure preform. Thus, when the preform is compression molded, it may be physically compressed to a smaller volume when the mold is closed. The second mold may then be heated for a predetermined period of time. In certain embodiments, the second mold may be heated to approximately <NUM>° C. for approximately <NUM> minutes, thereby forming a sole structure of the desired size/shape. The specific temperatures and time periods used to heat the second mold can be varied, in known fashion, depending on the particular EVA, or other material, used.

While the second mold is still closed, it is cooled, allowing sole structure to fully cure and stabilize. In certain embodiments, the second mold is cooled in a closed condition for approximately <NUM> minutes until the temperature of second mold is below approximately <NUM>° C. Following this, the mold may be opened and the sole structure removed.

Once the sole structure has been molded in step <NUM>, a plurality of sipes may be cut into the outer surface <NUM> (at <NUM>) and optionally cut into the inner surface (at <NUM>). The plurality of sipes <NUM> may be cut, for example, using a blade, which may be heated to aid in creating a smooth cut with an acceptable surface finish on the sidewalls of the sipe. In another embodiment, one or more of the plurality of sipes <NUM> may be laser cut into the foam to a controlled depth. In some embodiments, each of the plurality of sipes may be cut to varying depths, dependent on the sole thickness, cushioning design objectives, and desired final sole appearance. In some embodiments, the stiffness and/or cushioning properties of any one or more protuberances (or of the sole in that local area) may be altered to meet different design objectives by varying the depth of the adjacent sipes (i.e., where deeper sipes may provide a less stiff sole structure with increased cushioning). If sipes are cut into the inner surface <NUM>, it is preferable that they do not intersect with the sipes cut into the outer surface <NUM>. In some embodiments, the sipes may all be cut in an orthogonal direction relative to the inner surface <NUM>.

In one embodiment, the sipes may be cut such that they all extend into the outer surface <NUM> from a common direction. Such a design may increase manufacturing efficiency by eliminating any need to reorient a cutting tool for each sipe or each portion of a sipe. In an embodiment where the inner surface <NUM> is substantially flat/plannar, this common cutting direction may be orthogonal to the inner surface <NUM>. In another embodiment, one or more of the sipes maybe at an oblique angle relative to the inner surface <NUM>. Making such an oblique cut may enable unique geometries to be created when the sole is thermoformed to the upper.

Once the sole has been siped in steps <NUM> and <NUM>, an adhesive may be applied to the inner surface <NUM> of the sole structure <NUM> at <NUM>. The adhesive may be applied, for example, using a brush, spray, or roller applicator. To minimize any required complexity, the roller applicator may be best suited for applications where the inner surface <NUM> is substantially flat. In such a configuration, the roller <NUM> may be a single roller with a constant cylindrical cross-section, such as shown in <FIG>, and the sole structure <NUM> may be cradled within a fixture <NUM> that resembles a lower mold. As an additional benefit of rolling, if any sipes are cut into the inner surface <NUM>, such as shown in <FIG>, then the roller applicator could most easily be controlled to avoid applying adhesive within the inner/upper sipes, and without the need to separately mask the sipes. In such an embodiment, the unadhered inner sipes may permit each sipe to serve as an expansion gap that may permit purely in-plane stretch and/or flexure of the sole. When combined with a strobel-less upper, such a stretch or flexure response may be even further unrestrained (i.e., where strobels are typically more restrictive than a strobel-less, all-knit upper would be).

Following the application of the adhesive at <NUM>, the sole structure <NUM> may be heated to soften the thermoplastic foam (at <NUM>), and particularly at least the thermoplastic base layer <NUM>. As further shown in <FIG>, in an embodiment, the heating may be performed by a radiant heating element <NUM> or convective heating nozzles (not shown) that apply thermal energy to only the inner surface <NUM> of the sole structure <NUM>. As the outer layer <NUM> has already been siped through, the primary purpose of the heating is to soften the base layer <NUM> only to a point where it can be thermoformed to the upper. If the sole structure <NUM> is heated too much, then it may lose some structural integrity and/or its properties may change to an undesirable degree. As such, in a preferred embodiment, a temperature gradient should exist between the inner surface <NUM> and the outer surface <NUM>. In one configuration, the fixture <NUM> upon which the sole structure <NUM> rests may serve as a heatsink to cool the outer layer <NUM> while the base layer <NUM> is being heated. Doing so may ensure that the outer layer <NUM> does not deform in any unintended ways while being thermoformed.

Referring again to <FIG>, once the base layer <NUM> is softened to a point where it may be thermoformed (at <NUM>), it may then be positioned adjacent to the ground-facing surface <NUM> of an upper <NUM> provided on a last <NUM> (at <NUM>), such as shown in <FIG>. Once in this position, the sole structure <NUM> may be urged into contact with the upper, such as by vacuum forming (at <NUM> - in <FIG>), where it may then be cooled (at <NUM>) to retain its formed shape.

During the forming step <NUM>, the softened sole structure <NUM> may be drawn into contact with the lasted upper <NUM>, such as through the use of positive external pressure, negative internal pressure, compliant fixturing, or the like. In vacuum forming, the lasted upper <NUM> and sole structure <NUM> may be placed in their predefined arrangement under a compliant polymeric sheet. Once in position, a vacuum may be created under the sheet such that the sheet exerts a force against the sole structure <NUM> to urge it into contact with the upper <NUM>. In doing so, the adhesive may be drawn into contact with the ground-facing surface of the upper and at least a portion of the pre-formed may bend into contact with a sidewall of the upper, such as shown in <FIG>. The bending caused by the vacuum forming then causes the plurality of sipes to splay.

<FIG> schematically illustrate an embodiment of an intermediate sole structure <NUM> that may be used to create the final sole structure of <FIG>. The intermediate sole structure <NUM> (generally, sole structure <NUM>) is generally of the form that follows the siping of step <NUM>, shown in <FIG>. As shown, the sole structure <NUM> has an outer surface <NUM> and an inner or inner surface <NUM> that is operative to be directly adhered to the upper <NUM>. This intermediate sole structure <NUM> includes a plurality of sipes <NUM> extending inward from the outer surface <NUM>, though are not yet splayed. As shown in <FIG>, based on the desired final geometry and required stability and/or cushioning across the sole, each sipe <NUM> may be cut to a different depth relative to the outer surface <NUM>. Each sipe <NUM> may have a terminus <NUM>, and the plurality of termini <NUM> may define a boundary <NUM> between the base layer <NUM> and the outer layer <NUM>.

In the embodiment illustrated in <FIG> the inner surface <NUM> may be substantially flat/planar. Conversely, the outer surface <NUM> may be substantially contoured while tapering to the inner surface <NUM> around a periphery <NUM> of the sole structure <NUM>. In some embodiments, the thickness of the sole structure <NUM> may vary in an effort to control both the final design, including the amount of splay, and to control a cushioning response, stability, and traction of the final sole structure <NUM>. For example, in one configuration, in an effort to promote uniform ground contact in the final sole structure the heel region <NUM> of the pre-form sole structure <NUM> may be dimensioned such that a sole thickness <NUM> within a center region <NUM> is greater than a sole thickness <NUM> at the periphery. Additionally, a sole thickness <NUM> taken within an intermediate region <NUM> between the center region <NUM> and the periphery <NUM> may be greater than both of the other two thicknesses <NUM>, <NUM>. In doing so, the final sole structure <NUM> may have a more flat ground contacting surface, as the center region <NUM> may end up protruding outward slightly while the intermediate region <NUM> may be drawn inward slightly and/or otherwise thinned due to the bending and Poisson's ratio of the material.

Similar to the sole <NUM> shown in <FIG>, the sole in <FIG> includes a multi material construction, whereby both a first material <NUM> and a second material <NUM> cooperate to form the inner surface <NUM> while the outer surface <NUM> is generally formed from only the second material <NUM>. While the figures show a two-material construction, it may be equally possible to include additional materials that may form a portion of the outer surface <NUM>, and/or of an interior region of the sole structure <NUM>. As shown in <FIG>, in some configurations, at least a majority of the sipes <NUM> may extend entirely through the second material <NUM>. In doing so, once the sipes <NUM> are splayed, multiple materials may be exposed, and may provide unique visual effects.

In some embodiments, such as shown in <FIG>, a sole structure <NUM> of the present construction may include a rigid or semi rigid plate <NUM> that is operatively configured to inhibit bending or certain flexural motions of the sole structure <NUM> once fully assembled. In one configuration, the plate <NUM> may be a polymeric structure that may have a substantially greater stiffness than the abutting/surrounding foam sole. The polymeric plate <NUM> may be formed from, for example, a polyamide (e.g., PA6 or PA66), polyether ether ketone (PEEK), Polyphenylene sulfide (PPS), Polytetrafluoroethylene (PTFE), and/or the like. In some embodiments, the plate <NUM> may be a composite structure, where a plurality of continuous or discontinuous reinforcing fibers are embedded therein. In one configuration, the plurality of fibers include carbon, aramid, or glass fibers. In one configuration, the fibers may be short fibers, each having an average longitudinal/length dimension of less than about <NUM>, or less than about <NUM>, or less than about <NUM>, or even less than about <NUM>. These short fibers may be mixed with the molten polymer and injection molded into the required shape. As such, shorter fibers are typically easier to injection mold, though are typically less strong than comparable longer fibers (greater than about <NUM>). In another embodiment, the reinforcing fibers may be continuous fibers that each extend across the plate/structure. In such an example, the fibers may resemble a fabric that is embedded in a polymeric matrix.

The plate <NUM> may be operative to provide structure and stability to the foam sole <NUM>, which may be desirable and/or required during certain sporting activities. In one embodiment, the plate <NUM> may be located only in the forefoot portion <NUM>, or only within the forefoot portion <NUM> and the midfoot portion <NUM>. In other embodiments, the plate may only be located in the midfoot portion <NUM>. In one configuration, the plate <NUM> may be fully embedded within the foam <NUM> used to form the sole structure <NUM>. In one embodiment, the plate <NUM> from <FIG> may be incorporated into a multi-material design, such as shown in <FIG>. In such an embodiment, the plate may be disposed within the outer material <NUM>, or between the harder outer material <NUM> and the softer inner material <NUM> (i.e. to still enable the softer material to attenuate impact forces.

In one configuration, the plate <NUM> may be encapsulated within the foamed sole structure during the molding process used to create the sole. For example, in one configuration, the plate <NUM> may be placed between two pre-foamed or post foamed blanks within a mold. The mold may be closed and heated, thus causing the blanks to fuse together and trap the plate between. In some embodiments, the plate may include a polymeric resin component that is readily bondable the foam. More specifically, similar types of materials are known to bond very easily to each other, even without the use of surface pre-treatments, primers, or physical abrasion. Conversely, some polymers have extremely low bonding affinity for other polymers. Therefore, to promote a healthy bond between the plate and the surrounding foam, in one configuration, the plate and foam may have at least one polymeric component within their formula that is common between them. In this manner, a good surface bond is encouraged.

The use of an embedded rigid or semi rigid plate <NUM> may further permit the sole structure to maintain a more flat-bottom type of final construction when formed into an article of footwear. This result is attributable to the vacuum forming process, where the sides would be drawn inward toward the upper. The plate <NUM> would prevent the under-foot portion <NUM> of the sole structure from taking as pronounced of a curvature as it would in a design without the plate (i.e., it would create a more definite bend-point at the outward edge of the plate while resisting curvature across the width of the plate <NUM>).

Claim 1:
A method of manufacturing an article of footwear comprising:
molding a pre-formed sole structure (<NUM>) through at least one of a compression molding or an injection molding process, the pre-formed sole structure (<NUM>) having a thermoplastic sole component that comprises both a foamed thermoplastic base layer (<NUM>) and a foamed thermoplastic outer layer (<NUM>) and the sole component comprises a medial portion and a lateral portion;
applying an adhesive to the inner surface (<NUM>) of the pre-formed sole structure (<NUM>);
heating the pre-formed sole structure (<NUM>);
positioning the heated, pre-formed sole structure (<NUM>) adjacent to a lasted upper (<NUM>) having a ground-facing underfoot portion, a medial sidewall (<NUM>) and a lateral sidewall (<NUM>), wherein positioning includes aligning the sole portion of the sole structure (<NUM>) in adjacent contact with the ground facing surface of the upper (<NUM>);
thermoforming the pre-formed sole structure (<NUM>) against the lasted upper (<NUM>) such that the adhesive is drawn into contact with the ground-facing surface of the upper (<NUM>), the medial portion of the sole component bends from apart the upper (<NUM>) into contact with the medial sidewall (<NUM>) of the upper (<NUM>), and further such that the lateral portion of the sole component bends from apart the upper into contact with the lateral sidewall of the upper (<NUM>).