Patent Description:
The upper of the article of footwear generally extends over the instep and toe areas of the foot, along the medial and lateral sides of the foot, and around the heel area of the foot. An ankle opening in a heel area generally provides access to the void in the interior of the upper. A lacing system is often incorporated into the upper to adjust the fit of the upper, thereby facilitating entry and removal of the foot from the void within the upper. The upper may include a tongue that extends under the lacing system to enhance adjustability of the footwear, and the upper may incorporate a heel counter to limit movement of the heel. <CIT> discloses a sock with zones of varying numbers of layers. The sock is formed as a single tube on a circular knitting machine. At least one end of the tube is doubled back over a portion of the remainder of the tube to form a double layer first zone.

The objective technical problem to be solved may be considered to overcome or at least to reduce the disadvantages according to the prior art. The problem is solved by the subject matter of the independent claims. One aspect of the present disclosure provides an article of footwear according to the subject matter of claim <NUM>.

In some embodiments, the first layer and the second layer may be formed on a circular knitting machine, and the second layer may be inverted with respect to the first layer. A seam may be formed at least in the second layer in a toe region of the knitted component. The seam may join the first layer to the second layer. A tension force of the second layer may retain the component in an underfoot area of the interstitial space. The interstitial space may be substantially free of adhesive. The component may be a midsole. The knitted component may further include a retention system formed in the second layer, the retention system having a plurality of first yarns and a plurality of second yarns, where the first yarns and the second yarns at least partially form the second layer of the knitted component, where the second yarns bias the retention system to a first state, and where the retention system exerts a tension force in a second state.

In another aspect, the present disclosure provides an upper according to the subject matter of claim <NUM>.

In some embodiments, the component may have a rigidity greater than the first layer and the second layer. The component may have a shape of a bootie that is coextensive with at least a forefoot region and a midfoot region of the upper. The bootie may be coextensive with a portion of a heel region. The component may have a greater stretch resistance than the first layer and the second layer. The first layer and the second layer may be formed by a knitted component. A pocket may be disposed between the first layer and the second layer, where the pocket receives the component. A seam that joins the first layer to the second layer in a toe region of the upper may be included.

Background knowledge useful for understanding the invention relates to a method of making an article of footwear. The method may include pulling an open toe region of an element towards a main fold line disposed between a first portion of the element and a second portion of the element so that an interior surface of the first portion of the element is exposed during the pulling operation, pulling the open toe region past the main fold line and onto the second portion so that the first portion substantially surrounds the second portion and a fold is formed in an ankle region of the article of footwear, aligning the open toe region of the element with a closed toe region of the second portion of the element, and forming a seam to join the open toe region with the closed toe region.

In some embodiments, the element may be a knitted component, and the method may further include forming the knitted component on a knitting machine. An interstitial space may be formed between the first portion and the second portion. The method may further include inserting a component between the first portion and the second portion in the interstitial space.

Background knowledge useful for understanding the invention relates to a knitted component with a knitted layer at least partially formed with a plurality of first yarns and a retention system formed in the knitted layer. The retention system may include a plurality of floating portions of the first yarns, where the retention system is movable from a first state to a second state. In the first state, the floating portions of the first yarns may assume a slack state where a float length of the first yarns is greater than a dimension of the retention system.

In some embodiments, in the second state, the floating portions of the first yarns may be substantially taut. The first yarns may experience a tension force when the retention system is in the second state. The retention system may further include a plurality of second yarns, where the second yarns have an elasticity that is greater than an elasticity of the first yarns. The second yarns may be substantially taut when the retention system is in the first state and when the retention system is in the second state. The retention system may further include a plurality of third yarns at least partially forming the knitted layer, where a plurality of knit structures formed by the third yarns cover an exterior surface of the first yarns. Optionally, a first retention zone may be separated from a second retention zone by a portion of the knitted layer, and the portion of the knitted layer may include stitches formed by the first yarns. The knitted layer may at least partially surround an inner layer and the inner layer may define a void, where the knitted layer forms an outer surface on an overfoot portion and an underfoot portion of the knitted component, and where a portion of the inner layer is continuous with a portion of the knitted layer in an ankle region of the knitted component. The knitted component may include an interstitial space formed between the inner layer and the knitted layer and a component may be disposed between the inner layer and the knitted layer.

Background knowledge useful for understanding the invention relates to an article of footwear which may include a knitted component with a retention system, the retention system including a plurality of first yarns. Each of the first yarns may include a first floating portion located in a first zone of the knitted component, the first zone located on at least one of a medial side and a lateral side of the article of footwear. The retention system may be movable from a first state to a second state, where in the first state, the floating portions of the first yarns have slack.

In some embodiments, the retention system further includes a plurality of second yarns located in the first zone that bias the retention system toward the first state. The retention system may further include a plurality of third yarns at least partially covering the first floating portions of the first yarns. Each of the first yarns may include a second floating portion located in a second zone of the knitted component, the second zone separated from the first zone by stitches formed by the first yarns. The first floating portions may experience a tension force in the second state. The first floating portions may have an orientation approximately perpendicular to a sole structure. In the first state, the knitted component may assume a limp state. The retention system may be formed on a circular knitting machine.

Background knowledge useful for understanding the invention relates to a method of knitting a knitted component. The method may include forming a knitted layer at least partially from a plurality of first yarns and forming a plurality of floating portions of the first yarns in a retention zone, the retention zone including a plurality of second yarn. The retention zone may be movable from a first state to a second state, where the floating portions of the first yarns have slack in the first state, and where the second yarns bias the retention zone to the first state.

In some embodiments, forming the plurality of floating portions of the first yarns may include forming the plurality of floating portions at least partially on a circular knitting machine. The method may additionally or alternatively include forming a plurality of third yarns in the retention zone, wherein the third yarns at least partially overlap the first yarns.

The embodiments of the present disclosure can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the certain principles.

Referring to <FIG>, a first embodiment of an article, such as an article of footwear <NUM> is shown. Article of footwear <NUM> includes an embodiment of an upper <NUM> with a component sandwiched between two layers and an optional sole structure <NUM>. Article of footwear <NUM> is disclosed as having a general configuration suitable for walking or running. Concepts associated with the footwear, including upper <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. The concepts may also be applied to footwear types that are generally considered to be non-athletic, including dress shoes, loafers, sandals, and work boots. The concepts disclosed herein apply, therefore, to a wide variety of footwear types. Furthermore, the concepts disclosed herein may apply to articles beyond footwear, such as accessories or apparel.

In the embodiment of <FIG>, upper <NUM> generally provides a comfortable and secure covering for the foot. The upper <NUM> may include an overfoot area <NUM> and an optional underfoot area <NUM> surrounding a void <NUM>. As such, the foot of a wearer may be located within a void <NUM> to effectively secure the foot within article of footwear <NUM> or otherwise unite the foot and article of footwear <NUM>. Moreover, sole structure <NUM> may be secured to a lower area (e.g., the underfoot area <NUM>) of upper <NUM> or may partially or completely reside within a portion of the upper <NUM> such as an interstitial space as described below, and may be positioned between the foot and the ground 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.

In some embodiments, sole structure <NUM> may generally include a midsole <NUM> and/or an outsole <NUM>. A midsole <NUM> may be secured to a lower surface of upper <NUM>, or may be positioned within an interstitial space <NUM> between an outer knit layer <NUM> and an inner knit layer <NUM>, as described below. When midsole <NUM> occupies the interstitial space <NUM>, tension in the outer knit layer <NUM> may retain midsole <NUM> in an underfoot position between the inner knit layer <NUM> and outer knit layer <NUM>. The midsole <NUM> may reside within the interstitial space <NUM> with or without additional elements to retain the midsole <NUM> in the underfoot area, for example adhesives, stitches, heat bonding, RF welding, or sonic welding. The absence of adhesives retaining midsole <NUM> within the interstitial space <NUM> may advantageously contribute to more compliant and reactive on-foot feel. However, outsole <NUM> may be additionally or alternatively be secured to the lower surface of upper <NUM> with the use of an adhesive or other suitable mechanical or chemical mechanisms or means. Midsole <NUM> may be formed from a compressible polymer foam element (e.g., a polyurethane or ethylvinylacetate foam) that attenuates ground reaction forces (e.g., provides cushioning) when compressed between the foot and the ground during walking, running, or other ambulatory activities. Additionally or alternatively, midsole <NUM> may incorporate plates, moderators, fluid-filled chambers, lasting elements, and/or motion control members that further attenuate forces, enhance stability, or influence the motions of the foot.

An outsole <NUM> having a ground-engaging surface can be disposed at a lower surface of midsole <NUM> or a lower surface of upper <NUM> in some embodiments. The outsole <NUM> may be at least partially formed with a textured wear-resistant rubber material, thus providing a tread element <NUM> to impart traction.

Although the depicted configuration of sole structure <NUM> provides an example of a sole structure that may be used in connection with upper <NUM>, a variety of other configurations for sole structure <NUM> may alternatively be used. In some embodiments, for example, an external sole structure <NUM> may be omitted, and portions of upper <NUM> may be treated or otherwise configured to provide a suitable ground-engaging surface.

As depicted, upper <NUM> includes a first or outer knit layer <NUM> and a second or inner knit layer <NUM>. In some embodiments, outer knit layer <NUM> substantially surrounds inner knit layer <NUM>, and outer knit layer <NUM> may form an exterior surface <NUM> (shown in <FIG>) of upper <NUM>. In some embodiments, such as shown in <FIG>, outer knit layer <NUM> entirely covers inner knit layer <NUM> so that inner knit layer <NUM> is not visible from an exterior perspective after assembly. In other embodiment, outer knit layer <NUM> covers only a portion of inner knit layer <NUM> so that another portion of inner knit layer <NUM> is visible after assembly from the exterior perspective.

Outer knit layer <NUM> and inner knit layer <NUM> are arranged or otherwise configured in some embodiments to create an interstitial space <NUM> (e.g., a gap) between outer knit layer <NUM> and inner knit layer <NUM>. One or more component(s) <NUM> may be positioned in interstitial space <NUM> between outer layer <NUM> and inner layer <NUM>. Component <NUM> may be a bootie, midsole, cleat plate, a water-resistant membrane, or any other suitable device. Thus as shown in <FIG>, a three-layer upper may be provided with an outer knit layer <NUM>, an inner knit layer <NUM>, and the component <NUM> positioned between outer knit layer <NUM> and inner knit layer <NUM>.

In some embodiments, the component <NUM> disposed in interstitial space <NUM> may be structured or otherwise configured to provide a specific shape to upper <NUM> such that the upper <NUM> is able to hold a specific shape when a foot is not disposed within upper <NUM> (e.g., when the other layers of upper <NUM> lack the structural characteristics to hold a desirable three-dimensional shape on their own). For example, in some embodiments, such as the embodiment shown in <FIG>, the component <NUM> may advantageously facilitate the article of footwear retaining a shape typical of athletic footwear with or without receipt of a foot within the void.

In some embodiments, such as the embodiment shown in <FIG>, the component <NUM> is a bootie. Component <NUM>, as shown best in <FIG>, may have the general configuration of an athletic upper. Component <NUM> may be configured (e.g., sized and shaped) to receive and/or substantially cover a foot of a user when the foot is inserted into upper <NUM>. Component <NUM> may be made of a material that has sufficient rigidity and/or stiffness to maintain its established three-dimensional shape, and may include a material that is more rigid or stiff than the outer knit layer <NUM> and the inner knit layer <NUM>. In some embodiments, component <NUM> may be a single layer of material. Additionally or alternatively, component <NUM> may be made from a nonwoven textile (and it is noted that a knitted textile is distinct from a nonwoven textile). In some embodiments, component <NUM> may include thermoplastic or thermoset portions so that component <NUM> may be heat set to hold a specific shape.

In some embodiments, such as the embodiment shown in <FIG>, component <NUM> is a midsole <NUM> positioned within interstitial space <NUM>. Tension in outer layer <NUM> may retain midsole <NUM> in an underfoot position between inner layer <NUM> and outer layer <NUM>, for example. Midsole <NUM> may reside within interstitial space <NUM> with or without additional elements to retain midsole <NUM> in the underfoot area, for example adhesives or stitches. In embodiments where the midsole <NUM> resides within the interstitial space <NUM> without additional elements securing it to the outer or inner knit layers <NUM>, <NUM>, the midsole <NUM> may better conform to a wearer's foot during ambulatory activities due to the elimination of at least one flexibility-reducing adhesive layer. Additionally, the elimination of adhesive may advantageously reduce the need for certain materials and/or manufacturing steps, which may increase manufacturing efficiency and lower the overall cost of the article of footwear. As described above, midsole <NUM> may be formed from one or more materials that provide cushioning when compressed between the foot and the ground during walking, running, or other ambulatory activities. Midsole <NUM> may also (or alternatively) incorporate other elements that further attenuate forces, enhance stability, or influence the motions of the foot.

Component <NUM> may be made of multiple layers of material. Optionally, component <NUM> may include provisions for cushioning, such as relatively thick portions, inflatable portions, foam portions, or the like. Additionally or alternatively, component <NUM> may include provisions for protection, such as thicker portions, rigid portions such as plates, stiffened portions, or the like. In some embodiments, component <NUM> may have apertures or may otherwise include discontinuities so that component <NUM> essentially provides a scaffold that establishes the three-dimensional shape while retaining breathability and flexibility.

As shown in <FIG>, component <NUM> may establish the shape of an interior void <NUM>, which is the opening within upper <NUM> into which a foot of a user is inserted for use. An interior surface <NUM> of inner knit layer <NUM> may define and form a surface of interior void <NUM>. When inner knit layer <NUM> is formed of a relatively flexible knit, inner knit layer <NUM> may have difficulty in maintaining a specific, three-dimensional shape such as the shape shown in <FIG>. Thus, component <NUM> may communicate with the inner knit layer <NUM> to established and retain a suitable shape of interior void <NUM>.

Component <NUM> may be coextensive with outer knit layer <NUM> and/or inner knit layer <NUM> at least at some locations and not at others. Referring to <FIG>, which shows a cross-section of upper <NUM> taken along line <NUM>-<NUM> in heel region <NUM>, component <NUM> is coextensive with outer knit layer <NUM> and inner knit layer <NUM> at a bottom portion of article of footwear <NUM>. Upper or top edges of component <NUM> terminate within ankle region <NUM> of upper <NUM> while outer knit layer <NUM> and inner knit layer <NUM> extend beyond the component <NUM> to form ankle region <NUM>. Specifically, component <NUM> extends from a lateral bootie top edge <NUM> on lateral side <NUM> to a medial bootie top edge <NUM> on medial side <NUM>. Outer knit layer <NUM> and inner knit layer <NUM> extend beyond lateral bootie top edge <NUM> and medial bootie top edge <NUM> to form ankle region <NUM> and join at medial fold <NUM> and lateral fold <NUM>. As shown in <FIG>, in ankle region <NUM>, medial interstitial space <NUM> and lateral interstitial space <NUM> are empty, allowing ankle region <NUM> to behave and/or have characteristics more like a traditional sock. For example, ankle region <NUM> may have the flexibility to conform to the ankle of a wearer during use and/or to have suitable stretchability to accommodate the insertion and removal of the foot of a wearer.

In some embodiments, outer knit layer <NUM> and inner knit layer <NUM> are made from a common knit element <NUM> that is folded to form the layers <NUM> and <NUM>. In the embodiment shown in <FIG>, knit element <NUM> has been doubled over to form two layers. One embodiment of such an unfolded knit element <NUM> is shown in <FIG>. Making both layers of knit element <NUM> of upper <NUM> from a common unfolded knit element <NUM> may reduce costs, both in terms of knitting time and waste reduction, but also because folding unfolded element <NUM> into the folded orientation of knit element <NUM> may take less time and labor than aligning two separate pieces of material and joining the separate pieces of material together.

<FIG> show an embodiment of turning unfolded element <NUM> into a double-layer knit element like knit element <NUM>. <FIG> shows an embodiment of unfolded element <NUM>, where unfolded element <NUM> has a generally tubular, sock-like configuration. Unfolded element <NUM> includes two portions: a first portion <NUM> and a second portion <NUM>. First portion <NUM> and second portion <NUM> may be nearly identical in shape, though mirror-images and/or oppositely-oriented generally symmetrical portions. In some embodiments, first portion <NUM> and second portion <NUM> may have a foot-like shape with a toe such as first toe <NUM> and second toe <NUM>, and a shaped heel such as first heel <NUM> and second heel <NUM>.

In the illustrated embodiment of <FIG>, first portion <NUM> includes a first or open toe <NUM> so that a portion of an interior surface <NUM> of unfolded element <NUM> is visible. In contrast, the second portion <NUM> may have a second or closed toe <NUM>, that is closed either by joining edges together during a post-knitting process, during knitting (e.g., edges joined by a knit structure of the knit element <NUM> formed on a knitting machine), or otherwise closed by desirable or accepted methods. Closed toe <NUM> may alternatively be left open, at least initially, for example, in a manner like open toe <NUM>. In such embodiments, closed toe <NUM> may ultimately be closed to form a seam as discussed below in forming a seam to join open toe <NUM> to inner knit layer <NUM>.

Unfolded element <NUM> may be made using a suitable knitting process. In some embodiments, unfolded element <NUM> may be manufactured on a circular knitting machine. In some embodiments, first portion <NUM> and second portion <NUM> are made from the same type of yarn and with the same type of knit stitches. In other embodiments, first portion <NUM> and second portion <NUM> may be made from different types of yarn, different knit stitches and/or other knit structures, and/or with different knit stitch densities. Similarly, within each portion, first portion <NUM> and second portion <NUM> may be made with the same type of yarn and with the same type of knit stitches or other knit structures. In other embodiments, within first portion <NUM>, first portion <NUM> may include different types of yarn, different knit stitches or other knit structures, and/or different knit stitch densities. Similarly, second portion <NUM> may include different types of yarn, different knit stitches or other knit structures, and/or different knit stitch densities within second portion <NUM>.

First portion <NUM> and second portion <NUM> may be considered to be divided by a main fold line <NUM>. Main fold line <NUM> may be an imaginary line that apportions unfolded element <NUM> into first portion <NUM> and second portion <NUM>. In some embodiments, main fold line <NUM> may divide unfolded element <NUM> approximately in half. In other embodiments, first portion <NUM> may be slightly larger than second portion <NUM>, which may be advantageous when first portion <NUM> will be folded over second portion <NUM>, although it is also contemplated that second portion <NUM> may be larger. First portion <NUM> may, in some embodiments, surround or substantially surround second portion <NUM> to form outer knit layer <NUM>. Thus, when first portion <NUM> is not substantially larger than second portion <NUM>, first portion <NUM> may have sufficient stretch to encompass second portion <NUM> and to allow for interstitial space <NUM>. In these embodiments, the tension in the yarns of first portion <NUM> may assist in holding any components positioned in interstitial space <NUM> in a desired position.

As shown in <FIG>, a step in forming knit element <NUM> from unfolded element <NUM> includes grasping open toe <NUM> and turning the open end of first portion <NUM> essentially inside-out so that interior surface <NUM> becomes an exterior surface and first intermediate fold <NUM> is formed in first portion <NUM>. In some embodiments, in the final product, interior surface <NUM> of unfolded element <NUM> becomes exterior surface <NUM> (shown in <FIG>). After first portion <NUM> is turned or flipped inside-out, open toe end <NUM> is pulled in first fold direction <NUM>. First fold direction <NUM> is in the direction towards main fold line <NUM>.

<FIG> shows a subsequent point in the folding process. As shown, open toe <NUM> has been pulled past first portion heel <NUM> as shown in <FIG> so that first portion heel <NUM> is also turned inside out. Open toe <NUM> is also depicted as pulled past second portion heel <NUM> in a second fold direction <NUM>. Open toe <NUM> is shown as approaching closed toe <NUM>. At this stage, interior surface <NUM> may form a majority of an exterior surface of the illustrated element. The wearable orientation of outer knit layer <NUM> and inner knit layer <NUM> is, at this point, more clearly visible.

<FIG> shows yet another optional point in the folding process, wherein open toe <NUM> is pulled past closed toe <NUM> prior to the final step. By pulling open toe <NUM> past closed toe <NUM>, technical properties and/or aesthetic qualities of outer knit layer <NUM> may extend up to and be coterminous with closed toe <NUM>. Furthermore, at this stage, pulling open toe <NUM> past closed toe <NUM> may enable forming a toe seam <NUM> by alternative post-process methods, described below.

<FIG> shows an embodiment of a final step in the folding process. In this step, open toe <NUM> may be pulled proximate closed toe <NUM>. In some embodiments, such as the illustrated embodiment, open toe <NUM> aligns with closed toe <NUM>. In other embodiments, open toe <NUM> may fall short of closed toe <NUM> or be pulled past closed toe <NUM> (as shown in <FIG>). In embodiments where open toe <NUM> may be pulled past closed toe <NUM>, outer knit layer <NUM> may be temporarily joined with closed toe <NUM> prior to forming the toe seam <NUM>. Also, an excess portion <NUM> of outer knit layer <NUM> that extends beyond closed toe <NUM> may be removed prior to or subsequent to forming the toe seam <NUM>. Open toe <NUM> may be affixed to inner knit layer <NUM> to form the toe seam <NUM>, which may be positioned in an over-toe area, and underfoot area, or other area. Toe seam <NUM> may be formed by one or more steps, including but not limited to stitching, adhesive bonding, heat bonding if the yarns of outer knit layer <NUM> and inner knit layer <NUM> include thermoset or thermoplastic properties, welding through an RF welding or sonic welding process, or the like. Heat bonding, RF welding, and sonic welding may provide benefits over other types of joining process by reducing labor costs and material waste, by enabling toe seam <NUM> to have smaller dimensions and/or reside below a bite line where it is not visible (for example in an underfoot area), and/or by providing a seamless on-foot feel to the user (for example, by eliminating "ears" created on the medial and lateral portions of the toe area by traditional toe-closing steps such as stitching). Any of the foregoing methods to form toe seam <NUM> may be carried out as a post-process step, i.e., after the upper is removed from a knitting machine.

When outer layer <NUM> and inner layer <NUM> are in their wearable configuration, as shown in <FIG>, knit element <NUM> may extend from toe seam <NUM> to main fold line <NUM>. Proximate main fold line <NUM> is a foot insertion opening <NUM>. Also proximate main fold line <NUM> is a main fold. As shown in <FIG>, main fold is shown at a top of ankle region <NUM> and includes a medial fold <NUM> and a lateral fold <NUM>. The main fold may be continuous around foot insertion opening <NUM>. Medial fold <NUM> and lateral fold <NUM> may be formed when first portion <NUM> fully overlaps second portion <NUM>. Main fold at main fold line <NUM> (shown in <FIG>) may be a bend in knit element <NUM> that preserves the nature (e.g. the continuity) of unfolded knit element <NUM> while forming two distinct layers: outer knit layer <NUM> and inner knit layer <NUM>.

In some embodiments, component <NUM> may be positioned on first portion <NUM> and/or second portion <NUM> or between these portions <NUM> and <NUM> prior to or during the folding of unfolded element <NUM> into knit element <NUM>. In one particular example (e.g., when the component <NUM> is a bootie as depicted), second portion <NUM> may be inserted into component <NUM> then first portion <NUM> may be folded around component <NUM>. In other embodiments, component <NUM> (and/or other components) may be inserted between first portion <NUM> and second portion <NUM> after portions <NUM> and <NUM> are substantially folded or otherwise manipulated into their wearable orientation.

<FIG> show various embodiments of an article of footwear with a knitted element, where different components and/or knit structures are used in different zones of an article of footwear to achieve different properties in different zones. For example, different portions or zones of an article of footwear may benefit from different structural or performance properties. In some zones, such as in the forefoot region, breathability and flexibility are beneficial. In other zones, such as in a heel or toe, rigid support and protection may be beneficial.

In the embodiment(s) shown in <FIG>, an article of footwear <NUM> includes an upper <NUM> and an optional sole structure <NUM>. In most respects, upper <NUM> is similar to upper <NUM> and second sole structure <NUM> is similar to sole structure <NUM>, both of which are discussed above with reference to <FIG>. For example, second knit element <NUM> may optionally be made from the same materials and folded in the same way as knit element <NUM> discussed above. In some embodiments, such as the embodiment shown in <FIG>, second knit element <NUM> may include at least one zonal pocket which is configured to contain at least one zonal insert.

Upper <NUM> may include zonal pockets sandwiched between a first knit layer <NUM> and a second knit layer <NUM>. Zonal pockets and inserts may be provided to produce different responses and properties in different parts of article of footwear <NUM>. In the embodiment shown in <FIG>, three zonal pockets are provided: a first zonal pocket <NUM> disposed in second heel region <NUM>, a second zonal pocket <NUM> disposed on a medial side <NUM> of second midfoot region <NUM>, and a third zonal pocket <NUM> disposed in a toe region of second forefoot region <NUM>. As shown best in <FIG>, first zonal pocket <NUM> is configured to receive a first zonal insert <NUM> within a first pocket interior <NUM>, second zonal pocket <NUM> is configured to receive a second zonal insert <NUM> within a second pocket interior <NUM>, and third zonal pocket <NUM> is configured to receive a third zonal insert <NUM> within a third pocket interior <NUM>.

Greater or fewer zonal pockets may be provided in other embodiments. In some embodiments, the number of zonal pockets may exceed the number of zonal inserts. For example, when a single design of knit element <NUM> is provided for a number of different configurations, some of the pockets may remain empty in some configurations. In other embodiments, the number of zonal pockets may be less than the number of zonal inserts, such as when zonal inserts may be provided in a kit for interchangeability or when more than one zonal insert is intended to be positioned in a zonal pocket for a finer degree of control over the properties contributed by the zonal inserts.

As shown in the cross-sectional view of <FIG>, which is taken along line <NUM>-<NUM> of <FIG> and through second zonal pocket <NUM>, second zonal pocket <NUM> is disposed in an interstitial space <NUM> formed between outer knit layer <NUM> and inner knit layer <NUM> on medial side <NUM> of upper <NUM>. Though second zonal pocket <NUM> is discussed, the same principles of placement, construction, and performance may apply equally to any zonal pocket discussed with respect to this or any other embodiment.

As illustrated in <FIG>, a second pocket panel <NUM> extends between outward-facing surface <NUM> and inward-facing surface <NUM> within interstitial space <NUM>. In some embodiments, second pocket panel <NUM> may be attached to outward-facing surface <NUM>, while in other embodiments, pocket panel <NUM> may be attached to inward-facing surface <NUM>. In some embodiments, second pocket panel <NUM> may be formed integrally (e.g., formed with a common knit structure on a knitting machine) with at least one of second outer knit layer <NUM> and/or second inner knit layer <NUM>. In other embodiments, second pocket panel <NUM> may be formed separately and then sewed, adhered, heat bonded, and/or welded to at least one of outer knit layer <NUM> and inner knit layer <NUM>.

Second pocket panel <NUM> may define a second pocket interior <NUM>. In the illustrated embodiment, second pocket interior <NUM> is defined by second pocket panel <NUM> and outward-facing surface <NUM>. In other embodiments, second pocket interior <NUM> may be defined by second pocket panel <NUM> and inward-facing surface <NUM>. Thus, one of outer knit layer <NUM> and inner knit layer <NUM> may form one wall of a pocket while the other wall of the pocket may be formed from second pocket panel <NUM>. In some embodiments, another pocket panel may be included to define another wall of second pocket interior <NUM>.

Second pocket interior <NUM> may configured to receive second zonal insert <NUM>. In the illustrated embodiment, second zonal insert <NUM> is positioned between second pocket panel <NUM> and outward-facing surface <NUM>. In other embodiments, second zonal insert <NUM> may be positioned between second pocket panel <NUM> and inward-facing surface <NUM>. In other embodiments, second pocket panel <NUM> may be eliminated entirely so that second zonal insert <NUM> may be positioned in interstitial space <NUM>. Pocket panel <NUM> generally serves the purpose of holding second zonal insert <NUM> in a specific location within upper <NUM>. In embodiments that do not utilize a pocket panel like second pocket panel <NUM>, the pocket may be formed by attaching a portion of second outer layer <NUM> directly to inner knit layer <NUM>, such as with integrated knitting, stitching, adhesive bonding, heat bonding, and/or welding.

The structure of a pocket, in particular, first zonal pocket <NUM>, is shown in detail in <FIG> and <FIG>. As depicted, first zonal pocket <NUM> is formed by associating first pocket panel <NUM> with outward-facing surface <NUM>. Therefore, outward-facing surface <NUM> forms a first wall of first pocket interior <NUM> while first pocket panel <NUM> forms an opposite wall of first pocket interior <NUM>. First pocket panel <NUM> may be coupled to outward-facing surface <NUM> on three edges, as denoted by the panel attachment line <NUM>. The attachment of first pocket panel <NUM> is shown further in <FIG>, which is a cross-sectional view of <FIG>. First panel attachment <NUM> and second panel attachment <NUM> may affix opposite edges of first pocket panel <NUM> to outward-facing surface <NUM>. The attachment <NUM> may include sewing, adhesive bonding, heat bonding, welding, or any other suitable device or method.

The attachment of first pocket panel <NUM> to outward-facing surface <NUM> may advantageously allow for easy access into first pocket interior <NUM>. As shown best in <FIG>, a pocket lip <NUM> may not be attached to outward-facing surface <NUM>, and pocket lip <NUM> may be a free end of first pocket panel <NUM> that can be pulled away from outward-facing surface <NUM> to permit access into first pocket interior <NUM>. This may allow a manufacturer to slide first zonal insert <NUM> into first pocket interior <NUM>. The same or a similar structure as first zonal pocket <NUM> may apply equally to second zonal pocket <NUM> and third zonal pocket <NUM>.

Zonal inserts <NUM>, <NUM>, and <NUM> may be configured (e.g., sized, shaped, and formed of a material with particular properties) to provide upper <NUM> with specific properties proximate zonal pockets <NUM>, <NUM>, and <NUM>. In some embodiments, all zonal inserts <NUM>, <NUM>, and <NUM> may provide the same property to upper <NUM>. Alternatively, each zonal insert may provide different properties, depending upon the location of the zonal insert on upper <NUM>. For example, first zonal insert <NUM> may be sized, shaped, or otherwise configured to act as a heel counter, which may be rigid and stiff compared to the rest of upper <NUM>. Second zonal insert <NUM> may be sized, shaped, or otherwise configured to act as an arch support, so second zonal insert <NUM> may be sized, shaped, or otherwise configured to follow the contours of an arch while being supportive and cushioning. Third zonal insert <NUM> may be sized, shaped, or otherwise configured to act as a toe cap, which may be rigid and stiff compared to the rest of upper <NUM>, but may be made of a more breathable material than that of first zonal insert <NUM>. In some embodiments, one or more zonal properties may be common to more than one or even all zonal inserts, such as cushioning, while other properties vary from zonal insert to zonal insert, such as stiffness and breathability.

Each zonal insert <NUM>, <NUM>, and <NUM> may optionally be made from the same material, or one or more of the zonal inserts <NUM>, <NUM>, and <NUM> may be made from different materials. Example materials may include natural or synthetic rubber, foams, polymer sheets or plates, cushioning bladders that may be filled with foams, gas, and/or fluids, combinations of these materials, knit or other textiles, and/or other suitable materials and combinations.

The embodiment(s) of <FIG> show that zonal inserts are disposed in the layers of upper <NUM> so that the zonal inserts are spaced apart/do not touch while portions of upper <NUM> do not contain any inserts. In other embodiments, such as the embodiment shown in <FIG> and <FIG>, substantially the entirety of an upper <NUM> may include zonal inserts that are shaped to provide properties to various zones of the upper <NUM>.

The upper <NUM> of <FIG> is similar to the upper <NUM> of <FIG> in many respects. For example, the upper <NUM> is depicted as including a knit element <NUM> that is folded to form an outer layer <NUM> and an inner layer <NUM>, shown in <FIG>. Knit element <NUM> may be similar in materials and structure to knit element <NUM> (of <FIG>). However, the zonal pockets formed in an interstitial space formed between outer layer <NUM> and inner layer <NUM> and the zonal inserts positioned within those pockets are different from the zonal pockets described above. In the illustrated embodiment of upper <NUM>, the zonal pockets and zonal inserts abut each other and have irregular edges that fit together like the pieces of a puzzle. The coverage of upper <NUM> assists in providing an upright structural shape to upper <NUM>, while the shapes of the pockets and inserts are configured to follow the contours of the foot of a wearer to provide more specific zonal support and properties to the various areas of upper <NUM> proximate the zonal pockets.

The depicted upper <NUM> includes a first irregular zonal pocket <NUM>, a second irregular zonal pocket <NUM>, a third irregular zonal pocket <NUM>, and a fourth irregular zonal pocket <NUM>. First irregular zonal pocket <NUM> and first irregular zonal insert <NUM> are disposed in heel region <NUM>. First irregular zonal insert <NUM> may generally have the configuration and properties of at least a portion of a heel counter. First irregular zonal pocket <NUM> is configured to receive first irregular zonal insert <NUM> and conforms generally to the shape of first irregular zonal insert <NUM>.

Second irregular zonal pocket <NUM> and second irregular zonal insert <NUM> may be partially disposed in heel region <NUM> and ankle region <NUM>, span third midfoot region proximate sole structure <NUM>, and terminate in forefoot region <NUM>. Second irregular zonal insert <NUM> may have properties that provide flexible and cushioning support to the portions of upper proximate second irregular zonal insert <NUM>. Additionally or alternatively, second irregular zonal pocket <NUM> may be configured to receive second irregular zonal insert <NUM> and may conform generally to the shape of second irregular zonal insert <NUM>. As shown in <FIG>, second irregular zonal insert <NUM> may have a second thickness <NUM>. Second thickness <NUM> may be uniform throughout second irregular zonal insert <NUM>, or second thickness <NUM> may vary through second irregular zonal insert <NUM>. The variation in thickness may provide thinned portions of irregular zonal insert <NUM> for enhanced flexibility or thickened portions for enhanced stiffness and support. Second irregular zonal insert <NUM> may also include a second perimeter edge <NUM> that is shaped to extend portions of second irregular zonal insert <NUM> away from sole structure <NUM> to provide cushioning along the sides of upper <NUM> while also providing gaps between the portions to enhance flexibility. Similarly, third irregular zonal pocket <NUM> and fourth irregular zonal pocket <NUM> may be configured to receive third zonal insert <NUM> and fourth zonal insert <NUM>, respectively, and each of these elements may include any of the features described above with respect to second irregular zonal pocket <NUM> and second irregular zonal insert <NUM>. Any of the zonal pockets of upper <NUM> may be constructed similarly to the zonal pockets of upper <NUM> (of <FIG>), but the zonal pockets of upper <NUM> may have different shapes. Similarly, any of the zonal inserts of upper <NUM> may optionally be made of similar materials as the zonal inserts of upper <NUM>, but this is not required.

In some embodiments, such as the embodiment shown in <FIG>, an upper may be knitted to include a visual and/or machine-detectable cue as to the properties of regions and/or may include visible or machine-detectible bite lines to similarly indicate to a technician or a manufacturing machine the intended placement of elements such as a sole structure or a throat opening support. The cue and/or bite lines may additionally or alternatively be included for purposes of providing the article of footwear with desirable aesthetic properties and effects. The features illustrated by <FIG> and described below may be used in combination with any of the other embodiments of this disclosure.

Knit element <NUM> depicted in <FIG> may be similar in materials and structure to knit element <NUM> (of <FIG>). In some respects, knit element <NUM> may be similar and has many of the same traits, structures, and performance characteristics of to upper <NUM> of article of footwear <NUM>.

While article <NUM> may include zonal pockets and/or zonal inserts such as those described above, these zonal pockets are not shown for the sake of clarity. Instead, article <NUM> may be provided with zonal features or additional zonal features based on the type of yarn used in a zone, the type of knit stitch or other knit structure used in a zone, and/or the knit density in a zone. For the purposes of this discussion, knit density may be considered to be the number of stitches per unit of length or area.

<FIG> shows several different zones on knit element <NUM>: a first zone <NUM>, a second zone <NUM>, a third zone <NUM>, a fourth zone <NUM>, a fifth zone <NUM>, a sixth zone <NUM>, and a seventh zone <NUM>. Each of these zones may have different structural, performance, and/or aesthetic properties. In addition to type of yarn used in a zone, the type of knit stitch or other knit structure used in a zone, and/or the knit density in a zone, some of the differing properties of the knit element <NUM> may include stretch resistance, breathability, and stiffness.

In the embodiment of <FIG>, first zone <NUM> spans from heel <NUM> to toe <NUM> along a lowermost portion of knit element <NUM>. First zone <NUM> may be configured (e.g., with certain materials and/or surface characteristics) to receive a sole structure. In some embodiments, first zone <NUM> may be stiffer than other zones to form a stable surface for receiving a sole structure. In some embodiments, first zone <NUM> may be thicker than other zones to form a more comfortable surface for a foot. In some embodiments, first zone <NUM> may include more thermoplastic polymer yarns than other zones so that a sole structure may be readily heat bonded and/or welded to first zone <NUM>. In some embodiments, first zone <NUM> may include a type of yarn that is more compatible with an adhesive than the other zones so that first zone <NUM> may be more easily adhesive bonded to a sole structure. In some embodiments, first zone <NUM> may be a combination of any of these properties.

Second zone <NUM> extends from midfoot region <NUM> and into forefoot region <NUM> from a forward part of ankle region <NUM> along a top of knit element <NUM>. In some embodiments, second zone <NUM> may be more elastic than other regions so that second zone <NUM> may stretch to accommodate a foot insertion and return to an original size to secure knit element <NUM> to the foot. In some embodiments, second zone <NUM> may be configured to receive a lacing system reinforcing structure. When included, the lacing system may include eyelets, which may be punched out of the second zone <NUM> (e.g., post-knitting), or may be knitted directly into second zone <NUM>. In embodiments with knitted eyelets, the eyelets may be formed by knitting float stitches (for example a one- or two-stitch float on a circular knitting machine). Each eyelet may include an entrance and an exit, each of which may include one or more yarns selected for durability and abrasion resistance. For example, knitted eyelets may comprise high tenacity yarns and/or thermoplastic yams activated by suitable post-processing step. In some embodiments, second zone <NUM> may be thicker than other zones to provide additional comfort to the top of a foot proximate the laces. In some embodiments, second zone <NUM> may include more thermoplastic yarns than other zones so that a reinforcing structure may be readily heat bonded and/or welded to second zone <NUM>. Optionally, second zone <NUM> may include a type of yarn that is more compatible with an adhesive than the other zones so that second zone <NUM> may be more easily adhesive bonded to a reinforcing structure. In some embodiments, second zone <NUM> may be a combination of any of these properties.

Third zone <NUM> may be positioned primarily in ankle region <NUM>. Third zone <NUM> may be significantly more elastic and have greater recovery capabilities than other zones, even than second zone <NUM>, so that third zone <NUM> may stretch to accommodate a foot insertion and return to an original size to secure knit element <NUM> to the ankle of a user.

Fourth zone <NUM> may be positioned adjacent third zone <NUM> and between first zone <NUM> and second zone <NUM>. Fourth zone <NUM> may be positioned proximate a portion of knit element <NUM> designed to cover a portion of a malleolus area of a user's foot. In some embodiments, fourth zone <NUM> may have stretch properties similar to third zone <NUM>, but may also have cushioning properties or other protective properties to assist in protecting the ankle of a wearer. In some embodiments, fourth zone <NUM> may be stiffer and/or less stretchy than third zone <NUM> to inhibit any potential rolling motion of a user's ankle. For example, fourth zone <NUM> may be selectively knit with yams having thermoplastic characteristics (e.g., that stiffen when heat activated) in order to provide ankle support.

Fifth zone <NUM> may be positioned adjacent to fourth zone <NUM> and between first zone <NUM> and second zone <NUM>. In some embodiments, fifth zone <NUM> may be stiffer than the surrounding zones to provide stability to knit element <NUM>. For example, fifth zone <NUM> may be selectively knit with yams having thermoplastic characteristics (e.g., that stiffen when heat activated) in order to provide medial and lateral support.

Sixth zone <NUM> may be positioned adjacent to fifth zone <NUM> and extends between first zone <NUM> and second zone <NUM>. In some embodiments, sixth zone <NUM> may be less stiff than the surrounding zones to increase the flexibility of knit element <NUM> proximate the toe joints of a user.

Seventh zone <NUM> may be positioned in fourth forefoot region <NUM> and is configured to cover the toes of a user when the user's foot is inside knit element <NUM>. In some embodiments, seventh zone <NUM> may be more breathable than the surrounding zones. In other embodiments, seventh zone <NUM> may incorporate materials, such as yarns with thermoplastic polymer materials, that aid in the formation of toe seam <NUM>, as described above.

<FIG> shows an embodiment of an unfolded element <NUM> that may be folded or otherwise manipulated into a double-layer knit element like knit element <NUM>. Unfolded element <NUM> may include the same pattern of yarns as shown in <FIG>, or unfolded element <NUM> may include a simplified pattern as shown so that a first bite line <NUM> is positioned on a first part of unfolded element <NUM> and a second bite line <NUM> may be positioned between first part <NUM> and a second part <NUM> of unfolded element <NUM>. The simplified pattern may include a first area <NUM> having first zonal properties, a second area <NUM> having second zonal properties, a third area <NUM> having third zonal properties, a fourth area <NUM> having fourth zonal properties, and a fifth area <NUM> having fifth zonal properties, and the like. The zonal properties may be any of the types of zonal properties noted above with respect to knit element <NUM>, or any other suitable type. In this simplified embodiment, second area <NUM> may have similar or substantially identical properties to fifth area <NUM>, and third area <NUM> may have similar or substantially identical properties to fourth area <NUM>.

<FIG> shows an embodiment of unfolded element <NUM> where unfolded element <NUM> has a generally tubular, sock-like configuration. First part <NUM> and second part <NUM> are nearly identical in shape, though mirror-images or oppositely-oriented. In some embodiments, first part <NUM> and second part <NUM> may have a foot-like shape similar to unfolded element <NUM>, discussed above.

In the illustrated embodiment, first part <NUM> includes an open toe <NUM>, and second part <NUM> has a closed toe <NUM>, where the edges of the tubular element have been knitted or otherwise joined together. In some embodiments, closed toe <NUM> may also be left open. In such embodiments, closed toe <NUM> may include a seam as discussed below.

Unfolded element <NUM> may be folded or otherwise manipulated in much the same way as unfolded element <NUM> discussed above with reference to <FIG>. However, unfolded element of <FIG> may additionally include second bite line <NUM> for use as a guide for the folding process, while unfolded element <NUM> (of <FIG>) shows no such guide line. A folding machine may use sensors such as laser detection systems or visual inspection systems that utilize captured images of unfolded element <NUM> and bite line <NUM> to detect where the main fold should be, while a technician may be able to use bite line <NUM> as a simple visual guide for accurate folding. Quality control inspection devices and inspectors may find that second bite line <NUM> or other visual/detectable cues on second unfolded element <NUM> may provide for faster and more accurate inspection.

<FIG> and <FIG> show an embodiment of how bite line <NUM> may be used to guide the placement of a sole structure <NUM> onto an upper <NUM> that includes knit element <NUM>. As shown in <FIG>, sole structure may include a perimeter edge <NUM> configured (e.g., sized and shaped) to follow the same contours as bite line <NUM>. While shown in the illustrated embodiment as an irregular edge, perimeter edge <NUM> may instead have a smooth edge or a different contour. Bite line <NUM> and perimeter edge <NUM> may be aligned so that perimeter edge <NUM> follows the contours of bite line <NUM>. <FIG> shows article <NUM> with sole structure <NUM> affixed to upper <NUM> so that sole structure <NUM> covers first zone <NUM> so that perimeter edge <NUM> follows first bite line <NUM>. In other embodiments, perimeter edge <NUM> may obscure part or all of first bite line <NUM> when positioned onto upper <NUM>. Sole structure <NUM> may be affixed to upper <NUM> using techniques including but not limited to sewing, adhesive bonding, heat bonding, and/or welding.

<FIG> illustrate a knitted component <NUM> including an outer knit layer <NUM> pulled over an inner knit layer (not shown), and further incorporating a sole structure <NUM>, where the outer knit layer <NUM> incorporates a retention system <NUM> for exerting a tension force on a wearer's foot. The retention system <NUM> may be incorporated into retention zones <NUM> which may be preferably located on the medial and/or lateral portions of the outer knit layer <NUM> and extend longitudinally along the knitted component <NUM>. The retention system <NUM> may include one or more first yarns <NUM> (such as 650a, 650c, 650e, and <NUM>) configured to provide medial-to-lateral support (e.g., medial-to-lateral lock-out) when a wearer places a foot into the knitted component <NUM>. The retention system <NUM> may additionally and optionally include one or more second yarns <NUM> (such as depicted second yarns 660a, 650c, 650e, and <NUM>) for biasing the retention system <NUM> to a first state when a wearer's foot is not positioned within the knitted component <NUM>. Additionally, the retention system <NUM> may optionally include one or more third yarns <NUM> (such as the depicted third yarns 670a, 670c) that shield at least one first yarn <NUM> from abrasion, snagging, and other causes of damage while advantageously preserving ventilation and visibility of the first yarns.

Still with reference to <FIG>, the first yarns 650a-g may be knitted to form intermeshed loops of outer knit layer <NUM> or may be inlaid within intermeshed loops of outer knit layer <NUM>, and may generally have an orientation substantially in the medial and lateral directions, in the heel and forefoot directions, or in other orientations. It is also possible for the first yarns 650a-g to include at least one first yarn <NUM> that is inlaid and different first yarn(s) <NUM> that are looped. Optionally, when the retention system <NUM> includes first yarns <NUM> with knitted loops, the first yarns <NUM> may include floating portions that float (i.e., extend without a loop) past a series of wales. The floating portions may be formed when the floating portions of the first yarns <NUM> skip (i.e., extend past without engaging) a series of consecutive needles on a needle bed during when knitting a course during a knitting process. The needle bed may be a needle bed of a circular knitting machine. The course-wise length along each first yarn <NUM> between the loops immediately adjacent to the ends of the floating portion may be referred to as the float length. When first yarns <NUM> are taut, the float length may form a relatively straight dimension that may be parallel to and define a course-wise dimension of the retention zones 642a-b (i.e., the vertical dimension from the perspective of <FIG>). When the first yarns <NUM> are not taut, the float length may not form a relatively straight dimension, and may not define the course-wise dimension of the retention zones 642a-b. The number of consecutive floated courses of the first yarn <NUM> may generally define a wale-wise dimension of the retention zones 642a-b (i.e., the horizontal dimension from the perspective of <FIG>). This knit structure results in each knitted first yarn <NUM> being loose from the rest of the knitted component within the retention zones 642a-b. Because the first yarns <NUM> have a nominal stitch length within the float length, and because the first yarns <NUM> may be constructed from a material with low stretch, the first yarns <NUM> may have very low stretch along the course-wise direction (depicted as vertical) within the retention zone <NUM> (at least when the first yarns <NUM> are taut).

More than one retention zone <NUM> may be included. As shown in <FIG>, for example, two retention zones 642a-b may be included. Retention zone 642a may be spaced or otherwise separated from the retention zone 642b by a portion <NUM> of the outer knit layer <NUM>. Portion <NUM> of the knitted layer may include loops formed by the first yarns 650a-g. Advantageously, providing two (or more) retention zones 642a-b may increase the amount the retention system can displace between its first and second states with respect to the inclusion of only one retention zone <NUM>. Further, it is contemplated that machine limitations may limit maximum float length of first yarns 650a-g due to a maximum number of needles that may be skipped without interrupting the knitting process (e.g., <NUM> needles according to one test performed by an inventor). Thus, to mitigate this limitation, the portion <NUM> of the outer knit layer <NUM> may include loops formed by the first yarns 650a-g.

Suitable materials for the first yarns <NUM> include yarns formed with low-stretch/low-elasticity materials with relatively high tensile strength, e.g., cables, strands, and cords. Exemplary materials that may be used for first yarns <NUM> may include strands or fibers having a low modulus of elasticity as well as a high tensile strength, such as tensile strands of monofilament material with a diameter of approximately <NUM> - <NUM>, or fibers such as SPECTRA™, manufactured by Honeywell of Morris Township N. Other suitable materials for first yarns <NUM> include various filaments, fibers, and yarns, that are formed from rayon, nylon, polyester, polyacrylic, silk, cotton, carbon, glass, aramids (e.g., para-aramid fibers and meta-aramid fibers), ultra-high molecular weight polyethylene, and liquid crystal polymer. In comparison with the second yarns <NUM>, the thickness of the first yarns <NUM> may be greater.

Still with reference to <FIG>, the second yams 660a-g may be knitted to form intermeshed loops of outer knit layer <NUM> or may be inlaid within intermeshed loops of outer knit layer <NUM>, and may have mechanical properties (e.g., a particular elasticity and resilience) for biasing the retention system <NUM> to a first state when the knitted component <NUM> is not on a wearer's foot. Exemplary materials for the second yarns 660a-g may include yarns that incorporates elastane fiber(s), such as those available from E. duPont de Nemours Company under the LYCRA trademark. Such yarns may have the configuration of covered LYCRA, for example yarns having a LYCRA core that is surrounded by a nylon sheath. Other fibers or filaments exhibiting elastic properties may also be utilized.

Still with reference to <FIG>, the third yarns <NUM> (shown as 670a-c in <FIG> and not shown in <FIG>) may be knitted to form a knit structure of intermeshed loops of the outer knit layer <NUM> or inlaid within intermeshed loops of outer knit layer <NUM>. The third yarns <NUM> may include yarns with suitable durability, such as monofilament yarns or other yarn with high resistance to abrasion and breakage. In <FIG>, third yarns 670a-c are represented schematically, and <FIG> does not necessarily correspond to the orientation or stitch type of third yarns 670a-c. Generally, third yarns <NUM> may be formed from a knit stitch, tuck stitch, or other suitable stitch or other knit structure, and may be oriented as necessary to form a lattice, covering, or other protective knit structure for the first yarns <NUM>. In some embodiments, at least one of the first yarns <NUM> may reside behind at least one of the third yarns <NUM> when the outer knit layer <NUM> is pulled over the inner knit layer <NUM>, so that an exterior surface of at least one of the first yarns <NUM> is covered by at least one of the third yarns <NUM>. In other words, in use, when a wearer's foot is placed within the knitted component <NUM>, at least one of the first yarns <NUM> may reside between the wearer's foot and at least one of the third yarns <NUM>, i.e., at least one of the third yarns <NUM> may reside over at least one of the first yarns <NUM>.

Still with reference to <FIG>, before a wearer places a foot in the knitted component <NUM>, the knitted component <NUM> may assume a relatively limp, sock-like state. The second yarns 670a-f may bias the knitted component <NUM> to a first state, in which the second yarns 670a-f may assume a contracted state and the first yarns 650a-f may assume a slack state, as shown, where the float length of the first yarns 650a-f is greater than the corresponding course-wise dimension of the retention system. By inserting a foot into the knitted component <NUM>, as shown in <FIG>, a wearer stretches the second yarns 670a-f into a second state, at which point the second yarns 670a-f stretch and provide a snug on-foot feel by creating tension in the portion of the knitted component <NUM> around the bridge of the wearer's foot. Also, by inserting a foot into the knitted component <NUM>, a wearer causes the first yarns 650a-f to become taut, as shown in <FIG>. Because the first yarns 650a-f may be constructed of materials with relatively low stretch and high tensile strength, the first yarns 650a-f may experience tensile stress in the second state and tend to resist further elongation. This tends to retain the knitted component <NUM> on the wearer's foot without additional steps (e.g., tying a lace), and also retain the wearer's foot on the sole structure <NUM>. In other words, the retention system exerts a tension force (e.g., a tension force in the first yarns <NUM>) to retain the knitted component <NUM> on the wearer's foot. The tension force may also include tensile forces present in the second yarns. In some embodiments, conventional elements like a tongue may be provided. In the illustrated embodiments, however, the sock-like nature of the knit elements may not require a traditional tongue as the ankle region may stretch to accommodate foot insertion and retract to secure the foot snugly within the knitted component. In some embodiments, closure elements can also be included that is used to selectively secure a knitted component to the wearer's foot. A closure element can be of any suitable type, such as a lace. In other embodiments, the closure element(s) may also include one or more buckles, straps, or other suitable implements for securing the knitted component to a wearer's foot. In the illustrated embodiments, however, the knitted component may be configured to be pulled over a user's foot like a sock, and, thus, may not include any additional closure elements. When a closure element is included, the closure element may operate in conjunction with the retention system <NUM> of <FIG>, but it is also contemplated that the retention force provided by the retention system <NUM> may render an additional closure element unnecessary.

In further configurations, any of the knitted components disclosed above may include additional elements. For example, upper <NUM> (of <FIG>, or any other upper described herein) can include a toe guard in forefoot region that is formed of a wear-resistant material. The upper can additionally include logos, trademarks, symbols, and placards with care instructions and material information. It will be appreciated that any upper disclosed above can include still further elements without departing from the scope of the present disclosure.

The filaments of the nonwoven layers, knitted materials, components, or inserts in any of the embodiments discussed above may include a thermoplastic polymer material. In general, a thermoplastic polymer material melts when heated and returns to a solid state when cooled. More particularly, the thermoplastic polymer material transitions from a solid state to a softened or liquid state when subjected to sufficient heat, and then the thermoplastic polymer material transitions from the softened or liquid state to the solid state when sufficiently cooled. As such, the thermoplastic polymer material may be melted, molded, cooled, re-melted, re-molded, and cooled again through multiple cycles. Thermoplastic polymer materials may also be bonded or fused, as described in greater detail below, to other textile elements, plates, sheets, polymer foam elements, thermoplastic polymer elements, thermoset polymer elements, or a variety of other elements formed from various materials. In contrast with thermoplastic polymer materials, many thermoset polymer materials do not melt when heated, simply burning instead. Although a wide range of thermoplastic polymer materials may be utilized for the filaments of a nonwoven or knitted material or an insert or component, examples of some suitable thermoplastic polymer materials include thermoplastic polyurethane, polyamide, polyester, polypropylene, and polyolefin. Although any of the thermoplastic polymer materials mentioned above may be utilized for the above-discussed embodiments, an advantage to utilizing thermoplastic polyurethane relates to heat bonding and colorability. In comparison with various other thermoplastic polymer materials (e.g., polyolefin), thermoplastic polyurethane is relatively easy to bond with other elements, as discussed in greater detail below, and colorants may be added to thermoplastic polyurethane through various conventional processes.

Claim 1:
An article of footwear (<NUM>) comprising a knitted component (<NUM>) forming an overfoot portion and an underfoot portion of the article of footwear (<NUM>), the knitted component (<NUM>) comprising:
a first layer (<NUM>) forming an interior surface (<NUM>) defining a void (<NUM>);
a second layer (<NUM>), wherein the second layer (<NUM>) at least partially surrounds the first layer (<NUM>), wherein the second layer (<NUM>) forms an outer surface on the overfoot portion and the underfoot portion, and
wherein a portion of the first layer (<NUM>) is continuous with a portion of the second layer (<NUM>) in an ankle region (<NUM>) of the knitted component (<NUM>);
an interstitial space (<NUM>) formed between the first layer (<NUM>) and the second layer (<NUM>);
wherein the knitted component (<NUM>) is characterized by at least one pocket (<NUM>) located within the interstitial space; and
a component (<NUM>) disposed between the first layer (<NUM>) and the second layer (<NUM>) within the pocket (<NUM>).