ARTICLE OF FOOTWEAR WITH EASY DONNING FEATURES AND METHOD OF MANUFACTURING THE SAME

Description

CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY CLAIM

This non-provisional application claims priority to co-pending U.S. Provisional Patent Application No. 63/721,037, filed on November 15, 2024, and titled “ARTICLE OF FOOTWEAR WITH EASY DONNING FEATURES AND METHOD OF MANUFACTURING THE SAME.” The entire contents of this priority application are herein incorporated by reference.

BACKGROUND

Traditional articles of footwear can include elements, such as an elastically resilient structure that is positioned in the heel region of the upper, that facilitate a wearer donning the article of footwear by using their heel to press down on a collar region of the article of footwear while inserting their foot into the article of footwear. The element then facilitates the collar region returning to an elevated state. However, articles of footwear that include these elements lack textile features that may enhance the use of such elastically resilient structures so as to further facilitate easy, substantially hands-free donning of the article of footwear, increase durability, and maintain aesthetic features of the article of footwear.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of the present articles of footwear with easy donning features and methods of manufacturing the same are described in detail below with reference to the attached drawing figures, wherein:

FIG. 1 illustrates a side view of an example article of footwear having features that facilitate easy donning, in accordance with aspects herein;

FIG. 2 illustrates a top view of the article of footwear of FIG. 1, in accordance with aspects herein;

FIG. 3 illustrates a rear view of the article of footwear of FIG. 1, in accordance with aspects herein;

FIG. 4 illustrates an example upper that can be incorporated into the article of footwear of FIG. 1, in accordance with aspects herein;

FIG. 5A illustrates a schematic of a knit structure that includes a low-melting yarn plated with a high-melting yarn prior to heat and/or pressure being applied to the knit structure, in accordance with aspects herein;

FIG. 5B illustrates a schematic of the knit structure of FIG. 5A after heat and/or pressure have been applied to the knit structure, in accordance with aspects herein;

FIG. 6A illustrates a side perspective view of the article of footwear of FIG. 1 depicting an example collar elevator in a first position, in accordance with aspects herein;

FIG. 6B illustrates a side view of the article of footwear of FIG. 5A depicting the collar elevator in a second position, in accordance with aspects herein;

FIG. 7A illustrates a wearer in the process of donning the article of footwear of FIG. 1, in accordance with aspects herein;

FIG. 7B illustrates the wearer of FIG. 7A with the article of footwear of FIG. 1 in a substantially donned state, in accordance with aspects herein; and

FIG. 8 illustrates a block diagram of an example method of manufacturing an article of footwear, in accordance with aspects herein.

DETAILED DESCRIPTION

In brief, and at a high level, aspects herein are directed to an article of footwear incorporating an upper and methods of manufacturing an article of footwear and an upper thereof, such that the upper includes knit textile features that can operate in combination with one or more other elements or structures to facilitate easy, substantially hands-free donning of the article of footwear.

In aspects, an upper for an article of footwear is provided. The upper can include an integrally knit, one-piece structure that extends at least partially through a forefoot region, a midfoot region, a heel region, a vamp, and/or an ankle collar defining a perimeter around a foot-insertion opening into a foot-receiving cavity, where the ankle collar includes a topline edge. In some aspects, the vamp can extend from the forefoot region or toe end to the topline edge.

In aspects, an article of footwear is provided. The article of footwear can include a collar elevator provided as, for example, an elastically-resilient structure that is integrated at least partially into a heel region. The collar elevator can be adapted to shift at least partially downward from a first position to a second position in response to a downward force applied to the collar elevator due to insertion of a foot through the foot-insertion opening. This downward shift can cause the foot-insertion opening to temporarily and reversibly expand at the topline edge. The collar elevator can be adapted to rebound upward and back to the first position upon removal of the downward force.

In aspects, at least a first yarn type is used to knit at least the forefoot region and the midfoot region of the upper. The first yarn type can include yarns having a relatively higher tenacity and abrasion resistance, e.g., polyethylene terephthalate yarns (PET yarns), commonly known as polyester. In aspects, a low-melting yarn(s) that includes a thermoplastic material, e.g., a thermoplastic polymeric composition, may be plated with the first yarn type in at least the forefoot and midfoot regions, and in a post-knitting step, heat and/or pressure may be applied to the upper, causing the low-melting yarn(s) to soften, partially melt, and/or melt. Upon cooling, the melted material re-solidifies, and the yarns of the first yarn type may be at least partially embedded within the re-solidified thermoplastic polymeric composition, which may help to provide structure and/or a degree of rigidity to at least the forefoot and midfoot regions of the upper. The enhanced structure and/or rigidity in these areas may provide improved foot containment, may prevent the forefoot and midfoot regions from collapsing during the shoe-donning process, and may inhibit the wearer’s foot from shifting within the article of footwear.

In aspects, a second yarn type that includes a greater number of elastically-resilient ends compared to the first yarn type may be used to knit, for example, the heel region and at least a first portion of the ankle collar that is located generally in the heel region. In some aspects, the second yarn type may include yarn ends of PET yarns and elastane yarns twisted together or otherwise combined or integrated to form a yarn that is strong and elastically resilient. In the first portion of the ankle collar, the second yarn type may be plated with a low-melting yarn that includes a thermoplastic material, e.g., a thermoplastic polymeric composition, to provide structure and/or rigidity in this area once heat and/or pressure are applied to the upper. In use, the first portion of the ankle collar may be subject to a greater amount of compressive forces compared to other portions of the ankle collar, e.g., due to a wearer pressing down on the first portion of the ankle collar when inserting their foot into the foot-insertion opening. Having increased structure and/or rigidity in the first portion of the ankle collar may increase the durability of this area and may reduce creasing, which can enhance and improve the aesthetic aspects of the article of footwear. In some aspects, the heel region does not include low-melting yarns such that the heel region is less stiff and/or more pliable than the first portion of the ankle collar.

The use of elastically resilient yarns in the heel region and in the first portion of the ankle collar can help to facilitate a conforming and supportive fit around an Achilles tendon area of a wearer, which may increase wearer comfort, among other benefits. The use of elastically resilient yarns may also facilitate the heel region returning to a resting and/or elevated state after removal of the downward force from the collar elevator. More specifically, when the collar elevator moves downward from the first position to the second position in response to the downward force that occurs by way of the wearer’s foot pressing down on the ankle collar, the heel region shifts downward toward the sole structure. The use of elastically-resilient yarns in the heel region and the first portion of the ankle collar facilitates the heel region and the first portion of the ankle collar storing potential energy when the collar elevator is in the second position (e.g., the elastically-resilient yarns are stretched when the heel region is pressed downward). The stored potential energy in the heel region and in the first portion of the ankle collar results in these areas returning or rebounding upward to an elevated position after the downward force is removed from the collar elevator and the wearer’s foot is positioned within the article of footwear.

In aspects, the knitted upper may be tongue-less and at least a portion of the vamp adjacent to the topline edge (otherwise referred to as a “vamp portion” herein) may be knit with elastically-resilient yarns. The use of elastically-resilient yarns in the vamp portion facilitates the vamp portion reversibly expanding to accommodate the insertion of the wearer’s foot into the foot-receiving cavity, which can result in the donning process being easier. Once the foot is inserted, the elastically-resilient yarns help to provide support to and containment of the instep area of the wearer’s foot.

In aspects, in combination, the use of elastically-resilient yarns in the heel region, the first portion of the ankle collar, and the vamp portion may facilitate a hands-free or substantially hands-free shoe-donning experience. For example, a wearer may don the article of footwear by partially inserting their foot into the foot-receiving cavity and pressing downward on the collar elevator. The elastically-resilient vamp portion reversibly expands to accommodate the wearer’s foot. Additionally, the force applied by the wearer’s foot on the collar elevator causes the collar elevator to move downward from the first (resting and/or elevated) position to the second (depressed and/or compressed) position, which causes the foot-insertion opening to temporarily and reversibly expand at the topline edge. In addition, the force applied by the wearer’s foot causes a portion of the heel region to move downwardly toward the sole structure. The wearer can then fully insert their foot into the foot-receiving cavity. Once the force from the wearer’s foot is no longer applied to the collar elevator, the heel region and the first portion of the ankle collar can rebound to the first and/or elevated position, e.g., at least partially due to the use of the elastically-resilient yarn ends in this area.

In aspects, methods of manufacturing an upper with the aspects described herein, and methods of manufacturing an article of footwear with the aspects described herein, are provided. The methods may include using at least a first yarn type to knit a forefoot region and a midfoot region of an upper; a second yarn type may be used to knit a heel region and a first portion of an ankle collar located in the heel region, such that the second yarn type includes a greater number of elastically-resilient yarn ends compared to the first yarn type. In aspects, the forefoot region, the midfoot region, the heel region, and at least the first portion of the ankle collar may be integrally knit with each other to form a seamless construction. The uppers and articles of footwear described herein may further have a tongue-less construction such that an integrally knitted vamp may extend from the forefoot region to a topline edge of the ankle collar, e.g., to provide a more seamless, less delineated, and/or more simplified construction. In aspects, a vamp portion located adjacent to a topline edge may be knit with elastically-resilient yarns, among other possible yarns.

In aspects, a knitting process may include incorporating low-melting yarns in one or more regions or areas of an upper. For example, a low-melting yarn that includes a thermoplastic material, e.g., a thermoplastic polymeric composition, may be plated with a first yarn type in forefoot and/or midfoot regions of an upper. In aspects, a low-melting yarn that includes a thermoplastic material, e.g., a thermoplastic polymeric composition, may be plated with a second yarn type in a first portion of an ankle collar. In aspects, subsequent to knitting, heat may be applied to the upper to soften, partially melt, and/or melt the thermoplastic material of the low-melting yarns in the forefoot and midfoot regions, and the first portion of the ankle collar. Pressure may be applied to cause at least some flow, transfer, and/or disbursement of the thermoplastic material. Upon cooling, the thermoplastic material may re-solidify to form a thermoformed structure comprising the cooled thermoplastic material and other yarns knit with or adjacent to the low-melting yarn. In aspects, thermoformed structures in the forefoot region, the midfoot region, and/or the first portion of the ankle collar may provide structure, increase durability and/or rigidity, and reduce creasing, among other benefits.

In aspects, methods may further include integrating a collar elevator into a heel region of an upper. The collar elevator is adapted to shift at least partially downward from a first position to a second position in response to a downward force applied to the collar elevator from insertion of a foot through a foot-insertion opening of the upper. In addition, the collar elevator is configured to rebound upward to the first position in response to removal of the downward force. Methods may additionally include securing an upper to a sole structure to form an at least partially assembled article of footwear. The manufacturing processes described herein can occur in a different order than that described. For example, in some aspects, the upper may be secured to the sole structure before the collar elevator is integrated into the upper.

In accordance with references herein, an article of footwear and/or an upper may be divided into different general regions. For example, a forefoot region generally includes portions of the article of footwear and/or upper that corresponds to the toes and joints connecting the metatarsals with the phalanges; a midfoot region generally includes portions of the article of footwear and/or upper corresponding to an arch area and an instep area of the foot; a heel region generally corresponds to rear portions of the foot including the calcaneus bone. Uppers and articles of footwear described herein may include a lateral side, which corresponds with an outside area of the foot (e.g., the surface that faces away from the other foot), and a medial side, which corresponds with an inside area of the foot (e.g., the surface that faces toward the other foot). Uppers and articles of footwear described herein may also include a vamp that extends from the forefoot region or toe end to a topline edge of the upper and is configured to cover the instep area of the foot. The different regions and sides described in this section are intended to represent general areas of footwear to aid in the following discussion and are not intended to demarcate precise areas. The different regions and sides may be applied to the article of footwear as a whole, to the upper, and to the sole structure.

The uppers described herein can include an ankle collar that defines a foot-insertion opening into a foot-receiving cavity; the foot-receiving cavity includes a space that is occupied by a wearer’s foot when the article of footwear is worn. The ankle collar includes a topline edge. The term “outer-facing surface” refers to a surface of the upper or article of footwear that faces the external environment. In some aspects, the outer-facing surface can refer to the outermost-facing surface of the upper or article of footwear. The term “inner-facing surface” as used herein refers to a surface of the upper or article of footwear that faces a void for receiving the wearer’s foot. In some aspects, the inner-facing surface can refer to the innermost-facing surface of the upper or article of footwear.

The term “knit” as used herein, e.g., in connection with a knitted upper, refers to a textile piece that is formed from at least one yarn that is manipulated (e.g., with a knitting machine) to form a plurality of intermeshed loops (also known as interlooping) that define courses and wales. The term “course,” as used herein, refers to a predominantly horizontal row of knit loops (in an upright textile as it is knit on the knitting machine) that is produced by adjacent needles during the same knitting cycle. The course may include one or more stitch types, such as a knit stitch, a missed (float) stitch, a held stitch, a tuck stitch, a transfer stitch, a rib stitch, an ottoman rib stitch, and the like, as can be used in a knitting operation. The term “course-wise direction” refers to a direction that is parallel to the knit courses of a knit textile piece. The term “wale,” as used herein, is a predominantly vertical column of intermeshed or interlooped knit loops, generally produced by the same needle at successive (but not necessarily all) courses or knitting cycles. The term “wale-wise direction” refers to a direction that is parallel to the knit wales of the textile piece.

The term “single knit construction” refers to a single-layer knit construction generally formed on a single needle bed (e.g., a single-bed construction). In some examples, a single knit construction may be formed on a multi-bed knitting machine by knitting a number of knit courses on a first needle bed of the knitting machine and then transferring all of the loops to a second needle bed of the knitting machine where a number of knit courses are then knit, which may be repeated a number of times. In this way, even though two knitting beds are used, the resulting textile maintains a single knit construction. Common single knit constructions include single jersey. The term “double knit construction” as used herein refers to a knit construction that is generally formed on at least two needle beds of a knitting machine (e.g., a multi-bed construction). Multi-bed knit constructions may be characterized by two opposing faces or layers of knit loops and/or tucks, e.g., one face/layer of loops formed on a first needle bed (e.g., a first knit layer), and a second face/layer of loops formed on a second needle bed (e.g., a second knit layer). In example aspects, the two faces/layers may be joined by yarns that interloop with yarns in both the first face/layer and the second face/layer of the double knit construction (e.g., transfer yarns). However, aspects herein contemplate that the two faces/layers may not be joined or may be joined only along the sides such that a space or potential space is formed between the two faces/layers. Common double knit constructions include double jersey, rib, interlock, cardigan, other “double bed” knit structures initially formed on at least two needle beds, and other knit structures having two opposing faces/layers of knit loops or tucks, including full-gauge and less-than-full-gauge variations of those structures. In aspects, the uppers described herein, or portions thereof, may include a single knit construction and/or a double knit construction. The term “plating” or “plated” as used herein refers to a knitting technique in which two or more yarns (e.g., a low-melting yarn and a high-melting yarn) are fed through one feeder during the knitting process such that one yarn (e.g., the low-melting yarn) is positioned behind and/or adjacent to another yarn (e.g., the high-melting yarn) in the same knit loop. In aspects, multiple yarns of different constructions or materials can be plated together.

The term “integrally knit,” as used herein, refers to a knit textile having a yarn from one or more knit courses in a first area (e.g., a forefoot region) being interlooped with one or more knit courses of another area (e.g., a midfoot region). The interlooping may be through any of the stitch types discussed herein. In this way, areas that are integrally knit together have a generally seamless transition such that they generally seamlessly extend from one another. In an example according to aspects herein, the forefoot region, the midfoot region, the heel region, the vamp, and at least a portion of the ankle collar may be integrally knitted with each other.

Forming an article, e.g., an upper, using a knit construction may enable advantages including, but not limited to, a particular degree of elasticity (for example, as expressed in terms of Young’s modulus), breathability, bendability, strength, moisture absorption, weight, abrasion resistance, or a combination thereof. These characteristics may be provided by selecting a particular knit structure, changing a size and tension of the knit structure, by using one or more yarns formed of a particular material (e.g., a polyester material, a relatively inelastic material, or a relatively elastic material such as elasticated yarns, a thermoplastic material, and the like), by selecting yarns of a particular size (e.g., denier), or through some combination thereof. Using a knit construction may also provide desirable aesthetic characteristics by incorporating yarns having different colors, textures, or other visual properties arranged in a particular pattern. The yarns themselves and/or the knit structure formed by one or more of the yarns may be varied at different locations such that the upper may have different properties, as described herein.

The term “yarn type” as used herein refers to the composition of a particular yarn used to knit one or more areas or regions of a knitted component, e.g., forming part of an upper. The yarns described herein can include monofilament yarns and/or multifilament yarns formed from different materials or combinations of materials, including natural or synthetic materials. In aspects, yarns described herein can include a polymer material but may differ from other yarns at least in terms of melting temperature. The terms “high-melting” and “low-melting” as used herein are intended to be relative terms in that “low-melting” materials have a lower melting temperature than the melting or decomposition temperature of “high-melting” materials. For example, aspects herein may include high-melting yarns and low-melting yarns. High-melting polymer yarns may include, by way of example, yarns that melt at about 175 degrees Celsius or higher, including polyamide yarns (commonly known as nylon), PET yarns, recycled PET yarns, elastane yarns, and other high-melting synthetic yarns. In other examples, a high-melting yarn may include a yarn with natural fibers with a higher decomposition temperature (e.g., above 200 degrees Celsius). Low-melting yarns may comprise yarns with a polymer having a relatively low melting temperature (e.g., yarns that melt below 170 or 175 degrees Celsius), which may be a thermoplastic polymer material including thermoplastic elastomers such as thermoplastic polyurethane (TPU) and/or styrene ethylene/butylene styrene (SEBS).

Multifilament yarns, as described herein, may include filaments of the same material or different materials. In addition, a monofilament yarn may be a mono-component monofilament or may be a bicomponent monofilament. Mono-component monofilament yarns formed of a low-melting thermoplastic material, e.g., a thermoplastic polymeric composition, may be described herein as “fusible” yarns. Bicomponent monofilament yarns may have a first yarn component of a first material and a second yarn component of a second material with a lower melting temperature than the first material. The first yarn component may be in the form of a core, and the second yarn component may be in the form of a sheath surrounding the core, where the core and sheath may be extruded together, or the sheath may be a coating applied to the core.

In aspects, a melting temperature of a low-melting yarn and/or material can be sufficiently lower than a melting temperature of a high-melting yarn or material such that the low-melting component (e.g., a low-melting monofilament yarn) may be at least partially, or in some aspects fully, melted without melting or adversely affecting (e.g., burning, charring, or singeing) the characteristics of the high-melting yarn.

The term “thermoformed,” as used herein, refers to a structure modified at least in part through the application of heat and/or pressure. In aspects, thermoforming includes heating and applying pressure to softened, partially melted, and/or melted thermoplastic material of one or more low-melting yarns to then form a thermoformed structure upon cooling and re-solidifying of the thermoplastic material. Thermoformed structures can include the same thermoplastic material as the thermoplastic material used to form at least part of a low-melting yarn (e.g., TPU, SEBS, TPE, and the like). When low-melting yarns are entirely formed from a low-melting thermoplastic material (e.g., fusible yarns), the thermoformed structure may include only the cooled thermoplastic material and, if present, any other yarns knit with or adjacent to the low-melting yarn. When low-melting yarns include a core/sheath configuration, the thermoformed structure may include the cooled thermoplastic material and the core portion of the low-melting yarns (as well as any other yarns knit with or adjacent to the low-melting yarn, if present). Any and all aspects, and any variation thereof, are contemplated as being within the scope herein.

The term “yarn end,” as used herein, refers to a strand (either multifilament or monofilament) of yarn. In aspects, any number of ends (e.g., one end, two ends, three ends, four ends, and the like) may be joined together to form a yarn that is used to knit the knitted components and uppers described herein. Yarn ends may be joined together by twisting, bonding, melting, or another type of mechanical, frictional, or chemical joining. If a yarn contains more than one yarn end, the yarn ends may be the same composition (e.g., all PET yarn ends) or the yarn ends may have different compositions (e.g., a PET yarn end[s] and an elastane yarn end[s]).

The term “elastic yarn” or “elastically resilient yarn” as used herein refers to yarns (e.g., spandex, elastane, and the like) that stretch or deform in response to an applied force and return to their resting state or resting length once the applied force is removed. In example aspects, the yarns may stretch from about 100% to 200% of their resting length. Similarly, the term “elastic deformation” when describing, for example, the collar elevator, means a temporary and reversible change in length, volume, or shape produced in an elastic substance by a stress or applied force that is less than the elastic limit of the substance. The elastic substance returns to its original length, volume, and/or shape when the deforming force is removed.

Unless indicated otherwise, all measurements provided herein are taken when the upper and/or article of footwear is at standard ambient temperature and pressure (298.15 K and 100 kPa) and is in a resting (non-tensioned) state.

FIG. 1 depicts a view of a first side (e.g., a medial side or a lateral side) of an article of footwear 100. FIG. 2 depicts a top-down view of the article of footwear 100. FIG. 3 depicts a rear view of the article of footwear 100. It should be understood that a view of an opposite second side of the article of footwear 100 would be generally similar to FIG. 1. As depicted in FIGS. 1-3, the article of footwear 100 is intended to be used with a left foot; however, it should be understood that the following discussion may also apply to a mirror image of the article of footwear 100 that is intended for use with a right foot. Although an article of footwear is shown, it should be understood that some aspects of the present disclosure can be incorporated into other articles, including but not limited to apparel (e.g., shirts, jerseys, pants, shorts, gloves, glasses, socks, hats, caps, jackets, undergarments, or other apparel) and containers (e.g., backpacks, bags, or other containers). Furthermore, although the article of footwear 100 is depicted as an athletic shoe, aspects herein contemplate that the disclosed aspects may also be applied to other shoe types such as loafers, sandals, slippers, hiking shoes, and the like.

The article of footwear 100 includes an upper 110 secured to a sole structure 112 at a biteline 111. The sole structure 112 extends between a wearer’s foot and the ground when the article of footwear 100 is worn and may optionally include a plurality of ground-engaging cleats (not shown). The upper 110 generally defines a foot-receiving cavity within the upper 110 for receiving and securing a wearer’s foot relative to the sole structure 112. The surfaces of the foot-receiving cavity within the upper 110 are shaped to accommodate the foot and may extend over the instep and toe areas of the foot, along the medial and lateral sides of the foot, under the foot, and around the heel area of the foot.

The article of footwear 100 includes a forefoot region 114, a midfoot region 116, a heel region 118, a toe end 119, and a heel end 121. The heel region 118 is generally demarcated by a dashed line 123 as shown in FIG. 1. The upper 110 includes an ankle collar 126 that at least partially defines a foot-receiving opening 130 for receiving a wearer’s foot into the foot-receiving cavity. The ankle collar 126 includes a topline edge 128 (e.g., an uppermost edge). In example aspects, the ankle collar 126 includes different portions, e.g., a first portion 136 (indicated with hatching) located in the heel region 118. In aspects, at least a first portion 136 of the ankle collar 126 is a substantially seamless extension of the heel region 118. The first portion 136 of the ankle collar 126 may extend about 0.25 cm to about 2 cm from the topline edge 128 toward the sole structure 112.

In example aspects, the upper 110 can include a tongue-less construction. As best shown in FIG. 2, the upper 110 includes a vamp 124 that extends from the forefoot region 114 to the topline edge 128. More specifically, the vamp 124 extends generally from the toe end 119 to generally the topline edge 128. In addition, a vamp portion 134 located adjacent to the ankle collar 126 may include a different yarn type compared to remaining portions of the vamp 124, as further described below. In examples, the vamp portion 134 may extend from about 0.5 cm to about 15 cm from the topline edge 128 toward the toe end 119.

In example aspects, at least a portion of the upper 110 may be formed from at least one knit textile 132, as indicated by the knit loops in FIGS. 1 and 3. In aspects, the knit textile 132 may be formed by a weft-knitting process on a flat knitting machine or it may be formed by a warp-knitting process. The knit textile 132, or portions thereof, may include a single knit construction and/or may include a double knit construction. The knit textile 132 may be formed as a single, integral one-piece element during a knitting process, such as weft knitting, warp knitting, or any other suitable knitting process. In this example, the forefoot region 114 of the upper 110, the midfoot region 116 of the upper 110, the heel region 118 of the upper 110, the vamp 124, the vamp portion 134, and at least the first portion 136 of the ankle collar 126 may be integrally knit with each other to form a substantially seamless construction. The use of a seamless construction may help reduce manufacturing time and may help reduce or limit areas subject to structural weakness, e.g., seam areas. In the example depicted in FIGS. 1-3, the knit textile 132 forms at least an outer sheath or covering of the upper 110 such that it forms an outer-facing surface of the article of footwear 100. In some aspects, the knit textile 132 further forms an interior surface of the upper 110.

Looking now at FIG. 4, a top-down depiction of the upper 110 after the upper 110 comes off of a knitting machine is shown, in accordance with aspects herein. FIG. 4 generally shows the upper 110 being represented as a one-piece integrally knit structure. The different regions of the upper 110 are indicated by dashed lines and include the medial and lateral forefoot regions 114a and 114b, the medial and lateral midfoot regions 116a and 116b, the medial and lateral heel regions 118a and 118b, the first portion 136 of the ankle collar 126, the vamp 124, and the vamp portion 134. The different regions and portions of the upper 110 are shown as generally being symmetrical on the medial and lateral sides of the upper 110, although aspects herein contemplate that the different regions and portions of the upper 110 may not be symmetrical. The upper 110 in FIG. 4 further includes heel edge 410a and heel edge 410b. When the upper 110 is assembled into the article of footwear 100, the heel edges 410a and 410b may be joined together to form a heel seam 310 (seen in FIG. 3) located at the heel end 121 of the upper 110. The depiction of the upper 110 in FIG. 4 is illustrative and other configurations of the knit upper 110 are contemplated herein, including configurations that include an underfoot portion, configurations having edges of the upper joined together at locations other than the heel end 121 (e.g., in the midfoot region 116 or the forefoot region 114), and the like.

In aspects, the forefoot region 114 and the midfoot region 116 may be knit using at least a first yarn type. In examples, the first yarn type may be a high-melting yarn having a higher tenacity (e.g., at least 4, at least 5, or at least 6 grams per denier, in aspects) suitable for resisting abrasion forces. One such example is a PET yarn including a recycled PET yarn. In one example, the first yarn type may include two or more ends (e.g., two ends, three ends, or four ends) of a yarn (e.g., a PET yarn) twisted together. In aspects, the first yarn type does not include any ends of an elastically resilient yarn such as elastane. In aspects, the first yarn type may additionally include one or more ends of an elastically resilient yarn such as one end, two ends, or three ends.

In the forefoot region 114 and/or in the midfoot region 116, the first yarn type may be plated with a low-melting yarn during the knitting process, e.g., a low-melting mono-component monofilament yarn that includes a thermoplastic material, e.g., a thermoplastic polymeric composition such as a thermoplastic elastomer (e.g., a fusible yarn). This optional configuration is generally depicted in FIG. 5A, which shows an example of a high-melting yarn type 510 plated with a low-melting yarn 512. In aspects, after the upper 110 is knitted, heat and/or pressure may be applied to the upper 110, where the temperature is sufficient to soften, partially melt, and/or fully melt the low-melting yarn 512. In addition, applied pressure can at least partially cause some flow of the melted thermoplastic elastomer. As schematically depicted in FIG. 5B, when the thermoplastic elastomer re-solidifies, a thermoformed structure 514 is formed that includes and/or defines a thermoformed network of interlooped yarns. The thermoformed structure 514 in FIG. 5B depicts the melted, re-flowed, and re-solidified thermoplastic elastomer and the high-melting yarns 510. In FIG. 5B, the thermoformed structure 514 is shown as substantially fully encasing the high-melting yarn 510. However, aspects herein contemplate that one or more portions of the high-melting yarn may not be embedded within the thermoformed structure 514.

The thermoformed structure 514 can be incorporated into the forefoot region 114 and/or into the midfoot region 116 without elastically resilient yarn ends being present, and this configuration can provide structure and/or a degree of rigidity to these areas. Described differently, where implemented, the thermoformed structure 514 may help to lock the knit loops into place and thereby help reduce mechanical stretching when a force is applied to the knit structure. The limited to substantially no stretch in the forefoot region 114 and/or the midfoot region 116 due to the absence or reduced amount of elastically resilient yarn ends in combination with the thermoformed structure 514 may provide beneficial containment for a wearer’s foot, may help to prevent the forefoot and midfoot regions 114 and 116 from collapsing during the shoe-donning process, and may limit shifting of the wearer’s foot during wear including during athletic wear. As further described below, this may help contribute to the easy donning features of the article of footwear 100.

In example aspects, the heel region 118 may be knit with a second yarn type that includes a greater number of elastically resilient yarn ends compared to the first yarn type. In aspects, the heel region 118 may not include any low-melting yarns comprising a thermoplastic polymer material, e.g., thermoplastic polymeric composition such as a thermoplastic elastomer. Omitting or substantially omitting the low-melting yarn ends from at least part of the heel region 118 may cause the heel region 118 to be more flexible or pliable. The resulting increased pliability of the heel region 118 may facilitate the heel region 118 folding, bending, and/or compressing downward during donning of the article of footwear 100.

In aspects, the second yarn type may also include one or more ends of a high-melting, non-elastically resilient yarn having relatively higher tenacity and abrasion-resistant characteristics, e.g., PET yarns including recycled PET yarns. In one example, the second yarn type is a twisted yarn comprising PET and elastane. In an aspect, the second yarn type may include four or more ends of PET twisted with four or more ends of elastane. This is an example, and other twisted yarn configurations including those with one or more non-elastically-resilient yarn ends and one or more elastically-resilient yarn ends are contemplated herein. In another example, the elastically-resilient yarn ends may not be combined with the non-elastically resilient yarn ends in a twisted configuration. In this example, the elastically-resilient yarn ends may be introduced into the heel region using a first feeder of a knitting machine, and the PET yarn ends may be introduced into the heel region using a second feeder of the knitting machine. The use of a twisted yarn compared to using two separate yarns may improve manufacturing efficiency due to only having to thread one feeder compared to two feeders. In addition, using a twisted yarn may decrease yarn shrinkage in an elastane yarn compared to using an elastane yarn by itself, as the non-elastically resilient yarn ends may help to “lock” the elastically resilient yarn ends into place. As described below, the use of elastically resilient yarn ends in the heel region 118 may contribute to the easy donning features and characteristics of the article of footwear 100.

Potential shrinkage in the heel region due to the use of elastane in a twisted yarn or using elastane by itself may be accommodated by increasing the volume of material in the heel region 118. In one example, this may be done by increasing the number of courses per centimeter as measured in the wale-wise direction compared to the number of courses per centimeter in the wale-wise direction in the midfoot region 116 and/or in the forefoot region 114. In another example, the volume of material may be increased by making the courses longer in the heel region 118 (e.g., adding needles to increase the length of the courses in the heel region 118).

In example aspects, the second yarn type may also be used to knit the first portion 136 of the ankle collar 126. In the first portion 136 of the ankle collar 126, the second yarn type may be plated with a low-melting yarn that includes a thermoplastic material, e.g., a thermoplastic polymeric composition, e.g., a thermoplastic elastomer. Similar to what was described in connection with FIGS. 5A and 5B, after the first portion 136 is knitted, one or more of heat and pressure may be applied to the upper 110, causing the low-melting yarns to soften, partially melt, and/or melt. The pressure may cause at least some flow of the melted thermoplastic material. Upon re-solidifying, the thermoformed structure 514 is then formed. In aspects, the additional structure and/or rigidity in the first portion 136 of the ankle collar 126 may serve a number of different purposes. For example, the enhanced structure in this area may be beneficial, as this area may be subject to repeated downward pressure from the bottom of a wearer’s foot as they press down on the heel region 118 when donning the article of footwear 100. In addition, the structure in the first portion 136 may decrease wrinkles or creasing over continued use, which enhances the aesthetic appeal of the article of footwear 100. The increased structure in the first portion 136 may also facilitate the assembly of the article of footwear 100 by minimizing folding of the material of the upper 110 during shoe assembly.

In aspects, one or more portions of the vamp 124 including the vamp portion 134 may be knit with elastically resilient yarns, e.g., elastane. In some examples, the vamp portion 134 may be knit using solely elastically-resilient yarns. In other aspects, the vamp portion 134 can be knitted from a combination of different yarns. The use of elastically-resilient yarns in the vamp portion 134, including substantially exclusively elastically-resilient yarns, can help facilitate easy donning of the article of footwear 100.

FIGS. 6A and 6B again depict the article of footwear 100 additionally depicting a collar elevator incorporated therein, in accordance with aspects herein. In particular, FIGS. 6A and 6B depict the article of footwear 100 with an example collar elevator 610 incorporated therein. FIG. 6A depicts the article of footwear 100 with the upper 110 shown in ghosted lines in order to better depict the collar elevator 610. The collar elevator 610 is coupled to the upper 110 in the heel region 118 and is adapted to shift the ankle collar 126 from a first or elevated position, as shown in FIG. 6A, to a second or lowered position, as shown in FIG. 6B (more positions are possible depending on the range of motion of the collar elevator 610, and these are examples). More specifically, the example collar elevator 610 may include portions that are integrated into the heel region 118 and that extend up to or adjacent to the ankle collar 126. Described differently, the collar elevator 610 extends from a more inferior part closer to the sole structure 112 to a more superior part closer to the ankle collar 126. The collar elevator 610 may be coupled to the upper 110 in the heel region 118, to the ankle collar 126, or to any and all combinations thereof. The collar elevator 610 shown in FIGS. 6A and 6B is an example of just one type of collar elevator adapted to shift an ankle collar (e.g., the ankle collar 126) from the second or lowered position to the first or elevated position, e.g., in response to a force 615. The collar elevator as described herein may include one or more alternative structures than those depicted in FIGS. 6A and 6B.

In example aspects, the collar elevator 610 may be affixed at least partially or entirely between an exterior layer of the upper 110 and an inner lining layer in the heel region 118, in the ankle collar 126, or any and all combinations thereof. In another aspect, the collar elevator 610 may be at least partially exposed and arranged on an exterior surface of the upper 110. In this aspect, the collar elevator 610 might be attached to the heel region 118 and/or to the ankle collar 126 by a tab, a bonding agent, stitch(es), or another form of mechanical or material coupling. In another or additional aspect, at least a portion of the collar elevator 610 may be exposed on the inside, foot-facing surface of the upper 110. Any and all aspects, and any variation thereof, are contemplated as being within the scope herein.

In some aspects herein, a collar elevator, e.g., like the collar elevator 610, can be formed of a material that is elastically deformable, e.g., a plastic, polymer, rubber, composite material, or combination thereof. Thus, when depressed by a force, the collar elevator can change shape, deforming from a non-deformed shape into a deformed and/or compressed shape, e.g., through bending of the elastically deformable material. The deformation of the material stores potential energy, which allows the collar elevator to then rebound to the original resting shape once the force is removed.

In some aspects herein, a collar elevator, e.g., like the collar elevator 610, can be formed with one or more mechanical pivot mechanisms, e.g., that include mechanical components that are capable of pivoting relative to each other. For example, looking at FIG. 6A, the collar elevator 610 could include a pivot mechanism 619 with a pair of pivotable hinges 620a and 620b. The pivotable hinges 620a and 620b can be biased, e.g., spring-biased using rotational springs or other biasing elements, towards the position shown in FIG. 6A, such that when the collar elevator 610 is depressed by a force, the pivotable hinges 620a and 620b of the pivot mechanism 619 rotate against the biasing force into a more compressed configuration similar to that shown in FIG. 6B. This rotation of the components and compression of the mechanism stores potential energy that allows the collar elevator to then rebound to the original configuration shown in FIG. 6A once the force is removed.

Looking again at FIGS. 6A and 6B, the example collar elevator 610 may include various elements that support the collar elevator’s function and structure. For example, in the depicted aspect, the collar elevator 610 includes a medial lever arm 612, a lateral lever arm 614, and a center connecting band 616 that couples the medial lever arm 612 and the lateral lever arm 614 and that is located adjacent to or approximately at the ankle collar 126. In a further aspect, the medial and lateral lever arms 612 and 614 may be affixed to a base 618, which remains stationary relative to the lever arms 612 and 614 as the lever arms 612 and 614 deform when the ankle collar 126 is moved to the second or lowered position by the force 615, as shown in FIG. 6B. In some example aspects, the base 618 may be a portion of the article of footwear 100, such as a portion of the sole structure 112 or a portion of the upper 110. In another example, and as shown in FIGS. 6A and 6B, the base 618 may be one or more other anchors or structures affixed directly or indirectly to the sole structure 112. In general, the base 618 can be a relatively rigid or fixed portion to which the lever arms 612 and 614 are anchored, allowing them to deform or pivot relative to the base 618.

In some aspects, the medial and lateral lever arms 612 and 614 may be directly coupled, mounted, or attached to the base 618. In other aspects, the base 618 may include one or more anchors that engage and retain the medial and lateral lever arms 612 and 614 in place on the base 618. For example, anchors may be located at a junction between the lever arms 612 and 614 and the base 618. Such anchors might be integrally formed with, coupled to, and/or located within or between or outside of portions of the sole structure 112 (e.g., insole, midsole, or outsole). For example, an anchor may be disposed in a block, plate, or wedge layered among, on top, or beneath the sole structure 112. In some instances, a portion of the sole structure 112 (e.g., midsole) might be carved or cut out to attach to or house an anchor. In another aspect, the base 618 may include an anchor-shaped receptacle into which an anchor engages by way of a resistance fit, compression fit, a snap fit, or via an interlocking mechanism/configuration. In other examples, the anchors may be integrally formed with, coupled to, and/or located within, between, or outside of portions of the upper 110.

The pivoting of the medial and lateral lever arms 612 and 614 can be provided via different configurations. In some aspects, optionally, the medial and lateral lever arms 612 and 614 can be pivotably coupled to the base 618, e.g., at pivoting anchors 621a and 621b, such that the medial and lateral lever arms 612 and 614 and the center connecting band 616 can pivot substantially in unison about the pivoting connections on the base 618. In some aspects, optionally, each of the medial and lateral lever arms 612 and 614 can include a corresponding pivoting element thereon, e.g., the pivotable hinges 620a and 620b, that allows an upper portion of the medial and lateral lever arms 612 and 614 and the attached center connecting band 616 to rotate about the pivotable hinges 620a and 620b. Other configurations, e.g., including the use of elastically-deformable materials and components, in addition or in the alternative to the aforementioned configurations, are contemplated herein.

In one aspect, the medial lever arm 612, the lateral lever arm 614, and the center connecting band 616 may be a single continuous body, such that clear demarcation may not exist between the medial lever arm 612, the lateral lever arm 614, and the center connecting band 616. For example, the medial and lateral lever arms 612 and 614 and the center connecting band 616 may be molded, cast, 3D-printed, or otherwise formed as a single, integrally formed structural piece. In other aspects, the medial lever arm 612 and the lateral lever arm 614 may be discrete, separate, and distinct elongated members, which are connected to the center connecting band 616, such as by a mechanical coupling, adhesive coupling, a friction fit, male-female connection, sheathing, or other coupling. In other examples, the collar elevator 610 may not include the center connecting band 616. The depiction of the collar elevator 610 in FIGS. 6A and 6B is illustrative, and other example configurations are contemplated herein.

The collar elevator 610 allows the ankle collar 126 to shift from the second or lowered position (shown in FIG. 6B) to the first or elevated position (shown in FIG. 6A). More specifically, at least a portion of the medial lever arm 612, the lateral lever arm 614, the center connecting band 616, or any combination thereof, is affixed or at least partially coupled to a portion of the upper 110 (e.g., a textile thereof or frame thereof). In one aspect, the center connecting band 616 may be affixed near or at the first portion 136 of the ankle collar 126. For example, the center connecting band 616 may be attached to the first portion 136 of the ankle collar 126 by an adhesive, connection tab, stitch, or the like. Thus, when the ankle collar 126 is shifted downward from the first position to the second position, the medial lever arm 612 and the lateral lever arm 614 can reversibly shift or deform to a more compressed and/or more loaded position. Stated differently, the collar elevator 610 stores potential energy by pivoting (against a biasing force) or elastically deforming from a less compressed configuration (first position) to a more compressed configuration (second position) when a downward force shifts the ankle collar 126 from the first position to the second position. The potential energy is able to rebound the collar elevator 610 back to the first position upon removal of the downward force.

In some aspects, and as described herein, the collar elevator 610 is adjustable but has a bias to move towards a non-bent or uncompressed configuration. The collar elevator 610 may include one or more of a tube, a wire, a spring, a shape memory structure or material, and the like, to facilitate this bias. In aspects, depending on the configuration that enables shifting in response to a force, the collar elevator 610 can include one or more materials such as carbon steel, stainless steel, titanium, nickel titanium (nitinol) and/or other metals and alloys (shape-memory or otherwise), polymers (shape-memory or otherwise), composite materials, foam materials, graphite, carbon fiber, fiberglass, thermoplastic polyester elastomers (TPC-ET), silicone, thermoplastic polyurethane (TPU), and polycarbonate. For example, in aspects, the collar elevator 610 may include titanium or may be a titanium wire. Also, one or more elements of the collar elevator 610 (e.g., the medial lever arm 612) may be made of a first material (e.g., titanium) and one or more additional elements of the collar elevator 610 (e.g., the lateral lever arm 614) may be made of a second material (e.g., graphite).

Properties of the knit textile 132 that form at least part of the upper 110 as described herein may work in combination with the collar elevator 610 to provide an easier, more hands-free, smoother donning experience. For example, the article of footwear 100 may be slipped on by a wearer with reduced reliance on extremities or shoe-donning tools, e.g., potentially aiding users with disabilities or other physical limitations that otherwise have difficult with such actions. FIG. 7A depicts a wearer’s foot 710 being inserted into the foot-receiving opening 130 of the upper 110 of the article of footwear 100. The arch or heel of the wearer’s foot 710 is pressing down on at least the first portion 136 of the ankle collar 126, which causes the collar elevator 610 (shown in a dashed lined) to resiliently compress at least partially downward towards the sole structure 112. This movement also temporarily expands the topline edge 128 making the foot-receiving opening 130 larger to allow for easier insertion of the wearer’s foot 710. Due to the presence of the thermoformed structure 514 in the first portion 136 of the ankle collar 126, this area is better able to withstand the compressive or downward forces of the wearer’s foot. This can help reduce or limit degradation of the materials at the heel, as well as reduce or limit creasing, wrinkling, breaking, or fraying of textile yarns.

FIG. 7A shows that as the collar elevator 610 is depressed downward and/or rearward, at least a portion of the heel region 118 moves downwardly toward the biteline 111 and/or the sole structure 112. The downward movement of the heel region 118 may be due, at least in part, to the pliability of the knit textile 132 in this region, e.g., due to the absence of or reduction of the thermoformed structure 514. Stated differently, omitting, at least partially or substantially fully, low-melting yarns including a thermoplastic polymeric composition in the heel region 118 supports greater pliability in this area. The downward movement of the heel region 118 causes the elastically resilient yarns in the heel region 118 to be resiliently stretched. As such, both the collar elevator 610 and the heel region 118 are configured to store potential energy in the second position shown in FIG. 7A. As described below with respect to FIG. 7B, the stored potential energy is used to return the heel region 118 and the collar elevator 610 to the first or elevated position once the wearer’s foot 710 is fully inserted within the article of footwear 100.

In addition, as shown in FIG. 7A, as the wearer is inserting their foot 710 into the article of footwear, the vamp 124 and particularly the vamp portion 134 may stretch to accommodate the wearer’s instep, e.g., due to at least the vamp portion 134 incorporating elastically-resilient yarns. The presence of elastically-resilient yarns in the vamp portion 134 and/or other adjacent areas enables this portion to expand, making the shoe-donning process easier and smoother, among other benefits.

The inclusion of the thermoformed structure 514 in the forefoot region 114 and/or in the midfoot region 116 of the upper 110 in combination with the absence (or relative reduction) of elastically-resilient yarns in these areas may help to inhibit the forefoot and/or midfoot regions 114 and 116 from collapsing, compressing, and/or compacting during the shoe-donning process, thereby easing the donning process. For example, a higher rigidity in these regions can help the regions maintain an upright configuration when the wearer is inserting their foot 710 into the article of footwear 100, which makes the shoe-donning process easier.

FIG. 7B depicts the article of footwear 100 after the wearer’s foot 710 is inserted substantially fully within the foot-receiving cavity. The stored potential energy from the elastically deformable collar elevator 610 in combination with the stored potential energy in the heel region 118 due to the presence of the stretched elastically-resilient yarns causes the collar elevator 610 and the heel region 118 to generally rebound upward to the first or elevated position once the wearer’s foot 710 is fully inserted within the foot-receiving cavity of the article of footwear 100.

The use of elastically-resilient yarns in the heel region 118 can help provide a more secure and generally compressive or restrictive fit around the heel area of the wearer, which may facilitate wearer comfort and provide support to the wearer’s Achilles tendon area. Once the wearer has fully inserted his or her foot 710 into the foot-receiving cavity, the elastically-resilient yarns in the vamp portion 134 can generally return to their resting length. The vamp portion 134 further secures the wearer’s foot 710 within the article of footwear 100.

FIG. 8 depicts a block diagram of an example method 800 of manufacturing an article of footwear, e.g., the article of footwear 100, in accordance with aspects herein. In block 810, a first yarn type is used to knit at least a forefoot region, such as the forefoot region 114 in FIG. 1, and a midfoot region, such as the midfoot region 116 in FIG. 1, of an upper, such as the upper 110 in FIG. 1. In example aspects, the first yarn type may be a high-melting yarn that has higher tenacity (e.g., between about 3-10 grams per denier) and resistance to abrasion such as a PET yarn type including a recycled PET yarn type. In some aspects, the first yarn type may be plated with a low-melting yarn that includes a thermoplastic polymer material, e.g., a thermoplastic polymeric composition such as a thermoplastic elastomer. After knitting, one or more of heat and pressure may be applied to the upper causing the low-melting yarns to soften, partially melt, or fully melt and then flow, distribute, disburse, and/or spread around other yarns and/or spaces therebetween. Upon the thermoplastic polymeric composition re-solidifying, a thermoformed structure, such as the thermoformed structure 514, is formed in the forefoot region and the midfoot region, which imparts a degree of rigidity to these areas. In some aspects, the first yarn type does not include any elastically resilient yarn ends.

In block 812, a second yarn type is used to knit a heel region, such as the heel region 118 of the upper 110 shown in FIG. 1. In example aspects, the second yarn type has a greater number of elastically resilient yarn ends than the first yarn type. In one example, the second yarn type may comprise a twisted yarn of PET yarn ends and elastane yarn ends. In another example, the elastane yarn ends may be introduced by a first feeder and the PET yarn ends may be introduced by a second feeder. In example aspects, the heel region may not include any low-melting yarns, including a thermoplastic polymeric composition such as a thermoplastic elastomer. The substantial absence of the low-melting yarns in this area contributes to the pliability/flexibility of the heel region.

In examples, the second yarn type may also be used to knit a first portion of an ankle collar located in the heel region, such as the first portion 136 shown in FIG. 1. In this aspect, a low-melting yarn that includes a thermoplastic polymer material, e.g., thermoplastic polymer composition such as a thermoplastic elastomer, may be plated with the second yarn type in the first portion of the ankle collar. After knitting, one or more of heat and pressure may be applied to the upper causing the low-melting yarns to soften, partially melt, or fully melt and then flow, distribute, disburse, and/or spread around other yarns and/or spaces therebetween. Upon the thermoplastic polymer material re-solidifying, a thermoformed structure is formed in the first portion, which imparts a degree of rigidity to this areas. The degree of rigidity may help provide a stable base for which a wearer’s foot can exert pressure during the shoe-donning process. Moreover, the degree of rigidity may help prevent this area from breaking down during repeated use and may also help to reduce wrinkling or creasing, which enhances the aesthetic appeal of the article of footwear.

In block 814, a collar elevator, such as the collar elevator 610 shown in FIGS. 6A and 6B, including variations thereof described in connection with FIGS. 6A and 6B, is integrated into the heel region. The collar elevator can be formed of an elastically-deformable material such that the collar elevator is operable to move at least partially downward from a first or elevated position to a second or lowered position in response to a downward force that occurs by way of insertion of a wearer’s foot through a foot-insertion opening of the upper. Because the collar elevator is elastically-deformable, the collar elevator rebounds upward to the first or elevated position upon removal of the downward force.

In block 816, the upper is secured to a sole structure, such as the sole structure 112 shown in FIG. 1. The use of elastically-resilient yarn ends in the heel region contributes to the easy donning features of the article of footwear. For example, when a downward force is applied to the first portion of the ankle collar, the heel region moves downwardly toward the sole structure, which, in turn, stretches the elastically resilient yarn ends. The stretched elastically-resilient yarn ends store potential energy such that when the downward force is removed, the heel region returns to its elevated position.

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

Clause 1. An article of footwear comprising: a sole structure; a knitted upper secured to the sole structure proximate a biteline, the knitted upper comprising a forefoot region, a midfoot region, a heel region, and an ankle collar defining a perimeter around a foot-insertion opening into a foot-receiving cavity, the ankle collar comprising a topline edge, wherein: the forefoot region and the midfoot region are knit with at least a first yarn type, and the heel region is knit with a second yarn type different than the first yarn type, the second yarn type comprising a greater number of elastically resilient yarn ends compared to the first yarn type; and a collar elevator integrated at least partially into the heel region, the collar elevator adapted to shift at least partially downward from a first position to a second position in response to a downward force applied to the collar elevator from insertion of a foot through the foot-insertion opening, and rebound upward to the first position in response to removal of the downward force, wherein the foot-insertion opening temporarily expands when the collar elevator is in the second position.

Clause 2. The article of footwear according to clause 1, wherein at least a portion of the ankle collar in the heel region is knit with the second yarn type and one or more low-melting yarns.

Clause 3. The article of footwear according to clause 2, wherein the one or more low-melting yarns are plated with the second yarn type.

Clause 4. The article of footwear according to any of clauses 1 through 3, wherein the collar elevator and at least a portion of the heel region are configured to store potential energy as the collar elevator moves from the first position to the second position, and wherein the collar elevator and the portion of the heel region are configured to be returned to the first position by way of the stored potential energy.

Clause 5. The article of footwear according to clause 4, wherein, upon the application of the downward force during insertion of the foot, the portion of the heel region moves downwardly toward the biteline.

Clause 6. The article of footwear according to any of clauses 1 through 5, wherein in the forefoot region and the midfoot region of the knitted upper, the first yarn type is plated with one or more low-melting yarns.

Clause 7. The article of footwear according to any of clauses 1 through 6, wherein the first yarn type comprises zero elastically resilient yarn ends.

Clause 8. The article of footwear according to any of clauses 1 through 7, wherein the heel region does not include low-melting yarns.

Clause 9. The article of footwear according to any of clauses 1 through 8, wherein the second yarn type comprises a twisted yarn comprising polyethylene terephthalate yarns ends and elastane yarn ends.

Clause 10. The article of footwear according to any of clauses 1 through 9, wherein the first yarn type comprises one or more polyethylene terephthalate yarn ends.

Clause 11. The article of footwear according to any of clauses 1 through 10, wherein the knitted upper is tongue-less and comprises a vamp extending from the forefoot region to the topline edge.

Clause 12. An article of footwear comprising: a sole structure; an upper secured to the sole structure, the upper comprising a forefoot region, a midfoot region, a heel region, an ankle collar defining a perimeter around a foot-insertion opening into a foot-receiving cavity, the ankle collar comprising a topline edge, and a vamp extending from the forefoot region to the topline edge, wherein: the forefoot region, the midfoot region, the heel region, the ankle collar, and the vamp are integrally knit with each other, the forefoot region and the midfoot region are knit with at least a first yarn type, and the heel region and at least a portion of the vamp are knit with a greater number of elastically resilient yarn ends compared to the first yarn type; and a collar elevator integrated at least partially into the heel region, the collar elevator adapted to shift at least partially downward from a first position to a second position in response to a downward force applied to the collar elevator from insertion of a foot through the foot-insertion opening, and rebound upward to the first position in response to removal of the downward force, wherein the foot-insertion opening temporarily expands when the collar elevator is in the second position.

Clause 13. The article of footwear according to clause 12, wherein the heel region is knit with a second yarn type different from the first yarn type.

Clause 14. The article of footwear according to clause 13, wherein the second yarn type comprises a twisted yarn comprising polyethylene terephthalate yarns ends and elastane yarn ends.

Clause 15. The article of footwear according to any of clauses 13 through 14, wherein at least a portion of the ankle collar in the heel region is knit with the second yarn type and one or more low-melting yarns.

Clause 16. The article of footwear according to clause 15, wherein the one or more low-melting yarns are plated with the second yarn type.

Clause 17. The article of footwear according to any of clauses 12 through 16, wherein the collar elevator and at least a portion of the heel region are configured to store potential energy as the collar elevator moves from the first position to the second position, and wherein the collar elevator and the portion of the heel region are configured to be returned to the first position by way of the stored potential energy.

Clause 18. The article of footwear according to any of clauses 12 through 17, wherein in the forefoot region and the midfoot region of the upper, the first yarn type is plated with one or more low-melting yarns.

Clause 19. The article of footwear according to any of clauses 12 through 18, wherein the heel region does not include low-melting yarns.

Clause 20. A method of manufacturing an article of footwear, the method comprising: using at least a first yarn type to knit a forefoot region and a midfoot region of an upper; using a second yarn type to knit a heel region of the upper and at least a portion of an ankle collar located in the heel region, the second yarn type comprising a greater number of elastically resilient yarn ends compared to the first yarn type; integrating a collar elevator at least partially in the heel region, the collar elevator adapted to shift at least partially downward from a first position to a second position in response to a downward force applied to the collar elevator from insertion of a foot through the foot-insertion opening, and rebound upward to the first position in response to removal of the downward force, wherein the foot-insertion opening temporarily expands when the collar elevator is in the second position.

Aspects of the present disclosure have been described with the intent to be illustrative rather than restrictive. Alternative aspects will become apparent to those skilled in the art that do not depart from its scope. A skilled artisan may develop alternative means of implementing the aforementioned improvements without departing from the scope of the present disclosure.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations and are contemplated within the scope of the claims. Not all steps listed in the various figures need be carried out in the specific order described.