KNIT ELEMENT WITH CUSHIONING AND RIGIDITY ZONES, UPPERS AND FOOTWEAR WITH THE SAME, AND METHODS OF MANUFACTURING THE SAME

TECHNICAL FIELD

The field relates to knit elements, including knit heel elements, used in footwear.

BACKGROUND

Traditional heel elements, which may broadly be defined as an element that gives structure, cushion, and/or support to a heel area of an upper for an article of footwear, typically are formed from rigid or semi-rigid materials such as leather, plastic, or the like. Moreover, traditional heel elements are typically attached to an outer-facing surface of an upper during a manufacturing process. In instances where heel elements include cushioning, such as adjacent to a collar area of an upper, a cushioning element is generally secured to the heel element in an additional manufacturing step. Besides increasing time and expense associated with manufacturing an article of footwear, these additional manufacturing steps may increase the overall carbon footprint associated with footwear manufacturing, which is not desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of aspects herein are described in detail below with reference to the attached drawing figures, wherein:

FIG. 1 illustrates a medial view of an example article of footwear with a knit heel element, in accordance with aspects herein;

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

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

FIG. 4A illustrates one configuration of a knit heel element, in accordance with aspects herein;

FIG. 4B illustrates another configuration of a knit heel element similar to FIG. 4A, in accordance with aspects herein;

FIG. 4C illustrates another configuration of a knit heel element similar to FIG. 4A, in accordance with aspects herein;

FIG. 5 illustrates a cross-section taken at cut line 5-5 in FIG. 4 and schematically depicts a first example knit structure of a first knit zone of the knit heel element, in accordance with aspects herein;

FIG. 6 illustrates a cross-section taken at cut line 6-6 of FIG. 4 and schematically depicts the first example knit structure of FIG. 5 at a second knit zone of the knit heel element, in accordance with aspects herein;

FIG. 7 illustrates an example stitch notation for needle beds of a multi-bed knitting machine used to knit, in part, the example knit structure of FIGS. 5 and 6, in accordance with aspects herein;

FIG. 8 illustrates a block diagram of an example method of manufacturing at least the example knit structure of FIGS. 5 and 6, in accordance with aspects herein;

FIG. 9 illustrates a cross-section taken at cut line 9-9 in FIG. 4 and schematically depicts a second example knit structure of the first knit zone of the knit heel element, in accordance with aspects herein;

FIG. 10 illustrates a cross-section taken at cut line 10-10 in FIG. 4 and schematically depicts the second example knit structure of FIG. 9 of the second knit zone of the knit heel element, in accordance with aspects herein;

FIG. 11 illustrates a flow diagram of an example method of manufacturing at least the example knit structure of FIGS. 9 and 10, in accordance with aspects herein; and

FIG. 12 illustrates one example of an array of articles of footwear configured for different athletic activities with the articles of footwear including knit heel elements having different configurations, in accordance with aspects herein.

DETAILED DESCRIPTION

Traditional heel elements, which may be broadly defined as an element that gives structure, cushion, and/or support to a heel area of an upper for an article of footwear, typically are formed from rigid or semi-rigid materials such as leather, plastic, and the like. Moreover, traditional heel elements are typically attached to an outer-facing surface of an upper or otherwise inserted into an upper during a manufacturing process. In some instances, such rigid or semi-rigid materials can include sharp edges, which may cause discomfort for a wearer, including heel irritation, which is a common reason for returning or discarding footwear. In addition, in instances where a heel element includes cushioning, such as adjacent to a collar area of an upper, the cushioning element is generally secured to the heel element in an additional manufacturing step. Besides increasing the time, expense, and complexity associated with manufacturing articles of footwear, these additional manufacturing steps may increase the overall carbon footprint of footwear manufacturing. Moreover, the addition of reinforcement and/or cushioning elements may increase the bulk and weight of an article of footwear, among other undesirable attributes.

In aspects herein, an article of footwear having a knit element, including a knit heel element, methods of manufacturing knit elements and footwear, and in some aspects, arrays of articles of footwear that include knit heel elements that may have differing amounts of cushioning and/or rigidity dependent upon an intended use of the article of footwear, are provided. With respect to the knit heel element, aspects herein contemplate using different knit structures, different material processing, different types of yarns, and/or different amounts of a particular yarn to achieve varying amounts of cushioning and/or rigidity in different knit zones of a knit heel element. In aspects, the knit heel elements can be incorporated into an upper as the heel counter, e.g., the structure that imparts stiffness and cushioning in the heel area, without traditional heel counter components that are separately manufactured and incorporated into the upper in one or more additional manufacturing steps. Use of such knit heel elements is demonstrated to increase comfort, reduce manufacturing complexity, cost, and the number of steps, and provide a more seamless integration of components into knit footwear manufactured using automated knitting machines and post-processing techniques.

In example aspects, in a knit heel element, the amounts of cushioning and rigidity can be independently controlled such that a particular knit zone may have, for example, a high amount of cushioning and rigidity or hardness, a high amount of cushioning and a low amount of rigidity or hardness, a low amount of cushioning and a high amount of rigidity or hardness, or low amounts of both cushioning and rigidity or hardness. In some examples, the knit heel element may include transition areas between the different knit zones where the transition areas may include an intermediate rigidity or hardness and/or an intermediate amount of cushioning relative to the knit zones adjacent to the transition areas.

In some aspects, the cushioning and rigidity can be controlled to form a resilient, reversibly collapsible knit heel element that facilitates easy donning and doffing of the article of footwear. For example, a cushioning knit zone may be located adjacent to a collar area of the article of footwear, and a rigidity knit zone may be located below the cushioning knit zone adjacent to a sole structure of the article of footwear. The knit structure, the types of yarns used, and/or the quantity of yarns used may be adjusted such that when a wearer places his or her foot into the article of footwear, and the wearer's heel depresses and/or collapses the cushioning knit zone downward toward the rigidity knit zone, the wearer may easily slide her foot into the article of footwear. Once positioned within the article of footwear, the cushioning knit zone may quickly rebound upward and back to its extended shape. This feature may be especially useful for wearers with different hand and/or arm mobility or coordination abilities by enabling substantially hands-free donning of the article of footwear.

In a first example knit structure, the knit heel element may include a first knit layer forming an outer-facing surface of the knit heel element, a second knit layer forming an inner-facing surface of the knit heel element, and a third knit layer positioned between the first knit layer and the second knit layer, where the first, second, and third knit layers are integrally knitted with each other in a single knitting event (e.g., manufacturing process performed by a knitting machine). In a first knit zone of the knit heel element, which may correspond to a lower portion of the knit heel element positioned adjacent to a sole structure when the knit heel element is incorporated into an upper for an article of footwear, a thermoformed layer is at least partially positioned between the first knit layer and the third knit layer. The thermoformed layer may provide rigidity to the first knit zone, which may help to support an Achilles' tendon area of a wearer's foot. The first knit zone, in example aspects, may also include yarn ends of a cushioning yarn positioned between the second knit layer and the third knit layer. Locating the cushioning yarn(s) between the second knit layer and the third knit layer can position the cushioning yarn closer to a wearer's skin surface compared to positioning the cushioning yarn(s) between the first knit layer and the third knit layer. The cushioning yarn may provide some cushion between the wearer's skin surface and the more rigid thermoformed layer in the first knit zone.

The first knit structure may further include a second knit zone located at an upper portion of the knit heel element adjacent to a collar area of the upper. The second knit zone may comprise a number of yarn ends of the cushioning yarn positioned between the second knit layer and the third knit layer. The cushioning yarns may help to provide cushioning to the collar area of the upper which facilitates wearer comfort. In some example aspects, the second knit zone may also include yarn ends of a low-melting thermoplastic material positioned between the first knit layer and the third knit layer. The low-melting thermoplastic material may help to provide some resiliency and structure to the knit heel element in the second knit zone such that the knit heel element does not fold over in an undesired fashion.

To form the first knit structure, the first knit layer, the second knit layer, and the third knit layer are knitted on a dual-bed knitting machine during a single knitting event (e.g., a knitting operation performed by a knitting machine). In one example aspect, the first and third knit layers may be knit with a half-gauge structure on a first needle bed of the knitting machine. For example, the first knit layer may be knit on the first, third, fifth, and so on needles of the first needle bed, and the second knit layer may be knit on second, fourth, sixth, and so on needles of the first needle bed. The second knit layer may be knit on a second needle bed of the knitting machine. In this aspect, the first and third knit layers would have approximately half of the number of knit stitches per inch or centimeter than the second knit layer. In some aspects herein, using a high-melting thermoplastic yarn, e.g., such as a high-melting polyester yarn, and/or a high-melting recycled polyester yarn, to knit the first, second, and third knit layers is contemplated. Examples of polyesters that can be used in yarns that are included in the knit structures described herein include polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), among others. In example aspects, the high-melting thermoplastic yarns may be plated with a fusible yarn as defined below for added structural stability.

During the single knitting event, yarn ends comprising a low-melting thermoplastic material may be positioned between the first knit layer and the third knit layer. In some aspects, the yarn ends comprising the low-melting thermoplastic material may be interlooped with knit loops forming the first knit layer and the third knit layer. In one example, the yarn ends comprising the low-melting thermoplastic material may be intermittently floated between the first knit layer and the third knit layer and then tucked with knit loops forming the first knit layer and/or the third knit layer. During the single knitting event, yarn ends comprising a cushioning yarn may be positioned between the second knit layer and the third knit layer. In some aspects, the yarn ends comprising the cushioning yarn may be inlaid, e.g., via a combination feeder, between the second knit layer and the third knit layer, though aspects herein also contemplate interlooping the cushioning yarn with one or more knit loops forming the second knit layer and the third knit layer. Aspects herein contemplate zonally varying the number of yarn ends of the low-melting thermoplastic material and/or the cushioning yarn to achieve different functional purposes for different knit zones (e.g., the first knit zone and the second knit zone) of the knit heel element. Aspects herein also contemplate varying the types of yarns positioned between the first knit layer and the third knit layer and/or between the second knit layer and the third knit layer to achieve different functional purposes for the different knit zones. Any and all such aspects, and any variation thereof, are contemplated as being within the scope herein.

Methods of manufacturing a knit heel element may further include applying one or more of heat and pressure to a first knit zone of a knit heel element. The heat may be sufficient to melt the yarn ends comprising the low-melting thermoplastic material but not be high enough to melt, singe, burn, or otherwise destroy the structural integrity of the cushioning yarns and the high-melting thermoplastic yarns used to form the first, second, and third knit layers. The pressure may be applied to cause flowing of the melted thermoplastic material in one or more planes or directions. For example, the melted thermoplastic material may flow in an x, y plane such that it spreads between the first knit layer and the third knit layer. The melted thermoplastic material may also flow in a z-direction such as, for example, into and/or through the first knit layer such that, in some aspects, the melted thermoplastic material may be deposited onto the outer-facing surface of the knit heel element. The knit heel element is then cooled, which causes the melted thermoplastic material to re-solidify and form a thermoformed layer at least partially positioned between the first knit layer and the third knit layer. In some aspects, the thermoformed layer at least partially extends into and/or through the first knit layer.

In further example aspects, the amount of pressure applied to the first knit zone may be calibrated such that the thermoformed layer does not extend completely through the second knit layer or does not substantially extend through the second knit layer, thus maintaining the functional characteristics of the cushioning yarns that are positioned between the second knit layer and the third knit layer. As described, the thermoformed layer may impart structural rigidity to the first knit zone of the knit heel element. In example aspects, the heat and/or pressure are not applied to a second knit zone of the knit heel element, such that a thermoformed layer is not formed in the second knit zone and the functional characteristic of the second knit zone may be cushioning as opposed to rigidity. In some example aspects, a second heat and pressure application may occur to soften the thermoplastic material, including the thermoformed layer to shape the knit heel element into a desired three-dimensional shape. The knit heel element may then be incorporated into a heel area of an upper for an article of footwear.

In a second example knit structure, the knit heel element may comprise a first knit layer forming an outer-facing surface of the knit heel element, and a second knit layer forming an inner-facing surface of the knit heel element, where the first and second knit layers are integrally knitted with each other in a single knitting event. In a first knit zone of the knit heel element, which may correspond to a lower portion of the knit heel element positioned adjacent to a sole structure when the knit heel element is incorporated into an upper for an article of footwear, a thermoformed layer is at least partially positioned between the first knit layer and the second knit layer. In example aspects, the thermoformed layer may include one or more ends of a cushioning yarn. In additional example aspects, the thermoformed layer may also include one or more ends of a high-melting thermoplastic yarn, such as a high-melting PET yarn and/or a high-melting recycled PET yarn. The thermoformed layer may provide rigidity to the first knit zone, and, when used, the additional yarn ends of the cushioning yarn and/or the high-melting thermoplastic yarn may provide additional structural stability to the first knit zone by acting as a scaffold-type structure within the thermoformed layer.

The second knit structure may further include a second knit zone located at an upper portion of the knit heel element adjacent to a collar area of the upper. The second knit zone may comprise the first knit layer and the second knit layer. The second knit zone may further include yarn ends of the cushioning yarn positioned between the first knit layer and the second knit layer. The cushioning yarns may help to provide cushioning to the collar area of the upper, which facilitates wearer comfort. In some example aspects, the second knit zone may also include yarn ends of a low-melting thermoplastic material positioned between the first knit layer and the second knit layer. The low-melting thermoplastic material may help to provide some structure and resiliency to the knit heel element in the second knit zone such that the knit heel element does not inadvertently fold over.

To form the second knit structure, the first knit layer and the second knit layer can be knitted on a dual-bed knitting machine during a single knitting event. In one example aspect, the first knit layer may be knit on a first bed of the knitting machine, and the second knit layer may be knit on a second bed of the knitting machine. Aspects herein contemplate that one or more yarns from the first knit layer may be intermittently transferred to the second knit layer, and one or more yarns for the second knit layer may be intermittently transferred to the first knit layer. After being transferred, aspects herein contemplate that the yarn may be knit on the opposite bed for one or more knit loops before being transferred back to the origin bed. Aspects herein contemplate using a high-melting thermoplastic yarn and/or a high-melting recycled thermoplastic yarn such as a high-melting PET yarn, and/or a high-melting recycled PET yarn, to knit the first and second knit layers. In example aspects, the high-melting thermoplastic yarn may be plated with a fusible yarn for additional structural stability.

During the single knitting event, yarn ends comprising a low-melting thermoplastic material may be selectively positioned between the first knit layer and the second knit layer. Aspects herein contemplate that the low-melting thermoplastic yarn may comprise a low-melting PET yarn and/or a low-melting polyamide yarn. In some aspects, the low-melting thermoplastic yarn may be entirely formed from the low-melting PET and/or the low-melting polyamide (e.g., in connection with a knit zone that incorporates a cushioning yarn or yarn ends to help contain the expansion of the cushioning yarn or yarn ends in a desired fashion). In various examples, a yarn positioned between the first and second knit layers in at least a first knit zone of the knit heel element is a multi-component yarn having a high-melting thermoplastic material adjacent to a low-melting thermoplastic material. For instance, a yarn comprising a core/sheath configuration in which a core of a high-melting thermoplastic yarn is surrounded by a sheath of a low-melting thermoplastic material may be used in such a configuration. In other aspects, such a multi-component yarn having a high-melting thermoplastic material and low-melting thermoplastic material may have other configurations, such as a side-by-side configuration in which the low-melting thermoplastic material is positioned in a side-by-side configuration with the high-melting thermoplastic material, a trilobal configuration, and the like. In some aspects, the yarn ends comprising the low-melting thermoplastic material, e.g., those formed entirely from the thermoplastic material or that can comprise a core/sheath configuration that includes the thermoplastic material, may be interlooped with knit loops forming the first knit layer and the second knit layer. For example, the yarn ends comprising the low-melting thermoplastic material may be intermittently floated between the first knit layer and the second knit layer and then tucked with knit loops forming the first knit layer and the second knit layer. During the single knitting event, yarn ends comprising a cushioning yarn may be positioned between the first knit layer and the second knit layer. In some aspects, the yarn ends comprising the cushioning yarn may be inlaid between the first knit layer and the second knit layer, though aspects herein also contemplate interlooping the cushioning yarn with one or more knit loops forming the first knit layer and/or the second knit layer. In one example aspect, the tucks comprising the low-melting thermoplastic material may be used to modulate the amount of cushioning provided by the cushioning yarns. For example, a greater number of tucks per inch or centimeter may help to slightly compress the bulk of the cushioning yarns, leading to slightly less and/or more compact cushioning. Conversely, a fewer number of tucks per inch or centimeter may enable the cushioning yarns to fully expand leading to slightly more or less compact cushioning.

Aspects herein contemplate independently zonally varying the number of yarn ends of the low-melting thermoplastic material and/or the cushioning yarn to achieve different functional purposes for different knit zones (e.g., the first knit zone and the second knit zone) of the knit heel element. Aspects herein also contemplate varying the types of yarns positioned between the first knit layer and the second knit layer to achieve different functional purposes for the different knit zones. Any and all such aspects, and any variation thereof, are contemplated as being within the scope herein.

The method of manufacture may further include applying one or more of heat at a first temperature and pressure to a first knit zone of the knit heel element. In one aspect, this is done when the knit heel element is in a flat or planar configuration (so-called “flat-pressing”). The heat may be sufficient to melt the yarn ends comprising the low-melting thermoplastic material but not be high enough to melt, singe, burn, or otherwise destroy the structural integrity of the cushioning yarns, the high-melting thermoplastic yarns used to form the first and second knit layers, and/or the high-melting thermoplastic core of the yarn having the core/sheath configuration. The pressure may be applied to cause flow of the melted thermoplastic material in one or more planes. In example aspects, flat-pressing may be advantageous, as it generally facilitates a more even distribution and flow of the melted thermoplastic material as compare to, for example, three-dimensional pressing. The melted thermoplastic material may flow in an x, y plane such that it spreads between the first knit layer and the second knit layer. The melted thermoplastic material may also flow in a z-direction such as, for example, into, through, and/or substantially through the first knit layer. When the melted thermoplastic material flows through the first knit layer, it may form a deposit on the outer-facing surface of the knit heel element. The knit heel element is then cooled which causes the melted thermoplastic material to re-solidify and form a thermoformed layer at least partially positioned between the first knit layer and the second knit layer. In some aspects, the thermoformed layer at least partially extends into and/or through the first knit layer. As described, the thermoformed layer may impart structural rigidity or hardness to the first knit zone of the knit heel element. The amount of rigidity may be enhanced through use of the yarn ends comprising the cushioning yarn and the yarn ends comprising the core/sheath configuration. The cushioning yarns and the high-melting thermoplastic core of the core/sheath yarn may act as a scaffolding positioned within the thermoformed layer. In example aspects, the heat at the first temperature and the pressure are not applied to a second knit zone of the knit heel element such that a thermoformed layer is not formed in the second knit zone, and the functional characteristic of the second knit zone may be cushioning as opposed to rigidity.

In example aspects, the method may further include subsequently positioning the knit heel element on to a three-dimensional (3-D) form, e.g., such as a shoe last. Heat at a second temperature and pressure are applied to the knit heel element while positioned on the 3-D form, where the heat and the pressure are applied to an entirety of the knit heel element as opposed to a particular knit zone. In this aspect, the heat may be sufficient to soften the thermoformed layer in the first knit zone and to further soften the yarn ends comprising the thermoplastic material in the second knit zone. Softening the thermoplastic material allows the knit heel element to conform to the shape of the 3-D form. Once cooled, the knit heel element retains the desired shape. The method may further include incorporating the 3-D knit heel element into a heel area of an upper of an article of footwear.

In aspects, one or more thermoforming processes may be performed on a knit heel element that includes fusible materials to thermoform and/or fuse the materials in order to form structures of higher rigidity. In aspects, during one or more of the thermoforming processes that are performed, the knit heel element may be thermoformed into a three-dimensional shape, e.g., one that generally corresponds to a heel area of a footwear upper and/or to a shape of a heel-counter forming part of an upper or article of footwear for the purpose of providing stiffness, rigidity, and support, e.g., without separately manufactured heel-counter elements being incorporated.

Aspects herein further contemplate arrays of articles of footwear having knit heel elements with differing amounts of rigidity and cushioning dependent upon an intended use of the article of footwear. The knit heel elements may be formed using the first knit structure described above or the second knit structure described above. As an illustrative example, articles of footwear configured for the sport of basketball may generally cover the ankle bones of the wearer (e.g., as in high-tops). In this aspect, the knit heel element may have a need for a larger-sized cushioning zone (e.g., the second knit zone) as compared to, for example, an article of footwear configured for the sport of running in which the shoe collar generally rests below the ankle bones of the wearer (e.g., running). In another example, an article configured for the sport of global football (also known as soccer) may have an increased need for rigidity around the lower portion of the heel area to support the wearer's Achilles' tendon during various soccer maneuvers compared to an article of footwear configured for the sport of running in which greater flexibility may be needed in the heel area. The knit structures described herein may be easily customized by, for example, adding more yarn ends of cushioning yarns in specific zones to facilitate increased cushioning, increasing the size or surface area of a particular cushioning zone (e.g., the second knit zone) or rigidity zone (e.g., the first knit zone), adding more yarn ends of yarns comprising a thermoplastic material in specific zones to facilitate increased rigidity after processing, and the like. The frequency of tucks between the different knit layers may also be used to modulate the amount of cushioning imparted by the use of cushioning yarns.

As used herein, an article of footwear generally includes a sole structure secured to an upper. The article of footwear described herein may comprise a running shoe, a baseball shoe, a basketball shoe, a skateboarding shoe, a cycling shoe, an American football shoe, a tennis shoe, a global football shoe, a training shoe, a walking shoe, a hiking shoe, and the like. The concepts described herein may also be applied to other footwear types that are considered non-athletic such as dress shoes, loafers, sandals, casual shoes, and work boots. As used herein, the article of footwear may be divided into different general regions. A forefoot region generally includes portions of the article of footwear that correspond to the toes and joints connecting the metatarsals with the phalanges. A midfoot region generally includes portions of the article of footwear corresponding with an arch area and an instep area of the foot. A heel region generally corresponds with rear portions of the foot including the calcaneus bone. The article 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). The different regions and sides described above 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 term “knit element” as used herein may be broadly applied to any knit element applied to an upper that includes cushioning properties and/or rigidity properties as described herein. For example, the knit element may be applied to an insole area of an upper, a toe area of the upper, a heel area of the upper, and the like. The concepts described herein may relate to a knit heel element that is positioned in a heel area of the upper and generally extends from the sole structure to a collar area of the upper.

The term “outer-facing surface” as used herein refers to a surface of the knit element, an upper, or an article of footwear that faces the external environment. In some aspects, the outer-facing surface can mean the outermost-facing surface of the knit element, the upper, or the article of footwear. The term “inner-facing surface” as used herein refers to a surface of the knit element, the upper, or the article of footwear that faces a void for receiving the wearer's foot. In some aspects, the inner-facing surface may refer to the innermost-facing surface of the knit element, the upper, or the article of footwear.

The term “knit” as used herein, e.g., to describe 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 event. The course may comprise one or more stitch types known in the art of knitting, such as a knit stitch, a missed stitch, a tuck stitch, a transfer stitch, a rib stitch, and the like, as these terms are known in the art of knitting. The term “course-wise direction” refers to a direction that is parallel to the knit courses of the 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 “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). These multi-bed knit constructions may have two opposing layers of knit loops and/or tucks, e.g., one layer of loops formed on a first needle bed (e.g., a first knit layer), and a second layer of loops formed on a second needle bed (e.g., a second knit layer). In example aspects, the two layers may be joined by yarns that interloop with yarns in both the first knit layer and the second knit layer of the double knit construction. Common double knit constructions include double jersey, rib, interlock, cardigan, and other “double bed” knit structures initially formed on at least two needle beds, and other knit structures having two opposing faces or layers of knit loops or tucks, including full-gauge and less than full-gauge, e.g., half-gauge, variations of those structures. For instance, as described with respect to the first knit structure, aspects herein contemplate knitting two layers on a single needle bed (e.g., the first and third knit layers) using a half-gauge knitting technique.

The term “integrally knit,” as used herein, may refer to a knit textile having a yarn from one or more knit courses in a first area or zone being interlooped with one or more knit courses of another area or zone (e.g., the first knit zone and the second knit zone). The interlooping may be through a simple knit stitch, a tuck stitch, a held stitch, a float or miss stitch, or the like. In this way, areas or zones that are integrally knit together have a seamless transition such that they seamlessly extend from one another.

The term “yarn end” as used herein refers to the number of individual yarns. For example, five ends of Yarn A would mean five individual strands of Yarn A, where each strand may comprise a mono-filament yarn or a multi-filament yarn. When a dual-bed knitting machine is used, the yarn ends are generally supplied by one or more yarn feeders during a pass of the carriage. Thus, using the example above, five ends of Yarn A would be supplied by a feeder during a single pass of the carriage in a first direction. Alternatively, different ends of the same yarn (e.g., Yarn A) may be supplied by separate feeders during a single pass of the carriage in a first direction.

Forming the knit element using a knit construction may provide 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, and/or any combination thereof. These characteristics may be accomplished by selecting a particular knit structure, by varying the 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, or a similar material, and/or by selecting yarns of a particular size (e.g., denier) or tenacity (e.g., in grams per denier, “g/D”) and/or through use of a 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 knit elements may have different properties as described herein.

Yarns in accordance with aspects described herein can include mono-filament yarns and/or multi-filament yarns. In aspects, these can be formed from synthetic materials. In some aspects, the yarns may be generally described or designated as high-melting yarns or low-melting yarns. High-melting yarns may be used to knit, for example, the first, second, and third knit layers in the first knit structure, and the first and second layers in the second knit structure. Herein, the term “high-melting” generally refers to yarns at least partially formed of material that melts or softens at a particular elevated temperature, e.g., a temperature that is between about 175-200 degrees Celsius, or higher. In one example, high-melting thermoplastic yarns used in aspects herein may have a melting temperature of at least about 175 degrees Celsius. High-melting thermoplastic yarns can include high-melting PET yarns, high-melting recycled PET yarns, cushioning yarns, core/sheath yarns in which the core comprises a high-melting material (e.g., a high-melting PET core) and the sheath comprises a low-melting material, elastane yarns, and other high-melting synthetic, thermoplastic yarns. Low-melting yarns can include low-melting thermoplastic yarns. Herein, the term “low-melting” generally refers to yarns at least partially formed of material that melts or softens at a temperature that is lower than high-melting yarns, e.g., a temperature that is between about 60-170 degrees Celsius, or less. For example, low-melting yarns can partially or entirely be formed from materials that melt or soften at about 50 degrees Celsius to about 70 degrees Celsius; from about 55 degrees Celsius to about 65 degrees Celsius; or at about 60 degrees Celsius, in aspects. In aspects herein, low-melting yarns can be selected so that their low-melting material melts or softens at a temperature that is at least about 10-150 degrees Celsius less than that of the associated high-melting yarn(s) that are also incorporated into a knit element. In other words, low-melting yarns and high-melting yarns in a knit element can be selected so that a particular differential in melting/softening temperature is present. Low-melting thermoplastic yarns can include a synthetic polymeric material formed from a polymer that melts at relatively lower temperatures, e.g., less than 160 degrees Celsius, in particular aspects. In example aspects, low-melting yarns can be entirely formed from a low-melting thermoplastic material such as low-melting PET or low-melting polyamide. The term “fusible yarn” may be used herein to describe these types of yarns.

In some example aspects, the yarns used in portions of the knit structures described herein can be formed of materials that melt at different temperatures to impart selective characteristics in those portions of the knit structures. For example, areas of a knit element, e.g., that are in a heel area and/or that form part of a heel-counter, can contain yarns that include, partially or entirely, a material that melts at a certain temperature, e.g., a temperature that is between about 175-200 degrees Celsius. These yarns are considered the high-melt yarns. Other areas of a knit element, e.g., that are in a heel area and/or that form another part of a heel-counter, can contain yarns that include, partially or entirely, a material that melts at a certain temperature, e.g., a temperature that is between about 50-160 degrees Celsius. The particular yarn (e.g., single or multi-component), material (e.g., fusible or non-fusible and melting or softening temperature), and location of the yarn in a knit element can be selected to allow for fusing of yarns in desired areas, at desired temperatures, and to produce desired thermoformed structures, as described herein. These selectively positioned and thermoformed structures can impart stiffness, e.g., defining a heel counter area.

In aspects herein, a knit element, e.g., forming part of an upper for an article of footwear, e.g., a heel area or heel counter in particular, can in aspects include multiple types of fusible yarns. For example, in some aspects, a twisted yarn that includes high-melting filament polyester that is twisted with a low-melting fusible polyester can be used in a knit element. The twisted yarn can be used in a zone of the knit element where high rigidity and/or stiffness is desired (e.g., can be used for stiffness in place of a traditional heel-counter insert or attachment that is typically formed from foam, plastic, polymer, leather, or another stiff material, or in place an injection molded polymer, among other things). The combination of the fused low-melting fusible polyester and the high-melting filament polyester can be used to impart extra reinforcement in the associated area. In additional aspects, a fusible yarn can be used in a cushioning zone of a knit element, e.g., in a heel area or heel-counter, to generally help keep a cushioning yarn in place during a knitting process. In such aspects, the fusible yarn can be formed of an entirely low-melting polymer, e.g., low-melting fusible polyester. In such instances, once heat-processed, the low-melting fusible polymer melts, re-flows, and then occupies spaces between the cushioning yarn where it re-solidifies to help contain the expansion of the cushioning yarn, without substantially limiting or constricting the cushioning yarn's padding or cushioning properties.

Low-melting yarns can include yarns having a high-melting thermoplastic core formed from, for example, high-melting PET, surrounded by a sheath of low-melting thermoplastic material such as thermoplastic polyurethane (TPU), thermoplastic polyethylene (TPE), and/or other synthetic polymeric materials having a lower melting point relative to high-melting materials. In an aspect, a low-melting sheath may be melted upon application of a temperature at or below 170 degrees Celsius, such as around 120 degrees Celsius, while the high-melting core remains intact. In example aspects, the melting temperature of the thermoplastic material may be sufficiently different from the melting temperature of the high-melting yarns that the thermoplastic material of the low-melting yarns may be essentially completely melted without melting or adversely affecting (e.g., burning, charring, or singeing) the characteristics of the high-melting yarns.

The term “thermoformed,” as used herein, refers to a structure that is formed by applying heat and/or pressure to a thermoplastic material such that it melts and then is re-solidified and hardened upon cooling. Thus, in aspects, a thermoformed layer may comprise the same polymeric material as the thermoplastic material that forms part of the low-melting yarns described herein and incorporated into knit elements.

The term “cushioning yarn,” as used herein, can in aspects describe yarns with a full diameter (e.g., when not restricted or compressed) of about 1/16 inch (or about 1.58 millimeters) or larger, for example. However, other cushioning yarns may have other diameters (e.g., ⅛ inch or about 3.18 millimeters, ¼ inch or about 6.35 millimeters, or even larger). Two non-limiting examples of cushioning yarns are a 5500 denier version and a 3500 denier version of multi-filament polyester yarn that has been texturized to loft. These types of yarns are generally compressible, which contributes to their cushioning features. Particularly, these yarns may have a first diameter in an uncompressed state and a second, smaller diameter, in a compressed state. Particular examples are marketed as “LILY” yarns and are sold by Sawada Hong Kong Co. Ltd., though other yarns from other manufacturers may also be cushioning yarns. Another example of a cushioning yarn may be a foamable or expandable yarn and/or a scrap leather yarn (SLY yarn).

Numerous aspects herein may refer to the hardness or rigidity of a knit zone associated with a knit element. In aspects, such hardness can be measured using ASTM D2240 type A and type D scales.

Numerous aspects herein may refer to resiliency or stiffness of a knit zone associated with a knit element. In aspects, such resiliency or stiffness can be measured using the SATRA TM83 test method.

Unless indicated otherwise, all measurements provided herein are taken when the knit element, the upper, and/or the article of footwear is at standard ambient temperature and pressure (298.15 K and 100 kPa) and is in a resting (non-tensioned) state. As used herein, the term “about” means within ±10% of an indicated value.

FIGS. 1-3 schematically depict a medial view, a lateral view, and a rear view, respectively, of an example article of footwear 100 having an upper 110, a sole structure 112 secured to the upper 110, and a knit heel element 114 located at a heel area of the upper 110. With respect to the knit heel element 114, the knit heel element 114 includes an outer-facing surface 116 and an opposite inner-facing surface 118. The article of footwear 100 is shown in the form of an athletic shoe, but other types of shoes (e.g., sandals, leisure shoes, boots, and the like) are contemplated herein. The article of footwear 100 includes a forefoot region 120 having a toe area 121, a midfoot region 122, and a heel region 124 having a heel area 125, a medial side 126, and a lateral side 128. The article of footwear 100 includes a collar 130, which, in example aspects, may comprise the upper edge of the knit heel element 114. The collar 130 includes an opening 132 for receiving a wearer's foot. The article of footwear 100 further includes a throat area 134, and an optional tongue 136. Although not shown, aspects herein contemplate that the article of footwear 100 may include additional elements layered on top of the upper 110 including, for example, leather materials, synthetic leather materials, knitted or woven textiles, polymer skins, and the like.

With respect to the knit heel element 114, in example aspects, the knit heel element 114 extends around the heel area 125 of the article of footwear and further extends forward (e.g., toward the toe area 121) on the medial side 126 and the lateral side 128 in the heel region 124 of the article of footwear 100. In example aspects, the knit heel element 114 includes a first knit zone 138, which may also be known as a first knit composite zone, that extends from an intersection of the knit heel element 114 with the sole structure 112 (e.g., biteline 106) upward (e.g., toward the collar 130) a predetermined distance. As will be further described, the first knit zone 138 may comprise a first level of hardness or rigidity or stiffness that causes the first knit zone 138 to function as a heel counter that supports the wearer's heel in general and the lower part of the wearer's Achilles' tendon. The knit heel element 114 also includes a second knit zone 140, which also may be known as a second knit composite zone, that seamlessly or integrally extends from the first knit zone 138 toward the collar 130. The second knit zone 140 has a second level of hardness or rigidity or stiffness that is less than the first knit zone 138. To describe this differently, a concentration per unit volume, per unit of surface area, and/or by weight of thermoplastic material in the second knit zone 140 or the second knit composite zone may be less than a concentration per unit volume, per unit of surface area, and/or by weight of the thermoplastic material in the first knit zone 138 or first knit composite zone. In example aspects, the second knit zone 140 exhibits cushioning features that facilitate wearer comfort, especially around or near the sensitive lateral and medial malleoli of the wearer's feet.

In one non-limiting aspect, the demarcation between the first knit zone 138 and the second knit zone 140 may comprise an abrupt transition, as indicated by a first boundary line 142. In this aspect, the area immediately below the first boundary line 142 may exhibit rigidity characteristics, and the area immediately above the first boundary line 142 may exhibit cushioning characteristics, or greater cushioning characteristics than below the first boundary line 142. In other example aspects, the transition may be more gradual, such that you have a gradually decreasing level of rigidity transitioning to a gradually increasing level of cushioning as the first knit zone 138 transitions to the second knit zone 140.

In example aspects, the knit heel element 114 may also include an optional collar (the collar 130) that seamlessly or integrally extends from the second knit zone 140. In example aspects, the collar 130 may have a rigidity or hardness less than the second knit zone 140 and the first knit zone 138. In aspects, the collar 130 may include elastic yarns (e.g., elastane yarns) that facilitate the stretch needed when a wearer is inserting their foot into the opening 132, and the subsequent recovery when the foot is fully inserted into the article of footwear 100. In example aspects, the collar 130 does not include the thermoplastic polymer material of the low-melting thermoplastic yarns of the first and second knit zones 138 and 140 and, further, may not include any thermoplastic polymer materials. In some examples, the collar 130 includes only elastic yarns. The demarcation between the second knit zone 140 and the collar 130 may comprise an abrupt transition, as indicated by the second boundary line 144. In this aspect, the area immediately below the second boundary line 144 may exhibit cushioning characteristics, and the area immediately above the second boundary line 144 may exhibit stretch and recovery properties. In other example aspects, the transition may be more gradual, such that you have a gradually decreasing level of cushioning transitioning to a gradually increasing level of stretch and recovery as the second knit zone 140 transitions to the collar 130. In yet other example aspects, a separate collar element may be added to the knit heel element 114 in a subsequent manufacturing step (e.g., a post-knitting step). In this aspect, the second knit zone 140 may terminate at an upper edge, and the separate collar element may be affixed to the upper edge of the second knit zone 140. The shape configuration depicted for the knit heel element 114 including the configuration of the first boundary line 142 and the second boundary line 144 are illustrative examples, and other configurations are contemplated herein.

FIG. 4A depicts a configuration of a knit heel element 114A in isolation, or rather, removed from the article of footwear 100 and positioned in a flat (planar) configuration with the outer-facing surface 116 of the knit heel element 114A visible. The knit heel element 114A has a knit construction as indicated by knit courses 402 extending in a course-wise direction and knit wales 404 extending in a wale-wise direction, as shown in the enlarged views. Although the enlarged views shows the course-wise direction as generally being a lateral direction such that knit courses 402 generally extend from a lateral side to a medial side, it should be understood that the knit heel element 114A may be knit in another manner so that the knit courses 402 extend in different directions. For example, knit courses 402 may extend in a top-to-bottom direction along the height of the knit heel element 114A or may extend radially from an outer perimeter to a common portion, such as the opening 132 (shown in FIGS. 1-2).

As depicted, the knit heel element 114A includes a lower edge 410, an upper edge 412, a first side edge 414 joining a first end of the lower edge 410 to a first end of the upper edge 412, and a second side edge 416 joining an opposite second end of the lower edge 410 to an opposite second end of the upper edge 412. In example aspects, the lower edge 410 would be joined to the sole structure 112 of the article of footwear 100, the first side edge 414 would be joined to the upper 110 on the medial side 126 of the article of footwear 100, and the second side edge 416 would be joined to the upper 110 on the lateral side 128 of the article of footwear 100. In example aspects, the upper edge 412 of the knit heel element 114A may comprise a free edge (e.g., an edge not joined to another element or structure) or it may be affixed to a separate element (e.g., a collar element). The first knit zone 138 extends from the lower edge 410 to the first boundary line 142. As such, the first boundary line 142 corresponds to a first knit zone upper edge 146. The second knit zone 140 extends from the first boundary line 142 (or the first knit zone upper edge 146) to the collar 130 and/or to the upper edge 412 if the collar 130 is not present.

The knit heel element 114A depicted in FIG. 4A is depicted as a separate heel element that may be joined to other pieces to form the upper 110. However, it is contemplated that aspects herein include the knit heel element 114A being integrally knitted with structures forming other portions, (such as a midfoot portion, a forefoot portion, and/or an underfoot portion) of the upper 110, e.g., in a common knitting operation performed by a knitting machine.

The knit heel element 114A in FIG. 4A is generally symmetrical with respect to a hypothetical vertical midline 418 (which would generally extend from the collar 130 to the biteline 106), although aspects herein contemplate that the knit heel element 114A may not be symmetrical with respect to the vertical midline 418. As described, the function of the first knit zone 138 is generally to provide support to the Achilles' tendon area of a wearer's foot, which generally aligns with the vertical midline 418. As such, there may not be a need for as much hardness or rigidity as the knit heel element 114A extends toward the first side edge 414 and the second side edge 416. Conversely, as described, the function of the second knit zone 140 is generally to provide cushioning adjacent the collar 130 and along the sides of a wearer's heel. These functional difference requirements are reflected in the placement and configuration of the first knit zone upper edge 146.

In one example, a first distance 148 between the first knit zone upper edge 146 and a second knit zone upper edge 147 (which aligns with second boundary line 144) can be greater at the first side edge 414 and the second side edge 416 compared to a second distance 150 between the first knit zone upper edge 146 and the second knit zone upper edge 147 at the vertical midline 418, e.g., at and/or adjacent to a central area 153 as shown in FIG. 4A (or generally lesser as shown in FIG. 4C). Having a greater distance (e.g., the first distance 148) between the first knit zone upper edge 146 and the second knit zone upper edge 147 at the first side edge 414 and the second side edge 416 corresponds to an increased surface area of the second knit zone 140 with its cushioning properties. Having a smaller distance (e.g., the second distance 150) between the first knit zone upper edge 146 and the second knit zone upper edge 147 at the vertical midline 418 corresponds to an increased surface area of the first knit zone 138 with its hardness or rigidity properties. This positioning and relative area of the zones can differ based on desired support in the heel region and/or different desired cushioning in the heel region, or can be based on the intended use of the associated footwear (e.g., basketball, global football, or other activities, and so on).

In some aspects, it can be desirable to have a greater stiffness and/or rigidity at and/or adjacent to the central area 153 of the knit heel element 114A shown in FIG. 4A, e.g., to allow for greater overall support and structural rigidity. To accomplish this, the second distance 150 can be reduced such that there is an increased area of the first knit zone 138 with its hardness and/or rigidity properties present at and/or adjacent to the central area 153. In some aspects, this can additionally or alternatively be accomplished by including fusible yarns in the second knit zone 140 having cushioning properties.

In some aspects, the area of the first knit zone 138, e.g., having a more rigid structure, can be greater than the area covered by the second knit zone 140, e.g., having a more cushioned structure, e.g., in the knit heel element 114A shown in FIG. 4A. This can help increase the rigidity, stiffness, and support in a knit heel element as described herein, in particular when it is used as a heel-counter, e.g., in place of a traditional heel-counter insert or attachment. To provide an example, FIG. 4B shows a knit heel element 114B having a configuration somewhat similar to FIG. 4A, but with the relative areas of the first knit zone 138 and the second knit zone 140 adjusted such that the first knit zone 138 covers a greater surface area of the knit heel element 114B than the second knit zone 140 as compared to FIG. 4A. This causes the geometry of the first knit zone upper edge 146 and the second knit zone upper edge 147 to shift and by association the relative positions of the first boundary line 142 and the second boundary line 144 to change, as shown in FIG. 4B in comparison to FIG. 4A. With the knit heel element 114B, as the first knit zone 138 and the second knit zone 140 transition outward in a direction perpendicular to the vertical midline 418, the knit zones 138, 140 transition upward towards the collar 130 in a shorter distance compared to the knit heel element 114A shown in FIG. 4A. This shorter distance of the first knit zone 138 converging with the collar 130 on opposite sides of the central area 153 reduces the lateral displacement of the more cushioned zone 140. From that point on, the first knit zone 138 and the collar 130 extend without the second knit zone 140. This can increase the stiffness around the lateral heel areas of the knit heel element 114. This has been demonstrated to enhance support in these areas and reduce sagging, folding, and bunching around the lateral portions of the knit heel element 114B, which is undesirable in certain applications.

In some aspects of the knit heel element 114, the first knit zone 138, e.g., having a more rigid structure, can extend generally through the area of the second knit zone 140, e.g., having a more cushioned structure. For example, as shown in FIG. 4C, the knit heel element 114C is configured such that the first knit zone 138 extends generally through the second knit zone 140 generally along the vertical midline 418. This configuration can impart additional reinforcement and support along and/or adjacent to the heel line 155 of the knit heel element 114C, and segment the second knit zone 140, e.g., having a more cushioned structure, onto opposite lateral sides of the vertical midline 418.

Looking again at FIG. 4A, in some aspects, the first knit zone upper edge 146 may be shaped such that the first knit zone upper edge 146 forms a valley 157 at the vertical midline 418, where the first knit zone 138 includes protruding portions 159 on each side of the valley 157 that each extend further upwards relative to the valley 157. In this way, a third distance 151 between the first knit zone upper edge 146 and the second knit zone upper edge 147 at these protruding portions 159 on lateral and medial sides of the vertical midline 418 may be smaller than the second distance 150 between the first knit zone upper edge 146 and the second knit zone upper edge 147 at the vertical midline 418. These protruding portions 159 may be intended to be positioned posterior to a wearer's lateral and medial malleoli when the upper 110 with the knit heel element 114 is worn. Having this smaller distance (e.g., the third distance 151) between the first knit zone upper edge 146 and the second knit zone upper edge 147 at the protruding portions 159 corresponds to an increased surface area of the first knit zone 138 with its hardness or rigidity properties to provide posterior support to the wearer's lateral and medial malleoli. Additionally, in some aspects, the second knit zone upper edge 147 (which aligns with second boundary line 144) may slope downward as the second knit zone upper edge 147 extends away from the vertical midline 418 (or upward for greater stiffness in these areas as shown in FIGS. 4B and 4C). In this way, the second knit zone upper edge 147 may be extending downward where the first knit zone upper edge 146 is extending upwards, further decreasing the third distance 151 between the first knit zone upper edge 146 and the second knit zone upper edge 147 than the second distance 150 between the first knit zone upper edge 146 and the second knit zone upper edge 147.

FIG. 5 schematically depicts a cross-section of the first example knit structure 500 taken at cut line 5-5 of FIG. 4A which corresponds to the first knit zone 138. As described above, the knit heel element 114 may be knit using at least the first knit structure 500 or the second example knit structure described above. Aspects associated with the second example knit structure will be described with respect to FIGS. 9-11.

With respect to FIG. 5, the first knit structure 500 at the first knit zone 138 includes a first knit layer 510 that forms the outer-facing surface 116 of the knit heel element 114, a second knit layer 512 that forms the inner-facing surface 118 of the knit heel element 114, and a third knit layer 514 positioned between the first knit layer 510 and the second knit layer 512. In example aspects, each of the first knit layer 510, the second knit layer 512, and the third knit layer 514 may be knit using a high-melting yarn such as a high-melting PET yarn and/or a high-melting recycled PET yarn although other high-melting yarn types are contemplated herein. In example aspects, the high-melting yarn may be plated with a fusible yarn to impart stability and/or structure to the first, second, and/or third knit layers 510, 512, and 514.

In example aspects, there may be yarn transfers between the first knit layer 510 and the second knit layer 512, as indicated by dashed transfer line 513. For example, a yarn from the first knit layer 510 may be intermittently transferred to the second knit layer 512 where it may be knit in one or more knit loops of the second knit layer 512 before being transferred back to the first knit layer 510. In addition, a yarn from the second knit layer 512 may be intermittently transferred to the first knit layer 510 where it may be knit in one or more knit loops of the first knit layer 510 before being transferred back to the second knit layer 512. There may also be yarn transfers between the third knit layer 514 and the second knit layer 512, as indicated by dot-dash transfer line 515. For example, a yarn from the third knit layer 514 may be intermittently transferred to the second knit layer 512 where it may be knit in one or more knit loops of the second knit layer 512 before being transferred back to the third knit layer 514. In addition, a yarn from the second knit layer 512 may be intermittently transferred to the third knit layer 514 where it may be knit in one or more knit loops of the third knit layer 514 before being transferred back to the second knit layer 512.

As explained further below with respect to FIG. 7, the first and third knit layers 510 and 514 may be knitted on one bed of a knitting machine, each using a half-gauge technique in which needles on that needle bed alternate between being used for the first knit layer 510 and the third knit layer 514. As such, the yarn transfers 513 between the second knit layer 512 and the first knit layer 510 are done on different needle positions than yarn transfers 515 between the second knit layer 512 and the third knit layer 514.

In the first knit zone 138, a thermoformed layer 516 is at least partially positioned between the first knit layer 510 and the third knit layer 514. The thermoformed layer 516 is formed from a thermoplastic material such as, for example, TPU, TPE, PET, and/or polyamide. In example aspects, the thermoformed layer 516 may at least partially penetrate the first knit layer 510 and/or the third knit layer 514. In example aspects, the thermoformed layer 516 may fully penetrate the first knit layer 510 such that the thermoplastic material of the thermoformed layer 516 is deposited on the outer-facing surface 116 of the knit heel element 114, as indicated by reference numeral 518. The deposit may be continuous, such that a film on the outer-facing surface 116 is formed, or may be discontinuous in example aspects. While in some aspects, the thermoformed layer 516 may fully penetrate the third knit layer 514, it may not fully penetrate the third knit layer 514 in other aspects. In example aspects, the thermoformed layer 516 may not contact or substantially not contact the second knit layer 512. As described below, cushioning yarns 520 may be positioned between the second knit layer 512 and the third knit layer 514. By not having the thermoformed layer 516 extend through the second knit layer and/or otherwise contact the cushioning yarns 520 (in aspects including cushioning yarns 520), the cushioning yarns 520 may not be entrapped by the thermoformed layer 516, which may facilitate their cushioning properties.

In the first knit zone 138, the first knit structure 500 may further include yarn ends of a cushioning yarn 520 positioned between the second knit layer 512 and the third knit layer 514. Although only one yarn end of the cushioning yarn 520 is depicted, aspects herein contemplate that there may be multiple yarn ends of the cushioning yarn 520 between the second knit layer 512 and the third knit layer 514 in the first knit zone 138 dependent upon a desired level of cushioning. In other aspects, there may be zero yarn ends of the cushioning yarn 520 between the second knit layer 512 and the third knit layer 514. In example aspects, and as shown, the cushioning yarn 520 may be inlaid between the second knit layer 512 and the third knit layer 514. When the cushioning yarn 520 is inlaid, it does not form intermeshed loops with other yarns. For smaller diameter cushioning yarns, the cushioning yarn 520 may be knit into one or more of the second knit layer 512 and the third knit layer 514 using, for example, intermittent tucks and floats.

The cushioning yarn 520 is a compressible yarn such that the diameter may be compressed, or decreased when a compression force is applies. In one example aspect, the yarn transfers 513 between the second knit layer 512 and the first knit layer 510 and yarn transfers 515 between the second knit layer 512 and the third knit layer 514 may each apply tension to the cushioning yarn 520 between these knit layers 510, 512, and 514, which decrease the diameter and loft of the cushioning yarn 520. In this way, the greater density of yarn transfers 513 and/or 515 results in reduced cushioning compared to lower density of yarn transfers 513 and 515. In another way, compression from a greater density of yarn transfers 513 and 515 may compress the cushioning yarns 520 to generate a denser cushion structure.

The location of the thermoformed layer 516 between the first knit layer 510 and the third knit layer 514 means that the thermoformed layer 516 is positioned closer to the outer-facing surface 116 of the knit heel element 114 compared to the location of the cushioning yarns 520 between the second knit layer 512 and the third knit layer 514. This may have functional advantages, as the hardness and/or rigidity associated with the thermoformed layer 516 may be uncomfortable to a wearer. Thus, positioning the cushioning yarns 520 closer to the skin surface of a wearer's foot may cushion the effects of the thermoformed layer 516 on the wearer's skin and make the knit heel element 114 more comfortable to wear. Stated differently, in the first knit structure 500, the cushioning yarns 520 create a separation between the thermoformed layer 516 and the wearer's skin, which contributes to wearing comfort. Additionally, positioning the thermoformed layer 516 closer to the outer-facing surface 116 may have the effect of providing waterproof or water-resistant properties and abrasion resistance to the knit heel element 114.

FIG. 6 schematically depicts the first knit structure 500 at the second knit zone 140 of the knit heel element 114. The first knit structure 500 at the second knit zone 140 includes the first knit layer 510, the second knit layer 512, the third knit layer 514, the cushioning yarn 520, and the yarn transfers 513 and 515 between the first, second, and third knit layers 510, 512, and 514. The discussion of these elements provided for FIG. 5 also applies to FIG. 6. Instead of the thermoformed layer 516 located at least partially between the first knit layer 510 and the third knit layer 514 in the first knit zone 138, a number of yarn ends of a low-melting thermoplastic material 610 are located between the first knit layer 510 and the third knit layer 514. In one example aspect, the yarn ends of the low-melting thermoplastic material 610 may comprise fusible yarns that comprise, for example, low-melting PET and/or low-melting polyamide. In another example aspect, the yarn ends of the low-melting thermoplastic material 610 may comprise a core/sheath yarn where the sheath is formed from a low-melting thermoplastic material such as, for example, TPU or TPE, and the core comprises a high-melting yarn such as high-melting PET. In yet another example aspect, the yarn ends of the low-melting thermoplastic material 610 may comprise a combination of fusible yarns and the core/sheath yarns.

Aspects herein contemplate that the yarn ends of the low-melting thermoplastic material 610 may be interlooped with one or more yarns in the first knit layer 510 and the third knit layer 514, as shown by the zig-zag configuration in FIG. 6. The interlooped nature of yarn ends of the low-melting thermoplastic material 610 in the second knit zone 140 is in contrast to the thermoformed layer 516 comprising the low-melting thermoplastic material in the first knit zone 138. In this aspect of the second knit zone 140, the yarn ends of the low-melting thermoplastic material 610 may be intermittently floated and tucked into the first knit layer 510 and the third knit layer 514. In example aspects, the amount of tucks per inch or centimeter may be increased to increase the compression of the cushioning yarns 520 to create a denser cushion. Alternatively, the amount of tucks per inch or centimeter may be decreased to decrease the compression of the cushioning yarns 520 to create a less dense, or loftier, cushion.

FIG. 7 depicts a schematic of a possible knitting machine configuration that is used to form the first knit layer 510, the second knit layer 512, and the third knit layer 514. For example, the first and third knit layers 510 and 514 may be knitted on one bed of a knitting machine, each layer knit using a half-gauge technique. For example, yarn(s) used to form the first knit layer 510 may be knit on needles 1, 3, 5, and so on, and yarn(s) used to form the third knit layer 514 may be knit on needles 2, 4, 6, and so on. Thus, both the first knit layer 510 and the third knit layer 514 are knit with each pass of the knitting carriage. The yarns used to form the first knit layer 510 and the third knit layer 514 may not be interlooped with one another but may overlap each other, such that the first knit layer 510 may be generally positioned on an outer-facing side of the third knit layer 514. The second knit layer 512 may be knit on the opposing bed of the knitting machine using a full-gauge technique. For example, yarns of the second knit layer 512 may be knit on all the needles (e.g., needles 1, 2, 3, 4, 5, and so on). The result of this technique (forming the first and third knit layers 510 and 514 with half-gauge and the second knit layer 512 with full-gauge) may be that the number of knit stitches per inch or centimeter for the first knit layer 510 and the third knit layer 514 may be approximately half of the number of knit stitches per inch or centimeter for the second knit layer 512.

FIG. 8 depicts a block diagram of an example method 800 of manufacturing a knit heel element, such as the knit heel element 114, e.g., using the first knit structure 500, in accordance with aspects herein. In block 810, a first knit layer, such as the first knit layer 510; a second knit layer, such as the second knit layer 512; and a third knit layer, such as the third knit layer 514, are knit on a knitting machine during a single knitting event. In example aspects, the knit heel element may be knit to shape such that additional trimming or cutting is not needed. In other example aspects, the knit heel element may be cut to shape during the manufacturing process. Further, in example aspects, the knit heel element is knit as an individual piece but it is also contemplated that the knit heel element may be integrally knit with the rest of the upper or at least other portions of the upper outside the heel region.

As described, the third knit layer is positioned between the first knit layer and the second knit layer. The first knit layer and the third knit layer may be knit on one needle bed using a half-gauge technique, while the second knit layer may be knit on the opposing bed using a full-gauge technique. The first, second, and third knit layers may be knit using, for example, a high-melting thermoplastic yarn such as a high-melting PET yarn, and/or a high-melting recycled PET yarn, both of which may be optionally plated with a fusible yarn.

In block 812, yarn ends comprising a low-melting thermoplastic material, such as the yarn ends of material 610, may be positioned between the first knit layer and the third knit layer. In example aspects, the yarn ends comprising the low-melting thermoplastic material may be interlooped with yarns in the first knit layer and the third knit layer using tucks and floats, for example. Aspects herein contemplate that the yarn ends comprising the low-melting thermoplastic material may be zonally positioned based on a desired end function. For example, in knit zones of the knit element for which a greater hardness or rigidity is desired, such as the first knit zone 138, a greater number of yarn ends of the thermoplastic material may be positioned between the first and third knit layers. In knit zones of the knit element for which a greater amount of cushioning is desired, such as the second knit zone 140, a fewer number of yarn ends comprising the thermoplastic material may be positioned between the first and third knit layers. In some example aspects, zero yarn ends of the thermoplastic material may be positioned between the first and third knit layers.

In block 814, yarn ends comprising a cushioning yarn such as the cushioning yarn 520 are positioned between the second knit layer and the third knit layer. The cushioning yarns may be inlaid, particularly where it has a relatively high diameter. Otherwise, they may be interlooped with yarns in the second knit layer and/or the third knit layer. Aspects herein contemplate that the yarn ends of the cushioning yarn may be zonally positioned based on a desired end function. For example, in knit zones of the knit heel element for which a high degree of cushion is desired, such as the second knit zone 140, a greater number of yarn ends of the cushioning yarn may be positioned between the second and third knit layers. In knit zones of the knit heel element for which a greater amount of hardness or rigidity is desired, such as the first knit zone 138, a fewer number of yarn ends comprising the cushioning yarn may be positioned between the second and third knit layers. In some example aspects, zero yarn ends of the cushioning yarn may be positioned between the second and third knit layers.

Aspects herein further contemplate that the amount of cushioning imparted by the cushioning yarns may be modulated by the transfers, such as the transfers 513 and 515, between the first, second, and third knit layers and/or by tucks of the low-melting thermoplastic yarn. For example, a greater number of transfers or tucks per inch or centimeter may compress the cushioning yarns, resulting in less cushion and/or a denser cushion. Conversely, a fewer number of transfers or tucks per inch or centimeter may result in greater cushion or less dense cushion.

Blocks 810, 812, and 814 are described separately above to discuss particular details of each aspect of the knit structure. However, it should be understood that these steps can occur simultaneously, such that the high-melting yarns for the first knit layer, the second knit layer, the third knit layer, yarn(s) with the low-melting thermoplastic material, and the cushioning yarn may be knit across needle beds within a single pass of a carriage using multiple feeders.

In block 816, one or more of heat and pressure are applied to a first knit zone, such as the first knit zone 138 of the knit heel element. The heat may be at a temperature sufficient to melt the low-melting thermoplastic material of the yarns positioned between the first knit layer and the third knit layer but not high enough to damage the high-melting yarns including the yarns used to form the first, second, and third knit layers, the cushioning yarn, and/or the core of the yarn with low-melting thermoplastic material in aspects having a core/sheath structure. The applied pressure causes the melted thermoplastic material to flow between the first and third knit layers. When cooled, a thermoformed layer, such as the thermoformed layer 516, is formed between the first and third knit layers. In some aspects, the pressure may be sufficient to cause the thermoplastic material to penetrate into or through the first knit layer and/or the third knit layer. As well, the pressure may be modulated such that the melted thermoplastic material does not contact the second knit layer and/or the cushioning yarns positioned between the second and third knit layers, thus helping to maintain the loft and/or cushion imparted by the cushioning yarns in the areas they are located. In example aspects, the heat and pressure are not applied to a second knit zone, such as the second knit zone 140, such that a thermoformed layer is not formed in the second knit zone.

Aspects herein contemplate that after the knit heel element is cooled and the thermoformed layer is formed, an additional heat and pressure application may occur to an entirety of the knit heel element (e.g., to the first and second knit zones). In this application, the heat may be sufficient to soften but not melt the thermoplastic material of the yarn ends in the second knit zone, and the thermoformed layer. This application may occur after the knit heel element is positioned on a 3-D form, such as a shoe last. In addition, pressure may be applied to the knit heel element such that it conforms to the 3-D form. The pressure, in some aspects, may be through the application of sand to the 3-D form. For example, the knit heel element may be positioned on a 3-D form and placed in a vacuum chamber with sand running through the chamber while the chamber and/or 3-D form is heated. The use of sand may ensure a more even distribution of pressure to the knit heel element such that an entirety of the knit heel element closely conforms to the three-dimensional shape of the 3-D form.

In block 818, the knit heel element is incorporated into a heel area and/or a heel region, such as the heel region 124 and the heel area 125 of an article of footwear such as the article of footwear 100. The knit heel element is positioned such that the first knit zone is located adjacent to the sole structure and the second knit zone is located adjacent to the collar of the article of footwear. In this fashion, the knit heel element can, in some aspects, form and take the traditional place of a footwear heel counter that is otherwise separately formed/incorporated into or onto the heel area in connection with additional manufacturing steps.

FIG. 9 schematically depicts a cross-section of the second example knit structure 900 taken at cut line 9-9 of FIG. 4A, which corresponds to the first knit zone 138. The second knit structure 900 at the first knit zone 138 includes a first knit layer 910 that forms the outer-facing surface 116 of the knit heel element 114, and a second knit layer 912 that forms the inner-facing surface 118 of the knit heel element 114. In example aspects, each of the first knit layer 910 and the second knit layer 912 may be knit using a high-melting yarn such as a high-melting PET yarn and/or a high-melting recycled PET yarn, although other high-melting yarn types are contemplated herein. In example aspects, the high-melting yarn may be plated with a fusible yarn to impart additional structure and stability to the first and second knit layers 910 and 912. In some aspects, the high-melting yarn is plated with the fusible yarn in the first knit layer 910 while the second knit layer 912 that forms the inner skin-facing side comprises a textured yarn. Examples of textured yarns include but are not limited to chenille yarn, peached yarn, and the like. Thus, as a result, when the knit heel counter is processed (e.g., using heat and/or pressure) after knitting, the inner skin-facing side has a softer hand thus providing greater comfort for the user, and the first knit layer 910 (that forms the outer-facing side) comprises the melted and re-flowed polymer in the fusible yarn, which provides rigidity, protection, and weatherization for the outer surface of the knit heel counter. In other examples, additionally or alternatively, the first knit layer may include a TPU yarn, and as such, when processed, the first knit layer may include the melted and re-flowed polymer from the fusible and/or TPU yarns.

In some aspects, there may be yarn transfers between the first knit layer 910 and the second knit layer 912, as indicated by dashed transfer line 913. For example, a yarn from the first knit layer 910 may be intermittently transferred to the second knit layer 912 where it may be knit in one or more knit loops of the second knit layer 912 before being transferred back to the first knit layer 910. In some aspects, a yarn from the second knit layer 912 may be intermittently transferred to the first knit layer 910 where it may be knit in one or more knit loops of the first knit layer 910 before being transferred back to the second knit layer 912. In some aspects, the transferred yarn may be a non-fusible yarn that is plated with a fusible yarn, e.g., a yarn that includes a thermoplastic polymer or other material(s) that can be heated, melted, re-flowed, and then cooled into a different solidified shape, disbursement, or geometry. The transfer of yarns in this fashion can facilitate the positioning of a fusible yarn, e.g., that is subsequently fused, on an exterior-facing surface to help reduce or limit stretch and/or elasticity on such surfaces.

The knit heel elements described herein can be configured to provide integrated rigidity, stiffness, and support, which can take the place of a traditional heel counter that otherwise requires the incorporation of additional elements such as stiffening materials (e.g., pre-formed injection molded heel-counter pieces, pre-formed die-cut and shaped heel counters, and the like), collar foam, collar lining, adhesives, and/or coupling elements that are typically added to a heel portion of an upper during a footwear making process. In order to provide desired stiffness and support, thermoplastic materials can be incorporated via knitting, e.g., in the first knit zone 138. In one example, the thermoplastic materials can be incorporated by including one or more of a TPU yarn and a fusible yarn in between the first knit layer 910 and the second knit layer 912. In a non-limiting example, the one or more of the TPU yarn and the fusible yarn may be floated in between the first and second layers and tucked to one or more of the first and second knit layers. In one example, an amount of fusible polymer is less than an amount of TPU polymer. For example, this can be accomplished by incorporating a greater number of ends of yarns with TPU, and a lesser number of ends of yarns with fusible polymer, in a knit heel element. The knit heel element is then post-processed to form a thermoformed layer 914. The aforementioned configuration and process for forming the same can significantly reduce the number of manufacturing steps and separate components required to produce footwear with these heel characteristics, reduce manufacturing time, and thus increase the sustainability of footwear manufacturing.

In the first knit zone 138, a thermoformed layer 914 is at least partially positioned between the first knit layer 910 and the second knit layer 912. The thermoformed layer 914 is formed from a thermoplastic material such as, for example, TPU, TPE, PET, and/or polyamide. In example aspects, the thermoformed layer 914 may at least partially penetrate the first knit layer 910 and/or the second knit layer 912. In example aspects, the thermoformed layer 914 may fully penetrate the first knit layer 910 such that the thermoplastic material of the thermoformed layer 914 is deposited on the outer-facing surface 116 of the knit heel element 114, as indicated by reference numeral 916. The deposit may be continuous or discontinuous in example aspects. In example aspects, the thermoformed layer 914 may fully penetrate the second knit layer 912, although in other aspects, it may not fully penetrate the second knit layer 912. The thermoformed layer 914 imparts rigidity or hardness to the second knit structure 900 in the first knit zone 138, which may help to provide support to, for example, a wearer's Achilles' tendon when the knit heel element 114 is incorporated into an article of footwear.

In some aspects, the first knit zone 138 in the second knit structure 900 may further include one or more yarn ends of a cushioning yarn 918 positioned between the first knit layer 910 and the second knit layer 912 and further positioned within the thermoformed layer 914. In one example aspect, there may be just one yarn end of the cushioning yarn 918, although aspects herein contemplate that there may be more than one yarn end of the cushioning yarn 918. In another example aspect, there may be zero yarn ends of the cushioning yarn 918. That is, the first knit zone 138 may not include a cushioning yarn between the first knit layer 910 and the second knit layer 912; however, the second knit layer 912 may include a textured yarn (e.g., chenille, peached polyester yarn, or the like) to provide a softer hand to the skin-facing side.

In example aspects, and as shown, the cushioning yarn 918 may be inlaid between the first knit layer 910 and the second knit layer 912. For smaller diameter cushioning yarns, the cushioning yarn 918 may be knit into one or more of the first knit layer 910 and the second knit layer 912 using, for example, intermittent tucks and floats. In example aspects, the yarn ends of the cushioning yarn 918 may help to space apart the first knit layer 910 from the second knit layer 912 based on the large diameter of the cushioning yarn 918 such that the thermoformed layer 914 has an increased thickness compared to if a cushioning yarn was not incorporated into the first knit zone 138.

In example aspects, the second knit structure 900 may further include at least one end of a high-melting yarn 920 such as a high-melting polyester yarn positioned between the first knit layer 910 and the second knit layer 912 and within the thermoformed layer 914. As described below, the high-melting yarn 920 may have previously been the core of a core/sheath yarn that existed prior to thermoforming. In the first knit zone 138, the sheath of the core/sheath yarn may have comprised the low-melting thermoplastic polymer material that melted to at least partially form the thermoformed layer 914, leaving the core of the high-melting yarn 920 subsequent to thermoforming. In example aspects, the high-melting yarn 920 may be interlooped and/or tucked with one or more yarn loops of the first knit layer 910 and the second knit layer 912 as shown in FIG. 5. In other aspects, the high-melting yarn 920 may be inlaid similar to the cushioning yarn 918. In example aspects, the high-melting yarn 920 and the cushioning yarn 918 may act as scaffolding around which the thermoformed layer 914 is formed. In this aspect, the high-melting yarn 920 and the cushioning yarn 918 may add structural stability to the first knit zone 138 and may further contribute to the rigidity and/or hardness of the first knit zone 138.

FIG. 10 schematically depicts the second knit structure 900 at the second knit zone 140 of the knit heel element 114. The second knit structure 900 at the second knit zone 140 includes the first knit layer 910, the second knit layer 912, the transfers 913 between the first knit layer 910 and the second knit layer 912, and the cushioning yarn 918 inlaid between the first knit layer 910 and the second knit layer 912. The transfers 913 can help lock the cushioning yarn in place and can expose some portions of the cushioning yarn on an outer surface, which can enhance the softness of the outer surface. The transfers 913 can also help contain and/or limit the expansion of the cushioning yarn in the second knit structure 900. The discussion of these elements provided for FIG. 9 also applies to FIG. 10. Instead of the thermoformed layer 914 at least partially positioned between the first knit layer 910 and the second knit layer 912 in the first knit zone 138, a number of yarn ends of a low-melting thermoplastic yarn 1010 are positioned between the first knit layer 910 and the second knit layer 912. In one example aspect, the number of yarn ends of the low-melting thermoplastic yarn 1010 include five yarn ends although fewer yarn ends (including zero yarn ends) or greater yarn ends are contemplated herein. For example, in aspects, in the first knit zone 138, four ends of cushioning yarn may be present, and in a cushioning area of the second knit zone 140, some regions may have four ends of cushioning yarn, and other regions, e.g., closer to the collar 130, may have one to three ends of cushioning yarn. In some example aspects, the number of yarn ends of the low-melting thermoplastic yarn 1010 include five yarn ends although fewer yarn ends (including zero yarn ends) or greater yarn ends are contemplated herein. For example, in aspects, in the first knit zone 138, zero ends of cushioning yarn may be present, and in a cushioning area of the second knit zone 140, some regions may have one to five ends of cushioning yarn, and other regions, e.g., closer to the collar 130, may have zero to three ends of cushioning yarn. In example aspects, low-melting thermoplastic yarn(s) 1010 can include fusible yarns formed entirely of a low-melting material such as low-melting PET and/or low-melting polyamide. In example aspects, the second knit zone 140 may not include yarns having a high-melting material (e.g., high-melting PET) and a low-melting thermoplastic material (e.g., TPU and/or TPE). In example aspects, low-melting thermoplastic yarn(s) 1010 can include fusible yarns formed entirely of a low-melting material such as low-melting PET and/or low-melting polyamide. In example aspects, the second knit zone 140 may not include yarns having a core of a high-melting material (e.g., high-melting PET) and a low-melting thermoplastic material (e.g., TPU and/or TPE). For example, the second knit zone 140 may instead include yarns formed entirely of a low-melting thermoplastic material (e.g., TPU and/or TPE). These yarns, when fused so as to be melted, re-flowed, and then re-solidified can then occupy spaces between the cushioning yarn without substantially limiting or constricting the cushioning yarn's padding or cushioning properties. The fused yarn can help keep a cushioning yarn in place during a knitting process.

Aspects herein contemplate that the yarn ends of the low-melting thermoplastic yarn 1010 may be interlooped with one or more yarns in the first knit layer 910 and the second knit layer 912 as shown by the zig-zag configuration in FIG. 10. In this aspect, the yarn ends of the low-melting thermoplastic yarn 1010 may be intermittently floated and tucked into the first knit layer 910 and the second knit layer 912. The combination of the cushioning yarn 918 and the low-melting thermoplastic yarn(s) 1010 may help to space apart the first knit layer 910 from the second knit layer 912, which may contribute to the cushioning properties of the knit heel element 114 in the second knit zone 140. In example aspects, the transfers 913 and/or the tucks of the low-melting thermoplastic yarn 1010 may be used to modulate the amount of cushioning provided by the cushioning yarns 918. For example, a greater number of transfers and/or tucks per inch or centimeter will provide a more dense cushioning structure, and a smaller number of transfers and/or tucks per inch or centimeter will provide a less dense (e.g., loftier) cushioning structure.

FIG. 11 depicts a block diagram of an example method 1100 of manufacturing a knit heel element, such as the knit heel element 114 using the second knit structure 900, in accordance with aspects herein. In block 1110, a first knit layer, such as the first knit layer 910 and a second knit layer, such as the second knit layer 912, are knit on a knitting machine during a single knitting event. The knit heel element may be knit to shape such that no additional trimming or cutting is needed. In other aspects, additional cutting or trimming may be needed to form the knit heel element. The first knit layer and the second knit layer may be knit on opposing beds of a knitting machine. The first and second knit layers may be knit using, for example, a high-melting thermoplastic yarn such as a high-melting PET yarn, and/or a high-melting recycled PET yarn. In example aspects, the high-melting yarn may be plated with a fusible yarn to impart additional structure and stability to the first and second knit layers.

In block 1112, yarn ends comprising a low-melting thermoplastic material, such as the yarn ends 1010, may be positioned between the first knit layer and the second knit layer. In this aspect, the yarn ends comprising the low-melting thermoplastic material may comprise fusible yarns, and the number of yarn ends may be five yarn ends. In example aspects, the yarn ends comprising the low-melting thermoplastic material may be interlooped with yarns in the first knit layer and the second knit layer using tucks and floats, for example. Aspects herein contemplate that the yarn ends comprising the low-melting thermoplastic material may be zonally positioned based on a desired end function. For example, in knit zones of the knit element for which a greater hardness or rigidity is desired, such as the first knit zone 138, a greater number of yarn ends of the thermoplastic material may be positioned between the first and second knit layers. In knit zones of the knit element for which a greater amount of cushioning is desired, such as the second knit zone 140, a fewer number of yarn ends comprising the thermoplastic material, including zero yarn ends, may be positioned between the first and second knit layers.

In block 1112, one or more yarn ends of a core/sheath yarn having a high-melting core and a low-melting sheath of thermoplastic material may be positioned between the first knit layer and the second knit layer. In example aspects, the core/sheath yarn may be zonally positioned based on a desired end function. For example, to impart an additional level of structural stability and/or rigidity to a particular knit zone, the core/sheath yarn may be positioned in areas of the knit heel element corresponding to the first knit zone. In line with this, the core/sheath yarn may not be zonally positioned in areas of the knit heel element corresponding to the second knit zone.

In block 1114, yarn ends comprising a cushioning yarn such as the cushioning yarn 918 are positioned between the first knit layer and the second knit layer. In one example aspect, the yarn ends may comprise one yarn end, although a greater number of yarn ends are contemplated herein. For cushioning yarns having a diameter above a certain threshold, the cushioning yarns may be inlaid. Otherwise, they may be interlooped with yarns in the first knit layer and the second knit layer. In one example aspect, the yarn ends of the cushioning yarn may be uniformly positioned throughout the knit heel element. Other aspects herein contemplate that the yarn ends of the cushioning yarn may be zonally positioned based on a desired end function. For example, in knit zones of the knit element for which a higher degree of cushion is desired, such as the second knit zone 140, a greater number of yarn ends of the cushioning yarn may be positioned between the first and second knit layers.

Aspects herein further contemplate that the amount of cushioning imparted by the cushioning yarns may be modulated by the transfers and/or tucks, such as the transfers 913, between the first knit layer and the second knit layer and/or the tucks of the low-melting thermoplastic yarns. For example, a greater number of transfers and/or tucks per inch or centimeter may compress the cushioning yarns resulting in less cushion and/or a denser cushion. Conversely, a fewer number of transfers and/or tucks per inch or centimeter may result in greater cushion or less dense cushion.

Like blocks 810, 812, and 814 of the method 800, blocks 1110, 1112, and 1114 of the method 1100 are described separately above to discuss particular details of each aspect of the knit structure. However, it should be understood that these steps may occur simultaneously, such that the high-melting yarns for the first knit layer and the second knit layer, yarn(s), the low-melting thermoplastic yarns, the core/sheath yarn, and the cushioning yarn may be knit across needle beds within a single pass of a carriage using multiple feeders.

In block 1116, one or more of heat at a first temperature and pressure are applied to a first knit zone, such as the first knit zone 138 of the knit heel element. In example aspects, the heat at the first temperature and the pressure may be applied while the knit heel element is in a flat, planar state (also known as flat-pressing). The heat may be at a temperature sufficient to melt the thermoplastic material of the yarns positioned between the first knit layer and the second knit layer (e.g., the fusible yarns and the thermoplastic sheath of the core/sheath yarn) but not high enough to damage the high-melting yarns, including the yarns used to form the first and second knit layers, the core of the core/sheath yarn, and/or the cushioning yarn. An example temperature may include, for example, about 135 degrees Celsius. The applied pressure causes the melted thermoplastic material to flow between the first and second knit layers.

In block 1118, the knit heel element is cooled. When cooled, a thermoformed layer, such as the thermoformed layer 914, is formed between the first and second knit layers in the first knit zone of the knit heel element. In some aspects, the pressure may be sufficient to cause the thermoplastic material to penetrate into or through the first knit layer and/or the second knit layer. In example aspects, the heat at the first temperature and the pressure are not applied to a second knit zone, such as the second knit zone 140, such that a thermoformed layer is not formed in the second knit zone.

In block 1120, the cooled knit heel element is positioned on a three-dimensional (3-D) form, such as a heel area of a shoe last. In example aspects, the 3-D form may be put in a vacuum chamber. In block 1122, heat at a second temperature and pressure are applied to an entirety of the knit heel element. In example aspects, the heat at the second temperature may be sufficient to soften the thermoformed layer and/or to soften the yarn ends comprising the thermoplastic material such as the yarn ends 1010, but not melt the thermoplastic material. In example aspects, the heat at the second temperature may be from about 70 degrees Celsius to about 100 degrees Celsius. While the thermoplastic material is softened, pressure is applied to the knit heel element to cause the knit heel element to conform to the shape of the 3-D form. In one example, the pressure may be imparted by sand that is poured over the 3-D form. The use of sand may ensure a more even distribution of pressure to the knit heel element such that an entirety of the knit heel element closely conforms to the three-dimensional shape of the 3-D form.

After removing the knit heel element from the 3-D form and cooling the knit heel element, the knit heel element is incorporated into an article of footwear at block 1124. For example, the knit heel element is incorporated into a heel area and a heel region, such as the heel region 124 and the heel area 125 of an article of footwear, such as the article of footwear 100. The knit heel element is positioned such that the first knit zone is located adjacent the sole structure and the second knit zone is located adjacent the collar of the article of footwear.

FIG. 12 depicts an array of articles of footwear, including a first article of footwear 1210 and a second article of footwear 1212. In example aspects, the first article of footwear 1210 includes an upper 1214 secured to a sole structure 1216. The first article of footwear 1210 further includes a first knit heel element 1218 having a first knit zone 1220, a second knit zone 1222, and a collar 1223, which may be knit using the first knit structure 500 or the second knit structure 900. In example aspects, the first article of footwear 1210 is configured for a first category of sporting activity. In the illustrative example shown in FIG. 12, the first category of sporting activity may comprise basketball, although this is just one example. With respect to articles of footwear configured for basketball, in general the collar of the article of footwear extends farther up a wearer's foot compared to articles of footwear for running, global football, and the like (e.g., so-called high-top shoes). Because the collar 1223 extends farther up and may be positioned around the ankle malleoli of the wearer, an increased amount of cushioning and/or an increased cushioning area may be needed to protect the sensitive skin around the malleoli. An isolated view of the first knit heel element 1218 is depicted below the first article of footwear 1210.

In example aspects, the second article of footwear 1212 includes an upper 1224 secured to a sole structure 1226. The second article of footwear 1212 further includes a second knit heel element 1227 having a third knit zone 1228, which corresponds to the first knit zone 138; a fourth knit zone 1230, which corresponds to the second knit zone 140; and a collar 1231, which may be knit using the first knit structure 500 or the second knit structure 900. In example aspects, the second article of footwear 1212 is configured for a second category of sporting activity different from the first category of sporting activity. In the illustrative example shown in FIG. 12, the second category of sporting activity may include global football, although this is just one example. In articles of footwear configured for global football, in general the collar 1231 is positioned below the ankle malleoli, and there may be an increased need for rigidity or support in the heel area to support the wearer's Achilles' tendon and heel area when the wearer executes various maneuvers. An isolated view of the second knit heel element 1227 is depicted below the second article of footwear 1212.

By using either the first knit structure 500 or the second knit structure 900, the different knit zones of the articles of footwear 1210 and 1212 may be customized to meet the different requirements of the different sporting activities. For example, with respect to the first article of footwear 1210 with its increased need for cushioning to protect the ankle malleoli of the wearer, the second knit zone 1222 may include a greater number of yarn ends of cushioning yarn or a fewer number of yarn ends of yarns comprising a thermoplastic material (including zero yarn ends of yarns comprising a thermoplastic material). Additionally or alternatively, the size or surface area of the second knit zone 1222 may be increased relative to the first knit zone 1220 to provide a greater amount of cushioning. In another example, the number of transfers between the knit layers (e.g., the first, second, and third knit layers in the first knit structure or the first and second knit layers in the second knit structure) may be reduced to increase the amount or loft of cushioning in the second knit zone 1222.

With respect to the second article of footwear 1212 with its increased need for rigidity or hardness in the third knit zone 1228, the third knit zone 1228 may include a greater number of yarn ends of yarns comprising a thermoplastic material such that a thicker or denser thermoformed layer is formed. In addition, the number of cushioning yarns in the third knit zone 1228 may be reduced if needed. Additionally or alternatively, the size or surface area of the third knit zone 1228 may be increased relative to the fourth knit zone 1230 to provide a greater surface area of rigidity or hardness.

In aspects, an upper and/or article of footwear comprise a knit element. The knit element includes a knit heel element. The knit heel element is thermoformed and/or at least partially fused to thereby comprise a layer of thermoformed and/or fused polymer material that provides increased stiffness. The layer of increased stiffness forms an integrally knit-in heel counter. The knit-in heel counter provides stiffness in a heel region without separate components of a traditional heel counter being inserted, attached, or incorporated, e.g., in additional manufacturing steps subsequent to a knitting operation that forms the knit element and thermoforming operation that forms the layer of increased stiffness.

- Aspect 1. A knit heel element, comprising: a first knit composite zone comprising a low-melting thermoplastic material and a first knit structure; a second knit composite zone integrally extending from the first knit composite zone, the second knit composite zone comprising the low-melting thermoplastic material and a second knit structure, wherein a concentration by weight of the low-melting thermoplastic material is less in the second knit composite zone compared to the first knit composite zone; and a knit collar integrally extending from the second knit composite zone, the knit collar comprising one or more elastic yarns.
- Aspect 2. The knit heel element of aspect 1, wherein the low-melting thermoplastic material is thermoformed, defining a heel counter having a higher stiffness than a remainder of the knit heel element.
- Aspect 3. The knit heel element of aspect 1 or 2, wherein the first knit structure comprises a first knit layer and a second knit layer.
- Aspect 4. The knit heel element of any of aspects 1-3, wherein the low-melting thermoplastic material in the first knit composite zone comprises a thermoformed layer.
- Aspect 5. The knit heel element of any of aspects 1-4, wherein the thermoformed layer is at least partially positioned between a first knit layer and a second knit layer of the first knit structure.
- Aspect 6. The knit heel element of any of aspects 1-5, wherein the thermoformed layer comprises at least one cushioning yarn.
- Aspect 7. The knit heel element of any of aspects 1-6, wherein the thermoformed layer comprises at least one high-melting thermoplastic yarn.
- Aspect 8. The knit heel element of any of aspects 1-7, wherein the second knit structure comprises at least a first knit layer and a second knit layer.
- Aspect 9. The knit heel element of any of aspects 1-8, wherein the second knit structure comprises a first number of yarn ends each formed entirely of a low-melting thermoplastic material positioned between the first knit layer and the second knit layer.
- Aspect 10. The knit heel element of any of aspects 1-9, wherein the second knit structure comprises a second number of yarn ends each comprising a cushioning yarn positioned between the first knit layer and the second knit layer, wherein the first number of yarn ends each formed entirely of the low-melting thermoplastic material are thermoformed, in an area between the first knit layer and the second knit layer.
- Aspect 11. The knit heel element of any of aspects 1-10, wherein the low-melting thermoplastic material that is thermoformed between the first knit layer and the second knit layer is interspersed among the second number of yarn ends each comprising a cushioning yarn.
- Aspect 12. A knit heel element, comprising: a first knit zone comprising a first hardness; a second knit zone integrally extending from the first knit zone, the second knit zone comprising a second hardness that is less than the first hardness; and a knit collar integrally extending from the second knit zone, the knit collar comprising one or more elastic yarns.
- Aspect 13. The knit heel element of aspect 12, wherein the first knit zone is positioned at a lower end of the knit heel element, and the second knit zone extends from the first knit zone upward to the knit collar.
- Aspect 14. The knit heel element of aspect 12 or 13, wherein the first knit zone comprises a first concentration of thermoplastic polymer material per unit of surface area, and wherein the second knit zone comprises a second concentration of thermoplastic polymer material per unit of surface area, and wherein the first concentration is higher than the second concentration.
- Aspect 15. The knit heel element of any of aspects 12-14, wherein the first knit zone and the second knit zone comprise a thermoformed layer.
- Aspect 16. The knit heel element of any of aspects 12-15, wherein the thermoformed layer defines a heel-counter that has a higher stiffness than a remaining portion of the knit heel element.
- Aspect 17. The knit heel element of any of aspects 12-16, wherein the higher stiffness of the heel-counter is provided without a separately-formed component being incorporated into or onto the knit heel element to increase stiffness.
- Aspect 18. An article of footwear, comprising: a sole structure; and an upper secured to the sole structure, the upper comprising a knit element comprising a first knit zone and a second knit zone, the first knit zone comprising: a first knit layer, a second knit layer, and a thermoformed layer located at least partially between the first knit layer and the second knit layer, the thermoformed layer comprising a low-melting thermoplastic material, and the second knit zone comprising: the first knit layer, the second knit layer, a first number of yarn ends comprising the low-melting thermoplastic material.
- Aspect 19. The article of footwear of aspect 18, wherein the upper comprises an integrally knitted heel-counter formed by the low-melting thermoplastic material that is thermoformed.
- Aspect 20. The article of footwear of aspect 18 or 19, wherein the integrally knitted heel-counter has a higher stiffness than a remainder of the knit element, without a separate component incorporated into or onto the knit element to increase stiffness.
- Aspect 21. The article of footwear of any of aspects 18-20, wherein the thermoformed layer comprises at least one end of a cushioning yarn, and wherein the second knit zone comprises a second number of yarn ends of a cushioning yarn.
- Aspect 22. The article of footwear of any of aspects 18-21, wherein the first knit layer and the second knit layer each comprise a high-melting thermoplastic yarn.
- Aspect 23. The article of footwear of any of aspects 18-22, wherein the thermoformed layer further comprises at least one end of a high-melting thermoplastic yarn.
- Aspect 24. The article of footwear of any of aspects 18-23, wherein, in the second knit zone, the first number of yarn ends comprising the low-melting thermoplastic material are each entirely formed of the low-melting thermoplastic material.
- Aspect 25. The article of footwear of any of aspects 18-24, wherein the first number of yarn ends comprising the low-melting thermoplastic material comprise one or more of a low-melting polyethylene terephthalate yarn and a low-melting polyamide yarn.
- Aspect 26. The article of footwear of any of aspects 18-25, wherein the first number of yarn ends comprising the low-melting thermoplastic material are the low-melting polyethylene terephthalate, and wherein a melting point of the low-melting polyethylene terephthalate yarn is less than or equal to about 135 degrees Celsius.
- Aspect 27. The article of footwear of any of aspects 18-26, wherein the first number of yarn ends comprising the low-melting thermoplastic material are the low-melting polyamide yarn, and wherein a melting point of the low-melting polyamide yarn is less than or equal to about 135 degrees Celsius.
- Aspect 28. The article of footwear of any of aspects 18-27, wherein the first number of yarn ends comprising the low-melting thermoplastic material in the second knit zone is five yarn ends.
- Aspect 29. The article of footwear of any of aspects 18-28, wherein a cushioning yarn is inlaid between the first knit layer and the second knit layer in the first knit zone.
- Aspect 30. The article of footwear of any of aspects 18-29, wherein the first number of yarn ends comprising the low-melting thermoplastic material in the second knit zone is intermittently interlooped with yarns forming one or more of the first knit layer and the second knit layer of the first knit zone.
- Aspect 31. The article of footwear of any of aspects 18-30, wherein the first knit zone includes a higher concentration per unit of surface area of the low-melting thermoplastic material than the second knit zone.
- Aspect 32. An array of articles of footwear each comprising a sole structure, an upper secured to the sole structure, and a knit heel element, each knit heel element comprising a first knit layer comprising an outer-facing surface of the knit heel element, and a second knit layer comprising an inner-facing surface of the knit heel element, the array of articles of footwear comprising at least: a first article of footwear configured for a first category of sporting activity, a first knit heel element of the first article of footwear comprising: a first knit zone located at a lower portion of the first knit heel element, the first knit zone comprising a thermoformed layer comprising a low-melting thermoplastic material and at least positioned between the first knit layer and the second knit layer, and a second knit zone located above the first knit zone, the second knit zone comprising a first number of yarn ends comprising the low-melting thermoplastic material and a second number of yarn ends comprising a cushioning yarn; and a second article of footwear configured for a second category of sporting activity different from the first category of sporting activity, a second knit heel element of the second article of footwear comprising: a third knit zone located at a lower portion of the second knit heel element, the third knit zone comprising a thermoformed layer comprising the low-melting thermoplastic material and at least partially positioned between the first knit layer and the second knit layer, and a fourth knit zone located above the third knit zone, the fourth knit zone comprising a third number of yarn ends comprising the low-melting thermoplastic material and a fourth number of yarn ends comprising a cushioning yarn, wherein the first knit zone of the first article of footwear and the third knit zone of the second article of footwear comprise different surface areas and/or the second knit zone of the first article of footwear and the fourth knit zone of the second article of footwear comprise different surface areas.
- Aspect 33. The array of articles of footwear of aspect 32, wherein the thermoformed layer of the first knit heel element defines a first heel-counter comprising a first stiffness that is higher than a stiffness of a remainder of the first knit zone and the second knit zone, and wherein the thermoformed layer of the second knit heel element defines a second heel-counter comprising a second stiffness that is higher than a stiffness of a remainder of the third knit zone and the fourth knit zone.
- Aspect 34. The array of articles of footwear of aspect 32 or 33, wherein the first stiffness and the second stiffness are different.
- Aspect 35. The array of articles of footwear of any of aspects 32-34, wherein the first heel-counter and the second heel-counter are each integrally formed with the first knit heel element and the second knit heel element, respectively, without a separate component being integrated therein or thereon for increasing stiffness.
- Aspect 36. The array of articles of footwear of any of aspects 32-35, wherein the thermoformed layer in each of the first knit zone of the first article of footwear and the third knit zone of the second article of footwear comprise at least one end of a high-melting thermoplastic yarn.
- Aspect 37. The array of articles of footwear of any of aspects 32-36, wherein each of the second number of yarn ends comprising the low-melting thermoplastic material in the second knit zone of the first article of footwear and the third number of yarn ends comprising the low-melting thermoplastic material in the fourth knit zone of the second article of footwear comprise one or more of a low-melting polyethylene terephthalate yarn and a low-melting polyamide yarn.
- Aspect 38. A method of manufacturing a knit element for an upper of an article of footwear, the method comprising: knitting a first knit layer and a second knit layer; positioning yarn ends comprising a low-melting thermoplastic material between the first knit layer and the second knit layer; positioning yarn ends comprising a cushioning yarn between the first knit layer and the second knit layer; and thermoforming at least a first knit zone of the knit element such that a thermoformed layer is formed at least partially between the first knit layer and the second knit layer, the thermoformed layer being located in a heel area.
- Aspect 39. The method of aspect 38, further comprising: forming the knit element into an upper, and incorporating the upper into an article of footwear, such that the thermoformed layer forms an integral heel-counter in the heel area of the article of footwear.
- Aspect 40. The method of aspect 38 or 39, wherein the integral heel-counter is formed without a separate component being integrated into or onto the heel area for increasing a stiffness of the heel area.
- Aspect 41. The method of any of aspects 38-40, wherein, during thermoforming, the heel area of the knit element is thermoformed into a three-dimensional shape.
- Aspect 42. An article of footwear comprising: a sole structure; and an upper secured to the sole structure, the upper comprising a knit element, the knit element comprising: a first knit layer comprising an outer-facing surface of the knit element, a second knit layer comprising an inner-facing surface of the knit element, and a third knit layer positioned between the first knit layer and the second knit layer, wherein: a thermoformed layer is at least partially positioned between the first knit layer and the third knit layer in at least a first knit zone of the knit element, and a first number of yarn ends comprising a cushioning yarn is positioned between the second knit layer and the third knit layer in at least a second knit zone of the knit element.
- Aspect 43. An array of articles of footwear each comprising a sole structure, an upper secured to the sole structure, and a knit heel element, each of the knit heel elements comprising a first knit layer comprising an outer-facing surface of the knit heel element, a second knit layer comprising an inner-facing surface of the knit heel element, and a third knit layer positioned between the first knit layer and the second knit layer, the array of articles of footwear comprising at least: a first article of footwear configured for a first category of sporting activity, a first knit heel element of the first article of footwear comprising: a first knit zone located at a lower portion of the first knit heel element, the first knit zone comprising a thermoformed layer at least partially positioned between the first knit layer and the third knit layer, and a second knit zone located at an upper portion of the first knit heel element, the second knit zone comprising a first number of yarn ends of a cushioning yarn positioned between the second knit layer and the third knit layer; and a second article of footwear configured for a second category of sporting activity different from the first category of sporting activity, a second knit heel element of the second article of footwear comprising: a third knit zone located at a lower portion of the second knit heel element, the third knit zone comprising a thermoformed layer at least partially positioned between the first knit layer and the third knit layer, and a fourth knit zone located at an upper portion of the second knit heel element, the fourth knit zone comprising a second number of yarn ends of a cushioning yarn positioned between the second knit layer and the third knit layer, wherein the first knit zone of the first article of footwear and the third knit zone of the second article of footwear comprise different surface areas, and/or the second knit zone of the first article of footwear and the fourth knit zone of the second article of footwear comprise different surface areas.
- Aspect 44. A method of manufacturing a knit element for an upper, the method comprising: knitting on a knitting machine a first knit layer, a second knit layer, and a third knit layer, the third knit layer positioned between the first knit layer and the second knit layer; positioning one or more yarn ends comprising a low-melting thermoplastic material between the first knit layer and the third knit layer; and positioning one or more yarn ends comprising a cushioning yarn between the second knit layer and the third knit layer.
- Aspect 45. An article of footwear comprising: a sole structure; and an upper secured to the sole structure, the upper comprising a knit element, having a first knit zone and a second knit zone, the first knit zone comprising: a first knit layer, a second knit layer, and a thermoformed layer at least partially between the first knit layer and the second knit layer, the thermoformed layer comprising low-melting thermoplastic material and at least one end of a cushioning yarn, the second knit zone comprising: the first knit layer, the second knit layer, a first number of yarn ends comprising the low-melting thermoplastic material, and a second number of yarn ends comprising the cushioning yarn.
- Aspect 46. A knit heel element comprising: a lower edge; an upper edge; a first side edge joining a first end of the lower edge to a first end of the upper edge; a second side edge joining a second end of the lower edge to a second end of the upper edge; a first knit zone extending upward from the lower edge and terminating in a first knit zone upper edge; a second knit zone extending upward from the first knit zone upper edge and terminating in a second knit zone upper edge, wherein: a first distance between the first knit zone upper edge and the second knit zone upper edge is greater at the first side edge and the second side edge of the knit heel element compared to a second distance between the first knit zone upper edge and the second knit zone upper edge at a vertical midline of the knit heel element.
- Aspect 47. A method of manufacturing, forming, and/or assembling any of the aspects 1-46 or other aspects described herein in this disclosure.

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 sub-combinations are of utility and may be employed without reference to other features and sub-combinations 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

KNIT ELEMENT WITH CUSHIONING AND RIGIDITY ZONES, UPPERS AND FOOTWEAR WITH THE SAME, AND METHODS OF MANUFACTURING THE SAME

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