ARTICLE OF APPAREL WITH COMFORT STRAP

FIELD

The present disclosure relates to the field of apparel, and particularly to garments, padding, bags or other products configured to be worn or carried on the body.

BACKGROUND

Many garments and other articles of apparel are designed to fit closely to the human body. When designing an article of apparel for a close fit to the human body, different body shapes and sizes must be considered. Different individuals within a particular garment size will have different body shapes and sizes. For example, two individuals wearing the same shoe size may have very differently shaped heels. As another example, two individuals wearing the same shirt size may have very different chest to abdomen dimensions. These variable measurements between similarly sized individuals makes proper design of closely fitting garments difficult.

In addition to accounting for different body measurements for different individuals within a size, various contours of the human body must also be considered when designing closely fitting articles of apparel configured to closely engage the human body. These contours of the human body often include various double curvature surfaces. Spheroids, bowls, and saddle-backs are all examples of surfaces having double curvatures. If a garment or other article of apparel is not properly sized for a particular wearer, the wearer may experience undesirable tightness or looseness at various locations. Such an improper fit may result in discomfort, excessive wear, or bending or creasing of the garment at the poorly fitting locations.

In view of the foregoing, it would be desirable to provide a garment or other article of apparel capable of conforming to various body shapes within a given size range. It would also be desirable to provide a garment or other article of apparel that is capable of conforming to various double curvatures on the human body. In addition, it would be desirable for such a garment or article of apparel to be relatively inexpensive and easy to manufacture.

SUMMARY

In accordance with one exemplary embodiment of the disclosure, there is provided a backpack comprising a bag portion and at least one shoulder strap coupled to the bag portion. The at least one shoulder strap includes a non-elastic first strap portion coupled to an elastic second strap portion, wherein a Poisson's ratio of the second strap portion is less than a Poisson's ratio of the first strap portion.

Pursuant to another exemplary embodiment of the disclosure, there is provided a backpack comprising a bag portion comprising a plurality of panels, the plurality of panels including a non-elastic first panel and an elastic second panel, wherein a Poisson's ratio of the second panel is less than a Poisson's ratio of the first panel. At least one shoulder strap coupled to the bag portion.

In accordance with yet another exemplary embodiment of the disclosure, there is provided a bag comprising a bag portion and at least one shoulder strap coupled to the bag portion. The at least one shoulder strap includes a non-elastic first strap portion coupled to an elastic second strap portion, wherein the second strap portion is comprised of an auxetic structure.

The above described features and advantages, as well as others, will become more readily apparent to those of ordinary skill in the art by reference to the following detailed description and accompanying drawings. While it would be desirable to provide an article of apparel that provides one or more of these or other advantageous features, the teachings disclosed herein extend to those embodiments which fall within the scope of the appended claims, regardless of whether they accomplish one or more of the above-mentioned advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a plan view of an auxetic structure including segments and voids forming a plurality of reentrant shapes;

FIG. 1B shows a plan view of the auxetic structure of FIG. 1A in an expanded position;

FIG. 2A shows a panel of an article of apparel including an auxetic arrangement with the auxetic structure of FIG. 1A;

FIG. 2B shows dimensions of the auxetic arrangement of FIG. 2A;

FIG. 2C shows a cross-sectional view of an exemplary embodiment of the auxetic arrangement of FIG. 2A;

FIG. 2D shows a cross-sectional view of an exemplary embodiment of the auxetic arrangement of FIG. 2A further including a foam layer;

FIG. 2E shows a cross-sectional view of another exemplary embodiment of the auxetic arrangement of FIG. 2A further including another foam layer;

FIG. 2F shows a cross-sectional view of another exemplary embodiment of the auxetic arrangement of FIG. 2A further including a second elastic layer;

FIG. 2G shows a cross-sectional view of another exemplary embodiment of the auxetic arrangement of FIG. 2A further including a second elastic layer with interconnections of the elastic layers in the voids of the auxetic structure;

FIG. 2H shows a cross-sectional view of another exemplary embodiment of the auxetic arrangement of FIG. 2A further including a dual layer auxetic arrangement;

FIG. 2I shows a cross-sectional view of another exemplary embodiment of the auxetic arrangement of FIG. 2A further including a foam layer extending into voids in the auxetic structure;

FIG. 2J shows a cross-sectional view of another exemplary embodiment of the auxetic arrangement of FIG. 2A further including a foam layer extending into voids in the auxetic structure and forming a substantially smooth outer surface with the segments of the auxetic layer;

FIG. 3A shows a plan view of an alternative embodiment of the auxetic structure of FIG. 1A;

FIG. 3B shows a plan view of another alternative embodiment of the auxetic structure of FIGS. 3A and 3B;

FIG. 4A shows a perspective view of an article of apparel incorporating the auxetic arrangement of FIG. 2A in a cap;

FIG. 4B shows a side view of the cap of FIG. 4A;

FIG. 4C shows a bottom perspective view of the cap of FIG. 4B;

FIG. 5A shows a side view of an article of apparel incorporating the auxetic arrangement of FIG. 2A in a shoe upper;

FIG. 5B shows a front perspective view of the shoe upper of FIG. 5A;

FIG. 5C shows a rear perspective view of the shoe upper of FIG. 5A;

FIG. 5D shows a rear view of the shoe upper of FIG. 5A;

FIG. 6A shows a side perspective view of the shoe upper of FIG. 5A in a flexed position;

FIG. 6B shows a front perspective view of the shoe upper of FIG. 5B in a flexed position;

FIG. 7A shows a side perspective view of an article of apparel incorporating the auxetic arrangement of FIG. 2A in a midsole and heel portion of a shoe upper;

FIG. 7B shows a rear view of the shoe upper of FIG. 7A;

FIG. 7C shows a side perspective view of an article of apparel incorporating the auxetic arrangement of FIG. 2A in a midsole portion of a shoe upper;

FIG. 8A shows a side perspective view of an article of apparel incorporating the auxetic arrangement of FIG. 2A in an ankle portion of a shoe upper for a high-top cleat;

FIG. 8B shows a front perspective view of the high-top cleat of FIG. 8A;

FIG. 8C shows a rear view of the high-top cleat of FIG. 8A;

FIG. 9A shows a front view of an article of apparel incorporating the auxetic arrangement of FIG. 2A in a garment, and particularly a shirt;

FIG. 9B shows a rear view of the shirt of FIG. 9A;

FIG. 9C shows a side view of an article of apparel incorporating the auxetic arrangement of FIG. 2A in an arm sleeve;

FIG. 10A shows a front view of an article of apparel incorporating the auxetic arrangement of FIG. 2A in a garment, and particularly a short;

FIG. 10B shows a side view of the short of FIG. 10A;

FIG. 10C shows a front view of an article of apparel incorporating the auxetic arrangement of FIG. 2A in a leg sleeve;

FIG. 11A shows a front view of an article of apparel incorporating the auxetic arrangement of FIG. 2A in a baseball chest protector;

FIG. 11B shows a front perspective view of an article of apparel incorporating the auxetic arrangement of FIG. 2A in a soccer shin guard;

FIG. 11C shows a side perspective view of an article of apparel incorporating the auxetic arrangement of FIG. 2A in a girdle with protective pads;

FIG. 12 shows a front perspective view of an article of apparel incorporating the auxetic arrangement of FIG. 2A in a backpack;

FIG. 13A shows a plan view of an article of apparel incorporating the auxetic arrangement of FIG. 2A in a shoulder pad for a strap of a carrying bag;

FIG. 13B shows a side view of the shoulder pad of FIG. 13A and an associated strap;

FIG. 14A shows a plan view of an article of apparel incorporating the auxetic arrangement of FIG. 2A in an alternative embodiment of a shoulder pad for a strap of a carrying bag;

FIG. 14B shows a cross-sectional view of the shoulder pad of FIG. 14A configured for use with the shoulder strap;

FIG. 14C shows a front perspective view of the shoulder strap of FIG. 14B;

FIG. 14D shows a side view of the shoulder pad of FIG. 14A and an associated strap.

FIG. 15 discloses a front perspective view of a backpack with elastic straps and lockout webbing;

FIG. 16 shows a rear perspective view of the backpack of FIG. 15:

FIG. 17 shows a side view of the backpack of FIG. 15;

FIG. 18 shows a front view of the backpack of FIG. 15;

FIG. 19 shows an enlarged perspective view of an elastic strap of the backpack of FIG. 15 in isolation from the lockout webbing;

FIG. 20 shows a user holding an elastic strap of the backpack of FIG. 15 in a relaxed position;

FIG. 21 shows the user holding the elastic strap of FIG. 20 in a stretched position:

FIG. 22 shows a front view of an alternative embodiment of the backpack of FIG. 15 included a split corrugated forward panel; and

FIG. 23 shows a front view of another alternative embodiment of the backpack of FIG. 15 including a full corrugated forward panel.

DESCRIPTION

In the following detailed description, reference is made to the accompanying figures which form a part hereof wherein like numerals designate like parts throughout, and in which is shown, by way of illustration, embodiments that may be practiced. It is to be understood that other embodiments may be utilized, and structural or logical changes may be made without departing from the scope of the present disclosure. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of embodiments is defined by the appended claims and their equivalents.

Aspects of the disclosure are disclosed in the accompanying description. Alternate embodiments of the present disclosure and their equivalents may be devised without parting from the spirit or scope of the present disclosure. It should be noted that any discussion herein regarding “one embodiment”, “an embodiment”, “an exemplary embodiment”, and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, and that such particular feature, structure, or characteristic may not necessarily be included in every embodiment. In addition, references to the foregoing do not necessarily comprise a reference to the same embodiment. Finally, irrespective of whether it is explicitly described, one of ordinary skill in the art would readily appreciate that each of the particular features, structures, or characteristics of the given embodiments may be utilized in connection or combination with those of any other embodiment discussed herein.

Various operations may be described as multiple discrete actions or operations in turn, in a manner that is most helpful in understanding the claimed subject matter. However, the order of description should not be construed as to imply that these operations are necessarily order dependent. In particular, these operations may not be per-formed in the order of presentation. Operations described may be performed in a different order than the described embodiment. Various additional operations may be performed and/or described operations may be omitted in additional embodiments.

For the purposes of the present disclosure, the phrase “A and/or B” means (A), (B), or (A and B). For the purposes of the present disclosure, the phrase “A, B, and/or C” means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).

The terms “comprising,” “including,” “having,” and the like, as used with respect to embodiments of the present disclosure, are synonymous.

As described herein, an article of apparel includes an auxetic structure incorporated therein. The term “article of apparel” as used herein refers to any garment, footwear or accessory configured to be worn on or carried by a human. Examples of articles of apparel include helmets, hats, caps, shirts, pants, shorts, sleeves, knee pads, elbow pads, shoes, boots, backpacks, duffel bags, cinch sacks, and straps, as well as numerous other products configured to be worn on or carried by a person.

As used herein, a “backpack” refers to bag with at least one strap connected thereto with the bag designed to be carried on the back of a human user. The illustrated embodiments depict backpacks with dual straps and bags designed to engage the back of the user, but the reader will appreciate that the embodiments described herein may be used with any desired bag with an attached strap.

The term “auxetic” as used herein generally refers to a material or structure possessing a negative Poisson's ratio. In other words, when stretched, auxetic materials expand, becoming thicker (as opposed to thinner), in a direction perpendicular to the applied force. In at least one embodiment, this expansion occurs due to inherent hinge-like structures within the materials which flex when stretched. In contrast, materials with a positive Poisson's ratio contract in a direction perpendicular to the applied force.

Exemplary Auxetic Structures

One exemplary auxetic structure 10 is shown in FIGS. 1A and 1B. The auxetic structure 10 is provided by a plurality of generally-polygon-shaped cells (e.g., hourglass or bow-tie shaped cells, which may also be referred to as “auxetic hexagons”). The cells are oriented in an array, being positioned in horizontal rows and vertical columns. FIG. 1A shows the auxetic structure 10 in its normal, unstretched state. The thickness (or width) of the auxetic structure in the unstretched state is indicated as d1. FIG. 1B shows the auxetic structure 10 stretched in the direction of arrows 12. The thickness of the auxetic structure in the stretched state is indicated by d2. As can be seen in FIG. 1B, when tension is applied along a first direction (indicated by arrows 12), the auxetic structure is stretched, expanding (becoming thicker) in a second direction perpendicular to the first direction 12 (indicated by arrows 13) such that, in the stretched state d2>d1. In the embodiment of FIGS. 1A and 1B, this phenomena is the result of the pivoting/rotation that occurs along the vertices of the shape, i.e., where the corners of the polygon intersect.

It will be recognized that whether a structure has a negative Poisson's ratio, may depend upon the degree to which the structure is stretched. Structures may have a negative Poisson's ratio up to a certain stretch threshold, but when stretched past the threshold may have a positive Poisson's ratio. For example, it is possible that when the auxetic structure 10 in FIG. 1A is stretched in the direction of arrows 12 past a threshold expansion position (e.g., past the state shown in FIG. 1B), the cells and segments of the auxetic structure 10 may be stretched to an extent that the auxetic structure 10 becomes slightly thinner (in the direction perpendicular to arrows 12) before the structure is torn apart or otherwise damaged. Accordingly, the term “auxetic” as used herein refers to structures or materials that possess or exhibit a negative (below zero) Poisson's ratio at some point during stretch. Preferably, the structure or material possesses a negative Poisson's ratio during the entirety of the stretch. The term “near auxetic,” moreover, is used herein to refer to a structure having a Poisson's ratio of approximately zero and, in particular, less than +0.15 (i.e., from about 0 to +0.15).

Auxetic structures are formed from a plurality of interconnected segments forming an array of cells, and each cell having a reentrant shape. In the field of geometry, a reentrant shape may also be referred to as a “concave”, or “non-convex” polygon or shape, which is a shape having an interior angle with a measure that is greater than 180°. The auxetic structure 10 in FIGS. 1A and 1B is an example of such a structure including a reentrant shape. As shown, angle α possesses a measurement of greater than 180°.

Auxetic structures may be defined by two different elongation directions, namely, a primary elongation direction and a secondary elongation direction. The primary elongation direction is a first direction along which the cells of the auxetic structure are generally arranged, and the secondary elongation direction is the direction perpendicular to the first direction, the cells of the auxetic structure also being arranged along this second direction. For example, in FIGS. 1A and 1B, the horizontal arrows 12 (from the viewpoint of FIG. 1B define the primary elongation direction, while vertical arrows 13 (from the viewpoint of FIG. 1B) define the secondary elongation direction. When a tension force elongates the auxetic structure 10 in the primary elongation direction, the auxetic structure is also elongated in the secondary elongation direction. Similarly, applying tension to the auxetic structure 10 in the secondary elongation direction will result in elongation in the primary elongation direction.

The total number of cells, the shape of each shell, and the overall arrangement of the cells within the structure generate the expansion pattern of the auxetic structure. That is, the arrangement and shape of the cells determine whether the auxetic structure 10 expands a greater amount in the primary elongation direction or the secondary elongation direction.

It is worth noting that the phrases “primary elongation direction” and “secondary elongation direction” as used herein do not necessarily indicate that the auxetic structure 10 elongates further in one direction or the other, but is merely used to indicate two general directions of elongation for the auxetic structure as defined by the cells, with one direction being perpendicular to the other. Accordingly, the term “primary elongation direction” is used merely for convenience to define one direction of stretch. However, once one direction of stretch is defined as the “primary elongation direction”, the term “secondary elongation direction”, as used herein, refers to a direction that is perpendicular to the primary elongation direction. For example, for auxetic structures having polygon shaped cells with two or more substantially parallel opposing edges, such as those shown in FIGS. 1A and 1B (e.g., edges 11a and 11b in FIGS. 1A and 1B), the primary elongation direction may be considered to be a line that extends perpendicularly through the substantially parallel opposing edges (e.g., edges 11a and 11b) of the cells. Thus, in the auxetic structure of FIGS. 1A and 1B, the primary elongation direction may be defined by arrows 12. However, as noted above the primary elongation direction may alternatively be defined to be the perpendicular direction defined by arrows 13. In either case, the secondary elongation direction is the direction perpendicular to the primary elongation direction.

Auxetic Arrangement Including Auxetic Layer Disposed on Base Layer

In at least one embodiment, an auxetic arrangement 14 includes an auxetic structure 10 mounted on a flexible, resilient substrate. The auxetic structure 10 is an open framework capable of supporting the substrate and directing the substrate's expansion under a load. Accordingly, the auxetic structure, though flexible, may be more stiff than the substrate (i.e., the segments forming the auxetic structure 10 possess a higher elastic modulus than the substrate). The substrate, moreover, is generally more elastic than the auxetic structure in order to return the structure to its original state upon removal of the tensile strain.

With reference now to FIGS. 2A-2C, in at least one exemplary embodiment, an article of apparel 16 includes an auxetic arrangement 14 incorporated into at least one panel, such as a garment panel 18, or other portion with of the article of apparel. The auxetic arrangement 14 is comprised of a first or auxetic layer 20 coupled to a second or resilient layer 22 (the second layer 22 is shown under the first layer 20 in FIG. 2A). The second layer 22 may also be referred to as a “substrate layer” or a “base layer.”

The auxetic layer 20 includes the auxetic structure 10. Specifically, the auxetic layer 20 (and thus, the auxetic structure 10) is a plurality of segments 24 arranged to provide a repeating pattern or array of cells 26, each cell possessing a reentrant shape. Specifically, each cell 26 is defined by a set of interconnected structural members 24a, 24b, 24c, 24d, 24e, 24f, with an aperture or void 28 formed in the center of the cell 26. The void 28 exposes the second layer 22 to which the first layer 20 is coupled. Accordingly, the auxetic layer 20 is a mesh framework defined by segments 24 and voids 28.

In at least one embodiment, the auxetic layer 20 is unitary structure, with each cell 26 sharing segments 24 with adjacent cells. The cells 26 form an array of reentrant shapes, including a plurality of rows and columns of shapes defined by the voids 28. In the embodiment of FIG. 2A, the reentrant shapes are bow-tie shapes (or auxetic hexagon shapes, similar to the shapes shown in FIGS. 1A and 1B). However, it will be recognized by those of ordinary skill in the art that the cells 26 of the auxetic structure may include differently shaped segments or other structural members and differently shaped voids. FIGS. 3A-3B show two exemplary alternative auxetic structures. In FIG. 3A, the cells 26 of the auxetic layer 20 have a twisted triangular or triangular vortex shape, and the interconnected structural members are curved segments. In FIG. 3B, the cells 26 are oval shaped, and the interconnected structural members are rectangular or square structures.

In at least one embodiment, the segments 24 possess uniform dimensions. With reference again to the exemplary embodiment of FIGS. 2A and 2B, in an embodiment, the segments 24 forming the cells 26 (i.e., the cell structural members 24a-24f) are not necessarily uniform in shape and thickness. In particular, as shown in FIG. 2B, segment 24a is slightly bowed or convex along its length while segment 24b is substantially straight along its length. Segment 24a has a width, w, of between 1 mm and 5 mm, and particularly 3 mm. Segment 24b has a width, x, between 0.5 mm and 4 mm, and particularly 2 mm. While the segments 24 may vary somewhat in size and shape, the voids 28 are substantially uniform in size and shape. In the embodiment of FIG. 2B, the cell voids 28 have a height, y, between 6 and 12 mm, and particularly about 9.3 mm. The cell voids 28 have a width, z, between 6 and 12 mm, and particularly about 8.8 mm. Although not illustrated in FIG. 2B, the cross-sectional thickness of each segment 24 may be between 0.5 mm and 5 mm, and more specifically in some embodiments, between 1 mm and 2 mm, and particularly about 1.5 mm.

The auxetic layer 20 may be formed of any materials suitable for its described purpose. In an embodiment, the segments 24 are formed of any of various different resilient materials. In at least one exemplary embodiment, the segments 24 are comprised of a polymer such as ethylene-vinyl acetate (EVA), a thermoplastic such as nylon, or a thermoplastic elastomer such as polyurethane. Each of these materials possesses elastomeric qualities of softness and flexibility.

In another exemplary embodiment, the segments 24 are comprised of foam, such as a thermoplastic polyurethane (TPU) foam or an EVA foam, each of which is resilient and provides a cushioning effect when compressed. While EVA and TPU foam are disclosed herein as exemplary embodiments of the auxetic layer 20, it will be recognized by those of ordinary skill in the art that the auxetic layer 20 may alternatively be comprised of any of various other materials. For example, in other alternative embodiments, the auxetic layer may be comprised of polypropylene, polyethylene, XRD foam (e.g., the foam manufactured by the Rogers Corporation under the name PORON®), or any of various other polymer materials exhibiting sufficient flexibility and elastomeric qualities. In a further embodiment, the foam forming the auxetic layer is auxetic foam.

The segments 24 of the auxetic layer 20 may be formed in any of various methods. By way of example, the auxetic layer 20 is formed via a molding process such as compression molding or injection molding. By way of further example, the auxetic layer is formed via an additive manufacturing process such as selective laser sintering (SLS). In SLS, lasers (e.g., CO₂lasers) fuse successive layers of powdered material to form a three dimensional structure. Once formed, the auxetic layer 20 coupled (e.g., attached or mounted) to the base layer 22. Specifically, the auxetic layer 20 may be connected to the base layer 22 using any of various connection methods (examples of which are described in further detail below).

In at least one embodiment, the auxetic layer 20 is printed directly on to the base layer 22 using any of various printing methods, as will be recognized by those of ordinary skill in the art. Alternatively, the auxetic layer 20 may first be printed on a transfer sheet, and then a heat transfer method may be used to transfer the auxetic layer to the base layer 22.

As mentioned above, in at least one exemplary embodiment, the void 28 of each cell 26 in the auxetic layer 20 exposes the second layer 22 through the auxetic layer. In an alternative embodiment, the void 28 is filled with material such as an elastic material (e.g., a hot melt or other thermoplastic material) that partially or substantially fills the void 28 at the interior portion of the cell between the outer walls (i.e., the segments 24). The elastic material differs from the material forming the segments 24 of the auxetic layer. Filling the void with elastic material increases the resiliency of the auxetic structure. In contrast, a void 28 without material results in a more expansive auxetic structure 10 (compared to a filled void).

In order to design the auxetic layer 20 with desirable qualities, a number of design considerations must be balanced. These design considerations include, for example, the proximity of negative space (i.e., the proximity of the voids 28 associated with each cell 26), the cell size, the stroke distance (i.e., the distance a cell expands between a retracted position and a fully extended position), the mass, elasticity and strength of the material used for the cell walls. These design considerations must be carefully balanced to produce an auxetic structure with the desired qualities. For example, for a given material, if the voids in each cell are too large, the auxetic structure may be undesirably weak and flimsy. For the same material, if the voids in each cell are too small, the auxetic structure may be undesirably rigid and resistant to expansion. In at least one embodiment, it is desirable for the auxetic layer 20 to be more dominant than the base layer 22 such that application of a stress to the auxetic arrangement 14 will result in the more submissive base layer 22 conforming to any changes in the more dominant auxetic layer 20. Accordingly, in such embodiment, the cell walls must be designed such that the resulting auxetic layer 20 will be more dominant than the material of the base layer 22.

The base layer 22 is a flexible, resilient layer operable to permit the expansion of the auxetic layer 20 when tension is applied to the arrangement 14. Typically, the base layer 22 is an inner layer facing and/or contacting the wearer of the apparel. In an embodiment, the base layer 22 comprises a resilient material having selected stretch capabilities, e.g., four-way or two-way stretch capabilities. A material with “four way” stretch capabilities stretches in a first direction and a second, directly-opposing direction, as well as in a third direction that is perpendicular to the first direction and a fourth direction that is directly opposite the third direction. In other words, a sheet of four-way stretch material stretches in both crosswise and lengthwise. A material with “two way” stretch capabilities, in contrast, stretches to some substantial degree in the first direction and the second, directly opposing direction, but will not stretch in the third and fourth directions, or will only stretch to some limited degree in the third and fourth directions relative to the first and second directions (i.e., the fabric will stretch substantially less in the third and fourth directions than in the first direction and second directions). In other words, a sheet of two-way stretch material stretches either crosswise or lengthwise.

By way of example, the base layer 22 is formed of a four-way stretch fabric such as elastane fabric or other compression material including elastomeric fibers. By way of further example, the base layer 22 is comprised of the compression material incorporated into garments and accessories sold by Under Armour, Inc. as HEATGEAR or COLDGEAR compression fabric. In other embodiments, the base layer 22 is comprised of an elastic fabric having limited stretch properties, such as a two-way stretch fabric.

Selection of the base layer 22 relative to the auxetic layer 20 permits the control of the base layer stretch pattern and/or the auxetic layer stretch pattern (discussed in greater detail below).

It should be understood that, while the base layer 22 has been described as being formed of a stretch fabric, in other embodiments, the base layer may be comprised of other resilient materials, including any of various elastomers such as thermoplastic polyurethane (TPU), nylon, or silicone (e.g., a plastic sheet formed of resilient plastic). Furthermore, when the base layer is comprised of an elastomer, the base layer 22 may be integrally formed with the auxetic layer 20 to provide a continuous sheet of material that is seamless and without constituent parts, with the generally solid base layer on one side of the material and the auxetic structure on the opposite side of the material.

The auxetic layer 20 is coupled (e.g., mounted, attached, or fixed) to the base layer 22. By way of example, the auxetic layer 20 is an elastomer sheet bonded or otherwise directly connected to a stretch fabric base layer 22 such that the two layers 20 and 22 function as a unitary structure. To this end, the auxetic layer 20 may be connected to the base layer 22 via adhesives, molding, welding, sintering, stitching or any of various other means. In an embodiment, the auxetic layer 20 is brought into contact with the base layer 22 and then heat is applied to place the material forming the auxetic layer in a semi-liquid (partially melted) state such that material of the auxetic layer in contact with the base layer infiltrates the base layer fabric. Alternatively, the auxetic layer is applied in a molten or semi-molten state. In either application, once cooled, the auxetic layer 20 is securely fixed (permanently connected) to the fibers of the base layer 22 such that any movement of the base layer is transferred to the auxetic layer, and vice versa.

This structure including the auxetic layer 20 and the base layer 22—has been found to provide improved contouring properties around a three-dimension object compared to a structure including only the base layer. For example, when incorporated into an article of apparel 16 (e.g., a compression garment), the apparel easily and smoothly conforms to the various shapes and curvatures present on the body. The auxetic arrangement 14 is capable of double curvature forming synclastic and/or anticlastic forms when stretched. Double curvatures are prevalent along the human form. Accordingly, the auxetic arrangement 14 will follow the curvatures of the body with little to no wrinkling or folding visible to the wearer. Without being bound to theory, it is believed that the auxetic layer 20 cooperates with the base layer 22 to expand along two axes while tightly conforming to the surface of the wearer (e.g., to the wearer's foot, arm, leg, head, etc.).

With various configurations of the auxetic arrangement, then, it is possible to control the overall stretch/expansion pattern of the auxetic arrangement 14 by combining the individual properties of the auxetic layer 20 and the base layer 22. By way of example, it is possible to provide a non-auxetic layer with auxetic properties. In an embodiment, the base layer 22 is four-way stretch material that, by itself, is not auxetic (i.e., it exhibits a positive Poisson's ratio under load). Accordingly, when the base layer is separated from the auxetic layer and tension is applied across the base layer material, the base layer material contracts in the direction perpendicular to the applied tension. Superimposing the auxetic layer 20 over the base layer 22, however, provides a framework sufficient to drive the expansion pattern of the base layer. As a result, the base layer 22 in the combined structure (i.e., in the arrangement 14) will now follow the expansion pattern of the auxetic structure 10, expanding not only along the axis of the applied tensile strain, but also along the axis perpendicular to the axis of the applied tensile strain. The resiliency of the base layer 22, moreover, optimizes the contouring ability of the entire arrangement 14 since it tightly conforms to the surface of the wearer. Furthermore, the base layer 22, being resilient, limits the expansion of the auxetic layer 20 to that necessary to conform to the object. That is, the base layer 22, while permitting expansion of the auxetic layer 20, will draw the layer back towards its normal/static position. Accordingly, over expansion of the auxetic layer 20 is avoided.

Additionally, it is possible to limit the auxetic properties of the auxetic structure by selecting an appropriate base layer 22. When forming apparel 16 (e.g., footwear), while expansion is desired, it is often desirable to limit the degree of expansion along one or more axes. By selecting a base layer 22 of two-way stretch material, it is possible to limit the expansion along a selected axis. Specifically, mounting an auxetic layer 20 onto a base layer 22 formed of two-way stretch material permits the expansion of the auxetic arrangement 14 along an axis parallel to the two-way stretch direction of the base layer 22, but limits expansion of the arrangement along an axis perpendicular to the two-way stretch direction of the base layer 22. Accordingly, application of a tension along the two-way stretch direction of the base layer 22 results in significant expansion of the auxetic arrangement 14 along the two-way stretch direction, but only limited or no expansion of the auxetic arrangement along the axis perpendicular to the two-way stretch direction. Application of a tension along the axis perpendicular to the two way stretch direction results in limited or no expansion of the auxetic arrangement in either direction. In this manner, an article of apparel may possess a customized stretch direction, including a plurality of auxetic arrangements selected and position to provide optimum stretch properties to the apparel.

Thus, in embodiments where the base layer 22 has two-way or four-way stretch properties, the orientation of the base layer 22 relative to the auxetic layer 20 may have an effect on the overall stretch properties of the auxetic structure. For example, consider a panel 18 with a base layer 22 having two-way stretch properties configured such that the two way stretch direction of the base layer 22 is aligned with a stretch direction of the auxetic layer 20 (e.g., the two-way stretch direction of the base layer 22 is aligned with the arrows 12 shown on the auxetic structure 10 in the embodiment of FIG. 1B). The Poisson's ratio exhibited by this panel 18 may tend to be closer to zero, or “near zero”, than would be exhibited by a panel 18 including a base layer 22 with four-way stretch properties. In particular, because the base layer 22 limits stretch in the perpendicular direction (e.g., in the direction of arrows 13 in FIG. 1B), the stretch of the panel 18 will be limited in this perpendicular direction, thus keeping the Poisson's ratio for the panel closer to zero.

Finally, the combined structure including the auxetic layer 20 attached to the base layer 22 forms a more supportive structure than either layer alone. That is, the auxetic layer 20 described above provides an open framework that functions as a support structure for the article of apparel 16. For example, when used to form an upper in an article of footwear, the combined structure may be generally self-supporting. In other embodiments, the auxetic arrangement 14 possesses greater structure than the base layer 22 alone.

Additional Embodiments of Auxetic Layer Disposed on Base Layer

FIG. 2D shows a cross-sectional view of the auxetic layer 20 and base layer 22 according to another exemplary embodiment. In FIG. 2D, a foam layer 34 is provided between and couples the auxetic layer 20 to the base layer 22. The auxetic layer 20 and the base layer 22 may be coupled to the foam layer 34 using any of various means, including adhesives, molding, welding, sintering or any of various other means as will be recognized by those of ordinary skill in the art. The foam layer 34 is substantially the same shape and size as the auxetic layer and includes numerous segments and voids. The foam layer 34 may be comprised of any of various types of foam, such as a TPU foam, EVA foam, XRD foam (such as PORON® foam manufactured by Rogers Corporation). However, it will be recognized that the foam may be comprised of any of various materials, including other foam polymers. Because the foam layer 34 has the same structure as the auxetic layer 20, the foam layer 34 is configured to expand and contract with the auxetic layer, and does not provide substantial resistance to such expansion and contraction of the auxetic layer 20. However, the soft foam provides additional padding to the arrangement, with additional impact forces to the auxetic layer being absorbed by the foam layer 34. The foam layer 34 may be the same cross-sectional thickness as the segments 24 or a different thickness. In general, the cross-sectional thickness of the foam layer 34 is between 0.5 mm and 5 mm, and more specifically in some embodiments, between 1 mm and 2 mm, and particularly about 1.5 mm.

FIG. 2E shows a cross-sectional view of the auxetic layer 20 and base layer 22 according to another exemplary embodiment. In FIG. 2E, a foam layer 36 is provided between and couples the auxetic layer 20 to the base layer 22. The auxetic layer 20 and the base layer 22 may be coupled to the foam layer 36 using any of various means, including adhesives, molding, welding, sintering or any of various other means as will be recognized by those of ordinary skill in the art. The foam layer 36 is continuous and extends across the entire surface of the base layer 22 provided under the auxetic layer 20. Accordingly, the foam layer 36 may be referred to herein as a solid foam layer 36. The foam layer 36 may be comprised of any of various types of foam, such as a PU foam. However, it will be recognized that the foam may be comprised of any of various resilient materials, including other foam polymers. Because the foam layer 36 is resilient and elastic, the foam layer 36 will allow some expansion and contraction of the auxetic layer 20. However, because the foam layer 36 is continuous under the auxetic layer 20, the foam layer 36 provides some resistance to expansion and contraction of the auxetic layer 20. The resilient nature of the foam layer 36 also urges the auxetic layer 20 back to its static shape once a stretching force is removed from the auxetic layer 20. Again, the soft foam provided by the foam layer 36 provides additional padding to the arrangement, with additional impact forces to the auxetic layer being absorbed by the foam layer 36.

FIG. 2F shows a cross-sectional view of the auxetic layer 20 and base layer 22 according to yet another exemplary embodiment. In FIG. 2F, the article of apparel 16 includes an auxetic layer 20 sandwiched between an inner elastic layer (i.e., base layer 22) and an outer elastic layer 32. The outer elastic layer 32 may be comprised of the same or different material as the base layer 22, as described above, such as a four way stretch material. In this embodiment, the auxetic layer 20 is obscured from view, since the auxetic layer 20 is covered on both sides by layers of fabric on the inner elastic layer 22 and outer elastic layer 32. The outer elastic layer 32 provides additional resistance to expansion and contraction of the auxetic layer 20 over that provided when only a single elastic layer is provided as the base layer 22. Additionally, the outer elastic layer 32 provides additional resiliency to the arrangement, and urges the auxetic layer 20 back to its static shape once a stretching force is removed from the auxetic layer 20.

FIG. 2G shows a cross-sectional view of the auxetic layer 20 and base layer 22 according to another exemplary embodiment. In FIG. 2G, the article of apparel 16 includes an auxetic layer 20 sandwiched between an inner elastic layer (i.e., base layer 22) and an outer elastic layer 32, similar to that shown in FIG. 2F. However, in the embodiment of FIG. 2G, the outer elastic layer 32 is connected directly to the inner base layer 22 in the voids 28 of the auxetic layer 20. The connection between the outer elastic layer 32 and the inner base layer 22 may be accomplished in any of various ways as will be recognized by those of ordinary skill in the art, including the use of adhesives, molding, welding, sintering or any of various other means.

FIG. 2H shows a cross-sectional view of the auxetic layer 20 and base layer 22 according to another exemplary embodiment. The embodiment of FIG. 2H is similar to that of FIG. 2C, but in FIG. 2H, two layers of the auxetic layer 20 and base layer 22 are provided. In this embodiment, the segments 24 of the first auxetic layer are directly aligned with the segments of the second auxetic layer.

FIG. 2I shows a cross-sectional view of the auxetic layer 20 and base layer 22 according to yet another exemplary embodiment. The exemplary embodiment of FIG. 2I is similar to that of FIG. 2E, but in the exemplary embodiment of FIG. 2I, the solid foam layer 36 extends partially into the voids 28 of the auxetic layer 20.

FIG. 2J shows a cross-sectional view of the auxetic layer 20 and base layer 22 according to another exemplary embodiment. The exemplary embodiment of FIG. 2J is similar to that of FIG. 2I, but in the exemplary embodiment of FIG. 2I, the solid foam layer 36 extends completely through the voids 28 of the auxetic layer 20. As a result, the outer surface of the arrangement is substantially smooth to the touch of a human, as the outer surface of the foam layer 36 is substantially coplanar with the outer surface of the segments 24.

While various exemplary embodiments of the auxetic arrangement 14 have been shown in the embodiments of FIGS. 2C-2J, it will be appreciated that features from these various embodiments may be easily incorporated into other embodiments. For example, the elastic outer layer 32 of FIG. 2F may be easily added to an embodiment with an intermediate foam layer 34 or 36 between the auxetic layer 20 and the base layer 22, such as that shown in FIG. 2D or 2E. As another example, a two layer arrangement such as that shown in FIG. 2H may be prepared using the auxetic arrangement with a foam layer 34 or 36. Furthermore, the auxetic arrangement 14 described herein may be incorporated into any of various items of apparel, including garments, footwear, headwear, body pads, accessories, bags, and other items. Because the auxetic arrangement 14 easily conforms to various shapes and curvatures, the material provides a clean, neat appearance. Moreover, the stretching ability of the auxetic material provides for an extremely close fit for differently shaped wearers within a given size range.

Auxetic Structure on Skull Cap

With reference now to FIGS. 4A-4C, in at least one exemplary embodiment, the auxetic arrangement 14 described herein may be incorporated into skull caps 40 commonly worn under a football helmet. The skull cap 40 is used to provide additional protection for the wearer's head as well as allowing a tight fitting football helmet to more easily slip over the head. The auxetic arrangement 14 may be provided in various forms and in various locations on the cap 40. For example, the auxetic arrangement may include the elastic base layer 22 and the auxetic layer 20, as described above, incorporated into the crown or a middle region of the cap 40. The combination of the elastic base layer 22 in combination with the auxetic layer 20 having a negative Poisson's ratio allows the skull cap to closely fit a large number of different head sizes.

Additionally, protection can be provided to the wearer by providing an arrangement including the auxetic layer 20 and a shock absorbing foam material disposed on the base layer 22. The auxetic layer 20, in combination with the shock absorbing foam material, provides additional padding to protect the head from impacts commonly experienced during training or competition.

In the exemplary embodiment of FIGS. 4A-4C, the auxetic layer 20 is positioned adjacent to at least one compression layers, such as base layer 22. Also, the auxetic arrangement 14 may be provided over the entire skull cap 40, or only over a portion of the skull cap. For example, the auxetic arrangement 14 may form the crown 44 of the cap. Alternatively or in addition, the auxetic arrangement may forma middle area 42 of the cap 40, between an upper crown portion 44 and a lower edge 46 of the cap 40.

Footwear with Auxetic Structure

With reference now to FIGS. 5A-8C, in an embodiment, the auxetic arrangement 14 is incorporated into a shoe. Traditionally, shoe uppers are patterned and cut in two-dimensional panels, and these two-dimensional panels are stitched together to form a general three-dimensional shape. With these traditional shoe uppers, the generic shape of the upper is often ill-fitting in specific areas that are difficult to form such as heel, ankle, arch, toes and instep. Accordingly, the auxetic arrangement 14 disclosed herein may be advantageously used to form various portions of shoes because the auxetic arrangement 14 is configured to smoothly fit multiple curvatures on the wearer without the need for numerous seams or cuts in the material. The auxetic arrangement 14 may be used to form a complete shoe upper or limited portions of the shoe upper, including the heel, ankle, arch, toes and instep.

FIGS. 5A-5D illustrate one exemplary embodiment of the auxetic arrangement 14 used to form a fully auxetic shoe upper 50 with customized fit. As shown in FIGS. 5A-5D, the auxetic arrangement 14 may be cut into two panels having predetermined shapes, the panels contoured into the shape of a foot, and then joined along a medial seam 52 and a lateral seam 53 (see FIGS. 5B and 5C) to form the shoe upper 50 with opening 54 to receive the foot. The auxetic arrangement 14 described above, including the auxetic layer 20 in combination with the elastic base layer 22, is easily manipulated to form the multiple curved surfaces required for the shoe upper 50. As shown in the figures, it is possible to form the complete shoe upper 50 from only two pieces of the auxetic arrangement without wrinkling or folding of the material. These two pieces on the shoe upper 50 cover the entire foot, including the heel 56, midfoot 58 and toe regions 59. Although the embodiment of FIGS. 5A-5D shows a two-piece construction, in at least one alternative embodiment, a shoe upper with a one-piece construction may be formed using the auxetic arrangement 14 described herein. Once the shoe upper 50 is formed, it may be joined to a sole member 55, as shown in FIGS. 5A and 5B. Because of the auxetic arrangement 14, the shoe upper 50 has an elastic, expandable nature, allowing the shoe upper to provide a comfortable yet secure fit to various foot sizes and shapes.

FIGS. 6A and 6B show the shoe upper 50 of the article of footwear of FIGS. 5A-5D during an athletic activity, such as walking or running, where the foot of the wearer bends and flexes during the activity. As shown, the auxetic arrangement 14 allows the shoe upper 50 to continue to adhere closely (i.e., to contour) to the surface of the wearer's foot even as the foot flexes during athletic activity, with only limited bending or creasing of the auxetic arrangement 14.

FIGS. 7A-8C show various exemplary alternative embodiments in which the auxetic arrangement 14 is used to form only a portion of the shoe upper 50. In FIGS. 7A-7B, the auxetic material forms the heel 56 and midfoot portions 58 of the shoe upper, but does not extend to the forefoot portions or toes. In this embodiment, a hot melt is included in the inner portion of the auxetic cells, as discussed above, causing the auxetic material to be more resilient and offer additional support. Additionally, as shown in FIG. 7B, two seams 72, 74 are provided in the heel portion 56 of the shoe, allowing the auxetic cells 26 to be positioned in a preferred orientation on the heel and both sides of the midfoot portion. This preferred orientation configures the shoe to anticipate forces that may act upon the shoe and associated directions where expansion or contraction of the panel with the auxetic arrangement 14 is most likely to be needed. FIG. 7C shows an alternative embodiment where the auxetic arrangement 14 is only provided on the midfoot portion 58 of the shoe, and does not extend back to the heel 56 or forward to the toe 59.

FIGS. 8A-8C show another exemplary embodiment of footwear including the auxetic arrangement 14 described above. In this exemplary embodiment, the auxetic arrangement 14 is provided on an upper ankle portion 62 of a high top cleat 60. The auxetic arrangement 14 extends completely around the ankle region without extending to the heel, midfoot, or toe region of the cleat 60. The auxetic arrangement 14 is not only provided on the side of the ankle portion 62, but is also included on the tongue. The auxetic arrangement 14 on the ankle portion 62 may be provided as a two-piece construction, with one piece provided on the tongue, and another piece provided on the remainder of the ankle portion 62. Accordingly, no seams are required in the ankle region other than where the auxetic arrangement 14 connects to the other portions of the upper 50. Because the auxetic arrangement 14 easily conforms to the curvatures of the wearer's ankle, the auxetic arrangement acts as an ankle wrap on the wearer's ankle when the laces of the cleat 60 are tightened. Again, depending on the desired fit and support level, the cells of the auxetic layer 20 may be filled with a resilient material or may be void of material.

Garments with Auxetic Structure

With reference to FIGS. 9A-9C, an exemplary embodiment of an article of apparel 16 is shown in the form of a shirt 80 including one or more panels formed the auxetic arrangement 14 described above. In the embodiment of FIGS. 9A-9B, the auxetic arrangement 14 extends over the entire surface of the shirt 80. However, in other alternative embodiment, the auxetic arrangement 14 may be provided on only certain areas of the shirt 80, such as the arms 81, the chest portion, the back portion, and/or the abdomen portion. As described previously, the auxetic layer 20 of the auxetic arrangement 14 may be formed from a molding process or may be formed by a printing process. If a printing process is used the auxetic layer 20 may be directly printed on the base layer 22, and the auxetic layer 20 will typically be much thinner than if the auxetic layer is a molded structure. For example, if the auxetic layer is printed, the thickness of the auxetic layer may be less than 1 mm.

FIG. 9C shows an alternative exemplary embodiment wherein the article of apparel 16 is an arm sleeve 82 that is separate from a shirt.

FIGS. 10A-10B show an alternative exemplary embodiment wherein the article of apparel 16 is a short 84. Likewise, FIG. 10C shows an alternative exemplary embodiment wherein the article of apparel 16 is a leg sleeve 86. Each of these embodiments of FIGS. 9C-10C is similar to the embodiment of FIGS. 9A-9B, but the auxetic arrangement 14 is simply provided on a different article of apparel 16.

While the foregoing description provides a few limited exemplary embodiments of the auxetic arrangement 14 and associated use in various items of apparel, it will be recognized that numerous other embodiments are possible and contemplated although such additional embodiments are not specifically mentioned herein. For example, the auxetic material disclosed herein may also be used in scarves, gloves, hats, socks, sports bras, jackets, outdoor and hunting clothing, undergarments, elbow and knee pads, braces, bands, and various other articles of apparel. Because the auxetic arrangement 14 easily conforms to various shapes and curvatures, the material provides a clean, neat appearance. Moreover, the stretching ability of the auxetic material provides for an extremely close fit for differently shaped wearers within a given size range.

As discussed above, the auxetic arrangement 14 may be provided on any of various articles of apparel 16. Additional examples of articles of apparel that may incorporate the auxetic arrangement 14 include protective pads 90 such as those shown in FIGS. 11A-11C, including the chest protector 92 of FIG. 11A, the shin guards 94 of FIG. 11B, or the protective girdle 96 of FIG. 11C.

Backpack with Auxetic Arrangement

In yet another exemplary embodiment, the auxetic arrangement 14 may be provided in association with a bag, such as backpack 98 of FIG. 12. The backpack 98 includes a bag portion 99 and two shoulder/carrying straps 100. The bag portion 99 of the backpack 98 further includes an elastic panel 97 incorporating the auxetic arrangement 14, which elastic panel 97 may also be a near auxetic arrangement in some embodiments, as discussed above. When the panel 97 is subjected to forces associated with carrying a load, the panel 97 including the auxetic arrangement 14 will expand in size (or, when near auxetic, maintain a nearly constant dimension in a direction that is perpendicular to the direction of the load applied to the panel 97). As shown in FIG. 12, the panel 97 is provided on a bag portion 99 of the backpack. Other exemplary uses for the auxetic arrangement 14 in association with a bag include the use of the auxetic arrangement 14 on one or more straps 100 for the bag, as explained in further detail below with reference to FIGS. 13A-14D.

With reference to FIGS. 13A-13B in one exemplary embodiment, the shoulder strap 100 for the bag includes a shoulder pad 102. The shoulder pad 102 is provided as part of the carrying strap 100 which is coupled to the bag portion 99 of the backpack 98 (e.g., see FIG. 12 showing the backpack 98). In this embodiment, the auxetic arrangement 14 is included on the shoulder pad 102 of the carrying strap 100. As shown in FIG. 13B, one or more ends 104 of the shoulder pad 102 are directly connected to the carrying strap 100 by stitching 105 or other fastening means (e.g., adhesives, welding, or other coupling methods). The carrying strap 100, in turn, may be coupled to a bag (e.g., see backpack 98 of FIG. 12, not shown in FIGS. 13A-13B) or any other carrying device or load.

As shown in FIG. 13A, when a load 106 is applied to the ends 104 of the shoulder pad 102, the auxetic arrangement 14 expands in the direction of the applied load 106 and also in a direction 108 that is perpendicular to the applied load. As a result, the auxetic arrangement 14 of the shoulder pad 102 provides an increased surface area configured to bear the weight of the load. The increased surface area provided by the shoulder pad 102 makes carrying the load more comfortable for the user, as the weight of the load is spread across a greater area on the user's shoulder.

With reference now to FIGS. 14A-14D, an alternative embodiment of a shoulder pad 102 and carrying strap 100 arrangement is shown. In this embodiment, the shoulder pad 102 is manufactured such that the auxetic arrangement 14 has the shape shown in FIG. 14A, including flared sides 110 and 112. As shown in FIG. 14B, the flared sides 110, 112 are folded under and connected together during manufacture of the shoulder pad 102, thus creating a two-layer shoulder pad. As a result, the longitudinal edges of the shoulder pad 102 are positioned along the dotted lines 114, 116 as shown in FIG. 14A. As shown in FIG. 14C, when a load 106 is applied to the ends 104 of the shoulder pad 102, the auxetic arrangement 14 expands in the direction of the applied load 106 and also in a direction 108 that is perpendicular to the applied load. As a result, the auxetic arrangement 14 of the shoulder pad 102 provides an increased surface area configured to bear the weight of the load. The increased surface area provided by the shoulder pad 102 makes carrying the load more comfortable for the user, as the weight of the load is spread across a greater area on the user's shoulder.

With reference now to FIGS. 15-18, a backpack 210 with an auxetic/near auxetic strap is disclosed. The backpack 210 includes a bag 220 and two carrying straps 240. Each carrying strap 240 is coupled to the bag 220 and includes an elastic portion (i.e., exhibits a relatively low modulus of elasticity such as 0.5 Pa or less) having a relatively low Poisson's ratio. As explained in further detail herein, the straps 240 are configured to engage the back, shoulder and chest of a human wearer and distribute the load of the backpack across the straps 240 such that the dynamic pressure experienced by the user is reduced in the back and shoulder regions.

The bag 220 of the backpack may be provided in a form that is similar to any of various conventional backpack bags. In the embodiment of FIGS. 15-18, the bag includes a main body or frame that is formed of one or more suitable materials and includes a front side 222, a rear side 224, a left side 226, a right side 228, a top side 230, and a bottom side 232. The front side 222 of the bag 220 faces the back of a user when the backpack 210 is worn. The rear side 224 of the bag 220 faces away from the back of the user when the backpack is worn. The left side 226 of the bag 220 is positioned on the left side of the user when the backpack 210 is worn, and the right side 228 is positioned horizontally opposite the left side 226 on the right side of the user when the backpack 210 is worn. Similarly, the top side 230 of the backpack 210 is positioned closest to the user's head when the backpack is worn, and the bottom side 232 is vertically opposite the top side 230, furthest from the user's head when the backpack is worn.

Together, the front, rear, left, right, top and bottom sides 222, 224, 226, 228, 230, 232 combine to form a plurality of cavities, pockets, compartments or enclosures of varying sizes within the backpack for storing items (e.g., books, water bottles, shoes or other articles of apparel, electronic devices such as laptops and smart phones, etc.). The sides of the backpack combine to define a generally elongated (e.g., rectangular) shape in which a longer or lengthwise dimension of the backpack extends between the top side 230 and bottom side 232 (and thus a widthwise dimension of the backpack extends between the left side 226 and the right side 228, and a thickness dimension of the backpack extends between the front side 222 and the rear side 224).

Each of the sides of the backpack 210 can be formed of one or more panels (e.g., each side can be formed comprising a single, separate panel or two or more panels or, alternatively, two or more sides can be formed from one or more of the same panels). In embodiments in which the sides of the backpack are formed with two or more panels, the panels can be connected or secured to each other via any suitable connection (e.g., via a sewn or knitted seam, via lamination or any other suitable connection). Two or more sides of the backpack can include one or more openings that define a pocket, compartment or enclosure between two or more panels of the side and/or between two or more sides. One or more zippers 234 are incorporated into the bag 220 in order to provide a closure/access opening for such compartments. A handle 236 (e.g., formed of a fabric panel) comprising a loop attached at each end to the top side 230 of the bag 220 is also provided to facilitate easy lifting of the backpack 210 when not being worn by the user.

The panels that form the sides of the backpack 210 can be constructed of any suitably lightweight, flexible, water proof or water repellant and/or tear resistant materials including textiles or fabrics that are formed with any one or more suitable types of polymer materials, where the fabrics can further be formed in any suitable manner (e.g., any combinations of polymer fibers, yarns and/or filaments that form a fabric panel via knitting, weaving, nonwoven formation, etc.). Any suitable polymer materials can be used to form the fabric panels including, without limitation, polyamides (e.g., nylon materials), polyurethanes, polyolefins (e.g., polyethylenes, polypropylenes, etc.), polyesters (e.g., polyethylene terephthalate), polyacrylamides, polylactic acids, polyvinyl alcohol, and any variety of copolymers or combinations thereof. In addition, any one or more panels can be formed at least partially of elastomeric materials to provide a certain degree of elasticity to the fabric panel (e.g., to provide 2-way or 4-way stretch to a portion of the panel), where some non-limiting examples of elastic or stretchable fabric materials suitable for forming the outer fabric layer are fabrics comprising one or more combinations of polyester-polyurethane copolymers referred to generally as elastane (e.g., Spandex or Lycra materials).

Each panel forming a side or portion of a side of the backpack can further include one or more layers of material. For example, a panel that defines a portion of one or more sides of the backpack can include two or more layers, including an interior surface layer (i.e., an inward or enclosure facing layer) and an exterior surface layer (i.e., a layer that defines a portion of an exterior side of the backpack). One or more intermediate layers can also be provided within a panel (i.e., between the interior and exterior surface layers) so as to provide certain features for the panel. For example, one or more intermediate layers can comprise a foam material (e.g., polyurethane foam) to enhance the cushioning of the panel along one or more sides of the backpack. One or more interior layers can also include a hard and rigid material (e.g., a hard plastic, metal or other suitable material) to enhance the rigidity of the panel at certain locations of the backpack where it may be desired to provide greater stiffness or enhanced structural support.

The carrying straps 240 (which may alternatively be referred to as “shoulder straps”) are coupled to the front side 222 of the backpack 210. Each carrying strap 240 is an elongated member aligned at or near a widthwise end of the front side 222 and extending in a lengthwise direction of the backpack (i.e., between the top side 230 and the bottom side 232). One end of each carrying strap 240 connects at a top location of the backpack at a portion of the bag 220 that is at or near the top side 230 and the front side 222. The other end of the carrying strap 240 connects at a bottom location of the backpack at a portion of the bag 220 that is at or near the bottom side 232 and the front side 222. Each carrying strap 240 is suitably dimensioned to allow a user to place an arm through the gap between the strap and the main body or frame of the backpack 210 so as to wear the backpack with the straps extending over the shoulders of the user and the front side 222 of the bag 220 aligned with and touching/engaging (or in close proximity with) the user's back. Thus, the shoulder straps 240 facilitate support of the backpack 210 by the shoulders of the user wearing the backpack.

As best illustrated in FIG. 17, each carrying strap 240 comprises a plurality of sections, including an upper broad strap portion 242, a lower broad strap portion 244, a slip lock buckle 246 and a bottom webbing strap portion 248. The upper broad strap portion 242 is arranged at the top of the strap 240 and fixedly secured to the bag 220 at an upper portion of the backpack front side 222. The upper broad strap portion 242 is also fixedly connected to the lower broad strap portion 244 (which upper and lower broad strap portions 242, 244 may be referred to collectively as the “broad strap” or “broad strap portion”). The lower broad strap portion 244 is arranged on the strap 240 between the upper broad strap portion 242 and the bottom webbing strap portion 248. The bottom webbing strap portion 248 is arranged at the bottom of the strap 240 and fixedly secured to the bag 220 at a lower portion of the backpack front side 222. The slip lock buckle 246 couples the lower broad strap portion to the bottom webbing strap portion 248.

The upper broad strap portion 242 is an elastic length of the strap 240 that is relatively wide and is configured to engage the shoulders of the wearer. A strip of lockout webbing 270 is provided along the length of the upper broad strap portion 242 and limits the amount of stretch/elongation of the upper broad strap portion 242, as explained in further detail below. The shoulder strap 240 may be considered to have a plurality of sections that correspond to body parts of the user when the backpack 210 is in use. Specifically, the upper broad strap portion 242 includes a back section 252, a shoulder section 254 and an armpit section 256. When the backpack 210 is in use, the back section 252 is configured to extend upward on the back of the user to the rear side of the shoulder; the shoulder section 254 is configured to wrap around the shoulder of the user from back to front; the armpit section 256 is configured to extend downwardly from the shoulder and to a position that is lateral from the sternum where the upper broad strap portion 242 is fixedly connected to the lower broad strap portion 244.

In at least some embodiments, the upper broad strap portion 242 is provided by a corrugated strap with elastic properties, such as that shown in FIG. 19. The corrugated strap includes an outer sheath 260 that encases a plurality of elastic strands that run generally lengthwise along the strap 240. The outer sheath 260 is illustrated in FIG. 19 and includes a plurality of parallel ridges 262 and furrows 264 that run widthwise across the strap 240 (i.e., transverse to the length direction of the strap 240). The ridges 262 are formed by loops of fabric and the furrows 264 are arranged between the ridges 262. The loops of fabric extend outwardly from a center axis/planar strip defined by the strap 240 (i.e., when the strap 240 is laid flat), turn 180°, and then return to the center axis/planar strip. The loops of fabric may all be tilted on one direction (i.e., arranged at an angle of less than 90° relative to the center axis) such that the ridges 262 lie somewhat flatly upon one another. The ridges 262 are interleaved (i.e., arranged alternately on opposite sides of the strap) such that the occurrence of a ridge 262 on one side of the strap is accompanied by a furrow 264 on the directly opposite side of the strap. The corrugated nature of the upper broad strap 242 provides for a cushioning effect on the shoulders of the wearer when the backpack is carried.

The material used to form the upper broad strap portion 242 includes multiple strands of different materials, including some relatively inelastic fibers used to form the sheath 260, and other highly elastic fibers encased within the sheath. The inelastic fibers may include any of various flexible and soft fibers as are commonly used to form backpack straps, such as nylon, polyester, polyethylene, polypropylene, acrylic, cotton, etc. The elastic materials may include any of various natural or synthetic rubber materials known to provide elasticity with excellent recovery properties, such as latex rubber, neoprene, etc. The material that provides the broad strap portion 242 is similar to that of a bungee cord wherein multiple elastic strands are encased in a woven or braided outer sheath comprised of strands of the inelastic material. In at least some embodiments, the elastic strands are at least partially interwoven with the inelastic strands in order to tie the elastic strands to the inelastic strands. For example, by weaving the elastic strands with the inelastic strands, the corrugated structure shown in FIG. 19 may be created.

The elastic properties of the upper broad strap portion 242 allow it to be stretched between a relaxed position (i.e., contracted or recovered position) and a stretched position (i.e., elongated or tensioned position). Advantageously, the corrugated elastic structure of the upper broad strap portion 242 results in a strap that has auxetic or near auxetic properties when moved from the relaxed position to the stretched position. The term “auxetic” as used herein refers to structures or materials that possess or exhibit a negative (below zero) Poisson's ratio at some point during stretch. The term “near auxetic,” moreover, is used herein to refer to a structure having a Poisson's ratio of approximately zero and, in particular, less than +0.15. Accordingly, when the strap 240 is subjected to a force in the length direction, the width of the strap at the upper broad strap portion 242 remains relatively constant, or even expands.

As noted previously, a strip of lockout webbing 270 is provided along the length of the upper broad strap portion 242 and limits the amount of stretch/elongation of the upper broad strap portion 242 when moved from the relaxed position to the stretched position. The lockout webbing 270 is comprised of a generally inelastic material, such as woven strands of nylon fibers. The lockout webbing 270 is sequentially connected to the upper broad strap portion 242 at a number of connection locations 272 that are equally spaced apart along the length of the upper broad strap portion 242. The lockout webbing 270 is fixedly connected to the upper broad strap portion 242 at each of the connection locations 272, but is free-floating (i.e., not connected to the broad strap portion 240) at all other locations along the length of the lockout webbing 270.

Each of the connection locations 272 are provided by connecting means that extend transversely across the width lockout webbing 270 (i.e., parallel to the ridges of the upper broad strap portion 242 and connect the lockout webbing to the upper broad strap portion 242. Any of various connection means may be used to couple the lockout webbing 270 to the upper broad strap portion 242 at the connection locations, including, for example, the use of stitching and/or adhesives. The connection locations 272 may be, for example, 1″-4″ apart along the length of the upper broad strap portion 242, and in some embodiments, between 2″ and 3″ apart. Each length of lockout webbing 270 extending between two connection locations 272, may be considered a different segment of the lockout webbing 270.

Loops 274 are formed in the lockout webbing 270 between the connection locations 272. In other words, each segment of the lockout webbing 270 is defined by a loop 274. The length of each loop 274 is greater than the distance between each of the connection locations 272. Therefore, as explained in further detail below, the loops 274 are loose and removed from the surface of the upper broad strap portion 242 when the upper broad strap portion is in the relaxed position, but the loops 274 are elongated and under tension such that they engage the surface of the upper broad strap portion 242 when the upper broad strap portion is stretched to a limit position.

With reference now to FIGS. 20 and 21, it will be recognized that the lockout webbing 270 limits the extent of stretch of the upper broad strap portion 242 of the strap 240. FIG. 20 shows a user holding the upper broad strap portion 242 in the relaxed position. In this position, the ridges 262 of the corrugated sheath 260 are spaced tightly together (i.e., the furrows 264 are narrow). Also in this relaxed position, the loops 274 of the lockout webbing 270 are loose and form U-shapes wherein the ends of each U-shape are connected to the upper broad strap portion 242 at connection locations 272, and the rest the U-shape is bunched and removed from the surface of the upper broad strap portion 242. FIG. 21 shows the user holding the upper broad strap portion 242 in the stretched position at lockout (which may be referred to herein as a “stretched lockout position”). In this position, the ridges 262 of the corrugated sheath 260 are spread further apart (i.e., the furrows 264 are wider). Also in this stretched lockout position, the lockout webbing 270 is fully extended and surface portions along the entire length of the lockout webbing 270 abut and engage surface portions of the upper broad strap portion 242. In other words, the upper broad strap portion 242 has been stretched such that the distance between each connection location 272 is equal to the length of each loop 274 of the lockout webbing 270. Because the lockout webbing 270 is non-elastic (i.e., “inelastic”), the upper broad strap portion 242 is not able to extend past this lockout position. Accordingly, it will be recognized that although the backpack 210 described herein is configured with an elastic strap 240, the lockout feature on the elastic strap prevents the strap (and particularly the upper broad strap portion 242) from extending to an extent that is unstable and comfortable for the user.

Returning now to FIGS. 15-18, the bottom of the upper broad strap portion 242 is fixedly connected to the top of the lower broad strap portion 244. The lower broad strap portion 244 is comprised of one or more panels formed of one or more layers of material that can be the same or similar materials as the layers forming panels for the main body of the backpack as described herein. For example, the panels defining the straps can be formed of one or more fabric materials including a plurality of layers with one or more intermediate foam layers provided between inner and outer fabric layers. The panels of the lower broad strap portion 244 are generally inelastic (i.e., exhibit a relatively high modulus of elasticity, such as 3.5 Pa or more) and not configured to stretch to any significant degree when under load. The width of the lower broad strap portion 244 is similar to that of the upper back strap portion, resulting in a continuous strap effect between the upper broad strap portion 242 and the lower broad strap portion 244. As best shown in FIG. 18, each lower broad strap portion 244 is slightly curved such that the lower broad strap portion 244 moves laterally outward from top to bottom.

The bottom of the lower broad strap portion 244 is fixedly coupled to a slip lock buckle 246. The slip lock buckle 246 is formed of a suitably hard/non-flexible material (i.e., a harder material in relation to the material(s) forming the lower broad strap portion 244) such as plastic or metal. The slip lock buckles 246 each include an upper portion that is secured to the lower broad strap portion 244 and a lower portion that receives the bottom webbing strap portion 248 (which may also be referred to herein as simply a “webbing strap”) in a slip lock arrangement as will be recognized in association with other adjustable straps in conventional backpacks.

An upper portion of the webbing strap 248 adjustably engages the slip lock buckle 246. The bottom end of the webbing strap 248 is fixedly connected to a lower portion of the bag 220 on the front side 222 of the backpack. The webbing strap 248 is comprised of a generally inelastic material, such as woven strands of nylon fibers. Because the upper portion of the webbing strap 248 adjustably engages the slip lock buckle 246, the effective length of the webbing strap 248 may be adjusted as desired by the user, thus making the overall length of the carrying strap 240 either longer or shorter to fit the size of the user.

In addition to the above, it will be recognized that sternum webbing 276 and a sternum clip 278 may also be provided on the straps 240. In particular, a length of sternum webbing 276 is coupled to one of the lower loops 274 of the lockout webbing 270 on each upper broad strap portion 242 of the straps 240. The sternum clip 278 is advantageously used to couple the sternum webbing 276 together and provide additional comport and load distribution for the user.

The multi-part shoulder strap 240 disclosed herein provides significant advantages over conventional shoulder straps. Particularly, the corrugated structure of the upper broad strap portion 242 with auxetic or near auxetic properties advantageously increases the surface area over which the straps 240 contact the body of the user, and limit the peak dynamic pressure experienced by the user at various body locations when carrying a loaded backpack. It has been determined that the percentage of static contact with the user is increased in the back section 252 and shoulder section 254 in embodiments of the strap wherein the upper broad strap portion 242 has a width between 2″ and 4″. In at least some embodiments (e.g., when the width of the upper broad strap portion is 2″), static contact with the user is also increased in the armpit section. In association with this, peak dynamic pressure experienced by the user is significantly reduced over the back section 252 and shoulder section 254 of the strap. As a result, the multi-part shoulder strap 240 results in a backpack 210 that is more comfortable for the user and reduces back and shoulder fatigue when the backpack is used over extended periods of time.

While one embodiment of the backpack is shown in association with FIGS. 15-21, it will be recognized that other embodiments are contemplated, including embodiments wherein the corrugated elastic structure used for the above-described upper broad strap portion 242 is incorporated into other portions of the backpack 210, such as the bag 220. For example, as shown in FIG. 22, the front side 222 of the bag 220 of the backpack 210 may include a split corrugated panel 280 that includes the same structure as the upper broad strap portion 242 described above. The split corrugated panel 280 includes a left side panel 282 and a right side panel 284 with a vertical spine 286 positioned between the left side panel 282 and the right side panel 284. Because the left side panel 282 and right side panel 284 are formed from the corrugated elastic material described above, they are configured to flex and allow additional space to be provided for in the interior of the bag 220 (i.e., the volume of the bag may be slightly enlarged along the panels 282 and 284 when the bag is stuffed with a load. At the same time, the vertical spine 286 may be comprised of a generally non-elastic material, similar to other portions of the bag 220, and thereby limits the amount of overall flex on the front side 222 of the bag 220.

FIG. 23 shows another embodiment of the backpack 210 wherein the corrugated elastic structure of the above-described upper broad strap portion 242 is incorporated into the bag 220. The embodiment of FIG. 23 is similar to that of FIG. 22, but the corrugated elastic structure is provided on a panel 288 that extends across the entire front side 222 of the bag 220. As such, the bag 220 may be significantly expanded when stuffed with a load.

In an embodiment, the strap, instead of being auxetic or near auxetic, is provided with a structure that resists compression or narrowing in a direction transverse or orthogonal to the direction of strain or load. By way of example, the strap may be configured to possess a lower Poisson ratio than a conventional strap construction. The Poisson's ratio of a structure depends on its geometrical arrangement and the way it deforms under the action of external force. Non-auxetic materials, when placed under load, contracts (narrows) in the direction transverse to the load or stretch axis. These materials tend to have a positive (greater than zero) Poisson's ratio. A textile with zero auxetic properties exhibits no change in the transverse direction, (neither contraction nor expansion) when the material is stretched in the longitudinal direction, possessing a Poisson ratio of approximately zero. Textiles that are auxetic expand in the direction transverse to the load direction (possessing a negative Poisson ratio). The value of Poisson's ratio depends on the direction of extension and amount of transverse deformation.

In textiles, the auxetic structure can be produced by knitting, nonwoven, and weaving process. Production of auxetic woven fabrics may be achieved by either incorporating auxetic yarns into a conventional weave design or by incorporating conventional yarns into an auxetic weave design. In forming the strap conventional yarns are incorporated into an auxetic weave design. By way of specific example, the woven fabric of the strap may be a combination of plain weave and float with an auxetic design configured such that, when the structure is pulled along the direction of the warp, the textile opens, expanding the fabric in the transverse direction. As noted above, a plurality of elastic cords forms the core of the fabric, extending along the warp direction.

With this configuration, the strap is configured with a synclastic curvature that better adapts to the complex curvatures of the body. By way of example, the transverse expansion property of the strap under load helps form double curvatures during bending and stretching. This property allows the straps to adapt to the changing contours of the human body during movement and/or to exhibit lower stress concentration compared to traditional textiles (i.e., textiles with higher Poisson ratios).

The foregoing detailed description of one or more exemplary embodiments of the articles of apparel including auxetic materials has been presented herein by way of example only and not limitation. It will be recognized that there are advantages to certain individual features and functions described herein that may be obtained without incorporating other features and functions described herein. Moreover, it will be recognized that various alternatives, modifications, variations, or improvements of the above-disclosed exemplary embodiments and other features and functions, or alternatives thereof, may be desirably combined into many other different embodiments, systems or applications. Presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the appended claims. Therefore, the spirit and scope of any appended claims should not be limited to the description of the exemplary embodiments contained herein.

	Number	Date	Country
Parent	17463423	Aug 2021	US
Child	18516477		US
Parent	15918629	Mar 2018	US
Child	17463423		US
Parent	14137250	Dec 2013	US
Child	15918629		US

	Number	Date	Country
Parent	18516477	Nov 2023	US
Child	18895033		US
Parent	13838827	Mar 2013	US
Child	14137250		US

ARTICLE OF APPAREL WITH COMFORT STRAP

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Abstract

Description

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CROSS-REFERENCE TO RELATED APPLICATIONS

Provisional Applications (1)

Continuations (3)

Continuation in Parts (2)