BACKPACK WITH ELASTIC STRAPS

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority from U.S. Provisional Ser. No. 63/698,409 , filed Sep. 24, 2024, the entire contents of which are incorporated herein by reference.

FIELD

The present disclosure relates to the field of bags, and particularly bags with straps configured to be carried by a human.

BACKGROUND

Backpacks are popular bags for transporting devices and are commonly used in school, business, and recreational settings. Backpacks are typically used to transport multiple items such as books, food, water, clothes, shoes and portable electronic devices. In view of the number of items a person may need to transport with them for any given scenario, a loaded backpack is often heavy and cumbersome, and may present a substantial burden to the human user when carried for a long period of time or for a significant distance. Therefore, it would be desirable to provide further features for a backpack to enhance its versatility, functionality, comfort and convenience. For example, it would be desirable to provide a backpack with features configured to evenly distribute the weight of a heavily loaded backpack across the user's back and shoulders, maintain the backpack straps in proper contact with the user, and reduce the dynamic pressure imparted to the user when carrying the backpack.

SUMMARY

A bag is disclosed herein in the form of a backpack. The backpack comprises a bag portion and at least one shoulder strap coupled to the bag portion. The least one shoulder strap includes an elastic upper broad strap portion connected to an inelastic lower broad strap portion. The upper broad strap portion defines a corrugated structure having a plurality of parallel ridges and furrows. The upper broad strap portion is also configured to stretch between a relaxed position and a stretched lockout position. A lockout webbing is coupled to the upper broad strap portion at a plurality of connection locations along the upper broad strap portion. Loops in the lockout webbing are formed between the connection locations when the upper broad strap portion is in the relaxed position. The lockout webbing is fully extended when the upper broad strap portion is in the stretched lockout position.

In at least one embodiment, the backpack comprises a bag and at least one shoulder strap coupled to the bag. The at least one shoulder strap includes an elastic broad strap portion configured to stretch between a relaxed position and a stretched lockout position, wherein the broad strap portion is auxetic or near auxetic. Lockout webbing is coupled to the broad strap portion at a plurality of connection locations along the broad strap portion. Loops in the lockout webbing are formed between the connection locations when the broad strap portion is in the relaxed position. The lockout webbing is fully extended when the upper broad strap portion is in the stretched lockout position.

In at least one embodiment, a bag includes a shoulder strap and a bag configured to retain a load. The at least one shoulder strap is coupled to the bag portion and includes an elastic broad strap portion configured to stretch between a relaxed position and a stretched lockout position. The broad strap portion is auxetic or near auxetic. Additionally, the broad strap portion defines a corrugated structure having a plurality of parallel ridges and furrows.

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 a backpack or other bag that provides one or more of these or other advantageous features as may be apparent to those reviewing this disclosure, the teachings disclosed herein extend to those embodiments which fall within the scope of the appended claims, regardless of whether they include or accomplish one or more of the advantages or features mentioned herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a front perspective view of a backpack with elastic straps and lockout webbing;

FIG. 2 shows a rear perspective view of the backpack of FIG. 1:

FIG. 3 shows a side view of the backpack of FIG. 1;

FIG. 4 shows a front view of the backpack of FIG. 1;

FIG. 5 shows an enlarged perspective view of an elastic strap of the backpack of FIG. 1 in isolation from the lockout webbing;

FIG. 6 shows a user holding an elastic strap of the backpack of FIG. 1 in a relaxed position;

FIG. 7 shows the user holding the elastic strap of FIG. 6 in a stretched position:

FIG. 8 shows a front view of an alternative embodiment of the backpack of FIG. 1 included a split corrugated forward panel; and

FIG. 9 shows a front view of another alternative embodiment of the backpack of FIG. 1 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 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.

It will be recognized that backpack disclosed herein may be placed in any number of orientations during times of use and non-use by a user. Accordingly, terms of orientation and position used herein in association with the backpack are defined with reference to a human user in an upright position. Therefore, the “front” (or forward portion) of the backpack, as used herein, references the straps that are configured to engage the front of the human user when worn on a human user. Similarly, the associated forward portion/panel of the bag portion of the backpack is the portion that is closest to the straps (even though the forward panel actually engages the back of the human user when the backpack is worn). Likewise, the “back” (or rearward portion) of the backpack references the rearward portion/panel of the bag portion of the backpack that faces rearward, away from the user, and does not engage the body of the user when the backpack is worn. The term “top” of the backpack references the portion that is closest to the human head when the backpack is worn, and the term “bottom” references the portion that is furthest removed from the human head when the backpack is worn. The term “vertical” references a direction that is generally perpendicular to level earth, and “horizontal” references a direction that his generally parallel to level earth. Similarly, the term “above” references a relative position where one component is vertically higher than another component, and “below” references a relative position where one component is vertically lower than another component.

With references now to FIGS. 1-4, a backpack 10 includes a bag 20 and two carrying straps 40. Each carrying strap 40 is coupled to the bag 20 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 40 are configured to engage the back, shoulder and chest of a human wearer and distribute the load of the backpack across the straps 40 such that the dynamic pressure experienced by the user is reduced in the back and shoulder regions.

The bag 20 of the backpack may be provided in a form that is similar to any of various conventional backpack bags. In the embodiment of FIGS. 1-4, the bag includes a main body or frame that is formed of one or more suitable materials and includes a front side 22, a rear side 24, a left side 26, a right side 28, a top side 30, and a bottom side 32. The front side 22 of the bag 20 faces the back of a user when the backpack 10 is worn. The rear side 24 of the bag 20 faces away from the back of the user when the backpack is worn. The left side 26 of the bag 20 is positioned on the left side of the user when the backpack 10 is worn, and the right side 28 is positioned horizontally opposite the left side 26 on the right side of the user when the backpack 10 is worn. Similarly, the top side 30 of the backpack 10 is positioned closest to the user's head when the backpack is worn, and the bottom side 32 is vertically opposite the top side 30, furthest from the user's head when the backpack is worn.

Together, the front, rear, left, right, top and bottom sides 22, 24, 26, 28, 30, 32 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.) and thereby retaining a load. 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 30 and bottom side 32 (and thus a widthwise dimension of the backpack extends between the left side 26 and the right side 28, and a thickness dimension of the backpack extends between the front side 22 and the rear side 24).

Each of the sides of the backpack 10 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 34 are incorporated into the bag 20 in order to provide a closure/access opening for such compartments. A handle 36 (e.g., formed of a fabric panel) comprising a loop attached at each end to the top side 30 of the bag 20 is also provided to facilitate easy lifting of the backpack 10 when not being worn by the user.

The panels that form the sides of the backpack 10 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 40 (which may alternatively be referred to as “shoulder straps”) are coupled to the front side 22 of the backpack 10. Each carrying strap 40 is an elongated member aligned at or near a widthwise end of the front side 22 and extending in a lengthwise direction of the backpack (i.e., between the top side 30 and the bottom side 32). One end of each carrying strap 40 connects at a top location of the backpack at a portion of the bag 20 that is at or near the top side 30 and the front side 22. The other end of the carrying strap 40 connects at a bottom location of the backpack at a portion of the bag 20 that is at or near the bottom side 32 and the front side 22. Each carrying strap 40 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 10 so as to wear the backpack with the straps extending over the shoulders of the user and the front side 22 of the bag 20 aligned with and touching/engaging (or in close proximity with) the user's back. Thus, the shoulder straps 40 facilitate support of the backpack 10 by the shoulders of the user wearing the backpack.

As best illustrated in FIG. 3, each carrying strap 40 comprises a plurality of sections, including an upper broad strap portion 42, a lower broad strap portion 44, a slip lock buckle 46 and a bottom webbing strap portion 48. The upper broad strap portion 42 is arranged at the top of the strap 40 and fixedly secured to the bag 20 at an upper portion of the backpack front side 22. The upper broad strap portion 42 is also fixedly connected to the lower broad strap portion 44 (which upper and lower broad strap portions 42, 44 may be referred to collectively as the “broad strap” or “broad strap portion”). The lower broad strap portion 44 is arranged on the strap 40 between the upper broad strap portion 42 and the bottom webbing strap portion 48. The bottom webbing strap portion 48 is arranged at the bottom of the strap 40 and fixedly secured to the bag 20 at a lower portion of the backpack front side 22. The slip lock buckle 46 couples the lower broad strap portion to the bottom webbing strap portion 48.

The upper broad strap portion 42 is an elastic length of the strap 40 that is relatively wide and is configured to engage the shoulders of the wearer. A strip of lockout webbing 70 is provided along the length of the upper broad strap portion 42 and limits the amount of stretch/elongation of the upper broad strap portion 42, as explained in further detail below. The shoulder strap 40 may be considered to have a plurality of sections that correspond to body parts of the user when the backpack 10 is in use. Specifically, the upper broad strap portion 42 includes a back section 52, a shoulder section 54 and an armpit section 56. When the backpack 10 is in use, the back section 52 is configured to extend upward on the back of the user to the rear side of the shoulder; the shoulder section 54 is configured to wrap around the shoulder of the user from back to front; the armpit section 56 is configured to extend downwardly from the shoulder and to a position that is lateral from the sternum where the upper broad strap portion 42 is fixedly connected to the lower broad strap portion 44.

In at least some embodiments, the upper broad strap portion 42 is provided by a corrugated strap with elastic properties, such as that shown in FIG. 5. The corrugated strap includes an outer sheath 60 that encases a plurality of elastic strands that run generally lengthwise along the strap 40. The outer sheath 60 is illustrated in FIG. 5 and includes a plurality of parallel ridges 62 and furrows 64 that run widthwise across the strap 40 (i.e., transverse to the length direction of the strap 40). The ridges 62 are formed by loops of fabric and the furrows 64 are arranged between the ridges 62. The loops of fabric extend outwardly from a center axis/planar strip defined by the strap 40 (i.e., when the strap 40 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 62 lie somewhat flatly upon one another. The ridges 62 are interleaved (i.e., arranged alternately on opposite sides of the strap) such that the occurrence of a ridge 62 on one side of the strap is accompanied by a furrow 64 on the directly opposite side of the strap. The corrugated nature of the upper broad strap 42 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 42 includes multiple strands of different materials, including some relatively inelastic fibers used to form the sheath 60, 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 42 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. 5 may be created.

The elastic properties of the upper broad strap portion 42 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). In an embodiment, the upper broad strap portion 42 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 upper broad strap portion may be configured to possess a lower Poisson's 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 upper broad strap portion 42, conventional yarns are incorporated into an auxetic weave design. By way of specific example, the woven fabric of the upper strap portion 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. A plurality of elastic cords forms the core of the fabric, extending along the warp direction.

With this configuration, the upper broad strap portion 42 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 auxetic materials 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).

Advantageously, the corrugated elastic structure of the upper broad strap portion 42 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 40 is subjected to a force in the length direction, the width of the strap at the upper broad strap portion 42 remains relatively constant, or even expands.

As noted previously, a strip of lockout webbing 70 is provided along the length of the upper broad strap portion 42 and limits the amount of stretch/elongation of the upper broad strap portion 42 when moved from the relaxed position to the stretched position. The lockout webbing 70 is comprised of a generally inelastic material, such as woven strands of nylon fibers. The lockout webbing 70 is sequentially connected to the upper broad strap portion 42 at a number of connection locations 72 that are equally spaced apart along the length of the upper broad strap portion 42. The lockout webbing 70 is fixedly connected to the upper broad strap portion 42 at each of the connection locations 72, but is free-floating (i.e., not connected to the upper broad strap portion 42) at all other locations along the length of the lockout webbing 70. Accordingly, the lockout webbing 70 is loose from and moveable relative to the broad strap portion 42 at the distinct short segments of the lockout webbing 70 defined between the connection locations 72.

Each of the connection locations 72 are provided by connecting means that extend in a linear manner transversely across the width lockout webbing 70 (i.e., parallel to the ridges of the upper broad strap portion 42 and connect the lockout webbing to the upper broad strap portion 42. Any of various connection means may be used to couple the lockout webbing 70 to the upper broad strap portion 42 at the connection locations, including, for example, the use of stitching and/or adhesives. The connection locations 72 may be, for example, 1″-4″ apart along the length of the upper broad strap portion 42, and in some embodiments, between 2″ and 3″ apart. Each length of lockout webbing 70 extending between two connection locations 72, may be considered a different “segment” of the lockout webbing 70.

Loops 74 are formed in the lockout webbing 70 between the connection locations 72. In other words, each segment of the lockout webbing is defined by a loop 74. The length of each loop 74 is greater than the distance between each of the connection locations 72. Therefore, as explained in further detail below, the loops 74 are loose and removed from the surface of the upper broad strap portion 42 when the upper broad strap portion is in the relaxed position, but the loops 74 are elongated and under tension such that they engage the surface of the upper broad strap portion 42 when the upper broad strap portion is stretched to a limit position.

With reference now to FIGS. 6 and 7, it will be recognized that the lockout webbing 70 limits the extent of stretch of the upper broad strap portion 42 of the strap 40. FIG. 6 shows a user holding the upper broad strap portion 42 in the relaxed position. In this position, the ridges 62 of the corrugated sheath 60 are spaced tightly together (i.e., the furrows 64 are narrow). Also in this relaxed position, the loops 74 of the lockout webbing 70 are loose and form U-shapes wherein the ends of each U-shape are connected to the upper broad strap portion 42 at connection locations 72, and the rest the U-shape is bunched and removed from the surface of the upper broad strap portion 42. FIG. 7 shows the user holding the upper broad strap portion 42 in the stretched position at lockout (which may be referred to herein as a “stretched lockout position”). In this position, the ridges 62 of the corrugated sheath 60 are spread further apart (i.e., the furrows 64 are wider). Also in this stretched lockout position, the lockout webbing 70 is fully extended and surface portions along the entire length of the lockout webbing 70 abut and engage surface portions of the upper broad strap portion 42. In other words, the upper broad strap portion 42 has been stretched such that the distance between each connection location 72 is equal to the length of each loop 74 of the lockout webbing 70. Because the lockout webbing 70 is non-elastic (i.e., “inelastic”), the upper broad strap portion 42 is not able to extend past this lockout position. Accordingly, it will be recognized that although the backpack 10 described herein is configured with an elastic strap 40, the lockout feature on the elastic strap prevents the strap (and particularly the upper broad strap portion 42) from extending to an extent that is unstable and comfortable for the user.

Returning now to FIGS. 1-4, the bottom of the upper broad strap portion 42 is fixedly connected to the top of the lower broad strap portion 44. The lower broad strap portion 44 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 44 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 44 is similar to that of the upper back strap portion, resulting in a continuous strap effect between the upper broad strap portion 42 and the lower broad strap portion 44. As best shown in FIG. 4, each lower broad strap portion 44 is slightly curved such that the lower broad strap portion 44 moves laterally outward from top to bottom.

The bottom of the lower broad strap portion 44 is fixedly coupled to a slip lock buckle 46. The slip lock buckle 46 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 44) such as plastic or metal. The slip lock buckles 46 each include an upper portion that is secured to the lower broad strap portion 44 and a lower portion that receives the bottom webbing strap portion 48 (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 48 adjustably engages the slip lock buckle 46. The bottom end of the webbing strap 48 is fixedly connected to a lower portion of the bag 20 on the front side 22 of the backpack. The webbing strap 48 is comprised of a generally inelastic material, such as woven strands of nylon fibers. Because the upper portion of the webbing strap 48 adjustably engages the slip lock buckle 46, the effective length of the webbing strap 48 may be adjusted as desired by the user, thus making the overall length of the carrying strap 40 either longer or shorter to fit the size of the user.

In addition to the above, it will be recognized that sternum webbing 76 and a sternum clip 78 may also be provided on the straps 40. In particular, a length of sternum webbing 76 is coupled to one of the lower loops 74 of the lockout webbing 70 on each upper broad strap portion 42 of the straps 40. The sternum clip 78 is advantageously used to couple the sternum webbing 76 together and provide additional comport and load distribution for the user.

The multi-part shoulder strap 40 disclosed herein provides significant advantages over conventional shoulder straps. Particularly, the corrugated structure of the upper broad strap portion 42 with auxetic or near auxetic properties advantageously increases the surface area over which the straps 40 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 52 and shoulder section 54 in embodiments of the strap wherein the upper broad strap portion 42 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 52 and shoulder section 54 of the strap. As a result, the multi-part shoulder strap 40 results in a backpack 10 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. 1-7, 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 42 is incorporated into other portions of the backpack 10, such as the bag 20. For example, as shown in FIG. 8, the front side 22 of the bag 20 of the backpack 10 may include a split corrugated panel 80 that includes the same structure as the upper broad strap portion 42 described above. The split corrugated panel 80 includes a left side panel 82 and a right side panel 84 with a vertical spine 86 positioned between the left side panel 82 and the right side panel 84. Because the left side panel 82 and right side panel 84 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 20 (i.e., the volume of the bag may be slightly enlarged along the panels 82 and 84 when the bag is stuffed with a load. At the same time, the vertical spine 86 may be comprised of a generally non-elastic material, similar to other portions of the bag 20, and thereby limits the amount of overall flex on the front side 22 of the bag 20.

FIG. 9 shows another embodiment of the backpack 10 wherein the corrugated elastic structure of the above-described upper broad strap portion 42 is incorporated into the bag 20. The embodiment of FIG. 9 is similar to that of FIG. 8, but the corrugated elastic structure is provided on a panel 88 that extends across the entire front side 22 of the bag 20. As such, the bag 20 may be significantly expanded when stuffed with a load.

Although the various embodiments have been provided herein, it will be appreciated by those of skill in the art that other implementations and adaptations are possible. For example, the corrugated elastic structure described herein may be incorporated into yet other parts of the backpack, including other parts of the straps and the bag in addition to those parts described above. Furthermore, aspects of the various embodiments described herein may be combined or substituted with aspects from other features to arrive at different embodiments from those described herein. Thus, it will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various 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 following claims.