BACKGROUND

[0001] Participants in recreational or athletic activities may require hydration while participating in the activity. The participants may transport liquid on their persons, such as in liquid-carrying garments, for convenience and to minimize downtime. Regulatory bodies of certain activities may require that participants in the activities carry liquid on their person. The regulatory bodies may mandate that the garments that the participants use to carry liquid meet certain requirements. For example, the liquid-carrying garments may also be required to hold additional equipment, such as a walking stick, raingear, a blanket, a light, or a bottle. As another example, the liquid-carrying garments may be required to have certain dimensions. While essential to the activities, the liquid-carrying garments may be uncomfortable or burdensome to wear.

SUMMARY

[0002] A participant in a recreational or athletic activity may transport liquid using a hydration pack. The hydration pack may comprise a main body formed from a warp-knit fabric. The main body may have a tubular shape or another three-dimensional shape. The shape may define a cavity. The cavity may be configured to store liquid. The cavity may have a compression gradient configured to cause liquid to move towards a top of the cavity or to meet a hose.

[0003] A first portion of the main body may be folded to be disposed adjacent a second portion of the main body. The first portion may be coupled to the second portion. The first portion coupled to the second portion may define a multilayer structure. The hydration pack may comprise an aperture configured to allow access to the liquid stored in the cavity. The hydration pack may comprise a plurality of sections. A section may comprise a material with a higher modulus of elasticity than another section.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] The following drawings illustrate generally, by way of example, but not by way of limitation, various examples discussed in the present disclosure. In the drawings: [0005] FIG. 1 shows an example hydration pack pattern.

[0006] FIG. 2 shows an example body of a hydration pack.

[0007] FIG. 3 shows an example body of a hydration pack.

[0008] FIG. 4 shows an example body of a hydration pack.

[0009] FIG. 5 shows an example method of making a hydration pack.

DETAILED DESCRIPTION

[0010] FIG. 1 shows an example pattern for a hydration pack 100. The hydration pack 100 may comprise a backpack, a vest, a shirt, or another garment or equipment configured to hold liquid. The hydration pack 100 may be configured to be worn directly against the skin of a user of the hydration pack 100. The hydration pack 100 may be configured to be worn over another garment worn by the user. The hydration pack 100 may be configured to be worn on the abdomen, the back, or the hips of a user, for example.

[0011] The hydration pack 100 may comprise a main body 101. The main body 101 may comprise a plurality of sections. The main body 101 may comprise an exterior bladder pocket section 102. The exterior bladder pocket section 102 may comprise two layers. The two layers may be formed from a knitted material. The knitted material may comprise a warp- knitted material. The knitted material may comprise a polyester, another polymer, or a blend thereof, for example. The knitted material may comprise a plurality of looped structures. The looped structures may be arranged in rows. At least a portion of looped structures in one row may be interlocked with at least a portion of looped structures of another row, such as an adjacent row. The knitted material may comprise a moisture management yarn. The exterior bladder pocket section 102 may comprise a mesh material. The mesh material may be coupled to the two layers of knit material, such as sewn to the knit material.

[0012] The exterior bladder pocket section 102 may comprise a cavity between the two layers. The cavity may be configured to hold a bladder. The exterior bladder pocket section 102 may comprise one or more apertures 103. The apertures 103 may be configured to enable access to the cavity. The apertures 103 may comprise ducts from the cavity to the space external to the hydration pack 100. The apertures 103 may be configured for a hose, tube, and/or nozzle coupled to the bladder to exit or enter the exterior bladder pocket section 102. The hose, tube, and/or nozzle may be coupled to the bladder. The hose, tube, and/or nozzle may be configured to draw or deliver liquid from the bladder to a user. The exterior bladder pocket section 102 may comprise a closed top 112. The top 112 may be sewn shut. The closed top 112 may be disposed between the apertures 103. The closed top 112 may be configured to secure the bladder within the exterior bladder pocket section 102.

[0013] The exterior bladder pocket section 102 may comprise a pulley that creates a compression gradient in the exterior bladder pocket section 102 or in the cavity within the exterior bladder pocket section 102. The pulley may be configured to tighten the cavity as a quantity of liquid in the bladder decreases. The pulley may be configured to loosen the cavity as the quantity of liquid in the bladder increases. The cavity may comprise a material configured to compress the liquid in the cavity as the quantity of liquid decreases. For example, the material may comprise a high-powered lycra. The material may be configured to create a compression gradient. For example, the material may compress the liquid more near a bottom of the cavity than near a top of the cavity. The areas of the cavity with greater compression may comprise more of the material, such as a greater density or concentration of the material.

[0014] The exterior bladder pocket section 102 may have a shape that is configured to fit or conform to a body of a user of the hydration pack 100. For example, the exterior bladder pocket section 102 may have a scooped shape at the top configured for a neck of the user. The exterior bladder pocket section may have scooped shapes at the side to make holes for arms of the user. The sides may be closed. For example, the sides may be sewn. The exterior bladder pocket section 102 may be configured to be worn on a back of a user when the hydration pack 100 is in normal use.

[0015] The main body 101 may comprise one or more waist sections 104. The waist sections 104 may comprise a material having a modulus of elasticity that is greater than the material of other sections of the main body 101. Modulus of elasticity may be measured by a standardized test, such as ASTM C469M, ASTM E2769, ASTM C469, or ASTM El 11. The waist sections 104 may comprise two layers. The waist sections 104 may be configured to be worn on a waist or under the arms of a user when the hydration pack 100 is in normal use.

[0016] The main body 101 may comprise one or more side sections 105a, 105b. The side sections 105a, 105b may comprise two layers. The side sections 105a, 105b may comprise side apertures (not shown). The side sections 105a, 105b may each have multiple side apertures, such as double slit openings. The side sections 105a, 105b may comprise pockets 107. The pockets 107 may comprise closing mechanisms, such as zippers or pulleys. The side sections 105a, 105b may comprise different materials or the same materials. One side section 105a may comprise a material having a greater modulus of elasticity than a material of the other side section 105b. At least one of the side sections 105a, 105b may have a functional aperture 120. The side sections 105a, 105b may comprise tabs 108. The tabs 108 may be coupled to the side sections 105a, 105b such as by knitting or welding (e.g., ultrasonic welding). The tabs 108 may be configured to be joined, such as to secure the hydration pack 100 on the body of the user. The tabs 108 may comprise a closing mechanism, such as clips or velcro.

[0017] The main body 101 may comprise a lower section 109. The lower section 109 may comprise two layers. The lower section 109 may comprise a cavity, such as within a pocket. The cavity may be configured to store equipment, such as a pole. The cavity may comprise a non-mesh material. The lower section 109 may be configured to be worn on a waist or on hips of a user when the hydration pack 100 is in normal use.

[0018] The main body 101 may comprise wing sections 110. The wing sections 110 may each comprise two layers. The wing sections 110 may comprise a first layer that is configured to be in contact with the body of a user when the hydration pack 100 is in normal use. The wing sections 110 may each comprise a second layer that is configured to be external to the body of the user or to face opposite the body of the user when they hydration pack 100 is in normal use. The first layer and the second layer may comprise same or different material. As an example, the first layer may comprise a non-mesh material and the second layer may comprise a mesh material. The wing sections 110 may each comprise a cavity, such as for a pocket. A portion of each of the wing sections 110 may be open, such as to provide a pathway to the cavity.

[0019] The main body 101 may comprise a unitary piece of knitted fabric. For example, the exterior bladder pocket section 102, the waist sections 104, the side sections 105a, 105b, the lower section 109, and/or the wing sections 110 may comprise a unitary piece of knitted fabric. The exterior bladder pocket section 102, the waist sections 104, the side sections 105a, 105b, the lower section 109, and/or the wing sections 110 may comprise pieces of material coupled to the unitary piece of knitted fabric. The main body 101 may comprise a first portion folded to be disposed adjacent a second portion of the main body 101. For example, the first portion may comprise an interior side of the hydration pack 100 and the second portion may comprise an exterior side of the hydration pack 100. The first portion folded to be disposed adjacent the second portion may define a multilayer structure of the main body 101. As an example, the main body 101 may comprise two, four, six, eight, or more layers. Two or more of the layers may form a cavity. The cavity may comprise the cavity of the exterior bladder pocket section 102 configured to hold a bladder and/or any of the pockets. The cavity may be partitioned to form distinct cavities or pockets, such as with one or more seams. The seams may be formed by sewing, gluing, and/or welding, as examples.

[0020] The main body 101 may comprise a coupling mechanism configured to couple the first portion to the second portion. The coupling mechanism may comprise sewing, gluing, or ultrasonic welding of the first portion and the second portion, for example. The coupling of the first portion to the second portion may form a seam. The seam may be disposed at one of various locations on the hydration pack 100, depending on the configuration of the first portion folded on the second portion. To illustrate, the seam may be located along an edge. The seam may account for a portion of a weight of the hydration pack 100. The seam may be minimized to minimize the weight of the hydration pack 100. Minimizing the seam may also reduce the labor required to manufacture the hydration pack 100. For example, a length of the seam may be minimized to minimize the weight of the hydration pack 100. The seam may be minimized by the unitary piece of material comprising at least a portion of the main body 101. The seam may be minimized by the first portion of the main body 101 being folded to be disposed adjacent the second portion of the main body 101. The folding of the first portion over the second portion may eliminate the need to couple different pieces of fabric, wherein the coupling of the different pieces of fabric may form a seam.

[0021] The hydration pack 100 may comprise one or more accessory components. The accessory components may be coupled to the main body 101. The accessory components may comprise closing mechanisms, such as to close a cavity or pocket of the main body 101.

Examples of closing mechanisms include pulleys, zippers, snaps, hooks, and velcro. The accessory components may comprise mechanisms for securing equipment to the hydration pack 100, such as straps or hooks.

[0022] FIG. 2a shows an example hydration pack body 201. The body 201 may comprise the main body 101 or a portion of the main body 101 of the hydration pack 100 in FIG. 1. FIG. 2a may show the body 201 having a simplified pattern to illustrate the concept of a making and/or folding the main body 101 or a portion of the main body 101. The main body 101 may comprise the body 201, but with a different pattern, such as a pattern similar to the pattern shown in FIG. 1.

[0023] The body 201 may be formed from a knitted material. The knitted material may comprise a warp-knitted material. The knitted material may comprise a polyester, another polymer, or a blend thereof, for example. The material may be selected based on a desired property of the hydration pack 100. Examples of properties include weight, waterproofness, wind resistance, reflectivity, breathability, flexibility, strength, and appearance. The knitted material may comprise a plurality of interlocked loops. The knitted material may comprise a moisture management yarn. The yarn may comprise a first layer of yarn configured to draw moisture and pass the moisture to a second layer. The second layer maybe configured to release the moisture to the surrounding environment.

[0024] The body 201 may comprise a unitary piece of knitted fabric. The body 201 may comprise a tubular shape or another three-dimensional shape defining a cavity 202. The three-dimensional shape may comprise a tubular or cylindrical shape with sides or ends that are shaped based on a pattern of the hydration pack. For example, FIG. 3 shows a three-dimensional shape that is based on a shirt-like pattern of a hydration pack. FIG. 4 shows a three-dimensional shape that is based on a vest-like pattern of a hydration pack. The body 201 may comprise a first open end 203a. The body 201 may comprise a second open end 203b opposite the first open end 203a. The cavity 202 may comprise an area between the first open end 203a and the second open end 203b.

[0025] The body 201 may flattened. The flattened body 201 may form a first layer overlapping a second layer of the body 201. The flattened body 201 may comprise a first portion 204a. The flattened body 201 may comprise a second portion 204b. The first portion 204a may be folded to be disposed adjacent the second portion 204b. For example, the first portion 204a may be folded over a y-axis. The y-axis may be located at a center of the flattened body 201.

For example, as depicted in FIG. 2a, the y-axis may pass through a center of the flattened body 201 and run along a length or width of the flattened body 201. Alternatively, the y-axis may be off-center relative the flattened body 201. The y-axis may run along a diagonal line or another line relative to the length and the width of the flattened body 201.

[0026] FIG. 2b shows the flattened body 201 with the first portion 204a folded over the y-axis to be disposed adjacent the second portion 204b. The first portion 204a folded to be disposed adjacent the second portion 204b may define a multilayer structure of the body 201.

For example, FIG. 2b depicts the body 201 as comprising a four-layer structure. The cavity 202 may be disposed between one or more of the layers. For example, in FIG. 2b, the cavity 202 is depicted as disposed between adjacent layers 205a and 205b. The cavity 202 is depicted as disposed between adjacent layers 205c and 205d.

[0027] After the first portion 204a is folded to be disposed adjacent the second portion 204b, the first portion 204a and the second portion 204b may be coupled. As examples, the first portion 204a may be sewn, glued, or ultrasonically welded to the second portion 204b. A portion of the first portion 204 and a portion of the second portion 204b may be coupled. The first portion 204a coupled to the second portion 204b may form a seam.

[0028] At least a portion of the first open end 203 a or the second open end 203b may be closed. For example, the first open end 203a or the second open end 203b may be sewn, glued, or ultrasonically welded closed. At least a portion of the first open end 203 a or the second open end 203b may be left open to form an aperture. Liquid stored in the cavity 202 may be accessed via the aperture.

[0029] The aperture may be formed in the body 201. For example, a hole may be formed in the body 201 that exposes at least a portion of the cavity 202. One or more storage pockets may be coupled to the body 201. For example, the pockets may be formed by coupling fabric to the body 201. Straps may be coupled to the body 201. Zippers, bungees, or pulleys may be coupled to the body 201. Additional fabric may be coupled to the body 201.

[0030] The tubular shape of the body 201 should not be construed as limited to a particular design. The design may vary depending on a type of hydration pack that the body 201 forms. To illustrate, FIG. 3a shows a body 301 for a hydration pack comprising a vest or backpack. The body 301 may comprise a three-dimensional shape defining a cavity 302. The body 301 may comprise a first open end 303a. The body 301 may comprise a second open end 303b opposite the first open end 303a. The cavity 302 may comprise an area between the first open end 303a and the second open end 303b.

[0031] The body 301 may flattened. The flattened body 301 may form a first layer overlapping a second layer of the body 301. The flattened body 301 may comprise a first portion 304a. The flattened body 301 may comprise a second portion 304b. The first portion 304a may be folded to be disposed adjacent the second portion 304b. For example, the first portion 304a may be folded over a z-axis.

[0032] FIG. 3b shows the flattened body 301 with the first portion 304a folded over the z-axis to be disposed adjacent the second portion 304b. The first portion 304a folded to be disposed adjacent the second portion 304b may define a multilayer structure of the body 301.

For example, FIG. 3b depicts the body 301 as comprising a four-layer structure. The cavity 302 may be disposed between one or more of the layers. For example, in FIG. 3b, the cavity 302 is depicted as disposed between adjacent layers 305a and 305b. The cavity 302 is depicted as disposed between adjacent layers 305c and 305d.

[0033] After the first portion 304a is folded to be disposed adjacent the second portion 304b, the first portion 304a and the second portion 304b may be coupled. As examples, the first portion 304a may be sewn, glued, or ultrasonically welded to the second portion 304b. A portion of the first portion 304 and a portion of the second portion 304b may be coupled. The first portion 304a coupled to the second portion 304b may form a seam.

[0034] At least a portion of the first open end 303 a or the second open end 303b may be closed. For example, the first open end 303a or the second open end 303b may be sewn, glued, or ultrasonically welded closed. At least a portion of the first open end 303 a or the second open end 303b may be left open to form an aperture. Liquid stored in the cavity 302 may be accessed via the aperture.

[0035] As an additional example, FIG. 4a shows a body 401 for a hydration pack comprising a vest or a backpack. The body 401 may comprise a three-dimensional shape defining a cavity 402. The body 401 may comprise a first open end 403a. The body 401 may comprise a second open end 403b opposite the first open end 403a. The cavity 402 may comprise an area between the first open end 403a and the second open end 403b. The body 401 may comprise a first closed end 404a. The body 401 may comprise a second closed end 404b opposite the first closed end 404a.

[0036] The body 401 may flattened. The flattened body 401 may form a first layer overlapping a second layer of the body 401. The flattened body 401 may comprise a first portion at the open end 403a. The flattened body 301 may comprise a second portion at the open end 403b. The first portion 403a may be folded to be disposed adjacent the second portion 403b.

For example, the first portion 403a may be folded over an x-axis. [0037] FIG. 4b shows the flattened body 401 with the first portion 403a folded over the x-axis to be disposed adjacent the second portion 403b. The first portion 403a folded to be disposed adjacent the second portion 403b may define a multilayer structure of the body 401.

For example, FIG. 4b depicts the body 401 as comprising a four-layer structure. The cavity 402 may be disposed between one or more of the layers. For example, in FIG. 4b, the cavity 402 is depicted as disposed between adjacent layers 405a and 405b. The cavity 402 is depicted as disposed between adjacent layers 405c and 405d.

[0038] After the first portion 403a is folded to be disposed adjacent the second portion 403b, the first portion 403a and the second portion 403b may be coupled. As examples, the first portion 403a may be sewn, glued, or ultrasonically welded to the second portion 403b. A portion of the first portion 403 a and a portion of the second portion 403b may be coupled. The first portion 403a coupled to the second portion 403b may form a seam.

[0039] At least a portion of the first open end 403 a or the second open end 403b may be closed. For example, the first open end 403a or the second open end 403b may be sewn, glued, or ultrasonically welded closed. At least a portion of the first open end 403 a or the second open end 403b may be left open to form an aperture. Liquid stored in the cavity 302 may be accessed via the aperture.

[0040] The present disclosure comprises at least the following aspects:

[0041] Aspect 1. A hydration pack comprising: a body having at least two layers defining a cavity between the at least two layers, wherein the body is formed from a warp-knit material, wherein the cavity is configured to hold a liquid storage bladder; and an aperture disposed through the body, thereby allowing access to the cavity.

[0042] Aspect 2. The hydration pack of aspect 1, wherein a first portion of the hydration pack comprises a first material and a second portion of the hydration pack comprises a second material different than the first material; and wherein the first material has a higher modulus of elasticity than the second material.

[0043] Aspect 3. The hydration pack of any one of aspects 1-2, wherein at least a portion of the hydration pack comprises a mesh material.

[0044] Aspect 4. The hydration pack of any one of aspects 1-3, further comprising a portion comprising a single layer of material. [0045] Aspect 5. The hydration pack of any one of aspects 1-4, further comprising a plurality of pockets.

[0046] Aspect 6. The hydration pack of any one of aspects 1-5, wherein the body comprises a material configured to cause a compression gradient in the cavity.

[0047] Aspect 7. A hydration pack comprising: a main body having a three- dimensional shape defining at least one cavity, wherein a first portion of the main body is folded to be disposed adjacent a second portion of the main body thereby defining a multilayer structure, and wherein the main body is formed from a knitted material; a coupling mechanism configured to couple the first portion to the second portion; and an aperture disposed through the main body, thereby allowing access to the at least one cavity.

[0048] Aspect 8. The hydration pack of aspect 7, wherein the at least one cavity is configured to hold liquid.

[0049] Aspect 9. The hydration pack of any one of aspects 7-8, wherein the knitted material comprises a plurality of rows of looped structures, wherein the plurality of rows comprises at least a first row and a second row adjacent to the first row, wherein at least a subset of loop structures of the first row are interlocked with at least one loop structure of the second row, and wherein the first layer and the second layer are joined by at least the subset of the loop structures of the first row and the at least one loop structure of the second row.

[0050] Aspect 10. The hydration pack of any one of aspects 7-9, wherein the hydration pack is configured to be worn on an abdomen of a user.

[0051] Aspect 11. The hydration pack of any one of aspects 7-10, wherein the hydration pack is configured to be worn on a back of a user.

[0052] Aspect 12. The hydration pack of any one of aspects 7-11, wherein the hydration pack comprises at least one of a vest, a backpack, or a fanny pack.

[0053] Aspect 13. The hydration pack of any one of aspects 7-12, wherein the multilayer structure comprises a four-layer structure.

[0054] Aspect 14. The hydration pack of any one of aspects 7-13, wherein the multilayer structure comprises structure with at least two layers.

[0055] Aspect 15. The hydration pack of any one of aspects 7-14, wherein the knitted material comprises a polyester. [0056] Aspect 16. The hydration pack of any one of aspects 7-15, wherein a first portion of the hydration pack comprises a first material and a second portion of the hydration pack comprises a second material different than the first material; and wherein the first material has a higher modulus of elasticity than the second material.

[0057] Aspect 17. The hydration pack of any one of aspects 7-16, wherein at least a portion of the hydration pack comprises a mesh material.

[0058] Aspect 18. The hydration pack of any one of aspects 7-17, further comprising a portion comprising a single layer of material.

[0059] Aspect 19. The hydration pack of any one of aspects 7-18, further comprising a plurality of pockets.

[0060] Aspect 20. The hydration pack of any one of aspects 7-19, wherein the main body comprises a material configured to cause a compression gradient in the cavity.

[0061] Aspect 21. The hydration pack of any one of aspects 7-20, wherein the hydration pack further comprises a plurality of pockets.

[0062] Aspect 22. The hydration pack of aspect 21, wherein at least a portion of the plurality of pockets are formed from the knitted material.

[0063] Aspect 23. The hydration pack of aspect 21, wherein at least a portion of the plurality of pockets are coupled to the main body.

[0064] Aspect 24. A method of making a hydration pack comprising: knitting a main body having a three-dimensional shape defining at least one cavity; folding a first portion of the main body to be disposed adjacent a second portion of the main body thereby defining a multilayer structure; coupling the first portion to the second portion; and closing a portion of an end of the main body to define an aperture allowing access to the at least one cavity.

[0065] Aspect 25. The method of aspect 24, wherein the at least one cavity is configured to hold liquid.

[0066] Aspect 26. The method of any one of aspects 24-25, wherein the coupling the first portion to the second portion comprises at least one of sewing or ultrasonically welding the first portion to the second portion.

[0067] Aspect 27. The method of any one of aspects 24-26, wherein the multilayer structure comprises a four-layer structure. [0068] Aspect 28. The method of any one of aspects 24-27, wherein the multilayer structure comprises structure with at least two layers.

[0069] Aspect 29. The method of any one of aspects 24-28, wherein the knitting the main body comprises warp knitting the main body.

[0070] Aspect 30. The method of any one of aspects 24-29, wherein the main body comprises a polyester.

[0071] Aspect 31. The method of any one of aspects 24-30, wherein a first portion of the hydration pack comprises a first material and a second portion of the hydration pack comprises a second material different than the first material; and wherein the first material has a higher modulus of elasticity than the second material.

[0072] Aspect 32. The method of any one of aspects 24-31, wherein at least a portion of the hydration pack comprises a mesh material.

[0073] Aspect 33. The method of any one of aspects 24-32, further comprising coupling a single layer of material to the main body.

[0074] Aspect 34. The method of any one of aspects 24-33, further comprising partitioning the cavity.

[0075] Aspect 35. The method of any one of aspects 24-34, wherein the partitioning the cavity comprises at least one of sewing, gluing, or welding a portion of the main body.

[0076] Aspect 36. The method of any one of aspects 24-35, wherein the partitioning the cavity comprises forming two or more separated cavities.

[0077] Aspect 37. The method of any one of aspects 24-36, wherein the hydration pack comprises a plurality of pockets.

[0078] Aspect 38. The method of any one of aspects 24-37, further comprising coupling a material to the main body configured to cause a compression gradient in the cavity.

[0079] Aspect 39. An apparatus for making a hydration pack comprising: means for knitting a main body having a three-dimensional shape defining at least one cavity; means for folding a first portion of the main body to be disposed adjacent a second portion of the main body thereby defining a multilayer structure; and means for coupling the first portion to the second portion; wherein the hydration pack has an aperture through the main body, thereby allowing access to the at least one cavity. [0080] Aspect 40. The apparatus of aspect 39, wherein the at least one cavity is configured to hold liquid.

[0081] Aspect 41. The apparatus of any one of aspects 39-40, wherein the means for coupling the first portion to the second portion comprises at least one of sewing or ultrasonically welding the first portion to the second portion.

[0082] Aspect 42. The apparatus of any one of aspects 39-41, wherein the multilayer structure comprises a four-layer structure.

[0083] Aspect 43. The apparatus of any one of aspects 39-42, wherein the multilayer structure comprises structure with at least two layers.

[0084] Aspect 44. The apparatus of any one of aspects 39-43, wherein the means for knitting the main body comprise a warp knitting component.

[0085] Aspect 45. The apparatus of any one of aspects 39-44, wherein the first portion and the second portion each have a length, wherein a portion of the first portion coupled to a portion of the second portion has a length less than or equal to twenty-five percent of the length of the first portion and the second portion.

[0086] Aspect 46. The apparatus of any one of aspects 39-45, wherein the main body comprises polyester.

[0087] Aspect 47. The apparatus of any one of aspects 39-46, wherein a first portion of the hydration pack comprises a first material and a second portion of the hydration pack comprises a second material different than the first material; and wherein the first material has a higher modulus of elasticity than the second material.

[0088] Aspect 48. The apparatus of any one of aspects 39-47, wherein at least a portion of the hydration pack comprises a mesh material.

[0089] Aspect 49. The apparatus of any one of aspects 39-48, wherein the hydration pack comprises a portion having a single layer.

[0090] Aspect 50. The apparatus of any one of aspects 39-49, wherein the hydration pack comprises a plurality of pockets.

[0091] Aspect 51. The apparatus of any one of aspects 39-50, wherein the hydration pack comprises a material configured to cause a compression gradient in the cavity.

[0092] Aspect 52. A machine configured to perform a process comprising: knitting a main body having a three-dimensional shape defining at least one cavity; folding a first portion of the main body to be disposed adjacent a second portion of the main body thereby defining a multilayer structure; and coupling the first portion to the second portion; wherein the hydration pack has an aperture through the main body, thereby allowing access to the at least one cavity.

[0093] Aspect 53. The machine of aspect 52, wherein the at least one cavity is configured to hold liquid.

[0094] Aspect 54. The machine of any one of aspects 52-53, wherein the coupling the first portion to the second portion comprises at least one of sewing or ultrasonically welding the first portion to the second portion.

[0095] Aspect 55. The machine of any one of aspects 52-54, wherein the multilayer structure comprises a four-layer structure.

[0096] Aspect 56. The machine of any one of aspects 52-55, wherein the multilayer structure comprises structure with at least two layers.

[0097] Aspect 57. The machine of any one of aspects 52-56, wherein the knitting the main body comprises warp knitting the main body.

[0098] Aspect 58. The machine of any one of aspects 52-57, wherein the knitting the main body comprises weft knitting the main body.

[0099] Aspect 59. The machine of any one of aspects 52-58, wherein the main body comprises a polyester.

[00100] Aspect 60. The machine of any one of aspects 52-59, wherein the machine comprises a warp knitting machine.

[00101] Aspect 61. The machine of any one of aspects 52-60, wherein the machine comprises a flat-bed knitting machine.

[00102] Aspect 62. A product formed by: knitting a main body having a three- dimensional shape defining at least one cavity; folding a first portion of the main body to be disposed adjacent a second portion of the main body thereby defining a multilayer structure; and coupling the first portion to the second portion; wherein an aperture goes through the main body, thereby allowing access to the at least one cavity.

[00103] Aspect 63. The product of aspect 62, wherein the at least one cavity is configured to hold liquid. [00104] Aspect 64. The product of any one of aspects 62-63, wherein the coupling the first portion to the second portion comprises at least one of sewing or ultrasonically welding the first portion to the second portion.

[00105] Aspect 65. The product of any one of aspects 62-64, wherein the multilayer structure comprises a four-layer structure.

[00106] Aspect 66. The product of any one of aspects 62-65, wherein the multilayer structure comprises structure with at least two layers.

[00107] Aspect 67. The product of any one of aspects 62-66, wherein the knitting the main body comprises warp knitting the main body.

[00108] Aspect 68. The product of any one of aspects 62-67, wherein the first portion and the second portion each have a length, wherein a portion of the first portion coupled to a portion of the second portion has a length less than or equal to twenty-five percent of the length of the first portion and the second portion.

[00109] Aspect 69. The product of any one of aspects 62-68, wherein the main body comprises a polyester.

[00110] Aspect 70. The product of any one of aspects 62-69, a plurality of pockets are coupled to the main body.

[00111] FIG. 5 shows an example method 500 of making a hydration pack. The hydration pack may be like the hydration pack 100 in FIG. 1. At step 510, a body of the hydration pack may be knit. The body may be similar to main body 101 or a portion of the main body 101 in FIG. 1. The body may be similar to any of bodies 201, 301, and/or 401. The body may be knit using a warp knitting technique. The body may be knit using a warp knitting machine. The body may be knit using a flat-bed knitting machine.

[00112] The body may comprise a unitary piece of knitted fabric. The body may have a tubular shape or another three-dimensional shape. The three-dimensional shape may define a cavity. The body may be flattened. For example, the body may be laid on a surface. The flattened body may form at least one layer overlapping another layer. The flattened body may have a first portion and a second portion. For example, the first portion and the second portion may be adjacent open ends of the three-dimensional shape. As another example, the first portion and the second portion may be adjacent closed sides of the flattened body. The first portion and the second portion may comprise halves of the flattened body. [00113] At step 515, the first portion of the body may be folded to be disposed adjacent the second portion of the main body. The first portion may be folded over an axis, such as the y- axis in FIG. 2, the z-axis in FIG. 3, or the z-axis in FIG. 4. The first portion may be folded over an axis running through a center of the flattened body. The first portion may be folded manually. The first portion may be folded by a machine, such as a press or a mechanical claw.

[00114] The first portion folded to be disposed adjacent the second portion may define a multilayer structure of the body. As an example, the body may comprise two, four, six, eight, or more layers. Two or more of the layers may form the cavity. As an illustrative example, if the main body comprises four layers, two adjacent layers of the four layers may form the cavity.

[00115] At step 520, the first portion may be coupled to the second portion. As examples, the first portion may be sewn, glued, or ultrasonically welded. The first portion may be coupled to the second portion by a machine, such as a sewing machine or a glue extruder.

The coupling of the first portion to the second portion may form a seam. The seam may run along an edge of the body.

[00116] An open end of the body may be closed. The cavity may be closed. A portion of the body or the cavity may be left open, such as to form an aperture. The aperture may allow access to liquid stored in the cavity. A bladder or a pouch may be disposed in the cavity.

[00117] One or more pieces of material may be coupled to the body. One or more pockets may be coupled to the body. One or more accessory components may be coupled to the main body. An aperture may be formed on the main body. For example, an opening may be cut on the main body to form the aperture. A tube or a nozzle may be coupled at the aperture. The tube or the nozzle may allow a user to draw water from the cavity.