Patent Publication Number: US-2015067973-A1

Title: Method Of Manufacturing A Contoured Fluid-Filled Chamber With Tensile Structures

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This non-provisional U.S. patent application claims priority to and is a Division of prior U.S. patent application Ser. No. 13/049,278, which was filed in the U.S. Patent and Trademark Office on Mar. 16, 2011 and entitled “Method Of Manufacturing A Contoured Fluid-Filled Chamber With Tensile Structures,” such prior U.S. patent application being entirely incorporated herein by reference. 
    
    
     BACKGROUND 
     Articles of footwear generally include two primary elements, an upper and a sole structure. The upper is formed from a variety of material elements (e.g., textiles, foam, leather, and synthetic leather) that are stitched or adhesively bonded together to form a void on the interior of the footwear for comfortably and securely receiving a foot. An ankle opening through the material elements provides access to the void, thereby facilitating entry and removal of the foot from the void. In addition, a lace is utilized to modify the dimensions of the void and secure the foot within the void. 
     The sole structure is located adjacent to a lower portion of the upper and is generally positioned between the foot and the ground. In many articles of footwear, including athletic footwear, the sole structure conventionally incorporates an insole, a midsole, and an outsole. The insole is a thin compressible member located within the void and adjacent to a lower surface of the void to enhance footwear comfort. The midsole, which may be secured to a lower surface of the upper and extends downward from the upper, forms a middle layer of the sole structure. In addition to attenuating ground reaction forces (i.e., providing cushioning for the foot), the midsole may limit foot motions or impart stability, for example. The outsole, which may be secured to a lower surface of the midsole, forms the ground-contacting portion of the footwear and is usually fashioned from a durable and wear-resistant material that includes texturing to improve traction. 
     The conventional midsole is primarily formed from a foamed polymer material, such as polyurethane or ethylvinylacetate, that extends throughout a length and width of the footwear. In some articles of footwear, the midsole may incorporate a variety of additional footwear elements that enhance the comfort or performance of the footwear, including plates, moderators, fluid-filled chambers, lasting elements, or motion control members. In some configurations, any of these additional footwear elements may be located between the midsole and the upper or between the midsole and the outsole, may be embedded within the midsole, or may be encapsulated by the foamed polymer material of the midsole, for example. Although many conventional midsoles are primarily formed from a foamed polymer material, fluid-filled chambers or other non-foam structures may form part of or a majority of some midsole configurations. 
     SUMMARY 
     Various features of a fluid-filled chamber, which may be incorporated into articles of footwear and other products, are disclosed below. In one configuration, an article of footwear incorporates a sole structure comprising a midsole and an outsole. The midsole includes a fluid-filled chamber comprising an outer barrier, a tensile structure, and a window portion. The outer barrier defines an interior void. The tensile structure is located within the interior void and is bonded to the outer barrier. The window portion is located around at least part of a periphery of the tensile structure. The window portion has a first area with a first extent of outward protrusion and a second area with a second extent of outward protrusion, the first extent of outward protrusion exceeding the second extent of outward protrusion. The outsole is secured to the midsole and forms at least part of a ground-contacting surface of the footwear. The tensile structure has a first height at a first part adjacent to the first area and a second height at a second part adjacent to the second area, the first height being substantially the same as the second height. 
     In another configuration, an article of footwear incorporates a sole structure comprising a midsole and an outsole. The midsole includes a fluid-filled chamber comprising an outer barrier, a tensile structure, and a window portion. The outer barrier has an upper portion, an opposite lower portion, and a peripheral edge. The tensile structure is located within the outer barrier and has a first surface secured to the upper portion and a second surface secured to the lower portion. The window portion extends from at least part of the tensile structure to a periphery of the outer barrier. The window portion has a first perimeter at a first position and a second perimeter at a second position, the first perimeter being greater than the second perimeter. The outsole is secured to the midsole and forms at least part of a ground-contacting surface of the footwear. The first perimeter and the second perimeter are located substantially opposite each other on the chamber, and one of the first perimeter and the second perimeter is located on a lateral side of the chamber. 
     Various features of a method of manufacturing a fluid-filled chamber, which may be incorporated into articles of footwear and other products, are also disclosed below. One method of manufacturing comprises steps of locating, positioning, securing, sealing, forming, and pressurizing. The step of locating includes locating a first polymer layer and a second polymer layer between a first mold portion and a second mold portion. A first surface of the first mold portion and a first surface of the second mold portion cooperatively define a peripheral cavity with a first region and a second region. An inward extent of the first region exceeds an inward extent of the second region. The step of positioning includes positioning a tensile structure between the first polymer layer and the second polymer layer. The step of securing includes securing the tensile structure to the first polymer layer and the second polymer layer. The step of sealing includes sealing the first polymer layer to the second polymer layer to form the chamber. The step of forming includes forming at least part of a peripheral portion of the chamber by drawing a first area of the chamber against the first region of the peripheral cavity, and drawing a second area of the chamber against the second region of the peripheral cavity. The step of pressurizing includes pressurizing the chamber. 
     Another method of manufacturing comprises steps of locating, positioning, compressing, forming, pressurizing, and incorporating. The step of locating includes locating a first polymer layer and a second polymer layer between a pair of mold portions. Each mold portion has a molding surface. At least one of the molding surfaces including a peripheral indentation with a first region having a first inward extent and a second region having a second inward extent, the first inward extent exceeding the second inward extent. The step of positioning includes positioning a tensile structure between the mold portions. The step of compressing includes compressing the mold portions together to secure the tensile structure to each of the polymer layers, to seal the polymer layers to each other, and to form a chamber. The step of forming includes forming at least part of a peripheral portion of the chamber by drawing a first area of the chamber against the first region of the peripheral indentation, and drawing a second area of the chamber against the second region of the peripheral indentation. The step of pressurizing includes pressurizing the chamber to form a window portion around at least part of a periphery of the tensile structure, the window portion having a first area with a first extent of outward protrusion and a second area with a second extent of outward protrusion, the first extent of outward protrusion exceeding the second extent of outward protrusion. The step of incorporating includes incorporating the chamber into the article of footwear. 
     The advantages and features of novelty characterizing aspects of the invention are pointed out with particularity in the appended claims. To gain an improved understanding of the advantages and features of novelty, however, reference may be made to the following descriptive matter and accompanying Figures that describe and illustrate various configurations and concepts related to the invention. 
    
    
     
       FIGURE DESCRIPTIONS 
       The foregoing Summary and the following Detailed Description will be better understood when read in conjunction with the accompanying Figures. 
         FIG. 1  is a lateral side elevational view of an article of footwear incorporating a fluid-filled chamber. 
         FIG. 2  is a cross-sectional view of the article of footwear, as defined by section line  2 - 2  in  FIG. 1 . 
         FIG. 3  is a perspective view of the chamber. 
         FIG. 4  is a top plan view of the chamber. 
         FIG. 5  is a medial side elevational view of the chamber. 
         FIGS. 6A-6C  are cross-sectional views of the chamber, as defined by section lines  6 A- 6 A through  6 C- 6 C in  FIG. 4 . 
         FIG. 7  is a perspective view of a mold that may be utilized for a process for manufacturing the chamber. 
         FIGS. 8A-8E  are side elevational views of the mold depicting steps in the process for manufacturing the chamber. 
         FIGS. 9A-9E  are schematic cross-sectional views of the mold, as defined by section lines  9 A- 9 A through  9 E- 9 E in  FIGS. 8A-8E , depicting steps in the process for manufacturing the chamber. 
         FIGS. 10A-10E  are top plan views corresponding with  FIG. 4  and depicting additional configurations of the chamber. 
         FIGS. 11A-11L  are schematic cross-sectional views corresponding with  FIG. 9E  and depicting steps in additional processes for manufacturing the chamber 
         FIG. 12  is a top plan view of an alternate configuration of a fluid-filled chamber. 
         FIG. 13  is a medial side elevational view of the alternate configuration of the chamber. 
     
    
    
     DETAILED DESCRIPTION 
     The following discussion and accompanying Figures disclose various configurations of fluid-filled chambers and methods for manufacturing the chambers. Although the chambers are disclosed with reference to footwear having a configuration that is suitable for running, concepts associated with the chambers may be applied to a wide range of athletic footwear styles, including basketball shoes, cross-training shoes, football shoes, golf shoes, hiking shoes and boots, ski and snowboarding boots, soccer shoes, tennis shoes, and walking shoes, for example. Concepts associated with the chambers may also be utilized with footwear styles that are generally considered to be non-athletic, including dress shoes, loafers, and sandals. In addition to footwear, the chambers may be incorporated into other types of apparel and athletic equipment, including helmets, gloves, and protective padding for sports such as football and hockey. Similar chambers may also be incorporated into cushions and other compressible structures utilized in household goods and industrial products. Accordingly, chambers incorporating the concepts disclosed herein may be utilized with a variety of products. 
     General Footwear Structure 
     An article of footwear  10  is depicted in  FIGS. 1-2  as including an upper  20  and a sole structure  30 . For reference purposes, footwear  10  may be divided into three general regions: a forefoot region  11 , a midfoot region  12 , and a heel region  13 , as shown in  FIG. 1 . Forefoot region  11  generally includes portions of footwear  10  corresponding with the toes and the joints connecting the metatarsals with the phalanges. Midfoot region  12  generally includes portions of footwear  10  corresponding with the arch area of the foot. Heel region  13  generally includes portions of footwear  10  corresponding with rear portions of the foot, including the calcaneus bone. Regions  11 - 13  are not intended to demarcate precise areas of footwear  10 . Rather, regions  11 - 13  are intended to represent general areas of footwear  10  to aid in the following discussion. In addition to being applied to footwear  10 , regions  11 - 13  may also be applied to upper  20 , sole structure  30 , and individual elements thereof. Footwear  10  also includes a lateral side  14  and a medial side  15 , as shown in  FIGS. 1-2 . Lateral side  14  and medial side  15  also extend through each of regions  11 - 13  and correspond with opposite sides of footwear  10 . As with regions  11 - 13 , sides  14  and  15  represent general areas of footwear  10  to aid in the following discussion, and may also be applied to upper  20 , sole structure  30 , and individual elements thereof in addition to being applied to footwear  10 . 
     Upper  20  is depicted as having a substantially conventional configuration incorporating a plurality of material elements (e.g., textile, foam, leather, and synthetic leather) that are stitched, adhered, bonded, or otherwise joined together to form an interior void for securely and comfortably receiving a foot. The material elements may be selected and located with respect to upper  20  in order to selectively impart properties of durability, air-permeability, wear-resistance, flexibility, and comfort, for example. An ankle opening  21  in heel region  13  provides access to the interior void. In addition, upper  20  may include a lace  22  that is utilized in a conventional manner to modify the dimensions of the interior void, thereby securing the foot within the interior void and facilitating entry and removal of the foot from the interior void. Lace  22  may extend through apertures in upper  20 , and a tongue portion of upper  20  may extend between the interior void and lace  22 . Upper  20  may also incorporate a sockliner  23  that is located within the void in upper  20  and adjacent a plantar (i.e., lower) surface of the foot to enhance the comfort of footwear  10 . Given that various aspects of the present application primarily relate to sole structure  30 , upper  20  may exhibit the general configuration discussed above or the general configuration of practically any other conventional or non-conventional upper. Accordingly, the overall structure of upper  20  may vary significantly. 
     Sole structure  30  is secured to upper  20  and has a configuration that extends between upper  20  and the ground. In effect, therefore, sole structure  30  is located to extend between the foot and the ground. In addition to attenuating ground reaction forces (i.e., providing cushioning for the foot), sole structure  30  may provide traction, impart stability, and limit various foot motions, such as pronation. The primary elements of sole structure  30  are a midsole  31  and an outsole  32 . Midsole  31  may incorporate a polymer foam material, such as polyurethane or ethylvinylacetate. Midsole  31  may also incorporate a fluid-filled chamber  33 . In addition to the polymer foam material and chamber  33 , midsole  31  may incorporate one or more other footwear elements that enhance the comfort, performance, or ground reaction force attenuation properties of footwear  10 , including plates, moderators, lasting elements, or motion control members. 
     Outsole  32 , which may be absent in some configurations of footwear  10 , is secured to a lower surface of midsole  31  and forms at least part of a ground-contacting surface of footwear  10 . Outsole  32  may be formed from a rubber material that provides a durable and wear-resistant surface for engaging the ground. In addition, outsole  32  may also be textured to enhance the traction (i.e., friction) properties between footwear  10  and the ground. In further configurations, and depending upon the manner in which midsole  31  incorporates the polymer foam material, chamber  33 , or both, outsole  32  may be secured to the polymer foam material alone, to chamber  33  alone, or to both the polymer foam material and chamber  33 . 
     As incorporated into footwear  10 , chamber  33  has a shape that extends through substantially all of footwear  10 , from forefoot region  11  to heel region  13  and also from lateral side  14  to medial side  15 , thereby having a shape that corresponds with an outline of the foot and extends under substantially all of the foot. Accordingly, when the foot is located within upper  20 , chamber  33  extends under the foot in order to attenuate ground reaction forces that are generated when sole structure  30  is compressed between the foot and the ground during various ambulatory activities, such as running and walking. In other configurations, chamber  33  may extend through less than all of footwear  10 . For example, chamber  33  may extend only through forefoot region  11 , or only through midfoot region  12 , or only through heel region  13 . Alternatively, chamber  33  may extend only through lateral side  14  of footwear  10 , or only through medial side  15  of footwear  10 . Chamber  33  may also extend through any combination of regions and sides. That is, in various configurations, chamber  33  may extend through any portion of footwear  10 . 
     As depicted in  FIGS. 1-2 , chamber  33  is positioned substantially surrounded by or entirely encapsulated within a polymer foam material of midsole  31  and is secured to the polymer foam material. In some configurations, however, chamber  33  may be only partially encapsulated by a polymer foam material of midsole  31 , or may be above a polymer foam material of midsole  31 , or may be below a polymer foam material of midsole  31 . In other configurations, chamber  33  may be secured to a plate or other structure within midsole  31 . In further configurations, the polymer foam material of midsole  31  may be absent and chamber  33  may be secured to both upper  20  and outsole  32 . Additionally, in various configurations, chamber  33  may be secured to outsole  32 . Accordingly, the overall shape of chamber  33  and the manner in which chamber  33  is incorporated into footwear  10  may vary significantly. 
     Although chamber  33  is depicted and discussed as being a sealed chamber within footwear  10 , chamber  33  may also be a component of a fluid system within footwear  10 . More particularly, pumps, conduits, and valves may be joined with chamber  33  to provide a fluid system that pressurizes chamber  33  with air from the exterior of footwear  10  or a reservoir within footwear  10 . As examples, chamber  33  may be utilized in combination with any of the fluid systems disclosed in U.S. Pat. No. 7,210,249 to Passke, et al. and U.S. Pat. No. 7,409,779 to Dojan, et al. 
     Chamber Configuration 
     Chamber  33  is depicted individually in  FIGS. 3-6C  in an initial configuration that is suitable for footwear applications. Chamber  33  has a contoured configuration, and when incorporated into footwear  10 , chamber  33  corresponds with substantially all of footwear  10 . When the foot is located within upper  20 , chamber  33  extends under the foot in order to attenuate ground reaction forces that are generated when sole structure  30  is compressed between the foot and the ground during various ambulatory activities, such as running and walking. In other configurations, chamber  33  may have an alternate extent, such as extending under a forefoot area of the foot, or a heel area of the foot, for example. Additionally, although chamber  33  is depicted as being within a polymer foam material of midsole  31 , in some configurations of footwear  10 , chamber  33  may form at least part of a sidewall of midsole  31 . 
     The primary elements of chamber  33  are an outer barrier  40  and tensile structures  50   a  and  50   b . Barrier  40  ( a ) forms an exterior of chamber  33 , (b) defines an interior void that receives both a pressurized fluid and tensile structures  50   a - 50   b , and (c) provides a durable sealed barrier for retaining the pressurized fluid within chamber  33 . The polymer material of barrier  40  includes (a) a first barrier portion  41  oriented toward upper  20  that may form an upper portion of barrier  40 , (b) an opposite second barrier portion  42  oriented toward outsole  32  that may form a lower portion of barrier  40 , and (c) a peripheral edge  43  that extends around a periphery of chamber  33  and between barrier portions  41  and  42 . 
     As depicted in  FIGS. 3-6C , tensile structures  50   a - 50   b  are located within the interior void and may include tensile members such as textile tensile members. In other configurations, tensile structures may include elements that are not textile tensile members, such as any of the tether elements disclosed in U.S. patent application Ser. No. 12/630,642 to Peyton and U.S. patent application Ser. No. 12/777,167 to Peyton. In some configurations, tensile member  50  may be formed from, or be formed to include a foam tensile member such as any of the foam tensile members disclosed in U.S. Pat. No. 7,131,218 to Schindler, U.S. Pat. No. 7,588,654 to Schindler et al., and U.S. Pat. No. 7,591,919 to Schindler et al. 
     Tensile structures  50   a - 50   b  may include upper tensile layers  51   a  and  51   b , opposite lower tensile layers  52   a  and  52   b , and pluralities of connecting members  53   a  and  53   b , respectively, that extend between tensile layers  51   a - 51   b  and  52   a - 52   b . Upper tensile layers  51   a - 51   b  are secured to inner surfaces of first barrier portion  41  and lower tensile layers  52   a - 52   b  are secured to inner surfaces of second barrier portion  42 . Connecting members  53   a - 53   b  may include yarns, fibers, or filaments formed of a variety of materials, and may be positioned across lengths and widths of tensile structures  52   a - 52   b  at relatively sparse densities, relatively packed densities, or any other densities. Although discussed in greater detail below, either adhesive bonding or thermobonding may be utilized to secure tensile structures  50   a - 50   b  to barrier  40 . Tensile structures  50   a - 50   b  may be located in different areas of chamber  33  and may have different heights. 
     In addition, window portion  45  of chamber  33  is located around the peripheries of tensile structures  50   a - 50   b , extending from at least part of each of tensile structures  50   a - 50   b  to a periphery of outer barrier  40 . Each of first window area  47   a  and second window area  48   a  extends from at least part of tensile structure  50   a  to a periphery of outer barrier  40 , while each of first window area  47   b  and second window area  48   b  extends from at least part of the periphery of tensile structure  50   b  to a periphery of outer barrier  40 . In addition, first window areas  47   a - 47   b  are positioned on lateral side  14  and within midfoot region  12  of chamber  33 , and second window areas  48   a - 48   b  are positioned on medial side  15  and within midfoot region  12  of chamber  33 . 
     Each of window areas  47   a - 47   b  and  48   a - 48   b  may have an extent of outward protrusion, and the extent of outward protrusion between various window areas  47   a - 47   b  and  48   a - 48   b  may differ. For example, one or more window areas  47   a - 47   b  and  48   a - 48   b  may have a greater extent of outward protrusion than one or more other window areas  47   a - 47   b  and  48   a - 48   b . At the same time, the extent of outward protrusion of window areas  47   a - 47   b  and  48   a - 48   b  may be substantially proportional to dimensions corresponding with tensile structures  50   a  and  50   b , respectively, such as the heights of tensile structures  50   a  and  50   b.    
     A wide range of polymer materials may be utilized for barrier  40 . In selecting materials for barrier  40 , engineering properties of the materials (e.g., tensile strength, stretch properties, fatigue characteristics, dynamic modulus, and loss tangent) as well as the ability of the materials to prevent the diffusion of the fluid contained by barrier  40  may be considered. When formed of thermoplastic urethane, for example, barrier  40  may have a thickness of approximately 1.0 millimeter, but the thickness may range from less than 0.25 to more than 2.0 millimeters, for example. In addition to thermoplastic urethane, examples of polymer materials that may be suitable for barrier  40  include polyurethane, polyester, polyester polyurethane, and polyether polyurethane. Barrier  40  may also be formed from a material that includes alternating layers of thermoplastic polyurethane and ethylene-vinyl alcohol copolymer, as disclosed in U.S. Pat. Nos. 5,713,141 and 5,952,065 to Mitchell, et al. A variation upon this material may also be utilized, wherein a center layer is formed of ethylene-vinyl alcohol copolymer, layers adjacent to the center layer are formed of thermoplastic polyurethane, and outer layers are formed of a regrind material of thermoplastic polyurethane and ethylene-vinyl alcohol copolymer. Another suitable material for barrier  40  is a flexible microlayer membrane that includes alternating layers of a gas barrier material and an elastomeric material, as disclosed in U.S. Pat. Nos. 6,082,025 and 6,127,026 to Bonk, et al. Additional suitable materials are disclosed in U.S. Pat. Nos. 4,183,156 and 4,219,945 to Rudy. Further suitable materials include thermoplastic films containing a crystalline material, as disclosed in U.S. Pat. Nos. 4,936,029 and 5,042,176 to Rudy, and polyurethane including a polyester polyol, as disclosed in U.S. Pat. Nos. 6,013,340, 6,203,868, and 6,321,465 to Bonk, et al. 
     A variety of processes may be utilized to manufacture chamber  33 . In general, the manufacturing processes involve (a) securing a pair of polymer sheets, which form barrier portions  41  and  42  as well as peripheral edge  43 , to opposite sides of tensile structures  50   a - 50   b  (i.e., to tensile layers  51   a - 51   b  and  52   a - 52   b ) and ( b ) forming a peripheral bond  44  that joins a periphery of the polymer sheets and may extend around peripheral edge  43 . Peripheral bond  44  is depicted as being adjacent to the upper surface of chamber  33 , but may be positioned between the upper and lower surfaces of chamber  33 , or may be adjacent to the lower surface of chamber  33 . The thermoforming process may also (a) locate tensile structures  50   a - 50   b  within chamber  33 , and (b) bond tensile structures  50   a - 50   b  to each of barrier portions  41  and  42 . Although substantially all of the thermoforming process may be performed with a mold, as described in greater detail below, each of the various parts or steps of the process may be performed separately in forming chamber  33 . That is, a variety of other methods may be utilized to form chamber  33 . 
     In order to facilitate bonding between tensile structures  50   a - 50   b  and barrier  40 , polymer supplemental layers may be applied to any of tensile layers  51   a - 51   b  and  52   a - 52   b . When heated, the supplemental layers soften, melt, or otherwise begin to change state so that contact with barrier portions  41  and  42  induces material from each of barrier  40  and the supplemental layers to intermingle or otherwise join with each other. Upon cooling, therefore, the supplemental layers are permanently joined with barrier  40 , thereby joining tensile structures  50   a - 50   b  with barrier  40 . In some configurations, thermoplastic threads or strips may be present within tensile layers  51   a - 51   b  and  52   a - 52   b  to facilitate bonding with barrier  40 , as disclosed in U.S. Pat. No. 7,070,845 to Thomas, et al., or an adhesive may be utilized to secure barrier  40  to any of tensile structures  50   a - 50   b.    
     Following the thermoforming process, or as part of the thermoforming process, a fluid may be injected into the interior void and pressurized between zero and three-hundred-fifty kilopascals (i.e., approximately fifty-one pounds per square inch) or more. The pressurized fluid exerts an outward force upon barrier  40 , which tends to separate barrier portions  41  and  42 . Tensile structures  50   a - 50   b , however, are secured to each of barrier portions  41  and  42  in order to impose an intended shape upon chamber  33  when pressurized. More particularly, connecting members  53   a - 53   b  extending across the interior void are placed in tension by the outward force of the pressurized fluid upon barrier  40 , thereby preventing barrier  40  from expanding outward and causing chamber  33  to retain an intended shape. Whereas peripheral bond  44  joins the polymer sheets to form a seal that prevents the fluid from escaping, tensile structures  50   a - 50   b  prevent barrier  40  from expanding outward or otherwise distending due to the pressure of the fluid. That is, tensile structures  50   a - 50   b  effectively limit the expansion of chamber  33  to retain an intended shape of barrier portions  41  and  42 . 
     The lengths of connecting members within each plurality of connecting members  53   a - 53   b  are substantially constant throughout tensile structures  50   a - 50   b , which imparts the parallel configuration to each of tensile layers  51   a - 51   b  and  52   a - 52   b . In some configurations, however, the lengths of connecting members within at least one plurality of connecting members  53   a - 53   b  may vary to impart a contoured configuration to chamber  33 . For example, chamber  33  may taper or may form a depression due to differences in the lengths of connecting members within any plurality of connecting members  53   a - 53   b . Examples of contoured tensile structures are disclosed in U.S. patent application Ser. No. 12/123,612 to Dua and Ser. No. 12/123,646 to Rapaport, et al. Additionally, tensile structures  50   a - 50   b  may include tensile members such as textile tensile members. That is, part of at least one of tensile structures  50   a - 50   b  may be formed of a textile tensile member. Textile tensile members may be cut or formed from a larger element of a spacer textile. Alternately, each of tensile elements  51   a - 51   b  and  52   a - 52   b  may be formed to have a variety of configurations through, for example, a flat-knitting process, as in U.S. patent application Ser. No. 12/123,612 to Dua. 
     Suitably configured, tensile structures  50   a - 50   b  may have any of a range of configurations, including the range of configurations disclosed in U.S. patent application Ser. No. 12/123,612 to Dua, U.S. patent application Ser. No. 12/123,646 to Rapaport, et al., and U.S. patent application Ser. No. 12/630,642 to Peyton. In some configurations, chamber  33  may incorporate a valve or other structure that permits the individual to adjust the pressure of the fluid. Additionally, chamber  33  may be incorporated into a fluid system, similar to a fluid system disclosed in U.S. Pat. No. 7,409,779 to Dojan, et al., that varies the pressure within barrier  40  depending upon, for example, the running style or weight of the wearer. 
     As depicted in  FIGS. 3-6C , chamber  33 , as well as tensile structures  50   a - 50   b  within chamber  33 , extend substantially throughout footwear  10 . Tensile structures  50   a - 50   b  are located in different areas of chamber  33 , or in different areas of barrier  40  that forms an exterior of chamber  33  and defines an interior void within chamber  33 . Tensile structure  50   a  is located in a first area of chamber  33 , or in a first area of barrier  40  and within the interior void. Tensile structure  50   b  is located in a second area of chamber  33 , or in a second area of barrier  40  and within the interior void. The first area and second area are in fluid communication with each other. Additionally, tensile structure  50   a  is substantially located in heel region  13  of footwear  10 , and tensile structure  50   b  is substantially located in midfoot region  12  and forefoot region  11  of footwear  10 . That is, tensile structure  50   b  is forward of tensile structure  50   a.    
     Additionally, each of tensile structures  50   a - 50   b  may have a different height than the other tensile structures  50   a - 50   b . For example, as depicted in  FIGS. 3-6C , tensile structure  50   a  has a height greater than tensile structure  50   b . In turn, the relative locations and differences of height of tensile structure  50   a - 50   b  impart a contoured configuration to footwear  10 . As depicted in  FIGS. 3-6C , the relative locations and differences of height of tensile structures  50   a - 50   b  impart contours including a taper from heel region  13  to forefoot region  11 . 
     As depicted in  FIGS. 3-6C , tensile structure  50   a  has a height greater than tensile structure  50   b . Correspondingly, first window area  47   a  and second window area  48   a  have greater extents of outward protrusion than first window area  47   b  and second window area  48   b . In contrast, the height at all parts of tensile structure  50   b  at all parts at which it is adjacent to window portion  45  is substantially the same. That is, a height of tensile structure  50   b  at a first part adjacent to first window area  47   b  is substantially the same as a height of tensile structure  50   b  at a second part adjacent to second window area  48   b . In some configurations, tensile structure  50   b  may include a first tensile member at the first part and a second tensile member at the second part, and both the first tensile member and the second tensile member may have substantially the same height. 
     At the same time, the extent of outward protrusion of first window area  47   b , located in midfoot region  12  and lateral side  14  of footwear  10 , exceeds the extent of outward protrusion of second window area  48   b , located in midfoot region  12  and medial side  15  of footwear  10 . The extent of outward protrusion of a particular window area may be a lateral spacing between a tensile structure and a periphery of chamber  33 . Alternatively, the extent of outward protrusion of a particular window area may be an overall extent, such as an area, in cross-section, of a space bounded by a tensile structure and by an outer barrier, or a volume of a portion of an interior void bounded by an outer barrier and a portion of a tensile structure located within the outer barrier. 
     In some configurations, window portion  45  may have a first perimeter at a first position, and a second perimeter at a second position, the first perimeter being greater than the second perimeter. Furthermore, the first perimeter and the second perimeter may be located substantially opposite each other on the chamber. For example, as depicted in  FIGS. 3-6C , window portion  45  has a first perimeter in first window area  47   b  and a second perimeter in second window area  48   b , and the first perimeter is greater than the second perimeter. 
     As depicted in  FIGS. 3-6C , first window area  47   b  and second window area  48   b  are located within midfoot region  12  and are substantially opposite each other on chamber  33 . In other configurations, first window areas and second window areas may be located in other regions of footwear  10 , such as heel region  13  or forefoot region  11 , while still being substantially opposite each other on chamber  33 . 
     As depicted in  FIGS. 3-6C , first window area  47   b  having the first perimeter is located on lateral side  14  of footwear  10 , and second window area  48   b  having the second perimeter is located on medial side  15  of footwear  10 , the first perimeter being greater than the second perimeter. In other configurations, a window area located on medial side  15  of footwear  10  may have the first perimeter, and a window area located on lateral side  14  of footwear  10  may have the second perimeter, the first perimeter being greater than the second perimeter. 
     In some configurations, peripheral edge  43  of chamber  33  may be spaced from a tensile structure by a first distance in a first window area and by a second distance in a second window area, the first distance being greater than the second distance. For example, as depicted in  FIGS. 3-6C , peripheral edge  43  is spaced from tensile structure  50   b  by a first distance in first window area  47   b , and is spaced from tensile structure  50   b  by a second distance in second window area  48   b , and the first distance is greater than the second distance. 
     Although depicted in  FIGS. 3-6C  as including two tensile structures  50   a - 50   b , various configurations of chamber  33  may include a different number of tensile structures. For example, in some configurations, chamber  33  may include only one tensile structure, whereas in other configurations, chamber  33  may include more than two tensile structures. Accordingly, in various configurations, chamber  33  may include any number of tensile structures, each of which may have any height, or any of the various configurations described above. 
     In other words, in various configurations, two or more tensile structures having various heights may be incorporated into different areas of a chamber  33 . One or more tensile structures may be located in a heel region, or in a midfoot region, or in a forefoot region of chamber  33 , and one or more other tensile structures may be located in different areas of chamber  33 . 
     The various configurations of chamber  33  described above may be incorporated into an article of footwear or any of a variety of other products, such as apparel, athletic equipment, cushions, and other compressible structures. By incorporating a plurality of tensile structures having different heights into different areas of chamber  33 , one or more properties of chamber  33  may be altered, such as a flexibility, stiffness, rigidity, tensile response, compressibility, or force attenuation property of chamber  33 . Additionally, an asymmetric medio-lateral shape may be imparted to chamber  33  without use of a tensile structure that is itself tapered or contoured. 
     Manufacturing Process 
     Although a variety of manufacturing processes may be utilized to form chamber  33 , an example of a suitable thermoforming process will now be discussed. With reference to  FIG. 7 , a mold  60  that may be utilized in the thermoforming process is depicted as including an upper mold portion  61  and a lower mold portion  62 . Mold  60  is utilized to form chamber  33  from a pair of polymer sheets that are molded and bonded to define barrier portions  41  and  42  as well as peripheral edge  43 , and the thermoforming process secures tensile structures  50   a - 50   b  within barrier  40 . More particularly, mold  60  ( a ) imparts shape to one of the polymer sheets in order to form first barrier portion  41 , (b) imparts shape to the other of the polymer sheets in order to form second barrier portion  42 , (c) imparts shape to the polymer sheets in order to form peripheral edge  43  and to form peripheral bond  44  to seal or otherwise join a periphery of the polymer sheets, (d) locates tensile structures  50   a - 50   b  within chamber  33 , and (e) bonds tensile structures  50   a - 50   b  to each of barrier portions  41  and  42 . 
     Additionally, various surfaces of the first mold portion and the second mold portion may define a peripheral cavity, or peripheral indentation, having a first peripheral region and a second peripheral region, in which an inward extent of the first peripheral region is greater than an inward extent of the second peripheral region. As depicted in  FIGS. 7-9E , a molding surface of second mold portion  62  defines peripheral cavity  63 , while a molding surface of first mold portion is substantially flat. Peripheral cavity  63  includes a first peripheral region  67  and a second peripheral region  68 . First peripheral region  67  may correspond with a lateral side and a midfoot region of the chamber to be formed in the mold, while second peripheral region  68  may correspond with a medial side and a midfoot region of the chamber to be formed in the mold. 
     The inward extent of first peripheral region  67  exceeds the inward extent of second peripheral region  68 . The inward extent of a particular peripheral region may be a distance perpendicular to the surface of each mold portion mold oriented to face the polymer sheets. That is, the inward extent may be a distance extending away from the face of each mold portion that includes the surfaces against which the polymer sheets will be drawn to form chamber  33 . Alternatively, the inward extent of a particular peripheral region may be an overall extent, such as an area, in cross-section, of an inward protrusion, or a volume of an inward protrusion. 
     In this example manufacturing process, each of tensile structures  50   a - 50   b  may be a textile tensile member. In other manufacturing processes, each of tensile structures  50   a - 50   b  may include one or more textile tensile members, and may also include one or more elements that are not textile tensile members, such as tether elements. 
     In preparation for the manufacturing process, various elements forming chamber  33  may be obtained and organized. For example, an upper polymer layer  71  and a lower polymer layer  72 , which form barrier  40 , may be cut to a desired shape. Tensile structures  50   a - 50   b  are in a compressed state at this stage of the manufacturing process, wherein textile layers  51   a - 51   b  and  52   a - 52   b  lie adjacent to each other and connecting members  53   a - 53   b  are in a collapsed state. Upon completion of the manufacturing process, when chamber  33  is pressurized, tensile structures  50   a - 50   b  are placed in tension, which spaces textile layers  51   a - 51   b  and  52   a - 52   b  from each other and induces connecting members  53   a - 53   b  to straighten. 
     In manufacturing chamber  33 , one or more of upper polymer layer  71 , lower polymer layer  72 , and tensile structures  50   a - 50   b  are heated to a temperature that facilitates bonding between the components. Depending upon the specific materials utilized for tensile structures  50   a - 50   b  and polymer layers  71  and  72 , which form barrier  40 , suitable temperatures may range from 120 to 200 degrees Celsius (248 to 392 degrees Fahrenheit) or more. Various radiant heaters or other devices may be utilized to heat the components of chamber  33 . In some manufacturing processes, mold  60  may be heated such that contact between mold  60  and the components of chamber  33  raises the temperature of the components to a level that facilitates bonding. 
     Following heating, the components of chamber  33  are located between mold portions  61  and  62 , as depicted in  FIGS. 8A and 9A . In order to properly position the components, a shuttle frame or other device may be utilized. Once positioned, mold portions  61  and  62  translate toward each other and begin to close upon the components such that (a) upper mold portion  61  contacts upper polymer layer  71 , (b) ridge  64  of lower mold portion  62  contacts lower polymer layer  72 , and (c) polymer layers  71  and  72  begin bending around tensile structures  50   a - 50   b  so as to extend into a cavity within mold  60 , as depicted in  FIGS. 8B and 9B . The components are thus located relative to mold  60  and initial shaping and positioning has occurred. 
     At the stage depicted in  FIGS. 8B and 9B , air may be partially evacuated from the area around polymer layers  71  and  72  through various vacuum ports in mold portions  61  and  62 . The purpose of evacuating the air is to draw polymer layers  71  and  72  into contact with the various contours of mold  60 . This ensures that polymer layers  71  and  72  are properly shaped in accordance with the contours of mold  60 . At least part of a peripheral portion or window portion of the chamber may be formed by drawing a first part of polymer layers  71  and  72  against first peripheral region  67 , and by drawing a second part of polymer layers  71  and  72  against second peripheral region  68 . For example, first window area  47   b  may be formed by drawing a first part of polymer layer  72  against first peripheral region  67 , and second window area  48   b  may be formed by drawing a second part of polymer layer  72  against second peripheral region  68 . 
     In some configurations, peripheral cavity  63  may be cooperatively defined by both mold portions. That is, a portion of peripheral cavity  63  may be defined by peripheral regions of second mold portion  62 , and another portion of peripheral cavity  63  may be defined by peripheral regions of first mold portion  61 . In such cases, an inward extent of peripheral cavity  63  may be an aggregate extent of first peripheral regions in mold portions  61  and  62 , or an aggregate extent of second peripheral regions in mold portions  61  and  62 . 
     Note that polymer layers  71  and  72  may stretch in order to extend around tensile structures  50   a - 50   b  and into mold  60 . In comparison with the thickness of barrier  40  in chamber  33 , polymer layers  71  and  72  may exhibit greater original thickness. This difference between the original thicknesses of polymer layers  71  and  72  and the resulting thickness of barrier  40  may occur as a result of the stretching taking place at this stage of the thermoforming process. 
     A movable insert  65  that is supported by various springs  66  may depress to place a specific degree of pressure upon the components, thereby bonding and securing polymer layers  71  and  72  to opposite surfaces of tensile structures  50   a - 50   b . Movable insert  65  includes peripheral cavity  63  that forms peripheral edge  43  from lower polymer layer  72 . In some configurations of mold  60 , movable insert  65  and springs  66  may be absent, and features such as peripheral regions  67  and  68  may instead be incorporated into lower mold portion  62 . 
     As depicted in  FIGS. 7-9E , polymer layers  71  and  72  are thermobonded to tensile structures  50   a - 50   b , but in other manufacturing processes, polymer layers  71  and  72  may be otherwise secured to tensile structures  50   a - 50   b . For example, polymer layers  71  and  72  may be secured to tensile layers  51   a - 51   b  and  52   a - 52   b  by use of thermoplastic threads or strips, as disclosed in U.S. Pat. No. 7,070,845 to Thomas, et al., or an adhesive. 
     As mold  60  closes further, upper mold portion  61  and ridge  64  bond upper polymer layer  71  to lower polymer layer  72 , as depicted in  FIGS. 8C and 9C , thereby forming peripheral bond  44 . Furthermore, portions of ridge  64  that extend away from tensile structures  50   a - 50   b  form a bond between other areas of polymer layers  71  and  72 , contributing to the formation of inflation conduit  73 . 
     In order to provide a second means for drawing polymer layers  71  and  72  into contact with the various contours of mold  60 , the area between polymer layers  71  and  72  and proximal to tensile structures  50   a - 50   b  may be pressurized. During a preparatory stage of this method, an injection needle may be located between polymer layers  71  and  72 , and the injection needle may be located such that ridge  64  envelops the injection needle when mold  60  closes. A gas may then be ejected from the injection needle such that polymer layers  71  and  72  engage ridge  64 . Inflation conduit  73  may thereby be formed (see  FIG. 8D ) between polymer layers  71  and  72 . The gas may then pass through inflation conduit  73 , thereby entering and pressurizing the area proximal to tensile structures  50   a - 50   b  and between polymer layers  71  and  72 . In combination with the vacuum, the internal pressure ensures that polymer layers  71  and  72  contact the various surfaces of mold  60 . 
     As discussed above, a supplemental layer of a polymer material or thermoplastic threads may be applied to textile layers  51   a - 51   b  and  52   a - 52   b  in order to facilitate bonding between tensile structures  50   a - 50   b  and barrier  40 . The pressure exerted upon the components by movable insert  65  ensures that the supplemental layer or thermoplastic threads form a bond with polymer layers  71  and  72 . 
     When bonding is complete, mold  60  is opened and chamber  33  and excess portions of polymer layers  71  and  72  are removed and permitted to cool, as depicted in  FIGS. 8D and 9D . A fluid may be injected into chamber  33  through the inflation needle and inflation conduit  73 . Upon exiting mold  60 , tensile structures  50   a - 50   b  remain in the compressed configuration. When chamber  33  is pressurized, however, the fluid places an outward force upon barrier  40 , which tends to separate barrier portions  41  and  42 , thereby placing tensile structures  50   a - 50   b  in tension and imparting a contoured configuration to chamber  33 . Chamber  33  may be pressurized to form window portion  45  at the peripheries of tensile structures  50   a - 50   b  and extending from at least part of each tensile structure  50   a - 50   b  to a periphery of outer barrier  40 . An inward extent of first peripheral region  67  against which polymer layers  71  and  72  were drawn may exceed an inward extent of second peripheral region  68 . In turn, in chamber  33  as pressurized, an extent of outward protrusion of first window area  47   b  may exceed an extent of outward protrusion of second window area  48   b.    
     In addition, a sealing process is utilized to seal inflation conduit  73  adjacent to chamber  33  after pressurization. The excess portions of polymer layers  71  and  72  are then removed, thereby completing the manufacture of chamber  33 , as depicted in  FIGS. 8E and 9E . As an alternative, the order of inflation and removal of excess material may be reversed. As a final step in the process, chamber  33  may be tested and then incorporated into midsole  31  of footwear  10 . 
     Further Chamber Configurations 
     As depicted in  FIGS. 1-6C , chamber  33  corresponds with substantially all of footwear  10 . In other configurations, chamber  33  may correspond with other portions of footwear  10 . For example, as depicted in  FIG. 10A , chamber  33  corresponds with heel region  13  of footwear  10 , and includes a first tensile structure  50   a  and a second tensile structure  50   b , first tensile structure  50   a  having a height less than second tensile structure  50   b . Correspondingly, first window area  47   a  and second window area  48   a  have lesser extents of outward protrusion than first window area  47   b  and second window area  48   b.    
     In an alternate example, as depicted in  FIG. 10B , chamber  33  corresponds with heel region  13  of footwear  10 , and includes a first tensile structure  50   a  and a second tensile structure  50   b , first tensile structure  50   a  having a height greater than second tensile structure  50   b . Correspondingly, first window area  47   a  and second window area  48   a  have greater extents of outward protrusion than first window area  47   b  and second window area  48   b.    
     In another example, as depicted in  FIG. 10C , chamber  33  corresponds with portions of midfoot region  12  and forefoot region  11  of footwear  10 , and includes a first tensile structure  50   a  and a second tensile structure  50   b , first tensile structure  50   a  having a height greater than second tensile structure  50   b . Correspondingly, first window area  47   a  and second window area  48   a  have greater extents of outward protrusion than first window area  47   b  and second window area  48   b.    
     Additionally, one or more regions of chamber  33  may be formed or shaped to accommodate additional portions of article of footwear  10 . For example, in embodiments in which chamber  33  corresponds with substantially all of footwear  10 , a cavity might be formed in midfoot region  12  of chamber  33  to accommodate an electrical or electronic device. 
     In a further example, as depicted in  FIG. 10D , a substantially circular chamber for use in various apparel, athletic equipment, or other household goods or industrial products, includes a first tensile structure  50   a  and a second tensile structure  50   b , first tensile structure  50   a  having a height greater than second tensile structure  50   b . Correspondingly, first window area  47   a  and second window area  48   a  have greater extents of outward protrusion than first window area  47   b  and second window area  48   b.    
     Additionally, In  FIGS. 10A-10B , first window area  47   a  may have a greater extent of outward protrusion than second window area  48   a , imparting an asymmetric shape to chamber  33 , which in footwear may correspond with an asymmetric medio-lateral shape. Similarly, first window area  47   b  may have a greater extent of outward protrusion than second window area  48   b , which may also impart an asymmetric shape to chamber  33 . In some configurations, however, first window area  47   a  may have a lesser extent of outward protrusion than second window area  48   a , or first window area  47   b  may have a lesser extent of outward protrusion than second window area  48   b , which may impart an alternate asymmetric shape to chamber  33 . 
     As depicted in  FIGS. 1-6C , first window area  47   b  has a greater extent of outward protrusion than second window area  48   b , and first window area  47   b  is located substantially opposite second window area  48   b  on chamber  33  in midfoot region  12  of footwear  10 . In other configurations, window areas located substantially opposite each other on chamber  33  and having different extents of outward protrusion may be located in other regions of footwear  10 . For example, as depicted in  FIG. 10E , first window area  47   a  has a lesser extent of outward protrusion than second window area  48   a , and first window area  47   a  is located substantially opposite second window area  48   a  in heel region  13  of chamber  33 . Similarly, first window area  47   c  has a lesser extent of outward protrusion than second window area  48   c , and first window area  47   c  is located substantially opposite second window area  48   c  in forefoot region  11  of chamber  33 . In various configurations, window areas located substantially opposite each other on chamber  33  may have differing extents of outward protrusion, and the window area with the greater extent of outward protrusion may be either on lateral side  14  of chamber  33  or on medial side  15  of chamber  33 . 
     Further Manufacturing Processes 
     Various suitable manufacturing processes may incorporate peripheral cavities, or peripheral indentations, having various inward extents, which may correspond with various extents of outward protrusion of window areas on chamber  33 . For example, peripheral regions  67  and  68  in  FIG. 11A  have a first inward extent, peripheral regions  67  and  68  in  FIG. 11B  have a second inward extent, and peripheral regions  67  and  68  in  FIG. 11C  have a third inward extent. In  FIGS. 11A-11C , the first inward extent is greater than the second inward extent, and the second inward extent is greater than the third inward extent. Correspondingly, window areas  47   b  and  48   b  in  FIG. 11A  have a first extent of outward protrusion, window areas  47   b  and  48   b  in  FIG. 11B  have a second extent of outward protrusion, and window areas  47   b  and  48   b  in  FIG. 11C  have a third extent of outward protrusion. In  FIGS. 11A-11C , the first extent of outward protrusion is greater than the second extent of outward protrusion, and the second extent of outward protrusion is greater than the third extent of outward protrusion. 
     As depicted in  FIGS. 1-9E , the extent of outward protrusion of window areas  47   b  and  48   b  corresponds with the inward extent of peripheral regions  67  and  68 . In other configurations, the extent of outward protrusion of various window areas may correspond with more than the inward extent of associated peripheral regions. For example, as depicted in  FIG. 11D , peripheral regions  67  and  68  have an inward extent similar to the third inward extent of peripheral regions  67  and  68  in  FIG. 11C . However, tensile structure  50   b  in  FIG. 11D  has a lesser medio-lateral extent through chamber  33  than tensile structure  50   b  in  11 C. In turn, window areas  47   b  and  48   b  in  FIG. 11D  have an extent of outward protrusion greater than window areas  47   b  and  48   b  in  FIG. 11C . 
     As depicted in  FIGS. 1-9E , the outward extent of window areas  47   b  and  48   b  corresponds with a depth of the inward extent of peripheral regions  67  and  68 . In other configurations, the outward extent of window areas may correspond with more than a depth of the inward extent of peripheral regions  67  and  68 . For example, as depicted in  FIG. 11E , the outward extent of first window area  47   b  corresponds with the inward extent of first peripheral region  67 , which has a lesser depth but a greater width than second peripheral region  68 . As an alternate example, as depicted in  FIG. 11F , the outward extent of first window area  47   b  corresponds with the inward extent of first peripheral region  67 , which has a greater depth but a lesser width than second peripheral region  68 . 
     As depicted in  FIG. 7-9E , a molding surface of first mold portion  61  is substantially flat. However, in other configurations, a molding surface of first mold portion  61  may not be flat. For example, as depicted in  FIG. 11G , the molding surface of first mold portion  61  includes cavity  69 , while peripheral regions  67  and  68  of second mold portion  62  have an inward extent similar to the second inward extent of  FIG. 11B . Accordingly, the extent of outward protrusion of window areas  47   b  and  48   b  depends upon the extent of cavity  69  in addition to the inward extent of peripheral regions  67  and  68  in second mold portion  62 . 
     Alternatively, as depicted in  FIG. 11H , peripheral regions  67  and  68  in first mold portion  62  have an inward extent similar to the third inward extent of  FIG. 11C , and second mold portion  62  also has peripheral regions  67  and  68  within cavity  69  which have inward extents similar to the third extent of  FIG. 11C . Accordingly, the extent of outward protrusion of first window area  47   b  depends upon the extent of first peripheral regions  67  in both first mold portion  61  and second mold portion  62 , and the extent of outward protrusion of second window area  48   b  depends upon the extent of second peripheral regions  68  in both first mold portion  61  and second mold portion  62 . That is, a portion of peripheral cavity  63  may be defined by peripheral regions  67  and  68  of second mold portion  62 , and another portion of peripheral cavity  63  may be defined by peripheral regions  67  and  68  of first mold portion  61 . Accordingly, an inward extent of peripheral cavity  63  may be an aggregate extent of first peripheral regions in mold portions  61  and  62 , or an aggregate extent of second peripheral regions in mold portions  61  and  62 . 
     As a further alternative, as depicted in  FIG. 111 , second peripheral region  68  has an inward extent similar to the inward extent of  FIGS. 9A-9E , as do both first peripheral region  67  in second mold portion  62  and first peripheral region  67  in first mold portion  61 . Accordingly, the extent of outward protrusion of second window area  48   b  of  FIG. 111  is similar to the extent of outward protrusion of second window area  48   b  of  FIGS. 9A-9E . In contrast, while the inward extent of first peripheral region  67  in second mold portion  61  of  FIG. 111  is less than the inward extent of first peripheral region  67  in second mold portion  61  of  FIGS. 9A-9E , the extent of outward protrusion of first window area  47   b  of  FIG. 111  may be qualitatively similar to the extent of outward protrusion of first window area  47   b  of  FIGS. 9A-9E . That is, the extent of outward protrusion of first window area  47   b  of  FIG. 111  may have a lateral spacing or an overall extent in cross-sectional area or in volume that is similar to or substantially the same as the extent of outward protrusion of first window area  47   b  of  FIGS. 9A-9E . Accordingly, as depicted in  FIG. 111 , the extent of outward protrusion of first window area  47   b  may be greater than the extent of outward protrusion of second window area  48   b , despite first peripheral region  67  of second mold portion  62  having similar or substantially the same inward extent as second peripheral region  68  of second mold portion  62 . 
     As depicted in  FIGS. 1-9E , midfoot region  12  of chamber  33  includes a tensile structure  50   b  comprising a textile tensile member the height of which is substantially the same at all parts. In other configurations, various regions of footwear  10 , such as midfoot region  12 , may contain tensile structures having other configurations. For example, as depicted in  FIG. 11J , a tensile structure in midfoot region  12  of chamber  33  includes two textile tensile members, each having a different height. In other configurations, tensile structures in any region or part of chamber  33  may include tensile members having substantially the same heights, and may include one, two, or more tensile members. In another example, as depicted in  FIG. 11K , a tensile structure in midfoot region  12  of chamber  33  includes a textile tensile structure having a contour, such that a height of the textile tensile structure is greater on lateral side  14  of chamber  33  than on medial side  15  of chamber  33 . In other configurations, tensile structures in any region or part of chamber  33  may include tensile members having any contour, such as an overall taper, a heel bevel, or a heel cup, for example. In a further example, as depicted in  FIG. 11L , a tensile structure in midfoot region  12  of chamber  33  includes a variety of tether elements, such as I-shaped tether elements  153   a , fluid-filled member  153   b , foam member  153   c , textile member  153   d , x-shaped member  153   e , or telescoping member  153   f . In other configurations, tensile structures in any region or part of chamber  33  may include any of a variety of tether elements, such as any of the tether elements disclosed in U.S. patent application Ser. No. 12/630,642 to Peyton and U.S. patent application Ser. No. 12/777,167 to Peyton. 
     Window areas of different extents of outward protrusion may be included in other fluid-filled chambers as well. For example, as depicted in  FIGS. 12 and 13 , first window areas  457   a - 457   d  and opposite second window areas  458   a - 458   d  have been included in fluid-filled chamber  433  along with other elements. Chamber  433  includes indented areas  446  and bonded regions  448 . Chamber  433  also includes tensile members  450   a - 450   e , whose heights may differ, which may in turn impart a contour to chamber  433 . Additionally, chamber  433  includes a window portion having both first window areas  457   a - 457   d  and opposite second window areas  458   a - 458   d , which may have different extents of outward protrusion, including a variation between a lateral side and a medial side of chamber  433 . 
     The invention is disclosed above and in the accompanying Figures with reference to a variety of configurations. The purpose served by the disclosure, however, is to provide an example of the various features and concepts related to the invention, not to limit the scope of the invention. One skilled in the relevant art will recognize that numerous variations and modifications may be made to the configurations described above without departing from the scope of the present invention, as defined by the appended claims.