Patent Description:
Footwear typically includes a sole structure configured to be located under a wearer's foot to space the foot away from the ground or floor surface. Polyurethane foam, rubber, or other resilient materials are often used in the sole structure to provide cushioning. Footwear bladders may be used in sole structures, may be inflated with fluid to a desired pressure or may be unpressurized, and may provide resilient cushioning and support.

<CIT> describes a sole structure for an article of footwear.

<CIT> describes a footwear bladder system.

The subject matter of the claimed invention is defined in the independent claims. Specific embodiments are defined in the dependent claims.

The present disclosure generally relates to cushioning elements that may be footwear bladders with multiple fluid-filled chambers having specific shapes, locations, and fluid pressures, which may include pressurized chambers (inflated above ambient pressure) or unpressurized chambers (at ambient pressure) that may provide cushioning and stability to the wearer. While the cushioning elements and bladders disclosed herein may be configured for all footwear sizes, the specific shapes, volumes, geometries, inflation pressures (or ambient pressure, such as if unpressurized) of the various chambers of the bladder, and whether the chambers are fluidly connected or fluidly isolated from one another as shown and described herein may be especially suitable for footwear sizes generally worn by toddlers and children of preschool and grade school age.

A sole structure for an article of footwear includes a bladder defining a fluid-filled peripheral chamber and a fluid-filled heel chamber fluidly isolated from the peripheral chamber. The peripheral chamber is configured as an elongated tube, and has a heel portion establishing a rear periphery of the bladder, a lateral arm portion extending from the heel portion and establishing a lateral periphery of the bladder, and a medial arm portion extending from the heel portion and establishing a medial periphery of the bladder. The bladder includes webbing connecting the heel chamber to the peripheral chamber, with the heel chamber disposed between the medial arm portion and the lateral arm portion and forward of the peripheral chamber in a heel region of the bladder. The lateral arm portion may have a terminal end in a forefoot region of the bladder, and the medial arm portion may have a terminal end rearward of the terminal end of the lateral arm portion.

The elevation of the peripheral chamber in the heel region of the bladder may be greater than the elevation of the heel chamber. As such, loading of the heel chamber may be secondary to loading of the peripheral chamber. The heel chamber may be configured to provide resilient deformation under dynamic loading, providing a cushioning function whether unpressurized or pressurized.

In some embodiments, the heel chamber is sealed and unpressurized and the peripheral chamber is sealed and unpressurized. As used herein, "unpressurized" means that a chamber is not inflated to a pressure above ambient pressure. A sealed, unpressurized chamber thus contains a gas such as air at ambient pressure. For example, if the bladder is molded by blow molding, the chambers may be unpressurized. In other embodiments, the chambers are pressurized. For example, in some embodiments, the peripheral chamber is sealed and retains fluid at a first fluid pressure, and the heel chamber is sealed and retains fluid at a second fluid pressure different than the first fluid pressure. In an example, the second fluid pressure is lower than the first fluid pressure. For example, in an embodiment in which the bladder is molded by thermoforming, the first and second fluid pressures may be obtained by inflating each the respective chamber to the desired fluid pressure before sealing the chamber to retain the desired fluid pressure.

The bladder may include a perimeter flange extending along the lateral periphery, the rear periphery, and the medial periphery of the bladder. The perimeter flange may be disposed nearer to a lowest extremity of the peripheral chamber at a ground-facing surface of the peripheral chamber than to a highest extremity of the peripheral chamber at a foot-facing surface of the peripheral chamber in the heel region of the bladder along the lateral periphery, the rear periphery, and the medial periphery. This placement of the perimeter flange results in a bladder that is wider in the transverse direction toward the bottom than toward the top, which provides greater stability than a narrower bladder of the same length.

The bladder may be configured so that an inner wall of the peripheral chamber may be steeper than an outer wall of the peripheral chamber, at least directly outward of the heel chamber. The relatively steep inner wall may provide increased stiffness and stability to the peripheral chamber, especially in an unpressurized embodiment, and greater space for the heel chamber to resiliently deform under a dynamic load.

In addition to the peripheral chamber and the heel chamber, the bladder defines at least two additional fluid-filled chambers fluidly isolated from the peripheral chamber. The at least two additional fluid-filled chambers include a rear midfoot chamber and a front midfoot chamber. The at least two additional fluid-filled chambers may include three additional fluid-filled chambers, which may be the rear midfoot chamber, the front midfoot chamber, and a forefoot chamber. In some embodiments, the peripheral chamber, the heel chamber, the rear midfoot chamber, the front midfoot chamber, and the forefoot chamber are the only fluid-filled chambers of the bladder. The rear midfoot chamber is disposed between and connected to the heel chamber and the front midfoot chamber by the webbing. The rear midfoot chamber and the front midfoot chamber are connected to the lateral arm portion and to the medial arm portion by the webbing. The forefoot chamber may be disposed forward of the front midfoot chamber and may be connected to only the front midfoot chamber and the lateral arm portion by the webbing.

In another implementation, the at least two additional fluid-filled chambers may be only two additional chambers, which are the rear midfoot chamber and the front midfoot chamber. In such an embodiment, the peripheral chamber, the heel chamber, the rear midfoot chamber, and the front midfoot chamber are the only fluid-filled chambers of the bladder. The rear midfoot chamber is disposed between and connected to the heel chamber and the front midfoot chamber by the webbing. The rear midfoot chamber and the front midfoot chamber are connected to the lateral arm portion and to the medial arm portion by the webbing.

The bladder includes a groove extending between the medial arm portion and the front midfoot chamber, between the medial arm portion and the rear midfoot chamber, between a rear of the rear midfoot chamber and the heel chamber, between the rear midfoot chamber and the lateral arm portion, and between the front midfoot chamber and the lateral arm portion. For example, the groove may be molded into the bladder. The groove may serve as a guide at which the bladder may be optionally trimmed to remove the at least two additional chambers, such as the rear midfoot chamber, the front midfoot chamber, and, where included, the forefoot chamber. The groove thus enables efficiencies in manufacturing, as two different bladder configurations can ultimately be obtained from one mold.

The chambers of the bladder may be shaped and configured specifically to correspond with expected loading patterns of a wearer's foot. In an example, a periphery of the rear midfoot chamber may be a convex, irregular quadrilateral with rounded corners, a rear side, a front side longer than the rear side, a medial side, and a lateral side longer than the medial side. A periphery of the front midfoot chamber may be a convex, irregular quadrilateral with rounded corners, a rear side, a front side longer than the rear side, a medial side, and a lateral side shorter than the medial side. Configuring the chambers with corners may limit the tendency of the chamber to balloon in comparison to a rounded chamber, resulting in a more uniform underfoot feel.

The rear side of the front midfoot chamber may be parallel with the front side of the rear midfoot chamber. A periphery of the forefoot chamber may include a lateral side extending parallel with the lateral arm portion, a rear side disposed forward of the terminal end of the medial arm portion and extending forwardly from a lateral extent to a medial extent, and a front side extending rearwardly from a lateral extent to a medial extent. A forward edge of the bladder may extend along the front side of the front midfoot chamber and along the front side of the forefoot chamber. The forward edge of the bladder may be rearward of a line tangent to the terminal end of the lateral arm portion and the terminal end of the medial arm portion. A majority of the forefoot chamber may be disposed between the lateral arm portion of the peripheral chamber and a longitudinal midline of the bladder. The lateral side of the forefoot chamber, the lateral side of the front midfoot chamber, and the lateral side of the rear midfoot chamber may be equidistant from the lateral arm portion. The medial side of the front midfoot chamber and the medial side of the rear midfoot chamber may be equidistant from the medial arm portion.

The various chambers of the bladder may be fluidly isolated or in fluid communication with one another, offering various combinations of fluid pressures (at or above ambient pressure) in the chambers to provide different corresponding cushioning profiles. For example, a first channel may extend between and fluidly connect the forefoot chamber and the front midfoot chamber, and/or a second channel may extend between and fluidly connect the front midfoot chamber and the rear midfoot chamber, and/or a third channel may extend between and fluidly connect the rear midfoot chamber and the heel chamber. Each of the forefoot chamber, the front midfoot chamber, and the rear midfoot chamber may be fluidly isolated from one another and from the heel chamber, for example, if these channels are sealed. Alternatively, one or more of the heel chamber, the forefoot chamber, the front midfoot chamber, and the rear midfoot chamber may be in fluid communication with one another by not sealing one or more of the channels. The bladder may include a single fill port extending from the front side of the front midfoot chamber to be used during inflation of the bladder (or blow molding of the bladder in blow molded embodiments), or the bladder may include more than one fill port.

When assembled in an article of footwear, an outsole may underlie the bladder, a midsole layer, such as a foam layer, may overlie the bladder, and a footwear upper may overlie the bladder and be secured to the bladder or to another component of the sole structure, such as the midsole layer. In some embodiments, the midsole layer may overlie the bladder between the upper and the bladder.

An exterior surface of the bladder may be exposed between the upper and the outsole at the medial arm portion, the lateral arm portion, and the heel portion both for aesthetic purposes and to allow the sides of the bladder to elastically deform. In embodiments with an overlying midsole layer, the exterior surface of the bladder may be exposed between the midsole layer and the outsole at the medial arm portion, the lateral arm portion, and the heel portion. For example, the entire exterior surface of the bladder may be exposed between the midsole layer and the outsole at the medial arm portion, the lateral arm portion, and the heel portion.

In some embodiments, the bladder may be blow molded and the various chambers unpressurized. In other embodiments, the bladder may be thermoformed and the various chambers pressurized to different relative pressures. The geometry and/or volume of the various chambers may be different in a blow molded bladder than in a thermoformed bladder to account for the particular advantages and limitations of each forming process.

Within the scope of the disclosure, an article of footwear may incorporate any one of the sole structures including any one of the bladders disclosed herein.

Referring to the drawings, wherein like reference numbers refer to like components throughout the views, <FIG> is a top view of a first embodiment of a bladder <NUM>. <FIG> is a bottom view of the bladder <NUM>. The bladder <NUM> is configured to be used as a component of a sole structure <NUM> of an article of footwear <NUM>, as discussed with respect to <FIG>. The bladder <NUM> includes a polymeric material that is configured to define a peripheral chamber <NUM> and a heel chamber <NUM>. As used herein, a chamber is a fluid-filled cavity, and, as discussed herein, the bladder <NUM> is configured so that the chambers <NUM>, <NUM> may be filled with gas (such as air or nitrogen) and sealed to retain the gas at a predetermined pressure, which may be ambient pressure or a pressure above ambient.

The peripheral chamber <NUM> is configured as an elongated tube, and has a heel portion 16A, a lateral arm portion 16B, and a medial arm portion 16C. The heel portion 16A establishes a rear periphery 20A of the bladder <NUM>. The lateral arm portion 16B extends from the heel portion 16A and establishes a lateral periphery 20B of the bladder <NUM>. The medial arm portion 16C extends from the heel portion 16A and establishes a medial periphery 20C of the bladder <NUM>. The bladder <NUM> also includes webbing 16D connecting the heel chamber <NUM> to the peripheral chamber <NUM>, and flanges 16E and <NUM> discussed herein.

The bladder <NUM> has a medial side <NUM>, a lateral side <NUM>, a foot-facing surface <NUM>, and a ground-facing surface <NUM> opposite from the foot-facing surface <NUM>. The foot-facing surface <NUM> may also be referred to as a first side or top side, and the ground-facing surface <NUM> may be referred to as a second side or bottom side. The foot-facing surface <NUM> generally faces upward when the bladder <NUM> is assembled in the article of footwear <NUM>, and the ground-facing surface <NUM> generally faces downward. The medial side <NUM> and the lateral side <NUM> also describe the medial side and the lateral side, respectively, of the sole structure <NUM> and the article of footwear <NUM> in <FIG>.

The bladder <NUM> includes a forefoot region <NUM>, a midfoot region <NUM>, and a heel region <NUM>. The heel region <NUM> generally corresponds with rear portions of a human wearer's foot, including the calcaneus bone, with the foot corresponding in size to the article of footwear <NUM>. The forefoot region <NUM> generally includes portions of the bladder <NUM> corresponding with the toes and the joints connecting the metatarsals with the phalanges of the foot. The midfoot region <NUM> generally corresponds with an arch area of the foot, including the navicular j oint, and extends from the forefoot region <NUM> to the heel region <NUM>. The bladder <NUM> and the article of footwear <NUM> are shown configured for a left foot. However, the description of the bladder <NUM> applies equally to a mirror-image bladder configured for a right foot.

The heel chamber <NUM> is disposed between the medial arm portion 16C and the lateral arm portion 16B, forward of the heel portion 16A of the peripheral chamber <NUM>, and mainly in the heel region <NUM> of the bladder <NUM>. The heel chamber <NUM> and the peripheral chamber <NUM> are the only fluid-filled chambers of the bladder <NUM>. The lateral arm portion 16B has a terminal end <NUM> in the forefoot region <NUM>, and the medial arm portion 16B has a terminal end <NUM> rearward of the terminal end <NUM>. The terminal end <NUM> is the foremost extent of the bladder <NUM> and is also the foremost extent of the lateral arm portion 16B. The terminal end <NUM> is the foremost extent of the medial arm portion 16C. The terminal end <NUM> may be in the midfoot region <NUM> of the bladder <NUM>, or may be in a rear portion of the forefoot region <NUM>. The webbing 16D terminates rearward of the forefoot region <NUM>. Accordingly, the forefoot region <NUM> includes only the lateral arm portion 16B. No part of the bladder <NUM> is disposed on a medial side of a longitudinal midline L of the bladder <NUM> in the forefoot region <NUM>. The bladder <NUM> is thus characterized by an absence of a medial forefoot portion, due to the location of the terminal end <NUM> and the absence of webbing in the forefoot region at the medial side <NUM>.

In various embodiments, the bladder <NUM> and the other bladder embodiments shown and described herein may be blow molded, welded by radiofrequency welding, or thermoformed in a mold. In the embodiment shown, the bladder <NUM> is thermoformed from two sheets, including a first polymeric sheet <NUM> and a second polymeric sheet <NUM>. The first polymeric sheet <NUM> may be referred to as a top sheet as it establishes the foot-facing surface <NUM>. The second polymeric sheet <NUM> may be referred to as the bottom sheet as it establishes the ground-facing surface <NUM>. As best shown in <FIG>, the first polymeric sheet <NUM> is secured to the second polymeric sheet <NUM> at a perimeter flange <NUM> to enclose the peripheral chamber <NUM>. A transversely inward side of the peripheral chamber <NUM> and the heel chamber <NUM> are enclosed by the webbing 16D as shown at an edge <NUM> of the webbing 16D in <FIG>. The webbing 16D includes portions of the bladder <NUM> where the first polymeric sheet <NUM> is bonded to the second polymeric sheet <NUM> transversely inward of the peripheral chamber <NUM>. The bladder <NUM> may be trimmed at the portions of the webbing 16D extending along the inner sides of the arm portions 16B, 16C and at the edge <NUM>, so that the only a flange 16E remains at these portions. When the polymeric sheets <NUM>, <NUM> are secured together at the perimeter flange <NUM> and at the webbing 16D, and one or more fill ports described herein are sealed, the polymeric bladder <NUM> is sealed, and the first polymeric sheet <NUM> and the second polymeric sheet <NUM> retain a fluid in the peripheral chamber <NUM> and the heel chamber <NUM>. As used herein, a "fluid" filling the chambers <NUM>, <NUM> may be a gas, such as air, nitrogen, another gas, or a combination thereof.

Accordingly, the first polymeric sheet <NUM> and the second polymeric sheet <NUM> define the peripheral chamber <NUM>, the heel chamber <NUM>, the webbing 16D, the flange 16E, and the perimeter flange <NUM> at the medial periphery 20C, the lateral periphery 20B, and the rear periphery 20A, and any remaining flange 16E, and the first polymeric sheet <NUM> and the second polymeric sheet <NUM> are bonded to one another at the webbing 16D, the perimeter flange <NUM>, and the flange 16E and separated from one another at the heel chamber <NUM> and the peripheral chamber <NUM>.

The first and second polymeric sheets <NUM>, <NUM> can be a variety of polymeric materials that can resiliently retain a fluid such as nitrogen, air, or another gas. Examples of polymeric materials for the first and second polymeric sheets <NUM>, <NUM> include thermoplastic urethane, polyurethane, polyester, polyester polyurethane, and polyether polyurethane. Moreover, the first and second polymeric sheets <NUM>, <NUM> can each be formed of layers of different materials including polymeric materials. In one embodiment, each of the first and second polymeric sheets <NUM>, <NUM> is formed from thin films having one or more thermoplastic polyurethane layers with one or more barrier layers of a copolymer of ethylene and vinyl alcohol (EVOH) that is impermeable to the pressurized fluid contained therein such as a flexible microlayer membrane that includes alternating layers of a gas barrier material and an elastomeric material, as disclosed in <CIT> and <CIT> Alternatively, the layers may include ethylene-vinyl alcohol copolymer, thermoplastic polyurethane, and a regrind material of the ethylene-vinyl alcohol copolymer and thermoplastic polyurethane. Additional suitable materials for the first and second polymeric sheets <NUM>, <NUM> are disclosed in <CIT> and <CIT>. Further suitable materials for the first and second polymeric sheets <NUM>, <NUM> include thermoplastic films containing a crystalline material, as disclosed in <CIT> and <CIT>, and polyurethane including a polyester polyol, as disclosed in <CIT>, <CIT>, and <CIT> In selecting materials for the bladder <NUM>, engineering properties such as tensile strength, stretch properties, fatigue characteristics, dynamic modulus, and loss tangent can be considered. For example, the thicknesses of the first and second polymeric sheets <NUM>, <NUM> used to form the bladder <NUM> can be selected to provide these characteristics.

As best shown in <FIG>, the bladder <NUM> has two separate fill ports 50A and 50B. The fill ports 50A, 50B are initially unsealed tubular channels between the first and second polymeric sheets <NUM>, <NUM> that are subsequently sealed after the chambers <NUM>, <NUM> are filled with fluid (e.g., by inflation). The fill port 50A communicates with the peripheral chamber <NUM> and is used during manufacturing of the bladder <NUM> to access the peripheral chamber <NUM> and, in a pressurized embodiment, to inflate and fill it with fluid to a predetermined pressure. The fill port 50B communicates with the heel chamber <NUM> and is used during manufacturing of the bladder <NUM> to access the heel chamber <NUM> and, in a pressurized embodiment, to inflate and fill it with fluid to a predetermined pressure, which may be the same or a different pressure than that of the peripheral chamber <NUM>. Alternatively, the bladder <NUM> could be configured with only a single fill port (either fill port 50A or fill port 50B) and with a channel extending between and initially fluidly connecting the chambers <NUM> and <NUM>, but sealed during the inflation process to fluidly isolate the chambers <NUM>, <NUM> from one another and enable two different pressures in the chambers <NUM>, <NUM>.

In <FIG>, the fill ports 50A, 50B are shown sealed so that the filled chambers <NUM>, <NUM> retain the fluid at the predetermined pressure(s). The peripheral chamber <NUM> and the heel chamber <NUM> are fluidly isolated from one another in the bladder <NUM>. Stated differently, there are no open (unsealed) channels crossing the webbing 16D to connect the chambers <NUM>, <NUM>. Accordingly, the chambers <NUM>, <NUM> may be filled with and retain fluid at different predetermined pressures. In the embodiment of the bladder <NUM> shown in <FIG>, for example, the peripheral chamber <NUM> is sealed and retains fluid at a first fluid pressure and the heel chamber <NUM> is sealed and retains fluid at a second fluid pressure different than the first fluid pressure. In one non-limiting example, the second fluid pressure in the heel chamber <NUM> may be ambient pressure or a pressure up to <NUM> pounds per square inch more than ambient pressure where a pound per square inch is equal to <NUM> Pa, while the first fluid pressure in the peripheral chamber <NUM> may be more than <NUM> pounds per square inch above ambient pressure, up to <NUM> pounds per square inch above ambient pressure. In a specific example, the peripheral chamber <NUM> may be inflated to and sealed to retain fluid at <NUM> pounds per square inch above ambient pressure, and the heel chamber <NUM> may be inflated to and sealed to retain fluid at <NUM> pounds per square inch above ambient pressure. In another specific example, the peripheral chamber <NUM> may be inflated to and sealed to retain fluid at <NUM> pounds per square inch above ambient pressure, and the heel chamber <NUM> may be inflated to and sealed to retain fluid at <NUM> pounds per square inch above ambient pressure. The second fluid pressure is less than the first fluid pressure in the embodiment shown. This enables the relatively high pressure peripheral chamber <NUM> to be relatively firm, providing good peripheral support, such as at the medial and lateral sides <NUM>, <NUM> while also providing softer cushioning in the center of the heel region <NUM> under the wearer's heel at the relatively low pressure heel chamber <NUM>.

Referring to <FIG>, the article of footwear <NUM> is shown with an upper <NUM> secured to the sole structure <NUM>. In addition to the bladder <NUM>, the sole structure <NUM> includes an outsole <NUM> underlying the bladder <NUM>. For example, the outsole <NUM> may be secured to the ground-facing surface <NUM> of <FIG> and the upper <NUM> may be secured to the foot-facing surface <NUM>. Alternatively, one or more sole layers, such as midsole layers of foam or another material may be disposed between the upper <NUM> and the bladder <NUM> and/or between the bladder <NUM> and the outsole <NUM>.

<FIG> show a midsole layer <NUM> disposed in the forefoot region <NUM> extending rearward to the terminal ends <NUM>, <NUM>. The midsole layer <NUM> may also extend between the arm portions 16B, 16C back to the edge <NUM> of the webbing 16D shown just forward of the heel chamber <NUM> in <FIG>, and may further extend over the foot-facing surface <NUM> of the bladder <NUM> rearward of the edge <NUM> in some embodiments. The midsole layer <NUM> may be, for example, a foam material and can have a different compressive stiffness than the compressive stiffnesses of the inflated heel chamber <NUM> and peripheral chamber <NUM>.

The bladder <NUM> is visible at the lateral side <NUM> of the footwear <NUM>, as shown in <FIG>, at the medial side <NUM> as shown in <FIG>, and at the rear of the heel region <NUM> as is evident in both views. This visibility is possible because the upper <NUM> and the outsole <NUM> are arranged so that an exterior surface <NUM> of the bladder <NUM> (also referred to herein as an exterior side surface <NUM>) is exposed between the upper <NUM> and the outsole <NUM> at the medial arm portion 16C, the lateral arm portion 16B, and the heel portion 16A.

<FIG> is a lateral side view of the bladder <NUM> of <FIG> showing the lateral arm portion 16B extending from the heel portion 16A to the terminal end <NUM>. <FIG> is a medial side view of the bladder <NUM>, showing the medial arm portion 16C extending from the heel portion 16A to the terminal end <NUM>, which is rearward of the terminal end <NUM>. <FIG> is a rear view of the bladder <NUM> showing the rear of the heel portion 16A. The perimeter flange <NUM> connects the first polymeric sheet <NUM> and the second polymeric sheet <NUM> and extends around the entire outer exterior, as is evident in <FIG>.

With reference to <FIG>, the terminal end <NUM> is disposed further forward in the forefoot region <NUM> than the medial end <NUM>. This longer length of the lateral arm portion 16B in comparison to the medial arm portion 16C lends stability to the bladder <NUM> and allows for more visibility of the bladder <NUM>. The medial end <NUM> being further rearward allows for more flexibility, as the bladder <NUM> will bend under the metatarsal heads of the foot during dorsiflexion. The midsole layer <NUM> is disposed under the metatarsal heads and may be more flexible than the arm portions 16B, 16C. With the positioning of the terminal end <NUM> and the terminal end <NUM> rearward of the foremost extent of the sole structure <NUM> of <FIG>, and the absence of the bladder <NUM> in the forefoot region at the medial side <NUM>, the bladder <NUM> may be referred to as a three-quarter length bladder. The additional bladders <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> disclosed herein are also three-quarter length bladders.

It is apparent in <FIG> that the lateral arm portion 16B and the medial arm portion 16C of the peripheral chamber <NUM> taper in height from the heel portion 16A to the respective terminal ends <NUM>, <NUM>, and that the peripheral chamber <NUM> is greatest in height at the heel portion 16A. <FIG> is a front view of the bladder <NUM> and shows both the portions 16A, 16B, and 16C of the peripheral chamber <NUM> and also shows the heel chamber <NUM>. <FIG> is a cross-sectional view of the bladder <NUM> taken at lines <NUM>-<NUM> in <FIG>. It is evident from <FIG> that the maximum elevation E1 of the heel chamber <NUM> is less than the elevation E2 of the heel portion 16A of the peripheral chamber <NUM> and is less than the elevation E3 of the medial arm portion 16C and the elevation E4 of the lateral arm portion 16B directly transversely laterally outward of the heel chamber <NUM>. The elevations E2, E3, and E4 may be taken at any location along the heel portion 16A, the lateral arm portion 16B, and the medial arm portion 16C, respectively, that is directly outward of and bordering the heel chamber <NUM>. The elevations E1, E2, E3, E4 are when the bladder <NUM> is in a static state (not under dynamic loading). Due to this height differential between the heel chamber <NUM> and the peripheral chamber <NUM>, as well as the tapering height of the peripheral chamber <NUM> from the heel portion 16A to the terminal ends <NUM>, <NUM>, during wear, the article of footwear <NUM> will typically first make contact with the ground at the heel region <NUM>, and the much taller peripheral chamber <NUM> will be loaded before the heel chamber <NUM>. In an embodiment in which the heel chamber <NUM> is at a lower pressure than the peripheral chamber <NUM>, as the foot loads the heel chamber <NUM>, it may resiliently deform under loading, providing cushioning under the calcaneus bone.

<FIG> is a cross-sectional view of the bladder <NUM> taken at lines <NUM>-<NUM> in <FIG>, and <FIG> is a cross-sectional view of the bladder <NUM> taken at lines <NUM>-<NUM> in <FIG>. The perimeter flange <NUM> is higher at the exterior side surface <NUM> of the bladder <NUM> than at transversely inward side surfaces of the arm portions 16B, 16C, causing the first polymeric sheet <NUM> to slope downward and transversely inward as shown to better wrap around and support the periphery of the foot.

<FIG> show an alternative embodiment of a bladder <NUM> that has many of the same features as discussed with respect to the bladder <NUM>, which features are referred to with like reference numbers. As shown, the bladder <NUM> is thermoformed from first and second polymeric sheets <NUM>, <NUM>. The bladder <NUM> can be used in the article of footwear <NUM> of <FIG> instead of the bladder <NUM>, with the outsole <NUM> secured to the ground-facing surface <NUM> shown in <FIG> and the upper <NUM> secured to the foot-facing surface <NUM> shown in <FIG>, or with one or more sole layers, such as midsole layers of foam or another material disposed between the upper <NUM> and the bladder <NUM> and/or between the bladder <NUM> and the outsole <NUM>. A midsole layer like midsole layer <NUM> may be disposed in the forefoot region <NUM> extending rearward to the terminal ends <NUM>, <NUM> and the edge <NUM> of the webbing 16D shown in <FIG> and <FIG>, and may further extend over the foot-facing surface <NUM> of the bladder <NUM> and even rearward of the edge <NUM> in some embodiments. The midsole layer <NUM> may be, for example, a foam material having a different compressive stiffness than the compressive stiffness of the inflated forefoot chamber <NUM>. For example, the foam may be softer for providing cushioning under the metatarsophalangeal joint.

<FIG> shows the top view of the bladder <NUM>, including the peripheral chamber <NUM> and the heel chamber <NUM>, and the foot-facing surface <NUM> defined by the first polymeric sheet <NUM>. <FIG> shows the bottom view of the bladder <NUM> with the ground-facing surface <NUM>. The bladder <NUM> defines three additional chambers <NUM>, <NUM>, and <NUM> that are fluidly isolated from the peripheral chamber <NUM>. The three additional chambers include a rear midfoot chamber <NUM>, a front midfoot chamber <NUM>, and a forefoot chamber <NUM>. The peripheral chamber <NUM>, the heel chamber <NUM>, the rear midfoot chamber <NUM>, the front midfoot chamber <NUM>, and the forefoot chamber <NUM> are the only fluid-filled chambers of the bladder <NUM>. The rear midfoot chamber <NUM> and the front midfoot chamber <NUM> are disposed in the midfoot region <NUM>. The rear midfoot chamber <NUM> is disposed between and connected to the heel chamber <NUM> and the front midfoot chamber <NUM> by the webbing 16D formed by the bonded portions of the first polymeric sheet <NUM> and the second polymeric sheet <NUM>. The rear midfoot chamber <NUM> and the front midfoot chamber <NUM> are connected to the lateral arm portion 16B and the medial arm portion 16C by the webbing 16D. The forefoot chamber <NUM> is disposed forward of the front midfoot chamber <NUM> and is disposed in the forefoot region <NUM>. The forefoot chamber <NUM> is connected to only the front midfoot chamber <NUM> and to the lateral arm portion 16B by the webbing 16D. Accordingly, unlike the bladder <NUM>, the bladder <NUM> has at least one fluid-filled chamber transversely inward of the peripheral chamber <NUM> in each of the heel region <NUM>, the midfoot region <NUM>, and the forefoot region <NUM>. Like bladder <NUM>, the bladder <NUM> is characterized by an absence of a medial forefoot portion.

In addition to the peripheral chamber <NUM> and the heel chamber <NUM>, the chambers <NUM>, <NUM>, and <NUM> are shaped and positioned to support how a foot typically loads an underlying sole structure (e.g., corresponding with expected loading patterns of a wearer's foot) and to comfortably underlie the foot. Like the heel chamber <NUM>, the chambers <NUM>, <NUM>, and <NUM> are lower in elevation than the peripheral chamber <NUM>. Additionally, the chambers <NUM>, <NUM>, and <NUM> each include multiple corners <NUM> and relatively straight sides between adjacent corners <NUM>. In comparison to a more rounded perimeter, the polygon-shaped perimeter of each chamber <NUM>, <NUM>, and <NUM> helps to maintain a relatively low elevation of the chambers <NUM>, <NUM>, <NUM>, preventing a ballooning that could otherwise occur during inflation in a pressurized version. This helps to maintain a relatively flat top surface of each chamber <NUM>, <NUM>, and <NUM>, providing greater comfort under foot and avoiding pressure points.

For example, a periphery <NUM> of the rear midfoot chamber <NUM> is a convex, irregular quadrilateral with rounded corners <NUM>, a rear side <NUM>, a front side <NUM> longer than the rear side <NUM>, a medial side <NUM>, and a lateral side <NUM> longer than the medial side <NUM>. A periphery <NUM> of the front midfoot chamber <NUM> is a convex, irregular quadrilateral with rounded corners <NUM>, a rear side <NUM>, a front side <NUM> longer than the rear side <NUM>, a medial side <NUM>, and a lateral side <NUM> shorter than the medial side <NUM>. Additionally, the rear side <NUM> of the front midfoot chamber <NUM> is parallel with the front side <NUM> of the rear midfoot chamber <NUM>. A periphery <NUM> of the forefoot chamber <NUM> includes rounded corners <NUM>, a lateral side <NUM> extending parallel with the lateral arm portion 16B, a rear side <NUM> disposed forward of the terminal end <NUM> of the medial arm portion 16C and extending forwardly from a lateral extent 80A to a medial extent 80B, and a front side <NUM> extending rearwardly from a lateral extent 81A to a medial extent 81B. A majority of the forefoot chamber <NUM> is disposed between the lateral arm portion 16B of the peripheral chamber <NUM> and the longitudinal midline L of the bladder <NUM>.

By configuring the chambers <NUM>, <NUM>, <NUM> with corners <NUM> and relatively straight sides of adjacent chambers (adjacent chambers <NUM> and <NUM>, and adjacent chambers <NUM> and <NUM>) generally parallel with one another, in addition to preventing excessive ballooning of the chambers <NUM>, <NUM>, and <NUM> in the vertical direction, as discussed above, a maximum amount of space in the longitudinal and transverse directions between the lateral arm portion 16B and the medial arm portion 16C can be occupied by the chambers <NUM>, <NUM>, and <NUM> to enable the chambers <NUM>, <NUM>, and <NUM> to underlie more of the foot to maximize the cushioning and support benefits provided by the chambers <NUM>, <NUM>, <NUM>.

The forward edge <NUM> of the bladder <NUM> extends along the front side <NUM> of the front midfoot chamber <NUM> and along the front side <NUM> of the forefoot chamber <NUM>. The forward edge <NUM> may be a flange created by the webbing 16D that may be trimmed just forward of the front sides <NUM>, <NUM>. The forward edge <NUM> of the bladder <NUM> is rearward of a line L1 (shown in phantom) that is tangent to the terminal end <NUM> of the lateral arm portion 16B and to the terminal end <NUM> of the medial arm portion 16C. With this configuration, the bladder <NUM> is characterized by an absence of a medial forefoot portion.

As shown in <FIG>, the lateral side <NUM> of the forefoot chamber <NUM>, the lateral side <NUM> of the front midfoot chamber <NUM>, and the lateral side <NUM> of the rear midfoot chamber <NUM> are equidistant from the lateral arm portion 16B. Stated differently, the width W1 of the portion of the webbing 16D between the lateral arm portion 16B and the respective lateral sides <NUM>, <NUM>, and <NUM> is constant. Similarly, the medial side <NUM> of the front midfoot chamber <NUM> and the medial side <NUM> of the rear midfoot chamber <NUM> are equidistant from the medial arm portion 16C as the width W2 of the portion of webbing 16D between the medial arm portion 16C and the respective medial sides <NUM> and <NUM> is constant. The width W1 of the webbing 16D along the respective lateral sides <NUM>, <NUM>, and <NUM> is shown as equal to the width W2 of the webbing 16D along the respective medial sides <NUM> and <NUM>. The webbing 16D may have the same width W1 between the peripheral chamber <NUM> and the heel chamber <NUM> as well. Stated differently, each of the chambers <NUM>, <NUM>, and <NUM> may be centered between the arms portions 16B and 16C. The widths W1 and W2 can be selected to be sufficiently wide to enable the chambers <NUM>, <NUM>, <NUM>, and <NUM> to deform outward in the X-Y plane (e.g., in the transverse and longitudinal directions) under loading without interfering with the higher pressure peripheral chamber <NUM> while still enabling a maximum amount of space in the longitudinal and transverse directions between the lateral arm portion 16B and the medial arm portion 16C to be occupied by the chambers <NUM>, <NUM>, and <NUM> to enable the chambers <NUM>, <NUM>, and <NUM> to underlie more of the foot to maximize the cushioning and support benefits provided by the chambers <NUM>, <NUM>, <NUM>.

The bladder <NUM> includes only a single fill port <NUM> extending from the front side <NUM> of the front midfoot chamber <NUM>. The fill port <NUM> has been sealed in <FIG> after inflating the bladder <NUM>, as shown by weld <NUM>, and may be trimmed to a shorter length than shown in <FIG>. The various chambers of the bladder <NUM> may be filled to different pressures using only the single fill port <NUM> due to channels that fluidly connect adjacent chambers, and any or all of the channels may be sealed following inflation to isolate adjacent chambers connected by the channel(s). More specifically, referring to <FIG>, the bladder <NUM> includes a first channel <NUM> extending between and fluidly connecting the forefoot chamber <NUM> and the front midfoot chamber <NUM>, a second channel <NUM> extending between and fluidly connecting the front midfoot chamber <NUM> and the rear midfoot chamber <NUM>, and a third channel <NUM> extending between and fluidly connecting the rear midfoot chamber <NUM> and the heel chamber <NUM>. Additionally, a sealed channel <NUM> (the seal indicated by the weld <NUM>) extends between the front midfoot chamber <NUM> and the peripheral chamber <NUM>. The channel <NUM> fluidly connected the front midfoot chamber <NUM> and the peripheral chamber <NUM> prior to sealing the channel <NUM> at the weld <NUM>. In one example, the channels <NUM>, <NUM>, <NUM>, and <NUM> may be formed by disposing anti-weld material between the polymeric sheets <NUM>, <NUM> to prevent sealing of the sheets <NUM>, <NUM> to one another at the channels during thermoforming. One or more of the channels, such as channel <NUM>, may be subsequently sealed by a heat weld <NUM>. In the bladder <NUM>, the channels <NUM>, <NUM>, and <NUM> are not sealed so that the forefoot chamber <NUM>, the front midfoot chamber <NUM>, and the rear midfoot chamber <NUM> are in fluid communication with one another as well as with the heel chamber <NUM>, and each of the forefoot chamber <NUM>, the front midfoot chamber <NUM>, the rear midfoot chamber <NUM>, and the heel chamber <NUM> are fluidly isolated from the peripheral chamber <NUM>.

The peripheral chamber <NUM> may be inflated to a first fluid pressure that is the relatively highest pressure of the chambers by, for example, initially filling it to a predetermined, relatively high pressure, sealing the channel <NUM>, and filling or releasing fluid from the fill port <NUM> until a predetermined pressure is achieved in the remaining chambers <NUM>, <NUM>, <NUM>, and <NUM>. In the embodiment shown, the channels <NUM>, <NUM>, and <NUM> are not sealed, so that the chambers <NUM>, <NUM>, <NUM>, and <NUM> are at the same second fluid pressure, at least when in a static state. In one non-limiting example, the second fluid pressure in the chambers <NUM>, <NUM>, <NUM>, and <NUM> may be ambient pressure (if not inflated) or a pressure up to <NUM> pounds per square inch more than ambient pressure, while the first fluid pressure in the peripheral chamber <NUM> may be more than <NUM> pounds per square inch above ambient pressure, up to <NUM> pounds per square inch above ambient pressure. In a specific example, the peripheral chamber <NUM> may be inflated to and sealed to retain fluid at <NUM> pounds per square inch above ambient pressure, and the chambers <NUM>, <NUM>, <NUM>, and <NUM> may be inflated to and sealed to retain fluid at <NUM> pounds per square inch above ambient pressure. In another specific example, the peripheral chamber <NUM> may be inflated to and sealed to retain fluid at <NUM> pounds per square inch above ambient pressure, and the heel chamber <NUM> may be inflated to and sealed to retain fluid at <NUM> pounds per square inch above ambient pressure.

The fluid communication between the chambers <NUM>, <NUM>, <NUM>, and <NUM> by the unsealed channels <NUM>, <NUM>, and <NUM> allows the fluid to be displaced from one chamber to the next during dynamic loading. For example, during a forward stride, fluid may be displaced from the heel chamber <NUM> to the chambers <NUM>, <NUM>, and <NUM> forward of the heel chamber <NUM>, increasing the pressure in the chambers <NUM>, <NUM>, <NUM> and providing increased compressive stiffness. In another alternative, any or all of the channels <NUM>, <NUM>, and/or <NUM> could also be sealed after a predetermined pressure is achieved when inflating the chambers <NUM>, <NUM>, and <NUM>, respectively. The channels <NUM>, <NUM>, and <NUM> are disposed at the bottom side (e.g., at the ground-facing surface <NUM>) of the bladder <NUM>, and are formed mainly by the second polymeric sheet <NUM>, so that they do not affect the contours of the foot-facing surface <NUM>, are therefore not felt by the wearer, and do not interfere with flexing of the bladder <NUM> at the webbing 16D between adjacent chambers <NUM> and <NUM>, and adjacent chambers <NUM> and <NUM>.

<FIG> is a lateral side view of the bladder <NUM> of <FIG> showing the lateral arm portion 16B extending from the heel portion 16A to the terminal end <NUM>. <FIG> is a medial side view of the bladder <NUM>, showing the medial arm portion 16C extending from the heel portion 16A to the terminal end <NUM>, which is rearward of the terminal end <NUM>. <FIG> is a rear view of the bladder <NUM> showing the rear of the heel portion 16A. <FIG> is a front view of the bladder <NUM>. <FIG> is a cross-sectional view of the bladder <NUM> taken at lines <NUM>-<NUM> in <FIG>. The cross-section is taken through the unsealed channel <NUM>. <FIG> are cross-sectional views of the bladder <NUM> taken at lines <NUM>-<NUM>, <NUM>-<NUM>, and <NUM>-<NUM> in <FIG>, respectively. As with bladder <NUM>, The perimeter flange <NUM> is higher at the exterior side surface <NUM> of the bladder <NUM> than at inner side surfaces of the arm portions 16B, 16C, causing the first polymeric sheet <NUM> to slope downward and transversely inward as shown to better wrap around and support the periphery of the foot.

The peripheral chamber <NUM> and the heel chamber <NUM> of the bladders <NUM> and <NUM> are identical. For efficiencies in manufacturing, the bladder <NUM> has a groove G1 in the webbing on either the first polymeric sheet <NUM> or the second polymeric sheet <NUM> (shown here in the bottom sheet (second polymeric sheet <NUM>)) that serves as a guide at which the bladder <NUM> may be optionally trimmed (not according to the claimed invention) to remove the rear midfoot chamber <NUM>, the front midfoot chamber <NUM>, and the forefoot chamber <NUM> from the bladder <NUM>. The groove G1 may be formed in the bladder <NUM> during molding, such as during thermoforming. The groove G1 extends between the medial arm portion 16C and the front midfoot chamber <NUM>, between the medial arm portion 16C and the rear midfoot chamber <NUM>, between a rear of the rear midfoot chamber <NUM> and the heel chamber <NUM>, between rear midfoot chamber <NUM> and the lateral arm portion 16B, and between the front midfoot chamber <NUM> and the lateral arm portion 16B. If trimmed at the groove G1 (not according to the claimed invention), the bladder <NUM> is transformed into the bladder <NUM>, with the forward edge <NUM> and the flanges 16E of <FIG> defined by and remaining after the trimming. Trimming at the groove G1 may occur any time after forming of the bladder <NUM>. Inflation of the chambers <NUM>, <NUM> may occur after trimming. Trimming may extend across the channels <NUM> and <NUM> shown in <FIG>, and these may be sealed after inflation, resulting in plugging of the ports 50A, 50B of <FIG>.

<FIG> show top and bottom views, respectively, of another alternative embodiment of a bladder <NUM>. The bladder <NUM> is alike in many ways to bladders <NUM> and <NUM>. For example, the bladder <NUM> has a peripheral chamber <NUM> and a heel chamber <NUM> that are fluidly isolated from one another. The heel chamber <NUM> and the peripheral chamber <NUM> are the only fluid-filled chambers of the bladder <NUM>. While the bladders <NUM> and <NUM> are thermoformed from two polymeric sheets and the various chambers inflated to desired inflation pressures, the bladder <NUM> is blow molded. In some examples, the chambers <NUM> and <NUM> may be pressurized to different internal pressures, with the peripheral chamber <NUM> at a greater pressure than the heel chamber <NUM>. In other examples, the chambers <NUM>, <NUM> are not pressurized (e.g., they contain air or another gas at ambient pressure). In the bladder <NUM> shown herein, the chambers <NUM>, <NUM> are at ambient pressure and are isolated from one another.

For example, the bladder <NUM> may be blow molded from a parison of thermoplastic polyurethane material. In blow molding, a molten or otherwise softened elastomeric material, such as thermoplastic polyurethane pellets molten into the shape of a tube (i.e., a parison) is disposed in a mold having the desired overall shape and configuration of the bladder <NUM>. The mold may have multiple components, such as first and second mold halves that come together to form a mold cavity, with an opening at one location through which air is blown to mold the material to the walls of the mold. The air induces the liquefied elastomeric material to conform to the shape of the inner surfaces of the mold, thereby forming the chambers <NUM>, <NUM>, which are then sealed.

Because varying the inflation pressure is not available to affect support and cushioning in an embodiment in which the chambers <NUM>, <NUM> are unpressurized, the shape, volume, and geometry of the chambers <NUM>, <NUM> are tuned in order to provide desired support and cushioning. In an unpressurized embodiment, a configuration of the geometry and volume of the heel chamber <NUM> may lead to resilient deformation during dynamic loading, providing a rebound toward its height and shape prior to the dynamic load. This creates a cushioning effect that is greater than a deformation of a chamber that deforms by simply flattening under a dynamic load with little or no rebound, as can occur in an unpressurized chamber not tuned in geometry and volume for resilient deformation with rebound under a dynamic load. Adjacent components of the sole structure in which a bladder is incorporated also influence the ability of the bladder to resiliently deform with a cushioning rebound. For example, an overlying foam midsole layer and an underlying outsole influence the compression and rebound characteristics of the bladder during dynamic load events.

Accordingly, the unpressurized peripheral chamber <NUM> and the heel chamber <NUM> are shaped slightly differently from the corresponding pressurized chambers <NUM>, <NUM> of the thermoformed bladders <NUM> and <NUM>. In order to provide sufficient stability given that the bladder <NUM> is unpressurized, the bladder <NUM> is lower in profile than the bladders <NUM> and <NUM> in that the overall height of the peripheral chamber <NUM> is less than that of the peripheral chamber <NUM>, and the overall height of the heel chamber <NUM> is less than that of the heel chamber <NUM>. A lower profile also reduces the overall height of the sole structure that includes the bladder <NUM> when the heights of an outsole and any overlying midsole layers are added to the height of the bladder <NUM>. A reduction in overall height may be advantageous for stability in footwear configured for toddlers, preschoolers, and older children. Additionally, the shape of the peripheral chamber <NUM> is different than that of the peripheral chamber <NUM>. The peripheral chamber <NUM> has an inner wall 216D (i.e., the wall bordering the webbing 16D) that is steeper (i.e., closer to vertical) than the outer wall 216E at least directly outward of the heel chamber <NUM>. This helps to decrease the width of the peripheral chamber <NUM> relative to a chamber with a more gradual slope at the inner wall 216D. This provides greater stiffness to the peripheral chamber <NUM>, enabling greater peripheral support than would be provided if the peripheral chamber <NUM> had a more gradually upward and outward sloping surface more symmetrical to that of the outer wall 216E.

The peripheral chamber <NUM> has a heel portion 216A, a lateral arm portion 216B, and a medial arm portion 216C, arranged as described with respect to the corresponding portions 16A, 16B, and 16C of the peripheral chamber <NUM> in <FIG>. The forward edge <NUM> of the webbing 16D is trimmed with rounded corners <NUM> rather than the distinct corners shown in <FIG>.

A perimeter flange formed during molding of the bladder may extend along the outer perimeter of the peripheral chamber at perimeter flange location <NUM> and may be trimmed away. The perimeter flange location <NUM> may be relatively high along the outer wall of the peripheral chamber <NUM>, as shown on the like peripheral chamber <NUM> of the bladder <NUM> in <FIG>, or the perimeter flange location <NUM> may be relatively low, as described herein with respect to perimeter flange location <NUM> of the bladder <NUM> of <FIG>.

The peripheral chamber <NUM> is relatively more narrow than the peripheral chamber <NUM> and the heel chamber <NUM> is relatively wider and of greater volume than the heel chamber <NUM>. A ratio of the overall width W3 of any portion of the peripheral chamber <NUM> to a width W4 of the bladder <NUM> at a cross-section taken perpendicular to the longitudinal midline L of the bladder <NUM> is less than a ratio of the width W5 of a corresponding portion of the peripheral chamber <NUM> of the bladder <NUM> or <NUM> to a width W6 of the bladder <NUM> or <NUM>. By making the unpressurized peripheral chamber <NUM> relatively narrow, it will tend to collapse under loading less than would a wider unpressurized peripheral chamber, thereby providing greater peripheral support. Additionally, because the peripheral chamber <NUM> is relatively narrow, there is sufficient space between the arm portions 216B, 216C (assuming a given overall width W4) to make the heel chamber <NUM> wider and less elongated than the heel chamber <NUM>. This enables the heel chamber <NUM> to have a greater volume than if the peripheral chamber <NUM> were wider, while still having a lower profile than the peripheral chamber <NUM> so that loading of the heel chamber <NUM> is secondary to loading of the peripheral chamber <NUM>. The greater volume, wider heel chamber <NUM> is able to resiliently deform (e.g., rebound under dynamic loading) and provide cushioning despite it being unpressurized. Referring to <FIG>, there are separate sealed fill ports 250A, 250B for the peripheral chamber <NUM> and the heel chamber <NUM>, similar to fill ports 50A, 50B. The peripheral chamber <NUM> and the heel chamber <NUM> are fluidly isolated from one another. In a pressurized embodiment, the chambers <NUM>, <NUM> may have different fluid pressures. In one example, the peripheral chamber <NUM> is inflated to and retains fluid at a first fluid pressure, and the heel chamber <NUM> is inflated to and retains fluid at a second fluid pressure less than the first fluid pressure.

<FIG> show another alternative embodiment of a bladder <NUM>. The bladder <NUM> is alike in many ways to bladder <NUM> except that it includes the slightly different peripheral chamber <NUM> and heel chamber <NUM> as described with respect to bladder <NUM>, a single fill port <NUM>, similar to fill port <NUM>, and in addition to sealed channel <NUM> fluidly isolating the peripheral chamber <NUM> from all other chambers, each of the channels <NUM>, <NUM>, and <NUM> are sealed so that each of the forefoot chamber <NUM>, the front midfoot chamber <NUM>, and the rear midfoot chamber <NUM> are fluidly isolated from one another and from the heel chamber <NUM>. The peripheral chamber <NUM>, the heel chamber <NUM>, the rear midfoot chamber <NUM>, the front midfoot chamber <NUM>, and the forefoot chamber <NUM> are the only fluid-filled chambers of the bladder <NUM>. In a pressurized version, this configuration allows up to five different fluid pressures in the five fluidly-isolated chambers <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. Alternatively, channel <NUM> could be left unsealed so that chambers <NUM> and <NUM> are in fluid communication, or channel <NUM> could be left unsealed so that chambers <NUM> and <NUM> are in fluid communication, or channel <NUM> could be left unsealed so that chambers <NUM> and <NUM> are in fluid communication, or any combination of two of the three channels <NUM>, <NUM>, and <NUM> could be left unsealed. If one or more of the adjacent chambers <NUM>, <NUM>, and <NUM> are in fluid communication with one another, even in an unpressurized version, air would be pushed from a more rearward chamber to a more forward chamber with which it is in communication during a forward foot roll, increasing the pressure in the more forward chamber to provide support for toe off. In an unpressurized version, all of the chambers <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> would be at atmospheric pressure when in the static state.

<FIG> is a top view of an alternative embodiment of a bladder <NUM>. <FIG> is a bottom view of the bladder of <FIG>. The bladder <NUM> is alike in many ways to the bladder <NUM>, and includes a peripheral chamber <NUM> and a heel chamber <NUM>. The heel chamber <NUM> and the peripheral chamber <NUM> are the only fluid-filled chambers of the bladder <NUM>. The bladder <NUM> is blow molded, and the peripheral chamber <NUM> and the heel chamber <NUM> are unpressurized and isolated from one another. Stated differently, the chambers <NUM>, <NUM> are at ambient pressure and are isolated from one another.

The peripheral chamber <NUM> includes a medial arm portion 416C, a lateral arm portion 416B, and a heel portion 416A from which the medial arm portion 416C and lateral arm portion 416B extend, and these portions 416A, 416B, and 416C arranged as described with respect to the corresponding portions 16A, 16B, and 16C of the peripheral chamber <NUM> in <FIG>. Webbing 16D connects the peripheral chamber <NUM> to the heel chamber <NUM>.

The bladder <NUM> includes a single channel <NUM> through which air is blown during the blow molding process to form the chambers <NUM>, <NUM>. The channel <NUM> is sealed shut at weld <NUM> (by the mold portions of the blow mold or after removal from the mold) to isolate the chambers <NUM>, <NUM> from one another after the blown air forms the bladder <NUM> with the chambers <NUM>, <NUM>. Like bladder <NUM>, the unpressurized chambers <NUM>, <NUM> are tuned in order to provide desired support and cushioning. In order to provide sufficient stability given that the bladder <NUM> is unpressurized, the bladder <NUM> is lower in profile than the bladders <NUM> and <NUM> in that the overall height of the peripheral chamber <NUM> is less than that of the peripheral chamber <NUM>, and the overall height of the heel chamber <NUM> is less than that of the heel chamber <NUM>. Additionally, the shape of the peripheral chamber <NUM> is different than that of the peripheral chamber <NUM>. The peripheral chamber <NUM> has an inner wall 416D (i.e., the wall bordering the webbing 16D) that is steeper (i.e., closer to vertical) than the outer wall 416E, as best shown in <FIG>. This helps to decrease the width of the peripheral chamber <NUM> relative to a chamber with a more gradual slope at the inner wall 416D. This provides greater stiffness to the peripheral chamber <NUM>, enabling greater peripheral support, than would be provided if the inner wall 416D had a more gradually upward and outward sloping surface more symmetrical to that of the outer wall 416E.

The peripheral chamber <NUM> is relatively more narrow than the peripheral chamber <NUM> and the heel chamber <NUM> may be relatively wider and of greater volume than the heel chamber <NUM>. The peripheral chamber <NUM> is even relatively more narrow than peripheral chamber <NUM>, and the heel chamber <NUM> is narrower than heel chamber <NUM>. A ratio of the width W7 of any portion of the peripheral chamber <NUM> to the overall width W8 of the bladder <NUM> at a cross-section taken perpendicular to the longitudinal midline L of the bladder <NUM> is less than a ratio of the width W5 of a corresponding portion of the peripheral chamber <NUM> of the bladder <NUM> or <NUM> to an overall width W6 of the bladder <NUM> or <NUM> at a corresponding cross-section. By configuring the unpressurized peripheral chamber <NUM> to be relatively narrow, it will tend to collapse under loading less than would a wider unpressurized peripheral chamber, thereby providing greater peripheral support. Additionally, because the peripheral chamber <NUM> is relatively narrow, there is sufficient space between the arm portions 416B, 416C (assuming a given overall width W8) to make the heel chamber <NUM> wider and less elongated than the heel chamber <NUM>. This enables the heel chamber <NUM> to have a greater volume than if the peripheral chamber <NUM> were wider, while still having a lower profile than the peripheral chamber <NUM> so that loading of the heel chamber <NUM> is secondary to loading of the peripheral chamber <NUM>. The greater volume, wider heel chamber <NUM> is able to resiliently deform (e.g., rebound under dynamic loading) and provide cushioning despite it being unpressurized. Additionally, the relatively narrow peripheral chamber <NUM> provides for a wider webbing 16D surrounding the heel chamber <NUM>, giving the heel chamber <NUM> more space to deform outward during dynamic loading without interference from the peripheral chamber <NUM>. The forward edge <NUM> of the webbing 16D is trimmed with rounded corners <NUM> rather than the distinct corners shown in <FIG>.

Trimming of the bladder <NUM> at the forward edge <NUM> and at a perimeter flange 416F (shown in phantom in <FIG>) at perimeter flange location <NUM> (trimmed away in <FIG>) may occur with the bladder <NUM> in the blow molding machine. The molds may form multiple bladders <NUM> at once, with the molten polymeric material extending between adjacent bladders trimmed away by the blow molding machine when molding is complete. For example, interfacing mold portions may have edges that align at the perimeter flange location <NUM> to trim away the flange 416F. In the figures shown, the trimmed material is trimmed so closely at the perimeter flange location <NUM> that the flange 416F is not visible. The molds are configured so that the flange 416F and the perimeter flange location <NUM> along the exterior side surface <NUM> is closer to a lowest extremity <NUM> of the peripheral chamber <NUM> at the ground-facing surface <NUM> than to a highest extremity <NUM> of the peripheral chamber <NUM> at the foot-facing surface <NUM>. This positioning of the flange 416F and the perimeter flange location <NUM> is at least in the heel region <NUM> along the lateral periphery 20B, the rear periphery 20A, and the medial periphery 20C, and, as shown, preferably also in the forefoot region <NUM> and the midfoot region <NUM>. <FIG> best shows the relatively low position of the perimeter flange location <NUM> in comparison to the location of the flange <NUM> on the exterior side surface <NUM> of the bladder <NUM> in <FIG>. This lower position results in the bladder <NUM> being wider at the ground-facing surface <NUM> than at the foot-facing surface <NUM> than it would be if the flange 416F and perimeter flange location <NUM> were higher, like the flange <NUM> in <FIG>.

As can be seen in <FIG>, most of the exterior side surface <NUM> flares outward from top to bottom, whereas in <FIG>, most of the exterior side surface <NUM> flares inward. A bladder that is wider in the transverse direction toward the bottom than toward the top, as is the bladder <NUM> due to the placement of perimeter flange location <NUM>, provides greater stability than a narrower bladder of the same length. When assembled with other components of an article of footwear, an outsole, such as outsole <NUM> of <FIG> would extend to the perimeter flange location <NUM> and would end at the perimeter flange location <NUM> without wrapping further up the exterior side surface <NUM>. This configuration also maximizes the visible exterior side surface <NUM> while at the same time generally not exposing the perimeter flange location <NUM> because it would extend just along the outsole <NUM>. Stated differently, the outsole <NUM> would extend to the peripheral flange location <NUM>. In some embodiments, the outsole <NUM> may terminate at the peripheral flange location <NUM> so that an upper edge of the outsole is coincident with the peripheral flange location <NUM>. In other embodiments, the outsole <NUM> may extend upward beyond the peripheral flange location <NUM> to cover the peripheral flange location <NUM>.

Although any of the bladders shown and described herein may be scaled to foot sizes from infant to adult, the bladder <NUM> may be especially suitable for a toddler, as a toddler foot is, on average, wider and shorter than the foot of a preschooler and the foot of a grade schooler. A last on which a footwear upper is placed and a sole structure is secured will be wider and shorter when configured for a footwear size generally worn by toddlers than a last configured for a footwear size generally worn by preschoolers, and the last configured for the footwear size generally worn by preschoolers will be shorter and possibly wider than a last configured for a footwear size generally worn by grade schoolers. The wider bladder <NUM> with the perimeter flange location <NUM> and the relatively wide width toward the bottom at the perimeter flange location <NUM> is thus especially suitable for a toddler.

<FIG> show that the lateral arm portion 416B and the medial arm portion 416C of the peripheral chamber <NUM> taper in height from the heel portion 416A to the respective terminal ends <NUM>, <NUM>, and that the peripheral chamber <NUM> is greatest in height at the heel portion 416A. <FIG> is a rear view of the bladder <NUM>. <FIG> is a front view of the bladder <NUM> and shows both the arm portions 416B, 416C, and heel portion 416A of the peripheral chamber <NUM> and also shows the heel chamber <NUM>. <FIG> is a cross-sectional view of the bladder <NUM> taken at lines <NUM>-<NUM> in <FIG>. It is evident from <FIG> that the elevation of the heel chamber <NUM> is less than the elevation of the heel portion 416A of the peripheral chamber <NUM>. Due to this height differential, as well as the tapering height of the peripheral chamber <NUM> from the heel portion 416A to the terminal ends <NUM>, <NUM>, during wear, an article of footwear that includes the bladder <NUM> (such as article of footwear <NUM> if the bladder <NUM> were used instead of bladder <NUM>) will typically first make contact with the ground at the heel region <NUM>, and the much taller peripheral chamber <NUM> will be loaded before the heel chamber <NUM>. In an embodiment in which the heel chamber <NUM> is unpressurized, due to its volume, height, and width, as well as the spacing from the arm portions 416B, 416C, it may resiliently deform under dynamic loading, providing cushioning under the calcaneus bone.

<FIG> is a top view of another alternative embodiment of a bladder <NUM> within the scope of the disclosure. <FIG> is a bottom view of the bladder <NUM> of <FIG>. The bladder <NUM> has many of the same features and components of the bladder <NUM> of <FIG>, and like reference numbers are used to identify those features and components. The bladder <NUM> is thermoformed from a first polymeric sheet <NUM> and a second polymeric sheet <NUM> as described with respect to bladder <NUM>. The bladder does not include the forefoot chamber <NUM>, but does include the rear midfoot chamber <NUM> and the front midfoot chamber <NUM>. The heel chamber <NUM>, the peripheral chamber <NUM>, the rear midfoot chamber <NUM>, and the front midfoot chamber <NUM> are the only fluid-filled chambers of the bladder <NUM>.

For efficiencies in manufacturing, the bladder <NUM> has a groove G2 in the webbing 16D on either the first polymeric sheet <NUM> or the second polymeric sheet <NUM> (shown here in the top sheet (first polymeric sheet <NUM>)) that will serve as a guide at which the bladder <NUM> may be optionally trimmed (not according to the claimed invention). The groove G2 may be formed in the bladder <NUM> during molding, such as during thermoforming. The groove G2 extends between the medial arm portion 16C and the front midfoot chamber <NUM>, between the medial arm portion 16C and the rear midfoot chamber <NUM>, between a rear of the rear midfoot chamber and the heel chamber <NUM>, between the rear midfoot chamber <NUM> and the lateral arm portion 16B, and between the front midfoot chamber <NUM> and the lateral arm portion 16B. The bladder <NUM> may be trimmed at the portions of the webbing 16D extending along the inner side of the arm portion 16B and at the forward edge <NUM>, so that only a flange 16E remains at these portions. If trimmed at the groove G2 (not according to the claimed invention), the rear midfoot chamber <NUM> and the front midfoot chamber <NUM> are removed from the bladder <NUM>, and the bladder <NUM> is transformed into a bladder like the bladder <NUM>, with the forward edge <NUM> and the flanges 16E of <FIG> defined by and remaining after the trimming, except with more rounded corners at corners <NUM>. Trimming may occur any time after forming of the bladder <NUM>. Inflation of the chambers <NUM>, <NUM> may occur after trimming. The bladder <NUM> may be trimmed across the port <NUM>, which may be sealed by weld <NUM> after inflation. If trimmed at the groove G2 (not according to the claimed invention), the trimming extends across the channel <NUM>, which may be sealed by weld <NUM> after inflation of the heel chamber <NUM>.

The bladder <NUM> includes only a single fill port <NUM> extending from the front side <NUM> of the front midfoot chamber <NUM>. The fill port <NUM> is sealed in <FIG> as shown by weld <NUM>. The various chambers of the bladder <NUM> may be filled to different pressures using only the single fill port <NUM> due to channels that fluidly connect adjacent chambers, and any or all of the channels may be sealed following inflation to isolate the chambers connected by the channel(s). More specifically, referring to <FIG>, the bladder <NUM> includes a channel <NUM> extending between and fluidly connecting the front midfoot chamber <NUM> and the rear midfoot chamber <NUM>, and a channel <NUM> extending between and fluidly connecting the rear midfoot chamber <NUM> and the heel chamber <NUM>. Channel <NUM> is the only channel extending between the front midfoot chamber <NUM> and the rear midfoot chamber <NUM>. Channel <NUM> is the only channel extending between the rear midfoot chamber <NUM> and the heel chamber <NUM>. Additionally, a channel <NUM> extends between the front midfoot chamber <NUM> and the peripheral chamber <NUM>. Channel <NUM> is the only channel extending from the peripheral chamber <NUM>. In one example, the channels <NUM>, <NUM>, and <NUM> may be formed by disposing anti-weld material between the polymeric sheets <NUM>, <NUM> to prevent sealing of the sheets <NUM>, <NUM> to one another at the channels. One or more of the channels, such as channel <NUM>, may be subsequently sealed by a heat weld <NUM>. The channel <NUM> fluidly connects the front midfoot chamber <NUM> and the peripheral chamber <NUM> prior to sealing the channel <NUM> at the weld <NUM>, and the front midfoot chamber <NUM> and the peripheral chamber <NUM> are fluidly isolated from one another once the channel <NUM> is sealed. In the embodiment shown, the channel <NUM> is not sealed so that the front midfoot chamber <NUM> and the rear midfoot chamber <NUM> are in fluid communication with one another via the channel <NUM>. In the embodiment shown, channel <NUM> is sealed by a heat weld <NUM>. The channel <NUM> fluidly connects the rear midfoot chamber <NUM> and the heel chamber <NUM> prior to sealing the channel <NUM> at the weld <NUM>. The rear midfoot chamber <NUM> and the heel chamber <NUM> are fluidly isolated from one another once the channel <NUM> is sealed. The heel chamber <NUM> and each of the front midfoot chamber <NUM> and the rear midfoot chamber <NUM> are fluidly isolated from the peripheral chamber <NUM>.

The peripheral chamber <NUM> may be inflated to a first fluid pressure that is the relatively highest pressure of the chambers by, for example, initially filling it to a predetermined, relatively high pressure, sealing the channel <NUM> via the weld <NUM>, filling or releasing fluid from the fill port <NUM> until a predetermined pressure is achieved in the heel chamber <NUM>, sealing the channel <NUM> via the weld <NUM>, and filling or releasing fluid from the fill port <NUM> until a predetermined pressure is achieved in the fluidly connected rear midfoot chamber <NUM> and front midfoot chamber <NUM>, and then sealing the port <NUM> via a weld <NUM>. In the embodiment shown, the channel <NUM> is not sealed, so that the chambers <NUM> and <NUM> are at the same fluid pressure, at least when in a static state.

In one non-limiting example, the first fluid pressure in the peripheral chamber <NUM> may be more than <NUM> pounds per square inch above ambient pressure, up to <NUM> pounds per square inch above ambient pressure. The second fluid pressure in the heel chamber <NUM>, may be ambient pressure or a pressure up to <NUM> pounds per square inch more than ambient pressure, and the fluid pressure in the chambers <NUM>, <NUM> may be the same or different than that in the heel chamber <NUM> and may be ambient pressure or a pressure up to <NUM> pounds per square inch more than ambient pressure. In a specific example, the peripheral chamber <NUM> may be inflated to and sealed to retain fluid at <NUM> pounds per square inch above ambient pressure, and the chambers <NUM>, <NUM>, and <NUM> may be inflated to and sealed to retain fluid at <NUM> pounds per square inch above ambient pressure. The fluid communication between the chambers <NUM> and <NUM> allows the fluid to be displaced from one chamber to the next during dynamic loading. For example, during a forward stride, fluid may be displaced from the rear midfoot chamber <NUM> to the front midfoot chamber <NUM>, increasing the pressure in the chamber <NUM> during dynamic loading and providing increased compressive stiffness. Sealing the heel chamber <NUM> from the other chambers may further enable it to provide resilient deformation during dynamic loading even at the relatively low inflation pressure of <NUM> pounds per square inch above ambient pressure. In other alternatives, the channel <NUM> could be sealed instead of the channel <NUM>, or both of the channels <NUM> and <NUM> could be sealed, or neither of the channels <NUM> and <NUM> may be sealed. The port <NUM> and channels <NUM>, <NUM>, and <NUM> are disposed at the bottom side (e.g., at the ground-facing surface <NUM>) of the bladder <NUM>, and are formed mainly by the second polymeric sheet <NUM>, so that they do not affect the contours of the foot-facing surface <NUM>, are therefore not felt by the wearer, and do not interfere with flexing of the bladder <NUM> at the webbing 16D between adjacent chambers <NUM> and <NUM>.

In still another embodiment, instead of thermoforming the bladder <NUM> without a forefoot chamber <NUM> as shown, the bladder <NUM> could instead initially be thermoformed with a forefoot chamber <NUM> and then trimmed along the webbing 16D between forefoot chamber <NUM> and front midfoot chamber <NUM> before sealing port <NUM>. A groove could be provided around the forefoot chamber <NUM> to facilitate such trimming, such as described with respect to groove G2 except the groove would only extend around the forefoot chamber <NUM>.

<FIG> is a lateral side view of an article of footwear <NUM> including an upper <NUM> and a sole structure <NUM>. The sole structure <NUM> includes a cushioning element which, in the embodiment shown is the bladder <NUM> of <FIG>, the outsole <NUM>, and a midsole layer <NUM> as described herein. Although shown as the bladder <NUM>, the cushioning element could instead be a foam material or another resiliently deformable material that provides cushioning, instead of a bladder with a fluid-filled peripheral chamber. <FIG> is a medial side view of the article of footwear <NUM> of <FIG>. The article of footwear <NUM> includes an upper <NUM> that is a slip-on upper, shown without laces, and with a heel pull <NUM> secured at the heel region <NUM> for ease in pulling the article of footwear <NUM> onto a foot. Other alternative upper configurations could instead be used with the sole structure <NUM>. The upper <NUM> is secured to and overlays the midsole layer <NUM>. The midsole layer <NUM> is between the upper <NUM> and the bladder <NUM>.

As previously discussed with respect to the bladder <NUM>, the lateral arm portion 416B extends further into the forefoot region <NUM> than the medial arm portion 416C, as the terminal end <NUM> is further forward than the terminal end <NUM>. The exterior side surface <NUM> of the bladder <NUM> is visible at the lateral side <NUM> along the lateral arm portion 416B from the terminal end <NUM> to the heel portion 16A. The exterior side surface <NUM> of the bladder <NUM> is also visible at the medial side <NUM> along the medial arm portion 416C from the terminal end <NUM> to the heel portion 416A. In some examples, as shown with respect to bladder <NUM>, the entire exterior surface <NUM> of the bladder <NUM> may be exposed between the midsole layer <NUM> and the outsole <NUM> at the medial arm portion 416C, the lateral arm portion 416B, and the heel portion 416A.

The midsole layer <NUM> may be, for example, a foam material and can have a different compressive stiffness than the compressive stiffnesses of the peripheral chamber <NUM> and a different compressive stiffness than the heel chamber <NUM> (not visible in the side views of <FIG>, but shown in <FIG>, for example). The midsole layer <NUM> is a full length midsole layer, and is disposed in the forefoot region <NUM>, the midfoot region <NUM> and the heel region <NUM>. The midsole layer <NUM> extends from the front of the forefoot region <NUM> to the rear of the heel region <NUM>. The midsole layer <NUM> extends over the outsole <NUM> in the forefoot region <NUM>, over the top surface and the surface of the inner wall 416D of the lateral and medial arm portions 416B, 416C, and the top surface and surface of the inner wall of the heel portion 416A, over the webbing 16D and over the heel chamber <NUM>, without covering the exterior side surface <NUM> of the bladder <NUM>. Stated differently, the midsole layer <NUM> leaves the exterior side surface <NUM> exposed so that the exterior side surface <NUM> of the bladder <NUM> is visible at the lateral side <NUM> of the footwear <NUM>, as shown in <FIG>, at the medial side <NUM> as shown in <FIG>, and at the rear of the heel region <NUM> as is evident in both views. This visibility is possible because the midsole layer <NUM> and the outsole <NUM> are arranged so that the exterior side surface <NUM> of the bladder <NUM> is exposed between the midsole layer <NUM> and the outsole <NUM> at the medial arm portion 416C, the lateral arm portion 416B, and the heel portion 416A. The outsole <NUM> is shown extending to the perimeter flange location <NUM>. For example, the upper edge of the outsole <NUM> is shown terminating at the perimeter flange location <NUM> so that the outsole <NUM> is coincident with the perimeter flange location <NUM>. In such an embodiment, the perimeter flange disposed at the perimeter flange location <NUM> is not readily apparent on the exterior side surface <NUM>. In other embodiments, the outsole <NUM> may extend upward over the perimeter flange location <NUM> to cover the perimeter flange and the perimeter flange location <NUM>.

The midsole layer <NUM> fills the recessed space shown in <FIG> between the heel chamber <NUM> and the peripheral chamber <NUM> on the webbing 16D and overlays the heel chamber <NUM>. By filling the recessed space, the midsole layer <NUM> provides some support at the inner wall 416D to help limit an inward collapse of the peripheral chamber <NUM> under dynamic loading.

For bladders disclosed herein that are molded by thermoforming, such as bladders <NUM>, <NUM>, and <NUM>, a method of manufacturing footwear may include any or all of the steps of the method <NUM> set forth in Table <NUM> below, as discussed herein.

For bladders disclosed herein that are molded by blow molding, such as bladders <NUM>, <NUM>, and <NUM>, a method of manufacturing footwear may include any or of the steps of the method <NUM> set forth in Table <NUM> below, as discussed herein.

Accordingly, the bladders <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> disclosed herein have a unique combination of fluid-filled chambers that are shaped and configured to provide distinct cushioning profiles and support to different portions of a wearer's foot. In any of the embodiments described herein, a cushioning element could be used in place of the bladder <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, may have the same shape and features of the bladders <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, as described, and the cushioning element could instead be a foam material or another resiliently deformable material instead of a bladder with a fluid-filled chamber such as the fluid-filled peripheral chambers and the fluid-filled heel chambers described herein.

As used in the description and the accompanying claims, a value is considered to be "approximately" equal to a stated value if it is neither more than <NUM> percent greater than nor more than <NUM> percent less than the stated value.

The term "any of' is understood to include any possible combination of referenced items, including "any one of" the referenced items.

The term "longitudinal" refers to a direction extending a length of a component. For example, a longitudinal direction of a shoe extends between a forefoot region and a heel region of the shoe. The term "forward" or "anterior" is used to refer to the general direction from a heel region toward a forefoot region, and the term "rearward" or "posterior" is used to refer to the opposite direction, i.e., the direction from the forefoot region toward the heel region. In some cases, a component may be identified with a longitudinal axis as well as a forward and rearward longitudinal direction along that axis. The longitudinal direction or axis may also be referred to as an anterior-posterior direction or axis.

The term "transverse" refers to a direction extending a width of a component. For example, a transverse direction of a shoe extends between a lateral side and a medial side of the shoe. The transverse direction or axis may also be referred to as a lateral direction or axis or a mediolateral direction or axis.

The term "vertical" refers to a direction generally perpendicular to both the lateral and longitudinal directions. For example, in cases where a sole is planted flat on a ground surface, the vertical direction may extend from the ground surface upward. It will be understood that each of these directional adjectives may be applied to individual components of a sole. The term "upward" or "upwards" refers to the vertical direction pointing towards a top of the component, which may include an instep, a fastening region and/or a throat of an upper. The term "downward" or "downwards" refers to the vertical direction pointing opposite the upwards direction, toward the bottom of a component and may generally point towards the bottom of a sole structure of an article of footwear.

Claim 1:
A sole structure (<NUM>, <NUM>) for an article of footwear (<NUM>, <NUM>), the sole structure (<NUM>, <NUM>) comprising:
a bladder (<NUM>, <NUM>) defining a fluid-filled peripheral chamber (<NUM>) and a fluid-filled heel chamber (<NUM>);
wherein the peripheral chamber (<NUM>) is configured as an elongated tube, the peripheral chamber (<NUM>) having a heel portion (16A) establishing a rear periphery (20A) of the bladder (<NUM>, <NUM>), a lateral arm portion (16B) extending from the heel portion (16A) and establishing a lateral periphery (20B) of the bladder (<NUM>, <NUM>), and a medial arm portion (16C) extending from the heel portion (16A) and establishing a medial periphery (20C) of the bladder (<NUM>, <NUM>);
wherein the bladder (<NUM>, <NUM>) includes webbing (16D) connecting the heel chamber (<NUM>) to the peripheral chamber (<NUM>), with the heel chamber (<NUM>) disposed between the medial arm portion (16C) and the lateral arm portion (16B) and forward of the peripheral chamber (<NUM>) in a heel region (<NUM>) of the bladder (<NUM>, <NUM>);
wherein the peripheral chamber (<NUM>) and the heel chamber (<NUM>) are sealed and are fluidly isolated from one another;
wherein the bladder (<NUM>, <NUM>) defines at least two additional fluid-filled chambers fluidly isolated from the peripheral chamber (<NUM>), the at least two additional fluid-filled chambers including a rear midfoot chamber (<NUM>) and a front midfoot chamber (<NUM>), the rear midfoot chamber (<NUM>) disposed between and connected to the heel chamber (<NUM>) and the front midfoot chamber (<NUM>) by the webbing (16D), and the rear midfoot chamber (<NUM>) and the front midfoot chamber (<NUM>) connected to the lateral arm portion (16B) and the medial arm portion (16C) by the webbing (16D); and
wherein the bladder (<NUM>, <NUM>) includes a groove (G1, G2) in the webbing (16D), the groove (G1, G2) extending between the medial arm portion (16C) and the front midfoot chamber (<NUM>), between the medial arm portion (16C) and the rear midfoot chamber (<NUM>), between a rear of the rear midfoot chamber (<NUM>) and the heel chamber (<NUM>), between the rear midfoot chamber (<NUM>) and the lateral arm portion (16B), and between the front midfoot chamber (<NUM>) and the lateral arm portion (16B).