Patent Description:
Sole structures generally include a layered arrangement extending between a ground surface and the upper. One layer of the sole structure includes an outsole that provides abrasion-resistance and traction with the ground surface. The outsole may be formed from rubber or other materials that impart durability and wear-resistance, as well as enhancing traction with the ground surface. Another layer of the sole structure includes a midsole disposed between the outsole and the upper. The midsole provides cushioning for the foot and may include a pressurized fluid-filled chamber that compresses resiliently under an applied load to cushion the foot by attenuating ground-reaction forces.

Fluid-filled chambers are generally formed from two polymer sheets of material that join together to define a peripheral bond of the fluid-filled chambers. A tool having upper and lower mold portions is generally used to impart a desired shape of the chamber and apply heat for joining the two polymer sheets together at the peripheral bond. A pressurized fluid is then supplied between the two polymer sheets to inflate the chamber.

While known systems and methods for manufacturing fluid-filled chambers have proven acceptable for their intended purposes, a continuous need for improvement in the relevant art remains. For example, a need exists for a system and method for manufacturing a fluid-filled chamber in a faster and less expensive manner by utilizing fewer toolsets, less expensive equipment, fewer processing steps, and a fewer operators.

Document <CIT> describes a process for making a cushioning component from a pair of sheets of flexible thermoplastic resin in which the sheets are placed against a pair of molds having hemispherical protrusions for forming opposing hemispherical indentations in the sheets. The indentations of the first sheet abut the indentations of the second sheet when the sheets are joined to complete the cushioning component. During the process, inserts may be positioned on the protrusions before the sheets are placed in the molds, and the inserts then may be adhered to the indentations during molding.

Document <CIT> describes a method of manufacturing an article of footwear. The method includes thermoforming the bladder element and the first outsole component and securing the second outsole component to the first outsole component.

Particular embodiments of the claimed invention are defined by the dependent claims.

The drawings described herein are for illustrative purposes only of selected configurations and not all possible implementations, and are not intended to limit the scope of the present disclosure.

Other aspects, features, and advantages will be apparent from the description, the drawings, and the claims.

Referring to <FIG> and <FIG>, an article of footwear <NUM> is provided and includes an upper <NUM> and a sole structure <NUM> attached to the upper <NUM>. The article of footwear <NUM> may be divided into one or more portions. The portions may include a forefoot portion <NUM>, a midfoot portion <NUM>, and a heel portion <NUM>. The forefoot portion <NUM> may correspond with toes and joints connecting metatarsal bones with phalanx bones of a foot. The midfoot portion <NUM> may correspond with an arch area of the foot, and the heel portion <NUM> may correspond with rear portions of the foot, including a calcaneus bone. The footwear <NUM> may include lateral and medial sides <NUM>, <NUM>, respectively, corresponding with opposite sides of the footwear <NUM> and extending through the portions <NUM>, <NUM>, <NUM>.

The upper <NUM> includes interior surfaces that define an interior void <NUM> that receives and secures a foot for support on the sole structure <NUM>. An ankle opening <NUM> in the heel portion <NUM> may provide access to the interior void <NUM>. For example, the ankle opening <NUM> may receive a foot to secure the foot within the void <NUM> and facilitate entry and removal of the foot to and from the interior void <NUM>. In some examples, one or more fasteners <NUM> extend along the upper <NUM> to adjust a fit of the interior void <NUM> around the foot while concurrently accommodating entry and removal of the foot therefrom. The upper <NUM> may include apertures such as eyelets and/or other engagement features such as fabric or mesh loops that receive the fasteners <NUM>. The fasteners <NUM> may include laces, straps, cords, hook-and-loop, or any other suitable type of fastener.

The upper <NUM> may include a tongue portion <NUM> that extends between the interior void <NUM> and the fasteners <NUM>. The upper <NUM> may be formed from one or more materials that are stitched or adhesively bonded together to form the interior void <NUM>. Suitable materials of the upper may include, but are not limited, textiles, foam, leather, and synthetic leather. The materials may be selected and located to impart properties of durability, air-permeability, wear-resistance, flexibility, and comfort.

In some implementations, the sole structure <NUM> includes an outsole <NUM> and a midsole <NUM> arranged in a layered configuration. The sole structure <NUM> (e.g., the outsole <NUM> and the midsole <NUM>) defines a longitudinal axis L. For example, the outsole <NUM> engages with a ground surface during use of the article of footwear <NUM> and the midsole <NUM> is disposed between the upper <NUM> and the outsole <NUM>. In some examples, the sole structure <NUM> may also incorporate additional layers such as an insole or sockliner (neither shown), which may reside within the interior void <NUM> of the upper <NUM> to receive a plantar surface of the foot to enhance the comfort of the footwear <NUM>. In some examples, a sidewall <NUM> surrounds a perimeter of the outsole <NUM> and separates the outsole <NUM> and the midsole <NUM> to define a cavity <NUM> therebetween.

In some configurations, the cavity <NUM> receives a fluid-filled chamber <NUM> filled with a pressurized fluid such as air, nitrogen, helium, sulfur, hexafluoride, or liquids/gels to enhance cushioning characteristics of the footwear <NUM> in response to ground-reaction forces. The fluid-filled chamber <NUM> defines an interior cavity that receives the pressurized fluid while providing a durable sealed barrier for retaining the pressurized fluid therein. According to an example that does not form part of the claimed invention, the chamber <NUM> may be formed from a first polymer sheet <NUM> that opposes the outsole <NUM> and a second polymer sheet <NUM> disposed on an opposite side of the chamber <NUM> than the first polymer sheet <NUM> and opposing the midsole <NUM>. In an example, the first and second polymer sheets <NUM>, <NUM> may be formed from a thermoplastic polyurethane (TPU) polymer. According to the claimed method, the fluid-filled chamber <NUM> is defined by coupling a first portion of a first sheet of material <NUM> to a second portion of the first sheet of material <NUM>.

According to an example that does not form part of the claimed invention, the first polymer sheet <NUM> may join to the second polymer sheet <NUM> to define a peripheral bond <NUM> (<FIG>) of the chamber <NUM>. Here, the peripheral bond <NUM> defines a predetermined area associated with the interior cavity that receives and retains the pressurized fluid therein. Accordingly, the peripheral bond <NUM> forms a sidewall <NUM> that extends around the periphery of the chamber <NUM> to connect the first polymer sheet <NUM> to the second polymer sheet <NUM>.

In some configurations, that do not form part of the claimed invention, the interior cavity of the fluid-filled chamber <NUM> also receives a tensile element <NUM> having a lower tensile layer <NUM> that attaches to first polymer sheet <NUM>, an upper tensile layer <NUM> that attaches to the second polymer sheet <NUM>, and a plurality of tensile elements <NUM> that extend between and connect the lower and upper tensile layers <NUM> and <NUM>, respectively, of the tensile element <NUM>. Thermobonding or another suitable fastening process (e.g., ultrasonic or radio frequency (RF) welding) may be used to secure the tensile element <NUM> to the chamber <NUM>. The tensile element <NUM> is operative to prevent the chamber <NUM> from expanding outward or otherwise distending due to the pressure of the fluid within the internal cavity of the chamber <NUM>. Namely, the tensile element <NUM> may limit expansion of the chamber <NUM> when under pressure to retain an intended shape of surfaces of the polymer sheets <NUM> and <NUM>.

The chamber <NUM> may define a length that extends substantially parallel to the longitudinal axis L of the sole structure <NUM> and may be formed to provide contours that conform to a profile of the bottom surface of the foot as well as an inner surface <NUM> of the outsole <NUM>. In some configurations, the chamber <NUM> defines a length that only extends through a portion of the length of the sole structure <NUM>. For instance, the chamber <NUM> may reside in the heel portion <NUM> of the sole structure <NUM> to provide cushioning for the heel of the foot. Additionally or alternatively, two or more chambers <NUM> may reside in the sole structure <NUM> each defining a length that extends along a portion of the length of the sole structure <NUM>. In other configurations, two or more chambers <NUM> may be layered upon one another that react differently in response to ground-reaction forces to provide gradient cushioning for the foot. While the sole structure <NUM> may include more than one chamber <NUM>, the sole structure <NUM> will be described and shown as including a single chamber <NUM> that extends along the longitudinal axis L from the forefoot portion <NUM> to the heel portion <NUM>.

The outsole <NUM> may include a ground-engaging surface <NUM> and the opposite inner surface <NUM>. The outsole <NUM> may attach to the upper <NUM>. In some examples, the sidewall <NUM> extends from the perimeter of the outsole <NUM> and attaches to the midsole <NUM> or the upper <NUM>. The example of <FIG> shows the outsole <NUM> attaching to the upper <NUM> proximate to a tip of the forefoot portion <NUM>. The outsole <NUM> generally provides abrasion-resistance and traction with the ground surface during use of the article of footwear <NUM>. The outsole <NUM> may be formed from one or more materials that impart durability and wear-resistance, as well as enhance traction with the ground surface. For example, rubber may form at least a portion of the outsole <NUM>.

The midsole <NUM> may include a bottom surface <NUM> and a footbed <NUM> disposed on an opposite side of the midsole <NUM> than the bottom surface <NUM>. Stitching <NUM> or adhesives may secure the midsole <NUM> to the upper <NUM>. The footbed <NUM> may be contoured to conform to a profile of the bottom surface (e.g., plantar) of the foot. The bottom surface <NUM> may oppose the inner surface <NUM> of the outsole <NUM> to define the cavity <NUM> therebetween. The midsole <NUM> may be formed from a flexible material that allows the midsole <NUM> to conform to the fluid-filled chamber <NUM> residing in the cavity <NUM> underneath the midsole <NUM>. In so doing, the flexible midsole <NUM> may correspond to a flexible stroble that allows the pressurized fluid retained by the fluid-filled chamber <NUM> within in the cavity <NUM> to interact with the profile of the bottom surface of a foot during gradient loading of the sole structure <NUM>. In some examples, the sidewall <NUM> may define a perimeter of the cavity <NUM> as well as a depth of the cavity <NUM> based on a length of separation between the bottom surface <NUM> and the inner surface <NUM>. One or more polymer foam materials may form the sidewall <NUM> to provide resilient compressibility under applied loads to attenuate ground-reaction forces.

<FIG> provides an exploded view of the article of footwear <NUM> showing the fluid-filled chamber <NUM> retaining the pressurized fluid (e.g., air), the inner surface <NUM> of the outsole <NUM>, and the bottom surface <NUM> of the midsole <NUM>. The length of the chamber <NUM> may extend between a first end <NUM> and a second end <NUM>. The first end <NUM> may be disposed proximate to the heel portion <NUM> of the sole structure <NUM> and the second end <NUM> may be disposed proximate to the forefoot portion <NUM> of the sole structure <NUM>. The chamber <NUM> may also include a thickness extending substantially perpendicular to the longitudinal axis L of the sole structure <NUM> and a width extending between the lateral side <NUM> and the medial side <NUM>. Accordingly, the length, the width, and the thickness of the chamber <NUM> may substantially occupy the cavity <NUM> defined by the inner surface <NUM> and the bottom surface <NUM> and may extend through the forefoot, midfoot, and heel portions <NUM>, <NUM>, <NUM>, respectively, of the outsole <NUM>.

Referring to <FIG>, a system <NUM> for use in manufacturing the fluid-filled chamber <NUM> (<FIG>) is shown. It will be appreciated that, while the system <NUM> is generally described herein as forming the fluid-filled chamber <NUM> of the article of footwear <NUM>, the system <NUM> may also be utilized to form a fluid-filled chamber for use in other implementations and configurations within the scope of the present disclosure.

The system <NUM> may include a housing <NUM>, a first fluid supply system <NUM>, a second fluid supply system <NUM>, and a press <NUM>. The housing <NUM> may include a primary or upper portion <NUM> and a secondary or lower portion <NUM>. As will be described in more detail below, during operation, the upper portion <NUM> may mate with the lower portion <NUM> such that the housing <NUM> defines an inner chamber <NUM>. In some implementations, the upper portion <NUM> may sealingly engage the lower portion <NUM> such that the chamber <NUM> is air-tight or otherwise operable to maintain a pressurized volume of fluid (e.g., air or other gas) within the chamber <NUM>. In this regard, the system <NUM> (e.g., the housing <NUM>) may include a pressure gauge <NUM> to measure and/or display the pressure of the volume of fluid within the chamber <NUM>. Accordingly, the chamber <NUM> may be referred to herein as the "pressure chamber <NUM>.

The first fluid supply system <NUM> may be in fluid communication with the housing <NUM>. In particular, the first fluid supply system <NUM> may be in fluid communication with the chamber <NUM>. For example, the first fluid supply system <NUM> may include a first fluid source <NUM> and a first fluid conduit <NUM>. The first fluid conduit <NUM> may allow fluid communication between the first fluid source <NUM> and the chamber <NUM>. Accordingly, during operation of the system <NUM>, the first fluid conduit <NUM> may deliver a first fluid from the first fluid source <NUM> to the chamber <NUM>, or from the chamber <NUM> to the first fluid source <NUM>. In some implementations, the first fluid may include nitrogen or another suitable gas or mixture of gases.

The first fluid source <NUM> may include a tank, a pump, a bellows, or any other suitable arrangement for delivering the first fluid to the chamber <NUM>. For example, as will be described in more detail below, in some implementations the first fluid source <NUM> includes a bellows that delivers the first fluid to the chamber <NUM> in a first mode of operation, and removes the first fluid from the chamber <NUM> in a second mode of operation.

The second fluid supply system <NUM> may be in fluid communication with the housing <NUM>. In particular, the second fluid supply system <NUM> may be in fluid communication with the chamber <NUM>. For example, the second fluid supply system <NUM> may include a second fluid source <NUM> and a second fluid conduit <NUM>. The second fluid conduit <NUM> may allow fluid communication between the second fluid source <NUM> and the chamber <NUM>. Accordingly, during operation of the system <NUM>, the second fluid conduit <NUM> may deliver a second fluid from the second fluid source <NUM> to the chamber <NUM>, or from the chamber <NUM> to the second fluid source <NUM>. In some implementations, the first fluid may include atmospheric air or another suitable gas or mixture of gases.

The second fluid source <NUM> may include a tank, a pump, a bellows, or any other suitable arrangement for delivering the second fluid to the chamber <NUM>. For example, as will be described in more detail below, in some implementations the second fluid source <NUM> includes a bellows that delivers the first fluid to the chamber <NUM> in a first mode of operation, and removes the first fluid from the chamber <NUM> in a second mode of operation.

The press <NUM> may include a top section <NUM> and a base section <NUM>. The top section <NUM> may include an upper platen <NUM> having a substantially flat (e.g., planar) first surface <NUM>, and the base section <NUM> may include a lower platen <NUM> having a substantially flat (e.g., planar) second surface <NUM>. The upper platen <NUM> may be reciprocally movable relative to the lower platen <NUM> to operate the press <NUM> between an open position (e.g., <FIG>), when the upper platen <NUM> is furthest away from the lower platen <NUM>, and a closed position (e.g., <FIG>), when the upper platen <NUM> is vertically aligned with, and proximate to, the lower platen <NUM> such that the first surface <NUM> and the second surface <NUM> are opposing, and in some instances, contacting, one another.

One or both of the upper and lower platens <NUM> and <NUM> may move (e.g., translate and/or pivot) relative to one another between the open and closed positions in a fully automated manner through the use of one or more actuating mechanisms (none shown). For example, in a not claimed example, the lower platen <NUM> is fixed and the upper platen <NUM> translates toward the lower platen <NUM> to close the press <NUM> and thereby secure a first polymer sheet (e.g., first polymer sheet <NUM>) to a second polymer sheet (e.g., the second polymer sheet <NUM>). According to the claimed invention, the fluid-filled chamber <NUM> is defined by coupling a first portion of the first sheet of material <NUM> to a second portion of the first sheet of material <NUM>. In other examples, the lower platen <NUM> and the upper platen <NUM> may each translate toward one another, or only the lower platen <NUM> may translate toward the upper platen <NUM>.

Securing the first polymer sheet <NUM> to the second polymer sheet <NUM> as in the configuration that does not form part of the claimed invention, or securing a first portion of the first sheet of material <NUM> to a second portion of the first sheet of material <NUM> as in the claimed invention, to form the peripheral bond <NUM> may be accomplished by heating, ultrasonically welding, RF welding, or otherwise applying an adhesive to the first polymer sheet <NUM> or the second polymer sheet <NUM>, such that the first polymer sheet <NUM>, or the first portion of the first sheet of material <NUM>, is melted, melded, bonded, adhered or otherwise secured or connected to the second polymer sheet <NUM>, or the second portion of the first sheet of material <NUM> in a substantially airtight or sealed manner. For example, as illustrated in <FIG>, the upper platen <NUM> or lower platen <NUM> may include one or more heating elements <NUM> disposed therein that selectively raise a temperature of the first surface <NUM> and/or the second surface <NUM>, respectively.

As will be described in more detail below, while in the closed position, in some implementations, the first and second surfaces <NUM> and <NUM> may apply sufficient heat and/or pressure for joining the first and second portion of the first sheet of material <NUM> or the first and second polymer sheets <NUM> and <NUM> together and, thus, defining the peripheral bond <NUM> of the fluid-filled chamber <NUM>. In some examples, that do not form part of the claimed invention, the first and second surfaces <NUM> and <NUM> may ultrasonically or RF weld the first polymer sheet <NUM> to the second polymer sheet <NUM> at the peripheral bond <NUM>. In some examples, the first and second surfaces <NUM> and <NUM> may cause the first polymer sheet <NUM> to bond to the second polymer sheet <NUM> in another manner. According to the claimed method, the fluid-filled chamber <NUM> is defined by coupling a first portion of a first sheet of material <NUM> to a second portion of the first sheet of material <NUM>.

In some configurations that do not form part of the claimed invention, the tensile element <NUM> defines a predetermined area <NUM> (<FIG>) and is operative to maintain a gap G between the polymer sheets <NUM> and <NUM> at the predetermined area <NUM> such that the sheets <NUM> and <NUM> only join together at locations outside of the predetermined area <NUM>. With reference to <FIG>, in other configurations, a jig <NUM> is positioned between the first surface <NUM> and the first polymer sheet <NUM> or between the second surface <NUM> and the second polymer sheet <NUM>, and the gap G between the sheets <NUM> and <NUM> is maintained within an interior void <NUM> defined by the jig <NUM>.

Referring to <FIG>, schematic views of the system <NUM> of <FIG> are provided and include the housing <NUM> (e.g. the upper portion <NUM> and the lower portion <NUM>) and the press <NUM> (e.g., the lower platen <NUM> and the upper platen <NUM>) operable between opened (e.g., <FIG>) and closed (e.g., <FIG>) positions for joining the first polymer sheet <NUM> to the second polymer sheet <NUM> to define the peripheral bond <NUM> of the fluid-filled chamber <NUM>, according to a not claimed example. As set forth above, once formed, the fluid-filled chamber <NUM> (e.g., <FIG>) may be incorporated into the article of footwear <NUM> of <FIG> and <FIG>. It will be appreciated, however, that the fluid-filled chamber <NUM> may be incorporated into other assemblies.

<FIG> shows the system <NUM> in a first exemplary mode of operation, during which (i) the upper portion <NUM> of the housing <NUM> is in an open position relative to the lower portion <NUM> of the housing <NUM>, and (ii) the upper platen <NUM> of the press <NUM> is in an open position relative to the lower platen <NUM> of the press <NUM>. During the first mode of operation, the pressure of the fluid inside the chamber <NUM> may equal the pressure of the fluid outside the chamber <NUM>. In this regard, the pressure gauge <NUM> may measure the value of the pressure of the fluid inside the chamber <NUM> to be substantially equal to the value of the atmospheric pressure of the atmosphere surrounding the housing <NUM>.

<FIG> shows the system <NUM> in a second exemplary mode of operation, that does not form part of the claimed invention, during which (i) the upper portion <NUM> of the housing <NUM> is in the open position relative to the lower portion <NUM> of the housing <NUM>, (ii) the upper platen <NUM> of the press <NUM> is in the open position relative to the lower platen <NUM> of the press <NUM>, (iii) the first polymer sheet <NUM> is positioned on or adjacent to the second surface <NUM> of the lower platen <NUM>, (iv) the second polymer sheet <NUM> is positioned on or adjacent to the first polymer sheet <NUM>, and (v) the tensile element <NUM> is disposed between the first polymer sheet <NUM> and the second polymer sheet <NUM>. In this regard, the tensile element <NUM> may maintain the gap G between the first polymer sheet <NUM> and the second polymer sheet <NUM> at the predetermined area <NUM> such that the first polymer sheet <NUM> and the second polymer sheet <NUM> are prevented from joining, or otherwise bonding, to one another at locations within the predetermined area <NUM>. As previously described, in other implementations, the gap G may be maintained utilizing other techniques, such as the jig <NUM>.

<FIG> shows the system <NUM> in a third exemplary mode of operation, during which (i) the upper portion <NUM> of the housing <NUM> is in a closed position relative to the lower portion <NUM> of the housing <NUM>, and (ii) the upper platen <NUM> of the press <NUM> is in the open position relative to the lower platen <NUM> of the press <NUM>. In particular, the upper portion <NUM> of the housing <NUM> may be sealed relative to the lower portion <NUM> of the housing <NUM> such that the housing <NUM> is sealed and the fluid within the chamber <NUM> is sealed relative to the fluid surrounding the chamber <NUM>.

<FIG> shows the system <NUM> in a fourth exemplary mode of operation, during which fluid is supplied to the chamber <NUM> from the first fluid supply system <NUM> or the second fluid supply system <NUM>. For example, fluid may be delivered to the chamber <NUM> from the first fluid source <NUM> via a bellows or other fluid-supply device. Accordingly, during the fourth mode of operation, the value of the pressure of the fluid within the chamber <NUM> and within the gap G formed between the polymer sheets <NUM> and <NUM> may be greater than the value of the pressure of the fluid outside the chamber <NUM>. In this regard, the pressure gauge <NUM> may measure the pressure of the fluid inside the chamber <NUM> to be greater than the atmospheric pressure of the atmosphere surrounding the housing <NUM>. For example, the pressure within the chamber <NUM> may be between <NUM> kPa and <NUM> kPa (<NUM> atm and <NUM> atm). In some implementations, the pressure within the chamber <NUM> may be substantially equal to <NUM> kPa (<NUM> atm).

<FIG> shows the system <NUM> in a fifth exemplary mode of operation, that does not form part of the claimed invention, during which (i) the upper portion <NUM> of the housing <NUM> is in the closed position relative to the lower portion <NUM> of the housing <NUM>, and (ii) the upper platen <NUM> of the press <NUM> is in a closed position relative to the lower platen <NUM> of the press <NUM>. During the fifth mode of operation, the first polymer sheet <NUM> may be secured to the second polymer sheet <NUM> at the peripheral bond <NUM> by heating, ultrasonically or RF welding, or otherwise applying an adhesive to the first polymer sheet <NUM> or the second polymer sheet <NUM>, as previously described, such that the first polymer sheet <NUM> is melted, melded, bonded, adhered or otherwise secured or connected to the second polymer sheet <NUM> in a substantially airtight or sealed manner. In this regard, during the fifth mode of operation, the fluid delivered to the chamber <NUM> during the fourth mode of operation may be sealed within the gap G during the fifth mode of operation to form a fluid-filled chamber (e.g., fluid-filled chamber <NUM>). Accordingly, the value of the pressure of the fluid within the chamber <NUM> and the gap G during the fifth mode of operation may be substantially equal to the value of the pressure of the fluid within the chamber and the gap G during the fourth mode of operation. In particular, the value of the pressure within the chamber <NUM> and the gap G during the fifth mode of operation may be greater than the value of the atmospheric pressure of the atmosphere surrounding the housing <NUM>.

<FIG> shows the system <NUM> in a sixth exemplary mode of operation, during which (i) the upper portion <NUM> of the housing <NUM> is in the closed position relative to the lower portion <NUM> of the housing <NUM>, and (ii) the upper platen <NUM> of the press <NUM> is in the open position relative to the lower platen <NUM> of the press <NUM>. During the sixth mode of operation, the pressure gauge <NUM> may measure the pressure of the fluid inside the chamber <NUM> to be greater than the atmospheric pressure of the atmosphere surrounding the housing <NUM>.

<FIG> shows the system in a seventh exemplary mode of operation, during which fluid may be released from the chamber <NUM>. For example, in some implementations, fluid is supplied from the chamber <NUM> to one of the first fluid supply system <NUM> and the second fluid supply system <NUM>. For example, fluid may be delivered to the first fluid source <NUM> via a bellows or other fluid-supply device from the chamber <NUM>. In other implementations, fluid is supplied from the chamber <NUM> to the atmosphere surrounding the chamber <NUM>. Accordingly, during the seventh mode of operation, the value of the pressure of the fluid within the chamber <NUM> may be less than or equal to the value of the pressure of the fluid outside the chamber <NUM>, while the value of the pressure of the fluid within the gap G (e.g., within the fluid-filled chamber <NUM>) may be greater than the value of the pressure of the fluid within the chamber <NUM> and the value of the pressure of the fluid outside the chamber <NUM>. In some implementations, the pressure gauge <NUM> may measure the pressure of the fluid inside the chamber <NUM> to be equal to the atmospheric pressure of the atmosphere surrounding the housing <NUM>.

In some implementations, during the seventh exemplary mode of operation, a negative pressure (e.g., a vacuum) may be applied to the chamber <NUM>. For example, during the seventh mode of operation, the first fluid supply system <NUM> or the second fluid supply system <NUM> may apply a vacuum to the chamber <NUM>. In particular, the bellows of the first fluid source <NUM> may apply a vacuum to the chamber <NUM> such that the value of the pressure of the fluid inside the chamber <NUM> is less than the value of the atmospheric pressure of the atmosphere surrounding the housing <NUM>. For example, the pressure within the chamber <NUM> may be between <NUM> kPa and <NUM> kPa (<NUM> atm and <NUM> atm). In some implementations, the pressure within the chamber <NUM> may be substantially equal to <NUM> kPa (<NUM> atm). Accordingly, the value of the pressure of the fluid within the fluid-filled chamber <NUM> and the value of the pressure of the fluid within the chamber <NUM> may cause the size of the fluid-filled chamber <NUM> to increase based on equation (<NUM>): <MAT> where P<NUM> and V<NUM> are the pressure and volume, respectively, of the fluid-filled chamber <NUM> during the fifth mode of operation, and P<NUM> and V<NUM> are the pressure and volume, respectively, of the fluid-filled chamber <NUM> during the sixth mode of operation.

As the pressure in the chamber <NUM> is reduced during the seventh exemplary mode of operation, the pressure of the fluid within the fluid-filled chamber <NUM> may increase the volume of the fluid-filled chamber <NUM> and stretch the first and second polymer sheets <NUM>, <NUM>, thereby proportionately reducing the pressure of the fluid within the fluid-filled chamber <NUM>. In some implementations, the volume of the fluid-filled chamber <NUM> may increase until the first and second polymer sheets <NUM>, <NUM> have stretched to their elastic limit and are limited from further expansion by the tensile element <NUM> if present. For example, the volume of the fluid-filled chamber <NUM> may increase such that the volume V<NUM> is between <NUM>% and <NUM>% of the volume V<NUM>. In some implementations, the volume V<NUM> is <NUM>% of the volume V<NUM>. If the tensile element <NUM> is present, the tensile element <NUM> does not need to be "shocked" before being inserted between the sheets <NUM>, <NUM>, as is often necessary during construction of a conventional fluid-filled chamber containing a tensile element due to the automatic expansion of the fluid-filled chamber <NUM> in response to the reduction of pressure acting on the fluid-filled chamber <NUM> when the pressure in the chamber <NUM> is reduced. Namely, the fibers or tensile elements <NUM> of the tensile element <NUM> do not need to be stretched or placed under tension prior to inflation of the fluid-filled chamber <NUM> (i.e., "shocked"), as the tensile elements <NUM> are automatically stretched and placed under tension when the pressure within the chamber <NUM> is reduced, as this expansion is rapid enough to obviate the need to first shock the fibers <NUM>.

<FIG> shows the system <NUM> in an eighth exemplary mode of operation, during which (i) the upper portion <NUM> of the housing <NUM> may be in the closed position relative to the lower portion <NUM> of the housing <NUM>, and (ii) the upper platen <NUM> of the press <NUM> is in the open position relative to the lower platen <NUM> of the press <NUM>. During the eighth mode of operation, fluid may be supplied to the chamber <NUM> from the atmosphere or from one of the first fluid supply system <NUM> or the second fluid supply system <NUM>. For example, fluid may be delivered to the chamber <NUM> from the second fluid source <NUM> via a bellows or other fluid-supply device. Accordingly, during the eighth mode of operation, the value of the pressure of the fluid within the chamber <NUM> may increase. In some implementations, fluid is delivered to the chamber <NUM> from the atmosphere surrounding the chamber <NUM>. Accordingly, the value of the pressure of the fluid within the chamber <NUM> may equal the value of the atmospheric pressure of the atmosphere surrounding the housing <NUM>. In this regard, the pressure gauge <NUM> may measure the pressure of the fluid inside the chamber <NUM> to be equal to the atmospheric pressure of the atmosphere surrounding the housing <NUM>. For example, the pressure within the chamber <NUM> may be between <NUM> kPa and <NUM> kPa (<NUM> atm and <NUM> atm). In some implementations, the pressure within the chamber <NUM> may be substantially equal to <NUM> kPa (<NUM> atm).

As the value of the pressure within the chamber <NUM> increases during the eighth mode of operation, the value of the pressure of the fluid within the fluid-filled chamber <NUM> and the value of the pressure of the fluid within the chamber <NUM> may cause the size of the fluid-filled chamber <NUM> to decrease based on equation (<NUM>). Namely, as the pressure in the chamber <NUM> increases during the eighth mode of operation, the volume of the fluid-filled chamber <NUM> may be reduced, thereby proportionately increasing the pressure of the fluid within the fluid-filled chamber <NUM>. In this regard, the pressure of the fluid within the fluid-filled chamber <NUM> may increase until the atmospheric pressure of the atmosphere surrounding the fluid-filled chamber <NUM> is equal to the value of the pressure within the fluid-filled chamber <NUM>.

<FIG> shows the system <NUM> in a ninth exemplary mode of operation, during which (i) the upper portion <NUM> of the housing <NUM> may be in the open position relative to the lower portion <NUM> of the housing <NUM>, and (ii) the upper platen <NUM> of the press <NUM> is in the open position relative to the lower platen <NUM> of the press <NUM>. During the ninth mode of operation, the fluid-filled chamber <NUM> may exit the housing <NUM> for assembly in an article of footwear (e.g., footwear <NUM>) or other article of manufacture.

With reference to <FIG>, a method of forming a fluid-filled chamber (e.g., chamber <NUM>, chamber <NUM>) begins at <NUM>. At step <NUM>, the method may include forming one or more sheets (e.g., sheet <NUM>, sheet <NUM>) of material. In some implementations, the sheets are formed in a lamination process. In particular, the sheets may be formed in a lamination welding process in which layers of material (e.g., TPU, or other polymer) are laminated to one another in an ultrasonic, RF, or other suitable welding process.

At step <NUM>, according to a not claimed example, the method may include locating one or more sheets (e.g., sheet <NUM>, sheet <NUM>) of material in a chamber (e.g., chamber <NUM>). For example, the sheets <NUM>, <NUM> may be transferred or otherwise moved between upper and lower platens (e.g., upper and lower platens <NUM>, <NUM>) of a press (e.g., press <NUM>). In some implementations, that do not form part of the claimed invention, a first polymer sheet (e.g., first polymer sheet <NUM>) is positioned on or adjacent to an upper surface (e.g., second surface <NUM>) of a lower platen, (iv) a second polymer sheet (e.g., second polymer sheet <NUM>) is positioned on or adjacent to the first polymer sheet, and (v) a tensile element (e.g., tensile element <NUM>) is disposed between the first polymer sheet and the second polymer sheet. According to the claimed invention, the method includes positioning one sheet (e.g., first sheet of material <NUM>) of material in a chamber (e.g., pressure chamber <NUM>).

At step <NUM>, the method may include sealing the chamber. For example, the method may include closing a first portion (e.g., upper portion <NUM>) of a housing (e.g., housing <NUM>) relative to a second portion (e.g., lower portion <NUM>) of the housing. In particular, at step <NUM>, the first portion of the housing may be sealed relative to the second portion of the housing such that the housing is sealed and the fluid within the chamber is sealed relative to the fluid surrounding the chamber.

At step <NUM>, the method may include supplying a fluid (e.g., nitrogen gas) to the chamber from a fluid supply system (e.g., first fluid supply system <NUM> or second fluid supply system <NUM>). For example, fluid may be delivered to the chamber from a first fluid source (e.g., first fluid source <NUM>) via a bellows or other fluid-supply device. Accordingly, at step <NUM>, the method may include increasing the fluid pressure within the chamber and within a gap (e.g., gap G) formed between the sheets. In particular, the fluid pressure within the chamber and the gap between the sheets at step <NUM> may be greater than the fluid pressure outside the chamber. For example, the pressure within the chamber at step <NUM> may be between <NUM> kPa and <NUM> kPa (<NUM> atm and <NUM> atm). In some implementations, the pressure within the chamber may be substantially equal to <NUM> kPa (<NUM> atm) at step <NUM>.

At step <NUM>, the method may include closing one of the upper or lower platen of the press relative to the lower platen of the press. In some implementations, the upper platen is closed relative to the other of the upper or lower platen such that fluid communication between the chamber and the gap formed between the sheets of material is prevented.

At step <NUM>, the method may include forming a fluid-filled chamber (e.g., fluid-filled chamber <NUM>). According to a not claimed example, the method may include securing the first sheet of material to the second sheet of material at a peripheral bond (e.g., peripheral bond <NUM>) by heating, ultrasonically or RF welding, or otherwise applying an adhesive to the first sheet of material or the second sheet of material, as previously described, such that the first sheet of material is melted, melded, bonded, adhered or otherwise secured or connected to the second sheet of material in a substantially airtight or sealed manner. According to the claimed invention, the fluid-filled chamber <NUM> is defined by coupling a first portion of the first sheet of material <NUM> to a second portion of the first sheet of material <NUM>. In this regard, at step <NUM>, the fluid delivered to the chamber at step <NUM> may be sealed within the gap formed between the sheets of material to define a fluid-filled chamber. The value of the pressure within the chamber and the gap during step <NUM> may be greater than the value of the atmospheric pressure of the atmosphere surrounding the housing.

At step <NUM>, the method may include opening one of the upper or lower platen of the press relative to the other of the upper or lower platen of the press. In some implementations, the upper platen is opened relative to the lower platen.

At step <NUM>, the method may include reducing a pressure within the chamber. For example, the method may include supplying, or otherwise releasing, a fluid from the chamber to one or more of the first fluid supply system, the second fluid supply system, or the atmosphere surrounding the chamber. In some implementations, fluid is supplied from the chamber to the first fluid supply system. For example, fluid may be delivered to the first fluid source via a bellows or other fluid-supply device from the chamber. Alternatively, or in addition thereto, fluid may be released from the chamber to the atmosphere surrounding the chamber. Accordingly, during step <NUM>, the fluid pressure within the chamber may be less than or equal to the fluid pressure outside the chamber, while the fluid pressure within the fluid-filled chamber formed by the sheets of material may be greater than the fluid pressure within the chamber and the fluid pressure outside the chamber. In this regard, during step <NUM>, the pressure gauge may measure the fluid pressure inside the chamber to be less than or equal to the atmospheric pressure of the atmosphere surrounding the housing.

In some implementations, during step <NUM>, a negative pressure (e.g., a vacuum) may be applied to the chamber. For example, the first fluid supply system or the second fluid supply system may apply a vacuum to the chamber such that the fluid pressure inside the chamber is less than the atmospheric pressure of the atmosphere surrounding the housing <NUM>. Accordingly, during step <NUM>, the value of the pressure of the fluid within the fluid-filled chamber defined by the sheets of material may cause the volume of the fluid-filled chamber to increase based on equation (<NUM>), where P<NUM> and V<NUM> are the pressure and volume, respectively, of the fluid-filled chamber during step <NUM>, and P<NUM> and V<NUM> are the pressure and volume, respectively, of the fluid-filled chamber during step <NUM>. As the pressure in the chamber decreases during step <NUM>, the pressure of the fluid within the fluid-filled chamber may increase the volume of the fluid-filled chamber and stretch the sheets of material, thereby proportionately reducing the pressure of the fluid within the fluid-filled chamber, thereby shocking the sheets of material.

At step <NUM>, the method may include supplying fluid to the chamber from the atmosphere or from one of the first fluid supply system or the second fluid supply system. For example, fluid may be delivered to the chamber from the second fluid source via a bellows or other fluid-supply device. Accordingly, during step <NUM>, the fluid pressure within the chamber may increase. In some implementations, fluid is delivered to the chamber from the atmosphere surrounding the chamber during step <NUM>. Accordingly, during step <NUM>, the fluid pressure within the chamber may equal the atmospheric pressure of the atmosphere surrounding the housing. In this regard, the pressure gauge may measure the pressure of the fluid inside the chamber to be equal to the atmospheric pressure of the atmosphere surrounding the housing.

As the value of the pressure within the chamber increases during step <NUM>, the value of the pressure of the fluid within the fluid-filled chamber and the value of the pressure of the fluid within the chamber may cause the volume of the gap fluid-filled chamber to decrease based on equation (<NUM>). Namely, as the pressure in the chamber increases during step <NUM>, the volume of the fluid-filled chamber may be reduced, thereby proportionately increasing the pressure of the fluid within the fluid-filled chamber. In this regard, the pressure of the fluid within the fluid-filled chamber may increase until the atmospheric pressure of the atmosphere surrounding the fluid-filled chamber is equal to the value of the pressure within the fluid-filled chamber.

Claim 1:
A method of forming a fluid-filled chamber (<NUM>) for an article of footwear (<NUM>), the method comprising:
positioning a first sheet of material (<NUM>) in a pressure chamber (<NUM>);
pressurizing the pressure chamber (<NUM>) to a fluid pressure equal to a first value;
forming a fluid-filled chamber (<NUM>) from the first sheet of material (<NUM>), the fluid-filled chamber (<NUM>) having a fluid pressure equal to the first value, wherein the fluid-filled chamber (<NUM>) is defined by coupling a first portion of the first sheet of material (<NUM>) to a second portion of the first sheet of material (<NUM>); and
depressurizing the pressure chamber (<NUM>) to reduce the fluid pressure within the pressure chamber (<NUM>) to a second value by applying a vacuum to the pressure chamber (<NUM>).