Patent Application
20120102782
Articles of footwear generally include two primary elements, an upper and a sole structure. The upper is formed from a variety of material elements (e.g., textiles, foam, leather, and synthetic leather) that are stitched or adhesively bonded together to form a void on the interior of the footwear for comfortably and securely receiving a foot. An ankle opening through the material elements provides access to the void, thereby facilitating entry and removal of the foot from the void. In addition, a lace is utilized to modify the dimensions of the void and secure the foot within the void.
The sole structure is located adjacent to a lower portion of the upper and is generally positioned between the foot and the ground. In many articles of footwear, including athletic footwear, the sole structure conventionally incorporates an insole, a midsole, and an outsole. The insole is a thin compressible member located within the void and adjacent to a lower surface of the void to enhance footwear comfort. The midsole, which may be secured to a lower surface of the upper and extends downward from the upper, forms a middle layer of the sole structure. In addition to attenuating ground reaction forces (i.e., providing cushioning for the foot), the midsole may limit foot motions or impart stability, for example. The outsole, which may be secured to a lower surface of the midsole, forms the ground-contacting portion of the footwear and is usually fashioned from a durable and wear-resistant material that includes texturing to improve traction.
The conventional midsole is primarily formed from a foamed polymer material, such as polyurethane or ethylvinylacetate, that extends throughout a length and width of the footwear. In some articles of footwear, the midsole may include a variety of additional footwear elements that enhance the comfort or performance of the footwear, including plates, moderators, fluid-filled chambers, lasting elements, or motion control members. In some configurations, any of these additional footwear elements may be located between the midsole and either of the upper and outsole, embedded within the midsole, or encapsulated by the foamed polymer material of the midsole, for example. Although many conventional midsoles are primarily formed from a foamed polymer material, fluid-filled chambers or other non-foam structures may form a majority of some midsole configurations.
A fluid-filled chamber, which may be incorporated into an article of footwear or a variety of other products, is disclosed below as having a barrier, a stacked tensile member, and a fluid. The barrier may be formed from a polymer material that is sealed to define an interior void. The stacked tensile member may be located within the interior void and includes a first tensile element and a second tensile element that are joined to each other. Additionally, opposite sides of the stacked tensile member are joined to the barrier. The fluid is located within the interior void and may be pressurized to place an outward force upon the barrier and induce tension in the stacked tensile member. In some configurations, each of the tensile elements may be a spacer textile.
A method of manufacturing a fluid-filled chamber is also disclosed below. The method includes securing a first tensile element to a second tensile element to form a stacked tensile member. The stacked tensile member is located between a first polymer layer and a second polymer layer. The first polymer layer is adjacent to a surface of the first tensile element, and the second polymer layer is adjacent to a surface of the second tensile element. Heat and pressure are applied to the first polymer layer, the second polymer layer, and the tensile member to bond (a) the first polymer layer to the surface of the first tensile element, (b) the second polymer layer to the surface of the second tensile element, and (c) the first polymer layer to the second polymer layer around a periphery of the stacked tensile member.
The advantages and features of novelty characterizing aspects of the invention are pointed out with particularity in the appended claims. To gain an improved understanding of the advantages and features of novelty, however, reference may be made to the following descriptive matter and accompanying figures that describe and illustrate various configurations and concepts related to the invention.
The foregoing Summary and the following Detailed Description will be better understood when read in conjunction with the accompanying figures.
The following discussion and accompanying figures disclose various configurations of fluid-filled chambers and methods for manufacturing the chambers. Although the chambers are disclosed with reference to footwear having a configuration that is suitable for running, concepts associated with the chambers may be applied to a wide range of athletic footwear styles, including basketball shoes, cross-training shoes, football shoes, golf shoes, hiking shoes and boots, ski and snowboarding boots, soccer shoes, tennis shoes, and walking shoes, for example. Concepts associated with the chambers may also be utilized with footwear styles that are generally considered to be non-athletic, including dress shoes, loafers, and sandals. In addition to footwear, the chambers may be incorporated into other types of apparel and athletic equipment, including helmets, gloves, and protective padding for sports such as football and hockey. Similar chambers may also be incorporated into cushions and other compressible structures utilized in household goods and industrial products. Accordingly, chambers incorporating the concepts disclosed herein may be utilized with a variety of products.
General Footwear Structure
An article of footwear 10 is depicted in
Upper 20 is depicted as having a substantially conventional configuration incorporating a plurality material elements (e.g., textile, foam, leather, and synthetic leather) that are stitched, adhered, bonded, or otherwise joined together to form an interior void for securely and comfortably receiving a foot. The material elements may be selected and located with respect to upper 20 in order to selectively impart properties of durability, air-permeability, wear-resistance, flexibility, and comfort, for example. An ankle opening 21 in heel region 13 provides access to the interior void. In addition, upper 20 may include a lace 22 that is utilized in a conventional manner to modify the dimensions of the interior void, thereby securing the foot within the interior void and facilitating entry and removal of the foot from the interior void. Lace 22 may extend through apertures in upper 20, and a tongue portion of upper 20 may extend between the interior void and lace 22. Upper 20 may also incorporate a sockliner 23 that is located with in the void in upper 20 and adjacent a plantar (i.e., lower) surface of the foot to enhance the comfort of footwear 10. Given that various aspects of the present application primarily relate to sole structure 30, upper 20 may exhibit the general configuration discussed above or the general configuration of practically any other conventional or non-conventional upper. Accordingly, the overall structure of upper 20 may vary significantly.
Sole structure 30 is secured to upper 20 and has a configuration that extends between upper 20 and the ground. In effect, therefore, sole structure 30 is located to extend between the foot and the ground. In addition to attenuating ground reaction forces (i.e., providing cushioning for the foot), sole structure 30 may provide traction, impart stability, and limit various foot motions, such as pronation. The primary elements of sole structure 30 are a midsole 31 and an outsole 32. Midsole 31 may be formed from a polymer foam material, such as polyurethane or ethylvinylacetate, that encapsulates a fluid-filled chamber 33. In addition to the polymer foam material and chamber 33, midsole 31 may incorporate one or more additional footwear elements that enhance the comfort, performance, or ground reaction force attenuation properties of footwear 10, including plates, moderators, lasting elements, or motion control members. Outsole 32, which may be absent in some configurations of footwear 10, is secured to a lower surface of midsole 31 and may be formed from a rubber material that provides a durable and wear-resistant surface for engaging the ground. In addition, outsole 32 may also be textured to enhance the traction (i.e., friction) properties between footwear 10 and the ground.
As incorporated into footwear 10, chamber 33 has a shape that fits within a perimeter of midsole 31 and is primarily located in heel region 13. When the foot is located within upper 20, chamber 33 extends under a heel area of the foot (i.e., under a calcaneus bone of the wearer) in order to attenuate ground reaction forces that are generated when sole structure 30 is compressed between the foot and the ground during various ambulatory activities, such as running and walking. In other configurations, chamber 33 may extend from forefoot region 11 to heel region 13 and also from lateral side 14 to medial side 15, thereby having a shape that corresponds with an outline of the foot and extends under substantially all of the foot. As depicted in
Although chamber 33 is depicted and discussed as being a sealed chamber within footwear 10, chamber 33 may also be a component of a fluid system within footwear 10. For example, pumps, conduits, and valves may be joined with chamber 33 to provide a fluid system that pressurizes chamber 33 with air from the exterior of footwear 10. More particularly, chamber 33 may be utilized in combination with any of the fluid systems disclosed in U.S. Pat. No. 7,210,249 to Passke, et al. and U.S. Pat. No. 7,409,779 to Dojan, et al.
Chamber Configuration
Chamber 33 is depicted individually in
Each of tensile elements 51 and 52 are spacer textiles (also referred to as a spacer-knit textiles) that include a pair of textile layers 53 a plurality of connecting members 54 extending between textile layers 53. That is, upper tensile element 51 includes two textile layers 53 with connecting members 54 extending therebetween, and lower tensile element 52 includes two more textile layers 53 with additional connecting members 54 extending therebetween. Whereas upper tensile element 51 is secured to an inner surface of upper barrier portion 41, lower tensile element 52 is secured to an inner surface of lower barrier portion 42. More particularly, one of textile layers 53 from upper tensile element 51 is secured to the inner surface of upper barrier portion 41, and one of textile layers 53 from lower tensile element 52 is secured to the inner surface of lower barrier portion 42. Additionally, centrally-located textile layers 53 from each of tensile members 51 and 52 are secured to each other, thereby joining tensile elements 51 and 52.
Textile layers 53 exhibit a generally continuous, planar, and parallel configuration. Connecting members 54 are secured to textile layers 53 and space textile layers 53 apart from each other. When incorporated into chamber 33, an outward force of the pressurized fluid places connecting members 54 in tension and restrains further outward movement of textile layers 53 and barrier portions 41 and 42. Connecting members 54 are arranged in rows that are separated by gaps. The use of gaps provides stacked tensile member 50 with increased compressibility in comparison to tensile members formed of double-walled fabrics that utilize continuous connecting members, although continuous connecting members 54 may be utilized in some configurations of chamber 33.
The lengths of connecting members 54 are substantially constant throughout stacked tensile member 50, which imparts the parallel configuration to each of textile layers 53. In some configurations, however, the lengths of connecting members 54 may vary to impart a contoured configuration to chamber 33. For example, chamber 33 may taper or may form a depression due to differences in the lengths of connecting members 54. Examples of contoured tensile members are disclosed in U.S. patent application Ser. No. 12/123,612 to Dua and Ser. No. 12/123,646 to Rapaport, et al. Each of tensile elements 51 and 52 may be cut or formed from a larger element of a spacer textile. Alternately, each of tensile elements 51 and 52 may be formed to have a variety of configurations through, for example, a flat-knitting process, as in U.S. patent application Ser. No. 12/123,612 to Dua.
In manufacturing chamber 33, a pair of polymer sheets may be molded and bonded during a thermoforming process to define barrier portions 41-43. More particularly, the thermoforming process (a) imparts shape to one of the polymer sheets in order to form upper barrier portion 41, (b) imparts shape to the other of the polymer sheets in order to form lower barrier portion 42 and sidewall barrier portion 43, and (c) forms a peripheral bond 44 that joins a periphery of the polymer sheets. Peripheral bond 44 is depicted as being adjacent to the upper surface of chamber 33, but may be positioned between the upper and lower surfaces or may be adjacent to the lower surface. The thermoforming process may also (a) locate stacked tensile member 50 within chamber 33 and (b) bond stacked tensile member 50 to each of barrier portions 41 and 42. Although substantially all of the thermoforming process may be performed with a mold, as described in greater detail below, each of the various parts or steps of the process may be performed separately in forming chamber 33. That is, a variety of other methods may be utilized to form chamber 33.
Following the thermoforming process, a fluid may be injected into the interior void and pressurized between zero and three-hundred-fifty kilopascals (i.e., approximately fifty-one pounds per square inch) or more. The pressurized fluid exerts an outward force upon chamber 33, which tends to separate barrier portions 41 and 42. Stacked tensile member 50, however, is secured to each of barrier portions 41 and 42 in order to retain the intended shape of chamber 33 when pressurized. More particularly, connecting members 53 extend across the interior void and are placed in tension by the outward force of the pressurized fluid upon barrier 40, thereby preventing barrier 40 from expanding outward and retaining the intended shape of chamber 33. Whereas peripheral bond 44 joins the polymer sheets to form a seal that prevents the fluid from escaping, stacked tensile member 50 prevents chamber 33 from expanding outward or otherwise distending due to the pressure of the fluid. That is, stacked tensile member 50 effectively limits the expansion of chamber 33 to retain an intended shape of surfaces of barrier portions 41 and 42. In addition to air and nitrogen, the fluid may include octafluorapropane or be any of the gasses disclosed in U.S. Pat. No. 4,340,626 to Rudy, such as hexafluoroethane and sulfur hexafluoride. In some configurations, chamber 33 may incorporate a valve or other structure that permits the pressure of the fluid to be adjusted.
A wide range of polymer materials may be utilized for barrier 40. In selecting a material for barrier 40, engineering properties of the material (e.g., tensile strength, stretch properties, fatigue characteristics, dynamic modulus, and loss tangent) as well as the ability of the material to prevent the diffusion of the fluid contained by barrier 40 may be considered. When formed of thermoplastic urethane, for example, barrier 40 may have a thickness of approximately 1.0 millimeter, but the thickness may range from 0.25 to 2.0 millimeters or more, for example. In addition to thermoplastic urethane, examples of polymer materials that may be suitable for chamber 33 include polyurethane, polyester, polyester polyurethane, and polyether polyurethane. Barrier 40 may also be formed from a material that includes alternating layers of thermoplastic polyurethane and ethylene-vinyl alcohol copolymer, as disclosed in U.S. Pat. Nos. 5,713,141 and 5,952,065 to Mitchell, et al. A variation upon this material may also be utilized, wherein a center layer is formed of ethylene-vinyl alcohol copolymer, layers adjacent to the center layer are formed of thermoplastic polyurethane, and outer layers are formed of a regrind material of thermoplastic polyurethane and ethylene-vinyl alcohol copolymer. Another suitable material for barrier 40 is a flexible microlayer membrane that includes alternating layers of a gas barrier material and an elastomeric material, as disclosed in U.S. Pat. Nos. 6,082,025 and 6,127,026 to Bonk, et al. Additional suitable materials are disclosed in U.S. Pat. Nos. 4,183,156 and 4,219,945 to Rudy. Further suitable materials include thermoplastic films containing a crystalline material, as disclosed in U.S. Pat. Nos. 4,936,029 and 5,042,176 to Rudy, and polyurethane including a polyester polyol, as disclosed in U.S. Pat. Nos. 6,013,340; 6,203,868; and 6,321,465 to Bonk, et al.
In order to facilitate bonding between stacked tensile member 50 and barrier 40, polymer supplemental layers may be applied to each of textile layers 53. When heated, the supplemental layers soften, melt, or otherwise begin to change state so that contact with barrier portions 41 and 42 induces material from each of barrier 40 and the supplemental layers to intermingle or otherwise join with each other. Upon cooling, therefore, the supplemental layers are permanently joined with barrier 40, thereby joining stacked tensile member 50 with barrier 40. In some configurations, thermoplastic threads or strips may be present within textile layers 53 to facilitate bonding with barrier 40, as disclosed in U.S. Pat. No. 7,070,845 to Thomas, et al., or an adhesive may be utilized to secure barrier 40 and tensile member 50. One or more polymer supplemental layers may also be utilized to join tensile elements 51 and 52 to each other, or an adhesive or stitching may be utilized. Accordingly, various techniques may be used to join stacked tensile member 50 to barrier 40 and to join tensile elements 51 and 52 to each other.
The overall configuration of chamber 33 discussed above provides an example of a suitable configuration for use in footwear 10. A variety of other configurations may, however, be utilized. As an example, each of tensile elements 51 and 52 are shown as having substantially identical thicknesses (e.g., 13 millimeters each), but may have different thicknesses, as depicted in
As discussed above, connecting members 54 are arranged in rows that are separated by gaps. Referring to
Based upon the above discussion, chamber 33 includes barrier 40, stacked tensile member 50, and a fluid (e.g., a pressurized fluid). Barrier 40 is formed from a polymer material that defines an interior void. Stacked tensile member 50 is located within the interior void. In one configuration, stacked tensile member 50 includes tensile elements 51 and 52 with the configuration of spacer textiles that overlap each other or exhibit a stacked configuration, but may have other configurations. Outward facing surfaces of tensile member 50 are joined to the polymer material of barrier 40. For example, the outward facing surface of upper tensile element 51 is joined to upper barrier portion 41, and the outward facing surface of lower tensile element 52 is joined to lower barrier portion 42. The fluid is located within the interior void and may be pressurized to place an outward force upon barrier 40 and induce tension in stacked tensile member 50.
Chamber 33 is discussed above as having a configuration that is suitable for footwear. In addition to footwear, chambers having similar configurations may be incorporated into other types of apparel and athletic equipment, including helmets, gloves, and protective padding for sports such as football and hockey. Similar chambers may also be incorporated into cushions and other compressible structures utilized in household goods and industrial products.
Manufacturing Process
Although a variety of manufacturing processes may be utilized to form chamber 33, an example of a suitable thermoforming process will now be discussed. With reference to
In preparation for the manufacturing process, various elements forming chamber 33 may be obtained and organized. For example, an upper polymer layer 71 and a lower polymer layer 72, which form barrier 40, may be cut to a desired shape, and two sections of a spacer textile (i.e., tensile elements 51 and 52) may be joined to form stacked tensile member 50. As discussed above, a supplemental layer of a polymer material may be utilized to join tensile elements 51 and 52. More particularly, the supplemental layer may be placed between tensile elements 51 and 52 and then heated, thereby inducing the polymer material to infiltrate the structures of textile layers 53. Upon cooling, tensile elements 51 and 52 are effectively joined together. As an alternative, an adhesive or stitching may be utilized to join tensile elements 51 and 52. At this stage, supplemental layers may also be applied to outward-facing textile layers 53 in order to ensure bonding with barrier 40 later in the manufacturing process. As a further matter, stacked tensile member 50 is in a compressed state at this stage of the manufacturing process, wherein textile layers 53 lay adjacent to each other and connecting members 54 are in a collapsed state. Upon completion of the manufacturing process, when chamber 33 is pressurized, stacked tensile member 50 is placed in tension, which spaces textile layers 53 from each other and induces connecting members 54 to straighten.
In manufacturing chamber 33, one or more of an upper polymer layer 71, a lower polymer layer 72, and stacked tensile member 50 are heated to a temperature that facilitates bonding between the components. Depending upon the specific materials utilized for stacked tensile member 50 and polymer layers 71 and 72, which form barrier 40, suitable temperatures may range from 120 to 200 degrees Celsius (248 to 392 degrees Fahrenheit) or more. Various radiant heaters or other devices may be utilized to heat the components of chamber 33. In some manufacturing processes, mold 60 may be heated such that contact between mold 60 and the components of chamber 33 raises the temperature of the components to a level that facilitates bonding.
Following heating, the components of chamber 33 are located between mold portions 61 and 62, as depicted in
At the stage depicted in
In order to provide a second means for drawing polymer layers 71 and 72 into contact with the various contours of mold 60, the area between polymer layers 71 and 72 and proximal tensile member 50 may be pressurized. During a preparatory stage of this method, an injection needle may be located between polymer layers 71 and 72, and the injection needle may be located such that ridges 64 envelop the injection needle when mold 60 closes. A gas may then be ejected from the injection needle such that polymer layers 71 and 72 engage ridges 64, thereby forming an inflation conduit 73 (see
As mold 60 closes further, ridges 64 bond upper polymer layer 71 to lower polymer layer 72, as depicted in
When bonding is complete, mold 60 is opened and chamber 33 and excess portions of polymer layers 71 and 72 are removed and permitted to cool, as depicted in
Further Configurations
A chamber 133 is depicted in
Each of tensile elements 151 and 152 are spacer textiles that include a pair of textile layers 153 a plurality of connecting members 154 extending between textile layers 153. That is, upper tensile element 151 includes two textile layers 153 with connecting members 154 extending therebetween, and lower tensile element 152 includes two more textile layers 153 with additional connecting members 154 extending therebetween. Whereas upper tensile element 151 is secured to an inner surface of upper barrier portion 141, lower tensile element 152 is secured to (a) the inner surface of upper barrier portion 141 and (b) an inner surface of lower barrier portion 142. More particularly, (a) one of textile layers 153 from upper tensile element 151 is secured to the inner surface of upper barrier portion 141, (b) one of textile layers 153 from lower tensile element 152 is secured to the inner surface of upper barrier portion 141, and (c) the other textile layer 153 from lower tensile element 152 is secured to the inner surface of lower barrier portion 142. Additionally, the centrally-located textile layers 153 from each of tensile members 151 and 152 are secured to each other, thereby joining tensile elements 151 and 152.
Based upon the above discussion, upper textile element 151 is secured to upper barrier portion 141, whereas lower textile element 152 is secured to both barrier portions 141 and 142. In order to impart this configuration, upper textile element 151 has lesser area than lower textile element 152. More particularly, upper textile element 151 is absent from a central area of chamber 133, whereas lower textile element 152 extends across both the central area and peripheral area of chamber 133. That is, upper textile element 151 has a U-shaped configuration that exposes central areas of lower textile element 152 and permits the central areas of lower textile element 152 to bond with upper barrier portion 141. Chamber 133 has a configuration wherein tensile elements 151 and 152 have different areas, which allows exposed areas to bond with both barrier portions 141 and 142 and imparts a contoured aspect to chamber 133. More particularly, this configuration forms a concave area in upper barrier portion 141, and may also form a concave area in lower barrier portion 142.
Chamber 33 exhibits a configuration wherein opposite surfaces have substantially planar configurations, at least in areas spaced inward from sidewall barrier portion 43. When incorporated into footwear 10, an upper surface of chamber 33, which is oriented to face upper 20, and a lower surface of chamber 33, which is oriented to face outsole 32, both exhibit the substantially planar configuration. As a result, the foot effectively rests upon a planar surface of chamber 33.
The manufacturing process for chamber 133 may be substantially similar to the manufacturing process for chamber 33 and may use mold 60. More particularly, the manufacturing process may involve (a) placing two polymer layers between mold portions 61 and 62, (b) locating tensile elements 151 and 152 between the polymer layers, (c) and compressing the components within mold 60 to bond the elements together. In contrast with the method discussed above for chamber 33, a method for manufacturing chamber 133 may also include bonding lower tensile element 152 to upper barrier portion 141. That is, the different sizes for tensile elements 151 and 152 will impart a configuration wherein lower tensile element 152 is also bonded to upper barrier portion 141.
Forming tensile elements 151 and 152 to have different areas or shapes may be utilized to impart a variety of contours to chamber 133 or other chambers. In further configurations, upper tensile element 151 may be located in the central area of chamber 133 and absent from the peripheral area of chamber 133 to impart a rounded or convex configuration to the upper surface, as depicted in
Forming chambers 133 with tensile elements 151 and 152 having different areas may induce edges of upper tensile element 151 to taper or curve toward lower tensile element 152. Referring to
Based upon the above discussion, chambers with various configurations may incorporate stacked tensile members. When tensile elements within the stacked tensile members have substantially equal areas, upper and lower surfaces of the chambers may exhibit planar and parallel surfaces. By varying the areas between the tensile elements, however, various contours or other features may be imparted to the chambers.
The invention is disclosed above and in the accompanying figures with reference to a variety of configurations. The purpose served by the disclosure, however, is to provide an example of the various features and concepts related to the invention, not to limit the scope of the invention. One skilled in the relevant art will recognize that numerous variations and modifications may be made to the configurations described above without departing from the scope of the present invention, as defined by the appended claims.
