Multi-piece upper for athletic footwear

In one embodiment, an article of footwear includes a sole and an upper attached to the sole. The upper and sole and configured to envelop at least a portion of human foot. The upper further includes a forefoot member attached to a forefoot portion of the sole and a heel member attached to a heel portion of the sole. The forefoot member and heel member are detached from each other at a location above the sole to enable individual adjustment of the forefoot member and the heel member.

TECHNICAL FIELD

The present disclosure relates generally to articles of footwear, and, more particularly, to uppers used in athletic footwear.

BACKGROUND

Footwear, particularly athletic footwear, is worn in a variety of activities including running, walking, hiking, other team and individual sports, and any activity where the protection and support of human feet is desired. In one configuration, an article of footwear includes a sole and an upper that form a cavity in which a user places his or her foot. The sole of the footwear engages the bottom of the foot and separates the foot from the ground. The sole often consists of one or more layers of materials including leather, rubber, foam, and plastics that provide shock absorption and support to the foot. The upper extends outwardly from an outer peripheral edge of the sole and covers at least a portion of the foot to hold the footwear in place. Uppers in athletic shoes are usually formed from one or more pieces of fabric, leather, and/or plastic that are stitched or otherwise attached together. Various fasteners including shoelaces and hook and loop fasteners are used to secure the foot in place within the footwear.

In an article of footwear, the sole provides cushioning and support for the foot and helps to maintain traction between the foot and the ground while running or walking. The sole deforms as the shape of the foot changes during each stride, and then returns to an undeformed configuration as the foot leaves the ground.

Proper engagement between the foot and the upper and sole of the shoe can improve the comfort and protection that the shoe provides to a wearer. The human foot has various sections including the forefoot, midfoot, and heel. During walking or running, the human foot transfers energy into the ground through the sole. Some mechanical energy is also stored in the sole as the sole deforms during a stride, and the mechanical energy is released as the foot and the sole leave the ground. Thus, improvements to footwear that enable each section of the foot to engage the footwear comfortably and improvements that reduce the effort needed to walk or run while wearing the footwear would be beneficial.

SUMMARY

In at least one embodiment, an article of footwear has been developed. The article of footwear includes a sole and an upper attached to the sole. The upper and sole are configured to envelop a human foot. The upper includes a forefoot member attached to a forefoot portion of the sole, and a heel member attached to a heel portion of the sole. The upper does not provide an attachment between the forefoot member and the heel member above the sole.

In at least one other embodiment, an article of footwear has been developed. The article of footwear includes a sole, a first upper member attached to the sole, a second upper member attached to the sole, and a shoe lace. The first upper member includes a first plurality of eyelets. The second upper member is detached from the first upper member apart from the sole. The second upper member includes a second plurality of eyelets configured to receive the shoelace. The shoe lace extends through the first plurality of eyelets and the second plurality of eyelets.

In at least one other embodiment, a method of producing an article of footwear has been developed. The method includes forming a forefoot member of an upper, forming a heel member of the upper, the heel member being separate from the forefoot member, engaging a sole member to the forefoot member and the heel member, attaching the forefoot member to the sole member without attaching the forefoot member to the heel member above the sole member, and attaching the heel member to the sole member without attaching the heel member to the forefoot member above the sole member.

In at least one other embodiment, a method for producing an article of footwear has been developed. The method includes forming a forefoot member of an upper on a forefoot portion of a last that is configured to conform to an approximate size and shape of a human foot, forming a heel member of an upper on a heel portion of the last, engaging a member of a sole to the last, the forefoot member, and the heel member, attaching the forefoot member to the sole, attaching the heel member to the sole, and removing the last from the forefoot member, heel member, and sole without attaching the forefoot member to the heel member above the sole.

The above described features and advantages, as well as others, will become more readily apparent to those of ordinary skill in the art by reference to the following detailed description and accompanying drawings. While it would be desirable to provide an apparatus that provides one or more of these or other advantageous features as may be apparent to those reviewing this disclosure, the teachings disclosed herein extend to those embodiments which fall within the scope of any appended claims, regardless of whether they include or accomplish one or more of the advantages or features mentioned herein.

DETAILED DESCRIPTION

For a general understanding of the details for the footwear disclosed herein, the drawings are referenced throughout this document. In the drawings, like reference numerals designate like elements. As used herein the term “foot” may refer to a portion of the human foot, a full human foot, and to the ankle. Various portions of the foot include, but are not limited to, the forefoot, midfoot, upper foot, heel, and ankle. As used in this document, the heel is considered to be the posterior end of the foot and the portion of an article of footwear that engages the heel is the posterior end of the article of footwear. The toes of the foot and toe-end of the article of footwear are considered to be the anterior ends of the foot and article of footwear, respectively. The terms “medial” and “medial side” refer to the inner side of a foot extending from the large toe to the heel, and the terms “lateral” and “lateral side” refer to the outer side of the foot extending from the small toe to the heel. Similarly, articles of footwear include medial and lateral sides that conform to the medial and lateral sides, respectively, of the foot. Some footwear embodiments include different contours on each of the medial and lateral sides to improve the fit of the footwear to the foot. The term “user” may refer to a person wearing an article of footwear.

The terms “forefoot” “midfoot” and “heel” as used herein with reference to an article of footwear refer to regions of the footwear configured to engage the forefoot, midfoot, and heel, respectively, of a human foot when a human wears the article of footwear. As used herein, and with reference toFIG. 12, the forefoot of a human foot includes the toes, which further include the phalanx bones1270. The midfoot is the region posterior from the forefoot that includes the metatarsal bones1260. The heel includes the posterior end of the foot including the calcaneus bone1240and talus bone1250. The list of bones recited above does not include every bone in the human foot, but is intended to provide references to a person having ordinary skill in the art for general identification of the forefoot, midfoot, and heel regions in a human foot and corresponding components in an article of footwear.

Various articles of footwear may engage only portions of each section of the foot. For example, a low-top athletic shoe may not engage portions of the heel including the calcaneus bone1240and talus bone1250, or an open-toed shoe may not directly engage each of the phalanges1270in the toes of the wearer.FIG. 12depicts a prior art article of footwear1200with a skeletal view of a human foot1204positioned in the footwear1200. The foot1204includes a heel1212, midfoot1216, and forefoot1220. The footwear1200includes an upper1208, depicted in dashed lines, and a sole1210. The upper1208and sole1210include a heel region1224, midfoot region1228and forefoot region1232that engage the heel1212, midfoot1216, and forefoot1220of the foot1204, respectively.FIG. 12does not depict precise boundaries between the various regions of the foot and a corresponding article of footwear, but instead depicts general regions of the footwear1200and human foot1204. In particular, the anterior end of the heel region1212and the posterior end of the midfoot region1216can be referred to as portions of either a heel or midfoot region interchangeably. Various footwear embodiments include gradual transitions between the heel region1224, midfoot region1228, and forefoot region1232. As described in more detail below, a single section of the shoe may engage more than one portion of the foot. For example, a sole of the shoe can engage an entire ventral portion of the human foot. A forefoot section of the upper of a shoe can engage some or all of the sides and dorsal (top) surface of the forefoot and midfoot, and a heel section of the upper can engage some or all of the sides of the heel and sides and dorsal surface of the midfoot.

General Arrangement of the Article of Footwear

FIG. 1-FIG.6depict different views of one embodiment of footwear, shown as an athletic shoe100that is configured to be worn on a left human foot. The athletic shoe100includes a sole132and an upper114formed from a heel member104and forefoot member120. In the upper114, the heel member104covers at least a portion of the heel region and midfoot region of the athletic shoe100, and the forefoot member120covers at least a portion of the forefoot region and midfoot region of the athletic shoe100. The athletic shoe100has a length depicted along axis101and a width depicted along axis102. The sole132, heel member104, and forefoot member120form a foot cavity140with an opening formed by the heel member104and a tongue126that is attached to the forefoot member120. A user inserts his or her foot into the foot cavity140when putting on the shoe, with the toes and forefoot moving forward in the foot cavity140to engage the forefoot member120, while the heel and a portion of the midfoot engage the heel member104. In the embodiment of the athletic shoe100, an insole144positioned at the top of the sole132engages the bottom of the foot in the foot cavity140. The heel member104, forefoot member120cover at least a portion of the top, sides, and posterior of the foot in the foot cavity140to hold the athletic shoe firmly in place on the foot. The sole132covers the bottom of the foot in the foot cavity to provide support and cushioning to the foot while the user wears the athletic shoe100. The upper114and the sole132envelop the human foot and provide protection and support for the human foot in the foot cavity140during a wide range of activities including athletic activities. As used herein, the term “envelop” refers to a complete or substantially complete enclosure of a human foot, allowing for a possible exception of an insubstantial portion of the foot not being covered, such as a small region below the ankle or other insubstantial uncovered portion. Accordingly, most convention running shoes would envelop the human foot while conventional sandals would not envelop the human foot.

ReferringFIG. 1, the upper114is depicted along the length101of the athletic shoe100. The forefoot member120is attached to the sole132and extends from the forefoot of the shoe100through a portion of the midfoot. The heel member104is attached to the sole132and extends from the heel of the shoe100to the midfoot. In the athletic shoe100, a portion of the forefoot member120and heel member104overlap in the midfoot region. The heel member104is positioned on the exterior of the forefoot member120in this overlapping region.FIG. 1depicts a medial leading edge108and lateral leading edge110of the heel member104. The forefoot member120extends past the medial leading edge108and lateral leading edge110of the heel member104toward the heel of the athletic shoe100, and the heel member104covers the forefoot member120in the overlapping region of the upper114.

The heel upper114is typically formed from one or more layers of various materials including fabrics, natural or synthetic leather, natural and synthetic rubber, foams, and plastics. In the athletic shoe100, the heel member104includes a posterior cushioning member112that engages the posterior of the heel and includes a fabric layer covering a foam layer that cushions the foot. Various types of synthetic fabric including nylon, polytetrafluoroethylene (sold commercially as Gore-Tex®), and HeatGear®, sold by Under Armour, Inc. of Baltimore, Md., can be used in forming the upper members104and120. The heel member104and forefoot member120can also include rigid or semi-rigid components such as thermoplastic or metal supports that resist bending and provide support to the foot.

The forefoot member120also includes a stretchable fabric section122which stretches to accommodate insertion of a foot into the foot cavity144and conforms to the top and sides of the foot in the foot cavity144. The stretchable fabric section122can be formed from various materials including elastane fabric. In the athletic shoe100, the overlap of the heel member104over the forefoot member120leaves a portion of the stretchable fabric122exposed on the lateral side of the athletic shoe100as depicted inFIG. 3, while the heel member104fully covers the stretchable fabric122on the medial side of the athletic shoe100, as depicted inFIG. 2. Other embodiments include larger or smaller sections of stretchable fabric, or can omit the stretchable fabric.

The forefoot member includes a tongue126. In the embodiment of the athletic shoe100, the tongue126is attached to the forefoot member120around substantially the entire anterior side, lateral side, and medial side of the tongue126, which are depicted with broken line128inFIG. 4andFIG. 11. At least a portion of the sides of the tongue128are attached to the stretchable fabric122in the forefoot member120. In the example of the athletic shoe100, the tongue126is stitched to the forefoot member120around the outer perimeter128, but in other embodiments the tongue is adhered to the forefoot member or formed from an integral piece of material that forms the forefoot member120. The stretchable fabric122enables adjustment of the tongue126to improve the fit of the athletic shoe100, even though the sides of the tongue126are attached to the forefoot member120. In alternative embodiments, the tongue126is attached to the forefoot member120along the anterior side of the tongue126and is substantially detached from the forefoot member120along the medial and lateral sides.

Both the heel member104and forefoot member120include eyelets that accept a single shoe lace130that laces the heel member104and forefoot member120together in the athletic shoe100. In the embodiment ofFIG. 1, the forefoot member includes a plurality of eyelets124formed from fabric loops that are positioned on the lateral and medial sides of the tongue126. The heel member104includes eyelet holes106that are formed through the material of the heel upper104. As used herein the term “eyelet” refers to any suitable structure for engaging a shoe lace to an article of footwear. Examples of other eyelet embodiments include hooks and tubular engagement members that accept the shoe lace.

The sole132further includes multiple members that support the bottom of a foot placed in the foot cavity140. As depicted inFIG. 9andFIG. 11, the sole132includes a midsole board148, resilient layer154, energy return plate160and treads152.FIG. 9also depicts a cushioning insole layer144that is positioned above the midsole board148. In the article of athletic shoe100, the midsole board148is attached to both the heel member104and forefoot member120in the upper114. Various alternative embodiments of the sole132include additional layers or omit some of the layers described herein.

FIG. 2andFIG. 3depict the medial and lateral sides, respectively, of the shoe100.FIG. 2andFIG. 3depict the sole132including a welt138. The welt138in the athletic shoe100is a black plastic member that is an integral member of the sole132that extends upward to provide a surface to attach both the heel member104and forefoot member120to the sole132. The welt138extends upward around a perimeter of the sole132depicted as dashed line136. Alternative footwear embodiments omit the welt and attach the forefoot and heel members to other layers of the sole132directly.

Separate Heel and Forefoot Members

As described above, the heel member104and forefoot member120are directly attached to one another along a common length116of the sole132, which common length116is directly below the overlapping region of the forefoot member120and heel member104in the upper114, as best depicted inFIG. 4andFIG. 11. Notwithstanding this overlap, the heel member104is separate from the forefoot member420above the sole132such that the upper114does not provide an attachment between the heel member104and the forefoot member120. In one configuration, the forefoot member120is strobled or sewn to the sole132first, and the heel member104is then strobled or sewn to the sole132after the forefoot member, with the overlapping portions of the heel member104being strobled to the sole132through a portion of the forefoot member120along common length116. Thus, in the athletic shoe100, the heel member104and forefoot member120are both attached to the midsole board148along a common length116of the sole132on the medial and lateral sides of the sole132. However, the heel member104and forefoot member120are separated from each other above the sole132. Nevertheless, some overlap between the heel member104and the forefoot member120generally occurs above the sole132. As depicted inFIG. 9andFIG. 11, the forefoot member120is attached to the midsole board148and the heel member104overlaps the forefoot member120. The strobling process forms stitches through the heel member104, forefoot member120, and the midsole board148to attach the heel member104and forefoot member120to the sole132along the common length116of the sole132. In other embodiments, the heel member104and forefoot member120are attached to the sole132via adhesives or other fastening means.

When worn on a foot, the shoelace130laces through eyelets124and106in both the forefoot member120and heel member104. The upper114does not, however, provide any attachment between the forefoot member120and the heel member104other than the common length116of the sole132where the heel member104and forefoot member120are attached to the sole132. More specifically, the heel member104is not sewn, adhered, or otherwise affixed to the forefoot member120above the sole132, thus enabling the heel member104to be moved independent of the forefoot member120as depicted inFIG. 4. The shoelace130engages the heel member104and the forefoot member120. However, because of the separation between the heel member104and forefoot member120, the heel member104and forefoot member120can be adjusted independently of one another.

The separate configuration of the forefoot member120and the heel member104in the upper114enables each section of the upper to be adjusted to different parts of a foot individually to improve the fit of the athletic shoe100. For example, the wearer can pull on the tongue126to fit the forefoot member120to the forefoot and midfoot while the fit of the heel member104remains substantially unchanged. Similarly, adjustments to the heel member104do not substantially affect the separate forefoot member120. When adjusting the shoelace130, the wearer can selectively loosen or tighten the portions of the shoe lace extending through the eyelets106to adjust the fit of the heel member104, or loosen or tighten portions of the shoe lace130extending through the eyelets124to adjust the fit of the forefoot member120.

The athletic shoe100shown inFIGS. 1-4is one example of an article of footwear with separated heel and forefoot members, but it will be recognized that other embodiments are also envisioned. In one alternative embodiment, the heel member104is attached to the sole132and a portion of the forefoot member120overlaps a portion of the heel member104(instead of the heel member104overlapping the forefoot member120as shown inFIGS. 1-4). In another alternative embodiment, the heel member104and forefoot member120do not overlap on the upper114or the sole132, but are instead attached to separate sections of the perimeter136around the sole132. In still another alternative embodiment, the heel member104and forefoot member120are attached together above the sole for only a fraction of a height of the two upper members. In one alternative configuration, the heel member104is attached to the forefoot member120near the medial and lateral leading edges108and110for a few centimeters or less of a height103of the heel member104extending upward from the sole132. Sufficient portions of the partially attached heel member104and forefoot member120remain detached and overlap each other to enable individual adjustment of the heel member104and forefoot member120to fit the foot inserted into the foot cavity140.

Method of Making the Article of Footwear

FIG. 7depicts a process700for producing an article of footwear. The athletic shoe100described above is one example of an article of footwear that can be produced using process700, and is described with process700for illustrative purposes. Process700begins by assembling the heel member104and forefoot member120as two separate pieces (block704). The heel and forefoot members can be assembled concurrently or at different times as needed. In one embodiment of process700, the tongue126is attached to the forefoot member120as part of the assembly of the forefoot member120. Various assembly methods known to the art including sewing and adhesion of the various components in each of the heel and forefoot uppers are used to assemble both of the forefoot and upper members. As depicted inFIG. 11, the heel member104and forefoot member120of the upper114are assembled as separate pieces. However, during the process700, the heel member104and forefoot member120do not take the shape depicted in the assembled athletic shoe100illustrated inFIG. 1-FIG.5until engaged with a last as described below.

After assembly, the separate heel and forefoot members lack the shape of an upper in a completed article of footwear. Both the heel member and the forefoot member engage a last that shapes the forefoot and heel members (block708). A last is a form having a size and shape approximating a size and shape of the foot cavity140in the athletic shoe100. In common manufacturing processes, a last is a shaped plastic or wood form. The heel member104and forefoot member120are stretched over the last in the shape of the upper in the athletic shoe100. Some process embodiments also heat the heel and forefoot members as the members are stretched over the last to form the shape of the upper in the completed athletic shoe. The forefoot member120engages a forefoot end of the last and stretches toward the heel. The heel member104engages a heel end of the last and stretches toward the forefoot. The heel member104and forefoot member120engage the last separately and are not attached to each other. In the embodiment of athletic shoe100, a portion of the heel member104overlaps a portion of the forefoot member120in the midfoot region of the last.

After forming the heel and forefoot members on the last, the forefoot member is attached to a member of the sole (block712). Some manufacturing processes attach the forefoot member to a midsole board, such as midsole board148in the sole132, which is typically a cardboard or polymer member that conforms to the shape of the sole. The midsole board is positioned on the bottom of the last and the forefoot member is strobled or otherwise attached to the midsole board. In shoes that employ a welt to attach the forefoot member to the sole, the welt is attached to the midsole board and then the forefoot member is attached to the welt. In some embodiments, the midsole board is integrated with other layers in the sole prior to attaching the forefoot member to the midsole board. In other embodiments, the remaining layers of the sole are attached to the midsole board after both the forefoot and heel members of the upper are attached to the midsole board. Some articles of footwear do include a midsole board. Process700attaches the upper forefoot member to another one of the layers of the sole for articles of footwear that omit the midsole board.

Process700continues by attaching the heel member to a member of the sole (block716). The heel member is attached to the sole member in a similar manner to the forefoot member. In the example of the athletic shoe100, one embodiment of process700attaches the heel member104to the sole member such as the midsole board or another layer of the sole after attaching the forefoot member120to the sole member. The heel member104is attached after the forefoot member120due to the overlap of the heel member104outside of a portion of the forefoot member120. In alternative embodiments, the forefoot member120is attached after the heel member104, or the two members are attached simultaneously. In each alternative embodiment, the forefoot member120and the heel member104are attached to the sole member132without attaching the forefoot member120and the heel member104above the sole member132.

After both the forefoot and heel members are attached to a member of the sole, the last is removed from the article of footwear (block720). In the athletic shoe100, the heel member104, forefoot member120, and sole132form the foot cavity140that accommodates a foot having a size and shape similar to the last.

Energy Return Plate

In at least one embodiment, the athletic shoe100includes an energy return plate160integrated within the sole132in the athletic shoe100. With reference toFIG. 8A, the energy return plate160includes a central portion162, medial forefoot arm164, lateral forefoot arm166, medial heel arm168, and lateral heel arm170. In one alternative embodiment depicted inFIG. 8B, an energy return plate190includes a central portion192, medial forefoot arm194, lateral forefoot arm196, and a heel arm198. During a stride of a human wearing the shoe100, the energy return plate deforms and absorbs mechanical energy from the stride. As the foot and athletic shoe100leave the ground, the energy return plate returns to an un-deformed configuration and returns some of the mechanical energy to the foot. The energy return plate is also referred to as a “spring plate” because the energy return plate includes multiple leaf spring members that store mechanical energy from various regions of the foot during a stride. It will be recognized that although the energy return plate160is described herein in association with the athletic shoe100having a separate heel member104and forefoot member120in the upper114, in other embodiments the energy return plate160could be incorporated into a shoe with a conventional or differently constructed upper114.

With particular reference toFIG. 8A, the medial forefoot arm164extends from the central portion162along the length of the medial side of the foot cavity to an area of the forefoot region proximate to the hallux (big toe). The lateral forefoot arm166extends from the central portion162along the length of the lateral side of the foot cavity to an area of the forefoot region proximate the fifth toe (little toe). Each of the medial and lateral forefoot arms164and166can extend under multiple toes and other regions of the forefoot and midfoot in the foot cavity based on the length and width selected for each arm. The medial heel arm168extends in the posterior direction from the central portion162toward the heel region along the medial side of the foot cavity and the lateral heel arm170extends in the posterior direction from the central portion along the lateral side of the foot cavity. The arms164,166,168, and170have an upward curvature near the distal end of each arm to conform to the sole and the foot. In the embodiment ofFIG. 8A, the energy return plate160is formed from a single plate of a carbon fiber reinforced polymer, but other embodiments can be formed from one or more resilient materials, including polymers and metals, and can be formed from multiple pieces.

In the energy return plate160ofFIG. 8A, the arms164,166,168, and170form an “H” shaped configuration with the central portion162forming the horizontal member of the “H”. Each of the arms164,166,168, and170has two ends with one end integrally formed with the central portion162, and the other end being free to move independently from the other arms in the energy return plate160. The configuration of the energy return plate160is cantilevered since each of the arms164-170is connected to the central portion162and the other arms at only one end. Each of the arms164-170is a leaf spring that is configured to deform and store mechanical energy when the athletic shoe100contacts the ground during a stride and to return at least some of the mechanical energy to the foot as the athletic shoe100leaves the ground.

FIG. 6andFIG. 9depict the energy return plate160in the sole132of the athletic shoe100.FIG. 6depicts the outline of the energy return plate160incorporated into the sole132. The sole132fully encloses the energy return plate160, which extends along the length of the sole132in parallel with the length of the foot cavity140. In the athletic shoe100, the central portion162of the energy return plate160is positioned posterior to the forefoot region under a portion of the foot cavity where the midfoot meets the heel. In alternative configurations, the central portion162can be positioned farther in the anterior direction under the midfoot region or farther in the posterior direction under the heel region. The configuration of the forefoot and heel arms in the energy return plate160is asymmetrical along the length101of the athletic shoe100. For example, the medial forefoot arm164extends further toward the forefoot end of the athletic shoe100than the lateral forefoot arm166. Additionally, the medial forefoot arm164includes a bulge172that increases the rigidity of the medial forefoot arm164near the central portion162. In the embodiment of the energy return plate160used in the athletic shoe100, the lateral heel arm170extends in the posterior direction under the heel farther than the medial heel arm168. The shapes, curvatures, and sizes of each arm in the energy return plate160can be varied to fit various footwear designs.

FIG. 9depicts various layers in the sole132in more detail in a cross-sectional view of a selected portion of the athletic shoe100taken along line180. The sole132depicted inFIG. 9is exemplary of one configuration that incorporates an energy return plate. The sole132includes treads152, a resilient layer154that is joined with a transparent polymer156, the energy return plate160, the midsole board148, and an insole layer144. The resilient layer154and treads152are referred to as outsole layers that form portions of the exterior of the sole132. Different designs of soles can include a larger or lesser number of layers in the outsole and can be formed from various combinations of materials. The treads152engage the ground when the athletic shoe100is worn and are typically formed from vulcanized rubber. The treads152are positioned and shaped to provide a firm grip between the athletic shoe100and the ground during a stride.

The resilient layer154provides structural support for the sole132and engages the treads152and a bottom side of the energy return plate160. The resilient layer154can be formed from various materials including vulcanized rubber and polyurethane foam. The design of the athletic shoe100optionally includes a transparent polymer layer156that is co-planar with portions of the resilient layer154. The transparent polymer layer156encloses the energy return plate160in areas where the resilient layer154does not extend across the entire width of the sole132. The transparent polymer layer156visually exposes portions of the energy return plate160for aesthetic purposes, and seals the energy return plate from dirt or other contaminants that contact the sole132. Other embodiments of the athletic shoe100omit the transparent polymer layer156and include a resilient layer154that covers the bottom side of the energy return plate160.

The midsole board148engages the resilient layer154and a top side of the energy return plate160. The midsole board148is also attached to the welt138, heel member104and forefoot member120as described above. The insole layer144is positioned over the midsole board148and forms the bottom of the foot cavity140in the athletic shoe100. The insole layer144provides support, cushioning, and shock absorption for the foot and is typically formed from one or more layers of compression foam, silicone gels, or other cushioning materials. In some embodiments the insole layer144can be removed from the athletic shoe100and replaced with a different insole.

FIG. 8Bdepicts an alternative energy return plate190. The energy return plate190includes a single central portion192that extends in the posterior direction to a heel end198. A medial forefoot arm194and lateral forefoot arm196extend from the central portion192along the medial and lateral sides of the foot cavity under the midfoot and forefoot regions of the foot. In the energy return plate190, both the medial and lateral forefoot arms include a plurality of indentations200formed through the top side of the energy return plate190. The indentations200enable a uniform deformation of both the medial and lateral forefoot arms194and196, respectively, during a stride. Different embodiments of the energy return plates190and160optionally include one or more indentations in both the forefoot and heel arms. The indentations200are arranged transverse to the length of the foot cavity101to accommodate deformation of either or both of the medial and lateral forefoot arms194and196during a stride. The medial and lateral forefoot arms are asymmetric in the embodiment of the energy return plate190with a bulge202that increases the rigidity of the medial forefoot arm194near the central portion192. The energy return plate190is incorporated into the sole of an article of footwear in a similar manner to the energy return plate160depicted above.

The energy return plate190is formed in a “Y” shaped configuration, with the forefoot arms194and196forming the forked members of the “Y” and the central portion192and the central portion192forming the base of the “Y” shape. The forefoot arms are both connected at only one end to the central portion192in a cantilevered configuration. The central portion192also serves as a single heel arm extending under the heel region of a foot in the athletic shoe100. The arms194and196and the central portion192are each a leaf spring that is configured to deform and store mechanical energy when the athletic shoe100contacts the ground during a stride and to return at least some of the mechanical energy to the foot as the athletic shoe100leaves the ground.

FIG. 10Adepicts the energy return plate160in isolation when the athletic shoe160lies flat on surface such as the ground. InFIG. 10A, the forefoot arms164and162(hidden behind forefoot arm164inFIG. 10A) and heel arm168and170are each in an un-deformed position with no biasing force applied to the energy return plate160. During a stride, each of the arms164-170deforms to absorb mechanical energy from the stride, and then return at least a portion of the mechanical energy when the energy return plate returns to the un-deformed configuration.

FIG. 10Bdepicts the energy return plate160in isolation during a pronated stride. A pronated stride occurs when the heel initially contacts the ground on the lateral side of the foot and then rolls inwards toward the medial side of the foot during the stride. During a pronated stride, the foot places an uneven force on the medial and lateral sides of the energy return plate160. The medial forefoot arm164and medial heel arm168of the energy return plate deform at a somewhat greater rate than the lateral forefoot arm166and lateral heel arm170in the energy return plate160in response to the force of the foot. Since the foot angles inward toward the medial side during a pronated stride, the medial forefoot arm164and medial heel arm168are positioned at a lower level than the lateral forefoot arm166and lateral heel arm170.

The cantilevered configuration of the forefoot arms164and166enables the medial forefoot arm164to deform to a greater degree than the lateral forefoot arm166since the forefoot ends of both arms are free ends that are only connected to each other through the central portion162. The cantilevered configuration of the heel arms168and170enables the heel arm168to deform to a greater degree than the lateral heel arm170as well. Both the medial and lateral sides of the energy return plate160experience some deformation as depicted inFIG. 10B. As the athletic shoe100leaves the ground, the energy return plate160and sole132return to an un-deformed configuration and energy stored in the energy return plate urges the athletic shoe100and the foot of the wearer upward as the foot lifts during the stride.

FIG. 10Cdepicts the energy return plate160in isolation during a supinated stride. In a supinated stride, the heel initially contacts the ground on the lateral side and then does not roll inwardly toward the medial side by a significant amount during the stride. During a supinated stride, the foot places an uneven force on the medial and lateral sides of the energy return plate160with a different distribution of force than in the pronated stride. The lateral forefoot arm166and lateral heel arm170deform at a somewhat greater rate than the medial forefoot arm164and medial heel arm168in the energy return plate160in response to the force of the foot.

Since the lateral side of the foot experiences a greater force during the supinated stride, the medial forefoot arm164and medial heel arm168are positioned at a higher level than the lateral forefoot arm166and lateral heel arm170. Both the medial and lateral sides of the energy return plate160experience some deformation as depicted inFIG. 10C. The cantilevered configuration of the arms166-170in the energy return plate160enables the lateral forefoot arm166and lateral heel arm170to deform to a greater degree than the corresponding medial forefoot arm164and medial heel arm168. As the athletic shoe100leaves the ground, the energy return plate160and sole132return to an un-deformed configuration and energy stored in the energy return plate urges the athletic shoe100and the foot of the wearer upward as the foot lifts during the stride.

WhileFIG. 10BandFIG. 10Cdepict the energy return plate160during pronated and supinated strides, respectively, another form of stride has “neutral” pronation in which the force of the stride is distributed approximately evenly between the medial and lateral arms of the energy return plate160. The medial and lateral arms in the energy return plate160deform by approximately equal amounts during a neutrally pronated stride.

The upward force from the energy return plate160is also referred to as a “rebound” force, and the rebound force reduces the energy and effort needed to lift the foot during the next stride. The configuration of the energy return plates160and190enable the athletic shoe100to deliver a rebound force evenly across the foot and to accommodate wearers with both pronated and supinated strides.

The energy return plate embodiments described above provide several advantages to a person wearing the athletic shoe100. First, the energy return plates extend for substantially the entire length of the foot extending from under the heel to under some or all of the toes of the foot in the foot cavity. The length of the energy plate enables the energy plate to store more mechanical energy for release as the athletic shoe leaves the ground during a stride. Second, the energy return plate provides return energy to both the medial and lateral sides of the foot. Third, the asymmetric configuration of the energy return plate accommodates wearers who have both pronated and supinated strides.

Although the present invention has been described with respect to certain preferred embodiments, it will be appreciated by those of skill in the art that other implementations and adaptations are possible. Moreover, there are advantages to individual advancements described herein that may be obtained without incorporating other aspects described above. Therefore, the spirit and scope of any appended claims should not be limited to the description of the preferred embodiments contained herein.