Conventional articles of footwear generally include two primary components: an upper and a sole structure. The upper provides a covering for the foot and securely positions the foot relative to the sole structure. The sole structure is secured to a lower surface of the upper and configured so as to be positioned between the foot and the ground when a wearer is standing, walking or running. Sole structures are often designed so as to cushion, protect and support the foot. Sole structures may also be designed so as to increase traction and to help control potentially harmful foot motion such as overpronation.
Many types of athletic footwear have a sole structure that includes a deformable midsole. A primary element of many conventional midsoles is a resilient polymer foam material that extends throughout the length of the footwear. The physical characteristics of a midsole often depend on the density and other properties of the polymer foam material and on the dimensional configuration of the midsole. By varying these factors throughout the midsole, the relative stiffness, degree of ground reaction force attenuation, and energy absorption properties may be altered to meet the specific demands of the activity for which the footwear is intended to be used.
Cushioning and impact attenuation are valuable attributes of a sole structure. However, components that provide these attributes also tend to reduce the degree to which a shoe wearer can sense ground contours and other features. This loss of sensation regarding ground features can be disadvantageous. The feel of a ground surface sensed by the underside of a person's foot can provide useful cues regarding conditions of the ground over which that person may be moving. When sensing rough, uneven and/or loose terrain, for example, a runner may adjust his or her motions.
Commonly-owned U.S. Pat. No. 6,990,755 describes an article of footwear having an articulated sole structure in which multiple sipes separate discrete sole elements of the midsole. The resulting sole structure helps to simulate a sensation of barefoot running while at the same time providing a degree of cushioning and protection to the wearer foot. However, there remains an ongoing need for improved footwear that protects the wearer foot but that also provides a natural motion feel and tactile feedback regarding ground conditions.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the invention.
In some embodiments, an article of footwear may include an upper, an outsole and a compressible foam midsole. The outsole may be bonded directly to an exterior face of a lasting element of the upper. The midsole may be contained within, and be non-destructively removable from, the upper.
In some embodiments, an article of footwear may include an upper and an outsole. The outsole may include multiple discrete lugs distributed across a bottom exterior surface of the outsole. A compressible foam midsole may be contained within the upper. That midsole may be non-destructively removable from the upper and may include a plurality of raised regions on a top surface configured to receive a plantar face of a foot of a wearer.
In some embodiments, an article of footwear may include an upper and an outsole bonded to the upper. The outsole may include multiple discrete lugs distributed across a bottom exterior surface of the outsole. Each of the lugs may be separated from adjacent lugs by a gap region. The outsole may have a thickness of between about 0.5 millimeters and about 0.8 millimeters in the gap regions. The article may further include a compressible foam midsole contained within the upper.
Additional embodiments are described herein.
Some embodiments are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements.
In at least some embodiments, an article of footwear comprises a thin and highly flexible outsole. The outsole may be directly bonded to an upper of the article. In certain embodiments, the outsole may be directly bonded to the underside of a lasting element of that upper. The outsole may further comprise multiple discrete lugs. The article may further include an internal foam midsole resting directly over the lasting element. In response to ground forces imposed by walking, running or other actions by the article wearer, individual lugs may displace vertically to provide localized pressure on the midsole. The midsole may then transfer a portion of that localized pressure to a localized region of the wearer's foot. As a result, the wearer may receive tactile feedback that provides information about the condition of the ground surface over which the wearer may be moving. An article of footwear according to at least some embodiments may provide a wearer with a highly defined feel for ground surface features, while still affording impact force attenuation and other protection. As further described herein, additional features of one or more embodiments may further enhance the degree to which a wearer is able to sense physical details of a ground surface.
The following discussion and accompanying figures describe articles of footwear in accordance with several embodiments. Shoes according to various embodiments have configurations that are suitable for athletic activities such as running and cross-training. Other embodiments include footwear adapted for basketball, golf, walking, hiking and other athletic and nonathletic activities. Persons skilled in the relevant art will thus recognize that concepts disclosed herein may be applied to a wide range of footwear styles and are not limited to the specific embodiments discussed below and depicted in the figures.
To assist and clarify subsequent description of various embodiments, various terms are defined herein. Unless context indicates otherwise, the following definitions apply throughout this specification (including the claims). “Shoe” and “article of footwear” are used interchangeably to refer to articles intended for wear on a human foot. A shoe may or may not enclose the entire foot of a wearer. For example, a shoe could include a sandal or other article that exposes large portions of a wearing foot. The “interior” of a shoe refers to space that is occupied by a wearer's foot when the shoe is worn. An interior side, surface, face or other aspect of a shoe component refers to a side, surface, face or other aspect of that component that is (or will be) oriented toward the shoe interior in a completed shoe. An exterior side, surface, face or other aspect of a component refers to a side, surface, face or other aspect of that component that is (or will be) oriented away from the shoe interior in the completed shoe. In some cases, the interior side, surface, face or other aspect of a component may have other elements between that interior side, surface, face or other aspect and the interior in the completed shoe. Similarly, an exterior side, surface, face or other aspect of a component may have other elements between that exterior side, surface, face or other aspect and the space external to the completed shoe.
Unless the context indicates otherwise, “top,” “bottom,” “over,” “under,” “above,” “below,” and similar locational terms assume that a shoe or shoe structure of interest is in the orientation that would result if the shoe (or shoe incorporating the shoe structure of interest) is in an undeformed condition with its outsole (and/or other ground-contacting sole structure element(s)) resting on a flat horizontal surface. Notably, however, the term “upper” is reserved for use in describing the component of a shoe that at least partially covers a wearer foot and helps to secure the wearer foot to a shoe sole structure.
Elements of a shoe can be described based on regions and/or anatomical structures of a human foot wearing that shoe, and by assuming that shoe is properly sized for the wearing foot. As an example, a forefoot region of a foot includes the metatarsal and phalangeal bones. A forefoot element of a shoe is an element having one or more portions located over, under, to the lateral and/or medial sides of, and/or in front of a wearer's forefoot (or portion thereof) when the shoe is worn. As another example, a midfoot region of a foot includes the cuboid, navicular, medial cuneiform, intermediate cuneiform and lateral cuneiform bones and the heads of the metatarsal bones. A midfoot element of a shoe is an element having one or more portions located over, under and/or to the lateral and/or medial sides of a wearer's midfoot (or portion thereof) when the shoe is worn. As a further example, a heel region of a foot includes the talus and calcaneus bones. A heel element of a shoe is an element having one or more portions located over, under, to the lateral and/or medial sides of, and/or behind a wearer's heel (or portion thereof) when the shoe is worn. The forefoot region may overlap with the midfoot region, as may the midfoot and heel regions.
Unless indicated otherwise, a longitudinal axis refers to a horizontal heel-toe axis along the center of a shoe and that is roughly parallel to a line that would follow along the second metatarsal and second phalanges of a wearer foot. A transverse axis refers to a horizontal axis across a shoe that is generally perpendicular to a longitudinal axis. A longitudinal direction is parallel (or roughly parallel) to a longitudinal axis. A transverse direction is parallel (or roughly parallel) to a transverse axis.
In the embodiment of shoe 100, upper 101 may comprise a lightweight mesh panel 102 and a partial sock 103. Partial sock 103 may be formed from a knit textile material that includes elastic fibers. Partial sock 103 includes an ankle collar 105 that completely surrounds a wearer foot at or above ankle level. An opening 106 in ankle collar 105 allows a wearer to insert a foot into the interior of shoe 100. The ankle collar 105 and/or partial sock 103 may provide a tight fit to the wearer foot. In some embodiments, the ankle collar 105 and/or partial sock 103 may include features (e.g., raised ribs, nubs, etc.) that apply localized pressure to the wearer foot, e.g., to enhance proprioception.
Mesh panel 102 covers the sides of the wearer foot and the top of the wearer foot in a forefoot region forward of a lacing gap 104. Lacing gap 104 is analogous to a tongue opening in certain conventional footwear designs. In the embodiment of shoe 100, however, a conventional tongue is not included. Instead, edges of partial sock 103 are joined to mesh panel 102 at or near edges of lacing gap 104. Other edges of partial sock 103 around a lower portion of ankle collar 105 are joined to top edges of mesh panel 102 in a heel region of upper 101. A lace 107 passes through multiple loops 108 and can be used to cinch upper 101 onto a wearer foot.
Although not visible in
Mesh panel 102 of upper 101 further includes a skin portion 114 bonded to the exterior face of the mesh. Skin portion 114 may be formed from thermoplastic polyurethane (TPU), from TPU having a polyurethane (PU) exterior face, or from other polymer materials. In some embodiments, mesh panel 102 may be formed using materials and techniques as described in commonly owned U.S. patent application Ser. No. 12/603,498, filed Oct. 21, 2009, and titled “Composite Shoe Upper and Method of Making Same,” which application is incorporated by reference herein in its entirety.
As previously indicated, and as further shown in
The sizes of lugs 112 may vary based on location. Moreover, the heights of lugs 112 may also vary based on location. As used herein, the “height” of a lug refers to the amount by which the lug extends beyond the exterior surface of outsole 110 that forms gaps 116 surrounding that lug. In some embodiments, lugs located in regions that are expected to experience greater foot pressure may have heights that are greater than the heights of lugs in other regions. The regions that are expected to experience greater pressure may vary based on the activity for which a particular shoe is intended. In at least some embodiments, such regions may include the heel region, the region of the metatarsal-phalangeal joints, and the big toe (i.e., the hallux).
In at least some embodiments, lugs 112 have a cross-sectional area size that is small relative to the area of the outsole 110 ground contact surface. For example, and as seen in
In some embodiments, and as can also been seen in
Outsole 110 may be formed from synthetic rubber having a hardness and other properties similar to those of synthetic rubber compounds conventionally used for footwear outsoles. As previously indicated, however, outsole 110 is highly flexible. Accordingly, outsole 110 in at least some embodiments has a thickness of between approximately 0.5 millimeters to approximately 0.8 millimeters in regions of gaps 116. This permits outsole 110 to flex significantly between adjacent lugs 112. In turn, this allows individual lugs 112 to transfer ground pressure to a wearer foot with a higher definition (e.g., by displacing with respect to adjacent lugs in the vertical direction). This permits a wearer of shoe 100 to better feel individual features of the ground or other surface on which the wearer is standing, walking, running, etc. In some embodiments, portions of outsole 110 may be formed from a rubber compound that is harder and more durable than other portions of the outsole. The higher durability rubber could be used, e.g., in a crash pad located within the heel region and/or on the bottoms of lugs located in certain other high pressure regions that typically wear more quickly.
So as to generally show the position of midsole 200 within shoe 100, upper 101 and outsole 110 are approximately indicated with broken lines in
Midsole 200 may also include a heel reinforcement 202. Heel reinforcement 202 may be formed from a foam that is denser and less compressible than other portions of midsole 200, and it may be formed as a separate component engaged with the foam material of the midsole 200. Heel reinforcement 202 helps provide stability to a wearer foot by centering the wearer heel. In some embodiments, the shape and/or location of a heel reinforcement may vary. A heel reinforcement configuration may vary based on an intended use of a shoe and/or based on gait characteristics of a wearer. For example, a midsole of a shoe intended for wear while playing basketball may have a heel reinforcement that is larger and/or more dense than a heel reinforcement of a midsole of a shoe intended for linear running. As another example, the heel reinforcement of an “over-pronator” may be sized and/or shaped differently from that of a wearer with a more neutral gait. In some embodiments, a heel reinforcement may be omitted. Midsole 200 further includes a plurality of transverse sipes 201, as discussed in more detail below in conjunction with
Midsole 200 is formed from a viscoelastic foam material. In at least some embodiments, midsole 200 is formed from a compressed ethylene vinyl acetate (EVA) foam. EVA foams are also known as phylon. In at least some such embodiments, and for portions of midsole 200 other than heel cup 202, the EVA foam may have properties in ranges such as are listed in Table 1.
Other materials could also be used for midsole 200. As but one example, in some embodiments a midsole may be formed from foam materials such as those used in the LUNAR family of footwear products available from NIKE, Inc. of Beaverton, Oreg. Additional examples of foam materials that can be used for midsole 200 include materials described in U.S. Pat. No. 7,941,938, which patent is hereby incorporated by reference herein. Other materials that can be used for midsole 200 include TPU and PU foams.
Top surface 205 and the interior sides of edge 206 may have a pattern formed thereon so as to increase friction relative to the socked foot of a shoe 100 wearer. The pattern may comprise raised portions 207 that are separated by shallow channels 208. In some embodiments, raised portions 207 have heights (relative to the surrounding channels 208) of approximately 1 millimeter. Raised portions 207 cooperate with lugs 112 and help to transmit sensations of ground features to the underside of a wearer's foot. Channels 208 may further help to increase air flow to the underside of a wearer foot and permit greater moisture evaporation than would occur if top surface 205 were smooth.
Although the raised portions 207 comprises triangles in the embodiment of midsole 200, other shapes could be employed. In at least some embodiments, outsole lugs 112 and raised portions 207 are sized so that they are of approximately the same scale. In some embodiments, for example, an average of the cross sectional areas of outsole lugs is within a range of about 50% to about 200% of an average of the cross sectional areas of the raised portions. In some embodiments, an average of the cross sectional areas of outsole lugs is within a range of about 20% to about 500% of an average of the cross sectional areas of the raised portions. In certain embodiments, the outsole lugs and the midsole raised portions are sized so that the number of lugs along a first path crossing the outsole in a transverse direction is within a range of about 50% to about 200% of the number of raised portions located on along a second transverse path that crosses the midsole and is directly above the first transverse path. In some embodiments, the number of lugs along a first path crossing the outsole in a transverse direction is within a range of about 20% to about 500% of the number of raised portions located on along a second transverse path directly above the first transverse path. In some embodiments, the pattern of raised portions on a midsole top surface may correspond to or otherwise correlate with a pattern of lugs on the outsole of a shoe containing that midsole.
Sipes in midsole 200 can be formed by cutting those sipes after midsole 200 has been molded. Such cutting can be performed using a hot knife tool, a laser or other cutting device. In some embodiments, sipes may be formed during molding of a midsole, e.g., by including blades in a midsole mold that correspond to desired sipe locations. In some embodiments, sipes are formed so that spanning portion 302 has a thickness t above the sipes of approximately 3 millimeters. In some embodiments, a portion of a midsole configured to lie under a wearer forefoot has a total thickness between about 3 millimeters and about 6 millimeters. In some such embodiments having thinner midsoles, sipes may be of reduced depth or absent.
In at least some embodiments, midsole 200 lacks a top cloth or other liner element applied to surface 205. In this way, the wearer foot (perhaps covered by a sock) rests directly on an exposed surface of the foam that forms midsole 200. The absence of a top cloth also helps increase the degree to which details about the ground surface are transmitted vertically through the sole structure and felt by the underside of a wearer foot. If a top cloth were adhered to surface 205, that top cloth would apply a tensile force tending to resist deformation of midsole 200 as a wearer moves. That tensile force would moderate the degree to which midsole 200 could transfer pressure to the wearer foot from individual lugs 112, thereby reducing the definition with which a user is able to sense features of the ground.
In some embodiments, a midsole may have additional elements added to a top surface such as surface 205. In at least some such embodiments, however, those additional elements only span a limited portion of the midsole top surface. For example, individual features such as triangles 207 might have a covering, but such covering may not span gaps (such as channels 208) between such features. Additionally or alternatively, if desired, a partial top cloth or liner element could be provided (even one spanning some gaps or channels 208) in areas of the foot where the transmission of pressure through the sole structure is less useful or desired.
The upward pressure P on lug 112-1 is transferred to the underside of midsole 200. Although the foam of midsole 200 compresses somewhat (thereby absorbing some of the energy from pressure P), the localized region LR of midsole 200 over lug 112-1 is also moved upward. The underside of the wearer foot senses this pressure in region LR. As a result, the shoe 100 wearer can realize that he or she has stepped on an object in this region. The combination of discrete lugs 112, highly flexible gaps 116 and midsole 200 allows the shoe 100 wearer to sense the presence of a ground object with more definition than would may be possible with many conventional footwear designs. These features also allow the wearer to sense and feel the contours or slope of the ground surface, even if not stepping on a foreign object.
Shoe 400 further includes an outsole 410 that is similar to outsole 110 of shoe 100. In particular, outsole 410 is thin, highly flexible and bonded directly to a lasting element (not shown) of upper 401. Outsole 410 further includes a plurality of discrete lugs 412. Unlike outsole 110, however, outsole 410 includes a more raised lateral edge 497 and a more raised medial edge 496. Edges 496 and 497 provide increased lateral and arch support, respectively.
Midsole 500 includes a forefoot lateral reinforcement 510 and a forefoot medial reinforcement 511. Reinforcements 510 and 511, which may be formed from higher density and less compressible foams similar to heel reinforcement 202 of midsole 200, help to stabilize a wearer forefoot. In the embodiment of shoe 500, midsole 400 lacks a heel reinforcement (although one could be provided, if desired). Reinforcements 510 and 511 (as well as 202) also may be separately formed components that are engaged with the foam of the midsole components (e.g., via cements or adhesives, mechanical connectors, etc.).
Shoe 600 includes an outsole 610. Like outsole 110 of shoe 100, outsole 610 is thin, highly flexible and bonded directly to a lasting element (not shown) of upper 601. Outsole 610 further includes a plurality of discrete lugs 612.
Midsole 700 includes a forefoot lateral reinforcement 710 and a heel reinforcement 702. Reinforcements 702 and 710, which may be formed from higher density and less compressible foams similar to heel reinforcement 202 of midsole 200, help to stabilize a wearer forefoot and heel.
In some embodiments, shoes having outsoles and/or midsoles such as those of shoes 100, 400 and 600, as well as shoes having outsoles and/or midsoles according to other embodiments, may have an upper such as is described in commonly-owned U.S. patent application Ser. No. 13/681,842 (filed Nov. 20, 2012, and titled “Footwear Upper Incorporating A Knitted Component With Collar And Throat Portions”), which application in its entirety is incorporated by reference herein.
In some embodiments, only some portions of an outsole may include discrete lugs separated by gaps, with the outsole thickness in those gaps being relatively thin. For example, some embodiments may include an outsole in which some or all of the forefoot region is similar to the forefoot region of outsole 110, of outsole 410 or of outsole 610, but in which the heel region is substantially thicker and/or lacks discrete lugs.
In some embodiments, a shoe may include an outsole that is slightly thicker and/or that may include an additional midsole element. For example, a rubber outsole may be bonded to a relatively thin external midsole formed from EVA or other compressible material, with that external midsole in turn bonded to a lasting element of an upper. The outsole and external midsole may still be relatively thin so as to, e.g., permit individual lugs on the outsole to exert upward pressure independently of adjacent lugs. In some such embodiments, a removable internal midsole similar to midsoles described above (e.g., midsole 200, 500 and/or 700) may also be included.
As previously indicated, upper 101 and uppers shown in other drawings, outsole 110 and outsoles shown in other drawings, and midsole 200 and midsoles shown in other drawings are merely exemplary. There are innumerable additional embodiments in which an upper, outsole and/or midsole may be functionally similar to an upper, outsole or midsole as described herein, but which may have a different visual appearance.
The foregoing description of embodiments has been presented for purposes of illustration and description. The foregoing description is not intended to be exhaustive or to limit embodiments of the present invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of various embodiments. The embodiments discussed herein were chosen and described in order to explain the principles and the nature of various embodiments and their practical application to enable one skilled in the art to utilize the present invention in various embodiments and with various modifications as are suited to the particular use contemplated. Any and all combinations, subcombinations and permutations of features from above-described embodiments are the within the scope of the invention. With regard to claims directed to an apparatus, an article of manufacture or some other physical component or combination of components, a reference in the claim to a potential or intended wearer or a user of a component does not require actual wearing or using of the component or the presence of the wearer or user as part of the claimed component or component combination.