Article of footwear with inner and outer midsole layers

An article of footwear includes an outsole that has a bottom portion and a medial arch portion extending upward from the bottom portion. The medial arch portion of the outsole has a base and a plurality of protrusions extending outward from the base. The plurality of protrusions are arranged in vertical alignments. In each one of the vertical alignments, at least one protrusion of the plurality of protrusions is closer to the bottom portion and has a larger effective diameter than at least one other protrusion of the plurality of protrusions that is further from the bottom portion.

TECHNICAL FIELD

The present disclosure relates to a sole assembly for an article of footwear.

BACKGROUND

Footwear typically includes a sole configured to be located under a wearer's foot to space the foot away from the ground or floor surface. Soles can be designed to provide a desired level of cushioning. Athletic footwear in particular sometimes utilizes polyurethane foam, rubber, or other resilient materials in the sole to provide cushioning.

DETAILED DESCRIPTION

An article of footwear is disclosed that includes a variety of features making it suitable for use in different activities, including athletic activities, such as but not limited to running, rope climbing, and weightlifting. An article of footwear comprises an outsole that has a bottom portion and a medial arch portion extending upward from the bottom portion. The medial arch portion of the outsole has a base and a plurality of protrusions extending outward from the base. The plurality of protrusions are arranged in vertical alignments. In each one of the vertical alignments, at least one protrusion of the plurality of protrusions is closer to the bottom portion and has a larger effective diameter than at least one other protrusion of the plurality of protrusions that is further from the bottom portion.

In one or more embodiments, in each one of the vertical alignments, at least one protrusion of the plurality of protrusions closer to the bottom portion has a greater length than at least one other protrusion of the plurality of protrusions that is further from the bottom portion, with length of a protrusion measured along a center axis of the protrusion from the base to a distal end of the protrusion.

In one or more embodiments, the plurality of protrusions decrease in length in a direction away from the bottom portion. In one or more embodiments, the plurality of protrusions are of the same shape.

In one or more embodiments, the medial arch portion is generally triangular.

In one or more embodiments, the medial arch portion has a rear edge, a front edge, and an apex between the rear edge and the front edge. The rear edge angles forward from the bottom portion to the apex, and the front edge angles rearward from the bottom portion to the apex.

In one or more embodiments, the bottom portion has tread elements in the forefoot region, the midfoot region, and the heel region. At least some of the tread elements of the bottom portion and at least some of the plurality of protrusions may be of an identical shape.

In one or more embodiments, the outsole further comprises a lateral arch portion extending upward from the bottom portion. The lateral arch portion may have a base and a plurality of protrusions extending outward from the base. At least one of the plurality of protrusions extending outward from the base of the medial arch portion has a greater length than at least one of the plurality of protrusions extending outward from the base of the lateral arch portion, with length of a protrusion measured along a center axis of the protrusion from the base to a distal end of the protrusion.

In one or more embodiments, the article of footwear further comprises an upper. The medial arch portion and the lateral arch portion are secured to a medial side and to a lateral side of the upper, respectively. A forefoot region of the outsole has sidewall portions extending upward from the bottom portion and secured to the medial side and to the lateral side of the upper.

In an aspect of the present teachings, an article of footwear comprises an outsole that has a bottom portion with a peripheral edge, and has a medial arch portion. The bottom portion establishes a ground contact surface extending to the peripheral edge. The medial arch portion has a base extending upward from the peripheral edge of the bottom portion and a plurality of protrusions extending outward from the base.

In one or more embodiments, the plurality of protrusions are arranged in vertical alignments. In each one of the vertical alignments, at least one protrusion of the plurality of protrusions is closer to the bottom portion and has a larger effective diameter than at least one other protrusion of the plurality of protrusions that is further from the bottom portion.

In one or more embodiments, each of the plurality of protrusions is of the same shape.

In one or more embodiments, the bottom portion has a forefoot region, a midfoot region, and a heel region, and has tread elements in the forefoot region, the midfoot region, and the heel region. The peripheral edge may be free of the tread elements and of the plurality of protrusions. At least some of the tread elements of the bottom portion may be of an identical shape as at least some of the plurality of protrusions.

In one or more embodiments, the medial arch portion has a rear edge, a front edge, and an apex between the rear edge and the front edge. The rear edge angles forward from the bottom portion to the apex, and the front edge angles rearward from the bottom portion to the apex.

In one or more embodiments, the article of footwear further comprises an upper. The medial arch portion is secured to a medial side of the upper. A forefoot region of the outsole has a sidewall portion extending upward from the bottom portion and secured to the medial side of the upper.

Those having ordinary skill in the art will recognize that terms such as “above,” “below,” “upward,” “downward,” “top,” “bottom,” etc., are used descriptively relative to the figures, and do not represent limitations on the scope of the invention, as defined by the claims.

The above features and advantages and other features and advantages of the present disclosure are readily apparent from the following detailed description of modes for carrying out the concepts of the disclosure when taken in connection with the accompanying drawings.

Referring to the drawings, wherein like reference numbers refer to like components throughout the several views,FIG. 1is a medial side view of an article of footwear10that includes a sole assembly12with an outsole14, an outer midsole layer16, and an inner midsole layer18(shown inFIG. 3). As further disclosed herein, the inner midsole layer18is not adhered or otherwise secured to any component of the article of footwear10, thereby preventing undesirable rigidity. The inner midsole layer18is not as hard as the outer midsole layer16to enhance cushioning for running or other activities, while at the same time the outer midsole layer16and the outsole14provide stability for activities such as weightlifting. Moreover, the outsole14includes medial and lateral arch portions20,22shown inFIGS. 1 and 2that extend upward along and are secured to a medial side24of a footwear upper26and to a lateral side28of the upper26at a perimeter30of the upper26to provide traction for activities such as rope climbing.

As used herein, a lateral side of a component for an article of footwear, such as a lateral side28of the upper26, is a side that corresponds with the side of the foot of the wearer of the article of footwear10that is generally further from the other foot of the wearer (i.e., the side closer to the fifth toe of the wearer). The fifth toe is commonly referred to as the little toe. A medial side of a component for an article of footwear, such as a medial side24of the article of footwear10, is the side that corresponds with an inside area of the foot of the wearer and is generally closer to the other foot of the wearer (i.e., the side closer to the hallux of the foot of the wearer). The hallux is commonly referred to as the big toe. The lateral side28and the medial side24both extend from the foremost extent32of the upper26to the rearmost extent34of the upper26.

As best shown inFIGS. 1, 9, and 12, the outsole14has a heel region36, a midfoot region38, and a forefoot region40. The midfoot region38is between the heel region36and the forefoot region40. For purposes of discussion, the heel region36, the midfoot region38, and the forefoot region40are respectively defined as the rearmost third, the middle third, and the foremost third of the outsole14. Accordingly, the forefoot region40extends from a foremost extent A of the outsole14to lateral marker B, which is spaced one-third of the way from the foremost extent A to the rearmost extent D of the outsole14along a longitudinal axis L. The midfoot region38extends from lateral marker B to lateral marker C, which is spaced two-thirds of the way from the foremost extent A to the rearmost extent D along the longitudinal axis L. The heel region extends from the lateral marker C to the rearmost extent D.

The heel region36generally includes portions of the outsole14corresponding with rear portions of a human foot including the calcaneus bone and of a size corresponding with the outsole14and article of footwear10. Forefoot region40generally includes portions of the outsole14corresponding with the toes and the joints connecting the metatarsals with the phalanges of the human foot of the size corresponding with the outsole14and article of footwear10. Midfoot region38generally includes portions of the outsole14corresponding with an arch area of the human foot of the size corresponding with the outsole14and article of footwear10.

FIG. 9shows that the outer midsole layer16is secured to the outsole14and extends only over the heel region36and a portion of the midfoot region38. The inner midsole layer18is supported by the outer midsole layer16and the outsole14but is not fixed thereto. In other words, the inner midsole layer18is not adhered, sewn, bonded, welded, or otherwise secured to any other component of the article of footwear10. Instead, the inner midsole layer18simply rests on a strobel unit42within a cavity41defined and bounded by the upper26and the strobel unit42. The strobel unit42is stitched to the upper26. Alternatively, heat seaming, bonding, or other methods of securing the footwear upper26to the strobel unit42can be used. The strobel unit42is also adhered or bonded directly to an upward-facing surface46of the outer midsole layer16at the heel region36, to a portion of the midfoot region38not covered by the outer midsole layer16, and directly to an upward-facing surface48of the outsole14at the forefoot region40. The upper26can be comprised of multiple separate pieces and materials such as fabric, textiles, leather, plastics, etc. With reference toFIG. 1, in the embodiment shown, the upper26includes a relatively stiff polymer heel counter27, a leather portion29, a fabric mesh portion31, a polymer toe cap33, a cloth lining35, and a nylon pull strap37.

As shown inFIGS. 3 and 9, the inner midsole layer18is a full-length midsole layer, such that it extends over the heel region36, the midfoot region38, and the forefoot region40when placed in the cavity41. The inner midsole-layer18can thus be selectively inserted or removed from the cavity41, and is referred to as a drop-in midsole. Because the inner midsole layer18is not secured to any component of the article of footwear10, it may exhibit some minimal relative movement with respect to the strobel unit42, the outer midsole layer16and the outsole14under some load forces. This reduces rigidity, and produces a flexible feel during wear. However, the inner midsole layer18is supported by outer midsole layer16and the outsole14, and is relatively confined by the outer midsole layer16and the upper26. For example, as best shown inFIGS. 4 and 8, the outer midsole layer16is configured to surround a periphery50of the inner midsole layer18at the heel region36.

As further discussed herein, the outer midsole layer16is harder than the inner midsole layer18. For example, in one embodiment, the outer midsole layer16is seven points harder than the inner midsole layer18when hardness is measured on a Durometer Shore A scale. Both the inner midsole layer18and the outer midsole layer16can be a polymeric foam, such as ethylene vinyl acetate (EVA) foam. The inner midsole layer18can be a lighter weight, less dense foam than the outer midsole layer16. The inner midsole layer18is configured with a substantially uniform hardness that provides appropriate cushioning and compliance under the heel of a wearer, while the surrounding outer midsole layer16is harder to provide lateral support, resiliency, and energy absorption at the heel region36. As shown inFIG. 3, the inner midsole layer18has a fabric liner39secured to a foot-receiving surface44, i.e., an upper surface.

The outsole14, on the other hand, is not of a uniform hardness. Specifically,FIG. 12shows a boundary H that generally separates first portion52of the outsole from a second portion54of the outsole14. The first portion52extends over only some of the forefoot region40and coincides generally with a pressure-bearing region under the ball of a wearer's foot. The second portion54includes an entire remainder of the outsole14. The first portion52has a first hardness, and the second portion54has a second hardness greater than the first hardness. The first portion52is softer than the second portion54, and has a greater coefficient of friction with respect to a ground surface GS, shown inFIG. 9, than does the harder rubber of the second portion54. The first portion52is thus both more compliant and provides greater traction with respect to forces conveyed from the ball of a wearer's foot through the forefoot region40, such as during lateral movement and/or climbing. The outsole14may be a thermoplastic rubber or other durable material. The material for the outsole14may be selected to provide a desirable combination of durability and flexibility.

With reference toFIGS. 9-12, the outsole14has a bottom portion60that defines a ground contact surface GCS. The ground contact surface GCS includes those portions of the bottom portion60that are configured to be in contact with the ground surface GS ofFIG. 9when the article of footwear10is worn for most activities in which the wearer is generally upright, such as running or weightlifting. As is evident inFIGS. 9 and 12, the bottom portion60has a plurality of molded tread elements62of various sizes, most or all of which have a hexagonal shape. Other shapes of tread elements may be used within the scope of the present disclosure. The tread elements62extend outward from a base64of the outsole14. Accordingly, those ones of the tread elements62in contact with the ground surface GS establish the ground contact surface GS. As is shown inFIGS. 10, 11, 13, and 14, the tread elements62are configured so that the ground contact surface GCS of the outsole14is generally flat from a medial side66of the outsole14to a lateral side68of the outsole14when the article of footwear10is placed upright as shown and is not being worn, i.e., when the outsole14is unloaded, or when the outsole14is bearing the weight of a person wearing the article of footwear10and standing upright. As indicated inFIGS. 9, 13 and 14, not all of the tread elements62are likely to be in contact with the ground contact surface GCS at once, and different portions of the outsole14will be in contact with the ground as the wearer's foot moves relative to the ground.

The substantial flatness of the ground contact surface GCS from the medial side66to the lateral side68at any given location along the longitudinal axis L of the outsole14contributes to the stability of the article of footwear10. Specifically, the article of footwear10is relatively difficult to roll laterally given the substantial width and flatness of the bottom portion60. Additionally, as shown inFIG. 5, the outsole14has a medial sidewall portion70with a first side surface72that extends substantially perpendicularly to the bottom ground contact surface GCS. The outsole14also has a lateral sidewall portion74with a second side surface76that extends substantially perpendicularly to the bottom contact surface GCS. The medial sidewall portion70and the lateral sidewall portion74are adjacent the forefoot region40of the outsole14. A peripheral edge E1is defined by and is a corner61between the bottom portion60and the medial side wall portion70at an angled surface73, similar to a chamfer. A peripheral edge E2is defined by and between the bottom portion60and the lateral sidewall portion74at an angled surface77, similar to a chamfer, as also shown inFIG. 12. The peripheral edge E1extends between and is further defined by the medial arch portion20and the bottom portion60as indicated inFIGS. 1 and 6. The peripheral edge E1is the corner61of the outsole14between the bottom portion60and the medial arch portion20. The medial arch portion20has a rear edge RE, a front edge FE, and an apex A1between the rear edge RE and the front edge FE. The rear edge RE angles forward from a rearmost extent82A of the rear edge RE to the apex A1. The front edge FE angles rearward from a foremost extent82B of the front edge FE to the apex A1. The corner61extends between the bottom portion60and the medial arch portion20from the rearmost extent82A of the rear edge RE to the foremost extent82B of the front edge FE, as best shown inFIG. 1. By providing angled surfaces73,77with edges E1, E2rather than a more rounded transition from the bottom portion60to the sidewall portions70,74, the stability and resistance to lateral roll of the outsole14is increased.

FIGS. 1, 2, 6-7, 10-12show the medial arch portion20extending from the bottom portion60on the medial side24of the bottom portion60, and the lateral arch portion22extending from the bottom portion60on a lateral side28of the bottom portion60. The medial arch portion20and lateral arch portion22are generally triangular in shape, and extend approximately half-way up the sides of the upper26to an apex A1, A2, respectively.

A plurality of spaced protrusions80extend outward from a base82of the outsole14at the medial arch portion20and at the lateral arch portion22, as shown inFIGS. 1 and 2. Like the tread elements62, the protrusions80are hexagonal in shape, but other shapes may be used. In fact, the protrusions80serve as tread elements for the medial arch portion20and the lateral arch portion22, such as when the article of footwear10is used for rope climbing. During rope climbing, the medial arch portion20is generally pressed against a rope and used for traction during ascent. During descent, the climber may reposition his foot so that the lateral arch portion22is in contact with the rope. Generally, greater traction is desired when ascending, than when descending. During descent, a skilled rope climber may desire contact between the rope and the lateral arch portion22, but may wish to use the lateral arch portion22for sliding support against the rope to increase the speed of descent. Accordingly, a greater coefficient of friction is desired at the medial arch portion20than at the lateral arch portion22. To accommodate these needs, the spaced protrusions80extend further outward from the base82on the medial arch portion20than on the lateral arch portion22.FIG. 21shows the lateral and medial arch portions ofFIG. 7in larger view.FIGS. 7 and 20show that the longest spaced protrusions80on the medial arch portion20extend a distance D1from the base82, whileFIG. 20shows that the longest spaced protrusions80on the lateral arch portion22extend a lesser distance D2from the base82. The distances D1, D2outward from the base82are measured along a respective center axis C1, C2of the protrusion80.

It is also apparent inFIGS. 1, 2, and 7that the spaced protrusions80on either of the medial arch portion20or the lateral arch portion22extend further outward near the bottom portion60, and decrease in outward extension in a direction further away from the bottom portion60(i.e., protrusions80closer to the apex A1or A2extend outward less than those protrusions80closer to the bottom portion60). In addition to decreasing in length of extension, the spaced protrusions80also decrease in effective diameter in a direction away from the bottom portion60. In other words, protrusions80closer to the apex A1or A2have a smaller effective diameter than those protrusions80closer to the bottom portion60.FIGS. 1 and 2show a protrusion close to the bottom portion60having an effective diameter88A, while a protrusion closer to the apex A1or A2has a smaller effective diameter88B. As used herein, the effective diameter of the hexagonal protrusion80is the diameter of a circular protrusion having an equivalent surface area as the hexagonal face of the protrusion.

With reference toFIG. 15, the inner midsole layer18is formed with grooves90,92in a forefoot portion93of the inner midsole layer18. The grooves90,92extend over the forefoot region40of the outsole14when the inner midsole layer18is placed in the cavity41of the article of footwear10. The grooves90,92are in a bottom surface94of the inner midsole layer18that contacts the strobel unit42in the forefoot region40. The grooves90are transverse grooves as they extend transversely from a medial side95to a lateral side96of the inner midsole layer18. Groove92is a longitudinal groove as it extends longitudinally and intersects at least some of the transverse grooves92. The grooves90,92increase compliance and flexibility of the inner midsole layer18in the forefoot region40.

FIG. 15also shows that the bottom surface94of the inner midsole layer18that contacts the strobel unit42has spaced recesses98, only some of which are labeled with reference numbers. The spaced recesses98are in the bottom surface94of the inner midsole layer18that contacts the strobel unit42in the forefoot region40, and therefore extend over the forefoot region40of the outsole14when the inner midsole layer18is placed in the cavity41. The spaced recesses98increase compliance of the material of the inner midsole layer18in the forefoot region40. Additionally, the spaced recesses98increase the coefficient of friction of the inner midsole layer18on the strobel unit42relative to a relatively smooth midfoot portion99of the inner midsole layer18. The increased coefficient of friction in the forefoot region93helps to limit sliding movement of the inner midsole layer18relative to the strobel unit42. The pattern of the spaced recesses98inFIG. 15generally coincides with the first portion52of the outsole14(shown inFIG. 12) that has softer rubber than the second portion54. The grooves90,92, spaced recesses98, and first portion52thus all align in the forefoot region40to increase compliance, flexibility, and cushioning in the forefoot region40of the article of footwear10.

FIG. 15shows that the inner midsole layer18also has transverse grooves100in a heel portion102of the inner midsole layer18. The grooves100are generally shallower than the grooves90. The grooves100help to increase the compliance and coefficient of friction of the inner midsole layer18in the heel region102relative to a relatively smooth midfoot portion99of the inner midsole layer18. The increased coefficient of friction in the heel region102helps to limit sliding movement of the inner midsole layer18relative to the strobel unit42when the inner midsole layer18is placed in the cavity41.

FIGS. 16-19show that the inner midsole layer18has lateral and medial sidewall portions106A,106B both of which have longitudinally extending pleats108generally in the forefoot portion93and extending partway into the midfoot portion99as indicated inFIG. 17. The pleats108may also be referred to alternating ridges and valleys. The pleats108increase compliance of the forefoot portion93of the inner midsole layer18. It is apparent inFIGS. 16 and 17that the grooves100of the heel portion102continue from the bottom surface94of the inner midsole layer18to the sidewall portions106A,106B.

While several modes for carrying out the many aspects of the present teachings have been described in detail, those familiar with the art to which these teachings relate will recognize various alternative aspects for practicing the present teachings that are within the scope of the appended claims.