CN110464077B

CN110464077B - Footwear with improved traction

Info

Publication number: CN110464077B
Application number: CN201811189666.0A
Authority: CN
Inventors: W.J.卡斯; C.A.马蒂斯; D.W.费拉
Original assignee: Wolverine Outdoors Inc
Current assignee: Gemini Asia Maile Co ltd
Priority date: 2018-05-11
Filing date: 2018-10-12
Publication date: 2021-05-04
Anticipated expiration: 2038-10-12
Also published as: CN110464077A

Abstract

An article of footwear includes an outsole having first and second treads comprised of a first material and defining first and second ground contacting surfaces. The second tread includes a layer of a second material underlying the first material, the second material being less resistant to wear than the first material. The second ground contacting surface of the second tread extends below the first ground contacting surface of the first tread. The second tread is configured to move upward when the second ground contacting surface engages a ground surface to distribute ground forces across both the first tread and the second tread. The second material of the second tread has less wear from the ground surface than the second material would have if the second tread remained at the second distance when a ground force was applied.

Description

Footwear with improved traction

Background

The present invention relates to footwear, and more particularly to footwear having improved traction (or grip) for use on icy or slippery surfaces.

The outsole of the shoe is designed to provide certain functions. It provides a stable platform and underfoot protection for the wearer's foot. The outsole also provides traction between the shoe and the underfoot surface to enable the wearer to propel, brake, and change direction over the surface. The outsole is generally durable and wear resistant, thereby providing the user with a reasonable outsole life. Many athletic shoe outsoles are made of rubber, which is resilient and has a relatively high coefficient of friction on dry surfaces. Other outsoles are made of polyurethane plastic, which is somewhat harder, but provides enhanced wear resistance. However, this type of outsole may lack traction on certain types of surfaces.

Various outdoor activities involve passage over icy terrain or frozen bodies of water, which can present difficulties when footwear does not have sufficient traction. The technical performance of footwear for such activities depends largely on the outsole of the footwear. Accordingly, hiking and athletic shoes that are often worn during such outdoor activities are designed for wearing on slippery surfaces (e.g., wet ground, snow, or ice), and typically have soles made of hard, heavy, waterproof materials (e.g., rubber or plastic). Outsoles for such shoes and boots typically include ground engaging elements, such as treads (treads) and/or studs, that provide certain ground engaging characteristics that improve traction on the sliding surface. However, some of these features may result in the sole becoming more rigid and less flexible. Other footwear soles may include sipes (siping), which may improve traction on flat wet surfaces (e.g., ship decks or docks), but generally do not significantly enhance traction on uneven surfaces (e.g., rocks, uneven surfaces, or ice).

Accordingly, there remains room in the footwear art for improvement to provide high traction for traversing wet, slippery and/or icy terrain or other surfaces while providing good wear resistance.

Disclosure of Invention

The footwear includes an upper and an outsole having first and second treads comprised of a first material and defining first and second ground contacting surfaces. The second tread includes a layer of a second material underlying the first material, the second material having a lower wear resistance than the first material and providing more traction on the slippery surface than the first material. The second ground contacting surface of the second tread extends below the first ground contacting surface of the first tread. The second tread is configured to move upward when the second ground contacting surface engages the ground surface to distribute ground forces across both the first tread and the second tread. The second material of the second tread wears less from the ground surface than if the second tread did not move upward but remained at the second distance when the ground force was applied.

In another embodiment, an article of footwear includes an upper, a midsole, and an outsole. The outsole includes first and second treads comprised of a first material having a first coefficient of static friction. The first tread defines a first ground-contacting surface. The second tread includes a layer of the second material underlying the first material. The second material has a second coefficient of static friction and defines a second ground contacting surface. The second coefficient of static friction is greater than the first coefficient of static friction, and the second ground contacting surface is disposed about 0.1 mm to 5.0 mm below the first ground contacting surface. The second tread compresses the midsole at least in an area above the second tread due to a weight of a wearer of the article of footwear until the second ground contacting surface moves upward to a position where the second ground contacting surface is substantially 0 mm below the first ground contacting surface.

In another embodiment, an article of footwear includes a tread arrangement including a first tread interspersed among a second tread. A plurality of channels are recessed into a lower surface of the outsole, and one of the channels surrounds an upper end of each second tread. The first tread is composed of a first material and defines a first ground-contacting surface. The second tread is composed of a first material and includes a layer of a second material underlying the first material; the second material defines a textured traction surface and a second ground contacting surface. The second ground contacting surface is disposed 0.1 mm to 5.0 mm below the first ground contacting surface. Due to the weight of the wearer of the footwear, when the outsole engages the ground surface, the second tread moves upward into the midsole a distance of about 0.1 mm to 5.0 mm, compressing the midsole at least in the area above the second tread. The second tread moves upward until the second ground contacting surface is substantially flush with the first ground contacting surface, thereby distributing ground forces across both the first tread and the second tread.

According to yet another embodiment, each channel surrounding each second tread provides localized flexibility to the outsole such that each second tread is movable upward when the second ground contacting surface engages the ground surface.

In yet another embodiment, the outsole includes a rib extending from the outsole and surrounding each second tread.

These and other objects, advantages and features of the invention will be more fully understood and appreciated by reference to the description of the current embodiment and the drawings.

Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of embodiments in various other embodiments and of being practiced or of being carried out in various alternative ways not explicitly disclosed herein. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including" and "comprising" and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof. Furthermore, enumeration may be used in the description of various embodiments. The use of enumeration should not be construed as limiting the invention to any particular order or number of components unless explicitly stated otherwise. The use of enumeration neither should be interpreted as excluding from the scope of the invention any additional steps or components that may be combined with or into the enumerated steps or components.

Drawings

FIG. 1 is a bottom view of an article of footwear including a sole assembly in accordance with a present embodiment;

FIG. 2 is a cross-sectional view of the sole assembly taken along line II-II of FIG. 1;

FIG. 3 is a cross-sectional view of the sole assembly taken along line III-III of FIG. 1, illustrating a second tread of the sole assembly disposed in an unloaded position;

FIG. 4 is a cross-sectional view of the sole assembly taken along line IV-IV of FIG. 1;

FIG. 5 is a cross-sectional view of the sole assembly taken along line V-V of FIG. 1;

FIG. 6 is a plan view of a second tread of the sole assembly;

FIG. 7 is a cross-sectional view of the second tread taken along line VI-VI of FIG. 6;

FIG. 8 is a cross-sectional view of the sole assembly taken along line III-III of FIG. 1, illustrating a second tread of the sole assembly disposed in a loaded position;

FIG. 9 is a cross-sectional view of an alternative embodiment of the article of footwear, taken along a line in a position similar to line III-III of FIG. 1;

FIG. 10 is a cross-sectional view of the alternative embodiment, taken along a line in a position similar to line IV-IV of FIG. 1;

FIG. 11 is a cross-sectional view of the alternative embodiment, taken along a line in a position similar to line V-V of FIG. 1; and

FIG. 12 is a cross-sectional view of the second tread of the alternative embodiment, taken along a line in a position similar to line VI-VI of FIG. 6.

Detailed Description

The present embodiments relate to improved articles of footwear. In these embodiments, the improved article of footwear includes a sole construction configured to provide improved traction for traversing wet, slippery, and/or icy terrain while providing improved wear resistance for wearing on hard surfaces or indoors.

Although the present embodiments are shown in the context of outdoor footwear, they may be incorporated into any type or style of footwear, including performance shoes (performance shoes), hiking shoes, cross-country shoes and boots, hiking boots, work boots, all terrain shoes, barefoot running shoes, athletic shoes, conventional tennis shoes, walking shoes, multi-activity shoes, casual shoes, dress shoes, or any other type of footwear or footwear component. In general, the shoe is well suited for climbing mountains, walking in winter, and traversing icy terrain features or other icy or slippery surfaces. For example, the shoe may be used to walk through icy, snowy, and/or slippery surfaces, such as those in a snowy mountain, or on a frozen pond, lake, ocean, or other body of water. As used herein, icy terrain features may include, but are not limited to, slippery, wet or icy outdoor hiking trails, slippery slopes, and frosted rock terrain or other hard surface features that are generally rough, jagged, and uneven. The shoe is also well suited to provide such characteristics for persons working outdoors in winter weather, where the ground surface may be icy, wet or otherwise slippery.

It should also be noted that directional terms, such as "vertical," "horizontal," "top," "bottom," "upper," "lower," "inner," "inward," "outer," and "outward" are used to help describe the invention based on the orientation of the embodiments shown in the drawings. Furthermore, the terms "medial," "lateral," and "longitudinal" are used in a manner commonly used in connection with footwear. For example, when used to refer to the sides of a shoe, the term "medial" refers to the medial side (i.e., the side facing the other shoe), and "lateral" refers to the lateral side. When used to refer to directions, the term "longitudinal direction" refers to a direction extending generally along the length of the footwear between the toe and heel portions, and the term "lateral direction" refers to a direction extending generally across the width of the footwear between the medial and lateral sides of the footwear. The use of directional terms should not be construed to limit the invention to any particular orientation.

An article of footwear in accordance with the present embodiment is shown in fig. 1-8 and is generally indicated at 10. Footwear 10 may include a textile upper (not shown) and a sole assembly 14. The upper may be formed from various material elements that are joined together to cover at least a portion of a foot of a wearer. The material elements may be selected based on the intended use of the article of footwear 10, and may include, for example, synthetic textiles, mesh textiles, polymers, or leather. The upper is generally configured so as not to interfere with the flexibility of sole assembly 14, and may include stretchable or elastic material elements. For example, the material element may comprise lycra, neoprene or spandex. The upper may include one or more closure elements, including, for example, laces or hook and loop fasteners. The upper additionally includes an upper opening for receiving a foot of a wearer and a lower perimeter for attachment to sole assembly 14.

As shown in fig. 2, sole assembly 14 may include a footbed 16, a midsole 18, and an outsole 20, but may include more or fewer elements of sole assembly 14 in other embodiments. For example, some embodiments may exclude a footbed, while other embodiments may include only a footbed and an outsole. Sole component 14 may include EVA foam with a cushioned top portion and a more robust, wear-resistant bottom portion. The components of sole assembly 14 may individually and/or collectively provide numerous attributes to an article of footwear 10, such as support, rigidity, flexibility, stability, cushioning, comfort, reduced weight, and/or other attributes. In addition, the footbed 16, midsole 18, and outsole 20 may define a forefoot region 34, a midfoot 36 or arch region, and a heel region 38.

The footbed 16 is positioned within the void defined by the upper, is generally non-stretchable and lightweight, and is bonded to the upper to provide a void for receiving a foot of a wearer. The footbed 16 may be constructed from a sheet of material, such as foam, EVA, PU, latex, gel, or other material, and provides cushioning due to its compressibility, and may also conform to the foot to provide comfort, support, and stability. The thickness of the footbed 16 may also vary from region to region. In addition, the footbed may be covered with a woven or nonwoven fabric, leather, or other material, and may be treated with an antimicrobial agent or other compound to reduce the odor and/or deterioration of the footbed. The lower perimeter limit (allowance) or edge of the upper may be stitched, glued, or otherwise secured to the footbed 16 around the perimeter of the footbed. Sole assembly 14 may be combined with any other type or style of upper construction, such as a Strobel construction, that is capable of being suitably joined with outsole 20. The joining of the sole assembly/outsole and the upper may be accomplished using adhesives, cements, injection molding, cast molding, or any other technique for joining the upper and the sole.

Referring specifically to fig. 3-5, midsole 18 is positioned below footbed 16 and includes a lower surface 30 and an upper surface 32. The midsole 18 may be constructed of a material having a density generally less than the density of the outsole 20; such as Ethylene Vinyl Acetate (EVA), Polyurethane (PU), latex, foam, gel, or other materials. In general, the density of the midsole is such that it compresses relatively easily to provide cushioning to the wearer's foot (e.g., heel). The midsole material may have the following hardness: alternatively from about 30 Asker C to about 65 Asker C, further alternatively from about 42 Asker C to about 48 Asker C, and even further alternatively from about 45 Asker C or about 43 Asker C. As used herein, "hardness" refers to any standard or other suitable hardness measurement (e.g., Asker C or Shore a durometer hardness values) that provides an indication of the hardness and/or flexibility of a material. Overall, a lower durometer value indicates a softer/more flexible material, and a higher durometer value indicates a harder/less flexible material. Overall, a stiffer material has a higher wear resistance, but is also less flexible. Conversely, softer materials have lower wear resistance, but are more flexible.

The outsole 20 is generally bonded to the upper and is disposed below a lower surface 30 of the midsole 18. The outsole 20 includes an upper surface 24 and a lower surface 26, and defines a base 22 on the lower surface 26 of the outsole 20. The base 22 is a generally continuous lower surface of the outsole 20 and substantially surrounds, but does not include, the tread. Alternatively, the base 22 may be defined by a lower surface of the outsole 20 or the midsole 18. Outsole 20 may include a plurality of treads extending downwardly from base 22, as described further below. The tread may be arranged as desired and need not be a repeating pattern. The tread may include one or more geometric shapes. The outsole 20 may be constructed of one or more materials, such as natural or synthetic rubber, thermoplastic polyurethane elastomer (TPU), nylon, polymer blends, wear-resistant polymers, elastomers, and/or other materials. Other materials (e.g., fiber reinforced polymers) may be used, which may include epoxy, polyethylene, or thermoset reinforced with carbon, glass, and/or aramid fibers for enhanced protection. The outsole material may have the following hardness: alternatively from about 40 Shore A to about 70 Shore A, and further alternatively from about 68 Shore A to about 72 Shore A.

The outsole 20 includes a plurality of treads and may include a plurality of first treads 40 and a plurality of second treads 50, as seen in fig. 1. The first tread 40 may be interspersed among the second tread 50. The treads 40, 50 may be integrally formed with the base 22. The base 22 can have a preselected thickness, such as from 1 mm to about 4 mm, and further optionally about 1.5 mm. The thickness may be selected to provide a desired flexibility between various treads, regions, and/or portions of outsole 20. The first tread 40 may be constructed of a first material having a first hardness and a first coefficient of static friction. Further, a lower surface of the first tread 40 defines a first ground contacting surface 42. The first ground contacting surface 42 is spaced below the base 22 a first distance D1.

The second tread 50 may be constructed of the first material and further includes a first layer 52 disposed below the first material. First layer 52 defines a second ground contacting surface 54. Second ground contacting surface 54 is spaced below base 22 a second distance D2. The second distance D2 is greater than the first distance D1. The second distance D2 of the second ground contacting surface 54 may be approximately 0.1 mm to 5.0 mm greater than the first distance D1 of the first ground contacting surface 42. Alternatively, the second distance D2 may be about 0.25 mm to 2.5 mm greater than the first distance D1, and further alternatively, the second distance D2 may be about 0.5 mm to 1.5 mm greater than the first distance D1. Accordingly, the second ground contacting surface 54 of the second tread 50 extends below the first ground contacting surface 42 of the first tread 40. When the

outsole tread

40, 50 is not loaded by the weight of the wearer, the ratio of the first distance D1 relative to the second distance D2 may optionally be at least 1: 1.1, further optionally in the range of 1: 1.4 and 1: 1.8, and even further optionally about 1: 1.8.

the second tread 50 may also include a shoulder or flange 56 at the upper end of the tread 50. The flange 56 may follow the shape of the tread 50, the shape of the tread 50 generally surrounding the uppermost portion of the tread wall 50W. In practice, tread wall 50W may transition to a flange 56 that projects outwardly from tread 50 at the upper end of tread 50. At the lower end of the tread 50, the tread wall 50W may transition to the interface surface 50I. There, the second material physically and/or chemically bonds and/or attaches to the first material and body 50B of the tread 50 and the first layer 52. Flange 56 may extend a distance beyond body 50B and wall 50W of tread 50. The flange 56 may be received in a similarly shaped recess 58 defined by the midsole 18. In some cases, the flange 56 may anchor the tread 50 to the midsole 18. Although not shown, the flange 56 may be overlapped on its lower surface 56L by the material constituting the midsole 18 for securing the tread thereto. As described in greater detail below, flanges 56 may assist in the compression of midsole 18 when footwear 10 is loaded due to the weight of the wearer and the contact of sole assembly 14 with the ground surface.

The first layer 52 defines a textured traction lower surface and is composed of a second material having a second hardness, a second coefficient of static friction, and less wear resistance than the first material. The first layer 52 can have a hardness greater than the hardness of the first material, alternatively from about 70 Shore A to about 90 Shore A. The second material may include a rubber, elastomer, and/or polymer compound with an optional filler component dispersed throughout the compound. The filler component or material may include reinforcing glass fibers, carbon or composite fibers, metal fibers, polymer fibers, particulate matter, and/or combinations thereof to render the second ground contacting surface 54 sandy and/or rougher, which enhances traction, particularly on wet ice and/or slippery or ice covered surfaces. Alternatively, the second material may provide up to three times better traction for the outsole 18 than a conventional outsole on a wet, icy surface.

Referring now to fig. 6 and 7, the outsole 20 also includes a plurality of channels 60 that are recessed upwardly into the lower surface 26 of the outsole 20. The channels 60 are configured to provide localized bending in the surrounding area so that the tread 50 may move upward. The channel 60 surrounds or encircles the flange 56 of each second tread 50. Each channel 60 may include opposing side walls 62 and a connecting top wall 64 that together define a width W and a depth D. The cross-section of the channel 60 (and in particular the side walls 62 and top wall 64) may be linear, curved, angled, segmented, circular, or polygonal. The depth D may extend partially through the thickness of the outsole 20. The width W and depth D of channels 60 may be selected to provide a desired amount of localized flexibility in corresponding regions of outsole 20. For example, the depth D of the channel 60 may be substantially equal to the thickness of the base 22 of the outsole 20. Alternatively, the depth D of the channel 60 may be two or three times the thickness of the base 22. Likewise, the width W may be selected accordingly. The channels 60 can have a width W of between about 0.1 mm and about 5 mm (e.g., 1.2 mm) and/or a depth D of between about 25% and about 75% of the thickness of the outsole 20. For example, for an outsole 20 having a thickness of 3.5 mm, the channel 60 may have a depth D of between about 0.8 mm and about 2.6 mm (e.g., a depth D of 1 mm, 2 mm, or 2.5 mm). The greater the depth and width of the channel 60, the greater the localized flexibility in the corresponding region of the outsole 20, and the easier the second tread 50 can move upward.

Alternatively, as shown in fig. 9-12, the outsole 20 may include a plurality of ribs 70 extending downwardly from the base 22 of the outsole 20. The rib 70 surrounds or encircles the flange 56 of each second tread 50. The cross-section of the ribs 70 may be linear, curved, angled, segmented, circular, or polygonal. Each rib 70 includes a width and a height. The height may extend a distance from the base 22 of the outsole 20. The width and height of the ribs 70 may be selected to provide a desired amount of localized support in corresponding regions of the outsole 20.

The shape of the outsole 20 may change when a wearer exerts pressure on the shoe due to the weight of the wearer and contact with the ground surface while wearing the article of footwear 10. The change in shape of the outsole 20 may allow both the first and second

ground contacting surfaces

42, 54 to become ground contacting. More specifically, the second tread 50 is configured to move between an unloaded position (as shown in fig. 3-5) and a loaded position (as shown in fig. 8). In the unloaded position, the first tread 40 is disposed at a first distance D1 (the distance between the first ground contacting surface 42 and the base 22), and the second tread 50 is disposed at a second distance D2 (the distance between the second ground contacting surface 54 and the base 22). The unloaded position is associated with an unloaded and/or unworn position of the

tread

40, 50 and outsole 20.

The weight of the wearer of the article of footwear 10 causes both the first and

second treads

40, 50 to compress and move upward into a loaded position. In the loaded position, the first and second

ground contacting surfaces

42, 54 move toward the base 22 such that the first distance D1 is reduced to a third distance D3 and the second distance D2 is reduced to a fourth distance D4, as shown in fig. 8. It should be understood that the compression of the first tread 40 may be due, at least in part, to the weight of the wearer and the density of the first material. Accordingly, the difference between the unloaded first distance D1 and the loaded third distance D3 may not be significant or drastic.

The second tread 50 is configured to move solely upward toward the base 22 when the second ground contacting surface 54 engages the ground surface. The second tread 50 is moved at least partially upward into the midsole 18 to a loaded position, as shown in fig. 8. In the loaded position, the second tread 50 at least partially compresses the midsole 18 at least in an area above each second tread 50 (including the flange 56) to move the second tread 50 upward from the second distance D2 to a fourth distance D4. Additionally, the channel 60 surrounding each second tread 50 provides the outsole 20 with localized flexibility such that each second tread 50 may more easily move upward toward the base 22. Thus, second ground contacting surface 54 moves upward from base 22 toward third distance D3, thus distributing ground forces across both first tread 40 and second tread 50. For example, the second tread 50 may be moved upward into the midsole 18 a distance of about 0.1 mm to 5.0 mm to distribute ground forces across both the first tread 40 and the second tread 50. Alternatively, the second tread 50 may be moved upward into the midsole a distance of about 0.5 mm to 1.5 mm. Further, the difference between the unloaded second distance D2 and the loaded fourth distance D4 may be greater than the difference between the unloaded first distance D1 and the loaded third distance D3.

In the loaded position, as shown in fig. 8, second ground contacting surface 54 is substantially planar with first ground contacting surface 42, or about 0 mm below first ground contacting surface 42, and third distance D3 and fourth distance D4 of respective first and

second treads

40, 50 may be substantially equal. When the second tread 50 is disposed in the loaded position, the second material of the second tread 50 is less worn by the ground surface than if the second tread 50 were retained at the second distance D2 when the ground force was applied. This may improve traction on various surfaces, and may also improve wear resistance of the second material on hard surfaces (e.g., road surfaces) before and after participating in footwear-appropriate activities.

It should be understood that, given the particular weight of the wearer of the article of footwear 10, both the first tread 40 and the second tread 50 may compress the midsole, and both

treads

40 and 50 may move a distance upward toward the base 22. Because both the first and

second treads

40 and 50 are composed primarily of the first material, the first and

second treads

40 and 50 will move substantially the same distance and the first and second

ground contacting surfaces

42 and 54 will remain substantially flat or flush with each other.

As noted above, the upper portions of the

treads

40, 50 may be constructed of a first material, whereas the first layer 52 of the second tread 50 underlying the first material may be constructed of a second material different from the first material. The selection of these materials may be based on the performance characteristics of the materials in terms of providing rigidity, wear resistance, and traction. The first material of the first tread 40 and the second tread 50 has a first hardness. The first layer 52 of the second tread 50 is composed of a second material and has a second hardness, and the midsole 18 is composed of a third material having a third hardness. The first hardness is equal to or greater than the third hardness. The choice of material hardness provides that the midsole 18 is softer than the main portion of the

tread

40, 50, such that the midsole 18 compresses first and more than the

tread

40, 50. This helps recess the second tread 50 upwardly into the midsole 18 so that the second ground contacting surface 54 is even with the first ground contacting surface 42.

The treads 40, 50 cause friction between the sole component 14 and the ground or surface with which it contacts to provide support and stability to the wearer of the article of footwear during various activities and sports. Accordingly, the traction of a particular material must also be considered. Higher density, stiffer materials generally provide greater wear resistance, but are more slippery and do not provide as good traction. Conversely, a lower density, softer material generally provides better traction, but is itself softer and provides less wear resistance.

The first material from which the first ground-contacting surface 42 is made has a first coefficient of static friction. The second material comprising the second ground contacting surface 52 and the first layer 52 has a second coefficient of static friction. The second coefficient of static friction is greater than the first coefficient of static friction. The second material provides improved traction with its higher static coefficient of friction, but is more susceptible to wear from the ground surface and less wear resistant. The ability of the second tread 50 to move upward toward the base 22 also helps reduce wear of the second tread 50. The wear of the second material of second ground contacting surface 54 of second tread 50 by the ground surface is less than the wear of the second material when the ground force is applied if second ground contacting surface 54 remains in its unloaded position (second distance D2).

Non-skid tests may be performed to determine the skid index of the different treads used in the outsoles of the embodiments herein to thereby evaluate tread compounds that are conducive to traveling over icy terrain or frozen bodies of water. One Method for testing Footwear Slip resistance is ASTM F2913-17, Standard Test Method for Measuring the Coefficient of Friction for Evaluation of the Footwear and Test Surfaces/floors Using a wheel Shoe Tester (Standard Test Method for Measuring Coefficient of Friction to evaluate Footwear and Test Surfaces/floors for Slip Performance). The anti-slip test may be performed using a tribometer (also called a slip meter), which is an instrument that measures the degree of friction between two friction surfaces. The tribometer simulates the biomechanical parameters of a human walking gait and replicates the human walking heel strike (e.g., using a leg and ankle device). The non-skid test may be performed on the first and

second treads

40, 50 and representative materials herein under wet and dry conditions to measure the coefficient of friction between the tread and a metal surface. The ratio of the non-skid properties of the second tread 50 (comprising the second material of the first layer 52) to the non-skid properties of the first tread 40 may optionally be at least 2: 1, further optionally about 3: 1.

different regions of sole assembly 14 may have particular characteristics designed and strategically positioned to accommodate wear, tear, wear, and forces specific to each region of sole assembly 14. For example, the first and

second treads

40, 50 may be interspersed among one another, an example of which is depicted in fig. 1. The positioning of the second tread 50 may be specifically strategically positioned to provide additional traction on specific areas on the bottom of the shoe where traction is important and/or relevant during certain circumstances. For example, it may be advantageous to place the second tread 50 under the ball of the wearer's foot. This is a high pressure area under the foot and, therefore, may take advantage of the increased traction provided by the second tread 50. Second tread 50 may also be placed in heel region 38 of the article of footwear 10 and may be positioned in any suitable configuration on the outsole and in any region of the sole assembly.

The shape and orientation of the

treads

40, 50 disclosed and illustrated herein may be asymmetric and/or irregular. This may mean that the purpose of shape and orientation is not just for aesthetic purposes. For example, the placement of the second tread 50 may indicate that applicants have found increased traction in this area to be beneficial. Furthermore, the placement of the first tread 40 may indicate that applicants have found greater wear resistance in this region to be beneficial.

Footwear 10 as described herein provides a balanced approach to providing both good traction and good wear resistance to the outsole. Articles of footwear 10 include a sole construction configured to provide improved traction for traversing wet, slippery, and/or icy terrain while providing good wear resistance for wear on hard surfaces. The different durometer materials of the outsole, in combination with the ability of the second tread to move at least partially up into the midsole, provide good wear resistance while still providing excellent traction on icy terrain features, particularly those that are wet and slippery.

Directional terms such as "vertical," "horizontal," "top," "bottom," "upper," "lower," "inner," "inward," "outer," and "outward" are used to help describe the invention based on the orientation of the embodiments shown in the drawings. The use of directional terms should not be construed to limit the invention to any particular orientation.

The above description is that of the current embodiment of the invention. Various modifications and changes may be made without departing from the invention in its broader aspects and as set forth in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. The present disclosure is presented for illustrative purposes and should not be construed as an exhaustive description of all embodiments of the invention or to limit the scope of the claims to the particular elements shown or described in connection with these embodiments. For example and without limitation, any individual element of the described invention may be replaced by an alternative element that provides substantially similar functionality or otherwise provides sufficient operation. This includes, for example, optional elements that are currently known, such as those that may be currently known to those skilled in the art, as well as optional elements that may be developed in the future, such as those that may be considered optional by those skilled in the art at the time of development. Further, the disclosed embodiments include a number of features that are consistently described and that can cooperatively provide a set of benefits. The present invention is not limited to only those embodiments which include all of these features or which provide all of the described benefits, except to the extent explicitly set forth in the issued claims. Any reference to an element of a claim in the singular, for example, using the articles "a," "an," "the," or "said," is not to be construed as limiting the element to the singular. Any reference to an element of the claims such as "X, Y and at least one of Z" is intended to include either X, Y or Z individually, and any combination of X, Y and Z (any number of units within such combinations), such as X, Y, Z; x, Y, respectively; x, Z, respectively; and Y, Z.

Claims

1. An article of footwear comprising:

a shoe upper; and

an outsole coupled to the upper, the outsole including a first tread and a second tread extending downwardly from the first tread, the outsole defining a base on a lower surface thereof, the lower surface extending between the first and second treads;

wherein the first tread is comprised of a first material, the first tread defining a first ground contacting surface spaced a first distance below the base;

wherein the second tread is composed of the first material and includes a layer of a second material below the first material, the second material having a lower wear resistance than the first material,

wherein the second tread defines a second ground contacting surface spaced below the base a second distance that is greater than the first distance such that the second ground contacting surface of the second tread extends below the first ground contacting surface of the first tread,

wherein the second tread is configured to move upward toward the base when the second ground contacting surface engages a ground surface such that the second ground contacting surface moves upward from the base toward the first distance to distribute ground forces on both the first tread and the second tread,

thus, the wear of the second material of the second tread by the ground surface is less than the wear of the second material when the second tread remains at the second distance when a ground force is applied.

2. The article of footwear according to claim 1,

wherein the second distance of the second ground contacting surface is 0.1 mm to 5.0 mm greater than the first distance of the first ground contacting surface.

3. The article of footwear according to claim 1, the outsole comprising:

a plurality of first treads and a plurality of second treads, and

a plurality of channels defined in the base portion,

wherein each of the plurality of channels surrounds an upper end of one of the plurality of second treads.

4. The article of footwear according to claim 3, comprising:

a midsole disposed above an upper surface of the outsole.

5. The article of footwear according to claim 4,

wherein the midsole is constructed of a third material having a third hardness,

wherein the first material of the first and second plurality of treads has a first hardness, and the first hardness is equal to or greater than the third hardness.

6. The article of footwear according to claim 5,

wherein each of the plurality of channels surrounding each of the plurality of second treads provides the outsole with localized flexibility such that each of the plurality of second treads is movable upward toward the base when the second ground contacting surface engages a ground surface.

7. The article of footwear according to claim 6,

wherein, due to a weight of a wearer of the article of footwear, the second plurality of treads move upward into the midsole, at least partially compressing the midsole.

8. The article of footwear according to claim 7,

wherein the second plurality of treads move upward into the midsole a distance of 0.1 mm to 5.0 mm to distribute ground forces over both the first plurality of treads and the second plurality of treads.

9. The article of footwear according to claim 1,

wherein a ratio of the first distance to the second distance is at least 1: 1.1.

10. an article of footwear comprising:

a shoe upper;

a midsole; and

an outsole coupled to the upper and disposed below the midsole, the outsole comprising:

a plurality of first treads extending downwardly from a lower surface of the outsole, an

A plurality of second treads extending downwardly from a lower surface of the outsole;

wherein the first plurality of treads are comprised of a first material having a first coefficient of static friction, the first plurality of treads defining a first ground-contacting surface;

wherein the plurality of second treads are comprised of the first material and include a layer of a second material below the first material, the second material having a second coefficient of static friction and defining a second ground contacting surface,

wherein the second static coefficient of friction is greater than the first static coefficient of friction and the second ground contacting surface is disposed 0.1 mm to 5.0 mm below the first ground contacting surface,

wherein, due to the weight of a wearer of the article of footwear, the second plurality of treads move at least partially upward into the midsole, compressing the midsole at least in an area above the second plurality of treads until the second ground contacting surface moves upward such that the second ground contacting surface is substantially 0 mm below the first ground contacting surface.

11. The article of footwear according to claim 10,

wherein the outsole includes a rib extending from the outsole and surrounding each of the plurality of second treads.

12. The article of footwear according to claim 10,

wherein the first material has a first hardness, the second material has a second hardness, and the midsole is made of a third material having a third hardness,

wherein the first hardness and the third hardness are different from each other.

13. The article of footwear according to claim 12,

wherein the third hardness is greater than the first hardness.

14. The article of footwear according to claim 13,

wherein the plurality of second treads compress the midsole until the second ground contacting surface is substantially planar with the first ground contacting surface,

whereby ground forces are distributed across both the first and second plurality of treads and the second material of the second plurality of treads has less wear from the ground surface than if the second plurality of treads were not at least partially moved upward into the midsole when ground forces were applied.

15. The article of footwear according to claim 14,

wherein the outsole defines a base on a lower surface thereof, the first ground-contacting surface of the first tread is spaced a first distance below the base, and the second ground-contacting surface of the second tread is spaced a second distance below the base, and a ratio of the first distance to the second distance is at least 1: 1.1.

16. an article of footwear comprising:

a shoe upper;

a middle sole, and

an outsole coupled to the upper, the outsole comprising:

a tread arrangement including a plurality of first treads interspersed among a plurality of second treads, an

A plurality of channels recessed into a lower surface of the outsole, wherein one of the plurality of channels surrounds an upper end of each of the plurality of second treads;

wherein the plurality of first treads are composed of a first material and define a first ground-contacting surface,

wherein the plurality of second treads are comprised of the first material and a layer of a second material underlying the first material, the second material defining a textured traction surface and a second ground contacting surface, the second material having a lower wear resistance than the first material,

wherein the second ground contacting surface is disposed 0.25 mm to 2.5 mm below the first ground contacting surface,

wherein, due to the weight of a wearer of the footwear, when the outsole engages the ground surface, the plurality of second treads move upward a distance of 0.25 mm to 2.5 mm into the midsole, thereby compressing the midsole at least in an area above the plurality of second treads such that the second ground-contacting surface is substantially flush with the first ground-contacting surface, thereby distributing ground forces on both the plurality of first treads and the plurality of second treads.

17. The article of footwear according to claim 16,

wherein the plurality of channels surrounding the plurality of second treads provide localized flexibility to the outsole such that each of the plurality of second treads is at least partially movable upward into the midsole.

18. The article of footwear according to claim 16,

wherein the first material has a first static coefficient of friction and the second material has a second static coefficient of friction that is greater than the first static coefficient of friction.

19. The article of footwear according to claim 18,

wherein the second material of the plurality of second treads has less wear by the ground surface when the second ground contacting surface is substantially flush with the first ground contacting surface than when the second ground contacting surface extends below the first ground contacting surface.

20. The article of footwear according to claim 16,

wherein the midsole is constructed of a third material having a third hardness,