ARTICLE OF FOOTWEAR WITH A LIGHTWEIGHT FOAM MIDSOLE

Abstract

An article of footwear is disclosed that includes an upper element and a sole structure secured to the upper element. The sole structure further comprises a midsole element that defines a plurality of indentations extending through a polymer foam material from a first surface to a second surface. The plurality of indentations comprising at least a first set of indentations and second set of indentations. The first set of indentations extending downwards from an upper surface; whereas, a plurality of second indentations extending upwards from a lower surface. The first set of indentations being offset from the second set of indentations.

Description

FIELD OF THE INVENTION

The present invention relates to footwear. The invention concerns, more particularly, an article of footwear with a plurality of indentations extending in a substantially vertical direction through a midsole.

BACKGROUND

A conventional article of athletic footwear includes two primary elements, an upper and a sole structure. The upper and the sole structure operate cooperatively to provide a comfortable structure that is suited for a variety of activities such as walking and running. The upper provides a covering for the foot that securely receives and positions the foot with respect to the sole structure. In addition, the upper may have a configuration that protects the foot and provides ventilation, thereby cooling the foot and removing perspiration. The sole structure is secured to a lower surface of the upper and is generally positioned between the foot and the ground. In addition to attenuating ground reaction forces, the sole structure may provide traction and control foot motions.

Current sole structure designs, however, provide a large portion of the overall weight of the athletic footwear. Heavier athletic footwear directly impacts comfort of the wearer and decrease performance during a multitude of activities such as running and walking. Current sole structure designs have focused on using lighter weight materials in the design of the sole structure to reduce the overall weight of the athletic footwear.

The sole structure of athletic footwear generally exhibits a layered configuration that includes a comfort-enhancing insole, a resilient midsole formed from a polymer foam material, and a ground-contacting outsole that provides both abrasion-resistance and traction. The midsole is the primary sole structure element that attenuates ground reaction forces and controls foot motions. Suitable polymer foam materials for the midsole include ethylvinylacetate or polyurethane that compress resiliently under an applied load to attenuate ground reaction forces. Conventional polymer foam materials are resiliently compressible, in part, due to the inclusion of a plurality of open or closed cells that define an inner volume substantially displaced by gas. The polymer foam materials of the midsole may also absorb energy when compressed during ambulatory activities.

The midsole may be formed from a unitary element of polymer foam that extends throughout the length and width of the footwear. With the exception of a thickness differential between the heel and forefoot areas of the footwear, such a midsole exhibits substantially uniform properties in each area of the sole structure.

Therefore, there is a need in the art for athletic footwear that overcomes the disadvantages of prior athletic footwear by providing a wearer with a lightweight sole structure in order to reduce the overall weight of the athletic footwear.

SUMMARY

The invention relates to an article of footwear having an upper and a sole structure secured to the upper. The sole structure includes a midsole element. The midsole element extends through a portion of a longitudinal length of the sole structure and from a lateral side to a medial side of the sole structure. The midsole element is formed from a polymer foam material and has a first surface and an opposite second surface. The midsole element defines a plurality of indentations extending through the polymer foam material and from the first surface to the second surface. The midsole element having a plurality of first indentations that extend downwards from an upper surface and a plurality of second indentations that extend upwards from a lower surface, the indentations being offset from one another.

The indentation may extend in a substantially vertical direction and exhibit various shapes and configuration such as a hexagonal, triangular, square, pentagonal, or round, for example. The indentations may also form a tessellation or have a tapered structure. In an aspect of the invention, the dimensions of the indentations may vary throughout the midsole element.

The advantages and features of novelty characterizing the present invention are pointed out with particularity in the appended claims. To gain an improved understanding of the advantages and features of novelty, however, reference may be made to the following descriptive matter and accompanying drawings that describe and illustrate various embodiments and concepts related to the invention.

DESCRIPTION OF THE DRAWINGS

The foregoing summary as well as the following detailed description, will be better understood when read in conjunction with the accompanying drawings.

FIG. 1 illustrates a lateral side elevational view of an article of footwear having a midsole in accordance with an aspect of the invention.

FIG. 2 illustrates a medial side elevational view of an article of footwear having a midsole in accordance with an aspect of the invention.

FIG. 3 illustrates a top view of a midsole in accordance with an aspect of the invention.

FIG. 4 illustrates another top view of a midsole in accordance with an aspect of the invention.

FIG. 5 illustrates a bottom view of the midsole shown in FIG. 3 in accordance with an aspect of the invention.

FIG. 6 illustrates a bottom view of the midsole shown in FIG. 4 in accordance with an aspect of the invention.

FIG. 7 illustrates an outsole in accordance with an aspect of the invention.

FIG. 8 is a cross-sectional view of an embodiment of the midsole of the invention as defined by section line AA in FIG. 4 in accordance with an aspect of the invention.

FIG. 9 is another cross-sectional view of an embodiment of the midsole of the invention as defined by section line BB in FIG. 4 in accordance with an aspect of the invention.

FIG. 10 illustrates a bottom view of an article of footwear with various indentations of different sizes and shapes in accordance with an aspect of the invention.

FIGS. 11-17 are top plan views of portions of alternate midsole configurations in accordance with in accordance with an aspect of the invention.

FIG. 18 is top plan view of a midsole configuration illustrating hexagonal indentations having a greater variance in dimensions throughout the length of midsole in accordance with an aspect of the invention.

DETAILED DESCRIPTION

The following discussion and accompanying figures disclose an article of footwear having a midsole element in accordance with the present invention. Concepts related to midsole element are disclosed with reference to footwear having a configuration that is suitable for various athletic activities, including running, for example. The invention is not solely limited to articles of footwear designed for running, however, and may be applied to a wide range of athletic footwear styles that include basketball shoes, training shoes, walking shoes, hiking shoes and boots, tennis shoes, volleyball shoes, soccer shoes, and football shoes. In addition to athletic footwear, concepts related to the invention may be applied to footwear that is generally considered to be non-athletic (e.g., dress shoes, sandals, and work boots) or footwear serving a medical or rehabilitative purpose. Accordingly, one skilled in the relevant art will appreciate that the concepts disclosed herein apply to a wide variety of footwear styles, in addition to the specific footwear style discussed in the following material and depicted in the accompanying figures.

An article of footwear 100, as depicted in FIG. 1, includes an upper 120 and a sole structure 130 that are suitable for a variety of athletic activities, including running, for example. Upper 120 may have a generally conventional configuration incorporating a plurality of material elements (e.g., textiles, foam, and leather) that are stitched or adhesively bonded together to form an interior void for securely and comfortably receiving a foot. The material elements may be selected and located with respect to upper 120 in order to selectively impart properties of durability, air-permeability, wear-resistance, flexibility, and comfort, for example. Moreover, upper 120 may comprise a plurality of air slots (not shown) throughout upper 120 to increase air flow through upper 120 and decrease weight of upper 120. In addition, upper 120 may include a lace that is utilized in a conventional manner to modify the dimensions of the interior void, thereby securing the foot within the interior void and facilitating entry and removal of the foot from the interior void. The lace may extend through apertures in upper 120, and a tongue portion of upper 120 may extend between the interior void and the lace. Accordingly, upper 120 may exhibit a substantially conventional configuration within the scope of the present invention. In addition, the upper 120 may incorporate a sock liner (not depicted) that is positioned within the interior void in upper 120 and located to correspond with a plantar (i.e., lower) surface of the foot, thereby enhancing the comfort of footwear 100.

For aid in describing various aspects of the invention, footwear 100 may be divided into three general regions: a forefoot region 111, a midfoot region 112, and a heel region 113, as illustrated in FIG. 1. Forefoot region 111 generally includes portions of footwear 100 corresponding with the toes and the joints connecting the metatarsals with the phalanges. Midfoot region 112 generally includes portions of footwear 100 corresponding with the arch area of the foot, and heel region 113 corresponds with rear portions of the foot, including the calcaneus bone. Footwear 100 also includes a lateral side 114 and a medial side 214 (FIG. 2). Regions 111-113 and sides 114 and 214 are not intended to demarcate precise areas of footwear 100. Rather, regions 111-113 and sides 114 and 215 are intended to represent general areas of footwear 100 to aid in the following discussion.

A moderation plate 135 may be positioned between the sole structure 130 and the upper 120. Moderation plate 135 may comprise an upper portion 137 and a lower portion 138. Moderation plate 135 may be comprised of a full nylon plate to provide additional support to the wearer of footwear 100. Those skilled in the art will realize that moderation plate 135 may be composed of other materials such as numerous polymers.

Sole structure 130 may include various elements such as a midsole 141 and an outsole 143. Midsole 141 may include an upper midsole surface 151 and a lower midsole surface 152. The upper midsole surface 151 may be secured to a lower portion 138 of moderation plate 135 and attenuate ground reaction forces as sole structure 130 and the moderation plate 135 are compressed between the foot and the ground.

Outsole 143 may be secured to a lower midsole surface 152. Outsole 143 may be formed from a durable and abrasion-resistant material, such as rubber, that may be textured to define various protrusions for providing traction. Although outsole 143 is depicted as a unitary element extending through each of regions 111-113, in other aspects of the invention outsole 143 may be two or more separate elements.

FIG. 2 illustrates a medial side elevational view 214 of footwear 100. As described above with respect to FIG. 1, footwear 100 includes an upper 120 and a sole structure 130 that are suitable for a variety of athletic activities, including running, for example. For aid in describing various aspects of the invention, footwear 100 may be divided into three general regions: a forefoot region 111, a midfoot region 112, and a heel region 113, as illustrated in both FIGS. 1 and 2.

As shown in FIG. 2, the forefoot region 111 may include at least one crown 231 to provide additional resistant to abrasion. As those skilled in the art will realize, a wearer of footwear 100 may during certain athletic activities place additional force on the medial forefoot portion of footwear 100. The inclusion of at least one crown 231 on the medial forefoot of footwear 100 may decrease wear on that portion of footwear 100.

As further illustrated in FIG. 2, moderation plate 135 may be positioned between the sole structure 130 and the upper 120. In various aspects of the invention, the entire moderation plate 135 may not be completely visible to an observer as midsole 141 may partially obscure moderation plate 135. In other aspects of the invention, moderation plate 135 may be composed of various separate sections which may not be unitary in construction.

Midsole 141 may be formed from a polymer foam material, such as polyurethane or ethylvinylacetate, that extends along at least a portion of the longitudinal length of footwear 100 (i.e., through regions 111-113) and also from at least a portion of lateral side 114 to medial side 214. In certain aspects of the invention, midsole 141 may be formed from two or more discrete material elements (i.e., a forefoot element and a heel element), or midsole 141 may be formed from a dual-density foam (i.e., lateral side 114 may be formed from a softer foam than medial side 214). In another aspect of the invention, dual-density foam in the form of foam inserts may be located in various portions of midsole 141. For example, midsole 141 may be comprised of foam inserts 180 which are illustrated in FIGS. 1 and 2. The dual-density foam may provide a wearer with improved force attenuation properties.

In an aspect of the invention, various midsoles are depicted in FIGS. 3-7. FIGS. 3 and 5 depict a midsole 350 which includes an upper midsole surface 351 (FIG. 3) and an opposite lower midsole surface 552 (FIG. 5). A plurality of indentations 380 extend between the upper midsole surface 351 and the opposite lower midsole surface 552. The plurality of indentations 380 may extend through midsole 350 in a substantially vertical direction. In addition, midsole 350 may taper downward between heel region 113 and forefoot region 111. Moreover, in one aspect of the invention, the number of indentations 380 in the forefoot region 111 may be greater than a number of indentations 380 in a midfoot region 112 or a heel region 113 of midsole 350. In an alternative embodiment, the number of indentations in the heel region 113 may be greater than the number of indentations 380 in the midfoot region 112 or the forefoot region 111.

Midsole 350 may be manufactured through a molding process, wherein a polymer material is injected into a mold having the shape of midsole 350. The various indentations 380 may be formed by projections that extend between upper and lower portions of the mold. The configuration of indentations 380 may vary significantly within the scope of the present invention. For example, indentations 380 may exhibit constant dimensions between upper midsole surface 351 and lower midsole surface 552. In another aspect of the invention, indentations 380 may exhibit tapered dimensions between upper midsole surface 351 and lower midsole surface 552.

For instance, FIGS. 4 and 6 illustrate an aspect of the invention in which a first set of indentations 680 are rectangular in shape. In FIGS. 4 and 6, a midsole 450 is shown which includes an upper midsole surface 451 (FIG. 4) and an opposite lower midsole surface 652 (FIG. 6). The plurality of indentations 480 extend between the upper midsole surface 451 and the opposite lower midsole surface 652. In addition, a second set of indentations 680 offset from the first set of indentations 480 may extend between the lower midsole surface 652 and the opposite upper midsole surface 451. The plurality of indentations 680 may extend through midsole 450 in a substantially vertical direction. In addition, the plurality of indentations 680 may also have a tapered configuration. The tapered configuration of indentations 680 may be opposite of the tapered configuration of indentations 480. For example, FIGS. 8 and 9 illustrate an aspect of the invention, wherein, indentations 680 have a tapered configuration. In particular, FIG. 8 illustrates a cross section AA taken from FIG. 4 of midsole 450 in the forefoot region of the footwear; whereas, FIG. 9 illustrates a cross section BB taken from FIG. 4 of midsole 450 in the heel region. As may be seen in FIGS. 8 and 9, the dimensions of indentations 680 adjacent to upper midsole surface 451 are less than the dimensions of indentations 680 adjacent to lower midsole surface 652. That is indentations 680 may taper inward between lower midsole surface 652 and upper midsole surface 451. As shown in FIG. 4, the tapered indentations 482 may appear as circular penetrations as they taper in dimension from lower midsole surface 652 to upper midsole surface 451 (FIGS. 8 & 9).

In an aspect of the invention, tapered indentations such as indentations 480 may not be visible on a lower midsole surface, such as lower midsole surface 652, as an outsole may mask penetration of midsole 450. The outsole may be secured to the lower midsole surface. Outsole 143 may be formed from a durable and abrasion-resistant material, such as rubber, that may be textured to define various protrusions for providing traction. For example, an outsole 702 as shown in FIG. 7 may hide penetration of a plurality of indentations through a midsole from an upper midsole surface to a lower midsole surface. The covered indentations may be offset by a plurality of indentations 780 extending from a lower midsole surface to an upper midsole surface.

FIG. 10 illustrates another aspect of the invention in which indentations may vary in size depending of the specific location of the indentations. In FIG. 10, a sole view of an article of footwear 1000 is illustrated in which the number of indentations 1180 in the forefoot region 1110 is greater than the number of indentations 1182 in a midfoot region 1120 or a number of indentations 1184 in a heel region 1130 of footwear 1000. Further as illustrated in FIG. 7, the indentations (1180, 1182, and 1184) found on footwear 1000 may vary in shape and dimension across the various regions or within each of the regions. For example in forefoot region 1110, a first indentation 1130 may be wider than a second indentation 1131. Similarly, indentation 1130 of forefoot region 1110 may vary in shape and dimension from midfoot indentation 1132 or heel indentation 1134. The various sized indentations may be used to vary the weight of the footwear 1000 in specific regions in order to enhance overall performance of footwear 1000.

As those skilled in the art will realize, the shapes and sizes of indentations may also vary significantly within the scope of the present invention to include numerous other shapes as depicted in FIGS. 11-18. For example, a midsole 40 may exhibit triangular or square shape indentations 43, as depicted in FIGS. 11 and 12. An advantage of triangular and square shapes relates to the manner in which the various indentations 43 may be arranged. More particularly, indentations 43 having hexagonal, triangular, or square shapes may be arranged to effectively form a tessellation. As utilized herein, the term “tessellation” is defined as a covering of an area, without significant gaps or overlaps, by congruent plane figures of one type or a plurality of types. Accordingly, indentations 43 having hexagonal, triangular, or square shapes, as viewed in either an upper surface or lower surface, may be arranged such that edges of the various indentations 43 are adjacent to edges of other indentations 43 and few significant gaps are formed between the indentations 43.

Indentations 43 also comprise a variety of other configurations and combinations. Referring to FIG. 13 indentations having a mixture of hexagonal, triangular, and square configurations are arranged to form a tessellation. Indentations 43 having a chevron configuration or an irregular configuration may also be arranged to form a tessellation, as depicted in FIGS. 14 and 15. Accordingly, indentations 43 may form a tessellation when exhibiting non-regular geometrical or non-geometrical configurations. In other embodiments, indentations 43 may exhibit pentagonal or round configurations, as depicted in FIGS. 16 and 17. Accordingly, indentations 43 may exhibit a variety of configurations within the scope of the present invention.

Each of indentations 43 may exhibit similar dimensions or may also be configured to have a variety of dimensions. Referring to FIG. 18, midsole 40 defines a variety of indentations 43 with hexagonal configurations. Indentations 43 exhibit a greater variance in dimensions throughout the length of midsole 40. In heel region 113, one of indentations 180 is significantly larger than other indentations such as indentation 185. The larger indentation 180 is positioned to correspond in location with a calcaneus bone of a foot. That is, the larger indentation 180 will be generally positioned under the calcaneus bone of a foot. This configuration may be utilized, for example, to impart greater compliance to heel region 113 of midsole 40 and particularly the area under the calcaneus.

In addition, different shapes and dimensions of indentations may be used in the various different regions of the article of footwear to impart various advantages to and article of footwear. For example, using different patterns and sizes of indentations may decrease the compressibility of specific areas of a sole structure or impart additional stability or otherwise control foot motions, such as the degree of pronation. For example, it is well know in the art that the typical motion of the foot during running proceeds as follows: Initially, the heel strikes the ground, followed by the ball of the foot. As the heel leaves the ground, the foot rolls forward so that the toes make contact, and finally the entire foot leaves the ground to begin another cycle. During the time that the foot is in contact with the ground and rolling forward, it also rolls from the outside or lateral side to the inside or medial side, a process called pronation. While the foot is air-borne and preparing for another cycle, the opposite process, called supination, occurs. In order to impart a suitable degree of ground reaction force attenuation upon contact of the heel with the ground, various positioned and sized indentations may be placed in heel region of the article of footwear. Also, to increase stability and the control of foot motions, the relative location and size of the indentations may be utilized throughout the forefoot and midfoot regions of the article of footwear.

The present invention is disclosed above and in the accompanying drawings with reference to a variety of embodiments. The purpose served by the disclosure, however, is to provide an example of the various features and concepts related to the invention, not to limit the scope of the invention. One skilled in the relevant art will recognize that numerous variations and modifications may be made to the embodiments described above without departing from the scope of the present invention, as defined by the appended claims.

Claims

1. An article of footwear comprising:

an upper;

a solid moderation plate attached the upper, the solid moderation plate having a top surface and a bottom surface; and

a sole structure comprising: a midsole having a first surface and an opposite second surface, the midsole element extending substantially through a longitudinal length of the sole structure and from a lateral side to a medial side of the sole structure, the midsole element defining a plurality of indentations extending through the polymer foam material and from the first surface to the second surface; and

an outsole attached to the opposite second surface.

2. The article of footwear recited in claim 1, wherein the indentations have a hexagonal shape.

3. The article of footwear recited in claim 1, wherein a shape of the indentations is selected from a group consisting of triangular, square, pentagonal, and round.

4. The article of footwear recited in claim 1, wherein the indentations form a tessellation.

5. The article of footwear recited in claim 1, wherein the indentations are tapered.

6. The article of footwear recited in claim 1, wherein dimensions of the indentations vary throughout the midsole element.

7. The article of footwear recited in claim 1, wherein the indentations have a substantially vertical orientation.

8. The article of footwear recited in claim 1, wherein the plurality of indentations comprises conical indentations.

9. An article of footwear having an upper, a moderation plate, and a sole structure, the sole structure comprising:

an outsole; and

a midsole, the midsole in contact with the moderation plate and the upper, the midsole having a plurality of first indentations that extend downwards from an upper surface and a plurality of second indentations that extend upwards from a lower surface, the plurality of first indentations being offset from the plurality of second indentations.

10. The article of footwear recited in claim 9, wherein the moderation plate comprises a solid moderation plate.

11. The article of footwear recited in claim 9, wherein the indentations have a hexagonal shape.

12. The article of footwear recited in claim 9, wherein a shape of the indentations is selected from a group consisting of triangular, square, pentagonal, and round.

13. The article of footwear recited in claim 9, wherein the indentations form a tessellated configuration.

14. The article of footwear recited in claim 9, wherein the indentations are tapered.

15. The article of footwear recited in claim 9, wherein dimensions of the indentations vary throughout the midsole element.

16. The article of footwear recited in claim 9, wherein the indentations have a substantially vertical orientation.

17. An article of footwear comprising:

an upper;

a solid moderation plate attached to the upper, the moderation plate having a top surface and a bottom surface; and

a sole portion attached to the bottom surface of the moderation plate, the sole portion comprising: an outsole; and a midsole, the midsole having a plurality of first indentations that extend downwards from an upper surface and a plurality of second indentations that extend upwards from a lower surface, the plurality of first indentations being offset from the plurality of second indentations.

18. The article of footwear recited in claim 17, wherein the indentations are oriented to be substantially vertical.

19. The article of footwear recited in claim 17, wherein a shape of the indentations is selected from a group consisting of triangular, square, and hexagonal.

20. The article of footwear recited in claim 17, wherein the indentations are tapered.