ARTICLE OF FOOTWEAR WITH ENERGY RETURN SYSTEM

FIELD

[0001]The present disclosure generally relates to articles of footwear. More specifically, some embodiments relate to articles of footwear having an energy return system to provide cushioning and energy return in the sole.

BACKGROUND

[0002]Articles of footwear usually have sole structures that provide cushioning to the foot. Specifically, the amount and character of cushioning can be an important feature in athletic and other performance footwear. When an article of footwear contacts a surface, considerable forces may act on the article of footwear and, correspondingly, the foot. The sole therefore provides cushioning to the foot to protect it from these forces.

BRIEF SUMMARY

[0003]Some embodiments described herein relate to a sole for an article of footwear including a midsole formed of a resilient material, the midsole having a plurality of holes extending transversely therethrough from a medial sidewall of the midsole to a lateral sidewall of the midsole, and a resilient tube disposed within each of the holes. Each resilient tube has a wall thickness that varies in the transverse direction of the sole.

[0004]In some embodiments described herein, the wall thickness is thinner at a midpoint of each of the tubes and thicker at a medial end and a lateral end of each of the tube.

[0005]In some embodiments described herein, the inner diameter of each of the tubes decreases as the wall thickness increases in the transverse direction.

[0006]In some embodiments described herein, in the inner diameter of each of the tubes remains constant as the wall thickness varies in the transverse direction.

[0007]In some embodiments described herein, each of the tubes extends from the medial sidewall of the midsole to the lateral sidewall of the midsole.

[0008]In some embodiments described herein, the tubes have wall thickness varying in the longitudinal direction of the sole.

[0009]Some embodiments described herein relate to a sole for an article of footwear, including a midsole formed of a resilient material, the midsole having a plurality of holes extending transversely therethrough from a medial sidewall of the midsole to a lateral sidewall of the midsole, and a resilient tube disposed within each of the holes. Each resilient tube has a flange at each of a medial end and a lateral end thereof, and the flanges extend outside their respective hole and are disposed against the medial sidewall and the lateral sidewall of the midsole.

[0010]Some embodiments described herein relate to a sole for an article of footwear, including a midsole formed of a resilient material, the midsole having a plurality of holes extending transversely therethrough from a medial sidewall of the midsole to a lateral sidewall of the midsole, and a unitary cartridge of connected resilient tubes. One of the tubes is disposed within each of the holes, and the tubes are connected by connecting members of the cartridge that extend between adjacent tubes. The connecting members are spaced away from ends of the tubes and not visible from an exterior of the sole.

[0011]In some embodiments described herein, the unitary cartridge further includes a positioning tab disposed against a sidewall of the midsole.

[0012]Some embodiments described herein relate to a sole for an article of footwear, including a midsole formed of a resilient material, the midsole having a plurality of holes extending transversely therethrough from a medial sidewall of the midsole to a lateral sidewall of the midsole. A hardness of an inner surface of the holes is greater than a hardness of the rest of the midsole.

[0013]In some embodiments described herein, the holes are visible from the exterior of at least one of the medial sidewall and the lateral sidewall of the midsole.

[0014]In some embodiments described herein, medial and lateral ends of the tubes are visible from the exterior of at least one of the medial sidewall and the lateral sidewall of the midsole.

[0015]In some embodiments described herein, a hardness of the tube is greater than a hardness of the midsole.

[0016]In some embodiments described herein, the tube is more resilient than the midsole.

[0017]In some embodiments described herein, the tube includes a flange at a medial end and a lateral end.

[0018]In some embodiments described herein, the flanges are flush the medial sidewall and the lateral sidewall of the midsole.

[0019]In some embodiments described herein, the flanges are recessed from the medial sidewall and the lateral sidewall of the midsole.

[0020]In some embodiments described herein, the flange of each of the tube at the medial end is arranged a different vertical plane, and the flange of each of the tube at the lateral end is arranged a different vertical plane.

[0021]In some embodiments described herein, the tubes have varying lengths.

[0022]In some embodiments described herein, any two of the tubes are spaced by a distance to allow compression of the tubes.

BRIEF DESCRIPTION OF THE FIGURES

[0023]The accompanying drawings, which are incorporated herein and form part of the specification, illustrate embodiments of the present invention and, together with the description, further serve to explain the principles of the disclosure and to enable a person skilled in the relevant art(s) to make and use embodiments of the disclosure.

[0024]FIG. 1 is a side view of an article of footwear with an energy return system according to some embodiments.

[0025]FIG. 2 is a side view of an article of footwear with an energy return system according to some embodiments.

[0026]FIG. 3 is a side view of an article of footwear with an energy return system according to some embodiments.

[0027]FIG. 4 is a bottom view of an article of footwear with an energy return system according to some embodiments.

[0028]FIG. 5 is a bottom view of an article of footwear with an energy return system according to some embodiments.

[0029]FIGS. 6A-6O show tubes for an energy return system according to various embodiments.

[0030]FIG. 7 is an exploded view of a sole with an energy return system according to some embodiments

[0031]FIG. 8 is an exploded view of a sole with an energy return system according to some embodiments.

[0032]FIG. 9 is an exploded view of a sole with an energy return system according to some embodiments.

[0033]FIG. 10 is a perspective view of a sole with an energy return system according to some embodiments.

[0034]FIG. 11 is a perspective view of a sole with an energy return system according to some embodiments.

[0035]FIG. 12 shows an exploded view of a sole with energy return system according to some embodiments.

[0036]FIG. 13 shows a transparent window for an energy return system according to some embodiments.

[0037]FIG. 14 shows an exploded view of the energy return system of FIG. 10 with a shell according to some embodiments.

[0038]FIG. 15 is an exploded view of a sole with an energy return system according to some embodiments.

DETAILED DESCRIPTION

[0039]The present invention(s) will now be described in detail with reference to embodiments thereof as illustrated in the accompanying drawings. References to “one embodiment,” “an embodiment,” “some embodiments,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

[0040]The human foot possesses natural cushioning and rebounding characteristics, but the foot alone is incapable of effectively overcoming many of the forces encountered during every day activity. The soreness and fatigue associated with every day activity can aggregate on the foot and diminish the incentive for further activity. Proper footwear should complement the natural functionality of the foot, in part, by incorporating a sole structure (typically including an outsole, midsole and insole) that absorbs shocks and provides rebounding energy to cushion the foot.

[0041]To achieve adequate cushioning, many footwear soles are relatively thick and heavy, which can reduce the flexibility of the sole. Some other footwear soles also incorporate encapsulated air/fluid structures to provide cushioning, but such structures can be difficult and costly to design and manufacture. Therefore, a continuing need exists for innovations in providing cushioning to articles of footwear.

[0042]The aesthetic appeal of the article of footwear is also an important aspect, and can help convey the functionality and use of the article, as well as for marketing purposes. As such, the aesthetic of the sole may work in concert with its functionality. It is also desirable to use the aesthetic appearance of the footwear as a visual cue of its rebounding and cushioning functions.

[0043]Embodiments of the present disclosure provide soles incorporating an energy return system for an article of footwear that provides rebounding and cushioning effects to the foot without making the sole heavy and bulky or using encapsulated air/fluid (though they do not exclude the use of encapsulated air/fluid in other aspects of the article of footwear, including elsewhere in the sole or in the upper, for example).

[0044]In some embodiments, a number of hollow tubes formed of a resilient material (e.g., polyurethane, ethylene vinyl acetate, or thermoplastic polyurethane) can extend in the sole to provide rebounding energy. The tubes can be encapsulated by the sole and spaced at a distance which causes the sole material between the tubes to compress when forces are applied perpendicular to the sole (e.g. normal/perpendicular to the ground during impact, shear force during braking). When a forced is applied perpendicular to the sole (e.g., during a footstrike while a wearer is running), the sole material around the tubes is compressed, which provides cushioning and comfort to the wearer, while the tubes-due to their greater resilience-flex or compress to a lesser degree, not only providing support and resisting too much compression, but also providing a rebounding force against the direction of compression after the energy from the footstrike is absorbed, thereby returning some of the absorbed energy to the wearer through a spring-like effect. This can help promote a quick and efficient pace, and reduce fatigue when running.

[0045]In some embodiments, the sole is provided with negative spaces that resemble the structure of hollow tubes. The negative spaces can be holes extending through the sole. Due to their shape and structure, the negative spaces can perform a similar function as hollow tubes, as will be discussed in greater detail below.

[0046]Further, to improve aesthetic attractiveness and to help signal its functionality, in some embodiments, the sole has features that provide visual indications of the energy return system. For example, clear or transparent windows and shells around the sole can provide a direct view of the tubes or negative spaces. In some embodiments, the bottom surface of the sole can also be constructed to mimic the shape of hollow tubes. These can provide a visual cue to a consumer of the function of the energy return system, which can help them to understand the technology and use of the energy return system so that they can get the most out of it.

[0047]In FIG. 1, an article of footwear 10a having an energy return system can include an upper 100a, midsole 200a, and outsole 300a according to some embodiments is shown. In FIG. 2, an article of footwear 10b having an energy return system can include an upper 100b, midsole 200b, and outsole 300b according to some embodiments is shown. In FIG. 3, an article of footwear 10c having an energy return system can include an upper 100c, midsole 200c, and outsole 300c according to some embodiments is shown. It is noted that footwear 10a, 10b, and 10c are different embodiments of and can be collectively referred to herein as footwear 10; uppers 100a, 100b, and 100c are different embodiments of and can be collectively referred to herein as upper 100; midsoles 200a, 200b, and 200c are different embodiments of and can be collectively referred to herein as midsole 200; outsoles 300a, 300b, and 300c are different embodiments of and can be collectively referred to herein as outsole 300. It is also contemplated that footwear 10 may be any type of footwear in which the sole of the present invention may be desirable, including, but not limited to, walking shoes, running shoes, basketball shoes, court shoes, tennis shoes, training shoes, boots, and sandals. To the extent that only the left or right article of footwear 10 is described for a particular embodiment, a person of skill in the art would understood that an article of footwear 10 suitable for the other foot, even if not specifically described, may in some embodiments be a mirror image of the described article of footwear 10.

[0048]In some embodiments, midsole 200 may be attached to upper 100 in any conventional manner, and outsole 300 may be attached to midsole 200 in any conventional manner. In some embodiments, outsole 300 and midsole 200 may be molded into a unitary footwear 10, including upper 100, midsole 200, and outsole 300, can be divided into a forefoot portion 12, a midfoot portion 14, and a heel portion 16 along a longitudinal direction. These three portions, together, extend the entire length of the sole.

[0049]In some embodiments, upper 100 may be a typical athletic shoe upper comprising a fabric or a leather. In some embodiments, midsole 200 may be formed of an elastomeric material, for example, thermoplastic polyurethane (“TPU”), ethylene vinyl acetate (“EVA”), compression molded ethyl vinyl acetate (“CMEVA”), injection molded ethyl vinyl acetate (“IMEVA”), thermoplastic polyurethane (“PU”), polyether block amide (“PEBA”), thermoplastic polyester elastomer (“TPEE”), or other thermoplastic polymers. In some embodiments, outsole 300 may be formed of an abrasive resistant material and may include treads or any other means for providing traction.

[0050]To provide rebounding and cushioning effect, in some embodiments, tubes 400 having a generally circular cross-section and hollow body are provided. Tubes 400 can include any one or more of the embodiments discussed below with respect to FIGS. 6A-6M, and they are applicable to any of footwear 10a, 10b, and 10c.

[0051]In some embodiments, tubes 400 may be disposed within midsole 200 (e.g., FIG. 7), and midsole 200 may have cutouts 202 extending through midsole 200 that resemble the shape of tubes 400 to provide a stable physical structure for accommodating tubes 400. In some embodiments, cutouts 202 may be formed as holes extending through midsole 200 in the transverse direction, and tubes 400 may be encapsulated within holes 202. In some embodiments, tubes 400 may be seated between midsole 200 and outsole 300 (e.g., FIG. 8.), and midsole 200 and outsole 300 may each have cutouts 202 and cutouts 302 that resemble a portion of the shape of tubes 400 to provide a stable physical structure for accommodating tubes 400. Cutouts 202 and cutouts 302 may be grooves extending through midsole 200 and outsole 300 in the transverse direction. In some embodiments, when midsole 200 and outsole 300 are assembled, cutouts 202 and corresponding cutouts 302 may together form holes extending through midsole 200 and outsole 300 in the transverse direction to encapsulate tubes 400.

[0052]Tubes 400 may be formed of an elastomeric material, for example Hytrel, TPU, PEBA, or other thermoplastic polymers. In some embodiments, tubes 400 can have a hardness more than midsole 200. In some embodiments, tubes 400 can have a hardness of at least 40 D. A larger hardness of tubes 400 means that when tubes 400 are compressed under an applied force, it can help resist further compression of midsole 200, which has smaller hardness. Also, tubes 400 having larger hardness tend to return to their original shape after being deformed faster than midsole 200 having smaller hardness, thereby providing rebounding effect. In this way, tubes 400 can be said to have a greater resilience than midsole 200. In operation, energy is absorbed and temporarily stored when the tubes are compressed (e.g., by a footstrike while a user is running) and returns in the form of rebound energy when the force is lifted (e.g., as the footstrike progresses past its maximum downward force).

[0053]Tubes 400 can be manufactured by any suitable methods. For example, tubes 400 can be extruded, cast, injection molded, extrusion blow molded, additively manufactured. In some embodiments, tubes 400 can be molded with a single polymer, and in some embodiments, tubes 400 can be co-molded with multiple polymers. In some embodiments, tubes 400 can be manufactured by a multi-step process. For example, tubes 400 can be first extrusion blow molded and then trimmed to desired geometry.

[0054]In alternative embodiments, instead of having tubes 400 to provide rebounding and cushioning effect, midsole 200 can have negative spaces 602 that provide similar functions as tubes 400. Negative spaces 602 can resemble the shape and the placement of tubes 400 as described below and generally be through holes extending the lateral direction of midsole 200. The embodiments incorporating negative spaces 602 are described in more detail below with references to FIG. 11.

[0055]Tubes 400 can be disposed in any location of footwear 10 that requires additional cushioning, and FIGS. 1-3 illustrates some exemplary placements of tubes 400. In an embodiment as shown in FIG. 1, footwear 10a can include tubes 400 disposed in heel portion 16 to focus their energy return properties at a wearer's heel. In another embodiment as shown in FIG. 2, footwear 10b can include tubes 400 disposed primarily in forefoot portion 12 to focus their energy return properties at a wearer's forefoot. In another embodiment as shown in FIG. 3, footwear 10c can include tubes 400 disposed throughout the entire length of footwear 10c to provide energy return properties along a wearer's foot as a whole.

[0056]When tubes 400 are disposed throughout the entire length of footwear 10, in some embodiments, tubes 400 may be evenly distributed throughout the length of footwear 10, such that the distance between two tubes 400 is the same throughout the length of footwear 10. In some other embodiments, tubes 400 may be more concentrated in a portion of footwear 10 (e.g., heel portion 16 and/or forefoot portion 12), such that the distance between two tubes 400 is smaller in the concentrated portion than the rest of footwear 10, to provide ideal cushioning and rebounding effect. For example, the more concentrated area can be stiffer than the less concentrated area. In some other embodiments, tubes 400 can be disposed in forefoot portion 12 or midfoot portion 14 only, or tubes 400 can be disposed in more than one portion of footwear 10, for example, tubes 400 can be disposed in both heel portion 16 and forefoot portion 12 or both heel portion 16 and midfoot portion 14.

[0057]Additionally, in some embodiments, structural characteristics of tubes 400 may vary throughout the length of footwear 10 to achieve different cushioning effects. For example, tubes 400 throughout the length of footwear 10 may have vary in size, wall thickness, shapes, or spacing from adjacent tubes. Structural characteristics of tubes 400 according to different embodiments are discussed in further details below with reference to FIGS. 6A-6M.

[0058]Tubes 400 may or may not be visible from the outside of footwear 10. For example, as shown in FIG. 3, while tubes 400 are disposed through the entire length of footwear 10c, only four of tubes 400 in heel portion 16 are visible through sidewall 204c of midsole 200c, and the rest of tubes 400 shown in phantom lines are not visible. In some embodiments, tubes 400 can be made visible by exposing one or both ends of tubes 400 through sidewall 204c of midsole 200c and/or sidewall 304c of outsole 300c, and tubes 400 are not visible when the both ends of a tube 400 are fully encapsulated within midsole 200c and/or outsole 300c. Midsole 200c and/or outsole 300c may also include transparent windows on sidewall 204c and/or side wall 304c to cover tubes 400c that are exposed. Visibility of tubes 400 provides a visual cue of the functioning of the energy return system. Additional features to provide visibility of tubes 400 are described below with respect to FIGS. 12-15.

[0059]Additional embodiments of outsole 300d and outsole 300e are shown in FIGS. 4 and 5. In outsole 300d and outsole 300e, tubes 400 can be made visible from the bottom of footwear 10 by forming openings 310 on bottom side 308d of outsole 300d and bottom side 308e of outsole 300e, and tubes 400 are not visible when they are concealed under outsole 300d and outsole 300e. In some embodiments, openings 310 may be covered by transparent windows. Openings 310 can have various shapes and may be disposed on forefoot portion 12, midfoot portion 14, and/or heel portion 16, depending on which tubes 400 are to be made visible. For example, in outsole 300d of FIG. 4, opening 310a has a trapezoidal shape and is disposed on heel portion 16 to expose a portion of tubes 400 in heel portion 16, and opening 310b is a curve disposed on forefoot portion 12 to expose a portion of tubes 400 in forefoot portion 12. Outsole 300e shown in FIG. 5 only has openings 310c in irregular shapes disposed on forefoot portion 12 to expose a portion of tubes 400 in forefoot portion 12.

[0060]FIGS. 1-5 have shown examples of footwear including tubes 400 having various placements and degrees of visibility. In order to tailor the overall support, cushioning, energy return, and feel of the sole, the placement of tubes 400 can be varied, as discussed above. Also, the characteristics of tubes 400 themselves can be varied. FIGS. 6A-6M provide examples of tubes 400 having different characteristics, by which they provide different degrees of support, cushioning, energy return, and feel. A sole may include all of one type of tube 400, or it can include varying types in order to tailor the overall support, cushioning, energy return, and feel profile of the sole as desired. For example, tubes 400 positioned in a heel portion of a sole may be of a type that provides greater support and energy return at the heel, while tubes 400 positioned in a forefoot portion of that same sole may be of a type that provides lesser support and energy return at the forefoot, to suit the needs and expected use case of the shoe overall.

[0061]A shoe designer may choose to tailor support in this way by using tubes 400 of differing material, size, placement, or—as will be discussed with reference to FIGS. 6A-6M—by using tubes 400 of differing structural characteristics. This range of options, expanded greatly by the inclusion of tubes of different structural characteristics, allows a shoe designer a wide range of design freedom, including both in the performance characteristics and the appearance of their shoes.

[0062]FIGS. 6A-6M show tubes 400 according to various embodiments. These tubes can be incorporated into any shoe sole (e.g., the soles shown in FIGS. 1-5), and in any number, position, or combination as desired by a shoe designer. For ease of reference in description however, FIGS. 6A-6M primarily show tubes 400 with a single tube 400 or a group of four tubes 400 in isolation (i.e., separately from incorporation within a sole). As shown in FIG. 6A, tubes 400a can each have a tubular body 402a with a hollow space 404a defined therein. The opening ends of tubular body 402a can include flanges 403a, which are thicker rims around the opening ends of tubular body 402a to assist assembly. In some embodiments, flanges 403a may be flush with sidewall 204 of midsole 200 and/or sidewall 304 of outsole 300 and visible from the outside of footwear 10. In some embodiments, flanges 403a may protrude beyond sidewall 204 of midsole 200 and/or sidewall 304 of outsole 300 and visible from the outside of footwear 10. In some embodiments, flanges 403a may be fully encapsulated within midsole 200 and/or outsole 300, so that they are not visible.

[0063]In some embodiments, tubular body 402a can be straight and not curved. In some embodiments, tubular body 402a can have a circular cross-section. FIG. 6C is a cross sectional view of tubes 400a along line 6C-6C in FIG. 6A. As shown, tubes 400a can have tubular body 402a with an inner diameter ID and wall thickness t. The sum of inner diameter ID and two times of wall thickness t is an outer diameter OD of tubes 400a. In some embodiments, inner diameter ID can be in a range of 5 mm to 25 mm, such as 10 mm to 20 mm, or 12 mm to 18 mm. In some embodiments, wall thickness t can be in a range of 1 mm to 5 mm, such as 2 mm to 4 mm, or 2.5 mm. While each of tubes 400a is shown to have the same inner diameter ID and wall thickness t, in some embodiments, inner diameter ID and wall thickness t can vary in each tube along the longitudinal direction from heel portion 16 to forefoot portion 12. For example, tubes disposed in heel portion 16 can have the largest wall thickness t, and wall thickness t decreases towards forefoot portion 12. Tubes 400a can also be spaced apart along the longitudinal direction from heel portion 16 to forefoot portion 12 by a distance d. Distance d should be large enough to allow the deformation of tubes 400a when compressed.

[0064]In some embodiments, tubes 400 can have varying lengths L to accommodate the shape of footwear 10. For example, tubes 400a and tubes 400b shown in FIGS. 6A and 6B are configured for a heel portion 16, and therefore the first and the last tube are shorter than the middle tubes to resemble the shape of a heel. Alternatively, tubes 400 may be configured for a forefoot portion 12 and/or a midfoot portion 14, and the length of each tube may vary to accommodate the shape of forefoot or midfoot accordingly.

[0065]Also in some embodiments, the flanges 403 on the ends of tubes 400 are angled at different planes to accommodate the curvature of footwear 10 at sidewall 204 of midsole 200 and/or sidewall 304 of outsole 300. For example, in tubes 400a and tubes 400b of FIGS. 6A and 6B configured for a heel portion 16, flanges 403 of different tubes are not at the same vertical plane. Instead, the vertical plane of flange 403 of the first tube is angled slightly to the front, and the vertical plane of flange 403 of the last tube is angled slightly to the back, so that flanges 403 of all four tubes can together track the curvature of the shape of a heel.

[0066]In some embodiments, as shown in FIG. 6B, tubes 400b can be formed as a unitary cartridge connected by connecting members 406. Connecting a number of tubes (e.g., four tubes) together can help with more efficient manufacturing and positioning of tubes 400b within midsole 200 and/or outsole 300. Connecting members 406 can also have a positioning tab 408 to help aligning tubes 400 with midsole 200 and/or outsole 300. For example, for tubes 400b configured for a heel portion 16 as shown in FIG. 6B, positioning tab 408 can extend over and contact the back of midsole 200 to ensure that tubes 400B do not move relative to midsole 200.

[0067]In some embodiments, tube 400c as shown in FIG. 6D can have a tubular body 402c defining a hollow space 404c and having a constant wall thickness t. In some other embodiments, tube 400d as shown in FIG. 6E can have tubular body 402d defining a hollow space 404d and have varying wall thickness. The varying wall thickness can increase towards the ends of tubular body 402d. For example, the middle of tubular body 402d can have a thickness t1 that is the thinnest, and tubular body 402d becomes thicker towards each end with a thickness t2 larger than thickness t1. Having the ends thicker than the middle allows in the middle of tubular body 402d to be less stiff and provide more cushioning. In some embodiments, tube 400d can be manufactured by an additive manufacturing process.

[0068]In some embodiments, as shown in tube 400d of FIG. 6E, when wall of tubular body 402d becomes thicker towards each end, only an inner diameter ID of hollow space 404d decreases, and the outer diameter of tubular body 402d is constant, so that tubular body 402d on the outside remains straight. For example, at the midpoint of tubular body 402d where it has a wall thickness t1, it has an inner diameter ID1, and at an end of tubular body 402d wall thickness t2 is increased inwardly in hollow space 404d, resulting in a decreased inner diameter ID2. In some embodiments, as shown in tube 400e of FIG. 6F, when wall thickness of tubular body 402e increases from t1 at the midpoint to t2 at each end, inner diameter ID of hollow space 404e remains constant, but the outer diameter of tubular body 402e increases, so that tubular body 402e on the outside has a flared shape towards the ends. In some embodiments, as shown in tube 400f of FIG. 6G, tubular body 402f also has a flared shape towards the ends, as inner diameter increases from ID1 at the midpoint to ID2 at each end, but its wall thickness t remains constant, and instead the outer diameter increases as the inner diameter increases.

[0069]In some embodiments, the varying wall thickness can decrease towards the ends of the tubular body. For example, shown in tube 400g of FIG. 6H, tubular body 402g has wall thickness t2 at the midpoint, and wall thickness decreases to t1 at the ends of tubular body 402. In some embodiments, the varying wall thickness can increase from one end of the tubular body to the other end of the tubular body. For example, shown in tube 400h of FIG. 6i, tubular body 402h has wall thickness gradually increasing from a first end to a second end. Wall thickness t1 at the first end is the smallest, and it increases to t2 at the midpoint, and it to t3 at a second end.

[0070]In some embodiments, as shown in FIG. 6J, tubes 400i can have flanges 410 at both ends. Flanges 410 can have a larger profile than flanges 403 shown in FIGS. 6A and 6B. Flanges 410 can help position tubes 400i within midsole 200 and/or outsole 300. When tubes 400i are assembled, flanges 410 can extend out and contact sidewall 204 of midsole 200 and/or sidewall 306 of outsole 300, thereby resisting the movement of tubes 400f within midsole 200 and/or outsole 300. In some other embodiments, as shown in FIG. 6K, tubes 400j can have flared ends 412 at both ends. Flared ends 412 and have similar function as flanges 410 of tubes 400i to help position tubes 400g within midsole 200 and/or outsole 300. Cutouts 202 of midsole 200 and/or cutouts 302 of outsole 300 can have similar shapes as flared ends 412, so that when tubes 400g are seated within cutouts 202 and/or cutouts 302, flared ends 412 can restrict the movement of tubes 400g relative to midsole 200 and/or outsole 300.

[0071]In some embodiments, as shown in FIGS. 6L and 6M, instead of a circular cross-section, tubes 400k can have a tubular body 402k with an oval-shape cross-section. Because an oval-shape cross-section may be more compressed in the direction of its major axis a2 than a circular cross-section, when a force is applied perpendicular to its major axis, the oval-shape cross-section may allow tubular body 402k to return to its original shape faster, thereby providing energy return.

[0072]Sometimes a footstrike does not exert a force on the sole perpendicularly, for example, during walking or running, a footstrike at a heel can apply a force at an oblique angle relative to the sole. Tubes 400k with oval-shape cross-section can be arranged within midsole 200 and/or outsole 300 such that the major axis of the oval-shape cross-section is perpendicular to an expected force (e.g., by a footstrike). In some embodiments, as shown in FIG. 6L, tubes 400k can be disposed in midsole 200k with major axis a2 arranged at angle θ with respect to horizontal axis a1 of midsole 200k. Angle θ can be in a range of 10° to 80°, such as 30° to 60°, such as 45°. Angle θ can be adjusted so that major axis a2 is perpendicular to an expected force that comes from oblique angle relative to midsole 200k, which allows for maximum force absorption and energy return along major axis a2 of the oval-shape cross-section. Cutouts 202k of midsole 200k can also be shaped to correspond to the shape and orientation of tubes 400k.

[0073]In some embodiments, tubes 400 can further include features along their lengths to help fix tubes 400 within midsole 200 and/or outsole 300. For example, as shown in FIG. 6N, tubes 400l can include barbs 416 for insertion into midsole 200 and/or outsole 300. This can help for insertion of tubes 400l that are slid transversely into corresponding cutouts 202 in a midsole 200 and/or cutouts 302 in an outsole 300. Barbs 416 can stick into the material of midsole 200 and/or outsole 300 to inhibit movement of installed tubes 400l therein. Barbs 416 can provide an assembly solution when it is challenging to cement tubes within the midsole according to conventional practice.

[0074]In some embodiments, barbs 416 may be unidirectional, such that they can only be pushed into an opening in one direction (a first direction), and will stick into the material and prevent movement in the opposing direction (a second direction). Such unidirectional barbs can be especially helpful when there is another feature that prevents movement too far in the first direction (e.g., a closed end of the cutouts 202 and/or cutout 302, or a flange on the trailing end of tube 400l that engages sidewall 204 and/or sidewall 304 when tube 400l is fully seated within cutouts 202 and/or cutout 302).

[0075]Alternatively, as shown in FIG. 6O, tubes 400m can include registration protrusions 418 for insertion into midsole 200 and/or outsole 300. Registration protrusions 418 can have a shape of a cylinder, a cone, a cuboid, or any other shapes that can function for insertion into midsole 200 and/or outsole 300. Midsole 200 and/or outsole 300 can have receptacles that correspond registration protrusions 418, so that tubes 400m can be pressed into midsole 200 and/or outsole 300. This can help for insertion of tubes into soles that are assembled by two portions coming together over the tubes. E.g., tubes 400m are laid in cavities of a portion of a split midsole, and then are covered by another portion of the split midsole to thereby cover and contain tubes 400m (see, e.g., FIG. 8).

[0076]The assembly of tubes 400 with midsole 200 and/or outsole 300 is now being discussed. In some embodiments, as shown in FIG. 7, midsole 200 is formed as a unitary piece, and cutouts 202 are formed as holes extending in midsole 200 in the transverse direction. Midsole 200 may be formed by molding. Tubes 400 may then be pushed and inserted into cutouts 202 from a medial side or a lateral side, until tubes 400 are at a desired distance from sidewall 204 of midsole 200. For example, tubes 400 can flush with sidewall 204 of midsole 200, recessed from sidewall 204 of midsole 200 at a predetermined distance, or protrudes from sidewall 204 of midsole 200 at a predetermined distance. If tubes 400 are tubes 400a with flanges 403a, they may be pushed until flanges 403a are flush with sidewall 204 of midsole 200.

[0077]FIGS. 8 and 9 show the assembly of tubes 400 within midsole 200 and/or outsole 300 according to different embodiments. With reference to FIG. 8, tubes 400 are shown to be assembled between an upper portion 200′ of midsole 200 and lower portion 200″ of midsole 200. Midsole 200 can be any of midsole 200a, 200b, and 200c described above with respect to FIGS. 1-3. Upper portion 200′ can have cutouts 202′, and lower portion 200″ can have cutouts 202″. Cutouts 202′ and cutouts 202″ can together form a stable physical structure for accommodating tubes 400. For example, each of cutout 202′ can have a semi-circular cross-section, and each of cutout 202″ can also have a semi-circular cross-section, such that when upper portion 200′ and lower portion 200″ are stacked together (e.g., by adhesive, welding, or further molding.), they form circular cross-sections to encapsulate tubes 400.

[0078]In the embodiments where tubes 400 have flanges 410, flanges 410 may extend out of cutouts 202′ and cutouts 202′ and contact sidewall 204′ of upper portion 200′ and side wall 204″ of lower portion 200″. In the embodiments where tubes 400 have oval-shaped cross-section (e.g., FIG. 6K), or where tube 400 are curved (e.g., FIG. 6I), cutouts 202′ and cutouts 202″ can be similarly shaped to accommodate tubes 400.

[0079]Additionally, in some embodiments, cutouts 202′ and cutouts 202″ can further include spaces to accommodate connecting members 406 of tubes 400b (e.g., FIG. 6B), flared ends 412 of tubes 400g (e.g., FIG. 6H), and registration protrusions 418 of tube 400i (e.g., FIG. 6O).

[0080]In some embodiments, cutouts 202′ and cutouts 202″ can extend the full width of midsole 200 from the lateral side to the medial side as shown in FIGS. 8 and 9, such that the ends of tubes 400 are exposed from sidewalls 204′ and 204″. In this case, each of tubes 400 can extend the full width of midsole 200 from the lateral side to the medial side. In some other embodiments, cutouts 202′ and cutouts 202″ can only extend a portion of the width of midsole 200 and remain a distance from the lateral side and the medial side, such that tubes 400 are fully encapsulated within the space created by cutouts 202′ and cutouts 202″ and no ends of tubes 400 are exposed from the side. In this case, each of tubes 400 can be less than the width of footwear 10. In some embodiments, cutouts 202′ and cutouts 202″ are open on only a lateral side or a medial side of midsole 200 and extends a portion of the width of midsole, so that they are not open on the other side of midsole 200. In some embodiments, each of cutouts 202′ and cutouts 202″ can extend a different distance from in midsole 200.

[0081]In some embodiments, a single tube 400 can extend across the width of footwear 10 and sit in one of the spaces formed by cutouts 202′ and 202″, as shown in FIG. 8. In other embodiments, as shown in FIG. 9, a single tube 400 can be divided into smaller tubes 420, which are distributed across the width of footwear 10 and in one of the spaces formed by cutouts 202′ and 202″. Smaller tubes 420 can be evenly distributed across the width of footwear 10, or alternatively, smaller tubes 420 can be more concentrated in the center of footwear 10 to provide enhanced cushioning where more pressure is expected.

[0082]While FIGS. 8 and 9 are shown with four tubes 400, and cutouts 202′ and 202″ are arranged in heel portion 16 of footwear 10, it is understood any number of tubes 400 can be used according to the disclosure, and tubes 400 can be arranged in any location of footwear 10 in addition to heel portion 16, such as forefoot portion 12, midfoot portion 14, or a combination thereof. Midsole 200 can be any of midsole 200a, 200b, and 200c described above with respect to FIGS. 1-3, with different numbers of tubes 400 and/or different placements of tubes 400.

[0083]In some embodiments, upper portion 200′, lower portion 200″, and cutouts 202′ and 202″ are formed separately, for example by molding, and tubes 400 are cemented in cutouts 202′ and 202″. Tubes 400 can be cemented in cutouts 202′ and 202″ with or without an adhesive. Tubes 400 can also be secured within cutouts 202′ and 202″ by pressing barbs 416 (e.g., FIG. 6M) or registration protrusions 418 (e.g., FIG. 6N) into cutouts 202′ and 202″. Afterwards, upper portion 200′ and lower portion 200″ can be bonded together to form midsole 200. Upper portion 200′ and lower portion 200″ may be bonded by adhesive, welding, or further molding.

[0084]In some other embodiments, tubes 400 can be directly molded within upper portion 200′ and lower portion 200″, such that cutouts 202′ and 202″ are formed during the molding process. For example, before molding, tubes 400 can be placed between a pre-molded pieces for upper portion 200′ and a pre-molded pieces for lower portion 200″, and after molding, upper portion 200′ and lower portion 200″ form midsole 200 with tubes 400 encapsulated within.

[0085]FIG. 9 shows the embodiments where tubes 400 are assembled between midsole 200 and outsole 300. In such cases, upper portion 200′ as described above can instead be the entirety of midsole 200, and lower portion 200″ as described above can instead be outsole 300, where cutouts 202′ would instead be cutouts 202 and cutouts 202″ would instead be cutouts 302. Midsole 200 can be any of midsole 200a, 200b, and 200c described above with respect to FIGS. 1-3. Outsole 300 can be any of outsole 300a, 300b, 300c, 300d, and 300e described above with respect to FIGS. 1-5.

[0086]FIG. 10 shows another embodiment of the assembly of tubes 400 within a midsole 200d. Midsole 200d is a unitary structure having a first half 210 and second half 212. First half 210 and second half 212 can be divided by a hinge 208 disposed approximate to a middle of midsole 200. And through hinge 208, second half 212 can be divided into an upper portion 212′ and a lower portion 212″. Upper portion 212′ and lower portion 212″ can have cutouts 202′ and 202″ as described above with reference to FIGS. 8 and 9, and tubes 400 can be encapsulated within the spaces formed by cutouts 202′ and 202″ when assembled. Hinge 208 allows either upper portion 212′ or lower portion 212″ to be bent to expose cutouts 202′ and 202″ and allow assembly of tubes 400.

[0087]For example, as shown in FIG. 10, upper portion 212′ of second half 212 can be bent away from lower portion 212″ of second half 212 to expose cutouts 202′ and 202′ and allow placement of tubes 400 into cutouts 202″. Upper portion 212′ can then be closed to sandwich tubes 400 between lower portion 212″. Depending on the location where tubes 400 disposed, second half 212 that is divided to upper and lower portions can be either the forefoot portion or the heel portion, and the location of hinge 208 can be moved closer to the forefoot portion or closer to the heel portion.

[0088]In some other embodiments, instead of upper portion 212′, lower portion 212″ can be bent away from upper portion 212′ to expose cutouts 202′ and 202″ and allow placement of tubes 400 into cutouts 202′. Lower portion 212″ can then be closed to sandwich tubes 400 between upper portion 212′ and lower portion 212″.

[0089]FIG. 11 illustrates embodiments where negative spaces 602 are used instead of tubes 400 to provide rebounding and cushioning effect. A midsole 600 for footwear 10 is shown with negative spaces 602 extending through the width of midsole 600. In some embodiments, negative spaces 602 extend only a portion of the width of midsole 600. Negative spaces 602 can have a tubular shape with circular cross-section, therefore resembling the shape of tubes 400 described above.

[0090]Negative spaces 602 can also have alternative structures similar to tubes 400 described above. For example, in some embodiments, negative spaces 602 can have varying lengths to accommodate the varying width of midsole 600. In some embodiments, negative spaces 602 may curve downwardly within midsole 600. In some embodiments, negative spaces 602 may have oval-shape cross-section instead of circular cross-section. In some embodiments, inner diameter ID of negative spaces 602 can vary along the width of midsole 600, such that inner diameter ID is the largest at the middle and decreases towards the ends of negative spaces 602. In some alternative embodiments, inner diameter ID of negative spaces 602 can vary in the reverse direction, such that inner diameter ID is the smallest at the middle and increases towards the ends of negative spaces 602. In some embodiments, inner diameter ID of negative spaces 602 can increase from the medial side to the lateral side, or increase from the lateral side to the medial side.

[0091]The placement of negative spaces 602 is also similar to tubes 400 described above. Any number of negative spaces 602 can be disposed throughout midsole 600, for example, in heel portion 16, forefoot portion 12, midfoot portion 14, or any combination thereof. Negative spaces 602 can be evenly distributed or more concentrated to tailor the cushioning effect is desired.

[0092]Midsole 600 can be a foam structure molded from a thermoplastic polymer (such as EVA, TPU, PU, PEBA, or TPEE). In some embodiments, negative spaces 602 can be integrally formed during the foam molding process, and in some other embodiments, negative spaces 602 can be drilled or cut from midsole 600 after midsole 600 is molded into shape.

[0093]In some embodiments, the inner surface 604 of negative spaces 602 can be thermally treated to provide a hardened finish. For example, a heated rod can be inserted into negative spaces 602 to roll over inner surface 604 to heat inner surface 604. Thermally treated inner surface 604 can have a larger hardness, which further resembles tubes 400 having a hardness more than the surrounding midsole. Hardened inner surface 604 can resist compression of midsole 600 beyond the compression of negative spaces 602, and can allow negative spaces 602 to return to their original shape after being deformed faster than midsole 600, thereby providing both cushioning and rebounding effect in a similar manner as tubes 400 discussed above.

[0094]Another aspect of the disclosure includes a structure to expose a portion of tubes 400 or negative spaces 602 as a visual cue of the function of the energy return system. In some embodiments, as shown in FIG. 12, a transparent shell 508 covers the perimeter of midsole 200, so that sidewall 204 and tubes 400 are visible through shell 508. Shell 508 can be formed of a material that is transparent. For example, shell 508 can be formed of transparent TPEE, TPU, EVA, or PU. In some embodiments, tubes 400 can have a vibrant color, such as red, to achieve a more apparent visual cue. In some embodiments, outsole 300 can also include a transparent material or openings 310 to expose tubes 400 from the bottom of footwear 10.

[0095]In some embodiments, as shown in FIG. 13, tubes 400 can be arranged on a window tray 502, which is embedded in midsole 200. Window tray 502, similar to shell 508, may be formed of a material that is transparent. For example, window tray 502 can be formed of transparent TPEE, TPU, EVA, or PU. Window tray 502 can include a side panel 504 that to expose tubes 400 from side of midsole 200 and a bottom panel 506 to expose tubes 400 from the bottom of midsole 200. In some embodiments, to further expose tubes 400 from the bottom of outsole 300, outsole 300 can include opening 310 in the location overlaying bottom panel 506.

[0096]In embodiments where negative spaces 602 are used in lieu of tubes 400, midsole 600 can similarly include shell 508 that is transparent, as shown in FIG. 14. Shell 508 can be formed of a material that is transparent, and negative spaces 602 can be visible from the outside of shell 508. In some embodiments, shell 508 can include protrusions 514 that can mate with negative spaces 602 to help secure midsole 600 in position relative to shell 508. Protrusions 514 can also be transparent. In some other embodiments, shell 508 can include openings 510 aligning with negative spaces 602, so that negative spaces 602 are exposed through openings 510, as shown in FIG. 15.

[0097]In some embodiments, midsole 600 can have a vibrant color, such as red, to achieve a more apparent visual cue. In some embodiments, negative spaces 602 can have a different color than the rest of midsole 600. For example, inner surface 604 of negative spaces 602 can have a contrasting color to the rest of midsole 600 to signal to a consumer the energy return function of negative spaces 602. The different color of negative spaces 602 can be achieved by the preform material selected for negative spaces 602 or by treatment of inner surface 604 after negative spaces 602 are molded.

[0098]When negative spaces 602 are created in midsole 600, the structure of negative spaces 602 can only be shown through sidewall 606 of midsole 600, but it cannot be shown from a bottom 608 of midsole 600. To solve this problem, in some embodiments, bottom 608 of midsole 600 can be molded to a shape that mimics the tubular shape of negative spaces 602. For example, as shown in FIG. 15, bottom 608 of midsole 600 can be shaped to have tubular shapes 618 representing the location of negative spaces 602 extending inside midsole 600. In some embodiments, outsole 300 has cutout 303 overlaying carved out tubular shapes 618, so that they are exposed through outsole 300.

[0099]It is to be appreciated that the Detailed Description section, and not the Summary and Abstract sections, is intended to be used to interpret the claims. The Summary and Abstract sections may set forth one or more but not all exemplary embodiments of the present disclosure as contemplated by the inventor(s), and thus, are not intended to limit the present disclosure and the appended claims in any way.

[0100]The foregoing description of the specific embodiments will so fully reveal the general nature of the disclosure that others can, by applying knowledge within the skill of the art, readily modify and/or adapt for various applications such specific embodiments, without undue experimentation, without departing from the general concept of the present disclosure. Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance.

[0101]The breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the claims and their equivalents.

[0102]The claims in the instant application are different than those of the parent application or other related applications. The Applicant therefore rescinds any disclaimer of claim scope made in the parent application or any predecessor application in relation to the instant application. The Examiner is therefore advised that any such previous disclaimer and the cited references that it was made to avoid, may need to be revisited. Further, the Examiner is also reminded that any disclaimer made in the instant application should not be read into or against the parent application.