The invention relates generally to impact-attenuation systems, e.g. for use in footwear and other foot-receiving devices, such as in the heel areas of footwear or foot-receiving device products, and particularly to athletic shoes having shock-absorbing soles for use with rigorous activities such as running or court sports.
The present invention relates to shoes. The present invention offers several practical applications in the technical arts, including but not limited to the use of shock-absorbing soles in shoes. More particularly, the present invention relates to the shock-absorbing characteristics of sole portions of shoes.
Conventional articles of athletic footwear have included two primary elements, namely an upper member and a sole structure. The upper member provides a covering for the foot that securely receives and positions the foot with respect to the sole structure. In addition, the upper member may have a configuration that protects the foot and provides ventilation, thereby cooling the foot and removing perspiration. The sole structure generally is secured to a lower portion of the upper member and generally is positioned between the foot and the ground. In addition to attenuating ground or other contact surface reaction forces, the sole structure may provide traction and control foot motions, such as pronation or suppination. Accordingly, the upper member and sole structure may operate cooperatively to provide a comfortable structure that is suited for a variety of ambulatory activities, such as walking, running or playing basketball.
A conventional athletic shoe includes an outsole, a midsole, and an upper. Such a shoe is typically designed to reduce the shock felt by the wearer during foot strike(s). Such reduction in shock may provide comfort and reduce the likelihood of injury to the wearer. Unstable shoes may cause short- or long-term injury due to the excessive motion at the joints brought on by unstable materials and designs.
Cushioning in most athletic shoes is supplied through a foam midsole made from ethylene vinyl acetate (EVA) or polyurethane (PU). These materials are relatively inexpensive, easily molded, and provide ample cushioning when they are new. Other shoes have used gas-filled and liquid-filled bladders to provide the required cushioning. Both of these shoe constructions provide adequate cushioning when they are new. Fluid-filled bladders continue to provide like-new cushioning for the life of the shoe, assuming that the fluid remains encapsulated in the shoe. In contrast, shoe midsoles made from foams provide adequate cushioning when they are new, but quickly lose some of their cushioning ability when the open cellular structure inside the foam suffer catastrophic failure from the application of vertical and/or shear forces. EVA foams have compression (compaction) set rates of greater than 50%. This means that the ability to provide cushioning is reduced by at least 50% due to compaction of the cushioning material. In contrast to EVA, PU generally has better compression set. However, the use of PU increases the weight of the shoe compared to the use of EVA.
In addition to cushioning, a shoe should also supply support and stability. Generally, as the materials used under foot become softer, the support and stability decrease. Harder/firmer materials lend the most support and stability. Since harder/firmer materials decrease the amount of available cushioning, providing adequate cushioning without detracting from support and stability may be a challenge that requires attention to detail with respect to material choices and design.
Aspects of this invention relate to impact-attenuation systems, e.g., for use in footwear and other foot-receiving devices, such as in the heel areas of footwear or foot-receiving device products, and/or to the provision of an improved shoe, such as a light-weight shoe having a sole that provides excellent shock absorption without reducing support and stability.
A shoe of the present invention may have a sole for supporting a foot of a wearer, and a shoe upper adjacent to the sole. The sole may comprise an upper force-distribution plate portion, a lower force-distribution plate portion spaced below the upper force-distribution plate portion, a lateral shell connecting the upper and lower force-distribution plate portions, and at least one resilient shock-absorber element in contact with and between both the upper and lower force-distribution plate portions.
In another aspect of the present invention, a shoe comprises a sole for supporting a foot of a wearer, and a shoe upper adjacent the sole. A sole may comprise an outsole portion spaced below the upper and a plurality of discrete, resilient, shock-absorber elements. Shock-absorber elements may be positioned between the outsole portion and the upper. Each shock-absorber element may be generally circular in shape in horizontal cross-section. In embodiments, a plurality of shock-absorber elements are aligned along a heel shank of the sole.
Other objects and features will be in part apparent and in part pointed out hereinafter.
A more complete understanding of the present invention and certain advantages thereof may be acquired by referring to the following description in consideration with the accompanying drawings, in which like reference numbers indicate like features.
In the following description of various example embodiments of the invention, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration various example devices, systems, and environments in which aspects of the invention may be practiced. It is to be understood that other specific arrangements of parts, example devices, systems, and environments may be utilized and structural and functional modifications may be made without departing from the scope of the present invention. Also, while the terms “top,” “bottom,” “side,” “front,” “rear,” “upper,” “lower,” “vertical,” “horizontal,” and the like may be used in this specification to describe various example features and elements of the invention, these terms are used herein as a matter of convenience, e.g., based on the example orientations shown in the figures, orientations at rest, and/or orientations during typical use. This specification should not be construed as requiring a specific three dimensional orientation of structures in order to fall within the scope of this invention.
To assist the reader, this specification is broken into various subsections, as follows: Terms; General Background Relating to the Invention; General Description of Impact-Attenuation or Shock-Absorbing Systems and Products Containing Them; Example Foot-Receiving Device Configurations; and Conclusion.
A. Terms
The following terms are used in this specification, and unless otherwise noted or clear from the context, these terms have the meanings provided below.
“Foot-receiving device” means any device into which a user places at least some portion of his or her foot. In addition to all types of footwear (described below), foot-receiving devices include, but are not limited to: bindings and other devices for securing feet in snow skis, cross country skis, water skis, snowboards, and the like; bindings, clips, or other devices for securing feet in pedals for use with bicycles, exercise equipment, and the like; bindings, clips, or other devices for receiving feet during play of video games or other games; and the like.
“Footwear” means any type of wearing apparel for the feet, and this term includes, but is not limited to: all types of shoes, boots, sneakers, sandals, thongs, flip-flops, mules, scuffs, slippers, sport-specific shoes (such as golf shoes, basketball shoes, tennis shoes, baseball cleats, soccer or football cleats, ski boots, etc.), and the like.
“Foot-covering members” include one or more portions of a foot-receiving device that extend at least partially over and/or at least partially cover at least some portion of the wearer's foot, e.g., so as to assist in holding the foot-receiving device on and/or in place with respect to the wearer's foot. “Foot-covering members” include, but are not limited to, upper members of the type provided in some conventional footwear products.
“Foot-supporting members” include one or more portions of a foot-receiving device that extend at least partially beneath at least some portion of the wearer's foot, e.g., so as to assist in supporting the foot and/or attenuating the reaction forces to which the wearer's foot would be exposed, for example, when stepping down in the foot-receiving device. “Foot-supporting members” include, but are not limited to, sole members of the type provided in some conventional footwear products. Such sole members may include conventional outsole, midsole, and/or insole members.
“Contact surface-contacting elements” or “members” include at least some portions of a foot-receiving device structure that contact the ground or any other surface in use, and/or at least some portions of a foot-receiving device structure that engage another element or structure in use. Such “contact surface-contacting elements” may include, for example, but are not limited to, outsole elements provided in some conventional footwear products. “Contact surface-contacting elements” in at least some example structures may be made of suitable and conventional materials to provide long wear, traction, and protect the foot and/or to prevent the remainder of the foot-receiving device structure from wear effects, e.g., when contacting the ground or other surface in use.
B. General Background Relating to the Invention
In producing athletic footwear, manufacturers generally tend to restrict movement of a wearer of the footwear as little as possible. However, due to the different loads that arise on bones and muscles during ambulatory activities, footwear may also be designed to reduce fatigue and/or the risk of injuries under applied incident loads. One cause of injuries and/or premature fatigue of joints and/or muscles during exercise relates to the misorientation of the foot during a step cycle. During a normal step walking, the average person tends to first contact the ground with the heel and subsequently rolls-off off the heel using the ball of the foot.
Many people slightly turn their foot from the outside to the inside between the first ground contact with the heel and pushing-off with the ball of the foot. At ground contact, a person's center of mass typically is located more on the lateral side (the outside) of the foot, but it tends to shift to the medial side (the inside) during the course of the step cycle. This turning of the foot to the medial side is called “pronation.” “Supination,” on the other hand, constitutes a turning of the foot in the opposite direction during the course of a step. Supination and excessive pronation can lead to increased strain on the joints and premature fatigue or even injury. Therefore, manufacturers of shoes, and particularly athletic shoes, make efforts to control the degree of turning of the foot during a step cycle in order to avoid these misorientations.
There are a number of known ways of influencing pronation. For example, supporting elements often are placed in the midfoot and/or forefoot areas of a sole structure to help users avoid excessive turning of the foot to the medial and/or lateral sides, e.g., during push-off. Typically, the heel portion of such sole structures only serves to attenuate ground reaction forces. Such corrective measures, however, fail to recognize that the initial ground contact phase of a step cycle also influences the later course of motion of the foot during the step.
At least some aspects of the present invention relate to providing foot-supporting structures for articles of footwear and other foot-receiving device products that help provide improved and/or correct orientation of a foot starting from the first ground contact phase of a step cycle. Such improvements and/or corrections may help reduce and/or eliminate misorienations, premature fatigue, and/or wear of the joints and the muscles.
C. General Description of Impact-Attenuation or Shock-Absorbing Systems and Products Containing them
In general, aspects of this invention relate to impact-attenuation or shock-absorbing members, products and systems in which they are used (such as footwear, other foot-receiving devices, heel cage elements, and the like), and methods for including them in such products and systems and using them in such products and systems. These and other aspects and features of the invention are described in more detail below.
1. Foot-Receiving Device Products Including Impact-Attenuation Members According to the Invention
Foot-receiving device products, such as articles of footwear, in accordance with at least some example aspects of this invention, comprise: (a) a foot-covering member, such as an upper member for an article of footwear; and (b) a foot-supporting member (such as a sole structure) engaged with the foot-covering member. The foot-supporting member (e.g., sole structure) may include impact-attenuating or shock-absorbing members located in a heel portion of the foot-supporting member in various configurations. Impact-attenuating members may be provided in the sole structure in different configurations without departing from the invention. For example, in some structures according to the invention, an impact-attenuating member may be provided: (a) in the lateral heel portion of the sole structure in front of a softer and/or less impact force-resistant impact-attenuating member; (b) in the medial heel portion of the sole structure in front of a softer and/or less impact force-resistant impact-attenuating member; (c) in the rear, medial heel portion (e.g., along a side of a softer and/or less impact force-resistant impact-attenuating member); (d) along an arch portion; and/or (e) in a forefoot portion. In at least some example foot-receiving device structures in accordance with embodiments of the present invention, some or all of impact-attenuation member(s) of a shock-absorbing system may be included at locations and orientations so as to be at least partially visible from an exterior of an article of footwear. Alternatively, if desired, impact-attenuation member(s) may be hidden or at least partially hidden in the overall footwear or foot-receiving device product structure, such as within the foam material of a midsole element, within a gas-filled bladder member, etc. For example, impact-attenuation member(s) may be placed within a heel region, a forefoot region, and/or within a full region under the sole of a shoe.
Additional aspects of this invention relate to foot-supporting members and/or impact-attenuation systems, e.g., sole structures or portions thereof, such as a heel unit or the like, that include two or more impact-attenuating members, e.g., of the various types, constructions, orientations, and/or relative characteristics described above. If desired, the various impact-attenuating members may be engaged with a common base member, e.g., to provide a structure that is insertable as a unit into an article of footwear or other foot-receiving device constructions. Such members and/or systems may have relative orientation and/or impact-attenuating characteristics described above.
2. Methods of Making and Using Foot-Receiving Device Products According to the Invention
Additional aspects of this invention relate to methods of making footwear or other foot-receiving device products including impact-attenuation members or shock-absorbing elements structured and/or arranged in accordance with examples of this invention and methods of using such impact-attenuation members and/or such products, e.g., for attenuating contact surface reaction forces. Such methods may include: (a) providing a foot-covering member, such as an upper member for an article of footwear (e.g., by making it in a conventional manner, obtaining it from another source, etc.); and (b) engaging a foot-supporting member (e.g., a sole structure) with a foot-covering member.
Once a shock-absorbing system and/or impact-attenuation member(s) have been incorporated in an article of footwear or other foot-receiving device product structure, the article of footwear or other product may be used in a known manner, and the impact-attenuation members may attenuate the ground reaction forces (e.g., as a result of landing a step or jump). In examples, an article of footwear may constitute an athletic and/or training shoe, e.g., used for running, walking, basketball, other ambulatory and/or athletic activities, etc.
D. Example Foot-Receiving Device Configurations
The various figures in this application illustrate examples of impact-attenuation members and/or shock-absorbing elements and shock-absorbing systems, as well as products and methods according to examples of this invention. When the same reference number appears in more than one drawing, that reference number may be used consistently in this specification and the drawings to refer to the same or similar parts throughout. In the description above and that which follows, various connections and/or engagements are set forth between elements in the overall structures. The reader may understand that these connections and/or engagements are general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect.
In embodiments, shock-absorber elements 144 may be connected to one or more resilient integral plate portion(s) 147 that connect the shock-absorber elements 144, or sub-groups thereof, to form shock-absorber units. Shock-absorber elements 144 may be formed on resilient integral plate portion 147 as raised balls extending therefrom. For instance, shock-absorber elements 144 may be molded as an integral unit along with, and from the same material as, resilient integral plate portion 147. Resilient integral plate portion 147 may be in contact with upper force-distribution plate portion 146 and, further, may transfer forces therefrom to shock-absorber elements 144. In alternative embodiments, shock-absorber elements 144 may be directly connected to upper force-distribution plate portion 146.
Upper force-distribution plate portion 146 and/or lower force-distribution plate portion 148 may possess a characteristic of being semi-rigid. A semi-rigid characteristic may provide load distribution and stability to shock-absorbing support system 140. Shock-absorber elements 144 may be in contact with and extend between force-distribution plate portion(s) 146 and/or 148. Additionally, shock-absorber elements 144 may provide shock attenuation and cushioning. Further, lateral shell 142 may enhance support and stability of a system by providing a lateral structure that can generally encapsulate the system and/or assist with retaining its shape and orientation during use.
Force-distribution plate portion(s) 146 and/or 148 may form upper and lower perimeters, respectively, of shock-absorbing support system 140. Additionally, force-distribution plate portion(s) 146 and/or 148 may be sufficiently stiff to provide stability and to transfer the loading forces of a foot to shock-absorber elements 144. In embodiments, upper force-distribution plate portion 146 may be sufficiently stiff to prevent the user from feeling individual shock-absorber elements 144. In further embodiments, upper force-distribution plate portion 146 may be formed of relatively rigid material, such as nylon. Additionally and/or Alternatively, upper force-distribution plate portion 146 may be molded into or otherwise adhered to midsole 124. Additionally, upper force-distribution plate portion 146 may comprise a thin midsole and a lasted upper. In embodiments, shock-absorber elements may be aligned beneath a thin midsole adhered to an upper, where the thin midsole and upper may act as an upper force-distribution plate portion 146. In further embodiments, lower force-distribution plate portion 148 may comprise a lower portion of lateral shell 142.
Shock-absorber elements 144 may accept shock as transferred from force-distribution plate portion(s) 146 and/or 148. Further, shock-absorber elements 144 may deform as a load is applied. Further, shock-absorber elements 144 may provide resistance to an applied load. Additionally, shock-absorber elements 144 may return to their original shape when an applied load is removed. Further, shock-absorber elements 144 may have durometer hardness less than that of force-distribution plate portion(s) 146 and/or 148. In embodiments, a choice of material, hardness, geometry, placement and number of shock-absorber elements may affect a cushioning response of a heel shock-absorbing support system. Highly resilient, elastic, deformable materials that do not take a compression set may be desirable, such as thermoplastic urethane, thermoplastic rubber, polybutadiene, and peebax. Alternatively, shock-absorber elements 144 may comprise gas-filled or fluid-filled containers that provide a desired stiffness and/or resiliency. In further embodiments, shock-absorber elements 144 may be made of PU or EVA.
A rounded geometry of shock-absorber elements 144 may provide various advantages. For example, vertical and/or shear forces applied to shock-absorber elements 144 during use of an athletic shoe may often exceed several times a wearer's body weight. Therefore, the shape of shock-absorber elements, such as shock-absorber elements 144, may be desired to be conducive to resisting these forces. In embodiments, each shock-absorber element 144 may have a generally circular shape through its horizontal cross-section and/or may have a generally ellipsoidal shape. In further embodiments, each shock-absorber element 144 may be generally spherical in shape. Additionally and/or alternatively, a sphere and/or ball-shaped shock-absorber element 144 may effectively and resiliently respond to vertical and shear loading. Rounded and/or generally spherically-shaped shock-absorber elements 144 may generally not bend or kink when loaded. Rather, rounded and/or generally spherically-shaped shock-absorber elements 144 may generally deform under an applied load by flattening until the load is removed, at which time the shock-absorber elements 144 may return to their original shape.
In embodiments, lateral shell 142 is relatively rigid to provide support and stability to shock-absorbing system 140. In the configuration shown, lateral shell 142 is formed as a lateral wall extension of lower plate portion 148. However, lateral shell 142 may be formed independently and may be made from a different material. In embodiments, lateral shell 142 may wrap around the vertical periphery of heel region 132 and connect upper and lower force-distribution plate portions 146 and 148, respectively. As such, lateral shell 142 may generally encapsulate shock-absorber elements 144 and form a border along three sides of the shock-absorbing system 140. Accordingly, lateral shell 142 may provide a firm wall for retaining a desired configuration of a shock-absorbing system 140 during use. In alternative embodiments, an outsole made of a sufficient hardness and thickness may act as the force-distribution plate 148. Further, an outsole made of a sufficient hardness and thickness may wrap up to connect to the upper, acting a lateral shell. In embodiments, sufficient hardness may comprise a hardness that is harder than the hardness of shock-absorber elements used in embodiments of a shoe.
Lateral shell 142 may be made from various materials, such as a suitable polymeric material that may be injection- or compression-molded. Examples may comprise a high hardness thermoplastic urethane (TPU) and/or nylon. More expensive materials such as carbon fiber may also be used to reduce weight but are not necessary to achieve the required mechanical properties. Cost, thermal stability, hardness range, bending resistance and component bonding may all be considered for material selection. In embodiments, lateral shell 142 and the upper and lower force-distribution plate portions 146 and/or 148, respectively, may have a durometer hardness of at least 70 shore D in order to achieve the desired hardness to transfer the load to the shock-absorber elements 144 and retain the desired configuration of shock-absorbing system 140 during use. The hardness of the force-distribution plate portion(s) 146 and/or 148 may be varied to increase or decrease stability and to meet the requirements of the particular sport or activity.
Lateral shell 142 in the configuration shown is a generally C-shaped component and surrounds the heel region 132. However, in alternative configurations, lateral shell 142 may only partially surround heel region 132. Further, lateral shell 142 and lower force-distribution plate portion 148 may be transparent or translucent to permit viewing of shock-absorber elements 144 by a user through the side portions of a heel or through portions of an outsole, such as outsole 122.
Further, the size and number of shock-absorber elements 244 may vary. For instance, shock-absorber elements 244 located along the periphery of the heel region 232 may have larger widths and/or diameters to provide greater resilience and shock-absorbing abilities along the perimeter, and the smaller shock-absorber elements 244 located in a central region can have smaller widths and/or diameters. Generally, shock-absorber elements 244 may have a diameter of about 10 to 23 mm. For example, shock-absorber elements 244 may range in diameter from about 12 to 20 mm depending on factors like type of shoe, shoe size, and location of the shock-absorber element 244 within a shoe, etc.
In particular,
E. Conclusion
The present invention has been described in relation to particular embodiments, which are intended in all respects to be illustrative rather than restrictive. Alternative embodiments will become apparent to those of ordinary skill in the art to which the present invention pertains without departing from its scope.
From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects set forth above, together with other advantages which are obvious and inherent to the system and method. It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of the claims.
This application Claims Benefit To U.S. Provisional Patent Application No. 61/115,027, Filed Nov. 14, 2008, Entitled “Icon Type Midsole Member For Footwear.”
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