Sole Unit for Footwear and Footwear Incorporating Same

Abstract

The present invention discloses a sole unit for shoes, sandals, boots, and other articles of footwear. The sole unit comprises at least one spring unit having at least a top wall and a bottom wall that define an opening to allow the top and bottom walls to converge under force, absorbing energy on impact and releasing energy on rebound. Variations in the longitudinal profile, transverse profile, spring-wall thickness, and spring-wall shape permit control over spring force in response to compression. A spring unit may further comprise one or more dampeners to modify the energy-storing properties of the spring unit. A spring unit may further comprise one or more bumpers that come into contact at predetermined distances when compressing the spring unit, to further modify the dynamic response of the spring under a load.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application Nos. 60/609,937, filed Sep. 14, 2004 by Alan Hardy and Mark McMillan, and 60/610,302, filed Sep. 15, 2004 by Alan Hardy and Mark McMillan the disclosures of which are hereby incorporated by reference as if listed in their entirety.

BACKGROUND OF THE INVENTION

[0002] The natural motions of the human foot during a foot strike (step) are complex and multidirectional, especially during sporting activities. Traditional footwear materials are generally very basic and cannot respond and react against these forces in a manner that compliments the natural variations in force and transitions of foot motion other than in a very linear and uniform way. Each sport and sporting activity has specific characteristics in terms of foot strike (stepping motions) and force transitions. Traditional cushioning elements are used in very similar ways for each sport, and therefore are only generally adaptable to the specific needs of each sport. Traditional cushioning materials offer a very similar effect to stepping onto a flat, cushioned floor surface with the disadvantage of exaggerated and unnatural torsional traction with the ground and occasionally unforgiving structural support from the footwear upper. Quite often, the consequence is less-than-optimal transitional results, greater instability, and higher likelihood of injury.

[0003] Footwear cushioning materials often offer only underfoot protection against basic linear impact shock, not against the rotational, torsional, and other more-complex dynamic movements related to foot and joint trauma. Therefore many traditional cushioning materials restrict and reduce the natural biomechanical responses from the foot and related joints and adjoining structure.

[0004] During most sports and athletic activities, the foot is subject to diverse and violent forces in terms of impact shock. Vertical, linear, lateral, and rotational (torsional) forces and motion transitions can be unnaturally high. These exaggerated forces can be attributed to advancements in the human condition, advancements of footwear design (traction/support) and technologies, and increasing physical requirements of the evolving sporting activities. The human foot is adaptable and well-suited to these dynamic requirements in terms of the biomechanical nature of the foot and ankle structure, but is somewhat disadvantaged by the more general and unspecific nature of the approaches at protection through footwear design and footwear engineering innovation.

[0005] Cushioning elements of most current sport and athletic footwear include basic shock absorbing and protective underfoot materials, such as foam, gel (visco-elastomers), structure or air springs, together with more traditional applications of upper design, for structure, support, and stability enhancement. Usually a consistent and uniform layer of shock absorbing and protective material, such as EVA or polyurethane foam, is placed between the foot and the ground.

[0006] These elements have limited structural adjustability and variability through design, due to the nature of the materials. Manufacturing limitations inherent in these materials also prove to be not very adaptable in terms of the variety of underfoot movements and kinetic dynamics during stepping or foot-strike motions. These traditional materials generally absorb shock in a spring-like manner, returning much of the energy in an uncontrolled fashion. Undampened or lightly dampened rebound is dissimilar to the natural function of the foot and its structural elements.

[0007] There have been some attempts to improve conventional sole units based on EVA or polyurethane foam, which have been the traditional footwear cushioning materials. In these attempts, polymer spring units have been placed in portions in the sole, particularly the heel portion, and in some cases the forefoot portion. See, for example, U.S. Pat. No. 5,461,800, which is hereby incorporated by reference in its entirety. The U.S. Pat. No. 5,461,800 patent discloses a foamless midsole unit, comprising upper and lower plates sandwiching transverse cylindrical units formed of resilient polymer. This system, as well as others, are based on constant linear geometry and protect the foot only against basic inertia shock, not against rotational, torsional, or other non-linear dynamic movements related to foot and joint trauma. Therefore many prior attempts restrict and reduce the natural biomechanical responses from the foot and related joints and adjoining structure. For example, the prior art typically has spring elements of a constant two-dimensional cross-section from rearfoot to forefoot and from the medial side to the lateral side. See, for example, U.S. Pat. No. 4,910,884, 6,625,905, or 5,337,492. However, these disclosures do not address, and in part restrict, a nonlinear asymmetrical foot strike and subsequent flex-transition from heel to toe.

[0008] There is a tremendous opportunity for improving the current state of general sporting footwear ride and cushioning by approaches catered to these specific requirements; for example, by utilizing a cushioning device that offers a finer level of regionally specific tuning and adaptable transitions for the complex and dynamic forces encountered by the foot, the forces the foot is subjected to, and by the foot's interaction with the ground during a foot strike or stepping action.

SUMMARY OF THE INVENTION

[0009] The present invention is a sole unit for footwear that overcomes problems in the prior art by providing at least one spring unit, dampener, or contact bumper, alone or in combination, for example, as described below:

[0010] A shoe having a sole unit comprising a spring unit, wherein

[0011] the spring unit is adapted for use in footwear and having at least a top wall and a bottom wall;

[0012] an opening disposed between the top and bottom walls to allow the top and bottom walls to converge under force;

[0013] the spring unit comprising a first profile for at least a portion of the top and bottom walls that is generally oriented in a longitudinal axis, and a second profile for at least a portion of the top and bottom walls that is generally oriented along an axis transverse to the longitudinal axis;

[0014] the first profile providing a plurality of spring rates along the longitudinal axis, through varying, complex sectional shape and dimension in order to offer different and appropriate resistances and spring rates throughout the length and width of the unit; and

[0015] the second profile providing a plurality of spring rates along the transverse axis, also through varying, complex sectional shape and dimension.

[0016] A sole unit as described above wherein the first profile generally is converging going from a rearward end of the spring unit toward a frontward end of the spring unit.

[0017] A sole unit as described above wherein the first profile generally is converging going from a frontward end of the spring unit toward a rearward end of the spring unit.

[0018] A sole unit as described above wherein the second profile is generally converging going from a lateral side to a medial side, or medial side to lateral side, but may have multiple convergences in order to offer plurality of spring rates, depending on the directional load requirements.

[0019] A sole unit as described above wherein there are a plurality of sections of convergence or divergence between the lateral and medial sides of the second profile.

[0020] A sole unit as described above wherein between the lateral and medial sides of the second profile there are a plurality of sections of convergence or divergence.

[0021] A sole unit as described above wherein between the front and rear of the spring unit along the longitudinal axis there are a plurality of sections of convergence or divergence.

[0022] A sole unit as described above wherein along the longitudinal axis, there is a change in the uniformity of the top or bottom wall's responsiveness to force due to varying and changing sectional thicknesses throughout the surfaces, creating complex and non-uniform sections throughout the unit, together with different material types, hardnesses, and flexibilities, and with optional laminations and combinations of other shaped surfaces, the spring unit offers a tuned and structured variety of load resistances, and appropriate directional force management, dependent upon the requirements of the various typical foot-strike and load management requirements.

[0023] A sole unit as described above wherein the angles of the front and rear surfaces, combined with the radii at adjoining bottom and top walls can be adjusted to accommodate to different load, load direction, and energy transitional requirements, according to the particular purpose of the shoe.

[0024] A sole unit as described above further comprising one single, or a plurality of spring units, which may be connected or separate and independent, and which are placed in any and various areas of the underfoot, in any and various configurations including angular and diverse alignments which correspond to directional load transference during different foot strikes and transitions, and which are not restricted to any symmetry around any linear longitudinal or medial to lateral axis, in order to provide many different truly bio-mechanically correct and ergonomically appropriate options of foot-strike, force dissipation and complex loading transitions during foot strike, and so catering to different requirements of various users, and purposes of the shoe. For example, FIG. 21 is a diagram illustrating typical load transition lines encountered by a runner and an exemplary placement of spring units relative to the load transition lines. FIG. 22 is a diagram of lines of symmetry for a shoe or foot and spring units in non-symmetrical alignment therewith based on the force transition lines of FIG. 21.

[0025] A sole unit as described above further comprising a dampener which can be co-produced and integral with the unit, directly laminated to, or mechanically fixed to the unit, in part or in whole, in order to offer adaptability in constructions and customizable for particular footwear requirements.

[0026] A sole unit as described above wherein the dampener is associated with at least one surface of the spring unit, so that compression of the spring unit places the dampener under tension, creating a return force applied to the spring unit.

[0027] A sole unit as described above wherein the spring unit is located at a position in the rear lateral area of the heel of the underfoot, or at a position of the foot which makes contact with the ground first, during stepping or foot-strike motion, can have its long surfaces aligned transversely with this axis appropriate to foot-strike patterns typical to linear stepping motion, motion such as while running, or sideways lateral foot strike such as in court sport activity.

[0028] A sole unit as described above wherein the spring unit can be made from any material with spring-like, energy absorbing and energy storing qualities, such as polymers, metals, composites, or any appropriate combinations of these.

[0029] A sole unit as described above wherein the spring unit further comprises at least one bumper to limit travel of opposing walls of the spring unit.

[0030] A sole unit as described above wherein the dampener and the bumper can be designed to be integral and combined in the same element.

[0031] A sole unit comprising at least one spring unit, the spring unit having opposing top and bottom walls, spaced along an axis, the spring unit having a plurality of spring rates along at least a portion of the axis, and a dampener disposed between top and bottom walls.

[0032] A sole unit as described above wherein the dampener is disposed so that the length or elongation of the dampener does not exceed the maximum opening between the surfaces of the spring unit to which it is attached or aligned, thereby coming into tension at the point when the load on the spring unit is released and the forces are returned by the spring unit.

[0033] A sole unit as described above wherein the spring unit has continuous complex curved surfaces, including an upper, outer surface that conforms to the bottom shape of the foot, in the areas where the spring unit is located, together with included sectional thickness and shape alterations throughout its length in order to offer differing and appropriate resistances to loading.

[0034] A sole unit as described above wherein the spring unit has an upper, outer surface that conforms to the bottom shape of the foot includes surfaces that wrap up and around the side surfaces of the foot, in order to better control the foot position during transitional loading due to foot-strike motions in any direction.

[0035] A sole unit for footwear comprising a spring unit and a dampener, wherein the dampener is placed under tension when the spring is compressed, creating a return force applied to the spring unit.

[0036] The foregoing is not intended to be an exhaustive list of embodiments and features of the present invention. Persons skilled in the art are capable of appreciating other embodiments and features from the following detailed description in conjunction with the drawings.

[0037] These and other embodiments are described in more detail in the following detailed descriptions and the figures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] FIGS. 1 through 22 show representative embodiments of the present invention. Similar features generally have similar reference numbers. Each embodiment has its own series of reference numbers, offset at intervals of one-hundred from those of other embodiments, so that each block of one hundred identifies a particular embodiment and the terminal digits generally identify analogous features.

[0039] FIG. 1A shows a perspective view of an embodiment of a shoe according to the present invention; FIG. 1B shows a side view thereof; FIG. 1C shows a rear view thereof; and FIG. 1D shows a cross-sectional view of FIG. 1C;

[0040] FIG. 2A shows a cross-sectional view of the embodiment in FIG. 1A; FIG. 2B shows a cross-sectional view of an alternative embodiment of a spring unit with scalloped interior surfaces; and FIG. 2C shows a cross-sectional view of an alternative embodiment of a spring unit including a dampening element;

[0041] FIG. 3A shows a perspective view of another embodiment of a spring unit; FIG. 3B shows a side view thereof, without a load; and FIG. 3C shows an isolated view thereof under a dynamic load;

[0042] FIG. 4 shows an embodiment of a spring unit comprising multiple spring cells;

[0043] FIG. 5 shows another embodiment of a spring unit comprising multiple spring cells;

[0044] FIG. 6 shows an embodiment of a spring unit comprising a three-dimensional truss array;

[0045] FIG. 7A shows a spring unit including a dampener; FIG. 7B is an isolated view thereof; and FIG. 7C shows a spring and dampener under linear load;

[0046] FIG. 8A shows another embodiment of a spring-and-dampener system; FIG. 8B shows a cross-section thereof; and FIG. 8C shows an exploded view thereof;

[0047] FIG. 9 shows a variation of a spring unit and dampener system;

[0048] FIG. 10 shows another variation of a spring unit, in this case with a profile shaped like an elongated ellipse;

[0049] FIG. 11A shows a spring element similar to the embodiment of FIG. 3; and FIG. 11B shows a cut-away view thereof;

[0050] FIG. 12 shows a variation of the embodiment of FIG. 4;

[0051] FIG. 13 shows another variation of a spring unit, in this case with a generally trapezoidal profile with the forefoot end narrower than the rearfoot end.

[0052] FIG. 14A shows an embodiment of a spring unit with rib-like elements that extend upwards around the shoe upper; FIG. 14A also shows internal contact bumpers applicable to any embodiment with a transverse opening; and FIGS. 14B, 14C, 14D, and 14E show alternative cross-sections to illustrate contemplated variations of contact bumpers;

[0053] FIG. 15A shows a rear view of a spring unit comprising a set of spring cells wrapped around the heel; and FIG. 15B shows a variation thereof to show a different orientation of a central spring cell;

[0054] FIG. 16A shows a rear view of a spring unit comprising a set of symmetrically interlocking spring cells; and FIG. 16B shows an asymmetrical variation thereof;

[0055] FIG. 17A shows another embodiment of a spring unit; and FIGS. 17B and 17C show variations thereof;

[0056] FIG. 18 shows a spring unit with a wrap-around tension dampener;

[0057] FIG. 19 shows another example of a combination spring unit with dampener; and

[0058] FIG. 20 shows further embodiments according to the principles of the present invention. Those skilled in the art will appreciate, based on the teachings herein disclosed, the inventive aspects of these further embodiments.

[0059] FIG. 21 is a diagram illustrating typical load transition lines encountered by a runner and an exemplary placement of spring units relative to the load transition lines.

[0060] FIG. 22 is a diagram of lines of symmetry for a shoe or foot and spring units in non-symmetrical alignment therewith based on the force transition lines of FIG. 21.

DETAILED DESCRIPTION OF THE INVENTION

[0061] Referring to FIG. 1A and FIG. 1B, shoe 10 comprises an upper 12 and a sole unit 14. Sole unit 14 includes a forefoot section, midfoot section, and rearfoot (or heel) section. Sole unit 14 further includes a lateral half and a medial half. In the embodiment shown, sole unit 14 incorporates in its rearfoot section a three-dimensional progressive force-tuned spring unit 16. Sole unit 14 also includes an outsole 13 for ground contact and conventional midsole material 15 in the forefoot area as well as, optionally, the surfaces adjacent to spring 16. The spring unit is shown in the rearfoot; however, as will be discussed in more detail, it may be incorporated as one or more elements extending beneath the wearer's whole foot.

[0062] As used herewithin, "shoe" refers to footwear generally and includes shoes, sandals, boots, and other footwear articles. "Sole unit" generally may comprise a midsole for energy absorption and/or return; an outsole material for surface contact and abrasion resistance and/or traction; or a single unit providing such midsole or outsole functions. While a sole unit would generally extend the length of the shoe, a sole unit could also comprise a unit that extends for a lesser area, such as, just the forefoot or rearfoot portion, or some other area of lesser length or width. "Spring rate" refers to spring resistance in response to compression, where a spring unit may have a plurality of spring rates as a result of variations in spring unit wall thickness, spring unit profile, and other features.

[0063] Looking more specifically at spring unit 16, which will be discussed as representative of spring units according to the present invention, spring unit 16 comprises a continuous closed-curve structure with an opening 18 oriented transverse to the longitudinal axis to the wearer's foot. For clarity, all figures depict a single spring unit 16 placed in the rearfoot section of sole unit 14, substantially under the standing wearer's heel. This depiction and the corresponding discussion is representative and exemplary. The use of multiple spring units 16 is within the scope of the present invention. The use of one or more spring units 16 placed in the rearfoot, midfoot, or forefoot sections of a shoe, alone or in any combination, is within the scope of the present invention. Furthermore, one or more spring units 16 may partly or wholly replace part or all of the conventional midsole material in any portion of a sole unit.

[0064] Referring to FIGS. 1C and 1D, which shows a rear view and cross-section thereof of a shoe 10 according the present invention, shoe 10 has a spring 16a on a medial side of a midline 20 and another spring 16b on the lateral side of midline 20. The curved surface of each surface 16a and 16b extends from a point of about the end of the wearer's heel across the calcaneus and to about the midfoot of the wearer extending up to about the metatarsal area. The side-view profile of spring unit 16a and 16b has an approximately trapezoidal shape, typically with rounded corners to improve fatigue resistance by avoiding squared corners.

[0065] Viewed from the side, the rear-most portion (heel) 22 of the embodiment of FIG. 1B is lower than the front-most portion 24, in order to help propagate controlled directional spring collapse.

[0066] Viewed transversely, as shown in FIG. 2A, the spring shape will vary in cross-section from the outside edges 26 to the inner-most edge 28. For example, in the embodiment of FIG. 2A, the cross-section narrows towards the middle and flares out again towards inner-most edge 28 in an irregular fashion. The axis of all the complex surfaces is oriented in line with the heel transition and toe-off. In a typical foot strike, the load transitions cross from the lateral rear heel strike, across the midline of the foot, to a medial toe-off. For example, referring to FIG. 2A, which is a cross-section of spring units 16a and 16b of FIG. 1A, taken along line 2A-2A in FIG. 1C, there is a constantly variable geometry of each spring unit 16. In this case, the spring units 16a and 16b are mirror images of one another. However, each side 16a or 16b may be tuned to a different configuration to enhance or reduce stability.

[0067] Generally, from outer-most edges of the upper surface and lower surface to inner-most edges 28, the sections, thicknesses, and angles are constantly varying in order to provide structural dynamics in order to propagate collapse and support in-line with natural foot-stride transitions. In the embodiment of FIG. 2A, the narrowest separations of the top 30a and bottom 30b portions the sections are raised and thicker in order to offer strategic stiffening relative to normal foot stride moving laterally to point 30a and b. The separation between the surfaces diverges, and the spring becomes thinner, to offer a smooth spring transitions to a lighter spring-rate. Accordingly, by varying the separation of surfaces and the thickness of the surfaces, one or more spring-rate changes may be provided in any one location, and spring unit 16 can be designed in an adaptive way to suit different requirements and individual characteristics.

[0068] FIG. 2B, an alternative cross-section to FIG. 1, shows a more-complex transverse profile intended to stiffen spring unit 16 by virtue of its corrugated nature. FIG. 2C shows alternative embodiment of spring unit 16 with included dampener 40.

[0069] Contemplated materials for spring unit 14 include injected thermoplastics, such as, but not limited to, Hytrel polymer, PEBAX, and TPU, as well as other resilient polymers, thermo-set plastics, and metallic materials known in the art, alone or in combination, that can be shaped and formed into complex sections and shapes. Contemplated fabrication methods include molding, injection molding, direct-injection molding, one-time molding, composite molding, insert molding, co-molding separate materials, or other techniques known in the art, alone or in combination. Contemplated fabrication or assembly methods include adhesives, bonding agents, welding, mechanical bonding, or interlocking shapes, alone or in combination. Laminated structures are within the scope of the present invention.

[0070] FIGS. 3A and 3B show shoe 310 including another embodiment of a three-dimensional progressive force-tuned spring unit 316 according to the principles of the present invention. The curves in this embodiment are non-uniform and can be designed to suit the directional forces common in complex foot-strike motions, incorporating non-uniform sections across the surfaces to further compensate for directional loads. In this case, spring unit 316 has a profile of a closed continuous curve and is located at the heel similarly to spring unit 16 in FIGS. 1 and 2. However, spring unit 316, moving from the rearfoot to the midfoot, has a different profile than that of spring unit 16 in FIG. 1 to provide a tuned response to specifically contemplated forces. As shown in FIG. 3B, spring unit 316 comprises a top wall 332, a bottom wall 334, a forward surface 324, and a rear surface 322. The different surfaces merge without sharp corners. Moving from rear surface 322 towards forward surface 324, surfaces 332 and 334 generally converge towards the midfoot. This profile contrasts with that of spring unit 16, where the top and bottom walls generally diverge towards the midfoot. (FIG. 10 shows another variation with an elongated-elliptical profile; and FIG. 13 shows yet another variation where the top wall is longer than the bottom wall and the narrow end is toward the forefoot of the shoe.)

[0071] The reason for the difference in configuration is that sole unit 16 is oriented in shoe 10 for court or lateral sport applications, in which containing initial heel-strike loads is not as important as containing lateral loads. Spring unit 16 therefore needs to ease the initial crash propagation, allowing a more-acute transition to lateral containment. Spring unit 316, in contrast, is designed for a linear sports shoe, such as a running shoe, where a larger moment of force needs to be contained in the lateral heel strike area. Spring unit 316 then transitions into a midfoot load. In shoe 10, as shown in FIGS. 1A and 1B, the rear-most edge moving 22 forward towards front-most portion 24 tapers forward to the front of the shoe; whereas shoe 310, as shown in FIG. 3A, the bottom-most portion tapers back from the heel up towards the rear-most portion. The sectional properties of the embodiment of FIG. 3A are similar to those of the embodiment of FIG. 2A and complex in surface, shape, and thicknesses throughout.

[0072] FIG. 3B, a side view of the spring unit 316 in FIG. 3A, shows spring unit 316 without load or in static load. FIG. 3C shows an isolated view of spring unit 316 under a dynamic load such as might occur during running heel strike. The top arrows indicate a force vector, and the lower arrows indicate direction of the spring deformation under the load indicated by the upper arrows. After the load is removed, the spring resiliently returns to the configuration of FIGS. 3A and 3B.

[0073] In FIGS. 3A, 3B, and 3C, which depict an embodiment for a linear application such as running, two or more spring unit devices may be positioned under the foot in order to manage different foot-strike load-transitions and for particular biomechanical advantage. For example, shoe might have heel-strike device comprising a spring unit selected for the lateral heel and placed there, plus a second spring unit selected for the forward part of medial heel and placed there, with angles appropriate for transition of loads for rear heel-strike to medial midfoot step, and then forward into the forefoot part of the step. Furthermore, differences in sectional thicknesses can be used to resist the loads in a transitioning matter, in order to soften transitions as the foot-strike forces travel from rearfoot through medial heel to rear forefoot.

[0074] Referring now to FIG. 4, which depicts another embodiment of a spring unit 416 comprising several more, smaller spring cells 416a-n, where "n" is some particular total number of spring cells. Each spring cell 416a-n comprises a top wall 432 and a bottom wall 434. In this case, the spring cells 416a-n may be connected by a connecting element 438. Preferably, spring cells 416a-n and connecting element 438 are integrally manufactured. In a variation, a connecting element 438 may be connected by a dampener 440. Dampener 440 may be, for example, co-molded with the spring unit 416 or bonded using adhesives or using other bonding or welding techniques.

[0075] Top wall 432 and bottom wall 434 define an opening 436. Spring unit 416 therefore has a first profile along a longitudinal line that is generally a diamond shape. However, as in other embodiments, the diamond has rounded corners as opposed to sharper pointed corners to provide resilience and to improve fatigue resistance of the materials under stress cycles. In addition to diamond-shapes, profiles may range from trapezoidal, oval, curved, or compound forms. Spring cells 416a-n are connected to facilitate load transfer from cell to cell, during stages between initial foot strike and natural stepping motion. The use of multiple, smaller spring cells 416a-n effectively minimizes the wearer's perception of load transfer. Multiple, smaller cells 416a-n may be separated horizontally as well as vertically. The spring unit 416 shown in FIG. 4 may have a transverse profile defined by top and bottom walls 432 and 434, similar to what was shown and described in FIGS. 1 through 3.

[0076] FIG. 5 shows another example of a spring unit 516 comprised of multiple spring cells 516a-n, where "n" is some particular total number of spring cells. In the embodiment of FIG. 5, spring cells 516a-n are not connected via a connector, such as 436. Instead, spring cells 516a-n are separated in the sole unit 514, by, for example, a conventional midsole material 515. In contrast to the spring cells of FIG. 4, spring cells 516a-n are vertically displaced from one another. In particular, spring cell 516b is slightly vertically higher than 516a. In spring cell 516a, there is a top wall 532a and a bottom wall 534a. Top wall 532a is non-linear and has a curved form, while bottom wall 534a is generally linear or slightly curved. Spring cell 516b has a similar configuration, but it is reversed, so that top wall 516a generally corresponds to bottom wall 516b. Surfaces 517a and 517b are generally parallel to create a nested arrangement of spring cells 516a-n. Nesting or intersecting spring-cell shapes interact when compressed, in effect spreading the load. Again, the transverse profile for spring cells 516a and 516b would be according to the same principles as the embodiments of earlier figures.

[0077] FIG. 6 shows another embodiment of a spring unit 616 according to the present invention where the spring unit is a complex, three-dimensional truss-array. In the embodiments previously discussed, spring units such as 16, 316, 416, and 516 optionally may be integrated with traditional foam midsole materials 15, 315, 415, and 515. The embodiment of FIG. 6 is particularly intended for use without being incorporated or otherwise integrated with foam or other traditional midsole material. This monolithic structure includes multiple spring cells 616a-n; and, optionally, a rear-heel spring cell 616c. The FIG. 6 configuration is similar to that of FIG. 5. However, the embodiment of FIG. 6 facilitates a connection to upper 612. For example, spring unit 616 can be made to have an upper, outer surface that conforms to the shape of the bottom of the foot.

[0078] Spring unit 616 may also include one or more ribs 617 that wrap up and around any part of the foot, in order to better-control foot position during transitional loading or foot-strike motions in any direction. For example, spring unit 616 may comprise one or more vertically extending ribs that support and surround the base of the foot, thereby enhancing the effect of the under-foot spring units. In this regard, upper 612 of shoe 610 may directly connect to the upper outer surface of the configuration. A major benefit of the spring-array structure of FIG. 6 is that it affords the ability to maximize the open areas, minimize weight, and enhance consumer interest and marketability of the shoe.

[0079] The various embodiments of spring units 16, 316, 416, 516 and so on discussed herein may optionally be integrated with one or more dampeners to provide enhanced functionality. "Dampening" generally refers to the ability of certain materials to reduce the amplitude of oscillations, vibrations, or waves. In a shoe, shock from impact generates compression waves or other vibrations within the sole unit and particularly within spring unit 16, which by design stores energy during foot strike and releases it by toe-off. A purpose of a dampener is to control and deaden "ringing" oscillations within sole unit 14 and spring unit 16. As used herein, single or multiple dampeners are components of spring unit 16 are meant to modify the effects of the energy stored in the spring unit 16 and released after foot strike. A spring unit with a dampener absorbs and releases energy more slowly and efficiently than one without a dampener.

[0080] Contemplated dampening materials include visco-elastomer which may include various polyurethanes or gels. In addition, plain elastomer materials may be used; however, they may not provide as desirable dampening qualities on the spring unit as a visco-elastomer. Contemplated fabrication methods include molding, injection molding, direct-injection molding, one-time molding, composite molding, insert molding, co-molding separate materials, or other techniques known in the art, alone or in combination. Contemplated fabrication or assembly methods include adhesives, bonding agents, welding, mechanical bonding, or other mechanical or chemical fastening means know to persons in the art, alone or in combination. Laminated dampener structures are within the scope of the present invention.

[0081] FIG. 7A shows a spring unit 716 generally similar to that shown in earlier embodiments but including a dampener 740. In the embodiment of FIG. 7A, dampener 740 is oriented along a longitudinal line to agree with the longitudinal expansion and contraction of the spring unit 716, thereby enabling dampener 740 to interact with spring unit 716. Spring unit 716 has a top wall 732 and a bottom wall 732 connected by one or more elastomeric dividers 742. A slight curvature in each divider 742 biases the divider to flex in a predetermined direction when compressed. As shown, dividers 742 are approximately vertical, but non-vertical dividers 742 are within the scope of the present invention. As shown, dividers 742 define a single interior space, but the number of interior spaces depends on the number of dividers 742.

[0082] Dampener 740 has a shank 744 terminated on at least one end by a head 746. Shank 744 passes through each divider 742 via an aperture 748, seen best in FIG. 7B. Head 746 has a larger diameter than aperture 748, locking head 746 against divider 742 in the manner of a rivet head. Head 746 and divider 742 may have an interference fit or may be affixed through adhesives or other chemical or mechanical attachment means known in the art. FIG. 7B shows these structures in isolation, removing surrounding the midsole 715 for clarity. FIG. 7B also shows that a spring unit 716 may comprise multiple spring cells and dampeners 740 which may be identical or separately specified according to the location of each cell in the shoe 710.

[0083] Compressing spring unit 716 forces top wall 732 and bottom wall 734 closer together. Dividers 742 are elastomeric structures connected to walls 732 and 734, so the reduction in distance between walls 732 and 734 tends to increase the distance between dividers 742. For example, as shown in FIG. 7C, a "vertical" compressive load indicated by the large "vertical" arrows deforms the spring unit 716 "horizontally" as shown by the smaller "horizontal" arrows, and dividers 742 accommodate this compression by spreading apart as shown. This expansion places dampener 740, held in place by heads 746, under tension. Dampener 740 thus constrains the expansion of dividers 742. The nature of the counterforce introduced by dampener 740 depends on the thickness, profile, and other features of shank 744 as well as the selection of materials for dampener 740. In general, therefore, dampener 740 absorbs energy on loading (FIG. 7C) and releases energy when it returns to its unloaded state (FIG. 7A).

[0084] Preferably, dampener 742 is mounted in a static or unloaded state. Static mounting enables dampener 740 to most-effectively address compression dampening and rebound dampening.

[0085] Dampener 740 may take on several configurations, parallel to the ground, mounted at an angle, or opposing surfaces in the spring, under tension or not under tension. In addition to mounting the dampener, it could be fully or partially circumferential around the spring unit; or it can be related to a specific spring cell or interconnect and interact with multiple spring cells. FIG. 18 shows a related embodiment with a single divider and a wrap-around dampener.

[0086] FIG. 8A shows another embodiment of a spring-and-dampener system in accordance with the principles of the present invention. Shoe 810 includes a dampener 840, generally aligned along the longitudinal axis of spring unit 816 and connected to opposing surfaces in the spring unit. Dampener 840 may be formed as a film or as a thin, wide band of elastomeric or visco-elastomeric material that expands transversely across the transverse action of spring unit 816. This shape allows ease of assembly, lightness in weight, ease of construction, and adds visual drama. Dampener 840 may connect as described above for the embodiment in FIG. 7A. In this case, dampener 840 includes apertures 844 for receiving pin elements 845 disposed on the spring unit 816 or elsewhere on the spring element, as shown in FIG. 8C. Here again, dampener 840 may be placed under tension when spring unit 816 is in the unloaded state.

[0087] Spring unit 816 shown in FIG. 8A includes an optional contact-bumper 848 that interacts with top wall 832 and bottom wall 834 when the spring unit 816 is under a predetermined load. Bumper 848 may act to limit travel of the top and bottom walls, to dampen impact forces, or both. Example materials for dampener 840 include any number of polymers, including polyurethanes and polyethylenes, fabricated by conventional molding practices or by film. Bumper 848 on dampener 840 may be made of the same material as dampener 840 or from other materials, including visco-elastomers, air bags, fluid-filed bags or compartments, cork, or rubber, alone or in combination. Bumper 848 can exhibit splayed or widening surfaces, which are intended to offer increasing or decreasing levels of dampening. Although only a single bumper 848 is shown on dampener 840, it is also contemplated that multiple bumpers 848 could be distributed in or along the dampener 840. Further, multiple dampeners 840 may be distributed in the spring unit 816.

[0088] FIG. 8B shows the spring and dampener of FIG. 8A in a cross-section taken along line B-B. FIG. 8C shows an exploded view of the assembly spring unit 816 and dampener 840.

[0089] FIG. 9 shows a shoe 910 with a variation of the spring-and-dampener system according to the present invention. In this case, the dampener 940 is connected in alternating fashion along points on the top and bottom elements of the spring unit 916. An elastomer or visco-elastomer can be woven under tension on various surfaces on the inside of the spring to control dampening as well as sheer elements, in the fashion of a spoked bicycle wheel. The embodiment of FIG. 9 is much like a tensegerity structure, where the tensile elements are elastic of deformable.

[0090] FIG. 10 shows another variation of a spring unit 1016 according to the present invention. In this case, spring unit 1016 has a generally elliptical shape with top wall 1032 and a bottom wall 1034. In this spring unit 1016, the rearfoot end of the ellipse has a greater radius than the midfoot end of the ellipse. This aspect is similar to the embodiment of FIG. 3, which is intended for a linear sports application.

[0091] FIG. 11A shows a spring unit 1116 similar to that of FIGS. 1A and 3A. FIGS. 1 and 11 both show lateral and medial spring cells. The FIG. 1 embodiment does not have a center spring cell between the lateral and medial cells. The FIG. 11 embodiment shows an additional, central spring cell.

[0092] FIG. 12 shows a variation of the embodiment of FIG. 4 with multiple spring cells 1216a-n spaced longitudinally and vertically. Spring cells 1216a-n are nested together so that they may advantageously connected in a manner similar to that described in FIG. 5.

[0093] FIG. 13 shows another embodiment similar to those of FIGS. 1, 3, and 10. In FIG. 13, spring unit 1316 has generally trapezoidal profile with the forefoot end narrower than the rearfoot end.

[0094] FIG. 14A shows an embodiment of a spring unit 1416 according to the present invention comprising a plurality of ribs 1417 that extend outside the midsole to the outer surface of upper 1412 of shoe 1410. As shown, ribs 1471 surround the foot between the ankle and the heel, but other placement is within the scope of the present invention. Ribs 1417 may be attached by interference fit, adhesives, or other chemical or mechanical bonding agents listed elsewhere. Any embodiment of a spring unit disclosed herein may include ribs like ribs 1417.

[0095] Spring unit 1416 also has a plurality of bumpers spaced along top wall 1432 and bottom wall 1434. Compression reduces the distance between top wall 1432 and bottom wall 1432. At a predetermined distance, the upper bumper strikes the corresponding lower bumper, limiting the travel of spring unit 1416. The distance between each upper and lower bumper is one factor controlling the amount of compression required to make contact. The counterforce produced by contact between the bumpers depends in part on the choice of bumper material.

[0096] FIG. 14B shows a cross-section of spring unit 1410 taken along line B-B. in FIG. 14A, and FIG. 14C shows a cross-section of spring unit 1410 taken along line C-C in FIG. 14A. FIG. 14 D and FIG. 14E show alternative cross-sections of spring units to illustrate a library of contemplated bumper embodiments. Any of the spring units disclosed herein may additionally comprise any of these bumper embodiments, alone or in combination. Internal bumpers of the sort shown in FIGS. 14 A, B, C, D, and E are an independently variable inventive aspect and may be adapted to any spring unit opening disclosed herein.

[0097] FIG. 15A shows a rear view of a shoe incorporating spring unit 1516 comprising a plurality of spring cells 1516a-n according to the present invention. The embodiment of FIG. 15A shows that the lateral spring cell 1516a, medial spring cell 1516b, or both can wrap around some or all the heel in a longitudinal direction. FIG. 15B shows a variation of the FIG. 15A embodiment to show that one or more central spring cells 1516c disposed between the lateral cell 1516a and medial cell 1516b in the rear heel may take on different orientations for tuned control of impact forces. The embodiment of FIG. 15B inverts central cell 1516c with respect to that shown in FIG. 15A, so that the apex of its substantially triangular profile is at on the bottom instead of the top. Spring unit 1516 may have multiple central cells 1516c. The shape of a central cell 1516c may differ from the approximately triangular shape shown in FIGS. 15A and 15B; for example, the shape may be circular, oval, rectangular, trapezoidal, and so on, according to the particular purpose of the shoe. Furthermore, the angular orientation of one or more central cells 1516c may differ from that shown. In FIG. 15B, for example, the major axis is substantially vertical; but any angle is within the scope of the present invention.

[0098] FIG. 16A shows a different rear-spring configuration where spring unit 1616. comprises a plurality of spring cells 1616a-n disposed in interlocking or nested configuration. As shown, central cells 1616c, 1616d, and 1616e are arranged as a series of interlocking triangular forms. As with the embodiment of FIG. 5A, the nesting or intersecting spring-cell shapes interact when compressed, in effect spreading the load. The embodiment of FIG. 16A is a symmetrical configuration and therefore deals with force symmetrically. In contrast, FIG. 16B shows asymmetrical interlocking spring cells 1616a-n. The heel also includes a void that functions as a crash structure. FIG. 16B thus shows spring-unit embodiment that relies on two surfaces which are parts of different components working together to provide the necessary elements of the art.

[0099] FIG. 17A shows another embodiment spring unit 1710 according to the present invention wherein the plurality of transversely oriented reinforcement elements spaced along the surface of the opening of the spring unit. The reinforcement elements may be used to control the rigidity. By varying the thickness or span of the reinforcement of the elements, the spring may be tuned.

[0100] FIG. 17B shows a variation of the spring unit of FIG. 17A, wherein the reinforcement elements are disposed around the outer surface of the spring element. FIG. 17C shows a more cylindrical spring with longitudinal ribs over the outer surface.

[0101] FIG. 18 shows a spring unit 1810 with a dampener 1840. The embodiment of FIG. 18 generally combines the spring unit and dampener of FIGS. 7 and 8. As depicted, spring unit 1810 has a divider 1842 with an aperture 1848 like aperture 748. Dampener 1840 has a shaft 1844 and at least one head 1846. Shaft 1844 passes through aperture 1848. Head 1846 therefore sits against the adjacent surface of divider 1842, but head 1846 cannot pull through aperture 1848 because head 1846 has a larger diameter than aperture 1848. Head 1846 and divider 1842 may have an interference fit or may be affixed through adhesives or other chemical or mechanical attachment means known in the art.

[0102] As shown in FIG. 18, shaft 1844 extends outside the spring unit to an attachment point outside spring unit 1816. In this case, shaft 1844 wraps around the heel portion of the shoe upper 1812 and terminates by attachment to upper 1812, for example, to attachment means 1850 in the heel-counter area. Alternatively, dampener 1842 may wrap around the heel or other partial circumference of the foot to a spring unit 1816 on the opposite side of shoe 1810, where dampener 1842 terminates with a second head 1846 trapped against a second divider 1848.

[0103] Under compression, the behavior of spring unit 1816 and dampener 1840 is similar to that of the analogous parts of the embodiment of FIG. 7. Compression reduces the distance between top wall 1832 and bottom wall 1834. In response, divider 1842 deforms in a predetermined manner. For example, in the embodiment of FIG. 18, divider 1842 has a slight slope, where its top end is closer to the toe and its back end is closer to the heel. Under load, this slope induces divider 1842 to lean toward the toe end of the shoe, placing dampener 1840 under tension. Dampener 1842 thereby absorbs and releases energy, modifying the dynamic behavior of spring unit 1816, according to the principles previously discussed.

[0104] FIG. 19 shows another example of a combination spring unit 1916 with a dampener. In this example, spring unit 1910 includes one or more dampeners 1940 extending from the bottom wall to an opposing top wall of the spring unit and can be used to join the two surfaces. The dampener is in this case ridged to facilitate compression; however, it may have any number of constructional configurations.

[0105] FIG. 20 shows further embodiments according to the principles of the present invention. In these embodiments, the springs have varying placements, pairings, and orientations to reflect how custom tuning of a sole unit can be achieved according to the foregoing teachings. Those skilled in the art will appreciate, based on the teachings herein disclosed, the inventive aspects of these further embodiments.

[0106] Persons skilled in the art will recognize that many modifications and variations are possible in the details, materials, and arrangements of the parts and actions which have been described and illustrated in order to explain the nature of this invention and that such modifications and variations do not depart from the spirit and scope of the teachings and claims contained therein.

[0107] While the inventors understand that claims are not a necessary component of a provisional patent application, and therefore have not included detailed claims, the inventors reserve the right to claim, without limitation, at least the following subject matter.

Claims

1. A shoe having a sole unit comprising a spring unit, wherein the spring unit adapted for use in footwear and having at least a top wall and a bottom wall; an opening disposed between the top and bottom walls to allow the top and bottom walls to converge under force; the spring unit comprising a first profile for at least a portion of the top and bottom walls that is generally oriented in a longitudinal axis, and a second profile for at least a portion of the top and bottom walls that is generally oriented along an axis transverse to the longitudinal axis; the first profile providing a plurality of spring rates along the longitudinal axis; and the second profile providing a plurality of spring rates along the transverse axis.

2. The sole unit of claim 1 wherein the first profile generally is converging going from a rearward end of the spring unit toward a frontward end of the spring unit.

3. The sole unit of claim 1 wherein the first profile generally is converging going from a frontward end of the spring unit toward a rearward end of the spring unit.

4. The sole unit of claim 2 wherein the second profile is generally converging going from a lateral side to a medial side.

5. The sole unit of claim 4 wherein there are a plurality of sections of convergence or divergence between the lateral and medial sides of the second profile.

6. The sole unit of claim 1 wherein between the lateral and medial sides of the second profile there are a plurality of sections of convergence or divergence.

7. The sole unit of claim 1 wherein between the front and rear of the spring unit along the longitudinal axis there are a plurality of sections of convergence or divergence.

8. The sole unit of claim 1 wherein along the longitudinal axis, there is a change in the uniformity of the top or bottom walls responsiveness to force due to varying and changing sectional thicknesses throughout the surfaces, together with different material types, hardnesses, and flexibilities the spring unit offers a tuned and structured variety of load resistances, and appropriate directional force management, dependent upon the requirements of the various typical foot-strike and load management requirements.

9. The sole unit of claim 1 wherein the angles of the front and rear surfaces, combined with the radii at adjoining bottom and top walls can be adjusted to accommodate to different load, load direction, and energy transitional requirements, according to the particular purpose of the shoe.

10. The sole unit of claim 1 further comprising a plurality of spring units, which are placed in any and various areas of the underfoot, in any and various configurations, in order to provide many different options of foot-strike force dissipation and transitions, catering to different requirements of various users.

11. The sole unit of claim 1 further comprising a dampener.

12. The sole unit of claim 11 or claim 16 wherein the dampener is associated with at least one surface of the spring unit, so that compression of the spring unit places the dampener under tension, creating a return force applied to the spring unit.

13. The sole unit of claim 1 wherein the spring unit is located at a position in the rear lateral area of the heel of the underfoot, or at a position of the foot which makes contact with the ground first, during stepping or foot-strike motion, can have its long surfaces aligned transversely with this axis appropriate to foot-strike patterns typical to linear stepping motion, motion such as while running, or sideways lateral foot strike such as in court sport activity.

14. The sole unit of claim 1 wherein the spring unit can be made from any material with spring-like, energy absorbing and energy storing qualities, such as polymers, metals, composites, or any appropriate combinations of these.

15. The sole unit of claim 1 wherein the spring unit further comprises at least one bumper to limit travel of opposing walls of the spring unit.

16. A sole unit comprising at least one spring unit, the spring unit having opposing top and bottom walls, spaced along an axis, the spring unit having a plurality of spring rates along at least a portion of the axis, and a dampener disposed between top and bottom walls.

17. The sole unit of claim 16 wherein the dampener is disposed so that the length or elongation of the dampener does not exceed the maximum opening between the surfaces of the spring unit to which it is attached or aligned, thereby coming into tension at the point when the load on the spring unit is released and the forces are returned by the spring unit.

18. The sole unit of claim 1 wherein the spring unit has continuous complex curved surfaces, including an upper, outer surface that conforms to the bottom shape of the foot, in the areas where the spring unit is located.

19. The sole unit of claim 1 wherein the spring unit has an upper, outer surface that conforms to the bottom shape of the foot includes surfaces that wrap up and around the side surfaces of the foot, in order to better control the foot position during transitional loading due to foot-strike motions in any direction.

20. A sole unit for footwear comprising a spring unit and a dampener, wherein the dampener is placed under tension when the spring is compressed, creating a return force applied to the spring unit.

21. A spring unit according to claim 1 wherein through varying, complex sectional shape and dimension the unit provides different and appropriate resistances and spring rates throughout the length and width of the unit