Shock resistant shoe

[0001] Pursuant to 35 USC Section 119, this application claims the benefit of priority from Provisional Application Serial No. 60/345,667 with a filing date of Jan. 4, 2002.

[0002] Not Applicable

[0003] 1. Field of Invention

[0004] In most running, walking, and jumping activities, the return force resulting from foot strikes causes great shock to the body. Repeated foot strikes place great stress on joints and bones, and can cause injuries to the lower back and the rotating joints of the legs. To minimize injury to the body resulting from repeated foot strikes, and also to improve athletic performance, shoe engineers have designed various spring-cushioned shoes. The springs in spring-cushioned shoes are designed to reduce shock to the body during a foot strike, and also to recover and return impact energy to the user.

[0005] One type of spring-cushioned shoe is described in U.S. Pat. No. 6,282,814 to Krafsur et al., which is incorporated herein by reference.

[0006] In most running, walking, and jumping events, the foot follows a prescribed set of motions. The heel impacts the ground first, the weight then shifts forward onto the ball of the foot in a rolling manner, and the toe region provides the last contact with the ground. It is desirable to absorb as much of the impact energy from the both the heel and ball areas of the foot during a foot strike, while still providing a stable landing and not slowing down the user.

[0007] In one aspect, the present invention features a spring cushioned shoe with at least one cone spring disposed within the sole of the shoe. The cone spring includes a large diameter end and an opposing small diameter end. The cone spring is positioned in an inverse orientation, wherein the large diameter end is disposed above the small diameter end. The small diameter end faces downward, toward the outer sole of the shoe, so that the spring returns energy to the user in a manner consistent with the rolling motion of the foot during a foot strike.

[0008] The above-mentioned features of the invention will become more clearly understood from the following detailed description of the invention read together with the drawings in which:

[0009] FIG. 1 is a cross sectional side view of a shoe midsole assembly having cone springs disposed within the heel and ball areas of the assembly.

[0010] FIG. 2 is a plan view of an alternative embodiment of the present invention.

[0011] An embodiment of the present invention will be described below with reference to the accompanying figure.

[0012] Referring to FIG. 1, a midsole assembly 2 includes first and second surfaces 22 and 26, respectively, positioned such that first surface 22 can be adhesively attached to an ordinary outer sole 24. The second surface 26 is designed to attach adhesively to inner sole 25. Inner sole 25 provides contact area 28 for an upper shoe portion (not shown) to be attached to midsole 2.

[0013] Midsole 2 contains vacuities 10 and 12 positioned in the heel and ball areas of midsole 2, respectively. Vacuities 10 and 12 communicate with each other by way of fluid flow pathway 18, which allows the free flow of fluid there between, as described in the co-pending U.S. patent application assigned Ser. No. 09/982,520, which is incorporated herein by reference. Alternatively, the vacuities 10 and 12 and the pathway 18 may be filled, either partially or completely, with a low density, polymeric foam to encapsulate the spring mechanisms described more fully hereinafter.

[0014] A first cone spring 8 is positioned in the heel vacuity 10 of midsole 2. Cone spring 8 has a large diameter terminal end 17, and a small diameter terminal end 19; the large diameter terminal end 17 faces downward, toward the outer sole 24, and the small diameter terminal end 19 faces upward, towards inner sole 25. Terminal end 17 is in mechanical contact with plate 16, to resist lateral movement relative to the plate 16, as by welding, adhesive, virtual interference, engagement in a slot defined in the plate 16 or physical attachment, for example. The small diameter terminal end 19 is firmly attached to a first surface plate 6, to resist lateral movement relative to the plate 6, as by welding, adhesive, virtual interference, engagement in a slot defined in the plate 6 or physical attachment, for example. A textured face of the plate 16 is held in adhesive contact with a lower surface 10a of vacuity 10. Plate 6 is in mechanical contact with the upper surface 10b of the vacuity 10. A spring compression limiter 30 is attached to the axial center of plate 6, in a vertical orientation, to prevent the full compression of cone spring 8 during use.

[0015] Plates 6 and 16 are constructed of sheet metallic material, but could also be made from various other metal or non-metallic materials. The spring compression limiter 30 is made of, e.g., a polymeric material.

[0016] A second cone spring 9 is positioned in ball vacuity 12 of midsole 2. Like cone spring 8, cone spring 9 has a large diameter terminal end 23 and a small diameter terminal end 21. Unlike spring 8, spring 9 is positioned within the ball vacuity such that the large diameter end 23 faces upward, toward inner sole 25, and the smaller diameter end 21 faces downward, toward outer sole 24.

[0017] The second cone spring 9 is positioned between plates 13 and 14 in the ball vacuity 12. A first face of plate 13 is adhesively attached to surface 12a of vacuity 12, and the second face of plate 13 is attached to the small diameter end 21 of spring 9 by a mechanical fixture, or, alternatively, by adhesion. Plate 14 is attached, at one face, to the large diameter end 23 of coil spring 9, and is attached adhesively at its opposite face to inner sole 25. The ball vacuity also includes a compression limiter 30, as described above in connection with heel vacuity 10.

[0018] Positioning the ball area cone spring 9 in this inverse orientation takes into account the rolling motion of the ball portion of the foot during a foot strike. This inverse orientation allows the outer sole, as it rolls over the ball of the foot, to pivot over a smaller surface of spring. As a result, the spring 9 returns force to the user over a greater portion of the ball strike, and therefore returns a greater percentage of the impact energy to the user.

[0019] The cone springs 8 and 9 are both multi-turn coil springs, having a large diameter terminal end and a small diameter terminal end, as described above and as shown in FIG. 1. The springs 8 and 9 taper evenly from the large diameter ends to the small diameter ends. The springs can be made from metal, or various non-metallic polymeric materials.

[0020] Other embodiments are also possible. For example, both the heel and ball area cone springs could be disposed in the inverse orientation, with the small diameter end facing downward, as shown above for cone spring 9.

[0021] The cone springs 8 and 9 need not have a conical shape. So long as the springs have a small diameter end and an opposing large diameter end, the spring need not taper evenly from the large end to the small end. For example, the diameter might remain constant for a portion near the large diameter end, and then taper to the small diameter end. Alternatively, the spring may bulge in the middle section.

[0022] As depicted in FIG. 2, a wave spring 34 may be placed in the heel vacuity 10 instead of a cone spring. Such an embodiment includes a wave spring in the heel area, as described, e.g., in U.S. Pat. No. 6,282,814, and at least one inversely oriented cone spring 9 in the ball area, as described above.

[0023] Multiple springs may be included in each vacuity. For example, the heel vacuity 10 may include multiple wave springs, multiple cone springs, or a combination of wave springs and cone springs. Similarly, ball vacuity 12 may include multiple inversely oriented cone springs, or a combination of wave springs and inversely oriented cone springs. Alternatively, the multiple heel and ball springs may be disposed within multiple heel and ball vacuities.

[0024] The springs may be disposed within the heel and ball vacuities using, e.g., countersunk volumes and shim ends, as described in U.S. Pat. No. 6,282,814.

[0025] From the foregoing description, it will be recognized by those skilled in the art that an improved sole assembly has been provided.

[0026] While the present invention has been illustrated by description of several embodiments and while the illustrative embodiment has been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant's general inventive concept.