Athletic Shoe Having Spring Cushioned Midsole

1. Field of the Invention:

The invention relates to an athletic shoe and particularly to an athletic shoe having a spring foam midsole which is advantageous from a standpoint of reducing stresses and dissipating energy associated with various athletic activities while also maintaining satisfactory stability.

2. Discussion of Background:

In order to provide improved cushioning and impact absorbtion, athletic shoes have been provided with air cushions disposed within the sole structure of the shoe. However, air cushioned arrangements can be undesirable in that the stability of the shoe is diminished as a result of the air cushioned support. As an alternative to air cushions, athletic shoes have been provided with cushioning wedges disposed between the insole and the outsole of the shoe. By way of example, U.S. Pat. No. 5,222,311 to Lin discloses a shoe in which a cushioning wedge is disposed within a receptacle of an outsole. In the Lin arrangement, closely packed side-by-side cushioning elements are provided in the form of curved projections extending from a base member. With such a closely packed arrangement, the cushioning elements effectively act as a unit. As a result, if a soft cushioning material is utilized the stability of the shoe is compromised, and the shoe can be hazardous when participating in various athletic activities. By contrast, when a harder cushioning material is utilized, the capacity of the cushioning wedge to relieve stresses or absorb impacts is reduced.

U.S. Pat. No. 4,485,863 also discloses a shoe in which cushioning elements are disposed in side-by-side relation. In addition a window extends through the side of the sole of the shoe so that the cushioning elements can be observed from the exterior of the shoe. As discussed above, with such an arrangement, the cushioning assembly is less than optimal from a combined stability and impact absorption standpoint. In addition, by providing a window which extends through the side of the shoe, the structural integrity of the shoe is diminished, or the shoe must be constructed to accommodate for the loss of strength resulting from the window opening.

It is an object of the present invention to provide an improved athletic shoe having desirable cushioning/impact absorbing qualities while maintaining a high level of stability.

It is another object of the invention to provide an athletic shoe having a midsole which includes a cushioning unit having a modulator member with a plurality of projections extending therefrom, with the projections spaced with respect to one another so that the interaction between the projections and the modulator provide a spring cushioning arrangement which stably dampens impact forces.

It is yet another object of the invention to provide an athletic shoe having an arrangement of cushioning elements which provide increased cushioning/impact absorption in regions subjected to higher forces or stresses, while areas requiring support have lower cushioning/impact absorption qualities, with the overall construction providing a stable, cushioned midsole assembly.

The foregoing, and additional objects and advantages are achieved in accordance with the present invention which includes a midsole cushioning assembly having a modulator or base of a substantial thickness, with a plurality of spaced projections extending from the modulator. In a preferred embodiment, the midsole of the shoe includes a pocket which receives a spring foam cushioning assembly of the present invention, and the spring foam assembly includes a midsole unit having a modulator portion of a substantial thickness, with a plurality of spaced projections provided in the forefoot and heel regions, while the center region of the midsole unit is substantially flat. An additional heel unit is also provided, and the heel unit also includes a modulator or base member having projections extending therefrom, with the projections of the heel unit facing the corresponding projections of the heel portion of the midsole unit. The arrangement of the present invention is advantageous in that the projections are sufficiently spaced so that they can substantially independently interact with the modulator or base member, to thereby provide a spring cushioning effect. In addition, by providing projections in selected regions of the midsole unit, greater support is provided in certain regions (such as in the arch region of the shoe), while greater cushioning is provided in regions subjected to higher impact forces (such as in the heel region and forefoot regions). In addition, by providing a double cushioning arrangement in the heel region, with projection of the cushions facing each other, this region is particularly efficient in dissipating energy and absorbing undesirable impact forces. Moreover, by utilizing spaced projections which interact with the modulator independently, a stable cushioning effect is obtained. The stability of the cushioned midsole is further enhanced by disposing the cushioning assembly within a pocket of the shoe midsole. The midsole pocket includes three pocket portions having differing depths in the preferred embodiment.

In accordance with a further aspect of the invention, a mock window display is provided on the exterior of the shoe, to display, e.g., a mock of the cushioning elements. This mock display is advantageous in providing information regarding the structure/function of the cushioning elements, while minimizing any compromise in the structural integrity of the shoe.

A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood with reference to the following detailed description, particularly when considered in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of the sole, midsole, and midsole cushioning assembly of the present invention;

FIGS. 2A and 2B respectively depict the midsole unit and heel unit which form the preferred cushioning assembly of the present invention;

FIG. 3 is a side cross-sectional view of the midsole unit and heel unit of the present invention;

FIG. 4 depicts an alternate configuration of a projection of the cushioning assembly of the present invention. and FIGS. 5A-5E depict a modified form of the invention in which a mock window is provided in the shoe exterior.

Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, FIG. 1 depicts the sole/midsole assembly of the present invention, and particularly the relationship of the sole, midsole and midsole cushioning assembly of the present invention. As shown in FIG. 1, a midsole 4 is disposed above an outsole 2. Upon assembly of the shoe, the midsole 4 is fastened to the sole 2, e.g., utilizing an adhesive.

The midsole includes a pocket 6 having differing depths in order to receive a spring foam midsole cushioning assembly of the present invention as discussed further hereinafter. In a particularly preferred form of the invention, the pocket of the midsole includes an intermediate depth pocket portion 6a, a shallow depth pocket portion 6b, and a deep depth pocket portion 6c. The spring foam midsole cushioning assembly includes a midsole unit 8 and a heel unit 10. As also shown in FIG. 1, the midsole unit 8 includes a modulator portion 8a having a substantial thickness, so that the midsole unit is able to support spaced, independent projections as will be discussed further hereinafter. In a currently preferred form, the modulator or base portion of the midsole unit is formed of a urethane foam material having a Shore C hardness of 60-80, and a thickness of 2-4 mm, with the thickness preferably 2-3 mm. Of course, other materials and proportions are also possible. However, this thickness of the modulator portion has been found advantageous in combination with spaced projections so that the projections substantially independently interact with the modulator to provide a stable spring form cushioned midsole assembly.

Still referring to FIG. 1, the heel unit 10 also includes a base or modulator portion 10a, which may be of the same material and/or thickness as that of the modulator portion 8a of the midsole unit 8. However, the heel unit and modulator portion 10a may also have a different thickness and/or hardness as compared with the midsole unit, if desired.

The forefoot region 9a of the midsole unit 8 is received within the intermediate depth pocket 6a of the midsole 6, while the center region 9b of the midsole unit 8 is received within the shallow depth portion 6b of the midsole pocket 6, and the heel unit 10 and the heel portion 9c of the midsole unit 8 are received within the deep depth portion 6c of the pocket 6.

As shown in FIG. 2A, the midsole unit 8 includes projections 12 disposed in the forefoot 9a and heel 9c regions of the midsole unit, while the central portion 9b is flat. In the embodiment of the invention of FIGS. 1-3, the projections are in the shape of a truncated cone, and are sufficiently spaced so that the projections can act and interact independently with the modulator portion 8a, to provide a stable impact absorbing unit. By way of example, in a presently preferred form of the invention, the projections have a 10 mm diameter at the base (i.e., adjacent to the modulator), with a 5 mm diameter at the top of the projections (i.e., the portion of the projection remote from the modulator portion 8a). In addition, a center to center spacing distance of the projections can be, e.g., 14 mm (providing a base to base spacing of approximately 4 mm). Of course, the spacings and sizings may vary. In the FIG. 2A arrangement, the projections are arranged in staggered rows, to provide a stable distribution of forces over the regions which include projections. However, alternate patterns of projections are also possible.

As shown in FIG. 2B, the heel unit 10 includes projections of the same size and spacing as that of the region 9c of the midsole unit 8. In the preferred form of the invention, the projections of the heel portion 9c and the heel unit 10 face one another as shown in FIG. 3, with the projections of the heel portion of the midsole unit abutting the projections of the heel unit. As a result, an increased spring/cushioning effect is provided in the heel region of the shoe so that the heel region is able to gradually absorb and dissipate substantial energy/impact forces which can be encountered in the heel region.

Utilizing a foam material (e.g., a urethane foam) for the midsole cushioning assembly, and by spacing the projections 12 with respect to one another, the projections are able to act as independent springs spaced about the midsole unit. In addition, by utilizing the double facing projection arrangement in the heel region of the midsole in accordance with the present invention, larger forces are able to be gradually absorbed and dissipated.

As shown in FIG. 3, an inclined portion 10b is provided at the front of the heel unit 10. The inclined 10b portion is disposed upon an inclined portion 6d of the midsole 4 as shown in FIG. 1. This arrangement is advantageous in providing a transition along the midsole between the deep depth portion and the shallow depth portion, while also ensuring that the heel unit is stably disposed in the pocket portion 6c. The inclined heel unit portion 10a and inclined midsole portion 6a avoid an excessively steep transition between the deep depth pocket 6c and the shallow pocket portion 6b, thereby avoiding stress concentrations.

Referring now to FIG. 4, an alternate form of the projections of the present invention is shown. In the arrangement of FIG. 4, a helical or screw like projection 14 is provided, to further enhance the ability of the projections to absorb impact forces and dissipate energy.

FIGS. 5A-E depict an alternate embodiment of the present invention in which a mock window 20 is provided. Although the mock window 20 is disposed at the rear of the shoe and in the midsole 4' portion of the shoe in FIGS. 5A-E, the mock window 20 can be disposed at other positions (e.g. in the sole and/or along the side of the shoe) if desired. The mock window can display a mock version of the cushioning projections disposed in the midsole of the shoe.

The mock window is advantageous in that it avoids the need for an open aperture extending through the shoe as in prior window arrangements. In addition, by utilizing a mock version of the projections, projections 22 of a reduced size (e.g., 20% smaller than actual size) can be provided, thus reducing the size of the mock window required to depict a series of projections. Further, as shown in FIGS. 5A-5E, the projections can be displayed in cross-section, and such a cross-sectional projection display was not possible with prior window arrangements. Moreover, the mock window arrangement is also advantageous in that the mock projections will not exhibit any deterioration of the actual projections which can occur over an extended period of use, so that a prolonged superior appearance is achieved.

As shown in FIGS. 5A-E, the mock window includes a transparent cover 24, and mock projections 22 held in a filler material 26. As shown particularly in FIG. 5E, the filler material 26 can include a tab portion 26a which is received within a recess 24a of the cover 24, so that the mock projections 22 are positioned at a desired distance from the front 24b of the cover 24. The filler material can be, e.g., polyurethane or other estomeric or resin materials, and can provide support to the midsole region of the shoe to compensate for the intrusion of the mock window from a structural standpoint. Preferably, the cover includes arcuate extensions 28 which partially extend bout the heel cup region of the shoe to provide stable positioning of the mock window 20.

As should be apparent from the foregoing, the present invention provides a structure for an athletic shoe which includes a midsole cushioning assembly which is able to gradually absorb impact forces and dissipate energy while also maintaining sufficient stability. In addition, in accordance with a further aspect of the present invention, a mock window can be provided, which avoids shortcomings associated with providing an actual window which extends into the interior of the shoe.

Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.