Background of the Invention Various attempts have been made to provide improved shock absorption in footwear constructions. For example, U. S. Patent 4,451,994 to Fowler discloses a multi- layer, shock-absorbing, sealed midsole that includes a plurality of transverse support ribs between the layers of the midsole, forming air pockets to provide cushioning, each rib in the upper layer being located above a space between an adjacent pair of ribs in the lower layer.

U. S. Patent 4,798,009 to Colonel et al. discloses springs located in the soles of footwear, the springs being comprised of layers of resilient material spaced apart by compression members, the members extending from one side of each layer, the other side of the layer being smooth, and the members being aligned with and on the other side of the spaces between members on the adjacent layer.

U. S. Patent 5,172,494 to Davidson discloses a foot cushioning device comprising a plurality of interconnecting longitudinal and transverse ribs of varying height extending from the exterior of the device. The taller ribs collapse to the height of the shorter ribs, at which point both the taller and shorter ribs provide resistance to the load.

U. S. Patents. No. 5,233,767 and 5,493,791 to Kramer disclose a midsole construction in which soft plugs or columns extending perpendicularly from a web bulge significantly when compressed by the stepping action of a normal walker, the bulging

serving to move the air between the columns, thus ventillating the shoe while providing cushioning.

These prior devices are relatively complicated in construction, and do not provide a simple, relatively thin, single layer device that can be inexpensively manufactured and assembled into a shoe or boot, yet provides substantial cushioning to the foot of the wearer.

It is therefore an object of the present invention to provide a footwear cushioning insert that is simple in design, relatively inexpensive to manufacture, and relatively thin in cross-section, and yet provides substantial cushioning effect to the wearer of the footwear.

Summary of the Invention The footwear cushioning system of the present invention comprises an insert, preferably for inclusion at the heel portion of the footwear, the insert comprising a single layer of resilient, flexible web material, on one side of which layer is located a first array of projections formed integrally with and extending from the web layer, and on the other side a second array of projections formed integrally with and extending from the web layer, each of the projections in the first array being located on the opposite side of the web from a space between a set of projections in the second array.

In the preferred embodiment here described, the projections in the first array and in the second array are arranged in rows and columns, the projections in the first array being generally button-shaped, and the projections in the second array being in the shape of rectangular boxes, each box having one dimension longer than the other two, the long edges of each box being parallel with the web surface. The length of each box-like projection is about equal to the diameter of one of the button-shaped projections. Each button-shaped projection is located approximately at the center of, but on the opposite side of, the space defined amid a set of four boxes on the other side of the web, so that when a force is applied to the button and the boxes due to the activity of the wearer of

the footwear, the button is moved toward the space amid the set of four boxes, and/or each box is moved toward the space between buttons, as the web resiliently flexes, providing shock-absorbing cushioning to the wearer.

Brief Description of the Drawings FIG. 1 a is plan view of one side of the cushioning insert of the preferred embodiment of the present invention, showing the rectangular, box-like projections arrayed on one side of the web.

FIG. lb is a side elevational view of the cushioning insert of FIG. 1, the shoebox- like projections extending upward from the web, and the button-like projections extending downward.

FIG. lc is a plan view of the button side of the cushioning insert.

FIG. I d is a plan view of the box side of the cushioning insert of FIG. 1, like that of FIG. 1 a, but with the relative location of the button-like projections on the other side of the web being represented by dashed lines.

FIG. 1 e is an side elevational view representing the configuration of the cushioning insert when under load.

FIG. 2 is a plan view of the bottom of a cup insole for a shoe or boot, in which a cavity or pocket has been provided in the lower side of the cup insole to receive the cushioning insert of FIG. 1.

FIG. 3 is a sectional view of the cup insole of FIG. 2 taken along line 3-3 of FIG.

2, but also showing the cushioning insert in place within the cavity or pocket in the cup insole.

FIG. 4 is a representational perspective view of a sandal, illustrating the incorporation of the cushioning insert of the present invention in the heel area of the sole.

FIG. 5 is a cross-sectional view taken along the line 5-5 of FIG. 4, showing the cushioning insert in place within the heel portion of the sandal sole.

Detailed Description of the Preferred Embodiment FIGS. 1 a through 1 d depict a cushioning insert 10 constructed in accordance with a preferred embodiment of the instant invention. As seen in FIG. 1 a, rectangular, shoebox-like projections 12 extend from one side of thin web 14 and are arranged end- to-end in spaced apart relationship, in perpendicular rows and columns separated by approximately the width of a box. The height of each rectangular box 12--i. e., the distance it projects from the web--is slightly less that the width dimension, while the length dimension is about twice the width. In the preferred embodiment here shown the length of each box is about 5mm, the width about 3mm, and the height about 2mm. The web itself is about lmm thick, while the cushioning insert 10 is about 35mm by 45 mm in overall dimension.

FIG. I b depicts box-like projections 12 extending upward from web 14, and button-like projections 16 extending downward therefrom. As indicated, web 14 is preferable a relatively thin, flexible sheet of natural rubber, molded in one piece with solid projections 12 and 16 extending therefrom. In the preferred embodiment here described, the total height or thickness of insert 10, comprising the heights of projections 12 and 16 and the thickness of web 14, is about 5mm.

FIG. I c is a plan view of cushioning insert 10, showing the arrangement of button-like projections 16 on web 14. The buttons are preferably arranged in regular array, the diameter or width of each button at its base being approximately equal to the

long dimension of each box-like projection 12--i. e., about 5mm. Each button extends about 2mm from the web surface.

FIG. 1 d is another plan view of the box side of cushioning insert 10, like FIG.

1 a, but showing in dashed line the relative arrangement of the button-like projections 16 on the other side of web 14. As can be seen from FIGS. 1 b and 1 d, button-like projections 16 are situated opposite the space formed between the long sides of sets of four facing box-like projections 12, so that when a force is applied to insert 10 due to activity of the wearer, a button-like projection 16 will be moved toward the space formed between its corresponding set of box-like projections, and/or the shoebox-like projections simultaneously are moved toward the spaces between the button-like projections, thereby providing cushioning to the footwear wearer as the flexible web material is flexed.

FIG. 1 e illustrates the approximate configuration of the cushioning insert 10 of the instant invention when under load. The button-like projections 16 on one side of web 14 are relatively displaced toward the spaces between box-like projection 12 on the other side of the web, the box-like projections 12 are relatively displaced toward the spaces between buttons 16, and the web 10 takes on a"wavy"appearance. Under such a load, the resilient material of the web 10 and the projections therefrom serve to cushion the impact of the load, providing increasing resistance to further compression of the insert as more force is applied.

A suitable material for cushioning insert 10 is a rubber compound comprising approximately 65% natural rubber (TTR-5L) by volume, 30% polybutadiene (BR-0150), 12% processing oil, 0.1% anti-oxidant (B. H. T.), 0.04% stearic acid, and 0.3% zinc carbonate. This formula yields a compound that is of sufficient strength, durability, and resiliency to provide the desired cushioning. This particular compound has a density of 1.2 g/cc, an elongation of 350%, pull strength of 90 kg/cm, and a durometer of 30Fp on the Shore A scale.

As stated above, projections 12 and 16 are molded integrally with web 14 to form insert 10. The exact shape of the projections from either side of the web is not critical, nor are the precise dimensions set forth above. For example, the"button- shaped"projections could be oval, or cubic, or rectangular, or some other shape.

Likewise, the"box-like"projections could take on other configurations. However, it has been found that the particular shapes utilized in the preferred embodiment here described are effective in providing the desired cushioning. As to the overall dimensions of the insert, again the exact overall size and the precise dimensions here detailed are not critical to the invention. The insert may, for example, be in the same size and shape as the sock liner or cup insert, to provide cushioning to the entire foot, or it may be sized and shaped to provide cushioning to most or all of the heel area.

One of the ways in which the cushioning insert 10 of the preferred embodiment may be employed is by affixing it to the cup liner of a shoe or boot. For example, FIG. 2 depicts the underside of a cup insole 20 that may be inserted into a shoe or boot; a sock liner (not shown) is typically affixed to the upper side. Cup insole 20 may be conventionally molded of flexible rubber or plastic, and a cavity or pocket 22 may be molded into its lower side it for receipt of a cushioning insert 10. FIG. 3 depicts cushioning insert 10 in position in pocket 22, with box-like projections 12 preferably facing upward. Cushioning insert 10 may be affixed within pocket 22 by means of standard adhesives.

Another construction utilizing the preferred embodiment of the cushioning insert of the instant invention is illustrated in FIGS. 4 and 5. Sandal 40 includes sole 42 molded of suitable rubber or plastic material, within which a cushioning insert 10 has been implanted. As best seen in FIG. 5, cushioning insert 10 is housed in a cavity 44 in the bottom of sole 42, permitting insert 10 to be positioned approximately in the middle of the heel portion of sole 42. Preferably, the button-like projections 16 of insert 10 face downward. Plug 46, made of the same material as sole 42, is then introduced into and adhesively affixed within cavity 44 to close the cavity and to hold cushioning insert 10 in place. Adhesive may also be applied to insert 10 to better hold it in position within

sole 42. Alternatively, using known techniques, the cushioning insert may be molded directly into the sole by suspending the cushioning insert in the mold while the sole material in a liquid state is injected into the mold to form the sole. In this construction, the cushioning insert is surrounded by the sole material, and there is no"pocket"formed in the sole and no need for a plug.

It will be readily appreciated by those skilled in the art that the present invention in its broader aspects is not limited to the specific embodiments herein shown and described. Accordingly, variations may be made from the embodiments described herein which are within the scope of the accompanying claims, without departing from the principles of the invention and without sacrificing its chief advantages.