Open Footwear with Rigid, Porous Surface

Abstract

It is desired to teach an open footwear article where the upper surface contacting the foot is partially combined with, or wholly comprised of, a substantially rigid material that has some degree of open porosity. The purpose of said rigid, porous material serves to immediately absorb perspiration and/or water from the feet. Subsequent drying of the porous, rigid material occurs when the sandal is not in use as water/perspiration are evaporated from within the pores. The porous, rigid material also effects a massaging action while walking. It is the intent of this invention to capture a preferred combination of these two embodiments.

Claims

1. An open footwear article whose contact surface with the foot is partially comprised of a rigid, porous material, and the non-rigid portion of the footwear article is preferably comprised of ethyl-vinyl acetate (EVA), or polyurethane (PU), poly-ethylene (PE), poly-vinyl chloride (PVC), thermo-plastic rubber (TPR) or pure rubber, as well as combinations of these polymers.

2. The article of claim 1, wherein the rigid, porous material has a degree of porosity of 1-40%.

3. The article of claim 2, wherein the rigid, porous material has a degree of porosity of 1-20%.

4. The article of claim 3, wherein the rigid, porous material has a degree of porosity of 1-10%.

5. The article of claim 2, wherein the rigid, porous material has a modulus-of-rigidity of 0.1-25 GPa.

6. The article of claim 5, wherein the rigid, porous material has a modulus-of-rigidity of 0.1-10 GPa.

7. The article of claim 6, wherein the rigid, porous material has a modulus-of-rigidity of 0.1-5 GPa.

8. The article of claim 1, wherein the rigid, porous material is comprised partially or wholly of sandstone.

9. The article of claim 8, wherein the sandstone material deployed is also produced for another application, such as a coaster.

10. An open footwear article whose contact surface with the foot is wholly comprised of a rigid, porous material, and the non-rigid portion of the footwear article is preferably comprised of ethyl-vinyl acetate (EVA), or polyurethane (PU), poly-ethylene (PE), poly-vinyl chloride (PVC), thermo-plastic rubber (TPR) or pure rubber, as well as combinations of these polymers.

11. The article of claim 10, wherein the rigid, porous material has a degree of porosity of 0.1-40%.

12. The article of claim 11, wherein the rigid, porous material has a degree of porosity of 0.1-20%.

13. The article of claim 12, wherein the rigid, porous material has a degree of porosity of 0.1-10%.

14. The article of claim 11, wherein the rigid, porous material has a modulus-of-rigidity of 0.1-25.

15. The article of claim 14, wherein the rigid, porous material has a modulus-of-rigidity of 0.1-10.

16. The article of claim 15, wherein the rigid, porous material has a modulus-of-rigidity of 0.1-5.

17. The article of claim 10, wherein the rigid, porous material is comprised partially or wholly of sandstone.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a depiction of a sandal surface that is being partially modified with a thin, cylindrical, rigid, porous material component.

[0008] FIG. 2 is a depiction of the fully modified sandal in its usable state.

[0009] FIG. 3 is another depiction, wherein the entire surface is comprised of a rigid, porous material.

DETAILED DESCRIPTION OF THE INVENTION

[0010] A description of preferred embodiments will be given in detail with reference to the attached drawings.

[0011] In FIG. 1, a common sandal 16 composed of a flexible, water resistant polymer is shown with a cavity 20 that is designed to receive a thin, cylindrical body comprised of a rigid, porous material 18. The inset in FIG. 1 illustrates that the cavity 20 that accepts the rigid, porous material only partially penetrates the thickness of the sandal sole 16. This rigid, porous material is not meant to be removable; rather, it is illustrated as a means to fabricate the completed assembly 12 in FIG. 2.

[0012] FIG. 2 depicts a fully-assembled preferred embodiment of the subject invention. In this embodiment, the rigid, porous material 18 is cylindrical, and of such a thickness so as to protrude slightly from the main polymer surface of the sandal. Under typical loads from the weight of the wearer, the rigid, porous material should compress to roughly flush with the surface. In this embodiment, the surface is preferably only partially modified with the rigid, porous material, preferably further in areas of contact of the foot, such as the ball and heel areas.

[0013] FIG. 3 depicts a further embodiment, wherein the entire surface of the sandal is comprised of a rigid, porous material 18. Preferably, the rigid, porous material does not comprise the entire body of the sandal. Therefore, the base of the sandal 16 is still comprised of a type of polymer as articulated earlier.

[0014] A preferred embodiment can be taught in the form that the rigid, porous material 18 is comprised partially, substantially, or wholly of sandstone. In this context, sandstone can refer to the broad class of quartz and feldspar combinations that are found in typical sandstones used in commodity applications. When the sandal surface material is comprised partially or wholly of sandstone, an optimum combination of water removal and massaging activity for the bottom of the feet can occur. A particularly advantageous combination involves configuring the subject invention using existing commodity components. Such components include deploying sandstone coasters as the rigid, porous material with a sandal modified to accept them.

[0015] The degree of porosity of the rigid, porous material may vary, but is preferably in the 1 to 40% range, further preferably in the 1 to 20% range, and even further preferably in the 1 to 10% range. Adequate porosity for the removal of liquids should be facilitated without compromising the structural integrity of the rigid, porous material under typical loads. Also, the degree of rigidity of the rigid, porous material can be defined using the modulus-of-rigidity quantity. Preferable materials will have a modulus-of-rigidity in the range of 0.1 to 25 GPa, further preferably in the range 0.1 to 10 GPa, and even further preferably in the range 0.1 to 5 GPa.

[0016] The ideal composition of the sandal body 16 in the preferred embodiment is a flexible polymer, such as such as ethyl-vinyl acetate (EVA), polyurethane (PU), poly-ethylene (PE), poly-vinyl chloride (PVC), thermo-plastic rubbers (TPR) or pure rubber, as well as combinations of these polymers, which are typically employed in waterproof sandals. These combinations may further exist in an open or closed-pore structure. Because such polymers are, to a degree, flexible, they will be compressed under the load of the rigid, porous material. When properly designed, loading weight of the wearer will be partially transmitted through the rigid, porous material to the underlying polymer layer and result in compression. In this way, the rigid, porous material will transmit load to the underlying polymer which will reduce the tendency for the rigid, porous material to fracture under repeated load/unload cycles. Again, under such compression, the cavity 20 is designed such that, under typical compressions, the top surface of the rigid, porous material is not compressed into the sandal body 16 any further than approximately flush with the surface.

[0017] While the present invention has been described with reference to the preferred, illustrative embodiments, it is not to be restricted by these but only by the appended claims. It is to be appreciated that those skilled in the art can change or modify the embodiments without departing from the scope and spirit of the present invention.