Single-sole sandal having fabric straps and method of attachment

Abstract

A single-sole sandal having fabric straps includes a sole made of a pliable yet durable material and a “Y” shaped strap having a strap retention disc attached thereto so that the strap retention disc may be inserted through an aperture in the sole by deforming the sole, and the sole returns to its original shape to retain the strap in place.

Description

RELATED APPLICATIONS

The present invention claims the benefit of priority to U.S. Provisional Patent Application Ser. No. 60/961,460, filed Jul. 20, 2007, with the same title and currently co-pending.

BACKGROUND OF THE INVENTION

Sandals are a very popular form of footwear. The style and design of sandals varies greatly between manufactures, and have evolved over the years. For instance, one form of sandal that has become a favorite over the last few decades is commonly referred to as the flip-flop. Flip-flops are the most basic of footwear and typically include a thin foam rubber sole with two simple straps running in a “Y” from the sides of the foot to join between the big toe and next toe. The basic flip-flop sandal is held on the foot by the straps passing over the top or around the sides of the foot. Flip-flops are typically made with a pliable foam rubber sole, and molded rubber or plastic straps, most commonly known as “Zori's”. Popular use of flip-flops as simple warm climate beach or outdoor wear has spread through much of the world. An example of a PRIOR ART flip-flop is shown in FIGS. 1 and 2:

FIG. 1 depicts the upper and lower views of a PRIOR ART flip flop and shows the sole, and the positioning and attachment of the strap; and

FIG. 2 is a cross-sectional view of the strap attachment to the sole, showing the strap and strap retention plug, and the plug receiver and the plug bore as formed in the sole.

Referring to FIG. 1, a PRIOR ART flip-flop is shown and includes a planar upper sole made from a pliable rubber compound, typically Ethylene-vinyl acetate (also known as EVA); however other sole materials may be used. A rubber or plastic strap in the shape of a “Y” is attached to the sole at its three endpoints to provide ample room for a wearer of the flip flop to insert his foot between the strap and the sole, with the base of the “Y” being positioned between the big toe and adjacent toe. The strap is secured to the sole with strap retention plugs extending through the flip flop.

FIG. 2 is a cross-sectional view of the attachment of the strap of the PRIOR ART flip flop. More specifically, the sole of the flip flop is formed with a plug bore passing perpendicularly through the sole and leading to a plug receiver sized to closely receive a strap retention plug integrally formed on the end of the strap.

Attachment of the strap to the sole is accomplished by inserting the strap retention plug through the plug bore in the sole in the downward direction. Due to the deformable nature of the rubber sole and the strap retention plug, the size of the plug bore may be much smaller than the retention plug. Once the strap retention plug is passed through the plug bore and through the sole of the flip flop, the strap is then drawn upwards so that the strap retention plug is received in the plug receiver to form a smooth bottom surface of the flip flop.

One challenge with this method of construction is that the typical location of a failure of the flip flop occurs where the strap joins the strap retention plug. This is due in large part to the extraordinary tensional forces exerted on the strap during the ordinary wearing of the flip flop. In other cases, the failure of the flip flop is due to the weakening of the sole adjacent the plug bore where the sole is thinner. In those cases, the strap retention plug will pull through the sole.

In light of the above, it would be advantageous to provide an improvement to the ordinary flip flop which overcomes many of the structural deficiencies of the prior art flip flops, yet is equally if not more comfortable to wear, and equally if not more cost effective to manufacture.

SUMMARY OF THE DRAWINGS

FIG. 1 depicts the upper and lower views of a PRIOR ART flip flop and shows the sole, and the positioning and attachment of the strap;

FIG. 2 is a cross-sectional view of the strap attachment to the sole, showing the strap and strap retention plug, and the plug receiver and the plug bore as formed in the sole;

FIG. 3 is a perspective view of the upper portion of the flip flop of the present invention showing a sole, “Y” shaped a cloth or woven strap terminating at its endpoints with a strap attachment loop passing through the sole, and a perspective view of the lower portion of the flip flop showing the attachment loop passing through strap retention discs which sit flush within disc receivers formed on the underside of the sole;

FIG. 4 is a cross-sectional view of the strap and its attachment to the sole of the present invention, showing the strap fastened to an attachment loop passing through the retention disc, and the retention disc and attachment loop being passed through the disc bore;

FIG. 5 is a cross-sectional view of the strap and its attachment to the sole of the present invention showing the strap fastened to the attachment loop passing through the retention disc, and the retention disc and attachment loop being pulled upwards seating the strap retention disc in the disc receiver formed in the underside of the sole.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 3, the single sole sandal having fabric straps of the present invention is shown in a perspective view. This Figure provides a view of the upper portion of the flip flop and shows a roughly foot-shaped sole. This sole, in a preferred embodiment, is made from Ethylene-vinyl acetate (also known as EVA or sometimes simply as “acetate”) which is the copolymer of ethylene and vinyl acetate. EVA is a polymer that approaches elastomeric materials in softness and flexibility, yet can be processed like other thermoplastics thus providing for use of well known injection molding and production techniques. The EVA material has good clarity and gloss, heat and moisture barrier properties, low-temperature toughness, is stress and crack resistant, and is resistant to UV radiation, and is thus ideal for outdoor use by providing a lightweight and durable sole.

The present invention also includes a “Y” shaped strap shaped so that one leg of the strap passes between the big toe and adjacent toe of the wearer, and the other two legs of the strap pass to the sides of the foot and attach near the heel. In a preferred embodiment, the strap is made from a cloth or woven material to provide for increased comfort and strength. The cloth or woven strap terminates at its endpoints with a strap attachment loop. The strap attachment loop is fixedly attached, such as by sewing, to the ends of the strap, and captures a strap retention disc in the loop. Once the strap attachment loop is attached to the strap, the strap retention disc is passed through the sole from the upper surface through to the bottom. Once the strap retention disc has been passed through the sole, the strap retention discs sits flush within disc receivers formed on the underside of the sole.

From FIG. 4, a cross-sectional view of the strap and its attachment to the sole of the present invention is shown and illustrates the strap securely fastened to an attachment loop. The attachment loop passes through the retention disc to secure the retention disc to the strap. As shown, the retention disc and attachment loop are passed downward in the direction of the arrow through the disc bore formed in the sole. The sole is sufficiently pliable to accommodate the passage of the retention disc through the sole without damage, and once past, the sole returns to its original shape.

Moving along to FIG. 5, a cross-sectional view of the strap and its attachment to the sole of the present invention shows the strap fastened to the attachment loop passing through the retention disc. The retention disc and attachment loop are then pulled upwards in the direction of the arrow towards the sole, seating the strap retention disc in the disc receiver formed in the underside of the sole.

The single sole sandal having fabric straps of the present invention as shown has a number of advantages over the prior art. For instance, the present invention provides for a more durable sandal as the straps are less likely to fail due the ordinary stresses of wear because the high-strength strap attachment loop and high-strength retention disc are far stronger than the molded strap retention plug. Moreover, because the strap retention disc is much thinner than the art strap retention plug, the depth of the disc receiver formed in the sole is much thinner than the plug receiver. As a result, the strength of the sole is not jeopardized.

Another advantage of the present invention is the attachment of a cloth strap to a single sole sandal. For instance, previously, in order to attach a cloth strap to a foam-soled sandal, the sandal would have to be made with a two-part sandal where the cloth strap would insert through a slit in the upper layer of the sandal, and be captured between the upper and lower layer using an adhesive. The present invention, however, provides for the easy attachment of a cloth strap to a single-layered sole.

It is to be understood that the single sole sandal having fabric straps of the present invention as shown is merely exemplary of a preferred embodiment and that no limitations are implied except those specifically stated. It is to be appreciated that the various features and cooperation of those features discussed above are to be extended to similar structures and methods of manufacturing as is known in the art.

Claims

1. A single sole sandal, comprising:

a Y-shaped strap having three legs each having an end;

a sole formed of a single material and formed with an aperture to receive each said end;

a strap retention disc having a diameter and attached to said end;

wherein said diameter of said strap retention disc is larger than said aperture.