A flip-flop includes a sole and a strap unit. The strap unit includes a thong portion, and first and second strap portions, and is made by the steps of: providing superposed first and second layers of warp threads; inserting a first weft thread through sheds formed in the first layer of warp threads so as to weave the first strap portion; inserting a second weft thread through sheds formed in the second layer of warp threads so as to weave the second strap portion; and inserting the first and second weft threads through sheds which are cooperatively formed by the superposed first and second layers of warp threads so as to weave the thong portion.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to footwear, more particularly to a flip-flop.

2. Description of the Related Art

FIG. 1shows a conventional flip-flop including a sole11and a strap unit12. The strap unit12includes two woven straps121each of which has a first end portion1210that is secured to a left or right side of a middle part of the sole11, and a second end portion1211that is stitched to the second end portion1211of the other one of the woven straps121to form a stitched thong122. The stitched thong122is secured to a front part of the sole11and is disposed to fit between the first and second toes of a wearer's foot.

The strap unit12is made by two independent processes, i.e., separately weaving the two woven straps121, and stitching the woven straps121to form the stitched thong122. Thus, the strap unit12of the conventional flip-flop is produced with a relatively low efficiency and at a relatively high cost.

Although the strap unit12can be formed by a single process using a plastic material, it may give the wearer an unpleasant tactile feeling and may have a weaker stretch strength compared with the strap unit12made by weaving/stitching processes.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide a flip-flop that can be made in a single continuous process using a weaving method, especially a double weft needles method.

According to this invention, a flip-flop includes a sole for a wearer's foot to rest thereon, and a strap unit. The sole has upper and lower surfaces, and the upper surface includes front, middle and rear regions. The strap unit includes a thong portion which has a first thong end secured to the front region, and a second thong end opposite to the first thong end, and first and second strap portions extending rearwardly from the second thong end to terminate at and be secured to left and right sides of the middle region, respectively. The strap unit is made by the steps of:

(a) providing superposed first and second layers of warp threads;

(b) inserting a first weft thread through sheds formed in the first layer of warp threads so as to weave the first strap portion along a first lengthwise line such that one of first leading and trailing ends of the first strap portion has a first oblique boundary which is at an oblique angle to the first lengthwise line;

(c) inserting a second weft thread through sheds formed in the second layer of warp threads so as to weave the second strap portion along a second lengthwise line such that one of second leading and trailing ends of the second strap portion has a second oblique boundary which is at an oblique angle to the second lengthwise line, and which joins the first oblique boundary to cooperatively define the second thong end at which the first and second lengthwise lines meet; and

(d) inserting the first and second weft threads through sheds which are cooperatively formed by the superposed first and second layers of warp threads so as to weave the thong portion along a direction from one of the first and second thong ends to the other one of the first and second thong ends.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before the present invention is described in greater detail, it should be noted herein that like elements are denoted by the same reference numerals throughout the disclosure.

Referring toFIGS. 2 to 4, a first preferred embodiment of a flip-flop according to this invention is shown to include a strap unit2and a sole3for a wearer's foot to rest thereon. The sole3has upper and lower surfaces301,302. The upper surface301includes front, middle and rear regions31,32,33.

The strap unit2includes first and second extension portions21,22, a thong portion23, and first and second strap portions24,25. The thong portion23has a first thong end231secured to the front region31, and a second thong end232opposite to the first thong end231in a lengthwise direction of the strap unit2. The first strap portion24extends rearwardly from the second thong end232through the sole3at a left side of the middle region32to terminate at a distal end241which is secured to the lower surface302of the sole3. The second strap portion25extends rearwardly from the second thong end232through the sole3at a right side of the middle region32to terminate at a distal end251which is secured to the lower surface302of the sole3. The first and second extension portions21,22extend downwardly from the first thong end231through the sole3at the front region31and are secured to the lower surface302of the sole3. A first lengthwise line242of the first strap portion24and a second lengthwise line252of the second strap portion25cooperatively define an included angle θ that ranges between 30° and 90°.

With reference toFIGS. 5 and 6, the strap unit2shown inFIGS. 2 and 3is made by a double weft needles method using a needle loom6which is preferably a computerized jacquard loom. Steps (a) to (f) are implemented for continuously weaving a plurality of the strap units2. It should be noted that the sequence of steps (a) to (f) is limited to that disclosed herein or shown inFIG. 5, and may vary depending on the weaving direction of the strap units2. That is, although in the embodiment shown inFIG. 5, each strap unit2is woven by weaving, in order, the first and second extension portions21,22, the thong portion23, and the first and second strap portions24,25, it may be woven in an opposite order.

In step (a), superposed first and second layers of warp threads61,62, which can be made by any known method, are arranged in the needle loom6.

Instep (b), a first weft thread63is inserted through sheds formed in the first layer of warp threads61using a first weft needle65so as to weave the first strap portion24along the first lengthwise line242from a first leading end243to a first trailing end244such that one of the first leading and trailing ends243,244has a first oblique boundary245which is at an oblique angle to the first lengthwise line242. In this embodiment, the first leading end243has the first oblique boundary245.

In step (c), a second weft thread64is inserted through sheds formed in the second layer of warp threads62using a second weft needle66so as to weave the second strap portion25along the second lengthwise line252from a second leading end253to a second trailing end254such that one of the second leading and trailing ends253,254has a second oblique boundary255which is at an oblique angle to the second lengthwise line252, and which joins the first oblique boundary245to cooperatively define the second thong end232at which the first and second lengthwise lines242,252meet. In this embodiment, the second leading end253has the second oblique boundary255. Steps (b) and (c) are simultaneously implemented for weaving both the first and second strap portions24,25.

In step (d), the first and second weft threads63,64which are respectively guided by the first and second weft needles65,66are inserted through sheds which are cooperatively formed by the superposed first and second layers of warp threads61,62so as to weave the thong portion23along a direction from one of the first and second thong ends231,232to the other one of the first and second thong ends231,232. In this embodiment, the thong portion23is woven along the direction from the first thong end231to the second thong end232.

In step (e), the first weft thread63is inserted through sheds formed in the first layer of warp threads61by the first weft needle65so as to weave the first extension portion21from the first thong end231or the first trailing end244of the first strap portion24of a preceding one of the strap units2. In this embodiment, the first extension portion21is woven from the first trailing end244of the first strap portion24of the preceding one of the strap units2. (seeFIG. 5).

In step (f), the second weft thread64is inserted through sheds formed in the second layer of warp threads62by the second weft needle66so as to weave the second extension portion22from the first thong end231or the second trailing end254of the second strap portion25of a preceding one of the strap units2. In this embodiment, the second extension portion22is woven from the second trailing end254of the second strap portion25of the preceding one of the strap units2(seeFIG. 5).

The plurality of the strap units2can be successively and efficiently produced using the needle loom6, and the patterns and the shapes of the strip unit2can be varied according to design requirement. For example, as shown inFIG. 3, each of the first and second strap portions24,25may have an increased width section/segment that gradually increases in width away from the second thong end232, and an equal-width section/segment extending from increased width section/segment toward the respective distal end241(251).

In this embodiment, each of the warp threads61,62and the first and second weft threads63,64is selected from a terylene yarn (which may be a high-tension yarn or a low-tension yarn), a nylon yarn (which may be a high-tension yarn or a low-tension yarn), a metallic yarn, etc.

FIG. 7shows a strap unit2used in a second preferred embodiment of a flip-flop according to this invention. In this embodiment, the strap unit2further includes two reinforcing pieces26disposed on the first and second strap portions24,25, respectively, and extending along the first and second lengthwise lines242,252, respectively. With the provision of the reinforcing pieces26, the structure of the first and second strap portions24,25can be enhanced.