METHOD FOR MANUFACTURING A SANDAL HAVING CUSTOMISED TOE THONG LOCATION

Abstract

A method for manufacturing a sandal, wherein the toe thong location of said sandal is customised for a wearer. For a particular wearer, the optimal location of the toe thong of the sandal may be determined by applying a computer algorithm, which takes into account foot data of the wearer, which foot data may be obtained from image/video capture technology. The method makes use of a custom toe thong insert, which is embedded within the sole of the sandal. The custom toe thong insert is configured to receive and securely engage with a fastener attached to the toe thong and foot strap, such that the toe thong will be positioned at or proximate to the optimal location for the particular wearer. Also disclosed herein is a sandal with a customised toe thong location that is made in accordance with the above-described method.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority from, and incorporates by reference, the entire disclosures of U.S. Provisional Patent Application No. 62/356,727, filed Jun. 30, 2016 and U.S. Provisional Patent Application No. 62/475,099, filed Mar. 22, 2017.

FIELD OF THE INVENTION

The present invention relates to the field of footwear. More specifically, the present invention relates to the field of sandals or flip-flops having a toe thong location that is customised for a wearer, and a method of manufacturing same.

BACKGROUND

Sandals or flip-flops (generally referred to herein as sandals) are a popular form of footwear. They are most commonly worn in warm weather, since they allow more ventilation than most other forms of footwear. They are also often selected for wear for various other reasons, for example because they are light, casual in style, convenient to put on, easy to pack, waterproof, etc. Sandals are generally viewed as low cost items; from a manufacturing perspective, they tend to be of simple construction, and tend to be made from low-cost materials such as foam (e.g. ethylene-vinyl acetate foam) and plastic. Like most footwear, a standard construction is adopted with respect to the structural aspects of a pair of sandals, save with adjustments based upon the wearer's actual foot size. From a commercial standpoint, it is not generally contemplated that sandals could be customized for a particular wearer (also sometimes referred to herein as a “user”), especially given sandals' low cost and simple construction. However, given that there can be some considerable variety in terms of shapes, features, and sizes of people's feet, many wearers will find that the standard construction does not suit them even if the foot-size itself is the correct one. This can result in the sandals being ill-fitting or uncomfortable for a specific wearer (which will be exacerbated if the wearer does quite a bit of walking in the sandals and/or plans to wear them often).

Sandals are often provided with a toe thong. A toe thong (sometimes also called a “toe post”), as used herein, refers to a resilient member that is generally connected to the foot strap of the sandal, and to the sole of the sandal. The base of the toe thong is generally located on the upper sole of the sandal and is proximate to, when the sandal is worn by a wearer, the space between the neck of the wearer's big toe and the neck of the wearer's second toe. When the wearer is wearing and walking in such sandal, the toe thong helps to maintain the position of the sandal relative to the wearer's foot and helps prevent the sandal from falling off the wearer's foot. Further, the wearer may, when necessary, grip the toe thong between his big toe and second toe, so that the sandal does not easily fall off the wearer's foot. In the case of conventional sandals, the toe thong is located at a standard “one-position-fits-all” location. However, given that there can be some considerable variety in terms of shapes, features, and sizes of people's feet, a standard toe thong location can, in many cases, cause discomfort and/or an improper fit.

Accordingly, there would be advantages in providing a sandal wherein the location of the toe thong is customised for a particular wearer. By taking into account various wearer-specific parameters such as size, shape and/or profile of a wearer's foot; shape, size and location of the wearer's toes, and other related features of the foot (thickness, etc.), one would be able to determine a preferred location for a toe thong on the sandal for that wearer, and thus produce a sandal that is more customized for that wearer, thus improving the wearer's comfort and fit.

It is contemplated that one could employ various inputs to facilitate determining a preferred toe thong location. For example, this may be achieved via use of 2-dimensional (2-D) or 3-dimensional (3-D) imaging or via use of a computer vision algorithm based upon 2-D or 3-D foot data, e.g. using a single photograph of the wearer's foot, several photos of the wearer's foot taken from different angles, or a video of the wearer's foot taken from various angles. It is contemplated that the 2-D or 3-D foot data could be self-generated by a wearer (i.e. by the wearer photographing/capturing his own feet), generated by a device specifically configured for such purpose (e.g. a 2-D/3-D image camera at a kiosk); or generated by a third-party service provider; or provided from the wearer's medical records (e.g. from a podiatrist/chiropodist, including x-ray data). Such a sandal, having a customised toe thong location, could significantly improve a wearer's comfort and fit.

U.S. patent application Ser. No. 15/309,406, filed Dec. 23, 2016, entitled “Generation of 3D-Printed Custom Wearables”, discloses a possible approach for generating custom wearables based upon inputs involving scanning (a body part of the wearer), image processing, machine learning, computer vision, and/or user input, which is incorporated in its entirety herein by reference.

Furthermore, being able to provide such a customized sandal may allow greater options and flexibility regarding the design of sandals; for example, it may be possible to use stiffer/stronger materials for the toe thong than would otherwise be possible, because of the improved fit and comfort.

BRIEF SUMMARY OF THE INVENTION

Disclosed herein is a method for manufacturing a sandal, wherein the toe thong location may be customised for a wearer. Also disclosed herein is a sandal with a customised toe thong location that is made in accordance with the above-described method.

In accordance with an aspect of the present invention, disclosed herein is a method for manufacturing a sandal having a toe thong location that is customised for a wearer, wherein the sandal comprises a foot strap, a toe thong connected to the foot strap, and a sole, wherein the toe thong is configured with a fastener, and wherein the sole comprises an upper sole and a midsole, the method comprising: (i) receiving foot data for the wearer; (ii) determining for the wearer, an optimal toe thong position in respect of a given sandal, based upon the foot data for the wearer; (iii) providing a custom toe thong insert having a plurality of fastener-engagement holes for engagement with the fastener; (iv) embedding the custom toe thong insert within the midsole of the sandal at an insert location; (v) determining an optimal fastener-engagement hole of the plurality of fastener-engagement holes, taking into account the optimal toe thong position; (vi) providing an orifice in the upper sole of the sandal, proximate to the optimal toe thong position; and (vii) inserting the fastener, through the orifice in the upper sole of the sandal, and engaging the fastener with the optimal fastener-engagement hole, thereby fastening the fastener to the custom toe thong insert.

In accordance with another aspect of the present invention, disclosed herein is a method for manufacturing a sandal having a toe thong location that is customised for a wearer or user, wherein the sandal comprises a foot strap, a toe thong connected to the foot strap, and a sole (the sole comprising an upper sole, a midsole and an outsole), the method comprising: (i) acquiring foot data for said wearer; (ii) determining for the wearer, an optimal toe thong position in respect of a given sandal, based upon the foot data for the wearer; (iii) determining a customised location for a hole to be applied to a custom toe thong insert, wherein the custom toe insert is to be embedded in the sandal in an insert location, taking into account the insert location and the optimal toe thong position; (iv) providing a custom toe thong insert with a hole at the customised location; (v) embedding the custom toe thong insert into the insert location within the midsole of the sandal; (vi) providing an orifice in the upper sole of the sandal, proximate to the optimal toe thong position; and (vii) inserting a fastener, attached to the toe thong at one end, through the orifice in the upper sole of the sandal and into the hole of the custom toe thong insert and fastening it to the custom toe thong insert, to form a sandal with a customised toe thong location.

In accordance with another aspect, also disclosed herein is a sandal made using the foregoing methods.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention are described below with reference to the accompanying drawings in which:

FIG. 1 is a top plan view of a sandal provided with a custom toe thong insert.

FIG. 2 is a top plan view of a sandal provided with an alternative embodiment of the custom toe thong insert.

FIG. 3 is a diagram illustrating a custom toe thong insert, and the different positions where the toe thong may engage therewith.

FIG. 4 is a diagram illustrating an alternative embodiment of a custom toe thong insert.

FIG. 5 is a sectional view of the sandal with a custom toe thong insert of FIG. 1, taken along the A-A axis.

FIG. 6 is a sectional view of the sandal with a custom toe thong insert of FIG. 2, taken along the B-B axis.

FIG. 7 is a perspective view illustrating an alternative embodiment of the custom toe thong insert and the fastener for engaging therewith.

FIG. 8 illustrates the custom toe thong insert and the fastener for engagement therewith, and a toe thong key.

FIG. 9 illustrates alternative versions of the toe thong key.

FIG. 10 is a flowchart which outlines an exemplary method for manufacturing a sandal with a customised toe thong location.

FIG. 11 is a flowchart which outlines an alternative method for manufacturing a sandal with a customised toe thong location.

DETAILED DESCRIPTION OF THE INVENTION

The present invention now will be described more fully hereinafter with reference to the accompanying drawing(s), which form a part hereof, and which show, by way of illustration, exemplary embodiments by which the invention may be practiced. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The following detailed description is, therefore, not to be taken in a limiting sense.

Referring to FIG. 1, a top plan view of a sandal 10 with a customised toe thong location is shown. For ease of discussion, the invention is illustrated herein with reference to customisation of a single sandal in accordance with one foot of a wearer; naturally, in practice, a pair of customised sandals would be manufactured, taking into account both feet of the wearer. The sandal 10 has a sole 12, a foot strap 16 and a toe thong 25. The sole 12 generally comprises an upper sole 13 (as visible in FIG. 1), a midsole 37 and an outsole 40. The foot strap 16 is generally attached to the sole 12 at a location proximate to the outstep or lateral side of the sandal (sometimes referred to herein as the outstep side 19) of the sandal 10, and at a location proximate to the instep or medial side (sometimes referred to herein as the instep side 22) of the sandal 10. The foot strap 16 is also attached to the toe thong 25 (Optionally, the toe thong 25 and the foot strap 16 may be incorporated together). A custom toe thong insert 31 is configured with at least one hole 34. The custom toe thong insert 31 is shown in FIG. 1, so that its position can be shown for reference purposes; however, it should be understood that the custom toe thong insert 31 is actually generally positioned/embedded under the upper sole 13 (and thus would not generally be visible from a top plan view of the sandal 10).

The toe thong 25 is provided with a fastener 26 located at the end of the toe thong 25 distal to where the toe thong 25 is attached to the foot strap 16. The fastener 26 may be in the form of a male member which is inserted through a hole in the upper sole 13 and which is configured to be inserted through the hole/compartment 34 to securely engage the custom toe thong insert 31. In one preferred embodiment, the fastener 26 may be in the form of a rotatable plug, which has a larger profile in one direction and a smaller profile in another direction. In one configuration, the plug presents its smaller profile to the hole 34 so that it can be inserted into the hole 34; when the plug is rotated into a “locked” position, it presents its larger profile to the hole 34, thereby securing the fastener 26 (and the attached toe thong 25) to the hole 34 (see also FIG. 7). In another example, the fastener 26 may be in the form of a generally circular plug, which is configured such that it has a greater profile at its back end than at its forward end, so that the plug can be inserted into the hole 34 in a forward direction and “snapped” in place, but is relatively difficult to pull out from the hole in the backward direction once installed. FIG. 2 is a top plan view of a sandal 10 provided with an alternative example of the custom toe thong insert 32 (also shown in FIG. 4). In this case, the custom toe thong insert 32 is provided with a plurality of openings (three, as illustrated), which are provided with barbs. The fastener 26 is provided with mating barbs that lock into place, once pushed in, and with the optional ability to be removed when pressed and pulled in a particular direction—in a similar fashion to zip-ties or zap-straps. Other types of fasteners that are known in the art may also be used to engage and/or secure the toe thong 25 to the sole 12.

As mentioned above, the custom toe thong insert 31, and the alternative embodiment of the custom toe thong insert 32, are shown in FIG. 1 and FIG. 2, respectively, in order to illustrate their actual location relative to the toe thong 25; it should be noted that when the sandal 10 is fully assembled, the custom toe thong insert 31 (32 in the case of the alternative embodiment of FIG. 2) is embedded within the sole 12, under the upper sole 13, and is thus not actually visible.

FIG. 3 illustrates the custom toe thong insert 31, and how the actual location of the hole 34 may be placed in one of multiple locations (e.g. 34A-34E). Although in the example in FIG. 3, the custom toe thong insert 31 is provided with 5 different positions for the hole 34, all of which are offset along the x-direction (generally horizontal), it should be understood that the location of the hole 34 may be offset in the y-direction (generally vertical), or in both the x and y directions. As described below, it is contemplated that, in the manufacturing process for the sandals 10, the custom toe thong insert 31 would preferably be a component that can be fabricated using 3-D printing techniques; as such, there is considerable variation and flexibility in terms of the precise location of the hole 34.

FIG. 4 is a diagram illustrating an alternative example of the custom toe thong insert 32. The custom toe thong insert 32 is shown with three openings, which correspond to possible locations for a hole (35A-35C) at which location the fastener 26 may be securely engaged. In this embodiment, each opening is provided with engaging barbs, and the fastener 26 is provided with mating barbs (not shown in FIG. 4, but shown for example in FIG. 6).

FIG. 5 is a sectional view of the sandal 10 in FIG. 1, taken along the axis A-A. This view more clearly illustrates how the custom toe thong insert 31 is embedded within the sole 12, generally in the midsole layer 37.

FIG. 6 is a sectional view of the sandal 10, with a custom toe thong insert 32 of FIG. 2, taken along the B-B axis.

FIG. 7 is a diagram more clearly illustrating a preferred embodiment of the custom toe thong insert 31, and the fastener 26 adapted to engage with said custom toe thong insert 31. The fastener 26 is shown with a rotatable barrel 35 to which the base 28 of the toe thong 25 is attached. The fastener 26 may be inserted into the appropriate hole 34 (having available positions 1-3, as shown), determined to be most suitable for the particular wearer, and rotated into a secured or “locked” position.

For a sandal 10 for which the toe thong location may be customized for a wearer's feet, as a further optional feature, the wearer may be provided with a toe thong key 55 as shown in FIG. 8. In such embodiment, the toe thong key 55 may be configured to specifically engage with the rotatable barrel 55, so that it can be turned. The rotatable barrel 55 may be configured so that it will not turn unless it is engaged with the right profile/dimension of key, as provided by the toe thong key 55. In other words, it is contemplated that a wearer would not readily be able to adjust/disengage the toe thong 25 from the sole of the sandal (e.g. using her fingers) without the toe thong key 55. The application of the toe thong key 55 enables the fastener 26, which is securely engaged with hole 34 (e.g. position 2), to be unlocked and disengaged from the hole 34. The toe thong key can be provided in various forms, as shown in FIG. 9. For example, it can be a separate tool that is provided with each sandal purchase, or it may be integrated with or attached to the toe thong itself. Alternatively, the toe thong key may be integrated with one of the detachable side straps of the foot strap 16 as toe thong key 64.

The provision of a toe thong key 55 may be used to allow a wearer to exchange one foot strap with another foot strap (e.g. either to replace an old foot strap or to change the design of the sandal's foot strap, or even in the event that a wearer might decide to make her own adjustments to the original toe thong location set during manufacturing of the sandal 10).

FIG. 10 is a flowchart which outlines an exemplary method for manufacturing a sandal 10 with a customised toe thong location, as generally previously described in FIG. 1. At step 2, data regarding the wearer's foot/feet (sometimes referred to herein as foot data) is obtained (step 2).

This foot data is generally in a digital or digitizable format. This foot data can take various forms. (U.S. patent application Ser. No. 15/309,406, filed Dec. 23, 2016, entitled “Generation of 3D-Printed Custom Wearables”, discloses a possible approach for generating custom wearables based upon inputs involving scanning a body part of the wearer, image processing, machine learning, computer vision, and/or user input). This can simply be a photo or such other image capture of the wearer's bare foot (this could be a photo of the top or bottom of the wearer's foot) that is taken using an image or video capture device or such other computer vision technology, such as a camera, smartphone or such other dedicated equipment. More usefully, the foot data may comprise several photos taken of the wearer's foot from different views/angles. The wearer may be guided to take specific views of the wearer's foot (e.g. a top plan view, a bottom view, a side or front view, etc.). Optionally, the wearer may also be directed to take a photo or photos that include a standard or reference object, in order to facilitate determining the size of the wearer's feet. In a preferred embodiment, a dedicated downloadable software application, mobile app or application program interface (“API”) may be provided to the wearer and installed on the wearer's mobile device (such as a smartphone) in order to instruct and guide the wearer in taking the appropriate views of his foot.

It is also contemplated, however, that suitable foot data may be obtained by the wearer taking multiple photos of his foot from arbitrary views/angles provided these are sufficiently different to provide sufficient detail regarding the 2-dimensional or 3-dimensional geometry, as the case may be, of the wearer's foot; the processing software can be configured to compile the wearer's foot data from such photos, although this introduces additional complexity from a processing standpoint compared to using specified views.

Alternatively, the foot data may be obtained from a video that is taken of the wearer's foot, again preferably from different views, e.g. by the wearer panning the video/image capture device around the foot. In a further alternative, the historical foot data of the wearer's feet (such as medical records from a podiatrist or chiropodist, or other medical professional, etc. or previously obtained photos/videos/x-rays) may also be used as the input for the wearer's foot data.

Once the foot data is obtained, the optimal toe thong position for the wearer in respect of a given sandal is determined using a computer algorithm based on the wearer foot data (step 3). This determination will take into account the shape, size and thickness of the wearer's foot; the size, shape and thickness of the wearer's toes (particularly of the wearer's big toe and second toe); and the natural spacing between the wearer's big toe and second toe, etc. Optionally, this determination can also take into account one or more of the following, namely: (a) the size of the toe thong for the given sandal design; (b) the shape of the toe thong for the given sandal design; (c) the particular design of the given sandal; and (d) the type of material to be used for the toe thong. By way of example, where the design of a particular sandal is such that it has a particularly small toe thong, it may be desirable to make an adjustment to the location of the toe thong away from the actual optimal location, to provide the wearer with slightly better grip for the sandal.

The customised location for a hole (of a specified size) 34 to be applied to a custom toe thong insert 31 is determined (step 4), taking into account where the custom toe thong insert 31 is to be embedded in the sole 12 of the particular sandal 10 (sometimes referred to herein as the “insert location”), and the optimal toe thong position determined from step 3. This allows for the hole 34, when the custom toe thong insert 31 in embedded in the sole 12 of the sandal in its predetermined location, to generally correspond to the optimal toe thong position for the wearer.

A custom toe thong insert 31 with a hole (of a specified size) 34 at the customised location is provided (step 5). The hole 34 is generally round, i.e. circular or oval, although other shapes are possible depending on the form of the fastener 26 that is used to engage with the hole 34 and custom toe thong insert 31. The appropriate size of hole 34 may also depend on the type of fastener 26 used. As shown in FIG. 3, the hole 34 for the custom toe thong insert 31 is illustrated as optionally being located in one of 5 different locations 34A-34E on the custom toe thong insert 31. For the sake of illustration, it can be determined which of these positions corresponds to (or, if this is not possible, best approximates to) the customised location and to the optimal toe thong position. In the example shown in FIG. 1, the custom toe thong insert 31 is shown with the toe thong 25 inserted into the hole position corresponding to location 34C.

During the assembly/manufacturing of the particular sandal 10 (which generally comprises a sole 12 or sandal bed; a foot strap 16 attached to the sole 12 at a instep side 22 and an outstep side 19; and a toe thong 25 attached to the foot strap 16), the appropriate custom toe thong insert 31 is placed in its predetermined position and embedded within the sole 12 or sandal bed (step 6). As previously illustrated in FIG. 5, the custom toe thong insert 31 is preferably embedded in the midsole 37 of the sole 12 of the sandal 10. Although not specifically shown, the midsole 37 may be fabricated with a space for receiving the custom toe thong insert 31, and corresponding to the predetermined position, in order to facilitate the assembly of the sandal 10 and to ensure the correct positioning of the custom toe thong insert 31 during manufacture/assembly of the sandal.

Accordingly, the hole 34 is positioned at or proximate to where the base 28 of the toe thong 25 should be located for the wearer.

An orifice is made in the upper sole 13 of the sandal 10, proximate to where the base 28 of the toe thong 25 is to be positioned (step 7)(this also corresponds to the location where the hole 34 in the custom toe thong insert 31 would be located in the assembled sandal 10).

A fastener 26 is provided at the end of the toe thong 25 distal to where the toe thong 25 is attached to the foot strap 16. The fastener 26 is inserted through the orifice in the upper sole 13 of the sandal 10, and into the hole 34 of the custom toe thong insert 31, and securely fastened to the custom toe thong insert 31 (step 8). The base 28 of the toe thong 25 is accordingly positioned at a location corresponding to (or proximate to) the optimal toe thong position.

Assembly of the sandal 10 is completed, as may be necessary. In this fashion, a sandal (or more accurately, one foot of a pair of sandals) with a customised toe thong location is manufactured for the wearer. It is contemplated that in the above described process, it is possible to dispense with step 7 by inserting the fastener 26 directly through the upper sole 13 without first making an orifice therein.

FIG. 11 is a flowchart which outlines a method for manufacturing a sandal 10 with a customised toe thong location, containing the alternative embodiment of the custom toe thong insert 32, as previously described in FIGS. 2 and 4. Steps 1-5 of FIG. 8 are the same as for FIG. 7. In step 6, the custom toe thong insert 32 is placed in its predetermined position and embedded within the sole 12 or sandal bed. In this particular case, the custom toe thong insert 32 is provided with a hole or compartment (at location 35A-C), which is configured to receive a fastener 26 for locking engagement therewith. As previously illustrated in FIG. 6, the custom toe thong insert 32 is preferably embedded in the midsole 37 of the sole 12 of the sandal 10. Although not specifically shown, the midsole 37 may be fabricated with a space for receiving the custom toe thong insert 32 and corresponding to the predetermined position, in order to facilitate the assembly of the sandal 10 and to ensure the correct positioning of the custom toe thong insert 32 during manufacture/assembly of the sandal.

An orifice is punched through the upper sole 13 of the sandal 10, which is proximate to the optimal toe thong position (step 7). This orifice allows access to the appropriate hole or compartment 35 of the custom toe thong insert 32.

Next, the fastener 26 (for example, in the form of a zip-tie or zap-strap) attached to the toe thong 25 at one end thereof, is inserted through the orifice in the upper sole 13 of the sandal, into the hole or compartment of the custom toe thong insert 32 and fastened thereto, to form a sandal 10 with a customised toe thong location.

Claims

1. A method for manufacturing a sandal having a toe thong location that is customised for a wearer, wherein the sandal comprises a foot strap, a toe thong connected to the foot strap, and a sole, wherein the toe thong is configured with a fastener, and wherein the sole comprises an upper sole and a midsole, the method comprising:

(i) receiving foot data for said wearer;

(ii) determining for the wearer, an optimal toe thong position in respect of a given sandal, based upon the foot data for the wearer;

(iii) providing a custom toe thong insert having a plurality of fastener-engagement holes for engagement with the fastener;

(iv) embedding the custom toe thong insert within the midsole of the sandal at an insert location;

(v) determining an optimal fastener-engagement hole of the plurality of fastener-engagement holes, taking into account the optimal toe thong position;

(vi) providing an orifice in the upper sole of the sandal, proximate to the optimal toe thong position; and

(vii) inserting the fastener, through the orifice in the upper sole of the sandal, and engaging the fastener with the optimal fastener-engagement hole, thereby fastening the fastener to the custom toe thong insert.

2. The method of claim 1, wherein the foot data of the wearer is received through an application programming interface.

3. The method of claim 1, wherein the foot data of the wearer is compiled from one or more of 2-Dimensional imaging data, 3-Dimensional imaging data, a single photo, multiple photos, and a video.

4. The method of claim 1, wherein the foot data of the wearer is captured through one of a smartphone or a kiosk camera.

5. The method of claim 1, wherein the fastener and the optimal fastener-engagement hole are configured for locking engagement with each other.

6. The method of claim 5, wherein the fastener and optimal fastener-engagement hole are disengageable through use of a toe thong key.

7. The method of claim 1, wherein the step of receiving foot data for said wearer, is from previously stored foot data of said wearer.

8. The method of claim 1, wherein the step of determining an optimal toe thong position in respect of a given sandal is based upon the foot data for the wearer, and at least one of: the size of the toe thong for the sandal; the shape of the toe thong for the sandal; the design of the sandal; and the type of material from which the toe thong is constructed.

9. A sandal having a toe thong location that is customised for a wearer, made in accordance with the method of claim 1.

10. The sandal of claim 9, wherein the fastener and the optimal fastener-engagement hole are configured for locking engagement with each other.

11. The sandal of claim 10, wherein the fastener and optimal fastener-engagement hole are disengageable through use of a toe thong key.