US20060288610A1

US20060288610A1 - Convertible sandal

Info

Publication number: US20060288610A1
Application number: US11/134,842
Authority: US
Inventors: Daniel Laska; Nicholas Staub
Original assignee: Columbia Sportswear North America Inc
Current assignee: Columbia Sportswear North America Inc
Priority date: 2004-05-14
Filing date: 2005-05-19
Publication date: 2006-12-28
Also published as: WO2007102833A1

Abstract

A convertible sandal comprises a vamp extending over a forefoot portion of the wearer's foot and first and second connectors located along respective medial and lateral sides of the vamp adjacent a rear margin of the vamp. A strap is secured to the connectors and movable selectively between a first position, in which the strap extends behind a heel of the wearer's foot, and a second position, in which the strap extends over the wearer's forefoot. The connectors may include elongated eyelets through which first and second end sections of the strap are threaded and then folded back against the strap for securing the strap to the connectors. In some embodiments a holder is provided for securing the straps across the forefoot or for connecting the sandal to a second sandal or another item using the strap.

Description

RELATED APPLICATIONS

This application is a continuation-in-part and claims the benefit under 35 U.S.C. §120 of U.S. patent application Ser. No. 10/846,404, filed May 14, 2004, which is incorporated herein by reference.

TECHNICAL FIELD

This application relates to footwear and, in particular, to sandals that are convertible between a slide configuration and a heel-strap configuration.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 3,336,683 of Schellkopf, U.S. Pat. No. 4,461,102 of DeVincentis, U.S. Pat. No. 4,584,782 of Thatcher, and U.S. Pat. No. 5,992,058 of Jneid disclose various shoes having uppers that are convertible between a heel-strap configuration, in which a heel strap wraps around the wearer's heel to secure the shoe in place, and a slide configuration, in which the heel strap is moved clear of the heel for easier donning and removal of the shoe. In some of these shoes, the heel straps are disconnected from the shoes when converting to the slide configuration and must thereafter be stored separately or carried by the wearer (e.g., in the wearer's pocket), subjecting the heel straps to being misplaced or lost. In others, the heel straps are folded forwardly for converting the shoes to the slide configuration, but remain attached to the shoes so that a portion of the straps may awkwardly dangle or press against the user's leg or forefoot. Whether a forwardly-folded heel strap dangles or presses against the foot may depend on the length of the heel strap, the point at which it connects to the shoe, and the shape of the wearer's foot.
U.S. Pat. No. 6,237,249 of Aguerre discloses a sandal having a vamp and an elastic heel strap rotatably connected to the vamp via a pair of pivot mechanisms so that the heel strap can be pivoted between a lowered position about the heel of the wearer's foot and a raised position over the arch of the foot and the vamp. The pivot mechanisms increase the complexity of the sandal construction and are subject to mechanical failure.
The present inventor has recognized a need for an improved sandal that is convertible between a heel-strap configuration and a slide configuration and for methods of converting a sandal between such configurations.

SUMMARY

A convertible sandal according to one embodiment comprises a sole for supporting a wearer's foot and a vamp attached to the sole for extending over a forefoot portion of the wearer's foot. First and second connectors are preferably located along respective medial and lateral sides of the vamp adjacent a rear margin of the vamp. In some embodiments, first and second holders are located along the respective medial and lateral sides of the vamp. A strap may be selectively moved between a first position, in which the strap extends around a heel of the wearer's foot, and a second position, in which the strap extends over the wearer's forefoot. The connectors may include elongated eyelets through which the end sections of the strap are threaded and then folded back against the strap for securing the strap to the connectors.
Additional aspects and advantages will be apparent from the following detailed description of preferred embodiments, which proceeds with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a lateral side perspective view of a sandal in accordance with a first embodiment, shown in a heel-strap configuration; and
FIG. 2 is a lateral side perspective view of the sandal of FIG. 1, shown in a slide configuration. In FIG. 2, the phantom lines extending away from the lateral side of the sandal represent an alternative configuration of the strap in which the strap may be used to secure the sandal to another object. All other broken lines in FIGS. 1-2 represent stitching.
FIG. 3 is a side elevation view of a sandal according to a second embodiment, including a swivel connector for the heel strap;
FIG. 4 is an enlarged front elevation view of the swivel connector of FIG. 3;
FIG. 5 is a cross section view of the swivel connector of FIGS. 3 and 4, taken along lines 5-5 of FIG. 4; and
FIG. 6 is an exploded assembly view of the swivel connector of FIGS. 3-5.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 is a lateral side perspective view of a sandal 10 in accordance with a first embodiment, including a strap 14 shown configured in a first position, in which strap 14 is positioned to fit around a heel of a wearer's foot (foot not illustrated). With reference to FIG. 1, sandal 10 includes a sole 20 for supporting the foot and a vamp 30 for extending over a forefoot portion of the wearer's foot. Vamp 30 extends between a medial margin 34 of sole 20 and a lateral margin 36 of sole 20 to fit over the forefoot and keep sandal 10 on the wearer's foot.
Sole 20 may be made by any of a variety of known methods and materials, such as injection molded resins, sewn leather or synthetic materials, and thermoforming, for example. Vamp 30 is preferably split longitudinally so that it comprises medial and lateral side sections 44 and 46 attached to sole 20 along the respective medial and lateral margins 34 and 36. Medial and lateral side sections 44 and 46 are separated by a split 48 along the top of the wearer's foot where the medial and lateral side sections 44 and 46 are joined together by one or more cinch straps 50. Split 48 may comprise an abutting or overlapping region of or a gap between medial and lateral side sections 44 and 46. In some embodiments laces may be used in place of or in addition to cinch straps 50. In still other embodiments, other devices of joining medial and lateral side sections 44 and 46 may be employed. For example, a section of elastic material may be permanently or removably attached to medial and lateral side sections 44 and 46 to span a gap therebetween. In yet other embodiments, vamp 30 is not split longitudinally.
Vamp 30 is preferably split along its entire length, as shown in FIG. 1. However, in alternative embodiments, vamp 30 is split along only a portion of the length of vamp 30. The resulting split 48 (or partial split) between the medial and lateral side sections 44 and 46 of vamp 30 allow vamp 30 to be adjusted to fit the wearer's foot via adjustment of cinch straps 50 or laces. Split 48 preferably includes a longitudinal component, but may run at a significant angle to the longitudinal axis of the sandal 10. Thus, the phrase “split longitudinally,” as used herein, is meant to encompass both a “full” split 48 running the entire length of vamp 30 and a partial split (not shown) extending longitudinally along only a portion of vamp 30, and is also meant to encompass splits running at an angle relative to the longitudinal axis of sandal 10.
Vamp 30 includes a foot opening 52 sized so that when strap 14 is removed from the heel region, as shown in FIG. 2, sandal 10 functions as a slide, which may allow the wearer to don and remove sandal 10 without using his or her hands. Vamp 30 need not cover the entire forefoot, and may include one or more windows 56 or other openings or holes, to promote breathability and reduce the overall weight of sandal 10, among other possible benefits. In some embodiments (not shown), vamp 30 may extend to the rear end of sole 20 to cup the wearer's heel along the edge of the heel pad. In one embodiment, vamp 30 extends forwardly to the toe end of the sole 20. Thus, the term “vamp,” as used herein, is intended to be construed broadly, to include a wide range of devices of various shapes, sizes, and compositions, which generally extend between the medial and lateral margins 34 and 36 of sole 20 and over the wearer's forefoot for keeping sandal 10 on the wearer's foot. Vamp 30 and sole 20 may be constructed and attached together using any of a variety of conventional methods well known to persons skilled in the art.
Vamp 30 includes first and second connectors 62 and 64 located along respective medial and lateral sides of vamp 30 and generally adjacent a rear margin 68 of vamp 30. Connectors 62 and 64 preferably comprise elongated eyelets formed in respective medial and lateral side sections 44 and 46 of vamp 30 and sized to fit first and second end sections 72 and 74 of strap 30 therethrough, as illustrated in FIG. 1. Complementary sections of hook-and-loop fastener material 80 (FIG. 2) of the type sold under the trademark VELCRO®, for example, are arranged on strap 14 so that one or both of end sections 72 and 74 are held in place when folded back upon strap 14 to thereby detachably connect strap 14 to connectors 62 and 64. The eyelets of connectors 62 and 64 may be lined with grommets or plastic inserts sewn to vamp 30 to reinforce the slots and reduce friction and wear of strap 14. In other embodiments (not shown), connectors 62 and 64 may comprise any of a variety of other devices formed or attached in, on, or to vamp 30, and which cooperate with strap 14 for holding strap 14 in place. Such connection devices may tend to align strap 14 in the heel-strap configuration as in the embodiment of FIG. 1, to prevent strap from flapping along or sliding down the wearer's heel when strap 14 is in the first position. Exemplary connecting devices include plastic or metal buckles, snaps, hooks, and/or small eyelets for receiving laces or hooks attached to strap 14, for example. Thus, connectors 62 and 64 preferably facilitate a simple, strong, durable, and convenient detachable connection between strap 14 and vamp 30.
FIG. 2 is a lateral side perspective view of the sandal 10 of FIG. 1, shown configured in a second position wherein strap 14 is disconnected from connectors 62 and 64 and moved clear of the wearer's heel (heel not illustrated) so that sandal 10 functions as a slide. With reference to FIG. 2, when in the second position, strap 14 may be detachably connected to first and second holders 86 located along the respective medial and sides of vamp 30 (the first holder is hidden in the figures, but is substantially similar to second holder 86). When connected to holders 86, strap 14 extends over the forefoot of the wearer's foot for convenient storage and where strap 14 may be tightened to provide added security. In a preferred embodiment, strap 14 may be contoured to fit best in the second position, when strap 14 is reversed left-to-right relative to the first position, i.e., with first end section 72 connected to second holder 86 along lateral side section 46 of vamp 30 and second end section 74 connected to the first holder along the medial side section 44 of vamp 30. If a central window 90 (FIG. 2) is provided in vamp 30 between first and second holders 86, strap 14 may be cinched down across central window 90 and against a top portion of the wearer's foot to improve the fit of sandal 10.
Holders 86 preferably comprise segments or loops of fabric, sewn to vamp 30 to form keeper loops along the medial and lateral sides of vamp 30. Keeper loops are preferably located along outer side surfaces of vamp 30 (as illustrated), but may alternatively be located along inner side surfaces of vamp 30 (not shown). In other embodiments (not shown), holders 86 may comprise any of a variety of other devices formed or attached in, on, or to vamp 30, and which cooperate with strap 14 for holding strap 14 in place. Such holder devices may tend to align strap 14 relative to vamp 30, to prevent strap 14 from sliding or flapping when in the second position. Exemplary holder devices include plastic or metal buckles, snaps, hooks, and/or small eyelets for receiving laces or hooks attached to strap 14, for example.
Holders 86 may also serve as lash points for connecting a pair of sandals 10 together using a strap 14, as partially illustrated in phantom lines in FIG. 2 (second sandal not shown), to prevent the pair of sandals from becoming separated when not in use. When strap 14 is used to connect together a pair of sandals 10 it may also serve as a convenient carrying strap. In addition, to prevent loss of sandals 10 when not being worn, strap 14 may be used to removably secure sandal 10 to another article, such as a carabiner, a backpack, or a lifeline of a boat. When securing sandal 10 to another article, one of the end sections 72, 74 of strap 14 may be connected to one of the connectors 62, 64 or holders 86, and the other of the end sections 72, 74 may be connected to the other object. The hook-and-loop fastener material 80 of strap 14 may provide a convenient means of removably attaching an end of strap 14 to a lifeline of a boat, for example.
FIG. 3 is a lateral side elevation of a sandal 100 in accordance with a second embodiment. With reference to FIG. 3, sandal 100 includes a strap 114 that is pivotably mounted to vamp 130 of sandal 100 for movement between a first position, shown in phantom lines, in which strap 114 is positioned to extend behind a heel region of a wearer's foot (foot not illustrated); and a second position, shown in solid lines, in which strap 114 is rotated forwardly of the ankle to extend over and across an instep portion of the wearer's forefoot. A swivel connector 162 is attached to a lateral side section 146 of vamp 130 near its rear margin 168; and a second swivel connector is connected to vamp 130 along its medial side and opposite swivel connector 162. An end section 174 of strap 114 is preferably attached to a loop 176 (FIG. 4) of the swivel connector 162 that forms an elongated eyelet 178 (FIG. 4). A second end section opposite end section 174 may be similarly attached to a loop of the second swivel connector. In one embodiment, end section 174 is threaded through eyelet 178 and folded back against a main portion of strap 114 spanning between the end sections thereof, and end section 174 is releasably secured to the main portion of strap 114 (for example, with hook-and-loop fastener material or snaps), thereby securely attaching strap 114 to swivel connector 162. The second end section of strap 114 may be similarly secured to the second swivel connector. In some embodiments the end sections may be threaded through the eyelets of the swivel connectors and folded back on the main portion of strap 114 where they are stitched, glued, or otherwise securely attached to the main portion of the strap 114. Other alternative attachment means may also be used. For example, loop 176 may be omitted and/or strap may be directly adhered to, encapsulated within, otherwise fastened to a swiveling part 194 (FIG. 4) of swivel connector 162. In a preferred embodiment, end section 174 is releasably secured to the main portion of strap 114 via hook-and-loop fastener material, and the second end section is folded back upon and stitched to the main portion of strap 114 along the medial side thereof.
If a releasable attachment device is used, strap 114 may be detached from the swivel connectors 162 and reattached to a holder in a manner similar to that described above with reference to FIGS. 1-2 and holder 186. However, in the embodiment shown in FIG. 3, holders are not provided along the sides of vamp separately of the swivel connectors 162. Rather, when strap 114 is not needed behind the wearer's heel, the swivel connectors 162 and strap 114 are rotated forward to the second position (shown in solid lines) for converting sandal 100 to a slide configuration. Thus, in the embodiment of FIG. 3 the swivel connectors 162 also serve as holders for strap 114, when in the second position.
FIG. 4 is an enlarged front elevation view of swivel connector 162 showing detail of loop 176, which forms elongated eyelet 178. FIG. 5 is an enlarged cross section view of swivel connector 162 taken along line 5-5 of FIG. 4, and FIG. 6 is an exploded assembly view of swivel connector 162. With reference to FIGS. 4-6, swivel connector 162 includes a swiveling part 194 and a grommet part 196 that are snap-fit together, as shown in FIG. 5. Swiveling part 194 includes a main body 198 and an inwardly extending flexible plug portion 202 that has multiple tines 204 with barbed distal ends 206. Tines 204 are preferably arranged in a generally cylindrical configuration to provide a bearing surface for supporting swiveling part 194 within grommet part 196 for facilitating pivoting motion. Grommet part 196 includes a flange 210 that rests against an inner surface (not shown) of vamp 130 so that the thickness of vamp 130 (or a portion thereof) is captured between flange 210 and main body 198 of swiveling part 194. Flange 210 may help secure grommet part 196 to vamp 130 and may further prevent grommet part 196 from being pulled through vamp 130. A surface of flange 210 facing toward the inner surface of vamp and swiveling part 194 may include teeth or other gripping features (not shown) for engaging the material of vamp 130 to prevent flange 210 from rotating relative to vamp 130. When swiveling part 194 and grommet part 196 are secured together through a hole (not shown) in vamp 130, barbed distal ends 206 of tines 204 engage an inwardly radially extending shoulder 212 surrounding a socket 214 of grommet part 196, to thereby prevent swiveling part 194 from being pulled apart from grommet part 196, while allowing rotational motion therebetween. Swiveling part 194 and grommet part 194 may both be formed of injection molded resin, such as a high-impact plastic resin, for example. In other embodiments, swiveling part 194 and grommet part 196 may be formed of metal or other materials.
Many other configurations and fastening arrangements may also be employed for swivel connector 162. For example, in an alternative embodiment (not shown), the plug portion 202 and socket 214 are reversed, so that plug portion 202 is formed as part of grommet part 196 and socket 214 is formed in swiveling part 194. In still other embodiments (not shown), the relative radial positions of the tines may be reversed relative to grommet part 196, so that the barbed distal ends 206 extend radially inwardly to engage an outwardly radially extending shoulder of the grommet part 196.
It will be obvious to those having skill in the art that many other changes may be made to the details of the above-described embodiments without departing from the underlying principles of the invention. The scope of the present invention should, therefore, be determined only by the following claims.

Claims

1. A convertible sandal, comprising:

a sole for supporting a wearer's foot;

a vamp attached to the sole for extending over a forefoot of the wearer's foot between medial and lateral margins of the sole, the vamp including medial and lateral sides proximal of the medial and lateral margins of the sole, respectively, and a rear margin proximal of a heel of the wearer's foot;

first and second connectors supported on the vamp along the respective medial and lateral sides thereof and adjacent the rear margin of the vamp;

first and second holders supported on the vamp along the respective medial and lateral sides thereof; and

a strap including opposing first and second end sections, the strap being movable between a first position, in which the first and second end sections are detachably connected to the first and second connectors and the strap extends around a heel of the wearer's foot, and a second position, in which the first and second end sections are detachably connected to the first and second holders and the strap extends over the forefoot.

2. The convertible sandal of claim 1, wherein at least one of the connectors comprises an eyelet.

3. The convertible sandal of claim 1, wherein each of the first and second connectors includes a swivel connector that facilitates pivoting of the strap between the first and second positions.

4. The convertible sandal of claim 1 in which the first holder is the first connector and the second holder is the second connector.

5. The convertible sandal of claim 2, further comprising complementary sections of hook-and-loop fastener material arranged on the strap for engagement when at least one of the end sections is threaded through the eyelet and folded back upon the strap, thereby detachably connecting the strap to the vamp.

6. The convertible sandal of claim 1, wherein:

the connectors comprise elongated eyelets sized for threading the first and second end sections therethrough; and

the strap includes complementary sections of hook-and-loop fastener material arranged so that the first and second end sections may be threaded through the eyelets of the respective first and second connectors and folded back upon themselves, where they are releasably held in place to detachably secure the strap to the vamp in the first position.

7. The convertible sandal of claim 6, wherein at least one of the holders includes a keeper loop sized to receive one of the first and second end sections of the strap therethrough.

8. The convertible sandal of claim 1, wherein at least one of the holders includes a keeper loop.

9. The convertible sandal of claim 1, wherein the keeper loop is sewn to the vamp.

10. The convertible sandal of claim 1, wherein the vamp is split longitudinally to facilitate adjustment of the vamp to fit the wearer's foot.

11. The convertible sandal of claim 10, further comprising one or more cinch straps or laces, or both, extending between the medial and lateral sides of the vamp for tightening the vamp to fit the wearer's foot.

12. A convertible sandal, comprising:

a sole for supporting a wearer's foot;

a vamp attached to the sole for extending over a forefoot of the wearer's foot between medial and lateral margins of the sole, the vamp including a rear margin proximal of a heel of the wearer's foot;

a detachable strap including opposing first and second end sections;

first and second connector means mounted on the vamp along respective medial and lateral sides thereof and adjacent the rear margin of the vamp for detachably connecting the respective first and second end sections of the strap thereto in a first position, in which the strap extends around a heel of the wearer's foot; and

first and second holder means mounted on the vamp along the respective medial and lateral sides thereof for detachably holding the first and second end sections of the strap to the vamp in a second position, in which the strap extends over the forefoot.

13. The convertible sandal of claim 12, further comprising means for adjusting the vamp to fit the wearer's foot.

14. In a sandal having a sole for supporting a wearer's foot, a vamp attached to the sole and extending over a forefoot portion of the wearer's foot between medial and lateral margins of the sole, and a strap including opposing first and second end sections, an improved method of reconfiguring the sandal between a heel-strap configuration, in which the strap extends around a heel of the wearer's foot, and a slide configuration, in which the strap is moved clear of the heel, comprising:

providing first and second connectors on the vamp at respective medial and lateral sides of the vamp adjacent a rear margin of the vamp;

providing a holder supported on the vamp along at least one of the medial and lateral sides thereof;

connecting the first and second end sections to the first and second connectors, respectively, thereby configuring the sandal in the heel-strap configuration;

detaching at least one of the first and second end sections from the corresponding connector to which it is connected; and

detachably connecting the strap to the holder in the slide configuration.

15. The method of claim 14, wherein:

the strap includes a main portion extending between the first and second end sections;

the connectors include elongated eyelets sized for threading the first and second end sections of the strap therethrough; and

the step of connecting the first and second end sections to the first and second connectors includes threading the first and second end sections through the eyelets, folding back the first and second end sections over the main portion of the strap, and securing the first and second end sections to the main portion of the strap to thereby secure the strap to the vamp.

16. The method of claim 14, further comprising detachably connecting one of the first and second end sections to a second sandal or another article.

17. The method of claim 14, further comprising adjusting the vamp to fit the wearer's foot.

18. A convertible sandal, comprising:

a sole for supporting a wearer's foot;

a vamp attached to the sole for extending over a forefoot of the wearer's foot between medial and lateral margins of the sole, the vamp including medial and lateral sides proximal of the medial and lateral margins of the sole, respectively;

first and second connectors secured to the vamp along the respective medial and lateral sides and adjacent a rear margin of the vamp, the first and second connectors defining respective first and second eyelets; and

a heel strap including opposing first and second end sections and a main portion extending between the first and second end sections, the first and second end sections being threaded through the first and second eyelets, respectively, folded back upon the main portion of the strap, and secured to the main portion of the strap, to thereby secure the strap to the vamp.

19. The convertible sandal of claim 18, wherein the first and second end sections are releasably secured to the main portion, the heel strap is detachable from the vamp, and the vamp further includes first and second holders different from the first and second connectors, the first and second holders located along the medial and lateral sides of the vamp, respectively, for detachably securing the heel strap over the forefoot.

20. The convertible sandal of claim 18, wherein each of the first and second connectors includes a swivel connector that facilitates pivoting of the heel strap between a first position extending around a wearer's heel and a second position extending across a wearer's forefoot.

21. The convertible sandal of claim 20, wherein each swivel connector comprises:

a socket part aligned with a hole in the vamp; and

a plug part rotatably mated with the socket part through the hole; and

a pivotable body supported on one of the plug and socket parts for rotation relative to the vamp, the body defining one of the first and second eyelets.

22. The convertible sandal of claim 21, wherein the other of the plug and the socket parts not supporting the body includes a flange resting against an inner surface of the vamp, the flange including a gripping feature to grip the vamp.

23. The convertible sandal of claim 18, wherein at least one of the first and second end sections is releasably secured to the main portion with hook-and-loop fastener material.

24. The convertible sandal of claim 18, wherein:

the second end section is releasably connected to the second connector; and

the first end section is non-releasably connected to the first connector.

25. The convertible sandal of claim 24, wherein the second end section is releasably secured to the main portion with hook-and-loop fastener material.

26. The convertible sandal of claim 12, wherein each of the first and second connector means includes a swivel connector that facilitates pivoting of the strap between the first and second positions.

27. The convertible sandal of claim 26, wherein the swivel connectors include eyelets to receive the first and second end sections of the strap.

28. A convertible sandal, comprising:

a sole;

a vamp attached to the sole for extending over a forefoot of a wearer's foot between medial and lateral margins of the sole, the vamp including medial and lateral sides proximal of the medial and lateral margins of the sole, respectively;

a first connector pivotably secured to the vamp along one of the medial and lateral sides thereof;

a second connector secured to the vamp along the other of the medial and lateral sides thereof; and

a strap including opposing first and second end sections, the first end section being non-releasably connected to the first connector, the second end section being releasably connected to the second connector when in a first position in which the strap extends around a heel of the wearer's foot, and the second end section being detachable from the second connector for movement of the strap, without removal of the sandal from the wearer's foot, to a second position in which the strap extends over the forefoot and the second end section is reattached to the second connector.

29. The convertible sandal of claim 28, wherein each of the first and second connectors comprises a swivel connector.

30. The convertible sandal of claim 29, wherein each swivel connector includes:

a socket part and a plug part, the socket and plug parts rotatably mated together through a hole in the vamp, one of the socket and plug parts including a flange that rests against an inner surface of the vamp, the flange including gripping features for gripping the vamp; and

a pivotable body supported on the other of the socket and plug parts for rotation relative to the vamp.

31. The convertible sandal of claim 28, wherein the strap includes a main portion extending between the first and second end sections, the second connector including an eyelet through which the second end section is threaded, the second end section being folded back upon the main portion of the strap and releasably and adjustably secured thereto.

32. The convertible sandal of claim 31, wherein the second connector is a swivel connector including a body that rotates relative to the vamp and the eyelet is formed in the body.

33. The convertible sandal of claim 31, wherein the second end section is releasably secured to the main portion with hook-and-loop fastener material.