Woven tubular thermal sleeve and method of construction thereof

A thermal sleeve for routing and protecting elongate members and method of construction thereof are provided. The sleeve has a tubular woven wall extending along a central axis between opposite open ends with an outer reflective foil layer fixed thereto. The wall is woven with lengthwise extending warp yarns and circumferentially extending fill yarns. The fill yarns include first and second fill yarns bundled in side-by-side abutting relation as a single pick, thereby forming discrete single pick bundles in axially spaced relation from one another. The first fill yarn is provided as a standard monofilament, while the second fill yarn is provided having a low melt material melted and bonded to the abutting first fill yarn and to portions of the abutting warp yarns, wherein the spaces between the discrete bundles remain substantially free of melted material, thereby further enhancing longitudinal flexibility of the sleeve.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention relates generally to textile sleeves for protecting elongate members, and more particularly to thermally protective woven tubular sleeves.

2. Related Art

It is known to contain elongate members, such as wires, wire harnesses, cables and conduits of various types, in both tubular braided and woven textile sleeves having a reflective foil outer layer bonded thereto, such as in automobiles, aircraft and aerospace craft, to provide protection to the elongate members against abrasion, fluid and thermal affects. However, problems with the known protective sleeves have proven difficult to overcome; namely, the braided sleeves are typically loose and take on a flat profile, while the protective woven sleeves typically have a very tight weave structure to prevent the woven yarns from shifting relative to one another, and thus, the woven sleeves are generally very stiff. Both conditions present potential problems in use. With the braided sleeves, the sleeves are difficult to install as a result of being generally flat, and also have problems with the outer foil layer becoming cracked in shipment due to the relatively flimsy, flattened structure of the braided wall. Similarly, the woven sleeves can be difficult to install over meandering wires/conduit as a result of being so stiff and inflexible, which also can result in unwanted kinking of the sleeve when routed around corners. Both types of sleeves are further known to have problems with end fray, particularly upon being cold cut to length, which results when the yarns fall out the open ends of the sleeves.

Accordingly, what is needed is a sleeve that provides a balance between maintaining a round, tubular form to facilitate installation over elongate members and to prevent cracking of an outer foil layer, such as during shipment, while at the same time being flexible enough to allow the sleeve to be readily installed over meandering paths while also prevent kinking when routed about corners, and further, resists end fray upon being cold cut to length and while in use.

SUMMARY OF THE INVENTION

One aspect of the invention provides a thermal sleeve for routing and protecting elongate members. The sleeve has an elongate, tubular woven wall extending along a central axis between opposite open ends with an outer layer of reflective foil fixed thereto. The wall is woven with warp yarns extending parallel to the central axis and fill yarns extending transversely to the warp yarns. The fill yarns are provided as first fill yarn and second fill yarn, wherein the first fill yarn is bundled with the second fill yarn in side-by-side abutting relation. As such, the first fill yarn and second fill yarn are woven together as a single pick, thereby forming discrete single pick bundles extending circumferentially about the central axis, with the discrete bundles being spaced axially from one another along the length of the sleeve to enhance longitudinal flexibility of the sleeve. The first fill yarn is provided as a standard monofilament, such as of natural PET, while the second fill yarn is provided, at least in part, as a low melt yarn, with the second fill yarn being melted and bonded to the abutting first fill yarn and to portions of the abutting warp yarns, wherein the spaces between the discrete bundles remain substantially free of melted material, thereby further enhancing longitudinal flexibility of the sleeve.

In accordance with another aspect of the invention, the second fill yarn can be provided as a bicomponent monofilament having a heat-set core and an outer sheath melted and bonded with adjacent yarns.

In accordance with another aspect of the invention, the warp yarns can be provided as multifilaments.

In accordance with another aspect of the invention, the warp yarns can be provided as glass-fiber multifilaments.

In accordance with another aspect of the invention, the outer foil layer can be spiral wrapped about the woven wall.

In accordance with another aspect of the invention, the outer foil layer can be cigarette wrapped about the woven wall.

In accordance with yet another aspect of the invention, a method of constructing a thermal sleeve is provided. The method includes weaving an elongate tubular wall with warp yarns extending parallel to a central axis between opposite open ends of the wall and fill yarns extending transversely to the warp yarns. The method further includes providing the fill yarns including first fill yarn and second fill yarn bundled in side-by-side relation and weaving the bundled first and second yarns as a single pick, thereby forming discrete, single pick bundles of the first and second yarns extending circumferentially about the central axis, with the discrete bundles being spaced axially from one another along the length of the sleeve, wherein the spaces provide enhanced longitudinal flexibility to the sleeve. The method further includes providing the first fill as a standard monofilament, such as of natural PET, and providing the second fill yarn, at least in part, as a low melt yarn. Further yet, the method includes applying an outer layer of foil on an outer surface of the woven wall. The method further includes disposing the woven wall over a mandrel and heating the second fill yarn to cause at least a portion of the second fill yarn to melt and bond with the abutting first fill yarn and abutting portions of the warp yarn, thereby acting to lock the bonded yarns together, while leaving at least a portion of the spaces between the discrete bundles free of melted material, thereby further enhancing longitudinal flexibility of the sleeve.

In accordance with another aspect of the invention, the method can further include providing the second fill yarn as a bicomponent monofilament having a heat-settable core and an outer meltable sheath, and while heating the second yarn on the mandrel, causing the outer sheath to melt and bond with adjacent yarns and causing the inner cored to take-on a heat-set.

In accordance with another aspect of the invention, the method can further include providing the warp yarns as multifilaments.

In accordance with another aspect of the invention, the method can further include providing the warp yarns as glass-fiber multifilaments.

In accordance with another aspect of the invention, the method can further include spiral wrapping the foil layer about the woven wall.

In accordance with another aspect of the invention, the method can further include cigarette wrapping the foil layer about the woven wall.

In accordance with another aspect of the invention, the method further includes weaving the fill yarns having a picks per inch greater than 6.

In accordance with another aspect of the invention, the method includes weaving the fill yarns having a picks per inch between about 6 and 14.

In accordance with another aspect of the invention, the method can further include weaving 2 passes of the first fill yarn and 2 passes of the second fill yarn in each pick.

In accordance with another aspect of the invention, the method can further include weaving the tubular wall on a flatbed needle loom.

In accordance with another aspect of the invention, the method can further include weaving the tubular wall on a shuttle loom.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring in more detail to the drawings,FIG. 1shows a schematic representation of a thermally protective tubular woven sleeve, referred to hereafter as sleeve10, constructed in accordance with one aspect of the invention. It is to be understood that by tubular, it is meant that the sleeve10has a circumferentially continuous wall12, and that it does not have free lengthwise extending side edges. The sleeve10is intended for routing and protecting elongate members14, such as wires, a wire harness, or conduit, for example, from exposure to abrasion and the ingress of contamination, debris and the like, while also shielding the elongate members14against exposure to heat. The elongate wall12extends lengthwise along a central axis16and bounds a circumferentially enclosed cavity18that extends along the central axis16between opposite open ends20,22. The wall12is woven with warp yarns24and fill yarns, wherein the fill yarns include first fill yarn26aand second fill yarn26b. The first fill yarn26ais bundled with the second fill yarn26bin side-by-side, abutting relation. As such, the first fill yarn26aand second fill yarn26bare woven together as a single pick of yarn in side-by-side relation, thereby forming discrete bundles28extending circumferentially about the central axis16, with the discrete bundles28being spaced axially from one another by discrete fill yarn free spaces29along the length of the sleeve10. The spaces29have an axially extending width extending between adjacent bundles28approximately equal to the width of the individual bundles28. The fill yarn free spaces29function to provide enhanced longitudinal flexibility to the sleeve10, for reasons discussed in more detail below. It should be recognized that the width of the individual spaces29can be altered as necessary to selectively increase or decrease the longitudinal flexibility of the sleeve10by adjusting the picks-per-inch, as desired for the intended application. The picks-per-inch can be adjusted over the length of the sleeve10, such that the sleeve10can possess select regions of increased flexibility as a result of a decreased number of picks-per-inch and regions of increased stiffness as a result of increased number of picks-per-inch.

The first fill yarn26ais provided as a standard monofilament, such as of natural PET, while the second fill yarn26bis provided as a low melt yarn formed, at least in part, of a low melt material25extending along the entire length of the outer surface of the second fill yarn26b. With the low melt material25of the second fill yarn26bbeing melted during construction of the sleeve10, the second fill yarn26bis caused to bond with the abutting first fill yarn26aand abutting portions of the warp yarns24. To enhance the flexibility of the sleeve10, at least a portion of the discrete spaces29remain free of the melted material of the second fill yarn26b. It should be recognized that the melted material of the second fill yarn26bsolidifies upon being melted, whereupon the solidified material possesses an increased stiffness. Accordingly, the spaces29, being free of the solidified material, provide enhanced longitudinal flexibility to the sleeve10.

To protect and shield the elongate members14from exposure to external heat and against the ingress of contaminants, a reflective outer layer30is fixed, such as being bonded via a suitable high temperature adhesive, to an outer surface32of the woven wall12.

The wall12is constructed to maintain a generally round shape, thereby avoiding flattening under its own weight and resists end-fray, which is an undesirable condition resulting from fill yarns falling out the ends20,22of the sleeve, via melted and bonded portions of the second fill yarn26b. To further enhance the ability of the wall12to maintain its round shape, the second fill yarn26b, in addition to having its outer surface at least partially melted, can also be provided to be heat-set. Accordingly, in accordance with a presently preferred embodiment, the second fill yarn26bis provided as both a heat-settable yarn and as a low melt yarn, such as, by way of example and without limitation, as shown inFIG. 4A, a dual functioning bicomponent yarn. The bicomponent weft yarn26bincludes a central core27and an outer sheath25, wherein the outer sheath25is a low melt material having a lower melt temperature than the central core27to facilitate melting and bonding the outer sheath with adjacent, abutting yarns, thereby acting to lock the abutting fill and warp yarns in place with one another and preventing end fray upon cold cutting the sleeve wall12to length. The central core27is provided as a heat-settable material to maintain the yarns26b, and thus the wall12, in a generally round configuration, as viewed in lateral cross-section taken generally transversely to the central axis16. Although bicomponent yarn26bis preferred for the second fill yarn26b, other types of yarn are considered herein, such as heat, water, or pressure activated material that melts, bonds, or activates under certain conditions to secure the yarns in the woven structure to one another. The material of the second fill yarn26bcan also include adhesive coated yarns or strips of material, entanglement, twisting, or incorporating materials of different melting temperatures and/or activation properties into one yarn, whether monofilament or multifilament. Further yet, as shown inFIG. 4B, it is contemplated that the second fill yarn26bcan be provided as a monofilament of low melt material25having a melt temperature less than the melt temperature of the first fill yarns26a. In addition, to provide abrasion resistance and additional hoop strength, the first fill yarn26acan be provided as a natural PET monofilament, by way of example and without limitation.

In one exemplary embodiment, both the fill yarns26a,26bwere provided as 0.38 mm monofilaments, and were woven with the warp yarns24in a plain weave pattern of 9 picks-per-inch (PPI), with each bundle28extending over and under every other alternating warp yarn24, and with each warp yarn24extending over and under every other alternating bundle28. The warp yarns24were provided as glass-fiber multifilaments having a denier of 3822 and a warp density of 21 ends, by way of example and without limitation. It should be recognized that other types of warp yarn are contemplated herein, such as multifilaments of standard or natural PET, by way of example and without limitation. It should also be recognized that other types of weave patterns are contemplated herein, such as a basket and twill weave patterns, for example, and further, the diameter of the fill yarns can be any suitable diameter.

Upon weaving the circumferentially continuous wall12, the reflective outer layer30can be fixed or bonded to the outer surface32of the wall12. The reflective outer layer30can be any suitable wrappable metal foil, such as aluminum, for example, wherein the layer30can have any desired thickness suitable to provide the desired durability and flexibility. As shown inFIG. 1, the reflective outer layer30can be provides as a generally narrow strip of material that is helically wrapped about the outer surface32of the wall12of the sleeve10, or as shown inFIG. 1A, the outer layer30′ can be provided having a width slight greater than the outer circumference of the wall12, such that it can be wrapped in “cigarette” fashion about the outer surface32of the wall12of the sleeve10′ to bring opposite, lengthwise extending edges into overlapping relation with one another. Regardless of which wrapping construction is used, a suitable adhesive can be used to bond overlapping edges of the respective reflective layer30,30′ to themselves and/or to bond the reflective outer layer30,30′ directly to the outer surface32of the wall12.

In accordance with another aspect of the invention, a method of constructing a thermally protective tubular sleeve10is provided. The method includes weaving an elongate tubular wall12with warp yarns24extending parallel or substantially parallel to a central axis16between opposite open ends20,22of the wall12and fill yarns extending transversely or substantially transversely to the warp yarns24. The method further includes providing the fill yarns including first fill yarn26aand second fill yarn26bbundled in side-by-side relation with one another and weaving the bundled first and second fill yarns26a,26bas a single pick, thereby forming discrete bundles28of the first and second yarns26a,26bextending circumferentially about the central axis16, with the discrete, single pick bundles28being spaced axially from one another along the length of the sleeve10by discrete spaces29, which function to providing the sleeve10with enhanced longitudinal flexibility. The method further includes providing the first fill26aas a standard monofilament, such as of natural PET, and providing the second fill yarn26b, at least in part, as a low melt yarn material25. Further yet, the method includes wrapping an outer layer of foil30about an outer surface32of the woven wall12. The method further includes disposing the woven wall12over a mandrel and heating the second fill yarn26bto cause at least a portion of the fill yarn26bto melt, solidify and bond with the abutting first yarn26aand abutting portions of the warp yarns24, thereby acting to lock the bonded yarns together, while at the same time, leaving at least a portion of the spaces29free of melted material, thereby retaining enhanced longitudinal flexibility of the sleeve10via the spaces29.

In accordance with another aspect of the invention, the method can further providing the second fill yarn26bas a bicomponent monofilament having a heat-settable core27and an outer meltable outer sheath25, and while heating the second yarn26bon the mandrel, causing the outer sheath25to melt and bond with adjacent yarns24,26aand causing the inner core27to take-on a heat-set shape, thereby providing enhanced hoop strength to the sleeve10and acting to maintain the sleeve10having a generally round shape as viewed in lateral cross-section (FIG. 2).

In accordance with another aspect of the invention, the method can include providing the warp yarns24as multifilaments, such as glass-fiber multifilaments or PET multifilaments, for example.

In accordance with another aspect of the invention, the method can include wrapping the foil layer30about the woven wall in a cigarette wrapped fashion (FIG. 1A) or helically wrapped fashion (FIG. 1).

In accordance with another aspect of the invention, the method includes weaving the fill yarns having a picks-per-inch (PPI) greater than 6, and in one exemplary embodiment, having a PPI between about 6 and 14, such as 9, for example. It is to be recognized that the PPI could be formed deviating at least slightly beyond the aforementioned limits, though testing has shown optimal performance under the test conditions between 6 and 14 PPI.

In accordance with another aspect of the invention, to enhance the finished hoop strength of the sleeve10,10′, the method can include weaving 2 passes of the first fill yarn26aand 2 passes of the second fill yarn26bin each pick, thereby forming each of the bundles28having 4 abutting yarn segments, with each bundle28being separated axially from one another by the intervening space29.

In accordance with another aspect of the invention, the method can include weaving the tubular wall12on a flatbed needle loom or on a shuttle loom.