MATTRESS WITH VARIABLE FRICTION FLAME BARRIER CAP AND RELATED METHOD

Abstract

An improved mattress FR cap structure incorporating skirting with zones of different friction character. The skirting incorporates a first zone positioned for placement across upper portions of the mattress' vertical sides and a second zone positioned for placement over lower edges of the vertical sides. The first zone forms a first high friction interface with the underlying mattress foam or other material providing substantially stable, fixed positioning between the first zone and the underlying material restricting relative movement. The second zone provides a low friction interface with the underlying mattress foam or other material permitting relative movement between the second zone and the underlying material during compression and/or recovery. The FR cap may also include a third zone positioned for placement adjacent to the second zone for disposition at the underside of the mattress in the final construction and providing a second high friction interface with the underlying material.

Claims

1. A mattress comprising: a resilient foam core; and a flame barrier cap disposed over the core, wherein the flame barrier cap comprises a stitch-bonded flame resistant skirting disposed in overlying relation to sides of the core, wherein the skirting comprises at least one length of stitch-bonded fabric comprising a plurality of elastomeric stitching yarns disposed in stitched relation through a flame retardant fleece substrate in stitch lines running in the machine direction of the fabric, the skirting further comprising an irregular polymer surface layer of heat activated meltable polymer, the skirting comprising a first zone disposed in covering relation to upper portions of the sides, the first zone comprising a plurality of raised globules formed by the meltable polymer, said raised globules projecting outwardly away from the flame retardant fleece and positioned to engage the core, the skirting further comprising at least a second zone disposed below the first zone, wherein the second zone wraps around lower edges of the core, and wherein the first zone has higher sliding friction relative to the core than the second zone, the skirting further comprising a gripping power zone extending inboard from a distal free edge of the skirting adapted to grip the underside of the core.

2. The mattress as recited in claim 1, wherein the first zone further includes a plurality of perforations between stitch lines

3. The mattress as recited in claim 1, further comprising a third zone disposed between the second zone and the gripping power zone, said third zone comprising a plurality of raised globules formed by the meltable polymer and having higher sliding friction relative to the core than the second zone.

4. The mattress as recited in claim 1, wherein the fleece substrate comprises a plurality of carded and cross-lapped flame-resistant staple fibers.

5. The mattress as recited in claim 4, wherein the fleece substrate further comprises 1% to 20% heat activated bicomponent polyester.

6. The mattress as recited in claim 4, wherein at least a majority of the staple fibers are FR Rayon.

7. The mattress as recited in claim 4, wherein at least a majority of the staple fibers are oriented within plus or minus 30 degrees of a line running perpendicular to the machine direction.

8. A mattress comprising: a resilient foam core; and a flame barrier cap disposed over the core, wherein the flame barrier cap comprises a top panel of flame resistant fabric disposed in overlying relation to a substantially planar upper surface of the core, the flame barrier cap further comprising a stitch-bonded flame resistant skirting disposed in overlying relation to sides of the core, wherein the skirting comprises at least one length of stitch-bonded fabric comprising a plurality of elastomeric stitching yarns disposed in stitched relation through a flame retardant fleece substrate in stitch lines running in the machine direction of the fabric, the skirting further comprising an irregular polymer surface layer of heat activated meltable polymer, the skirting comprising a first zone disposed in covering relation to upper portions of the sides, the first zone comprising a plurality of raised globules formed by the meltable polymer, said raised globules projecting outwardly away from the flame retardant fleece and positioned to engage the core, the skirting further comprising at least a second zone disposed below the first zone, wherein the second zone wraps around lower edges of the core, and wherein the first zone comprises a first plurality of stitch lines and the second zone comprises a second plurality of stitch lines, the second zone having an average stitching gauge with at least 50% more stitch lines per inch than the first zone, and wherein the first zone has higher sliding friction relative to the core than the second zone, the skirting further comprising a gripping power zone extending inboard from a distal free edge of the skirting adapted to grip the underside of the core, the gripping power zone having an average stitching gauge greater than the second zone.

9. The mattress as recited in claim 8, wherein the first zone further includes a plurality of perforations between stitch lines

10. The mattress as recited in claim 8, further comprising a third zone disposed between the second zone and the gripping power zone, said third zone comprising a plurality of raised globules formed by the meltable polymer and having higher sliding friction relative to the core than the second zone.

11. The mattress as recited in claim 8, wherein the fleece substrate comprises a plurality of carded and cross-lapped flame-resistant staple fibers.

12. The mattress as recited in claim 11, wherein the fleece substrate further comprises 1% to 20% heat activated bicomponent polyester.

13. The mattress as recited in claim 11, wherein at least a majority of the staple fibers are FR Rayon.

14. The mattress as recited in claim 4, wherein at least a majority of the staple fibers are oriented within plus or minus 30 degrees of a line running perpendicular to the machine direction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which are incorporated in, and which constitute a part of this specification, illustrate exemplary constructions and procedures in accordance with the present disclosure and, together with the general description of the disclosure given above and the detailed description set forth below, explain the principles of the disclosure wherein:

[0018] FIG. 1 is a partial cut-away view of an exemplary mattress construction consistent with the present disclosure;

[0019] FIG. 2 is a schematic view of an exemplary covered mattress core illustrating a cap with a top panel and attached skirting of FR fabric with MD stretch and recovery consistent with the present disclosure defining side panels wherein the attached skirting includes distal edge zones with enhanced high stretch and recovery power at the underside of the core;

[0020] FIG. 3 illustrates gripping globules of melted and resolidified polymer disposed across an underlying fiber fleece;

[0021] FIG. 4 is a schematic showing an arrangement of high friction zones and low friction zones in an FR cap skirt consistent with the present disclosure; and

[0022] FIG. 5 is a schematic view illustrating a potentially preferred arrangement of high friction and low friction skirting surfaces across an underlying mattress core.

[0023] While constructions consistent with the present disclosure have been illustrated and generally described above and will hereinafter be described in connection with certain potentially preferred embodiments and practices, it is to be understood that in no event is the disclosure limited to such illustrated and described embodiments and practices. On the contrary, it is intended that the present disclosure shall extend to all alternatives and modifications as may embrace the general principles of this disclosure within the full and true spirit and scope thereof. Also, it is to be understood that the phraseology and terminology used herein are for purposes of description only and should not be regarded as limiting. The use herein of terms such as “including” and “comprising” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof.

DESCRIPTION

[0024] Reference will now be made to the drawings, wherein to the extent possible like reference numerals are utilized to designate corresponding components throughout the various views. In FIG. 1 there is illustrated a mattress 10 having an upper face 12 and vertical sides 14. In the illustrated exemplary construction, the mattress 10 generally includes a core 16 of foam or other material. By way of example only, and not limitation, the foam may be a visco-elastic polyurethane foam, latex foam, or the like having a density of about 1-12 pounds per cubic foot and more preferably about 3 to 7 pounds per cubic foot although other resilient materials and densities may likewise be utilized. The core 16 may have a continuous stiffness throughout the thickness of the mattress 10 or may be layered with different materials and varying stiffness levels at different positions in the thickness dimension.

[0025] In the illustrated arrangement, the core 16 is at least partially covered with an overlay structure 20 including a stretchable FR cap 22 disposed in form-fitting relation around the core 16 to cover at least the top and sides of the core 16. As will be described further hereinafter, a portion of the stretchable cap 22 may also be disposed across a portion of the underside of core 16 (FIG. 2). The overlay structure may also include a decorative outer covering 24 such as a circular knit ticking fabric or the like covering the stretchable cap 22 at the tops and sides of the mattress. Alternatively, the stretchable cap 22 may define the outer covering such that no additional covering layer is required.

[0026] In the illustrated exemplary construction, the stretchable cap 22 is preferably free from any physical connection to covering layer 24 if one is used. However, the stretchable cap 22 and any outer covering 24 may be connected if desired. Such connection may be at intermediate discreet positions or may be along a substantially continuous interface. By way of example only, such connection may be made by quilting, adhesive bonding or other techniques as may be known to those of skill in the art.

[0027] Referring to FIG. 2, in the exemplary construction the stretchable cap 22 includes a top panel 30 adapted to overlay the top of core 16 defining a substantially horizontal support surface during use. The stretchable cap 22 also includes stitch-bonded skirting 31 operatively connected around the perimeter of the top panel 30. Skirting 31 is adapted to cover the vertical sides of core 16 and preferably extend at least partially across the underside of core 16. As will be appreciated, while the stretchable cap 22 may be in direct contact with both core 16 and any ticking or other decorative outer covering 24, it is likewise contemplated that one or more intermediate layers may be interposed between the stretchable cap and the core 16 and/or between the stretchable cap 22 and any outer covering 24. Moreover, as noted previously, outer covering 24 may be eliminated if desired. Both the top panel 30 and the skirting 31 are flame retardant such that the stretchable cap provides a flame barrier over the core 16.

[0028] In stretchable cap 22, the skirting 31 is preferably formed by stitch-bonding a fleece material in juxtaposed relation with a layer of meltable polymer material to form a coordinated stitch-bonded structure. As will be understood by those of skill in the art, stitch-bonding is a well-known fabric formation process in which rows of stiches are applied through one or more layers of material such as fleece, scrim, or the like to form a coordinated structure.

[0029] In one exemplary practice consistent with the present disclosure, a meltable polymer scrim of polyester, nylon, polypropylene, or the like may be stitch-bonded or otherwise secured to the top panel 30 for disposition between the top panel and the core 16. In this regard, it is also contemplated that the meltable polymer material may be secured to the top panel or skirting fleece by techniques other than stitch-bonding such as patterned point bonding using adhesives and the like. After formation, the skirting material (and optionally the top panel) may be heated to melt the polymer material at least partially and form globules of resolidified polymer upon cooling adapted to grip the underlying mattress material during use.

[0030] By way of example only, one exemplary stitching base for skirting 31 may be flame retardant silica rayon fiber fleece blended with about 1% to 20% (15% preferred) core/sheath bicomponent polyester or other polymer fiber with a low melting point constituent. However, other fleece materials may be used if desired. By way of example only, such other materials may include rayon fibers treated with FR (“flame retardant”) chemicals, para-aramid, meta-aramid, modacrylic, wool and other fibers with FR properties. Materials such as FR treated or coated polyester or cotton and blends of any of the foregoing may also be used if desired. All such materials are flame retardant fibers. One contemplated blend which may be particularly desirable is flame retardant silica rayon fiber blended with some percentage of para-aramid and/or meta-aramid fiber. One exemplary blended fibrous substrate material may be a blend of about 95% flame retardant silica rayon fiber and about 5% Para-aramid fiber. Higher percentages of Para-aramid fiber up to about 25% or more may be used if desired.

[0031] During stitch-bonding formation of skirting 31, the stitching fleece or other substrate is preferably fed in layered relation with the polymer scrim to a row of stitching needles extending at least partially across the width of the fabric. The layered materials are then stitched with elastomeric stitching yarns such as covered Spandex or the like to impart machine direction (MD) stretch and recovery. In this regard, the term elastomeric stitching yarns will be understood to mean stitching yarns with the ability to stretch at least 50%, and more preferably at least 100% prior to breakage and which will return to within 10% of their initial length within one hour following 50% stretching under standard atmospheric conditions. That is, the length after stretching to 50%, holding the stretched condition for not more than 5 seconds, and release will be not more than 110% of the length before stretching when measured after 1 hour at ambient conditions and will more preferably be in the range of 100% to 105% of the length before stretching. By way of example only, one exemplary stitching yarn is a 40 denier covered Spandex, although other elastomeric materials and/or deniers may be used if desired.

[0032] Following stitching, the resulting fabric may then be relaxed with steam or other suitable heat treatment thereby causing the elastomeric stitching yarns to shrink. This shrinking imparts stretch capacity in the machine direction of the stitched fabric. The steamed fabric may then be dried at a temperature and duration adequate to activate any bicomponent sheath material at least partially thereby imparting fiber-to-fiber bonds promoting cross direction (CD) stability. A temperature of about 190C may be preferred. Activating the bicomponent fiber in a steaming and drying process may improve the dimensional stability of the skirting in the CD. Such improved dimensional stability may aid in avoiding visual puckers and thin areas after the cap is applied over the mattress core.

[0033] The steaming and/or heating step(s) will also preferably cause the applied meltable polymer scrim to melt at least partially and to form large globules within selected stitching zones across the fabric width. These globules provide high friction surfaces within the skirting for placement at desired locations relative to the mattress core 16 as will be described.

[0034] After stitching and heat treatment, the skirting 31 may be cut as a one-piece strip in the machine direction. The strip is then sewn along one of its longitudinal edges in a substantially fully extended state around the entire perimeter of top panel 30 using FR sewing thread such as Kevlar or the like. In this construction, top panel 30 provides FR protection to the top surface of the mattress and is sewn in a relaxed, non-extended state to the fully extended skirting 31. As shown in FIG. 2, a final, single vertical seam 35 using FR sewing thread may then be used to attach the leading edge of the skirting 31 to its trailing edge to complete the stretchable cap 22. Of course, such a seam is not limited to a single sewn seam as illustrated and can be an overlocked seam or any other connecting seam that allows suitable closure of the “skirting loop” sewn around the top FR panel.

[0035] In accordance with one exemplary practice, the skirting 31 be a stitch bonded fabric using a stitching fleece 37 of 100% FR Rayon fiber fleece with a mass per unit area of about 120 gsm (grams per square meter). However, other suitable materials may likewise be utilized if desired. The meltable polymer layer used in the skirting (and optionally at the top panel) is preferably a light-weight nonwoven or scrim of meltable polymer material such as a nylon, polyester, polypropylene or the like positioned on one side of the fleece in the skirting before stitch-bonding so that this layer is on the side of the skirting that eventually interfaces with the mattress core material. A polypropylene spunbond having a mass per unit area of about 8 to 20 grams per square meter (gsm) and preferably about 12 gsm may be particularly preferred.

[0036] As previously indicated, it has been observed that under some circumstances a mattress cap skirting may be urged to shift relative to the underlying core when the mattress is rolled in compressed condition and then unpackaged. If this shift occurs, an undesired fold along the vertical sides may be produced. In accordance the present disclosure, the occurrence of undesired side folds may be prevented by incorporating the meltable polymer attachment which may be heated to at least partially melt the attached polymer such that the melted material forms large globules 38 of resolidified polymer in designated zones (FIG. 3).

[0037] Referring now to FIG. 4, the skirting 31 of the improved FR cap preferably incorporates a first zone 40 positioned for placement across upper portions of the mattress' vertical sides and a second zone 42 positioned for placement over lower edges of the vertical sides. In this regard, the first zone 40 will preferably have a height dimension which is less than the height of the mattress being covered. By way of example only, a height of about 8 inches (20.3 cm) may be appropriate for use with most mattresses. First zone 40 forms a high friction interface with the underlying mattress foam or other material. This high friction interface provides stable, fixed positioning between the first zone and the underlying material so as to minimize relative displacement during rolled compression and subsequent recovery.

[0038] In accordance with one exemplary construction, first zone 40 may be stitched at about 3.5 gauge (i.e., threaded needles per inch) but with about 14 total needles per inch to promote enhanced perforation between stitch lines for breaking up the meltable polymer to form larger globules. That is, a large percentage of the needles are not threaded with stitching yarns and merely apply perforations through the fabric during the stitching process. Such needling by unused needles promotes the breakup of the polymer scrim and may be useful in the formation of large friction-inducing globules 38.

[0039] The second zone 42 provides a substantially lower friction interface with the underlying mattress foam or other material due to a significantly lower concentration of large globules. This low friction interface permits relative movement between the second zone 42 and the underlying material so as to permit a degree of relative displacement when the mattress during compression and/or recovery. In accordance with one exemplary construction, the second zone 42 may be stitched at about 7 needles per inch without extra unthreaded needles. As will be appreciated, this produces significantly closer stitching lines. In this regard, the stitching gauge within the second zone 42 preferably has at least 50% more stitch lines per inch than the first zone and more preferably 70%-150% more stitch lines per inch than the first zone. Closer stitching been found to reduce the formation of large globules and reducing friction. Second zone 42 preferably has a height sufficient to extend around the lower edge of the mattress core and at least partially across the bottom. By way of example only, a height of about 8 inches (20.3 cm) may be appropriate for use with most mattresses.

[0040] The improved FR cap also preferably includes a third zone 44 defining a second high friction zone with stitching similar to the first zone 40. The third zone 44 is positioned for placement adjacent to the second zone 42 at the underside of the mattress. The third zone forms a high friction interface of large globules engaging with the underlying material so as to minimize relative displacement during compression and/or recovery. Third zone 44 preferably has a height sufficient to establish a reasonable gripping force across the underside of the mattress core. By way of example only, a height of about 4 inches (10.2 cm) may be appropriate for use with most mattresses.

[0041] As illustrated, skirting 31 may also include a power stretch band 45 along the lowermost edge, By way of example only, such a power stretch band 45 may be formed by an arrangement of about 10-15 Spandex yarns stitched at about 14 needles per inch.

[0042] Referring now to FIG. 5, it will be seen that in the final construction the first zone 40 defining a high friction surface preferably extends downward from the upper edge of the mattress core to an intermediate position on the vertical side. The second zone 42 defining a reduced friction surface preferably extends from a position on the vertical side around the lower edge. The third zone 44 defining a second high friction surface is preferably disposed across the underside of the mattress and is bordered by a power band formed from a high concentration of stitched elastomeric yarns along the edge to assist in holding the cap in place.

[0043] In accordance with one exemplary practice, the fibers in the fleece stitching substrate used to form the skirting 31 may be oriented predominantly in the cross-machine direction (“CD”). That is, the direction across the machine and substantially perpendicular to the travel direction during stitching. In this regard, the fleece stitching substrate used to form the skirting 31 is preferably formed from a plurality of staple length fibers having an average length in the range of about 1 to 5 inches. These staple fibers may be carded and cross-lapped with an optional subsequent needling step to form a fleece structure wherein the majority of the fibers are oriented substantially in the CD. In such a carded and cross-lapped fleece structure the fibers predominantly form an angle within plus or minus 30 degrees of a line parallel to the CD. That is, the majority of the fibers will be substantially aligned within 30 degrees to the CD. Since a fiber in a nonwoven construction does not typically extend in a straight line, the orientation of a fiber relative to a reference line may be defined by reference to a line connecting the fiber ends as described in U.S. Pat. No. 9,090,801 to Siebert et al. which is hereby incorporated by reference in its entirety.

[0044] Maintaining fiber orientation predominately in the CD reduces the recoverable stretch capacity in the CD after stitching. In this regard, the term “recoverable stretch capacity” will be understood to be the percent elongation of a sample under tension which is followed by recovery to within 3% of the starting length after 1 minute under ambient conditions

[0045] The skirting 31 in the stretchable cap may be characterized by substantial recoverable stretch capacity in the MD of at least 25% such that a sample stretched in the MD by 25% (or less) in accordance with the above procedure will return to within 3% of its initial length within 1 minute after tension is removed. More preferably, the skirting 31 may be characterized by recoverable stretch capacity in the MD of at least 50% such that a sample stretched in the MD by 50% (or less) in accordance with the above procedure will return to within 3% of its initial length within 1 minute after tension is removed. Most preferably, the skirting 31 in the stretchable cap may be characterized by recoverable stretch capacity in the MD of at least 90% such that a sample stretched in the MD by 90% (or less) in accordance with the above procedure will return to within 3% of its initial length within 1 minute after tension is removed.

[0046] The skirting 31 may be characterized by substantially less recoverable stretch capacity in the CD than in the MD. That is, the recoverable stretch capacity in the skirting is not balanced. In accordance with one exemplary practice, the recoverable stretch capacity of the skirting 31 in the CD is not more than 65% of the recoverable stretch capacity of the skirting in the MD and is more preferably not more than 10% to 55% of the recoverable stretch capacity of the skirting in the MD.

[0047] In the potentially preferred practice, the skirting 31 is formed from fabric cut in the machine direction (i.e. parallel with the stitch lines). Thus, the stitch lines of elastomeric yarn will be oriented generally around the mattress core perimeter in an encircling orientation. As will be appreciated, when the stretchable cap 22 is installed on the core 16, the skirting 31 formed from FR fabric with MD stretch will seek to pull back to its original non-extended length and will thereby “self-secure” or grip to the mattress core and provide FR protection for the vertical side surfaces of the mattress. The resulting stretchable cap 22 thus provides FR protection for both the upper surface and the 4 vertical surfaces of the mattress core. Furthermore, the fleece substrate of a stitch-bonded FR fabric with MD stretch used in the skirting 31 will conform to the mattress core and provide substantially continuous fiber coverage across underlying surfaces. That is, the stretched fabric does not form openings to create uncovered areas. Such continuous fiber coverage enhances FR protection to the underlying mattress core.

[0048] The resulting stretchable cap 22 also provides partial FR protection for a zone of about 3 inches to 10 inches or greater inboard from the underside perimeter of the mattress core. In this regard, it is contemplated that so called “Filler Cloth” (not shown) used on the outer ticking cover or attached to the free edge of skirting 31 may provide further FR protection to the bottom side of the mattress in inboard zones not covered by the skirting 31.

[0049] In accordance with another exemplary practice, a percentage of bicomponent fiber having a lower melting point sheath surrounding a higher melting point core may be blended into the fiber forming the fleece used to produce the FR skirting. The percentage of bicomponent may be in the range of about 1% to 20% and will most preferably be about 15%. Activating the bicomponent fiber in a steaming and drying process may improve the dimensional stability of the skirting in the CD. Such improved dimensional stability may aid in avoiding visual puckers and thin areas after the cap is applied over the mattress core.

[0050] Preferred embodiments of this disclosure are described herein, including the best mode known to the inventors for carrying out the disclosure. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the disclosure to be practiced otherwise than as specifically described herein. Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.

[0051] The use of the terms “a” and “an” and “the” and similar referents in the context of describing the disclosure (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the disclosure and does not pose a limitation on the scope of the disclosure unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the disclosure. The contents of all prior applications and published documents referenced herein are hereby incorporated by reference in their entirety.