Patent Publication Number: US-2021169245-A1

Title: Unitary Elastic Mattress Cover and Method for Manufacturing Same

Description:
FIELD OF THE INVENTION 
     The present application relates to a novel unitary cover for a mattress with elastic peripheral skirts or sides and an improved method for manufacturing same. 
     BACKGROUND OF THE INVENTION 
     Mattress pads and fitted bed sheets with elastic sides or skirts are known commercially and in the patent literature. The elastic sides hug the mattress and are tucked under the mattress to maintain the top surface of the pads or fitted sheets on top of the mattress. 
     U.S. Pat. No. 5,187,952 to D. P. Zafiroglu teaches a stretchable stitchbonded fabric that can be formed into conformable apparel, fitted furniture covers or fitted bed sheets. This fabric is stitched with elastic yarns to form at least two longitudinal regions of different stretchability. U.S. Pat. No. 5,308,674 also to D. P. Zafiroglu teaches a stitchbonded fabric that has high tear resistant strength and is stitched with non-elastomeric, bulkable yarns. This fabric is also used to make the skirts or sides of fitted bed sheets. U.S. Pat. No. 5,603,132 also to D. P. Zafiroglu teaches a fitted mattress cover having a highly stretchable skirt or side. The skirt is stretchable by at least 50% and by at least 100% respectively in the longitudinal and transverse directions. At least 80% of the longitudinal stretch and at least 30% of the transverse stretch are elastically recoverable. The stitching yarns include inelastic yarns stitched in a tricot pattern and elastic combination yarns stitched in a different pattern. U.S. Pat. No. 6,883,193 to L. C. Brooks et al. discloses a fitted mattress cover wherein the top panel overlying the mattress has 25% to 150% elastic stretch. 
     U.S. Pat. No. 1,267,593 to J. Roever discloses a bed cover made from a blank sheet with four sides folded down along lines that coincide with the edges of the mattress. The sides are cut to form flaps, and the corner flaps are connected to a bridging section with an elastic portion by buttons to form the ends of the cover. Elastic skirting is present only along the bridging part along the ends of the mattress. U.S. Pat. No. 2,499,698 to G. G. Thomas discloses a blank with corner flaps and bottom flaps designed to cover the top and bottom surfaces of the mattress, as well as the sides. U.S. Pat. No. 2,462,156 to B. Berman discloses a bed sheet with corner flaps folded and attached to each other by zippers, hooks and eyes or snap fasteners. U.S. Pat. No. 4,651,371 to B. K. Hahn discloses a bed liner with Velcro®-type fasteners to releasably attach corner flaps to each other. 
     One drawback from the patent literature and commercial products is that the elastic portions located on the sides or skirts are attached to the fitted bed sheets or covers after the sheets and covers are manufactured. This methodology requires that the elastic portions be re-tensioned or re-stretched before being stitched or sewed onto the sheets or covers. This increases costs and complexity of the manufacturing process and produces mattress covers and sheets with possible misalignment between the top of the covers or sheets with the skirts or sides. Another drawback is a lack of a unitary elastic mattress cover that has the elastic materials such as elastic yarns and elastic strips incorporated into a unitary blank to improve the assembly of the blank into the mattress cover. 
     Hence, there is a need for improved mattress covers or sheets and for improved manufacturing techniques. 
     SUMMARY OF THE INVENTION 
     One aspect or embodiment of the present invention is directed to a unitary mattress cover comprising a top panel and four side panels, which include two end side panels, a left side panel and a right side panel. The top panel and the four side panels are made from a single blank of fabric, and the elastic materials are attached to at least a portion of the left and right side panels. The left and right side panels are longer than the top panel in a longitudinal direction, and wherein free edges of the left and right side panels are attached to one of the two end side panels or to each other. 
     The elastic materials may comprise elastic yarns stitch-bonded to said at least portion of the left and right side panels, or may comprise elastic strips sewn to said at least portion of the left and right side panels. At least the top panel may be stitch-bonded with elastic and/or inelastic yarns. Alternatively, the stitching on the top panel is different from the stitching the left and right side panels. 
     The single blank of fabric may comprise a single layer of a woven, knit or nonwoven fabric or may comprise more than one such layer. The left and right panels may further comprise an additional layer. The top panel may further comprise at least one additional layer. The at least one additional layer may be a cushion layer. Alternatively, the at least one additional layer may be a film or a liquid resisting breathable membrane. 
     Preferably, the stitch-bonded yarns may comprise re-stretchable cross gathering to facilitate form fitting and tucking around the edges under a mattress being covered by the unitary mattress. 
     Preferably, the unitary mattress cover may further comprise second elastic materials attached to the at least portion of the left and right side panels, and the second elastic materials are different than the first elastic materials. 
     Another aspect of embodiment of the present invention is directed to a method for manufacturing a mattress cover comprising the steps of 
     a) introducing a continuous fabric to a stitch-bonding or sewing equipment, 
     b) stitching an elastic yarn under tension to a top and a bottom portion of the fabric, 
     c) cutting a section of the stitch-bonded fabric to form a blank for a mattress cover, 
     d) slitting a plurality of lines in the stitch-bonded fabric or in the blank to separate end side panels and the left and right side panels, wherein the left and right side panels are formed from the stitch-bonded top and bottom portions, and 
     e) joining edges of the left and right side panels to each other or to one of the end side panels to form the mattress cover. 
     Preferably, the tension of the elastic yarn is released after step e). 
     The end side panels and the left and right side panels are joined to a top panel. The top panel is preferably sized and dimensioned to fit a top of a mattress and the end side panels and the left and right side panels are sized and dimensioned to cover the sides of the mattress. 
     Preferably, before step c) the fabric is held under tension and coupled to a jig to maintain tension. 
     Optionally or preferably, at least one additional layer is introduced to the stitch-bonding or sewing machine, and the top panel is also stitch-bonded. Preferably, the at least one additional layer is a cushion layer. Alternatively, the at least one additional layer comprises a film or a liquid resisting breathable membrane. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings, which form a part of the specification and are to be read in conjunction therewith and in which like reference numerals are used to indicate like parts in the various views. The drawings are not to scale. 
         FIG. 1A  is a top view of a blank for a mattress cover; 
         FIG. 1B  shows the arrangement of the various panels of the blank of  FIG. 1A   
         FIG. 1C  shows the blank of  FIGS. 1A and 1B  being assembled into a mattress cover 
         FIG. 2A  is a top view of another blank for a mattress cover; 
         FIG. 2B  shows the blank of  FIG. 2A  being assembled into a mattress cover 
         FIG. 3  is a top view of the blank from  FIG. 1A  being manufactured from a roll of single layer or multilayer composite fabric(s). 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     One aspect of the present invention is directed to mattress covers or sheets formed from single blanks that uniformly covering all around the mattress, with elastic skirting produced from the same blank along all four sides and preferably continuous along all four sides that can preferably also be tucked under the mattress and provide form fitting. 
     Another aspect of the present invention is directed to improved manufacturing techniques that allow the mattress cover to be formed and finished using a single blank optionally by cutting a selected length from a continuously manufactured material rolled up into a roll, preferably and optionally with a simultaneously attached multilayer central platform, eliminating the need to build the central platform corresponding to the mattress top separately. 
     Various embodiments of the present invention relate to unitary mattress covers made from single blanks. Such blanks can be cut from rolls of fabrics, which can be woven, nonwoven or plastic materials and can be a single layer or a composite of multiple layers which may include woven, nonwoven or plastic materials. Successive blanks may be cut from the rolls and form into the inventive unitary mattress covers, as described below. Advantageously, elastic materials such as yarns and/or strips are selectively stitched or sewn into portions of the blanks preferably as the fabrics are moved along the machine direction (MD), which is the direction of movement of the fabrics along the stitching equipment/machineries. MD is also preferably a longitudinal direction (along the longer side) of the mattress covers or blanks. The elastic materials are in a stretched state when stitched or sewn into portions of the blanks. When the blanks are cut from the fabrics, the elastic materials are relaxed and shrink the portions of the blanks where the elastic materials are attached. 
     Exemplary blank  10  is illustrated in  FIGS. 1A and 1   s  sized and dimensioned to make mattress covers for king size, queen size, full size, twin size, or any other sizes. The different mattress and mattress cover sizes are known the art. The length L of blank  10  includes the length of the top of the mattress cover and the two sides at the ends, and optionally materials to tuck under the mattress for form fitting. The width W includes the width of the top of the mattress cover and the sides on the left and right, and optionally materials to tuck under the mattress for form fitting. 
     Blank  10  has top panel  12 , top side  14 , bottom side  16 , left side  18  and right side  20 . Top panel and all four sides advantageously are made from the same piece of material providing an attractive look in addition to simpler manufacturing. Left and right sides  18  and  20  have elastic materials that are stitched or sewn under tension directly onto blank  10 , namely left and right sides  18  and  20  in this embodiment. Alternatively, elastic or non-elastic stitching  28  running in MD can also be applied to the mid-section including end panels  14  and  16 , as well as top panel  12 . In one embodiment, stitching  28  along panels  12 ,  14  and  16  is the same as the stitching along panels  18  and  20 , except with a larger spacing between stitches. In another embodiment, stitching  28  along panels  12 ,  14  and  16  utilizes nonelastic yarns. Alternatively, a variety of non-shrinkable yarns with elements running in the machine and diagonal directions can be placed within panels  12 ,  14  and  16 . Extra layers of fabric or water-resistant film can optionally be placed within panels  12 ,  14 , and  16  and stitched as the end panels  18  and  20  are receiving elastic stitches, adding cushion, absorbency bulk, water resistance, antimicrobial properties and other desirable properties to these panels. Optionally, panels  12 ,  14  and  16  can have quilted pattern sewn thereon. 
     End panels  14  and  16  can be separated from left and right panels  18  and  20  at cut lines  22 , which are also in MD. All four side panels are then folded downward along fold lines  24 , and the four free edges  26  of left and right panels  18  and  20  protruding beyond lines  24  are attached under tension, by sewing or stitching or any other means, to the end panels  14  and  16  to complete the mattress cover, as illustrated in  FIG. 1C . Furthermore, as further illustrated in  FIGS. 1B and 1C , since length X of free ends  26  is smaller than one half of the length Y of end panels  14  and  16 , in order to provide elastic pull along the shorter ends of the mattress, panels  34  are cut and removed or tucked in under the mattress cover at each of the four corners, and free ends  26  are attached to portion  36 , as shown. This arrangement provides elastic skirting around all four corners, although it does not reach all the way across at the shorter ends of the mattress. The mattress cover nevertheless has a uniform appearance over the top panel  12  and all around the four elastic sides. 
     Referring back to  FIG. 1A , extra elastic sewn strips or stitched zones  29  can be attached to the outer edges of left and right panels  18  and  20  to provide extra elastic power and allow tucking and gathering of these outer edges under the mattress. Preferably, panels  18  and  20 , as well as panels  14  and  16  are sized and dimensioned to be tucked under the mattress with zones  29  be under the mattress. Optionally, the elastic stitching on panels  18  and  20  is two dimensional, allowing a degree of gathering in the cross-direction (XD) subsequently pulled out as the cover is placed over a mattress and edges/zones  29  are tucked under. Optionally, elastic sewn strips  29  or stitched zones  29  solely provide elasticity to the mattress cover. 
     Referring to  FIGS. 1B and 1C , in another embodiment end panels  14  and  16  can be utilized for other purposes. Portions  34  can be tucked under top panel  12  as free ends  26  are attached to each other or to portion  36 . Portions  34  can also be removed from blank  10  for other uses such as matching pillowcases. 
     Referring to  FIGS. 2A-B , additional materials can be removed or tucked-in from ends  14  and  16 , so that free edges  26  are longer and can be attached directly to each other to provide elastic materials on all four sides or around the skirt of the mattress cover. The elastic skirting is extended fully around the mattress by increasing the length of left and right panels  18  and  20 , and removing panels  14  and  16  altogether, or folding panels  14  and  16  under top panel  12 . This allows free ends  26  to reach across, as shown in  FIG. 2B , to be attached to each other. Length X of free edges  26  is equal to or longer than the one half of the width Y of end panels  14  and  16 , and edges  26  are attached to each other providing continuous elastic skirting on all four sides around the mattress as shown in  FIG. 2B . Optionally, edges  15  of under-folded panels  14  and  16  shown in  FIG. 2A  are allowed to meet by using longer lengths X. As another option, panels  14  and  16  can be excised and used for ancillaries such as matching pillowcases. Alternatively, elastic sewn strips or stitched zones  29  shown in  FIG. 1A  can be utilized in this embodiment either for extra elasticity or for sole elasticity. 
     In accordance with another embodiment of the present invention, an advantage made possible by the present invention is a simplified process for manufacturing the inventive mattress cover, as described above. Heretofore, elastic skirt materials are made separately from the mattress cover, which is held flat, as the elastic materials for the side panels material are held under constant and steady tension as they are attached to the mattress cover, which is a challenging process requiring high operator skills. Referring to  FIG. 3 , continuous sheet  28  that may consist of a single layer or several full-width layers, and may also carry along single or multiple central layers  40 , is fed to the stitching machinery in the MD, and stitched with elastic yarns or strips  30  shown in wavy lines, under tension along the two sides that would become left and right panels  18  and  20  and part or all of end portions  14  and  16 . Optionally, center sheets  40 , which primary underlie top panel  12  and end panels  14  and  16 , are also being fed, as shown, and additional elastic or nonelastic stitching is applied thereto. As mentioned above, the simultaneous stitching on the central portions can be identical to the stitching along the left and right sides  18  and  20 , or it may be identical but applied with a larger spacing between stitches, or be different stitching. 
     Blanks  10  of stitched material are separated from rolled fabric  28  when the fabric is cut along cut lines  32 , shown in  FIG. 3 . The proportions shown in  FIG. 3  are suited to produce mattress covers of the type illustrated in  FIGS. 1A, 1B and 1C  wherein dimension X is smaller than one half of dimension Y. Each blank between lines  32  is mounted while still under tension onto a jig holding dimensions Y and Z corresponding to the top of the mattress between fold lines  24  flat. Cut lines  22  are cut or slit, preferably before lines  32  are cut, while fabric  28  is still moving in the MD. Alternatively, cut lines  22  are made after blanks  10  between cut lines  32  are cut from fabric  28  and mounted on a jig. Panels  14  and  16  are folded down and the protruding free ends  26  are wrapped around the ends and attached as shown in  FIG. 1B . The setup of  FIGS. 2A and 2B  wherein the free ends  26  can reach across to each other can alternately be achieved by increasing the extra length X of  FIG. 3  so that it equals or exceeds one half of length Y. 
     In another preferred embodiment, the free edges  26  are maintained under stretched condition and are sewn together and/or to top/bottom panels  14 ,  16 , before elastic materials  30  are relaxed. Hence, the entire mattress cover or sheet is manufactured by one set of machineries at one continuous process. Relaxed elastic materials do not have to the re-tensioned or re-stretched before being attached to the blanks. In one exemplary embodiment, free edges  26  are also clamped to maintain the tension and the top and bottom clamped edges  26  are rotated toward each other and sewn or stitched together or to end panels  14  or  16 , before the tension in elastic materials is released. 
     Elastic stitching can be purely elastic or elastomeric, or a combination of elastic and bulkable yarns that are directly stitch-bonded to panels  18  and  20 , and optionally to the central panels  12 ,  14  and/or  16  as well. Suitable elastic stitch-bonded yarns and stitch-bonded patterns are discussed in U.S. Pat. Nos. 5,603,132; 5,308,674; 5,127,115; 5,636,393; 5,308,674; 5,187,952; 5,247,893; 6,272,701; and 6,883,193. These references are incorporated herein by reference in their entireties. 
     As discussed above, fabric  28  can be a simple woven, knit or non-woven layer. Fabric  28  can also be a composite of two or more layers, including but not limited to, an absorbent layer, a water-proof membrane, a film, or a water-resistant fabric layer. As it is also discussed above additional narrower layers  40  with a width Y, added under or over panel  12  and end panels  14  and  16  may be single layers or composites of two or more layers. 
     In another aspect of the present invention, blanks  10  could be rotated about 90° so that the end panels become the left and right panels, and the left and right panels become the end panels. In this variation blanks  10  would be in a portrait orientation instead of the landscape orientation shown in  FIGS. 1-3 . As used herein the terms left, right or end are terms relative to the orientation of the blanks. 
     While it is apparent that the illustrative embodiments of the invention disclosed herein fulfill the objectives stated above, it is appreciated that numerous modifications and other embodiments may be devised by those skilled in the art. One such modification is that free edges  26  can be attached to each other and/or to panels  14  and  16  by zippers, buttons/button holes, Velcro fasteners or other known forms of attaching textiles to each other. Therefore, it will be understood that the appended claims are intended to cover all such modifications and embodiments, which would come within the spirit and scope of the present invention.