Abstract:
The formation of wrinkles in bed sheets used on mattresses of the type having elevated side bolsters and the tendency of the sheets to come off when the mattress is articulated are reduced through the use of a fitted sheet having conforming pockets receiving the side bolsters. Stabilization of the upper sheet surface by the pockets is augmented in some embodiments through use of a stitch line placed along a seam on the inside of the pockets and/or by un-pocketed spans of the upper surface of the sheet connecting directly to an elastically retained skirt.

Description:
CROSS-REFERENCE RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. provisional application 61/138,789 filed Dec. 18, 2008 and hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to mattresses used in patient care settings for pressure management and wound care, and in particular to an improved mattress/sheet combination. 
         [0003]    The importance of mattress construction in preventing or treating pressure ulcers for patients who are mostly or completely bedridden or who are recovering from medical procedures is well recognized. 
         [0004]    Often it is desired to provide for raised perimeter sections (bolsters) on the mattress to improve both safety and comfort by guiding the patient away from mattress edges. A standard flat or fitted/bottom sheet or deep-pocketed sheet may be used with such mattresses by laying it over the raised perimeter portions and tucking it in loosely around the mattress to prevent undue compression of the raised perimeter portions or a “spanning” of the sheet between the raised perimeter portions. 
       SUMMARY OF THE INVENTION 
       [0005]    The present inventors have determined that standard sheeting when used with raised perimeter mattresses can create sheet wrinkles that produce uncomfortable pressure points for the patient. The present invention addresses this problem by means of a fitted sheet having corresponding pockets for receiving the raised perimeter portions. In one embodiment, the raised peripheral portions extend only part way along the length of the mattress leaving a center section without raised portions. The sheet across this center section and at mattress ends serves to stabilize the sheet of the pockets further helping to eliminate wrinkles that might be expected caused by the pocket&#39;s interference with drawing of the sheet tightly across the top of the bed. A seam may be positioned along the inside edge of the pockets, stiffening this edge further against pulling inward to the center of the bed, permitting wrinkles. The ability to produce a fitted sheet for this mattress type further greatly improves retention of the sheet on the mattress when the resident is repositioned, moved into and out of the bed or the bed is articulated. 
         [0006]    Specifically, the present invention provides a fitted sheet for a mattress of a type having a substantially planar upper surface adapted to support a patient&#39;s body as flanked by left and right side bolsters rising from the upper surface, the bolsters extending along at least a portion of the length of the mattress. The fitted sheet includes a skirt having a lower elastic edge, the skirt sized to extend around the periphery of the mattress with the lower edge position positioned proximate to a lower surface of the mattress to elastically grip the same. A top portion of the sheet is sized to cover and lie substantially flat against the upper surface of the mattress while joining with an upper edge of the skirt at a foot and head of the top portion corresponding to a foot and head of the mattress when the fitted sheet is installed on the mattress. Bolster pockets join on outer edges with the skirt and on inner edges with the top portion, the bolster pockets including textile end elements attached, by stitching, to bolster pockets to define pocket corners and ends of the bolsters so that the bolster pockets substantially conform to the bolsters when the fitted sheet is installed on the mattress. 
         [0007]    It is thus a feature of at least one embodiment of the invention to provide tailored pockets that may grip the bolsters to reduce wrinkling of the sheet. 
         [0008]    Each bolster of the mattress may have a reduced height portion dividing the bolster into upper and lower full height portions and the top portion may join with an upper edge of the skirt at a left and right of the top portion after the top portion passes through the reduced height portion of the left and right side bolsters when the fitted sheet is installed on the mattress. The bolster pockets for the upper and lower full height portions may include additional textile end elements attached by stitching to the bolster pockets to define pocket corners at opposed ends of the upper and lower full height portions so that the bolster pockets substantially conform to the upper and lower full height portions of the bolsters when the fitted sheet is installed on the mattress. 
         [0009]    It is thus a feature of at least one embodiment of the invention to provide multiple pockets of shorter length which provide improved stabilization along the length of the pocket and direct attachment of the top portion to the skirt providing conventional stabilization. 
         [0010]    At least the top portion may be constructed of a breathable textile passing air through pores between textile fibers, for example a woven fabric such as a blend of cotton and polyester. 
         [0011]    It is thus a feature of at least one embodiment of the invention to provide the advantages of the present invention in a material that may directly contact the patient. 
         [0012]    The fitted sheet elements of the top sheet, bolster pockets, and skirt are constructed of a textile having a weight less than 8 ounces per square yard. 
         [0013]    It is thus a feature of at least one embodiment of the invention to provide stabilization for relatively lightweight fabrics that cannot rely on inherent fabric stiffness to resist wrinkles. 
         [0014]    The textile end elements may have trapezoidal areas attached to other elements of the fitted sheet by stitching along at least two edges of the trapezoidal area. 
         [0015]    It is thus a feature of at least one embodiment of the invention to provide bolster pockets that are closely tailored to the bolsters for improved stabilization of the sheet. 
         [0016]    When the sheet is fitted to the mattress, each bolster pocket may include: an upper horizontal part extending along at least a portion of the length of the sheet, an inwardly facing sloped part extending along the portion of the length of the sheet and attached at an upper edge to the upper horizontal part; an outwardly facing vertical part extending along the portion of the length of the sheet and attached at an upper edge to the upper horizontal part; and opposed head and foot panels attached to at least one of the upper planar part, inwardly facing sloped part, and outwardly facing vertical part by stitching; and the inwardly facing sloped part may attach to the top portion of the fitted sheet by stitching. 
         [0017]    It is thus a feature of at least one embodiment of the invention to provide a reinforcing seam along an inner edge of the bolster to resist wrinkling. 
         [0018]    The stitching may join at least three layers of textile in areas where the stitching is exposed to the patient. 
         [0019]    It is thus a feature of at least one embodiment of the invention to provide a build up of textile thickness under the stitching such as reduces the perceived roughness of the stitching to the patient. 
         [0020]    The stitching may be a contrasting color from the textile of the sheet. 
         [0021]    It is thus a feature of at least one embodiment of the invention to provide a clear visual indication of the fitted nature of the sheet when the sheet is stored between washings. 
         [0022]    The top sheet may have an orientation providing a greatest stretch of the textile across the width of the mattress. 
         [0023]    It is thus a feature of at least one embodiment of the invention to orient the fabric to further reduce wrinkling and remain on the mattress during resident repositioning, bed entry or exit, and bed articulation. 
         [0024]    These particular objects and advantages may apply to only some embodiments falling within the claims, and thus do not define the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0025]      FIG. 1  is a top view of a sheet of the present invention fit to a corresponding mattress; 
           [0026]      FIG. 2  is an end view of the sheet of  FIG. 1 ; 
           [0027]      FIG. 3  is a perspective view of the sheet of  FIGS. 1 and 2  showing stitched seams with the small x&#39;s; 
           [0028]      FIG. 4  is a bottom view of the sheet of the present invention as it wraps around the mattress; 
           [0029]      FIG. 5  is a an exploded diagram of the components of the sheet for one corner of the sheet; and 
           [0030]      FIG. 6  is a cross-sectional view through a stitched patient-contacting seam. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0031]    Referring now to  FIGS. 1 ,  2  and  3 , the present invention provides a fitted sheet  10  fitting to a mattress having substantially identical upper dimensions. Generally, when the sheet  10  is fit to the mattress, the sheet  10  presents a horizontal, cross-shaped, planar upper surface  12  having upper and lower arms  9  and  13  terminating at edges  14  and  16  of the upper surface of the mattress at the head and foot of the mattress respectively, and right and left arms  19  and  21  terminating at edges  18  and  20  of the upper surface of the mattress on the right and left side of the mattress respectively. The upper and lower arms  9  and  13  have a width slightly less than the width of the mattress, in one embodiment about 6 inches less than the width of the mattress, and the left and right arms  19  and  21  have a length of about twenty-six inches in one embodiment conforming to a particular commercially available mattress. 
         [0032]    A skirt  40  extends around the periphery of the mattress covering the height of the mattress and is formed of side panels  28  at the left and right sides of the mattress, and end panels  30  at the head and foot ends of the mattress. Edges  20  and  18  of left and right arms  19  and  21  are attached directly to upper edges of side panels  28  by stitching. 
         [0033]    At the corners of the plane defined by the upper surface  12 , fitting between the pairs of arms  9  and  19 ,  9  and  21 ,  13  and  21 , and  13  and  19  of the upper surface  12  to complete a rectangular boundary of the upper surface of the mattress, are upwardly extending bolster pockets  22   a - d  receiving corresponding raised peripheral portions of the underlying mattress. In one embodiment, the bolster pockets extend upward by about three inches. 
         [0034]    The downwardly open bolster pockets  22  each include an inward sloping surface  24  extending parallel to a length of the sheet  10  and facing the patient, and an upper plateau  26  joined at one edge to an upper edge the inward sloping surface  24  and being generally parallel to the upper surface  12  while elevated therefrom. An outer vertical surface of each pocket  22  is provided by the side panel  28  connecting to a corresponding outer edge of the plateau  26 . In one embodiment, the side panel  28 , upper plateau  26 , and inward sloping surface  24  are a single continuous panel of textile without stitched seams. In one embodiment, the joining of the inward sloping surface  24  to the edges of the arms  13  and  9  is by means of stitched seams  29  that stiffen these edges to prevent wrinkling. 
         [0035]    End panels  30  at the head and foot of the sheet extend vertically in trapezoidal tabs  33  to provide end portions of the bolster pockets  22  at the head and foot respectively of the mattress. Finally, panels  32  provide trapezoidal textile elements filling the space between the upper surface  12 , the side panels  28 , the plateaus  26 , and the inward sloping surface  24 , at the inner opposed ends of the bolster pockets  22  flanking the arms  19  or  21 . The trapezoidal tabs  33  and the panels  32  attached to the side panels  28 , plateaus  26 , and inward sloping surfaces  24 , to form corners, being a joining of three fabric elements along pairwise edges that conceptually intersect at a single corner point as moderated by the realities of flexible fabric. 
         [0036]    Referring momentarily to  FIG. 4 , the end panels  30  and side panels  28  that form the skirt  40  have a lower edge that may be drawn under the mattress by an elastic cord  41  sewn to the edge of the skirt (for example as captured within a folded back seam). This skirt  40  provides a peripheral tensioning of the sheet  10  in the manner of a conventional fitted sheet. 
         [0037]    The cross shape of the upper surface  12  and its tension, applied through the arms  19  and  21 , and  9  and  13 , may stabilize the sheet  10  and eliminate wrinkles of the type that could be formed with a single planar sheet fitted to this mattress type. The arms  19  and  21  in tension resist further movement of the upper surface  12  drawn by the tension of the skirt  40  that might lift the upper surface  12  of the sheet  10  into a spanning configuration between the bolsters, while the arms  9  and  13  in tension draw wrinkles out from the intersection between inward sloping surfaces  24  and the upper surface  12 . The seam  29  running along the inside of the bolster pockets  22  and anchored in tension at the ends of the bolster pockets  22  also provides resistance to wrinkling by better retaining the edges of the arms  9  and  13  outward against the bolsters. 
         [0038]    Referring momentarily to  FIG. 5 , construction of the sheet  10  may employ four constituent continuous textile elements: top element  42  (duplicated once to provide the upper surface  12 ), end element  44  (duplicated twice to provide the end panels  30 ), side element  48  (duplicated twice to provide the left and right side panels  28  and the upper plateaus  26  and inner sloped surfaces  24  of the pockets  22 ), and cap element  50  duplicated four times to provide panels  32 ). These elements are joined by stitching at their interface with the other elements. 
         [0039]    Referring to  FIG. 6 , the stitching  58  of each of the seams  29  may be done so that exposed ends of the stitching  58  on a side  62  exposed to the patient will pass through at least three layers of textile  64  such as provides a perception of greater softness in the stitching to the patient. Decorative stitching with thread of contrasting color provides an indication of the special qualities of the sheet in its folded condition to distinguish it from regular sheets. Generally, the material of the sheet may be 50% cotton 50% polyester having a weight of approximately 5.07 ounces per square yard and less than 8 ounces per square yard and a thickness of approximately 0.019 inches and is preferably a woven or nonwoven polyester or cotton polyester that is breathable. The material of the upper surface  12  may be oriented to provide the greatest stretch across the width of the mattress (i.e. in a direction parallel to that extending between arms  19  and  21 ). 
         [0040]    Referring again to  FIG. 3 , it will be understood that certain features of the present invention, including the pockets  22  and stiffening seams  29 , may also be employed with the mattress having a continuous left and right side bolster by the simple expedient of merging pockets  22   a  and  22   c  and pockets  22   b  and  22   d  with the elimination of arms  19  and  21 . Further it will be understood that arms  19  and  21  may surmount, without the need for pockets, a reduced height section of such continuous bolsters between pockets  22   a  and  22   c  or  22   b  and  22   d.  As used herein “reduced height portion” of a bolster should be considered to include a portion having a lower height than other portions of the bolster or even zero height (that is even with the upper surface  12 ). 
         [0041]    It should be understood that the invention is not limited in its application to the details of construction and arrangements of the components set forth herein. The invention is capable of other embodiments and of being practiced or carried out in various ways. Variations and modifications of the foregoing are within the scope of the present invention. It also being understood that the invention disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present invention. The embodiments described herein explain the best modes known for practicing the invention and will enable others skilled in the art to utilize the invention.