Patent Document

FIELD OF THE INVENTION  
         [0001]    This invention pertains to sheets for mattresses such as for beds, cribs or playpens and the like.  
         BACKGROUND OF THE INVENTION  
         [0002]    Conventional crib sheets comprise a single sheet or panel of fabric covering the top of the crib mattress. The single sheet is held on the mattress by elastic sheet corners that fit snugly on the corners of the mattress. As described in U.S. Pat. No. 6,067,677 to Reen et al., this design has significant drawbacks, notably that the sheet can be pulled off by an infant and the infant can become entangled amidst the unraveled sheet. The &#39;677 patent describes an attempt to encapsulate the crib mattress utilizing an elastic mattress entrance opening through the sheet and a Velcro flap that wraps over the opening and attaches to the bottom portion of the crib sheet. Another somewhat similar arrangement for a playpen mattress is shown in U.S. Pat. No. 5,642,540 which also has a flap that is secured to the bottom underside panel of the sheet. While these patents disclose various attempts to prevent unraveling of crib sheets, these patents have other drawbacks that have been discovered by the present inventor and which are remedied by the present invention.  
         BRIEF SUMMARY OF THE INVENTION  
         [0003]    The present invention is directed toward a sheet adapted to be form fitted on a mattress that overcomes drawbacks existing in the prior art while also preventing unraveling of the sheet. The sheet comprises generally rectangular top and bottom portions that are spaced apart generally parallel when form fitted on the mattress. A sidewall portion extends around the periphery of the top and bottom portions to define four sides. The sidewall portion is generally perpendicular between the top and bottom panels when form fitted on the mattress. A mattress opening extends laterally through the sidewall portion and is defined between lateral edges. The mattress opening extends along the length one side and at least partially along two adjacent sides. Fasteners on the lateral edges surrounding the mattress opening are operable to open and securely close the mattress opening.  
           [0004]    It is an advantage according to one aspect of the present invention that the bed sheet is reversible and either the top side or the bottom side may be used on the top surface of the mattress. In either position, the mattress opening and fastening mechanism therefore is still hidden at the side or end of the mattress. The reversibility feature is particularly advantageous for messes made by infants, because the mattress can simply be turned over to expose the clean bottom side along the top. It will be appreciated that this is particularly helpful for example in the middle of the night when it would be arduous and time consuming to completely remove soiled mattress sheet and replace it with a clean mattress sheet. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]    [0005]FIG. 1 is an exploded perspective view of a crib sheet according to a preferred embodiment of the present invention for a crib mattress.  
         [0006]    [0006]FIG. 1 a  is an enlarged view of a portion of FIG. 1.  
         [0007]    [0007]FIG. 2 is a perspective view of the crib sheet shown in FIG. 1 form fitted on a crib mattress.  
         [0008]    [0008]FIG. 3 is an exploded assembly drawing illustrating the various sheet panels of fabric material and how the sheet panels are sewn together. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0009]    A preferred embodiment of the present invention has been illustrated in the drawings as a crib sheet  10  for use with a crib mattress  12 . In a preferred embodiment, the crib sheet  10  is made of flexible fabric material and is constructed from multiple panels that are cut preferably utilizing patterns.  
         [0010]    As shown in FIG. 3, the crib sheet comprises many different cut fabric pieces that are sewn or otherwise secured together, including a top panel  14 , a bottom panel  16 , a pair of side panels  18 ,  20 , and a pair of end panels  22 ,  24 . As shown, the top and bottom panels  14 ,  16  are generally rectangular in shape and may have arcuate corners  26  that closely conform to the shape of the crib mattress  12 . As shown in FIGS. 1 and 3, the side panels  18 ,  20  have top and bottom edges that are sewn to side edges on the top and bottom panels  14 ,  16  along horizontal stitch seams  28 . The side panels  18 ,  20  extend generally perpendicular between the top and bottom panels  14 ,  16  when the sheet  10  is form fitted on the mattress  12 . The end panels  22 ,  24  also have top and bottom edges that are sewn to end edges on the top and bottom panels  14 ,  16  along the horizontal stitch seams  28 . The end panels  22 ,  24  have side edges that are sewn to corresponding side edges of the side panels  18 ,  20  along vertical seams  30 . The end panels  22 ,  24  extend generally perpendicular between the bottom panels  14 ,  16  in a vertical direction and generally perpendicular between the side panels  18 ,  20  in a horizontal or lateral direction when the sheet  10  is form fitted on the mattress  12 .  
         [0011]    The construction of the sheet  10  described above provides the sheet with rectangular top and bottom portions and a vertical sidewall that transverses around the rectangular periphery of the top and bottom portions to define four different sides. It will be appreciated that the actual construction of the generally rectangular box shaped structure of the mattress sheet  10  can be made of more or fewer different cut pieces with stitch seams located in other locations, but such a construction still results in sidewall, top and bottom portions.  
         [0012]    As shown in FIG. 3, the first end panel  22  is cut apart along a lateral line to provide upper and lower segments  32 ,  34  to define a mattress opening  35  (FIG. 1) between upper and lower lateral edges  36 ,  38 . The upper and lower lateral edges  36 ,  38  preferably overlap to provide overlapping flaps  40 ,  42  that may partially or fully conceal the mattress opening  35 . Fasteners shown in the form of snap tape strips  44 ,  46  are provided along the upper and lower lateral edges  36 ,  38  and more specifically on the overlapping flaps  40 ,  42  to provide a means to open and close the mattress opening  35 , as shown in FIGS. 1 and 2. The snap tape strips  44 ,  46  are sewn to the overlapping flaps  40 ,  42  along horizontal stitch seams  48 . Although snap tape strips  44 ,  46  are shown as one form of fastener, it will be appreciated that other fasteners may be used including hook and loop fasteners, a Velcro strip, buttons/button openings, and/or zippers.  
         [0013]    It is an aspect of the disclosed embodiment that the first end panel  24  and therefore also the mattress opening  35  extend around the two opposing corners  26  to form part of the two sides adjacent the end of the crib sheet  10 . Specifically, the end panel  24  includes opposed lateral end portions  47  that wrap around the corners  26  (see e.g. FIG. 2). This provides the mattress opening  35  with sufficient size to allow for manually sliding of the mattress  12  through the mattress opening  35  when open as shown in FIG. 1. No elastic material is needed to make the opening  35  expandable or retractable and advantageously the sheet  10  may be free of elastic material. The mattress opening  35  is of a large enough size when open as shown in FIG. 1 such that it need not be expanded to insert or remove the mattress. This also allows the vertical seams  30  along the vertical edges of the first end panel  22  to stitch the overlapping flaps  40 ,  42  together and provide for a strong structure and a clean appearance.  
         [0014]    An advantage of the disclosed embodiment is that the fastening strips  44 ,  46 , the mattress opening  35  and the overlapping flaps  40 ,  42  are all provided along the sidewall between the top and bottom panels  14 ,  16 . The top and bottom panels  14 ,  16  are therefore free of fastening devices and can both be used as a top surface for the mattress  12 . This is particularly advantageous when an infant makes a mess, for example in the middle of the night. The mattress  12  and the sheet  10  form fitted thereon simply can be flipped over to provide the bottom panel  16  as the clean top surface, while the soiled top panel  14  is disposed along the bottom surface and therefore not in use.  
         [0015]    Referring to FIG. 3, a preferred method of constructing the crib sheet  10  for a standard 52″×28″×5″ or 6″ thickness comprises first cutting the individual panels  14 ,  16 ,  18 ,  20 ,  22 ,  24  from fabric material such that:  
         [0016]    a. the top and bottom panels  14 ,  16  are cut to 53″×29″;  
         [0017]    b. the side panels  18 ,  20  are cut to 49″×6.5″;  
         [0018]    c. the first end panel  22  is cut to 33″×10.25″; and  
         [0019]    d. the second end panel  24  is cut to 29″×6.5″.  
         [0020]    As evident from the dimensions above, the first end panel  22  may be cut to be larger vertically and horizontally than the second end panel  24 , to allow sufficient fabric to provide for the oversized mattress opening  35  and securing of the fasteners strips  44 ,  46 . The fastener tape (in which the individual strips  44 ,  46  are connected) is also cut to a length of 33″.  
         [0021]    The larger first end panel  22  is folded in half lengthwise and cut down the center to form two equal halves (e.g. the upper and lower segments  32 ,  34 ). Each segment  32 ,  34  is given a ¾ inch double hem along the cut side. One segment has the double hem facing up with the other segment having the double hem facing down (both double hems are face down if using a zipper). The individual strips  44 ,  46  of the fastener tape are then placed on each double-hemmed section of each segment  32 ,  34  and are stitched in place using a zipper foot. Once the tape (e.g. the individual strips  44 ,  46 ) is applied, the two segments  32 ,  34  are fastened together by closing the snaps on the snap strips  44 ,  46 , thereby forming a complete section. The short ends are then stitched with a ½ inch seam allowance permanently securing the fastener of choice in place. This completes the first end panel  22  to provide for the mattress opening  35 .  
         [0022]    The opposed ends of the first end panel  22  are then stitched to each side panel  18 ,  20  along continuous vertical seams  30  (location of seam among adjacent parts being indicated in FIG. 3) with a ½ inch allowance. The smaller second end panel  24  is stitched to the side panels  18 ,  20  along additional vertical seams  30  at the side opposite the first end panel  22  with a ½ inch allowance. This completes and forms a unitary sidewall. The top edge of the sidewall is stitched to the top panel  14  along one horizontal seam  28  with a ½ inch seam allowance. The bottom edge of the sidewall is stitched to the bottom panel  16  along another horizontal seam  28  (location of seam among adjacent parts indicated in FIG. 3) with a ½ inch seam allowance. In stitching the sidewall and the top and bottom panels, the material is eased in around the arcuate corners  26 .  
         [0023]    The completed sheet  10  has measurements of 52″×28″×5.5″. The sheet will fit the standard 52″×28″ crib and toddler bed mattresses with either a 5″ or a 6″ thickness. Other dimensions may be used for other types of mattresses such as playpen mattresses or other bed mattresses where the features and advantages of the present invention are desired.  
         [0024]    The examples discussed above further illustrate the invention but, of course, should not be construed as in any way limiting its scope. All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.  
         [0025]    The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (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 invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.  
         [0026]    Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. 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 invention to be practiced otherwise than as specifically described herein. Accordingly, this invention 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 invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Technology Category: 1