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 . as shown in fig3 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 fig1 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 . 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 . as shown in fig3 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 ( fig1 ) 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 fig1 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 . 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 . fig2 ). 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 fig1 . 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 fig1 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 . 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 . referring to fig3 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 : a . the top and bottom panels 14 , 16 are cut to 53 ″× 29 ″; b . the side panels 18 , 20 are cut to 49 ″× 6 . 5 ″; c . the first end panel 22 is cut to 33 ″× 10 . 25 ″; and d . the second end panel 24 is cut to 29 ″× 6 . 5 ″. 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 ″. 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 . 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 fig3 ) 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 fig3 ) 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 . 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 . 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 . 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 . 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 .
a crib sheet that form fits on a mattress . 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 defined between lateral edges extends laterally through the sidewall portion . 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 .