Bed sheet system

摘要

A bed sheet system for application to a mattress having rounded corners, a nominal mattress width between opposite sides of mattress, a nominal mattress length between opposite ends of the mattress, and a nominal mattress height. The bed sheet system includes a bottom flat fitted sheet and standard dimension top unfitted sheet. The unfitted top sheet may be attached by fastening along the foot-hem to the bottom sheet, or not attached with placement head-mark and size-mark, and corners marks to guide properly centered position with proper amount overhang on the sides and ends. The bottom flat-fitted sheet includes a rectangular material without cutouts or with cutouts at corners of the sheet on intersection of reference lines, and which according to the calculation, has geometric layout including a central part designed according to calculations to cover top of mattress, where length and width of central part are smaller two inches, than nominal length and width of mattress, because arches as ⅛ of circle with approximately five inches radius are smaller one inch compere to five inches radius of mattress's corners. Because the physical edge of mattress is eight inches (2π×5″ radius of mattress/4=8″) smaller than sum of nominal rectangular mattress' dimensions, the central part has been established by calculation as rectangular, which perimeter is equal curved border of mattress and is depicted in reference lines. The central part is surrounded by two ends and two sides for overhang ends and sides of mattress, which heights are one inch bigger than height of mattress designed for one inch of reinforced hem on the perimeter of bottom fitted sheet for the placement of fasteners at the tension points as offset to the reference lines, and when pulling with force together the fasteners causes reinforced hem to slip under corners of mattress, and keeps the sheet on the mattress without slipping off. The size and dimension of a fitted bed sheet are determined for each of various sizes of mattress by calculation for the central part and height of the mattress with addition one inch for the reinforced hem.

主权项

1. A bed sheet system for application to an elastic mattress, the mattress having a size; a mattress top having a perimeter; four rounded mattress corners at corners of the mattress, each mattress corner having a radius; a nominal mattress width between opposite sides of the mattress on a transverse axis of the mattress; a nominal mattress length between opposite ends of the mattress on a longitudinal axis of the mattress; and a nominal mattress height defined by the distance between a top and a bottom of the mattress, the bed sheet system comprising:
a bottom fitted sheet comprising a rectangular non-elastic fabric panel configured for covering the mattress and exerting compression on the mattress when installed thereon; and a top unfitted sheet comprising a rectangular fabric panel for overlying the fitted sheet when installed thereon for covering the mattress and the fitted sheet; wherein the fitted sheet construction comprises four crease reference lines located to be parallel to the longitudinal and transverse axes of the mattress and located one inch in distance from rectilinear edges of the mattress and parallel to the longitudinal and transverse axes of the mattress when installed on the mattress, the four crease reference lines defining on the fitted sheet a rectangular unitary central part, two ends, and two sides and four corners, the corners being removable or non-removable; wherein two of the crease reference lines define width reference lines, each width reference line of the central part located when the fitted sheet is applied to the mattress so as to be parallel to one of the sides of the mattress and spaced a distance inside a side of the mattress an amount equal to at least the difference of the [radius of mattress minus (π·radius of the mattress/4)], and two of the crease reference lines define length reference lines, each length reference line of the central part located when the sheet is applied to the mattress so as to be parallel to one the sides of the mattress and spaced a distance inside an end of the mattress an amount of at least the difference of the [radius of mattress minus (π·radius of the mattress/4)]; wherein the rectangular central part of the fitted sheet is dimensioned to have a width two inches less than the nominal width of the mattress and a length two inches less than the length dimensions of the mattress, the rectangular central part having a perimeter equal to the perimeter of the mattress top, the rectangular central part defined and confined by the reference lines, the central part's extended crease reference lines defining three alternative fastener positions for location of fasteners with a fastener being provided at each fastener position for installation thereon during fitting of the fitted sheet to the mattress; wherein the fitted sheet is configured in size for each size of mattress by calculation of the central part as a rectangle having sides that are each two inches smaller than corresponding sides of the mattress plus two ends-wings and two sides-wings, which equal the nominal height of the mattress plus one inch for the reinforced perimeter-hem; wherein the three alternative fastener positions on ends of the reinforced perimeter, enclosed between reference lines, defined by the extended crease reference lines of central part, are located adjacent a corner of the mattress and located to be first point one-inch interior and second point and a third point each being one inch apart respectively, for the adjustment of the tension, interior of one of the width reference lines or interior of one of the length reference lines; wherein so when the fasteners are installed at the fastener positions the fitted sheet is snugly fit onto the top of the mattress and applies pressure to curved edges of the top of the mattress proximate the corners to transform the curved edges to a rectangular shape corresponding to the central part of the fitted sheet, which creates a primary compression on the top of the mattress and a secondary tension at the fastener positions to provide additional tension around the mattress to cause lower edges of the fitted sheet to slip under the mattress to aid in maintaining the fitted sheet in compression on the mattress and aid in inhibiting the fitted sheet from slipping off the mattress; wherein a bottom fitted sheet including a head-marker, a size marker defined on a head end of the top fitted sheet at a longitudinal axis thereof, and demarcated corner marks of the underlying mattress and located to overlie the intersection of crease reference lines to facilitate positioning the bottom fitted sheet on the mattress in centered position; and the top unfitted sheet being configured for overlying the fitted sheet when installed thereon for covering the mattress and the fitted sheet, the top unfitted sheet comprising a rectangular panel of fabric with a doubled edge on a foot hem thereof, and having layout guiding thereof for the transverse and longitudinal axes, comprising a head-marker and size-marker defined on a head end of the top unfitted sheet at longitudinal axis thereof, and corner marks of the underlying mattress defined on the top unfitted sheet and located to overlie the crease reference lines of the fitted sheet when the top unfitted sheet is laid over the unfitted sheet to facilitate positioning of the top unfitted sheet in a centered position on the mattress so that with substantially equal portions of the unfitted sheet overhang each side of the mattress; wherein the top unfitted sheet is attached along the foot-hem thereof to the underlying fitted sheet foot hem by a fastening row having opposite ends each located a distance of four inches from the length reference lines of the fitted sheet, wherein the fastening row is either sewed to the unfitted sheet or attached thereto with detachable fasteners.