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`BEDGEAR 1022
`IPR of U.S. Pat. No. 8,402,580
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`U.S. Patent
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`Dec. 26, 2000
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`6,164,092
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`FIG. 1
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`FIG. 2
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`6,164,092
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`1
`KNITTED FABRIC HAVING ELASTOMERIC
`YARN
`
`BACKGROUND OF THE INVENTION
`
`invention relates to an improved knitted
`The present
`fabric, and in particular to a knitted sheeting material made
`of a poly-cotton yarn and elastomeric yarn which retains its
`shape,
`is stretchable, versatile, and longer lasting than
`cotton/polyester sheets.
`Currently, it is known in the art to provide plain woven
`and knitted sheets to institutions such as hospitals, nursing
`homes, rest homes and the like. Most commonly,
`these
`sheets are woven, rather than knitted, and are made from
`only a blend of polyester and cotton yarns.
`The fitted or contoured sheets made from “conventional”
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`woven fabric generally do not fit more than one mattress size
`and are difficult to fit on mattresses having foam comfort
`overlays. Accordingly,
`institutions using conventional
`woven contour or fitted sheets must maintain sheets of
`several sizes in order to fit all
`the bed sizes within the
`institution.
`
`Another common problem with conventional woven fitted
`sheets is that they “pop off” the mattress rather easily. Fitted
`sheets generally pop off the mattress because they are either
`too small for the mattress or have difficulty adhering to the
`mattress when the head or foot of the bed is raised or
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`lowered. A common problem associated with conventional
`sheets that are knitted from polyester-cotton blend strands is
`that they have a tendency to wear out over time due to
`“pinholing.” Pinholing results from individual yarns snag-
`ging and breaking or from fatigue of fibers due to repeated
`washing. When the pinholes get too large or too numerous,
`the sheets are taken out of service. A third problem with
`conventional woven and knitted contour sheets is shrinkage.
`After washing they become smaller and thus more difficult
`to fit over a mattress. The corner seams may rip permanently
`due to the bedmaking staff having to pull very hard to stretch
`the sheets onto the mattress. Finally, in institutional settings,
`these same prior woven or knitted sheets tend to “bunch”
`from the raising or lowering of the bed or bunch when a
`patient repositions one’s self in the bed. This bunching can
`lead to discomfort due to skin shear and pressure points,
`which is also the common cause of skin problems in older
`patients.
`The present invention provides an improved fabric which
`addresses all of the problems previously outlined by knitting
`together two yarn types, at least one yarn type being an
`elastomeric or hyper-elastic yarn. In one embodiment, the
`first yarn type is comprised of a blend of natural and
`synthetic fibers, preferably a blend of cotton and polyester
`(hereinafter “poly-cotton”), and the other yarn is comprised
`of an elastomeric or hyper-elastic fiber such as spandex. This
`unique blend of knitted poly-cotton and elastomeric yarns
`creates a knitted fabric having increased shape retention,
`versatility, and an increased useful life over that of the
`conventional or traditionally knitted or woven fabric sheets.
`The elastomeric yarn allows the fabric to stretch more than
`traditional poly-cotton sheets. This increased stretching abil-
`ity allows for easier installation of the fitted sheets on the
`mattress and allows the creation of one size of fitted sheet to
`fit all normal sized health care mattresses, with or without
`foam comfort overlays. The elastomeric yarn also allows the
`sheets to adhere better to the mattress. The elastomeric yarn
`gives the sheets the continued resilience to attempt to “pull”
`the fabric back into its resting shape even when adhered to
`the mattress. Further, the elastomeric yarn and poly-cotton
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`yarn blend creates a more resilient fabric, which is resistant
`to snagging, fiber fatigue, pinholing, and which increases the
`useful life of the fabric. Further, the elasticity of the present
`invention allows the sheet to “give” with a patient when the
`patient is repositioning. Likewise, the elasticity of the sheets
`allows them to stay taut when the bed is raised or lowered,
`thereby reducing the occurrence of “bunching up” under the
`patient. This reduced bunching effect in turn promotes better
`skin care by reducing skin shear and pressure points.
`While the preferred embodiment of this invention
`addresses problems most associated with fitted or contoured
`sheets,
`it is recognized that other products such as crib
`sheets, pillow cases, stretcher sheets, flat sheets, fitted flat
`sheets, and sheets for sale to the retail market, may be
`created from this inventive fabric.
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`SUMMARY OF THE INVENTION
`
`The present invention solves many problems present in
`the prior art by providing a knitted fabric comprised of two
`yarn types wherein at least one yarn type is made of an
`elastomeric fiber and the other yarn type is made of a
`substantially non-elastic fiber. In the preferred embodiment,
`one yarn type is a blend of polyester and cotton and the other
`yarn type is spandex. This overall blend of spandex and
`poly-cotton fibers creates a knitted fabric having resilience,
`elasticity and versatility beyond that of a traditional poly-
`cotton blend fabric. This knitted fabric can then be used to
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`produce sheeting materials, such as fitted contour sheets,
`which retain shape better, are more easily handled, and have
`a greater life that standard poly-cotton blend sheets.
`Accordingly,
`it
`is the principal object of the present
`invention to provide a fabric which, when made into fitted
`bed sheets, adheres to a mattress and does not easily pop off
`when the head or foot end of a mattress is raised or lowered.
`
`Another object of the present invention is to provide a
`fabric which can be made into a single size fitted sheet that
`fits all normal health care mattresses, with or without foam
`comfort overlays.
`A further objective of the present invention is to provide
`a fabric which is resistant to snagging, fiber fatigue, and
`pinholing, which in turn increases the useful life of a sheet,
`crib sheet, pillowcase, stretcher sheet, or fitted contour sheet
`made of the fabric.
`
`An additional object of the present invention is to provide
`a fabric which, when made into bed sheets and used in an
`institutional setting, “gives” with patients’ movements when
`repositioning and stays taut when used as a sheet when the
`bed is raised or lowered. The ability of the sheets to give and
`stay taut promotes especially good skin care, and thereby
`reduces skin sheer and pressure points, which are the most
`common causes of skin problems in older patients.
`These and other objects and advantages of the present
`invention will be clarified in the following description of the
`preferred embodiment in connection with the drawings, the
`disclosure and the appended claims, wherein like reference
`numerals represent like elements throughout.
`DESCRIPTION OF THE DRAWINGS
`FIG. 1 is an isometric view of the knitted fabric with the
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`central portion thereof broken away.
`FIG. 2 is an enlarged fragmentary plan view particularly
`illustrating the elastomeric yarn and poly cotton yarn strands
`of the sheeting material.
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
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`Referring now to the drawings, the knitted fabric 10 of the
`present invention is illustrated in FIGS. 1 & 2. Although the
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`6,164,092
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`present invention is directed toward the use of the knitted
`fabric 10 for bed sheets, and in particular contour fitted bed
`sheets designed specifically for institutions, it is recognized
`that the knitted fabric 10 may also be used to make flat
`sheets, fitted-fiat sheets, crib sheets, pillowcases, stretcher
`sheets, sheets for sale in the retail market, and for the
`manufacturing of other textiles.
`
`In general, the knitted fabric 10 of the preferred embodi-
`ment comprises a knitted material having a yarn strand 12,
`made of a blend of natural and synthetic fibers, and an
`elastomeric strand or hyper-elastic yarn 14. The yarn strand
`12 is knitted together with the elastomeric strand 14 as
`illustrated in FIG. 2 to created a single piece of textile or
`knitted fabric 10.
`
`The novelty of the knitted sheet 10 lies in the fiber content
`and combination of the two strands of yarn 12 and 14. As
`seen in FIG. 1, the yarn strand 12 and the elastomeric strand
`14 are knitted together to form a single jersey fabric which
`produces, in one embodiment, a finished sheet measuring
`approximately 34"><71“><14“ and weighing between 13 and
`30 ounces depending on the over all fabric blend of the
`elastomeric strand 14 and the yarn strand 12.
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`Typically, the yarn strand 12 contains approximately 40%
`natural fiber and 60% synthetic material to 60% natural fiber
`and 40% synthetic fiber. Although any suitable synthetic
`material may be used in the yarn strand 12, it is preferred
`that
`the synthetic material be polyester. Likewise,
`it
`is
`preferred that
`the natural material be a combed cotton,
`although any suitable natural material such as wool or silk
`may be used as the yarn strand 12. Thus, the yarn strand 12
`is comprised preferably a poly-cotton blend.
`
`The elastomeric strand 14 of the knitted material may be
`comprised of any elastic textile fiber, however, it is preferred
`that the material be made of the elastomeric textile fiber
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`known as spandex. Therefore, in the preferred embodiment,
`the knitted fabric 10 comprises a blend of poly-cotton yarn
`and spandex.
`
`As seen in FIG. 2, the fabric is knitted so that there is a
`1:1 ratio of elastomeric yarn 14 to poly-cotton yarn 12.
`While the ratio of elastomeric strands 14 to yarn strands 12
`is 1:1, the weight and percentage blend of the poly-cotton
`yarn to elastomeric yarn is not necessarily a 50/50 ratio. The
`blend of a finished sheet ranges from 99.9% poly-cotton and
`0.01% elastomeric material to 90% poly-cotton and 10%
`elastomeric material. Accordingly, depending upon the per-
`centage blend of elastomeric yarn 14,
`the weight of a
`finished 34"><71“><14“ sheet can range from 13 ounces to 30
`ounces. Because the fabric is knitted with a 1:1 ratio of
`
`elastomeric yarn to poly-cotton yarn, the variation between
`fabric weights and blends are made possible by varying the
`size of the yarn strand and the denier of the elastomeric
`strand.
`
`While the contents of the yarn strand 12 may range from
`approximately 40% natural fiber and 60% synthetic material
`to 60% natural fiber and 40% synthetic fiber, it is preferred
`that the yarn strand 12 be of a size 32/single and made of an
`intimate blend of 58% combed cotton and 42% polyester to
`60% combed cotton and 40% polyester. Preferably,
`the
`elastomeric yarn is a size 40 denier. This combination of the
`size 32/single yarn strand and 40 denier elastomeric material
`produces a 34"><71“><14“ finished sheet weighing approxi-
`mately 23.5 ounces that has an overall fabric blend of 55%
`cotton, 41% polyester, and 4% elastomeric material.
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`As discussed above, the weight and blend of the fabric can
`be easily altered by increasing or decreasing the denier size
`of the elastomeric strand, increasing or decreasing the size
`of the yarn strand or increasing or decreasing both the size
`of the elastomeric strand and the yarn strand. For example,
`one can increase the weight of the finished sheet and
`increase the percentage of elastomeric material in the overall
`fabric blend, by using a larger denier of elastomeric material.
`It is recommended that overall fabric blends comprise yarn
`sizes ranging between size 10/single and size 45/single of
`poly-cotton yarn and ranging between a size 10 denier and
`size 60 denier elastomeric yarn.
`To manufacture the knitted fabric 10 of the present
`invention, one may use a standard knitted fabric machine
`such as a Fukahara Model FXC-3S. To obtain a 1:1 ratio of
`poly-cotton yarn to elastomeric yarn, the machine is fitted
`with special feeders such as the Meminger-Iro feeders.
`These feeders pass the spandex or elastomeric yarn to the
`knitting bed of the knitting machine. These special feeders
`are then used in an alternating fashion so that the 1:1 ratio
`of elastomeric yarn to poly-cotton yarn is feed into the
`knitting needles.
`In a second embodiment of the present invention, the
`knitted fabric 10 is constructed the same as the knitted fabric
`10 of the preferred embodiment except the yarn strand 12 is
`made entirely of natural fibers, preferably combed cotton,
`but could also comprise silk, wool or other like substances.
`No synthetic fibers are used in the yarn strand 12. Therefore,
`the overall knitted fabric comprises a blend of combed
`cotton and elastomeric material.
`
`In yet a third embodiment of the present invention, the
`knitted fabric 10 is again constructed the same as the knitted
`fabric 10 of the preferred embodiment except that the yarn
`strand 12 is made entirely of synthetic fibers, preferably
`polyester. No natural fibers are used in the yarn strand 12 of
`this embodiment, and thus, the overall knitted fabric com-
`prises a blend of polyester elastomeric material.
`While a preferred embodiment of the present invention
`has been illustrated and described, it will be apparent that
`changes may be made in the general construction and
`arrangement of the invention without departing from the
`scope thereof. It is therefore desired that the scope of the
`invention not be limited to the exact disclosure, but defined
`by the appended claims.
`I claim:
`1. A fitted bedsheet formed from a knitted fabric com-
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`prising:
`a first yarn strand comprising poly-cotton fiber having a
`fiber content of at least 55% natural cotton material;
`a second yarn strand comprising Spandex; and
`said first and said second yarn strands being knitted
`together in an overall resulting fabric blend comprising
`a range of 90—99.9 weight percent (%) of said first yarn
`strand, and a range of 0.01—10% of said second yarn
`strand, and then sewn in the form of a fitted bedsheet.
`2. Abedsheet formed from a knitted fabric as set forth in
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`claim 1 wherein said at least first yarn strand comprises at
`least forty (40%) percent polyester.
`3. Abedsheet formed from a knitted fabric as set forth in
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`claim 1 wherein said at least first yarn strand contains a
`blend of approximately fifty-eight (58%) combed cotton and
`approximately forty-two (42%) percent polyester.
`4. Abedsheet formed from a knitted fabric as set forth in
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`claim 1 wherein said at least first yarn strand is in the range
`of size 10/single and 45/single.
`5. Abedsheet formed from a knitted fabric as set forth in
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`claim 4 wherein said at
`32/single.
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`least
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`first yarn strand is size
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`6,164,092
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`6. Aknitted fabric as set forth in claim 1 wherein said at
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`8. Aknitted fabric as set forth in claim 1 wherein said at
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`least second yarn strand is in the range of size 10 denier and
`60 denier.
`7. Aknitted fabric as set forth in claim 1 wherein said at
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`least first yarn strand and said at least second yarn strand are
`knitted together in a 1:1 ratio.
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`least second yarn strand is size 40 denier.
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