Note: Descriptions are shown in the official language in which they were submitted.
CA 02509760 2005-06-13
CIRCULAR-KNIT BED SHEET
Background of the Invention
Field of the Invention
[0001] This invention is directed to bed sheets and the like, and more
particularly, to circular-knit bed sheets and the like.
Description of Related Art
[0002] Since the early 1990s, the U.S. healthcare marketplace has made
a decided and easily-discernible shift from woven to knitted contour or
"fitted"
sheets and, to a lesser extent, knitted pillow cases, flat sheets, draw
sheets, and
the like. These knitted products are perceived to be of greater utility
because of
the wider range of bed, mattress, and pillow sizes for which such products may
be
utilized.
(0003] Most commonly, these knit fabrics are made with a blend of cotton
yarns and/or cotton/polyester yarns, although some 100% cotton versions are
1
CA 02509760 2005-06-13
available in the marketplace. One product is known to exist which incorporates
4%o spandex elastomeric yarn, in combination with cotton/polyester spun yarns.
(See Menaker U.S. Patent No. 6,164,092.)
[0004] As usage of these products has increased, several issues
concerning product durability have been identified. Specifically, these
include the
high propensity of circular-knit fabrics to develop "pinholes" caused by
breaks in
the knitted chain structure, and to undergo "chaining" where the sheet, in
essence, tears apart along a broken thread line. Also, such products tend to
have
relatively poor dimensional stability as compared with woven fabrics. These
issues further include a recognition that suitable commercial durability is
only
reasonably achieved by increasing overall fabric weight to a level much higher
than that of traditional woven goods. However, such an increase in fabric
weight
increases acquisition- and processing- expenses.
Summary of the Invention
[0005] The present invention provides circular-knit bedding, such as bed
sheets and the like, having a greater durability than products made with
conventional circular-knit fabrics, without an overall increase in fabric
weight and
the corresponding acquisition- and processing- costs, and without sacrificing
the
comfortable feel of the bedding. To this end, and in accordance with the
principles of the invention, the durability enhancement is accomplished by non-
pile circular-knitting at least one spun yarn and at least one synthetic
filament
yarn, the synthetic filament yarn being without loose filament-ends sticking
out
along its length, and further having an elongation-at-break of not more than
50%.
2~
CA 02509760 2005-06-13
A bed sheet, or other bedding product, may be made by converting a length of
r.
the resulting non-pile circular-knit fabric into the desired product.
[0006] By virtue of the foregoing, there is thus provided a circular-knit
fabric and bedding which provide enhanced durability while maintaining a
comfortable feel, and without increasing overall fabric weight. These and
other
advantages of the present invention will be apparent from the accompanying
drawings and description of the drawings.
Brief Description of the Drawings
[0007] The accompanying drawings, which are incorporated in, and
constitute a part of this specification, illustrate embodiments of the
invention, and,
together with the general description of the invention given above, and the
detailed description of the drawings given below, serve to explain the
principles of
the invention. The drawings are schematic, and are not to scale.
[0008] Fig. 1 is a perspective view of a tube of non-pile circular-knit fabric
in accordance with the principles of the invention;
[0009] Fig. lA is an enlarged fragmentary elevational view of a portion of
the fabric of Fig. 1;
[0010] Fig. 2 is a perspective view of the fabric of Fig. 1, with the tube
having been slit open;
[0011] Fig. 3 is a perspective view of a roll of the non-pile, circular-knit
fabric of Fig. 2; and
[0012] Fig. 4 is a perspective view of a fitted sheet made from a length of
fabric taken from the roll of Fig. 3, in accordance with the principles of the
3
CA 02509760 2005-06-13
invention. For purposes of illustration, the fitted sheet is oriented as if it
were
positioned in place on a mattress (not shown).
Detailed Description of the Drawings
[0013] With reference to Figs. 1 and lA, a tube 10 of non-pile circular-
knit fabric 12 is circular-knit in a conventional fashion with a plurality of
series of
loops of yarn, with at Least one yarn being a spun yarn 14 and at least
another
yarn being a synthetic filament yarn 16. The synthetic filament yarn 16 has an
elongation-at-break of not more than about 50%, and does not have loose
filament-ends sticking out along its length. The resulting non-pile circular-
knit
fabric 12 has a plurality of courses, as at 18, running across the fabric
(i.e.,
transverse to the longitudinal axis 20 thereof), and a plurality of Wales, as
at 22,
running the length of the fabric 12 (i.e., parallel to axis 20). The tube 10
may be
slit open by making a cut in the endless circumferential sidewall 24 of the
tube
10, with the cut running the length of the tube 10 and being parallel to the
longitudinal axis 20 thereof, as at the line 26. Once the cut is made, the
fabric 12
may be laid open as indicated by the arrows 28a, b into an elongated sheeting
as
seen in Fig. 2. The opened fabric 12 has a first lengthwise edge 30 and a
second
lengthwise edge 32, both having been created by the longitudinal cut 26.
[0014] With reference to Figs. 2 and 3, the opened fabric 12 then may be
rolled up in a direction parallel to axis 20, thereby forming a roll 34 of the
fabric
12 for use in subsequent processing steps. The first and second lengthwise
edges
30, 32 of the opened fabric 12 also are visible on the rolled-up fabric 12.
4.
CA 02509760 2005-06-13
[0015] As will be appreciated, the spun yarn 14 may be made of any
suitable material or combination of materials. For example, the spun yarn 14
may be 100% cotton or a combination of cotton and other material(s). If all-
cotton yarn is used, such yarn advantageously may have a yarn count in the
range of about 20 singles to about 30 singles. The synthetic filament yarn 16
may be made of any suitable material or combination of materials. For example,
polyester or other acceptable polymers may be used. In addition, the filament
yarn 16 may have any suitable denier. For example, the yarn 16 may have a
denier in the range of about 50 to about 300, or about 75 to about 150. Also,
the yarn 16 may be a singles yarn, a plied yarn, or other suitable yarn type.
If
desired, the yarn 16 may be a 150 denier, 48 filament, polyester yarn. The
spun
yam 14 and synthetic filament yam 16 may have any other suitable
characteristics, as desired, including for example, any suitable spun-yarn
count or
counts.
[0016] The non-pile circular-knit fabric 12 may have any suitable ratio or
ratios of spun yarn 14 to synthetic filament yarn 16. For example, if the spun
yarn 14 is a 100% cotton yarn, the spun yarn 14 may represent about 55% to
about 60% by weight, and the synthetic filament yarn 16 may represent from
about 40% to about 45% by weight. Also, if desired, the fabric 12 may have a
fabric weight of about 100 to about 250 grams per square meter (g/m2).
[0017] With reference to Fig. 4, a fitted bed sheet 36 made from a length
of fabric taken from the fabric roll 34 (Fig. 3) has a first lengthwise edge
38
corresponding with the first lengthwise edge 30 of the fabric 12, and a second
5
CA 02509760 2005-06-13
lengthwise edge 40 corresponding with the second lengthwise edge 32 of the
fabric 12. The sheet 36 further includes a first sidewall 42 adjacent the
first edge
38, a second sidewall 44 adjacent the second edge 40, a head wall 46, an end
wall 48, and a top wall 50 extending therebetween. In addition, the sheet has
an
edge 52 adjacent the head wall 46, an edge 54 adjacent the end wall 48, a seam
55a, b, c, d at each corner of the sheet 36, and a binding strip 56 sewn to
the
sheet 36 adjacent the edges 38, 40, 52, and 54.
[0018] The sheet 36 may be made from the fabric 12 using customary
methods and equipment, including, for example, any desired finishing
treatment(s), cutting, and sewing. Examples of finishing treatments include
the
application of an antimicrobial finish, a flame-retardant finish, a no-iron
finish, a
no-stain finish, an optical brightener, and/or a color. As would be
appreciated by
one of ordinary skill, such finishing treatments may be applied to the yarns
used
to form a non-pile circular-knitted fabric, to a non-pile circular-knitted
fabric in its
greige state, and/or to the sheets or other bedding items which are made from
the
fabric. As also would be appreciated, one or more of the converting- or
finishing-
aspects may include cutting and removing a piece of fabric from each corner of
a
to-be-completed fitted sheet, and seaming the remaining corner fabric to form
the
various walls and edges of the sheet. Another aspect may include sewing of a
binding strip to one or more of the edges. For example, a binding strip (not
shown) may be sewn to each of the first and second elongated edges 30, 32 of
the fabric 12 shown in Fig. 2. Alternatively, such binding strips may be sewn
to
elongated lengthwise edges of a length of fabric (not shown) cut from the roll
34
6
CA 02509760 2005-06-13
of fabric 12 shown in Fig. 3. In addition, as will be appreciated by one of
ordinary skill, a binding strip or strips may be sewn to any of the exposed
edges
of a length of fabric during the formation of the fitted sheet 36 (Fig. 4) or
any
other bedding product made from the non-pile circular-knit fabric 12.
[0019] In use, a non-pile, circular-knit fabric may be formed, in which the
fabric includes at least one spun yarn and at least one synthetic filament
yarn,
with the synthetic filament yarn having an elongation-at-break of not more
than
about 50% and being without loose filament-ends sticking out along its length.
Individual sheets and other bedding products then may be made from the fabric.
[0020] The non-pile circular-knit greige fabric, the partially-converted or
partially-finished fabric, and the bed sheets and other bed-sheeting products
described above provide several benefits and advantages. For example, the non-
pile circular-knit bedding has a durability greater than that of products made
with
conventional circular-knit fabrics, without an overall increase in fabric
weight and
the corresponding acquisition- and processing- costs. Furthermore, this
enhanced durability is achieved without sacrificing the comfortable feel of
the
bedding.
[0021] By virtue of the foregoing, there is a non-pile circular-knit fabric,
as
well as bedding products made from the fabric, both of which have advantages
over prior circular-knit fabrics and bedding made from those fabrics.
[0022] While the present invention has been illustrated by a description of
embodiments, and while the illustrative embodiments have been described in
considerable detail, it is not the intention of the inventor to restrict or in
any way
7
CA 02509760 2005-06-13
limit the scope of the appended claims to such detail. Additional advantages
and
modifications readily will appear to those skilled in the art. For example,
any
given fabric of the invention may include a plurality of spun yarns and/or a
plurality of synthetic filament yarns. Furthermore, one or more of the
plurality of
spun yarns may have a characteristic or characteristics different from that of
another of the spun yarns. Likewise, one or more of the plurality of synthetic
filament yarns may have a characteristic or characteristics different from
that of
another of the synthetic filament yarns. Also, although one of the drawings
illustrates a fitted bed sheet, the fabrics of the invention may be used to
form flat
sheets, blankets, towels, pillow cases, and other sized-specific flat-goods.
The
invention in its broader aspects is therefore not limited to the specific
details,
representative apparatus and methods, and illustrative examples shown and
described. Accordingly, departures may be made from such details without
departing from the spirit or scope of the inventor's general inventive
concept.
[0023] What is claimed is:
8
