U.S. patent application number 12/571819 was filed with the patent office on 2010-04-15 for elastic fabrics and methods and apparatus for making the same.
Invention is credited to Nalantha De Alwis, Robert Arthur Glenn, Krishan Weerawansa.
Application Number | 20100093258 12/571819 |
Document ID | / |
Family ID | 42099291 |
Filed Date | 2010-04-15 |
United States Patent
Application |
20100093258 |
Kind Code |
A1 |
Glenn; Robert Arthur ; et
al. |
April 15, 2010 |
Elastic Fabrics And Methods And Apparatus For Making The Same
Abstract
The invention relates to methods and apparatus for making a
length of woven fabric comprising an elastomeric weft yarn. The
lengths of fabric obtained are particularly useful as shoulder
straps for garments such as bras. Preferred embodiments relate to
tapered fabric which is useful as a component of articles of
clothing, especially a bra wing.
Inventors: |
Glenn; Robert Arthur;
(Loughborough, GB) ; Weerawansa; Krishan;
(Walgama, LK) ; De Alwis; Nalantha; (Panadura,
LK) |
Correspondence
Address: |
MORGAN LEWIS & BOCKIUS LLP
1111 PENNSYLVANIA AVENUE NW
WASHINGTON
DC
20004
US
|
Family ID: |
42099291 |
Appl. No.: |
12/571819 |
Filed: |
October 1, 2009 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61136927 |
Oct 15, 2008 |
|
|
|
Current U.S.
Class: |
450/86 ; 139/11;
139/387R; 139/421; 2/243.1; 450/92 |
Current CPC
Class: |
D03D 17/00 20130101;
D03D 15/56 20210101; D03D 3/06 20130101; D03D 1/00 20130101; D10B
2501/02 20130101; D10B 2401/061 20130101; A41F 15/00 20130101; D03D
3/02 20130101 |
Class at
Publication: |
450/86 ; 139/421;
139/11; 139/387.R; 2/243.1; 450/92 |
International
Class: |
A41F 15/00 20060101
A41F015/00; D03D 15/08 20060101 D03D015/08; D03D 41/00 20060101
D03D041/00; D03D 3/02 20060101 D03D003/02; A41C 3/00 20060101
A41C003/00 |
Claims
1. A method of making a length of woven fabric having a variable
width, the method comprising weaving warp yarn with weft yarn; and
characterised in that the weft yarn is elastomeric and is arranged
across the warp yarn to vary the width of the woven fabric along
its length.
2. A method as claimed in claim 1 wherein the elastomeric weft yarn
is arranged by varying the weft yarn feeding speed.
3. A method as claimed in claim 1 wherein the warp yarn consists of
or comprises an elastomeric yarn.
4. A method of making a fabric as claimed in claim 1 wherein the
elastomeric weft yarn is arranged to produce a tapered fabric.
5. A method as claimed in claim 4 wherein the elastomeric weft yarn
is arranged to produce a tapered fabric by increasing or decreasing
the weft yarn feeding speed incrementally.
6. A method as claimed in claim 4 wherein the tapered fabric has
outer edge portions flanking an inner body panel; and wherein the
outer edge portions have different elastic modulus properties as
compared to the elastic modulus properties of the inner body
panel.
7. A method of making a length of woven fabric comprising weaving
warp yarn and elastomeric weft yarn; wherein either the pick
density, the warp density, or both the pick density and warp
density is varied during weaving to produce two or more portions
along either the length, the width, or both the length and width of
the woven fabric having different elastic modulus properties.
8. A method of making a length of woven fabric comprising weaving
elastomeric warp yarn with elastomeric weft yarn under tension,
whereby the width of the woven fabric increases compared to its
width in a relaxed state upon applying a longitudinal load to the
fabric.
9. A method as claimed in claim 1 further comprising a step of
incorporating the length of fabric into a textile article.
10. A method as claimed in claim 9 wherein the textile article is
an article of clothing.
11. A method as claimed in claim 9 wherein the fabric is
incorporated as all or part of a shoulder strap or waistband.
12. A method as claimed in claim 9 wherein the article of clothing
is a bra.
13. A method as claimed in claim 1 wherein the length of fabric is
incorporated into a non-textile article as all or part of a
shoulder strap.
14. A length of woven elastic fabric obtainable by a method as
claimed in claim 1 the fabric having along its length two or more
portions of different width.
15. A length of woven fabric having two or more portions of
different width along its length; wherein the fabric comprises
elastomeric weft yarn arranged across warp yarn.
16. A length of woven fabric as claimed in claim 14 wherein the
fabric is tapered.
17. A length of woven fabric as claimed in claim 14 wherein the
warp yarn consists of or comprises an elastomeric yarn.
18. A length of woven fabric comprising warp yarn and elastomeric
weft yarn; characterised in that the elastomeric weft yarn is
arranged whereby the width of the fabric can be increased compared
to its width in a relaxed state by applying a longitudinal load to
the fabric.
19. A length of woven fabric comprising elastomeric weft yarn
arranged across warp yarn; wherein either the pick density, the
warp density, or both the pick density and the warp density varies
along either the length, the width, or both the length and width of
the woven fabric to produce two or more portions having different
elastic modulus properties.
20. A tubular fabric formed from a length of woven fabric as
defined in claim 14.
21. A textile article incorporating a length of fabric as claimed
in claim 14.
22. A textile article as claimed in claim 21 wherein the article is
an article of clothing.
23. An article as claimed in claim 22 selected from sportswear and
undergarments.
24. An article as claimed in claim 21 wherein the length of fabric
is incorporated as all or part of a shoulder strap.
25. An article as claimed in claim 22 wherein the length of fabric
is incorporated as all or part of a waist band.
26. A non-textile article which incorporates a length of fabric as
claimed in claim 14 as all or part of a shoulder strap.
27. (canceled)
Description
[0001] The present invention relates to elastic fabrics and methods
of making the same. The fabrics are particularly suitable for
incorporating into textile goods, particularly clothing garments,
and especially brassieres and other garments which include a
shoulder strap. The fabric of the invention can also be
incorporated into other goods with straps, such as bags, carrying
cases, etc.
[0002] It is known to make elastic shoulder straps having variable
width along their length. Because of their elasticity, the shoulder
straps can follow the movements of the body or the body parts of
the wearer, so that the article of clothing supported by the
shoulder strap exerts no tensile or compressive stresses or only
slight tensile or compressive stresses onto the body of the wearer
of the article of clothing. A shoulder strap of this type is placed
over the shoulder of the wearer, wherein the longitudinal middle
portion of the shoulder strap rests on the shoulder and the two
shoulder strap portions connected to the middle portion extend
downwardly along the chest and back, respectively, of the wearer
and are connected at their ends to the article of clothing
[0003] U.S. Pat. No. 5,507,682 describes a shoulder strap that
includes elastic warp threads and weft threads extending
transversely of and woven into the elastic warp threads.
[0004] The strap has a longitudinal middle portion whose width is
enlarged as compared to the width of the shoulder strap portions
extending longitudinally from the middle portion. The spacing
between the elastic warp threads in the middle portion is greater
than the spacing of the elastic warp threads in the shoulder strap
portions connected to the middle portion. The number of weft
threads per unit of length in the longitudinal middle portion is
greater than in the shoulder strap portions connected to the middle
portion. The number of weft threads per unit of length in the
middle portion may be approximately 50% greater than the number of
weft threads per unit of length in the shoulder strap portions
connected to the middle portion.
[0005] The present invention aims to provide a simple, quick and
economical method and apparatus for making an elastic fabric of
variable width.
[0006] According to the invention there is provided a method of
making a length of woven fabric having a variable width, the method
comprising weaving warp yarn with weft yarn; characterised in that
the weft yarn is are elastomeric and the elastomeric weft yarn is
arranged across the warp yarn to vary the width of the woven fabric
along its length.
[0007] Conveniently, the method involves varying the tension under
which the elastomeric weft yarn is laid across the warp yarn by
varying the weft yarn feeding speed. Increasing the weft yarn
feeding speed lowers the tension on the weft yarn and the width of
the woven fabric increases. Lowering the weft yarn feeding speed
increases the tension and the width of the woven fabric
decreases.
[0008] Hence, simply by controlling the elastomeric weft yarn
feeding speed one can control the width of the resulting woven
fabric according to the method of the invention.
[0009] Alternatively, or additionally, the tension under which the
weft yarn is laid across the warp yarn can be varied by varying the
weaving pattern. For example, weaving a weft thread under every
other warp thread will produce a tighter weave than weaving the
weft thread under two or more warp threads at a time.
[0010] Normally, a non-elastomeric yarn is used for the weft yarn
in known methods of making shoulder straps. However, in a preferred
embodiment of the present invention both the warp yarn and weft
yarn are elastomeric. This produces a woven fabric that can be
stretched along its length (i.e. warp-ways) and across its width
(i.e. weft-ways). Stretchiness in both directions leads to greater
comfort for a user when the length of a fabric is used as a
shoulder strap as it makes the strap move with the shoulder muscles
rather than causing abrasion by rubbing against the skin.
[0011] A particularly unexpected and advantageous property of
fabric woven according to the present invention is that when the
fabric is stretched close to its maximum extent, its width
increases compared to its width in a relaxed state. This is
particularly beneficial when the fabric is used as a shoulder strap
because increasing the width spreads the load over a bigger area.
This reduces the pressure that a wearer will feel on their
shoulder, making it much more comfortable than conventional
shoulder straps.
[0012] In a further aspect the invention provides a method of
making a length of woven fabric, the method comprising weaving warp
yarn with elastomeric weft yarn; characterised in that the
elastomeric weft yarn is laid across the warp yarn under tension
whereby the width of the woven fabric increases compared to its
width in a relaxed state upon applying a longitudinal load to the
fabric.
[0013] The invention also relates to a woven length of fabric
characterised in that the fabric comprises warp yarns and
elastomeric weft yarns arranged whereby the width of the fabric can
be increased compared to its width in a relaxed state by applying a
longitudinal load to the fabric.
[0014] Preferably, both the weft and warp yarns consist of or
comprise elastomeric yarn.
[0015] Another advantage of the method of the invention is that the
spacing between threads of the weft yarn is substantially the same
throughout the length of the fabric. Hence the stretch and modulus
properties will not vary significantly between portions of the
fabric having different widths.
[0016] In a preferred embodiment the method involves arranging the
elastomeric weft yarn across the warp yarn so as to produce a
tapered fabric. By "tapered" we mean that the width of the fabric
decreases incrementally.
[0017] Conveniently, such an arrangement is achieved by varying
(i.e. increasing or decreasing) incrementally the tension under
which the elastomeric weft yarn is fed across the warp yarn.
[0018] According to this embodiment the method can be used to
produce tapered elastic fabric panels which are useful as
components of a bra, especially wing (side) panels. Normally, a
wing panel fora bra is made from several separate components, the
elastic fabric being stitched to the edges of the panel. However,
such a multi-component construction has the disadvantage that it is
complicated to assemble, bulky and sometimes uncomfortable for the
wearer, especially on bras with larger cup sizes.
[0019] Bra wing panels made according to the method of the
invention offer better levels of elastic support than known
multicomponent panels, but they are far easier to make and more
comfortable to wear because they can be made as a monocomponent
seam-free fabric.
[0020] Improved support over conventional bra wing panels can
result from the use of elastomeric warp and weft yarns. The
resulting woven fabric can stretch across its width in addition to
the normal stretch along its length.
[0021] In a still further aspect the invention provides a method
for making a length of woven elastic fabric comprising weaving warp
yarn and elastomeric weft yarn; wherein the pick density and/or
weave pattern is varied during weaving to produce two or more
portions along the length and/or width of the woven fabric having
different elastic modulus/stretch properties.
[0022] The warp density can be used to vary the elastic
modulus/stretch properties across the width of the woven fabric,
for instance, as described in the following examples.
[0023] Preferably the warp yarns comprise or consist of elastomeric
yarn.
[0024] Preferably, the pick density is varied by varying the speed
of the take-off roller of a weaving machine.
[0025] Conventional weaving machines are arranged to feed weft
yarns at a constant speed.
[0026] Thus, according to a further aspect the invention provides a
weaving machine wherein the machine is equipped with a controller
for feeding weft yarn at two or more different speeds.
[0027] Preferably, the weaving machine is equipped with a sensor
for detecting a predetermined length of fabric. Once a
predetermined length has been detected the sensor can signal the
controller to vary the speed at which the weft yarn is fed and
thereby vary the width of the resulting woven fabric. Conveniently
the controller is arranged to operate a motor, the motor being
connected to the weft feed wheel of the weaving machine.
[0028] It will be appreciated that the preferred weaving machine of
the invention can be programmed or otherwise set to produce a
length of woven fabric with a desired variable width pattern.
[0029] The invention also provides a weaving machine having a
take-off roller and having means to vary the speed of the take-off
roller to vary the pick density during a weaving operation.
[0030] Alternatively or additionally, warp yarns of a
higher/heavier count than those used in another portion of the
fabric can be used to achieve two or more portions having different
elastic modulus properties.
[0031] In the illustrative example below, more warp ends per dent
are used on the outer edge portions than in the centre body panel.
This is seen most clearly from the drawing-in plan where the
underband and underarm portions have 10 ends, whereas the centre
body panel only has 2 ends per dent (see FIGS. 9A and 9B).
[0032] In an embodiment, the invention provides a tubular fabric
formed from a length of woven fabric of the invention, such as a
flat or open form of the fabric of the invention. Methods for
manufacturing a tubular fabric from a flat or open form of a fabric
are known in the art. For example, the OB1 AT116 system produced by
Sew Systems Ltd., 53 Iliffe Avenue, Odeby, Leicester, LE5 5LH,
England, provides a convenient automated method whereby flat fabric
is passed through a folder system which takes the single flat strip
and forms it into a tubular form which can be sewn into a
garment.
[0033] Tubular fabrics are known to be of use in housing underwires
(such as brassiere wires) in underwired garments such as brassieres
or swimming costumes. Thus, the tubular fabric of the invention may
conveniently be used to house an underwire in an underwired garment
(such as brassiere or swimming costume), for example where a
tubular fabric having the advantageous properties of the fabric of
the invention are desired.
[0034] In a preferred embodiment, an anti-slip material is applied
to wide sections of the length of fabric after weaving. For
example, a silicone monolayer or two layers of silicone where the
first layer is silicone (against the fabric surface) and has a
higher viscosity than a second silicone layer on top of the first
layer. The low viscosity silicone has a much tackier (anti-slip)
surface. Silicone with low viscosity has a very tacky nature but it
bonds very weakly with textiles. Hence, by putting it over a higher
viscosity silicone that bonds well with textiles, the lower
viscosity silicone layer bonds well with the higher viscosity
silicone which in turn bonds well with the surface of the fabric to
create a durable layer of tacky silicone on the surface of the
fabric.
[0035] The use of such anti-slip material helps to prevent the
increased width section from slipping off the shoulder of a wearer
when the length of fabric is used as a shoulder strap.
[0036] Instead of, or as well as, applying an anti-slip coating
after weaving the product a tacky material like natural rubber may
be used in the warp yarn.
[0037] It is preferred that the above methods and apparatus are
used in combination with one or more of the other aspects of the
invention.
[0038] Details of exemplary preferred embodiments of the above
methods and apparatus of the invention are provided in the
following Examples and Figures.
BRIEF DESCRIPTION OF FIGURES
[0039] FIG. 1(i) is a schematic showing the arrangement of a
weaving machine for use in the methods of the invention.
[0040] FIG. 1(ii) is a schematic representation of a woven fabric
of the invention showing the warp and weft yarn arrangement and
illustrating how the width of the fabric can be controlled by
varying the feed speed of the weft yarn during the weaving
process.
[0041] FIG. 1(iii): photograph of actual length of fabric having
variable width.
[0042] FIG. 2A: shows exemplary lengths of fabric having different
variable width Designs.
[0043] FIG. 2B: photograph of actual fabric having variable width
designs shown in FIG. 2A.
[0044] FIG. 2C: corresponding weft yarn feed speeds used to achieve
the width variations A to D shown in FIGS. 2(A) and 2(B).
[0045] FIG. 3(a)(a-1)(a-2): exemplary weaving plan and a preferred
fabric construction according to the invention.
[0046] FIGS. 4A and 4B: schematic showing how the width of a
preferred fabric of the invention increases (FIG. 4B) as compared
to its width in a relaxed state (FIG. 4A) when a longitudinal load
is applied to the fabric.
[0047] FIG. 4C: drawings in plan and construction of the fabric
shown in FIGS. 4A and 4B.
[0048] FIG. 4D: photographs showing width extensions of actual
fabric.
[0049] FIG. 5: schematic showing arrangement of warp and weft yarns
to achieve portions along the length of the fabric having different
elastic modulus/stretch properties.
[0050] FIG. 6: shows variation in speed of take-off roller used to
achieve variations in stretch properties seen in FIG. 5.
[0051] FIG. 7: photograph of tapered fabric of the invention in the
form of a bra wing. Outer edge portions ("power bands") have a
different stretch property than the inner body panel. However the
entire bra wing is made as a single fabric using the weaving
methods of the invention.
[0052] FIG. 8: photograph of a conventional bra wing construction.
Elastic strips are stitched or bonded to a non-elastic fabric panel
which is cut to achieve a tapered shape. The attachment of the
elastic strips forms seams which adversely affects comfort for a
wearer.
[0053] FIG. 9A: shows weave construction of the preferred fabric of
the invention for use as a bra wing shown in FIG. 7. The underarm
and under-band outer edge portions have a high warp density.
[0054] FIG. 9B: shows the drawing-in plan and weave construction of
the inner body panel of the fabric shown in FIG. 7.
EXAMPLES
Example 1
Variable Width Fabric
[0055] The width of various types of narrow elastic and non elastic
tapes can be altered along the length at predefined positions using
a standard narrow fabric weaving or jacquard weaving loom. The
resultant product can be used for many applications and few options
are as follows. [0056] 1. Shoulder straps of ladies undergarments
(bra's or camisoles) as the wide area can be positioned over the
shoulder to reduce the pressure thus make the garment comfortable.
[0057] 2. Waist bands of apparel as the wider area positioned to
the front will help to control the stomach better. If the wider
area is positioned to the side it will help to suite the natural
curves of the body, especially on women. [0058] 3. Shoulder straps
for cameras, Camcorders or any equipment that is required carry
over the shoulder. [0059] 4. Straps of Bags. [0060] 5. Decorative
straps [0061] 6. Bra wings [0062] 7. Tubular fabrics, such as
fabrics for housing an underwire in an underwired garment (such as
a brassiere or swimming costume).
[0063] Normally the width of a narrow tape is entirely dependent on
the width of the front read and the feed/tension of the weft yarn.
Both these parameters are constant once set, hence products woven
using these machines end up having a consistent width through out
its length.
[0064] In order to achieve various widths at different places along
the length of the elastic fabric according to the invention it is
preferred that the feed/speed of the weft yarn is varied at
pre-defined places whilst the weaving machine is in continuous
operation, without interrupting the rest of its functions.
[0065] Preferred elastomeric yarn for use in the methods of the
invention includes "spandex" or "elastane" which is a block
copolymer of polyurethane and polyethylene glycol. Trademarks
associated with spandex products include Lycra.TM., Elaspam.TM.,
ROICA.TM., Darlaston.TM. and Linel.TM..
[0066] Spandex is produced as monofilament or fused multifilament
yarns in a variety of deniers, as is well known in the art.
[0067] Upon application of a tensile load at room temperature,
elastomeric yarn such as spandex can be stretched without breaking
to more than twice its normal length in a relaxed state. When the
tensile load is released the elastomeric yarn immediately returns
to its original (relaxed) length.
[0068] Spandex (Elastane.TM.) or another elastomeric yarn can be
used in it's bare form or covered ones (single covered) or twice
(double covered) or even air covered with another textile yarn
(Nylon, Polyester, Rayon . . . etc). The advantage in using an
elastomeric yarn is that even when the feed speed is reduced to a
great extent, it only gets stretched out and does not break.
Further, it also gets woven into the product under tension in its
stretched out form and contracts the product once the woven fabric
passes the front reed of the weaving machine. It is important to
note that when an elastomeric yarn such as spandex is used as the
weft yarn a width reduction of upto 50% can be achieved compared to
15% that can be achieved when using a non-elastomeric textile
yarn.
Procedure
[0069] Control of the speed at which the weft yarn is fed is
accomplished by means of a sensor, a micro controller and an
electric motor that are all interconnected (see FIG. 1(i)).
[0070] Sensor: The prime function of the sensor is to identify each
revolution of the Main Shaft while the machine is in operations.
Each revolution of the Main shaft is equivalent to a pick. This
information is fed in to the microcontroller so that it can keep a
count on picks of the repeat while the machine is in operation.
[0071] Electric Motor: Drives the weft transport units and varies
its speed based on the instruction that it receives from the Micro
Controller. The weft transport unit is normally driven through a
series of pulleys and belts connected to the main or the crank
shaft. This drive is dismantled when fixing the electric motor
because in this new set-up the motor is connected directly to the
weft transport unit through a belt making it operate independently
of the main motor of the weaving machine.
[0072] A Micro Controller: A programmable device which controls the
speed of the motor that is fixed to the weft transport unit. The
inputs to the Micro controller are signals from the sensor which
help it to count the picks while the woven machine is in operation
and the Data inputs. The data input is the instruction that we feed
which advice the motor to change its speed from R1 to R2 from pick
P1 to P2. Speed values (R1, R2, R3 . . . Rx) are set based on the
desired width at different points and the shape in which the width
should be varied is set by the number of picks (P1, P2, P3 . . .
Px) over which the speed change is done. (See FIG. 2)
Width Increase when Fabric is Stretched
[0073] Another feature of the invention is that when the fabric is
stretched to its maximum extent, it increases its width by about
10-15% compared to its width in a relaxed state. This is
advantageous because the increased width spreads the load over a
larger area. Hence the pressure that a wearer feels will be less on
the shoulder and thus will be more comfortable.
[0074] As shown in FIGS. 4A and 4B, when the elastomeric weft yarn
(e.g. Spandex/Elastane) is fed in under tension (at a low rate) it
gets woven in stretched out and when the length of woven fabric
comes out of the take off rollers it contracts across its width.
This contraction causes the down points of the face warp yarns
(which works on a 7 up 1 down weave and up points of the back yarns
that works on a 7 down 1 up weave) to move underneath 7 up floats
and 7 down floats respectively. Since the elastomeric warp yarns
are stretched out on the loom lengthwise, when it retracts back
(lengthwise) once it comes out of the take off rollers, all the
non-elastic yarns specially the 7 down and 7 up floats jut out of
the surface creating a space underneath it. This makes it easier
for the single up and single down points of the warp to move
underneath those floats.
[0075] When the elastic is stretched to its maximum extent, once
the non-elastomeric warp yarns get stretched overcoming the crimp,
the single up points and single down points move out from
underneath the long warp floats and orient parallel to each other,
resulting in an increase of width by about 10%-15%.
[0076] The given construction is only an example and similar
products can be made using various different configurations using
the above principle.
Example 2
Variable Stretch/Modulus Elastic
[0077] The stretch of woven elastic fabric is primarily dependent
on the stretch of the elastomeric yarn, rate at which the
elastomeric yarn is fed, weave construction; warp density and the
pick density (picks per centimetre). However for a given product
all the parameters except the weave construction are uniform
throughout the weaving process. Hence the resultant elastic fabric
ends up with uniform stretch and modulus right along its length. By
using a jacquard machine, one can change the weave construction to
different areas to give different stretch and modulus properties.
When the construction is with a tight weave the stretch becomes low
and when the construction is loose the stretch becomes high and the
modulus becomes low. For example at one part the non elastic warp
yarns work on a 1 up 1 down weave working opposite to the
elastomeric/rubber yarns which also work on a 1 up 1 down weave one
will end up with a very low stretch and high modulus) compared to a
2 in 2 or 3 in 3 weave construction. However with this method it is
not possible to achieve specific stretch values because not only
the stretch gain or loss is limited the weave combinations that can
be used are limited too.
[0078] Control of pick density at portions along the length of the
fabric is achieved by controlling the speed of the take-off roller
without interrupting the other operations of the machine during the
weaving process. The pick density of a fabric product is primarily
dependent on the surface speed of the take-off rollers.
Machine picks per centimetre = Picks per minute Surface speed of
the take off roller ##EQU00001## Picks per minute = RPM of the main
Shaft Surface speed of the take roller = Circumference of the take
off roller .times. RPM of the take off roller . ##EQU00001.2##
[0079] As mentioned above, with conventional narrow fabric woven or
Jacquard weaving looms, the machine picks per centimetre is uniform
throughout the weaving process because the take-off roller is
worked by a series of gear wheels driven from the main shaft where
the gear ratio is fixed once set. The speed of the main shaft is
consistent throughout the process of weaving.
[0080] The machine for varying the stretch and modulus along the
length of the fabric is like that used to make fabric of variable
width according to Example 1. However, the machine is equipped with
means (an additional electric motor) to vary the speed of the
take-off roller while the weaving process is in operation without
interrupting any other operations. In order to do the above
modification the transmission from the main shaft to the take-off
roller has to be dismantled. The additional electric motor is also
connected to the microcontroller and it can instruct the two motors
independently to work at different speeds over different pick
intervals.
[0081] The nature of any elastic fabric is such that, if all the
other variables are kept consistent and only the pick density is
reduced the product will end up with a higher stretch compared to
the original product, similarly if the pick density is increased
the resultant elastic will end up with a lower stretch. Since the
speed of the take-off roller is varied which in turn changes the
pick density, an elastic fabric with portions along its length
having different stretch properties can be produced according to
the invention.
Example 3
Bra Wing
[0082] Using the variable width methods of the invention an elastic
fabric can be made to the tapered shape of a bra wing (as shown in
FIG. 7). Since an elastomeric yarn is used for the weft, the
resultant fabric has a stretch both lengthwise as well as
widthwise. By using very fine single covered elastomeric yarn, e.g.
spandex, along the length, a quite thin fabric can be woven which
is very similar to a conventional bra wing panel fabric in terms of
the hand feel and the drape. Further, it is also possible to
achieve the features ("power bands") that a regular cut and sew or
bonded bra wing has where an elastic is stitched or bonded to the
edge of the tapered fabric panel, by either increasing the warp
density at the edges or by using a thicker elastomeric yarn at the
edge of the tapered elastic fabric. This eliminates the irritating
stitching as well as the bulky seams of conventional bra wings and
thereby increases the user comfort for a wearer.
[0083] However, since this method of making a fabric can create a
very strong modulus along the length, even without having power
bands like explained above, this product is suitable to use as a
bra wing.
[0084] Further by incorporating the variable modulus aspects of the
invention and/or by using different weave constructions it is
possible to create different portions with different elastic
modulus/stretch properties ("power zones"). Such features also help
to create a better fitting bra.
[0085] Although example 3 relates to bras, it will be appreciated
that the above features of the invention are beneficial in a range
of other applications, especially garment manufacture.
[0086] A particular application is the field sports clothing, where
garments having desirable elastic modulus/stretch properties have
been shown to enhance comfort and athletic performance.
Example 4
Tubular Fabric Production from a Flat Fabric
[0087] A further embodiment of the invention relates to the
production of a tubular fabric from a flat (or "open") form of the
fabric of the invention.
[0088] The flat fabric can be formed into a tubular fabric by a
variety of methods. For example, the OB1 AT116 system produced by
Sew Systems Ltd., 53 Iliffe Avenue, Odeby, Leicester, LE5 5LH,
England, provides a convenient automated method whereby flat fabric
is passed through a folder system which takes the single flat strip
and forms it into a tubular form which can be sewn into a
garment.
[0089] As the flat fabric is sewn into the garment, an underwire
(such as a bra wire) can be inserted as the fabric is formed into a
tubular form.
* * * * *