Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02227123 1998-03-26
FALSE-TWISTING WARPING
The present invention relates to a method for preparing warp
in fabric and warp knitting producton.
Traditional method for preparing warp is that,before the
yarns or filaments, no matter whether they experience sizing
process,are used as warp,they are first wound into a warp beam in
such a way that the yarns or filaments are arranged to be parallel
to each other and form a sheet before being wound into warp
beam, then the beam is mounted on the beam support in the loom(the
case is same for warp knitting machine),after that the yarns or
filaments are, as a parallel sheet, fed to the loom, by either being
negatively pulled, in which case the brake is usually used to apply
pressure to the beam, or the beam's being positively driven through
a set of mechanism,or combination of both.In all the
situations, the warp beam should turn in order to feed the warp.
This traditional method has several disadvantages. First, when
the warp beam runs out,the loom should stop and wait for people to
replace with a full warp beam and tie the warp before continues
running. This sort of waiting constitutes a loss of production
efficiency. Second, warp tension controll requires sophisticated
mechanism and electrical devi.ce.Because,in order to achieve even
feeding of warp,the speed of the warp beam should be controlled to
increase accordingly when t:he warp beam goes from full to
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empty. This kind of controll ha;s been proven difficult in many
situations and causes not only the quality problem, but further
loss of production efficiency.Third,when a yarn or filament is
broken inside the warp beam, it is often hard to find the broken
end.And this frequently results in a messed warp beam and is
another source of quality problem and efficiency loss.
Another method of warp preparation, which is known as LOCKER
BAND system and can only find its use in safebelt production, uses
the narrow needle loom to produce a kind of semiproduct which
serves as warp and is known as locker band. The locker band is, in
fact,a kind of narrow fabric with a very loose weft density of 2-5
picks/inch.The warp which is required to form the locker band is
fed directly from the cone creel. Because one edge of locker band
is knitting edge, the weft can be drawn from the locker band. After
the weft has been drawn from the locker band through a device in
the loom,there is only warp left,which is fed to narrow loom as
traditional warp.Although this method can eliminate the need of
stopping loom while tying locker band and make possible a very
constant warp tension,it has two big drawbacks.One is that the
output of locker band is very low, it is very hard for the output
to exceed 15 meters/minute.Second one is that, when the locker band
is woven,the warp experiences severe vibration and
friction,therefore the mechanical property of the warp will be
damaged to a greater or less extent.For the materials which are
fine or filamenting-sensitive, the warp breakage in weaving process
will increase considerably. As a matter of fact, the warp
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experiences weaving process twice when they are woven into final
product, therefore this method is limited to production of narrow
fabric with strong yarn and high weft density.
It is desirable to have a method of warp preparation, which
can eliminate the need of stopping loom while warp tying and more
conveniently keep the warp tension constant,make the broken end
finding easier, and in the mean time, doesn't sacrifice the warping
efficiency and the range of its application.
The present invention consists of a method for preparing
warp in fabric production, which would increase the weaving
efficiency and improve product quality, and comprises three steps.
In the first step,the yarns or filaments are gathered into a
guide hole to form the shape of the rope, and are held through
pairs of rollers which apply pressure on the rope warp(i.e. the
gathered yarns or filaments) and can control movement of the rope
warp.The yarns or filaments before being gathered may come the
cone creel, or the sizing machine.
In the second step of the invention, the rope warp is applied
false twist and stored into a stationary container. The container
~ may be the usual empty beam,or the beam without the flange on one
side, or simply a cone object.
In one embodiment of this invention, through a rope warp guide
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which rotates around the stationary container, the rope warp
obtains the false twist and is wound into the stationary
container.The movement of the rope warp guide is arranged to be
that of combination of both rotation and parallel movement to the
axis of the container.
In the third step of thi;a invention, the falsely-twisted rope
warp container is mounted in the loom and the falsely-twisted rope
warp is unwound axially from the stationary container through
another pairs of pressure rollers in the loom and is fed to
loom. As the direction of warp movement in this step is exactly
opposite to that in step one and step two of this invention, the
false twist formed in step two will disappear and the
falsely-twisted rope warp can. be restored to its traditional
shape:a parallel sheet, and serve as usual warp.
When the falsely-twisted rope warp is stored in the step
two, we can leave outside the container a length of rope warp which
can be tied to another full container even when the loom is
running, because the containers are always stationary.
In the third step,the feeding speed of the rope warp is
totally controlled through the pressure rollers which hold and
move the rope warp,therefore we simply need to set the speed of
the rollers as required, the feeding speed of the rope warp would
not change,no matter whether the container is full or close to
empty. Thus, the warp tension is kept constant.
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If a yarn or filament is broken, the twist in the rope warp
tends to keep the broken end in fixed position,and the broken end
will follow adjacent ends and automatically appear after it has
left the pressure rollers, therefore the warp wouldn't tend to get.
messed up.
In the second step of this invention,when the container i~;
full, if the rope warp isn't cut and is carefully handled so that
the rope warp is positioned in another errpty container and then
the false-twisting processing is resumed. So, we can put together
two or more containers wii:h uncut rope warp between each
other, therefore the volume of continuous warp can be several fold;
increased without the need of increasing the size of the
container.This arrangement will reduce the need of warp tying and
further increases weaving efficiency.
In drawings which illustrate embodiments of the invention.
Figurel shows how the false twist is formed.
Figure2 shows how the falsely-twisted rope warp is restored
to traditional warp.
Referring to drawings,the present invention consists of a
method for preparing warp. The method comprises three steps.
First, the yarns or filamentsl which may come from the cone
creel or from the sizing mach:ine,are passed through the reed2,then
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gathered into guide3 and are held through the pressure rollersn
which are also arranged to control the movement of the gathered
yarns or filaments(rope warp). The speed of rope warp is controlled
through rollers9.The guide3 p_s preferable to be open so that the
rope warp can be easily put through and taken out, and the thread
which is placed in rope warp to separate one end from each other
when necessary can easily pass through rollers9.The number of warp
ends is preferable to be less than 1000,depending on the count of
the warp end. For this reason, this method is preferable to be used
in narrow fabric and narrow warp knitting production, or broad
fabric where section warping is used.
Second,when the rope warp is delivered from rollers4,it i~;
wound into a stationary containers through the rope warp guideEs
which is constructed to be able to rotate around and traverse'
along the axis of the stationary container5.The rotation movement.
of the guide6 may be achieved through a belt which is arranged to
be able to slide on pulley which drives the guide6,when the
feeding speed of rope warp from roller4 limits the speed of the
guide6.That is, the driving force of the guide 6 is preferably
friction force.The transversal movement of the guide6 may be
achieved through a cam so that: the rope warp can be wound into the
containers in the desired shape. The container may be the usual.
beam,or modified beam with only one flange on one side,or simply a
cone objector something else which can be fixed in position and
accommodate the rope warp and cann't cause rope warp messed
up.When the rope warp is wound into the container5,a length of
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rope warp which contains the separation thread is left outside the
containers.
Third,the full container7a is mounted in a loom.When the
falsely-twisted rope warp is axially unwound from the stationary
container7a,through another pressure rollers8 which hold and
control movement of rope warp, the false twist in rope warp will
disappear,and the rope warp passes through the rollers8 and is
separated through another reed9 in the loom. In this way, the rope
warp is restored to traditional warp.
As the containers are always kept stationary,the length of
rope warp left outside container7b can be tied to another
containerl0,even when loom is running. During the process, special
care should be taken to ensure that real twist shall not be added
to the rope warp.
When the containers in step2 becomes full,we can leave the
rope warp uncut,and position it in another empty container and
then resume the false-twisting processing.In this way,we can put
together 2 or more containers. with uncut rope warp between each
other(for example:7a and 7b),therefore the volume of continuous
warp can be many folds increased.
Because the feeding speed of rope warp is totally controlled
through rollers8 in the loom,we simply need to set the speed of
rollers8 as required,the feeding speed of rope warp would not
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change, no matter whether the container7a is full or not, Thus, the
warp tension is kept constant.
If one end is broken inside the container7a,the twist tends
to keep the broken end in fixed position and the broken end will
follow adjacent ends and automatically appear after it leaves the
rollers8,the warp wouldn't tend to get messed up.
Although only a single embodiment of the present invention
has been described and illustrated,the present invention is not
limited to the features of this embodiment,but includes all
variations and modifications within the scope of the claims.
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