U.S. patent application number 11/076441 was filed with the patent office on 2006-09-14 for continuous constant tension air covering.
Invention is credited to Keith Bumgardner.
Application Number | 20060201129 11/076441 |
Document ID | / |
Family ID | 36969330 |
Filed Date | 2006-09-14 |
United States Patent
Application |
20060201129 |
Kind Code |
A1 |
Bumgardner; Keith |
September 14, 2006 |
Continuous constant tension air covering
Abstract
An air covered yarn is formed by feeding multiple polymeric
yarns along a predetermined path to an air jet. Before reaching the
air jet, the polymeric yarn ends are textured to form covering
yarns. An elastomeric core is also fed along a predetermined path
to the air jet. The covering yarn and elastomeric core are then
pneumatically entangled to form a composite yarn.
Inventors: |
Bumgardner; Keith; (Madison,
NC) |
Correspondence
Address: |
WOMBLE CARLYLE SANDRIDGE & RICE, PLLC
ATTN: PATENT DOCKETING 32ND FLOOR
P.O. BOX 7037
ATLANTA
GA
30357-0037
US
|
Family ID: |
36969330 |
Appl. No.: |
11/076441 |
Filed: |
March 9, 2005 |
Current U.S.
Class: |
57/225 |
Current CPC
Class: |
D02J 1/08 20130101; D02G
3/328 20130101 |
Class at
Publication: |
057/225 |
International
Class: |
D02G 3/36 20060101
D02G003/36 |
Claims
1. A method for forming an air covered yarn, comprising: (a)
feeding polymeric inelastic yarns along a predetermined path; (b)
texturing the polymeric yarns to form a covering yarn; (c) feeding
an untextured elastomeric yarn along a predetermined path at a
substantially constant tension, wherein the constant tension is
maintained by an electronic tension controller; (d) feeding the
covering yarn and the elastomeric yarn through the air jet; and (e)
pneumatically entangling the elastomeric core and the covering yarn
to produce an entangled composite yarn.
2. The method of claim 1 wherein the elastomeric yarn is selected
from the group consisting of spandex, elastane, rubber,
polyetheresters, elastoesters, and elasterell P.
3. The method of claim 1 wherein the elastomeric yarn is
continuously fed from a plurality of supply packages, the supply
packages being spliced together.
4. The method of claim 1 wherein texturing the polymeric yarns
comprises: (a) drawing the polymeric yarns through a heating zone;
(b) cooling the polymeric yarns; and (c) feeding the polymeric
yarns through a false twist unit, wherein the yarns are
crimped.
5. The method of claim 4 wherein the covering yarn and the
elastomeric yarn are fed through the air jet when the crimp in the
textured covering yarn is maximized.
6. The method of claim 4 wherein the polymeric yarn ends are
stretched when drawn through the heating zone.
7. A method for forming an air covered yarn, comprising: (a)
feeding polymeric inelastic yarns along a predetermined path; (b)
texturing the polymeric yarns to form a covering yarn; (c) feeding
an untextured elastomeric yarn along a predetermined path at a
predetermined tension, wherein the elastomeric yarn is continuously
fed from a plurality of supply packages, the supply packages being
spliced together; (d) feeding the covering yarn and the elastomeric
yarn through the air jet; and (e) pneumatically entangling the
elastomeric core and the covering yarn to produce an entangled
composite yarn.
8. The method of claim 7 wherein a substantially constant tension
is maintained in the elastomeric core yarn by an electronic tension
controller while the elastomeric core is being fed along the path
to the air jet.
9. The method of claim 7 wherein the elastomeric yarn is selected
from the group consisting of spandex, elastane, rubber,
polyetheresters, elastoesters, and elasterell P.
10. The method of claim 7 wherein texturing the polymeric yarns
comprises: (a) drawing the polymeric yarns through a heating zone;
(b) cooling the polymeric yarns; and (c) feeding the polymeric
yarns through a false twist unit, wherein the yarns are
crimped.
11. The method of claim 10 wherein the covering yarn and the
elastomeric yarn are fed through the air jet when the crimp in the
textured covering yarn is maximized.
12. The method of claim 10 wherein the polymeric yarn ends are
stretched when drawn through the heating zone.
13. An apparatus for forming an air covered yarn and having a
heating zone, a cooling zone, and a false twist texturizer for
forming an inelastic covering yarn, further comprising: (a) a creel
rack for a plurality of supply packages of elastomeric core
material; (b) an electronic tension controller for controlling the
tension in the elastomeric core; and (c) an air jet for entangling
the covering yarn and the elastomeric core to form a composite air
covered yarn.
14. The apparatus of claim 13 wherein the creel rack is mounted on
the apparatus.
15. The apparatus of claim 13 wherein the creel rack comprises a
plurality of creels positioned on substantially the same level.
16. The apparatus of claim 15 wherein each of the plurality of
creels are angled inwardly toward the electronic tension
controller.
17. The apparatus of claim 13 where the size of the air covered
yarn is not limited by the size of the supply packages of
elastomeric core material.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to the field of
textiles, and, more particularly, to an improved method and an
apparatus for forming air covered yarns.
BACKGROUND OF THE INVENTION
[0002] Air covered yarns, which comprise a combination of elastic
and inelastic materials, are incorporated widely in the apparel
industry in fabrics that require performance stretch and recovery.
The process for forming these yarns typically requires two steps.
First, two or more continuous filaments of nylon, polyester, or
other suitable inelastic polymeric filaments are fed from creel
racks through a texturing machine, such as a false-twist texturing
machine. The filaments are typically drawn through heating zones
where they are stretched, and then cooled, before being routed
through a friction unit. The friction unit imparts a crimp, or
twist, to the filaments. The cooled, textured filaments are then
plied and wound on a take-up roll, or package. The take-up packages
are doffed or removed and taken to a separate location in the
plant, or to a remote facility, for further processing.
[0003] The textured/false twisted polymeric filaments are then
combined with a continuous filament of elastic, such as spandex,
and fed through an air jet where they are entangled. A conventional
air covering machine is used. The entangled composite
inelastic/elastic yarn is then wound on a take-up package and
prepared for shipment to a customer.
[0004] There are difficulties with the existing processes. First,
the air covered yarn must normally be produced in at least two
steps and, most likely, in two separate plant locations. Second, on
conventional air covering machines, the elastic spandex filaments
or yarn are fed from a single package for air covering with the
inelastic filament yarns. This means that the air covering machine
must be stopped and a new creel installed each time the spandex
package is depleted. As will be appreciated, this results in
frequent and undesirable production stops. Additionally, because
spandex is elastic, the tension of the spandex feed inherently
varies from the beginning of the spandex package to the end of the
spandex package. This can result in a final air covered yarn with
an undesirable variable tension from one end of the yarn take-up
package to the other. Further, when formed as a two-step process,
several months can elapse between the time that the textured nylon
packages are produced and the time that they are used in the air
covering process. Since textured yarns lose some of their textured
qualities (crimp, twist, etc.) over time, an inconsistent quality
results in the final yarn, as the age of the textured product in
use varies.
[0005] For various reasons, textile machine manufacturers have
attempted to combine the two steps into single machines, but these
combination machines have failed to address the undesirable
production stops for changing the depleted spandex packages, or the
variability in the tension of the spandex feed.
[0006] Despite the ability of those of ordinary skill in the art to
identify various ways to lengthen production runs on air covering
machines and to more efficiently schedule the manufacture of the
false twisted yarn component for air covered yarns, there remains a
need for a method to optimize the manufacture and quality of air
covered yarns.
SUMMARY OF THE INVENTION
[0007] A method for forming an air covered yarn comprises feeding
polymeric inelastic yarns along a predetermined path, texturing the
polymeric yarns to form a covering yarn, feeding an untextured
elastomeric yarn along a predetermined path at a substantially
constant tension, wherein the constant tension is maintained by an
electronic tension controller, feeding the covering yarn and the
elastomeric yarn through the air jet, and pneumatically entangling
the elastomeric core and the covering yarn to produce an entangled
composite yarn.
[0008] This invention also includes a method for forming an air
covered yarn comprising multiple steps, including feeding polymeric
inelastic yarns along a predetermined path, texturing the polymeric
yarns to form a covering yarn, feeding an untextured elastomeric
yarn along a predetermined path at a predetermined tension, wherein
the elastomeric yarn is continuously fed from a plurality of supply
packages, feeding the covering yarn and the elastomeric yarn
through the air jet; and pneumatically entangling the elastomeric
core and the covering yarn to produce an entangled composite yarn.
In a preferred embodiment, the supply packages are spliced together
to allow for continuous feeding.
[0009] These and other features of the present invention will
become apparent to those skilled in the art after a reading of the
following description of the preferred embodiments when considered
in conjunction with the drawings. It should be understood that both
the foregoing brief description and the following detailed
description are exemplary and explanatory only and are not
restrictive of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a schematic of the prior art method for texturing
(false twisting) a polymeric yarn.
[0011] FIG. 2 is a schematic of the prior art method for forming an
air covered yarn.
[0012] FIG. 3 is a schematic of the air covering method of the
present invention.
[0013] FIG. 4 is a front perspective view of the air covering
apparatus of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] Certain exemplary embodiments of the present invention are
described below and illustrated in the attached Figures. The
embodiments described are only for purposes of illustrating the
present invention and should not be interpreted as limiting the
scope of the invention, which, of course, is limited only by the
claims below. Other embodiments of the invention, and certain
modifications and improvements of the described embodiments, will
occur to those skilled in the art, and all such alternate
embodiments, modifications and improvements are within the scope of
the present invention.
[0015] One embodiment of the present invention is directed to a
method for forming an air covered yarn comprising an elastic
component and a polymeric, inelastic component.
[0016] As described herein:
[0017] "POY" is an acronym for "partially oriented yarns" and is
intended to refer to filament yarns in which the draw ratio is less
than normal, resulting in only a partial longitudinal orientation
of the polymer molecules.
[0018] "Drawing" refers to the process of increasing the length per
unit weight of the filaments in order to orient the yarn to achieve
desired physical properties.
[0019] "Texturizing" refers to the process where one or more
continuous filaments or yarns are modified to obtain bulk, twist,
or additional strength.
[0020] "False Twist Texturizing" refers to a continuous method for
producing textured yarns that utilizes simultaneous twisting,
heating, and untwisting.
[0021] "Elastomeric fibers" refers to continuous filaments which
have a break elongation in excess of 100 percent independent of any
crimp.
[0022] "Inelastic fibers" refers to fibers that do not stretch and
recover to the same extent as elastomeric fibers.
[0023] "Air covering (entanglement)," also known in the art as
"intermingling", refers to the use of one or more air jets to
create turbulence to entangle filaments of continuous filament
yarns.
[0024] The method of the present invention produces an air covered,
or entangled, composite yarn that is produced on a single textile
machine in a single production process, wherein the tension of a
continuously fed elastomeric yarn is maintained constant.
[0025] For many years, elastomeric fibers, such as spandex, have
been covered or entangled with relatively inelastic fibers to
facilitate processing for knitting and weaving of fabrics that
require performance stretch and recovery. The inelastic fibers also
provide the elastic composite yarns with acceptable surface
characteristics, e.g., hand, for various end uses.
[0026] A commonly used processes for forming covered, or entangled,
elastomeric yarns requires at least two separate production steps.
As a first step, the inelastic yarn must be textured. FIG. 1 is
illustrative of one type of conventional process and machine for
completing the initial texturing of one or more inelastic yarns,
such as polyester or nylon. These inelastic yarns initially are
formed as continuously spun filaments of synthetic polymeric
materials with deniers typically ranging from about 20 to about
300. In their initial spun states, they are commonly know as POY.
POY, however, is not preferred in the production of yarns or
fabrics since it lacks the finish or handle characteristics that
are desired for apparel. Thus, POY must first be textured. FIG. 1
illustrates one such process for texturing POY. The machine, shown
schematically, is illustrative of one of the several machines
manufactured by Barmag, AG of Germany. In particular, the machine
illustrated in FIG. 1 is a false twist texturing machine. On this
machine, a frame 110 supports several (3 are shown) creels, or
packages, 113. Each creel 113 holds a take-off supply package 115
of untextured nylon POY. The take-off supply packages 115 each
provide a single or multi-filament yarn which is fed in parallel
with other yarns to form an initially untextured yarn 120.
[0027] The multi-filament yarn 120 may pass over several sets of
guides or rollers, depending upon the design and actual
configuration of the particular false twist texturing machine. In
the exemplary machine/process of FIG. 1, the machine comprises feed
rollers 117, 118 and an upper guide roller 119. The upper guide
roller 119 aligns and directs the multiple yarns comprising yarn
120 downwardly through a heating zone 130. Shown in FIG. 1 as a
heating tube, the heating zone 130 may comprise a plate, enclosure,
or semi-enclosure. As those skilled in the art will appreciate, the
heating zone 130 may take numerous forms, shapes, and lengths,
depending upon the material(s) being textured and the temperature
limitations on the synthetic materials.
[0028] The multi-filament yarns 120 are drawn typically through the
heating zone 130 at a prescribed tension, wherein the filaments are
stretched. The temperature in the heating zone is between about 130
degrees Fahrenheit and 500 degrees Fahrenheit. The yarns 120 are
fed at a tension of between about 5 grams and about 100 grams. Upon
exiting the heating zone 130, the multi-filament yarn 120 is drawn
through a cooling zone 140 where air is circulated at ambient
temperature to cool the yarn 120 to a point where further
downstream processing may be completed.
[0029] The next step in the texturing process is false twisting.
The yarn 120 is fed through a false twist unit 150, as are known in
the art. The false twist unit 150 typically comprises at least one
spindle of offset discs moving in identical directions in several
axes. One suitable false twist unit is a Type 8 unit, available
from Barmag AG of Germany. This produces a yarn 120 having a
helical, or spring-like, structure, also known as crimping. As the
yarn 120 exits the false twist unit, the amount of crimp in the
yarn 120 is maximized. The textured yarn 120 is then wound to form
a textured nylon package 165 that is mounted on a take-up
collection roller 170. The textured nylon package 165 is
subsequently removed and stored until needed. As will be
appreciated, winding the yarn 120 on the package 165, handling of
the package 165, and subsequent storage of the package 165 result
in some loss/reduction of crimp in the yarn 120.
[0030] Turning now to FIG. 2, the second step of a traditional
manufacturing process for an air-covered yarn can include an
air-entanglement machine, shown generally as 200. The machine 200
shown in FIG. 2 is an illustrative representation of an ICBT JD800
air covering machine, available from Rieter ICBT of Lyon, France. A
textured nylon package 165 is mounted on a creel 210 to feed the
textured nylon yarn 120 to the air jet covering process as the
covering, or entangling, yarn. A supply package of elastomeric yarn
225 is mounted on a creel 220 to supply continuous filaments 228 of
the elastomeric yarn. The spandex filaments may range widely in
size, between 10 and about 2,240 denier. In the air covering
machine 200 shown in FIG. 2, the tension of the elastomeric
(spandex) yarn must be controlled; however, on machines that are
currently in commercial operation, the tension is mechanically
controlled by a system of one or more rollers 223 that are adjusted
by formulae to a predetermined speed ratio, as is known in the art
as "drafting" the elastomer. Unfortunately, however, and as will be
appreciated in the art, as the supply package 225 of elastomeric
yarn becomes smaller, the tension in the yarn 228 will vary, when
controlled solely by a mechanical ratio means. This, of course,
results in a non-uniform elasticity in the composite yarn from the
beginning to the end of the production run.
[0031] Yarns 120 and 228 are subsequently, and simultaneously, fed
through a series of rollers 230 and 240 and into the air jet
entangler 250. In one embodiment, the air jet entangler is Model
No. E-16V, available from International Machinery Sales of
Winston-Salem, N.C. The nylon 120 and spandex 228 are entangled (at
ambient temperature) to form a composite covered yarn 280. The
composite covered yarn 280 is subsequently wound by means of
take-up rollers 260 onto take-up packages 270, held by stationary
creels 275. The final composite covered yarn 280 is then ready for
storage and/or shipment to a customer for incorporation into fabric
and items of apparel.
[0032] Turning now to the views of FIGS. 3 and 4, the method and
apparatus according to the present invention are illustrated. While
the prior art processes described above have described the
production of composite yarns on at least two different machines
and at two different plant locations, the method of the present
invention is completed in a one step, consolidated, process wherein
the tension of a continuously fed spandex feed is maintained
constant.
[0033] As illustrated in FIGS. 3 and 4, a consolidated texturing
and air covering machine 300 is constructed. A novel spandex creel
rack assembly 310 is combined with a modified polymeric yarn
texturing machine. In the particular embodiment shown and described
herein, the texturing machine so modified is one of several
machines manufactured by Barmag AG of Reimscheid, Germany. The
creel rack assembly 310 is installed adjacent to the frame of the
texturing machine so that the spandex fiber can be more easily fed
to an electronic tension controller 320, described below, that is
mounted on the frame. The creel rack assembly 310 includes a frame
312 to which multiple creels 315 are affixed for holding multiple
supply packages 225 of an elastomeric (spandex) yarn. As shown in
FIG. 3, in particular, the creels 315 are positioned so that the
supply packages 225 may be tied together. Additional creels 319 may
be provided as shown in FIG. 3 for holding a supply of fresh supply
packages 226; however, the spandex is fed only from supply packages
on creels located at the level of creel 315.
[0034] The creels 315 of the apparatus shown in FIGS. 3 and 4 are
positioned approximately level with one another, and equidistant
from the electronic tension controller 320, so that the supply
packages 225 of the spandex yarns/filaments may be spliced together
for continuous, un-interrupted air covering operations. This
permits the machine operators to more easily change out exhausted
supply packages with new supply packages. Further, since the supply
packages 225 are equidistant from the tensioner 320, there is no
significant change in tension from one package 225 to another
package 225 during changeover of the packages 225.
[0035] As shown in FIGS. 3 and 4, the supply packages 225 may be
tied together at points 317 so that when one package 225 is
exhausted, the opposed supply package will then be drawn. As will
be appreciated, during the switchover from one package to another,
the tension in the feed will temporarily vary slightly, and this
variance is overcome by electronic tension control. The spandex
supply packages 225 are configured/spooled such that each supply
package 225 has a lead 225a and a tail 225b. That is, the tail 225b
of a first supply package 225 is manually tied to the lead 225a of
a second supply package. In addition, the creels 315 and the
spandex supply packages 225 are angled inwardly toward one another
so that the elastomeric yarns may be continuously fed "over-end"
with respect to each supply package 225. "Over-end" feeding means
that the yarns are fed from the supply package 225 at an angle to
the surface of the supply package, instead of being unrolled
directly from the package. Whereas the prior art method required
that the production process be halted for the change-outs of
exhausted supply packages, the present invention permits packages
to be continuously replaced and tied together so that the
production process does not have to be interrupted. For
convenience, the leads 226a and tails 226b are illustrated on the
spare supply packages 226.
[0036] A modified apparatus permits spandex rolls to be "spliced"
together so that production does not have to be halted for the
changing of the spandex packages. With multiple packages of spandex
positioned on the same level and tied together, a constant supply
of elastomer is assured in the process. These improvements
contribute to a more cost effective, consistent, and higher quality
final yarn product. A feature of the present invention is that the
resultant air covered yarn is not limited by the size of a single
supply packages of elastomeric core material.
[0037] Having been fed from the supply packages 225, the
elastomeric yarn 228 is next fed through an electronic tension
controller 320. Electronic tension controllers are known in the
art, but heretofore have not been used for air covered yarn
production. One tension controller 320 that has been determined to
be suitably used in the textile machine 300 of the present
invention is Model No. MF, available from BTSR of Vareso, Italy.
The electronic tension controller 320 also comprises tension
sensors 322 which provide continuous electronic feedback to the
tension controller 320 to maintain a constant tension in the
elastomeric yarn 228, regardless of the amount of yarn remaining on
the supply package 225.
[0038] This electronic tension controller and feeder system 320 use
a programmable feeder unit to deliver the spandex at a consistent
tension through out the spandex package and from one spandex supply
package to another. The sensors 322 continuously monitor the
programmed tension and, in conjunction with programmable controller
320, may also used to monitor the length and consumption of any
given yarn, including spandex. Accordingly, the electronic tension
controller 320 and sensors 322 provide a continuous quality control
function of the programmed yarn process parameters, which in the
present invention can be tension. Where a tolerance in the tension
value is permitted, the programmable controller ensures that the
tension in the yarn feed remains within the prescribed tolerance.
As will be appreciated, the electronics (circuitry and software,
not shown) within the tension controller 320 are compact, which
facilitates installation on the combined texturing and air covering
machine 300. Depending upon the particular application for the air
covered yarn, the tension in the spandex may be maintained between
about 0.5 to about 100 grams.
[0039] Upon exiting the tension controller 320, the spandex 228 is
fed over at least one feed guide 325 so that it can be precisely
fed to the air jet entangler 330. Simultaneously with the
introduction of the spandex 228 to the air jet 330, the textured
nylon yarn 120 is introduced into the air jet 330 in parallel to
the spandex 228. As described above, the textured nylon 120 is
formed in the same manner as on unmodified texturing machine 100.
Both yarns 228 and 120 are fed through the air jet 330 wherein the
yarns are entangled to form a composite yarn 380. The composite air
covered yarn 380 is further fed over at least one set of rollers
340 before being taken up on a final yarn package (not shown).
Unlike the process of the present invention, wherein the textured
nylon yarn is fed into the air jet at an elevated temperature,
i.e., still cooling, for entanglement with the spandex, the prior
art process described above has required two distinct processes
involving the composite of yarns textured much earlier. Since the
entanglement with the spandex occurs as the textured nylon is
exiting the false twist unit, the textured nylon crimp is
maximized, and the yarns are tacked together, i.e., bonded, at more
points along their entanglement. More specifically, the inventors
have observed that the resulting yarn has a smaller diameter,
increased uniformity of entanglement, and a higher retention of
entanglement during subsequent processing. While the textured nylon
eventually will cool to room or ambient temperature, entangling the
yarns prior to reaching ambient temperature provides the advantages
stated herein. In most textile manufacturing plants, ambient
temperature is between about 76 degrees Fahrenheit and 80 degrees
Fahrenheit.
[0040] Various types of elastomeric yarn can be used, such as
spandex, elastane, rubber, polyetheresters, elastoesters, and
elasterell P.
[0041] Composite yarns produced in accordance with the present
invention are described in the examples below:
EXAMPLES
[0042] TABLE-US-00001 Final Construction/ Nylon Denier/ Spandex
Composite Run Construction Denier Denier Use 1 2/70/34 20 158 Socks
2 1/150/68 20 160 Socks 3 2/70/34 10 154 Socks 4 1/70/34 70 100
Fleece Fabric
[0043] As those skilled in the art will appreciate from the
examples above, the percentage of spandex in the final composite
yarn and the denier of the spandex may be varied for forming yarns
having different end uses. By splicing the spandex packages
together, and thus continuously feeding the spandex to the air jet,
the size (diameter) of the take-up package of the composite yarn is
not limited by a higher denier spandex or a higher percentage of
spandex in the composite yarn.
[0044] Although the present invention has been described with
preferred embodiments, it is to be understood that modifications
and variations may be utilized without departing from the spirit
and scope of the invention, as those skilled in the art will
readily understand. Such modifications and variations are
considered to be within the purview and scope of the appended
claims and their equivalents.
* * * * *