U.S. patent application number 12/222133 was filed with the patent office on 2010-02-04 for method and apparatus for manufacturing slalom false twisting on ring yarn.
This patent application is currently assigned to The Hong Kong Polytechnic University. Invention is credited to Jie Feng, Tao Hua, Xiaoming Tao, Bingang Xu.
Application Number | 20100024376 12/222133 |
Document ID | / |
Family ID | 41606875 |
Filed Date | 2010-02-04 |
United States Patent
Application |
20100024376 |
Kind Code |
A1 |
Tao; Xiaoming ; et
al. |
February 4, 2010 |
Method and apparatus for manufacturing slalom false twisting on
ring yarn
Abstract
In a process for manufacturing a singles ring yarn, a method and
apparatus is invented which utilizes double belts as a false twist
device and incorporates it in the conventional ring spinning
machine for producing a singles ring yarn. In this invention, a
double-belts is applied thus two twisting points, instead of one
twisting point, are adopted for the yarn false twisting to improve
the false twist efficiency. Accordingly, a ratio of the velocity of
the belt to the delivery speed of the yarn is controlled and the
wrapping angle of the yarn on the belts is adjusted in order to
obtain the desired property of the final singles ring yarn. The
said invention can enhance the strength of fiber strand at the
spinning triangle and thus ensure the yarns spun in a normal
condition at low twist multipliers, which is unable to be obtained
by the conventional ring spinning machine. The method produces
yarns with good strength, less hairiness and lower yarn residual
torque at low twist level and endows the resultant fabric with
softer handle, low spirality as well as clear and smooth surface
appearance. The method and apparatus has the advantages of easy
yarn piecing-up and doffing process, low spinning end-breakage when
using ordinary raw materials and low cost of investment and
maintenance, which not only is able to meet the commercial
requirements of the large-scale production in the textile industry
but also possesses a high false twist efficiency.
Inventors: |
Tao; Xiaoming; (Kowloon,
CN) ; Hua; Tao; (Kowloon, CN) ; Xu;
Bingang; (Kowloon, CN) ; Feng; Jie; (Kowloon,
CN) |
Correspondence
Address: |
BLANCHARD & ASSOCIATES
566 WEST ADAMS STREET, SUITE 600
CHICAGO
IL
60661
US
|
Assignee: |
The Hong Kong Polytechnic
University
Hong Kong
HK
|
Family ID: |
41606875 |
Appl. No.: |
12/222133 |
Filed: |
August 4, 2008 |
Current U.S.
Class: |
57/333 ;
57/315 |
Current CPC
Class: |
D01H 7/923 20130101;
D02G 3/328 20130101; D01H 5/28 20130101; D01H 1/11 20130101; D01H
13/08 20130101 |
Class at
Publication: |
57/333 ;
57/315 |
International
Class: |
D02G 1/00 20060101
D02G001/00; D01H 5/28 20060101 D01H005/28 |
Claims
1. A method for producing singles ring yarns, comprising: imparting
a first high twist to a strand of traveling drafted fibers emerged
from the front-drafting-roller nip with the upper belt of a false
twist device for producing a preliminary singles yarn, wherein the
belt travels at the velocity of the belt for twisting the fibers
and thus the strength of fiber strand is enhanced at the spinning
triangle when a low twist level is adopted in the final singles
yarn; immediately after the false twist step by the upper belt
severed as the first twisting point, imparting a joint twist of a
second twist in the same direction as the first twist and a third
twist in the reversed direction to the preliminary singles yarn for
the production of a final singles ring yarn, wherein the second
twist is produced by a running of the lower belt on the yarn,
wherein the third twist results in correspondence to the first
twist by a running of the upper belt on the yarn; immediately after
the false twist step by the lower belt severed as the second
twisting point, imparting a joint twist of a forth twist in the
same direction as the second twist, and a fifth twist in the
reversed direction to the preliminary singles yarn for the
production of a final singles ring yarn, wherein the forth twist is
produced by a rotatable take-up package of the ring spinning
machine onto which the final singles yarn is drawn, wherein the
fifth twist results in correspondence to the second twist by a
running of the lower belt on the yarn; then the final singles yarn
was drawn onto the take-up package; running the upper and lower
belts in the opposite directions with the same velocity; and
controlling a ratio of the velocity of the belts to the delivery
speed of the yarn and the wrapping angles of the yarn on the
double-belts for controlling the false twist efficiency for yarn
and thus the yarn property.
2. The method for producing singles ring yarns of claim 1, wherein
the yarn interacts with the false twisting device in the form of
two false twisting points and in fact the yarn is false twisted by
the torque generated by running the double belts in opposite
travelling directions with the same velocity.
3. The method for producing singles ring yarns of claim 1, wherein
the geometry interrelation of the yarn, the upper belt and lower
belt is important in determining the optimal adaptation of the
double belts false twist device to the desired impartation of false
twist, and in optimizing the yarn tension conditions and false
twist efficiency.
4. The method for producing singles ring yarns of claim 1, wherein
the residual torque and other yarn properties of the final singles
ring yarn are controlled by controlling the friction between the
yarn and the surface of the upper belt and lower belt, and the
ratio of the velocity of the belts to the delivery speed of the
yarn.
5. The method for producing singles ring yarns of claim 1, wherein
the high false twist efficiency that utilizes double belts as a
false twist device is provided during the yarn spinning process,
and wherein the ordinary raw materials can be used to produce
singles ring yarn due to the improved strength of fiber strand in
the spinning triangle and the improved fiber inter-friction within
the yarn at a low twist level.
6. An alternative method for producing singles ring yarns,
comprising: imparting a first high twist to a strand of traveling
drafted fibers emerged from the front-drafting-roller nip with a
nip false twister consisting of the two belts in close position for
producing a preliminary singles yarn, wherein the false twist
device provides one twisting point instead of two twist points for
a yarn, wherein the false twist device provides more false twist
efficiency than that of one belt false twist device, and wherein
the yarn is false twisted by the torque generated by running the
double belts in opposite travelling directions with the same
velocity.
7. An another alternative method for producing singles ring yarns,
comprising: imparting a first high twist to a strand of traveling
drafted fibers emerged from the front-drafting-roller nip with
double belts running in cross direction and regulation block for
the friction adjusting between the yarn and belts for producing a
preliminary singles yarn, wherein a yarn is advanced along the line
which bisects the angle formed by the two crossing belts, i.e., the
false twisting zone.
8. The method for producing singles ring yarns of claim 7, wherein
the belts are pressed against the yarn in the area of the twisting
zone by the regulation block which consists of spring and shim
assembly, and wherein the regulation block can adjust the friction
between the yarn and belts, improve the control of fiber movement
during the false twisting of the yarn as well as provide a easier
yarn piecing process.
9. An apparatus for producing singles ring yarns, comprising: the
upper belt of a false twist device travelling at the velocity of
the belt imparting a first high twist to a strand of travelling
drafted fibers emerged from the front drafting-roller nip such that
a preliminary singles yarn is produced; the lower belt of a false
twist device travelling at the same velocity as the upper belt
imparting a second twist in the same direction as the first twist
to a preliminary singles yarn emerged from the upper belt such that
a further preliminary singles yarn is produced; a rotatable take-up
package onto which the final singles yarn is drawn imparting a
fourth twist in the same direction as the first twist and second
twist to a preliminary singles yarn emerged from the lower belt
such that final singles yarn is produced, wherein the double belt
travels at the velocity of the belt for twisting the fibers and
thus the strength of fiber strand is enhanced at the spinning
triangle when a low twist level is adopted in the final singles
yarn, wherein a joint twist of a second twist in the same direction
as the first twist and a third twist in the reversed direction are
imparted to the preliminary singles yarn for the production of a
final singles ring yarn, wherein the second twist is produced by a
running of the lower belt on the yarn, wherein the third twist
results in correspondence to the first twist by a running of the
upper belt on the yarn, wherein the yarn was drawn onto the take-up
package at the delivery speed of the yarn, wherein a joint twist of
a forth twist in the same direction as the second twist and a fifth
twist in the reversed direction are imparted to the preliminary
singles yarn for the production of a final singles ring yarn,
wherein the forth twist is produced by a rotatable take-up package
onto which the final singles yarn is drawn, and wherein the fifth
twist results in correspondence to the second twist by a running of
the lower belt on the yarn, wherein the ratio of the velocity of
the belts to the delivery speed of the yarn can be controllable and
the wrapping angle of the yarn on the belts is adjustable such that
the false twist efficiency and the yarn property can be
adjusted.
10. The apparatus of claim 9, wherein the false twisting device
mainly comprise the double belts severed as two false twisting
points when the double belts travel in opposite travelling
directions with the same velocity.
11. The apparatus of claim 9, wherein the belt guides and
pressuring discs are used to control the belts movement, as well as
adjust the geometry interrelations of the yarn and the upper belt
and lower belt and the tension of the belts.
12. An alternative apparatus for producing singles ring yarns,
comprising: a nip false twister consisting of the two belts in
close position imparting a first high twist to a strand of
traveling drafted fibers emerged from the front-drafting-roller nip
for producing a preliminary singles yarn, wherein the false twist
device provides one twisting point instead of two twist points for
a yarn, and wherein the yarn is false twisted by the torque
generated by running the double belts in opposite travelling
directions with the same velocity.
13. An another alternative apparatus for producing singles ring
yarn, comprising: a false twist device with double belts running in
cross direction imparting a first high twist to a strand of
traveling drafted fibers emerged from the front-drafting-roller for
producing a preliminary singles yarn, wherein a yarn is advanced
along the line which bisects the angle formed by the two crossing
belts, i.e., the false twisting zone.
14. The apparatus of claim 13, wherein the belts are pressed
against the yarn in the area of the twisting zone by the regulation
block which consists of spring and shim assembly, and wherein the
regulation block can adjust the friction between the yarn and
belts, improve the control of fiber movement during the false
twisting of the yarn as well as provide a easier yarn piecing
process.
15. The apparatus of claim 9, wherein ten different types of belt
shapes such as round shape, elliptical shape and with/without
hollow inside the belt for the false twist device can be used for
the yarn false twisting process and which one is to be used mainly
depends on the required false twisting effects.
16. The apparatus of claim 12, wherein ten different types of belt
shapes such as round shape, elliptical shape and with/without
hollow inside the belt for the false twist device can be used for
the yarn false twisting process and which one is to be used mainly
depends on the required false twisting effects.
17. The apparatus of claim 13, wherein ten different types of belt
shapes such as round shape, elliptical shape and with/without
hollow inside the belt for the false twist device can be used for
the yarn false twisting process and which one is to be used mainly
depends on the required false twisting effects.
Description
BACKGROUND
[0001] 1. Field of the Invention
[0002] The present invention relates to spinning technology for the
production of a singles ring yarn. The invention is particularly
concerned with a method and apparatus that utilizes a false twist
device with two false twisting points to nip yarns between double
belts and incorporates it in the conventional ring spinning machine
to improve yarn property and fabric performance as well as the
efficiency of false twist and easiness of the operation. The false
twist efficiency for yarn and thus the property of the final
singles ring yarn can be controlled.
[0003] 2. Background of the Invention
[0004] Twisting is an important step of short fiber spinning. In
this process, the yarns, are elastically twisted and transformed to
attain sufficient strength, wear resistance and smoothness.
However, as a negative effect, a large amount of residual torque or
twist liveliness is also brought about in the yarns simultaneously.
Such twist liveliness of the yarns renders a significant influence
on the possessing quality of the latter products. For example, if
yarns with twist liveliness are used for knitting, loops of the
fabric will lose their balance because of the residual torque in
the yarns. In order to attain the natural structure with the
minimum energy condition, the loops tend to rotate to release the
internal torsion stress. As a result, one end of the loops will
tilt and protrude from the fabric surface, while the other end will
stay inside the fabric. Such deformation of the loops will increase
the spirality of the fabric, i.e., a deformation similar to the rib
effect, which should be prevented to the utmost in the spinning
industry. Thus, the balancing of torque inside the yarns is
particularly important.
[0005] Staple yarns are made from a large quantity of fibers
bounded by their friction inbetween. Hence, the residual torque of
the yarns or the spirality of the fabric is mainly affected by said
characteristic of the fibers, such as the type and cross sectional
shape of the fibers, the polymerizing manner of the fibers and the
internal structure of the yarns, etc.
[0006] First of all, different types of fibers have a different
modulus and cross sectional shape, thus lead to different degree of
stress in the yarns. In the cotton/polyester blended yarns,
increasing the ratio of polyester will enhance the twist liveliness
of rotor and ring yarns, heat setting can improve the spirality of
the resultant fabrics. This is because polyester has a higher
modulus, and said two types of fiber have different cross sectional
shapes.
[0007] Next, different yarn structures have a different
distribution of stress. Experimental results, such as Barella and
Manich in the Textile Research Journal, Vol. 59, No. 12, 1989, Lord
and Mohamed in the Textile Research Journal, Vol. 44, No. 7, 1974
and Sengupta, and Sreenivasa in the Textile Research Journal, Vol.
64, No 10, 1994 showed that, friction yarns (DREF-II) have the
largest residual torque and trend of deformation in the priority
sequence followed by ring yarns, rotor yarns and air-jet yarns. It
is generally agreed that single ring yarns are composed of a
plurality of uniformly enveloped concentric helical threads, while
fiber migration is a secondary feature. Hence, when the ring yarns
are reverse-twisted, their strength will gradually decreases to
zero, by then the yarns will be all dispersed. In relation to ring
yarns, unconventional spinning systems produce yarns with
core-sheath structures, such as rotor spinning yarn, air jet
spinning yarn and friction spinning yarns. The packing density of
said yarns is uneven and mainly characterized in the partial
entanglement and entrapment of the fibers.
[0008] In addition, many factors can affect the degree of movement
freedom of the loops of the fabric and also the final spirality of
the fabric. Said factors include fabric structure, parameters of
the knitting machine, and the fabric relaxation and fabric setting
due to finishing. All the aforesaid factors affecting the spirality
of fabric were reported in detail by Lau and Tao in the Textile
Asia, Vol. XXVI, No. 8, 1995.
[0009] Same as other materials, the residual torque of the yarns
can be reduced or eliminated with different methods. In the past
several decades, a variety of torque balancing methods have been
developed. According to the basic theory, they can generally be
split into two categories: permanently processing methods and
physical torque balancing methods.
[0010] Permanently setting methods mainly accomplish the purpose of
releasing residual torque by transforming the elastic torsional
deformation into plastic deformation. The method mainly relates to
a variety of setting techniques for material, such as thermal
setting, chemical processing and wet setting etc. In the Textile
Research Journal, Vol. 59, No. 6, 1989, Araujo and Smith have
proved that for air-jet and rotor yarns, the heat setting of single
cotton/polyester blended yarns can effectively reduce the residual
torque of the yarn. However, in relation to natural fibers such as
cotton or wool, permanent setting is too complicated. It may
involve steaming, hot water and chemical processing (such as
mercerization in the case of cotton yarns and treatment with sodium
bisulphite in the case of the wool yarns). In addition, in relation
to natural yarns, setting cannot completely eliminate the residual
torque of the single yarns, and it may also cause damage to the
yarns.
[0011] Compared with permanent processing, physical torque
balancing is a pure mechanical processing technique. The main point
of the method is to fully utilize the structure of yarns to balance
the residual torque generated in different yarns while maintaining
the elastic deformation characteristic of the yarns. Currently in
the industry, separate machines are required to enforce torque
balancing of the yarns hence the cost is higher. The method
comprises plying two identical singles yarns with a twist equal in
number but in the opposite direction to that in the singles yarns;
or feeding two singles yarns with twist of the same magnitude but
in opposite direction onto the same feeder.
[0012] Recently, some new torque balancing methods for yarns also
emerged in the Textile Research Journal, Vol. 65, No. 9, 1995,
Sawhney and Kimmel described a series spinning system for
processing torque-free yarns. The inner core of said yarns is
formed by processing with an airjet system while outside the core
is enwrapped with crust fibers similar to DREF-III yarns. In the
Textile Research Journal, Vol. 62, No. 1, 1992, Sawhey etc. have
suggested a method of processing ring cotton crust/polyester inner
core yarns. Said yarns accomplish balancing condition by utilizing
core yarns with opposite twisting direction from synthetic yarns,
or applying heat processing on the polyester portion of said yarns.
However, it is readily seen that the machines and processing
techniques related to the aforesaid method are generally more
complicated. In the Textile Research Journal, Vol, 57, No. 10,
1997, Tao has processed the layer structure of the inner core-crust
of rotor yarns to generate torque-free single yarns, yet said
technique is not suitable for ring yarns.
[0013] In addition, U.S. Pat. No. 6,860,095 B2, filed by Tao et al.
discloses a method of producing torque-free singles ring yarns.
According to this patent application, a draft fiber is divided into
a plurality of sub-assemblies of fibers. Each sub-assembly of
fibers firstly attains an individual twist value during a false
twisting, and then are twisted together to form the final yarns.
The false twisting is controlled such that balance of the internal
torque of the final yarns is achieved. Furthermore, U.S. Pat. No.
7,096,655 B2 filed by Tao et al. discloses a method and apparatus
for producing a singles ring yarn. In this method, a false twist
device rotates at a first speed for twisting the fibers.
Immediately after the first twisting step, a joint twist of the
second twist in the same direction as the first twist and a third
twist in a reversed direction is supplied to the preliminary yarn
for producing final singles ring yarn. Moreover, a ratio of first
speed to the second speed is controlled for controlling the
residual torque in the final singles ring yarn.
[0014] The aforementioned patents present the method and apparatus
for singles ring yarn. However, the abovementioned patent
application is more appropriate for torque-free singles ring yarn
production in the laboratory scale. The yarn piecing-up and doffing
process can not completely be able to meet the practical
requirements of the largescale production in the textile industry.
Furthermore, the spinning end-breakage when using ordinary cotton
and the cost of investment and maintenance need to be further
reduced for the widely commercial application. In order to overcome
the above shortcomings, two twisting points, instead of one
twisting point, are adopted for the yarn false twisting to obtain
the high false twist efficiency in this invention. In addition, a
ratio of the velocity of the belt to the delivery speed of the yarn
is controlled and the wrapping angle of the yarn on the belts is
adjusted in order to obtain the desired property of the final
singles ring yarn.
OBJECT OF THE INVENTION
[0015] Therefore, it is an objective of the present invention to
provide an improved method and apparatus for producing singles ring
yarns. The method and apparatus has the actual advantages of easy
yarn piecing-up and doffing process, low spinning endbreakage when
using ordinary raw materials and low cost of investment and
maintenance, which not only is able to meet the commercial
requirements of the large-scale production in the textile industry
but also possess high false twist efficiency, wherein instead of
one twisting point, two twisting points are adopted for the yarn
false twisting to improve the false twist efficiency, and wherein
the false twist efficiency is controlled such that the desirable
lower residual torque as well as other yarn properties can be
achieved. Accordingly, a ratio of the velocity of the belt to the
delivery speed of the yarn is controlled and the wrapping angle of
the yarn on the belts is adjusted in order to obtain the desired
property of the final singles ring yarn.
SUMMARY OF THE INVENTION
[0016] According to an aspect of present invention, a method for
producing singles ring yarns is as follows.
[0017] A first high twist is imparted to a strand of traveling
drafted fibers emerged from the front-drafting-roller nip with the
upper belt of a false twist device for producing a preliminary
singles yarn, wherein the belt travels at the velocity of the belt
for twisting the fibers and thus the strength of fiber strand is
enhanced at the spinning triangle when a low twist level is adopted
in the final singles yarn. Immediately after the false twist step
by the upper belt severed as the first twisting point, a joint
twist of a second twist in the same direction as the first twist
and a third twist in the reversed direction are imparted to the
preliminary singles yarn for the production of a final singles ring
yarn, wherein the second twist is produced by a running of the
lower belt on the yarn, wherein the third twist results in
correspondence to the first twist by a running of the upper belt on
the yarn. Immediately after the false twist step by the lower belt
severed as the second twisting point, a joint twist of a forth
twist in the same direction as the second twist, and a fifth twist
in the reversed direction are imparted to the preliminary singles
yarn for the production of a final singles ring yarn, wherein the
forth twist is produced by a rotatable take-up package of the ring
spinning machine onto which the final singles yarn is drawn,
wherein the fifth twist results in correspondence to the second
twist by a running of the lower belt on the yarn. Then the final
singles yarn was drawn onto the take-up package. The upper and
lower belts run in the same velocity.
[0018] Controlling a ratio of the velocity of the belts to the
delivery speed of the yarn and the wrapping angle of the yarn on
the belts can control the false twist efficiency for yarn and thus
the yarn property.
[0019] According to another aspect of present invention, an
apparatus for producing singles ring yarns is as follows.
[0020] The upper belt of a false twist device travelling at the
velocity of the belt imparts a first high twist to a strand of
travelling drafted fibers emerged from the front-drafting roller
nip such that a preliminary singles yarn is produced. The lower
belt of a false twist device travelling at the same velocity as the
upper belt imparts a second twist in the same direction as the
first twist to a preliminary singles yarn emerged from the upper
belt such that a further preliminary singles yarn is produced. A
rotatable take-up package onto which the final singles yarn is
drawn imparts a fourth twist in the same direction as the first
twist and second twist to a preliminary singles yarn emerged from
the lower belt such that final singles yarn is produced, wherein
the double belt travels at the velocity of the belt for twisting
the fibers and thus the strength of fiber strand is enhanced at the
spinning triangle when a low twist level is adopted in the final
singles yarn, wherein a joint twist of a second twist in the same
direction as the first twist and a third twist in the reversed
direction are imparted to the preliminary singles yarn for the
production of a final singles ring yarn, wherein the second twist
is produced by a running of the lower belt on the yarn, wherein the
third twist results in correspondence to the first twist by a
running of the upper belt on the yarn, wherein the yarn was drawn
onto the take-up package at the delivery speed of the yarn, wherein
a joint twist of a forth twist in the same direction as the second
twist and a fifth twist in the reversed direction are imparted to
the preliminary singles yarn for the production of a final singles
ring yarn, wherein the forth twist is produced by a rotatable
take-up package onto which the final singles yarn is drawn, and
wherein the fifth twist results in correspondence to the second
twist by a running of the lower belt on the yarn.
[0021] A ratio of the velocity of the belts to the delivery speed
of the yarn can be controllable and the wrapping angle of the yarn
on the belts is adjustable such that the false twist efficiency and
the yarn property can be adjusted.
[0022] Other aspects and advantages of the invention will become
apparent from the following detailed description, taken in
conjunction with the accompanying drawings, which description
illustrates by way of example the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a side diagrammatic plan view of a spinning
apparatus in accordance with an exemplary embodiment of the present
invention;
[0024] FIG. 2 is a schematic representative in perspective, of a
spinning apparatus in accordance with an exemplary embodiment of
the present invention;
[0025] FIG. 3 is a side enlargement of part of FIG. 1 showing the
geometry interrelations of the yarn, the upper belt and lower
belt;
[0026] FIG. 4 is alternative of a side diagrammatic plan view of a
spinning apparatus in accordance with an exemplary embodiment of
the present invention with a nip false twister consisting of the
two belts;
[0027] FIGS. 5A and 5B are two alternatives of a side diagrammatic
plan view of a spinning apparatus of an exemplary embodiment of the
present invention shown in FIG. 1 with core spandex/filament;
[0028] FIGS. 6A and 6B are two alternatives of a side diagrammatic
plan view of a spinning apparatus of an exemplary embodiment of the
present invention shown in FIG. 4 with core spandex/filament;
[0029] FIG. 7 is an alternative of a side diagrammatic plan view of
a spinning apparatus of an exemplary embodiment of the present
invention with two belts running in cross direction and regulation
block;
[0030] FIG. 8 is another alternative of a side diagrammatic plan
view of a spinning apparatus of an exemplary embodiment of the
present invention with two belts driving individually and running
in cross direction;
[0031] FIG. 9 is another alternative of a top diagrammatic plan
view of a spinning apparatus in accordance with an exemplary
embodiment of the present invention with a nip false twister
consisting of the two belts arranged in concentric circle;
[0032] FIG. 10 illustrates ten alternatives of a cross-sectional
profile of the false twist belt shown in FIGS. 1-9;
[0033] FIG. 11 is a diagrammatic view of the modified curves of
vertical positions relative to time of a ring for yarn doffing.
DETAILED DESCRIPTION
[0034] FIGS. 1 and 2 illustrate a side diagrammatic plan view and a
schematic representative in perspective of a spinning apparatus in
accordance with an exemplary embodiment of the present invention,
respectively. As shown in FIGS. 1 and 2, a roving 101 is delivered
through the drafting system 103, 105 and 107, including a pair of
back drafting rollers 103, a pair of aprons 105, and a pair of
front drafting rollers 107. The drafted roving is twisted by the
upper belt 111 of a false twist device 102 to form a preliminary
singles yarn wherein the false twist for a yarn is provided by the
running action of the upper belt 111. Immediately after the false
twist step by the upper belt 111 severing as the first twisting
point, a joint twist of a second twist in the same direction as the
first twist and a third twist in the reversed direction are
imparted to the preliminary singles yarn 106 for the production of
a final singles ring yarn, wherein the second twist is produced by
a running of the lower belt 113 on the yarn, wherein the third
twist results in correspondence to the first twist by a running of
the upper belt 111 on the yarn.
[0035] Immediately after the false twist step by the lower belt 113
severing as the second twisting point, a joint twist of a forth
twist in the same direction as the first twist and second twist,
and a fifth twist in the reversed direction are imparted to the
preliminary singles yarn for the production of a final singles ring
yarn 104, wherein the forth twist is produced by a rotatable
take-up package 121 onto which the final singles yarn is drawn,
wherein the fifth twist results in correspondence to the second
twist by a running of the lower belt 113 on the yarn. Then the yarn
104 proceeds to a yarn guide 115, and then further to a bobbin 121.
The yarn 104 becomes wound on the bobbin 121 via a traveler 117
moving on a ring rail 119.
[0036] As shown in FIGS. 1 and 2, the double-belts twisting device
102 includes, in addition to other components, primarily an upper
belt 111 and a lower belt 113. In the false twisting device 102,
the upper belt 111 and the lower belt 113 are travelling in
opposite directions with the same velocity. The yarn 109 interacts
with the false twisting device 102 in a slalom-like arrangement
with two false twisting points, i.e., the yarn 109 interacts with
the outer surface on one belt which severs as the first twisting
point, then interacts on the inner surface of the other belt which
severs as the second twisting point. In this case, the yarn 109
interacts with the outer surface of the upper belt 111 first then
diverges to the inner surface of the lower belt 113, before exiting
the false twister. In fact, the yarn is false twisted by the torque
generated by running the double belts in opposite travelling
directions.
[0037] Furthermore, in the exemplary embodiment, there are two
false twisting points of a false twist device by the travelling
upper belt and lower belt for the yarn. The false twist efficiency
for the yarn depends on the friction between the yarn and the
surface of the upper belt and lower belt, and the ratio of the
velocity of the belts to the delivery speed of the yarn. The
residual torque and other yarn properties of the final singles ring
yarn are controlled by controlling the friction between the yarn
and the surface of the upper belt and lower belt, and the ratio of
the velocity of the belts to the delivery speed of the yarn.
[0038] The belt can be driven by a conveyor belt 209 having two or
more pulleys 207, whereby at least one of the pulleys 207 is
attached to a motor 211. The motor 211 is controlled by suitable
electronics such as inverters 213. The motor 211 has the capability
to drive the conveyor belt and further drive the double belts with
a controllable ratio of the velocity of the belts to the delivery
speed of the yarn predetermined by the desired impartation of false
twist and thus the resultant amount of a residual torque as well as
other yarn performance in the final singles ring yarn.
[0039] An additional yarn guide 110 installed above the upper belt
111 for each spindle is used to control the yarn movement during
the spinning. The positioning of the yarn guide 110 should be aware
in the installation. Exceed amount of friction between yarn guide
and yarn results in the yarn breakage where insufficient amount of
false twist results in the poor yarn strength. Several belt guides
203, installed on the both sides of the double belts 111 and 113,
and several pressuring discs 201, installed on upper and below
sides of the belts 111 and 113, are used to control the belts
movement, as well as adjust the geometry interrelations of the yarn
and the upper belt and lower belt and the tension of the belts.
Through the belt guides 203, pressuring discs 201 and the wheels
205, the belts are maintained in a stable condition with
predetermined tension. FIG. 3 is a side enlargement of part of FIG.
1 showing the geometry interrelations of the yarn, the upper belt
111 and lower belt 113; As shown in FIG. 3, ".sub.--.sub.1",
".sub.--.sub.2" and ".sub.--.sub.3" represent the crossing angles
of the straight line (O.sub.1O.sub.2) with respect to the
travelling path of the yarn portions 109, 106 and 104 respectively,
wherein "O.sub.1" is the center of the upper belt and "O.sub.2" is
the center of the lower belt. ".sub.--.sub.1" and ".sub.--.sub.2"
represent the wrapping angles of yarn portions on the upper belt
and lower belt, respectively. "L" represents the length of the
straight line which connects the center (O.sub.1) of the upper belt
and the center (O.sub.2) of the lower belt. The geometry
interrelation of the yarn, the upper belt and lower belt which is
described by the crossing angles (.sub.--.sub.1, .sub.--.sub.2 and
.sub.--.sub.3), wrapping angles (.sub.--.sub.1 and .sub.--.sub.2)
and the length of the straight line (O.sub.1O.sub.2) is important
in determining the optimal adaptation of the double-belts false
twist device to the desired impartation of false twist, and in
optimizing the yarn tension conditions. FIG. 4 is alternative of a
side diagrammatic plan view of a spinning apparatus in accordance
with an exemplary embodiment of the present invention with a nip
false twister 102 consisting of the two belts. As shown in FIG. 4,
the drafted roving is twisted by being contacted from opposite
sides by the travelling upper belt 111 and lower belt 113 of a
false twist device 102 to form a preliminary singles yarn wherein
the false twist for a yarn is provided by the running action of the
upper belt and lower belt 113 travelling in opposite direction.
FIG. 4 provides the false twist device with one twisting point
instead of two twist points shown in FIG. 1. Compared to the one
belt false twisting device, the nip false twister can increase the
pressure between the yarn and the belts.
[0040] FIGS. 5A and 5B are two further embodiments of apparatus of
the present invention as well as method shown in FIG. 1 for the
core spandex/filament yarn. FIG. 5A provides an apparatus of the
present invention for the core spandex/filament singles ring yarn.
The spandex/filament 501 is delivered by feed rollers 503 and
turning rollers 505 and then fed into the front rollers 107. The
draft ratio is controlled by the surface speed ratio of the front
rollers 107 to the feed rollers 503. FIG. 5B provides another
apparatus of the present invention for the core spandex/filament
singles ring yarn. The spandex/filament 501 is also delivered by
feed rollers 503 and turning rollers 505 and then fed into the
drafting system including a pair of back drafting rollers 103, a
pair of aprons 105, and a pair of front drafting rollers 107. The
draft ratio is controlled by the draft ratio of the drafting system
and the surface speed ratio of the back rollers 103 to the feed
rollers 503. Emerging from the front roller nip, the core
spandex/filament and fibers twisted together by running the belts
of the false twist device 102 and then rotating the take-up package
121 to form the final core spandex/filament singles ring yarn
104.
[0041] FIGS. 6A and 6B are other two further embodiments of
apparatus of the present invention as well as method shown in FIG.
4 for the core spandex/filament yarn. FIG. 6A provides an apparatus
of the present invention for the core spandex/filament singles ring
yarn. The spandex/filament 501 is delivered by feed rollers 503 and
turning rollers 505 and then fed into the front rollers 107. The
draft ratio is controlled by the surface speed ratio of the front
rollers 107 to the feed rollers 503. FIG. 6B provides another
apparatus of the present invention for the core spandex/filament
singles ring yarn. The spandex/filament 501 is also delivered by
feed rollers 503 and turning rollers 505 and then fed into the
drafting system including a pair of back drafting rollers 103, a
pair of aprons 105, and a pair of front drafting rollers 107. The
draft ratio is controlled by the draft ratio of the drafting system
and the surface speed ratio of the back rollers 103 to the feed
rollers 503. Emerging from the front roller nip, the core
spandex/filament and fibers twisted together by running the belts
of the false twist device 102 and then rotating the take-up package
121 to form the final core spandex/filament singles ring yarn
104.
[0042] FIG. 7 is another embodiment of apparatus of the present
invention as well as method with double belts running in cross
direction and regulation block for the friction adjusting between
the yarn and belts. As shown in FIG. 7, the outer face of the outer
belt 701 is disposed in an opposing, substantially non-contacting
relationship with the outer face of the inner belt 703, and defines
a gap there between. A yarn 109 is advanced along the line which
bisects the angle formed by the two crossing belts, and through the
twisting zone composed of the opposing belts 701 and 703
overlapped. The belts are pressed against the yarn in the area of
the twisting zone by the regulation block 705 which consists of
spring and shim assembly. The regulation block can adjust the
friction between the yarn and belts, improve the control of fiber
movement during the false twisting of the yarn, provide an easier
yarn piecing process as well as increase the false twist
efficiency.
[0043] FIG. 8 is another alternative of a side diagrammatic plan
view of a spinning apparatus of an exemplary embodiment of the
present invention with two belts driven individually and running in
cross direction; As shown in FIG. 8, the outer face of the outer
belt 801 is disposed in an opposing, substantially non-contacting
relationship with the outer face of the inner belt 803, and defines
two gaps there between. A yarn 109 is advanced along the line which
bisects the angle formed by the two crossing belts, and through the
twisting zone composed of the opposing belts 801 and 803
overlapped. FIG. 8 provides the false twist device with two
twisting point instead of one twist points shown in FIG. 7.
Compared to the false twist device shown in FIG. 7, the false twist
device shown in FIG. 8 can adjust the contact area between the yarn
and belts to further improve the control of fiber movement during
the false twisting of the yarn, increase the false twist efficiency
as well as provide an much easier yarn piecing process.
[0044] FIG. 9 is another alternative of a top diagrammatic plan
view of a spinning apparatus in accordance with an exemplary
embodiment of the present invention with a nip false twister
consisting of the two belts arranged in concentric circle. As shown
in FIG. 9, the yarn 109 is false twisted by the running action of
outer belt 901 and inner belt 903 travelling in opposite direction
in a false twist device to form a preliminary singles yarn. The
outer belt 901 and inner belt 903 can be driven individually in
high velocity as well as in more stable running condition to
increase the false twist efficiency. FIG. 10 illustrates ten
alternatives of a cross-sectional profile of the false twist belt
shown in FIGS. 1-9. The belt profile particularly the shape of the
contacting section of the belt with the yarn, the hardness as well
as the surface property of the belt are important for false
twisting effects. The round shape and elliptical shape illustrated
by the cross-sectional profiles 1001 and 1003 for the belt are two
desirable contacting shapes with the yarn during the yarn false
twisting. The cross-sectional profile 1001' and 1003' for the belt
are another two alternatives with hollow inside the belt which
results in the reduction of hardness of the belt and thus changes
the friction between the yarn and the belt. All these four types of
belt shapes can be used for the yarn false twisting process showed
in FIGS. 1-6, and which one is to be used mainly depends on the
required false twisting effects. The cross-sectional profiles 1005,
1007 and 1009 are the other three shapes for the belt and the
cross-sectional profiles 1005', 1007' and 1009' are their
corresponding three alternatives with hollow inside the belt,
wherein the top shape is for the contacting area of the belt with
the yarn. All these six types of belt shapes can be used for the
yarn false twisting process showed in FIGS. 7-9. FIG. 11 is a
diagrammatic view of the modified curves of vertical positions
relative to time of a ring for yarn doffing. The modifications have
been proposed on the conventional doffing process to avoid yarn
snap during doffing process. In FIG. 11, 1101 and 1103 are
respectively the modified curves of the mean vertical position and
the resultant vertical position of the ring rail. Two axes of the
coordinates represent time 1105 and vertical position 1107,
respectively. According to an exemplary embodiment of the present
invention, the spinning apparatus is powered off at time 1109 which
should be matched to the power off time of the motor 211 when the
ring rail moves upwards to the up-most position. Thereafter, the
ring rail is waited for a predetermined period of time 1111. Then
it is finally pulled down the ring gradually at the winding time
1115 until the ring completely stops at the termination time 1117,
wherein 1113 indicates the total stop period of time.
* * * * *