Method and apparatus for fasciated yarn spinning

A method and apparatus for spinning a modified fasciated yarn at a high production rate featuring a combination of open-end spinning and fasciated yarn spinning. A sliver is opened by a combing roller and deposited as a fiber layer on a fiber collecting surface of a drum rotor rotating at a high speed. Thereafter, the fiber layer is drawn off from the fiber collecting surface as a continuous fiber bundle by a central rotor rotating coaxially with the drum rotor at a faster speed. During the drawing-off operation, the fiber bundle is flattened to a ribbon form by making contact to a deflector and is subjected to a vortex within an air twisting nozzle mounted on the central rotor to form a resultant yarn. According to the present invention, high production rate can be obtained because a roller drafting system having aprons can be omitted.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a method and an apparatus for producing a 
fasciated yarn with a specific structure, a core portion of which has a 
true twist of the same direction as that of surface fibers entangling 
around the core portion, and for producing a two-folded yarn consisting of 
the above-mentioned yarns in one process. 
2. Description of the Prior Art 
Fasciated yarn spinning is a process in which a ribbon-like fiber bundle is 
continuously introduced into an air twisting nozzle and false-twisted by a 
vortex generated within a yarn passage in the air twisting nozzle, thereby 
causing edge portion fibers of the fiber bundle to entangle with a core 
portion thereof to form a yarn having a mechanical strength sufficient for 
practical use, though the core portion is of a substantially twistless 
structure. 
The mechanism for forming the fasciated yarn is as follows. The ribbon-like 
fiber bundle has a plurality of "free end fibers" in its edge portion. 
"Free end fiber" means a fiber with one end embedded in the core portion 
of the fiber bundle and the other end free from constraint from any other 
fibers. When the fiber bundle is subjected to the vortex, both the core 
portion and the free end fibers are rotated. The free ends remain straight 
in the early period of the twisting operation, therefore are finally wound 
onto the core portion with less number of twists than that of the core 
portion itself. During the untwisting operation after the twisting 
operation, the core portion of the fiber bundle is completely untwisted to 
its original state, i.e., zero twist. However, the free end fibers are 
overly untwisted past the zero twist point to an extent corresponding to 
the difference between the twist numbers of the core portion and the free 
end fibers at the end of the prior twisting operation and entangle around 
the twistless core portion to form a fasciated yarn. 
Such fasciated yarn can be produced at a high rate by utilization of an air 
twising nozzle generating a high rotational speed vortex. 
However, a conventional roller drafting system utilized for preparing the 
fiber bundle cannot endure a speed of processing as high as that of the 
above-mentioned fasciated yarn spinning, because the aprons in the 
drafting system would be easily damaged in a short time period. 
In an entirely different area, there has been prevailed open-end spinning. 
In open-end spinning, a fiber opened from a sliver is fed onto a 
collecting surface of a rotating drum rotor to form fiber layers by the 
action of centrifugal force exerting on the open fibers. The fiber layers 
are then continuously drawn off from the collecting surface as a fiber 
bundle while being imparted with a true twist due to the rotation of the 
drum rotor during the drawing-off operation. 
In open-end spinning, since the roller drafting system can be omitted, the 
afore-said problem is diminished. Moreover, this spinning system had also 
an advantages of high rate production due to light weight of the drum 
rotor. However, open-end spinning is not suitable for producing a thinner 
yarn because the yarn may break by excessive tension caused by the 
centrifugal force. 
SUMMARY OF THE INVENTION 
Accordingly, it is an object of the present invention to provide a method 
and an apparatus for fasciated yarn spinning with a high production rate. 
It is another object of the present invention to provide a method and an 
apparatus for fasciated yarn spinning utilizing a drum rotor for 
collecting individually opened fibers to form a fiber bundle and at least 
an air twisting nozzle for false-twisting the fiber bundle with a vortex 
to form a fasciated yarn. 
It is a further object of the present invention to provide a method and an 
appratus for producing a fasciated yarn having a true-twisted structure 
throughout its length. It is a still further object of the present 
invention to provide a method and an apparatus for producing in one 
process a folded yarn composed of two fasciated yarns.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In FIG. 1, at a top of a housing 1 is formed a stationary supporting wall 2 
in a cylindrical shape with a center axis O--O. A drum rotor 3 is 
rotatably supported coaxially to the center axis O--O inside of the 
supporting wall 2 by means of bearings 5 and 5, mounted on a circumference 
4 of the drum rotor 3, and is driven by a drive shaft (not shown) through 
a belt 6 engaged with the circumference 4. 
On an inner wall of the drum rotor 3 is provided a recessed fiber 
collecting surface 7 of an annular shape, the cross-section of which is 
semi-circular and the rotational axis of which corresponds to the center 
axis O--O of the supporting wall 2. 
Within the space inside the housing 1 and surrounded by the supporting wall 
2 is provided a support member 8, a part of which confronts the fiber 
collecting surface 7 of the drum rotor 3 at a certain distance therefrom. 
An open cut 9 is formed beneath the support member 8 and a fiber channel 
10 is provided from a wall of the open cut 9 to the fiber collecting 
surface 7. The fiber channel 10 may be open to the atmosphere or may be 
connected to a high-pressure air source, such as a fan, if necessary 
A combing roller 12 is rotatably mounted in a recess 11 and is forcibly 
driven in the direction shown by the arrow. A sliver 100 is fed to the 
combing roller 11 by means of a feed roller 13, also mounted in the recess 
11, and a presser 15, urged onto the feed roller 13 by a spring 14, and is 
opened with saw teeth 16 projected on a periphery of the combing roller 12 
into individual fibers 101. The opened fibers 101 are transferred to the 
fiber collecting surface 7 of the drum rotor 3 through the fiber channel 
10 along with an air stream. 
A step-wise hole 18 is formed coaxially with the axis O--O at a center 
portion of the support member 8 of the housing 1. A center shaft 20 of a 
central rotor 19 is inserted into the hole 18 and rotatably supported with 
bearings 21 and 21. The lower end of the center shaft 20 protrudes into 
the open cut 9 to form a pulley 22. The central rotor 19 is rotated by a 
drive shaft (not shown) through a belt 23 engaged with the pulley 22 in 
the same directions as the drum rotor 3 at a higher rotational speed N+n 
relative to the rotational speed N of the drum rotor 3. 
An arm 24 extends radially from an upper end of the center shaft 20. At the 
outer end of the arm 24 is mounted a hollow cylindrical guiding member 25, 
on an inner wall of which is provided a recessed air chamber 26 of an 
annular shape. Inside of the guiding member 25 is tightly inserted an air 
twisting nozzle 29 having a yarn passage 27 and a plurality of jets 28, 
whereby the air chamber 26 can communicate with the jets 28. The yarn 
passage 27 directs onto the fiber collecting surface 7 and inclines 
relative to the axis O--O so that an axis P--P thereof becomes further 
from the axis O--O as the yarn passage 27 goes downward. 
The jets 28 are circumferentially equidistantly bored in a wall of the 
nozzle 29 and open on an inner wall of the yarn passage 28 with such an 
inclination that an image of the jets 28 projected onto a plane including 
the axis P--P of the yarn passage 27 intersects the axis P--P with a 
certain acute angle, for example 45.degree., and that the jets 28 deviate 
from the axis P--P with a certain distance, whereby a vortex occurs within 
the yarn passage 27 along and around the axis P--P. 
An inlet opening 30 of the nozzle 29 is of a conical shape and connected to 
the yarn passage 27 through an orifice 31 having a smaller diameter than 
that of the yarn passage 27. Accordingly, a suction stream can be formed 
from the inlet opening 30 to the yarn passage 27 when high pressure air in 
the air chamber 26 is ejected from the jets 28 into the yarn passage 27. 
On the top housing 1, a plate 33 having a central opening 32 to permit 
rotation of the guiding means 19 is mounted. A lid 36 having an interior 
space 34 to permit rotation of the guiding means 19 and an outlet opening 
35 at a top wall thereof is mounted onto the plate 33. Both the plate 33 
and the lid 36 are rigidly secured to the housing 1 with bolts 37 and 37. 
A deflector 40 protrudes annularly on an inner wall of the opening 32 of 
the plate 33 about the axis O--O. A cross-section of the deflector 40 
along a plane including the axis O--O is substantially of a circular shape 
encircled with an arcuate surface 41, except for a root portion connected 
to the plate 33. The deflector 40 is disposed between an imaginary plane 
of rotational traces of the inlet opening 30 and the inner wall of the 
drum rotor 3 with suitable clearance, in other words, in a close, but 
non-contact relationship. Further, the portion of the arcuate surface 41 
furthest from the root position is in the vicinity of the axis P--P of the 
yarn passage 27, preferably tangential to the axis P--P or intersecting 
thereto. Particularly, in FIG. 2, there is shown the deflector 40 having 
the arcuate surface 41 tangential to the axis P--P. 
An annular groove 45 is provided on a circumference of the center shaft 20 
about the axis O--O and on the inner wall of the stepwise hole 18 in which 
the center shaft 20 is supported. An annular air reserver 46 is provided 
surrounding the groove 45. The groove 45 and the air chamber 26 
communicate to each other through ducts 47 and 48 respectively bored in 
the center shaft 20 radially and axially and another duct 49 in the arm 24 
(refer to FIG. 3). On the other hand, the air reserver 46 is connected to 
a high-pressure air source (not shown) through a duct 50. 
Through the above-mentioned duct system, high-pressure air is fed from the 
air source to the air chamber 26 and is ejected from the jets 28 to cause 
a vortex within the yarn passage 27. A plurality of suction holes 51 are 
opened on the fiber collecting surface 7 of the drum rotor 3. The suction 
holes 51 communicate through an annular channel 52 to a suction duct 53 
opening on the upper surface of the drum rotor 3. The duct 53 is connected 
to a subatmospheric air source (not shown) through an annular channel 54 
formed on the lower surface of the plate 33 at a position corresponding to 
the duct 53. Therefore, the collecting surface 7 of the drum rotor 3 can 
be subjected to a negative pressure. Reference numerals 55 designate air 
sealing means for preventing air leakage. 
Additionally, as shown in FIG. 1, a yarn guide 56, a draw-off roller 57, 
and a winding drum 58 are arranged for taking up the resultant yarn as 
usually utilized in the conventional apparatus. 
The operation of the above-mentioned apparatus according to the present 
invention will now be explained. 
A sliver 100 is supplied by the feed roller 13 and the presser 15 to the 
combing roller 12, then is opened to individual fibers 101 by means of the 
saw teeth 16 of the combing roller 12, which rotates in the arrow 
direction. The fibers 101 are transported to the fiber collecting surface 
7 of the drum rotor 3, which is rotating at a high speed, through the 
fiber channel 10 along with an air stream supplied thereto. 
Since the fiber collecting surface 7 is concaved in an arcuate shape 
cross-section, the air stream turns in its travelling direction along the 
curvature of the collecting surface 7 to deposit the fibers 101 evenly on 
the fiber collecting surface 7 to form a fiber layer 102. The fiber layer 
102 is held thereon by centrifugal force as well as the sucking effect 
from the suction holes 51. 
After the fiber layer 102 is formed on the fiber collecting surface 7, a 
pilot yarn is inserted into the drum rotor 3 through the yarn passage 27 
and is engaged with the fiber layer 102. The engaged end of the pilot yarn 
is entangled with the fiber layer 102 and peels the fiber layer 102 from 
the fiber collecting surface 7 continuously to form a fiber bundle 103. 
The fiber bundle 103 is drawn out from the drum rotor 3 by the draw-off 
roller 57 through the yarn passage 27 and is wound onto the package 59. 
Thus the spinning operation is carried out continuously. 
During the above-mentioned drawing-off operation, the fiber bundle 103 is 
false-twisted within the yarn passage 27 to form a fasciated yarn, while, 
at the same time, being true-twisted between the deflectors 40 and the 
draw-off roller 57 due to rotation of the central rotor 19 including the 
air twisting nozzle 29. 
As shown in FIG. 2, the fiber bundle 103 introduced into the inlet opening 
30 and the orifice 31 of the air twisting nozzle 29 is subjected to a 
suction stream caused by an air stream ejected from the jets 28 and, 
thereby, is subjected to a dragging force T directed toward the yarn 
passage 27. The fiber bundle 103 is pressed onto the arcuate surface 41 of 
the deflector 40 with a resultant force t expressed by the following 
equation: 
EQU t=T.multidot.(sin.alpha./2), 
where .alpha. is an angle between the axis P--P which corresponds to the 
direction of the force T and a line connecting points A and B where the 
fiber layer 102 is peeled from the fiber collecting surface 7 where the 
fiber bundle 102 contacts the arcuate surface 41, respectively. Due to the 
force t, the fiber bundle 103 is flattened and widened to a maximum width 
in the traveling passage from the aforesaid point A to a point C where the 
fiber bundle 103 is peeled from the arcuate surface 41. 
FIG. 4 illustrates transformations of the fibers 101 to the fiber layer 102 
and the ribbon-like fiber bundle 103, each of which corresponds to a stage 
of the air duct 10, the fiber collecting surface 7, or the deflector 40, 
respectively. This flattening of the fiber bundle is very useful for 
producing a well-fasciated yarn. 
The air stream ejected from the jets 28 into the yarn passage 27 causes a 
vortex able to impart the same directional twist to the fiber bundle 103 
as the true twist given by rotation of the drum rotor 3. The rotational 
direction of the vortex is not, however, limited to the above one, but may 
be reversed under certain spinning conditions such as the rotational speed 
of the drum rotor, pressure of the ejected air, and drawing-off speed of 
the yarn. 
The fiber bundle 103 which has been widened by contact with the deflector 
40 is guided into the yarn passage 27 and twisted by the vortex in the 
upstream region. The twist imparted to the fiber bundle becomes larger at 
the core portion of the fiber bundle and smaller at the edge portion 
thereof, as described hereinbefore. The twist given to the fiber bundle in 
the upstream region is untwisted in the downstream region due to the 
"false-twisting" effect. Finally, the edge portion fibers entangle around 
the twistless core portion with a twist of a direction reverse to the 
false-twist and of a number corresponding to the twist difference of the 
core portion and the edge portion in the false-twisting zone. At the same 
time, the aforesaid portion of fiber bundle 103 is true-twisted due to the 
rotation of the drum rotor 3. Accordingly, the resultant yarn has a 
structure in which a conventional fasciated yarn with a twistless core 
portion is additionally twisted in the direction so as to strengthen the 
fasciated effect. 
As the rotational speed N of the drum rotor 3 increases, the evenness of 
the fiber layer 102 deposited on the fiber collecting surface improves 
because of the doubling effect. However, a high rotational speed of the 
drum rotor 3 results in a high centrifugal force which requires a large 
tension for drawing off the resultant yarn from the fiber collecting 
surface and may cause yarn breakage in the case of spinning of thinner 
yarns. Therefore, the rotational speed N should be selected in 
consideration of a balance of the above-mentioned facts. 
According to the experience of the present inventors, the minimum 
rotational speed of a drum rotor 3 with a 100 mm inner diameter is 
approximately 1000 rpm. On the other hand, the central rotor 19 should 
rotate at a speed where the fiber layer 102 peels off from the fiber 
collecting surface 7 by an amount corresponding to the yarn drawing-off 
speed. In the above case, if the yarn drawing-off speed is 200 m/min, the 
rotational speed of the central rotor 19 is preferably 1000+636=1636 rpm. 
One set of preferable spinning conditions is as follows: 
Rotational speed of drum rotor: 5000 rpm 
Rotational speed of central rotor: 6000 rpm 
Yarn drawing-off speed 314 m/min 
Further, a distance l between the peeling point A of the fiber bundle 103 
from the drum rotor 3 and the contact point B of the fiber bundle 103 to 
the deflector 7 should be selected equal to a mean length of staple fibers 
composing the sliver 100 for securing stable spinning. 
A second embodiment according to the present invention is illustrated in 
FIG. 5. The same reference numerals are utilized for designating parts of 
the second embodiment the same as those of the first embodiments shown in 
FIG. 1. An explanation of those parts is omitted. 
In the second embodiment, another arm 124 extends radially from the upper 
end of the center shaft 20 toward the opposite direction of the arm 24 
relative to the axis O--O. At the outer end of the arm 124 is mounted a 
hollow cylindrical guiding member 125. On the other wall of the guiding 
member 125 is provided an annular recess to form an air chamber 126. An 
air twisting nozzle 129 having a yarn passage 127 and jets 128 is rigidly 
inserted into the guiding member 125, so that the air chamber 126 
communicates with the jets 128. Air from the high-pressure air source (not 
shown) is ejected from the jets 128 into the yarn passage 127 to cause a 
vortex through a duct 149 bored in the arm 124 and connected to the duct 
48 in the center shaft 20. The above-said air twisting nozzle 129 has the 
same size and inclination as the nozzle 29. 
In the second embodiment, another recess 111 is provided symmetrically to 
the recess 11 about the axis O--O. A combing roller 112, a feed roller 113 
and a presser 115 urged onto the feed roller 113 by means of a spring 114 
are arranged therein. Individual fibers 101 opened and separated by saw 
teeth 116 provided on the periphery of the combing roller 112 are 
transported to separate sections of the fiber collecting surface 7 of the 
drum rotor 3 through a fiber channel 110. 
According to the second embodiment, the fibers 101, 101' supplied from two 
combing rollers 12, 112 arranged symmetrically to each other about the 
axis O--O are received onto separate sections of the fiber collecting 
surface 7 of the drum rotor 3 and are withdrawn separately from the drum 
rotor 3 to form the fiber bundles 103, 103', respectively. The fiber 
bundles 103, 103' are fasciated by means of the air twisting nozzles 29 
and 129, respectively, during the above withdrawing operation and are 
simultaneously imparted with a true twist throughout the length thereof by 
the rotation of the drum rotor 3 to form two resultant yarns 104, 104'. 
Thereafter, the resultant yarns 104, 104' may be taken up by a yarn guide 
and winding drum to form two packages of the single yarn 104, 104' or may 
be plied together and taken up onto a package of a two-folded yarn 105 as 
shown in FIG. 5. In the former case, the productivity of the apparatus can 
be doubled compared to the one shown in FIG. 1. In the latter case, the 
two-folded yarn can be obtained in one process. 
According to the present invention, since a fiber bundle is continuously 
formed from a fiber layer deposited on a fiber collecting surface of the 
drum rotor without utilizing a roller drafting system, high processing 
speed can be attained compared to a conventional fasciated spinning system 
while maintaining good evenness of the resultant yarn. 
Since the fiber bundle is flattened immediately after being peeled off from 
the fiber collecting surface to form a fiber ribbon by means of a 
deflector with the air of centrifugal force and a dragging force of 
suction air, a plurality of free end fibers are formed in the edge 
portion, thereby a well-fasciated yarn can be obtained. Further, since an 
additional twist is imparted to an intermediate yarn drawn out from the 
air twisting nozzle due to rotation of the drum rotor, a resultant yarn 
with a good mechanical strength can be formed. 
According to the second embodiment of the present invention, since two sets 
of combing rollers and air twisting nozzles are installed ln one 
apparatus, two single yarns are spun simultaneously from one drum rotor, 
or a folded yarn is obtained in one process.