Title of Invention

METHOD & DEVICE FOR PRODUCING AN AUTOMATICALLY TWISTED YARN

Abstract Method for production of a self-twist yarn (1) wherein firstly at least two rovings (2,3) are run through at least one false twisting device (4), through which the rovings (2,3) are each given periodically alternating areas with S and Z twisting which are separated from one another by areas with no twisting (0), and the rovings (2,3) are then brought together so that they spin together automatically due to their self-twist characteristics, the areas with no twisting (0) in the spun self-twist yarn (1) exhibiting a difference in phase ( ), characterized in that to produce the difference in phase ( ) at least one of the rovings (2), after running through the false twisting device (4), is guided over at least one deflecting pulley (5) to a guiding pulley (6) and the rovings (2,3) are brought together on the guiding surface (6a) of the guiding pulley (6).
Full Text Translation

The invention relates to a method and a device for production of a self-twist yarn
Such methods and devices are known from the state of the art, for example according to the British patent specification GB 1 144 614. German patent specification DE 26 37 208 and US patent specification 4,279,120. Here, by means of so-called false twisting devices, two or more rovings are provided alternately with areas of S and Z twists which are separated from one another by areas with no twisting or with minimal twisting. T wo rovings twisted in this way are then brought together so that the two yarns automatically twist together due to their reverse twisting tendency to form a so-called self-twist yarn, the areas of the two rovings with no twisting or with minimal twisting being advantageously displaced in phase.
Furthermore, a generic device for production of such a self-twist yarn from Platt UK Limited is known from the state of the art (for example refer to the service manual for the "Self-twist spinner, type 888" of Platt UK Limited, Blackburn, England). In this device the two yarns are brought together by means of uniting eyes. Here, in order to produce a specific difference in phase between the areas of the two yarns with no twisting, one of the two rovings, after running through the false twisting device, is first guided through a deflecting eye and then deflected to the uniting eye in which it is brought together with the other roving.
Deflecting one roving through the deflecting eye has proved to be advantageous since then any desired difference in phase can be set between the areas with no twisting or with minimal twisting between the two rovings. Here, it has been found that the strength of the resulting self-twist yarn depends a great deal on the phase displacement of the areas with no twisting. To obtain a high yarn strength, a preferred difference in phase of 30o is indicated in the named manual from Platt.

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However, with the known devices breakages of roving threads occur frequently since these are subject to severe wear due to the friction on the deflecting and uniting eyes. This wear also reduces the strength of the spun self-twist yarn.
Therefore, the object is to provide a method and a device for production of a self-twist yarn which produces the highest possible strength of self-twist yarn. This object is achieved to produce the difference in phase ( ) at least one of the rovings (2), after running through the false twisting device (4), Is guided over at least one deflecting pulley (5) to a guiding pulley (6) and the rovings (2, 3) are brought together on the guiding surface (6a) of the guiding pulley (6) wherein the guiding pulley (6) and the or each deflecting pulley (S) are mounted rotatably, their axes of rotation standing perpendicular to the plane which is defined by the two rovings (2, 3), and the guiding pulley (6) being arranged in the yarn running direction (C) after the or each deflecting pulley (5).
The invention is explained in greater detail in the following on the basis of embodiment examples with reference to the accompanying drawings in which:
Figure 1 shows a diagrammatic illustration of a device for production of a self-test
yarn;
Figure 2 shows a diagrammatic illustration of a false twisting device for
production of a roving with periodically alternating areas with S and Z twisting;
Figure 3A shows an illustration of two rovings from figure 2 and of a self-twist
yarn produced from these rovings by bringing them together without any
difference in phase;
Figure 3B shows an illustration of two rovings from figure 2 and of a self-twist
yarn produced from these rovings by bringing them together with a difference in
phase between the untwisted areas;
Figure 4 shows a plan view of a device for production of a self-twist yarn;
Figure 5 shows a side view of the device from figure 4;

3 figure 6 shows an advantageous embodiment of a device according to figure 4.
Figure 1 shows diagrammatically a device for production of a self-twist yarn. This device essentially comprises a drawing device 11 for production of two untwisted rovings 2 and 3. a false twisting device 4 through which the rovings 2 and 3 are given periodically alternating areas with S and Z twisting, and a twisting device 12 in which the two twisted rovings 2. 3 are brought together so that they twist to form a self-twist yarn 1.
In the embodiment example of figure 1, the drawing device 11 is embodied as a roller drawing device with two drawing rollers 13, 14. The false twisting device 4 is a rubbing device known per se. This exhibits two essentially cylindrical axially parallel rubbing rollers 7, 8 rotating about their axes. Here, the rubbing rollers 7, 8 rotate in opposite directions to one another and so convey the roving 2, 3 nipped between them. Apart from their rotation, the two rubbing rollers 7, 8 oscillate in the axial direction between two limit positions. Through this axial oscillation the two rovings 2. 3 passing through are twisted and thus receive a twist. In one direction of oscillation the rovings receive S twisting, in the opposite direction of oscillation Z twisting. Since the rubbing rollers 7, 8 are stationary at the reversing points of their axial movement, the rovings receive no twisting at these points. Therefore, the alternating areas with S and Z twisting are separated by areas with no twisting or areas with minimal twisting.
As an alternative to the false twisting device 4 with rubbing roller 7, 8 shown in figure 1, false twisting devices of the clamping type, as described for example in DE 198 27 870, or false twisting devices which impart twisting to the rovings by air turbulence (such as described for example in US 4,279,120), can be used.
After running through the false twisting device 4, one of the two rovings 2 is guided over a deflecting pulley 5 to a guiding pulley 6. The other roving 3, after running through the false twisting device 4, is passed directly to the guiding pulley 6 where the rovings 2, 3 are brought together at the uniting point 13.

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When the two rovings 2, 3 are brought together, it has been found that the phase position of the areas of the two rovings 2. 3 with no twisting has a major influence on the strength of the spun self-twist varn 1 Figure 3A shows a self-twist yarn produced by spinning together two rovings 2, 3, the rovings 2, 3 being brought together so that the areas with no twisting lie directly opposite one another and are therefore in phase. Thus, the areas with no twisting always lie in the same place in the spun self-twist yarn 1. Since the rovings in the areas with no twisting exhibit reduced strength, the self-twist yarn also exhibits reduced strength in these locations.
For this reason it is advantageous to bring the two rovings 2, 3 together so that the areas with no twisting are not in alignment, as shown in figure 3B. There the areas with no twisting exhibit a phase difference of The phase difference can be a fraction of the period of the alternating areas with S and Z twisting, a 360° period being defined by the difference L between two areas with twisting in the same direction. In figure 3B the phase difference is approximately 90°.
Comparison tests have shown that the highest yarn strength is obtained when the phase difference lies between 90° and 135°.
In order to set the desired phase difference between the untwisted areas, according to figure 1 one of the two rovings 2 is guided over a deflecting pulley 5 to the guiding pulley 6. The guidance over the deflecting pulley 5 means that the roving 2 between the false twisting device 4 and the uniting point 13 covers a longer distance than the roving 3 which after running through the false twisting device 4 is guided directly to the guiding pulley 6. The longer distance covered by the roving 2 compared with the roving 3 determines the phase difference between the untwisted areas.
The design and the arrangement of the pulleys 5 and 6 is illustrated in greater detail in figures 4 and 5. In the embodiment example shown there, the two pulleys 5 and 6 are mounted rotatably, and in each case their axis of rotation is perpendicular to the plane which is defined

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by the two rovings 2 and 3. In the embodiment example in figure 4, the deflecting pulley 5 is further from the false twisting device 4 than the guiding pulley 6. After running through the false twisting device 4, the roving 2 is initially guided over the deflecting pulley 5 and then passed to the guiding pulley 6.
As can be seen in figures 4 and 5, the pulleys 5 and 6 are embodied as disc-shaped cylinders, with a guiding notch 14 formed in the cylinder surface for improved guidance of the rovings 2, 3. The guiding notch 14 prevents the rovings 2, 3 slipping sideways from the guiding surfaces 5a, 6a of the pulleys 5,6.
The two rovings 2 and 3 are brought together at the uniting point 13 on the guiding surface 6a of the guiding pulley 6.
The additional distance covered by the roving 2 between the false twisting device 4 and the uniting point 13 compared with the other roving 3 can be set through the distance between the axes of rotation 5b and 6b of the pulleys 5 and 6. For this, the pulleys 5 and 6 are mounted so that their axes of rotation 5b and 6b are displaceable in relation to one another in the plane defined by the two rovings 2 and 3.
Comparison tests with pulleys of different sizes have shown that the highest yarn strength is to be obtained with pulleys whose diameter is at least 10% of the length L of the period of the alternating areas with the S and Z twisting of the spun self-twist yarn 1.
With regard to the yarn strength of the self-twist yarn 1 produced, it has also proved to be particularly advantageous if the two rovings 2, 3 run essentially parallel to one another in the area of the false twisting device 4 and in the area before guidance over the deflecting pulley 5, and the roving 3, which is not guided over the deflecting pulley 5, runs in the same direction as the spun self-twist yarn 1 in the area between the false twisting device 4 and the uniting point 13. This routing of the rovings 2 and 3 prior to their being brought together allows twisting without the rovings coming under stress or being able to catch on the guiding pulley

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6. This produces a uniform spacing between the untwisted zones of the rovings 2 and 3 in the spun self-twist yarn I.
As shown in the embodiment example in figure 6, the spun self-twist yarn I can be guided in the yarn running direction after the uniting point 13 over a rotatably mounted pressure pulley 10 This allows clean and stress-free guidance of the spun self-twist yarn 1. In addition, the roving 3, which is not deflected over the deflecting pulley 5, can be guided in the yarn running direction C before the uniting point 13 over a pressure pulley 9 to the guiding surface 6a of the guiding pulley 6. This guarantees precise and stress-free guidance of the roving 3 to the guiding surface 6a. Stress-free uniting of the rovings 2 and 3 helps considerably to improving the yarn strength of the self-twist yam 1 and also produces constant spacing of the untwisted zones over the length of the self-twist yarn 1. This again improves the properties of fabrics woven with such self-twist yarns 1 as regards their strength and their visual appearance
Compared with the deflecting and uniting devices known from the state of the art and embodied as deflecting eyes and uniting eyes, the present invention has the advantage that the rovings cannot be worn or damaged by the deflecting and uniting operations. With eyes, the rovings 2, 3 are worn due to the friction of the yarns on the eyes before they are brought together to form the self-twist yarn 1. In addition, the rovings 2, 3 can catch in the eyes, which frequently leads to thread breakages during the production process. This leads to frequent and undesired interruptions in the production process. Furthermore, catching of the rovings 2, 3 in the eyes can lead to unevenness in the spacing of the untwisted zones in the self-twist yarn 1 This has an adverse effect on the appearance of fabrics woven with such self-twist yarns
According to the invention, these disadvantages of the state of the an are overcome in that after running through the false twisting device 4, the rovings 2 and 3 are guided over a deflecting pulley 5 and a guiding pulley 6 instead of eyes and then brought together Here, the two rovings 2, 3 are brought together on the guiding surface 6a of the guiding pulley 6, which ensures that the rovings 2 and 3 are brought together cleanly and free of stress Here, the two rovings 2 and 3 cannot catch in the uniting device when they are brought together.

With the method according to the invention and the device according to the invention self-twist yarns can be produced exhibiting a tensile strength up to 60% higher than those produced conventionally.

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We Claim;
1. Method for production of a self-twist yarn (1) wherein firstly at
least two rovings (2,3) are run through at least one false twisting
device (4), through which the rovings (2,3) are each given
periodically alternating areas with S and Z twisting which are
separated from one another by areas with no twisting (0), and the
rovings (2,3) are then brought together so that they spin together
automatically due to their self-twist characteristics, the areas with
no twisting (0) in the spun self-twist yarn (1) exhibiting a
difference in phase ( ), characterized in that to produce the
difference in phase ( ) at least one of the rovings (2), after running
through the false twisting device (4), is guided over at least one
deflecting pulley (5) to a guiding pulley (6) and the rovings (2,3)
are brought together on the guiding surface (6a) of the guiding
pulley (6).
2. Method as claimed in claim 1, wherein the difference in phase ( )
lies between 90° and 135o.
3. Method as claimed in one of claims 1 and 2, wherein the two
rovings(2,3) run essentially parallel to one another in the area of
the false twisting device (4) and before the guidance over the
deflecting pulley (5), one roving (2) is guided, changing the
original running direction (C), over a deflecting pulley (5) to the guiding pulley (6), and the other roving (3) is guided, without changing the original running direction (C), for uniting of the rovings (2,3) to the guiding surface (6a) of the guiding pulley (6).

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4. Method as claimed in claim 3, wherein the roving (3) which is not
guided over the deflecting pulley (5) is guided by a rotatably
mounted pressure pulley (9) for uniting with the other roving (2) to
the guiding surface (6a) of the guiding pulley (6).
5. Method as claimed in one of the claims 1-4, wherein the spun self-
twist yarn (1) is guided in the yarn running direction (C) after the
guiding pulley (6) over a rotatably mounted pressure pulley (10).
6. Method as claimed in one of the claims 1-5, wherein the angle
range over which the roving (2) guided over the deflecting pulley
(5) bears on its guiding surface (5a) is between 70° and 200°,
preferably between 80o and 120°.
7. Method as claimed in one of the claims 1-6, wherein the angle
range over which the roving (2) guided over the deflecting pulley
(5) to the guiding pulley (6) bears on its guiding surface (6a) is
between 70° to 200°, preferably between 80° and 120°.
8. Device for production of a self-twist yarn with at least one false
twisting device (4) in which the at least two rovings (2,3) can
alternately be given areas with S and Z twisting which are
separated from one another by areas with no twisting, and a
twisting device in which at least two of the rovings (2,3) can be
brought together so that they spin together automatically to form a
self-twist yarn, whereby the areas of the rovings with no twisting
lie out of phase in the spun self-twist yarn, characterized in that the
twisting device is formed by at least one deflecting pulley (5) and a
guiding pulley (6), the deflecting pulley (5) deflecting at least one of the rovings (2) out of the original yarn running direction (C) and

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guiding it to a guiding pulley (6) on whose guiding surface (6a) it is brought together with at least one other roving (3),
9. Device as claimed in claim 8, wherein the guiding pulley (4) and
the or each deflecting pulley (5) exhibit a diameter of at least 10%
of the length (L) of the period of the alternating areas of the spun
self-twist yarn (1) with S and Z twisting.
10. Device as claimed in one of claims 8 or 9, wherein the or each
false twisting device (4) is formed by two rubbing rollers (7,8)
which are essentially cylindrical in form and arranged axially
parallel and turn in opposite directions about their axes (7a,,8a) and
oscillate axially relative to one another between two limit
positions.
11. Device as claimed in one of claims 8 to 10, wherein the guiding
pulley (6) and the or each deflecting pulley (5) are mounted
rotatably, their axes of rotation standing perpendicular to the plane
which is defined by the two rovings (2,3), and the guiding pulley
(6) being arranged in the yarn running direction (C) after the or
each deflecting pulley (S).
Method for production of a self-twist yarn (1) wherein firstly at least two rovings (2,3) are run through at least one false twisting device (4), through which the rovings (2,3) are each given periodically alternating areas with S and Z twisting which are separated from one another by areas with no twisting (0), and the rovings (2,3) are then brought together so that they spin together automatically due to their self-twist characteristics, the areas with no twisting (0) in the spun self-twist yarn (1) exhibiting a difference in phase ( ), characterized in that to produce the difference in phase ( ) at least one of the rovings (2), after running through the false twisting device (4), is guided over at least one deflecting pulley (5) to a guiding pulley (6) and the rovings (2,3) are brought together on the guiding surface (6a) of the guiding pulley (6).

Documents:

in-pct-2002-00223-kol abstract.pdf

in-pct-2002-00223-kol claims.pdf

in-pct-2002-00223-kol correspondence.pdf

in-pct-2002-00223-kol description(complete).pdf

in-pct-2002-00223-kol drawings.pdf

in-pct-2002-00223-kol form-1.pdf

in-pct-2002-00223-kol form-13.pdf

in-pct-2002-00223-kol form-18.pdf

in-pct-2002-00223-kol form-2.pdf

in-pct-2002-00223-kol form-26.pdf

in-pct-2002-00223-kol form-3.pdf

in-pct-2002-00223-kol form-5.pdf

in-pct-2002-00223-kol letters patent.pdf

in-pct-2002-00223-kol priority document.pdf

in-pct-2002-00223-kol reply f.e.r.pdf

in-pct-2002-223-kol-granted-abstract.pdf

in-pct-2002-223-kol-granted-claims.pdf

in-pct-2002-223-kol-granted-description (complete).pdf

in-pct-2002-223-kol-granted-drawings.pdf

in-pct-2002-223-kol-granted-form 2.pdf

in-pct-2002-223-kol-granted-specification.pdf

in-pct-2002-223-kol-priority document.pdf

in-pct-2002-223-kol-translated copy of priority document.pdf


Patent Number 212987
Indian Patent Application Number IN/PCT/2002/223/KOL
PG Journal Number 51/2007
Publication Date 21-Dec-2007
Grant Date 19-Dec-2007
Date of Filing 13-Feb-2002
Name of Patentee SAURER HAMEL AG.
Applicant Address TEXTILSTRASSE 2, CH-9320 ARBON
Inventors:
# Inventor's Name Inventor's Address
1 DEEG , THOMAS REUTLINGERSTRASSE 39, CH-8472 SEUZACH
PCT International Classification Number D01H 3/04
PCT International Application Number PCT/EP01/04812
PCT International Filing date 2001-04-28
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 100 32 708.7 2000-07-07 Germany