EP3371353B1 - Thread draw-off nozzle having notches extending radially to the nozzle bore - Google Patents

Description

The present invention relates to a thread draw-off nozzle for an open-end rotor spinning device with an inlet-side nozzle funnel and an outlet-side nozzle bore which adjoins the nozzle funnel. In the area of the nozzle funnel, notches are arranged which run essentially radially to the nozzle bore and which have an inlet wall and an impact wall as well as a radially outer notch inlet and a radially inner notch outlet.

Thread take-off nozzles have become known in the prior art for open-end rotor spinning devices in multiple designs. Thread take-off nozzles of this type have the task of deflecting the spun yarn as it is being pulled out of the spinning device and of imparting a false twist to the thread being pulled off. Since the real twist in the freshly spun thread is mainly introduced between the thread take-off nozzle and the take-off device, but does not propagate sufficiently into the rotor groove, the introduction of a false twist by means of the thread take-off nozzle can significantly increase the spinning stability. To introduce the false twist, the thread take-off nozzles have surface structures which have proven themselves in principle to improve the spinning stability, but at the same time also have a considerable influence on the quality of the spun thread. Spiral elevations or radially arranged notches are predominantly used as surface structures. Spiral nozzles are generally considered to be advantageous for the yarn quality, but often offer less spinning stability. Notched nozzles, on the other hand, are well suited to increase spinning stability, but are considered to be more aggressive with regard to the yarn quality.

Efforts have therefore already been made to find a thread take-off nozzle that meets both requirements equally. The DE 199 06 111 A1 , which discloses the preamble of claim 1, proposes, for example, a thread draw-off nozzle with notches arranged radially in the region of the nozzle funnel, the notches being designed asymmetrically. The asymmetrical notch is designed in such a way that the thread first runs gently through a very flat inlet wall to the bottom of the notch, where it is then stopped abruptly by the steep baffle. This asymmetrical configuration of the notches is intended to prevent the notches from jumping over through the circumferential thread.

After DE 103 18 305 A1 it is provided that a thread take-off nozzle is provided with radial, asymmetrical notches which are curved in a sickle shape. The curvature of the notches is carried out against the curvature of the crank-like rotating yarn. This is said to be able to achieve a different effect on the yarn by means of a single notch. In this way, an increased false twist effect is to be achieved in the area of the end face, which improves the spinning stability, while in the direction of the yarn take-off channel, the effect of the impact wall, which briefly stops the thread, should predominate.

From the DE 199 49 533 A1 Another embodiment of a trigger nozzle is known. This does not include any notches, but one or more depressions, which extend over a larger angular range of at least 10 ° or more and are designed in steps to the regular surface of the extraction nozzle. As a result, the yarn should completely lose contact with the surface of the draw-off nozzle, that is, it should skip a certain angular range. The false twist should be completely removed from the piece of yarn between the extraction nozzle and the rotor groove. This is to prevent the formation of unwanted tummy tucks in the yarn. Due to the more rapid lifting and bouncing of the thread however, an aggressive effect on the sound quality can also be expected here on the surface of the trigger nozzle.

The object of the present invention is to propose a thread draw-off nozzle which enables high spinning stability and yet reduces negative influences on the yarn quality.

The object is achieved with the features of claim one.

A thread take-off nozzle for an open-end rotor spinning device has an inlet-side nozzle funnel and an outlet-side nozzle bore which adjoins the nozzle funnel. In the area of the nozzle funnel, notches extending essentially radially to the nozzle bore are arranged, the notches having an inlet wall and a baffle wall as well as a radially outer notch inlet and a radially inner notch outlet. In the present thread take-off nozzle, it is provided that between the inlet wall of the notch and the baffle wall there is a preferably flat, flat notch floor. The inlet wall and the baffle therefore do not directly meet in the area of the notch base, which was often rounded in the prior art. The thread that runs in via the inlet wall therefore runs along the notch in a defined manner and is safely guided to the bottom of the notch. In contrast to this, the V-shaped notches used up to now, despite the gently descending inlet flanks, still prevented the thread from reaching the bottom of the notch, but jumping undefined from the inlet ramp to the outlet ramp.

The notch base preferably has a width between 0.16 mm and 0.22 mm, in particular between 0.18 mm and 0.20 mm. The thread can be gently braked as it travels over the notch floor and glides towards the baffle. The thread is thus safely exposed to the effect of the notch over a longer period of time, at the same time the thread-damaging effect of the notches is reduced. It has been shown that with such a width of the notch bottom, an optimal compromise between the effect of the notches, which increases the spinning stability, on the one hand, and the yarn quality, on the other hand, can be achieved.

It is therefore also advantageous if the notches have a flatter inlet wall and a steeper baffle. This also prevents the notches from jumping through the thread, and the thread is safely guided onto the baffle that temporarily restrains it.

For better propagation of rotation down to the rotor groove, it is also advantageous if the notch outlet is arranged in an inlet area of the nozzle bore. The notch thus extends into the nozzle bore and is therefore comparatively steep. The thread can run better into the notches and thus experiences a particularly significant change in length in the circumferential yarn leg. The change in length and thus also the thread tension peak generated by the notch is all the greater, the steeper the notch. Due to the steeper tapering of the notches into the nozzle bore, a smoother transition is achieved when reaching and leaving the notch, so that negative influences of the notches on the yarn quality can be avoided. It is advantageous if the notch outlet is arranged at a depth between 0.1 mm and 0.5 mm from an inlet of the nozzle bore. With such an arrangement of the notch outlet, the thread can be guided particularly securely into the notches and a steep notch is achieved. Since the notch is also offset on the nozzle funnel when viewed in the pull-off direction in the direction of the nozzle bore, it is further achieved that the leg-shaped piece of yarn passes less than before over the notch inlet. This also helps to avoid thread skipping. This also reduces the yarn damaging effect of the notch run-in and improves the yarn quality.

To achieve good yarn quality, it is also advantageous if the nozzle funnel has a circumferential recess in the area of the notch inlets, in particular a circumferential, preferably rounded, groove. The recess can directly adjoin the notch inlets; it is also possible that an upper area of the notches with the original notch inlets is removed by the recess and thus new notch inlets which now lie deeper in the nozzle funnel result at the transition from the recess to the notch. The recess itself can extend to the end face of the nozzle funnel or can only interrupt the surface of the nozzle funnel. Such a recess can further reduce an aggressive effect of the notch inlet on the thread. Instead of a circumferential groove, it is also possible to form the recess, for example by means of a spherical recess.

It is also advantageous if the inlet wall and / or the baffle wall as flat surfaces, ie. H. uncurved, are formed. The notch floor between the baffle wall and the inlet wall is preferably also designed as a flat surface. As a result, the thread is guided within the notch over its entire length in a defined manner and the manufacture of the thread take-off nozzle is thereby facilitated.

If the inlet wall and / or the baffle wall are kinked and / or curved, then a more gentle thread treatment can take place than in the case of an uncurved surface. The steep surface is shortened by the kinked or curved surface and continued by a flatter surface to the top of the nozzle.

It is particularly advantageous if the angle of the baffle to a notch plane is between 32.5 ° and 47.5 °, preferably between 35 ° and 45 °, particularly preferably between 37 ° and 42 °. The baffle is therefore comparatively flat. The release of the thread after his Braking through the baffle can also take place more gently and an undefined jumping of the thread can also be avoided.

In the case of a kinked or curved inlet wall and / or the baffle, it is advantageous if a first angle (β ₁ ) of a first part of the inlet wall and / or the baffle to a notch plane between 32.5 ° and 47.5 °, preferably between 35 ° and 45 °, particularly preferably between 37 ° and 42 ° and a second angle (β2) of a second part of the inlet wall (8) and / or the baffle wall (9) to the first part between 10 ° and 20 °, preferably between 13 ° and 17 °. With this, the thread is guided particularly gently.

For the safe guiding of the thread to the notch base or notch bottom, it is advantageous if the angle of the inlet wall to a notch center plane is between 50 ° and 65 °, preferably between 52 ° and 60 °, particularly preferably between 54 ° and 58 °.

The notch angle between the inlet wall and the baffle is therefore advantageously between 80 ° and 115 °, preferably between 85 ° and 110 ° and particularly preferably between 96 ° and 100 °. Such values have proven to be optimal in order to guide the thread safely into the notch and still slow down gently.

In order to safely release the thread again after braking, the depth of the notch is preferably between 0.14 mm and 0.25 mm, preferably between 0.16 mm and 0.22 mm and particularly preferably between 0.16 and 0.20 mm .

Figur 1

eine schematische Darstellung einer Offenendspinnvorrichtung mit einem Spinnrotor und eine Abzugsdüse,

Figur 2

eine schematische Darstellung einer Kerbe einer Fadenabzugsdüse mit einem Kerbenboden,

Figur 3

eine schematische Schnittdarstellung einer Fadenabzugsdüse mit einem Kerbauslauf im Eingangsbereich der Düsenbohrung,

Figur 4

eine schematische Schnittdarstellung einer Fadenabzugsdüse mit einer umlaufenden Ausnehmung,

Figur 5

eine schematische Schnittdarstellung einer weiteren Fadenabzugsdüse mit einer umlaufenden Ausnehmung,

Figur 6

eine Draufsicht auf eine Fadenabzugsdüse mit Kerben, sowie

Figur 7

eine weitere Ausführung einer Fadenabzugsdüse mit einer geknickten Prallwand.

Further advantages of the invention are described on the basis of the exemplary embodiments illustrated below. Show it:

Figure 1

1 shows a schematic representation of an open-end spinning device with a spinning rotor and a draw-off nozzle,

Figure 2

1 shows a schematic illustration of a notch of a thread draw-off nozzle with a notch bottom,

Figure 3

1 shows a schematic sectional illustration of a thread draw-off nozzle with a notch outlet in the entrance area of the nozzle bore,

Figure 4

2 shows a schematic sectional illustration of a thread draw-off nozzle with a circumferential recess,

Figure 5

2 shows a schematic sectional illustration of a further thread take-off nozzle with a circumferential recess,

Figure 6

a plan view of a thread take-off nozzle with notches, as well

Figure 7

another version of a thread take-off nozzle with a bent baffle.

Figure 1 shows a schematic sectional view of a spinning rotor 2 and a thread draw-off nozzle 1 in an open-end spinning device shown only partially in the present case. To produce a thread F, the spinning rotor 2 is fed with a fiber material dissolved in individual fibers in a known manner. The spinning rotor 2 rotates at high speeds during the yarn production, so that the fed fibers are deposited in the form of a fiber ring in the rotor groove 3 of the spinning rotor 2. The newly spun thread F is drawn off continuously via the thread take-off nozzle 1 and extends with its end into the rotor groove 3 of the spinning rotor 2. Due to the rotation of the spinning rotor 2, a crimp-like yarn leg thus arises, in which the fibers deposited in the rotor groove 3 are integrated .

The thread take-off nozzle 1 has in the usual way a cylindrical nozzle bore 6 and a nozzle funnel 5, which forms a curved yarn deflecting surface for the thread F to be drawn off. Finally, on the nozzle funnel 5, on the side of the thread take-off nozzle 1 facing away from the nozzle bore 6, there is an end face 16 of the thread take-off nozzle 1, which can be designed in different ways, for example flat, curved, or also sloping in the direction of the head diameter D _{K of} the thread take-off nozzle 1 . The nozzle bore 6 is generally coaxial with the axis of rotation 15 of the spinning rotor 2, so that the thread F drawn off is deflected by approximately 90 ° over the deflection surface of the nozzle funnel 5 during its withdrawal from the rotor groove 3. As described at the outset, it is desirable for the twist introduced into the thread to propagate as far as possible into the rotor groove 3 in order to achieve the best possible spinning stability. For this purpose, the surface of the nozzle funnel 5 is provided with notches 7 (see Figure 2 ) or surveys. Although these structures increase spinning stability, they can also impair yarn quality, especially in the case of notches.

Figure 2 shows a schematic section through a notch 7 of a thread take-off nozzle 1, with which a particularly good and safe effect of the notch 7 on the thread F can be ensured. The notch 7 has, in a manner known per se, an inlet wall 8 and an impact wall 9, which the thread F reaches in succession during its crank-shaped circulation via the nozzle funnel 5. The direction of rotation of the thread F is symbolized in the present case by an arrow. In contrast to previously known notch shapes of the prior art, which were always V-shaped, it is now provided that the inlet wall 8 and the baffle wall 9 do not directly adjoin one another, but rather a defined notch floor 12 with a defined width B between the inlet wall 8 and the baffle 9 extends. The notch bottom 12 is completely flat in the present case. The notch 7 thus has a simple geometric Structure, which is easy to manufacture. The arrangement of the notch base 12 between the inlet wall 8 and the baffle wall 9 ensures that the thread F in each case reaches the base of the notch, which is designed here as a flat notch base 12. Undefined jumping of the thread F from the inlet wall 8 directly onto the baffle 9, as was often the case in the prior art, can thereby be avoided. It is thus ensured that the thread F reaches the notch bottom 12 and thereby experiences a sufficient change in length in the circumferential yarn leg 15.

According to the present illustration, the safe reaching of the notch base 12 is further supported by the fact that the thread F is slowly and gently guided in the direction of the notch base 12 via a comparatively flat inlet wall 8. The angle α to a central notch plane 14 or to a parallel to it is preferably between 54 ° and 58 ° and is carried out, for example, at 56 °. The notch bottom 12 also has a width B between 0.18 mm and 0.24 mm. For example, the width B of the notch bottom is 0.22 mm. The angle β of the baffle 9 to the central notch plane 14, however, is preferably between 37 ° and 42 °. According to a particularly advantageous embodiment, the angle β is 40 °. With such an angle β of the baffle 9, the thread F can be braked in a desired manner in a particularly favorable manner, but can nevertheless be gently guided out of the notch 7 again. This results in a notch angle α + β between the inlet wall 8 and the baffle 9 of, for example, 96 °. It has also proven to be advantageous if the depth T of the notch 7 is between 0.16 mm and 0.20 mm. For example, the depth T is 0.18 mm. The notch shape shown thus not only helps to improve the spinning stability, but also to improve the yarn quality.

Figure 3 shows a schematic sectional view of a thread take-off nozzle 1, in which the notches 7 (in the present case, two notches 7 are each other) visible opposite) extend into the nozzle bore 6. It has proven to be particularly advantageous if the notch outlet 11, which in the present case is defined by the point of intersection or the line of intersection of the notch base 12 with the inner surface of the thread take-off nozzle 1, is at a distance A between 0.1 mm and 0.5 mm is located. For example, the distance A is 0.25 mm. The entrance of the nozzle bore 6 is defined as the beginning of the constant inner cross section of the thread take-off nozzle 1. In contrast, the thread draw-off nozzle 1 has a constantly changing internal cross section in the region of the nozzle funnel 5. In the case of a tangential transition of the nozzle funnel 5 into the nozzle bore 6, the entrance of the nozzle bore 6 is thus defined by the tangential edge shown here.

The notches 7 are thus in a position in which the thread F is no longer pressed so strongly onto the surface of the nozzle funnel 5. Such a comparatively steep notch 7 thus has a positive effect on the yarn quality due to the fact that the circumferential yarn leg 4 brushes less strongly over the notch inlet 10 and is also advantageous for the spinning stability. The notch inlet 10 is in turn defined in the case of conventional V-shaped notches by the common intersection of the inlet wall 8 and the baffle 9 with the inner surface of the nozzle funnel 5 or in the present case by the line of intersection of the notch base 12 with the inner surface of the nozzle funnel located on the input side.

Figure 4 shows a further embodiment of a thread draw-off nozzle 1, in which the yarn-damaging effect of the notch inlet 10 is mitigated by a circumferential recess 13, here a circumferential groove 13a. The circumferential groove 13a preferably has a radius R ₁ between 0.15 mm and 0.3 mm and, in the present case, is designed such that it merely interrupts the surface of the nozzle funnel 5. Likewise, the circumferential groove 13a could also be designed such that it extends into the end face 16 of the thread take-off nozzle 1. The notch inlets 10 or comparatively sharp transition between the curved surface of the nozzle funnel 5 and the notch 7 can thereby be made gentler.

Figure 5 shows another embodiment of a thread draw-off nozzle 1, in which the notch inlets 10 have been defused by a spherical recess 13b. The radius R _{2 of} the spherical recess 13b is preferably matched to the inner diameter D _{I of} the nozzle bore 6 and is between 0.7 ^∗ D _I and 0.9 ^∗ D _I. For example, the radius R _{2 is} 0.8 ^∗ D _I. The aggressive, yarn-damaging effect of the notch inlets 10 can hereby be significantly reduced.

Figure 6 finally shows a plan view of a thread take-off nozzle 1 with the notch 7 described with a defined notch bottom 12. The arrow again shows the direction of rotation of the circumferential yarn leg 4. The flatter inlet wall 8 and the steeper baffle wall 9 can also be seen. In the present case, a total of four notches 7 are arranged evenly distributed over the circumference, but an embodiment with only three notches 7 or more than four notches 7 would also be possible.

In Figure 7 a notch 7 is shown, in which the baffle 9 is kinked. The first part of the baffle wall 9 facing the notch base 12 is inclined at an angle β ₁ to the notch center plane 14. The second part of the baffle 9 facing the edge of the thread draw-off nozzle 1 is flatter and has a second angle β ₂ . With this type of notch 7, a gentler thread treatment is possible than with the notches shown above. since the baffle 9 does not slow down the thread as much. Such a kinked design is also possible for the inlet wall 8 in addition or as an alternative to the kinked baffle 9.

It has been shown that in particular a combination of a notch 7 with a defined notch base 12 and a notch 7 with a notch outlet 11 an optimal compromise between spinning stability on the one hand and yarn quality on the other hand can be achieved within the nozzle bore 6.

Reference list

1

Thread take-off nozzle

2nd

Spinning rotor

3rd

Rotor groove

4th

all-round twine

5

Nozzle funnel

6

Nozzle bore

7

score

8th

Inlet wall

9

Baffle

10th

Notch enema

11

Notch runout

12th

Notch floor

13

Recess
13a groove
13b spherical recess

14

Notch level

15

Spinning rotor axis of rotation

16

Face

B

Notch floor width

T

Depth of notch

F

thread

D _K

Head diameter

D _I

Inner diameter of the nozzle bore

A

Distance of the notch outlet from the entrance to the nozzle bore

α

Angle of the inlet wall

β

Baffle angle

R ₁

Radius of the groove

R ₂

Radius of the sphere

Claims (13)

1. Thread draw-off nozzle (1) for an open-end rotor spinning device with an entrance-side nozzle funnel (5) and an exit-side nozzle bore (6) adjoining the nozzle funnel (5), with notches (7) extending in a manner essentially radial to the nozzle bore (6) arranged in the area of the nozzle funnel (5); these feature an inlet wall (8) and a baffle wall (9), along with a radially outer notch inlet (10) and a radially inner notch outlet (11), characterized in that a notch bottom (12) that is preferably formed to be flat, preferably even, is arranged between the inlet wall (8) and the baffle wall (9).
2. Thread draw-off nozzle according to the preceding claim, characterized in that the notch bottom (12) features a width (B) of between 0.16 mm and 0.28 mm, in particular between 0.18 mm and 0.24 mm.
3. Thread draw-off nozzle according to one of the preceding claims, characterized in that the notches (7) feature a flatter inlet wall (8) and a steeper baffle wall (9).
4. Thread draw-off nozzle according to one of the preceding claims, characterized in that the notch outlet (11) is arranged in an entrance area of the nozzle bore (6).
5. Thread draw-off nozzle according to one of the preceding claims, characterized in that the notch outlet (11) is arranged at a spacing (A) of between 0.1 mm and 0.5 mm away from an entrance of the nozzle bore.
6. Thread draw-off nozzle according to one of the preceding claims, characterized in that the nozzle funnel (5) features, in the area of the notch inlets (10), a circumferential recess (13), in particular a circumferential, preferably rounded, groove (13a).
7. Thread draw-off nozzle according to one of the preceding claims, characterized in that the inlet wall (8) and/or the baffle wall (9) are formed to be even.
8. Thread draw-off nozzle according to one of the preceding claims, characterized in that the inlet wall (8) and/or the baffle wall (9) are formed to be kinked and/or bent.
9. Thread draw-off nozzle according to one of the preceding claims, characterized in that an angle (β) of the baffle wall (9) to a center notch plane (14) amounts to between 32.5° and 47.5°, preferably between 35° and 45°, more preferably between 37° and 42°.
10. Thread draw-off nozzle according to one of the preceding claims, characterized in that a first angle (β₁) of a first part of the inlet wall (8) and/or the baffle wall (9) to a center notch plane (14) amounts to between 32.5° and 47.5°, preferably between 35° and 45°, more preferably between 37° and 42°, and a second angle (β₂) of a second part of the inlet wall (8) and/or the baffle wall (9) to the first part amounts to between 10° and 20°, preferably between 13° and 17°.
11. Thread draw-off nozzle according to one of the preceding claims, characterized in that an angle (a) of the inlet wall (8) to a center notch plane (14) amounts to between 50° and 65°, preferably between 52° and 60°, more preferably between 54° and 58°.
12. Thread draw-off nozzle according to one of the preceding claims, characterized in that the notch angle (α + β) between the inlet wall (8) and the baffle wall (9) amounts to between 80° and 115°, preferably between 85° and 110°, more preferably between 96° and 100°.
13. Thread draw-off nozzle according to one of the preceding claims, characterized in that the depth (T) of the notch (7) amounts to between 0.14 mm and 0.25 mm, preferably between 0.16 mm and 0.22 mm and more preferably between 0.16 and 0.20 mm.

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