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

Abstract

A thread draw-off nozzle for an open-end rotor spinning device includes an entrance-side nozzle funnel and an exit-side nozzle bore adjoining the nozzle funnel. A plurality of notches are arranged in the nozzle funnel and extend essentially radial to the nozzle bore. Each notch has an inlet wall, a baffle wall, a radially outer notch inlet, and a radially inner notch outlet. Each notch further includes an essentially flat notch bottom arranged between the inlet wall and the baffle wall.

Claims

1. A thread draw-off nozzle for an open-end rotor spinning device, comprising: an entrance-side nozzle funnel; an exit-side nozzle bore adjoining the nozzle funnel; a plurality of notches arranged in the nozzle funnel and extending radial to the nozzle bore, each notch comprising an inlet wall, a baffle wall, a radially outer notch inlet, and a radially inner notch outlet; each notch further comprising a notch bottom with a width (B) of between 0.18 mm and 0.24 mm between the inlet wall and the baffle wall; wherein the notch inlet is in the nozzle funnel spaced apart from a front surface of the nozzle funnel; and wherein, for each notch, the baffle wall has at least one baffle wall angle, the inlet wall has at least one inlet wall angle, and the at least one baffle wall angle is steeper than the at least one inlet wall angle relative to the notch bottom.

2. The thread draw-off nozzle according to claim 1, wherein the notch outlet is arranged in an entrance area of the nozzle bore.

3. The thread draw-off nozzle according to claim 1, wherein the notch outlet is arranged at a spacing of 0.1 mm to 0.5 mm away from an entrance of the nozzle bore.

4. The thread draw-off nozzle according to claim 1, wherein the nozzle funnel comprises a circumferential recess in an area of the notch inlets.

5. The thread draw-off nozzle according to claim 1, wherein one or both of the inlet wall and the baffle wall are formed of flat surfaces.

6. The thread draw-off nozzle according to claim 1, wherein one or both of the inlet wall and the baffle wall are formed of kinked or bent surfaces.

7. The thread draw-off nozzle according to claim 1, wherein an angle (.sub.2) of the baffle wall to a center notch plane is between 32.5 and 47.5.

8. The thread draw-off nozzle according to claim 1, wherein the at least one baffle wall angle comprises a first angle (.sub.1) and a second angle (.sub.2) wherein the first angle (.sub.1) of a first part of the baffle to a center notch plane is between 32.5 and 47.5, and the second angle (.sub.2) of a second part of the baffle wall to the first part of the baffle wall is between 10 and 20.

9. The thread draw-off nozzle according to claim 1, wherein the at least one inlet wall angle comprises an angle (), wherein the angle () of the inlet wall to a center notch plane is between 50 and 65.

10. The thread draw-off nozzle according to claim 1, wherein each notch comprises a depth (T) between 0.14 mm and 0.25 mm.

11. The thread draw-off nozzle according to claim 1, wherein the notch bottom is flat.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Additional advantages of the invention are described on the basis of the following presented embodiments. The following is shown:

(2) FIG. 1 is a schematic view of an open-end spinning device with a spinning rotor and a draw-off nozzle;

(3) FIG. 2 is a schematic view of a notch of a thread draw-off nozzle with a notch bottom;

(4) FIG. 3 is a schematic sectional view of a thread draw-off nozzle with a notch outlet in the entrance area of the nozzle bore;

(5) FIG. 4 is a schematic sectional view of a thread draw-off nozzle with a circumferential recess;

(6) FIG. 5 is a schematic sectional view of an additional thread draw-off nozzle with a circumferential recess;

(7) FIG. 6 is a top view of a thread draw-off nozzle with notches;

(8) FIG. 7 is an additional embodiment of a thread-draw-off nozzle with a kinked baffle wall; and

(9) FIG. 8 is an embodiment of a thread draw-off nozzle with kinked baffle and inlet walls.

DETAILED DESCRIPTION

(10) Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein.

(11) FIG. 1 shows a schematic sectional view of a spinning rotor 2 and a thread draw-off nozzle 1 in an open-end spinning device, which is shown only partially in the present case. To produce a thread F, the spinning rotor 2 is fed in a known manner with a fiber material broken down into individual fibers. During yarn production, the spinning rotor 2 runs at high rotational speeds, such that the fibers that are fed are deposited in the rotor groove 3 of the spinning rotor 2 in the form of a fiber ring. The newly spun thread F is drawn off continuously via the thread draw-off nozzle 1 and, with its end, extends into the rotor groove 3 of the spinning rotor 2. Thus, due to the rotation of the spinning rotor 2, a crank-like circumferential yarn shank 4, in which the fibers deposited in the rotor groove 3 are integrated, arises.

(12) The thread draw-off nozzle 1 features, in the customary manner, a cylindrical nozzle bore 6 and a nozzle funnel 5, which forms a curved yarn deflection surface for the thread F to be drawn off. Finally, a front surface 16 of the thread draw-off nozzle 1 adjoins the nozzle funnel 5, on the side of the thread draw-off nozzle 1 turned away from the nozzle bore 6; such front surface 16 can be formed to be sloping in different manners, for example, flat, curved, or in the direction of the head diameter D.sub.K of the thread draw-off nozzle 1. The nozzle bore 6 is typically coaxial relative to the axis of rotation 15 of the spinning rotor 2, such that, during its drawing off out of the rotor groove 3, the drawn-off thread F is deflected over the deflection surface of the nozzle funnel 5 by about 90. As described above, it is desirable that the rotation introduced into the thread propagates 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 FIG. 2) or elevations. Although such structures increase spinning stability, they can also impair yarn quality, in particular in case that there are notches.

(13) FIG. 2 shows a schematic section through a notch 7 of a thread draw-off nozzle 1, with which a particularly good and reliable effect of the notch 7 on the drawn-off thread F can be ensured. The notch 7 features, in a manner known per se, an inlet wall 8 and a baffle wall 9, which the thread F reaches in succession during its crank-shaped circulation over the nozzle funnel 5. In the present case, the direction of rotation of the thread F is symbolized by an arrow. However, in contrast to previously known notch shapes of the state of the art, which have always been designed to be V-shaped, it is now provided that the inlet wall 8 and the baffle wall 9 do not directly adjoin one another; rather, a defined notch bottom 12 with a defined width B extends between the inlet wall 8 and the baffle wall 9. In the present case, the notch bottom 12 is formed to be completely flat. Thereby, the notch 7 features a simple geometric structure, which is easy to manufacture. The arrangement of the notch bottom 12 between the inlet wall 8 and the baffle wall 9 ensures that the thread F reaches the notch base in each case, which in this case is designed as a flat notch bottom 12. An undefined jumping of the thread F from the inlet wall 8 directly on the baffle wall 9, as it often occurred in the state of the art, can thereby be avoided.

(14) It is thus ensured that the thread F reaches the notch bottom 12 and thereby undergoes a sufficient change in length in the circumferential yarn shank 4.

(15) According to the present illustration, the secure reaching of the notch bottom 12 is still supported by the fact that the thread F is led over a comparatively flat inlet wall 8 slowly and gently relative to and in the direction of the notch bottom 12. The angle to a center notch plane 14 or to a parallel thereto, as the case may be, preferably amounts to between 54 and 58 and is designed, for example, at 56. The notch bottom 12 further features a width B of between 0.18 mm and 0.24 mm. For example, the width B of the notch bottom amounts to 0.22 mm. However, the angle of the baffle wall 9 relative to the center notch plane 14 preferably amounts to between 37 and 42. According to a particularly advantageous embodiment, the angle amounts to 40. With such an angle of the baffle wall 9, the thread F can be braked in a particularly advantageous manner, indeed in a desirable manner, but can nevertheless be led out of the notch in a gentle manner. This results in a notch angle of + between the inlet wall 8 and the baffle wall 9 of for example, 96. It has also proven to be advantageous if the depth T of the notch 7 amounts to between 0.16 mm and 0.20 mm. For example, the depth T amounts to 0.18 mm. Thus, the notch shape that is shown contributes not only to improving spinning stability, but also to improving yarn quality.

(16) FIG. 3 shows, in a schematic sectional view, a thread draw-off nozzle 1, with which the notches 7 (in the present case, two notches 7 can be seen opposite one another) extend into the nozzle bore 6. It has proved to be particularly advantageous if the notch outlet 11, which is defined in the present case by the exit-side intersection point or the exit-side intersection line of the notch bottom 12 with the inner surface of the thread draw-off nozzle 1, is at a spacing A of between 0.1 mm and 0.5 mm. For example, the spacing A amounts to 0.25 mm. The entrance of the nozzle bore 6 is defined as the beginning of the constant inner cross-section of the thread draw-off nozzle 1. By contrast, the thread draw-off nozzle 1 in the area of the nozzle funnel 5 features an ever-changing inner cross-section. 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.

(17) Thus, the notches 7 are in a position in which the thread F is no longer pressed so strongly onto the surface of the nozzle funnel 5. Thus, such a comparatively steep notch 7 has a positive effect on yarn quality, due to the fact that the circumferential yarn shank 4 sweeps less strongly through the notch inlet 10, and is also advantageous for spinning stability. In the case of conventional V-shaped notches, the notch inlet 10 is in turn defined by the common intersection point of the inlet wall 8 and the baffle wall 9 with the inner surface of the nozzle funnel 5 or, in the present case, by the entrance-side intersection line of the notch bottom 12 with the inner surface of the nozzle funnel.

(18) FIG. 4 shows an additional embodiment of a thread draw-off nozzle 1, with which the yarn-damaging effect of the notch inlet 10 is defused by a circumferential recess 13, in this case a circumferential groove 13a. The circumferential groove 13a preferably features a radius R1 of between 0.15 mm and 0.3 mm, and in the present case is designed such that it only breaks up the surface of the nozzle funnel 5. Likewise, however, the circumferential groove 13a could also be designed such that it reaches the front surface 16 of the thread draw-off nozzle 1. Thereby, the notch inlets 10 or the comparatively sharp transition between the curved surface of the nozzle funnel 5 and the notch 7 can be configured to be more gentle.

(19) FIG. 5 shows another embodiment of a thread draw-off nozzle 1, with which the notch inlets 10 were mitigated by a spherical recess 13b. The radius R.sub.2 of the spherical recess 13b is preferably matched to the inner diameter D.sub.I (FIG. 3) of the nozzle bore 6, and amounts to between 0.7*D.sub.I and 0.9*D.sub.I. For example, the radius R.sub.2 amounts to 0.8*D.sub.I. The aggressive, yarn-damaging effect of the notch inlets 10 can thereby be substantially reduced.

(20) Finally, FIG. 6 also shows a top view of a thread draw-off nozzle 1 with the described notch 7 with a defined notch bottom 12. The direction of rotation of the circumferential yarn shank 4 is in turn shown by the arrow. Furthermore, the flatter inlet wall 8 and the steeper baffle wall 9 can be seen. In the present case, a total of four notches 7 are arranged evenly across the circumference; likewise, an embodiment with only three notches 7 or more than four notches 7 would be possible.

(21) In FIG. 7, a notch 7 is shown, in which the baffle wall 9 is formed to be kinked. The first part of the baffle wall 9 turned towards the notch bottom 12 is inclined at an angle .sub.1 to the center notch plane 14. The second part of the baffle wall 9 turned towards the edge of the thread draw-off nozzle 1 is formed to be more flat and features a second angle .sub.2. With this type of notch 7, a thread treatment that is more gentle than with the notches shown above is possible, since the baffle wall 9 does not brake the thread too strongly. Such a kinked formation is also possible for the inlet wall 8, in addition to or as an alternative to the kinked baffle wall 9, as shown in FIG. 8, wherein angles 1 and 2 reflect the kink in the inlet wall 8.

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

(23) Modifications and variations can be made to the embodiments illustrated or described herein without departing from the scope and spirit of the invention as set forth in the appended claims.

LIST OF REFERENCE SIGNS

(24) 1 Thread draw-off nozzle 2 Spinning rotor 3 Rotor groove 4 Circumferential yarn shank 5 Nozzle funnel 6 Nozzle bore 7 Notch 8 Inlet wall 9 Baffle wall 10 Notch inlet 11 Notch outlet 12 Notch bottom 13 Recess 13a Groove 13b Spherical recess 14 Center notch plane 15 Axis of rotation of the spinning rotor 16 Front surface B Width of the notch bottom T Depth of the notch F Thread D.sub.K Head diameter D.sub.I Inner diameter of the nozzle bore A Spacing of the notch outlet from the entrance of the nozzle bore Angle of the inlet wall Angle of the baffle wall R.sub.1 Radius of the groove R.sub.2 Radius of the sphere