Air spinning machine and a method for producing a yarn

Abstract

An air spinning machine for producing a yarn from a fiber structure includes a spinneret with an internal eddy chamber. A spindle in the spinneret has an intake opening and extends into the eddy chamber. An annular gap is formed between an outside surface of the spindle and an inside wall of the eddy chamber. Air jets in the spinneret introduce air into the eddy chamber to impart twist to the fiber structure at the intake opening. An interior draw-off channel in the spinneret has a longitudinal axis by means of which the yarn is withdrawn from the eddy chamber. The air jets are aligned in a direction relative to a front side of the spindle around the intake opening so that some of the air introduced via the air jets during a spinning operation enters the annular gap and a remainder of the air enters the draw-off channel.

Claims

1. An air spinning machine for producing a yarn from a fiber structure, comprising: a spinneret with an internal eddy chamber; an intake to the eddy chamber for admission of the fiber structure; a yarn-forming element in the spinneret in the form of a spindle having an intake opening, the yarn-forming element extending at least partially into the eddy chamber; an annular gap formed between an outside surface of the spindle and an inside wall of the eddy chamber facing the spindle; air jets in the spinneret by means of which air is introduced into the eddy chamber to impart a twist to the fiber structure in a region of the intake opening; an interior draw-off channel in the spinneret having a central longitudinal axis by means of which the yarn is withdrawn from the eddy chamber; the air jets aligned in a direction relative to a front side of the spindle around the intake opening so that some of the air introduced via the air jets during a spinning operation enters the annular gap and a remainder of the air enters the draw-off channel; and wherein each air jet comprises a central axis, a shortest distance (a) running perpendicular to the central axis and between the central axis and a reference plane (B) that runs parallel to the central axis and contains the central longitudinal axis of the draw-off channel conforms to the following formula:
a=d/2+D/2+b, wherein d corresponds to an inside diameter of the air jet; D corresponds to an inside diameter of the draw-off channel in a cylindrical region adjacent the intake opening; b corresponds to a distance between an inside surface of the air jet facing the draw-off channel and an inside surface of the draw-off channel in the cylindrical region facing the air jet; where a has a value of −0.7 mm to 8.0 mm; where d has a value of 0.2 mm to 2.0 mm; where D has a value of 0.4 mm to 12.0 mm; and where b has a value of −1.5 mm to 5.0 mm.

2. The air spinning machine according to claim 1, wherein the air jets run in a plane between the intake opening and a tangent to the inside wall of the eddy chamber, the tangent running parallel to a central axis of the respective air jet.

3. The air spinning machine according to claim 1, wherein b has a value of less than half the inside diameter (D) of the draw-off channel.

4. The air spinning machine according to claim 1, wherein b has a value less than a wall thickness (W) of the spindle in the cylindrical region of the draw-off channel.

5. The air spinning machine according to claim 1, wherein the air jets comprise boreholes with an imaginary straight extension that intersects the spindle.

6. The air spinning machine according to claim 5, wherein the air jets comprise a central axis with an imaginary linear extension that intersects the spindle.

7. The air spinning machine according to claim 6, wherein the imaginary linear extension of the central axis intersects a wall of the spindle without thereby intersecting the draw-off channel.

8. A method for producing a yarn from a fiber structure during a spinning operation with the air spinning machine according to claim 1, comprising introducing aft into the eddy chamber with the air jets during the spinning operation such that some of the introduced air enters the annular gap and the remainder of the introduced air enters the draw-off channel.

9. The method according to claim 8, wherein some of the introduced air strikes a front side of the spindle surrounding the intake opening of the spindle and is thereby distributed by the spindle.

10. The method according to claim 8, wherein most of the introduced air enters the annular gap.

11. The method according to claim 10, wherein a maximum of 30% of the introduced air enters the draw-off channel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Additional advantages of the invention are described in the following embodiments. In the schematic drawings:

(2) FIG. 1 shows a side view of a detail of an air spinning machine;

(3) FIG. 2 shows a cross section through a detail of a known spinneret;

(4) FIG. 3 shows a sectional diagram of the spinneret illustrated in FIG. 2 with a section along the interface S;

(5) FIGS. 4a, 4b show sectional diagrams of spinnerets according to the invention;

(6) FIG. 5 shows a possible air flow within the spinneret shown in FIG. 4b;

(7) FIG. 6 shows a detail of FIG. 4a;

(8) FIGS. 7a, b shows a top view of a spinneret in the area of the fiber guide element;

(9) FIG. 8 shows a side view of a detail of an air spinning machine; and

(10) FIG. 9 shows a top view of a detail of an air spinning machine.

DETAILED DESCRIPTION

(11) 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.

(12) FIG. 1 shows a schematic view of a detail of an air spinning machine. The air spinning machine may comprise as needed a drawing device having a plurality of drawing device rollers 21 and individual small belts 22 as needed, wherein the drawing device is supplied with a fiber structure 1 for example in the form of a doubled drawn sliver during the spinning operation.

(13) Furthermore, the air spinning machine shown here has one or more spinnerets 2 arranged next to one another, each having an interior eddy chamber 3 in which the fiber structure 1 and/or at least some of the fibers of the fiber structure 1 are provided with a twist (the exact mode of operation of the spinneret 2 is described in greater detail below).

(14) In addition, the air spinning machine may comprise a plurality of cooperating draw-off rollers 25 as well as a winding device (not shown), which is downstream from the draw-off rollers 25 and with the help of which the yarn 27 leaving the spinneret 2 through on outlet 26 can be wound onto a sleeve 23 to form a bobbin 24. The air spinning machine according to the invention need not necessarily have a drawing device as illustrated in FIG. 1. The draw-off rollers 25 are not absolutely necessary.

(15) The spinning machine shown here operates according to an air spinning method. To form the yarn 27, the fiber structure 1, arranged above an intake 4, in which a so-called fiber guide element 20 is preferably arranged, is guided into the eddy chamber 3 of the spinneret 2 (see also FIG. 2), where it receives a twist, i.e., at least some of the free fiber ends of the fiber structure 1 are captured by an air stream created by air jets 10 arranged suitably in an eddy chamber wall 29 surrounding the eddy chamber 3. Some of the fibers here are pulled at least a certain distance out of the fiber structure 1 and wound around the tip of a yarn-forming element, which is in the form of a spindle 6 protruding into the eddy chamber 3. Ultimately, the free fiber ends are also drawn in the direction of the intake opening 5 and are thereby wrapped as so-called winding fibers around the core fibers running centrally, resulting in a yarn 27 having the desired twist because the fiber structure 1 is drawn off through a draw-off channel 12 arranged inside the spindle 6 and out of the eddy chamber 3 by an intake opening 5 arranged in the area of the front side 13 of the spindle 6, facing in the direction of the intake 4.

(16) In general, it should be clarified at this point that the yarn 27 produced may fundamentally be any fiber structure, which is characterized in that an exterior portion of the fibers (so-called winding fibers) is wrapped around an inner portion of the fibers, preferably without a twist, to impart the desired strength to the yarn 27.

(17) The invention also includes an air spinning machine with the help of which the so-called roving can be produced. Roving is yarn 27 have a relatively small amount of winding fibers and/or a yarn 27, in which the winding fibers are wound relatively loosely around the inner core, so that the yarn 27 remains drawable. This is crucial, for example, when the yarn 27 that is produced is or must be drawn again with the help of a drawing device on a downstream textile machine (for example, a ring spinning machine) to be suitable for further processing.

(18) With regard to the air jets 10, it should be pointed out here again as a purely precautionary measure that such air jets should usually be aligned in such a way that jointly they created an air flow having a uniform direction of twist in the same direction. The individual air jets 10 here are arranged in rotational symmetry to one another.

(19) Furthermore, FIG. 2 shows that an annular gap 9, preferably running at least partially in rotational symmetry with the longitudinal axis 11 of the spindle 6, is formed between the outer surface 7 of the spindle 6 and the inside wall 8 of the eddy chamber 3 (i.e., the surface of the eddy chamber wall facing in the direction of the spindle 6). In the approaches known so far, all of the air introduced through the air jets 10 would leave the eddy chamber 3 via this annular gap 9, wherein the air would usually be drawn off downward through an air suction exhaust (not shown) out of the annular gap 9 (based on FIG. 2).

(20) In this context, reference should also be made to FIG. 3, which shows a section of the spinneret 2 illustrated along the sectional plane in FIG. 2, shown here along the sectional plane S. The air jets 10 are projected into the sectional plane S for the sake of better comprehensibility. The same thing is also true of FIGS. 4 through 6, which are described in greater detail below.

(21) FIG. 2 indicates, the known state-of-the-art air jets 10 are explicitly oriented in such a way that all of the air 28 (FIG. 5) introduced enters the annular gap 9 between the eddy chamber wall 29 and the spindle 6 because this was hoped to yield a particularly homogenous eddy air flow (which is also the reason why the known state-of-the-art air jets 10 open tangentially into the eddy chamber 3). The imaginary extension 16 of the central axis 14 of the respective air jet 10 (only one of several of which is shown in FIGS. 3 through 6 for reasons of simplicity) does not intersect the spindle wall 17 in this case.

(22) Whereas the resulting vacuum in the area of the fiber guide element 20 is important for drawing the fiber structure 1 through the intake 4 into the spinneret 2, it also causes an unwanted air flow, which extends from the outlet 26 of the spinneret 2 through the draw-off channel 12, which is bordered by an inside surface 18 of the spindle 6, in the direction of the intake opening 5 of the spindle 6 and results in a negative effect on the yarn quality.

(23) Therefore, in contrast with the prior art, it is now proposed that the air jets 10 should be oriented in such a way that some of the air 28 introduced into the eddy chamber 3 via the air jets 10 should enter the annular gap 9 and some of it should enter the draw-off channel 12 through the intake opening 5.

(24) Possible orientations are illustrated in FIGS. 4a and 4b which correspond in principle to the representations in FIG. 3 (i.e., here again the air jets 10 are projected into the sectional plane).

(25) In contrast with the orientation of the air jets 10 shown in FIG. 3, the air jets 10 shown in FIGS. 4a and 4b are shifted in the direction of the draw-off channel 12, so that they no longer open tangentially into the eddy chamber 3. Whereas the shift in FIG. 4a has taken place in such a way that the imaginary extension 16 of the central axis 14 of the respective air jet 10 runs outside of the spindle 6, said extension 16 in the case of FIG. 4b intersects the spindle wall 17.

(26) In both cases, however, the air jet 10 is aligned in such a way that its imaginary extension 15 intersects the spindle wall 17. Said extension 15 of the air jet 10 and the front side 13 of the spindle 6 thus overlap in the top view shown in FIGS. 4a and 4b.

(27) The effect of this alignment is now shown schematically in FIG. 5 where the variant shown in FIG. 4b is illustrated. As illustrated graphically by the path of the air 28, some of the air 28 introduced by the air jets 10 into the eddy chamber 3 enters the annular gap 9, while the rest of the air 28 enters the draw-off channel 12. This amount of introduced air 28 then means that relatively little air 28 or none at all can flow opposite the direction of transport of the yarn 27 through the draw-off channel 12, i.e., from the inlet 26 of the spinneret 2 in the direction of the intake opening 5 of the spindle 6. This permits production of a yarn 27 of a particularly high quality.

(28) Possible advantageous dimensions are shown in FIG. 6, which for the sake of simplicity shows only a detail of a sectional diagram corresponding to FIGS. 4 and 5.

(29) As explained in the previous description, it is advantageous if the inside diameter D of the draw-off channel 12 in the area of a section downstream from the intake opening 5 of the spindle 6 has a value of 0.4 mm to 3.0 mm in the case of a spindle 6 for spinning traditional yarn or has a value of 2.0 mm to 10.0 mm for a spindle 6 for spinning roving, wherein the inside diameter d of the spinneret 2 should preferably have a value of 0.2 mm to 2.0 mm.

(30) Furthermore, it has also proven advantageous if the shortest distance a between the corresponding central axis 14 and a reference plane B runs parallel to this central axis 14 and contains the longitudinal axis 11 of the draw-off channel 12 (see FIG. 6), said distance running perpendicular to the respective central axis 14 has a value of −0.7 mm to 5.6 mm when spinning traditional yarn and 1.5 to 8.0 mm when spinning roving. This value is in turn comprised of half the inside diameter d of the air jet 10 and half the inside diameter D of the draw-off channel 12 as well as a distance b the value of which is −1.5 mm to 5.0 mm. In particular, b should have a value less than the value of the wall thickness W of the spindle wall 17, which is also identified in FIG. 6.

(31) Finally FIG. 6 shows that the air jets 10 should preferably have a certain value and be arranged with an offset based on a tangent 19 of the inside wall 8 of the eddy chamber 3 in the direction of the longitudinal axis 11 of the spindle 6.

(32) In conclusion, reference should be made to FIGS. 7 and 8, which relate to another advantageous aspect of a novel air spinning machine. In this context it should be pointed out that the spatial orientation in most of the figures is represented by a coordinate system, in which the multiple diagrams in the figures are shown with the same angle of view (e.g., FIGS. 1 and 8 and/or 3 to 6 this was omitted for reasons of simplicity).

(33) As shown by a comparison of FIGS. 7a (prior art illustrated) and 7b (novel), it may be advantageous if the fiber guide element 20 is arranged so that it is rotated about the X axis. In this case, the fiber structure 1 is deflected in Z direction, i.e., in a direction running parallel to the axes of rotation of the drawing mill rollers 21 and soon as the fiber structure 1 has passed through the fiber guide element 20.

(34) In addition or alternatively, it may also be advantageous if the spinneret 2 is tilted about the Z axis out of the position shown in FIGS. 1 and 8, so that the longitudinal axis 11 of the spindle 6 and the transport direction of the fiber structure 1 are no longer parallel to one another within the drawing device, with a corresponding angle of inclination between 0° and 15° being preferred. Finally, it is also conceivable for this spinneret 2 to be tilted about the Y axis or shifted along the Z and/or Y axis. The offset in the direction of the Y axis should amount to max. 10 mm, where the offset is based on the embodiment in which the fiber structure 1 passing through the drawing mill and the longitudinal axis 11 of the spindle 6 are colinear.

(35) In conclusion, reference is made to FIG. 9 in this context. This shows in principle a top view of the detail shown in FIG. 8, wherein a guide 30 is also illustrated for the fiber structure 1. The guide 30 (several of which may also be present) serves the guide the fiber structure 1 on its path in and through the drawing device, wherein the guide 30 ensures that the fiber structure 1 takes its predetermined path on the one hand and on the other hand is compressed laterally to a predetermined extent (for example by a funnel shape of the guide 30).

(36) Furthermore FIG. 9 shows that it has been customary in the past for the spinneret 2 to be placed in such a way that the fiber structure 1 enters the spinneret 2 and/or the intake 4 of the eddy chamber 3 in such a way that it is approximately colinear with the longitudinal axis 11 of the spindle 6.

(37) As already indicated above, however, it may also be advantageous if the spinneret 2 is shifted in the Z axis (upward or downward with respect to FIG. 9) with the same position of the drawing mill rollers 21 in comparison with FIG. 9, wherein the amount of the displacement should preferably be between 2 mm and 30 mm, i.e., the smallest distance between the longitudinal axis 11 of the spindle 6 and a midline of the fiber structure 1 should be between 2 mm and 30 mm.

(38) The present invention is not limited to the embodiments illustrated and described here. Modifications within the scope of the patent claims are equally possible as is any combination of the described features, even if they are illustrated and described in different portions of the description and/or claims or in different embodiments.

LIST OF REFERENCE NUMERALS

(39) 1 Fiber structure 2 Spinneret 3 Eddy chamber 4 Intake of the eddy changer 5 Intake opening of the spindle 6 Spindle 7 Outside surface of the spindle 8 Inside wall of the eddy channel 9 Annular gap 10 Air jet 11 Longitudinal axis of the spindle 12 Draw-off channel 13 Front end of the spindle 14 Central axis of the air jets 15 Imaginary extension of the air jet 16 Imaginary extension of the central axis of the air jet 17 Spindle wall 18 Inside surface of the spindle 19 Tangent to the inside wall of the eddy chamber 20 Fiber guide element 21 Drawing device rollers 22 Belt 23 Sleeve 24 Bobbin 25 Draw-off roller 26 Outlet 27 Yarn 28 Air 29 Eddy chamber wall 30 Guide for fiber structure W Wall thickness of spindle d Inside diameter of air jet D Inside diameter of draw-off channel in a cylindrical region adjacent to the intake opening B Reference plane S Sectional plane