Textile machine for the production of roving and method for operating the same

Abstract

A method for operating a textile machine is provided to produce roving from a fiber bundle with a consolidating means, the roving having a protective twist. The produced roving is wound onto a tube with a winding device. During the winding process, the roving is guided a guide element arranged between the consolidating means and the tube, wherein the guide element exerts a decelerating effect on the roving. The decelerating effect is controlled during operation of the textile machine such that the decelerating effect is lower during a start procedure while the roving leaving the consolidating means is brought into contact with a tube or during a tube change while a wound tube is replaced by an empty tube than during a winding process that takes place between the start procedure and the tube change.

Claims

1. A method for operating a textile machine to produce roving, comprising: during roving production, producing a roving from a fiber bundle with a consolidating means, the roving having a protective twist; winding the produced roving with a winding device onto a tube; during the winding process, guiding the roving with a guide element arranged between the consolidating means and the tube, wherein the guide element exerts a decelerating effect on the roving; wherein the decelerating effect is controlled during operation of the textile machine such that the decelerating effect is lower during a start procedure while the roving leaving the consolidating means is brought into contact with a tube or during a tube change while a wound tube is replaced by an empty tube than during a winding process that takes place between the start procedure and the tube change.

2. The method according to claim 1, wherein the consolidating means is air spinning nozzle, wherein the roving having the protective twist is produced from the fiber bundle within the air spinning nozzle by means of a swirled air flow.

3. The method according to claim 1, wherein the decelerating effect is varied by decreasing or increasing a size of a contact area of the guide element over which the roving is in contact.

4. The method according to claim 3, wherein the roving is wrapped around the guide element over a wrapping angle (a), the decelerating effect varied by varying the wrapping angle (a) by winding or unwinding the roving on the guide element.

5. The method according to claim 4, wherein the wrapping angle () during the winding process is at least temporarily between 400 and 2000.

6. The method according to claim 4, wherein the wrapping angle (a) during the start procedure or the tube change is at least temporarily between 50 and 1000.

7. The method according to claim 1, wherein the decelerating effect causes a tension that acts on the section of the roving that is in contact with the guide element, the decelerating effect controlled such that an average magnitude of the tension during the winding process is at least two times higher than during the start procedure or during the tube change.

8. The method according to claim 1, wherein the decelerating effect is increased at the latest 10 seconds after the roving during the start procedure or during the tube change comes into contact with an empty tube.

9. The method according to claim 1, wherein the decelerating effect is increased while a 1st to 600th winding of the roving is being wound onto an empty tube.

10. The method according to claim 1, wherein the decelerating effect is reduced during the winding process at least 0.01 seconds prior to start of a pending tube change.

11. The method according to claim 1, wherein during the winding process, the roving is traversed between defined turning points by the guide element.

12. The method according to claim 1, wherein during the tube change the roving being produced by the consolidating means continues to be wound onto the tube until the roving comes into contact with an empty tube for the tube change.

13. The method according to claim 12, wherein the roving is guided continuously by the guide element during the tube change.

14. A textile machine for producing a roving, comprising: a consolidating means for producing a roving from a fiber bundle, the roving having a protective twist; a winding device configured to wind the produced roving onto a tube; and a controller that operates the textile machine such that the roving is produced in accordance with the method of claim 1.

15. The textile machine according to claim 14, wherein the consolidating means comprises an air spinning nozzle, wherein the roving having the protective twist is produced from the fiber bundle within the air spinning nozzle by means of a swirled air flow.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages of the invention are described in the following exemplary embodiments, in which:

(2) FIGS. 1 to 3 show part of a start procedure on a textile machine in the form of an air-jet spinning machine;

(3) FIG. 4 shows a plan view of part of a textile machine in the form of an air-jet spinning machine;

(4) FIG. 5 shows a side view of part of a textile machine in the form of an air-jet spinning machine;

(5) FIG. 6 shows the view of FIG. 4 with a changed wrapping angle;

(6) FIG. 7 shows a rear view of a guide element of a textile machine in the form of an air-jet spinning machine; and

(7) FIGS. 8 to 10 show the view of FIG. 4 with in each case a changed wrapping angle and a changed position of the guide element.

DETAILED DESCRIPTION

(8) 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.

(9) FIGS. 1 to 3 show a schematic view of part of a textile machine according to the invention in the form of an air-jet spinning machine serving as an example of such a textile machine, which serves to produce a roving 1, at different points in time during a start procedure. The air-jet spinning machine may, if necessary, comprise a drafting system 16 comprising a plurality of corresponding drafting system rollers 17 (only one of the drafting system rollers 17 has been provided with a reference sign for clarity reasons), to which there is fed a fiber bundle 3, for example in the form of a doubled-over draw frame sliver. The illustrated air-jet spinning machine also comprises in principle a consolidating means, spaced apart from the drafting system 16, in the form of an air spinning nozzle 2 having an internal vortex chamber (known from the prior art and therefore not shown) and a yarn forming element (likewise known from the prior art and therefore not shown). In the air spinning nozzle 2, the fiber bundle 3 or at least a portion of the fibers of the fiber bundle 3 is provided with a protective twist.

(10) The air-jet spinning machine may also comprise a draw-off unit 4 comprising preferably two draw-off rollers 18 for the roving 1 (the draw-off unit 4 is not absolutely necessary). A winding device 5 arranged downstream of the draw-off unit 4 is also usually present, which winding device in turn should comprise at least one tube drive 6 and in each case a tube holder which is connected to the tube drive 6 and is known in principle, by means of which a tube 7 can be fixed and can be set in a rotational movement by means of the tube drive 6.

(11) The winding device 5 may also comprise two or more two tube holders so that, besides a holder for a tube 7 that is currently being wound during operation of the air-jet spinning machine, one or more further holders for empty tubes 7 may be present. Once the first tube 7 has been wound, a tube change takes place, during which the wound tube 7 is replaced by an empty tube 7, so that the winding process 5 can ultimately be continued without any interruption in roving production.

(12) The air-jet spinning machine shown as an example of a textile machine according to the invention operates according to a special air spinning process. In order to form the roving 1, the fiber bundle 3 is guided in a transport direction T via an inlet opening (not shown) into the vortex chamber of the air spinning nozzle 2. There, it is given a protective twist, that is to say, at least a portion of the fibers of the fiber bundle 3 is grasped by a swirled air flow which is created by suitably placed air nozzles. A portion of the fibers is thereby pulled at least a little way out of the fiber bundle 3 and is wound around the tip of a yarn forming element which protrudes into the vortex chamber.

(13) Finally, the fibers of the fiber bundle 3 are drawn out of the vortex chamber via an inlet mouth of the yarn forming element and a draw-off channel which is arranged inside the yarn forming element and adjoins the inlet mouth. In doing so, the free fiber ends are finally also drawn on a helical trajectory in the direction of the inlet mouth and wrap as wrapping fibers around the centrally running core fibers, resulting in a roving 1 which has the desired protective twist.

(14) Due to the only partial twisting of the fibers, the roving 1 has a draftability which is essential for the further processing of the roving 1 in a downstream spinning machine, for example a ring spinning machine. Conventional air-jet spinning devices, on the other hand, give the fiber bundle 3 such a pronounced twist that the required drafting following yarn production is no longer possible. This is also desired in this case since conventional air-jet spinning machines are designed to produce a finished yarn, which is generally intended to be characterized by a high strength.

(15) Before a tube 7 can be wound with roving 1, a start procedure must take place, during which the roving 1 leaving the air spinning nozzle 2 is brought into contact with the tube 7. Part of a possible start procedure is shown in FIGS. 1 to 3.

(16) Firstly, a fiber bundle 3 is fed into the air spinning nozzle 2 by starting the drafting system 16. The above-described roving production, during which the fiber bundle 3 is given a protective twist, takes place in the air spinning nozzle 2. Finally, the roving 1 leaves the air spinning nozzle 2 via an exit opening (not shown in the figures) and is grasped by the air flow of a suction unit 8. The suction unit 8 preferably has a suction nozzle 13 with a suction opening 9, via which air and thus also the roving 1 leaving the air spinning nozzle 2 can be sucked up or sucked in. In this stage shown in FIG. 1, therefore, the roving 1 produced by the air spinning nozzle 2 leaves the air spinning nozzle 2 and is sucked into the suction unit 8 via the suction opening 9, wherein the delivery speed of the air spinning nozzle 2 preferably corresponds to the delivery speed prevailing after the start procedure or is only slightly lower than the speed.

(17) In general, it should be noted at this point that the entire start procedure preferably takes place without any break in roving production or roving delivery, that is to say, while the drafting system 16 is active, the air spinning nozzle 2 is active and, if present, the draw-off unit 4 is active (that is to say is drawing a roving 1 out of the air spinning nozzle 2), so that a particularly high efficiency of the illustrated air-jet spinning machine can be ensured.

(18) An illustrated controller 15 is also provided, which is operatively connected to the described elements of the air-jet spinning machine in order to carry out, inter alia, the start procedure. The controller 15 may be present for each spinning position of the air-jet spinning machine. It is also conceivable that one controller 15 is responsible for a plurality of spinning positions.

(19) In the next step (see FIG. 2), the suction unit 8 is moved (preferably the suction nozzle 13 is pivoted about a pivot axis 14) into a transfer position in which the suction opening 9 and thus also a section of the roving 1 (which is moreover still being delivered by the air spinning nozzle 2) are located in the region of the tube surface. Contact between the tube 7 and the roving 1 preferably does not yet exist at this stage.

(20) While the suction unit 8 is assuming its position shown in FIG. 2 (or shortly thereafter), the traversing unit 10 is moved into the position shown schematically in FIG. 3, in which the roving 1 is grasped and guided by the traversing unit 10. The traversing unit 10 thereby moves the roving 1 into the vicinity of the tube 7 or brings about direct contact between the tube 7 and the roving 1, so that the roving 1 (preferably under the effect of suitable rough surface sections of the tube 7) is grasped by the tube 7.

(21) At the same time or shortly thereafter, a cutting unit 11 is finally activated, which comprises for example a movable (preferably pivotable) cutting arm 12. The cutting unit 11 is thereby brought into contact with the roving 1, preferably with the section thereof that is located between the traversing unit 10 and the suction opening 9. At this moment, a local decelerating of the roving 1 occurs in the region which comes into contact with the cutting unit 11, so that the roving 1 finally tears between the tube 7 and the cutting unit 11 since it continues to be wound up by the rotating tube 7, that is to say has a tensile force applied to it. Due to the tearing of the roving 1, a section of the roving 1 on the suction unit side is obtained, which can be conveyed away via the suction unit 8. A roving section on the air spinning nozzle side is also obtained, which is already grasped by the tube 7 and extends between the air spinning nozzle 2 and the tube 7.

(22) By virtue of the further rotation of the tube 7, the roving 1 still being delivered by the air spinning nozzle 2 is continuously wound onto the tube 7, wherein the traversing unit 10, by virtue of a movement in the direction of the rotation axis 24 of the tube 7, ensures that the roving 1 is uniformly wound onto the tube 7. At this stage in which the cutting unit 11 and also the suction unit 8 have assumed their original positions, the air-jet spinning machine is finally in its normal mode following the start procedure, in which normal mode the tube 7 is wound with roving 1 until the desired bobbin size is achieved.

(23) According to the present invention, it is now provided that the roving 1 is guided by means of a guide element 23, wherein the guide element 23 is arranged between the air spinning nozzle 2 and the tube 7. Preferably, the guide element 23 is located between the tube 7 and the draw-off unit 4 that is arranged downstream of the air spinning nozzle 2 in the transport direction T, and is for example part of the traversing unit 10. Moreover, the roving 1 is decelerated by means of the guide element 23, that is to say the roving 1 is moved past the guide element 23 or a guide surface thereof in such a way that the friction between the guide element 23 and the roving 1 exerts a decelerating effect on the roving 1.

(24) The reason for the decelerating according to the invention is as follows: If the roving 1 were to be grasped directly by the rotating tube 7 after passing the air spinning nozzle 2 or a possible downstream draw-off unit 4, a tensile force would act on the roving 1 and would lead to the immediate tearing of the roving 1, since the latter has only a low tear resistance in comparison to a conventional yarn.

(25) If, on the other hand, the roving 1 is guided by means of the guide element 23 according to the invention before it is wound onto the tube 7, then the tensile force generated by the rotating tube 7 can be gradually reduced via the guide surface of the guide element 23 that is in contact with the roving 1 and via the associated friction between the roving 1 and the guide surface. In other words, the tensile force acting on the roving 1 is significantly lower between the air spinning nozzle 2 and the guide element 23 than between the guide element 23 and the tube 7. If, moreover, the guide element 23 bears against the tube 7 or the outer layer of the roving 1 that has already been wound thereon, then the roving 1 can take the high tensile force that is generated by the rotating tube 7, without tearing, since the fiber length of the roving 1 is generally longer than the spacing between the guide element 23 and the tube 7 or the outer roving layer.

(26) As a result, the roving 1 can ultimately be wound onto the tube 7 with a relatively high tension, without risk of tearing of the roving.

(27) One possible embodiment of the guide element 23 is shown firstly in FIGS. 4 and 5. For instance, it is conceivable that the traversing unit 10 comprises a traversing arm which can be moved back and forth parallel to the rotation axis 24 of the tube(s) 7 located in the winding device 5 and which at the same time represents the guide element 23. The guide element 23 preferably has a wrapping section 20, which is rod-shaped for example, and a front guide section 19 for the roving 1.

(28) FIG. 4 shows one possible course of the roving 1 coming from the air spinning nozzle 2 during the start procedure, which roving is still being sucked up by the suction unit 8 at this point in time. The roving 1 is guided in a guide groove 22 of the guide section 19 (cf. FIGS. 5 and 7) and wraps slightly around the wrapping section 20 so that only a low decelerating force acts on the roving 1. The fact that the decelerating effect is not too high is critical at this stage since the low tensile force brought about by the air flow of the suction unit 8, given too high a decelerating effect, would not be sufficient to draw the roving 1 over the guide surface of the guide element 23 (the guide surface is moreover that surface of the guide element 23 which is in each case directly in contact with the roving 1).

(29) Before the guide element 23 is pivoted in the direction of the tube 7, it may be advantageous to increase the decelerating effect, wherein this may take place for example by rotating a gripper 21. In so doing, the roving 1 is grasped and is wrapped further around the wrapping section 20. Such a screwing-in can be seen from a comparison of FIGS. 4 and 6 (which likewise shows that only the gripper 21 has moved, but not the guide section 19; to this end, a rotational decoupling (not shown) is provided between the gripper 21 and the wrapping section 20 or the guide section 19, so that the gripper 21 can be moved, preferably rotated, relative to the guide section 19 or to the wrapping section 20).

(30) FIG. 7 shows a view as seen in the direction of the arrow shown in FIG. 6. As can be seen from said FIG. 7, the decelerating effect exerted on the roving 1 by the guide element 23 is brought about on the one hand by the wrapping of the wrapping section 20. On the other hand, however, the decelerating effect is also increased by the wrapping of the gripper 21, since only the wrapping angle of a surface, but not the radius of curvature thereof, determines the extent of the friction force acting on the roving 1. The total wrapping angle is therefore composed of the wrapping angle 1 shown in FIG. 7 and the wrapping angle in the region of the gripper 21 (and possibly further wrapping angles of additional wrapped surface sections of the guide element 23). The actual wrapping angle in FIG. 7 is therefore higher than the denoted angle 1.

(31) FIG. 8 shows the stage in which the guide element 23 bears against the tube 7 and thus the roving 1 is brought into contact with the tube 7, as illustrated in FIG. 3 (as already mentioned, the guide element 23 is preferably part of the traversing unit 10 shown schematically in FIGS. 1 to 3). Following the contact between the tube 7 and the roving 1, the roving 1 is finally cut between the tube 7 and the suction nozzle 13. To this end, the air-jet spinning machine comprises for example a cutting unit 11 shown in FIGS. 1 to 3, having a cutting arm 12 which is mounted in a movable, preferably pivotable, manner. The cutting arm is pivoted into the course of the roving 1 and finally brings about a cutting of the roving 1 between the suction nozzle 13 and the tube 7. While one part of the roving 1 is sucked up by the suction nozzle 13, the other part coming from the air spinning nozzle 2 is wound onto the tube 7. FIG. 9 shows the start of the winding process, wherein the wrapping angle and thus also the decelerating effect on the roving 1 have been further increased in comparison to FIG. 8, wherein this has been achieved by a further rotation of the gripper 21.

(32) While the tube 7 continues to receive roving 1, the decelerating effect is finally increased to a final value which is maintained until the start of a following tube change so as to be able to wind the roving 1 onto the tube 7 under increased tension (see FIG. 10).

(33) Once a predefined degree of filling of the tube 7 has been reached, the decelerating effect is reduced again by reducing the wrapping angle , and the wound tube 7 is replaced by an empty tube 7 without interrupting the roving production. Once the roving 1 has entered into contact with the empty tube 7, the decelerating effect can be increased again by increasing the wrapping angle , until a new tube change is pending.

(34) The present invention is not limited to the exemplary embodiments that have been shown and described. Modifications within the scope of the claims are also possible, as is any combination of the described features, even if they are shown and described in different parts of the description or the claims or in different exemplary embodiments.

LIST OF REFERENCE SIGNS

(35) 1 roving 2 air spinning nozzle 3 fiber bundle 4 draw-off unit 5 winding device 6 tube drive 7 tube 8 suction unit 9 suction opening 10 traversing unit 11 cutting unit 12 cutting arm 13 suction nozzle 14 rotation axle of the suction nozzle 15 controller 16 drafting system 17 drafting system roller 18 draw-off roller 19 guide section 20 wrapping section 21 gripper 22 guide groove 23 guide element 24 rotation axle of the tube T transport direction wrapping angle