Abstract
A device for piecing a thread at a workstation of a textile machine includes a suction nozzle configured to pick up a thread end of the thread from a bobbin, the suction nozzle including an entry opening for the thread. A feeder unit is movable with respect to the suction nozzle and includes a cover element configured to close the entry opening in a first position (I) of the feeder unit and to unblock the entry opening in a second position (II) of the feeder unit. The cover element includes a thread-guiding element having an open contour.
Claims
1. A device for piecing a thread at a workstation of a textile machine, comprising: a suction nozzle mounted at the workstation and configured to pick up a thread end of the thread from a bobbin, the suction nozzle comprising an entry opening for the thread, a suction orifice, and a suction channel; a feeder unit movable with respect to the suction nozzle and comprising a cover element configured to close the entry opening in a first position (I) of the feeder unit and to unblock the entry opening in a second position (II) of the feeder unit, the feeder unit configured to form a loop from the thread end sucked into the suction nozzle; and the cover element comprising a thread-guiding element having an open contour, the thread-guiding element disposed within the suction channel in the first position (I) of the feeder unit and outside of the suction channel in the second position (II) of the feeder unit.
2. The device as in claim 1, wherein the cover element is formed of a plastic material.
3. The device as in claim 1, wherein at least one area of the suction nozzle surrounding the entry opening is curved in a longitudinal direction of the entry opening, and the cover element is also correspondingly curved in a longitudinal direction of the cover element.
4. The device as in claim 1, wherein the entry opening of the suction nozzle and the cover element each comprise opposed beveled edges that form a sealing surface.
5. The device as in claim 1, wherein the cover element comprises a sealing lip on a side thereof facing the thread-guiding element, the sealing lip formed of a flexible plastic material.
6. The device as in claim 5, wherein the cover element further comprises at least one holding element on the side thereof facing the thread-guiding element onto which the sealing lip is fitted.
7. The device as in claim 1, wherein the thread-guiding element is attached to the cover element off-center relative to a longitudinal direction of the cover element.
8. The device as in claim 1, wherein the thread-guiding element is made from a sheet-metal material.
9. The device as in claim 1, wherein the thread-guiding element comprises, at least in sections, a ceramic material.
10. The device as in claim 1, wherein the thread-guiding element is polished or comprises a coating.
11. The device as in claim 1, wherein the thread-guiding element comprises a first thread guide edge having a first fixing contour for a thread piece to be carried away and a second thread guide edge having a second fixing contour for the thread piece to be pieced.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Further advantages of the invention are described with reference to the exemplary embodiments represented in the following. Wherein:
(2) FIG. 1 shows a schematic, partially cut side view of a workstation of a textile machine during the regular operation;
(3) FIG. 2 shows the workstation from FIG. 1 after an interruption of the regular operation, wherein a thread has been suctioned into a suction nozzle;
(4) FIG. 3 shows the workstation of the textile machine from FIG. 1 during the formation of a thread loop;
(5) FIG. 4 shows a schematic cross-sectional representation of a device for piecing a thread end, according to a first embodiment;
(6) FIG. 5 shows a schematic cross-sectional representation of a device for piecing a thread end, according to a second embodiment;
(7) FIG. 6 shows a detailed view of a cover element comprising a sealing lip for sealing an entry opening of the suction nozzle; and
(8) FIG. 7 shows a schematic, truncated longitudinal representation of a device for piecing a thread end, according to a further, alternative embodiment.
DETAILED DESCRIPTION
(9) 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.
(10) In the following description of the figures and exemplary embodiments, the same reference signs are utilized for identical or comparable features in each of the various figures. The individual features or components are therefore described in detail only in the first mention thereof. Unless explained separately once more in the following exemplary embodiments and figures, the design and mode of operation of the features correspond to the design and the mode of operation of the features previously described with reference to another exemplary embodiment.
(11) FIG. 1 shows a sectional representation of a schematic side view of a workstation 2 of a textile machine 1. The textile machine 1 is designed as a spinning machine in this case and includes, as a thread-delivery device 3, a spinning device, in which a thread 4 is produced. The thread 4 is drawn off of the thread-delivery device 3 with the aid of two delivery rollers 5 and is delivered to a winding device 6, where the thread 4 is wound onto a bobbin 7. In deviation from the representation shown, it would also be possible for the textile machine 1 to be designed not as a spinning machine, but rather as a winder. In this case, the workstation 2 comprises, as a thread-delivery device 3, a delivery bobbin, from which the thread 4 is drawn off and is wound onto a bobbin 7 as described above.
(12) Moreover, the workstation 2 of the textile machine 1 shown here is designed as an autonomous workstation 2 which is capable of automatically re-piecing a thread end 4a (see FIG. 2) after an interruption in production. For this purpose, the thread end 4a is returned into the spinning device, where the thread end 4a is reconnected to further fibers to be incorporated into the thread. In the case of a winder, a thread end 4a coming from the bobbin 7 is connected to a thread end (not shown) of the delivery bobbin. For this purpose, the workstation 2 shown here is provided with a device 16 for piecing a thread 4. The device 16 for piecing the thread 4 includes a suction nozzle 8 in this case, with the aid of which a thread end 4a (see FIG. 2) of the thread 4 traveling onto the bobbin 7 is sought and can be suctioned into a suction duct 9 of the suction nozzle 8. The suction nozzle 8 is connected to a vacuum duct 10 in a known way in order to apply a vacuum to the suction duct 9. The suction nozzle 8 includes a suction orifice 11 for suctioning in the thread end 4a. Moreover, the device 16 comprises a feeder unit 13, with the aid of which the thread end 4a picked up by the suction nozzle can be delivered, while forming a thread loop (see FIG. 3), to a piecing unit 17 or to another handling unit of the workstation 2 or can be delivered directly to the thread-delivery device 3. For this purpose, the feeder unit 13 includes a movably, in particular pivotably, mounted lever 24 which is provided with a thread-guiding element 15, in which the thread end 4a can be picked up by the suction nozzle 8. The movement of the feeder unit 13 is symbolized in this case by the arrow and the dashed-lined, second representation of the feeder unit 13.
(13) According to the present representation, the suction nozzle 8 is fixedly situated at the workstation 2, wherein the thread 4 extends through the suction nozzle 8 during the regular operation of the workstation 2. In this case, the thread 4 enters the suction nozzle 8 through an entry opening 12 and exits the suction nozzle 8 through the suction orifice 11. The feeder unit 13 comprises a cover element 14 for closing the entry opening 12 of the suction nozzle 8. The feeder unit 13 can be displaced between a first position I (see FIG. 2) for taking the thread end 4a from the suction nozzle 8 and a second position II for forming the thread loop and for transferring the thread end 4a. In the second position II of the feeder unit 13, which is shown here, the thread-guiding element 15 is located outside the suction duct 9 of the suction nozzle 8 and the cover element 14 unblocks the entry opening 12 of the suction nozzle 8, and so the thread 4 can extend through the suction nozzle 8 during production.
(14) If an interruption in production now occurs, for example, due to a thread break or a clearer cut, a thread end 4a (see FIG. 2) is formed, which travels onto the bobbin 7 since the bobbin 7 is still rotating. Therefore, it is necessary to search for the thread end 4a traveling onto the bobbin 7 with the aid of the suction nozzle 8 and to suction the thread end 4a into the suction nozzle 8.
(15) FIG. 2 shows the workstation 2 of the textile machine 1 in a situation in which, after an interruption in production, the thread end 4a has just been suctioned into the suction nozzle 8. In order to search for the thread end 4a on the bobbin 7, the feeder unit 13 is initially moved into its first position I, being pivoted in this case. In this position I, the thread-guiding element 15 is located within the suction duct 9 of the suction nozzle 8 and the cover element 14 closes the entry opening 12 of the suction nozzle 8. Vacuum can now be applied to the suction nozzle 8 via the vacuum duct 10 and the suction duct 9 can search for the thread end 4a on the surface of the bobbin 7. When the thread end 4a is suctioned in, the thread end 4a enters not only the suction duct 9 of the suction nozzle 8, but also, simultaneously, the thread-guiding element 15 of the feeder unit 13. The thread end 4a is now held within the suction nozzle 8 via the suction draught. It is necessary to reliably seal the entry opening 12 with the aid of the cover element 14 while vacuum is being applied to the suction nozzle 8 in order to not adversely affect the effect of the vacuum in the suction nozzle 8 and, in addition, to reduce the energy consumption of the textile machine 1.
(16) Finally, FIG. 3 shows yet another situation of the workstation 2 of the textile machine 1, in which the suctioned-in thread end 4a is delivered to the piecing unit 17, in this case, while forming a thread loop. For this purpose, the feeder unit 13 is moved from its first position I (see FIG. 2) back into its second position II, in which the cover element 14 unblocks the entry opening 12 and the thread-guiding element 15 is located outside the suction duct 9. By drawing the thread loop open, the original thread end 4a is now transformed into a thread piece 4b to be pieced and a thread piece 4c to be carried away. The two thread pieces 4b and 4c can now be separated, for example, with the aid of the piecing unit 17, and so the thread piece 4b can be delivered to the thread-delivery device 3 for piecing and the thread piece 4c can be suctioned into the vacuum duct and discarded thereby.
(17) In order to now facilitate the sealing of the entry opening 12 with the aid of the cover element 14 during the suctioning-in of the thread end 4a, the thread-guiding element 15 is no longer designed as a closed contour in the form of an eyelet, as was the case previously, but rather as an open contour. This is represented in FIG. 4 which shows a schematic cross-sectional representation of the device 16 including the suction nozzle 8 including the suction duct 9 as well as the feeder unit 13. The feeder unit 13 is represented in its first position I in this case, in which the cover element 14 closes the entry opening 12 of the suction nozzle 8 and the thread-guiding element 15 is located in the suction duct 9. The thread-guiding element 15 is situated off-center in this case, relative to the longitudinal direction of the cover element 14. In this case, the thread-guiding element 15 is situated in the area of one longitudinal end 14a of the cover element 14. As a result, the cover element 14 can flexibly adapt to the entry opening 12, in particular, at the other longitudinal end 14a which is positioned opposite the first longitudinal end 14a at which the thread-guiding element 15 is situated.
(18) Due to the fact that there is a vacuum within the suction duct 9 at least during the search for the thread, it is also possible for the free longitudinal end 14a to be suctioned onto the entry opening 12 of the suction nozzle 8 via the vacuum, which supports the sealing effect of the cover element 14. Moreover, FIG. 4 shows a first thread guide edge 20, along which the thread piece 4c to be carried away glides during the drawing-open of the thread loop (see FIG. 3), until the thread piece 4c is finally fixed at a first fixing contour 21. In addition, the thread piece 4b to be pieced glides along a second thread guide edge 22 during the further drawing-open of the thread loop, until the thread piece 4b is finally fixed at a second fixing contour 23. After the thread loop has been drawn completely open, the thread piece 4b to be pieced and the thread piece 4c to be carried away are therefore separated from each other by the thread-guiding element 15 and can therefore be cut in two, as described above.
(19) FIG. 5 shows another embodiment of a device 16 for piecing a thread end 4a, in which the cover element 14 is curved in its longitudinal direction. In the case of the suction nozzle 8 as well, at least the area of the suction nozzle 8 surrounding the entry opening 12 is curved in its longitudinal direction. The longitudinal direction corresponds to the greatest dimension of the slot-shaped entry opening 12 in this case. The sealing of the entry opening 12 by the cover element 14 is facilitated as a result. Moreover, a sealing lip 18 is shown in FIG. 5, which has been installed on the cover element 14 and also facilitates the sealing of the entry opening 12. The cover element 14 and the sealing lip 18 are particularly resilient, in particular, when the cover element 14 as well as the sealing lip 18 are made from a plastic material, and so an improved seal can be achieved solely by way of the cover element 14, including the sealing lip 18, being drawn in via the vacuum. An increased contact pressure onto the cover element 14, for example, by way of a drive of the feeder unit 13, is not necessary in this case. The sealing lip 18 is situated, in this case, on the side of the cover element 14 facing the thread-guiding element 15 and, therefore, on the inside of the cover element 14 and is connected to the suction duct 9 and, therefore, also to the vacuum prevailing therein during the suctioning. By contrast, the side of the cover element 14 facing away from the thread-guiding element 15 faces the outside of the suction nozzle 8.
(20) In order to enable the sealing lip 18 to be attached to the cover element 14, the cover element 14 comprises several holding elements 19 in this case, onto which the sealing lip 18 has been fitted. The holding elements 19 are spaced from each other in this case, and so the sealing lip 18 is not connected to the cover element 14 over the entire surface thereof. The sealing lip 18 can therefore move with respect to the cover element 14, which facilitates the suctioning-in of the sealing lip 18 by the vacuum prevailing within the suction duct 9.
(21) FIG. 6 shows a top view of the inner side or the side of the cover element 14 facing the thread-guiding element 15, onto which the sealing lip 18 is installed. According to the present representation, the holding elements 19 are situated in two rows, namely above and below the thread-guiding element 15 in this case. It would also be conceivable to provide only one row of holding elements 19 which would then be situated to the left and the right of the thread-guiding element 15 relative to the representation in FIG. 6. Moreover, it would also be conceivable, of course, to provide a total of only 2 or 3 holding elements at different points of the cover element 14.
(22) FIG. 7 shows a schematic, truncated longitudinal representation of a device 16 for piecing a thread end 4a according to a further, alternative embodiment. In this case, the entry opening 12 of the suction nozzle 8 comprises two beveled edges which are positioned opposite each other and extend in the longitudinal direction of the entry opening 12. The beveled edges each form a sealing surface 25 for the cover element 14. With respect to the cover element 14 as well, the two edges extending in the longitudinal direction of the entry opening 12 are beveled and form sealing surfaces 25. Preferably, all the edges delimiting the entry opening 12 and all the edges of the cover element 14 are beveled or are provided with a circumferential, beveled edge in order to achieve a particularly good seal. It is understood that the edges of the cover element 14 are beveled in a manner corresponding to the edges of the entry opening 12 in each case, and so the entry opening 12 is designed as a positive shape and the cover element 14 is correspondingly designed as a negative shape.
(23) The invention is not limited to the exemplary embodiments which have been represented. Modifications and combinations within the scope of the claims are also covered by the invention, even if they are not represented in the exemplary embodiments or their individual features are represented in various exemplary embodiments.
LIST OF REFERENCE SIGNS
(24) 1 textile machine 2 workstation 3 thread-delivery device 4 thread 4a thread end 4b thread piece to be pieced 4c thread piece to be carried away 5 delivery device 6 winding device 7 bobbin 8 suction nozzle 9 suction duct 10 vacuum duct 11 suction orifice 12 entry opening 13 feeder unit 14 cover element 14a longitudinal end of the cover element 15 thread-guiding element 16 device for piecing the thread 17 piecing unit 18 sealing lip 19 holding element 20 first thread guide edge 21 first fixing contour 22 second thread guide edge 23 second fixing contour 24 lever 25 sealing surface I first position of the feeder unit II second position of the feeder unit
