EP0226582B1 - Process and device for thread joining on an open-end spinning device - Google Patents

Abstract

In preparation for the fibre-joining process an underpressure is brought into effect outside the fibre transport path on the circumference of an opening cylinder (11), the underpressure being greater than the spinning underpressure which is effective at the opening (130) of the feed channel (13) for the fibre collection surface (33). In this way, the fibre flow over the opening (130) is diverted away and sucked up. At the start of the actual fibre joining process this underpressure is suppressed, so that the fibre flow is led to the fibre collector surface (33). To control the fibre flow an underpressure source (5) can be connected to the suction opening (52) by a switch-over device (64) and an underpressure line (51).

Description

The present invention relates to a method for spinning on an open-end spinning device with a sliver feed device and an opening roller arranged in a housing, from which the fibers are fed in an air flow generated by the spinning negative pressure through a feed channel to a fiber collecting surface and in which a thread end is spun onto the spinning device Fiber collection surface is returned, from which the previously returned thread is then pulled off again with continuous incorporation of fibers, the feed device being switched on to remove the fibers unsuitable for piecing, and the fiber stream being fed via a feed channel mouth to a suction device arranged behind the feed channel mouth in the opening roller housing and only then at the beginning of the actual piecing process, the fiber stream is fed to the fiber collecting surface, and a device for carrying out this method.

In the event of a thread break or after the spinning process has come to a standstill in another way, the feed device is shut down immediately in order to prevent unnecessary fiber supply which clogs and damages the spinning device. However, the opening roller generally continues to run, since stopping it separately, in particular for each spinning station, not only requires a great deal of technical effort, but also takes a long time to start up and run down. The result of this is that the fiber beard protruding from the shutdown feed device into the area of the opening roller is completely removed. In front When restarting, these fiber remnants must first be removed from the fiber collection surface because these shortened and thus damaged fibers usually do not guarantee that the spinning process will continue properly (CH-PS 526.646).

It is therefore known from the practice of manual piecing and breaking of the thread that the spinner first starts the feed device for a short time, then cleans the spinning device and only then attaches the thread. This so-called starter removes the damaged part of the beard with the shortened fibers. The subsequent stoppage of the feed device during cleaning in turn damages a considerable part of the fibers, but enough fibers remain in the fiber beard for successful piecing. Due to the standstill of the feed device, which is dependent on the time for cleaning, approximately the same piecing conditions were always created with respect to the fiber beard, so that the success rate in threading was considerably improved even at high rotor speeds and difficult materials.

Based on the knowledge that each standstill of the feed device causes a certain damage to the fiber beard, depending on the length of the standstill, it has also been proposed to deflect the fiber stream on its way to the fiber collection surface while the feed device is running and to lead it past the fiber collection surface into a suction device . For this purpose, suction openings (GB-PS 1.170.869) or compressed air openings (DE-A 3.104.444) are provided in the feed channel. Due to the uninterrupted fiber feeding and dissolving process, undamaged fibers are fed to the fiber collecting surface exactly at a desired time, but through such openings in the very sensitive fiber transport path between the opening roller and the fiber collecting surface, the spinning process is disrupted. Therefore none of these suggestions has gained practical importance.

According to DE-OS 31 18 382, switching is carried out by two sliders. The fiber channel is totally shut off by the first slide, so that there is no suction at all in the rotor. The other slide also blocks the rotor housing, so that no more suction air flow gets into the rotor from the suction source. However, this means that the thread end can neither be returned nor held in the rotor. This is a major disadvantage.

It is also known from DE-PS 3.104.444 to guide the fiber stream solely through appropriate control of the negative pressure in the suction through the feed channel mouth into the suction or back into the spinning rotor. In this case, the suction air flow in the spinning rotor is deliberately not switched off, because this is the only way to ensure that the thread is retained by the negative pressure that continues to exist in the rotor housing. However, it has been shown that the fiber flow cannot be controlled in this way, since the fibers are already at the first opening in the peripheral wall, i.e. at the mouth of the feed channel, leave the interior of the opening roller housing. This type of fiber flow control has therefore not been able to establish itself in practice.

It is an object of the present invention to provide a method and a device for spinning on an open-end spinning device, which enable a perfect and safe spinning in an economical manner without impairing the subsequent spinning process.

This object is achieved according to the invention in that for the introduction of the thread end into the spinning device the spinning vacuum is effective, that the thread end is only inserted into the spinning device to such an extent that it does not touch the fiber collecting surface, and that the spinning vacuum is then switched off is while the suction arranged in the opening roller housing is effective, so that when the feed device is switched on, the fiber stream is led over the feed channel mouth and sucked off until the end of the thread is returned to the fiber collecting surface at the start of the actual piecing process, this suction is switched off again and the spinning vacuum is switched on again , so that the fiber stream is fed to the fiber collecting surface. Because the spinning vacuum initially remains switched on, the thread end is certainly stretched and inserted into the thread take-off tube and brought into the ready position. By subsequently switching off the spinning vacuum, there is a drop in the vacuum in the draw-off tube, but the suction of the suction arranged in the opening roller housing keeps the thread end stretched in this ready position, so that there are no difficulties when piecing. The rotor running again for attachment additionally generates a flow in the thread draw-off tube that supports this stretching. It is therefore important that the spinning vacuum between the vacuum source and the rotor is switched off so that the suction arranged in the opening roller housing can act in the rotor area.

The spinning vacuum is advantageously switched off and on again between a suction air source and the fiber collecting surface.

Appropriately, in order to achieve unobtrusive piecing with high strength, the procedure is such that, in order to remove the fibers that are undesirable for spinning, the fiber stream is first led over the mouth of the feed channel, that the fiber stream is then briefly fed to the fiber collecting surface, then again led over the mouth of the feed channel, and only then is fed back to the fiber collecting surface after the thread end has reached the fiber collecting surface and the thread has started to be drawn off.

If the opening roller is followed by a fiber transport roller, it can alternatively be provided that, instead of the circumference of the opening roller, a negative pressure outside the fiber transport path relative to the periphery of a fiber transport roller connected downstream of the opening roller is brought into effect to remove the fibers that are undesirable for spinning.

To carry out the method, according to the invention, in the case of an open-end spinning device with a sliver feed device, an opening roller housing with an opening roller, a fiber collecting surface rotating in a housing, a feed channel leading from the opening roller housing to the fiber collecting surface, a vacuum source for generating the vacuum underpressure and a suction opening in the peripheral wall of the opening roller housing a switching device between the vacuum source and the fiber collecting surface for switching the spinning vacuum on and off and a switching device for switching the vacuum on and off are provided at the suction opening. As a result, the air streams for removing the fibers from the roller housing so that the fibers do not get into the spinning unit or for feeding the fibers into the spinning unit can be adapted exactly to the requirements of piecing.

For exact control of the thread during the piecing process, according to a preferred development of the device according to the invention, a thread return device for returning the thread end to a standby position within the thread take-off tube, a discharge device for releasing the thread end for its return delivery to the fiber collecting surface and a control device for controlling the piecing process and of the switching devices provided. The switching devices are expediently designed as part of a switching device by means of which the negative pressure source can alternately be connected to the fiber collecting surface as spinning negative pressure or to the suction opening for suctioning off the fibers.

Yarn and fiber residues must not accumulate in the switching device during suction. For this reason, the fiber stream in the switching device should not be deflected. For this purpose, according to a further embodiment, the switching device according to the invention has two control bores, one of which can be brought into alignment with a first vacuum line to the fiber collecting surface and the other can be brought into alignment with the second vacuum line to the suction opening.

In order not to impair the functional reliability of the switching process, it should be avoided that yarn and fiber residues can be trapped in the air control device. For this purpose it can be provided according to the invention that the stationary edges as well as the movable edges of the switching device that can be brought into alignment with them are designed as cutting devices.

The switching of the vacuum ratios can in principle be carried out in any customary manner, for example with the aid of electromechanical or hydro- or pneumo-mechanical means. According to a particularly simple embodiment of the subject matter of the invention, the switchover is carried out mechanically, the switchover device being actuated in one direction of movement by a control drive, while a spring element is provided for the resetting.

If a maintenance trolley is provided, which can optionally be delivered to any number of spinning positions, then according to the invention a second vacuum source is provided on this maintenance trolley, the switching device being used to alternately switch on the vacuum source to generate the spinning vacuum and the vacuum source to remove the fibers which are undesirable for piecing .

It is common nowadays to control the piecing from a maintenance car which can be moved along several spinning devices. In such a case, the switching device can be controlled from the maintenance car.

In order to make additional drive means for the switching device superfluous, the switching device can advantageously be controlled by the connecting movement of a suction air line emanating from the maintenance vehicle to the switching device and / or by the negative pressure in this suction line.

The device for controlling the vacuum can be different, e.g. be designed as a fan controllable from the maintenance device; however, it advantageously contains a valve, in particular a check valve.

If the opening roller is followed by a fiber transport roller, then according to the invention the suction opening can be arranged in the peripheral wall surrounding the opening roller instead of in the peripheral wall surrounding the opening roller.

The present invention makes it possible, with the aid of a simple device, to control the fiber feed into the spinning chamber in such a way that only perfect fibers enter the spinning chamber for piecing, since all control and switching devices for the fiber stream outside the critical fiber transport path between the opening roller and the fiber collecting surface are arranged so that an effective deflection of the fiber flow past the fiber collecting surface into a suction for piecing is achieved without affecting the subsequent spinning process. The invention even enables quantitative control of the fiber flow, so that not only the piecing takes place, but also the appearance of the piecing is improved to a considerable extent without additional devices for the controlled drive of the feed device being required for this.

In addition, a safe return of the thread end in the open-end spinning device and a secure holding of the returned thread end is guaranteed. In this way, an optimal success rate for piecing is guaranteed.

Figur 1

im schematischen Querschnitt eine erfindungsgemäß ausgebildete Offenend-Spinneinrichtung;

Figur 2

in der Draufsicht eine an der Außenseite eines Unterdruckkanals angeordnete Schaltvorrichtung gemäß der Erfindung;

Figur 3

im Querschnitt eine andere Ausbildung einer erfindungsgemäßen Schaltvorrichtung;

Figur 4

im Schnitt eine Abwandlung einer Offenend-Spinnvorrichtung gemäß der Erfindung;

Figur 5

im schematischen Querschnitt eine alternative Ausgestaltung einer erfindungsgemäß ausgebildeten Offenend-Spinneinrichtung;

Figur 6

in schematischer Seitenansicht eine Offenend-Spinnvorrichtung mit abgeänderter Schaltvorrichtung.

Further details are explained in more detail with reference to exemplary embodiments shown in the drawings. Show it:

Figure 1

in schematic cross section an open-end spinning device designed according to the invention;

Figure 2

in plan view a switching device arranged on the outside of a vacuum channel according to the invention;

Figure 3

in cross section another embodiment of a switching device according to the invention;

Figure 4

in section a modification of an open-end spinning device according to the invention;

Figure 5

in schematic cross section an alternative embodiment of an open-end spinning device designed according to the invention;

Figure 6

a schematic side view of an open-end spinning device with a modified switching device.

The invention is first explained below with reference to FIG. 1, which shows a spinning position of a rotor spinning machine, but the invention can also be used with other open-end spinning machines, e.g. Use friction spinning machines with advantage.

Each spinning station of the rotor spinning machine shown has a disintegration device 1 with an opening roller 11 arranged in an opening roller housing 10. For feeding a sliver 40, the opening device 1 is assigned a feed device 2, which in the exemplary embodiment shown consists of a driven one Feed roller 20 and a feed trough 21, which cooperates elastically with the feed roller 20. In the exemplary embodiment shown, a dirt separating opening 12 is also provided in the peripheral wall 101 of the opening roller housing 10 surrounding the opening roller 11. Furthermore, the opening 130 of a feed channel 13 leading to the open-end spinning device 3 is provided in the peripheral wall 101 of the opening roller housing 10.

The open-end spinning device has a spinning unit designed as a spinning rotor 30, which is enclosed by a housing 31. Coaxial to the spinning rotor 30, a thread draw-off tube 32 opens into the housing 31, through which a thread 4 can be drawn out of the spinning rotor 30. For this purpose, a pair of take-off rollers 41, 42 is provided. The thread 4 is wound on a spool 44 driven by a winding roller 43. To release a piecing reserve previously formed, a discharge magnet 45 is provided in the vicinity of the thread path between the take-off rollers 41, 42 and the winding roller 43.

A vacuum line 50 is connected to the housing 31 in order to generate the necessary spinning vacuum and is connected to a vacuum source 5. Since air can be sucked into the housing 31 through the thread take-off tube 32, the spinning vacuum acting in the housing 31 is only effective to a limited extent via the feed channel 13 also at its mouth 130. In addition to this first vacuum line 50, a second vacuum line 51 connected to the open-end spinning device 3 is provided. This second vacuum line 51 ends in a suction opening 52, which - as seen in the fiber transport direction (arrow 46) - is provided between the mouth 130 of the feed channel 13 and the delivery device 2 outside the fiber transport path in the peripheral wall 101 of the opening roller housing 10. This second vacuum line 51 is also connected to the vacuum source 5 via a switching device 64. In the exemplary embodiment shown, this switching device is 64 designed as a rotary valve. With the help of the switching device 64, the first or the second vacuum line 50, 51 can alternately be connected to the vacuum source 5, which in this way is alternately assigned to the fiber collecting surface 33 of the spinning rotor 30 as spinning vacuum or the suction opening 52 for suctioning the fibers 47. For this purpose, the switching device 64 is connected to a drive device 60, which is controlled by a control device 7. The position of the switching device 64 shown with a solid line in FIG. 1 is the spinning position during which the spinning vacuum is generated in the spinning rotor 30, and the position indicated by dashed lines is the fiber removal position in which the vacuum is present at the suction opening 52. Depending on the position which the switching device 64 occupies, the fibers 47 are thus guided into the feed channel 13 or into the suction opening 52.

Of course, a filter, not shown, is provided in the vacuum line 51 at a suitable point, with which the extracted fibers 47 are collected.

The sliver 40 to be spun is fed to the opening device 1 with the aid of the feed device 2 and is broken up into individual fibers 47 by the opening roller 11. Through the opening roller 11, which effects the fiber transport from the feed device 2 to the feed channel 13, dirt constituents contained in the fiber material are thrown out through the dirt separation opening 12. The fibers 47, on the other hand, enter the spinning rotor 30 and are deposited there on the fiber collecting surface 33, where the fibers 47 are bound into the end of the thread 4. This thread 4 is drawn off from the spinning rotor 30 by the take-off rollers 41, 42 and wound on the spool 44. During this normal spinning process, the switching device 64 assumes its spinning position, in which, via the first vacuum line 50, the one generated by the vacuum source 5 Spinning vacuum is present on the housing 31 and to a reduced extent on the mouth 130 and the connection of the second vacuum line 51 to the vacuum source 5 is interrupted.

If a yarn breakage now occurs, the spinning process is interrupted in a known manner via a thread monitor, not shown, and the spinning station is switched off. For this purpose, the supply of the sliver 40 to the opening roller 11 is stopped by stopping the delivery device 2. However, the housing 31 remains in connection with the vacuum source 5. The spinning rotor 30 is then braked. At the same time, the fibers 47 still remaining in the spinning rotor 30 and the end of the broken thread 4 are detached from the thread-forming region 33 of the spinning rotor 30 by introducing a mechanical or pneumatic cleaning agent and suctioned off from there.

Already during this cleaning phase or even thereafter, the thread 4 is sought on the bobbin 44, drawn off from it, shortened to a defined length, brought to the mouth of the thread take-off tube 32 via the armature of the ejection magnet 45, and then with the aid of the also in the thread take-off tube 32 effective spinning negative pressure is introduced into the spinning rotor 30, but without touching its fiber collecting surface 33.

In order to prevent further fibers 47 from getting onto the fiber collecting surface 33 of the spinning rotor 30 after the spinning rotor 30 has been cleaned after the feed device 2 has been switched on again, the changeover device 64 is then brought into its fiber removal position in preparation for the piecing process. The feed device 2 is then switched on again. The fiber stream is now sucked out of the opening roller housing 10 through the suction opening 52. Since the spinning rotor 30 is stopped and the spinning vacuum on the housing 31 of the open-end spinning device 3 is switched off, so that the effect of the spinning vacuum is canceled, that at the suction opening is sufficient 52 suction air flow brought into effect in order to convey the fibers 47 against the effect of the centrifugal force generated by the rotating opening roller 11 via the mouth 130 of the feed channel 13 to the suction opening 52. In this way it is ensured that the fibers 47, which were milled off in the time from the shutdown phase by the continuous opening roller 11 and thereby shortened, cannot get into the spinning rotor 30 and reduce the strength of the piecing.

During the return delivery of the thread 4 before the mouth of the thread take-off tube 32, the thread end acquires a shape which is advantageous for piecing in a known manner. The switching device 64 is reversed again and brought into its spinning position so that the vacuum is switched off at the suction opening 52 and switched on in the spinning rotor 30 and at the mouth 130 of the feed channel 13.

By dropping the thread 4 from the ejection magnet 45, the thread 4 is now returned to the fiber collecting surface 33 due to the negative pressure now acting in the spinning rotor 30. The thread end comes into contact with the fibers 47 located on the fiber collecting surface 33, which in the case of the spinning rotor shown form a fiber ring. The thread 4 is then withdrawn from the spinning rotor 30 with the constant inclusion of the continuously fed fibers 47 and wound on the spool 44.

The switching operations of the switching device 64 are carried out with the aid of a drive device 60, which receives its control commands from a control device 7. In addition to the switching device 64, this control device 7 generally controls other processes besides piecing and thread break repair, such as, for example, changing bobbins, etc.

Another device will now be described with reference to FIGS. 1 and 2.

FIG. 2 shows the underside of a suction channel 53 which is connected to the vacuum source 5 (FIG. 1) and which - as is customary in open-end spinning machines - can be arranged via a large number of spinning stations arranged next to one another, e.g. Rotor spinning positions, extends. For each open-end spinning device 3, a switching device 6 is provided on this suction channel 53, which has a web 54 and 55 on its underside on its underside. Two actuating elements 61 and 62 are mounted in the web 54 facing the operating side (on the right in FIG. 2). The adjusting element 61 has an elongated hole 610, with the aid of which the vacuum line 50 or 51 can be connected to openings provided in alignment in the underside of the suction channel 53. The actuating element 61 is sealingly guided between the underside of the suction channel 53 and a sealing strip 56 which connects the two webs 54 and 55 to one another. The elongated hole 610 has a minimum size which corresponds to that of the cross sections of the vacuum lines 50 and 51, but can also have a greater length, as will be explained below.

At its end facing the operating side of the spinning machine 36 (on the right in FIG. 2), the actuating element 61 has an enlarged actuating button 611. One end of a spring element 612, the other end of which is supported on the web 54, is supported on this actuating button 611. The control element 61 has at its other end a stop 613 which secures the released control element 61 in its spinning position, in which the vacuum line 50 is connected to the suction channel 53.

The actuating element 61 has on its longitudinal side a latch 614, behind which a pawl 63 can snap. The pawl 63 is pivotally mounted about an axis 58 provided in the web 55 and is elastically loaded by a spring element 630. The other end of the spring element 630 is supported on a web 57 which connects the two webs 54 and 55 to one another.

The pawl 63 has at its end facing the web 54 a ramp-like slope 631, on which the bevelled end 620 of the actuating element 62 can run. The end of the actuating element 62 facing away from this bevelled end 620 has an enlarged actuating button 621. A spring element 622 is supported between this actuating button 621 and the web 54, so that the actuating element 62 is acted on in the direction of the operating side (on the right in FIG. 2) of the machine . In order to limit the movement caused thereby, the actuating element 62 carries a stop 623 between the web 54 and the bevelled end 620.

The above-mentioned control device 7, which controls the entire piecing process, etc., is arranged on a maintenance carriage 70, which can be moved along the operating side of the spinning machine 36 and can thus optionally operate any desired spinning position of a multiplicity of such spinning positions. This control device 7 is connected in a suitable manner in terms of control to drive bolts 71 and 72, which together with the actuation buttons 611 and 621 form a drive device 60 for the switching device 6. The drive bolts 71 and 72 can each be part of an armature of an electromagnet, for example. If the drive bolts are to be driven gradually, that is to say very gradually or during their movement phase at changing speeds, then a drive with the aid of a stepping motor or the like is also possible.

FIG. 2 shows the switching device 6 in its fiber removal position, since the elongated hole 610 opens the connection between the suction channel 53 and the vacuum line 51. In this position, the actuating element 61 is secured by the pawl 63, which is locked behind the latch 614. If the switching device 6 is now to be brought into its spinning position, the control device 7 of the maintenance device 70 actuates the actuation button 621 with the aid of the drive bolt 72 - or, if desired, also by hand. When the actuating element 62 moves, the return spring 622 is tensioned. The actuating element 62 finally comes with its bevelled end 620 to bear against the bevel 631 of the pawl 63 and pivots it against the action of the return spring 630. As a result, the pawl 63 releases the detent 614, and the actuating element 61 can by the now relaxing return spring 612 return to its basic position, which is shown in broken lines in FIG. This position is defined by the stop 613.

After the actuation button 621 has been released, the actuating element 62 also returns through the relaxing return spring 622 to the starting position shown, in which the stop 623 bears against the web 54. The pawl 63, which is now released again, is now brought back into contact with the actuating element 61 by the return spring 630.

If the switching device 6 is to be brought back into the fiber removal position at a later time, this is done by actuating the actuating button 611 with the aid of the drive bolt 71 or by hand. The actuating element 61 reaches the position shown, in which the return spring 612 is preloaded, in which it is secured by the pawl 63 engaging behind the catch 614.

In the switching device 6 shown in FIG. 2, the elongated hole 610 has a larger opening than the cross section of the vacuum line 50 or 51, so that in an intermediate position the elongated hole 610 connects the suction channel 53 both to the first vacuum line 50 and to the second Vacuum line 51 partially released and thus both the fiber collecting surface 33 and the suction opening 52 are simultaneously subjected to negative pressure. This ensures that the fibers 47 are not suddenly left alone during the switchover, but are always in a suction air flow.

The switching device 6 described with reference to FIG. 2 allows both the actuation from a maintenance trolley 70 and the manual actuation, which is very simple due to the possibility of locking the actuating element 61.

A simplified switching device 8, which is particularly suitable for actuating a maintenance car 70, will now be described with the aid of FIG. 3. An actuator 81 is slidably mounted in a housing 80. The housing 80 is closed on both sides by a cover 82 and 83, respectively. Between the cover 82 and the control element 81 there is a spring element 84, which thus acts on the control element 81 in the direction of the cover 83. The cover 83 has a central bore 830 through which an adjusting bolt 810 of the actuating element 81 extends.

The actuating element 81 has two control bores 811 and 812, of which the control bore 811 connects two pipe sockets 500 and 501 to one another when the spring element 84 is relaxed. These pipe sockets 500 and 501 serve to connect the first vacuum line 50 to the changeover device 8. The second control bore 812 of the control element 81 connects two pipe sockets 510 and 511 to one another in its other end position, which serve to connect the second vacuum line 51 to the switching device 8.

In the spinning position, the actuating element 81 is in the position shown, in which the control bore 811 is in alignment with the vacuum line 50 to the fiber collecting surface 33, so that the vacuum in the spinning rotor 30 is maintained while no vacuum is present at the suction opening 52. The fibers 47 thus reach the fiber collecting surface 33 in the spinning rotor 30 due to the negative spin pressure prevailing in the spinning rotor 30.

In order to bring the actuating element 81 into the fiber discharge position, in which the negative pressure at the fiber discharge opening 130 is prevented and instead is effective in the suction opening 52, it is sufficient to shift the actuating element 81 against the action of the spring element 84 by the force acting on the actuating bolt 810. As a result, the control bore 812 is aligned with the vacuum line 51, in which the vacuum is present at the suction opening 52 and the spinning vacuum is switched off in the spinning rotor 30. To reset the control slide 81, the release of the adjusting bolt 810 is sufficient, so that the spring element 84 can move the adjusting element 81 back into the spinning position shown.

The pressure on the adjusting bolt 810 can also be done manually here. When automatic piecing is used, this adjusting bolt 810 is controlled by a movable maintenance carriage 70 via an electromagnet (not shown) or via a drive bolt 71.

So that no fibers 47 and yarn residues can get stuck in the housing 80 and in the control element 81 during suction, provision is made of two control bores 811 and 812 to ensure that the suction air always passes the switching device 8 in a straight line. This is achieved in that each vacuum line 50 and 51 is assigned its own control bore 812 or 811, which can be brought into alignment with the pipe socket 500 and 501 or 510 and 511.

It may happen that at the moment the adjusting element 81 is changed, one or more fibers 47 are in the transition from the pipe socket 510 into the control bore 812 or from the control bore 812 into the pipe socket 511. It can also occur, albeit rarely, that fibers 47 are in the transition area between pipe socket 500 and control bore 811 or between control bore 811 and pipe socket 501 at this time. So that these fibers 47 or yarn ends cannot get jammed between the actuating element 81 and the housing 80 at these stems, the edges 813, 814, 815 and 816 of the control bores 811 and 812 and the edges 800, 801, 802 and 803 of the pipe socket 500 assigned to them , 501, 510 and 511 or the housing 80 are formed with sharp edges so that the stationary and the movable edges 800 and 813, 814 and 801, 802 and 815 as well as 816 and 803 which can be brought into alignment each form cutting devices in pairs. When the control element 81 is switched over, the fibers 47 and yarn remnants located in the area of these cutting devices are severed, so that a part thereof remains in the control bore 811 or 812 and the other part in the vacuum line 50 or 51. A jamming of the actuator 81 is avoided in a safe manner.

In a similar way, the cooperating edges of the switching device 64 (FIG. 1) or 6 (FIG. 2) and the vacuum lines 50 and 51 or associated connecting pieces, not shown, can be designed as cutting devices.

Further modifications are possible by exchanging features with one another or by replacing them with equivalents and combinations thereof and fall within the scope of the present invention. For example, in the embodiments of the piecing device, which were explained with the aid of FIGS. 1 and 2, the two vacuum lines 50 and 51 are connected to a common vacuum source 5 or to a common suction channel 53. If desired, a separate vacuum source can of course also be provided for each vacuum line 50 and 51, it being possible for these vacuum lines 50 and 51 to be connected to these vacuum sources by separate switching devices or by a common switching device 64, 6 or 8. This can be seen particularly clearly when viewing FIG. 3.

Even in the case of a switching device 64 designed as a rotary body valve (FIG. 1), a simple drive from a maintenance vehicle 70 is possible, in that the switching device 64 has a radially outwardly projecting adjusting bolt, which in one direction is driven by the driving bolt 71 (FIG. 2) Maintenance car is acted upon. The resetting can take place with the aid of a spring element designed as a torsion spring.

Fig. 4 shows the example of a friction roller 34 having open-end spinning device, that instead of the opening roller 11, several rollers effecting the fiber transport can also be provided, the first roller 14 serving to dissolve the fiber material to be spun and is therefore designed as an opening roller. The second roller 15, which is rotatably mounted between the opening device 1 and the friction rollers 34, is disk-like formed and has a collection surface 150 on its circumference. The collection surface 150 is connected to the opening device 1 via a feed channel 13 which opens approximately tangentially in the direction of the rotational movement of the collection surface 150 and the width of which is adapted to the collection surface 150.

The roller 15 is mounted on a hollow axis 152 fastened in the machine frame, which extends in a plane perpendicular to the axes 340 of the friction rollers 34, and is driven in the direction of the arrow 460. In the drawing, the roller 15 is for the sake of clarity a relatively large distance from the gusset area of the friction rollers 34. However, the roller 15 should extend as far as possible into the gusset area so that the path of the fibers from the collecting surface 150 into the gusset area is as short as possible.

A controllable suction air nozzle 35 is located on the side of the gusset area of the friction rollers 34 facing away from the take-off rollers 41 and 42.

The fibers are held on the perforated collecting surface 150 by a suction air stream during their transport to the friction rollers 34. For this purpose, the disk-like roller 15 is connected to a suction device (not shown) via the hollow shaft 152. However, the suction air flow acts only in a sector I on the collecting surface 150, which extends in the direction of rotation of the roller 15 from the feeding point of the fibers onto the collecting surface 150 up to its detaching point specified by a transfer sector 11. The transfer sector II is kept separated from the suction air flow by partitions 151 so that the fibers 47 can detach from the collecting surface 150. Opposite the transfer sector II, the housing 10 has an opening 160 of a fiber feed channel 16 leading to the friction rollers 34.

It is advantageous to pneumatically support and accelerate the detachment of the fibers from the collecting surface, so that it is ensured that all fibers get into the spinning gusset. This is done by introducing an air stream into sector II, which flows through the collecting surface in the direction of the friction rollers 34. After at least one of the friction rollers 34 is vacuumed and the housing 10 extends sealingly to over the friction rollers 34, this flow is created by sucking in air from sector II. The air required for this is supplied by a pipe 153 inserted into the hollow shaft 152, which leads to the Sector II connects with the atmosphere, brought up.

If this measure is not sufficient, the pipeline 153 can also be connected to a compressed air device and the collecting surface 150 in sector II can be subjected to a slight overpressure. In addition to the described retention of the fibers on the fiber collection surface during their transport by pneumatic means or independently thereof, the fibers can also be held on the collection surface 150 mechanically, for example by needles (not shown) arranged on the circumference of the collection surface 150.

In order to avoid indifferent air currents in the area of the feeding of the fibers 47 on the collecting surface 150 and to expose the fibers 47 conveyed through the fiber feed channel 13 exclusively to an air stream that stretches them and ensures their oriented placement on the collecting surface 150 in the direction of their movement, a sector II subsequent and up to the mouth of the fiber feed channel 13, sector III is kept free of flow by means of a fixed aperture 154. In addition, in the area of this sector III, a circumferential wall 100 extending up to the collecting surface 150 is provided. The suction opening 52 is arranged in this peripheral wall 100, ie outside the fiber transport path between the fiber discharge opening 160 and the fiber feed channel 13.

For the spinning process, the fiber material is fed via the feed trough 21 as a sliver 40 by means of the delivery roller 20 to the opening roller 14, by means of which the sliver 40 is separated into fibers 47. The negative pressure in sector 1 of the roller 15 creates a transport air flow which transports the individual fibers 47 through the feed channel 13 to the collecting surface 150, on which the fibers 47 are deposited.

The fibers 47, which are fed to the circumferential collecting surface 150 with simultaneous duplication, are transported there via the sector I, on which they are held pneumatically and / or mechanically, to the mouth 160 of the feed channel 16 and, since the collecting surface 150 moves in the gusset area in the thread take-off direction , fed into the gusset area parallel to the thread axis in the transfer sector II. There they are tied to the rotating open thread end and turned into a thread 4.

If a thread break occurs, the supply of fiber material to the opening roller 14 is interrupted by stopping the feed device 2. In addition, the negative pressure in the friction rollers 34 is switched off. In preparation for the piecing process, the thread end is returned to the spinning gusset of the friction rollers 34, which is supported by a suction air flow which is now effective in the suction air nozzle 35. Now the feeding device 2 is switched on. So that no fibers 47 reach the friction rollers 34 in this case, a vacuum is applied to the suction opening 52 on the circumference of the roller 15 via the vacuum line 51. As a result, the air flow flowing through the pipe 153 in the transfer sector II is conducted into the suction opening 52. The fibers 47 supplied by the roller 14 onto the collecting surface 150 follow this air flow and are thus sucked into the vacuum line 51. To a at the time when the thread is returned, the vacuum in the suction air nozzle 35 and in the vacuum line 51 is switched off and instead the vacuum in the friction rollers 34 or one of them is switched on. The thread 4 is withdrawn from the spinning gusset of the friction rollers 34 with the simultaneous incorporation of the fibers 47 now fed back into the spinning gusset.

4, the fiber flow is controlled by the switching of the air flow described. The fibers 47 which are not required when the spinning process is interrupted are removed before they have reached the spinning unit. When piecing, the renewed delivery of the fibers 47 to the spinning unit ensures that only undamaged fibers 47 arrive there. The thread 4 produced thus has a high strength in the area of its piecing.

As shown in FIG. 4 by the broken line, in an alternative embodiment of the device described, the suction opening 52 can also be arranged in the peripheral wall 101 of the opening roller 14 after the mouth 130 of the feed channel 13 provided there instead of in the peripheral wall 100 of the roller 15. In order to prevent that when the suction opening 52 is in the peripheral wall 101 of the opening roller 14 and is under this negative pressure, fibers 47 can still get onto the collecting surface 150 of the roller 15, it is provided that the negative pressure in sector I is the second Roller 15 is controlled synchronously with the negative pressure in the friction rollers 34. Thus, if the fibers 47 are to be sucked off through the suction opening 52 in the peripheral wall of the roller 14, the vacuum in the suction opening 52 is switched on and the vacuum in sector I of the roller 15 and in the friction rollers 34 is switched off.

In order to facilitate the transfer of the fibers 47 from the opening roller 14 or the roller 15 to the subsequent mouth 130 or 160 of the feed channel 13 or 16, it can further be provided that the pipeline 153 alternately to the atmosphere or a compressed air source (not shown) or can be connected to a suction air source (vacuum line 151). For this purpose, if the fibers 47 are to leave the roller 15 through the fiber discharge opening 160 in the direction of the friction rollers 34, the correspondingly configured switching device (compare 64, 6 or 8) connects the pipeline 153 to the atmosphere or the compressed air source, while the suction opening 52 from the vacuum source 5 is separated and a vacuum is applied to the friction rollers 34 via the vacuum line 50.

However, if the fibers 47 are to leave the roller 15 not through the feed channel 16 but through the suction opening 52, the switching rollers separate the friction rollers 34 from the vacuum source 5 and the suction opening 52 following the fiber discharge opening 160 via the vacuum line 51 to the Vacuum source 5 connected. In order to ensure that the fibers 47 are also securely held on the collecting surface 150 in the area of the sector II, the pipeline 153 is simultaneously connected to the vacuum line 51 mentioned. In this way, whenever the suction opening 52 is under vacuum, the sector II of this roller 15 is also under vacuum.

A further modification of the device for performing the described method is shown in FIG. 5.

In this embodiment, the vacuum line 51 ends in a switching device 512 designed as a check valve, with the aid of which the vacuum in the vacuum line 51 can be controlled. The check valve is located in the version shown in a chamber 513, which in turn is arranged at the end of the vacuum line 51, which faces the maintenance carriage 70 which can be moved along the spinning machine 36. An axial guide 514 for the valve cone 515 is located centrally in the chamber 513. The valve cone 515 is acted upon by a spring element 516 which is supported at its other end on spokes 517, with the aid of which the guide 514 is rigid with the peripheral wall of the chamber 513 connected is. On its side facing the maintenance carriage 70, the chamber 513 has an opening 519 which is surrounded by a valve seat 518 and which can be closed or opened by the valve cone 515.

In addition to the vacuum source 5 provided in the spinning machine 36, there is a second vacuum source 73 in the maintenance carriage 70.

From the vacuum source 73, a telescopic suction air line 74 extends in the direction of the spinning machine 36. The suction air line 74 is assigned a drive device 75, through which the mouth 740 of the suction air line 74 is brought into a sealing arrangement against the wall of the chamber 513 facing the maintenance car 70 or from this can be withdrawn. In the mouth 740 of the suction air line 74, a pin 742 is held with the aid of spokes 741, which axially projects beyond the mouth 740 in the direction of the spinning machine 36 and, when the mouth 740 abuts the chamber 513, holds the valve cone 515 at a distance from its valve seat 518 and thus the valve opens.

During normal spinning, the fiber feed into the feed channel 13 is released, while the switching device 512 designed as a check valve assumes its closed position. The fibers 47 thus pass through the mouth 130 of the feed channel 13 onto the fiber collecting surface 33 of the spinning rotor 30 or of the friction rollers 34, where they are bound into the end of the thread 4.

If the thread 4 breaks, the spinning rotor 30 is stopped via a thread monitor (not shown) and the fiber feed to the opening roller 11 is prevented, the spinning vacuum in the spinning rotor 30 being maintained further.

After reaching the spinning position concerned, the spinning rotor 30 is cleaned in a known manner by control from the maintenance carriage 70, and the thread end is prepared so that it has a favorable piecing shape. The spinning rotor 30 is then released again. This runs up. While the rotor is ramping up or after the rotor operating speed has been reached, the thread end is returned in a customary manner, forming a thread reserve, to a standby position in the thread take-off tube 32 (FIG. 1), where the negative pressure applied to the housing 31 is still effective.

Then the fibers 47, which were previously damaged by the running opening roller 11 when the feed device 2 is shut off, are removed so that they do not get into the spinning rotor. In this case, the connecting movement of the suction air line 74 emanating from the vacuum source 73 to the switching device 512 switches it over, so that the vacuum generated in the vacuum source 73 is now present at the suction opening 52. The fibers 47 fed to the opening roller 11 after switching on the feed device 2 are thus conveyed over the mouth 130 to the suction opening 52 and from there via the vacuum line 51, the chamber 513 and the suction air line 74 to the vacuum source 73 of the service vehicle 70.

In accordance with the timing of the return of the thread, the fiber feed into the spinning rotor 30 is released again, where the fibers connect to the end of the thread that has now reached the spinning rotor 30 by releasing the thread reserve. The thread 4 is then drawn off again from the spinning rotor 30 in a known manner with the aid of the take-off rollers 41, 42 and the bobbin 44 (FIG. 1), the fibers 47 newly arriving on the fiber collecting surface 33 being integrated.

If the fiber stream reaches the spinning unit (spinning rotor 30 or friction rollers 34), the suction air stream acting in the suction opening 52 is meaningless. It no longer has any influence on fiber transport. In order to save energy costs for the generation of negative pressure, after the piecing process has ended, the negative pressure behind the mouth 130, ie. H. in the vacuum line 51, turned off. In the embodiment shown in FIG. 5, this takes place in that the maintenance device 70 withdraws the suction air line 74 at least to the extent that the pin 742 releases the valve cone 515. This is thus brought into contact with its valve seat 518 by the spring element 516. The opening 519 is closed, so that air cannot flow through the opening 519 in either direction. Thus, no air that could otherwise interfere with the fiber transport and the spinning process gets into the opening roller housing 10.

The switching device can also be designed differently than shown. For example, it is designed as a slide valve, which is acted upon by a spring element in the closed position and can be brought into the release position by the connecting movement of the suction air nozzle 74 (FIG. 5) arranged on the maintenance car 70 to the vacuum line 51.

Another embodiment of a switching device 86 is shown in FIG. 6. Here, a flap 860 is provided, which is articulated above the mouth 861 of the vacuum line 51 facing the maintenance car 70. The mouth 861 forms a valve seat, which is inclined obliquely in such a way that the flap 860 seals against the valve seat due to its own weight. The flap 860 is located together with its mouth 861 of the vacuum line 51 in a chamber 862, which is open on its side facing the maintenance car 70. From the maintenance carriage 70, the mouth 740 of the suction air line 74 can be sealingly brought into contact with the open side of the chamber 862, as is indicated by dashed lines in FIG. 6.

As long as the suction air line 74 is not in contact with the chamber 862 or as long as there is no negative pressure on the suction air line 74 in contact with the open side of the chamber 862, the flap 860 assumes the position shown in full lines, the sealing abutment of the flap 860 on the Mouth 861 is supported by the negative pressure prevailing in the opening roller housing 10. If, after the mouth 740 of the suction air line 74 is applied to the chamber 862, negative pressure is applied to the suction air line 74, the flap 860 lifts off from the mouth 861 (dashed position 860 '), and the fiber stream can get into the suction air line 74.

Although the devices according to FIGS. 5 and 6 have only been described using the example of opening rollers 11, it goes without saying that they can also be used in conjunction with an additional roller 15 according to FIG.

A switching device 512 or 86 designed as a check valve for controlling the negative pressure in the negative pressure line 51 has been described above. However, it is also conceivable to provide a shut-off valve on the spinning machine 36 which is actuated from the maintenance carriage 70 and the vacuum line 51 with a vacuum source provided on the spinning machine 36 itself connects or not, which is independent of the vacuum source 5. It is also conceivable to actuate a switch from the maintenance carriage 70, via which a fan is switched on or off. Likewise, the suction air line 74 (FIG. 5) can also be connected via the maintenance carriage 70 to a vacuum source provided on the spinning machine 36.

Claims (16)

1. Process for thread joining in an open end spinning apparatus having a sliver feeding apparatus and an opening cylinder which is arranged in a housing and from which the fibres are supplied in an air stream generated by the spinning underpressure through a feed channel to a fibre collecting surface rotating in a housing, in which process, during the thread joining operation, a thread end is returned to the fibre collecting surface from which the previously returned thread is then removed again while fibres are continuously bound in, where, to eliminate fibres undesired for thread joining, the feeding apparatus is switched on and the fibre stream is supplied across the feed channel mouth to a suction removal means arranged downstream of the feed channel mouth in the opening cylinder housing so that the fibres do not reach the feed channel and the fibre stream is only deflected into the feed channel when the actual joining procedure starts, characterised in that, for introduction of the thread end into the spinning apparatus, the spinning underpressure is active, in that the thread end is only returned into the spinning apparatus to such an extent that it does not touch the fibre collecting surface, in that the spinning underpressure is then switched off while the suction removal means arranged in the opening cylinder housing is effective so that on switching on of the feeding apparatus the fibre stream is guided across the feed channel mouth and removed by suction until, on starting of the actual thread joining procedure, the thread end is returned to the fibre collecting surface, said suction removal means is switched off again and the spinning underpressure is switched on again so that the fibre stream is supplied to the fibre collecting surface.
2. Process according to claim 1, characterised in that the switching off and switching on again of the spinning underpressure takes place between a suction air source and the fibre collecting surface.
3. Process according to claim 1 or 2, characterised in that, to eliminate fibres undesired for thread joining, the fibre stream is first guided across the mouth of the feed channel, in that the fibre stream is then briefly supplied to the fibre collecting surface and is then guided again across the mouth of the feed channel and the fibre stream is only supplied to the fibre collecting surface again after the thread end has reached the fibre collecting surface and removal of the thread has begun.
4. Process according to one or more of claims 1 to 3, characterised in that, to eliminate fibres undesired for thread joining, an underpressure is brought into effect outside the fibre transport path opposite the periphery of a fibre transport cylinder downstream of the opening cylinder, instead of at the periphery of the opening cylinder.
5. Apparatus for thread joining in an open end spinning apparatus, having a sliver feeding apparatus, an opening cylinder housing with an opening cylinder, a fibre collecting surface rotating in a housing, a feed channel leading from the opening cylinder housing to the fibre collecting surface, an underpressure source for generating the spinning underpressure and a suction opening in the peripheral wall of the opening cylinder housing, for carrying out the process according to one or more of claims 1 to 4, characterised by a switching apparatus between the underpressure source (5) and the fibre collecting surface (33, 150) for switching the spinning underpressure on and off and a switching apparatus for switching the underpressure on and off at the suction opening (52).
6. Apparatus according to claim 5, characterised by a thread return apparatus for returning the thread end to a ready position within the thread removal tube, a discard apparatus for releasing the thread end for its return to the fibre collecting surface and a control apparatus for controlling the thread joining procedure and the switching apparatuses.
7. Apparatus according to claim 6, characterised in that the switching apparatuses (6, 8) are part of a switch-over apparatus by means of which the underpressure source (5) is connectable alternately to the fibre collecting surface (33, 150) as a spinning underpressure or to the suction opening (52) for removal of the fibres by suction.
8. Apparatus according to one or more of claims 5 to 7, characterised in that the switching apparatus (8) has two control bores (811, 812) whereof the one may be brought flush with a first underpressure line (50) to the fibre collecting surface (33) and the other may be brought flush with the second underpressure line (51) to the suction opening (52).
9. Apparatus according to one or more of claims 5 to 8, characterised in that the stationary edges (800, 801, 802, 803) and the edges (813, 814, 815, 816), movable to be brought flush therewith, of the switching apparatus (6, 64, 8) are constructed as cutting apparatuses.
10. Apparatus according to one of claims 5 to 9, characterised in that the switching apparatus (6, 8, 85, 512, 9) is actuated in one direction of movement by a control drive (92), whereas a spring element (612, 622; 84; 850; 516; 93) is provided for the return.
11. Apparatus for carrying out the process according to one or more of claims 1 to 4, having an underpressure source for generating the spinning underpressure and a controllable suction opening in the peripheral wall of the opening cylinder housing, characterised by a second underpressure source (73) arranged on a maintenance carriage (70) which is displaceable along a plurality of spinning apparatuses and by a switching apparatus (6; 512, 9) for the alternate switching on of the underpressure source (5) for generating the spinning underpressure and the underpressure source (73) for eliminating fibres undesired for thread joining.
12. Apparatus according to one or more of claims 5 to 11, characterised in that the switching apparatus (6, 64, 8, 85, 86, 512, 9) is controllable from a maintenance carriage (70) which is displaceable along a plurality of spinning apparatuses.
13. Apparatus according to claims 11 and 12, characterised in that the switching apparatus (512) is controllable by the connecting movement of a suction air line (74) emanating from the maintenance carriage (70) to the switch-over apparatus (512).
14. Apparatus according to claims 11 and 12, characterised in that the switching apparatus (86) is controllable by the underpressure in a suction air line (74) emanating from the maintenance carriage (70).
15. Apparatus according to claim 14, characterised in that the switching apparatus (512, 86) contains a non-return valve.
16. Apparatus according to one or more of claims 5 to 15, characterised in that a fibre transport cylinder (15) is downstream of the opening cylinder (14) and the suction opening (52) is arranged in a peripheral wall (100) surrounding the transport cylinder (15) instead of in the peripheral wall (101) surrounding the opening cylinder (14).

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