EP0346376B1 - Process and device for joining a thread to a spinning device with pneumatic twister - Google Patents

Abstract

In order to join a thread to a spinning device with pneumatic twister (3), one end of the thread (12) is returned through the pneumatic twister (3) to a drawing system (2) and then introduced laterally between the two delivery rollers (23, 230) of the drawing system (2). It is then tied to a roving (1) and drawn through the twister (2) as a continuous thread. When the end of the thread (12) is returned through the twister (3) located in front of the two delivery rollers (23, 230) of the drawing system (2) as far as the entry (308) of the twister (3), the end of the thread (12) is grasped and conveyed to a gripper (7) adjacent to the drawing system (2). The gripper (7) pulls the end of the thread along the drawing system (2) past the delivery rollers (23, 230), so that it can then be introduced between the said rollers. A thread feeder (6) introduces the end of the thread leaving the twister (3) through its entry. The thread feeder (6) has the form of a compressed air nozzle (60) essentially parallel to the nip of the pair of delivery rollers (23, 230). The orifice (600) of the thread feeder (6) is arranged on the side of the twister (3) opposite the gripper (7) and faces the gripper (7).

Description

The present invention relates to a method for piecing a spinning device working with a pneumatic twist element, in which a thread end is returned from the exit side through the twist element to a drafting system and then inserted laterally into the pair of exit rollers of the drafting system, from where it is integrated with a fuse is drawn off as a continuous thread through the swirl element, and a device for carrying out this method.

In a known method of this type, the swirl element is laterally displaced for re-spinning so that its entry side is accessible (DE-OSes 3.411.577 and 3.413.894). Then a thread end is drawn off from the bobbin and inserted into the swirl element from the exit side. A suction pipe is fed to the inlet side of the swirl member, which pulls the thread end through the swirl member. The swirl member is then returned to its spinning position and the thread section extending from the swirl member to the suction tube is inserted into the pair of outlet rollers of the drafting system. Then the spinning process to be resumed. In this known piecing, it is disadvantageous that the swirl member for the return of the thread end to the drafting device has to be displaced laterally. On the one hand, additional space is required for this lateral displacement of the swirl element in addition to the swirl element, which prevents a compact design. On the other hand, when the swirl member is returned to its spinning position, there is a risk that it will not return exactly to its starting position, as a result of which the spinning process and the yarn failure are impaired.

Since in a spinning device the undisturbed spinning process is to be regarded as the normal case and the piecing process as an exceptional situation, the terms used in connection with the present invention, such as “inlet side” or “inlet mouth” or “outlet side” or “outlet mouth” of the swirl member always on this normal case. The "entry side" or "entry mouth" of the swirl element is thus the side facing the drafting system or mouth of the swirl element, since the thread in the draw-off reaches the swirl element on this side during the normal spinning process and the swirl element on the side facing away from the drafting system leaves again.

In the sense of the present invention, a "fuse" is to be understood as any band-like fiber material which can be warped by means of a drafting device and fed to the swirl element, regardless of whether it has a slight twist or not. This term does not only include flyers, but also card tapes etc.

The object of the present invention is to provide a method and a device for spinning on a spinning device working with a pneumatic twisting device, by means of which an offset of the twisting device for returning the thread can be dispensed with, so that a space-saving construction of the spinning device is achieved and an optimal setting of the swirl organ is always guaranteed for spinning.

This object is achieved according to the invention in a generic method in that the thread end is conveyed through the swirl member located after the pair of exit rollers of the drafting system to its entry side, is grasped there and is fed to a gripper located next to the drafting system, which then feeds the thread end for later insertion pulls into the pair of exit rollers past this next to the drafting system. Because the thread emerging from the swirl member on the inlet side is detected between the drafting device and the swirling device and fed to a gripper located next to the drafting device, it is not necessary to displace the swirling device laterally, so that it assumes its spinning position unchanged. In addition to the drafting system, there is only sufficient space for a gripper which can be moved essentially parallel to the direction of movement of the fiber material and thus does not require much space. Because the twist element does not change its position in relation to the drafting system even for spinning, it is ensured that the twist element assumes an optimal position with respect to the drafting system before and after the piecing process, which increases the spinning safety.

Preferably, the thread end returned through the swirl member is exposed to a compressed air stream oriented essentially parallel to the clamping line of the pair of outlet rollers for the feed to the hook. In this way, a secure feeding of the thread end to the hook is achieved in a simple manner, without the need for exact control over time.

If the compressed air flow, which feeds the thread end to the hook, is turbulent, there is a risk that the thread end will be guided past the hook by the air turbulence and therefore cannot be grasped by it. To avoid such malfunctions, it is therefore provided in an advantageous embodiment of the method according to the invention that the thread end returned through the swirl member is fed to the gripper with the aid of a laminar compressed air stream.

In order to increase the security for feeding the thread end to the gripper, it can alternatively or additionally be provided that a thread reserve is built up before the return of the thread end through the swirl member, which then during the return delivery of the thread end through the swirl member into the transverse to Thread flow acting compressed air flow is dissolved so slowly that the thread end is kept stretched by the compressed air flow while it is being fed to the hook. Due to the slow dissolution of the thread reserve, the end of the thread emerging from the entry opening of the swirl element is successively grasped by the compressed air flow, thereby ensuring this stretched thread supply to the hook.

The air flow to which the thread end is exposed during its return delivery should be as weak as possible, so that on the one hand it ensures the return delivery but on the other hand does not dissolve the end of the thread. Air turbulence should also be avoided. For this reason, according to an advantageous feature of the method according to the invention, it is provided that the compressed air flow is switched off and the thread end has been gripped by the gripper.

At the start of thread withdrawal, individual fibers that detach from the fuse have a tendency to attach themselves to the thread. However, these individual fibers cannot be properly integrated and form unsightly knobs and sliders in the finished thread. If the beginning of the match is delivered to a suction device after it emerges from the drafting system, this match is subject to the suction effect of both the match suction and the swirl device after the spinning overpressure in the swirl element has been switched on. This creates undefined vacuum conditions in the area between the drafting system and the swirl element, which leads to malfunctions in the piecing process. In order to avoid these disadvantages, it is advantageous if, after resuming the thread take-off, the thread end and the fuse between the exit roller pair of the drafting device and the swirl element are exposed to a compressed air stream oriented essentially parallel to the clamping line of the exit roller pair.

If the compressed air flow oriented transversely to the thread take-off device remains switched on for too long, there is a risk of a thin spot in the newly spun thread following the piecing device. To avoid this, according to a further advantageous embodiment of the method according to the invention, it is provided that the compressed air flow which is switched on after the thread take-off is switched off before the end of the thread leaves the pair of exit rollers of the drafting system.

It has been shown that individual fibers which are attached to the thread in the take-off can be blown off the thread particularly safely if the compressed air flow is tangentially removed from the core rotation of the thread extending from the drafting device to the swirl element.

In order to avoid that the returned thread end, while it is exposed to the compressed air flow directed against the hook, can turn up in the air flow, it is expediently provided that during the return of the thread, a significantly weaker compressed air flow is brought to bear on the thread end than after resumption of the thread take-off . The strength of the compressed air flow is such that the thread end is still safely fed to the hook, but without the risk that the thread end will unwind.

During the spinning process, larger and larger deposits form in the swirl organ, which then detach from time to time and can be carried away by the thread in the take-off. For this reason, the swirl member is preferably cleaned in connection with the piecing process before or during the return of the thread end. This cleaning can in principle be carried out by compressed air, which is effective in the swirl element, even before the thread end is inserted into the swirl element for return to the drafting unit. Such cleaning can also be combined with the return delivery process, for example by using a brush for returning the thread end.

However, a return delivery of the thread end can be accomplished in a particularly simple manner according to the invention in that it is brought by a compressed air flow from the exit side of the swirl element through the swirl element into the region of the compressed air flow acting transversely to the thread path.

A simple control of the compressed air stream acting transversely to the yarn path can be achieved according to the invention in that it only acts during the pneumatic return delivery of the yarn end through the swirl member as long as the compressed air stream causing the yarn return is effective in the swirl member.

The gripper expediently works pneumatically, a negative pressure being generated in it at least for the duration until the thread end is inserted into the drafting system. Such a pneumatic gripper has the advantage that it can safely remove a thread end resulting from a thread break and that on the other hand it can also serve to remove fibers which are blown off the thread end after the thread take-off has been reinstated.

In principle, the thread end can be inserted into the drafting system in different ways. For example, the inclined position of the gripper, which is withdrawn parallel or obliquely to the run of the fiber material, can suffice for this. In order to achieve a time-defined insertion of the thread end into the exit roller pair of the drafting system, in an advantageous embodiment of the method according to the invention it is provided that the thread end, after it has been pulled next to the drafting system, is in the form of a loop in the area between the last two pairs of rollers of the drafting system is pulled. It is advantageous if the thread end is simultaneously brought into the effective range of a thread brake during this loop-shaped pulling into the area between the last two roller pairs of the drafting system. In this way it is ensured that the thread end cannot suddenly jump together after being released by the gripper and thus can assume a non-parallel position with respect to the fuse, which would lead to an error in the piecing.

In order to achieve a safe and defined insertion of the thread end into the exit roller pair of the drafting device, it can be expediently provided that the thread end is brought into the region of the clamping line of the exit roller pair during insertion into the drafting device.

According to a preferred embodiment of the method according to the invention, the swirl element is cleaned by a first compressed air stream oriented in the direction from the exit edge of the swirl element to its inlet side. The thread end is then exposed to this first compressed air flow for return delivery to the entry side of the swirl member, in order to be exposed there to a second compressed air flow acting transversely to the transport direction, which feeds the thread end to a gripper, which then pulls the thread end past the pair of outlet rollers to the side of the drafting system. Then the previously stopped fuse is released and suctioned off between the drafting system and the swirl element. Thereupon, the thread end extending to the hook is fed in loop form to a thread brake in the area between the last two roller pairs of the drafting system and is thereby inserted into the pair of exit rollers of the drafting system. The thread end is now subjected to a deduction again. At the same time, the fuse and loose fibers are sucked into the swirl organ by switching on again of the second compressed air flow is prevented. Then, even before the thread end has reached the pair of exit rollers of the drafting system, the suction of the sliver and the second compressed air stream are switched off. Finally, the spinning overpressure acting in the take-off direction is brought into effect again in the swirl organ.

According to a further, likewise very advantageous method, the swirl member is cleaned by a first compressed air flow acting counter to the withdrawal direction and the thread end is then exposed to this first compressed air flow and brought by it from the exit side of the swirl member to its entry side. There, the thread end is exposed to a second stream of compressed air acting transversely to the transport direction and fed through it to a gripper, which then pulls the thread end past the pair of outlet rollers to the side of the drafting system. Subsequently, the thread end extending to the hook is loop-fed to a thread brake in the area between the last two pairs of rollers of the drafting system, thereby being inserted into the pair of exit rollers of the drafting system and subjected to a take-off again. Then the previously stopped fuse is released, while sucking the fuse and loose fibers into the swirl element is prevented by switching on the second compressed air stream again. When the thread end has been pulled out of the drafting device to a predetermined length, the suction of the sliver and the second compressed air flow are switched off again. Finally, the spinning overpressure acting in the take-off direction is brought into effect again in the swirl organ.

To carry out the method is in a device with a pneumatic swirl member, a return delivery element for returning the thread end from the exit side of the swirl member to its entry side and with a gripper for retracting the thread end from the entry side of the swirl member past the pair of outlet rollers until, in addition to the drafting device, a thread feeder is provided according to the invention for detecting the thread end emerging from the entry end of the swirl member upon return and for feeding it to the hook. This thread feeder makes it unnecessary for the twisting element to be moved laterally for piecing.

The thread feeder is preferably designed as a compressed air nozzle oriented essentially parallel to the clamping line of the pair of outlet rollers, the mouth of which is arranged on the side of the swirl member opposite the gripper and faces the gripper.

It has proven to be advantageous if the swirl element has an axial projection on its inlet side and the compressed air nozzle is arranged opposite the swirl element in such a way that the compressed air flow leaving the compressed air nozzle affects the end face of the projection. In this way, the air flow is deflected in the direction of the swirl element due to the formation of eddies in the area after the projection. As a result, the thread end moves somewhat away from the outlet roller part of the drafting device, which increases the safety when feeding the thread end to the hook.

So that the swirl element can be arranged as close as possible to the rollers of the pair of outlet rollers, which has proven to be advantageous for the spinning process, it is provided in a further embodiment of the device according to the invention that the compressed air nozzle is at least partially arranged in the gusset of the pair of outlet rollers of the drafting system facing the swirl element . In order to avoid lint deposits on the top roller of the pair of outlet rollers of the drafting system, it is expediently provided that the compressed air nozzle is at a distance of at least 1 mm from this top roller.

A laminar flow of compressed air increases the safety when feeding the thread from the twist element to the hook. Therefore, it is provided according to a further dual feature of the invention that the mouth of the compressed air nozzle has an inner diameter with a constant cross section.

It has proven to be particularly expedient to arrange the compressed air nozzle tangentially to the thread end extending from the drafting device to the swirl element in such a way that the compressed air nozzle is directed against the direction of flow of the compressed air flow causing the core rotation of the chamfer end, which is generated by the compressed air holes in the swirl element. This ensures that after the thread take-off is resumed, but before the thread end has left the drafting device, the fuse or individual fibers are prevented by the compressed air flow from being drawn into the swirl element from the thread end.

If a swirl element is used which has only a single row of compressed air holes tangentially opening into the axial bore of the swirl element, then the compressed air nozzle is oriented tangentially to the elongated axial hole of the swirl element in the opposite direction to the flow direction of the compressed air flow leaving the compressed air holes. If, on the other hand, a swirl member is used which has two rows of compressed air bores in succession in the thread take-off direction, one row of which opens in one circumferential direction and the other row in the opposite circumferential direction into the axial bore of the swirl member, the invention provides that the compressed air nozzle is tangential to the elongated one Axial bore of the swirl member is oriented in the opposite direction to the circumferential direction in which the compressed air holes of the second row in the thread take-off direction open into the axial bore of the swirl member.

Since it has been shown that it is advantageous to use the weakest possible air flow for the feeding of the thread end to the hook so that the thread end does not unwind, while for the blowing off of individual fibers or the beginning of the sliver from the thread end in the take-off a stronger one Overpressure is advantageous, it is provided according to a further embodiment of the device according to the invention that the compressed air nozzle is assigned a device for optionally applying a higher or a lower overpressure.

It is advantageous if the compressed air nozzle is controlled as a function of the thread length still in the drafting device. For this reason, a control device is expediently assigned to the compressed air nozzle, and a thread monitoring device connected to this control device is assigned to the gripper.

According to a preferred embodiment of the subject matter of the invention, in addition to compressed air bores in which there is overpressure during the spinning process and which have a component in the take-off direction, the swirl member has further compressed air bores in which overpressure is present during the yarn return and which have a component in the return delivery direction. These compressed air holes, which are oriented in the return direction, can be pressurized with excess pressure both for returning the thread end and for cleaning the swirl element.

If a twist organ is used for the pneumatic return of the thread end through the twist organ into the area of the thread feeder, which has an injector nozzle in a row in the thread take-off device and a twist brake separated from it by a gap, there is a risk that the thread end will be returned when it is returned stuck in the area between the two nozzles of the swirl element. To prevent this, it can be provided in a further expedient embodiment of the device according to the invention that both the injector nozzle and the swirl nozzle each have at least one compressed air bore oriented in the return direction, wherein a stronger air flow can be generated in the injector nozzle than in the swirl nozzle. This can be achieved in different ways, for example by different inclinations of the compressed air bores in the swirl nozzle and in the injector nozzle. It is preferably provided for this purpose that the compressed air bore in the injector nozzle has a larger diameter than the compressed air bore in the swirl nozzle.

Since the compressed air nozzle in the pneumatic return delivery of the thread end should only be effective for the duration of this return delivery in order to prevent the thread end from being unscrewed, it is provided according to a simple and expedient embodiment of the subject-matter of the invention that the return delivery of the fader end causes compressed air bores of the swirl element and the Compressed air nozzle are assigned a common supply line and a common control valve.

It is not absolutely necessary for the thread to be pneumatically returned to the area of the thread feeder by the swirl element. In an alternative embodiment of the device according to the invention, a mechanical threading element can also be provided for returning the thread end through the swirl element into the stroke area of the thread feeder. This threading element is expediently designed as a clamp. However, in an alternative advantageous embodiment of the mechanical threading element, it is also possible to use this as Train brush, which brush can be assigned a scraper. Compared to a threading element designed as a clamp, a brush has the additional advantage that, during its axial relative movement in the swirl element, it wipes off deposits that could have settled in the axial bore of the swirl element, thus cleaning the swirl element.

For an elongated feed of the thread end to the hook, which also ensures a secure pick-up of the thread end by the hook, it is advantageous if the thread end is slowly returned through the twist element. In addition, it is expedient that the return delivery length is defined, so that the length of the piecing can also be easily predetermined. In order to achieve this goal, a thread reserve device with a drive is advantageously provided on the outlet side of the swirl element, which drives the thread reserve device so slowly that the thread end leaving the mouth of the swirl element is stretched by the thread feeder during the feed to the gripper.

In principle, the gripper can be designed differently, for example as a pair of rollers, which grips the thread in a clamp-like manner and pulls it out of the swirl element due to its rotation and, after the gripper has been axially displaced for holding, also brings it into the region of a stationary suction air opening after release by the pair of rollers. However, the gripper is expediently designed as a suction air nozzle, which advantageously has a suction opening facing the thread feeder.

The gripper not only has the task of grasping the thread end fed to it by the thread feeder, but is also intended to insert this thread end into the pair of outlet rollers of the drafting system. In principle, this can also be done Different ways happen, for example, that in a gripper designed as a suction air nozzle, the thread end exits through an initially covered and later released slot and thus reaches the area of a thread insert, which then inserts the thread end into the drafting system. Expediently, however, the gripper can be moved from a receiving position, in which it cooperates with the thread feeder, into an insertion position next to the drafting system.

In principle, the thread end can be inserted into the drafting device by a corresponding movement of the gripper, but a thread insert is preferably provided for this purpose, which can be moved from a standby position next to the drafting device into an insertion position such that it extends the course of the twisting element to the gripper Crosses the thread end and introduces it into the drafting system as it moves further. In this area of the drafting device, a thread brake is expediently provided, to which the thread end can be fed during its insertion movement. With this thread brake, the thread end can be retained even after release by the gripper, so that a parallel position of the thread end to the fuse is ensured during the entire thread take-off movement.

In principle, the thread brake can be located at any point on the thread path between the gripper and the pair of outlet rollers of the drafting system; however, the aim is to arrange this thread brake as close as possible to the pair of exit rollers of the drafting system so that the end of the thread is controlled practically over the entire distance between the hook and the pair of exit rollers. For this reason, it is advantageously provided that this brake is located between the last two pairs of rollers of the drafting system. It is particularly advantageous if the thread insert is in its insert position forms an elastic thread clamp together with the thread brake. The thread brake, against which the thread insert presses the thread end, preferably has a clamping surface made of soft rubber or felt.

In order to ensure a safe and rapid insertion of the thread end into the exit roller pair of the drafting device, in a further embodiment of the device according to the invention it is provided that a thread guide is assigned to the top roller of the exit roller pair of the drafting device, which the thread end during the retraction next to the drafting device until it is inserted into holds the drafting system in the half of the front side of the top roller facing the clamping line of the pair of outlet rollers. In a simple embodiment, this can be done in that the thread guide is formed by an axial, essentially cylindrical projection of the top roller on its side facing the hook, the diameter of the projection being smaller than the diameter of the top roller. A rapid insertion of the thread end into the pair of outlet rollers of the drafting unit can additionally be supported in that the top roller of the pair of outlet rollers has one or more notches in its edge facing the hook between the lateral surface and the end face.

Nowadays, it is customary to carry out the spinning on spinning machines with the aid of a piecing carriage which runs along a machine with a large number of similar spinning positions. If the device according to the invention is used in connection with a machine with a large number of such spinning positions, it is also particularly advantageous here if one or more of the elements required solely for the piecing process are arranged on such a piecing carriage.

The present invention makes it possible to carry out piecing in a safe manner without changing the arrangement and storage of the elements required for the normal spinning process, the invention permitting a space-saving design. The invention also enables precise control of the piecing process in such a way that the length of the attachment point in the thread can be kept very short and exactly predetermined. In this way, inconspicuous and secure piecing in the thread is achieved.

The device according to the invention is simple in construction and enables the use of a piecing carriage in a particularly simple manner, since it is not necessary to adjust elements on the swirl element or drafting system on the machine side in order to carry out the piecing process. All that is required is an electrical control of air pressures or a sliver stop device, which are already controlled from the spinning station even if the thread breaks. All other elements that are only required for piecing can thus be arranged on the piecing carriage.

• Fig. 1 in schematischer Draufsicht eine erfindungsgemäß ausgebildete Spinnvorrichtung;
• Fig. 2 die in Fig. 1 gezeigte Spinnvorrichtung in schematischer Seitenansicht;
• Fig. 3 in schematischer Darstellung einen Ansetzer, von welchem während des Anspinnvorganges die losen Fasern nicht abgeblasen wurden;
• Fig. 4 in schematischer Darstellung einen anderen Ansetzer, bei welchem während des Anspinnvorganges lose Fasern abgeblasen wurden;
• Fig. 5 ein Funktionszeitdiagramm mit Angabe der Arbeitsgänge, die nach dem Verlegen des Fadenendes neben das Streckwerk für das Ansetzen erforderlich sind;
• Fig. 6 in der Draufsicht das Austrittswalzenpaar des Streckwerkes, das Drallorgan sowie eine Druckluftdüse, die auf das im Drallorgan geführte Fadenende gerichtet ist;
• Fig. 7a und 7b im Querschnitt die Dralldüse bzw. die Injektordüse des Drallorgans sowie die Mündung der Druckluftdüse;
• Fig. 8 im Querschnitt die Anordnung der Druckluftdüse zu einem Drallorgan mit nur einem einzigen Satz von Druckluftbohrungen;
• Fig. 9 in der Draufsicht die Anordnung der Druckluftdüse gegenüber dem Austrittswalzenpaar des Streckwerkes und dem Drallorgan;
• Fig. 10 das in Fig. 9 gezeigte Detail in der Seitenansicht;
• Fig. 11 ein Drallorgan mit einem als Klemme ausgebildeten Einfädelelement;
• Fig. 12 eine Draufsicht auf eine abgewandelte erfindungsgemäße Vorrichtung;
• Fig. 13 ein Detail einer abgewandelten Ausführung des Erfindungsgegenstandes mit einem als Bürste ausgebildeten Reinigungs- und Einfädelelement in schematischer Seitenansicht; und
• Fig. 14 im Querschnitt das in Fig. 1 gezeigte Drallorgan.

The invention is explained in more detail below with reference to exemplary embodiments shown in the drawings. Show it:

• Figure 1 is a schematic plan view of a spinning device designed according to the invention.
• FIG. 2 shows the spinning device shown in FIG. 1 in a schematic side view;
• 3 shows a schematic illustration of a piecing device from which the loose fibers were not blown off during the piecing process;
• Fig. 4 in a schematic representation another piecer, in which loose fibers were blown off during the piecing process;
• Fig. 5 is a functional timing diagram indicating the operations that are required after the laying of the thread end next to the drafting system for the attachment;
• 6 is a top view of the pair of outlet rollers of the drafting unit, the swirl element and a compressed air nozzle which is directed towards the thread end guided in the swirl element;
• 7a and 7b in cross section the swirl nozzle or the injector nozzle of the swirl element and the mouth of the compressed air nozzle;
• 8 shows in cross section the arrangement of the compressed air nozzle to form a swirl element with only a single set of compressed air bores;
• 9 is a top view of the arrangement of the compressed air nozzle with respect to the pair of outlet rollers of the drafting system and the swirl element;
• FIG. 10 shows the detail shown in FIG. 9 in a side view;
• 11 shows a swirl element with a threading element designed as a clamp;
• 12 shows a plan view of a modified device according to the invention;
• 13 shows a detail of a modified embodiment of the subject of the invention with a cleaning and threading element designed as a brush in a schematic side view; and
• Fig. 14 in cross section the swirl member shown in Fig. 1.

First, the structure of the spinning device is explained with the aid of FIGS. 1 and 2.

In the spinning device shown, a sliver 1 or a fiber sliver is drawn to the desired strength by means of a drafting device 2 and then fed to a pneumatic twisting device 3, where the sliver 1 or the fiber sliver is spun into a thread 10. The thread 10 is drawn off from the swirl member 3 with the aid of a take-off device 4 and is fed via a thread tension compensation bracket 40 to a winding device 41, where the thread is wound up into a bobbin 42. The drafting unit 2 shown has 4 pairs of rollers with the rollers 20 and 200, 21 and 210, 22 and 220 as well as 23 and 230. In front of the rollers 21, 210 of the third to last pair of rollers and before the rollers 20, 200 of the pair of rollers connected upstream of this one is in each case Matching device 241 and 240 are arranged, to which a common drive device 24 is assigned (see operative connections 243 and 244).

The two rollers 22, 220 are each wrapped by a strap 221 and 222, respectively (see also FIG. 10).

A suction nozzle 25 is assigned to the lower roller 23 of the pair of outlet rollers 23, 230 in the area between the drafting unit 2 and the swirl body 3.

Due to the compressed air supplied to the pneumatic swirl element 3 via a controllable compressed air line 32, the thread 10 receives an incorrect rotation, which is then largely canceled again. For this purpose, the swirl member 3 shown has one injector nozzle 30 and one swirl nozzle 31, viewed in the thread take-off direction, which are carried by a common holder, not shown. 7b and 14 show, the injector nozzle 30 has two compressed air bores 300 and 301 which are tangential in open the axial bore 302 of the injector nozzle 30. 7a and 14 show that the swirl nozzle 31 has three compressed air bores 310, 311 and 312 which open tangentially into the axial bore 313 of the swirl nozzle 31. A comparison of FIGS. 7a and 7b shows that the compressed air bores 300 and 301 open into the axial bore 302 assigned to them in the opposite direction to the compressed air bores 310, 311 and 312. This is illustrated by arrows 303 in Fig. 7b and 314 in Fig. 7a.

The compressed air bores 300 and 301 as well as 310, 311 and 312 are inclined in the draw-off direction (see arrow 44 in FIGS. 1 and 14), so that the thread 10, when there is overpressure during the spinning process on the swirl element 3, a movement component in the direction thereof Arrow 44 is issued.

The compressed air bores 300, 301 or 310, 311 and 312, although they are arranged tangentially to the axial bore 302 or 313, are drawn in the sectional plane of the injector nozzle 30 or the swirl nozzle 31 for illustrative reasons.

The radially outer ends of the compressed air bores 300 and 301 are connected to an annular channel 304 surrounding the injector nozzle 30 and the compressed air bore 310, 311 and 312 of the swirl nozzle 31 are connected to an annular channel 315 surrounding this nozzle (FIG. 14). The two ring channels 304 and 315 are connected to one another by a line 320 and to the compressed air line 32 via a connecting line 321 and a changeover valve 90.

The take-off device 4 consists in the usual way of a driven take-off roller 45 and a pressure roller 450 which can be lifted off it and is pressed elastically against the take-off roller 45 (FIG. 2).

The spool 42 is driven by a winding roller 43. For oscillating laying of the thread 10 during winding, a traversing thread guide 46 is connected upstream of the winding device 41 in the usual way.

On its way between the swirl member 3 and the take-off device 4, the thread 10 is monitored by a thread monitor 91 for the presence of the spinning tension. The thread monitor 91 is connected in terms of control to the drive device 24 of the sliver clamping devices 240 and 241 in order to stop the sliver 1 in the event of a thread break while the drafting unit 2 continues to run. This operative connection 910 is shown as a line.

Immediately next to the thread run is in the vicinity of the twist 3 between this and the thread monitor 91, the mouth of a suction nozzle 92. This suction nozzle 92 has the task, with continuous spinning operation, loose fibers that leave the twist 3 as a flight, or in the event of a thread breakage to be sucked off from the drafting unit 2 in the form of a piece of thread which is supplied later.

Before going into the elements required for piecing, the function of the spinning device described above in the structure should first be explained:

During the undisturbed spinning process, a fiber sliver or a sliver 1 is fed to the drafting system. After leaving the drafting unit 2, the fiber material gets into the swirl element 3. By deflecting the edge regions of the warped fiber material between the rollers 23, 230 of the drafting system and the inlet opening 305 of the swirl element 3, the ends of the outer fibers spread out from the band-like fiber material.

The pneumatic swirl element 3 provides the core 100 of the thread 10 with a certain wrong twist, which is then largely reversed (see FIG. 3, zone IV). When false wire is distributed and when it is removed, the protruding fiber ends bind into the core 100 of the thread 10 to form loops 101 and in this way cause the spun thread 10 to have the desired strength, the position of the fiber ends relative to the finished thread 10 the hairiness of it determines.

The finished spun thread 10 is drawn off from the swirl member 3 by the take-off device 4 and fed to the bobbin 42 for winding, the thread 10 being monitored by the thread monitor 91 during the take-off.

In order to be able to automatically fix a thread break in the device described, additional elements are required, which are described below:

For the return of the yarn end 12 caused by a yarn break to the swirl member 3, the swivelable suction tube 93 can be delivered in a known manner to the bobbin 42, which can be lifted off the winding roller 43 (see position 93 '), the drive device 930 of which is only indicated schematically in FIG. 2. This suction pipe 93 is connected via a valve 932 to a vacuum source, not shown. An auxiliary drive roller 94, which can drive the coil 42 in the return delivery direction, can also be delivered to the coil 42 by means of a drive device 941 (see arrow 940 in FIG. 2).

The suction pipe 93 has on its side facing the swirl member 3 in a known manner a (not shown) slot through which the thread 10 can emerge when the suction pipe 93 is pivoted back from the position 93 'into the position shown in FIG. 2. A pair of auxiliary rollers 95, which is arranged on a pivotable holder 950, is assigned to the suction pipe 93 and the swirl element 3. This pair of auxiliary rollers 95 has the task of picking up the thread end 12 after it has partially left the suction tube 93 through the slot (see position 10 'in FIG. 2) and leading it in front of the outlet mouth 318 of the swirl element 3 (see position 95'). .

A thread reserve device 47 is located between the swirl member 3 and a thread monitor 91. This thread reserve device 47 has two thread guides 470 and 471, between which a thread deflection element 472 can be moved transversely to the chamfer run (see arrow 44). For this purpose, the thread deflecting element 472 is connected to a drive device 473.

In addition to the compressed air holes 300 and 301 or 310, 311 and 312 required for the spinning process, the injector nozzle 30 and the swirl nozzle 31 also have further compressed air holes 306 and 316 which, in contrast to the compressed air holes 300, 301, 310, 311 and 312, are not tangential , but open radially into the axial bore 302 or 313 (see Fig. 14) and are inclined opposite to the withdrawal direction (arrow 44), so that they impart a component of movement in the return direction when the thread end 12 is acted upon. These compressed air bores 306 are connected to an annular channel 307 and the compressed air bores 316 to an annular channel 317, which are connected to one another by means of a line 322. The latter is connected to the compressed air line 32 via a connecting line 323 and the changeover valve 90.

As shown in FIG. 1, a compressed air nozzle 60 is arranged on one side of the thread path between the swirl member 3 and the drafting unit 2, which is connected to the compressed air line 32 via a valve 900 and a connecting line 901. The compressed air nozzle is oriented essentially parallel to the clamping line of the rollers 23, 230 of the drafting unit 2. The compressed air nozzle 60 forms a thread feeder 6, as will be explained in more detail later.

With respect to the thread path defined by the axis of the swirl element 3, the suction opening 700 of a suction tube 70, which forms a pneumatic gripper 7, is located opposite the mouth 600 of the compressed air nozzle 60. This gripper 7 is in its receiving position in the position 7 'and is retractable with the aid of a drive device 71 next to the drafting device 2 in the direction oblique to its top rollers 200, 210, 220 and 230 up to the position shown in FIG. 1 (cf. Fig. 2).

If one imagines a plane E1 and E2 respectively laid down by the axes of the rollers 22, 220 and 23, 230 (see FIG. 2), then these planes E1 and E2 enclose an area B between them. In this area B, a thread insert 8 is provided which, according to FIGS. 1 and 2, consists of a hook 80 which can be moved essentially parallel to the rollers 22, 220 by means of a drive device 82 and which extends from the swirl element 3 on the Roll 230 crosses over to the suction tube 70 extending thread end 12. The arrangement of the path of movement of the thread insert 8 is now such that the thread end 12 is shifted laterally outside the sliver path between the straps 221, 222, ie on the side of the straps 222 facing away from the strappy 221, in such a way that the thread end 12 is passed through the roller 230 redirected becomes. As shown in FIG. 1, the thread end 12 is drawn so far into the drafting system 2 that the hook 80 is located essentially in the cross-sectional plane E3 through the drafting system 2 in the extension of the axial bores 302 and 313 of the swirl element 3.

Between the last two roller pairs 22, 220 and 23, 230 of the drafting unit 2, i.e. in area B, the thread layer 8 is assigned a thread brake 81, against which the thread end 12 can be brought into contact with the thread insert 8 during the insertion movement into the drafting system.

To generate the compressed air and suction air flows required for spinning and piecing, a vacuum source 96 (FIG. 1) is provided, with the pressure side of which the aforementioned compressed air line 32 is connected via a pressure line 960 and a valve 324. The suction nozzle 92 is connected to the suction side of the vacuum source 96 via a line 920 and the suction pipe 70 via a line 973, possibly via valves (not shown). Furthermore, the suction nozzle 25 is connected to the suction side of the vacuum source 96 via a line 250 and a control valve 902.

To control the piecing process, a control device 9 is provided, with which the elements working during the piecing process are connected in terms of control. 1 and 2, the corresponding operative connections between the control device 9 and the element to be controlled are shown as lines. These are the operative connection 942 for the drive device 941 of the auxiliary drive roller 94, the operative connection 931 for the drive device 930 and the operative connection 933 for the valve 932 of the suction pipe 93, the operative connection 451 for lifting the pressure roller 450 off the take-off roller 45, the operative connection 951 for the swivel drive of the holder 950 of the auxiliary roller pair 95, the operative connection 474 for the drive device 473 of the thread reserve device 47, possibly an operative connection to a valve (not shown), which is possibly provided in the line 920 leading to the suction nozzle 92 , the operative connection 325 to the valve 324 between the vacuum source 96 and the compressed air line 32, the operative connection 905 to the changeover valve 90 for switching the swirl member 3 from spinning mode to return delivery and back, the operative connection 904 to the valve 900 for controlling the compressed air nozzle 60, the operative connection 903 to the control valve 902 for the suction nozzle 25, the operative connection 72 to the drive device 71 for the gripper 7, optionally an operative connection to a valve (not shown) possibly provided in the line 73 for a gripper 7 designed as a suction pipe 70, the operative connection 83 to the drive device 82 for the thread insert 8 as well as the operative connection 242 to the drive device 24 of the two matched clamp devices 240, 241.

The operation of the device shown in Figures 1 and 2 is discussed below:

If a thread break occurs during the spinning process, the thread monitor 91 is addressed, which then actuates the sliver clamping devices 240 and 241 via the operative connection 910, whereby the fuse 1 is pressed against the rollers 200 and 210 and is thereby held back. These two rollers 200 and 210 are lifted off the driven rollers 20 and 21. The subsequent pairs of rollers 22, 220 and 23, 230, however, convey the fuse 1 further in the direction of the swirl element 3, as a result of which there is an intermediate the rollers 21, 210 and 22, 220 come to break the fuse 1. Due to the swirl member 3, which is still pressurized, this part of the fuse 1, which is still fed to the swirl member 3 by the drafting device 2, is spun into a short piece of yarn. Since this is not connected to the thread 10 wound on the bobbin 42, this short piece of thread is now sucked off by the suction nozzle 92.

Simultaneously with the actuation of the sliver clamping devices 240, 241, the thread monitor 91 effects means (not shown) that the bobbin 42 is lifted off the winding roller 43 and is thereby stopped. In addition, the lifting of the pressure roller 450 from the take-off roller 45 is effected in a manner not shown. Furthermore, the supply of compressed air to the swirl element 3 is prevented by means of the valve 324 and the suction effect on the suction nozzle 25 is prevented by means of the control valve 902.

Num is prepared with the help of the control device 9 for spinning. For this purpose, the changeover valve 90 is switched over and the valve 324 is brought into the flow-through position, so that a compressed air flow in the swirl member 3 is opposite to the withdrawal direction, i.e. opposite to arrow 44, is generated. The swirl element is cleaned by this compressed air flow, detached fibers and dirt components being removed by the suction nozzle 25.

The thread insert 8 is brought from the position shown in Fig. 1 into its position 8 '. If this is done, the gripper 7 is moved from the position shown in Fig. 1 to the position 7 '.

Subsequently, the auxiliary drive roller 94 takes over the support of the coil 42. The suction tube 93 is brought from the position shown in FIG. 2 into the position 93 'and a vacuum is generated in it by actuating the valve 932. The auxiliary drive roller 94 is now driven in the returning direction and rotates the spool 42 in the direction of arrow 940, so that, in accordance with the backward rotation of the spool 42 by the action of the suction air flow acting in the suction tube 93, the thread end 12 formed during thread breakage is unwound from the spool 42 and sucked off becomes. Now the suction tube 93 is moved back into the position shown in FIG. 2, whereby the thread end 12 exits the suction tube 93 from the slot (not shown) and assumes the position 10 '. The pair of auxiliary rollers 95 is now pivoted from a standby position, not shown, to position 95 ', taking hold of the thread end 12 located in position 10' and bringing it in front of the outlet mouth 318 of the swirl member 3 and thus into the effective range of the air flow acting in the swirl member 3 . A thread reserve of a defined size is formed in a manner not shown between the thread guides 470, 471 with the aid of the thread deflecting element 472. The auxiliary drive setpoint 94 and thus also the coil 42 are then stopped.

By means of cutting means, not shown, the thread 10 has been brought to a suitable length.

The further return delivery of the thread end 12 into the swirl member 3 takes place by turning back the auxiliary roller pair 95 and by releasing the previously formed thread reserve. The compressed air flow acting in the compressed air bores 316 and 306 of the swirl element 3 supports the return delivery of the thread end 12 in the direction of the drafting system 2. Now the valve 900 is actuated so that a compressed air stream also emerges from the compressed air nozzle 60, which is oriented transversely to the transport direction of the thread end 12 (opposite to arrow 44) and which detects the thread end 12 emerging from the inlet mouth 305 of the swirl member 3 and the feeds pneumatic gripper 7, which waits in the position 7 ', so that the compressed air flow blows the thread end 12 exactly into the suction opening 700 of the suction pipe 70.

The release of the thread reserve by means of the thread reserve device 47 takes place so slowly that the compressed air nozzle 60 is able to keep the thread end 12 leaving the inlet opening 305 always stretched while it is being fed to the gripper 7, which has a favorable influence on the attachment security and the appearance of the attachment.

The suction pipe 70 now sucks the thread end 12. As soon as the thread end 12 is held securely by the suction tube 70, the valve 324 is actuated and the compressed air supply to the swirl element 3 and to the compressed air nozzle 60 is thereby prevented in order to return the thread end 12 as gently as possible and to avoid untwisting the thread end 12.

After a sufficient length of thread has been sucked into the suction pipe 70, this is withdrawn from the position 7 'into the position shown in FIGS. 1 and 2. By a corresponding movement of the gripper 7 during its retraction movement from the position 7 'in the position shown, the thread end 12 is then pulled past the top roller 230 of the pair of exit rollers 23, 230 to next to the drafting device 2, the thread end 12 laterally for contact with the Top roller 230 of the drafting unit 2 arrives. Appropriate training of the upper roller 230, for example a chamfer (not shown), ensures that the thread end 12 is held in the clamping line region of the rollers 23, 230 regardless of the direction of movement of the hook 7 during further retraction and of the subsequent movement of the thread insert 8.

When the gripper 7 has reached its position shown in FIG. 1, the return delivery of the thread end 12 is ended. The thread end 12 assumes a defined position in the suction tube 70, since the returned length of the thread has been precisely measured beforehand by the thread reserve device 47.

The compressed air supply to the compressed air bores 316 and 306 is now cut off.

Num is the hook 80, which had previously been in the position 8 ', pulled into the position shown in Fig. 1. As shown in FIG. 2, the thread end 12 is fed to a thread brake 81 to form a loop 102 on the side of the apron 222 facing away from the roller 22 and is brought to bear against it.

Simultaneously, the spool 42 is driven again in the take-off direction (arrow 44) with the aid of the auxiliary drive roller 94 and the pressure roller 450 previously lifted off the take-off roller 45 is brought back into contact with the driven take-off roller 45, so that the thread end 12 is pulled through the swirl member 3 again becomes. In addition, the valve 324 is operated again and the changeover valve 90 is switched over. A first compressed air stream oriented in the withdrawal direction (arrow 44) thus acts in the swirl member 3, while a second compressed air stream acts transversely to the withdrawal direction (arrow 44). Now the fuse 1, which was previously stopped, is released by the fuse clamping devices 240, 241.

The compressed air flow of the compressed air nozzle 60 blows onto the thread end 12 located in the draw-off during this time and prevents the thread end 12 from entraining individual fibers. The blown-off fibers are collected and sucked off by the suction pipe 70. For this purpose, the suction pipe 70 has been brought back into its position 7 'after performing the insertion movement of the thread insert 8 in the position shown in Fig. 1.

After a certain time, which is determined by the control device 9, this compressed air flow in the compressed air nozzle 60 is switched off by actuating the valve 900, whereupon the suction pipe 70 can also return to its initial position shown in FIGS. 1 and 2. This time is determined by the control device 9 so that the thread end 12 has been drawn out of the drafting device 2 to a predetermined length.

After the compressed air flow in the compressed air nozzle 60 has been switched off, a compressed air flow in the withdrawal direction (arrow 44) is generated in the swirl element 3 by actuating the valve 324 and the reversing valve 90. Now also the fuse 1 comes together with the thread end 12 into the swirl member 3 and is incorporated into the swivel member 3 in the thread end 12, so that a new thread 10 is now spun from the fuse 1 after the beginning of the match in the thread end 12.

The hooking on the thread brake 81 hook 80 and the thread brake 81 together form an elastic thread clamp which brakes the thread end 12 during thread take-off, so that the thread end 12 cannot jump together even after being released by the gripper 7 and thus not in a curled form , ie undrawn state can get into the clamping line of the rollers 23, 230 and in the swirl element 3. This ensures a perfect piecing.

The suction nozzle 25 is directed onto the lower roller 23 of the pair of outlet rollers 23, 230 of the drafting unit 2 and therefore has no or only an insignificant effect in the area of the thread path between the drafting unit 2 and swirl element 3. Control of the suction nozzle 25 can therefore generally be dispensed with. If the suction air nozzle 25 was nevertheless switched off during the piecing process by means of a valve (not shown), it can now be switched on again, so that these loose fibers, which could have got stuck on the roller 23 of the drafting unit 2, are sucked off by the latter. A cleaning suction or brush can also be assigned to the top roller 230.

The function of the compressed air nozzle 60 after reinstalling the thread take-off is explained in more detail below with reference to FIGS. 3 and 4:

The beginning of a fuse 1 which was previously clamped by a sliver clamping device 240, 241 always has an irregular appearance. There is a build-up of material here that is not desired in piecer 11. The compressed air nozzle 60, when it is switched on after reinstalling the thread take-off, therefore has the task of blowing off the excess material from the thread end 12.

FIG. 3 shows the piecing device 11 without the compressed air nozzle 60 being able to take effect when it is removed again, while the piecing device 11 according to FIG. 4 was formed with the aid of the compressed air nozzle 60.

As shown in FIG. 3, the piecer 11 can be divided into three zones I, II and III, to which the normally spun thread 10 is connected as zone IV:

In zone I, all the fibers arriving in the swirl member 3 are wound in loose spirals around the stretched thread end 12 by the swirl action of the injector nozzle 30. The Thread spun in Zone I is therefore not very strong, so that there is a risk of deferment.

In zone 11, the fiber stream forms a core 13, which lies almost parallel to the thread end 12. A smaller part of the fibers forms the wrapping fibers (loops 101), which loop around both cores (thread end 12 and new fiber material). The length of this zone 11 determines the strength of the piecer 11.

Due to the fact that it is no longer clamped between the rollers 23, 230 of the drafting unit 2 at the moment of binding, the thread end 12 is no longer bound in the stretched position in the newly created thread in zone III.

Zone III is followed by zone IV, in which the thread 10 consists exclusively of fibers which are fed to it from the drafting device 2.

If, after the thread take-off is switched on again, the compressed air nozzle 60 is first activated for a certain period of time, as shown in FIG. 4, this eliminates the fibers loosely wrapped around the yarn end 12 (zone I). There is only a relatively small amount of fiber accumulation here, since approx. 90% of the fibers supplied by the drafting device 2 are removed by the compressed air nozzle 60.

Since the action of the compressed air nozzle 60 cannot be switched off suddenly due to the length of the lines 32 and 321, the compressed air nozzle 60 also acts into zone II of the piecing 11. Fibers are then also blown off here, which makes the mass profile of the piecing 11 more favorable. Zone II is similar to Zone II from FIG. 3. Zone III is also the same in the two methods described (see FIGS. 3 and 4).

The compressed air nozzle 60 is switched off completely at the latest when the thread end 12 previously returned for spinning leaves the rollers 23, 230 of the drafting unit 2 in order to avoid that a thin spot in the new thread 10 arises after zone III.

In the above-described method, in which the thread take-off begins before the fuse 1 is released again, there is the disadvantage that the piecing 11 is followed by a thread section which has been formed from an inexactly distorted length section of the fuse 1, since it is always it takes a certain time until the delayed fuse 1 is regular again. In order to avoid that this length section of the fuse 1 reaches the piecing 11, the piecing is carried out as follows according to a modified method (see also FIG. 5):

After the return of the thread end 12 to the gripper 7, the fuse 1 241 released (t _o), by operating the Luntenklemmvorrichtungen 240. The beginning of the sliver leaving the rollers 23, 230 is sucked off by the suction nozzle 25. Simultaneously or shortly after the fuse 1 is released, the bobbin 42 is lowered onto the winding roller 43 (t 1). Then the gripper 7 is brought from its position 7 'in its position shown in Fig. 1 next to the drafting device 2 and the pressure roller 450 back to the driven take-off roller 45 (t₂). Subsequently, the thread end 12 already in the take-off is inserted into the pair of outlet rollers 23, 230 and brought into contact with the thread brake 81 with the help of the thread insert 8 (t₃).

Now the compressed air nozzle 60 is temporarily brought back into effect so that entrainment of the fuse 1 as well as of loose fibers by the thread end 12 located in the take-off is excluded with certainty (t₄, t₅). The Fuse 1 and the fibers blown off from the thread end 12 are sucked off through the suction nozzle 25 and / or the suction pipe 70 brought back into position 7 '. After the compressed air nozzle 60 is deactivated again, a compressed air flow in the withdrawal direction (see arrow 44) is finally generated by actuating the valve 324 and the reversing valve 90 in the swirl element 3.

The release time for the fuse 1 and the switch-on time for the thread take-off are coordinated with one another by the control device 9 such that the thread end 12 only reaches the rollers 23, 230 of the drafting device 2 after the length section of the fuse 1, which is caused by the stop of the fuse 1 had suffered when the thread breakage occurred, was sucked off through the suction nozzle 25.

As the above description shows, a multitude of elements are only required for piecing, but not for the normal spinning process. These are, in particular, the control device 9 and the auxiliary drive roller 94 controlled by this, the suction tube 93, the auxiliary roller pair 95, the thread reserve device 47, the compressed air nozzle 60, the gripper 7 and the thread insert 8 and the thread brake 81 assigned to this thread insert 8. It is therefore possible and advantageous to place these elements on a maintenance device 97 (see FIG. 2) which controls the piecing process. This maintenance device 97 can be moved along a large number of similar spinning positions A, B, C, ... (see FIG. 12) of the machine and, at any desired spinning position A, B, C, ..., corrects such a thread break.

14, the nozzles of the swirl element 3 (injector nozzle 30, swirl nozzle 31) arranged one behind the other in the take-off direction (arrow 44) are arranged at an axial distance from one another and form a gap 34 between them. In the pneumatic return of the thread end 12 by the Swirl element 3 through there is therefore the risk that the end leading in this return delivery will get caught on the outlet side of injector nozzle 30. In order to rule out this danger, it is provided that a stronger air flow in the return delivery direction is generated in the injector nozzle 30 than in the swirl nozzle 31. This can be done by a correspondingly stronger orientation of the compressed air bores 316 in the return delivery direction (opposite to arrow 44) compared to which the compressed air bores 306 have a smaller component in the return delivery direction. According to the exemplary embodiment shown in FIG. 14, the return air flow is throttled more in the swirl nozzle than in the injector nozzle 30. For this purpose, as shown in FIG. 14, the compressed air bores 306 in the injector nozzle 30 have a larger diameter than the compressed air bores 316 in the swirl nozzle 31. The same effect can also be achieved by a different number of compressed air bores 306, 316 in the injector nozzle 30 and in Swirl nozzle 31 can be reached.

The pneumatic return of the thread end 12 can alternatively also take place, if desired, with the aid of a compressed air nozzle (not shown) which can be delivered to the outlet mouth 318.

So that regardless of the fiber material to be spun or the thread size, it is always ensured that the thread leaving the inlet mouth of the swirl element 3 is also properly fed to the gripper 7, this thread pattern is carried out according to FIG. 1 with the aid of a compressed air nozzle 60, the mouth 600 of which has an inside diameter with constant Has cross-section. A laminar flow of compressed air is generated in this way.

If the slow return delivery of the thread end 12 to the compressed air nozzle 60 takes place through a corresponding reverse rotation speed of the auxiliary roller pair 95, the thread reserve device 47 can be dispensed with.

If a thread reserve device 47 is used, the thread guide 470 can be omitted if the swirl member 3 takes over its task.

In order to achieve a safe and gentle supply of the thread end 12 to the gripper 7 so that the thread end 12 does not dissolve in the air stream, the compressed air stream leaving the compressed air nozzle 60 is set as weak as possible, especially when the gripper 7 operates pneumatically. For blowing off fibers and for restraining the fuse 1 from the thread end 12 located in the draw-off, on the other hand, it is advantageous if the compressed air flow is stronger. For this reason, the compressed air nozzle 60 is assigned a device for optionally applying a lower overpressure during the return of the thread and a higher overpressure at the start of the thread withdrawal. This device can be formed by a changeover valve, which connects the compressed air nozzle 60 alternately with different pressure sources, or also by the valve 900, if this is designed as a throttle element and can also assume an intermediate position in addition to the closed and the open position.

In the interest of a gentle feeding of the thread end 12 to the hook 7, it is appropriate to leave the compressed air nozzle 60 on only until the return delivery by the swirl member 3 has ended and, if possible, even switch off earlier after the hook 7 the thread end 12 has grasped safely. For this purpose, both the swirl element 3 and the compressed air nozzle 60 according to FIG. 1 are connected upstream of a common control valve 324.

In order to ensure when feeding the returned thread 10 to the gripper 7 that the thread end 12 cannot lie against one of the rollers 23, 230 of the drafting unit 2, the swirl element 3 is designed according to FIG. 9. As this figure clearly shows, the swirl element has on its inlet side 308 an axial projection 309 which receives the inlet mouth 305 of the swirl element 3. The compressed air nozzle 60 is arranged in such a way to the projection 309 of the swirl element 3 that the compressed air stream leaving the compressed air nozzle 60 touches the end face of the projection 309 of the swirl element 3. When viewed in the direction of the compressed air flow, turbulence occurs behind the axial projection 309 of the swirl element 3, which deflect the thread end 12 in the direction of the swirl element 3 and thereby remove it from the rollers 23, 230.

It has been shown that particularly good spinning results are achieved if the swirl member 3 is arranged as close as possible to the rollers 23, 230 of the drafting unit 2. To make this possible, according to FIGS. 9 and 10, the compressed air nozzle 60 is at least partially in the gusset 231 of the rollers 23, 230 of the drafting device 2 facing the swirl element 3. In order to prevent the accumulation of flight on the top roller 230, it has have proven to be advantageous if the compressed air nozzle 60 is at a distance a of 1 mm from the top roller 230 of the drafting unit 2.

As previously explained in connection with FIG. 3, the fibers are looped around the core 100 of the thread 10 by the injector nozzle 30. This balloon twist is identified by arrow 303 in FIG. 7b. However, the yarn core receives a core rotation in the swirl nozzle 31 (see arrow 319), which is opposite to the balloon rotation (see arrow 314) in the swirl nozzle 31. To be a special one 6 and 7a, 7b, it is provided that the compressed air nozzle 60 is arranged tangentially to the thread end 12 extending from the drafting device 2 to the swirl member 3 and the core rotation (arrow 319) of the thread end 12 is opposite. Since this core rotation is brought about by the compressed air bores 310, 311 and 312, the compressed air nozzle 60 is - as shown in FIG. 7a - directed in the circumferential direction in which these compressed air bores 310, 311 and 312 open into the axial bore 313 of the swirl nozzle 31. As a comparison of FIGS. 7a and 7b with FIG. 8 shows, such a tangential arrangement of the compressed air nozzle 60 is not only possible if the swirl member 3 viewed in the thread take-off direction (see arrow 44) two rows of compressed air bores 300, 301 and 310, 311 and 312, but also in swirl devices with a single row of compressed air holes 330, 331. In the first case, the core rotation (arrow 319) is always through the second nozzle (swirl nozzle 31) with the second row of compressed air holes 310, 311 and 312, which for this purpose also acts to a greater extent on the thread end 12 (three compressed air bores 310, 311, 312 compared to two compressed air bores 300, 301 in the injector nozzle). However, if the swirl member 3 has only a single row of compressed air holes 330, 331, these compressed air holes cause both the balloon rotation (see arrow 332) and the core rotation (see arrow 319). In this case, the compressed air nozzle 60 is thus directed against the circumferential direction of the air flow in the swirl element 3 caused by the compressed air bores 330, 331.

This orientation of the compressed air stream leaving the compressed air nozzle 60 results in a particularly good detachment of loose fibers from the thread end 12 located in the tongue and particularly good retention of the fuse 1 fed to the suction nozzle 25.

It is not absolutely necessary, although particularly advantageous, for the suction opening 700 of the suction pipe 70 to face the compressed air nozzle 60. In particular in the case of a mechanical design of the thread feeder 6, it may well be expedient if the suction mouth 700 of the suction pipe 70 is provided concentrically with the axis of the suction pipe 70.

A designed as a suction tube 70 gripper 7 can also remain in its position 7 'during the entire piecing process if the suction tube 70 has a - possibly controllable - longitudinal slot (not shown) through which an intermediate section of the returned thread end 12 can emerge to get into the path of movement of the thread insert 8.

If it is mentioned in the above description that the gripper 7 is retracted as far as the drafting system 2, this does not only mean a retraction of the gripper 7 to the side of the drafting system (according to FIG. 12). This should also be understood to mean another withdrawal of the gripper 7 outside of the drafting unit 2, for example above it, i.e. on the side of rollers 200, 210, 220 and 230 facing away from rollers 20, 21, 22 and 23.

If the thread end 12 is inserted into the pair of outlet rollers 23, 230 by means of a corresponding shaping and / or movement of the gripper 7, the thread feeder 8 can also be dispensed with. Depending on the design of the gripper 7, the thread brake 8 can also be dispensed with, in particular if the gripper 7 is of a mechanical design, or can also be arranged in the gripper 7 if it is of a pneumatic design. It is advantageous if such a thread brake 81 is only effective when the thread is being drawn off again.

The insertion of the thread end 12 into the clamping line of the rollers 23, 230 of the drafting device 2 can be ensured by a corresponding arrangement and / or retraction movement of the gripper 7, the threading of the thread end 12 in the clamping line being supported by a chamfering of the peripheral edge of the roller 230 can. Alternatively, one or more notches 232 can also be provided in the edge facing the gripper 7 between the lateral surface and the end surface of the roller 23. These notches 232 grip the inclined thread end 12 and then pull it into the nip line between the rollers 23, 230.

In order to make it even easier to insert the thread end 12 into the clamping line of the rollers 23, 230 of the drafting unit 2 when the gripper 7 is pulled back and / or during the insertion movement of the thread insert 8, it is expedient if the upper roller 230 is assigned a thread guide 26. This thread guide ensures that the thread end 12 is held in the half of the upper roller 230 facing the clamping line of the pair of outlet rollers 23, 230, regardless of the movement path of the gripper 7, and thus cannot reach the area of the upper half of the upper roller 230, whereby an insertion into the nip line of the rollers 23, 230 would not be possible.

Such a thread guide can be designed differently. In a simple embodiment, this thread guide according to FIGS. 1, 2 and 6 is designed in the form of an essentially cylindrical projection 260 of the roller 230. This projection 260 faces the path of movement of the gripper 7 and has a diameter d that is smaller than the diameter D of the roller 230 (see FIG. 6).

Alternatively, instead of a cylindrical projection 260 of the roller 230, a thread guide 26 can also be provided, which has the shape of a bracket 261 (see FIG. 12). If desired, such a bracket can also be arranged on a maintenance trolley 97 (see dash-dotted illustration in FIG. 2), since this thread guide is only required during the piecing process.

In order to ensure that the returned thread end 12 is held securely by the pneumatic gripper 7, it is advantageous if the returned thread length is longer than required and the thread length required for piecing is only determined after the thread return has been completed. For this purpose, according to FIG. 1, a suction device 70 is assigned a cutting device 74, which brings the thread 10 extending in the suction pipe 70 to a desired length by controlling the control device 9 (see operative connection 740). For example, this cutting process can take place after the suction pipe 70 has reached its position shown in FIG. 2, but the thread insert 8 has not yet started its insertion movement.

It is advantageous if you can determine the piecing length. This is particularly advantageous because different minimum lengths are required for the piecing device 11 depending on the material and yarn thickness. For this reason, a thread monitoring device 75 is assigned to the suction pipe 70 according to FIG. 1, which is connected to the control device 9 in terms of control (see operative connection 750). In this way, the thread monitoring device 75, which is designed as a light barrier according to FIG. 1, can emit a signal to the control device 9 when the thread end 12 passes this thread monitoring device 75. In the control device 9 there is a timer, not shown, which can be set to different values and which controls the compressed air nozzle 60.

As FIG. 1 shows, a gripper 7 designed as a suction pipe 70 does not need to be assigned a control valve for controlling the negative pressure prevailing in it. However, if the vacuum effect is to be controlled, it is important in order to achieve a sufficient retention force for the thread end 12 when it is inserted into the drafting device 2 that the vacuum is only switched off after this insertion of the thread end 12. As mentioned, this insertion of the thread end 12 into the drafting unit 2 takes place through the retraction movement of the suction pipe 70 and at the latest through the movement of the thread insert 8.

The thread brake 81 can be a retention set, e.g. in the manner of a burdock covering. However, as described, the thread brake 81 can also form an elastic thread clamp together with the thread insert 8 and for this purpose have a resilient clamping surface against which the thread insert 8, which for this purpose is connected to its drive device 82 via a spring (not shown) is brought into elastic contact. The resilient clamping surface of the thread brake 81 can consist of soft rubber, felt or the like.

The above description shows that the described method and the described device can be modified in a variety of ways within the scope of the present invention, for example by replacing individual features with equivalents or using them in other combinations. So it is not necessary to lift the pressure roller 450 for the insertion of the thread 10 from the take-off roller 45, if insertion of the thread into the take-off device 4 can be ensured in another way by guide elements and a suitable design of the pressure roller 450. It is also not absolutely necessary for threading or for grasping the thread end 12 to apply pneumatically working elements. Furthermore, it is possible to replace the thread insert 8, which is designed mechanically according to FIG. 1, and the mechanical thread brake 81 by pneumatic elements. Such an embodiment of the device is explained below with reference to FIG. 12.

In the exemplary embodiment shown in FIG. 12, the thread feeder 6 is designed mechanically, namely as a pin 61, which can be moved transversely to the elongated axis of the swirl element 3 essentially parallel to the rollers 23, 230. This pin 61 has a retention set 610 on its outer circumference, which is designed, for example, like a Velcro. After the thread end 12 has left the swirl member 3 when it is returned, this thread end 12 is carried by the pin 61 during its movement from the position shown in FIG. 12 into its position 61 '. In order to ensure that the thread end 12 is securely received by the restraining assembly 610, the pin 61 can, if desired, also be given a slight rotary movement.

Since the feed speed to the gripper 7 depends on the displacement speed of the thread feeder 6 in a mechanical configuration of the thread feeder 6, a thread reserve device 47 can be omitted.

According to FIG. 12, the gripper 7 is not designed as a suction pipe 70, but has a pair of rollers 76. After the pin 61 has reached its position 61 ', the gripper 7 with its pair of rollers 76 is brought into its position 7', which is ensured by a suitable relative movement between the gripper 7 and pin 61 or by thread guides, not shown, that the returned thread enters the nip area of the pair of rollers 76.

After the thread end 12 is held securely by the pair of rollers 76, the gripper 7 is brought back from its position 7 'into its initial position shown in FIG. The pair of rollers 76 reaches the area of a suction nozzle 77 which sucks in the free end of the thread end 12 held by the pair of rollers 76. If necessary, a thread cutting device (not shown) can also be assigned to this suction nozzle 77.

In the embodiment shown in FIG. 12, a compressed air nozzle 84 serves as the thread insert, while a sieve 85, which is subjected to a negative pressure via a suction pipe 850, serves as the thread brake. This sieve also supports the work of the compressed air nozzle 84 when inserting the thread end 12, the thread length required for this being released by turning back the pair of rollers 76.

It is of course also possible to provide a mechanically designed gripper 7 in combination with a mechanical thread insert 8 and a mechanical thread brake 81, it may be sufficient if the clamping pressure of the pair of rollers 76 is so low that the movement of the thread insert 8 and the Pulling-off movement of the thread 10 is sufficient to pull the thread end 12 out of the roller pair 76 without opening or turning it back.

11 and 13 show further modifications of the device described above, in which the return of the thread end 12 through the swirl member 3 into the working area of the thread feeder 6 is not carried out with the aid of a compressed air flow, but in which a mechanical threading element 5 is used for this purpose is provided.

According to the exemplary embodiment shown in FIG. 11, the threading element 5 is designed as a clamp and consists of two parts 50 and 51 which can be moved relative to one another are. The two parts 50 and 51 have mutually facing guide surfaces 500 and 510, while their other peripheral surfaces 501 and 511 are adapted to the shape of the axial bore 302, 313 of the swirl element 3. For receiving the thread end 12, the part 50 of the threading element 5 has on its side facing away from the part 51 a longitudinal groove 502 which merges into a transverse groove 503 at its end facing the inlet opening 305 of the swirl element 3.

11 shows the threading element 5 in its release position. This figure shows that the part 51 of the threading element has a recess 512 essentially in the extension of the transverse groove 503. This recess 512 is adjoined in the axial direction with respect to the part 51 by a clamping surface 513 which can be brought to bear against the end surface 504 of the part 50 of the threading element 5, but does not extend into the region of the longitudinal groove 502.

The thread end 12 is received in a manner not shown by the threading element outside of the swirl element 3, for example from its position 10 'shown in Fig. 2'. The thread end 12, which has been brought to a predetermined length for this purpose so that it does not protrude beyond the recess 512, is held clamped between the clamping surface 513 and the end surface 504 of the threading element 5. The threading element 5 is now inserted axially into the swirl member 3 from the exit side of the swirl member 3 until it protrudes from the inlet mouth 305 of the swirl member 3. The part 50 is stopped so that its end face 504 is essentially at the level of the entry side 308 of the swirl element 3. The part 51 is moved a little further, so that the free end of the thread end 12 is released by the clamping surface 513. When the compressed air nozzle 60 is acted upon with excess pressure, the free end of the thread end 12 is blown out of the threading element 5 in the direction of arrow 62 and fed to the gripper 7 when a further thread length is brought into the effective range of this compressed air stream leaving the compressed air nozzle 60 through the longitudinal groove 502. As soon as the thread end 12 has been gripped by the gripper 7, the threading element 5 can be withdrawn without the thread end 12 being taken along.

According to the exemplary embodiment shown in FIG. 13, the threading element 5 is designed as a brush 52. This brush 52 is pivotally mounted on a holder 520 so that it can be brought into the position 52 'shown in position 10' for receiving the thread end 12 in position 10 and then to be brought back into the position in which it is in Extension of the axial bore 302, 313 of the swirl element 3 is located. The brush 52 can thus be introduced into the swirl element 3 by an axial movement until the free end projects beyond the inlet side 308 of the swirl element 3 facing the drafting device 2.

When the brush 52 is in its position 52 ', the thread end 12 is taken from the position 10', which can be supported by a corresponding rotational movement of the brush 52. The brush 52 takes over the position 10 'occupying the thread end 12 in such a position that the thread end 12 is located at the free end of the brush 52 so that it is easily removed by inserting the brush 52 into the swirl organ by the thread feeder 6 can be. 13, this thread feeder 6 is therefore designed mechanically.

After the thread end 12 has been picked up by the thread feeder 6 and / or the gripper 7, the brush 52 can be pulled out of the swirl member 3 again, the thread end 12 being prevented by the thread feeder 6 or the gripper 7 from following the brush.

In order to reduce the friction between the thread end 12 and the brush 52 during its retraction movement, a stripper 53 is assigned to the brush 52 according to the exemplary embodiment shown in FIG. 13, which by its design causes the thread end 12 to be lifted out of the brush 52. During the insertion and withdrawal movement of the brush 52 into and out of the swirl element 3, the brush 52 cleans the axial bore 302, 313 of the swirl element. In this way it is ensured that deposits that could have formed in the swirl member 3 are removed during the piecing process.

Claims (50)

1. A method of joining the thread [in] a spinning device operatin with a pneumatic twisting means, in which [method] a thread end is delivered from the outlet side back through the twisting means to a drawing unit and then inserted sideways into the pair of delivery rollers of the drawing unit, from where it is drawn off in the form of a continuous thread through the twisting means, while a roving is tied up, characterized in that the thread end is conveyed through the twisting means to the inlet side thereof, the twisting means being disposed behind the pair of delivery rollers of the drawing unit, and is gripped there and supplied to a gripper which is disposed beside the drawing unit and then pulls the thread end past the pair of delivery roller to beside the drawing unit for subsequent insertion into the said pair of delivery rollers.

2. A method according to Claim 1, characterized in that the thread end delivered back through the twisting means is subjected to a compressed air stream directed substantially parallel to the nip line of the pair of delivery rollers, in order to supply it to the gripper.

3. A method according to Claim 2, characterized in that the thread end delivered back through the twisting means is supplied to the gripper with the aid of a laminar stream of compressed air.

4. A method according to Claim 2 or 3, characterized in that before the thread end is delivered back through the twisting means a reserve of thread is built up and is then, during the return of the thread end through the twisting means into the stream of compressed air acting transversely to the travel of the thread, released sufficiently slowly for the thread end to be held stretched by the stream of compressed air while being supplied to the gripper.

5. A method according to one or more of Claims 2 to 4, characterized in that the compressed air stream is switched off as soon as the thread end has been gripped by the gripper.

6. A method according to one or more of Claims 2 to 5, characterized in that after the thread take up has been resumed, the thread end and the roving between the twisting means and the pair of delivery rollers of the drawing unit are subjected to a compressed air stream directed substantially parallel to the nip line of the paire of delivery rollers.

7. A method according to Claim 6, characterized in that the compressed air stream switched on after resumption of the thread take-up is switched off before the thread end leaves the pair of delivery rollers.

8. A method according to one or more of Claims 2 to 7, characterized in that the compressed air stream is directed tangentially against the rotation of the core of the thread extending from the drawing unit to the twisting means.

9. A method according to one or more of Claims 6 to 8, characterized in that a much weaker stream of compressed air is brought to bear on the thread end during the return thereof than after resumption of thread take-up.

10. A method according to one or more of Claims 1 to 9, characterized in that the twisting means is cleaned before or during the return of the thread end.

11. A method according to one or more of Claims 1 to 10, characterized in that the thread end is conveyed by a compressed air streams from the outlet side of the twisting means through the twisting means into the region of the compressed air stream acting transversely to the travel of the thread.

12. A method according to Claim 11, characterized in that during the pneumatic return of the thread end through the twistin means, the compressed air stream directed transversely to the path of the thread operates only as long as the compressed air stream effecting the return of the thread is operative in the twisting means.

13. A method according to one or more of Claims 1 to 12, characterized in that the gripper operates pneumatically and a negative pressure is produced in it at least until the thread end has been inserted into the drawing unit.

14. A method according to one or more of Claims 1 to 13, characterized in that the thread end, after being drawn to beside the drawing unit, is drawn in the form of a loop into the region between the last two pairs of rollers of the drawing unit.

15. A method according to Claim 14, characterized in that the thread end, when being drawn in the form of a loop into the region between the last two pair of rollers of the drawing unit, is brought into the area of action of a thread brake.

16. A method according to one or more of Claims 1 to 15, characterized in that the thread end during insertion into the drawing unit is brought into the area of the nip line of the pair of delivery rollers.

17. A method according to one or more of Claims 1 to 16, characterized in that the twisting means is cleaned by a first compressed air stream orientated in the direction from the oultet side of the twisting means to the inlet side thereof, the thread end is then subjected to this first compressed air stream in order to return it to the inlet side of the twisting means in order to be exposed there to a second compressed air stream which acts transversely to the direction of conveyance of the thread end and which supplies the thread end to a gripper which then pulls the thread end past the pair of delivery rollers to beside the drawing unit, whereupon the previously stopped roving is released and removed by suction from between the drawing unit and the twisting means, after which the thread end extending to the gripper is supplied in the form of a loop to a thread brake in the area between the last two pairs of rollers of the drawing unit, and is inserted into the pair of delivery rollers of the drawing unit and again subjected to take-up and simultaneously the second compressed air stream is again switched on to prevent the roving and loose fibre being sucked into the twisting means, the suction of the roving and the second compressed air stream are switched off before the thread end reaches the pair of delivery rollers of the drawing unit, and finally the excess spinning pressure operative in the take-up direction is brought to bear in the twisting means.

18. A method according to one or more of Claims 1 to 16, characterized in that the twisting means is cleaned by a first compressed air stream operating against the direction of take-up, the thread end is then subjected to the said first compressed air stream and conveyed thereby from the outlet side of the twisting means to the inlet side of the twisting means, where it is exposed to a second compressed air stream which acts transversely to the direction of conveyance and conveyed thereby to a gripper which then pulls the thread end past the pair of delivery rollers to beside the drawing unit, the thread end extending to the gripper is then supplied in the form of a loop to a thread brake in the region between the last two pairs of rollers of the drawing unit and is inserted in the pair of delivery rollers of the drawing unit, whereupon the thread end is again subjected to take-up, the previously stopped roving isthen released, while the second compressed air stream is again switched on to prevent loose fibres being sucked into the twisting means, and when the thread end has been taken up from the drawing unit spart from a predetermined length, the second compressed air stream is switched off, and finally the excess spinning pressure operative in the take-up direction is brought to bear in the twisting means.

19. A device for working the method according to one or more of Claim 1 to 18, comprising a pneumatic twisting means, a return element for returning the thread end from the oultet side of the twisting means to the inlet side thereof, and a gripper for pulling the thread end back from the inlet side of the twisting means past the pair of delivery rollers to beside the drawing unit, characterized by a thread feeder (6) for gripping the thread end (12) as it leaves the inlet end of the twisting means (3) during its return and supplying it to the gripper (7).

20. A device according to Claim 19, characterized in that the thread feeder (6) is in the form of a compressed air nozzle (60) disposed substantially parallel to the nip line of the paire of delivery rollers (23, 230) and having its mouth (600) facing the gripper (7) and disposed on the side of the twisting means (3) opposite to the gripper (7).

21. A device according to Claim 20, characterized in that the twisting means (3) has an axial projection (309) at its inlet side and the compressed air nozzle (60) is diposed relative to the twisting means (3) so that the compressed air stream leaving the compressed air nozzle (60) touches the front of the projection (309).

22. A device according to Claim 20 or 21, characterized in that the compressed air nozzle (60) is disposed at least partly in the nip (231) of the pair of delivery rollers (23, 230) of the drawing unit (2) facing the twisting means (3).

23. A device according to Claim 22, characterized in that the compressed air nozzle (60) is set at a distance (a) of a least 1 mm from the top roller (230) of the pair of delivery rollers (23, 230) of the drawing unit (2).

24. A device according to one or more of Claims 19 to 23, characterized in that the mouth (600) of the compressed air nozzle (60) has an inner diameter of constant cross-section.

25. A device according to one or more of Claims 19 to 24, comprising a twisting means having one or more compressed air bores for rotating the core of the thread and opening tangentially into the interior of the twisting means, characterized in that the compressed air nozzle (60) is disposed tangentially to the thread end (12) extending from the drawing unit (2) to the twisting means (3) and is directed against the direction of flow of the compressed air bore for rotating (319) the core of the thread end (12), the flow being produced by the compressed air bores (310, 311, 312; 330, 331) in the twisting means (3).

26. A device according to Claim 25, comprising a twisting means having a single row of compressed air bores opening tangentially into the axial bore of the twisting means, characterized in that the compressed air nozzle (60) is disposed tangentially to the prolonged axial bore of the twisting means (3) in the opposite direction to the flow direction of the compressed air flow leaving the compressed air bores (330, 331).

27. A device according to Claim 25, comprising a twisting means having two rows of compressed air bores one behind the other in the thread take-up direction, one row opening in one peripheral direction and the other row in the opposite peripheral direction tangentially into the axial bore of the twisting means, characterized in that the compressed air nozzle (60) is disposed tangentially to the prolonged axial bore (302, 313) of the twisting means (3) in the opposite direction to that peripheral direction in which the compressed air bores (310, 311, 312) of the second row in the thread take-up direction open into the axial bore (313) of the twisting means (3).

28. A device according to one or more of Claims 19 to 27, characterized in that the compressed air nozzle (60) is associated with a device (900) for optionally stressing with a higher or a lower excess pressure.

29. A device according to one or more of Claims 19 to 28, characterized in that the compressed air nozzle (60) is associated with a control device (9) and the gripper (7) is associated with a thread monitor (75) connected to the said control device (9).

30. A device according to one or more of Claims 19 to 29, characterized in that in addition to compressed air bores (300, 301, 310, 311, 312) to which an excess pressure is applied during the spinning process and which have a component in the take-up direction (44), the twisting means (3) comprises further compressed air bores (306, 316) to which an excess pressure is applied during the return of the thread and which have a component in the return direction.

31. A device according to Claim 30, comprising a twisting means comprising, disposed one behind the other in the thread take-up direction, an injector nozzle and a twisting nozzle separated therefrom by a gap, characterized in that both the injector nozzle (30) and the twisting nozzle (31) have at least one compressed air bore (306, 316) in the return direction, and a stronger air stream can be generated in the injector nozzle (30) than in the twisting nozzle (31).

32. A device according to Claim 31, characterized in that the compressed air bore (306) in the injector nozzle (30) has a larger diameter than the compressed air bore (316) in the twisting nozzle (31).

33. A device according to one or more of Claims 30 to 32, characterized in that compressed air bores (306, 316) of the twisting means (3) for the pneumatic return of the thread end (12) share a supply line (32) and a control valve (324) with the compressed air nozzle (60).

34. A device according to one or more of Claims 19 to 33, characterized by mechanical treating element (5) for returning the thread end (12) into the stroke region of the thread feeder (6).

35. A device according to Claim 34, characterized in that the threading element (5) is in the form of a clamp.

36. A device according to Claim 35, characterized in that the threading element (5) is in the form of a brush (52).

37. A device according to Claim 36, characterized in that the brush (52) is associated with a stripper (53).

38. A device according to one or more of Claims 19 to 37, characterized by a thread reserve device (47) disposed at the outlet side of the twisting means (3) and having a drive (473) which drives the thread reserve device (47) sufficiently slowly for the thread end (12) leaving the inlet mouth (305) of the twisting means (3) to be stretched by the thread feeder (6) while being supplied to the gripper (7).

39. A device according to one or more of Claims 19 to 38, characterized in that the gripper (7) is constructed as a suction air nozzle (70).

40. A device according to Claim 39, characterized in that the suction air nozzle (70) has a suction opening (700) facing the thread feeder (6).

41. A device according to one or mor of Claims 19 to 40, characterized in that the gripper (7) is movable from a receiving position (7′) in which it cooperates with the thread feeder (6), into an insertion positiion beside the drawing unit (2).

42. A device according to one or more of Claims 19 to 41, characterized by a thread inserter (8) movable from a standby position (8′) beside the drawing unit (2) into an insertion position in such a manner that it intersects the path of the thread end (12) extending from the twisting means (3) to the gripper (7) and during its subsequent motion introduces the thread end into the drawing unit (2).

43. A device according to Claim 42, characterized by a thread brake (81) to which the thread end (12) can be supplied when being inserted into the drawing unit (2).

44. A device according to Claim 43, characterized in that the thread brake (81) is disposed in the area between the last two pairs of rollers (22, 220, 23, 230) of the drawing unit (2).

45. A device according to Claim 44, characterized in that the thread inserter (8) in the insertion position cooperates with the thread brake (81) to form a resilient thread clamp.

46. A device according to Claim 45, characterized in that the thread brake (81) against which the thread inserter (8) of the thread end (12) presses, has a clamping surface made of soft rubber or felt.

47. A device according to one or more of Claims 19 to 46, characterized in that the upper roller (230) of the pair of delivery rollers (23, 230) of the drawing unit (2) is associated with a thread guide (26) which holds the thread end (12) during pulling back to beside the drawing unit (2) until insertion into the drawing unit (2) in the half of the front of the top roller (230) facing the nip line of the pair of delivery rollers (23, 230).

48. A device according to Claim 47, characterized in that the thread guide (26) is in the form of an axial, substantially cylindrical projection (260) of the top roller (230) on the side thereof facing the gripper (7), the diameter (d) of the projection (260) being smaller thant the diameter (D) of the top roller (230).

49. A device according to Claim 47 or 48, characterized in that the top roller (230) has one or more notches (232) in its edge facing the gripper (7) and between its cylindrical surface and front.

50. A device according to one or more of Claims 19 to 49, characterized by a piecing carriage (97) which is movable along a plurality of spinning stations (A, B, C) each having a twisting means (3) and a drawing unit (2) and in which a least one of the elements (94, 93, 95, 47, 60, 7, 8, 81, 5, 261) needed only for the thread-joining process is disposed.

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