EP0311987B1 - Method and device for piecing a yarn in an open-ended spinning machine - Google Patents

Description

The present invention relates to a method for piecing a thread on an open-end spinning device, in which either a thread is returned from a winding device in which it was previously wound onto a spool during the spinning process, or from a special piecing spool to the spinning device, and an apparatus for performing this method.

In the case of open-end spinning machines, thread breakages, such as shell particles, etc. contained in the fiber sliver occur from time to time, which have to be remedied. This is done by returning the end of the torn thread from the bobbin to the spinning device and connecting it to the fibers supplied there on a fiber collecting surface. Another situation arises when the bobbin has to be changed. In such a case, either the spinning as in the case of a thread break occurs with the help of the thread returned by the bobbin before the full bobbin is exchanged for an empty tube, or an auxiliary thread is used for this purpose, which is pulled off by a special piecing bobbin. This pie thread is severed in the course of the piecing process, the thread section which is connected to the newly spun thread and which has the piecing device being separated and removed from the subsequently supplied, newly spun thread and the subsequently supplied thread is transferred to the new sleeve (EP-OS 0.106.809) . In order to achieve controlled piecing, the piecing thread is immediately inserted into the pair of take-off rolls when it is returned and is thus drawn off by it at production speed. The thread thus experiences a very high acceleration during piecing, so that many thread breaks occur at high production speeds or piecing is not possible at all. Since the take-off rollers are located in the vicinity of the fiber collecting surface, the twists imparted to the piecing thread can only be distributed over a short region of the thread, so that the thread is easily overtightened. This is another reason why the known device tends to break threads. Since in an open-end spinning machine today there are usually always many identical spinning devices arranged next to one another, it is also possible to lower the speed only for all adjacent spinning devices together, which has an adverse effect on the yarn produced and the production quantity.

It is therefore an object of the present invention to provide a method and a device with the aid of which a reliable piecing is always possible in a simple manner, both after a yarn break and when changing the bobbin, without impairing spinning devices which are not affected.

This object is achieved in that the thread withdrawn from the special piecing spool is brought back near the winding device during its piecing-back delivery, from where it is returned on a return delivery path to the spinning device, which returns with the return path of the thread withdrawn from the spool coincides, and that the thread drawn from the piecing spool after it has been carried out Initially in the vicinity of the winding device, the effect of a controllable take-off is subjected to and discharged, and the subsequent thread is only subjected to the effect of the normal spinning take-off after the full take-off speed has been reached, and is transferred to an empty tube located in the winding device, the excess thread section being attached is separated. As for the return delivery of both the thread drawn from the bobbin and the piecing thread drawn from the piecing bobbin from the area in the vicinity of the bobbin winder where the thread to be returned normally leaves the bobbin during thread breakage recovery, it is the same route possible to use the device which causes the thread draw-off when the thread break to be removed when the special piecing thread has to be removed again after the attachment has been carried out, so that a simple device is sufficient for this. This device is arranged at the end of this common return path, so that the rotation imparted to the spun thread can be distributed over a large section of thread, as long as the twist propagation is not slowed down in any other way. This piecing take-off is controlled according to the respective spinning conditions and finally brought up to the speed of the normal spinning take-off. Now the thread can be transferred to the machine without impairing the yarn quality. The piecing agent, which represents a point of failure, is removed.

In order to avoid uncontrolled pulling of the piecing thread from the piecing bobbin and thus also to have a controlled guidance of the piecing thread from the beginning of the piecing feed, it is advantageously provided that the piecing thread is braked while it is being drawn off from the piecing bobbin.

Also the aim of achieving a controlled piecing delivery of the piecing thread is the advantageous measure that the piecing thread mechanically moves from a ready position into the common one Return delivery route is promoted. In order to supply the piecing thread, a mechanical feeding device holding the piecing thread is expediently moved to the beginning of the common return path. In order to be able to carry out this movement without additional synchronization with mechanical devices which are arranged in front of this mechanical feed device, it is expediently provided that after the piecing thread has been fed to the mechanical feed device, a thread loop is formed in front of the latter, which loop is then used later during this movement of the feed device is used up at the beginning of the common return route.

According to a preferred embodiment of the method according to the invention, the piecing thread, after having been fed a length sufficient for piecing, is clamped to the common return path between the piecing spool and the mechanical feeding device and cut between this point and the mechanical feeding device, and the free end thus formed extending to the mechanical feeding device Thread section held pneumatically and separated after the spinning and the transfer of the spun thread to the bobbin and discharged pneumatically.

In order to achieve a safe transfer of the spun thread to the bobbin in a simple manner, it is expedient to first pull the spun thread from the spinning device by means of a mechanical feed device and then to transfer it to a pair of take-off rollers for spinning take-off located between the spinning device and the feed device to reduce the thread draw-off speed generated by the mechanical feed device compared to the thread draw-off speed generated by the pair of draw-off rollers and to form the excess thread into a loop and then to cut the thread between the loop and the feed device and to remove the separated thread end while the thread connected to the spinning device is being fed to the bobbin is handed over.

A particularly advantageous piecing method according to the present invention is characterized in that the piecing thread for piecing in connection with a bobbin change is mechanically fed into an air stream which introduces the piecing thread into the open clamping line of a pair of auxiliary rollers, so that the piecing thread is brought to a standstill near its leading end and a thread loop is formed from the still supplied piecing thread, that subsequently the subsequent delivery of the piecing thread is interrupted and the pair of auxiliary rollers is brought into the effective range of a suction air stream using the thread loop while using the thread loop, then the piecing thread by driving the pair of auxiliary rollers and synchronous removal of the piecing thread from the piecing bobbin is returned with its leading end into a standby position within the spinning device, forming a piecing reserve, whereupon the piecing thread in transport seal in front of the pair of auxiliary rollers and the thread end extending to the pair of auxiliary rollers is exposed to a suction air stream, that then the piecing takes place by releasing the fiber feed and the piecing reserve, then the spun thread is drawn off with the aid of the pair of auxiliary rollers from the spinning device with increasing speed and supplied to the suction air stream, thereupon the spun thread between the spinning device and the pair of auxiliary rollers is transferred to a pair of draw-off rollers, which is then formed by retarding the pair of auxiliary rollers between this and the pair of draw-off rollers, a thread loop which is pneumatically held and separated from the thread end extending to the suction air flow mentioned, so that this thread end is discharged, whereupon the newly created thread end is transferred to the empty sleeve which has now been inserted.

It has proven to be expedient to carry out the bobbin change in two stages in connection with a batch change, in a first stage the full bobbin being ejected from the winding device and the empty tube being inserted into the winding device only after this spinning device has been prepared for a new one Lot of piecing is initiated with the aid of the piecing thread drawn from the piecing spool.

In order to ensure that after a thread break following a bobbin change the thread lifting does not fail due to an insufficient thread length on the newly inserted sleeve during the bobbin change, in a further expedient embodiment of the method according to the invention it is provided that in connection with a bobbin change the piecing process for a specific one The period of time after transfer of the spun thread to the empty tube is monitored and, in the event of a thread break occurring during this time period, the spinning device is stopped, so that the windings wound onto the empty tube during the previous piecing process are then unwound from the empty tube and then without performing a repeat A new spinning is carried out with the aid of the piecing thread drawn off from the piecing spool.

In order to be able to determine a piecing error at an early stage, the thread itself is preferably monitored as part of the monitoring of the piecing process, which advantageously takes place in the vicinity of the winding device. It is particularly expedient here if the thread is monitored for axial movement.

To carry out the method it is provided according to the invention that the feed device has a pair of auxiliary rollers, from which one roller of the bobbin lifted from the winding roller can be fed as a drive roller and can be driven with the aid of a controllable drive. When a thread break is eliminated, the roller of the pair of auxiliary rollers which can be fed to the bobbin drives the bobbin both for the duration of the piecing return of the thread from the bobbin and for the piecing take-off, the rotational speed of the rollers of the pair of rollers being selected in accordance with the respective conditions. The same roller also delivers the piecing thread drawn from the piecing reel back to the spinning device and then effects the controlled piecing take-off. In this way, regardless of which thread is supplied to the spinning device for spinning, an optimal adaptation to the fiber material to be spun can always be achieved. Exaggerated piecing and Thread breaks are thus avoided. Even thick and thin spots in the piecing that often lead to thread breaks can be largely avoided in this way.

For reasons of a simple construction and a simple feed movement, the roller of the pair of auxiliary rollers designed as a drive roller for the spool is arranged at the free end of a pivot lever.

In order to be able to pick up the piecing thread on the one hand in a simple and rapid manner by the auxiliary roller pair and, on the other hand, to be able to quickly release the thread held by the auxiliary roller pair on the other hand, it is provided in a further expedient embodiment of the subject matter of the invention that the roller of the auxiliary roller pair not deliverable to the bobbin by the as Drive roller for the bobbin trained roller can be lifted off.

If conical coils are produced, it is necessary for the contact surface of the drive roller to run parallel to the outer surface of the coil. This would presuppose that, depending on the conicity of the coil, the roller of the auxiliary roller pair designed as the drive roller and thus the auxiliary roller pair as a whole would have to assume a different position. In order to avoid this, it can be provided in an advantageous manner that the roller of the auxiliary roller pair, which is designed as a drive roller for the coil, is interchangeable and has a first longitudinal section, which cooperates with the coil and has a shape adapted to the coil, and a second longitudinal section which the other roller of the auxiliary roller pair works together. As a result, the pair of auxiliary rollers can always be oriented in the same direction with respect to the coil, since different coil shapes (cylindrical or different conicity) can be compensated for by replacing the roller of the auxiliary roller pair designed as a drive roller with a roller of a suitable shape.

In order to ensure that the part of the roller of the auxiliary roller pair which is designed as a coil drive roller and which cooperates with the other roller does not come into drive connection with the spool without the pair of auxiliary rollers having to protrude laterally beyond the end of the spool, which leads to an increased space requirement, it can expediently be provided that the first length section has a larger diameter than the second length section and the drive of the pair of auxiliary rolls so it is controllable that when a thread break is eliminated, the peripheral speed of the first length section is as great as the peripheral speed of the second length section when piecing in connection with a bobbin change. When the first length section is conical, the cylindrical second length section preferably adjoins the larger diameter of the first length section. In this way, even with relatively small differences in diameter at the transition point between the two length sections, it is ensured that the coil cannot come to rest on the second length section.

The feed device preferably has a thread retention device. Such a thread retention device ensures that the piecing thread to be transferred to the feed device can be delivered in a controlled manner. This ensures on the one hand a reliable transfer of the piecing thread to the feed device and on the other hand prevents excessive thread consumption. The safe and defined transfer of the piecing thread to the feeding device ensures a high piecing security.

The feed device can in principle be designed in various ways; it preferably has a drivable pair of delivery rollers. In order to avoid separate drives for the delivery roller pair and the auxiliary roller pair, it is advantageously provided that the delivery roller pair and the auxiliary roller pair are assigned a common drive motor, to which the delivery roller pair is connected via a controllable coupling. This coupling enables the piecing thread to be conveyed with the aid of the pair of auxiliary rollers in both the one and in the other direction, without additional piecing thread having to be drawn off or returned to the piecing bobbin by the pair of delivery rollers.

In principle, it is possible to drive the auxiliary rollers slightly faster than the delivery rollers, but it has proven to be advantageous if the driven rollers of the delivery roller pair and the auxiliary roller pair can be driven with the same effective peripheral speed.

If the feeding of the piecing thread to the return delivery device takes place through a movement of the auxiliary roller pair in the direction of the return delivery device or if the auxiliary roller pair returns to its rest position with a clamped piecing thread after the end of a piecing process, then the distance between the feed device or piecing bobbin and the auxiliary roller pair changes. To compensate for this change in distance, the feed device advantageously has a storage device. In this way it can be avoided that such differences have to be compensated for, for example, by a corresponding drive of the delivery roller pair.

The storage device can be designed differently. In a simple and therefore particularly expedient embodiment, the storage device is designed as a suction air opening which can be brought into effect between the pair of delivery rollers and the pair of auxiliary rollers. This can be done, for example, in that the suction air opening can be moved into this working position and later returned to a rest position. The storage device is preferably located between the delivery roller pair and the auxiliary roller pair. When the storage device is designed as a suction air opening, it is advantageously arranged stationary in the vicinity of the auxiliary rollers between the delivery rollers and the auxiliary rollers and can be controlled by a shutdown device.

When the storage device is arranged between the pair of delivery rollers and the pair of auxiliary rollers, a thread separating device is expediently provided in front of the storage device in the direction of transport, which is advantageously located between the pair of delivery rollers and the storage device.

In order to avoid that complicated parts with corresponding drives and guides have to be used for transferring the thread to the auxiliary roller pair, it is provided in an expedient development of the subject matter of the invention that the feed device has a pneumatic thread feeder connected upstream of the auxiliary roller pair. In order to be able to work with this in an air-saving manner, the latter preferably has a thread guide tube which extends from the pair of delivery rollers to the pair of auxiliary rollers. It is advantageous if the suction air opening opens laterally into the end of the thread guide tube facing the pair of auxiliary rollers. The thread separating device is also advantageously arranged in the thread guide tube.

In order to be able to build up a thread reserve in the suction air opening in a simple manner, so that when the auxiliary roller pair with the clamped piecing thread moves toward the return delivery device, no drive synchronization between the delivery roller pair and auxiliary roller pair is required, an advantageous embodiment of the device according to the invention is on the side facing away from the delivery roller pair the controllable thread clamp arranged in the suction air opening in the vicinity of the end of the thread guide tube. If the thread is clamped with the help of the thread clamp, a thread reserve can be built up in the suction air opening if the piecing thread continues to be delivered, which is then used up again after the auxiliary roller pair has taken up its clamping position when the auxiliary roller pair moves to the return device. This thread clamp is expediently arranged in the thread guide tube, and in a simple embodiment of this device the controllable thread clamp can have a movable clamping part made of elastic material.

For simply placing the piecing thread in front of the pair of auxiliary rollers, it is provided according to an advantageous embodiment of the subject matter of the invention that the feed device comprises a compressed air nozzle directed towards the clamping line of the pair of auxiliary rollers, which is located between the pair of delivery rollers and the auxiliary roller pair can be brought into effect. It is expedient if the compressed air nozzle is designed as an injector nozzle, which opens into the end of the thread guide tube facing the pair of delivery rollers.

Since the compressed air nozzle should be effective until the piecing thread comes into the clamping line of the pair of auxiliary rollers and the thread reserve has been built up in the suction air opening, it can be provided that the drive of the roll-off roller of the auxiliary roller pair together with the compressed air nozzle with a common control device in terms of control stands.

In order to be able to guide the piecing thread as far as possible in the direction of the clamping line of the auxiliary roller pair, it is advantageous if the shape of the thread guide tube at its end facing the auxiliary roller pair is adapted to the gusset of this auxiliary roller pair.

In order not only to be able to carry out the usual piecing or the usual bobbin change with the piecing required in this context, a control device with a plurality of control programs is preferably provided, which can be called up depending on whether a thread break immediately following a bobbin change or independently thereof occurs or whether a spool change is to be carried out in connection with a lot change or independently of this.

In the exemplary embodiment described above, the thread retention device also serves as a conveying means for the piecing thread and is therefore formed by a pair of delivery rollers. However, it is not necessary for the functions of thread retention and thread conveyance to be performed by one and the same element. According to a further advantageous embodiment of the device according to the invention, it is provided that the thread retention device is designed as a storage device and the feed device has a thread clamp which can be moved from one side of the auxiliary roller pair in the receiving position to the other side thereof.

So that piecing faults can be recognized early and a failed piecing attempt can be interrupted at an early stage in order to then make a new piecing attempt, it is advantageous if a monitoring device monitoring the spun thread is provided. It has proven to be particularly expedient if the monitoring device is assigned to a thread removal device for removing the thread before it is transferred to the winding device, since additional guide means are then not required. The monitoring device is preferably assigned to the suction air opening through which the piecing device is discharged. In this way, the monitoring device is in relatively close proximity to the winding device, so that it can determine all errors in the yarn path between the spinning device and the winding device. The monitoring security is further increased if, in a further advantageous embodiment of the subject matter of the invention, the monitoring device is designed such that it can distinguish between an axially immobile and an axially movable thread.

In today's open-end spinning machines with a large number of open-end spinning devices arranged next to one another, at least one maintenance device which can be moved along these spinning devices is generally provided. In an advantageous embodiment of the subject matter of the invention, the piecing spool, the feed device, the feed device and the return device are advantageously arranged on this maintenance device in this case. In order to avoid a separate vacuum source for the suction air opening in the case of a movable maintenance device, in this case the suction air opening is preferably connected to a machine-side vacuum source.

The present invention makes it possible in a simple manner to always carry out an optimal piecing process, depending on the special conditions. Even if immediately after a bobbin change Thread breakage occurs, a failure of the following piecing process is avoided by piecing with the help of a special piecing thread. The device according to the invention enables a defined feed of the piecing thread to the spinning device and a defined insertion of the take-off after piecing return delivery, the special arrangement of the auxiliary roller pair and its drive control not only making it possible to adapt to the fiber material being spun, but also to control the thread size enable in the piecing area and in the area adjoining it. This ensures a high level of security. The device according to the present invention is furthermore simple in control and compact in construction, since no elements are arranged in the entire area between the normal bobbin and the spinning device and no elements are brought into this area which are used to feed the piecing thread to the spinning device serve. In addition, the device according to the invention can also be retrofitted to existing piecing devices, since only the existing swivel lever with the auxiliary drive roller for the spool and the control system must be replaced for this purpose, and the feed device must also be installed.

Fig. 1

im schematischen Querschnitt eine Offenend-Spinnvorrichtung sowie eine erfindungsgemäße Anspinnvorrichtung in der normalen Spinnstellung;

Fig. 2 bis 8

im schematischen Querschnitt die in Fig. 1 gezeigte Vorrichtung in verschiedenen Arbeitsphasen bei einem Anspinnen im Zusammenhang mit einem Spulenwechsel;

Fig. 9 und 10

im schematischen Querschnitt die in Fig. 1 gezeigte Vorrichtung in verschiedenen Arbeitsphasen beim Beheben eines Fadenbruches,

Fig. 11

in der Frontansicht das Hilfswalzenpaar in der Spulenantriebsstellung,

Fig. 12

im Längsschnitt das dem Hilfswalzenpaar zugewandte Ende des in den Fig. 1 bis 10 gezeigten Fadenführungsrohres,

Fig. 13 bis 15

im schematischen Querschnitt eine Abwandlung der erfindungsgemäßen Vorrichtung in verschiedenen Arbeitsphasen;

Fig. 16

im Schema die Steuervorrichtung mit verschiedenen Programmen für das Fadenbruchbeheben und den Spulenwechsel.

Embodiments of the invention are explained in more detail below with reference to drawings. Show it:

Fig. 1

in schematic cross section an open-end spinning device and a piecing device according to the invention in the normal spinning position;

2 to 8

in a schematic cross section the device shown in FIG. 1 in different working phases during piecing in connection with a bobbin change;

9 and 10

1 shows a schematic cross section of the device shown in FIG. 1 in various working phases when a thread break is eliminated,

Fig. 11

in the front view the pair of auxiliary rollers in the spool drive position,

Fig. 12

in longitudinal section the end facing the pair of auxiliary rollers of the thread guide tube shown in FIGS. 1 to 10,

13 to 15

a schematic cross section of a modification of the device according to the invention in different working phases;

Fig. 16

in the diagram the control device with various programs for thread break repair and bobbin change.

First, the general structure of an open-end spinning device is described with reference to the left-hand side of FIG. 1, only the devices and elements which are absolutely necessary for understanding the different piecing processes being shown.

In an open-end spinning element, which is designed as a spinning rotor 1 in the exemplary embodiment shown in FIG. 1, a thread 10 is spun which is drawn off through a thread draw-off tube 11 with the aid of a pair of draw-off rollers 12. This pair of draw-off rollers 12 has in the usual way a driven roller 120 and a pressure roller 121 which can be lifted off from it. The thread 10 passes on its way to a winding device 13 a thread tension compensation guide 14 and a traversing thread guide 15 which is used for the crosswise laying of the thread 10 on a in the winding device 13 located coil 132 is moved back and forth. The coil 132 is clamped between two coil arms 131, which can be pivoted about an axis 133. During the spinning operation, the bobbin 132 rests on a driven winding roller 130.

The winding device 13 also has a bobbin lifting device 134 which can be brought between the winding roller 130 and the bobbin 132. For this purpose, the drive device, not shown, of the bobbin lifting device 134 is connected in terms of control to a thread monitor 16, which is arranged in the thread run in the vicinity of the outlet mouth of the thread take-off tube 11. The spool lifting device 134 is also assigned a drive device (not shown) of the piecing device, so that the spool lifting device 134 can be returned from its lifting position shown in FIG. 2 to its basic position shown in FIG. 1.

Between the spool arms 131 there is a spool ramp 17, over which the full spools 132 can be fed to a conveyor belt, not shown, in order to be able to feed the spools 132 to a collection point.

An empty tube feed device 19 is provided above the winding device 13, from which the empty tubes 190 required for this (see FIG. 2) are removed when the bobbin is changed.

A part of a piecing device is shown on the right in FIG. 1, which is arranged on a maintenance device 2. This maintenance device 2 can be moved along a large number of spinning stations arranged side by side, each of which has a spinning device, a thread monitor 16, a pair of take-off rollers 12, a thread tension compensation guide 14, a traversing thread guide 15, a winding device 13 and a bobbin ramp 17.

The piecing device arranged on the maintenance device 2 has a return delivery device 20 which, among other things, has a suction nozzle 200, a centering spindle 21 (FIG. 5) and a discharge spindle 25. The suction nozzle 200 has the task of sucking the end of the broken thread 10 from the spool 132 in the event of a thread break. For this purpose, the bobbin 132 is turned back by means of an auxiliary drive roller 24. In a known manner, the suction nozzle 200 has a slot on its side facing the spinning device, from which the thread 10 sucked back finally emerges and is fed to a feed device, not shown, which in turn conveys the thread 10 to the mouth of the thread take-off tube 11.

The described return delivery device 20 is not only used for removing the broken thread, but also in connection with piecing when changing the bobbin. This piecing takes place with the aid of a piecing thread 30 which is drawn off from a piecing bobbin 3. The piecing thread 30 is fed with the aid of a feed device 4 to a feed device 5, from which the piecing thread 30 reaches the return delivery device 20.

The feed device 4 has a pair of delivery rollers 40, of which at least the delivery roller 400 can be driven. The other delivery roller 401 generally does not need its own drive, but if desired, a direct drive can also be provided for this delivery roller 401. The delivery roller 400 is driven by a drive wheel 402, which in turn by means of a clutch, not shown, with the aid of a Timing belt 403 or the like is driven by a drive motor 404. This drive motor 404 in turn drives the feed device 5 via a toothed belt 50 or the like, which has an auxiliary roller pair 52 as the most important component. The auxiliary drive roller 24 is part of an auxiliary roller pair 52 and is driven in a manner not shown via a drive wheel 51, which in turn receives its drive via the toothed belt 50 mentioned. In addition to the auxiliary drive roller 24, the auxiliary roller pair 52 also has a pressure roller 520 which can be brought into contact with the auxiliary drive roller 24 by means of a magnetic drive 53 or can be lifted off the latter again. The pair of auxiliary rollers 52 is located at the free end of a pivot lever 54 which also carries the magnetic drive 53 and is pivotably mounted on the axis 540 of the drive wheel 51.

Between the auxiliary roller pair 52 shown in its thread take-up position and the delivery roller pair 40, there is a thread guide tube 41 which bridges the distance between these roller pairs 52 and 40. The thread guide tube 41 has, at its end facing the pair of delivery rollers 40, a conical widening 410 which widens in the direction of the pair of delivery rollers 40, which makes it easier to thread the piecing thread 30 into the thread guide tube 41. Shortly after the conical extension 410, an injector nozzle 411 opens laterally into the thread guide tube 41. This injector nozzle 411 is assigned a valve 412, with the aid of which the compressed air supply into the thread guide tube 41 can be controlled.

A thread separating device 413 is arranged in the vicinity of the entry into the thread guide tube 41.

In the vicinity of the exit-side end of the thread guide tube 41, a thread clamp 42 is provided, which consists of a stationary part 420 and a part 421 that can be lifted off. In the vicinity of this thread clamp 42 on the end facing the pair of auxiliary rollers 52 opens laterally into the thread guide tube 41 a suction opening 43. This suction opening 43 forms a store and is connected via a valve 430 to a suction line 431 which, in the working position of the maintenance device 2, is connected to a central vacuum source (not shown) via a suction line 18 of the open-end spinning machine.

With the help of the aforementioned centering spindle 21, the thread 10 or the piecing thread 30 can be brought into such a position that it can be picked up by a suction tube 22 which can be advanced to the thread path (FIG. 8) and which is connected to the suction line 18 in a manner not shown . On the side facing the pair of auxiliary rollers 52, the suction tube 22 has a separating device 221 in the vicinity of its mouth 220. Furthermore, the maintenance device 2 has a guide fork 23, with the aid of which the spun thread for the transfer to the empty tube 190 inserted in the winding device 13 into a cheap one Position can be brought.

Now that the open-end spinning device and the piecing device have been described in structure, the function of these devices in connection with a spool change is explained below:

First of all, the spinning station is in a state as shown on the left in FIG. 1. If the coil 132 has reached the desired target size, this is registered in a known manner. For this purpose, for example, the revolutions of the rollers 120 of the pair of draw-off rollers can be counted from the insertion of the empty tube, which are compared with a predetermined target value. The passing maintenance device 2 can also scan the coil. When the desired target size is reached, the maintenance device 2 is stopped before this spinning station. A thread break is now produced in a known manner by preventing the supply of fibers into the spinning rotor 1.

With this intentional thread break, the thread monitor 16 is actuated, which now causes the spring-loaded bobbin lifting device 134 to be released. This bobbin lifting device 134 now accelerates from the rest position shown in FIG. 1 into its working position between the winding roller 130 and the bobbin 132, so that the bobbin 132 is separated from its drive.

At this point, the piecing thread 30 is in a waiting position, in which it is clamped by the pair of delivery rollers 40 and extends into the thread guide tube 41. After the maintenance device 2 has registered that the full spool 132 is to be exchanged for an empty tube 190, the program for the spool change is started.

First of all, the piecing motor 404 and the clutch (not shown) assigned to the delivery roller pair 40 are switched on, so that both the delivery roller pair 40 and the auxiliary drive roller 24 of the auxiliary roller pair 52 are now put into operation via the toothed belts 403 and 50. At the same time, the valve 412 is opened so that compressed air is blown into the thread guide tube 41 via the injector nozzle 411. In this way, a suction air flow is generated in the entry area (extension 10) of the thread guide tube 41, which detects the piecing thread 30, even if it should have previously slipped out of the thread guide tube 41. While the piecing thread 30 is mechanically conveyed into this air flow by the pair of delivery rollers 40, this flow ensures that the piecing thread 30 reaches the thread clamp 42. At this time, the pressure roller 520 is lifted off the auxiliary drive roller 24 of the auxiliary roller pair 52, so that the piecing thread 30 is blown through the auxiliary roller pair 52 up to its side facing away from the thread guide tube 41. Now the thread clamp 42 is closed and thus the piecing thread 30 is stopped at its leading end. At the same time, a negative pressure is generated in valve 43 by opening valve 430. This state is shown in Fig. 2.

The full spool 132 is ejected from the spool arms 131 by conventional means and therefore not shown and is fed via the spool ramp 17 to the conveyor belt (not shown) (FIG. 3). During the ejection of the full bobbin 132, the bobbin arms 131 reach their upper position, as shown in FIG. 4. In addition, an empty tube 190 is removed from the empty tube feed device 19 in a manner known per se and inserted into the coil arms 131.

As FIG. 3 also shows, the piecing thread 30, which is still supplied by the pair of delivery rollers 40, forms a reserve loop 31 in the suction opening 43. After a certain time, which is sufficient for the reserve loop 31 to be large enough to prevent the movement of the delivery roller pair 52 from To compensate for the position shown in FIG. 3 into the transfer position according to FIG. 4, the pair of delivery rollers 40 is stopped by actuating the coupling assigned to the drive wheel 402, so that no more thread is supplied. At the same time, the valve 412 is closed, so that the further supply of compressed air into the thread guide tube 41 is prevented. In addition, the magnetic drive 53 is actuated, so that the pressure roller 520 comes to rest on the auxiliary drive roller 24 and the leading thread end jams.

When the delivery roller pair 40 is stopped, the thread clamp 42 is now opened by lifting the part 421 off the stationary part 420. Thereupon, with the feed roller pair 40 still shut down, the pivot lever 54 with the closed auxiliary roller pair 52 is pivoted away from the thread guide tube 41 up to near the winding roller 130 (FIG. 4). With this return delivery, the piecing thread 30 drawn off from the piecing bobbin 3 thus comes close to the winding device 13, the previously formed thread reserve (reserve loop 31) being used up. In this position of the pivot lever 54, the auxiliary drive roller 24 assumes substantially the same position as in thread break repair when it drives the bobbin 132 for returning the end of a broken thread 10 (described in detail later). In this position the auxiliary roller pair 52 is thus in the vicinity of the mouth of the suction nozzle 200, which has meanwhile been brought into the thread take-up position shown. This thread take-up position of the suction nozzle 200 is the same when changing the bobbin and also when removing the thread break, as will be described in more detail later.

Now the clutch assigned to the drive wheel 402 is switched on again, so that in addition to the pair of auxiliary rollers 52, the pair of delivery rollers 40 is now driven again. The drive connections and the diameter of the rollers of the delivery roller pair 40 and the auxiliary roller pair 52 are coordinated with one another in such a way that the roller pairs 52 and 40 are driven at the same peripheral speed. If necessary, the peripheral speed of the auxiliary roller pair 52 can be somewhat be greater than the circumferential speed of the pair of delivery rollers 40, so that the piecing thread 30 between these two pairs of rollers 40 and 52 is subject to a slight delay.

The piecing thread 30 drawn off from the piecing coil 3 and delivered by the pair of auxiliary rollers 52 now comes into the effective range of the suction air flow acting in the suction nozzle 200 and is sucked into the latter. After a sufficiently large thread length has been sucked into the suction nozzle 200 by simultaneously driving the delivery roller pair 40 and the auxiliary roller pair 52 and by the negative pressure effect, the suction nozzle 200 is pivoted back from its thread take-up position shown in FIG. 4 into the rest position shown in FIG. 5 . The piecing thread 30 emerges from the slot (not shown) facing the winding roller 130, which slot can now be opened for this purpose while it was closed when the thread was sucked in. The piecing thread 30 in this case takes up the thread path 30a and thereby arrives at the centering spindle 21, which has meanwhile been brought into the working position shown. The piecing thread 30 takes an elongated course between the centering spindle 21 and the end of the slot facing the pivot point of the suction nozzle 200.

Now, the piecing thread 30 is picked up in a known manner by a pair of rollers (not shown), brought to a certain length by a separating device assigned to this pair of rollers, and then brought with this pair of rollers in front of the outlet mouth of the thread take-off tube 11, the piecing thread 30 reaching the discharge spindle 25, which has now assumed the working position shown, so that a piecing reserve is formed on the ejector spindle 25. By returning the piecing thread 30 together with the aid of the delivery roller pair 40 and the auxiliary roller pair 52, the piecing thread 30 is brought into a standby position within the thread take-off tube 11 of the spinning device (see thread path 30b), in which the thread end has not yet reached the fiber collecting surface of the spinning element (that is designed as a spinning rotor 1) is sufficient.

Even while the piecing thread 30 is in this ready position for the actual piecing, the thread separating device 413 is in front of the auxiliary roller pair 52, i.e. between delivery roller pair 40 and auxiliary roller pair 52, actuated and the piecing thread 30 is cut in the thread guide tube 41. Since the piecing thread in front of the store, i.e. of the suction opening 43, has been severed, the thread end 32 extending to the pair of auxiliary rollers 52 is now sucked in by the suction air flow acting in the suction opening 43. The other thread end 33, which extends to the pair of delivery rollers 40 and is clamped by this, is kept stretched by the air flow which is generated by the vacuum effect in the suction opening 43. The compressed air supply to the injector nozzle 411 can thus be switched off now at the latest if this has not already taken place after the pressure roller 520 has come into contact with the auxiliary drive roller 24 (see FIG. 3). Since the injector nozzle 411 only has to be effective when the pressure roller 520 is lifted off the auxiliary drive roller 24, the magnetic drive 53 for the pressure roller 520 and the injector nozzle 411 can also be controlled synchronously by a common control device.

Usually, during the time during which a spinning device is being prepared for the piecing process, the spinning element, which is designed for example as a spinning rotor 1, is also cleaned. Then the spinning rotor 1 which was previously stopped, for example in the course of cleaning, is released again. During the run-up of the spinning rotor 1, possibly also when a piecing speed has been reached, which may possibly also differ from the production rotor speed, the actual piecing now takes place by throwing off the thread reserve formed by the piecing thread 30 from the ejection spindle 25. The piecing thread 30 now comes out the standby position shown in Fig. 5 except for the collecting surface of the spinning rotor 1 (Fig. 6). The fiber feed is also released in a time-coordinated manner, so that the thread end returned to the spinning rotor 1 now connects to the fibers accumulated in the spinning rotor 1.

When the piecing thread 30 is ejected by the ejection spindle 25, the piecing thread 30 passes between the roller 120 and the pressure roller 121 of the pair of take-off rollers 12 lifted off from it.

The drive motor 404 is switched on again in a timed manner with the ejection of the piecing thread from the ejection spindle 25, but in the opposite direction as before. At the same time, the clutch associated with the drive wheel 402 is actuated so that the pair of delivery rollers 40 is not driven by the drive motor 404. The pair of auxiliary rollers 52 now rotates in the take-off direction and pulls the thread out of the spinning rotor 1 and feeds it to the suction opening 43 (see FIG. 6). The piecing device 34 also enters the suction opening 43.

The drive motor 404 is controllable in its speed and is gradually accelerated during this piecing process according to a predetermined program, until the thread is finally drawn off at a speed which is the same as the peripheral speed of the driven roller 120 of the pair of take-off rollers. Now the pressure roller 121 is brought into contact with the driven roller 120 of the pair of draw-off rollers 12, so that the thread is transferred to the pair of draw-off rollers 12 and is now drawn off from the spinning rotor 1 by the latter.

In this way, the spun thread is first drawn off from the spinning device by the mechanical feed device 5 (pair of auxiliary rollers 52) located in the vicinity of the winding device 13 and only transferred later to the pair of draw-off rollers 12 between the spinning device and feed device 5. The rotation that is given to the thread during the spinning by the spinning rotor 1 can thus be distributed over a large length range of the thread, unless this is prevented by other twist-stop edges etc. For this reason, less rotation gets into the spinning rotor 1 and on its fiber collecting surface, so that more time is available for the period between contact between the thread end and the fiber collecting surface without the risk of the thread being overwound during the spinning and thereby breaking.

During the time during which the newly spun-on thread is drawn out of the spinning rotor 1 by the auxiliary roller pair 52, the mouth 220 of the suction tube 22 is fed to the thread between the auxiliary roller pair 52 and the centering spindle 21.

After a time which is so long as to ensure that the piecing unit 34 has passed the auxiliary roller pair 52, the auxiliary roller pair 52 is stopped by means of the drive motor 404 or at least slowed down in relation to the extraction roller pair 12, so that between the extraction roller pair 12 and the auxiliary roller pair 52 a thread excess arises which is sucked into the suction tube 22 as a thread loop 100. When this thread loop 100 has reached a sufficient size so that the newly spun thread 10 supplied by the draw-off roller pair 12 can be securely held pneumatically by the suction tube 22, the separating device 221 is actuated. The mouth 220 of the suction tube is designed in such a way - or corresponding guides are assigned to it that the part of the thread loop 100 fed to the auxiliary roller pair 52 is located in the area of the separating device 221, while the part of this thread loop 100 facing the pulling-roller pair 12 is not in the area of this separating device reached. This ensures that the thread 10 is severed between the thread loop 100 and the feed device 5 and is held securely by the suction tube 22 even after the thread loop 100 has been cut through. The separated thread end is pulled out of the suction tube 22 by the pair of auxiliary rollers 52. After leaving the auxiliary roller pair 52, this separated thread end is removed through the suction opening 43 (see FIG. 7).

Now the bobbin arms 131 are lowered with the empty tube 190 inserted, so that the empty tube is driven again by the winding roller 130.

The thread 10 continuously supplied by the take-off roller pair 12 continues to enter the suction tube 22. The auxiliary roller pair 52, which is now no longer required, is moved back into its starting position shown in FIG. 1. The magnetic drive 53 releases the pressure roller 520 so that it can return to its basic position.

The centering spindle 21 is now driven so that it sheds the thread 10 and passes it into a guide fork 23 previously brought to the centering spindle 21 (FIG. 8). At the same time, the suction pipe 22 is brought into the transfer position in which the thread 10 entering the suction pipe 22 reaches the area of a catch device (not shown) on one of the sleeve plates 135 at the end of one of the bobbin arms 131. As a result, the thread is transferred to the empty tube 190. The yarn 10 subsequently supplied by the take-off roller pair 12 is thus wound onto the empty tube 190, with appropriate control of the guide fork 23 ensuring that a plurality of reserve windings are first formed before the thread 10 is released by the guide fork 23 and thereby in the stroke area of the traversing thread guide 15 arrives, whereupon regular turns are formed on the empty sleeve 190.

In coordination with the transfer of the thread 10 to the catching device on the sleeve plate 135 and thus to the empty tube 190, the separating device 221 in the suction tube 22 is actuated again, whereby the excess thread end is separated from the thread 10 transferred to the empty tube 190 and then through the suction tube 22 is discharged.

The bobbin changing process and the piecing process to be carried out in connection with this bobbin changing process are thus ended. The elements of the spinning station now assume their spinning position again, as shown in FIG. 1.

All elements of the piecing device are returned to their basic position. The maintenance device 2, which is no longer required at this spinning station, now continues to the next spinning station at which maintenance is to be carried out.

The device described above for carrying out a bobbin change and a piecing to be carried out in this connection is designed so that it does not engage in the working area of the return device 20, so that it can be designed in a conventional manner and thus also works in the usual way. The auxiliary drive roller 24 is arranged at the interface between the feed device 5 and the return device 20, which is why the auxiliary drive roller 24 is simultaneously formed as a component of the auxiliary roller pair 52. Thus, when removing a normal thread break, i.e. regardless of a bobbin change, the pivot lever 54 with the auxiliary drive roller 24 of the auxiliary roller pair 52 also required; however, when the thread break is eliminated, the auxiliary drive roller 24 fulfills the task of driving the full bobbin 132. For this reason, this auxiliary drive roller 24 is delivered as a drive when the yarn break is removed from the bobbin 132 lifted off the winding roller 130.

Such a thread break repair without simultaneous bobbin change will now be explained in more detail.

In the starting position shown in FIG. 1, the thread 10 is continuously wound onto the bobbin 132. If a thread break occurs, a control pulse is emitted by the thread monitor 16, which causes the supply of fibers in the spinning rotor 1 to be stopped. In addition, a control pulse is given to the drive of the coil lifting device 134, which releases it and brings it into the position shown in FIG. 2.

The maintenance device 2 now comes to the relevant spinning station. This can take place on the basis of a call signal which has been emitted by the thread monitor 16; but this can also be done in that the maintenance device 2 travels along the machine and carries out necessary maintenance work at all those spinning positions which it passes anyway.

If the maintenance device 2 has reached such a spinning position at which a thread breakage has occurred, the maintenance device 2 stops. The spool arms 131 are raised by a lifting device (not shown) to such an extent that the spool 132 is lifted off the spool lifting device 134, so that the spool 132 is freely rotatable. In order later to be able to achieve a thread length lying within predetermined tolerances for piecing, this lifting device, not shown, is designed such that the distance between the bobbin 132 and the bobbin roller 130 is always the same.

Now the pivot lever 54 is pivoted in the direction of the coil until the auxiliary drive roller 24 comes to rest against the coil 132 (FIG. 9). The drive motor 404 is driven so that the bobbin 132 is rotated in the opposite direction to the normal winding direction, so that the suction nozzle 200, which has now been brought into its thread take-up position, can receive the end of the broken thread 10 from the bobbin 132. The other piecing operations correspond to those previously described with reference to FIGS. 5 and 6 (see FIG. 10). Since the thread 10 is already connected to the bobbin 132, the operations for transferring the newly spun thread to the bobbin 132 are unnecessary (compare FIGS. 7 and 8).

As a comparison of FIG. 4 with FIG. 10 shows, the thread is between the winding device 13 and the spinning device (thread take-off tube) both when it is returned from the bobbin 132 and when it is drawn off from the piecing bobbin 3 11) returned on a return delivery route to the spinning device, which is the same in both cases.

When the bobbin 132 driven by the auxiliary drive roller 24 has reached its normal winding speed, which it has during production, the bobbin 132 is brought back into contact with the winding roller 130 from the maintenance device 2, while the pivoting lever 54 with the auxiliary drive roller 101 is pivoted back into its basic position shown in FIG. 1.

As a comparison of FIG. 9 with FIG. 4 shows, the suction nozzle 200 is in the same position both when piecing in connection with a bobbin change and when the thread is broken. In both cases, the return of the thread 10 or the piecing thread 30 to the spinning device takes place by means of the drive of the auxiliary drive roller 24. The further operations through which the thread is delivered into the thread take-off tube 11 and into the spinning rotor 1 are identical with the only difference that in connection with a bobbin change the piecing thread 30 and later the newly spun thread with the help of the auxiliary take-off roller pair 52 and thus with the help of the auxiliary drive roller 24 directly and when removing the thread break with the aid of the auxiliary drive roller 24 indirectly via the bobbin 132 in the return or the withdrawal direction is promoted (see also Fig. 10).

The above description makes it clear that the thread 10 or the piecing thread 30 from the area in which the auxiliary drive roller 24 is in its transfer or bobbin drive position is always conveyed back into the spinning rotor 1 in one and the same way. The draw-off of the spun thread also takes place in both cases at the beginning of this common thread return path, namely in the vicinity of the winding device 13, in a controlled manner, the take-off speed being controlled in both cases with the aid of the auxiliary drive roller 24, which is also part of the auxiliary roller pair 52 .

In order not to confuse the representation of the devices described, the figures do not show the tax-related connections. Conventional means can be used to control the individual elements.

With reference to Fig. 16, the control of various methods of thread break repair or bobbin changing will be explained below. Four programs 60, 61, 62 and 63 are stored in the control device 6 shown there.

The program 60 includes the normal thread break repair, as was described with the aid of FIGS. 9 and 10. As shown in FIG. 16, this program is initiated by responding to the thread monitor 16.

The bobbin changing program with subsequent piecing, as has been described with the aid of FIGS. 1 to 8, is contained in program 62. This program 62 is triggered by triggering a switch 64. This switch 64 is formed by a light barrier which scans the diameter of the bobbin 132 or else by a counting device which scans the number of revolutions of the roller 120 of the draw-off roller pair 12 and thereby determines the thread length since the last bobbin change. Other devices can also be provided, with the aid of which it can be determined whether the coil 132 has reached its desired size.

With the control line 640 between the switch 64 and the program 62, the drive 642 of a switching device 643 is connected via a connecting line 641, with which the thread monitor 16 can optionally be connected to the program 60 or to the program 61. This program 61 is used to correct thread breaks immediately following a bobbin change that has just been carried out. In such a case, there is generally no length of thread on the newly inserted empty tube 190 such that re-spinning is possible.

In particular in connection with a bobbin change, the piecing process is still monitored by the maintenance device 2 for a certain time. This can be done with the help of the thread monitor 16 mentioned or a traverse monitoring device which determines whether the spun on Thread is present or after a predetermined time after spinning a traversing movement - as a result of the insertion in the traversing thread guide 15 - executes or not. If this is not the case, the program 61 is triggered. Here, the spinning device is first stopped again (interruption of the fiber feed, lifting of the empty tube 190). The empty sleeve 190 is then emptied. This can be done, for example, by hand or by moving the suction nozzle 200 to the raised and freely rotatable empty sleeve 190. Now the pivot lever 54 with the auxiliary drive roller 24 is brought into contact with the empty sleeve 190, so that when the empty sleeve 190 is turned back at the same time, the few turns located thereon can be unwound and suctioned off by the suction nozzle 200. Then a piecing process takes place with the aid of the piecing thread 30, as was previously described with the aid of FIGS. 2 to 8, but without a new bobbin change being carried out. This program 61 can also be set so that it can still be carried out if the maintenance device 2 has already left the spinning station when a thread break occurs following a bobbin change and the fault is only remedied the next time it passes the spinning station .

As shown in FIG. 16 by the control connection 644 shown in dashed lines, the control line 640 can also be connected to the thread monitor 16 via the changeover device 643. In this case, the program 61 is omitted, so that in the event of a thread break occurring after a bobbin change, a new bobbin change is carried out, the empty tube 190 being removed with the few turns on it.

In order to be able to determine at an early stage whether a piecing attempt fails, both the suction pipe 22 and the suction line 431 are equipped with a monitoring device 222 or 432 according to FIGS. 1 to 10, which serves to monitor the spun thread.

These monitoring devices 222 and 432 are activated as part of the piecing monitoring at the times when a thread enters the suction pipe 22 (see work phase according to FIG. 8) or into the suction line 431 (see work phases according to FIGS. 3, 6 and 7) Must extend, both of which form a thread removal device and remove the thread before it is transferred to the winding device 13. If the thread is found to be missing, the piecing process is interrupted and a new piecing process is initiated. Such monitoring devices 222 and 432 can also detect winding formations on the pair of draw-off rollers 12, since in such a case the thread monitor 16 detects the presence of the normal draw-off tension, the monitoring device 222 and / or the monitoring device (432) registers the absence of the thread.

The monitoring device can be designed in a manner known per se, e.g. as a light barrier. However, it is advantageous if the monitoring device can distinguish between a standing (axially immobile) and a running (axially movable) thread, i.e. is designed as a thread running monitoring device. If the thread is monitored for axial movement, errors that occur after the thread has started to be removed with the aid of the suction pipe 22 or the suction line 431, e.g. a sticking of the thread, registered.

If necessary, a single monitoring device 222 or 432 is also sufficient, in which case it is then expedient to place this single monitoring device in the vicinity of the end of the thread path, i.e. to be arranged in the vicinity of the winding device 13. The closer the monitoring device 432 is to the end of the thread path (e.g. in the suction air opening 43 or the suction line 431), the more errors can be monitored by this monitoring device.

It has proven to be expedient not to carry out a normal spool change when a lot change is to be carried out, as previously described with the aid of FIGS. 1 to 8. In order to ensure that fiber residues from the old batch cannot get into the new yarn during the spinning process after the batch change, it is rather advantageous to clean the spinning machine and thus the individual spinning stations beforehand. For this reason, the spool change in connection with a lot change is carried out in two stages according to the method described below. First, by actuating a switch 65, the first phase 630 of the program 63 is initiated, in which a thread break is generated in each case by stopping the fiber feeding devices and then the full bobbins 132 are ejected from the winding devices 13 of the various spinning positions. The spinning machine is then stopped and the individual spinning devices are prepared for the new batch, which includes cleaning the machine or readjusting the piecing device in the maintenance device 2. If this has happened, the second phase 631 of the program 63 is initiated by actuating the switch 650. In this phase 631, the empty tubes 190 are then inserted into the winding devices 13 and piecing is carried out with the aid of the piecing thread 30, as was described above.

As indicated in FIG. 16 with the aid of the control connection 651, the phase 631 of the program 63 can be identical to the program 62. In this case, a program is carried out in this second phase 631, as was described with the aid of FIGS. 1 to 8. However, the full bobbins 132 are no longer ejected because the bobbins 132 were already ejected in the previous phase 630.

As described above, the various programs 60, 61, 62 and 63 can thus be called up depending on whether a thread break occurs in connection with a bobbin change or independently of it or whether a bobbin change is carried out in connection with a lot change or independently of this.

It goes without saying that locking devices, such as diodes, which are not shown, prevent the individual programs 61, 62 and 63 from being mixed together in an undesired manner. 16 is not shown for the sake of clarity.

The device described can be modified in a variety of ways by replacing elements with equivalents or by other combinations.

An advantageous embodiment of the thread guide tube 41 and of the thread clamp 42 is shown in FIG. So that the piecing thread 30 is guided in the immediate vicinity of the pair of auxiliary rollers 52 in order to enable the thread to be inserted securely into this pair of auxiliary take-off rollers 52, the end of the thread guide tube 41 facing the pair of auxiliary rollers 52 is adapted to the gusset shape of the pair of auxiliary rollers 52.

In principle, the thread clamp 42 can also be arranged in the vicinity of the thread guide tube 41 between the latter and the auxiliary roller pair 52, but an arrangement in this thread guide tube 41 is particularly favorable for good thread guidance. 12, the part 420 of the thread clamp 42 is formed by the inner wall of the thread guide tube 41, while the movable part 421 of the thread clamp 42 is formed by an element made of elastic material, which is formed by a pivot lever 422 is held. This pivot lever 422 is mounted on the thread guide tube 41 and connected in terms of control to an electromagnet 423, with the aid of which the elastic part 421 can be brought into or out of the working position.

The device described is suitable both in connection with the production of cylindrical and the production of conical coils. In the latter case, it is necessary that the surface line of the Auxiliary drive roller 24 runs parallel to the surface line of the coil 132. This can be achieved in that the auxiliary roller pair 52 is pivotally and adjustably attached to the pivot lever 54.

Another configuration of the auxiliary roller pair 52 is shown in FIG. 11. In this embodiment, the auxiliary drive roller 24 has two longitudinal sections 240 and 241. The first longitudinal section 240 has a larger diameter than the second longitudinal section 241 and is also adapted to the taper of the spool 132. If the coil 132 is thus cylindrical, the length section 240 also has a cylindrical shape. If, on the other hand, the bobbin 132 is conical, the longitudinal section also has a taper in such a way that the axes 136 and 242 of the bobbin 132 or auxiliary drive roller 24 run parallel. While the length section 240 works together with the spool 132, the length section 241 with the smaller diameter is provided for cooperation with the pressure roller 520.

If a change is made from the production of a specific coil shape to another, it is sufficient to replace the auxiliary drive roller 24 with another auxiliary drive roller 24, the length section 240 of which is designed in accordance with the coil shape to be produced.

Since the auxiliary drive roller 24 serves to control the piecing take-off both when removing the thread break and when changing the bobbin, the piecing take-off being carried out via the bobbin 132 and the auxiliary bobbin 24, the diameters of the two length sections 240 and 241 and the speeds, with which the auxiliary drive roller 24 is fixed when the thread breaks or when the bobbin is changed by the drive motor 404, is coordinated with one another in such a way that the thread is always drawn off from the spinning station at the same take-off speed. This is the case if the (average) circumferential speed of the first length section 240 is as great as the circumferential speed of the second length section 241 during piecing when a thread break is eliminated in connection with a bobbin change. If a coil 132 of a different shape (cylindrical or conical or also a different conicity) is to be produced, an exchange of the auxiliary drive roller 24 is sufficient for adaptation. A different angular position of the auxiliary roller pair 52 or an exchange of the pressure roller 520 is not necessary.

If the first length section 240 is conical, in principle the second length section 241 can optionally connect to the smaller or the larger diameter. If it is provided that the second length section 241 connects to the large diameter of the first length section 240 of the auxiliary drive roller 24, the risk that this second length section 241 comes to rest against the circumference of the coil 132 is small, even with a small diameter jump, so that Undetermined drive conditions can be avoided even with small jumps in diameter.

In principle, it does not matter whether the auxiliary drive roller 24 or the pressure roller 520 cooperating with it is arranged closer to the pivot axis 540. However, arranging the auxiliary drive roller 24 in the vicinity of the free end of the pivot lever 54 offers greater design freedom. It is also not absolutely necessary to design the pressure roller 520 so that it can be lifted off the auxiliary drive roller 24, since by appropriately driving the auxiliary roller pair 52, the piecing thread 30 can both run in its clamping line and also come out of it. If necessary, an additional clutch can be provided for the pair of auxiliary rollers 52.

In order not to have to search the piecing thread 30 again for each piecing process that is to be carried out with its help, for example with the aid of a suction nozzle, which is similar to the suction nozzle 200, the piecing thread 30 is guided through a thread retention device. In the exemplary embodiment described above, this thread retention device is formed by the pair of delivery rollers 40. This pair of delivery rollers 40 also enables a controlled thread feed to the feed device 5.

A stationary auxiliary roller pair 52 to which the piecing thread 30 is fed by other mechanical or pneumatic means is indeed conceivable for feeding the piecing thread 30 into the common return path mentioned. However, it is particularly simple - as shown - to provide a swivel lever 54 or another movable element for the auxiliary roller pair 52 which is moved from a thread take-up position (FIG. 1) to a thread transfer position (FIG. 4). In order to avoid a synchronization between the run of the delivery roller pair 40 and the run of the auxiliary roller pair 52 and the pivoting lever movement, a reserve loop 31 is formed in front of the mechanical feed device 5 according to the described embodiment, which is used up again with such a feed movement of the feed device 5.

According to the embodiment described, the feed device 4 has a pneumatic thread feeder upstream of the auxiliary roller pair 52 in the form of a thread guide tube 41 which extends from the supply roller pair 40 to the auxiliary roller pair 52. Alternatively, however, a pneumatic thread feeder in the form of a swiveling suction tube or a compressed air nozzle is also possible, which can be brought into effect between the pair of delivery rollers 40 and the pair of auxiliary rollers 52 and which is directed onto the clamping line of the pair of auxiliary rollers 52 in order to feed the piecing thread 30 to this pair of auxiliary rollers 52.

If a storage device is connected upstream of the feed device 5 to compensate for the thread feed movement (between the delivery roller pair 40 and the auxiliary roller pair 52), this can also be designed mechanically in the manner of a storage device which is conventional per se. If such a storage device is designed pneumatically, it can be arranged in a stationary manner between the supply roller pair 40 and the auxiliary roller pair 52 or can be brought temporarily into this area for its work. To save air, this can be switched on and off by a switch-off device (valve 430).

The vacuum source for such a piecing device can be arranged on the maintenance device 2 itself; however, the suction opening 43 of the pneumatic accumulator can, as shown in FIGS. 1 to 10, be connected via the suction line 18 to a machine-side vacuum source (not shown).

Another embodiment of a feed device 4 is described below with reference to FIGS. 13 to 15, with the aid of which the piecing thread 30 is brought mechanically into the auxiliary roller pair 52 and from there mechanically into the previously mentioned common thread return path. While in the exemplary embodiment described above, the retaining device is formed by a pair of delivery rollers 40, a mechanical storage device 44 is provided for this in FIGS. 13 to 15, in which the thread 30 drawn off from the piecing bobbin 3 is guided in a zigzag. This storage device 44 has two comb-like elements 440 and 441 which are under spring tension and tend to move away from one another and thereby build up a thread reserve.

On the side of the storage device 44 facing away from the piecing spool 3 there is a pivoting lever 45 which can be pivoted about an axis 450 and has an openable and closable thread clamp 451 at its end.

The pivot lever 54 with the auxiliary roller pair 52 and the pivot lever 45 with the thread clamp 451 are mounted in such a way that the thread clamp 451 can be brought either to one or the other side of the auxiliary roller pair 52 brought into the thread take-up position. This can be seen from a comparison of FIGS. 13 and 14.

In the starting position, the pivot lever 54 and the pivot lever 45 assume the positions shown in FIG. 13. The thread clamp 451 holds the start of the piecing thread 30, while the auxiliary roller pair 52 is in the thread take-up position before the beginning of the piecing thread 30.

By a suitable movement of the pivoting lever 45, the thread clamp 451 is brought to the side of the auxiliary roller pair 52 facing away from the storage device 44, whereupon the pressure roller 520 is brought into contact with the auxiliary drive roller 24 and the thread clamp 451 is opened (see FIG. 14).

During the pivoting movement of the pivot lever 45, the piecing thread is braked by the storage device 44, so that the piecing thread 30 is not pulled off the piecing coil 3 in an uncontrolled manner. The thread reserve stored in the storage device 44 is reduced until after the swiveling movement of the pivoting lever 45 the thread reserve reaches its full size again by pulling off the piecing thread from the piecing spool 3 again.

After the piecing thread 30 has been taken over by the auxiliary roller pair 52, the auxiliary roller pair is brought into the transfer position by pivoting the pivoting lever 54 (see FIG. 15, compare with FIG. 4). In this case, the thread reserve provided for the storage device 44 is used up. The further process of thread return and piecing is the same as that described with reference to FIGS. 4 to 8. However, care is taken to ensure that the piecing thread 30 does not leave the clamping line of the pair of auxiliary rollers 52 during this piecing process.

After the piecing process has been carried out, the pivot lever 54 returns to the position shown in FIG. 13 with the piecing thread 30 held in the pair of auxiliary rollers 52. The pivot lever 45 is now also brought into the position shown in FIG. 13 and takes over the start of the piecing thread 30 in this position. The thread length released when the pivot lever 54 returns to its thread take-up position (according to FIG. 13) is stored in the storage device 44 .

If a thread break is to be remedied, which is done with the aid of the thread unwound from the bobbin 132, the pivot lever 54 can be pivoted to the bobbin with the auxiliary drive roller 24, since the beginning of the piecing thread 30 is held by the thread clamp 451.

In principle, a piecing device of one of the designs described above can be provided individually for a spinning station. In the case of the maintenance devices 2 which are customary today and which run along a multiplicity of spinning devices of an open-end spinning machine, on the other hand, the piecing reel 3, the feed device 4, the feed device 5 and the return delivery device 20 are arranged on the maintenance device 2.

Claims (48)

1. A method of joining a thread in an open-end spinning device, in which a thread is returned to the spinning device (1) either from a spooling device (13) on which it was previously wound onto a spool during the spinning process, or from a special piecing spool, characterized in that the thread (30) drawn off the special piecing spool (3), when returned during the piecing process, is brought to near the spooling device (13), from which it is returned to the spinning device (1) along a return path which coincides with the return path of the thread drawn off the spool (132), the thread (30) drawn off the piecing spool (3), after the join has been made, is first subjected near the spooling device (13) to the action of a controllable draw-off means and is removed, and the thread (10) subsequently delivered by the spinning device first reaches the full drawing-off speed before it is subjected to the action of the normal spinning drawing-off means and transferred to an empty former in the spooling device (13), when the excess portion of thread and the join are cut off and removed.
2. A method according to Claim 1, characterized in that the piecing thread is slowed down while being drawn off the piecing spool.
3. A method according to Claim 1 or 2, characterized in that the piecing thread is mechanically conveyed from a stand-by position to the common return path.
4. A method according to Claim 3, characterized in that, in order to supply the piecing thread, a mechanical supply device holding the piecing thread is moved to the beginning of the common return path.
5. A method according to Claim 4, characterized in that after the piecing thread has been supplied to the mechanical supply device, a loop of thread is formed in front of the supply device and is used up when the supply device moves to the beginning of the common return path.
6. A method according to one or more of Claims 1 to 5, characterized in that after a sufficient length of piecing thread for piecing has been supplied to the common return path the piecing thread is clamped between the piecing spool and a mechanical supply device and is cut between this place and the mechanical supply device, and the resulting free end of the thread portion extending to the mechanical supply device is held pneumatically and, after piecing and delivery of the pieced thread to the spool, is cut off and removed pneumatically.
7. A method according to one or more of Claims 3 to 6, characterized in that the pieced thread is first drawn off the spinning device by a mechanical supply device and is then transferred to a pair of draw-off rollers between the spinning device and the supply device for the spinning draw-off process, after which the thread drawing-off speed brought about by the mechanical supply device is reduced as compared with the thread draw-off speed brought about by the pair of draw-off rollers and the excess thread is formed into a loop, after which the thread is cut between the loop and the supply device and the cut thread is then removed, whereas the thread connected to the spinning device is transferred to the spool.
8. A method according to one or more of Claims 1 to 7, characterized in that the piecing thread for piecing is supplied mechanically, in conjunction with a change of spool, to an air flow which inserts the piecing thread into the open nip line of a pair of auxiliary rollers, after which the piecing thread is stopped near its leading end and a loop is formed from the piecing thread, which continues to be supplied as before, after which the continued supply of piecing thread is stopped and the pair of auxiliary rollers, with closed nip line, are brought into the range of action of a stream of suction air, thus using up the loop of thread, after which the pair of auxiliary rollers is driven and the piecing thread is simultaneously drawn off the piecing spool and forms a piecing reserve while the leading end of the piecing thread is returned to a stand-by position inside the spinning device, whereupon the piecing thread is cut in the transport direction in front of the pair of auxiliary rollers and the thread end extending to the pair of auxiliary rollers is subjected to a stream of suction air, followed by piecing by releasing the fibre supply and the piecing reserve, after which the pieced thread is drawn off the spinning device at increasing speed by the pair of auxiliary rollers and supplied to the suction-air stream, whereupon the pieced thread is transferred to a pair of draw-off rollers between the spinning device and the pair of auxiliary rollers, after which the pair of auxiliary rollers is delayed so as to form a loop of thread between it and the pair of draw-off rollers, and the loop is held pneumatically and cut off the thread end extending to the afore-mentioned suction-air stream, so that the said thread end is removed, after which the newly produced thread end is transferred to the empty former, which has meanwhile been newly inserted.
9. A method according to one or more of Claims 1 to 8, characterized in that, in conjunction with a change of batch, a change of spool is performed in two steps, the full spool being ejected from the spooling device in a first step and the empty former being inserted into the spooling device only after the spinning device has been prepared for a new batch and piecing has been initiated by means of the piecing thread drawn off the piecing spool.
10. A method according to one or more of Claims 1 to 9, characterized in that, in conjunction with a change of spool, the piecing process is monitored for a certain time after the pieced thread has been transferred to the empty former and if the thread breaks during this period the spinning device is stopped, after which the turns wound onto the empty former during the preceding piecing process are unwound again from the empty former, followed by a new piecing process, without another change of spool, using the piecing thread drawn off the piecing spool.
11. A method according to Claim 10, characterized in that the thread is monitored while the piecing process is being monitored.
12. A method according to Claim 11, characterized in that the thread is monitored near the spooling device.
13. A method according to Claim 11 or 12, characterized in that the thread is monitored with regard to axial motion.
14. A device for joining a thread in an open-end spinning device (1), comprising a spooling device (13) comprising a spooling roller (130) for driving a spool (132), a return device (20) for returning the end of a broken thread (10) to the spinning device (1), a piecing spool (3) and a piecing thread (30), a supply device (5) for delivering the piecing thread (30) to the return device (20), and a laying device (4) for laying the piecing thread (30) in front of the supply device (5), for working the method according to one or more of Claims 1 to 13, characterized in that the supply device (5) comprises a pair of auxiliary rollers (52), of which one roller is adapted to serve as a drive roller (24) for the spool (132) lifted off the spooling roller (130) and is drivable by a controllable drive (404).
15. A device according to Claim 14, characterized in that in the pair of auxiliary rollers (52) the roller constructed as the drive roller (24) for the spool (132) is disposed at the free end of a rocking lever (54).
16. A device according to Claim 14 or 15, characterized in that the roller (520) of the pair of auxiliary rollers (52) which is not allocated to the spool (132) can be lifted off the roller constructed as the drive roller (24) for the spool (132).
17. A device according to one or more of Claims 14 to 16, characterized in that the roller constructed as the drive roller (520) for the spool (132) in the pair of auxiliary rollers (52) is interchangeable and has a first longitudinal portion (240), which cooperates with and has a shape adapted to the spool (132), and a second longitudinal portion (241), with which the other roller (520) in the pair of auxiliary rollers (52) cooperates.
18. A device according to Claim 17, characterized in that the first longitudinal portion (240) has a greater diameter than the second longitudinal portion (241) and the drive (404) of the pair of auxiliary rollers (52) is controllable so that when a break in the thread is mended, the peripheral speed of the first longitudinal portion (240) is the same as the peripheral speed of the second longitudinal portion (241) during piecing in conjunction with a change of spool.
19. A device according to Claim 18, characterized in that when the first longitudinal portion (240) is conical, the cylindrical second longitudinal portion (241) is adjacent to the greater diameter of the first longitudinal portion (240).
20. A device according to one or more of Claims 14 to 19, characterized in that the laying device (4) comprises a thread-retaining device (40, 44).
21. A device according to one or more of Claims 14 to 20, characterized in that the laying device (4) comprises a pair of drivable delivery rollers (40).
22. A device according to Claim 21, characterized in that the pair of delivery rollers (40) and the pair of auxiliary rollers (52) are allocated a common drive motor (404) to which the pair of delivery rollers (40) is connected via a controllable coupling (402).
23. A device according to one or more of Claims 14 to 22, characterized in that the driven rollers (400, 24) in the pair of delivery rollers (40) and the pair of auxiliary rollers (52) are drivable at the same effective peripheral speed.
24. A device according to one or more of Claims 14 to 23, characterized in that the laying device (4) comprises a storage device (43, 44).
25. A device according to Claim 24, characterized in that the storage device is in the form of a suction-air opening (43) adapted to operate between the pair of auxiliary rollers (40) and the pair of delivery rollers (52).
26. A device according to Claim 24 or 25, characterized in that the storage device (43) is disposed between the pair of delivery rollers (40) and the pair of auxiliary rollers (52).
27. A device according to Claim 26, characterized in that the suction-air opening (43) is disposed in a stationary position near the pair of auxiliary rollers (52), between the pair of delivery rollers (40) and the auxiliary rollers (52), and is controllable by a switching-off device (430).
28. A device according to Claim 26 or 27, characterized in that a thread-cutting device (413) is provided in the conveying direction in front of the storage device (43).
29. A device according to Claim 28, characterized in that the thread-cutting device (413) is disposed between the pair of delivery rollers (40) and the storage device (43).
30. A device according to one or more of Claims 14 to 29, characterized in that the laying device (4) comprises a pneumatic thread feeder (41) disposed in front of the pair of auxiliary rollers (52).
31. A device according to Claim 30, characterized in that the pneumatic thread feeder comprises a thread guide tube (41) extending from the pair of delivery rollers (40) to the pair of auxiliary rollers (52).
32. A device according to Claim 31, characterized in that the suction-air opening (43) opens laterally into the end of the thread guide tube (41) facing the pair of auxiliary rollers (52).
33. A device according to one or more of Claims 28 to 32, characterized in that the thread-cutting device (413) is disposed in the thread guide tube (41).
34. A device according to one or more of Claims 31 to 33, characterized by a controllable thread clamp (42) which is disposed near the end of the thread guide tube (41) on the side of the suction-air opening (43) remote from the pair of delivery rollers (40).
35. A device according to Claim 34, characterized in that the thread clamp (42) is disposed in the thread guide tube (41).
36. A device according to Claim 34 or 35, characterized in that the controllable thread clamp (42) comprises a movable clamping part (421) consisting of resilient material.
37. A device according to one or more of Claims 21 to 36, characterized in that the laying device (4) comprises a compressed-air nozzle (411) directed towards the nip line of the pair of auxiliary rollers (52) and adopted to operate between the pair of delivery rollers (40) and the pair of auxiliary rollers (52).
38. A device according to Claims 31 and 37, characterized in that the compressed-air nozzle is constructed as an ejector nozzle (411) which opens into the end of the thread guide tube (41) facing the pair of delivery rollers (40).
39. A device according to one or more of Claims 16 to 38, characterized in that the drive (53) of the liftable roller (520) of the pair of auxiliary rollers (52) is connected for control purposes to a common control device, together with the compressed-air nozzle (411).
40. A device according to one or more of Claims 31 to 39, characterized in that the thread guide tube (41) is adapted in shape, at its end facing the pair of auxiliary rollers (52), to the nip of the said pair of auxiliary rollers (52).
41. A device according to one or more of Claims 14 to 40, characterized by a control device (6) with a number of control programmes (60. 61, 62, 63) which can be called depending on whether a thread breaks immediately following a change of spool or independently thereof or whether a spool is to be changed in conjunction with a change of batch or independently thereof.
42. A device according to one or more of Claims 14 to 41, characterized in that the thread-retaining device is constructed as a storage device (44) and the laying device (4) contains a thread clamp (451) movable from one to the other side of the pair of auxiliary rollers (52), which are in the receiving position.
43. A device according to one or more of Claims 14 to 42, characterized by a monitoring device (222, 432) monitoring the pieced thread.
44. A device according to Claim 43, characterized in that the monitoring device (222, 432) is associated with a thread-removal device (22, 431) for removing the thread before transferring it to the spooling device (13).
45. A device according to Claim 44, characterized in that the monitoring device (432) is associated with the suction-air opening (43).
46. A device according to one or more of Claims 43 to 45, characterized in that the monitoring device (222, 432) is constructed as a thread-travel monitoring device so that it can distinguish between an axially immovable and an axially movable thread.
47. A device according to one or more of Claims 14 to 46, characterized in that the piecing spool (3), the laying device (4), the supply device (5) and the return device (20) are disposed on a maintenance device (2) which is movable along a plurality of adjacent open-end spinning devices of an open-end spinning machine.
48. A device according to Claim 47, characterized in that the suction-air opening (43) is connected to a source of negative pressure on the machine side.

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